Clutch release bearing with bistable spring washer

A clutch release bearing comprises a maneuvering member operated on by a control member, usually a clutch release yoke. A drive member in direct or indirect axial bearing engagement with the maneuvering member, when operated on by the latter, operates on the clutch release device of a clutch. An axially acting spring washer of the Belleville spring type urges the drive member against the maneuvering member and retains the drive membering relative to the maneuvering member in the axial direction. This spring washer is able to turn inside out selectively so as to assume one or other of two separate stable configurations. One of these is a concave configuration and the other is a convex configuration. One configuration is an inoperative configuration and the other is an operative one. One peripheral edge of the spring washer bears axially on the drive member when it is in the operative configuration. On its other peripheral edge is a set of lugs through which it bears on the maneuvering member. The spring washer and these lugs form a dihedron. The maneuvering member includes a circumferential groove cooperating with the lugs. It has one flank serving as an abutment to the lugs in the inoperative configuration of the spring washer while its other flank supports the lugs in the operative configuration thereof. As a result, the dihedral angle between the lugs and the spring washer remains the same in both the operative and the inoperative configuration.

BACKGROUND OF THE INVENTION 
1. Field of the invention 
The present invention is generally concerned with clutch release bearings 
of the type fitted to automobile vehicles, for example. 
2. Description of the prior art 
Known clutch release bearings generally comprise a maneuvering member which 
is adapted to be operated on by a control member, in practise a clutch 
release yoke, and a drive member in direct or indirect axial bearing 
engagement with the maneuvering member and which is adapted, when operated 
on by the latter, to operate on the clutch release device of a clutch. 
The present invention is more particularly directed to the case where the 
drive member is urged axially against the maneuvering member by a bistable 
axially acting spring washer, in other words an axially acting spring 
washer adapted to turn inside out selectively so as to assume one or other 
of two separate stable configurations one of which is a concave 
configuration and the other of which is a convex configuration and one of 
which is an inoperative configuration and the other of which is an 
operative configuration, said concave and convex configurations being 
defined relative to the same axial observation direction. 
A clutch release bearing of this type is described, for example in U.S. 
Pat. No. 4,608,741. 
The spring washer used in it is adapted to have one of its peripheral edges 
bear axially on the drive member in the operative configuration and has on 
its other peripheral edge at least one lug through which it is adapted to 
bear against the maneuvering member. 
In some at least of the embodiments envisaged, this lug is in a dihedral 
relationship to the remainder of the spring washer of which it forms part. 
Being substantially rectilinear, for example, it is intended to be braced 
through the edge of one end against a shoulder on the maneuvering member 
with the concave side of the dihedron which it forms with the spring 
washer facing axially away from the side of the spring washer through 
which the latter bears axially on the drive member in the operative 
configuration. 
In an alternative arrangement it is provided at its end with a right-angle 
lip and is intended to be hooked over the maneuvering member with the 
concave side of the dihedron that it forms with the spring washer facing 
axially towards the side of the spring washer through which the latter 
bears axially on the drive member in the operative configuration. 
Such use of a bistable axially acting spring washer has the advantage of 
facilitating assembly: with the axially acting spring washer in the 
inoperative configuration within the drive member, of which it forms part 
from the outset of the assembly process, the drive member and the 
maneuvering member are engaged together axially and, on completion of such 
axial engagement, the spring washer goes of its own accord to the 
operative configuration with its lug or lugs braced against or hooked onto 
the maneuvering member. 
The corresponding arrangement had proven and may yet prove satisfactory. 
However, it has the disadvantage of leading to non-negligible mechanical 
stressing of the root area through which the lug or lugs on the Belleville 
spring washer merge with the remainder. 
During assembly, the dihedral angle between the lugs and the spring washer 
changes value several times. 
Taking the example of rectilinear lugs designed to be operative in braking, 
this angle is initially, in the inoperative configuration, considerably 
larger than 90.degree., being in practise near 180.degree.. It is first 
reduced to a value of less than 90.degree. during the first phase of 
relative engagement between the drive member and the maneuvering member. 
It then returns to a value greater than 90.degree. when, at the end of 
such engagement, the spring washer turns inside out to assume the 
operative configuration. 
The corresponding mechanical stresses may lead to fracture. 
A general object of the present invention is an arrangement which makes it 
possible to avoid this disadvantage while making it possible to retain the 
advantage of assembly by simple relative axial interengagement of the 
drive member and the maneuvering member. 
