Coffin Lock is a slang term for a blind panel connector (also called a Butt-Joint Fastener) often used in the performing arts

Performing arts

The performing arts are those forms art which differ from the plastic arts insofar as the former uses the artist's own body, face, and presence as a medium, and the latter uses materials such as clay, metal or paint which can be molded or transformed to create some physical art object...

 to join together stage decks or scenery in a butt joint

Butt joint

A butt joint is a joinery technique in which two members are joined by simply butting them together. The butt joint is the simplest joint to make since it merely involves cutting the members to the appropriate length and butting them together. It is also the weakest because unless some form of...

 or cabinet and lid locks on road cases. These are typically two part connectors (male and female) that draw together and lock. The two most common types are the cam

Cam

A cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...

 and acceptor (sold under the trade name "Roto-Lock") and more traditional hook and pin version. These devices generally use an Allen key

Hex key

A hex key, Allen key, or Allen wrench is a tool of hexagonal cross-section used to drive bolts and screws that have a hexagonal socket in the head .- Nomenclature :...

 to operate the locking mechanism via a small diameter hole either through the face or rear of the panel. When locked, the considerable mechanical advantage

Mechanical advantage

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Ideally, the device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force...

 offered by the cam or hook holds the panels tightly together. Coffin locks can be installed directly into a mortise

Mortise

Mortise or mortice may refer to:* Mortise and tenon, a woodworking joint* Ankle mortise, part of the distal tibia joining the talus bone to form an ankle joint* Mortise chisel, a type of chisel* Mortice lock - a deadlocking lock....

cut into each panel for total concealment except for the locking hole or mounted to the rear of the panels.

Many small theatres use stock platforms with Coffin locks built in to the frames. In this case it is important to pay attention when installing platforms that they are oriented correctly, such that all of the locks can mate. These theatres will typically keep a T-handled hex key as it is easier and faster to use than a traditional L-shaped Allen wrench.