Terminology (Glossary)

A number of terms, expressions and their definitions will be welcomed by the uninitiated, and as space forbids the inclusion of all the names this nomenclature has been adapted to those used in this book: Return to Table of Contents
The Banker's Key:
Used by the custodian to operate one of the locks of a safe-deposit box in the case of a renter's and custodian's control lock.

Bank Lock:
A term for high security locks for safes and strongrooms in banks.

The blade or beard projecting from the stem or shank, with the bits and notches, which serves to raise the levers when the key is turned. The number of bits and notches, also called steps, corresponds with the number of levers.

Sliding piece of locks, shooting out of the lock case to fit into a socket or staple on the door frame (see latch and dead bolt).

The exterior part of a lock in which the mechanisms and action are built.

Change Key Lock:
Operated by any key chosen from a large number of different keys. The selected key is used to throw out the bolt and after that is the only key which will next withdraw it. Changes can be made as often as desired, in excess of one million.

Combination Lock:
One which is operated by a rotating dial by which certain numbers or letters in a particular order, after a given number of turns in the prescribed direction, are brought opposite the setting mark, after which the lock can be opened.

Dial of Combination Lock:
See Combination lock.

Control Key:
Used to re-adjust a combination lock.

Corrugated Key:
One of sheet metal in which corrugations are pressed or milled in the bit or shank, as used with cylinder locks.

The part of a cylinder lock which provides the security. It consists of a short cylindrical plug containing the key hole and mechanism, adjustable by the key.

Cylinder Lock:
One having a cylinder or cylinders with pin tumbler mechanism.

Dead Bolt:
The square or round bolt which is moved both inwards and outwards by the key

Dead Latch:
A latch which can be fixed or is automatically fixed to replace a dead bolt.

Dial Lock:
See Combination lock.

Double Bitted Key:
One with a bit on each side of the shank, with steps, to raise the levers.

Double Throw Lock:
One with a bolt which, after the first throw, can be shot out further by an extra turn of the key, and requires two turns to withdraw it fully.

Drill Pin:
A fixed stump or pin in a lock on which a pipe key fits to rotate.

A frontispiece of a lock covering the keyhole.

Espagnolette Bolt:
A door or window fastening having bolts the full height of the door or window which are centrally operated by a central handle or a key.

Flat Key:
One that is made from strip metal and remains flat without groove or corrugation.

Flush Bolt:
A door bolt which can be recessed flush into the edge of a door.

Flush Lock:
A flush fitting lock.

Folding Key:
A key of which the two halves are hinged together and can be folded to facilitate carrying about.

The part of the lock which is turned by handle or spindle to withdraw the latch holt.

The slot in a lever, through which the bolt stump passes during the travel of dead bolt or runner.

A fixed part inside a lock to prevent false keys from turning or to prevent an instrument from reaching the bolt or lever.

The steps in the beard of a key which serve to raise the levers in opening position.

Letter Lock:
See Combination lock.

A flat piece of modelled sheet metal of which one or more in a lock must be lifted simultaneously but differently by the various steps of the key to block the dead bolt either in open or locked position.

Lever Belly:
The lower curved edge of the lever which the key touches and slides.

Lever Handle:
An alternative to a knob; to be pressed down for withdrawing a spring bolt.

Lever Handle Lock:
The lock of which the bolt is withdrawn by turning downwards spindle or handle.

Lock Cover:
Is screwed to the lock plate to cover the moving parts and to keep them in place.

Lock Pick (or picking tool):
An instrument of high precision made for the purpose of opening locks when the key is not available. Lock pick is also the name sometimes given to a person who opens the locks in this manner.

Lock Plate:
The plate of a lock in which all the pins, studs and stumps are riveted and to which the front plate is fixed.

Master Key:
The key which passes a number of different locks.

Mortice Locks:
A lock which is inserted into a hole cut in the style of the door.

Interchangeable Lock:
A lock (for safe deposit boxes) interchangeable from one door to another by control of the renter's key.

Key Exchangeable Lock:
A key lock (for safe deposit boxes) operated by several keys but which only opens by turning the key, to the steps of which it has been adjusted.

Key Hole:
The opening by which the key is put into the lock.

Key Way:
The longitudinal cut in a cylinder lock plug to receive the corrugated key.

The round or otherwise balanced handle attached to a lock, latch, door or piece of furniture, which may be gripped for turning or pulling.

Knob Latch:
The name used instead of lock for the type having a spring bolt withdrawn by a knob only but no key.

Knob Lock:
A lock having a spring bolt withdrawn by a knob and a dead one moved inwards or outwards by a key.

Knob Handle Lock:
The latch bolt of this type of lock is moved inwards or outwards by a spindle, which can be turned either. to right or left.

Another name for the type of lock having bevelled spring bolt which is self acting when closing a door.

Latch Bolt:
Another name for spring bolt. It is a bevelled bolt, pushed into the lock case when closing a door.

Night Latch:
A spring bolt lock which can be operated by a key from the outside only and a knob from inside.

A detachable lock of which the swinging shackle passes through a hasp and staple or something similar.

Paracentric Key:
A cylinder lock key with the usual corrugations on one or both sides which reach or nearly reach the centre of the thickness of the bit, thus preventing a flat strip, like a blade of a knife, from entering the keyhole.

Variation in the order, size and form of the incisions or steps in a key bit.

Pin Tumblers:
The name of the pins to provide security in a cylinder lock, of which the upper are known separately as rollers and the lower ones as pins.

Pipe Key:
One with a flat bit and a circular shank drilled to fit on the drill pin. AKA "drill key" in the U.S.

Renter's Key:
A key supplied by the bank to the renter of a particular safe deposit lock and which moves the lock of the client under the control of the custodian's or bank employee's key.

Rim Lock:
One which is fixed on the inner face of the door style.

Safe Deposit Lock:
One for the door of a locker which a person may rent at a safe deposit. The lock, usually with two keyholes, provides dual control requiring the custodian of the bank to use a key to release the mechanism before the renter, with another key, can withdraw the bolt of the lock and open the door. (See also: Renter's Key).

Servant Key:
A key peculiar to a particular lock in a master keyed suite.

Key Shank:
The part of the key between the bow and the bit.

Single Throw Lock:
One with a bolt which is shot out by one turn of the key only.

Skeleton Key:
A key with a bit which is cut away as much as possible to avoid obstructions in a lock, but with enough left on the bit to lift the tumbler and move the bolt.

A small sliding flat piece with notches lifted by a key (e.g. the Bramah key) to move the bolt. A slider usually means a sliding lever.

The shaft of a knob or handle usually square in section which passes through the follower to enable the handle, when turned, to operate the spring holt.

Stem of the Key or Key Shank:
That part of the key between the bow and the bit.

Strike (Strike Plate):
The metal plate fixed to a door style into which the spring bolt of a lock and the dead bolt, if there is one, shoots. This plate is provided with a lip on which the spring bolt strikes.

A pin (square or round) used in the case of a lock to guide the different parts. Sometimes it serves to receive a screw and is used in lever locks to work in the gatings.

Sub Master Key:
When locks are divided into two or more different groups or suites the key which passes some of the different locks in one suite is called a sub master key and the key which controls all the suites a grand master key (See also: Master Key).

The notch or grab in a dead bolt or runner which the key enters to operate the dead bolt or runner.

A part to retain the bolt or provide security in certain locks. This word is mostly used in the U.S.A. for the English word 'lever".

A fixed projection in a lock to prevent a key from entering or turning unless suitably shapped.

Warded Key:
A key where the bit has been cut away or notched to allow wards in the lock to pass through the bit, as it turns to operate the levers or bolt.

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