GB2039749A - Improved practice golf club - Google Patents

Abstract

The club has a bulb (16) and battery (66) located in its head (14). An inertia switch is located within the handle of the club for completing the circuit containing the battery and bulb when the club is swung, there being an adjustment allowing for an initial setting of the switch to adjust its sensitivity. A pre-focussed (lens-end) bulb is preferred. Means (64) for controlling the current flowing in the circuit is provided to allow the brilliance of the bulb to be adjusted. <IMAGE>

Description

SPECIFICATION Practice golf club FIELD OF INVENTION The present invention concerns apparatus which is primarily intended to enable the user to obtain practice in swinging a golf club and addressing a golf ball correctly. In particular the apparatus allows the user or a coach instructing the user to check the correctness or otherwise of a user's swing and ball address.

BACKGROUND TO THE INVENTION AND PRIOR ART Applicant's British Specification No. 1270422 describes a practice golf club which consists of a hollow shaft, a club head fixed to one end of the shaft, an electric light bulb mounted in the club head and means housed in the shaft and axially slidable therein under the action of centrifugal force during the swinging of the club to engage a contact to close an electric circuit containing the light bulb.

Whilst this previous design of practice golf club has fulfilled the original expectations of this device, the Applicant has devised certain improvements which facilitate the manufacture and use of the practice golf club described in his prior patent specification. In the previous design of practice golf club the battery for powering the electric light bulb was located in the shaft of the club and this together with the associated mechanism for closing electrical contacts under centrifugal force during the swinging of the club tended to alter the weight distribution within the club significantly.

It was also found that in daylight conditions the lamp brilliance was generally insufficient to give a clear indication of the line of swing. Additional batteries to give more power merely aggravated the adverse weight distribution problem.

Whilst the locus of the moving light under appropriate conditions clearly indicated the line of swing, it did not indicate to the user, or to a coach instructing the user, whether the line of swing was correct for the position of the ball and for the particular stance of the player.

With these points in mind it is an object of the present invention to provide an improved practice golf club and apparatus for use therewith.

THE INVENTION According to one aspect of the present invention a practice golf club of the type claimed in Claim 1 of my British Patent 1270422 incorporates a recess in the head of the club into which at least one battery is removably fitted and access to the recess is gained by means of a replaceable member which can be secured in position to close off the entrance to the recess.

By incorporating the battery in the head of the club, so a larger and heavier battery may be used and more power is available for illuminating the bulb which in turn allows a brighter light to be obtained which greatly facilitates the use of the club during high level ambient lighting conditions.

Preferably means is provided for adjusting the current which flows when the circuit between the battery and the bulb is completed so as to control the amount of light emitted by the bulb. By providing a relatively high voltage battery and a relatively lower voltage bulb, the latter can be made to incandesce very brightly for a brief interval of time by reducing the resistance in the circuit and vice versa.

According to a preferred feature of the invention, a practice mat is provided for use with a practice golf club, the mat comprising a flat surface having marked thereon at least one straight line to denote the position of a user's left foot and another straight line marked thereon to indicate the line of swing along which the light spot produced by the incandescent bulb in the golf club head moves just before it addresses the ball, the position of the ball being denoted by the intersection of the two straight lines in the said surface. Use of the mat allows the user to more easily see whether his lie of stroke is correct.

Typically the practice mat is formed of material which can be rolled up to facilitate carriage and storage.

According to another preferred feature of the invention the position of the bulb in the head is on the line of sight from the user to the point on the head which the user ought to bring into contact with the bail on impact therewith.

A compromise position for the bulb can be selected compatible with the height of the average person using a club or a range of clubs may be provided for people of different heights with the bulbs located in the heads of the clubs as appropriate.

A further solution is to provide a bulb which can be adjusted in position in the head of the club so as to provide a range of different positions of the point of light in the head of the club as viewed by the user.

A preferred form of bulb is a lens end bulb which serves to concentrate the light from the filament in the bulb into a small spot and forms a beam of light to the user's eye.

In place of a lens end bulb a more conventional bulb may be located within the head of the club and a window provided in the club to contain a lens through which the light can pass and be focussed.

The invention will now be described by way of example with reference to the accompanying drawings.

IN THE DRAWINGS Fig. 1 is a side view of a practice club embodying the invention, Fig. 2 is an enlarged cross-section through the handle end of a club shown in Fig. 1 which is shown as partly an exploded view, and Fig. 3 is a cross-section through the head of the club shown in Fig. 1.

DETAILED DESCRIPTION OF DRAWINGS The practice club shown in Fig. 1 comprises an elongate shank 10 having a handle grip 12 at one end and a head generally designated 1 4 secured to the other end in known manner.

In accordance with the invention the head of the club includes a bulb 1 6 mounted so as to be visible by the user when the club is swung and positioned in the head so that the locus of the point source of light provided by the bulb 16 corresponds to the line of swing of the club so that the latter can be seen by the user during the swing before and after the point at which impact would occur to indicate to the user (and to a coach instructing the user) whether or not the line of swing is correct.

Access to the inside of the shank 10 can be obtained by removing an end cap 1 8 which is conveniently provided with a screwdriver slot or similar keying device.

Fig. 2 which is a partly exploded view illustrates the internal construction of the upper end of the club shank 10 which is hidden from view in Fig. 1.

The end cap 18 is integrally formed with a cylindrical plug 20 from which a screw-threaded rod 22 extends coaxially. Screwed onto the rod 22 is a helical spring 24 and screwed into the opposite end of the spring 24 is a contact slug 26.

All the component parts are formed from metal or are rendered conductive by means of a metalised coating. Adjustment of the length of spring screwed into the rod 22 determines the position of the contact 26 relative to a second contact 50 (to be described). This allows the club to be adjusted so that the light comes on as needed for variation of swing speeds.

