The invention pertains to the field of window frames. More particularly, the invention pertains to a moveable device that travels up and down the jamb channel of the window frame with the movement of the sash to impede the transfer of air and debris into and through the jamb channel.
Window frames may consist of either a single sash or two sashes, and are referred to, respectively, as single or double hung windows. A window assembly generally includes a window frame, at least one sash, a pair of opposing window jambs, each jamb having a channel for allowing the vertical travel of each sash, and usually a balance to assist with the raising and lowering of the sash to which it is attached by providing a counterbalance force to the weight of the sash.
The jambs are vertically positioned on either side of the sash within the window frame assembly. Because they must provide a space to permit the sash shoe or carrier to freely traverse up and down, and the jamb channels are not well sealed at either their top or bottom. The vertically positioned channel forms, in effect, a “chimney” that permits air to easily flow upwardly compromising the insulating value of the window. Further, dust or other fine particles can enter the jamb channel, which can ultimately gum up the carrier or at least increase the force necessary to move the carrier through the channel.
In a conventional curl spring carrier, such as is disclosed in U.S. Pat. Nos. 5,353,548 and 5,463,793, the end of the spring is attached to the wall of the jamb channel via a fastener, most commonly a screw. As the sash is manually moved to either open or close the window, the curl spring, which may be coiled up within the carrier, will either uncoil as the carrier is moved away from the point of attachment or it will retract and recoil itself within the carrier as the carrier is moved toward the point of attachment. The opening of a window will depend on the position of the sash. An upper sash will open by being moved downwardly in the jamb channel and the lower sash will be moved upwardly along the jamb channel. The points of attachment and whether the curl spring is coiled within the carrier or is uncoiled in the sash's “closed” position may vary from window design to window design.
Windows are subjected to manufacturing standards that mandate specific air flow through standards for each design. For example, there are a number of different standards which apply depending upon which region of the country the window is scheduled to be installed. A blower is sealably attached to the window by a common duct, usually by cutting a hole into the glass or plexiglass pane of one of the sashes. Pressurized air is then blown through the duct and any leaks are sought out and recorded. The minimum standard which all windows must pass is 25 miles per hour (mph). Higher pressures must be withstood by windows being installed in different parts of the country. For example, a DP (Design Pressure) of 35 is required for non-coastal applications. DP 35 is the equivalent of approximately 143 mph. DP55 is the preferred rating for coastal applications, due to higher wind pressures. DP 55 approximates to 180 mph. As is quite evident, not only must the sash panes be able to structurally withstand this high pressure, but the various moving and interacting elements of each window frame must be built to such tolerances so as to withstand or at least minimize the effects of these wind pressure standards.
Numerous attempts have been made to try to meet these aggressive standards; however they have all met with only limited success. For example, even if the window holds up to the pressure, the amount of air passing through the jamb channels via a “chimney effect” can be excessive. Attempts to block or alleviate these aerodynamic forces often cause unwanted side-effects, such as added excessive pressure to the movement of the sash, etc. What is necessary is an air block that substantially achieves the goal of minimizing air flow through the jamb channel, which also has the ancillary benefit of substantially reducing the amount of dirt particles that might accumulate within the channel, while still allowing the essentially unimpeded movement of the sash through the jamb channel. Further, the block cannot be so obtrusive so as to negatively affect the vertical travel of the sash through the jamb channel.
The device of the present invention is called a dynamic chimney block. It is referred to as being dynamic because it is allowed to move vertically up and down the jamb channel and not interfere with the movement of the carrier. Further, this flexibility in movement allows for greater movement of the sash, which results in a larger window opening.
The main purpose of the dynamic chimney block is to impede or substantially reduce the vertical movement of air through the jamb channel. The reduction in air movement improves the insulating properties of the window and minimizes the amount of dust and fine dirt that might otherwise enter the jamb channel which would result in a progressively increasing force required to move the sash through the jamb channel.
The dynamic chimney block has a vertical structural element to which is integrally secured on one end a planar sealing element which is configured to resemble the cross section of the jamb channel to block vertical air movement. Legs or struts are attached in proximity to the other end of the vertical structural element to insure that the dynamic chimney block remains essentially consistently positioned to provide an air block.
