When pedal 1 is depressed, piston 2 moves downward and fluid under pressure is delivered through check valves 3 and 4 and pipeline 5 to servomotor 6. At this, piston 7 moves downward and plunger 8 with a welding die descends onto the contact heads, located on the base of the clamping devices. When pedal 9 is depressed, piston 10, of smaller diameter than piston 2, moves downward, delivering fluid through valve 4 and pipeline 5 to servomotor 6, firmly clamping the components to be welded. Check valve 11 is closed during operation of the clamping devices. To release the components and to raise the welding dies, pedal 12 is depressed. This opens valve 11 and fluid is discharged to tank 13. The welding dies are raised by springs 14. Check valve 15 prevents the fluid from being discharged to the tank while pressure is being developed. When pedal 1 is raised by spring 16, fluid from the tank is drawn in under piston 2. Check valve 3 is provided to prevent excess pressure in the system for advancing the clamping devices. Check valve 4 prevents a possible reduction in pressure in the system of clamping devices when pedal 9 is released and piston 10 is moved upward by spring 17.
$4292$CHP,GC$