Improvements in the Mechanism of Venetian Blinds.
Year: 1885

page_text: Improvements in the Mechanism of Venetian Blinds.
I JOSEPH SIMPSON, Residing at Brook Road, Heaton Chapel, near Stockport,
& in the County of Lancaster, Engineer do hereby declare the nature of my
invention for IMPROVEMENTS IN. THE MECHANISM OF VENETIAN BLINDS, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In this arrangement of mechanism for Venetian Blinds I use the principle of an
extension of the path of the cords between the hand of the operator & that portion
of the cords which pass down through the laths of the blind. This extension of the
path of the cords I obtain by introducing an additional pulley (or pulleys) in the
top rail at the reverse end, (to the usual pulleys) I traverse the two cords together,
first over one of the original pulleys, then over the top rail, round the new pulley
at the other end, then I pass the two cords under the top rail & round the second
of the original pulleys to the top side of the rail. At this point (when the blind is
down, as shewn in Fig. 1) the two cords are fastened together (two or three inches)
either by sewing or splicing, & from this point of junction of the two cords they
separate, one passing over each of the two original central pulleys. They are then
threaded through the laths of the Blind to the bottom rail. At this point (where
the cords usually terminate with a knott) I introduce a pulley to each cord, &
passing the latter round the said pulleys, repass them through the laths (of the
blind) to the top rail, passing the cord ends through a small hole secure it there
with a knott.
The object of this extension of the path of the cord is to provide a sufficient
space (beyond the reach of the operator) for the junction of the two cords to traverse
the required distance round about the top rail for the requirements of the blind
being raised & lowered, & as the junction of the two cords compels them to travel
evenly, the level of the blind is secured for all positions of height.
The object of the additional pulleys at the lower rail is to introduce (the well
known) mechanical leverage of the moveable pulley or pulleys, (as in the case of
very long or heavy blinds). The number of pulleys may be increased, as the intro-
duction of a single pulley to each cord reduces (the effective) weight of the blind
one half, & the increased number in proportion. The other half of the weight
being sustained by the stationary cord resting upon the knott above the top rail.
It will be obvious that when the operator proceeds to raise the blind by pulling the
vertical cords (as usual) the whole of the cords passing round about the pulleys in
the top rail, the junction of the cords also continues in some part of that path &
therefore the level of the blind cannot be disturbed, and as the moveable pulleys
perform the duty of releiving the weight, the operation of raising the blind is
greatly facilitated.
I will now proceed to describe the drawings.
Fig. 1. represents a front elevation of a Venetian Blind, with the improvements
applied.

page_text: Fig. 3. is a plan of the bottom rail, & Fig. 4. is a section through M. D. I will
now fully describe the Figs. 1. 2. 3. & 4. and their mode of action.
The same letters of reference apply to the said Figs.
In Fig. 1. the only new part at the top is the pulley A. The object of this pulley
is to extend the path of the cord, so as to allow of a sufficient length for the two
distinct cords being worked.
•
The said cords (when the blind is down as shewn in Fig. 1.) are joined together
(either by sewing or splicing) for a distance of two or three inches at the point
marked C. The cords being continued as at B1, B2 round the pulleys L. A. & K, &
finally to the hand of the operator at B, either by a continuation of the two cords,
or by a single cord.
The cords having passed round the pulleys L. A. & K (as above described) are
now separated from the junction at C. & led forward, one cord to the pulley M. &
the other to pulley N, & from thence the cords are threaded down through the laths
to the bottom rail as at 1-1. They then are passed under the moveable pulleys
D. D, & are led back as at J. in Fig. 4, through the blind & secured by a knott at the
top as shewn at E. E.
To raise the blind, the operator takes hold of the cord at B. Fig. 1. pulling
down as usual. The cords traverse round the pulleys K. A. L. as shewn in
Fig. 2. whence they pass by the pulleys M. & N. down through the blind (as above
described) return under the moveable pulleys D. D. & up to the termination by the
knott at the top, & by this operation the blind is raised evenly, & with half the
usual power.
The moveable pulleys may be inserted in an intermediate rail (or bar) as in
Fig. 5. In this case the end of the cord (after passing under the moveable pulleys
D. D. is led over the additional pulleys L. L. at the top) is again led down through
the blind to the bottom & is secured there by a knott at M. M. Fig. 5.
Fig. 6 is a plan of the top rail shewing the pulleys L. L.
Fig. 7 is a plan of the
bottom rail.
Fig. 8. is a section through the line, of cords & pulleys shewing the pulleys
L & D-The path of the cords I. J & K and the knott M at the bottom. The
effect of this position of the moveable pulleys D. D. is to raise the upper half (or
portion) of the blind to the top first, taking the accumulation of the laths away
from the centre of the window, leaving the lower portion of the blind hanging in
open order for the free admission of light. By continuing the operation of pulling
at the cords they will traverse round all the pulleys & draw up the remaining
portion of the blind to the top.
Fig. 9 is a front elevation of another modification, Fig. 10 is a section of the
same, & fig. 11. a plan view of the lath. In this arrangement the cords pass over
the pulleys M & N. Figs. 9 & 10, & down through the openings in the edges of
the laths as at 1 & J, Fig. 10, pass under the moveable pulleys D. D & return to the
top rail & are there secured by a knott at the top, E. E, Fig. 9. This arrangement
adinits of the laths being removed for cleaning &c without unthreading the cords.
The gain by the moveable pulleys is the same in this form as in Figs 1 &c.
Fig. 12 is a Venetian (in front elevation) Blind, having the cords & pulleys
threaded in the ordinary way. In this arrangement the moveable pulley is applied
externally to the blind at D, & is connected with the bottom rail through the
medium of the original cords. The draw cord (being single) is secured by one end
to a fixd pin (or loop) at O. The other end is passed round the pulley D, &
reaches the hand of the operator at B. This view illustrates the moveable pulley,
as applied to the usual draw cords, & by its introduction the single cord & pulley Ď,
gives the same leverage of 2 to 1. or releives the (effective) weight by one half, as
well as preserving the level of the blind in all positions.

page_text: Having now particularly described and ascertained the nature of my Inven-
tion and in what manner the same is to be performed, I declare that what
I claim is
1st The introduction of the pulley A for extending the path of the cords &
thereby preserving the level of the blind.
2nd The application of the moveable pulleys for reducing the (effective) weight
of the blind, & facilitating the operation of raising & lowering the same.