JPH05223571A - Horizontal axis structure of survey machine - Google Patents

Abstract

PURPOSE:To improve altitude angle measurement by suppressing backlash in thrust direction and that in radial direction of a horizontal axis of a survey machine. CONSTITUTION:A collar part 8 is provided at the edge part of a horizontal axis 2 where an altitude scale board 10 is sealed, the inner-periphery surface of a bearing 6 which supports the horizontal axis 2 is formed in a taper, and then a plurality of bearing balls 11 are laid out between the taper surface 6a and the collar part 8. A press mechanism 12 which constantly applies a load to the end face of the horizontal axis 2 in axial direction is mounted within a post 4. A spring holder 13 which opposes an end face 2a of the horizontal axis 2 is fixed into the post 4 as a press mechanism 12, a winding spring 14 is housed within the spring holder 13, at the same time a ball support 15 is housed so that it can slide freely, and then a conical recess 15a is provided on the tip surface of the ball support 15. A steel ball 16 is laid out between the recess 15a and the end face 2a of the horizontal axis 2 and a mechanism for applying the load of the winding spring 14 to the end face 2a of the horizontal axis 2 through the steel ball 16 is adopted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal axis structure of a surveying instrument, and more particularly to a horizontal axis structure of a surveying instrument such as a theodolite or a total station.

[0002]

2. Description of the Related Art In a surveying instrument such as a theodolite or a total station, as shown in FIGS. 3 and 5, horizontal axes 102 and 103 are provided on both sides of a telescope 101, and a bearing 107 is screwed to an inner wall of a hollow column 104 by a screw 107. 105 is fixed, and the horizontal shaft 102 is rotatably supported by the bearing 105. The horizontal shaft 103 is also supported by a bearing (not shown) fixed in the column 105. Also,
An advanced dial 110 is attached to the end surface of the horizontal shaft 102.

As shown in FIG. 4, a clearance 105a is provided on the inner peripheral surface of the bearing 105, and the horizontal shaft 102 falls into the clearance 105a due to the weight of the telescope 101 to stabilize the horizontal shaft 102. ..

Further, the collar portion 10 is provided at the center of the horizontal shaft 102.
9 is provided, and the collar portion 10 is provided at the end of the horizontal shaft 102.
8 is provided, and the bearing 105 is sandwiched between the two flanges 108 and 109 to suppress the play of the horizontal shaft 102 in the thrust direction.

[0005]

However, the bearing 105
When the lubricating oil wraps around the escape 105a, the horizontal shaft 102 is lifted, and the altitude dial 110 is eccentric.

Further, the backlash in the thrust direction of the horizontal shafts 102 and 103 is suppressed to 0.0 mm by precision processing, but the focus difference in the optical reading device or the encoder signal in the electronic reading device is not detected. In order to reduce stability and achieve more accurate angle measurement, suppression of thrust play has still been insufficient.

The present invention has been made in view of the above circumstances, and its object is to suppress the backlash in the radial direction and the thrust direction of the horizontal axis and to provide a horizontal surveying instrument capable of performing more accurate angle measurement. It is to provide a shaft structure.

[0008]

In order to solve the above-mentioned problems, the horizontal axis structure of a surveying instrument of the present invention is such that a bearing for rotatably supporting the horizontal axis of a telescope is fixed in a column, and the horizontal axis is attached to the horizontal axis. In the horizontal axis structure of the surveying instrument with the advanced scale plate fixed,
A thrust receiving surface is provided at an end of the horizontal shaft, an inner peripheral surface of the bearing that supports the horizontal shaft is tapered, and a plurality of bearing balls are arranged between the tapered surface and the thrust receiving surface. A pressing mechanism that presses the thrust receiving surface toward the taper surface by constantly applying a predetermined axial load to the horizontal shaft is installed in the column.

