Electric Automatic Door Locking System

Abstract

An electric automatic door locking system that is responsive to a plurality of conditions for electrically locking all the doors of a vehicle. In order for the doors to be locked, a driver must be seated in the vehicle, the vehicle engine running, the transmission engaged and the doors closed. When all of these conditions are satisfied, the doors will be automatically locked regardless of vehicle speed. Circuitry is provided to prevent overheating of the door locking solenoids once the doors are locked and remain closed.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to a door locking system for a motor vehicle and, in particular, to an electric door locking system responsive to various conditions of the vehicle regardless of vehicle speed.

2. Prior Art

Conventional door locking systems are mostly manual with or without power assist. Several systems are actuated by switches at either front door of the vehicle energizing the solenoid locking mechanisms at all the doors. These systems are not responsive to any condition except that of the occupant wanting the doors locked. Additional door locking systems are sub-systems of larger vehicle systems such as security systems wherein the doors are locked in response to a manual operation of actuating a switch. Still, another systems are fluid in character either hydraulic or vacuum and are responsive to but one or two conditions having to do with vehicle motion.

SUMMARY OF INVENTION

It is an object of the invention to automatically lock all doors of a vehicle before the vehicle is moved under its own power.

It is another object of the invention to allow the operator override of the automatic sytem at his discretion.

It is yet another object of the invention to require the presence of a driver in the vehicle before all doors are automatically locked.

These and other objects of the invention will become apparent from the following detailed description of an automatic electric door locking system for a motor vehicle. The system is actuated upon the occurrence of several operating conditions, namely, the presence of a driver, the ignition on, the engine running, the doors closed and the transmission engaged in a moving position. Once all of these conditions are satisfied, the doors are automatically locked through the operation of a solenoid operating at each door lock location. The solenoid is energized by an electric pulse of a predetermined length so as to preclude a constant power drain on the vehicle battery. Once the doors are locked and remain closed, any change of the aforementioned conditions will not affect the control circuitry or the solenoid operation. An additional feature includes a controller that is independent of any other door locking system such as security systems.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a block diagram of the automatic door locking system of the present invention;

FIG. 2 is a schematic of the control unit of FIG. 1;

FIG. 3 is a plurality of timing diagrams representing the operation of several of the components illustrated in FIG. 2;

FIG. 4 is a schematic of an alternative embodiment of the control unit of FIG. 1;

DETAILED DESCRIPTION

Referring to the figures by the characters of reference, there is illustrated in FIG. 1 a block diagrammatic schematic of an electric automatic door locking system as may be found in a motor vehicle. The control unit 10 of FIG. 1 is responsive to a plurality of system requirements or conditions found within the vehicle and in response to these conditions, the control unit 10 initiates the operation of solenoids in each door of the vehicle for activating the locking mechanism. For the purposes of this description, trunk lids and engine compartment hoods are considered as being doors inasmuch as their locking mechanisms may be solenoid actuated.

The first requirement is an indication of the presence of a driver 12 for operating the vehicle. A second requirement is an indication of the engagement of the transmission 14 into a driving connection. The third requirement is an indication that the engine 16 of the vehicle is in a running or "on" condition so that the vehicle may be moved. A fourth requirement is an indication that all the doors 18 are closed. The control unit in response to electrical signals from the means representing these requirements will generate an electrical signal to each of the solenoid control units 20 for actuating the door locking mechanism at each door.

As illustrated in FIG. 1, a requirement for a signal indicating that the ignition 22 is turned on is also applied to the control unit 10. Typically, this signal is from the ignition switch and it serves to connect a source of power such as the vehicle battery to the control unit 10. In this manner, power is applied to the system just prior to its activation.

In an automatic door locking system there is an additional requirement for a manual override control 24 so that a vehicle operator may, in his discretion, lock the several doors of the vehicle simultaneously. In most motor vehicles, the manual override control 24 is generally a momentary contact switch 26 typically associated with the door locking pushbuttons on some or all of the doors of the vehicles. This manual control 24 operates the control unit 10 regardless of the state of the other condition indicating means.

