Abstract:
The present invention is a portable device for administering spinal decompression therapy. The device features a compact size and an innovative tension control mechanism to facilitate, in particular, a therapy for imbibition. The use of fabric for a sling and a platform adds comfort features while reducing weight.

Description:
This is a Non-Provisional Patent Application. 
     FIELD OF THE INVENTION 
     This invention relates to medical traction devices, and particularly to portable spinal decompression mechanisms. 
     BACKGROUND OF THE INVENTION 
     Traction devices for stretching the neck and spine are commonly used in hospitals, physical therapy clinics and other therapeutic venues. Typically, such devices apply a measured amount of force directed to decompress the spine and give relief from back pain caused by injury or degenerative effects. Specifically, they are used to treat disc bulges, disc herniations, facet syndrome, nerve impingement, spinal/foraminal stenosis, degenerative disc disease, osteoarthritis in the spine, muscle spasm, tension headaches, decreased joint space, decreased range of motion and facet joint inflammation. Typically, the apparatus includes some type of sling or harness to cradle the head with pressure applied thereto by means of pulleys and weights, often involving fixtures to a bed or wall. Commonly, assistance from another is needed to setup the gear and monitor its use. 
     In the technology of non-surgical spinal decompression, one therapy of particular utility is that of Imbibition. Imbitition involves the gentle stretching and relaxing of the spine to foster hydration and blood flow to the spinal discs. Such action applied along the cervical spine can create a negative pressure in the center of the intervertebral disc. The negative pressure fosters a suctioning effect, or vacuum phenomenon, which reduces the size of a herniated or bulging disc&#39;s gelatinous internal nucleus pulposus. The technique diminishes, or eliminates, nerve compression, while an osmotic gradient is created thereby helping to bring nutrients and water into the disc. The intervertebral discs have poor circulation and depend upon receiving nutrition by diffusion across the end plates of vertebrae above and below. 
     The “pumping action” created by the stretching and relaxing occurs naturally in the healthy case with daily motions and body positions. In the damaged or degenerative case, however, this gratuitous pumping action may be reduced or lost with disastrous effect to the already-poor circulation. A non-invasive remedial therapy, therefore, is to re-supply the disks with nutrients and blood that help the disks heal from inside out. This type of therapy is preferably practiced on a daily basis; and, therefore, as a matter of practicality, must be free from an institutional setting. Hence, the need arises for portable traction devices that are readily at hand for unassisted use. 
     Portable traction devices are described in U.S. Pat. No. 5,052,378 to Chitwood and U.S. Pat. No. 4,356,816 to Granberg. In both cases, a bed or platform supports a prone patient over a box frame housing a take-up apparatus. The take-up apparatus selectively applies tension to a head harness through an attached boom structure. The large frame members, such as the box, however, do not lend themselves to a compact configuration for storage or travel. It would be hard to imagine the Chitwood or Granberg device used in a hotel room on a trip, for example. 
     U.S. Pat. No. 5,451,202 to Miller discloses an apparatus without the bed which can be disassembled for storage. The storage configuration, nevertheless, made unwieldy by one out-sized frame member, is anything but compact. In addition, Miller teaches an overhead control requiring the patient to lift one or more arms to reach and operate the control. The lifting of an arm, and particularly the upper arm, from its prone position at rest activates the back musculature. Tension in the back muscles is not conducive to the relaxing effect sought in Imbibition Therapy. Further, Miller applies tension through a ratchet mechanism that cannot be incrementally backed off without tripping a release and jarringly withdrawing tension. Preferably, in the case of Imbibition, the tightening and slackening are smoothly applied in incremental measure and without the patient feeling abruptness or discontinuity. 
