Patent GB-936753-A (GB)
Title: Improvements in or relating to a press
IPC: B21D22/06
Filed: 1961-03-06
Abstract: 936,753. Cupping; punching; blanks transferring. HAMILTON COSCO Inc. March 6, 1961 [June 2, 1960], No. 8098/61. Class 83 (4). A metal working press comprises a plurality of longitudinally spaced pairs of mating dies supported on a slide carried from an elongated supporting frame, means on the frame for moving a first die in each pair of the dies vertically into engagement with the second die in each pair of dies to perform work steps on a plurality of workpieces interposed therebetween, each of the second dies being arranged releasably to hold a workpiece thereon, and means for simultaneously moving each of the second dies longitudinally with respect to its mating die for moving the workpieces from one pair of dies to another and finally ejecting the workpiece from the press. In an embodiment the press has four stations; a pick-up station, a drawing station, a piercing station and a discharge station. The two die assemblies are supported above the press bed 16 and the two lower dies are carried on platens 29 and 30, each vertically reciprocable independently of the other by hydraulic cylinders 32 and 33 respectively. A conventional hydraulic system is mounted on the cover-plate 18 of the press. To move the workpieces through the press a slide 50 is slidably and adjustably mounted on the underside of a top press plate 20. The slide is actuated by an hydraulic cylinder 54, the ram of which is attached to a slidable gear rack 60, Figs. 7 and 8, which meshes with a pinion 62 mounted on the top plate 20. The pinion is connected to a link arm 68, the outward end of which is connected to one end of a pair of links 72, the other end of the pair being attached to the slide 50 adjacent its discharge end. A pair of stop blocks 80 limit the movement of the slide. A workpiece holder is mounted on the lower face of the slide 50 and projects outwardly beyond the end of the slide and comprises a pair of spaced brackets 85, provided with permanent magnets 94 for holding a workpiece on the brackets between positioning fingers 92. The workpieces 96 are stacked on a platform 98 between guide posts 100 and a magnet 104 is mounted on the platform to separate the workpieces and facilitate their removal. The workpieces are picked up and deposited on the brackets by a suction cup 112 carried by the ram of an hydraulic cylinder 106, Figs. 5 and 6. An oil film is sprayed on to each workpiece from an atomizing gun 113 as it is being raised from the stack. A spring- loaded knock-out plate 114 is provided for removing the workpiece from the brackets 85 said plate being actuated by an hydraulic cylinder 122 mounted on the lower face of the cover-plate 18. A pair of stripping arms 126 having extending fingers 130, 132 ensure that the brackets only carry one workpiece at a time. The fingers are vertically swingable to enable them to receive and pass the edges of a slightly bent workpiece. A pair of die assemblies 140 and 142 are mounted on the lower face of the slide 50 to overlie the platens 29 and 30. Each die is adapted to hold a workpiece 96 so that the dies and the brackets 85 constitute a plurality of workpiece holders for moving the workpieces through the press upon movement of the slide 50. The die 140 comprises a drawing die 146 and a spring-loaded knockout plate 150, Fig. 3. The die 146 co-operating with a punch 174 mounted on the platen 29. An hydraulically operated draw ring 172 surrounds the punch. The upper and lower die assemblies are slidably interconnected by a pair of guide posts 176 which disengage the upper die when the platen is in its lowered position to enable the upper die to move longitudinally with the slide. A plurality of locator buttons 178 on the draw ring 172 position the workpiece on the punch 174 when ejected from the brackets 85 on the slide. After the drawing operation the workpiece is retained on the drawing die 146 so that the die acts as a work holder to transfer the workpiece to the next work station, i.e. the piercing dies, on movement of the slide, whereupon a new workpiece is delivered to and ejected on to the lower drawing die. When the drawing die 146 is disposed over the platen 30, a knockout plate 150 ejects the workpiece on to the piercing die 198 carried on the platen, after which the slide returns to its initial position. The upper piercing die assembly comprises a punch pad 204 carrying a plurality of punches 208 extending through a vertically movable spring-loaded stripper plate 212. The punch pad also supports a spring-loaded knockout rod 218. As the piercing die 198 is moved upwards by the cylinder 33 the punches 208 pierce the workpiece and the waste metal falls through openings 200 and knockout slots 202. After the piercing operation the workpiece is retained against the stripper plate 212 by magnets 226 mounted thereon. The next movement of the slide carries the upper piercing die outwardly beyond the extent of the press bed 16 and under an hydraulic ram 230 which engages the knockout rod 218 and ejects the finished workpiece on to a conveyer 232.