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_ Aug. 13, 1946., H. A. KNOX l ¿405,52 CLUTCH Filed MarchB, 41944 - 2 Sheets-Sheet 1 Aug. 13, 1946.. H. A. KNOX I ' @2,405,582Í CLUTCH Filed March s, 1944 V ‘ 2- sheets-sheet 2 Figa Patented Aug. 13,1946 2,405,582 UNITED STATES PATENT OFFICE 2,405,582 ~ CLUTCH Harry A. Knox, Washington, D. C. Application March 8, 1944, Serial No. 525,511 17 Claims. l (Cl. 192-68) (Granted under the act of March V3, 1883, asV amended April 30, 1928; 370 O. G. 757) 1 2 The invention described herein may be manu factured and used by or for the Goverment for current war. The enlargement of springs in usual locations to alîord the necessary clutch governmental purposes without the payment to pressure, and the multiplication of discs and me of any royalty thereon. clutch surfaces have reached boundaries of prac The invention relates to power transmission CIS t-icability, without a satisfactory solution of the clutches, and has for an object to effect improve problem. The use of more than one disc is ob ment in a disc clutch operated through an axially jectionable because of the greater longitudinal slidable throwout member. space required and also the added machine cp The invention aims specially to improve con erations, fitting and assembly operations, and nections between a sliding sleeve and a presser 10 added materials. Sliding and keying or splin plate on a rotative member whereby friction ele ing of the multiple discs on both driving and ments of respective rotating members may be driven members is a serious objection. The cl-amped together to form the clutch connection. greater pressures required where a single disc is A further important purpose is to offer an employed of moderate diameter has been an in improved construction for operating the presser plate to attain high clutching eii'iciency within a moderate space. surmountable difficulty, where the limitations of space, economy in material and reasonable ease of assembly are satisfied; and it is one >of the most important motives in this invention to en vention to present novel means for amplifying able the production of a single disc clutch and the force applied through a spring element while 20 an amply adequate pressure applying means to involving only a moderate extent of movement clamp the disc to relatively rotating parts so as of the spring element. to transmit the high torque involved in tank It is well appreciated that one of the most im power plants, and at the same time gain marked portant objects in clutches for power transmis advantages and improvement in compactness, sions between internal combustion motors and 25 eñiciency, economy of manufacture and ease of final drive in motor vehicles is economy of space, operation and repair. especially longitudinally of the axis of rotation It is a special aim of the invention to provide of the driving and driven members, or longitudi for a liberal clearance of opposed clutch faces nally of the axes of the gearing of speed-chang at the same time that a high pressure spring ing transmission; and ordinarily all of the axes 30 action is provided for, enabling operation of the indicated are laid in the same direction, making device by a foot pedal with moderate effort, yet the reduction of space required for the clutch using a small and compact readily assembled still more important. spring device. In the production of military material there A specific end in view is to present a novel are several factors making this attainment para 35 assembly of clutch operating connection of high mount. First, all possible space is desired with leverage value so constructed and arranged as to in the length of the Vehicle for many auxiliaries, be affected in a minimum degree by centrifugal second, the running gear is in many cases short force. ` coupled, and to this is often added a four-wheel Another important attainment is the presenta drive making further requirement for such 40 tion of a' construction having the foregoing ad It is a specially important object of the in economy of space. Recently the use of radial airplane-type mo tors, especially in tanks, has put a further pre mium on space, because of the size of these mo vantages, yet which is adapted to be produced with a minimum of difficulty in manufacture, and assembled manually with few fastening de vices, and a minimum requirement for the use tors, and in tanks, the limitations imposed 45 of tools. encompass as small a space therewith as possible It is a further object to añord a novel toggle construction and operating means therefor en by the use of armor (making it necessary to v and yet protect the power plant, driver and abling the application