US2737432A

US2737432A - Golf practice apparatus

Info

Publication number: US2737432A
Application number: US309102A
Authority: US
Inventors: Jenks George M Troutman
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-01-28
Filing date: 1952-09-11
Publication date: 1956-03-06
Anticipated expiration: 1973-03-06

Description

March 6, 1956 G. M. T. JENKS 2,737,432

GOLF PRACTICE APPARATUS Original Filed Jan. 28, 1949 9 Sheets-Sheet l FIGZ- ATTORNEYS.

March 6, 1956 G. M. T. JENKS 2,737,432

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March 6, 1956 a. M. T. JENKS GOLF PRACTICE APPARATUS 9 Sheets-Sheet 3 Original Filed Jan. 28, 1949 FIG: 5-

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March 6, 1956 e. M. T. JENKS 2,737,432

GOLF PRACTICE APPARATUS Original Filed Jan. 28, 1949 9 Sheets-Sheet 7 INVENTOR:

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March 6, 1956 G. M. T. JENKS 2,737,432

GOLF PRACTICE APPARATUS Original Filed Jan. 28, 1949 9 Sheets-Sheet 8 1 1 26 L lid ay .Fli 21- BY -16? mi ATTORNEYS.

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United States Patent GOLF PRACTEE APPARATUS George M. Troutman Jenlis, St. Petersburg, Fla.

Original application January 28, 1%9, No. 73,264, new Patent No. 2,626,151, dated January 20, 1%3. Divided and this application September 11, 1952, Serial No. 399,162

Qlaims. (Cl. 346-44) This invention relates to a golf practice apparatus and more particularly concerns a golf practice apparatus adapted to coordinate the movement of diiferent parts of a golfers body during the course of numerous practice swings for ultimate attainment of an ideal golf swing. This application is a division out of my copending parent application Serial Number 73,264, filed January 28, 1949, for Golf Practice Apparatus, now U. S. Patent No. 2,626,151, and is particularly directed to the invention wherein recording means are incorporated into a golf practice apparatus of the type claimed in said parent application.

The broad idea of controlling the movement of a single member of a golfers body during the course of a practice swing has been for several years an accepted method of teaching and perfecting a golf swing. Among others, numerous devices have been proposed to date for restraining a golfers head to prevent him from looking up before the club head has contacted the ball. There are also devices on the market for preventing excessive sliding motion of the hips; while other devices have been devised to hold the right elbow in an elevated position during the swing of the club. Other harnesses and straps for restraining the shoulders have been marketed from time to time, but the foregoing devices do not appear to have met with any great success because they correct the motion of only one part of the body while permitting other parts of the body to repeat old mistakes or even to develop new incorrect motions as a result of the restriction of the corrected member. In order to teach an ideal golf swing by restricting the movements of a golfers body, I have found that it is necessary to treat the entire body as a unit and coordinate the individual motions of the several pertinent parts of a golfers body in such a way that the movement of any single part of the body is dependent upon the movements of other parts. To my knowledge the various devices of the prior art have failed to do this and have consequently failed to accomplish their broad purpose.

It is accordingly an object of this invention to provide a golf practice device which coordinates the individual motions of the principal parts of a golfers body and thereby teaches an ideal golf swing.

A further object is to provide an mechanism for correlating the motions of the golfers hands, wrists, arms, head, shoulders, hips, knees, and feet into one integrated motion.

A still further obiect of this invention is to provide a golf practice apparatus for holding various parts of a golfers body in definitely spaced relationship during successive stages of the golf swing.

A further object is to provide a means for controlling the respective motions of different parts of a golfers body so that the motion of a single body member is actuated by movements of other parts of the body. Another object of this invention is to provide a mechanism adapted to be attached to the body of the golfer that receives an initial force from the hands, arms and shoulders of the golfer and transmits said force to other parts of the golfers body to create an integrated coordinated motion through the entire course of a golf swing.

More particularly it is an object of this invention to provide a machine of the foregoing character wherein an ideal golf swing can be recorded and then reproduced.

