Abstract:
Provided is a lifting system. The lifting system consists of pulleys mounted to moveable, perpendicular shafts that allow the pulleys to be adjustably positioned in horizontal plane. In this way the pulleys can be properly positioned to lift a variety of loads. The system may be powered either manually or by a motor. Further provided is a lifting system, comprising a track and a lifting carriage movable along said track, said lifting carriage including a pulley, a drive shaft for turning said pulley, a support shaft, and a slide assembly connecting said drive shaft to said support shaft, wherein said slide assembly is movable along said drive shaft and the support shaft.

Description:
STATEMENT OF RELATED APPLICATIONS 
   This application claims the benefit of provisional patent application Ser. No. 60/536,747 filed Jan. 15, 2004, incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This application relates generally to an adjustable winch and pulley system. 
   More specifically, this application relates to a winch and pulley system designed to be installed in a fixed location, for example, within a building, or on a mobile device, for example, on a truck bed. 
   BACKGROUND OF THE INVENTION 
   The need exists for an inexpensive, easy-to-use winch and pulley system to facilitate the lifting and moving of heavy objects by a single individual, and which may be adopted to a variety of installations. Crane or hoist systems currently used in buildings are generally not adaptable for use in vehicles or trailers. Gantry cranes require hard, level surfaces and are not suitable for use in a vehicle. Girder cranes also require a building&#39;s structure and cannot be adapted for vehicle use. Furthermore, these systems are often expensive to install. 
   A winch and pulley system installable on a vehicle or trailer would obviate the need to accommodate the use of heavy tow motors. For example, the floor structure of current semi tractor-trailers must be designed to withstand loading by tow motors. This need would be eliminated if the trailer contained its own hoist system. Also, tow motor use would be reduced, adding safety to the workplace. A truck having a self-contained winch and pulley system could allow a single driver to pick-up and deliver heavier packages than is currently possible. Also, the system could be used to secure loads during transport. 
   SUMMARY OF THE INVENTION 
   Provided is a lifting system, comprising a track and a lifting carriage movable along said track, said lifting carriage including a pulley, a drive shaft for turning said pulley, a support shaft, and a slide assembly connecting said drive shaft to said support shaft, wherein said slide assembly is movable along said drive shaft and the support shaft. 
   Further provided is a lifting system, comprising a drive shaft, a support shaft, a first spacing shaft, a second spacing shaft, a first slide assembly for connecting said support shaft to said first spacing shaft and which is positionable along said first spacing shaft, a second slide assembly for connecting said support shaft to said second spacing shaft and which is positionable along said second spacing shaft, a third slide assembly for connecting said drive shaft to said second spacing shaft and which is positionable along said second spacing shaft, a fourth slide assembly for connecting said drive shaft to said first spacing shaft and which is positionable along said first spacing shaft, a driven pulley positionable along said drive shaft wherein said drive shaft causes said driven pulley to rotate, a support pulley positionable along said support shaft, and a windable support which extends between said driven pulley and said support pulley. 
   Further provided is a lifting system mounted on a vehicle, comprising a first track movable from a stowed position to a deployed position on the vehicle, a second track movable from a stowed position to a deployed position on the vehicle, and a lifting carriage movable along said first track and said second track, said lifting carriage including a support shaft and a slide assembly. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of an adjustable winch and pulley system; 
       FIG. 2  is a side section view of the system shown in  FIG. 1 ; 
       FIG. 3  is an end section view of the system shown in  FIG. 1 ; 
       FIG. 4  is a section view of an inner piece of a pulley wheel that would be located on the drive shaft of the winch and pulley system; 
       FIG. 5  is a section view of an outer piece of the pulley wheel that would be located on the drive shaft of the winch and pulley system; 
       FIG. 6  is a section view of the inner and outer pulley pieces that would be located on the drive shaft of the winch and pulley system; 
       FIG. 7  is a section view showing a shroud covering the pulley wheel; 
       FIG. 8  is a left side view of the pulley wheel with shroud shown in  FIG. 7 ; 
       FIG. 9  is a plan view of an alternative embodiment of the adjustable winch and pulley system in which the motor position is fixed; 
       FIG. 10  is an end section view of the system shown in  FIG. 9 ; 
