Supports – Brackets – Article holding means
Reexamination Certificate
1999-03-31
2001-07-31
Braun, Leslie A. (Department: 3632)
Supports
Brackets
Article holding means
C248S181200, C248S288510, C403SDIG001, C403S133000, C403S122000
Reexamination Certificate
active
06267341
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application relates generally to apparatus for supporting a complex part such as a stamped sheet metal inner door panel having compound curves in a fixed position for surface measurements without interference to measurement by clamps or fixtures which project from the surface. Basically, the subject apparatus provides a substantially clampless support arrangement to accurately secure a complex part for measurement by automatically controlled digital measuring equipment.
2. Background of the Invention
For monitoring stamping quality, the surface of a relatively complex automobile body part such as a vehicle inner door panel is digitally measured through digital electronic automation (DEA). The DEA process utilizes an automatic tracking device or coordinate measuring machine (CCM) to move an sensor in relation to a stamped part to be measured. The sensor is mounted upon an arm and is selectively moved to contact particular sites on a surface of the stamped part to generate digital measurement data. This digital data is received into a computer which is programmed to compare the measurements with a set of desired geometric dimensions and tolerances (GD & T).
It is important that a vehicle inner door panel is accurately produced as a vehicle door is a composite of at least an inner and an outer panel to produce the complete vehicle door. The outer panel is attached to the inner panel and how well the door fits in an opening in the vehicle body can be effected by the accuracy of the inner and outer door panels. Thus, both panels must be assembled and attached together in a manner to create a very accurate composite. Both the inner and the outer panel have a relatively complex shape with non-parallel curved surfaces. If the panels are inaccurately formed during the stamping operation, the resultant composite door may not accurately fit in the vehicle door opening or its exterior surface may not properly align with the adjacent surfaces of the other parts of the vehicle.
Currently, deviations from desired GD & T are uncovered by periodically measuring a sample door panel by the CMM. As previously mentioned, the CMM supports a surface measuring sensor, essentially a very accurate switch. Such a sensor which is currently used to measure surfaces is manufactured by Renishaw in the United Kingdom, Model K60606. As the CMM moves the sensor, it measures various selected surface sites on the stamped part and feeds the data into the associated computer in digital format. The computer is programmed to receive the data and compare it with the GD & T to determine whether the part is within desired specifications and tolerances.
However, before measurements can be taken and data generated, the sample stamped part must first be accurately positioned in a desired orientation and then accurately held in that position during the measurement process. Thus, before using the CMM to take measurement data, a plurality of adjustable support columns (usually four or five) are very accurately positioned. The support columns support the stamped part to be measured which is laid over the support columns. When the columns are properly adjusted in a vertical direction, the stamped part is rigidly supported but must be restrained against the upper ends of the columns to prevent movements. Currently, clamps are used to hold a stamped part against the upper end of the columns. A typical clamp has a U-shaped configuration allowing it to extend around the edge portion of the stamped part. This unfortunately also places a portion of the clamp over a portion of the surface to be measured with a portion projecting upwardly from the surface. This upwardly projecting portion of the clamp usually will interfere with the movement of the sensor. In fact, measurements adjacent the clamp are usually impossible without first reclamping the part away from the desired measurement area and then removing that clamp that interferes with the desired measurement. In addition, unless very carefully regulated, an excess force can be placed on the stamped part by the clamp which can cause distortion of the part and resultant inaccuracies in surface measurement.
SUMMARY OF THE INVENTION
A primary object of the subject application is to eliminate or significantly reduce the necessity for use of clamps in the above described DEA surface measuring process. Accordingly, the subject application presents a clamp replacement in the form of a magnetic swivel datum (MSD) pad or mount. An MSD is attached to the upper end portion of the aforedescribed support column and is constructed to provide a versatile support for an angulated or irregular surface of a stamped part. Specifically, the MSD pad utilizes a ball type connection to accommodate angulated surfaces of a stamped part and secure it to the column without any upwardly projecting portions which could interfere with a measurement by the CMM sensor.
Specifically, the MSD pad comprises a short support shaft having a substantially spherical upper end portion which is partially encapsulated in a pad part. The pad part is pivotally movable about the spherical end portion but is accurately fixed to the shaft. This allows a flat top surface of the pad to adjust to any angulated surface of a stamping. The short support shaft is insertablely mounted in a recess of a column support which was previously identified. Countersunk in the flat top surface of the pad is at least one magnet so that the surface of the magnet is flush with the surface. Resultantly, when a steel inner door panel, for example, is positioned in overlying relationship to the flat surface of the pad, a magnetic force restrains the panel from movements.
The MSD described above permits the placement of the part onto the upward facing surface of the base while magnetic force secures the part to the MSD and the support column without the necessity of providing a clamp which typically extended upwardly from the surface of the part which undesirably interferes with the previously described DEA measurement process.
REFERENCES:
patent: 4986689 (1991-01-01), Drutchas
patent: 5580121 (1996-12-01), Dange et al.
patent: 5704582 (1998-01-01), Golembiewski et al.
patent: 5857815 (1999-01-01), Bailey et al.
patent: 5993212 (1999-11-01), Shiner
patent: 6010271 (2000-01-01), Jackson et al.
Fleming Todd J.
Husulak George
Ponagajba Donald J.
Rekar Robert S.
Baxter Gwendolyn
Braun Leslie A.
Calcaterra Mark P.
DaimlerChrysler Corp.
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