IMPROVEMENTS IN VENETIAN BLINDS
Year: 1879

page_text: LETTERS PATENT to George Whitaker, of 38, Sutherland Place, Bayswater, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN VENETIAN
BLINDS"
PROVISIONAL SPECIFICATION left by the said George Whitaker at the
Office of the Commissioners of Patents on the 28th June 1879.
GEORGE WHITAKER, of 38, Sutherland Place, Bayswater, in the County of Mid-
dlesex. "IMPROVEMENTS IN VENETIAN BLINDS."
This Invention has for its object improvements in Venetian blinds.
Instead of using slips of wood, or iron, or cardboard, which have been hitherto
the chief if not exclusive materials employed for the purpose, I make my slips of
the peculiar material known by the various names of cupro-ammonium paper,
cupro-lignine, cuproxyleno, and still other designations, the material being an
aggregation of ligueous matter, whether in the form of paper or woven ligueous
tissue, or both combined, and which is now manufactured commercially. The slips
are fluted or corrugated in the direction of their length, which admits of their boiug
made lighter than they otherwise could be to retain their form when in use. They
may retain the natural surface and colour of the specific material used, or may be
painted, varnished, or otherwiso ornamented.
Venetian blinds made according to my process are thinner, lighter, cheaper, and
more durable than others.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Whitaker in the Great Seal Patent Office on the 24th
December 1879.
GEORGE WHITAKER, of 38, Sutherland Place, Bayswater, in the County of Mid-
dlesex. "IMPROVEMENTS IN VENETIAN BLINDS."
This Invention has for its object improvements in Venetian blinds.
Instead of using slips of wood, or iron, or cardboard, which have been hitherto
the chief if not exclusive materials employed for the purpose, I make my slips of
the peculiar material known by the various names of cupro-ammonium paper,
cupro-lignine, cuproxylene, and still other designations, the material being an
aggregation of ligneous matter, whether in the form of paper or woven ligneous
tissue, or both combined, and which is now manufactured commercially. The slips
are or may be fluted or corrugated in the direction of their length, which admits of
their being made lighter than they otherwise could be to retain their form when in
use. They may retain the natural surface and colour of the specific material used,
or may be painted, varnished, or otherwise ornamented.
Venetian blinds made according to my process are thinner, lighter, cheaper, and
more durable than others.
Having thus stated the nature of my Invention, viz., the use of the material
known as cupro-ammonium paper or tissue, otherwise known as "cuprolignine,"
'cuproxylene," and by still other designations, I will now specify particulars of
the method I follow for converting the aforesaid material into Venetian blinds.
"1
I will preface my description by defining a Vonetian blind, according to my
menning, to be a blind made up of laths or splints either pendent or vertical, and I
will now describe the manufacture of a pendent Venetian blind according to my
process.
Looking at an ordinary pendent Venetian blind as it bangs in place, and
examining it from above downwards, the first part to come under notice will be
the pulley block, as I call it, being a bar of wood much thicker than the laths or
splints which constitute the actual blind. Next come the laths or splints, n
thick one first, then thinner ones, until the last or lowermost one of the lot,
which is thicker than the intermediate laths or splints, hut not so thick as the
first.
Now although I can make not only the pulley block but also the first and last
(or thick splints) out of cupro-ammonium material, as specified, yet I do make the
above mentioned parts out of wood, exactly as at present, the cupro-ammonium
material being wholly applied to making the thin laths or splints.
These laths or splints are either plain or corrugated. I will first describe tho
manufacture of a plain lath. For this purpose I either take ordinary commercial
cupro-ammonium card of suitable thickness, and cut it into slips of length and
breadth necessary for the blind I design to make, or else I manufacture my own
card by sticking sheets of paper or paper alternating with ligneous woven tissue
(linen, calico, &c.) together with the fluid now well known as "cupro-ammonium.”
Supposing me to have begun on ordinary commercial cupro-ammonium card of
suitable thickness, and to have cut it into the necessary dimensions, I next trim
the edges to get rid of any burr or raggedness which the cutting may have
occasioned. To this end I luck a thickness of horizontally stacked laths together,
then subject the edges to the action of a bookbinder's guillotine. This gives a clean
edge, and is the method I adopt and recommend, but sand or emery paper hand-
used give an equally good result. The operation however is much slower, and has
only the recommendation of saving first cost of the guillotine.
The laths having heen cut into shape and trimmed, have next to be perforated
for passage of the suspension cords. Here again the question as to hand labour or

