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Sept. 3, `1946. y _ A Rv. E. cHoATE ETAL ' 2,406,944 VEHICLE @riginal Filed- sepi. 21. 1940 9 sheeis~sneei 1 Sept. 3, .19.46. R. E. cHoATE ErAL 2,406,944 VEHICLE Original Filed Sept. 21, 1940 9 Shee‘bS-Shee‘i‘l 2 gmc/www5 Sept 3, -1946. ` R. E. CHOATE ÈT Al. ' VEHICLE original Filed sept. 21’, 1940 2,406,944 " 9 sheets-sheet s s Sept. 3, 1946. R. E. cHoATE E'rAL . VEHICLE Original Filed Sept, 2l, 1940 , ‘ 2,405,944 ' 9 Sheets-Sheet 4 - Sept. 3, 1946. R. E. CHOATE ET .M_v 2,406,944 ' VEHICLE Original Filed Sept. 2l. 1940 .I_Mm-Hlnuî QQ NS @M m5 SQ 9 Sheets-Sheet 5 SePtl- 3, 1946- R. E. cHoATE ET Al. 2,406,944 VEHICLE Original Filed Sept. 2l, 1940 9 Sheets-Sheet 6 ‘ ' à. E. cHoATE ETAL ' 2,406,944 VEHICLE Original Filed Sept. 21, 1940 Fim-5-a 9 Sheets-Sheet '7 Sept. 3, "1946.v R. cHoA'rE Ei- AL ' 2,406,944 -V EHICLE Original Filed sept; 21, 1940 55 9 sheets-)sheet 8 » l Sep-t3, 1946- R. E. cHoATE ET_AL ' ' ì 2,406,944 VEHICLE Original Filed Sept. 2l. 1940 9 Sheets-Sheet 9 Patented Sept. 3„ 1946 2,406,944 UNITED STATES PßsrlazN'r> OFFICE Y VEHICLE i R03/ E. ohoate‘ana Ellsworth W. Austin, cedar ' Rapids, assìgnors to >LaPlant-Choate Iowa, l Manufacturing Company, Incorporated, Cedar ' _Rapids, Iowa; a. corporation of Delaware Crigînal application September 21, 1940, Serial . ¿f No. 357,672, now Patent No. 2,347,882, dated ’ May 2, 1944. Divided and this application Sep , tomber 13, 1943, Serial No; 502,114 (Cl. ISO-51) 12 Claims. 2 is well distributed over the ground-engaging Our invention relates to a vehicle particularly adapted for excavating, transporting;> discharg ing and leveling earth orz comparablematerial, Wheels.` this application being a division of our applica tionSerial No. 357,672, iiled` SeptemberrZl, 1940,; , . „ ‘ _‘ l `- « ` ¿ `yet which is >sufliciently flexible 1go-permit ready for an Excavator which issued as‘ Patent No. 2,347,882. I Anotherobject of our invention is‘the pro vision of a vehicle in which ‘the drive from the power-plant to the Wheels i‘s'generally-` positive maneuvering. ` ' ` ` ‘ Another object of our invention is the pro `At the present time it is customary in `most vision of a vehicle- capable of being driven in 'a commercial operations to provide the excavating "machine ¿with a -separate' tractor, usuallyof the' 10 reverse direction for maneuvering‘iin cramped ,track-laying type,` arranged at the front of the excavator, to‘ draw the excavating machine over the ground during most ofthe operation. Some quarters. " Í ‘ - _ A further object of our invention is to provide an excavator which is largely automatic oper times, especially during actual digging, if power ation sothat a single operator _can handle large ` I « 1` is scant, an additional tractor is brought `up be-- 15 loads at very high speed.` Another 4object, of our invention is to provide hind the excavator and acts as a temporary an excavator in which the amount of excava pusher or booster. This arrangement is feasible tion is automatically regulated for maximum where extra operators and equipment _are avall performance of the vehicle. able and where there is a good deal of room for maneuvering. There is no satisfactory -revers- A' 20 ing action available, however, and even ifV the ` ¿ The foregoing and other objects are attained in the embodiment of the invention illustrated in tractor is operated in the very slow speed re verse, steering is diflicult partly because of the the drawings, in which type of draft hitch employed. form of an excavator embodying the objects `of ` , Fig. 1 is a side elevation of a vehicle in the In ,long haul operations, this is of little importance, but in?" 25 short haul operations, the time spent turning around at the end of the digging trip and at the end of the return trip may amount to ten or' our invention; „ V , Fig. 2 is a plan> of the excavator shown in Fig. 1; , \ Fig. 3 is a cross-section the planes of which are indicated by the lines 3-3 _of Fig. 2; ' twenty per cent of the total time. ,An excavator Fig. 4 is a cross-section the planes of which which can be operated and accurately steered`£` ,30 are indicatedby the line 4-4 of Fig. 3; ` ` c at high speed in reverse is obviously advanta Fig. 5 is a cross-section the plane of which is geous in this type of work. ` , ` indicated by theA line 5,-5 of Fig. _4; ~ The power requirements of a vehicle ofthis Fig. 6 is a cross-section the _plane of which is type are very severe. On relatively long hauls a representative size of excavator will carry about? thirty cubic yards of material about forty miles indicated b_y the line 6-M6 of_F_ig, 4; v , Fig. 7 is a plan, portions `of the` enclosing cas ing being removed, of the rear .portion of our per hour. -This is accomplished with thevehicle going rapidly with respect to the engine. During excavator; 4 ` ` _ ‘ , c Fig. Bis a side elevation of a motor vehiclepref excavating, a deep cut in hard material may re quire the full enginepower at maximumengine erably for use with `our excavator; speed yet at a very low vehicle speed. __A number g ì ` Fig. 9 is a diagrammatic plan of the cable `ar rangement of our excavator; ` of different gear ratios are advisable, but changes « ` , Fig. 10 is a schematic dìagram‘of the controls ` from one ratio to another should be made `almost instantly to avoid loss of~ momentum.l Hence an 45 of Fig. our excavator; 11 is a schematic and diagram of additional , _ automatic transmission is highly desirable. y One of the objects of’our invention is the pro visionfof an improved vehicle particularly >adapt controls of our excavator especially for‘regulat ing the amount ofA excavation. ` ' ' For the purposes of illustration, our vehicle has been shown in the form of an excavator in Another object of our invention is the provision y50 cluding a maingframe and main bowl structure, of a vehicle provided with its owrrbooster` power the elements of vwhich are articulated for rela plant. > tive motion aboutïa transverse axis and which are ed for use as an excavator: Still ’another Y i _ object of` `our p invention ‘- is >the provision. of a vehicle in- which `the y‘power-plant .is arrangedsothat the `weight ofthe-power plant provided with means ior'controlling such motion. Each ofthe elements is supported on ground 55. engaging Whee1s,i_the ._rearpair, of _which are 2,406,944 3 4 driven by an associated source of power, and the front pair of which not only are steerable but are rear wheels. This permits very abrupt turning and sharp maneuvering of the vehicle in cramped -quarters. The steering member 3I is primarily a hollow casing having (Fig. 5) a king pin 34 driven from their own associated source of power. The sources of power are under the control of the vehicle operator and transmit their driving force through hydraulic couplings and automat ically shiftable ratio-changing transmissions re sponsive to the speed of the respective driven wheels. The drive is also transmitted through. reversing gears under operator control and therein also mounted Within a central mast 33 forming part of the main frame. The king pin 34 is extended to form a pívot connection with a knuckle frame 36 preferably integral with the steering member 3I. In order to eñ'ectuate relative steering rota tion between the main frame mast 33 and the steering member 3I, _there is mounted on the casing 3| within a steering compartment 3l’ a bevel ring gear 38 with which meshes (Fig. 6) a through diiîerential gears under automatic con trol responsive to the steering for locking the dif ferentials. The earth-handling devices, that is, the main bowl, the pusher and the auxiliary bowl, are power-actuated by operator-controlled cable Winches and hydraulic cylinders. The .excavator structure II is supported upon 'steering bevel 39 journaled on a collar 4I and also meshing with bevel ring gear 42 within the compartment and fast on the mast 33. An ex tension 43 of the collar 4I forms a pivotal mount ing for a piston rod 44 of a hydraulic steering a pair of rear ground-engaging wheels I2 and a pair of front ground-engaging wheels I3 -alnd is made up o1” a rear, main bowl section I4 articu 20 structure (Fig. 4). A double-acting steering cyl inder 41 is at one end mounted on a pívot pin lated to a front, main frame section i6 for rela 49 fast with respect to the steering member 3! tive rotation about a transverse horizontal axis and disposed on .an extended bracket 5I mate I'I. Relative rotation about the >axis is controlled rially spaced from the king pin 32. by double acting hydraulic piston and cylinder Upon appropriate control of oil ñow to and structures I8 pivotally mounted on the frame I6 25 from the chambers ofthe cylinder 41, the pis and connected through stopped bell-cranksA i8 to ton rod 44 is advanced or retracted to rotate the the main bowl section I 4. The various instru extension 43 and to move the bevel 39, so that mentalities within and associated withthe main relative rotation takes place between .the ring bowl, including the bell-cranks I9, are substan tially as shown in the above-identiñedAustin ap plication. These instrumentalities generally com-v prise an earth discharge or pusher member 2I which is translatable within the main bowl I4 and