AN IMPROVED SAFETY LOCK to be as follows :-
Year: 1888

page_text: Dits of Application, 30th Apr., 1888
Complete Specification Left, 25th Jan., 1889
Complete Specification Accepted, 2nd Mar., 1889
I, CARL ARNHEIM, of 36 Rosenthalerstrasse, Berlin in the German Empire, Safe
Manufacturer, do hereby declare the nature of said invention for "AN IMPROVED
SAFETY LOCK to be as follows :-
"
This invention relates to a lock which can be operated from outside by a key only
when certain back slide rods can enter corresponding recesses. The object of the
invention is to provided mechanism by which these recesses are closed and opened.
The lock mechanism is contained in a frame in a recess of which a main locking
dise may be turned on a central hollow collar serving it as guide through a limit
of 180° from one position to another. On the end of the central hollow collar which
projects through the back plate of the lock is fixed a cap having two wings which by
striking against a stud fixed in the back plate limits the stroke of the main disc
to 180° On its front side the main locking disc has two parallel projections over
which a number, say eight, of round steel discs with corresponding recesses may be
slid. These discs are of different diameters and are each provided with a tongue by
which they engage between the two parallel projections on the front of the main
locking disc, a disc of uneven number engaging by its tongue from above and a disc
of even number from underneath, between the parallel projections. The position of
the eight discs is in a vertical sense governed partly by the two parallel projections on
the front of main locking disc and partly by eight tumblers oscillating on a pivot,
which act so as to press those of the eight discs 1 to 8 of uneven number upwards
and those of even number downwards. The whole arrangement of discs and tumblers
is secured from horizontal displacement by fixing the key hole plate to the parallel
projections on front of main locking disc and by the cover plate.
The main locking disc has a recess which in a certain position of the same forms a
channel for the entrance of a slide rod; in any other position the slide rod would not
come opposite the recess and consequently not enter it. The eight tumblers in two
sets, a top set and a bottom set are also recessed so that each set may receive a slide
rod in a similar way, and which can only enter when they are in a certain position,
and in order to bring about this position and therefore to open the lock the key is

page_text: inserted into the key hole, pressed against a piston held by a spring until it reaches
the proper position and then turned round 180°. Any kind of key having the form
of the keyhole may be inserted and the piston pressed back by it, there not being up
to this point any obstacles to overcome, but as soon as the key and with it the main
locking disc and also steel discs 1 to 8 are turned, these latter change their position
owing to their being mounted eccentrically to the key hole; their tongues enter the
wards of the key, and the tumblers 1 to 8 are brought one after another into the
position in which the slide rods may enter the aforesaid recesses, which is reached
when the key has been turned round 180°. To obtain this result the key is made of
a peculiar form, the bit having outside two plain smooth surfaces only and as well as
the shaft having several internal wards in which the several tongues of discs 1 to 8
may engage. With a key not made exactly to fit the lock, the main locking disc may
be brought into the correct position and the recess in same made free for the passage
of the corresponding slide rod, to prevent which the main locking disc has a notch
formed in its periphery and one of the tumblers next to the same a catch which may
be located in a recess in the frame. If now a key is used which does not exactly
coincide with the tumblers the catch will upon a certain position being reached
engage in the notch of main locking disc and prevent any further forward
movement.
As the tongues of discs 1 to 8 engage within the interior wards of the key, this
cannot be withdrawn until it is brought back to the commencing position, conse-
quently it is not practicable with any form of pick lock to bring one after another
the tumblers into such a position that the channels in tumblers and main locking disc
respectively are free, but rather after each vain effort to open the lock thoy pass back
into the commencing position before a second attempt can be made.
Dated this 30th day of April 1888.
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C.,
Agents for the Applicant.

page_text: 1, CARL ARNHEIM of 36 Rosenthalerstrasse, Berlin, in the German Empire, Safe
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 :-
This invention relates to a lock which can be operated from outside by a key, only
when certain back slide rods can enter corresponding recesses. The object of the
invention is to provide mechanism by which these recesses are closed and opened.
In the accompanying drawing the said lock mechanism is shewn in front view in
Fig. 1, the cover plate D (Figs. 2 and 4) being removed. Fig. 2 is a side view. Fig. 3
a vertical section through line A-B. Fig. 4 a horizontal section through line C-D,
and Fig. 6 a front view of the lock in the open position with both the cover plate D
and key hole disc S removed. (Figs. 1, 3, and 4).
The lock mechanism is contained in a frame R the form of which may be under-
stood from Figs. 1, 4 and 6. In a recess of this frame, the locking disc H (Figs. 1, 3
and 6) can be turned round 180° from the position shewn in Fig. 1 into the position
On the end of the
shewn in Fig. 6, its hollow boss Z carrying and guiding it.
central hollow boss Z which projects through the back plate of the lock is fixed in any
suitable way a cap N having two wing pieces f (Figs. 2 and 4) which by striking
against the stud t fixed in the back plate limits the stroke of the main disc H to 180°.
On its front side the main locking disc H has two parallel projections (Figs. 1
and 3 to 6) over which a number-say eight, as shown) of circular steel discs s¹ to s
(Figs. 1, 3, 4 and 6) may be slid. These discs are of different diameters and are each
provided with a tongue to by which they engage between the two parallel
projections, a disc of uneven number (Fig. 10) engaging by its tongue from above,
and a disc of even number (Fig. 11) from underneath between the projections l. The
position of the eight discs s to s is in a vertical direction governed partly by the
projections and partly by each one of eight tumblers P¹ to P³ (Figs. 1, 3, 5 and 6).
The discs of uneven number s¹, s³, etcetera, are pressed upwards by tumblers P1, P³,
etcetera; and those of even number 2, s, etcetera, by tumblers P², P, etcetera,
downwards. The uneven tumblers turn on pivot 2, the even on pivot (Figs. 1, 5
and 6), the former by the lower and the latter by the upper of the spiral springs a
to a fixed to ¹ or 2, being pressed against discs s² to 6 by the springs acting on
22