Other objects and means for attaining them will appear from the accompanying drawings wherein:

Fig. 1 is a view in side elevation of a golf practice apparatus conveniently embodying the present improvements, with portions thereof broken out to expose important details which would otherwise be hidden, and showing a practice golfer in the act of executing a golf swing.

Fig. 2 is a fragmentary view in longitudinal section of a portion of the mechanism for controlling the arm and wrist movements of the practice golfer.

Fig. 3 is a fragmentary view in top plan looking as indicated by the angled arrows III-Ill in Fig. 2.

Fig. 4 is a fragmentary view in section taken as indicated by the angled arrows lV-lV in Fig. 2.

Fig. 5 is a view partly in elevation and partly in vertical section taken as indicated by the angled arrows VV in Figs. 2 and 1.

6 is a view in longitudinal section of another portion of the arm and wrist motion control mechanism.

Fig. 7 is a fragmentary view in top plan looking as indicated by the angled arrows Vll-VII in Fig. 1.

Fig. 8 is a view in side elevation looking toward the bottom of Fig. 7.

Figs. 9 and 10 are horizontal sectional views taken as indicated respectively by the angled arrows lX-IX and X-X in Fig. 1.

Fig. 11 is a fragmentary view in top plan showing foot plates on which the practiced golfer is adapted to stand. and the parts by which said plates are directly actuated during the execution of a golf swing.

Fig. 12 is a fragmentary view in vertical section taken as indicated by the angled arrows XlL-Xll in Fig. 11.

Fig. 13 is a fragmentary view in longitudinal section of the means provided for controlling the head movements of the golfer incident to swinging the golf club; and

Fig. 14 is a horizontal sectional view taken as indicated by the angled arrows XlV-XiV in Fig. 13.

Figs. 16 and 15 are diagrams showing the circuits for various electrical devices employed in the apparatus.

Fig. 17 is an axial sectional view of a rotary control switch shown in Fig. 16, the section being taken as indicated by the angled arrows XVI-XVI in the latter illustration.

Figs. 18, 19, 20 and 21 are views respectively like Figs. 1, 2, 11 and 12 showing the various mechanisms of the apparatus arranged for producing record graphs or generating templates for use in cutting different cams instrumental in bringing about the desired arm, hand, hip and foot movements necessary to an ideal golf swing.

Fig. 22 is a perspective view of a portion of the linkage illustrated in Figs. 2 and 3.

I have discovered from studying the golf swings of leading golfers both during actual play and from photographs, that although there are individual differences of minor nature in their strokes, there is a substantial similarity in the basic patterns of motion of the different parts of the body and a definite relationship of the timing of these motions with respect to each other. A detailed analysis of the arm motions discloses that the arms travel in substantially a single plane in the swing of most experts and that the hands described a nearly circular are about a center in the neighborhood of the left shoulder. During the swing of the arms, the wrists are cocked and uncooked in definite relationship with the rest of the golf swing. The hips move in a definite relationship to the movements of the hands and wrists and describe a combined rotary and sliding motion. Similarly the feet and knees move in relation with the other members of the bod faith more detailed reference first more particularly to Figs. 1 and 9 of these illustrations, it will be seen that my improved golf practice apparatus comprises a base 1 which serves as a platform and which has divergently arranged

