An "Oldham Coupler" is way to transfer torque between two parallel but
not-quite-collinear shafts. It has three disks, one coupled to the
input, one coupled to the output, and a middle disk that is joined to
the first two by tongue and groove. The tongue/groove on one side is
perpendicular to the tongue/groove on the other. Often springs are
used to reduce backlash of the mechanism. The coupler is much more
compact than, say, two universal joints. But: who was Mr. Oldham?
Google searches turn up the device's inclusion in R-390A radios and
astronomical instruments, but nothing about its inventor. Tim. (who
otherwise wonders who takes care of the caretaker's daughter while the
caretaker's busy taking care.)