A Combined Lock and Safety Drop Latch.
Year: 1894

page_text: Date of Application, 22nd May, 1894-Accepted, 11th Aug.,
1894
COMPLETE SPECIFICATION.
A Combined Lock and Safety Drop Latch.
I, EDWARD COOK, of Barrington Place, Burwood Road, Hawthorne, in the
Colony of Victoria do hereby declare the nature of my invention for "A COMBINED
LOCK AND SAFETY DROP LATCH" and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
My invention relates to improvements in carriage locks and safety latches and
the object is to provide a safety latch to act as a guard, in the event of the ordinary
lock fastening being inadvertently released. The ordinary safety latch is controlled
by an attendant from the outside of the door, or the passenger by access through
the window.
The said safety drop latch may be introduced independently where an ordinary
lock is in use, and may be pivotted either to the outside of a slam jamb, to drop
over face of door, or upon inner face of door stile to drop over inner face of slam
jamb into a casing. In each or either case, a trench is provided on the edge of
lock stile or slam jamb as required, having an inclination or bevel equal to the rise
and fall of the drop latch, so as to admit of the latch entering and travelling on top
edge of said trench when door is pushed to, dropping over face when door is
closed.
The "lock" is used, in combination with the safety drop latch (hereinafter
described as "lock") under circumstances where no locks are in use, or where the
lock is considered preferable in combination with the latch. The details of which
I hereinafter more particularly describe.
Figure 1 is an elevation of the safety drop latch as applied to the outer face of
slam jamb, showing the inlet of incline trench as prepared for receipt of an inner
latch when applied.
Figure 2 is an elevation of the "lock" as applied to the stile of door showing the
inlet of incline trench as prepared for receipt of the outer safety latch.
Figure 3 is a plan of lock and latch as in operation.
Figure 4 is a vertical section showing internal workings of look and latch, and
supplementary latch and case.
Figure 5 is an elevation of lock stile showing striking plate, track, socket, the
inclined track of outer latch and the end view of the inner drop latch and case, as
used when the lock and latches are applied together.
66
Figure 6 is an elevation showing edge of a slam jamb with incline track for the
supplementary" inner latch its receiving case, and the outer latch with its casing,
as applied in combination with Figure 5.
Figure 7 is a slam jamb prepared to receive the drop latch when used without
the lock.
Throughout the several figures, similar letters of reference denote similar parts.
A is the "safety drop latch," secured to the end of a spindle A' and extending
through the casing A². A is a cam casting secured on to spindle A¹. A' is a
multiple feather spring for reciprocating the bolt. A is a reciprocating bolt
located in the casing A', operated by the spring A', and slope of striking plate A*,
its end A' is slotted to retain the multiple feather spring A, a projection a³ is
formed on said bolt as shown when the latch A is operated separately, this bolt
must have enough clearance in the casing face to allow the tail end to drop towards
a pin A, secured in case. Bis a supplementary latch pivotted and enclosed in a
casing B. B¹ is a crank for lifting the latch B and is secured to a spindle B
which extends through door, or frame, to opposite face connecting with a crank B³

