05/132356

05/01/1973

04/08/1971

Download PDF 3731298       PDF help

Click for automatic bibliography generation

340/573.100

340/323R, 482/8, 200/61.45R, 482/19, 340/669

A63K3/02; A63K3/00; G08B21/00

340/323,262 200/61.45,DIG.29 272/59A,4

Trafton, David L.

What I claim as my invention and desire to secure by Letters Patent of the United States is

1. In a switching device for a control circuit, especially for ascertaining false starts in athletic events, wherein the switching device is combined with a starting apparatus, the improvement comprising inertia switching means, means for rigidly but exchangeably attaching said inertia switching means to any starting apparatus, said inertia switching means comprising an electrically conducting inertia body, an insulating block, a channel in said insulating block for movably receiving said electrically conducting inertia body in said channel, and contact elements reaching through said insulating body into said channel whereby a circuit is closed between said contact elements by said conducting inertia body in response to movement of said starting apparatus.

2. The device according to claim 1, wherein the inertia body is a metal ball.

3. The device according to claim 1, wherein the inertia body is a conductive liquid.

4. The device according to claim 1, wherein said channel is an inclined bore in said insulating block.

5. The device according to claim 1, wherein said control circuit comprises a plurality of switching devices each of which is associated with a respective starting apparatus, a respective plurality of bi-stable, controllable semiconductor switch means connected to the corresponding switching device, a control conductor common to all of said semiconductor switch means, whereby the triggering of one of said semiconductor switches by the closure of its respective switching device changes the potential on said common control conductor for the other semiconductor switches so that no other semiconductor switch can be triggered.

6. The device according to claim 5, wherein each of said semiconductor switches is a thyristor.

7. The device according to claim 5, comprising a second control conductor, individual diodes for connecting said semiconductor switches to said control conductor, whereby positive supply voltage is fed through an individual one of said diodes to said second control conductor in response to the triggering of one of said semiconductor switches, said device further comprising a first transistor, means for connecting the collector of said first transistor to said first control conductor and a common diode for connecting the base of said first transistor to said second control conductor whereby the first transistor becomes conductive to apply zero potential to said first mentioned control conductor from the collector of the first transistor.

8. The device according to claim 7, comprising a variable delay element connected between said common diode and said first transistor, whereby to detect a number of premature starts within a predetermined selectable time interval.

9. The device as claimed in claim 4, wherein with a normal start, the firing of a starting pistol closes a circuit which triggers a monostable trigger stage, which after a predetermined reproducible delay time reverts to the stable condition to drive a second transistor, wherein the resultant brief blocking of said second transistor triggers a further bi-stable semiconductor switch to cause a lamp to light up and to cause said first transistor to go conductive to apply zero potential to said control line.

10. The device as claimed in claim 9, wherein the circuit of each of said bi-stable semiconductor switches includes an indicating lamp located at the respective starting position.

11. The device as claimed in claim 10, wherein in the presence of a positive voltage change on said control conductor a third transistor becomes conductive for energizing an electromagnetic cocking catch of a starting pistol, or for rendering non-conductive a fourth transistor which is controlled by said third transistor and is located in the circuit of an electrical starter to inhibit the production of a starting signal.

The present invention relates to devices for detecting false starts in athletic events.

It is known to provide a contactor at the back end of a starting block and an electronic monitoring circuit controllable by the contactor, which circuit maybe in a first operative condition indicating readiness to start, or in a second operative condition indicating a false start, a false start indicator means being controllable by the monitoring circuit.

In known devices of this kind, the monitoring elements at the starting blocks consist of mechanical, spring-loaded contacts which are either closed by pressure and open again under the force of a spring, when the load is removed, as described in German Patent Specification No. 1 899 612 or of mechanically, spring-loaded contacts which are opened at a specific pressure and after the force of a spring has also been overcome, as described in French Patent Specification No. 1 507 905.

The first of the said known devices is based upon the conception that the initial reaction of a starting runner is to lift his feet from the starting block. However, in order for a runner to transfer from a stationary condition to a condition of movement, it is necessary first to exert a force on a fixed object. The initial reaction, therefore, cannot be indicated in this way.

