Improvements in and Connected with Mortice Locks and Latches.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in and Connected with Mortice Locks and Latches.
I, WILLIAM STURMEY, of Crown Works, Clemson Street, Willenhall, Staffordshire,
Lock Manufacturer, 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 :—
This invention has reference to those mortice locks and latches in which the latch
bolt is made with an incline on each side so that the lock or latch can be used for
either a right hand or a left hand door without altering any of the mechanism of the
lock or latch. Heretofore the objection to mortice locks and latches constructed in
this way has been that when the door is closed it is liable to be opened again by very
slight pressure such as by the pressure of the wind as it is only maintained closed by
one of the inclined sides of the bolt being in contact with the striking plate which
defect it is the object of this invention to overcome.
In carrying out this invention I provide in each inclined side of the latch bolt a
flat recess or fat recesses and a corresponding flat projecting part or parts on the hole
in the striking plate with which the latch bolt engages so that when the door is closed
the flat recess or recesses at one side of the latch bolt will come into contact with the
corresponding flat projecting part or parts on the striking plate and thus prevent the
door being opened by any pressure from without as such pressure will now have no
tendency to force the latch bolt back.
My invention is illustrated by the accompanying drawing on which Fig. 1 is a
general view of a mortice lock provided with a latch bolt constructed according to
this invention, and Fig. 2 represents the striking plate for the same; Fig. 3 represents
the end of the latch bolt of the same separately; Fig. 4 represents the front plate of
the said mortice lock separately; Fig. 5 shews how the latch is forced back by the
striking plate in the usual way in closing the door, and Fig. 6 shows how my improved
latch bolt and striking plate prevent the door being opened by a pressure in the
lirection of the arrow without first turning the knob to withdraw the latch bolt;
Figs. 7 and 8 illustrate a modification of my invention for use with a swinging door
which opens either by pulling or pushing and Fig. 9 is a general view of the end of
the latch bolt of the same on an enlarged scale.
The same letters of reference indicate the same or corresponding parts in all the
figures of the drawing.
Referring firstly more particularly to Figs. 1, 2, 3, 4, 5 and 6, a is the mortice lock
or latch casing which may be of any usual form and is the striking plate for the
same. c is the double inclined latch bolt in which I provide the flat recesses d¹³,
one at either side of the latch bolt, thus leaving an inclined part e¹ above and below
the flat recess d', and a similar inclined part above and below the flat recess d².
The striking plate b is of usual form except that in the latch bolt hole it has the
projecting part y corresponding with the recesses d'. This projecting part g is made
rather longer than the depth of the recesses d' d² so as to bear against the back of
one or other of the said recesses and prevent the inclined parts of that side of the
latch bolt touching the striking plate.
When the door to which the said mortice lock or latch is fixed is being closed,
(see Fig. 5) the latch bolt c is forced backwardly in the usual manner by its inclined
side e coming into contact with the striking plate b; but when the door is closed
and the latch bolt c has shot forward into the hole, as shewn by Fig. 6, the door
cannot be opened by a pressure in the direction of the arrow as the back of the flat
recess d¹ will come into contact with the front flat edge g₁ of the projecting part
and as this part is flat there is no tendency to force back the latch bolt.
before stated the projecting party is made long enough to prevent the inclines e'
touching the striking plate.
As

page_text: When the said lock or latch is fixed to a door of the opposite hand, the striking
plate b has to be turned half round so as to bring its back to the front as is usually
done; the inclined parts e¹ will then come into contact with the striking plate in
closing the door so as to force the latch bolt backwardly and when the door is closed
the back of the flat recess d² will come into contact with the front flat edge gl of the
projecting part g and prevent the bolt being pushed back by a pressure on the door
as above described. The hole in the front plate of the lock or latch through which
the latch bolt projects is, as shewn by Fig. 4, preferably made of the same shape as is
the latch bolt in cross section.
The form of the end of the latch bolt and corresponding shape of the hole in the
front plate of the lock or latch and the shape of the hole in the catch plate illustrated
by Figs. 1, 2, 3, 4, 5 and 6, are what I consider to work best in practice, but it will
be evident that the number of the flat recesses in the inclines and corresponding pro-
jecting part in the catch plate can be increased without departing from the nature of
my invention. For instance the latch bolt may be of the form represented by Figs. 7
and 9 which has two recesses d' d in the incline at one side and two corresponding
recesses d² ² in the incline at the other side, the latch bolt hole f in the striking plate
being made with inwardly projecting parts as shewn by Fig. 8 to correspond with
these recesses.
When using my improved latch bolts in locks or latches for swinging doors which
open either by pushing or pulling, the catch plate requires to have a striking part at
cach side as is usual (see Fig. 8) and the latch bolt hole f is provided with a pro-
jecting part or parts y at each side corresponding with the recess or recesses at each
inclined side of the latch holt.
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 :-
The improvements in those mortice locks and latches which have a latch bolt
provided with a double inclined front, and in the striking plates for the same, for
preventing the door to which the lock or latch is fixed being opened without first
withdrawing the latch bolt from the striking plate hereinbefore described and
illustrated in the accompanying drawing; that is to say, providing a recess or
recesses in each of the inclined sides of the front of the bolt, so as to leave an
inclined part above and an inclined part below each of the said recesses, and a corre-
sponding internal projection or projections in the latch bolt hole in the striking
plate, to engage with the said recess or recesses in the latch bolt when the door
is closed, for the purpose and substantially as hereinbefore described and illustrated.
Dated this 30th day of September 1889.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.