Abstract:
Disclosed is a chiropractic instrument capable of achieving the benefits of algorithmic pre-stretch, power-stretch, and recoil and release in reciprocating therapy to human tissue. In particular, that application teaches a plunging-probing technique wherein a barrage of power-stretch impulses is added to a time-modulated ramp of increasing and decreasing stretches, while offering an inherent safety-limit which prevents, upon operator error force, beyond the max given on its label, while providing meaningful tactile feedback to the practitioner. The new idea yields tethered reproducible power-stretches which only occur concurrently with achieving precise, variable, and preset levels of tissue pre-stretch force.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention pertains generally to a chiropractic instrument, but more particularly, is focused on providing an algorithmic afferent modulation instrument that consistently replicates a chiropractic afferent-work-algorithm, while producing up to 200% the work afferent of prior art. 
         [0002]    The advent of the simple ballistic hammer-to-the-anvil thrusting device to provide chiropractic therapy has benefited both patient and practitioner. It offered a directed force hand-saving alternative to traditional hand manipulative treatment, which can be physically stressful and debilitating to the chiropractor with long term practice. Ultimately, research on mechanoreceptors displacement therapy has led to another paradigm, a better understanding of the needs of afferent communication and the technology that serves it. 
         [0003]    A mechanoreceptor is a sensory organ receptor that responds to mechanical pressure or distortion/deformation—by producing an action efferent to the brain. A variety of mechanoreceptors exist in the joints, ligaments, disc; muscles; skin etc. Different types of sensory end organs respond at different thresholds—and to different types of mechanical stimuli such as: a routine of stretch, power-stretch and release, compression, resonance, etc. Countless specialized nerve endings are present throughout the soft tissues of the musculoskeletal system which interact with the central nervous system and coordinate our body movements, our postural alignment, and our balance. When there is a communications breakdown, or when improper information is supplied by one or more of these sensors, efficiency of movement decreases. Often this leads chiropractors to utilize, increasing and sometimes, excessive levels of force. This can be harmful and possibly injurious to the muscles and joints, resulting in problems with postural coordination and/or joint alignment. Beyond being just an annoyance, faulty coordination or misalignments can also be the source of chronic, unresolved pain. An effective afferent-stimulation device is needed to achieve successful tissue-release with lower levels of force. 
         [0004]    Location of Nerve Endings (in the muscles): The most important sensory nerve endings for controlling the muscular system are the muscle spindle fibers and the Golgi tendon organs. Muscle spindle fibers are found interspersed within the contractile fibers of all skeletal muscles, with the highest concentration in the central portion (belly) of each muscle. Muscle spindles respond to changes in the length of muscles. A complex circuitry of these nerve endings, with interconnections in the dorsal horn of the spinal cord, maintains muscle tone and, most importantly, the appropriate tension in the muscles on opposite sides of each joint. Without this functional interconnection, proper joint alignment can&#39;t be maintained, and relaxed, upright posture is almost impossible. 
         [0005]    Golgi tendon organs are located in the junctions of muscles and their tendons. These protective nerve endings exert a powerful inhibitory effect on contraction of the muscle fibers. They are stimulated by appropriate in proximity stretching of the muscle/tendon junction (as when the muscle fibers are contracting too strongly). Golgi tendon organs transmit their information to the spinal cord and cerebellum through large, rapidly conducting nerve fibers, and they can rapidly inhibit a muscle contraction in order to protect the tendon. 
         [0006]    Joint Mechanoreceptors: Surrounding and protecting all joints are tough, fibrous tissues which contain a variety of sensory nerve endings. The input from these specialized sensors keeps the nervous system informed as to the location of the joint and also the degree of stretch, compression, tension, acceleration, and rotation. Multiple simultaneous afferents to a mechanoreceptor facilitate its own efferent, which is the principal purpose of this new design. These joint mechanoreceptors are classified by their anatomy and their neurological function. Type I mechanoreceptors are found in higher densities in the proximal joints. They sense the position of a joint by signaling the joint angle through normal ranges of motion. These help determine postural (tonic) muscle contractions. Type II nerve endings adapt to changes in position, and are most active at onset and termination of movement. These are more densely distributed though the distal joints, and affect phasic muscle actions. Type III mechanoreceptors are high threshold, which means they require considerable joint stress at end ranges before firing. These receptors serve a protective function similar to the Golgi tendon organs. Type IV receptors are free nerve endings located in the ligaments, joint capsules, and articular fat pads which respond with painful stimulus upon extraordinary afferent. They can generate intense, non-adapting motor responses in all muscles related to a joint, resulting in the protective muscle contractions that restrict joint movement. 
