Patent Publication Number: US-11020311-B2

Title: Therapeutic device and method for stimulating the anatomy of the cervical spine and neck

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to U.S. patent application Ser. No. 62/444,701, filed Jan. 10, 2017, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention is directed to a therapeutic device for stimulating the anatomy of the cervical spine and neck and more specifically, relates to a therapeutic device and method that provides a massaging function, transmits percussive energy, and optionally provides a vibratory treatment. 
     BACKGROUND 
       FIG. 7  shows the human head  10  with a cervical radius of curvature being identified at  20  and the neck at  25 . With reference to  FIG. 2 , as is known, the cervical spine includes an intricate network of muscles, tendons, and ligaments that provide support and movement. These elements of the anatomy can spasm or become strained, which is a common cause of neck pain and stiffness. The spinal cord travels from the base of the skull through the cervical spine. 
     The cervical spine is comprised of seven vertebrae: C1, C2, C3, C4, C5, C6, and C7. These vertebrae begin at the base of the skull and extend down to the thoracic spine. The cervical vertebrae are cylindrical annular bones, through which the spinal cord travels, that stack up one on top of the other to make one continuous column of bones in the neck. As illustrated and defined herein, the term “facet joints” refers to paired joints located on opposing lateral sides of the spinous process that link a vertebra to its adjacent vertebrae. The facet joints allow the spine to move as a unit. The term “intervertebral disc” refers to one of the small, shock-absorbing cushions located between the vertebrae of the spine. The term “spinous process” refers to the lever-like backward projection extending off each vertebra to which muscles and ligaments are attached. The term “traction” is the process of putting a bone or other parts of the anatomy under a pulling tension to facilitate healing. The term “vertebra” is one of the cylindrical bones that form the spine. 
     SUMMARY 
     In accordance with one embodiment, a therapeutic device for stimulating the anatomy of the cervical spine and neck is provided and includes a housing having an upper portion configured for receiving and cradling the cervical spine and the neck. The therapeutic device includes a motorized rotor assembly having a plurality of rollers. The rotor assembly rotating about a first axis and the plurality of rollers rotating independently from one another and about axes spaced from the first axis. The rotor assembly is configured to transmit percussive and vibratory energy through the rollers to the cervical spine and the neck. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  is a rear and side perspective view of a therapeutic device for stimulating the anatomy of the cervical spine and neck according to a first embodiment; 
         FIG. 2  is a posterior view of the cervical spine; 
         FIG. 3  is a side perspective view of the therapeutic device with an outer housing having been removed; 
         FIG. 4  is a side perspective view of the therapeutic device with a rotor bracket being removed; 
         FIG. 5  is a perspective view of one exemplary roller; 
         FIG. 6  is a side elevation view of the roller; 
         FIG. 7  is a schematic of a human head showing the neck and cervical spine area; 
         FIG. 8  is a side perspective view of an exemplary rotor assembly; 
         FIG. 9  is a side elevation view of the roller assembly; 
         FIG. 10  is another side perspective view of the rotor assembly and rotor bracket with a drive shaft being shown; and 
         FIG. 11  is a side perspective view of the rotor bracket. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
       FIGS. 1-11  illustrate the teachings of the present invention and more specifically, a therapeutic device  100  for stimulating the anatomy of the cervical spine and the neck. The therapeutic device  100  is intended to be a portable device that is placed on a support surface, such as a table, etc. As shown in  FIG. 1 , the therapeutic device  100  has an outer housing or casing  110  that not only contains the working components of the therapeutic device  100  but also is configured to provide an ergonomic interface between the user and the device  100 . In particular, the housing  110  has an upper portion  112  that can have a curved surface (e.g., convex surface). The housing  110  includes a first neck cradle  114  and a second neck cradle  116  that is spaced therefrom. The first and second neck cradles  114 ,  116  are spaced apart a sufficient distance to allow the head  10  and neck  25  of the user to be received and contained therebetween. The first and second neck cradles  114 ,  116  follow the curvature of the upper portion  112  and therefore, each of the first and second neck cradles  114 ,  116  can be curved structures and can be formed as an integral part of the housing  110  or can be coupled thereto. The first and second neck cradles  114 ,  116  can, for example, be cushioned structures (e.g., contain foam or the like that is covered by a covering). 