inset foot plates

2 and 3 adjacent one end thereof whereon the golf player is adapted to stand. Rising from the base 1 at the opposite end to the front of the players station is a hollow post 4 with a telescopic extension 5 which is vertically adjustable and securable in adjusted positions by a hand screw 6. Supported by the post 4 is a mechanism 7 by which the arm, hand and wrist movements essential to the execution of an ideal swing of a golf club C grasped in the hands of the player,'are controlled. The mechanism 7 includes an L-shaped bracket 8 which is pivotally adjustable about the axis of a manually operable clamp screw 9 at the top of post i, the upstanding portion of said bracket being hollow and terminating in spherical head 10, see Fig. 2. In preparation for the use of the apparatus, the d stments at 7 and 8 are so made that the axis of an inclined shaft 11 journalled in the head 10, would if extended, pass approximately through the left sholder of the player standing on the platform 1. Slidably mounted on a tubular radial proiection 12 of the head thro gh which the shaft 11 passes, is a cylindric housing 13 whereof the central hub 14 fits slidingly over said projection. The shaft 11. is not only rotatable in the head 10, but axially shiftable as well against the force of a compression spring 15 for a purpose later explained. Through engagement of a fixed collar 16 on the shaft 11 with the outer end of the hub 14 of the housing 13, the housing 13 together with the parts contained therein and the elementsyet to be described connected to them are caused to move axially with said shaft. Anchored in a lug 17 at the top of head 10 is a pin 13 with which an eccentrically disposed boss 19 at the back of housing 13 is slidingly engaged to prevent rotation of the latter as it is axially shifted. To the front end of shaft 11 is afiixed a fork 20 whereof the extremities 41 are pivoted at 21 to the extremities of an oppositely arranged fork 22 at the contiguous end of a tubular shaft 23 extending at an obtuse angle to said shaft 11 toward the players station. Secured to shaft 23, at its distal end, is a hollow arm 24. Rotatable in an angularly disposed bearing 25, which is fixed to the outer end of arm 24, is a sleeve 26, see Fig. 6, through which the handle end of the golf club C is passed and in which said club is removably secured by a clutch collar indicated at 27. Axially within the tubular shaft 23 is an independently rotative shaft 28 composed of telescoping sections from which motion is transmitted, through a pair of

bevel gears

29, 30, to a shaft 31 within the hollow arm 24, and from the latter shaft through another pair of bevel gears 32, 33, to the sleeve 26 in which the golf club C is held to induce the desired wrist movements of the practice golfer. The shaft 28 (Figs. 2 and 3) protrudes from the upper end of tube 23 where, through a universal joint 34 it is coupled with a short shaft 35 which is rotative in a bearing 36 on a carriage 37 disposed within the frontal upper part of the housing 13. As shown, the carriage 37 has outward arms 38 pivoted at the top which, through similarly pivoted links 39, are pivotally coupled with arms 40 upstanding from the extremities 41 of the fork 20. The carriage 37 also has pendent arms 42 pivotally connected to arms 43 independently of shaft 11 and hub 14 and extending from the yoke 22 beyond the pivots 21. The pivotally connected

arms

39, 4d, 42, 43 constitute a pair of spacedapart, collapsible, parallelogram linkages. Afiixed to the inner end of shaft 35 is a spur pinion 45 that meshes with a spur gear 46 on a parallel shaft 47 rotatably supported in another bearing on the carriage 37. The gear'46 is axially slidable on the shaft 47 and has an eccentrically disposed axis stud 29 for a roller 59 arranged to ride within the differently shaped inner peripheries of ring earns 51 and 52 each fixed in the rear of the housing 13. Pivoted at 55 on the bearing 36 of carriage 37 is an arm 56 with roller 57 which is adapted to concurrently travel within the differently shaped 58, 59 secured in juxtaposed relation within the housing 13 at the front. As shown r ller arm 56 has a lateral hook projection engaging a circumferential groove in the hub of the gear 46 whereby said gear will be shifted longitudinally on the shaft 47 as said arm 56 moves about its pivot 55. The means for shifting the roller arm 56 comprises a push-pull solenoid 61 whereof the armature 62 bears against one side of said arm. The spring shown at 63 serves to normally maintain the roller 56 in the position in which it is sh wn in Fig. 2, while springs 64 in tension between the arms 44 of fork and a collar 6411 free on shaft 28, urge collar 64a against the upper end of tube 23 and accordingly urge the carriage 37 upwardly within the housing 13, and roller 57 against cams 53, 59.