       FIG. 11  is a plan view of an alternative embodiment of the adjustable winch and pulley system utilizing primarily square steel tubing; 
       FIG. 12  is a side section view of the system shown in  FIG. 11 ; 
       FIG. 13  is an end section view of the system shown in  FIG. 11 ; 
       FIG. 14  is a section view of an alternative embodiment of the winch and pulley system that is driven by a hand crank; 
       FIG. 15  is a section view of an alternative embodiment of the winch and pulley system that is driven by the hand crank and has a single slide assembly; 
       FIG. 16  is a section view of an alternative embodiment of the winch and pulley system that is driven by the hand crank with a pair of slide assemblies and coupled to operate in unison; 
       FIG. 17  is a section view of an alternative embodiment having eyebolts instead of winches and pulleys; 
       FIG. 18  is a ratcheting wrench that may be substituted for the hand crank in alternative embodiments; 
       FIG. 19  is a section view of an alternative embodiment of the winch and pulley system installed in the bed of a pickup truck and utilizing modified bed rails and a roll bar to act as a track system; 
       FIG. 20  shows a manually operated boat winch that could provide power to the system shown in  FIG. 19 ; 
       FIG. 21  is a plan view of the system shown in  FIG. 19 ; 
       FIG. 22  is a section view of the system shown in  FIG. 21 ; 
       FIG. 23  is a side view of  FIG. 19 ; 
       FIG. 24  is a section view showing single or multiple cables run from a vehicle bed-mounted winching system, placed directly over pulleys on the lifting carriage; 
       FIG. 25  is a section view showing single or multiple cables from a vehicle bed-mounted winching system pre-wound on a drum and hand crank or ratcheting tools for powering the winching apparatus and pre-winding the drum; 
       FIG. 26  is a section view showing a bed-mounted winching system used with an attached device to supply a frontward pull to the vehicle; 
       FIG. 27  is a section view showing a small truck being used to move an object that is taller than the lifting tracks on the truck; 
       FIG. 28  is a section view showing a small truck loading or unloading on a loading dock; 
       FIG. 29  is a section view showing the small truck with an extended lifting track being used to move a large object; 
       FIG. 30  is a section view showing the small truck unloading cargo to a lower elevation; 
       FIG. 31  is a section view showing a cargo van with an extendable track installed for use with a winch and pulley system; 
       FIG. 32  is a section view of a utility vehicle with an extendable track installed for use with the winch and pulley system; 
       FIG. 33  is an end view of the vehicle shown in  FIG. 32 ; 
       FIG. 34  is an overhead plan view of the vehicle in  FIG. 32 ; 
       FIG. 35  shows an alternative method of track extension; 
       FIG. 36  shows two semi tractor-trailers, back-to-back, with interconnected tracks; 
       FIG. 37  shows a semi tractor-trailer with an extended track system; 
       FIG. 38  shows a vehicle delivering a replacement engine and transmission to a second vehicle via the winch and pulley system attached to canvas supporting ribs; and 
       FIG. 39  shows the winch and pulley system mounted to a vehicle and supporting a tent. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An adjustable lifting system is described herein. The system is comprised of a lifting carriage which is moveable or positionable along one or more tracks. The system may be installed in a building or on a mobile device such as a truck or trailer. 
   The lifting carriage is adjustable so that loads of various sizes may be handled by the system. The lifting carriage is comprised of shafts and slide assemblies. By adjusting the relative spacing of the shafts through the use of the slide assemblies, various sized loads may be raised and lowered. The system could be installed on a vehicle to facilitate the handling of cargo. 
   To lift a load, a user would move the lifting carriage along the tracks to a desired position for lifting. The lifting carriage could either be moved manually or by motor. The user could then adjust the size of the lifting carriage, in order to accommodate the load, by sliding the various shafts along or through the slide assemblies. When the lifting carriage is suitably sized, the user could then lower supports from the lifting carriage, which would be used to raise the load. The supports, for example, could be attached to the load directly or to a platform on which the load sits. 
   To raise the load, the user would activate a drive means, for example, a motor or manually powered winch, which would wind the supports and lift the load. Once raised, the user could then move the load laterally by causing the lifting carriage to move along the tracks. The user could then lower the load to a desired location. If the winch and pulley system were installed on a truck or other vehicle, the user could use the system to load or unload cargo from the vehicle. Track extensions could be deployed by the user to extend the length of the tracks, should the user wish to extend the range of movement available to the lifting carriage. 