       PRIOR ART 
       [0007]    The earliest percussive technique is often referred to as the hammer-to-the-anvil style, where a mass (the hammer) is set into ballistic motion and acquires a certain speed before it collides with a flat-tipped rod (the anvil) which in turn slaps against the patient. U.S. Pat. No. 4,116,235 (Fuhr et al) and variations of it are examples of this early prior art where the thrust is achieved when an internal spring behind a hammer is compressed until an escapement mechanism releases it. The intent of the hammer-to-the-anvil device is typically to overpower and force joint movement or non-compliant tissue into compliance. The chief disadvantages of this design are that it stings uncomfortably, is limited to one hammer-to-the-anvil slap against tissue per trigger, and has limited adjustment range. Moreover, it does not contemplate preload force. The work that it does is limited to the moment of deceleration when the hammer crashes into the anvil. It is not capable of delivering a continuous train of thrusts and is not sophisticated enough to follow an advanced chiropractic afferent-work-algorithm. 
         [0008]    U.S. Pat. No. 7,144,417 (Colloca et al) depicts a more recent implementation of the hammer-to-the-anvil design. In it, instead of a spring, an electrical solenoid propels a ballistic armature (the hammer). Here the intent of a 20 newton preload is to disallow operation at any other preload. Impact force adjustment is via a selector switch, which allows 3 levels of electrical power to the solenoid. This design produces a single hammer-to-the-anvil slap against the tissue, followed by a short train of hammer-to-the-anvil slaps to tissue, said to be 6 Hertz over the interval. The main disadvantages of this design are that it stings uncomfortably and is not capable of delivering a longer continuous train of hammer-to-the-anvil-hits at different pre-selected rates. Furthermore, it is limited to one high hammer speed, one medium hammer speed, or one low hammer speed and one 20 newton preload that if not maintained stops operation. The work that it does is limited to the moment of deceleration when the hammer crashes into the anvil. Colloca is suitable for ballistic—trust only and cannot approach—the ideal and repeatable chiropractic afferent-work-algorithm. 
         [0009]    U.S. Pat. Nos. 6,537,236 (Tucek et al) and 6,663,657 (Miller) also achieve the thrusting force via an electrical solenoid, but shun the hammer-to-the-anvil approach. Rather than a hammer abruptly decelerating into an anvil that abuts body tissue; intended here is still inefficient ballistic acceleration, except that the magnetic armature (what amounts to the hammer itself in prior art) directly impacts the body tissue in contact with it. It can still be noisy and uncomfortable but does avoid the instantaneous slap that a crashing anvil creates against the patient&#39;s skin. Moving the handle to reposition the armature away from the center of the flux field and then holding that specific position is the method of impact force adjustment. When the armature mass is centered inside the solenoid, there will be minimal axial magnetic force; this is also true when the armature exits the flux field. Thus the chief disadvantage is the method of control is counter-intuitive to the user (forward motion may make the force heavier or lighter) and hence unfriendly. For example: Both designs reposition hammer (armature) force by moving the handle forward towards the patient to increase solid-tissue impact force, except force and travel were not designed to have a direct and reproducible relationship. This is evidenced near mid-travel, where even with the handle moving forward, force behaves unpredictably—thereby creating some confusion in the mind of the practitioner. The majority of practitioners have found this concept unsettling and with limited market appeal, since such therapeutic treatments could not be reliably replicated. 
         [0010]    To blunt the end of the rod and guard against pinch point, both Tucek and Miller utilize an often noisy rattling outer spring retained by a nut which is fixed against a linear bearing. After actuation, both Tucek and Miller utilize an inner spring to park the rod against the bumper-stop. In both prior arts, the inner and outer springs lack the defining-characteristics and provide no user-friendly proportion or calibration. 
         [0011]    A demand exists for a device that deviates from the commonplace prior art with near ballistic displacement that impacts on bones and non-compliant tissues. Accordingly, it is a general object of the present invention to provide a safe, economical and user friendly device that facilitates a calibrated chiropractic afferent-work-algorithm that is suited to creating multiple mechanoreceptor afferents. A practitioner thus being interactive with this device for applying the algorithm finds how much work/afferentation will feed and re-educate the brain to effect the release of target tissues so they can move without discomfort. These and other objects and advantages of the present invention will be more readily apparent from a consideration of the following drawings and a detailed description of the preferred embodiment. 
