Improvements in Locks and Latches.
Year: 1886

page_text: Date of Application, 12th Mar:, 1886.
Complete Left, 11th Dec., 1886.
Complete Accepted, 11th Jan., 1887.
PROVISIONAL SPECIFICATION.
Improvements in Locks and Latches.
I, FREDERICK JAMES BIGGS of Leadenhall Buildings, Gracechurch Street in the
City of London, Merchant do hereby declare the nature of this invention to be as
follows:-
My invention has reference to locks and latches in which the latch proper is capable
of being reversed by a swivelling or turning movement so as to adapt it as required
either to a right hand or left hand door. With these reversible latches some con-
trivance is necessary to keep the latch from turning when once properly adjusted and
for this purpose pins, catches and other like devices have been employed to take into
or against corresponding parts of the latch or bolt and thereby prevent axial move-
ment thereof.
Now according to my invention I dispense with the pins, catches or other like
devices and so construct the lock and fit the latch or bolt therein that the latch is
prevented from turning by means of the face or end plate of the lock, that is to say,—
that until the face or end plate is attached, the latch can be made to swivel or turn to
adapt it to either a right hand or left hand door, while when the face or end plate is
secured in place it prevents the latch from being turned.
I will describe my invention as applied to a mortise lock to which it is more
particularly applicable. I provide the lock with a fore plate as usual to enable it to be
screwed to the door and with a face plate as usual which when the fore plate is
properly secured is screwed thereto.
I make the aperture in the fore plate through which the latch passes of sufficient
size to allow the latch to be turned therein and I make the aperture for the latch in
the face plate too small to allow of the latch being turned therein. The aperture in
the fore plate is preferably circular and that in the face plate rectangular to correspond
with the sectional form of the latch but this is not essential so long as the first will
and the second will not allow the latch to be turned.
With this arrangement when the lock has been fitted to the door and the face plate
has been screwed thereto in the usual way the position of the latch can be reversed if
necessary before screwing on the face plate while after the face plate has been secured
in place the latch cannot be turned.

page_text: In the case of locks having a latch whose height or thickness from top to bottom is
greater than the width of the lock a hole in the fore plate for the latch proper to turn
in could not be made large enough. In this case (and in other cases when desired) I
so adjust the parts of the lock that when the locking plate is thrown forward by means
of a key or otherwise the latch proper is entirely beyond the fore plate and can there-
fore he turned when the face plate is not in place. In such cases it is desirable, but
not essential, that the disc or piece in which the neck of the latch turns and which
moves with the locking plate should occupy the latch aperture in the fore plate when
the locking plate is thrown forward.
Although specially intended for mortise locks my invention can also be applied to
other locks, such as rim locks for example; in this case a removable face plate would
be attached to the ordinary fore or front end plate of the lock case and would have an
aperture not large enough to allow the latch to turn therein while the fore or front
end plate would have a latch aperture large enough to permit the latch to turn; or as
an alternative the parts of the lock would be so adjusted as above explained that when
the locking plate is thrown forward the latch proper would be entirely beyond the
fore or front end plate and could therefore be turned until the face plate had been
put in place; or the ordinary fore or front end plate may be removable to allow the
latch to be reversed; the aperture in this plate preventing the latch turning when the
said plate is fixed to the lock case.
J. C. MEWBURN,
169, Fleet Street, London,
Agent.

