door repair

UPVC Mechanism Repairs

What is a Lock Mechanism?

A lock mechanism is the collection of parts within a lock that, once assembled, allows it to work. In the majority of common locks, the lock mechanism holds or manoeuvres a latch, bolt, or shackle to the unlocked or locked position. Because there are so many types of lock types and designs, there are a great number of different types of locking mechanisms.

For example, a door lock houses a lock mechanism to move a latch or bolt. The latch or bolt is the part that extends into the strike, securing the door to the door frame. When the bolt is thrown, it moves into the strike and locks the door; when the bolt is released back out of the strike, the door is free to open.

In comparison, a padlock contains a mechanism that holds the shackle in the case or shell of the lock, or that allows the shackle to release.

Locks compared to Lock Mechanisms

It’s a good idea to know the difference between a lock and a lock mechanism. The word ‘lock’ is a common term that refers to any device fitted or attached to create better security. A padlock, a door lock, a car ignition lock—all of these are locks. A lock mechanism is the structure within a lock. I.E., a door lock may contain a pin tumbler mechanism, warded lock mechanism, or a disk tumbler mechanism, depending on how it was manufactured.

All lock mechanisms can be grouped into three basic types:

  • combination lock mechanisms
  • key-operated lock mechanisms
  • electric lock mechanisms

UPVC Door Repairs Leeds
UPVC Door Repairs Selby

Call us now on 0800 311 8152

Call us now on


Expert Locksmith


All Work Guaranteed


Residential & Commercial


Thousands of Happy Customers

Want us to call you?

    Key Lock Mechanisms

    A key lock mechanism is essentially a type of lock that opens and shuts by pushing in a key and turning it. However, keyed locks are the most used and recognised. Key locks are found in many types of situations, including: residential doors, cars and padlocks.

    The 4 most used types of key operated lock mechanisms are the disk tumbler or wafer mechanism, the warded mechanism, the lever tumbler mechanism and the pin tumbler mechanism.

    Combination Lock Mechanisms

    This type of lock mechanism does not use a key and is called a combination lock mechanism. Combination lock mechanisms tend to be used in locks such as padlocks, safes, door entry systems and vaults. Combination locks differ in how they are built, with variations depending on make and model, however, they all work in the same way.

    Combination locks have a near infinite number of uses, such as school lockers to safes to trailer hitches. They have clear advantages over key locks in situations where multiple people need access to the same equipment at random times. In a production plant, for example, six or eight workers may need to share tools or supplies that are too valuable to be left out in the open. Rather than provide each person with a key (which could be lost or stolen, requiring immediate rekeying or lock replacement), each can be given a simple digit combination.

    Electric Lock Mechanisms

    Electric locks are used widely by many types of businesses, hospitals, and industries. These keyless locks can be used on rear or side entries of a business to allow employees to enter and exit the building. Some homes and apartments have key-less entry systems to eliminate the need for keys.

    Most modern hotels use electric locks for entry doors and/or keyless electric locks for the actual room doors. In addition, many of the hotel’s interior doors may be held open using electric locks. Then, if a fire is sensed by the alarm system, these doors close to prevent the fire from spreading.

