JP2003097947A - Surveying instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surveying instrument capable of constantly maintaining optimum meshing state between a worm and a worm gear without special adjustment in a surveying instrument having a worm oscillating mechanism for rotating a telescope or the main body of the surveying instrument. SOLUTION: The surveying instrument comprises a worm gear (43) for rotating the telescope (34) or the main body of the surveying instrument (20), a worm shaft (90) around which a worm (92) meshing with the worm gear (43) is formed, a bearing body (70) provided on the both ends thereof with bearings (94) supporting the worm shaft (90), a bearing housing (74) supporting the bearing body (70), a compression coil spring (84) energizing the bearing body (70) to the worm gear side, and rubber springs (72a, 72b), which are disposed between the bearing body (70) and the bearing housing (74), resisting the biasing force by the compression coil spring (84).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveying instrument such as a total station, a theodolite, an optical distance meter, a level, etc. The present invention relates to a surveying instrument that controls rotation around an electric motor.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a conventional example of a surveying instrument. 4 is a vertical cross-sectional view of the surveying instrument, FIG. 5 is a rear view of the surveying instrument, and also shows a cross-section along the line II-II in FIG.
As shown in these figures, the surveying instrument main body is rotatably mounted on the leveling table 10. That is, the leveling table 10
A shaft cylinder 12 extending upward is vertically provided on the shaft cylinder 12.
A vertical shaft 22 vertically hung from the lower surface of the surveying instrument main body is rotatably supported via a bearing 14. Shaft cylinder 1
2 and the vertical axis 22 have a disk scale 24 at the upper end thereof.
And a mask graduation 25 are opposed to each other with a minute gap therebetween, and a light emitting element and a light receiving element (not shown) are opposed to each other with the disk graduation 24 and the mask graduation 25 interposed therebetween. The two scales 24 and 25, the light emitting element, and the light receiving element constitute an angle detection unit of a rotary encoder that detects the horizontal rotation angle of the surveying instrument body 20 from the amount of rotation of the disk scale 24 with respect to the mask scale 25.

Further, as shown in FIG. 5, the surveying instrument main body 2
Two columnar portions 30 facing each other are formed at 0, and a horizontal shaft 32 rotatable around an axis is spanned between the columnar portions 30, and a telescope 34 is perpendicular to the horizontal shaft 32.
Is fixed. In one of the columnar portions 30, a disc scale (not shown) is fixed to one end of the horizontal shaft 32, and is arranged so as to face the mask scale fixed to the columnar portion with a predetermined gap therebetween. The light emitting element and the light receiving element are arranged so as to face each other. These two scales, the light emitting element, and the light receiving element constitute an angle detection unit of a rotary encoder that measures the altitude angle of the telescope 34 from the rotation of the mask scale with respect to the disk scale.

Inside the other columnar portion 30, there is arranged a worm swing mechanism 38 including a worm gear 43 fixed to the horizontal shaft 32 and a worm shaft 40 having a worm 42 meshing with the worm gear 43. . One end of the worm shaft 40 has a columnar portion 30 and a universal bearing 5
While being supported via 6, the other end of the worm shaft 40 is guided by a slide groove 45 formed in the removable metal 44 so as to extend in the vertical direction.
The worm shaft 40 has a structure capable of swinging motion around the universal bearing 56.

The removable metal 44 has a universal bearing 56.
An arc surface 44a centered on is formed. An operation knob 48 (48A) is fixed to the other end of the worm shaft 40, and a slide having a curved surface that is slidable along the arc surface 44a between the operation knob 48 (48A) and the arc surface 44a. The metal 46 is assembled. When the worm shaft 40 rotates about its axis, a space between the slide metal 46 and the operation knob 48A serves as a rotation surface.

The worm shaft 40 has a slide groove 45.
The metal bush 49 disposed inside penetrates the metal bush 49, and the pin 52 biased by the compression coil spring 50 pushes the metal bush 49 upward, whereby the worm 42 is biased in the direction in which it meshes with the worm gear 43. Has been done.

