Improvements in Devices for Undoing Latch and other Door Fastenings.
Year: 1896

page_text: Date of Application, 24th July, 1896-4ccepted, 29th Aug.. 1876
COMPLETE SPECIFICATION.
Improvements in Devices for Undoing Latch and other Door
Fastenings.
1. WILHELM MÜLLER of 1 Wilhelmstrasse, Holzminden on the Weser,
Brunswick, Germany, Official County Surveyor of Buildings, 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:-
The object of this invention is to effect the opening of doors, gates and the like
without the use of a key and if required from a distance by unfastening the catch
or catch plate. The invention is of special advantage in case of fire or other
accidents in closed spaces such for instance as churches, theatres, concert halls,
hospitals, barracks, factories and prisons.
Door locks and the like are generally used in connection with a catch or catch
plate for holding the latch or bolt and thereby also holding the lock and the door
fast against the door post. If the catch or catch plate be loosened from the
door post the door can be easily opened by a slight push against it without the
use of a key and without moving the latch or bolt. Such a detachable fastening
may according to my invention be produced by specially shaped bolts or hook bars
which engage with eyes provided on the catch or catch plate and can be drawn out
of the eyes by means of a lever or peg on the outside of the door post or by
electric devices from a distance. In the latter case the connection between the
catch or the catch plate with the door post is undone, and a slight pull or pressure
against the door suffices to draw the catch or catch plate with the eyes out of the
door post and to open the door, the construction of the lock having no influence.
Figs. 1 to 4 on Sheet 1 shew a catch with the mechanism for undoing it. The
latch handle on box a serves ordinarily for closing and opening of the door.
The latch engages with the catch g, and the catch e places itself behind the
closing nose. The catch g is riveted to a plate d provided with two eyes fffixed
to the back of it. The forkshaped bolt / enters these eyes for the purpose of
holding the catch g. The plate lies in a recess of another plate e which is fixed
to the door post. For undoing the plate d or the catch y the forkshaped bolt h
must be drawn back which is effected by a crank or tumbler & fixed on the rotatable
spindle and engaging with a recess in the bolt as shewn in Fig. 2. The handle i
on the door post serves to turn the spindle l. When the bolt h is drawn out of the
eyes ffa slight pressure on the door or handle suffices to pull the plate with the
catch g and eyes ff out of the door post and to open the door.
If the fastening is to be connected with an electric house or street circuit for
the purpose of announcing the opening of the door to a certain place such for
instance as that of a fire alarum, I provide two plates m and which terminate in
the conductor wires n and p and are brought in contact with the hook 7 on the
bolt h when the latter is pulled back.
In the same way connection may be made with an electric signal light
apparatus.
The bolt and the tumbler k, quite separated from the lock a, lie in an iron
box lateral to the catch g. The spindle / with handle i is also attached to this box.
The whole arrangement remains unaltered when the catch g is visible and not
covered by a box a.
The plate e is not absolutely necessary but is useful for conveniently securing
the plate d or catch g without their becoming displaced.
.

page_text: Fig. 5 Sheet 2 shews the application of a pinion & fixed on the spindle / and
engaging with teeth on the bolt h for actuating the latter.
Fig.
Sheet 2 shews another arrangement where the bolt h is connected to the
handle i by the link k. The dotted lines shew the position of the handle i and
link when the bolt is pulled out of the eyes f.
In Figs. 7 and 8 Sheet 3 is shewn how the handle i with spindle 2, the tumbler k
and the bolt h may be boxed in so as to be hid, the handle being turned by a
spiral spring r. As long as the catch g is not to be released, the pressure of the
spiral spring upon the handle i is neutralized by a pegs which is stuck through a
hole in the end of the handle. When this peg is pulled out by taking hold of a
handle on its outer end, then the spiral spring r presses on the handle i sufficiently
to turn it, to withdraw the bolt h and to free the catch g. These figures also shew
electric wire connections n. p.
Figs. 9 and 10 Sheet 3 shew the application of a helically coiled spring t,
whereby the handle i, tumbler k and spindle are quite omitted, the said spring
being applied to a central bar of the bolt or bolts h. The pressure of the spring
is neutralized by a removable pegs. If the latter is pulled out by the hand, or
as shall be presently described by an electromagnet, then the spring t expands and
brings the forkshaped bolt into the dotted position, drawing it out of the eyes f
of the catch g so that the latter can be drawn out and the door opened.
As it is a matter of minor importance I have not in Figs. 7 to 10 shewn the
means for again compressing the spring or t and bringing the bolt into the
eyes for again fixing the bolt therein. But it is very easily done by providing
the box with a small hinged lid for inserting the hand for pushing forward the
bolt and drawing back the spring or t. A special spindle with a small lever
to turn thereon from without may also be applied behind the neck of the bolt,
said lever swinging back when the stop peg's is withdrawn for closing the door;
by a small detachable outer handle the spindle can be turned for pushing the
bolt so far forward that the stop peg s can be inserted again.
Figs. 11 and 12 Sheet 3 shew an arrangement which is suitable in some cases,
and where the catch or catch plate is fixed by means of bolts. The curved
rotatable bolts are fixed on a spindle and engage with the eyes ff. The
spindle is between the plate e and the wall of the box or housing. It is turned
by means of the rods u u which are jointed to the bolts h and to a double armed
lever mounted on a spindle . The latter can be turned by hand by means
of a handle i or as shall presently be described through electric means by pulling
a stop peg or a stop lever a which serves to annul the pressure of a spiral
spring against a spindle in the box. By this turning action the bolts,
the rods and the lever arms & come into the dotted position whereby the
catch is unfastened.
This mode of bolt fastening is also applicable to the catch plates Sheets 2
and 4. And the mode of unfastening the bolts shewn in Figs. 19-23 Sheet 5 by
electrical means is also applicable to the arrangement shewn in Figs. 11
and 12.
In the case of doors that are entirely sunk into the recess and having a mortice
lock, or of doors having a lock with so called obtuse nose and lying in a recess in
the door frame, the latch, the bolt, and any subsidiary bolt engage with a catch
plate, which with folding doors is applied to the edge of one of the doors and with
single doors applied to the door post. Such doors may also be opened without the
use of a key by the means shewn in Figs. 13-16 Sheets 2 and 4. For this
purpose the specially shaped catch plate v is made detachable and provided with
one or more eyes on the back. The forkshaped bolts hhh take into the eyes f
and thus unite the catch plate with the door post. The teeth in the lower edge of
the body of the bolt / engage with the tooth sector k, on the spindle of which is
mounted a handle i; by turning the latter the bolts h are drawn out of the eyes f
and the catch plate v released from the door post so that the door can be opened
by a slight push or pull.

