Improvements in Door-locks.
Year: 1893

page_text: Date of Application, 24th Mar., 1893-Accepted, 6th May, 1893
Improvements in Door-locks.
I, IVAN PAVLOVITCH, Chargé d'Affaires of the Servian Embassy, 71, Wilhelm
Strasse, Berlin, 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 liability of dwelling houses and other places to being entered by burglars,
has led to the adoption of the most varied protective measures, and the object
of the present invention is to prevent the possibility of a door being unlocked from
the outside when the householder is in his dwelling, and consequently has locked
the door from the inside. A lock which has this effect forms the subject of the
present invention.
Briefly indicated, the main feature of this invention consists in causing a steel
plate in locking the door from the inside-to pass in front of that key-hole
through which a key would have to be inserted from the outside in order to get
into the locked room. It therefore follows, and it is also apparent from a cursory
inspection of the drawing, that the outer key-hole and the inner key-hole must
not be and are not in a line with each other, so that, even when the outer hole is
barred, it is yet possible to insert the key on the inside.
The drawing hereto annexed represents two constructions of lock according to
my invention which vary from each other in certain details only, Figures 1, 2, 3, 4,
shewing one form of construction, and Figures 5 and 6 another form.
Figure 1 shews the internal arrangement of the lock, in the position which it
occupies when it has been opened either from the inside or the outside of the
door.
Figure 2 is the covering plate of the lock which has been removed from
Figure 1, shewing that the inner key-hole is in a different position from outer key-
hole.
Figure 3 shews the internal arrangement of the lock when locked from the
inside.
Figure 4 shews the internal arrangement of the lock when locked from the
outside.
It is clearly evident from the two latter figures, that the internal parts assume
different positions towards each other, according to whether the door has been
locked from the inside or from the outside, and it may here be mentioned that two
turns of the key are necessary to complete the locking or unlocking of the door.
In addition it should be stated that the position-which is not drawn-of the lock
upon the first turning of the key is the same whether the key has been inserted
from the inside or from the outside.
Figure 5 shews the internal arrangement of the alternative form of lock
according to this invention in the position which it occupies when it has been
opened either from the inside or the outside of the door.
Figure 6 shews the same as locked from the outside.
It may here be stated that the mode of operation, as shall be explained later
on, of the lock shewn in Figures 5 and 6 admits of only one turn for locking from
the outside, and of two turns when from the inside. Both modes of operation
have, however, one common feature, namely the automatic barring of one of the
two key-holes-that is, the outside one-which takes place when the door is
locked from the inside, but that both key-holes remain open when the door is
locked from the outside.
Entering more closely into detail, it will be seen that the lock shewn in
Figures 1, 2, 3, and 4 consists of a number of well known parts, of which it is