of the high pressures to large crew) and the multiplication of gun units the clutch which may be expected from the use radio equipment and other elements have put a 50 of such a device 'in a simple and rugged con barrier in the way of amplifying conventional struction yet one light in weight compared to clutch designs to carry the prodigious loads in the proportions of conventional clutch construc volved by the great mass of these vehicles and tion and the high degree of force transmitted. the greatly enlarged power output required to A further important attainment in view is to move them at the high speeds demanded in the 55 enable ready access to all parts of the clutch op 2,405,582 4 3 erating connections for replacement or repair working upon the hub I5 closely adjacent the with a good working space therearound for base of the base plate I5. The bore of the driven hub is reduced rearwardly of the hub i6 in aline ment with the nut I8, a roller bearing assembly 21 being fitted between the nut and driven hub at this part. The motor shaft terminates at the nut in this instance permitting a further sub stantial reduction in diameter of the hub 25 as at 28 where it is extended as a hollow splined manipulation of convenient tools. It is also sought to oiïer a construction which will have great value for production in smaller sizes, for incorporation in small passenger cars and trucks. Additional objects, advantages and features of invention reside in the construction, ar rangement and combination of parts involved inH the embodiment of the invention, as will appear or be understood from the following description . coupling hub, a grease injection hole 29 being provided therethrough for conventional grease or oil supply fittings. Immediately adjacent the end Y or the hub lâ a radial port 30 is formed through and accompanying drawings, wherein: the hub 2E for passage of lubricant from within Fig. 1 is a section elevation of the rear side of a clutch constructed in accordance with my in- the hub to a throwout sleeve felt to be described. A concentric annular recess 3l is formed in the forward face of the disc near its axial bore, Vention; Fig. 2 is a vertical section on the line 2--2 of the inner side» thereof having an overhang 32 to throw off lubricant escaping from the bearing 26 and the base plate I5 has an inwardly inclined annular rib. 33 extended rearwardly into there cess 31, forming a gutter 34 to receive lubricant thrown oli by the overhang 32, drain holes 3.5. leading from the bottom ofv the. gutter forward through the plate l5 and inclined away fromy the shaft, so. as to discharge oil forwardly from; the Fig. 1; Fig. 3 is a fragmentary section on the line 3-3 of Fig. l; Fig". 4 is a` fragmentary section on the line #-4, of Fig. 1; rl‘he Figures 1 _and 2V are drawn approximately onefhalf of the full size of apparatusheretofore constructed.. for tank “Se Reierring. to the drawings, there is shown. the, gutter. rear, extremity of. a motor shaft lil, or prime mover, haying a tapered. conical portion ll a A presser plate 35 is mounted rearwardly of the disc for translative axial> movement toward and away from the disc and base plate. This presser plate consists of a thick planiform annular body coextensive with the zone 24 of the disc and having a medial concentric stiffening rib 3_1, and four radial support lugs 3B. spaced to aline with distance forwardly, ending rearwardly ata cylinf. drical part l2 which extends over a substantial distance rearwardly from the part ll, a splined part I3., and. a. relieved tenori t4 is formed on the extremity of the shaft, the outer or rear part which isexternally threaded to. receive a forcing mit. llito be referredto. A. Dlaníform circular clutch base plate i5 is provided, constituting the driving member of the the lugs 26 respectively. The lugs 2l! and 38 each includes an angle of about 30 degrees, so as t0` each receive therethrough three heavy assembly and presser plate centering bolts 3,9 securing clutch and having a hubY I6 bored and splined brackets ¿lil vto the rear facesof the lugs 2n. The to fitthe splined cylindrical part 1.3, of the shaft, with a forward _flare lâ’ fitting the tapered. part 40 brackets project inwardly behind the presser plate and are also inclined longitudinally rear I_l. 0f the shaft. The hub. stops short of the» ward. At their inner and. rearward parts they2 threaded part of the, tenori and; is. conically re-Í are formed with integral radially bored and split lieved interiorly to receive a wedgecollar I1 slide pin holding clamp collars 4i, in which are in able on the forward smooth. part of the tenori and fitted to the conical end of the bore in the 45 serted enlarged. cylindrical pin bodies ¿l2v exposed at the outer sides of the collars and slotted for. hub. It is pressed forward by a forcing nut i8 screwed onthe extremity of the tenon, whereby rotation by a screw driver or other tool at times, the> hub is. likewise forced. on tothe conical. part as-will be explained» thev collars are splitat` theirv outer- sides in a plane parallel' to that ofthe ilv of~ the shaft lil, witha greater extent of sup-». 