Programmable service reminder apparatus and method

• US 4,613,939 A
• Filed: 08/08/1984
• Issued: 09/23/1986
• Est. Priority Date: 08/08/1984
• Status: Expired due to Fees

• Current Assignee: Caterpillar Industrial Incorporated Mentor Ohio
• Original Assignee: Caterpillar Industrial Inc (Caterpillar Incorporated)
• Inventors: Paine, John C.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US06/638,922
• Time in Patent Office: 776 Days
• Field of Search: 364/424, 364/550, 364/551, 364/569, 377/20, 340/52 R, 340/52 F
• US Class Current: 701/35
• CPC Class Codes: G07C 5/006 Indicating maintenance

Abstract

Electronic hourmeter devices having service reminders are useful, for example, in industrial vehicles. Advantageously, such service reminders should be field programmable for a variety of predetermined service intervals. The subject electronic service reminder is readily field programmable by authorized personnel and is protected from being programmed or reset by unauthorized personnel. A service status indicator is activated in response to the elapsed hourmeter time exceeding the programmed service interval time, and both the hourmeter elapsed time and the service reminder programmed time are resettable in response to a predetermined magnetic flux applied to respective Hall effect switches. Data is advantageously maintained in a non-volatile memory device without need for a battery back-up.

Claims

1. A programmable service reminder apparatus for a vehicle, said vehicle being controllably energizable from a vehicle power source, comprising:

sensor means for producing a control signal in response to said vehicle being energized;

clock means for producing a periodic time base signal;

service status indicator means for signaling an elapsed period of time;

first switch means for producing a service time reset signal;

programmable memory means for receiving and storing data; and

,

processor means for receiving said control signal, said periodic time base signal and said service time reset signal;

repeatedly producing an incremental elapsed time signal in response to receiving said control signal and said periodic time base signal and periodically storing the instant elapsed time signal to said programmable memory means;

sequentially producing a plurality of discrete predetermined service time signals in response to receiving said service time reset signal, the number of said predetermined service time signals produced being responsive to the period of time said service time reset signal is continuously received, combining the last stored elapsed time signal and the last produced predetermined service time signal to form a combined time signal, and responsively storing said combined time signal to said programmable memory means; and

repeatedly comparing the instant elapsed time signal and said stored combined time signal and energizing said service status indicator means in response to the instant elapsed time signal being greater than said stored combined time signal.

2. A programmable service reminder apparatus, as set forth in claim 1, wherein said first switch means includes magnetic flux responsive means for producing said service time reset signal in response to a predetermined magnetic flux field.

3. A programmable service reminder apparatus, as set forth in claim 2, wherein said magnetic flux responsive means includes a Hall effect switch.

4. A programmable service reminder apparatus, as set forth in claim 3, including second switch means for producing an elapsed time reset signal, said second switch means including a Hall effect switch, and wherein said processor means deenergizes said service status indicator means in response to receiving said elapsed time reset signal.

5. A programmable service reminder apparatus, as set forth in claim 1, wherein said programmable memory means includes a non-volatile random access memory device.

6. A programmable service reminder apparatus, as set forth in claim 5, wherein said service time signals are gray coded digital numbers stored in said non-volatile random access memory device.

7. A programmable service reminder apparatus, as set forth in claim 1, wherein said processor means deenergizes said service status indicator means in response to receiving said service time reset signal.

8. A programmable service reminder apparatus for a vehicle, said vehicle being controllably energizable from a vehicle power source, comprising:

sensor means for producing a digital control signal in response to said vehicle being energized;

clock means for producing a periodic time base signal;

service status indicator means for signaling an elapsed period of time;

a first Hall effect switch adapted to produce a digital service time reset signal in response to being exposed to a predetermined flux field;

programmable memory means for receiving and storing digital data; and

,

processor means for receiving said digital control signal, said periodic time base signal and said digital service time reset signal;

repeatedly producing an incremental digital elapsed time signal in response to receiving said digital control signal and said periodic time base signal and periodically storing the instant digital elapsed time signal to said programmable memory means;

deenergizing said service status indicator means and sequentially producing a plurality discrete of predetermined digital service time signals in response to receiving said digital service time reset signal, the number of said predetermined service time signals produced being responsive to the period of time said service time reset signal in continuously received, combining the last stored digital elapsed time signal and the last produced predetermined digital service time signal to form a combined digital time signal, and responsively storing said combined digital time signal to said programmable memory means; and

repeatedly comparing the instant digital elapsed time signal and said stored digital combined time signal and energizing said service status indicator means in response to the instant elapsed time signal being greater than said stored combined time signal.

9. The method for controllably operating a programmable service reminder apparatus associated with a vehicle, said vehicle being controllably energizable from a vehicle power source, comprising the steps of:

producing a control signal in response to said vehicle being energized;

producing a periodic time base signal;

controllably producing a service time reset signal;

receiving said periodic time base signal and said service time reset signal;

repeatedly producing an incremental elapsed time signal in response to receiving said control signal and said periodic time base signal;

periodically storing the instant elapsed time signal to a programmable memory means;

sequentially producing a plurality of discrete predetermined service time signals in response to receiving said service time reset signal, the number of said predetermined service time signals produced being responsive to the period of time said service time reset signal is continuously received, combining the last stored elapsed time signal and the last produced predetermined service time signal to form a combined time signal, and storing said combined time signal to said programmable memory means;

repeatedly comparing the instant elapsed time signal and said stored combined time signal; and

energizing a service status indicator means in response to the instant elapsed time signal being greater than said stored combined time signal.