Spin device for racket

Description

BACKGROUND OF THE INVENTION

This application claims priority to U.S. Application 63/725,843, filed Nov. 27, 2024, the content of which is incorporated by reference.

Racket performance in racquet sports has been incrementally improved through string innovations, frame shaping, and peripheral attachments intended to increase ball spin and shot control. Yet many existing approaches introduce trade-offs in weight distribution, durability, or maintenance. Frame-mounted fixtures and external add-ons can interfere with balance and aerodynamics, while conventional damping and grommet systems offer limited capacity for controlled rotational movement of the racket and often suffer from increased friction and wear. There remains a need in the field for compact, low-profile solutions that can accommodate localized relative motion near the throat region without compromising structural integrity, playability, or service life.

SUMMARY OF THE INVENTION

In one aspect, a method of enabling spinning of a racket using a spin device comprises providing a spin device that includes a first surface and a second surface, each having an inner edge and an outer edge, the outer edges being convex. The outer edges of the first and second surfaces are connected by a third surface that is concave and configured to contact a throat portion of the racket. The inner edges of the first and second surfaces are connected by a fourth surface that defines a recess. A bearing having an outer surface is inserted into the recess so that the bearing outer surface is received by the recess of the fourth surface. The spin device is affixed to the throat portion of the racket such that the racket rotates with the spin device.

Advantages of one implementation may include one or more of the following:

• • A compact, low-profile form factor that conforms to the racket throat and minimizes interference with aerodynamics and swing balance.
  • Localized allowance for controlled relative rotational movement at the throat region without degrading overall frame structural integrity.
  • A bearing received in the recess that provides smooth, low-friction rotation and reduces wear compared to sliding interfaces.
  • Reduced frictional heat and abrasion at the contact interface, increasing component service life.
  • Minimal impact on weight distribution and balance due to the small footprint and integration close to the frame centerline.
  • Preservation of playability and string bed behavior by avoiding direct modification to the stringing area and grommet system.
  • Predictable and tunable rotational resistance (via bearing selection, lubrication, or geometry) to suit different player preferences and play conditions.
  • Ease of installation as an integrated or retrofit element—suitable for factory assembly or field replacement—reducing maintenance complexity.
  • Replaceable bearing and modular construction that permit straightforward servicing and parts replacement without permanent modification to the racket frame.
  • Compatibility with a range of throat geometries and racket designs through scalable dimensions and simple mating surfaces.
  • Reduced noise and vibration transmission relative to many external fixtures, improving player feel and feedback.
  • Improved durability versus many peripheral add-ons because the design distributes loads into the throat and uses rolling elements instead of high-friction sliding joints.
  • Cost-effective manufacture and assembly using standard materials and processes (e.g., molded polymers, machined metals, standard bearings).
  • Ability to combine with other throat-region features (dampers, braces, cosmetic covers) without significant packaging conflicts.
  • Aesthetically low-impact integration that preserves racket appearance while providing functional benefits.

These advantages are exemplary and not limiting; additional benefits and variations will be apparent to those skilled in the art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example of an isometric view of a spin device;

FIG. 2 shows an example of a side view of the spin device;

FIG. 3 shows an example of a top view of the spin device;

FIG. 4 shows an example of a bottom view of the spin device;

FIG. 5 shows an example of straps passing through slots of the spin device;

FIG. 6 shows an example of a spin device system;

FIG. 7 shows an example of a racket spinner system;

FIG. 8 shows an example of the racket spinner system;

FIG. 9 shows an example of a strap;

FIG. 10 shows an example of a bearing;

FIG. 11 shows an example of an isometric view of a spin device;

FIG. 12 shows an example of a front view of the spin device;

FIG. 13 shows an example of a rear view of the spin device;

FIG. 14 shows an example of a right-side elevation view of the spin device;

FIG. 15 shows an example of a left-side elevation view of the spin device;

FIG. 16 shows an example of a top view of the spin device;

FIG. 17 shows an example of a bottom view of the spin device;

FIG. 18 shows an example of a spin device system;

FIG. 19 shows an example of a racket spinner system;

FIG. 20 shows an example of a spin device system; and

FIG. 21 shows a spinner with a pickleball paddle.

DETAILED DESCRIPTION OF THE INVENTION

In one example, a spin device includes a first surface with an inner edge and an outer edge, wherein the outer edge of the first surface is convex; a second surface with an inner edge and an outer edge, wherein the outer edge of the second surface is convex; a third surface connecting the outer edge of the first surface to the outer edge of the second surface, wherein the third surface is concave and configured to contact a throat of a racket; and a fourth surface connecting the inner edge of the first surface to the inner edge of the second surface, wherein the fourth surface defines a recess configured to receive an outer surface of a bearing. The device makes it easier to spin a racket at the throat using a finger, which enables a player to quickly rotate the frame.

In a second example, the techniques described herein relate to a spin device including: a top surface having an inner edge and an outer edge, wherein the outer edge of the top surface is convex; a bottom surface having an inner edge and an outer edge, wherein the outer edge of the bottom surface is convex; an outer surface connecting the outer edge of the top surface and the outer edge of the bottom surface, wherein the outer surface is concave; and an inner surface connecting the inner edge of the top surface and the inner edge of the bottom surface, wherein the inner surface defines a recess; wherein the spin device defines a slot extending between the top surface and the bottom surface; a bearing at least partially seated within the recess of the fourth surface; and a strap passing through the slot, wherein the strap is configured to affix the spin device to a throat portion of a racket.

In a third example, the techniques described herein relate to a racket spinner system including: a spin device system including: a spin device having a top surface, a bottom surface, and an outer surface, wherein the outer surface is concave; a bearing positioned between the top surface and the bottom surface of the spin device, the bearing is configured to permit rotation of the spin device; and a strap passing through a slot defined between the top surface and the bottom surface of the spin device; and a racket having a throat between a handle portion and a head portion; wherein: the strap of the spin device system is secured around a portion of the throat of the racket; the outer surface of the spin device is in contact with an inner surface of the throat; the racket is configured to rotate with the spin device.