       SUMMARY OF THE INVENTION 
       [0012]    In accordance with one embodiment, the present invention comprises of an algorithmic chiropractic instrument optimized to approximate a chiropractic afferent-work-algorithm for manipulative mechanoreceptor modulation. The present invention is capable of producing a pre-stretch force and power-stretch force that are directly and substantially additive. Unlike any prior art, this new design teaches of an instrument specifically suited to a plunging-probing therapy. The practitioner finds that plunging (manually ramping up the pre-stretch force) acts like a catalyst to steadily increase the instrument&#39;s power-stretch output, up to a safety-limit where it plateaus. Further, the practitioner can increase the afferent work done by dwelling at any intermediate pre-stretch level while using feedback from the instrument to probe for a patient-tissue compliance-response. All of this is achieved with a relatively simple physical input through mechanical and electrical implementation, without resorting to the complications of sensor-driven computer electronics. The pre-stretch force is substantially proportional to a tissue like experience over the spine and amplifies tactile, visual, and audio feedback incorporating the patient tissue release response back to the practitioner. The increases of the pre-stretch force by said practitioner is compensated for by a counter-balancing safety limit drop off of the power-stretch. 
         [0013]    In accordance with one embodiment, the algorithmic chiropractic instrument further comprises of a lever housing and enclosed within the housing is a reciprocating rod and an electrically energized solenoid having a core mounted in the housing so that the actuator handle part of the housing is longitudinally movable relative to the solenoid. The reciprocating rod comprises of an patient-contact end which can receive numerous therapeutic adapters and a non-magnetic governance ring positioned to critically affect the net magnetic flux distribution of the solenoid. 
         [0014]    The reciprocating rod transits through the solenoid and is responsive to the force generated by the solenoid. An inner spring is disposed around the rearward end of the reciprocating rod inside the housing and an outer spring is disposed around the rearward end of the said reciprocating rod outside the housing and compressible. A restricted calibrating adjustment nut is threaded through the rearward end of the reciprocating rod and the position of the adjustment nut governs the tissue pre-stretch upon direct proportional displacement of the inner and outer springs. 
         [0015]    The inner spring, outer spring and nonmagnetic ring all acts to algorithmically tether the ballistic nature of solenoid generated power-stretch to produce an efficient and repeatable chiropractic work algorithm, while producing up to 200% the work afferent of prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0016]      FIG. 1  shows a cutaway view of the present instrument; 
           [0017]      FIG. 2  shows the range of the chiropractic afferent-work-algorithm 
           [0018]      FIG. 3  shows prior arts&#39; unsafe net force combinations of contact pressure and solenoid force; 
           [0019]      FIG. 4  shows protective limiting by the present invention which only allows safe combinations of contact pressure and solenoid force, even with operator error; 
           [0020]      FIG. 5  shows the distinction between the present invention and prior art when it comes to the rate of impact against the patient and how the area under the curve defining the available work-range is increased by factor of about 5 by the combination of pre-stretch and tethering of the solenoid; 
           [0021]      FIG. 6  shows an algorithmic full range manual probe demonstrating ramp up and safety limiting controls; 
           [0022]      FIG. 7  shows a flowchart illustrating interaction between Practitioner and Patient using the present device. 
           [0023]      FIG. 8  shows a cutaway view of an alternative embodiment of the present invention. 
           [0024]      FIG. 9  shows a cutaway view of an alternative embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    Referring to the drawings, there is depicted a chiropractic instrument in accordance with the present invention, depicted generally in  FIG. 1 . The instrument in its preferred embodiment comprises a lever housing which is a combination of housing and handle, where the handle is referred to as a hybrid control-lever  12 . The lever housing is a critical intermediary and the bio-feedback link between the tactile sense of the practitioner&#39;s hand and the palpable compliance of the patient&#39;s tissue. 
         [0026]    A power-stretch assembly comprising a dual coil solenoid  14  is disposed within the lever housing. The dual coil solenoid  14  provides operational power to the stretch assembly which is further comprised of a reciprocating rod  16  with a patient-contact end disposed at the forward end and secured to the reciprocating rod. 
