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Glossary of Terms


Alike Change –(see "keyed alike")

Anti-drill Plate –Steel plate with sufficient hardness to resist penetration by a HSS drill bit

Anti-Pick –Feature built into locking mechanisms to prevent unauthorized access

Anti-thrust Action –Latch action in which the latch bolt, when fully thrown, resists being forced back by end pressure

Anti-thrust Bolt –Spring actuated bolt which cannot be pushed back once it has been fully thrown into a correctly positioned locking plate

Anti-thrust Slide / Snib Bolt –Component which contacts the locking plate to activate the anti-thrust bolt mechanism

Armoured Padlock/Anvil Padlock –Square brass Padlock shrouded with steel body. Cylinder key operated.

Armoured Rose –Cylinder rose with features to protect it from physical attack

Backset –Distance from the outer face of the forend (or faceplate if fitted) to the centre-line of the keyhole and/or follower

Ball Locking –A method of locking used in high security padlocks. Hardened steel ball bearings are pushed outwards to engage with round indents on the shackle

Bathroom Lock –Privacy lock with latch bolt operated by lever handle or knob from both sides, and an additional deadbolt operated by thumb slide, thumb turn etc. from inside only

Blank (of key) –Key which has not been cut

Body –The main section of a product usually containing the working mechanism

Bolt (part of lock or latch) –Moving part of a lock or latch that provides engagement between leaf and frame (see also EN 12209)

Bolt-through Fixing –Method of attachment whereby the fixing means pass right through the door, window etc.

Bolt Thrower –Component within a Mortice Lock enabling greater projection of its deadbolt through the turn of its key.

Bottom Pin / Pin –Pin of a cylinder mechanism that is located in the plug and makes contact with the key

Bow (of key) –Enlarged portion of key at end remote from blade/bit

Box Lock –Cabinet lock designed for flush fitting into the edge of a box. A specifically designed staple is fitted to the box lid forming part of the locking mechanism

BS 3621:2007 –British Standard relating to Mortice Locks also known as "Thief Resistant Lock Assembly - Key Egress". Lock mechanism maybe either 5 Lever or Cylinder. The lock is often referred to as a "Kite Marked" Mortice Lock.

BS 8621:2007 –British Standard relating to Mortice Locks also known as "Thief Resistant Lock Assembly - Keyless Egress". Lock mechanism is Cylinder operated with a Thumb Turn on the inside of a door for easy egress. The lock is often referred to as a "Kite Marked" Mortice Lock.

BS 10621: 2007 –British Standard relating to Multi-point Locks also known as "Thief Resistant Dual Mode Lock Assembly"

Budget Lock –Rim fixed lock suitable for cabinets requiring little security. Operated by a square key.

Bullet Lock –Cylinder operated lock suitable for locking Roller Shutters

Bullet Lock Housing –Surface fixed lock housing providing

Burr –Plug which closes off the outer end of an individual pin chamber in a cylinder housing

Bush & Slide –Keyhole Cover for "Old English" Padlock preventing ingress of matter.

Cabinet Lock –Generic term for a variety of locks fitted to items of furniture such as cupboards, drawers, chests, boxes etc.

Cam –Component attached to the end of a cylinder plug to transmit locking/unlocking movement

Cam Lock –Cylinder lock where the cam serves as the bolt

Case –(see "lock case")

Change (of key) –(see "differ")

Change Key –Alternative term for either "servant key" or "changing key"

Claw Bolt –Pivoting claw-shaped element of a deadbolt, which serves as an anti-separation point when locked, but which withdraws fully into the lockcase when unlocked

Claw Bolt Lock –Lock comprising at least two claw bolts moving in opposite directions

Close Shackle Padlock –Padlock with most of the shackle concealed within the body

Cupboard Lock –Cabinet lock designed for surface fitting onto a cupboard door

Cut Cupboard Lock / Cut Cabinet Lock –Cabinet lock designed for flush fitting which is cut into the edge/rear face of the door

Cycle –(see "test cycle")

