US3920242A

US3920242A - Electrical fencing scoring method and apparatus

Info

Publication number: US3920242A
Application number: US454179A
Authority: US
Inventors: William E Reith; John A Overman
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-25
Filing date: 1974-03-25
Publication date: 1975-11-18
Anticipated expiration: 1992-11-18

Abstract

An apparatus and method for electrically scoring fencing matches is disclosed. The apparatus operates to produce visual and audible scoring signals in response to valid and invalid touch signals produced in response to execution of valid and invalid touches with a fencing weapon. The apparatus can be conditioned to produce valid and invalid scoring signals in foil competition, and valid scoring signals in epee competition in which there are no invalid touches. An indicator control circuit responds in accordance with occurrence of the touch signals to actuate invalid and valid touch indicators. The indicator control circuit includes a first delay circuit to prevent actuation of the invalid touch indicator by spurious signals having less than a predetermined duration, and a second delay circuit to prevent actuation of the valid touch indicator by noise signals having duration of less than a predetermined period. An amplitude sensor in the indicator control circuit prevents actuation of the valid touch indicator by signals of less than a predetermined amplitude. The first delay circuit is convertible from its function of preventing response to spurious invalid touch signals to that of timing 40 millisecond time lapses after valid touches in epee competition during which simultaneous valid touches may be made.

Description

United States Patent [191 Reith et a1.

[ NOV. 18, 1975 ELECTRICAL FENCING SCORING METHOD AND APPARATUS [76] Inventors: William E. Reith, 1677 Eddington Road, Cleveland Heights, Ohio 441 18; John A. Overman, 252 North, Chagrin Falls, Ohio 44022 [22] Filed: Mar. 25, 1 974 [21] Appl. No.1 454,179

[52] US. Cl. 273/1 F [51] Int. Cl. A63B 69/02 [58] Field of Search; 273/1 E, 1 F; 272/57 C [56] References Cited FOREIGN PATENTS OR APPLICATIONS 127,932 8/1960 U.S.S.R. 273/1 F 1,162,554 9/1958 France 272/57 C 81.004 6/1963 France v 273/1 F 1,293,068 4/1962 France 273/1 F 1,148,004 12/1957 France 273/1 F Primary Examiner-Paul E. Shapiro Attorney, Agent, or FirmWatts, l-loffmann, Fisher & Heinke Co.

[57] ABSTRACT An apparatus and method for electrically scoring fencing matches is disclosed. The apparatus operates to produce visual and audible scoring signals in response to valid and invalid touch signals produced in response to execution of valid and invalid touches with a fencing weapon. The apparatus can be conditioned to produce valid and invalid scoring signals in foil competition, and valid scoring signals in epee competition in which there are no invalid touches. An indicator control circuit responds in accordance with occurrence of the touch signals to actuate invalid and valid touch indicators. The indicator control circuit includes a first delay circuit to prevent actuation of the invalid touch indicator by spurious signals having less than a predetermined duration, and a second delay circuit to prevent actuation of the valid touch indicator by noise signals having duration of less than a predetermined period. An amplitude sensor in the indicator control circuit prevents actuation of the valid touch indicator by signals of less than a predetermined amplitude. The first delay circuit is convertible from its function of preventing response to spurious invalid touch signals to that of timing 40 millisecond time lapses after valid touches in epee competition during which simultaneous valid touches may be made.

Sheet 2 of 3 U8. Patent Nov. 18, 1975 ELECTRICAL FENCING SCORING METHOD AND APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to apparatus and method for electrically scoring fencing matches.

The sport of fencing is the modern analogy to the ancient martial art of dueling. As presently practiced, fencers wearing protective garb contest with lightweight weapons, each attempting to score points against the other by touching the other with his weapon. The fencers tread on a mat, called a piste,

which defines the permitted boundary for the contest.

Two of the weapons used in fencing are the foil and the epee. In foil competition, one fencer may score points against his opponent only be touching him with the tip of his weapon in a target region generally defined by the upper torso. Such touches are known as valid touches. No point may be awarded either fencer for touching his opponent with the point of the foil other than on the permitted target. In epee competition, the valid target is the entire body, and a fencer scores points by touching his opponent anywhere with the tip of theepee.

The fencer first accumulating five valid touches against his opponent is declared the winner of the match.

The oldest method of scoring fencing matches is by visual observation by officials, variously referred to as presidents, judges and directors.

Modern fencing weapons are so light that skilled fencers can manipulate them with extreme speed in flurries of action. This speed renders it difficult to determine when touches are scored. Even where several officials are employed to judge a match, visual identification of scoring maneuvers is difficult. Disagreement between officials often occurs, due to the inconsistency in the quality of perspective enjoyed by the various officials. Moreover, judgmment by visual observation is a subjective criterion, and the acuity of vision may vary among officials, and even in the same official.

To obviate these problems, resort has been made to electrical scoring apparatus having touch indicators. Such apparatus employs touch sensing assemblies attached to the weapon tips, which produce valid and invalid touch signals in response to which the apparatus actuates the indicators.

Foil Scoring A valid touch signal in foul includes the breaking of a first circuit and completing a second. A foil has a movable contact on its tip, which is depressed whenever the tip touches an object, breaking the first electrical circuit.

Each contestant wears a vest-like garment which covers the valid target portion of his body. The vest has a conductive surface, and is connected in a second circuit between the electrical scoring apparatus and the opponents foil. The movable contact on each foil is itself conductive. When the movable contact of one fencers foil touches the opponents conductive vest, the second electrical circuit is completed. and the first circuit is broken, producing a valid touch signal.

An invalid touch in foil is indicated merely by the breaking of the first circuit, since in an invalid touch, the foil fails to contact the opponents vest.

Epee Scoring A touch signal in epee constitutes simply the making of one circuit. The movable contact in the epee touch sensor assembly completes the circuit on depression in the course of a touch.

Errant touches on the piste or on the opponent's weapon body are not scored. Accordingly, if a fencers epee tip touches the piste, or his opponentweapon, the electrical scoring apparatus disables the scoring indicators, preventing the registration of a touch in response to such errant touches.

The movable contact on the epee tip is condutive as in the case of the foil. It is connected to a portion of the electrical scoring apparatus which, if grounded, prevents actuation of the valid touch indicators. The piste is grounded, as is the body of each weapon, so that errant touches on the weapon body or the piste are not counted as scores.

