GB2133840A

GB2133840A - Transportation and fitting ring for a radial lip seal and a material for use in relation thereto

Info

Publication number: GB2133840A
Application number: GB08301293A
Authority: GB
Inventors: Charles William Potter
Original assignee: JH Fenner and Co Ltd
Current assignee: JH Fenner and Co Ltd
Priority date: 1983-01-18
Filing date: 1983-01-18
Publication date: 1984-08-01
Also published as: GB8301293D0; GB2133840B

Abstract

A transportation and fitting ring (12) for applying a radial lip seal (11) to a shaft (22) is formed of a resiliently flexible flat strip material having a thin edge region (16) displaced so that its inner face (18) is substantially in alignment with the outer face (19) of the remainder part (17) of the strip material, the outer face (24) of a transition region (20) between the edge region (16) and the remainder part (17) providing a guide surface for the sealing lip (15) of the seal (11) and the inner surface of the transition region (20) providing an abutment (21) for the end face (23) of the shaft (22). <IMAGE>

Description

SPECIFICATION Transportation and fitting ring for a radial lip seal and a material for use in relation thereto The invention concerns a transportation and fitting ring or sleeve (hereinafter referred to as a ring) and has more particular reference to a ring for application to a seal arrangement to protect the same against damage or distortion during transportation and to facilitate the fitting of the seal arrangement to a shaft or the like, and to a stock material for use in relation thereto.

It is known in the art to provide a transportation and fitting ring coaxially with and inwardly of the sealing lip of a radial lip seal, the ring being of machined or pressed metal section or moulded from synthetic thermoplastics material. Whilst the metallic ring is satisfactory in use, its manufacturing cost is such as to prompt, for reasons of economy, recovery of the ring on fitting of the seal and subsequent re-use of such ring.

The moulded rings are of sufficiently low cost as to be discarded after use, but such rings do present problems not encountered in connection with the metal rings. Thus, for example, the radial loading applied to the ring from the garter spring of the seal has the effect, in time, of reducing the dimensions of the ring, with the result that such ring may be too small to be of assistance in fitting the seal to the shaft to which such seal is to be applied. Indeed, inadequately restrained radial loading on the seal lip over an appreciable period of time, such as would follow from shrinkage of a moulded ring, may well have a deleterious affect on the seal in that the lip thereof may assume a dimension materially different from the nominal dimension thereof thus adversely affecting the sealing characteristics of the seal.

The object of the invention is to provide a transport and fitting sleeve which is sufficiently inexpensive in manufacture as to be discarded after a single use, and which furthermore, avoids the problem inherent in conventional moulded sleeves as regards shrinkage.

According to the present invention there is proposed a strip material for use in the formation of a transportation and fitting ring for a lip seal comprising a flat elongate body of a resiliently flexible material, the said body having a stepped edge region thereto of which one face is in substantial alignment with the opposite face of the remainder of the body, the region of transition between the edge region and the remainder of the body providing a cam surface at one face of the strip material, being that face of the body towards which the edge region is effectively displaced in defining the stepped edge region, and an abutment, for example, a step shoulder, at the opposite face of the region of transition.

The invention also includes the combination of a radial lip seal and a transportation or fitting ring formed from strip material as aforesaid, the length of the strip material being such as to hold the sealing lip of the lip seal at a diameter substantially equal to that of the shaft to which the seal is to be applied.

The invention will now be described further, by way of example only, with reference to the accompanying drawings illustrating several embodiments thereof, and in which: Fig. 1 is a scrap side elevation, partly in section, of a radial lip seal having a transportation and fitting ring applied thereto applied to a shaft end; Fig. 2 shows a cross-section of the material of the transportation and fitting ring drawn to a larger scale; Fig. 3 is a view taken in the direction of arrow X of Fig. 1; Figs. 4 to 7 show alternative end abutments to that of the arrangement shown in Figs. 1 to 3; and Fig. 8 shows an alternative, and preferred, fitting ring cross section and cooperating attachment clip.

Referring now to the drawings, and particularly to Fig. 1 thereof, a radial lip seal 11, for example of the kind disclosed in our co-pending United Kingdom Patent Application No. 7944248 is provided with a transportation and fitting ring 12 radially inwardly thereof, the ring 12 being produced from an extruded section of synthetic thermo-plastics material and the strip from which the ring is formed being of such length and crosssection that the ends 13, 14 thereof abut, the ring maintaining the sealing lip 1 5 of the radial lip seal 11 at a diameter equal to or marginally less than the nominal diameter of the shaft to which the seal is to be applied by virtue of the elastic properties of the synthetic thermo-plastics material.The preferred material of choice is polyethylene, but alternative materials having appropriate physical properties may be used if preferred.

As will readily be appreciated, in the event of shrinkage of the transportation and fitting ring with passage of time, the abutting ends of the strip will simply separate, the resilience of the material of the strip holding the ring at its intended diameter. Accordingly, not only will the sealing lip 1 5 of the radial lip seal 11 be held at its intended nominal dimension, but so too will the diameter of the ring 12 remain unchanged.

