Patent GB-952055-A (GB)
Title: Improvements in or relating to platen presses
IPC: B41F1/08
Filed: 1959-06-23
Abstract: 952,055. Blocking machines; feeding foil. J. H. ELLIS. June 17, 1960 [June 23, 1959], No. 21545/59. Headings B6F and B6J. [Also in Division F2] A blocking press comprises a platen 31 disposed above a station at which a workpiece 57 can be located, an axially slidable vertical shaft 29 on the lower end of which the platen is mounted, a piston 45 carried on the upper end of the shaft and slidable in a cylinder 43, the height of the cylinder above the station being adjustable, and means for supplying and controlling the supply of gaseous fluid, e.g. air, under pressure to the cylinder at opposite sides of the piston so as to cause downward movement of the platen to its operative position, dwelling of the platen at that position for a predetermined period of time and raising of the platen to its uppermost position. The cylinder 43 is carried by a bracket 21 and the shaft 29 is slidable in a vertical bore 27 in the bracket. The bracket 21 is slidably mounted on a post 3 secured to a base plate 1 and its position on the post is adjustable by means of a threaded rod 11 which carries a handwheel 19 at its upper end and engages in a threaded bore 25 in the bracket 21. A ribbon 69A of blocking foil is fed between a die 33 detachably carried by the platen 31 and the workpiece 57. The foil feed mechanism is carried by a member 71 secured to the bracket 21 and comprises a supply spool 99, Fig. 3, guides 119, 121 and feed rollers 109, 111, between which the foil passes before being fed to waste. The roller 109 is driven by a chain and sprocket connection 95, 91, 107 from a shaft 75 to which a pinion 77 is secured. The shaft 75 is rotated by a rack 79 of which the teeth engage the pinion 77 and the upper end of which is slidably engaged in an arm 81 secured to the shaft 29. Abutments 85, 89 are threaded on to the upper end of the rack 79 and a spring 83 biases the abutment 89 into contact with the arm 81. The rack passes through an aperture in the bracket 21. The rack is moved downwards when the platen moves downwards to engage the workpiece until it strikes an adjustable abutment 87 carried by the member 71 after which further downward movement of the platen causes compression of the spring 83. During the first part of the upward movement of the platen, the rack remains lowered; it is not raised until spring 83 has been relaxed and arm 81 engages abutment 89 to lift the rack. The rack then moves upwards with the platen. Rotation of the roller 109 takes place only on the upward stroke of the rack there being a free-wheel connection between the sprocket 91 and the shaft 75. The workpiece 57 is carried on a turntable 53 together with other workpieces; the turntable is automatically turned through a part of a revolution between strokes of the platen by means of a pneumatically operated rack and pinion device having a free wheel connection with the turntable shaft 55. A protective screen 127 is hinged to the bracket 21 and controls a microswitch which prevents operation of the press unless the screen is in the closed position shown. A timing device is incorporated in the control circuit of the machine to regulate the dwell of the platen in operative position.