In their simplest form, latches are fasteners designed to join two objects together on a temporary basis so they can be opened and securely closed. It's relevant to note that they differ from the locks typically found on doors and windows, though some feature keys. These simple mechanical devices come in many forms, so it's important to consider intended use before making a purchase.
Common Uses for Latches
Most doors and windows feature mechanical locks rather than latches. That said, some doors are also latched. Latches can also be found on:
Common Latch Types
Once customers have a good idea of their intended applications, they can start investigating options. There are five common types of latches, each of which is described below.
Slide bolt latches are similar to deadbolt locks. This common form of industrial door latch consists of a single bolt that extends into a locking mechanism on the door jamb. The strike plate features one or more separate catches that allow the lock bolt to be engaged only when the door is closed and prevents retraction by force. The average weld on trailer gate latch is a slide latch.
Slam latches are spring-loaded to ensure that doors lock automatically upon closing. Some feature keys, while others require only manual opening. All consist of tension loaded rollers and strike plates. Some feature a lever or trigger that must be engaged to open the latch, while others can be opened using opposing force alone. This common form of latch can often be found in commercial refrigerators.
Toggle latches are comprised of pivoting levers and drawbars. They're typically found in cabinets, toolboxes, and other light-duty applications. To engage a toggle latch, users need only pull the lever arm down to move the drawbar, allowing the door to close and latch. A similar form of latch is also used on trucks to secure hoods.
Cam latches consist of bases and cam levers that are engaged via twisting. Like toggle latches, they're most often found on cabinet doors. Unlike toggle latches, they rely on the cam's rotation within its base to keep the door tightly shut. Cam latches often feature locks.
Hook latches are specialized spring-loaded devices designed to prevent loaded lines from jumping hooks. They're used almost exclusively in lifting applications.
Gravity latches are most commonly used as gate latch hardware. They consist of a latch arm and a strike plate and rely on the force of the swinging gate to push the latch arm into the strike plate's catch. From the other side of the gate, users must lift the latch arm manually to open it.
How to Choose the Right Latch
Before choosing a latch type, consider the intended application and its mechanical requirements. Some latches feature locks, while others do not. Gravity latches can be opened from either side, while other types must be opened manually from the same side. There are also multiple materials, mounting types, sizes, and styles available. When in doubt, ask a specialist.