Abstract:
A support assembly and method is provided for suspending lightweight tools or other objects, such as hairdryers and the like. The assembly provides support and in particular embodiments, electrical power to the object suspended. In addition, the assembly provides management of the cord. Elevation of the object may be adjusted within a predetermined range of motion. The assembly exerts an upward force on the object that varies depending upon the elevation. This variable force is calibrated to provide the object with a uniformly weightless or virtually weightless “feel” nominally throughout the range of movement. The assembly is provided with low friction and low inertia, so that an object may be rapidly and easily moved between various elevations with little effort and little drag. The amount of force exerted on the object by the assembly may be adjusted.

Description:
RELATED APPLICATION 
     This application is related to, and is a Continuation-In-Part of U.S. patent application Ser. No. 09/818,162, entitled Tool Support, filed on Mar. 27, 2001 now abandoned, which is fully incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     This invention relates to retractable overhead tool supports, and more particularly to a low-drag overhead support for lightweight hand-held tools such as hairdryers. 
     2. Background Information 
     In various industries, hand tools and other utilitarian devices are used by workers on a daily basis. Many of these devices are heavy, and require considerable arm strength to lift, hold in place, and maneuver. Weight compensating suspension devices may be desired to support relatively heavy objects from above, such as to support engine blocks and the like in automobile assembly lines. These devices enable the heavy objects to be conveniently moved to or along the production line, enabling workers to rotate them for convenient access, e.g., to attach components, or to lower them into position, such as into an engine compartment of an automobile. In order to support such heavy objects, these suspension devices may be fabricated from relatively heavy components to provide them with requisite structural integrity. These suspension devices, by virtue of their intended use and structural requirements, therefore tend to have relatively high inertial mass. Such devices also tend to exhibit relatively high frictional forces during use. 
     As mentioned above, the supported objects are themselves heavy and as such, are typically moved into desired position slowly, and once so positioned, e.g., at a desired elevation within an assembly line, or within an engine compartment of an automobile, are seldom moved elevationally again, if at all. Accordingly, for such applications, the mass, inertia, and friction of the suspension device is of little adverse affect. 
     However, such suspension devices are less than optimal for use with relatively lightweight objects, such as hairdryers and other hand tools, which have relatively low mass, and which are often moved rapidly between various elevations. For example, hair stylists use hand-held hair dryers, which often must be held for extended periods of time and maneuvered quickly and repetitively between various elevations, sometimes in tandem with a hairbrush while drying or styling. 
     Even when appropriately scaled down in size to compensate for the lighter weight of such objects, conventional suspension devices of the type described above have generally proven deficient in one or more respects. For example, such devices tend to either provide too much, or too little compensating (e.g., upward) force and the cords used to attach these devices to the supported object tend to bind during rapid elevational changes (i.e., during rapid raising and lowering). Furthermore, during such rapid elevational movement, such as during the hair styling/drying action described above, there may be a lag between raising the hairdryer, and the corresponding retraction of the cord. This lag may result in the cord becoming alternately loose, and then taut, to provide non-uniform tool support which may be disruptive to the user. Moreover, the momentary lag may result in a subsequent retraction at an excessive rate of speed, as the device attempts to reel in ‘slack’ in the cord. Alternatively, the device may attempt to retract the cord even as the user attempts to lower the object, which may be further disruptive, and may place undue stress on the user&#39;s wrist and on various components of the suspension device, etc. This uneven application of force generated by such a lag may also result in components of the device disadvantageously cocking or jamming. 
     It is therefore desirable to provide an improved suspension apparatus for lightweight objects such as hairdryers and other hand tools, which renders them apparently or virtually weightless, while enabling them to be frequently and quickly moved between various elevations while also providing lateral freedom of movement. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a multi-elevational hairdryer support includes a frame configured for mounting to a ceiling, and a drum rotatably coupled to the frame for rotation about a central axis, the drum having an exterior frusto-conical surface. A helical channel extends along the frusto-conical surface, a coiled spring is disposed to bias rotation of the drum, and a cord is coupled at a proximal end thereof to the drum. A hairdryer is coupled to a distal end of the cord, which is configured to supply electrical power to the hairdryer. The helical channel windingly receives the power cord therein, so that it may be alternately wound and unwound with and against the bias of the spring as the hairdryer is respectively raised and lowered. The drum is configured for moving axially during the alternate winding and unwinding. The cord alternately exits and enters the helical channel via an axially stable point during the alternate unwinding and winding. The spring is coupled to the drum at an axially stationary location which is orthogonally aligned with the entry and exit point relative to the axis. The spring is also configured for remaining axially stationary during the axial movement of the drum. 
