AN IMPROVED LOCK AND KEY, APPLICABLE TO VARIOUS PURPOSES
Year: 1815

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
MITCHELL, of Glasgow, Watchmaker, and JOHN LAWTON, of King Street, Snow
Hill, Manufacturer, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Seventh day of March,
in the fifty-fifth year of His reign, give and grant unto us, the said William
Mitchell and John Lawton, our exors, admors, and assigns, His special
licence, full power, sole priviledge and authority, that we, the said William
Mitchell and John Lawton, our exors, admors, and assigns, should and lawfully
might, during the term of years therein mentioned, make, use, excrcise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, our
Invention of "AN IMPROVED LOCK AND KEY, APPLICABLE TO VARIOUS PURPOSES;"
in which said Letters Patent there is contained a proviso that if we, the said
William Mitchell and John Lawton, or one of us, shall not particularly
describo and ascertain the nature of our said Invention, and in what manner
the same is to be performed, by an instrument in writing under our or one
of our hand and scal, and cause the same to be inrolled in His Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said Letters Patent, that then tho said Letters Patent,
and all liberties and advantages whatsoever thereby granted, shall utterly cease,
determine, and become void, as in and by the same, relation being thereunto
had, may more fully and at large appear.

page_text: NOW KNOW YE, that 'in compliance with the said proviso, we, the said
William Mitchell and John Lawton, do hereby declare that our said Invention
is for the purpose of making more secure the article commonly called a lock,
whether for doors, desks, boxes, &c., or any article to which locks are now
applied; and we hereby declare that our improvements which we have
invented consist of,-
Firstly, in making our wards, which the web of our key has to pass, move
or turn upon studs, pillars, or axes, by which means they are capable of
intangling any false key or instrument that may be applied to attempt the
opening of our locks; we therefore call ours a detecting lock.
Secondly, we have invented and do use, in combination with our moving
wards, a curtain or guard made of steel, iron, or any suitable material, which
always covers the key hole of our improved lock when it is single locked, by
which contrivance our locks will retain any instrument or false key capable of
lifting the tumblers of our locks, and consequently detect the means employed
in attempting to open our locks.
And we do hereby declare, thirdly, that we have invented and do use a
method of double locking our desk and box locks, by merely pressing down
the lid of either the desk or box to which they are fixed, by which improve-
ment much time is saved and greater security obtained, and this we effect by
making the hasps of our locks. press in their passage to the closed position
upon a short lover, which, acting on the short end of another lever attached to
the locking bolt, brings it forward to the double-locked. position..
י
And, fourthly, we declare that to permit our tumblers to slide out of the
notches into which they drop to 'secure our curtain and locking,bolt, we make
one side of each of our notches to form an angle of about forty-five degrees
with the upper line of the locking bolt, the notches thus made appearing
nearly like the notch formed between the teeth of a hand saw, one side only
of each notch being perpendicular to the upper line of the locking, bolt. By
referring to our Drawings, the same principle, it will be seen, is made use of in
the three notches of our steel curtain for desk and box locks, it being
necessary that the tumbler that secures it should slide out of the notches when
required.
And fifthly, we declare that we have invented, for the use of travellers and
all persons who may wish to possess the means of security, a new kind of
portable lock, which can be applied to the door of a room, closet, &c., more
readily than a common padlock, and possessing all the security that our
improved wards and curtain can give, being suited for all temporary or casual
purposes; and this desirable object we effect by screwing a hasp plate of iron

page_text: upon which three or more dovetails are firmly rivetted to the door, &c., or to
the door and frame; and to prevent the screws from being withdrawn the
under plate of our portable guard locks has three slits or grooves, which,
sliding under the dovetails in the hasp plate, permits the lock to come close up
to the hasp, where it may be locked and remain a complete security. And
we hereby further declare, that our portable guard lock is so contrived that it
can be fixed over the escutcheon of any lock to prevent the admission of any
key to a lock that may be already fixed until ours is unlocked and removed.
And we hereby further declare, that in the three annexed Drawings are
contained Figures of our improved wards, our guard, or curtain, and our
compound levers, which we use for effecting the double locking of our desk
and box locks; likewise a correct representation of our portablo lock for the
use of travellers.
Drawing No. 1.-Figure 1, A represents a plan of the locking bolt, with the
stud or pin a (commonly called a cock) screwed firmly to it, and the stud or
pin 6 rivetted to the bolt. Figure 2 is an edge view of Figure 1, with the
small studs c and d rivetted to the under side. These studs or pins take into
the slits e and f, see Figure 8 and 4, and by the motion of the locking bolt
they are turned on their centres. Figure 8, B represents a plan of the left-
hand moving ward, with its slit e, to receive the pin c of Figure 2. Figure 4,
C is a plan of the right-hand moving ward, with its slit f, to receive the stud
or pin d, Figure 2. Figure 5 is an edge view of Figuro 8, and Figure 6 an
edge view of Figure 4. Figure 7 represents the stud upon which Figure 5
turns, and Figure 8 shews-a similar stud for Figure 6 to turn on. Figuro 9
represents a plan of the under side of the upper moving ward D, with a pro-
jecting edge bar at 9 to receive the pressure of a spring. Figure 10 is an
edge view of Figure 9. Figure 11 shows the stud or axis upon which
Figure 10 turtis. Each of these studs have a small screw tapped into their
upper ends to keep the moving wards in their places. They are shown
separated from their places over each stud. Figure 12, E represents a plan of a
brass cylindrical case, which is fixed by two screws p and q to the back of the
external plate of the lock. This serves to inclose and cover the principal parts
of the moving wards, and has a hollow recess turned out of its upper surface to
contain a steel guard or curtaiti; part of the sides of this cylindrical case are
filed away to permit the locking bolt to pass or slide through and to freo other
parts of the lock. On the upper surface of the case E, exactly in the centre, is
fixed the pin h for our steel curtain to turn partly round upon. The guard or
curtain receives its motion or is turned round upon its centro by the stud or
cock a screwed to the locking bolt, Figure 1. The upper surface of the case

