GB1570230A

GB1570230A - Device for attaching to an output shaft for preventing unwanted reverse rotation of the output shaft

Info

Publication number: GB1570230A
Application number: GB8759/77A
Authority: GB
Original assignee: RAVINGER A
Current assignee: RAVINGER A
Priority date: 1976-03-16
Filing date: 1977-03-02
Publication date: 1980-06-25
Also published as: CH580766A5; AT351942B; DE2709253A1; FR2361236A1; ATA174577A; SE7702767L

Description

(54) DEVICE FOR ATTACHING TO AN OUTPUT SHAFT FOR PREVENTING UNWANTED REVERSE ROTATION OF THE OUTPUT SHAFT (71) I, ARPAD RAVINGLR, a Czecho- slovak national, of Kirchbergstrasse 63, Burgdorf Cm3400, Switzerland, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a device for atteaching to an output shaft for preventing unwanted reverse rotation of the output shaft. This invention also relates to a gearing system including a device of the invention and to a motor vehicle including the gearing system.

Driven output shafts are often susceptible to unwanted reverse movement. Thus, for example, it is mentioned that if a motor vehicle is parked facing up an incline, it may run backwards unless the hand brake is applied or unless there is an external stopping member such as a kerb. Even when the vehicle is being driven up an incline and it has momentarily to stop, for example because of traffic conditions, the vehicle may run backwards unless the hand brake is applied or unless the clutch is partially engaged. Such unwanted backward movement of the vehicle would not occur if a drive shaft from its gear box, or its propeller shaft, were prevented from unwanted reverse rotation.

It is an aim of the present invention to provide a device for attaching to an output shaft for preventing unwanted rotation of the output shaft.

Accordingly, the present invention provides a device for attaching to an output shaft for preventing unwanted reverse rotation of the output shaft, which device com- prises a frame, a plurality of pivotally mounted detent members which can pivot with respect to the frame and which each have a detent-acting toothed portion and a detent-pivotting projecting portion which is in a different radial plane to the detent acting toothed portion and which cannot rotate with respect to the detent-acting toothed portion, a collar having teeth for engaging the detent-acting toothed portions, and a lifting ring having depressions for receiving the detent-pivoffing projecting portions, the device being such that when it is in use the collar and the lifting ring are coaxially mounted about the output shaft and when the detent-acting toothed portions are engaged with the collar teeth and the detent-pivotting projecting portions are located in the lifting ring depressions then the collar locks the output shaft to the frame and prevents the unwanted reverse rotation of the output shafit, and the device also being such that an angular movment of the lifting ring causes the detentpivotting projecting portions to slide out of the lifting ring depressions and pivot the detent members to cause the detent-acting toothed portions to move out of engagement with the collar teeth and thereby free the collar from the frame to permit wanted reverse rotation of the output shaft with the collar rotating with the output shaft.

It is envisaged that the device of the invention will be especially useful for fitting to motor vehicles such for example as motor cars and lorries. Examples of other types of motor vehicles that can be fitted with the device are military and invalid vehicles. By preventing the backward slipping of the vehicles, it is envisaged that it will be easier than hitherto to start the motor vehicles on inclines since it will no longer be necessary to apply the vehicle hand brake. Anv machinery having a gearing system with an outpuit/drive shaft can be fitted with the device of the invention and such machinery may be stationary and does not need to be provided with wheels.

The detent member can be made in one piece. Alternatively, the detent member can be made in several pieces with, for example, the detent-acting toothed portion formed on one detent member piece and the detentpivotting projection portion formed on another detent member piece. The detent member pieces can then be secured together, for example by welding or by screws.

Preferably, the detent members are spring biassed to the position in which the detentacting toothed portions are engaged with the collar teeth and the detent-pivotting projection portions are located in the lifting ring depressions. If desired, the detent members can be so formed and constructed that they are biassed substantially solely by their own weight to the position in which the detent-acting toothed portions are engaged with the collar teeth and the detent-pivotting projection portions are located in the lifting ring depressions.

Preferably, the collar is rotatably mounted on a roller bearing at a first point along the output shaft, and is rotatably mounted on a freewheel device having grip rollers at a second point along the output shaft, the freewheel device allowing rotation of the output shaft in one direction only. Usually, the roller bearing and the freewheel device will each have an inner profile which corresponds to the outer profile of the output shaft. The output shaft may thus be, for example, externally grooved. The roller bearing and the freewheel device may then have a serrated outer profile.