Referring to FIG. 2 which is a schematic incorporating the condition indicating means of FIG. 1 with the control unit 10 wherein each of the condition indicating means is represented by switches SW1-SW5. In this preferred embodiment, the driver present indicating means 12 or first means is typically a normally open switch SW1 positioned within the seat of the vehicle and responsive to the presence of the driver sitting thereon. Such a switch SW1 may be a normally open mechanical switch or an electronic switch wherein in its output stage is an electronic switch such as a switching transistor. In FIG. 2 this first means is indicated as a normally open switch SW1. The means 14 for indicating the engagement of the transmission or the second means is indicated as a normally closed switch SW2 in FIG. 2. In a similar manner the engine operating condition means 16 or third means and the door closed condition indicate means 18 or fourth means are also represented as normally closed switches SW3 and SW4 respectively. The ignition indicate means 22 is represented as a normally open switch SW5 in FIG. 2.

The control unit 10 of FIG. 1 as schematically illustrated in FIG. 2 comprises a first NPN transistor 28 which is electrically connected in circuit between the ignition switch SW5 and ground. Electrically connected between the ignition switch SW5 and the collector of the transistor 28 is a load resistor 29 for controlling the amount of current in the circuit. A second resistor 33 is electrically connected to the ignition switch SW5 and through a biasing diode 35 to the base of the first transistor 28. Whenever the ignition switch is on, this circuit biases the first transistor into conduction. Electrically connected between the junction of the second resistor 33 and the biasing diode 35 is the driver present switch SW1 which when operated supplies a ground potential to the anode of biasing diode 35. The voltage drop across the biasing diode 35 when the switch is operated is sufficient to drive the first transistor 28 out of conduction.

Electrically connected to the collector of the first transistor 28 and substantially in parallel with each other are the anode connections of a plurality of diodes 30-32. The output or cathode of each diode 30-32 is connected through switches SW2, SW3 and SW4 respectively to ground. As will hereinafter be shown each of these diodes 30-32 function as a gating diode and together form a logical AND circuit. Referring to FIG. 2 when the first transistor 28 is driven out of conduction its collector will remain at ground potential if any one of the three switches SW2, SW3 and SW4 are closed.

The output stage of the control unit 10 is a second NPN transistor 34 having its collector-emitter circuit electrically connected across the source of power 36. The base of the second transistor 34 is electrically connected through a capacitor 38 and a blocking diode 40 to the collector of the first transistor 28. The capacitor 38 couples the voltage level change at the collector of the first transistor 28 to the second transistor 34 or driving the second transistor into conduction when the voltage change is in a positive direction. Electrically connected between the base of the second transistor 34 and ground is a diode 42 poled in such a direction as to bypass to ground any negative voltage signals appearing on the base lead. In the preferred embodiment, a relay 44 is electrically connected in the collector circuit of the second transistor 34 whereby the normally open contacts 46 of the relay connect the source of power 36 to each of the solenoid operated door locks 20 whenever the second transistor 34 is driven into conduction.

The manual override control switch 24 illustrated as a momentary contact switch 26 is electrically connected through a resistor 48 from the source of power 36 to the base of the second transistor 34. Thus, whenever the switch 26 is actuated, the second transistor 34 is driven into conduction. For the purposes of voltage transient protection zener diodes 50 and 52 are electrically connected across the emitter-collector of each of said first and second transistors 28 and 34. In addition, the zener diode 50 functions to maintain the voltage level at the collector of the first transistor 28 at a level no greater than the value of the zener.

