Title:
Golf trainer
Kind Code:
A1


Abstract:
A golf trainer (1) has a ground-engaging base (2) supporting a rail assembly (3) and a carriage (50) for guiding a golf club (typically a putter). Foot guides (12, 13) are of thin planar construction, having curved front edges and are configured and located to both indicate a good playing stance and provide support for the trainer (1) while the fronts of the player's feet are on them. The rail assembly (3) comprises a central post (25), and left and right side posts (26, 27). The base (2) comprises a central socket (30) for the central post (25), a left pair of sockets (31) for the post (26), and a right pair of sockets (32) for the post (27). The rail assembly (3) is secured to the base (2) by inserting the central post (25) in the socket (30), and simultaneously inserting the left post (26) in one of the sockets (31), and inserting the right post (27) in one of the sockets (32). By choice of socket, the user can secure the assembly (3) so that the stiffening web (21) is in a vertical plane, or has a configuration which is generally cylindrical about a vertical axis. A club carriage (50) comprises an elastomer grip (51) and a and a wheel (55) for rotation on the axle (54). The elastomer grip (51) comprises a central through-hole (56) for gripping the shafr, and the shape of the gripping element and of a connector (52) allow self-tightening in use.



Inventors:
Hourihan, James (County Tipperary, IE)
Moloney, Francis (Penarth, GB)
Mooney, Brian (County Dublin, IE)
Walsh, Christopher (Cardiff, GB)
Application Number:
11/272081
Publication Date:
06/15/2006
Filing Date:
11/14/2005
Primary Class:
Other Classes:
473/260
International Classes:
A63B69/36
View Patent Images:
Related US Applications:
20020010032System and method for bowling remotelyJanuary, 2002Stiteler
20050266935Game system and methodDecember, 2005Mabry et al.
20090062040Multi task, exercising, and sport, self propelled backboard, MTESBMarch, 2009Gayed
20060063615Training apparatus for passing a projectileMarch, 2006Richardson et al.
20100004076Multifunctional Protection System for a Sports GroundJanuary, 2010Hansez-gonne
20100016101SOCCER TRAINING AIDJanuary, 2010Domjen
20050119063Golf stroke training deviceJune, 2005Tupman et al.
20080026877Baseball data gathering deviceJanuary, 2008Neel
20070191127AUDIO DIGITAL RECORDING AND PLAYBACK DEVICE CONFIGURED TO CONVENIENTLY STORE AND PLAY AUDIBLE MESSAGES PERTAINING TO SPECIFIC GOLFING TECHNIQUES AND SITUATIONSAugust, 2007Sheen et al.
20060084533Table-tennis bat(pen-holding type)April, 2006Siow
20070275787Bowling ball having an RFID tagNovember, 2007Bouchard et al.



Primary Examiner:
LEGESSE, NINI F
Attorney, Agent or Firm:
JACOBSON HOLMAN PLLC (Washington, DC, US)
Claims:
1. 1-33. (canceled)

34. A golf trainer comprising a base, a guide rail supported on the base, and a carriage for gripping a golf club and or running on the rail.

35. The golf trainer as claimed in claim 34, wherein the rail is of non-uniform construction in cross-section, having different stiffness characteristics in different rail radial directions.

36. The golf trainer as claimed in claim 34, wherein the rail is of non-uniform construction in cross-section, having different stiffness characteristics in different rail radial directions; and wherein the rail comprises a flange or web extending in one direction only.

37. The golf trainer as claimed in claim 34, wherein the rail is of non-uniform construction in cross-section, having different stiffness characteristics in different rail radial directions; and wherein the rail comprises a flange or web extending in one direction only; and wherein the web or flange extends in a general direction towards the base.

38. The golf trainer as claimed in claim 34, wherein the carriage comprises a guide for running on the rail.

39. The golf trainer as claimed in claim 34, wherein the carriage comprises a guide for running on the rail; and wherein the guide is a wheel.

40. The golf trainer as claimed in claim 34, wherein the carriage comprises a guide for running on the rail; and wherein the guide is non-rotating and has a low-friction rail-contacting surface.