An electric motor 66 is fixed in the columnar portion 30 by a bracket 65, and a spur gear 64 fixed to the output shaft of the electric motor and a spur gear 62 fixed to the other end of the worm shaft 40. Meshes with and both gears 6
The gear transmission mechanism 60 is configured by 2, 64.
An operation knob 48 (48B) for rotating the worm shaft 40 is pivotally attached to the other end of the worm shaft 40.

Thus, the worm 42 and the worm gear 4
Since a drive mechanism using 3 and 3 can be used, a large reduction ratio and drive torque can be obtained, and even if the forward rotation and the reverse rotation are frequently repeated between minute angles, the rotation axis can be quickly and accurately rotated. Can be controlled to rotate.

Next, a procedure for rotating the telescope 34 will be described. When it is desired to rotate the telescope 34 using the electric motor 66 or the operation knob 48, as shown in FIG. 3, the worm 42 of the worm shaft 40 and the worm gear 4 are rotated.
The electric motor 66 or the operation knob 48 may be rotated in a state in which 3 and 3 are engaged with each other. On the other hand, when directing the telescope 34 directly to the target when directing it toward the target, one of the operation knobs 48A is pushed down in the downward direction A to move the worm shaft 40 to the universal bearing 56.
The worm shaft 43 is swung downwards to disengage the worm gear 43 and the worm 42 from each other, and the worm shaft 40 is clamped by a clamp means (not shown). In this state, the telescope 34 can freely rotate around the horizontal axis 32.

After the telescope 34 is freely rotated, when the telescope 34 is slightly rotated by the electric motor 66 or the operation knob 48, one of the operation knobs 48A is pushed upward, and the worm shaft 40 is not shown. The worm shaft 40 is easily disengaged from the clamp, and the worm shaft 40 is rotated about the universal bearing 56 by the urging force of the compression coil spring 50 to return to the original state where the worm 42 and the worm gear 43 mesh with each other. Then, while observing the telescope 34, the operation knob 48 or the electric motor 66 is slightly rotated, and the target can be collimated accurately.

Although the rotation mechanism of the telescope 34 about the horizontal axis has been described above, the rotation mechanism of the surveying instrument main body about the vertical axis also has a worm shaft 40 when the worm 42 disengages from the worm gear 43. Since they have the same structure except that they are oscillated in the horizontal direction, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0012]

[Problems to be Solved by the Invention] By the way, the worm 4
Between the 2 and the worm gear 43, there is a gap called backlash in each meshed tooth in order to avoid a defect due to a machining error or due to wear caused by use. If there is such backlash, warm 42
When the worm gear is rotated in the reverse direction, a time delay occurs until the worm gear 43 rotates in the reverse direction. Due to this time delay, the positioning accuracy of the telescope 34 and the surveying instrument main body 20 deteriorates, and the time required for the positioning also increases. .

In the above-mentioned conventional example, the urging force of the compression coil spring 50 presses the worm 42 toward the worm gear 43 to minimize the backlash and to keep the worm 42 and the worm gear 43 constant. It keeps the meshing state of. This allows
As described above, the time delay at the time of reverse rotation is reduced, and the telescope 3
4 and the positioning accuracy of the surveying instrument main body 20 are deteriorated, and the time required for positioning is lengthened.

However, the compression coil spring 50
The urging force of requires a certain amount or more, but if this urging force is too strong, the torque required to rotate the worm gear 43 increases, so that the power consumption increases,
It becomes difficult to control the rotation of the telescope 34, etc.
If the urging force is too weak, the worm shaft 40 is likely to vibrate, so that there is a problem that it is difficult to control the rotation of the telescope 34 and the like.

