GB2113107A - Anatomically manipulable rotatable implement - Google Patents

Abstract

An anatomically manipulable toy (10) in the form of a rotatable implement comprises a shaft (12), a massive body portion (14,15,17) rigidly attached to the shaft (12), and a contant element (13) at one end of the shaft (12). In operation, the rotating implement (10) is spun and then supported by placing the contact element (13) on a portion of the user's anatomy, typically a hand, with the shaft (12) horizontal. The contact element (13) rolls on the user's anatomy, thereby producing a linear translation therealong. The weight of the implement (10) acts at a position horizontally separated from the point of contact and causes a precession of the spinning implement (10) about the vertical axis through the point of contact. The rate of precession depends on the rate of angular rotation and the distance of horizontal separation, <IMAGE>

Description

SPECIFICATION Anatomically manipulable rotatable implement The present invention relates generally to toys, and more specifically to the type of toy having an operation whose complexity and duration depend on the adroitness of the user.

Rotating objects have fascinated countless generations of children and adults, and one need not look far in the art to find numerous examples of toys whose operation incorporates a rotating element.

The top, the flying saucer, the hula-hoop, and the yo-yo are but a few examples of such toys.

The key to a toy's long-term success is its ability to maintain the interest of the user as the user's dexterity and skill improve. This in effect presents a dual requirement on the toy. Unless a beginner can quickly master the rudiments of the toy's operation, he is likely to become discouraged and abandon efforts to perfect his skill. In such a case, the toy can scarcely be said to have universal appeal.

Conversely, a toy that is capable of a limited number of manoeuvres, or perhaps only simple manoeuvres, fails to hold the interest of a user for more than a short period of time. To some extent, skill is correlated with age, and the most appealing toy is one that is capable of gratifying and challenging users of all ages. Every year, while numerous new toys enter the marketplace, the number of toys that have long-term appeal to people over a wide age range remains surprisingly small.

The present invention provides a anatomically manipulable toy that requires relatively little dexterity for initial use and mediocre coordination for execution of fundamental skills, but that elicits continued development of dexterity for progressive proficiency of operation. Once the basic skills are mastered, the present invention continues to challenge the imagination of the creative, the coordination of the dexterous, and the finesse of the graceful.

Broadly, the present invention provides a rotatable implement comprising a shaft, a massive body portion rigidly attached to the shaft, and a contact element at one end of the shaft. The body portion typically assumes the configuration of a generally circular plate-like element or spoked wheel. The contact element typically has cylindrical symmetry about the shaft and, depending on the shaft diameter, may be defined solely by the shaft and itself. In operation, the rotating implement is generally supported by placing the contact element on a portion of the user's anatomy, typically a hand, with the shaft horizontal, rotation having been initiated by manually imparting a torque to the implement, typically at the shaft. The contact element rolls on the user's anatomy, thereby producing a linear translation therealong.The weight of the implement acting at a horizontal separation from the point of contact causes a precession of the spinning implement about the vertical axis through the point of contact. The rate of precession depends on the rate of angular rotation and the distance of horizontal separation. Thus, the rotating implement precesses at a controllable rate relative to the rate of linear translation, allowing the implement to circumscribe a portion of the anatomy such as the palm or travel along the arm as the user rotates the arm.

The dimensions and mass distribution of the device are characterised by three dimensional parameters, namely the radius of gyration (defined primarily by the mass distribution of the body portion), the axial distance between the centre of gravity of the device and the point of contact between the contact element and the user's anatomy, and the diameter of the contact element. These dimensions will be referred to as R. L, and D, respectively.

During operation of the device, the motion is characterised by three kinematic quantities, namely the angular velocity of the device about the shaft axis, the precessional angular velocity about a vertical axis, and the translational velocity of the contact element rolling on the user's anatomy. These quantities are referred to as a), Q, and v, respectively. These kinematic quantities are not independent, but are related by the dimensional parameters and the laws of physics governing precession of rigid bodies. As will be seen in greater detail below, these relationships plus certain human body dimensions place effective constraints on these parameters.For example, the quantity L/(R2D) is preferably in the range of 0.05-0.11 reciprocal inches squared (hereinafter sometimes inch2) (0.00775-0.01705 cm-2).