page_text: studs c¹ to c in tumblers P¹ to P8. The whole arrangement of discs and tumblers is
secured from horizontal displacement by the key hole disc S being fixed to the
projections, and by the cover plate D.
The main locking disc H has a recess A which in the position Fig. 6, forms the
channel K2 and allows the entrance therein of the slide rod II. In any other position
of the disc H (Figs. 1, 3, and 5) the slide rod II upon entering channel K²
would come butt against the solid metal of the said disc. The inuer end of
channels K' and K³ is formed by corresponding slots in tumblers P₁ to P³, through
which latter, channels K and K only go clear through when the tumblers are over
one another in the position shewn in Fig. 6. In any other position the slide rods I
and III come against all (Fig. 1) or some of the tumblers Pi to 18.
In order to bring about the position shewn in Fig. 6 and therewith to be able to
open the lock, the key is inserted in the key hole of disc S, brought into the right
position by pressing back the closing block d backed up by spiral spring r, and then
turned round 180°.
Any kind of koy corresponding to the form of the key hole may be inserted
therein and the closing block or piston d pressed back by it, there not being, as shewn
in Figs. 1, 3 and 4 up to this point and in this position any obstacles to overcome.
but as soon as the key and with it, the main locking disc H and also steel discs s' to s
are turned, these latter change their position relatively to the key hole because they
are mounted excentrically to the same; their tongues enter the wards of the key
(Fig. 8) and the tumblers P' to Ps are thereby enabled one after another to arrive in
the position shewn in Fig. 6, which they do when the key has been turned round 180°,
and at the same moment that the recess A of the locking disc H meets or comes flush
with the outer end of channel K2.
To obtain this result the key is of a construction, as shown in Figs. 7 to 9, and
quite different to any hitherto known form, the bit having outside two plain unbroken
surfaces, and internally it and also the shaft is so recessed out as to form several
internal wards in which the several tongues, may engage. As the wards lic
covered over, it is impracticable to make an exact fac simile of the same, or take a
copy thereof, and the slightest inexactness has at once for consequence that the one or
the other of the discs s and of their tumblers P does not work properly and thereLy
channel K or K³ blocked.
With a key not made to exactly fit the lock the main locking disc H would how-
ever be brought into the correct position and channel K² made free in its whole
length. To prevent this the main locking disc H is provided with a notch E,
(Figs. 1, 5 and 6) in its periphery and the lowest tumbler Ps of the upper series with
a projecting catch piece w, the latter generally having a place found for it in a recess
of the frame R.
If an attempt is now made to operate the lock with a key which does not exactly
coincide with the tumblers, the catch piece w will upon the position shewn in Fig. 5
being reached engage in notch E of locking disc H and prevent any further forward
movement.
As the tongues to engage in the internal wards of the key this cannot be
withdrawn until it is brought back to the commencing position (Fig. 1). It is there-
fore not practicable with any form of pick lock to bring one after another the tumblers
into such a position that the channels K' to K³ are made free, but rather after cach
unsuccessful effort to open the lock, the commencing position (Fig. 1) must be
returned to before a fresh attempt can be made.
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. A safety lock the key of which is formed with wards internally within the bit
and shaft, so that these have an outwardly smooth unbroken surface, at the sides, for
the purpose specified substantially as described and shewn.

page_text: 2. The combination of the locking disc H and a number of tongue discs s, with
tumblers P by which a precise adjustment of the slots formed in these latter, by
means of false keys, skeleton keys or pick locks is prevented substantially as described
and shown.
3. The combination of the notch E in locking disc H with catch pin w carried by
the lowermost tumbler Ps, of the upper series by which means the adjustment of the
recess A by false keys, skeleton keys or pick locks is prevented substantially as
described and shewn.