US3170689A

US3170689A - Foul detecting system with transistor output switch

Info

Publication number: US3170689A
Application number: US190536A
Authority: US
Inventors: Raymond E Brown; Thomas A Crugnale
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-04-27
Filing date: 1962-04-27
Publication date: 1965-02-23
Anticipated expiration: 1982-02-23

Description

Feb. 23, 1965 R. E. BRowN r-:TAL

FOUL DETECTING SYSTEM WITH TRANSISTOR OUTPUT SWITCH Filed April 27, 1962 2 Sheets-Sheet 1 M n, P

INVENToR iwi wnwwu Mom.

NMI

AyMoA/o E. BROWN 7Z/oMAs Afef/NALE ATTONE Y j 3,170,689 FOUL DETECTING SYSTEM WITH TRANSISTGR OUTPUT SWITCH f g,

Raymond E. Brown, l765 Hazelvalley, Hazelwood, Mo.,

and Thomas A. Crngnale, Woodson Terrace, Mo.

(9201 Gedde, St. Louis 34, Mo.) y

Filed Apr. 27, 1962, Ser. No. `190,536 3 Claims. `(Cl. 273-50) This invention relates inV ,general to foul ldetection systems for use in bowling lalleys and the like, and more particularly to foul detection systems in which all controls are electronic and electronicallyope'rated.

At the present time, foul detection systems .as used in bowling alleys are composed of a combination of electrical and mechanical devices, including relays, gears, motors, mechanically-operated switches and the like. Because of the large number of moving parts associated therewith, this equipment-inherently requires repeated maintenance in order Vto be kept in satisfactory operating condition, which said maintenance results in vunusually highcost to the owners and operators of such equipment. It is the primary object of the present invention to provide a foul detection system which, except for a sound producer, is purely electronic in structure and operation and which employs no other moving parts.

It is also an object of the present invention to .provide a foul detection system of the typedescribed in which the said system can electronically distinguish between the passage of a bowling ballor the like over a foul line and the passage. of ahuman foot over the said foul line.

With the above and Aother objects in view, which will become apparent upon vreading the lfollowing description, our invention resides -in the novel features of -form, conf struction, arrangement and combination of parts 'presently described and pointed out in the claims.

In the accompanying drawings:

FIGURE 1 is a schematic block diagram of anembodin ment of ourinvention as used in a pair of adjacent bowling lanes;

FIGUREZ is an electrical schematic diagram thereof;`

FIGURE 3 is anend view of ,a typical pair of bowling lanes showing the position of the beams with'respect to the floor and therails. Y

Referring now in more detail andby reference character to the drawings, which illustrate va preferred embodiment vof the present invention, A designates a bowling alley comprising a pair of adjacent bowling lanes 10, 12,

denedby spaced

parallel gutter rails

14, 16, 18, and rcto v50 spectively provided with lregulation foul lines 20, 22, the crossing ofwhich will cause that particular bowler forfeit his score for that particular throw. n

Mounted on the rail 16 and respectively presented to the

complementary rails

14, 18, in alignment with the foul lines 20, 22, respectively, are conventional

light beam projectors

24, 26, which are conventionally coupled to a source of electrical power 28 and which project beams R and R', respectively, across the lanes 10, 12, above the foul lines 20, 22, respectively. Mounted in the rail 14 in alignment with the foul line 20 and the vbeam projector 24, is a photocell 30 provided with a cathode 32 which is connected toia source of negative potential designated as `B and a plate 34 which is connected to the `input 'terminall 36 of a current amplifier 38, also prot vided with an output terminal 40;v similarly mounted'in the rail 18 and 'in alignment with the foul Vline 22 and the lbeam projector `26v is a photocell 42 including a cathode`44 connected to B, and a plate 46 which is the input terminal 54 of rva unilateral isolator 56 having 3,170,689 Patented Feb. 23, 1965 ice also an output terminal 58 4and an indicator light igniting circuit 60 comprising a single-shot multivibrator net- `work 62, a current amplifier 64,'and an electronic switch .n fascia board F above the lanes 10, 12.y

Similarly connected to the output terminal 52 of th i n current amplifier l50 is the input terminal 70 of a uni,

lateral isolator 72, also having an output terminal 74, and an indicator light igniting network 76 comprising a single-shot multi-vibrator network v78, a current amplifier 80, and an electronic switch 82, and an indicator light 84, all connected in series respectively'from the output terminal 52 of the current amplifier 50.

