GB2154289A

GB2154289A - A non-slip clutch

Info

Publication number: GB2154289A
Application number: GB08503414A
Authority: GB
Inventors: Andre Millot
Original assignee: CARROY GIRAUDON SA
Current assignee: CARROY GIRAUDON SA
Priority date: 1984-02-15
Filing date: 1985-02-11
Publication date: 1985-09-04
Also published as: ES540318A0; FR2559564B1; DE3505325A1; ES8607495A1; IT8519487A0; FR2559564A1; IT1183339B; GB8503414D0

Abstract

A non slip clutch for selectively uncoupling a driven shaft 4 from a driveing shaft 1 also causing braking of the uncoupled driven shaft, comprising: a grooved ring on the driving shaft 1 and a pawl 5 pivotally mounted on the driven shaft 4; a control sleeve 11 having a finger 12 for actuating the pawl 5; a spring 13 for resiliently coupling the sleeve 11 for rotation with the driven shaft 4; and a brake 16 for braking the sleeve 11. Acutation of control means 18 brakes sleeve 11 resulting, after a limited relative movement of the sleeve 11 and the driven member 4 allowed by springs 13, in finger 12 exerting a camming action on pawl 5 to disengage it from ring 2 to release the clutch. A drive axle could be equipped with two such clutches each independently actuable to facilitate steering of single axled motor vehicles such as lawnmowers or cultivators. <IMAGE>

Description

SPECIFICATION A non-slip rotation coupling device The present invention relates to improvements to non-slip coupling devices for coupling a driven member such as a driven shaft (4) and a drive shaft (1) coaxial with the preceding one and adapted so as to allow uncoupling of the driven shaft from the driving shaft at will while causing at least simultaneous braking of the uncoupled driven shaft. The invention also relates to the application of such a device to a driven shaft assembly equipped with two wheels, as well as to motor vehicles having a single axle such as power driven cultivators, motor mowers, etc.

Motor vehicles with a single axle may receive, so as to facilitate handling thereof, equipment for causing a change of direction of the moving vehicle without one of the wheels having to be in contact with the ground.

For this, it is known to use differential devices which, however, are costly and require the use of a locking system for ensuring the drive force if one of the wheels lacks adhesion.

It is also known to use so called "quarter of a revolution" hubs, adapted so that each wheel has a free rotation over about a quarter of a revolution before being locked to the hub. Although such an arrangement is relatively inexpensive, it should however be noted that the drive thus obtained is unstable and it is difficult to hold the vehicle in the correct travel path after a change of direction. Holding it in the desired direction requires a considerable physical effort on the part of the driver.

Devices are also known comprising mobile drive dogs interposed between the drive axle and the wheel hub: disengagement of the dogs of one of the wheels causes the vehicle to turn. However, such an arrangement remains costly and the physical effort required for actuating it is not inconsiderable, especially when the operation is effected during the transmission of a high drive force.

The devices at present used have then this common disadvantage that the change of direction of the vehicle requires a more or less appreciable physical effort on the part of the conductor.

The aim of the invention is essentially to overcome this disadvantage and to propose an improved coupling device which uses the drive force for causing release of the driven shaft and which therefore, in its application to motor vehicles with a single axle, makes it possible for the change of direction of the vehicle to be effected under the action of the drive motor.

To this end, the device of the invention is characterized in that it comprises: a) a notched wheel locked in rotation with the drive shaft and a mobile finger resiliently returned into a notch of the wheel and being pivotably supported by a hinge pivot integral with the driven shaft, b) a cam track provided on the mobile finger and an actuating cam in abutment against this cam track arranged so that movement of the cam over the track generates a rotation of the finger about its pivot against the return force exerted thereon by return means, c) a sleeve coaxial with the driven shaft and locked in rotation therewith through resilient coupling means allowing a limited relative angular movement, with resilient return, of the sleeve with respect to the driven shaft, said sleeve supporting said cam, d) and fixedly supported braking means adapted to be placed selectively in cooperation, under the action of control means, with said sleeve. With this arrangement, actuation of the control means causes the braking means to come into contact with the sleeve which is then braked, the presence of the resilient coupling means allowing a limited relative angular movement of the driven shaft (still driven by the drive shaft) with respect to the sleeve, which movement causes, on the one hand, sliding of the cam over the cam track, raising of the finger and so uncoupling of the driven shaft from the drive shaft and, on the other hand, at the end of the angular relative sliding of the driven shaft and of the sleeve, locking of the driven shaft and the sleeve together and so at least braking of the driven shaft-the drive shaft continuing to rotate freely-, further to which release of the control means causes uncoupling of the braking means from the sleeve, the relative angular sliding in the reverse direction of the sleeve with respect to the driven shaft under the return action of the resilient coupling means, sliding in the reverse direction of the cam over the cam track and rotation in the reverse direction of the finger under the return action of its return means causing its reengagement in one of the notches of the notched wheel and so recoupling of the driven shaft to the drive shaft.

