Abstract:
A cervical traction assembly whereby the user can exert a variable load on the cervical spine and receive a sensory feedback when the traction is at or within range of a target load. The assembly includes a head harness wrapped around the forehead of the user that is attached to a traction bar connected to a load line assembly that passes through a direction reversal pulley and terminates with force straps actuated by the user&#39;s legs. The load line assembly includes a spring force scale that includes a control assembly that allows the user to set a target applied load and receive sensory feedback in the form of varying audible signals as the user applied load approaches, meets and exceeds a target load range.

Description:
FIELD OF THE INVENTION 
     The present invention relates to devices for applying cervical traction, and, in particular, to a cervical traction device wherein the user selects and applies a loading to the cervical area and receives audible feedback with respect thereto. 
     BACKGROUND OF THE INVENTION 
     Cervical traction devices are used for applying traction to the cervical spine. At a practitioner&#39;s office elaborate and expensive devices are available. While beneficial under the operation of skilled personnel, these units are normally too complex and expensive for home use where it is recognized that therapeutic value is obtained through the regular use in accordance with prescribed protocols. 
     Many such devices have been available and generally rely on static weights applied at a harness wrapped around the user&#39;s head. It is also recognized that the use of intermittent and variable loadings provides additional advantages. One such traction device is disclosed in U.S. Pat. No. 4,407,274 to Goodly wherein a variable loading is applied by foot extension by the user with the loading displayed for viewing and control by the user. While providing versatility in loading, certain deficiencies are apparent. The load is displayed on a spring loaded scale requiring the user to adjust body position for viewing, thereby redirecting user focus from the routine. Further, the load lines can twist the scale during use preventing the user from monitoring the loading. Additionally, the scale load units are tightly spaced, making it is difficult for a user to maintain an observable constant loading. It would accordingly be desirable to provide a home use cervical traction device that would enable the user to undertake verifiable traction protocols without the limitations of the above approaches. 
     SUMMARY OF THE INVENTION 
     The present invention provides cervical traction assembly whereby the user can exert a variable load on the cervical spine and receive a sensory feedback when the traction is at or within range of a target load. The assembly includes a head harness wrapped around the forehead of the user that is attached to a traction bar connected to a load line assembly that passes through a direction reversal pulley and terminates with force straps actuated by the user&#39;s legs. The load line assembly includes a spring force scale that includes a control assembly that allows the user to set a target applied load and receive sensory feedback in the form of varying audible signals as the user applied load approaches, meets and exceeds a target load range. 
     In one aspect, the invention provides a cervical traction device for applying traction to the cervical spine of a user wherein a harness wraps about the head of a user and a pair of strap members is attached at one end to the harness and at the end to an elongated traction bar. A load line is attached at one end to said traction bar and through a load reversal device mounted on a support surface beyond the head of the user that routes load line from said traction bar to position over said user connected with a force and feedback assembly. A force loading member operable by the legs of the user connected to the other end of said force and feedback assembly for applying a force thereto. The force and feedback assembly is operative to provide a sensory output responsive to said force applied by said force loading member. In other aspects, the sensory output is audible; the force and feedback assembly may include a spring member operatively connected between said load line and said force loading member, and the sensory output is responsive to change in spring length from the force; the force and feedback assembly may include a battery power source connected to first circuit means and providing a first output related to said force on said spring, a microprocessor receiving said first output and actuating said sensory device to provide and audible output based on said force; a second circuit means may be connected to the power source and an indicator provided for setting a target load force and providing a second output related to said setting to the microprocessor that compares the first output and the second output and actuates the sensory device to produce an audible output characteristic of said comparing; the output characteristic may be based on an equivalence of said first output and said second output and another output characteristic provided based on a difference in said first output and said second output wherein a first output characteristic is based on said first output exceeding said second output and a second output characteristic is based on a second output exceeding said first output or the output characteristic based on the first output being within a predetermined range of the second output. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become apparent upon reading the following description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective drawing of the cervical traction assembly in use; 
         FIG. 2  is a perspective view of the components of the cervical traction assembly of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of the force scale; 
         FIG. 4  is a side view of the force scale; 
         FIG. 5  is a top view of the force scale; 
         FIG. 6  is a perspective view of the force scale with the case removed; 
         FIG. 7  is a side cross sectional view of the force scale; 
         FIG. 8  is a top view of the force scale with the case removed; 
         FIG. 9  is a schematic drawing of the circuit board for the force scale; and 
         FIG. 10  is a schematic drawing of the controller for the force scale. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , there is shown a cervical traction assembly  10  whereby a user  12  can self apply a variable and quantifiable traction loading to the cervical spine in accordance with a prescribed protocol and receive sensory feedback as the loading approaches, reaches and exceeds a predetermined applied load range. 