Affixed to the end of shaft 11 protruding from the back of the head 19 is an arm 65 whereto is pivotally connected a smaller arm at: with a roller 67 thereon arranged to be shifted at difierent times during the execution of a goif swing as later on explained, from one to the other of two concentric cam rings 68, 69 rigidly secured to said head. For the purpose of shifting the roller 57 between these cams 53, 69 there is provided a puli solenoid '73 on arm 65 whereof the armature 71 is coupled with lever projection '72 on the arm 66. Cam rings 63, 69 have specifically shaped surfaces contacting roller e7, serving to move roller 67 oodily toward and away from the lug 17, thus causing controlled axial movement of shaft 11, during the course of the golf swing.

The foot plates 2 and 3 (Figs. 1, 9 and 10) are disposed within openings in the top of platform 1, and connected to said platform by hinges 81? for capacity to rock independently up and down within said openings. The means for actuating the

foot plates

2 and 3 includes a pair of rotary cams S1 and 82 afiixed side by side on a horizontal shaft 83 beneath the platform 1. As shown in Figs. 11 and 12 the cams 81 and 82 are engaged by rollers 84, 85 on bell cranks 86, 87 which are rockably supported by fixed bearings and connected by

links

88 and 89 to the

respective foot plates

2 and 3. The spring indicated at 86a acts upon the bell cranks 86, 87 to keep the rollers 84, 85 in engagement with cams 81, 82.

The means relied upon to induce the desired back hip, and knee movements during the club swing includes a belt 90 which is attached about the waist of the player. At opposite sides and at the back, the belt 90 has pivotal connections with the upper ends of upright link rods 91, 92 and 93. As shown in Fig. 9, the rods 91, 92 extend down through arcuate clearance slots 95 in the top of platform 1, and at their lower ends are connected to the tops of

upright arms

96, 97, medially pivoted on the outer ends of

horizontal arms

100, 191, fulcrumed for independent up and down movement, to a fixed collar 102 on a vertical shaft 103 which extends down through the platform 1 in the axis center of the arcuate slots 95. Rollers 105, 106 at the outer ends of

arms

100, 101 run on the bottom edge of an arcuate cam 107 afiixed to platform 1 in concentric relation to shaft 103, while rollers 108, 109 at the lower ends of the

arms

96, 97 run against the outer circumferential face of an arcuate earn 110. The bottom end of rod 93 is similarly connected to the upper end of a vertical arm 111 which is rockably supported at the end of a third radial arm 112 capable of up and down movement about a pivotal connection with a collar 113, on vertical shaft 103 above the platform 1. Likewise as shown, the arm 111 is provided with a roller 114 to run against the outer circumferential face of an arcuate cam on the platform 1, and the radial arm 112 with a roller 116 to run on the top edge of arcuate cam 117 above platform 1.

Springs

118, 119 and 120 influential upon the arms 96, and 111 serve to hold the rollers 105, 106 and 114 to the cams 107 and 115, respectively.

Rotary motion is imparted to vertical shaft 103, through

gears

120a, 121, from the horizontal shaft 83 which is arranged to be actuated in turn through bevel gears 122, 123 by a Vickers hydraulic transmission unit 125 (Figs. 1, 7 and 8) located together with an electric motor 126, beneath the platform 1. Associated with the motor 126 is a speed reducer 127 to one end of the output shaft 128 of which is secured a cam disk 129. This cam disk 129 is engaged by a roller 13%) on a rocker arm 131 connected by a link rod 132 to the lever 133 of the control 135 on the transmission unit 125. Alongside the unit 125 and operatively connected thereto by a belt 136, is a second hydraulic transmission unit 137 with a control 138 Whereof the actuating arm 139 is coupled, through a link rod 140, with a rocker arm 141 having a roller 142 bearing upon the periphery of a rotary cam 14-3 at the other end of the shaft 128 of speed reducer 127. By means of bevel gears 145, 14% the unit 137 is connected to one end of another horizontal shaft 147, the distal end of which is in turn connected by bevel gears, 1 18, 149 (Fig. l) to a short vertical shaft 15% rotatively supported in a suitable bearing on top of platform immediately forward of the post 4. Through a universal joint 151, shaft 151? is connected to the lower end of extensible link 15?. whereof the component sections are telescopically interengaged, and whereof the upper section 153 is connected by universal joint 155 to the bottom end of a shaft 155 (Fig. 2) rotatably supported in the hollow upright portion of angular bracket 9. A bevel gear 155 (Fig. 2) at the top end of shaft 155a meshes with a bevel gear 157 splined to shaft 11 within the spherical head 1d. As a consequence of the interposed connections just described, it will be seen that the back, hip, knee and ankle movements of the golfer are all controlled by the mechanism of Pig. 7 in properly timed relation with the arm and hand movements during the execution of a golf swing.

