Improvements in Safety Locks and Latches.
Year: 1898

page_text: Improvements in Safety Locks and Latches.
We, THEODORE BRAND, of 322, Prospect Avenue, Brooklyn, Watch Maker,
and MAX FEHRMANN, of 660, Carrol Street, Brooklyn, Musical Director, both in
the State of New York, United States of America, do hereby declare the nature
of this invention to be as follows:-
This invention relates to locks and latches and consists of a safety device having
the purpose of preventing the picking of the lock by means of a skeleton key.
The locking device may be of any known kind, either with a shooting bolt
or with a latch bolt, and either operated entirely by the turning of the key or
only opened by the key and closing by spring action.
The mechanism which forms the subject of the present invention relates only
to the operating devices which actuate the lever that works the locking bolt,
and which are as follows. The said operating lever is formed on a cylindrical boss
that can turn in a recess formed in the back plate of the lock and in a corre-
sponding circular hole in a plate covering the same, and the boss has a screw-
threaded hole which faces a hole formed in a second plate above the first one
and also a corresponding hole in the front plate of the lock. In the narrow
space between the front plate and the second inner plate is a slide which accord-
ing to one arrangement is held by a spring in a position in which it covers the
hole in the second plate so that the key cannot be passed through. The end
of the slide opposite the spring is connected by a flexible band to a fixed point
on the second plate, which has a slot behind the flexible band so that if a finger
to be presently described is pushed against the flexible band at that point it forces
the band in a loop through the slot and thereby causes the band to withdraw
the slide from the hole so as to allow the key to be passed through.
On the outer plate is fixed a tubular projection, the upper end of which is
closed by a fixed plug having a central screw-threaded hole which is in line
with the beforementioned holes in the lock plates and the screw-threaded hole
of the beforementioned boss of the actuating lever.
Within the tubular projection is a sliding plug, to which are attached cranked
bars that project through lateral slots in the tubular projection and carry at
their outer end the beforementioned finger that acts upon the flexible band of
the keyhole slide. This plug also has a screw-threaded hole in line with the
other holes, and it is ordinarily kept up against the fixed plug by means of a
spring, which may be arranged either outside or inside the tubular projection,.
in which position the finger is withdrawn from the flexible band and the slide
is consequently held over the key hole by its spring.

page_text: The holes of the fixed and sliding plugs have the same screw threads, but the
thread of the hole in the boss of the lever is either of a different pitch or of the
contrary direction, or it may be both. The key consists of a stem having at its
end a screw thread, corresponding to that of the hole of the lever boss, and at
an intermediate part of its length it has a screw thread corresponding to that of
the fixed and sliding plugs.
For opening the lock, the key is first screwed through the hole of the fixed
plug, it is then pushed forward so as to force the sliding plug down the tubular
extension, whereby the slide is withdrawn from the hole of the front lock plate
as described so that the threaded end of the key can pass through. The key
is then screwed through the sliding plug so that it can then be pushed forward
to the boss of the actuating lever, into which it is then screwed home, after
which the boss and lever can be turned so as to draw back or raise the lock
bolt or latch of the further rotation of the key.
The outer end of the latter may either be formed with a loop like that of an
ordinary key, or it may be formed as a crank handle for facility of rotation.
Instead of actuating the key hole slide by means of a finger and flexible band
as described, the slide may be connected to the one arm of an elbow lever, the other
arm of which is connected to the sliding plug by a rod, so that on pushing down
the sliding plug it actuates the elbow lever so as to withdraw the slide.
If still greater security be desired, there may be provided more than one
sliding plug, each one having a hole with a thread of a different pitch, or of a
different direction, the key being formed with a corresponding succession of
different screw threads.
Dated this 4th day of January 1898.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Safety Locks and Latches.
We, THEODORE BRAND, of 322, Prospect Avenue, Brooklyn, Watch Maker,
and MAX FEHRMANN, of 660, Carrol Street, Brooklyn, Musical Director, both in
the State of New York, United States of America, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:
This invention relates to locks and latches and consists of a safety device having
the purpose of preventing the picking of the lock by means of a skeleton key.
The locking device may be of any known kind, either with a shooting bolt
or with a latch bolt and either operated entirely by the turning of the key or
only opened by the key and closing by spring action.
The mechanism which forms the subject of the present invention relates only
to the operating devices which actuate the lever that works the locking bolt,
and which are as we will describe with reference to the acompanying drawings
in which:-
Figure 1 is a top view of our improved lock; Figure 2 is a plan of the lock;
Figure 3 is a side elevation, partly a section thereof; Figure 4, a transverse
section on line 4-4, indicated in Figure 3.

