The Lock That Changed Locks

Of course, locks are as old as civilization and were first made of wood. It was in the reign of Alfred the Great that locks were first manufactured in England and the United States, but there was little improvement in their construction until the end of the eighteenth century.

Since that time, many marvelous developments have been made in locks makers in lock inventions. The Yale lock brought about a revolution in the lock making industry. Up to that time, good locks had been made by hand and they were very expensive. The invention of the cylinder lock made it possible to use mass production methods in making really fine locks affordable. Nowadays, such locks are available to rich and poor alike.

The middle of the nineteenth century saw the development of the Yale cylinder lock. It was first patented by Linus Yale, Sr., a manufacturer of bank locks, in 1844. His son, Linus Yale, Jr., improved the lock and took out two other patents in 1861 and 1865.

It has been further improved upon since that time, but it still works on the same principle. It consists of a shell, or case, in which there is a rotating cylinder, called a plug. The key is inserted in the plug.

No matter how strong and well designed a lock may be, the keyhole always presents a weak point. Many devices to hide the keyhole, and even to take the place of a lock proper, have been tried. However, the only one in general use is the ordinary combination lock.

This is a lock in which the arranging of the internal parts in their proper positions is done from the outside by merely using numbers or letters in their right order.

The numbers show on a disc which is usually marked from 1 to 100. In this case, the only key is a secret -- the right numbers and in the right order that they are to be used.

Where letters are used, the lock may be set to open only when a particular word is spelled.

These improvements made the combination lock almost unpickable. There still remains a secret, which, if known, would open any lock, and burglars sometimes used torture to force the possessor of such secrets to reveal it to them.

As shown in this first picture, a common old fashioned tumbler lock works on a pivot. 

Then, inventors took another step and produced the time lock, which can be opened only at certain hours selected in advance, just as we set our alarm clocks to ring the next morning.  Still the burglar found a way of introducing liquid explosives into the space surrounding the lock spindle (the bolt which passes from the outside combination dial to the tumblers inside the door).

The problem was to make the introduction of these explosives impossible, and to do this the spindle-holes had to be done away with.   This is done by a motor device working with a time lock.

The motor throws the bolts and draws them back according to the setting of the time lock.  The only way to overcome a modern vault door is to use force destroying the whole structure.

Locks are often master keyed.  Each lock in a master keyed series has its own key which fits no other lock in the series, but there is a well a master key which fits all the locks in the series.  this is a convenicne in buildings with many locks.  Thus, in a large office building, each tenant can unlock only his own door.  While a master key will only lock the locks on a particular floor, and additionally a master key can unlock every door on each floor.

Today there are many advances in locks and lock making.  There are locks for doors, safes, safety-deposit boxes, cars, ignition switches and a great many other things.  The manufacturers of locks are doing all in their power to safeguard our treasures and they are succeeding as never before.