which is connected by an articulation 22 to an earth-retaining member 23 or auxiliary bowl or front apron which in turn is connected to the main bowl through a pair of links 24, so that upon forward movement of the pusher 2i the .30 gears 38 and 42, thus producing relative rota tion between the steering member 3l and the mast33 of the main frame. The gear reduction employed is at a ratio of ,two to one, so that, for 90 degrees angular motion of the extension 43, 180 degrees angular motion of the `steering member with respect to the steering mast‘3l is provided. Also by use 0f this mechanism, and because of the resistance to flow of the hydraulic front apron 23 rises, while upon return or rear fluid utilized, the steering member 3 I, despite ex ward translation of the pusher 2I the front apron 40 traneous shocks, remains substantially in the se 23 closes. . lected position, although the operator can, if de While the front apron is open, material is either discharged from or loaded into the >main bowl over a cutting yedge 26 .disposed .approxi sired, permit some seepage or leakage in order that a dashpot effect may be provided. Steering movement is imparted from the steer mately midway of the length of the main bowl 45 ing member 3I to the front ground-engaging structure'. Upon appropriate operation .of the wheels I3, through supporting structures which hydraulic cylinders I8, the cutting edge 25 can be connect the front wheels to the `rest of .the vehi raised to its carrying position as shown in Fig. 1, cle. These supporting structures are substan or can be lowered therefrom to a maximum tially identical on opposite sides of the center, cutting position below the surface of the ground, 350 and hence a description of one applies to both. such movement being >accompanied by relative Mounted upon the steering member v3l are par rotation .of the main bowl section I4 with respect allel rods 56 serving >as pivotal mountings for a to the main frame section I6 about the transverse axis I'I and also about the rotational axes of the rear wheels I2 and the front wheels I3. When the .hydraulic cylinders I8 are notl actu ated, but `the liquid is blocked therein, they func tion as restraining or locking means to prevent unwanted or erratic relative rotation of the main . 5 pair of support levers 51 and 58 fulcrumed on the steering member at their inner ends and at their outer ends connected by parallel pivots 59 and 6I to the. enlarged plate end 62 of an axle tube 63. On lthe axle tube are disposed bearings 64 and 65 rotatably supporting a wheel 66 provided with detachable connectors 61 securing it to a bowl and main frame members, thereby preserv rim 68 on which .a ground-engaging pneumatic ing the selected position of the various parts Ob tire 69 is mounted. under the control of the operator. By this arrangement not only does the tire, The forward portion of the main `frame 4Iii is rim and wheel unit revolve upon the axle tube 63, connected to and includes a steering member 3l but likewise the wheel assembly rises and falls which is mounted for .relative .rotation -with re-»` with respect to the steering member 3| as per spect `to the main frame vabout a vertical 'axis 32, mitted by the rising and falling movement of the and since the front wheels I3 are .connected to the steering member there is thus provided a means for effectuating steering movement of the entire vehicle, the extent ofv steering motionof. .the front `wheels being a rotation. of :substan tially 90 degrees in either ldirection from 'the straight-ahead position, :so `that Ithe vehicle :can be -steered with its front ‘wheels traveling 'in a direction at Aright angles to :the direction v.of the levers 51 and 58. Thus, rotational movement of the steering member about the central vertical axis 32 is accompanied by a corresponding move ment of the wheels in unison therewith, to ac complish steering of the excavator while rising and falling movement of the wheels 'to accom modate for irregularities in the ground is ‘per mitted. This accommodation is resiliently re strained. Interposed between pads on the steer 2,406,944. . ing member 3| and pads onthe plate 62 is alpair of coil springs 1| for transmitting the weight of the vehicle to the ground-engaging wheels. An other pair of springs is symmetrically arranged, and with this suspension arrangement the steer ing axis 32 may remain substantially in a ver tical position while either of the front ground f engaging wheels can accommodate itself to irre to a transmission shaft |06 which extends through the steering housing 3| and which car ries a bevel side gear |01. The driven member |04', however, is connected to a bevel side gear |08. Together these are freely rotatable with 'f respect to the shaft |06, yet the gear |03 is con nected with the bevel gear |01' through pinion gularities in the terrain independently of simi gears |09 Arestrained against planetary rotation and mounted in journals within the housing 3|. lar accommodating movements `by the other wheel. ` Y With this arrangement, when the disc |0| is in neutral position, no power is transmitted from the driven shaft 91 to the shaft |06. When the disc IDI is in frictional engagement with the disc |03, power is transmitted directly to the shaft |06 and turns it in the same direction as the engine crank-shaft 9| rotates. When, however, the disc |0| is in contact with the disc |04, this latter disc then rotates in the same direction as the engine crank-shaft, but this direction of rotation is re versed through the pinion gears |09, so that the gear |01 and the shaft |06 are then rotated in a direction opposite to the direction of `rotation of the crankshaft 0|. There is, however, no ` In order to provide a support for the opera to-r’s station and for propulsion mechanism, the steering knuckle frame 36, approximately mid way of its height, is extended to provide a sub stantially horizontal beam -platform »16 which forms the floor of an operator’s cab 11 containing ^a seat 18 for the operator and a steering wheel 19, together with other control instrumentali ties, and from which the operator can see not only ahead but also behind into the earth-ex cavating structure, for full visual observation of the entire operation. , 6 The driven member |03. is connected directly - Situated beneath and partially supported by speed changeby means of this reverse gear trans mission, so that there is provided either a com plete neutral disconnection or full power trans mission in either of two opposite directions. This is all under the control of the shifting fork supplied to the vehicle. The engine is prefer 30 |02 which is itself controlled by the vehicle oper ator. ably water-cooled, with the radiator structure the floor beam 16 is ya source of power, such as an internal combustion engine 0|. This power plant is peculiar or individual ,to the front ground engaging wheels which are driven thereby, and furnishes substantially half of the total power In addition to the reversing mechanism, 4we provide a ratio-changing mechanism between the source of power and the ground-engaging wheels, 82 forming a linkto assist in supporting the en gine, and derives fuel from a tank 83 disposed beneath the driver’s seat 16. The engine 8| not only supplies power directly to the vehicle but also has a power take-off housing B4 from which a shaft 86 projects to drive an air-pump 81 to and this preferably takes‘the form of a spury gear transmission located in a casing I I| bolted on `the rear of the steering member 3| and also forming a‘support for the bracket 5| previously described. Any suitable ratio-changing mecha supply compressed air for operating various in strumentalities and likewise to drive a hydraulic or oil pump 88 for operating other instrumen talities. nism can be utilized, and any desired number of ratios can be afforded, but for example herein we have disclosed an arrangement which is un der the control of the operator or which is auto matically actuated and provides a choice of any one of eight speeds or ratios. This, in conjunc n The engine itself terminates in a standard bell housing 89 in which the engine crank-shaft 9| is journaled and which bolts to a housing 93 for a hydraulic coupling. This comprises a toroidal drive member 94 operating on and with the crank shaft 9| and driving, by hydraulic connection, a tion with the reversing mechanism, affords eight speeds rearwardly and eight speeds forwardly be tween the engine and the ground-engaging ìtoroidal driven member 96 mounted on a driven shaft 91 extending to Va reversing mechanism, wheels. generally designated 98, contained within a hous-, 50 ’ ing 99. This housing is preferably bolted to the coupling housing 93 and to a receiving face on the steering member 3|. ` We prefer that the reversing gear be capable of driving the vehicle in either direction at maxi mum speed and power so that the excavator not only can advance at maximum rate into a nar row cut, for example, but can also retract from such a cut and thus perform a maneuver which cannot be performed by present excavating structures. For that reason, the reversing mech anism takes the form of a driving disc |0| which has a middle, neutral position, as shown in