GB1566735A

GB1566735A - Guard device for rotry shaft

Info

Publication number: GB1566735A
Application number: GB4784976A
Authority: GB
Original assignee: GKN Walterscheid GmbH
Current assignee: Walterscheid GmbH
Priority date: 1975-12-09
Filing date: 1976-11-17
Publication date: 1980-05-08
Also published as: FR2334877B1; DE2555202B1; DE2555202C2; IT1069641B; FR2334877A1

Description

(54) GUARD DEVICE FOR ROTARY SHAFT (71) We, JEAN WALTERSCHEID G.m.b.H,.

a Company organised and existing under the laws of the Federal German Republic, of Hauptstrasse, 5204 Lohmar/Rhld. 1, Germany, do hereby declare the invention tor which we pray that a patent may be granted to us, 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 guard device for protecting a rotary transmission shaft, e.g a Cardan shaft, such device comprising a tubular guard member which is mounted relative to the shaft by a bearing member engaging in an annular groove formed in the shaft, or part of an associated universal joint, said bearing member being retained in a connector piece which serves as a connection between the tubular guard member and a protective boot which covers the universal joint. Such a guard device will hereafter be referred to as a guard device of the kind specified.

In one form of guard device of this kind which has been proposed hitherto, fixation of the bearing member relative to the connector piece is obtained by providing elastic lugs, or tongues, on the connector piece and corresponding recesses in the bearing member. In addition to this, separate provisions are required for the engagement and fixa tion of the boot relative to the connector piece.

It is an aim of this invention to provide an improved guard device of the kind specified.

According to the present invention, we provide a guard device of the kind specified wherein the bearing member is provided ex eternally with a plurality of circumferentially spaced lugs, and the connector piece is formed with openings in which said lugs are received, the connector piece being provided with a stop face for providing location of the bearing member in one axial direc tin, and a connecting portion of the boot engaging the lugs of the bearing member to provide location thereof in the opposite di Bon.

As compared with the previous guard device referred to above this arrangement has an advantage in that it can be manufactured at considerably less expense. A simple connection is created between the bearing member and the tubular guard member by providing the connector piece with a plurality of openings for receiving the lugs of the bearing member. Moreover, assembly of the device is considerably simplified, and no tools are needed for assembling the device.

On the other hand, it cannot be pulled off without the aid of tools in the construction described hereafter.

The connector piece may have an enlarged region upon which the connecting portion of the boot is fitted, the openings extending into such enlarged region so that the connector piece is freely slidable over the bearing member when the latter is in engagement with its associated annular groove.

The advantage of this arrangement resides in that the lugs, which project beyond the body of the bearing member, can engage the stop face of the connector piece, and thus the diameter of the connector piece can be greater than it would need to be if it were to provide an abutment or stop face for the bearing member itself. As a result of this, a shaft, which for example may have a lemonshaped profile in transverse cross-section, of larger diameter may be utilised. The connector piece with the tubular guard may still be easily pushed over a heavier profile shaft up to the lugs of the bearing member, when this is elastically engaged in the annular groove.

According to another feature of this invention the connector piece may afford a stop face for the connecting portion of the boot, which stop face is axially offset relative to the stop face for the bearing member.

The outer region of the bearing member, in the region of the lugs, may be provided with reinforcing rib formations.

According to yet another feature of this invention the connector piece may be a plastics injection moulding including a grease nipple integrally formed thereon and having a passage extending therefrom and leadinng into the region of bearing faces of the bearing member.

This is possible for the connector piece owing to its simple form, from the point of view of production techniques.

The lugs on the outer circumference of the bearing member, and the corresponding openings in the connector piece may be arranged with the same spacing, the bearing member being further equipped with grease passages the openings of each of which can align with the opening of the passage extending from the grease nipple.

The advantage of this arrangement resides in that it is no longer necessary to watch the position of the grease channel in the bearing member when the device is put together.

In another form of the guard device it is possible for the lugs on the bearing member to be spaced apart by unequal distances over the outer circumference thereof, and for the bearing member to have a spacial grease hole which corresponds with the passage opening of the grease nipple.

The invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a part-sectional elevation of a transmission shaft with a guard device embodying the invention, FIGURE 2 is an end elevation of part of the guard device of Figure 1, and sections on the lines A-B and C-D thereof, FIGURE 3 is an end elevation of a further part of the guard device, and sections on the lines A-B and C-D thereof.

Referring firstly to figure 1, a transmission shaft, e.g. a Cardan shaft, 18 is provided with a guard device having telescopically interfitting tubular guard members 10, 11.

The guard member 10 is supported on a connector piece 9, which receives a bearing member 19, the bearing member 19 being itself slidably supported in an annular groove 14 formed in the surface of a spigot 22 of a yoke 23 of a universal joint in which the shaft terminates. A sealing boot 1 covers the universal joint, and a tubular connecting portion 4 of the boot is received on the connector piece 9. The opposite end of the shaft is similarly arranged, the outer tubular guard member 11 being supported on a connector piece which also has associated therewith a bearing member and a boot.

The bearing member 19, shown in more detail in Figure 3, is a one piece plastics component split at one point by a radial cut 26 so that it is capable of expansion. The bearing member 19 is provided on its inner circumferential face with a plurality of sliding bearing segments 24 with bearing faces 12 which engage in the annular groove 14 ..for relative rotation so that the bearing member can remain stationary while the shaft rotates. A locking ring 20 is embraced by the inner circumference of the connector piece 9 to prevent the segments 24 from slipping out of the groove 14 in service.

The locking ring 20 is provided at three circumferentially equi-distantly spaced regions on its outer circumference with lugs 6 reinforced by ribs 5. Adjacent to each lug 6 there is provided a grease passage 25.

The lugs 6 are received in correspondingly shaped, circumferentially spaced openings 3 in the connector piece 9, which embraces the bearing member 19. At one end the connector piece has a frusto-conical enlarged portion facing yoke 23, this enlarged portion being provided with a stop face 2 with which the connecting portion 4 of the boot 1 engages. The opposite end of the connector piece 9 is formed with a stop face 7 for the bearing member and is then of generally tubular form with a suitably decreasing cross-section to support the inner or outer tubular guard member as the case may be, there being provided external or internal connector buttons 8 which engage in corresponding apertures in the appropriate guard member.

The connector piece 9 is a plastics injection moulding, and is formed with an integral grease nipple 12 having a grease passage 27 which opens, in the interior of the connector piece, in the region of the stop face 7. When the bearing member is fitted, the grease passage 27 opens in the region of the bearing faces 21 of the bearing member 19 such that it coincides with a grease port 25 in the bearing member 19. Opposite the grease nipple 12, the connector piece 9 is formed with a securing eye 15 having an aperture 16 for a securing chain 17.

In order to assemble the guard device, the bearing member 19 must be expanded so that its segments 24 can be moved over the spigot 22 to engage in the annular groove 14. The appropriate tubular guard member will then be pushed into or over the cylindrical part of the connector piece, until the buttons 8 engage in the apertures in the tubular guard member to secure these components together, whereupon the assembly of tubular guard member and connector piece 9 can be pushed- over the shaft 18 until the lugs 6 of the bearing member 19 enter the openings 3 in the connector piece. This movement is halted when the lugs 6 of the bearing member abut the stop face 7. During this movement the- smaller diameter end of the frusto-conical enlarged portion of the connector piece 9 becomes engaged over the locking ring 20 of the bearing memebr and prevents the latter from being radially expanded and forced out of- the annular groove 14. The boot 1 will then be pushedover the assembly, its connecting portion 4 passing over the outer circumference 13 of the connector piece 9 until it abuts against the stop face 2 on the latter.

During this fitting of the boot, the connecting portion 4 thereof will have slipped over the ends of the lugs 6, to be situated forwardly of these lugs. The lugs are then constrained between the stop face 7 and the end of the connecting portion 4 of the boot.

When this state has been reached, no axial movement is possible for the guard device as a whole. When the fastener chain 17 has been secured to the vehicle or machine attached thereto (it being appreciated that a guard device of the type described is commonly utilised for guarding a shaft which connects a power take-off of a tractor to an attached machine or implement), the guard device is prevented from rotating, thereby providing safety by prevention of exterior access to rotating parts.

