This invention relates to the field of window sash balances. More particularly, it relates to a device for forcibly engaging the balance against the side of the sash to reduce the friction between the balance and the jamb channel generated by any friction inducing forces that are produced by the balance pulling on the carrier.
Balances are located in the jamb channels of window frames and are designed to assist with the raising and lowering of the sash by equalizing the gravitational forces acting upon the sash at all times. One of the problems associated with many balances, including block and tackle and spiral balances, is that they exert a force upon the carrier that results in an increase in frictional forces between the carrier and the jamb channel. For example, spiral balances are designed to equalize the weight of the window by using a torsion spring wound around a spiral rod which, in turn, is attached to a carrier to assist with the raising and lowering of the sash. As the sash is moved up or down, the spiral rod turns, as does the torsion spring. As a result of the increasing torsional forces created by the turning of the torsion spring as the rod is pulled from the carrier, combined with the fact the carrier does not necessarily correspond precisely to the size of the cross section of the jamb channel, the carrier tends to “twist” within the jamb channel, thereby creating friction between the carrier and jamb channel. This friction results in an increase in the force required to operate the window sash.
Block and tackle balances exert a different force upon the carrier, often referred to as a “lever-fulcrum” force. While different from the torsional force exerted by a spiral rod balance, a lever-fulcrum force nonetheless also causes in an increase in the frictional force between the carrier and the jamb channel.
It is therefore desirable to eliminate or substantially reduce the friction between the carrier and the jamb channel caused by the undesired forces exerted by a balance during window sash movement while not adversely affecting the easy installation and removal of the sash from the window frame.
The present invention consists of a carrier assembly, which is allowed to traverse up and down the jamb channel with the sash. The carrier assembly contains a carrier, a carrier encasement element and a sash latch. The carrier is attached to the extendable or free end of a window balance. With spiral rod balances, one end of the carrier is attached to the free end of the spiral rod. With block and tackle balances, a hook extends from the balance to attach to the carrier. The other end of the carrier contains a substantially horizontally oriented platform having a ledge for sustaining the weight of the sash. The weight of the sash is transferred onto the platform of the carrier. A sash bracket is either permanently or non-permanently secured to the side of the sash that faces the jamb channel.
As mentioned in the background, the extension of the spiral rod of a spiral rod balance exerts an undesired torsional force on the carrier which causes the carrier to twist within the jamb channel thereby increasing friction between the carrier and the jamb channel. With a block and tackle type balance, the type of undesired force acting on the carrier is a lever-fulcrum force. The present invention eliminates or substantially reduces the frictional interaction between the carrier and the jamb channel by translating these undesired forces from the balance into a force urging the carrier into firm engagement with the side of the sash. The carrier is thus referred to hereinafter as a “side load” carrier because the undesired force is converted into a load forcibly urging the carrier against the side of the sash. The transfer of the undesired force exhibited by the balance into a side load force facilitates the vertical movement of the carrier within the jamb channel by the window operator.
A sash latch hingedly attached to the carrier secures the side load carrier to the sash bracket once the sash is installed on the window assembly. In order to install the sash in the window frame, the sash is positioned such that the sash latch is attached to the sash bracket. Conversely, when the removal of the sash is required, the sash latch is unhooked from the sash bracket and hooked into slots or holes at one of a plurality of pre-determined locations on the wall of the jamb channel to hold the carrier in place, thus allowing the sash to be removed from the window frame.
Referring to
The carrier 12 has a hook segment 16 at its upper end. While the carrier assembly 10 may be used with any balance that generates an undesired force on the carrier, the following description focuses on spiral rod balances which exhibit a torsional force on the carrier. To install the carrier assembly 10, the end of the spiral rod 101 (see
Carrier encasement member 32 contains carrier 12. The cross section of the encasement member 32 approximately corresponds to the size and dimensions of the cross-section of the jamb channel. The upward pull of the spiral rod balance on the carrier 12 urges the carrier 12 toward the side of the sash 14 until contact is made between shoulder portions 34a and 34b (
As the spiral rod 101 is extended further from the balance, the torsional force exhibited by the torsion spring increases. The increasing torsional force is translated into a progressively increasing force urging the side load carrier 10 into increasingly firmer engagement against the sash bracket 18 or the side of the sash. The engagement of the carrier 12 against the side of the sash 14 effectively communicates the inherent torsional force of the spiral rod balance into a force directing the carrier 12 and the carrier encasement element 26 into firm engagement with the sash 14. The transmission of the torsional force from the torsion spring through the spiral rod into a force directing the carrier toward the side of the sash effectively reduces or substantially eliminates the friction that would have otherwise developed between the jamb channel and the carrier caused by the twisting motion of the carrier.
This process is simply reversed to install the sash into the window frame. The spiral rod balance is first installed within the jamb channel, traditionally, by securing the upper end of the balance to the jamb channel by a screw, rivet or other conventional means. Then, the spiral rod 101 of the balance is extended to be connected with the carrier 12. By inserting protrusions 46 of the sash latch 40 into slots 47 in the wall of the jamb channel, the carrier is non-permanently held at a pre-determined location along the jamb channel. Next, the sash is manipulated so that the sash bracket 18, already secured to the sash, is seated on the horizontal platform 24. The sash latch 40 is then pivoted away from engagement with slots 47 in the wall of the jamb channel to engage a latch engagement element 50 of sash bracket 18, as 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.
This application claims one or more inventions which were disclosed in Provisional Application No. 61/101,694, filed Oct. 1, 2008, entitled “Carrier and Balance Attachment System For Side Loading Sash Windows”. 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 | |
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61101694 | Oct 2008 | US |