Патент USA US2134673код для вставки
Oct. 25, 1938. G. hLRUssELL; 2, 134,673 HYDRAULIC APPARATUS »Filed March 5, 1930 -\WN ‘ ,Bai A N1 ë? 5 sheets-sheet 1 Oct. 25, 193.8. G. J. RUSSELL 2,134,673 HYDRAULÍG APPARATUS Filed March 5, 1950 5 Sheets-Sheet 2 Oct. 25, 19318. G. J. RUSSELL 2,134,673 HYDRAULIC APPARATUS Filed March 5, 1950 \ ' 5 Sheets-Sheet 5 oct. 25, 193s. 2 1 3 46, 73 G. J. RUSSELL HYDRAULIC APPARATUS Filed »March 5, 193') 5 Sheets-Sheet 4 ugs-.sell Mp’ »572%217 Oct. 25, 19318. ` ' ' G. J. RUSSELL`v ` HYDRAULIC APPARATUS Filed March s, ‘1930 _' ' 2,134,673 l’ 5 sheets-sheet 5 §44 . 'è Patented oca-'25, 193s 2,134,673 UNITED STATES PATENT OFFICE HYDRAULIC APPARATUS George J. Russell, Waltham, Mass., assigner ofl l l(Tile-half to lEverett S. Emery, Lexington, Application March 5, 1930, Serial No. 433,491 ‘ 3 Claims. (Cl. 60-52) 'I'his invention relates to hydraulic means for system; and also to improve the construction and imparting a back and forth, intermittent, or re arrangement of parts of apparatus, of this char- - ciprocatery motion to a member and to means for acter. effecting such movements atldifferent rates of In the drawings: speed on the working and return strokes of Fig. 1 is a top plan view of a breaching ma- various machines such for example as on the cutting and return strokes of_ breaching ma- chine; , ` , 5 ‘ Fig. 2 is also a plan view of a portion of the chines. apparatus shown in Fig. 1, but showing the parts ' In many types ef machines itis advantageous"` to use one or more power cylinders for advancing and returning a tool or other instrumentality. A reversible or other type of pump may be pro- in different relative positions; . Fig. 3 is a longitudinal vertical section of the> 10 machine with the pilot withdrawn and the other v vided for supplying pressure ñuid to the cylinders parts arranged as lshown in Fig. 2; Fig. 4 is a section taken substantially along the and in such cases it is more economical to use-a line 4-4 of Fig. 1 with the parts arranged as pump having approximately the capacity re- shown in Fig. 2; quired to make the working stroke at the desired speed. However when this is done the pump,- due toits limited capacity, can only effect the return \ stroke at approximately> the same speed as the 20 working stroke. This procedure results in a considerable loss of time and -the desirability of speeding up the return stroke will be apparent. v To remedy this condition Without increasing the capacity of the pump over that vrequired for the working stroke, itis proposed to equip the, cylinders with pistons having unequal pressure ` areas on their opposite faces, the greater area » Í . Figs. 5, 6, and 7 are transverse vertical sections taken on substantially the same horizontal plane through the body of the control unit to show the parts in different relative positions, Figs. 5 and 6 showing diiïerent 'sections of the choke valve, 20 While the latter is shown in elevation in Fig. 7; Fig. 8 is a section taken substantially along the line 8-8 of Fig. 5; ` Fig. 9 is a section taken along the line 9--9 of Fig. 7 ;,„and _ 25 Fig. 10 is an elevational view of apparatus for reversinga pump. being effective on the return stroke, and to proThe features of this invention, Fig. 1, are i1 vide for by-passing ñuid around the piston en lustrated as embodied in a breaching machine of the general type disclosed in my prior Patent No. 30 the -return stroke. The delivery side of the pump is connected toboth ends of the cylinder during 1,431,437, issued January 22, 1924. and also in mv this return stroke and movement of the piston l copending applicationSerial No. 433,490, filed on is produced due to the difference in effective areas even date herewith (iSSlled November 21. 1933,’ on the opposite faces thereof. The piston then as Pat. No. 1,936,073). This machine COIIIDI‘ÍSeS acts as a pump to force iluid from one end of the a bed I0 which is supported on end pedestals Il cylinder through the by-pass to the other _end and I2 and is provided with transverse end mem of the cylinder. The volume delivered 'to the bers I3 and I4 and with longitudinal side members cylinder, by the combined ilow through the byl5 .and |'7- Intermediate the end members the pass and from the pump',- is so greatly increased bed is provided with transverse members I8', I9 and 2|, the latter being fitted with an external 40 that the return stroke is very' rapid. In cases where this system has been empmye'd it has been guide 22 which slidably receives and supports necessary to slow down the return stroke to a ‘ pieces 0f previously breached SÈOCk 23 in Which speed far below the maximum attainable speed the rear end of the breaching 19001 24 iS Supported in order to avoid damage to the apparatus or to During the broaching stroke a pilot 26, in the auxiliaries due to the high pressures and/or member I9, is advanced to the rightas shown in `velocities resulting from the combined new and Fia-3. dotted lines. tc engage the rear end cf the greatly increased volume. ` Objects of the present invention are to improve a system of this kind so that the return stroke can ' 15 30 ` 35 40 45 breach 24 to hold the latter stationary. 