Fig. 5, and may be shifted by a shifting fork |02 in either direction out of the neutral position, either for wardly into frictional engagement with a driven member |03 or rearwardly into frictional en gagement with a second driven member |04. While the driving and driven members engage frictionally, it is not intended vthat they act pri marily as slipping clutches, but rather the inter engagement between the driving member |0| and . either of the driven discs |03 and |04 is relatively abrupt, any large difference in speed being grad - ually absorbed by the hydraulic coupling 93. j In the ratio-changing transmission the trans mission shaft |06 carries a driving dog clutch ||2 under the control of a shifting fork I I3 and mov able from a neutral position into either of two extreme positions in engagement either with a gear || 4 or with a gear IIE. Each of these gears is‘freely rotatable upon the shaft |06 until it is coupled thereto by the dog clutch ||2 upon operation of the shifting fork I I3. Meshing with . the gears is a pair of cluster gears ||1 and H8, respectively, which are fast on a countershaft I I9. Also fast on this shaft is a second shifting dog clutch |2| under the control of a shifting fork |22, so that upon operation of the fork the clutch _ |2`| couples tothe countershaft H9 either of two These in `turn mesh with a . gears |23 and |24. pair of cluster gears |26 and |21 integral with ‘a quill |28 revolving around the transmission shaft |06. Fast on `the quill, so far as rotation is concerned, but shiftably slidable thereon, is a Y,dog clutch |29 under the control of a shifting fork |3| for engaging either of two gears |32 and |33 with the quill. These gears respectively mesh with cluster gears |34 and |36 which are fast on a driven shaft |31. Since there are three shifting forks ‘|I3, |22 and |38, each of which 2,406,944 7 has two shifted positions with a different gear ratio .effective `in each, by appropriately shifting Speed .and smal1 drive axle |56 yet a relatively slow speed of the ground-engaging wheels. We preferably provide means for braking the these forks a total of eight different ratios is vehicle, and, as an example, utilize a portion of obtainable. After the speed ratio has been `established in 5 the wheel housing G9 as a brake drum. Within such drum and pivotally mounted on a brake the transmission casing |||, the drive is taken vfrom the shaft |31 through a pinion |38 meshing with a ring drive gear |39 mounted on a differ plate |63 splined on the axle housing tube 66 are brake shoes |54 which are fluid actuated by an interior cylinder |66 connected by a fluid con ential spider |4| journaled within the steering member 3|. DifferentiaI pinions |42 are carried 10 duit |61 and passages |08 in the axle tube to a connection |59 going to the cperator’s control by the spider [4| and mesh with side gears |43 station in the customary fashion. and |44. Ordinarily, the drive from the ring Not only is a driving and braking structure gear |39 is transmitted to the spider and is di vided evenly by the pinions |42 to the two side employed with the two front ground-engaging wheels |3 from a front engine 0|, but in an en gears |43 and |44 for appropriate distribution tirely similar fashion, except for the steering and to the ground-engaging wheels. Under certain the articulated, resilient suspension, there is pro circumstances, however, we prefer that the dif vided at `the rear of the vehicle an entirely sepa ferential mechanism be rendered inoperative or rate and independent engine |15 which is dis be disabled to divide the power, so that in fact the driving wheels are locked together for rota 20 posed in a rearward extension |11 of the main bowl structure ||. This arrangement behind the tion in unison with the drive gear |39. This is rear ground-engaging wheels l2 is substantially of particular value when the vehicle is negotiat symmetrical about the center of the earth-carry ing very rough terrain with different traction ing structure with the engine disposition rela conditions in different localized areas thereof, and for that reason we provide a differential lock 25 tive t0 the front ground-engaging wheels, so that the weight is at all times uniformly distributed. ing mechanism which precludes any power or The engine |18 is entirely comparable to the en torque differential between the wheels on oppo gine 8| and is similarly provided with a power site sides of the vehicle. take-off |84 and a power take-off shaft |86 which Extending from the spider |4| is a friction disc |46 with which can be engaged a friction disc 30 connects through universal joints |81 and a drive shaft |00 to a winch mechanism |99. This winch |41 axially movable on but splined to the hub of structure is operator-controlled and preferably the side gear |43. Axial movement is provided is provided With a pair of independently actu by a shifting collar |48 having an interengaging ated drums | 9| and |92, each of which is nor serrated connection |49 with a non-rotatable thrust hub abutting the disc |41. The collar |48 35 mally left in a braked position but may be freed for unhampered rotation or can be connected for is controlled for partial rotation by an actuating power driving to the engine |01, all under the lever |5|, so that normally the> actuating lever control of the operator. |5| is in a position with the serrations |49 nested As particularly shown in Figure .9, the winch and the discs |45 and |41 out of engagement. This permits free differentiation. But when the 40 |9| is provided with a cable |95 which extends about pulleys |93 on the pusher 2| to an anchor lever |5| is slightly rotated, the serrations |49 are age |94. Thus, when the winch |9| is energized, relatively moved, thereby translating the disc |41 axially into frictionally locked engagement the pusher 2| is urged forwardly. Similarly, the winch |92 is provided with a cable |91 extending movably locked to the spider |4| and the entire 45 around pulleys |98 on the pusher 2| to an an chorage l 99,-so that when the winch |92 is power differential mechanism therefore revolves as a operated, the influence of the cable |91 is to unit with the driving ring gear |39. with the disc |46 so that the side gear |43 is im From the side gears |43 and |44 the drive on each side of the center line is exactly symmetri cal, so that a description of one side will suffice. rl‘he side gear |43, for example, has its hub extending through and journaled in the wall of the steering member casing 3| to connect with a universal joint (not shown) enclosed in a ball housing |52 from which a sliding joint (not shown) encased in a telescoping housing |53 transmits the drive to a second universal joint (not shown) in a ball housing |54. In this fash ion the drive is transmitted between the relatively stationary steering member and the vertically movable wheel. From the interior of the uni versal joint ball |54 there projects an axle |56 ' retract or withdraw the pusher 2| toward its rear most position. The engine |16 is provided with its own radi ator 20| and similar appurtenances and is con nected to the rear ground-engaging wheels |2 in exactly the same fashion as the front engine 8| is connected to the front wheels, but there is no power connection between the two engines. There is, however, within a housing 203 a dupli cate of the hydraulic coupling 94, and within a housing 204 there is a duplicate of the reversing gear IGI. Also, within a transmission housing 205 there is a duplicate of the ratio-changing mechanism contained within the housing |||. The rear ratio-changing transmission is effective to drive a rear differential mechanism provided with a locking clutch and identical with that af extending to a final gear reduction. This final Cb Ol forded for the front wheels. The rear differen gear reduction is preferably of the planetary tial is disposed within a central housing 201 on type and is entirely contained within the interior which the winch structure |89 is mounted and of the wheel housing 96. It includes a sun gear which is included in and connected to the main |51 at the end of the axle |56, which meshes with frame || of the excavator. The rear wheels |2 a plurality of star gears |50 journaled on a spider o are suitably provided with ñnal gear reductions journaled within the axle housing tube 63 and |59 stationary with the axle housing tube 63 within the wheel housing 293 and, although they and in turn meshing with a driven ring gear |5| fast on the wheel housing 66 and enclosed by a independently articulated for rising and falling are mounted for rotation, are not steerable nor cover plate |62. By this arrangement of final movement due to road irregularities. drive gears it is possible to have a relatively high 75 Except, therefore, for the steering and suspen A2,406,944: 10 .i9 operator, the torque reactions can be utilized for sion mechanisms, the _rear ground-engaging relatively rotating the parts of the structure. The wheels l2 are driven from their separate engine and are operated in` exactly the same fashion as individual controls for the engines are particular ly valuable in operating the vehicle where very sharp turns are made and especially where the are the