Another example relates to a device with a body with top and bottom surfaces having convex outer edges, a concave outer surface shaped to nest against inner throat surfaces of a racket, and an inner surface with a recess that receives the outer ring of a bearing. One or more slots through the body accept a strap or other fastener to affix the device across the racket throat. A bearing positioned between the top and bottom surfaces allows the device and the coupled racket to rotate together while a user's finger engages the bearing's inner ring. Systems include the device, bearing, and fastener secured to a racket; methods include mounting the device at the throat and spinning the racket around an axis that passes through the device opening. Variations include different body shapes such as circular, triangular, or truncated forms, different materials ranging from rigid plastics to elastomers, and different slot and fastener arrangements.

Yet another example relates to a device with a body with top and bottom surfaces having convex outer edges, a concave outer surface shaped to nest against inner throat surfaces of a racket, and an inner surface with a recess that receives the outer ring of a bearing. One or more slots through the body accept a strap or other fastener to affix the device across the racket throat. A bearing positioned between the top and bottom surfaces allows the device and the coupled racket to rotate together while a user's finger engages the bearing's inner ring. Systems include the device, bearing, and fastener secured to a racket; methods include mounting the device at the throat and spinning the racket around an axis that passes through the device opening. Variations include different body shapes such as circular, triangular, or truncated forms, different materials ranging from rigid plastics to elastomers, and different slot and fastener arrangements.

Yet a further example relates to spin devices for rackets and racket-spinner systems. The device comprises a body with a bearing-supported rotating interface that enables controlled spinning of tennis, pickleball, squash, badminton, or similar rackets at the throat region. The technology facilitates quick grip transitions, pre-serve rituals, equipment checks, and provides entertainment value while maintaining smooth rotation around an axis perpendicular to the racket's longitudinal axis.

The spin device includes a body with top and bottom surfaces having convex outer edges, a concave outer surface shaped to nest against inner throat surfaces of a racket, and an inner surface with a recess that receives the outer ring of a bearing. One or more slots through the body accept a strap or other fastener to affix the device across the racket throat. A bearing positioned between the surfaces allows controlled rotation while a user's finger engages the bearing's inner ring.

Device Body Configuration

The core body comprises a generally annular component having a first surface, a second surface, a third surface, and a fourth surface. The first surface and second surface may also be referred to as a top surface and bottom surface respectively, and face one another with each including an inner edge and an outer edge. The outer edges of both surfaces are convex, extending radially outward beyond the corresponding inner edges to create a rounded peripheral profile that facilitates smooth contact and load distribution.

The outer edges may be substantially circular in shape, with the inner edges having a diameter less than a diameter of the outer edges. The diameter of the inner edges may be substantially equal to each other, and the diameter of the outer edges may be substantially equal to each other. The convexity of the outer edges allows the spin device to contact an object and provides multiple points of contact for stable coupling.

The third surface extends between the outer edges of the first and second surfaces and is concave or beveled to nest against the inner surface of a racket throat for a tennis racket (and if alternatively coupled to a pickleball paddle, this would occur on the side of the paddle as most paddles do not have throat openings). This concave geometry creates complementary curvatures that self-center the device and resist lateral movement when seated. The concavity may be structured to align with the convexity of inner throat surfaces, allowing the throat to be at least partially seated in the spin device.

The fourth surface extends between the inner edges of the first and second surfaces and defines an annular recess sized to receive the outer ring of a bearing. The recess may be an indentation or series of indentations configured to align with the bearing or portions of the bearing surface. The fourth surface also defines an interior passage that permits objects to pass through the spin device.

The device defines a central passage bounded by the bearing's inner ring, dimensioned to receive a user object such as a finger, stylus, or tool. The passage diameter is selected to provide comfortable insertion while maintaining control during rotation. The interior passage permits objects to extend through the spin device, with typical inner diameters ranging from 15 mm to 20 mm in one case and 10 mm to 30 mm in another case, accommodating different user object sizes including Small, Medium, and Large size categories. The passage is large enough for a finger to pass through comfortably, yet close enough in size to give the user good control of the device. Its edges are rounded or chamfered to avoid discomfort during use.

FIG. 1 illustrates an exemplary view of a spin device 100. The spin device includes a top surface 105 with an inner edge 110 and an outer edge 115, and a bottom surface 120 with an inner edge 125 and an outer edge 130. The outer surface 135 connects the outer edges of the top and bottom surfaces and is concave/beveled to contact a racket throat. The inner surface 140 connects the inner edges and defines a recess 145 and an interior passage 160. The device also defines slots 150 and 155 that extend between the top and bottom surfaces for threading straps.

The inner edge 110 and the outer edge 115 of the top surface 105 and the inner edge 125 and the outer edge 130 of the bottom surface 120 may each be convex. For example, the edges 110, 115, 125, 130 may be substantially circular in shape, with the inner edges 110, 125 having a diameter less than a diameter of the outer edges 115, 130. The diameter of the inner edges 110, 125 may be substantially equal. The diameter of the outer edges 115, 130 may be substantially equal. The convexity of the outer edges 115, 130 allows the spin device 100 to contact an object. Additionally, the diameters of any of the edges 110, 115, 125, 130 of the spin device 100 may correspond to the size of an object. The outer surface 135 of the spin device 100 may be concave or beveled. A portion of an object may substantially align with the concavity of the outer surface 135.

The spin device 100 may be or may include a variety of materials. For example, the spin device 100 may be or may include a stiff or hard material, such as metal, PVC, or the like. In these examples, the spin device 100 may include a retention ring and clips, which may inhibit the spin device 100 from decoupling from an object. In other examples, the spin device 100 may be or may include a soft or flexible material, such as rubber, soft plastic (e.g., TPU), or the like. In these examples, the spin device 100 may include a plurality of retention rings, which may inhibit the spin device 100 from decoupling from an object.

