Microdistancer

Abstract

A precision rangefinder, including a threaded measuring rod supported in a casing and a detection mechanism for detecting the rotational movement of the measuring rod. The detection mechanism includes a fixed detection element and a movable detection element, wherein the fixed detection element does not move relative to the casing, and the movable detection element It is fixed on the measuring rod and can rotate together with the measuring rod. There is a gap of predetermined width between the two detection elements. The instrument also includes a drive and guide mechanism that transmits the rotational movement of the measuring rod to the movable detection element and guides the relative translational movement therebetween. The driving and guiding mechanism includes a guiding sleeve, which can be fixed on the movable detection element to rotate with it and is provided with an inner groove extending parallel to the measuring axis. Also included is a guide attached to the stem for rotation therewith, shaped and dimensioned to conform to the inner groove and movably extending therein. A setting mechanism can also be provided to set the gap width between the detection elements as required.

Description

technical field [0001] The invention relates to a precision distance measuring instrument which can constitute an electronic micrometer. Background technique [0002] Precision measuring instruments known as threaded micrometers or micrometers, comprising threaded rods, are known in practice. The stem is screwed into a screw-in sleeve secured to the micrometer housing. The cylindrical part of the stylus protrudes from the housing and has at its free end an axial end face serving as a measuring face. The casing has an L-shaped ruler frame, and a datum plane aligned with the measuring rod is arranged on the ruler frame. The datum is the datum of the plane. The stem can be turned manually by means of a roller handle fixed at the end of the stem facing away from the measuring surface. In this way, the measuring rods can be moved synchronously in the direction of the axis of rotation. [0003] Micrometers are used in work and production practice to measure workpieces or othe...

AI Technical Summary

Problems solved by technology

[0006] In addition, it has been found that the guide mechanism consisting of a V-groove and threaded pin with a conical tip significantly affects the measuring accuracy

Alignment and depth deviations that inevitably occur when grinding V-grooves lead to changes in the mutual position of the two detection elements and thus to measurement errors

However, it is very difficult to form grooves on the outer surface of the measuring sleeve in a precise manner, perfectly parallel to the axis of rotation and of constant depth

[0007] Also, the grooves must be ground with abrasive discs with a very small outer diameter; such discs have a short service life, making the tool more expensive and thus increasing production costs

It was also found to be a disadvantage that only the conical tip of the screw can be used as the final joint surface for the end of the measuring range

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