Glossary of terms

Anti-Friction Latch Bolt

The latch bolt of a lock equipped with a device for reducing friction between bolt and strike. Usually a small trigger attached to the bolt contacts the strike and exerts a lever action to depress the bolt.

Auxiliary Bolt

An additional bolt which is activated by the strike when the door is closed, automatically dead latching the latch bolt against end pressure.

Awning Window

A window with an outward opening sash, hung about a horizontal axis at the top or on friction stays at the sides.

Backcheck

The feature of a door closer unit that prevents shock and possible damage when the door is forcibly opened.

Backset

The horizontal distance from the face of the lock to the centre line of the cylinder, key hole or knob hub.

Barrel

A cylindrical portion of the cylinder that rotates when the correct key is used.

Bi-fold

A sliding door or window with sections that fold onto one another as the door opens.

Box Strike

A strike in which the latch bolt recess is enclosed or boxed, thus covering the opening in the jamb.

Cam

A lever attached to the end of a barrel to activate the lock mechanism.

Casement Window

A window with a sash hung about a vertical axis by hinges at the side.

Construction Key

A key supplied with construction keyed locks. During construction, a builder gains entry using the construction key. On completion of the building, action is taken to render the construction key inoperative, preventing further entry by the builder.

Construction Keying

System used to allow contractors to gain entry to a building during construction but to prevent entry by the same contractors after the building has been occupied or handed over.

Cylinder

The assembly incorporating the key operated mechanism.

Dead latch

A lock containing a dead latch bolt.

Deadbolt

A bolt which is not activated by a spring. When locked the bolt cannot be returned by end pressure.

Deadlatch Bolt

A spring actuated bevelled latch bolt which operates in conjunction with an auxiliary bolt which automatically locks the latch bolt against return by end pressure.

Deadlock

A lock incorporating a deadbolt.

Deadlocking Latch

A lock with a spring-actuated latch bolt. When the door is closed, the key or turn knob is operated to deadlock the latch bolt against return by end pressure.

Delayed Action

A feature of a door closer which holds the door in the open position for a number of seconds before the closing action commences. This feature is ideal for use by the handicapped, the aged and people with prams, trolleys, etc. The SAA Fire Door code approves the use of delayed action closers on fire doors.

Disc Tumblers

Flat discs or wafers which are spring loaded to prevent the cylinder plug from rotating until the correct key is inserted.

Double Hung Sash Window

A window with two sashes which slides vertically in a window frame.

Dummy Trim

A non-operating door trim which is installed for appearance or as a door pull only.

Electric Strikes or Door Opener

An electrical device that replaces a regular lock strike to enable a door to be released by remote control.

Finish

Final cover treatment of the product for appearance and protection, in both plated finishes or powder coat colour.

Furniture

Fittings complimentary to the lock systems, such as handles and escutcheon plates.

Grand Master Key

A key which will operate two or more groups of locks, where each group can be operated by individual master keys and locks within each group can be operated by different service keys.

Handed Products

A product designed or assembled for use only on right hand doors or only left hand doors, but not both.

Handing

The direction of door travel (swinging or sliding) and the locking/secure side of a door, eg. Right hand (opening out), left hand (opening out). click here for more infomation

Hold-back

A catch or other device on a lock which can hold the latch bolt in the retracted position.

Hold-open

The feature of a door closer unit which enables a door to be held in the opened position until released.

Indicator Bolt

A slide-action bolt installed in areas where privacy is desired (such as toilets and bathrooms) which provides visual indication that the room is occupied or vacant.

Jamb

Vertical posts or pieces that together form the sides of a door or window frame.

Keyed Alike

Indicates identical key for 2 or more locks.

Keyed to Differ

A different key is needed to activate each lock. 

Latch

The fastening on a door that fits into the notch or slot on a door jamb and is lifted from either side by the handle.

Latch bolt

A spring actuated, bevelled bolt usually operated by door furniture.

Lockset

A lock, complete with strike and door furniture, such as knobs, levers, escutcheons, or handles.

Maison System

A keying system suitable for apartments, flats, offices, hotels and motels. Each apartment, flat or office has its own key which will not operate the locks to another apartment, flat or office but will, however, operate the locks to communal entrances and service areas.

Master Key

A key which will operate a group of locks, each built to operate on a different service key.

Mortice

An opening made to receive a lock or other hardware. Also the act of making such an opening.

Mortice Lock


A lock designed to be recessed into the edge of a door, rather than being mounted to its surface.

Negative Pressure

A pressure imbalance between the inside and outside of a window/door resulting in a force tending to pull the window/door off a building.

Nightlatch

A lock with a spring-actuated latch bolt.

Non-handed

The ability to reverse the product or key component to suit left or right-hand installation.

One-Way Screw

Screws with specially shaped heads to prevent removal by conventional screwdriver.

Parallel Arm Door Closer

A type of door closer installation where the arm is mounted parallel to the door, for use where the door closer is installed on the inside of an opening out door.

Passage Set

A term commonly used to describe a latch set with handles on both sides of a door but no locking function.

Patio Lock

A lock designed with a pushbutton or turn button inside to lock the outside handle. When so locked, there is no entrance by key from outside.

Pin Tumblers

Small sliding pins in a lock cylinder which work against coil springs and prevent the cylinder plug from rotating until the correct key is inserted.

Pivoting Sash

Window sash with a sash arm assembly that enables it to be opened outward as in both casement and awning applications.

Powdercoat

Polyester-based coating for aluminium products providing a smooth colour finish.

Privacy Set

A term for locks used on bathroom and bedroom doors having an inside button or turn knob to lock the outside handle and usually an emergency function which will unlock the set from the outside.

Rebated Door

A door where the leading edge is stepped.

Rebated lock/latch

A lock which has the faceplate and strike shaped to match the rebated edge of a door, usually the meeting edges of two door leaves.

Reversible Lock

A lock with the components that can be readily adapted to enable the lock to suit door of either hand, opening in or out.

Rim Lock, Rim Latch

A lock or latch which is mounted to the surface of a door, rather than inserted into the edge of the door.

Sash

A frame in which the panes of a window or door are set.

Service Key

A key which will only operate the lock that has been built to suit that service key.

Single-Action Escape Lock

A lockset installed to a door where exit is obtained by a single action without the use of a key.

Snib

A device used to either lock or unlock the lockset.

Spindle

The drive shaft that connects the knob or lever to the latch or lock mechanism to operate the bolt.

Stay

Friction hinge – top brace and support the window sash for opening. Also known as friction hinge.

Strike

A device fixed in or on a doorjamb into which the lock or latch bolt engages when the door is closed.

Strike Box

A security component used in conjunction with the strike plate to help protect the bolt against end pressure.

Surface Mounted

The lock is mounted on the surface of the door stile.

Tubular Bolt/latch

A bolt having a tubular case.

Turn Knob

Turning mechanism that activates the door lock from the inside, a convenient locking option in place of a key.

Vestibule

A hall or lobby next to the entrance door of a dwelling and from which other doors open to various rooms.

Wafer

See Disc Tumblers.