     In another aspect of the invention, a low-drag counter-balance apparatus is provided for offsetting a constant force between two points of reference, over a range of movement, the points of reference respectively defining a point of attachment to the force and an axis of rotation. The apparatus includes a drum configured to rotate about the axis of rotation, and a spring operatively engaged with the drum to bias rotation of the drum, the drum having a surface defining a helical path thereon. A cord is coupled at a proximal end thereof to the drum, the cord being coupled at a distal end thereof to the force. The cord is configured to be alternately wound and unwound about the drum along the helical path during the rotation of the drum, respectively with and against the bias. An entry/exit location is provided, where the cord alternately engages and disengages the drum during the winding and unwinding; and the entry/exit point and the spring are configured for being axially stationary relative to one another during the winding and unwinding. 
     In a yet further aspect of the invention, a low-drag multi-elevational hairdryer support includes a frame configured for mounting to a ceiling, a shaft disposed on the frame, low-friction rolled threads disposed along a first portion of the shaft, a substantially smooth low-friction spring support disposed concentrically with an other portion of the shaft, the spring support having a lubricious outer surface configured to slidably support a spring concentrically disposed therewith. A drum is provided with an integral self-lubricating inner threaded bore, the threaded bore disposed in rotational engagement with the low-friction rolled threads, the drum also having an exterior frusto-conical surface. A helical path extends along the frusto-conical surface, and a coiled spring is disposed to bias rotation of the drum, the spring having a first number of coils concentrically superposed with the spring support, and disposed in axially spaced relation to one another, so that the coils are free from mutual engagement during rotation of the drum. The helical path extends for a second number of revolutions about the drum, so that the ratio of the first number of coils to the second number of revolutions is at least 11:1. A cord is coupled at a proximal end thereof to the drum, and a hairdryer is coupled to a distal end of the cord, the cord configured to supply electrical power to the hairdryer. The helical path is configured to windingly receive the cord thereon, the cord configured for being alternately wound and unwound with and against the bias of the spring as the hairdryer is respectively raised and lowered. The support has a drag force opposing elevational movement of the hairdryer of less than 0.5 pounds (0.2 kg). 
     Aspects of the invention also include a method for offsetting a constant force between two points of reference, over a range of movement, the points of reference respectively defining a point of attachment to the force and an axis of rotation. The method includes configuring a drum to rotate about the axis of rotation, operatively engaging a spring with the drum to bias rotation of the drum, providing a surface defining a helical path thereon, and coupling a proximal end of the cord to the drum. The method further includes configuring a distal end of the cord for coupling to the force, configuring the cord for being alternately wound and unwound about the drum along the helical path during the rotation of the drum, respectively with and against the bias, providing an entry/exit location where the cord alternately engages and disengages the drum during the winding and unwinding; and configuring the entry/exit point and the spring for being axially stationary relative to one another during the winding and unwinding. 
     In another aspect of the invention, a multi-elevational hairdryer support includes a drum disposed to rotate about a central axis. A coiled spring is disposed to bias rotation of the drum, and a cord is coupled at a proximal end thereof to the drum. A hairdryer is coupled to a distal end of the cord, which is configured to supply electrical power to the hairdryer. The drum windingly receives the power cord thereon, so that it may be alternately wound and unwound with and against the bias of the spring as the hairdryer is respectively raised and lowered. The drum is configured for moving axially during the alternate winding and unwinding. The cord alternately exits and enters the helical channel via an axially stable point during the alternate unwinding and winding. The spring is coupled to the drum at an axially stationary location which is orthogonally aligned with the entry and exit point relative to the axis. The spring is also configured for remaining axially stationary during the axial movement of the drum. 
     In a still further aspect, an adjustable apparatus is provided for offsetting the weight of a hairdryer and cord over a range of movement. The apparatus includes a drum configured to rotate about an axis of rotation, a spring operatively engaged with the drum to bias rotation of the drum, and a cord coupled at a proximal end thereof to the drum, the cord coupled at a distal end thereof to the hairdryer. The cord is configured to be alternately wound and unwound about the drum, respectively with and against the bias. A tension adjuster is coupled to the spring, and is configured to adjust the bias over a range of from 0-100% of the weight of the hairdryer and cord. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other features and advantages of this invention will be more readily apparent from a reading of the following detailed description of various aspects of the invention taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is an elevational view of an embodiment of the present invention, in conjunction with a hairdryer shown on a reduced scale; 
     FIG. 2 is another view of the embodiment shown in FIG. 1; 
     FIG. 3 is an elevational, cross-sectional view of portions of another embodiment of the present invention; 
     FIG. 4 is an exploded cross-sectional view of the embodiment of FIG.  3 ;. 
     FIG. 5 is an elevational view of another embodiment of the present invention; 
     FIG. 6 is a front view of a portion of the embodiment shown in FIG. 5; 
     FIG. 7 is an elevational cross-sectional view of portions of the embodiment shown in FIG. 5; 
     FIG. 8 is a top view, with portions shown in phantom, of portions of the embodiment of FIG. 5; 
     FIG. 9 is a view similar to that of FIG. 8, of portions of an alternative embodiment of the present invention; 
     FIG. 10 is an elevational view of the embodiment of FIG. 9; 
     FIG. 11 is a front view of the embodiment of FIG. 10; and 
