Abstract: A key mechanism comprises a rack and an external force key member, the lower part of the rack disposed with a transmission pinion on one side and ratchet means on the other side. The ratchet means comprises a first ratchet and a second ratchet arranged consecutively to one another from the top down. The rack is provided with a first step and a second step arranged consecutively to one another from the top down. An elastic retaining member is mounted on the ratchet-side of the rack, and a rack returning spring and key returning spring are respectively mounted on the rack and the external force key member. The elastic retaining member is brought into clamp connection with the first or second ratchet in the lower part under the press action on the external force key member. The key mechanism increases the range of possible password settings of the code lock.

Abstract: A code changing mechanism for a mechanical combination lock, comprises function keys; two rows of code number keys on the lock body; a code-changing rack; an intermediate gear; a code-changing lock core with keyhole; and gear modules connected with each code number key, each gear module comprises a code-changing gear and controlling chip. There is a groove for resetting code provided on the gear; the chip inserted in the groove forming a code reset site; a code free site provided between the chip and gear; a left and a right straight rack; and the rack engages with a corresponding row of code-changing gears. The lock core coaxially connects with the intermediate gear, the intermediate gear engages with two opposing code-changing gears thereof. A movable sheet is under each of the keys. The code is changeable without disassembling any component, making the mechanism convenient, swift, flexible, reliable, with robust anti-crack capability.

Abstract: A code changing mechanism for a mechanical combination lock, comprises function keys; two rows of code number keys on the lock body; a code-changing rack; an intermediate gear; a code-changing lock core with keyhole; and gear modules connected with each code number key, each gear module comprises a code-changing gear and controlling chip. There is a groove for resetting code provided on the gear; the chip inserted in the groove forming a code reset site; a code free site provided between the chip and gear; a left and a right straight rack; and the rack engages with a corresponding row of code-changing gears. The lock core coaxially connects with the intermediate gear, the intermediate gear engages with two opposing code-changing gears thereof. A movable sheet is under each of the keys. The code is changeable without disassembling any component, making the mechanism convenient, swift, flexible, reliable, with robust anti-crack capability.