GB2145483A

GB2145483A - Leakproof sealing washer

Info

Publication number: GB2145483A
Application number: GB08418837A
Authority: GB
Inventors: Reginald Charles Bull; Harold Albert Drew
Original assignee: ASHTON Ltd THOMAS A; BULL RUBBER Co Ltd RC
Current assignee: ASHTON Ltd THOMAS A; BULL RUBBER Co Ltd RC
Priority date: 1983-08-24
Filing date: 1984-07-24
Publication date: 1985-03-27
Also published as: GB8418837D0; GB8322782D0; GB2145483B

Abstract

Leakproof sealing washer comprises a metal washer (18) and a resilient sealing washer (20) snap fitted in position within the metal washer. So that a leakproof connection can be effected, the arrangement is such that when the washer is in use, radially outwardly projecting portions (26) of the sealing ring (20) which are located in annular grooves (24) of the metal washer (18) are locked therein. <IMAGE>

Description

SPECIFICATION Leakproof sealing washer The invention relates to leakproof sealing washers of the kind comprising a resilient sealing ring located within a metal washer.

In particular, such washers are used when making high pressure hydraulic connections into items such as pumps, hydraulic motors, machine tools, engine fuel systems and the like. So-called "bonded" seals have been available for many years in which the resilient sealing ring is permanently bonded within the metal washer, the latter usually being either a cadmium plated or similarly treated steel washer, a stainless steel washer or an aluminium alloy washer depending upon the intended application. It is now thought desirable to provide a leakproof sealing washer of the kind referred to in which the resilient sealing ring is simply snap fitted in position within the metal washer so that when it is desired to replace such a sealing washer the metal component can be retained and the old resilient sealing ring simply exchanged for a new one.

However, since the resilient sealing ring is not to be bonded within the metal washer there could then be a danger of leakage of hydraulic fluid, under very high pressure, along the crevice between the two components of the sealing washer.

The object of the invention is to provide a leakproof sealing washer in which the resilient sealing ring is snap fitted within the metal washer, the arrangement being such that the danger referred to is virtually eliminated.

According to the invention, there is provided a leakproof sealing washer comprising a metal washer and a resilient sealing ring snap fitted in position within the metal washer, a sealing surface within the metal washer being undercut adjacent the opposite planar faces of the washer to provide annular grooves in the opposite faces of the washer, the cross sectional shape of the resilient sealing ring being complementary to the shape of the bore of the metal washer but in addition having end portions which in the free unstressed condition of the sealing ring stand proud of the planar faces of the metal washer, the arrangement being such that, when the leakproof sealing washer is in use, the end portions of the sealing ring are passed flat into co-planar relation with the planar faces of the metal washer, radially outwardly projecting portions of the sealing ring which are located in the annular grooves of the metal washer being locked therein and the compression of the resilient material of the ring brought about by the pressing flat of the outwardly projecting portions of the ring producing, in effect, a nipping of circumferentially extending portions of the sealing ring which acts to combat any tendency for leakage to occur through the crevice between the two parts of the sealing washer. The end portions of the sealing ring which in its unstressed condition stand proud of the planar faces of the metal washer will preferably be of frusto-conical shape. The seating surface within the metal washer will preferably be of partly concave shape in cross section.The annular grooves in the opposite faces of the metal washer which cause parts of the sealing ring to be locked therein when in use will preferably be of V-shape in cross section.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a sectional view illustrating the use of a leakproof sealing washer embodying the invention, Figure 2 is a sectional view of the sealing washer drawn to a very much larger scale than Figure 1, and Figure 3 is a view similar to Figure 2 but illustrating the manner in which the sealing washer is deformed when in use.

Referring now to Figure 1, the high pressure hydraulic connection there illustrated comprises a screwthreaded adaptor member 10 in threaded connection with some item of equipment 12. The adaptor member 10 has a hexagonal portion 14 to which a wrench can be applied, and a leakproof sealing washer generally indicated 1 6 embodying the invention is located between a joint face of the item of equipment 1 2 and the abutment shoulder provided by the hexagonal portion 14.