     FIGS. 12A-12G are elevational schematic views of various drum configurations useful in accordance with various embodiments of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized. It is also to be understood that structural, procedural and system changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. For clarity of exposition, like features shown in the accompanying drawings shall be indicated with like reference numerals and similar features as shown in alternate embodiments in the drawings shall be indicated with similar reference numerals. 
     Where used in this disclosure, the term “axial” when used in connection with an element described herein, refers to a direction relative to the element, which is substantially parallel to axis of rotation a when the element is installed such as shown in FIG.  1 . Similarly, the term “transverse” refers to a direction substantially orthogonal to the axial direction. The term “drag”, as used herein, refers to forces tending to resist the elevational changes of an object supported by embodiments of the present invention. These “drag” forces may include friction and inertia exhibited by various components of these embodiments. 
     An aspect of the present invention was the realization that lack of success using conventional counter-balancing suspension systems was related to the relatively high drag, e.g., inertia and friction, associated with such devices. Moreover, it was found that even when such systems are scaled-down in size in an attempt to accommodate lighter weight (e.g., about 1-25 lbs.) suspended objects, the drag forces become a significant, if not overwhelming factor, particularly for objects in the lower end of this weight range. Indeed, although various componentry may be reduced in size to compensate for lighter weight objects, the drag forces generated by friction and inertia of the moving components, were not proportionately reduced. As such, the ratio of drag forces to the weight of the object became unacceptably high, with the effect of exacerbating the ‘lagging’ problem associated with quick elevational movements as described hereinabove. 
     Embodiments of the present invention address the aforementioned drawbacks by providing a low drag (low inertia, low friction) aerial suspension system configured for nominally weightlessly supporting a lightweight object (i.e., in the range of about 1 to about 25 pounds, and in particular embodiments, about 1-5 pounds), including hairdryers and other hand tools, to enable rapid elevational movements. In addition, these embodiments provide a convenient system for controlling power cords associated with such tools, since any excess cord not needed to support the object in its current position is coiled automatically. The cord is managed to nominally eliminate binding during extension, nor bunching during retraction. These embodiments also provide nearly uniform compensatory (upward) force throughout the operational range of cord extension. These embodiments also provide for conveniently storing the suspended objects. For non-electrical objects, the electrical cord can be replaced with a support cord, and the mechanism for bringing power to the cord need not be present. 
     In addition, the amount of force necessary to extend the object may be adjusted. Applying a relatively slight amount of upward lift on the object may initiate retraction of the cord. Furthermore, cord retraction may be stopped at any position simply by removing the upward lift on the object. The object may be retracted to a preset “home” position that requires additional force to dislodge the object therefrom. Embodiments of the present invention also advantageously provide support for a tool such as a hairdryer, while providing it with six degrees of freedom (i.e., x, y, z, θ x , θ y , and θ z ) of movement. 
     Turning now to the Figures, one embodiment of the present invention is shown in FIGS. 1 and 2 as suspension system  200 . System  200  includes a drum  1  configured to rotate about a central axis a and a spring  4  operatively engaged with the drum to bias rotation of the drum about the axis. Drum  1  includes an exterior surface  202 , which, though not required, in the embodiment shown is substantially frusto-conical. Surface  202  defines a helical path  204  there across, which, in this particular embodiment, is configured in the form of a helical channel disposed within surface  202 . Several alternative drum configurations, e.g., in which surfaces or portions thereof are not frusto-conical, and/or the paths or portions thereof are not helical or are not defined by a channel, are discussed hereinbelow with respect to paths  204 B- 204 G of FIGS. 12B-12G. 
     As shown, a proximal end of a cord  2  is fastened to drum  1 , and is configured for being alternately wound and unwound about drum  1  along helical path  204  as the drum rotates about axis a. During this winding and unwinding, cord  2  enters and exits path  204  (i.e., the cord engages and disengages the drum) at entry/exit point  206 , and extends to a distal end fastened directly (or via a connector  3 ) to an object such as a hairdryer  208 . In the particular embodiment shown, entry/exit point  206  and spring  4  are axially stationary relative to one another during the winding and unwinding of cord  2 , and in this particular embodiment, both point  206  and spring  4  are axially stationary, e.g., while the drum slides axially, as discussed in greater detail hereinbelow. Thus, although point  206  will move axially relative to the drum  1  as the drum rotates, point  206  remains stationary relative to axis a and to a user. Such axial stability advantageously reduces the overall inertia (and thus lowers the drag) of apparatus  200  by minimizing both the number of moving parts and the extent of movement of those parts. This axial stability also nominally eliminates offset torque on the drum to further reduce drag on the apparatus. 
     Optional aspects of these embodiments include disposing the drum engaging portion  210  of spring  4  in substantial transverse (radial) alignment with entry/exit point  206 . Such alignment effectively precludes the formation of an axially extending moment arm between the application of opposite, compensating, forces applied at these locations. The skilled artisan will recognize that such configuration will effectively minimize or substantially eliminate any propensity for the drum  1  and/or spring  4  to cock or twist relative to axis a during rapid elevational movements of the object. 
