Push button selection keyboard for telephone set - has two orthogonal sets of conductors with L=shaped lateral arms acting as spring-contact crosspoint switches

摘要

The keyboard has a switching matrix comprising two orthogonal sets of parallel conducting strips (1-7). The sets lie in two planes one above the other and insulated from one another. The strips in the first set have lateral L-shaped arms (9) projecting from them and acting as leaf-spring contacts. The push-buttons (8) are located above the ends of these arms and, when depressed, press the ends of the arms down onto the corresp. conducting strips in the second set of strips immediately below. The arms therefore act as crosspoint switches. Needs no separate contact plates and offers simplicity but with reliability and versatility.