Improvements in Door Locks.
Year: 1889

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by CLEMENT FELTON, of No. 164, King Street West,
in the City of Toronto, in the Province of Ontario, Canada, Locksmith.]
Improvements in Door Locks.
1, FREDERICK JOHN CHEESBROUGH of 15 Water Street Liverpool, in the County
of Lancaster, Patent Agent 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 :-
The object of the invention is to design a strongly constructed, simple, and
unpickable door-lock; and it consists, essentially, of a peculiarly formed independent
tumbler pivoted in the lock and designed to receive a very thin key inserted through
a sinall slit in the case of the lock, and arranged to revolve the tumbler so as to
operate the levers and bolt of the lock, substantially as hereinafter more particularly
explained.
Figure 1) is an outside view of a door-lock, partially broken, away, to expose the
special construction involved in my invention.
Figure 2) is a similar view of a night-latch, partially broken away, to expose the
special construction involved in my invention.
Figure 3) is a perspective detail of the tumbler.
"
"2
>> my improved bolt.
5) is a perspective view of my improved catch, showing it applied to a
door-jamb.
The great feature in my invention is the fact that I produce an extremely simple
and strongly-constructed lock which can be operated by a very thin key, and is
practically unpickable.
I make the case A, of sheet metal stamped into shape so that there shall be no
seams in the body of the case. This plan produces a very strong case, which is
practically unpickable. B is the bolt, which I make of T-iron so as to produce a
light and at the sune time extremely strong bolt, calculated to resist a great
pressure.
I do not claim anything peculiar in the arrangement of levers used in connection
with this lock, nor to the manner, in which the bolt is placed in position, but I
consider the peculiar form of my bolt a great advantage. C, is the tumbler,
having a thin slot, a, formed in it to receive the thin ond of the key D. The
ends of the tumbler C, are journaled in the side-plates of the case A, through
which thin slits are made to permit the insertion of the key D into the slot a of
the tumbler C. When the key is thus inserted in the tumbler C, the said tumbler
may be caused to revolve by turning the key D the tumbler operating the bolt B,
and at the same time, owing to the manner in which it holds the key, the said
key is strengthened so as to enable it-through very light-to work in conjunction
with the tumbler.
When my lock is made for a night-latch, I make the key-hole b, horizontal, and
locate over the said key-hole, inside of the case, a shield E, which effectually prevents
the insertion of any instrument by which the lock could be picked. Of course it
would not be possible to apply the shield E, to an ordinary lock, such as shown in
figure 1, as it is necessary, in an ordinary lock, that the key should be permitted to
revolve freely around on its axis, whereas in a night-latch it need only revolve
sufficiently for to throw the latch clear of the catch.
In Figure 3 I show a strong catch designed to be used in connection with my
improved lock. This catch consists of a Hanged block F, fitted on and securely
fastened so the jamb G of the door; a T-shaped slot d, being made in the block F,
to receive the T-shaped bolt B. I prefer to secure the flanged block F by means

page_text: of pins H, which are inserted through holes in one of the flanges and through
the door-jamb G, and are screwed into the flange located on the opposite side of
the jamb.
From this description it will be seen that I have produced a cheaply-constructed,
simple, and strong door-lock, which is practically unpickable.
Having no 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) A tumbler C, journaled in the case A. and designed to act upon the bolt B in
combination with a thin key D, fitting into a slot a formed in the tumbler C, and
designed to operate the levers of the lock; substantially as described.
2) A tambler C, journaled in the case A, and designed to act upon the boli B, a
shield E located parallel with the key-hole b, in combination with a thin key D, fitted
into a slot a, formed in the tumbler C, and designed to operate the levers of the lock,
substantially as described.
3) The combination with the mechanism of a door-lock, of the T-shaped bolt B,
substantially as described.
4) The combination, with the bolt of a door-lock, of a door-lock, of a flanged
block, securely fastened to the jamb G, and having a slot formed in it to receive
the said bolt, substantially as and for the purpose specified.
Dated the 13th day of November 1889.
FREDERICK JOHN CHEESBROUGH,