Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Reexamination Certificate
1998-09-28
2001-04-03
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
C701S035000
Reexamination Certificate
active
06212449
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates in general to materials handling vehicles and, more particularly, to diagnosing and repairing such vehicles. While the present invention is generally applicable to materials handling vehicles, it will be described herein with reference to a rider reach fork lift truck for which it is particularly applicable and for which it is initially being utilized.
Materials handling vehicle repairs and service have conventionally been handled by trained personnel who are familiar with vehicles in need of diagnosis and repair. Control systems in these vehicles may generate an event code prior to being shut down to prevent possible damage to the vehicle due to a fault. Trained repair personnel were then faced with a dead vehicle with no information regarding the fault or, at best, were provided with an event code which identified the general area of the vehicle wherein a fault had occurred. Armed with this knowledge of the vehicle, and possibly the general direction provided by conventional event codes, the repair personnel would make reference to a detailed service manual to repair the faults.
While some repair personnel are very highly skilled and are able to quickly diagnose and repair faults in material handling vehicles under these circumstances, many other less skilled and less experienced repair persons are not. Repair persons of all skill levels can become extremely frustrated when faced with little, if any, clue as to a potential fault and a vast amount of general information about the vehicle which contains a solution to the fault but no way to effectively identify that solution. What has been experienced in the field in response to such frustration is resort to what may be referred to as “swaptronics”, i.e., switching out components until a fault component, if any, is finally replaced to return the vehicle to service.
When swaptronics is employed, particularly in modern materials handling vehicles which include one or more computers or “black boxes”, all too commonly a computer, probably one of the more expensive system components, is first replaced to be sure that it is not the cause of the fault since historically it was the most difficult to diagnose. If not the problem, additional components also end up being replaced resulting in large quantities of fault free components being replaced, possibly under warranty, with resultant costs and lost time both for the service person and the down time of the vehicle. In addition to the high relative cost of computer components, replacement of a computer is often a more difficult task than replacement of components driven by the computer which components have proven much more likely to be the cause of a fault than the computer.
Accordingly, there is a need for an improved arrangement for diagnosing and repairing faults which occur in materials handling vehicles. Such an improved diagnostic arrangement should make diagnosis and repair less dependent on the experience and skill level of a repair person by leading the repair person step-by-step through a diagnostics procedure to accurately identify the cause of a fault and enable the repair person to make a repair without replacement of properly functioning components. Preferably, such an improved diagnostic arrangement would follow a set procedure regardless of the location of faults which need to be corrected with the procedure not only leading the repair person to faulty components but clearly indicating the identity and location of those components on the vehicle through directions, maps and component identification labeling. In addition, the directions, maps and component identification labels should be provided to the service person as needed in the diagnostic process, i.e., information is provided to the service person on-time, rather than being presented as a mass of information which can overwhelm, frustrate and delay diagnosis and repair.
SUMMARY OF THE INVENTION
This need is met by the invention of the present application wherein a diagnosis system leads service personnel step-by-step through diagnosis and repair of faults which might occur in a materials handling vehicle. Possible faults within a vehicle are assigned to status or event codes which correspond one-to-one with the faults. Accordingly, when a fault is detected, its corresponding event code is generated and displayed to the operator of the vehicle as well as being stored in a history of logged events.
The event codes uniquely identify systems of the vehicle in which faults have occurred by having the event codes for a given vehicle system all start with the same number, e.g., 2XX codes indicate faults in the hydraulic system of the vehicle, 3XX codes indicate faults in the traction/braking system of the vehicle. Thus, from the event code alone the operator knows what system will need to be diagnosed/repaired, what tools and probable parts will be needed. The event code is then used to access diagnosis information which more specifically indicates the portion of the vehicle wherein the malfunction has occurred, the components which caused the fault and, preferably, provides a pictorial depiction of that portion of the vehicle to familiarize the technician with the locations and identifications of the components.
The technician then advances to the portion of the vehicle containing the fault and opens that portion of the vehicle to display another pictorial depiction of the components of that portion of the vehicle. All components are marked within the vehicle by identifiers which are consistently used throughout the diagnostic information, pictorial representations and service manuals to reduce confusion and facilitate location of components, diagnosis and repair of the components.
The diagnostic information then tells the technician what to do to diagnose the components to determine whether they are faulty and must be replaced or whether the components are functioning properly. The diagnosis is preformed using the electronic control system of the vehicle with the technician being able to configure the electronic control system of the vehicle to monitor inputs to and outputs from the electronic control system and to apply limited duration full power test signals to components to be tested. The electronic control system inputs and outputs can be monitored while operating the vehicle in a normal manner. But when limited time duration, full power tests are performed, normal vehicle operation is inhibited.
The diagnostic information is configured so that testing is done from the end of control paths back to the controller, i.e., controlled or signal generating components such as solenoids, relays, switches, potentiometers and the like are first tested to ensure that they are not faulty; next, circuitry interconnecting those components to the electronic control system is tested; and, finally if no faults are found in the peripheral elements of the system, modules of the electronic control system are suspect in causing faults.
It is, thus, an object of the present invention to provide an improved diagnostic system for a materials handling vehicle which guides service technicians step-by-step through the diagnostic procedures to remove frustration from the diagnostic process; to provide an improved diagnostic system for a materials handling vehicle wherein an electronic control system of the vehicle is used to monitor inputs to and outputs from the control system for diagnosing faults; to provide an improved diagnostic system for a materials handling vehicle wherein an electronic control system for the vehicle is used to provide limited time, full power test signals for components suspected of causing a malfunction within the vehicle; and, to provide an improved diagnostic system for a materials handling vehicle wherein service technicians are guided step-by-step through a diagnosis procedure which initially diagnoses and tests components which are at the end of control loops extending from an electronic control system, then circuitry interconnecting those component
Gaskell James W.
Meiring Donald T.
Wellman Timothy A.
Crown Equipment Corporation
King & Schickli PLLC
Nguyen Tan
LandOfFree
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