     Turning now to FIGS. 1 and 2 in greater detail, embodiment  200  may further include a mandrel  5 , a thrust plate  8 , a torque converter  9 , a slip ring assembly  11 , and a spring tension adjuster  15 , all disposed on a threaded main shaft portion  6 . As shown, thrust plate  8  may include a nut at its center, configured to threadably receive the threaded shaft portion  6  therein. Thrust plate  8  is rigidly coupled to drum  1  so that the drum rotates with plate  8  about shaft portion  6 . As mentioned above, drum  1  may include a frusto-conical exterior surface  202 , which optionally includes a helical channel  204  configured to receive a suitably sized cord  2  therein. 
     In desired embodiments, drum  1  is formed as a hollow annulus, with an interior surface having a plurality of axially extending bearing rods  12  disposed in spaced relation thereon. As also shown, torque converter  9  is configured as a disc having a central sleeve  9 B sized to slidably receive shaft portion  6  therein. Converter  9  also includes a series of circumferentially spaced cutouts  9 A sized and shaped to slidably engage the bearing rods  12 . This sliding engagement of the rods  12  with the cutouts  9 A serves to rotationally couple drum  1  to the torque converter  9 , while enabling the drum  1  to slide axially relative to the converter  9 . Moreover, the sliding fit of sleeve  9 B enables torque converter  9  to rotate relative to shaft portion  6 , without traveling axially relative thereto. Axial movement may be prevented, for example, by use of retainer clips  80 . Torque converter  9  also includes a circular ridge  9 C concentric with the main shaft portion  6 . The radially innermost edge of the circular ridge  9 C is sized to matingly engage one end of mandrel  5 , while the radially outermost edge of the circular ridge  9 C may be sized to matingly engage with an inner diameter of one end of spring  4  (FIG.  2 ). The ridge  9 C and/or spring  4  are preferably sized and shaped to provide a snug fit, and the spring is securely attached thereto in any convenient manner sufficient to nominally prevent rotational slippage during operation, as discussed hereinbelow. A support bracket  10  (as shown in FIG. 2) may be used to hold the drum  1  and spring  4  in their desired positions relative to one another. 
     As discussed hereinabove, the frusto-conical surface  202  of drum  1  may be provided with a helical channel  204  configured to hold the cord  2  in a wrapping configuration as shown in FIG.  2 . As shown, the radius of frusto-conical surface  202 , and of the helix formed by channel  204 , increases gradually along the length of the drum. The skilled artisan will recognize that this progressive radius of channel  204  advantageously enables the weight of tool (e.g., hairdryer)  208  to provide progressively increased torque to drum  1  as the cord is unwound, to compensate for increased torque generated by spring  4  as it is moved against its bias. Such compensation may advantageously be used to maintain a substantially neutral or weightless feel to tool  208  during operation of system  200 , as will be discussed in greater detail hereinbelow. The radius of path  204  at particular axial locations may be determined by the particular spring  4  used, the weight of a particular tool  208 , and the added weight of the unwound portion of the cord  2  as it is extended. Moreover, in particular embodiments, the radius may decrease relatively dramatically at the smallest diameter portion of the drum to help retract the tool into the stowed position, as best seen in FIG.  7 . 
     In the embodiment shown, drum  1  and entry/exit point  206  move axially relative to one another during winding and unwinding. In the particular embodiment shown in FIGS. 1 and 2, this is accomplished by the threaded engagement of thrust plate  8  with the threads of shaft portion  6 , so that the drum travels axially along shaft  6  as it rotates. The magnitude of axial movement is determined by the pitch of the threads, which is configured so that the cord  2  will not complete a rotation on top of itself, and thus nominally keep it from binding or jamming as it winds and unwinds. In the particular embodiment shown, the thread pitch is configured to match that of the helical path  204  so that the entry/exit point  206  remains radially aligned with the path  204  throughout the range of drum rotation. 
     In particular embodiments, threads of shaft portion  6  may be configured as conventional multiple start (e.g., 5-start) threads, as may be desired to support the drum. 
     In embodiments in which the cord  2  is an electrical cord, electricity may be transferred from a suitable source, such as a 110 volt AC line voltage source (not shown), to a conventional slip ring assembly  11  having a pair of slidably engagable rings  212 ,  214 . In the embodiment shown, ring  212  does not rotate, but moves axially and may be connected to the source, while the other ring  214  may be integrally fastened to thrust plate  8  to rotate therewith. Ring  214  may then be connected to the proximal end of cord  2 , such as by terminals  52  (FIG.  5 ). In this manner, electricity may be conveniently transferred from a stationary source to the rotatable portions of system  200 . Optionally, as mentioned hereinabove, cord  2  may terminate at its distal end at an electrical plug-type connector  3 , which enables a user to conveniently connect and disconnect the cord to tool  208 . Moreover, although cord  2  has been described herein as an electrical cord, the skilled artisan will recognize that in the event the tool or object does not require connection to a remote electrical source, the cord may simply be used to suspend the tool. The term “cord” is thus not to be construed as limiting, and includes string, rope, chain, wire or other material of sufficient strength and dimension to fulfill the function herein described. 
