New AND HOERUL IMPROVEMENTS IN LOCKS FOR DOORS
Year: 1855

page_text: LETTERS PATENT to Charles Gustav Mueller, of the State, of South
Carolina and United States of America, for the Invention of "CERTAIN
New AND HOERUL IMPROVEMENTS IN LOCKS FOR DOORS"
Sealed the 26th November 1855, and dated the 4th September 1855.
PROVISIONAL SPECIFICATION left by the said Charles Gustav Mueller
at the Office of the Commissioners of Patents, with his Petition, on the
4th September 1855.
I, CHARLES GUSTAV MUELLER, of the State of South Carolina, of the
United States of America, do hereby declare the nature of the Invention for
CERTAIN NEW AND USEFUL IMPROVEMENTS IN LOCKS FOR DOORS" to be as
follows:-
Fig. 1 represents a front view of the lock; Fig. 2 is a vertical side view of
one of the compartments of the lock; Fig. 3, a rear view of one of the chambers
of the lock; Fig. 4, a side view of the same chamber; Fig. 5, the back view
of the lock, its plate being removed, and the bolt thrown out and secured;
Fig. 6, a similar view, with the bolt thrown back into the lock, and the positions
of its connected parts; Figs. 7, 8, and 9 are transverse sectional views, taken
across the lock at various points; Fig. 10 is a perspective view of the knobs,
and the several pieces more immediately connected with them; Figs. 11, 12
and 18 represent three different views of the key. Similar letters in the several
Figures denote like parts.

page_text: To enable others skilled in the art to make and use my Invention, I will
proceed to describe the same with reference to the Drawings; first premising
that the shape and size of the lock may depend upon the special use to which
it is to be applied, and it may be a right or left hand lock, and with slight
modifications be placed on the inside or outside of a vault door, or be embraced
within the inner and outer plates of the door, without any change in its prin-
ciple of construction; my object being to construct a cheap yet strong and
effective lock, that shall be powder and burglar proof, and applicable to all
the purposes for which such locks are used.
H represents the handle which is used for throwing out and in the bolt Z,
and for operating other mechanism in the lock, as will be described. In the
knob His placed another smaller knob B, which may be either flush with
or made to project a little beyond the knob H, and applied so as to be capable
of being depressed towards the lock about one-fourth of an inch, and without
which depression the knob I cannot be turned or the bolt thrown. The
knob B, after it has been depressed and released, flies back into its regular
position again by the action of a spring 9, Figs. 2, 5, 10, within the lock.
A is the front plate of the lock, and is solid, except where the axis of the
knob H passes through it, and the narrow vertical openings through which
the pins or projections n, n, n, on the steel bars i, i, i, protrude. These vertical
apertures in the front plate are regulated in size according to the size and
inner mechanism of the lock. The pins n, n, n, can be moved up and down
in these apertures, and the bars i, i, i, of which they are part, constantly keep
the apertures closed up, so that neither powder, instruments, or anything else
can be introduced through them into the interior of the lock, which is thus
made powder and pick proof. There are springs s, s, s, Fig. 5, above the
plates or bars i, i, i, which operate indirectly on said bars, for forcing them,
and the pins n attached to said bars, back to their places after the power
by which they were previously moved up has been withdrawn. It will be
obvious, that instead of the projecting pins i, i, i, for operating the slides,
there may be depressions or holes in the bars, into which the key or other
instrument may be introduced for moving said bars, or said bars M may be
elevated by inclined planes or wedges, operated by the key, and by pressure
of its bolts against them. This would leave the front of the lock smooth,
and prevent the damaging of it, which may be done by breaking off the
pins when they are used, and if found essential these slides or bars may be
further protected by placing them farther in the lock, and reaching them
through small tubes or holes with a key properly prepared for such an
arrangement.

page_text: The lock is divided into two compartments by a plate I, which extends from
its front to its back, as seen in Figs 5, 6, a vertical side view of one of the
compartments being shown in Fig. 2. The bars i, i, i, move between the front
plate A, and a second plate D, behind it, a side view of one of them with its
projecting pin n being seen in its position between the plates A, D, in Fig. 2.
Behind the plate D is a series of other bars. M, each of which is about two-
thirds of the height of the lock in length, and its movement is the same as
that of each of the bars or plates i. The plate D has at its base an opening
or openings, of the same length as those in the plate. A, but the highest points
of the openings in D are below the lowest points of the openings in A, so as
not to come opposite each other. Through the opening in D protrudes a
piu m, Fig. 2, which is a part of or is connected to the bar M, and fits into
a suitable hole in the bar i, the bars M. and i being so connected by means of
said pin m they shall have corresponding movements. When the pin n is
lifted it carries the bar i, and by means of the connecting pin m it also
carries the bar M with it. The bars M slide between the plates D and L, L,
and are separated fron. each other by thin plates of metal (as seen, Fig. 5),
which serve as ways or guides for the movement of said bars M, of which
three are shown. On top of each bar M is a spiral spring s, which presses it
down when no power is applied to keep it up. The lower parts of the bars M
have rack teeth (Figs. 2, 10,) cut in them, which in length should be a little
more than that of either of the openings through which n and m are pro-
truded. r, r, r, Fig. 2, represent round holes, drilled into the bars M
respectively, and large enough to receive and contain the horizontal slides
fff, which will be hereafter described more particularly. The bars M,
beyond what has been mentioned, are solid. In Fig. 10 is represented, in per-
spective, the knob H and its several devices in place for operating the bars M.
C is the axis or shaft of the knob H, and passes through plates A and D.
Through this axis, which is tubular, is fitted a rod p, which connects the inside
or small knob B with the interior mechanism of the lock. A pin m", passing
through the rod.p, serves to keep the knob B from moving out beyond a
certain distance, or about flush with the knob H. z is a pivot on the rod p,
by which a thin short piece of metal h is attached to it, and which rests loosely
in an opening in the lever l, attached to a rod t, which extends from one side
of the lock to the other, and is supported in the plates Q and G (Fig. 5), passing
through an opening in the plate I. Opposite to the collective center of the
bars M, on the rod or shaft t, there is placed another lever d, which extends
downward, and rests on or against a steel plate r, which is moveable in
grooves cut in the plates I, G, (Figs. 2, 5.) This plate r is connected at its

