A hollow, tube-shaped ball bat having a damping core made a tube of brass wrapped in a resilient sleeve made from polystyrene closed cell foam is disclosed. The damping core is forcibly inserted into the interior of the hollow bat by compressing the resilient sleeve. When assembled into the bat, the resilient sleeve is under great compression. Furthermore, the tubing wall forming the bat is relatively thin to transmit the impact of the ball to the resilient sleeve. The processes to obtain a damped core bat are also disclosed. A tube is provided which is swaged to form a barrel portion, a tapered portion, and a handle portion. The resilient sleeve is compressed and inserted into the open top of the tube. Alternatively, the damping core is inserted into the tube and the inner damper which has a tube structure is expanded radially to compress the resilient sleeve between it and the tube wall. The top of the tube is covered by a cap and the bottom of the tube is enclosed with a knob. The ball bat is made from a high tensile aluminum alloy or a high strength aircraft alloy.
Vibrations of the stylus (4) of a measuring probe (1) mounted on a machine, and which are transmitted to the probe stylus via the machine quill and probe body, are reduced or eliminated by a vibration damping means positioned within a cavity of the stylus. FIG. 2 illustrates a first embodiment in which the vibration damping means is a unconstrained rubber cylinder (16), in a hollow cartridge (12) connected to the stylus at its tip. Alternatively a dynamic vibration absorber can be used.
A lightweight shaft 22 of generally tubular configuration, for with a golf club 20, is formed with a first layer 34 of a non-metallic composite material of a given density including graphite fibers 86 and cured epoxy resin 86. A second layer 38 of the shaft 22 is composed of a two foam half-forms 124, or a foam full-form 142, having a density which is lower than the given density and which are located around at least a portion of the length of the first layer 34. A third layer 40 of the shaft 22 is also composed of a non-metallic composite material including graphite fibers 86 and cured epoxy resin 86 which is located around the second layer 38 of the shaft 22. A portion of the third layer 38 is also located about the first layer 34 at a tip end 30 of the shaft 22.
A thin wall tubular bat, particularly for softball, has a constant barrel diameter and an internal tubular insert spaced from the barrel with a shear stress transmitting elastomeric layer sandwiched between the barrel and insert so that the insert reinforces the barrel to reduce denting which would otherwise occur as the elastomer efficiently transfers stress to the insert and stores and releases energy during impact of the bat with a ball.
A tube-shaped element that can be inserted within the hollow barrel portion of an aluminum softball bat will provide damping and spring characteristics to the softball bat with improved life. This tube-shaped element is made from heat-treated metals and formed with a top and bottom diameter substantially equivalent to the internal diameter of the softball bat and with a central portion somewhat larger in diameter. A series of holes is drilled along the periphery of the top and bottom ends and then a series of slits is cut longitudinally along the length of the middle portion, each slit travelling from a hole in the top end to a similar hole in the bottom end. These slits permit the element to be compressed so as to fit within the hollow-hitting portion of the softball bat. A plastic coating may be placed on the tube-shaped element or a foam may be foamed within the hollow portion in order to deaden the sounds.
An improved striking implement is provided. The striking implement includes an essentially cylindrical metal shaft having a central cavity. A massive load is disposed within the central cavity at some distance from the upper end of the implement. When the striking implement is swung to contact an object to be struck, the load imparts a secondary impact, additive to the primary impact of the shaft upon the struck object, thereby increasing the forcefulness of the blow as a whole. Appropriate choice of suspension means for the load and situating of the load and suspension means optimize the additional energy imparted to the struck object. In the case in which the implement is a sports bat for striking a ball such as a softball or baseball, significant increase in the speed with which a hit ball leaves the bat, and thus meaningful athletic performance enhancement, is attainable by using the cavity-loaded bat illustrated as an embodiment of the invention.
