Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Reexamination Certificate
1998-07-28
2001-02-20
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
C701S001000, C701S050000, C701S036000, C187S222000, C414S266000, C414S275000, C414S347000
Reexamination Certificate
active
06192301
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a self-diagnostic method for a forklift truck, and more particularly to a method for diagnosing or testing condition of various components for a forklift truck selectively, identifying the resultant test codes collectively on a display after completing the test, and initiating a quick test mode by simply manipulating an accelerator pedal and a direction lever of the forklift truck during a run mode.
BACKGROUND OF THE INVENTION
Forklift trucks have been used either to lift goods of relatively heavy weight up to an elevated location or to lower the goods on the ground. The forklift trucks also can be used to move the goods from one place to another within a limited working area. Depending on the power sources employed, the forklift trucks are classified into an engine-driven forklift truck which may usually operate in an outdoor area and an electromotive forklift truck which are suitable for indoor operation, thanks to its reduced or little emission of exhaust gas and noise.
It is well known in the art that the electromotive forklift truck includes an electric travel motor whose speed and direction is controlled by a controller in response to external command signals. In addition to the electric travel motor, the electromotive forklift truck is provided with a variety of electric components that have the possibility of failure during their use. Since the failure of the electric components will make the forklift truck inoperable, it would be desirable to provide means for diagnosing and displaying the condition of the electric components in an efficient fashion so that the operator or repairman can take appropriate measure.
Background concerning a conventional method for diagnosing the forklift truck can be found in U.S. Pat. No. 4,521,885 by Melocik et al. The Melocik et al patent teaches a method for diagnosing the forklift truck in sequential order when the mode selector is in a diagnostic position. The diagnosing steps are predetermined by a software program.
However, the conventional diagnostic method has a disadvantage that it takes too long time to carry out the diagnosis, since the diagnosing procedure is automatically executed up to a final check point according to a programed schedule in sequential order even though the operator wants to give up halfway the diagnosis.
Additionally, the conventional diagnostic method poses a problem that the operator should repeatedly ascertain the resultant test code on the display during the period of test as the test code is temporarily displayed on the display each time a single sort of test is completed. Another problem of the conventional diagnostic method is that the operator can not initiate the test mode quickly during the run mode, since test switches need to be actuated in order to perform the in-service test.
SUMMARY OF THE INVENTION
The present invention is directed to overcoming one or more of the problems as set forth above.
It is an object of the invention to provide a self-diagnostic method that enables the operator to selectively check and diagnose condition of electric components for a forklift truck within a shortened period of test time.
It is another object of the invention to provide a self-diagnostic method that enables the operator to verify, at one time, all of the result ant test codes displayed on the display after finishing the test.
A further object of the invention is to provide a self-diagnostic method that enables the operator to initiate the test mode quickly during a run mode by simply manipulating an accelerator pedal and a direction lever.
In order to accomplish the above objects, the present invention provides a self-diagnostic method for a forklift truck, comprising the steps of: providing a mode selector with a diagnostic mode and a run mode, a fuse, a key switch, an accelerator, a direction switch having forward and reverse positions, a tilt switch, contactor coils, and a controller; initiating a main routine by the controller; reading a signal from the mode selector to decide which mode is selected from that the diagnostic mode and the run mode; identifying that the fuse is removed and the key switch is turned on when the diagnostic mode is selected; checking condition of the switches and the accelerator selectively according to an inputted diagnostic command in the order of priority to produce error codes in case of failure detection; saving the error codes occurred; and displaying the error codes when the tilt switch is turned on.
In accordance with the present invention, it is preferred that the self-diagnostic method for a forklift truck further comprises the steps of: reading a signal from the mode selector to verify whether the mode is changed; checking condition of the contactor coils according to an inputted diagnostic command in a sequential order to produce error codes in case of failure detection; and displaying the error codes occurred.
In accordance with the present invention, it is preferred that the self-diagnostic method for a forklift truck still further comprises the steps of: identifying that the key switch is turned on when the run mode is selected; checking condition of the switches and the accelerator selectively according to an inputted diagnostic command in the order of priority to produce error codes, in case of failure detection; and displaying the error codes occurred.
In accordance with the present invention, it is preferred that the self-diagnostic method for a forklift truck even further comprises the steps of: identifying that the accelerator pedal is manipulated during the run mode; verifying that the direction switch is in the reverse position when the accelerator pedal is manipulated; changing the run mode into a quick test mode when the direction switch is in the reverse position; and maintaining the run mode when the direction switch is in the forward position.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure as illustrated in the written description and claims hereof, as well as the appended drawings.
REFERENCES:
patent: 4517645 (1985-05-01), Yuki et al.
Cuchlinski Jr. William A.
Daewoo Heavy Industries Ltd.
Hernandez Olga
Staas & Halsey , LLP
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