The means provided for controlling the head movements of the practice golfer as he swings the club C, includes a cap 160, see figs. l, 13 and 14. This cap is secured by a jaw strap 1%, and extending over the top thereof from opposite sides of a crown band is an arch piece 163 with a central upstanding stud 165. As shown, the stud 165 has an enlargement at its upward end which fits, with capacity for rotation, into a fixed spherical socket -nernber 167 at the end of a tubular support 168, Independently pivoted on the enlargement res of stud 165 are arcuate shoes which are normally maintained in frictional engagement with the inner surface of the socket 167 by springs 1'73 to prevent rotation of the cap 1% and hence of the golfers head until after the ball is contacted by the club C as later on explained, and which are arranged to be withdrawn upon energization of an electrical magnet 171 fixed upon said enlargement. The support 163 is in the form of a diametrically reduced flexible prolongation of the upper vertically adjustable section 172 of a tubular post immediately to the rear of the golfers station on the platform 1. The prolongation 17.2 is fixable in adjusted positions by the clamp screw indicated at 175.

As diagrammatically shown in 15, current flow to the coils of the roller arm shifting solenoids er and is controlled by a switch 176, which, see Figs. 2 and 4, is mounted on the back of head 10 with its actuating lever 177 in the path of a stud 17% extending outward through an arcuate slot 179 from a disk within said head. The disk 180 is free on a spacing sleeve surrounding the shaft 11 Within the head 1% and frictionally engaged by the flanged end of a slide sleeve 182; which fits over the hub of bevel gear 157. The sleeve is subject to the action of a compression spring 183 and obliged to rotate with gear 157 through engagement of diametral slots therein with pin projections 135 on the gear hub. This arrangement is such that the stud 178 is moved away from the switch lever 177 during the drive swing of the golf club, and moved toward said lever to operate the switch 176 for simultaneous closing of the circuit through the solenoids 51 and 7h.

The coil of the magnet 171 of the brake means for the cap 16% is connected in a current supply circuit 1?; 133 (Fig. 16) with a rotary switch 190. Projecting from the shaft 191 of this switch are three equally spaced spring contact arms 12 2, 192a and 192D adapted to be successively moved into engagement with the fixed contact at 193; and secured to said shaft is a ratchet wheel 1% with six teeth adapted to be picked one at a time by a pawl 195. Freely oscillatable about the shaft 191 is a spring pulled arm 1% which carries the pawl 195, and which, through a rod 397, is coupled to the armature 198 of a pull solenoid interposed in a current supply line 280, 291. Current flow through the coil of solenoid 191 is controlled by a rotary switch 2 32 which, see Figs. 1 and 1'7, is supported by an upwardly reaching arm 2tl3 on bracket 1) that carries the mechanism 7. The diametrically reduced rear end of shaft extends axially through the casing 204- of switch and splined to it is a disk 2115 which is confined to rotation in said casing, see Fig. 17. Projecting from the disk is an eccentrically disposed stud 2 36 which is yicldingly engaged by the radial arm 267a of a coiled contact spring 207 aflixed to an axial bearing boss 203 of casing 284. The contact stud at 2&9 projects from a holder piece 215 of insulation secured to the switch casing 2% with capacity for adjustment circuinferentially thereabout, and extends into the path of the radial of contact spring 2 37. The terminals of current supply line in which he solenoid coil 1% is interposed are connected respectively to the shaft and the contact By closing of a push button switch 211 in a branch circuit 213 it is possible to operate the solenoid 1% for a purpose also later explained. Likewise, the ratc et wheel and the parts associated therewith may be placed in any convenient location, for example, an arm (Fig. l) which supports the switch The wiring from the switch 2G2 to the magnet 171 for holding the cap against rotation is in practice run beneath the platforn 1 and threaded up through the hollow post 173 and its hollow prolongations 172 and Operation Let it be assumed that the player has taken his position on the platform with his feet engaged in the straps 2a and have 3a of the