41. The golf trainer as claimed in claim 34, wherein the carriage comprises a guide for running on the rail; and wherein the guide is interchangeable.

42. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole.

43. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the gripping element is resilient and the through-hole has a smaller cross-section than that of a golf club when unstressed so that it is deformed and its resilience causes it to grip a shaft extending through it.

44. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the gripping element is resilient and the through-hole has a smaller cross-section than that of a golf club when unstressed so that it is deformed and its resilience causes it to grip a shaft extending through it; and wherein the gripping element is of a high friction material.

45. The golf trainer as claimed in claim 44, wherein the material is an elastomer.

46. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the gripping element is tapered inwardly and downwardly, and the connector comprises a sleeve to surround and engage the gripping element whereby the gripping element and the sleeve are self-tightening in use.

47. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the gripping element is tapered inwardly and downwardly, and the connector comprises a sleeve to surround and engage the gripping element whereby the gripping element and the sleeve are self-tightening in use; and wherein the gripping element has the outer configuration of the frustum of a cone.

48. The golf trainer as claimed in claims 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the carriage comprises a guide for running on the rail, and a connector linking the gripping element to the guide.

49. The golf trainer as claimed in claim 34, wherein the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole; and wherein the carriage comprises a guide for running on the rail, and a connector linking the gripping element to the guide wherein the guide is a wheel, the connector comprises a wheel axle, and the axle is longitudinally bifurcated to deform radially when it engages the wheel.

50. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means.

51. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means which allows connection of the rail to the base at different alignments to retain the rail at a desired orientation.

52. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means comprising a plurality of posts secured to the rail or the base and a greater number of sockets in the other of the base or the rail, whereby user selection of post-socket engagement sets rail orientation.

53. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means comprising a plurality of posts secured to the rail or the base and a greater number of sockets in the other of the base or the rail, whereby user selection of post-socket engagement sets rail orientation; and wherein the base comprises the sockets

54. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means comprising a plurality of posts secured to the rail or the base and a greater number of sockets in the other of the base or the rail, whereby user selection of post-socket engagement sets rail orientation; and wherein a plurality of the sockets are aligned, and there are additional sockets so that there may be rail curvature about a vertical axis.

55. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means comprising a plurality of posts secured to the rail or the base and a greater number of sockets in the other of the base or the rail, whereby user selection of post-socket engagement sets rail orientation; and wherein a plurality of the sockets are aligned, and there are additional sockets so that there may be rail curvature about a vertical axis; and wherein there is one socket located under a central portion of the rail and a plurality of sockets located under each end portion of the rail.

56. The golf trainer as claimed in claim 34, wherein the rail is removable from the base, and the base comprises a retainer for securing the rail to the base in a stowed position.

57. The golf trainer as claimed in claim 34, wherein the rail is removable from the base, and the base comprises a retainer for securing the rail to the base in a stowed position; and wherein the retainer is a snap-fitting socket.

58. The golf trainer as claimed in claim 34, wherein the rail is removable from the base, and the base comprises a retainer for securing the rail to the base in a stowed position; and wherein the base comprises a recess for the rail.

59. The golf trainer as claimed in claim 34, wherein the base comprises thin foot guides having a curved shape to generally conform to the fronts of a players feet when standing on them.

60. The golf trainer as claimed in claim 34, wherein the base comprises thin foot guides having a curved shape to generally conform to the fronts of a players feet when standing on them; and wherein the foot guides are located for a desired golfing stance.

61. The golf trainer as claimed in claim 34, wherein the base comprises a carrying handle.

62. The golf trainer as claimed in claim 34, wherein the rail is supported on end supports which allow rotation of the rail about its axis according to operation of the adjustment means.

63. The golf trainer as claimed in claim 34, wherein the rail is supported on end supports which allow rotation of the rail about its axis according to operation of the adjustment means; and wherein the rail is integral with a flange engaging a recess in the end supports.

64. The golf trainer as claimed in claim 34, wherein the rail is supported on end supports which allow rotation of the rail about its axis according to operation of the adjustment means; and wherein the rail extends beyond each end support, and the end supports are configured to allow the carriage to run on the rail beyond the end supports.

