Abstract:
A manually operable clutch assembly-disassembly tool that is utilized with multiple plate, fluid-actuated-type clutches wherein it is necessary to compress a piston return spring so as to permit either the insertion or removal of a snap ring in assembling and disassembling of the clutch, with the tool being affixable to the clutch and having an inner annular member that is axially displaceable, via displacement means, relative to an outer annular member attached to the clutch drum, thereby compressing the piston return spring and permitting insertion or removal of the snap ring.

Description:
BACKGROUND OF THE INVENTION 
     1. Field Of The Invention 
     The field of art to which this invention pertains is that of multiple plate fluid-pressure actuated type of clutches used in power-shift transmissions, and, more particularly, to a tool used for compressing piston return springs so as to permit the ready manual insertion or removal of a snap ring that secures the piston return spring retainer cup. 
     2. Description Of The Prior Art 
     Constant-mesh powershift transmissions of the type shown, for example, in prior U.S. Pat. No. 3,893,345 generally utilize multiple plate, fluid-actuated clutches. These clutches generally include an internally splined drum affixed to a first rotatable transmission member, an externally splined hub affixed to a second rotatable transmission member and a plurality of interleaved friction plates splined alternately to the hub and drum. The friction plates are confined between an annular end plate and a fluid pressure actuated piston which serves to press the friction plates together, thereby connecting the hub and drum for conjoint rotation in a manner well known in the art. Generally, the piston is biased in the direction away from the friction plates via a piston return spring confined between the piston and an annular spring retainer cup that is secured against axial movement by a snap ring located in a snap ring groove in the first rotatable transmission member. 
     The force of the clutch return spring, which is generally from 100 to 150 pounds, must be overcome in order to install the retainer cup snap ring. Prior art assembly or disassembly of this type of fluid actuated type clutch involves removing the entire clutch from the transmission and then, after further removal of the interleaved friction plates, inserting the clutch assembly onto an arbor press and compressing the spring by the use of a cylindrical sleeve which has an opening through which a snap ring removal tool can be manually inserted for removing, or in the case of assembly, inserting the snap ring. 
     Since it is a common practice to service these transmissions and clutches in the field, arbor presses are not always readily available. In addition, in some instances, it would be possible to service the clutch without removing it from the transmission if it were possible to add or remove the snap ring and clutch piston return spring without the use of an arbor press. 
     SUMMARY OF THE INVENTION 
     The clutch assembly-disassembly tool of this invention solves the previously noted problems of ready serviceability in that the tool is readily portable; can be used in combination with merely a wrench; and can be used on the clutch after it is removed from the transmission, as well as being usable, in some instances, without removing the clutch from the transmission itself. 
     In summary, the clutch assembly-disassembly tool of this invention includes an outer annular member that has external splines and which is adapted to fit within and intermesh with the internally splined clutch drum. An externally expanding split retainer ring is adapted to fit within a retainer ring groove of the clutch drum and restrains the outer annular member against axial movement out of the drum. For ease of operation, the adjacent end portions of the split retainer ring are provided with a pair of parallel and axially extending grip portions so as to permit ready manual manipulation thereof. Fitting within the outer annular member is an inner annular member that is adapted to seat on the spring retainer cup and means are provided for displacing the inner annular member axially inwardly relative to the outer annular member so as to thereby compress and axially displace the piston return spring to permit ready access to the snap ring. 
     In operation, the assembly-disassembly tool of this invention is affixed to the clutch, with actuation of the displacement means, via a wrench, compressing the return spring by axially inwardly displacing the snap ring cup so as to thereby relieve the end thrust of the cup against the snap ring and permit the ready manual insertion or removal of the snap ring. The same basic operation sequence is used whether it is desired to assemble or disassemble the clutch. 
    
    
     Other features and advantages of the invention will become more readily understood by persons skilled in the art when following the detailed description in conjunction with the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of an in-line three speed powershift transmission that has a plurality of fluid-actuated type of clutches with which the assembly-disassembly tool of this invention finds utility. 
     FIG. 2 is a perspective view of the component parts of the hydraulic clutch assembly-disassembly tool. 
     FIG. 3 is a longitudinal view, partly in section, of the clutch assembly-disassembly tool secured to the drum of a fluid-actuated type clutch after the removal of the clutch from the transmission shown in FIG. 1, with the clutch assembly-disassembly tool being shown in the inoperative or at-rest position. 
     FIG. 4 is a view similar to that of FIG. 3 with the clutch assembly-disassembly tool being shown in its operative or applied position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, the reference numeral 10 generally denotes a transmission of the constant-mesh-gear powershift type, having a housing 12 in which an input shaft 14, output shaft 16 as well as shafts 18, 20 and 22 are journalled for rotation. 
