CA2219918A1

CA2219918A1 - Shaft coupling

Info

Publication number: CA2219918A1
Application number: CA002219918A
Authority: CA
Inventors: David Thomas Wormall; Michael Thomas Hancock
Original assignee: Nastech Europe Ltd
Current assignee: Individual
Priority date: 1995-05-31
Filing date: 1996-05-30
Publication date: 1996-12-05
Also published as: EP0828647A1; KR19990022120A; JPH11505917A; BR9608864A

Abstract

A shaft coupling includes a shaft (1) with a circumferential groove (2) near one end, a shaft receiving member (3) and a resiliently loaded shaft retention member (4) in the shaft receiving member (3). The shaft retention member (4) can be reciprocated in an elongate slot with or against the resilient bias so that upon insertion of the shaft in the shaft receiving member the shaft retention member (4) snaps into engagement with the groove (2) in the shaft (1). Any tendency to draw the shaft out of the shaft receiving member causes the shaft retention member to bed more firmly in the groove (2). In an alternative arrangement, the shaft retention member can be a torsion spring (9) fitted about a clamping bold (4), with one end (9A) of the spring engaging in the groove (2) of the shaft. The shaft (1) can be a vehicle steering column shaft and the shaft receiving member (3) can be a yoke of a universal joint.

Description

~ ;7 ' '~'';

~HAFT COUPLING

This invention relates to a shaft coupling. More particularly, the invention relates to a snap retention coupling between a vehicle steering column and a universal joint.

In the past, various methods have been applied to coupling steering column shafts with universal joint yokes and most lo o~ these provide a permanent connection. A typical sha~t coupling is shown and described in GB-A-2 124 739.

With detachable connections, it has been the practice to insert the shaft into the yoke and then to fit a bolt to clamp the yoke around the sha~t However, where the coupling is one where the sha~t end is splined and is inserted into a splined bore in the yoke, i~ the sha~t has not been inserted in the yoke su~iciently ~ar, then tightening of the bolt will cause the clamping ef~ort to be applied on the splines. There is then the risk that the splines in use can become worn or fretted so that, in perhaps one or two years' time, there is a risk of the shaft being able to rotate and there~ore not to transmit steering motion.
According to the present invention, there is provided a sha~t coupling comprising a shaft receiving member having a transversely extending aperture therethrough and a shaft receiving bore therein; a sha~t having a groove in its circum~erence, the shaft being insertable into the sha~t receiving bore; and a retention means ~or biasingly engaging the sha~t groove to retain the sha~t in the shaft receiving member; characterised in that the retention means includes a transversely extending pin member within the sha~t receiving aperture.

Ah~ENDED S~tEET

. . . . - . . . ' .. -;

' Preferably, the end of the shaft in the region of the ~ ~roove is splined, the spi,nas of the shaft engaging in corresponding splines of a shaft receiving bore of the shaft receiving member. It will be appreciated that other shapes of cross-section can be utilised, e.g. triangular, to permit transmission of rotary force.

Preferably, the pin member is a bolt which can be tightened when it is in engagement with the shaft in the shaft receiving member.

The invention has particular applicability where the shaft is a vehicle steering column shaft and where the shaft receiving member is a yoke of a universal joint.
For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which:-Figure 1 is a diagrammatic side view of a shaft couplingshowing a vehicle steering column shaft prior to retention in a universal joint yoke, Figure 2 is an end view showing the rear face of the yoke shown in Figure 1, Figure 3 is a plan view of the yoke shown in Figure 1, Figure 4 shows an alternative construction to hold the torsion spring in place, and Figure 5 is a diagrammatic view of the torsion spring itself.

AME~D~D S~ET

The drawing shows one end of a vehicle steering column -- shaft, which has splines lA. A circ~mferential groove 2 is provided in the shaft near the end lB of the shaft 1 and interrupting the splines lA. The groove 2 could be in the form of a flat. A shaft receiving member is in the form of a slotted yoke 3 of a universal joint ~or the steering column, the yoke 3 being provided with a splined through-bore 3A to receive the splined end of the shaft 1.
Interaction of the splines on the shaft and in the bore facilitate mutual rotation of shaft and yoke.

To facilitate retention of the shaft 1 in the bore 3A, a resiliently-loaded shaft retention means is provided. This takes the ~orm o~ a pin member in the ~orm of a clamp bolt 4 and torsion spring 9 which are located in the yoke 3.

The torsion spring 9, as best seen in Figure 5, includes a barbed end 9A for engaging the groove or flat 2, a central coiled portion 9B for location about the bolt 4 and a bent other end portion 9C for engagement under its own resilient pressure against an outer surface of the yoke 3 in order to prevent the torsion spring 9 from rotating.

In an alternative arrangement illustrated in Figure 4, the end 9C of the torsion spring 9 is held in a retention groove 3B in the yoke 3.

In use, as the shaft 1 enters the bore 3A of the yoke 3, the barbed end 9A of the torsion spring 9 is flexed upwards as viewed in Figure 1 until the shaft 1 is pushed sufficiently far in for the end 9A to snap into the groove 2.

A~ S~

" CA 02219918 1997-10-30 ,' ','';;

' The barbed end 9A of the torsion spring 9 l'ocks into the . groove 2 upon any,te~ency for the shaft and yoke to be pulled apart.

The yoke 3 is provided with a bore 3C to receive the bolt 4 and Figure 3 shows that the torsion spring 9 is housed in a slotted part 3D of the yoke 3.

In the embodiment illustrated, it will be appreciated that the constructions provide a shaft to yoke connection that will fit together easily but will not pull apart and so will ensure that correct spline/shaft penetration is made before the bolt is tightened. When correct penetration has been reached, the operator cannot pull the shaft out and so the operator then knows there is correct positioning for the yoke to be clamped about the shaft by tightening the bolt 4.

~N~0 S~

Claims

CLAIMS:

1. A shaft coupling comprising a shaft receiving member (3) having a transversely extending aperture therethrough and a shaft receiving bore (3A) therein, a shaft (1) having a groove (2) in its circumference, the shaft being insertable into the shaft receiving bore (3A), a retention means for biasingly engaging the shaft groove to retain the shaft in the shaft receiving member, the retention means includes a transversely extending pin member (4) within the shaft receiving member aperture, and a spring (9);
characterised in that said spring is a torsion spring (9) located in said shaft receiving member (3) and prevented from rotation in one direction, said torsion spring (9) having a part for engagement in said groove (2) and being wound around the pin member, which is a clamping bolt (4) provided to clamp said shaft receiving member onto said shaft when said spring is urged into said groove (2) of said shaft (1).

2. A shaft coupling according to claim 1, wherein the end of said shaft (1) in the region (1A) of said groove (2) is splined, the splines of the shaft engaging when coupled in corresponding splines of the shaft receiving bore (3A) of said shaft receiving member (3).

3. A shaft coupling according to claim 1 or 2, wherein said pin member is a bolt (4) which can be tightened when it is in engagement with said shaft (1) in said shaft receiving member (3).

4. A shaft coupling according to claim 3, wherein the angular relationship between said elongate slot (5) and the direction of entry of said shaft (1) into said shaft receiving-member (3) is such as to prevent the shaft from being pulled out of said shaft receiving member by causing one end of said torsion spring (9) to be urged into said groove (2) upon application of force to draw said shaft out of said shaft receiving member.

5. A shaft coupling according to any one of the preceding claims, wherein said shaft is a vehicle steering column shaft.

6. A coupling according to any one of the preceding claims, wherein said shaft receiving member is a yoke (3) of a universal joint.

7. A vehicle incorporating a shaft coupling according to any one of the preceding claims.