Patent Publication Number: US-6988527-B2

Title: Plug for counterbalancing mechanism, door assembly including the same and method of installing associated thereto

Description:
FIELD OF THE INVENTION 
   The present invention relates to a plug, also known as a cone, an anchor, or a collar, as used in counterbalancing mechanisms of door assemblies, such as garage doors and the like. The present invention also relates to a counterbalancing mechanism provided with such a plug, to the door assembly including the same, as well as to a method of installing the plug onto the counterbalancing mechanism. The present invention is particularly advantageous in that it enables to facilitate the installation of a plug onto a torsion spring of a counterbalancing mechanism, for operatively connecting the torsion spring onto a corresponding component of the counterbalancing mechanism, so as to or allow a proper torque transfer between the torsion spring and the corresponding component. The present invention may also be used in other situations requiring the attachment of a torsion spring onto a corresponding component of another type of mechanism or assembly. 
   BACKGROUND OF THE INVENTION 
   It is known in the art that door assemblies, such as commercial and residential garage doors, rolling steel doors, and the like, for example, 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. Door assemblies may be manually or power operated, but in either case, 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 door assemblies since they reduce the power requirements needed for the motor and they lower the structural strength required for the opening and closing mechanism of the door. 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 failure of one of the components of the door controlling mechanism, which can result in personal injury or damage to property. 
   It is also known in the art that a widely used type of counterbalancing mechanism  3 , as used for a typical cable-operated door assembly such as the one illustrated in  FIG. 1  for example, generally comprises a pair of spaced apart cable drums  5  connected to flexible cables  7 , each cable  7  being in turn connected to a lower opposite side edge of the garage door  9 . The cable drums  5  are usually mounted on an overhead shaft  11  which is supported above the door opening and is connected to one or more torsion springs  13  which are each fixed to the shaft  11  at one end, and secured to the wall at the other end, so that the cable drums  5  are biased to rotate in a direction which winds the cables  7  onto the drums and counteracts the weight of the door connected to the cables  7 . Generally, conventional counterbalancing mechanisms  3  include two torsion springs  13  which are usually coaxially mounted onto the overhead shaft  11  and which are opposed to one another. Furthermore, the torsion springs  13  are adjusted by applying tension therein to properly balance the weight of the door  9  so that minimal opening and closing efforts are required, either manually or when motor controlled. The two drums  5  which are used for winding the cables  7  are usually fastened at each opposite end of the overhead shaft  11  and are fixed to the same by means of screws, whose respective ends are in contact with the shaft  11  and exert pressure thereon. 
   It is also known in the art that conventional, low cost adjustment devices used for the above-mentioned type of counterbalancing mechanisms, and widely utilized in the garage door industry and others, are generally cylindrical “collars” commonly referred to also as “plugs”  15  (or “cones”, “anchors”, etc.) which are connected to the so-called fixed ends of the torsion springs  13  and are mounted on the aforementioned shaft  11  for adjusting the deflection of the springs to preset the counterbalancing force. That is, each torsion spring  13  is usually coaxially mounted onto the overhead shaft  11  and is preferably connected with a stationary plug  15   a  at one end and a winding plug  15   b  at the other end. Usually, stationary plugs  15   a  are operatively connected to a fixed structure, such as for example, a support bracket  17  rigidly mounted to the wall. Moreover, winding plugs  15   b  are usually removably fixed to the overhead shaft  11  and are used to operatively connect the torsion spring  13  to the overhead shaft  11  so as to allow a torque transfer between the latter two. Hence, the above-mentioned plugs  15  ensure a mechanical connection between each opposite end of the torsional spring  13  and the support or a shaft, depending on whether they are respectively stationary plugs  15   a  or winding plugs  15   b . The winding plugs  15   b  usually include one or more setscrews which lock the plugs to the shaft to prevent rotation therewith except during adjustment of the torsion spring. The winding plugs  15   b  also typically include sockets for receiving winding bars whereby the springs are often preset, or “preloaded”, manually, by rotating the winding plugs  15   b  with respect to the shaft  11  using the winding bars and then locking the winding plugs to the shaft  11  with the setscrews. 