50 plate l5, and- the outer rearward spring arm ¿Lil port longitudinally. than afforded by thering. thus formed is extended and` apertured as usual in such clamps, to receive therethrough a clamp bolt 44, screwed into a corresponding threaded hole in the body ofA the bracket under the arm. 55 The pin body 42 has an- eccentric pivot stud 45 ‘I_‘henut .Ik is formed with.I an` externalA hard cylindrical face. to.. serve as a rear bearing- for the driven member as will be described. Theinut has a. swivel connection with. the collar so- that un screwing of thenut willdraw out the collar. extended longitudinally thereof and inward onv a The base plate is of- substantial mass so that itmay serve as a flywheel, and includes-a` periph eral cylindrical rearward extension or flangeA i9 concentric with the> shaft. It has» at its rear'edge rad-ial axis, to receive one member- of a toggle to be described. Each of the bolts 35 is in threaded eng-age a series of four equally spaced lugs 2B- projected 60 ment with the lug 2G thereat, but freely- revoluble in the base of the bracket 40, and at its forward inwardly toward the> shaft parallel to the plate I5. extremity is formed with a slightly reduced - smooth cylindrical guide pin portion 45 extended forwardlybeyond the lug 20 and engaged snuglyV A drivenv member 2l is» revolubl'e onY the hub and nut, consisting of a circular~ disc 2-2 of a radius less than that of theinner edges of the 65 andslidably through holes in the lugs 38 of the presser plateV so as to support the latter'slidably. lugs 2.0 so that it'may be moved axially into and On the rear side of the presser plate there are out of operative position. The disc has opposite quadriradiate raised bearings Sii, extending part facings 23 of suitable friction> material». ly across t-he rear face of the presser plate and` The disc body is planiform over an outer an inwardly thereof a distance, the plate having nular zone 24 and throughout on its forward sur corresponding inward strengthening extensions face, but is progressively thickened from the Y 4_1 thereunder, these stop outwardly of the hub The disc has an integral rearwardly» extended hub 25, its interior bore being~ relieved at the forward» end-to» accommodate roller bearings 28> substantially of rib portions radially'bored to zone 24 inwardly in a rearward direction. 25 a substantial'distance. The bearings consist form a semicylindrical bearing surface 48; a slot' 5 2,405,582, 49'being formed through one side throughout the’ abler inwardly freely when the shaft is away from length of the bore. One side 5I of the slot 49 its bearing. A U-shaped yoke 10 has its arms 1| in a clockwise direction is tangent to the bearing apertured and engaged revolubly on the stud 61. face 48 and in a plane parallel to the axis of the The head l2 of this yoke is apertured to fit slidably hub while the opposite side 52 of the slot is paral Ul around the rod, and the latter has a threaded lel to the side 5l and located approximately 215 tenon at its extremity between the arms of the degrees from the radius of the tangent mentioned, yoke, on which a square nut 'I3 is screwed, ñtted so that the clearance in the mouth of the slot is snugly between the arms 'H by which it is held correspondingly and substantially less than the against rotation on the rod after assembly. The diametrical measurement of the bore. nut constitutes a limiting means to the rearward io A crank shaft 53 is provided fitted revolubly in movement of the yoke head 1I on the rod, and the bearing and extending beyond each end there may be adjusted if desired by unscrewing and re of. This shaft is formed with a flat 54 through moving the stud 6T then rotating the yoke and nut out its length parallel to the axis of the shaft and together in the proper direction. subtending an angle of approximately 90 degrees 15 The head 69 affords a shoulder 'M around the more or lless on the cylindrical surface of the rod next the wrist 59, and between this shoulder shaft. As a result the measurement on a line and the head of the yoke 10 a multiplicity of normal to the face 54 through the axis of the Belleville spring washers 'l5 are confined, slid shaft to its periphery is less than the width of ably engaged on the rod and arranged in pairs the slot and when the shaft is presented at the 20 with their concave faces opposed. These washers slot parallel to the bearing and with the ñat ad are in such number that when the throwout sleeve jacent the side 52 the shaft may be moved lat is at its rear limit the washers are moderately erally through the slot to a `bearing in the bore. confined, and when the sleeve is forward to dead When then rotated to its approximate operative center relation as in Fig. l the washers are com position as in Fig. 3, with the flat 55 extended pressed to a desired maximum. The full extent across the slot, the shaft is retained firmly in of this movement need not be more than one place. The principal loads communicated to- the eighth inch in a heavy duty clutch, although this shaft are sustained by the inner part of the bear may be increased by decreasing the number of ing and near the side 52 of the slot. The shaft washers and properly proportioning the latter to is formed with two integral upper and lower arms give the desired maximum pressureforce .under or levers 55-55 of short radius, each on the same the extent of compression involved when the link radial' plane of thev shaft, extending obliquely age is in dead center position. across the plane of the flat 54. The upper arm 55 With the linkage between the throwout sîleeve is formed with an enlarged base 51, providing a and crank shaft in dead center position and the ‘ shoulder 58 resting against the inner end of the 35 presser plate 3S fully engaged against the disc bearing 50. and facing, the member 42 is preferably so ad The upper crank arm is provided with a wrist ¿usted initially that the link lever SI and crank pin 59 fixed thereon and extended upwardly on lever 55 are. short of dead center position to the an axis parallel to the projected axis of the shaft extent of between live and ten degrees of an 53, while the lower arm 55 is provided with a gular movement on their axes. 'I‘his allows for: similar pin 6D, also extended upward, that is, to a considerable further operation of the toggle ward the clutch axis. linkage when the facings become somewhat worn, ' A compression toggle lever link 6I is fitted on by expansion or extension of the linkage through the stud 45 (retained by washer and cotter Eil’) action of the Belleville washers, which, while the and wrist pin E5, and the aggregate of the radii parts remain in dead center relation will never of the arm 55 and link 6l is greater than the theless effect a further thrust upon the inner distance between the axes of the shaft 53 and crank arm 55, so as to operate the‘toggle through stud 45.. This last named distance is variable a further movement than initially set for. Also, by rotating the pin body 42, .when the clamp 4l at dead center position of the linkage to the is `released, throwing the stud 45 toward or from 50 sleeve, and initial adjustment of the togglel de thepresser plate. It is apparent that the arm vice, the crank arm 55 is somewhat inclined at 5`5'and link 6I are capable of functioning as toggle its outer part toward the axis of the sleeve. levers by movement toward their dead center rela In order to support the sliding junction of the tion. . > yoke 10 and rod E8, the nuts 'i3 are each pro ‘ On the hub 25 there is slidable a throwout 55 vided with longitudinally extended rest arms 16 sleeve 62 at the rear end of which a channel B3 at opposite sides, adjacent and against respec is formed exteriorly, in which a throwout rin’g tive arms 'il of the yoke. These arms are as wide ’54 is revoluble, operated conventionally by a usual as the arms of the yoke and have longitudinal yoke not shown to reciprocate the sleeve as de guide slots 'H open through their outer ends and sired. At its forward end four thrust arms 65 are 60 receiving the body portion of the stud 6'! therein formed or mounted on the sleeve extending nearly for rotationwhen the stud is screwed or un tangent to the sleeve in a counterclockwise Edi screwed, but, more important for sliding move rection and formed with respective knuckles 55 ment of the stud in the slots as the yoke 'lf3 com in which there are ñxed respective pivot bolt studs presses the washers 'I5 or withdraws oppositely 'il> on axes parallel to the respective shafts 53 65 on the rod 68. When the washers expand the .nextY to the bases of the arms 65. A thrust link outer end of the rod is thus supported slidingly connection is formed between the studs 6'! and on the stud independently of the yoke lil, pre respective adjacent wrist pins 59, so proportioned venting binding or excessive wear of the latter vthat at the forward position of the sleeve 62, the against the rod. wrist