ELECTRIC CIRCUIT FOR AUTOMATICALLY IGNITING PARKING LAMPS AT DUSK
United States Patent 3694690
The present invention discloses an electric circuit for automatically igniting parking lamps at dusk which comprises a light detecting circuit composed of one or more photoconductive elements, and one or more relays connected to the photoconductive element and having a plurality of contacts connected to a below mentioned parking lamp circuit; the parking lamp circuit adapted to be selectively operated through operation of the relay of said light detecting circuit thereby to ignite one or all of parking lamps; and a switching circuit composed of a relay connected between an ignition switch arranged for closing and opening a power source and the light detecting circuit and having a plurality of contacts breaking or completing a winker circuit and the light detecting circuit according to operation of said ignition switch. The electric circuit can ignite the left and right parking lamps simultaneously and automatically as it becomes dark, hence the sign of parking is more effectively known by other car. This will contribute to more complete prevention of traffic accidents.
US Patent References:
Time delay and daylight inhibiting means for controlling automotive lighting systems
Miller - September 1966 - 3274434
Light sensitive unit
Scanlon - April 1963 - 3088051
Photo-electric relay apparatus
Watts - April 1958 - 2831981
CLOCK AND LIGHT-SENSITIVE LIGHT CONTROL SYSTEM FOR MOTOR VEHICLES
Keighly, Jr. - July 1971 - 3591825
Light sensitive control system for automobile lighting circuits
Collins - October 1967 - 3349281
Time delay and daylight inhibiting means for controlling automotive lighting systems
Miller - September 1966 - 3274434
Light sensitive unit
Scanlon - April 1963 - 3088051
Photo-electric relay apparatus
Watts - April 1958 - 2831981
CLOCK AND LIGHT-SENSITIVE LIGHT CONTROL SYSTEM FOR MOTOR VEHICLES
Keighly, Jr. - July 1971 - 3591825
Light sensitive control system for automobile lighting circuits
Collins - October 1967 - 3349281
Inventors:
Shimizu, Tetsuji (Nagoya, JA)
Yoshida, Takaomi (Nagoya, JA)
Otake, Sugako (Kariya, JA)
Sumida, Hajime (Nagoya, JA)
Ueno, Shinichi (Nagoya, JA)
Yoshida, Takaomi (Nagoya, JA)
Otake, Sugako (Kariya, JA)
Sumida, Hajime (Nagoya, JA)
Ueno, Shinichi (Nagoya, JA)
Application Number:
05/007499
Publication Date:
09/26/1972
Filing Date:
02/02/1970
View Patent Images:
Export Citation:
Assignee:
Kabushiki Kaisha Tokai Rika Denki Seisakusho (Nishi-Kasugai-gun Aichi Prefecture, JA)
Primary Class:
Other Classes:
315/83, 315/149, 315/159
International Classes:
B60Q1/14
Field of Search:
315/77,82,200.1,83,360,149,159 250/206,211 340/322
US Patent References:
| 3423633 | HEAD LAMP SYSTEM WITH PHOTOELECTRIC SWITCHING AND TIME DELAY EXTINGUISHING | January 1969 | Kawai |
Primary Examiner:
Saalbach, Herman Karl
Assistant Examiner:
Baraff C.
Claims:
What is claimed is
1. In an electric circuit applicable to a vehicle or the like for enhancing the visibility thereof when inoperative during dusk and dark by igniting parking lamps or the like thereof and wherein the vehicle or the like includes a power source and an ignition switch actuable for energizing electrical circuitry of the vehicle from such power source, the combination comprising:
2. In an electric circuit applicable to a vehicle or the like for enhancing the visibility thereof when inoperative and during dusk and dark by igniting parking lamps or the like thereof and wherein the vehicle or the like includes a power source and an ignition switch actuable for energizing electrical circuitry of the vehicle from such power source, the combination comprising:
3. The electrical circuit of claim 2 including means connecting said contact means of said further relay, said further switch and said first relay in a first series loop with said power source and means connecting said ignition switch and further relay in a further series loop with said power source and paralleling said first mentioned series loop, said photoconductive element shunting a portion of said first series loop and responding to a high light level condition for preventing conduction through said first series loop of current sufficient to actuate said first relay.
4. The electrical circuit of claim 3 in which said first series loop includes a transistor switch in series therewith, said photoconductive element being connected across a portion of said transistor for preventing conduction therethrough under high light level conditions.
5. The electrical circuit of claim 3 in which said photoconductive element is connected across a portion of said first series loop at least including said further switch and first relay for shunting current flow from said power source therearound under high light level conditions.
6. The electrical circuit of claim 2 including flasher circuitry, in which said further relay has further contact means for connecting said flasher circuitry to said further switch when ignition switch is actuated to enable lamps on alternative sides of the vehicle to be flashed in response to appropriate actuation of said further switch and for disconnecting said flasher circuitry from said further switch upon the actuation of said ignition switch.
7. The electrical circuit of claim 1 in which the vehicle includes a flasher circuit for repetetively flashing lamps of the vehicle and means including said contact means for connecting said flasher circuit to said first means when said ignition switch is actuated for allowing said flashing of lamps but disconnecting said flasher circuit from said first means when said ignition switch is deactuated.
8. An electric circuit connectable to a power source, a parking lamp circuit and a winker circuit, for automatically igniting parking lamps of a vehicle of the like at dusk which comprises:
9. The electrical circuit of claim 8 in which said light detecting circuit further includes means connecting said ignition switch across said photoconductive element for shunting the latter when said ignition switch is closed, means connecting said photoconductive element between said power source and said transistor means in responsive to an open condition of said ignition switch and a low light level condition for causing said transistor means to energize said further relay, said first mentioned relay and ignition switch being connected in series across said power source whereby opening of said ignition switch de-energizes said first mentioned relay.
