Improvements in or relating to apparatus for applying pressure to the hydraulic installations of hydraulically controlled electric welding and other machine tools

摘要

617,887. Electric welding; metal-working presses. SOC. ANON. DES USINES CHAUSSON. Nov. 9, 1945, No. 30005. Convention date, Nov. 23, 1944. [Class 83 (iv)] [Also in Group XXVIII] Hydraulically-controlled machine tools, particularly electric resistance welding machines, have the pressure in the hydraulic system applied by a plunger directly connected to an electromagnet. Application to riveting- machines is mentioned. Movable spot-welding electrodes 44 to 48 co-operate with fixed electrodes 49 in succession as determined by pressure in cylinders 43 admitted by valves 29 controlled by a cam-shaft 54 geared to a shaft 59 driven through a clutch 62 from a motor 64. The valves 29 make connection with a cylinder 2 having a plunger 3 directly connected to a rod 4 carrying the armature 5 of an electromagnet 8. A solenoid 16 retracts the armature after a pressure stroke. If the stroke of the plunger 3 increases, due to wear of the electrodes &c., excessive pressue due to near contact of the armature and magnet is avoided by an opposing spring 12 brought into action by contact of the parts 10, 11. The cycle is started by closing a switch 70, a solenoid 69 then rocks a lever 66 against a spring 67 allowing the spring 65 to close the clutch 62. A second cam-shaft 76 is driven from the shaft 59 and makes as many turns for one turn of the shaft 54 as there are electrodes 48. The cam-controlled switch 80 energizes the electromagnet 8 and causes an electrode to close on the work. Welding current is applied by the switch 81 and the welding circuit is broken by an automatic condenser switch (not shown). Opening of the switch 80 closes a switch for the solenoid 16. When all the electrodes have functioned, a cam 61 opens the clutch 62 and the machine stops. The work is then re-set for a further series of welds.