page_text: I FREDERICK JAMES BIGGS, of Leadenhall Buildings, Gracechurch Street, in the
City of London, Merchant, 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 :-
My invention has reference to locks and latches in which the latch proper is capable
of being reversed by a swivelling or turning movement so as to adapt it as required
either to a right hand or left hand door. With these reversible latches some con-
trivance is necessary to keep the latch from turning when once properly adjusted and
for this purpose pins, catches and other like devices have been employed to take into
or against corresponding parts of the latch or bolt and thereby prevent axial move-
ment thereof.
Now according to my invention no pins, catches or other like devices are employed
for the purpose, but I so construct the lock and fit the latch therein that the latch is
prevented from turning solely by means of the face or end plate of the lock, that is
to say, that until the face or end plate is attached the latch can be made to swivel or
turn to adapt it to either a right hand or left hand door, while when the face or end
plate is secured in place it prevents the latch from being turned.
I will describe my invention as applied to a mortise lock for which it is more
particularly intended.
Figure 1 is a side elevation of the lock with the front half of the case removed and
with the fore plate and the face plate in section; Figure 2 is a front elevation of the
lock with the face plate removed and Figure 3 a front elevation of the face plate.
The lock shown is a tubular lock but the invention is equally applicable to mortise
locks of other form. a is the lock frame, the fore plate which is cast with or per-
manently fixed to one half of the frame a, c is the face plate and d the latch one side
The latch d
of its front portion being bevelled or inclined in the ordinary manner.
when not held by the face plate as hereinafter described is free to be turned on its
axis for which purpose its inner end is formed with a pin that passes through a piece e
and through a washer fand is then flattened out to retain it in place. The piece e
forms part of the bolt g. This mode of mounting the latch so that it can be turned
on its axis is not of itself novel.
With this
The invention consists in so constructing the face plate c and the fore plate that
when the face plate c is in place the latch d cannot be turned while on the other hand
when the face plate is removed the latch d can be turned so as to be changed from a
latch for a right hand door to a latch for a left hand door or vice versa.
object the aperture in the fore plate through which the latch passes is made
sufficiently large to allow of the latch & being turned on its axis therein while on the
other hand the corresponding aperture in the face plate c is not large enough to
allow of the latch being turned therein. The aperture h is preferably circular and
the aperture rectangular (to correspond with the sectional form of the latch) as
shown, but this is not essential so long as the first will and the second will not allow
the latch to be turned.

page_text: With this arrangement when the lock has been fitted to the door and the fore plate b
has been screwed thereto in the usual way the position of the latch can be reversed if
necessary before screwing on the face plate while after the face plate has been
screwed in place the latch cannot be turned.
The stop which limits the inward travel of the bolt g with the latch d should be so
placed as to prevent the latch in its inward travel passing quite beyond the face plate c
as if it did so it would be liable to move slightly on its axis and would not be able to
return. The lock mechanism may be of any ordinary character.
In the case of locks having a latch whose height or thickness from top to bottom is
greater than the width of the lock, a hole in the fore plate for the latch to turn in
could not be made large enough. In this case and in other cases when desired I so
adjust the play of the locking plate that when thrown forward by means of a key or
otherwise the latch proper dis entirely beyond the fore plate band can therefore be
turned when the face plate e is not in place. In this case it is desirable that the disc
or piece e should occupy the aperture in the fore plate when the locking plate is
thrown forward.
Although specially intended for mortise locks my invention can also be applied to
other locks such as rim locks for example; in this case a removable face plate would be
attached to the ordinary fore or front end plate of the lock case and would have an
aperture not large enough to allow the latch to turn therein while the fore or front
end plate would have a latch aperture large enough to permit the latch to turn; or as
above described the play of the locking plate would be so adjusted that when thrown
forward the latch proper would be entirely beyond the fore or front end plate and
could therefore be turned until the face plate was put in place.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed I declare that what I claim in respect
of locks and latches is :-
1. The combination of a swivelling latch and a removable face plate said latch being
capable of being reversed when said plate is detached from the fore or front end plate
but prevented by said face plate from reversing when the latter is in position,
substantially as herein described.
2. The combination with the swivelling latch d of the fore plate having a latch
aperture large enough to allow the latch to turn and of the face plate c having a latch
aperture not large enough to allow the latch to turn, substantially as and for the
purpose herein described.
J. C. MEWBURN,
169, Fleet Street, London,
Agent.