SUMMARY OF THE INVENTION 
The present invention consists in a clutch release bearing comprising a 
maneuvering member adapted to be operated on by a control member, a drive 
member in direct or indirect axial bearing engagement with said 
maneuvering member and having a portion cooperable, when operated on by 
said maneuvering member, with the clutch release device of a clutch, and 
an axially acting spring washer of the Belleville spring type adapted to 
urge said drive member against said maneuvering member and to retain said 
drive member relative to said maneuvering member in the axial direction, 
wherein said spring washer is adapted to turn inside out selectively so as 
to assume one or other of two separate stable configurations one of which 
is a concave configuration and the other of which is a convex 
configuration and one of which is an inoperative configuration and the 
other of which is an operative configuration and has one peripheral edge 
adapted to bear axially on said drive member when it is in said operative 
configuration and on its other peripheral edge at least one lug by means 
of which it is adapted to bear on said maneuvering member, said at least 
one lug and said spring washer being in a dihedral relationship to each 
other, and wherein said maneuvering member comprises a circumferential 
groove adapted to cooperate with said at least one lug and having one 
flank adapted to serve as an abutment to said at least one lug for said 
inoperative configuration of said spring washer and its other flank 
adapted to support said at least one lug for said operative configuration 
of said spring washer, whereby the dihedral angle between said at least 
one lug and said spring washer may advantageously remain substantially the 
same for both of said configurations. 
When the spring washer turns inside out from its inoperative configuration 
to its operative configuration there occurs a simple change in the 
orientation of the spring washer, from concave to convex or vice versa, 
but there is no significant change in the shape of the combination 
consisting of the spring washer and the lug or lugs with which it is 
provided. 
This has the advantage of protecting the root area of the lug or lugs, as 
they are no longer stressed. 
The characteristics and advantages of the invention will emerge from the 
following description given by way of example with reference to the 
appended schematic drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in these figures, a clutch release bearing in accordance with the 
invention comprises a maneuvering member 10 which is adapted to be acted 
on by a control member 9, for example a clutch release yoke, and which is 
only partially visible in the figures, and a drive member 11 which is in 
direct or indirect axial bearing engagement against the maneuvering member 
10 and which has a portion cooperable, when operated on by the latter, 
with the clutch release device 8 of a clutch, consisting of the ends of 
the fingers of a diaphragm spring, for example. 
In a way that is known in itself the maneuvering member 10 comprises an 
axial sleeve 12 for fitting it onto some form of support and guide member 
(not shown). It further comprises a transverse flange 13 for the drive 
member 11 to bear on in the axial direction, extending annularly around 
the sleeve 12 and projecting away from its outside surface. 
In the embodiment shown in FIGS. 1 through 4, and for reasons that will 
emerge hereinafter, the outside surface of the sleeve 12 is generally 
frustoconical over part at least of its length, diverging towards the 
flange 13 from the end opposite that flange. 
The maneuvering member 10 may advantageously be molded from a synthetic 
material. 
In a way that is also known in itself, the drive member 11 comprises a ball 
bearing one race of which is adapted to bear axially against the 
maneuvering member 10 while the other is the aforementioned portion 
cooperable with the clutch release device of the clutch to be controlled. 
In the embodiments shown in FIGS. 1 through 6 it is the outer race 14 of 
this ball bearing which is adapted to bear against the maneuvering member 
10, to be more precise against its flange 13, this outer race 14 itself 
comprising to this end an upstanding transverse edge 15 extending radially 
towards the axis of the assembly and through which it bears on the flange 
13. 
In these embodiments it is the inner race 16 of the ball bearing 
constituting the drive member 11 which is cooperable with the clutch 
release device of the clutch. 
To this end it comprises at its free end an upstanding transverse edge 19 
extending radially away from the axis of the assembly. 
Alternatively, this free end could equally well have a rounded profile 
and/or be directed radially towards the axis of the assembly. 
Axial bearing engagement between the drive member 11 and the maneuvering 
member 10 is obtained directly by direct contact between the upstanding 
edge 15 of the outer race 14 of the ball bearing constituting the drive 
member 11 and the transverse flange 13 of the maneuvering member 10. 
As this clutch release bearing is in practise of the self-centering type, 
annular clearance is provided between the edge surface of the upstanding 
edge 15 of the drive member 11 and a rib 17 projecting radially from the 
outside surface of the sleeve 12 at the inside periphery of the flange 13 
on the maneuvering member 10, where this flange 13 merges with the sleeve 
12. 
