IMPROVEMENTS IN LOORS
Year: 1880

page_text: LETTERS PATENT to Horatio Kelson Bromhead, of Glasgow, in the County of
Lanark, North Britain, Architect, for an Invention of "IMPROVEMENTS IN
LOORS"
PROVISIONAL SPECIFICATION left by the said Horatio Kelson Bromhead
at the Office of the Commissioners of Patents on the 15th October 1880.
HORATIO KELSON BROMHEAD, of Glasgow, in the County of Lanark, North
Britain, Architect. "IMPROVEMENTS IN LOCKS."
This Invention, which relates to improvements in locks, has reference more especially
to that class of locks commonly known as Mortise locks, and which are used for the
doors placed in houses and other buildings, and it has for its object more especially
to dispense with the use of springs for acting upon and retaining the latches and
bolts of the said locks in the locked or unlocked position. At the same time it is to
be understood that the said Invention may also be applied to locks which are not
necessarily Mortise locks, but are fixed to the outer part or sides of doors.
In carrying the Invention into practice the horizontal bar forming the latch of
the lock is attached to the upper end of a weighted lever whose lower end is
centred towards the lower innermost corner of the lock casing, or the weighted
lever may be centred at a higher point within the lock casing. A double armed
follower through which the handle for operating the latch passes is arranged so that
the under part of the weighted lever shall rest upon the straight surface formed by
the upper side of the two arms of the follower. The follower is provided with two
arms for the purpose of enabling the weight to be lifted and the latch drawn in by
turning the handle for operating them either in the right hand or left hand
direction.
For the purpose of securing the bolt either in an open or in a closed position
a weighted tumbler is provided which by its downward tendency engages with the
recesses or projections made in the bolt for that purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Horatio Kelson Bromhead in the Great Seal Patent Office on the
1st April 1881.
HORATIO KELSON BROMHEAD, of Glasgow, in the County of Lanark, North
Britain, Architect. "IMPROVEMENTS IN LOCKS.",
My said Invention consists in the following arrangements or combinations of
parts constituting improved locks wherein springs for retaining the latches in their
shot position, and the tumblers in the position to secure the key bolt in its shot,
or in its withdrawn position, are dispensed with.
Figure 1 of the accompanying Drawings represents in elevation, with the front
plate removed, a lock constructed according to my Invention, with the latch in its
shot position, and with the key bolt in its withdrawn or unlocked position;
Figure 2 is a similar view, but shewing the latch withdrawn and the tumbler of
the key bolt raised by the key preparatory to shooting or locking the bolt; Figure 3
is also a similar view, but shewing the latch withdrawn by turning the knob in
the reverse direction to that in which it was turned to withdraw the latch, as in
Figure 2; Figure 3 also shows the key bolt shot forward or in its locked position;
Figure 4 represents a modification wherein the follower or lever to act upon the
weight to withdraw the latch is dispensed with, and Figure 5 represents another
modification wherein the latch is situated at a lower part of the lock. Corre-
sponding parts are marked with like letters of reference in all the Figures.
Referring to Figures 1, 2, and 3 the casing of the lock is marked A. The
horizontal bar B forming the latch of the lock is connected to the weighted lever C
by a pin b, the said weighted lever turning upon a stud c fixed to the lock casing.
The double armed follower D is fixed upon the spindle d which carries the knobs.
The said follower D is arranged so that when the latch is in its shot or thrown
out position the under part of the weighted lever C rests upon the upper surface
of the follower. The follower D is provided with two arms, as shewn, so that the
weight C may be lifted by either the one or the other arm, and the latch drawn
in whichever way the knobs may be turned. Figures 2 and 3 respectively exhibit
the parts in the positions they assume when the latch has been withdrawn by
partially rotating the knob towards the right hand and towards the left hand.
By reference to these Figures it will be seen that when the knob is operated one
or other of the arms of the follower D acts upon the underside of the weight C and
causes it to turn upon its centre c and pull the latch B back. On releasing the
knob the weight C falls until it rests upon the follower, as seen in Figure 1, and
the latch B is, by the falling of the weight C, shot or thrown forward.
The bolt E is retained in its shot or locked position and in its withdrawn or
unlocked position by means of a weighted tnmbler F mounted upon a stud at f
This tumbler is without a spring, it being of such weight at its outer end that
the said end falls into the position, Figures 1 and 3, and remains in that position
until acted upon by the key. A projection f on this tumbler engages when the
bolt is withdrawn in a recess or notch e in the bolt E. When the key is partially
turned in the lock it raises the tumbler F into the position, Figure 2, when the
Blot in the bolt allows the said bolt to be shot forward by the key, the projection f
then falling into the recess e¹ in the bolt, as shewn in Figure 3.
In the modification, Figure 4, the follower D is dispensed with, and the spindle d
of the knobs passes through the weight C as its fulcrum, and so that when it is
turned in one direction it will raise the said weight C and withdraw the latch
bolt B. In Figure 5 the latch bolt B is shewn arranged beneath the key bolt E,
the weight C having its fulcrum at c, and being attached to the latch bolt B at b.
In Figure 6 is shewn a modified form in which the weight C is attached to the

page_text: end of the bell crank lever C2 turning on the fixed stud at c, and connected to the
latch bolt at b. The operation in all these arrangements is essentially similar to
that explained with regard to Figures 1, 2, and 3.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in or under which the same is or
may be used or practically carried into effect, I would observe in conclusion that I
wish it to be understood that I do not claim simply and by itself the substitution
of weights for springs in locks, but what I consider to be novel and original, and
therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is,
First. The combination of the latch bolt B and weight C with the follower D,
so arranged that when the latch-bolt B is in its normal or shot position the under-
side of the weight C rests against the follower D, essentially as herein before
described and illustrated in Figures 1, 2, 3 and 5 of the accompanying Drawings.
Secondly. The modification described with reference to and illustrated in
Figure 4 of the accompanying Drawing, wherein the spindle d passes through the
weight C and acts directly thereupon in withdrawing the latch, so that the use of
a follower is dispensed with.
Thirdly. The general arrangement and combination of parts constituting the
lock illustrated in Figures 1, 2, and 3 of the accompanying Drawings.
Fourthly. The general arrangement and combination of parts constituting the
lock illustrated in Figure 4 of the accompanying Drawings.
Fifthly. The general arrangement and combination of parts constituting the lock
illustrated in Figure 5 of the accompanying Drawings.
Sixthly. The general arrangement and combination of parts constituting the
lock illustrated in Figure 6 of the accompanying Drawings.
In witness whereof, I, the said Horatio Kelson Bromhead, have hereunto set
my hand and seal, this Seventeenth day of February, in the year of our
Lord One thousand eight hundred and eighty one.
T
HORATIO K. BROMHEAD. (L.S.)