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.
The engineers followed up by determining the maximum offset, and a Servometer bellows coupling was chosen that could handle the offset, the small amount of possible bending, and the small mount of torque. The choice was confirmed by another division of the same company, which had been using the recommended coupling without encountering a problem. Servometer says the company is using the couplings for new handling-machine production.
This work was done at Servometer Inc. For more information, contact Tom Guarino, Engineering Sales Manager, 501 Little Falls Rd., Cedar Grove, NJ 07009-1291; (973) 785-4630, ext. 243; fax: 800-785-0756 or 973-785-0756.