Improvements in or connected with Latch Locks.
Year: 1896

page_text: Date of Application, 23rd Apr., 1896-Accepted, 23rd May, 1896
COMPLETE SPECIFICATION.
Improvements in or connected with Latch Locks.
I, EDMUND PARKINSON O'KELLY of 44, Saint Thomas's Terrace South
Circular Road, Dublin, Ireland, Accountant, 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 refers to a new or improved construction combination, or arrange-
ment of parts, composing latch locks as hereafter described, and whereby the
action is improved, while such locks are rendered more compact and securo than
heretofore.
In order that my invention may he readily understood, I will fully describe the
same by reference to the accompanying drawings.
Figure 1 is an elevation of my improved lock, the back plate having been
removed in order to shew the working parts,
Figure 2 is a vertical cross section on the line X Y of Figure 1,
Figure 3 is an elevation of the lock as seen upon the inner side of the door or
other place to which it is or may be applied.
Fig. 4 is a horizontal section through line X Y Fig. 1, shewing the lock
applied, and also shewing the formation of the acting end of the bolt.
Figure 5 is a diagram shewing the mode of delineating the acting end of the
bolt,
Figs. 6 are views of the levers or tumblers detached.
Figure 7 is an elevation of the key, and Fig. 8 is a view of a part detached,
hereafter mentioned.
Similar letters of reference refer to like parts in the several figures of the
drawing.
According to my invention I arrange within the case A the bolt B, the rear
thickened part of the latter being acted upon by the bolt spring C, and this rear
part is extended downwards at B. The bolt B is connected with an internally
projecting handle D, Figure 2, the stem by which the latter is carried being formed
with the bolt, and projecting through a lengthway slot D', Fig. 3, in the interior
face of the case A, the slot being covered by the bolt B; the projecting end of
the bolt may thus be withdrawn within the case by the handle D. This projecting
or acting end of the bolt has the contact surface thereof commonly rounded or
inclined, but according to my invention, it is formed with a greater and a lesser
curved surface, B' and B', so that the first contact with the rounded edge E¹ of
the post plate E, Figs. 1 and 4, on closing the door, is received by the larger
curve B, which as it were starts the bult B in its backward travel, tho finish of
the back travel of the bolt being effected by the smaller curve B'. By this
construction the force necessary to close the door is divided, and a secure and easy
closure is obtained.
I have found it convenient, in order to obtain a suitable proportion, between the
two curves of the acting portion of the bolt, to forin same as shewn by the diagram.
Figure 5. The length a band the thickness bd of the projecting portion thereof
being equal, bisect the thickness at e and make be equal to be. With c as centre
and radius c d describe the segment fd to produce the curve B' and with fas
centre and radius a describe the smaller segment a g to produce the smaller
curve B'.
Above the bolt B I provide a finger catch F having a stem, (preferably square).

page_text: passing through a vertical slot F in the case A, Fig. 3, and fitted with a a globe
shaped nut or knob F. The catch F when lowered takes into one of two
notches B B in the bolt and retains it in either position, and on the stem of the
catch is located a bent spring F, which being moved with the catch, produces
the required stiffness of action.
Below the bolt B, but otherwise clear of same, I locate what I term a repeller G
(shewn detached at Figure 8) guided laterally and retained in position by
screws GG' Fig. 3, passing through slots in the case as shewn and screwed into the
repeller G Fig. 1; the upper part of the repeller at (+ comes in front of the down-
ward extension B' of the bolt B before mentioned, while the repeller is formed
with a lower curved part G' against which the key acts to force back the repeller
and thereby the bolt B. G is a square stud fixed to and projecting from the
repeller to co-act with the levers as hereafter described.
The levers are pivotted below the repeller G on a screw H and are four in number,
two similar to H Figure 6. and two similar. to H', these pairs of levers being
separated by what I call a suspended ward J Figure 6. The screw H is threaded
into a thickened part H of the frame. The levers II Hare, as shewn, formed
with a loop H to receive the stud G' and the entrance to the loop is guarded by
upper and lower teeth so that should any other key not adjusted to the particular
lock, be used, it must be able to pass the suspended central ward J and also it must
lift the levers exactly the required height simultaneously, and if the latter or one
of them is or are lifted slightly more the lock is inoperative. H' Fig. 1 indicates
the position of the lever springs (one for each lever), the tail ends of such springs
bearing against a stud or pivot li, fixed at one end to or formed with the frame A
and which passes through a slot in the repeller G.
Below the levers is the keyway from the exterior of the door, its passage way
into the lock being strengthened by a thickened part K Fig. 2; the key passes
into an interior socket L of quadrant shape (Fig. 1) and formed with three.
circumferential steps or wards. The socket and wards should be formed of iron
or hard metal and be fixed securely to the lock case A, and finished externally with,
say a globe shaped nut, which while covering the fastening of the part L prevente
the key passing entirely through the lock plate.
With a lock thus constructed it is necessary that the key should be so formed
that it will raise 4 levere to an exact height; that it shall be able to pass a
stationary ward J, be of proper length to throw back the repeller G, and must also
fit the circular steps or wards of the key socket L. I say that an instrument that
will effect all these requirements to open the lock must be the key itself or a
duplicate.
A key suitable to the lock shewn is illustrated at Figure 7, and the parts of the
key are marked with letters corresponding to the lock parts acted on thereby; the
handle form preferably as shewn to obtain an increased loverage.
The post plate E is flush with the case A and is preferably formed with a rounded
edge E Fig. 4, so that when the door opens there is a framed slot visible, the post
plate being in keeping with. the lock, but of course it could be made plane, or in
accordance with the purpose with which the lock is to be used.
By the combination and formation of the parts as herein before described, and
according to my invention, I obtain a lock which is incapable of being unlocked
without the proper key or a duplicate thereof, and I am enabled to obtain a closer
combination of the parts than heretofore, and to produce a more compact lock
while the peculiar configuration of the bolt end produces a more elastic and secure
closure.
Having now particularly described and ascertained the nature of my inven
tion, and in what manner the same is to be performed, I declare that what I
claim, as my improvements in or connected with latch locke, is as follows.
1. The laterally sliding bolt B, having the projecting or acting end thereof
formed with greater and lesser curved surfaces B B, whereby the bolt is forced

page_text: back by impact with the opposed socket or post plate, first by the curve of larger
radius, and lastly by the curve of lesser radius all substantially as described and
shown with reference to Figures 1. 4 and 5 of the accompanying drawings.
2. The bolt B arranged to slide laterally in the case A, an operating handle for
the bolt, and the curved contact surfaces formed on the acting end of the said bolt,
in combination with the vertically adjustable finger catch F to fix the bolt in
either of two positions, an operating handle for same and the spring F¹ moving
with the catch to produce stiffness of action in the latter substantially as described
and illustrated with reference to the accompanying drawings.
3. The bolt B, and its co-acting parts, in combination with the repeller G, the
levers H H H H', the ward J and the key socket L, together with a corre-
sponding key (Fig. 7), all arranged and acting substantially as described and
illustrated with reference to the accompanying drawings.
4. The general arrangement and construction of parts composing my improved
latch lock substantially as described and illustrated with reference to the accom-
panying drawings.
02-11 £ 1000
BREWER & SON,
London and Leeds, Agents for the Applicant.
BREWER & SON,
London and Leeds, Agents for the Applicant.