fig2 to 4 show a putter in accordance with a primary embodiment of the present invention . as shown in the drawings , the head 10 of the putter according to the present invention has a hollow cylindrical head body having a diameter of 35 mm - 45 mm , preferably 38 mm . in the above head body , a pair of vertical partitions 11a are placed in the front and rear portions inside the head body , thereby forming a central cavity 11 having a volume v 1 . the cavity 11 has either circular or polygonal cross - section . each partition 11a has at least one threaded hole . the above threaded hole of each partition 11a engages with coupling means of a cap 20 , 20a which will be described later herein . the caps 20 and 20a are coupled to the front and rear ends of the head body , respectively . each cap 20 , 20a cooperates with an associated partition 11a in order to form a side cavity having a volume v 2 . as shown in fig2 a handle 12 extends from a given portion of the above head 10 . in the present invention , it is preferable to make the ratio of volume ( v 1 , v 2 ) of the cavities inside the head 10 be v 1 : v 2 = 2 : 1 . however , it should be understood that the volume ratio between the cavities may be changed without affecting the functioning of this invention . in addition , the head 10 may be provided with one or more partitions for forming the cavities . in the above head 10 , both ends of the above cylindrical head body are coupled to the hollow hemispherical caps 20 and 20a . each cap 20 , 20a has the above coupling means engaging with the threaded hole of an associated partition 11a . the above coupling means comprises a rod 21 which axially extends from the center of the inside surface of each cap 20 , 20a . the above rod 21 is at least partially threaded in order to form a screw portion which will be threaded into the threaded hole of the partition 11a . in accordance with the present invention , a plurality of annular weights 26 and 26a may be fitted over the rod 21 of each cap 20 , 20a . each weight 26 , 26a has an inner diameter of larger than the outer diameter of the rod 21 and is used for adjusting the weight of the head 10 . in order to prevent the weights 26 and 26a from suddenly moving on the rods 21 and 21a of the caps 20a and 20a , it is preferable to fit a biasing means or a compression coil spring over each rod 21 , 21a between the inside surface of an associated cap 20 , 20a and the weights 26 and 26a . as shown in fig2 the peak of each hemispherical cap 20 , 20a may be provided with a depression . a transparent tap 24 is fitted in the depression of the above cap 20 , 20a with a label of a putter producer interposed between the tap 24 and depression . in this case , the putter will have an additional effect of showing the putter producer and good appearance . in the present invention , an annular groove having a given depth is preferably formed on the coupling edge of each of the cap 20 , 20a and the body 10 . an o - ring 14 , 14a formed of an appropriate material is fitted over the above annular grooves when the caps 20 and 20a are fitted into both ends of the head 10 . the above o - ring 14 , 14a prevents foreign substances such as moisture , grass and sand from being introduced into the cavity 11 of the head 10 . while putting , a golfer selects one of the putters having different weights in accordance with the putting conditions , such as the putting green conditions , that is , wet green or dry green , golfer &# 39 ; s weight and the weather . while selecting the putters , a golfer selects a putter in accordance with one &# 39 ; s subjective preference . as described above , the putter head 10 of the present invention may be provided with the weights 26 and 26a for adjusting the weight of the putter head 10 as shown in fig2 to 4 . in accordance with the primary embodiment of the invention , each weight has an annular configuration suitable to be fitted over the rod 21 , 21a . however , it should be understood that there exist various polygonal configurations of each weight 26 , 26a which yield the same result as that described for the primary embodiment without affecting the functioning of this invention . each annular weight 26 , 26a has an weight of 5 - 50 g , preferably 15 g . in the present invention , it is preferable to fit 0 - 20 weights 26 and 26a , preferably 10 weights , over each rod 21 , 21a . however , a golfer may freely select the number of the weights 26 and 26a , which will be fitted over the rod 21 , 21a , in accordance with one &# 39 ; s preference . the net weight of the head 10 without having any weight 26 , 26a is 250 - 300 g . in order to install the weights 26 , 26a in the head 10 , the biasing means 27 , 27a is fitted over the rod 21 , 21a of each cap 20 , 20a prior to fitting an appropriate number of weights 26 and 26a over the rod 21 , 21a . after fitting the weights 27 and 27a over the rods 21 and 21a of the caps 20 and 20a , the caps 20 and 20a are tightly fitted into both ends of the head 10 , respectively . of course , the weights 26 and 26a may be exclusively fitted over the rod 21 , 21a of either cap 20 or 20a . the above biasing means 27 and 27a interposed between the inside surfaces of the caps 20 and 20a and the weights 26 and 26a prevent the weights 26 and 26a from moving on the rods 21 and 21 inside the head 10 . in addition , a plurality of o - rings ( not shown ) formed of elastic rubber may be interposed between the weights 26 and 26a in order to prevent noises generated from the weights 26 and 26a while putting . in the present invention , it is preferable to fit the caps 20 and 20a into both ends of the head 10 through screw - type fitting . in order to achieve the above screw - type fitting of the caps 20 and 20a into the head 10 , the fitting edges of the caps 20 and 20a and of the head 10 are preferable provided with threaded portions . of course , the caps 20 and 20a may be fitted into both ends of the head 10 through another method , such as interference fit . in order to make it easy to fit the caps 20 and 20a into both ends of the head 10 , the fitting edge of each cap 20 , 20a is preferably provided with a knurled portion 22 , 22a . the putter head 10 of the present invention is a cylindrical body . with the cylindrical body of the head 10 , the putter head 10 knocks the center of a golf ball regardless of the putting postures of a golfer while putting as shown in fig5 . the putting force of the golfer is thus precisely transmitted to the ball through the putter regardless of the golfer &# 39 ; s putting postures , thereby improving the putting precision of the golfer . as described above , the present invention provides a structurally improved putter . the head of the above putter is a cylindrical body with a cavity . with the cylindrical configuration of the putter head , the putter head knocks the center of a golf ball regardless of the golfer &# 39 ; s putting postures while putting . a plurality of annular weights are provided in the cavity of the head . the number of the weights in the head can be freely changed by a golfer thereby freely adjusting the weight of the head . the above weights are prevented from moving in the cavity by a biasing means . although the preferred embodiments of the present invention have been disclosed for illustrative purposes , those skilled in the art will appreciate that various modifications , additions and substitutions are possible , without departing from the scope and spirit of the invention as disclosed in the accompanying claims .
a structurally improved putter is disclosed . the putter has a cylindrical head suitable to easily knock the central portion of a golf ball regardless of the putting postures of a golfer while putting . the head is provided with an internal cavity suitable to transmit the putting impact and vibrations of the head to the golfer &# 39 ; s hands through the grip without failure . the cavity also allows the golfer to precisely feel both the putting senses and rolling directions of the ball thereby improving the putting precision of the golfer . the above putter head is provided with weights installed in the cavity . the weight of the above putter is easily adjusted by changing the number of weights .