   Thus, garage doors, rolling steel doors, mini-warehouse doors, and the like, as shown in  FIG. 1 , usually comprise counterbalancing mechanisms  3  to counterbalance the weight of the door  9  in order to decrease the force required to open such door  9  and also facilitate (e.g. control) its closing from a raised to a lowered position. As previously mentioned, in most counterbalancing mechanisms of most door assemblies, whether cable-operated or not, each torsion spring  13  is usually coaxially mounted onto an overhead shaft  11  and is preferably connected with a “stationary plug”  15   a  at one end and a “winding plug”  15   b  at the other end. Usually, stationary plugs  15   a  are connected to a fixed structure, such as for example, a support bracket  17  rigidly mounted to the wall. Winding plugs  15   b  are usually removably fixed to the overhead shaft  11  by means of suitable fasteners and are used to operatively connect the torsion spring  13  to the overhead shaft  11  so as to allow a torque transfer between the latter two. 
     FIGS. 2 and 3  show perspective views of stationary plugs  15   a  according to different embodiments of the prior art, and  FIG. 4  shows a side view of stationary and winding plugs being shown cooperating respectively with an extremity of a torsion spring  13  mounted about an overhead shaft  11  of a counterbalancing mechanism  3  according to the prior art. 
   As is known in the art and as can be easily understood when referring to  FIGS. 2–4 , the ends of the torsion spring  13  are generally attached onto the plug  15  by either a) positioning a portion of the end of the torsion spring about the collar  19  of the plug and hooking a bent extremity of the spring  13  onto a corresponding hooking slot  21  of the plug  15 , such as the one shown in  FIG. 2 , or b) by placing the plug  15  against the end of the spring  13  and screwing the threaded plug collar  19  into the spring, with a plug  15  such as the one shown in  FIG. 3 . This is particularly disadvantageous in that the above-mentioned way of connecting a conventional plug  15  onto a torsion spring  13  is relatively time-consuming, and very often requires substantial physical effort and/or specific tooling. 
   Also known in the art are the following U.S. patents and patent applications which describe various devices and methods for use with counterbalancing mechanisms of door assemblies: 
   U.S. Pat. No. 6,174,575 B1 (FOUCAULT et al.); U.S. Pat. No. 6,502,281 B2 (FOUCAULT et al.); U.S. Pat. No. 6,485,006 B1 (BEAUDOIN et al.); U.S. Pat. No. 6,327,744 B1 (DORMA); U.S. Pat. No. 6,263,541 B1 (SCATES); U.S. Pat. No. 6,174,575 B1 (FOUCAULT et al.); U.S. Pat. No. 6,134,835 (KRUPKE et al.); U.S. Pat. No. 6,125,582 (MONDRAGON et al.); U.S. Pat. No. 5,865,235 (KRUPKE et al.); U.S. Pat. No. 5,636,678 (CARPER et al.); U.S. Pat. No. 4,519,556 (TIMOSCHUK); 2003/0094248 A1 (MITCHELL); 2002/0043351 A1 (FOUCAULT et al.); 2001/0039761 A1 (SAVARD et al.). 
   None of the above-mentioned documents seems to describe a plug which by virtue of its design and components, enables to be installed quickly and easily onto the end portion of a torsion spring in a clip-like manner, so as to operatively connect the torsion spring onto a corresponding component of the counterbalancing mechanism, and thus enable a suitable torque transfer between the two via the plug. 
   Hence, in light of the aforementioned, there is a need for an improved device and/or method for operatively connecting a torsion spring onto a corresponding component of a counterbalancing mechanism, which would be able to overcome some of the aforementioned problems. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a plug which, by virtue of its design and components, satisfies some of the above-mentioned needs and is thus an improvement over other known plugs and/or methods in the prior art. 
   The present invention is particularly advantageous in that it may be inserted onto a spring without screwing. 
   In accordance with the present invention, the above object is achieved with a plug for a counterbalancing mechanism of a door assembly, the counterbalancing mechanism comprising a torsion spring, said torsion spring having a plurality coils, and an end portion including an end coil and a preceding coil adjacent to said end coil, the plug being used for operatively connecting the end portion of the torsion spring onto a corresponding component of the counterbalancing mechanism for allowing a torque transfer between the torsion spring and said corresponding component, the plug comprising: 
   connecting means for removably connecting the plug onto the corresponding component of the counterbalancing mechanism; 
   a substantially cylindrical collar insertable into the end portion of the torsion spring, the collar having a longitudinal axis and a peripheral side area extending about the longitudinal axis, the peripheral side area including diametrically opposite top and bottom portions; 
   anchoring means disposed on the bottom portion of the peripheral side area of the collar for cooperating with a coil of the end portion of the torsion spring so as to pivotably anchor the collar onto said end portion of the torsion spring; and 
   a clip projecting from the top portion of the peripheral side area of the collar, at a location on the collar substantially diametrically opposite from where the anchoring means are disposed on the bottom portion of the peripheral side area, the clip being shaped and sized for clasping past the end coil of the torsion spring and operatively engaging with said end coil so as to securely mount the plug onto the end portion of the torsion spring in a clip-like manner. 