As illustrated in FIG. 2, electrically connected in series with the capacitor 38 and between the anodes of the two gating diodes 30 and 31 in series with switches SW3 and SW4 respectively is the blocking diode 40. This diode 40 functions to control the discharge of the capacitor 38 through the gating diode 32 and switch SW4. Once the doors 18 are locked as a result of the proper operation of switches SW1-SW5 inclusive, any actuation of switches SW1, SW2 or SW3 will not cause the second transistor 34 to be driven into conduction. Therefore, any physical movement of the driver in his seat or the shifting of the transmission in and out of gear or a stalling of the vehicle will not cause the door lock solenoids 20 to be re-energized once the doors are initially locked and have not been opened.

The operation of the system of FIG. 2 is illustrated by the timing diagram of FIG. 3 which diagrammatically shows the operation of the five switches SW1-SW5 and the resultant voltage or current signals at points A, B, C and D in FIG. 2. As illustrated by the voltage waveform at point B once the capacitor 38 is charged, it's not discharged until switch SW4 is closed. The charging time constant generated by the capacitor 38 and the resistance 29 operates to control the pulse length duration applied to the relay coil 44 in the collector circuit of the transistor 34. Therefore, once the solenoids 20 have actuated the door lock mechanisms, the power is automatically removed from the soldenoid coils 20 when the second transistor 34 is driven out of conduction.

Referring to FIG. 4, there is illustrated a circuit modification of the control unit 10 of FIG. 1. The circuit location and operation of the manual switch 26 in this modification is such as to have its operation not influenced due to any circuit component failure. Other changes to the control unit 10 will hereinafter be described. In this modification, the switches SW1-SW5 retain the same character designation as in FIG. 2.

The seat switch SW1 is electrically connected in the base circuit of a first PNP transistor 54. The emitter of the first transistor 54 is electrically connected through the ignition switch SW5 to a source of power. The collector of the first transistor 54 is electrically connected through a first and second resistor 56 and 58 to a logical junction of the anodes of three gating diodes 60, 62 and 64. A fourth diode 66 is electrically connected to the cathode of one of the diodes 64 and each of four diodes 60, 62, 64 and 66 perform the same function as diodes 30, 31, 40 and 32 respectively. Electrically connected between the first and second resistors 56 and 58 is a zener diode 68 to maintain the voltage to the logical junction at a level no greater than value of the zener. In this embodiment the zener value is 8.2 volts. The anode of the diode 66 and the cathode of diode 64 are electrically connected to one side of capacitor 70. The door switch SW4 is connected between ground and the cathode of diode 66 and the oil pressure switch SW2 and the transmission switch SW3 are electrically connected respectively between the cathodes of the diodes 60 and 62 and ground. As in FIG. 2, the logic junction is an AND circuit for the five conditions as represented by the switches SW1-SW5.

The other side of the capacitor 70 is electrically connected to the base of a NPN transistor 72 and also through a discharging resistor 74 to ground. The emitter of the NPN transistor 72 is electrically connected to ground through a diode 75 to ground. The diode provides reverse voltage protection to the transistor when the cathode of the diode 64 is driven to ground. The collector of the NPN transistor 72 is electrically connected through a resistor 76 to the base of a second PNP transistor 78. The emitter of the second PNP transistor 78 is electrically connected to the emitter of the first PNP transistor 54. In the collector circuit there is electrically connected to ground, a parallel circuit having a relay coil 80 and a suppression diode 82. Additionally, the manual control switch 26 is electrically connected between the collector of the second PNP transistor 78 and the source of power. If any of the transistors should fail, the manual switch 26 will still operate the relay 80 and thereby operate the door locks. A normally open contact of the relay 80 similar to the normally open contact 46 in FIG. 2 connects the source of power to the door locking solenoids.

In both modifications, the manual switch 26 may represent any one or all of several different circuits which all perform the function of causing the doors to be locked. One example of such a circuit is the automatic locking of the doors of a vehicle in a vehicle security alarm system. Such a system may be that described and claimed in the copending application to J. J. Kopera, Jr. entitled "Motor Vehicle Electronic Security Alarm System Using Sequence Control Arming" filed on Sept. 8, 1972, having Ser. No. 287,401.

