MENTS IN FASTENINGS FOR DOORS ول "IMPROVE
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Alexander Arnott at the Office of the
Commissioners of Patents on the 27th January 1883.
ALEXANDER ARNOTT, of Wandsworth, in the County of Surrey,
MENTS IN FASTENINGS FOR DOORS
ول
"IMPROVE-
The principal object of my Invention is to enable the doors of theatres, and
other places of amusement or public resort to be immediately opened from the
inside, without having to unlock or in any way unfasten the same, when requisite
to provide a ready means of exit for the people assembled in such buildings, while
at the same time such doors will remain securely closed, and incapable of being
opened from the outside without the use of a key.
It consists in so arranging the door and its fastenings that when a sufficient
pressure is applied on the inside, the door will at once turn on its hinges and so
open outwards.
The door may be of any suitable construction and is fitted with any convenient
form of lock. It is hinged at one side to one door post in the ordinary manner,
while the other door post (against which the door closes) has a recess or box
formed at such a height from the ground, that when the door is closed the bolt of
the lock is opposite the same.
Within the box is mounted a lever or tumbler, pivotted preferably near the
middle of its length. A suitable spring is arranged so as to cause the outer end of
the lever, when in its normal position, to occupy such a position that the bolt of
the lock will be brought into contact with it when the door is closed.
In the case where the lock is fitted with a spring or latch bolt, the latter will be
forced inwards when brought into contact with the outer end of the lever or
tumbler, which is prevented from turning on its pivot or centre by its inner end
coming in contact with the outer wall of the recess or box. When the bolt has
passed the lever or tumbler it will spring out again, and the lever or tumbler will
then present an obstacle in the way of the bolt, against the door being opened.
On the requisite pressure being applied on the inside of the door, the force of the
spring tending to keep the lever or tumbler in its normal position will be overcome,
and the lever or tumbler caused to turn on its pivot until its outer end is clear of
the bolt of the lock, when the door will consequently be free to turn on its hinges.
Duien 31

page_text: It will thus be seen that in the case of panic or any sudden emergency the door
may be readily forced open by the simple pressure brought to bear on the inside,
without any preparation such as the unfastening of bolts or locks, while at the
same time, until required, the door remains closed.
The outside of the door has neither handle nor projection of any kind so that it
is impossible to pull the door outwards, and it can consequently only be opened
from this side by turning back the bolt of the lock by means of a key in the usual
way.
In the case where a lock with a shot bolt is employed (and which could
consequently not be forced inwards except by means of a key), either the lever or
tumbler will have to be arranged so as to allow it to turn inwards sufficiently to
permit the bolt (when in its shot position) to pass by it, on the door being closed,
and suitable means provided to cause it to assume its normal position again when
the bolt has passed it; or the door will always have to be closed first before
shooting the bolt by means of the key. In either case the arrangement in other
respects will be similar to that above described, so that the door will open as soon
as sufficient pressure is exerted on the inside.
In cases where it is not desired to open the door at all from the outside, the
lock might be abolished and a permanent projection be secured to the edge of the
door in place of the projecting bolt.
The arrangement of fastening described might also be applied to ordinary doors
in houses, suitable handles being provided, on one or both sides thereof, so that the
door would simply require to be pushed from the inside or pulled from the outside
to open the same, without having to turn the handle so as to release the bolt as in
the ordinary arrangement of fastening.
When applying the fastening to swing doors the lever or tumbler would naturally
have to be arranged so as to permit the door to open in either direction.