     While transmission 10 is substantially similar to transmission 130 (FIG. 7) shown and described in prior U.S. Pat. No. 3,893,345 (also assigned to the assignee of this invention), for ease of understanding, the description of this stucture and function will be substantially repeated herein. 
     Input shaft 14 is driven by means of a hydrodynamic torque converter (not shown) of known construction to which shaft 14 is connected, with the torque converter being in turn connected to any suitable source of power, such as an internal combustion engine (not shown). In addition, the torque converter impeller drives one or more pumps (not shown), of well known construction, to provide pressurized fluid to operate the various fluid actuated clutches, as well as lubricate the gears and bearings associated with transmission 10. 
     Connected to input shaft 14 is a gear 24 which is drivingly connected by means of an idler gear (not shown) with a gear 26, with gear 26 being journalled for rotation on shaft or countershaft 18. Shaft 22, is axially aligned with input shaft 14, can be connected thereto, for conjoint rotation therewith, by means of a clutch 28. Clutch 28, which is a multiple plate, fluid-actuated-type clutch of well known construction, includes a hub 30 connected to gear 24 by any suitable means, such as welding; a drum 32 which has a web 34 integral therewith, with web 34 being fixed to shaft 22 by any suitable means such as welding; and a plurality of interleaved friction plates 36 splined alternately to hub 30 and drum 32. 
     Friction plates 36 are confined between an annular end plate 40, located via a retainer ring 42 in retainer ring groove 44 of drum 32, and an annular piston 46, with the latter being provided with outer and inner seal rings 48 and 49 respectively. 
     Piston 46 is normally biased against web 34 by means of a piston return spring 50 confined between piston 46 and a spring retaining cup 52 that is secured against axial movement by a snap ring 54 located in snap ring groove 56 of shaft 22. Clutch 28 is engaged by supplying pressurized fluid behind piston 46 which serves to press plates 36 together so that hub 30 is frictionally connected to drum 32 through plates 36 in a manner well known in the art. 
     Gear 26 can be connected to countershaft 18 for conjoint rotation therewith by means of a clutch 60, with shaft or countershaft 20, which is axially aligned with countershaft 18, being connectable to countershaft 18 for conjoint rotation therewith by engagement of a clutch 62. Clutches 60 and 62 are the two halves of a double clutch and are joined by a common web 64 which is affixed to countershaft 18 by any suitable means, such as welding. Each one of clutches 60 and 62 is substantially similar to clutch 28 and will therefore not be described further. 
     At this time, it will be noted that a gear 66 is integral with drum 32 of clutch 28 and meshes with another gear 68 which is integral with the common drum of clutches 60 and 62. It should also be clear at this time that countershafts 18 and 20 are in the same vertical plane as input shaft 14 and shaft 22. Shaft 22 and countershaft 18 are interconnected by means of meshing gears 66 and 68 so that any given direction of rotation of one of these shafts, the other shaft will rotate in the opposite direction. In addition, since gear 24 is drivingly connected, via an idler gear, with gear 26, they, therefore, rotate in the same direction . Thus, engagement of clutch 28 conditions transmission 10 for what may be arbitrarily designated &#34;forward drive&#34;, and engagement of clutch 60 conditions the transmission for what may again be arbitrarily be termed &#34;reverse drive&#34; depending, of course, on the direction of rotation of input shaft 14. A gear 72 is fixed to shaft 22 and can be connected to output shaft 16, which is axially aligned with shaft 22, by means of a clutch 74 which is also substantially similar to previously described clutch 28. 
     A gear 76, which is in constant mesh with gear 72 is journalled for rotation on countershaft 20 and can be connected thereto for conjoint rotation therewith by means of a clutch 78, with clutch 78 again being substantially similar to previously described clutch 28. In addition, a gear 80 is fixed to countershaft 20 for conjoint rotation therewith, with gear 80 being in constant mesh with a gear 82 affixed to output shaft 16. 
     In view of the foregoing description, it will be apparent that a first forward speed ratio is provided by the engagement of clutches 28 and 78, a second speed ratio is provided by the continued engagement of clutch 28 and the engagement of clutch 62 instead of clutch 78, and a third speed ratio is provided by the continued engagement of clutch 28 and the engagement of clutch 74 instead of clutch 62. By engaging clutches 60 and 78, a first reverse speed ratio is provided, and by releasing clutch 78 and engaging clutch 62, a second reverse speed ratio is provided. A third reverse speed ratio is provided by engaging clutches 60 and 74. 
