a first embodiment of the weight training apparatus 10 is shown in fig1 . the apparatus or trainer 10 is a small , flexible crescent shaped tube 2 having an inner compartment 4 filled with a material or materials which has the effect of being shock absorbing . the trainer tube 2 is formed generally from a polymer material such as a substantially rigid , but slightly flexible material such as plastic or elastomeric material . some types of plastics which may be used to make the tube include but are not limited to pet ( pete ), polyethylene terephthalate , hdpe , high - density polyethylene , pvc , polyvinyl chloride , ldpe , low - density polyethylene , pp , polypropylene , and ps , polystyrene . the tube 2 includes a sidewall defined by an outer wall 12 and an inner wall 14 being radially spaced apart and defined substantially concentric about a main axis a . the inner wall 14 has a diameter which defines a central passage 6 through the tube 2 about the axis a . the outer and inner walls 12 , 14 have an axial length l extending between opposing ends of the tube 2 . the axial length l between the ends of the tube 2 may be between 6 . 3 cm ( 2 . 5 in .) and 8 . 9 cm ( 3 . 5 in .) and is preferably about 7 . 6 cm ( 3 . 0 in .) in length . through the sidewall and along the length l of the tube 2 between the opposing ends of the tube 2 is an axial opening 16 which also extends radially entirely through the sidewall defined by the spaced apart outer and inner walls 12 , 14 . the axial opening 16 provides a radial passage through the tube 2 that communicates with the central passage 6 . on either side of the axial opening 16 are endwalls 8 which extend radially between the inner and outer walls 12 , 14 on either side of the axial opening , essentially defining the axial opening 16 , and also extend the length l of the tube 2 to the ends of the tube 2 . the substantially circumferential space defined between the outer and inner walls 12 , 14 as well as the end walls 8 forms an inner compartment 4 as shown in fig1 . where a desired material is to be maintained within the inner compartment 4 of the tube 2 a first sealed cap or stopper 20 is secured to one end of the tube 2 using glue or adhesive or a mechanical securing means such as threads or an engaging snap fit as known in the art . the end cap or stopper 20 may be of a similar elastomeric material as the trainer 10 with an axial opening 22 , and extension walls 24 to insert into the inner compartment 4 to secure the stopper 20 to the tube 2 . as shown in fig2 , the inner compartment 4 may be filled with a desired solid or semi - solid material such as a shock absorbing material 18 including but not limited to rubber , foam , plastic or metal beads or other elastically resilient polymers or materials that facilitate the absorption of any vibration of the sports implement on contact with the hitting of a ball or other sports object . it is to be appreciated that the desired material in the compartment 4 may even be a fluid such as oil or gel or some other fluid having a desired viscosity to facilitate the absorption of force transmitted through the tube 2 . a second cap or stopper 21 is provided at the opposing end of the tube 2 to entirely enclose and seal the desired material within the compartment 4 . the second stopper 21 may be glued , threaded or attached to the end of the tube 2 in any known manner . alternatively , the tube 2 may be formed through a mold or other manufacturing process having a first end sealed , thereby forming a tubular container . the inner compartment 4 may be filled and sealed using a single stopper 20 or end cap . a top plane view of the trainer 10 is shown in fig3 and a front elevation view is shown in fig4 . the outer wall 12 of the tube 2 has an outer diameter d that is greater than an inner diameter d of the inner wall 14 to define the compartment 4 . the outer diameter d in a preferred embodiment having a length of 2 . 89 cm ( 1 . 14 in ) but may be at a dimension of for example from 2 . 54 cm ( 1 . 0 in .) to 3 . 81 cm ( 1 . 5 in .) with the overall dimension of the length l of the tube and the diameter d dependent upon the desired weight of the apparatus . as an example , for an outer diameter of 2 . 89 cm ( 1 . 14 in .) and the appropriate inner diameter to accommodate for example a golf club , a length l of 7 . 6 cm ( 3 in .) would provide a weight with a filled cavity of approximately 4 . 5 oz ., roughly 1 . 5 oz . for every inch of length . the inner diameter d is generally sized to frictionally engage with a desired size of sports implement on which the apparatus 10 is to be supported . in a first embodiment of the present invention the inner diameter d is further sized to define the central passage 6 which accommodates the tubular dimensions of a golf club as shown in fig5 . standard golf club shaft diameters are 1 . 5 cm ( 0 . 600 in . )″ at butt and 0 . 85 cm ( 0 . 335 ″) at tip for woods and 0 . 94 cm ( 0 . 