page_text: center with a spring 9, which is permanently attached to the bottom of the
block by a screw ". The spring works loosely in an opening in plate r,
through which it extends, and it presses the plater towards or against the
lever d. When unrestrained by any external pressure, the spring g keeps the
plater (which has its edge next the bars M wedge-shaped) about one-fourth
of an inch distant from the bars M opposite the upper of the rack teeth, as
seen in Fig. 2. When in this position, as the plater presses against the lever
or arm d, so will the lever or arm 7 press against the rod p, and when the
knob B is forced out by p to its greatest extent it will be flush with the knob
H. From this arrangement of parts, it is obvious that if the knob B is pressed
in, the rod p will press against the arm or lever l, which, partially turning the
shaft t, will cause the lever to press the plater down into the rack teeth
in M, it making no difference into what position the bars M may have been
lifted. When this has been done (and it must be done before the knob H can
be turned in order to throw back the bolt) every one of the bars M, and the
bars i, i, i, with which they are connected, are rendered entirely immoveable,
and cannot therefore be made to produce any friction on the inner side of the
lock as long as they are thus held by the plate r; and as the horizontal slides
fff, (Fig. 2,) which have to be forced into the holes in the bars M, are
a short distance from the surface of the bars M before the knob H is turned,
it follows that these slides f' cannot be pushed or pressed against the bars M
before they have been fastened by the plate r, thus making any friction between
the bars M. and slides f impossible, and consequently making the picking of
the lock just as impossible, for locks can only be picked by producing friction
between the parts, and ascertaining how the various parts fit each other, and
at what points or elevations. An expert lock-picker first ascertains with his
implements the avenues to the bolt, by raising and lowering or by pressing
against the parts to feel which yield and which are rigid, and at what
particular positions they are thus yielding or rigid, and so he discovers his
way to the bolt. Now, by fastening rigidly the bars M in my lock, I
remove any and every possibility of arriving at the particular part that holds
them from moving, as nothing will move those parts but the key that placed
them there.
The axis C of the knob H is square beyond plate D (Fig. 7), and on its
square part has a circular plate W, which of course moves with the knob.
On the rod p behind the plate W is attached a steel arm T, by means of a collar
R around the rod, and which can be turned round on the rod p, whilst it is
prevented from sliding either way horizontally on the rod by the flanges 2, 2.
The plate W has a hole VI in it, as seen in Fig. 6, into which the arm T fits,

page_text: and at the two extreme points to which the hole VI can be brought by the
turning of the plate W there are holes about one-fourth of an inch deep in
the first plate D of the lock, of the same diameter as the hole in the plate W.
The arm T is of such a length as to be able to rest with its point in
either hole of the plate D when the hole VI has been brought opposite to
either, and when the rod p with its knob B is flush with the knob H, as seen
in Fig. 10. When the arm T rests in either of these holes in plate D
the plate W of course is immoveable, and this position exists at the two
extreme points L" and K", Fig. 6, or in other words, when the lock is in its
entirely locked or entirely unlocked state. During the intervening movement,
and in order to make the knob H moveable, the knob B is pressed upon,
and this will lift the arm T out of the hole in plate D of the lock, but it
will remain in the hole VI, and thus be carried around until it comes to
the second hole, into which it will drop if the pressure on the knob B is
removed by the action of the spring g, before described. This contrivance
completes the fastening of the bars M by plates r partially before and during
the turning of the knob H.
The plate W is not entirely circular, that part of it between the dotted radial
lines (Fig. 6) being of smaller diameter than the remaining portion. This
leaves the point m² farther from the center than n¹, say, about one-fourth of
an inch, for a purpose to be described. Figs. 5 & 6 show the bolt Z from
the back; y is a projecting point on it, upon which the circular plate W, by
means of its two points n¹ and m¹, acts to move the bolt out of the lock or
into it. On turning the knob H, and by it the plate W, in the direction of
the arrow, Fig. 6, the point n¹ will be brought to act on the pin or point y, and
will thus move the bolt out of the lock. When the bolt is out to its fullest
extent the point n¹ will clear itself of the projection y and will pass it. Fig. 5
shows the position of plate W, and of the bolt Z after the latter has been
moved forward, and after n¹ has passed the projection y. By reversing the
motion of the knob, the point m¹ being longer or projecting from the center
of motion farther, will throw back the bolt, into its original position. The
plate W (Fig. 5) after throwing out the bolt, can be moved, say, one-eighth of
a circle more, when it is stopped by a screw in the front plate of the lock,
which prevents it from turning farther. This one-eighth circular movement is
intended to operate other mechanism in the lock, and, as above said, is applied
while the bolt is out and at rest, the special purpose of which will be hereafter
explained.
The plate W (Figs. 3, 4, 5, & 6,) has a projection on its surface,
which works the forked lever U. The projection k is so arranged that it will