The

output terminals

58, 74, of the unilateral isolators V56, 72, respectively, are connected together and to a bell ringing circuit 86 comprising a single-shot multi-vibrator Vnetwork 88, a current amplifier 90, and an electronic switch 92, and a bell `94, all connected in series.

The current amplifier 38 includes a potentiometer 100,

the tap of which is electrically connected to the base of a transistor 102 and the input terminal 36. One end of the potentiometer 100 is connected through a resistor 104 to B- and the other end of the potentiometer 100] is connected through aresistor 106 to a source of positive potential designated as B+. The collector of the transistor 102 is directlyv connected to B and the emitter of the transistor 102 is connected to the base of a second transistor 108 and through a resistor 110y to B+. The emitter of the transistor 1.08 is connected'to a source of zero potential, or ground, and the collector thereof is connected to the output terminal 40 of the current amplier 38 and through ,a resistor112 to B+.

Connected to the input terminal 36 of the current-amplifier 38 is a capacitor 114, one plate of which is connected to ground. Connected to the output terminal 40 of the current amplifier 38 is a variable capacitor 116, also having one of its plates `connected to ground.

Connected to the output terminal 40-of the current amplifier 38 is the single-shot multi-vibrator 62 compris-` ing a transistor 118 having ,a base which is connected to the output terminal 40 vthrough a resistor 120 4and which is also connected to B+ through ya resistor y122. The

emit-ter of the transistor 118' is grounded and the colofthe transistor 130 is connected to ground and the'collector is connected to B-through a resistor.,136, to ground through a capacitor 138, and to the base of the transistor 118 through a resistor 140. y

The current amplifier 64 comprises a transistor y142, the base of which is connected to the collector ofthe transistor 130 through a resistor 144 and to B+ through connected to theinput terminal 48 of a current amplifier.l

a resistor 146. The emitter of the transistor 142 is grounded and the collector of the transistor 142 is connected to` B- through two resistors, V148, 150,*connected to each other in series. y

Connected to the common juncture of the resistors 148, 150, is the base of a'transistor 152, 1the emitter of which is directly'connected to B+, and the collector of which is connected to the -base ofa second transistor 154 through a resistor 156. The base of the transistor 154 is alsoconnected to B+ through a resistor 158. vThe emitter of the transistor 154 isV connected directly to ground, and the collector of the transistor154 is eonnected through the indicator light 68 toone terminal of Y the secondary coil 1600i a step-down transformer 162,

the other terminal of the secondary coil 160 being connected to ground, for purposes presently more fully to appear.

TheA electrical circuitry for the current amplifier 50 is identical with the electrical circuitry for the current wamplier 38, and similarly the circuitry for indictor igniting networks 60 and 76 are also identical. u

The current amplifier 50 includes a potentiometer 200, 'the tap of which is electrically connected to the base of a transistor 202 and the input terminal 48. One end of the potentiometer 200 is connected through a resistor 204 to B- and the other end of the potentiometer 280 is connected through a resistor 206 to B+. The collector of the transistor 202 is directly connected to B- and the emitter of the transistor 202 is connected to the base of a second transistor 208 and through a resistor 210 to B+. The emitter of the transistor 208 is connected to a source of zero potential, or ground, and the collector thereof is connected to the output terminal 52 of the current amplifier 50 and through a resistor 212 to B-. Connected to the input terminal 48 of the current amplirfier 50 is a capacitor 214, one plate of which is connected to ground. Connected to the output terminal 52 of the current amplifier 50 Vis a variable capacitor216,

one plate of which is connected to ground.

