Reverse signal alarm system

Claim 2

An encapsulated solid state circuitry for a reverse signal alarm for a vehicle or the like which comprises: a first flipflop circuit including a pair of transistors, each having a base, emitter and collector, the base of each of said transistors connected via a feed-back condensor to the collector of the other transistor and including resistances whereby the period of first flip-flop circuit is about one second; a second flip-flop circuit including a further pair of transistors each having a base, emitter and collector, the base of each of said further transistors connected via a feed-back condenser to the collector of the other said further transistors, and including further resistors whereby the period of said flip-flop circuit is about 900 - 1200 cycles per second; said pair and further pair of transistors each having the same industrial rating whereby they are interchangeable in the circuitry diode means only in a circuit connecting the emitter of one of said transistors in said first flip-flop circuit with a base of a further transistor in said second flip-flop circuit whereby said second flip-flop circuit is inoperative for about one-half of the cycle of said first flip-flop circuit, speaker means including a circuit having a control transistor in series therewith, said control transistor amplifying current by a factor of one hundred or better and having its base connected to the emitter of a said further transistor in said second flip-flop circuit whereby said speaker operates at about 900 - 1200 cycles per second for successive constant periods of about one-half second; said circuit of said speaker means, said first flip-flop circuit, and said second flip-flop circuit being connected in parallel for connection to a direct current source, switch means connecting said current source into said circuitry whereby when said switch means is opened voltage is not applied in said circuitry, means in the vehicle on the like sensing that it is in operative condition to proceed in a reverse direction for closing said switch means, and further diode means included in series in said circuitry between the connection of said circuits and said switch means connection of said direct current serving to prevent application of reverse polarity to said circuits whereby the system is inoperable if reverse polarity is applied thereto, the circuitry being entirely encapsulated except leads to said current source.

Claim 3

Circuitry for a reverse alarm in accordance with claim 1 wherein said further diode means is in series with the negative connection to said direct current.

Claim 4

An encapsulated solid state circuitry in accordance with claim 1 wherein said circuitry is entirely ungrounded except one of said leads, only two of said leads being provided from said encapsulated circuitry.

Claim 5

A self-contained circuit without an external connection except for only a pair of elEctrical connections to a direct current source which provides electrical current in the range of about 6 - 36 volts for a reverse signal alarm for vehicles or the like which comprises: a first electrical conductor leading from one of said connections; a second electrical conductor leading from the other of said connections; and the following components connected in parallel across said first and second conductors: voltage limiting means limiting the voltage across said conductors to not more than about 8 1/2 volts; a first oscillator circuit; a second oscillator circuit; and a horn circuit; wherein the voltage limiting means comprises a first transistor connected in series in said first conductor and a zener diode connecting the base of said first transistor to said second conductor whereby the voltage difference across said first and said second conductors is limited to a predetermined maximum; the second oscillator circuit having a frequency substantially greater than that of the switching action of said first oscillator circuit, said first and second oscillator circuits each comprising a pair of transistors and a pair of feed-back capacitors which are arranged so that the output of one of said transistor pair is coupled to the input of the other of said transistor pair through one of said feed-back capacitors and the output of the other said transistor is coupled through the other feed-back capacitor to the input of said one transistor of said transistor pair, the transistors of said transistor pairs each having the same industrial rating whereby they are interchangeable in said oscillator circuits; said horn circuit including an inductance actuated speaker and a power transistor in series therewith, said power transistor having a current gain of one hundred or more; first diode means being connected in series in one of said conductors after its connection and prior to said components which is adapted to prevent the application of reverse current through said components; second diode means only directly coupling a transistor in said first oscillator circuit to a selected transistor in said second oscillator circuit whereby said second oscillator circuit is interrupted at substantially uniform periods of time each less than about one second in response to each said switching action of said first oscillator circuit, the selected transistor being coupled to the input of said power transistor whereby said inductance is actuated at the frequency of said second oscillator circuit with the interruptions corresponding to the switching actions of said first oscillator circuit.

Claim 6

A self-contained circuit without an external connection except for only a pair of elEctrical connections to a direct current source which provides electrical current in the range of about 6 - 36 volts for a reverse signal alarm for vehicles or the like which comprises: a first electrical conductor leading from one of said connections; a second electrical conductor leading from the other of said connections; and the following components connected in parallel across said first and second conductors: voltage limiting means limiting the voltage across said conductors to not more than about 8 1/2 volts; a first oscillator circuit; a second oscillator circuit; and a horn circuit; wherein the voltage limiting means comprises a first transistor connected in series in said first conductor and a zener diode connecting the base of said first transistor to said second conductor whereby the voltage difference across said first and said second conductors is limited to a predetermined maximum; the second oscillator circuit having a frequency substantially greater than that of the switching action of said first oscillator circuit, said first and second oscillator circuits each comprising a pair of transistors and a pair of feed-back capacitors which are arranged so that the output of one of said transistor pair is coupled to the input of the other of said transistor pair through one of said feed-back capacitors and the output of the other said transistor is coupled through the other feed-back capacitor to the input of said one transistor of said transistor pair, the transistors of said transistor pairs each having the same industrial rating whereby they are interchangeable in said oscillator circuits; said horn circuit including an inductance actuated speaker and a power transistor in series therewith, said power transistor having a current gain of one hundred or more; first diode means being connected in series in one of said conductors after its connection and prior to said components which is adapted to prevent the application of reverse current through said components; second diode means only directly coupling a transistor in said first oscillator circuit to a selected transistor in said second oscillator circuit whereby said second oscillator circuit is interrupted at substantially uniform periods of time each less than about one second in response to each said switching action of said first oscillator circuit, the selected transistor being coupled to the input of said power transistor whereby said inductance is actuated at the frequency of said second oscillator circuit with the interruptions corresponding to the switching actions of said first oscillator circuit.

Claim 7

A self-contained circuit in accordance with claim 4 wherein the switching action of said transistor pair of said first oscillating circuit is about 0.5 seconds.

Claim 8

A self-contained circuit in accordance with claim 5 wherein the frequency of said second oscillator circuit is in the range of 900 - 1200 cycles per second.

Claim 9

A self-contained circuit in accordance with claim 4 wherein all of said components except the output connections and said speaker are encapsulated in non-conductive plastic material.

Claim 10

A self-contained circuit in accordance with claim 4 wherein said first conductor is adapted for connection to the positive terminal of a direct current electrical source.

Claim 11

A self-contained circuit in accordance with claim 4 wherein said predetermined maximum voltage difference is about 8.5 volts.

Claim 12

A self-contained circuit in accordance with claim 9 wherein the decibels produced by said speaker in operation are in a range of 101 - 111.