Within the dimensional constraints, dictated largely by a desire to avoid unduly strenuous operation, the device may be constructed in any chosen manner. For example, the body portion may assume the form of a spoked wheel integrally fabricated from plastic and having a central aperture for accommodating the shaft. The contact element may be integrally formed with the shaft, but is preferably detachable therefrom, and may be fabricated from semi-soft rubber or the like.

In addition to manoeuvres wherein the shaft-end element is in continuous contact with the user's anatomy, as for example where the shaft-end element circumscribes a hand of the user, the device is capable of being used to execute flight manoeuvres. Tossing the implement is generally effected while maintaining the axis of rotation substantially horizontal, and is accomplished by partially closing the fingers of one hand around the shaft of the rapidly rotating implement, accelerating the forearm in the intended direction of flight so that the loosely constrained implement is propelled therewith, and releasing the shaft to project the implement.Catching the rotating implement is accompiished by placing some part of the anatomy underneath the contact element of the flying implement, and moving that part of the anatomy with the implement in the direction of flight to gradually reduce linear velocity without appreciably retarding the rotational velocity.

Thus it can be seen that the present invention provides a surprisingly simple and inexpensive toy that is capable of a great variety of manoeuvres and operations and which provides a user with an immediate and continuing challenge. For a further understanding of the nature and advantages of the present invention, embodiments thereof will now be described with reference to the accompanying drawings in which: Fig. 1 is a perspective view of an implement according to the present invention, Fig. 2 is a perspective view of an alternate embodiment, Figs. 3a-3g are sequential views illustrating a typical manoeuvre by a user, and Fig. 4 is a plan view of the user's hand showing schematically the locations of the implement in the positions illustrated in Figs. 3a-3g.

Referring now to Fig. 1 there is shown an implement 10 which comprises a shaft 12, a massive body mounted on the shaft, and a contact element 13 on one end of the shaft. In this embodiment, the massive body assumes the form of a wheel having a hub 14 mounted on shaft 12, an outer rim 15, and a plurality of radially extending spokes 1 7 connecting hub 14 and rim 1 5 in a coaxial arrangement.

Contact element 1 3 is preferably a frusto-conical bushing at an end of shaft 12 displaced from hub 14.

Shaft 1 2 preferably extends completely through hub 14 and carries a second contact element 23 at its other end. Shaft 1 2 is preferably a relatively thin cylindrical rod formed from a rigid high strength material such as steel with a relatively low coefficient of friction. Contact elements 1 3 and 23 are preferably formed from a somewhat resilient material of relatively high coefficient of friction such as semi-soft rubber. Hub 14, rim 1 5, and spokes 1 7 are preferably formed integrally from a plastic material such as polystyrene or polypropylene. Hub 1 4 and contact elements 13 and 23 are fixedly mounted to shaft 12 so that relative rotation is avoided, but contact elements 13 and 23 may be made removable.

As is described in detail below, operation of implement 10 involves a rotation about the axis of shaft 12 with contact element 13 contacting a portion of the user's anatomy and rolling therealong.

This rotation, acted upon by a gravitational torque, causes implement 10 to precess about a vertical axis. Three dimensional variables determine the nature of the overall motion. The first dimensional variable is the radius of gyration, designated R, that is a function of the geometry and mass distribution of implement 10. Generally, it is preferred to have as much mass as possible at radially outermost portions to get as large a radius of gyration as possible for a given overall size of implement 10. For the configuration shown, a sizable fraction of the mass is concentrated at rim 1 5 so that the radius of gyration does not differ appreciably from the geometric radius of rim 1 5. The second dimensional variable is the diameter 25, designated D, of contact element 13 at the point where it contacts the user.The third dimensional variable is the distance 27 (moment arm), designated L, from the centre of mass of implement 10 to the point of contact between contact element 1 3 and the user. Generally, for a symmetric implement operated with the shaft horizontal, this will be the distance from the medial plane to the outer axial surface of contact element 13.

