Improvements in Locks and Latches.
Year: 1891

page_text: Date of Application, 22nd Jan., 1891
Complete Specification Left, 22nd Oct., 1891-Accepted, 19th Dec., 1891.
PROVISIONAL SPECIFICATION.
Improvements in Locks and Latches.
We, HUGH DONALD FITZPATRICK of 70 Wellington Street, Glasgow,
Patent Agent and PETER KENNEDY of 4 Frederick Lane, Glasgow, Mechanic,
do hereby declare the nature of this invention to be as follows:-
This invention relates to street and other door locks and latches and it has for its
object to make said locks and latches unpickable. The invention is specially
adapted to locks such as Chubb's" having a number of bolts or tumblers.
The invention consists in fitting to the box or frame of the lock a lever pre-
ferably pivotted at its upper end. At a suitable distance from the pivot there is
fitted or made on the lever a projection or stud or equivalent.
This stud or
equivalent, when the bolts or tumblers are to be locked, bears on the upper side of
one or more of the said bolts or tumblers which is or are suitably cut out for its
reception. The lever which is of sufficient length to be caught by one of the bits
of the key is held in position by a spring.
When it is desired to have the lock so as to be freely locked and unlocked, the
pivoted lever may be pushed to the one side, against the action of the spring, by
means of a small lever or projection worked by a handle or knob on the inside of
the lock or a handle may be fitted on the pivot and a pin pushed through a hole so
as to lock or hold the lever in position when turned by the handle.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.
.
. COMPLETE SPECIFICATION.
Improvements in Locks and Latches.
We, HUGH DONALD FITZPATRICK, of 70 Wellington Street, Glasgow, Patent
Agent, and PETER KENNEDY now of 15 Caithness Street, Glasgow, Mechanic,
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 relates to street and other door locks and latches and it has for
its object to make said locks and latches unpickable. The invention is specially
or tumbling
adapted to locks such as "Chubb's" having a number of "tumblers
levers, or locks having combined bolt or bolts and "tumblers."
The invention consists in fitting to the box or frame of the lock an ordinary
sliding bolt or a common form of lever which latter may be pivotted at its
upper end. At a suitable distance from the pivot or, if a sliding bolt is used, the
guide pin there is fitted or made on the lever or bolt as the case may be a projection
or stud or equivalent. This stud or equivalent, when the locking tumblers are to
be locked, bears on the upper side of one or more of the said tumblers which is or
are suitably cut out for its, reception. The lever or bolt which is made with a
projection of sufficient length to be caught by one of the bits of the key is held in
position by a spring.
If desired in locking and unlocking the lock the sliding bolt or the pivotted lever,
as the case may be, may be pushed to the one side, against the action of the spring,
by means of a small lever or projection worked by a handle or knob on the inside
of the lock.
We have found in practice that it is better to use a sliding bolt or main lever
with our invention instead of a pivotted lever.

page_text: And in order that our said mvention may be properly understood, we have here-
unto appended an explanatory sheet of drawings whereon:-
Fig. 1 shows by way of example the interior.of a door latch with the levers
removed. It is of the construction commonly known as a "combination latch."
The latch is shown as locked.
Fig. 2 is a similar view to Fig. 1but the latch is unlocked.
Fig. 3 shows a modification.
Fig. 4 is the boss head for theilock.
Referring to Figs. 1.and 2.of the drawings:-
Ais the main lever or bolt. B represents in dotted lines the tumbling levers.
C is the handle stump. D is a guard. E is the hole for the key. Fis the pin on
which the tumbling levers, are fulcrumed. G is a spring bearing against the 'back
of the main lever or bolt A. H is a guide,pin projecting up through the guide slot 'I
of the main lever or bolt. Jis.a bearing or flange for the spring G to bear against.
Krepresent the springs of the tumbling levers. 'L is a raised and outwardly
tapering part on the end of the bolt. Mis the cover plate: of the 'latch frame.
N is the bit on the lower part of the bolt A for the key to catch on. P is a
projecting stud or pin on the main lever or bolt which lies on top of the tumbling
'levers B.
It will be seen at Fig. 1 that when the main lever or 'bolt is thrown or locked
the stud P rests on top of the straight part of the tumbling levers and prevents any
of them being lifted.or raised until the main lever or bolt is thrown back by the
action of the key on the bit N compressing the spring G. Immediately this is
done the key can be turned round and the tumbling levers 'lifted as 'the cut out
part B of the levers will then be under the stud.or stump 'P. 'This position is
shown at Fig. 2. The end of the main levertortbolt.istcut out.at.Qisoithat it can
pass the pin F.
If the lock is to be unlocked by the handle C the bevelled edges of the underside
of the bolt and of the plate on the handle catch against one another and the bolt
is easily thrown back against the action of the springtG.
When the door is to be locked by merely drawing it to, the bevelled or tapered
part L first catches the correspondingly tapered or bevelled part L' of the boss
head (see Fig. 4) and pushes back the bolt A 'before 'the levers are lifted by the
part L of the boss head. This is necessary as otherwise the tumbling levers
.could not.rise being held down by the stud or pin P.
In Fig. 3 the latch is shown with a downwardly projecting lever R-separate
from the main lever or bolt. This lever has the pin P on it which pin, also, in 'this
case bears against the part A' of the bolt. The lever is centred at S.and this
centre has a small handle, shown dotted, on it. This handle is at the inside of the
lock. "The small spring T may or may not be used as desired it is merely to keep
the lever R vertical. With this arrangement so long as the lever is vertical even
though the bolts may be shot back the levers.cannot rise. The levers can only be
turned by the key acting on the bit of the lever or by turning the handle of
the lever on the inside so that it affords an extra security for the lock.
With the improved lock it cannot be easily picked like the present combinations
with a piece of wire, etc., for 'as soon as the bolt may be thrown back by:a piece of
wire 'it must be retained there whilst the tumbling levers are being lifted otherwise
the bolt springs back again and locks both itself and the levers. With the present
combination latches when the bolt is thrown back it remains there giving mo further
trouble.
Having now particularly described and ascertained the nature of our said 'inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. Alatch or lock constructed with ta spring bolt or lever:(A) substantially as
and for the purpose set forth.

page_text: 5
2. A lock or latch having a spring lever or bolt A with a cross stud P, sub-
stantially as and for the purpose set forth.
3. The modified arrangement of lock substantially as hereinbefore described
with reference to Fig. 3 of the annexed drawings.
Dated this 21st day of October 1891.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.