GB1231177A - - Google Patents

Abstract

1,231,177. Making pulleys; cupping. TURNER BROTHERS (BIRMINGHAM) Ltd. 3 July, 1968 [14 July, 1967], No. 32504/67. Headings B3A and B3Q. [Also in Division F2] A pulley having a V-groove defined by two flanks of which at least one is formed of two layers is made by forming from a sheet blank a first cylindrical wall which is reverse drawn to form a second cylindrical wall so that one wall surrounds the other and pressing the two walls to form the two layers of the double thickness flank of the pulley. In one embodiment, a sheet metal blank is initially formed into a cup by a stationary male die (72) (Fig. 2, not shown) and a movable female die (84), the formed blank being ejected by a stripper plate (74) spring urged into an upper position. The blank is further drawn to form a blank 94, Fig. 5, having an outwardly extending flange 92. The blank 94 is placed on a male die 115 and an upper die 102 lowered to cause the flange 92 to be bent upwardly by engagement with a setting face 112 of an annular die 108. Subsequently, the flange 92 is clamped between the face 112 and die 102, the male die 115 is forced down against the action of a spring and the blank 94 is reverse drawn to form a second cylindrical wall 132, Fig. 6. Thereafter, the blank is inserted into a bore 152, Fig. 7, of a stationary die 150 and an upper die 136 moved downwardly, two semicircular sizing dies 160 being cammed inwardly as it does so. When the upper die 136 is retracted, the blank is ejected by ejector pads 142, 156. The pulley is finally formed in a similar apparatus to that of Fig. 7 wherein the two layers 64 and 66 of one flank are brought together and inclined correctly relative to the single thickness flank 68. In another embodiment, a drawn blank, Fig. 10, is placed on a die 172 and reverse drawn by moving down a die sleeve 184 to form a first cylindrical wall (170) (Fig. 11, not shown) surrounded by a second cylindrical wall (198), the flange 92 being clamped between a clamping ring 190 and the die 172. The blank is finished as previously described to form an outermost single thickness flank and an innermost double thickness flank (Fig. 11c, not shown). A blank may be reverse drawn to such an extent that a pulley with a disc-like body instead of a cup-shaped body is finally formed (Figs. 12, 12a, not shown). In a further embodiment, the reverse drawing step is carried out by positioning a blank over a die sleeve 206, Fig. 13, and moving down a clamping plate 218 whereupon a plunger 216 is moved down through the die sleeve 206.