The spin device 100 may define at least one slot, such as a first slot 150 and a second slot 155. The slots 150, 155 may be defined between the top surface 105 and the bottom surface 120 of the spin device 100. The slots 150, 155 may extend through the top surface 105 and the bottom surface 120, such that an object such as a strap can be threaded or passed through the slots 150, 155. For example, the slots 150, 155 may be hollow interior cavities extending through a thickness of the spin device 100. The slots 150, 155 may be curved. The curvature of the slots 150, 155 may substantially align with or correspond to at least one of the diameters of the edges 110, 115, 125, 130.

FIG. 2 shows a side elevation view, or a two-dimensional profile, of the spin device (100). This view shows the top surface (105) as the uppermost line or curve and the bottom surface (120) as the parallel, lowermost line, establishing the device's fundamental thickness. Most notably, this side angle reveals the concave or beveled geometry of the outer surface (135), showcasing its inwardly curved profile designed to nest securely against the convex inner surface of a racket's throat.

FIG. 3 presents a top plan view of the spin device (100), looking directly down onto its first or top surface (105). It shows the top surface (105) in its entirety, bounded by its inner edge (110) and outer edge (115). The convex, circular nature of the outer edge (115) is shown as a smooth, continuous ring that extends radially outward. The central feature of this view is the interior passage, which is revealed as a circular opening defined by the inner edge and providing access to the bearing assembly. The positioning and layout of the fastening slots are also clearly detailed in this top-down view; the first slot (150) and second slot (155) are visible as elongated apertures extending through the body. They are depicted on substantially opposite sides of the central axis of the device, an arrangement that ensures balanced loading and secure attachment when straps are tensioned around the throat of a racket or paddle.

FIG. 4 shows a bottom plan view of the spin device (100), offering a view of its second or bottom surface (120). The entire bottom surface (120) is, bounded by its inner edge (125) and its convex outer edge (130), mirroring the circular symmetry of the top surface. The central interior passage (160) is again prominently featured, appearing as a circular opening defined by the inner edge (125) and providing a view through to the opposite side. This view also confirms the placement and path of the fastening slots from the bottom perspective; the first slot (150) and second slot (155) are clearly visible as apertures that perforate the device's body. Their positioning on substantially opposite sides of the central axis is consistent with the top view, highlighting the design intent for balanced force distribution.

FIG. 5 illustrates straps passing through the slots of the spin device 100. It shows a first strap 505 passing through the first slot 150 and a second strap 510 passing through the second slot 155, demonstrating how the straps can be threaded through to couple the device to an object. Each of the slots 150, 155 may receive at least one strap. For example, a strap may extend through or pass through at least one of the slots 150, 155. With the straps 505, 510 passing through the slots 150, 155, the straps 505, 510 may couple the spin device 100 to an object. With the spin device 100 coupled with an object, the spin device 100 may permit or enable rotation of the object.

FIG. 6 shows an example of a spin device system 600. The device has a distinctive central opening labeled as 160, which serves as an interior passage through which a user can insert their finger to interact with the bearing mechanism housed within (labeled as 1000). Two straps 505 and 510 extend from opposite sides of the spin device. These straps pass through slots in the device body and are configured to wrap around the throat portions of a racket or paddle to secure the entire system in place.

FIGS. 7 and 8 show examples of a racket spinner system 700. The racket spinner system 700 may include a racket 705 and at least one of the spin device systems 600. The racket 705 may include a handle portion 710, a head portion 730, and a throat 715. The throat 715 may be positioned between the handle portion 710 and the head portion 730. The throat 715 may include at least one portion 725. For example, the portion 725 may be referred to as a leg 725 of the throat 715. The throat portion 725 may include at least one surface, such as an inner surface 720. For example, each of the legs 725 includes an inner surface 720.

The spin device system 600 or the spin device 100 may be coupled, e.g., directly or indirectly, with the racket 705. The spin device system 600 or the spin device 100 may be permanently or temporarily coupled with the racket 705. For example, the spin device system 600 or the spin device 100 may be an integral feature of the racket 705.

With the spin device system 600 or the spin device 100 coupled with the racket 705, the outer surface 135 of the spin device 100 may be in contact with the inner surface 720 of the throat 715. The convexity of the outer edges 115, 130 of the spin device 100 may allow the spin device 100 to contact or align or abut convex surfaces of the throat 715. For example, the inner surfaces 720 of the throat 715 may be convex. In this example, the opposing convexities of the inner surfaces 720 and the outer edges 115, 130 may allow the spin device 100 to easily sit within the throat 715 of the racket 705. With the opposing convexities of the inner surfaces 720 and the outer edges 115, 130, the spin device 100 has multiple points of contact with the throat 715 of the racket 705, which may provide a more stable or secure coupling of the spin device 100 and the racket 705. Since many rackets include convex inner surfaces, the convexity of the outer edges 115, 130 of the spin device 100 allow the spin device 100 to be seated in a variety of different brands and variations of rackets.

The inner surface 720 of the throat 715 may substantially align with the outer surface 135 of the spin device 100. The inner surface 720 of the throat 715 may be convex and the outer surface 135 of the spin device 100 may be concave. In this example, the concavity of the outer surface 135 of the spin device 100 may be structured to align with the convexity of the inner surface 720 of the throat 715, e.g., the throat 715 may be at least partially seated in the spin device 100. In some examples the outer surface 135 may be temporarily coupled with the inner surface 720, e.g., via a hook and loop system, magnetic coupling system, or the like. In some examples the outer surface 135 may be permanently coupled with the inner surface 720, e.g., the outer surface may be molded with the inner surface 720.

The straps 505, 510 may couple the spin device 100 to the racket 705. For example, the straps 505, 510 of the spin device system 600 may each be secured around each of the legs 725 of the throat 715 of the racket 705, respectively. Since the slots 150, 155 may be defined on substantially opposite portions of the spin device 100, the straps 505, 510 may extend through the slots 150, 155 and loop around each of the legs 725 of the throat 715, respectively, thereby tensioning the spin device 100 across the throat 715. This tension may inhibit or prevent the spin device 100 from moving, e.g., with the racket 705 in use.

