Patent GB-707428-A (GB)
Title: Improvements in or relating to metal-shearing machines
IPC: B23D19/02
Filed: 1952-01-03
Abstract: 707,428. Shearing. HORSFALL, H. April 1, 1953, [Jan. 3, 1952], No. 28238/51. Class 83 (4). [Also in Group XXIII] A sheet-metal shearing machine comprises two opposed elongated blades 14, 15, Fig. 3, adapted collectively to support the work 39 with their operative edges in closely-spaced relation, and a flat-edged rotary cutter 37 which has a thickness corresponding to the width of the gap between the blades and projects into such gap so that the work is severed upon relative linear motion between the blades and cutter, the cutter being so mounted as to be capable of ready replacement by an abrasive wheel whereby either of the blades may be re-sharpened in situ. The blades 14, 15 are supported upon spaced girders 11, 12 carried by end pedestals 16, Fig. 1, and an upper frame in the form of two girders 18 provides support for the rotary cutter which is carried by a frame 33 mounted on the underside of a plate 31 secured by screws underneath a slide 26. This slide has a dovetail connection 23 with the girders and is traversed along the latter by a nut 27 on the slide engaging the screw-threaded part 28 of a shaft 22 which is supported by the girders for rotation by an electric motor. The rotary cutter, which is flat-edged and in the form of a slightly-dished disc, is clamped by a coaxial bolt 66 between flanged member 67 journalled in the frame 33. One end of this frame is pivoted on lugs 34 on the underside of the plate 31 and urged by a spring 35 so that its opposite end is held against a positioning screw 36 depending from the plate. Guard plates 41 are fixed to the frame 33 on opposite sides of the cutter. The blades 14, 15 are secured to the girders 11, 12 by bolts 42 engaging slots in either the blades or girders, and may be positioned in a direction transverse of the girders by screws 44 in rails 43 fixed to the girders. The sheet 39 to be cut is supported by the blades 14, 15, rails 43 and guide bars 45, adjustable stops on the latter bars providing for correct positioning of the work. The blades 14, 15 may be inverted and moved end-for-end so that all their edges may be used in turn to co-operate with the rotary cutter. One or both operative edges of the blades may be bevelled to provide relief during cutting. In operation, the cutter 37 may be rotated either by the friction consequent upon its cutting traverse or it may be positively rotated. If desired, the connections of the motor driving the shaft 22 may be automatically reversed at each end of the traverse of the slide 26 so as to facilitate cutting the work into a plurality of strips. For grinding the edges of the blades 14, 15, the plate 21 with its depending frame 33 and cutter 37 is replaced by a member carrying a motor-driven grinding wheel (see Group XXIII). The Provisional Specification described also (a) the traverse of the slides 26 as being effected by a driven endless chain, (b) the mounting of the rotary cutter 37 in a supporting fork and its replacement therein by the abrasive wheel for grinding the blades 14, 15 and (c) the use of a raked blade having a vertical guillotine action instead of the rotary cutter.