pin and stud may lie in the same plane 70 In the use of this construction, the toggle de normal to the axis of the sleeve-in other words, vice will be considered broadly as including con in dead center relation. The linkage in the pres necting portions 45-56-55--6L the linkage 61 ent instance consists of a rod 68 having a'trans to 15, the shaft 53, and the crank 55. The'mech versely bored head B9 receiving the wrist pin 59 anism being assembled as described, the released sliidably'and revolubly therethrough and remov 75 position of the parts will be substantially as indi 2,405,582 7 cated in dotted lines in Fig. 4. The Belleville washer unit or linkage will be fully extended so that. the head 12 of the yoke 1G wil be pressed against the nut 13, and the stud 61 will be at the rear limit of its movement, in full size about one and three quarter inches from dead center posi 8 wrist B0, so as to permit the latter‘to be swung'to position for clearing the shaft from the bearing. While I have disclosed this invention with par ticularity in its best construction knownl to me, it will nevertheless be understood thatÍ this. is purely exemplary, and that changes in construc tion, arrangement and combination of parts, sub tion. The inner crank arm 55 will be inclined stitution of materials, and equivalents mechani inwardly toward the axis ofthe sleeve to a maxi cal and otherwise, may be made therein Without mum and the toggle device portion ¿l5-55-60 departing from the spirit of the invention as set Bi will be broken from dead center position fur forth in the appended claims, wherein I claim: ther than shown in Fig. 3 to the extent. involved l. in a clutch of the character described, a by the dotted position of the inner crank arm rotary driving member and a coaxial rotary 55 in> relation to its full line position in Fig. 4. driven member on a main axis axially movable This position of the toggle will have resulted in toward and away from the driving member, an drawing the shaft 53 rearwardly and with it the axially movable presser plate ñxed angularly with presser plate 36, slidingly on the stud ends 46 the driving member, a toggle device having one of the bolts 39, and freeing the disc 22. member element based on the presser plate and On operation of the pedal or other levers cus the other on the driving member on toggle axes tomarily employed to operate the sleeve, the lat substantially radial to the main axis, one mem ter is moved slidingly forward, applying pressure :ber element thereof having an operating rocker throughout the linkage 81 to 15 to the crank arms 55 so as to move these outward and swing shaft extended inwardly to an are- of' rotation ing the toggle device portion 56-6û-6i toward on` said main axis lof less radius than that of the toggle and having a crank at its inner part, dead center position. In the early part of this operation, relatively small opposition to compres a slide axially movable on and angularly fixed with the driving member, and a linkage con sion will be manifest and the movement will re quire only moderate force despite the low advan nected between the slide and crank at an angle tage in the leverage involved. As the resistance to the latter and at an angle to the path of rela of the washers increases so does the advantage tive axial movement of its connection with the in leverage, so that moderate effort will still effect 30 slide, and means to operate the slide, the movement required under increasing pres A2. The structure of claim 1 in which said link sure applied at the clutch faces. The operation age is constructed and mounted on said slide for of the clutch pedal as last described may be by movement relatively thereto in a plane parallel spring action or manual, and may include means to the said main axis. `to limit forward. movement 1 of the throwout sleeve, as in my Patent Number 2,380,971, issued 3. The structure of claim 1 in which said link age is constructed and connected to said slide August .7, 1945. at a, distance radially outward from said main Among the advantages of my invention in ad axis adjacent the radius of the arc of rotation of dition to those first mentioned, are the small the crank around the main axis and spaced an number of fastenings such as pins and nuts or 40 gularly from the crank in relation to said main screw threaded or other fastenings of or between axis a distance equal to the length of the linkage, operative parts requiring tools or tooling in as whereby a dead center leverage may be applied sembly, or disassembly of the mechanism. Thus, with a minimum of elements o-f centrifugal force centrifugal force will hold the link lever 6| in included. operative position so