Connected to the output terminal 52 of the current amplifier 50 is the single-shot multi-vibrator 78 comprising a transistor 218 having a base which is connected to the output terminal 40 through a resistor 220 and which is also connected to B+ through a resistor 222. The emitter of the transistor 218 is grounded andthe collector is connected to B- through a resistor 224. Also connected to the collector` of the transistor 218 through a capacitor 226 and a resistor 228 is the base of a transistor 230, which said base is also connected to B- through a resistor 232 in series with a potentiometer 234 having a tap which is also connected to B-. The emitter of the transistor 230 is connected to ground and the collector is connected to B- through a resistor 236 to ground through a capacitor 238, and to the base of the transistor 218 through a resistor 240.

The current amplifier 80 comprises a transistor 242, the base of which is connected to the collector of the transistor 230 through a resistor 244 and to B+ through a resistor 246. The emitter of the transistor 242 is grounded and the collector of the transistor 242 is connected to B- `throughtwo resistors, 248, 250, connected to each other in series. l

Connected to .the common juncture of the

resistors

248, 250 is the base of a transistor 252, the emitter of which is directly connected to B- and the collector of which is connected to the base of a second transistor 254 through a resistor 256. The base of kthe transistor 254 is also connected to B+ through a resistor 258. The emitter of the transistori254 is connected directly to ground, and the collector of the transistor 254 is connectedthrough the indicator light 84 to one terminal of the secondary coil 260 of a step-down transformer 262, the other terminal of the secondary coil 260 being con-V nected to ground, for purposes presently more fully to appear.

The

unilateral isolators

56, 72, comprise two diodes 300, 382, having a common anode connection 304 in the manner shown in FIGURE 2. Connected to the common anode connection 304 is the bell ringing circuit 86 which, save for the substitution of the bell 96 for the indicator light, 68, is identical in structure and operation to the indicator light igniting network 60. v

Connected to the common connection of the anodes of the

diodes

300, 302, is the single-shot multi-vibrator network 88 comprising a transistor 318 having a base whichv isv connected to the anode common connection through a resistor 320 and which is also connected to B+ through a resistor 322. The'emitter ofthe transistor 318 is grounded and the collector is connected to B- through a resistor 324. Also connected to the collector of the transistor 318 through a capacitor 326 and a resistor 328 is the base of a transistor 330, which said base is also connected to B- through a resistor 332 in series with a potentiometer 334 having a tap which is also connected to B-. The emitter of the transistor 330 is connected to ground and the collector is connected to B- through a resistor 336 to ground through a capacitor 338, and to the base of the transistor 318 through a resistor 340.

The current amplifier 90 comprises a transistor 342, the base of which is connected to the collector of the transistor 330 through a resistor 344 and to B+ through a resistor 346. The emitter of the transistor 342 is grounded and the collector of the transistor 342 is connected to B- through two resistors, 348, 350, connected to each other in series.

Connected to the common juncture of the resistors 348, 3511, is the base of a transistor 352, the emitter of which is directly connected to B- and the` collector of which is connected to the base of a second transistor 354 through a resistor 356. The base of the transistor 354is also connected to B+ through a resistor 358. The emitter of the transistor 354 is connected directly to ground, and the collector of the transistor 354 is connected through the bell 36 to one terminal of the secondary coil 360 of a step-down transformer 362, the other terminal of the secondary coil V360 being connected to ground, for purposes presently more fullyy to appear.

By way'of illustration, and not of limitation, the following chart discloses component magnitudes which we have found yields an acceptable foul detecting system:

Table A Resistors: Y Magnitude (ohms) 104, 204 1.2 meg. 106, 206 1.2 meg. 110, 210 22K. 112, 212 6.8K. 120, 220, 320 6.8K. 122, 222, 322 27K. 124, 224, 324 560. 128, 228, 328 1K. 132, 232,332 22K. 136, 236, 336 1.5K. 140, 240, 340 10K. 144, 244, 344 10K. 146, 246, 346 27K. 148, 248, 348 1.5K. 150, 250, 350 6.8K. 156, 256, 356 150. 158, 258, 358 1K.