Fig. 2 shows an alternate embodiment of an implement 30 according to the present invention includiny a mass 31 affixed to a shaft 32 having an end 35. This embodiment differs from the embodiment of Fig. 1 in two respects. First, mass 31 has a decidedly non-circular configuration.

Second, shaft 32 is devoid of any separate contact member such as contact element 1 3 so that end 35 defines the contact element. The comments that follow are made with reference to illustrations in which the embodiment of Fig. 1 is shown. However, it should be understood that a wide variety of geometrical configurations will be suitable. As is developed below, the dimensional parameters R, D and L are preferably constrained to certain internal relationships in order to allow a user to execute manoeuvres.

Figs. 3a-3g are sequential views showing positions that are assumed as a user 40 executes a manoeuvre during which contact element 22 of device 1 0 rolls along the periphery of the palm side of the user's left hand 42. Figs. 3a-3g should be viewed in connection with Fig. 4 which is a plan view of left hand 42 of user 40 in which the successive positions of contact element 22 relative to hand 42 are shown in phantom. Hand 42 includes a palm 45, an index finger 46, a thumb 47, a little finger 48, and intermediate fingers 49. Palm 45 is partly bounded by an edge 50 remote from thumb 47 and generally collinear with little finger 48, and a heel portion 52 proximate the user's wrist. It should be noted that throughout this manoeuvre, hand 42 is not stationary, but rather rotates in a clockwise manner (looking from above).The manoeuvre is carried out with implement 10 rotating about a generally horizontal axis such that the gravitational torque caused by the displacement of the centre of gravity from the point of support (that is, due to moment arm 27) causes the overall clockwise (looking from above) precession of implement 10 about a vertical axis. Hand 42 is at times rotated more quickly than the precession so that a relative counter-clockwise movement of implement 10 occurs.

Referring to Fig. 3a, left hand 42 is in a generally open position with contact element 1 3 located at a position along palm edge 50 proximate heel 52. Palm 50 faces upward and the fingers are directed away from user 40. As implement 10 rolls towards the little finger 48, the precession causes it to veer to the right, necessitating a concurrent clockwise rotation of hand 42 to continue supporting the implement. Thus, as can be seen in Figs. 3b and 3c, as contact element 1 3 rolls along the edge 50 of palm 45 onto little finger 48, a precession of approximately 900 has occurred, thereby necessitating a corresponding 900 rotation inward of left hand 42.

User 40 then causes left hand 42 to rotate faster than the precessional angular velocity so that contact element 1 3 rolls over intermediate fingers 49, finally assuming a position on index finger 46 as shown in Fig. 3d. Referring to Fig. 3e, user 40 then places thumb 47 on contact element 13 and rotates hand 42 from the wrist 1 800 upward in order to transfer contact element 13 from index finger 46 to thumb 47. With reference to Fig. 3f, it can be seen that palm 45 is still facing generally upward, but with the fingers pointing generally back toward user 40. Implement 10 then rolls down the thumb and across heel 52 of hand 42, as shown in Fig. 3g. It will be appreciated that in the position shown in Fig.

3g, implement 10 is approaching the initial position of Fig. 3a except that the user's hand is in an elevated position. User 40 may then lower hand 42, thereby returning to the initial position of Fig. 3a.

A further manoeuvre, not illustrated, involves movement along a user's right arm. During this manoeuvre, the user maintains his palm facing upward and initially supports contact element 1 3 or 22 so that rotation of implement 10 causes contact element 13 or 22 to roll toward the right elbow along the left side of the right forearm. The elbow is initially bent. The rolling causes a clockwise precession which must be accompanied by a corresponding clockwise rotation (as viewed from above) of the forearm in order that implement 10 roll uniformly along the forearm. Thus, by the time implement 10 has travelled approximately halfway along the forearm, the forearm must have pivoted approximately 900 clockwise from the elbow in order to maintain support.Initially the right arm is bent at a 900 angle so that the 900 bend from the elbow generally straightens the arm out. A further 900 rotation of the entire arm from the shoulder occurs to that the forearm has pivoted a total of 1 800 concurrently with a 1 800 precession of the axis of rotation. During this time, contact element 13 or 22 will have rolled generally from the little finger to a position proximate the elbow (approximately 20 inches) (50.8 cm).

