Patent GB-288488-A (GB)
Title: Improvements in processes and apparatus for forging and roughing out iron and steel bars by electricity
IPC: B21J9/08
Filed: 1927-10-03
Abstract: 288,488. Giacchino, E. Oct. 3, 1927. Forging-machines.-In a process for upsetting metal bars wherein the bar is heated between two electrodes and pushed through one of the electrodes serving as a guide up against the other electrode serving as an anvil the distance between the electrodes is increased during the operation so that larger masses may be upset. As shown in Fig. 6 the bar 1 is moved by the pusher 3 through the guide electrode 4 against the anvil electrode 2 and upset to the form shown by holding the anvil 2 stationary to form the first bulb, then moving it at constant speed to form the cylindrical part and again holding it stationary to form the second bulb. The guide 4 may be moved in the opposite direction; such movement is necessary when the anvil is kept stationary for considerable periods or moved forwards to ensure sufficient length of bar between the guide and upset portion to prevent burning. Many other shapes, such as conical, may be formed by suitably varying the movements of the electrodes, and curved, eccentric, or inclined shapes may be produced by moving the anvil transversely. In the arrangement shown in Fig. 7 the anvil electrode 2 only is movable. The pusher 3 is actuated by the ram 5 of the hydraulic cylinder 6 and the anvil 2 is supported by the ram 8 of a second hydraulic cylinder 9 which is fitted with a cock 10 opened by a cam 14 on a rod 11 operated by the pusher 3 so as to permit backward movement of the anvil 2 at a rate determined by the rate of discharge from the cylinder 9. The heating of the bar is regulated by a main controller 16, which brings any number of the sections of the primary winding of the transformer 15 into the circuit and by an auxiliary controller 18. In the arrangement shown in Fig. 8 the anvil 2 is stationary and the guide 4 is moved in a direction opposite to the bar 1 by means of a double pinion 10<1> engaging racks 9' and 14<1> on the guide 4 and rod 11. The constructional form of apparatus shown in Fig. 10 comprises an accumulator 30 communicating by a conduit 35, control device 34 and conduit 36 with the rear end of the hydraulic cylinder 6 for operating the ram 5, the front end of the cylinder 6 being also in communication by a conduit 37 with a lower pressure accummulator 31. A branch of the conduit 37 leads to the lower end of another cylinder 38 operating a lever 39 for closing the sections of the guide electrode 4 on the metal bar; another conduit 40 leading to the upper end of the cylinder 38 from the control' device 34 is put in communication with the higher pressure conduit 35 when the work is completed to release the guide electrode. Another branch of the conduit 37 communicates. with the front end of a cylinder 43 which forms a closed fluid system with the cylinder 9 and pipes 42, the latter having an interposed valve control device 45 for regulating the fluid flow in the closed system and thereby the rate of movement of the anvil 2. An operating device 5 enables the anvil 2 to be displaced transversely for the production of curved shapes. The valvecontrol device., shown in Fig. 11, comprises a number of cam discs 46 on the spindle 47 engaging a number of valve rods 48 for opening a series of valves 49, the whole mounted in a casing connected by the pipes 50, 51 to the pipes 42. An alternative form of valve control consists of a cylinder with a hand-operated piston, the cylinder being provided on its inner wall with longitudinal grooves increasing in cross section from one end of the cylinder to the other. The guide electrode is formed of two parts 52, Fig. 13, with longitudinal races 54 for a number of balls 53 adapted to engage the bar 1.