     There is an unfulfilled need in the state-of-art for an easy-to-assemble traction device which can be reduced to a compact and travel-friendly profile, and which can be operated to apply tension optimally to the spine for Imbibition Therapy and for pain relief. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the shortcomings and gaps in the current art field with novel solutions and improvements. It is, therefore, an object of the present invention to provide a fraction device for personal use which is easy to assemble, lightweight and collapses into compact form. It is a further object to make the head-halter component comfortable for the patient&#39;s head through shaping, material selection and adjustment parameters. It is a further object to provide a tensioning control which is incrementally adjustable in both tightening and slackening and which indexes positions smoothly. It is a further object to use a worm gear for reversible action and position hold. It is a further object to operate the tensioning device while maintaining complete relaxation of the back muscles. It is a further object to provide leverage through gear ratios to make operation of the tensioning control as convenient and effortless as possible. It is a further object to provide an emergency relief button to instantly release traction. It is a further object to provide an automatic force limiter as a safety feature. 
     These objects, and others to become hereinafter apparent, are embodied in a portable device for spinal decompression therapy comprising, in a first part, a support base with two hingeably-attached horizontal members deployed a shoulder-width apart. In another part, a fabric web is stretched between the horizontal members for deployment at least partially beneath the back of a person lying against the fabric web, the body-weighed fabric web anchoring the support base to a level surface. In another part, a vertical structure is hingeably attached to the support base and deployed there upon at a first preferred vertical angle to fixedly position a distal end overhead. In another part, a hammock is suspended from the distal end to cradle the person&#39;s head at a second preferred vertical angle. In a last part, a means is provided for incrementally applying and releasing tension to the hammock, the manipulation of tension alternately stretching and relaxing the person&#39;s cervical spine along the second preferred vertical angle, the means including an automatic release of tension when a preferred critical value is reached. The portable device so configured may be folded and rolled up into a compact profile. 
     In a preferred embodiment, the means for incrementally applying and releasing tension comprises a reversing worm gear actuated by rotating a handle, the worm gear locking progress at each advanced position of the handle. A gear chain is enmeshed with the worm gear, the gearing apparatus designed to achieve mechanical leverage for comfortable hand operation. The gear chain drives a drum which spools an inner steel wire of a Bowden cable, the inner steel wire connected at a distal end thereof to the hammock. 
     As this is not intended to be an exhaustive recitation, other embodiments may be learned from practicing the invention or may otherwise become apparent to those skilled in the art. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood through the accompanying drawings and the following detailed description, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
         FIG. 1  is perspective view of the portable decompression device with a patient in position for its operation; 
         FIG. 2  is a perspective view of the portable decompression device; 
         FIG. 3  is an exploded view of the portable decompression device; 
         FIG. 4  is a perspective view of the frame elements of the device with the support component partially folded; 
         FIG. 5  is a detail view of an articulated hinge showing the toggle locking mechanism; 
         FIG. 6  is a perspective view of the frame elements showing the support component fully folded; 
         FIG. 7  is a perspective view of the fully folded frame; 
         FIG. 8  is a perspective view of the traction control mechanism; 
         FIG. 9  is an elevation view of the traction control mechanism; 
         FIG. 10  is a section view taken along lines  10 - 10  of  FIG. 9 ; 
         FIG. 11  is a plan view of the traction control mechanism; 
         FIG. 12  is a section view taken along lines  12 - 12  of  FIG. 11 ; 
         FIG. 13  is a perspective view of the tension control mechanism with the casing removed to show the gear chassis and button in solid line; 
         FIG. 14  is the view of  FIG. 13  with the gear chassis cover and button removed to show the gear nest and release spring; 
         FIG. 15  is a partial elevation view showing the skeletal spine before stretching; 
         FIG. 16  is a partial elevation view showing the skeletal sine after stretching; and 
         FIG. 17  is a plan view of the contoured occiput collar showing the fingers. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Unless the context clearly requires otherwise, throughout the description and the claims, the term “tension” will be taken to refer to the tension force communicated by the Bowden cable, or equivalent, to the patient; the term “bias” will be taken to refer to the compressive reaction of the spring, or equivalent; and the complex term “gear train” will be taken to refer to the inter-meshed gears between and including the worm-gear follower and the driving gear of the drum, or equivalents. 
