Mid-shafted driver weighting mechanism

Abstract

A mid-shafted golf driver weighting mechanism is disclosed that improves swing stability, energy transfer, and impact consistency. The system positions a removable or adjustable mass at an intermediate location along the shaft rather than solely within the clubhead or grip. By shifting weight toward the shaft's midpoint, the mechanism reduces rotational torque during the downswing, enhances control over the clubface orientation, and promotes a more stable swing path. The configuration may include interchangeable weight cartridges, sliding collars, or internally housed masses that allow fine-tuning of the club's balance and moment of inertia. This design enables golfers to customize feel and performance for different swing speeds or desired shot shapes. The mid-shaft weighting approach provides a versatile alternative to traditional clubhead-only weighting systems while maintaining compliance with equipment rules.

Description

BACKGROUND OF THE INVENTION

[0001] Field of the Invention: The present invention relates generally to golf club heads, and more particularly to a golf driver having a centrally shafted design with adjustable weighting mechanisms to control ball flight. The invention addresses the needs of high-handicap or beginner golfers for improved accuracy and reduced shot dispersion.

[0002] Description of the Prior Art: Traditionally, driver-type golf clubs are “heel-shafted,” meaning the shaft attaches at the heel side of the club head (the end of the head closest to the golfer). In such designs, the club face is offset from the shaft axis, which can contribute to dynamic instabilities for amateur players. Many beginners struggle with shots that curve severely (e.g., slices to the right for a right-handed player), partly due to an open club face at impact and off-center strikes that impart sidespin. High-MOI designs have helped, but the inherent heel-shaft torque remains a source of error.

[0003] Center-shafted club designs have been proposed in the past, primarily in the context of putters and a few experimental woods. For example, a center-shafted wooden driver was patented as early as 1896 by Roy Sweny, sometimes referred to as a “horse's-hoof” club. That design placed the shaft attachment approximately in the center of the club head, a radical departure from the traditional heel-mounted persimmon woods of the era. While historically interesting, such early center-shafted woods lacked modern features like perimeter weighting or movable mass.

[0004] In more recent decades, golf club manufacturers have focused on adjustable weighting systems in drivers to help players tune ball flight. Numerous patents and products have introduced movable weight assemblies in driver heads, allowing the center of gravity to shift laterally or vertically. For example, certain prior designs describe a driver head with multiple weight-receiving cavities spaced between the toe and heel, enabling the golfer to adjust the lateral CG position. This and other prior art drivers demonstrate that altering weight placement can influence draw / fade or spin / launch bias. However, these clubs retained the traditional heel-shaft configuration.

[0005] However, all of the aforementioned modern adjustable-weight drivers share the conventional heel-shafted architecture. The hosel and shaft are located on the heel side of the head, meaning the shaft's axis is offset from the club head's sweet spot. As a result, the club head is not balanced about the shaft; there is an inherent moment arm between the line of the swing (through the shaft) and the center of mass of the head. This offset can induce or exacerbate club head twisting during the swing and at impact.

[0006] Prior efforts to mitigate these issues include designs like the Cleveland VAS woods from the mid-1990s, which featured an “inset” hosel that moved the shaft attachment slightly more toward the center of the head (though not fully centered). The theory behind the Cleveland VAS was to help square the club face at impact by reducing the hosel offset. Contemporary reviews noted that while it was unconventional, the design did have a positive effect on performance, validating the idea that shifting the shaft toward center improves forgiveness. Still, even that design was not fully central and lacked adjustable weighting.

[0007] Need for the Invention: Beginner and high-handicap golfers continue to struggle with inconsistent drives, often characterized by excessive left / right dispersion (slices or hooks) and a lack of confidence in keeping the ball in play. Even as adjustable-weight drivers have become mainstream, these are typically marketed to all skill levels and tuned by advanced players or fitters; they are not specifically configured as a training or game-improvement tool for novices. A golfer with a pronounced slice or inconsistent launch angle is left with little equipment-based recourse.SUMMARY OF THE INVENTION

[0008] The present invention provides a golf driver club head with a centrally located shaft connection and adjustable weighting means designed to collectively reduce off-line shot dispersion and tailor ball flight for the individual golfer. In one aspect, the invention is a golf club comprising a hollow metal wood-type driver head having a crown, sole, face, toe, heel, and rear; a shaft connected to the head at a central attachment point on the crown substantially equidistant from the toe and heel; and a plurality of weight receptacles positioned at the perimeter of the head.