foot plates

2 and 3, that posts 4 and 173 been adjusted to set the rnech head, and that the *eit all as shown in Fi cured about his waist,

i so now facing forhc pushes the button is energ zed and 211 with the result the ratchet wheel rflCkECl oy one tooth to move the arm on 191 to the broken line position in Fig. 1 t

6 oil the contact The circuit 137, 183 is thereby opened, magnet 171 de-cnergized, and the rake shoes 169 (Fig. 14) released to the action of the springs 17% to temper illy p= t, e player from moving his head. The motor is llv started in readiness for the player to execute a s; .g with the club C grasped in his hands. Duri g the swing, the players (which move roller 57 toward and away from shaft 11 during the swing), with corresponding changein the relarionship of the parts constituting the parallelogram 37,

39, 40 and 43 by which the shaft 23 and the club holder are sustained from the mechanism 7. The movement of the golfers hands relative to his own body is governed through concurrent axial shifting of shaft 11 by action of

cams

68, 69 upon roller 67. The golfers hands are thus adjusted in position toward and away from his body during the course of the swing. Also at the same time, a twisting movement is concurrently imparted to the players wrists by rotation of the shaft 28 inside tubular shaft 23. This motion is transmitted to the shaft 28 from shaft 35 (Fig. 2) by the gears 45, 46 as the roller i travels in the groove of cam 51, and from said shaft 28 to the club holder sleeve 27 (Fig. 6) through the shaft 31. and bevel gears 29, 3t), 32 and 33. At the moment of contact of the club with the ball, the various parts of the control mechanism occupy the positions in which they are shown in Figs. 3 and 5.

At about the time that the ball is struck with the club C, the spring contact 297a (Fig. 16) encounters the fixed contact 299 to close the

circuit

220, 201 through the solenoid 199 which is thereby energized and the ratchet wheel 194 racked another tooth to move the arm 122a into engagement with fixed contact 193. The

circuit

177, 178, is accordingly closed and the magnet 171 energized to withdraw the brake shoes 169 so that the player may now move his head to follow the flight of the ball as he completes the drive swing. Upon initiation of the reverse or back swing, the stud 178 (Figs. 2 and 4) moves into engagement with the arm 177 of switch 176 to close the circuit (Fig. through the

solenoids

61 and 70 which will thereby be energized to cause shifting of the rollers 5t and 57 from the

cams

51 and 58 to the

cams

52 and 59 as shown in broken lines in Fig. 2, and shifting of the roller 67 at the same time from cam 68 to cam 69. Thus during the back swing, the roller 57 will be acted upon by the cam 59, the roller 50 by cam 52, and the roller 67 by cam 69. Accordingly, the movements then imparted to the arms, hands and wrists of the golfer will be different from those imparted during the drive swing as prescribed by the different shaping of

cams

52, 59 and 69. As the shaft 11 (Fig. 2) turns as above explained, motion is transmitted by the gears 15:5, 157 to vertical shaft 155 and from the latter, through bevel gears 14-3, 149 (Fig. 1) to shaft 14-7, which through bevel gears 145 and 146, is coupled with transmission unit 137 (Fig. 7) driven together with transmission unit 125 by electric motor 125. The cams 129 and 143 the shaft of speed reducer 137 associated with motor 126 so govern the operation of the units 137 and 1125 that the shaft 83, connected to the latter unit by the bevel gears 122 and 123, is turned at the proper speeds and in the proper directions for communication to the vertical shaft 103, through bevel gears 12%, 121, of the required motions for actuation of the means by which the players hip, back and ankle movements are forced. Thus in practice with my improved apparatus, all of the body movements of the golfer are coordinated in timed relation, so that by persistence, he will ultimately acquire an ideal swing. By employing the

relay power devices

125, 125, 137 in the way described, no restraint is imposed upon the player to interfere with the ready and easy swing of the club.

