AU755687B2 - Improvements in yo-yos - Google Patents

Description

WO 99/03547 PCT/AU98/00545 -1- IMPROVEMENTS IN YO-YOS Field Of The Invention This invention relates to improvements in yo-yos and an improved automatically returning yo-yo.

Background Of The Invention Yo-yo players, especially beginners, have been assisted by the development of yo-yos provided with a means to automatically return the yo-yo to the player's hand before the yo-yo spins out completely. Such an invention is described in U.S. Patent No. 4332102 (Caffrey June 1 1982).

The Caffrey invention employs a rotatable bearing pulley mounted on the axle to which the yo-yo string is attached. Adjacent the pulley section of the bearing is provided a cylindrical friction or braking means that interacts with two clutch mechanisms. The surface of the friction or braking means has characteristics of resistance to slip, and is in practice one or a series of O-rings, which are subject to wear. The clutch mechanism is provided with weighting means such that when the yo-yo is thrown the clutch is released by the development of centrifugal forces. The centrifugal force is counter-balanced by a spring loaded force such that the clutch is activated when the yoyo slows down. The clutch engages the cylindrical friction surface of the pulley extension while the yo-yo still has sufficient momentum to enable the automatic return of the yo-yo to the player's hand. The successful development of an automatically returning yo-yo has proven to be especially valuable to beginners. It is also viewed as a valuable assistance to less gifted or handicapped players.

The nature of the Caffrey invention, however, critically weakens the structural integrity of the yo-yo. In order for the pulley bearing to be accessable to the clutch mechanism housed within a yo-yo half requires part of the boss enclosing the axle to be removed in the plastic mould. To enable sufficient braking capacity to be applied, up to 80% of the plastic boss must be removed at the meeting place of the pulley extension friction surface and clutch mechanisms.

SUBSTITUTE SHEET (Rule 26) WO 99/03547 PCT/AU98/00545 -2- Because the pulley is also the string bearing means problems occur when bearing lubrication applied in excess finds its way with the aid of centrifugal forces to the nearby contact area between clutch and pulley such that the clutch slips and fails to return the yo-yo successfully.

The Caffrey invention, by linking the centrifugally operated clutch to a coaxial extension of the string bearing means, has intrinsically restricted options on varying the quality of the string bearing means. The use of a dual purpose bearing that combines a string securing means as well as a clutch interfacing means where the clutch means is operatively enclosed in the yo-yo half, must by nature expand laterally along the axial member to accommodate both functions. A superior spinning automatically returning yo-yo is achieved by narrowing the string bearing means thereby reducing the area frictionally contacting the axial member. Having the centrifugally activated clutch operatively engage an integral extension of the string bearing means also necessitates the use of double-loop string attachment to inhibit the string from slipping on the bearing means and thereby reducing the clutch effectiveness. The general. public have difficulty in tying a double-loop attachment.

Also, in a commercial form of the Caffrey invention, the clutch mechanism is supplied in only one yo-yo half, which creates a weight differential in the two yo-yo halves that is believed to shorten the free spinning time of that invention.

Another problem experienced with an automatically returning yo-yo that has a static spacing between yo-yo halves is that different yo-yo manoeuvres, to be performed efficiently, require different yo-yo response tolerances. Tom Kuhn in his publication "SB2 Flight Manual" in "The art of yo-yo choreography", indicates a narrower string gap is better for loop-the-loops and a wider string gap is better for complex spin tricks.

It is a first primary objective of the present invention to provide improved means of automatically returning the yo-yo.

It is a second primary objective of the present invention to improve the structural integrity and ease of maintenance of an automatically returning yo-yo.

It is a third primary objective of the present invention to improve the free-spinning time of an Q:\OPER\GCP820I 2c.doc- 18/0800 -3automatically returning yo-yo.

it is a fourth primary objective of the present invention to improve the loop-the-loop characteristics of an automatically returning yo-yo without sacrificing superior performance in free-spinning time.

It is a fifth primary objective of the present invention to accommodate the natural progression of the operator's skills by allowing the removal of the automatic returning mechanism and conversion of the yo-yo to a conventional yo-yo with multi optional performance spinning characteristics by allowing the selective use of string bearing means of various compositions and properties.

0. 0 It is a sixth primary objective of the present invention to optionally provide an automatically returning yo-yo requiring only single-loop string attachment.

o*oo. Summary of the Invention According to the present invention there is provided an automatically returning yo-yo comprising: 00o0 20 a first rotatable yo-yo half; a 00 0 a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and defining an axis of rotation about which said yo-yo halves can rotate; a string having one end connected to said axle-assembly between said yo-yo halves; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one engagement-member disposed for substantially linear movement in a direction which is at least substantially parallel to said rotation axis, Rthe linear position of said engagement-member being dependent on the rotational 7 velocity of said clutch; and Q:\OPER\GCP\82012c.dc- 18/08/00 -4at least one biasing member for resiliently urging said engagement-member into engagement with a portion of at least one of said string and said axle-assembly when the rotational velocity of said clutch is below a predetermined value.

The invention also provides a yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; means for mechanically coupling said first and second yo-yo halves and for defining an axis of rotation about which said yo-yo halves can rotate; a string having ends, one of said string ends being connected to said means for mechanically coupling at a point thereof which is between said yo-yo halves; and of centrifugally-activated clutch means for translating centrifugal forces of at least one of said yo-yo halves in a first plane into linearly-directed forces in a second plane which intersects said first plain; said clutch means includes at least one engagement-member disposed for substantially linear movement within said second plane.

The invention also provides an automatically returning yo-yo comprising: o: a first rotatable yo-yo half; •ga second rotatable yo-yo half; 20 an axle-assembly mechanically coupling said first and second yo-yo halves and go defining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly comprising a string bearing member and an axle which is stationary relative to at least one ol".1of said yo-yo halves, said string bearing member having at least one braking surface, being mounted on said axle and being freely rotatable thereto; a string having one end connected to said string bearing member between said yo-yo halves; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one engagement member disposed for substantially linear movement 30 in a direction which is at least substantially parallelto said rotation axis, the linear Q:\OPER\GCP 8202c.doc-1lO8/08/00 -4Aposition of said engagement member being dependent on the rotational velocity of said clutch; and at least one biasing member for resiliently urging said engagement member into engagement with at least one of said string and said braking surface when the rotational velocity of said clutch is below a predetermined value.

The invention also provides an automatically returning yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and defining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly having an axle and a string bearing member mounted on and freely rotatable relative to said axle; a string having one end connected to said string bearing member; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one engagement-member disposed for substantially linear movement in a direction which is at least substantially parallel to said rotation axis, the linear position of said engagement member being dependent on the rotational 20 velocity of said clutch; and at least one biasing member for resiliently urging said engagement member into engagement with said string when the rotational velocity of said clutch is below a predetermined value.

The invention also provides an automatically returning yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and defining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly 0 having an axle; a string having one end connected to said axle-assembly with a single-loop string QAOPER\GCP\82012c.doc-18/0 0 -4Battachment; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one movable engagement member wherein the position of said engagement member is dependent on the rotational velocity of said clutch; and at least one biasing member for resiliently urging said engagement member into engagement with said string when the rotational velocity of said clutch is below a predetermined value; said engagement member is disposed for substantially linear movement along, and acts symmetrically about, said rotation axis.

o* a e *a e WO 99/03547 PCT/AU98/00545 Throughout the present specification ,the term effective centripetal force is understood to be a force that comes into play in the absence of a superior centrifugal force or which overcomes a centrifugal force, and may be provided by means acting not in a strictly centripetal direction.

Similarly, a centrifugal force or movement may be understood as referring to that vector or component of a complex force or movement acting or allowing action in a centrifugal direction.

In some embodiments of the present invention, the effective centripetal force is provided by a spring or elastic compressible member which urges or biases the dynamic means substantially along or parallel to the axis of rotation of the yo-yo.

By acting on at least one of the yo-yo string and at least one lateral face of the string bearing means, the seizing means of the present invention allows for a reduction in the surface area of the string bearing means in contact with the axial member and consequent reduction of friction resulting in potentially longer spinning times. It also allows for interchangeability of string bearing means of various compositions and properties to suit the operator.