Potentiometers z Y Ma gnitudc 100, 208 -O-l megohm. 134, 234, 334 -'010K.

ransistors: TYP@ 102, 202 2N 414. 108, 208 2N 414. 118, 218, 318 2N 414. 130, 230, 330 2N 414. 142, 242, 342 2N 414. 152, 252, 352 2N 414. 154, 254,354' 2N 277.

Capacitors: j

114, 214 .

O3 rnicrof.l

116, 216 5-15 microf. 126, 226 500 microf. 326 r microf. 138, 238, 338 f 10 microf.

Transformers:

162, 262, 362 Primary 117 `V., Secondary, 12 v., Y'oltages:

B+ to ground 6 v.

B- to ground -6 v It should be here noted that the current amplifiers: 38, 50, are each identical, one to the other; the single-shot multi-vibrator networks 62, 78, and 88 are each identical, one tothe other; the

current amplifiers

64, 80, and 90, are each identical one tothe other; the

electronic switches

66, 82, and 92, are each identical one to the other; and the indicator lights 68, and 841 and the bell 94 are each respectively connected to the

switches

66, 82, and 92, and the secondary coils 1.60, 260, and 360, of the

transformers

162, 262, 362'. l In operation, current always flows from B+' to B- through the resistor 106,r the potentiometer 100, and the resistor `104; in addition, the current also flows from BH- to B- through the resistors 122, 120, and 112; furthermore, current always ows from B+ to B- through the

resistors

122, 140, and 136; also, current flows from B+ to B-` through the resistors 146, 144, and 136.

The magnitudes of the resistors 104 and 106 and the potentiometer 100 are selected so that the transistor 102 will always be in conduction. With the light beam R always striking the photocell 30, current will be supplied to, the base of the transistor 102` from the photocell 30, and, as long as that beam R is being received by the photocell 30, the voltage at the emitter of the transistor 102 and the base of the transistor 108 is at its least positive value. With the base of the transistor 108 at its least positive value, the transistor 108 is placedin a state 'of conduction, thereby increasing the voltage drop across resistor 112 and reducing the amount of current that flows through the resistors 122 and 120. With the current througlrthe resistor 122 reduced, the voltage at the base of the transistor 118 becomes positive, the transistor 118 becomes cutoff, and the transistor 130 is biased to saturation through the potentiometer 134 and the resistor 132.

With the transistor-.130 in the saturated condition, the voltagey at the collector of the transistor 130 is at its most positive voltage, andthe currentwhich flows from Bei-to B through the resistors 146 and 144, is substantially reduced, whereby placing the voltage at the base of the transistor 142 at its most positive value, cutting off Vthe transistor 142.

With the transistor 142 in' the cutoff condition, no y current flows through the resistors 148, 150, and the transistor 152 is also biased to thev cutoff condition.

Similarly, with the transistor 152 in the cutoff condition,

substantially no current, flows through the transistor 154; "The capacitor 114 filters random noise from the output of the photocell 30 and prevents such noise from interfering with circuit operation. Similarly, the capacitor 138 is used to prevent random noise from triggering the single-shot multi-vobrator, particularly noise from* the B side of the power supply. The function of the=vari able capacitor 116 will be discussed in the succeeding paragraphs. f V- Y When the beam R is broken, either by the passage of a bowling ball or the foot of a bowler therethrough, and not received by the photocell 30, the voltage at the base of the transistor 102 is `made more positive and simultaneously the voltage at the emitter of the transistor 102 and the base of the transistor 108 is also made'more positive. condition and the voltage at the collectorof the transistor 108 becomesk substantially more negative due tothe substantial reductionvin current flow through the resistor 112.

determina'ole period of timeafter the beam R has been The vtransistor lflfthereby' goes into cutoff During theoperation of the transistor 108, the variable broken, ,which said period of time may beyarcd by varying the-magnitude of the capacitor 116; 'With the.,k magnitudes as disclosed on Table Athe charge time for` the capacitor 116 is made substantially longer than the collector of the transistor 108 decrease (become more` negative) only when the beam R is broken `by something that is substantially longer in time duration than the passage of a bowling ball therethrough.

