turning now to fig1 through 3 , the same illustrate a first and preferred embodiment of the present invention . the mobilizer device 10 of the present invention comprises first and second substantially spherical balls 12 and 14 independently mounted on a shaft 16 ( note fig2 ) which also forms at its ends a pair of handles 18 and 19 . as will be described in more detail subsequently , fig4 - 6 illustrate several different ways of using the mobilizer device 10 , and fig7 shows the relationship of the device to the spine . each of the balls 12 and 14 preferably is of identical construction . they comprise inner rotating balls 22 and 24 disposed on respective sleeves 26 and 28 which are disposed for rotation on the shaft 16 . the inner balls 22 and 24 have an outer soft resilient covering 32 and 34 , respectively . a pair of plastic washers or rings 36 and 37 are affixed to confronting faces 38 and 39 of the respective balls 22 and 24 . plastic collars 42 and 43 are similarly affixed to the outer ends of the balls 22 and 24 . resilient covers or sleeves are disposed on opposite ends of the shaft 16 to form the handles 18 and 19 to provide a resilient gripping surface for comfort of the operator in the mobilization treatment . the inner balls 22 and 24 preferably are formed of polyethylene foam or other suitable foam like plastic material , and the outer coverings 32 and 34 are formed of vinyl foam . the sleeves 26 and 28 are secured within axial openings 48 and 49 of the inner balls 22 and 24 and are secured in any suitable manner , such as by a suitable adhesive . these sleeves facilitate rotation of the balls 22 and 24 and act as sleeve bearings on the shaft 16 . although the sleeves 26 and 28 and the washers 38 and 39 are shown as separate components that can be affixed to the respective balls 22 and 24 , they can be integral or integrally molded with the balls 22 and 24 , it only being necessary that some form of sleeve 26 and 28 be provided to form a relatively low friction bushing on the shaft 16 , and the rings 38 and 39 be provided to form a relatively low friction confronting bearing surfaces for the two balls . the collars 42 and 43 preferably are fixed to the shaft 16 and form bearing surfaces between the handles 18 and 19 and balls 22 and 24 to prevent abrasion thereof and serve to retain or position the rotating sleeves 26 and 28 . the handles can be in the form of resilient covers 44 and 45 . it will be noted that the configuration of the balls 12 and 14 of the fig1 - 3 embodiment for the most part are spherical , but they smoothly form into almost an elliptical shape because of the large diameter confronting sections 52 and 54 , as well as the outer but smaller diameter and thus less pronounced ends 56 and 58 . this spherical to elliptical ball shape is provided for optimal mobilization of the areas about the spine , and is necessary to mobilize the facet joints of the spine . this particular shape enables forces to be applied to the transverse processes of the spine while clearing the midline spinous processes . the elongated confronting areas 52 and 54 also help space apart the major spherical portions of the balls 12 and 14 to facilitate an effective massaging action about the spinal area . in this regard , note fig7 wherein the present device 10 is diagrammatically shown applied to the vertebrae 60 of the spine 61 . thus , the present device is designed so that the balls 12 and 14 straddle the spine and may be placed at the facet joint areas located about the spine . the combination of the balls 12 and 14 and their shape result in an efficient mobilizing device which can effectively mobilize the facet and other joints , and yet can be used by the patient without the assistance of a medical practitioner . the outer layers or ball coverings 32 and 34 are easily compressed and provide elastic contact elements to the spinal area . the device 10 of the present invention can be used in several ways either by the individual or by another . in this regard , fig4 illustrates a patient 62 laying face down with an operator 63 applying the device 10 to the spinal area of the patient . since the construction of the device 10 minimizes the risk of damage to the spine and other back areas , the operator may be a non - medical practitioner such as a spouse or friend of the patient . the device 10 is simply rolled up and down the back of the person being treated , with the balls 12 and 14 straddling the spinal area ( note fig7 ) and rotating so as to best mobilize the facet joints . the total force used is determined by the amount of weight applied to the handles 18 and 19 . fig5 shows a person using the device 10 of the present invention by placing the device underneath his / her own back 62 and moving back and forth as indicated by an arrow 64 over the device 10 which rests on the floor 65 . in this way , the spinal area of the person can be moved back and forth over the device 10 as the balls 12 and 14 rotate with respect to the back and the floor 65 . fig6 illustrates a similar arrangement wherein the device 10 is placed between the back of the person 62 and a wall 67 . the person moves in the direction of the arrow 68 to cause the device 10 and the balls 12 and 14 to rotate along the wall 67 and the back in the spinal area . it should be noted that grade i through iv mobilizations can be achieved with the operation as illustrated in fig4 grades iii