   According to another aspect of the present invention, there is also provided a counterbalancing mechanism comprising a torsion spring, said torsion spring having a plurality coils, and an end portion including an end coil and a preceding coil adjacent to said end coil, the counterbalancing mechanism further comprising a plug used for operatively connecting the end portion of the torsion spring onto a corresponding component of the counterbalancing mechanism for allowing a torque transfer between the torsion spring and said corresponding component, the plug comprising: 
   connecting means for removably connecting the plug onto the corresponding component of the counterbalancing mechanism; 
   a substantially cylindrical collar insertable into the end portion of the torsion spring, the collar having a longitudinal axis and a peripheral side area extending about the longitudinal axis, the peripheral side area including diametrically opposite top and bottom portions; 
   anchoring means disposed on the bottom portion of the peripheral side area of the collar for cooperating with a coil of the end portion of the torsion spring so as to pivotably anchor the collar onto said end portion of the torsion spring; and 
   a clip projecting from the top portion of the peripheral side area of the collar, at a location on the collar substantially diametrically opposite from where the anchoring means are disposed on the bottom portion of the peripheral side area, the clip being shaped and sized for clasping past the end coil of the torsion spring and operatively engaging with said end coil so as to securely mount the plug onto the end portion of the torsion spring in a clip-like manner. 
   According to another aspect of the present invention, there is also provided a door assembly having a counterbalancing mechanism comprising a torsion spring, said torsion spring having a plurality coils, and an end portion including an end coil and a preceding coil adjacent to said end coil, the door assembly further having a plug used for operatively connecting the end portion of the torsion spring onto a corresponding component of the counterbalancing mechanism for allowing a torque transfer between the torsion spring and said corresponding component, the plug comprising: 
   connecting means for removably connecting the plug onto the corresponding component of the counterbalancing mechanism; 
   a substantially cylindrical collar insertable into the end portion of the torsion spring, the collar having a longitudinal axis and a peripheral side area extending about the longitudinal axis, the peripheral side area including diametrically opposite top and bottom portions; 
   anchoring means disposed on the bottom portion of the peripheral side area of the collar for cooperating with a coil of the end portion of the torsion spring so as to pivotably anchor the collar onto said end portion of the torsion spring; and 
   a clip projecting from the top portion of the peripheral side area of the collar, at a location on the collar substantially diametrically opposite from where the anchoring means are disposed on the bottom portion of the peripheral side area, the clip being shaped and sized for clasping past the end coil of the torsion spring and operatively engaging with said end coil so as to securely mount the plug onto the end portion of the torsion spring in a clip-like manner. 
   According to yet another aspect of the present invention, there is also provided a method for operatively connecting a torsion spring onto a corresponding component of a counterbalancing mechanism of a door assembly, for allowing a torque transfer between the torsion spring and said corresponding component, the torsion spring having a plurality of coils, and an end portion including an end coil and a preceding coil adjacent to said end coil, the method comprising the steps of:
         a) providing a plug such as the one described and exemplified herein;   b) anchoring the anchoring means of the plug onto a coil of the end portion of the torsion spring so as to pivotably anchor the collar of the plug onto said end portion of the torsion spring;   c) pivoting the collar of the plug about its anchoring means so as to rest the clip of the plug against the end coil, at a location on the end coil substantially diametrically opposite to where the anchoring means of the plug are inserted in step a);   d) clasping the clip of the collar past the end coil of the torsion spring and engaging with the same so as to securely mount the plug onto the end portion of the torsion spring in a clip-like manner; and   e) connecting the plug onto the corresponding component of the counterbalancing mechanism for allowing a torque transfer between the torsion spring and said corresponding component.       

   Preferably, step d) comprises the step of i) bending an extremity of the end coil into a slot of the collar. Preferably also, step i) comprises the step of heating the extremity of the end coil prior to bending it into the slot. 
   The objects, advantages and other features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given for the purpose of exemplification only with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a typical door assembly connected to a counterbalancing mechanism provided with stationary and winding plugs according to the prior art. 