Because the resistors 1.12 and 120 are each chosen to be substantially less in magnitude than the'resistor 122,l

the reduction in collector voltage of the transistor -108 will cause the voltage at the base of the transistor 118 to become negative, thereby causing the transistor 118 to go into conduction. Prior to conduction of the transistor 118, the capacitor 126 will have developedV a` charge. equal to thevoltage magnitude of B- with the platethat is connected to the collector of transistor 118 being the negative of the two plates. When the transistor 118 switches to the conducting state, its positive going collector voltage is coupled through capacitor 126 and resistor 128 to the base of transistor 130, cutting off the operation of transistor`130. In the manner conventional to single-shot multi-vibrators, the transistor 130 willy remain in the cutoff state for the period of time required for the capacitor 126 to discharge through the

resistors

128, 132, and the potentiometer 134, and the transistor 118 which'periodof time depends upon the magnitude of the capacitor 126 and the

resistors

128, 132, and the potentiometer 134, and not upon the period of time that the beamR has been broken. Therefore, once the beam Ris broken for asufficient length of time for the collector voltage of the transistor 108 to be substantially reduced,

the remainder of the circuit operation will not be affected for a finite period of time, notwithstanding that the beam R is reincident on the photocell 30.

As the ycapacitor 126 discharges through the

resistors

128 and 132, and the potentiometer 134, the voltage at the base of the transistor 130 becomes more negative with respect to the emitter thereof, and the amount of current that flows through the transistor 130 again begins to increase to the point of saturation. Negative voltage is transferred back to the base of the'transistor, 118 from the collector of the transistor 130 through the resistorv and holds the-transistor 118 in the conducting state until the transistor 130 reapproaches, saturation.

However, during the period of time when the voltage at the collector ofthe transistor 130 is at its most negative values, the base of the transistor 142 achieves a sufficiently negative value to cause the transistor 142 to go into conduction, and the transistor 142 remains in conductionuntil the` current whichv flows through the resistor l136 from thetransistor 130 achieves a sufficient magnitude to bring the voltage at the base of the transistor 142 to zero or positive. While the transistor 142 is in conduction,the base of the transistor v152 is biased into conduction bythe current flowing through the resistors 148, 150, from the `transistor 142. The conduction of the transistor 152 causes the -base ofthe'transistor 154 to go negative involtage and thereby causes the conductionv of the transistor 154. The transistor 154 stays in conduction only so long as the transistors 118, 142, and 152 conduct. j This period of conduction required inbowling alleys is nominally 12 seconds `,selectively 'determined by the adjustment `of the kvoltage tap on. the potentiometer 134, which adjusts the periodv of time required for `Vthe capacitor 126 to discharge, as previously explained.

As the` transistor 154 is vbrought into conduction, it

will supplywhatever Vcurrent is lrequired toprevent its f collector vfrom attaining ak negative voltage, thus current Y will flowv from the transistor 154 throughthe indicator light: 68 and the secondary 160r ofthe transformer 162 during each negative cycle of'voltage on the secondary o 160, and no current will flow when the voltage on the secondary 166 is positive with respect to ground.