         [0027]    A fan  36  having a specific footprint is provided for airflow to cool the solenoid  14  switches  28 ,  62  and circuitry  24 . Other methods of moving air, including membrane driven pumps may also be utilized. 
         [0028]    The reciprocating rod  16  transits through the solenoid  14  and is responsive to a balance point system comprising: the tissue-resistance force, operator pre-stretch force, and the force generated by the dual coil solenoid  14  such that on activation the reciprocating rod  16  is accelerated axially. The reciprocating rod contains a frontward end and rearward end. Fixed on the reciprocating rod  16  is a governance ring  17  and armature  18 . An inner spring  54  and an outer spring  56 , either side the actuator handle interface, are disposed around the rearward end of the reciprocating rod  16 . A threaded adjustment nut  58  is rotatably threaded onto the rearward end of the reciprocating rod  16  to permit adjustment of the balance point of system compression forces of the springs  54 ,  56 . A linear bearing  19  is used to cover and provide a sliding surface to the threading of rod  16 . Between stops, the approximate 1 mm thread pitch provides a 4-turn-range of calibrated variate positioning for the armature in the magnetic flux field of the wire coil. 
         [0029]    Unlike the ballistic nature of the prior art, the present invention utilizes multiple governance methods to tether the force of the solenoid which accelerates the armature and the reciprocating rod. The present methods of tethering the solenoid  14  is contrary to the teachings of the prior art which insist on maximizing the force of the ballistic solenoid upon impact, which intends to knock bone/hard-tissue into reposition. The present tethering, amplifying, and tactile biofeedback method distinguish the present invention as a device for algorithmically applying a calibrated force that is operator-friendly and can accomplish approximately the chiropractic afferent-work-algorithm of  FIG. 2 . Thus it transfers waves of power-stretch, cumulatively working mechanoreceptor rich tissues as its substantial pre-stretch sustains the sinking biofeedback layer by layer down to the bone, for greater repositioning. Subject to adjustment nut  58  calibrated compression on outer spring  56 , a principal object of inner spring  54  is to provide chiropractor, instrument, and patient interaction. Instrument dynamics follow movements of the hand, which integrates the biofeedback of the variate recoil into a palpable measure of patient response to this afferent-work. By adjusting  58 , the practitioner can proportionally find the operate-point for optimum results. In the preferred embodiment, one full turn of the adjustment knob  58  will enable quantified transference of about 25% tissue pre-stretch, 25% of working range for spring  54 , 25% of the working force for spring  54 , and 25% of the operator afferent modulating force shown in  FIG. 2 ; similar parameter changes at about 50%, 75% and 100%, for turns of 2, 3, and 4, respectively. An object of the inner spring  54  is to equalize operator applied-pressure, patient tissue resistance-pressure, and mechanical solenoid-pressure at a therapeutic tissue stretch level. This creates a patient-operator biofeedback loop in sense perceptible form as the operator, allowed by design, probes synergistically and contributes up to 80% in overall therapeutic afferent work in its preferred embodiment. The inner spring  54 , unlike the purely positional springs of the prior art, is an interactively calibrated multi-rate spring with multiple pitch coils, wire size and diameter combination that creates a spring-rate graduation that at a given percentage is proportional to a tissue-like experience over the spine. In the preferred embodiment, the multi-rated spring  54  either has steeper pitch central or decreased diameter central. 
         [0030]    The outer spring  56  of the present invention acts as an overpowering governance and amplifies recoil that functions to constantly counter and calibrate the force of spring  54  and the solenoid. In the preferred embodiment, the length of 4 thread pitches exposes 100% of the range which allows the adjustment nut  58  to tighten four whole rotations and visually exposes the length of up to 4 thread pitches as an indication of the combined length of stretch and recoil that is at work. This calculated length of adjustment allows spring  56  to govern the pre-stretch 25% per turn which also allows the practitioner to draw from his past patient history or experience and reproduce prior success upon setting adjustable pre-stretch range the same every time. Once effective, this in practice equates to expediting the algorithm with inner spring  54  contributing to reaching/sinking systematically deeper with governance affecting continuously greater populations of mechanoreceptors within patient tissue as the outer spring  56  recoils which manipulatively does tissue release between solenoid pulses and then re-stretching of mechanoreceptors concentrations at the levels that have already been passed through, due to spring  56 &#39;s overpowering governance and recoil dissipation action. Additionally, it&#39;s this spring-rate proportion governed to suit the chiropractic afferent-work-algorithm that is in itself therapeutic due to the proportional change in force level and nature of its stretch modulation probing and the fact that interactively probing itself contributes to the total work done. 
