A concealed hinge, also known as a hidden or European hinge, is a type of hinge that has parts invisible to the onlooker when the door is closed. They are commonly used in cabinet doors to add an aesthetically pleasing and...
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This article takes an in depth look at locks and their use.
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A lock is a mechanism designed to connect an opening to its frame using a latch, solid cylinder, bolt, or some other form of a solid metal plunger that extends into the strike. They are metal devices that prevent entry or access for privacy, security, or safety reasons. The mechanism of a lock holds or moves a latch, bolt, or shackle away from or into the lock position.
The term lock is used to describe any type of device that is attached as an extra security measure and includes a long list of padlocks, combination locks, door locks, dead bolts, restraining bolts, electric locks, and key locks. The mechanism of a lock is the internal structure of a lock, which can be warded, pin tumbler, spindle, or disk tumbler. Lock mechanisms can be categorized as key operated, combination, or electric.
Prior to the modern age, all locks were mechanical and used levers, wheels, gears, and cams. Over the last hundred years, locks have become very sophisticated with programming, electronic mechanisms, and various forms of automatic locking methods.
The various types of locks have a similar function: keeping things in or out. They come in designs, forms, and configurations to specifically fit the needs of an application and are carefully installed to ensure smooth operation and efficiency. The materials used to produce a lock determine whether the lock is low security grade or high security grade since low security grade locks are made of inexpensive materials and are mass produced.
Locks that are designed for a special purpose begin with an understanding of the application where they will be placed. They are engineered from high quality materials that ensure a secure and perfect fit. Unlike locks purchased at the local home improvement store, high security locks are required to meet an established set of standards and are capable of performing in the most abusive conditions.
The metals used to make key locks include brass and zinc for the internal mechanism, with steel for the cam that protrudes from the lock into the striker on the door frame. The casing for the key lock can be made of a variety of materials including brass, chrome, steel, nickel, and alloys of those metals.
For standard tumbler key locks, the key is made first. Keys have five high points that are cut at differing levels, which are identified by numbers that can number from one to seven. In a normal five tumbler lock, there are 1024 different possible combinations of levels. Inside the key mechanism are pins that line up with the levels of the key. When the correct leveled key is inserted, it is allowed to rotate by the pins, which impede a key with incorrect levels. This function can be seen in the diagram below.
The most difficult part of the manufacture of a key lock is the pins, which have to have exceptionally precise tolerances within ± 0.001 of an inch. In the image below, the tiny pins can be seen resting on the teeth of the key, with the second set of pins and springs placed above them. Note that the pins have notches cut below their top that have to be precisely and carefully machined.
The key cylinder is where the key is inserted to move the pins to retract the plunger from the striker. It is the body of the lock and in rotational locks it is round.
The part of the lock that moves into the strike plate has several names, which include latch, bolt, and plunger. The name that is used depends on the manufacturer and the designer of the lock. It is the portion of a key lock that extends into the door frame and must be perfectly matched in order to securely fit into the strike. The latch on the deadbolt key lock below can be seen on the left of the image.
The strike plate is where the plunger or bolt is inserted into the frame of the door. It is attached to the door frame and comes in several varieties depending on the required level of security. Strike plates are made of heavy duty metal and require a great deal of force to be removed. They can have extra security measures that prevent the bolt from being retracted without engaging the lock.
The earliest form of key lock was the warded lock, or ward lock, which used a set of obstructions called wards. The key of a ward lock has cut out sections that are capable of passing through the wards. For places that need more security, the number of wards is complex and intricate, making it very difficult to open a door without the key. The type of key can be seen in the diagram below.
A way to get around ward locks is the skeleton key that has a single cut out capable of bypassing all of the wards.
Combination locks are opened by aligning a succession of discs in the proper order, with the most common combination locks having an internal mechanism of interconnected discs. In order to open the lock, the discs turn and stop in a preprogrammed position or notch. The discs are separated by nylon or plastic discs that allow them to turn independently. There is one wheel or disc for each number selected on the dial.