page_text: only necessary to note the bolt a and the tumblers 6 (the number of which is
optional), arranged in such a manner that the tumblers can be raised-and the
bolt shot only by means of the key-bit e.
is
The shutter c is preferably made of hardened steel and is intended to be pushed
before the outside key-hole f, and to bar it periodically. The shutter c
actuated by the bolt a in the following manner. Proceeding from the left the bolt-
head a pushes it towards the right, and on its right side pressure is exerted by
the spring, which is fastened to the tail of the bolt a so that, as a general thing,
the shutter c must follow the movements of the bolt a, if means are not employed
which may stop its passage from the right to the left.
One of the tumblers is provided with a tail i, the object of which is to keep
the shutter c locked in certain positions by means of the projection k formed upon
it. The shutter c is guided on the underside by the pins and m, Figure 1,
which are riveted to the lock-plate, and on the upper side by the lower edge of
the bolt a.
In order now to explain the mode of working the lock, it should be borne in mind
that the side seen by the person looking at the drawing is the inner side and that
it is necessary to imagine one's self placed behind the sheet of drawings in order to
have the outer side of the door before one.
1st method of operation. The door is locked from the inside.
The key is inserted into the key-hole g, and turned to the left, and thus by means
of the notch 1 the bolt is shot to the left by one turn, and the shutter follows,
under the influence of the spring h. This position as already mentioned has not
been drawn, as it offers nothing for observation. The key is now turned round a
second time and the key-bit engages with the notch 2 and shoots the bolt further
to the left, the shutter again following the movement of the bolt, but under the
following different circumstances. It will have been noted that at the end of the
first turn of the key, the projection assumed the dotted position of Figure 1,
and had laid itself with its left-hand edge against the tail of the tumbler, which
fact, however, is of no consequence inasmuch that the forward course of the shutter
had already been stopped by its forward end having laid itself against the rear side
of the bolt-head (see a c Figure 1). At the next moment, however, the position k¹
is of importance to the extent that, at the second turning of the key, the path of
the pin k must be cleared, if the shutter c is to continue its course. This is done by
the bit of the key lifting the tumbler b, so that the tail i goes upward and-on the
bolt a passing on-t
-the projection k slides along underneath the tail i. During this
movement the key-hole is covered, and any attempt to draw back the shutter with
criminal intent say by attempting to displace it from the outside by means of a
pointed instrument, is thoroughly prevented by the tail of the tumbler laying
itself behind the right-hand side of the projection k, see Figure 3. It is thus that
the outer key-hole is barred when the door is locked from the inside.
2nd method of operation. The door is locked from the outside.
The operations are essentially the same as in the first case, only it must be noted
that whilst before the key was inserted from the inside into the key-hole g, now it
is inserted from the outside into the key-hole f, and that whilst before the notches 1
and 2 were acting, now the notches 2 and 3 are used. If the key is turned round
once in the key-hole f, it engages with the notch 2 and shoots the bolt to the left;
the shutter c follows this movement unimpeded and the pin k again goes into the
position, Figure 1. At the second turn of the key, however, the movement of
the shutter in its relation to the tumbler and to the bolt differs materially from the
movement described in the first case. The position of the shutter as drawn in
Figure 4 has in fact already been taken up at the moment when the first turn of
the key was completed. It is plain from this figure, that the edge n of the shutter c
is already in the closest proximity to the key-hole f. If therefore the bit of the
key is turned further round, in the direction of the arrow o, the shutter is first of
all pushed further to the right, the spring h giving way. The shutter gets into its
position furthest to the right when the bit is in the position f¹. Now if the bit

page_text: passes from the dotted position f¹ into the dotted position f, the shutter c can not
recede any further than into the position drawn in Figure 4, because its edge n lays
itself against the pipe of the key. If the bit of the key turns further into the
position, the tumbler b falls into its lower position, and the tail i of the tumbler
gets to the left side of the pin k. If now the key is withdrawn from the key-hole f,
the hole will nevertheless remain open. This explains how the key-hole f is not
barred as in the first case, but remains open, when the door is locked from the
outside.
Upon reference to Figures 5 and 6 it will be seen that the shutter c here forms
one piece with the bolt a so that there is-in the broad tail of the bolt-only an
oblong opening p, q, r, s, at the upper edge of which there are two notches 1 and 2.
Further, the spring of Figures 1 to 4 is absent, and the tumbler b is of a more
simple form, as the tail i is also absent, there being therefore no pin k. Although
by this simplification of parts the motion of the plate which bars the outer key-hole
is a positive one, and therefore no longer dependent on a spring, only one turn of
the key can be made (Figure 6 therefore illustrates the position of the lock in its
locked state) when locking from the outside, whilst from the inside two turns can
be made, as the key is here inserted into the key-hole g.
1st method of operation. The door is locked from the inside.
no novel
The key is inserted into hole g and turned twice. There are
features in this case, as only during the second turn does the edge n' of the opening
in the bolt (p, q, r, s,) pass over the key-hole f and cover it.
2nd method of operation. The door is locked from the outside.
Here also there is nothing which has not been above described, except that―as
is clear from the drawing without any explanation-the bit of the key is prevented
by the edge n' from turning any further after the bolt has been shot by the first
turn of the key.
According to Figures 5 and 6 therefore, the bolt can be shot from the inside by
two turns of the key and from the outside by one only.
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 :-
C
1. A door lock comprising a bolt, a sliding shutter c actuated by a spring hand
provided with a projection k, and a tumbler 6 provided with a finger i adapted to
engage with the projection k, operating in such a manner that the keyhole f is
covered by the shutter c when the bolt is shot by two turns of the key in the key-
hole g but which will remain uncovered when the locking has been done through
the keyhole, the positions of the two keyholes being out of alignment with each
other; substantially as described.
2. In a lock of the type herein described, the formation of the bolt and the
sliding key-hole shutter in one piece, whereby the bit of the key is prevented from
making two turns when inserted from the exterior side of the door but is capable of
performing such two turns when inserted from the interior side of the door; sub-
stantially as described.
00.1 31
1 1000
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicant's Patent Agents.