Patent Application
20160298369
1. Field of the Invention
In general, the present invention relates to counterbalance systems for windows that prevent open window sashes from moving under the force of their own weight. More particularly, the present invention system relates to the structure of both the brake shoe and the spring mount components of the counterbalance system that interconnect to inhibit the unintentional movement, known as drift, of a window sash that has been fully open.
2. Description of the Prior Art
There are many types and styles of windows. One of the most common types of window is the double-hung window. Double-hung windows are the window of choice for most home construction applications. A double-hung window consists of an upper window sash and a lower window sash. Either the upper window sash or the lower window sash can be selectively opened and closed by a person sliding the sash up and down within the window frame.
The sash of a double-hung window has a weight that depends upon the materials used to make the window sash and the size of the window sash. Since the sashes of a double-hung window are free to move up and down within the frame of a window, some counterbalancing system must be used to prevent the window sashes from constantly moving to the bottom of the window frame under the force of their own weight.
A popular variation of the double-hung window is the tilt-in double-hung window. Tilt-in double-hung windows have sashes that can be selectively moved up and down. Additionally, the sashes can be selectively tilted into the home so that the exterior of the sashes can be cleaned from within the home.
Modern tilt-in double-hung windows are primarily manufactured in one of two ways. There are vinyl frame windows and wooden frame windows. In the window manufacturing industry, different types of counterbalance systems are traditionally used for vinyl frame windows and for wooden frame windows. The present invention is mainly concerned with the structure of vinyl frame windows. As such, the prior art concerning vinyl frame windows is herein addressed.
Vinyl frame, tilt-in, double-hung windows are typically manufactured with guide tracks along the inside of the window frame. Brake shoe assemblies, commonly known as “shoes” in the window industry, are placed in the guide tracks and ride up and down within the guide tracks. Each sash of the window has two tilt pins or tilt posts that extend into the shoes and cause the shoes to ride up and down in the guide tracks as the window sashes are opened or closed.
The shoes contain a brake mechanism that is activated by the tilt post of the window sash when the window sash is tilted inwardly away from the window frame. The shoe therefore locks the tilt post in place and prevents the base of the sash from moving up or down in the window frame once the sash is tilted open. Furthermore, the brake shoes are attached to coil springs inside the guide tracks of the window assembly. Coil springs are constant force springs, made from wound lengths of metal ribbon. The coil springs supply the counterbalance force needed to suspend the weight of the window sash.
Small tilt-in windows have small, relatively light window sashes. Such small sashes may only require a single coil spring on either side of the window sash to generate the required counterbalance forces. However, due to the space restrictions present in modern tilt-in window assemblies, larger springs cannot be used for heavier window sashes. Rather, multiple smaller coil springs are ganged together to provide the needed counterbalance force. A large tilt-in window sash may have up to eight coil springs to provide the needed counterbalance force.
The counterbalance force created by the coil spring is fairly constant. However, there is a slight decrease in the counterbalance force that occurs when the window sash is open to the fullest degree. In this position, the coil springs are nearly fully wound. As such, very little of the coil spring is stressed and is opposing the weight of the window sash. It is for this reason that when a window sash is fully open, it may close slightly without being touched. Gravity can cause a window sash to drift closed. Furthermore, when an upper window sash is open, it creates friction against the lower window sash that it passes. If the lower window sash is open, then the friction can cause the upper window sash to drift open.
A need therefore exists for a system that prevents a window from drifting away from its fully open position. This need is met by the present invention as described and claimed below.
The present invention is a system and method for inhibiting inadvertent movement of a window sash out of a fully open position. The window sash is set in guide tracks that run along the sides of the overall window assembly. The window sash is a tilt-in window with pivot posts that engage brake shoes. The brake shoes travel up and down in the guide tracks as the window sash is moved between a fully open position and a fully closed position.
A stop is mounted within the guide tracks. The brake shoe and the stop have a connector that joins the brake shoe to the stop when the window sash is moved to its fully open position. The connection made the connector is tenuous. The brake shoe is separable from the stop when a closing force is manually applied to the window sash that acts to move the window sash away from its fully open position. The force applied must exceed a threshold level. In this manner, the window sash will remain in its fully open position and will not inadvertently drift closed due to gravity, vibrations, or friction with another window sash.
For a better understanding of the present invention, reference is made to the following description of exemplary embodiments thereof, considered in conjunction with the accompanying drawings, in which:
The features of the present invention counterbalance system can be incorporated into many window designs. However, the illustrations provided only show a few exemplary embodiments of the counterbalance system for the purpose of description. The embodiments illustrated are selected in order to set forth some of the best modes contemplated for the invention. The illustrated embodiments, however, are merely exemplary and should not be considered limitations when interpreting the scope of the claims.
