The present invention relates to a work fixing device, more specifically a work fixing device for gripping a work with circular section inserted in a hole formed in the main body of the work fixing device, comprising a plurality of clamps disposed movably along a guide groove formed in the radial direction in the main body of the work fixing device; and a clamp moving mechanism for synchronously moving the plurality of clamps in the radial direction.
Conventionally, when executing processing such as spinning, cutting, etc. on works with circular section (also including hollow works in tubular shape, in this specification), a variety of work fixing devices are used (JP 07-227733 A, for example), because of the necessity of fixing the work.
By the way, this type of work fixing device usually comprises, as shown in FIG. 11, a clamp moving mechanism 3 for moving a plurality of clamps 2. However, with this arrangement, in which the clamp is supported and moved by the moving mechanism 3 disposed on either the back face or a side face of the clamp 2, the fixing of work was liable to be limited only to the central part of the work or biased to one side.
For that reason, in the case of a long work or a work of soft metal such as aluminum, etc. or a hollow work in tubular shape with little rigidity, or in the case where the dimensional accuracy is rather low and variable, there was a problem that the work cannot be fixed accurately, eventually having negative influences on the working accuracy and operating efficiency.