These arrangements are well known in themselves and as they do not of 
themselves relate to the object of the present invention they will not be 
described in more detail here. 
In the embodiment shown in FIGS. 1 through 4 and for reasons that will 
emerge hereinafter the edge of the inner race 16 of the ball bearing 
constituting the drive member 11 facing towards the upstanding edge 15 of 
the outer race 14 is at least partially bevelled by a chamfer 18 on the 
side towards the axis of the assembly. 
In a way that is also known per se an axially acting spring washer 20 of 
the Belleville spring type is used to urge the drive member 11 axially 
against the maneuvering member 10 and, as this is a clutch release bearing 
of the maintained self-centering type, to secure resilient control over 
such axial bearing engagement. 
By virtue of arrangements of a similar kind to those described in the 
aforementioned U.S. Pat. No. 4,608,741, the spring washer 20 is a bistable 
spring washer by which is meant a spring washer which is adapted, by 
turning inside out, to assume selectively one or other of two stable 
configurations one of which is concave and the other of which is convex, 
while one of them is an inoperative configuration and the other of them is 
an operative configuration. In the operative configuration one of its 
peripheral edges bears axially on the drive member 11 and it has in one 
piece with it along its other peripheral edge at least one lug 21 through 
which it bears against the maneuvering element 10. 
It is to be understood that the concave and convex configurations of the 
spring washer 20 are defined relative to the same axial observation 
direction. 
This axial observation direction being, for example, that running from the 
upstanding edge 15 of the drive member 11 to the flange 13 of the 
maneuvering member 10, the spring washer 20 is concave in its inoperative 
configuration (FIG. 3) and convex in its operative configuration (FIG. 2). 
The spring washer 20 being generally frustoconical, it is as if, on 
changing between its concave and convex stable configurations, on 
respective sides of a transverse plane passing through its inside edge, it 
turns inside out. 
In the embodiments specifically shown in FIGS. 1 through 4, the spring 
washer 20 is designed to bear through its outside peripheral edge, that is 
to say its larger diameter peripheral edge, on the upstanding edge 15 of 
the drive member 11 when it is in its operative configuration and it is 
thus along its inside peripheral edge, that is to say its smaller diameter 
peripheral edge, that it features one or more lugs 21 through which it 
bears on the maneuvering member 10. 
Four lugs 21 regularly distributed in the circumferential direction in 
pairs at 90.degree. to each other are provided along the inside peripheral 
edge of the spring washer 20. 
From their root area 30 to their ends 31 these lugs 21 are rectilinear. 
Each lug 21 is at the same dihedral angle V as all the others to the spring 
washer 20. 
In accordance with the invention, for the purpose of cooperation with the 
lugs 21 that the spring washer 20 thus features, the maneuvering member 10 
comprises a circumferential groove 23 one flank of which is adapted, as 
will be explained later, to form an abutment for the lugs 21 in the 
inoperative configuration of the spring washer 20 whereas the other flank 
is adapted to support the lugs 21 in the operative configuration of the 
spring washer 20. 
The flank of the groove 21 that is to form an abutment for the lugs 21 of 
the spring washer 20 in the inoperative configuration of the latter is the 
flank 24 facing axially towards the portion of the drive member 11 
cooperable with the associated clutch release device, while the flank to 
provide a support for the lugs 21 in the operative configuration of the 
spring washer 20 is the flank 25 facing in the opposite axial direction, 
and thus in the direction away from the portion of the drive member 11 
cooperable with the associated clutch release device. 
In the embodiments shown in FIGS. 1 through 7, the groove 23 in the 
maneuvering member 10 is near the flange 13. 
In the embodiment shown in FIGS. 1 through 4, the groove 23 is in the 
outside surface of the sleeve 12 of the operating member and extends 
annularly and continuously in the circumferential direction around the 
axis of the latter. 
In the radial direction the groove 23 is substantially aligned with the 
upstanding edge 15 of the drive member 11. 
Its flank 24, which is the one facing axially towards the portion of the 
drive member 11 cooperable with the associated clutch release device, is 
straight and it is axially offset towards the drive member 11 relative to 
the flange 13 of the maneuvering member 10. 
This flank 24 delimits the rib 17 which is present at the root of the 
flange 13. 
R1 denotes the radius of the circumference along which its outside edge 
runs. 