There are two varieties of combination locks, which are keyed or hand. Normally, keypad combination locks require a set of numbers to be entered using buttons on the face of the lock. The internal mechanism of keypad locks is similar to padlocks or dial combination locks.
A necessity for combination locks is that they are made of corrosion and rust proof materials such as plated or coated cold rolled steel or stainless steel. They are made to last a lifetime without the need for repair or replacement.
The lock case of a combination lock houses the lock’s mechanism and protects it from being damaged by force or the elements. It is made of durable metals such as various types of steel alloys.
Keyless combination locks can have a dial or set of thumb screws that turn the discs in the proper order. Dial combination locks are numbered from 1 to 59. When a number is selected on the dial, it aligns the discs to open the lock.
The dial turns a shaft or spindle upon which the discs or wheels are mounted. The rotation of the shaft is similar to the rotation of a key. Instead of lining up pins in a combination lock, the shaft lines up the discs. As the dial and shaft turn, the discs line up in accordance with the selected number on the dial.
In higher security combination locks, above the discs or wheels is a fence attached to a lever. The location and position of the fence is designed to prevent a door from being engaged without the proper combination. When the correct numbers are entered and the wheels or discs line up, the fence falls into a slot formed by the aligned discs allowing the handle on the door to be opened.
Electric door locks are a method for adding additional automation to the locking and unlocking of doors. They are a new and improved way to keep places secure and remove the need for a key. The attraction of electric door locks is the ability to remotely lock and unlock doors using a phone, laptop, or another form of electrical device.
The power supply for electric locks runs through the core of the door and frame to the power supply and access control. Other forms of electric locks are self contained without the need to connect to a power supply and have a replaceable battery.
The forms of electric locks can have the same configuration as traditional door locks with plungers, latches, or bolts that are activated by the electrical system. They operate on the same principle as a solenoid. When activated, they push the plunger into the strike. Other types of electric locks are magnetic with a magnet attached to the frame and a piece of metal on the door. They are capable of holding a door closed using hundreds of pounds of force. The negative aspect of magnetic locks is when the magnet is deactivated, the door is left unsecured.
A deadbolt has to be locked and unlocked by hand and is safer and more durable than other forms of locks. The mechanism of a deadbolt includes a solid sturdy metal bolt that slides into the strike on the door frame. The strike on a deadbolt normally extends deeper into the door frame strike, which makes them more difficult to break past.
The different forms of deadbolts include single cylinder, double cylinder, one sided, and keypad. Single cylinder deadbolts have a key slot on one side and a turning mechanism on the other. Double cylinder deadbolts have a key slot on both sides. One sided deadbolts can only be locked from one side of the door. Keypad deadbolts have a keypad with numbers for entering a code.
There are an endless number of locks due to the many different levels of security. The range of locks runs from simple locks used to secure cabinets to ones designed to incarcerate prisoners or protect valuables. The common lock found in homes can usually be purchased online or at a home improvement store. This is not possible for specialty locks that are individually designed to fit the requirements of high level security applications.
In the area of the common household lock, there are variations in the type of security provided based on the quality of the materials used to produce the lock. Additionally, whether the lock is manufactured for household use or high security, the appearance of the lock may be a factor depending on where it is to be located.
The most complete listing of locks will not include all of the different types since there are new designs, security parameters, and applications that are constantly being developed.
As with all forms of locks, there are many different types of cabinet locks for securing cabinet doors. A few of the common types of cabinet locks are magnetic and latch for home cabinets. More secure forms for cabinet locks are available for business cabinets that have bolts, cylinders, combinations, and latches. Each of these are designed for a specific application and level of security.
Latch cabinet locks have a latch and catch that prevent the cabinet door from being opened. The catch is placed on the inside of the cabinet door on the frame, for some versions of latch cabinet locks. Other forms have magnets and tabs.
Magnetic cabinet locks use magnets to hold the door of a cabinet closed. The magnetic component is placed on the frame of the cabinet. A metal piece is attached to the door. When they are in close proximity, the metal piece is pulled to the magnet. Magnet locked cabinet doors can be opened by simply pulling on the handle of the cabinet door.