2. Description of the Prior Art In electric scoring systems for fencing, lamps are commonly used as indicators of the execution of valid and invalid (off target) touches represented by the valid and invalid touch signals. Generally, a while lamp indicates an off target or invalid touch, and a colored lamp indicates a valid touch. One set of white and colored lamps is connected to the scoring apparatus corresponding to each fencer. When a touch is made, the appropriate color lamp is actuated which corresponds to the touched fencer.

When any touch is made, and any scoring lamp is actuated, the electrical scoring apparatus operates to stop the action by preventing acutation of any further lamps after the lapse of a predetermined time following the first actuation of a lamp. Moreover, the actuation of any lamp indicative of a valid touch immediately prevents the actuation of the invalid touch indicating lamp in the same set of lamps.

Upon the actuation of any indicator lamp, the electrical scoring equipment commonly provides for the actuation of a bell, buzzer or other audio indicator device for a predetermined period afterthe actuation of the lamp A reset circuit is commonly provided so that the match officials can deactuate all the lamps and reset the apparatus after any touch has been noted, and it is desired to resume action.

In epee competition, if each fencer touches the other substantially simultaneously, i.e., within I/25th of a second (40 milliseconds) a touch is scored against each fencer. Accordingly, modern electric scoring equipment provides that when such substantially simultaneous touches occur as represented by the occurrence of first and second valid touch signals, a first valid touch indicator lamp is lighted in response to the first signal, and a second valid touch indicator is lighted in response to the second signal. Since there are no off target body touches in epee, the white, or invalid touch indicator lamps, are not used. Upon the expiration of l/25th second following an epee touch, no further valid touch indicator lamps may be lighted.

While modern electrical scoring equipment for fencing matches has improved substantially the ease and accuracy of scoring, the performance and accuracy of such systems is sometimes adversely affected by extraneous factors. In the course of a fencing match, the

weapons are moved about rapidly, and the fencers clash them together frequently in countering opponents attempted touches. These conditions sometimes cause momentary depression of themovable contacts on the touch sensor assemblies without there being a touch. Generally such depressions are brief, and the signals they produce of smaller amplitude than in the case of actual touches. Such spruious signals, however, are prone to cause indication of touches when in fact no touch has taken place.

In practically any electrical circuitry such as used in electric scoring equipment for fencing matches, noise signals from various sources are transmitted about the circuitry. Such noise signals can result from RF energy in the region of the circuitry, unwanted mutual inductive or electrical couplings among the various components of the circuitry, or ambient electromagnetic energy amanating from the power source. Such noise signals likewise sometimes actuate a touch indicator, in instances in which not touch in fact has occurred.

Early electrical scoring equipment has not been inordinately sensitive to such spurious signals and noise. This earlier equipment was generally made from vacuum tube circuits and mechanical magnetic relays. The mechanical inertia and large inductance of such relay equipment was sufficiently great that it was not generally responsive to the brief duration or low amplitude signals which characterize most noise and spuriour signals.

More recently, however, circuits for scoring fencing matches have utilized solid state components with attendant advantages of light weight, compactness and low power requirement. Due to the absence of mechanical inertia and large coil inductances in the solid state equipment, however, these newer circuits are much more sensitive to brief and low amplitude signals than the previous relay circuits.

It is desirable in electric scoring equipment for fencing that the circuitry be sufficiently flexible in its operation to accommodate scoring for both foil and epee. Epee competition, with its requirement for scoring of simultaneous touches occurring within 1/25th of a second, commonly requires the provision of a separate timing circuit to enable lockout of the valid touch indicators following the lapse of l/25th of a second after the actuation of the first actuated valid touch indicator lamp. Such separate circuits add to the cost and complexity of the apparatus.

Present electric fencing scoring equipment provides that all the indicator lamps be reset to the actuated state upon the actuation of a manual reset circuit. This requires repeated attention of an official, which may be distracting and otherwise inconvenient.

SUMMARY OF THE INVENTION This invention provides a method and apparatus for improved electric scoring of fencing matches. The invention includes method and apparatus for identifying noise and other spurious signals and preventing actuation of touch indicators in response to such signals. The invention eliminates the need for a separate delay circuit for indicating simultaneous touches in epee competition by employing portions of the circuitry in dual function.

The invention employs at least a valid and an invalid touch indicator. An indicator control circuit actuates the indicators to register touches, which are represented by the occurrence of valid and invalid touch signals. The touch signals are produced by touch sending assemblies on the fencing weapons.

According to one feature ofa preferred embodiment,

the indicator control circuit includes a first delay cir-. cuit connected to the invalid touch indicator. The first I delay circuit provides for actuation of the invalid touch indicator by only those invalid touch signals having at least a predetermined duration. This prevents actuation of the invalid touch indicator by momentary operations of the touch sensing assemblies due to weapon motion I and clashing.

A preferred feature of such a first delay circuit provides that an invalid touch signal must be at least eight milliseconds in duration to cause actuation of the in-.

valid touch indicator.

According to a feature of another preferred embodiment, a second delay circuit is connected to the valid touch indicator to prevent its actuation in response to noise signals having a duration of less than a predetermined time period. Such preferred embodiment additionally includes an amplitude sensor connected to the valid touch indicator to prevent its actuation by signals I tion. Circuitry is provided to impress an input to the.

first delay in response to selected valid touch signals and to redirect the output of the first delay circuit from the invalid touch indicator to disable a second means for actuating the second valid touch indicator in.re-

sponse to second valid touch signals, should they occur. Converting circuitry is also provided for changing the time constant of the first delay circuit to disable the second means 1/25th of a second after the'first valid touch is indicated. g

Other features and advantages of this invention will become apparent from the following drawings .anddetailed description of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective viow of a fencingmatch scored by the apparatus of this invention;

FIG. 2 is a simplified block diagram of electrical scoring apparatus embodying this invention;

FIG. 3 is a schematic diagram of an electrical appara tus embodying this invention;

FIG. 4 is an elevational view of a touch sensing assembly for use on the tip of a foil, showing parts of the touch sensing assembly in cross-section;

FIG. 5 is an elevational view of a touch sensing assembly for use on an epee, showing portionsof the I touch sensing in cross-section.

DESCRIPTION OF THE PREFERRED EMBODIMENT An apparatus 10 for scoring fencing matches is shown in FIG. 1. FIG. 1 depicts the apparatus in use in I a match between the fencers X and Y, officiated by a director D. The fencers hold the

weapons

12 and 14 and each attempts to score points by touching hislopponent with his weapon tip. a

The apparatus indicates touches made by the fenccrs with the tips of their weapons in the course of the match. The apparatus 10 indicates both valid and invalid touches, in foil and epee competition. by actuating the appropriate one or more of the indicators Wx, Cx, Cy and Wy.