65. The golf trainer as claimed in claim 34, wherein the trainer comprises a rail adjustment means comprising a spindle threaded to a bush, mutual rotation of which cause movement of part of the rail to adjust its curvature.

66. The golf trainer as claimed in claim 65, wherein the axial direction of the spindle is adjustable to change the direction of the adjustment action.

Description:

FIELD OF THE INVENTION

The invention relates to golf trainers, particularly for training of players for putts or other short swing shots.

PRIOR ART DISCUSSION

Putting is one of the most important strokes in the game of golf. It is a simple stroke, requiring the player to strike the ball in a smooth continuous arc with good “follow through”. It is also important that the player strike the ball ‘squarely’, with the putter face at right angles to the. direction of movement. The -player should be able to replicate consistently a good putting stroke in order to score well.

US Patent Specification No. U.S. Pat. No. 4,634,131 (Vella et al) describes a putting trainer having an arc-shaped rail supported on a support structure. The rail is supported at each end by a mechanism having a wing nut pressing against a component for changing the orientation of the rail. Adjustment of the radius of the rail's arc is achieved by adjusting the tension applied by a wing nut to a link which in turn levers the end of the guide rail so as to produce a bow in the guide rail between two supports of rigid frame.

It appears that the Vella et al trainer would not be particularly reliable or easy to use as large forces are required to lever the end of the rail, and it would be difficult for the player to achieve a consistent orientation of the rail throughout its length.

Also, EP312287, U.S. Pat. No. 4,280,701, U.S. Pat. No. 2,653,025, and U.S. Pat. No. 1,960,787 describe golf trainers. However these trainers appear to be quite complex and bulky.

The invention is therefore directed towards providing an improved golf putting trainer.

SUMMARY OF THE INVENTION

According to the invention, there is provided a golf trainer comprising a base, a guide rail supported on the base, and a carriage for gripping a golf club and for running on the rail.

In one embodiment, the rail is of non-uniform construction in cross-section, having different stiffness characteristics in different rail radial directions.

In one embodiment, the rail comprises a flange or web extending in one direction only.

In one embodiment, the web or flange extends in a general direction towards the base.

In another embodiment, the carriage comprises a guide for running on the rail.

In one embodiment, the guide is a wheel. In an alternative embodiment, the guide is non-rotating and has a low-friction rail-contacting surface. The guide may be interchangeable.

In one embodiment, the carriage comprises a shaft gripping element having a through hole and a slot to allow it to be placed on a shaft with the shaft extending through the through-hole.

In one embodiment, the gripping element is resilient and the through-hole has a smaller cross-section than that of a golf club when unstressed so that it is deformed and its resilience causes it to grip a shaft extending through it.

In one embodiment, the gripping element is of a high friction material, in one embodiment being an elastomer.

In one embodiment, the gripping element is tapered. inwardly and downwardly, and the connector comprises a sleeve to surround and engage the gripping element whereby the gripping element and the sleeve are self-tightening in use. The gripping element may have the outer configuration of the frustum of a cone.

In one embodiment, the carriage comprises a guide for running on the rail, and a connector linking the gripping element to the guide.

In one embodiment, the guide is a wheel, the connector comprises a wheel axle, and the axle is longitudinally bifurcated to deform radially when it engages the wheel.

In one embodiment, the trainer comprises a rail adjustment means. The rail adjustment means may allow connection of the rail to the base at different alignments to retain the rail at a desired orientation.

In one embodiment, the adjustment means comprises a plurality of posts secured to the rail or the base and a greater number of sockets in the other of the base or the rail, whereby user selection of post-socket engagement sets rail orientation. In one embodiment, the base comprises the sockets.

In a further embodiment, a plurality of the sockets are aligned, and there are additional sockets so that there may be rail curvature about a vertical axis. In one embodiment, there is one socket located under a central portion of the rail and a plurality of sockets located under each end portion of the rail.

In one embodiment, the rail is removable from the base, and the base comprises a retainer for securing the rail to the base in a stowed position. The retainer may be a snap-fitting socket. In one embodiment, the base comprises a recess for the rail.