       FIG. 2  is a perspective view of a stationary plug according to a first embodiment of the prior art. 
       FIG. 3  is perspective view of a stationary plug according to another embodiment of the prior art. 
       FIG. 4  is a side view of a stationary plug and a winding plug according to the prior art, said stationary and winding plugs being shown cooperating respectively with an extremity of a torsion spring mounted about an overhead shaft of a counterbalancing mechanism according to the prior art. 
       FIG. 5  is a perspective view of a plug according to a preferred embodiment of the present invention. 
       FIG. 6  is perspective view of a plug according to another preferred embodiment of the present invention. 
       FIGS. 7–10  are different side views showing installation stages of a plug onto an end portion of a torsion spring according to the present invention. 
       FIG. 11  is a cross-sectional view taken along line XI—XI of the plug-spring assembly shown in  FIG. 10 . 
       FIG. 12  is a perspective view of a plug according to another preferred embodiment of the present invention. 
       FIG. 13  is a rear plan view of the plug shown in  FIG. 12 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
   In the following description, the same numerical references refer to similar elements. The embodiments shown in  FIGS. 5–13  are preferred. 
   In the context of the present description, the expression “door assembly” includes various types of door assemblies, such as rolling door assemblies (e.g. mini-warehouse doors, commercial rolling steel doors, etc.) and the like. Although the present invention was primarily designed for a garage door assembly, it may be used with other kinds of assemblies, such as fire doors or shutters, or with any other door assemblies provided with counterbalancing, winding, and/or controlling mechanisms requiring a torsion spring to be connected to a corresponding component, as apparent to a person skilled in the art. For this reason, the expression “counterbalancing” and/or “door assembly” should not be taken as to limit the scope of the present invention and includes all other kinds of assemblies or items with which the present invention may be used and could be useful. 
   Moreover, in the context of the present description, the expressions “door” and “assembly”, “plug” and “collar”, “counterbalancing” and “controlling”, “mechanism” and “system”, “winding” and “counterbalancing”, as well as any other equivalent expressions and/or compound words thereof, may be used interchangeably. The same applies for any other mutually equivalent expressions, such as “plate” and “bracket” for example, as apparent to a person skilled in the art. 
   In addition, although the preferred embodiment of the present invention as illustrated in the accompanying drawings comprises various components such as a groove, a slot, a flange, stopper(s), an end covering, socket(s), orifice(s), etc., and although the preferred embodiment of the plug  101  and corresponding parts of the present invention as shown consists of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential to the invention and thus should not be taken in their restrictive sense, i.e. should not be taken as to limit the scope of the present invention. It is to be understood, as also apparent to a person skilled in the art, that other suitable components and cooperations thereinbetween, as well as other suitable geometrical configurations may be used for the plug  101  according to the present invention, as will be briefly explained herein and as can be easily inferred herefrom, without departing from the scope of the invention. 
   Broadly described, the plug  101  according to the present invention, as exemplified in the accompanying drawings, is a plug  101  (also known as “anchor”, “collar” or “cone”) which is devised for facilitating the installation thereof onto a torsion spring  113  of a counterbalancing mechanism  103  of a door assembly. More particularly, the plug  101  is to be used with a counterbalancing mechanism  103  of a door assembly, the counterbalancing mechanism  103  comprising a torsion spring  113 , and the torsion spring having a plurality of coils, and an end portion  105  including an end coil  107  and a preceding coil  109  adjacent to said end coil  107 , as better shown in  FIGS. 7–10 . The plug  101  is used for operatively connecting the end portion  105  of the torsion spring  113  onto a corresponding component (not shown) of the counterbalancing mechanism  103  for allowing a torque transfer between the torsion spring  113  and said corresponding component, as is typically in most counterbalancing, controlling, and/or winding mechanisms  103  of door assemblies and the like. 
   Typically, the corresponding component is an overhead shaft  11  of the counterbalancing mechanism  103  if the plug  101  acts as a winding plug  101   b , whereas the corresponding component may also be a support bracket  17  for example, operatively connected to a fixed structure, such as a wall for example, when the plug  101  acts as a stationary plug  101   a . It is worth mentioning though, as apparent to a person skilled in the art, that the plug  101  according to the present invention may be used for operatively connecting the end portion  105  of a torsion spring  113  of a given mechanism  103  onto any other type of corresponding component of the given mechanism  103  other than the ones described herein, so long as a torque transfer is required between the torsion spring  113  and the corresponding component, whatever said corresponding component may consist of within the mechanism  103 , as apparent to a person skilled in the art. 
