THE SAFEGUARD TO LOCKS, APPLICABLE TO LOCKS IN GENERAL, BY WHICH THEY MAY BE SO SECURED AS TO DEFY THE ATTEMPTS OF PLUNDERERS USING PICKLOCKS OR FALSE KEYS
Year: 1817

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of the City of Bath, Esquire, send greeting.
WHEREAS His present Majesty King George the Third, in and by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eighth day of February last, for Himself, His Leirs, and suc-
cessors, did give and grant unto me, the said William Clark, His especial
licence, full power, sole privilege and authority, that I, the said William
Clark, my exors, adñiors, and assigns, and every of them, by myself and them-
selves, or by my and their deputy or deputies, servants or agents, or such
others as I, the said William Clark, my exors, adfiiors, or assigns, should at
any time agree with, and no others, from time to time and at all times there-
after, during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, and also in all His Majesty's Colonies and Plantations
abroad, my said Invention or contrivance, to be called "THE SAFEGUARD TO
LOCKS, APPLICABLE TO LOCKS IN GENERAL, BY WHICH THEY MAY BE SO SECURED
AS TO DEFY THE ATTEMPTS OF PLUNDERERS USING PICKLOCKS OR FALSE KEYS;"
in which said Letters Patent there is contained a proviso obliging me, the said
William Clark, by an instrument in writing under my hand and seal, parti-
cularly to describe and ascertain the nature of my said Invention, and in what
manner the same is to be performed, and to cause the same to be inrolled
in His Majesty's High Court of Chancery within two calendar months next

page_text: and immediately after the date of the said recited Letters Patent, as in and
by the said recited Letters Patent, reference being thereunto had, will more
fully appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Clark, do hereby describe and ascertain the nature of my said Inven-
tion, and in what manner the same is to be performed, by the Drawings
hereunto annexed, and the-following description thereof (that is to say):-
My safeguard to locks I propose to consist,―
First, of a screen or scutcheon, with several moveable indexes or dial plates
covering the works of a lock of any or the common construction, and in the 1
most eligible part of this screen or scutcheon a plug capable of being drawn
out or unscrewed, for the purpose of discovering or obtaining access to the
keyhole.
Secondly, behind the screen or scutcheon, and connected with the moveable
indexes or dial plates before mentioned, I place segments of circles, which fit 1
into a corresponding groove or grooves in the plug and act as bolts, preventing
it from being unscrewed or drawn out.
Fig. 1 represents the screen or scutcheon with any number of moveable
indexes or dial plates A, A, A, A, and in the centre or any other convenient
part the plug piece B is placed, immediately over the keyhole of the 2
within lock.
.
Fig. 2 represents the back of the screen or scutcheon, with segments of
circles A, A, A, A, as before expressed, attached to and moving with the
indexes or ilial plates in the front view. In the centre (or elsewhere, as before
'expressed,) is the plug B, with a groove or grooves in the cylindrical part 2
into which these segments work, and thus confine or prevent the plug B from
being removed or drawn out, unless the concave part of the segments are all
turned so as to correspond with and clear the plug. The contrivance and
action of the safeguard is this:-Having secretly determined any letters or
association of letters to correspond with any number or mark upon the plate 3
in front, adjust and fix the parts of the segments to correspond with and
clear the cylindric plug (these segments being moveable upon their arbours and
to be fixed by a nut and screw). This adjustment being effected, move the
indexes away from their secret adjustments, and with each index its accompany-
ing segment behind will turn and be thus passed into the groove of the plug, so 3.
that the plug becomes confined and cannot be drawn out until the indexes are
again set to their secretly determined marks, which will bring the concave part
of each segment to correspond with or clear the plug, when the plug may then
be drawn out and access obtained to the keyhole of the lock.

page_text: It is only necessary to add, that I do not confine myself to the precise cha-
racter of siguals, as letters, numbers, &c. which shall occupy the dial plates
or indexes, but leave that entirely variable, at the choice or taste of the manu-
facturer; neither is the form of these pieces which I have called segments,
nor the plug piece, confined to that of the circular, but may be also of various
angular forms, observing that the part of the segment described as concave
must be such as to correspond with the form of the plug piece (whatever that
may be), so as to stand perfectly free of it when placed in the position for
drawing out the plug. Nor do I confine myself to any materials of which to
manufacture the same, but adopt such articles as circumstances may render
most eligible.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Third day of April, in the year of our Lord One
thousand eight hundred and seventeen.
Inrolled the Fifth day of April, in the year of our Lord One thousand
eight hundred and seventeen.