Auxiliary lock with an extensible device

Claim 1

An auxiliary lock with an extensible portion, comprising: a cylinder provided with two positioning holes and a longitudinal slot, and having its outer circumferential surface surrounded by an extensible shell; said extensible shell being provided with an inner projection which can selectably extend into one of the two positioning holes in the cylinder and move lengthwise along the slot in the cylinder by turning the extensible shell and causing relative axial movement between the shell and the cylinder; a combining plate assembled with a rear section of the extensible shell and provided with a connecting plate connected with a moving plate; said moving plate also being connected with a dead bolt and being provided with a front round tube section which is received in the dead bolt, said front round tube section having a U-shaped slot and a reversed U-shaped slot for receiving respective portions of a pin; said dead bolt being movably contained inside the cylinder and having a hollow interior which receives the front round tube section of the moving plate, with said pin extending crosswise through a rear end of the dead bolt and said U-shaped slot and said reversed U-shaped slot in the front round tube section of the moving plate; and said pin connecting the dead bolt and the moving plate, and being capable of movement from one end of both the U-shaped slot and the reversed U-shaped slot to the other ends of both of the slots when the projection in the extensible shell moves from one of the two positioning holes to the other in adjusting the lock from a short length to a long length or reversely.