WO2022152745A1

WO2022152745A1 - Inertial golf putter with a high centre of gravity

Info

Publication number: WO2022152745A1
Application number: PCT/EP2022/050533
Authority: WO
Inventors: Pascal FREZZA
Original assignee: Frezza Pascal
Priority date: 2021-01-16
Filing date: 2022-01-12
Publication date: 2022-07-21
Also published as: FR3118886B1; FR3118886A1

Abstract

The invention relates to a golf putter that improves smoothness of movement, golf club path, and distance control during putting. These improvements result from the weight distribution and inertia of the putter.

Description

High Center of Gravity Inertial Golf Putter

A putter is a golf club consisting of a grip to hold the club, a shaft and a head in contact with the ball at impact. In general, it is commonly accepted that the ideal putting movement would be similar to a pendulum with the center of rotation in the middle of the shoulders. The amplitude of the pendulum giving the force of the blow and therefore a rolling distance for each angle. Players try to get closer to this "ideal" movement by putting. A golf putter that improves smoothness of stroke, club path, and distance control when putting through its mass distribution and inertia. This is due to its mass and its particular mass distribution.

Putting is an essential part of the game in golf. About 40% of shots are made using a putter. The golf putter is made up of a grip, a shaft and a head that hits the ball. There are many theories about putting techniques but although there are as many players as there are putting techniques, it is commonly believed that a pendulum-like motion with limited hand action improves metering, consistency and roll quality of the ball. The speed of the greens, which has tended to increase in recent decades, has also had an impact on the way the ball is hit with the putter. The putting movement is basically a rotation of the axis linking the shoulders around the spine. Shoulders, arms, and club rotating around at "relatively" fixed angles.

The “relatively” is important. Indeed, several rotations can occur during the movement. They are related to the joints and in particular at the level of the shoulders, the elbows and the wrists. The elbows have only one degree of mobility and are generally easy to "lock", the player does not "pump" with the elbows. The other 2 axes of rotation, on the other hand, have a greater degree of mobility. The way the shoulders revolve around the spine is essential. Players often tend to putt with their arms and have the axis of the shoulders that do not revolve around the spine enough. Players often use weak muscles (arms) instead of strong muscles (back muscles). Current putters being light, this phenomenon is amplified. The hands are also sources of irregularity, too much pressure on the hands can generate parasitic movements, "jerks". We can present the movement of putting as 2 systems evolving with different axes of rotation:

The first system “Shoulder/arms/hands/putter” revolves around the spinal column which is the main axis of rotation. When the movement is regular the amplitude determines the force, and the orientation of the pendulum, the direction.

The second system is the putter which can rotate around the axis of the hands. It is a parasitic movement which can alter the precision. Hands that can control the orientation of the clubface relative to the main swing.

These two systems have a specific MOI (moment of inertia) with respect to each of the axes of rotation. Finally, no bibliography presents the coupling of these two systems and how the design of a putter can optimize them to improve the quality of putting. The first highlight today is the mass of the putters. If we exclude the "long putter" (length greater than 45 inches/114.3 cm), almost all putters have a mass of around 500 grams. Some counterweights (a few tens of grams) can be added to the head or the grip, but the mass of putters rarely, if ever, exceeds 700 grams.

If we break down the first “shoulder/arm/hands/putter” subsystem rotating around the top of the spine (see figure 1), into 2 subsystems “shoulder/arm/hands” and “putter » rotating around the same axis. By modeling and simplifying these systems (such as bars to which we assign the masses at the level of the centers of gravity for example), we obtain an MOI of the putter / shoulder axis lower than that of the arms / shoulder axis (MOI [putter] / Axis shoulder < ME [shoulder/arms/hands]/shoulder axis). (See Figure 1)