Further, when acting along the axis of rotation of the yo-yo, symmetrically and opposedly about the mid-point between the medial faces of the two yo-yo halves, optionally at a radial distance out from the circumference of contact between string and string bearing means, the seizing means of the present invention provides a superior centering and lateral support/control means for the yo-yo string between the two yo-yo halves which has been found to provide improved resistance to precession. This in combination with the seizing of the string and/or string bearing means at the apogee of the loop-the-loop throw is thought also to contribute to the superior loop-the-loop capacity of the automatically returning yo-yo of the present invention. Thus the yo-yo of the present invention uniquely combines the positive characteristics of two different modes of yo-yo performance, usually requiring different yo-yo settings: loop-the loop and long spin capacity necessary for string tricks.

Those embodiments wherein the string rather than the string bearing means is seized allow a single-loop string attachment in an automatically returning yo-yo. This can also be achieved by incorporating a suitable flange on the annular seizing means of those embodiments in which the vertical faces of the string bearing means are seized such that there is interference with the string.

WO 99/03547 PCT/AU98/00545 -6- In those embodiments where the yo-yo is, in response to its speed of rotation, automatically prevented from spinning freely with respect to the string bearing member by the compressive seizing of at least one lateral face of the string bearing member only, a secure attachment of the string to the string bearing member is required so that the yo-yo is forced to climb the string to the operator's hand, and a double loop string attachment is recommended.

The seizing means of the present invention, when acting on the lateral face of the string bearing means, allows the effective operation of the present invention in an embodiment incorporating the invention in only one yo-yo half It should be understood that the automatically returning yo-yo of the present invention may also be returned to the operator's hand at any time prior to engagement of the automatically activated means by the operator flicking or jerking the string.

It is within the scope of the present invention to include the seizing/tripping/centering/lateral support means in one or both yo-yo halves. It is also within the scope of the present invention to use the axial member as the string bearing means.

Brief Description of the Drawings The invention is described in greater detail hereinafter, by way of example only, with reference to several embodiments thereof illustrated in the accompanying drawings, wherein: FIG. 1 is an enlarged sectional detail through the diameter of the yo-yo showing the axial member and the effectively reciprocatingly acting members; FIG. 2 is a sectional view taken through the diameter of the yo-yo, showing centrifugally (left) and centripetally (right) influenced states; FIG. 3 is an elevation of the lateral face of the yo-yo showing an embodiment of the dynamic centrifugally/centripetally activated means; FIG. 4 is an enlarged radial sectional detail through the region of the circumference of a yo-yo half showing the cam surface translation means of a preferred embodiment; FIG. 5 is a side elevation of a four-spoked embodiment of the present invention, shown in WO 99/03547 PCT/AU98/00545 -7perspective in FIG. 6; FIG. 7 is a side elevation of a two-spoked embodiment of the present invention; and FIG. 8 is an enlarged sectional detail through the diameter of the yo-yo showing the axial member and the effectively reciprocatingly acting members in an embodiment in which the string bearing means is seized.

Detailed Description of the Preferred Embodiments With reference to the drawings, an embodiment of the yo-yo of the present application is shown which includes two yo-yo halves. The outer body of each half is further composed of two casing parts. A first casing part I comprises the inner or medial face provided with a recess 15 to accommodatethe string bearing means 3 and optional adjacent seizing/freeing/lateral supporting and/or centering means 4; and bores 12 to accommodate the corresponding effectively centrifugally/centripetally activated push/pull rods 14; the outer rim, axial bore and boss. On the medial faces of component 1 surrounding the said recess may be provided a plurality of radially arranged ribs 13, optionally raised, to assist the winding and unwinding of the yo-yo string The second casing part 2 is a cap, which provides the outer or lateral face of the yo-yo half The cap 2 is optionally provided with means 17 (FIG. 4) to snap lock into position. The medial rim 16 of the cap flange is optionally provided with a suitable profile to assist in the secure location of decorative means.

The two yo-yo halves are joined by an axial connected or connecting member, such as, in the embodiment shown in detail in FIG. 1, a threaded axle 5. In this case, each said yo-yo half is provided with a threaded nut 6 inserted and suitably secured into the axial boss via the lateral face of the first casing part. The yo-yo halves are then joined by inserting the threaded axle through the axial bores via the yo-yo medial faces and screwing the axle into the said nuts.

Again with reference to FIG. 1 shown moveably located on this axial member are seizing/freeing/laterally supporting and/or centering means 4 (hereinafter referred to as seizing/centering means) in the form of optionally flanged annuli, located coaxially adjacent either or both side(s) of a string bearing means 3 and able to transmit any movement, vector, signal or WO 99/03547 PCT/AU98/00545 -8urge from the dynamic means to the string and/or the string bearing means. Said seizing/centering means are provided with means to accept the push/pull rods 14 of component 8 when in effective centripetal/centrifugal modes respectively. The said rods 14 are designed to operatively engage, lock and guide the seizing/centering means thereby increasing the grip on the string and/or the string bearing means when in effective centripetal mode and clearing the string and/or string bearing means when in centrifugal mode. A detail of a suitable locking means 18 is shown in FIG. 1. The seizing, centering and lateral support of the string by the seizing/centering means enables a superior balanced yo-yo that performs excellently as a loopthe-loop yo-yo while maintaining superior performance as a free-spinning yo-yo and also allows the preferred modality of single loop string attachment.

FIG. 8 shows a detail of an embodiment in which the seizing/centering means acts directly on the lateral face(s) of the string bearing means only. Flange arrangements from the zero flange of FIG. 8 to the string only snaring flange of FIG. 1 are all comprehended in the present invention, as are various dimensions of the annulus and flange.

In another embodiment (not shown), the rods 14 may act directly on the string or another seizing means.

Optionally, the locking and guiding means may also be achieved or augmented by projections from the seizing/centering means engaging corresponding recesses in the medial face of the recess 15 or by projections from the said medial face into recesses in the seizing/centering means.

A string bearing means 3 rotatably supported on the axial member is provided comprising optionally a ball or roller bearing, a molded, pressed or machined spool, a low friction plastic spool, a metal spool, a wooden spool, a dual or multi-layered spool, a grooved stringaccommodating spool, and/or a spool with anti-string-slip qualities. It is a preferred feature of the yo-yo of the present invention that the string bearing means be interchangeable according to the performance characteristics desired by the operator.

According to the present invention, inside one or both of the yo-yo halves is housed dynamic WO 99/03547 PCT/AU98/00545 -9centrifugally/effectively centripetally activated means acting upon the seizing/centering means or the string. One form of this is shown in FIG. 2 in the centrifugally influenced mode (left yo-yo half) and effective centripetally influenced mode (right yo-yo half). The dynamic activated means comprises four components or multiples of these components. In the embodiments shown the components are: a centrifugally activating mass 7, a centripetally/centrifugally engaged or allowed counter force means 9, a translation means 10 and a centrifugally and effectively centripetally activated displaceable means 8 acted upon by said mass and said counter force and acting upon the seizing/centering means 4 in an effectively reciprocating motion parallel to the axis of rotation of the yo-yo. Access to influence the seizing/centering means is provided for said displaceable means by one or more bores 12 through the outer face of casing part 1.

Components 7 and/or 8 and/or 9 utilize components 1 and/or 2 as support structure, by way of position and/or shape and/or coefficient of friction and/or substantiality and/or kinetic potential, to facilitate the transfer to dominance of effective centripetal or centrifugal mode at a predetermined speed of rotation of the yo-yo.

The embodiment depicted in elevation in FIG. 3 utilizes three steel balls arranged in a threespoked array in each yo-yo half for the said mass. Fig. 5 shows a side elevation of a four-spoked array utilizing four steel balls, shown in perspective in Fig. 6. This arrangement also possesses extremely good balance. Fig. 7 is a side elevation of a two spoked array. When this said mass is centrifugally influenced it travels along a cam surface 10, shown in detail in FIG. 4, said cam surface being the translation means of the embodiment shown, thereby laterally displacing the displaceable means 8 and pulling back the seizing/centering means 4 by means of push/pull rods 14 from contact with the yo-yo string and/or the lateral face(s) of the string bearing means. In an alternative embodiment, the push/pull rods may release the seizing/centering means upon contact with the adjacent inner face of the recess 15 or the medial face of the yo-yo half The seizing/centering means, should it contact the string, is thus free to spin, thereby providing reduced interference to the free spinning yo-yo. The cam surface 10 maintains the centrifugally activated mass in an unstable position until the decaying centrifugal force can no longer resist the effective centripetal counter force provided by counter force means 9, in this embodiment a spring or elastic compressible means. The displaceable means is activated and the push/pull rods WO 99/03547 PCT/AU98/00545 carry the seizing/centering means towards the yo-yo string and/or the lateral face(s) of the string bearing means until seizure is achieved and the yo-yo automatically returns at a predetermined speed. This embodiment is understood as but one engineering method to utilize the said centrifugavcentripetal forces or counter-centrifugal acting means either directly or indirectly. The invention could utilize lever, pivot, elbow, spring, push or pull means, elastic, electric or electronic, pneumatic, magnetic and/or hydraulically activated means or any combination thereof with one or multiple components effecting the same function of seizing/freeing/lateral supporting/centering and/or tripping of the yo-yo string and/or string bearing means. By way of example, an alternative embodiment could include a centrifugally activated switch completing a circuit and activating a solenoid.