10. The electrical circuit of claim 8 in which said parking lamp circuit includes said parking lamps, said first mentioned relay having a plurality of contacts connected between said lamps and said winker switch, said parking lamp switch having contact means for joining ones of said lamps to said power source through contacts of said further relay, said further relay having contacts selectable upon energization of said further relay for alternative connection of one of said lamps to said power source through contacts of said first mentioned relay, said winker switch, and contacts of said further relay.
1. In an electric circuit applicable to a vehicle or the like for enhancing the visibility thereof when inoperative during dusk and dark by igniting parking lamps or the like thereof and wherein the vehicle or the like includes a power source and an ignition switch actuable for energizing electrical circuitry of the vehicle from such power source, the combination comprising:
2. In an electric circuit applicable to a vehicle or the like for enhancing the visibility thereof when inoperative and during dusk and dark by igniting parking lamps or the like thereof and wherein the vehicle or the like includes a power source and an ignition switch actuable for energizing electrical circuitry of the vehicle from such power source, the combination comprising:
3. The electrical circuit of claim 2 including means connecting said contact means of said further relay, said further switch and said first relay in a first series loop with said power source and means connecting said ignition switch and further relay in a further series loop with said power source and paralleling said first mentioned series loop, said photoconductive element shunting a portion of said first series loop and responding to a high light level condition for preventing conduction through said first series loop of current sufficient to actuate said first relay.
4. The electrical circuit of claim 3 in which said first series loop includes a transistor switch in series therewith, said photoconductive element being connected across a portion of said transistor for preventing conduction therethrough under high light level conditions.
5. The electrical circuit of claim 3 in which said photoconductive element is connected across a portion of said first series loop at least including said further switch and first relay for shunting current flow from said power source therearound under high light level conditions.
6. The electrical circuit of claim 2 including flasher circuitry, in which said further relay has further contact means for connecting said flasher circuitry to said further switch when ignition switch is actuated to enable lamps on alternative sides of the vehicle to be flashed in response to appropriate actuation of said further switch and for disconnecting said flasher circuitry from said further switch upon the actuation of said ignition switch.
7. The electrical circuit of claim 1 in which the vehicle includes a flasher circuit for repetetively flashing lamps of the vehicle and means including said contact means for connecting said flasher circuit to said first means when said ignition switch is actuated for allowing said flashing of lamps but disconnecting said flasher circuit from said first means when said ignition switch is deactuated.
8. An electric circuit connectable to a power source, a parking lamp circuit and a winker circuit, for automatically igniting parking lamps of a vehicle of the like at dusk which comprises:
9. The electrical circuit of claim 8 in which said light detecting circuit further includes means connecting said ignition switch across said photoconductive element for shunting the latter when said ignition switch is closed, means connecting said photoconductive element between said power source and said transistor means in responsive to an open condition of said ignition switch and a low light level condition for causing said transistor means to energize said further relay, said first mentioned relay and ignition switch being connected in series across said power source whereby opening of said ignition switch de-energizes said first mentioned relay.
10. The electrical circuit of claim 8 in which said parking lamp circuit includes said parking lamps, said first mentioned relay having a plurality of contacts connected between said lamps and said winker switch, said parking lamp switch having contact means for joining ones of said lamps to said power source through contacts of said further relay, said further relay having contacts selectable upon energization of said further relay for alternative connection of one of said lamps to said power source through contacts of said first mentioned relay, said winker switch, and contacts of said further relay.
Description:
This invention relates to an electric circuit for automatically igniting parking lamps of automobiles at dusk in which parking lamps, when a car is parked, are automatically lit as it becomes dark.
Prior electric circuits for automatically igniting parking lamps have been so designed that the parking signal lamp is ignited only on the side of the vehicle where a winker or flasher or turn signal switch is turned on. Stated illustratively, the winker switch is normally set to light a right parking lamp when a car is parked on the left side of a street or road and a winker switch is set to light a left lamp when a car is parked on the right side of a street. Accordingly, if one of the parking signal lamps is disconnected, both the lamps may fail to be lit, making prevention of accidents imperfect. Furthermore, it is necessary to provide an electric circuit specially for the purpose.
The present invention is made taking the abovementioned inconveniences into consideration and it is a primary object of this invention to provide an electric circuit for automatically lighting parking lamps of a car at dusk, in which, when it becomes dark, right and left parking lamps are independently lit in an automatic manner or both the lamps are simultaneously lit by preliminarily setting a knob.
Another object of the present invention is the provision of an extremely economical electric circuit for automatically lighting parking lamps of a car at dusk, which is equipped without changing operations of existing switches or circuits with which the vehicle is already equipped.
Another object of the present invention is the provision of an electric circuit for automatically igniting parking lamps of an automobile at dusk, in which the circuit is so adapted as to light a parking lamp on the side of the vehicle to which a switch is connected during parking, and when it becomes dark, and to make a third person know the parking-position of the car thus preventing accidents such as rear-end collisions.
Accordingly the present invention comprises an electric circuit for automatically igniting parking lamps at dusk which comprises a light detecting circuit composed of one or more photoconductive elements, and one or more relays connected to the photoconductive element and having a plurality of contacts connected to a belowmentioned parking lamp circuit; the parking lamp circuit adapted to be selectively operated through operation of the relay of said light detecting circuit thereby to ignite one or all of parking lamps; and a switching circuit composed of a relay connected between an ignition switch arranged for closing and opening a power source and the light detecting circuit and having a plurality of contacts breaking or completing a winker circuit and the light detecting circuit according to operation of said ignition switch.
