Patent GB-582070-A (GB)
Title: Methods of and means for expanding rings
IPC: B23P15/06
Filed: 1944-07-19
Abstract: 582,070. Expanding split rings. MURRAY, W. July 19, 1944, No. 13864. [Classes 83 (ii) and 83 (iv)] Curving.-Elastic split rings for use as metallic sealing piston or bearing rings &c. are expanded by supporting them at each end of a chord and exerting pressure on an end portion between the supports to flatten or increase the radius of curvature While simultaneously rotating the ring and thereby subjecting it progressively to the flattening pressure. The ring may be supported on rollers 4 and acted on by a wheel 6 provided with a rubber rim 10 and mounted on a slide 12 which is moved vertically against the action of a spring 8 by a rotary cam 7 on a slide 20 adjusted vertically by a nut and screw 31. The cam-shaft 21 and the wheel shaft 11 are respectively driven by bevel gears 23, 22 and 15, 14, the gears 22, 14 being keyed on a crank-driven shaft 13 and being pressed into engagement with the pinions 23, 15 by a spring 26 which is weaker than the spring 8. The cam, which may have a flat portion 37 connected to a circular portion 36 by curves 38 of small radius so as to produce a quick depression and rise of the wheel block, may be mounted so that the centre of the curve 36 is either on the axis 39, or, as shown, is placed at 40 in which latter case the wheel is depressed slightly during the bending of the first half of the ring and is slightly raised during bending of the other half. The ring is first placed-on the rollers so that the wheel 6 first contacts with it nearer one end and as the wheel rotates it is lowered by the cam to engage the ring as shown in Fig. 3, and then to increase the radius of curvature of the arc and rotate the ring whereby the circumferential length of the ring is progressively brought between the two points of support and the radius of curvature increased. The wheel should leave the ring about the same distance from the other end of the ring as its point of initial contact with the ring was from the first end, as shown in Fig. 6. The movement of the slide 12 may cease during action on the medial portion of the ring or downward movement may be continuous during operation on the first half of the ring and upward movement during the second half. The wheel 6 may be concentric, as shown, or alternatively of eccentric or cam contour and different cam or eccentric wheels may be interchangeably used. Also, if desired, the wheel may be dispensed with, the rotary cam engaging the ring directly. The rings may be concentric or eccentric and in the latter case the cam may be contoured to compensate for the variation in thickness of the eccentric ring to keep the rate of flattening constant. The ring may be made of material such as phosphor bronze, mild steel, brass, so that although the ring remains expanded it recovers to some extent when released from the pressure zone. It is, however, then elastically circumferentially contractible into circular form for positioning in a cylinder or bearing so as to maintain continuous circumferential contact therewith to prevent leakage of oil. The cut ends of the rings may be radial, oblique, stepped; and may be milled at each side and on the inner periphery to a taper to create a wedging action to force the ends apart by the oil pressure when the shaft rotates.