Optionally component 4 can be bypassed or not included when direct tripping of the yo-yo string is a preferred embodiment. This is achieved by extending part 14 through the medial face of one or both yo-yo halves to intercept the path of the yo-yo string directly and when centrifugally activated clear the path of the yo-yo string, in which case bores 12 would traverse casing part

I.

Optionally said effective centripetal counter force 9 could be incorporated within the design of component 8 by utilizing a material and/or shape that develops rebound effective centripetal capacity when compressed by the centrifugal force generated by the spinning yo-yo. Said displaceable means 8, shown in the drawings as a three-spoked embodiment, is provided with means to afford said mass 7 an operatively secure location, allow movement from a static/stable position to a dynamic/unstable position, and promote ease of assembly by an optional clip-intoposition design. The design can allow the inclusion of decorative means securely held between the displaceable means 8, the lateral face of component 1 and the medial rim of the cap 16.

The present invention, by acting on the yo-yo string and/or the lateral face(s) of the string bearing means, allows a range of superior spinning bearings to be modularly used while still achieving the function of an automatically returning yo-yo. By centering and laterally supporting the yo-yo string a superior balanced yo-yo is provided which exhibits excellent loop-the-loop characteristics and ease of operation especially for beginners.

WO 99/03547 PCT/AU98/00545 -11- In a further embodiment of the present invention (not shown), the seizing/centering means are associated with only one yo-yo half and compressively force the string bearing means laterally against the medial face of the other yo-yo half so as to prevent the yo-yo from spinning relative to the string bearing means.

Yet another embodiment of the present invention, again not shown, provides the annular seizing/centering means with a flange able to project a suitable distance over the circumferential face of the string bearing means so as to center the yo-yo string.

Yet another embodiment of the present modifications, again not shown, allows the displaceable member 8, suitably adapted, to act directly on the lateral face(s) of the string bearing means.

Suitable materials for the manufacture of the seizing/centering means of the present modifications include polyacetyl, nylon and other materials and alloys with a high resistance to wear and to friction-generated heat, and which are able to be molded and/or machined.

A wide range of materials are suitable for the manufacture of the yo-yo body of the present invention, however the preferred embodiment utilizes injection molded plastic for the substantial parts.

It is understood that the above description is intended to be illustrative and that other embodiments may be apparent to those skilled in the art without departing from the spirit of the claimed invention.

Q:\OPER\GCP\82012c.doc-18/08/00 -12- The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (28)

1. An automatically returning yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and defining an axis of rotation about which said yo-yo halves can rotate; a string having one end connected to said axle-assembly between said yo-yo halves; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: movement in a direction which is at least substantially parallel to said rotation axis, the linear position of said engagement-member being dependent on the rotational :i i 5 velocity of said clutch; and at least one biasing member for resiliently urging said engagement-member into engagement with a portion of at least one of said string and said axle-assembly when the rotational velocity of said clutch is below a predetermined value. *o o.

2. The yo-yo of claim 1 wherein: said axle-assembly includes at least one braking surface, and said engagement member is linearly urged into engagement with said braking to" surface of said axle-assembly when the rotational velocity of said clutch is below said predetermined value.

3. The yo-yo of claim 1 wherein: said yo-yo halves have medial faces with respective mid-points, said mid-points lying on said rotation axis; and said engagement member is disposed for substantially linear movement along, and 0 acts symmetrically about, said rotation axis. Q\OPER\GCPMS2012cdmoc-18/080 -14-

4. The yo-yo of claim 1 wherein said clutch further comprises at least one of a cam, a cam surface, a lever, an elbow and a pivot means. The yo-yo of claim 1 wherein said engagement member includes at least one centrifugally influenced mass and translation means for converting centrifugally directed forces into axially directed forces, said translation means being operatively associated with said mass.

