Door Latches

Door Latches

Door latches are a type of mechanical hardware used to fasten doors and keep them shut. A door latch uses a fastener attached to two ordinarily separated surfaces, most often the door and the frame, to prevent the door from swinging while still allowing normal operation when the latch is released. Though latches have traditionally worked in conjunction with locking mechanisms, recent latches combine both latch and lock into one piece of hardware. Door latches may be employed both on interior and exterior doors and are implemented in the design of almost every swinging door today. Most homes, offices, industrial settings and buildings that use standard doors use some variation of door latch. Additionally, these mechanisms are used in the auto industry and several household appliances. A dishwasher, for example, uses a door latch to keep from falling open while in use. The wide range of use is mirrored by the many different door latch designs available.

Commonly made of sturdy metals such as zinc and stainless steel, several manufacturers also offer plastic door latches. No matter the material, there are three basic components to door latches, which all range in design and complexity. In general, separate plates are attached to both the door and the adjacent frame. One plate, typically that of the frame, has an internal notch, external loop or groove. Another component, most often a bar or hook, attached to the door plate is left free to either swing or slide into the notch, loop or groove. A knob or lever is attached to the sliding portion of the door latch for retracting and extending the free moving component. When extended, the latch holds the door in place. Retracting allows ordinary separation and use of the door. The components of a door latch are commonly stamped pieces that are later assembled and spot welded, though the process differs slightly for each type of latch. Mortise, dead, rim and spring loaded are among the most common types of door latches.