   As better shown in  FIGS. 5 and 6 , the plug  101  according to the present invention comprises connecting means  111 , a collar  115 , anchoring means  117 , and a clip  119 . The connecting means  111  are used for removably connecting the plug  101  onto the corresponding component of the counterbalancing mechanism  103 . The collar  115  is preferably substantially cylindrical and is devised to be insertable into the end portion  105  of a torsion spring  113 , and has a longitudinal axis  121  and a peripheral side area  123  extending about the longitudinal axis, as also better shown in  FIGS. 5 and 6 . 
   The anchoring means  117  are disposed on the bottom portion of the peripheral side area  123  of the collar  115  for cooperating with a coil of the end portion  105  of the torsion spring  113  so as to pivotally anchored the collar  115  onto said end portion  105  of the torsion spring  113 , as can be easily understood when referring to  FIGS. 7–10 . 
   As better shown in  FIGS. 5–10 , the clip  119  of the plug  101  preferably projects from the peripheral side area  123  of the collar  115 , at a location on the collar  115  substantially diametrically opposite from that where the anchoring means  117  are disposed on the bottom portion of the peripheral side area  123 . The clip  119  is preferably shaped and sized for clasping past the end coil  107  of the torsion spring  113  and operatively engaging with the same, as better shown in  FIG. 10 , so as to securely mount the plug  101  onto the end portion  105  of the torsion spring  113  in a clip-like manner, as can be easily understood when referring from  FIGS. 7–10 . This is particularly advantageous in that it enables the plug  101  to be mounted quickly and easily onto the torsion spring  113  of the counterbalancing mechanism  103 , without the need for screwing for example, which is very time-consuming and physically demanding. 
   Referring to  FIGS. 5 and 6 , there are shown two examples of plugs  101  according to the present invention, the plug  101  shown in  FIG. 5  being a “stationary plug”  101   a  and the plug  101  being shown in  FIG. 6  being a “winding plug”  101   b , both to be installed on respective ends of the spring  113 , as aforementioned. Each plug  101 , whether stationary or winding, has essentially the same or similar features for insertion (or cooperation) at the corresponding end portion  105  of the spring  113 . Indeed, each plug  101  has anchoring means  117 , which preferably consist of a flange, a tab, or a wing, projecting on one side of the collar  115 , and an opening on the other side of the collar  115 . A clip  119  extends in front of the opening and is adapted for spring insertion as briefly described hereinafter. 
   As better shown in the accompanying drawings, the plug  101  according to the present invention preferably comprises a groove  125  (i.e. opening) disposed on the top portion of the peripheral side area  123  of the collar  115  and positioned adjacent to the clip  119 , as better illustrated in  FIGS. 5–9 . The groove  125  is preferably shaped and sized for receiving a segment of the end coil  107  of the torsion spring  113  when the clip  119  is clasped past the end coil  107  and operatively engaged therewith, as can be easily understood when referring to  FIGS. 8–10 . 
   As better shown in  FIG. 11 , the plug  101  preferably further comprises a slot  127  operatively connected to the groove  125 , the slot extending inside the collar  115  towards the longitudinal axis  121  thereof, for receiving an extremity  129  of the end coil  107  to be bent into said slot  127 , as illustrated. 
   Referring back to  FIGS. 5–10 , the plug  101  preferably further comprises at least one stopper  131  projecting from the top portion of the peripheral side area  123  of the collar, positioned adjacent to the groove  125 , for abutting against the end coil  107  of the torsion spring  113 , when the clip  119  is clasped past the end coil  107 . 
   Referring now particularly to  FIGS. 7–9 , the clip  119  preferably comprises a wedge-like element having a slanted portion  133  shaped and sized for pressure insertion into the end portion  105  of the torsion spring  113  past the end coil  107  thereof. The wedge-like element preferably also has a hooking portion  135  opposite to the slanted portion  133  for engaging with the end coil  107  once the slanted portion  133  is inserted past the end coil  107 , as also better shown in  FIG. 10 . 