[0009]

As described above, since the pressing mechanism for pressing the thrust receiving surface toward the tapered surface by constantly applying the load in the predetermined axial direction to the horizontal shaft is installed in the support column,
The play in the thrust direction of the horizontal shaft is suppressed, and a thrust receiving surface is provided at the end of the horizontal shaft, and the inner peripheral surface of the bearing that supports the horizontal shaft is tapered, and between the tapered surface and the thrust receiving surface. Since a plurality of bearing balls are arranged in the center of the shaft, the pressing mechanism presses the horizontal shaft in the axial direction to activate the automatic centering function, and the center of the bearing and the center of the horizontal shaft are aligned. It is suppressed and the altitude dial is not eccentric.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a broken sectional view showing a horizontal axis structure of a surveying instrument according to an embodiment of the present invention. Horizontal axes 2 and 3 are provided on both sides of the telescope 1, and the horizontal axes 2 and 3 are columns 4 and 5.
Supported by. A bearing 6 is fixed to the inner wall of the column 4 with a screw 7, and the horizontal shaft 2 is rotatably supported by the bearing 6. Similarly, the horizontal shaft 3 is supported by a bearing (not shown) fixed to the inner wall of the column 5. A doughnut-shaped altitude scale 10 for measuring an altitude angle is adhered to the end surface 2a of the horizontal shaft 2, and the altitude scale 10 rotates together with the horizontal shaft 2. A brim 8 is provided at the end of the horizontal shaft 2.
However, a collar portion 9 is provided at the center of the horizontal shaft 2. The bearing 6 is sandwiched between the two brim portions 8 and 9.

The inner peripheral surface of the bearing 6 is formed in a tapered shape, and a plurality of bearing balls 11 are arranged on the tapered surface 6a, and the thrust receiving surface 8a of the horizontal shaft 2 is supported via the bearing balls 11. Has been done.

A scale reading device (not shown) for optically or electronically reading the advanced scale 10 is provided in the column 4.
And a pressing mechanism 12 for pressing the horizontal shaft 2 in the axial direction.

The scale reading device is fixed at a predetermined position in the column 4.

The pressing mechanism 12 has an end surface 2a of the horizontal shaft 2.
The cylindrical spring holder 13 is fixed to the inner wall of the support column 4 so as to face the central part of the column, the winding spring (spring) 14 is housed in the spring holder 13, and the cylindrical sphere support 15 is slid. This is a mechanism in which the ball support 15 is movably accommodated, a conical recess 15a is provided on the tip end surface of the ball support 15, and a steel ball 16 is disposed between the recess 15a and the end surface 2a of the horizontal shaft 2.

The load of the winding spring 14 of the pressing mechanism 12 is applied to the end face 2a of the horizontal shaft 2 via the ball support 15 and the steel ball 16 supported by the ball support 15, and the horizontal shaft 2 is always shown in FIG. It is biased to the right. As a result, the horizontal axis 2,
The backlash in the thrust direction of 3 is suppressed, the eccentricity error does not change, and the eccentricity once adjusted does not go wrong. As described above, the steel ball 16 is the conical recess 15a of the ball support 15.
Is supported by the steel ball 16, and the load of the winding spring 14 is applied to the end surface 2a of the horizontal shaft 2 through the steel ball 16.
Even if a force other than the axial direction acts on the steel ball 16,
Since the steel ball 16 rolls in the recess 15a, radial backlash of the horizontal shaft 2 does not occur, and only the axial force is always transmitted to the end surface 2a of the horizontal shaft 2.

On the other hand, as described above, the tapered surface 6a of the bearing 6 is used.
Since a plurality of bearing balls 11 are disposed between the horizontal shaft 2 and the flange portion 8 of the horizontal shaft 2, when the horizontal shaft 2 is pressed in the axial direction, an automatic centripetal function is activated and the center of the bearing 6 and the horizontal shaft 2 are engaged. The center of 2 is coincident with, the radial play of the horizontal axis 2 is suppressed, and the altitude dial 10 is not eccentric. By interposing the bearing balls 11, it is possible to prevent an increase in frictional force due to the load of the winding spring 14 applied to the end surface 2a of the horizontal shaft 2, and to ensure smooth rotation of the horizontal shaft 2. ..