     As discussed herein, the upper portion  112  can be height adjustable to control the intensity of the massage therapy. 
     While not shown, the housing  110  accommodates an electrical cord that extends from the housing  110  for insertion into a standard electrical outlet. As described herein, the power source can be an electrical outlet via an electrical plug or can be battery powered. 
     The housing  110  also has an opening  115  formed therein between the first neck cradle  114  and the second neck cradle  116 . As described herein, the opening  115  can be formed to have a number of different shapes and sizes so long as the opening  115  provides access to working therapeutic components of the therapeutic device  100  as described herein. The opening  115  is thus preferably centrally located along the top surface of the upper portion  112  of the housing  110 . The opening  115  in the illustrated embodiment thus has a degree of curvature since it is formed along the curved top surface of the housing  110 . 
       FIG. 3  shows the therapeutic device  100  with the housing  110  having been removed to show the working components of the therapeutic device  100 . As shown, a first base plate  120  is provided and serves as the bottom of the therapeutic device  100  that rests on the support surface. The first base plate  120  can be formed to have any number of different shapes with the illustrate first base plate  120  having a rectangular shape defined by a first edge  122 . 
     The housing  110 , which can be thought of as being an upper housing, can be coupled to the first base plate  120  using conventional techniques. For example, the first edge  122  can include one or more hinges  125  that extend along a length thereof. The hinges  125  are configured to mate with complementary structures in the (upper) housing  110  to attach the upper housing  110  to the base plate  120 . The hinged nature permits the housing  110  to pivot relative to the first base plate  120  to allow the housing  110  to move between an open position and a closed position. The first base plate  120  can thus be in the form of a planar structure that can sit on a flat support surface. As discussed herein, the device  100  is intended to be mobile and thus, the first base plate  120  comprises a bottom part of the device  100  and is placed on a suitable support surface. 
     The therapeutic device  100  also includes a motorized rotor assembly  200  that is coupled to the first base plate  120  and more particularly, is movably (e.g., pivotally) coupled to the first base plate  120 . As described herein, the motorized rotor assembly  200  is the mechanism by which energy is transmitted to the cervical spine and neck. The motorized rotor assembly  200  includes its own base plate, namely, a second base plate  210  (a rotor bracket). The second plate  210  can be formed in different shapes and sizes; however, the size of the second base plate  210  is less than the first base plate  120  since the second base plate  210  rests on and lies within the footprint of the first base plate  120 . In the illustrated embodiment, the second base plate  210 , like the first base plate  120 , has a rectangular shape. The second base plate  210  has a first edge  211  and a second edge  213  that is opposite the first edge  211 . 
     The second base plate  210  is movably coupled to the first base plate  120  and more particularly, the second base plate  210  can be pivotally coupled to the first base plate  120 . At the first edge  211  of the second base plate  210 , a rotor hinge  215  is provided and mates with a complementary hinge structure that is associated with the first base plate  120  to permit the second base plate  210  to be hingedly (pivotally) coupled to the first base plate  120 . For example, the first base plate  120  includes a pair of posts or flanges  129  and the rotor hinge  215  is disposed therebetween and a hinge pin  131  extends through the posts  129  and the rotor hinge  215 . 
     The rotor hinge  215  can be in the form of a curved lip as shown in  FIG. 11 . The hinges  125  and hinge  215  are thus located proximate one another. The second base plate  210  has a planar lower surface and a planar upper surface. 