front ground-engaging wheels and are provided with identical control instrumentalities in every respect. All of the control instrumen talities for the rear engine |16 are brought for.. terrain is exceedingly rugged and contains chuck _holes or mud holes, since, by selective application vof the motive power, advantage may be taken of wardly and are grouped with the control instru the most favorable traction. But for all ordinary mentalities for'the front engine 8| within and for operation by an operator in the cab `11.Y 10 purposes under reasonably favorable conditions, both of the controllers 25| and 251 are operated The general operation `of the control instru in strict conjunction. mentalities Vwhile partially at the discretion of i For controlling the steering of the vehicle, the the vehicle operator, is also partially automatic Aoperator is provided with the steering wheel 19 Vin response to various selected functions, and, 15 which is connected through a resilient means, while the control elements themselves are illus such as a spring 262, with a bodily movable fol lower valve 263. This follower valve controls the flow of hydraulic lluid through conduits 264 ih Fig. 10. and 266 to opposite ends of the cylinder 41, so Preferably, all of the control instrumentalities are arranged within convenient operating dis 20 that as the steering wheel 18 is turned, the fol lower valve 263 produces an equivalent displace tance of the operator stationed within vthe cab trated in the remaining figures, they are diagram matically shown in theirfunctional relationship 11 and are connected as diagrammatically illus trated in Fig. l0. To control `the power output ' ment of the cylinder and, correspondingly, an equivalent turning of the ground-engaging wheels. The wheels consequently are turned by 25 power and are held in positions at all times cor of the front engine 8| there is provided a throttle or governor controller 25| constituted by an op responding to the turned position of the steering erating handle connected by linkage 252 to the springi 253 of an engine governor 254. By vary ing the tension of the spring, the effector the governor 254 on the'fuel supplier '256 of the en wheel. » ' To supply not only the cylinder 41 but likewise the other hydraulic instrumentalities with a sup gine 8| is varied. Thus, for any given or set po 30 ply of hydraulic ñuid, the pump 88 has its intake 261 extending to a tank 268 and discharges sition of the lever 25|, the engine is automatical through an outlet conduit 269. A by-pass check ly maintained by the governor 254 at substan valve 21| regulates the pressure within the out tially the established level of output. Similarly, let conduit, returning any excess of fluid to the and arranged in very Vclose juxtaposition to the lever 25|, is a controller 251 which is connected 35 tank 268. A follower valve pressure pipe‘212 ex tends through a flexible connection 213, to the by linkage 258 to the speed governorl 259 of the follower valve and supplies appropriate chambers vengine |16, the governor being likewise connected within the valve with pressure fluid. A return by a rod 268 to the fuel supplier 26| of thatA en flexible conduit 214 is connected to a ’return gine. Since the levers 251 and 25| are arranged pipe 216 extending to the tank 268'. The port close together, they either can be simultaneously arrangement within the follower valve is such operated as a unit by the vehicle operator so as that as the valve is moved in response to the to produce identical= changes in operating char 4steering wheel rotation, the pressure fluid is com municated through the valve body 211 to the acteristics of both engines, or can be individually operated for different power output `from each engine. _« A . For usual operation of the vehicle, the control 1ers 25| and 251 are operated together and uni formly, so that both engines 8| and |16 produce substantially equivalent amounts of power and 45 appropriate portion of the cylinder 48, so that for any degree of steering wheel rotation the l front wheels are steered an equivalent amount through the intervening servo action of the fol lower valve and the hydraulically actuated cyl produce substantially equal torques at the driv 50 inder. Since the steering of the vehicle is of the cen ing wheels. In this type of operation the engine 3|, in propelling the vehicle forward, produces a torque reaction which tends to move the forward portion of the main frame in a counter-clockwise direction (Fig.v 3) about the axis of the front, ground-engaging wheels, whereas the rear engine |16 produces Va driving torque reaction which tends to rotate the rear portion of the main frame and main bowl structure also in a counter-clock wise direction (from the same viewpoint) about Vthe axis of the rear wheels. These torque-reac tions, being exactly equal, neutralize each other and do not tend to produce any rotation about the transverse axis |1. Y »- ' " - tral pivot or “fifth wheel” type, it is deemed desir able progressively to limit the amount of turn ing angle with increasing speed, so that, while the vehicle is fully maneuverable when it is oper ating at low speed and in cramped quarters, the amount of' turning which can be effected at higher speeds is progressively decreased as the vehicle speed increases. Since the excavator is intended to haul very heavy loads of earth at a relatively high rate of speed, an automatic means is pro vided for insuring stability by precluding exces sive steering movement; that is, by reducing the range of possible steering as the speed is in ‘ Under other types of operation, however, the two engines 8| and |16 are individually operated by individual manipulation of the levers 25| and 251 to produce different torque effects upon the front wheels and the rear wheels; and 4since the driving torques are in different amounts, the cor-,_ responding reactions tendV to induce a relative rotation of the main frame and main bowl struc ture about the transverse axis |1. This is nor creased. . - . l For this reason, there is driven by the rear wheels I2, or is responsive to the speed thereof, an excavator speed governor 218 which translatesv a controller219 as the vehicle speed increases. Themovernent of this controller is likewise trans mitted through a similar control rod 28| fastened thereto andY effective through a link 282 to trans late` a restraining block 283 against the urgency of a‘return spring 284. The block has a cam mally resisted by the hydraulic cylinder; mecha nism I8. Since these are under the control of the 75 face 286 which is contoured to cooperate with a l1 cani- 28‘1 moving simultaneously with an-d fast upon< the follower valve 263. When the parts 12 acting hydraulic chambers `I8. While ordinarily thel operator controls both of the pedals 306 and 301 in unison, this being facilitated by their loca tion in juxtaposition, the operator can, since the soever upon the transverse translatory movement CSI brake pedals are separate, indivi-dually control of the cam 291, and full steering may be obtained. the brakes to facilitate maneuvering of the Ve `But as the speed of the vehicle increases, the hicle. governor 218 actuates the control rods 219 and In accordance with our invention, and in order 28| and», through the connection 232, tensions the to assist in the versatility and maneuverability of spring 294 by translating the block 283 toward the vehicle, we provide means for permitting the are in the position shown in Fig. 10, which is the low-speed position, there is no restriction What the cam 28-1. When that is done, the cam face 286 progressively limits the translatory movement of the cam, and when the cam block is fully in con-tact with the cam 281 the translatory move ment thereof is limited to a predetermined >amount-«for example, 30 degrees of steering of the front wheels each side of center position. Since the steering wheel 19 is connected to the differential mechanisms, such as I4I, normally to function when the vehicle is turning a sub stantial amount but to render the differentials inoperative or to disable them when the vehicle is going in a straight path or approximately so. Further, We preferably arrange matters so that the front differential mechanism and the rear differential mechanism are disabled under difier ent conditions. For that reason, the air pressure necting spring 262, even if the operator should 20 line 302 has a branch line 308 extending to a follower valve 203 by means> of a resilient con ‘operate the wheel 19 beyond the permissible 30 degree limit at high speed, for example, the cam «block 283', being actuated by a superior force, will restore the cam 281 and the follower valve 233 toward central position sufficiently to bring >the steering within the established maximum range at that speed. Thus, while steering is entirely free at relatively low speeds and is re stricted to a predetermined maximum amount at control «valve 309 spring-pressed into inoperative position normally but effective when operated to establish connection between the branch 308 and an air line 3| I extending to an operating chamber 25 3|'2 connected to the lever |5I for operating the locking clutch on the front differential. The