The moment of inertia represents the ability of a solid to resist movement around an axis, so the player now feels his arms more than his club when performing the movement. Instead of leaving the club free in its natural movement, like a pendulum, the player may have to manipulate it and knock it out of the plane. To have a perfectly straight trajectory and in the right direction when putting, that is to say without side effect imparted to the ball, it is necessary that the path of the club is at 0° at impact and that the face of the club either perpendicular to the trajectory at impact (see figure 2). This means that the tangent to the movement of the putter at impact and the desired direction are confused. If the club is too light in relation to the arms, the player will tend to handle the club and not let it follow its path causing an out or inside club path. In this case, with a face perpendicular to the target direction at impact it will generate a side spin, with a face perpendicular to the club path, it will generate a straight trajectory in a direction that is not that of the target (see figure 2). The orientation of the face at impact being the main criterion for the direction of the ball, the player consciously or unconsciously corrects the orientation of the face which often generates balls with side effects causing the ball to go off the correct trajectory . This is not a problem for the long game (driver and irons) where the trajectory of the ball is finally not or not very important compared to the point of arrival and the fundamental parameter is the orientation of the face with the impact. For putting, on the other hand, the trajectory is crucial because the ball must follow a precise path to fall into the hole. The spin generated in the ball is therefore fundamental in putting, although it is at very low ball rotation levels in putting compared to the long game. not in the hole. The "swing path", club path, is therefore the fundamental parameter to establish your level of putting. The higher the mass of the club, the more the club will remain naturally in its trajectory, which will promote a regular swing path (club path at impact) close to 0°, which is desired. If the mass of the putter is increased, the MOI of the putter relative to the shoulder axis will increase, the player will feel the club more relative to the arms, and this will improve the swing plane of the putter during the stroke. It is therefore necessary to increase the mass of current putters as much as possible, the limit being linked to the strength of the golfer.

To increase the MOI of the "shoulders/arms/hands/club" system relative to the main axis of rotation of the movement, some manufacturers have designed clubs with heavier or weighted heads. These "heavy putters" weighed up to 900 grams. In our simplified model, with such a putter, the moment of inertia of the putter becomes greater than the moment of inertia of the arms with respect to the axis of the shoulders (about 1.5 times greater). It is positive and sufficient to feel the weight of the club relative to the arm. The problem with these putters is that they greatly increase the MOI of the putter relative to the second axis of rotation that comes into play when putting, that of the hands. When the player putts, he blocks his wrists to avoid unnecessary rotation that is harmful to the quality and regularity of the movement. The higher the moment of inertia (MOI) of the putter relative to the hands, the more the player will need to force which will generate tension in the hands. It is this tension in the hands that can in particular generate movement of the clubface relative to the path of the club. Thus, in the case of the 900g putter with a weighted head, the MOI of the putter with respect to the axis of the hands is approximately more than 2 times greater than that of the standard 500 gram club (its center of gravity also being lower ). This will generate 2 times more resistance to the movement and therefore 2 times more force to provide, generator of parasitic movements at the level of the hands. This will be especially true for higher amplitude putts. The wider the movement, the more the club is parallel to the ground, and the greater the torque at the wrists, generated by the heavy putter in the head. We therefore come to the conclusion that the mass distribution of the putter must also be different. The moment of inertia decreasing with the square of the distance when approaching the axis of rotation, with a center of gravity of the club closer to the hands, the MOI of the putter relative to the axis of the hands will decrease, which is beneficial for consistency.

In the same way that if the MOI putter/hand axis is too high the player forces and this generates tensions and parasitic movements, when the MOI tends towards 0, the player has no problem turning the club around the axis of the hands. It is therefore necessary that the center of gravity of the putter is not at the level of the grip. If the counterweight of the grip fully compensates for the mass of the putter head, it becomes very uncomfortable and generates parasitic movements. If the height of the center of gravity goes up again, it is as if the putter was reversed. The mass passes over the hands which is of no interest. It is also a risk if the center of gravity is under the grip with a low hand position.

The couple “Mass of the putter/Height of the center of gravity of the putter” is therefore fundamental to the optimization of the movement for putting and the improvement of the path of the club. The dynamics of the movement around the two axes of rotation (shoulders and hands) is governed by the MOIs of the 2 systems with respect to the 2 axes of rotation mentioned. These 2 MOIs being strongly linked in particular by the mass of the systems and their mass distribution (in particular the position of the center of gravity of the putter). The parameters of mass and height of the center of gravity of the putter are therefore inseparable.