The second of the known devices, whilst commencing from the correct premise, namely that the first reaction of a starting runner is to exert pressure on the starting leg, nevertheless has the drawback that a break contact is kept closed under the action of a spring and a certain contact travel is bound to take place before the contact opens. Break contacts (especially in the microswitches which are most generally used), more often than not have a dead travel of up to 2 mm before the contact spring changes over, and this corresponds to a switching time of about one one-hundredth sec. If we assume the complete switching time to be a minimum of one one-hundredth sec., then on this basis a world-class runner could have moved as much as 10 cm forwards, and this is a distance which could be critical when the securing of a win is concerned.

The use of contacts furthermore has the drawback that these either have to be installed in the starting block in order to be actuated by a thrust plate operated by the runner, so that the runner has to do without his own, accustomed starting block, or, the contacts have to be separately fitted behind the starting block so that then the runner cannot arbitrarily choose the position of the block. Thus, the runner's individual freedom to determine the type and location of the starting block, is lost.

An object of the invention is to avoid the drawbacks of known devices and to provide an acceptable false start indicating device whose dead time is determined only by the switching time of a key contact which can have a maximum contact spacing of 0.5 mm, and the switch-in time of a thyristor (t = 10 μs), this dead time not only being well below the reaction time of any runner but also depending upon the speed of reaction of a runner. Also the invention provides that the false start indication does not bar the runner from individually selecting and setting-up his own starting block.

The invention therefore consits in a device for detecting false starts in athletic events, including a contactor associated with a starting block, an electronic monitoring circuit controllable by said contactor, which circuit may be in first operative condition indicating readiness to start or in a second operative condition indicating a false start, and a false start indicator means controllable by the monitoring circuit, wherein said contactor is an inertia switch.

A conductive inertia body in the switch may consist of a metal component such as a metal ball but a conductive liquid may be used. The conductive body may be housed in an inclined bore formed in a non-conductive material, said bore containing two electrodes which can be bridged by the said body when the latter is displaced.

The switching times of a spring-loaded contact are thus cut out, and each runner has absolutely free choice of starting block and its setting up, it being then merely necessary, once the starting block has been set up in accordance with the runner's requirements, so fit the aforementioned block containing the conductive body.

Detection of the bridging of the contacts may be effected by connecting each contactor to a bistable, controllable semiconductor switch such as a thyristor which, when triggered, so alters the potential of a control line common to other contactor-controlled semiconductor switches, that none of the others can trigger. The individual reaction time of each runner is thus taken account of and all the functions necessary to the unambiguous identification of the first runner to make a false start, are initiated by the disconnection of the common control line to all the thyristors. The functions of the electronic monitoring circuit are triggering the thyristor operated by the false starter to a stable condition even when this runner subsequently returns to the initial position; switching in of the relevant false start indication; disconnection of the common control line to all the other thyristors so as to prevent indication of mis-starts by other runners who have possibly been made jumpy by the first false starter; and possibly the switching-in of a start-inhibit function.

A switch in the common circuit to all the false start thyristors, is preferably provided, which, when the starter pistol is triggered, is briefly closed. In this way, when the starting signal is triggered, the triggering of a specially-provided thyristor causes the control line to all the other thyristors to be disconnected so that, in the case of a normal start, no doubts can arise about the correctness of the start as a consequence of a false start indication which would otherwise be initiated by the first runner to start properly.

An exemplary embodiment of the invention will now be described with reference to the drawings forming part of this specification, in which:

FIG. 1 is a section through a contactor which is attached to a starting block; and

FIG. 2 is an electrical circuit diagram of a device in accordance with the invention.

FIG. 1 shows a contactor one of which is provided for each runner at the starting line. Each of these contactors K1 . . . Kn, FIG. 2, is attached to the back of an associated starting block by means of the attachment bolts (for use on ash tracks) with which each commercially-available starting block 6 is provided. If a plastic track is being used, the contactor is attached to the starting block by means of the screw which at the same time secures the flat back rail 7 to the block 6 which rail carries the spikes 8. Each of the contactors K1 . . . Kn consists of an electrically non-conductive block 1 which is provided in the longitudinal direction with one or two bores sloping obliquely downwards away from the running direction. Each of these bores contains a freely-movable metal ball 2 which, in the rest position, is located at the lowermost part of the bore. In each of the bores there is also housed a carrier 4 equipped with two contacts 3 and 3a which are insulated from one another, the carrier being disposed in such a way that the contacts 3 and 3a are located at a small distance from the metal ball 2. From each of the two contacts, a lead goes to a respective busbar located a suitable distance behind the starting block, said busbar being connected to the electronic monitoring system. The block 1 is fixed to a flat rail 5 which is secured to the starting block 6. When a runner thrusts forward away from the starting block 6 at the start of a race, the block is thrust to the rear. This sudden, heavy thrust is sufficient to displace the metal ball 2, due to its inertia, into contact with the two mutually-insulated contacts 3 and 3a, thereby bridging them. The ball then rolls back to its initial position under its own weight. Oscilloscope measurements have shown that the time elapsing between the starting thrust of a runner's foot, and the bridging of the two contacts 3 and 3a, where an interval of 1mm is provided between the ball and the contacts, is less than 0.1 ms. This method of contact closure is thus far superior to all the mechanical, spring-loaded switches thus far known. Any bounce contacts which take place can by completely disregarded because the initial single pulse furnishes an unambiguous criterion to the electronic monitoring system.

