CERTAIN IMPROVE- MENTS IN LOCKS, AND FOR FASTENING AND SECURITY
Year: 1833

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES.
CHUBB, of Saint Paul's Churchyard, in the City of London, Patent Detector
Lock Manufacturer, for myself and for EBENEZER HUNTER, of Wolverhampton,
in the County, of Stafford, Locksmith, send greeting.
WHEREAS we did, by Petition, humbly represent to His most Excellent
Majesty King William the Fourth, that we had invented "CERTAIN IMPROVE-
MENTS IN LOCKS, AND FOR FASTENING AND SECURITY," which we believed would
be of general benefit and advantage, and that we were the true and first
Inventors thereof; and thereupon His said Majesty, being willing to give
encouragement to all arts and inventions which may be for the public
good, was graciously pleased to issue His Royal Letters Patent under the
Great Seal of Great Britain, bearing date at Westminster, the Twentieth
day of December last, in the fourth year of His reign; and by those Letters
Patent His said Majesty did, for Himself, His heirs and successors, give and
grant unto us, the said Charles Chubb and Ebenezer Hunter, our executors,
administrators, and assigns, His especial licence, sole privilege and authority,
that we or they, by ourselves or themselves, or by our or their deputies,
servants, or agents, or such others as we or they should at any time agree
with, and no others, from time to time and at all times during the term of
fourteen years from the date of the said Letters Patent, should and lawfully
might make, use, exercise, and vend our said Invention, within England,
Wales, and the Town of Berwick-upon-Tweed; and whereas the said
Letters Patent also contain a proviso obliging us, the said Charles Chubb

page_text: and Ebenezer Hunter, particularly to describe and ascertain the nature of our
said Invention, and in what manner the same is to be performed, by an instru-
ment in writing under our hands and seals, or the hand and seal of one of us,
and to cause the same to be inrolled in His Majesty's High Court of Chan-
cery within six calendar months after the date of the said Letters Patent.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Chubb, for myself and for the said Ebenezer Hunter, do hereby
declare that the nature of our said Invention, and the manner in which the
same is to be performed, is described and ascertained in manner following,
and by the aid of the three Sheets of Drawings hereunto annexed, that is
to say:
Our said improvements in locks used for fastening and security are carried
into effect by arranging and forming those parts which are commonly called
tumblers (for detaining the bolt from being moved) in such manner that the said
tumblers will admit of applying the springs by which they are to be urged
towards the key in a suitable direction for acting near to the centre pin or
stud about which the tumblers are moveable; but the direction in which the
springs are disposed, together with the arrangement and form of the tumblers,
renders the lock so compact, that what is called a detector for detecting and
frustrating any attempt to pick open the lock can be very readily applied, and.
in a very simple and effectual manner, as herein-after described, to the said
tumblers, without increasing the quantity of workmanship, and consequent
expence of the lock, in so great a degree as in the detector locks which have been
heretofore made by me, the said Charles Chubb, according to certain improve-
ments in the construction of locks for which Letters Patent were granted to
Jeremiah Chubb by King George the Third, dated the Third day of February,
One thousand eight hundred and eighteen, and also according to an improve-
ment in the construction of locks for which a Patent was granted to me,
the said Charles Chubb, by King George the Fourth, dated Fifteenth of June,
One thousand eight hundred and twenty-four, and in the two Specifications
which were inrolled in pursuance of the said Letters Patent respectively, the
nature and invention of the locks which have since become known in trade
by the name of Chubb's Patent Detector Locks is fully set forth, and the
same consists in adding within a tumbler lock a detecting dettent or catch,
which is capable when brought into action of latching and detaining the bolt
of the lock from being withdrawn or unlocked, but which detector dettent
will (by the tendency of a suitable spring) always remain out of action, so as
to offer no impediment to the withdrawing of the bolt, unless some one of
the tumblers of the lock have been overlifted or raised higher than the true