page_text: Figure 5 is a similar view shewing the position of the parts of the lock after
the key has passed through the first stage.
Figure 6 is a similar view shewing the position of the several parts of the
lock with the key inserted in the lock.
Figure 7 is a sectional view, similar to that in Figure 4 shewing modified
arrangement of the parts in the key-way;
Figure 8 is an elevation of the key, made in the shape of a crank.
In the accompanying drawing we have shewn our invention adapted to a
spring lock such as is generally used on doors. The mechanism of the lock
proper consists of the bolt a, springs s and s¹, catcher c and case b. These parts
are those of the ordinary pattern and construction, and are not claimed as parts
of our invention.
The safety attachment claimed as our invention consists of the following:
Opposite key-holes (f' and h¹) we provide a circular flange 61 in the case of the
lock and a circular hole in corresponding position in the plate d covering the
inner plate of the case 6 of the lock.
In this circular flange b' is set a plug e having its upper end recessed and
snugly fitted into the hole d¹ of the plate d. To this plug e is secured (or
produced in one piece therewith) the arm e¹ which is shaped according to the
construction of the lock and serves the same purpose as the ward of a key. It
may be made in the shape as shewn in Figure 2 of the drawing, and adapted
to engage the upward bent end a¹ of the bolt a, or it may be provided with clefts
or grooves as the construction of the lock may require.
....
Above 'the plate d, covering the mechanism of the lock, is arranged a second
plate which is provided with a circular key hole f¹ in concentrical position
with the hole d'. This hole f¹ is normally covered by the sliding plate g held
in its position above the hole f1 by springs gl and by a flexible wire fabric g
secured to the plate f by pin g³ Plate f, and also plate h surmounting it, are
each provided with a slot i as shewn in Figure 1.
Upon the plate h which is also provided with a circular hole h¹ in corresponding
position above the holes f¹ and d', in plates f and d respectively, is set the tubular
key-way j concentrically with the hole h¹, and in it are provided the two blocks k
and k¹. Block is stationary, preferably soldered in the mouth of the key:
way, whereas block k¹ slides therein.
The ends of a looped wire frame 7 pass through the slots m provided on both
sides of the tubular key-way j and are secured to the sliding block k¹. A spiral
spring n wound around the key-way, or set inside thereof as shewn in Figure 7,
supports the sliding block k¹ and also the frame in their normal position.
Blocks and and also plug e are provided with screw-threads, preferably of
different pitch and grade and arranged changing from right hand to left or vice
versa.
These screw-threads in the blocks k and k' and plug e may be varied
almost indefinitely, also additional sliding blocks such as k¹ may be set in the
key-way or between the plates d and f as may be required for greater complica-
tion of the combined safe guard.
The key to be used for the operation of this lock consists of a slender
stem o provided with screw-threads q and q' (and with as many more as may be
necessary for the purpose of a different combination) arranged in corresponding
order with the blocks k and A, the screw-threads g on the end of the stem of
the key being made to correspond with that of the plug e. The key may be in
the shape of an ordinary key as shewn in Figures 5 and 6 or it may be in the
shape of a crank as shewn in Figure 8.
In the construction shewn in the drawings the screw-thread in the blocks k
and runs from left to right and the screw-thread in the plug e from right to
left. This is the simplest arrangement of a combination.
To insert the key in the lock protected by this combination it is necessary
first to screw the thread g first through the stationary block k (q' being of suffi-
ciently smaller diameter to pass freely through) then on pushing the key as far