branch 308 likewise extends to a control valve 3I3 normally ineffective but, when actuated, ef fective to establish communication through a line ¿high speeds, the range of restriction gradually 30 3I'4 to an operating chamber 3|6 of a similar varies between the low-speed and highespeed character but working upon the locking clutch limits as the cam 291 is contacted by successive lever for Athe differential of the rear engine. ‘portions of the cam face 289. This mechanism Thus, when the valve 309 is operated, the air vprovides an automatically effective means for pressure is eiîective to unlock the front differen vprecluding dangerous steering at the higher 35 tial, whereas when the valve 3|3 is actuated, the ~speeds. air pressure is effective to unlock the rear differ -' Arranged for convenience next to the steer ential. The differential locking and unlocking is ing' wheel 19 is a controller 29| which is effec preferably responsive to steering movement. tive to rotate a conventionally illustrated hydrau Consequently, moving in conjunction with the -lic valve 292 for controlling the supply of hydrau 40 steering piston rod 44 there is a cam block 3| 1 lic fiuid through the supply pipe 269 to the which has a narrow notch 3I`8 on one face, in ‘cylinders I8 connected in parallel, and the dis effective when the steering is straight ahead, but charge of fluid therefrom through the discharge effective upon a turn of approximately 5 degrees, `pipe 216. These are the cylinders which deter either side of center, to translate the valve 309. mine the resistance of they mechanism to torque ' 45 Thus, While the front ydifferential is locked for all freactions of the engines when driving and also steering positions of the front wheels between 5 govern the position of the- cutting edge 26. By degrees left of center and 5 degrees right of cen -appropriately operating the controller 29| the ter, as soon as this ,amount of turning is exceeded, operator can admit, release or hold hydraulic the front differential «is unlocked and the drive fluid within the cylinders I8 to retain the parts 50 of .the front engine is distributed to the two front "locked in position or to move the partsvto any wheels. The. rear differential, however, remains 'selected other position within the total range locked until the front steering approaches a Value ` of Vmovement. approximately 30 degrees either side of center, While many other control instrumentalities on as governed «by a Wide cam notch 3I9 also in the the excavator .can be hydraulically actuated, it is 55 block 3-|1, which »is effective to displace the con preferred, in the present embodiment, to utilize troller 3|3. For all values of steering, therefore, hydraulic actuation only for the steering .and for substantially in excess of 30 degrees left or right l‘the cylinders I8. The remaining power-operated of straight-ahead position, the rear differential is instrumentalities are preferably operated through unlocked and the rear wheels are fully difieren the medium of compressed air. Thus, the com 60 tiated, or the power of the rear engine is then pressor 81, driven by the forward engine 8|, sup distributed to the twov rear wheels in varying 'plies air under a predetermined regulated pres amounts. Upon restoration of the steering mech sure to a tank 30|. From the. .tank a pressure anism toward center position, the rear differen 'line 302 extends to valves 303 -and 304 which con tial is relocked as soon as the range between 30 Itrol the brakes on the front wheels and on thev 65 degrees left of center and 30 degrees right of cen rear Wheels respectively. 'I'he valves 303 and 394 ter is entered, while as soon as the range be Aare provided with individual pedals 306 and 301 tween 5 degrees left of center and 5 degrees right ‘located side by side and convenient to the driver of center is entered, the front differential is ‘in the operator’s cab, so that the front end of the relocked. "device may be braked separately from the rear 70 It is considered desirable to reduce the power end. The braking produces torque reactions voutput of the rear- engine when .the front wheels f quite similar to those produced by the engine are turned or steered a large amount, so that driving forces, except lthat they occur in a reverse 'the driving force of the rear wheels does not tend direction and, unless exactly equal (in which case lto produce a skid of the front end. As a con they neutralize), are also resisted by the double i' 75 vement way of doing this, the air line 3I4 is 2,406,921@ . 13 - abrupt,- andV excessive momentary torque is pri-~ branched to connect to a controller 3|5'e1lîective marilyfabsorbed in the two liquid couplings, one when energized to position a cam 323 in the `path for each power plant. Since these liquid cou of a cam 325 mounted on the control rod-260 of plings are »in part responsive to centrifugal forces, Vthe rear engine.A When the front `wheels are steered more than 30 -degrees either side of center, en dependent upon the speed of the respective en gines, and- since the engines are individually con the controller 3|5 progressively reduces the rear engine speed. ' » trolled through the-controllers 25| and 251, it is possible, by »manually or automatically minimiz Conveniently arranged next to the control lever ing-the power output of `one engine, for example, 29| for raising and lowering the cutting edge, are the rear engine during very sharp turns, to drive the winch control levers. For example, a control substantially by the other or front engine alone, lever` 32| is effective upon a conventional valve so th'at `the direction of rotation of the rear 322 to govern the now from a supply pipe 323 to wheels relative to each other and relative tothe eitherof the oppcmite ends of an actuating charn rear Vengine is not particularly material. That is, ber 324 which is of a standard type repeatedly one engine, when operating relatively slowly, is utilized in the structure and normally centralized to a neutral position by equally acting springs 326 and 321. When thevalve 322 is maintained in neutral position by the median position of the lever 32 |, the winch is likewise in neutral position and transmits no power. However, when the lever 32| is rocked in one direction, air is admit ted to one end of the chamber 324, thereby plac ing the winch in braked position, and when the lever 32| is swung to its opposite extreme posi tion the> winch is connected to power. Thus, the substantially uncoupled by> the hydraulic cou pling, so that the remaining mechanism may be operated in a reverse direction without affecting the one engine. . . Forexample, when the front wheels are turned substantially at 90 degrees to the longitudinal direction of the vehicle, the rear engine can be idle and the front engine can be operated at con siderable speed and power output so as to be - coupled with the front wheels. The front drive can then. bealternated between forward and re verse, to move the forward end of the vehicle in an Varcuate path substantially about the center lever 32| is effective to control one of the winch drums, for example, drum ESI. A lever 33| con'-A trols a standard valve 332 for regulating the sup of the 4rear wheel axis as a turning pivot. `But at ply and discharge of air t0 and from the opposite ends of an actuating chamber 333 which is effec 30. this time the rear yengine, although being re tive to control operation of the winch drum |96. so that by operation of the grouped levers 29 | ,32| and 33|, the operator can effectuate all ofthe usual controlling mo-tions of the earth-carrying and handling structure. Since the vehicle is designed to be operated versely Yand forwardly related to its ground-en-` gaging wheels along with the front engine, is sub stantially ineffective upon the rear wheels be cause its-low speed effectuates a hydraulic un ,¿ coupling. Under these conditions the rear dif ferential is also unlocked. The front end of the vehicle can be operated substantially at right angles and with full poweroutput. This is of as rapidly in a reverse direction as it is in for ward direction, to obviate the necessity of turn considerable importance in maneuvering in ing around,` the control of the reversing clutch IUI for th'e front engine and of the corresponding 40 cramped quarters and where the ground condi tions are quite irregular. Thus, by reason of the clutch for the rear engine >is .simultaneously effec common reverse of the two engines but of the tuated. A reversing lever 334 controls a standard valve 33,6V to provide any one of three positions thereof. In an intermediate, neutral position, separate control of the power output of each and th'e automatic uncoupling feature of the hy draulic couplings at low engine speeds,`there is air from the main 323 is excluded from a front operating chamber 33'! as well as from a rear op provided a somewhat interrelated but extremely flexible and maneuverable power transmission erating chamber 338. The piston in each of system for the excavator. .these chambers is spring-centralized, as previ The hydraulic coupling characteristics, in ad ously described, when no air pressure isy exerted thereupon. The chamber 331, for example, is 550 dition to