Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
1996-05-31
2001-01-30
Horabik, Michael (Department: 2735)
Communications: electrical
Continuously variable indicating
With meter reading
C340S870030, C455S092000, C307S010100
Reexamination Certificate
active
06181254
ABSTRACT:
THE FIELD OF THE INVENTION
The present invention relates to the art of remote keyless vehicle entry systems and, more particularly, to such a system wherein a portable remote transmitter has a normal mode of operation for transmitting a vehicle function request signal in response to actuation of a vehicle function request switch and a passive mode of operation during which the transmitter automatically and repeatedly transmits the vehicle function request signal.
DESCRIPTION OF THE PRIOR ART
Remote keyless entry (RKE) systems are known in the art for controlling the locking and unlocking functions of a motor vehicle door lock. Such systems include a receiver mounted in a motor vehicle and a portable hand held transmitter located remote from the receiver. The receiver has a memory that stores one or more security codes, each of which identifies a transmitter that is authorized entry into the vehicle. Each transmitter is provided with a plurality of manually actuatable switches, each representative of a vehicle control function to be performed, such as the unlocking or locking of the vehicle door or the unlocking of the vehicle trunk lid. The transmitter includes circuitry that responds to the actuation of one of the switches to transmit a digital signal that includes a security code that uniquely distinguishes the transmitter from a plurality of similar transmitters and a function code representative of the control function to be performed, such as the unlocking of a door. When the receiver receives such a digital signal, it compares the received security code with each stored security code to determine whether the security code was transmitted by an authorized transmitter. If a match takes place, the receiver responds to the function code by causing performance of the control function requested, as by unlocking a vehicle door. A system described above is disclosed in the U.S. Patent to Lambropoulos, et al. U.S. Pat. No. 4,881,148, the disclosure which is herein incorporated by reference.
A passive RKE system is one in which the operator need not push a switch button on the remote transmitter in order to transmit a coded signal to a vehicle receiver and thereby unlock a vehicle door or the like. Instead, such a system employs a transmitter that periodically transmits a coded signal which is received by the vehicle receiver to cause a performance of a vehicle function, such as opening a vehicle door. The function takes place once the transmitter is within the operating range of the vehicle receiver. Also, in such a passive system, the vehicle doors may be automatically locked as the operator leaves the operating range of the vehicle receiver. Such a passive RKE system may be of great convenience to an operator such as when the operator is unable to operate the transmitter switch button when carrying a load of groceries. Such a passive RKE system does require that the transmitter periodically transmit a vehicle function request signal so that the vehicle receiver knows when the transmitter has approached to within the operating range of the vehicle receiver. The transmissions consume power leading to rapid discharge of batteries contained in the transmitter housing. To reduce power consumption, the transmitter includes a motion detector and provides the periodic transmissions only when the transmitter is being jostled about. Such a system is disclosed in the U.S. Patent to Waraksa, et al. U.S. Pat. No. 4,942,393.
The U.S. Patent to Fujii, et al. U.S. Pat. No. 5,379,033 discloses a RKE system wherein the transmitter carries two buttons A and B each for causing transmission of a request signal for the same vehicle function, i.e., such as UNLOCK DOORS. If the operator depresses switch button A, the vehicle function request signal is transmitted periodically over a certain period of time. When switch button B is depressed, the vehicle function request signal is transmitted only once. Unfortunately, switch button B takes up valuable space on the transmitter housing, reducing the amount of space available for buttons for other functions and increasing the complexity of the transmitter switch array.
SUMMARY OF THE INVENTION
In accordance with the present invention, a portable transmitter is provided for use in a remote keyless entry system having a vehicle receiver responsive to a vehicle function request signal transmitted by the transmitter for controlling performance of a vehicle function. The transmitter includes a vehicle function request switch and a controller having a normal mode of operation during which it is responsive to closure of the switch for operating the transmitter for transmitting the vehicle function request signal. The controller has a passive mode of operation in response to closure of the same switch for more than a given period of time and during which passive mode the controller operates the transmitter to automatically and repeatedly transmit the vehicle function request signal.
REFERENCES:
patent: 4385204 (1983-05-01), Wine
patent: 4663626 (1987-05-01), Smith
patent: 4881148 (1989-11-01), Lambropoulos et al.
patent: 4942393 (1990-07-01), Waraksa et al.
patent: 5379033 (1995-01-01), Fujii et al.
patent: 5412377 (1995-05-01), Evans et al.
patent: 5517187 (1996-05-01), Bruwer et al.
patent: 5942985 (1999-08-01), Chin
Asongwed Anthony A.
Horabik Michael
Tarolli, Sundheim, Covell Tummino & Szabo L.L.P.
TRW Inc.
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