We therefore arrive at 4 inequalities governing the optimum design of the putter:

(1): ME putter/column-shoulders axis » ME shoulder-arms-hands /column-shoulders axis

(2): Putter mass < 5 kg

(3): MOI putter /Axe hands « MOI ‘conventional’ putter /Axe hands

(4): ME putter/hands » 0

By taking typical morphology and mass data, as well as those of conventional putters, the graph shown in Figure 10 is obtained.

Each of the inequalities limiting a portion of the putter's optimal design area. By graying out the uninteresting parts, we get the "I" zone, which is the optimal design zone.

By considering the simplifications used for the modeling in zone limits (calculation of the moment of inertia of the club or of the arms, morphology of the arms and ratio Larms/Lputter, position of the hands on the club in particular), we can consider that the design of the putter must move away from the zone limits. The further one moves away from the zone limit, the greater the gain will be, up to an optimum from which one approaches another zone limit and the performance of the putter is degraded. The representation of the zones is shown in Figure 11.

Zone A: The high mass of the putter improves the pendulum movement relative to the shoulders and promotes a fairer club path. The putter “tracts” and is more easily placed in its path. The mass distribution is not good and the center of gravity is too low (close to the putter head). This creates tension in the hands and possible manipulation of the putter which degrades the regularity of the shots and prevents the use of the potential of the putter linked to its mass.

Zone I: The high mass of the putter promotes a fairer “club path”. The putter “tracts” and is more easily placed in its path. The mass distribution is good and better than zone A. The tension in the hands is significantly reduced thanks to the lower MOI putter/hand axis, without being too weak as in zone B. The club is easy to "move" on its correct path at the start of the movement. Consistency is improved and the potential of the putter is fully utilized

Zone B: The high mass of the putter promotes a fairer “club path” compared to zone A. The putter “hauls” and gets into its path more easily. But compared to zone I, the mass distribution of the putter with a center of gravity at the level of the grip, and therefore under the hands, gives the impression that the “putter head has no mass”. The counterweight compensates all the mass. "balance" of forces in the hands means that the slightest effort can cause the clubhead to move out of plane. The putter head becomes extremely volatile. The regularity is degraded.

Zone C: The high mass of the putter promotes a fairer “club path”. The putter “tracts” and is more easily placed in its path. The distribution of mass with a center of gravity at the very top of the putter and above the hands is very uncomfortable and recreates tension in the hands linked to the mass above which degrades the regularity of the shots. This can happen if the center of gravity is at the level of the grip and the hands are in a low position. This area should be avoided

Zone E: The mass distribution of the club is good and limits the player's hand movements. However, the putter is not heavy enough. The player will feel the inertia of the arms more and will tend to pull the putter with his “muscles” and manipulate the putter rather than leaving it on his arc. An increase in the absolute value of the "club path" will cause spin on the ball even with a square face at impact

Zone X: Zone X is not represented on the graph. The mass of the putter becomes too high. It is easy to conceptualize that beyond a certain mass, the putter can generate fatigue and discomfort. This limit is linked to the strength of the person and it is difficult to precisely determine. The prototypes that were tested up to 3kg with adults were not in this zone. The X zone is not represented on the graph and begins beyond 5kg.

Within this “I” zone, an ideal design zone is obtained which would correspond to the majority of golfers. It is defined as:

1.5 kg < Putter mass < 5 kg

And: 60% < % Height of the center of gravity < 72%

The optimal golf putter for a majority of players would be at 2.3 kg and have a center of gravity height such as %Hcg = 0.68 with a grip stopping just above this center of gravity.

If we look at the state of the art, this “ideal” zone is not known and unidentified today. Market putters are almost all positioned on the lower left of the chart. This area is far from optimal and ultimately of little interest. 2 patents are interesting to note:

In US patent 5632691, the masses are positioned in the shaft, allowing to increase the mass and the height of the center of gravity of the club. The patent covers an area of mass between 0.5 kg and 1.05 kg as well as a position of the center of inertia Hcg between 31% and 55% of length relative to the ground (the patent reference is relative to the top of the club, the grip, and therefore an area between 45% and 69%).