page_text: key is intended to raise the same, which overlifting can never happen except
on an attempt to violate the lock by the introduction of a picklock or false
key; but on any one of the tumblers being thus overlifted it will bring the
detector dettent into action, so that it will latch and effectually detain the bolt
of the lock from being withdrawn; and after the detector has been so brought
into action it will be kept in action by a new and contrary tendency of its
spring, and then the lock is detected or deranged so that it cannot afterwards
be unlocked even by the ordinary unlocking action of the true key; and it
by the impediment to that usual unlocking action of the true key that the
owner thereof will have information that an attempt has been made to pick
open the lock, or to unlock it by a false key, and he must either employ another
key expressly provided for undetecting, or else he must practise some parti-
cular manipulation of the true key, in order to undetect or throw the detector
out of action, and put the lock into a condition to be opened by its own true
key; and as the movement whereby the detector can be so thrown out of
action requires the tumblers of the lock to be first put into a suitable
arrangement, there is all the same difficulty opposed to undetecting, by
picklocks or false keys, as there would to opening the lock by such means, and
it must be undetected before it can be opened. And for the more complete
explanation of our said improvements, I will first explain, by the aid of the
Drawings hereunto annexed, the structure of the locks without a detector.
In Sheet 1, Figures 1 to 10 inclusive represent a door lock of the kind called a
rim lock. A, A, is the plate turned up at the front edge B, through an opening
in which the end of the bolt 2 passes. D, D, is the raised rim to inclose the
works of the lock, and 3 the cover plate. a is the centre pin for the key;
c is the centre pin or stud upon which all the several tumblers 4, 5, 6, 7, and 8
are mounted as their common centre of motion. It is fixed fast into the
plate A, A, and projects outwards therefrom, and passing through a slit W,
in the tail of the bolt 2, serves as a stud to guide the sliding motion of the
bolt. The upper end of the pin may project up through all the tumblers, and
enter into a hole in the cover plate 3, in order to give the utmost support to the
pin c. The different tumblers are represented separately at Figures 4, 5, 6,
7, and 8; they are small round plates of metal, like pieces of money, with holes
cut out in them to receive the stud, and which projects up from the bolt 2. 9
is the spring, which is a piece of steel plate, cut with slits in the manner of a
comb, in order to divide the acting end into as many distinct springs as there
are tumblers. Although the fixed end is all in one piece, and that end is
secured to the plate A, A, of the lock by rivetting or otherwise, the steel
spring may be fixed by inserting the solid end of it into a notch in a stud

page_text: which is fastened to the plate by a screw, the spring being fastened into the notch
by a cross pin. When the spring is so fixed each portion of its divided end acts
against the edge of one of the tumblers with a tendency to turn that tumbler
round about its fixed centre pin, and towards the centre pin a of the key.
When the bolt is either locked or unlocked the stud d of the bolt will occupy
either the outermost k or the innermost of the wide parts of the openings
in the tumblers, and in either case when the key is removed from the lock
all the tumblers will arrange themselves so that their round edges will conform
one with another, as shewn in Figure 1, and no examination which can be
made of the tumblers through the keyhole will give any information as to
which of the steps in the key 10 are to be longer or which of them are to be
shorter than the others. When the key, Figure 10, is inserted and turned
round about its centre pin a, the bit of the key will act by its several steps,
marked 4, 5, 6, 7, and 8, in Figure 10, against the edges of all the different tum-
blers at once, and by raising each one a different but equally determined height,
according to the form of the said several steps in the bit, the narrow middle
parts m of the different notches in the tumblers (which narrow parts join the
outermost wide parts % of the notches to the innermost wide parts (,) are all
brought precisely to conform one with another, and to correspond with the
stud d of the bolt; and when the key has been turned far enough to produce
that effect, the lower steps 2 of the bit of the key, in its turning motion,
will then come to act against one or other of the edges of the notch n in the
bolt, and will shoot the same either backwards or forwards, according to the
direction in which the key is turned; and in so shooting the stud d of the bolt
will pass through the narrow middle parts m of the notches; but if the
tumblers are not all correctly raised to an exact conformity of their narrow
notches m with the stud d, the bolt cannot be moved, for any one tumbler
which is lifted too high, or which is not lifted high enough, will detain the
stud d, and prevent it or the bolt from moving at all.
Figure 11 represents a drawer lock of a similar construction, drawn full
size; the principal parts being marked with the same letters and figures for
reference as the preceding Figures, the above description will explain.
The rim D, D, for enclosing the works, is made in one piece with the cover-
plate 3, and when the screws for fastening the cover-plate are removed the
rim comes off with it.
Figures 15, 16, Sheet 2, represent a small padlock of a similar construction
with four tumblers; it is drawn the real size, and shews that the compactness
of the construction permits a lock of very great security to be made in very
small dimensions.