'I‘he DilOt iS COImeCted 130 the I’Od 271 0f a plunger 28 . Which is slidable in a cylindrical guide 29, this be made at greater speeds without damaging> or „otherwise interferingwith the operation “of the guide being supported on the transverse member 50 I8. The transverse member I9 carries an exter - apparatus or with auxiliaries associated with the nal cuide 3| which slidably receives the pilot 26 apparatus; to provide improved apparatus of this ' and red 2T fOr guiding and SUPPOl’ting the letter character for operating broaching machines; to during advance and withdrawal of lche pilet- A guide plate 30 is mounted on the guide 3|.slidably 55 55 provide improved broaching apparatus; to provide improved means for controlling apparatus of ‘ to receive the pilot. The external guide and guide this general class; to provide for reducing the plate function t0 keep the pilot Dl‘OperlY centered number of iittings required for a. system of this Withrespect to the rear end> of the breach. A kind; to provide hydraulic apparatus for these pitman 32, Fig. 3, is plvotally connected to the purposes and having an improved circulatory plunger -'M3 and _to 'a crank arm 33, the latter be- 00 « 2 ’ 2,134,073 ing fast on a shaft 34 which is supported in bear able delivery, reversible iiow pump 1|, Fig. 3, ings 88 (Fig. 1) carried by the frame. The under which is driven only in one direction by a suitable motor 12 through a coupling 13, reversal of flow side of the crank arm 88, as shown in Fig. 3 is in the form of a sector adapted to engage a rack 31 which is slidable longitudinally on the upper exterior surface of an auxiliary cylinder 88. Movement is imparted to the rack 81 by actuating the auxiliary piston 39 in the auxiliary cylinder, the piston rod 4| being connected to a depending 10 lug 42 formed on the end of the rack so as to oper ate the latter. The auxiliary cylinder is pro vided with ports 43 and 44 for admitting and dis charging pressure fiuid. ' The stock to be broached, Fig. 3, may be posi tioned manually but is vpreferably delivered through a chute 46 to a stock carrier or cross-head 41 when the latter is in its withdrawn position as shown in Fig. 1. The stock may be supported upon the stock carrier by means of brackets or 20 lugs (not shown) in the manner disclosed in my aforementioned prior patent, No. 1,481,437, or as disclosed in my application Serial No. 424,557, being eifected without reversing the _direction of rotation of the pump. The port 58, Fig. 4, in the rod end of each of the main _cylinders 52 is connected through the pipe 14, the T 15 and the pipe 11 to one of the ports of the pump 1|. The port 54 at the head end of each cylinder 52 is connected through 10 pipe 18 to the other port of the pump and it will be understood that when the pump is operating ' to denver aum through the connections 11, 1s one 14' to the port 58 the piston 5| will be displaced from right to left as shown in Fig. 4 and the cross 15 head 41 will be moved to advance stock over the broach, this being the working or cutting stroke of the machine. During this stroke fluid will be discharged from the port 54 through the con nection _18 to the pump 1|. After the completion 20 of this stroke the 110W will be reversed so that fluid is delivered through the connection ,18 to filed January 30, 1930 (issued -April 25, 1933, as the head end 54 of the cylinders 52 and fluid will Pat. No. 1905,505). The cross-head 41, Fig. 1, is be discharged from the rod end 56 of these cyl mounted for reciprocatory movement in guide inders. ' ways 48 disposed longitudinally along the sidey It will be observed that the eiiective areaÍ of members I5 and I1 and motion is imparted to the the rod end of the piston 5| is less than the ef cross-head, Figs. 1, 2, 4, ‘by the piston rods 48 fective area of the head end of this piston due to the space occupied by the piston rod 49. For which are connected to the cross-head and to pistons 5| operating in power cylinders 52. As good economy it' is desirable to keep the capacity 36 shown in Figs. 1 to 4 these cylinders are sup' of the pump as low as is consistent with good ported in the transverse end member I4 and in the intermediate transverse member 2|. The heads of the cylinders, Fig. 4, are connected byy performance and assuming that this pump has suñicient capacity only to advance the cross-head 41 at the desired rate of speed during the work tension rods 53 in a manner more fully illustrated ing‘stroke, it will be seen that when the same volume of fluid is delivered to the head end of the cylinder to return the cross-head this vol ume will only be capable of returning the cross head at a slower rate of speed than that at which it was advanced. For example if the capacity of 40 the pump were required to advance the cross head at a speed of approximately 29 feet per minute the pump, due to the larger volume and eifective area in the head end of the cylinder, might only be able to return the cross-head at a 45 speed of approximately 25 feet per minute. In order to conveniently and effectively accelerate this return stroke, concentrate the-control of the mechanism at a convenient point for operation and repair, and also reduce the amount of pip 50 ing, connections and valves therefor. a control in my aforementioned application, Serial No. 433,490 (Patent No. 1,936,073). 