In this embodiment, the other flank 25 of the groove 23 in the maneuvering 
member 10 intended to support the lugs 21 of the spring washer 20 in the 
operative configuration of the latter is inclined relative to the axis of 
the assembly, this flank 25 diverging from the flange 13 of said 
maneuvering member 10 as it moves away from said axis. 
R2 denotes the radius of the circumference along which its outside edge 
runs. 
In this embodiment, the radius R2 is less than the radius R1 and, for the 
inoperative configuration of the spring washer 20 (FIG. 4A), the free or 
drive ends 31 of the lugs 21 lie on a circumference whose radius R3 lies 
between these radii R1 and R2. 
In other words, in this embodiment the flank 24 of the groove 23 in the 
maneuvering member 10 that faces axially towards the portion of the drive 
member 11 cooperable with the associated clutch release device extends 
radially beyond the ends 31 of the lugs 21 of the spring washer 20 when 
the latter is in the inoperative configuration whereas, in the radial 
direction, the other flank 25 terminates short of the ends 31 of the lugs 
21. 
The radius R3 of the circumference on which lie the free ends 31 of the 
lugs 21 of the spring washer may be substantially equal to the radius R2 
of the circumference around which runs the outside edge of the flank 25 of 
the groove 23 in the maneuvering member 10. 
In this embodiment the spring washer 20 is originally fitted to the drive 
member 11 (FIG. 4A), disposed axially between the upstanding edge 15 of 
the outer race 14 of the ball bearing constituting the drive member 11 and 
the corresponding edge of the inner race 16 of this ball bearing; it will 
therefore be readily understood that the chamfer 18 on this edge 
advantageously makes more room available at his location for the spring 
washer 20. 
At this time the spring washer 20 is in the concave inoperative 
configuration and, as shown, bears on the inner race 16 of the ball 
bearing constituting the drive member 11. 
In this inoperative configuration the lugs 21 on the spring washer 20 
extend towards the maneuvering member 10 and, depending on its dimensions, 
the spring washer 20 is then centered either by virtue of its lugs 21 
bearing on the upstanding edge 15 of the ball bearing constituting the 
drive member 11 or through contact of its outside peripheral edge with the 
deflector 15' usually fitted inside a ball bearing of this kind. 
On relative axial engagement of the drive member 11 and the maneuvering 
member 10, favored by the frustoconical shape of the outside surface of 
the sleeve 12 of the latter, for example (as schematically represented by 
the arrow Fl in FIG. 4A) on axial engagement of the drive member 11 onto 
the maneuvering member 10, it is through the free ends 31 of the lugs 21 
on the spring washer 20 that, by virtue of the geometrical arrangements 
already described, the drive member 11 comes axially into contact with the 
maneuvering member 10, the free ends 31 of the lugs 21 coming into 
abutting relationship with the flank 24 of the groove 23 in the 
maneuvering member 10 facing axially towards the drive member 11, before 
the upstanding edge 15 of the drive member 11 comes into contact with the 
flange 13 on the maneuvering member 10 (FIG. 4B). 
Thus as axial engagement of the drive member with the maneuvering member 10 
continues, the reaction force then exerted on the lugs 21 of the spring 
washer 20, as shown by the arrow F2 in FIG. 4B, the outside peripheral 
edge of the latter bearing against the edge of the inner race 16 of the 
drive member while its lugs are supported against the flank 24 of the 
groove 23 in the maneuvering member 10, is transmitted via the lugs 21 to 
the inside peripheral edge of the spring washer 20. Beyond a certain 
force, corresponding to a certain travel, the spring washer 20 suddenly 
turns inside out from its concave inoperative configuration to its convex 
operative configuration (FIG. 1). 
At the same time, and as shown by the arrow F3 in FIG. 4B, the lugs 21 of 
the spring washer 20 rotate towards the axis of the assembly so that the 
spring washer 20 bears through the lugs 21 against the flank 25 of the 
groove 23 in the maneuvering member 10 while its outside peripheral edge 
bears axially against the upstanding edge 15 of the drive member 11 and so 
urges the latter elastically against the flange 13 of the maneuvering 
member 10. 
On the change from the inoperative configuration of the spring washer 20 to 
its operative configuration, the combination that the spring washer 20 
forms with the lugs 21 retains substantially the same shape, due to the 
presence of the groove 23 on the maneuvering member 10 and to the specific 
configuration of this groove 23, and also by virtue of the fact that, the 
free ends 31 of the lugs 21 then lying between the flanks 24 and 25 of the 
groove 23 in the radial direction and short of the outside edge of the 
radially larger flank (24) in the radial direction, the lugs 21 are 
already as it were pre-engaged in the groove 23. 