In Figure 2 there is illustrated the construction of the leakproof sealing washer 16, this comprising a metal washer 1 8 of generally rectangular cross section and a resilient sealing ring 20 snap fitted in position within the metal washer. However, the seating surface 22 within the metal washer and which surrounds the central portion of the resilient sealing ring, although being of mainly concave shape in cross section, as shown, is undercut adjacent the opposite planar faces of the washer, providing annular grooves 24 in the opposite faces of the washer (the annular grooves in the washer illustrated being Vshaped in cross section).The cross sectional shape of the resilient sealing ring is complementary to the shape of the bore of the washer just described but in addition has frusto-conical end portions 26, as shown, which in the free unstressed condition of the sealing ring stand proud of the planar faces of the washer. The resilient sealing ring has a plain cylindrical bore except for the provision of a shallow inwardly projecting circumferential ridge 28 midway between its ends, this being provided solely for the purpose of restricting movement of the sealing washer during assembly, that is to say initially locating the leakproof washer substantially co-axially of the screwthreaded adaptor member.

The arrangement is such that when in use the sealing washer is deformed as shown in Figure 3, that is to say, the frusto-conical end portions 26 of the sealing ring are pressed flat into co-planar relation with the planar faces of the metal washer. In addition, the radially outwardly projecting portions of the ring which are located in the annular grooves 24 are locked therein, and the compression of the material of the ring brought about by the pressing flat of the portions 26 produces, in effect, a nipping of the narrower parts of the ring, that is to say in those regions indicated 30 in Figure 3.Consequently, although the two separate parts of the leakproof washer are merely snap fitted together instead of being bonded together it is thought that there can be no danger of leakage occuring through the crevice between the two parts of the sealing washer even under conditions of very high hydraulic pressure. It will in fact be understood that the greater the pressure acting within the bore of the resilient ring and the greater will be the pressure with which its end portions act against the metal surfaces between which the washer is clamped (and indeed the greater will be the nipping effect produced in the regions 30).

Various modifications may be made. For example, the circumferential ridge 28 midway between the ends of the bore of the resilient sealing ring could quite well be replaced by some other shape of localised ridge, or in fact be a discontinuous ridge constituted by a number of ridge segments. Furthermore, the metal washer 1 8 need not necessarily be of generally rectangular cross section; it must of course have surfaces co-planar with those of the metal surfaces between which the finished washer is to be clamped, but its outside diameter need not be cylindrical but could for example be curved in cross section. The annular grooves in the opposite faces of the metal washer which cause parts of the sealing ring to be locked therein when in use need not necessarily be of V-shape in cross section; they could be of a rectangular or other flat bottomed shape (but must of course still be arranged to undercut to some extent the central part of the seating surface within the metal washer).

Claims

1. A leakproof sealing washer comprising a metal washer and a resilient sealing ring snap fitted in position within the metal washer, a sealing surface within the metal washer being undercut adjacent the opposite planar faces of the washer to provide annular grooves in the opposite faces of the washer, the cross sectional shape of the resilient sealing rihg being complementary to the shape of the bore of the metal washer but in addition having end portions which in the free unstressed condition of the sealing ring stand proud of the planar faces of the metal washer, the arrangement being such that, when the leakproof sealing washer is in use, the end portions of the sealing ring are pressed flat into co-planar relation with the planar faces of the metal washer, radially outwardly projecting portions of the sealing ring which are located in the annular grooves of the metal washer being locked therein and the compression of the resilient material of the ring brought about by the pressing flat of the outwardly projecting portions of the ring producing, in effect, a nipping of circumferentially extending portions of the sealing ring which acts to combat any tendency for leakage to occur through the crevice between the two parts of the sealing washer.

2. A leakproof sealing washer according to claim 1, in which the end portions of the sealing ring which in its unstressed condition stand proud of the planar faces of the metal washer are of frusto-conical shape.

3. A leakproof sealing washer according to either one of the preceding claims, in which the seating surface of the metal washer is of partly concave shape in cross section.

4. A leakproof sealing washer according to any one of the preceding claims, in which the annular grooves in the opposite faces of the metal washer which cause parts of the sealing ring to be locked therein when in use are of V-shape in cross section.

5. A leakproof sealing washer constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.