In one embodiment, the base comprises thin foot guides having a curved shape to generally conform to the fronts of a player's feet when standing on them. In one embodiment, the foot guides are located for a desired golfing stance.

In one embodiment, the base comprises a carrying handle.

In one embodiment, the rail is supported on end supports which allow rotation of the rail about its axis according to operation of the adjustment means.

In one embodiment, the rail is integral with a flange engaging a recess in the end supports.

In one embodiment, the rail extends beyond each end support, and the end supports are configured to allow the carriage to run on the rail beyond the end supports.

In one embodiment, the rail adjustment means comprises a spindle threaded to a bush, mutual rotation of which cause movement of part of the rail to adjust its curvature.

In one embodiment, the axial direction of the spindle is adjustable to change the direction of the adjustment action.

DETAILED DESCRIPTION OF THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:—

FIGS. 1 and 2 are perspective views of a golf trainer (without a club carriage) of the invention in operative and stowage positions respectively;

FIG. 3 in a perspective exploded view of the carriage, and FIG. 4 is a perspective view of the carriage showing how it is connected to a putter;

FIG. 5 is a perspective view of the full trainer in use;

FIG. 6 is a perspective view of an alternative trainer of the invention;

FIGS. 7 and 8 are diagrammatic end views showing the rail of the trainer of FIG. 6 at different positions; and

FIGS. 9 and 10 are perspective and cut-away views of a carriage.

DESCRIPTION OF THE EMBODIMENTS

Referring to FIGS. 1 to 5 a golf trainer 1 comprises a ground-engaging base 2 supporting a rail assembly 3 and a carriage 50 for guiding a golf club (typically a putter) using the rail assembly 3. The base 2 and the rail assembly 3 are of moulded plastics material.

The base 2 comprises left and right side pieces 10 and 11 interconnected by an integral transverse rail-supporting piece 14. Foot guides 12 and 13 are of thin planar construction, having curved front edges and are configured and located to both:

    • (a) indicate a good playing stance, and
    • (b) provide support for the trainer 1 while the fronts of the player's feet are on them.

The base 2 also comprises a carrying handle 15.

The rail assembly 3 comprises a rail 20, a vertical stiffening web 21, a stiffening rim 22, a central post 25, and left and right side posts 26 and 27. The base 2 comprises a central socket 30 for the central post 25, a left pair of sockets 31 for the post 26, and a right pair of sockets 32 for the post 27.

A club carriage 50 comprises an elastomer grip 51, a connector 52 having a sleeve 53 and integral axle 54, and a wheel 55 for rotation on the axle 54. The elastomer grip 51 comprises a central through-hole 56 for a club shaft and an elongate slot 57 to allow fitting onto the club shaft.

In use, the rail assembly 3 is secured to the base 2 by inserting the central post 25 in the socket 30, and simultaneously inserting the left post 26 in one of the sockets 31, and inserting the right post 27 in one of the sockets 32. By choice of socket, the user can secure the assembly 3 so that the stiffening web 21 is in a vertical plane, or has a configuration which is generally cylindrical about a vertical axis. This is achieved because the rail assembly 3 is relatively flexible when subjected to bending forces about a vertical axis, but is relatively stiff when subjected to bending forces about a horizontal axis.

The rail assembly 3 is arranged to have a substantially constant modulus along its length such that when bent about a vertical axis, it will generally assume a shape which lies in a substantially cylindrical surface with a vertical axis.

The posts 25, 26 and 27, and the sockets 30, 31, and 32 each have vertical axes and form a close and/or sprung fit which firmly retains the posts in a vertical orientation relative to the base, but also allow the posts to be disengaged from the sockets to allow adjustment or storage of the putting trainer. The axes of the three posts 25-27 are coplanar when the rail lies in a vertical plane, and the central post 25 engages in the central socket.30 and the posts 26 and 27 are in the forward sockets 31 and 32, which are coplanar. The additional, rearward, sockets 31 and 32 provide alternative positions for the posts 26 and 27. When the posts are engaged with these sockets, the rail 20 is held in a flexed position on a cylindrical surface with a vertical axis.

The rail assembly 3 is produced as a single polymer moulding, which has several advantages. Component and assembly costs are reduced. The assembly is strong and there is little unwanted movement resulting from looseness between component parts.