370 ″) at tip for irons . a preferred dimension for the inner diameter d of the inner wall 14 in this embodiment would be approximately the same or slightly smaller than the above noted shaft tip diameters so that there is a slight frictional gripping of the inner wall 14 about the club shaft to facilitate the trainer 10 being maintained on the club shaft . other sports implements can of course have different diameters leading to different inner diameters d for various embodiments of the invention . the axial opening 16 which as discussed above extends the length l of the trainer 10 and has a width w which is generally sized to be slightly smaller than the shaft diameter of for instance a golf club . because the tube 2 has some inherent flexibility in the plastic or elastomeric nature of the tube material , the tube 2 including the outer and inner sidewalls 12 , 14 are permitted some slight flex in a radial manner about the main axis a which allows the width w of the axial opening 16 to be biased into a slightly enlarged width w to allow for passage of for example the golf club shaft through the axial opening 16 . in other words , the flexible nature and relatively loose material in the compartment 4 of the trainer 10 allows for the width w of the cutout portion 16 to expand from a first closed position as shown in fig5 a to an open position due to a force on the endwalls 8 by for example the shaft 28 of a golf club 30 , or by a user manually forcing the endwalls 8 slightly farther apart , as sown in fig5 b and a return to the closed position adhering around the shaft 28 of a golf club 30 in fig5 c . in this manner the trainer 10 is attached to the golf club 30 by simply aligning the axial opening 16 of the trainer 10 along the shaft 28 of the club at a point above the golf head 32 and applying pressure on the trainer 10 to force the axial opening 16 to open until the shaft 28 of the golf club 30 slips through the axial opening and into axial alignment with the trainer 10 inside the central passage 6 . the inner wall 14 may be dimpled , ridged or have a plurality of protrusions 26 creating frictional points to better adhere the trainer 10 to the smooth metallic surface of a golf club 30 or other sports implement and prevent the trainer 10 from sliding up or down the shaft 28 . the trainer 10 is also easily removed by grasping around the trainer 10 and the shaft 28 and pulling the trainer 10 away from the shaft 28 . the cutout portion 16 separates and the shaft 28 is pulled away from the inner wall 14 and out through the cutout portion 16 . no tools or external devices are necessary to attach or remove the trainer 10 from a sports implement . the inner cavity 4 is substantially filled with a desired material such as a loose , uncompacted shock dampening or absorbing material 18 providing weight and force dissipating effects to the trainer 10 . the trainer 10 may be of different length and dimensions to accommodate a larger amount of desired material 18 and thereby increase the overall weight of the trainer 10 . a series of trainers may be provided at different weights to assist in a training program of lighter to heavier weights in order to gradually train and build muscle strength and memory . the desired material 18 may be for example loose metal shot or bearings that dampen vibrations by dissipating and damping the torsional and axial shaft forces caused by the impact of the club head 34 hitting the ball . the position of the weight training apparatus 10 may be at different intermediate positions along the shaft 28 of the golf club 30 and with a very tight tolerance between the outer surface of the shaft 28 and the inner wall 14 of the trainer 10 , essentially having no space or play therebetween , providing for swinging of the club 30 in a balanced manner thereby allowing for a normal swing as shown in fig6 a - 6e . muscle acuity and tone is built up as the club is swung back normally as shown in fig6 a . the club 30 even with the additional weight of the trainer 10 can still be held and aligned over the golf ball 34 as shown in fig6 b without a drag or pull on the club 30 that may be caused by an extension of a weight training device away from the shaft as shown in some examples of the prior art . contact with the golf ball 34 is made in a smooth even manner with any vibrations caused from the impact of club head 32 to the ball dissipated by the trainer 10 and the desired material 18 . in examples of the prior art , a club cannot be swung in a normal even manner and the weight training device vibrates unevenly to the shaft causing pain within the palms of the golfer &# 39 ; s hands as the club head 32 contacts a golf ball . with the weight training device 10 of the present invention the ball may be contacted and follow through of swing is completed in a smooth even manner as shown in fig6 d and fig6 e . the smoothness and normalcy of swinging the club with the training device 10 builds muscle memory and repetitive practice builds strength . by removing the weight training device 10 , the club speed is increased as the club is still swung with the same smoothness but is lighter without the increased weight of the trainer 10 . the dimensions of the weight trainer 10 , outer and inner walls 12 , 14 and the compartment 4 may be modified to accommodate the attachment of the trainer 10 on a baseball bat 36 or tennis racquet 38 where a baseball 40 or tennis ball 42 may be hit normally with the trainer 10 attached as shown in fig7 and fig8 . while the principles of the invention have been described herein , it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention . other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein . modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention .
a weight training apparatus which develops strength , suppleness and memory in the muscles used for swinging of a sports implement which may be a baseball bat , tennis racquet , golf club or other sporting implement or equipment . more specifically , the trainer provides for normal use of the sport implement by a user to swing and hit an object such as a golf ball while providing shock absorption to reduce vibration and twisting of the implement upon impact with the object .