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Domed Actuator Backstops

IP.com Disclosure Number: IPCOM000044724D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Whitehead, K: AUTHOR

Abstract

Contemporary wire matrix printer heads contain wires actuated into motion by electrically operated solenoid devices. Referring to Figure 1, current applied to coil 1 establishes a magnetic field that propels armature 2 and its connected print wire 3 towards a not-shown print ribbon and paper. Backstop 4, made of a hard wear resistant material, provides a stop surface for halting the returning armature and absorbing its return impact energy. To sustain the operational life of these elements, it is customary to coat the backstop surface with a petroleum base oil acting to reduce wear (Figure 2), but having the undesirable accompanying effect of causing the armature to stick to the backstop and fail to operate if it has been inactive for some time.

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Domed Actuator Backstops

Contemporary wire matrix printer heads contain wires actuated into motion by electrically operated solenoid devices. Referring to Figure 1, current applied to coil 1 establishes a magnetic field that propels armature 2 and its connected print wire 3 towards a not-shown print ribbon and paper. Backstop 4, made of a hard wear resistant material, provides a stop surface for halting the returning armature and absorbing its return impact energy. To sustain the operational life of these elements, it is customary to coat the backstop surface with a petroleum base oil acting to reduce wear (Figure 2), but having the undesirable accompanying effect of causing the armature to stick to the backstop and fail to operate if it has been inactive for some time.

This sticking effect is eliminated presently by providing a spherical shape 5 at the backstop surface (Figure 3). The spherical radius of the backstop surface should be large (e.g. on the order of 10 times the armature diameter) to avoid the possibility of creating other wear problems due to side loads at the contact position.

Disclosed anonymously

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