Patent GB-737087-A (GB)
Title: Automatically-operating machine for drawing and severing bar material
IPC: B23D25/02
Filed: 1952-01-08
Abstract: 737,087. Drawing, straightening and cutting bar stock. SCHUR, H. G. Jan. 8, 1952, No. 616/52. Class 83 (4). A machine for drawing and cutting bar material wherein the work is drawn through a drawing block by means of a plurality of drawing slides and is cut to length by a severing device which moves a distance with the drawn material when the desired length of bar is reached the drawing slides and severing device being reciprocated parallel to the drawing axis by rotatable cam discs, is characterized in that the cam discs are carried on parallel shafts arranged transversely of the drawing axis such that one or more pinions on a driven shaft parallel to said cam shafts are arranged to drive gear wheels on the cam shafts at the same time. The bar material passes from a supply reel through a straightening device 2 comprising two groups of rollers arranged in parallel paths and each group can be selectively brought into alignment with a drawing die 8 so that as the bar 1 is being drawn a second bar 3 can be fed into the other group of rollers. As soon as the drawing of bar 1 is completed the straightening device is changed over so that the bar 3 is in position for drawing through the die 8. Each group of rollers is adjusted by a hand wheel 4, 5. The slides of the draw bench are driven by an electric motor 9 through gearing which includes a pinion 10 on a transverse shaft said pinion engaging gear wheels 12 and 27 on transverse parallel shafts 16 and 17 respectively. The shaft 16 carries two cams 13 and 14 arranged at 180 degrees relatively to each other said cams co-operating with levers 19 and 18 connected to the drawing slides 7 and 6 by means of drawbars 22 and 21 respectively. The slides move alternately in the drawing direction and ensure a uniform speed of feed. Each of the levers 18 and 19 have a second lever arm which coacts with a further cam disc 25 or 24 respectively to return each drawing slide to its initial position. The shaft 17 carries a cam 15 and a return cam 26 both operating a lever 30 which by means of a draw bar 23 reciprocates the cutting slide 28 when a magnetic clutch 20 on the shaft 17 is engaged. For varying the speed of the machine during running friction clutches 36 and 37 are provided on the driving shaft 9a the former being connected to a pair of gears 39 and the latter to gears 38 said gears having different transmission ratios. By using a pole-changing motor 9 four different drawing speeds are obtained with the two clutches. The drawing die 33 is secured in an adjustable support 34 (Fig. 3) by a nut 35 said support having a spherical surface which engages a similar surface in the machine frame. Shearing.-The shearing device comprises a tapered housing 89 in which two wedge-shaped slides 41 and 42 are arranged on rollers and blade carriers 43 and 44 pivoted on the slides 41 and 42 carry blades 45 and 46 respectively. A spring 47 ensures that the cutting edges of the blades are adjacent to one another and the blades are supported by members 48 and 49 on the slides 41 and 42 respectively. Bars 56, 57 for guiding the slides are fixed to the housing 39 and engage in grooves on the underside of the slides. When the clutch 20 is engaged the slides 41, 42 are moved by means of a rod 50 attached to the slide 42 the slide 41 being driven by the blade 46 engaging behind the blade 45. The blades thus move forwards and towards one another to shear the bar 51 after which the members 48 and 49 engage abutments (not shown) so that the blades slip off said members and the spring 47 swings the blade supports 43 and 44 outwardly until the blades bear on the slides 41 and 42 the opening between the blades then being sufficient to clear the drawn material and so allow the slides 42 and 41 to return to their initial position. Before the slides reach their initial position pins 52 and 53 engage stop bars (not shown) which force the blades 45 and 46 away from the slides to enable springs 54 and 55 to push the members 48 and 49 between the slides and the blades in readiness for the next shearing operation. In an embodiment of the shearing device wedgeshaped slides 64 and 65 carrying blades 66 and 67 are displaceable in a tapered housing 61 along wedge-shaped bars 62 and 63. The blades 66, 67 are displaceably mounted in the slides to move transversely of the bar material being drawn and are held in position on spring-loaded support members 68 and 69 by springs 80 and 81 respectively. The bar material passes through a guide tube 72 and a conical member 73 and between the blades 66 and 67. As soon as a desired length has passed between the blades the shearing clutch is engaged and a slide 74 by means of links 75 and 76 moves the slides 64 and 65 to the right in Fig. 5 and the blades sever the bar material. After the severing operation a bell-crank lever 77 (Fig. 5) strikes a stop 78 and withdraws the support 68 so that the blade is retracted outwardly from the bar material by the spring 80. In the embodiment shown in Fig. 4 the member 69 engages a spring- loaded stop 79 and the blade retracts into a recess in the member 69 and is thus also withdrawn from the bar. As the slides return to their initial positions the blades slide along bars 82 and 83 and remain equidistant from the drawing axis of the machine whereas the slides move outwardly until the spring-loaded supporting members 68 and 69 are able to engage once more behind the blades. The slides are preferably of different inclinations and if one slide has no inclination the blade may be rigidly mounted in such slide and the intermediate member or supporting member omitted.