Golf tee with enhanced aerodynamic drag

Abstract

This invention is a golf tee having an aerodynamic drag portion with a relatively large frontal area and aerodynamic drag coefficient, an intentionally minimized mass, and a subsequent reduction in flight distance upon being struck with a golf club. This reduced flight distance coupled with the relatively large area of the drag portion makes this tee relatively easy to find. It is economically feasible, therefore, to make this tee from a virtually indestructible but relatively more expensive material such as polyurethane. The resulting tee has significantly greater operational life than conventional tees.

Description

BACKGROUND

1. Field of Invention

This invention is a golf tee assembly containing a tee portion which elevates a golf ball and an aerodynamic drag portion to reduce its flight distance after being struck by a golf club. This reduced flight distance along with the relatively large size of the aerodynamic drag portion provides a tee which is relatively easy to find. In a preferred embodiment, the two portions are two distinct members which are adjustably attached. Since the tee is easily found, it is practical to make the tee from a durable but relatively more expensive material, such as polyurethane, providing a tee with an exceptionally long operational life.

2. Description of Prior Art

Common rules of the game of golf allow the use of a tee to elevate a golf ball above the ground on the first stroke of a hole. This makes striking the ball easier, especially with golf clubs with relatively large heads such as a driver or fairway wood. Tees commonly used today are made from wood or plastic, have a pointed end for insertion into the ground and a recessed top to support a golf ball. When the ball is struck with the club, the tee is usually also struck and an initial velocity is imparted to the tee. This velocity, for any particular club impact, is essentially independent of the tee's mass since the tee's mass is considerably smaller than the mass of the club head. An initial kinetic energy is therefore imparted to the tee, the magnitude of this kinetic energy being essentially proportional to the tee's mass. For a given club impact, a conventional tee can travel a relatively large distance in various directions making it difficult to find. Breakage is also common, especially in the case of wooden tees. Conventional tees therefore have a relatively short life due to loss or breakage.

One way to prevent tee loss is to simply tie the tee to the ground. Two U.S. patents, U.S. Pat. No. 6,494,796 to Echaves (2002) and U.S. Pat. No. 5,413,348 to Basso (1995) show two methods of tying a tee to the ground. Present United States Golf Association rules prevent using a tee which can be used to indicate an intended line of play. The tethers shown in these two patents probably violate this rule since the tether could be positioned to indicate an intended line of play.

Several patents for golf tees show the use of a disk-shaped member in their construction but which are not optimally effective in reducing the distance the tee can travel after being struck by a golf club. U.S. Pat. No. 6,475,107 to Sand (2002) shows a tee assembly containing a disk-shaped member, but the purpose of the disk-shaped member is to provide consistent elevation of a golf ball above a teeing surface. The diameter of the disk is shown as having a diameter significantly smaller than the diameter of a golf ball which means it would have limited aerodynamic drag. Also, the two members of the tee assembly as shown are relatively easily separated, and if separated, the disk-shaped member would not reduce the flight distance of the ball-supporting member.

U.S. Pat. No. 5,052,689 to Lettrich (1991) shows another disk-shaped member used to provide consistent ball elevation. Here again, the disk is typically shown as having a diameter considerably smaller than a golf ball, limiting its aerodynamic drag. In addition, the disk and its shank are shown as having a relatively large thickness, thereby resulting in a disk and shank with a relatively large mass. This large mass, combined with the initial velocity imparted to the tee by the club, means the tee assembly will have a relatively large amount of initial kinetic energy and its travel distance will be relatively great.

U.S. Pat. No. 5,242,161 to Wilkirson (1993) also shows a tee assembly which contains a member having a disk-shaped portion but with a diameter greater than the diameter of a golf ball, but here again this member as shown can easily separate from the ball-supporting member. Also, the member containing the disk-shaped portion is drawn as being relatively large in size, with relatively thick members, and therefore would have a relatively large mass and relatively large travel distance.

U.S. Pat. No. 4,998,732 to Gallant (1991) shows a tee assembly containing a disk-shaped member attached to a ball-supporting member. The diameter of the disk portion is shown as being appreciably smaller than a golf ball, and the disk portion is shown as being relatively thick which means relatively large mass, and the travel distance of the tee will be relatively large. In addition, one side of the disk portion is shown as having a tapered shape which would have a relatively low aerodynamic drag coefficient (it would be considered to have a good aerodynamic design), and this shape would further reduce the aerodynamic drag. Therefore, this assembly is also not optimally designed to provide enhanced aerodynamic drag with reduced mass.

