System for selective detection and indication of impacts upon a base surface

• US 4,062,008 A
• Filed: 02/09/1976
• Issued: 12/06/1977
• Est. Priority Date: 02/09/1976
• Status: Expired due to Term

• Current Assignee: Nils Jeppson
• Original Assignee: Nils Jeppson
• Inventors: Carlsson, Carl-Eric Waldenburg, Holmstedt, Goran Solve
• Primary Examiner(s): Gill, James J.
• Assistant Examiner(s): Ciarlante, Anthony V.
• Application Number:
  US05/656,684
• Time in Patent Office: 666 Days
• Field of Search: 73/12, 116/114 AH, 273/29 A, 273/184 R, 340/323 R, 340/258 R, 317/249 R, 361/291
• US Class Current: 340/323.00R
• CPC Class Codes: A63B 2071/0611 Automatic tennis linesmen, i.e. in-out detectors
• CPC Class Codes: A63B 71/0605 Decision makers and devices using detection means facilitating arbitration

Abstract

A system is provided for selectively detecting and indicating impacts on a base surface, said system comprising at least one detector unit and at least one indicator unit. Said detector unit comprises one or more capacitors between the plates of which an elastic material is inserted, the distance between said capacitor plates as well as the dynamic spring rate of the elastic material being adjusted to the type of impact to be detected and/or the nature of the base surface, and said detector unit is connected to a voltage source via a resistor having high resistance which is chosen with respect to the speed of the impacts to be detected. Said indicator unit comprises an amplifier connected to the detector unit in such a way that each capacitor in the detector unit actuates the indicator unit, said amplifier amplifying pulses from the detector unit, and a switching means which is connected to the output of the amplifier and which, upon receipt of a pulse from the amplifier, delivers a signal to one or more indicator means during a properly adjusted time.

Claims

1. A system for selectively detecting and indicating momentary impacts on a base surface, said system comprising at least one detector unit and at least one indicator unit, wherein said detector unit comprises one or more capacitors between the plates of which an elastic material is inserted, the distance between said capacitor plates as well as the dynamic spring rate of the elastic material being adjusted to the type of impact to be detected and to the nature of the base surface, said detector unit being connected to a voltage source via a resistor having a sufficiently high resistance such that the charge on said one or more capacitors remains substantially constant during the duration of the impacts to be detected, and said indicator unit comprises an amplifier connected to the detector unit in such a way that each capacitor in the detector unit actuates the indicator unit, said amplifier amplifying pulses from the detector unit, and a switching means which is connected to the output of the amplifier and which, upon receipt of a pulse from the amplifier, delivers a signal to at least one indicator means for a desired time.

2. A system as defined in claim 1, wherein the indicator unit comprises a light diode connected to the switching means.

3. A system as defined in claim 1, designed for selectively detecting and indicating the impacts of a tennis ball on the line marks of a tennis court, said apparatus comprising a plurality of detector units connected each to one indicator unit, wherein the capacitors in each detector unit jointly correspond to at least a portion of a predetermined line mark and have such an area that they, when laid out on the tennis court, cover said portion of said line mark and the detector units, when laid out, cover all the line marks of the tennis court.

4. A system as defined in claim 3, comprising an indicator panel on which the line marks of the tennis court are reproduced by means of light generating units connected to the respective indicator units.