'These cylinders are provided with ports 54 and 58 for admitting and discharging- pressure ñuid for operating the 40 cross-head. - After the stock has been'positioned ~on- the cross-head 41 and before the latter is advanced, the pilot 26 is advanced to the rear end of broach to take the thrust of the cut during move ,45 ment of the stock over the broach. The front center 51 is advanced to engage the front end of the broach for properly centering and support ing the same. - This center, Fig. 3, is carried by a center-retaining member 58 which is cylindrical 50 in form and carries an exterior rib 58 which en Sages an interior shoulder in the cross-head 41 when the latter is in its withdrawn position as shown in Fig. 1. The center-retaining member 58 is supported for longitudinal movement in a 55 sleeve 6I carried by the end member I8 and held in fixed position therein by a bracket 62 aiflxed to the end memher. _The outer end of the cen ter-retaining member 58, Figs. 3, 1, is enlarged in the form of a plunger 88 which is slidably received in the counterbore 84 in the sleeve and this end of the center-retaining member also .has a longitudinal bore 86 in which a tubular member 81 is disposed. 'I'he outer end of the tube 81 is connected to the bracket 52 and to a 65 pipe connection 88 carried by this bracket. As fluid is admitted through the tube 51 the center retaining member 58 will be displaced to advance the center. The detailed construction and ar rangement of the parts of this front center is 70 further illustrated in my application Serial No. 424,559, flied January 30, 1930 (issued April 25. 1933, as Pat. No. 1,905,508). Pressure-fluid for -operating the main power cylinders- 52 as well _as auxiliary cylinder 88, Fles. 3. 4, and the front 75 center 51 is delivered by a constant speed, vari unit 88, Figs.~5, 6, 7, is interposed between the pump and the power cylinders 52; A connection ' 82` extends between this control unit and the port 58 at the rod end of the cylinder 52 and a con nection 88 also extends -between the control unit and the port 54 at the head end of the cylinder 52. As shown in Figs. 5, 6 and 7, this control unit has a delivery passage 84 which affords communication between the connection 83 and the connection 18 of the pump. The connection 14- of the pump also extends to this control unit. The control unit 88, Figs..5, 6, comprises a body formed preferably of an intermediate section 81 and end sections 88 and 89, the passage 84 being disposed wholly within the end section 88. The end section 88 has a delivery passage 9| extend ing therethrough, the ends of the passage being closed by plugs 82, 88 which are threaded therein. A valve ring 84 is threaded .into the passage against an interior shoulder 85 and provides a seat for the valve disk 81. A cylindrical wall 88 extends upwardly from the valve disk and is preferably formed integral therewith. A series 55 60 70 . of longitudinally disposed circumferentially 75 _ i 3 2,134,678. spaced slots |00 are formed in the wall 98 to per mit ñuid to flow freely through this wall. A valve cage 99 has its `cylindrical lower portion threaded into the upper end of the cylindrical wall 98 of the disk 91. Ports |0| are formed in the cylindrical base portion of the valve cage and a tubular section connects the base with a plunger |02 which operates in-a dash pot |03 formed in i the plug 92. The plunger |02 is provided with ports |04 and with a central bore |06 which slid ably receives the stem of the valve |01. The seat for this valve is formed on the upper side of the tion and afford communication between these passages and the passage 9| in this end section. ` 'I'he end member 88 is also provided with upper and lower ports |53, |54 which register with the adjacent ends'of the passages in the intermediate section and aiïord the communication between these passages and the passage 84 in the section 88. The adjacent surfaces of the end and inter mediatesections 81 to 89 have complementary interfltting projections |55 which assist in hold 10 ing the various passages in alignment. The end and intermediate sections may be secured to valve disk 91, the valve being normally held on ' gether in any approved manner, as by means of its seat by a spring |08 which is disposed about the valve stem and seats against the base of the ¿valve cage. i . bolts (not shown). ' ‘ A choke valve |56 is mounted upon the section 15 88 and comprises a body portion |51 which may A hollow cylindrical extension l|09 depends from be formed integral with this end section as shown. the lower side of the valve disk 91 and is reduced at its lower end to flt within a spring | l I, the up of the choke valve and a ~right angle passage |59 per end of which seats ' against the shoulder extends ~between the connection 4|58 and a port 20 formed on the cylindrical extension. 