page_text: Figures 17, 18, 19 represent a lock on a similar construction, adapted for a
portfolio; it is drawn full size, and contains four tumblers; and the application
of a detector to locks of the aforesaid construction may be made according to
our present improvements in a very simple mode, by fixing a small hooked
spring detector within the lock in a suitable position to present its hooked end
to one of the tumblers, which tumbler has a notch cut into its edge in such
a position that if the said tumbler is ever overlifted or raised higher than its
proper position for allowing the bolt to be moved, the said notch will be
caught and detained by the hooked end of the spring detector before men-
tioned, so as to detain that tumbler in its overlifted position; and whilst so
detained that tumbler will necessarily detain the bolt of the lock from being
moved, and in that case the lock will be detected by the said spring detector, and
the usual action of the true key will not unlock the lock when so detected,
because it can have no operation upon that tumbler which has been over-
lifted, and which is kept so overlifted by the detector spring; and the
owner of the true key, by finding that it will not unlock the lock, will be
advertized that some attempt has been made to violate the lock by insertion
of picklocks or false keys. And in order that the overlifting of any one of the
tumblers may produce detection, that tumbler before mentioned on which the
detector spring is to operate has a stud pin affixed into it and projecting from
it so as to stand opposite to the edges of all the other tumblers, being received
into suitable notches cut in those edges, so that the said stud pin will have no
interference with any of the other tumblers during their ordinary action in
locking or unlocking the bolt by the true key; but on any extraordinary action
upon the tumblers by false keys or picklocks, any one of the tumblers being
overlifted will come to act against the said stud pin so as to overlift that
tumbler to which the said stud pin belongs, and cause that tumbler to be
caught and detained by the hooked end of the spring detector in the same
manner as if the overlifting action had been applied to that tumbler itself by
false keys or picklock as above supposed. And whenever the lock has thus
become detected, the spring detector cannot be released or disengaged so as to
undetect or set the lock free by any other means than by overshooting the main
bolt by the key a little further than its usual extent of throw for ordinary
locking. But as all the tumblers concur in preventing such overshooting, by
opposing the motion which the stud of the bolt must have in so overshooting,
the tumblers require to be all arranged by the key into a particular position,
and then other undetecting notches, which are cut in the tumblers at a suitable
place in each one for admitting the stud of the bolt during the said over-
shooting of the bolt, will come to a conformity with the said stud, and as soon

