Electricity: motive power systems – Periodic – repetitious or successive operations control of... – Variable periods or intervals between controlling operations
Reexamination Certificate
2000-07-13
2002-01-01
Fletcher, Marlon T. (Department: 2837)
Electricity: motive power systems
Periodic, repetitious or successive operations control of...
Variable periods or intervals between controlling operations
C318S065000, C318S256000, C318S280000, C318S282000, C318S443000
Reexamination Certificate
active
06335601
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a wiper control device for actuating a wiper device mounted, for example on a motor vehicle and especially to a device for controlling the wiper device which is so designed as to change the rotational direction of the wiper motor between cases of high-speed operation and low-speed operation of the motor and decrease substantial length of a motor arm of the wiper linkage at the time of the high speed operation as compared with that of the motor arm at the time of the low speed operation through an arm-length adjusting device including an eccentric mechanism attached on the motor arm of the linkage in order to solve a difference in the wiping ranges at the time of high speed operation and low speed operation caused by a difference of inertial force of the wiper blade.
2. Description of the Prior Art
As an apparatus for wiping rain drops adhering to the windshield of the motor vehicle and ensuring the wide visual range of a driver, wiper apparatuses having various structure and function have been used. Recently, a wiper apparatus which is designed so as to be possible to select working speed of the wiper blade between continuous operation of two-level at high and low speeds and intermittent operation at a low speed according to the amount of rain-fall is used generally.
In the wiper apparatus of this kind, kinetic energy of the wiper blade at he time of high speed operation (high-speed mode) becomes larger than that of the wiper blade at the time of low speed operation (low-speed mode), therefore a phenomenon is observed in that the wiping range of the wiper blade at the time of high-speed operation becomes wider as compared with the wiping range at the time of low-speed operation of the wiper blade according to the difference in the inertial force of the wiper blade. Accordingly, there is defectiveness in that the windshield partially remains unwiped and the visual field becomes narrow at the time of low speed operation in a case where the wiping range of the windshield is set on basis of the oscillation range of the wiper blade at the time of high speed operation and the wiper blade runs out of the windshield glass at the time of high speed operation in a case where the wiping range of the windshield is set on basis of the oscillation range of the wiper blade at the time of high speed operation.
Applicant proposed previously a wiper linkage which was so designed as to solve the difference in the actual wiping range enlarged owing to addition of the inertial force of the wiper blade by setting the rotational direction of the wiper motor at the time of high speed operation conversely against that of the wiper motor at the time of low speed operation, making the substantial length of the motor arm of the wiper linkage at the time of high speed operation shorter than that of the motor arm at the time of low speed operation through an arm length adjusting mechanism attached to the motor arm and used with an eccentric bush to be turned as much as 180° at the time of switching over the rotational direction of the motor arm and reducing the structural wiping range of the wiper blade at the time of high speed operation as compared with that of the wiper blade at the time of low speed operation in Japanese Patent Application No.10-158026/98 in order to remove the difference in the wiping range caused by the difference in the operation speed of the wiper blade in the conventional wiper apparatus of the two-speed type.
In the newly proposed wiper linkage as mentioned above, however, it is different foundamentally from the conventional wiper linkage in the point that the rotational directions of the wiper motor at the high speed operation and the low speed operation are different from each other, so that there are various problems differing from the conventional linkage in switching control of the wiper mode (high-speed mode and low-speed mode), auto-stop control at the time of stopping the wiper apparatus and so on. For example, it becomes necessary to supply an electric current by changing the brush terminals of the wiper motor at the same time of changing the direction of the electric current in a case the wiper mode is changed over from the low-speed mode into the high-speed mode or from the high-speed mode into the low-speed mode, and the wiper blade goes back at the middle of the wiping range on the windshield glass, whereby not only a strange impression is given to the passengers, but also an unwiped area remains on the windshield glass until the wiper blade comes back from the turning position in a case where the rotational direction of the wiper motor is changed regardless of the position of the wiper blade. So that there is a problem in that it is necessary to perform special control differing from the conventional wiper linkage, and development of the wiper control device has become on subject, which is suitable for the wiper linkage so designed as to remove the difference in the wiping range caused by the difference in the operation speed of the wiper blade by changing the rotational direction of the wiper motor between the low speed operation and the high speed operation.
SUMMARY OF THE INVENTION
This invention is made in view of the aforementioned problem in the control of the wiper linkage of which wiper motor is different in the rotational direction between low speed operation and high speed operation, and it is an object to provide a wiper control device which is possible to smoothly switch over the rotational direction of the wiper motor together with the rotational speed and execute the control without causing the strange impression and the unwiped area at the time of changing the operation speed and stopping the wiper blade.
In order to accomplish to the aforementioned object, the wiper control device according to this invention is provided with a wiper switch, a wiper motor, a position switch, a controller and a motor driving circuit, and the controller is so designed as to change the rotational direction of the wiper motor at the time when the wiper blade arrives in the lower turning position or the upper turning position after the low-speed command signal or the high-speed command signal generated from the wiper switch is switched over into the high-speed command signal or the low-speed command signal, respectively. Namely, in the case where the wiper switch is switched over from the low-speed mode to the high-speed mode, or from the high-speed mode to the low speed mode, the rotation of the wiper motor is switched over from the low-speed forward rotation to the high-speed reverse rotation, or from the high-speed reverse rotation to the low-speed forward direction when the wiper blade arrives at either the lower turning position or the upper turning position, that is when the wiper linkage is in the dead point, therefore the unnatural phenomenon is solved in that the wiper blade goes back at the middle of the windshield glass according as the rotational direction of the wiper motor is changed.
In the wiper control device according to a preferred embodiment of this invention, the position switch is provided with a high-potential plate connected with the power source, a low-potential plate grounded, a clutch member rotatable by being pushed against a push member rotating together with the output shaft of the wiper motor only in a direction energized by the push member, and a movable contact attached to the clutch member so as to slidingly come in contact with the high and low-potential plates. Namely, the movable contact is not secured to the output shaft of the wiper motor and the wiper blade and so structured as to stay in the present position while the output shaft of the wiper motor makes nearly one revolution in a case where the wiper blade moves backward, or the rotational direction of the wiper motor is changed. Accordingly, the chattering of the wiper blade caused by obstacles such snows, and the signal change is obtained suitably for reversing control of the wiper motor from the mo
Kato Masaru
Matsumoto Yasuki
Yamazaki Haruo
Fletcher Marlon T.
Jidosha Denki Kogyo Kabushiki Kaisha
Sughrue & Mion, PLLC
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