The apparatus 10 scores touches in response to the occurrence of touch signals. The touch signals are pro duced by the

touch sensor assemblies

16 and 20 mounted on the tips of the

weapons

12 and 14, respectively, in cooperation with two similar conductive surfaced

vests

21 and 22, worn respectively by the fencers X and Y.

The touch signals are directed to the apparatus 10 by way of the

electrical cables

24 and 26 which are connected to the vests and touch sensor assemblies of the repective fencers. The cables are respectively connected to the

reels

28 and 30, which feed out cable resiliently in response to moderate tension to accommodate the fencers movement without tangling the cables.

The apparatus 10 is adapted for scoring both foil and epee competition. In foil competition, two kinds of touch signals can be produced. A valid touch signal occurs when one fencer touches the other on the vest with the tip of his weapon. An invalid touch signal occurs when one fencer touches the other with the tip of his weapon on a part of his opponents body other than that covered by the vest.

In epee competition, on vests are worn, and only valid touch signals are produced. These are produced by the touch sensor assemblies adapted for epee.

The apparatus 10 indicates touches by actuating the indicators Wx, Cx, Wy and Cy, as shown in FIG. 1. Actuation of either of the indicators Wx and Cx indicates a touch by the fencer Y against the fencer X, while actuation of the indicators Cy and Wy indicate a touch by the fencer X against the fencer Y. Preferably the indicators are lamps, with the indicators Wx and Wy being white lamps, the lighting of which indicates invalid touches, and the indicators Cx and Cy being colored lamps the lighting of which indicates valid touches.

FIG. 2 shows a simplified block diagram of the apparatus 10. The apparatus 10 includes the indicator control circuit 36 connected to actuate the touch indicators Wx and Cx in response to touch signals from the touch sensor assembly 20, and the indicator control circuit 40 connected to actuate the touch indicators Cy and Wy in response to touch signals from the touch sensor assembly 16. A power source 42 supplies power for operating the

indicator control circuits

36 and 40 and associated components of the apparatus 10.

The indicator control circuit 36 actuates the indicator Wx in response to the receipt of an invalid touch signal from the touch sensor assembly 20, and is responsive to the receipt of a valid touch signal from the touch sensor assembly 20 to actuate the indicator Cx. Similarly, the indicator control circuit 40 responds to invalid touch signals from the touch sensor assembly 16 to actuate the indicator Wy and to valid touch signals to actuate the indicator Cy.

The

indicator control circuits

36 and 40 are preferably identical in construction, and only the operation of the indicator control circuit 36 is further discussed in detail, the operation of the indicator control circuit 40 being analogous with respect to the touch indicators Cy and Wy.

The indicator control circuit 36, in response to actuation of the valid touch indicator Cx. substantially instantancously locks out and prevents actuation of the invalid touch indicator Wx.

The indicator control circuit 36 is prevented from actuating the indicator Wx in response to invalid touch signals having less than a predetermined duration. This feature prevents spurious signals of brief duration not actually representing invalid touches from actuating the indicator Wx. The indicator control circuit 36, moreover, actuates the valid touch indicator Cx only in response to valid touch signals having a duration greater than a predetermined time period. This feature prevents actuation of the indicator Cx by noise signals having brief duration which may arise in the circuitry of the apparatus 10.

The indicator control circuit 36 is profoundly adjustable to lock out the valid touch indicator Cy in response to the lapse of 40 milliseconds following actuation of the valid touch indicator Cx. Preferably this adjustment of the indicator control circuit 36 is selectively performed in instances in which the apparatus 10 is used to score epee matches, to allow for determination of simultaneous touches.

The

indicator control circuits

36 and 40 are each connected to a stop action circuit 44. The stop action circuit is connected to a comprehensive indicator lockout 46, an audio signal generator 50, and a power control circuit 52. The comprehensive indicator lockout 46 is connected to each of the

indicator control circuits

36 and 40.

Upon the actuation of any of the indicators Wx, Cx, Cy and Wy, the stop action circuit 44 produces a stop action signal which actuates the audio signal generator 50 to produce an audio signal indicating that an indicator has been actuated and a touch has occurred. The stop action circuit 44, after a predetermined time has elapsed following the actuation of any of the indicators, directs a signal to the comprehensive indicator lockout 46 which in turn operates on the indicator control circuits to prevent the further actuation of any indicators. During the time between the first actuation of an indicator and the time at which the predetermined time period lapses, additional indicators may be actuated.

At the time that the comprehensive indicator lockout 46 operates to prevent further indicator actuation, the stop action circuit 44 deactuates the audio signal generator 50 to cease the audio signal.

Upon the actuation of any indicator, the stop action circuit 44 also directs the stop action signal to the power control circuit 52. Upon the expiration of a predetermined time following receipt of the stop action signal, the power control circuit 52 cuts off the power directed to the

indicator control circuits

36 and 40, and thereby causes the deactuation of all the indicators which have been actuated, resulting in a resetting of the apparatus 10 in preparation for resumed action in a fencing match.

FIG. 3 is a schematic diagram of the apparatus 10 embodying this invention.

The power source 42,-provides power to the

indicator control circuits

36 and 40, and to the other components of the apparatus 10. The power source 42 is indicated by the box formed of dotted lines in FIG. 3 and includes a plug 60 of conventional design for connecting to a volt 60 Hz. supply line, the power being transmitted by way of the leads 62 and 64 to a transformer 66. The transformer 66 reduces the voltage by a factor of 10, such that 12 volt 60 Hz. A.C. appears at the outputs 70 and 72 of the transformer 66. This 12 volt A.C. power supply signal is converted to D.C. by a full wave rectifier which includes

diodes

74, 76, 80 and 82. Operation of the power source 42 establishes a 12 volt D.C. signal appearing between the high voltage lead 84 and the low voltage lead 86.

The apparatus is designed for adaptation to battery power as well. The components of the apparatus 10 are all designed to operate satisfactorily when fed from a 12 volt D.C. source, a readily available type of battery power.

It can be seen from FIG. 3 that power is fed.to the components of the indicator control circuit 36, indicated in FIG. 3 by the dotted box bearing the same reference numeral, and to the indicator control circuit 40, indicated by the dotted box in FIG. 3 designated by reference numeral 40. Ppwer is also applied to the touch indicators Wx, Cx, Cy and Wy between the high voltage lead 84 and the low voltage lead 86.

The invalid and valid touch signals are input to the

indicator control circuits

36 and 40 by way of terminals A, B, C, and A, B', and C, respectively, and represent the occurrence of valid and invalid touches. In the absence of a touch, the teminal pairs B-C and B-C are each conductively coupled, while the terminal pairs A-B and A-B are open circuits.