FIG. 2 shows the putting trainer 1 in a stowed position, which is convenient for storage or transport. The base 2 forms a recess in a generally horizontal plane, which corresponds to the shape of the rail assembly 3. Also, the post 25 snap fits into a socket 40, so that the assembly is securely retained. It will be appreciated that the trainer is compact and may be easily carried using the handle 15.

Referring particularly to FIGS. 3 and 4, the elastomer material has a relatively high friction coefficient and grips the contacting external surface of the putter shaft. The hole 56 in the elastomer grip 51 has a diameter, when unstressed, which is slightly less than the diameter of the putter shaft. The material of the elastomer grip 51 is accordingly deformed by insertion of the putter shaft and. the elastic spring characteristics of the elastomer material give rise to pressure between the contacting surfaces, which advantageously increases the friction grip and prevents relative movement between the carriage 50 and the putter during practice.

The elastomer grip 51 is formed as the frustum of a cone, and it is connected to the wheel 55 by the connector 52. This also comprises a grip support radial slit, which allows the assembled putter shaft and elastomer grip to be fitted into the grip support. The grip support radial slit is arranged to be sufficiently wide to allow the putter shaft to be passed sideways through it, to permit assembly to take place.

The axis of the guide wheel 55 axle is orientated at an angle to the axis of the elastomer grip 51 such that the axle is substantially horizontal when the putter is held at its normal inclination where it makes contact with the ball. This angle is somewhat less than 90°. The connector 52 comprises a single polymer moulding. The guide wheel 55 is mounted on the axle 54 and is free to rotate about it. The axle 54 is longitudinally bifurcated with a vertical slit. In its unstressed shape, its central region comprises the majority part of a cylindrical surface corresponding to the hole in the guide wheel and thereby provides a bearing surface for the guide wheel 55. The guide wheel 55 is made captive on this bearing surface by flanges at each end, including the outer bifurcated end. The flanges are also shaped such that the wheel can pass over them when the two bifurcated halves are momentarily forced together by squeezing them in a horizontal direction. The elasticity of the polymer material returns the bifurcated halves to their normal position when the momentary force is removed. The force exerted by the connector 52 on the putter P will tend to urge the elastomer grip 51 vertically downwards and the connector 52 vertically upwards, and will cause little or no deflection of the bifurcations, ensuring that the guide wheel 55 remains captive on the axle 54.

Referring now to FIG. 5, the trainer 1 is shown in use. The force exerted by the connector 52 on the putter tends to urge the elastomer grip 51 downwards and the connector 52 upwards, advantageously increasing the pressure between the contacting surfaces which advantageously inhibits relative rotational movement between the parts. It also prevents further relative axial movement between the parts.

The grip support may be formed with a relatively rigid construction, with the friction gripping force between it and the connector substantially relying on elastic deformation of the elastomer material when the frustum surfaces are pushed one into the other. Alternatively, the grip support may be formed with a relatively elastic construction, with its internal surface elastically deflecting and enlarging when the frustum surfaces are pushed one into the other. In this instance, the tendency for the grip support to elastically return to its unstressed shape is advantageously used to increase the friction force between the contacting surfaces.

It will be appreciated that the trainer 1 is of simple and robust construction, while at the same time allowing very effective golf running/stroke training in a versatile manner. The golfer is guided for both stance and also stroke in a simple and clear manner. Also, because it is so compact, it may be easily carried to a desired location for use where desired.

Referring to FIGS. 6 to 10, a putting trainer 100 comprises a base 101 to which are secured left and right end supports 102 and 103. The end supports support a guide rail 105, and the guide rail is also directly connected at its centre to the base by a rail adjustment mechanism 110. Adjacent to each end, the guide rail 105 is supported on a rail seat 115 which is located on the relevant end support. In this embodiment the guide rail 105 has an effective length extending a short distance beyond the end supports.

The base 101 comprises left and right foot recesses 120 and 121 to allow the player to stand in comfort with guidance for the correct feet positions for a good playing stance. The base 101 also comprises fixing apertures 125 to allow the trainer to be secured in place on the ground using golf tees.