     FIGS. 1 ,  2  and  3  represent a current embodiment of the adjustable lifting system, for example an adjustable winch and pulley system. The lifting system is designed to move on a first wheel  61 , a second wheel  62 , a third wheel  63 , and a fourth wheel  64  along the track or tracks. The track, for example, could be comprised of a channel or a rail. Accordingly, the system is positionable along the tracks. 
   A first support shaft  11 , a second support shaft  12 , a third support shaft  13 , and a drive shaft  14  support a first pulley wheel  21 , a second pulley wheel  22 , a third pulley wheel  23 , and a fourth pulley wheel  24 . The support shafts  11 ,  12 ,  13  and drive shaft  14  are adjustable in the horizontal plane for the purpose of positioning the four pulley wheels  21 ,  22 ,  23 ,  24 . The drive shaft  14  is powered by a winch motor  17  and drives two pulleys  23 ,  24 . 
   A first slide assembly  31  couples the first support shaft  11  to the second support shaft  12 . A second slide assembly  32  couples the second support shaft  12  to the third support shaft  13 . A third slide assembly  33  couples the third support shaft  13  to the drive shaft  14 . A fourth slide assembly  34  couples the drive shaft  14  to the first support shaft  11 . The slide assemblies  31 ,  32 ,  33 ,  34  can be constructed as two hollow tubes placed over and at right angles to each other. This results in opposite support shafts, for example the second support shaft  12  and the drive shaft  14 , being located in substantially the same horizontal plane. The tubes may include optional internal bearings to allow for easier movement of the support shafts  11 ,  12 ,  13 , and the drive shaft  14 . 
   The first slide assembly  31  has a first slide lock  41  and a second slide lock  51 . The second slide assembly  32  has a third slide lock  42  and a fourth slide lock  52 . The third slide assembly  33  has a fifth slide lock  43  and a sixth slide lock  53 . The fourth slide assembly  34  has a seventh slide lock  44  and an eighth slide lock  54 . The slide locks  41 ,  42 ,  43 ,  44 ,  51 ,  52 ,  53 ,  54  prevent movement of the support shafts  11 ,  12 ,  13  and the drive shaft  14  through the slide assemblies  31 ,  32 ,  33 ,  34  and are designed to allow the shafts  11 ,  12 ,  13 ,  14  and slide assemblies  31 ,  32 ,  33 ,  34  to be positioned and repositioned to lift loads of various sizes. For example, the slide locks  41 ,  42 ,  43 ,  44 ,  51 ,  52 ,  53 ,  54  could be formed of L-shaped pieces of steel rod with threaded ends which can be fastened to the slide assemblies  31 ,  32 ,  33 ,  34 , for example, screwed into tapped holes on the slide assemblies  31 ,  32 ,  33 ,  34 . Alternatively, the slide locks  41 ,  42 ,  43 ,  44 ,  51 ,  52 ,  53 ,  54  could be comprised of clamps, locking pins, locking tabs, or other locking devices as may exist in the art. 
   The first slide lock  41  and seventh slide lock  44  engage the first support shaft  11 . The second slide lock  51  and fourth slide lock  52  engage the second support shaft  12 . The third slide lock  42  and fifth slide lock  43  engage the third support shaft  13 . The sixth slide lock  53  and eighth slide lock  54  engage a locking rod  18 . By tightening the slide locks  41 ,  42 ,  43 ,  44 ,  51 ,  52 ,  53 ,  54 , the position of the pulley wheels  21 ,  22 ,  23 ,  24  and slide assemblies  31 ,  32 ,  33 ,  34  may be fixed. 
   A first winching cable  15  engages the first pulley wheel  21  and fourth pulley wheel  24  for raising and lowering loads when the winching motor  17  is energized. Similarly, a second winching cable  16  engages the second pulley wheel  22  and third pulley wheel  23 . In addition to using cables, other support devices capable of being wound, that is, windable supports, could be utilized. For example, windable supports could include ropes, braided materials, chains, unstranded wires, flexible synthetic materials, cables, and the like. 
