Push button construction for telephone selector panels - has split spring ring opened out after predetermined button movement

摘要

The push-button (2) has a central projection guided in a cylindrical bore in a sleeve (6) projecting from the interior of a casing (1). A split spring ring (3) surrounds the sleeve (6) and a cam (41) is formed on a control ring (4) within the button (2) in line with the gap in the spring ring (3). A compression spring (5) is located between the control ring (4) and a seat (31) on the split rung. When upon depression of the button (2) the force of the spring (5) is overcome the cam (41) enters the gap in the spring ring (3) and spreads the ring, enabling the button to be fully depressed. The action of the cam on the spring ring is instantaneous, and is facilitated by the provision of shoulders (32) on the spring ring that are matched to the shape of the cam.