slippage at low speeds, are of any se lected sort, and the coupling may have turbine leffective to hold the shifting fork |32 of the front or torque multiplying characteristics. The illus reversing structure in neutral position, as shown tration, such as Fig. 5, is diagrammatic ‘but dis in Fig. 5. The chamber 338 for the rear struc closes a type in which there is very little torque ture is identical in operation. u l multiplication but in which the centrifugal cou When, therefore, the lever 334 is moved in one pling is extremely effective. If no material torque direction out of central position, air is admitted multiplication is provided by the hydraulic cou ,to one end of both of the operating chambers 331 pling„we provide other means for changing the and 338, and the shifting -forks are effective to torque ratios. In the present instance, there Yconnect the structure for motion in one direc fore, where the hydraulic coupling itself has very tion, for example, forwardly. When the control little torque changing characteristic, we provide lever 334 is shifted to its opposite extreme posi the eight-speed transmission or some equivalent tion, the air is released from the previously :gear-change mechanism which is ` preferably charged end of the operating chambers 331 and partly automatic and partly under the control 338 and pressure air is simultaneously introduced of the vehicle operator. into the opposite ends thereof so that the shift- Vî ` ing forks controlled thereby are simultaneously vshifted into opposite extreme positions and a >‘reverse coupling or direction of drive is effectu `ated. Thus, the direction of advance of the ve ¿hicle is under the control of the operator by a f single lever, although other parts of the drive are quite separate. While the reversing clutches have .a slight slip page at very high torques, the shift due to the pneumatic controllers 331 and 33B is relatively _ The particular ratio of the front transmission in the casing ||| which is effective at any one time is controlled by a valve shaft 34| rotatable by Van operator’s control levei` 342 or by an op 70 erating rod 343 regulated by a speed-responsive governor 344 actuated by the front ground-en g'aging wheels I3. Thus the position of the shaft 34| is responsive to the speed of the front ground engaging wheels. `That is, the greater the speed of the front wheels I3, the more the shaft 34|l 2,406,944 15 is- rotated from its zero position. But it may be restrained in any selected position by the vehicle 16 eight speeds, the control shaft 34| has nine posi tions. The initial or zero position. is illustrated in Fig. 10 in which none of- the valves is in a or with a latching structure (not shown) . If the position to supply air and all of the control cham lever 342 is held, the corresponding transmission 5 bers 359, 36S and `381 are in neutral position with operator holding the lever 342, either by hand remains inthe selected ratio, but if the lever 342 is free then the particular ratio depends upon the iront-wheel speed. Under governor control, however, the lever does not go into zero position, but at lowest wheel speed, or stopped, the lever occupies first speed position. Manual position the various shifting forks ||3, |22 and I3| like wise in neutral position so that none of the gears is in power-transmitting position. When, how ever, the shaft 34| is moved into its Iirst Posi 10, tion, air pressure is transmitted through the port 351, through the port 363, and through the port ing of the lever in zero position, or neutral, is en 38| simultaneously, in order to establish corre sponding positions of the control chambers and In a quite similar fashion, the control rod 219 the respective shifting forks. When the shaft from the governor 218 which is responsive to the 15 34| is moved to its second position, the ports 351 speed of the rear ground-engaging wheels l2, ex and 363 remain effective, but the port 388 be tends to and is eifective upon the valve control comes effective. In the third position, while the shaft 346 for the rear transmission. A manual port 351 is still eiTective, the port 31| then be controller 341 is in all respects comparable to comes eiîective and the port 382 is effective, there the controller 342 and is located in juxtaposition 20 by duplicating the function of the port 38|. In therewith so that the two controllers 342 and fourth position, the port 354 remains effective, the 341 can be simultaneously actuated by the op port 31| remains effective, .but the port 389 is ef erator, or can be simultaneouly latehed in posi fective as previously the port 388 was eiîective. tion, or can be individually located so that under In fifth position, the port 36| becomes eiïective, rather unusual operating conditions the ratio 25 the port 364 becomes effective in the fashion of of power transmission between the front engine the original port 363, -while port 383 is effective. and the front wheels is diiîerent from the ratio In sixth position, port 36| is eiîective, port 364 of power transmission between the rear engine remains effective, but port 39| is effective. In and the rear wheels. Normally, however, both seventh position, port 36| is eiîective, but port engines are free to transmit power through the 30 312 then becomes effective, while port 384 is con same or approximately the same ratio under au nected. In eighth position, port 36| is effective, tirely possible. tomatic wheel-speed responsive control. port 312 remains effective, while port 392 is effec Since the servo mechanism for translating the tive. position of the shaft 34| into gear positions in In this fashion, the shifting fork ||3 remains the iront transmission is substantially the same 35 in one extreme position for the first four speeds as the servo mechanism for translating the posi and then occupies a second extreme position for tion of the controlling shaft 346 into correspond the second four speeds. The shifting fork | 22 ing gear positions in the rear transmission, a de occupies one extreme position for the first two scription of but one of them applies to both. For speeds, occupies its other extreme position for the example, air from the main 323 is conducted next two speeds, then the first extreme position through supply pipes 35|, 352 and 353 to each of three valves 354, 355 and 356 having substantally the same rotors `but having somewhat different for the subsequent pair of speeds, and ñnally the second eXtreme position for the ultimate pair of speeds. The shifting fork is alternately moved valve casings. The valve 354 is provided with from one extreme position to the other as the but two ports, one port 351 being connected by 46 range of speeds is traversed. Thus, in response a conduit 358 to one end of an actuating cham to the position of the shaft 34|, the ratio of ber 359 comparable to the chamber 324 but con speeds between the front engine and the front nected to the shifting fork I |3, for example. The ground-engaging wheels is automatically or man piston in the chamber 359 is ordinarily in a neu ually controlled. Since the controlling structure tral position, but when air is applied to one end 50,1501- the rear ratio-changing transmission is iden of the chamber it is shifted into one extreme tical, the position of the shaft 346 similarly con position, and that is what occurs when the valve trols the ratio betwen the rear engine and the 354 is ñrst rotated out of its zero position. The rear ground-engaging wheels, either automati valve 354 likewise has a port 36| connected by cally or manually. a duct 362 with the opposite end of the cham 55 Particularly under favorable or normal oper ber 359. ating conditions, the speed transmissions and hy The Valve 355 is provided with alternating and draulic couplings provide an automatic connec spaced ports 363 and 364 which are connected tion between the engines and the remaining driv by ducts 366 and 361 joining in a pipe 368 to ing structure, so that the operator of our ex one end of a control chamber 399. Interspersed 60 cavator need concern himself primarily with but ports 31| and 31.2 join in a duct 313 connected the steering, braking and throttle controls 251 to the opposite end of the control chamber 369. and 25|. He, therefore, can give plenty of at The piston of this chamber is effective upon the tention to and has adequate time to operate the shifting fork |22. winch and hydraulic elevating structures of the The valve 356 is provided with a series of alter 65 earth-carrying portion of the machine. He is nate ports 38|, 382, 383 and 384, each- of which precluded from steering excessively at relatively is joined by its individual pipe to a duct 386 high speeds and is given the assistance of max extending to one end of a controller 381 effective imum drive and traction by virtue of the locking upon the shifting fork I3|. The valve 356 inter differentials under most conditions. Under eX mediate each of the ports 38|, 382, 383 and 384 70 treme conditions, however, the manual controls is provided with a series of ports 388, 389, 39| are available for producing individual driving and 392 each of which is connected by its indi eiîects, so that the full capabilities of the exca vidual pipe to a duct 393 extending to the oppo vator can be obtained. site end of the controller 381. Under extreme operating conditions, or in cer _ Since the ratio-changing transmission has 75 tainl environments, it is advisable to have an 2,406,944 17 18 auxiliary power structure, and we have, there means, we preferably provide a second control fore, illustrated in Fig. 8 a device which is sub stantially the same as previously described in all valve 42| `arranged generally in parallel with the valve 292. The construction of the valve 42| is like that of the valve 292 and hence it receives ñuid under pressure from the duct 212 through respects except that the main frame structure 40| is not articulated between its ends and is` not provided with any earth handling structure .but rather extends simply as a frame to a rigid ` a branch duct 422 and is similarly connected to the discharge pipe 216 by a branch discharge connection at 402 with the rear >engine unit. This vehicle is preferably provided with a rear hook 44113 for facilitating a draft connection with 10 ' the front end of the excavating vehicle shown pipe A423. In a comparable fashion the valve 42| is connected to raise the main bowl I4 by supplying fluid to the duct 4I3 through a branch duct 424, while the -valve is connected to lower the remaining figures. 