       FIGS. 1-3  show the constituent elements of a portable decompression device  1 . A frame  3  supports a hammock  4  to suspend the head of a patient&#39;s body  2  during use of the apparatus. The hammock  4  is manipulated by a means for applying and reversing tension  30 . The frame  3  is comprised of a support base  10  and a vertical structure  20 . The vertical structure  20  is attached through at least one hingeable joint  13  to the support base  10 . The support base  10  is comprised of two horizontal members  11 , which are connected by another iteration of the hingeable joint  13 . When the support base  10  is deployed, the two horizontal members are spaced a shoulder-width apart, referencing the patient&#39;s body  2 . A fabric web  12  spans between the two horizontal members  11  with sleeves  7  on opposing ends thereof jacketing, or otherwise attaching to, each horizontal member  11 . 
     The fabric web  12  serves as a mat beneath the upper torso of the patient body  2  while the patient lies face-up on a level surface  7  (not shown), such as a floor. The fabric web  12  anchors the support base  10 , and, therefore, the structurally-connected fame  3 , to the level surface  7 . The anchor is sufficient to immobilize the frame  3  when tension is applied to the patient&#39;s body  2 . 
     The vertical support  20  may be a tower  26  in one embodiment. In the preferred embodiment, the vertical support  20  is comprised of an A-frame  25 . The A-frame  25  is comprised of two struts  21 . The two struts  21  are connected together at the distal end  24  of the vertical support  20  by at least one iteration of the hingeable joint  13 . The two struts  21  are rotatably connected to the support base  10 , each strut  21  to a corresponding horizontal member  11 , through T-joints  15 . T-joints  15  fix the inclination of the A-frame  25  relative to the level surface  7  according to a first preferred vertical angle  22  ( FIG. 2 ). The first preferred vertical angle  22  sways the structure backwardly and serves to vector the applied tension both horizontally and vertically in a way optimized for the cranial and spinal curvatures. In the preferred embodiment, the first preferred vertical angle  22  is between 60° and 75°. In a particular preferred embodiment, the first preferred vertical angle  22  is nominally 68°. 
     The frame  3  is collapsible, as shown in  FIGS. 4-7 . The hingeable joint  13  is immobilized in its extended position by toggle lock  14 . Toggle lock  14  is comprised of a pawl  16 , which can be toggled by hingeable connection to one part of hingeable joint  13  into and out of a corresponding recess (not shown) in the connecting part of hingeable joint  13 . T-joint  15  is rotatable about a longitudinal axis  17  ( FIG. 3 ) located at each horizontal member  11 . With the articulation of joints here above described, the frame  3  may be folded into a compact configuration, as shown progressively in  FIGS. 4-7 .  FIG. 4  shows the horizontal fold beginning, which is then completed in  FIG. 6  and joined by the vertical fold in  FIG. 7 . When the frame  3  is unfolded and locked in its deployment arrangement, the structure is rendered rigid. 
     The hammock  4  is suspended from the distal end  24  of the vertical structure  20  at a second preferred vertical angle  23  ( FIG. 2 ). The second preferred angle  23  is designed to allow the head to comfortably tilt back from the neck to position the occiput (back of the head) advantageously for the hammock  4  to grip thereupon and stretch the cervical spine.  FIGS. 15 and 16  illustrate this stretching action with a skeleton cartoon. In  FIG. 16 , the vertebrae of the neck are shown in exaggerated extension. While the second preferred angle  23  may be initially set by elastically guying it with stabilizer lines  6  from strategically-placed anchor points on the support base  10 , it may be adjusted for comfort by the patient shifting forward or rearward over the support base  10 . In the preferred embodiment, a spongy occiput collar  5  is used to comfortably cradle the head (FIGS.  3  and  15 - 17 ). The occiput collar  5  has proud fingers  9  to gently grip the head as it partially wraps around the back of the head at the cranial base. In the preferred embodiment, the second preferred vertical angle  23  is between 55° and 65°. In a particular preferred embodiment, the second preferred vertical angle  23  is nominally 60°. 