page_text: E is pierced to receive the key, as shewn at i, which pierced key hole is
connected with an aperture j, j, concentric with the axis h of the guard or
curtain.. Just above the centre pin A is an oblong aperture & pierced through,
which permits the stud a screwed to the bolt, see Figuro 1; to rise or come
through, and take into a slit. I, Figure 15, in the guard or curtain, which
guard or curtain is retained in a proper position by the square stud of the
tumbler m (see Figure 12), coming through the small opening at n, dropping
.into notches made in the steel curtain to receive it. To shew this more per-
fectly, see Figure 18. Figure 18 represents the under side of the case, Figure
.12, in which the tumbler m, and the apertures i, j, k, and n, may be observed.
Figure 14, E shews a section of the brass case, Figure 12, taken through the
line 1, 2, Figure 12, showing the depth of the recess for containing
the curtain or guard, and likewise the part of the side that is filed away
to give room for the locking bolt to pass. Figure 15, F shews a plan of the
upper side of the steel guard or curtain, with three apertures and the centre
hole pierced through for. purposes to be hereafter described. The centro
hole of the guard in large locks is furnished with a short pipe, which exactly
fits the centre pin fixed on the surface of Figure 12 at h, and turns freely
upon it, except when the stud m of the tumbler (see Figure 12) drops into
either of the notches 1, 2, or 3, in which case it is retained in its. position, nor
can it be turned until the tumbler (Figure 12 and 18) m is lifted the
key. Figure 16, F is a plan of the under side of the steel curtain, the
apertures being the same as in the view of the upper side, but in this Figure
the position of the ward G, fixed to the under side of the curtain F, and moving
with it, is distinctly seen. Figure 17 shews an edge view of the steel curtain,
with the same cylindrical pipe and moving ward G.
the key, the web or bit of which we have shewn in
likewise, as high up as the pin of the lock enters. We
explain the manner in which the various parts act in concert, so as to form a
sure detection of any attempt to open our locks, and we shall endeavour to
shew how nearly impossible it would be either to pick our locks by any false
key or instrument of any kind whatever, or to make a false key to the lock
by the more usual method resorted to of taking impressions from the wards
upon a plastic surface. Figure 19 represents a lock in the unlocked position,
with the brass case E and steel curtain F in its proper situation, taken off the
lock and placed under, that the position of the wards B, C, and D, may the
more plainly be seen, the ward G, fixed to the guard or curtain being shewn
in dotted lines at G, and the square stud m of the tumbler m, in the notch 3
of the steel curtain F. If in this state we conceive the case. E placed on the
Figure 18 represents
section, and the stem
shall now attempt to