Cylinder –Self-contained assembly comprising at least one cylinder mechanism and the output drive element (see also EN 1303)

Cylinder Housing –Main body of cylinder

Cylinder Key –Key for use in a cylinder lock

Cylinder Latch –Latch operated by a cylinder

Cylinder Lock –Lock comprising one or more cylinders

Cylinder Night Latch –Night latch operated by a cylinder (see also "EN 12209")

Cylinder Padlock –Padlock operated by a cylinder

Cylinder Pin Tumbler Lock –Cylinder lock with pin tumbler detaining elements

Cylinder Pull –Shaped plate for fitting under the flange of a rim cylinder to provide the means to pull the door leaf using fingers

Cylinder Rose / Cylinder Ring –Substantial circular ring which surrounds the outer end of a cylinder at the surface of the leaf for decorative and/or security purposes

Dead Latch –(see "deadlocking latch")

Deadbolt –Bolt of a lock that is moved in both locking and unlocking directions by means of a key or thumb turn

Deadbolt Projection –The amount that the bolt of a lock is moved in its locking direction by means of a key or thumb turn

Deadlock –Lock with a deadbolt only

Deadlocked –Locked in such a way that movement of the bolt towards its unlocked position is positively prevented

Deadlocking –Capable of being deadlocked

Deadlocking Latch –Latch with a bolt that can be deadlocked

Detainer –Element of a lock mechanism, similar to a lever, that makes contact with the key

Differ –Variation between lock mechanisms of similar design due to differences in the lift and/or position of the detaining elements

Differ Bit –Intermediate element resulting from pin being split for the purpose of master keying

Differ Step –Step on the key bit of a lever lock that makes direct contact with, and lifts, a particular detaining element

Distance to Pin –Specific measurement of a lock referring to the distance between the edge of the lock and its drill-pin upon which a "pipe" type key would sit.

DIN Cylinder –(see "Euro Profile cylinder")

Double Throw Lock –Lock requiring two full turns of the key to fully throw the deadbolt

Draw Back Lock –Lock in which the spring bolt is withdrawn by a sliding handle

Drawer Lock –Lock for use on a drawer

Drug Cupboard Lock –Heavy type of cupboard lock used specifically for situations where greater security is required e.g. Drugs.

Emergency Exit Device –Door locking arrangement that allows keyless egress at all times, using one simple hand movement, although this may require prior knowledge of its operation (see also EN 179 and EN 1125)

Escape Lock –Lock that allows keyless egress at all times, using one simple hand movement, without the need for prior knowledge of its operation

Escutcheon –Component which surrounds the entrance to a keyhole at the surface of the leaf, for (mainly) decorative purposes (see also EN 1906)

Euro Profile Cylinder / DIN Cylinder –Profile cylinder for which the cross-section of the housing is to the standard European profile

Faceplate / Face Plate / Outer Forend –Additional plate mounted over forend for decorative purposes

Follower –Component that transmits rotational movement from a spindle (linked to the handle/knob) to the latch bolt, to withdraw it against spring force

Forend / Fore End / Inner Forend –Long narrow plate attached to, but extending beyond, the lockcase, for mounting purposes (see also EN 12209)

Galvanised Padlock –Term sometimes used to describe an "Old English" Padlock referring to its appearance

Grand Master Key –Key that operates locks of all combinations in a suite, including those in lower level suites under separate submaster keys

Handed –Restricted to one particular closing direction only (either clockwise closing only or anti-clockwise closing only)

Handing –Property relating to the direction a leaf rotates to close

Hardening –Heat treatment of lock components used to increase security against attack e.g. drilling

Hasp/Staple –A hinged metal strap used in conjunction with a padlock to secure doors and gates

Hook Bolt –Swing bolt in the shape of a hook

Horizontal Lock –Mortice or rim lock with the follower at the same height as the keyhole but further away from the forend

Keep / Staple –Alternative terms for "locking plate" or "striking plate" – but used, preferably, where there is no plate-like feature

Key –Instrument used to operate a lock, which can be removed and carried on the person

