Patent GB-954483-A (GB)
Title: Improvements in or relating to stamping or embossing machines
IPC: C14B1/56
Filed: 1959-07-09
Abstract: 954,483. Marking machines; feeding foil. BRITISH UNITED SHOE MACHINERY CO. Ltd., and R. O. C. GADD. July 4, 1960 [July 9, 1959], No. 23574/59. Headings B6C, B6F and B6J. [Also in Division F2] A stamping or embossing machine for marking leather or other non-metallic sheet material comprises a pneumatic piston-and-cylinder to move a marking device to and from a position where it applies pressure to a workpiece, a solenoid-operated valve in the air pressure circuit, electrical timing means to automatically control a machine cycle, and switch means to initiate operation of the timing means and an operative machine cycle by controlling the valve to move the marking means to pressure position, the timing means reversing the valve to retract the marking means after a predetermined but adjustable time period. As shown, a blocking machine for marking shoe parts has a stamping head 8 secured by bolts 28 to a plate 24 mounted on the lower end of a piston-rod 16. The bolts 28 are slidable in holes in the plate 24 and when the head 8 is in its raised position a small airspace separates it from the plate 24 so as to minimize heat losses from the head, which is heated by an element 27. The heating of the head is controlled by the setting of a temperature control dial 167. The piston-rod 16 is carried by a double-acting piston mounted in a pneumatic cylinder 22. Air under pressure is introduced into the cylinder above or below the piston to lower or raise the stamping head into or out of contact with a workpiece resting on a table 4. The table 4 has a relatively hard rubber insert 6 upon which the workpieces are placed and which can be turned round or turned over in the table to compensate for wear. An adjustable back gauge 10 on the table serves as an abutment for the rear edge of a workpiece. A strip of blocking foil 90 is interposed between the stamping head and a workpiece on the table 4. A guard 168 of transparent material is pivotally mounted at its upper edge in front of the stamping head and is connected by means of a rod 174 to an on-off valve 178 in the pneumatic circuit which effects reciprocation of the stamping head. When the guard is in its raised position the valve 178 is closed and the stamping head cannot be actuated. The valve is opened when the guard is lowered to the postion shown. Further guard plates 192 are pivotally mounted on the machine frame 2 at 193 and are spring-biased to the horizontal position shown. When the stamping head descends to make an impression the foil 90 is pressed against the guard plates 192 and swings them downwards. The pneumatic circuit of the machine has two solenoid-operated valves which control flow of air under pressure to the top and bottom ends of the cylinder 22. An impression cycle of the machine is initiated when the operator depresses a treadle connected by a Bowden cable 198 to a pivoted arm 200; as the arm 200 pivots a cam 202 secured thereto actuates a microswitch 204 in the electrical control circuit of the machine, which circuit includes a timing device, set by means of a dial 166, for regulating the duration of the dwell of the stamping head. The pressure of air in the pneumatic circuit can be regulated by a hand control 182. Embossing surfaces.-A carrier 30 for loose type 32, Fig. 1, is fixed on a shaft 54 rotatably mounted in the stamping head 8. One end of the shaft has a hand lever 42 mounted thereon whereby the shaft can be rotated and the carrier 30 moved between a downward facing, operative position and a foreward and upward facing position. In the latter position the type 32, which are held in channels 34, Fig. 3, by spring-biased plungers 36 can be readily exchanged. A member 72 is detachably carried on the stamping head 8 and forms a bearing for concentric shafts 76, 80, 82 on which are mounted type wheels 66, 68, 70 respectively. The concentric shafts also carry hand wheels 66<SP>1</SP>, 681, 701 for setting the type wheels. Feeding foil.-The foil 90 is fed step-by-step from a spool 92, round guide pegs 106, 108 and beteeen a rubber surfaced feed roller 104 and another rubber surfaced roller 110. The roller 104 is mounted on a spindle 120 journalled in a bearing 121 and having secured thereto a ratchet-wheel 124. A shaft 134 is aligned with the spindle 120 and is journalled in a bearing 136. One end of the shaft 134 carries an arm 130, Figs. 5, 6, on which are pivoted two pawls 125, 126. The other end of the shaft 134 extends into an air cylinder 138 and carries a paddle 140. A stop member 141 is also housed in the cylinder 138. Air under pressure is admitted to the cylinder alternately through ports 137, 139 so as to cause oscillation of the paddle 140 and shaft 134. When the shaftrotates anticlockwise, Fig. 6, one or other of the pawls 125, 126 engages the ratchet-wheel 124 so that the spindle 120 and roller 104 are rotated. When the shaft 134 rotates clockwise the pawls 125, 126 move idly over the wheel 124 which is restrained against clockwise rotation by one or other of two pawls 158 pivoted to the bearing 136. The pawls 125, 126 can be lifted out of engagement with the wheel 124 before completion of the anticlockwise movement of the shaft 134 by adjustable cam means (not shown) set by a dial 148, Fig. 5, whereby the amount of foil fed in any one step may be regulated. The foil 90 is moved during the upstroke of the stamping head, the flow of air under pressure to the port 137 being controlled by a valve 210, Fig. 2. This valve is opened by a bell-crank lever 208 when the latter is pivoted by the engagement therewith of a stop 206 carried by the stamping head. The stop 206 is vertically adjustable so that it does not contact the bell-crank lever until the type carried by the head 8 are clear of the foil 90.