SWING TRAINING DEVICE
TECHNICAL FIELD
This invention relates to training devices which have as their purpose, assisting in the development of a correct swing in games, such as golf, where a ball is struck by a club, bat, racquet or the like. Although principally developed in connection with golf, the present invention has application to other sports such as baseball and tennis. For the sake of simplicity the invention will be described herein principally in its application to training of the golf swing.
BACKGROUND ART
Golf swing training devices have been widely proposed in the prior art, in which a club or a shaft representing a club, is constrained in some manner as to the path in which it may be swung by the user.
An early example of such apparatus is that of Kirkham British patent 174,140, in which a golf-club shaft is connected by means of a universal joint to a carriage which runs on a guide rail, the latter being shaped to define the desired path of the club head.
In MacNaughton et al U.S. patent 1,567,530 there is described a somewhat similar device, in which the club shaft is constrained in its path by attachment to a guide mounted on a rail, in this case the shaft being attached by means of a ring mounted on the guide so as to be capable of swivelling movement.
The prior art includes examples of similar swing training devices in which the guide rail or rails, and the travelling guide, are modified in various, often complex, ways, to force desired movement of the club head, either in its trajectory and plane, or in its rotation as well.
Few of the known prior art proposals have succeeded in providing significant benefits in golf training, and it is believed that this is due to the fact that in general, the emphasis in their design has been on the constraint of the trajectory of the club head, rather than on
the correct movement of the golfer's hands, which must ultimately control the club when it is swung without the constraint of the training device. The present invention proceeds from a recognition of this requirement.
DISCLOSURE OF THE INVENTION The present invention basically resides in a swing training device comprising a swing path guide ring which is adjustable both as to the inclination of its plane and as to its overall height, with a club shaft guide which travels on the swing path guide, a club shaft being connected with the shaft guide in such a way as to allow rotation of the shaft about its axis, axial movement of the shaft relative to the shaft guide, and pivoting movement of the shaft relative to the shaft guide within the swing plane. The shaft guide may also rotate about the swing path guide axis at any point thereon.
In this way, when used under skilled instruction, the device of the present invention facilitates the development of a correct swing by encouraging correct movement and timing of the hands and arms and through this, of the user's basic swing characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevation of a golf swing training device embodying the present invention; Figure 2 is a side elevation of the device illustrated in
Fig. 1;
Figure 3 is a front elevation of the roller guide assembly employed in the device;
Figure 4 is a side elevation of the roller guide of Fig. 3; Figure 5 is a plan view of the roller guide assembly of
Figs. 3 and 4;
Figure 6 shows in side elevation, the construction and mounting of a front leg of the device;
Figure 7 illustrates the base plate of the device;
Figures 8 and 9 illustrate the shape of the device, in side elevation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in Figs. 1 and 2, the golf swing training apparatus comprises an open ring 20, preferably of steel tube, the ends of which are connected, at the top of the device, by a joining member 21, also preferably of steel. The left hand portion 22 of the ring 20 as viewed in Fig. 1 is shaped to approximate the backswing and downswing trajectory of a golfer's hands, while the right hand portion 23 is shaped to approximate the follow-through trajectory. (It will be appreciated that the illustrated device is constructed for golfers with a right-handed swing. The ring shape described herein would be reversed for a left-hander.) As a golfer's hands rise to a greater height on the follow-through than on the backswing, the height of the ring is greater at the end of the follow-through portion 23 than at the end of the backswing portion 22.
The ring 20 is supported by means of three legs, a rear leg consisting of telescoping portions 24 and 25, and two front legs consisting of telescoping portions 26 and 27. The rear leg portion 25 is designed to rest on the floor or other surface on which the device is stood for use, and for this purpose may be provided with a foot 28 of rubber or plastics material, while each front leg portion is adapted, by means of a hinged plate 29, for fixing to a base plate 30 to be described in more detail below. Each plate 29 is attached to the foot of its respective leg portion 27 by means of a hinge pivot 31 and a plate 32.
At the upper end of each leg portion 25 and 27, in which the upper leg portions 24 and 26 slide for adjustment of the height and inclination of the ring 20, there is provided a fixing screw 58, by which the portions 24 and 25, and 26 and 27, may be locked in their desired position. The upper leg portions 24 and 26 are provided with numbered graduations 33 to enable the user to set each leg to a predetermined extension.
O PI _
The upper end of each leg portion 26 is attached to the ring 20 by means of an off-set tubular portion 34 attached to the ring by a bolt and nut 35. This off-set portion 34 enables the club shaft guide, described below, to pass the front legs without obstruction.