The components numbered 2th? through 262 inclusive are respectively identical in operation to the components i) through 162 inclusive, with the exception that the components numbered 260 through 262 inclusive respond to the receiving and the breaking of a beam of light R transmitted by the beam projector 26 above the foul line 22 on the lane 12 and received by the photocell 42 in the rail 13. The breaking and receiving of the beam R by the photocell 42 will cause the componentsV numbered 260 through 262 inclusive to function identically as their correspondingly numbered components, previously described for the lane 16. Thus, normally when the beam R is received by the photocell 42, the transistors 262, 203, and 231), will be in conduction. When the beam R is broken for a period of time sufficiently long for the variable capacitor 216 to charge through the resistor 212, the transistor 218 will go into conduction, the capac-r itor 226 will charge, the transistor 236 will tend towards cutoif, the

transistors

242, and 252, will go into conduction, and the transistor 254 will go into conduction during negative half-cycles of voltage across the secondary 2611 of the transformer 262. 1t should be here noted that the

diodes

300, 302, prevent a decrease in voltage at one of the

output terminals

42, 54, from affecting the voltage at the other terminal.

in operation, the bell ringing circuit 36 functions almost identically to the indicating light networks 60, '76. When both of the beams R, R', are being received respectively by the

photocells

30, 42, current llows from B+ to B along each of the following courses through

resistor

322, 320, diode 300 and resistor 112 and through

resistor

322, 326, diode 302 and resistor 212. As long as `the beams R, R', are undisturbed, the operation of the components numbered 318 through 362 inclusive is identical with the operation of the components numbered 118 through 162 inclusive and the components numbered 218 through 262 inclusive. With both of the beams R, R', on both of lanes 10, 12, being unbroken, the transistor 318 is held in cut-off condition, the transistor 330 has been biased to saturation through the resistor 332 and the potentiometer 334, the transistor 342 is biased to cut-off as the transistor 142 and the

transistors

352, 354 are also inout-off condition as are the transistors 152, 154, respectively. In this condition, no current flows from the Vtransistor 354 through the conventional bell 94, notwithstanding the presence of the voltage on the secondary 369 of the step-down transformer 362.

When either of the light rays R, R, are broken by the passage of a bowlers foot through said beam, depending on which one is broken the transistor 10S, or 208, will be cut-off and the voltage at the collector of the particular transistor 108, 208, will decrease. This decrease in voltage will cause the current through the particular diode 31N), 302, and through the

resistors

322, 326, from B-lto decrease, increasing the voltage at the base of the transistor 318 and placing the transistor 318 into operation, which in turn starts the operation of the single-shot multivibrator 88. Once the operation of the single-shot multivibrator S8 commences, the components numbered 318 through 362 inclusive operate identically with the components numbered 118 through 162 inclusive andthe components numbered 21S through 262 inclusive when they are in operation. It should be observed that the ca- 108 will haveV no elect whatsoever on the single-shotV multivibrator 7S and similarly, operation of the transistor 20S will have no effect whatsoever on the operation of the single-shot multi-vibrator network 62. However, operation of either of the transistors 10S, 208, will cause the indicator light igniting network associating with that particular transistor tooperate and will simultaneously cause the operation of the bell ringing circuit 36 in parallel therewith.

When the transistor 354 goes into operation and establishes a continuous circuit through the bell 94 andthe secondary of the transistor 362 to ground, the transistor 354 behaves in a manner identical to the transistors 154 and 254 when they are in operation in that the transistor 354 will function in such manner as to prevent its collector from going negative. Thus during the negative cycles of the voltage across the secondary 360 of the transformer 362, the transistor 354 will supply substantial current through the bell 94 and will maintain' the voltage drop across the bell 94 to a magnitude suti'icient to keep the collector of the transistor 354 always positive. This unique and novel method of supplying a power to a bell and an indicator light from a transistor has eliminated the need for large current supply packs and large transistors, and enables power to be furnisehd using a simple transformer in combination with a transistor.