Assuming a normal sequence of operation, the circuit of FIG. 4 operates as follows. The circuit illustrates the normal condition of all the switches. All of the transistors 54, 72 and 78 are in an electrically off condition.

The driver occupies his seat closing SW1. Next, the doors are closed which are represented by the opening of the door switch SW4. The ignition key is inserted in the ignition lock and turned causing the switch SW5 to close, supplying power to the emitters of the first and second PNP trnsistors 54 and 78. The first transistor 54 is driven into conduction causing the zener diode to conduct to hold the voltage between the first and second resistors 56 and 58 at the zener voltage level. The one side of the capacitor 70 is at ground level due to SW2 and SW3. When the engine is started, the oil pressure switch SW2 is opened and when the transmission is engaged, the transmission switch SW3 is opened driving the one side of the capacitor 70 to the zener voltage level. This voltage swing is reflected across the capacitor 70 to the base of the NPN transistor 72 driving it into conduction thereby drawing base current from the second PNP transistor 78 driving it into conduction thereby energizing the relay 80.

After a period of time as determined by the charge time constant of the capacitor 70 and the charging resistors 56 and 58, the NPN transistor 72 is driven out of conduction. As in FIG. 2, any subsequent operation of SW1-SW3 and SW5 will not discharge the capacitor 70 and reset the circuit; only by the opening of a door which is indicated by the closing of the door switch SW4 will the capacitor 70 be discharged.

There has thus been shown and described an automatic door locking system for use in a motor vehicle such as an automobile. The system is responsive to several operating requirements or conditions of the vehicle, namely, the presence of a driver 12 with the ignition on 22, the motor running 16, and the transmission engaged 14 for automatically locking the doors 18. The system is not responsive to any predetermined speed of the vehicle and as such will lock the doors immediately prior to the vehicle moving.

Claims

What is claimed is:

1. In a motor vehicle having a plurality of doors with each door being provided with door latching and locking mechanism, an electric automotive door locking system comprising:

a source of power;

a solenoid control unit operatively connected to the door locking mechanism at each door of the vehicle, said solenoid control unit being responsive to an electrical signal for actuating the door locking mechanism;

an AND circuit formed by a first switch responsive to weight on a vehicle seat corresponding to the driver's position, a second switch responsive to engagement of the vehicle transmission into a drive position, a third switch responsive to running of the vehicle engine and a fourth switch responsive to closing of the vehicle doors, each of said first, second, third and fourth switches being operative to supply a ground voltage signal;

a logical control unit electrically responsive to said AND circuit for generating said electrical signal applied to each of said solenoid control units; and

an override control for electrically actuating the door lock mechanism regardless of the state of said AND circuit;

said logical control unit comprising:

a first transistor having its emitter-collector circuit electrically connected with said AND circuit so as to be capable of coupling said AND circuit with said source of power;

a second transistor electrically connected with said solenoid control unit so as to be capable of connecting said source of power to said solenoid control unit; and

a capacitor having one side thereof connected with said first transistor and its other side connected with said second transistor, said capacitor being responsive to a voltage level change from ground for causing said second transistor to energize said solenoid control unit.

2. In an electric automatic door locking system according to claim 1 additionally including a diode in said AND circuit to control the discharge of said capacitor only upon opening of a vehicle door.

3. In an electric automatic door locking system according to claim 1 wherein said first and second transistors are of like conductivity.

4. In an electric automatic door locking system according to claim 1 additionally including a third transistor interposed in series circuit between the other side of said capacitor and the base of said second transistor, the base of said third transistor electrically connected to said other side of said capacitor and the emitter-collector circuit of said third transistor electrically connected to the base of said second transistor controlling the conduction thereof.

5. In an electric automatic door locking system according to claim 4 wherein said override control is electrically connected in parallel circuit with said second transistor and in series circuit with said solenoid control unit for energizing said solenoid control unit independently of said second transistor.