Retention device

A retention device 35 couples a load adjustment device to a throttle valve 2 which determines the output power of an internal combustion engine and is arranged fixed for rotation on a throttle-valve shaft 11. A clutch disk 8 of the clutch is connected fixed for rotation with the throttle-valve shaft 11 and also with the clutch 13, and is secured by means of a clamping device 35. The advantageous development of the clamping device 35 in combination with a coupling pin 10 makes it possible to mount and to lock the clutch anchor plate or clutch disk 8 against rotation without radial play, with the throttle valve shaft 11 entirely mounted. In addition, the clutch disk 8 can be axially secured in simple manner.

FIELD AND BACKGROUND OF THE INVENTION 
The present invention relates to a retention device for a coupling, 
particularly a coupling of an engine loadadjustment device (1), wherein 
the load-adjustment device has a throttle valve (2) which determines the 
power output of an internal combustion engine and is connected, fixed for 
rotation, with a throttle-valve shaft (11) mounted in a throttle valve 
housing, and wherein the shaft can be connected via a clutch (13) to a 
drive motor, the clutch having a first coupling part connected fixed for 
rotation with the throttle-valve shaft (11) via a clutch disk (8). 
It is already generally known to secure the clutch of a throttle-valve 
shaft of a load adjustment device on the throttle-valve shaft. For this 
purpose, a clamping wedge is provided between the hub and the 
throttle-valve shaft, the wedge being clamped by a clamping screw which 
passes through it in a position which connects the hub with the 
throttle-valve shaft. In this way, locking against rotation is obtained. 
SUMMARY OF THE INVENTION 
In contradistinction to this, it is an object of the invention to arrange 
the clutch without radial play, in as flat as possible a construction, in 
rotation-locked manner on a shaft. 
According to the invention, the clutch disk (8) can be fixed on the 
throttle-valve shaft (11) by a coupling pin (10) which can be secured by a 
clamping device. In this way, the clutch can be secured in radial 
direction on the shaft in simple manner, the locking forces being 
maintained small by the advantageous arrangement of the coupling pin. 
Furthermore, by the arrangement in accordance with the invention it is 
possible substantially to preassemble the setting member and only then 
fasten the clutch disk to the throttle-valve shaft. 
For this purpose, it is advantageous that the clamping device (35) have at 
least one clamping part (36) of spring elasticity which can be pressed 
against the surface of the coupling pin (10). 
It is another feature of the invention that the clamping device (35) 
consists of a spring plate (37) which is fastened on the clutch disk (8) 
and has at least two opposite spring-elastic clamping fingers (38) which 
are bent off in the direction towards the surface of the clutch disk (8) 
which clamping fingers are each provided on one side with an end edge (39) 
which can be brought to rest against the surface of the coupling pin (10). 
In this way, one obtains an easily handled connection between clutch disk 
and throttle-valve shaft without exposing the throttle-valve shaft or the 
other parts to particularly large surface pressure since this type of 
connection can be advantageously employed as bayonet closure. 
As a further development of the invention, it is advantageous that the 
clamping fingers (38) be arranged in pairs and lie diametrically opposite 
two other clamping fingers (38) which are arranged in a pair. It is 
furthermore advantageous that the clamping fingers (38) be at least 
partially punched out and are on the one end integral with the spring 
plate (37) and have end edges (39) at the other end. 
An additional possibility in accordance with a further development of the 
device of the invention is that the clutch disk (8) as well as the spring 
plate are axially as well as radially secured via the coupling pin (10). 
It is furthermore advantageous that the clutch disk (8) can be secured 
axially as well as radially on the throttlevalve shaft (11) via the 
coupling pin (10), the coupling pin (10) extending through a hole (22) 
provided in the throttlevalve shaft (11). 
In accordance with a special feature of the invention, it is provided that 
the opposite end edges (39) of the clamping fingers (38) form an angle 
which is open in the direction of the surface, the end edges (39) 
extending parallel to the longitudinal central axis of the coupling pin 
(10). In this way the coupling bolt is fastened in the desired position in 
simple manner. 
It is of special importance in the device of the invention that the 
clamping part (36) form at its center with the surface of the clutch disk 
(8) a space to receive the coupling pin (10). 
It is of particular importance for the present invention that a slot 
opening (33) corresponding to the inside width of the coupling pin (10) is 
provided in the clamping part (36) and that, upon the mounting, the clutch 
disk (8) can be pushed together with the clamping part (36) over the 
coupling pin (10) and then turned until the coupling pin (10) is locked 
between the two end edges (39) of the clamping fingers (38). With the 
throttle valve shaft premounted, the clutch disk can advantageously be 
secured for rotation within a very short time and be mounted and fastened 
on the throttle-valve shaft without radial play. 
By the favorable arrangement of the individual parts and of the locking 
elements a very flat construction of the entire device is obtained. 
In accordance with a further embodiment of the invention, at least one 
clamping finger (38) has a recess (40) which grips over the coupling pin 
(10). 
For this purpose it is advantageous that the clamping finger (38) be 
provided on its free end facing the place of connection with a guide 
surface (41) which is inclined with respect to the surface of the clutch 
disk (8).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The setting member shown in FIG. 1 is part of a load adjustment device 1, 
parts of the load adjustment device having been omitted for the sake of 
simplicity in order better to show the parts which are essential to the 
invention. The load adjustment device 1 comprises an electric motor, 
indicated diagrammatically in the drawing, which is connected for drive 
via a gearing 7, merely diagrammatically indicated, with a throttle-valve 
shaft 11. Via the gearing 7 the setting forces of the electric motor are 
transmitted to a throttle valve 2 and, in this way, displacement of the 
valve 2 into the desired position is brought about. 