     The hammock  4  is suspended from the distal end  24  of the vertical structure  20  by the means for applying and reversing tension  30 . The means for applying and reversing tension  30  is comprised of a Bowden cable  36 . Bowden cables are familiar from bicycle technology, where they are used in the actuation of brakes and gears. The Bowden cable  36  is comprised of an outer sheath  39 , which is essentially a flexible conduit fixing a pre-determined running distance between an operating end  54  and a running end  55 , combined with an inner steel wire  37  channeled there within. 
     The spans of frame  3  between joints are bridged with tubular members  8 . Tubular members  8  are fastened to hingeable joints  13  and T-joints  15  by rivets, or by other fastening means known in the art. Select hollow tubular members  8 , combined with apertures through the intermediary joints, provide a passage for the Bowden cable  36  to be threaded from an open end of one of the horizontal members  11  to and through the distal end  24  of the vertical structure  20 . The inner steel wire  37  exits the passage and the outer sheath  39  to connect at its distal end  38  with the hammock  4  and convey thereto a tension force which may be applied remotely at its proximal end  50  ( FIG. 12 ). A turning block, or sheave, may be used at the exit point (not shown) to reduce friction. 
     The means for applying and reversing tension  30  further comprises a tension control mechanism  40 , as best shown in  FIGS. 8-14 . The tension control mechanism  40  is located at the operating end  54  of the Bowden cable  36 , where the pre-determined running distance of the cable positions it anywhere within reach of the patient; and, particularly, where the patient may access it with minimal arm movement. The tension control mechanism  40  may, in one embodiment, be a forward-and-reverse ratchet system. In the preferred embodiment, the tension control mechanism  40  is comprised of a worm gear  32  driven by a dial handle  51  to turn a drum  35  through enmeshment with a gear chain  33 . The drum  35  spools thereon the proximal end  50  of the inner steel wire  37 . The dial handle  51  is essentially circular and may have fluting to facilitate a hand grip. When the dial handle  51  is rotated clockwise, the drum  35  spools-in to tighten tension at the hammock  4  and reverses, spooling-out to loosen tension, by counter-clockwise rotation. 
     In the preferred embodiment, the dial handle  51  has an inside gear  52  which meshes with the worm gear  32  on an offset axis ( FIG. 10 ). The greater the offset, the greater the mechanical leverage applied. The mechanical leverage can be further augmented by a differential enlargement of the dial diameter. The worm gear  32  meshes with a worm gear follower  34  in the gear chain  33  ( FIG. 12 ). A phenomenon of worm gears is that, while the worm gear can easily turn the follower, the follower cannot turn the worm gear. This is because the pitch on the worm is so shallow that, when the follower tries to turn it, the friction between the gears holds the worm in place. As a consequence, rotational positioning can be advanced and held with a worm gear without the interfering geometry common to a ratchet system. The remaining linked gears in the gear chain  33  provide further gear reduction opportunity for driving the drum  35 . By manipulating the gear ratios in the design of the gear chain  33 , a balance can be struck between power and revolution speed. A gear ratio is, mathematically, the ratio of the number of teeth in a driver/driven gear pair. The gear ratio of a compound gear set, such as that of the gear chain  33 , is the multiplication of the ratios of each pairing. Directional correction can be made by inserting an idler gear in the sequencing. The idler gear otherwise has no effect on the ratio. With proper design, the dial will be easy to handle and turn and a full revolution of the drum will amount to only a slight rotation of the dial. 
