Types of Door Latches

Understanding the mechanics will help you lock your doors with assurance

By Don Masters

Photo by iStockphoto.com

Door latches are designed to hold a door shut and possibly lock it. While there are a variety of styles of latches available, few stray from a basic design. Either they have a heavy spring, or they use a manual connection device to hold the door in the closed position.

Standard Latch

A standard door latch is a manual mechanism made of two pieces, usually metal, designed to connect and hold the two parts until manually released. Installation includes attaching one of the pieces to the door and one to the doorjamb. As the door closes, the two connect and remain together until manually released. The method of release will depend on the design of the latch. Several versions of manual mechanism latches exist on the market. Some automatically latch, making use of gravity as they make contact with each other, and some require some form of manual connection assistance, such as turning a handle or pulling a connecting string.

Dead Latch

A typical household door lock configuration uses a dead latch to hold the door closed. It utilizes a beveled metal spring-loaded plunger that presses inward when pressing against the doorjamb striker and through the assistance of the spring, presses outward into a receiving hole in the jam. Typically, to release the latch, you turn a handle or doorknob attached to the mechanism.

Sash Lock

The sash lock is a combination lock and latch mechanism. The latch catches and holds the door shut using a heavy spring and striker plate. This type of latch uses a metal plunger spring loaded to latch the door. The lock portion of the sash lock uses a large metal plunger to connect the door to the doorjamb. A key or small handle connects the plunger to a rotating mechanism, allowing the user to open or extract the plunger at will. It is not spring loaded and requires manual movement to open and close the plunger. With the door held in the closed position by the latch, the user can manually lock the door by turning the key or a small handle.