GB2207217A

GB2207217A - Shaft coupling

Info

Publication number: GB2207217A
Application number: GB08816690A
Authority: GB
Inventors: Hubert Grosse Entrup; Clemens Nienhaus
Original assignee: GKN Walterscheid GmbH
Current assignee: Walterscheid GmbH
Priority date: 1987-07-18
Filing date: 1988-07-13
Publication date: 1989-01-25
Also published as: DE3723910C1; IT8805190A0; JPS6430926A; FR2618194A1; GB8816690D0; IT1225135B

Description

1 BT/87004GB1 SHAFT COUPLING This invention relates to a shaft coupling

comprising a male shaft member having a plurality of radially outwardly projecting axially extending splines and a female shaft member releasably engaged about said male member and having cooperating radially inwardly projecting axially extending splines.

Shaft couplings of the type described above are known, for example in agricultural implement drives between the power take off shaft of a tractor and 6 drive shaft of an agricultural implement. A particular shaft coupling of this type is described and illustrated in GB-A-2149883 wherein means are provided for preventing rotational play between the male and female shaft members in the direction of torque transmission. Such means comprises a separate radially movable spline piece projecting through a radially extending bore in the female member into contact with a spline flank of the male member, the spline piece being wedgingly engaged with a male member spline by means of a screw carried by an external sleeve surrounding the female member and engaging with a head of the spline piece. In this construction the splihe piece comprises a partial spline of the female member which, when wedged into engagement with a male member spline by the screw as described above, results in a slight relative rotational movement between the male member and female member against the direction of rotation in which torque transmission occurs so that, in the direction of torque transmission, all of the spline flanks of the male and female members are in torque transmitting engagement. A disadvantage of this 2 construction is that, if the direction of torque transmission is reversed, torque would then be transmitted through the partial spline piece which is undesirable.

It is an object of the present invention to provide an improved shaft coupling having a locking spline piece which will enable full torque transmission between engaging spline flanks of the male and female members in either direction of rotation.

In accordance with the invention there is provided a shaft coupling comprising a male shaft member having a plurality of radially outwardly projecting axially extending splines; a female shaft member releasably engaged about said male member and having cooperating radially inwardly projecting axially extending splines; a separate locking spline piece located within a radially extending bore in said female member and comprising an axially extending locking spline engageable between two adjacent splines of the male member, said locking spline having a flank selectively cooperable with a corresponding one of the flanks of said two adjacent' splines of the male member; pressure means for urging said spline piece radially inwardly of said bore; a central longitudinally extending axis of said locking spline being offset laterally of the longitudinal axis of said bore whereby said flank of the locking spline is wedgingly engageable under the action of said pressure means with a said corresponding spline flank of the male member restraining said male and female members against rotation relative to one another, The bore in the female member is conveniently of circular cross sectional form and the locking spline 3 piece conveniently comprises a body portion of complimentary circular cross sectional form to that of said bore, the locking spline being provided at the radially inward end of said body portion, whereby, upon release of said pressure means, the locking spline piece may be withdrawn radially outwardly of said bore and rotated therein for selective cooperation of said locking spline flank with a said corresponding spline flank of the male member.

The construction described in the preceding two paragraphs thus provides a separate locking spline piece which is readily withdrawable and reinsertable in the coupling according to the desired direction of torque transmission between the male and female members of the coupling.

The shaft coupling conveniently further includes a locking sleeve carrying said pressure means thereon and surrounding said female shaft member and being movable axially thereof, spring means being provided to bias said sleeve from an inoperative position to an operative position wherein said pressure means is engageable with said locking spline piece. Coveniently the locking spline piece includes a head portion at the radially outward end of the body portion for engagement-by said pressure means.

Conveniently a plurality of blocking members are carried within radially extending bores in the female member of the coupling for engagement within a circumferential recess of the male member, the blocking members being engageable by said sleeve in its said operative position for restraining said male and female members against axial separation.

4 The pressure means conveniently comprises a threaded member extending radially through said sleeve for radial movement into or out of engagement with the head of the locking spline piece.

