Golf swing training aid

A golf swing training aid (10), to be fitted between a player's knees, has an elongate, telescopic body (11), with foam pads (16, 18) on respetive cross-heads (17, 19) at each end of the body (11). A flexible strap (20) releasably secures one cross-head (17) to one of the player's knees and the other cross-head (17) rests against the other knee. The knees are held stable on the backswing and first half of the downswing of the club, but the aid (10) releases the knees as the swing is completed.

BACKGROUND OF THE INVENTION
 (1) Field of the Invention
 THIS INVENTION relates to a golf swing training aid.
 The invention is particularly suitable for, but not limited to, a swing
 training aid for sports such as golf, baseball, softball, tennis and the
 like.
 Throughout the specification, the term "golf" shall be used to include the
 other sports hereinbefore described.
 (2) Prior Art
 Most golf training aids, designed to aid or improve a player's swing, are
 directed to the movement of the upper body and/or the arms. However,
 little attention has been given to the stability of the lower body during
 the different phases of the swing.
 Ideally, the lower body (ie., hips down) will remain substantially immobile
 during the back swing and on the forward swing until the club/bat moves
 to, or past, the centre line of the body.
 It has been known to use a bucket tied between the knees as an aid to
 stabilise the lower body.
 However, such an arrangement holds the knees apart during the final phase
 of the forward portion of the swing and results in an unnatural swing.
 Examples which have been proposed to control the movement of the player's
 legs during the swing are disclosed in GB 2,284,556 (BUCKINGHAM); U.S.
 Pat. Nos. 5,016,885 (QUIGLEY); 4,706,957 (JACKSON) and 4,088,326
 (BIFULCO).
 The latter three documents disclose aids where the player's knees (or lower
 legs) are bound together at a fixed spacing. In GB 2,284,556 (BUCKINGHAM),
 the golf training device is fitted between both knees below the knee
 joints, with side supports, secured by releasable straps, where a plastic
 swivel bar with a centre pivot interconnects the side supports and allows
 some controlled movement between the legs. While some movement between the
 knees can occur during the swing, both knees must be fastened to the
 device, generating an unnatural movement.
 SUMMARY OF THE PRESENT INVENTION
 It is an object of the present invention to provide a training aid which
 holds the knees substantially stabilised for approximately the first half
 of the swing, while allowing the knees to move as the swing is completed.
 It is a preferred object of the present invention to provide such an aid
 where the knees will be released when the arms are approximately aligned
 with the centre line of the body.
 It is a further preferred object of the present invention to provide such a
 training aid which can be releasably secured at, or adjacent, one of the
 player's knees, and be releasably engageable with the other of his/her
 knees.
 It is a still further preferred object of the present invention to provide
 such an aid which can accommodate a range of spacings between the player's
 knees, eg., to accommodate players of different height and/or stances.
 Other preferred objects of the present invention will become apparent from
 the following description.
 In a broad aspect, the present invention resides in a swing training aid
 for golf or other sports, including:
 an elongate body having respective first and second end portions engageable
 with a player's legs at, or adjacent, the player's knees; and
 a releasable securement means at or adjacent one of the end portions to
 releasably secure the body to the adjacent one of the player's legs; so
 arranged that:
 on a back swing and during at least a portion of a forward swing, the
 player's knees are maintained in a substantially fixed or stable
 relationship, the other end of the body being releasable from the player's
 legs to allow the player's knees to move during the completion of the
 forward swing.
 Preferably, the body is variable in length and may have components which
 are telescopically interconnected. A releasable lock, clip, bolt, pawl or
 like means may be provided to enable the length of the body to be
 selectively set.
 In one preferred embodiment, a pair of box-like members are telescopically
 inter-engaged; while in the second preferred embodiment, a pair of
 knee-engagement cups or yoke-like members are provided at the ends of a
 pair of telescopically inter-engaged tubes.
 Preferably, the securement means is a strap, rope, thong or the like
 releasably securable about one of the player's legs.
 Preferably, the adjacent end portion has a pad or tapered nose which
 provides a pivotal axis for the body when the other end is released from
 the player's other leg.
 Preferably, the other end portion has an inclined face, preferably curved
 in plan view, so arranged that during the completion portion of the swing,
 the player's adjacent knee will tend to force that end portion of the body
 downwardly to release the aid from that knee.
 Preferably, the body will be released from the player's other knee, when
 the arms, on the forward swing, are just in advance or pass, the centre of
 gravity of the aid, ie., approximately in alignment with the centre line
 of the player's body.
 Preferably, for a right-handed golfer or batter, the aid will be secured to
 the left leg at, or above, the left knee, and the aid will releasably
 engage at or above the right knee of the player's right leg. For
 left-handed players, the arrangement will be reversed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring to FIG. 1, the training aid 10 has an elongate body 11 (eg.,
 moulded from suitable plastics material) having a first body leg 12
 telescopically, not rotatably, engaged within the second body leg 13. A
 locking pin 14 is releasably engageable in aligned holes 15, (not shown)
 in the body legs 12, 13 to enable the length of the body 11 to be
 selectively adjustable.
 A resilient (eg., plastic foam) pad 16 is provided on the outer face of a
 cross-head 17 on the first leg 12 and, as shown in FIG. 2, is adapted to
 engage a (right-handed) golfer's left knee just above the knee joint. The
 pad 16 (and cross-head 17) are of shallow concave shape in top plan view.