page_text: as the key has turned so far as to lift the tumblers to that conformity, but not
till then. The bit of the key in turning a little further forwards will act in a
second notch in the bolt, and produce the requisite overshooting of the bolt,
and thereby a small projecting part of the bolt will advance so far towards the
spring detector as to come in contact therewith, and bend the same away from
the tumblers until its hooked end is taken out of the notch of that tumbler
which it had previously detained in its overlifted and detected state; and the
instant that the said tumbler is so released from the spring detector its own
tumbler spring will cause it to drop down from its overlifted position, after
which the key, being turned backwards, will carry back the bolt from its over-
shot position, leaving the lock undetected and prepared for being opened with-
out obstruction by its true key. And note, in order to admit of overshooting
the bolt for the purpose of undetecting as aforesaid, the said undetecting
notches require a somewhat different position to be given to the tumblers from
their ordinary position for shooting the bolt in locking or unlocking, but,
nevertheless, the true key will produce that different position of the tumblers,
because for overshooting the bit of the key will meet the talon of the bolt, and
begin to overshoot before the key has been turned round so far and has lifted
the tumblers so high as the same key must be turned in ordinary locking to
raise the tumblers, and begin to act upon the bolt for shooting the same
forwards. And note, if it is preferred, a different key may be made for
undetecting, with the steps in its bit differing from those of the true key, in
which case the undetecting notches in the tumbler must be cut suitably to the
arrangement of the tumblers which that key will produce.
Figures 12 and 13, Sheet I., represent a door lock on a construction very
similar to that which is represented in Figures 1 to 10, but with a detector
added to it, and its several parts being marked the same letters and characters
of reference the previous explanation is nearly sufficient.
P is the spring
detector fixed at one end into the lock plate A, A, and its hooked extremity
applies to the edge of the tumbler 6, which is the detecting tumbler, and has
a notch P in its edge; and if ever that tumbler is overlifted the hooked end of
the spring detector P, by dropping into that notch, will detect the lock by
detaining that, tumbler in its overlifted position. q is the stud pin which is
fixed in the same detecting tumbler 6, and which pin projects upwards and
downwards therefrom so as to occupy the notches r in the edges of the other
tumblers 4 and 5, which are placed above the detecting tumbler 6, and also
other like notches r in the edges of the other tumblers 7 and 8, which are
placed below the detecting tumbler 6; and by means of the said stud pin 7 in
the detecting tumbler, and the notches r in all the other tumblers, any one of

page_text: And in order
the tumblers being overlifted will cause the overlifting of the detecting
tumbler 6, and its consequent detention in that overlifted state, by the spring
detector P. But note, it is not necessary that the middlemost tumbler 6
should be made the detecting tumbler, for the spring detector P may be
applied to the edge of any one of the tumblers in which a suitable notch p is
made, and in which a stud pin q is fixed to project so much as to stand opposite
to the edges of all the other tumblers in their respective notches r. R is a
guard which is fixed fast into the lock plate A, and rises up to the cover
plate 3; its end reaches over the bolt so as to stand close to the edges of all
the tumblers, but without touching them. Its use is to prevent any pricker
being introduced so as to disengage the spring detector P.
to disengage the spring detector P when it has caught the notch p of
the detecting tumbler, and detected the lock, a small lateral spur projects
downwards from the hooked extremity of the spring detector P towards
the lock plate A, A, so as to stand in the way of a small protection
v of the bolt 2 (see the separate Figure thereof); and when the bolt is
overshot beyond its usual extent of throw for ordinary locking, as herein-
before described, the said projection v will bend the spring detector P away
from the tumbler, and remove its hooked end from the notch p of the detecting
tumbler. is the second notch in the bolt wherein the key acts in order to
overshoot the bolt for undetecting, n being the notch before described, in which
the keys acts for ordinary locking and unlocking. The additional notches before
mentioned, which are cut in the tumblers in order to permit of overshooting
the bolt as much as is requisite for undetecting, are marked y in the separate
Figures of the tumblers, and they are adapted to receive the stud d of the bolt
when it is so overshot. And note, the notch y, in the detecting tumbler 3, must
be cut so wide as to permit of the requisite overshooting of the bolt when that
tumbler is detained is an overlifted state by the spring detector.
Figure 14, Sheet I., represents a box lock drawn full size. It contains four
tumblers and a spring detector, constructed and applied very nearly in the
same manner as the door lock, Figure 12 and 13, already described; but
Figure 14 shews that our improvements can be applied to very small locks.
The spring detector P is placed in a different direction, so as not to require to
be hooked at the end, but nevertheless its action is just the same as before
described.
Figure 20 and 21 represents a padlock drawn full size, to explain the appli-
cation of our improvements thereto. It contains five tumblers and a spring
detector P, constructed and applied very nearly in the same manner as herein-
before described. And another part of our improvements consist in rendering

