Patent Application
20120272476
Hung window assemblies generally include a window frame, a lower window sash, an upper window sash, a pair of window jambs, two sets of jamb channels, and at least one window balance device for offsetting the weight of a window sash throughout a range of travel within the window frame. Window balance devices use springs, pulleys, or a combination thereof to balance the weight of the window sash at any position within the jamb channels. In some cases, the springs and pulleys are located within channels or housings that travel with the window sash as it is raised and lowered.
In some window balance devices, most notably block and tackle window balance devices, the channel containing the spring and pulleys is attached to the window sash, and a cord, which connects the pulleys together, is attached to a jamb mounting hook that is connected to a side jamb. One or both of upper and lower sash cams are secured to the sides of a moveable window sash and interact with the top and bottom guides of the window balance respectively. These interacting components, referred to herein as interfaces, engage the window sash with the window balance as the window is raised and lowered.
A prior art window balance upper interface 10 is depicted in
In one aspect, the technology relates to a sash cam having a body adapted to be secured to a window sash, the body including an angled interface surface adapted to contact a top guide of a window balance. In an embodiment of the above aspect, the body includes a sash-contacting surface for contacting the window sash, and wherein the angled interface surface is oriented at an angle to the sash-contacting surface. In another embodiment, the angle is from about 85 degrees to about 15 degrees, from about 70 degrees to about 25 degrees, or from about 65 degrees to about 55 degrees. In another embodiment, the angled interface surface is adapted to contact a projection on the top guide.
In another aspect, the technology relates to a window balance system for a window sash, the window balance system including: a window balance having a balance channel and a top guide connected to the balance channel; and a sash cam having a sash-contacting surface and an angled interface surface, wherein the sash-contacting surface is adapted to be secured to the window sash and the angled interface surface is adapted to contact the top guide. In an embodiment, the angled interface surface is oriented at an angle to the sash-contacting surface. In certain embodiments, the angle is from about 85 degrees to about 15 degrees, from about 70 degrees to about 25 degrees, or from about 65 degrees to about 55 degrees.
There are shown in the drawings, embodiments which are presently preferred, it being understood, however, that the technology is not limited to the precise arrangements and instrumentalities shown.
The description that follows utilizes a block and tackle window balance as an exemplary embodiment of a window balance device that may benefit from the technology described herein. Ramped sash cams such as those described, may also be used on other types of window balance devices to center the window sash in the window frame and eliminate play or slop of the sash. Other such balance devices include constant force balance devices, spiral balance devices, and balances that utilize a combination of balance technologies (for example, those that utilize both block and tackle and spiral balance technology). Additionally, the examples provided herein depict ramped sash cam technology utilized near a top of a window sash, engaging an upper portion of a window sash. It is also contemplated to utilize the technology described herein proximate a bottom portion of a window sash, or elsewhere along the length of the sash, as required or desired for a particular application.
A ramped sash cam 128 is secured to the window sash 114 and includes a body 128′ and a sash-contacting surface 130 that contacts the sash 114 when the cam 128 is secured thereto. The ramped sash cam 128 includes an angled interface surface 132. The angled interface surface 132 is oriented at an angle a to the sash-contacting surface 130, as depicted in
The materials utilized in the manufacture of the ramped sash cam may be those typically utilized for window balance manufacture, e.g., aluminum, zinc, steel, brass, stainless steel, or plastic (such as PVC, polyethylene, nylon, acetal, etc.). Material selection for most of the components may be based on the proposed use of the ramped sash cam. Appropriate materials may be selected for cams subject to certain environmental conditions (e.g., moisture, corrosive atmospheres, etc.).
Although a single top guide/sash cam interface is depicted in the figures, it should be understood that a typical window installation would include one interface on each side of a window sash. Certain window embodiments may benefit from a single ramped sash cam on one side of the sash and a second, standard, sash cam on the opposite side. It is likely, however, that the window sash may not sit properly between the window balances if only a single ramped sash cam is used. In certain applications, however, this may be acceptable. Additionally, although the ramped sash cam is depicted as a discrete structure that is secured to a side of a window sash, it is contemplated that certain window sashes may be manufactured with an angled interface surface integral with the window sash. Another embodiment of the ramped sash cam disclosed herein includes a structure having a side configuration such as that depicted in
While there have been described herein what are to be considered exemplary and preferred embodiments of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.
