GB876309A - Improvements in or relating to stapling machines - Google Patents

Abstract

876,309. Reciprocating motors. ELASTIC A.G. Nov. 4, 1957 [Nov. 3, 1956], No. 34375/57. Class 35. [Also in Groups VII and XXXVII] An electrically operated stapling, nailing, &c., machine includes an electromagnet coil 2 with an armature 1 axially movable therein adapted to impart hammer blows to a ram 11 mounted separately from the coil 2 between the coil 2 and a guide 26 on which the staple &c. is supported, whereby the ram 11 can transmit successive hammer blows from the armature 1 to the staple &c. S. In an embodiment intended for direct-current operation, in order that the coil 2, Fig. 1, may be energized during the whole of each working stroke of the armature 1 and may be disconnected from the power supply at the end of such stroke, the coil 2 is energized over a pair of contacts carried by a self-holding relay the coil 3 of which is controlled in turn by contacts 5, 6 carried by the ram 11 and operated by the armature 1. The contacts 5, 6 are opened at the lower end of the stroke of the armature 1 to disconnect the coil 3 which remains disconnected until the armature returns to its upper position to close contacts 4, 4a over which the relay coil is re-energized. The operation repeats automatically until a main switch, operated by a vertically displaceable abutment 23, is opened by removing the machine from the workpiece. The movable contacts of the relay over which the coil 2 is energized are carried by a disc 30 connected to the relay armature 30b by inclined spokes 37 radiating from a rotatable hub. When the armature 1 is operating it forces air from the chamber C against the spokes 37 which act as propeller blades causing the disc 30 to rotate whereby the relative positions of the fixed and movable contacts of the relay are modified so preventing localized wear of these contacts. The armature 1 is returned to its raised position by a spring 12 between the armature 1 and ram 11. After a stapling operation the ram 11 is returned to its raised position by a leaf spring 13, or by an electromagnet, which is rendered inoperative during the stapling operation by a lever 24 actuated by an abutment 22 which is vertically displaced when the machine is held against the workpiece. In a modification intended for alternating- current operation, the frame F, Fig. 3, of the machine is formed in two sections 38, 39 pivoted together at 40 and urged apart by a spring 41. The coil 2 is carried by the section 38 whilst the ram 11 is carried by the section 39 so that as the staple &c. is driven, the operator can control the relative spacing of the coil and ram.