         [0031]    Another novelty of the present invention is the strategic positioning of non-magnetic materials which allows controlled probing of the instrument tip into tissue-under-treatment to achieve slow stretch. The non-magnetic element in the preferred embodiment is depicted as governance ring  17 , which is made of aluminum, and works in conjunction with springs  54 / 56  and the resulting biofeedback pressure-loop to tether the otherwise ballistic force of the solenoid. 
         [0032]    The correct use of the above described chiropractic mechanoreceptor modulation instrument results in novel chiropractic afferent-work-algorithm illustrated in  FIG. 2  that is significantly different from the prior art. The stretching action of the instrument attributed to the ideal interacting multi-rated springs is seen to be adjustable smoothly and continuously from zero to maximum-permissible over the normal range of possible tissue displacement. The solid line shows actual governed performance and the effect of the tethering methods. In addition to position the desired safety limiting feature, the smooth-control region  50  is governed by a cubic equation, rather than a linear one. This compound curve  50  provides for a slower rate of change with displacement at both the lowest and highest stretch levels. This fine-control provides the practitioner a user-friendliness. Furthermore, approximately 80% of the work curve area depicted in  FIG. 2  section  51  is sustained by the therapeutic biofeedback pre-stretch. The therapeutic level of both pre-stretch and power-stretch are directly additive. The pre-stretch being substantially proportional, it serves to induce and expedite resonance compliance. Further, any excess increase of pre-stretch by the practitioner is compensated for by a counter-balancing safety-limit drop off of solenoid power-stretch. This results in a flat curve peak which sustains work level and is what minimizes the effect of achieving power limit with an armature location, which by design is positioned to exit the magnetic flux field proportionally. The flattening of the curve peak is due in part to the algorithmic tethering of the solenoid force. The dashed line presents a purely linear work curve without governing elements such as multi-rated springs. 
         [0033]    Referring to both  FIG. 2  and  FIG. 6 , the area under the work curve created by the solid line can be viewed as the afferent work done on the patient that is the accumulation of the increments of energy expended during the travel of the instrument tip. Standard equations for work performed is dW=F*dx or alternatively dW=F*v*dt. 
         [0034]    Where: 
         [0035]    W=work i.e. the integral of either above differentials 
         [0036]    F=net applied force 
         [0037]    x=displacement distance over which the force is applied 
         [0038]    v=velocity of the instrument tip 
         [0039]    t=time 
         [0000]    Hence the work done on the patient can be viewed as either the area under the curve for tip displacement distance or accumulated time for which the force of the instrument is applied to the patient tissue. For the present invention, each component has an algorithmic function of governing the net force to consistently reproduce the same smooth work curve depicted in  FIG. 2 . Therefore, the net force may be expressed as: 
         [0000]    
       
      
       F=F 
       coil 
       +F 
       inner 
       −F 
       outer 
       −F 
       cushion 
       −F 
       friction 
       −F 
       tissue 
       −F 
       eddy  
      
     
         [0040]    Where:
       F coil =a function of amperes, armature shape and location   F inner =a function of displacement of the inner spring  54     F outer =a function of displacement of the outer spring  56     F cushion =a function of the elasticity of the clamping bumper-cushion   F friction =a function of the accumulated stylus friction   F tissue =a function of the elasticity and damped-compliance of patient tissue   F eddy =a function of the eddy current generated by the magnetic field of the solenoid       
 
         [0048]    The present invention&#39;s ability to algorithmically tether the blunt force of the solenoid, which in turn allows a slow stretch, which may translate to a higher current and possibly overheating of the solenoid. Therefore, in addition to the fan  36 , the present invention also implements a novel coil construction. Typically dual windings solenoid coils have identical turn-counts, e.g. 750 and 750. The present invention utilizes an unbalanced dual coil turn-count which significantly reduces the hot-spot core temperature of the inner winding pushing the heat to the outer winding where it is more readily cooled by convection to the ambient and, in addition, provides for international dual line voltage operation. 
