An accessory for the security locking of a lock. A dead-boltable external door lock is capable of being locked with the accessory from inside in such a way that the lock cannot be opened with a key or a picklock. The lock includes a lock body, a twist knob, a key cylinder, and a shaped spindle present between the twist knob or a handle and the lock body and in engagement with a lock mechanism. An accessory is between the twist knob or a handle and the lock body and the accessory includes a body and a safety latch propped on the body, which is movable from a security locking release position to a security locking position in which the shaped spindle is locked in a non-rotatable manner against turning effected with a key or a twist knob or a handle.

A door lock for a handle, comprises a housing, a rotatable connector inside the housing, a first elastic element and a second elastic element both arranged inside the housing. The rotatable connector is interacted with the handle. The first elastic element is at least configured to provide a restoring force for the handle to return to its origin position when the handle is rotated upward to lock the door, and the second elastic element is configured to provide a restoring force for the handle to return to its origin position when the handle is rotated downward to unlock and open the door, as well as to provide enough resistance to remain handle at its origin position when the handle is released. The door lock is effort-saving for the users to rotate the handle upward, and also adapted for various handles having different weights, to be remained at the origin position when the handle is released.

The present invention relates to the field of lockset and provides a lock body a latch bolt installation structure comprising a latch bolt body having a driving part and a latch part, wherein the latch part is detachably connected with the driving part. The latch part is configured with a male part inserting into a female part on the driving part; the female part comprises a first installation position and a second installation position for installing the latch part; when the latch part is installed at the first installation position, a flat surface of the latch part faces towards a first direction; when the latch part is installed at the second installation position, the flat surface of the latch part faces towards a second direction which is opposite to the first direction. The present invention is advantageous in fast reversal of the installation of the latch bolt as well as the construction progress control and user experiences.

A door lock for a handle, comprises a housing, a rotatable connector inside the housing, a first elastic element and a second elastic element both arranged inside the housing. The rotatable connector is interacted with the handle. The first elastic element is at least configured to provide a restoring force for the handle to return to its origin position when the handle is rotated upward to lock the door, and the second elastic element is configured to provide a restoring force for the handle to return to its origin position when the handle is rotated downward to unlock and open the door, as well as to provide enough resistance to remain handle at its origin position when the handle is released. The door lock is effort-saving for the users to rotate the handle upward, and also adapted for various handles having different weights, to be remained at the origin position when the handle is released.