6. The yo-yo of claim 5 wherein said engagement member includes a plurality of centrifugally influenced masses and said translation means are operatively associated with said masses. oo o 7. The yo-yo of claim 1 wherein: 000said axle-assembly comprises a string bearing member and an axle which is 000 15 stationary relative to at least one of said yo-yo halves, said string bearing member having o o at least one braking surface, being mounted on said axle and being freely rotatable relative thereto; said one string end is connected to said string bearing member; and 0000 .said engagement member is urged into engagement with at least one of said string o~ooo and said braking surface when the rotational velocity of said clutch is below said ~o o S predetermined value. 0 0 oooo oooooo o o oo o 00 8. The yo-yo of claim 7 wherein said engagement member includes at least one o 0 flanged annulus such that said engagement member is urged into engagement with said string when the rotational velocity of said clutch is below said predetermined value.

9. The yo-yo of claim 7 wherein: said yo-yo halves have medial faces, and said string bearing member is rotatably mounted on said axle at or near a midpoint between said medial faces of said yo-yo halves. Q:\OPER\GCP2012c.do-1810800 -16- disposed for substantially linear movement within said second plane.

17. The yo-yo of claim 16 wherein: said means for coupling includes means for bearing said string, said means for bearing having at least one lateral face; said string is connected to said means for bearing; and said clutch means includes at least one engagement member disposed for substantially linear movement in a direction which is at least substantially parallel to said rotation axis, the linear position of said engagement member being dependent on the rotational velocity of said clutch means, said clutch means also including at least one biasing member for resiliently urging said engagement member into engagement with at S. least one of said string ends and said means for bearing when the rotational velocity of said clutch means is below a predetermined value.

18. The yo-yo of claim i 7 wherein said engagement member is urged into engagement ".1with both of said string ends and said means for bearing when the rotational velocity of said clutch means is below said predetermined value. ,o S. oe* 19. The yo-yo of claim 16 wherein: said clutch means includes at least one means for engaging disposed for o_ substantially linear movement in a direction which is at least substantially parallel to said rotation axis; the position of said engagement member is dependent on the rotational velocity of said clutch means; and said clutch means also includes means for urging said means for engaging into engagement with at least one of said string and said means for coupling when the rotational velocity of said clutch is below a predetermined value. An automatically returning yo-yo comprising: 0 a first rotatable yo-yo half; A a second rotatable yo-yo half; QAOPER\GCP\92012c.doc.I8IOS/O -17- an axle-assembly mechanically coupling said first and second yo-yo halves and defining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly comprising a string bearing member and an axle which is stationary relative to at least one of said yo-yo halves, said string bearing member having at least one braking surface, being mounted on said axle and being freely rotatable thereto; a string having one end connected to said string bearing member between said yo-yo halves; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one engagement member disposed for substantially linear movement in a direction which is at least substantially parallel to said rotation axis, the linear said clutch; and at least one biasing member for resiliently urging said engagement member into i 15 engagement with at least one of said string and said braking surface when the rotational velocity of said clutch is below a predetermined value.

21. The yo-yo of claim 20 wherein said engagement member includes at least one flanged annulus mounted on said axle-assembly.

22. The yo-yo of claim 21 wherein said engagement member is urged into engagement with both of said string and said braking surface.

23. The yo-yo of claim 21 wherein said engagement member is capable of engaging said string bearing member without interfering with the string.

24. The yo-yo of claim 21 wherein said engagement member is capable of engaging said string without interfering with said string bearing member. 0 25. The yo-yo of claim 20 wherein said engagement member is substantially coaxially z adjacent said string bearing member. Q:\PER\GCP821012.dc.d-18/08/00 -18-

26. The yo-yo of claim 20 wherein: said yo-yo halves have medial faces with respective mid-points, said mid-points lying on said rotation axis; and said engagement member is disposed for substantially linear movement along, and acts symmetrically about, said rotation axis.

27. The yo-yo of claim 20 wherein said engagement member includes at least one centrifugally influenced mass and translation means for converting centrifugally directed forces into axially directed forces, said translation means being operatively associated with said mass.