page_text: locks of the kind herein-before described capable of a double security when
required by the use of an additional key, which will shoot or throw the bolt a
second time after it has been locked in the usual way by its ordinary key, the
said additional key having the steps in its bit quite different from those of the
ordinary key, so that the latter will not lock or unlock the bolt through its
second or additional throw, neither will the additional key lock or unlock the
bolt at its first throw. And this duplication of security is obtained without
any additional parts except the additional key, or any increase of com-
plexity in the mechanism of the lock, merely by giving suitable forms to
the same parts as have been herein-before described. A door lock of this
kind is represented at Figures 22 and 23, Sheet III., with the principal
parts detached, and the same letters and characters of reference are used
as in the former Figures to denote the same parts the preceding description
will apply. The several tumblers 4, 5, 6, 7, and 8 are elongated to an oval
shape, in order that each one may contain another narrow parts of the
opening k, l, m, which is cut out in it, and also another wide part t of the
same opening, both which parts s and t are farther from the centre pier c of
the tumblers than the openings k, l, m, which are the same as those previously
described. The additional narrow notches s are to permit the stud d of the bolt
to pass whilst it is throwing its second shoot by the action of the additional
key, and the said notches s are cut so as to require quite a different position to
be given to all the tumblers from that which will bring the other narrow parts
m to conformity with the stud d of the bolt, as is done by the ordinary key,
which, after having raised the tumblers to that conformity, then acts in the
notch n of the bolt to lock it the first shoot; but the additional key is suitably
formed to raise all the tumblers so as bring their narrow notches s to con-
formity, and having produced that conformity to act in the additional notch N
of the bolt, in order to throw the same its second shoot, which being done, and
the key turned round in order to withdraw it, the tumblers descend so as to
include the stud d of the bolt within the outermost wide parts d, and thereby
detain the bolt in its completely locked state under the joint security of the
detector and of two different keys, for the additional key must be first used to
unlock the outermost shoot of the bolt, and then the ordinary key must be
applied to unlock the other or ordinary shoot. The spring detector P is
exactly the same as before described respecting the other locks, and y are the
notches in the tumblers to admit the stud d of the bolt when it requires to be
overshot beyond the ordinary extent of its second shoot, so as to bring the
projection of the bolt in contact with the spring detector P in order to
undetect the lock, as herein-before described; and x is the notch in the bolt

page_text: wherein the additional key acts to produce such overshooting. And note, as
locks which throw the bolt through two successive shoots with the same key
are in common use, this part of our improvements is confined to the double
security which is given to the kind of locks herein-before described, by locking
a second time or shoot of the bolt by an additional key, which is quite different
from the ordinary key, that double security being further secured by a detector ;
and the chief proprietor of such a lock may have one double-ended key, which
will serve the purpose of both keys by using one or other end of it, and he
need only entrust his confidential agents with an ordinary key, which of itself
will lock up with as great a security as any locks heretofore commonly used;
but nevertheless he can at any time lock up all his locks a second time with his
own additional key, which he need never to entrust to any other person; and the
same additional key may serve for the additional locking up of any number of
locks which require a variety of ordinary keys for use by as many different persons.
In fact, a lock constructed according to this part of our improvements possess
every security which can be attained by applying two distinct locks to secure
the same door or drawer. And another part of our said improvements is a
mode of applying a seal of wax suitably imprinted, so as to secure the external
escutcheon or sliding cover which is provided for closing the keyhole of any
lock of the kind herein-before described, in such manner that the said seal
must of necessity be broken and defaced before the keyhole can be any way
examined or opened at all, either for the insertion of any key or for picklocks,
the said wax seal being applied within a cell, which is afterwards inclosed
by a suitable door, having such apertures through it as will permit a clear
view of the seal to shew whether it remains whole or is broken, but which
will effectually prevent any such access to the said seal as would be requisite
in order to obtain any impression therefrom for the purpose of fabricating a
false seal after having broken the true one.
And the said door, after being
closed in order to shut up the seal, is kept closed by an internal spring catch,
which has no communication whatever from the outside of the lock, and
which can only be released, or the door opened, by unlocking or withdrawing
the bolt of the lock; and to do that the keyhole must be first opened, but in so
doing the seal will be broken and defaced, and that will shew that the keyhole
has been opened.
Figures 25, 26, 27, Sheet III., represents a padlock so constructed. The
internal works, Figure 25, are same as those of the padlock represented in
Sheet II., and herein-before described, and spring detector may be applied as
herein-before described, but any other kind of internal lock works may be used.
G is the keyhole, and H is the usual sliding cover to shut the keyhole

