Patent Application
20110067314
1. Field of the Invention
The invention pertains to the field of window balances. More particularly, the invention pertains to an air dam for a jam channel of a window.
2. Description of Related Art
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 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 positioned on either side of the sash within the window frame assembly and typically form vertical jamb channels to provide a space to permit the sash shoe or carrier to traverse up and down as a sash is raised and lowered. The jamb channels are not well sealed at either their top or bottom and each forms, in effect, a “chimney” that permits air to easily flow upwardly, which compromises the insulating value of the window. Further, dust and other fine particles can enter the jamb channel with the air flow, and can ultimately deposit on the balance system, thereby increasing the force necessary to move the carrier through the channel.
In a conventional curl spring carrier, the end of the spring is attached to the wall of the jamb channel via a fastener, as shown, for example, in U.S. Pat. Nos. 5,353,548 and 5,463,793, most commonly a screw, or the spring is attached to an anchor, as shown, for example, in U.S. Pat. No. 6,990,710. As the sash is manually moved to either open or close the window, the curl spring, which may be coiled up within the carrier, either uncoils as the carrier is moved away from the point of attachment or retracts and recoils within the carrier as the carrier is moved toward the point of attachment. The opening of a window depends on the position of the sash. The upper sash opens by being moved downwardly in the jamb channel and the lower sash opens by being moved upwardly along the jamb channel. The point of attachment and whether the curl spring is coiled within the carrier or is uncoiled in the sash's “closed” position varies with window design.
Windows are subjected to manufacturing standards that mandate specific air flow-through standards for each design. For example, there are varying standards which apply depending upon which region of the country the window is scheduled to be installed. To test a window, a blower is sealably attached to the window by a common duct, usually by cutting a hole into the glass or Plexiglas pane of one of the sashes. Pressurized air is then blown through the duct and any leaks are located and recorded. The minimum standard which all windows must pass is a wind speed of 25 miles per hour (mph). Higher wind speeds must be withstood by windows being installed in many parts of the country. For example, a design pressure of 35 (DP 35), which corresponds to a wind speed of about 143 mph, is typically required for non-coastal applications. DP 55, which corresponds to a wind speed of about 180 mph, is a preferred rating for coastal applications, due to higher wind speeds. Not only must the sash panes be able to structurally withstand this high wind speed, 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 speed standards.
Numerous attempts have been made to try to meet these aggressive wind speed standards, but they have met with only limited success. For example, even if the window holds up to the pressure generated by the wind, the amount of air passing through the jamb channels via a “chimney effect” may be detrimentally excessive. Attempts to block or alleviate these aerodynamic forces often cause unwanted side-effects, such as adding resistance to the movement of the sash, etc. There is a need in the art for an air block that substantially achieves the goal of minimizing air flow through the jamb channel, which has the ancillary benefit of substantially reducing the amount of airborne particles that accumulates within the jamb channel, while adding a minimal or no resistance to raising and lowering the window sash and the attached window balance carrier or shoe in the jamb channel.
The static air dam includes at least one mounting feature, which is preferably at least one hole or slot to allow a fastener, such as a screw, bolt, rivet, weld, or other similar attachment devices, to secure the air dam to a wall of a jamb channel. Air passage through the jamb channel is prohibited or at least substantially inhibited by the static air dam that is designed to approximate the size and dimensions of the cross section of the jamb channel. At least one side of the air dam includes a tab or similar structure for securing the free end of the curl spring of a curl spring balance. The air dam includes integrally formed reinforcing elements that either abut or are adjacent to the side walls of the jamb channel. The air dam preferably includes a pair of flexible projections for engaging ears on the curl spring carrier.
A static air dam is preferably securely attached at a specific location in the jamb channel of a window frame. The air dam has at least one mounting feature to secure the air dam to a wall of the jamb channel. The mounting feature is preferably a hole or slot to allow a fastener, such as a screw, bolt, rivet, weld, or other similar attachment devices to secure the air dam to the wall. Alternatively, the mounting feature may be a snap, a clip, or an adhesive element within the spirit of the present invention. The air dam is preferably affixed to the back wall of the jamb channel, but it may alternatively be secured to either one or both of the side walls of the jamb channel.
Air passage through the jamb channel is prohibited or at least substantially inhibited by the static air dam that is designed to have a substantially rectangular footprint approximating the size and dimensions of the cross section of the jamb channel. The air dam includes a tab or similar structure for securing the free end of the curl spring of a curl spring balance. The free end of the curl spring remains stationary with respect to the window frame, while the curl spring balance traverses up and down the jamb channel as the sash of the window assembly is moved up and down.
The air dam includes reinforcing elements that are preferably integrally formed and either abut or are adjacent to the side walls of the jamb channel. These reinforcing elements help to support the tilt latch of the carrier under higher DP standards and impact conditions resulting from the movement of the sash within the jamb channel. An additional benefit provided by the static air dam is the elimination or substantial reduction of airborne particles that might otherwise enter the jamb channel to contaminate the jamb channel itself and the carrier and balance mechanisms within the jamb channel.
A rib member 24, located below the holes 14, 15, spans the space between the reinforcing elements and eliminates or substantially inhibits air and detritus (i.e. dirt, dust, etc.) transmission through the jamb channel. Alternatively, the rib member 24 may be located above or between the holes 14, 15. In the illustrated embodiment, especially visible in
Two tabs 30 are integrally formed at the upper ends of each of the lateral reinforcing elements 16. Only one tab is necessary for each static air dam, but the illustrated embodiment has two to permit installation of the static air dam 10 in either the left or right jamb channels of a window frame. The free end of a curl spring is secured to the tab 30.
Flexible projections 50 are integrally formed on either side of the rib member 24 to non-permanently engage a curl spring carrier while mounting the sash to the window jamb. The engagement of the carrier to the static air dam 10 provides stability while installing the sash. The projections 50 are flexible so that the curl spring carrier readily disengages from the static air dam 10 once the end of the curl spring has been secured to the tab 30 of the mounted static air dam 10.
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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.
This application claims one or more inventions which were disclosed in Provisional Application No. 61/244,989, filed Sep. 23, 2009, entitled “STATIC AIR DAM”. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61244989 | Sep 2009 | US |