         [0049]    By optimizing armature shape and location in the flux field in conjunction with inner and outer spring parameters, something approximating the ideal algorithmic range of performance of  FIG. 2  has been achieved. As the clinical population&#39;s average tissue-density, weight, and size changes, it is likewise intended that this algorithm will proportionally change, which recognizes that the health professionals using the instrument are palpators. The way to make the instrument user-friendly for them is to have its tactile sense, audio sense and visual sense perception comparable to the average body tissue displacement density. Ignoring what, in the trade, chiropractors call slack (tissue not likely to be revealing), it was found that a mechanical pre-stretch which approximated the progressive increase in palpable tissue resistance experienced with two-finger-straddling the spinous process was a user friendly proportional-relationship to anyone familiar with palpation. Present day ratio (approximately 4 millimeters at 7 pounds) yields this appreciable perception: that operator&#39;s mechanical tactile sensation is relative to human target tissue. Yet when therapy calls for extraordinary displacement, such as an obese patient may require, the machine force against the patient should be safely limited to the instrument rated maximum. Inevitably, due to judgment error, the typical operator instinctively in probing to discern whether the patient requires a level of therapy at or beyond the 100% instrument rating tends to over exert up to about 8 pounds. This can be seen in  FIG. 3  where the operator error preload of the prior art devices leads to beyond specification and possibly unsafe levels of force. The preferred algorithm plot recognizes that the act of over-exertion must be virtually sense-perceptible and takes steps in teaching the user not to over exert the instrument beyond its safely limit.  FIG. 4  shows the ability of the present algorithmic instrument to stay within 100% of the designated safety limitation of the present device; yet this plateau still allows an up to 200% over-exertion of pre-stretch force. 
         [0050]      FIG. 5  is an oscilloscope reading of the smooth and efficient impact trust of the present invention vs. that of the more hammer-to-the-anvil impact trust of the prior art. Curve  55  shows a single trust of a prior art device that fails to govern the force of the solenoid. This curve is very ballistic in nature. In contrast, curve  56  shows a single power-stretch generated in part by the solenoid force of the preferred embodiment of the present chiropractic algorithmic instrument and the difference is exceptional. Curve  56  is noticeably smoother, non-ballistic, and can be constantly reproduced. 
         [0000]      FIG. 6  shows an oscilloscope reading of multiple power-stretch sequence with algorithmic probing pre-stretch. Notice that the dotted line  61  is substantially similar to the afferent-work-algorithm of a single thrust as seen in the solid line of  FIG. 2 . The present  FIG. 6  further shows the governance method at work in tethering the blunt ballistic nature of the solenoid to produce a smooth work algorithm that peaks despite over-exertion. Another important parameter shown in  FIG. 6  is recoil. Each safely limited positive power-stretch of the instrument is immediately followed by a recoil thrust in the opposite direction, though still a net-positive due to the initial pre-stretch force. This variate recoil is one of the sine qua non of this invention. It provides the practitioner with an amplified tactile and audio feedback which incorporates a direct measure of tissue-release in the patient. This variate recoil is chiefly the result of the complex and collaborative tethering action of the inner spring  54 , the Lenz-force due to eddy-current in ring  17 , the threshold set by the initial adjustment of outer spring  56  and balancing practitioner-pre-stretch against the magnetic force of the triggered solenoid. The audio feedback, i.e. the sound created by the spring recoil after each power-stretch, is also algorithmic and unique. As the pre-stretch force changes, the sound pitch changes synchronously, thus providing consistent feedback from patient to practitioner. By design as the instrument exceeds maximum pre-stretch, a distinct sound is produced. 
         [0051]      FIG. 7  shows the flowchart of the patient-operator biofeedback loop focusing on the functions of the practitioner, the preferred embodiment of the chiropractic instrument and the patient. The practitioner while drawing from procedural memory and sensory memory applies initial force to the lever housing based on his training, but then adjusts it in a stepwise manner based on this tactilely and audibly sensed feedback from the instrument. The practitioner also has control over the calibrated adjustment of the instrument which sets the initial threshold for pre-stretch force and produces a variate amplified tactile feedback from the instrument within its range. The instrument controlled by the practitioner applies the afferent work algorithmic force. This calculated and non-ballistic force allows the patient&#39;s brain to reduce resistance to change which leads to tissue release. While applying the chiropractic instrument to the patient, the substantially proportional pre-stretch ratios induce resonance compliance, and the instrument transfers and amplifies tactile feedback incorporating the patient tissue release response back to the practitioner so that once again the practitioner can adjust his own force modulated probing and force according to procedural and sensory memory. 
