IMPROVEMENTS IN RACK PULLEYS FOR WINDOW BLINDS
Year: 1875

page_text: LETTERS PATENT to Nathan Thompson, of the City of Brooklyn,
in the State of New York, in the United States of America, but at
present of 23, Southampton Buildings, in the County of Middlesex,
for the Invention of "IMPROVEMENTS IN RACK PULLEYS FOR WINDOW
BLINDS."
Sealed the 18th January 1876, and dated the 17th November 1875.
PROVISIONAL SPECIFICATION left by the said Nathan Thompson at
the Office of the Commissioners of Patents, with his Petition, on
the 17th November 1875.
I, NATHAN THOMPSON, of the City of Brooklyn, in the State of New
York, in the United States of America, but at present of 23, South-
ampton Buildings, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN RACK PULLEYS FOR
WINDOW BLINDS," to be as follows:-
The Invention has for its object improvements in rack pulleys for
window blinds, whereby great facility is afforded for adjustment of the

page_text: pulley in the rack whilst the pulley is at the same time firmly held in
any position to which it may be placed when in use.
For this purpose,
instead of fixing a spring pawl to the pulley slide to take into the rack
as heretofore, I form the slide to pass by preference over the face and
partly on each side of the rack, and I provide the slide with two pro-
jections at about right angles thereto, formed to take a bearing against
the inner surface of the face of the rack. On of these projections (the
upper one) is inclined on its face so as to enable it to take into the teeth
of the rack, and the lower one is formed so as to run clear of such teeth,
a suitable play being left between the parts. By these means, when it
is desired to tighten the blind cord, the pulley and slide are pushed
down the rack to the required. distance, when the strain of the blind
cord acting upon the pulley will cause the slide to cant or incline
slightly upon the rack, when the inclined tooth or projection will be
caused to engage with one or other of the teeth of the rack and thereby
hold the pulley firmly in position.
This arrangement of the parts also enables the pulley and slide to be
removed from the rack in an upward direction by simply canting the
slide outwards, thereby in many cases obviating the necessity for cutting
the cord for that purpose.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Nathan Thompson in the Great Seal Patent Office
on the 17th May 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NATHAN
THOMPSON, of the City of Brooklyn, in the State of New York, in the
United States of America, but at present of 23, Southampton Buildings,
in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of November in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Nathan Thompson, Her
special license that I, the said Nathan Thompson, my executors,
administrators, and assigns, or such others as I, the said Nathan

page_text: Thompson, 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 RACK PULLEYS FOR WINDOW BLINDS,” upon
the condition (amongst others) that I, the said Nathan Thompson,
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 Nathan Thompson, do hereby
declare the nature of the 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, that is to say :-
The Invention has for its objects improvements in rack pulleys for
window blinds, whereby great facility is afforded for adjustment of the
pulley in the rack, whilst the pulley is at the same time firmly held in
any position to which it may be placed when in use.
For this purpose,
instead of fixing a spring pawl to the pulley slide to take into the rack
as heretofore, I form the slide to pass by preference over the face and
partly on each side of the rack, and I provide the slide with projections
at about right angles thereto, and it is formed to take a bearing against
the inner surface of the face of the rack. One of these projections
(the upper one) is so formed as to enable it to take into the teeth of the
rack, and the lower one is formed so as to run clear of such teeth, a
suitable play being left between the parts.
And in order that my said Invention may be more clearly understood
and readily carried into effect, I will proceed, aided by the accom-
panying Drawings, more fully to describe the same.

page_text: according to my Invention; and Figure 5 is a front view; Figure 6, a
longitudinal section; Figure 7, an edge view; Figure 8, a cross section;
and Figures 9, detail views of a rack pulley, showing my Invention
applied thereto under a somewhat different modification.
In all the Figures similar letters of reference indicate like parts.
a is the rack, which in the case of Figures 1, 2, 3, and 4, is formed
in a similar manner to that ordinarily adopted, and the pulley slide bas
usual works within the cheeks of the same. Instead however of fixing
a spring pawl to the pulley slide b, to take into the rack teeth as
heretofore I form the slide b to pass by preference over the face and
partly on each side of the rack teeth, and I provide the slide with
projections b', 6%, at about right angles thereto, and the slide is formed
to take a bearing against the inner surface of the face a¹ of the rack.
The projection b¹ is capable of taking into the teeth of the rack, and the
projections 62 bear against the smooth surface of the rack at each side
of the rack teeth, so as to enable the lower end of the slide to run clear of
the rack teeth, a suitable play being left for the upper end of the slide
between the inner surface of the face a¹ of the rack and the teeth
thereof.
In the modification shown at Figures 5, 6, 7, 8, and 9, the rack is
formed with teeth at each side or edge thereof, and the slide is formed
with projections 68, 62, to clip around the exterior of the rack and yet
allow of the slide moving freely up and down thereon, the upper pro-
jections also permitting a suitable play at the upper end of the slide b
to enable the teeth or projections b¹ to take into the teeth of the rack
and to be removed therefrom as required. By these means, when it is
desired to tighten the blind cord, the pulley c and slide 6 are pushed
down the rack to the required distance, when the strain of the blind
cord acting upon the pulley will cause the slide to cant or incline
slightly upon the rack, when the tooth or projection 6' will be caused to
engage with one or other of the teeth of the rack and thereby hold the
pulley c firmly in position.
This arrangement of the parts also enables the pulley and slide to be
removed from the rack in an upward direction by simply canting the
upper end of the slide outwards away from the rack teeth, thereby in
many cases obviating the necessity for cutting the cord for that
purpose.

page_text: Having thus described the nature of my said Invention, and the
modes in which I carry the same into effect, I would have it understood
that what I claim is the mode of constructing rack pulleys substantially
as herein shown and described, whereby the use of a spring on the slide
is dispensed with, and the slide is enabled to be adjusted in the rack in
the manner herein described.
Having thus described the nature of my said Invention, and the
modes in which I carry the same into effect, I would have it understood
that what I claim is the mode of constructing rack pulleys substantially
as herein shown and described, whereby the use of a spring on the slide
is dispensed with, and the slide is enabled to be adjusted in the rack in
the manner herein described.
In witness whereof, I, the said Nathan Thompson, have hereunto
set my hand and seal, this Seventeenth day of May in the year
is dispensed with, and the slide is enabled to be adjusted in the rack in
the manner herein described.
In witness whereof, I, the said Nathan Thompson, have hereunto
set my hand and seal, this Seventeenth day of May in the year
of our Lord One thousand eight hundred and seventy-six.