     As also shown, mandrel  5  is disposed within spring  4 , in spaced, concentric orientation therewith. Mandrel  5  is sized to support the center of the spring  4  during operation of system  200 , to prevent the spring from oversagging at its central portion. In this regard, mandrel  5  may be provided with an outer diameter that is as large as possible, while still being smaller than the smallest inner diameter of the spring  4  when the spring  4  is wound to its operational limit (e.g., when the cord  2  is fully unwound from the drum  1 ). As mentioned hereinabove, the mandrel is supported at one end by ridge  9 C of torque converter  9 . The other end of mandrel  5  is supported by mandrel spacer  5 A which has an inner bearing surface configured to rotatably engage unthreaded shaft portion  6 A as shown. Optionally, one or more additional spacers  5 A′ may also be provided as desired to further support the mandrel  5 . Spacer  5 A is coupled to spring tension adjuster  15 . Adjuster  15 , once adjusted as described hereinbelow, is configured to be stationary during operation of system  200 . This also effectively maintains mandrel  5  in stationary orientation during operation. In the embodiments shown, spring  4  is a coil torsion spring. The adjusting mechanism  15  adjusts the tension of spring  4  by either manually or automatically (e.g., with a suitable stepping motor assembly  216 ) rotating the end of the spring coupled to spacer  5 A. Such rotation effectively applies a predetermined level of preload, either with or against the spring&#39;s bias, to enable a user to fine-tune the amount of force applied by the spring. In this manner, the spring tension may be adjusted depending upon the weight of the accessory  208 . In desired embodiments, the configuration described herein advantageously enables adjuster  15  to adjust the force applied by spring  4  over a range of from 0-100 percent (%) of the combined weight of the accessory  208  and cord  2 . These embodiments thus permit the compensating (e.g., upward) force to be adjusted within a range of from no compensation (the user feels the full weight of the accessory) to a net upward bias equal to its weight. 
     The characteristics of the spring  4  are chosen based on factors such as the weight of the accessory  208  to be suspended, the weight of the cord  2  as it is extended, and the radius of helical path  204 . In addition, the number of coils of spring  4  is preferably chosen to so that the rotation of each individual coil during operation is minimized. For example, it has been found that springs having a number of coils that is at least eleven times the number of revolutions of path  202 , i.e., a ratio of 11:1, is desirable. In such a configuration, during operation, the average rotation of each coil is less than one eleventh that of the drum. In particularly desirable embodiments, a ratio of about 20:1 may be used. A ratio of 30:1 or higher may also be used. It has also been found desirable to coat the spring with a self-lubricating material such as polytetrafluoroethylene (PTFE), e.g., TEFLON® (DuPont Corporation, Delaware) and/or configure the spring so that adjacent coils are spaced from one another, to nominally eliminate any friction therebetween. Various additional factors that tend to contribute to the low drag (low inertia, low friction) aspect of the present invention are discussed hereinbelow. 
     Having described an embodiment of the present invention, operation thereof will now be discussed. As mentioned above, object  208  may be moved elevationally within a predetermined range of motion defined by an upper starting position, in which the cord  2  may be nominally fully retracted, and a lowermost position, in which the cord  2  may be substantially fully extended. In the starting position, the object  208  is suspended from cord  2  which is fully retracted. The object  208  is either in equilibrium (i.e., net bias neither upwardly nor downwardly), or has a net upward bias (e.g., in the event a helical path  204 A having reduced radius (FIGS. 3-5) is used) in this position. If the apparatus is used as only a cord control device, then the spring tension adjuster can be set so that the object can even have a net downward bias and the user feels the weight of the tool if preferred. As the user pulls on the object, the cord  2  is extended and the drum rotates about the main shaft  6 ,  6 A. As the suspended tool  208  is drawn from system  200 , the cord  2  unwinds, which rotates drum  1  and thrust plate  8  coupled thereto. Since the thrust plate  8  is threadably coupled to threaded shaft portion  6 , as discussed above, this rotation serves to move the drum/plate assembly axially along the threaded main shaft portion  6 . As the drum  1  rotates and travels, its bearing rods  12  slide axially relative to cutouts  9 A of torque converter  9 . This serves to rotate the torque converter, which in turn, winds the spring  4  against its bias. As discussed above, the increasing radius of helical path  204 , in combination with the increased weight of the unwound cord  2 , provides increased torque that effectively compensates for the increased torque generated by spring  4  as it winds, so that as perceived by a user, tool  208  remains virtually weightless as it is moved within its range of motion. 
     To reverse this action, a slight lift of suspended tool  208  enables spring  4  to unwind, i.e., in the direction of its bias. This unwinding effectively reverses the rotation of torque converter  9 , which then rotates drum  1  and consequently the threaded thrust plate  8 , causing the drum to travel axially back towards its starting position as cord  2  is wound onto path  204  of the drum. In operation, a tool such as a hairdryer is attached to the end of cord  2 , optionally using connector  3 . As mentioned hereinabove, depending upon the weight of the tool and/or the user&#39;s preference for the amount of resistance provided by the system, spring  4  may be adjusted by rotating spring tension adjuster  15  about axis a. Optionally, such adjustment may be made using motor assembly  216 . 
     In this embodiment, the drum, thrust plate, and slip rings are nominally the only moving parts, and the (axial) length of the spring remains constant. This helps to prevent the spring from cocking and jamming as a spring of this type may have a tendency to do, if it were wound (or unwound) and stretched axially at the same time. In addition, as also discussed hereinabove, the pitch of helical path  204  and threads of shaft portion  6  may be matched, so that the entry/exit point  206  is axially stationary. This also helps to prevents the cord from jamming or binding. 
     As mentioned hereinabove, various aspects of this embodiment have been provided to minimize the amount of drag (e.g., friction and inertia) in system  200 , to reduce such drag to below 0.5 lbs (0.2 kg), and in particular embodiments, as low as 3 ounces (0.08 kg), i.e., a level of force that is virtually imperceptible to most users, to enable its successful use with relatively lightweight tools  208 , for example, those weighing less than about 25 lbs (11.4 kg), and in particular embodiments, those weighing between about 1-5 lbs (0.4-2.3 kg). 
