IMPROVEMENTS IN LOCKS
Year: 1877

page_text: LETTERS PATENT to John Charles Chubb and George Hayter Chubb, both of
No. 128, Queen Victoria Street, St. Paul's, in the City of London, for the
Invention of "IMPROVEMENTS IN LOCKS." A communication from abroad by
Theodor Kromer, of Freiburg, Baden, Germany.
Sealed the 6th October 1877, and dated the 14th July 1877.
PROVISIONAL SPECIFICATION left by the said John Charles Chubb and
George Hayter Chubb at the Office of the Commissioners of Patents on the
14th July 1877.
JOHN CHARLES CHUBB and GEORGE HAYTER CHUBB, both of No. 128, Queen
Victoria Street, St. Paul's, in the City of London. "IMPROVEMENTS IN LOCKS."
[A communication from abroad by Theodor Kromer, of Freiburg, Baen,
Germany.]
This Invention has for its object improvements in locks. For this purpose a
lock is formed of two cylinders, one, the outer one, fixed and forming part of the
lock case, the other capable of revolving within it, and carrying in its interior a
number of slides which lie across it one above the other, and project alternately
through slits formed in its two opposite sides, and enter corresponding slits formed
in the opposite sides of the interior of the outer fixed cylinder, thereby locking
together both cylinders, by, as it were, a series of cross bars which offer great
resistance to the lock being opened by force.
1444
The slides are of the same length as the diameter of the inner cylinder, and are
acted upon by springs in such manner as to press the alternate slides in opposite
directions, and cause their ends to project from opposite sides of the cylinder.
The pin, which serves as an axis for the key, stands up from the centre of the
inner cylinder, and the key is formed with steps or projections on two opposite
sides of its stem.
In the central part of each slide is a slot, against the sides of which the key acts.
When the key is turned the slides are drawn in opposite directions, so that their
ends lie within the inner cylinder; the key is then, by the formation of one or other

page_text: of the slides, prevented from turning further within the cylinder, and the cylinder
being now free to rotate is turned by the slide into its unlocked position. This it
arrives at when it has made by preference one half turn, as the slides are then free
to be again forced outwards by their springs, and so disarranged when the key is
withdrawn.
The action of the key upon the slides is also peculiar, as compared with ordinary
tumbler locks; the peculiarity consists in so forming the slides and key that the
slides are brought to their unlocked position by less than a quarter turn of the key,
and it is therefore not the highest part of the key steps which act upon the slides,
but the ends of their sides which are rounded off. It is therefore very difficult to
make a duplicate or copy of the key from the original one, as the steps must not
only be of the same length as those of the proper key, but they must also be cor-
respondingly shaped as regards thickness and exact rounding off of all the acting
steps, and these are all made to vary.
In addition, the key has twice as many steps as there are slides, and all the steps
would have to be exactly copied, as there is nothing to shew which are the acting
steps and which are the false ones.
The opposite end of the inner cylinder to that which carries the slides forms an
obstruction to prevent the locking bolt (it may be of a safe door or other locking
bolt) from being pushed back, but when the inner cylinder is turned into its
unlocked position a hole or opening in the cylinder allows of the bolt being moved
back.
In some cases the tubular stem of the key may be bevilled at its end, so that
when the key is inserted into the lock its end may act as a wedge upon the slides,
and by slightly withdrawing them bring them to a position which will allow of the
central cylinder being turned from its unlocked position in the direction for locking
the lock; and then as the cylinder turns the slides complete their, backward move-
ment into the cylinder, the ends of the slides being so shaped as to allow of their
being so moved back. In this case a strong stop is employed to prevent the inner
cylinder from making more than one half turn, so that to unlock the lock the slides
must first be arranged by the key, as before described; or the ends of the slides
may be so formed that the slides have to be withdrawn by the key before turning the
cylinder either to lock or unlock.
The slides are notched at their sides, and the sides of the slits or openings in the
cylinders through which they pass are reduced to form a blunt vertical edge which
can enter the notches in the slides, and give a perceptable rise and fall to the slides
as they are moved to and fro. This motion is a sure protection or guard against
their unlocked position being ascertained by feeling.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Charles Chubb and George Hayter Chubb in the Great Seal
Patent Office on the 12th January 1878.
JOHN CHARLES CHUBB and GEORGE HAYTER CHUBB, both of No. 128, Queen
Victoria Street, St. Paul's, in the City of London. "IMPROVEMENTS IN LOCKS."
A communication from abroad by Theodor Kromer, of Freiburg, Baden,
Germany.
This Invention has for its object improvements in locks. For this purpose a
lock is formed of two cylinders, one, the outer one, fixed and forming part of the
lock case, the other capable of revolving within it, and carrying in its interior a
number of slides which lie across it one above the other, and project alternately
through slits formed in its two opposite sides, and enter corresponding slits formed
in the opposite sides of the interior of the outer fixed cylinder, thereby locking
together both cylinders by, as it were, a series of cross bars, which offer great
resistance to the lock being opened by force.
The slides are of the same length as the outside diameter of the inner cylinder,
and are acted upon by springs in such manner as to press the alternate slides
in opposite directions, and cause their ends to project from opposite sides of the
cylinder.
The pin, which serves as an axis for the key, stands up from the centre of the
inner cylinder, and the key is formed with steps or projections on two opposite sides
of its stem.
In the central part of each slide is a slot, against the sides of which the key acts.
When the key is turned the slides are drawn in opposite directions, so that their
ends lie within the boundary of the inner cylinder; the key is then, by the forma-
tion of one or other of the slides, or in other ways, prevented from turning further
within the cylinder, and the cylinder being now free to rotate is turned by the key
into its unlocked position. This it arrives at when it has made by preference one
half turn, as the slides are then free to be again forced outwards by their springs,
and so disarranged when the key is withdrawn.
The action of the key upon the slides is also peculiar as compared with ordinary
tumbler locks; the peculiarity consists in so forming the slides and key that the
slides are brought to their unlocking position by less than a quarter turn of the key,
and it is therefore not the highest part of the key steps which act upon the slides,
but the ends of their sides which are rounded off. It is therefore very difficult to
make a duplicate or copy of the key from the original one, as the steps must not
only be of the same length as those of the proper key, but they must also be corre-
spondingly shaped as regards thickness and exact rounding off of all the acting steps,
and these are all made to vary.
In addition, the key has twice as many steps as there are slides, and all the steps
would have to be exactly copied, as there is nothing to show which are the acting
steps, and which are the false ones.
The lower end of the inner cylinder is solid, and forms an obstruction to prevent
the locking bolt, it may be of a safe door or other locking bolt, from being pushed
back; but when this cylinder is turned into its unlocked position, a hole or opening
in its solid end allows of the bolt being moved back.
In some cases the tubular stem of the key may be bevilled at its end, so that
when the key is inserted into the lock its end may act as a wedge upon the slides,
and by slightly withdrawing them bring them to a position, which will allow of the
central cylinder being turned from its unlocked position in the direction for locking
the lock; and then as the cylinder turns the slides complete their backward move-
ment into the cylinder, the ends of the slides being so shaped as to allow of their
being thus moved back. In this case a strong stop is employed to prevent the
inner cylinder from making more than one half turn, so that to unlock the lock the
slides must first be arranged by the key, as before described; or the ends of the

page_text: slides may be so formed that the slides have to be withdrawn by the key before
turning the cylinder either to lock or unlock.
The slides are notched at their sides, and the sides of the slits or openings in the
cylinders through which they pass are reduced to form a blunt vertical edge, which
can enter the notches in the slides, and give a perceptible rise and fall to the slides
as they are moved to and fro. This motion is a protection or guard against their
unlocked position being ascertained by feeling.
Having thus described the nature of the Invention, we will proceed to describe
more fully the manner of performing the same.
above described.
Figure 1 is a front view of the lock; Figure 2 is a similar view, with the front
cover plate removed.
Figure 3 is a transverse section taken through the line 2, 2, Figure 1.
Figure 4 is a transverse section taken through the line 1, 1; the cover plate and
internal slides are removed in this Figure.
Figure 5 shews a front view of the lock, with the cover and all of the tumblers
but one removed.
Figure 6 shews a side elevation of the inner cylinder of the lock; and Figure 7, a
side elevation of the key.
In these Figures A is the outer cylindrical case, which can be secured, say, to the
door of a safe by screw bolts entering the holes A¹ in the enlarged flange, which
projects beyond the remainder of the case, as shewn ; B is the inner cylinder of
two different diameters fitting the interior of the cylinder A. The larger end of
the cylinder B is hollow, and receives within it a number of slides C, which lie one
above the other, as shewn at Figure 3. The opposite sides of this part of the
cylinder are notched or cut away for the ends of the slides to pass through, and
It is not
enter corresponding notches in the sides of the interior of the outer case.
essential that the exterior of the outer case should be circular, although it is con-
venient to make it for this form.
Each slide C has a spring C¹ secured to it; the outer end of the spring is made
into a small coil or bend, so that it may be held in one or other of the slotted under-
cut recesses D in the sides of the cylinder B, as shewn. There are two of these
recesses D, and they are on opposite sides of the cylinder. The slides are placed so
that their springs come alternately into the two recesses, the end of the spring of
one slide being held in one of the recesses D, whilst the ends of the springs above
and below it are held in the other recess D. By this means the alternate slides
are forced outwards in opposite directions to their springs.
It is not essential that the slides should be pressed outwards from both sides of
the cylinder, nor even that they should act alternately; they might be projected
outwards on one side only, or more of them on one side than on the other. I,
however, prefer that they should be projected outwards on both sides, as above
described.
The lower part of the cylinder B is solid, and around one half of its circumference
is a groove B¹, into which enters the end of a pin E carried by the outer case A.
A radial hole F is also formed into this part of the cylinder. The end of this hole
can be brought opposite to a corresponding hole G formed through the outer case A,
or can be turned away from it into the position shewn at Figure 3 of the Drawings;
so that the lower part of the cylinder then forms an obstruction to prevent a bolt not
shewn in the Drawings, from being drawn back. His a pin which stands upwards
from the centre of the cylinder B, and serves as an axis for the key. Standing up
from the solid bottom of the cylinder B is also a short stump I, against which the
key acts to turn the cylinder B from its unlocked into its locked position; J is a