OBJECTS AND ADVANTAGES

An object of this invention is a golf tee assembly having an aerodynamic drag portion with an aerodynamic drag surface which reduces the distance the tee travels when struck by a golf club.

A further object of this invention is a golf tee assembly having an aerodynamic drag surface with a shape which increases the aerodynamic drag coefficient of the surface.

A further object of this invention is a golf tee assembly which is relatively easy to find because of its reduced travel distance and a relatively large area of its aerodynamic drag surface.

A further object of this invention is a golf tee assembly which is made from an operationally indestructible material, which along with its being relatively easy to find, results in a tee assembly which can be used many times before breakage or loss.

A further object of this invention is a tee assembly which complies with commonly accepted rules of golf.

Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.

DRAWING FIGURES

FIG. 1 shows a disassembled view of the golf tee of this invention and

FIG. 2 shows in cross-section the tee of this invention placed in the ground with a ball in position to be struck by a golf club.

REFERENCE NUMERALS IN DRAWINGS

• 5 golf tee assembly
• 10 tee portion
• 20 tee tip
• 30 recessed top
• 40 shoulder
• 50 shaft
• 60 aerodynamic drag portion
• 70 drag portion hole
• 80 golf ball
• 90 ground

DESCRIPTION AND OPERATION-FIGS. 1 & 2

FIG. 1 shows a golf tee assembly 5 of this invention which contains a tee portion 10 for elevating a golf ball and an aerodynamic drag portion 60. Tee portion 10 contains a tip 20 for insertion of assembly 5 in the ground, a recessed top 30 for holding a golf ball, a shoulder 40, and a shaft 50 having a diameter smaller than the diameter of shoulder 40 and top 30. Aerodynamic drag portion 60 contains a hole 70, the diameter of hole 70 being preferably slightly less than the diameter of shaft 50 but certainly smaller than the diameter of shoulder 40 and top 30. A preferred shape for the perimeter of drag portion 60 is a circle, making portion 60 a circular disk, thereby preventing portion 60 and therefore assembly 5 from indicating any preferred direction, therefore complying with common rules of golf. Drag portion 60 is normally made of a relatively resilient material, such as polyurethane, so that hole 70 can be stretched over shoulder 40, therefore positioning and captivating drag portion 60 on shaft 50 between shoulder 40 and top 30. Tip 20, shoulder 40, and shaft 50 form a barb, and with hole 70, portion 10 and aerodynamic drag portion 60 cannot separate.

FIG. 2 also shows tee assembly 5 with similar parts as described above but shown in position with tip 20 inserted in ground 90. A golf ball 80 is sitting on recessed top 30 ready to be struck by a golf club (not shown). When using tee assembly 5, the golfer inserts tip 20 into ground 90 to any desired distance to provide a preferred location of ball 80 relative to ground 90. Drag portion 60 is then preferably slid along shaft 50 positioning drag portion 60 against ground 90. Also, drag portion 60 is shown as optimally having a contoured thickness. The larger thickness near hole 70 and at the perimeter of drag portion 60 provides the strength requirements of portion 60, but the reduced thickness in the remaining sections provide an optimally reduced mass. The shape shown also has an enhanced aerodynamic drag coefficient, a term which indicates how “streamlined” an object is. The shape shown has a relatively high aerodynamic drag coefficient, having a shape somewhat like a parachute.

Tee assembly 5 has a reduced chance of being lost because aerodynamic drag portion 60 provides tee assembly 5 with a relatively large aerodynamic drag relative to its mass. The resulting reduced flight distance, along with the relatively large surface area of drag portion 60, makes finding assembly 5 easier than a tee without portion 60. Conventional tees, which have a shape similar to tee portion 10 except they do not have shoulder 40, have relatively good aerodynamic characteristics, looking somewhat like a bullet. Therefore, when struck by a golf club, they can fly a considerable distance, and this, combined with their relatively small size, sometimes makes them hard to find.