     The friction of parts moving on the threaded shaft portion  6  is minimized by providing this shaft portion with rolled, rather than machined, threads. These rolled threads offer significantly less resistance than conventional machined threads since the sharp edges and microscopic machining burrs common to such conventional threads are substantially eliminated. In addition the rolled threads and/or the threads of thrust plate  8  may be coated with PTFE, e.g., TEFLON® or other suitable self-lubricating materials to further reduce their friction. Sliding components, such as cutouts  9 A and sleeve  9 B, may also be fabricated from self-lubricating, or otherwise lubricious or low friction materials such as DELRIN® (Dupont Corporation). Moreover, the moving components are preferably fabricated from relatively lightweight and structurally rigid materials, such as molded ABS. This advantageously reduces the inertial mass of the moving parts. Additional, optional functionality may be added to the present invention by adding a torque-adjusting motor assembly  216  to facilitate adjusting the resistance of spring  4  remotely, as discussed hereinabove. Controls for such an assembly  216  may be disposed on the suspended tool or on connector  3 . In addition, a stow-away motor assembly  218 , including a conventional gear train, may be coupled to shaft portions  6  or  6 A, to raise and lower the tool remotely, for example in the event system  200  is installed on a high ceiling. 
     Moreover, in the embodiment shown, the threads are oriented so that extending (unwinding) cord  2  moves the drum axially towards unthreaded shaft portion  6 A. However, the threads orientation (and the drum itself) may be reversed, so that the drum moves in the opposite axial direction during unwinding, without departing from the spirit and scope of the present invention. 
     Turning now to FIGS. 3-4, an alternate embodiment of the present invention is shown as system  200 ′. System  200 ′ is in many respects similar or identical to system  200  described hereinabove, having distinctions which are discussed hereinbelow. In this embodiment, the main shaft, including portions  6 ,  6 A, is supported by opposite ends of a support frame (e.g., bracket)  10 , which includes an opening  20  disposed to align with entry/exit point  206  (FIG.  1 ). Although bracket  10  and opening  20  are shown with respect to system  200 ′, the skilled artisan should recognize that these components, as well as one or more others shown and described with respect to this embodiment  200 ′, may be interchangeably used with other embodiments, such as system  200 , without departing from the spirit and scope of the present invention. The skilled artisan will recognize that use of bracket  10  advantageously enables the system  200 ,  200 ′, etc., to be conveniently mounted, e.g., to a ceiling above a user&#39;s workstation. 
     One difference between system  200 ′ and system  200  described hereinabove, is that rather than using a torque converter  9 , in system  200 ′ spring  4  is coupled directly to drum  1 A. Thus, in this embodiment, spring  4  moves axially as drum  1 A rotates. As shown, the threads of drum  1 A and shaft portion  6  are oriented so that extension (unwinding) of cord  2  causes drum  1 A to move axially towards mandrel  5 , and retraction of the cord  2  causes the drum  1 A to move outward away from the mandrel  5 . Such a thread orientation advantageously compresses spring  4  axially as it is wound. Although such thread orientation may be reversed, such as in the manner discussed hereinabove with respect to system  200 , such orientation would tend to axially stretch the spring as it is wound, which may be undesirable in some applications. 
     As also shown, an alternate slip ring assembly  11 ′ may be used, being coupled to either (axial) end of the drum  1 A. Slip ring assembly  11 ′ includes an inner assembly  11 B and an outer assembly  11 A. The inner slip ring assembly  11 B supports conventional slip (contact) rings  11 G and is rigidly coupled to the drum  1 A. The outer assembly  11 A includes conventional brushes  14  configured to electrically engage rings  11 G when assemblies  11 A and  11 B are rotationally coupled to one another in concentric, interfitting engagement as shown in FIGS. 3 and 4. Inner assembly  11 B including slip rings  11 G, rotates with the drum  1 A, while outer assembly  11 A the other portion containing the brushes  1 A does not rotate. Assembly  11 A may be kept from rotating by any suitable means, such as a notch or detent (not shown) configured to seat or otherwise engage assembly  11 A with an non-rotating component, such as bar  56 . Any suitable bearings, such as self-lubricating bearing material (e.g., TEFLON®) or ball bearings  59 , may be used to effect the rotatable engagement of assemblies  11 A,  11 B, with one another. Electricity may be supplied to the brushes  14  of outer assembly  11 A by wires  21  extending from electrical fixture box  13 . 
     Various additional embodiments may include modifications and alternatives to the teachings of systems  200 ,  200 ′, described hereinabove. Turning now to FIGS. 5-11, system  200 ″,  200 ′″ may be provided, which utilize alternative cord winding approaches including cord tracking mechanisms in combination with an axially stationary (rather than axially movable) drum  1 A′. Such mechanisms may be gear-driven (FIGS. 5-8) or may be belt-and-pulley-driven (FIGS.  9 - 11 ). In both of these configurations, an unthreaded shaft  6 A′ is used. A threaded tracking screw shaft  39  is disposed (e.g., by a suitable gear train including gears  34  and  36  (FIGS.  5 - 8 ), or by a belt  42  and pulleys  40 ,  41  (FIGS.  9 - 11 )) to axially move a tracking arm  38  during drum rotation. As best shown in FIG. 8, tracking arm  38  includes an opening  220  through which cord  2  extends, and which moves axially in tandem with entry/exit point  206 ′ during drum rotation, to guide the cord as it winds and unwinds from helical path  204 A. This guiding action of opening  220  helps to minimize any tendency of the cord to bind or wind over itself on drum  1 A′. 
     As best shown in FIG. 7, in both the gear driven and pulley driven embodiments, a pair of conventional retainer clips  80  may be used to maintain drum  1 A′ in an axially stationary position. Suitable low resistance bearings  7  may be provided to allow the drum to freely rotate about the shaft  6 A′. The mandrel  5  is held centered along its entire longitudinal length, as one end fits into a circular channel in the spring tension adjuster  15 . Although drum  1 A′ rotates freely, mandrel  5  is not intended to rotate, but need not be secured in any fashion that prevents it from rotating. The retainer clip  80  disposed between drum  1 A′ and mandrel  5  acts as a spacer, to prevent any friction-generating contact between the drum  1 A′ and the end of the mandrel  5  as the drum rotates. 
