day gate

n. a barrier used to restrict passage during normal business hours, normally used at a vault entrance

day key

n. 1. the key for a day gate or day operation of a safe or vault lock 2. a cash register key which does not allow audit or reset functions 3. see 'change key'

daylock

1. n. a locking device, other than the primary lock, used to maintain the safe in a locked condition, 2. v. to insecurely close a safe or vault door without scrambling the combination, even though the door may not be opened by simply turning or pulling the handle

dead pin

n. an immovable pin in a tubular lock which functions as a ward

deadbolt

n. a bolt, which requires a deliberate action to extend, and which resists end pressure in the unlocking direction when fully extended

deadlock

n. a lock which incorporates a deadbolt

deadlocking

adj. pertaining to any feature which, when fully engaged, resists attempts to move the latch or bolt in the unlocking direction through direct pressure

deadlocking latch

n. a latchbolt with a deadlocking mechanism

declining step key

n. a key whose cuts are equal or deeper as you proceed from bow to tip

deco key finish

n. any design embossed or imprinted on a key to give it an aesthetic appearance 

decode

v. to determine a key combination by physical measurement of a key and/or cylinder parts

decoder gauge

n. a measuring device which helps determine the combination of a lock or cylinder without removing the tumblers

deflector cover

n. a removable shield designed to prevent pin point drilling on a safe

degree of rotation

n. a specification for the angle at which a cut is made into a key blade as referenced from the perpendicular; e.g., right (R or 2), left (L or 1) or center (= perpendicular) (C). This specification is typically used for some high security keys.

delamination

v. the process on older laminated door safes of having to remove some layers of the lamination to allow access to the lock

delayed action timer

n. a secondary device which prevents movement of a bolt or boltworks until a set amount of time has elapsed. The device is normally set or activated as part of the unlocking process.

delayed egress

n. an exit that will not open until a preset amount of time after actuation has elapsed

department master key

n. a master key which operates all or most master keyed locks of a given department

depth key set

n. a set of keys used to make a code original key on a key duplicating machine to a lock manufacturer's given set of key bitting specifications. Each key is cut with the correct spacing to one depth only in all bitting positions, with one key for each depth.

derived series

n. a series of blind codes and bittings which are directly related to those of another bitting list

detector lever

n. a lever tumbler with an extra gate that, when elevated beyond the bolt fence, accepts a latching fence to prevent further movement of the tumbler

detector lock

n. a lock that incorporates a detector lever in its mechanism

detention lock

n. a lock designed for securing a cell or other area in a prison or jail

DHI

abb. Door and Hardware Institute

dial

1. n. the typically rotatable member of a combination lock that may be used to differentiate locations on the combination wheels and cause operation of the lock, 2. v. the act of turning or rotating a dial

dial insert lock

n. a key operated cylinder used to lock the dial on a combination lock

dial ring

n. an escutcheon for a combination lock dial

dialer

n. 1. a device, which automatically places a telephone call to a pre-set number when, activated 2. an electro-mechanical device which systematically tries different combinations on a dial operated combination lock

diamond back

adj. pertaining to a rim cabinet lock whose mounting flanges and case forms the general shape of a diamond

diamond pick

n. a tumbler manipulation device with a triangular protrusion at its tip

digital dial

n. a rotatable dial that causes a separate readable index, (typically digital), to change

digital dialer

n. a telephone communication device that dials a programmed telephone number, and transmits, via tones or pulses, one or more signals to a digital receiver

dimple

n. a key cut in a dimple key

dimple key

n. a key whose cuts are drilled or milled into its blade surfaces. The cuts normally do not change the blade silhouette.

direct code

n. a designation assigned to a particular key which includes the actual combination of the key

direct drive

adj. of or pertaining to a combination lock with the drive cam mounted on the dial's spindle shaft

direction of rotation

n. the direction a combination lock dial is to be turned when the combination is worked. It usually is specified as clockwise (CW) or right (R), or counter clockwise (CCW) or left (L).

disc tumbler

n. 1. a flat tumbler which must be drawn into the cylinder plug by the proper key so that none of its extremities extends into the shell 2. a flat, usually rectangular tumbler with a gate which must be aligned with a sidebar by the proper key

diskette lock

n. a usually key operated device which blocks access to the drive for a removable disk

display key

n. a special change key in a hotel master key system which will allow access to one designated guest room, even if the lock is in the shut out mode. It may also act as a shut out key for that room.