During operation of implement 10, as exemplified by the above described manoeuvres, the motion is characterised by three kinematic quantities of interest, namely the angular velocity of implement 10 about the axis of shaft 12, the precessional angular velocity about a vertical axis, and the translational velocity of contact element 1 3 or 22 as it rolls along an appropriate portion of the user's anatomy. These quantities are referred to as o, Q, and v, respectively. As is shown below, these kinematic quantities are not independent, but are related by the dimensional parameters R, L, and D, and the laws of physics governing rotational motion of rigid bodies.In particular, it may be shown that when implement 10 is rotating at angular velocity c9 about a horizontal axis, the weight of implement 10 acting at a distance L from the point of support causes a precession about a vertical axis with the precessional angular velocity Q given by: gL (Eqn. 1) Fit20 where g is the acceleration of gravity.

The rotation of implement 10 about the shaft axis is related to the linear movement of contact element 22 by the constraint that contact element 22 rolls without slipping so that: a)D (Eqn. 2) 2 Dividing Eqn. 1 by Eqn. 2 and rearranging, leads to the following relationship: L 1 - (/v)a)2=k(/v)a)2 (Eqn. 3) R2D 29 where k=.0013 (.0005096) when all lengths are expressed in inches (cms) and angles in radians. This equation is interesting since the lefthand side is an expression composed of dimensional variables only while the righthand side is an expression composed of kinematic quantities only. As will be now shown, certain constraints on these kinematic quantities lead to effective limits on the quantity L/(R2D).

Generally, implement 10 does not rotate more slowly than approximately one revolution/second because it would become unstable and difficult to control due to insufficient gyroscopic resistance.

Moreover, a rotational speed of more than five revolutions/second is unlikely because the user would become fatigued from having to impart such fast rotation. Thus, while rotational rates outside this range are possible, the most comfortable, easily obtainable, and useful range for a) appears to be from 1.5-4 revolutions/second, which is equivalent to approximately 9-25 radians/second.

Directly associated with the operation of implement 10 in accordance with the spirit of this invention is the ratio (Q/v) which gives the amount of angle precessed for a given distance travelled.

Throughout a manoeuvre, the location of contact element 13 on the user's body and the direction of the axis of shaft 12 relative to the coronal plane of the user must be properly coordinated in order for the user to be physically ablve to maintain continuously some part of his anatomy underneath and slightly in front of the rolling contact element without bumping against rim 1 5. In particular, experience has shown that practical and useful values for the abovementioned ratio appear to range from approximately 0.14-0.60 radians precessed per inch rolled (.055-236 radians per cm).For example, during the execution of the hand manoeuvres illustrated in Figs. 3a-3g, the axis of rotation precesses one rotation (approximately 6.28 radians) while contact element 13 rolls approximately 13 inches (33 cms), corresponding to approximately 0.5 radians/inch (.19 radians per cm). During the execution of the arm manoeuvre described briefly above, the axis of rotation precesses approximately 1 SOC (3.14 radians) while contact element 13 rolls approximately 20 inches (50.8 cm), corresponding to 0.16 radians/inch (.0618 radians/cm).

Equation 3 can be rearranged so that the ratio (,v of angle precessed for distance rolled is given in terms of the other variables. In particular, 2gL 1 (#/v)= (Eqn.4) R2D ,2 Therefore, it can be seen that the ratio is inversely proportional to the square of the rotational velocity , so that the user is able to control the ratio by controlling the rotational velocity-increasing the rotational velocity decreases the amount of precession per distance rolled and vice versa.