The member 20 includes diametrically opposed lugs one of which is shown at 28 and is a sliding fit in a sleeve 30 which is formed with right-angled slots one of which is shown at 32 to form a bayonet fitting for the member 20. The lugs 28 engage in the slots 32.

The sleeve 30 is a sliding fit within a cylindrical metal tube which forms the shank 10 of the club.

The tube 10 tapers towards the lower end of the club in known manner but in the region of the handle grip 12 it is generally cylindrical or tapers only very slightly. The sleeve 30 is secured in position within the metal tube forming the shank 10 by means of two screws 34 and 36 shown in Fig. 2. Holes are provided in the wall of the tube 10 through which the screws 34 and 36 pass.

A washer or spacer 38 may be provided between the underside of the cap 18 and the aligned ends of the sleeve 30 and cylindrical tube 10.

Whilst the upper end of the sleeve 30 is open and the inside is dimensioned so as to receive the member 20 as a sliding fit, the lower end of the sleeve 30 is formed with a restricted exit aperture 40 and a tube 42 formed from electrically insulating material such as perspex or plastics material and having an enlarged head at its upper end 44 is introduced into the sleeve 30 from above so that the elongate tube 42 extends through the exit aperture 40.

A compression spring 46 is fitted between the shoulder 48 defining the restricted exit aperture 40 and the underside of the enlarged diameter head 44.

The upper end of the tube and the head 44 is open to receive the elongate contact assembly of rod 22, spring 24 and contact slug 26 which when in position, extend freely down the central core of the insulating tube 42.

At the lower end of the tube 42 is located a fixed metal electrical contact 50 having an insulated electrical conductor 52 soldered or otherwise secured thereto and in electrical contact therewith.

The distance which the conductive slug 26 extends down the length of the tube 42 is adjusted so that the slug 26 is normally held away from the contact 50. However the weight of the slug 26 and the resilience of the spring 24 is selected so that when the club is swung in a conventional manner the slug 26 is urged down the tube 42 under centrifugal forces so that it is brought into contact with the contact 50.

The tube 42 is located centrally within the tube 10 by means of resilient spacer rings typically of rubber one of which is shown at 54 in Fig. 2.

Referring now to Fig. 3, the head of the club designated by reference numeral 14 includes a cylindrical cavity 56 containing a screw-threaded fitting into which the bulb 1 6 is screwed. The fitting 58 inludes an insulated central terminal 60 which is engaged by the central conductive tip of the bulb 1 6 and is connected via an insulated conductor 62 and adjustable resistor 64 to the positive terminal of a battery 66 situated beneath the bulb in a second cavity 68 formed within the head of the club. A second insulated conductor 70 serves to connect the negative pole of the battery 66 to the lower end of the metal tube 10 which in known manner extends into the head.

The circuit is completed by means of the insulated conductor 52 which extends down the centre of the tube 1 0 and is connected at its lower end to the conductive screwed fitting 58.

A cover plate 72 is fitted over the cavity 68 to retain the battery 66 in position and screws (not shown) are provided to hold the cover plate 72 in position.

Although not shown, the variable resistor 64 may be located within the head so as to be accessible through a screwdriver slot or the like in the head to allow the resistor to be adjusted by inserting a screwdriver through the slot to engage a screwdriver slot in the variable resistor to allow the latter to be twisted and to have its resistance adjusted.

Furthermore although not shown the cavity 56 may be larger and the precise position for the fitting 58 within the cavity may be adjustable to allow the bulb 1 6 to be positioned so as to precisely lie on the line of sight between the eyes of the user and the line through the point in the striking surface of the head 14 which would be brought into contact with the ball when the latter is addressed correctly.

Although a variable resistor 64 has been shown and described, it is to be understood that the invention is not in any way limited to the use of a variable resistor and a fixed value resistor of appropriate resistance may be used in place.

Claims (10)

1. A practice golf club of the type claimed in Claim 1 of British Patent 1270422 characterised by a recess in the head of the club into which at least one battery is removably fitted and a removable member which can be secured in a position to close off the entrance to the recess to retain the battery therein.

2. A practice golf club as claimed in claim 1 in which means is provided for adjusting the current which flows when the circuit between the battery and the bulb is completed so as to control the amount of light emitted by the bulb.

3. A practice golf club as claimed in claim 1 or 2 in which the position of the bulb in the head is one the line of sight from the user to the point on the head which the user ought to bring into contact with the ball on impact therewith.

4. A practice golf club as claimed in any of claims 1 to 3 in which the position of the bulb which can be adjusted in the head of the club so as to provide a range of different positions of the point of light in the head of the club as viewed by the user.

5. A practice golf club as claimed in any of the preceding claims in which the bulb is a lens-endbulb which serves to concentrate the light from the filament in the bulb into a small spot.

6. A practice golf club as claimed in any of claims 1 to 4 in which the bulb is located within the head of the club and a window is provided in the club containing a lens through which light from the bulb can pass and be focussed.

7. A practice mat for use with a practice golf club as claimed in any of the preceding claims comprising a flat surface having marked thereon at least one straight line to denote the position of a user's left foot and another straight line to indicate the line of swing along which the light spot produced by the incandescent bulb in the practice golf club head should move just before it addresses the ball, the position of the ball being denoted by the intersection of the two straight lines in the said surface.

8. A practice mat as claimed in claim 7 which is formed from flexible material to allow it to be rolled up to facilitate carriage and storage.

9. A practice golf club constructed arranged and adapted to be used substantially as herein described with reference to and as illustrated in the accompanying drawings.

10. A practice mat for use with a practice golf club, constructed and arranged substantially as herein described with reference to and as illustrated in the accompanying drawings.