In a particular embodiment, the finger is supported by an arm of a cranked lever supported by the pivot and whose other arm is provided with the camming ramp.

Advantageously, the braking means comprise a drum coaxial with the sleeve and deformable radially for cooperation therewith.

In this case, it is advantageous for the drum to surround the sleeve.

In a particularly simple embodiment, the means for controlling the braking means are manual remote control means, comprising an operation handle and a connecting cable coupled to the braking means.

Another aspect of the invention also relates to a drive axle assembly equipped with two wheels, driven by said axle, which is characterized in that between the drive axle and the hub of each wheel there is interposed a coupling device in accordance with the invention and in that two actuating means are also provided for selectively actuating respectively the two coupling devices associated respectively with the two wheels.

Yet another aspect of the invention relates to a motor vehicle having a single axle, such as a motor driven cultivator, motor mower, etc, which is characterized in that the drive axle is-adapted as described above. The vehicle is then driven solely by selectively actuating one or other of the two handles which are available for the user without him having to exert any physical effort whatsoever.

The invention will be better understood from reading the detailed description which follows of a preferred embodiment given solely by way of non limitative example. In this description, reference is made to the accompanying drawings in which: Figure 1 is a cross sectional view of a coupling device in accordance with the invention; Figure 2 is a section through line ll-ll of Fig. 1; and Figure 3 is a schematical view of a motor vehicle with a single axle equipped in accordance with the invention.

Referring first of all to Figs. 1 and 2 a motor drive shaft or drive shaft 1 supports a ring 2 which is interlocked therewith and which has notches 3 on its periphery.

A driven shaft 4, for example in the form of a wheel hub, is coaxial with the drive shaft 1 and supports offcenter a cranked lever 5 situated opposite ring 2. Lever 5 is mounted for pivoting on a pin 6 secured to hub 4 whereas one of its ends is in the form of a finger or dog 7 adapted for engagement in a notch 3 of ring 2. To this same end is fixed a return spring 8 whose other end is fixed at 8a to hub 4, this spring returning dog 7 into a notch 3. The other arm of the lever 5 has a ramp 9 ending for example in a housing 10.

A sleeve 11 is engaged for free rotation about an axial part of hub 4. Sleeve 11 has a radial projection 12 directed inwardly and engaged in the housing 10 in lever 5, at one end of ramp 9. Moreover, two springs 1 3 are interposed between two fastening points 14 on hub 4 and a fastening lug 1 5 on sleeve 11 situated between these two points, so as to provide a resilient rotational coupling of the sleeve and the hub.

Finally, about sleeve 11 is disposed a fixed jaw 1 6 (for example fixed to a frame by a lug 17), adapted to be actuated by a cable 18 for pressing on sleeve 11.

In the position shown in Figs. 1 and 2, dog 7 is held engaged in a notch 3 of the ring by the spring, which provides the rotational coupling of the driven shaft or hub 4 with the drive shaft 1, the sleeve 11 also being rotated by the driven shaft 4 through springs 13.

If now, a pull is exerted on cable 18, for example by means of a handle (not shown) situated at its other end, jaw 1 6 is tightened and locks sleeve 11. With hub 4 still driven by the drive shaft 1, the ramp 9 of lever 5 is caused to slide over the radial projection 1 2 of the sleeve, which causes the lever to pivot, a dog 7 to leave the notch 3 and so hub 4 to be uncoupled from the drive shaft 1.

Simultaneously, the lug 1 5 of the sleeve 11 moves in a recess 1 9 of hub 4 whose length is determined so that lug 1 5 comes into abutment against the bottom 20 of recess 1 9 when the lever has pivoted sufficiently for hub 4 to be released from the drive shaft 1. The result is that the released hub 4 is braked by the sleeve 11.

As soon as the pull exerted on cable 18 is released, sleeve 11 is freed and, under the action of the return spring 1 3, it resumes its balanced position; projection 1 2 comes back into the housing 10 in the lever and, under the action of the return spring 8, dog 7 is engaged in a notch 3 of ring 2. Hub 4 is again coupled to the drive shaft 1.

With this arrangement, an active part of a braking member is capable of effecting a small angle rotation before being locked to the driven shaft; this travel is used for controlling removal of the dog which uncouples the drive shaft from the hub at the same time as the braked hub is interlocked with a part secured against rotation. Thus the hub has been released then braked against rotation solely under the action of the force of the drive shaft.

