Finding a Solution for Bellows Coupling Failure

When a problem such as breaking bellows couplings threatens to halt a machinery production line, it is necessary to look beyond the obvious. In an application in which the coupling works on a Heidenhain encoder for an X-Y table that positions circuit boards, representatives of the user company and of Servometer determined that it was a flexing type failure rather than a torquing failure. There were two couplings per handling machine, and calculation showed that the peak torque transmitted through the coupling was 0.22 in.-oz. After a thorough analysis, it was clear that the existing bellows coupling was failing because of offset, since the failure was in the first convolution closest to the end piece.