The second monitoring element, of the same kind, which is installed in the contactor is provided to measure the reaction times of individual runners in the event of a false start or a normal start when the starting pistol has been fired. In this way it is possible simultaneously to detect the sequence of starting of the individual runners, using known electrical monitoring equipment.

The electronic monitoring system of FIG. 2 incorporates for example ten starting positions marked I to X and x arbitrary other starting positions marked n, each of these being equipped with a contactor of the kind shown in FIG. 1. Each contactor K1 . . . Kn has its two contacts 3 and 3a located in the control circuit of a respective thyristor Th1 . . . Thn whose anode circuit in each case contains an individual indicating 1amp Lp1 . . . Lpn, in the monitoring system, and also an individual indicating 1amp Lp11 . . . Lpp at the particular starting position, series resistors R1 . . . Rn being connected in the 1amp circuits in order to limit the current. Furthermore, from the anode of each thyristor Th1 . . . Thn a lead passes via a respective diode D1 . . . Dn to a common control line m and via a further diode D11 and a resistor R11 to the base of a switching transistor Ts1 which represents the decisive monitoring element of the overall monitoring system. The collector circuit of this transistor contains the control line S which, depending upon whether the transistor Ts1 is driven conductive or not, is placed at the switching speed of the transistor in the zero potential condition or in the condition corresponding to the supply voltage. The circuit of the transistor Ts1 is so designed that the transistor goes conductive in less than 100 ns when operated.

The monitoring system of FIG. 2 also comprises a monostable trigger stage MK which is converted to the unstable state by a brief closure of a pistol contact PK. The triggering time can be reproducible set at between one one-hundredth sec. and three-tenth sec. by changing the resistance of the resistor Rv. In this way both the acoustic delay of the pistol-shot and the minimum reaction time of the runners, can be taken account of. The pulse from the monostable trigger stage is fed through a differentiating circuit DE comprising a capacitor C, a resistor R and a diode D, to drive a further switching transistor Is2 whose collector resistor R22 is taken to the control line S which is connected to the collector of the transistor Ts1.

In the quiescent condition, the transistor Ts2 is continuously conductive, i.e., its collector is at zero potential, taking into account collector-emitter residual voltage. The collector of the transistor Ts2 drives the gate of a thyristor ThA, through a resistor R23. The thyristor ThA triggers after the starting pistol is fired if previously, or during the delay determined by the monostable trigger stage MK, there is no false start. If the thyristor ThA strikes, the transistor Ts1 is driven conductive through the diode D12. At the same time, the anode of the thyristor ThA energizes a relay ZM through a capacitor. The period during which the relay contacts are closed depends upon the capacitance of the capacitor. Through the brief closure of the contacts of the relay ZM, electrical timing is controlled. The control line m is at zero potential in the inoperative condition, but with ignition of one of the thyristors Th1 . . . Thn and neglecting the voltage drop across the anode-cathode region of such a thyristor has positive supply voltage applied to it through one of the diodes D1 . . . Dn. The base of a transistor Ts3 is thus driven to energize the electromagnetic cocking catch Sp of the starting pistol.

The time elapsing until the energizing of the pistol-cocking catch, depends upon the switching times of the thyristors Th1 . . . Thn and the diodes D1 . . . Dn, and the order of magnitude of the overall time depends largely upon the design of the electrical circuit but, without any special measures, it is less than 10 μs. An electrical starter EP can be deenergized in the event of a premature i.e., false start. For this purpose the collector of the transistor Ts3 for the electromagnetic pistol-cocking catch, drives a further transistor Ts4 which is included in the circuit of an electric starter and de-energizes the latter in the event of a false start. In the event of a false start, in addition to an ancillary, intermittent optical indication, an acoustic indication can be used which in a manner which is not shown but can be performed by an astable trigger stage in association with relays, is influenced by the control line m.