     The cervical traction assembly  10  includes a harness  20  wrapped around the forehead of the user  12 , a traction bar  22 , and a load line assembly  23  including a mounting assembly  24 , a load line  26 , a line clamp  28 , a force scale  30 , and force straps  32 . 
     The harness  20  is an elongated strap of a soft flexible material that is wrapped around the forehead of the user  12 . The harness  20  has ends thereof attached by suitable fasteners such as hook and loop fastening systems. The harness  20  includes side straps  34  having distal end loops  36 . The traction bar  22  is generally V-shaped having a pair of diverging side arms  38  integrally joined at an arcuate center section  40  and terminating with reversely turned ends  42 . In assembly, the distal loops  36  are inserted into the ends  42  of the traction bar  22 . The traction bar  22  is formed of a rigid material, such as metal or plastic. A steel rod of circular cross section is used in the present embodiment. 
     The mounting assembly  24  is adapted for mounting on a solid vertical surface. Herein, the mounting assembly  24  is adapted for retention in a door casing between the door and jam at an elective height for proper application of cervical traction force. The mounting assembly  24  includes a mounting strap  44  attached at one end to a suitable line reversing device in the form of a pulley  46  and having an enlarged terminal end  47  inserted behind the door for resisting separation or movement under loading. 
     The load line  26  is flexible line of suitable material such as braided rope. The load line  26  is attached at one end to the center section  40  of the traction bar  22  and extends to and around the pulley  46  with the other free end extending through the line clamp  28 . 
     The line clamp  28  is a commercially available length adjustment device including a clamp body having a socket receiving an annular clamping ferrule through which the free end  48  of the load line  26  extends. The ferrule may be adjustably positioned along the line. Upon application of force the ferrule is compressively seated in the clamp body socket and about the line to maintain position thereon. The line clamp  28  accommodates the variables in user and mounting positions. The clamp body includes a pivotal bracket  52  that is releasably attached to one end of the force scale  30 . 
     The force straps  32  are formed an elongated flexible material and include mounting loops  54  at one end attached to the force scale  30  and foot loops  56  at the other end for receipt of the user&#39;s feet for application of user imparted loading to the assembly for applying cervical traction. The length of the force straps  32  preferably places the force scale  30  at a mid torso position in use. 
     Referring to  FIGS. 3 through 8 , the force scale  30  interconnects the force straps  52  and the load line  26  and allows the use to set a traction load and to receive sensory feedback as the applied load is increased, met or exceeded. The force scale  30  comprises a case assembly internally housing a spring assembly  62  and a load set and feedback assembly  64 . The case assembly includes an extruded aluminum rectangular tubular case  66  having a mount cap  68  at one end and a hook cap  70  at the other end. The mount cap  68  includes a base telescopically inserted into the end of the case and a pair of spaced slots at the head thereof receiving a mount bracket  72 . The mount bracket  72  is provided with a closed hook end  73  and a pair of spaced arms  74  with eyelets. The arms  74  are inserted into slots in the mount cap  68  and secured thereto by a spring pin  75  extending through aligned holes in the mount cap base, the side walls of the case, and the eyelets whereby the mount bracket  72  is pivotally connected to the mount cap  68 . 
     The hook cap  70  has a base inserted into the other end of the case and secured thereto by a spring pin  80  extending through aligned holes in the base and the side walls of the cane. The hook cap  70  includes a cylindrical rear sleeve  82 . An actuator hole extends through the hook cap  70  including the sleeve. 
     The spring assembly  62  includes a coiled compression spring  84 , and actuating arm  86 , and an end guide  88 . A spring retainer  89  is slidably housed in the spring  84  for preventing sagging thereof to thereby avoid with the feedback assembly  64 . The spring  84  has one end inserted over the sleeve  82  in the hook cap  70  and the other end terminating adjacent the mount cap  68 . The actuating arm  86  includes a curved end hook  90  connected to the bracket  52  and a cylindrical actuating shaft  92  extending through the actuator hole of the hook cap  70  and the compression spring  84 . The shaft  92  has a terminal threaded end projecting beyond the end of the spring. The end guide  88  has a cylindrical mounting sleeve  93  received within the end of the spring and a through hole through which the end of the actuating arm projects. The end guide  88  includes a rectangular slide block  94  slidably supported at the inner side walls and base of the case and engaging the end of the spring. A threaded nut  96  is coupled to the threaded end of the shaft  90  and is adjusted to provide an initial preload on the spring. The slide block  94  includes a projecting tip  98  that extends through and rides within a longitudinal slot  100  from in the base wall of the case. The slot  100  includes scaled indicia  102  at the side thereof whereby the position of the tip  98  with respect thereto gives a reading of the operative applied loading on the force scale. The guide block includes a rearwardly projecting flange  104  carrying a double blade spring contact  106  for use in load measurement as described below. 
