Metal fusion bonding – Process – With condition responsive – program – or timing control
Reexamination Certificate
1998-05-12
2001-01-16
Ryan, Patrick (Department: 1725)
Metal fusion bonding
Process
With condition responsive, program, or timing control
C228S103000, C219S158000, C219S121630
Reexamination Certificate
active
06173882
ABSTRACT:
This invention relates generally to workpiece processing, and more particularly to the adjustment of clamps used to hold a workpiece in position during welding.
BACKGROUND OF THE INVENTION
The door of an automotive vehicle typically consists of an inner panel and an outer panel, both made of a resilient metal such as steel. The panels are preliminarily held together by overlapping flanges along the edges and then welded together at a welding station where the door is retained in a fixed position by several clamps.
It is essential that the door be held correctly without bending or flexing the panels, so that the geometry of the door is right for welding. Otherwise, when released after welding, the door may spring-back to a slightly warped condition. This may prevent the door, when installed in a vehicle, from sealing properly against the frame, producing wind noise, water leaks and an unsightly appearance. To eliminate the problem, the clamps used to hold the door during welding, or at least some of the clamps, must be adjusted. In the past, it has been necessary to make the adjustment manually by shimming the clamps. The operator made this adjustment based on his experience and judgment. This was very time-consuming and subject to error.
SUMMARY OF THE INVENTION
In accordance with the present invention, each clamp is mounted on a slide and can be adjusted back and forth along the slide by a motor. In practice, a workpiece such as a vehicle door is placed at the weld station on support pads and gripped by the clamps. After welding, the door is moved to a checking station where critical points on the door are measured. These measurements are preferably taken by laser optic cameras.
The measurement data is transmitted to a central processing unit (CPU) at an optical station where it is stored in a computer. The measurement data is then compared with ideal or “nominal” critical point locations to determine the error if any, that is, the departure of the measurement data from the ideal. If the departure or error is outside the maximum tolerance, the CPU will interpolate the data with an algorithm and determine the amount of clamp adjustment needed.
In an automatic system, the adjustment data is transmitted from the CPU to a servo-motor controller to actuate the motors to make the necessary adjustment in the position of one or more of the clamps. In a manual system, the CPU will merely record the error which an operator will interpret and then manually input the adjustment to the servo-motor controller. The adjustment can be made rapidly and with a high degree of accuracy. The adjustment causes one or more clamps to bend the workpiece into a profile or shape which corresponds to a preferred or ideal shape. The workpiece is then welded while held in this ideal profile.
One object of the invention is to provide method and apparatus for quickly and accurately adjusting the positions of clamps used to hold a workpiece during processing, having the foregoing features and capabilities.
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Booker Kenneth
Dunneback Mark R.
Guerra Joseph
Mu Lianchun
Nartey Enoch
Chrysler Corporation
Newsome Cecilia
Ryan Patrick
Shurupoff Lawrence J.
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