Tactile indicator for bistable states - has button operated by electromagnetic actuator and locking device

摘要

The tactile indicator comprises a reading table which is perforated to allow a button to protrude. The non-magnetic button is attached to a permanent magnet. The magnet is supported on a rod of non-magnetic material such as self-lubricating plastics which passes through the core of an electro-magnet coil. At the lower edge of the core of the electro-magnet is a tilting segment or wedge to which is attached a permanent magnet. The wedge is balanced so that it normally prevents the rod from dropping to its lower position. When a DC potential of the correct polarity is applied to the coil, the upper permanent magnet is attached downwards and at the same time the tilting wedge is repelled sideways to allow the rod to fall.