Thus by virtue of the groove 23 in the maneuvering member 10 the dihedral 
angle V between the spring washer 20 and the lugs 21 thereof can 
advantageously remain substantially the same at all times and in 
particular may advantageously remain substantially the same in the 
inoperative and the operative configurations of the spring washer 20. 
In the embodiment shown in FIGS. 5 and 6, each of the lugs 21 on the spring 
washer 20 features at least one elbow bend 29 and, in the inoperative 
configuration of the spring washer 20, bears on a cylindrical bearing 
surface 28 on the drive member 11 through this elbow bend 29. 
This cylindrical bearing surface 28 is formed by the edge surface of the 
upstanding edge 15 of the drive member 11. 
Each of the lugs 21 is generally S-shaped having in succession, beginning 
at the spring washer 20, two elbow bends 27 and 29 with their concave 
sides facing in opposite directions and it is through the second elbow 
bend 29, that farthest away from the spring washer 20, that in the 
inoperative configuration the lug 21 bears against the cylindrical bearing 
surface 24 on the drive member 11. The flank 25 of the groove 23 in the 
maneuvering member 10 which supports the lugs 21 on the spring washer 20 
is straight and substantially perpendicular to the axis of the assembly. 
Thus in this embodiment both the flanks 24 and 25 of the groove 23 are 
straight. 
Taken overall, that is ignoring their elbow bends, the lugs 21 of the 
spring washer 20 are once again, as previously, at a dihedral angle V to 
the spring washer 20, this dihedral angle being measured, for example, 
relative to the line which joins their root area 30 to their free end 31. 
Also as previously, when the spring washer 20 is in the inoperative 
configuration (FIG. 6) the lugs 21 extend towards the maneuvering member 
10, each lug 21 then, taken as a whole, extending in a substantially axial 
direction. In this inoperative configuration the spring washer 20 is 
centered by the lugs 21, the elbow bends 29 of which bear against the 
cylindrical bearing surface 28 on the drive member 11 at this time, as 
already explained. 
The drive member 11 is assembled with the maneuvering member 10 as 
previously and on completion of such assembly, after the spring washer 20 
has turned inside out, the lugs 21 on the latter bear on the flank 25 of 
the groove 23 in the maneuvering member 10 without there being any 
significant change in the value of the dihedral angle V that they form 
with the spring washer 20. 
In the embodiment shown in FIG. 7 it is through its outer race 14 that the 
ball bearing constituting the drive member 11 is cooperable with the 
clutch release device of a clutch and it is therefore its inner race 16 
which has an upstanding edge 15 extending axially away from the axis of 
the assembly and through which it bears on the flange 13 of the 
maneuvering member 10. 
The groove 23 which the maneuvering member 10 features to support the lugs 
21 of the spring washer 20 is then on the inside surface of a ring 35 
projecting axially from the outside edge of the flange 13 of the 
maneuvering member 10, parallel to and in the same direction as the sleeve 
12 of the maneuvering member 10. 
It is through its inside peripheral edge that the spring washer 20 is 
adapted to bear on the drive member 11, to be more precise on the 
upstanding edge 15 thereof, and it is therefore its outside peripheral 
edge that has at least one lug 21, in practise at least two lugs 21 
appropriately distributed in the circumferential direction. 
Thus four lugs 21 are provided at the outside peripheral edge of the spring 
washer 20, for example, as previously. 
For the inoperative configuration of the spring washer 20 (not shown) the 
flank 24 of the groove 23 in the maneuvering member 20 which faces axially 
towards the portion of the drive member 11 cooperable with the associated 
clutch release device ends radially short of the free ends 31 of the lugs 
21 of the spring washer 20 whereas the other flank 25 extends radially 
beyond said free ends 31. 
In other respects the arrangements are of the same type as previously 
described. 
In particular, the dihedral angle V that the lugs 21 form with the spring 
washer 20 advantageously remains substantially the same in both 
configurations of the spring washer 20, as previously. 
In the embodiment shown in FIGS. 8 and 9, the groove 23 in the maneuvering 
member 10 is once again in the outside surface of the sleeve 12 thereof 
but, instead of being near the flange 13, it is near the free end of the 
sleeve opposite the flange, on the side towards the portion of the drive 
member 11 cooperable with the clutch control device and the spring washer 
20 bears on the side of the drive member 11 facing away from the flange 
13. 