As can be noted from FIG. 1, the load adjustment device 1 can be displaced 
via an accelerator pedal, indicated diagrammatically in the drawing, in 
which connection by actuation of the accelerator pedal a lever of the load 
adjustment device 1 is shifted between an idle stop and a full load stop 
and can be urged by a return spring in the idling direction. The 
accelerator pedal is connected by a gas cable to a driver and thus to the 
throttle-valve shaft 11 so that upon actuation of the accelerator pedal 
the driver is displaced in the direction towards the full load stop. 
Return springs are connected to the driver and urge it in the idling 
direction. 
The load adjustment device 1 has, in addition to the electric motor, a 
gearing 7 which can be connected for drive with the throttle valve shaft 
11 via a clutch 13. 
As can be noted from FIG. 1, the throttle-valve shaft 11 extends through a 
throttle-valve connection 14 which is part of a throttle-valve housing. 
The throttle-valve shaft 11 is mounted for rotation by means of two needle 
bearings 15 in the housing of the throttle valve shaft 11. 
The drive of the throttle-valve shaft 11 is effected via a drive gear 16 
which is connected for drive to the electric motor. The drive gear 16 is 
mounted for rotation on the throttle-valve shaft 11 and can be connected 
via a coupling rotor 17 and a spring plate 21 to a clutch disk or pole 
disk 8 fixed for rotation with the throttle valve shaft 11. 
The clutch disk 8 is shown in further detail in FIGS. 2, 3 and 4. The 
clutch disk 8, as shown in FIG. 1, is connected by numerous rivets 12 to 
the clutch rotor 17 in such a manner that, within a small region, the 
clutch rotor 17 can be axially displaced when a magnet coil 20, forming 
part of the clutch 13, is acted on by current. The coil then attracts the 
clutch disk 8 via the clutch rotor 17 so that the disk comes against the 
end surface of the clutch rotor 17. In this way, there is a 
friction-locked connection between the clutch disk 8, the clutch rotor 17 
and the electric motor (not shown in the drawing) for the displacement of 
the throttle valve shaft 11. 
As can be noted from FIGS. 2 and 3, the clutch disk 8 is connected, fixed 
for rotation, to the throttle valve shaft 11 by a coupling pin 10. The 
clutch disk 8 has an elongated opening 33 to receive the coupling pin 10 
and the throttlevalve shaft 11 has a hole 22 into which the coupling pin 
10 is introduced in order, in this way, to produce a drive connection 
between the clutch 13 and the throttle-valve shaft 11. By the use of a 
coupling pin 10, the connecting forces or pressing forces for the 
connection in rotation between clutch 13 and throttle-valve shaft 11 can 
be kept very small. Furthermore, premounting of the clutch 13 on the 
throttlevalve shaft 11 is possible. 
The coupling pin 10 can be secured in the hole 22 of the throttle-valve 
shaft 11 by a clamping device 35. The clamping device 35 is developed as a 
spring plate 37 in the embodiment shown. The clamping device 35 consists 
of the spring plate 37 fastened on the clutch disk 8 and connected by 
numerous rivets to the clutch disk 8. 
In the spring plate 37 there are clamping fingers 38 which are arranged in 
pairs. Diametrically opposite these clamping fingers 38 there are two 
further clamping fingers 38 arranged in pairs. The spring plate 37, 
together with the individual clamping fingers, forms a sort of bayonet 
lock for the holding fast of the coupling pin 10. 
The clamping fingers 38 are at least partially stamped out and integral at 
one end with the spring plate 37. On the other end, they have front edges 
39 which rest in the end position of the coupling pin 10 against the 
surface of the coupling pin 10 and thus secure the clutch disk 8 both 
axially and radially on the throttle valve shaft 11. 
The opposite end edges 39 of the clamping fingers 38 advantageously form an 
angle which is open in the direction of the surface. The end edges 39 
extend parallel to the longitudinal central axis of the coupling pin 10. 
In this way, after the mounting of the clutch disk 8, the latter is held 
fast in simple manner on the throttle-valve shaft 11. By means of the 
downwardly bent clamping fingers 38 and the obliquely extending front 
edges 39, the coupling pin 10 is pressed in installed condition in simple 
manner against the surface of the clutch disk 8. 
In the clutch disk 8 there is an elongated opening 33 which is somewhat 
larger than the coupling pin 10 and the outside diameter of the 
throttle-valve shaft 11. In this way, the clutch 13, which is at least 
partially preassembled, can be mounted on the throttle-valve shaft 11. The 
clutch disk 8 is then pushed onto the throttle-valve shaft 11 until the 
clamping part 36 receives the coupling pin 10 which is already mounted on 
the throttle-valve shaft 11. Upon the mounting of the clutch disk 8, the 
latter is first of all pushed by means of the opening 33 over the coupling 
pin 10 (see FIG. 3), whereupon the clutch disk 8 is turned to such an 
extent in accordance with arrow 43 that the coupling pin 10 engages 
between the opposite end edges 39. In this way the mounting of the clutch 
disk is completed. 
In accordance with another embodiment, the clamping fingers 38 or at least 
one clamping finger 38 can be provided with a recess 40 which engages over 
the coupling pin 10. The recess 40 the same function as the two opposite 
end edges 39 of the clamping fingers 38. In order to facilitate the 
introduction of the coupling bolt 10 into the recess 40, the clamping 
finger 38 is provided on its free end, opposite the place of connection, 
with a guide surface 41 which is inclined with respect to the surface of 
the clutch disk 8.