AN IMPROVED SPRING, ESPECIALLY. APPLICABLE TO THE JOINTS OF KNIVES, RAZORS, SCISSORS, AND OTHER LIKE ARTICLES
Year: 1855

page_text: LETTERS PATENT to James Chesterman, of Sheffield, in the County of:
York, Mechanist, for the Invention of "AN IMPROVED SPRING, ESPECIALLY.
APPLICABLE TO THE JOINTS OF KNIVES, RAZORS, SCISSORS, AND OTHER LIKE
ARTICLES."
Sealed the 27th May 1856, and dated the 22nd December 1855.
PROVISIONAL SPECIFICATION left by the said James Chesterman at'
the Office of the Commissioners of Patents, with his Petition, on the
22nd December 1855.
I, JAMES CHESTERMAN, of Sheffield, in the County of York, Mechanist, do
hereby declare the nature of the said Invention for "AN IMPROVED SPRING,
ESPECIALLY APPLICABLE TO THE JOINTS OF KNIVES, RAZORS, SCISSORS, AND OTHER
LIKE ARTICLES," to be as follows:-
My improved spring consists of a disc or dises, plate or plates, of steel or
other suitable metal, bent or otherwise made concave or conical: This concave
or conical disc rests upon its edge in a countersunk bed, or upon a plain,
surface, and being confined, as, for instance, by a rivet between two handles,
and the end of a blade of a knife, exerts a constant pressure sideways against.
the blade in endeavouring to regain its original shape or form. The edge may.
be hollowed out in parts, if desired, as the action of the spring depends upon.
its concave or conical form; and except for heavy pressure, it is not necessary
that it should have a bearing upon every part of its edge or base:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Chesterman in the. Great Seal Patent Office on the
21st June 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
CHESTERMAN, of Sheffield, in the County of York, Mechanist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of December, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of
Her reign, did, for Herself, . Her heirs and successors, give and grant unto
me, the said James Chesterman, Her special licence that I, the said James
Chesterman, my executors, administrators, and assigns, or such others as I,
the said James Chesterman, my executors, administrators, 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 Invention for "AN Im-
PROVED SPRING, ESPECIALLY APPLICABLE TO THE JOINTS OF KNIVES, RAZORS, SCISSORS,
AND OTHER LIKE ARTICLES," upon the condition (amongst others) that I, the said
James Chesterman, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, 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 calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said James Chesterman, 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 thereof, reference being had to the Drawings hereunto annexed.
(that is to say):-
My improved spring consists of a disc or discs, plate or plates, of steel or.
other suitable metal, bent or otherwise made concave or conical. This concave
or conical disc rests upon its edge in a countersunk bed, or upon a plane
surface, and being confined, as, for instance, by a rivet between two handles or.
"scales" and the end of a blade of a knife, exerts a constant pressure sideways.
against the blade in endeavouring to regain its original shape or form. The
edge may be hollowed out in parts, if desired, as the action of the spring
depends upon its concave or conical form; and except for heavy pressure, it is.

page_text: not.necessary that it should have a bearing upon every part of its edge or base:.
Under the term "concave "or "conical," I include all forms of curved. discs,
whether their sections be portions of circles, ellipses, or of any other forms.. :
Figure 1 of the Drawings hereunto annexed is a plan of such a disc as I
employ for my improved spring; Figure 2 is a transverse section of the same; :
Figure 3 is a plan of one in which the edge is hollowed out in parts, as before
mentioned; Figure 4 is a side view of a knife, shewn with the blade open,.to.
which my improved spring is applied; Figure 5 is a side view of the same
knife, with one part of the handle or "scale" removed, so as to shew the
interior of the knife; and Figure 6 is a longitudinal section of the same knife,.
taken at right angles to the plane in which the blade moves when opened and
closed.
The spring or disc a is shewn in section in Figure 6, and in dotted lines in.
Figure 5. In conjunction with my improved spring, I have introduced into.
the knife shewn in the Figures just mentioned a spring 6, with a projection c
upon its end for locking the blade when open. This spring has connected to it
a stud d, by which it is drawn back when the blade is to be closed, and pushed
forward so as to act as a wedge between the back of the shoulder of the blade
and the back of the knife when it is open, and thus lock it, as shewn in
Figure 5. A slot is formed in the back of the knife to allow the stud d to
slide to and fro.. A recess g is formed in the metallic portion of the handle,
against which the disc lies, so as to allow the disc to fall within it more or less
as it is compressed.
In Figures 7 and 8, I have shewn a knife handle, in which two springs or
discs, one on each side of the blade or blades, where two or more blades are
necessary, are employed; Figure 7 being a side view, and Figure 8 a longi-
tudinal section taken in the same direction as Figure 6. The springs or discs
in these Figures are marked a¹, and the recesses g¹.
In Figure 9, I have shewn a modification of the arrangement for locking
the blade. In this case the sliding piece marked b¹ is not a spring, but has
formed upon the end of it an abutment h, against which the end of a spiral
spring i acts. By means of this spring, the blade is locked as soon as it is
opened. In Figure 10, I have shewn another modification for effecting the
same purpose. In this case the end 6" of the piece 61 is bent, and forms a
spring taking against the metallic portion j of the handle.
In Figures 11 and 12, I have shewn a plan and a side view, partly in
section, of a pair of scissors, to which my improved spring is applied. The
screw is not shewn in Figure 12, and the disc appears in its uncompressed

page_text: form. A is the disc (shewn in dotted lines in Figure 11), and B is the recess.
The disc is placed beneath a washer D, on the outside of one of the blades, and
is compressed by the screw or rivet C, shewn in Figure 11.
In Figures 13 and 14, I have shewn a plan and a section of- a metallic
foot rule capable of being folded so as to be used either as a straight edge
or a square, suitable stops being provided. In this case the improved spring
or disc A¹ is placed between a washer B and the outside of one of the
legs or blades C', C¹, of the rule, a rivet or screw being passed through
the washer B', the spring A¹, and both of the legs or blades C¹, and clenched
by a rivet or screw until the spring is sufficiently compressed."
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim the improved
spring herein-before described, consisting of a concave or hollow conical disc
or plate compressed between two surfaces by a rivet, screw, and nut or other
equivalent, in the manner herein- before described, and represented in the
Drawings annexed, and the application thereof to the joints of metal rules;
pen and pocket knives, razors, scissors, and other like cutting articles.
In witness whereof, I, the said James Chesterman, have hereunto set my
hand and scal, this Twentieth day of June, One thousand eight hundred
and fifty-six.
JAMES CHESTERMAN. (1.S.)