JPH044178Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protractor for a surveying instrument in which a synthetic resin scale member having an angular scale is fixed around a metal ring member.

In an example of the conventional protractor for a surveying instrument, the scale member is configured as an annular member without any notches or through holes. This protractor has the advantage that it can obtain smooth rotational movement by making sliding contact between the metal and the rotation center axis of the survey instrument body, and that the angle scale can be easily provided on the synthetic resin member. has. On the other hand, when using the above-mentioned conventional protractor in an extremely cold region, a difference in the expansion coefficients of metal and synthetic resin causes a difference in the amount of contraction between the metal and synthetic resin. There was a problem with cracks forming.

The purpose of this invention is to provide a protractor for surveying instruments that solves the above conventional problems.
Its structural feature is that it is a protractor for a surveying instrument in which a synthetic resin scale member having an angular scale is fixed to the outer periphery of a metal environmental material. This is because a plurality of through parts are provided on the same circumference of the scale member.

Therefore, even if a surveying instrument incorporating a protractor according to the present invention is used in an extremely cold region, problems such as cracks in the synthetic resin scale member will not occur.

Embodiments of the present invention will be described below based on the drawings. As shown in FIG. 1, a surveying instrument 1 such as a level includes a telescope 4 consisting of an objective lens 2 and an eyepiece 3, a focusing knob 5 rotatably attached to the side wall of the telescope, and a telescope. Base part 6 integrated with telescope 4
A circular bubble tube 7 is attached to protrude from the bubble tube, a reflecting mirror member 8 is attached to the top of the optic telescope 4 for observing the circular bubble tube 7 from the horizontal direction, and a reflecting mirror member 8 is attached to the top of the optic telescope 4 to orient the optic telescope 4 generally in the optic direction. Sighting device 9,
A tripod mount 10 for attaching the surveying instrument 1 to a tripod (not shown), three horizontal adjustment knobs 11 (only two are shown) for adjusting the inclination of the base 6 with respect to the tripod mount 10, and a viewing angle. An angle scale 1 arranged at the bottom of the base 6 to indicate the viewing direction of the telescope 4
It has a horizontal adjustment knob 14 for rotationally adjusting the reference plate 6, that is, the optic telescope 4, in the horizontal direction with respect to a member substantially integral with the protractor plate 13 and the tripod stand 10.

An index 15 for an angle scale 12 is provided at the lower part of the base portion 6, and the angle of the optic direction of the optic telescope 4 is read by this and the angle scale 12. As shown in FIG. 2, the first embodiment of the protractor 13 includes a metal ring member 20 that is slidably fitted to the shaft member of the surveying instrument 1 (not shown), and a metal ring member 20 that is attached to the outer circumference of the metal ring member 20. It consists of a fixed synthetic resin scale member 21. The scale member 21 is generally composed of a bottom portion 22 and a cylindrical portion 23, and the cylindrical portion 23 is provided with an angle scale 12. On the other hand, the bottom portion 22 is provided with a plurality of notches 24 on the inner circumferential portion in contact with the metal ring member 20, and as a result, the metal ring member 20 and the synthetic resin scale member 21 have a plurality of small-area contact portions 25. It is integrated through

In the configuration of the first embodiment described above, the protractor 1
3 is placed under low temperature conditions such as in extremely cold regions, and even if a difference in shrinkage appears between the metal ring member 20 and the synthetic resin scale member 21, the difference in shrinkage is absorbed by the deformation of the notch 24 etc. There is no possibility that cracks will occur in the scale member 21 or that the angle scale 12 will become inaccurate.

A second embodiment of the protractor 13 is shown in FIG. 3, and the same components as those in the first embodiment are given the same reference numerals and their explanations will be omitted. In addition to the notch 24, a plurality of through holes 30 are provided on the same circumference in the bottom surface 22 of the synthetic resin scale member 21.

In the second embodiment described above, the bottom part 22 is easily deformed, and the difference in shrinkage between the metal ring member 20 and the synthetic resin scale member 21 that occurs under low temperature conditions can be absorbed by the first This can be carried out more efficiently than in the embodiment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the surveying instrument, FIG. 2 is a perspective view of the protractor of the first embodiment, and FIG. 3 is a perspective view of the protractor of the second embodiment. 1... Survey instrument, 2... Objective lens, 3... Eyepiece, 4... Telescope, 7... Circular bubble tube,
12... angle scale, 13... protractor, 15... index, 20... metal ring member, 21... synthetic resin scale member, 24... notch, 26... leg,
30...Through hole.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a protractor for a surveying instrument in which a synthetic resin scale member having an angle scale is fixed to the outer periphery of a metal environmental material, the angle scale is centered at the center of the angle scale. A protractor for a surveying instrument, characterized in that a plurality of through parts are provided on the same circumference of the scale member. (2) Utility model registration claim 1, wherein the penetrating portion is a notch provided on the inner periphery that contacts the metal ring and forms a space between the metal ring and the synthetic resin scale member. A protractor for surveying instruments as described in . (3) Utility model registration claim 1, wherein the through part is a through hole provided in the middle part of the scale member and forming a space in the synthetic resin scale member.
A protractor board for surveying instruments as described in section.