With respect to the indicator control circuit 36, a

. valid touch signal in foil includes breaking the circuit between the terminals B-C and completing the circuit between the terminals B-A'. An invalid touch signal in foil is represented by breaking of a circuit between the terminals B-C. In epee, only valid touch signals are used and these constitute breaking the circuit between the terminals B-C and completing the circuit between the terminals B-A.

The apparatus 10 is convertible for scoring either foil or epee matches. This conversion is accomplished in the preferred embodiment by, for example in the indicator control-circuit 36, changing the position of the

switches

90, 92 and 94. As illustrated in FIG. 3, the

switches

90, 92 and 94 are disposed in the appropriate positions indicated by solid lines for scoring foil matches. The structure and operation of the apparatus 10 in the scoring of foil matches will be'discussed first.

The

indicator control circuits

36 and 40 are preferably identical in construction. Accordingly, only the operation of the indicator control circuit 36 will be discussed in detail, the operation of the indicator control circuit 40 being analogous to that of the indicator control 36. The components of the indicator control circuit 40 are indicated in FIG. 3 by primed reference numerals which correspond to the reference numerals of the elements of the indicator control circuit 36.

The indicator Wx is actuated by the indicator control circuit in response to aninvalid touch signal. The actuation of the invalid touch indicator Wx is accomplihed by applying a positive voltage to the gate of the SCR 100 (see FIG. 3) which causes the SCR 100 to assume a conductive condition, allowing current to flow from the high voltage lead 84 through the indicatorWx, the switch 90, and the SCR 100, to the low voltage lead 86.

The SCR 100 is caused to assume a conductive state in response to an output of a first delay circuit including a resistor 102, a resistor 104a, a unijunction transistor 104, a capacitor 106 and a resistor 110. The unistate, there being a relatively low voltage at its emitter,

When a positive voltage is applied to the right-hand terminal of the resistor 110, the voltage on the emitter of the unijunction transformer 104 begins to rise at a rate which is a function of the time constant of the RC series circuit represented by the resistor 110 and the capacitor 106.

When the voltage on the emitter of the unijunction transformer 104 .becomes sufficiently high, the unijunction transistor 104 begins to conduct, and the voltage at the upper terminal of the resistor 102 rises. This im-. parts a positive voltage over lead 112 to the gate of the SCR 100, causing the SCR to fire and the indicator WX to be actuated. l

The values of the resistor and the capacitor 10 of the first delay circuit are preferably chosen such that the unijunction transformer 104 will fire approximately 8 milliseconds after the application ofa positive voltage to the right-hand terminal of the resistor 110.

As stated above, the terminals B and C are normally connected in the absence of a touch. An invalid touch signal is represented by the breaking of the circuit be-,

tween the terminals B andC. Upon the breaking of the I circuit between the terminals B and C, the potential at the right-hand terminal of the switch 92 rises, the. potential at that terminal being previously low because of the voltage drop across a resistor 114 connected between the high voltage lead 84 and the terminal B. This breaking of the circuit between the terminals B and C furnishes a positive pulse to the right-hand terminal of the resistor 110, which actuates the first delay circuit. Upon the expiration of approximately 8 milliseconds following the breaking of the circuit between the terminals B and C, the SCR 100 is fired, actuating the invali touch indicator Wx.

This feature assures that the actuation of the invalid touch indicator Wx will not take place in response to invalid touch signals having a duration of less than ap- I proximately 8 milliseconds. The advantage of this is that spurious invalid tough signals of briefer duration, generated by motion and clashing of the weapons, but not representing actual invalid touches, will not cause the invalid touch indicator Wx to indicate an invalid touch.

The valid touch indicator lamp Cx associated with the indicator control circuit 36 is actuated in response to a valid touch signal by the application of a positive voltage to the gate of the SCR 120, in FIG. 3. Such a pulse is derived by the application of a positive voltage to the left-hand terminal of the resistor 124. A second delay circuit including the resistor 124. the capacitor 122, and the resistor 126, is connected to the gate terminal of the SCR 120. The positive voltage on the gate of the SCR is obtained by the application ofa positive voltage to the left-hand terminal of the resistor 124. When such apulse is applied, the SCR 120 is fired after the lapse of a predetermined time period, the magnitude of the predetermined period being' a function of the time constant established by the values of the

resistors

124 and 126, and the capacitor 122, which comprises a second delay circuit.

The positive voltage applied to the left-hand terminal of the resistor 124 is derived from a positive voltage appearing at the right-hand terminal of the switch 94. An amplitude sensor comprising a breakdown diode is interposed between the right-hand terminal of the switch 94 and the resistor 124. Unless the voltage appearing at the right-hand terminal of the switch 94 is above a predetermined minimum, no voltage will be transmitted to the delay circuit and the SCR 120 will not fire.

The voltage pulse appearing at the switch 94 is directed there over the lead 132 extending to the terminal A of the indicator control circuit 40. The voltage pulse is impressed on the lead 132 in response to the occurrence of a valid touch signal.

A valid touch signal is represented by the completing ofa circuit between the terminal B and the terminal A, and by the breaking of the circuit between the terminals B and C. The circuit between the terminals B and A is completed slightly previous to the breaking of the circuit between B and C.

When the circuit between the terminals B and C is broken, the potential of terminal B rises, as in the case of actuation of the invalid touch indicator Wx, discussed above. Because the terminal B is connected to the terminal A, a positive voltage is impressed upon the lead 132, passing through the switch 94 to the breakdown diode 130. If the voltage impressed on the lead 132 is greater than the predetermined minimum breakdown voltage of the breakdown diode 130, a positive voltage will appear at the left-hand terminal of the resistor 124, and actuate the second delay circuit, to fire the SCR 120 a short time after the initiation of the positive signal to the resistor 124.

The presence of the breakdown diode 130 assures that noise signals having small amplitude will not trigger the valid touch indicator Cx. The second delay circuit further assures that noise signals, which are characteristically brief, will likewise not actuate the valid touch indicator Cx.

Another function of the second delay curcuit is to enable the actuation of the valid touch indicator Cx substantially simultaneously, or slightly after, the breaking of the circuit between the terminals B-C. Since the breaking of the circuit between the terminals B-C occurs slightly after the completion of the circuit between the terminals B-A' it is desirable to delay the actuation of the valid touch indicator Cx until the voltage at the terminal B has had an opportunity to build up, to a level greater than the minimum breakdown voltage of the breakdown diode 130.

