Line fault detector

• US 4,664,376 A
• Filed: 06/30/1983
• Issued: 05/12/1987
• Est. Priority Date: 12/03/1981
• Status: Expired due to Fees

• Current Assignee: George S. Gray
• Original Assignee: George S. Gray
• Inventors: Gray, George S.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/519,772
• Time in Patent Office: 1,412 Days
• Field of Search: 273/31, 273/374, 273/29 R, 273/50, 340/323 R, 340/551, 340/572, 434/339
• US Class Current: 473/467
• CPC Class Codes: A63B 2071/0611 Automatic tennis linesmen, i.e. in-out detectors
• CPC Class Codes: A63B 2209/08 magnetic
• CPC Class Codes: A63B 43/00 Balls with special arrangements
• CPC Class Codes: A63B 71/0605 Decision makers and devices using detection means facilitating arbitration

Abstract

A plurality of coils (2) are situated beneath a playing surface (4), for example of a tennis court, and extending end to end adjacent a boundary line (5). An oscillator circuit (FIG. 2) associated with each coil produces an electromagnetic field 9 in the coil vicinity. A detector circuit associated with each oscillator issues a detection signal when the field is disturbed by a ball comprising a metal or ferromagnetic material. A processor interrogates the detectors to determine which, if any, have issued a detection signal. Desirably, the ball has a metal or ferromagnetic material internally thereof. More preferably the metal is a foil urged against an interior wall of the ball by a resilient mass or bladder.

Claims

1. Detection apparatus for sensing the proximity of a tennis-type ball to a tennis-type court boundary, the ball including a metallic or ferromagnetic substance, said apparatus comprising:

a plurality of first coils disposed each adjacent another longitudinally along and parallel to a single predetermined line of the boundary,

a plurality of second coils disposed each adjacent another longitudinally along and parallel to the same single predetermined line of the boundary and substantially parallel to said first coils and spaced immediately laterally adjacent thereto by a distance no greater than about 20 cm.,

a plurality of oscillators, one associated with each coil for generating an associated oscillating field in the respective coil vicinity,

a plurality of detectors, one associated with each oscillator and responsive to a disturbance, if any, of the associated oscillating field by the metallic or ferromagnetic material of the ball passing through said field to issue a detection signal,

identifying means for issuing a signal identifying which one, if any, of said detectors has issued a detection signal, said identifying means including means for repeatedly separately scanning said detectors associated with said first and second plurality of coils in a sequence to issue a signal indicative of the location of any detector which has issued a detection signal,

whereby the proximity of the ball to the boundary may be detected.

2. Apparatus according to claim 1 wherein the identification means includes a microprocessor.

3. Apparatus according to claim 1 wherein each coil is elongated and extends in the direction of a portion of said predetermined boundary line.

4. Apparatus according to claim 3 wherein the coil is buried adjacent the boundary.

5. Apparatus according to claim 3 wherein the coil is formed in a tile element forming a portion of the surface of a tennis court.

6. Apparatus according to claim 1 wherein the plurality of first and second coils include elongated coils disposed on opposite sides of the predetermined boundary line.

7. Detection apparatus for sensing the location of a tennis-type ball to individual lines of a tennis-type court boundary, the ball including a metallic or ferromagnetic substance, said apparatus comprising:

a plurality of at least ten coils disposed each adjacent another longitudinally along each of said individual lines of the boundary,

a plurality of oscillators, one associated with each coil for generating an associated oscillating field in the repective coil vicinity,

a plurality of detectors, one associated with each oscillator and responsive to a disturbance, if any, of the associated oscillating field by the metallic or ferromagnetic material of the ball passing through said field to issue a detection signal,

identifying means for issuing a signal identifying which one, if any, of said detectors has issued a detection signal in response to disturbance of its associated oscillating field by the ball passing through said field, said identifying means including means for repeatedly scanning said detectors in a sequence along each of said individual lines to issue a signal indicative of the location of any detector which has issued a detection signal,

whereby the location of the ball to the boundary may be detected as it passes through any one of said oscillating fields.

8. Detection apparatus for a tennis-type game for sensing the location of a tennis-type ball to individual lines of a tennis type court boundary, the ball having a metallic substance in the interior thereof constructed to substantially maintain the normal aerodynamic, resilience and deformability characteristics of the normal tennis-like ball, said apparatus comprising:

a plurality of at least ten coils disposed each adjacent another longitudinally along each of said individual lines of the boundary,

a plurality of oscillators, one associated with each coil for generating an associated oscillating field in the respective coil vicinity,

a plurality of detectors, one associated with each oscillator and responsive to a disturbance, if any, of the associated oscillating field by the metallic or ferromagnetic material of the ball passing through said field to issue a detection signal,

identifying means for issuing a signal identifying which one, if any, of said detectors has issued a detection signal in response to disturbance of its associated oscillating field by the ball passing through said field, said identifying means including means for repeatedly scanning said detectors in a sequence along each of said individual lines to issue a signal indicative of the location of any detector which has issued a detection signal, said scanning being at a speed sufficient to repeat the scanning of any one detector within the time it takes said ball to disturb the oscillating field of the oscillator associated with said one detector by passing through said field during normal speeds associated with said tennis-type game,

whereby the location of the ball to the boundary may be detected as it passes through any one of said oscillating fields.

9. Apparatus according to claim 8 wherein the coils each extend for about 30 cm along each of said individual lines of the boundary.

10. Detection apparatus for a tennis-type game for sensing the location of a tennis-type ball to a tennis-type court boundary, the ball having a metallic substance in the interior thereof constructed to substantially maintain the normal aerodynamic, resilience and deformability characteristics of the normal tennis-like ball, said apparatus comprising:

a plurality of coils disposed each adjacent another longitudinally along the boundary, including;

(a) a first plurality of coils disposed each adjacent another longitudinally along the boundary immediately adjacent one side thereof;

(b) a second plurality of coils disposed each adjacent another longitudinally along the boundary immediately adjacent the other side thereof; and

(c) a third plurality of coils disposed adjacent another longitudinally along the boundary and immediately therebelow;

a plurality of oscillators, one associated with each coil for generating an associated oscillating field in the respective coil vicinity;

a plurality of detectors, one associated with each oscillator and responsive to a disturbance, if any, of the associated oscillating field by the metallic or ferromagnetic material of the ball passing through said field to issue a detection signal;

identifying means for issuing a signal identifying which one, if any of said detectors has issued a detection signal in response to disturbance of its associated oscillating field by the ball passing through said field, said identifying means including means for repeatedly scanning said detectors in a sequence to issue a signal indicative of the location of any detector which has issued a detection signal, said scanning being at a speed sufficient to repeat the scanning of any one detector within the time it takes said ball to disturb the oscillating field of the oscillator associated with said one detector by passing through said field during normal speeds associated with said tennis-type game;

whereby the location of the ball to the boundary may be detected as it passes through any one of said oscillating fields.