Wireworking – Loop forming – Coil springs
Reexamination Certificate
2002-05-22
2004-01-27
Larson, Lowell A. (Department: 3725)
Wireworking
Loop forming
Coil springs
C072S217000
Reexamination Certificate
active
06681809
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for bending an extremity of a torsional spring. More particularly, the present invention relates to a device for bending an extremity of a torsional spring so that said bent extremity of the spring may be used with a plug, such as the ones used for operatively connecting torsional springs to overhead shafts of counterbalancing mechanisms of garage doors and the like.
BACKGROUND OF THE INVENTION
It is known in the art that large, vertical, cable-operated doors, such as commercial and residential sectional garage doors, usually require counterbalancing mechanisms to counterbalance the weight of the door in order to decrease the force required to open the door and also facilitate its closing from a raised to a lowered position. Large sectional garage doors used in commercial and residential applications may be manually or power operated. In either case, but particularly for manually operated doors, counterbalancing mechanisms have been used for many years to counterbalance the weight of the door and control its opening and closing movements so that one person can easily control the operation of the door. Counterbalancing mechanisms are also advantageous for power operated overhead doors since they reduce the power requirements needed for the motor and they lower the structural strength required for the door opening and closing mechanism. In other words, lighter weight, lower cost, door controlling mechanisms may be used if a counterbalancing mechanism is connected to the door to assist it in its opening and closing movements. Furthermore, the provision of a counterbalancing mechanism minimizes the chance of a rapid and uncontrolled closing of the door in the event of a failure of the door opening and closing mechanism, which can result in serious injury or damage.
It is also known in the art that a widely used type of counterbalancing mechanism generally comprises a pair of spaced apart cable drums connected to flexible cables, each cable being in turn connected to a lower opposite side edge of the garage door. The cable drums are usually mounted on an overhead shaft which is supported above the door opening and is connected to one or more torsion springs which are each fixed to the shaft at one end, and secured to a fixed structure, such as the wall for example, at the other end, so that the cable drums are biased to rotate in a direction which winds the cables onto the drums and counteracts the weight of the door connected to the cables. The torsion springs are adjusted to properly balance the weight of the door so that minimal opening and closing efforts are required, either manually or when motor controlled.
It is also known in the art that conventional, low cost adjustment devices used for the above-mentioned type of counterbalance mechanism, and widely utilized in the garage door industry, are generally cylindrical “collars” commonly referred to also as “plugs” (or “cones”) which are connected to the so-called fixed ends of the torsion springs and are thus mounted on the aforementioned shaft for adjusting the deflection of the springs to preset the counterbalance force. The aforementioned plugs usually include one or more setscrews which lock the plugs to the shaft to prevent rotation thereabout except during normal adjustment of the spring deflection. The plugs also usually include sockets for receiving winding bars whereby the springs are manually preset, or “preloaded”, by rotating the plugs with respect to the shaft using the winding bars and then locking the plugs to the shaft with the setscrews. Each plug may also include a slot onto which a corresponding bent free end of the torsion spring is hooked on. These slots are usually T-shaped, and are thus commonly known as “T-slots”. An example of a known winding plug is shown in FIG.
11
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Typically, the shape of the slots of the plugs known in the art allows the introduction of the spring's tail without the use of any tool. Once the spring tail is introduced into the slot of the plug, both the plug and the spring are then introduced onto a shaft and installed on site, after which the plug is pushed towards the spring and then rotated around the spring axis in order to have the spring tail blocked there by the slot of the plug. The combined slot and shaft hold the assembly together without any other accessories. An example of a conventional torsional spring hooked onto a known winding plug mounted onto a shaft of a counterbalancing mechanism according to the prior art is shown in FIG.
12
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An important problem associated with the aforementioned type of counterbalancing mechanism, or with any other type of counterbalancing mechanism which uses plugs for operatively connecting torsional springs to overhead shafts of counterbalancing mechanisms, is that the plugs require the torsional springs to have bent extremities which act as “hooks” so as to be able to be mounted onto the slots of said plugs, i.e. so as to be able to be hooked onto the plugs. Therefore, it would be useful to provide a device would be able to bend an extremity of a torsional spring so that said bent extremity of the spring may be used with a plug of a counterbalancing mechanism.
Another important problem associated with the aforementioned type of counterbalancing mechanism, or with any other type of similar counterbalancing mechanism, is that the spring tail often requires to be bent in a particular manner, generally towards the center axis of the torsional spring and with the bent portion having a certain length, so as to be able to properly cooperate with a given plug of the counterbalancing mechanism. Therefore, it would be useful to provide a device which, by virtue of its design and components, would enable to bend an extremity of a torsional spring in a particular manner so that the bent extremity may properly cooperate with a plug of a counterbalancing mechanism.
Yet another important problem associated with the aforementioned type of counterbalancing mechanism, or with any other type of similar counterbalancing mechanism, is that a garage door installer often has to change or adjust torsional springs on site but is not always equipped with the appropriate equipment necessary to suitably heat and bend the spring extremities of a torsional spring because this equipment is generally quite heavy to carry around and fairly elaborate to operate. Therefore, it would be useful to provide a device which, by virtue of its design and components, would enable an easier, simpler and more cost effective way of bending an extremity of a torsional spring. It would be also useful to provide a device for bending an extremity of a torsional spring, which would not require the use of heat for bending the spring tail, and which would be easily transportable from one site to another.
Another important problem known in the art is that different methods and devices are generally required to bend the extremities of torsional springs having different wire sizes, i.e. torsional springs made of wires whose diameters are different. Therefore, it would be very useful to provide to a single device which, by virtue of its design and components, would be able to bend the extremities of torsional springs having different wire sizes.
Hence, in light of the aforementioned, there is a need for an improved device for bending an extremity of a torsional spring destined to be employed with plugs of counterbalancing systems of garage doors and the like. There is also a need for a device which, by virtue of its design and components, would enable to bend an extremity of a torsional spring in a particular manner so that the bent extremity may properly cooperate with a plug of a counterbalancing mechanism. Furthermore, there is also a need for a device which, by virtue of its design and components, would provide an easier, simpler and more cost effective way of bending an extremity of a torsional spring. Moreover, there is also a need for a device for bending an extremity of a torsional spring, which would not require
Allen Guillaume
Larochelle Philippe
Savard Normand
Canimex Inc.
Larson Lowell A.
Merchant & Gould P.C.
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