JP2537270Y2 - Rotary shaft coarse / fine movement device of surveying instrument - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coarse and fine rotary shaft moving device for turning a horizontal rotary shaft or the like of a collimating telescope of a surveying instrument by a very small amount.

[0002]

2. Description of the Related Art Generally, in a surveying instrument such as a theodolite, in order to roughly rotate a horizontal rotating shaft of a telescope by a very small amount, a tightening frame is fixed to the rotating shaft, and the rotating shaft and the tightening frame are rotated around the axis by a coarse / fine movement device. In this case, the rotation is performed by using a rotating means. FIG. 3 shows an example of a conventional rotary shaft coarse / fine movement device. The coarse / fine movement device is coaxially integrated with a tightening device. That is, as shown in FIG. 3, the tightening frame 2 is loosely fitted to the horizontal rotating shaft 1, and the cam 2 b for tightening the tightening frame 2 via the joint portion 5 is rotated integrally with the operating shaft 4. Are located in When the tightening knob 4a is turned, the cam 2b rotates integrally with the operating shaft 4, and the push rod 2c presses the tightening piece 2d against the rotating shaft 1, and the tightening frame 2 is fixed to the rotating shaft 1, and the tightening frame is fixed. 2 and the rotating shaft 1 can be rotated integrally.

A fine moving shaft 9 is further screwed into a coarse moving cylinder 8 which is screwed into an outer cylinder 7 fixed to the body casing 3, and the fine moving shaft 9 is formed into a cylindrical shape. The operating shaft 4 inserted therein is urged toward the outside of the casing (leftward in FIG. 3) by the urging member 6, and the protrusion 4 b provided on the operating shaft 4 causes the thrust bearing 4 c
And is supported on the fine movement shaft 9 through the shaft. And the fine movement axis 9
When the coarse / fine movement knob 9a fixed to the cylinder is turned, the contact pin 9b inside the coarse / fine movement knob 9a is
b, the fine moving shaft 9 rotates with respect to the coarse moving cylinder 8, and the coarse moving cylinder 8 rotates with respect to the outer cylinder 7 when the contact pin 9b is in contact with the contact piece 8b. It is supposed to. At this time, the screwing lead of the screwing portion 8c between the outer cylinder 7 and the coarse moving cylinder 8 is larger than the screwing lead of the screwing portion 8a between the coarse moving cylinder 8 and the fine moving shaft 9. The fine movement shaft 9 moves a small amount for a certain amount of rotation of the fine movement knob 9a.
Performs coarse movement. Since the operating shaft 4 advances and retreats in the axial direction with the two reciprocating cylinders 8 and 9 integrally, the rotating shaft rotates slightly. That is, the rotating shaft 1 is linked so as to rotate in proportion to the amount of movement of the operating shaft 4.

The joint 5 has a slit 5a.
By the engagement between the rod 5c and the pin 5b, the rotational force is increased.
Due to the engagement with d, the axial pressing force is smoothly transmitted regardless of the position of the tightening frame arm 2a with respect to the operating shaft 4.

[0005]

In the collimating operation of the telescope, there is a demand for fine rotation of the rotary shaft 1. To meet this demand, the coarse moving cylinder 8 and the fine moving shaft 9 are required.
It is conceivable to reduce the screw lead. However, in theory, if the lead is made smaller, a smaller amount of advance and retreat should be possible, but in reality, reducing the lead of the threaded portion is limited in terms of processing accuracy and material durability. In this case, it was difficult to rotate the rotating shaft by a very small amount.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a rotary shaft coarse / fine movement device of a surveying instrument capable of rotating a rotary shaft by an extremely small amount.

[0007]

In order to achieve the above object, in a coarse and fine rotary shaft moving device of a surveying instrument according to the present invention, a cylinder formed in a coarse moving cylinder fixed and held on a body casing during a fine moving operation. A first piston on the actuation side, which is a fine movement shaft screwed into the coarse moving cylinder and having a tip portion accommodated in the cylinder, and a second piston on the actuation side accommodated in a front position of the first piston in the cylinder. A two-piston, a power transmission member interposed between the first piston and the second piston, an urging member for urging the second piston toward the first piston,
A rotating shaft that is linked to the second piston and that rotates in proportion to the amount of movement of the second piston. The power transmission member is formed of a deformable member, and the power transmission member is in contact with the power transmission member. The cross-sectional area of the end of the two pistons is set to be larger than the cross-sectional area of the end of the first piston abutting on the power transmission member so that the amount of advance and retreat of the first piston in the cylinder is reduced and transmitted to the second piston. Configured.

