GB839148A - Movable bolster for a metal working press - Google Patents

Abstract

839,148. Metal-working presses. U. S. INDUSTRIES Inc. Jan. 30, 1958 [Jan. 10, 1957], No. 3101/58. Class 83 (4). A mechanism for easily and quickly replacing die sets in a metal working press having a bed 11, a crown 12, uprights 13, between the bed and crown, and a slide 14 vertically movable between the uprights comprises tracks on said bed arranged between opposed uprights and extending outwardly from the press, a bolster having wheels for movably supporting the bolster on said tracks said bolster being adapted to receive a die set thereon outside of the press, wherein coacting parts are provided on the bolster and the press for accurately locating the bolster at a predetermined position on the press bed so that after the upper die is attached to the slide the dies will match during the pressing operation, and means for lowering the bolster to the press bed prior to the press operation giving the bolster a firm foundation. In an embodiment a double moving bolster assembly 15 is reciprocable between the uprights. Mounted in the press bed are a pair of pneumatic die cushions 16 supporting a pressure pad 20 controlling a draw ring 30. The pressure pad is retracted when making a die change by an auxiliary pull-down cylinder 23. A die shoe 27 secured to the top of the bolster by T-bolts located in T-slots 39 carries a lower die 28. An upper die 29 is secured to the slide 14 by hydraulically-operated die clamps 31. The double bolster assembly includes bolsters 34 and 35 pivotally connected by couplings 36. Both bolsters are mounted on wheels 45 which run along tracks 46 and 47. Additionally supporting the bolsters in the press are four wheels 48 mounted on hydraulic cylinders 49. At the inner end of the tracks 46 and 47, wheel recesses 53 and 54 receive the bolster wheels to allow lowering of the bolsters on to the press bed when the cylinders 49 are operated to lower the support wheels 48. The outer ends of the bolsters are similarly lowered by hydraulically-operated track sections 55 and 56. Stops on the bolster coacting with adjustable abutments 62 mounted on the press bed and a pair of plugs on the bed engaging in recesses in the bolster, accurately locate the bolster on the press. A reversible hydraulic motor 67 drives the bolsters back and forth through rack- and-pinion gearing 74, 75. Before operation of the press, the bolster within the press is clamped to the bed by a pair of T-shaped bars 76 connected to a plurality of pneumatic cylinders 79 mounted in the press bed. Electric and hydraulic circuits (not shown) control the press and bolster operation. In a modification, single bolsters 80 each provided with four wheels are used and these single bolsters are removed and delivered to the press by an overhead crane 81. Vertically movable track sections are provided, one for each wheel, for lowering the bolster on to the press bed.