In order to solve such a problem, the biasing force of the compression coil spring 50 may be optimally adjusted at the time of manufacturing, but even if the biasing force of the compression coil spring 50 is optimally adjusted at the time of manufacturing. Even if it is possible, the urging force of the compression coil spring 50 will not be optimal depending on the environment when the surveying instrument is used, and the telescope 3
It may be difficult to control the rotation of the fourth gear and the like. For example, if the temperature at the time of use changes from that at the time of manufacture, the entire mechanical portion expands or contracts due to the temperature change, so the biasing force of the compression coil spring 50 may become too large or too small, and the telescope 34, etc. It may be difficult to control the rotation. Further, when the biasing force of the compression coil spring 50 gradually weakens due to aging, the optimum biasing force cannot be maintained, the worm shaft 40 easily vibrates, and it may be difficult to control the rotation of the telescope 34 or the like. . As described above, it is difficult to always maintain the meshed state of the worm 42 and the worm gear 43 by the optimum biasing force of the compression coil spring 50.

The present invention has been made in view of the above problems, and in a surveying instrument equipped with a worm swing mechanism composed of a worm gear and a worm for rotating a telescope or a surveying instrument main body, without any particular adjustment, (EN) Provided is a surveying instrument capable of maintaining a proper worm and worm gear meshing state.

[0017]

In order to solve the above problems, a surveying instrument of the invention according to claim 1 is provided with a worm gear for rotating a telescope or a surveying instrument main body, and a worm that meshes with the worm gear. A worm shaft, and a bearing forming body having bearings for supporting the worm shaft provided at both ends,
A bearing housing that supports the bearing forming body, a first elastic body that biases the bearing forming body toward the worm gear, and a first elastic body between the bearing forming body and the bearing housing. It is characterized in that a second elastic body that resists the urging force is interposed.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the second elastic body is a rubber ring disposed at both ends of the bearing forming body.

In the invention according to claim 3, in the invention according to claim 2, a rubber ring is arranged also between a flange provided at one end of the bearing forming body and one end surface of the bearing housing. Characterize.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a surveying instrument of this embodiment, and FIG. 2 is an enlarged sectional view of a worm swing mechanism portion in FIG.

In the surveying instrument of this embodiment, the surveying instrument main body 20 is horizontally rotatably mounted on a leveling table, and the surveying instrument main body 20 is formed with columnar portions 30 facing each other. A horizontal shaft 32 is laid between the columnar parts 30 so as to be rotatable about the axis, and a telescope 34 is fixed to the horizontal shaft 32. Since this configuration is the same as the conventional example shown in FIG. 4, description thereof will be omitted. In the present embodiment, a handle 98 is stretched between the two columnar portions 30 so as to be convenient to carry.

A worm shaft 90 on which a worm 92 is formed is arranged in one columnar portion 30 of the surveying instrument main body 20 along a direction orthogonal to the horizontal shaft 32, and the worm 92 is fixed to the horizontal shaft 32. It meshes with the worm gear 43 that has been removed.

The worm shaft 90 has a cylindrical bearing forming body 70.
Is supported by bearings 94 provided at both ends of the bearing forming body 70. The bearing forming body 70 is notched on the side facing the worm gear 43, and the worm 92 is exposed from the bearing forming body 70. In order to dispose the worm 92, the surface of the bearing forming body 70 on the side opposite to the worm gear 43 and both side surfaces swell from the portion where the worm 92 is arranged to one end side.

The bearing forming body 70 is housed inside a cylindrical bearing housing 74 fixed to the surveying instrument main body 20 and is swingable about one end side as a swing center P.
FIG. 3 shows a horizontal sectional view near the swing center P. A circular through hole 99 is provided on one end side of the bearing housing 74, a screw 95 having a circular head is inserted into the circular through hole 99, and the tip of the screw is screwed into one end of the bearing forming body 70. Thereby, the bearing forming body 70 can swing with the screw 95 as the swing center P.

The bearing housing 74 is provided at both ends with ends 76 having holes 75 for supporting the bearing forming body 70. The inner peripheral surface of the hole 75 has the rubber rings 72a, 72b.
Both ends of the bearing forming body 70 are supported by interposing. Specifically, the rubber rings 72a and 72b are used as the bearing forming body 7.
By engaging with the groove 71 provided on the outer periphery of both ends of 0 and the groove 77 provided on the inner peripheral surface of the hole 75, the bearing forming body 7
It is prevented from slipping out of the bearing housing 74 of 0. The bearing housing 74 is also notched on the side facing the worm gear 43, and the worm 92 is also exposed from the bearing housing 74 and meshes with the worm gear 43. Further, the bearing forming body 70 is provided with a flange 78 on one end side, and the rubber ring 73 is also interposed between the one end face 80 of the bearing housing 74 and the flange 78. The worm shaft 70 is fixed by one end of the worm 92 and the bearing 94, and the other end of the worm 92 and the bearing 100 of the bearing 94 to prevent the worm shaft 70 from rattling in the thrust direction.

