| 摘要 |
The device comprises a guiding piece (1), the upper part of which is of profiled construction. The two lateral surfaces (14, 15) of the beam-shaped guiding piece (1) are provided in the region of its top corner parts with channels (17, 18). A guided piece (2), in the underside of which a groove (25) is executed, is positioned on the guiding piece (1). One of the lateral walls (30) of this groove (25) is undercut and is in engagement with the flank (19) of one of the channels (17) of the beam (1). The opposite lateral wall (32) of the groove (25) stands approximately at right angles to the bottom (33) of the groove (25). A cavity, in which a pawl (4) is located, is executed in this portion of the guided piece (2). This pawl (4) is connected by means of a screw (6) to the guided piece (2), a nose (35) of the pawl (4) engaging the other channel (18) of the beam (1). In such a device, the guided piece can be placed upon the guiding piece at any point of the latter. The position of the support surface for the workpiece can be finely adjusted and/or levelled. The contact surfaces between the guiding piece and the guided piece are constructed and dimensioned so that, after the guiding piece has been introduced into the guided piece, this structure cannot collapse under the influence of the deadweight of these parts, even if the pawl of the holding device has not been tightened.
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