[0008]

[0009]

The first piston, which is a fine moving shaft screwed to the coarse moving cylinder having the cylinder formed therein, is rotated to rotate the first piston in the cylinder at a screw lead speed of a threaded portion between the coarse moving cylinder and the fine moving shaft. Go back and forth. The urging member urges the second piston toward the inside of the cylinder, and the second piston, which is constantly pressed against the first piston via the power transmission member, changes its overall shape by the pressing force of the first piston. Power is transmitted via the power transmission member, and moves in and out of the cylinder in conjunction with the movement of the first piston. The rotating shaft linked to rotate in proportion to the amount of movement of the second piston rotates in proportion to the amount of movement of the second piston.

The ratio of the amount of advance and retreat of the two pistons with respect to the cylinder is inversely proportional to the ratio of the cross-sectional area of the ends of the two pistons abutting on the power transmission member, and the cross-sectional area is larger in the first piston than in the second piston. Is smaller in the second piston than in the first piston which is the fine movement axis. Therefore, the rotating shaft rotates (finely moves) by an amount smaller than the amount corresponding to the amount of movement of the fine moving shaft.

[0011]

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show an embodiment in which the present invention is applied to a coarse / fine movement device for coarsely and slightly rotating a horizontal axis of a theodolite telescope, and a rotary shaft coarse / fine movement device coaxially integrated with a tightening device. Is shown.

In these figures, this rotary shaft coarse / fine movement device is the same as the above-mentioned conventional coarse / fine movement device (see FIG. 3) except for a part of the structure shown enlarged in FIG. Will be described in detail, the same reference numerals will be used for the other elements, and redundant description will be omitted. That is, the end 8e of the coarse moving cylinder 8 on the machine casing side and the operating shaft 4 facing the end 8e.
Of the fine movement shaft 9 and a first piston 30 formed at the distal end of the fine movement shaft 9, which is externally fitted to the shaft 4 in front of the first piston 30. A ring-shaped second piston 40 is provided. Both pistons 30 and 4 in cylinder 20
A power transmission member 50 is interposed between zero. The power transmission member 50 is constituted by a member whose volume does not change with temperature but can be deformed to a shape following an external force applied state while maintaining a constant volume when an external force acts. And the power transmission member 50 in the present embodiment
Has a structure in which an incompressible fluid such as oil having a small coefficient of thermal expansion is sealed in a hollow donut formed of a thin rubber film or the like. The gap between the cylinder 20 and the first piston end 30a and the second piston end 40a is
It is narrow enough so that 0 does not enter. In addition, a space between the ring-shaped cross-section room formed inside the coarse moving cylinder casing side end 8e and accommodating the power transmission member 50 and the ring-shaped cross-section room where the first piston 30 is disposed. Is formed with a step 20a, and the cross-sectional area “A ₁ ” of the first piston end 30a is set smaller than the cross-sectional area “A ₂ ” of the second piston end 40a.

That is, the first piston 30 is screwed to the outer cylinder 7 fixed to the body casing 3 and the second piston 4
0 is urged toward the inside of the cylinder 20 by the urging member 6, so that when the fine movement shaft 9 rotates in the coarse movement cylinder 8 and advances and retreats with the screw lead of the screw portion 8a, the shape change is easy. The power transmission member 50 changes into a shape corresponding to the position of the first piston end 30a. For example, when the piston end 30a moves forward and presses the power transmission member 50, the power transmission member 5
0 pressed area A ₁ corresponding parts in the piston end 30a presses the area A ₂ corresponding portions of the opposite side, the second piston 40
Moves forward. As described above, with the shape change of the power transmission member 50, the second piston 40 advances and retreats, and the second piston 40
The horizontal shaft 1 rotates in proportion to the amount of advance / retreat. At this time, the advance / retreat amount of the first piston 30 is set to “L ₁ ”, and the second piston 40
Assuming that the amount of advance / retreat is “L ₂ ”, “L ₂ = L ₁ (A ₁ / A ₂ )”
And “A ₁ <A ₂ ” (described above) indicates “(A ₁ /
A ₂ ) <1 ”, and as a result,“ L ₂ <L ₁ ”. That is, in the present embodiment, the rotating shaft 1 is
Since it rotates in proportion to the advance / retreat amount “L ₂ ” of 0, the fine moving cylinder 8
The rotation of the rotation shaft 1 is even smaller than that of the conventional example shown in FIG. 3 which rotates in proportion to the advance / retreat amount “L ₁ ”.