that only a small cotter pin ëi. The structure of claim 1 in which said shaftv BI’ is sufficient, required only during assembly is radial, and the plane of operation of the tog and when the parts are at rest. Likewise the con gle is tangent to the path of translative motion nection of the linkage with the wrist 59 requires of the toggle around the said main axis.V no fastening at all, the clearance between the 5. The structure of claim 1 in which said shaft wrist and sleeve being insuflicient for detach 50 is radial, said toggle having its outer pivots> on ment of the head 59, and the latter being thrust axes radial to said main axis, means to adjust the spacing of said pivots, said crank being movable home on the wrist by centrifugal force during with said shaft over a path having its mean ad operation. The assembly and disassembly o-f the jacent a radialplane of said main axis and said extensiblelinkage also may be effected manually without a fixed fastening, the nut 'i3 being un 55 linkage is of aV length to lie on dead center be tween its connection with the sleeve and the screWab-le Lby rotating the yoke» 'lil after dismount crank. ' ing, The shaft 53 is removable without Vtools 6. The structure of claim 1 in which a bearing after dismounting the linkage from the stud Bl, by extracting the Cotter pin 6i', litfing off the for said shaft is formed on said presser member link 6I, and after rotating the shaft clockwise 60 at its rearv side, the said bearing having a longi as viewed in Fig. 3 to `bring the flat 5G parallel tudinal slot whose diameter is of a width less than the diameter of said bearing opening there to the tangent side 5| of the bearing slot beside from toward the rear,V one side of said slot being the shaft. At this last named position of the shaft the linkage may be lifted from the inner wrist 59, manually. The linkage may be disas sembled and assembled manually, since the range of movement of the nut i5 on the threaded ten oned end of the rod is sufficient to relieve the discs of compression in outward direction and to effect full compression of the discs when screwed inward to the operative position of the nut previ ously described. The wall of the bearing 50 is exteriorly relieved (as shown in Figure 3') at one side at itsouter end, adjacent the side 52 of the bearing slot, in line with the path of the outer tangent to the said bearing, the said shaft hav ing a ñat‘ disposed normally across the said slot, the transverse dimension of the shaft on a line through its axis normal' to the said flat being less that the width of the slot. 7. The structure of claim l in which the press er plate has a bearing for said shaft extending generally radially, said shaft being revoluble therein and having a shoulder at its inner part against the bearing to transmit thereto centrif ugal force evolved on rotation ofthe shaft trans latively aroundv said main axis, a wristv pin' 9 2,405,582 mounted in said crank and extending toward said main axis, said linkage including a terminal member set slidably and revolubly on the wrist pin and having an applied position extending at a tangent 'to the path of said wrist around said main axis, said slide having an offset bearing for l2. The structure of claim 11 in which means is ,included to adjust the pivot of said toggle link on the bracket toward and away from the driv ing plate, and in which said last named link is extensible, and elastic expansive means coact ing between the end portion of the link to main the outer end of the linkage. _ tain a predetermined transmission of pressure 8. A linkage for the uses described consisting between the slide and said crank. of a pressure transmitting member, a pressure 13. The construction in claim i2 wherein the applying member having angular limited con last named link includes a rod having a head vergent movement in relation thereto a link rod 10 revolubly mounted on the crank, a U-shaped pivoted on the transmitting member, a pivot yoke having an apertured head slidable on the yoke on the pressure applying member and slid rod, a stud on the respective thrust arm engaged able on the rod, a nut having threaded engage through the arms of the yoke the rod having a ment with the extremity of the rod outwardly of threaded extremity' extended between said arms 15 the yoke to limit outward movement of the yoke of the yoke a nut screwed on the rod and held on the rod, and a multiplicityof Belleville wash between the arms, and aprotractile spring de ers carried by said rod between said yoke and vice engaged loosely around the rod and conñned said transmitting member and adapted to trans between the heads or the rod and yoke. mit the pressure applied by Said pressure apply 14. A clutch comprising clutch members rela ing member from said yoke to said transmitting 20 tively revoluble on a main axis, a toggle device, member. 