Digital adjuster esp. for setting number wheel counters - with knob needing positive outward pull before setting can be changed

摘要

A digital adjuster comprises a rotary knob, an adjusting element coupled to a shaft such as a potentiometer shaft and to a number wheel counter through a toothed gear, and a releasable coupling between the knob and the adjusting element. The coupling (32, 34) brought into operation by pulling the knob (12) outwards. Pref. the knob fits over the adjusting element and has a toothed rim (32) which engages with a mating rim (34) on the adjusting element when the knob is pulled outwards. The need to pull the knob outwards before adjustment means tht accidental alteration of the setting is unlikely.