Referring to
The brake shoe 12 rides up and down in the guide track 18 of the window assembly. The brake shoe 12 and the window sash 20 it supports are pulled upwardly within the guide track 18 by the coiled ribbon springs 14. The coiled ribbon springs 14 rotate around spool posts 21 that extend from the brake shoe 12.
A tilt arm 22 extends into the brake shoe 12. The tilt arm 22 clips into the window sash 20, therein interconnecting the window sash 20 with the brake shoe 12. When the window sash 20 is tilted, the tilt arm 22 turns and causes the brake shoe 12 to lock in place in the guide track 18.
When the window sash 20 is opened to its fullest extent, the coiled ribbon springs 14 are nearly fully wound on the spool posts 21. In this fully open position, the brake shoe 12 contacts the stop mount 16. The presence of the stop mounts 16 prevents any further movement of the brake shoe 12 beyond the fully open position. However, the mere presence of the stop mount 16 does not prevent the brake shoe 12 from drifting away from the stop mount 16, therein causing the window sash 20 to move away from its fully open position.
To prevent the brake shoe 12, and the window sash 20 it supports, from drifting away from the stop mount 16, an interconnection is created between the stop mount 16 and the brake shoe 12 that physically prevents the brake shoe 12 from inadvertently drifting away from the stop mount 16. In
The mechanical connector 24 includes a flexible locking finger 26 that protrudes from the first end of the brake shoe 12. The locking finger 26 has a flexible neck 29 and a shaped head 30 that extends from the flexible neck 29. The locking finger 26 and the flexible neck 29 form the male section of the mechanical connector 24. The interconnecting female section of the mechanical connector 24 is formed on the stop mount 16.
The stop mount 16 is anchored to the rear wall of the guide track 18. When the window sash 20 is opened, the brake shoe 12 moves up the guide track 18 until it contacts the stop mount 16. The stop mount 16 is set in a fixed location on the guide track 18 with screws. The stop mount 16 has anchor elements 32 that interconnect with the free ends of the coiled ribbon springs 14. In this manner, the stop mount 16 anchors the free ends of the coiled ribbon springs 14 and the coiled ribbon springs 14 act to bias the brake shoe 12 toward the stop mount 16. This bias counterbalances the force of gravity, which acts to move the window sash 20 away from the stop mount 16.
The female section of the mechanical connector 24 is configured as a depression 34 that is formed into the stop mount 16. The depression 34 presents an inclined surface 36 at the bottom edge of the stop mount 16. The inclined surface 36 extends into the depression 34 and terminates with a ledge 38. When the window sash 20 is fully open, the locking finger 26 from the brake shoe 12 comes into contact with the stop mount 16. The locking finger 26 advances over the inclined surface 36, wherein the shaped head 30 moves over the inclined surface 36 and passes over the ledge 38. The presence of the shaped head 30 latched over the ledge 38 completes the mechanical connector 24 that interconnects the brake shoe 12 and the stop mount 16. The interconnection provided by the mechanical connector 24 is sufficient to prevent the window sash 20 from drifting, due to gravity or contact with another sash. However, the interconnection is tenuous. The mechanical connector 24 can be separated by manually applying a separation force in excess of a designed threshold. The preferred threshold separation force corresponds to a downward force of between one and ten pounds being applied to the window sash 20. Such a downward force will separate the mechanical connector 24 and pull the brake shoe 12 free of the stop mount 16, wherein the window now functions in the traditional manner.
It will therefore be understood that the window sash 20 will operate in a completely ordinary manner until the window sash 20 is opened to its fullest extent. At that point, the brake shoe 12 interconnects with the stop mount 16. This interconnection prevents the window sash 20 from drifting closed. To close the window sash 20, a threshold force must be applied to the window sash 20 in a manner that acts to separate the interconnection. Once the threshold force is reached, the brake shoe 12 will separate from the stop mount 16 and the window sash 20 is free to close.
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It will be understood that the embodiments of the present invention counterbalance system that are described and illustrated herein are merely exemplary and a person skilled in the art can make many variations to the embodiments shown without departing from the scope of the present invention. All such variations, modifications, and alternate embodiments are intended to be included within the scope of the present invention as defined by the claims.
This application is a continuation-in-part of co-pending patent application Ser. No. 15/093,727, which claims the priority of 62/144,898 filed Apr. 8, 2015. This application also claims priority of U.S. Provisional application No. 62/165,177 filed May 21, 2015.
| Number | Date | Country | |
|---|---|---|---|
| 62144898 | Apr 2015 | US | |
| 62165177 | May 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15093727 | Apr 2016 | US |
| Child | 15159780 | US |