4Ports ||2 are formed in the walls of this extension and a port || 3 extends longitudinally through the end thereof for affording communication between the valve |01 and the passage 9|. An abutment A pipe connection -|58 extends into the body |51 |6| which affords communication between the passage 84 and the passage |59. 'I'his passage, Fig. 9, |59 is enlarged to provide a seat |62 for aone way valve comprising a spherical member |63 which is normally held on its seat by a coil 25 member ||4 serves as a'seat for the lower end of spring |64. This spring is mounted upon a pin `the spring ||| and has a cylindrical extension ||6 " |66 carried by a plug |61 which is threaded into disposed within the spring. This abutment mem the end of the passage |59. Another passage |68 ber is slidably received in a cylindrical recess I|1 extends from the connection |58 Vand has a re formed in the plug 93 and is supported in adjust stricted portion |69 for restricting‘the ñow be 30 ed positions in this recess by engagement with an tween the portV |6| and the connection |58. For adjusting screw ||8 threaded through the end of convenience of rmanufacture the passage |68 may the plug. A suitable number of gaskets ||9 are be drilled from the side of the body |51 and closed disposed between the head of the screw and the with a plug |1| as shown, the restricted portion L1) plug for preventing leakage at this point, and it being drilled from the passage 84. ` will be understood that upon adjustment of the The pipe connection |34 on the intermediate screw one or more of these gaskets may be added section extends to the port 43 at the head end or removed to regulate and control the pressure ' of the auxiliary cylinder 38 (Fig. 3) and the con of the'fluid which actuates the front center. nection |58 on the end section 88 extends to the The intermediate section 81 is provided with port 44 at the rod end of the auxiliary cylinder, 40 upper and lower transverse or-cross passages. |2| pressure fluid being supplied through these con and |22. The upper passage has annular recesses nections, for 'operating the auxiliary cylinder. |23, |24 formed adjacent the ends thereof and Pressure iiuid for operating the front center is a. shuttle valve |26 is disposed in the upper supplied through the passage 68 which is con passage for controlling the iìow of fluid there nected through the T 16 tothe connection 11 of through. This valve comprises a rod |21 having - the pump. ' oppositely disposed valve disks |28, |29 secured A fluid reservoir or supply tank |8| (Figs. 1 thereon by means of nuts |»3I which are threaded and 3) is supported upon the transverse mem upon the reduced end portions'of the rod and bers I8 and I9 of the bed plate and a connection with a plurality of short, radially extended wings |82 extends between the bottom of this supply 50 |3|A positioned thereon substantially 90° apart tank andthe upper passage |2| of the intermedi circumferentially of the rod to position and guide ate section of the control unit. This passage | 2| the rod in the passage |2|. Seats |32, |33 are also has a port |83 and a connection |84 extends i formed in the upper passage and are adapted to between this port and the pump for permitting receive the valve disks |28, |29 respectively. A iluid to flow by gravity from the supply tank to 55 pipe connection |34 extends into the annular re the pump, the supply tank being preferably open to the atmosphere. cess |23. ` ` ' The lower passage |22 is -preferably a straight Means are also provided for automatically re cylindrical passage having annular recesses dis versing the flow of the pump as the cross-head or posed at the ends thereof to receive the annular stock carrier reaches either end of its stroke. As 60 seats |36, |31 for a shuttle valve |38. This shut shown in Figs. '1 and 2 a rod |9| is mounted to tle valve has a hollow cylindrical body |39 which slide longitudinally in bearings |92 supported by is formed integral with a transverse end wall |4|. the frame. Collars |93, |94 are disposed adjacent This end Wall has a central port |42 and a. seat the ends of the rods and are preferably arranged |43 for a one way valve |44, this valve being nor to be adjustable longitudinally of the rod so thatV 65 mally held on its seat by a spring |46. An annu they may be heldin various positions. If