page_text: As shewn in Figs. 17 and 18 Sheet 4 the catch plate may be provided with a
vertical bolt arrangement instead of a horizontal one the eyes fare then arranged
horizontally, and the hook rod w takes the place of the bolts; this rod is formed
with a bar having teeth which engage with the tooth sector k. When the
handle i is turned the hooks of the rod w are drawn out of the eyes f, whereupon
the catch plate v can be detached and the door opened.
In order to prevent the unauthorized undoing of the catch g or catch plate v,
the handle i or the stop pegs is connected to the wall or door post by means of a
cord with lead seal which is torn by turning the handle i or by pulling out the
stop peg 3.
The catch or catch plate may also be released from a distance by electric
power.
In Figs. 19-22 Sheet 5 is shewn an arrangement for releasing the catch which
also, like in Figs. 7 and 8, depends upon the action of a spiral spring against the
handle i. The difference consists only in that the stop peg or stop lever al is
withdrawn or released by means of an electromagnet y. In Figs. 19 and 20 the
stop pegs is exposed to strong pressure between three rollers z, one of which is
mounted in the end of the lever i and the other two are arranged one on each
side of the pegs. The rollers are made of electrically insulating material such as
vulcanite, and for complete insulation a vulcanite disc is fixed on the upper end of
the peg s, whose other end terminates in a strong irou disc forming the keeper
to an electromagnet y. As soon as a suitably strong electric current passes
through this magnet, the keeper end of the pegs is attracted by it and the peg
slides off the end of the lever i; the pressure of the spring r then comes into action,
so that the lever i and tumbler k are turned back whereby the bolt is drawn out
and the catch g made releasable.
In Figs. 21 and 22 is shewn an arrangement wherein the lever i is not held by a
stop peg but by a stop lever a¹. The end of the latter where it touches the lever i
is provided with rollers of vulcanite or the like in order to facilitate the slipping
off. On the other end of the stop lever a' is fixed an iron weight for counteracting
the pressure of the spiral spring or the friction and forming the keeper to the
electromagnet y. When this magnet is energized the keeper is attracted, the stop
lever a' is released from the lever i, and the spiral spring presses the lever i and
the tumbler k so far back, that the bolt is pulled out of the eyes on the
catch g
In some cases for instance with large heavy doors where the pressure of the
spring against the lever i would be so great that an electromagnet would not
suffice for withdrawing the stop peg or stop lever u', the upper end of the lever i
may be made of an easily fusible alloy such as rose alloy (bismuth, lead and tin).
This part would then, as shewn in Fig. 23, lie against a fixed stop and would be
melted or burnt off by a suitably strong electric current, whereupon the lever i
would slide away from the fixed stop.
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
I claim is :-
1. The fixing of the catch or catch plate of a lock to the door post by means of
a bolt or rod in such manner that by the withdrawal of said bolt or rod by the hand
or by electricity the catch or catch plate is released from the door post so that the
door can be opened without the use of a key, while such opening may if desired be
indicated by an electric bell or signal light.
2. The constructions described with reference to Figs. 1 to 6 for carrying out
the invention as firstly claimed.
3. The construction described with reference to Fig. 7 and 8 for carrying out
the invention as firstly claimed.
4. The construction described with reference to Figs. 9 and 10 for carrying out
the invention as firstly claimed.

page_text: 5. The construction described with reference to Figs. 11 and 12 for carrying out
the invention as firstly claimed.
6. The construction described with reference to Figs. 13 and 14 for carrying out
the invention as firstly claimed.
7. The constructions described with reference to Figs. 15 to 18 for carrying out
the invention as firstly claimed.
8. The constructions described with reference to Figs. 19 to 23 for carrying out
the invention as firstly claimed.
Dated this 24th day of July 1896.
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.