Ingersoll Locks Ltd do not make ordinary locks: they are a world-leading manufacturer of high security locks and as such supply banks, military establishments, government agencies, transport firms and security-conscious industrial and commercial companies as well as householders. The award-winning range of Impregnable padlocks illustrates the creative approach to design which has helped to earn the company its reputation.
The original Ingersoll patent which led to the development of the Impregnable range was granted in 1949 for a method of securing the U-shaped shackle into the lock by means of two ball bearings being driven by a cam mechanism to engage in grooves in the toe and heel of the shackle. Similar methods have since been adopted by many other manufacturers. The body of the padlock is made up of steel laminations which are locked together, copper brazed, case hardened and finished in dull nickel chrome, leaving an internal chamber to house the unique Ingersoll 10-lever cylinder which is used in nearly all Ingersoll locks. This cylinder has at least twice as many levers as most other locks, providing an exclusive combination for each user and being highly resistant to picking devices, skeleton keys or drilling.
This left the shackle itself as the most vulnerable point and Ingersoll - always aiming to keep one jump ahead of the thieves - set about trying to find a method of toughening the shackle. But every attempt to improve the metal's resistance in one way meant compromise in another direction, and compromise is not permissible where security is concerned. So it was decided to tackle the problem in an entirely different way to protect the shackle from attack by bringing the shoulders of the padlock case up to completely surround it. This anti-wedge version was introduced in 1967, together with a patented design of notched padlock bar to fit tightly over the top of the padlock. A high shoulder version, open at the front and back only, was marketed in 1968. Standard open and close shackle models make up the range, the production of the different bodies being simplified by their laminated construction - with additional layers simply added to the basic shape for each model. The shackle is cyanide-hardened steel, with a tough industrial chrome plating to resist cutting. The padlocks cannot be "shocked" open and even if a way of obtaining leverage is discovered will withstand pull pressures of more than four tons.
These padlocks are so secure that the United States Government has decided to standardise on them for all high security jobs requiring padlocks. Among the tests which the locks had to endure before winning this approval was the insertion of dynamite in holes drilled in the case in an attempt to blow off the shackle, heating for an hour in a furnace at 2000 degrees F, and trying to pick the lock with special tools and with the assistance of radiographs. Another satisfied American customer is Con Edison, who before fitting Ingersoll padlocks lost $450,000 worth of tools in one year from tool carts in the streets of New York: in the first ten months after fitting ''Impregnable'' locks, losses were only $500.
Ingersoll recognise that security does not begin and end with a good lock The company issues no key blanks to the trade and will itself only provide a duplicate key on receipt of a request bearing the signature previously agreed with the individual customer. Because the special 10-lever cylinder is used in other Ingersoll locks, the customer is able to have one key which will operate different types of locks. The locks can be arranged in master keyed groups so that, for instance, a head of departmen can open only the locks in his department while the managing director has a master key which will open locks in every department.
Ingersoll are fully aware that because their locks have such a high reputation and are therefore used for the most difficult jobs, these installations are the target of the most intelligent and persistent thieves, terrorists and spies. "We can never sit back, for villains are always finding new ways of attacking our locks, and we have just got to keep ahead. We cannot afford one mistake, for our whole reputation is at stake," says Robert Judd, Ingersoll's sales director. ''We therefore keep in close touch with the police and with insurance companies, and we make sure that we are told of any burglary or attempted burglary which involves an Ingersoll lock in any way.
''We recognise that security is a concept, and cannot be isolated into particular pieces of hardware: we therefore offer an advisory service to customers to analyse their whole lock security problem, even when it does not concern our products."