Referring first to
With respect to curl spring carriers, such as 204, an elongated spring is coiled within the body of the curl spring carrier 204. The end of the spring which extends outward from the body of the carrier is secured at a specific location in the jamb channel 202 by a mounting bracket 206 (best shown in
The jamb channel 202 must be large enough to accommodate the dimensions of the carrier. The jamb channel 202 consists of a back wall 202a, opposing side walls 202b, and side wall flanges 202b1 and 202b2. However, due to the size of the jamb channel 202, there is a propensity for air to travel vertically through the channel, creating a “chimney” effect. The air usually travels “up” the jamb channel exiting at the upper end 203 of the jamb channel 202. This results in air leakage, thereby causing a loss of valuable insulating properties. Furthermore, the air can transport dust and other fine dirt particles into the jamb channel 202, which, if allowed to build up, can ultimately impede the movement of the carrier, thereby increasing the force needed to move the sash vertically up and down with respect to the window frame.
In order to solve or at least mitigate the problem described above, the novel device shown in
The dynamic chimney block 100 consists of integrally joined segments that are designed to perform varying functions within the jamb channel 202. The dynamic chimney block 100 consists of a back brace 104 which provides the primary structural support as well as sealing between the side walls of the flanges 202b1 and 202b2. Connected to a first end of the back brace 104 is a sealing panel 102. The plane of the sealing panel 102 is slightly smaller than the cross section of the jamb channel 202 (as defined by elements 202a, 202b(x2), 202b1 and 202b2. Multiple sealing panels 202 may be used as required. This allows the dynamic chimney block 100 to provide a substantial vertical air barrier while minimizing friction that would negatively impact the movement of the sash through the jamb channel. Integrally formed in proximity to a second end of the back brace 104 and pointing in the same direction as the sealing panel 102 is at least one leg 108. Preferably, two legs 108 are present. However, this is discretionary with the designer of the specific dynamic chimney block 100. A reinforcing element 110 may optionally be used to provide additional support between the legs and the back brace 104. If required in order to improve the sealing capabilities of the dynamic chimney block 100, a raised rib 106 may be integrally joined onto the external planar surface 107 of the back brace 104. The width of the raised rib 106 cannot exceed the distance between the edges of the flanges 202b1 and 202b2. In effect, the raised rib 106 seats between the edges of flanges 202b1 and 202b2.
The dynamic chimney block 100 may consist of materials such as plastic that is substantially rigid. It must exhibit some degree of flexure so as not to fracture when it is bent around certain structures in the jamb channel. But, it must be rigid enough to retain positional integrity in the jamb channel. Various conventional plastics and/or elastomers are suitable, such as polypropylene and rigid, closed cell foams.
The method of installing the dynamic chimney block 100 into the jamb channel 202 is best described by following the progression of
With the sash now connected to the curl spring carriers 204, the sash is rotated to the vertical position and is urged downward to close the window. A tilt latch 212 (
One of the key advantages of this invention is that by securing the mounting bracket higher in the jamb channel 202, the maximum vertical movement of the sash is achieved, thereby allowing for a larger window opening. As the closed window is opened by urging the sash upward, the curl spring carrier 204 will eventually contact the dynamic chimney block 100 and push the block 100 to the top of the jamb channel 202. Upon closing of the sash, the curl spring carrier 204 is moved downward and the dynamic chimney block 100 is urged just under the tilt latch 212 by the tilt latch itself.
The ability of the chimney block 100 to move (“dynamic”) achieves the goals of allowing for greater vertical movement of the sash, thereby providing for a larger window opening. In addition, substantially reducing air movement improves the insulating value of the window and minimizes the amount of dust and fine dirt particles that might enter the jamb channel 202.
Even though the chimney block of the present invention is described as being “dynamic”, due to its ability to move vertically along the jamb channel at the urging of the curl spring carrier 204, there may be instances where it is necessary or desirable for the manufacturer or the installer to maintain the chimney block 100 at a set position along the jamb channel. In this instance, an optional hole 10 or other suitable attachment means may be designed into the chimney block 100. In the example shown in
Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.
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Number | Date | Country |
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2119506 | Feb 1997 | CA |
Number | Date | Country | |
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20090277097 A1 | Nov 2009 | US |