To provide secure locking of swinging cell doors using third party access control systems or conventional key control where automatic deadlocking is a requirement.


The 4L79 is a surface mounted lock of robust construction based on the Chubb Lock Custodial Services standard cell lock footprint.

The main bolt is a automatically extended providing a throw of 32mm and deadlocked on closure of door:

Electrical Mode. Deadlocking is achieved when the door is closed and the bolt fully extended, no electric input is required to lock. Unlocking by 24 volt DC from an external source to energise (lift) the locking solenoid and withdrawing the bolt via the handle. The bolt remains retracted when fully withdrawn and out of frame. Solenoid is designed to be momentarily energised to facilitate unlocking. 

Mechanical Locking. Locking achieved using conventional (mechanical) key to engage a secondary deadlock when the door is in frame and main bolt is fully extended. Electric unlocking cannot be achieved while the mechanical locking mechanism is engaged.

Manual Override. In the event of power or communication failure an override key is used to lift (override) the electric locking unit. 

Both keys are supplied to a different combination and are clearly identified. 


Solid Case Technology; Lock case machined from single piece carbon steel.
Steel main bolt, with carbide anti-cutting rollers, and 32mm throw.
Unique solenoid electric locking latch.
Independent 7-lever locking mechanism.
Factory restricted key section.
Lock provides status monitoring of critical functions and tamper.
5 bolt secure fixing.
Integral baffle arrangements to resist manipulation and interference via the keyhole.


Mechanical locking mechanism tested to a minimum of 100,000 operations.
Handle mechanism tested to a minimum of 300,000 bolt operations.
Solenoid locking unit tested to a minimum of 1,000,000 cycles.
Solenoid arrangement designed to operate at +/-10% of 24V DC regulated supply.
Nominal operating current 250mA.
Saw attack 12 hours.
End load 13.5 KN.
Side Load 25 KN.

Additional features

Anti-ligature handle and escutcheon design.
Range of fixings including backplates, stud fixings, locking plate and keeps.
Interchangeable mechanical inner locking unit to enable re-coding.
Door cable available in 3m or 10m lengths (not supplied with lock).
This lock is not available under a master key system.

Materials and finishes

Lock case - carbon steel electro-plated and powder coated exterior. 
Main bolt - carbon steel electro-plated.
Main bolt follower high tensile brass.
Keys – Hardened Steel.
Levers and springs – Brass / phosphor Bronze.

Dimensions and Weights

Case Height 286mm
Case Length 267mm
Case Thickness 29mm
Bolt Throw 32mm
Bolt Depth 45mm
Bolt Thickness 22mm

Weight (lock only) 12.4Kg

TOTAL RANGE The lock is available in left or right hand
variants for opening in or opening out doors and can be
fitted to steel or wooden doors.

Fully dimensioned customer drawings are available

on request to assist with door preparation.