[0009] Axis-relative weighting control: Repositioning weight across the shaft-axis plane toggles shot-shape bias (draw↔fade); repositioning along the face-normal depth toggles MOI / launch (rear↔forward). This enables both bias tuning and trajectory tuning using the same head without changing the shaft or loft settings.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates a rear club head with weighting placements and configurationsDETAILED DESCRIPTION OF THE INVENTION

[0011] Terminology. As used herein: “substantially central” refers to the shaft (hosel) axis intersecting the face within ±10% of the face width and within ±10% of the face height measured from the geometric face center; “shaft-axis plane” refers to the vertical plane containing the shaft axis and the intended target line projected from the face center; “perimeter” refers to regions of the head whose local center of gravity lies at least 60% of the maximum inscribed radius from the head's central vertical axis; and “face-balanced about the shaft axis” refers to the static torque about the shaft axis at address being below a threshold indicating no preferential opening / closing moment.

[0012] Measurement Protocol. Unless otherwise specified, performance comparisons described herein are made at matched loft and shaft model, using the same ball, with swing-speed bands of 95±2 mph and 110±2 mph, and at least 10 shots per configuration. “Offline dispersion” is measured as lateral deviation at carry (or normalized to 200 yards). “Closure rate” is obtained from high-speed capture or radar-derived face angle rate over the last 50 cm before impact. Reported deltas are arithmetic mean across shots.

[0013] Club Head Structure. Referring to FIGS. 1-3, the club head includes a front striking face, crown, sole, toe, heel, and a rear portion opposite the face. A reinforced tubular hosel is integrally formed in the crown at a central location such that its axis intersects the face within the ±10% tolerance of the geometric center.

[0014] Face-Balancing Effect. The central hosel placement yields a mass distribution substantially symmetric about the shaft axis; as a result, the head resists twisting and maintains a squarer face orientation through impact. Compared to heel-shafted drivers of equivalent loft and head volume, closure rate decreased by approximately 3% and toe-strike lateral deviation decreased by approximately 20%.

[0015] Perimeter Weighting System. The head incorporates a plurality of weighting locations distributed around its perimeter. In a preferred embodiment, three non-colinear receptacles are provided at the heel, toe, and rear regions, respectively. Each receptacle accepts an interchangeable weight member (e.g., cartridge or screw) of selectable mass. Alternative embodiments may use two receptacles (e.g., heel and toe) or four or more receptacles.

[0016] Axis-Relative Adjustments. Moving a heavier weight across the shaft-axis plane toggles shot-shape bias: heavier heel weight promotes draw bias; heavier toe weight promotes fade bias. Moving mass rearward increases MOI about the vertical axis, raising launch and increasing forgiveness, while moving mass forward lowers spin for a more penetrating trajectory. Rear-max configurations increased launch by about 1-2 degrees and added ~100-500 rpm spin for slower swings; forward-max reduced spin by ~500 rpm for faster swings.

[0017] Example Use (Slice Correction). For a right-handed slicer, a club-fitter installs a heavier heel weight and a lighter toe weight, shifting CG heel-ward. The effect is twofold: (1) face-closure assistance, and (2) corrective gear-effect on toe strikes. In testing, a golfer with +600 rpm fade sidespin achieved an average of −150 rpm draw sidespin with the heel-heavy configuration, effectively neutralizing his slice.

[0018] Calibration / Training Method. FIG. 5 outlines a calibration method: collect baseline launch-monitor data; configure weights across the shaft-axis plane to exaggerate a corrective bias; have the golfer hit shots; then iteratively normalize toward a playable configuration until dispersion is reduced by ~20% relative to baseline or side-spin magnitude is reduced below ~200 rpm.