Mounted on the ring 20 is a club shaft guide 35, the construction of which, in this exemplary embodiment, is illustrated in detail in Figs. 3, 4 and 5. The purpose of this guide is to constrain the movement of the club shaft 36 to the correct swing path, while enabling the user to develop correct movement of the hands, wrists, arms and body throughout the swing with the aid of the guide ring 20.
In the illustrated embodiment, the club employed is a conventional golf club, with a head 37 on the shaft 36. A normal golf club need not, however, be employed, as there is no addressing of a ball in the use of the device of this invention, where the concern is with the training of correct hand movement. Some form of head must be provided on the shaft to give the correct swing weight, and this head should be shaped in a manner which enables the user to check that the cl-ub face is correctly orientated throughout the swing. The guide 35 consists of a back plate 38 which may be of plastics or metal, on which is mounted four rollers, preferably of nylon or similar material. The lower rollers 39 are mounted on axles 40 fixed to the plate 38, and retained on those axles by means of washers 41 and circlips 42, while the upper rollers 43 are mounted on axles 44 which are fixed to the plate 38 in clearance holes 45 by means of transverse pins 46 which allow the axles 44 to pivot to a l mited degree towards and away from the rollers 39, under the action of a member 47 formed of spring steel, which biases the rollers 43 towards the rollers 39, so that the opposed roller pairs will maintain contact with the ring 20 throughout the movement of the guide 35 on the ring 20. The spring member 47 is fixed to the back plate by screw 48, and engages in slots (not shown) in the outer ends of the axles 44, biasing these ends towards the rollers 39 and also retaining the rollers 43 on the axles 44 by spacers 49.
Mounted on a pin 50 which is free to rotate relative to the back plate
38 is a member 51 which is provided with a passage 52 in which the club shaft 36 is received with a free sliding fit. In this way, the club shaft 36, while attached to the guide 35, is free to rotate and to move axially relative to the guide.
The base 30 is provided for the combined purpose of stabilising the training device against movement under the forces generated by the user, and for guiding the user as to the correct placement of his feet under instruction from the golfing professional. The hinge plates 29 are attached to the base 30 by bolts and wing nuts 52, and for convenience of packaging the base is made in two sections joined by hinges 53.
Although shown here as being of rigid material, in an advantageous embodiment the base is constructed in a resilient material, preferably plastics, and its surface is formed in a manner which will enable the user comfortably to wear conventional spiked golf shoes. In such a case the base may be formed in more sections, maintained in position by fixing to a frame to which the leg portions 27 are attached.
Over the major part of the upper surface of the base 30 there is provided a co-ordinate grid 54 by means of which the positioning of the left and right feet can be identified by the respectively numerically and alphabetically designated grid lines.
Under the guidance of his instructor, the user will set the height of the ring by adjusting the front legs to the correct length for his height and arm length, and will set the inclination of the swing plane for the iron or wood of a particular loft by adjusting the length of the rear leg. The user will then check his foot positioning against the grid 54, and operate the device by carrying out repeated cycles of the golf swing. To the extent, if any, that the club shaft 20 reaches the extremity of the ring on the backswing or follow-through, cushioning of the impact is provided by sleeves 55 of rubber or other resilient material .
Correct movement of the hands and timing of the swing will be aided by the device, without actual restraint being imposed upon the arc or plane of the hands or club-head. The user will learn by the feel of his swing when his hands, and therefore the club, are moving in the correct path and plane, and correct timing of the user's arms and hands will be revealed by the ease with which the roller guide 35 travels in this condition.
The contour of the ring 20 in front elevation is shaped approximately to the correct arc of the hands, rather than that of the club head as in most prior art devices. If desired, a resilient device such as a helical compression spring 56 may be provided on the shaft 36 between the roller guide 35 and the club head 37, so that any tendency towards excessive drop of the hands on the downswing, or "snatching" on the follow-through, will be revealed by this spring coming into contact with the ring 20.
Where it is necessary, the relative height of the guide rail 20 at the top of the backswing and the top of the follow-through may be varied by altering the relative length of the front legs.
The ring 20 is preferably shaped in side elevation to conform to the somewhat non-planar path which has been found by high-speed photography to be characteristic of expert golfers. To this end, the back- and down-swing portion 22 is dished rearwardly out of planarity in a contour substantially as illustrated in Fig. 8, and the follow-through portion 23 is shifted somewhat forwardly as shown in Fig. 9, the broken line 57 representing in each case the reference plane.
For convenience of packaging for sale and transport, the ring 20 may be formed in 4 sections, joined by telescoping portions with inter- engaging formations to ensure that the sections are locked in their correct rotational alignment.