28. The yo-yo of claim 27 wherein said clutch further comprises at least one of a cam, a cam surface, a lever, an elbow and a pivot means. o: 29. The yo-yo of claim 27 wherein said engagement member includes a plurality of centrifugally influenced masses and said translation means are operatively associated with said masses. 20 30. The yo-yo of claim 29 wherein said clutch is arranged in a three-spoke array.

31. The yo-yo of claim 20 wherein said string bearing member is interchangeable. o

32. The yo-yo of claim 20 wherein at least a portion of said clutch can be removed to thereby convert said automatically returning yo-yo into a non-automatically returning yo- yo.

33. An automatically returning yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and Q:\OPER\GCI2012c.doc-18/08A00 -19- defining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly having an axle and a string bearing member mounted on and freely rotatable relative to said axle; a string having one end connected to said string bearing member; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one engagement-member disposed for substantially linear movement in a direction which is at least substantially parallel to said rotation axis, the linear position of said engagement member being dependent on the rotational velocity of said clutch; and at least one biasing member for resiliently urging said engagement member into engagement with said string when the rotational velocity of said clutch is below a predetermined value. .i 15 34. The yo-yo of claim 33 wherein said string bearing member has a braking surface and said engagement member includes at least one flanged annulus mounted on said axle- assembly. The yo-yo of claim 34 wherein said engagement member is urged into engagement 20 with both of said string and said braking surface.

36. The yo-yo of claim 34 wherein said engagement member is capable of engaging *said string bearing member without interfering with the string.

37. The yo-yo of claim 34 wherein said engagement member is capable of engaging said string without interfering with said string bearing member.

38. The yo-yo of claim 33 wherein said engagement member is substantially coaxially Sadjacent said string bearing member.

39. The yo-yo of claim 33 wherein: QAOPERkGCP\82012c.dom-1/08/ said yo-yo halves have medial faces with respective mid-points, said mid-points lying on said rotation axis; and said engagement member is disposed for substantially linear movement along, and acts symmetrically about, said rotation axis. The yo-yo of claim 33 wherein said engagement member includes at least one centrifugally influenced mass and translation means for converting centrifugally directed forces into axially directed forces, said translation means being operatively associated with said mass.

41. The yo-yo of claim 40 wherein said clutch further comprises at least one of a cam, S•a cam surface, a lever, an elbow and a pivot means.

42. The yo-yo of claim 40 wherein said engagement member includes a plurality of o1..i 5 centrifugally influenced masses and said translation means are operatively associated with said masses. .000

43. The yo-yo of claim 42 wherein said clutch is arranged in a three-spoke array. oooo ooeo 0 20 44. The yo-yo of claim 33 wherein said string bearing member is interchangeable. •o

45. The yo-yo of claim 33 wherein the string bearing member can be removed to thereby convert said automatically returning yo-yo into a non-automatically returning yo-yo.

46. An automatically returning yo-yo comprising: a first rotatable yo-yo half; a second rotatable yo-yo half; an axle-assembly mechanically coupling said first and second yo-yo halves and Sdefining an axis of rotation about which said yo-yo halves can rotate, said axle-assembly 1 having an axle; Q:\OPER\GCPM82012c.doc-18/00 -21- a string having one end connected to said axle-assembly with a single-loop string attachment; and at least one centrifugally-activated clutch which rotates with at least one of said yo-yo halves, said clutch including: at least one movable engagement member wherein the position of said engagement member is dependent on the rotational velocity of said clutch; and at least one biasing member for resiliently urging said engagement member into engagement with said string when the rotational velocity of said clutch is below a predetermined value; said engagement member is disposed for substantially linear movement along, and acts symmetrically about, said rotation axis. S: 47. The yo-yo of claim 46 wherein said axle-assembly further comprises a string bearing member which has a braking surface and wherein said engagement member includes at least one flanged annulus mounted on said axle-assembly.

48. The yo-yo of claim 46 wherein said yo-yo halves have medial faces with respective mid-points, said mid-points lying on said rotation axis. :49. The yo-yo of claim 46 wherein said engagement member includes at least one 20 centrifugally influenced mass and translation means for converting centrifugally directed ••go forces into axially directed forces, said translation means being operatively associated with said mass. A yo-yo substantially as hereinbefore described with reference to the accompanying drawings. DATED this 18th day of August, 2000 BRENDON MICHAEL O'SULLIVAN By his Patent Attorneys DAVIES COLLISON CAVE