Abstract:
A hand held massage unit used for therapeutic purposes such as to loosen and mobilize bronchial secretions in patients, to improve blood circulation, and to relax muscles. The massage unit includes a vibration-free motor unit having a rotating output shaft directly connected to a vibratory head assembly. The rotational motion of the output shaft is transformed into oscillating orbital motion about the shaft centerline in the adapter portion of the vibratory head assembly through an offset cam integrally formed as part of a counterbalanced eccentric. Counterweights within the eccentric reduce the vibrations transmitted to the user&#39;s hand and isolate the oscillating vibration of the vibratory head assembly. Undesired rotation of the vibratory head assembly is prevented by a mounting construction between the oscillating adapter components and a stationary portion of the vibratory head assembly secured to the motor unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates to medical devices in which medical benefits are achieved through the application of vibratory force to a patient&#39;s body. More particularly, the present invention is a portable hand-held massage unit which may be used to loosen and to mobilize bronchial secretions in the patient&#39;s body, or used to apply force to various parts of a body such as the legs, to improve the circulation of blood, mobilize edema fluids, or to relax muscles, while simultaneously reducing the level of vibration felt by the user holding the unit. 
     In the prior art, various methods and devices have been employed for these purposes. One method used to loosen bronchial secretions is hand massage and percussion. Hand massage techniques require a nurse or other attendant to use his or her hands to strike the back or chest of the patient to cause a loosening of secretions within the patient&#39;s lungs. This can be painful, and may result in broken ribs or severe bruises, especially in infants and elderly patients. Additionally, the hand may be cupped prior to striking the back or chest of the patient, providing a suction at the point of impact. Such cupping however, can similarly result in bruises and broken bones, and is considered by many to be ineffectual. 
     Percussion type massagers have also been used to loosen bronchial secretions. In their use, the massager is placed upon the back or the chest of the patient, and the massager is operated such that a vibrating member is forced in and out towards the patient. This percussion-type movement loosens the bronchial secretions, but does not mobilize the secretions to move them out of the congested area. 
     Another type of massager unit that is used is the oscillation type, in which the vibrating member rotates about an axis perpendicular to the chest or back of the patient when it is applied. This type of unit provides a massaging circular oscillation force to the body but does not give percussion to loosen the secretions so that they may be mobilized. Additionally, the parallel force is in a circular pattern rather than unidirectional. 
     Percussion-type and oscillation-type massagers have additionally been employed to improve blood circulation. However, these massaging devices do not provide a uni-directional impulse to blood flowing in a vessel and the oscillation-types furthermore have their principle vibratory effect near the surface level of the skin and do not have a substantial effect upon deeper venuous flow. Previously, to improve blood circulation an attendant would wrap his or her hands around a patient&#39;s ankle and then move them upward, pressing tightly at the same time, in order to squeeze blood flow in the direction of the heart. This is a very difficult procedure, and strenuous work on the part of the attendant. Alternating pressure belts have been used to provide similar results in leg circulation. The belts consist of a series of air bags wrapped around the patient&#39;s leg, each continuously going through the cycle of having pressure increase from the bottom of the leg towards the top, such that there is a squeezing impulse forcing the blood flow up the leg towards the heart. These systems are complex, and requiring difficult synchronization and the total encasement of the patient&#39;s legs. 
     Similar problems arise in the prior art techniques used to relax muscles which have become tense and stiff due to a build-up of lactic acid in the muscle tissue resulting from an inability to rapidly eliminate waste products. Prior art massagers apply percussion or oscillation motion to the muscle, but do not give a continual directional stroke to the muscle to mobilize the waste produces in a direction consistent with the normal direction of blood flow in the muscle. 
     Regardless of the type of procedure in which these various percussion-type and oscillation type massage unit are employed, these devices all transmit a significant amount of the vibratory energy produced to the hands of the user through the housing Long term exposure to these vibrations on the part of a nurse or attendant using these massagers on a regular basis can result in repetitive motion type injury, including the development of Carpel Tunnel Syndrome. Additionally, the transmission of significant vibrations back through the massage device can reduce the useful service life of the device by producing excessive wear and tear on the bearings associated with the drive motor. 