If it is required to move the guard device, this can be done by reversing the above described sequence of operations. Screw drivers or like implements would be utilised for releasing the connecting end portion of the boot from the connecting piece.

In the described embodiment, three lugs 6 are provided on the bearing member. It will be appreciated, however, that if desired a different number of lugs may be provided, either equally or unequally circumferentially spaced about the bearing member. If they are unequally spaced, the openings in the connecting piece would have to be similarly spaced, but it would be necessary to provide only one grease passage in the bearing member since assembly of it and the connecting piece would not be possible in a relative angular disposition other than that in which the grease passages were in alignment with the outlet of the passage 27 extending from the grease nipple 12.

WHAT WE CLAIM IS:- 1. A guard device of the kind specified wherein the bearing member is provided externally with a plurality of circumferentially spaced lugs, and the connector piece is formed with openings in which said lugs are received, the connector piece being provided with a stop face for providing location of the bearing member in one axial direction, and a connecting portion of the boot engaging the lugs of the bearing member to provide location thereof in the opposite direction.

2. A guard device according to claim 1 wherein the connector piece has an enlarged region upon which the connecting portion of the boot is fitted, the openings extending into such enlarged regions so that the connector piece is freely slidable over the bearing member when the latter is in engagement with its associated annular groove.

3. A guard device according to claim 1 or claim 2 wherein the connector piece is provided with a stop face for the connecting portion of the boot, which stop face is axially offset relative to the stop face for the bearing member.

4. A guard device according to any one of the preceding claims wherein the bearing member is provided with reinforcing rib formations in the region of the lugs.

5. A guard device according to any one of the preceding claims wherein the connector piece is a plastics injection moulding including a grease nipple integrally formed thereon, and having a passage extending from the grease nipple and leading into the region of the bearing faces of the bearing member.

6. A guard device according to claim S wherein the lugs on the bearing member, and the corresponding openings in the connector piece, are circumferentially equally spaced apart, the bearing member being provided with grease passages the openings of each of which can align with the opening of the passage extending from the grease nipple.

7. A guard device according to claim 5 wherein the lugs on the bearing member are spaced apart by unequal distances thereover, the bearing member having a grease hole corresponding in position to the passage opening of the grease nipple.

8. A guard device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the connector piece 9 until it abuts against the stop face 2 on the latter. During this fitting of the boot, the connecting portion 4 thereof will have slipped over the ends of the lugs 6, to be situated forwardly of these lugs. The lugs are then constrained between the stop face 7 and the end of the connecting portion 4 of the boot. When this state has been reached, no axial movement is possible for the guard device as a whole. When the fastener chain 17 has been secured to the vehicle or machine attached thereto (it being appreciated that a guard device of the type described is commonly utilised for guarding a shaft which connects a power take-off of a tractor to an attached machine or implement), the guard device is prevented from rotating, thereby providing safety by prevention of exterior access to rotating parts. If it is required to move the guard device, this can be done by reversing the above described sequence of operations. Screw drivers or like implements would be utilised for releasing the connecting end portion of the boot from the connecting piece. In the described embodiment, three lugs 6 are provided on the bearing member. It will be appreciated, however, that if desired a different number of lugs may be provided, either equally or unequally circumferentially spaced about the bearing member. If they are unequally spaced, the openings in the connecting piece would have to be similarly spaced, but it would be necessary to provide only one grease passage in the bearing member since assembly of it and the connecting piece would not be possible in a relative angular disposition other than that in which the grease passages were in alignment with the outlet of the passage 27 extending from the grease nipple 12. WHAT WE CLAIM IS:-

1. A guard device of the kind specified wherein the bearing member is provided externally with a plurality of circumferentially spaced lugs, and the connector piece is formed with openings in which said lugs are received, the connector piece being provided with a stop face for providing location of the bearing member in one axial direction, and a connecting portion of the boot engaging the lugs of the bearing member to provide location thereof in the opposite direction.