The shape of the contact portion of the end of the first piston 30 and the end of the second piston 40 with the power transmission member 50 may be any shape within a range where the condition of "A ₁ <A ₂ " is satisfied. Is fine. Further, as another embodiment, the power transmission member 50 may be formed of an inelastic body whose volume does not change not only with temperature but also with pressure, for example, a set of many small steel balls or ceramic balls. .
In the above-described embodiment, the power transmission member 50 has been described as an incompressible member.
For example, fine movement can be achieved by using a rubber material.

[0016]

As is clear from the above description, according to the present invention, the amount of reciprocation with respect to the cylinder is smaller in the second piston than in the first piston, and the ratio of the amount of reciprocation of both pistons to the cylinder is equal to that of both pistons. Since it is inversely proportional to the ratio of the cross-sectional area of the end portion abutting on the power transmission member, by arbitrarily setting the ratio of the cross-sectional area of both piston end portions,
The ratio of the amount of advance and retreat of the two pistons with respect to the cylinder can be freely determined. Therefore, when the ratio of the cross-sectional area of both piston end portions is set to be large, the ratio of the amount of advance and retreat of the two pistons to the cylinder also increases, and the amount of advance and retreat of the second piston to the cylinder is larger than the amount of advance and retreat to the cylinder of the first piston. Is extremely small, the rotation of the rotating shaft linked to the second piston can be made very small.

Also, instead of reducing the pitch of the screw, by increasing the cross-sectional area ratio of the abutting portion of the first and second pistons, it is possible to advance and retreat very finely. As compared with the case where the size is reduced to the minimum, the requirements for the material and the processing accuracy are not strict and economical, and the durability can be increased. Also, thermal expansion of the power transmission member
If the coefficient is set as small as possible, the rotation axis will not rotate due to temperature changes , so that the telescope will not be able to collimate even under severe temperature fluctuations such as when used outdoors for a long time. Nor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary fine-motion device of a surveying instrument according to an embodiment of the present invention;

FIG. 2 is an enlarged view of a main part of a rotary shaft coarse / fine movement device of a surveying instrument according to an embodiment of the present invention;

FIG. 3 is a longitudinal sectional view of a conventional rotary shaft coarse / fine movement device of a surveying instrument.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 rotating shaft 3 casing 6 biasing member 8 coarse moving cylinder 8a screwing portion of coarse moving cylinder and fine moving shaft 9 fine moving shaft 10 main part of rotary shaft coarse / fine moving device of surveying instrument 20 cylinder 30 first piston 30a of first piston End that contacts the power transmission member 40 Second piston 40a End of the second piston that contacts the power transmission member 50 Power transmission member A ₁ Cross-sectional area of first piston end A ₂ Cross-section of second piston end area

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylinder formed in a coarse moving cylinder fixedly held to a machine casing during a fine movement operation, and a cylinder formed at a distal end portion of a fine moving shaft screwed into the coarse moving cylinder and housed in the cylinder. An actuation-side first piston, an actuation-side second piston housed in a cylinder in front of the first piston, and a power transmission member interposed between the first piston and the second piston; An urging member for urging the second piston toward the first piston, and a rotating shaft linked to the second piston and rotating in proportion to the amount of movement of the second piston; Is constituted by a deformable member, and the cross-sectional area of the second piston end contacting the power transmission member is made larger than the cross-sectional area of the first piston end contacting the power transmission member. 1st fixie A coarse and fine movement device for a rotary shaft of a surveying instrument, wherein the amount of advance and retreat of the rotation shaft is reduced and transmitted to a second piston.