The racket 705 may rotate with the spin device 100, e.g., with the bearing 605 rotating within the spin device 100 and interfacing with another object such as a human finger. For example, rotation of the racket 705 or of the spin device 100 may cause the other to rotate. A user object, such as a finger, may extend through the interior passage 160 of the spin device 100 and interface with the inner ring of the bearing 605. The diameters of any of the edges 110, 115, 125, 130 of the spin device 100 may correspond to the size of the user object. For example, spin devices 100 may be different sizes and structured to correspond to different ranges of sizes of user objects, such as Small, Medium, and Large.

The user object may be in contact with the inner surface of the bearing 605. The contact between the user object and the inner surface of the bearing 605 may inhibit or prevent rotation of the inner ring of the bearing 605. The balls within the center portion 1010 of the bearing 605 and the outer ring of the bearing 605 may permit rotation of the spinner device 100 and the racket 705. With the spinner device 100 and the racket 705 coupled together and the inner surface 140 of the spinner device 100 coupled with the outer surface of the outer ring of the bearing 605, both the spinner device 100 and the racket 705 will rotate together in response to a rotational force applied to the racket 705, e.g., a force applied at an angle to the handle portion 710 or the head portion 730, since the balls within the bearing 605 permit the inner and outer rings to rotate with respect to each other. The spin device 100 may enhance rotation of the racket 705 relative to a user object since the spin device 100 indirectly couples the racket 705 with the bearing 605. The racket 705 may spin about an axis extending through the interior passage 160, e.g., the axis may extend between the top surface 105 and the bottom surface 120 of the spin device 100. This axis of rotation may be substantially perpendicular to or at an abrupt angle to the axis of rotation extending through the length of the handle portion 710 e.g., extending between a distal end and a proximal end of the handle portion 710. With the axis of rotation through the interior passage 160 of the spin device 100, a user may spin the racket 705 in more than one way, e.g., about more than one axis of rotation. Additionally, with the axis of rotation through the interior passage 160 of the spin device 100, a larger moment of inertia, with respect to the moment of inertia enabled by the axis of rotation extending through the handle portion 710, may be enabled.

FIG. 9 shows an example of a strap 900. The strap 900 may be similar to or the same as the straps 505, 510. The strap 900 may include a body 920. The strap 900 may include at least one end, such as a first end 905 and a second end 915. The first end 905 and the second end 915 may be opposite each other, e.g., across the body 920. The strap 900 may define at least one opening 910. For example, the second end 915 may define the opening 910. The first end 905 of the strap 900 may pass through the opening 910 of the strap 900. The strap 900 may include a coupling system, such as a hook and loop system, a button system, a snap system, a magnetic system, or the like. The coupling system may couple one portion of the strap 900 to another portion of the strap 900. For example, the first end 905 may couple with the body 920. The coupling system may allow the strap 900 to couple with an object. For example, the first end 905 of the strap 900 may wrap around an object and pass through the opening 910 of the strap 900, such that the strap 900 is wrapped around the object. In this example, the first end 905 of the strap 900 may couple with the body 920 of the strap 900, which may secure the strap 900 to the object. The strap 900 may be permanently or temporarily secured to an object.

FIG. 10 depicts an example of a bearing 1000. The bearing 1000 may be similar to or the same as the bearing 605. The bearing 1000 may include at least one ring, such as a first or outer ring 1020 and a second or inner ring 1025. The bearing 1000 may include at least one surface, such as a first or outer surface 1005 and a second or inner surface 1015. For example, the outer ring 1020 may include or define the outer surface 1005 and the inner ring 1025 may include or define the inner surface 1015. The bearing 1000 may include a center portion 1010. The center portion 1010 may be disposed or extending between the outer surface 1005 and the inner surface 1015. The center portion 1010 may include at least one ball (not shown) and at least one cage (not shown) configured to secure the balls in a certain plane, while permitting rotation of the balls. In this example, the bearing 1000 may be referred to as a roller element bearing. The bearing 1000 may be any type of bearing, such as for example a plain bearing. The center portion 1010 may include at least one cover or sealing disc 1030. For example, a top surface and a bottom surface of the center portion 1010 may each include a cover 1030. The cover 1030 may secure the ball and the cage in the center portion 1010, e.g., between the outer and inner rings 1020, 1025. The balls within the center portion 1010 may contact inside surfaces of each of the outer and inner rings 1020, 1025, thereby permitting the outer and inner rings 1020, 1025 to rotate with respect to each other. For example, with an object contacting the inner surface 1015 of the inner ring 1025, the outer ring 1020 may rotate in response to a force applied, e.g., directly or indirectly, to the outer surface 1005. In this example, the object may inhibit rotation of the inner ring 1025.

In a second embodiment, an isometric view (FIG. 11), a front view (FIG. 12), a rear view (FIG. 13), a right-side elevation view (FIG. 14), a left-side elevation view (FIG. 15), a top view (FIG. 16), and a bottom view (FIG. 17) show a spin device or a body 1100. The spin device 1100 is similar to the spin device 100 and includes features similar to or the same as the spin device 100. For example, the spin device 1100 may include an outer surface that is concave or beveled that may substantially align with a surface of an object, the spin device 1100 may include an inner surface that may receive a bearing, and the spin device 1100 may define slots that may receive straps.

A spin device system 1800 that is substantially similar to the spin device system 600 is depicted in FIG. 18. A racket spinner system 1900 that is substantially similar to the racket spinner system 700 is depicted in FIG. 19. In this embodiment, the spin device 1100 may include or be a triangular or badge shape. The triangular form of the spin device 1100 may permit the spin device 1100 to sit in the bottom groove of the triangular opening defined by the throat of a variety of rackets, as depicted in FIG. 19.