The lifting ring may be moved by a lever and the lever is preferably adjustable so that the time when the lever moves the lifting ring can be adjusted. The lever may be adjusted by means oF an adjusting nut and bolt arrangement. When the device of the invention is for adjusting to an output shaft of a gearing system of a motor vehicle, the lever is advantageously actuated by a gear lever of the motor vehicle gearing system. Generally, the lever can be moved manuallv or automatically and it can be electrically, hydraulically or pneumatically actuated.

Embodiments of the invention will now be described solely by way 9f example with reference to the accompanying drawings in which: Figure 1 is a front sectional view of a first device in accordance with the invention and taken along the line A-A shown in Figure 2; Figure 2 is a side sectional view taken along the line B-B shown in Figure 1; Figure 3 is a side sectional view of a second device in accordance with the invention, the side sectional view being similar to that shown in Figure 2 but with a different actuation arrangement; Figure 4 shows a detail of a freewheel device for connecting the toothed collar to the driven output shaft; and Figure 5 shows a detail of a roller bearing for connecting the toothed collar to the driven output shaft.

Referring to Figure 1, there is shown a device for attaching to the driven output sha'ft g-- of- à gear box (not shown) of - an engine of a motor vehicle such as a motor car. The device comprises a stationary frame 1 which may be made from a single piece of material and may be round, quadrangular or polygonal. The frame 1 is firmly connected to the rear side of the gear box. The gear box is made longer by one compartment to accommodate the device shown in Figure 1 and the frame 1 is so mounted at the end of a journal of the shaft 8 that both the frame 1 and the shaft 8 share the same bearing. The bearing (not shown) is housed in a bearing space la shown in Figure 2.

The frame 1 is provided with fixed pivots 3 on which are pivotally mounted detent members 2.

The pivotally mounted detent members 2 each comprise a detent-acting toothed portion and a detent-pivotting projecting portion 2a. The detent-acting toothed portion is the lower left hand cross hatched toothed part of each cross hatched detent member 2 shown in the upper part of Figure 1. As shown in Figures 1 and 2, the detent-pivotting projecting portion 2a is in a different radial plane to the detent-acting toothed portion of each detent member 2 and the detent-pivotting projecting portion 2a cannot rotate with respect to the detent-acting toothed portion. Where possible, the detent members 2 are so designed that they move to an arresting position to be described below by their own weight. However, preferably, compression springs 4 are provided to assist in moving the detent members 2 to their arresting position.

The detent-acting toothed portions operate with teeth 5a on a disc or collar 5. There are fewer detent members 2 than there are teeth 5a on the collar 5. The teeth 5a are preferably short and are shaped as shown with a sloping flank. The detent members 2 act to prevent the motor vehicle from unwantedly moving backwards on an inclined surface when the brakes are not applied, the precise action of the detent members 2 being more fully described immediately hereinbelow.

In Figure 1, the detent-acting toothed portions of the detent members 2 are shown engaged with the teeth 5a of the collar 5.

Also, the detent-pivotting projecting portions 2a of the detent members 2 are shown engaged with recesses 9a in a lifting ring 9, which lifting ring 9 is mounted in the device by means of a retaining ring 12a located in a recess 12. In this position, the vehicle can stand on an ~ inclined surface, without its brakes being applied and without rolling backwards.

The vehicle can be driven backwards in reverse gear by virtue of the fact that the lifting ring 6 is connected to a lever 14, the lever 14 being connected to the gear box reversing selector fork above a pivot shaft 15. The lever 14 is mounted on the pivot shaft 15 which is itself mounted in an aperture 17a in a projecting arm 17 forming part of the frame 1. The aperture 17a allows the lever 14 to move in a clockwise and an anti-clockwise direction on the pivot shaft 15.

The lever 14 passes through an opening 10 positioned on the left side of the lifting ring 9 as viewed in Figure 1. Connection of the lever 14 to the lifting ring 9 is made at this location and a slot 11 accommodates the movement of the lever 14. It will be seen from Figure 1 that similar openings to the openings 10 and 11 are provided on the right side of the lifting ring 9 as viewed in Figure 1. The lever 14 can thus alternatively be connected to this side of the lifting ring 9 if it is more convenient due to the structure of the vehicle.