A further subject of the invention lies in an electric circuit for automatically igniting parking lamps at dusk which comprises a switching circuit composed of an ignition switch for opening and closing a power source, and a relay connected to said ignition switch and operating a parking lamp circuit and a winker circuit according to the operation of said ignition switch; a light detecting circuit composed of a photoconductive element, a relay connected to said photoconductive element and operating through said photoconductive element when said ignition switch is opened, and transistors connected to said relay; and a parking lamp switch connected between the relay of said light detecting circuit and a lamp circuit, said parking lamp switch igniting one or all of parking lamps independently or under cooperation of said winker switch according to the operation of said relay of light detecting circuit.
The accompanying drawings show several embodiments of an electric circuit for automatically igniting parking lamps at dusk, wherein,
FIGS. 1 and 2 are connection diagrams of electric circuits in which a pair of relays are employed in a light detecting circuit section;
FIGS. 3 and 4 show connection diagrams of electric circuits in which a pair of relays and a transistor are employed in the light detecting circuit section;
FIG. 5 shows an electric circuit in which only a relay is connected to the light detecting circuit section and a parking lamp switch is connected to a parking lamp circuit.
Each example will be explained according to the accompanying drawings, wherein the same elements are represented by the same reference numerals. In FIGS. 1 to 4, the electric circuit for automatically igniting parking lamps at dusk is composed of three circuit sections, namely, a light detecting circuit section with a photoconductive element, a relay section which connects a power source to said light detecting section and has a switch to operate without troubles with existing parking and flasher circuits, and a lighting circuit for igniting any of parking lamps in response to the operation of said relay section. They will respectively be described in detail as follows.
A light detecting circuit section A (FIG. 1) comprises a photoconductive element P, for example, of cadmium sulphate (CdS), which converts a strength of light to a variation of electric current, affected by ambient light, a switch SW2, a left relay 2RL and a right relay 2RR connected respectively to a left fixed contact 2b and a right fixed contact 2c of said switch SW2. The movable contact 2a of said switch SW2 is normally kept in the neutral position. A protective resistor R1 is connected between a battery 5 and the photoconductive element P. When outer light reduces and the resistance of the photoconductive element P increases, the voltage at a connection point Q increases to impress current on the one of relays 2RR or 2RL to which the movable contact 2a is connected, thus operating an undermentioned parking lamp lighting circuit C. As mentioned later, a photoconductive element is preferred to be of little light resistance when a transistor Tr1 is not employed in the light detecting circuit section A.
The relay circuit section B includes an ignition switch SW1 connected between the battery 5 and a relay 1R and closed when an engine key is put in and turned as in the ordinary manner.
Accordingly the relay circuit section B operates depending upon whether a circuit is closed or opened between the terminals 1a and 1b of the ignition switch SW1 to make the electric circuit for automatically igniting parking lamps operate normally and set the circuits in use so as not to be influenced by this electric circuit. The above-mentioned relay 1R has three contacts a, b and c. The contact a controls connection of the power source 5 to the above-mentioned light detecting circuit section A and is normally opened when the power source is connected to the relay 1R of section B and contacts b and c coact to control energization or deenergization of coils 8a or 8b of a relay 8.
Ignition circuit section C is operated by the switch SW2 of the light detecting circuit section A to ignite right or left parking lamps including tail lamps.
Reference characters 9L and 9R indicate respectively a left and a right parking lamp section, the left parking lamp section 9L comprising a left parking lamp 10LL and a left tail lamp 11LL, and the right parking lamp section 9R including a right parking lamp 10LR and a right tail lamp 11LR. These lamps are connected to a group of contacts, d, e, f and g which are operated together according to energization or deenergization of the right and left relays 2RR and 2RL of said light detecting section. Of these contacts, movable contacts, d1, e1, f1, and g1 are normally retained in the positions shown in the drawings. The above description of FIG. 1 also applies to FIGS. 2-4.
A switch SW3 for parking and tail lamps is manually operable and has a fixed contact 3a connected to the terminal of the battery 5, a fixed contact 3b connected to parking lamps 10LR and 10LL, a fixed contact 3c connected to tail lamps 11LL and 11LR, and a movable contact 3d connected to a manually operable knob K. The operation of this switch SW3 is such that at the first downward motion of the knob K manually operated in the direction of arrow, the movable contact 3d is brought into contact with the fixed contact 3b connected to the parking lamps 10LL and 10LR, the fixed contact 3c connected to tail lamps 11LL, 11LR, and the fixed contact 3a connected to the power source 5, thereby simultaneously connecting these contacts. By another downward motion of the manually operated knob K in the arrow direction, the movable contact 3d is moved downwardly to detach from the fixed contact 3b, thereby connecting the fixed contact 3c with the fixed contact 3a connected to the power source to make a close circuit therebetween. Accordingly, if a driver manually operates the knob K downwardly, for example, at the first downwardly pulling operation of the knob by the driver, left and right parking lamps 10LL, 10LR and tail lamps 11LL, 11LR are simultaneously ignited, and at the subsequent pulling operation of the knob K in the direction of arrow by the driver, only the left and right tail lamps are turned on.
Though small differences due to the kind or the year of a car are seen in a flasher or a stop signal lamp circuit, they are included in the examples shown in FIGS. 1 to 4. In each drawing 13 indicates a flasher unit which is, in FIGS. 2 and 4, connected between the battery 5 and the terminal a2 and h2, respectively of the corresponding contact a which is actuated by the relay 1R. Flasher lamps 12LL and 12LR are connected to said flasher unit 13.
Furthermore, in FIGS. 3 and 4, the reference characters Tr1 indicates a transistor to the collector side of which the right and left relays 2RL and 2RR are connected and the prescribed photoconductive element P is connected between the emitter and the base of said transistor. In FIG. 2, 14 indicates a positive thermistor connected to protect the photoconductive element.