     The second base plate  210  is also biased relative to the first base plate  120  and more particularly, a biasing element  220  is provided to bias the second base plate  210  relative to the first base plate  120 . The biasing element  220  can be in the form of a cushion spring that is anchored to the upper surface of the first base plate  120 . The biasing element  220  can have a base part (mount)  221  that is the part that is anchored to the first base plate  120  and includes a spring that protrudes upwardly from the base part toward and into contact with an underside (lower surface) of the second base plate  210 . The biasing element  220  thus provides a biasing force to the second base plate  210 . In particular, in a rest position, the biasing element  220  causes the second edge  213  of the second base plate  210  to be elevated relative to the first base plate  120  and more particularly, the second edge  213  is higher than the first edge  211  relative to the planar upper surface of the first base plate  120 . It will be understood that when a force is applied to the second edge  213  of the second base plate  210  in a direction toward the first base plate  120 , the biasing element (spring)  220  compresses and stores energy as the second base plate  210  moves toward the first base plate  120 . Conversely, once this applied force is removed from the second base plate  210 , the stored energy in the biasing element  220  is released causing the second base plate  210  to be driven in a direction away from the first base plate  120 . 
     For reasons discussed herein, the second base plate  210  can be thought of as being a hinged plate that is pivotally coupled to the first base plate  120 . Optionally, a vibration motor  230  is provided and is coupled to the second base plate (vibratory hinged plate)  210 . The vibration motor  230  can be any number of commercially available motors that are configured to transmit vibratory energy to the second base plate  210 . One exemplary vibration motor  230  can be an eccentric rotating mass vibration motor (ERM) uses a small unbalanced mass on a DC motor such that when it rotates, it creates a force that translates to vibrations. The vibration motor  230  can be disposed closer to the first edge  211  than the second edge  213  and extends across a width of the second base plate  210 . 
     As shown in  FIGS. 3, 4 and 10 , the vibration motor  230  can be disposed and contained within a motor housing  232  that can be formed of a first part (upper part)  234  and a second part (lower part)  236 . The second part  236  is mounted to the top surface of the second base plate  210  as shown in  FIG. 10 . In  FIG. 10 , the first part  234  is removed to show the vibration motor  230  contained in the second part  236 . The first part  234  and the second part  236  are attached to one another using conventional techniques, such as the use of fasteners. 
     As shown best in  FIG. 11 , the second base plate  210  (hinged plate or rotor bracket) has a pair of spaced side walls  250  that extend upwardly from two opposing sides (edges) of the second base plate  210 . The pair of spaced side walls  250  are parallel to one another and are perpendicular to the planar top surface of the second base plate  210 . The side walls  250  are typically identical and mirror images of one another. In the illustrated embodiment, each side wall  250  is generally triangular shaped in that the side wall  250  has opposing angled side walls  252  that taper inwardly in a direction away from the first base plate  120 . The illustrated two side walls  252  do not intersect and come to a point but instead a top wall  256  extends between the top edges of the two side walls  252 . The top wall  256  can be parallel to the top surface of the second base plate  210 . 
     Each side wall  250  has a through hole (opening)  255  which can be formed to have any number of different shapes and in the illustrated embodiment, the opening  255  is generally rectangular shaped. The length of the opening  255  is oriented in a vertical direction in that it extends between the top surface of the second base plate  210  and the top wall  256 . The opening  255  allows for passage and movement of the drive shaft  410  due to the operation of the percussive energy transfer mechanism. Each side wall  250  also has a plurality of holes  257  that are formed in the second base plate  210  and are arranged around the opening  255 . For example, there can be two pairs of holes  257  along the sides of the opening  255  and a single hole  257  along the top edge of the opening  255 . The openings  255  are axially aligned and the plurality of holes  257  are axially aligned. 
     As shown, the side walls  250  are located at and terminate at the second edge  213  of the second base plate  210 . 
     The motorized rotor assembly  200  also includes a roller assembly  300  that is coupled to the second base plate  220 . The rotor assembly  300  includes a plurality of rollers  310  that are supported by and connected to a pair of laterally opposing rotor hubs  320 . As shown in the figures, the hubs  320  are in the form of plates that each includes a plurality of spokes  322  that extend radially outward from a center portion of the rotor hub  320 . In the illustrated embodiment, there are four spokes  322  that are formed 90 degrees apart from one another. The rotor hub  320  can thus be formed in an X shape. 