   According to the preferred embodiment of the present invention, the anchoring means  117  preferably comprise a flange  137  projecting from the bottom portion of the peripheral side area  123  of the collar  115 , at a location on the collar  115  substantially diametrically opposite from where the clip  119  projects from the top portion of the peripheral side area  123 , the flange  137  being shaped and sized for insertion between the end coil  107  and the preceding coil  109  of the end portion  105  of the torsion spring  113  so as to pivotally anchor the collar  115  onto said end portion  105  of the torsion spring  113 , as can be easily understood when referring to  FIGS. 7–10 . 
   As better shown in  FIGS. 7 and 8 , the flange  137  of the plug  101  is preferably substantially tapered for facilitating insertion of the flange  137  at an angle between the end coil  107  and the preceding coil  109  of the end portion  105  of the torsion spring  113 . 
   It is worth mentioning though that according to the present invention, the anchoring means  117  may take on various other suitable embodiments so long as they enable the collar  115  of the plug  101  to be pivotally anchored onto the end portion  105  of the torsion spring  113 , as apparent to a person skilled in the art. For example, instead of a flange  137 , the anchoring means  117  may comprise a groove (not shown) disposed on the bottom portion of the peripheral side area  123  of the collar  115 , at a location on the collar  115  substantially diametrically opposite from where the clip  119  projects from the top portion of the peripheral side area  123 , the groove being shaped and sized for receiving a segment of the end coil  107  of the torsion spring  113  so as to pivotally anchor the collar  115  onto said end portion  105  of the torsion spring  113 . Moreover, it is worth mentioning that according to another embodiment of the present invention, the anchoring means  117  could consist of an additional clip which would cooperate with the end portion  105  of the torsion spring  113  in a manner very similar to that of the above-described first clip  119 , as apparent to a person skilled in the art. Indeed, a main objective of the present invention is to provide a plug  101  whose components and design enable it to be securely mounted onto the end portion  105  of a torsion spring  113  in a clip-like manner, irrespectively of the shape or form that its corresponding clip  119  and/or anchoring means  117  may take on, as apparent to a person skilled in the art. 
   Moreover, it is worth mentioning that according to the present invention, the collar  115  of the plug  101  need not be substantially symmetrical and/or cylindrical in order for it to carry out its proper functions. Indeed, the collar  115  of the plug  101  according to the preferred embodiments of the present invention is preferably made cylindrical in order to substantially match the corresponding conventional shape of the torsion spring  113  into which the collar  115  is inserted, but it is worth mentioning that the collar  115  may take on various other suitable cross-sectional configurations so long as it is provided with a peripheral side area  123  having substantially opposite top and bottom portions, located on either side of the longitudinal axis  121  of the collar  115 , so as to enable a clip  119  and anchoring means  117  to be disposed respectively on said top and bottom portions, in order to enable the plug  101  to be mounted onto the end portion of the torsion spring in a clip-like manner, as above-discussed, and as apparent to a person skilled in the art. 
   As better shown in  FIGS. 5–6  and  12 – 13 , the collar  115  preferably comprises an end covering  139  provided with at least one hole  141  for receiving a corresponding fastener for fastening the plug  101  onto the corresponding component of the counterbalancing mechanism  103 . Preferably also, according to the preferred embodiment of the present invention, the end covering  139  preferably comprises an orifice  143  for receiving therethrough a shaft (e.g. overhead shaft) of the counterbalancing mechanism  103 , as can be easily understood from a person skilled in the art. Moreover, if the plug  101  according to the present invention acts as a winding plug  101   b , the end covering  139  preferably is provided with at least one socket  145  for receiving a winding tool, such as a winding bar for example, as is well known in the art. 
   Preferably, the various components of the plug  101 , such as the connecting means  111 , the collar  115 , the anchoring means  117 , the clip  119 , etc., are made of one single piece and of one single material. Various manufacturing processes (molding, casting, and the like) and various suitable corresponding materials may be used for fabricating the plug  101  according to the present invention, as apparent to a person skilled in the art. Preferably, the plug  101  is made of a suitable rigid material, such as a metallic material (e.g. steel, etc.), or a hardened polymer, although other suitable materials, such as composite materials, etc., may be used depending on the particular applications for which the plug  101  is intended, and the loads it is subject to, as also apparent to a person skilled in the art. 
   According to another aspect of the present invention, there is also provided a counterbalancing mechanism  103  provided with the above-described plug  101 . According to yet another aspect of the present invention, there is also provided a door assembly having a counterbalancing mechanism  103  provided with the above-described plug  101 . According to yet another aspect of the present invention, there is also provided a method of installing the above-described plug  101  onto corresponding components of a counterbalancing mechanism  103 . 