The actuation of the valid touch indicator Cx prevents the subsequent actuation of the invalid touch indicator Wx, by means of a lockout circuit including the lead 142 and the diode 140. Before the actuation of the valid touch indicator Cx, the terminal 136 is a relatively high potential. Upon actuation of the valid touch indicator Cx, the potential at the terminal 136 drops to a relatively low level, approximately that of the low voltage lead 86. This causes the grounding of the terminal B to the low voltage lead 86 through the diode 140, the lead 142 and the SCR 120. When the terminal B is so grounded, the potential of that terminal cannot rise, and therefore it is not possible subsequently to apply a positive voltage pulse to fire the SCR 100 to actuate the invalid touch indicator Wx.

A stop action circuit is provided in the apparatus 10 to signal when a touch is made and to limit further activity of the apparatus after the first touch occurs. The stop action circuit includes a timer generally indicated by the dotted box 44a in FIG. 3, and a timer actuation circuit. The timer actuation circuit incudes a lead 150 extending from the bottom terminal of the indicator Wx to a bus 153 and having interposed therein a diode 152. The timer actuation circuit further includes a lead 154 having a diode 156 and extending between the lower terminal of the touch indicator Cx to the bus 153.

The timer actuation circuit and the timer 44a operate conjunctively to prohibit the actuation of any further touch indicators at aa time following the first actuation of a touch indicator. This function is performed by a comprehensive light lockout circuit which includes an SCR 160, a lead 162 containing a diode 164, and a lead 166 having interposed therein a diode 170.

The comprehensive light lockout circuit operates in response to the application of a positive pulse to the gate of the SCR 160, normally nonconductive, which renders the SCR 160 in a conductive state. When the SCR 160 becomes conductive, the lead 162 is effectively grounded to the low voltage lead 86. This grounding in turn operates by way of the lead 166 and diode 170 to ground the terminal B of the indicator control circuit 36 and by the lead 162 andthe diode 164 to ground the terminal B of the indicator control circuit 40. The grounding of the terminals B and B render it impossible for a positive tending pulse applied to either of these terminals to raise their potential appreciably, and thus prevents the actuation of any further touch indicators. i

The timer 44a, in response to a low voltage stop action signal, generates and applies to the gate of the SCR 160 a positive pulse at a given time following the receipt of the stop action signal. The timer 44a includes a pnp transistor 172, a resistor 174, a capacitor 176, and resistors and 182 having interposed between them a unijunction transistor 184. The emitter of the transistor 172 is provided with power from the high voltage lead 84.

the transistor 172 is normally in a nonconductive state, and is rendered conductive by the application of the low voltage stop action signal at its base. Upon the application of the low voltage, the transistor 172 conducts, and the voltage at the upper terminal of the capacitor 176 begins to rise at a rate which is a function of the time constant established by the values of the resistor 174 and the capacitor 176. When the voltage at the upper terminal of the capacitor 176 has reached a sufficient value, the unijunction 184 is fired, causing the base 2 terminal of the unijunction 184 to go from a potential substantially equal to that of the low voltage lead 86 to a higher potential which is a function of the ratio of the

resisitors

180 and 182. The ratio of these resistances is appropriately selected such that when the unijunction 184 fires, a positive pulse of sufficient magnitude will be applied to the gate of the SCR 160 to fire that SCR, which in turn causes the grounding of the lead 162 and of the terminals B and B'.

preferably, the values of the resistor 174 and capacitor 176 are chosen such that the SCR 160 is fired by the timer 44a at a time approximately two seconds after the application of the stop action signal to the base of the transistor 172.

The stop action signal is a lowering at the potential applied to the base of the transistor 172 by way of the bus 153. When none of the touch indicators is actuated, the lower terminal of each is at a relatively high potential, which maintains the bus 153 at a correspondingly high potential. When any one or more of the touch indicators is actuated, the potential at the lower terminal of each actuated indicators drops to essentially that of the low voltage lead 86, and this lowering of potential is transmitted to the bus 153. This lowering of potential represents the stop action signal which, when applied to the base of the transistor 172, renders that transistor conductive, actuating the timer 44a which, after a two second interval following the occurrence of the stop action signal, grounds out the terminals B and B of the indicator control circuits, preventing any further actuation of the touch indicators.

The occurrence of the stop action signal also actuates the audio signal generator 50 to produce an audio sig-' nal indicating that a touch has occurred. The audio signal generator includes an audio oscillator of known

design comprising transistors

190 and 192, a diode 194, and associated resistive and capacitive circuit elements illustrated in FIG. 3. The audio signal generator also includes an audio amplifier generally indicated at 196 in FIG. 3, having its input connected to the audio oscillator and a loudspeaker 198 connected to the output of the audio amplifier.

The operability of the audio oscillator and the audio amplifier is determined by the potential condition of the bus 153, which is in turn altered by the occurrence of the stop action signal. When the bus 153 is at a relatively high potential, its potential is substantially equal to that of the high voltage lead 84 which renders the audio signal generator inoperative due to an insubstantial voltage drop across it. It is only when the potential of the bus 153 is maintained at a relatively low level that power can flow through the audio oscillator and audio amplifier in order to actuate the loudspeaker to emit the audio signal for indication of a touch. As discussed above. the actuation of any of the touch indicators causes the potential of the bus 153 to drop to a relatively low level, and therefore the occurrence of the stop action signal immediately actuates the audio signal generator 50 to produce the audio signal.

The cessation of the audio signal occurs in response to the firing of the SCR 160 by the timer 44a after the expiration of the two second period following the occurrence of the stop action signal. When the SCR 160 is fired, the line 162 is effectively grounded through the low voltage lead 86. The line 162 is connected to the audio oscillator by a lead 200. The lead- 200 is thereby grounded by the firing of the SCR 160, which results in the substantially immediate grounding out of the audio oscillator. This renders the oscillator inoperative and causes the audio signal to stop.

The power control circuit 52 is triggered by the occurrence of the stop action signal to cause the deactuation of all actuated touch indicators after the lapse of a predetermined time interval following the occurrence of the stop action signal. The deactuation of the actuated touch indicators is accomplished by momentarily opening a relay 202 interposed in the low voltage lead 86.

The relay 202 is series connected to a line 204 and to a switch 230 and an SCR 206. The opening of the relay 202 interrupts the circuit of the apparatus by opening the low voltage load 86. This causes the low voltage line to assume a voltage which is substantially equal to that of the high voltage line 84. This condition results in the absence of any substantial potential across the components of the apparatus 10, and results in the resetting of the components to conditions such 12 as prevailed before the actuation of any of the indicators.