page_text: not come up to and touch the fork a before the point n' has cleared itself of
point y after throwing out the bolt Z; but when this does take place, then the
projection will move up the fork x. Now, by reversing the motion of the
plate W. (by turning the knob H), the projection k will first press down fork w
of the lever U, and on continuing the motion, the bolt Z will again be thrown
into or inside of the block. It will be perceived, in Figs. 2, 4, 5, that the
lever is secured to the axis v, the ends of which rest in plates I and G.
Inside of these plates and close to each are attached segment wheels P (Fig. 2).
on the aforesaid shaft v, which catch into and work forward and backward the
rack N, which is the lower part of the plate, marked S, N, y, (Figs. 5 and 4.)
The upper and lower part of said plate (marked N and y) are shaped as
plates; and the part S is a square piece of metal, which connects N and y,
that part S being only about half the width of those N and
tion is on the side of the plate I, which has an opening cut into it sufficiently.
large to allow of the moving of N, S, y, forward & back, for, say, one half
an inch. The part S projects into a compartment as far as the extent of the
movement of the bolt will admit, while N, S, y, slides in the square openings
in plate I. N & y have grooves in the plate G (Figs. 5, 6,) which corre-
spond in depth to the opening in plate I.
Y.
This connec-
115
In Figs. 4 and 5 is shown a plate marked II, with holes drilled through it
with great care as to symmetry, which serve for a purpose to be described..
The plate II is attached permanently to plate G (Fig. 5), and extends across
to the plate I.. It is about half an inch thick, more or less, and its height is
such that it just fits between N and y (Figs. 3, 4, 5), and consequently N and y
can be moved over the plate II. When the projection k moves up the lever U
this result will be produced, viz., the moving of N, y, over II; and when the
projection depresses the lever U, the plates N and y will be withdrawn from
plate II.
Figure 9 represents the bolt Z from below, in the same position as it is
shown from behind in Fig. 6. In the same Fig. 9. N, S, y, is also shown from
below, as it is shown sidewise in Fig. 4. The bolt Z has a square opening at
its back part, which slides over and fits exactly into plate S. The first inove-
ment of the knob I throws out this bolt Z without affecting the part N, S, y;
but after the bolt is out, then the part N, S, y, is thrown into the position
shown in Fig. 3; then the piece S is thrown behind the extreme back of the
bolt Z, as seen from below in Fig. 8, and from behind in Fig. 5.
Fig. 6 represents the bolt Z and piece S (the latter in dotted lines) in the
same positions as Fig. 9 represents it from below, and it will be seen that it is
jmpossible to slide back the bolt unless the piece S has first been removed

page_text: from behind it, which can only be done after the proper key has been applied
to open the lock. To N and y are attached in a line with S, though not quite
so wide as S, and at equal distances, three steel rods, e¹, Fig. 6, (though they
may be more or less in number than three,) the length and breadth of which
are shown in dotted lines in Fig. 2; their thickness is seen in Fig. 6. To
these rods e¹, e¹, e¹, are attached horizontal sliding pins f¹, I, g', (Fig. 9,) the
ends fand g of which are round, and the center part I square; in their
centers they have an oblong opening, by means of which they are snugly
hung on the rods e', and they can be moved up and down on the rods.
The holes in plate II, Fig. 5, aredrilled in a line opposite to each of the
ends g', g, g', of these horizontal sliding pins, and the holes in the bars
M, M, M, are opposite to the ends f, f, f, of the horizontal sliding pins.
When the plate N, S, y, is moved to the back of the lock, as shown in Fig. 3,
it will carry with it the horizontal sliding pins just spoken of, and.these pins
will then be pushed into and rest in the holes of the plate II (Fig. 2.) When
in this position their ends f', f', f, are then, say, one sixteenth of an inch
distant from the vertical bars M, M, M, and the holes ¹ in said bars M being
opposite to f(when said bars are at their lowest position, and when the hori-
zontal sliding pins rest in the lower holes of plate II, into which they will
be pushed, unless lifted by exterior force), the ends f¹ will, on moving the plate
N, S, y, forward (as in Fig. 4), be pushed (after having passed over the dis-
tance intervening between them and the bars of an inch as above stated)
into the holes of bars M (see Fig. 2). While the ends f¹ rest in the bars
M, the moving upwards of the latter will also give a corresponding motion to
the horizontal slides, of which f¹ are the ends. The bars M are lifted by the
lifting pins n, and it is the key which effects this. The key has a bit for each
pin n, and said bits are capable of being extended to such lengths as will
correspond with each hole in plate II; or, in other words, the distance ver-
tically of said holes being marked on each bit of the key, and each bit being
adjustable to either of these distances, the key is therefore capable of lifting
(by being applied to the pins n) the horizontal slides f¹, I, g', from the positions
they occupy into other positions. Assuming that by means of a key, such as
described, the horizontal pins have been lifted to either of its positions, the
ends will, by moving the plate N, S, y, to the back of the lock (as in
Figs. 2, 3), be pushed into such holes of plate II, to which they may have
been brought opposite to or in line with. If; then, the key is withdrawn from
the pins n, m, n, the pressure of the springs s (Figs. 2, 5,) will bring the bars
M into their original position, as shown, from the rear in Fig. 5.
ends
As the
of the horizontal pins f, I, g', cannot be pushed through the solid