Each of the end supports 102 and 103 is connected by, an end support hinge 130 to the base 101. The end support hinge 130 is held in an upright position by a hinge locking clip which disengages when depressed. Thus, the trainer can be readily collapsed for storage or transport by removing the rail, depressing the hinge locking clip and rotating the end supports downwardly to lie flat on the base.

The rail adjustment mechanism 110 comprises an externally threaded support member 140 which is connected perpendicularly below the centre of the guide rail. The threaded support member 140 engages with an internally threaded bush 141 which is held between two curved bush support clips 145. The bush support clips are located at the distal end of a cantilevered support arm 142 which is connected to the base 101. The threaded bush 141 is operable to be manually rotated between the two curved bush support clips 145, such rotation causing the threaded support member 140 to be drawn downwards or upwards as required to set the curvature of the guide rail.

The threaded support member 140 and the threaded bush 141 can be readily disconnected from the cantilevered support arm 142 by manually prising the curved bush support clips apart and withdrawing the threaded bush 142 sideways through the aperture. This provides a convenient means for disconnecting the rail when the trainer is folded for storage or transport. The bush support clips are flexible and are moulded with a pre-assembled diameter which is slightly less than that of the threaded bush such that the assembled threaded bush is securely gripped. The threaded bush 141 is also provided with flanges on its upper and lower rims which transmit the longitudinal forces, originating from the rail, to the upper and lower edges of the clips.

The cantilevered support arm 142 is operable to move within curved tracks on the base which allows the plane of the guide rail curve to be varied between a vertical orientation and an orientation of about 15° to vertical.

The adjustment mechanism of this embodiment may, with some modification readily appreciated by those skilled in the art, be adapted for use with the trainer 1. In this case the mechanism may adjust curvature about a vertical axis.

Referring particularly to FIGS. 7 and 8, the cross section of the guide rail, in the region of the rail seat 115 on the end support 102, comprises an upper circular portion 150 connected to a lower flange portion 151 with small side protuberances on its lower region. The guide wheel 160 runs on. the upper surface of the circular portion 150 of the rail and the lower surface of the circular portion of the rail is supported on corresponding surface on the rail seat 115. The flange 151 is located in an aperture 152 in the rail seat.

The rail 105 is produced by polymer extrusion with the illustrated cross-section, and the polymer is preferably PVC. The upper surface of the rail, where contact is made with the wheel, may be patterned during the extrusion process. This may be achieved by use of patterned rollers positioned downstream of the exit from the extrusion machine.

The drawings show a guide wheel 160 and how the wheel can roll along the rail and pass over the rail seat without making contact with it. FIG. 8 shows a similar view to FIG. 7 but with the rail and wheel inclined at an angle corresponding to the maximum inclination permitted by. the rail adjustment mechanism. The wheel remains operable to roll along the rail and pass over the rail seat without making contact with it. The rail continues to be supported by the rail seat. The aperture in the rail seat is sufficiently wide to allow inclination of the rail with. corresponding displacement of its flange and protuberances.

It will be appreciated that the contact point between the rail and the rail seat will change as the curvature of the rail is changed. Accordingly, the rail is displaced relative to the rail seat as the curvature is changed and the central position of the rail on the trainer is maintained by its central connection to the rail adjustment mechanism. It will also be appreciated that the orientation of the surface of the rail in contact with the rail seat will change as the curvature is changed. This is accommodated by the provision of a slightly convex curved surface on the rail seat, arranged such that its central portion makes contact with the rail when the rail is in the mid position of its range of curvatures. The region of contact between the rail and the rail seat will move slightly inwards as the radius of curvature of the rail is decreased and will move slightly outwards when it is increased.

The protuberances on the flange 151 advantageously prevent the rail from lifting out of the apertures in the rail seat. However, the rail can be readily removed by disconnecting the rail adjustment mechanism and longitudinally sliding each end of the rail out of the relevant aperture.

This rail connection method of the invention has several advantages. It is economic to produce since it requires no additional components or moving parts. Its simple design provides a robust and durable construction. It is operable to allow simple three-point bending which causes the rail to accurately take the shape of an arc of a circle.