9. The structure of claim 8 in which said yoke an element of which is mounted on one clutch member, and having pushing connection with the other and having its members pivoted on axes approximately radial with respect tc said proportioned so that at the pressure applying 25 main axis, an eccentric linked to the toggle for has parts extending in close iitting engagement with said nut and beyond, and the whole being limit of movement of the pressure applying adjustment of the same, a throwout member member said yoke will be clear of the nut. slidable relative to and fixed angularly relative l0. In a clutch a rotating driving plate, a con to the toggle on said main axis, a pivot member centric rotatable driven member of less diame on and ñxed axially with the throwo-ut member ter, an axially movable presser plate rearwardly 30 closely adjacent a tangent of the arc of move of the driven member, the driving plate having ment of the toggle device around said main axis outer rearwardly extended parts and inwardly and an elastic extensible shaft connected be extended ears thereon, said presser plate having tween the said eccentric and said pivot member corresponding ears adapted to pass inwardly be on the throwout and having a minimum length tween the ñrst named ears under relative axial 35 equal to the distance between the eccentric and translative movement of the presser plate and pivot member when the throwout member is in to lie in registry with the ñrst named ears with position with the eccentric and pivot member in in said rearwardly extended parts, brackets a plane normal to said main axis, constituting a mounted adjacent the first named ears, pressure dead center relation. transmitting means mounted upon said brackets l5. The structure of claim 8 in which said and engageable with the presser plate, and yoke has parts extended beside said nut and be headed bolt members having threaded engage yond, the whole being proportioned so that at ment in the ñrst named ears and slidable in the the pressure applying limit of movement of the brackets and through the second named ears in pressure applying member said yoke will be off supporting engagement therewith and having 45 bearing at the nut, said nut having a longitudi their heads in clamping engagement against said nal extension slidingly engaged with the pressure brackets. applying member for support of the rod end. 11. In a clutch, a rotating driving plate, a 16. The structure of claim 1 in which an op concentric rotatable driven member of less di erating crank is formed on said rocker shaft, said ameter, an axially movable concentric presser 50 linkage being pivoted on said slide and the end plate ñxed angularly with the driving plate of said crank, said pivot on the slide being angu rearwardly of the driven member constructed to larly spaced from the axis of the rocker shaft clamp the driven member against the driving around the axis of the clutch and said linkage plate. said driving plate having rearwardly ex being of a length to permit movement of the tended parts, inwardly extended brackets there 55 slide to position both pivots of said linkage in a on spaced rearwardly of the presser plate, radial common plane normal to the main axis. bearings adjacent said brackets, a shaft revol 17. The structure of claim l in which an op uble in each said bearing having a rearwardly erating crank is formed on said rocker shaft, extended toggle arm, a toggle link pivoted on the said linkage being pivoted on said slide and the adjacent bracket and pivoted to the toggle arm, 60 end of said crank, said pivot on the slide being a crank on the shaft inwardly of the toggle ex angularly spaced from the axis of the rocker tended in the same general direction as said tog shaft around the axis of the clutch and said link gle arm, a link extended therefrom having an age being of a length to permit movement of the operated position transverse to a radial plane slide to position both pivots of said linkage in a of said driving plate, a coaxial slide axially mov 65 common plane normal to the main axis, said able on the axis of the driving plate and a thrust linkage being movable to and beyond a dead cen arm for each last named link on the slide pivot ter relation to its connections with the slide and ally connected to the link and movable rearward crank whereby radial components of force in ly with the connected end of the link from said the action kof the clutch are minimized. operated position, and means to operate the slide. HARRY A. KNOX.