Other featu res of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein:-

Figure 1 is a diagrammatic part elevational, part sectional view of a shaft coupling constructed in accordance with the invention showing a locking sleeve surrounding the female shaft member in an operative position; Figure 2 is a similar diagrammatic view to that of Figure 1 but showing the locking sleeve in its inoperative position; Figure 3 is a transverse cross sectional view on the line 3-3 of Figure 1; Figure 4 is a transverse cross sectional view on the line 4-4 of Figure 2; Figure 5 is a tot plan view of the locking spline piece; Figure 6 is an end elevational view of the locking spline piece; and Figure 7 is a side elevational view of the locking spline piece.

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i i i i 1 1 1 1 1 1 -- 1 In the drawings there is illustrated, in accordance with the invention, a shaft coupling comprising a male shaft member 10 having a plurality of radially outwardly projecting axially extending splines 12 received within a female shaft member 14 having cooperating radially inwardly projecting axially extending splines 16. The two shaft members are releasably engageable with one another for torque transmission purposes as may typically be required in a drive from the power take off shaft of an agricultural tractor to an agricultural implement connected to the tractor. In such an application the male shaft member 10 would comprise the driving power take off shaft of the tractor whereas the female shaft member 14 would comprise the driven shaft attached to the implement.

The cooperating splines 12-16 on the male and female shaft members are uniformly spaced circumferentially thereof and a certain tolerance is provided as between the axially extending grooves defined between the splines 16 of the female shaft member and the splines 12 of the male shaft member which engage within such grooves whereby the two shaft members may be easily telescopically engaged and disengaged relative to one another. However, during torque transmission, it is desirable that these tolerances, which give rise to a certain amount of free play between the shaft members, are eliminated otherwise excessive noise and wear may take place between the torque transmitting flanks of the respective splines on the driving and driven members.

In accordance with the invention a separate locking spline piece 18 is located within a radially extending circular cross section through bore 20 in the female member 14 for wedging engagement between two adjacent 6 splines of the male member to eliminate the free play between said members in either direction of torque transmittal.

AS will be seen clearly from Figures 5 to 7, the spline piece 18 has a circular cross section body 22 which is received within said bore 20 in the female member and is provided with an axially extending locking spline 24 which is wedgable between two adjacent splines 12 of the male shaft member so that one flank 26 of the locking spline 24 of the separate spline piece cooperates with a corresponding one of the flanks of a pair of adjacent splines 12 of the male member. The spline piece 18 further includes a parallel sided elongate head 28 at that end of the body 22 remote.from the locking spline 24. As can be seen from Figures 3 and 4, the central longitudinally extending axis of the locking spline 24 of the spline piece is offset laterally of the central longitudinal axis of the.body 22 and of the bore 20 within which the body is received whereby said wedging action of the locking spline flank 26 against a spline flank of the male member may be accomplished.

In Figure 3 of the drawings, the spline piece 18 is shown with its locking spiine 24 wedgingly engaged against a spline flank of the male member thereby taking up the free play between the male and female members and ensuring that all of the spline flanks of the one member are brought into contact with the corresponding spline flanks of the other member 12 enabling torque transmission to be accomplished via said cooperating spline flanks. In Figure 4 of the drawings the spline piece 18 is shown partially radially withdrawn within its bore 20 out of wedging engagement with a spline flank of the male member and, in this position, it may be rotated 1 i i i i -t i i 7 through 180 degrees so that, due to the offset in the respective longitudinal axes of the spline piece 24 and the bore 20, the same flank 26 of the spline piece may then be brought Into wedging engagement with the flank of 5. a spline 12 of the male member 10 for torque transmission between the members 10 and 12 in the opposite direction.

