Patent Application
20100212110
The invention pertains to the field of windows. More particularly, the invention relates to a device and its corresponding method for installing pre-tensioned spiral balances in the jamb channels of window frames after assembly of the sash by the window manufacturer.
Pretension spiral window balances have advantages over non-pretension balances. Pretension balances have a spiral rod that is pre-wound and set with a certain amount of tension. This saves the window manufacturer having to manually turn or wind the lift force onto the spiral rod of the balance prior to attaching the end of the spiral rod to a window sash. Pretension balances also eliminate the possibility of the window manufacturer applying an incorrect number of windings (lift force) to the balance, which could result in the improper operation or outright failure of the window balance.
When a non-pretension balance is installed into the jamb channel of a window frame, the rod is free to drop below the window sash and the rod end can be accessed for winding the lift force into the balance and then attaching it to the window sash. However, this requires specific tooling and which may be prone to human error. In a pretension balance, the lifting force is machine wound. Then the pre-wound rod is locked in position by the balance manufacturer, by means of the balance spring torque, inside a special pretension balance anchor.
After a pretension balance is mounted within the jamb channel of a window frame, the rod end may not be accessible from below the window sash because it is not free to drop below the bottom end of the sash. This makes it difficult for the window manufacturer to install the balance in the jamb channel and attach the end of the spiral rod to a ledge on the window sash.
There is a need, therefore, for a device to extend the end of the spiral rod so that the spiral rod can be pulled below the sash and secure a clip which is located at the end of the spiral rod onto a ledge on the sash. A conventional window industry balance installation tool can now be attached to the extension device and used to attach the spiral rod end to a ledge on the window sash.
The present device is a spiral rod extender. It increases the length of the end of the spiral rod in a pre-tensioned spiral rod window sash balance and is designed to facilitate the installation of the sash balance by the balance and/or window manufacturer. The spiral rod extender is attached to the end of the spiral rod by the balance manufacturer. It consists of a flattened elongated structural support member to which an elongated spring is securely attached at one end of the spring. The other end of the spring has a pin or stamped upset feature. In its resting state, the spring firmly presses against the structural support member and the pin protrudes through a hole in the structural support member. As the balance is assembled by the balance manufacturer, a pre-set amount of tension is applied to the spiral rod which retains the spiral rod in the spiral rod containment tube during shipment and handling by means of a pretension anchor contained within the closed end of the containment tube.
To install the spiral rod extender onto the end of the spiral rod, the spring and structural support member are urged apart so that the pin is withdrawn from the hole in the structural support member. The end of the spiral rod is then inserted into the end of the spiral rod extender in proximity to the separated spring and structural support member. Upon relaxing the spring, the pin at the spring's end is inserted through a hole in the spiral rod. The pin traverses through the hole in the spiral rod and continues through the hole in the structural support member, thus providing a secure fit between the spiral rod and the spiral rod extender.
At the window manufacturer's assembly facility, the sash is installed into the window frame and the balance is inserted into one of the jamb channels of the window frame. The closed end of the containment tube of the balance is securely fastened to the wall of the jamb. The sash is then urged toward the end of the secured end of the balance, exposing the spiral rod extender. The inventive hook tool is used to grab onto a hole in the end of the spiral rod extender to pull it a sufficient amount out from the containment tube to enable the window assembler to attach a retainer hook, which has been securely fastened to the spiral rod in close proximity to the end which is attached to the spiral rod extender, onto a ledge of the sash, thus securing the balance to the sash. The end of the hook is then removed from the hole in the extension device and is inserted between the structural support member and the spring to urge the pin out of the holes in the structural support member and the spiral rod. The spiral rod extender is then removed from the spiral rod and may be reused by the balance manufacturer or discarded at the option of the balance or window manufacturer.
A conventional spiral rod window balance 10 is shown in
The first end 118 of the elongated structural member 106 is formed into an integral bore 121 that is designed to receive the first end 104 of spiral rod 102. The bore 121 extends only a portion down the length of the elongated structural member 106, for example, for approximately one-third to one-half of the entire length of the elongated structural member 106. The elongated structural member 106 may be fabricated from a stamped metal or metallic-like material such that enough material is retained from the stamping to allow the excess material to be folded over to form the bore 121. The two ends of the folded over excess material do not meet so that a narrow channel 124 separates them. Alternatively, the elongated structural member 106 may be manufactured from a molded material of suitable strength to survive the requirements designed for its use. A button 126, or pin having a smooth or flattened head, is located between the first and second ends of the elongated structural member 106. The shaft 126′ of the button 126 extends through button hole 128 in the elongated structural member 106. The pin 114 at the first end 112 of the elongated spring 108 protrudes through a hole 116 in the elongated structural member 106 within the bore 121.
To install the extension device 100 onto the spiral rod 102, the bore 121 of the first end 118 of the elongated structural member 106 is aligned with the first end 104 of the spiral rod 102. As the spiral rod is inserted into the bore 121, the button 126 is depressed, which urges the elongated spring 108 away from abutment with the elongated structural member 106 and deflects the pin 114 out of hole 116 through the bore 121. The first end 104 of the spiral rod 102 is then able to slide unimpeded into the bore 121 until the hole 130 in the first end 104 of spiral rod 102 aligns with the hole 116 in the elongated structural member 106 and the pin 114 at the end of the elongated spring 108. As pressure is released from the button 126, the pin 114 traverses through both the hole 130 in the first end of the spiral rod 102 and the hole 116 in the elongated structural member 106, thereby non-permanently securing the spiral rod extender 100 to the spiral rod 102.
Referring to
Once the sash hook 142 of the balance 10 is firmly engaged with the interface ledge 160 on the sash 150, the spiral rod extender 100 is no longer needed. To remove the spiral rod extender 100 from the first end 104 of the spiral rod 102, the hooking element 202 of the hook tool 200 is inserted between the elongated structural member 106 and the elongated spring 108, retracting the pin 114 at the first end 112 of the elongated spring 108 from within hole 130 in the spiral rod 102. This then allows the spiral rod extender 100 to easily slide off of the first end 104 of the spiral rod 102 and either be discarded or inventoried for return to and recycling by the window or balance manufacturer.
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.
