Grab Your Tape Measure, Patent Issues on the Proper Way to Determine the Ideal Shaft Length

OK, you start by measuring:

(i) the length from the floor to the ankle joint (while wearing shoes of similar heel size to that of a golf shoe),
(ii) the length from the ankle joint to the knee joint,
(iii) the length from the knee joint to the hip joint,
(iv) the length from the hip joint of the shoulder joint,
(v) the length from the shoulder joint to the knuckle of the middle finger of the right hand,
(vi) you do the Hokey-Pokey, and you turn yourself around, that’s what it’s all about!

But seriously, according to the German inventor listed on USPN 7510490 titled “Method for Determining Length of the Shaft of an Individually Adapted Golf Club” those are the measurements you need to properly determine a golf club shaft length.

Check out these drawings:

The patent explains:

The invention concerns a method for determining the length of the shaft of an individually adapted golf club.

In conventional methods for determining the length of the shaft of an individually adapted golf club the height of the golfer and the distance between the ground and the wrist or fingertips of a golfer in a standing upright position is measured. Then, the length of the shaft is taken from a table including measurement values and corresponding length values.

It is the task of the invention to create a new procedure to determine the length of the shaft of an individually adapted golf club, which allows a more precise definition of the length of the shaft than the known methods.

The method according to the invention is characterized in that the lengths of body parts of a golfer, which are decisive for the height position of his hands above the floor in the address position and during the golf swing, are measured and the length of the shaft is calculated from the measured lengths and predetermined angles (A, B, C, D) between the body parts as well as a predetermined angle (E) between the arms and the shaft or a predetermined lie angle (.alpha..sub.7).

That means, the method according to the invention is based on trigonometry. The lengths of the body parts of a golf player which are influential for the height position of the hands above the floor in the address position and during the swing are measured. Pre-determined angles between the body parts as well as a pre-determined angle between the arms and the shaft allow to one calculate the length of the shaft. This process also allows a precise calculation of the lie angle.

In distinction from the prior art a more accurate calculation of shaft length is possible. It is also possible that the angles between the measured body parts can be chosen by the experience of the golf trainer, allowing a higher level of individuality.

The following measurements are taken, the length from the floor to the ankle joint (while wearing shoes of similar heel size to that of a golf shoe), the length from the ankle joint to the knee joint, the length from the knee joint to the hip joint, the length from the hip joint of the shoulder joint and the length from the shoulder joint to the knuckle of the middle finger of the right hand.

As the golfer adopts his address position (starting position) the player bends the spine forwards and a curvature of the spine will occur, shortening the distance between the hip and shoulder joints. If the measurements of the golfer are taken in a standing upright position, to accommodate for the curvature of the spine and the distance between the hip and shoulder joints, the taken measurement will be multiplied by 0.92 (or a similar factor).

The total length of the golf club is calculated from the above described process plus a second part of the shaft or end piece. The end shaft piece can be calculated from a characteristic hand measurement of the golfer with a given multiplication factor. Characteristic hand measurements would be the distance from the wrist joint to the tip of the middle finger. The multiplication factor is 0.73 or similar. Or with the thumb stretched away from the palm the distance from the end of the thumb or root of the thumb nail across the palm to the opposite side of the palm. In this case, the multiplication factor is one.

To make practical use of the measuring system a computer software can be used to either calculate mathematically the golf club length or the club length can be taken from a saved data base of golfers of all sizes and proportions.

Ahh, now I see my problem…. I have never properly accounted for the curvature of my spine!

Dave Dawsey  – Watching Golf Club Fitting Patents

PS – click here to check out other golf shaft inventions