Spring means for a clutch

A self-centering anti-rattle spring for a clutch is disclosed. The resilient spring is positioned between the circumference of a pressure plate of the clutch and the circumference of a flywheel of the clutch. The resilient spring acts to arrest vibration and tumbling of the pressure plate to reduce wear and noise encountered during clutch operation. The resilient spring also functions to align a rotatable drive member connecting the plate to the flywheel.

BACKGROUND OF THE INVENTION 
Heavy duty clutches, generally, and specifically those of the two-plate 
configuration, are subject to tumbling and torsional activity of their 
parts at idle speed and torsional activity at higher speeds when the 
clutch is released. In such arrangements the intermediate plate of the 
two-plate clutch or the pressure plate of a single-plate clutch has a 
tendency to tumble at slow speed and a tendency to clatter or vibrate back 
and forth at high speed as the edges of its drive lugs abut against the 
opposite edges of the drive lug slots. The first of these motions 
(tumbling) is caused by gravity. In this movement the lug slots on the 
intermediate or pressure plate seek support from horizontally opposed 
pairs of driving lugs, which pair of lugs constantly change relative 
position during rotation of the cover, imparting a tumbling motion to the 
intermediate or pressure plate. The second of these motions is caused by a 
torque loading being imposed on the intermediate plate through a 
non-uniform rotation of the engine, flywheel, and cover. At the same time 
the intermediate or pressure plate is attempting, due to inertia, to 
rotate uniformly. The rotational differences between the intermediate 
plate and the fly wheel create a torque loading on the intermediate plate. 
The torque loading can produce a vibratory motion in the intermediate 
plate that can cause the clutch to clatter. 
The unwanted tumbling and vibratory motion cause a "clunking" type noise in 
the clutch and, additionally, subject the clutch parts to undue wear. 
Although wearing can be provided for fairly satisfactorily by use of 
strengthened structural members, recent developments in the engine field 
have increased the torsional vibration, causing increased wear on the 
driving slots. Reduction of the torsionally induced clatter reduces the 
wear on the driving lugs and slots. 
Although various arrangements for the suppression of tumbling vibrations 
and rattling of clutch plates and clutch assemblies have been developed 
and are known to exist in the prior art, none of the known arrangements 
provide an extremely simple assembly which requires the use of no special 
mounting means and, therefore, is capable of utilizing standard clutch 
parts. Accordingly, it would be desirable to provide a clutch useable with 
the new engines that has a simply mounted vibration suppression unit to 
reduce the noise generated by the operation of the clutch. 
In this type of heavy duty clutch the intermediate plate moves axially 
during the operation of the clutch, and the resulting wear. The 
intermediate plate is also drivingly connected to the flywheel by drive 
pins that engage slots in the intermediate plate. It is very important 
that the drive pins be properly aligned with the slots in the intermediate 
plate to prevent binding during the axial movement of the intermediate 
plate. If the drive pins and slots are not properly aligned, the 
intermediate plate can be restricted in axial movement. If the 
intermediate plate is not free to move axially, an incomplete release of 
the clutch and/or erratic engagement of the clutch can result. 
SUMMARY OF THE INVENTION 
The invention is directed to a spring means for a clutch device. The clutch 
has a rotatable drive member having a substantially planar face. A 
circular flange extends from the outer periphery of the face. A driven 
member is positioned adjacent the drive member. An engaging plate means is 
provided that is rotatable with and axially moveable relative to the drive 
member. The engaging plate means has a circular outer periphery containing 
at least one slot therein. At least one lug extends radially inwardly from 
the circular flange for driving engagement with the slot on the engaging 
plate means. A spring means, positioned adjacent the circular flange, 
engages the lug to maintain the lug in alignment with the slot in the 
engaging plate means. The spring means also engages the engaging plate 
means whereby the spring means reduces torsional and tumbling induced 
rattle in the clutch. 