     The prior art has attempted to deal with these problems, for example, the device described in U.S. Pat. No. 4,102,334, manufactured by the assignee of the present invention incorporates a transmission cable between the motor drive shaft and the vibrating components, reducing the level of vibration in the motor and housing, but significantly increase the bulk of the device, and often requiring a separate stand or support for the motor housing. 
     SUMMARY OF THE INVENTION 
     Among the several objects and advantages of the present invention are: 
     The provision of a new and improved massage unit for applying oscillatory motion to a patient&#39;s body; 
     The provision of the aforementioned massage unit in which the massage unit is a self-contained portable unit; 
     The provision of the aforementioned massage unit in which vibrations produced by the oscillatory motion are isolated from the user&#39;s hands; 
     The provision of the aforementioned massage unit in which a counterweight reduces the vibrations transmitted to the user&#39;s hands by counterbalancing an off-center mounting of the oscillating components; 
     The provision of the aforementioned massage unit in which the counterweight is located adjacent the off-center mounting to isolated the vibrations of the oscillating components and to reduce multi-axial twisting; 
     The provision of the aforementioned massage unit in which the oscillating components are directly driven by a motor output shaft; 
     The provision of the aforementioned massage unit in which various adapters may be attached to the oscillating components; and 
     The provision of the aforementioned massage unit in which a right-angle adapter may be attached to the oscillating components to produce a percussion-type motion. 
     Briefly stated, the portable massage unit of the present invention is used for therapeutic purposes such as to loosen and mobilize bronchial secretions in patients, to improve blood circulation, and to relax muscles. The hand-held massage unit includes a vibration-free motor unit having a rotating output shaft directly connected to a vibratory head assembly. The rotational motion of the output shaft is transformed into oscillating orbital motion about the shaft centerline in the adapter portion of the vibratory head assembly by means of an offset cam integrally formed as part of a counterbalanced eccentric. Counterweights within the eccentric reduce the vibrations transmitted to the user&#39;s hand and isolate the oscillating vibration of the vibratory head assembly. Undesired rotation of the vibratory head assembly is prevented by means of a rubber boot secured between the oscillating adapter components and a stationary portion of the vibratory head assembly secured to the motor unit. Applicators suitable for various medical need may be secured to the adapter components, including a right-angle applicator capable of converting the oscillating vibrations into a percussion-type motion. 
     The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings which form part of the specification: 
     FIG. 1A is an exploded view of the portable hand-held massage unit of the present invention; 
     FIG. 1B is a wiring schematic for the electrical connections between the speed control and motor; 
     FIG. 2A is a side view of the internal structures of the right side of the motor housing; 
     FIG. 2B is a side view of the internal structures of the left side of the motor housing; 
     FIG. 3A is a side illustration of the back bearing plate; 
     FIG. 3B is a side sectional view of the back bearing plate of FIG. 3A; 
     FIG. 3C is a top view of the back bearing plate of FIG. 3B; 
     FIG. 4A is a top view of the counterbalanced eccentric; 
     FIG. 4B is a side view of the counterbalanced eccentric of FIG. 4A; 
     FIG. 5A is a bottom view of the adapter ring; 
     FIG. 5B is a side sectional view of the adapter ring of FIG. 5A; 
     FIG. 6A is a side sectional view of the front bearing plate; 
     FIG. 7 is a perspective view of the driveshaft; and 
     FIG. 8 is a side sectional illustration of the assembled vibrator head assembly. 
     Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description illustrates the invention by way of example and not by way of limitation. The description will clearly enable one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what we presently believe is the best mode of carrying out the invention. 
     The portable massage unit, generally depicted in the drawings as  10 , has components which include a motor assembly  12  and a vibrator head assembly  14 . The motor assembly  12  transmits rotary power through a direct coupling  16  to the vibrator head assembly  14  wherein the rotational movement is converted into oscillating orbital motions. 