     Turning back to FIGS. 5-8, during operation of the gear-driven tracking mechanism, as the cord  2  is wound on the drum  1 A′, the main tracking gear  34  drives the secondary tracking gear  36 , which rotates screw shaft  39  about its longitudinal axis. This rotation moves tracking arm  38  axially. The diameters of gears  34 ,  36 , and the pitch of the threads of shaft  39  are configured so that the tracking arm  38  moves axially at the same rate (and direction) as entry/exit point  206 ′ during drum rotation, so that the cord  2 , which passes through aperture  220 , is properly guided during winding and unwinding, as discussed hereinabove. The skilled artisan will recognize that the belt-and-pulley-driven tracking mechanism, shown in FIGS. 9-11, is substantially similar to the gear-driven approach, but instead of gears  34  and  36 , uses a main tracking pulley  40 , secondary tracking pulley  41 , and tracking belt  42 . 
     As a further option, any of the various embodiments disclosed herein may be provided with a stop  17 , such as shown in FIG.  5 . The stop acts to prevent further retraction of cord  2  past a predetermined position, to define a ‘home’ position. As a yet further option, stop  17  may be magnetic, to magnetically engage a portion of frame  10  proximate the entry/exit position. Use of a magnetic stop  17  advantageously enables the use of relatively little upward bias (e.g., in the event the user desires little, if any, compensating force) while still holding the device  208  securely in a home position. The stop  17  is adjustable, so it can be positioned nominally anywhere along the cord, thus allowing the object to hang securely at any of various elevations when in its ‘home’ position. A switch  222  (FIG.  2 ), such as a conventional magnetically actuated switch, may also be provided to automatically turn on or cut off power to the device  208  when leaving or returning to the home position, respectively. The skilled artisan will also recognize that power to the device may alternately, or additionally, be controlled manually, such as by a switch located on device  208 , on coupling  3  as discussed herein, and/or by any conventional remote control (not shown). 
     Turning now to FIGS. 12A-12G, additional optional drums suitable for use with any of the embodiments discussed hereinabove are shown. Although these Figures depict several optional drum configurations, they are not exhaustive. The skilled artisan will therefore recognize that drums of virtually any configuration, which are adapted for rotating about a central axis, to wind and unwind a cord thereon, may be provided without departing from the spirit and scope of the present invention. The drum designs selected for a particular implementation of the system  200 ,  200 ′, etc., depends on choices such as the desired action of the object attached to the cord, whether it is desired for the drum to move axially as it rotates, and if not, whether use of a tracking mechanism is desired. For clarity, the drum variations shown in these FIGS. 12A-12G are oriented so the proximal end of the cord engages path  204  on the right hand side of each drum, and, in the event path  204  is helical, winding progresses towards the left hand side of the drum. 
     Moreover, although the path  204 ,  204 A has been described hereinabove as being helical, as will be evident in light of the following, embodiments may be provided in which the path is not helical, but rather, the cord is permitted to wind upon itself, such as shown in FIGS. 12F and 12G. The skilled artisan should recognize that such non-helical paths remain within the spirit and scope of the present invention. 
     Turning to FIG. 12A, drum  1 A, as discussed hereinabove, includes a helical path  204 A in the form of a channel having a progressive radius, configured to receive cord  2  therein. This drum may be axially stationary (e.g., configured as drum  1 A′, discussed hereinabove), in which a tracking arm  38  may be used to guide cord  2  during winding/unwinding. Alternatively, drum  1 A may be configured to move axially during rotation in order to provide an axially stationary entry/exit point  206  as also described hereinabove. The skilled artisan should recognize that all the drums shown and described herein, may be configured for being either axially movable, or axially stationary, without departing from the spirit and scope of the present invention. 
     Drum  1 B has a helical path  204 B defined by channels disposed within a cylindrical surface, which as such, are disposed at a uniform radius along the length of the drum. As such, this drum  1 B does not provide for increasing torque as the cord  2  is extended and the spring wound against its bias. 
     Drum  1 C is similar to drum  1 B with the exception that path  204 C includes a reduced radius portion at one end thereof, to provide the tool with an upward bias when the cord is fully wound, as discussed hereinabove. 
     Drum  1 D has a frusto-conical helical path  204 D, which is similar to path  204  of FIGS. 1 and 2, but is not defined by a channel. 
     Drum  1 E is nominally identical to drum  1 D, though having a cylindrical, rather than frusto-conical outer surface. 
     Drum  1 F is configured so that cord  2  coils on top of itself to decrease the diameter as the cord  2  is unwound. 
     Drum  1 G is similar to drum  1 F, but uses a V-shaped exterior surface to reduce the rate of change of the effective radius as the cord winds and unwinds. 
     Although the foregoing embodiments have been shown and described using conventional torsion coil springs, the skilled artisan should recognize that substantially any type of biasing devices may be used, including other types of springs such as constant tension springs, clock springs, cantilevered springs, pneumatic devices, and the like, without departing from the spirit and scope of the present invention. 
     The following illustrative example is intended to demonstrate certain aspects of the present invention. It is to be understood that this example should not be construed as limiting. 
     EXAMPLE 
     A support assembly  200 ′, substantially as shown and described in FIGS. 3-4 was fabricated, having the following parameters configured to weightlessly support an object weighing in a range of 1-3 pounds. This assembly was built according to the wing parameters: 
     