[0019] Manufacturing and Embodiments. The club head can be manufactured via casting or forging of the shell followed by machining of the receptacles. Reinforcement ribs may connect the central hosel and weight receptacles. Head sizes may be up to 460 cc. Variants include a training driver with extreme perimeter weighting or fairway-wood versions with scaled designs.

[0020] Compliance Considerations. If a fully center-shafted driver is deemed non-conforming under equipment rules, the invention may be offered as a training or fitting device. A near-center embodiment (slightly offset beyond regulatory minimum) can retain functional face-balancing benefits while conforming.

[0021] Summary. Integrating a central hosel with perimeter adjustable weighting yields a driver that reduces dispersion for high-handicap golfers, while enabling targeted trajectory tuning. Prototype testing demonstrates consistent spin, launch, and dispersion improvements.

Claims

1. A golf club for driving a golf ball, comprising:a club head having a body with a face, a crown, a sole, a toe end and a heel end;a hosel on the crown, the hosel axis intersecting the face within ±10% of the horizontal midpoint and ±10% of the vertical midpoint of the face;a plurality of perimeter weight receptacles positioned in at least two regions selected from heel, toe, and rear;interchangeable weight members removably secured in said receptacles by a retention mechanism;wherein placement of the weight members across a plane defined by the hosel axis and target line biases draw or fade, and placement of a weight member rearward increases moment of inertia.

2. The golf club of claim 1, wherein the mass distribution and hosel placement render the club head face-balanced about the shaft axis, reducing face-closure rate variability compared to a heel-shafted driver at matched loft and shaft.

3. The golf club of claim 1, wherein the hosel axis intersects the face within ±5 mm of the geometric face center.

4. The golf club of claim 1, wherein the shaft axis passes within 5 mm of the club head's center of gravity.

5. The golf club of claim 1, wherein the perimeter weight receptacles comprise receptacles at heel, toe, and rear regions that are non-colinear relative to the club head center.

6. The golf club of claim 1, wherein the retention mechanism comprises a non-threaded bayonet, detent, cam, or magnetic latch mechanism.

7. The golf club of claim 1, wherein the retention mechanism comprises threaded engagement of a weight screw with a threaded receptacle.

8. The golf club of claim 1, wherein, for a toe-impact struck 20-25 mm from face center at a swing speed within a defined band, lateral deviation is reduced relative to a heel-shafted driver of equivalent loft and head volume.

9. The golf club of claim 1, wherein, in a rear-max configuration, launch angle increases by approximately 1-2 degrees and backspin increases by approximately 300-500 rpm for swing speeds below 95 mph; and in a forward-max configuration, backspin decreases by approximately 500 rpm for swing speeds above 100 mph.

10. The golf club of claim 1, wherein exactly three non-colinear perimeter weight receptacles are provided at heel, toe, and rear regions.

11. A method of calibrating a golf driver, comprising: providing a golf club as in claim 1; collecting baseline launch-monitor data including side-spin and offline dispersion; installing a heavier weight member on one side of said shaft-axis plane to exaggerate a corrective bias; instructing the golfer to strike shots and recording launch-monitor data; and iteratively repositioning weight members across said plane until offline dispersion is reduced relative to baseline or side-spin magnitude is reduced below a threshold.

12. The method of claim 11, further comprising repositioning at least one weight member along a face-normal axis toward a rear receptacle to increase MOI and launch, or toward a forward receptacle to reduce spin, until the golfer's launch and spin fall within target bands.

13. A fitting kit comprising: a driver club head as in claim 1; a plurality of weight members of at least three different masses; and a tool configured to engage the retention of the weight members; wherein weight members are interchangeably installable in heel, toe, and rear receptacles to adjust center of gravity laterally and vertically.

14. The fitting kit of claim 13, wherein the weight members are non-threaded cartridges retained by a bayonet, detent, cam, or magnetic latch mechanism.

15. The fitting kit of claim 13, wherein the weight members are threaded screws configured to engage mating threads in the receptacles.

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