Thomas A Braun

US Patent:

20070039173, Feb 22, 2007

Filed:

Aug 4, 2005

Appl. No.:

11/197111

Inventors:

Thomas Braun - Grandville MI, US
Venkatasubramanian Ananthanarayanan - Beavercreek OH, US
James Payne - Grand Blanc MI, US

International Classification:

B21D 53/84
B23Q 3/00

US Classification:

029888100, 029464000

Abstract:

In a method and apparatus for staking a hardened shaft in bores in a hydraulic lifter body, the shaft is inserted into the bores such that the shaft ends are substantially flush with the bore exits which are slightly chamfered to receive staked material displaced from the shaft. Mechanical rams that also define a first electrode are advanced axially of the shaft into contact with the shaft ends. A second electrode is brought into contact with the lifter body. Electric current is passed between the electrodes, causing resistive heating of the body and the shaft ends. The time and applied amperage are sufficient to cause softening of the shaft ends, at which time the current is switched off, and the first electrode is then driven against the shaft ends, causing the ends to be radially expanded into the chamfers. The remainder of the shaft is not softened nor retempered.