The invention is also directed to a spring means for a clutch as described 
above in which the clutch has a plurality of lugs extending from the 
circular flange of a drive member. Each lug includes a shaft positioned in 
and extending from the circular flange. A drive block, pivotally 
positioned on the end of the shaft, is in alignment with and in engagement 
with the slot in the engaging plate means. The spring means includes an 
attachment member that is positioned between the drive block and the 
circular flange. Resilient spring members extend from opposed sides of the 
attachment member. The spring members engage the circular flange and the 
engaging plate means whereby the spring means reduces torsional and 
tumbling induced rattle in the clutch. 
The invention is further directed to a spring means for a clutch to align 
the pivotal drive blocks, as described above, with the slots in the 
engaging plate means. The spring means is in engagement with and extends 
from the drive block. A portion of the spring means extends from the drive 
block and engages the face of the drive member whereby the spring means 
aligns the drive block with respect to the slot in the engaging plate 
means.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings for a better understanding of the invention, 
there is shown a spring loaded two-plate clutch 10 drivingly connected for 
unitary rotation with a flywheel 12. The flywheel has a substantially 
planar friction face 16 and a circular flange 15 that extends from the 
outer periphery of the friction face. The flywheel 12 is rotatably 
supported on a driving shaft 13 that extends from an engine or prime mover 
(not shown). The flange 15 extends axially from the outer periphery of the 
flywheel 12 in a direction away from the driving shaft 13. A clutch cover 
14 is secured to the circular flange 15. 
An output shaft, shown fragmentarily at 30, adapted to be clutched into a 
driving relationship with the flywheel 12, is piloted at its forward end 
in the flywheel and extends axially rearwardly therefrom through the cover 
14. A pair of driven members 32 and 34 are splined for unitary rotation 
and relative axial movement on the forward end of shaft 30 and are adapted 
to be pressed into driving engagement with the flywheel 12 and a limited 
axially moveable intermediate plate 36 disposed there between. Movement of 
the driven members and the intermediate plate is controlled by an axially 
moveable pressure plate 38. Pressure plate 38 is drivingly connected to 
the cover 14 by means of a plurality of lugs 40 extending axially from the 
rear surface thereof into registering slots 42 formed in the cover 14. The 
circular flange 15 extends over and radially encompasses the driven 
members, the intermediate plate and the pressure plate. The intermediate 
plate 36 is drivingly connected to the flywheel by means of a plurality of 
drive pins 44 extending radially from the circular flange 15 of the 
flywheel 12. The drive pins 44 extend from the circular flange in a 
direction towards the intermediate plate and are disposed for registering 
in drive slots 46 formed on the outer periphery of the intermediate plate 
36. The drive slots 46 are positioned axially in the intermediate plate 
and the sidewalls 49 of the drive slots are substantially perpendicular to 
the friction face 16 of the flywheel 12. 
The intermediate plate 36 is drivingly coupled to the flywheel 12 by the 
drive pins 44 which engage the drive slots 46. The intermediate plate is 
drivingly coupled with the output shaft 30 when the driven members 32 and 
34 are moved into frictional engagement with the flywheel and the 
intermediate plate. During the clutching and declutching of the clutch 10, 
the intermediate plate 36 moves axially approximately thirty to forty 
thousandths of an inch. 
The drive pins 44 comprise a shank or pin 45 that is securely positioned in 
an aperture 17 in the circular flange 15 of the flywheel. One end of the 
shank extends from the circular flange in a direction towards the 
intermediate plate 36. A drive block 47 is pivotally positioned on the end 
of the shank that extends from the circular flange. The drive block 47 is 
preferably rectilinearly shaped to bear against the sidewalls 49 of the 
rectilinear slots 46. A friction material can be placed on or against the 
portion of the shank 45 where the drive block 47 is positioned to assist 
in maintaining the drive block in the proper position during assembly of 
the clutch 10. 
The mechanism for engaging and disengaging the clutch devices is 
substantially the same as that described in U.S. Pat. No. 3,424,288 
granted to William H. Sink on Jan. 28, 1969. As the mechanism for 
operating the clutch device is described in detail in this earlier patent, 
that description will not be repeated herein. However, the disclosure of 
the above patent is hereby incorporated by reference into the 
specification of the present patent application. 
