Metal working – Method of mechanical manufacture – Assembling or joining
Patent
1996-11-27
1999-03-30
Bryant, David P.
Metal working
Method of mechanical manufacture
Assembling or joining
2988804, 292835, 277 9, B23P 1100, B23Q 300, F16K 1500
Patent
active
058873309
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to seals and a method and apparatus for fastening a seal in place in a groove.
It is known to fasten an annular shaft seal to a support body by positioning an edge of the seal in a groove and then crimping a lip forming a wall of the groove so as to grip the edge of the seal. This crimping is undertaken using a die which moves laterally of the lip. This known crimping technique can result in cracking of the lip, which can lead to mechanical failure and leakage.
The present invention provides a method of fastening a seal in a groove in which a lip forming a wall of the groove is deformed so as to grip an edge of the seal in the groove, the lip being deformed by a pressing tool having at least one ball roller, said at least one ball roller moving along the length of the lip so that the centre line of said at least one ball roller parallel with the tool axis is offset from the lip to produced a chamfered pressed lip. The ball roller(s) can be moved relative to the lip, or vice versa.
The invention is especially applicable to an annular seal which is fitted into an annular groove in which case the ball roller is moved in a circular path. Preferably, a plurality of spaced-apart ball rollers are used which are located around said circular path.
The present invention also provides a pressing tool for fastening a seal in an annular groove in a support body, the tool comprising a rotatable holder carrying a plurality of ball rollers which run along a common circular path around the groove when the holder is rotated in contact with the support body, in which in use the ball rollers run around and deform a lip forming a wall of the groove so as to grip an edge of the seal, the pressing tool being applied in use so that the centre line of each said ball roller parallel with the tool axis is offset from the lip to produce a chamfered pressed lip. To effect the rotation, either the holder or the support body, or both, can be moved.
The ball rollers of the pressing tool are preferably spaced circumferentially around the periphery of a circular crosssection holder that is rotatable around its central longitudinal axis.
The ball rollers can be carried on the holder by legs which project from a front face of the holder. The legs may be biased to ensure good contact and relatively uniform pressure on the support body. The biasing can be spring-loading, electromagnetic or pneumatic loading, or loading using a gasfilled cavity.
The legs may include grease channels to the ball rollers for lubricating them. A grease channel in a spring-loaded leg may include a valve so that as the ball roller abuts and presses the support body against the force of the loading, grease is forced onto the ball roller. Thus lubrication of the ball rollers is effected automatically.
A preferred embodiment of the invention will now be described, by way of example, and with reference to the drawings, in which:
FIG. 1 is a diagrammatic cross-sectional view of a tool according to the present invention for securing an annular seal to a metal body so as to project radially inwards therefrom;
FIG. 2 is a front view of a first embodiment of a pressing tool according to the present invention;
FIG. 3 is a sectional view along the line X--X shown in FIG. 2;
FIG. 4 is a front view of a second embodiment of a pressing tool according to the present invention;
FIG. 5 is a cross-sectional view along the line X--X as shown in FIG. 4;
FIG. 6 is a front view of a third embodiment of a pressing tool according to the present invention; and
FIG. 7 is a cross-sectional view along the line X--X shown in FIG. 6.
As shown in FIG. 1, an annular shaft seal 6 is fastened to a support body 4' by inserting an edge of the seal 6 in a groove 5 in the support body 4' then crimping a lip 4 which forms a wall of the groove 5 so as to grip the edge of the seal 6. The crimping is performed by a ball roller 22 moving along the length of the lip 4 and groove 5. The point of engagement of the ball roller 22 with the lip 4 is offset to one side of the centre lin
REFERENCES:
patent: 2792625 (1957-05-01), Hoffman
patent: 3395441 (1968-08-01), Herbenar
patent: 3793699 (1974-02-01), Merola
patent: 3863740 (1975-02-01), Kinman
patent: 5267736 (1993-12-01), Pietsch et al.
patent: 5373819 (1994-12-01), Linder
patent: 5419032 (1995-05-01), Rytych
Cole David Alexander
Everett Richard Mervyn
Bryant David P.
Dowty Seals Limited
Stewart Tisa
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