         [0052]      FIG. 8  depicts an alternative embodiment where the reciprocating rod  16  further comprises of a collar  61 , and the housing further comprise of collar-stop and bumpers  20 . The non-magnetic governance ring  17  acts as a bumper stop wherein the reciprocating rod&#39;s travel length is limited to the space between ring  17  and bumper  20 . The collar  61  also limits the pre-stretch maximum because once collar  61  contacts the outside of the housing, the maximum allowable pre-stretch is reached. The setting of adjustment nut  58  would then govern the position of the collar  61  and ring  17  in conjunction with the housing bumpers  20 . Furthermore, the positions of both collar  61  and ring  17  may be manually and independently altered to approximate or mirror image the pre-stretch concept at the forward-end of the rod to effect a substantially additive variate of pre-stretch, perhaps as layered densities of a foam-cushion-stop depicted as toroids  66  and  67 , which is effectively just an alternate embodiment of multi-pitch springs  54  and  56 . 
         [0053]    In another alternative embodiment, a novel switch integration illustrated in  FIG. 9 , searches at the balance point of forces, effectively floats the threshold of switching action to be synchronous with the set balance-point determined by the adjusting knob  58 . This switch in conjunction with knob  58  makes it more convenient for the practitioner to draw from his past patient history or experience and reproduce the prior therapy level of success upon setting adjustable pre-stretch range noted in the patient&#39;s record and may be implemented to train biofeedback and consistency among operators relative to tissue stretch as operators contact patients with pre-stretch equal to the compression on spring  54 . More specifically, when the extended patient-contact end  34  is displaced coaxially into the body of the patient and the inner-spring  54  is compressed against the inside of the plastic handle in proportion to the pre-stretch. The outer-spring  56  is decompressed relative to the pre-stretch as it releases away from the handle by the action of transferring pre-stretch (otherwise known as a particular prior reproducible point on the algorithm). Among other things, the amount of decompression of  56  is a function of its original adjustment position along the stylus rod  16 . For a given adjustment position, when  56  is secured to the nut  58 , the outer-spring  56  will gap away from the handle surface at a specific magnitude of pre-stretch. A pair of metallic contacts  64  added to the handle in conjunction with the metal of the outer-spring  56  is the preferred way to detect the point of balance or transference the precise occurrence of this pre-stretch induced gap. The simplest pre-stretch sensing contact configuration is a normally-closed electrical pair. The instrument trigger-switch is typically a normally-open contact pair, so an inversion is usually required. This can be easily achieved with an electro-mechanical relay or some other conventional electronic circuit technique. The inverted-pair can then be used in parallel with the trigger to cause actuation in conjunction with the setting of adjustment nut  58 , which thus allows matching to a particular point on the chiropractic afferent-work-algorithm. 
         [0054]    In yet another embodiment, the reciprocating rod  16 , or strategic portions of it, can be made of either magnetic or non-magnetic material so as to allow for a therapeutic magnetic flux field at the patient interface. 
         [0055]    Throughout the specification the aim has been to describe the invention without limiting the invention to any one embodiment or specific collection of features. People of ordinary skill in the relevant art may realize variations from the specific embodiment that will nonetheless fall within the scope of the invention. For example the means of tethering the solenoid is not limited to elements disclosed in the preferred embodiment, the springs  54  and  56  is not limited to any specific tension or shape; they may have electromagnetic, elastic, pneumatic, or hydraulic buffering. The non-ferromagnetic ring  17  can be of any material and could be located anywhere within the housing as long as it affects the magnetic flux force of the solenoid to have proportional interaction. 
         [0056]    The total work done by the chiropractic afferent-work-algorithm of the present invention is not limited as the invention may apply for athletes, an up-sized instrument having the same afferent-work-algorithm proportionality but perhaps with a nameplate rating at approximately 50% higher level of mechanoreceptor modulation energy. This then would require a more powerful winding and dynamically tuned governing spring characteristics and approximately 50% increase for maximum preload. Despite the size increase of the instrument itself, the chiropractic work algorithm of the present invention still proportionally exists. 
         [0057]    Accordingly, the scope of the invention should be determined not by the embodiment(s) illustrated, but by the appended claims and their legal equivalents.