Locks, Safes, Grilles and Bars
A brief history of locks...
See Wikipedia for a much more in depth definition...
Securing one's property has long been a concern. Early solutions included knots to either detect, like the Thief knot, or hamper, like the Gordian Knot. The Gordian Knot is a legend of Phrygian Gordium associated with Alexander the Great. It is often used as a metaphor for an intractable problem solved by a bold stroke). Historians are unsure where the first lock was invented, but evidence suggests that locks initially developed independently in the Egyptian, Greek, and Roman civilizations. Wooden locks and keys were in use as early as 4,000 years ago in Assyria.
The first known lock with a key is a pin lock. The lock is strung on a rope hanging out of a hole in a door. A cylinder of wood with a hole drilled through its axis is the key, the length of the cylinder being the critical factor. The key is inserted into the hole and the bolt is pushed the correct distance. To lock the door the rope was pulled to extract the key cylinder, simultaneously pulling the bolt closed. This type of lock is still in use in certain parts of the world. Puerto Rico still uses this system. A disadvantage of this lock is that a vandal can push the rope into the hole — an ancient equivalent of putting glue into a lock.
Next, the warded lock was invented in China. In the Middle Ages, it came to Europe.
This lock is still used in modern times when the security required is not high and cost is a significant factor. This lock has become the most recognizable lock/key design in the Western world.
Lock puzzles were used to obscure the locking mechanism or even provide a non-functioning lock for the thief to waste time on.
In the early 1900s a wooden pin lock with a wood key was discovered in Egypt and is believed to have been used in 250 B.C.
Early improvements in pin locks included increasing the number of pins to increase security, and changing the orientation of the pins to allow the key to provide the unlocking force instead of a rope, thus establishing the principles of the modern pin tumbler lock.
Locks may be entirely mechanical, or electromechanical. They may be operated by turning some form of removable key, by keying or dialling in a combination which directly or via electromechanical means operates the lock, with some form of magnetic or other card reader, or by moving a part on a safety lock intended to prevent accidental operation rather than to prevent unauthorized access.
Combination lock
A combination lock is a type of lock in which a sequence of numbers or symbols is used to open the lock. The sequence may be entered using a single rotating dial which interacts with several discs or cams, by using a set of several rotating discs with inscribed numerals which directly interact with the locking mechanism, or through an electronic or mechanical keypad.
Warded lock
The warded lock is one of the earliest types of locks. It said to have been developed in China.
Pin-tumbler lock
The Pin-tumbler lock is the most widespread lock in the western world. Pin-tumbler locks have been around in some form since 2000 BCE. The Egyptian form of this lock was large, heavy, and made of wood, with pins made of metal, usually bronze, but sometimes iron. This design in its modern form was first patented in 1805 in England. The patent holder was an American named A.O. Stansbury. In the middle of the 18th century, the American locksmiths Linus Yale Sr. and his son, Linus Yale Jr., refined the lock design into the form recognizable today. These early versions of the pin-tumbler lock were expensive to produce, and did not become widely available until mass production became feasible.
Wafer-tumbler lock
The first patent for the wafer lock was issued in the United States in 1868 to P.S. Felter. The wafer lock is relatively inexpensive to produce and is often used in automobiles and cabinetry. This type of lock is generally made of die-cast zinc alloy.
Lever locks
Lever locks were invented in Europe in the 17th century. This is a popular lock type for safes and North American prisons today, as they are generally built of strong materials. They are also used as door locks in some countries. This is the type of lock that replaced the medieval warded lock in the 19th century. Robert Barron of England patented the double-acting lever in 1778. Jeremiah Chubb would follow with his own detector lock in 1818.
Other types
There are also many other types of lock, such as warded locks, tubular locks, electronic locks (itself a huge area) and also many variations of the various types, such as dimple locks, which are a variation on Yale's original cylinder lock in which the pins interact with the side of the key rather than the edge, "laser track" car locks, which are a variation on wafer locks, and some higher security lever locks also include the types of warding found on warded locks.