 A second pad 18, of similar material, is provided on the outer face of a
 cross-head 19 on the second leg 13. This pad 18 is arranged to releasably
 engage the (right-handed) golfer's right knee, just above the knee joint,
 as in FIG. 2. It will be noted that while the pad 18 is also of shallow
 concave profile in top plan view, it is inclined at an angle (eg., in the
 range of 10.degree. to 30.degree.) from the normal to the longitudinal
 axis of the elongate body 11. The pad 18 may incorporate a shallow convex
 profile in end view, as shown in FIG. 1.
 The aid 10 is releasably secured to the player's leg by an elongate strap
 20 which may be wrapped around the player's leg and be secured by a
 releasable fastener 21 incorporating the respective hooks and loop
 portions 21a, 21b of "VELCRO" (Registered Trade Mark) material.
 The strap 20 passes through a loop 22 at one end of an attachment strap 23,
 which is attached to a post 24 on the second leg 13 by a releasable buckle
 25.
 In alternative embodiments, not shown, the strap 20 may be secured about
 the player's leg by clips, buckles or other suitable releasable fasteners.
 In an alternative embodiment not illustrated, the training aid has a
 box-like body (eg., moulded from suitable plastics material) having a
 first body component telescopically received within the second body
 component. A locking pin is receivably engaged in aligned pairs of holes
 in the body components to enable the length of the body to be selectively
 adjustable.
 The "nose" at the distal end of the first body component is tapered in side
 view and substantially concave in plan view to releasably engage the left
 leg of the (right-handed) player at, or just above, the player's left
 knee. A strap assembly has a loop member releasably securable about the
 player's left leg. The loop member may be secured by clips, buckles,
 "Velcro" (Registered Trade Mark) material or like releasable fastening
 means to enable the training aid to be releasably secured to the player's
 leg.
 The "tail" at the distal end of the second body component is downwardly
 inclined in side view and concave in plan view and may be provided with
 cushioning strips. The "tail" is arranged to engage the (right-handed)
 player's right leg at, or just above, the player's right knee and is
 configured so that as the player's right knee swings inwardly, when his
 arms have reached, or pass the centre of gravity of the aid, the forces
 applied by the knee to the aid will cause the tail of the training aid to
 move downwardly to be released from the knee.
 For a left-handed player, the "nose" will be secured to the is player's
 right leg and the "tail" will releasably engage the left leg.
 Referring now to FIG. 2, the training aid 10 is fitted between the knees
 101, 102 of the player 100, just above the respective knee joints. The
 length of the body 11 of the aid 10 is adjusted for a comfortable stance.
 The cross-head 17 (and pad 16) on the first leg 12 are secured to the left
 knee 102 (of a right-handed player) by the strap 20.
 As the player 100 makes the backswing of his club 110, the training aid 10
 maintains the knees 101, 102, and thereby the lower body 103,
 substantially stable, as the players arms 104, 105 go through the motion
 of the backswing.
 This places the left upper body side muscles in tension, to act as a spring
 on the downswing.
 On the downswing (see FIGS. 4 and 5), the aid 10 locates the knees 101, 102
 to provide correct body control and movement.
 As the golf club 110 approaches, or passes, the player's right foot 106,
 see FIG. 6, the knees 101, 102 are permitted to move apart to release the
 cross-head 19 (and pad 18) from the player's right knee 101. The aid 10
 drops free, suspended from the left knee 102 by the strap 20.
 The actual point in the downswing at which release of the aid 10 from the
 right knee 101 will occur will be variable but will usually fall in the
 range of the club 110 closely adjacent to, or passing, the right foot 106
 to a point mid-point between the player's feet 106, 107 (ie., adjacent the
 centre of gravity of the training aid 10).
 As shown in FIGS. 7 and 8, the player 100 is then able to complete his
 swing without interconnection between his knees, resulting in a more
 natural swing than is possible with the prior art aids hereinbefore
 discussed.
 As shown in FIGS. 9 to 11, the training aid 10 can indicate the type of
 faults in a golfer's swing.
 In FIG. 9, where the player's hips have swayed, the training aid 20 becomes
 locked between the player's knees 101, 102 as the right knee 102 moves in
 the direction of arrow A.
 In over-rotation of the player's hips, see FIG. 10, the training aid 10
 becomes locked between the player's legs and cross-head 19 (and pad 18)
 rides up the right leg, ie., to move in the direction of arrow B above the
 right knee 101 and be locked between the legs.
 In FIG. 11, if the swing is incorrect, the training aid 10 will remain
 locked between the knees 101, 102 as the downswing is completed.
 (In certain instances, errors in the downswing will cause the training aid
 10 to be released from the right knee 101 before the golf club 110 reaches
 the right foot 106.)
 In tests carried out by the inventor, it has been established that for golf
 swings, the training aid 10 maintains the lower body 103 substantially
 stable during the back swing and approximately the first half 30 of the
 downswing, the upper body (or torso) 108 being "twisted" like a torsion
 spring to provide power to the arms 104, 105, and thereby the club 110 (or
 bat) on the forward swing.
 As the training aid releases the player's knees 101, 102 in the second half
 of the forward swing, the knees are allowed to move, so that portion of
 the swing remains natural.
 As shown in FIGS. 9 to 11, the aid 10 can also indicate the problem(s) with
 the player's swing.
 The aid is easy to fit and can be easily reduced in size for transport or
 storage. The aid is also relatively inexpensive to manufacture and does
 not rely on any supplementary equipment.
 Various changes and modifications may be made to the embodiments described
 and illustrated without departing from the present invention.