     The motor assembly  12  includes a motor housing  18  (FIG. 1A) within which is an axially mounted DC motor  20 , and a motor control assembly  22 . The motor housing  18  is a two-piece injection-molded plastic component, consisting of interlocking left and right sides  24 A,  24 B, (seen in FIGS.  2 A and  2 B), and is suitable for gripping by one or two hands. When assembled, the housing  18  comprises a flat base  26 , a generally cylindrical body portion  28  enclosing the motor  20 , and a bell-shaped adapter enclosure  30  partially surrounding the vibrator head assembly  14 . The left and right sides  24 A,  24 B are secured together in a standard fashion by screws  32 A-F passing through matching internal bosses  34 A-F. Internal reinforcing ribs  36 A-D increase the structural integrity of the housing  18  and retain the motor  20  in a fixed position. Molded into the exterior surface of the body  28 , finger grips  38  provide a suitable gripping surface for the user. Formed adjacent the finger grips  38 , recesses  40 A,  40 B receive soft pads  42 A,  42 B, (FIG. 1A) which aid in reducing vibrational motion transmitted to the user&#39;s hands. The soft pads  42 A,  42 B may be composed of a rubber or silicone material, and are preferably bonded to the body  28  by a suitable adhesive. 
     Within the housing  18 , the motor control assembly  22  regulates the operation of the massage unit  10  by controlling the flow of electrical power to the DC motor  20 . Electrical power is received by the motor control assembly  22  through a conducting cable  44 , preferably a hospital grade three-line power cord with a standard three-prong adapter  45 , entering the motor housing  18  through a cable opening  46  in the base  26 . Surrounding the base of the conducting cable  44  as it enters the cable opening  46  is a strain relief  47 , adapted to prevent excessive bending or pulling on the cable. 
     As is well known in the art, the motor control assembly  22  includes a voltage varying potentiometer  48  and associated circuitry to regulate the electrical power distributed to the motor  20  (FIG.  1 B). The potentiometer  48  is positioned adjacent the inner surface  50  of the base  26  such that a rotating control shaft  52  protrudes through an opening  54  in the base  26 . As best shown in FIG. 1, a concentric threaded sleeve  56  surrounds the lower portion of the control shaft  52  to receive nuts  58 A,  58 B and a lock washer  60 . Nut  58 A and washer  60  are threaded over the sleeve  56  prior to the positioning of the potentiometer  48  such that the nut  58 A may be tightened to clamp the lock washer  60  against the inner surface of the base  26  after the potentiometer  48  is fitted within the housing  18 . Nut  58 B, threaded onto the control shaft  52  after it is properly positioned, it tightened directly against the outer surface of the base  26 , clamping the control shaft  52  and potentiometer  48  securely to the housing  18 . 
     The operation of the motor  20  is regulated through a control knob  62  press fitted onto the protruding portion of the control shaft  52 . Rotation of the control knob  62  correspondingly rotates the control shaft  52 , altering the voltage levels within the potentiometer  48 . The operational speed of the motor  20  is directly proportional to the potentiometer voltage levels, hence rotation of the control knob  62  in an increasingly “on” direction increases the potentiometer voltage and correspondingly the rotational speed of a threaded output shaft  64  of the motor  20 . The rotation motion of the motor output shaft  64  is in turn transmitted directly to the components of the vibrator head assembly  14  mounted within the bell-shaped adapter enclosure  30 . 
     The vibrator head assembly  14  (FIG. 8) includes a driveshaft  66 , a back bearing plate  68 , a counterbalanced eccentric  70 , and a front bearing plate  72 . As shown in FIGS. 1 and 8, the output shaft  64  and the drive shaft  66  define a direct drive connection for the head assembly  14 . The vibrator head assembly  14  is assembled around the driveshaft  66 , and fitted with the adapter enclosure  30  such that the forward end  74  of the head assembly  14  extends beyond the forward edge  76  of the housing  18 . The driveshaft  66  axially traverses the vibrator head assembly  14 , and includes a fitted tip  78  axially aligned with the threaded motor output shaft  64 . The fitted tip  78  of the driveshaft  66  includes a recessed shoulder  80 , sized to fit over a non-threaded portion of the motor output shaft  64 , and a smaller-diameter inner threaded bore  82 , with threads  84  corresponding to the threads on the threaded portion of the motor output shaft  64 . The vibrator head assembly  14  is secured to the motor output shaft  64  by threading the fitted tip  78  onto the output shaft  64  until the threaded portion of the shaft is fully seated within the threaded bore  82 . A “C” clip  86  is then fitted within an annular recess  88  on the motor output shaft  64 , securing the vibrator head assembly. Rotational motion of threaded motor output shaft  64  is directly transferred to the fitted tip  78  and driveshaft  66  through the threaded connection. 
     Positioned directly forward of the fitted tip  78 , the inner races of bearings  90  and  92  are press-fitted around a bearing support portion  94  of the driveshaft  66 . The inner race of bearing  92  additionally rests against a shoulder  96  formed against the rearward edge of the driveshaft center portion  98 . A circumferential groove  100  adjacent the rearward end of the bearing support  94  receives a snap ring  102  which retains bearings  90  and  92  in position on the bearing support  94 . 
     The back bearing plate  68  shown in FIGS. 3A-3C has an axially located central bore  104 , which is press fitted around the outer races of bearings  90  and  92 . As is shown in FIG. 3, the back bearing plate  68  includes a cylindrical body  106 , and an enlarged annular flange  108  extending perpendicular to the axis of rotation of the drive shaft  66 . Mounting tabs  110  and  112  are integrally molded perpendicular between the body  106  and flange  108 , on opposite sides of the central bore  104 . Each mounting tab  110 ,  112  includes a bracket hole  110 A,  112 A sized to press-fit around a reduced diameter end  114  of an internal boss  34 A,  34 B adjacent the bell-shaped adapter enclosure  30 . When assembled, screws  32 A,  32 B passing through internal bosses  34 A,  34 B secure the back bearing plate  68  in a fixed position relative to the housing  18 . The back bearing plate  68  correspondingly supports the driveshaft  66 . 
     Forward of the bearings  90  and  92 , the center portion  98  of the drive shaft  66  serves as a spacer between the forwardmost bearing  92  and the counterbalanced eccentric  70 . The counterbalanced eccentric  70 , shown in FIGS. 4A-4B, is formed from molded plastic, and includes a semi-cylindrical axial bore  118  which is press-fitted around a longitudinally flattened key portion  120  of the drive shaft  66 . The interlocking between the semi-cylindrical axial bore  118  and the flattened key portion  120  prevents the eccentric  70  from rotating relative to the drive shaft  66 . Essentially dish shaped, the eccentric  70  includes a forward-facing flange  122  along the outer circumference  124 , and both a rear sleeve  126  extending axially rearward around the drive shaft  66 , and an integrally molded offset cam  128  extending forward around the flattened key portion  120 . The integral offset cam  128  is positioned such that the point of greatest offset  130  is orientated on the opposite side of the drive shaft  66  from the flattened face  132  of the key portion  120  as best seen in FIG.  4 A. An arcuate shaped counterbalance weight  134  is integrally secured within a depression  136  in the forward facing flange  122 , spanning an arc of approximately  120  degrees and centered perpendicular to the flattened face  132  as best seen in FIG.  4 A. The counterbalance weight  134  is preferably composed of a dense material, such as lead, and produces a flywheel effect enhancing the performance of the motor  20  and minimizing the vibrations transferred along the drive shaft  66 . The counterbalance weight  134  does not extend beyond the outer circumference  124  of the eccentric  70 . 
     Positioned forward and around the outer circumference  124  of eccentric  70 , the front bearing plate  72  shown in FIG. 6A, is symmetrical in design, and includes an axial cylindrical bore  136  which receives the outer race of bearing  138  by a press-fit. The inner race of bearing  138  is press-fitted around the outer circumference  140  of the offset cam  128 , such that the front bearing plate  72  is fitted directly adjacent the forward surface of the eccentric  70 . As seen in FIG. 8, the forward portions of the inner and outer races of bearing  138  are supported by a washer  142  with an offset bore  144  fitted over a threaded end  146  of the drive shaft  66 . A castle-nut  148  is threaded and locked onto the threaded end  146 , securing the washer  142  against the forward bearing plate  72  and holding the bearing  138  firmly against the eccentric  70 . 
     The forward bearing plate  72 , being mounted about the bearing  138  and the offset cam  128  is therefore eccentrically mounted such that rotation of the drive shaft  66  and eccentric  70  causes the forward bearing plate  72  to oscillate in an orbital motion. The forward bearing plate  72  includes an annular flange  150  extending both forward and rearward along the outer circumference  152  of the bearing plate  72 . The rearward projection  154  of the annular flange  150  surrounds an longitudinal portion the outer diameter of the eccentric  70  with sufficient clearance to avoid contact during the oscillating motion of the forward bearing plate  72 . The forward portion  156  of the annular flange  150  defines an annular groove  158  between the flange  150  and a shoulder  160  formed in the forward surface  162  of the bearing plate  72 . A threaded adapter ring  164  shown in FIGS. 5A-5B, having a large diameter axially threaded bore  166  is press fitted within the annular groove  158  and bonded to the forward bearing plate  72 . The adapter ring  164  provides a threaded connection point for the various massage attachments (not shown). 