   Indeed, according to the present invention, there is provided a method for operatively connecting a torsion spring  113  onto a corresponding component of a counterbalancing mechanism  103  of a door assembly, for allowing a torque transfer between the torsion spring  113  and said corresponding component, the torsion spring  113  having a plurality of coils, and an end portion  105  including an end coil  107  and a preceding coil  109  adjacent to the end coil  107 . The method comprises the steps of a) providing a plug  101  according to the present invention, such as the one described and exemplified herein; b) anchoring the anchoring means  117  of the plug  101  onto a coil of the end portion  105  of the torsion spring  113  so as to pivotally anchor the collar  115  of the plug  101  onto said end portion  105  of the torsion spring  113 ; c) pivoting the collar  115  of the plug  101  about its anchoring means  117  so as to rest the clip  119  of the plug  101  against the end coil  107 , at a location on the end coil  107  substantially diametrically opposite to where the anchoring means  117  of the plug  101  are inserted in step a); and d) clasping the clip  119  of the collar  115  past the end coil  107  of the torsion spring  113  and engaging with the same so as to securely mount the plug  101  onto the end portion  105  of the torsion spring  113  in a clip-like manner; and e) connecting the plug  101  onto the corresponding component of the counterbalancing mechanism  103  for allowing a torque transfer between the torsion spring and said corresponding component. 
   Preferably, step d) comprises the step of bending an extremity  129  of the end coil  107  into the slot  127  of the collar  115 . Preferably also, this last step preferably comprises the step of heating the extremity  129  of the end coil  107  prior to bending it into the slot  127 . It is worth mentioning that depending on the particular configuration of the plug  101 , the end coil  107  could have its extremity  129  bent before or after the plug  101  is mounted onto the torsion spring, as will be briefly described hereinafter. 
   According to a preferred embodiment of the present invention, and in normal use, the flange  137  of the plug  101  is first inserted between the last coil  107  of the spring and the coil  109  before, as better shown in  FIG. 7 . The plug is then pivoted around this insertion point, to bring the wedge-like element in contact with the other side of the coil  107 , as better shown in  FIG. 8 . Once in contact, a user (installer, operator, etc.) taps the plug covering  139  with an appropriate tool  147 , such as a hammer for example. The flange  137  is thereby urged between both coils  107 ,  109 , causing them to open while the other side of the coil  107  slips over the wedge-like element, as can be understood from  FIGS. 9 and 10 . 
   Once the spring coil has jumped over the wedge-like element, it rests over the spring opening (i.e. groove  125 ), as better shown in  FIG. 10 . The user then preferably heats the portion of the spring coil over the groove  125  and, with a hammer or any appropriate tool, bends the spring end into the slot  127  of the groove  125 , as better shown in  FIG. 11 . Once the plug  101  is installed on one end of the spring  113 , the user repeats the above operations for the opposite spring end using the complementary type of plug (stationary or winding). The spring  113  is then ready to be mounted around a shaft, for example, and to be used to counterbalance a garage door or any weight to be counterbalanced. 
   It is worth mentioning that several modifications could be made to the plug  101  without departing from the scope of the present invention. Indeed, the plug  101  according to the present invention may also be designed inversely with respect to the above-described embodiment. In such a case, the spring end would be bent before insertion of the plug  101  in the spring  113 . The plug  101  would have no flange  137 , tab, or wing, but instead, would have an embossment and a wedge-like element on the opposite side of the plug&#39;s groove  125 . The insertion of the plug  101  would be done in the reverse way to the way described previously. A bending tang would be inserted in the spring hole and then the plug  101  would be rotated around this new point until the other spring side touches the plug with the special embossment shape. Then, the user would drive the plug  101  into the spring  113  using a hammer or any appropriate tool  147 . 
   As may now be better appreciated, the present invention is a substantial improvement and presents several advantages over devices and/or methods known on the prior art. Indeed, the present invention may be used in the garage door industry, with new door assemblies or existing door assemblies. The plug according to the present invention is particularly advantageous in that, by virtue of its design and components, as explained hereinabove, the plug  101  may be mounted onto the end of the torsional spring  113  in a clip-like manner, which reduces the installation time and physical requirements which would likely to be needed otherwise with conventional plugs  15  such as the ones illustrated in  FIGS. 2 and 3 . 
   Of course, numerous modifications could be made to the above-described embodiments without departing the scope of the invention, as defined in the appended claims.