Because of the torque loading imposed on the intermediate plate 36, a 
clutch constructed as herein described suffers from the before mentioned 
clattering noise and consequently results in an increase in wear on the 
moving parts. To prevent the above difficulties, a plurality of spring 
means 96 are positioned between the inner periphery 98 of the circular 
flange 15 of the flywheel and the outer periphery 97 of the intermediate 
plate 36. 
The spring means 96 includes a substantially flat attachment member 99 that 
is positioned between the drive pin 44 and the inner periphery 98 of the 
circular flange 15 of the flywheel. The attachment member contains an 
aperture 100 that is disposed for being positioned on the shank 45 that 
connects to the drive block 47 of the drive pin 44. The positioning of the 
shank 45 through the aperture 100 acts to secure the attachment member in 
position with respect to the drive block 47 and inner periphery 98 of the 
circular flange 15. The attachment member 99 is normally larger than the 
drive block and the attachment member thereby provides a wear surface 
between the drive block 47 and the circular flange 15. 
Extending from opposed sides of the attachment member 99 are substantially 
flat spring members 101. The spring members are formed of a spring steel 
and extend from the attachment member in a direction along the outer 
periphery of the intermediate plate 36. The spring members and attachment 
member are normally wider than the intermediate plate and extend from each 
side of said intermediate plate. The spring members have an arcuate shape 
with the portion of the spring members adjacent the attachment member 99 
being in contact with the inner periphery 98 of the circular flange 15. 
The ends of the spring members that are spaced apart from the attachment 
member 99 are also in contact with the inner periphery 98 of the circular 
flange. The spring members 101 are in contact with the outer periphery of 
the intermediate plate 36 at a point that is substantially mid way between 
the ends of the spring members. 
The spring members 101 resiliently engage the intermediate plate 36. 
Although any number of spring means 96 can be utilized in the present 
invention there is usually a spring means associated with each drive pin 
44. Normally, the drive pin 44 and drive slots 46 are uniformly spaced 
around the outer periphery of the intermediate plate 36. Thus, the spring 
members 101 of the spring means 96 act to resiliently center the 
intermediate plate 36 relative to the circular flange 15 of the flywheel. 
As the spring members 101 are wider than the intermediate plate 36, the 
spring members will remain in resilient engagement with the intermediate 
plate as the intermediate plate moves axially with respect to the shaft 
30. It should be noted, however, that the spring force of the spring 
members 101 against the intermediate plate 36 is insufficient to prevent 
disengagement of the clutch 10. 
Positioned on each of the spring members 101 is a resilient flange 103. The 
flanges extend from the side of the spring members that are spaced apart, 
and in a direction away from the face 16 of the flywheel 12. As the 
flanges extend away from the spring members 101 the flanges generally 
converge towards the circular flange 15 of the flywheel. The flanges 
assist in positioning the intermediate plate 36 in the clutch 10. During 
the assembly of the clutch the spring means 96 and drive pins 44 are 
positioned in the circular flange 15 of the flywheel 12 prior to 
positioning the intermediate plate in the clutch 10. As the intermediate 
plate 36 is moved axially into the proper position the outer periphery of 
the intermediate plate contacts the end of the flanges 103 that are spaced 
apart from the spring members 101. As the ends of the flanges converge 
towards the circular flange the outer periphery of the intermediate plate 
can be positioned against the ends of the flanges. As the intermediate 
plate is moved axially towards the flywheel, the intermediate plate bears 
against and displaces the resilient flanges toward the circular flange 15. 
Since the flanges 103 are connected to the spring member 101, the spring 
members will also be displaced towards the circular flange 15 by any 
radial movement of the intermediate plate. The flanges 103 are located 
substantially at the midpoint of the spring member which is also 
substantially the point at which the spring member engages the 
intermediate plate. In this manner, the flanges 103 provide a mechanism 
whereby the spring members can be radially displaced as the intermediate 
plate 36 is moved axially into the proper position in the clutch 10. When 
the intermediate plate is in the proper position the spring members 101 
will be in resilient contact with the intermediate plate. 
