GB2103492A

GB2103492A - Golf club

Info

Publication number: GB2103492A
Application number: GB08124300A
Authority: GB
Inventors: David Lees Linning
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-08-08
Filing date: 1981-08-08
Publication date: 1983-02-23

Abstract

A golf training club has its shaft in two parts joined by a spring loaded link located immediately below the grip. This link can collapse by acting as an omni-directional hinge when subjected to bending moments above a threshold level, returning automatically to alignment when the bending moment falls below the threshold level. It also becomes more rigid under the action of a direct pull along the shaft. The threshold bending moment required to cause the link to collapse is adjustable. The link has an external flange (15) attached to the lower half of the shaft bearing on an internal flange (16) in a sleeve connected to the upper half of the shaft, and forcing these two flanges together by means of a spring. By adjusting the degree of compression of the spring the threshold bending moment required to cause the flanges to hinge can be varied. <IMAGE>

Description

SPECIFICATION This invention relates to golf clubs and it provides a new form of golf club suitable for training or practice purposes In a good golf swing the golfer pulls the club through the downswing allowing the wrists to act as hinges around which the club swings under the action of centrifugal force. In a bad golf swing the golfer, in addition to pulling, applies a bending moment to the club shaft right from the start of the downswing and this destroys any chance he might have had of making a successful shot.

The present invention is for a club which will respond to the application of excessive bending moment by temporarily collapsing, as illustrated in Figure 1. With a correct swing the shaft remains rigid and allows the golfer to execute his shot as with a standard club.

By using this club in practice the golfer is constrained to avoid "forcing" and more quickly senses the action that is called for if a proper golf shot is to be produced. The club also enables golf instructors to demonstrate effectively the fundamental principles of the golf swing.

Figure 1 shows a collapsible link located in a golf club shaft just immediately below the grip of the club.

Figure 2 and 3 show a cross-section of the collapsible link. The link comprises four parts as numbered in Figure 2.

Part lisa cylindrical sleeve 12 connected to the upper part of the club shaft by a strong and permanent bonding agent. It has a screw thread on its outer surface.

Part2 is a connecting sleeve 13 and has an internal thread so that it can be screwed on the outer thread of Part 1, and an internal flange 16.

Part3 is a tube 14 having a flange 15 which is strongly bonded to the lower part of the club shaft.

The flange 15 fits snugly within the connecting sleeve 13 and rests on the internal flange 16.

Part4 is a helical compression spring which forcer the two flanges 15, 16 together so that a threshold bending moment is needed to cause the flanges to make an angle with each other as shown in Figure 3.

The threshold bending moment required to cause the club shaft to collapse can be adjusted by altering the degree of compression of the spring. That is done by screwing Part 2 in or out of Part 1,As the downswing proceeds, centrifugal force on the club head increases substantially, pulling the two flanges firmly together and helping to maintain the rigidity of the club shaft appropriate to a correct swing auction.

The collapsible link described above has a number of features which are advantageous and relevant to its function. These are: 1. A threshold bending moment of adjustable magnitude is required to cause the link to collapse.

2. The collapsible link can give in any direction.

3. The link automatically re-aligns when the bending moment is removed.

4. Centrifugal force on the club head only serves to increase the threshold bending moment.

The most crucial part of the swing is the turn round at the top and the start of the downswing. It is here that the not so good golfer applies the wrong forces which lead to the temporary collapse of the spring link. The take-away from the address position is also a crucial part of the swing. At both of these stages in the swing the centrifugal force is zero, or negligably small, so that the threshold bending moment required to open the link is that set by the user when adjusting the screwed sleeve.

Although the club head can rotate relative to the grip if a sufficient torque is applied, this does not affect the practice club during an actual shot if contact is correctly made with the middle of the club head. The force that is applied to the golf ball is derived from the momentum of the club head and consequently there is no torque in a well struck shot to cause the club head to twist.

By adjusting the degree of compression of the spring, the threshold bending moment can be made small for chipping practice or larger for full shots.

The link can also be incorporated in a practice putter. In this case smoothness of action calls for avoidance of suddenly applied bending moments.

Snatching ata putt, a common fault, will produce collapse ofthe lightly adjusted link and train the golfer to adopt a smoother action.

The rules do not permit clubs of the type described to be used in normal competition, but they can be used on the practice ground or in practice rounds of golf, or in practice swinging without a golf ball.

1. A golf club responsive to the application of a threshold bending moment by temporarily collapsing at a link in the shaft of the club and restoring itself when the bending moment falls below the threshold.

2. A golf club as claimed in claim 1 in which the link is situated just below the grip of the club.

3. A golf club as claimed in claim 1 or 2 in which threshold of bending moment at which the club temporarily collapses is adjustable.