Said thermistor 14 is selected from those having such characteristics that its resistance at the normal temperature, 25° C, is equivalent to a light resistance of the photoconductive element P during day time and noticeably increases due to self-heating taking place when, in the day time, the resistance of said photoconductive element P is decreased to apply several volts of voltage to the thermister, thus serving to reduce the power consumption of the photoconductive element P, and that as it becomes dark, the resistance of said photoconductive element P increases to reduce the voltage to be impressed on this positive characteristic thermistor 14, so that the thermister 14, at this time, operates as a resistor having a value less than 100 Ω.
Referring to the above-mentioned circuits of FIGS. 1 - 4, the operations are explained as follows:
When the terminals 1a and 1b of the ignition switch SW1 are connected to each other by turning on the engine key in the usual manner, the relay 1R is operated to move respective contacts a, b and c to the positions as shown in the respective drawings.
In such a state, when the switch SW2 is operated to bring its movable contact 2a into contact with either the left fixed contact 2b or the right fixed contact 2c, the corresponding flasher lamp 12LL or 12LR flashes through the medium of the flasher unit 13.
Then, when a driver stops a car and takes off the engine key from the ignition switch SW1, the circuit is opened between the terminals 1a and 1b, and the selector relay 1R connected from said terminals is deenergized to move its contacts a, b and c to their other positions. Consequently, in FIGS. 1 and 3, the contact a is closed and the contacts b and c are opened, and in FIGS. 2 and 4, the movable contacts a1 and h1, respectively are switched to the terminals a3 and h3, respectively and the movable contacts b1 and c1 are switched to the terminals b3 and c3 from the terminals b2 and c2.
Then, as soon as the power source 5 is connected to the light detecting circuit section, power supply to the flasher circuit consisting of the flasher unit 13 and the flasher lamps 12LL and 12LR is stopped.
When it becomes dark and the resistance of the photoconductive element P increases, the voltage at the connection point Q increases to operate either the left relay 2RL or the right relay 2RR, to one of which the switch SW2 is preliminarily set. More particularly as to FIGS. 3 and 4, when it becomes dark and the resistance of the photoconductive element P increases, the bias voltage of the base of the transistor Tr1 increases in the forward direction and said transistor is turned on to operate the relay 2RL or 2RR to which the switch SW2 is turned.
Thus, when said relay 2RL or 2RR is operated, for example, when the right relay 2RR is operated, its movable contacts d1 and e1 are simultaneously turned to the fixed contacts d3 and e3 from the fixed contacts d2 and e2.
Accordingly the parking lamp 10LR and the tail lamp 11LR located on the right side lamp ignition circuit section 9R are lit by the power supplied from the battery 5 through the line L.
In such a case, the switch SW3 is manually operated to move its movable contact 3d into contact with the fixed contact 3b for the parking lamps or the fixed contact 3c for the tail lamps, the parking lamp 10LL or tail lamp 11LL of the left side ignition circuit section 9L is lit.
FIG. 5 shows a still further embodiment of the present invention, in which the light detecting circuit section includes only a relay and two transistors, said relay being actuated when one of said two transistors is rendered conductive, a switch for parking lamps is connected between said relay and the parking lamp circuit, said switch for parking lamps igniting any or all of parking lamps in cooperation with said relay and a winker switch.
Similarly to the above-described embodiments of FIGS. 1-4, the ignition switch SW1 of FIG. 5 has one terminal connected to the anode of the power source 5 and other terminal connected to a resistor R2, to a relay 3RL and to the flasher unit 13 for winkers through the fuse F1. Said ignition switch SW1, like the usual ignition switch, is opened or closed according to the withdrawal or insertion of a key. The relay 3RL and the flasher unit 13 are grounded. An output terminal of the flasher unit is connected to a fixed contact m3 of a relay 4RL connected to the light detecting circuit. A fixed contact m4 of the relay 4RL is connected to the power source 5 through the fuse F2. One terminal of resistor R2 is connected to the photoconductive element P of CdS and a base of an NPN transistor Tr2. Other terminal of said photoconductive element P is connected to the anode of power source 5. The collector of transistor Tr2 is connected to the anode of power source 5 through a resistor R3 and to a base of another NPN transistor Tr3. The collector of said transistor Tr3 is connected to the anode of power source 5 through the relay 4RL. Emitters of transistors Tr2 and Tr3 are grounded. The resistor R4 is connected between the base of transistor Tr3 and ground, for the purpose of biasing the transistor.
The relay 4RL has a plurality of fixed contacts and movable contacts, in which the fixed contact m2 is connected to fixed contacts 4b, 4e of a switch SW4 for parking lamps; the fixed contact m4 is connected to fixed contacts 4c, 4f of the switch SW4, and the fixed contact m1 remains opened. The movable contacts m5 and m6 of said relay 4RL are connected to a movable contact 5a of a winker switch SW5. Fixed contacts 5b and 5c of said winker switch SW5 are connected to movable contacts k3 and k6 of relay 3RL, respectively. Fixed contacts k1 and k4 of said relay 3RL are connected to left and right winker lamps 14LL and 14LR through respective diodes D for preventing the feedback of current, respectively. Fixed contacts k2 and k5 are directly connected to the left and right winker lamps 14LL and 14LR, respectively. The winkers and parking lamps are respectively grounded at one terminal.
Movable contacts 4h, 4g of said switch SW4 for parking lamps are connected to the left-side and right-side parking lamps 15LL and 15LR, respectively, while fixed contacts 4a and 4d remain opened.
Operation of the thus connected electric circuit will be described.
The drawing shows that the ignition switch SW1 is now kept in the closed position, and current flows to coils of relay 3RL from the power source 5, so that the movable contacts k3 and k6 of relay 3RL are retained in contact with the fixed contacts k2 and k5, respectively. If the winker switch SW5 is operated to turn its movable contact 5a to one of fixed contacts 5b and 5c, either winker lamp 14LR or 14LL is ignited through the flasher unit 13, thereby flashing one of winker lamps 14LR and 14LL.