The term aerodynamic drag denotes a force exerted on an object as it travels through a medium such as air. The integral of this force over distance traveled is the kinetic energy lost by the object in traveling the distance. The aerodynamic drag of a body is affected by its area and its aerodynamic drag coefficient. A flat circular disk has an aerodynamic drag coefficient of about 1.3; if contoured as shown in FIG. 2, it will increase to 1.5 to 2.0. A bullet by comparison has an aerodynamic drag coefficient of only about 0.3. Therefore, to minimize travel distance, an object should have a relatively large area with a relatively high drag coefficient, and its mass should be low giving it a low kinetic energy for any given initial velocity. An indicator which represents the effectiveness of tee assembly 5 of this patent in limiting travel distance, called a drag indicator, is the product of the maximum frontal area it can present to the approaching air times the drag coefficient of this area divided by the mass. A tee assembly 5 was constructed from polyurethane, tee portion 10 having a total length of about 64 mm (2.5″), drag portion 60 had a diameter of about 42 mm (1.66″) (approximately the diameter of a golf ball), and assembly 5 had a total mass of 4.4 grams. The maximum area of disk 60 is therefore 1385 mmˆ2, and using a drag coefficient of 1.5 for the surface shape shown, the drag indicator for the tee of this invention is 1385 mmˆ2*1.5/4.4 g=472 mmˆ2/gram. By comparison, a conventional wooden tee has a mass of 1.1 grams with a top diameter of 11 mm (0.43″) for an area of 95 mmˆ2, and when flying “like a bullet” with an estimated drag coefficient of 0.3 gives a drag indicator of only 95 mmˆ2*0.3/1.1 g=26 mmˆ2/gram.

Inventor has used conventional tees, and typically these tees are either lost or broken 30% to 50% of the time. In other words, if ten drives were made with these tees, approximately 3 to 5 tees would be lost or broken. A tee was constructed from polyurethane having a design similar to assembly 5, and Inventor has made over 1000 drives with this tee and “it's still going”. A typical flight distance is less than 3 meters, and this small distance, coupled with the relatively large surface area of drag portion 60, enables the tee to be found relatively easily.

Since drag portion 60 in the preferred embodiment has a circular perimeter (it is a round disk), it cannot be used to indicate a preferred line of play and therefore complies with commonly used golf rules.

SUMMARY, RAMIFICATION, AND SCOPE

Accordingly, this invention is a golf tee assembly which has aerodynamic flight characteristics somewhat like a badminton birdie. It has an aerodynamic drag portion which provides the assembly with a relatively large aerodynamic drag compared to its mass. This large aerodynamic drag reduces the tee's flight distance when struck with a golf club, and this reduced flight distance, coupled with the relatively large area of the drag portion, makes it easily found. It is economically justified therefore to make this tee from a relatively more expensive but operationally unbreakable material, such as polyurethane, which coupled with its reduced likelihood of loss, provides a tee which rarely needs replaced.

Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For instance, drag portion 60 can be some other shape than round and it will still reduce flight distance. Portion 60 may contain additional holes or be made from a screen-like material to further reduce its mass. The shape of tee portion 10 can be changed as long as drag portion 60 cannot operationally separate from tee portion 10. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.

Claims

1. A golf tee containing a first portion which supports a golf ball and a second portion which provides an aerodynamic drag,

attachment means whereby said second portion can affect a movement of said first portion when said tee is traveling through the atmosphere,

said second portion containing a surface upon which said atmosphere applies an aerodynamic drag force when said surface travels through said atmosphere,

said surface having a perimeter which encloses a frontal area measured in millimeters squared,

said surface having an aerodynamic drag coefficient,

said tee having a mass measured in grams,

a drag indicator which is said area measured in millimeters squared times said aerodynamic drag coefficient divided by said mass measured in grams,

and wherein said drag indicator is greater than three hundred millimeters squared per gram.

2. The tee of claim 1. wherein said perimeter is a circle.

3. The tee of claim 2. wherein the diameter of said circle is approximately the diameter of a golf ball.

4. The tee of claim 1. wherein said first portion is made from a resilient material.

5. The tee of claim 4. wherein said resilient material is polyurethane.

6. The tee of claim 1. wherein said second portion is made from a resilient material.

7. The tee of claim 6. wherein said resilient material is polyurethane.

8. The tee of claim 1. wherein said surface having a perimeter which encloses a frontal area has an aerodynamic drag coefficient which is greater than the aerodynamic drag coefficient of a flat surface having the same perimeter which encloses the same frontal area.

9. The tee of claim 1. wherein said second portion has a shape similar to a disk with a diameter greater than 20 times its average thickness.

10. The tee of claim 1. wherein said first portion is made from an operationally indestructible material.

11. The tee of claim 10. wherein said material is polyurethane.

12. The tee of claim 1. wherein said second portion is made from an operationally indestructible material.

13. The tee of claim 12. wherein said material is polyurethane.

14. The tee of claim 1. wherein said attachment means is a barb on said first portion and a hole in said second portion.