The relay 202 is normally biased in a closed position, and is opened by the flow of current through the line.

204, which is supplied with a relatively high voltage by the high voltage line 84. Current is permitted to flow through the line 204 by the application of a positive voltage to the gate of the SCR 206. The positive pulse to the gate of the SCR 206 is supplied by a timing cir cuit which includes a variable resistor 210, a resistor 212, and a capacitor 214, connected in parallel with voltage dividing resistors 216 and 220 and separated by a unijunction transistor 222. The positive pulse to the gate of the SCR 206 is provided by firing the unijunction transistor 222. which results in a positive voltage stop action signal, andthc grounding of the bus 153 to I the low voltage lead 86, the timer becomes operative by virtue of current flowing through it between the lead 204 and the bus 153. The emitter voltage of the uni- T junction transistor 222 rises in response to the grounding of the bus 153 at a rate which is a function of the values of the combined resistances of the variable resistor 210 and the resistor 212, and the capacitance 214. When the emitter voltage of the unijunction transistor 222 has risen sufficiently, the unijunction fires, and a positive voltage appears at the lead 224, firing the SCR,

206, causing current to flow through the relay 202, and i through the SCR 206 by way of the switch 230p A series connected capacitor 232 and a resistor 234 are coonnected in parrallel around the relay 202 and the switch 230 in order to provide a means for energy storage which serves to latch the relay 202 in an open position sufficiently long to effect deactuation of the actuated indicators. Without this feature, the relay 202 would be subject to chatter. I

Preferably, the variable resistor 210, the resistor 212, and the capacitor 214 are selected such that the relay 202 is opened and the indicators deactuated after the I lapse of a period variable from two to seven seconds following the occurrence of the stop action signal, de-' pending on the value setting of the variableresistor 210.

Provision is also made for control of the resetting function by manual means, independently of the timer,

if desired. This is provided by a lead 240 extending from the lower terminal of the relay 202 to the low voltage lead 86, having interposed therein a manual reset switch 242. For such manually controlled resetting, the contact of the switch 230 is moved from the .auto to the manual" position, as shown in FIG. 3. This places the relay 202 under sole control of the manual reset switch 242. When the manual reset switch 242, normally opened, is depressed, the relay 202, normally closed, is opened for as long as the reset switch 242 is depressed. In this way manual resetting of the appara: tus 10 may be accomplished. t

The discussion of the apparatus 10 has thus far been concerned with its operation in the configuration for scoring foil competition. The following discussion relates to adjustment and operation of the apparatus for scoring epee competition.

In epee competition the apparatus 10 actuates the valid touch indicators Cx and Cy in response to the occurrence of valid touch signals. The invalid touch indicators Wx and Wy are not used in epee competition.

Preparatory to utilizing the present apparatus for epee scoring, each of the

switches

90, 92 and 94 in the indicator control circuit 36 are adjusted to the positions shown by the dotted lines in FIG. 3. I

The actuation of a valid touch indicator Cx in epee competition, as in foil competition, is accomplished by applying a positive voltage to the gate of the SCR 120.

This positive voltage is applied by way of the left-handterminal of the switch 94, as opposed to the right-hand terminal of the switch in foil scoring. This requires that the switch'94 be moved to its left-hand position for epee competition, as shown by the dotted line in FIG. 3.

The positive voltage pulse at the left-hand terminal of the switch 94 is provided in response to the occurrence of a valid touch signal at the terminals A, B, C. In epee competition, the valid touch signal constitutes the breaking of the circuit between the terminals B-C, and the making of the circuit between the terminals B-A. Another delay circuit, including

resistors

250 and 252, and a capacitor 254, is connected to the left-hand terminal of the switch 94. When the B-C terminal circuit is broken, the potential of terminal B rises,.and when the B-A terminal circuit is completed, a positive voltage is applied to the delay circuit including the

resistors

250, 252 and the capacitor 254. Following the delay imposed by the

resistors

250, 252 and the capacitor 254, the positive voltage is applied to the breakdown diode 130, after which the SCR 120 is fired in the manner as in the case of foil competition described above.

Providion is made for preventing actuation of second valid touch indicator Cy after the lapse of 1/25th of a second (40 milliseconds) following the actuation of the valid touch indicator Cx. The components of the first delay circuit including the unijunction transistor 104, the

resistors

102 and 110, and the capacitor 106 are used to accomplish this purpose. This is in addition to the function of these elements in preventing the actuation of the invalid touch indicator Wx by invalid touch signals less than 8 milliseconds in duration, as has been explained above.

To accomplish this dual function, the output of the first delay appearing at the top of the SCR 100 at point 113 is redirected from the invalid touch indicator Wx to means for disabling the actuating circuitry of the second valid touch indicator Cy. The time constant of the first delay is changed by connection of additional circuitry thereto to provide for indication of the 40 millisecond time lapse during which simultaneous touches may be made in epee. The first delay is actuated through the additional circuitry to produce its output in response to actuation of the valid touch indicator Cx.

The value of the voltage at the point 113 selectively controls disabling of the valid touch indicator Cy. The output 113 is connected by a line 270 to the terminal B. When the voltage of the output at the upper teminal of the SCR 100 drops, in response to the firing of the SCR 100, the terminal'B' is grounded and the valid touch indicator Cy can no longer be actuated. Firing of the SCR is accomplished by operation of the first delay.

The time constant of the first delay circuit is increased by addition of circuitry to its RC timing branch. A resistor 260, connectable in series with the RC branch of the first delay including resistor and the capacitor 106, is connected at its upper terminal to the collector of a transistor 262. The time constant change is accomplished by electronically switching the resistor 260 into series with the resistor 110 and the capacitor 106.

This is done by appropriate control of the transistor 262. When the valid touch indicator Cxis not actuated, the terminal 136 is at a relatively high potential, which potential is transmitted through the lead 142 to the base of transistor 262, rendering that transistor conductive. In its conductive state, power applied to the collector terminal of the transistor 262 proceeds virtually unimpeded to the emitter terminal of the transistor 262, and the upper terminal of the resistor 260 is effectively grounded to the low voltage lead 86. In this condition, virtually no electrical potential is applied across the RC branch represented by the

resistors

260 and 110, and the capacitor 106, and the first delay circuit is not actuated.

