GB1582872A - Rackets - Google Patents

Description

(54) RACKETS (71) We, COLGATE-PALMOLIVE COMPANY, a Corporation organised under the laws of the State of Delaware, United States of America, of 300 Park Avenue, New York, New York 10022, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be described in and by the following statement: This invention relates to game rackets, particularly tennis rackets.

According to the invention a tennis racket comprises a head frame and a handle portion, the head frame having a maximum width dimension of approximately 9 inches and defining a strung area for hitting a ball, the head frame and handle portion comprising in cross section, which may be generally rectangular, an outer layer of reinforcing fibres dispersed in a matrix of thermosetting resin and an inner core of a rigid foamed material, the racket having an overall length dimension of approximately 29 inches, a balance point at a distance in the range from 121/2 to 131/2 inches from the butt of the handle portion, and an overall strung weight in the range from 121/2 to 14 ounces, and the handle portion comprising a grip and a shaft, the shaft extending from the grip to the head frame, and the grip having a length of approximately 9 inches.

The racket thus has a geometric ratio of approximately 3.2, the geometric ratio being the quotient of the overall length of the racket and the maximum width of the head frame.

The overall length of approximately 29 inches is greater than the overall length of the conventional racket which is approximately 27 inches, but the racket has essentially the same stringed area, balance, overall weight, deflection characteristics and "feel" as the conventional racket. The grip length is longer than conventional, affording a longer playing reach and facilitating two handed strokes. The increased length also provides greater leverage in hitting the ball, i.e. more power for a given stroke.

As used herein in relation to a dimension, "approximately" means the stated dimension plus or minus a minor fraction of an inch. Variations from the stated dimension may depend, for example, on materials, tolerances and finish.

The invention may be performed in various ways, and an embodiments thereof will now be described by way of example, as well as a conventional racket for comparison, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a conventional tennis racket; Figure 2 is a plan view of a tennis racket embodying the invention; and Figure 3 is a cross section of the frame of the racket of Figure 2 taken along the line 3-3 of Figure 2.

Figure 1 shows a conventional tennis racket having an overall strung weight in the range from 121/2 to 14 ounces. The overall length L is conventionally approximately 27 inches. The grip length G is usually approximately 7 inches. The head length at H is typically 113/4 inches and the head width Hw is typically 9 inches. The so-called shaft length, which is the portion of the racket between the grip and head, is indicated at S. The balance point is indicated at B, and in conventional rackets the distance B, of this point from the butt of the handle is usually in the range from 121/2 to 131/2 inches.

Figure 2 shows a tennis racket embodying the invention, having a head frame 11 defining a strung area 14, a handle shaft -12 and a grip 13. The head length Ht and width Hw are substantially unchanged from the conventional racket of Figure 1 so that the racket presents the same striking area as conventional rackets. This is important from the stand-point of economy in manufacture, as well as not requiring a player to adapt himself to a different head size.

The shaft length S is preferably maintained as in conventional rackets but the grip length G1 is increased materially with respect to conventional rackets.

The overall weight is about 12l/2- ounces unstrung.

The grip length G1 is approximately 9 inches and the overall racket length L is approximately 29 inches. Thus the grip of the racket is about 2 inches longer than in a conventional racket, all other dimensions, except overall length, being substantially the same as a conventional racket. The balance point B remains in the shaft, and its distance B, from the butt of the handle portion is in the range from 12l/2 to 13l/2 inches. Thus the overall weight and the distance of the balance point from the butt of the handle are the same as conventional, so that while the racket enables the player to have a wider range of about 4 inches for the same reach, increased leverage and power (up to 10%), better two-handed gripping, and an increased serving angle, the racket feel is the same as conventional.

For the racket a geometric factor is defined for providing improved length characteristics while maintaining the "feel" of a conventionally designed racket. The geometric factor is the quotient of the overall length of the racket (L) and the maximum width of the head frame (H,). For the racket of the present invention the geometric factor is about 3.2.

The stiffness of the racket, measured as head end deflection, is in the range from 1/2 to 5/8 inch, to provide the racket with substantially the same "feel" during normal play as a conventional racket. The end deflection is measured by rigidly supporting the handle of the racket to a point 6t/2 inches forward of the butt and suspending an 81/2 pound weight from the head end of the racket. The deflection is the measured distance the head end is deflected when the weight is applied.

In use the player has the option of adjusting speedily his playing capability by shortening his grip as for quick volleys at the net or lengthening the grip as for service.

Referring now to Figure 3, the head frame cross section of a racket embodying the invention is shown. The frame comprises an outer layer or skin 15 of reinforcing fibres dispersed in a matrix of thermosetting resin, and a core 16. of rigid foamed material. The reinforcing fibres may consist of fibres of glass, carbon, boron, textile materials or metal and may be in the form of.rovings, filaments or woven fabrics which are embedded in a thermosetting synthetic resin, such as an epoxy or polyester resin. The fibres are typically overlaid in layers with the fibres oriented at angles to the fibres in adjacent layers, which results in desired stiffness and torque resistance at any given point.

The strings can be retained in the head frame by a string strip 17 that is typically a plastics material. The string strip extends around the periphery of the head frame and has holes for receiving the strings. Corresponding holes are drilled in the head frame so that the strings can pass across the strung area 14.