The bearing housing 74 includes an electric motor 66.
Is fixed, and the spur gear 6 is attached to the output shaft of this electric motor.
4 is fixed, and the spur gear 62 is attached to one end of the worm shaft 90.
Are fixed, and both spur gears 62 and 64 mesh with each other to form a spur gear transmission mechanism 60. In this embodiment, the gear mechanism is the spur gear transmission mechanism 60 including the spur gears 62 and 64, but another appropriate transmission mechanism such as a bevel gear mechanism or a worm gear mechanism may be used.

The surface of the bearing housing 74 on the side opposite to the worm gear 43 is partially bulged, and a hole 82 is provided in a portion of the bulging portion near the worm 92.
A compression coil spring 84 is installed in this hole 82. This compression coil spring 84 (first elastic body)
Is interposed between the bearing forming body 70 and the bearing housing 74, and the bearing forming body 70 is attached to the rubber rings 72 a, 72.
b, 73 (second elastic body) is urged toward the worm gear 43 side against the resistance force from the worm 92 and the worm gear 43.
And are trying to maintain an optimal mesh.

Since this embodiment is constructed as described above, it has the following operational effects. The compression coil spring 84 includes the rubber ring 72 via the bearing forming portion 70.
Although a part of a and 72b is compressed, since the rubber ring 72a is closer than the rubber ring 72b, the rubber ring 72a is mainly used.
By compressing a part of the rubber ring 73, the bearing forming body 70 is rotated with one end side thereof as the swing center P, and the bearing forming body 70 is pressed toward the worm gear 43 side.

Therefore, the operating temperature range of the device of the present invention is from -20 ° C to 70 ° C. However, even when the biasing force of the compression coil spring 84 becomes too large due to a temperature change or the like, the rubber ring is mainly used. Since 72a, 72b and the rubber ring 73 resist the biasing force of the compression coil spring 84 and reduce the biasing force of the compression coil spring 84,
The worm 42 and the worm gear 43 do not mesh with each other more than necessary, and an appropriate meshed state can be maintained. Further, even if the urging force of the compression coil spring 84 becomes weak due to aging or contraction of the compression coil spring 84, at that time, the compression coil spring 8 mainly
Since the resistance of the rubber rings 72a, 72b, 73 to the urging force of No. 4 also decreases, the worm 42 and the worm gear 43
And can maintain an appropriate meshing state.

Further, even if vibration is generated in the bearing forming body 70 that supports the worm shaft 90, the rubber rings 72a, 72b, 73, which are elastic bodies, efficiently damp the vibration of the bearing forming body 70. Further, as in the conventional example, the worm shaft 40
In the case where only the oscillating part is made oscillating, vibration due to pulse-like disturbance such as impact is likely to occur because the mass of the oscillating part is small, but in the present embodiment, the worm shaft 90 and the bearing forming body 70 are provided. Since the oscillating portion has a large mass and the natural frequency of the oscillating portion is lowered, vibration due to pulse-like disturbances can be reduced as compared with the conventional example in which only the worm shaft 40 can be oscillated. Is less likely to occur.

In the present embodiment, the rubber ring which is the second elastic body is arranged at three places, but it is not always necessary to arrange it at all three places, and it may be arranged at any one place or only two places. A sufficient effect can be obtained. In this case, the rubber ring 72a located farthest from the swing center P of the bearing forming body 70 is most effective.

As described above, in this embodiment, since the worm 92 and the worm gear 43 are always kept in the proper meshing state and the bearing forming body 70 is less likely to vibrate, the rotation control of the telescope 34 is controlled. Can always be done quickly and accurately.

