GB2259740A - A method of forming a composite seal - Google Patents

Abstract

A method of forming a composite seal is provided in which a channel (3) is formed by channel defining walls (4, 5) in a carrier element (1). A seal (6) has its edge (7) inserted into the channel (3) and the walls (4, 5) are pressed together by a crimping tool (8) to grip the seal (6). In this way the seal (6) is retained by the camper (1) without the requirement for an inner retaining shell. <IMAGE>

Description

A METHOD OF FORMING A COMPOSITE SEAL This invention relates to a method of forming a composite seal.

Composite seals have been produced from pressed steel components comprising inner and outer shells between which are placed a gasket and a seal. The shells are arranged to compress the seal against the gasket to prevent leakage of lubricant past the seal and to retain the seal in position. Each composite seal therefore comprises four major components.

According to the invention there is provided a method of forming a composite seal comprising providing a sealing element and a carrier element, forming a channel in the carrier element, inserting an edge of the sealing element into the channel and pressing the channel defining walls together to grip the sealing element therebetween.

By gripping the sealing element with the walls of the channel the need for an inner shell is eliminated. Further the walls may be deformed to such an extent that no lubricant can leak past the edge of the sealing element in the channel eliminating the requirement for a gasket. A method according to the invention thus provides a composite seal with significantly fewer parts making the seal cheaper to produce.

By pressing, it is meant the application of pressure to one or both of the walls to close the channel, at least, partially. The pressing operation may be carried out a crimping tool or in a rolling or spinning operation in which a roller is applied to one of the walls and the carrier element rotated. A force is applied by the roller to press the walls together.

A specific embodiment of the invention will now be described, by way of example only, with reference to the drawings in which: Figure 1 shows the stages in producing a composite seal according to the invention; and Figure 2 shows the completed composite seal.

Figure l(a) shows the first stage of making a composite seal in which a one piece pressed steel shell 1 is formed as an annulus having an aperture 2 to permit insertion of a shaft. The shell is generally 'L' shape in section having an inner end folded to form a channel 3 defined by walls 4 and 5.

As shown in Figure l(b), an annular shaft seal 6 of PTFE (polytetrafluoroethylene) material has its edge 7 inserted into the channel 3. With the seal 6 maintained in position, a crimping tool 8 is applied to wall 4 of the channel 3 whilst an outer wall 9 of the carrier is supported by a block 10 as shown in Figure l(c). The walls 4 and 5 of the rebate 3 are thus squeezed together compressing the seal 6 and causing a bulge 10 of seal material which substantially fills the channel 3 as shown in Figure 2. In use the composite seal is mounted about a shaft 11 by inserting the shaft 11 through a central hole of the shaft seal 6. The hole is of a diameter which is slightly smaller than that of the shaft 11 and insertion causes distortion of the seal 6 into sealing contact with the shaft 11.

Claims (4)

1. A method of forming a composite seal comprising providing a sealing element and a carrier element, forming a channel in the carrier element, inserting an edge of the sealing element into the channel and pressing the channel defining walls together to grip the sealing element therebetween.

2. A method as claimed in claim 1 wherein the walls are pressed together until the sealing element substantially fills the channel.

3. A method of forming a composite seal substantially as hereinbefore described with reference to and as illustrated by the drawing.

4. A composite seal is substantially as hereinbefore described and as illustrated by the drawing.

4. A composite seal is substantially as hereinbefore described and as illustrated by the drawing.

Amendments to the clans have been filed as follows 1. A method of forming a composite seal comprising providing a sealing element and a carrier element, forming a channel in the carrier element by a folding operation, inserting an edge of the sealing element into the channel and pressing the channel defining walls together to grip the sealing element therebetween.

2. A method as claimed in claim 1 wherein the walls are pressed together until the sealing element substantially fills the channel.

3. A method of forming a composite seal substantially as hereinbefore described with reference to and as illustrated by the drawing.