Door latch is an integral part of door hardware. Typically, door latches do not lock; however, some latches are available with a key-locking mechanism or can be secured with a padlock. Latches with a locking option can only be opened from the outside with a key. In order to complete the door ensemble, door latch consist of strike plates, tube latches and rim lock plates. However, there are latches that can also be opened without a key.
Mostly metals are used for making door latches. Some of the common materials used in the process include:
Door Latch Mechanism
The working principle of a door latch is relatively simple, compact and easy to install. A typical door latch mechanism has a pivoted latch, which is disposed between a retaining solenoid and a four-bar toggle linkage.
- The toggle linkage is meant for connecting the operating system of the solenoid to the latch.
- The toggle linkage is also provided with an under-the-center arrangement in a direction opposite to the solenoid in the latched position.
- This offers considerable mechanical advantage to strengthen the holding force of the solenoid.
- When the solenoid is de-energized and pressure is applied to open the door, the latch pivots and the toggle linkage collapses to release the keeper bar.
Door latches should be chosen in such a way that they fit exactly with the strike plates.
- The quality of the metal chosen for making latches is also important as the security of the house depends on latches.
- The finish of the door latch should go with the overall impression of the door and the house.
- The overall finishing of the door latches hardware should be very smooth so that it does not hurt any individual while operating it.
Some door latches have an inside release that is a component on the inner side of the latch that allows it to be actuated. Again door latches have mounting holes or slots for securing them to doors, drawers, or cabinets.
- There are recessed latches that are designed to be mounted in an indentation in the housing.
- Latches that contain gaskets prevent the entry of environmental contaminants when used under pressure.
- Weather resistant door latches are also available.
Depending on the door on which they are used door latches can be of the following types: Cam Latch
- Compression Latch
- Dead Latch