page_text: portion of the bars M, it follows that these bars have to be lifted to exactly
the same height again to which they were lifted first by the key, in order to
bring the hole in each bar again directly opposite to each end of the horizontal
pins f, to admit of moving the plate N, S, y, back again, and of course
forcing into the holes of the bars. The key can then be withdrawn, and
as the springs s can act again, they will of course press down the bars M,
which will carry down with them the horizontal pins, and bring these again
into the same original position shown in Fig. 6.
After this the key may be
altered to suit the operator or user, that is, the length of one or more bits may
be altered, which of course will effect a different location of the horizontal pins
in plate II, and thus almost any number of changes may be made in the lock.
Having locked the lock with a certain combination of bits, the slightest varia-
tion from that combination will make the opening or unlocking with the key
impossible.
Figures 11, 12, & 13 represent different views of the key. F' is a plate,
which contains grooves, in which fit, so as to be movable at pleasure, the bits
p, p, p. These bits have small rills cut into them at equal distances, and
which are regulated according to the plate II in the block. H' is a plate,
which is secured to the plate F¹ by two screws 1, ; and thus the bits p¹ are
contained between the two plates Hand F. The openings in plate F¹,
through which the screws 7, 1, extend, are, say, one-eighth of an inch long,
so that plate F can be moved to and fro. On the inner side of the plate
F¹ there are small projections, which, when the cuts in the bits p' are brought
in a line with them, can be pushed into said cuts, and thus fasten the bits.
By moving the plate F in one direction its projections will be withdrawn from
the incisions of the bits p', and they then can be drawn out to vary their
length or change their combination, and the bits may be marked with letters,
figures, or lines, so that the combination may be recorded, and when this
has been done, they can again be fastened by returning the plate F to its
first position. M' is a small knob on plate F, which facilitates the handling
of the latter, the key in its entirety being very small indeed for even a very
large lock.
The manner of locking the lock is as follows:-After the key has been
given a shape to suit its user, it is applied below the pins n, n, n, and it is then
moved upwards, which cause the bits to slide up the pins the distance for
which they were set. When the points e, f, of the key have reached the top
of the projection N₁ (Figs. 1, 2), the key is pressed at its foot close to the front
plate A of the lock, and rests on the projection N¹, where it will remain of itself
without holding it with the hand. The knob B is then pressed down with the

page_text: thumb, and by means of the fingers of the same hand the knob H is turned
around until the bolt is thrown out; the thumb is removed from B, and it
returns to its former position. The key is then removed, and the locking is
completed. To unlock again, the key is introduced as before, the thumb
applied to B, and the motion of the knob H reversed.
If the person in charge of the key wishes to change its combination after
he has locked the lock with it, to make it almost an impossibility for any other
person into whose hands the key might fall to open the lock with it, he should
note carefully the shape which he gave to it at the operation of locking, as
otherwise he would have as little probability of unlocking the lock as any
other person not having the right shape of the key would have. The key
may be so made as to require weeks before the whole combinations could be
gone through with.
Having thus fully described the nature of my Invention, what I claim
therein as new, and desire to secure by Letters Patent is, first, a key provided
with extension bits, the individual length of each of which can be altered at
pleasure, and still be applicable to the lock, as described.
I claim, in combination with the knob and the series of bars or tumblers M,
a device or mechanism, which when put in movement to unlock the bolt shall
lock the said tumblers, or when its movements are reversed shall unlock the
tumblers and lock the bolt.
And, in combination with the main bolt Z, I claim the secondary bolt or
part S, operated substantially as described.
I also claim the movable carriage or part N, S, y, and its series of sliding
pins in combination with the series of tumblers M, and stationary perforated
plate II (or its equivalent).
I also claim the arrangement of the plates M, and slides f¹, for preventing
any friction, and so as to prevent the possibility of feeling how the plates or
slides are connected, as set forth.
I also claim the bars M having saw-toothed racks, as arranged with the
sliding bars i, and the projecting pins m for operating them from the outside
of the lock, as described.
I also claim the arrangement of the horizontal changeable sliding pins,
which are moved by the bars M, the rack toothed wheels or segments, and
forked lever U, which is moved by the projection on the circular plate W, as
set forth.
I also claim as arranged the bars M, and the stationary plate II for holding
the pins when they are withdrawn from said bars, as described.
I also claim the arrangement of the knob, the collar R with its bent arm