If the key is withdrawn from the ignition switch SW1 at the time of parking and resultantly the ignition switch is turned open, current flows to the coil of relay 3RL through the CdS photoconductive element P and the resistor R2, so that the movable contacts k3 and K6 of relay 3RL are turned into contact with the fixed contacts k1 and k4, respectively. If the switch for parking lamps SW4 is operated to move the movable contacts 4h and 4g into contact with the fixed contacts 4f and 4c respectively, the parking lamps 15LL and 15LR are ignited through the fixed contact m4 of relay 4RL. In this case, the parking lamps can be ignited if the ignition switch SW1 remains closed. None of the parking lamps can be ignited if the movable contacts 4h, 4g are connected to fixed contacts other than the fixed contacts 4c and 4f.
As it becomes dark and the ambient light gradually decreases, the resistance of the CdS photoconductive element P increases and current flowing to the base of transistor Tr2 becomes reduced. Consequently, said transistor Tr2 is rendered nonconductive, while current flows to the transistor Tr3 through the resistor R3, so that said transistor Tr3 becomes conductive. When said transistor Tr3 becomes conductive, current flows to the relay 4RL, and its movable contacts m5 and m6 are brought into contact with the fixed contacts m2 and m4, respectively. In this connection, if the switch for parking lamps SW4 is turned to make the movable contacts 4g and 4h contact with the fixed contacts 4b and 4e, respectively, current from the power source 5 flows to the parking lamps 15LL and 15LR through the fixed contact m4, the movable contacts m6 and m5 and the fixed contact m2 of relay 4RL, thereby igniting the parking lamps 15LL and 15LR.
If the switch SW4 for parking lamps is turned to move its movable contacts 4g and 4h into contact with the fixed contacts 4a and 4d and the winker switch SW5 is operated to make its movable contact 5a contact with either of fixed contacts 5b or 5c, current flows to one of left and right parking lamps 15LL and 15LR through the fixed contact m4 and the movable contact m6 of the relay 4RL, thereby igniting one of parking lamps 15LL or 15LR. Where ignition of parking lamps is not required, for example, when an automobile is put in the garage or the parking place, the winker switch SW5 is set to maintain its movable contact 5a in the neutral position, so that none of parking lamps 15LL, 15LR are ignited.
In the light detecting circuit A including the photoconductive element P and transistors Tr2 and Tr3, the potential at the junction point between said photoconductive element P and the resistor R2 becomes equal to that of the power source while the ignition switch SW1 is maintained in the closed position, hence the relay 4RL is kept inoperative. Therefore, the switching or relay circuit section B is brought into the normal operation.
The transistors connected to the light detecting circuit A are here shown as of the NPN type, but it is fully contemplated that PNP transistors are employable in place of the NPN transistors.
A plurality of photoconductive elements P may be employed if a plurality of AND circuits including diodes are additionally connected to the light detecting circuit. In this case, the plurality of photoconductive elements P may be arranged in desired places on the car body, so that if the light of head lamps of a following or coming car influences upon any of photoconductive elements to render it inoperative, the other photoconductive elements will perform a normal operation.
Thus, the plurality of photoconductive elements will more effectively contribute to prevention of a traffic accident than a single photoconductive cell will. In other words, any of plurality of AND circuits will surely operate to ignite all or desired parking lamps, as far as one of plurality photoconductive elements is in operation.
In embodiment of FIG. 5, a single relay 4R1 is employed in the light detecting circuit, said relay being connected to a plurality of transistors. The resistance of photoconductive element P increases as the ambient light decreases at dusk, and thereby one of transistors becomes nonconductive while the other transistor is turned conductive, thereby operating the relay to turn its movable contacts from one position to the other. The parking lamp circuit in this embodiment includes the winker switch SW5 and the switch for parking lamps SW4 connected to a group of contacts of relay 4RL, in which the switch for parking lamps SW4 conducts independently or under cooperation of the winker switch SW5 the ignition of all or any of parking lamps. In such circuit construction, if the winker switch and the switch for parking lamps are set to a position for igniting the parking lamps when a driver leaves the car, any of left and right parking lamps will be automatically ignited in the twilight hours, so that parking of the automobile is perceived by other cars.
The electric circuit for automatically igniting parking lamps at dusk of the present invention has many advantages that the circuit is simple in its construction and operates with reliability, which will be of great help to prevent a car from accidents such as a rear-end collision, and that the circuit of the present invention can be also easily incorporated into any existing circuits of any kinds of automobiles, without replacing their winker circuits or switch means and without changing their operation, which will attribute to economy and usability.
Prior electric circuits for automatically igniting parking lamps have been so designed that the parking signal lamp is ignited only on the side of the vehicle where a winker or flasher or turn signal switch is turned on. Stated illustratively, the winker switch is normally set to light a right parking lamp when a car is parked on the left side of a street or road and a winker switch is set to light a left lamp when a car is parked on the right side of a street. Accordingly, if one of the parking signal lamps is disconnected, both the lamps may fail to be lit, making prevention of accidents imperfect. Furthermore, it is necessary to provide an electric circuit specially for the purpose.
The present invention is made taking the abovementioned inconveniences into consideration and it is a primary object of this invention to provide an electric circuit for automatically lighting parking lamps of a car at dusk, in which, when it becomes dark, right and left parking lamps are independently lit in an automatic manner or both the lamps are simultaneously lit by preliminarily setting a knob.
Another object of the present invention is the provision of an extremely economical electric circuit for automatically lighting parking lamps of a car at dusk, which is equipped without changing operations of existing switches or circuits with which the vehicle is already equipped.
