| 摘要 |
1,208,160. Strip feeds. PRODUCTION MACHINERY CORP. 7 -May, 1968 [8 May, 1967], No. 3962/70. Divided out of 1,208,159. Heading B3W. A device for intermittently feeding strip material particularly to a punch press, comprises two spaced feed members, such as rollers, frictionally engaging opposite faces of the strip, drive means for the feed members comprising a driven first rotatable element, such as a pinion, means for driving the first element successively in opposite directions a selected distance, a second element drivingly connected to the feed members, a forward drive train, a reverse drive train and means for selectively interposing the forward and reverse drive trains between the first and second elements in accordance with the direction of movement of the first element whereby the second element repeatedly moves in the same direction. The selective drive unit 20, Fig. 7, for transmitting movement of the pinion 270 to the second element i.e. intermediate shaft 376 and thus to the input shaft (100) of the feed rollers 22, 24, Fig. 2. The unit 20 includes a shaft 344 rotatable by the pinion and journalled in quills 346, 348 themselves journalled in frame members 340, 342. Selectively-energizable clutches 360, 362 one on each end of the shaft 344 connect the shaft 344 alternately to quill 346 and 348. The quills 346, 348 are connected to the intermediate shaft 376 by a forward drive train 372 and a reverse drive train 374 respectively. As rack 260 moves in one direction clutch 360 is energized to drive shaft 376 in the feed direction. As rack 260 is moved in the opposite direction clutch 262 is energized and the shaft 376 is, through the reverse drive train, again driven in the feed direction. Further adjustment of the feed stroke is provided for by having alternative drive trains 400 and 402 for longer and shorter strokes respectively between the shaft 376 and the output shaft 404 which is coupled to the feed roller input shaft (100) at 130 (Fig. 2). As shown, Fig. 2, feed rollers 22, 24 are rotated by an input shaft (100) which through gearing also rotates leveller rollers (26), Fig. 10 (not shown). Each feed roller includes a brake 60 or 62 and jacks 54, 56 are used to adjust the positions of the other parts of the feed device dependent on the nip of the feed rollers. Between each feed stroke hydraulic cylinders 50 are actuated to raise roller 22 and free the strip for accurate location at e.g. punch dies. The lever system, Fig. 5, is actuated to move a rack 260 by rotation of a barrel cam 180 which includes a substantially elliptical cam groove 182 extending between points a and b spaced axially of the cam by a distance which determines the amount of movement of a cam follower 190, Fig. 4. Points a and b are circumferentially spaced from each other by 180 degrees. A cam drive shaft 150 is driven by means of a continuously driven flywheel 140, Fig. 2, when an electrically-energized clutch 158 is engaged. The clutch remains energized until cam 180 has rotated 180 degrees and runs moved cam follower 190 by the axial distance between points a and b. At this time the clutch is released and a brake 160 is energized. On the next rotation of the shaft 150 the cam follower moves axially the same distance but in the reverse distance. A bracket 234 transmits motion from the cam follower to the lever system 16. The lever system comprises a fixed pivot 232, a pair of parallel levers 210 pivoted at 243 to a second pair of parallel levers 240 and a movable pivot 248 about which the rack 260 pivots. The effective length of the lever arm which determines the feed stroke is adjustable by means of a lead screw 282 threadedly received in a trunnion 244 comprising the movable pivot and carrying a nut 286 at its upper end. The nut is rotated through gears 294, 296, 298 by a motor 300 to vary the length of the lever arm by moving the movable pivot through an arcuate path, the gearing also driving a Selsyn indicator 304 which shows the lever arm length and thus the adjusted feed stroke. The lengths of the levers comprising the lever arm are selected to achieve an optimum path for the movable pivot, so that e.g. the rack is prevented from rotating around the pinion 270, throughout the range of adjustment of the lever arm length. |