page_text: which is pivotted to an operating rod B. A lever crank B' is fixed on to lock
handle C and pivotted to the said operating rod B actuating the latch B. C is
an inclined track or trench into which when closing the door the latch A enters,
and travels upwardly and drops clear of trench when door is shut. A similar
trench Ca is used either for operating the supplementary or an independent latch.
C³ is the riding plate of inclined track C. C is an ordinary handle fitted with a
spindle C3 bearing upon front plate C and back bearings C. The spindle C³ is
pivotted with a spiral spring C to detain, and cause a return motion to said
spindle C³. C³ also acts as a spindle to the cam C with its segmental cone shaped
face which when in position forms a sliding plate for bolt As when in the act of
closing, and is moved into the casing A2 by rotating the handle C clear of bolt A'
when in the act of opening. C is lifting crank attached to the handle C². D¹ is a
pawl which drops into niche Ch in the spindle C³ and is held in position by a
spring D for detaining the spindle C³ when door is opened and until the door is
closed, when it is released by contacting with A. The striking plate A® for the
safety drop latch" when said latch is used without the lock mechanism, may be
formed to suit the bevel on the edge of a door stile without any bolt slot whatever
and shaped to act as the riding plate of the inclined trench C.
Having described the principal parts contained in my invention, I now describe
the manner of operating the combined lock and latch mechanism ;-
The action of turning the handle C removes the cam casting C' out of the path
of bolt A, and admits of a clearance track for the said bolt and operates the
latches A & B.
In the closing of a door the cam casting 07, contacts with the bolt A5, and by
reason of projection a striking cam A³ the safety latch causes said latch A to fall
over face of door.
The bolt then enters the socket in case 9, and secures the door.
The striking plate A' as introduced in this combination is formed with an
inclined riding plate C and trench C as before described, with a horizontal slot g
on face C for bolt A'; and bolt track C. The door is secured by the outer
surface of cam C7 acting as a stop for the bolt A².
The striking plate for inner latch is as described for the independent latch. But
may prefer it fixed on the jamb of the frame instead of the door.
I now describe the manner of operating the safety latch when used without the
lock mechanism;―
The operation of the safety drop latch when acting independently of the lock is
as follows ;-
In the action of a door closing, the "striking plate" A in contacting with the
reciprocating bolt A causes it to recede in its socket; the projection a³ striking
the cam casting. A³ of the spindle A', thereby communicating a rotary motion to
the latch A causing it to fall over face of door. The bolt A³ terminates with a
slot A to retain the multiple feather spring A. The bolt A when forced into its
recess or slot in casing C by contacting with striking plate A compresses the
multiple feather spring A4 and remains in that position until released by the
operation of opening of the door.
The latch A can be returned to its "clear of door" position owing to the tail of
said bolt being forced down towards a check pin A secured in casing 'by reason of
the arm X of cam A³ pressing on the tail of the retracted bolt.
In the event of the latch A being inadvertently, placed in a way of obstructing
the closing of door, the inlet of the inclined trench C meets the latch A; the said
latch A then enters inlet and travels on inclined trench C and drops over face of
door, or stile, when the operation of closing is affected.
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 1
claim is;-
First. In a safety drop latch; a pivotted latch A, an enclosing case A², fixed on

page_text: either stile or jamb, as may be preferred, and meeting au inclined trench C, as a
means of operating the said latch to secure a door, as described and illustrated in
the drawings.
Second. In a safety drop latch; a holt A³ reciprocating in a socket between and
by means of a striking plate A and a spring A actuating a drop latch to rotate
and fall over the face of door and the means shown in the drawings, allowing the
latch to be returned clear of door space, substantially as described and illustrated
in the drawings.
Third. In combination with the bolt A' and the before mentioned' parts. The
bevelled striking plate A7 with its inclined trench C and its application for
removing the obstruction of a latch on jamb or door operating as a riding plate,
substantially as described and illustrated in the accompanying drawings.
Fourth. In combination with the safety drop latch with means to operate same.
A bolt receiving lock with its combined disappearing sliding face and bolt stop C7
its actuating and return action spindle C³ and means with which the said spindle is
retained and operated. The case (a) enclosing the several parts with its slotted
way for bolt A and disappearing sliding face C', the inclined trench (C),
substantially as before described and illustrated in the drawings,
Fifth. In combination with a bolt receiving lock. The crank and operating rod
and spindles actuating the lever drop latch on the inside of door operated by, or
independently of the said lock or bolt, and upon an inclined riding trench plate C¹
of trench C³, substantially as hereinbefore described and illustrated in the
drawings.
D..
A1 1004
W. B. ROWLINGSON,
Agent for Applicant.