GB858726A - Improvements in and relating to machines for hot-forming bar stock - Google Patents

Abstract

858,726. Forging. GESELLSCHAFT FUR FERTIGUNGSTECHNIK UND MASCHINENBAU G.m.b.H. Sept. 12, 1958 [Sept. 14, 1957], No. 29252/58. Class 83 (4). A machine for hot forming bar stock comprises feeding means 46-49, Fig. 4, for the stock, electric induction heating means 89 through which the stock is fed, temperature responsive detecting means for detecting when the stock has reached a predetermined temperature and then starting the feed, and control means for causing dies 1 to act upon the stock and then retract therefrom. The bar stock is fed through the heater 89 and between opposed reciprocating forging dies 1 by hydraulically-actuated spring- biased pivoted gripping tongs 46, 48 mounted on a carriage 68 which is reciprocated by an hydraulic piston 65 connected thereto through an adjustable sleeve 67 which varies the feed stroke. When the stock has reached a predetermined forging temperature, a pair of pyrometers 96, Fig. 3 (not shown), close a relay circuit 98, Fig. 11 (not shown), which opens solenoid valves causing tongs 46, 48 to close on the stock and then piston 65 to feed it forwardly and bring the heated portion between the forging tools. Tongs 46, 48 are then opened and simultaneously stationary tongs 47, 49 are closed to hold the stock during forging. Similar reciprocable and stationary tongs 50-53, Fig. 3 (not shown), are provided at the rear of the machine, the reciprocable tongs being connected to piston 65. Carriage 68 and tongs 46, 48 then return to their initial position and may repeat the feed one or several times before forging takes place. Actuation of a limit switch 72 by carriage 68 causes solenoid valves to supply hydraulic fluid between opposed pistons 40, Fig. 1, which act through adjustable linkage 38, 37, 36 and cause work-holders 32 to close on to the bar and hold it between the dies 1. The holders 32 are liquid cooled and carry nozzles for spraying, cleaning and anti-sticking liquid on to the dies. The dies are removably mounted on water-cooled die holders 2 carried by reciprocable slides 3 actuated by eccentrics 5 on drive shafts 6. These shafts are eccentrically mounted in rotatably adjustable bushes which have gear teeth meshing with a central common gear 11, Fig. 6 (not shown), actuated by an adjustable rack 12 driven by an hydraulic piston in cylinder 14; movement of the rack is damped by a dashpot. Each slide 3 may carry a pre-forming and a finishing die. Actuation of limit switch 72 also causes rack 12 to move the continuously reciprocating dies inwardly to engage and forge the stock. After a delay determined by a timer, the tools are withdrawn by the rack and the work-holders 32 are then withdrawn. Limit switches 18, 44, 45 in the relay circuit are closed when the tools and work-holders are fully withdrawn and thus prevent premature feed. The feed mechanism and heater 89 are mounted on a withdrawable carriage 54 to facilitate their maintenance. The machine is mounted on trunnions 31 in pedestals 30.