A specific example of a racket according to the invention is as follows: L - 29" H1 113/5" S - 8l/2" G, - 9" Hw - 9' B, - 13" The frame is composed of a matrix of polyester resin with graphite fibres obliquely and/or longitudinally dispersed in the matrix. The core 16 is a rigid polyurethane or syntactic foam.

The use of a fibre reinforced plastic matrix outer layer with a rigid foam inner core for the frame material is particularly advantageous since this material permits the maintenance of conventional racket balance, weight and deflection while permitting increased length of the grip relative to a conventional wood or aluminium 27" overall length racket.

WHAT WE CLAIM IS: 1. A tennis racket comprising a head frame and a handle portion, the head frame having å maximum width dimension of approximately 9 inches and defining a strung area for hitting a ball, the head frame and handle portion comprising in cross section an outer layer of reinforcing fibres dispersed in a matrix of thermosetting resin and an inner core of a rigid foamed material. the racket having an overall length dimension of approximately 29 inches, a balance point at a distance in the range from 121/2 to 131/2 inches from the butt of the handle portion. and an overall strung weight in the range from 121/2 to 14 ounces, and the handle portion comprising a grip and a shaft, the shaft extending from the grip to the head frame, and the grip having a length of approximately 9 inches.

2. A tennis racket according to Claim 1 having a stiffness measured as head end deflection in the range from 1/2 to 5/8 inch when an 81/2 pound weight is suspended from the end of the head frame and the handle portion is rigidly supported from the butt to a point 61/2 inches forward of the butt.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. economy in manufacture, as well as not requiring a player to adapt himself to a different head size. The shaft length S is preferably maintained as in conventional rackets but the grip length G1 is increased materially with respect to conventional rackets. The overall weight is about 12l/2- ounces unstrung. The grip length G1 is approximately 9 inches and the overall racket length L is approximately 29 inches. Thus the grip of the racket is about 2 inches longer than in a conventional racket, all other dimensions, except overall length, being substantially the same as a conventional racket. The balance point B remains in the shaft, and its distance B, from the butt of the handle portion is in the range from 12l/2 to 13l/2 inches. Thus the overall weight and the distance of the balance point from the butt of the handle are the same as conventional, so that while the racket enables the player to have a wider range of about 4 inches for the same reach, increased leverage and power (up to 10%), better two-handed gripping, and an increased serving angle, the racket feel is the same as conventional. For the racket a geometric factor is defined for providing improved length characteristics while maintaining the "feel" of a conventionally designed racket. The geometric factor is the quotient of the overall length of the racket (L) and the maximum width of the head frame (H,). For the racket of the present invention the geometric factor is about 3.2. The stiffness of the racket, measured as head end deflection, is in the range from 1/2 to 5/8 inch, to provide the racket with substantially the same "feel" during normal play as a conventional racket. The end deflection is measured by rigidly supporting the handle of the racket to a point 6t/2 inches forward of the butt and suspending an 81/2 pound weight from the head end of the racket. The deflection is the measured distance the head end is deflected when the weight is applied. In use the player has the option of adjusting speedily his playing capability by shortening his grip as for quick volleys at the net or lengthening the grip as for service. Referring now to Figure 3, the head frame cross section of a racket embodying the invention is shown. The frame comprises an outer layer or skin 15 of reinforcing fibres dispersed in a matrix of thermosetting resin, and a core 16. of rigid foamed material. The reinforcing fibres may consist of fibres of glass, carbon, boron, textile materials or metal and may be in the form of.rovings, filaments or woven fabrics which are embedded in a thermosetting synthetic resin, such as an epoxy or polyester resin. The fibres are typically overlaid in layers with the fibres oriented at angles to the fibres in adjacent layers, which results in desired stiffness and torque resistance at any given point. The strings can be retained in the head frame by a string strip 17 that is typically a plastics material. The string strip extends around the periphery of the head frame and has holes for receiving the strings. Corresponding holes are drilled in the head frame so that the strings can pass across the strung area 14. A specific example of a racket according to the invention is as follows: L - 29" H1 113/5" S - 8l/2" G, - 9" Hw - 9' B, - 13" The frame is composed of a matrix of polyester resin with graphite fibres obliquely and/or longitudinally dispersed in the matrix. The core 16 is a rigid polyurethane or syntactic foam. The use of a fibre reinforced plastic matrix outer layer with a rigid foam inner core for the frame material is particularly advantageous since this material permits the maintenance of conventional racket balance, weight and deflection while permitting increased length of the grip relative to a conventional wood or aluminium 27" overall length racket. WHAT WE CLAIM IS:

1. A tennis racket comprising a head frame and a handle portion, the head frame having å maximum width dimension of approximately 9 inches and defining a strung area for hitting a ball, the head frame and handle portion comprising in cross section an outer layer of reinforcing fibres dispersed in a matrix of thermosetting resin and an inner core of a rigid foamed material. the racket having an overall length dimension of approximately 29 inches, a balance point at a distance in the range from 121/2 to 131/2 inches from the butt of the handle portion. and an overall strung weight in the range from 121/2 to 14 ounces, and the handle portion comprising a grip and a shaft, the shaft extending from the grip to the head frame, and the grip having a length of approximately 9 inches.

2. A tennis racket according to Claim 1 having a stiffness measured as head end deflection in the range from 1/2 to 5/8 inch when an 81/2 pound weight is suspended from the end of the head frame and the handle portion is rigidly supported from the butt to a point 61/2 inches forward of the butt.

3. A tennis racket substantially as described with reference to Figures 2 and 3 of the

accompanying drawings.