Abstract: A method of rolling a ring from a metal blank comprises mounting the blank (2) on a mandrel (4) between two forming rolls (6) located on opposite sides of the mandrel axis. A pair of lower growth control rolls (12) are located below and with their axes parallel to and on opposite sides of the mandrel axis (8), and a pair of upper growth control rolls (16) are arranged above and with their axes parallel and on opposite sides of the mandrel axis (8). The spacing between the pair of upper growth control rolls is different from that between the pair of lower growth control rolls. As the ring is rolled, both the forming rolls and the growth control rolls are engaged with it. In a modification of the method, the upper growth control rolls are replaced by a single roll (20) with its axis disposed directly over the mandrel axis.

Abstract: A method is disclosed for the manufacture of gear wheels having two axially adjacent gears (4,6) thereon. A blank is prepared with the two gears crudely formed thereon by compressing and sintering a shaped mass of substantially metal powder. The blank is then mounted for rotation about a first axis, and the gears are roll-formed on the blank by rotating the blank in meshing engagement with respective dies (10,12) mounted for rotation about second and third axes substantially parallel to the first axis.

Abstract: A gear wheel is formed from a pressed and sintered powder metal blank in which the metal powder comprises an admixture of iron powder and at least one alloying addition and the gear wheel is surface hardened by applying densifying pressure only to the tooth root regions or only to the tooth flank regions in order to establish densification in the range of 90 to 100 per cent of full theoretical density to a depth of at least 380 and up to about 1,000 microns.

Abstract: An annular workpiece 6 is rolled between two oppositely disposed forming rolls 2, 4, and two oppositely disposed growth rolls 22 and 24 acting at right angles to the line of action of the forming rolls. The forming rolls 2, 4, are brought together to roll form the workpiece 6 to a wall thickness dependent upon its weight, and the advance of the growth control rolls 22, 24 is controlled to a position which is also dependent upon the weight of the workpiece 6.

Abstract: Rings are made from tube stock (10) or bar stock by cold rolling successive end portions (78) of the latter between profile rolling elements (42, 44) of a plurality of rollers which also include parting tool elements (40) for making a parting groove, also by cold rolling. The parting groove is formed, by the parting tool elements while the profile rolling operation takes place during the latter part of the parting groove forming operation. With bar stock, a bore is made through the end portion of the stock, e.g. after the parting groove is formed, the latter having a depth just insufficient for final parting-off, which takes place during subsequent machining of the bore of the ring. A locating groove (76, 80) is also formed, by means of a grooving tool (74), simultaneously with the rolling operation.

Abstract: 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.

Abstract: 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.

Abstract: A method and machine for preparing an annular workpiece from tube stock, using a part-off rolling tool. The rolling tool is advanced radially of the tube stock to a depth approximately equal to the desired bore diameter of the workpiece so as to partially sever a length from the tube stock. The inside of the length is then machined to the desired bore diameter. The machining either causes the length to be fully severed from the rest of the tube stock or leaves it connected thereto by a thin annular band. In the latter case the rolling tool is then advanced further to fully sever the length from the rest of the tube stock.

Abstract: A method of rolling an initially annular workpiece between forming rolls in which after the forming rolls have been fully advanced they are retracted initially slowly for a predetermined distance. The forming rolls can then be further retracted at a greater speed. The slow retraction reduces the out of roundness of the finished rolled ring.

Abstract: A rolling machine for rolling an annular workpiece. The machine includes a mandrel for supporting the workpiece. The mandrel has two co-operating sections separated across its axis and a part of each section is shaped to conform to the rolled profile of a part of the workpiece.

Abstract: A method of roll forming an annular workpiece to a desired shape from a workpiece having dimensions within a tolerance range, in which the difference in weight between the workpiece and a nominally sized workpiece is determined and the workpiece is then roll formed to its desired shape by being squeezed between at least two rotating forming members which advance relatively towards one another to a fully advanced position to impress the desired shape into the workpiece followed by maintaining the forming members at their fully advanced position to complete the roll forming for a period of time known as the dwell time.

Abstract: A method of forming to shape an initially annular workpiece in which the workpiece is rotated and squeezed between a pair of opposed forming rolls at least one of which is advanced relatively towards another. A pair of opposed growth control rolls are situated at right angles to the forming rolls, contacting the outer surface of the workpiece during at least a part of the rolling by the forming rolls. When the forming rolls have advanced to a predetermined depth of roll the force exerted by the growth control rolls on the outer surface of the workpiece is increased and the rolls continue to move towards one another until an adjustable dead stop is reached.