As can be seen from Fig. 2, the material from which the ring is formed is of flat crosssection, that edge region 1 6 thereof intended for engagement with the shaft end being of reduced thickness and being displaced relative to the body 1 7 of the strip such that one face 18 thereof is in substantial alignment with the opposite face 1 9 of the body. The transition region 20 between the reduced thickness edge 1 6 and the body 1 7 of the strip is generally of uniformly tapering crosssection and includes a step or shoulder 21 for abutment with the end of the shaft. As an alternative to the step or shoulder, other formations of like effect, that is to say formations which define an abutment, may be preferred.

In applying the radial lip seal to a shaft, the larger diameter bore to the ring as defined by the displaced edge region of the strip is engaged with the end of the shaft 22, the shoulder 21 abutting the end face 23 of the shaft, and the seal is moved across the ring in the axial direction thereof, and onto the shaft, the outer surface 24 of the transition region 20 acting as a cam surface temporarily to enlarge the inner diameter of the sealing lip 1 5 to the diameter of the outer surface 25 of edge region 16 of the ring, for passage thereacross, the reduced thickness of such region minimising the extent to which the sealing lip diameter is enlarged. The fitting ring can now be discarded.

Whilst, in the embodiment shown in Figs. 1 to 3, the ends of the strip which defines the ring are cut perpendicularly to the longitudinal axis of the strip, as is apparent at 26 in Fig. 1, the invention is not limited to such configuration, since the stability of the ring is improved by so forming the ends as to provide for relative movement therebetween in the axial direction of the strip whilst precluding relative movement in the lateral direction.

Typical strip end configurations are shown in Figs. 4 to 7, the various formations provided each including tongue and slot arrangements 27, 28 adapted to maintain longitudinal alignment between the ends, whilst the Fig. 5 embodiment further provides cooperable opposed shoulders 29, 30 for limiting the extent of relative longitudinal movement between the strip ends.

Alternative strip cross-sections and end formations to those particularly illustrated, whether adapted specifically to maintain longitudinal alignment or otherwise, may be adopted if preferred.

A preferred structure is shown in cross-section in Fig. 8 and will be seen to include a bead 31 at the intended "inner" face of the ring and adjacent the outer edge 32 thereof slidably to receive an attachment clip 33 into cooperative engagement therewith, the clip 33 bridging the abutting ends of the strip and maintaining alignment of the adjacent ends thereof on relative movement between such ends in the longitudinal direction of the strip.

We have found that, by means of the transportation and fitting ring hereinproposed we are able to avoid the problems inherent in conventional structures provided for a like purpose, both as regards the economic and technicai difficulties met with in relation to such structures.

The invention is not restricted to application in the context of radial lip seals which include a garter spring, and is of value in the transportation, storage and fitting of radial lip seals at large.

Claims

1. A transportation and fitting ring formed of a strip material, said strip material comprising a generally flat elongate body of a resiliently flexibie material, said body having a displaced edge region thereto at which one face is in substantial alignment with an opposed face of a remainder part of said body, and having a transition region between said edge region and said remainder part having opposed surfaces, one of said opposed surfaces providing a guide surface at one face of said body, being a face of said body towards which said edge region is displaced, and the other of said opposed surfaces providing an abutment.

2. A transportation and fitting ring as claimed in claim 1 wherein said edge region is thinner than said remainder part.

3. A transportation and fitting ring as claimed in claim 1 or claim 2 of polyethylene.

4. A transportation and fitting ring as claimed in any one of claims 1 to 3 wherein said strip material has ends which are perpendicular to the longitudinal axis of said strip material.

5. A transportation and fitting ring as claimed in any one of claims 1 to 3 wherein said strip material has opposed ends having cooperating formations thereon adapted to provide, when mutually engaged, for relative movement therebetween in the longitudinal direction of said strip material whilst precluding relative movement therebetween in a direction laterally thereof,

6. A transportation and fitting ring as claimed in claim 5, wherein said cooperating formations comprise one or a plurality of tongues and slots.

7. A transportation and fitting ring as claimed in claim 6 wherein said cooperating formations include cooperable opposed shoulders operable to limit the extent of said relative longitudinal movement.

8. A transportation and fitting ring as claimed in any one of claims 1 to 4 wherein an edge of said remainder part remote from said edge region has at least one bead provided thereon, at least in the region of the ends of said strip material, and including an attachment clip adapted to slidably engage the or each bead.

9. A transportation and fitting ring as claimed in any one of claims 1 to 8, in operative combination with a radial lip seal for use with a shaft of predetermined diameter, said strip material being of a length whereby a sealing lip of said lip seal is held by said ring at a diameter substantially equal to said predetermined diameter.

10. A transportation and fitting ring substantially as hereinbefore described with reference to and as illustrated in any one of Figs. 1 to 8 of the accompanying drawings.