초록 ▼

Methods and apparatus for ascertaining movement of a device from a first position to a second position couple a ratchet member and pawl combination to that movable device. Clicks indicative of the movement of the device are generated by effecting relative motion between the ratchet member and pawl i

Methods and apparatus for ascertaining movement of a device from a first position to a second position couple a ratchet member and pawl combination to that movable device. Clicks indicative of the movement of the device are generated by effecting relative motion between the ratchet member and pawl in accordance with the movement of the device from the first to the second position. An ascertainment is then made from the generated clicks whether the movement of the device has in fact resulted in the desired movement from the first to the second position. The invention is of particular utility in the monitoring of character segments in printing devices, but is not limited to such an application.

대표청구항 ▼

A method of ascertaining the existence of a predetermined relative position between a ratchet member and a leaf spring, comprising in combination the steps of: providing said ratchet member with ratchet teeth each having a projecting edge; providing a transducer element emitting an electric signal i

A method of ascertaining the existence of a predetermined relative position between a ratchet member and a leaf spring, comprising in combination the steps of: providing said ratchet member with ratchet teeth each having a projecting edge; providing a transducer element emitting an electric signal in response to bending; rendering said transducer element coextensive with part of said leaf spring; applying said leaf spring to the ratchet member and effecting relative movement between the ratchet member and the leaf spring in order to realize said relative position and to cause the leaf spring to ride up on a tooth at a time and bend the partially coextensive transducer element and to snap back off the projecting edge of the tooth; emitting with said transducer element an electric signal each time the bent transducer element snaps back after said leaf spring; and ascertaining from electric signals thus emitted an attainment of said relative position.