     FIGS. 4 ,  5 , and  6  show components of the pulley wheels  23 ,  24 . Each has an inner core  101  that engages the drive shaft  14  and an outer wheel  102  that surrounds the inner core and engages the winching cables  15 ,  16 . This configuration allows the outer wheel  102  to be removed from the inner core  101  for manual rotation to adjust the length of the winching cables  15 ,  16 . The cable length of each pulley wheel  21 ,  22 ,  23 ,  24  may be adjusted independently of each other without rotating the drive shaft  14 . 
   The first pulley wheel  21  and second pulley wheel  22  may be attached to the first slide assembly  31  and second slide assembly  32 , respectively, by a mechanical means such as screw, bolt, rivet, or clamp, for example. Additionally, they may be secured by a more permanent means such as welding, brazing, or gluing, for example. In an alternative embodiment, the first pulley wheel  21  and second pulley wheel  22  may be connected to their slide assemblies via brackets. 
     FIGS. 7 and 8  show a pulley wheel shroud  111 . The third pulley wheel  23  and fourth pulley wheel  24  are both driven by the drive shaft  14  and may include the pulley wheel shroud  111 . Its purpose is to prevent the winching cables  15 ,  16  from slipping off of their corresponding pulleys. As can be seen in  FIG. 7 , the rim of the pulley wheel shroud  111  is situated to hang over the inner core  101 , which keeps the third pulley wheel  23  adjacent to the third slide assembly  33  and fourth pulley  24  adjacent to the fourth slide assembly  34  during operation and adjustment. The pulley wheel shroud  111  preferably quick-connects to and from its operating position, for example, through the use of a press-release tab or a twist-lock mechanism. 
   The first pulley wheel  21  and second pulley wheel  22  may or may not have internal bearings. They may be mounted as an integral part of their corresponding slide assembly, or they may free float in a manner similar to the third pulley wheel  23  and fourth pulley wheel  24 . 
     FIGS. 9 and 10  show a further embodiment of the adjustable winch and pulley system. A first pulley wheel  121  and a second pulley wheel  122  are supported by a support shaft  114 . The first and second pulley wheels  121 ,  122  are non-driven support pulleys. A third pulley wheel  123  and a fourth pulley wheel  124  are supported by a drive shaft  115  and are driven pulleys. The first and second pulley wheels  121 ,  122  slide and lock on the support shaft  114 , while the third and fourth pulley wheels  123 ,  124  slide and lock on the drive shaft  115 . A first spacing shaft  116  and a second spacing shaft  117  allow for adjustment of the relative positions of the support shaft  114  and the drive shaft  115 . A first slide assembly  131  couples the support shaft  114  to the first spacing shaft  116 . A second slide assembly  132  couples the support shaft  114  to the second spacing shaft  117 . A third slide assembly  133  couples the drive shaft  115  to the second spacing shaft  117 . A fourth slide assembly  134  couples the drive shaft  115  to the first spacing shaft  116 . 
   In this embodiment, the slide assemblies  131 ,  132 ,  133 ,  134  remain in a fixed position adjacent to the wheels of the lifting carriage. Also, the winching motor  118  remains in a fixed position, allowing for the addition of a gearbox, if desired. A gearbox could allow for powered movement of the lifting carriage. 
     FIGS. 11 ,  12 , and  13  show a further embodiment of the winch and pulley system. A first support shaft  201 , a second support shaft  202 , and a third support shaft  203  are comprised of square steel tubing. Likewise, a first slide assembly  211  and a second slide assembly  212  are comprised of square steel tubing. The first slide assembly  211  couples the first support shaft  201  to the second support shaft  202 . The second slide assembly  212  couples the second support shaft to the third support shaft  203 . A third slide assembly  213  couples the third support shaft  203  to a drive shaft  204 . A fourth slide assembly  214  couples the first support shaft  201  to the drive shaft  204 . The third and fourth slide assemblies  213 ,  214 , which house the drive shaft  204 , could include bearings. However, bearings may excluded from the first and second slide assemblies  211 ,  212 . 
