Patent GB-710627-A (GB)
Title: Improvements in or relating to sheet perforating apparatus
Inventor: BROIDO DANIEL
IPC: B26F1/00
Filed: 1952-10-01
Abstract: 710,627. Perforating sheet material. BRITISH TABULATING MACHINE CO., Ltd. Oct. 1, 1952, No. 24588/52. Classes 31 (1) and 31 (2) Apparatus for perforating a sheet or sheets of paper or like material the thickness of which is equal to or greater than the minimum dimension of a perforation comprises means for forcing a piercing member through the sheet or sheets which produces a burred hole therein, and subsequently operable means for heating the piercing member sufficiently to burn away the burr surrounding the hole. In the form shown, a group of needles 1, which produce perforations according to a predetermined code, are carried by a block 2 fixed to the lower end of a slidable shaft 16 which is operated by the handle 21, Fig. 1, of a pivotally-mounted lever 20 provided with a cam-shaped portion 25 which engages a roller 26 mounted on a pivotally-mounted lever 27 which carries a pin 29 engaging a slot in the lower end of a slidable shaft 30. Attached to the upper end of the shaft 30 are a series of blocks 5, 7, 8, 9, and 10, Fig. 3, on which a pad 4 of sheets is placed so that as the shaft 30 is raised the pad is clamped between the block 5 and a fixed plate 3. The lever 20 has a slot 22, Fig. 1, which engages a pin 23 fixed to the shaft 16 so that the handle 21 can make a limited downward movement before the shaft 16 is moved thus ensuring that the pad 4 is clamped before the needles descend. As the handle 21 is moved further downwards, the shaft 16 is moved to force the needles through the pad. Just before the handle 21 has completed its downward stroke, the lower edge of the lever 20 strikes one end of a pivotally-mounted lever 33, Fig. 2, the other end of which carries a pin . 36 engaging a slot in a lug 37 in a contact slide 11 so that the latter is moved to the right. The slide consists of two end portions joined by three strips 32, Fig. 4, which lie between the blocks 5 and 10 and are alternately arranged with the blocks 7, 8, and 9. Each of the strips 32 has wedge-shaped portions 12 so that when the slide is shifted by the lever 33 each of the needles is clamped against a notch in one of the blocks 7, 8, or 9. The block 2 is connected to one terminal of the secondary of a step-down transformer 44, Fig. 6, the other terminal of which is connected to the blocks 7, 8, and 9. The primary of the transformer is connected to main supply lines 47 through an interval timer 46 The slide 11 has attached thereto an insulating member 40, Fig. 4, extensions of which engage two sets of contacts 42, 43 mounted on an insulating block 41. On movement of the slide, the contacts 42 are opened and the contacts 43 closed. An indicator lamp 45 is connected across the transformer secondary to warn the operator not to release the handle 21 until the lamp is extinguished by the timer switching off the transformer. As a further precaution, the contacts 42 are included in the reset circuit of the timer so that when the handle 21 is released, the contacts 42 will close to reset the timer to "off" if it has not already reset automatically. Alternatively, a solenoid may be connected across the transformed secondary and used to operate an interposer which locks the lever 20 against movement so long as the solenoid is energized. The block 2 may be made detachable so that a similar block having a different arrangement of needles may be substituted; alternatively, the block may be replaced by a head carrying a complete group of twenty-five needles which can be selectively locked in an operative position by means of slides. Each slide is inserted in a cavity in the head above the needles and has holes punched in it in positions corresponding to the needles not required for punching.