page_text: T, and the circular plate W for turning and holding said plate, substantially as
described.
I also claim as arranged the rod p of the inner knob, the lever l, shaft t,
lever d, plate r, and its spring g, for connecting said knob with the bars M,
and operating them, as set forth.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Gustav Mueller in the Great Seal Patent Office
on the 3rd March 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
GUSTAV MUELLER, of the State of South Carolina and United States of
America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of September, A.D. 1855, in the nine-
teenth year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Charles Gustav Mueller, Her special license that
I, the said Charles Gustav Mueller, my executors, administrators, and assigns,
or such others as I, the said Charles Gustav Mueller, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an In-
vention of "CERTAIN NEW AND USEFUL IMPROVEMENTS IN LOCKS FOR DOORS," upon
the condition (amongst others) that I, the said Charles Gustav Mueller, by an
instrument in writing under my hand seal, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six cale::dar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Charles Gustav Mueller, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement (that is to say) :-
Figure 1 represents a front view of the lock; Figure 2, a vertical side view
of one of the compartments of the lock; Figure 3 represents a rear view of
one of the chambers of the lock; Figure 4 is a side view of the same

page_text: chamber; Figure 5 is the back of the lock, its plate being removed, and
the bolt thrown out and secured; Figure 6 is a similar view, with the bolt
thrown back into the lock, and the position of its connected parts; Figures
7, 8, and 9 are transverse sectional views, taken across the lock at various
points; Figure 10 is a perspective view of the knobs, and the several pieces
more immediately connected with them; Figures 11, 12, and 13 represent
three different views of the key. Similar letters in the several Figures denote
like parts.
To enable others skilled in the art to make and use my Invention, I will
proceed to describe the same with reference to the Drawings, first premising
that the shape and size of the lock may depend on the special use to which
it is to be applied; and it may be a right or left hand lock, and with slight
modifications be placed on the inside or outside of a vault door, or be embraced
within the inner and outer plates of the door, without any change in its
principle of construction; my object being to construct a cheap yet strong
and effective lock that shall be powder and burglar proof, and applicable to all
the purposes for which such locks are used.
:
'H represents the handle which is used for throwing out and in the bolt Z,
and for operating other mechanism in the lock, as will be described. In the
knob H is placed another smaller knob B, which may be either flush with or
made to project a little beyond the knob H, and so applied as to be capable of
being depressed towards the lock about one-fourth of an inch, and without "
which depression the knob H cannot be turned or the bolt thrown. The
knob B, after it has been depressed and released, flies back into its regular
position again by the action of a spring g, Figures 2, 5, 10, within the lock.
A is the front plate of the lock, and is solid, except where the axis of the
knob H passes through it, and the narrow vertical openings through which
the pins or projections n, n, n, on the steel bars i, i, i, protrude. These
vertical apertures in the front plate are regulated in size according to the size
and inner mechanism of the lock. The pins n, n, n, can be moved up and
down in these apertures, and the bars i, i, i, of which they are part, constantly
keep the apertures closed up, so that neither powder, instruments, or anything
else can be introduced through them into the interior of the lock, which is
thus made powder and pick proof. There are springs s, 8, s, Figure 5, above the
plates or bars i, i, i, which operate indirectly on said bars, for forcing them,
and the pins n attached to said bars, back to their places after the power by
which they were previously moved up has been withdrawn. It will be
obvious, that instead of the projecting pins i, i, i, for operating the slides, there
may be depressions or holes in the bars, into which the key or other instrument

page_text: may be introduced for moving said bars; or said bars M may be elevated by
inclined planes or wedges, operated by the key and by pressure of its bolts
against them. This would leave the front of the lock smooth and prevent
the damaging of it, which might be done by breaking off the pins when they
are used, and if found essential these slides or bars may be further protected
by placing them farther in the lock, and reaching them through small tubes
or holes with a key properly prepared for such an arrangement.
The lock is divided into two compartments by a plate I, which extends from
its front to its back, as seen in Figures 5 and 6, a vertical side view of one of
the compartments being shown in Figure 2. The bars i, i, i, move between
the front plate A, and a second plate D, behind it, a side view of one of them
with its projecting pin n being seen in its position between the plates A, D, in
Figure 2. Behind the plate D is a series of other bars M, each of which
is about two-thirds of the height of the lock in length, and its movement is
the same as that of each of the bars or plates i. The plate D has at its
base an opening or openings, of the same length as those in the plate A,
but the highest point of the openings in D are below the lowest points
of the openings in A, so as not to come opposite each other. Through
the openings in D protrudes a pin m, Figure 2, which is a part of or is con-
nected to the bar M, and fits into a suitable hole in the bar i, the bars M and
i being so connected by means of said pin m that they shall have correspond-
ing movements. When the pin n is lifted it carries the bar i, and by means
of the connecting pin m it also carries the bars M with it. The bars M
slide between the plates D, and L, L', and are separated from each other by
thin plates of metal (as seen in Figure 5), which serve as ways or guides for
the movement of said bars M, of which three are shown. On top of each
bar M is a spiral spring s, which presses it down when no power is applied to
keep it up.
The lower parts of the bars M have rack teeth (Figures 2
and 10) cut in them, which in length should be a little more than that of
either of the openings through which m and n are protruded. 1, 1, 1,
Figure 2, represent round holes drilled into the bars M respectively, and large
enough to receive and contain the horizontal slides f¹, f, f, which will be
herein-after described more particularly. The bars M, beyond what has been
mentioned, are solid. In Figure 10 is represented, in perspective, the knob H
and its several devices in place for operating the bars M. C is the axis of the
knob H, and passes through plates A and D; through the axis, which is
tubular, is fitted a rod p, which connects the inside or small knob B with the
interior mechanism of the lock. A pin m", passing through the rod p, serves
to keep the knob B from moving out beyond a certain distance, or about flush