page_text: as it will go, the block k¹ is pressed downward by the thread 9 as shewn in
Figure 5 and while held so in the depressed position, the key is screwed through
this block.
With the sliding block k¹, the frame 7 is moved downward, and in acting on the
flexible band g² it draws the plate g from its normal position, thereby freeing
hole for the key to slide into it, when screwed through the block A. Screw-
thread on the end of the stem of the key is then screwed into the plug e and
when their connection is sufficiently rigid, the key will turn the plug and move
the arm e as may be required to operate the lock.
The access to the outer key hole may be covered by a guard plate of any
known construction or by a screw block. The number of the blocks in the key-
way and the arrangement of the different screw-threads may be varied as already
explained above. The combination described there and shewn in the drawings
is only one example of the application of the principle of our invention.
The construction shewn in Figure 7 is modified inasmuch as the spring n is
set inside of the key-way directly underneath the block and between it and
the flange j, and in substitution for the flexible band g² a bell crank t is pivoted
to the key-way. One arm of this bell crank is connected by rod to block k
and the other to an eye attached to plate g. This arm passes through slot h²
provided in plate h and transmits to the plate g, the motion of the block k¹
connected to its other arm.
In this construction springs g¹ are omitted. Springs n might also be dispensed
with if the springs g₁ are used and are made sufficiently strong to return block /
to its normal position..
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
--
1. In a lock or latch, the combination with a locking bolt and its actuating
lever or equivalent device of safety appliances so constructed and arranged that
for effecting the unlocking a key consisting of a stem having two or more
different screw-threads formed thereon, requires first to be screwed through a
threaded hole in a guard plate or tube, then effects the depressing of a moveable
plug whereby a slide is withdrawn from an opening giving access to the unlock-
ing lever, the key being then screwed through the said plug and into a threaded
hole of the unlocking lever, whereupon the latter is actuated by turning the
key, substantially as described.
a
.
2. In a lock or latch, the combination with a locking bolt of a lover or
equivalent device for operating the same, rotatably mounted in the casing
and having a screw-threaded hole, a cover plate above such device having
an opening in line with such threaded hole, a sliding plate normally
covering
such opening,
second
such sliding
cover plate covering
plate and having an opening also in line with such threaded hole, a tubular
key-way fixed on the second plate, closed by a fixed plug and containing one or
more loose sliding plugs, such fixed plug and sliding plug or plugs having screw
threaded holes that are also in line with the said threaded hole, a spring holding
the sliding plug in an outward position against the fixed plug, and a device
connected to the sliding plug whereby on being moved inwards it moves the
sliding plate away from the hole which it covers, the said parts being combined
and adapted to be operated by a key consisting of a stem having two or more
different screw-threads thereon substantially as herein described with reference
to the drawing.
3. In a lock or latch such as is referred to in the first and second claims,
connecting the sliding plate to a flexible band, which is deflected for the with-
drawal of the sliding plate, by means of a frame connected to the sliding plug,
substantially as described with reference to Figures 1 to 6 of the drawings.
4. In a lock or latch such as is referred to in the first and second claims, con-
necting the sliding plate to the sliding plug by an elbow lever and rol so that

page_text: on the depressing of the plug the lever is made to withdraw the sliding plate
from the opening, substantially as described with reference to Figure 7 of the
drawing.
5. A key for a lock or latch such as is referred to in the preceding claims,
consisting of a stem o¹ having, two or more different screw-threads gq formed
thereon, substantially as described with reference to Figures 5, 6 and 8 of the
drawings.
6. A safety lock or latch constructed and operating as herein described with
reference to the drawings.
Dated this 2nd day of November 1898
ABEL & IMRAY,
Agents for the Applicant.