Is should be noted that in both illustrated embodiments there is greater stiffness for curvature about a horizontal axis (in the substantially vertical plane) than about a vertical axis (substantially horizontal plane). This provides greater strength and durability than if the rail had uniform bending stiffness in all directions.

The centre of the rail is connected to the threaded support member of the rail adjustment mechanism. Where an extrusion is used, the support member is connected to the flange and protuberances on the underside of the rail. Where the rail and the support member comprise polymer components, the connection can be made by any of the known processes for connecting such materials, such as ultrasonic welding, bonding with an adhesive, or use of metal clips, rivets or screw fasteners. Grips may also be moulded on the connecting end of the support member, which engage the protuberances on. the extrusion .and add mechanical strength to the connection.

Force is applied upwards to the rail at each end under the circular portion of its cross section and downwards from the connection to the protuberances at the lower end of the flange 151. Since the downward force is at a lower position than the upward forces, even when the rail is straight, this promotes stability in the rail 105. throughout its range of curvature. As curvature increases, the upward forces are applied at points which are increasing higher relative to the downward force, and rail stability increases even further.

The use of an extruded polymer rail presents several advantages. It is economic to produce and requires little investment in tooling. It allows use of a profile with a closed hollow section, which provides a relatively large and strong section with minimal material content. It is produced by a continuous process which can ensure that its mechanical properties are consistent along its length. This is important in ensuring that three point bending accurately produces a curved rail in the form of a portion of the circumference of a circle.

In an alternative embodiment, the rail comprises a polymer injection moulding which may be similar in cross section to the extruded rail except that the closed hollow circular portion is no longer possible. It may be replaced by a solid shape or a shape with open grooves or channels. The shape should remain operable, over the range of inclination angles required by the trainer, to support the wheel on its upper region and to be supported by the rail seat at its lower region. A shape with open grooves or channels is preferred because a relatively large solid shape is wasteful of material and may present cooling difficulties in the production process. Where the rail and the support member are produced by an injection moulded process, they can be produced as a single integral component.

The rail may be provided straight or curved when unstressed. Where polymer material is used, a straight rail may be produced directly by either the extrusion or injection moulding process. Where a curved rail is used, it may be produced directly by the injection moulding process but will require a further curving process where an extrusion is used.

Where the rail is curved when unstressed, it eliminates the force required to get it from a straight condition to the commencement of the range, i.e. the largest radius of the range. It also reduces the force required to traverse the full range of radii, because it starts from a mid position. The reduction in force can be used to reduce the size and cost of the rail adjustment mechanism and other related components. For a given rail adjustment mechanism, the reduction in force can be used to provide a rail with a greater modulus that would otherwise be possible, thereby allowing use of a stronger and more rigid rail.

A putter carriage (or guide) 170 is shown in FIGS. 9 and 10. This is for the trainer of FIGS. 6 to 10, however it may equally be used with the trainer of FIGS. 1 to 5. The carriage includes a tension rod 171 which passes through its centre. The tension rod comprises an external thread on one end and a hook 172 on the other end. The hook 172 co-operates with a fixed half grip 173, which is integral with or connected to a hollow spindle 174. The guide wheel 160 is mounted on the hollow spindle, about which it is free to rotate. The tension rod 171 passes through the hollow spindle 174 and its threaded end protrudes from the end opposite the connection to the fixed half grip 171. A slot is provided in the fixed half grip which allows passage of the bends in the hook shape permitting the moving half grip to move close to the fixed half grip. A guide tightening knob 175, comprising an internal thread, is screwed along the threaded end of the tension rod, drawing the moving and fixed half grips together. The slot in the fixed half grip 173 prevents relative rotation of the moving half grip 172. The hollow spindle 174 is made slightly longer than the axial length of the wheel, ensuring that the tightening knob bears against the hollow spindle and not against the wheel.