through v can be achieved using the operation of fig5 and grades ii through iv can be achieved with the operation as illustrated in fig6 . the outer covers 32 and 34 are compressed , as are the inner balls 22 and 24 to some extent , during the rolling action , but the degree of overall compression is limited by the hardness or density of the inner balls 22 and 24 resulting in effective treatment which does not bruise the patient and which is somewhat comparable to the cushioned pressure provided by the heel of the human hand but with a stretching and rolling action which is difficult to produce with the hand alone . turning again to the specific construction of the balls 12 and 14 of the device 10 , the inner balls 22 and 24 comprise the major portions of the respective balls 12 and 14 . the balls 22 and 24 are solid spheres and preferably may be molded of a soft plastic material such as closed microcellular polyurethane foam , and can have a density of one - half pound per cubic foot to five pounds per cubic foot , preferably one pound per cubic foot to 2 pounds per cubic foot , and most preferably one and one - half pounds per cubic foot . the outer coverings 32 and 34 are of a flexible material , such as rubber , leather or vinyl foam . preferably the coverings 32 and 34 are cast onto the respective inner balls 22 and 24 and are of a resilient form of closed cell foam ; alternatively the coverings may be produced by dip molding over a suitable mandrel and subsequently stretched over the inner balls 22 and 24 . each outer layer 32 and 34 is relatively thin as compared to the balls 22 and 24 , and an exemplary thickness is about one - sixteenth inch to one - fourth inch , preferably one eighth inch to three - sixteenths inch , and represents approximately three to five percent of the total thickness of the entire balls 12 and 14 . as noted earlier , the enlarged diameter confronting end portions 52 and 54 are provided to insure that there is suitable space between the balls so that the apex or circumferential areas thereof contact the facet joints , and to reduce the depth ( toward the shaft 16 ) between the balls . for example , the apex areas identified as &# 34 ; a &# 34 ; of each of the balls 12 and 14 and which forms the principal portions thereof which contact the person being treated have a diameter of approximately three and one - half inches and are spaced approximately two to six inches apart , and preferably are about three and one - fourth inches to four inches apart for the general population . for small persons who do not fit the size parameters of the general population , especially dimensioned and spaced balls may be provided . it is believed that the spherical to elliptical configuration shown in fig1 and 2 is the most preferred configuration inasmuch as narrow disc shaped devices such as shown in the gromala patent are believed to present a harsh or dangerously small contact area with the potential for substantial bruising of the muscles . on the other hand , while a flattened &# 34 ; rolling pin &# 34 ; shape provides the maximum contact area and may provide maximum safety as in the simmons patent , it cannot sufficiently penetrate to manipulate or mobilize the intervertebral joints and facet joints of the spine . thus , the spherical shape of the principal contact areas provided by the balls 12 and 14 , along with the diameter of confronting inner portions 52 and 54 which results in what is termed herein a &# 34 ; spherical to elliptical &# 34 ; shape is believed to be a significant improvement over devices of the prior art . fig8 through 11 illustrate an alternate embodiment of a spinal and soft tissue mobilizer according to the present invention . as will be apparent from these figures and the following discussion , the major differences are that the balls in this embodiment have a substantially spherical or elliptical cross section and comprise relatively hard inner balls formed of metal , wood or hard plastic , and an outer resilient cover of a soft material such as silicone . while the construction is useful and desirable , it has higher manufacturing costs than the first embodiment of fig1 - 3 . the device 80 shown in fig8 through 11 comprises a pair of spherical or elliptical cross section balls 82 and 84 suitably mounted on a shaft 85 and provided with handles 81 and 83 . the balls 82 and 84 comprise inner and relatively hard solid spherical balls 86 and 88 respectively , mounted on the shaft 85 via cylindrical sleeves 90 and 92 . outer resilient covers 94 and 96 are provided on the respective balls 86 and 88 . the ends of the shaft 85 are provided with the handles 81 and 83 in the form of rubber handles for comfort of the operator . in this embodiment , the inner ends of the sleeves 90 and 92 abut at 98 , and are retained confronting by means of c - clips 100 and 101 ( note in particular fig1 ) or other suitable means at the outer ends of the respective sleeves 90 and 92 . the sleeves 90 and 92 extend completely through the balls 82 and 84 and , thus , extend completely through the spherical inner balls 86 and 88 and the respective resilient covers 94 and 96 , and thus the sleeves 90 and 92 act as sleeve bearings between the balls 82 and 84 and the shaft 85 . this allows the balls 82 and 84 to rotate freely and independently on the shaft 85 as in the first embodiment . while the sleeves 90 and 92 are shown as separate members