desired lar member |41 is threaded into the end of'the set screws (not shown) may be provided for hold-cylindricalbody |39 to provide a seat for the ing these collars in selected positions. An abut spring |46 and this member |41 is also provided ment member |96, Figs. 1, 2, is mounted upon the with ports |48, |49 to permit ñuid to ñow freely cross-head 41 in aposition alternately to engage 70 through this portion of the valve body when the one of the collars as the cross-head approaches valve |44 is in open position. The end section the ends of its stroke. This Iengagement causes . '89 is provided with upper and lower ports |5|, |52, the rod to move longitudinally in its bearings which register with the adjacent -ends of the up per and lower passages-in the intermediate sec with the cross-head, the arrangement being such that> the rod is moved to the right as shown in 4 2,184,673 Flgs. 1, 2 and 3 when the cross-head is moved to piston 5| from right to left and causing the cross- v its withdrawn position and the rod is also moved _head 41 to advance the stock over the broach to the left as the cross-head ñnishes its working for the working stroke. As the cross-head ap stroke. A rack |91 (Fig. 10) is formed on the proaches the end of this working stroke the abut ment |96 (Fig. 1) will engage the collar |94 and move the rod |9| to reverse the flow through the mounted onV a shaft |99 which is rotatably sup- , pump. On this reversal of flow the connection 14 ported in the bracket 200 mounted upon the end becomes connected to the suction side of the pump member I3 of the' frame. An arm _20I, Fig. 3, is and hence will tend to draw ñuid out of the pas ñxedly connected to the shaft |99 and the outer sage 9I through ports ||2, ||3 lifting valve |01 end of this arm has a slot which iits over the rod and back to the pump through the chamber 9|“ 202, the arm being held pivotally thereon by and the connection 14. The connection 18 is now round faced nuts 203. In a similar manner the connected to the delivery side» of the pump and fluid passes through this connection into the pas longer arm of a bell-crank 204 is pivotally con 15 nected to the lower end of the rod 202 While the sage 84 of the control unit and out through the connection 83 to port 54 at the head end of the shorter arm of this bell-crank is pivotally con nected to a rod 206. This bell-crank is mounted cylinder 52. The pressure developed in the pas to pivot on the pedestal II. The rod 206 is also sage 84 in the control unit is effective to move pivotally connected to a _bell-crank 201 arranged the shuttle valve |38 from the position shown in Fig. 5 to the other end of the passage |22 as 20 to operate a control plunger 208. It will be under stood that when the rod |9| is moved to one of shown in Fig. 6. Fluid also passes from the pas its extremepositions the linkage just described sage 84 through the upper port I 53 to the an will be effective to reverse the flow in the pump nular chamber |24 where it is effective to move 1I and that when the rod is moved to the other the valve disk |29 onto its seat |33, thereby clos ’ of its extreme positions by engagement with the ing this end of the upper passage |2I. When the shuttle valve |38 has moved to the abutment |96 the sector |98 will be moved in the underside of thenrod |9I at the end thereof and is'engaged by a gear sector |98, the latter being io opposite'direction again to reverse the flow. In the operation of the apparatus with the parts position shown in Fig. 6, fluid is permitted to ñow from the delivery side of the pump through the arranged and shown as in Fig. 1 fluid is delivered by the pump through the connections 11 to the T 16 and from this T through the connection 68 to the interior of the center retaining member 58 to advance this member. The rib 59 on the center retaining member however is at this time in en gagement with an interior shoulder formed in the connection 18 and the passage |22 to the connec tion 82 which añords communication with the port 56 at the rod end of the cylinder 52. Pres sure iluid is thus delivered to ports at both ends of the main cylinder 52 but as the head end of the piston has a greater effective area than the rod end, the diiîerential pressure will be effective to move the piston from left to right as shown in cross-head 41 so that the center retaining mem ber 58 can not advance until the cross-head has first moved the stock to be breached on to the end of the broach. l Fluid is also delivered by the pump from the connection 11 through the T 16 and the connec tion 14 to the upper end or chamber 9|a of the passage 9| in the Icontrol unit (Fig. 6). When fluid ñrst enters this passage 9|a the valve 91 is held on its seat by the spring III and the ñuid is diverted through the port I_5I to the annular re cess or chamber |23 and th'e pressure of the fluid of this chamber> acting against the valve disk |28 of the shuttle valve |26 forces this disk against its seat to close this end of the upper passage I 2| . Fluid then ñows from the chamber |23 through the connection |34 and port 43 to the head end of the auxiliary cylinder 38 and moves the piston 39 from right to left as shown in Fig. 3. This move ment of the piston 39, due' to its connection with the rack 31, serves to rotate the crank arm 33 in Fig. 4 to return the cross-head 41 to the position shown in Fig. 1. As this movement of the piston is initiated iluid is forced out of the cylinder through the portl 56 and back through the con 40 nection 82 into the passage |22 and into the pas sage 84. It'will be seen therefore that during this stroke the rod side of the piston 5I acts as an auxiliary pump to force fluid through the con nections just poined out from one end of the cyl 45 inder to the other. At vthe same time that the piston is functioning in this manner to by-pass ñuid from one end of the cylinder to the other, the pump may be operating at capacity to deliver fluid into the passage 84 and into the head end of the cylinder. This arrangement makes avail .able a very large volume of ñuid for displacing the piston on its return stroke and it will be ap parent that the return stroke may be made very rapidly. In such cases it has been found that the cross 55 a clockwise direction to advance the pilot 26 into , head is returned in this manner with greater engagement with the end of the broach. By ad justing the tension on the spring III by means of the screw I`| 8 the pressure in the auxiliary cyl inder may be maintained at the proper value to advance the pilot at the desired rate of speed to engage the broach before the cross-head is moved. When the pressure in the upper end of the pas sage 9|*ì attains a predetermined value the valve disk 91 will be moved oiï its seat against the action ¿of the spring I I I and fluid will then flow from the connection 14 through the passages 9|“, 9|, and through the lower port |52 into the lower passage |22. On entering this passage the iiuid will move the shuttle valve |38 to the left as shown in Fig. 5 to close this end of the passage |22 and ñuid will then flow from the passage |22 through connec tion 82 to the port 56 (Fig. 4) at the rod end of the power cylinder 52, thereby displacing the speed than is required and furthermore the high pressures resulting from this combined flow and increased volume are always far in excess of 60 those to which the auxiliary cylinder and -piping should be subjected. The use of such high pres- „ sures in this auxiliary cylinder subjects the cyl inder, the piston and piping as well as the pilot operating mechanism to unnecessary strain and 65 wear. In many cases where it has been at tempted to use such pressures in the auxiliary cylinder the piping has been blown out. Occur rences of this kind'are avoided with the present apparatus by the arrangement of the choke valve |58. It will be seen` that when pressure ñuld is admitted to the choke valve |56 (Fig. 9) through the port I6I from the passage 84 the spherical member |63 will be forced on its seat- to close the passage |59 and iiow to the connection |58 75 2,134,673 leading to the port 44 will be retarded by the restricted passage |69. This assures that lluid at these higher pressures will be delivered through the connection |58 and the port 44 to the rod end of the _auxiliary cylinder at a permissible rate and hence the parts operated by this cylinder will function in their intended manner. It will also be seen that when th-e piston 39 of the aux iliary cylinder is moving from right to left as 10 shown in Fig. 3 the pressure of this fluid will move the spherical member |63 from its seat, Fig. 8, and normal flow will be permitted through the passage |59 and the port | 6| to the passage 84 and to the suction slide of the pump. In order further to assure that damage will 15 not be caused to the auxiliary cylinder or to the main cylinder 5| or any of the connections or parts operated by these cylinders, the one way relief valve |44 is adapted to'open at such pres 5 necting the delivery passages, a bleed passage through said shuttle valve; a shuttle valve in the upper cross passage closing it between the deliv ery passages when the flow is in the ñrst deliv ery passage, while opening the cross passage be tween the reservoir and the second delivery pas sage; the valve in the lower cross passage clos ing the same between the delivery passages to permit ñow from the ñrst delivery passage to the ñrst cylinder end; and upon flow reversal said 10 Valve in the upper cross passage closes the con nection between the delivery passages and con nects the ñrst delivery passage to the reservoir; and the valve in the lower cross passage opens connection between the second delivery passage 15 and the first end of the cylinder, which flow is, as well, to the cylinder end opposite to said first end; the bleed passage in the lower cross pas sage opening when the flow in this reverse direc tion attains predetermined pressure to permit 20' flow through the bleed passage to the ñrst de be bled throughv the shuttle valve |38 into the livery passage. 