Table 1 shows values for the quantity k (Q/V)CI)2 when (v) and a) vary over the approximate ranges described above. Although the values for (Q/v) and can change from one manoeuvre to another and even during a particular manoeuvre, the value of k (/v)a)2 remains relatively constant because the physical dimensions of an integrally rigid implement do not ordinarily vary appreciably.

Table 1 Values for k (/v)a)2 in inch-2), a) in radians per second 9 11 13 15 17 19 21 23 (v) in radians per inch 1/2 .05 .08 .11 .15 .19 .23 .29 .34 1/3 .04 .05 .07 .10 .13 .16 .19 .23 1/4 .03 .04 .05 .07 .09 .12 .14 .17 1/5 .02 .03 .04 .06 .08 .10 .11 .13 1/6 .02 .03 .04 .05 .06 .08 .10 .11 1/7 .01 .02 .03 .04 .05 .07 .08 .10 Table 2 Values for k (/v)2 in cms2, c,) in radians per second 9 11 13 15 17 19 21 23 (v) in radians per cm .197 .008 .012 .017 .023 .029 .036 .045 .053 .131 .006 .008 .011 .016 .020 .025 .029 .036 .098 .005 .006 .008 .011 .014 .019 .022 .026 .079 .003 .005 .006 .009 .012 .016 .017 .020 .066 .003 .005 .006 .008 .009 .012 .016 .017 .056 .002 .003 .005 .006 .008 .011 .012 .016 An analysis of Table 1 reveals that the complete ranges of (Q/v) and a) cannot be simultaneously achieved, but that generally a major part of each range will be available to the user when the quantity k (Q/v)c1)2 lies in the range approximately 0.05--0.1 1 inch-2(.00775--.017 cms-2). An intermediate value within this range, namely 0.08 inch-2 (.0124 cm-2) is typicai and affords substantially the entire ranges of kinematic variables of interest.

Practical considerations also put constraints on the values of the dimensional variables L, R, and D.

A lower limit on the value of the moment arm, L, arises from the nature of certain manoeuvres.

The user, trying to continuously position some part of his anatomy underneath the rolling contact element, frequently has to pivot that part of his anatomy about the point of support of the contact element. In order to effect such a pivot without bumping against the rotating mass, the contact element must project outwardly from the implement at least a distance of approximately 1 inch (2.54 cm). Furthermore, ease in pivoting requires an outward projection of at least half the distance across the user's palm, which will depend somewhat on the size of the user. An upper limit of the value of moment arm L arises during some manoeuvres which require the user to change the point of support of from the distal end of the shaft to a point adjacent the mass.This change becomes increasingly difficult as the length of the moment arm exceeds approximately 4 inches (10.1 6 cm). A range of approximately 1.5-3 inches (3.81-7.62 cm) for L is reasonable.

Notice that a change in the point of support of the shaft assembly changes the rate of precession without altering the rotational velocity. Many manoeuvres require the user to support the distal end of the shaft assembly. Increasing the length of the shaft assembly increases the rate of precession, which rate needs to remain within the aforementioned range. Although the effect caused by increasing the length of the shaft assembly can be compensated for by increasing the radius of gyration, many manoeuvres involve passing the implement under the arm and thus requires that the overall radius of implement 10 be significantly less than the length of the user's arm. Thus, the radius of gyration R must be even less than this.An overall range of approximately 3-1 3 inches (7.62-33 cm) is feasible, with 5-9 inches (12.7--22.86 cm) being preferred.

Table 2 shows the values of the diameter D of contact element 13 for values of R and L lying in the abovementioned ranges and wherein the value of V(R2D) equals 0.08 inch-2 (.0124 cm-2).