     The portion of the annular flange  150  extending rearward from the forward bearing plate  72  additionally serves as a forward mounting point for an open-ended cylindrical rubber boot  168 . The rubber boot  168  is secured to the outer circumference of both the forward plate annular flange  150  and the back plate annular flange  108 . As thus described, the oscillating member is secured to the housing along the back plate or support through the rubber boot  168 . The rubber boot  168  stabilizes the vibrator head assembly  14 , and prevents circular rotation of the forward bearing plate  72  relative to the secured back bearing plate  68 , while including sufficient elastic characteristics to permit the forward bearing plate  72  to oscillate in an orbital motion relative to the back bearing plate  68 . 
     In operation, the portable massage unit  10  can be gripped about the housing  18  with one or two hands. Preferably, only one hand is needed, and the unit  10  can thus be held by either an attendant or by an individual patient such that the various massage adapters (not shown) threaded to the adapter ring  164  are in contact with a part of the body, such as the chest, in the position desired. With the control knob  62  in an “on” position, the rotation of the motor  20  is transmitted directly to the vibrator head assembly  14  through the locking sleeve  80  from the output shaft  64  to the driveshaft  66 . Axial support of the driveshaft  66  is provided by the bearings  90  and  92  which are held in position within the central bore  104  of the secured back bearing plate  68 . 
     The rotation of the driveshaft  66  in turn rotates the eccentric  70  secured forward of the back bearing plate  68 . The offset cam  128  on the forward surface of the eccentric traverses an orbital path during the rotation of the eccentric  70 . Correspondingly, the forward bearing plate  72  fitted on bearing  138  around the offset cam  128  oscillates in an orbital motion. A massage adapter threaded onto the adapter ring  164  will oscillate in the same orbital motion as the forward bearing plate. 
     As the portable massage unit  10  and massage adapter are moved inward towards and across the body surface, the massage adapter thereby imparts to the patient and angular force produced by both perpendicular and parallel components with respect to the body surface to which the massage adapter is applied. This movement imparts a percussive force against the patient&#39;s body as well as a directional stroking force across the surface of the body. The directional stroke depends upon the direction of the orbital movement of the massage adapter, and in the direction that the adapter moves across the body. 
     The percussive force of the massage adapter acts to loosen bronchial secretions while the directional force has the effect of mobilizing the secretions in the direction of the directional stroke. The massage unit  10  can thus be placed against the torso in selected positions to mobilize bronchial secretions away from an area in a chosen direction. 
     The portable massage unit may also be used to improve blood circulation in parts of the body such as the legs. In this case, the massage adapter is placed along the leg at a location where improved circulation is desired such that the massage adapter will have a directional stroke in the direction in which increased blood flow is desired. While the offset cam  128  oscillates in the vibrator head  14 , the forward bearing plate  72  and attached massage adapter impart a force to the blood vessels so that the blood is forced in the preselected direction through the blood vessels. Thus, the massage unit  10  can be placed to propel blood from the legs towards the heart, or toward another body area. 
     During the operation of the portable massage unit  10 , the bell-shaped adapter enclosure  30  of the housing  18  acts to prevent the hands or other body parts from being harmed by any of the moving parts of the massage unit  10 . Additionally, the soft pads  42 A,  42 B on the exterior of the body  28  and the counterweight  134  in the eccentric  70  act to isolate the user&#39;s hands from the vibratory motions produced by the offset cam  128 . Substantially reducing the vibrations transmitted through the direct connection between the driveshaft  66  and the motor output shaft  64  correspondingly reduces the risk of repetitive motion injury to the user. 
     The various massage adapters which may be threaded onto the adapter ring  164  may include a variety of shapes and sized, each specifically designed to provide oscillating and percussion forces at varying intensities to various parts of the body. Massage adapters may be quickly and easily interchanged by simply unscrewing the current massage adapter from the adapter ring  164  and screwing in another massage adapter having the desired characteristics. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.