lt should be here noted that in most bowling alleys it is normal for the bell to ring for a period of 3 seconds and the lights to remain on for a period of l2 seconds, thus when the bell indicates that a foul has been committed on one of two alleys, the bowlers have an additional 9 seconds to determine on which alley the foul was committed. The period of time' for operation of the bells 94 and the

lights

68, 84, may be respectively adjusted by adjusting the setting of the tap Von potentiometers 334, 134, and 234, respectively. In addition, the taps on the potentiometers 100, 200, are eective means of providing an ambient light adjustment to compensate for varying amounts and quantities of light present on the

photocells

30, 42, respectively. l

If it is desired that the system be comprised entirely of solid state devices, a solar cell may be substituted for the

photocells

30, 42, in the conventional manner, and a transistorized audio oscillator coupled to a speaker may be substituted for the bell 94.

It should be understood that changes, alterations and modifications in the form, construction, arrangement and combination of parts of the amusement may be made and substituted for those herein shown and described without departing from the major and principle of my invention. For example, although we have disclosed our invention using p-n-p type function transistors for all Ytransistors shown with the exception of transistors 152,

252, and 352, which are n-p-n transistors, n-p-n transistors may be substituted for the p-n-p transistors and p-n-p transistors may be substituted for the n-p-n transistors in the conventional manner.

Having thus described our invention what we claim and desire to secure by Letters Patent is stated in the following claims:

1. A foul detecting and indicating device for use with a bowling lane including a foul line and dened by spaced parallel rails on opposing sides thereof, Vsaid device comprising a beam projector operatively mounted on one of said rails Vand adapted for projecting a beam of light, beam receiving means operatively mounted in the other rail for supplying a signal when a beam of light is received' from the beam projector, said beam projector and beam receiving means being in alignment with said foul line, amplifying means adapted for receiving the signal from the beam receiving means andV amplifying said signal, triggering means for supplying an actuating signal when themagnitude of the amplified signal is substantially reduced for more than apredetermined period of time,

A and output means including a transistor which is placed into saturated conduction by the operation of the triggering means, a transformer having one winding operatively connected to a source of alternating current power and a second winding connected in series with the terminals Vof the transistor through which the saturated current ows during conduction, and indicator means operatively connected in series with said second winding and said transistor terminals.

2. A foul detecting and indicating device comprising means for projecting a beam across the foul line of a bowling lane, means for receiving said beam, a transistor operatively connected to a source of power and having a base and a collector and an emitter, a transformer having a primary winding and a secondary winding, indicating means adapted for operating upon application of electrical power thereto, said indicating means and secondary winding being connected in series to the emitter and collector, said primary winding being operatively connected to a source of alternating current electrical power, and triggering means connected to said beam receiving means 10 for causing the transistor to go into conduction when a bowler commits a foul by breaking the beam.

3. The device of claim 2 in which the triggering means includes means for retaining the said transistor in conduction for a predetermined period of time.

References Cited by the Examiner UNITED STATES PATENTS 2,099,764 11/ 37 Touceda.

2,455,909 12/48 Smith 273-50 2,492,182 12/49 Robinson.

2,664,290 12/53 Swift 273-50 2,683,602 7/54 Dumas et al 273-50 2,782,406 2/57 Krakora.

2,954,489 9/60 Brueggeman et al. 307-117 2,975,293 3/61 Kruse et al 250-214 X 2,980,425 4/61 Zaander 273-43 3,029,354 4/ 62 Watkins 307-117 20 DELBERT B. LOWE, Primary Examiner.

Claims

2. A FOUL DETECTING AND INDICATING DEVICE COMPRISING MEANS FOR PROJECTING A BEAM ACROSS THE FOUL LINE OF A BOWLING LANE, MEANS FOR RECEIVING SAID BEAM, A TRANSISTOR OPERATIVELY CONNECTED TO A SOURCE OF POWER AND HAVING A BASE AND A COLLECTOR AND AN EMITTER, A TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING, INDICATING MEANS ADAPTED FOR OPERATING UPON APPLICATION OF ELECTRICAL POWER THERETO, SAID INDICATING MEANS AND SECONDARY