Inventors:
Eric Easterbrook - Kent WA, US
Milton Sigelmann - Lake Forest Park WA, US
Radford Goodloe - Kent WA, US
International Classification:
B21D037/00
Abstract:
Control systems for indenters used in cold working processes, and in particular, for StressWave cold working of metal workpieces. Load on an indenter is increased by increasing the force applied, such as by pressure in a hydraulic reservoir acting on a piston. When the load reaches a desired limit, as may be calibrated by the pressure in the fluid reservoir responsive to the piston being driven by the indenter, then a pressure relief valve allows the fluid to flow from the cylinder to a hydraulic reservoir, thus allowing the indenter shaft to move away from the workpiece. Then, on recycle of the apparatus, an automatic control system reacts to such movement and pumps fluid back to the reservoir, and thus returns the indenter shaft to a pre-determined position. In one embodiment, the pressure relief valve is integrated into, or attached to, the indenter. Other embodiments are disclosed for control of various compound or simple indenters.