page_text: lock.so that the pin o comes up through the key hole at i, and the stud
or cock a, coming up through the oblong aperture k, fits into the slit 1 of the
cartain F, it will be in a fit state to use the key to effect the first shoot of
the locking bolt. Figure 20 represents one of our.locks complete, with tho
case E placed on and the steel curtain in its place in an unlocked state.
The circular iron-plate Figure 28 is to be laid on the case over the steel
curtain, and screwed to the external plate of the lock by the same screws as
pass through the sides of the case at p and q, fixing the whole firmly together,
and covering the curtain very securely.. Figure 21 represents a plan of one
of our locks when the key has effected the first shoot of the locking bolt A;
the caso E, with its curtain F, being, removed and placed under, that the
position.of the moving wards B, C, D, and G, may be examined. If the four
wards are compared with Figure 20, it will be found that they have all
changed their positions, which.change has been effected by the following
means. The studs or pins c and a, fixed to the under side of the locking bolt
A, Figure 2, taking into the slits e and f of the wards B and C, keep them
immoveable, while the locking bolt A is kept in the same fixed state by its
tumbler r; but as soon as the key disengages the tumbler r from the locking
bolt it is carried forwards, and the studs c and d, taking into the slits e and .f,
turn the wards B and C upon the studs or axis s and t, and retain them firmly
in the position shewn in Figure 21, by means of the tumbler of the locking
bolt having dropped into the middle notch of the locking bolt A. The stud
or pin 6 in the locking bolt A is seen in Figure 19 in the hollow of the
ward D, but as this stud or pin (being fixed to the locking bolt A) must
more in a line. parallel to the direction of the locking bolt A; it follows, that
when the locking bolt is carried forward from the unlocked to the single
locked position, tho stud or pin 6 will bear on the more elevated point V of
the ward D, and depress it, the spring H (bearing on the edge bar:9) yielding
to the force applied to give motion to the locking bolt. When the key lifts
the tumbler m, the steel curtain is at liberty to move upon its axis h, and is-
turned partly round by the stud a, screwed to the locking bolt A, coming up
through the oblong aperture k in the brass case E, and taking into the:
slit of the curtain F. The passing of the locking bolt from the unlocked to
the single locked position, carries the curtain so far round upon its axis as to
permit the tumbler m to drop into the middle notch of the curtain at 2, .
placing the blank or guard part of the curtain before the key hole i. At the
same time the ward G, rivetted to the under side of the curtain, shown in
dotted lines in Figure 21, has come within the range of the key's web, forming
altogether such a number of obstructions as neither art or force can overcome,

page_text: .except such forco only as is capable of destroying the interior of any lock
altogether. Figuro 29 shews a plan of. one of our locks in a double locked
position; the case E, with the curtain F, being placed under, as in the preceding
Figures, gives the opportunity of showing that by the passing of the locking
bolt A to the doubled locked position, the wards B, C, and D, are completely
out of the range of the key, and the curtain F having been carried further
round till the tumbler m has dropped into the last notch 1, the key hole
in the curtain is brought to coincide with that in the .brass case E, permitting
the key to be withdrawn. By examining the position of the ward G. it.will
likewise be found out of the range of the key, so that although the web of
the key has had to pass them all, they are now (in the double locked as well
as in the unlocked position) quite clear of the web of the key in its range
round the pin o. We trust by what we have shewn in our Drawings, and by
this our Specification endeavour to explain, it will appear evident our locks
cannot be opened or unlocked by any instrument used for the purpose of
picking locks with, nor can impressions be obtained from the.wards upon any
plain surface introduced into the key hole for that purpose; as, for instance,
when our locks aro. double locked, the whole of the wards are placed out of
the range of the key or any instrument that can be introduced into the key
hole, and, admitting that a false blank key can be made that would lift both
tumblers, and effect the passing of the locking bolt from the double to the single
locked position, detection must inevitably ensue, as such instrument or blank
key would be completely fixed between the four wards B, C, D, and G. In
addition to which, the steel curtain being placed before the key hole, escape,
or, in other words, to withdraw the blank key, is impossible. Now we hereby
declare that although we give a preference to the method before described of
moving our curtains or guard so as to place it before the key hole of our locks,
the same effect may be produced by various ways, too numerous for insertion
in a Specification.
'
Drawing No. 2.-Figure 1, D shows a plan of the upper side of a small
catch piece or lever, which turns partly round upon a sunk screw, that fits into
the centre hole a, and is tapped into the main plate of the lock. Figure 2, B is
a plan of the second lever moving or turning upon a sunk screw, fitted into tho
hole b, and tapped into the main plate of the lock. The longest end of this
lover terminates in a small loop. c to receive a pin a, Figure 8, attached to the
projecting arm 6 of the locking bolt. Figure 3. shows à plan of the upper
side of the locking bolt for one of our desk or box locks,' with one side of the
notches or rack, e, f, g, that the tumblers drop into, filed to an angle of about
forty-five degrees with the upper line of the locking bolt. The bolt for this

