Abstract:
A pneumatically operated chiropractic thruster or manipulator that has a gun shaped body including an upper barrel and lower handle wherein the thrust element is free to move inwardly when depressed against a human body to accomodate automatically different stroke lengths, and the force delivered is adjustable by changing air pressure at the thruster by a rotable needle valve knob control having a predetermined number of indicated settings. The thruster can be operated with a single or a multiple thrust mode upon a single depression of a valve activator trigger.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application is based in part on Disclosure Document No. 481,929, filed Oct. 31, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a pneumatic chiropractic thruster for use in chiropractic adjustment of musculoskeletal structures. More, particularly, this invention concerns an improved pneumatically operated chiropractic-adjusting device for use in spinal manipulative therapy to apply impact forces or thrusts to a human body. 
     BACKGROUND OF THE INVENTION 
     DESCRIPTION OF THE PRIOR ART 
     The chiropractic art is generally concerned with adjusting misaligned body structures by manually manipulating the various joints in the human body. Of more specific interest in the art, however, is the spinal column which is comprised of several interconnected musculoskeletal structures or vertebrae. Unlike other, less critical body structures, the spinal column must be treated or manipulated with extreme caution because of its link with the central nervous system. 
     The human spine is susceptible to many different pathologic abnormalities including misalignment, miscellaneous trauma and pain, and degeneration as a result of age or disease. By employing various physical therapy techniques, though, a chiropractor, or one skilled in the chiropractic art, may be able to successfully treat a pathologic spine. Successful treatment will not only relieve any pain or discomfort that the patient might be suffering, but will also improve the overall quality of life of that patient. 
     One common spinal-adjustment technique involves applying thrusts or forces to the afflicted region of the spine. In particular, this technique involves either “mobilizing” the spine (i.e. passively moving the spine with relatively slow cyclic or oscillatory motion), or “manipulating” the spine (i.e. applying an impulsive thrust or force in a well-defined direction to a specific region of the spine). Depending on professional affiliations, this technique is referred to as chiropractic adjustment, osteopathic manipulation, orthopedic manual therapy, and/or spinal manipulative therapy. 
     There are several well-known procedures or techniques for “manipulating” or administering impulsive thrusts to a spine. One technique involves applying one or more rapid thumb thrusts to misaligned or afflicted vertebrae. Thumb thrusts, however, tend to be both imprecise in magnitude and location and tiresome to administer. Another technique involves using a manually operated chiropractic-adjusting instrument. For instance, U.S. Pat. No. 4,116,235, issued to Fuhr et al. (“Fuhr”) and U.S. Pat. No. 4,498,464, issued to Morgan, Jr., disclose such instruments. 
     Throughout the years it has also been known that power driven devices at times can offer benefits or advantages in use over the manually operated devices. 
     Electric solenoid operated adjustors such as ones described in Evans U.S. Pat. No. 4,841,955 issued in 1989 or Adelman U.S. Pat. No. 4,682,490, issued in 1987, can provide adjusting and controllability benefits over manual devices. However, using an electrical appliance close to the body can be potentially hazardous and even prohibited by governmental regulatory agency rules or regulations. 
     Thus, numerous efforts have been made to develop a pneumatically operated thruster with all of the desired features and benefits required for safe and varied usage of such devices. Examples of such an approach in pneumatic operated thrusters is shown in U.S. Pat. No. 4,716,890, issued in 1988 to Bichel and references cited in the Bichel patent. 
     While the Bichel thruster as described did seek to overcome disadvantages presented in prior art devices, it still did not provide certain features and advantages required to achieve wide spread acceptance and use by chiropractic practitioners. 
     By way of example, it may be noted that such prior devices including Bichel are capable of only delivering a single thrust or stroke, provide only manual adjustability of stroke lengths; provide force adjustment by changing stroke length and change air pressure only at the compressor or supply source. In addition they involve complicated multiple parts designs which make them more costly to manufacture and more difficult and costly to maintain or use. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a pneumatic chiropractic thruster or manipulator for use in chiropractic treatment to apply controlled impact forces or thrusts to a human body wherein a resilient tipped thrust element automatically adjusts itself for stroke length and force applied by an air pressure driven piston member can be conveniently changed at the thruster by changing the air pressure with a rotatable control having predetermined settings. The thruster can also deliver multiple as well as single strokes with a single push of a valve trigger. The thruster has been simplified as its parts and components to lower the costs and render it simpler to use, adjust and service or maintain. 
     Other objects, features and advantages of the invention will become apparent upon reading the following description of a preferred exemplified embodiment of the invention and upon reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side perspective view of an improved pneumatic chiropractic thruster or manipulator with automatic stroke length adjustment and air pressure adjustability at the thruster; 
     FIG. 2 is a cross sectional view of the thruster of FIG. 1; 
     FIG. 3 is a partial cross-sectional view of the thruster head portion showing its initial compression against a body; and 
     FIG. 4 is an exploded parts drawing showing the components of the thruster. 