When the circuit between the terminals B-C is broken, the potential at the terminal B rises, and this rising potential is applied by way ofthe closingof the B-A terminal circuit to actuate the valid touch indicator Cx. When the valid touch indicator Cx is actuated. the terminal 136 drops to a relatively low potential, which is transmitted to the base of the transistor 262, rendering that transistor nonconductive. When the transistor 262 becomes nonconductive, power from the high voltage line 84 is diverted through the RC branch of the delay circuit, including through the resistor 260. The delay circuit then operates in a fashion similar to that in which it operates in foil competition, (except with a different time constant) producing an output on lead 112 as a result of the firing of the unijunction transistor 104 after a predetermined time.

Preferably, for epee competition, the value of the resistor 260 is chosen such that the resistor 260 in combination with the resistor 110 and the capacitor 106 will yield a time constant for the RC branch which results in the firing of the unijunction transistor 104 approximately 40 milliseconds following the actuation of the valid touch indicator Cx.

FIG. 4 shows in detail a typical touch sensor assembly 16 for a foil. The touch sensor assembl y 16 generates valid and invalid touch signals in accordance with touches executed with the foil. For the purposes of this discussion, the touch sensor assembly 16 shall be considered to be connected to the terminals A, B, C of the indicator control circuit 36.

The sensor assembly 16 is mounted on the tip of a foil. A hollow blade 300 of a foil is shown in FIG. 4, having a threaded portion 302 at its outer end. A sleeve 304, generally enclosing the other components of the sensor assembly 16 is threadedly engaged with the threaded portion 302 of the blade 300. Both the sleeve 304 and the blade 300 are made of a conductive material.

A plunger 306 is mounded for slidable movement within the sleeve 304. The plunger 306 fits generally slidably into a collar 310 mounted inside and concentric with the sleeve 304, for motion in the direction of the arrows 307. The collar 310 is supported by conduction elements 311 stationarily with respect to the sleeve 304.

A spring 314 is mounted between the blade 300 and the plunger 306 in order to resiliently bias the plunger 306 toward an outwardly extending position with respect to the sleeve 304. The plunger 306 has a conductive base member 316 conductively connected to the plunger. The extent of permitted outward movement of the plunger is limited by the engagement of the outer portion of the base member 316 with the collar 310.

Electrical connections among the various components of the touch sensor assembly generate the invalid and valid touch signals. The collar 310 is electrically insulated from the plunger 306. An insulating coating 320, preferably made of a plastic material, extends about the plunder 306. When the plunger is in its outermost position collar 310 is electrically connected to the base member 316.

When the plunger 306 is in tis outermost position, it is also electrically connected to the sleeve 304, and to the blade 300 by way of the conductive members 311.

The plunger 306 and its base member 316 are electrically coupled to the spring 314, which in turn is electrically connected to a lead 324. The lead 324 is connected to the terminal B of the indicator control circuit 36, by conventional electrical coupling means, (not shown). The blade 300 is electrically connected to the terminal C of the indicator control circuit 36 by way of further conventional electrical coupling structure (not shown).

When the plunger 306 is in its outer most permitted position, the terminals B and C of the indicator control circuit 36 are electrically connected together. The circuit between the terminals B and C is completed through the lead 324, the spring 314, the base member 316, the collar 310, the conductive elements 311, the sleeve 304, and the blade 300. This condition endures as long as the plunger 306 is in its outermost permitted position of movement.

When the plunger 306 is depressed, as in the instance of a touch against any object, such as in the 'case of an invalid touch against an opposing fencer, the electrical connection between the collar 310 and the base member 316 is broken, interrupting the circuit between the terminals B and C. The interruption of the circuit between B and C represents an invalid touch signal, produced in response to the execution of an invalid touch with the foil of which the blade 300 is a part.

The depression of the plunger 306 against a conductive surface connected to the terminal A of the indicator control circuit 40 generates a valid touch signal. When the plunger 306 is depressed by contact with a conductive surface connected to the terminal A, the circuit between the terminals B and C is interrupted, in the manner described above' with respect to the generation of an invalid touch signal. Additionally, the circuit extending between the terminals B and A becomes completed, by way of contact of the conductive plunger 306 with the conductive surface of the vest of the opposing fencer, (which as described above, is con nected to the terminal A of the indicator control circuit 40) and by way of the spring 314.

FIG. 5 shows a touch sensor assembly for use in connection with the epee. The touch sensor assembly generates valid touch signals in response to the execution of valid touches with the epee on the body of the opposing fencer.

The components of the touch sensor assembly are generally mounted within a sleeve 330 which is attached to a blade portion 332 of an epee by means of threaded engagement with the threaded portion 334 of the blade portion 332. The sensor assembly includes a plunger 336, an annular member 338, a contact 340 on one end of the plunger 336, a spring 342, and a pair of terminals designated 344 and 346.

The valid touch signals are derived by motion of the plunger 336 within the sleeve 330 resultant on touches made by the plunger 336 against the opposing fencer. Depression of the plunger 336 results in the completion of the circuit between the terminals A and B of the indicator control circuit 36.

The plunger 336 slides movably within the sleeve 330 l by engagement with the annular member 338 mounted concentrically within the sleeve 300. The contact 340 is aligned across the

terminals

344 and 346. The spring 342 is interposed between the contact 340 and the

terminals

344 and 346, and serves to maintain the plunger and the contact 340 in a normally extended position from the sleeve 330. Upon depression of the plunger 7 336 such as by way of a touch, plunger 336 moves inwardly and to the left as shown in FIG. 5, and closes the contact 340 across the

terminals

344 and 346, completing the circuit therebetween. The contact 344 is con: nected to the terminal A of the indicator control circuit 36 by way ofa lead 350. The terminal 346 is connected to the terminal B of the indicator control circuit 36 by a lead 352.

As has been explained above, a valid touch signal in epee competition is represented by the completion of the circuit extending between the terminals A and B of the indicator control circuit 36, with the circuit between the terminals B-C being open.

When an errant touch is made in epee against a surface which is not a part of the opposing fencers body,

the touch sensor assembly renders the indicator control circuit inoperative to indicate a valid touch. This is done by grounding out the terminal B of the indicator control circuit whenever the conductive plunger 336 is touched against such a surface, and by defining such off possible the actuation of the valid touch indicator Cx in response to such a touch.

Preferably, the piste is grounded to define an offtar get surface. Likewise, the body of the epee, including the blade 332, the sleeve 330, and the bell portion (not shown) is grounded to the low voltage lead 86, so that depression of the plunger 336 against the piste or the body of the opponents weapon will likewise prevent actuation of a valid touch indicator in response to such a contact.

