Glossary - D

dead latch (np)
(see "deadlocking latch")

dead lift lever (np)
lever which allows the bolt stump to move when in the "at rest" position, but which will block movement when lifted

deadbolt (n)
bolt ¹ of a lock that is moved in both locking and unlocking directions by means of a key or thumbturn (see also EN 12209, WI 33/250, EN 179 & EN 1125)

deadlock (n)
lock with a deadbolt only (see also EN 12209)

deadlocked (adj)
locked in such a way that movement of the bolt¹ towards its unlocked position is positively prevented

deadlocking (adj)
capable of being deadlocked

deadlocking latch (np)
latch with a bolt that can be deadlocked

declared minimum test opening (np)
(Product specific term - see CEN/TS 13126)

deflection recovery (np)
(Product specific term - see EN 12365)

delayed action ¹ (np)
action which allows a door to remain open for an adjustable period of time before closing at a pre-set speed

delayed action ² (np)
locking/unlocking action with lost motion to minimise the movement of the bolt throwing element

delayed closing (np)
function of a controlled closing device that allows the closing action to be delayed for an adjustable period of time before resuming controlled closing (see also EN 1154)

detainer / detaining element / tumbler (n/np/n)
part of a lock mechanism which blocks unlocking movement when in the "at rest" position, but which allows unlocking movement when positioned by a correct key. (see also EN 1303 & EN 12209)

detector zone (np)
(Product specific term - see prEN 14637)

detent (n)
arrangement of components which prevent movement until certain conditions are satisfied

device (n)
product intended for a specific purpose

differ (n)
variation between lock mechanisms of similar design due to differences in the lift and/or position of the detaining elements (see also EN 12209)

differ bit (np)
intermediate element resulting from pin ¹ being split for the purpose of master keying

differ step (np)
step on the key bit of a lever lock that makes direct contact with, and lifts, a particular detaining element

DIN cylinder (np)
(see "Euro-profile cylinder")

direct coding (np)
marking on a key that discloses the combination

disc tumbler (np)
flat plate detainer that is positioned by the key as it is inserted

disc tumbler lock (np)
lock containing a disc tumbler locking mechanism

disc tumbler mechanism (np)
locking mechanism in which the principal detaining elements are a disc tumblers

divided follower (np)
(see "split follower")

door (n)
opening member and associated frame of sufficient height to provide access for pedestrians (see also EN 179 & prEN 12650, EN 179 & EN 1125)

door bolt (np)
bolt ² for use on a door

door chain (np)
chain link device that can be used to restrict the opening of entrance doors to dwellings, for safety purposes

door closer / door closing device (np)
device that automatically returns a door leaf to its closed position

door closer power size (np)
classification level of closing moment exerted by a door closer (see also EN 1154)

door control (np)
any device that controls the speed or timing of door leaf movement

door coordinator (np)
device used on door sets where one leaf must close before the other

door coordinator size (np)
(Product specific term - see EN 1158)

door furniture (np)
items of building hardware that are attached to a door, but excluding locks and hinges (see also EN 1906)

door guard (np)
component that can be fixed across the full width of a door to prevent the leaf from opening

door handle (np)
handle for use with a door leaf

door holder (np)
manually operated device for holding a door open

door jamb (np)
vertical member of door frame

door knob (np)
knob used to open or close a door by operating a latch and/or providing a means to pull on the door leaf by hand (see also EN 1906)

door knocker (np)
device comprising a hinged component that can be struck by hand against its mounting plate to create a sound for attracting attention

door lever handle (np)
lever handle used to open or close a door by operating a latch and providing a means to pull on the door leaf by hand (see also EN 1906)

door limiter (np)
rigid arm device that can be used to restrict the opening of entrance doors to dwellings, for safety purposes

door opening force (np)
resistance to opening, measured as a force at the outer edge of the door leaf

door pull (np)
handle (usually attached under a rim cylinder) used to close a door by providing a means to pull on the door leaf by hand

door set (np)
door leaf (or leaves), frame and accompanying hardware

door stop ¹ (np)
rebate on a door frame which arrests the closing movement of a door leaf

door stop ² (np)
component attached to a wall or floor to limit the door's opening angle

door viewer (np)
optical device with wide angle lens to provide a one-way viewing facility

door width (np)
maximum width of leaf - including any rebated edges (see also EN 1154)

double acting drive (np)
(Product specific term - see prEN 12650)

double acting lever (np)
lever ¹ that detains whether over-lifted or under-lifted

double action door closer (np)
door closer for use on doors which can be opened in both directions (see also 1154)

double action lock (np)
lock that is double locking

double arm swing coordinator (np)
(Product specific term - see EN 1158)

double bitted key (np)
key with two bits

double door set (np)
assembly comprising two hinged or pivoted door leaves in a single frame (see also EN 179 & EN 1125)

double door set device (np)
(Product specific term - EN 179 and EN 1125)

double door set emergency exit device (np)
(Product specific term - see EN 179)

double door set panic exit device (np)
(Product specific term - see EN 1125)

double forend (np)
forend comprising two plates

double handed lock (np)
lock suitable for left or right hand operation, without alteration

double locking (adj)
having two distinctly separate locking actions

double shutter hinge (np)
(Product specific term - see prEN 14648)

double throw lock (np)
lock requiring two full turns of the key to fully throw the deadbolt

draw back lock (np)
lock in which the spring bolt is withdrawn by a sliding handle

drawer handle (np)
handle which may be gripped by several fingers inserted from either side

drawer lock / till lock (np)
lock for use on a drawer

drawer pull (np)
partly enclosed projecting handle into which only the ends of the fingers may be inserted (Picture required)

drill pin (np)
short rod fixed opposite the keyhole in a lockcase to provide the location and bearing for a pipe key

drill resistant (np)
comprising features to limit the effectiveness of drill attack

drilled through spindle (np)
spindle with transverse holes at each end for attaching handles or knobs

drive (n)
(Product specific term - see prEN 12650)

driver (n)
(see "top pin")

drop ¹ (n)
keyhole cover for a padlock

drop ² (n)
distance from selvage to centre line of keyhole on drawer and box locks

drop bolt (np)
bolt ² at bottom of door which falls under gravity into floor socket as door is closed

drop handle (np)
pivoting handle that falls by gravity to vertical position when not in use

DT pillar/DT stump/DT spindle (np)
short drilled and tapped rod fixed inside lock case to help control internal height and provide means for fixing the cap

dummy cut through (np)
(see "cut through")