Formflo Limited

Peter J Holt

Ronald C Andriessen

A ring rolling machine for cold rolling bearing cages and the like has a working station (32) at which the rolling operation is performed on an annular blank by an annular die (80,82) co-operating with a mandrel (50). The die is held coaxially in a die housing (74) mounted rotatably in one of two through openings (62,64) in a shuttle (42) which is reciprocated between the working station and two alternate transfer stations (28,30) at which the front die insert (82) is ejected with the rolled ring and re-inserted with a fresh blank. The die housing projects through a slot (70) in the shuttle to engage the die drive roll (78), and via the die transmits rotation derived from the drive roll to the mandrel and a pair of mandrel support rolls (110) which apply radial force to the mandrel. The mandrel support rolls are mounted in a head on a shaft pre-tensioned to control their axial position without fasteners; they also control the axial positions of the die and mandrel.

Ring rolling

The invention relates to methods and apparatus for making rings from tube stock (10) by a part-off rolling tool (12,15) which is advanced radially into the tube stock to form successive rings, e.g. annular blanks for subsequent roll forming into bearing rings. The tube stock is indexed forward after separation of each ring. Errors in the length of tube stock indexed forward each time are contained by forming a locating groove (47) on the tube stock by means of a groove-rolling tool (40) set at an appropriate axial distance from the part-off rolling tool (12) and moved radially with it. In the next cycle the groove (47) automatically centers the part-off tool as the latter begins its advance into the tube stock, so as to give the correct axial length of the finished ring. The part-off tool is stopped before fully penetrating the tube wall, which is then machined. Final separation takes place during this machining or in a subsequent finishing pass by the part-off tool.

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Cheltenham, United Kingdom

Peter J Holt