page_text: with the knob H. z is a pivot on the rod p, by which a thin short piece of
metal is attached to it, & which rests loosely in an open in the lever l,
attached to a rod t, which extends from one side of the lock to the other, and
is supported in the plates Q and G (Figure 5), passing through an opening
in the plate I. Opposite to the collective center of the bars M on the rod or
shaft t there is placed another lever d, which extends downward, and rests
on or against a steel plate r, which is moveable in grooves cut in the plates
I, G, (Figures 2 and 5.) This plate r is connected at its center with a spring 9,
which is permanently attached to the bottom of the lock by a screw h". The
spring works loosely in an opening in plate r, through which it extends, and
it presses the plater towards or against the lever d. When unrestrained by
any external pressure, the spring g keeps the plate r (which has its edge next
to the bars M wedge-shaped) about one-fourth of an inch distant from the
bars M opposite the upper of the rack teeth, as seen in Figure 2. When in
this position, as the plater presses against the lever or arm d, so will the
lever or arm press against the rod p, and when the knob B is forced out
by p to its greatest extent it will be flush with the knob H. From the
arrangement of parts it is obvious, that if the knob B is pressed in, the rod p
will press against the arm or lever 1, which, partially turning the shaft t, will
cause the lever d to press the plate down into the rack teeth in M, it
making no difference in what position the bars M may have been lifted.
When this has been done (and it must be done before the knob H can be
turned, in order to throw back the bolt), every one of the bars M, and the
bars i, i, i, with which they are connected, are rendered entirely immoveable,
and cannot therefore be made to produce any friction on the inside of the
lock as long as they are thus held by the plate r; and as the horizontal slides
fff, (Figure 2,) which have to be forced into the holes in the bars M
are a short distance from the surface of the bars M before the knob His
turned, it follows that these slides cannot be pushed or pressed against
the bars M before they have fastened by the plate 1, thus making any friction
between the bars M and slides f¹ impossible, and consequently making the
picking of the lock just as impossible; for locks can only be picked by producing
friction between the parts, and ascertaining how the various parts fit each
other, and at what points or elevations. An expert lock-picker first ascertains
with his instruments the avenues to the bolt, by raising and lowering, or
by pressing against the parts to feel which yield and which are rigid, and at
what particular positions they are thus yielding or rigid, and so discovers
his way to the bolt. Now, by fastening rigidly the bars M in my lock, I
remove every possibility of arriving at the particular part that holds them

page_text: from moving, as nothing will move these parts but the key that placed them
there.
The axis C of the knob H is square beyond plate D, Figure 7, and on its
square part has a circular plate W which of course moves with the knob. On
the rod p behind the plate W is attached a steel arm T, by means of a collar R
around the rod, and which can be turned around on the rod p, while it is pre-
vented from sliding either way horizontally on the rod by the flanges ¹, . The
plate W has a hole VI in it, as seen in Figure 6, into which the arm T fits;
and at the two extreme points to which the hole VI can be brought by the
turning of the plate W, there are holes about one-fourth of an inch deep in
the first plate D of the lock, of the same diameter as the hole in the plate W.
The arm T is of such a length as to be able to rest with its point in either hole
of plate D, when the hole VI has been brought opposite to either, and when
the rod p with its knob B is flush with the knob H, as seen in Figure 10.
When the arm T rests in either of these holes in plate D, the plate W of
course is immoveable, and this position exists at the two extreme points Lu
and R, Figure 6; or, in other words, when the lock is in its entirely locked or
entirely unlocked state. During the intervening movement, and in order to
make the knob H moveable, the knob B is pressed upon, and this will lift the
arm T out of the hole in plate D of the lock, but it will remain in the hole VI,
and thus be carried around until it comes to the second hole, into which it will
drop if the pressure on the knob B is removed by the action of the spring g,
before described. This contrivance completes the fastening of the bars M by
plater, partially before and during the turning of the knob H.
The plate W is not entirely circular, that part of it between the dotted
radial lines (Figure 6) being of smaller diameter than the remaining portion.
This leaves the point m' farther from the center than n', say, about one-fourth
of an inch, for a purpose to be described. Figures 5 and 6 show the bolt Z
from the back. y is a projecting point on it, upon which the circular plate W,
by means of its two points n¹ and m¹, acts to move the bolt out of the lock or
into it. On turning the knob H, and by it the plate W, in the direction of the
arrow, Figure 6, the point n¹ will be brought to act on the pin or point y, and
will thus move the bolt out of the lock. When the bolt is out to its fullest
extent the point n¹ will clear itself of the projection y, and will pass it. Figure 5
shows the position of the plate W, and of the bolt Z after the latter has been
moved forward, and after n' has passed the projection y. By reversing the
motion of the knob, the point m' being longer, or projecting from the center of
motion farther, will throw back the bolt into its original position. The plate W,
Figure 5, after throwing out the bolt can be moved, say, one-eighth of a