In the above description, the horizontal axis 32 of the telescope 34 is
Although the rotating mechanism around the vertical axis has been described, the rotating mechanism around the vertical axis of the surveying instrument main body 20 has the same structure, and thus the description thereof is omitted.

By the way, the present invention is not limited to the above-described embodiment, and for example, as the first elastic body, instead of the compression coil spring 84, a tension coil spring or rubber for pressing the bearing forming body 70 toward the worm gear 43 side is used. As the second elastic body, rubber rings 72a, 72b are used.
Instead of, a compression coil spring, rubber or the like arranged along the circumferential direction may be used. However, from the viewpoint of ease of assembly of the worm swing mechanism, the rubber ring 7
2a and 72b are desirable. Furthermore, in order to make the bearing 70 swingable, one end side of the bearing housing 74 is provided with the structure shown in FIG.
You may use the universal bearing like the conventional example shown in FIG. In order to simplify the structure, three rubber rings 72 arranged between the bearing former 70 and the bearing housing 74.
It is also possible to omit one or two rubber rings from a, 72b, 73. In addition, the bearing housing 74 includes the columnar portion 3.
It may be configured integrally with 0.

[0035]

As is apparent from the above description, according to the invention of claim 1, the first elastic body presses the bearing forming body toward the worm gear side while compressing the second elastic body. Therefore, even when the urging force of the first elastic body becomes too large, the second elastic body resists the urging force of the first elastic body, and conversely, even when the urging force of the first elastic body becomes weak, Since the resistance of the second elastic body to the urging force of the elastic body also decreases, it is possible to always maintain an appropriate meshing state between the worm and the worm gear. Further, since the worm shaft and the bearing forming body are integrated to increase the mass of the oscillating portion, the vibration due to the pulsed disturbance is less likely to occur. In this way, the worm and the worm gear are always kept in an appropriate meshed state, and the worm shaft is less likely to vibrate, so that the rotation control of the telescope or the surveying instrument main body can always be performed quickly and accurately.

In the invention according to claim 2, since the rubber ring is used as the second elastic body, the vibration can be efficiently damped by the rubber ring which is the elastic body, so that the rotation control of the telescope or the surveying instrument main body is performed. It can be performed more quickly and accurately, and the worm swing mechanism can be easily assembled.

In the invention according to claim 3, a rubber ring is further arranged between the flange provided at one end of the bearing forming body and the one end surface of the bearing housing to more efficiently damp the vibration. The rotation control of the telescope or the surveying instrument body can be performed more quickly and accurately.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a surveying instrument according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a worm swing mechanism portion of the surveying instrument.

FIG. 3 is a horizontal sectional view taken along the line AA in FIG.

FIG. 4 is a vertical sectional view of a conventional surveying instrument.

FIG. 5 is a rear view of a conventional surveying instrument.

[Explanation of symbols]

20 Surveyor body 22 Vertical axis (rotating axis) 32 Horizontal axis (rotation axis) 34 Telescope, 40 worm shaft, 42 Warm, 43 Worm gear, 70 Bearing forming body 72a, 72b Rubber ring (second elastic body) 73 rubber ring (second elastic body) 74 Bearing housing 84 Compression coil spring (first elastic body)

Claims (3)

[Claims] 1. A worm gear for rotating a telescope or a surveying instrument main body, a worm shaft having a worm that meshes with the worm gear, a bearing forming body having bearings for supporting the worm shaft at both ends, and the bearing. A surveying instrument, comprising: a bearing housing that supports a forming body; and a first elastic body that urges the bearing forming body toward the worm gear, wherein the first elastic body is provided between the bearing forming body and the bearing housing. 1. A surveying instrument, wherein a second elastic body that resists the biasing force of the elastic body is interposed. 2. The surveying instrument according to claim 1, wherein the second elastic body is a rubber ring arranged at both ends of the bearing forming body. 3. The surveying instrument according to claim 2, wherein a rubber ring is also arranged between a flange provided at one end of the bearing forming body and one end surface of the bearing housing.