Patent GB-426816-A (GB)
Title: Improvements in or relating to wire stitching machines
IPC: B27F7/21
Filed: 1933-11-03
Abstract: 426,816. Stapling. POLLAK, J. E., 20, Holborn, London.-(Brehmer, Geb. ; Plagwitz, Leipsic, Germany) Nov. 3, 1933, No. 30614. [Class 89 (iii)] In a stapling or wire-stitching machine, having a work carrier arranged to be displaced independently of the machine drive to present the work to the stapling head, the stapling mechanism is run continuously, and control of the stapling is effected by interruption of the wire feed as required. Means preferably is provided whereby staples can be inserted singly or in uninterrupted sequence. The stapling head 12 is carried by a column 11 and is driven continuously by a shaft 17. Wire from a reel 13 is fed by rolls 15, 16 formed with inter-engaging combs 15<a>, 16<a>, Fig. 4, designed to feed a staple length at each rotation of the rolls. The shaft 31 of the roll 15 is slidably mounted and the roll 15 is normally held out of alignment with the roll 16 by a spring 33, so that no wire is fed. A lever 36 for bringing the rolls into alignment carries the armature 35 of an electromagnet 34 which is in circuit with a source of electric supply and a switch device E. A work-supporting arm B is pivoted to the column 11 at 21, and normally is held in lowered position by a spring 22. In operation, work to be stapled is placed on the arm B, and the latter is raised by a treadle 25 and pitman 24 acting through a cam lever 20 and roll 18. The latter is replaceable for different thicknesses of work. Further depression of the treadle closes the switch E through a tappet 40, so that the electromagnet 34 is energized and a staple length of wire is fed. In order to ensure that the electromagnet 34 shall not be energized at a time when the combs of the rolls 15, 16 are in feeding engagement, a timing switch C, operated by a cam 43 on the shaft 17, is inserted in the electromagnet circuit. Contacts 37, 38 are closed, when the armature 35 is attracted, in order to short-circuit the timing switch. The combs of the rolls are grooved to engage the wire, whereby the rolls cannot be disaligned before the completion of a wire-feeding operation. By this arrangement, staples will be formed and driven so long as the treadle is held depressed. The anvil arm B, which may take various forms, embodies clinching mechanism actuated by a rod 29, lever 28, and cam on the shaft 17. In order to prevent lowering of the arm B before the last staple driven has been clinched, a catch device 46 may be provided on the treadle arm 25a, which allows the treadle to rise sufficiently to open the switch E, but requires a definite release movement to allow the arm B to descend. Alternatively, the arm B may be locked in stapling position by an electromagnetic lock energized under control of the timing switch C, or of a second tappet on the pitman 24. In order that the operator may insert a single staple, or a sequence of staples, at will, a switch E of the form shown in Fig. 13 and a control circuit as shown in Fig. 15 are provided. The switch comprises three sets of contacts 75, 76, 76<a> adapted to be bridged by arms 77, 78, 78<a>, the arm 78<a> being displaced relatively angularly on the common rock shaft 79. The latter is rocked by an arm 80 co-operative with the tappet 40 and with a spring 81, the arrangement being such that depression of the treadle first acts to bridge the contacts 75, 76, and later to bridge the contacts 76<a>. The contacts 76, 76<a> are connected to the positive end of the electric supply, Fig. 15, and the contacts 75 to the negative. When the treadle is depressed to close the contacts 75, 76, the wire feed electromagnet 34 is energized through the timing switch C and contacts normally bridged by the armature 56 of an electromagnet 58. As a consequence, the armature 35 is attracted to feed a staple length, and contacts 57, 57<a> are closed to energize the electromagnet 58. The armature 56 is then attracted, and breaks the circuit of the electromagnet 34, so that another staple length cannot be fed until the switch E is opened and again closed. Multi-stitching is obtained at will be short-circuiting the electromagnet 58 by means of a separate switch 63 or by the contacts 76<a> of the switch E. In a modification of this arrangement, a second timing switch operated from the shaft 17 is inserted in the circuit of the electromagnet 58, and acts to prevent energization of the latter before a complete staple length of wire has been fed, and contacts in circuit with the contacts 76<a> act to short-circuit the timing switch C during multi-stitching.