A bistable control mechanism effecting the movement between two parts of an apparatus between two bi-stable positions

摘要

An apparatus comprising a guide track member 400 having first and second guide track portions for a first part, a guide pin 402 for a second part and means to apply a lateral force force to the guide pin such as a first biaser 404. The first and second parts being for a portable electronic device such as a personal digital assistant (PDA) or mobile phone. The apparatus is configured such that the guide pin travels within the respective guide track first and second portions to provide respective first and second bistable configurations of the apparatus in which the first and second parts are held in relative positions to one another. The first biaser is configured to apply a lateral force to the guide pin to cause it to travel along the first portion of the guide track when moving from the first bistable configuration to the second bistable configuration and to apply a lateral force to the guide pin to cause it to travel along the second portion of the guide track when moving from the second bistable configuration to the first bistable configuration. The transition between the bistable configurations is provided by relative movement of the first and second parts in the same direction. The guide track may take the form of a heart-shaped cam track with a notch 414 providing one of the bistable positions and elongate section 410 providing a second of the bistable positions. The first bias means may be a u-shaped spring 404 or may consist of two springs (504, 505, fig. 5). A second biasing means such as a coil spring may be provided to bias the first and second parts toward the second bistable position. The first bias means ensures the pin travels around the guide track in a single direction and the track may thus be stepless and be in a single plane. The apparatus is preferably a push-push mechanism.