On one side of the attachment member 99 there is a base section 105 that 
extends from the attachment member in a direction substantially 
perpendicular to the attachment member. The base section extends from the 
attachment member in a direction towards the intermediate plate 36. The 
base section 105 is substantially the same width as the side of the drive 
block 47 and the base section is disposed for contact with one side of the 
drive block. Defining a portion of the base section 105 are leaf springs 
107. The leaf springs extend from the base section 105 in a direction 
toward the face 16 of the flywheel 12. The leaf springs 107 are disposed 
for engaging the face 16 of the flywheel and for resiliently biasing the 
base section 105 against the side of the drive block 47. The leaf springs 
107 are disposed to engage the face 16 in a manner to maintain the base 
section 105 substantially parallel to the face. The engagement of the base 
section with the drive block maintains the drive block in proper alignment 
with the slot 46 in the outer periphery of the intermediate plate 36. The 
drive block is in proper alignment when the sides of the drive block that 
are adjacent the sidewalls of the slots are in substantially parallel 
relationship with the sidewalls of the slot. This orientation of the drive 
block with respect to the slot reduces any binding that can occur between 
the drive block and slot as the intermediate plate moves in an axial 
direction during the operation of the clutch. The leaf springs 107 and 
base section 105 also provide enough force against the side of the drive 
block to urge or wedge the drive block 47 against the pin 45 upon which 
the drive block is pivotally mounted. The urging of the drive block 
against the pin acts to hold the drive block in position on the pin. 
The operation of the clutch 10, including the spring means 96 will now be 
explained in greater detail. When the engine is in an idle condition, 
tumbling of the intermediate plate 36 can occur. This tumbling is resisted 
by the spring members 101 that extend from the attachment member 99 of the 
spring means 96. The spring members 101 engage the inner periphery 98 of 
the circular flange 15 of the flywheel 12 and the outer periphery of the 
intermediate plate 36. The spring members 101 resiliently engage the 
intermediate plate 36 and act to center the intermediate plate with 
respect to the circular flange 15. As the intermediate plate 36 is 
centered with respect to the circular flange 15, the intermediate plate is 
much less susceptible to gravitational forces that result in tumbling. 
Accordingly, the spring means 96 effectively reduces or eliminates the 
objectionable tumbling of the intermediate plate when the engine is 
idling. At the same time, the spring members 101 resiliently bear against 
the intermediate plate 36 and the circular flange 15 of the flywheel 12 to 
reduce or eliminate torsional vibration or rattle between the drive pins 
44 and drive slots 46. When the engine speed is increased substantially 
above idle conditions (approximately to 1100 r.p.m) centrifugal force on 
the intermediate plate 36 tends to prevent tumbling. The spring members 
101 of the spring means 96 then function to provide resilient engagement 
between the circular flange 15 and intermediate plate 36 to prevent 
torsional caused vibration or clattering. 
During the operation of the clutch, the intermediate plate 36 moves axially 
with respect to the output shaft 30 as the clutch is engaged and 
disengaged. During the axial movement of the intermediate plate 36 the 
drive slots 46 move with respect to the drive blocks 47. It is desirable 
to maintain the drive blocks in alignment with the sidewalls of the drive 
slots to prevent binding between the drive blocks 47 and the drive slots 
46 during the axial movement of the intermediate plate 36. To prevent this 
binding, the base section 105 is positioned against one face of the drive 
block, and the leaf springs 107 extend from the base section to engage the 
face 16 of the flywheel 12. The leaf springs 107, by engaging the face of 
the flywheel, maintain the base section 105 in an orientation that is 
substantially parallel to the face of the flywheel. Since the base section 
105 is held in engagement against one face of the rectilinear drive block 
47, the face of the drive block will also be maintained in a substantially 
parallel relationship to the face 16 of the flywheel. With one face of the 
rectilinear drive block parallel to the face 16 of the flywheel, the sides 
of the drive block that are adjacent the sides 49 of the drive slots 46 
are maintained substantially parallel to the sides of the drive slots 46. 
Accordingly, the base section 105 and leaf springs 107 act to maintain the 
drive block in alignment with the drive slot and to reduce any binding 
that might occur between the drive block and the drive slots 46 during 
axial movement of the intermediate plate 36. 
