Patent GB-595782-A (GB)
Title: Improvements in and relating to the drawing of metal tubes and the like
IPC: B21C1/32
Filed: 1945-07-02
Abstract: 595,782. Drawing. WELLMAN SMITH OWEN ENGINEERING CORPORATION, Ltd., BROOKS, C., KUPHAL, E. G., and MARNIE, J. July 2, 1945, No. 16835. [Class 83 (iv)] [Also in Group XXX] In apparatus for drawing metal tubes having a number of mandrels movable from a loading position to a drawing position in front of the drawing die, the loading of the blanks on to the mandrels and the drawing of the tubes is effected in such a way that both the blanks and the tubes move along substantially horizontal axes. The blanks are fed manually on to a series of supports or skids 64, Figs. 2 and 12, along which they are moved by intermittently operated conveyers 65. The skids are formed with V-shaped recesses 95 for receiving a single blank which is then lifted by arms 97 so that it moves down inclines 86 and on to a series of rollers 13. The arms 97 are pivoted to supports 98 of the machine and are operated by pistons in compressed-air cylinder 99. On the upward stroke a blank is lifted out of the recesses 95 and on the down stroke pawls operate ratchets 102 to impart a feed movement to the conveyers 65. The rollers 63 are driven by a chain 66 to feed the blank between two series of gripping pads 61, Fig. 10, which in turn feed it on to the mandrel 6 at the loading position. The pads 61 are carried by endless chains 62 carried by sprockets 80 driven from a motor 68 coupled through reduction gearing to meshing gears 75, 76 which also mesh with gears 78 driving gears 79 on the spindles of the rear sprockets 80. Gear 75 also drives a sprocket 77 of the chain 66. The sprockets 80 are carried by triangular frames 82 mounted at 83 on arms 84 pivotally mounted on the spindles of gears 75, 76 and carrying intermeshing toothed quadrants 86. The lower arm 84 is extended and coupled to the piston of a compressed-air cylinder 90 by which the pads may be moved into and out of gripping engagement with the blank. The machine has two mandrels 6 supported at the rear in an anchorage 13, one above the other. For the greater part of their lengths they are carried by troughs 59 which are inclined so that one mandrel is in line with the die 1 and the other in line with the loading device and so that the forward ends 15 of the mandrels are in the same horizontal plane. At each of three positions A, the troughs are carried by horizontal bars 58, Fig. 7, connecting the ends of parallel levers 54 pivoted on a pedestal 14, the three sets of parallel levers being interconnected by a shaft 56 so that a movement of the middle set by the piston of a compressed-air cylinder 60 causes simultaneous actuation of the other two sets to effect an interchange of the positions of the two mandrels. Owing to the inclination of the mandrels, the levers 54 are longer at the position nearer the die and shorter at the position nearer the anchorage. The anchorage comprises a housing 13 in the upper part of which are two fluid pressure cylinders 35, Fig. 3, each integral with or secured to a slide 24 having limited longitudinal movement within its housing. Each mandrel has its head 45 held in a slotted block 44 slidable along grooves in forwardly extending side members of the slide 24, the block being connected to the rod of a piston 40 operating in one of the cylinders 35. The mandrels can be advanced to the drawing position or withdrawn by means of pressure fluid which may be admitted to either end of the cylinders through inlets 47, 48 under the control of valve gear, not shown. To permit fine adjustment of the position of each mandrel at the die, each cylinder is formed with an external screw thread and carries a nut 39 held against longitudinal movement by the housing and adapted to be rotated to effect longitudinal movement of the cylinder and mandrel by a sprocket 53 and chain 52 operated from hand wheels adjacent the die through shafts 49. Alternatively the advance and withdrawal of the mandrels may be effected by means of a nut driven by an electric motor, the mandrel being threaded through the nut. The blanks are drawn over the mandrel and through the die by means of a carriage 5 which is moved along tracks 4 by an endless chain 7 driven by an electric motor 16 and is returned after a drawing operation by another chain 8 driven by a smaller motor 21. As a tube is drawn it is supported on a number of skids 109 one of which is shown in Fig. 12. Each skid is carried by two levers 118, 121 pivoted on fixed axes 119, 122 respectively and is adapted to be moved from the horizontal tube receiving position to the discharging position shown in full lines by means of links 116, 117. The former is fixed to a shaft 115 adapted to be turned by the piston of a compressed air cylinder 111 and the latter having a lost-motion pin-and-slot connection with the lever 121. At the end of a drawing operation the piston is actuated to move all the skids to the discharge position after which the piston is returned but the skids are retained in the discharge position by a series of trip levers 125 which engage projections 126 on the levers 121. As the carriage 5 moves along the track during the next drawing operation, a depending projection 127 successively actuates the trip levers whereupon the individual skids return to the horizontal position under the action of counterweights 124. All the parts of the apparatus may be actuated from a position adjacent the die where they are under the control of the operator. Specifications 595,778, 595,779, 595,780 and 595,781 are referred to.