Table2 Values for D in inches satisfying the equation .08=i/(R2D) Radius of gyration R in inches 3 5 7 9 11 13 Moment arm L in inches 1 1.4 .5 .26 .15 .10 .08 1.5 2.1 .75 .38 .23 .15 .11 2 2.8 1.0 .51 .31 .21 .13 2.5 3.5 1.25 .64 .39 .26 .19 3 4.2 1.5 .77 .46 .31 .22 3.5 4.9 1.75 .89 .54 .36 .25 4 5.6 2 1.02 .61 .41 .31 Table 2 Values for D in cms satisfying the equation .01 24=L/(R2D) Radius of gyration R in cms 7.62 12.70 17.78 22.86 27.94 33.00 Moment arm L in cms 2.54 3.56 1.27 0.66 0.38 0.25 0.20 3.81 5.33 1.91 0.97 0.58 0.38 0.28 5.08 7.11 2.54 1.30 0.79 0.53 0.33 6.35 8.89 3.18 1.63 0.99 0.66 0.48 7.62 10.67 3.81 1.96 1.17 0.79 0.56 8.89 12.47 4.45 2.26 1.37 0.91 0.64 10.16 14.22 5.08 2.59 1.55 1.04 0.79 Inspection of the values in Table 2 indicate that values for D lie in the range of 0.08-5.6 inches (.203-1 4.224 cm). However, a narrower range of values D arises from the need to maintain the linear velocity v within reasonable limits. In particular, rates of linear movement less than approximately 1 inch/second (2.54 cm/sec) are possible but tend to draw manoeuvres out for an unduly long time. Such longer periods of time between occasional accelerations cause implement 10 to lose momentum and stability. As the linear velocity increases beyond approximately 12 inches/second (30.48 cm/sec), manoeuvres become increasingly difficult to execute gracefully and require progressively greater dexterity for proficiency of operation.In order than the linear velocity remain below approximately 12 inches/second (30.48 cm/sec) when the angular velocity a) is as high as 23 radians/second, the diameter D must be less than approximately 1.05 inches (2.667 cm). Similarly, in order than the linear velocity remain above approximately 1 inch/second (2.54 cm/sec) when the angular velocity Q drops as low as 9 radians/second, the diameter D must be above approximately 0.22 inches (.5588 cm). A more practical range is approximately 3/8-1 inch (.953-2.54 cm), which values lie within the dashed outline in Table 2.

Although the actual mass of implement 10 does not enter into the equations and constraints discussed above, practical consideratione dictate a range of 3-12 ounces (93.3-373.2 grm). The lower end of the range arises from manufacturing and stability factors; the upper end arises from considerations of avoiding user fatigue.

In summary, it can be seen that the present invention provides an anatomically manipulable toy whose operation combined with anatomical considerations determines a number of dimensional ranges. While two exemplary manoeuvres have been described, the number of manoeuvres possible with such an implement is bounded only by the user's imagination.

While the above provides a full and complete disclosure of the preferred embodiments of the invention, various modifications, alternate constructions, and equivalents may be employed without departing from the true spirit and scope of the invention. For example, contact elements 13, 22 and 23 were assumed to be of equal size. This is not necessary, since the provision of contact elements of differing sizes on the same implement would allow a greater dynamic range of operation. Similarly, each individual contact element need not have a single well-defined diameter for contacting the user.

Rather, more complex longitudinal sections could permit different contact diameters depending on the precise point of contact. Therefore, the above description and illustrations should not be construed as limiting the scope of the invention which is defined by the appended claims.

Claims (14)

Claims

1. A manually rotatable, anatomically manipulable and supportable implement comprising rigid body means defining a radius of gyration about an axis and being characterised by a centre of gravity; frictional contact means for providing a point of support of said rigid body means, said contact means defining a rolling diameter D centred about said axis; and means for rigidly spacing said point of support from said centre of gravity along said axis to define a distance L; said implement being configured for executed manoeuvres wherein said contact means undergoes rolling motion along an anatomical portion of the user, the overall dimensions of said implement and the dimensional parameters R, D, and L being sized such that the rotational velocity of said implement about said axis, and the gravitational torque acting on said centre of gravity about said point of support causes a precessional velocity that permits said user to maintain some anatomical portion underneath said rolling contact means without bumping against said body means for prolonged lengths and duration as said axis is maintained in a generally horizontal orientation, said dimensional parameters being further interrelated to permit said manoeuvres to be carried out over a substantial range of kinematic variables.

