IMPROVEMENTS IN LOCKS
Year: 1860

page_text: LETTERS PATENT to George Hamilton, of 3, Royal Exchange, in the
City of London, for the Invention of "IMPROVEMENTS IN LOCKS."
Sealed the 30th April 1861, and dated the 2nd November 1860.
PROVISIONAL SPECIFICATION left by the said George Hamilton at
the Office of the Commissioners of Patents, with his Petition, on the
2nd November 1860.
I, GEORGE HAMILTON, of 3, Royal Exchange, in the City of London, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN LOCKS," to
be as follows:-
This Invention has for its object improvements in locks, and consists in
arranging the same in the manner herein-after described so that should the
bolt be pressed back for the purpose of picking the lock the bolt is imme-
diately stopped by an instrument put in motion by pressing back the bolt.
For this purpose I mount the tumblers on a moveable axis, the said axis
being fixed at one extremity of a bell crank lever, which is capable of turning
on a pin fixed in the lock plate, the springs of the tumblers tend constantly

page_text: to press them forward, but when pressure is applied to the bolt and through
it to the tumblers, the tumblers recede, the lever, on which their axis is
mounted, tipping on its pin or centre, and so bringing down its other ex-
tremity into a notch formed in the bolt, and in order that the tumblers may
be removed entirely out of contact with the projection or stump on the bolt,
should the pressure be continued, I incline the notch in the bolt, and the
extremity of the lever which locks into the same, so that the inclines may
give a further motion to the lever, and by so doing draw back the tumblers
through a greater space than that through which the bolt moves. Or in
place of this arrangement, I in some cases centre the tumblers on the
bolt, and I then mount the stump on a bell crank lever centered as before
on a pin fixed in the lock plate, the stump is thus enabled to yield when
pressure is applied to the bolt, and in yielding it brings down the other
extremity so as to lock the bolt as before. The end of the lever and the
notch in the bolt are as before inclined, consequently, should the pressure
on the bolt be continued the stump will be withdrawn out of contact with
the tumblers. A similar arrangement is applicable should slides, or similar
instruments, be employed in place of tumblers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Hamilton in the Great Seal Patent Office on the
1st May 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HAMILTON, of 3, Royal Exchange, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of November, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Hér heirs and successors, give and grant unto me,
the said George Hamilton, Her special licence that I, the said George
Hamilton, my executors, administrators, and assigns, or such others as I, the
srid George Hamilton, my executors, administrators, and assigns, should at
"any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN LOCKS," upon the condition (amongst others) that I, the

page_text: said George Hamilton, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and 'cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Hamilton, do hereby declare
the nature of: the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
This Invention has for its object improvements in locks, and consists in
arranging the same in the manner hereinafter described, so that should the
bolt be pressed back for the purpose of picking the lock the bolt is imme-
diately stopped by an instrument put in motion by pressing back the bolt.
For this purpose I mount the tumblers on a moveable axis the said axis being
fixed at one extremity of a bell crank lever, which is capable of turning on a pin
fixed in the lock plate, the springs of the tumblers tend constantly to press
them forward, but when pressure is applied to the bolt and through it to
the tumblers, the tumblers recede, the lever on which their axis is mounted
tipping on its pin or centre, and so bringing down its other extremity into
a notch formed in the bolt, and in order that the tumblers may be removed.
entirely out of contact with the projection or stump on the bolt, should the
pressure be continued, I incline the notch in the bolt and the extremity of
the lever which locks into the same, so that the inclines may give a further
motion to the lever and by :so doing, draw back the tumblers through a
greater space than that through which the bolt moves. Or in place of this
arrangement I in some cases centre the tumblers on the bolt, and I then
mount the stump on a bell crank lever centred as before on a pin fixed in
the lock plate, the stump is thus enabled to yield when pressure is applied
to the bolt and in yielding it brings down the other extremity, so as to lock
the bolt as before. The end of the lever and the notch in the bolt are as
before inclined, consequently should the pressure on the bolt be contained
the stump will be withdrawn out of contact with the tumblers.
arrangement is applicable should slides or similar instruments be employed
in place of tumblers.
:
A similar
And in order that my said Invention may be most fully understood and
readily carried into effect I will proceed to describe the Drawings hereunto

page_text: in
Figure 1 is a front view of a latch lock constructed according to my
Invention Figure 2 a plan, and Figure 3 ii a back view of the same,
the back plate being removed; Figure 4 is also a back view, the tumblers
having been removed; Figures 5 shew some of the parts separately, a is the
latch bolt; b is a spring which presses on the inner end of the bolt, so as to
force it outwards; c is a knob or handle for working the bolt; d is a stud
projecting from the front of the lock, by means of which a locking piece d
may be caused to enter one or other of the notches in the latch bolt a so
as to hold the said bolt any position in which it may be placed until it
is released by moving back the stud d; e is the bolt of the lock when it is.
shot, by means of the key it secures the latch bolt a, it is shewn in this
position in Figures 3 and 4 of the Drawings; it will be seen that this
locking is effected by the projection e' on the bolt e, which enters a recess.
formed for it in latch bolt a, thus when the bolt e is shot the projection el
coming against the latch bolt a throws it out beyond its original position
and there secures it, and when the lock bolt e is drawn back the projection e¹
by again coming against the latch bolt a throws it back to its former
position; is a stump fixed on the bolt; 9, 9, are tumblers, they are furnished
with springs g', g¹ and are centred on a pin h¹, mounted on the bell crank.
lever h, this lever is capable of turning on the pin i fixed in the lock plate
which also serves as a stud for the tumbler springs to act against. The
further extremity of the lever h, as will be seen, stands over the top of the
bolt e, and should this bolt be pressed back the stumpf pressing on the
tumblers g forces them back against the action of their springs, and so the
bell crank lever is caused to move, and its further end brought down so as
to enter a notch e² formed for it in the top of the bolt, thus when pressure
is put on the bolt to force it back, it immediately becomes locked so that
even should the tumblers be afterwards properly arranged the bolt will be
unable to go back. It will be seen also, that the end of the bell crank
lever h, and the notch e² are so inclined that after they come in contact
any further pressure on the bolt moves the stump out of contact with the
tumblers, so as to defeat any attempt which may be made to feel for the
gatings of the tumblers. In some tumbler locks the tumblers are mounted
on a stud or axis carried by the bolt, and the stump in such cases bas
heretofore usually been fixed to the lock plate, such locks as will readily
be understood from the description already given, together with the Drawings

page_text: which have been referred to may be arranged according to my Invention
by mounting the stump on a bell crank lever working in the same manner
as the lever h, shewn in the Drawings. The adaptation of my Invention
to locks in which slides are employed in place of tumblers will also be
readily understood without any detailed description, I however prefer the
arrangement shewn in the Drawings.
In witness whereof, I, the said George Hamilton, have hereunto set my
hand and seal, this Twenty-seventh day of April, in the year of our
Lord One thousand eight hundred and sixty-one.
GEORGE HAMILTON. (L.S.)