Another object of the present invention is the provision of an electric circuit for automatically igniting parking lamps of an automobile at dusk, in which the circuit is so adapted as to light a parking lamp on the side of the vehicle to which a switch is connected during parking, and when it becomes dark, and to make a third person know the parking-position of the car thus preventing accidents such as rear-end collisions.
Accordingly the present invention comprises an electric circuit for automatically igniting parking lamps at dusk which comprises a light detecting circuit composed of one or more photoconductive elements, and one or more relays connected to the photoconductive element and having a plurality of contacts connected to a belowmentioned parking lamp circuit; the parking lamp circuit adapted to be selectively operated through operation of the relay of said light detecting circuit thereby to ignite one or all of parking lamps; and a switching circuit composed of a relay connected between an ignition switch arranged for closing and opening a power source and the light detecting circuit and having a plurality of contacts breaking or completing a winker circuit and the light detecting circuit according to operation of said ignition switch.
A further subject of the invention lies in an electric circuit for automatically igniting parking lamps at dusk which comprises a switching circuit composed of an ignition switch for opening and closing a power source, and a relay connected to said ignition switch and operating a parking lamp circuit and a winker circuit according to the operation of said ignition switch; a light detecting circuit composed of a photoconductive element, a relay connected to said photoconductive element and operating through said photoconductive element when said ignition switch is opened, and transistors connected to said relay; and a parking lamp switch connected between the relay of said light detecting circuit and a lamp circuit, said parking lamp switch igniting one or all of parking lamps independently or under cooperation of said winker switch according to the operation of said relay of light detecting circuit.
The accompanying drawings show several embodiments of an electric circuit for automatically igniting parking lamps at dusk, wherein,
FIGS. 1 and 2 are connection diagrams of electric circuits in which a pair of relays are employed in a light detecting circuit section;
FIGS. 3 and 4 show connection diagrams of electric circuits in which a pair of relays and a transistor are employed in the light detecting circuit section;
FIG. 5 shows an electric circuit in which only a relay is connected to the light detecting circuit section and a parking lamp switch is connected to a parking lamp circuit.
Each example will be explained according to the accompanying drawings, wherein the same elements are represented by the same reference numerals. In FIGS. 1 to 4, the electric circuit for automatically igniting parking lamps at dusk is composed of three circuit sections, namely, a light detecting circuit section with a photoconductive element, a relay section which connects a power source to said light detecting section and has a switch to operate without troubles with existing parking and flasher circuits, and a lighting circuit for igniting any of parking lamps in response to the operation of said relay section. They will respectively be described in detail as follows.
A light detecting circuit section A (FIG. 1) comprises a photoconductive element P, for example, of cadmium sulphate (CdS), which converts a strength of light to a variation of electric current, affected by ambient light, a switch SW2, a left relay 2RL and a right relay 2RR connected respectively to a left fixed contact 2b and a right fixed contact 2c of said switch SW2. The movable contact 2a of said switch SW2 is normally kept in the neutral position. A protective resistor R1 is connected between a battery 5 and the photoconductive element P. When outer light reduces and the resistance of the photoconductive element P increases, the voltage at a connection point Q increases to impress current on the one of relays 2RR or 2RL to which the movable contact 2a is connected, thus operating an undermentioned parking lamp lighting circuit C. As mentioned later, a photoconductive element is preferred to be of little light resistance when a transistor Tr1 is not employed in the light detecting circuit section A.
The relay circuit section B includes an ignition switch SW1 connected between the battery 5 and a relay 1R and closed when an engine key is put in and turned as in the ordinary manner.
Accordingly the relay circuit section B operates depending upon whether a circuit is closed or opened between the terminals 1a and 1b of the ignition switch SW1 to make the electric circuit for automatically igniting parking lamps operate normally and set the circuits in use so as not to be influenced by this electric circuit. The above-mentioned relay 1R has three contacts a, b and c. The contact a controls connection of the power source 5 to the above-mentioned light detecting circuit section A and is normally opened when the power source is connected to the relay 1R of section B and contacts b and c coact to control energization or deenergization of coils 8a or 8b of a relay 8.
Ignition circuit section C is operated by the switch SW2 of the light detecting circuit section A to ignite right or left parking lamps including tail lamps.
Reference characters 9L and 9R indicate respectively a left and a right parking lamp section, the left parking lamp section 9L comprising a left parking lamp 10LL and a left tail lamp 11LL, and the right parking lamp section 9R including a right parking lamp 10LR and a right tail lamp 11LR. These lamps are connected to a group of contacts, d, e, f and g which are operated together according to energization or deenergization of the right and left relays 2RR and 2RL of said light detecting section. Of these contacts, movable contacts, d1, e1, f1, and g1 are normally retained in the positions shown in the drawings. The above description of FIG. 1 also applies to FIGS. 2-4.
A switch SW3 for parking and tail lamps is manually operable and has a fixed contact 3a connected to the terminal of the battery 5, a fixed contact 3b connected to parking lamps 10LR and 10LL, a fixed contact 3c connected to tail lamps 11LL and 11LR, and a movable contact 3d connected to a manually operable knob K. The operation of this switch SW3 is such that at the first downward motion of the knob K manually operated in the direction of arrow, the movable contact 3d is brought into contact with the fixed contact 3b connected to the parking lamps 10LL and 10LR, the fixed contact 3c connected to tail lamps 11LL, 11LR, and the fixed contact 3a connected to the power source 5, thereby simultaneously connecting these contacts. By another downward motion of the manually operated knob K in the arrow direction, the movable contact 3d is moved downwardly to detach from the fixed contact 3b, thereby connecting the fixed contact 3c with the fixed contact 3a connected to the power source to make a close circuit therebetween. Accordingly, if a driver manually operates the knob K downwardly, for example, at the first downwardly pulling operation of the knob by the driver, left and right parking lamps 10LL, 10LR and tail lamps 11LL, 11LR are simultaneously ignited, and at the subsequent pulling operation of the knob K in the direction of arrow by the driver, only the left and right tail lamps are turned on.