In a third embodiment, a spin device system 2100 is shown (FIG. 20). The spin device 2100 is similar to the spin device 1100 and includes features similar to or the same as the spin device 1100. For example, the spin device 2100 may include an outer surface that is concave or beveled that may substantially align with a surface of an object, the spin device 2100 may include an inner surface that may receive a bearing, and the spin device 2100 may define slots that may receive straps. In this embodiment, the spin device 2100 may include or define a truncated shape, which may permit the spin device 2100 to couple with or be seated in a racket at a variety of locations within the triangular opening defined by the throat of the racket. In a pickleball version, the device is attached to a pickleball paddle from the side rather than in the throat.

Slot and Fastening System

The body defines one or more slots extending completely through its thickness from the first surface to the second surface. These slots accommodate straps, cords, or other fasteners for securing the device to the racket throat. The slots may be hollow interior cavities extending through the thickness of the spin device and may be curved, with curvature substantially aligning with or corresponding to the diameters of the surface edges.

Slots may be straight, curved, or arcuate in profile, with typical widths ranging from 1 mm to 2 mm to accommodate various strap thicknesses. Each slot may have a curved or arcuate profile rather than a straight profile, and may form hollow channels that traverse the thickness and are sized to receive a strap or other fastener.

Slots include radiused ends or chamfers to reduce strap wear and facilitate threading. The slots may be bounded by interior walls of the device and sized to permit passage of a chosen fastener, with radiused ends or chamfers to reduce wear on the fastener. The strap system comprises an elongate flexible member having a body with first and second ends. Another embodiment uses a velcro strap that has no eyelet.

When tensioned, friction between the strap body and opening retains the configuration, with additional securing via hook-and-loop, buckles, snaps, or magnetic fasteners. The first end can be folded back onto the body and secured by a coupling system such as hook-and-loop, a buckle, a snap, or a magnetic catch. The body can be formed from webbing, fabric, polymer, elastomer, leather, or a composite and can be non-elastic or elastic; its edges can be fused or stitched, and the region surrounding the opening can be reinforced to resist tearing.

Bearing Assembly and Rotation Mechanism

A bearing is positioned in the recess between the first and second surfaces, with its outer ring secured to the device body and inner ring providing contact surface for user interface. The bearing is at least partially seated within the recess of the fourth surface, with the recess receiving an outer surface or portion of the bearing and structured to align with the bearing or portions of the bearing surface.

The bearing enables relative rotation between the device and user object with minimal friction through rolling elements between the rings. The bearing may be a rolling element bearing including an outer ring and inner ring with respective raceways, with a plurality of balls located between the raceways so the inner and outer rings can rotate relative to one another with reduced friction.

The bearing includes a center portion disposed between the outer surface and inner surface, containing at least one ball and at least one cage configured to secure the balls in a certain plane while permitting ball rotation. The bearing may be referred to as a roller element bearing, though any type of bearing including plain bearings may be used.

A cage holds and spaces the balls at generally equal angular intervals and guides their motion during rotation. One or more sealing covers, such as shields or elastomeric seals, close the annular openings at one or both sides of the bearing to retain lubricant and inhibit ingress of dust, moisture, and other contaminants.

The center portion may include at least one cover or sealing disc on top and bottom surfaces to secure the ball and cage between the outer and inner rings. The balls within the center portion contact inside surfaces of both outer and inner rings, thereby permitting the rings to rotate with respect to each other.

The outer ring provides an outer surface that seats in the device recess through press-fit, snap-fit, or adhesive retention. The inner ring provides an inner surface configured for direct contact with user objects, with optional surface texturing, coatings, or elastomeric sleeves to enhance grip and prevent slippage. The normal force from the finger and the friction at the interface, which can be increased by surface texturing, a friction enhancing coating, or an elastomeric sleeve on the inner ring, prevent the inner ring from slipping relative to the finger.

Rotational Interface and Mechanics

When a user inserts a finger into the bearing opening, skin contact with the inner ring prevents relative rotation between ring and finger. With an object contacting the inner surface of the inner ring, the contact may inhibit or prevent rotation of the inner ring while the balls within the bearing permit rotation of the outer ring.

Applied torque to the racket transmits through the device to the outer ring, causing the device and racket to rotate as a unit around the stationary inner ring. Rolling elements permit this relative motion with minimal friction. The normal force from the finger and friction at the interface prevent the inner ring from slipping relative to the finger.

The rotation axis passes through the interior passage and is approximately perpendicular to the racket handle's longitudinal axis, typically approximately 90 degrees within ordinary tolerances. This orientation produces wheel-like rotation rather than baton-like spinning, creating different moment of inertia characteristics that enhance rotational stability and control.

Orienting the axis of rotation through the device's passage results in a mass distribution. This configuration increases the moment of inertia of the racket-handle system. The increased moment of inertia produces a more stable and sustained spin once initiated, resisting changes in rotational speed for improved control.

With the spin device and racket coupled together and the inner surface of the spin device coupled with the outer surface of the bearing outer ring, both components rotate together in response to rotational force applied to the racket. The racket may spin about an axis extending through the interior passage, with this axis substantially perpendicular to or at an abrupt angle to the axis extending through the length of the handle portion.

Materials and Construction

The device body may be formed from metals including stainless steel, aluminum, brass, and alloys thereof for applications requiring high mass, structural integrity, and enhanced rotational stability. Metal embodiments provide increased mass and moment of inertia, improving rotational stability and prolonging spin duration.

Metal components are manufactured through machining, stamping, investment casting, die casting, or CNC turning, with surface treatments including polishing, brushing, anodizing, plating, passivation, or coating for corrosion resistance, aesthetic finish, and tactile qualities. Metal embodiments can include knurling, grooves, or patterned surfaces to increase grip or alter aerodynamic behavior.

The spin device may include stiff or hard materials such as metal or polyvinyl chloride (PVC) to provide dimensional stability for the bearing recess and resistance to deformation under strap tension. In rigid embodiments, clips or retention rings may be integrated to inhibit decoupling from the racket.

Polymer embodiments utilize polyvinyl chloride (PVC) including rigid and flexible (plasticized) PVC, thermoplastic polyurethane (TPU), rubber compounds, or engineering plastics. These materials provide lightweight construction, impact absorption, enhanced grip characteristics, conformability to racket throat geometry, increased friction for secure seating, and vibration absorption.

In one embodiment, device bodies with polymeric embodiments can be produced by injection molding, extrusion, or blow molding, incorporating plasticizers, stabilizers, UV absorbers, colorants, flame retardants, or impact modifiers. Other suitable materials can be used.

Rubber materials include natural rubber or synthetic rubbers such as nitrile rubber (NBR), styrene-butadiene rubber (SBR), ethylene propylene diene monomer (EPDM), or silicone rubber. Rubber materials provide elevated frictional coefficients, impact damping, and comfortable tactile feedback with Shore durometer values typically ranging from Shore A 20 to 95.

Thermoplastic polyurethane (TPU) embodiments provide elastomeric flexibility, abrasion resistance, and chemical resistance. TPU materials are available over a broad hardness range with Shore A hardness values typically from 60 to 95 for grip surfaces, and are particularly suitable for overmolding onto harder cores.

Soft plastic embodiments comprise materials such as LDPE, LLDPE, polypropylene modified for softness, thermoplastic olefins (TPO), or other elastomeric polyolefins. These materials are readily molded, provide lightweight construction, and can be formulated with slip agents, impact modifiers, colorants, and stabilizers.

Composite constructions combine rigid cores with compliant outer layers, such as metal shells with elastomeric overmolding or polymer bodies with metal inserts for mass tuning. A rigid core formed of metal, rigid PVC, or hard plastic may concentrate mass at the periphery to increase angular momentum, while a softer outer layer provides tactile grip and impact protection.

Manufacturing and Assembly Methods

Device bodies are manufactured through injection molding for polymer components, CNC machining for metal parts, die casting for high-volume metal production, stamping, or additive manufacturing for prototyping and complex geometries. Bearing recesses require precision machining or molding to achieve required concentricity and surface finish.

Manufacturing methods for slots include stamping, laser cutting, waterjet cutting, die cutting, injection molding with core pins forming slot geometry, and machining. When polymer injection molding is used, slot geometry can be formed concurrently with the body and provided with reinforcing ribs to prevent deformation under load.

Assembly processes include bearing insertion through thermal assembly (differential expansion), mechanical pressing, snap-fit engagement, or adhesive retention depending on retention method. Adhesive retention utilizes anaerobic or epoxy formulations applied during controlled assembly procedures.

The inner edge diameter of both first and second surfaces is less than the corresponding outer edge diameter, creating an annular step that accommodates the bearing outer ring. Typical outer-to-inner diameter ratios range from 1.1:1 to 2.0:1, and more typically from 1.1 to 2.0 times the inner diameter, depending on bearing size and structural requirements.

The recess depth and diameter are precisely controlled to achieve proper bearing fit, with press-fit interference typically 0.01 mm to 0.1 mm for secure retention without race distortion.

Diameters of device edges may correspond to the size of user objects, with spin devices manufactured in different sizes to accommodate different ranges of user object sizes. Typical size classes include small, medium, and large configurations with interior passage diameters selected to match common finger dimensions.

The device can be produced in multiple size classes such as small (15 mm inner diameter), medium (17 mm inner diameter), and large (20 mm inner diameter). Size variation is achieved by altering the diameter of the interior passage and/or the inner ring of the bearing, or by providing removable sleeves or liners that reduce effective opening size.

Attachment and Mounting Systems

For temporary installation, the device couples to the racket throat through strap-based fastening systems. A flexible strap is threaded through a slot so that a portion emerges on the opposite side of the device. The strap is routed around a portion of the racket, such as throat legs, and brought back to the device where it can be tightened and fastened.

The straps may couple the spin device to the racket by being secured around each leg of the throat respectively. Since slots may be defined on substantially opposite portions of the spin device, straps may extend through slots and loop around each throat leg respectively, thereby tensioning the spin device across the throat. In another embodiment, the strap goes around the whole throat of the racket or paddle to accommodate the pickleball use.

In another configuration, particularly suited for paddles with a unified throat structure such as a pickleball paddle (FIG. 21), a single strap may be routed through a slot and around the entire circumference of the throat or handle junction. This strap encircles the entire frame to secure the device firmly in place, providing a universal attachment method that accommodates a wider range of sports equipment geometries.

When the strap is tensioned, it pulls the spin device against the inner surfaces of the racket throat and holds it in place. This tension may inhibit or prevent the spin device from moving during racket use. The straps pass through slots in the device body to route around throat portions.

Strap materials include woven or knit textiles, foam-backed fabrics, leather, synthetic polymers such as polyurethane or silicone, or combinations thereof. Strap thickness and width are selected to balance comfort, stability, and aesthetics, typically ranging from 10 mm to 120 mm in width and 1 mm to 1.5 mm in thickness.

Clamp-style attachments employ spring clips or mechanical clamps that engage racket frame surfaces through elastic or cam-actuated compression. These systems include protective pads to prevent frame damage and distribute clamping loads across adequate contact areas. A clamp-style clip comprises a U-shaped or C-shaped spring clip formed from resilient metal such as spring steel or from elastomeric polymer. The clip engages lateral walls of the racket frame or throat region and is held in place by elastic compressive force.

Magnetic coupling systems embed permanent magnets in the device body that attract to steel plates or opposing magnets mounted on the racket. When magnetic attachments are used, pairs of magnets or magnet assemblies are embedded, sewn, or adhered into complementary sites on components. Magnetic force is calibrated to provide secure retention during normal use while permitting intentional removal, typically ranging from 20N to 100N depending on device mass and application. Magnetic coupling strength is selected to permit separation under defined tensile load for safety purposes.

Snap-fit and bayonet connections utilize molded polymer features that deflect during installation and lock in position through mechanical interference or quarter-turn engagement. These systems include visual and tactile alignment aids for proper orientation. Threaded quick-release adapters comprise mating threaded studs and collars that engage by rotating to tighten and compress against the frame. A knurled outer surface or cam lever provides user-friendly actuation without tools.

For permanent installation, the device may be integrated during racket manufacturing through co-molding, insert molding, or adhesive bonding. Co-molded installations place the device body within the throat during frame fabrication, creating continuous structural integration without separate fasteners.

The spin device can be joined to the racket in a way not intended for removal by molding the device's outer surface directly to the inner surface of the racket throat. The racket manufacturer can place the spin device body in the throat opening and overmold or insert mold a compatible polymer.

Adhesive bonding utilizes structural adhesives such as epoxy or polyurethane formulations applied to prepared surfaces. Surface preparation includes cleaning, roughening, and primer application as required by adhesive specifications. Bonded installations provide permanent attachment suitable for original equipment applications.

Geometric Variations and Alternative Embodiments

While annular geometry is preferred, alternative embodiments include triangular, badge-shaped, or truncated configurations that accommodate various throat opening shapes. The spin device may include or be a triangular or badge shape, allowing it to sit in the bottom groove of triangular openings defined by racket throats.

Triangular embodiments conform to triangular throat openings with complementary peripheral contours and retention features such as snap tabs or bayonet lugs. The triangular shape may be equilateral, isosceles, or scalene depending on throat geometry, with rounded corners, chamfered edges, or decorative contours while retaining overall triangular planform.

Badge-shaped configurations include triangular profiles with rounded corners, chamfered or radiused edges, beveled faces, or decorative contours. The external surfaces may present face profiles that are flat, convex, concave, or sculpted with fins, ridges, or ornamental relief.

Truncated designs include flattened or chamfered segments that provide clearance for throat variations while maintaining bearing concentricity. The spin device body may have truncated geometry where one or more outer portions are shortened to form flats or chamfered segments, improving compatibility across different racket models.

The truncated body may be rotated or translated to seat the device near the bridge, centered, or closer to the handle-side apex without changing the bearing's position relative to the user's finger. This geometry improves compatibility across varied throat shapes and brands.

The device may define multiple slots with varying numbers, arrangements, and orientations. In some embodiments, the spin device may define three slots with straps configured to couple with or be seated in a variety of rackets at different locations.

With slots at different locations, users may desire to couple the spin device with the racket via straps passing through only selected slots depending on user preference or racket anatomy. Multiple slots can be uniformly spaced to balance the spin device during rotation or non-uniformly spaced to create designed imbalance.

The number of slots can range from a single slot to a plurality sufficient to achieve intended function. Angular spacing, radial length, and circumferential extent of each slot can be selected to control mass distribution, mechanical engagement, or other characteristics.

The concave outer surface may incorporate multiple discrete contact points rather than continuous surface contact. These contact points include convex lobes or projections that engage corresponding features on the throat inner surface, providing predictable load distribution and reduced stress concentration.

Contact point arrangements typically include three, four, or six discrete locations distributed symmetrically around the device periphery. Each contact point may include compliant elements such as elastomeric pads to accommodate manufacturing tolerances and provide vibration damping.

The convexity of outer edges allows multiple points of contact with the throat, which may provide more stable or secure coupling. Since many rackets include convex inner surfaces, the convexity of outer edges allows the device to be seated in various brands and variations of rackets. Opposing convexities of inner throat surfaces and outer device edges allow the spin device to easily sit within the throat, creating complementary geometry that nests together so opposing curvatures cradle each other and create multiple line or area contacts.

For strap-secured installations, the device is positioned against the throat inner surfaces with concave outer surface properly seated. Straps are threaded through slots, wrapped around throat portions, and tensioned to specified levels using integrated fastening mechanisms. The outer surface of the spin device may be in contact with the inner surface of the throat when coupled with the racket. The concave outer surface substantially aligns with the convex inner surface of the throat, with the throat at least partially seated in the spin device.

Visual alignment marks assist proper orientation during installation. Proper seating is verified through visual inspection and functional rotation testing to ensure the device remains stable during use. Permanent installations follow manufacturer-specific procedures including surface preparation, adhesive application, positioning, and curing under controlled conditions. Installation fixtures maintain alignment during bonding processes.

During operation, users insert fingers or tools into the central passage, engaging the bearing inner ring to provide rotational reference. A user object such as a finger may extend through the interior passage and interface with the inner ring of the bearing. The user object may be in contact with the inner surface of the bearing, with contact between the user object and inner bearing surface inhibiting or preventing rotation of the inner ring. The balls within the bearing center portion and outer ring permit rotation of the spin device and racket.

The spin device enhances rotation of the racket relative to a user object since it indirectly couples the racket with the bearing. Rotation of the racket or spin device may cause the other to rotate, enabling users to spin the racket in more than one way about multiple axes of rotation. Rotational speeds are limited by bearing capacity, user comfort, and safety considerations. Typical operational speeds range from slow deliberate rotation for grip adjustment to rapid spinning for entertainment or ritual purposes, generally not exceeding 300-500 RPM for handheld operation.

Devices are manufactured in multiple size classes to accommodate different finger dimensions and user preferences. The diameters of device edges may correspond to the size of user objects, with different sizes structured to correspond to different ranges of user object sizes such as Small, Medium, and Large. Size variation is achieved through different interior passage diameters, interchangeable bearing inner rings, or removable sleeve inserts that reduce effective opening size. A single product may be supplied with interchangeable inserts that convert the device between size classes. Each size class is chosen to correspond to common finger dimensions so users can insert fingers with snug yet comfortable fit while retaining control and smooth rotation. In some implementations, interchangeable inserts allow single devices to accommodate multiple size requirements.

Some embodiments incorporate adjustable mechanisms for fine-tuning fit and performance. These include threaded adjustment rings that modify effective inner diameter, removable compliance layers for contact pressure tuning, and modular weight inserts for moment of inertia adjustment. Retention and indexing features provide discrete positioning options, including detent mechanisms, magnetic positioning, or mechanical stops that define preferred angular orientations or insertion depths.

The device has concave outer surface whose curvature is complementary to convex inner surfaces of racket throats. When the device is placed in the throat, opposing curvatures nest together so the concave surface cradles the convex throat surfaces, creating multiple line or area contacts that self-center the device.

User Safety Features Design features prioritize user safety through rounded edges, smooth surface transitions, and elimination of pinch points at the rotating interface. The interior passage is dimensioned so users can place body parts into it comfortably, with edges that can be rounded or chamfered to avoid discomfort during use.

Bearing selection ensures adequate load capacity for expected operational forces while maintaining smooth operation. Material selection considers biocompatibility for skin contact applications, with non-toxic surface treatments and finishes. Retention mechanisms are designed to prevent accidental disengagement during vigorous activity while permitting intentional removal when required. Emergency stop capabilities include friction-increasing mechanisms, manual braking features, or breakaway connections.

Rotational performance is optimized through bearing preload adjustment, lubrication selection, and mass distribution tuning. Proper preload eliminates excess play while maintaining smooth rotation, typically achieved through controlled interference fits or spring washers.

Lubrication systems include sealed bearings with lifetime lubrication, re-greaseable bearings with service intervals, or dry lubrication systems for minimal maintenance requirements. Environmental sealing protects internal components from moisture and contamination. Balance optimization includes dynamic balancing of rotating assemblies, strategic mass placement, and geometric symmetry to minimize vibration and ensure smooth operation across the full rotational speed range.

Metal components receive surface treatments including anodizing for aluminum parts, passivation for stainless steel, electroplating for enhanced corrosion resistance, or coating application for specific friction characteristics. These treatments include anodizing, passivation, electrochemical polishing, powder coating, painting, chemical conversion coatings, shot peening, and mechanical polishing.

Surface treatments tailor corrosion resistance, surface friction, reflectivity, electrical conductivity, or aesthetic appearance. Wall thicknesses, cross-sectional geometries, and metal selection are chosen according to load-bearing, thermal, and environmental requirements. Bearing contact surfaces receive controlled surface finishes to optimize friction and wear characteristics, including polishing, knurling, or application of dry film lubricants for enhanced user interface performance.

Polymer components may include texturing, UV stabilizers, and colorants applied during manufacturing. Surface treatments can include textured surfaces, UV-resistant additives, and aesthetic colorants integrated during the molding process. For applications requiring specific surface characteristics, polymer parts may receive secondary treatments such as chemical etching, mechanical texturing, or coating application to achieve desired tactile or visual properties.

Sport-Specific Adaptations and Applications

While described primarily for tennis applications, the device adapts to other racket sports including pickleball, padel, squash, racquetball, paddleball, ping pong, badminton, frontenis, crossminton, platform tennis, and basque pelota. The term racket encompasses both stringed rackets and paddle-style implements found in these sports.

Sport-specific features include modified attachment methods for different frame materials and geometries, adjusted mass distributions for sport-appropriate rotational characteristics, and specialized surface treatments for various environmental conditions. Dimensional scaling accommodates different racket throat geometries and player requirements across sports. The device can be secured to the throat, yoke, bridge, or analogous junction between handle and head of the implement. Regulatory compliance considerations address sport governing body equipment regulations, with removable configurations typically providing broader acceptance than permanently integrated designs.

Multi-Axis Rotation Systems

Advanced embodiments incorporate multiple degrees of rotational freedom through spherical bearings, universal joints, or gimbal arrangements. The bearing can be configured to support radial loads and, where required, carry axial (thrust) loads through combined radial-thrust bearing arrangements. Multi-axis systems include additional bearing assemblies, more complex mounting arrangements, and enhanced user interface features to accommodate increased functionality without compromising basic operational simplicity. A universal joint or constant-velocity joint connecting the spin device to an axle fixed to the racket comprises yokes and cross-pins, enabling rotational transmission around one axis while permitting pivoting around a second axis.

Electronic embodiments incorporate sensors, motors, or control systems within the device structure. Sensor applications include rotation monitoring, usage tracking, or performance analysis capabilities with wireless data transmission. A sealed cavity within the device body can accommodate batteries, LEDs, gyroscopes, accelerometers, or other components, with electrical contacts routed to mating pads or wireless transmitters. Sealing is provided using gasketing and potting compounds. Motorized versions provide powered rotation for training applications, demonstration purposes, or enhanced entertainment value. Power systems include rechargeable batteries, wireless power transfer, or external power connections with appropriate safety measures. Control interfaces include manual switches, automatic activation, or remote control capability depending on application requirements and user preferences.

Materials and surface treatments are selected for resistance to moisture, temperature variations, UV exposure, and chemical contact from sweat and cleaning products. Sealed bearing designs prevent contamination while maintaining long-term performance. Corrosion resistance measures include appropriate material selection, protective coatings, and design features that prevent moisture accumulation in critical areas. Drainage features and ventilation passages facilitate cleaning and drying.

Training applications include grip transition exercises, hand-eye coordination development, and pre-serve routine establishment. Consistent rotation characteristics support muscle memory development and routine standardization. Practice benefits include stress reduction through fidgeting motion, focus enhancement during concentration exercises, and entertainment value during downtime or social interaction.

The device supports pre-point rituals and focus techniques that enhance competitive mental preparation. Controlled rotation provides calming repetitive motion that reduces anxiety and promotes concentration. Entertainment applications include skill demonstrations, social interaction facilitation, and general enjoyment of smooth mechanical motion that appeals to users across age groups and skill levels.

Customization features include color variations, surface textures, personalized engravings, performance tuning options, and accessory compatibility for enhanced functionality or aesthetic appeal. Material combinations can be selected based on user preferences and performance requirements.