page_text: circle more, when it is stopped by a screw in the front plate of the lock, which
prevents it from turning further. This one-eighth circular movement is intended
to operate other mechanism in the lock, and, as above said, is applied while the
bolt is out and at rest; the special purpose of which will be herein-after
explained.
The plate W (Figures 3, 4, 5, and 6,) has a projection k on its surface,
which works the forked lever U. The projection k is so arranged that it will
not come up to and touch the fork x before the point n' has cleared itself of
point y after throwing out the bolt Z; but when this does take place, then the
projection will move up the fork a. Now, by reversing the motion of the
plate W (by turning the knob H) the projection k will first press down fork w
of the lever U, and on continuing the motion the bolt Z will again be thrown
into or inside of the lock. It will be perceived, in Figures 2, 4, and 5, that
the lever U is secured to the axis v, the ends of which rest in plates I and G.
Inside of these plates, and close to each, are attached segment wheels P
(Figure 2) on the aforesaid shaft v, which catch into and work forward and
backward the rack N, which is the lower part of the plate, marked S, N, y,
(Figures 5 and 4). The upper and lower part of said plate (marked N and y)
are shaped as plates, and the part S is a square piece of metal which connects
N and y, that part S being only about one half the width of those N & y. This
connection is on the side of the plate I, which has an opening cut into it suffi-
ciently large to allow the moving of N, S, y, forward and back, say, one half inch.
The part S projects into a compartment as far as the extent of the movement
of the bolt will admit, while N, S, y, slide in the square openings in plate I.
N and y have grooves in the plate G (Figures 5 and 6), which correspond in
depth to the opening in plate I.
In Figures 4 and 5 is shown a plate, marked II, with holes drilled through
it with great care as to symmetry, which serve for a purpose to be described.
The plate II is attached permanently to plate G (Figure 5), and extends
across to plate I; it is about half an inch thick, more or less, and its height is
such that it just fits between N and y (Figures 3, 4, and 5), and consequently N
and y can be moved over the plate II. When the projection moves up
the lever U, this result will be produced, viz., the moving of N, y, over II;
and when the projection k depresses the lever U, the plates N and y will be
withdrawn from plate II.
Figure 9 represents the bolt Z from below, in the same position as it is shown
from behind in Figure 6. In this same Figure 9, N, S, y, is also shown from
below, as it is shown sidewise in Figure 4. The bolt Z has a square opening
at its back part, which slides over and fits exactly into plates S. The first

page_text: movement of the knob H throws out the bolt Z without effecting the part
N, S, y; but after the bolt is out, then the part N, S, y, is thrown into the
position shown in Figure 3, then the piece S is thrown behind the extreme
back of the bolt Z, as seen from below in Figure 8, and from behind in
Figure 5.
Figure 6 represents the bolt Z and piece S (the latter in dotted lines), in the
same positions as Figure 9 represents it from below; and it will be seen that
it is impossible to slide back the bolt unless the piece S has first been removed
from behind it, which can only be done after the proper key has been applied to
open the lock. To N and y are attached in a line with S, though not quite so
wide as S, and at equal distances, three steel rods e', Figure 6, (though they
may be more or less in number than three,) the length and breadth of which
are shown in dotted lines in Figure 2; their thickness is seen in Figure 6. To
these rods e¹, e', e¹, are attached horizontal sliding pins f¹, I, g', (Figure 9,) the
ends f¹ and g¹ of which are round, and the center part I square; in their
centers they have an oblong opening, by means of which they are snugly hung
on the rods e¹, and they can be moved up and down on the rods. The holes in
plate II, Figure 5, are drilled in a line opposite to each of the ends g', g¹, g³,
of these horizontal sliding pins, and the holes in the bars M, M, M, are oppo-
site to ends f,f,f', of the horizontal sliding pins. When the plate N, S, y,
is moved to the back of the lock, as shown in Figure 3, it will carry with it
the horizontal sliding pins just spoken of, and these pins will then be pushed
into and rest in the holes of the plate II, (Figure 2). When in this position,
their end f, f, f¹, are then, say, one-sixteenth of an inch distant from the
vertical bars M, M, M, and the holes r¹ in said bars M being opposite to f¹,
(when said bars are at their lowest position, and when the horizontal sliding
pins rest in the lower holes of plate II, into which they will be pushed unless
lifted by exterior force,) the ends f¹ will, on moving the plate N, S, y,
(as in Figure 4), be pushed (after having passed over the distance intervening
between them and the bars one-sixteenth of an inch, as above stated,) into the
holes of the bars M (see Figure 2). While the ends f¹ rest in the bars M,
the moving upwards of the latter will also give a corresponding motion to the
horizontal slides, of which f' are the ends. The bars M are lifted by the lifting
pins n, and it is the key which effects this. The key has a bit for each pin n,
and said pins are capable of being extended to such lengths as will correspond
with each hole in plate II, or, in other words, the distance vertically of said
holes being marked on each bit of the key, and each bit being adjustable to
either of these distances, the key is therefore capable of lifting (by being
applied to the pins n) the horizontal slides f¹, I, g', from the positions they
forward