     Interleaved friction plates 36 are subject to wear and must, therefore, be replaced occasionally. It is also good practice to similarly replace, at the same time, the piston outer and inner seal rings 48 and 49, respectively. In some instances, this friction plate and seal ring replacement can take place without removing the clutch from the transmission, but more commonly the clutches are removed from the transmission for servicing. For example, after removal of clutch 28 from the transmission, the further removal of retainer ring 42 from groove 44 permits the removal of annular end plate 40 and the subsequent removal of friction plates 36. The replacement of piston seal rings 48 and 49 requires the removal of piston 46 from clutch drum 32 which in turn necessitates the removal of snap ring 54 in groove 56 of shaft 22. The use of the clutch assembly-disassembly tool of this invention, which is generally denoted by reference numeral 86, greatly simplifies this procedure. 
     As best seen in FIG. 2, tool 86 includes an externally expanding split retainer ring 88 whose adjacent end portions are provided with a pair of parallel and axially extending grip portions 90 which preferably take the form of thumb screws that are fixedly attached to retainer ring 88. Tool 86 further includes an outer annular member 92 whose external splines 94 are adapted to intermesh with splines 38 of drum 32 so as to locate member 92 relative to drum 32 as well as to keep member 92 from rotating. A pair of parallel support members 96 project outwardly from annular member 92, with the outer extremities of support members 96 being rigidly joined by a first bridging member 98. It is the function of retainer ring 88 to retain outer annular member 92 against axial movement out of clutch drum 32. 
     A further component of tool 86 takes the form of an inner annular member 102 which may be provided with a flange portion 104 and fits within outer annular member 92. Projecting outwardly from inner annular member 102 is a pair of second support members 106 whose outer extremities are rigidly joined by a second bridging member 108 that is located axially inwardly of a first bridging member 98. 
     A threaded bolt 112 is operatively engaged with a threaded bore 114 through first bridging member 98, with the threaded or inner end 116 of bolt 112 being adapted to be received in a curved recess 118 on second bridging member 108. 
     Turning now to FIG. 3, it shows clutch 42 after its removal from transmission 10 and after the removal of friction plates 36. Tool 86 has been attached to clutch 28 by first placing inner annular member 102 on spring retainer cup 52, and thereafter placing outer annular member 92 into clutch drum 32 and securing it against outer axial movement therefrom via retainer ring 88. Retainer ring 88 is manually located via grip portions 90 until it is fully located in retainer groove 44. Thereafter, bolt 112 is threaded through first bridging member 98 until bolt end portion 116 is received in recess 118 of second bridging member 108 and outer annular member 92 is fully abutted against retainer ring 88. It should be understood that at this time tool 86 is in the inoperative or at rest position in FIG. 3. 
     Turning now to FIG. 4, it should be clear that further rotary movement of bolt 112, such as via a wrench, in an inwardly direction, will axially displace inner annular member 102 away from outer annular member 92 thereby compressing return spring 50 by axially inwardly displacing snap ring cup 52 and thereby relieve the end thrust of cup 52 against snap ring 54 in groove 56 of shaft 22 so as to permit the ready manual removal therefrom of snap ring 54. After the removal of ring 54, rotary movement of bolt 112 in an outwardly direction will relieve the pressure of spring 50 and permit the detachment of tool 86 from clutch 28. It should also be understood that the same basic operational sequence is used whether it is desired to remove snap ring 54 to permit the removal of spring retaining cup 52 or to add snap ring 54 so as to confine retaining cup 52 after the replacement of piston seal rings 48 and 49. 
     It is the function of bridging members 98 and 108, and their support members (96 and 106, respectively) together with bolt 112 to function as means for displacing inner annular member 102 axially inwardly (toward piston 46) within clutch drum 32 relative to outer annular member 92, thereby compressing and axially displacing piston return spring 50 so as to permit the ready removal or insertion of snap ring 54 relative to snap ring groove 56. 
     Tool 86 may, of course, be so constructed that it can be completely dismantled, i.e., that the support members can be removed from both the annular members and the bridging members, for ready portability for field use where arbor presses or the like are not readily available. It should also be understood that tool 86 can be used on differing clutch sizes by having varying sizes of inner and outer annular members as well as differing sizes of retainer rings 88. 
     It should be apparent that the clutch assembly-disassembly tool of this invention provides a very simple as well as portable tool that is easy to operate, inexpensive to manufacture and obviates the need for an arbor press when rebuilding clutches of the type previously described herein. 
     From the foregoing, it is believed that those familiar with the art will recognize and appreciate the novel concepts and features of the present invention. Obviously, while the invention has been described in relation to but a single embodiment, numerous variations, changes and substitutions of equivalents will present themselves to persons skilled in the art and may be made without necessarily departing from the scope and principles of this invention. As a result, the embodiment described herein is subject to various modifications, changes and the like, without departing from the scope and spirit of the invention, with the scope thereof being determined solely by reference to the claims appended hereto.