Patent ID: 7712344

Claim:
A key-changeable lock, comprising, in combination: (a) a lock housing, (b) a lock cylinder for rotation within the lock housing about a rotational axis, the lock cylinder including, (i) a locking block slidably mounted on a periphery of locking cylinder, and having a first working position and a second working position, wherein the locking block extends from the lock cylinder to engage the lock housing, thereby directly preventing rotation of the lock cylinder relative the lock housing in the first working position, and wherein the locking block at least partially retracts into the lock cylinder to allow rotation in the second working position, (ii) a toothed piece with a block groove, wherein the toothed piece is movable to allow or block retraction of the locking block into the lock cylinder and the toothed piece is positioned entirely within the lock cylinder in both the first and second working positions, (iii) a toothed slide that moves in the lock cylinder transverse to the rotational axis, the toothed slide having engaged and disengaged positions with the toothed piece, the toothed piece moves in a fixed relationship with the toothed slide when in the engaged position, and in an independent relationship when in the disengaged position, (iv) a sliding block that moves the toothed slide between the engaged and disengaged positions, wherein the sliding block is moved by the locking block via pins extending between the locking block and sliding block, and (v) a locking hole provided on or in the lock cylinder and into which a key is inserted, wherein insertion of a first key into the locking hole moves the toothed slide and in turn the toothed piece into the engaged position, so that the block groove allows retraction of the locking block into the lock cylinder, wherein rotation of the first key in turn rotates the lock cylinder, the locking block retracts into the lock cylinder sliding into the blocking groove, wherein retraction of the locking block into the lock cylinder, i) prevents the toothed piece from moving with respect to the locking block, and (ii) slides the sliding block linearly in a direction perpendicular to the rotational axis to disengage the toothed slide from the toothed piece, and wherein removal of the first key and insertion of a second key moves the toothed slide to establish a new engaged position between the toothed slide and the toothed piece, so that the second key now locks and unlocks the key changeable lock.