In US patent 6966846, a zone different from the optimum zone defined according to the invention is used. The zone defined in US 6966846 covers a wide spectrum of putter mass and a much higher center of gravity height zone since it is located in the grip "the counterweight having sufficient mass such that the center of gravity of the club lies within the grip”. The zone recommended in US 6966846 is therefore at the level of the hands, that is to say where the MOI putter/hands axis is close to 0. It is therefore not in the optimal design zone of the putter as defined here. . It is interesting to note that the position of the center of gravity is defined there in relation to the grip which is approximate because the grip could be very long. By measuring in FIG. 5 of the cited patent the position of the center of gravity, this corresponds to a %height of the CG of 74% positioned at the level of the grip and at the level of the hands of the player.

Figure 12 presents the state of the art on the different design areas identified.

The high center of gravity requires a large mass of the grip and this is not without problems. Indeed, within the framework of a traditional putter the mass of the grip is weak, there is thus only one mass (head of club) fixed at an end. Summary of the invention

The invention relates to a golf putter having the characteristic of having a mass greater than 1.5 kilograms and less than 5 kilograms and a weighted grip such that the center of gravity (51, 52) is located above 60% of the total length of the putter (0.6*L) in relation to the ground (Fig.3) and below 72% of the total length of the putter (0.72*L) without being in the grip (4).

According to an advantageous embodiment, the golf putter has a handle such that its frequency in CPM (cycle per minute) is defined by the relationship: CPM>591-7.7*Handle length (in inches).

According to an advantageous embodiment: 1.5 kg <mass of the putter <4 kg, even more preferably 1.8 kg <mass of the putter <2.8 kg.

According to an advantageous embodiment: 0.62*L<Height of the center of gravity<0.72*L, even more preferably 0.64*L<Height of the center of gravity<0.70*L.

One embodiment of the invention is a golf putter having a grip, a shaft and a head. It has a mass distribution such that the center of gravity is above 60% of the total length of the putter (0.6*L) relative to the ground and below 72% of the total length (0.72*L). The center of gravity of the putter is not at the level of the grip but below when the putter is held vertically, upside down. This golf putter must have a mass between 1.5 kilograms and 5 kilograms. (See figure 3)

Detailed description of the invention

The expression "consists essentially of" followed by one or more characteristics, means that may be included in the process or material of the invention, in addition to the components or steps explicitly listed, components or steps which do not significantly modify the properties and characteristics of the invention.

The expression "between X and Y" includes the terminals, unless explicitly stated otherwise. This expression therefore means that the target interval includes the values X, Y and all values from X to Y.

The different embodiments, variants, preferences and advantages described for each of the objects of the invention apply to all the objects of the invention and can be taken separately or in combination.

In the present description the lengths are expressed in inches because it is the practice in the field of golf articles, it being understood that an inch represents 2.54 centimeters.

The position of the center of gravity of the putter is determined relative to the length of the putter when the putter is held upright, upside down, from the ground.

In the context of the invention, the putter has a mass (in the grip) at the end of the club. This modifies the natural frequencies of vibration of the system, as well as the amplitudes of vibration. Without any other design modification, the prototypes that have been designed, with a heavier grip in particular, are difficult to play. On impact, the club gives a feeling of too much flexibility. This sensation is amplified during off-center shots, with the impact of the ball away from the "sweet spot". This feeling of flexibility of the club is mainly due to sleeves having too low frequencies mounted on the putters of series. Or rather, the design of current putters does not require shafts with high frequencies. The frequency of the neck is today the main parameter to determine its rigidity. There are many studies on the sizing of club shafts (iron, driver, hybrids in particular) but very few have been carried out on putters. The speed of the low movement and the design of current putters (in particular their mass), not requiring it. Several prototypes of the putter of the invention were designed with different shafts. Vibration, and the sensation of flexing on impact are greatly reduced with shafts having increased rigidity. These sleeves are called "stiff", "Xstiff" extra stiff or XXXStiff (and more). It should be noted that manufacturers do not generally provide precise specifications (Frequencies in particular) allowing the rigidity of the handle to be perfectly defined. This frequency is determined today under the term CPM (cycle per minute) and depends on the length of the club. Although the process is not completely identical from one manufacturer to another, the weight attached to the end of the handle to make the measurements is generally around 260 grams. In the context of the invention, in order to limit the vibrations in the handle linked to the particular design of the putter, the minimum frequency in CPM of the handle must preferably be such that "CPM > 591-7.7* Handle length" (Length handle in inches). For example, for a 35 inch/88.9 cm (standard) putter shaft, the minimum CPM should be 321.

