Weatherstripping in a double-hung window

Weatherstripping for a double-hung window includes horizontal and vertical weatherstripping elements arranged so that each horizontal weatherstripping element forms a sliding seal with each vertical weatherstripping element to provide a complete seal in a double-hung window without the need for supplemental crack sealing members.

This invention relates in general to window constructions and more 
particularly to an integrated weatherstripping system for a double-hung 
window providing improved sealing over prior art windows and 
weatherstrips. 
Double-hung windows are particularly difficult to seal against air 
infiltration because of the large number of sliding and compression seals 
required by the combination of two separately movable sashes with a window 
frame. Heretofore, a number of different types of weatherstrips have been 
employed, including flexible sheet metal (bronze) weatherstrips as shown 
in U.S. Pat. No. 2,267,021; flexible wicking as shown in U.S. Pat. No. 
2,367,616; pile fiber weatherstripping as shown in U.S. Pat. No. 
2,751,643; plastic weatherstripping; foam weatherstripping and the like. 
While each of these different types of weatherstrips has provided 
reasonably effective sealing against drafts and the like, they have all 
been prone to leak especially at the corners of the window between the 
upper and lower sash rails and the jambs, and between the ends of the 
meeting rails and the jambs. 
In order to provide more complete sealing, it has been customary to add 
small auxiliary weatherstrip elements at these troublesome points as 
illustrated by U.S. Pat. No. 4,300,316. Such auxiliary elements increase 
the complexity of the overall weatherstripping system and while said to be 
partially effective, do not represent the optimum construction from a 
cost, effectiveness or ease of use standpoint. 
Accordingly, it is an object of this invention to provide a window and more 
particularly a double-hung window, including an integrated 
weatherstripping assembly wherein each horizontal weatherstripping element 
cooperates with each of the vertical weatherstrip elements to provide a 
complete seal. 
It is another object of this invention to provide a weatherstripping system 
for a double-hung window wherein all of the weatherstrip elements are 
easily removable for replacement when required. 
It is yet another object of this invention to provide a weatherstripping 
system employing weatherstripping elements manufactured of compressible 
foam material that can be manufactured inexpensively and in a variety of 
shapes. 
It is a further object of this invention to provide a weatherstripping 
system for a double-hung window that may be used in windows with removable 
sashes. 
It is a still further object of this invention to provide a 
weatherstripping system for double-hung windows wherein the force required 
to move the sashes from a closed position to an open position is reduced 
by an arrangement whereby certain of the horizontally-oriented sash 
weatherstrip elements contact the vertically-oriented jamb weatherstrip 
elements only when the window is closed.