2. The combination with a power cylinder _and passage 9| and that the pressures therein will be eifective through the ports, H2, ||3 to raise the ' a reversible flow pump for supplying pressure 25 valve |01 from its seat, _thereby permitting the fluid to the cylinder, of a control unit compris 25 fluid to be returned to the suction side of the ing a body, means providing separate passages from opposite sides of the pump through said pump. Should the pressure of the fluid be de creased below the" value to which the valve |44 body to opposite ends of the cylinder, said body . is set to open it will be apparent that .this valve having a passage means connecting said separate passages, a shuttle valve for controlling the ilow 30 30 will again close. . The function‘of the port |83 in the shuttle through said passage means forclosingone of 20 sures as are considered proper. It will be seen from Fig. 7 that when this valve opens fluid may valve |26 is to keep the inlet of the pump sub merged through connection |84 (Fig. 3) at all times so that the pump may be supplied with 35 fluid from the supply tank |8|. It will be ap parent that fluid is permitted to flow by gravity from the supply tank through the connection |82 into the‘upper passage |2| and out through the port |83 and through the connection |84 to the pump to compensate for leakage and for varia tion in the quantity ofoil required in the system. 'I‘he shuttle valve |26 is so arranged that it is always open to alford communication with which said separate pasages between the pump and the passage means, and pressure-responsive means carried by the shuttle valve for bleeding iluid from the passage means to said separate passage. 35 3. A control unit for connection between a re versible flow pump, a fluid reservoir and a power cylinder, said unit comprising a body having de livery passages through it for connection between opposite sides of the pump and opposite ends of 40 the cylinder, and having a supply passage for connection between the lluid reservoir and the pump, an upper cross passage in the body andv ever of the passages 14 or 18 happens at that between the delivery passages constituting. said rparticular time to be connected to the suction connection, and a shuttle valve in said cross pas 45 sage operable by the ñuid pressure in one of the By arranging the various connections and delivery passages to close said passage to the‘res valves in the control unit 86 it is possible greatly ervoir; and a lower cross passage between said de to reduce the number of ñttings required in a ' livery passages with a shuttle valve‘ therein op erable to permit pressure fluid ilow from one of 50 system of this general character and also to cen said delivery passages to one end of the cylinder tralize the various instrumentalities which con trol the system. In one particular instance the and also, on reversal, flow from the other deliv number of fittings required were reduced by this ery passages to both ends of the cylinder sirnul arrangement from approximately 45 or 50 to 17. taneously, and subsequently ñow from one cyl It will also be seen that by forming the body of inder end through said cross passage and through 55 55 side of the pump. ` - and 89 the various passages may readily be said delivery passage to the opposite cylinder end; said body having auxiliary passages leading formed by relatively simple manufacturing op from each of the delivery passages for connec the control unit 86 of separable sections 61, 88 tion to the opposite ends of an auxiliary fluid cylinder, one of said auxiliary passages compris 60 ing a plurality of ducts of diiïerent sizes, pres sure responsive means for normally closing the I claim: 1. The combination with a pressure -cylinder larger duct, thus restricting the flow through the having a piston, and a constant speed, reversible smaller duct, and to the auxiliary fluid cylinder, 65 flow pump, and a pressure iiuid reservoir, of a . the pressure responsive means being operable to 65 control unit between and connecting the pump provide for normal ñow from the auxiliary ñuid cylinder; and means for closing one of the de and cylinder and having a body, separate deliv ery passages from opposite sides of the pump livery passages until the pressure in the auxil through the body to opposite cylinder ends; an iary passage associated therewith attains a pre determined value. upper cross passage between the delivery pas 70 70 sages connected also with the reservoir; a lower erations and the various valves and connections 60 may easily be assembled in operative positions and are readily accessible for adjustment. cross passage having a shuttle valve and con GEORGE J. RUSSELL.'