Abstract: The present invention is a retracting mechanism for use in combination with a tape recorder. The tape recorder includes a base plate, a capstan drive for driving a magnetic tape in a tape cassette and an electronic circuit. A magnetic head is disposed adjacent to the magnetic tape and is electrically coupled to a electronic circuit. A slidable mount for mounting the magnetic head is slidably coupled to the base plate so that the magnetic head may move bidirectionally in a direction orthogonal to the direction which the magnetic tape travels across the face of the magnetic head in order to engage the magnetic tape. The retracting mechanism includes a lever arm which is pivotally coupled to the base plate and disposed adjacent, but not continguous to, the capstan drive. A pinch roller the axis of which is rotatably coupled to the lever arm. A first spring resiliently biases the lever arm so that the pinch roller pinches the magnetic tape against the capstan drive.

Abstract: A unitary self-contained electronic combination lock is provided which includes a dead bolt manually operable from one side and operable from the other side only in response to insertion of a data combination card carrying a unique binary code in the form of selectively positioned metallic spots. Sensors located within the unit generate a binary 1 or 0 signal in response to the presence or absence of a metallic spot adjacent each sensor. The lock combination code is automatically changed to the data card's code upon insertion of a card having a code combination which includes part of the lock's code so that the previously issued cards will no longer operate to unlock the door. In this manner, the authorized code for each lock unit is automatically and independently changed to render inoperative all previously issued data cards.