    • A lock mechanism is the assembly of parts inside a lock that makes it work. All lock mechanisms can be divided into three basic types: key-operated lock mechanisms, combination lock mechanisms, and electric lock mechanisms. A key-operated lock mechanism is simply any type of lock that’s opened and closed by inserting and turning a key. Key-operated locks are found in residential doors, cars, and padlocks.
    • The warded lock mechanism is the oldest type still in use today. Bit keys and barrel keys are used to open warded door and cabinet locks. The word ward means to guard or guard against. In locksmith terms, a ward is a metal barrier inside a lock mechanism that ensures that only the proper key will engage the mechanism and open the lock. The “right” key contains cuts that exactly match the shape of the wards inside the lock.
    • Warded locks aren’t generally used on today’s exterior doors. They have been replaced by pin tumbler or disk tumbler locks in most cases. This is because warded locks aren’t nearly as secure as pin tumbler locks since the warded lock has a simple mechanism and the keyhole is large enough to view most of the lock’s inside.
    • Lever tumbler lock mechanisms are used on school lockers, cash boxes, suitcases, mailboxes, and safe-deposit boxes. The slim, flat design of the lever lock is more appropriate for these applications than a cylinder-type lock. Modern lever tumbler locks almost always use flat keys.
    • The lever tumbler mechanism may contain from one to six-teen lever tumblers, depending on the security of the lock. Each lever tumbler is a flat metal plate held in place by spring pressure. When the key is inserted, the lever tumblers are lifted and aligned inside the lock, allowing the lock to open.
    • The disk tumbler mechanism (also called the wafer tumbler mechanism) is commonly used in automobile doors, desks and cabinets, and vending machines. The main components of a disk tumbler lock are the shell, the plug, the disks, and the springs. The disks or wafers are small, flat, rectangular pieces of steel, each containing a slot or hole. For most disk locks, the disks come in five different slot arrangements. The location of the slot in each disk will determine the key cut depth needed.
    • A disk tumbler lock’s plug will contain an arrangement of any of these five disks (any one of the disks may appear more than once, as well). The arrangement of the disks forms each lock’s individual combination. The disks are slotted for key entry. When the proper key is inserted into the lock, the disks are pulled away from the lock shell and centred in the plug. This action frees the plug from the shell and allows the plug to turn with the key.
    • Another variation of the disk tumbler mechanism is the cam lock. Cam locks are used extensively on cabinet doors and desk drawers. In this kind of lock, a movable cam is attached to the rear of the lock. The cam rotates when the key is turned in the lock, creating a physical barrier that prevents a door or drawer from being pulled open.
    • The pin tumbler lock is the most secure and widely used lock today. This type of lock is very popular in home entry locks, padlocks, and other types of locking devices. Pin tumbler lock mechanisms are always operated with cylinder keys. The pin tumbler mechanism is relatively easy to disassemble and repair.
    • A pin tumbler mechanism is contained within a device called a cylinder. A pin tumbler cylinder holds the plug, which is a small “tube” containing the bottom pins. The heights of the bottom pins correspond to the cut depths in the key. The top pins are all the same height and rest halfway between the plug and the cylinder, preventing the plug from rotating inside the cylinder.
    • When the proper key is inserted in the lock, the pins are lifted to the height necessary to align them along the shear line, freeing the plug to turn. By changing the heights and placement of pins in the lock plug, the locksmith can make a different key to operate the lock. This process is called rekeying.
    • High-security locks are locking devices that are especially resistant to picking and forced entry. Most high-security locks contain complex or modified pin tumbler mechanisms. For example, some high-security mechanisms hold more than one set of pins. The pins enter the lock cylinder at an angle, and the key must be specially cut to accept the pins at that angle. Some other features manufacturers add to their high-security mechanisms are sidebars, split keys, multiple locking mechanisms, anti-wrenching pins, and high-security strikes.
    • Interchangeable or removable cores are specially-designed lock cylinders that can be removed from a door lockset without disassembling the lock or doorknob. To remove the core, a special key called a control key is inserted and turned, and the core is then withdrawn. Most of these locks are used in commercial installations.
    • Padlocks are another common type of key-operated lock. Remember that the main parts of a padlock are the shackle, the shell, and the tangs. The shackle is held in two locations by the locking mechanism near the top of the lock. The two tangs at the top of the plug, when rotated, cause the locking mechanism to retract. This action causes the shackle to raise under spring pressure. No key is required to lock the padlock. Finger pressure is sufficient to return the shackle to the case, where the bolts catch the notch and secure it.
    • Another type of key-operated padlock is the warded padlock. A warded padlock is constructed from many flat layers of metal. The flat layers are then stacked up and laminated together to form the body of the lock. Small cuts are made in some of the layers to create wards in the lock body. When all the layers are stacked up, the key will need to be cut to correspond to the lock’s wards.
    • A commercial lubricant such as WD-40 (never oil) should be used to lubricate lock parts.
    • Combination lock mechanisms are used in many types of padlocks, door entry systems, safes, and vaults. The combination is a series of numbers that are dialled to open the lock. The dial is a numbered knob on the outside of the lock which is used to dial the combination. The dial is turned clockwise and counter-clockwise to reach the numbers in the combination. As the dial is turned, the wheels inside are aligned. Each time a correct number from the combination is dialled, another wheel clicks into place. When all the numbers have been dialled, the wheels will be completely aligned, freeing the lock to open.
    • The pushbutton combination lock is a popular type of combination entry lock that is especially common in hotels or other facilities where many strangers come and go at will. Instead of having to supply each person with a key, a three-number combination is supplied. The combination can be changed quickly and easily to maintain security.
    • Electric locks are used by many types of businesses, hospitals, and industries. In the simplest electric lock circuit, a single switch or pushbutton and an electric lock is used to protect one door. The power supply for this electric lock consists of a fuse and a transformer. When a pushbutton is pressed, the circuit is completed and the coil is energised. When the coil is energized, the coil attracts a plunger that allows the door to open