Though small differences due to the kind or the year of a car are seen in a flasher or a stop signal lamp circuit, they are included in the examples shown in FIGS. 1 to 4. In each drawing 13 indicates a flasher unit which is, in FIGS. 2 and 4, connected between the battery 5 and the terminal a2 and h2, respectively of the corresponding contact a which is actuated by the relay 1R. Flasher lamps 12LL and 12LR are connected to said flasher unit 13.
Furthermore, in FIGS. 3 and 4, the reference characters Tr1 indicates a transistor to the collector side of which the right and left relays 2RL and 2RR are connected and the prescribed photoconductive element P is connected between the emitter and the base of said transistor. In FIG. 2, 14 indicates a positive thermistor connected to protect the photoconductive element.
Said thermistor 14 is selected from those having such characteristics that its resistance at the normal temperature, 25° C, is equivalent to a light resistance of the photoconductive element P during day time and noticeably increases due to self-heating taking place when, in the day time, the resistance of said photoconductive element P is decreased to apply several volts of voltage to the thermister, thus serving to reduce the power consumption of the photoconductive element P, and that as it becomes dark, the resistance of said photoconductive element P increases to reduce the voltage to be impressed on this positive characteristic thermistor 14, so that the thermister 14, at this time, operates as a resistor having a value less than 100 Ω.
Referring to the above-mentioned circuits of FIGS. 1 - 4, the operations are explained as follows:
When the terminals 1a and 1b of the ignition switch SW1 are connected to each other by turning on the engine key in the usual manner, the relay 1R is operated to move respective contacts a, b and c to the positions as shown in the respective drawings.
In such a state, when the switch SW2 is operated to bring its movable contact 2a into contact with either the left fixed contact 2b or the right fixed contact 2c, the corresponding flasher lamp 12LL or 12LR flashes through the medium of the flasher unit 13.
Then, when a driver stops a car and takes off the engine key from the ignition switch SW1, the circuit is opened between the terminals 1a and 1b, and the selector relay 1R connected from said terminals is deenergized to move its contacts a, b and c to their other positions. Consequently, in FIGS. 1 and 3, the contact a is closed and the contacts b and c are opened, and in FIGS. 2 and 4, the movable contacts a1 and h1, respectively are switched to the terminals a3 and h3, respectively and the movable contacts b1 and c1 are switched to the terminals b3 and c3 from the terminals b2 and c2.
Then, as soon as the power source 5 is connected to the light detecting circuit section, power supply to the flasher circuit consisting of the flasher unit 13 and the flasher lamps 12LL and 12LR is stopped.
When it becomes dark and the resistance of the photoconductive element P increases, the voltage at the connection point Q increases to operate either the left relay 2RL or the right relay 2RR, to one of which the switch SW2 is preliminarily set. More particularly as to FIGS. 3 and 4, when it becomes dark and the resistance of the photoconductive element P increases, the bias voltage of the base of the transistor Tr1 increases in the forward direction and said transistor is turned on to operate the relay 2RL or 2RR to which the switch SW2 is turned.
Thus, when said relay 2RL or 2RR is operated, for example, when the right relay 2RR is operated, its movable contacts d1 and e1 are simultaneously turned to the fixed contacts d3 and e3 from the fixed contacts d2 and e2.
Accordingly the parking lamp 10LR and the tail lamp 11LR located on the right side lamp ignition circuit section 9R are lit by the power supplied from the battery 5 through the line L.
In such a case, the switch SW3 is manually operated to move its movable contact 3d into contact with the fixed contact 3b for the parking lamps or the fixed contact 3c for the tail lamps, the parking lamp 10LL or tail lamp 11LL of the left side ignition circuit section 9L is lit.
FIG. 5 shows a still further embodiment of the present invention, in which the light detecting circuit section includes only a relay and two transistors, said relay being actuated when one of said two transistors is rendered conductive, a switch for parking lamps is connected between said relay and the parking lamp circuit, said switch for parking lamps igniting any or all of parking lamps in cooperation with said relay and a winker switch.
Similarly to the above-described embodiments of FIGS. 1-4, the ignition switch SW1 of FIG. 5 has one terminal connected to the anode of the power source 5 and other terminal connected to a resistor R2, to a relay 3RL and to the flasher unit 13 for winkers through the fuse F1. Said ignition switch SW1, like the usual ignition switch, is opened or closed according to the withdrawal or insertion of a key. The relay 3RL and the flasher unit 13 are grounded. An output terminal of the flasher unit is connected to a fixed contact m3 of a relay 4RL connected to the light detecting circuit. A fixed contact m4 of the relay 4RL is connected to the power source 5 through the fuse F2. One terminal of resistor R2 is connected to the photoconductive element P of CdS and a base of an NPN transistor Tr2. Other terminal of said photoconductive element P is connected to the anode of power source 5. The collector of transistor Tr2 is connected to the anode of power source 5 through a resistor R3 and to a base of another NPN transistor Tr3. The collector of said transistor Tr3 is connected to the anode of power source 5 through the relay 4RL. Emitters of transistors Tr2 and Tr3 are grounded. The resistor R4 is connected between the base of transistor Tr3 and ground, for the purpose of biasing the transistor.