A prototype designed according to the invention was tested on several players having different levels (handicap 40, 10 and 3). A first series of 10 balls were putted with a traditional putter. A second set of 10 balls were putted with a prototype putter according to the criteria of the invention. The putter head was the same. The prototype putter was fitted with a heavily weighted grip, the prototype putter weighing 2.3 kg and with %Hcg = 0.68. The mass distribution being such that the center of gravity was at the top of the handle and below the grip from a height point of view. It was rigged and adjusted in length with a 9 iron Xstiff 130g adjusted shaft. The tests were performed using a measurement tool called SamPuttLab. This device makes it possible in particular to measure all the characteristics of the putting movement, with in particular: the "path at impact", the "face at impact", the position of the contact of the ball on the putter. A mark out of 100% is also calculated. The results are presented in figures 5, 6 and 7.

For each of the players the tests are conclusive. The club according to the invention allows a marked improvement in the path of the club when making the shot. We have seen an improvement in the average trend for all players, the "Path at impact" being halved on average and a very clear improvement in consistency, especially for experienced players (Index 10 and Index 3).

For the Index 40 player, the club path changes from 4.3° straight to 2.6° straight. And the consistency goes from 15% to 19% at SamPuttLab.

For the Index 10 player, the club path changes from 3.1° left to 1.3° left. And the consistency goes from 51% to 84% at SamPuttLab.

For the Index 3 player the club path changes from 0.8° right to 0.2° right. And the consistency goes from 53% to 75% at SamPuttLab.

According to US patent 6966846, the innovation lies in the fact that the center of gravity is located in the grip "the counterweight must be sufficient mass to cause the center of gravity of the entire club to be contained within the boundaries of the grip". Such a comparative putter was made by making the mass of the grip even heavier in order to position it under the hands. The performance of this putter, as described in US Patent 6,966,846 with a center of gravity in the grip, is degraded compared to the putter of the present invention, although it performs better than almost all of the putters on the market. We find here the notion of optimum design zone with respect to the torque [mass putter/height center of gravity] and the results of the tests are presented in FIG. 8. The club path of the player index 10 with the putter of the invention is 1.3° left and it went to 2.5% left with a putter having the center of gravity in the grip as described in US patent 6966846. And the consistency goes from 84% to 71% at SamPuttLab.

Another important factor that may have to be modified to take into account the mass of the putter of the invention is the angle of the shaft with the vertical when the head of the putter rests on the ground in its normal position at address, called a "lie". The rules of golf define a minimum angle of 10° where almost all clubs sold are 20°. Given the high mass of the putter, and to take maximum advantage of the “club pull” in its plan, the position at address must be reviewed if necessary. If the "lie" is not adapted, a good position generates off-center strikes on the face with a position of the club at impact which is not adapted. The results are shown in Figure 9.

Description of figures

FIG. 1A presents, during the movement carried out during putting, the various systems and axes of rotation involved in the context of this movement.

Number 10 is the axis of rotation around which the shoulders turn, which we will call the shoulder axis.

The number 12 is the axis of rotation around which the hands turn, which we will call the Hands axis.

The number 11 represents the system [shoulders/arms/hands] which revolve around the axis number 10.

The number 13 represents the system [putter] which rotates around the axis number 10.

Figure IB shows the player at address before hitting the ball.

Figure IC shows the movement made by the player lifting the club at the start of the movement, with the system [shoulders/arms/hands] rotating around axis 10 trying to prevent the system [putter] from rotating around axis 12 (wrists).

Figure 1D presents the movement made by the player who lowers the club and hits the ball with the system [shoulders/arms/hands] which rotate around the axis 10 trying to prevent the system [putter] from rotating around of axis 12 (axis of the hands).

Figure 2 shows the directions and spin taken by the ball in relation to the club path at impact, "path at impact", and the angle of the face at impact, "face at impact".

Trajectory of case number 21: For a face at impact of 0° and a path at impact of 0° the trajectory is perfectly straight in the direction of the hole. It's the perfect shot.