Fig. 3 shows one application of the device of the invention to a motor mower 21, shown in phantom, equipped with a drive axle 22 having two wheels 23a (the right hand wheel in Fig. 3 has been ommitted for the sake of clarity). Between each wheel hub 4 and the drive axle 22 is interposed a coupling device 23 in accordance with the invention such as described above and shown in Figs. 1 and 2.

Furthermore, the use has available a right hand actuating control lever 24, connected to the coupling device 23 of the right hand wheel by cable 25 and a left hand actuating control lever 26 connected to the coupling device (not visible) of the left hand wheel by a cable 27.

So as to cause machine 21 to turn to the right, for example, the user squeezes the right hand lever 24 which causes the right hand wheel to be uncoupled and braked, whereas the left hand wheel continues to be driven.

Steering the machine 21 therefore requires no appreciable physical effort and it is easy to follow a given path, without any instability.

As is evident and as it follows moreover already from what has gone before, the invention is in no wise limited to those of its modes of application and embodiments which have been more especially considered; it embraces, on the contrary, all variants thereof; In particular, the braking member may be a brake having one or more disks. Actuating of the brake may be provided by other means than a cable (hand wheel, actuating cylinders, etc).

Claims

1. A non slip coupling device for coupling a driven member such as a driven shaft (4) and a drive shaft (1) coaxial with the preceding one and adapted so as to allow the driven shaft (4) to be uncoupled at will from the drive shaft (1) while causing at least simultaneous braking of said uncoupled driven shaft, characterized in that it comprises in combination:: a) a notched wheel (2) locked in rotation with the drive shaft (1) and a mobile finger (7) returned resiliently (at 8) into a notch of the wheel (2) and being pivotably supported by a pivot (6) fixed to the driven shaft (4), b) a cam track provided on the mobile finger (7) and an actuating cam (12) bearing on this cam track (9) adapted so that movement of the cam (12) over the track generates rotation of the finger (7) about its pivot (6) against the return force exerted thereon by return means (8), c) a sleeve (11) coaxial with the driven shaft (4) and locked in rotation therewith by resilient coupling means (13) allowing a limited relative angular movement, with resilient return, of the sleeve (11) with respect to the driven shaft (4), said sleeve (11) supporting said cam (12), d) and fixedly supported braking means (1 6) adapted to be placed selectively in cooperation, under the action of the control means (18), with said sleeve (11), whereby actuation of the control means (18) causes the braking means (16) to come into contact with the sleeve (11) which is then braked, the presence of the resilient coupling means (13) allowing a limited relative angular movement of the driven shaft (still driven by the drive shaft) with respect to the sleeve (11), which movement causes, on the one hand, sliding of the cam (12) over the cam track (9), raising of the finger (7) and so uncoupling of the driven shaft from the drive shaft and, on the other hand, at the end of the relative angular sliding of the driven shaft and of the sleeve (11), interlocking of the driven shaft and the sleeve and so at least braking of the driven shaft-the drive shaft continuing to rotate freely-, following which release of the control means (18) causes uncoupling of the braking means (16) from the sleeve (11), the relative angular sliding in the reverse direction of the sleeve (11) with respect to the driven shaft under the return action of the resilient coupling means (13), sliding in the reverse direction of the cam (12) over the cam track (9) and rotation in the reverse direction of the finger (7) under the return action of its return means (8) causing reengagement thereof in one of the notches of the notched wheel (2) and so recoupling of the driven shaft with the drive shaft.

2. Coupling device according to claim 1, characterized in that the finger (7) is carried by one arm of a cranked lever (5) supported by the pivot (6) and whose other arm is provided with the cam ramp (9).

3. Coupling device according to claim 1 or 2, characterized in that the braking means (16) comprise a drum (16) coaxial with the sleeve (11) and radially deformable for cooperation therewith.

4. Coupling device according to claim 3, characterized in that the drum (16) surrounds the sleeve (11).

5. Coupling device according to any one of claims 1 to 4, characterized in that the means (18) controlling the braking means (16) are manual remote control means, comprising an actuating control lever (24, 26) and a connecting cable (25, 27) coupled to the braking means (16).

6. A drive axle assembly equipped with two wheels driven by said axle, characterized in that between the axle and the hub of each wheel is interposed a coupling device according to any one of claims 1 to 5, characterized in that it is provided with two actuating means (24, 26) for selectively actuating respectively the two coupling devices associated respectively with two wheels.

7. Motor vehicle with a single axle, which is driven, such as a motor driven cultivator, motor mower, etc, characterized in that the drive axle is arranged in accordance with claim 6.

8. A coupling device according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

9. A drive axle assembly according to claim 6 and substantially as hereinbefore described with reference to the accompanying drawings.

1 0. A motor vehicle substantially as hereinbefore described with reference to the accompanying drawings and as shown in Fig. 3 of the accompanying drawings.

11. Any novel feature or combination of features described herein.