Improvements in Sash-balances.
Year: 1890

page_text: QUALI LEIM DIMITTALION
Improvements in Sash-balances.
A communication from abroad by THE MARSHALL IMPROVED WINDOW-FURNITURE
COMPANY, of San Francisco, California, United States of America.
I WILLIAM EDWARD GEDGE of No. 11 Wellington Street, Strand, London in the
County of London, Patent Agent, 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 :—
This invention relates to the general class of sash-balances in which springs are
employed, and particularly to that class exemplified by Letters Patent No. 1458
of 1890, granted to Benjamin Marshall, of San Francisco, California, Physician. It
consists in the novel torsional spring, hereinafter described, and in its application and
use in a sash-balance mechanism.
The advantages of this spring are that it provides for the maximum strength or
tension, with the minimum length of spring; and also that it exerts a more equal
power.
Referring to the accompanying drawings
The Figure is a section of a corner of a window-sash showing the spring in elevation,
its coils being here shown as distended more than they would be in practice in order
to show their outward and return course.
The spring A is made of any suitable material, of any proper shape in cross-section,
and of suitable dimensions.
Its course is spirally outward from one end to the other, but, instead of stopping at
the outer end, it turns back upon or within itself, being still directed spirally, and
returns to the first end, where it may stop or be carried back again, if desired.
Thus there are formed wide pendent layers, the one within the other.
In practice, this spring is placed in a bore made in the sash-rail B..
To the edge of the sash is secured a plate C, with which at c, one end of the spring
is connected. In this plate is journaled a short turn-rod D, and to the inner end of
this rod the other end of the spring is attached.
The rod carries a pinion E, which meshes with a rack F fixed to the window-casing.
In operation, as the sash is moved to a closed position, the spring is wound up and
so serves as a balance or an assistance in raising the sash.
The spring need not be very long; a short one is more convenient and can be better
applied to the sash.
If an ordinary spiral spring were used, it would have to be a very long one in order
to get the necessary power, and a very deep bore would have to be made in the sash
to receive it.
It would also have a tendency to bend and kink. But such a spring as herein
described can be short and yet have the necessary power, and it remains perfectly
straight under any required tension.
Another great advantage of this spring is that its power is better distributed and
equalized, and it affects the sash about equally in all positions.
Having now particularly described and ascertained the nature of the said
invention, (communicated to me as aforesaid) and in what manner the same is to be
performed, I declare that what I claim is :-
1. In a sash-balance or analogous device, the torsional spring herein described,
consisting of a single coiled piece returned within itself, having one of its ends fixed to a
non-rotary bearing, and the other secured to a piece that has a rotary movement.

page_text: 2. In a sash-balance or analogous device, an axially-moving rod and a rack and
pinion for operating the same, in combination with a torsional spring returned within-
itself, having one of its ends secured to the axially-moving rod, and the other fixed to
a non-rotary piece, substantially as described.