page_text: occupy into other positions.
Assuming that by means of a key, such as
described, the horizontal pins have been lifted to either of its positions, the
ends g will, by moving the plate N, S, y, to the back of the lock, (as in
Figures 2 and 3,) be pushed into such holes of plate II to which they may
have been brought opposite to or in line with. If, then, the key is withdrawn
from the pins n, n, n, the pressure of the springs 8 (see Figures 2 and 5) will
bring the bars M into their original position, as shown, from the rear in
Figure 5. As the ends f¹ of the horizontal pins f¹, I, gl, cannot be pushed
through the solid portion of the bars M, it follows that these bars have to be
lifted to exactly the same height to which they were lifted first by the key, in
order to bring the hole in each bar again directly opposite to each end of the
horizontal pins f¹, to admit of the moving the plate N, S, y, back again, and of
course forcing f¹ into the holes of the bars. The key can then be withdrawn,
and as the springs can act again, they will of course press down the bars M,
which will carry down with them the horizontal pins, and bring these again
into the same original position, shown in Figure 6. After this the key may be
altered to suit the operator or user, that is, the length of one or more bits
may be altered, which of course will effect a different location of the hori-
zontal pins in plate II, and thus almost any number of changes may be made
in the lock. Having locked the lock with a certain combination of bits, the
slightest variation from that combination will make the opening or unlocking
with the key impossible.
Figures 11, 12, and 13 represent different views of the key. F' is a plate
which contains grooves, in which fit so as to be moveable at pleasure the bits
p',pp. These bits have small rills cut into them at equal distances, and
which are regulated according to the plate II in the lock. H' is a plate
which is secured to plate F¹ by two screws 1, 1, and thus the bits p¹are con-
tained between the two plates H' and F¹. The openings in plate F', through
which the screws 1, 1, extend, are, say, one-eighth of an inch long, so that
plate F¹ can be moved to and fro. On the inner side of plate F¹ there are
small projections, which when the cuts in the bits p¹ are brought in a line with
them, can be pushed into said cuts, and thus fasten the bits. By moving
plate F¹ in one direction, its projections will be drawn from the incisions of
the bits p', and they then can be brought out to vary their length or change
their combination, and the bits may be marked with letters, figures, or lines, so
that the combination may be recorded; and when this has been done, they can
again be fastened by returning the plate F¹ to its first position. M¹ is a
small knob on plate F, which facilitates the handling of the latter, the key in
its entirety being very small indeed for even a very large lock.

page_text: The manner of locking the lock is as follows:-After the key has been given
.a shape to suit its user, it is applied below the pins n, n, n, and it is then moved
upwards, which causes the bits to slide up the pins the distance for which they
were set. When the points e, f, of the key have reached the top of the projec-
tion N', Figures 1 and 2, the key is pressed at its foot close to the front
plate A of the lock, and rests on the projection N¹, where it of itself will remain
without holding it with the hand. The knob B is then pressed down with the
thumb, and by means of the fingers of the same hand the knob His turned
around until the bolt is thrown out, the thumb is removed from B, and it
returns to its former position; the key is then removed and the locking is com-
pleted. To unlock again, the key is introduced as before, the thumb applied
to B, and the motion of the knob reversed.
If the person in charge of the key wishes to change its combination after he
has locked the lock with it, to make it almost an impossibility for any other
person in whose. hands the key might fall to open the lock with it, he should
note carefully the shape which he gave to it at the operation of locking, as
otherwise he would have as little probability of unlocking the lock as any
other person not having the right shape of the key would have. The key
may be so made as to require weeks before the whole combination could be
gone through with.
Having thus fully described the nature of my Invention, what I claim
therein as new, and desire to secure by Letters Patent, is, first, a key provided
with extension bits, the individual length of each of which can be altered at
pleasure and still be applicable to the lock, as described.
I claim, in combination with the knob and the series of bars or tumblers M,
a device or mechanism, which, when put in movement to unlock the bolt, shall
lock the tumblers, or when its movements are reversed shall unlock the tum-
blers and lock the bolt; and, in combination with the main bolt Z, I claim the
secondary bolt or part s, operated substantially as described.
1 also claim the moveable carriage or part N, S, y, and the series of its
sliding pins, in combination with the series of tumblers M and stationary per-
forated plate II (or its equivalent).
I also claim the arrangement of the plates M, and slides f¹, for preventing
any friction, and so as to prevent the possibility of feeling how the plates or
slides are connected, as set forth.
I also claim the bars M having saw-toothed racks as arranged, with the
sliding bars i and the projecting pins m for operating them from the outside of
the lock, as described.
I also claim the arrangement of the horizontal changeable sliding pins

page_text: which are moved by the bars M, the rack-toothed wheels or segments, and
forked lever U, which is moved by the projection on the circular plate W,
as set forth.
I also claim as arranged the bars M, and the stationary plate II for holding
the pins when they are withdrawn from said bars, as described.
I also claim the arrangement of the knob, the collar R, with its bent arm
T, and the circular plate W, for turning and hold said plate, substantially as
described.
I also claim as arranged the rod p of the inner knob, the lever l, shaft t,
lever d, plate r, and its spring g, for connecting said knob with the bars M,
and operating them as set forth.
In testimony whereof, I have hereunto set my signature and seal, this
Eleventh day of January, One thousand eight hundred and fifty-six.
CHARLES GUSTAV MUELLER. (L.S.)