     FIGS. 14 ,  15 ,  16  and  18  show a manually operated embodiment of the winch and pulley system. A hand crank  302  or a ratcheting wrench  303 , for example, a ⅜ or ½ inch ratcheting wrench, is inserted into a gearbox  301  and turned by hand to drive the system. The gearbox  301  may be considered to be similar to those used to raise and lower spare tires on vehicles as may exist in the art. For a system with a single gearbox, shown in  FIG. 14 , the gearbox may be used to drive one or a plurality of pulleys.  FIG. 15  shows a single pulley system with a single hand cranked gearbox  304 .  FIG. 16  shows a two-pulley system that includes two gearboxes. A shaft  305  connects the two driving gearboxes for simultaneous operation. Alternatively, the shaft  305 , could be eliminated, and the gearboxes driven independently. In addition to a hand crank  302  or a ratcheting wrench  303 , an electric drill, such as a cordless drill, for example, could be inserted into the gearbox  301  and operated to drive the system, or a fixed motor could be coupled to the gearbox  301  to drive the system. 
     FIG. 17  shows a system in which the driven pulleys have been replaced with eyebolts  311 ,  312 . A support shaft  313  supports a first slide assembly  314  and a second slide assembly  315 . A first eyebolt  311  extends from the first slide assembly  314 . A second eyebolt  312  extends from the second slide assembly  315 . Come along winches, ratcheting winches, or separate pulleys, for example, may be attached to the eyebolts to hoist objects. 
     FIGS. 19 through 25  show an embodiment of the winch and pulley system installed in the bed of a pickup truck having a roll bar  351 , a first bed rail  352  on the driver&#39;s side of the bed and a second bed rail  353  on the passenger&#39;s side of the bed. The winch and pulley system could be installed on a vehicle having a bed or not having a bed or on a trailer. The roll bar  351  and bed rails  352 ,  353  are modified to act as a track system for the winch and pulley system. The first bed rail  352  and second bed rail  353  are vertically adjustable from a storage position P 1  to an operating position P 2 . Both bed rails  352 ,  353  have T-nuts  354 ,  355  attached to them that slide through slots in the roll bar  351  as the bed rails are raised and lowered, keeping the bed rails sturdy and in proper alignment for lifting. 
   The lifting carriage  356  pictured at the top of the raised bed rails  352 ,  353  may be considered to be either moving into a position for lifting or to be moving into a position for storage. When in storage, the lifting carriage may be placed at least partially in a storage unit, for example, a storage box  357 , which may be mounted to the bed of the truck. A first shaft  358  of the lifting carriage  356  and a second shaft  359  of the lifting carriage  356  are stored in a substantially vertical position with one end in the storage box  357  and the other end inserted into slots  360 ,  361  in the roll bar  351 . Because of the ease of assembly and disassembly of the winch and pulley system, it is not necessary to store the first shaft  358  and second shaft  359  of the lifting carriage  356  in a substantially vertical position. Furthermore, the storage box  357  may be of a size that accommodates all components of the winch and pulley system with additional spare room for accessories such as chains, straps, or harnesses, for example. 
   A winch motor  363  may be located on the lifting carriage  356 . Alternatively, a hand-cranked gearbox may be used instead of the winch motor  363 . The gearbox may be driven by a hand crank  302  or a ratcheting wrench  303 . In addition to the hand crank  302  or the ratcheting wrench  303 , an electric drill, such as a cordless drill, for example, could be inserted into the gearbox and operated to drive the system. 
   Still alternatively, the gearbox or winch motor  363  may be located in the storage box  357 . A cable or cables  362  are shown in use at a first angle A 1  or, alternatively, at as second angle A 2 . When used at the first angle A 1 , the cable or cables  362  can be used to pull loads in a primarily horizontal direction or up a ramp, for example. When used at the second angle A 2 , the cable or cables  362  can be used to lift items vertically by placing them over pulley wheels on the lifting carriage  356  or pre-rolling them onto a cable drum  374  situated on the lifting carriage  356 . A manually operated boat winch  321  for example, as shown in  FIG. 20 , located in the storage box  357 , could allow for manual operation of the winch and pulley system. 
   Reinforced bracing  372  may be added to the storage box  357  to allow for pulling a heavy load in the horizontal direction when the winch motor  363  is located on the lifting carriage  356 . A slot  373  may be built into the storage box  357  to facilitate horizontal pulling, whether through a lifting carriage  356  or storage box  357  mounted winching mechanism. Other winching configurations may require other configurations of storage box  357  bracing and winching mechanism mounting. 