     While the invention will be described and disclosed in connection with a certain preferred embodiment, it is not intended to limit the invention to a specific embodiment. Rather, it is intended to cover all such alternative embodiments and modifications as full within the spirit and scope of the appended claims. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now specifically to the drawings, FIG. 1 depicts an improved pneumatic chiropractic manipulator or thruster  10  in accordance with the present invention. The thruster  10  has a “gun-shaped” body with an upper barrel portion  12  and a lower handle portion  14 . 
     A thrust element  16  protrudes from the forward end of barrel  12  and it is adapted to receive a removable, resilient tip  18 . The tip  18  may be made of rubber or plastic and it can be interchangeable with different degrees of softness, hardness or durometer ratings as desired. 
     The rear end of the barrel  12  carries a pressure adjuster  20  in the form of a knurled knob controller. 
     At the upper forward portion of handle  14  there is provided a valve plunger or trigger  22 . The lower end of the handle  14  receives a fitting  23  for a supply hose  24  that connects to a compressed air supply  26 . 
     The compressed air supply  26  may be a portable tank or a compressor with typical relief and pressure setting valves as well as other peripheral devices for supplying compressed air safely through a hose  24  of suitable length to the thruster hose fitting  23 . 
     As best depicted in FIG. 2, the handle  14  has a longitudinal bore  28 , threaded at its lower end to receive the hose fitting  23 . The longitudinal bore  28  connects to a horizontal bore  30  that receives trigger valve member  32 . The arrangement is such that air supplied from compressed air supply  26  through the hose  24  is directed through bore  28  and contained until the trigger  22  is depressed. When trigger  22  is depressed, the air can then pass through port  34  into horizontal bore  36  in the barrel  12  and then to vertical bore  38 . The bores  36  and  38  are closed by threaded plugs  40 ,  41 , respectively. 
     In accordance with one of the features of the present invention, air pressure delivered can be adjusted at the thruster itself and there is no need to then move to the air supplier for such adjustments. To accomplish this, the controller knob  20  carries a needle-valve  42  which can be selectively opened or closed by rotation of the knob. Preferably, the knob  20  is held to the needle valve  42  by a set screw  44  (FIG. 4) and the knob is provided with a predetermined number of indicated settings. An arcuate relief slot  46  in knob  20  coacts with a pin  48  to limit the rotation between the numbered or otherwise indicated settings. 
     In accordance with another important aspect of the present invention the stroke length is automatically determined to accommodate different areas of the body. For example, an area like the cervical spine has little muscle and fat so a thrust element does not travel forward very much before it returns or recoils. On the other hand, an area of a large person with a thick fat pad requires a longer stroke length and the thruster head moves further until reaching the vertebrae and hits an area sufficient to recoil. In other words, with a hard surface there is little or no travel distance for the thrust head while a soft thick surface has a longer thrust element movement. 
     Referring to FIG. 2, there is provided a piston member  50  that is driven forward in the barrel bore  51  by pressurized air allowed to enter behind the piston  50  through port  52  with the air pressure force being controllably adjusted with needle valve  42  as previously discussed. 
     In keeping with the present invention, when the trigger  22  is depressed air enters and drives the piston  50  forward until its forward end  54  overcoming the resistance of spring  56  strikes the rear anvil end  58  of thrust element  16 . The thrust element  16 , is free to move inwardly against the spring resistance initially so as shown in FIG. 3 pressing against a body  60  at the outset permits the thrust element to be moved inwardly changing the stroke length as discussed above. 
     The barrel has an exhaust port  62  which is positioned so that air pressure driving the piston  50  is relieved when the port is uncovered by passage of the piston. The placement of the exhaust port  62  restricts the forward translation of the thrust head since the build up of resistance and the force of the compressed spring  56  acts to then restore the piston back towards the rear end of the thruster. Ports  64  in the forward portion of barrel  12  avoid a pressure build up in front of the piston  50  as it travels forward. 
     The simplicity and ease of operating the thruster results since it has a minimal number of parts and it is easy to assemble, disassemble and operate. The thruster head element is held by a threaded sleeve  66  that goes into the threaded entry  68  of barrel bore  51 . The trigger valve assembly  32  is held by a pin  70 . Anvil end  58  of the thrust element  16  is preferably a hard plastic material to deaden impact sound giving the thruster a smooth and quiet operation. 
     In accordance with yet another of the features of the present invention, multiple thrusts are possible with the placement of the exhaust port  62  so that a single depression of the trigger and holding of it in allows the piston  50  to oscillate between covering and uncovering the port  62 . Any recoil occurs at the thrust head end such that the thruster itself has little or no recoil back into the user&#39;s hand. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventor for carrying out the invention. Of course, variations of those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.