GB2188121A - Retaining rings - Google Patents

Abstract

In locating an annular ring 14 in an annular housing 10, a retaining ring 16 is provided which has a first radially extending portion 18 and a second axially extending portion 20 which in combination are capable of providing an enhanced retaining force when used in conjunction with a loading means 26, 40. In other embodiments the ring 16 has an L-shape or U-shape cross-section. <IMAGE>

Description

SPECIFICATION Improvements in or relating to retaining means This invention relates to an improved apparatus for locating orsealing and is particularly relevant to the location of annular rings in annular housings.

One well known method of locating annular rings in an annular housing is shown in Figure A, in which a retaining ring is fixedly attached to an extended portion of the housing and is provided with at least one portion which acts to retain the ring in the housing. Such a retaining ring may for example be attached to the housing by for example riveting or bolting. One major disadvantage ofthe above method of retaining isthatlittle or no load can be exerted on the annular ring by the retaining ring in orderto ensure a good location ofthe annular ring in the housing. A further disadvantage is that if the annular ring is ever exchanged for one of a slightly different width, then either spacing washers will be required upon re-assembly or it will be necessary to provide new bolting holes.

An alternative solution to the above mentioned problem is to ruse a bellville washer as shown in Figure B. Such a washer is shaped so that its outer edge is spaced axially from its inner edge. In operation, the washer is used in conjunction with a clamping means of any conventional form such that one edge of the washer acts against the annular ring and the other edge acts againstthe clamping means such that when a clamping load is applied bythe clamping means, the ring is deformed in such a mannerthatthe clamping load is transferred to the annular ring to retain the annular ring in the housing.

This solution, whilst overcoming the disadvantages of the above mentioned solution still suffers from a number of disadvantages.

One disadvantage of the above solution resides in the change of size of the inner and outer diameters of the washer during deformation. During deformation, the inside diametertends to reduce and the outside diametertendsto become larger. Changing inner and outer washer diameters can cause location problems and may result in an uneven load being applied to the annular ring.

Furtherto this, the amount of spring force available from the washer is severely limited by the amount of axial deformation the washer is capable of accommodating before the material is stretched beyond its elastic limit on the outer diameter or the washer is flattened.

An object of the present invention isto provide an appartusfor retaining an annular ring in a housing which reduces and possibly eliminates the disadvantages of the above two mentioned methods.

The present invention will now be particularly described with reference to the accompanying drawings, in which: Figure lisa cross-sectional view of a first type of spring ring shown in its deformed position in a typical installation.

Figure2 is a cross-sectional view of the spring ring shown in Figure 1 in its relaxed position.

Figure 3 is a cross-sectional view of a second shape of spring ring positioned in a second installation.

Figure 4 is a cross-sectional view of a third shape of spring ring positioned in a third installation.

Referringto Figure 1,an annularhousing 10 is provided with a recess 12 into which an annular ring 14 is positioned. The spring ring shown generally at 16 comprises one generally radiallyextending portion 18 and one generally axially extending portion 20. A clamping means, shown generally at 22 comprises a second annular ring 24which is urged into contact with the annular housing 10 by a plurality of nuts 26 and bolts 28 circumferentially spaced around the ring 24 and housing 10. The second ring is provided with a recess at 30 having an end face 32. In operation, the generally radially extending portion 18 of the spring ring 16 is deformed axially whilst the generally axially extending portion 20 is deformed radially to provide a retaining force capable of retaining the annular ring 14 in the housing 10.Deformation of the spring ring 16 is achieved by tightening the nuts and bolts 26,28 such that the end face 32 of the recess acts on the free end 34 of the axially extending portion 20 and hence urges the radially extending portion 18 into contact with the annular ring 14. Furthertightening ofthe nuts and bolts 26,28 will increase the deformation of the spring ring 16 such that the axially extending portion 20 isforced up againstthe radially inwardly facing face 36 of recess 30. Any additional tightening of the nuts and bolts 26,28 will theteafter result in axial deformation of the radially extending portion 18.

In such a deformed position, the spring ring will exert a force F1 on the annular ring 14 and F2 on the second annular ring 24 which in combination act to resist the axial and circumferential movement of the annular ring 14.

It has been found that the addition of the axially extending portion 20 greatly increases the retaining force which is exertable on the annular ring 14for a given axial displacement of the radially extending portion. Further to this, the outside diameter of the spring ring 16 is restrained by the inside diameter of the second ring 24, this aids location of the ring and assists in providing an even retaining force.

Turning now to Figure 2, it will be seen that when the ring is relaxed the axially extending portion 20 extends along a plane which is substantially parallel to the longitudinal centre line 42 of the ring 16 to aid assembly and the radially extending portion 18 is angled relative to the radial plane 45 by an amount 0.

It will be appreciated that other angles could be used.

A second shape of spring ring 16 is shown in Figure 3. The ring is substantiallythe same shape as that shown in Figures 1 and 2 exceptforthe addition of a loading flange 38 at one end ofthe axially extending portion 20 In its relaxed position the radially extending portion 18 is bent towards the axially extending portion 20. A nut 26, bolt 28 and loading tab 40 are provided on the housing 10 and are positioned to communicate with the loading flange 38.

In operation, the nut 26 and bolt 28 are progressively tightened such that the loading tab 40 and loading flangeare pulledtowardsthe housing 10 in the direction of arrow 5. This in turn brings the radially extending portion 18 into contact with the ring 14. Furthertightening ofthe nuts and bolt 26,28 will result in a progressively larger retaining force being extended on the ring 14. The spring ring 16 may be shaped and positioned such that the axially extending portion comes into contact with the housing 10 when loaded, thus increasing the retaining force.

Referring now to Figure 4, a third shape of spring ring 16 comprises two generally radially extending portions 42,44 and one generally axially extending portion 46 which acts to join the two portions 42,44 together. Each portion is angled from the radial plane 45 by an amountl2i.The housing loins provided with a retaining flange 54 at one end and a threaded portion 58 at another which cooperates with a similarly threaded retaining ring 48.

In operation, the retaining ring 48 is tightened down the thread 58 such that the spring ring 16 is deformed and a retaining force exerted on the annular ring 14.

Itwill be appreciated that the annular ring 14 may take any form, such as for example a brush seal of the type described in British Patent No. 1,450,553.

A pair of such seals are shown in Figure 4at50 and 52. In operation, the inside edge of the brush seal 50 52 act against the outside diameter ofthe shaft 56to effect a seal.

It will also be appreciated thatthe spring rings 16 described in this specification may be used as seals, in which the ring 16 acts to prevent a fluid or gas from leaking past the ring 16.

Claims (5)

1. A ring for use in combination with a clamping means to retain a body in a housing, said ring having a generally radially extending portion, which in operation is urged against the body by the action of the clamping means and being provided with a generally axially extending portion.

2. A ring according to claim 1 in which the generally extending portion is deformed axially and the generally axially extending portion is deformed radially by the action of the clamping means.

3. A ring according to either of the preceding claims in which the generally axially extending portion is provided with a free end against which the clamping means acts.

4. A ring according to claim 1 or claim 2 in which a second generally radially extending portion is provided against which the clamping means acts.

5. A ring substantially as herein described with referenceto Figures 1 to 4 of the accompanying drawings.