The inner race 16 of the ball bearing constituting the drive member 11 
bears on the flange 13 of the maneuvering member 10 and it is therefore 
through the outer race 14 of this ball bearing, appropriately extended 
and/or shaped to this end, that the drive member 11 is cooperable with the 
clutch release device of a clutch. 
It goes without saying, however, that the converse arrangement can be 
adopted, as previously. 
The flank 24 of the groove 23 which is axially nearer the flange 13 and is 
adapted to serve as an abutment for the lugs 21 on the spring washer 20 in 
the inoperative configuration of the latter faces axially towards the 
portion of the drive member 11 cooperable with the associated clutch 
release device, as previously. 
Also as previously, this flank is straight. 
The flank 25 of the groove 23, that axially farthest away from the flange 
13 and adapted to support the lugs 21 of the spring washer 20 in the 
operative configuration of the latter, faces in the opposite axial 
direction and thus, as previously, in the direction away from the portion 
of the drive member 11 cooperable with the associated clutch release 
device. 
This flank is inclined to the axis of the assembly, the lugs 21 of the 
spring washer 20 being rectilinear in this embodiment, as in those 
described with reference to FIGS. 1 through 4 and 7, forming a dihedron 
with the spring washer 20. 
The inner race 16 of the ball bearing constituting the drive member 11 is 
generally cylindrical and the spring washer 20 bears on its edge facing 
away from the flange 13 of the maneuvering member 10. 
The outer race 14 of this ball bearing is also generally cylindrical. 
It will therefore be noted that this embodiment has the advantage of being 
very simple to manufacture. 
To assemble it, as shown in FIG. 9, the maneuvering member 10 may be 
disposed vertically and there are then fitted axially onto the maneuvering 
member 10 first the drive member 11, until it butts up against the flange 
13, and then the spring washer 20, at this stage independent of the ball 
bearing constituting the drive member 11, until the lugs 21 thereof butt 
up against the straight flank 24 of the groove 23 in the sleeve 12. 
It is then sufficient, using a cylindrical tool 35 as schematically 
represented in chain-dotted outline in FIG. 9, to cause the spring washer 
20 suddenly to turn inside out. 
Once this has been done, the spring washer 20 is applied against the edge 
of the inner race 16 of the ball bearing constituting the drive member 11 
while, as previously, its lugs 21 bear on the inclined flank 25 of the 
groove 23 in the maneuvering member 10. 
In the embodiment shown in FIG. 10 the outer race 14 of the ball bearing 
constituting the drive member 11 is shaped at the end through which it is 
cooperable with the clutch release device of a clutch. 
The resulting curved part 36 of the outer race 14 may then serve to secure 
the sudden turning inside out of the spring washer 20 during assembly. 
In this case the spring washer 20 is fitted in advance to the corresponding 
ball bearing, as in the embodiments of FIGS. 1 through 7. 
It will be noted that in all the embodiments described and shown the 
concave side of the dihedron formed by the spring washer 20 and its lugs 
21 faces towards the side of the spring washer 20 through which, in the 
operative configuration, the latter bears axially on the drive member 11. 
In all cases the lugs 21 of the spring washer advantageously bear through 
one of their surfaces, and not through their end, against the maneuvering 
member 10. 
It is to be understood that the present invention is not limited to the 
embodiments described and shown but encompasses any variant execution 
and/or combination of their various component parts. 
In particular, the groove in the maneuvering member need not necessarily be 
circumferentially continuous. 
To the contrary, it may be circumferentially discontinuous in which case 
indexing means are provided between the maneuvering member and the spring 
washer so that the lugs on the latter are correctly lined up with the 
corresponding sections of a groove of this kind. 
Also, the peripheral edge of the spring washer opposite that carrying the 
lugs may be crenelated to a greater or lesser degree and may even feature 
circumferentially distributed lugs. 
Finally, in the embodiments shown in FIGS. 1 through 7 the spring washer is 
not necessarily fitted in advance to the drive member especially when, 
there being sufficient annular space between the sleeve of the maneuvering 
member and the inner race of the ball bearing constituting the drive 
member, it is possible to use a tool to push the spring washer axially 
when, already fitted to said maneuvering member, said drive member is 
already butted up against the flange of the latter.