In initially settiir up the apparatus, it is theoretically possible to make geometric calculations based upon detailed analysis of photographs of an expert golfers swing and so arrive at adequate curves for the various cams embodied in tr e inter-connected mechanisms of the apparatus. However, the results obtained by this method are at best only approximate, and I accordingly prefer to determine the shape of the several cams experimentally by having a golf expert. preferably one noted as a golf stylist, swing the club C in the apparatus. To prepare the apparatus for this purpose, the solenoid 61 is removed from the link 3%, and the arm 66 with its roller 67 removed from the arm 65 at the rear end of shaft 11. After removal of these parts, a relatively stifi disk .8 220 (Fig. 18) with a paper chart facing 221 is placed, with interposition of a resilient cushioning gasket 222, into the back of housing 13. An annular retaining element 223 is thereupon inserted into the housing 13 and temporarily secured by screws 224, and another chart sheet 225 applied to the recessed frontal face of said element. Another annular retaining element 226 is next temporarily secured by screws 227 to the back of the head 10 and a chart band 223 applied to the interior thereof. For marking the chart sheet 221, a stylus 239 with a backing spring 231 is inserted into the axial bore of the stud 49 by which the roller 50 is ordinarily supported on gear 45. For marking the chart sheet 225, a second stylus 232 with a backing spring 233 is provided, the same being inserted into the socket of a holder 23-: temporarily secured to the carriage 37, so that the axis thereof corresponds in position to the axis of the roller 57 which it replaces. For marking the chart band 228, a third spring pressed stylus 235' is used in a projection 236 detachably secured temporarily to arm 65 by a screw 237, the point of said stylus being positioned to correspond with the tangent point of the roller 67 which it replaces. With this preparation, an expert player is called upon to execute several swings during each of which the

stylii

236, 232, and 235 trace several diiferent curves on the

respective charts

221, 225, and 228 respectively during drive and back swings of the club. A geometrically mean path is taken in each instance which will give the optimum shape for the corresponding cam necessary to the execution of an ideal swing by the practice player. The mean curves thus obtained may be kept for record purposes or used as guides or templates in cutting the cams.

Graphs of the hip and foot movements of a golf player are obtained in a generally similar way as shown in Figs. 19, 20 and 21, by the following procedure: The segmental cams 197, 110, 115 and 117 (Fig. l) are removed and respectively replaced by segmental supports 240, 241, 242 and 243, for marking sheets 244, 245, 246 and 247. The

cam rollers

106, 108, 114 and 116 are also removed and replaced respectively by stylii 248, 249, 259 and 251 to mark the respective sheets. The rotary cams 81 and 32 (Figs. ll and 12), are in turn removed from the shaft 83 and replaced by plain disks 252, 253 (Figs. 20 and 21) for the support of marking sheets 254, 255, and the rollers 84 and 85 replaced by stylii 256 and 257 respectively. With the apparatus as now prepared, the golf player executes a free club swing incident to which the attendant hip and foot movements are transmitted through the rods 92, 93 and foot plates and intermediate parts to the

several arms

96, 101, 111, 112, and recorded by the stylii 248251 and 256, 257 upon the marking sheets or charts 244- 247 and 254, 255 in a manner which will be readily understood.