Trajectory of case number 22: For a face at impact of x° and a path at impact of x° the trajectory is perfectly straight but with an angle of x° with respect to the direction of the hole. Trajectory of case number 23: For a face at impact of -y° and a path at impact of -y° the trajectory is perfectly straight but with an angle of -y° with respect to the direction of the hole.

Trajectory of case number 24: For a face at impact of 0° and a path at impact of x° the ball will come out slightly to the right (between 0° and x°) with a lateral effect which will be slightly turning the ball to the left and a curved trajectory.

Trajectory of case number 25: For a face at impact of 0° and a path at impact of -y° the ball will come out slightly to the left (between 0° and -y°) with a side effect which will slightly turn the ball to the right and a curved trajectory.

Figure 3 shows the design of a conventional putter and the inventive putter with the center of gravity positioning area.

Number 1 is the head of the putter that hits the ball on the swing.

Number 2 is the handle. Number 3 is the grip of a “classic” putter. Number 4 is the grip of the putter of the invention.

Number 5 is the overall "L" length of the putter.

The number 50 represents in dotted lines the zone of the center of gravity of a "classic" putter between 20% and 55% of the length L.

The number 51 represents the center of gravity of the putter of the invention located in the dotted area between 60% and 72% of the length L.

The number 54 represents in dotted lines the zone of the center of gravity of the putter of the invention between 60% and 72% of the length L.

FIG. 4 represents the design of the putter of the invention with an optimal zone for positioning the center of gravity which would be located below the grip without being under the grip. Number 2 is the handle. The number 52 represents the example of an optimal position of the center of gravity of the putter within the zone defined between 60% and 72% of the length L. This is slightly below the grip zone 53 in order to have hands close to the center of gravity without the hands being at the level of the center of gravity.

The number 53 represents the grip area in dotted lines. The center of gravity of the putter should not be in this area.

Figure 5 shows the measurement results on the quality of the club path for a putter on the market, and the prototype putter designed according to the claims of the present patent. The player index being 40. We see in particular the strong improvement of the club path on the average tendency and the regularity. Average club path changes from 4.3° straight to 2.6° straight

Figure 6 shows the measurement results on the quality of the club path for a market putter, and the prototype putter designed according to the claims of the present patent. The index of the player being 10. We see in particular the strong improvement of the club path on the average tendency and the regularity. Average club path changed from 3.1° left to 1.3° left

Figure 7 shows the measurement results on the quality of the club path for a market putter, and the prototype putter designed according to the claims of the present patent. The index of play being 3. We see in particular the strong improvement of the club path on the average tendency and the regularity. The average clubpath changes from 0.8° straight to 0.2° straight hands according to the claims of US patent 6966846. The player's index being 10. We see in particular the degradation of the club path on the average tendency and the regularity in this second case.

Figure 9 presents the measurement results on the quality of centering of the strike for the prototype putter designed according to the claims of this patent with a modification of the "lie" (angle with respect to the vertical when the head of the putter rests on the ground) .

Figure 10 graphically represents the 4 inequalities used to define the ideal zone for the design of the putter.

Cg is the center of gravity of the putter,

L is the length of the putter,

Hcg is the distance between the center of gravity and the bottom of the putter (head), and %Hcg=Hcg/L.

(2): Putter mass < 5 kg

(3): MOI putter /Axe hands « MOI ‘conventional’ putter /Axe hands

(4): ME putter/hands » 0

Figure 11 shows 6 areas of putter design in relation to its mass and the % height of the center of gravity. Inside zone I is defined the Ideal zone.

The M zone is the zone where we find almost all the putters on the market.

Zone N is the zone defined by US patent 6966846.

Lz zone O is the zone defined in US patent 5632691.

Zone I is the ideal design zone defined by the present invention.

Claims

Claim 1: Golf putter having the characteristic of having a mass greater than 1.5 kilograms and less than 5 kilograms and a weighted grip such that the center of gravity (51, 52) is located above 60% of the total length of the putter (0.6*L) relative to the ground and below 72% of the total length of the putter (0.72*L) without being in the grip (4).

Claim 2: Golf putter according to claim 1 which has a shaft such that its frequency in CPM (cycles per minute) is defined by the relationship: CPM > 591-7.7*Shaft length (in inches).