The function of the circuit thus far described will now be explained in the context of a false start occurring at position I. If, before the starting pistol goes off, or during a reproducible, predetermined time of operation of the monostable trigger stage MK, the two contacts 3 and 3a of the contactor K1 are closed briefly by the metal ball 2, as a consequence of the back thrust of the starting runner, then the thyristor Th1 triggers. Its cathode, except for the anode-cathode voltage drop, consequently has positive supply voltage applied to it. The 1amp Lp1 in the start monitoring system and a second 1amp Lp11 located on the starting block, both of which 1amps are in the circuit of the thyristor Th1, light up and visually indicate the false start at starting position I. The control line m now receives a positive potential corresponding substantially to the supply voltage through the diode D1. When the control line m becomes positive, the transistor Ts3 goes conductive and energizes the electromagnetic cocking catch Sp of the pistol, or the transistor Ts4 which is controlled by the transistor Ts3 and located in the circuit of an electrically-fired pistol EP which might be used as an alternative, has its current supply cut off. At the same time, via the diode D11 and the resistor R11, the positive potential on the control line m is applied to the base of the transistor Ts1. This transistor is the most important element of the entire electronic monitoring system. When driven positively, it becomes immediately conductive, i.e., its collector and therefore the control line S, have zero potential applied to them. Consequently, one of the remaining thyristors Th2 to Thn can trigger because the requisite ignition voltage is no longer present on the control line S. Moreover, the thyristor ThA cannot strike because before the starting pistol is fired or during the triggering time of the monostable trigger stage MK, the collector of the switching transistor Ts2, which is connected through the resistor R22 to the collector of the transistor Ts1, ceases to carry current although the monostable trigger stage MK is briefly rendered unstable by a starting shock and drives the base of the transistor T52 through the circuit DE.

Any false start at any of the other starting positions II . . . n will initiate a similar switching process to that just described.

With a normal start, the firing of the starting pistol means that the pistol contact PK is briefly closed. Consequently, the monostable trigger stage MK changes to the unstable condition and, after the time determined by the variable resistor Rv, reverts to its initial state and thus drives the transistor Ts2 through the circuit DE. This transistor is continuously conductive in the quiescent condition and when the monostable trigger stage MK relaxes, briefly has its current cut off, i.e. its collector is supplied through the resistor R22 with full positive supply voltage because the transistor Ts1 is also still disconnected. This short positive voltage pulse passes through the resistor R23 to the gate of the thyristor ThA and causes the latter to strike. Through the triggering of the thyristor ThA, the diode D12 becomes conductive and drives the base of the transistor Ts1 positive. Consequently, this transistor conducts and the control line S contained in its collector circuit has zero potential applied to it. Because all the thyristors Th1 . . . Thn are supplied from the control line S through the contactors K1 . . . Kn, the triggering of all the other thyristors is inhibited because a positive voltage and current pulse of corresponding magnitude is needed to make a thyristor strike. At the same time, with the striking of the thyristor ThA the indicating 1amp LpA lights up, showing that the start has been normal. The relay ZM is energized through the associated capacitor by the cathode of the triggered thyristor ThA to start the electrical timing function and its contacts open again after the capacitor has discharged. In order to prepare the electronic monitoring system for renewed monitoring, after a correct start or a false start, a recall key RHT is briefly depressed so that all the thyristors Th. . . n and ThA are disconnected from the supply voltage and thus extinguished.

The contactors may take the form of a liquid switch, the liquid having good electrical conductivity and being for example mercury. This liquid switch must be so installed in the non-conductive block 1 that in the inoperative condition, the conductive liquid does not touch the two contacts 3 and 3a but does do so, electrically bridging them, when impelled by the back thrust of the starting runner's foot. In this form of contactor the adhesion and cohesion of the conductive liquid, as well as its coefficient of expansion, have to be taken into account, so that generally the metal ball design is to be preferred.

The facility can be provided for detecting not merely the first false starter but also all those runners who make a false (premature) start within a certain time interval, e.g. five one-hundredth sec., after the first false starter. This ensures that none of the other false starters can justifiably complain that they have been put off by the first false starter, because this very brief time interval excludes the possibility of any human reaction. This facility is provided by arranging an adjustable delay element of known kind in series between the diode D11 and resistor R11 of FIG. 2.