The tension rod is made from steel of circular cross section, suitably protected from corrosion, for example by plating. The inside surface of the hook 172 is partly deformed such that, where it meets the gripped putter shaft, the rod presents a surface which forms part of a cylinder which is approximately coaxial with the putter shaft. This avoids point contact between the tension rod and putter shaft which might otherwise damage the shaft when the grips are tightened. As a further protection for the putter shaft, the hook 172 is covered with a sleeve of resilient elastomer material. Optionally, the inside surface of the fixed half grip may also comprise an elastomer material, possibly in the form of an elastomer moulding fastened or bonded to the inside surface of the polymer moulding. An elastomer material will tend to provide a better grip than a polymer material for the same applied force. The hollow spindle and fixed half grip comprise a single polymer moulding. The wheels also comprise polymer mouldings. The tightening knob comprises a polymer moulding with a metal threaded insert.

The carriage 170 is also operable to allow ready removal and substitution of one size wheel by another size. This presents the possibility of providing the trainer with a range of wheels which are suitable for different levels of player skill. Wheel changing is achieved by unscrewing the tightening knob from the end of the threaded end of the tension rod. The wheel can then be withdrawn from the hollow spindle and replaced with another. The tightening knob is screwed back into position. The guide 170 provides many advantages. It is strong and durable. The polymer or elastomer components are not subject to significant tension or bending stress as the guide is tightened on the shaft. The metal components are subject to substantially direct forces which are well within their strength capabilities. The carriage provides a tight and secure grip which is operable to ensure that the putter shaft will not slip during play. In addition, the carriage gives minimal visual obstruction of the putter face and ball during play since only the hook end is positioned on the playing side of the putter shaft. It also allows ready connection to and disconnection from the putter shaft and allows ready changing of wheel types. Furthermore, it is economical to produce.

The wheel 160 has a groove between two wheel flanges. The flanges are tapered inwardly and are operable to prevent the direction of the wheel axis deviating from a direction perpendicular to the direction of the rail axis. This is because the distance between the flanges is such that the rail is engaged by both flanges.

It will also be appreciated that the rail adjustment mechanism allows consistent inclination adjustment exactly half way down between the supports. There is no danger of the rail having a twisted or warped plane, which would arise if it had a separate adjustment at each end.

Another advantage of the carriages is that, allowing ready use of wheels with different groove widths, they may be optimised to suit the standard of the player. Typically, a player would start with deep flanges so that the wheel straddles the rail to the maximum extent for most comprehensive stroke constraint. As the player progresses, a wheel with a reduced flange may be used to reduce the area of contact with the rail thereby requiring the player to use more skill to keep the stroke on the correct path in contact with the rail.

The trainer may also comprise a positioning member which is used to ‘square’ the putter face relative to the trainer and which may also be used to position the ball in a consistent position. The positioning member may be provided with an array of parallel grooves which allow it to be clipped under the front edge of the trainer in a range of positions, each of which is at right angles to the length of the trainer. A putter face alignment member is fitted to the positioning member and comprises a vertical face which is at right angles to the length of the trainer. This alignment member can be located in one of two positions on the positioning. member by means such as corresponding projections and holes in the two components, these positions being provided to accommodate left and right handed players. Each of the two positions allows the putter face to be squared against the face of the alignment. member with the contacting faces at the centre of the trainer where the swing arc is at, or close to, its lowest point.

While the trainer has been described for putting training, it may also be used for training of chipping or other golf shots.

In a further embodiment, the trainer may have an adjustment mechanism incorporated in one or both end supports. In this embodiment the rail may be supported centrally by a fixed support or by an adjustment mechanism. In common with the illustrated embodiment the rail is supported at its centre, and so forces applied centrally or at the end supports are much lower than required in the prior art. Also in common with the illustrated embodiment the forces applied by the end supports will be substantially opposite to that applied by the central support. Thus, in both embodiments the adjustment mechanism(s) is/are operable to decrease the rail's radius by applying opposing forces away from each other between the central and end supports, and to increase its radius by applying opposing forces towards each other between the central and end supports.

It is also envisaged that, for all embodiments, the wheel may be replaced by a non-rotating low-friction grooved guide which runs on the rail. Such a guide may be integral with the part which engages the club shaft. This reduces the number of parts and in general simplifies the overall trainer. Also, the wheels may be interchangeable.

The invention is not limited to the embodiments described but may be varied in construction and detail.