During the operation of the clutch 10, the drive block 47 can sometimes 
come into contact with the circular flange 15 of the flywheel 12. The 
drive block is normally constructed of a very hard material such as steel 
to reduce wear between the drive block and the drive slots 46 in the 
intermediate plate. However, the circular flange 15 of the flywheel is 
normally constructed of a relatively soft material such as cast iron. 
Accordingly, contact between the drive blocks 47 and the circular flange 
15 can have a very damaging result on the circular flange. The attachment 
member 99 of the spring means 96 is positioned between the drive blocks 47 
and the circular flange 15. The attachment member, therefore, provides a 
wear surface that prevents engagement between the drive blocks and the 
circular flange. This wear surface prevents damage from resulting to the 
circular flange due to contact between the drive block and the circular 
flange. If, during the replacement of the clutch 10, there appears to be a 
sufficient degree of wearing on the attachment member 99 from contact with 
the drive blocks 47, the attachment members can be easily replaced during 
the replacement of the clutch. The attachment members 99 are also much 
easier and cheaper to replace than replacing a flywheel 12 having a 
damaged circular flange 15. In addition, it is possible to construct the 
attachment members 99 of a material that can more easily handle the wear 
induced by contact with the drive block than the soft cast iron of the 
circular flange 15 of the flywheel 12. 
Although the spring means 96 has been described in detail, it should be 
understood that it is not always necessary to use the entire spring means 
in all applications. As shown in FIG. 6, it is possible to use only the 
attachment member 99 and the spring members 101 in the clutch 10. In this 
embodiment the attachment member is secured in position by the pin 45 that 
extends through the aperture 100 in the attachment member 99. The spring 
members 101 extend from the attachment member as previously described and 
engage the outer periphery of the intermediate plate 36. The spring 
members 101 resiliently engage the intermediate plate 36 and center the 
intermediate plate relative to the circular flange 15 of the flywheel 12, 
to reduce or eliminate tumbling and torsional vibration of the 
intermediate plate. 
FIG. 5, shows another embodiment of the invention where the attachment 
member 99, base section 105 and leaf springs 107 are utilized as described 
above. However, in this embodiment the spring members 101 are not 
utilized. In this embodiment the attachment member 99 is again secured in 
position by the pin 45 which extends through the aperture 100 in the 
attachment member. The attachment member is positioned between the drive 
block 47 and the inner periphery 98 of the circular flange 15. In this 
embodiment the leaf springs 107 and base section 105 function to align the 
drive block 47 in the drive slot 46 as previously described. In addition, 
the attachment member 99 provides a wear surface between the drive block 
and the inner periphery 98 of the circular flange 15. 
FIG. 7 shows a further embodiment of the invention where only the base 
section 105 and leaf springs 107 of the spring means 96 are utilized in 
the clutch 10. In this embodiment the base section 105 is secured to one 
face of the drive block 47. The base section is normally connected to the 
face of the drive block by a rivet 109. However, it should be understood 
that other suitable attachment means can be utilized. In this embodiment 
the base section 105 and leaf springs 107 function as previously described 
to align the drive block. However, the component parts of the spring means 
96 have been reduced by eliminating the attachment member 99 and spring 
members 101 and attaching the base section 105 directly to a face of the 
drive block. 
FIG. 8 shows an additional embodiment where one side 111 of a drive block 
47 contains two apertures 113. Two resilient spring means 115 are 
positioned in and extend from the aperture in the side 111 of the drive 
block. The spring means extend from the side 111 in a direction that is 
substantially perpendicular to the side. The spring means are disposed to 
resiliently engage the face 16 of the flywheel 12 to maintain the side 111 
of the drive block in substantially parallel relationship with the face 16 
of the flywheel. In this position the drive block is in proper alignment 
with the slot 46 in the intermediate plate 36. Thus, the embodiment shown 
in FIG. 8 provides another means for aligning the drive block with respect 
to the drive slot to reduce any binding that might occur during the axial 
movement of the intermediate plate. 
Having described the invention in detail with reference to the drawings, it 
is understood that such specifications are given for the sake of 
explanation. Various modifications and substitutions, other than those 
cited, can be made without departing from the scope of the invention as 
defined in the following claims.