     FIG. 24  shows a winch cable  362  or a plurality of winch cables run from a winching mechanism mounted in the bed of a vehicle, for example in the storage box  357 , and placed directly over pulleys on the lifting carriage  356 . Similarly,  FIG. 25  shows a winch cable  362  or a plurality of winch cables run from a bed-mounted winch. However, in this configuration, the winch cable  362  is pre-wound onto a cable drum  374 . When the winch cable  362  is initially attached to the drum  374 , additional windable load supports  375  are in position P 11 . As the winch cable  362  is wound around the drum, the additional windable load supports  375  are lowered to position P 12 . 
     FIG. 25  also shows a ratcheting wrench  303  and a hand crank  302  that may be used to power a manually operated truck-mounted winch and pulley system. In addition to a hand crank  302  or a ratcheting wrench  303 , an electric drill, such as a cordless drill, for example, could be inserted into the gear box and operated to drive the system. 
   A bed mounted winch and pulley system may be used with an attached device  401  to supply a forward pull to the vehicle, as shown in  FIG. 26 . Additionally, a winching motor located in the front of the vehicle may be used to drive the winch and pulley system located in the bed of the truck. 
   Objects taller than the lifting tracks  413  may still be moved, as shown in  FIG. 27 . One support shaft  411  is removed so that an object  412  to be lifted may be positioned between the lifting tracks  413 . When the removed support shaft  411  is replaced, the lifting carriage surrounds the object  412  to be lifted. Lifting objects taller than the lifting tracks  413  may be accomplished through the use of a four-pulley system or through the use of two single-shaft lifting units. In addition to lifting objects taller than the lifting tracks  413 , objects may be lifted onto or off from a loading dock  414  as shows in  FIG. 28 . 
   Extended lifting tracks  415  may be used to lift large objects, as shown in  FIG. 29 . In this example, single-shaft pulley units  418  are being used to lift a piano  420 . Vertical posts  416  support the extended lifting tracks  415 . A jack  417  may be used to support the truck bed to prevent compression of the suspension springs during loading or unloading. 
   The winch and pulley system may be used to lower cargo to an elevation beneath the truck wheels as shown in  FIG. 30 . 
   The winch and pulley system may be installed in a cargo van as shown in  FIG. 31 . In the embodiment shown in this figure, the track extensions  501  may fold out from a vertical storage position P 21  to a horizontal operating position P 22 . When the system is in use, a latch  502  could keep the van&#39;s doors  503 , to which the tracks  501  are attached, in proper alignment. 
   The winch and pulley system may be installed at the rear of a truck as shown in  FIGS. 32 through 34 . In the embodiment shown in these figures, the track extensions  601  fold out from the truck from a vertical storage position P 31  to a horizontal operating position P 32 . 
   A further method of track extension is shown in  FIG. 35 , in which the track extension  701  is stored within the main track  702 . 
   As shown in  FIG. 36 , a first truck  703  having the winch and pulley system could be parked back-to-back with a second truck  704  having a similar system. Their tracks could then be coupled so that a lifting carriage  705  and the cargo it supports can be transferred from the first truck  703  to the second truck  704 . 
   The winch and pulley system could be adapted for use with multiple track extensions  801  and support posts  802  as shown in  FIG. 37 . Additionally, the system could be mounted to the canvas supporting ribs  803  common to military vehicles as shown in  FIG. 38 . 
   A shown in  FIG. 39 , the system may be configured to support a tent  901 . In such a configuration, the tent may be stored in the storage box along with the lifting carriage  902  when not in use, or in a separate storage box dedicated to the tent. When deployed, the lifting carriage  902  could be used to support the top and/or sides of the tent  901 . 
   The mounted winch and pulley system of any of the embodiments described herein could be equipped with servomotors to automatically position the lifting carriage. This would obviate the need to position the lifting carriage by hand. Servomotors responding to a positioning signal could move the lifting carriage in the horizontal plane to a desired location. The positioning signal could be generated by a computer-based control system, such as a personal computer, a programmable logic controller, or other microprocessor-based system, for example. An additional servomotor or servomotors could further control the vertical lifting action of the winch and pulley system. 
   The invention has been described hereinabove using specific examples; however, it will be understood by those skilled in the art that various alternatives may be used and equivalents may be substituted for elements or steps described herein, without deviating from the scope of the invention. Modifications may be necessary to adapt the invention to a particular situation or to particular needs without departing from the scope of the invention. It is intended that the invention not be limited to the particular implementation described herein, but that the claims be given their broadest interpretation to cover all embodiments, literal or equivalent, covered thereby.