Cam cabinet locks are a secure form of cabinet lock that does not affect the outward appearance of a cabinet. They are cylindrical locks that are ideal for wooden cabinets. Their metal tube has a hole in one side that secures the tongue of the bolt. They can be positioned everywhere on a cabinet including the joints. After a cabinet is completely assembled, they are barely noticeable.
Double door cabinet locks have an active door and fixed door, which is secured to the active door after being closed. The active door is the door that has a cam lock or some other form of a keyed lock. When the cabinet is unlocked, the active door is unlocked with a key while the fixed door is unlocked by hand.
Another form of double cabinet lock has one key but two bolts. When the key is turned, two plungers or bolts move into the strike to lock two doors, as can be seen in the image below on the left.
Push cabinet locks are installed on the inside of a cabinet door. The component that connects the door to the catch is a one piece bracket with a shaft and a ball. The catch has a clasp that grips the ball when it is pushed into it. Once connected, the cabinet door is held securely in place until a small amount of force is applied to remove the ball bracket from the catch.
Cam locks have a metal plate, or cam, that is attached beneath the locking mechanism. When a key is inserted and turned 90o, the metal plate secures the frame and the door. There are two types of cam locks, which are standard and tubular. A standard cam lock functions like any other form of pin key lock. Tubular cam lock has a tubular pin system where the pins are placed horizontally.
The benefits of cam locks include their affordability and practicality to provide extra security for cabinets, desk drawers, filing cabinets, vending machines, mailboxes, and cash boxes. They are used for commercial, residential, and industrial applications.
The center of the mechanism of a cylinder lock is its cylinder. When the key is inserted and the cylinder is turned, the cam pulls the bolt in and opens the door. When the cylinder is turned in the opposite direction, the cam releases the bolt to secure and lock the door.
A cylinder lock has a pin and tumbler design where the key aligns the pins to move the cam and bolt. The pins are in pairs positioned along the length of the cylinder and rest on the bottom of the cylinder when no key is inserted. The pins are positioned one on top of the other with a spring located above them. When the proper key is inserted and turned, it pushes the pins upward. The image below shows a cross section of a cylinder lock with the positioning of the pins and cam.
The term door lock covers an endless number of mechanisms and devices designed to prevent entry or access. They have latches, bolts, or plungers that are mounted in the door that cross between the door and its frame to create a secure and tight connection. A door lock mechanism can be mechanical, magnetic, electronic, or automated depending on its purpose and design.
The common door lock is an essential part of any construction project and is designed for safety, protection, and control of entry to a building or cabinet. The choice of a door lock depends on the level of security required by a facility, which can range from family residences to a vault, safe, or private enclosure.
Biometric locks are a unique form of lock that are designed for exceptionally high security applications. Their design radically restricts entry to a select group of people who have the appropriate physical authorized credentials. Biometric door locks can include fingerprint and retina scanners and voice detectors. They cannot be hacked or picked and provide absolute and total security.
Keyless locks have a keypad that requires a code to be entered to release the locking mechanism. They are a more sophisticated form of lock and are referred to as smart locks. Keyless locks are programmable, automatic, and include Wifi and app integration. The purpose of keyless locks is to remove the need to carry keys and for extra security since, aside from brutal force, keyless locks are impossible to pick or circumvent.
The code on a keyless lock can be easily changed to accommodate a variety of conditions from providing entry to a home sitter while on vacation to individual codes for each member of the residence or office. They are powered by batteries including 9V, AA, and AAA, which can be easily and quickly changed to provide continuous and uninterrupted power.
Although keyless locks are advertised as not requiring a key, some forms come with a key backup for special situations or when the battery is dead. Additionally, keyless locks can be programmed to lock after a preset period of time. They are backlit for easy visibility in darkness or low light conditions.
A mortise lock is installed inside a door and requires cutting a shape or pocket. For cylindrical locks, a hole is cut through the door, which is unlike a mortise that goes into the door and not through. An example of a mortise can be seen in the image below.