The relay 4RL has a plurality of fixed contacts and movable contacts, in which the fixed contact m2 is connected to fixed contacts 4b, 4e of a switch SW4 for parking lamps; the fixed contact m4 is connected to fixed contacts 4c, 4f of the switch SW4, and the fixed contact m1 remains opened. The movable contacts m5 and m6 of said relay 4RL are connected to a movable contact 5a of a winker switch SW5. Fixed contacts 5b and 5c of said winker switch SW5 are connected to movable contacts k3 and k6 of relay 3RL, respectively. Fixed contacts k1 and k4 of said relay 3RL are connected to left and right winker lamps 14LL and 14LR through respective diodes D for preventing the feedback of current, respectively. Fixed contacts k2 and k5 are directly connected to the left and right winker lamps 14LL and 14LR, respectively. The winkers and parking lamps are respectively grounded at one terminal.
Movable contacts 4h, 4g of said switch SW4 for parking lamps are connected to the left-side and right-side parking lamps 15LL and 15LR, respectively, while fixed contacts 4a and 4d remain opened.
Operation of the thus connected electric circuit will be described.
The drawing shows that the ignition switch SW1 is now kept in the closed position, and current flows to coils of relay 3RL from the power source 5, so that the movable contacts k3 and k6 of relay 3RL are retained in contact with the fixed contacts k2 and k5, respectively. If the winker switch SW5 is operated to turn its movable contact 5a to one of fixed contacts 5b and 5c, either winker lamp 14LR or 14LL is ignited through the flasher unit 13, thereby flashing one of winker lamps 14LR and 14LL.
If the key is withdrawn from the ignition switch SW1 at the time of parking and resultantly the ignition switch is turned open, current flows to the coil of relay 3RL through the CdS photoconductive element P and the resistor R2, so that the movable contacts k3 and K6 of relay 3RL are turned into contact with the fixed contacts k1 and k4, respectively. If the switch for parking lamps SW4 is operated to move the movable contacts 4h and 4g into contact with the fixed contacts 4f and 4c respectively, the parking lamps 15LL and 15LR are ignited through the fixed contact m4 of relay 4RL. In this case, the parking lamps can be ignited if the ignition switch SW1 remains closed. None of the parking lamps can be ignited if the movable contacts 4h, 4g are connected to fixed contacts other than the fixed contacts 4c and 4f.
As it becomes dark and the ambient light gradually decreases, the resistance of the CdS photoconductive element P increases and current flowing to the base of transistor Tr2 becomes reduced. Consequently, said transistor Tr2 is rendered nonconductive, while current flows to the transistor Tr3 through the resistor R3, so that said transistor Tr3 becomes conductive. When said transistor Tr3 becomes conductive, current flows to the relay 4RL, and its movable contacts m5 and m6 are brought into contact with the fixed contacts m2 and m4, respectively. In this connection, if the switch for parking lamps SW4 is turned to make the movable contacts 4g and 4h contact with the fixed contacts 4b and 4e, respectively, current from the power source 5 flows to the parking lamps 15LL and 15LR through the fixed contact m4, the movable contacts m6 and m5 and the fixed contact m2 of relay 4RL, thereby igniting the parking lamps 15LL and 15LR.
If the switch SW4 for parking lamps is turned to move its movable contacts 4g and 4h into contact with the fixed contacts 4a and 4d and the winker switch SW5 is operated to make its movable contact 5a contact with either of fixed contacts 5b or 5c, current flows to one of left and right parking lamps 15LL and 15LR through the fixed contact m4 and the movable contact m6 of the relay 4RL, thereby igniting one of parking lamps 15LL or 15LR. Where ignition of parking lamps is not required, for example, when an automobile is put in the garage or the parking place, the winker switch SW5 is set to maintain its movable contact 5a in the neutral position, so that none of parking lamps 15LL, 15LR are ignited.
In the light detecting circuit A including the photoconductive element P and transistors Tr2 and Tr3, the potential at the junction point between said photoconductive element P and the resistor R2 becomes equal to that of the power source while the ignition switch SW1 is maintained in the closed position, hence the relay 4RL is kept inoperative. Therefore, the switching or relay circuit section B is brought into the normal operation.
The transistors connected to the light detecting circuit A are here shown as of the NPN type, but it is fully contemplated that PNP transistors are employable in place of the NPN transistors.
A plurality of photoconductive elements P may be employed if a plurality of AND circuits including diodes are additionally connected to the light detecting circuit. In this case, the plurality of photoconductive elements P may be arranged in desired places on the car body, so that if the light of head lamps of a following or coming car influences upon any of photoconductive elements to render it inoperative, the other photoconductive elements will perform a normal operation.
Thus, the plurality of photoconductive elements will more effectively contribute to prevention of a traffic accident than a single photoconductive cell will. In other words, any of plurality of AND circuits will surely operate to ignite all or desired parking lamps, as far as one of plurality photoconductive elements is in operation.
In embodiment of FIG. 5, a single relay 4R1 is employed in the light detecting circuit, said relay being connected to a plurality of transistors. The resistance of photoconductive element P increases as the ambient light decreases at dusk, and thereby one of transistors becomes nonconductive while the other transistor is turned conductive, thereby operating the relay to turn its movable contacts from one position to the other. The parking lamp circuit in this embodiment includes the winker switch SW5 and the switch for parking lamps SW4 connected to a group of contacts of relay 4RL, in which the switch for parking lamps SW4 conducts independently or under cooperation of the winker switch SW5 the ignition of all or any of parking lamps. In such circuit construction, if the winker switch and the switch for parking lamps are set to a position for igniting the parking lamps when a driver leaves the car, any of left and right parking lamps will be automatically ignited in the twilight hours, so that parking of the automobile is perceived by other cars.
The electric circuit for automatically igniting parking lamps at dusk of the present invention has many advantages that the circuit is simple in its construction and operates with reliability, which will be of great help to prevent a car from accidents such as a rear-end collision, and that the circuit of the present invention can be also easily incorporated into any existing circuits of any kinds of automobiles, without replacing their winker circuits or switch means and without changing their operation, which will attribute to economy and usability.