An Improved Window Sash Balance.
Year: 1891

page_text: Date of Application, 20th Nov., 1891-Accepted, 9th Jan., 1892
COMPLETE SPECIFICATION.
An Improved Window Sash Balance.
1, ROBERT MCMILLEN of Pittsburgh, County of Allegheny State of Pennsyl-
vania, United States of America, Contractor, 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 :-
My invention relates to an improved sash balance; and it consists in a coil
spring attached to a toothed wheel adapted to mesh with a rack secured in the
window sash, a means for locking the said toothed wheel and thereby lock the
sash at any position, and also a device whereby the teeth of the wheel may be
disengaged from the rack to remove the sash from the fraine; together with
certain details of construction and combination of parts as will be fully described
hereinafter.
In the accompanying drawings,
Figure 1 is a side elevation of my improved sash-balance having the side plate
removed therefrom to show the interior working parts.
Fig. 2 is a sectional plan view of the same showing the sash balance in "position
in the frame of a window.
Fig. 3 is an outside elevation of the frame and a portion of the slotted lever for
the purpose of relieving the toothed-wheel from the rack.
To construct a sash balance in accordance with my invention I provide a frame 1
of a suitable size and form of construction, and arrange therein two levers 2,
pivoted at their tops 3 and arranged parallel to each other and provided at a
point near the centre with a rigid bar 4. These levers are capable of being moved
towards or away from the window sash 5 by means of a ratchet-bar 6, and an
eccentric toothed wheel 7, having a shaft and hand lever 8 connected thereto. To
accomplish this movement I form vertical slots, 9 through the lower ends of the
levers 2 and connect the same to the ratchet-bar 6 by means of pins 10, which
also project through shaped slots 11, formed through the frame 1. At the
forward end of the rack-bar 6 a short pins 12, which project through a
similar slot 13 to that formed at the rear of the frame 1 and serve as a guide for
the said rack-bar. Above this rack bar is pivoted a piece 14, having an upward
extension 15 to engage with the teeth of the wheel 7 and serve as a means for
locking the same. Attached to the rigid bar 4 is one end of a coil spring 16, the
other extremity of which is secured to a casing 17, secured to or formed integral
with the toothed wheel 7. Pivoted to the upper end of the frame 1 is a lever 18,
the lower end of which bears on the side of the wheel 7, and the pressure may be
regulated by a screw 19, passing through a beveled or wedge shaped block 21, to
move the said lever sidewise and thereby form a brake to retard or reduce the
force of the spring acting on the window sash. Placed beneath the surface on
each vertical edge of the sash are racks 20, which when engaged with the toothed
wheels completes the balance.
In operation two of these balances constructed as described are used to each
window sash and are placed in a mortise or opening formed at suitable points in the
window frame 22. The window sashes are fitted with the racks, as described, and
the wheels moved back by the hand-lever 8, so as to permit the sash to enter the
frame. By revolving the lever 8 to the right the eccentric permits the rack-bar 6
and the pivoted piece to move downward, thereby permitting the tension of the
spring to operate the toothed wheel to place an upward pressure on the racks
attached to the window-sash. This tension may be regulated by operating the
screw to increase or diminish the pressure of the brake bar on the casing
surrounding or attached to the spring. To remove the sash from the window

page_text: frames the hand-lever is revolved to the left until the rack-bar and eccentric
moves the toothed wheels out of mesh with the racks in the sash. To lock the
window sash at any desired point the pivoted piece 14 is engaged with the toothed
wheel by means of the hand-lever, as shown at Fig. 1 on the drawings.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
The herein described window-sash balance, consisting of the frame 1, the
levers 2, pivoted therein, and a means for moving the same toward or away from
the window sash, a suitable coil spring, mounted between the said levers, suitable
racks placed in the window-sash in mesh with the said wheel, and a device whereby
the wheel may be locked and thereby lock the window-sash, substantially as and
for the purpose set forth.
In testimony that I claim the foregoing I hereunto affix my signature and
scal this 7th day of November A.D. 1891
Witnesses:
M. E. HARRISON.
F. W. MERTINS.
ROBERT MCMILLEN.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.