According to the horizontal shaft structure of this embodiment, since the radial play and the thrust play of the horizontal shaft 2 can be greatly suppressed, the horizontal shaft 2 is stable and the error in reading the scale in the optical reading device is large. Is eliminated or the encoder signal in the electronic reading device is stabilized, and as a result, the altitude angle measurement accuracy of the surveying instrument is improved.

FIG. 2 is a broken sectional view showing a horizontal shaft structure according to another embodiment of the present invention. The embodiment described above concerns a support structure for one horizontal axis 2, whereas this embodiment relates to a support structure for both horizontal axes 2, 3. However, since the support structure of the one horizontal shaft 2 in this embodiment is the same as that of the above-mentioned embodiment, the description of the common parts will be omitted.

As shown in FIG. 2, the inner peripheral surface of the bearing 16 in the support column 5 is formed in a tapered shape, and a plurality of bearing balls 21 are arranged on the tapered surface 16a. The thrust receiving surface of the flange portion 19 of the horizontal shaft 3 is supported.

According to the horizontal shaft structure of this embodiment, the horizontal shafts 2 and 3 are more stable, and the orthogonality between the horizontal shafts 2 and 3 and the vertical shaft (corresponding to the vertical position 111 in FIG. 5) varies. The accuracy of the surveying instrument is further improved.

In the adjustment of the surveying instrument, the horizontal axes 2, 3
It is necessary to obtain the orthogonality between the vertical axis and the vertical axis, but in many cases, the bearings 6 and 16 of the horizontal axes 2 and 3 are moved up and down for adjustment. The present invention also takes that point into consideration. Since the taper and the bearing structure have a centripetal action, they have a relative degree of freedom with respect to the inclination of the shaft.
It is possible to move 6 a little.

In the embodiment shown in FIG. 2, the tapered surface 16a is formed on the bearing 16, but as a modification, the tapered surface is formed on the flange portion 18 of the horizontal shaft 3. Also, the same effect as the embodiment of FIG. 2 can be obtained.

[0024]

As described above, according to the horizontal axis structure of the surveying instrument of the present invention, the play in the thrust direction and the play in the radial direction of the horizontal axis are largely suppressed, the horizontal axis is stabilized, and the reading in the scale reading device is performed. Error is eliminated, and as a result, the accuracy of measuring the altitude angle of the surveying instrument is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a horizontal axis structure of a surveying instrument according to an embodiment of the present invention.

FIG. 2 is a broken sectional view showing a horizontal axis structure of a surveying instrument according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional horizontal axis structure.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view of a surveying instrument equipped with the horizontal axis structure of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Telescope 2, 3 ... Horizontal axis 2a ... End surface of horizontal axis 4, 5 ... Strut 6 ... Bearing 6a ... Tapered surface of bearing 8 ... Collar part 10 ... Advanced scale plate 11 ... Bearing ball 12 ... Pressing mechanism 13 ... Spring holder 14 ... Winding spring 15 ... Ball support 15a ... Dimple of ball support 16 ... Steel ball

Claims (2)

[Claims] 1. A horizontal axis structure of a surveying instrument in which a bearing for rotatably supporting a horizontal axis of a telescope is fixed in a column, and an altitude graduation plate is fixed to the horizontal axis. A bearing surface is provided, and the inner peripheral surface of the bearing that supports the horizontal shaft is tapered, and a plurality of bearing balls are arranged between the tapered surface and the thrust bearing surface, and the horizontal axis always has a predetermined axial direction. A horizontal axis structure of a surveying instrument, wherein a pressing mechanism that presses the thrust receiving surface toward the tapered surface by applying the load is attached in the support column. 2. As the pressing mechanism, a holder facing the end face of the horizontal shaft is fixed in the column, an elastic body is housed in the holder, and a sphere support is slidably housed. A recess is provided at the tip of the sphere support, a steel ball is arranged between the recess and the end face of the horizontal shaft, and a mechanism for applying a load of the elastic body to the end face of the horizontal shaft through the steel ball is provided. The horizontal axis structure of the surveying instrument according to claim 1, which is adopted.