     The feedback assembly  64  includes a rectangular printed circuit board  110 , a battery unit  112 , a controller  114  and load set slide  116 . The board  110  is telescopically longitudinally inserted into slots  117  ( FIG. 3 ) formed on the interior side walls of the case  66 . The case includes a top longitudinal slot  120  through which the indicating tip  121  of the load set slide projects allowing the slide to be variably position at target traction indicia  122  ( FIG. 5 ) at the side thereof. The battery unit  112  comprises three batteries mounted on the top surface of the board and enclosed by a protective cover. The controller  114  is mounted on the bottom surface of the board  110  and enclosed by a protective cover. The target weight slide  116  includes a double blade spring contact  124  that engages and traverses the board circuitry in setting the target load for the feedback assembly. The spring contact  106  on applied weight slide engages the lower surface of the board and traverses the board circuitry in establishing and denoting the applied load by the user. 
     Referring to  FIG. 9 , the board  110  comprises an array of serially connected resistive circuits  130  connected to the battery unit  112 . On the top surface of the board on the adjust side are a series of contact pads  132  connected to an opposed resistive circuit  130  and a continuous conductive strip  134  is spaced outwardly thereof. In operation, one blade of the contact  124  successively engages the pads  132  and the other blade traverses the strip  134 . On the bottom surface on the applied load side are a similar series of contact pads  140  connected to an opposed circuit at vias, not shown, and a continuous conductive strip  142 . Both surfaces are shown in a common plane for convenience of illustration. In operation, one blade of the applied load contact  106  successively engages the pads  140  and the other blade continuously engages the strip  142 . The target load side is outputted from strip  134  at output  150 . The applied load side is outputted from strip  142  at output  152 . The board thus functions as dual potentiometers producing an output related to position, and correlating to a loading either as set or applied. 
     Referring to  FIG. 10 , the outputs  150 ,  152  are fed to a microcontroller  160 . The microcontroller  160  processes the outputs and provides a signal to a sensory audio device  162 , such as a piezoelectric beeper. 
     The microcontroller)  40  is programmed to compare the outputs and produce a response at the device  162  indicative of the proximity of the applied load to the target load. A suitable microcontroller is an 8-pin Flash-based 8-bit CMOS microcontroller available as product 12F675 from Microchip. In the present embodiment, the microcontroller may provide for a first type response at one level when the applied load is above or below the target load, and a second type or silence when the loads are equal. Different responses may be used to distinguish the above target loads from the below target loads. Further and preferred, a tolerance range is provided for the target load taking into consideration that it is extremely difficult for the user to achieve and maintain an exact loading. Therein, a first frequency is applied when the applied load is less than the lower limit of the target load, the same or a differing frequency when the applied load is greater than the upper limit of the target load, and a still differing response when the range is achieved. In the preferred embodiment a single beep is used for the lower loads, silence for the target range, and a double beep for the higher loads. It will be appreciated that other type of auditory distinction may be used. 
     For use, the assembly is mounted as shown in  FIG. 1  and will vary from user to user and from one session to the next dependent on body position. For all installations it is preferred to mount the pulley at location that will provide a shallow traction angle of about 30° or less, and clearance of the return run to the load scale comfortably above the user&#39;s body. Also it is preferred to adjust the load line  26  at the line clamp  29  to locate the load scale  30  below the torso so that upon release it clears the user&#39;s head. The unloaded position should provide for sufficient flexure of the legs to effect a travel producing the desired applied load within the user&#39;s capability. The user sets the load slide at the target loading and then undertakes the desired protocol for applying traction. As the load increases, the user will receive auditory feedback from the sensory device at a response denoting loading below the target range. As the load increases to the target range, the response will change as programmed. Depending on the protocol, the user may seek to achieve this target range for a set period of time or comfort. The time may be monitored as desired, and could optionally be incorporated into the force scale. During the session, if the load exceeds the target range the user will receive feedback in the form of the indicative auditory response and can lower the loading to return to the target range. During the session, the feed back is supplied passively. At completion, the unit can be readily disassembled and compactly stored awaiting the next session. 
     Having thus described a presently preferred embodiment of the present invention, it will now be appreciated that the objects of the invention have been fully achieved, and it will be understood by those skilled in the art that many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the present invention. The disclosures and description herein are intended to be illustrative and are not in any sense limiting of the invention, which is defined solely in accordance with the following claims.