The position of the lever 14 with respect to the lifting ring 9 can be adjusted by means of an adjusting nut 16 and an associated adjusting belt 16a. The bolt 16a is connected to the lever 14 by means of a connecting member 16b. When correctly adjusted and reverse gear is engaged, the selector fork moves which causes the lever 14 to move. This movement of the lever 14 in turn causes the lifting ring 9 to rotate slightly such that the detent-pivotting projecting portions 2a move out of engagement with the recesses 9a of the ring 9. The movement of the detent-pivotting projecting portions 2a causes the detent members 2 to pivot. This causes the detent-acting toothed portions of the detent members 2 to move out of their en(ragement with the teeth 5a of the collar 5. The collar 5 is thus freed from the fixed frame 1 to allow the shaft 8 to rotate in the reverse direction as desired.

During this reverse rotation, the collar 5 will rotate with the shaft 8.

On disengagement of the reverse gear, the lifting ring 9 is returned by the lever 14 to the position shown in Figure 1 and the device will be ready automatically to prevent the vehicle rolling backwards down an incline. If it is desired deliberately to push the vehicle backwards, then reverse gear can be engaged and the clutch pedal depressed.

The collar 5 is rotatably mounted at two points along the shaft 8. Firstly, the collar 5 is mounted by means of a free-wheel device 6 having grip rollers as illustrated most clearly in Figure 4, the device 6 allowing the shaft 8 to rotate only in its normal direc- tion. Secondly, the collar 5 is mounted by means of a conventional roller bearing 7 as illustrated most clearly in Figure 5, the bearing 7 being the main support member for the collar 5 and allowing the shaft 8 to rotate in both its normal and its reverse directions. The inner profile of both the device 6 and the bearing 7 are formed to mate with the shaft 8 and may thus be, for example, serrated or splined. The outer profile of the device 6 and the bearing 7 may be serrated so as to prevent turning and thus provide a safety factor. The device 6 and the bearing 7 are held in position by two retaining rings 13 as shown in Figure 2.

The device 6 serves as a freewheel device for the collar 5 and thus allows the above described normal rotation of the shaft 8 during forward movement of the vehicle.

During reversing, the device 6 carries the collar 5.

The inner profile of the collar 5 is shaped, for example serrated, in the same way as the outside of the bearing 7 and the outside of the device 6. The collar 5 is stationary during forward movement of the vehicle and rotates with the shaft 8 only during the reverse movement of the vehicle when the detent members 2 are lifted. This lifting of the detent members 2 preferably occurs when the reversing gear wheel of the gear box, actuated by the gear change fork, is brought to a distance of aproximately 4 to 6 millimetres from the other gear wheel.

Referring now to Figure 3, similar parts as in Figures 1 and 2 have been given the same reference numerals in order to avoid undue repetition of description. In Figure 3, the second device in accordance with the invention is shown having an enlarged arm 17 on the frame 1. The arm 17 supports a quadrangular member 18 which serves as a guide for the adjusting members 16 and 16a. The adjusting member 16a may be serrated and it is provided with an opening 16c which receives the upper part of the lever 14 as shown. The gear shifting gate of the vehicle gear box co-operates with the toothed member 16d to cause movement of the lever 14. The movement of the lever 14 is allowed by the slot 16e. If so required, the lever 14 may be so arranged that the lifting ring 9 can be turned in one direction only.

The device shown in Figure 3 may be actuated by a separate lever, either manually or automatically and either hydraulically, electrically or pneumatically. The device may be actuated by a lever which is not necessarily associated with the gear lever of the vehicle.

It is to be appreciated that the embodiments of the invention described above have been given by way of example only and that modifications may be effected. Thus, if a device as shown in the drawing is used for lorries and trailers, then the device may be situated outside of the gear box and appropriately supported on the vehicle chassis.

The corresponding portion of the driving shaft will then be formed to match the inside of the device 6 and the bearing 7. Also, a device as shown in the drawings could be fitted to the drive shaft of a motor of a stationary machine where it is desired to prevent uncontrolled reverse rotation of the shaft.