To open a mortise locked door, a handle or knob connected to a spindle rotates the spindle to disconnect the bolt from the strike plate on the door frame, which holds the locking and latch bolts. When a key is inserted and turned, it rotates a cylinder to retract the latch.
Mortise locks are different from the standard cylindrical lock and have distinct parts, which are the lock body, knob, spindle, cylinder lock, and strike plate.
Mortice locks are used in a wide range of applications due to their strength, endurance, reliability, and ability to withstand constant use and abuse. Their mechanism is made of solid metal components with large springs.
OEM manufacturers produce locks for other companies to be marketed under their brand name. The use of OEMs rests on their ability to produce locks at a lower cost. OEM locks cover the full range of locks and include cam locks, vending locks, padlocks, parking meter locks, cabinet locks, switch locks, and electronic locks. Every form or type of lock can be produced by an OEM company using the specifications of the receiving company.
By using an OEM manufacturer, companies are able to expand their operation without having to add extra labor, space, or facilities. The OEM produces high quality locks at a low cost, which helps the marketing company sell their products at a lower cost. With OEM locks, several million keys and code combinations are possible to ensure that the locks are secure, safe, and reliable.
Additionally, OEM companies use high quality raw materials that relieves the marketing company of another expense. Locks are produced to meet the exact design of the marketing company as well as its quality. OEM locks have several different key types and combinations, which further increases their security and safety.
Tubular locks are known as radial and circle pin tumbler locks, which are names that refer to the keyhole’s round shape. They are also called Ace locks since Ace was the company that introduced them. The name tubular refers to the keyway configuration for the lock that has a ring shaped hole with a metal cylinder in the middle.
In the ring of a tubular lock are six to eight pins, with seven or eight being the most common. Regardless of the round shape, tubular locks have pins like a cylinder lock. The difference between the locks is the orientation of the pins. In a cylinder lock, the pins are placed vertically while in a tubular lock, the pins are placed horizontally. The plug that holds the pins rests on the same cylinder that holds the driver pins and springs.
The key for a tubular lock is circular with an opening in the center and grooves cut into the outside of the circular shape. To identify how to insert the key, the key has a notch to match the notch in the keyway. When the key is inserted in the keyhole, it depresses the pins.
The image below depicts the horizontal placement of the pairs of pins and their springs as the key is inserted into the lock’s notch.
In most cases, vending machine locks are a category of the tubular lock. They are made of exceptionally sturdy material as a preventative measure against theft. Vending machine locks are a specialty lock used to secure pay phones, ATM machines, and computers. Since they are a security measure for valuable devices or machines that contain money, they are made from hardened steel or stainless steel.
Due to the many places where vending machine locks are used, they are specially coated for protection against corrosion, rust, and tampering. The use of tubular locks is due to the cylindrical design of the key, which makes it difficult to pick the lock. Also, tubular locks are less expensive than standard cylinder locks but provide the same type of security and protection.
Aside from tubular locks, vending machine locks can have the same standard deadbolt designs, combination, and spring latch locks. Many vending machine manufacturers have the locks for their machines custom made as an extra level of security.
Euro cylinder locks, also known as barrel, profile cylinder, and pin tumbler locks, are very popular in Europe and are very easy to install and replace. They can be locked from both sides and have a keyhole at both ends. It is referred to as a double key lock since it controls access from both sides of the door. If a key is left on one side of the lock, it will not be possible to unlock it from the other side. Euro cylinder locks are very popular due to their versatility and ability to incorporate deadbolts.
A key factor in the selection of a lock is the material used to manufacture it. In most cases steel or stainless steel are used due to their strength, durability, reliability, and ability to withstand constant use. The type of material determines the selling price of a lock, with copper being a superior material but very expensive.
The quality and performance of a lock are determined by the metal used to produce it. Locks sold at home improvement centers are mass produced and do not have the security level associated with biometrics and other high security locks.
As with most applications, stainless steel is the number one choice for manufacturing locks due to its exceptional durability and corrosion resistance. The bright shine of stainless steel never fades and is available in a wide range of grades to fit the many varieties of locks. Austenitic grades of stainless steel never rust but are non-magnetic.