What is claimed is: 1. An electrical apparatus connectable to a power supply for scoring a fencing match. in response to touch signals indicating at least one of valid and invalid touches executed with a fencing weapon, said apparatus comprising:

a. an invalid touch indicator; b. a valid touch indicator; c. an indicator control circuit for actuating said valid and invalid touch indicators in response to the occurrence of valid and invalid touch signals, respectively, the indicator control circuit comprising a first delay circuit for preventing actuation of said invalid touch indicator in response to invalid touch signals of less than a predetermined duration, to prevent actuating said invalid touch indicator in response to spurious signals, not actually representing invalid touches.

2. The apparatus of claim 1, wherein said predetermined duration is approximately 8 milliseconds.

3. An electrical apparatus for scoring a fencing match, in response to at least one valid touch signal produced by execution of at least one valid touch with a fencing weapon, said apparatus comprising:

a. a valid touch indicator; and

b. An indicator control circuit connected to said valid touch indicator for actuating said valid touch indicator in response to the occurrence of a said valid touch signal, said indicator control circuit comprising a second delay circuit connected to said valid touch indicator for preventing the actuapredetermined amplitude, to prevent actuation of the valid touch indicator by noise signals not representing valid touches. 6. The apparatus of claim 5, in which the amplitude sensor comprises a breakdown diode.

7. An electrical apparatus for scoring fencing matches in response to first and second valid touch signals and invalid touch signals produced by execution of first and second valid and invalid touches with fencing weapons, said apparatus comprising:

a. an invalid touch indicator;

b. first and second valid touch indicators;

c. an indicator control circuit comprising:

i. first means for actuating said first valid touch indicator in response to a first valid touch signal. ii. second means for actuating said second valid touch indicator in response to a second valid touch signal,

iii. a first delay circuit producing an output signal capable of actuating the invalid touch indicator upon a predetemined time lapse after the initiation of an input signal thereto;

iv. first control means for initiating said input signal to said first delay circuit in response to selected first valid touch signals, and

v. second control means for selectivelydirecting said output of said first delay circuit to disable said second means from actuating said second valid touch indicator in response to said second valid touch signals following said predetemined time lapse.

8. The apparatus of claim 7, further comprising:

converting means connected to said first delay circuit for changing the magnitude of said time lapse between initiation of said input signal and production of said output signal.

9. The apparatus of claim 8, wherein said changed predetermined time lapse is approximately 40 milliseconds to enable scoring of simultaneous valid touches in epee fencing competition. 7

10. The apparatus of claim 9, wherein:

a. said first delay circuit comprises a series RC branch having a time constant; and

b. said converting means comprises:

i. an additional resistive element, and ii. electronic switching means for connecting the additional resistive element in series with said series RC branch to change its time constant.

5 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,920,242

DATED :November 18, 1975 |NV ENTOR(S) William E. Reith and John A. Overman It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Q Col. 2, line 9, add s to "opponent' Col. 3, line 20, change "not" to -no-;

Col. 4, line 27,change "the" to --this--;

Col. 4, line 46, change "viow" to v'iew--'-;

Col. 7, line 19, change "Ppwer" to -Power-;

Col. 8, line 52, after 124, change the period to a comma Q Col. 9, line 36, change "curcuit" to -circuit;

Col. 10, line 8, change "aa" to --a;

Col. 10, line 37, change "the" to -The Col. 10, line 56, change "preferably" to -Preferably-;

Col. 12, line 45, after "the" first occurrence, insert -values of the-; v

Q Col. 13, line 39, change "Providion" to -Provision;

Col. 15, line 20, after "in", change "tis" to -its.

twent ourth [SEAL] yf Day Of February 1976 A ttes t:

RUTH C. MASON C. MARSHAL D Arresting Ojficer L ANN ommissl'uner oflatenls and Trademarks

Claims

1. An electrical apparatus connectable to a power supply for scoring a fencing match in response to touch signals indicating at least one of valid and invalid touches executed with a fencing weapon, said apparatus comprising: a. an invalid touch indicator; b. a valid touch indicator; c. an indicator control circuit for actuating said valid and invalid touch indicators in response to the occurrence of valid and invalid touch signals, respectively, the indicator control circuit comprising a first delay circuit for preventing actuation of said invalid touch indicator in response to invalid touch signals of less than a predetermined duration, to prevent actuating said invalid touch indicator in response to spurious signals, not actually representing invalid touches.

3. An electrical apparatus for scoring a fencing match, in response to at least one valid touch signal produced by execution of at least one valid touch with a fencing weapon, said apparatus comprising: a. a valid touch indicator; and b. An indicator control circuit connected to said valid touch indicator for actuating said valid touch indicator in response to the occurrence of a said valid touch signal, said indicator control circuit comprising a second delay circuit connected to said valid touch indicator for preventing the actuation of said valid touch indicator in response to signals having a duration less than a predetermined period to avoid actuation of the valid touch indicator by noise signals not representing valid touches.

4. The apparatus of claim 3, wherein: said second delay circuit comprises a resistive and a capacitive element connected in parallel.

5. The apparatus of claim 3, wherein said indicator control circuit further comprises: an amplitude sensor for preventing actuation of the valid touch indicator by signals having less than a predetermined amplitude, to prevent actuation of the valid touch indicator by noise signals not representing valid touches.

6. The apparatus of claim 5, in which the amplitude sensor comprises a breakdown diode.

7. An electrical apparatus for scoring fencing matches in response to first and second valid touch signals and invalid touch signals produced by execution of first and second valid and invalid touches with fencing weapons, said apparatus comprising: a. an invalid touch indicator; b. first and second valid touch indicators; c. an indicator control circuit comprising: i. first means for actuating said first valid touch indicator in response to a first valid touch signal, ii. second means for actuating said second valid touch indicator in response to a second valid touch signal, iii. a first delay circuit producing an output signal capable of actuating the invalid touch indicator upon a predetemined time lapse after the initiation of an input signal thereto; iv. first control means for initiating said input signal to said firSt delay circuit in response to selected first valid touch signals, and v. second control means for selectively directing said output of said first delay circuit to disable said second means from actuating said second valid touch indicator in response to said second valid touch signals following said predetemined time lapse.

8. The apparatus of claim 7, further comprising: converting means connected to said first delay circuit for changing the magnitude of said time lapse between initiation of said input signal and production of said output signal.

9. The apparatus of claim 8, wherein said changed predetermined time lapse is approximately 40 milliseconds to enable scoring of simultaneous valid touches in epee fencing competition.

10. The apparatus of claim 9, wherein: a. said first delay circuit comprises a series RC branch having a time constant; and b. said converting means comprises: i. an additional resistive element, and ii. electronic switching means for connecting the additional resistive element in series with said series RC branch to change its time constant.