page_text: perfectly. h is a blunt knife which is fixed into the said sliding cover H, and
projects out laterally therefrom so as to pass over the extreme surface of the
cover-plate of the padlock at the place where the seal of wax K is intended to
be applied thereon at the side of the keyhole G, suitable indentations being
punched into the metal at that place to enable the wax to adhere thereto; and
it is obvious that if such a seal of wax is applied when the slider H of the
keyhole is down, and has closed the keyhole G, that the slider H cannot
be slided up so as open the keyhole without breaking up and defacing
the seal by the said blunt knife h. The place where the said seal K is
to be so applied is surrounded by a raised rim M, Figure 27, which is part
of the cover-plate of the lock (or is firmly fastened thereto), forming a
cell suitable for the reception of the seal K, and N is the door by which
the said cell is inclosed. It is fitted with a hinge joint n to the upper
part of the cell, and a spring m is applied withinside of the door N to
cause it to fly open of itself when it is left at liberty; but when it is closed a
hooked catch p, which is affixed to the inside of the door N, is caught by an
internal spring catch d, which is applied within a cavity. The thickness of
the cover-plate and the catch d, g, is moveable about a centre pin by the action
of a spring e, so that it will of itself catch and fasten the door N when the
same is shut after the seal K had been applied. O is a circular opening in
the door N, of a sufficient aperture to give a full view of the seal when it is
shut up
within the cell, but solid cross bars are left across the opening O to
prevent access to the seal; or, instead of those cross bars, a glass may be
applied at the inside of the door N to cover the opening therein, and the tail
g of the spring catch d, g, extends to the inside of the lock through its cover-
plate into a suitable position to be intercepted by a stud R, which projects
out from the bolt 2 of the lock, as shewn in Figure 25, in such manner that
whenever the bolt is shot or locked the stud R will quit the tail g of the
catch d, g, leaving the same quite at liberty to latch by the action of the
spring e, in order to fasten the door N after the keyhole has been closed by
the slider H, and the seal has been applied; and after that the catch d, g,
cannot be released in any way except by the unlocking and withdrawing of
the bolt, and then the stud R thereof will press the tail g, and remove the
opposite end d out of the way of holding the hooked tooth p of the door N,
which will immediately fly open by its spring m.
Having now described our said improvements in locks used for fastening
and securities, I, the said Charles Chubb, for myself and for the said
Ebenezer Hunter, do hereby declare that the Invention whereof the exclusive
use is granted to us by the said Letters Patent consists in that simplified

page_text: form and arrangement of the parts of the locks herein-before described, which
renders the same suitable for the application thereto of the simple kind of
detector herein-before described, whereby all the properties and advantages of
the more complicated detector locks heretofore manufactured are attained, but
with much less workmanship and cost.
Also in the mode herein-before described of giving to such simple detector
locks the additional security of double-locking by an additional and different
key, without any complexity or great increase of workmanship.
And, lastly, in the mode herein-before described of applying a seal to
secure the keyhole of a lock from being opened without detection by the
breaking of the seal.
In witness whereof, I, the said Charles Chubb, have hereunto set my
hand and seal, this Twentieth day of June, One thousand eight