     In the preferred embodiment, the gear chain  33  is housed in a gear chassis  43 . The gear chassis  43  may be shifted either vertically or horizontally if sufficient excess internal space is provided in the tension control mechanism  40  (see arrows in  FIGS. 13 and 14 ). In either case of displacement of the gear chassis  43 , the worm gear follower  34  will disengage the worm gear  32  causing the tension to be released in the Bowden cable  36 . A release spring  41  may be used to bias the chassis  43  to its operational engagement. When the compression strength of the release spring  41  is exceeded by the applied tension, the release spring  41  will yield and the gear chassis  43  will automatically disengage by shifting downwardly. The release spring  41  may be further calibrated by means of an adjustment screw  53  ( FIG. 12 ). Alternatively, or additionally, an emergency release mechanism may be provided by a button  42 . Button  42  may be pressed by hand, or squeezed by palm action, to drive the gear chassis  43  sideways and break connection with the worm gear  32 . If the bending moment of the release spring  41  is not sufficient to hold a horizontal register of the gear chassis  43 , the gear chassis  43  may be buffered against a side wall by an elastomeric insert having a slip surface (not shown). 
     In the preferred embodiment, the tubular members  8  of frame  3  are fabricated from 1.25″ steel or aluminum tubing, although PVC tubing of a sufficiently beefy wall construction can be used. The constituents of hingeable joints  13  and T-joints  15  are preferably injection molded from nylon resin. Alternative resins of comparable toughness can be used, such as acrylonitrile butadiene styrene (ABS). The parts can also be machined from aluminum or other metal blanks The hinge pins are preferably steel pins. The fabric web  12  and the hammock  4  may be sewn from canvas, duck or a synthetic woven material, such as polyester. The hammock  4  may be lined with a soft, or napped, material for comfort and abrasion prevention. The occiput collar  5  may be molded from closed-cell foam, such as urethane, and may be attached to the hammock  4  by sewing, by Velcro® hook-and-eye patches, or by other known attachment means. The stabilizer lines  6  may be elasticized “shock cord”, or otherwise rubberized surgical tubing, and may be attached by sewn-in, or Velcro&#39;d-on, D-rings. The gears of the gear chain  32 , and the bushings suspending them, are preferably stock metal components, but may otherwise be custom-molded from nylon. The gear chassis  43  is preferably fabricated as a machined metal part. The dial handle  51  is preferably molded from nylon, or the equivalent. The remaining components of tension control mechanism  40  may be molded from commodity resins, such as polyethylene (PE), polypropylene (PP) or impact polystyrene (HIPS). The Bowden cable is available in standard gauges and essentially unlimited length from stock supply. The release spring  41  is preferably a coil spring of tempered steel composition. 
     In operation, the portable decompression device  1  can be unfolded and extended to its envelope space of approximately 26″ wide by 40″ deep by 27″ high. The erect A-frame  25  forms an isosceles triangle with base angles of approximately 66°. During operation, the patient lies comfortably upon the fabric web  12  with the patient&#39;s head suspended in the hammock  4 . The weight of the patient&#39;s body  2  holds the apparatus in place. The tension control mechanism  40  may be handled with the patient&#39;s upper arms at rest beside the body  2 . By bending from the elbows, one of the patient&#39;s hands may hold the control mechanism while the other hand rotates the dial. The amount of tension to be applied and the cyclical frequency of the stretching and relaxing optimal for invoking imbibition, as well as the preferred critical value  31  defining the safe limit of applied tension, may be proscribed in the individual circumstance by a licensed professional. The portable decompression device  1  may be folded and rolled together with the fabric and control components to reduce size to approximately 8″ in girth and 28″ in length. 
     It is to be understood that the invention is not limited in its application to the details of construction, to the arrangements of the components and to the method of using set forth in the preceding description or illustrated in the drawings. For example, the first vertical angle  22  could be made adjustable in order to customize the pull direction. In addition, the manual tension control  40  could be replaced with a motorized version. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.