GB2201223A - Friction couplings - Google Patents

Description

IMPROVEMENTS IN OR RELATING TO FRICTION LOCKINGMEANS This invention relates to locking members which secure together two components by frictional engagement between the locking member and the components, and in particular to a locking member capable of exerting both radial and axial retaining forces on said components. Locking members of the type described in British patent no 1,393,257 are generally interposed in a radial gap provided between a first component and a second component. In one application one of the components may be a shaft and the other component asleeve which requires securing to the shaft. The friction locking member consists of a ring (which may be complete or may have a radial split) which is formed in an "imperfect circle". That is to say the locking ring makes contact at spaced regions around its outer circumference with a radially outer located . component and makes contact at spaced regions around its inner circumference with a radially inner located component. The frictional engagement of the locking ring with the two components ensures that the components are locked together and cannot become uncoupled inadvertently. The above described locking member, whilst providing an adequate radial retaining force is incapable of' providing an adequate axial retaining force in certain applications. It is an object of the present invention to provide a locking member which will reduce, and possibly eliminate, the problem associated with the above mentioned locking member.. The present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a view of the locking ring which is the subject of the present invention Figure 2 is a side view of the locking ring taken in the direction of arrow A in figure 1 Figure 3 is a cross sectional view of the ring taken in the direction of arrows CC in figure 1 and illustrates the ring retaining an annular body in a housing Figures 4 and 5 illustrate two alternative designs of locking rings. Referring to figure 1 a ring 10 is provided with a radially inner surface 12 and a radially outer surface 14 and is deformed in a radial plane R from a perfect circular form such that it engages a first component 16 at discrete points 18 around its inner surface 12 -and a second component 20 at discrete points around its outer surface 14. Referring now to figures 2 and 3, the ring 10 is deformed from the radial plane R such that two or more equispaced portions 22 extend in an axial direction A on a first side 10a of said ring 10 to give the ring an axial width W. Referring now more particularly to figure 3, the first and second components 16, 20 are each.provided with radially extending surfaces 24, 2'6 and axially extending surfaces 28, 30 between which the ring 10 is positioned and are shaped and sized to communicate with each other in any desired manner. In use, the ring 10 is positioned between the first and second components 16, 20 such that its inner surface 12 and outer surface 14 contact the first and second components 16, 20 respectively, as described above and its first and second sides 10a, 10b contact the radially extending portions 24, 28 of the first and second components 16, 20 respectively. It will be appreciated that in order to provide any worthwhile radial retaining force FR on the first component 16 it will be necessary to make the unsprung breadth B of the ring 10 greater than the distance H between the axially extending portions 26, 30 of the first and second components 16, 20 between which it is positioned. An axial retaining force FA may be provided by ensuring the unsprung width W of the ring 10 is greater than the distance D between the radially extending surfaces 24, 28 of the first and second components 16, 20 respectively. In practice, it is desirable to provide a ring 10 which is not continuous and the gap 32 between the two ends of the ring 10d and 10e is sufficient to allow the ring to deform in use without the ends contacting each other. Throughout the specification. and claims therefore reference to a ring should be taken to include a ring which is not continuous. It will be appreciated that in order to position the ring 10 between the two components 16, 20 it will be necessary to reduce the outside diameter of do during fitting. This may be achieved by any conventional means and is aided by the gap 32. Referring now to figures 4 and 5, it will be appreciated that the ring 10 may be shaped in a variety of ways. Figure 4 shows a ring 10 which contacts the first component 16 at three points P around its inner edge and the second component at three points Q around its outer edge. Figure 5 illustrates an alternative shape ring 10 which contact the first and second components 16, 20 along extended portions of its inner and outer edges at M and W respectively. It will be appreciated that such an increase in the area of contact will considerably increase the retaining forces the ring 10 is capable of providing.

Claims (4)

1. A friction locking ring for frictionally engaging two relatively radially spaced components, said ring having an inner surface and an outer surface and being deformed from a perfect circular form such that it engages the first of said components at discrete points around its inner surface and the second of said components, at discrete points around its outer surface, in which the ring is provided with two or more portions which extend axially on a first side.

2. A friction locking ring as claimed in claim 1 in which the first side of said ring engages a radially extending surface of a first of said components and the remaining side of said ring engages a radially extending surface of the second of said components.

3. A friction locking ring as claimed i claim 2 in which the ring has an undeformed width which is greater than the axial.distance between the radially extending surface on said first component and the radially extending surface on said second component.

4. A friction locking ring substantially as herebefore described with reference to figure 1 to 5 of the accompanying drawings.