Copper is one of the most used metals for the manufacture of locks due to its excellent mechanical properties, corrosion and rust resistance, and ability to be easily processed. Aside from its properties, copper has an exceptional appearance for handles and decorative parts of locks. It offers a smooth surface, good density, and no pores or holes.
Zinc is not a typical metal used to manufacture locks but is ideal for making complicated and complex components. It is widely used in locks to provide an excellent appearance and its decorative qualities.
The many grades of steel offer lock manufacturers sufficient flexibility to choose the right metal to fit the type of lock. Steel has excellent strength, durability, and resilience, which is the reason it is so widely used to produce lock components. The appearance of steel does not make it applicable as ornamentation or decoration.
As an extra level of protection for locks and to increase their time of usefulness, their metals are covered with a protective film that is electroplated, coated, or chemically oxidized. Surface treatments are anti-corrosive, improve the appearance of a lock, and increase their durability. To ensure the quality of lock surface coatings, the thickness, adhesion, susceptibility to salt spray, and moisture resistance are tested.
The most critical feature related to coatings is their appearance, which has to enhance a lock and give it eye appeal, especially if it is in a highly visible location.
Choosing a lock can be a complicated process especially when it will be an important part of security measures for a location. In most cases, locksmiths take several factors into consideration when determining the type of lock that would be best for an application.
The primary functions of locks are privacy, security, entry, and smooth passage. The room where the lock will be installed determines the quality and type of lock that will be used. In special cases, such as with the elderly or disabled, easy operation can be important as well.
How durable a lock needs to be is primarily based on where it will be located and how often it will be used. Storage rooms, lock boxes and cabinets for valuables, and commercial entrances require locks that are far more durable than an entry door for a home that may be used once or twice a day.
The grades of locks are ANSI grades 1 and 2, with grade 1 locks being of the highest level and are intended for commercial security. Grade 1 locks are ideal for high traffic locations and are capable of withstanding hundreds of thousands of openings. Grade 2 can be used for commercial traffic as well, but where the traffic is less intense.
The appearance of a lock depends a great deal on where it will be located. There is an endless number of shapes, sizes, coatings, metals, and mechanisms available to help determine if a lock has the right appeal for where it will be installed.
This aspect of the choosing process is strangely enough the least important. Choosing the least expensive lock made of inferior materials can lead to difficulties. The key to the decision process is functionality. A cheap lock that is to protect valuables can be costly in the long run.
Poorly constructed and inferior doors can make a high quality lock useless. If a door has a hollow core or weak frame, it will fall apart long before any lock does.
Building codes and fire regulations stipulate the types of locks that are preferred for safety and protection. Locks that require a key on both sides are considered to be unsafe. On the package of a lock are the Underwriter Laboratories (UL) standards, which indicate that a lock meets fire safety standards.
A concealed hinge, also known as a hidden or European hinge, is a type of hinge that has parts invisible to the onlooker when the door is closed. They are commonly used in cabinet doors to add an aesthetically pleasing and...
A continuous hinge is an extended single unit hinge that spans the full length of a door, cabinet, lid, or enclosure entrance. They are made of lightweight metals and can be cut to fit the size of any opening...
A friction hinge works by creating a specific tolerance in between the mechanical components. It works based on the principle of torque that can be achieved by applying a desired amount of force. Some other additions to these hinges such as...
A hinge is a machine element that connects two bodies allowing angular movement about a fixed axis of rotation, all the while preventing translations and rotations on the remaining two axes. A hinge can be considered as a journal bearing with only one degree of freedom where a shaft is rotating in a hole...
Latches are mechanical components that allow the temporary joining of parts that are moving relative to each other. They are actuated to release the coupling and allow the two parts to separate. Latches are mostly seen on doors and enclosure openings...
A spring hinge is a self-closing hinge that automatically closes two connected workpieces using the action of a spring that is loaded into the hinge's barrel. They can be found in a wide variety of products such as...
A spring latch is a mechanical device that is utilized in the joining of two separate components in order to prevent movement or opening. A spring latch is locked with a spring compression so that it will not be released...