divided plug keyway

n. a cylinder plug divided at the keyway into two parts. Either part may be replaced to result in a different keyway combination via different warding for the keyway

dog

1. v. to place an exit device in the holdback mode 2. n. in marine applications the latch for a hatch

dogging cylinder

n. a key operated cylinder used to dog an exit device

dogging device

n. in an exit device, a mechanism used to temporarily disable the latch from locking

dogging key

n. a key or tool used to dog an exit device

dogging screw

n. a screw used to dog an exit device

door bumper

n. an obstruction installed to prevent a door or lock from contacting another object

door closer

n. a device designed to regulate the closing of a door automatically by various means

door control

n. any device which controls the opening, closing or position of a door

door holder

n. any device designed to maintain a door in the open position

door lug

n. a non-movable projection on a safe door that helps keep the door in the locked position

door puller

n. a tool designed to open a safe deposit box by forcibly pulling the door and breaking the lock

door silencer

n. a bumper installed in the jamb stop to quiet the closing of a door

door swing

adj. the direction and degree to which a door opens, as LH 90º, RH 180º, etc.

door viewer

n. a device with one or more lenses, mounted in a door at eye level, which allows a limited view through a door

double-acting closer

n. a door closer designed to be used on a double-acting door

double- acting door

adj. a door that may be pushed open from either side

double-acting hinge

n. a hinge which permits movement of a door in either direction from the closed position

double-acting lever tumbler

n. one that must be lifted a precise amount, neither too little nor too much to allow movement of a bolt

double bitted key

n. a key typically bitted on two opposite surfaces

double cut

1. n. two bittings for the same tumbler position 2. adj. see "double bitted key"

double cylinder

adj. pertaining to a lock with two keyed cylinders

double cylinder deadlock

n. a deadbolt lock whose bolt may be operated by a key from either side

double-D

n . a shape consisting of two opposing arcs and two opposing flats adj. 2. Having such a shape.

double-D punch

n. a tool used to make a double-D hole

double horn

adj. of or pertaining to a safe deposit type lock which requires two separate holes through the door

double locking

adj. of or pertaining to a lock with one or more bolts with different functions, typically a latch and a deadbolt

double pin

v. o place more than one master pin in a single pin chamber

double throw bolt

n. a deadbolt that has two distinct extended positions, both of which are deadlocked

drawback latch/lock

n. a latch/lock whose latch is disengaged by pushing or pulling an actuator toward the hinge side of the jamb

draw sheet

n. a page with a completed matrix of potential combinations used in Matrix Format Master Keying

drill point

n. the exact measurement of the location used to drill a locked up container to effect an opening

drive cam

n. the first wheel rotated by a dial or key that has an opening designed to allow the fence, lever, or tailbar to enter and facilitate in opening of the lock or safe

drive-in

adj. pertaining to a latch or bolt with a round face

driver spring

n. a spring placed on top of the pin stack to exert pressure on the pin tumblers

drop

n. a pivoting or swinging dust cover, see also "increment"

drop bolt

n. a lock with an interlocking bolt which moves vertically and may enter loops on the strike

drop in

n. the gate area of the drive cam where the lever nose drops into. Usually identified with a corresponding number on the dial

drop-in point

n. the location in a combination lock where the wheel gates are aligned with the fence

drop ring

n. a looped handle which can pivot, typically recessed and falls flush with the door face when not in use

dual custody

n. 1. a function designed to require the presence of two persons with two different keys, combinations or codes to operate the same device 2. adj. Pertaining to such a function

dual locking cylinder

n. a style of lock cylinder whose key operates two independent locking mechanisms within the cylinder

dumbbell pin

n. a spool pin with serrations at the larger diameter ends

dumb card

n. an authorization credential that presents recorded data only

dumb reader

n. an access control interrogation device that can only relay data to a controller

dummy

adj. pertaining to any type of non-active device applied for aesthetic purposes

dummy cylinder

n. a non-functional facsimile of a rim or mortise cylinder used for appearance only, usually to conceal a cylinder hole

dummy trim

n. non-active trim applied for aesthetic purposes

duplex

n. an early trade name used by Yale for locks which offer the functionality of master keying by incorporating two cylinders on the same side of the door, or two keyways in a lever tumbler lock. One keyway is for the change key and the other keyway is for the 'master key'.

duplicate

v. to copy, see also "duplicate key"

duplicate key

n. any key reproduced from a pattern key

duress code

n. a special combination or operation sequence which conveys an alarm or other signal to a remote location while allowing access

dust box

n. an enclosure applied under a strike to enhance appearance and/or performance

dust cover

n. a device designed to prevent foreign matter from entering a mechanism through the keyway

dustproof cylinder

n. a cylinder designed to prevent foreign matter from entering either end of the keyway

dust proof strike

n. a typically floor mounted strike that has a spring loaded internal plunger designed to keep the receptacle free of dust and debris

Dutch door bolt

n. a bolt which secures the top section of a Dutch door to the bottom section

Source: Lock Industry Standards and Training (LIST) Council