     As described herein, the rotor assembly  300  is intended to be accessible through the opening  115  formed in the upper housing  100 . For example, at least one roller  310  can be accessible and pass through the opening  115  to allow contact between the roller  310  and the neck tissue. According to one aspect of the present invention, the degree of which the roller  310  protrudes from the opening  115  is adjustable by adjusting the height of the upper housing  110  relative to the first base plate  120 . In particular, the rear of the housing  110  can be adjusted in an up/down position as a result of the hinged connection to the first base plate  120  and on operation of the actuator or mechanism that permits adjustment. In one exemplary embodiment, there is an actuator for raising and lowering the upper housing  110 . For example, thumbscrews can be provided as part of the upper housing  110  whereupon rotation of the thumbscrews causes raising and lowering of the upper housing  110  relative to the first base plate  120  due to contact between the thumbscrews and the top surface of the first base plate  120 . Other mechanisms are equally possible for raising and lowering the upper housing  110 . 
     Since movement of the upper housing  110  is separate from the rotor assembly  200 , the rollers  310  remain in a rest position while the upper housing  110  is raised or lowered. This results in an alteration in the amount of the roller(s)  310  that are exposed in the opening  115  and more particularly, when the upper housing  110  is raised, less of the roller(s)  310  is exposed, and conversely, when the upper housing  110  is lowered, more of the roller(s)  310  is exposed. 
     The rotor hubs  320  are fixedly coupled to one another so that the two rotor hubs  320  rotate as a single unit. For example, a connector in the form of a cylindrical tube that extends between the center portions of the two rotor hubs  320 . 
     The plurality of rollers  310  are disposed between the two hubs  320  and each roller  310  is rotatably coupled to the two spaced apart hubs  320  such that each roller  310  can independently rotate relative to the others. Each roller  310  is thus rotatably mounted to one of the spokes  322  of each hub  320 . More specifically, a first roller  310  is rotatably mounted to a first pair of spokes  322  (that are spaced apart from one another and are aligned with one another); a second roller  310  is rotatably mounted to a second pair of spokes  322 ; a third roller  310  is rotatably mounted to a third pair of spokes  322 ; and a fourth roller  310  is rotatably mounted to a fourth pair of spokes  322 . As shown in the figures, each roller  310  rotates integrally with a pair of roller shafts/bushings  327  that extend between the respective pairs of spokes  322 . As described in more detail herein, each roller  310  can rotate independently from the other rollers  310 . As shown in the figures, the roller shafts/bushings  327  can be in the form of a shaft that passes through the center of the roller with ends of the shaft extending outwardly from each end of the roller  310 . For example, the roller shafts/bushings  327  can be cylindrically shaped and are intended to be inserted into openings formed in the spokes  322  of the rotors  320  (the roller shafts/bushings  327  freely rotate within these openings). It will be appreciated that other shaft constructions can be used including formation of end protuberances on the roller  310  with the end protuberances being inserted into the openings formed in the spokes  322  of the rotors  320 . 
     The connector (e.g., cylindrical tube) that extends between the center portions of the two rotor hubs  320  is located free of contact and interference with the rollers  310 . 
     The motorized rotor assembly  200  also includes a drive unit  400 , such as a motor, that includes a drive shaft  410  that protrudes and extends outwardly from a casing  405  that contains the motor itself. The drive shaft  410  is best shown in  FIG. 10 . The drive unit  400  can be any number of suitable motors, such as a AC motor or the like. The drive unit  400  is disposed along one of the rotor hubs  320  and is positioned such that the drive shaft  410  passes through center holes  329  formed in the rotor hubs  320 . The drive shaft  410  thus passes between the rollers  310  and is not in contact with any of the rollers  310 . The drive shaft  410  is thus coupled to the two rotor hubs  320  such that rotation of the drive shaft  410  is translated into rotation of the two rotor hubs  320  as a single unit. Operation of the motor thus provides a means for controllably rotating the rotor assembly  300  in a controlled manner. The drive shaft  410  can be attached to the two rotor hubs  320  using any number of conventional techniques, such as a keyed connection between the drive shaft  410  and the two rotor hubs  320 . 
     The connector (e.g., a cylindrical tube) that extends between the center portions of the two rotor hubs  320  accommodates the drive shaft  410  in that the drive shaft  410  passes through the hollow center of the connector. 
     It will be understood that the direction of rotation and the speed of rotation of the rotor assembly  300  can be varied by varying the manner in which the motor operates, including direction of rotation of the drive shaft  410  and the speed of rotation of the drive shaft  410 . 
     Adjacent to each rotor hub  320  is a snail style cam  500 . The cam  500  is positioned along an outer face of the rotor hub  320  and is mounted to the drive shaft  410  such that rotation of the drive shaft  410  causes not only rotation of the rotor hubs  320  but also the cams  500  mounted thereto. Each cam  500  resembles a disk with a center opening through which the drive shaft  410  passes. As best shown in  FIG. 4 , each cam  500  includes at least one and preferably a plurality (e.g., two) cams surfaces  505  that are spaced apart from one another (e.g., 180 degrees apart). The cam  500  can be mounted to the rotor hub  320  by means of one or more fasteners and in the illustrated embodiment (See,  FIG. 8 ), a pair of pins or studs  508  can be used to mount the cam  500  to the outer face of the rotor hub  320 . The pins  508  can be oriented 180 degrees apart. 
     As the cam surfaces  505  of the cams  500  rotate, they contact stationary cam pins  530  which are fixed to inner surfaces of the side walls  250  that form part of the second base plate  210  (rotor bracket). In particular, the stationary cam pins  530  can be press-fit into the topmost hole  257  formed in the side wall  250 . 
     It will be understood that instead of the drive shaft  410  being directly attached to the two rotor hubs  320 , the drive shaft  410  can be directly attached to the two cams  500  as by a keyed connection between the drive shaft  410  and the cams  500 . The result, like the alternative arrangement discussed previously, is the same in that rotation of the drive shaft  410  is translated into rotation of the rotor assembly  300  (including the rotor hubs  320  and rollers  310 ). 
     Floating Nature of the Motor Unit and the Rotor Assembly 
     In accordance with the present invention, both the motor unit  400  and the rotor assembly  300  float in that they are coupled only to the rotor bracket  210  which is support by the biasing element  220  and thus, both structures are movable in the up and down directions relative to the first base plate  120 . The floating nature of the rotor assembly  300  enhances the vibration energy that can be transmitted to the user&#39;s neck tissue since the rotor bracket  210  is not rigidly connected to the first base plate  120  but instead is permitted to move (pivot) about the hinge  215 . 
     Percussive Energy Transfer 
     The therapeutic device  100  also includes a percussive energy transfer mechanism for delivering percussive energy to the neck  25  of head  10 . The mechanism includes a pair of percussive slide housings  600  that are mounted to the outer faces of the two side walls  250  of the rotor bracket  210 . Each percussive slide housing  600  can be mounted to the outer face of the respective side wall  250  using conventional techniques, such as fasteners. For example, the percussive slide housing  600  includes holes that axially align with a set of the holes  257  (the ones on either side of the opening  255 ) and fasteners, such as screws, pass therethrough to mount to the percussive slide housing  600  to the outer face of the side wall  250 . Each percussive slide housing  600  includes a hollow interior space that contains a percussive slide  610  that is mounted to the drive shaft  410  and is biased by a biasing element (percussive slide spring)  620 . The percussive slide  610  is slidably contained within the percussive slide housing  600  such that it can slide and move in an axial direction. The percussive slide  610  is coupled to the drive shaft  410  and thus the two move together as a single structure. The percussive slide  610  is located at one end of the hollow interior space, while the biasing element  620  is located at the other end of the hollow interior space. One end of the biasing element  620  seats against the end of the hollow interior space and the other end seats against and applies a biasing force to the percussive slide  610 . In a rest position, the biasing element  620  forces the percussive slide  610  to one end of the hollow interior space. 
     The rotor drive shaft  410  thus passes through two opposing slide mechanisms each mounted to a vertical support (i.e., side walls  250 ) of the rotor bracket  210 . The rotor is mechanically captured by the rotor bracket  210  in a way allowing only perpendicular translation of the rotor with respect to the horizontal surface (upper surface) of the rotor bracket  210 . This perpendicular translation allows for the transmission of percussive energy to the neck. More specifically, the percussive slides  610  are mounted vertically relative to the horizontal surface of the rotor bracket  210  and thus, the sliding action is along an axis that is perpendicular to the horizontal surface. Since the percussive slides  610  are fixedly attached to the motor shaft  410 , the percussive slides  610  move together with the motor shaft  410 . 
     As previously mentioned, as the drive shaft  410  rotates, the cams  500  rotate into contact with the stationary cam pins  530  (which are fixed to the side walls  250 ) and this causes the drive shift  410 /rotor assembly  300 /motor assembly  400  to translate downward toward the upper surface of second base plate  210  (hinged mounting plate), while simultaneously compressing the two slide springs  620 . Rotation of the drive shaft  410  eventually causes the peak of the cams  500  to rotate past the stationary cam pins  530  instantaneously releasing the stored energy in the slide springs  620  allowing them to propel or translate the drive shaft  410 /rotor assembly  300 /motor assembly  400  upward perpendicular to the upper surface of the second base plate  210  (hinged mounting plate) and toward the user&#39;s neck  25 . It is this repetitive instantaneous translation into the user&#39;s neck  25  that gives a percussive sensation. 
     As discussed here and illustrated in the accompanying drawings, the rotor drive shaft  410  is driven the electric gear motor (drive unit  400 ) and is mechanically coupled to the motor such that the motor translates in direct correlation to the rotor. The entire dynamic mechanism described above is then coupled to the first base plate  120  using a hinge mechanism allowing it to rotate about the hinge pin translating upwardly and downwardly as needed. The hinged mounting plate (second base plate  210 ) rests upon the cushion springs (one pair of springs)  220 , thereby allowing for the upward and downward motion and user comfort. The neck cradle (upper housing  110 ) is mounted on the first base plate  120  and can be adjustable either up or down with respect to the rotor and user preference regarding massage intensity. 
     Roller Construction 
     The rollers  310  are intended to rotate as a result of frictional contact with the neck  25  so as to not allow the roller  310  to slide or skid across the skin of the neck  25 , causing friction and discomfort. The rollers  310  are designed to roll freely up or down the neck  25 , similar to a tire rolling freely across pavement. 
     As shown in particular in  FIGS. 5 and 6 , each roller  310  is contoured to provide anatomical relief or clearance for spinous processes ( FIG. 2 ). Each roller  310  has a pair of roller contact lobes  350  with a relief  360  being located therebetween. The relief  360  is thus a relief for the spinous processes. The roller  310  is constructed specifically to contact the facet joints with the lobes  350 , while the relief  360  accommodates the spinous processes during the rolling action. In other words, the roller  310  has been purposely contoured and sized such that when the lobes  350  seat against the facet joints of the cervical spine, the spinous processes are not contacted by the roller  310  due to their reception within the relief  360 . The facet joints thus represent the targeted anatomy that is treated by operation of the therapeutic device  100 . 
     The rollers  310  can be formed of any number of different suitable materials and in one embodiment, the rollers  310  are semi-rigid in nature and in particular, the rollers  310  can be formed from an elastomer material, rubber, urethane material, etc. It will also be understood that the rollers  310  can come in different sizes to accommodate different anatomies (neck sizes, etc.). For example, rollers  310  could be provided in small, medium and large sizes. 
     It will also be understood that the rollers  310  do not have to have the same construction as one another but instead, the rollers  310  can have multiple different constructions, shapes, or sizes. 
     In one exemplary embodiment and as shown in  FIG. 6 , the diameter (A) of the roller  310  is about 1.50 inches and a recess depth (C) is about 0.46 inches and this construction allows for adequate relief so that the rollers  310  do not come into contact with the spinous processes. Roller contact with the spinous processes could cause discomfort and unwanted cervical deflection to one side or to the other dependent upon the location of contact. 
