Resilient friction sash balance

A unitary weatherstripping and self-balancing sash guide for slidingly embracing the juxtaposed side edges of a pair of double-hung inner and outer window sash units, and guiding their sliding opening and closing movement in a window opening, comprises an arched portion spanning the side edge of the window opening and having a central parting bead protruding into the window opening, inner and outer terminal flanges protruding from the arched portion into the window opening, and two slanting wing flanges respectively extending cantilever-fashion from the parting bead diagonally toward the arched portion and the respective terminal flanges, forming therewith a pair of channel-shaped grooves each embracing the side edge of one sash unit, whereby each of the two sash units is slidingly gripped in resilient tractive balancing engagement between a terminal flange and a facing slanting wing flange resiliently deformed by the embraced sash unit.

TECHNICAL FIELD 
This invention relates to window sash guides for double-hung windows and 
particularly to a unitary resilient self-balancing sash guide capable of 
maintaining the window sash in any desired raised position from the top to 
the bottom of the window frame without requiring counterweight sash 
balances, tension spring sash balances, torsion spring sash balances or 
other costly separate attachments to maintain the sash in its raised 
position. These unitary resilient deflectable self-balancing sash guides 
are preferably formed as extrusions of plastic material having a central 
substantially rectangular hollow parting bead provided with diagonally 
protruding wing flanges extending from an inner portion of the parting 
bead toward the outer side edge of the window sash and bearing against the 
face of the window sash in sliding engagement, with the sash resiliently 
deflecting and deforming its wing flange, producing tractive friction 
force applied against the face of each sash tending to maintain it in any 
raised or lowered position. 
BACKGROUND ART 
Various United States patents have proposed sash guides incorporating 
diagonal flexible flanges employed to produce resilient force bearing 
against window sashes when deflected by installation of the sash. Sylvan 
U.S. Pat. No. 2,244,739 shows rolled sheet metal sash guides provided with 
a long diagonal tongue 16 extending from the outside corner of the sash 
guide inwardly toward the edge surface of the window sash. Sylvan's tongue 
is employed for balancing the sash and also for providing a 
weatherstripping action. In addition, the inner and outer terminal flanges 
of Sylvan's rolled metal section sash guide are resilient and thus hold 
the sash guide in place in the jamb in which the weatherstrip is located, 
but the resilience of these inner and outer flanges of Sylvan's sash guide 
does not apply any resilient force against the sash. 
Resilient "Z" cross-section or "U" cross-section rolled sheet metal sash 
guide supports are shown in Gardner, Jr., U.S. Pat. No. 2,613,403, and 
resilient "Z" cross-section leaf spring weatherstripping material is shown 
in Dennis, U.S. Pat. No. 1,666,327; Blessin, U.S. Pat. No. 1,976,767; and 
Beil, U.S. Pat. No. 2,541,325. Resilient leaf spring sash guides employed 
for weatherstripping are shown in Robinson, U.S. Pat. No. 2,192,776; 
Mears, Jr., U.S. Pat. No. 3,269,062 and Hettinger, U.S. Pat. No. 
2,775,795. All these patents apply resilient force along the edge surfaces 
of the sliding sash unit, rather than against the face of the sash. For 
this reason the prior art resilient weatherstripping sash balances permit 
lateral rocking play of the sash sidewise between two opposing resilient 
leaf spring flanges, and precise alignment and positioning of the sash is 
not possible with these prior art proposals. 
With the present invention, direct diagonal resilient flanges apply 
pressure against a face of each sash along its vertical edge, urging the 
sash outwardly toward the outer fixed flange of the unitary sash guide and 
thus assuring its precise positioning without rocking or lateral play, 
while still achieving the advantages of resilient balancing and 
weatherstripping. 
DISCLOSURE OF THE INVENTION 
The unitary sash guides of the present invention offer these 
weatherstripping and resilient leaf spring balancing features combined 
with significant manufacturing economy, since the preferred embodiments of 
the invention are formed as unitary plastic extruded sections. A gently 
arched configuration accommodates the slightly tapered side edge surfaces 
of the sash. This arched cross-section joins the inner terminal flange to 
the outer terminal flange of the sash guide, and the center portion of the 
arch supports a rigidifying box beam or channel-shaped parting bead 
section, which forms a hollow rectangular central part of the extrusion. 
Extending from the innermost corners of this parting bead section of the 
extrusion are diagonally extending wing flanges slanting outward toward 
the arched wall of the sash guide, producing a resilient depressible 
balancing flange which also provides weatherstripping action. Insertion of 
the sash between the wing flange and the opposing terminal flange 
depresses the wing flange thereby urging the sash against the outer 
terminal flange and providing sash balancing tractive force between the 
sash and its sash guide. 
Accordingly, a principal object of the present invention is to provide a 
lightweight, easily fabricated and highly economical window sash guide for 
double-hung sliding sash windows incorporating a central parting bead 
having diagonally extending wing flanges resiliently deflectable by 
installation of sliding window sash to apply tractive sash balancing and 
weatherstripping force directly against the face of the sash. 
Another object of the invention is to provide unitary extruded sash 
balances of this character providing resilient tractive sash balancing 
without requiring any additional component parts whatever. 
Other objects of the invention will in part be obvious and will in part 
appear hereinafter. 
The invention accordingly comprises the features of construction, 
combinations of elements, and arrangement of parts which will be 
exemplified in the construction hereinafter set forth, and the scope of 
the invention will be indicated in the claims. 
For a fuller understanding of the nature and objects of the invention, 
reference should be had to the following detailed description taken in 
connection with the accompanying drawings in which:

BEST MODE FOR CARRYING OUT THE INVENTION 
As shown in FIGS. 1, 2 and 4, the unitary sash guides of the present 
invention are typified by a plastic extrusion having an arched 
cross-section. The sash guide 10 of the present invention thus comprises 
an arched central portion 11 comprising a pair of oppositely slanting 
raked sash-facing panels 12, unitarily joined by a substantially flat 
central parting bead portion 13, and whose outer edges are inturned to 
form terminal flanges, an inner terminal flange 14 protruding from the 
inner edge of the inner sash-facing panel 12A, and an outer terminal 
flange 16 protruding from the outer edge of the outer sash-facing panel 
12B. Protruding inward toward the two sliding double-hung window sashes at 
the central parting bead portion 13 is an extruded box beam or 
channel-shaped section forming a parting bead, preferably substantially 
rectangular in cross-section and defined by an inner bead panel 17 and two 
bead sidewalls 18 forming a substantially rectangular box configuration as 
illustrated in the figures. The inner bead panel 17 facing the interior of 
the window opening is contiguously joined at the corners 19 of the 
substantially rectangular box cross-section to the inner edges of both 
bead side walls 18. The outer edges of bead side walls 18 may be joined by 
a bridge panel 13A, if desired, as shown in FIG. 2. 
SLANTING WING FLANGES 
Protruding from the inner corners 19 of the parting bead diagonally outward 
toward the sash facing panels 12A and 12B are respective slanted wing 
flanges diverging diagonally from the bead side walls 18. The wing flanges 
21 may be formed as flat panels, arched panels, or bent panels in the form 
illustrated in the figures. 
As shown in FIGS. 3 and 4, the relaxed, undeformed position of wing flanges 
21, predetermined by the extruding die, are characterized by the small but 
ample spacing between the diagonal wing flanges 21 and side walls 18 of 
the parting bead, before window sash 22 is installed between wing flange 
21 and inner terminal flange 14. As illustrated in the figures, the 
thickness "t" of sash 22 fitting between these two flanges causes the 
diagonal wing flange 21 to be resiliently deformed (as at 21A in FIG. 3) 
and urged away from the remote terminal flange 14 and toward the adjacent 
bead side wall 18. As shown in FIGS. 2, 3 and 4, the thickness "t" of sash 
22, relative to the width of sash-facing panel 12A, will normally be 
sufficient to depress the distal edge of wing flange 21 to position 21A, 
against bead side wall 18, limiting the resilient flexing deformation of 
flange 21 and minimizing its further bending deformation. 
SASH BALANCING FORCE 
As indicated in the figures, the force applied by resiliently deflected 
wing flange 21 against sash 22 urges sash 22 against the opposing terminal 
flange 14, providing counteracting forces tending to grip or "squeeze" 
both faces of sash 22--the interior face of sash 22 facing the inside of 
the building in sliding engagement with terminal flange 14, and the 
exterior face of sash 22 in sliding engagement with the resiliently 
deflected wing flange 21. These counteracting tractive forces provide 
weatherstripping sealing along the side edge of the sash, and also provide 
sash balancing force through the frictional engagement of the sash 22 with 
flange 14 and wing flange 21, with the static frictional force balancing 
the weight of the sash in the same manner that counterbalanced sash 
weights or spring sash balances are used to balance the weight of the sash 
itself. 
The preferred flat "bent" shape of wing flanges 21 illustrated in the 
figures comprises a proximal diagonal panel segment 21B protruding 
directly from corner 19 of the parting head, and a contiguous distal 
portion 21C which in its extruded, relaxed condition is substantially 
parallel to bead sidewall 18. Installation of sash 22, deflecting wing 
flange 21 to position 21A, concentrates the tractive force between the 
sash and the flange along the central outer face 21D. This assures that 
the bending moment arm of the deflecting force applied to the proximal 
wing flange panel 21B remains constant, even if long continued use and 
ageing of the extruded plastic body of sash guide 10 should result in some 
reduction of its internal elastic resilience applying the reactive 
tractive force to sash 22. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in the above construction without 
departing from the scope of the invention, it is intended that all matter 
contained in the above description or shown in the accompanying drawings 
shall be interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.