4. A golf club as claimed in any one of claims 1,2 or 3 in which the club can collapse omnidirectionally.

5. A golf club as claimed in any preceding claim in which the link is of a form such that it's rigidity is increased by a pull along the line of the shaft.

6. A golf club having a shaft in two parts and a link between the parts which link is temporarily collapsible by an applied bending moment and has its rigidity increased by a pull along the line of the shaft; the link comprising an inner sleeve (12) attached to one part of the club shaft and an outer sleeve (13) adjustable in position on the inner sleeve, a flange (15) attached to the other part of the club shaft and located in the outer sleeve, and a spring (part 4) inside the outer sleeve acting between the flange

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION This invention relates to golf clubs and it provides a new form of golf club suitable for training or practice purposes In a good golf swing the golfer pulls the club through the downswing allowing the wrists to act as hinges around which the club swings under the action of centrifugal force. In a bad golf swing the golfer, in addition to pulling, applies a bending moment to the club shaft right from the start of the downswing and this destroys any chance he might have had of making a successful shot. The present invention is for a club which will respond to the application of excessive bending moment by temporarily collapsing, as illustrated in Figure 1. With a correct swing the shaft remains rigid and allows the golfer to execute his shot as with a standard club. By using this club in practice the golfer is constrained to avoid "forcing" and more quickly senses the action that is called for if a proper golf shot is to be produced. The club also enables golf instructors to demonstrate effectively the fundamental principles of the golf swing. Figure 1 shows a collapsible link located in a golf club shaft just immediately below the grip of the club. Figure 2 and 3 show a cross-section of the collapsible link. The link comprises four parts as numbered in Figure 2. Part lisa cylindrical sleeve 12 connected to the upper part of the club shaft by a strong and permanent bonding agent. It has a screw thread on its outer surface. Part2 is a connecting sleeve 13 and has an internal thread so that it can be screwed on the outer thread of Part 1, and an internal flange 16. Part3 is a tube 14 having a flange 15 which is strongly bonded to the lower part of the club shaft. The flange 15 fits snugly within the connecting sleeve 13 and rests on the internal flange 16. Part4 is a helical compression spring which forcer the two flanges 15, 16 together so that a threshold bending moment is needed to cause the flanges to make an angle with each other as shown in Figure 3. The threshold bending moment required to cause the club shaft to collapse can be adjusted by altering the degree of compression of the spring. That is done by screwing Part 2 in or out of Part 1,As the downswing proceeds, centrifugal force on the club head increases substantially, pulling the two flanges firmly together and helping to maintain the rigidity of the club shaft appropriate to a correct swing auction. The collapsible link described above has a number of features which are advantageous and relevant to its function. These are: 1. A threshold bending moment of adjustable magnitude is required to cause the link to collapse. 2. The collapsible link can give in any direction. 3. The link automatically re-aligns when the bending moment is removed. 4. Centrifugal force on the club head only serves to increase the threshold bending moment. The most crucial part of the swing is the turn round at the top and the start of the downswing. It is here that the not so good golfer applies the wrong forces which lead to the temporary collapse of the spring link. The take-away from the address position is also a crucial part of the swing. At both of these stages in the swing the centrifugal force is zero, or negligably small, so that the threshold bending moment required to open the link is that set by the user when adjusting the screwed sleeve. Although the club head can rotate relative to the grip if a sufficient torque is applied, this does not affect the practice club during an actual shot if contact is correctly made with the middle of the club head. The force that is applied to the golf ball is derived from the momentum of the club head and consequently there is no torque in a well struck shot to cause the club head to twist. By adjusting the degree of compression of the spring, the threshold bending moment can be made small for chipping practice or larger for full shots. The link can also be incorporated in a practice putter. In this case smoothness of action calls for avoidance of suddenly applied bending moments. Snatching ata putt, a common fault, will produce collapse ofthe lightly adjusted link and train the golfer to adopt a smoother action. The rules do not permit clubs of the type described to be used in normal competition, but they can be used on the practice ground or in practice rounds of golf, or in practice swinging without a golf ball. CLAIMS

6. A golf club having a shaft in two parts and a link between the parts which link is temporarily collapsible by an applied bending moment and has its rigidity increased by a pull along the line of the shaft; the link comprising an inner sleeve (12) attached to one part of the club shaft and an outer sleeve (13) adjustable in position on the inner sleeve, a flange (15) attached to the other part of the club shaft and located in the outer sleeve, and a spring (part 4) inside the outer sleeve acting between the flange and the inner sleeve to keep the parts of the club shaft in line but compressible assymmetrically at a threshold bending moment to allow the link to collapse.

7. A golf club substantially as herein before described with reference to the drawings.