from the balls 82 and 84 , they can be formed integrally therewith , such as being formed integrally with the inner balls 86 and 88 . as can be seen , particularly from fig9 and 10 , the soft outer coverings 94 and 96 surround the concentrically located inner balls 86 and 88 . the outer covers 94 and 96 are composed of synthetic rubber , and preferably they are formed of silicone . alternatively , a vinyl or urethane rubber can be used for the coverings 94 and 96 . the purpose of the outer covers 94 and 96 is to provide resilient coverings which are soft enough so that the spine is not bruised during treatment . an example hardness or durometer rating for the coverings 94 and 96 preferably ranges from shore a - 5 to a - 30 , preferably from a - 10 to a - 20 . it has been found that generally shore a - 31 is too hard and a - 4 is too soft . it is important that the balls 82 and 84 be sufficiently resistant so that they can effectively pressurize and mobilize the spine , yet be sufficiently elastic and soft so that bone bruising is minimized . as noted earlier , the inner balls 86 and 88 can be made of hard material , such as metal , wood or hard plastic . for example , a hard polyurethane is suitable , as is an acetal plastic sold under the trademark delrin . the hard inner balls need not be of solid cross section , but they may be composed of closely spaced ribs or posts approximately of a ball shape if preferred for molding reasons . the sleeves 90 and 92 act as bearings with respect to the shaft 85 for rotation of the balls 82 and 84 , but if a sufficiently hard material is used for the balls 86 and 88 , separate sleeves 90 and 92 can be omitted . the sleeves , if used , preferably are formed of a hard plastic , such as polyethylene , and it is desirable that the same have a low coefficient of friction with respect to the material of the shaft 85 . the shaft 85 can be composed of any suitable material , such as aluminum , steel , wood or plastic . aluminum is preferable , because of its lightness and stiffness , but steel tubing is less expensive . with respect to exemplary sizes , the balls 82 and 84 preferably have a diameter of one and one - half inches to three and one - half inches , and preferably about three inches . a three inch diameter ball is small enough to suitably work the muscles on either side of the spine , but large enough to provide knuckle clearance for the fingers of the operator around the handles 81 and 83 . as is the case with the embodiment of fig1 the balls 82 and 84 are spaced apart sufficiently so that both sides of the spine can be worked simultaneously . a spacing between the apexes &# 34 ; a &# 34 ; preferably is the same as that for the fig1 embodiment , namely preferably three and one - half inches to four inches ( or likewise measured between the centers of each of the balls 82 and 84 ). the size of the inner balls 86 and 88 depends on the desired outside diameter of the balls 82 and 84 , but typically the diameter of each of the inner balls 86 and 88 is one and one - half inch . the outer covers 94 and 96 typically are one half to three - fourths inch thick . the device 80 is used in the same manner as the device 10 of fig1 . in the case of use by a therapist or another person as illustrated in fig4 the patient is simply placed on his or her stomach , and the therapist or other person rolls the device 80 along the patient &# 39 ; s back along the spine . the balls 82 and 84 are placed about the spinal area so that both sides of the spine are worked simultaneously . the total force used is determined by the amount of weight applied to the handles 81 and 83 . similarly , the patient may place the device on the floor as shown in fig5 or against a wall as shown in fig6 to effectuate the rolling action and consequent mobilization . the outer covers 94 and 96 of the balls 82 and 84 are compressed during the rolling action . however , the degree of compression is still limited by the inner hard balls 86 and 88 , resulting in an effective treatment which does not bruise the patient and which is somewhat comparable to the cushioned pressure provided by the heel of the human hand but with a stretching and rolling action which is difficult to produce with the hand alone . while embodiments of the present invention have been shown and described , various modifications may be made without departing from the scope of the present invention , and all such modifications and equivalents are intended to be covered .
a therapeutic device to mobilize the spinal joints and soft tissues surrounding the human spine . the device includes two substantially solid spherical balls mounted on a shaft for independent rotation . in one embodiment , the balls have a spherical to elliptical configuration and comprise an inner ball portion of a variable density synthetic plastic material and with an outer covering or portion comprised of a flexible material . the balls have a confronting area forming a substantially elliptical shape extending from a major spherical ball portion . another embodiment comprises two spherical rubber balls having an inner ball formed of hard material to assist in the mobilizing operation and an outer flexible rubber cover . in either embodiment , the balls may be mounted on the shaft via suitable sleeves disposed through the inner ball portions . the device may be used in self - treatment or may be applied by another person .