Improved Means of Locking and Unlocking Emergency Exit Doors.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improved Means of Locking and Unlocking Emergency Exit Doors.
I, THOMAS EVERITT HEWITT, of 115, Newington Causeway, London, S.E., Lamp
Manufacturer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improved means of securing and releasing the emer-
gency exit doors of public buildings and has for its object to enable the door
to be secured or bolted both at top and bottom and yet to be released from the
inside in case of emergency or panic, not only without the application of any
pressure against the door or its fastenings but even without the exercise of
volition on the part of the persons seeking to escape; and whilst ensuring the
secure fastening of the door against outside access by unauthorized persons, to
enable the door to be readily opened from the outside in case of need.
According to my invention the locking of the door or doors, in the case of a
pair, is effected by a bolt rising through the floor or sill and entering a socket
on the door the bolt, in so rising, raising another bolt contained in the said
socket and extending the whole height of the door, into engagement with a
socket or
staple in the lintel of the door frame. The release of the said bolts
is effected by the depression, under the weight of the person seeking exit, of a
hinged tread piece or floor flap situated at the inner threshold of the doorway
and for this purpose the first mentioned or floor bolt is suitably guided and
adapted to be raised by a counterweight and to be drawn down by the pressure
of the said flap upon a lever connected with the bolt, the other or top bolt
descending in its socket by its own weight.
In order to retain the floor bolt in the drawn down or retracted position when
the door is opened, a weight-actuated detent is adapted to engage with it and
in order to render the bolts self-locking by the mere act of closing the door, a
trigger is adapted to disengage the detent from the bolt, the trigger projecting
into position to be acted on by the heel of the door just before the door reaches
its closed position so as to permit the bolts to be shot up into their sockets when
the door is quite closed.
Although I prefer to employ weights for actuating the bolt and detent, springs
might be used instead of weights.
The flap would preferably be so placed within the embrasure of a porch, at
the end of a corridor, or in other situation where it is not liable to be accidentally
trodden on by persons walking about within the building, but in order to guard
against the door or doors swinging open if the flap be so accidentally depressed,
a spring-pressed hall latch or equivalent retaining device may be provided, to
keep the door closed unless actually pressed against from the inside and ensure
it-being automatically relocked after being accidentally unfastened.

page_text: To enable the door to be unbolted from the outside, the long bolt may be
provided with a handle extending through a slot in the door to the outside and
enclosed within by a locked cover.
Dated this 25th day of November 1898.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
COMPLETE SPECIFICATION.
Improved Means of Locking and Unlocking Emergency Exit Doors.
I, THOMAS EVERITT HEWITT, of 115, Newington Causeway, London, S.E., Lamp
Manufacturer, 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:-
My invention relates to means of securing and releasing the emergency exit
doors of public buildings and has for its object to enable the door to be bolted
both at top and bottom and yet to be instantly and automatically unfastened in
case of emergency or panic, not only without the application of pressure against
the door or its fastenings but even without the exercise of volition on the part
of the persons seeking to escape.
The invention also has for object to enable the door to be unlocked from the
outside in case of need.
Reference is to be had to the accompanying drawings forming part of this
specification wherein I have illustrated the invention as applied to a pair of doors
opening outwards, it being understood that the mechanism would be exactly
the same for a single door and that in the case of double swing doors each leaf
or door would be provided with a similar set of mechanism, the two mechanisms
working independently. Figure 1 is an inside face view of a pair of doors,
partly broken away and partly in section to shew the fastening and releasing
devices. Figure 2 is a vertical cross-section on line 1-1 Figure 1.
A A are the two leaves or doors hinged in the usual manner and rebated at
their meeting edges so that the door A being closed first it will be held closed
by the overlapping rebated edge of the door A to which alone, in the present
example, the fastener is applied. The said fastener comprises a bolt B fitted
to rise through the floor just inside of the sill of the doorway and adapted to enter
a socket C fixed to the door A the bolt in so rising, raising another bolt D
extending the whole height of the door and fitted to work preferably in a con-
tinuous tubular guide socket extending the whole height of the door the lower
end of said tube forming the socket in which the bolt B is received. This bolt D
when thus raised engages in a staple or socket E on the lintel of the door frame
so that the door is locked at bottom by the bolt B and at top by the bolt D.
The bolt B is fitted to work in a guide band is engaged by a lever F fulcrumed
at upon a fixed support mounted in the usual space H below the floor inside
the threshold of the door, the tail end of the lever having attached a counter-
weight G sufficient to overcome the gravity of the bolts Band 1) and of the flap
hereafter referred to, and to raise the bolts into engagement with the respective
sockets or staples C and E. The unfastening of the said bolts, in case of emer-
gency, is effected by the depression, under the tread of the person or persons