page_text: machine labour arises. Each lath may be perforated singly, in which case a common
punch is the best instrument to employ; but perforation by hand labour, lath by
lath, is not the method I adopt and recommend. I proceed as follows:-Having
locked up a convenient number of cupro-ammonium laths I drill a round hole
through the lot, using a tool not differing as to its cutting part from a joiner's
ordinary cutting centre bit. The tool however cannot be profitably used in con-
nection with a bow, but must be framed or supported in such manner that the
circular cutting edge shall begin its cutting at right angles to the plane of stacked
laths, and so continue until the entire perforation has been accomplished.
The perforations when complete are not to be round, but more or less ovoid.
The round hole can be worked into required shape either by hand filing or gouging,
and this through an entire block of stacked and compressed laths; but what I
prefer is a punch edged cutting tool forced through the compound block of laths by
hydraulic or other adequate pressure.
So far as plane or flat lnths are concerned the operation of making them is
finished, and they can at once be built up into a Venetian blind in the ordinary
manner. I will now describe how a fluted or corrugated lath is made, beginning
with the ordinary commercial cupro-ammonium card. For the purpose of making
a fluted or corrugated lath out of cupro-ammonium material, a card of half the
thickness necessary for a plain lath will suffice, so that whereas what is com-
mercially known as "four ply" card is necesary for a plain lath, “two ply" card is
thick enough for a lath that is fluted; or, stated in parts, the plain lath should be
about one sixteenth part of an inch in thickness, and for the corrugated lath one
thirty second part of an inch will suffice. The fluting or corrugation may be
accomplished by different methods. Plane pressure between two corrugated iron
or steel blocks answers very well, so does roll pressure between a pair of corrugated
cylinders, and whether the corrugations upon the cylinders be at right angles to
the axes of the cylinders, or longitudinal and parallel to the same axes, a good
result will follow if my directions be followed. Whether the one or the other, it is
absolutely necessary that the cupro-ammonium lath be subjected to the corrugating.
process in the softened not the dry condition, and that the corrugating machinery
be made of iron or steel. Softening is accomplished by immersing the dry lath for
about five minutes in a bath of weak cupro-ammonium liquid, made by adding
about three parts by volume of water to one part of the strong cupro-ammonium
liquid, formed by steeping metallic copper in liquid ammonia of 880 specific gravity,
and allowing the copper to steep until the ammonia is saturated. If a plano lath
taken from such a bath be subjected to corrugating pressure, and then dried on a
surface with like corrugations, it will retain when dry the corrugations. About
eight corrugations in the width of the lath will be found suitable; they should
be easy undulations, of a depth for each corrugation equal to about one sixth of
an inch.
I will now state how a blind lath of my material is made when ordinary paper
is used to begin with, and not ready formed commercial cupro-ammonium card.
For this purpose it is only required to spread the strongest cupro-ammonium liquid,
made with 880 ammonia, over successive layers of paper, just as mucilage or paste
would be spread, and then stick the layers of paper one upon the other until the
necessary thickness is achieved. A vegetable fibro brush, I must remark, not a
hair brush, must be used for this purpose. If corrugation bo desired no softening
will in this case be needed, the lath being soft already. I prefer to use commercial
cupro-ammonium card for my process of blind manufacture, but at present the pro-
duction of it on the large scale and by special machinery is a monopoly, and the
cupre-ammonium card being much required for other purposes than mine, 1 contem-
plate the possibility of not being able to supply myself in every case with it at the
time being with certainty or regularity.
The perforations in corrugated laths may either be effected before corrugation or
after; I prefer to make them previous to corrugation.

page_text: The advantages of laths made by my process over ordinary laths are the fol-
lowing: They are almost noiseless; they do not readily ignite, and if ignited do
not blaze; they are thinner than laths of either wood or iron, and much cheaper ;
being waterproof, can be used without painting or varnishing for outside as well as
inside work. The natural color of the cupro-ammonium paper or tissue is a delicate
green; if desired to be red, streaking the paper over with a solution of prussiate
of potash will accomplish this change. If desired of any other color the surface
must be painted, though paint and varnish in no way add to the waterproof
quality.
Finally, to summarise the particulars of my claim, it is the manufacture of
Venetian blinds out of a material (cupro-lignine paper or tissue, cuproxylene, &c.)
which prior to my discovery of its suitable applicability had never been used for
that purpose, and although I have specified the method of generating cupro-
ammonium fluid, and the way in which it can be used for the manufacture of
Venetian blinds in cases where cupro-ammonium card or tissue is not commercially
attainable, yet these specifications constitute no part of my Patent claim, which is
the application, substantially as described, of cupro-ammonium paper, tissue, or
fabric to the manufacture of Venetian blinds; and I must farther state that although
I have given definite strengths of solution, and mentioned specific tools, yet such
statements are to be regarded as only for an operator's guidance.
In witness whereof, I, the said George Whitaker, have hereunto set my hand
and seal, this Twenty third day of December, in the year of our Lord Ono
thousand oight hundred and seventy nine.