IMPROVEMENTS IN DECKLE STRAPS USED BY PAPER MAKERS
Year: 1873

page_text: LETTERS PATENT to Isaac Blue Harris, of Castle, Mills, Fountain--
bridge, Edinburgh, for the Invention of "IMPROVEMENTS IN DECKLE
STRAPS USED BY PAPER MAKERS."
Sealed the 24th June 1873, and dated the 28th April 1873..
PROVISIONAL SPECIFICATION left by the said Isaac Blue Harris
.
at the Office of the Commissioners of Patents, with his Petition,
on the 28th April 1873.
.. J
I, ISAAC BLUE HARRIS, of Castle Mills, Fountainbridge, Edinburgh,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
DECKLE STRAPS USED BY PAPER MAKERS," to be as follows:-
1
Deckle straps when made of india-rubber have hitherto been formed.
with two or more layers of canvas placed centrally in the straps, and
these straps are generally made from three-quarters of an inch to one
and a half inches in thickness. This thickness being considerable, such
a position of the canvas has been the cause of rapid deterioration of the
straps from cracks in the outside edges. To obviate this defect I change,
1
U

page_text: the position of the cloth base or canvas layers, embedding the same at
one side instead of in the middle of the fabric. This change of position
of the canvas entirely removes the above named defect, and a much
more flexible, perfect, and durable strap is obtained. It also permits of
another important improvement, viz., an economy of materials, for in
the side opposite to that in which the canvas layers are inserted may
be formed a longitudinal groove throughout the entire length of the
strap. This arrangement is much better than the groove on each side
heretofore employed in straps made with the canvas central, for such
straps retain the defect due to the central position of the canvas, and
when grooved form a very ineffective surface for the action of the
driving pulleys.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Isaac Blue Harris in the Great Seal Patent
Office on the 28th October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAAC
BLUE HARRIS, of Castle Mills, Fountainbridge, Edinburgh, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of April, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Isaac Blue Harris, Her special
licence that I, the said Isaac Blue Harris, my executors, admini-
strators, and assigns, or such others as I, the said Isaac Blue Harris,
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
"IMPROVEMENTS IN DECKLE STRAPS USED BY PAPER MAKERS," upon the
condition (amongst others) that I, the said Isaac Blue Harris, my
executors or administrators, by an instrument in writing under my,
or their or one 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

page_text: BELOVED BECAU
mimediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Isaac Blue Harris, 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, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon, (that
is to say)
:-
i
India-rubber deckle straps as hitherto made have been strengthened
by the insertion into the rubber of two or more layers of canvas placed
centrally in the straps. These straps generally measure from three
quarters of an inch to one and a half inches in thickness, and when at
work they are caused to travel at tension under and over small driving
and guide rollers. The central position of the strengthening and inelastic
canvas has been the cause of a rapid deterioration of the straps from
cracks in their outside edges, for the reason that the length of surface in
contact with each of the end guiding pullies at any given time is less by
about three inches than the outside surface of the corresponding part of
the strap, and that the required extension to allow for this inequality.
takes place through only one half the thickness of the strap. To obviate
this defect I change the position of the cloth base or canvas layers'
embedding the same at one side instead of in the middle of the fabric.
This change of position of the canvas entirely removes the above named
defect, and a much more flexible, perfect, and durable strap is obtained.
'
In the accompanying Drawing my improved deckle strap is shewn in
contrast with the ordinary manufacture of india-rubber deckle strap;
Fig. 1 being a cross section of the deckle strap as hitherto manufactured
and Fig. 2 a similar view of my improved deckle strap. In both of
these views a represents a rectangular strip of india-rubber, and 6 the
canvas layers inserted for strengthening the strap. It will be seen that
the difference between these two straps consists only in the change in
position of the canvas layers. The importance of this change will be
better appreciated by reference to Fig. 3, where A represents a deckle
strap pulley of a paper making machine; B, the deckle strap passing
over and under the pulley A, and pressing upon the wire cloth C to form.
a wall at the edge thereof for preventing the escape of the pulp as it is
discharged on to the web.

page_text: As the body of the strap is necessarily subjected to unequal tension
while passing round the pulley, it is manifest that the greater the
diffusion of this action the less will the strap be injured. The bringing
therefore of the inelastic layers nearer to the surface which comes in
contact with the pulley ensures a greater diffusion of the strain through 5
the overlying thickness of rubber, and thus the tendency of the strap to
crack at the outside edges is greatly reduced.
Fig. 2 shews a portion of the strap in side elevation.
Figures 4 and 4º, shew in cross section and side view another form of
my improved strap in which an economy of materials is effected, for in 10
the side opposite to that in which the canvas layers are inserted a longi-
tudinal groove is formed throughout the entire length of the strap.
This arrangement is much better than the groove on each side hereto-
fore employed in straps made with a central canvas layer, as shewn in
Fig. 5; for such straps retain the defect due to the central position of the 1
canvas, and by being grooved on their inner face they form a very
ineffective surface for the action of the driving pulleys.
Having now set forth the nature of my Invention of "Improvements
in Deckle Straps used by Paper Makers," and explained the manner of
carrying the same into effect, I wish it to be understood that under the 20
above in part recited Letters Patent, I claim, manufacturing deckle
straps in the manner described with reference to Figures 2 and 4 of the
Drawings.
Drawings.
In witness whereof, I, the said Isaac Blue Harris, have hereunto
set my hand and seal, the Twenty-second day of October, in the 25
year of our Lord One thousand eight hundred and seventy-
three.