     Each roller  310  is contoured to provide anatomical contact along the vertical axes of the spinal facets ( FIG. 2 ), while rolling from the lower neck to the upper neck. The roller lobe width (B) (which is about 1.25 inches) is designed to correlate with the average anatomical distance between the vertical axes of the facet joints. As shown in  FIG. 9 , the rotor diameter (R 1 ) is designed to have a 1:1 ratio with the average at rest cervical radius of curvature  20 , thereby providing for optimal positioning and comfort. 
     The timing and amplitude of the physiological undulations imparted by the rotor assembly  300  are modulated by a number of design elements, some of which are fixed and some of which are adjustable. The frequency or timing of undulations is regulated by motor rpm (motor unit  400 ), which may be fixed by design or manually adjustable using a variable speed drive mechanism. Timing of undulation can also be controlled in the design by the number of rotor roller elements (rollers  310 ). The amplitude of the cervical undulation is dictated by several factors in the design, namely a) the number of rotor roller elements (rollers  310 ); b) the distance of the center-line axis of each roller element (roller  310 ) with respect to the center-line axis of the rotor assembly  300  (see r 1 , r 2 , r 3 , and r 4  of  FIG. 9 ); and c) the distance between the axis of rotation of each roller  310  and the axis of rotation of the rotor  320  in relation to the corresponding distance associated with adjacent rollers (r 1 , r 2 , r 3  and r 4 ). It will also be appreciated that this distance can vary from roller  310  to roller  310 . 
     In addition, roller contact pressure can be adjusted by changing the height of the neck cradles  114 ,  116  and upper housing  110  with respect to the height of the rotor  320 . To ensure comfort and safety, the entire rotor/motor assembly is hinged and mounted on springs  220  allowing it to self-adjust its position based upon human contact (i.e., application of force due to head and neck movement). This provides a cushioning effect when positioning the neck onto the rollers  310 . 
     To generate the percussive effect of the rollers  310 , the rotor assembly  300  is spring loaded with two compressive springs  620  located lateral to the rotor assembly  300 . The springs  620  are compressed as the rotor assembly  300  rotates using two opposing snail/drop cam mechanisms, also located lateral to the rotor hubs  320 . As the rotors  300  rotate, it is retracted away from the neck as the springs  620  are compressed and then virtually instantaneously released back toward the neck creating the percussive response and accompanying physical sensation. The intensity of percussion is modulated by the following design factors: a) the stiffness of the compression springs  620 ; b) the radius of the cam circle; c) the height of the peak of the cam profile; and d) the angle of the drop after the peak. The timing of percussion can be modulated by the following factors: a) the number of cam peaks and b) the number of rotor rotations per minute (rpm). 
     It will be appreciated that the rotors  320  are actively driven by the motor unit  400 , while the rollers  310  themselves are passively driven as a result of contact with the skin of the user as well as the rotation of the rotors  320  themselves. 
     It will also be understood that the device  100  can include one or more switches or actuators for controllably turning on and off the unit. In addition, it can be appreciated that the vibration motor can be controlled separate from the motor unit  400  that controls rotation of the rotor assembly. In this way, the user can disable the vibration mode if desired. It will also be appreciated that heating elements (conductive wires, etc.) can be incorporated into the upper portion of the housing  110  and in particular, in the cradles  114 ,  116 . 
     Advantages and Exemplary Applications 
     The present invention provides a number of advantages over prior art treatments including, but not limited to, the following: 1) muscular relaxation; 2) increased localized blood flow; 3) increased localized dispersion of interstitial fluid; 4) improved flexibility and mobility; 5) increased joint elasticity; 6) improve cervical curve over time; 7) pain reduction; 8) improved sleep response; and 9) better quality of life. 
     The therapeutic device  100  can be used in a number of different applications including, but not limited to, neck massage and post-surgical therapy. In one exemplary embodiment, the therapeutic device  100  can have the following dimensions: 9×10×6.5 inches. However, this is merely exemplary and the device  100  can be formed in other sizes. 
     It will be understood that the foregoing dimensions are only exemplary in nature and therefore are not limiting of the present invention. 
     It is to be understood that like numerals in the drawings represent like elements through the several figures, and that not all components and/or steps described and illustrated with reference to the figures are required for all embodiments or arrangements. 
     The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes can be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the present disclosure, which is set forth in the following claims.