CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF LOCKS AND KEYS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Herbert Allman at the Office of the
Commissioners of Patents, with his Petition, on the 81st December
1866.
I, HERBERT ALLMAN, of 10, Ampthill Square, London, in the County of
Middlesex, Civil Engineer, do hereby declare the nature of the said Invention
for "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF LOCKS AND KEYS," to be as
follows:-
My improvements may be described as relating to the form of locks
commonly called lever or tumbler locks, and in the keys used therewith, and
may be detailed as follows:-
First, I form the levers and tumblers in a way and of such a configuration
that the key in making one revolution round the drill pin comes more than
once in contact with the said tumbler or levers.
Secondly, I use spring or plain washers between the said levers or tumblers,
so as to enable the tumblers to work free one of the other, and enable them
to retain the position which may be given them by the action of the key bit
when the tumblers are without springs.
Thirdly, I use in the construction of the said levers or tumblers or other
parts of the said locks the material commonly known as yellow metal or
Muntz's metal.
Fourthly, I coat or electrotype sheets of metal with tin, zinc, copper, brass,
or silver, and press the herein described tumblers from the said sheets of
metal so prepared.

page_text: Fifthly, I make one or more of the said levers or tumblers longer from the
centre of rotation to the stump face than the remainder of the said levers, so
that when the "stump" is pressed against the levers it will reach the longer
ones first, compelling such long levers to be adjusted for the passage of the
stump first or before the others.
Sixthly, I form one or more of these said longer levers of such a shape or
configuration that when they are lifted or adjusted by the key or pick-lock to
admit of the passage of the "stump" they will then assume or occupy such
a position as to close or block the keyhole.
Seventhly, I employ two or more sets of tumblers or single tumblers gearing
into each other, so that the action of the one moved by the key or pick-lock
shall cause the other or others to close the keyhole or otherwise impede the
action of the pick-lock.
Eighthly, I construct the key tubes of steel tube, and solder thereto the
"bits" and "bows."
Ninthly, I employ a spring or pressure on the levers, so that they will
remain under the influence of friction in the position into which the said levers
may be moved by the key or pick-lock.
Tenthly, I polish, scour, or burnish the plates of sheet metal, out of which
I press the various parts of the locks previous to or before such act of pressing
or cutting.
Finally, I stamp the keys in some instances out of the before specified
yellow metal.
I would more fully explain the fifth and sixth improvements to be arrange-
ments and forms of levers to guard against the introduction of picks through
the keyhole, the action of which may be described as follows:-One or more
of the levers being longer than the others (from the centre on which they
revolve to the stump face) must be first adjusted to allow the "stump" to pass;
but in this position a part of the said levers are drawn across the keyhole so
as to obstruct the action of a pick on the other levers.