Year: 1887

page_text: Date of Application, 18th May, 1887
Complete Left, 9th Feb., 1888
Complete Accepted, 9th Mar., 1888
I, JOHN BURDON, of Muirmadkin, Bellshill, in the County of Lanark, North
Britain, Blacksmith, do hereby declare the nature of this invention to be as
follows, that is to say :-
My said Invention has for its object, by the application of novel devices, to increase
the security of locks, and in particular to frustrate attempts to pick them with the aid
of pressure applied to the bolts.
In carrying out my Invention 1 provide the bolt of a lock with two small bolts
which when the main bolt is shot project outwards at right angles to the main bolt
and prevent its withdrawal from the socket in the striking plate into which it is shot.
The main bolt is made hollow and the small bolts are moved by levers centered on the
plate or thin side of the main bolt, these levers being moved by means of pins on them
which are acted on by cam slots in a turning piece also centered on the plate of the
bolt.
The turning piece is itself moved by means of a pin on it which projects into
a slot in a lever like a tumbler lever arranged and shaped to be acted on by the key.
The lever may be one of a set of ordinary tumbler levers, and is by preference made
with an additional notched slot, in combination with which there is a stump on an
additional spring-pressed lever which is acted on by a cam-shaped edge on one of the
tumbler levers or on a separate lever acted on by the key. The additional spring-
pressed lever with the stump on it acting in the notched slot of the tumbler lever and
the cam-shaped edge acting thereon, are arranged so that the lever with the cam-
shaped edge has to be moved a considerable distance and to a precise point when
unlocking or withdrawing the bolt by means of the key, before the small bolts can be
withdrawn into the main bolt, and the main bolt cannot be moved until the small bolts
are so withdrawn. The main bolt is by preference made with shoulders to prevent
it from being pushed out too far, and from being moved in a manner to injure the
levers or tumblers.
The improvements are applicable to various kinds of locks whether made with
tumblers or wards or other security devices.
EDMUND HUNT,
Applicant's Agent.

page_text: I, JOHN BURDON, of Muirmadkin, Bellshill, in the County of Lanark, North
Britain, Blacksmith, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement, that is to say :--
My said Invention has for its object, by the application of novel devices, to increase
the security of locks, and in particular to frustrate attempts to pick them with the aid
of pressure applied to the bolts.
And in order that my said Invention and the manner of performing the same may
be properly understood 1 hereunto append a sheet of explanatory drawing to be
hereinafter referred to and showing two modifications of my improved lock.
Figure, 1, on the accompanying sheet of drawings is an elevation of the lock as
with the closing plate removed and with the bolt in its withdrawn position. Figure, 2,
is a similar view slightly modified in details but with the bolt in' section and in its
shot position; and figure, 3, is an inverted horizontal section corresponding to
figure, 2, but with the closing plate in position. In these drawings the same reference
numerals are used to mark the same or like parts wherever they are repeated.
In carrying out my Invention I provide the bolt, 4, of a lock with two small
bolts, 5, 6, which when the main bolt, 4, is shot project outwards at right angles to
the main bolt, 4, and prevent its withdrawal from the socket in the striking plate or
bosshead (not shown) into which it is shot. The main bolt, 4, is made hollow and the
small bolts, 5, 6, are moved by levers, 7, 8, centered on the plate or thin side of the main
bolt, 4, these levers, 7, 8, being moved by means of pins, 9, 10, on them which are acted
on by cam slots in a turning piece, 11, also centered on the plate of the bolt, 4. The
turning piece, 11, is itself moved by means of a pin, 12, on it which projects into a
slot in a lever, 13, like a tumbler lever arranged and shaped to be acted on by the key.
The forward end of this lever, 13, may be pressed down by means of the well known
spring finger device, 14, acting on the pin, 15, as shown in figure, 1, and which
device is applied to all the tumbler levers in the lock. Or this may be effected as
shown in figure, 2, by making the cam-shaped part of the tumbler lever, 13, on which
the key acts, with a concentric continuation part, 16, on which the key will also act
to turn down the lever, 13. Another alternative device for the same purpose is also
shown being indicated by dotted lines in figure, 2, and consisting of a helical spring, 17,
one end of which is attached to the forward end of the lever, 13, and the other to a
fixed part of the lock. The lever, 13, may be made so as to act as one of the set of
ordinary tumbler levers and is, by preference, made with an additional notched slot, 18,
in combination with which there is a stump, 19, projecting on both sides of an
additional spring pressed lever, 20, centered on a fixed pin, 21, one end of the stump
lever, 20, being acted on by a cam-shaped edge indicated by a dotted line, 22, and
which is on one of the tumbler levers. The additional spring-pressed lever, 20,
with the stump, 19, on it acting in the notched slot, 18, of the lever, 13, and the cam-

page_text: shaped edge acting thereon, are arranged so that the tumbler lever has to be moved a
considerable distance and to a precise point when unlocking or withdrawing the
bolt, 4, by means of the key before the small bolts, 5, 6, can be withdrawn into the
main bolt, 4, and the main bolt, 4, cannot be moved until the small bolts are so with-
drawn. For this purpose the tumbler having on it the cam-shaped edge, 22, is made
with a downwardly projecting part, 23, which is pressed up by the key when first
acting on the tumbler. The main bolt, 4, is by preference made with shoulders, 24,
to prevent it from being pushed out too far, and from being moved in a manner to
injure the levers or tumblers.
The improvements are applicable to various kinds of locks whether made with
tumblers or wards or other security devices.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1-Fitting the bolt of a lock with small bolts which by means of levers and a piece
with cam slots are moved out when the bolt is shot and have to be withdrawn within
the bolt before the bolt itself can be withdrawn from the striking plate or boss head,
substantially as hereinbefore described.
2 Fitting a lock with a movable stump lever which locks one or more of the
tumblers or levers and which is itself moved by a cam edge on a tumbler or lever
shaped so as to be acted on by the key before the remaining tumblers or levers are
acted on substantially as hereinbefore described.
Dated this Eighth day of February 1888.
EDMUND HUNT,
Applicant's Agent.