Patent Description:
In this specification, the term "lattice" is intended to refer to lattice or grid structures which are thin in relation to their lengths and breadths and which are perforated by a series of openings of a variety of shapes.

In this specification, the term "ball" must be interpreted sufficiently broadly to include a reference to a ball, sphere, shuttlecock or the like, which is configured to be struck by a bat in a "bat and ball" game.

Plastics bats having unstressed perforated ball-striking heads, are known. Such bats are considered a cheaper and more robust alternative to conventional strung racquets or solid faced bats. The present invention is not concerned with bats having heads comprising a single solid panel which may or may not be partially perforated such as solid wooden bats, nor is it concerned with bats having stressed striking surfaces such as strung squash or tennis racquets.

It is also not concerned with padel bats having ball-striking surfaces made from thin glass fibre reinforced membranes having a thickness of about <NUM>, which are stretched across outer surfaces of frames of such bats. Such padel bats are typically filled with plastic foam material and perforated but do not have significant surface ribbing to impart spin to a ball.

An advantage of the use of rigid-faced bats is the reduced level of the trampoline or spring like effect of strung racquets upon impact with a ball which generates more speed off the face of the racquet causing the ball to fly further and faster necessitating the use of a larger playing area. The rise in popularity of relatively new bat and ball games using rigid-faced bats, such as Paddleball, Paddle tennis, Pickleball and Padel on smaller courts is evidence of a swing to smaller courts at the expense of the game of tennis played on conventional larger size courts. Many such bats are heavier and shorter in length than tennis racquets to reduce the bat stroke and ball speed for the smaller courts they are used on.

An important commercial advantage of plastics bats is that they are simple and quick to produce, for example, in an injection moulding process and considerably cheaper than strung tennis racquets or bats made from solid wood.

One of the problems with moulded plastic bats has been the fact that many such bats have not been able to reproduce the sweet and solid impact feel experienced with solid wooden bats, tennis racquets or paddle tennis bats which exhibit excellent impact feel.

Bats having unstressed perforated ball-striking heads need to be appropriately weighted for the balls they are to be used with and offer also low air resistance. Such bats should be of a weight which is easy and practical for players to use and wield for any particular type of game.

For a good ball-striking feel, such bats need to be relatively rigid and offer minimal uncomfortable vibrations upon impact with a ball. The rigidity of the ball-striking head is derived from its thickness, the stiffness of its material and its structural design but it is an important design consideration that this is not achieved at the expense of increased mass of the bat or decreased striking head area. Thicker ball-striking heads tend to dampen and reduce impact vibration. It is therefore advantageous for the ball-striking head of a bat to have an adequate thickness which reduces vibration upon impact with a ball and renders the head sufficiently rigid, without making the bat excessively heavy.

<CIT> discloses a bat for playing ball games comprising a handle and a ball-striking head having a monolithic structure comprising a pair of spaced apart outer lattices which define rigid, unstressed ball-striking surfaces and a plurality of discrete internal struts which are integrally moulded with the lattices so as to extend between the lattices.

It is an object of the present invention to provide an appropriately weighted bat having a perforated ball-striking head which provides a solid low vibration impact feel combined with low air resistance and an acceptable striking head area for striking balls.

According to the invention there is provided a plastics bat comprising the features of claim <NUM>. The plastics bat includes a handle and a ball-striking head for striking resilient balls, the ball-striking head having a monocoque construction and including:.

Each of the first and second lattices may have a unitary monolithic structure.

In a first embodiment of the invention, each of the first and second lattice structures may comprise a number of spaced intersecting laths arranged in an open grid pattern wherein openings are defined between the intersecting laths.

In a second embodiment of the invention, each of the first and second lattice structures may comprise a distributed network of alternating webs and unobstructed openings.

The peripheral support structure of the ball-striking head of the bat may comprise an outer ring frame to which the lattice structures are connected.

The lattice structures may be fixedly connected to the outer ring frame along peripheral edge regions of the lattice structures.

The lattice structures and the outer frame may form a continuous load-carrying outer skin surrounding the unobstructed internal space.

The ball-striking head of the bat has a monocoque construction wherein the lattice structures together with the outer ring frame, forms an outer skin surrounding the hollow internal space. The ball-striking head of the bat forms a true monocoque system wherein the internal space defined between the lattice structures is characterised by the absence of any load-carrying support structures. As such, the outer skin comprising the lattice structures and the outer frame, carries the compressive forces and loads applied to the ball-striking head when a ball is struck by the ball-striking surfaces of the lattice structures.

According to a second aspect of the invention, there is provided a bat and ball kit comprising the plastics bat as defined and described hereinabove; and a resilient ball having a diameter of between <NUM> and <NUM> and a weight of between <NUM> and <NUM>.

Further features of the invention are described hereinafter by way of examples of the invention with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings:.

With reference to <FIG> of the drawings, a first embodiment of a bat for playing ball games, which is not in accordance with the invention, is designated generally by the reference numeral <NUM>. The bat is injection moulded of plastics material and is specifically adapted for playing ball games in playing areas smaller than traditional tennis courts. The bat <NUM> comprises, broadly, a handle <NUM> and a ball-striking head <NUM> for striking resilient balls.

The ball-striking head <NUM> has a symmetrical configuration comprising a peripheral support structure in the form of a rigid outer ring frame <NUM> which is injection moulded integrally with the handle <NUM>, a first discrete single lattice structure <NUM> comprising a single lattice which is connected along an outer peripheral region of the lattice structure to a first side of the outer ring frame <NUM> and a second discrete lattice single structure <NUM> comprising a single planar lattice which is connected along an outer peripheral region of the lattice structure to an opposite second side of the outer ring frame <NUM>.

The lattice structures <NUM>, <NUM> are unstressed and of polypropylene, while the outer ring frame <NUM> is of acrylonitrile butadiene styrene (ABS) material.

The first lattice structure <NUM> is in the form of a semi-rigid single planar lattice element having an open perforated monolithic unitary construction, comprising a plurality of intersecting laths <NUM> which are arranged in an open grid pattern. The laths <NUM> extend longitudinally and laterally, intersecting one another at right angles, with openings <NUM> being defined between the laths. The lattice structure <NUM> includes a pair of spaced annular locating formations <NUM> and <NUM> which extend circumferentially around the laths <NUM> and which define back-to-back annular locating grooves <NUM> between them. Circumferentially spaced holes <NUM> are defined in a bridging base section <NUM> of the lattice structure defining the grooves, the purpose of which will be explained hereinbelow.

The second lattice structure <NUM> is identical to the first lattice structure <NUM> and is in the form of a semi-rigid single planar lattice element having an open perforated monolithic unitary construction, comprising a plurality of intersecting laths <NUM> which are arranged in an open grid pattern. The laths extend longitudinally and laterally, intersecting one another at right angles, with openings <NUM> being defined between the laths. The lattice structure <NUM> includes a pair of spaced annular locating formations <NUM> and <NUM> which extend circumferentially around the laths <NUM> and which define back-to-back annular locating grooves <NUM> between them. Circumferentially spaced holes <NUM> are defined in a bridging base section <NUM> of the lattice structure defining the grooves, the purpose of which will be explained hereinbelow.

The lattice structures <NUM> and <NUM> are securely connected to opposite sides of the outer ring frame <NUM> so as to define rigid unstressed ball-striking faces <NUM> and <NUM>, respectively. In the assembled condition of the bat, the lattice structures <NUM> and <NUM> are spaced apart with opposing inner sides of the lattice structures <NUM>, <NUM> defining an internal space <NUM> between them. The internal space is characterised by the absence of any internal load-bearing support structures. In this example, the internal space is hollow and unobstructed.

The outer ring frame <NUM> comprises a rigid annular wall <NUM> having a first outer edge <NUM> which is received within the groove <NUM> of the lattice structure <NUM> and a second outer edge <NUM> which is received within the groove <NUM> of the lattice structure <NUM> for locating the lattice structures <NUM> and <NUM> with respect to the outer frame <NUM>. The outer edges <NUM>, <NUM> of the wall <NUM> each define a plurality of spaced locating studs <NUM> projecting outwardly from the peripheral edges <NUM>, <NUM>. Each of the studs is located in one of the locating holes <NUM>. The studs <NUM> provide weld pegs for ultrasonic spot welding <NUM> of the lattice structures <NUM>, <NUM> to the outer frame <NUM>. As such, the studs are melted and fused to the lattice structures in an ultrasonic welding process. In order to enhance the connection of the lattice structures to the outer frame, the lattice structures may be additionally bonded to the outer frame using a suitable adhesive.

With reference to <FIG> of the drawings, there is provided a second embodiment of the bat in accordance with the invention, designated generally by the reference numeral <NUM>. The bat <NUM> is similar to the bat <NUM> with a difference being that the single lattice structures <NUM> and <NUM> are replaced by double lattice structures. In <FIG> of the drawings, those features of the bat <NUM> that are the same as and/or similar to those of the bat <NUM>, are designated by the same and/or similar reference numerals. As such, the bat <NUM> comprises, broadly, a ball-striking head <NUM> having a symmetrical configuration comprising a peripheral support structure in the form of an outer ring frame <NUM> which is integrally moulded with a handle <NUM>, a discrete first double lattice structure <NUM> and a discrete second double lattice structure <NUM> which are rigidly connected at outer peripheral regions thereof to opposite sides of the outer ring frame in the same manner in which the lattice structures <NUM> and <NUM> are connected to the outer ring frame <NUM> of the bat <NUM>.

Each double lattice structure <NUM>,<NUM> has a plastics moulded unitary monolithic construction and comprises a pair of spaced single planar inner and outer lattice elements <NUM>, <NUM> supported by internal struts. A further difference between the bat <NUM> and the bat <NUM>, is that the lattice elements <NUM>, <NUM> each comprise a connected network of alternating webs <NUM> and unobstructed openings <NUM>. As such, each lattice structure <NUM>, <NUM> includes the inner lattice element <NUM> and the outer lattice element <NUM> and a plurality of internal struts <NUM> which are integrally moulded with the lattice elements so as to extend between the lattice elements. Outer sides of the outer lattice elements <NUM> of each double lattice structure <NUM>, <NUM> define rigid ball-striking faces <NUM>, <NUM>, respectively. The webs <NUM> each define four triangular apertures <NUM> providing escape paths for air which is compressed between a ball and the outer lattice elements when the ball is struck by the bat, for noise attenuation purposes.

The double lattice structures <NUM>, <NUM> each include a pair of spaced annular locating formations <NUM> and <NUM> which extend circumferentially around the network of webs and openings and which define back-to-back annular grooves <NUM> between them. Outer edges <NUM>, <NUM> of the wall <NUM> of the outer frame are received in the inner grooves with the studs <NUM> being received within the holes <NUM> defined in the bridging base sections <NUM> of the lattice structures and secured via an ultrasonic welding process in the same manner as for the lattice structures <NUM>, <NUM> of the bat <NUM>.

As for the bat <NUM>, the double lattice structures <NUM>, <NUM> of the bat <NUM> are spaced apart so as to define a hollow unobstructed internal space <NUM> between them.

The ball-striking heads <NUM>, <NUM> of the bats <NUM>, <NUM>, respectively, have a monocoque construction wherein the lattice structures together with the outer ring frames thereof, form a continuous outer skin surrounding the hollow internal space <NUM>,<NUM>. The ball-striking heads <NUM>,<NUM> thus form a true monocoque system wherein the internal space defined between the lattice structures is characterised by the absence of any load-carrying support structures. As such, the outer skin comprising the lattice structures and the outer frame carries the compressive forces and loads applied to the ball-striking head when a ball is struck by the ball-striking surfaces of the lattice structures. The monocoque construction of the ball-striking head imparts stiffness and strength to the ball-striking head, allowing the ball-striking head to have a desirable lightweight construction which in turn allows the construction of a relatively thick ball-striking head which enhances overall rigidity of the ball-striking head.

In addition, the monocoque construction of the ball-striking head serves to absorb vibration forces imparted to the bat when a ball is struck by the bat by transmitting the vibration forces throughout the outer skin of the ball-striking head. In vibration tests conducted on the bats in accordance with the invention, by the Applicant, it was established that the monocoque design of the ball-striking head significantly reduces vibration transmitted via the ball-striking head to the handle. In the vibration acceleration tests conducted by PACE-WOOD BENCHMARK - Acoustic engineers for the Applicant, impact vibration transmitted to the handle of the bat, expressed in vibration acceleration in metres/second<NUM> (m/s<NUM>), was measured at levels below <NUM>/s<NUM> which provides the bats with a comfortable impact feel comparable to good quality strung tennis racquets.

The bats <NUM>, <NUM> are designed for use with resilient balls having a bounce of at least <NUM> when subjected to a drop test wherein such balls are dropped from a height of <NUM> inches (<NUM>) onto a rigid, hard horizontal, solid and flat impact surface. More specifically, the bats are designed for use with resilient balls having a diameter of between <NUM> and <NUM> and a weight of between <NUM> and <NUM>. The invention extends to a bat and ball kit including one or both of the bats <NUM>,<NUM> and a resilient ball as described hereinabove.

Claim 1:
A plastics bat (<NUM>) including a handle (<NUM>) and a ball-striking head (<NUM>) for striking resilient balls, the ball-striking head having a monocoque construction and including:
a first discrete unstressed plastics lattice structure (<NUM>) defining a first ball-striking surface of the bat (<NUM>);
a second discrete unstressed plastics lattice structure (<NUM>) defining a second ball-striking surface of the bat (<NUM>); and
at least one peripheral support structure (<NUM>),
wherein
the lattice structures are connected to opposite sides of the peripheral support structure at outer peripheral regions of the lattice structures in a spaced apart arrangement wherein an internal space (<NUM>) is defined between the first and second lattice structures absent of any load-bearing internal support structures,
characterized in that each of the first and second lattice structures is in the form of a double lattice comprising a pair of spaced planar lattice elements supported by internal struts.