Data processing: generic control systems or specific application – Specific application – apparatus or process – Mechanical control system
Reexamination Certificate
2000-05-05
2002-10-15
Chilcot, Richard (Department: 3627)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Mechanical control system
C702S113000, C033S203120
Reexamination Certificate
active
06466845
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to automotive assembly methods and, more particularly, to a method for tracking critical wheel alignment variables.
BACKGROUND ART
In order to remain successful, any industry that produces consumer goods must constantly monitor the quality of their products. If the actual or perceived quality of a product is lower than customer expectations, then the customer will find alternative producers of a similar, better quality product. Therefore, it is in the best interest of producers of consumer goods to constantly strive to improve the quality of their products.
Unfortunately, the way in which each consumer perceives quality may vary. Producing a product that fulfills a function without needing repair is only the first step in satisfying today's modern consumer. While designers are successful at making products whose subjective characteristics are perceived by consumers as high quality, it is more difficult to design a product whose objective characteristics are perceived in that same way. For example, the size, weight, or functions of a product are all easily measured and designed into a product; however, the vibrations produced, or color of a product are more subjective. Also, what may seem acceptable to a designer often may not be acceptable to a consumer.
One of these subjective characteristics noticeable to consumers is wheel alignment in an automobile. Wheel alignment is a major source of customer complaints. Unfortunately, prior art solutions have generally relied on manually tracking a limited number of critical characteristics with little success. Vehicle wheel alignment is very important for customer satisfaction. In order to insure proper performance of a vehicle, such as an automobile or truck, various inclination angles, such as toe, camber, caster and kingpin inclination angles are set on the vehicle wheels.
During the process of building a vehicle, a number of vehicles are selected and measured to determine the performance of the plant at aligning the vehicle wheels. Hundreds of characteristics relating to wheel alignment may be measured. Unfortunately, an individual operator can only track, chart and maintain a limited number of these characteristics.
In the past, an operator would audit the wheel alignment on approximately 1.9 percent of the vehicles produced by an assembly plant. The operator would then write down the data from each vehicle audited and plot the data on a wall chart and continuously calculate process capability parameters.
The operator only has time to track a limited number of critical wheel alignment variables. This results in a large amount of variation in some parameters of the process.
The disadvantages associated with conventional characteristic tracking techniques have made it apparent that a new technique for tracking critical wheel alignment variables is needed. The new technique should be able to automatically detect wheel alignment characteristics without significant labor involvement. The new technique should also automatically track all available critical wheel alignment characteristics.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved and reliable means for tracking critical wheel alignment variables. Another object of the invention is to automatically detect wheel alignment characteristics without significant labor involvement.
In accordance with the objects of this invention, an improved method for tracking critical wheel alignment variables is provided. In one aspect of the invention, a method for tracking critical wheel alignment variables begins by assembling a plurality of vehicles and performing a wheel alignment on each of these vehicles. To insure that wheel alignment is being performed properly, approximately two percent the vehicles are audited after production to verify correct wheel alignment. A plurality of significant wheel alignment characteristics for the audited vehicles are automatically collected and transferred to a database. These characteristics are then automatically plotted and reviewed on a real time basis to identify any negative trends. If a negative trend is identified, then a corrective action to correct this negative trend is implemented.
The present invention achieves an improved and reliable means for tracking critical wheel alignment variables. Also, the present invention is advantageous in that it automatically tracks all available critical wheel alignment characteristics.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5150515 (1992-09-01), Merrill et al.
patent: 5583797 (1996-12-01), Fluegge et al.
patent: 5812256 (1998-09-01), Chapin et al.
patent: 6151562 (2000-11-01), Merrill
Keener Brian T.
Kiafoulis Harry N
Chilcot Richard
Ford Motor Company
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