Key Blank –Key without steps

Key Bow –Part of the key that is held to operate it

Keyless Egress –Mechanism which allows the unlocking of a lock without a key usually by a thumb turn or handle

Key Registration –Control of key combinations to prevent unauthorized duplication of keys

Key Retention/Key Retaining –A mechanism preventing the removal of a key from a lock usually unless it is locked

Keyed Alike –Operable with the same key

Keys to Pass –(see "keyed alike")

Laminated Padlock –Padlock whose body is made up of a series of flat pieces of metal riveted together

Laminated Safe Lock –Safe lock whose body is made up of a series of flat pieces of metal riveted together

Latch –Self-engaging fastener which secures the leaf of a door or window in the closed position, and which can be released by hand

Latch Bolt –Bolt which, by virtue of its shape and the forces acting on it, engages automatically with the locking plate as the door is closed

Left Hand Door –Door which opens in a clockwise direction when viewed from above

Lever –Element of a lock mechanism, similar to a detainer, that makes contact with the key

Lever Mechanism –Lock mechanism comprising one or more levers

Lock –Device for securing a door or window in the closed position, where unlocking movement of the bolt is by means of a differ key from at least one side

Lock Case –Cylinder mortice lock without the cylinder

Locker Lock –Steel bodied surface fixing lock operated by either a lever or cylinder mechanism suitable for use on steel cabinets

Locking Plate –Generally accepted term for any component that engages the bolt or bolts of a lock (i.e. it includes striking plate, keep and staple)

Locking Snib –Hand operated device for preventing a bolt from being thrown or withdrawn, or to change the function of a lock or latch without dismantling

Magazine Lock –Very heavy brass Rim Lock specifically designed for use by military bodies (particularly naval) for security of ammunition etc.

Master Key –Key that operates locks of all combinations within a particular suite

Master Keyed Suite –Set of locks and/or padlocks related by a common key, or keys

Microswitch –Device providing indication of the

Mortice Cupboard Lock –Cabinet lock designed for mortice fitting into the edge of a cupboard door

Mortice Cylinder –Cylinder for use with a mortice lock

Mortice deadlock –Deadlock adapted for flush fitting into a mortice

Mortice Latch –Latch adapted for flush fitting into a mortice

Mortice Lock –Lock adapted for flush fitting into a mortice

Mortice Night Latch –Night latch adapted for flush fitting into a mortice

Mushroom Roller / Mushroom Driver –Top pin with undercut groove which when under-lifted allows the plug to rotate a small amount thereby frustrating attempts to pick the cylinder

Narrow Stile Lock –Mortice lock with a case depth of less that 67mm

Night Latch –Lock with automatic bolt which is withdrawn from outside by key, and from inside by handle or knob

Non-handed –Not restricted to one particular closing direction only (either clockwise closing only or anti-clockwise closing only)

Old-English Padlock –Traditional lever operated Padlock with a steel body/shackle construction

Open Shackle Padlock –Padlock in which a complete 180° hoop of shackle is exposed

Oval Profile Cylinder –Profile cylinder for which the cross-section of the housing is oval

Padlock –Detachable and portable locking device which uses a shackle to link itself to an object, or link objects together (see also EN 12320)

Panel Lock –Two-bolt upright lock for use on metal casement doors

Panic Bar –Horizontal bar of a panic exit device which is used to activate the mechanism (see also EN 1125)

Panic Bolt(s) –(see "panic exit device")

Panic Exit –Egress point on an escape route that is likely to encounter a panic situation

Panic Exit Device –Door locking arrangement that allows egress under all conditions in response to light pressure anywhere along a horizontal bar running the width of the door (see also EN 179 and EN 1125)

Panic Latch –Latch which is released by pressure anywhere along a horizontal bar running the width of the door

Pin Key –A key used to operate a lever lock which does not have a drill-pin

Pin / Pin Tumbler –Cylindrical-shaped detaining element of a cylinder mechanism that it is positioned by the key as it is inserted

Pin Tumbler Mechanism –Locking mechanism in which the principal detaining elements are a pins