1 Under some operating conditions, it is consid the main bowl I4'by supplyingfluid to the line is made. Under such circumstances, it -is often such as one of the rear wheels I2, through the medium of a servo or power'multiplying mecha 411 through a branch line 426. The control valve 42| is not provided with any manual lever but ered advisable to provide means for regulating the position of the main bowl I4 with respect to 15 is‘ operated by power since its operating lever 421 is connected to a movable cylinder 428 within> the ground, especially during cutting or excavat-` which a piston 429 is stationarily established by a ing, in accordance with the load as represented piston rod 43| fastened to a fixed support 432. by the speed of advance ofthe vehicle. That The cylinder 428 is centralized with respect to is, under conditions Where very hard going> is encountered, the governed engines furnish max 20 the piston 429 by interior springs 433 and 434. Movement of the cylinder 42B is preferably in _imum power but this may be insufficient to main response to the speed of a ground-engaging wheel, tain the speed of the vehicle -and slower progress advantageous to reducethe depth of cutting in order to maintain the rate of advance of the ve hicle. This is effectuated 25 nism. automatically, d al though manual supervision is retained. Conversely, if the going is particularly easy, the cutting depth can be increased without reduc ing the speed of advance of the vehicle, and un 30 Rotation of the ground-engaging wheel I2 is normally effective through multiplying gear ing 436 to drive a sensitive governor 431 at a rela tively high speed. The multiplying- mechanism which automatically will increase the depth of 436 is desirable since during excavation the speed of advance of the vehicle is usually relatively Yslow and it is advisable, consequently, to make the governor highly responsive during low-speed cut so as to ensure that under all circumstances operation. omitted from; the mechanism without substan- - as the vehicle wheel speed I2 increases, the gov-.- ‘ der those circumstances we provide a mechanism The - governor 431 is connected through linkage 438 to a slide valve 439 govern the vehicle is making the best use of the maxi mum power available from the power source. 35 ing the supply _to andexhaust from the cylinder 438 of a pressure fluid, such as air. This air is Most of the time the »manual supervision can be supplied from the source through‘the duct 302 omitted and the automatic mechanism relied under the control of a valve 44| ywhich communi upon, but there are often unusual circumstances cates with the movable valve 439 through a. flex which can best bemet -by manually controlled 40 ible duct-'442. means‘ if, l‘ A, C 'The‘operation of the ‘mechanism is such that, Since this arrangement‘can be applied to or ernor 431 correspondingly changes its position and moves the valve 439 correspondingly. This shown in a separate diagram in Fig. 11, it being understood that this structure preferably is added 45 movement displacesthe valves 439 toward the right, as seen in Fig. 1l, uncovering the cylinder to the structure as diagrammatically illustrated` 428 to the left of the piston 429 to the atmosphere in Fig. 10. As illustrated in Fig. 11, the main bowl through a port 443 and simultaneously uncover I4 is movable vertically with respect to the main ing a port 444 in the right-hand side of the cham frame I6, in order to move the cutting edge with respect to the ground, and this motion prefer 50 ber 428 to the supply of pressure air through the valve 439. This produces a corresponding trans ably efïectuated by ‘the cylinder and p1ston ar lation of the cylinder V428 in exact proportion to rangement I8 which is connectedto the main the movement of the valve439 responsiveto the bowl I4 by a piston rod 4I I and which is hydrauli governor, and the cylinder movement rotates, cally operated. , i The hydraulic liquid ís obtained from the stor 55 through the lever 421, the valve 42| so that com munication is established between the supply duct age tank 268 from which it is conducted through 422 and the lowering duct 426, while liuìd dis the pipe 261 to the force pump 88 and is dis charge also occurs from ‘the other end of `the charged therefrom under pressure through con cylinder 428, thereupon causing the main bowl I4 duit 269 past the by-pass valve 21| and into the to lower with respect to the ground or to cause controlling valve 292 through the pipe 212. From the valve 292, which is operated by the hand 60 the cutting edge to engage the ground more deeply. 'I‘his normally increases the load upon controller 29|, discharge either is through a pipe the vehicle and slows its advance to the optimum 4|2 into a duct 413 leading to the bottom of the value. cylinder I8 and which when connected is effective to lift the piston rod 4|I and correspondingly 65 When the speed of the vehicle is VVless than the optimum value and the wheel I2 drops below to raise the main bowl I4, or, in the alterna that speed, the governor 431/is correspondingly tive, is through a duct 4|6 into a pipe 4I1 leading to the top of thercylinder I8 and effective to affected, and the valve 439 is translated toward tially altering the remaining portions thereof, it is depress the main bowl I4 with respect to the the leftin Fig. 1l, thereby exposing the port ground. Thus, by operating the hand control 70 444 to atmosphere and connecting the port 443‘ to the supply of air, thereby displacing the ‘mov 29|, as previously described, the operator may, by hydraulic power, raise and lower Vthe main bowl I4 not only with respect to the mainframe able cylinder 428 toward the left in the ligure, rotating the valve 42| in a clockwise direction, andiconnecting the supply duct 422 -to the rais ; i In order to provide an automatically effective -75 ine lduct 424. Thus, `when the speed or the I6 but also with respect to the ground. 2,406,944 19 20 vehicle drops below the optimum value the main restriction. bowl I4 is raised and the cutting edge is lifted is moved in either direction `from its neutral po sition, -the immediate effect is for the extension 46| to permit the lever 462 to rise with the stem 463 under «the urgency of the spring 465. Si with respect to the ground, thereby normally de creasing the load upon the engine and permit ting the vehicle speed to be restored. In accordance with the operation of this mech anism, the position of the main bowl 'is main tained at a value which will afford substantially multaneously, the valve 464 rises, thereby cutting oil’ Vcommunication from the source of air 392 to the servo valve 439 and connecting such valve a constant speed of advance of the vehicle with-A out operator’s supervision and automatically. Y But when the hand controller 29| to atmosphere through a drain duct v46T'. Since, 10 therefore, -despite t-he position momentarily of the But since such automatic regulation is of value valve 439, the cylinder 423 is connected -on both chieñy during excavation, and since the sensi sides of the piston 429 to atmosphere, the cen~ tive governor 437 may be damaged vby over-speed -tralizing springs 433 and 434 are effective in ing when the vehicle is transporting a load or stantly to restore the automatic valve 42| to a dumping a load, we provide lmeans for disabling 15 central, neutral or ineffective position, andthe the automatic structure except during excavation. manual control lever 29| is the sole means of The piston rod 4|4 carries a collar `45| which producing motion of the main bowl I4. As soon, moves with such rod between the maximum ex however, as manual control of the lever 29| is cavating position indicated by the dotted lines relinquished, or the lever is restored to its cen 452 in Fig. 1l, between the maximum raised po tral neutral position, the valve 464 is again po sition indicated by the dotted lines 453 in that sitioned so that