page_text: cover plate by which the open ends of the cylinders A and B are covered; this plate
is held by screws K to the outer case A. The key is formed with stems or projections
on two opposite sides, as shewn at Figure 7. The end of the stem of the key is
also bevilled as shewn.
In order to unlock the lock the key is turned in a direction away from the short
stump I; the steps on the opposite sides of the key then act on the slides, and draw
them in opposite directions until, when the key has made, say, a quarter turn, they
all lie within the outer limit of the cylinder B. Two opposite steps of the key then
bear against one of the slides, by preference the lowest slide, as shewn at Figure 5,
and the key cannot turn further without carrying round this slide with it. The
slides and cylinder B are therefore turned by the key, and when the cylinder has
made one half turn it comes into its unlocked position, and cannot turn further, by
reason of the stop pin E. The ends of the slides, but in reversed position, are now
again opposite to the notches in the sides of the outer case A, and are pressed out-
wards by their springs, so turning the key backward a short distance, and
bringing the stepped projections on its end opposite to the keyhole in the cover
plate J, and allowing the key to be withdrawn. As the key is withdrawn the
slides or some of them are pressed outwards still further by their springs.
When the lock is to be again locked the key is again inserted, and its bevilled
end acting upon the slides withdraws them a short distance; the key is then turned
towards the short stump I, and bearing against it turns the cylinder; the slides then
move back into the cylinder, their ends being rounded off, as shewn, to allow of
their being moved back when turned in this direction. When the cylinder has
been turned into its locked position the ends of the slides have been brought opposite
to the recesses in the outer cylinder, and the slides are forced outwards, by their
springs, and prevent the cylinder from turning, and as they then project from two
opposite sides of the cylinder they lock and hold it as though a solid bar were
passing through the cylinder, and entering into the notches in the outer case.
By forming the lock and key, as above described, in such a manner that after the
lock has been unlocked the slides are moved a distance outwards on the withdrawal
of the key the lock cannot shift out of its unlocked position either by accident, as
for example, by any jar given to the door, or by the introduction of any kind of
key, so long as this key has not the same diameter of stem and bevilled end as the
proper key. The fact also that the key in unlocking the lock does not act directly
upon the inner cylinder to turn it, but only acts upon it by pressure against one or
more of the slides, adds greatly to the difficulty of opening the lock by a false key,
as the action of any key having any of its steps either a little too broad or too
high, or not rounded off at their ends to the same extent as the steps of the proper
key, would not properly withdraw the slides; and even if the slides were nearly
but not quite withdrawn into the inner cylinder by the key the key would force
them against the sides of the outer cylinder, and cause them to act as brakes and
prevent the inner cylinder from being turned. As before stated the edges of the
slides, where they bear against the sides of the notches or openings in the cylinders
(when the inner cylinder is attempted to be turned in a direction to unlock the
lock), have shallow notches, not shewn on the Drawings, formed in them; and the
side edges of the notches are brought to a blunt edge, as shewn at x, x, so that the
slides when moved endwise over these edges have a perceptible rise and fall given
to them, which prevents the correct position of the slides being ascertained by
feeling."
"
Having thus described the nature of the Invention and the manner of performing
the same, we would have it understood that what we claim is,-
First. The construction of locks, substantially as herein-before described.
Second. The construction of locks, substantially as described, with a cylinder
capable of turning in an outer case, and carrying transverse slides of a length equal
to the diameter of the cylinder, and with the slides pressed outwards by springs to
cause them to enter notches in the outer case when the cylinder is in its locked
position.

page_text: Third. The construction of locks, substantially as described, so that their slides
are brought to the unlocked position by the rounded off extremities of the steps of
the key, and not by the extreme ends of the steps as heretofore.
In witness whereof, I, the said John Charles Chubb, have hereunto set my
hand and seal, this Eleventh day of January, in the year of our Lord One
thousand eight hundred and seventy-eight.
J. C. CHUBB. (L.S.)