Pipe Key –A key used to operate a lever lock which has a drill-pin

Plug –Rotating part of a cylinder lock containing the pins, and into which the key is inserted (see also EN 1303)

Privacy Lock –Lock that is lockable from the inside only

Profile Cylinder –Mortice cylinder with constant cross-section housing

Push-bar –Horizontal bar of a panic exit device (see also EN 1125)

Rebate –Step in a frame (or adjacent leaf) which provides the stop for the leaf

Rebated Lock –Lock adapted to mount on the rebated edge of a leaf

Reversible Bolt –Bolt for which the closing direction (clockwise or anticlockwise) can be altered without dismantling

Right Hand Door –Door which opens in an anti-clockwise direction when viewed from above

Rim Cylinder –Cylinder for use with a rim lock or latch, and which is adapted for flush (or near flush) mounting within a leaf

Rim Deadlock –Deadlock adapted for surface mounting on the face of a leaf

Rim Latch –Latch adapted for surface mounting on the face of a leaf

Rim Lock –Lock adapted for surface mounting on the face of a leaf

Rim Night Latch –Night latch adapted for surface mounting on the face of a door leaf

Roller Bolt –Latch bolt with rotating feature in the head to facilitate withdrawal of the bolt upon engagement with the striking plate

Sash Lock –Alternative term for an upright mortice lock

Scandinavian Oval –Mortice cylinder with oval cross-section housing, attached to the lockcase using bolt through fixings

Screwed Cylinder –Mortice cylinder with threaded housing

Security Cylinder –Cylinder with a high level of resistance to attack methods

Security Escutcheon –Escutcheon with a high level of resistance to attack methods

Servant Key –Key that operates one particular lock in a master keyed suite

Shackle –The 'U' shaped metal bar on a padlock which forms the lockable link to another object (or other objects) (see also EN 12320)

Shear Line –Line representing the cylindrical surface of the plug in a pin tumbler cylinder

Shutter Lock / Roller Shutter Lock –Steel surface mounted lock used to secure Roller Shutters by means of sideways movement of its bolts

Side Bar –Element of a pin tumbler cylinder that only allows the plug to rotate when all the pin tumblers are correctly positioned

Sliding Door –Door with one or more leaves which move horizontally in their own plane

Snaplock –Method of locking a padlock without the use of a key by pushing the shackle into the body

Spindle –Bar (usually of square cross-section) that transmits the rotational movement of lever handles/knobs on either or both sides of a door leaf to the follower of a latch (see also EN 1906)

Split Follower / Divided Follower –Two-part follower that enables movement from handles/knobs on opposite side of a door leaf to be transmitted independently

Spring Bolt –Latch bolt operated by a spring

Spring Shackle Padlock –Padlock with shackle that springs open when unlocked, and which closes without the use of a key

Straight Cabinet Lock/Straight Cupboard Lock –Lock adapted to lie flat on inside face of cabinet or cupboard door

Sprung –Hardware containing a spring mechanism which enables the door handle to return to the horizontal position after use

Striking Plate / Strike Plate / Striker –Component that engages and operates a latch bolt

Sub-grand Master Key –Key which will operate all locks in a one level down subsuite of a great grand master-keyed suite

Sub-master Key –Key which will operate all locks in a one level down subsuite of a grand master-keyed suite

Suited –Belonging to a master keyed suite surface mounted door closer door closer mounted on the face of the door or door frame

Thrower –Component of a lever lock mechanism that rotates with the key and engages with the bolt to move it

Thumb Turn –Small handle or knob for operation by thumb and forefinger (see also EN 1906)

Till Lock –Lock for use on a drawer

Top Pin / Driver / Roller –Pin of a cylinder mechanism that is located in the cylinder body and is acted on by a spring

2 Way Keyhole –Characteristic of a lock which allows both down-shoot and across-shoot of its deadbolt

Unsprung –Hardware that does not containing a spring mechanism to automatically return the handle to the horizontal position after use

Walsall Locks Ltd, Leamore Close, Leamore Enterprise Park, Walsall, West Midlands, WS2 7NL, UK