Referring now to FIG. 1, a double-hung window 10 is illustrated including 
the weatherstripping system of this invention. Window 10 includes upper 
and lower sashes 12 and 14, respectively, disposed between side rails 16 
and 18 for slidable movement between raised and lowered positions. Sashes 
12 and 14 also engage upper and lower jambs 20 and 22. 
The cooperation of the various weatherstrip elements with the several 
portions of the window and frame may be appreciated by reference to FIGS. 
2-5 along with FIG. 1 and wherein like elements are designated by like 
reference numerals. 
Vertically-oriented side rail weatherstrip elements 30 (FIGS. 1 and 3) and 
31 (FIGS. 2, 4 and 5) each comprise a compressible foam body 34 preferably 
covered by a plastic or other flexible film 36. Weatherstrips 30 and 31 
each include three generally vertically-oriented sealing faces 38, 40 and 
42 (FIG. 3) for sealing the lower sash 14, the upper sash 12 and the 
meeting rail weatherstrip elements, respectively. 
Side rail weatherstrip elements 30 and 31 are mounted within U-shaped 
channels 46 in jamb liners 50, which liners may be formed in any 
conventional fashion such as by extrusion, and is typically made from 
aluminum or plastic and fastened to a wooden core 52. Such jamb liners are 
conventional and as such, form no particular part of this invention except 
as they cooperate with weatherstrip elements of the invention. 
Side rail weatherstrip elements 30 and 31 are formed by conventional means 
as described, for example, in U.S. Pat. Nos. 3,700,368 and 3,781,390, the 
disclosures of which are herein incorporated by reference. Side rail 
weatherstrip elements 30 may be attached to jamb liners 50 by providing 
weatherstrip element 30 with a rigid backing member for press fitting into 
liner 50. At least the sealing faces of weatherstrip elements 30 and 31 
are preferably covered with a low friction polyethylene covering for 
minimizing the force required to raise and lower sashes 12 and 14. 
Top rail and bottom rail weatherstrip elements 60 and 70, as seen in FIGS. 
2 and 4, respectively, each include anchoring portions 62 and 72 
insertable in slots 64 and 74 in the upper and lower rails 66 and 76 of 
the upper and lower sashes 12 and 14, respectively. Each of these 
weatherstrip elements preferably includes a compressible foam body 
surrounded by a flexible film formed in substantially the same manner as 
hereinabove discussed in connection with elements 30 and 31. When the 
various weatherstrip elements of this invention are formed in a continuous 
process and cut to length, the ends of the weatherstrip elements, where 
the compressible foam is exposed, may be treated by dipping in wax or a 
similar sealing material to seal the ends so that water is not absorbed by 
the foam. 
Each of top rail weatherstrip element 60 and bottom rail weatherstrip 
element 70 forms a sliding seal with side rail weatherstrip elements 30 
and 31, and a compression seal with a head sill 80 and a bottom sill 82. 
It will be appreciated, by referring to the drawings, that sealing surface 
78 of bottom rail weatherstrip element 70 sealingly engages sealing face 
38 of weatherstrip elements 30 and 31 while surface 68 of weatherstrip 
element 60 sealingly engages sealing face 40 of weatherstrip elements 30 
and 31. 
Referring now to FIG. 5, meeting rail weatherstrip elements 90 and 92 are 
illustrated. Each of sashes 12 and 14 is provided with meeting rails 94 
and 96, respectively. Meeting rail 94 has a centrally-located slot 98 
therein for receiving weatherstrip element 92; and meeting rail 96 has a 
similar slot 100 for receiving weatherstrip element 90. The ends of 
weatherstrip elements 90 and 92 sealingly engage surfaces 42 of 
weatherstrip elements 30 and 31, respectively. While cooperating meeting 
rail weatherstrips 90 and 92 are shown in accordance with this presently 
preferred embodiment of the invention; it will be understood that a single 
weatherstrip element mounted on either of meeting rails 94 or 96 and of 
suitable configuration to sealingly engage the other meeting rail when the 
sashes are in the closed position, may be employed. 
If desired, the weatherstripping in this invention may be modified somewhat 
from the arrangement shown to make raising and lowering of the sashes 
easier. Specifically, side rail weatherstrips 30 and 31 may be mounted in 
such a way as to contact meeting rail weatherstrip elements 90 and 92 only 
when sashes 12 and 14 are in their closed positions. Specifically, 
weatherstrip elements 30 and 31 may be displaced away from the jamb liners 
in the direction normal to slot 46 at the center thereof so that the ends 
of the horizontal weatherstrip elements 90 and 92 contact faces 42 of 
weatherstrips 30 and 31 only when the sashes are in the closed position 
thus reducing friction between the weatherstrips as the sashes are raised 
and lowered. 
While the weatherstripping system of this invention has been illustrated in 
connection with a double-hung window having permanently installed sashes, 
it will be appreciated by those skilled in the art that the invention may 
be equally well employed in connection with a window of conventional 
design having removable sashes, without substantially changing the 
weatherstripping system. This provides a further advantage over previous 
weatherstripping systems where the weatherstrip elements would not allow 
the easy removal of one or more of the sashes without damaging the 
weatherstrip elements. 
While the invention has been shown and described in connection with a 
presently preferred embodiment thereof, those skilled in the art will 
recognize that further modifications and changes may be made therein 
without departing from the true spirit and scope of the invention which is 
intended to be limited solely by the appended claims.