the valve 439 is supplied with air ligure, and the intermediate position shown by and vthe automatic 4servo mechanism is restored the solid lines in Fig. 11 wherein the cutting edge to eiiectiveness. is supposedly substantially ñush with the surface By the provision -of this mechanism, therefore, of the ground. it is possible‘to have the lmaximum -utilization of As the collar 45| rises from the central po the engine power, as measured by the speed -of sition illustrated, wherein the cutting edge is advance ofthe vehicle, effective to control the substantially even with the surface of the ground, depth of cut or, in general, the position of the it engages and lifts with it a lever 454 against the main bowl 14, although manual supervision is urgency of a spring 456, and the motion of the ' retained and the automatic control is made in lever is transmitted through linkage 451 to dis effective except for -a `portion of the range -of engage a driving clutch 458 interposed in the movement of the main 4bowl with respect to the ground. drive line between the rear Awheels I2 and the multiplication gearing 436. Thus, as the main We claim:> bowl I4 rises above its ground-level position, the l. A vehicle` comprising: a frame; yrear .wheels clutch 458 is disengaged and no motion is trans for Ysupporting said frame; a first means con mitted to the governor 431. Under these cir nected to drive said rear wheels; front wheels for cumstances, in the event no manual control is supporting and steering said frame; a second exercised, the operation of the governor is such means connected «to -drive said front wheels; as tor produce an extreme displacement of the valve 439 so that the valve 42| is rotated to means for steering said front wheels; and means bring the main bowl 'I4 toits maximum elevated responsive Íto the steering Aof said -front wheels for altering the driving connection of said second position for carriage. means to 'said front wheels. Whenever the governor is 'brought to its declutched or stationary -posi-2. A -vehicle comprising: 'a frame; rear wheels tion, as, for example, when the cutting edge 45 for lsupporting said :fra-me; a ñrst means con strikes an obstruction, or when the load is so nected to -drive'said rear wheels; front wheels for supporting andV lsteering sai-d «if-rame; a second lar operation of the valve 439 promptly brings means `connected to drive -said front wheels; the bowl to highest carrying position. ' means -for steering Asaid front wheels;- and means When the main bowl I4 is lowered to and be 50 responsive to “the Asteering of said ~front wheels for low the central position, and as the collar 45| altering the drivingl connection of Vsaid ñrst great as to slow ’the vehicle materially,” a simi descends, the spring 456 is effective upon the lever 454 and the linkage 451 to engage the clutch 453 and tobring the governor 431 up to means to‘said rea-r wheels. > - 3. A vehicle comprising: a frame; rear wheels for supporting said frame; a iirst lmeans Vcon speed. Below the central position, therefore, the -55 nected to drive -said rear wheels; front wheels for operation is automatically controlled. supporting Aand steering said frame; a second Manual control by the lever 29| at all times means connected -to drive vsaid front wheels; supersedes automatic control when the operator means for s-teerin-g said -front wheels; and means responsive to the steerin-g :of said iront wheels for so desires, and to effectuate that condition the lever 29| is provided with an extension 46| adapt 60 altering -the 4driving connection Abetween said sec ond means and said yiront wheels and between ed to cam against a lever 462 bearing upon the said` ñrst-means and said rear wheels. end of a valve stem 463 joined to the valve 464. 4. A vehicle comprising: a frame; rear Wheels The valve is ordinarily pressed by a spring 466 for supporting said frame; Ya first means .carried into an uppermost position against the lever '462 which in turn presses against the extension 46|. y(55 bysaid frame and arranged to drive said rear wheels; dirigible front wheels for 'supporting said When the hand control lever 29| is in its central frame; a second means arranged to drive said or neutral position, so that the valve 292 is in front wheels; means for steering -said dirigible eiîective to produce any movement of the main wheels; -and means responsive to the steering of bowl I4, the lever 462 is depressed, as is the stem 463, against the urgency of the spring 466, so ?70 said front wheels a predetermined» amount for al that the valve 464 permits free communication ter-ing the driving connection between said second of air from the duct 302 to the valve 439 and the means and said front wheels. servo cylinder 428. Thus, when the hand con 5. A vehicle comprising: -a main frame and troller 29| is in a central or inactive position, main Ibody structure; rear wheels for supporting the automatic .mechanism can operate without 75 said structure; a iirst means` connected to drive 21 25,406,944 said rear wheels; front wheels for supporting and steering said structure; a second means connected to drive said front wheels; means for steering said front wheels; and means responsive to the steer ing of said front wheels a predetermined amount for altering the driving connection of said second means to said front wheels and responsive to the steering of said front Iwheels a different amount for altering the driving connection of said ñrst means to said rear wheels. 22 said rear wheels; a rear differential lock for dis-« abling said rear differential; front Wheels for supporting said frame; a second means for driv ing said front wheels; a front differential for variably dividing power from said second means between said front wheels; a front differential lock for disabling said front differential; means for steering said front wheels; and means respon sive to said steering means for operating said 10 `iront and rear differential locks and for control 6. A vehicle comprising: a frame; rear wheels ling said first means. n for supporting said frame; a ñrst means for driv 9. A vehicle comprising: a frame; rear Wheels ing said rear wheels;` a rear differential for var for supporting said frame; front wheels for sup iably dividing power from said iirst means be porting and steering said frame; driving means tween said rear wheels; a rear difl‘erential’lock 15 connected to drive said front wheels; means for for disabling said rear diiîerential; front wheels steering said front wheels; and means responsive for supporting said frame; a second means for to the steering of said front wheels for altering driving said front wheels; a front differential for the connection of said driving means to said front variably dividing power from said second means wheels. between said front wheels; a front differential 20 10. A vehicle comprising: a frame; rear wheels lock for disabling said front differential; and common control means for operating said front and rear differential locks. for supporting said frame; front wheels for sup porting and steering said frame; driving means connected to drive said rear wheels; means for steering said front wheels; and means responsive 25 to the steering of said front wheels for altering ing said wheels; a rear ratio-changing transmis the connection of said driving means to said rear sion for transmitting power from said first means wheels. to said rear wheelsçmeans responsive to the speed 11. A vehicle comprising a frame; rear wheels of said rear wheels for controlling said transmis for supporting said frame;` dirigible front wheels sion; a rear reversing mechanism interposed be 30 for supporting said frame; means 'for steering tween said first means and said transmission; said front wheels into a position with the planes front wheels for supporting said frame; a second of said wheels approximately transverse of said means for driving said front wheels; a front ratio vehicle; means for driving all of said wheels; and changing transmission for transmitting power means for altering the driving of said rear wheels from said second means to said front Wheels; a 35 in response to said steering means. front reversing mechanism interposed between 12. A vehicle comprising a frame; rear wheels said second means and said front transmission; for supporting said frame; dirigible front wheels means responsive to the speed of said front wheels for supporting said frame; means for steering for controlling said front transmission; and com said front wheels into a, position with the planes mon control means for operating said rear re 40 of said wheels approximately transverse of said versing mechanism and said front reversin vehicle; means for driving al1 of said wheels, and mechanism. ` means for substantially releasing said rear wheels 8. A vehicle comprising: a frame; rear wheels from said driving means upon steering of said for supporting said frame; a ñrst means for driv front wheels approximately into said position. ing said rear wheels; a rear differential for vari 45 R. E. CHOATE'. ably dividing power from said first means between 7. A vehicle"comprising: a frame; rear'wheels for supporting said frame; a iirst means for driv ELLSWORTH W. AUSTIN.