An advantage attained in the use of the particular mechanisms described herein is that the cams that control the exact courses of movement are removable and replaceable. This means that the golf swing to be taught to a small person need not be the same as the one studied by a tall player, since changes of the cams can be made in a reasonably short time. The replaceability feature has the additional advantage that the swings of expert golf players having widely varied physical statutes can be permanently recorded and reproduced.

The remarkable adaptability of the machine is further demonstrated by the ease with which it can be connected to accommodate a left-handed golfer. An appropriate left-handed golf club is inserted in the holder clamp 27 and the various cams of desired shape are inserted in their respective places and the golf practice device is ready for use. Moreover, reverse cams may be made using curves developed by right handed experts thereby affording an opportunity for left-handed golfers to achieve the usual accuracy attributed to several right-handed golf experts.

Upon reflection it will be apparent that the apparatus I have shown in the drawings and described in the specification herein is only a highly perfected embodiment of my basic invention and numerous other mechanical means for coordinating the motion of respective parts of a golfers body during his swing will readily occur to persons familiar with the mechanical arts upon reading this disclosure. Accordingly I do not limit my claims to the precise details of the mechanisms illustrated in the drawings but intend them to cover my invention in its entirety.

Having thus described my invention, I claim:

1. In a golf practice apparatus, a club holder, a support therefor, driven means attached to said club holder, a first marker and a marking surface operatively associated therewith to record changes of position of said driven means in one direction, a second marker and a marking surface operatively associated therewith to record changes of position of said driven means in another direction, substantially at right angles to the first mentioned direction, a club turning member connected to said club holder and supported by said driven means, and a third marker and a marking surface operatively associated therewith to record graphically the manner in which the club is turned about the axis of its shaft in the course of a golf swing.

2. Golf practice apparatus for recording the arc of a golf players swing comprising a club holder, a support therefor, first recording means, first connecting means attached to said recording means and attached to said club holder to transmit to said first recording means a designation of the path of said club holder toward and away from the center of said arc, second recording means, and second connecting means mounted in definite predetermined fixed position relative to said club holder, said second connecting and recording means having capacity to record the movement of said club holder toward and away from the golfers body in predetermined relation to its movement toward and away from the center of the arc during the course of said swing.

3. Golf practice apparatus comprising a support, a rock shaft axially slidable on said support, first recording means for recording the sliding movement of said rock shaft axially in timed relation to its rocking movement, a club holder arm pivotally supported on a pivot transverse to the axis of said rock shaft, second recording means for recording the swinging movement of said club holder arm about said pivot also in timed relation to the rocking movement of said rock shaft, in definite predetermined relation to the recording of said axial movement, and means for attaching a golf club to said club holder arm to enable a golfer to swing said club freely and record the characteristics of his swing.

4. Golf practice apparatus comprising a support, a rock shaft axially slidable on said support, first recording means for recording the sliding movement of said rock shaft axially in timed relation to its rocking movement, a hollow club holder arm pivotally supported on a pivot transverse to the axis of said rock shaft, second recording means for recording the swinging movement of said club holder arm about said pivot also in timed relation to the rocking movement of said rock shaft, an independently rotative shaft disposed within said hollow shaft, third recording means for recording the rotary movement of said independently rotative shaft also in timed relation to the rocking movement of said rock shaft, means for attaching a golf club to said club holder arm, and connecting means for transmitting the rotary movement of said golf club about its axis to said independently rotative shaft.

5. A golf practice apparatus comprising a club holder, a support therefor, first recording means including a marking instrument and marked sheet between said holder and support for recording the movements of the hands and arms of a golf player, and a hip movement recording de vice connected to said first recording means and timed with the motion of the first recording means, and adapted to record the movement of the golf players hips in three dimensions in interdependent relation with the recording of the movements of the golf players hands and arms.

References Cited in the file of this patent UNITED STATES PATENTS 1,722,069 Widney July 23, 1929 2,223,849 Fogler et a1. Dec. 3, 1940 2,328,408 Bell et a1. Aug. 31, 1943 2,458,932 Cottingham Jan. 11, 1949 FOREIGN PATENTS 397,549 Germany June 26, 1924