WHAT I CLAIM IS: 1. A device for attaching to an output shaft for preventing unwanted reverse rotation of the output shaft, which device comprises a frame, a plurality of pivotally mounted detent members which can pivot with respect to the frame and which each have a detent-acting toothed portion and a detent-pivotting projecting portion which is in a different radial plane to the detentacting toothed portion and which cannot rotate with respect to the detent-acting toothed portion, a collar having teeth for engaging the detent-acting toothed portions, and a lifting ring having depressions for receiving the detent-pivotting projecting portions, the device being such that when it is in use the collar and the lifting ring are coaxially mounted about the output shaft and when the detent-acting toothed portions are engaged with the collar teeth and the detent-pivotting projecting portions are located in the lifting ring depressions then the collar locks the output shaft to the frame and prevents the unwanted reverse rotation of the output shaft, and the device also being such that an angular movement of the lifting ring causes the detent-pivotting projecting portions to slide out of the lifting ring depressions and pivot the detent members to cause the detent-acting toothed portions to move out of engagement with the collar teeth and thereby free the collar from the frame to permit wanted reverse rotation of the output shaft with the collar rotating with the output shaft.

2. A device according to claim 1 in which the detent members are so constructed that they are able to move solely by gravity to the position in which the detent-acting toothed portions are engaged with the collar teeth and the detent-pivotting projecting portions are located in the lifting ring depressions.

3. A device according to claim 1 or claim 2 in which the detent members are each made in one piece.

4. A device according to any one of the preceding claims in which the detent members are spring biassed to the position in which the detent-acting toothed portions are engaged with the collar teeth and the detent pivotting projection portions are located in the lifting ring depressions.

5. A device according to any one of the preceding claims in which the collar is rotatably mounted on a roller bearing at a first point along the output shaft, and is rotatably mounted on a freewheel device having grip rollers at a second point along the output shaft, the freewheel device allowing rotation of the output shaft in one direction only.

6. A device according to claim 5 in which the roller bearing and the freewheel device each have an inner profile corresponding to the outer profile of the output shaft.

7. A device according to claim 6 in which the roller bearing and the freewheel device each have a serrated outer profile.

8. A device according to any one of the preceding claims in which the lifting ring is moved by a lever.

9. A device according to claim 8 in which the lever is adjustable so that the time when the lever moves the lifting ring can be adjusted.

10. A device according to claim 9 in which the lever is adjustable by means of an adjusting nut and bolt arrangement.

11. A device according to any one of claims 8-10 which is for attaching to an output shaft of a gearing system of a motor vehicle, and in which the lever is actuated by a gear lever of the motor vehicle gearing system.

12. A device acording to any one of claims 8 to 10 in which the lever is electrically, hydraulically or pneumatically actuated.

13. A device for attaching to an output shaft for preventing unwanted reverse rotation of the output shaft, substantially as herein described with reference to the accompanying drawings.

14. A gearing system whenever including a device as claimed in any one of claims 1 to 13.

15. A motor vehicle whenever including a gearing system as claimed in claim 14.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. stationary machine where it is desired to prevent uncontrolled reverse rotation of the shaft. WHAT I CLAIM IS:

1. A device for attaching to an output shaft for preventing unwanted reverse rotation of the output shaft, which device comprises a frame, a plurality of pivotally mounted detent members which can pivot with respect to the frame and which each have a detent-acting toothed portion and a detent-pivotting projecting portion which is in a different radial plane to the detentacting toothed portion and which cannot rotate with respect to the detent-acting toothed portion, a collar having teeth for engaging the detent-acting toothed portions, and a lifting ring having depressions for receiving the detent-pivotting projecting portions, the device being such that when it is in use the collar and the lifting ring are coaxially mounted about the output shaft and when the detent-acting toothed portions are engaged with the collar teeth and the detent-pivotting projecting portions are located in the lifting ring depressions then the collar locks the output shaft to the frame and prevents the unwanted reverse rotation of the output shaft, and the device also being such that an angular movement of the lifting ring causes the detent-pivotting projecting portions to slide out of the lifting ring depressions and pivot the detent members to cause the detent-acting toothed portions to move out of engagement with the collar teeth and thereby free the collar from the frame to permit wanted reverse rotation of the output shaft with the collar rotating with the output shaft.

15. A motor vehicle whenever including a gearing system as claimed in claim 14.