Geometrical instruments – Gauge – With support for gauged article
Reexamination Certificate
2002-08-30
2004-06-01
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
With support for gauged article
C033S552000
Reexamination Certificate
active
06742273
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a workpiece measuring apparatus for measuring at least one of a size and a shape of a workpiece.
2. Description of the Related Art
When a workpiece has been machined in a machine tool, the size or the shape of each portion of the machined workpiece is generally measured in the inspection process in order to check that the workpiece size obtained is suitable or to obtain feedback on the result of the machining. Especially in a turning or grinding process system, such as a grinding machine or a machining center, the size of the workpiece obtained by the machining process may change irregularly due to chipping of a tool, etc. and, therefore, the in-line or on-line inspection of a machined workpiece is often carried out.
In view of the recent remarkable progress of the machining speed of the machine tools, the throughput of a production line as a whole is dependent greatly on the throughput of the inspection process in the case where the in-line or on-line inspection is carried out as described above. Consequently, the workpiece measuring apparatus is required to measure the size or the shape of a workpiece rapidly.
On the other hand, a high dimensional accuracy has recently been required for a plurality of points of a machined part and, to meet this requirement, the workpiece measuring apparatus is required to have a high measurement accuracy for a plurality of points.
In order to meet these requirements, the conventional workpiece measuring apparatus is adapted to include a plurality of measuring gauges at fixed positions so that it can realize a high measurement accuracy and a high throughput by specializing each of the measuring gauges for the measurement of a specific portion of a workpiece having a specified shape and thereby limiting the measurable dimensional range to improve the measurement accuracy while, at the same time, making it possible to simultaneously measure different portions of a workpiece with a plurality of measuring gauges.
With the conventional workpiece measuring apparatus, however, the fact that the measuring gauges are fixedly arranged makes it difficult to change or add measurement positions in keeping with a change in the shape to which the workpiece is to be machined. Further, in view of the fact that the measurable dimensional range of each measuring gauge is limited, it is difficult even to follow the change in the size of the machined workpiece in versatile way. As a result, when the production line is changed, due to a change in the product design, a workpiece measuring apparatus is often required to be newly designed and developed.
Further, in the case where a recessed groove is formed in the outer peripheral surface of the workpiece together with the workpiece shape change, the conventional workpiece measuring apparatus poses the problem that the gauge head (i.e. the detector) of the measuring gauge is often trapped in the groove, thereby making it impossible to measure the outer peripheral size of the portion of the workpiece free of the groove. This is also the case with a workpiece having a hole of which the inner peripheral surface is formed with a recessed groove.
Also, the tool can be chipped off during the machining process, especially in the turning process, resulting in an excessively large machined workpiece. In the measuring gauge of a type in which the workpiece is measured by being arranged between two gauge heads, such an excessively large workpiece conveyed to the measurement position of the workpiece measuring apparatus would cause a problem of an interference with the two gauge heads and their resultant breakage.
SUMMARY OF THE INVENTION
Therefore, an object of the invention is to provide a workpiece measuring apparatus which can flexibly respond to a change in the production line due to a change in the product design.
Another object of the invention is to provide a workpiece measuring apparatus capable of measuring the size of that portion of the outer peripheral surface of a workpiece or that portion of the inner peripheral surface of a hole of a workpiece which is not formed with a recessed groove, even in the case where the workpiece or the hole thereof, as the case may be, is formed with such a recessed groove.
Still another object of the invention is to provide a workpiece measuring apparatus which can prevent gauge heads of a measuring gauge unit being broken even in the case where a workpiece larger than the measurable dimensional range of the measuring gauge unit is conveyed to a measurement position of the workpiece measuring apparatus.
According to the present invention, there is provided a workpiece measuring apparatus, for measuring at least one of a size and a shape of a workpiece, which includes:
a machine base;
a column mounted on the machine base and having a mounting mechanism on at least one of the side surfaces of the column;
a measuring gauge unit removably fixed at an arbitrary position on the mounting mechanism of the column; and
a conveying unit for conveying a machined workpiece to a measurement position where a measurement can be performed by the measuring gauge unit.
A plurality of measuring gauge units may be removably mounted independently of each other at arbitrary positions on the mounting mechanism.
Preferably, the mounting mechanism includes one or more guide grooves, and the measuring gauge unit includes one or more sliding elements, the sliding element adapted to slidably engage in the guide groove.
Preferably, the machine base includes a support portion and a base plate removably mounted on the top of the support portion, and a plurality of different mounting sites for mounting the column thereon are formed on the base plate, the column being removably fixed on the base plate.
In similar way, preferably, the measuring apparatus further includes an operation panel for an operator to control the operation of the measuring gauge unit and the conveying unit; the machine base includes a support portion and a base plate removably mounted on the top of the support portion; and a plurality of different mounting sites for mounting the operation panel thereon are formed on the base plate, the operation panel being removably fixed at one of the mounting sites on the base plate.
Preferably, the base plate is formed with an opening, and when an additional measuring gauge unit is disposed in the machine base, the additional measuring gauge unit can measure at least one of the shape and the size of the workpiece positioned above the base plate through the opening.
The workpiece measuring apparatus further includes an additional column formed with a mounting mechanism, the additional column being mounted on the column.
According to a preferred embodiment, when it is determined that at least one of a size of an outer peripheral surface of the workpiece and a size of an inner peripheral surface of a hole of the workpiece is out of a predetermined range, the workpiece is rotated and the measuring gauge unit thereafter measures at least one of the size of the peripheral surface of the workpiece and the size of the inner peripheral surface of the hole of the workpiece again.
In this case, for example, the conveying unit includes a guide unit mounted on the base plate and a workpiece mount rotatable about a rotational axis extending vertically and movable along the guide unit, and when a measured size of at least one of an outer peripheral surface of the workpiece and an inner peripheral surface of a hole is out of a predetermined range, the workpiece mount is rotated and the size of at least one of the outer peripheral surface of the workpiece and the inner peripheral surface of the hole of the workpiece is thereafter measured again.
According to another preferred embodiment, the measuring gauge unit includes an interference prevention plate, the interference prevention plate having a cutoff adapted to receive a workpiece smaller than a predetermined tolerable size when the workpiece moves to the measurement position, and when
Kamiya Mamoru
Kawasaki Yoichi
Nagatsuka Shinji
Christie Parker & Hale LLP
Fulton Christopher W.
Tokyo Seimitsu Co. Ltd.
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