An Improvement in Self Acting Window Blind Apparatus.
Year: 1887

page_text: An Improvement in Self Acting Window Blind Apparatus.
We, WILLIAM HOLMES NISBET, Mavisbank Partick, Lanarkshire, Engineer, and
WILLIAM WRIGHT VIRTUE of 505 Springburn Road, Glasgow, aforesaid, Engineer,
do hereby declare the nature of this invention to be as follows:-
Our invention relates to self-acting window blind apparatus of the kind described
in the Specification of Letters Patent granted to us Number 12,653 and dated
22nd October 1885 and it consists of an improvement in the brake or friction pad
which holds the barrel with the blind in its balanced position the object of the invention
being to obviate unequal wear of the ratchet sleeve and stud of the apparatus caused
by the pressure of the pad carrying spring upon one side of the axis. "To that end we
secure upon the ratchet sleeve of the apparatus two friction pads carried by volute or
like springs or blades upon opposite sides of the axis the spring blades are or may be
fitted together at their ends to form an elliptical eye which is passed over and embraces
the ratchet sleeve, the sleeve being made in section of the elliptical form of the eye in
order to retain the spring brake from turning upon it.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow,
Agents.

page_text: COMPLETE SPECIFICATION.
An Improvement in Self Acting Window Blind Apparatus.
We, WILLIAM HOLMES NISBET, Mavisbank, Partick, Lanarkshire, Engineer, and
WILLIAM WRIGHT VIRTUE of 505 Springburn Road, Glasgow, Engineer, 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:-
11
To
Our Invention relates to self acting window blind apparatus of the kind described
in. the Specification of Letters Patent granted to us Number 12653 and dated
22nd October 1885 and it consists of an improvement in the brake or friction pad
which holds the barrel with the blinds in its balanced position the object of the
invention being to obviate unequal wear of the ratchet sleeve and stud of the apparatus
caused by the pressure of the pad-carrying spring upon one side of the axis.
that end we secure upon the ratchet sleeve of the apparatus two friction pads carried
by volute or like springs or blades upon opposite sides of the axis. The spring
blades are or may be fitted together at their ends to form an elliptical eye which is
passed over and embraces the ratchet sleeve, the sleeve being made in section of the
elliptical form of the eye in order to retain the spring brake from turning upon it.
In the accompanying drawings which illustrate our invention figure 1 is a sectional
elevation and figure 2 a cross section at the line 1---1 in figure of the barrel and
operating mechanism of a self acting window blind. A, is the ratchet sleeve on
which are secured the two spring blades B, B, carrying at their free ends the friction
pads C, C, which by bearing against the internal surface of the barrel end or cover D
prevent the barrel being turned by the weight of the blind. The inner ends of the
springs form an elliptical eye which embraces the ratchet sleeve A, and the end of
each spring engages the other spring or may be otherwise secured on the sleeve. In
other respects the operating mechanism of the blind is similar to that described in
the Specification of our earlier patent herein before referred to.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In self acting window blind apparatus a duplex or double spring friction brake
constructed and arranged to operate substantially as hereinbefore described.
Dated this Fourteenth dex of 1000