The spline piece 18 is maintained in its wedging engagement position with a spline 12 of the male member by pressure means urging the spline piece radially inwardly of its bore 20. As is shown in Figures 1 to 4, said pressure means comprises a threaded bolt 30 received within a threaded aperture in an annular sleeve 32 surrounding the female member and being biased by a coil compression spring 34 axially of the female member 14 from an inoperative position shown in Figure 2 to an operative position shown in Figure 1. In Figure 1, the radially inner end of the bolt 30 overlies the head 28 of the spline piece 18 whereby the bolt may be screwed radially inwardly of the sleeve 32 into pressure contact with the head 28 of the spline piece to retain it in its said wedging engagement with a spline flank of the male member. When it is desired to release the spline piece 18 from its said wedging engagement position, the bolt 30 is rotated to move radialiy outwardly of the sleeve 32 and the sleeve moved axially to its inoperative position shown in Figure 2 whereby the spline piece may then be partially withdrawn radially outwardly of its bore (i.e.

to the position shown in Figure 4) and rotated through degrees as hereinbefore described for reinsertion and wedging engagement for use in torque transmission in the opposite direction.

The head 28 of the spline piece 18 is provided with projections 36 extending axially outwardly of the body 22 i 1 8 and axially of the menbers 10, 14 whereby radfally inward movement of the spline piece in its bore 20 is limited (see Figure 1). Radially outward movement of the spline piece 18 is limited by engagement of the projections 36 with the sleeve 32 (see Figure 2) when In its inoperative position with the bolt 30 retracted.

The female member 14 is further provided with two radially opposed bores 38 within each of which is received a blocking ball 40 engageable at its radially innermost position within a circumferential recess provided on the male member 10. The radially outer surface of the blocking balls are engageable by the sleeve 32 whereby, as shown in Figure 3, the blocking_ members are retained within said circumferential recess thus preventing axial separation of the male and female members. Conversely, in the inoperative position of the sleeve 32 the balls are movable to their radially outer positions as shown in Figure 4 thereby permitting axial separation of the male and female members for engagement or disengagement with one another.

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Claims

1. A shaft coupling comprising a male shaft member having a plurality of radially outwardly projecting axially extending splines; a female shaft member releasably engaged about said male member and having cooperating radially inwardly projecting axially extending splines; a separate locking spline piece located within a radially extending bore in said female member and comprising an axially extending locking spline enaaaeable between two adjacent splines of the male member, said locking spline having a flank selectively cooperable with a corresponding one of the flanks of said two adjacent splines of the male member; pressure means for urging said spline piece radially inwardly of said bore; a central longitudinally extending axis of said locking spline, being offset laterally of the longitudinal axis of said bore whereby said flank of the locking spline is wedgingly engageable under the action of said pressure means with a said corresponding spline flank of the male member restraining said male and female members against rotation relative to one another.

2. A shaft coupling as claimed in Claim 1 wherein said bore in the female member is of circular cross sectional form and the locking spline piece comprises a body portion of complimentary circular cross sectional form to that of said bore, said locking spline being provided at the radially inward end of said body portion, whereby, upon release of said pressure means, the locking spline piece may be withdrawn radially outwardly of said bore and rotated therein for selective cooperation of said locking spline flank with a said corresponding spline flank on the male member.

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3. A shaft coupling as claimed in Claim 2 wherein the locking spline piece includes a head portion at the radially outward end of said body portion, said head portion being engageable by said pressure means.

4. A shaft coupling as claimed in any one of Claims 1 to 3 further including a locking sleeve carrying said pressure means thereon and surrounding said female shaft member and being movable axially thereof, spring means being provided to bias said sleeve from an inoperative position to an operative position wherein said pressure means is engageable with said locking spline piece.

5. A shaft coupling as claimed in Claim 4 wherein a plurality of blocking members are carried within radially extending bores in said female member for engagement with a circumferential recess in said male member, said blocking members being engageable by said sleeve in its said operative position for restraining said male and female members against axial separation.

6. A shaft coupling as claimed in any one of Claims 1 to 5 wherein said pressure means comprises a screw threaded member movable radially inwardly or outwardly relative to said female m-mber.

7. A shaft coupling constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

ed 19BS at The. Patent Office. State House. 6671 High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Office. Sales Branch. St MarY Cray. Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 157.

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