Patent GB-1356611-A (GB)
Title: Manufacture of spacerexpanders
IPC: B23P15/06
Filed: 1971-05-11
Abstract: 1356611 Making spacer-expanders; angular bending; coiling; pucnhing; shearing SEALED POWER CORP 11 May 1971 [21 May 1970 (3)] 14118/71 Headings B3A B3E and B3W [Also in Division F2]  A method of making a spacer-expander for a piston oil ring assembly of an i.c. engine includes repetitively blanking flat ribbon metal stock 170 to form successive incremental sections, each comprised of two parallel bands 70, 72 defining side margins of the strip, a transverse strut 74 spaced substantially equidistant from adjacent struts and two legs 76, 78 extending substantially parallel to the strut, the legs being connected at one end to each band and having free ends terminating short of the opposite band, bending the legs to their final inclination relative to the bands and bending the struts to form the strip into a channel section configuration. The forming operations are performed at work stations 1-5, 7-9 of a machine 100, Fig. 1, which has a motor 106 driving a flywheel 108 connected via a clutch 112 to a crankshaft 114. Connecting rods 120, 122, 124 operate stations 1-5 and 7 by means of rams 126, 128, 130. The crankshaft also actuates a strip feed mechanism 154 and is fitted with a pick-up 160, which provides an input signal to a suitable counter control. The strip is passed through a lubricating tank 202 upstream of the feed mechanism, which on each working stroke advances the strip by slightly more than the required distance and then pulls it back into registry. Punching and bending the strip (work stations 1-5).-A die assembly 136 at work station 1 punches six equispaced transverse slots (174)- (184), Fig. 2 (not shown) in the strip 170 at each stroke of the ram 126. After twenty strokes the assembly 136 is shifted transversely of the strip feed to punch a pair of slots (188) (190) in a joint area (186) of the strip. At station 2 a die assembly 138 blanks the legs 76, 78 and is shifted transversely after twenty strokes to blank holes 226, Fig. 3. A die assembly 140 at station 3 bends the ends of the legs 76, 78 and after twenty strokes it is shifted to cut away portions of the bands 70, 72 at the holes 226, Fig. 4 (not shown). The strip passes to station 4, Fig. 6, where it slides along a plate 270, which is raised by springs clear of die horns 286 (288), Fig. 11 (not shown). A punch 268 first clamps the bands 70, 72 against the plate 270 and then forces the plate down against the springs to bend the legs 76, 78 against the horns 286 (288). The action of the springs on the plate strips the legs from the horns. A strip guide 222 is provided with a pivoted arm 312 to form an incline between fixed and movable strip guides at stations 3 and 4. Work station 5, Fig. 14, includes six punches A-F having an associated pair of anvils (440) (442), Fig. 17 (not shown), and a further four punches G-J having associated sets of horn dies (454)-(468), Fig. 24 (not shown). Each strut 74 is worked on by alternate punches, i.e. punches A, C, E, G, I or B, D, F, H, J. Punches A-F are identical in shape, but the anvils 440, 442 deepen progressively, so that the struts are bent progressively, Figs. 17, 18, 19 (not shown). The lateral spacing of the horns of the dies (454)-(468) decreases progressively, while their depth remains constant, to bend the strip to the cross-section in Fig. 22, the legs fitting into spaces between the punches as bending progresses. A stripper 472 is biased by springs 474, 476 and has an extension 496 directed toward station 4. The stripper clears the strip from the anvils and moves in unison with and by the same amount as the strip support surface in station 4. A cover 508 located over the extension 496 prevents the strip buckling as it is advanced. A stationary upper stripper and guide structure is provided and has flanges overlying the bands 70, 72 and has fingers 568-574 extending completely over the strip. The fingers are interdigitated with the punches G, H, I, J and clear the strip from them as they move upwardly. The strip then passes through an exit guideway formed by a guide block 580 and cover 582. The trailing end of the stripper 472 moves in a notch 584 in the block and additional guidance is provided by a rib 596, which protrudes between the bands 70, 72. The stress in the strip is relieved in a heater 600 at station 6. Forming the spacer-expanders (station 7).-The strip is fed through an entrance guide block (702) and cover (708), Fig. 30 (not shown), into alignment with an anvil 720 having a curved forming surface 732, Fig. 35. As the ram 130 descends, a roller 784 on a block 792 engages and then pivots an arm 776 anticlockwise. The arm 776 pivots an arm 764 on a rocking shaft 736 to drive a coiling pad 728 against the strip and curl it on the anvil. As the ram rises the pad is pivoted away from the anvil by a spring. The strip is guided onto the surface of a plate 812 as it is coiled. When a complete circle has been formed, a shoe 876 is moved into alignment with a button 858 of a cut-off punch 850. The ram 130 actuates the punch to sever a portion (192), Fig. 4 (not shown) of the strip end joint portion 186, Fig. 3. As the punch 850 rises, the formed ring falls clear of the anvil and is blown by an air tube 902 onto a guide tube 890, Fig. 1. The guide tube is fitted with a fin 900, which separates the ends of the ring as it falls down the tube until it reaches a nose cone 910.  Trimming the ring ends (station 8).-Pushers 946, 948, Fig. 1, engage the ring and move it downwardly onto supporting shelves 1020, 1020<SP>1</SP>, Fig. 42. A die shoe 1070 is advanced up to the ring ends and sockets 1096, 1096<SP>1</SP> in a block 1088 are moved into alignment with shot pins 1098, 1098<SP>1</SP>. The pins are then driven into the sockets, to provide a firm base for the subsequent shearing and bending operations. Fingers 1064, 1064<SP>1</SP> are advanced towards the ring and when their nose portions 1066, 1066<SP>1</SP> engage the ring, they pivot about pins 1054, 1054<SP>1</SP> to embrace the ring, thereby locating its ends relative to the die shoe 1070. A sub-assembly comprising a punch shoe 1144 and a clamp shoe 1146 is advanced towards the shoe 1070. A clamp 1156 holds portions 192a, 192b of the ring ends, Fig. 48, on a die clamp 1110 and clamps 1154, 11541 hold struts 74, 74<SP>1</SP> on horns 1106, 1108. The shoe 1144 drives punches 1150, 1150<SP>1</SP> through the clamps to trim the portions 192a, 192b from end tabs 1275, Fig. 53, which are then bent by the punches and coined into their final position by punch surfaces 1153, 1153<SP>1</SP>. The shot pins 1098, 1098<SP>1</SP> are retracted and then the shelves 1020, 1020<SP>1</SP> and the fingers 1064, 1064<SP>1</SP> opened simultaneously. The pushers 946, 948 are again actuated to push the ring along a tube 926, which expands the ring. The finished spacer-expander rings push preceding rings along the length of the tube. Removing the finished rings (station 9), Fig. I.-A paper tube 1200 is reciprocated by a sufficient amount to locate inside the tube 926 as the lowermost ring is pushed off the tube by the stack of finished rings. The rings are similarly pushed down the tube 1200 and when it is full it is removed manually and replaced by another tube.  Malfunction sensing system, Fig. 1.-Strip guides 216, 218, 220, 222 are provided with yieldably restrained covers, which are arranged to lift should a jam-up occur in any of stations 1-5. As they lift, they contact grounding fingers, e.g. finger 1260 at station 4, thereby actuating magnetic brakes 118 and disengaging the clutch 112 to stop rotation of the crankshaft 114.