page_text: seeking exit, of a hinged flap I let into the floor and covering the space H in
which the mechanism is contained. This flap extends the full width of the
doorway and is of such breadth as to ensure it coming into action before the
person seeking exit can bring pressure to bear against the door. It is hinged
at and rests by its free edge upon a vertically sliding thrust rod F¹ suitably
guided and whose lower end rests upon the arm of the lever F, or instead of a
separate thrust rod the flap may rest directly (or through a friction.roller) upon
an upwardly projecting arm in one with the lever F. In either case the effective
radius at which the pressure upon the flap I is brought to bear upon the lever F
is such that the counterweight will be thereby immediately overcome and the
bolt B will be drawn down whilst the bolt D descends by its own weight, thus
permitting the door to fly open when pressed against from the inside. The bolt B
when thus drawn down is retained in the retracted position (so long as the door
remains open) by the engagement with the lower head 61 of the bolt B, of a
detent K which is pivoted at k and is pressed into engagement with the head b¹
by a weighted arm K¹ immediately the bolt B is lowered.
In order to permit the bolts B and D to be thrown into the locked position
by the act of closing the door, a trigger L is mounted on the end of a sliding
rod or link in position to project upwards through a slot in the door sill, or
just at the inner side thereof, so as to be acted on by an abutment near the
heel of the door A just before the door reaches its completely closed position;
this link is connected to the detent K so that when the trigger is acted on
the detent will be disengaged from the bolt B and the two bolts B and 1) will
then be shot by the action of the weighted lever Fimmediately the door is
quite closed. In order to render the bolts inoperative if desired, the abutment
by which the trigger L is so acted on may be a bolt M or other movable device
accessible to the door keeper and capable of being set for acting on the trigger
as described, or of being raised or moved out of operative position so as to permit
of the door being closed without the trigger being acted on. The trigger, instead
of being mounted so as to slide, may be a lever pivoted in position to project
up through the slot so as to be acted on in the way described in respect of the
sliding trigger L, the link being in that case connected to the detent K at
the opposite side of the pivotal centre of the latter so as to retract it by a thrust
instead of by a pull as described.
The flap I would normally be raised at its free edges above the floor level and
its depression would be limited by fixed stops I by which the flap would be
supported at about the floor level when depressed under the weight of persons
treading upon it. In order to prevent the flap being raised by unauthorized
persons, a stop is fixed to the door jamb as at N.
It is preferred that all the parts of the mechanism contained in the space H
should be mounted in a box-shaped casting so as to enable it to be readily placed
in operative position. The flap I would preferably be so placed within the
embrasure R of the doorway, at the end of a corridor, or in any other situation
where it is not liable to be accidentally trodden on by persons walking about
within the building, but in order to guard against the door or doors swinging
open if the flap be so accidentally depressed, a spring-pressed ball latch may
be provided so as to keep the door in the closed position unless actually pressed
against from the inside, the ball latch being capable of yielding under slight
pressure.
To enable the door to be unbolted from the outside the bolt D may be provided
with a handle P (shewn in Figure 2) which extends through a vertical slot 2
in the door A to the outside and is enclosed within a hinged cover Q secured
by a padlock or otherwise so that access can only be had to the handle P by
first unlocking the cover. The handle playing in the slot serves to limit the
range of motion of the bolt D and prevents it falling out of its guide socket when
the door is opened.

page_text: It is to be understood that although I have described, and prefer to employ,
weights for actuating the bolts and the detent, springs might be used in lieu
thereof.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed I declare that what
I claim is:-
:-
1. The combination with a door, of a bolt adapted to rise from below the floor
and to enter a staple or socket on the door, means tending to automatically raise
said bolt into engagement with the door, and of a hinged flap or platform adapted
to be depressed by the tread of a person upon it and to thereby disengage said
bolt from the door substantially as specified.
2. The combination of a bolt adapted when raised to enter a staple or socket
on a door, of a second bolt in alignment with, and adapted to be raised by, the
first mentioned bolt so as to enter a socket or staple above the door, and of
means tending to automatically raise both of said bolts into the locked positions
substantially as specified.
3. The combination with a door, of a bolt adapted to rise from below the floor
and to enter a staple or socket on the door, of a second bolt in alignment with,
and adapted to be raised by, the first mentioned bolt so as to enter a socket or
staple above the door, and of a counterweighted lever mounted in the space below
the floor and coupled with the said first mentioned bolt the action of the counter-
weight tending to raise both of said bolts into locked position substantially as
specified.
4. The combination with a door, of a bolt adapted to rise from below the floor
and to enter a staple or socket on the door, a second bolt adapted to be raised
by the first mentioned bolt so as to be thereby caused to engage in a staple or
socket above the door, a counterweighted lever coupled with the said first men-
tioned bolt so as to tend to raise both bolts, and of a hinged platform or flap
resting upon the counterweighted lever so as when depressed to cause the lever
arm coupled to the bolt to be depressed and the bolts to be retracted substantially
as specified.
5. The combination with a door, of a bolt adapted to rise from below the floor
and to enter a staple or socket on the door, a second bolt adapted to be raised by
the first mentioned bolt and to engage in a staple or socket above the door, a
counterweighted lever coupled with the said first mentioned bolt so as to tend
to raise the bolts, a platform resting on the said lever, and of a detent adapted
to retain the first mentioned bolt when the same is retracted by the depression
of the platform substantially as specified.
6. The combination with a door, of a bolt adapted to rise from below the floor
and to enter a staple or socket on the door, a second bolt adapted to be raised
by the first mentioned bolt and to engage in a staple or socket above the door,
a counterweighted lever coupled with the said first mentioned bolt so as to
tend to raise the same, a hinged platform or flap resting upon the counter-
weighted lever so as when depressed to cause the said bolt to be retracted, a
detent adapted to retain the said bolt in the retracted position, and of a trigger
coupled to the detent and projecting in position to be acted on by an abutment
on the door so as by the closing movement of the door to cause the detent to be
disengaged and permit the bolt to rise into engagement with the staple on the
door substantially as specified.
7. In the herein described door fastener the combination with the bolt fitted
to slide in a guide socket at the inner side of the door and adapted to engage
in a staple or socket above the door, and with a bolt adapted to be automatically
raised from below the floor and to thereby raise said bolt into locked position,
of a handle attached to said bolt and extending through a vertical slot in the
door to the outside thereof, and of a cover enclosing said handle on the outside,

page_text: and means of locking the same so as to prevent unauthorized access thereto
substantially as specified.
Dated this 10th day of M 1900
A. M. & WM CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.