An Improved Apparatus for Releasing the Fastenings of Doors and the like.
Year: 1895

page_text: Date of Application, 20th Feb., 1995-Accepted, 30th Mar., 1895
COMPLETE SPECIFICATION.
An Improved Apparatus for Releasing the Fastenings of Doors and
the like.
I, KARL GERSTMANN, of 16, Egonstrasse, Freiburg Br., in the Empire of
Germany, Master Locksmith, 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 an apparatus for opening doors and the like in which
the power requisite for opening the latch is obtained by the compression of a spring
on the complete opening of the door by any person passing through.
This controlling spring is capable of being disengaged from any desired point
by the operation of an electromagnet whereby the lock of the door is opened.
My improved apparatus is illustrated in the accompanying drawing, which shows
a view in elevation-partly in section.
The apparatus consists of a casing c adapted to rotate in bearings band having
an angular recess e¹ and an arm d, the free end of which carries a roller e adapted to
work in a guide provided on the door. A second casing f has a toothlike
projection g adapted to fit in the recess c¹ in the casing c and it is capable of sliding
in the direction of its axis in a slot . The two casings are connected together by
means of a rod i which is fixed to the casing fand is adapted to slide in a guide in
the closing screw plug of the casing c. This rod carries a disc against which a
spiral spring m contained in the case c bears. When the two casings are in
engagement with each other and the door is opened, the casing e is moved round
through the action of the arm and presses with the inclined face of its
recess against the inclined face of the tooth-like projection g, which causes
the casing to move downwards by which movement the free end of the lever n
becomes caught by the hook catch o, thereby preventing all upward movement
of the casing f which is now under the influence of the spring m.
On closing
the door, the casing remains in the position illustrated in the drawing.
Now if admittance is desired, the electromagnet is operated to effect the
disengagement of the hook catch o whereupon the spring draws the casing f
with its tooth-like projection into the recess e in the casing c, which
movement is transmitted by means of the bell-crank lever g and any suitable
connection to the latch of the door, so as to open the latter, whilst by the
further opening of the door the movement of the arm d serves to again reset
the apparatus.
I wish it to be particularly understood that I do not limit myself to the
precise details of construction herein before described and illustrated by the
accompanying drawing, but that I hold myself at liberty to make such changes
and alterations as fairly fall within the spirit and scope of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. An improved apparatus for opening doors and the like, substantially as
hereinbefore described and illustrated by the accompanying drawing.
2. An apparatus for opening doors or the like consisting essentially of two
casings c and f-engaging with one another by means of a tooth-which on being

page_text: twisted relatively to each other act to compress a spring m which remains
compressed when the door is closed and is released only by the operation of an
electromagnet p in such a manner that the action of the spring serves to open the
latch of the door, whilst the further opening of the door causes the spring m to be
again compressed by the person opening the door, as set forth.
Dated this 20th dox of Wah 1905
ROBERT E. PHILLIPS, M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent -