Patent Application
20090188076
The invention pertains to the field of block and tackle sash balances. More particularly, the invention pertains to a block inserted into one end of the block and tackle balance to substantially limit air flow through the jamb channel and the accumulation of dirt within the containment tube of the balance.
Windows and particularly double hung window, i.e., those having two vertically movable sashes, utilize a balance mechanism that is contained within the jamb channel of the window frame to assist with the vertical movement of the sashes. One conventional type of balance is referred to as a block and tackle balance because it uses a combination of a cord, springs and pulleys to provide the progressive tension required to assist with the movement of the sash. A certain amount of air leakage is permitted through, and often designed into, the jamb channel by the weather stripping. The amount of air flow, though, may eventually exceed original design parameters and become detrimental to providing an adequately insulated window.
This problem is particularly critical in windows that use block and tackle balances because the open end of the elongated balance channel must provide enough clearance to permit the cord to traverse freely in and out of the end of the channel as the sash is vertically moved. Moisture, sound and foreign matter, such as fine dirt and dust may enter, which would adversely affect the function of the balance. Certain designs have been attempted to address this problem. In particular, U.S. Pat. No. 4,300,316 provides a “foot seal” that is secured to one end of the balance. This foot seal moves up and down the jamb channel as the sash is moved. U.S. Pat. No. 4,642,845 discloses the use of end caps that close off both ends of the balance tube. These end caps are designed to act as seals for pressurized gas contained within a piston and cylinder balance. One of the key drawbacks to this design is that the entire device must be assembled by the balance manufacturer and should one of the end caps fracture, the seal is compromised causing the balance to fail, necessitating replacement of the entire balance. The replacement of a defective or worn out balance is a costly and destructive process, often requiring replacement of a sizeable portion of the window assembly, especially around the jamb channel. An effective yet inexpensive end seal or block is needed that can be assembled by either the balance manufacturer or the window manufacture after construction of the window assembly.
The present invention consists of a block shaped to fit onto an end of the balance containment tube of a conventional window block and tackle balance. Its purpose is to prevent excessive airflow into and out of the carrier channel of a window frame to control the insulating function of the window frame and to substantially prohibit the accumulation of dirt and dust within the balance containment tube. The block is secured to the end of the balance containment tube by a rigid or semi-rigid retainer.
Referring to
The free end of the cord 16 extends out the second end 14 of the block and tackle balance 10 and is secured to a retaining hook 18. The purpose of the retaining hook 18 is to engage an end wall 204 (see
The movement of any balance through a jamb channel can accommodate a certain amount of air exchange that complies with original design parameters. However, excessive wearing of certain components, especially a weather seal, over time results in an unacceptable amount of air exchange between the inside and outside of a building or house. The present invention is a system consisting of a device that provides the dual function of maintaining an acceptable level of air flow through the jamb channel 202 while substantially prohibiting the accumulation of dirt and dust within the containment tube 20 of the block and tackle balance 10. Dust and dirt will eventually compromise the proper function of the pulley and cord system, thus adversely affecting the proper tension requirement and mobility of the sash.
The present invention substantially alleviates these problems by providing an air flow stop in the form of a block 30, which is secured to the second end 14 of a block and tackle balance 10. Optional means may be used to secure the block 30 to the second end 14 of the balance 10, such as by means of an adhesive, but the preferable method is by use of a substantially rigid retainer 32. The retainer 32 consist of a plate portion 34 which abuts the outer surface 36 of block 30. In one embodiment, at least one projection 38, is integrally formed with the retainer 32, and traverses through corresponding holes 40 (see
In the first embodiment, as exemplified by the appended Figures, the end cap 50, has retaining holes 52 that correspond to the at least one projection 38 and the holes 40 in the block 30 (see
Once the block 30 is in abutment with end cap 50, projections 38 are inserted through corresponding holes 40 in block 30 continuing through retaining holes 52 in end cap 50. Tab hooks 39 at the ends of each projection 38 securely snap into place inside mating retaining ledges on the inner surface 56 of end cap 50.
As best shown in
Block 30 may be made from a pliable material that enables it to travel through jamb channel 202 with substantially minimal resistance during the vertical movement of the sash through the jamb channel 202. Such material may consist of a synthetic foam material, having either open or closed cells. It may also consist of various rubber or other polymers, such as any of a variety of acrylics, nitrites, EPDM, and the like. Block 30 may also consist of a rigid or semi-rigid material, such as a metal, any variety of metal alloy or a hardened synthetic resin.
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.