       
         
               
             
           
               
                   
               
             
             
               
                 Adjuster 
               
               
                 Fiber reinforced ABS plastic using a spur gear with a 20° pressure angle. 
               
               
                 Mandrel 
               
               
                 Thin wall (.08″) ABS plastic. 2.5″ O.D. × 8.5″ long 
               
               
                 Spring 
               
               
                 0.08″ music wire with 80 Teflon-coated coils with a coil diameter of 3.5″ 
               
               
                 Torque converter 
               
               
                 Delrin ® with 8 transfer grooves 9A and a 4.55″ O.D. 
               
               
                 Drum 
               
               
                 ABS plastic with 0.4″ diameter channel 204. The channel had a .5″ lead 
               
               
                 (i.e., pitch, corresponding to .5″ axial travel per rotation) and a 
               
               
                 10° conical taper with a starting helical coil diameter of 5″. Starting 
               
               
                 O.D. 5.7″, starting I.D. 4.8″. Ending O.D. 6.76″, ending I.D. 5.86″. 
               
               
                 Length is 3″ 
               
               
                 Thrust plate 
               
               
                 Delrin ®, with threads to accept threaded rod. 
               
               
                 Threaded Rod (Lead screw) 
               
               
                 Teflon ® coated 303 stainless steel. Rolled threads have a .5″ lead and 5 
               
               
                 starts. 
               
               
                 Conventional Slip-ring assembly capable of handling 15 to 20 amps. 
               
               
                   
               
             
          
         
       
     
     This assembly was found to be capable of successfully supporting objects  208  within a range of 0.6 ounces to 4 lbs. It was also adjusted and successfully tested with a hairdryer weighing approximately 2 pounds, and found to have a ‘drag’ of 3 ounces (0.08 kg) or less. 
     In the preceding specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.