Improvements in the Construction of Emergency Bolts and Latches.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Construction of Emergency Bolts and
Latches.
I, ALFRED WATSON of 6, Maidstone Street, Bradford, in the County of York,
Engineer do hereby declare the nature of this invention to be as follows:-
:
This invention, relates to certain improvements in emergency bolts and latches,
and has for its object, the arrangement and construction of the same in such a
manner that, on pressure being applied to the knob or bar of the bolt or latch,
the bolt of the same is operated in the direction, that, the door or doors are
liberated, and allowed to fly open without the aid of a key; and to so arrange the
internal parts of the latch that, the bolt cannot be moved by applying external
pressure to the same, and thereby to make the latch unpickable by the insertion
of an instrument from outside the door.
1
A knob or bar is fixed on
I accomplish my object in the following manner.
the inside of the door or doors and is attached to a sliding block which passes
through a latch case, and is connected by a pin or the like, working preferably
in a slot formed in an arm projecting from a bar mounted in the latch case in a
manner, that it can be moved on its axis.
In this bar a spiral cam groove is formed, the edges of the groove are cut
at right angles to the axis of the bar, and mounted in the cam groove is a pin,
projecting from a lever pivotted at one end to the iatch case, the opposite end
of the lever engaging with some portion of the latch bolt so that, when the knob
or bar is pushed, towards the door, the cam is moved on its axis and the bolt
withdrawn from the striking plate.
On closing the door, when the knob or bar is pulled in the direction towards
the interior of the room, the bolt is shot into the striking plate and the door
secured.
By extending the length of the cam bar, two spiral cam grooves may be cut,
and two bolts operated, say one to engage with a striking plate in the door head,
and one in the floor, the bolts being withdrawn from their respective striking
plates on applying pressure to the knob or bar, by which the cam bar is operated
and the bolts withdrawn in the manner as before described.

page_text: Improvements in the Construction of Emergency Bolts and
Latches.
I, ALFRED WATSON, of 6, Maidstone Street, Bradford, in the County of York,
Engineer, 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 certain improvements in emergency bolts and latches,
and has for its object, the arrangement and construction of the same in such a
manner that, on pressure being, applied to the knob or bar of the bolt or latch,
the bolt of the same is operated in the direction, that the door or doors are
liberated and allowed to fly open, without the bolt or latch having to be operated
by the turning of a handle or by aid of a key; and to so arrange the internal 1
parts of the bolt or latch that, the protruding latch bolt cannot be moved on the
application of external pressure.
In describing my invention in detail, reference is made to the accompanying
drawings, in which Fig. 1 represents an elevation of a pair of folding doors
provided with my improved bolt or latch, each door is fitted with a cross bar for
operating the same.
Fig. 2 is a similar elevation of a pair of folding doors, each fitted with my
improved bolt or latch in a manner for liberating each door independently
of the other.
Fig. 3 represents the elevation of a single door with the protruding latch bolt :
arranged to engage with a striking plate secured to, the door casing.
The remainder of the figures are detached details hereinafter referred to, similar
parts are indicated by similar letters where they appear.
In Fig. 1 the bolt or latch casing A. is fixed to the inside of the door B, a
sliding knob C. projecting from same as shown by sectional detail Fig. 5.
Engaging with knob C. is a bar D. supported at the opposite end by another
knob C
The shank E. of the sliding knob C. is arranged with a slot hole F. shown by
detail Fig. 4 representing the internal parts of the improved bolt or latch;
with this slot hole engages an arm G. projecting from a rocking bar H. mounted
on an axle passing through the centre of said bar, and supported by the lock
or latch case A. in a manner that the rocking bar H. may move on the axle.
In the rocking bar H. two short spiral or cam grooves K. K. are cut, the edges
of the grooves projecting towards and by preference at right angles to the axis
of the said bar, and mounted in each cam groove K. is a pin L. in one groove
and L¹ in the other, the pins projecting from the respective levers M. and M¹
pivotted at one end N. to the bolt or latch case A, the opposite end of the levers
engaging with the respective bolts O. and O¹ so that, when the sliding knob C.
and bar D. are pushed towards the door B. the rocking bar H. is moved on its
axis, and by the cam grooves K. K. engaging with the pins L. and L' and the
before mentioned levers in the manner described; the bolts 0. and O' are with-
drawn from the striking plates fixed in the floor at bottom and frame at top of
door, thereby liberating the doors.
:
The door B is provided with two knobs C and C³ the former is sliding and
shown by sectional detail Fig. 6, in the socket P. of which is placed a compressed
spiral spring Q. for keeping the sliding knob Ca pressed butwards. A bar D¹
extending across the door B is supported by the knobs C and C³ the ends of
the bars D., and D' at the opening of the two doors in the centre are cut at an

page_text: angle as shown by detail Fig. 7, so that, should pressure be brought against the
bar D¹. the bar D. and sliding knob C. will be operated also, and the bolts O.
and 0 liberated in the manner as before described.
The knobs C¹ and C3 are both secured to the doors in a suitable manner and
bored for the reception of the respective bars D. and D' slightly larger than
the diameter of the said bars so as to allow the necessary movement of the bars
in the knobs when they are pressed toward the doors B. or,B¹.
On closing the doors B. and B' and when they are in the position for locking,
by pulling the sliding knob C. and bar D. towards the interior of the room, the
bolts O. and O¹ are shot into the respective striking plates and the doors
secured.
The doors B and B in Fig. 2 are each fitted with a lock or latch, and each
door opened independently of the other on applying pressure to the respective
bars D3. or D¹.
In Fig. 3 the door is fitted with a bolt or latch arranged for a sliding block or
bolt to engage with a striking plate fixed to the door frame, details of the bolt
or latch are shown by back elevation Fig. 8 and section elevation Fig. 9. In
this arrangement the sliding knob C. is shown pushed close to the bolt or latch
frame A, the shank E. of the knob has a slot hole F. cut therein as before described,
and is shown by the back elevation Fig. 8. Engaging with the slot hole is an
arm G. projecting from rocking bar H. mounted on the axle passing through the
centre of same and supported by the latch frame A, the rocking bar H. having
a spiral or cam groove K. cut therein, with which engages a pin L. secured to
lever M. pivotted at one end N. to the latch frame A. and to the other end of
lever is pivotted a sliding block or bolt R. which may be provided with a small
anti-friction pulley S.
On operating the sliding knob C. the bar D. the rocking bar H. and lever M.
are actuated in the manner as hereinbefore described, causing the sliding block
or bolt R. to be liberated from, or made to engage with the striking plate as may
be required, in accordance with the direction in which the said knob and bar
are actuated.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. A bolt or latch frame A. in which is mounted a rocking bar H. having spiral
or cam grooves K. cut therein, engaging with one or more levers connected to a
sliding bolt or bolts arranged and operated substantially in the manner and for
the purpose as hereinbefore set forth.
2. A bolt or latch frame in which is mounted a rocking bar H. having a spiral
or cam groove K. cut therein engaging with a lever M. connected to a sliding
block or bolt R, all arranged substantially in the manner and for the purpose as
hereinbefore set forth.