Butter's System is a mechanism using a number of flat detainers which preferably are sliders, having a shallow slot in one edge. A crank is operated by a high point on the bolt, instead of using a bolt stump. Turning the key presses the high point on the bolt lath(tail) against one end of the crank, but this end can only move to pass over the high point if its toe end (a narrow probe) can enter the gate slots in all the sliders. As the key turns, its bit also raises the sliders - the correct key raising the sliders to the correct heights. Being edge notched, more than one gate can be made in any slider, and extra gates may be adjacent or separate. This allows considerable masterkeying possibilities. Frederick J Butter was sometime employed by Chubb & Sons, then was for many years chief designer for Josiah Parkes & Sons (Union Locks). He invented this system in the 1920's. (It pre-dates Chubb's end-gated detainer system, used in the 'Castle' range, by some years.) It has been extensively used by Parkes, with models having 3, 4, or 5 sliders, with, and usually without, a barrel and curtain; wards are not usually used. It was certainly in production until recently. Not having a current catalogue, I cannot confirm there are still Butter's System models in production. Chubb took over Parkes and other companies, then Yale (owned at the time by Williams Holdings) took over the Chubb Group. With Chubb, Union, Yale, Ingersol, Lips, and a few others, in common ownership (now ASSA-Abloy), there has been rationalisation of production and models. Butter's System offers a relatively robust lock with more differs than low-priced conventional lever locks, and considerable capability for masterkeying, so it has long been popular for many institutional uses. Butter died in April 1963. (The parts of the former Chubb Group which are not part of ASSA-Abloy are the manned security and alarm divisions.)
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20 years ago