2. A manually rotatable, anatomically manipulable and supportable implement comprising rigid body means defining a radius of gyration R about an axis and being characterised by a centre of gravity; contact means for providing a point of support of said rigid body means on a portion of a user's anatomy, said contact means defining a rolling diameter D centred about said axis; and means for rigidly spacing said point of support from said centre of gravity along said axis to define a distance L; the overall dimensions of said implement and the dimensional parameters R, L, and D being sized to permit the user to execute manoeuvres wherein said contact means undergoes rolling motion long an anatomical portion of said user whilst the gravitational torque acting about said centre of gravity causes a precessional velocity that correlates with said rolling motion to permit said user to maintain some anatomical portion underneath said rolling contact means for significant precessional rotation without bumping against portions of said body means, and wherein said length L divided by the product of said diameter D and the square of said radius of gyration R is in the range of approximately 0.05 to 0.11 reciprocal inches squared (0.00775-0.01705 cm~2) to permit said manoeuvres to be carried out over a substantial range of kinematic variables.

3. The invention of Claim 1 wherein said length L divided by the product of said diameter D and the square of said radius of gyration R is in the range of approximately 0.05 to 0.11 reciprocal inches squared, (0.00775-0.01 705 cm-2).

4. The invention of Claim 2 or 3 wherein R is in the range of 5-9 inches (12.7-22.86 cm), D is in the range 3/8-1 inch (0.953-2.54cm) and L is in the range 1.5-3 inches, (3.81-7.62 cm).

5. The invention of Claim 1 or 2 wherein said radius of gyration is primarily defined by a wheellike body member, and wherein said length L is primarily defined by a relatively small diameter shaft passing through the centre of said body member.

6. The invention of Claim 5 wherein said contact means is defined by a bushing of diameter D mounted coaxially to an end of said shaft.

7. The invention of Claim 5 wherein said shaft has a diameter D at an end Thereof to define said contact means.

8. The invention of Claim 4 wherein said implement has a weight in the range of 3-12 ounces, (933-373.2 grm).

9. An anatomically manipulable toy comprising a rigid shaft; a mass rigidly mounted to said shaft and extending radially outward therefrom; and a generally cylindrical symmetric end element mounted proximate an end of said shaft coaxially therewith to provide a point of rolling contact with a portion of a user's anatomy as said toy undergoes translational, rotational, and precessional motion; said toy being characterised by the dimensional parameters R, L and D where R is the radius of gyration of said toy about the axis of said shaft, L is the distance between the centre of gravity of said toy and the point of contact between said user and said shaft end element, and D is the diameter of said end element, the overall dimensions of said toy and said parameters R, L and D being sized to permit the user to execute manoeuvres wherein said end element undergoes a rolling motion along an anatomical portion of said user whilst the gravitational torque acting about said point of contact causes a precessional velocity that correlates with said rolling motion to permit said user to maintain some anatomical portion underneath said rolling end element for significant precessional rotation without bumping against portions of said mass, and wherein L/R2D in the range 0.05-0.11 inches-2 (0.0075- 0.01705 cm-2) to permit said manoeuvres to be carried out over a substantial range of kinematic variables.

1 0. The invention of Claim 9 wherein said mass has a wheel-like configuration coaxial about said shaft.

11. The invention of Claim 9 wherein said shaft end element is removably secured to said shaft and is fabricated from a somewhat resilient frictional material.

12. The invention of Claim 9 wherein said mass is mounted to an intermediate portion of said shaft so that said shaft extends away from said mass in both directions.

13. The invention of Claim 9 wherein R is in the range of 5-9 inches (12.7-22.86 cm), D is in the range of 3/8-1 inch (0.953-2.54 cm), and L is in the range of 1.5-3 inches (3.81-7.62 cm).

14. An anatomically manipulable rotatable implement substantially as hereinbefore described with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawings..