The invention concerns a bladder (1) for an inflatable ball, in particular a soccer ball. The bladder (1) comprises at least two planar reinforcing surfaces (10) extending in the interior of the bladder (1) and at least one electronic device (30) arranged within the bladder (1) and maintained in a predetermined position by the planar reinforcing surfaces (10).

A variable-weight playball whose outer casing (10) is formed of liquid-impervious, flexible material, having closable port (14) therein. Confined within the casing (10) is a compressible body (11) having the same configuration which depends on whether the ball is spherical or in some other shape. The body is formed of low-density, open-cell, flexible foam plastic material having sponge-like properties. To impart heft to the ball, water is introduced through the port (14) into the body and absorbed thereby, the port then being closed to retain the water. To thereafter lighten the ball, the port is opened and the ball is squeezed to discharge water through the port until the ball has the desired reduced weight, after which the port is closed. The casing may be contoured, printed or otherwise arranged so that the ball simulates the head of a humanoid or animal-like character having a mouth. The port (26) of the casing is integrated with the mouth of the character so that when water is added to the ball, it is seemingly introduced through the mouth.

A sewn ball includes an inner tube and a housing (4). The inner tube includes a tube body (1), a yarn layer (2) and a rubber layer (3), wherein the yarn layer is attached to an external surface of the tube body, the rubber layer is attached to an external surface of the yarn layer and is then vulcanized, in such a manner that a rubber raw material of the rubber layer permeates through yarn gaps of the yarn layer, so as to integrate the tube body, the yarn layer with the rubber layer. The housing (4) wraps around and is attached to the inner tube (1). The sewn ball provided by the present invention has excellent bouncing ability, high strength, good durability, small circumferential error, and excellent balance and flight stability.

Exercise device (1) comprising an exercise ball (10) and a cover (20) housing and completely surrounding this ball (10); the cover being designed to couple, in use, in a substantially form-fitting manner to the outer surface of the shell (11) of the exercise ball (10) and being provided with a respective closing device (25) that can be selectively opened to allow the exercise ball (10) to be inserted into and extracted from it.

The ball for a ball game of the invention includes a fabric layer (1) having a spherical 12-hedron where twelve right pentagonal fabric pieces (2) arc sewn together. The marginal edges of the fabric piece being folded by 90 degrees, and the marginal edges are sewn together with a sewing machine. The fabric layer is then reversed through cross-like slits (5a, 5b) formed in the fabric layer in a location opposite to a valve opening (5) (also formed in the fabric layer) in such a manner that the marginal edges are located on an inner side of the fabric layer. After the bladder is accommodated within the fabric layer through the closure hole (5), the hole (5) is closed by a patch. Onto a surface of the fabric layer, there is adhered the panels. Thereby, the ball for a ball game having no unevenness and soft feeling is attained.

Ein ballartiges, kugelförmiges Sportgerät, insbesondere ein Fußball, mit einer über eine Ventileinrichtung aufpumpbaren flexiblen Blase, die von einer Ballhülle umgeben ist, wobei diametral bezüglich des Kugelmittelpunkts der Ventileinrichtung gegenüber liegend eine Ausgleichsmasse angeordnet ist, die die gleiche Masse wie die Ventileinrichtung aufweist, ist dadurch gekennzeichnet, dass zusätzlich zur Ausgleichsmasse für die Ventileinrichtung mindestens ein Paar von bezüglich des Kugelmittelpunkts diametral einander gegenüber liegend angeordneten weiteren, ungefähr gleich schweren Ausgleichsmassen vorgesehen ist. Vorzugsweise sind noch mehr Ausgleichsmassen jeweils paarweise diametral einander bezüglich des Kugelmittelpunkts gegenüber liegend angeordnet, wobei zusammen mit der Ausgleichsmasse für die Ventileinrichtung insgesamt n-1 Ausgleichsmassen vorgesehen sind, welche die Positionen m1, m2, ... , mn-1 auf einer gedachten Kugeloberfläche einnehmen, und wobei n eine gerade natürliche Zahl und n ≥ 4. Damit wird es dem Ballspieler ermöglicht, leicht und unkompliziert erheblich mehr Präzision in seinen Schuss, vor allem in einen Weitschuss zu legen und somit eine höhere Trefferwahrscheinlichkeit zu generieren.