page_text: kind of lock has a projecting arm at h, furnished underneath with a short stud
or pin d, which, when the lock is put together, moves in the slit or loop c'of
the second lover B, Figure 2. Figure 4, C represents a plan of one of our
desk hasps, the end of the loop k being filed a few degrees from the right
angle; this acts as a wedge or inclined plane upon the projecting catch I of the
lever D, Figure 1, in its descent to the double locked position. Figure:5, C
represents a side view of the hasp, having a small recess or hollow m to receive
the end of the catch I of the first lever D after the double locking has
been effected. Figure 6 represents a plan of a fragment of the main plate of
the lock, with the positions of the levers B and D when the bolt is in the
unlocked position, the inclined part of the hasp at k (represented in section)
being placed in its proper situation to pass and effect the double locking of the
bolts. Figure 7 shews a similar fragment of the main plate, with the levers
D and B in the position they assume when brought to the double locked
position. This is effected by the inclined part of the hasp at k having in its
passage pressed so hard upon the catch or projection I of the lever D that it
has driven back the end o of the lever B, and brought the loop e forward on
the contrary direction from r to s. Figure 8 shews a plan of one of our desk
locks, with the curtain F and upper plate G removed, that the pin'd of the
arm h may be seen in combination with the loop c of. the lever B. The bolt
in this Figure is in the unlocked position, therefore the parts of the levers D
and B that can be seen correspond in position with Figure 6. Figure 9
represents a plan of the same lock, when the hasp with its inclined plane k
(see Figures 6 and 7) is supposed to have passed the catch I of the lever D,
and has effected the double locking of the bolt. To shew how this has been
performed, suppose the inclined plane of the hasp C (see Figures 4, 5, 6,
and 7,) to be pressed firmly upon the point I of the lover D, such pressure
would turn it upon its screw a, and the point or end n would press firmly
against the lever Bat o, causing it to turn upon its screw 6 and bring the loop c
forward to the double locked situation at s (see Figure 7). Now the loop c
of the lever B-having hold of the short stud a, attached to the arm h of the
locking bolt, will bring it forward to the double locked position; the tumbler
p of the locking bolt and 9 of the curtain F sliding out of their notches or
racks, which they are enabled to do, the one side of each at e, f, and g, being
filed to an angle of about forty-five degrees with the upper line of the locking
bolt for that purpose. This lock will be equally secure with the others when
locked, as no art can effect the return of the locking bolt to the unlocked
position without the use of the proper key. To prevent the lever D from
being drawn out of its place by the return of the hasp, the small spring t is

page_text: for the purpose of throwing it back, and keeping it at all times in a.proper:
situation to meet the.hasp loop.-
Traveller's. Lock.-Drawing No. 3.-Figure 1,. A represents an. edge.view->
of part of a hasp plate. B, B, are the loops or staples; and C, C, C, three screw
holes. Figure 2, A, D, shews a plan of the hasp plate divided into two parts,. 5
but which can be united by the dovetail E. .F, F, F, F, are screw holes to fix:
it to door, &c. G,.G, G, are dovetail studs rivetted.to.the plate, and H is an A
aperture. to. admit: the_brass: escutcheon of. a key hole to lay in. Figure.3:
represents. the under plate of the lock, which is applicable to the plate .:A, D; .
when: united. The dovetail.slits I, I, I; pass under the dovetail studs.1
G, G, G.. Figure 4: represents the hasp plato united and screwed. firmly to
the fragment of a door and part of tho. door frame; the part A screwed.to the:
frame remains fixed when the door is opened, the: part D being fixed to the
door goes with it, but returns to the proper situation to receive.the lock when
the door is shut close. Figure 5 represents a part of a door and frame with 1
our lock slid under the dovetail pins G, G, G, of the hasp plate until the loops >
B and B have entered the lock, where they are retained by double locking the..
bolt. When the lock-is wanted to be removed it may be unlocked and drawn.
from under the dovetail studs with perfect ease... Should it be required to fix :
this lock to a door that shuts flush with the frame, the part A. of the hasp 2
pláte may be screwed to the frame. by the screw holes. K, K, K, and the
other part fitted to it by the dovetail, as before: described. The manner of.
fixing it over the escutcheon of any key hole.will be too obvious.to-need.
explanation. We have not.in the traveller's lock shewn any of the wards or..
internal parts which we make use of.to effect the locking of the bolt, .the
principle being the same as in the two locks already described, the. object here.
being to attach our improved principle to a temporary inode.of fixture, there:
being. no form of lock intended for security to which our principle is not.
applicable.
25
To conclude, we hereby declare that we do not claim as our Invention the g
various parts represented in our Drawings common to all locks, such as bolts,
tumblers, &c.; but we hereby declare that we have only introduced them to
explain how our improved moving wards, curtains, or guards, and compound
levers, &c., are attached, to effect the desirable purposes of security to pro-
perty, and detection of the means employed in attempting to open our locks.
In witness whereof, I, the said 'John Lawton, have hereunto set my
hand and seal, this Sixth day of September, in the year of our Lord
One thousand eight hundred and fifteen.
85
JOHN
(L.B.) LAWTON.

page_text: AND BE IT REMEMBERED, that on the Sixth day of September, in
the year of our Lord 1815, the aforesaid John Lawton came before our said
Lord the King in His Chancery, and acknowleged the Specification afore-
said, and all and every thing therein contained and specified, in form above
5 written. And also the Specification aforesaid was stampt according to the
tenor of the Statute made for that purpose.
'Inrolled the Sixth day of September, in the year of our Lord One
thousand eight hundred and fifteen.