Improvements in Deckle Straps for Paper Making Machines.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Deckle Straps for Paper Making Machines.
I, JOHN COCKBURN, Superintendent to the North British Rubber Company
(Limited) Castle Mills, Edinburgh, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
In deckle straps for paper making machinery as ordinarily made a ply or plies of
cloth is or are embedded prior to vulcanization within the rubber of which the
deckle strap is composed for the purpose of limiting its elasticity or preventing its
elongation under tension. In practice it is found that the supporting fabric becomes
warped or waved during the process of vulcanization of the strap with the result
that the finished deckle strap is often rendered inefficient or useless in respect that
it gets warped or waved (and it cannot be prevented from becoming so by the mode
of construction heretofore followed). To amend this defect in use tension is often
put on the straps to overcome the waving and make them lie closely on the wire
cloth apron of the paper machine, such tension not only doing injury to the straps
but operating against their effective working.
To obviate such a result and ensure the production of deckle straps that shall be
perfectly reliable in operation, I make a deckle strap in two or more sections longi-
tudinally that is I take two strips or lengths of rubber or rubber compound such as
represented in the accompanying diagrams in cross section at A A' Figures 1
and 2 and on the face of each of which I cement or otherwise secure a strip or
length of rubber frictioned cloth or other suitable fabric a a' a little less in width
than the rubber strap. The rubber and cloth strips being pressed together I
partially vulcanize the same in a suitable mould. I subsequently cement or
otherwise fix together the two sections so prepared separately with the fabrics face
to face as indicated at Figure 3 and then vulcanize the whole or complete the
process of vulcanization thereof in the same or another suitable mould. Instead
of placing a length of fabric in each section, I may secure the fabric a on one
section A. only as indicated at Figure 4 and cement and vulcanize thereon a section
or layer A of rubber only (shown at Figure 5) so as to embed the fabric between
the layers of rubber when they are put together as indicated at Figure 6.
I may
sometimes mould a groove in one or both of the rubber sections to form a recess
in which to place the layer or layers of prepared canvas or other fabric to be
covered up between the two sections when the final vulcanization is being
performed.
By making deckle straps in the manner described, the operation of placing or
embedding the fabric on or in the rubber can be carefully observed and risk of the
fabric becoming warped or waved is entirely obviated; and deckle straps can be
produced that will rest evenly on the wire cloth apron of the paper machine by their
own weight and without undue tension.
I prefer to make the under and upper surface of the strap slightly hollowed out
between the edges of the surface so that the weight of the strap may rest on the two
edges of the under surface for the time being and thereby conduce to make the
edges of the paper more even.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
A deckle strap constructed from two or more layers or longitudinal sections of
rubber independently prepared and partially vulcanized one or both of which
sections have a ply or plies of cloth on the surface or surfaces the sections being

page_text: subsequently laid together and subjected to final, vulcanization substantially
described.
Dated this Sixth day of September 1892.
as
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.