JPH028242Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a focusing mechanism in a telescope for a surveying instrument.

As shown in FIG. 1, the focusing mechanism of the telescope of a known survey instrument includes a rack 3 on a focusing lens frame 1, and a pinion bearing metal 4 attached to the telescope barrel 2 through the side. A pinion 7 that passes through a pinion shaft 6 fixed to a guide portion 5' formed protruding from the center of the inner surface of the hot knob 5 and is attached to the tip of the pinion shaft 6 is engaged with the rack 3, 1: 1, the stop pin 8 is made to protrude from the back of the pinion bearing metal 4 toward the inner surface of the focusing knob 5, and the stop pin 9 is made to protrude from the inner surface of the focusing knob 5 toward the bearing metal 4. Stop plates 10, 10 fitted and fixed to guide portion 5' are held between stop pins 8, 9 to stop the operation of rack 3 and pinion 7 in the front and rear directions. Then focus knob 5
When you adjust the rotation back and forth, the pinion shaft 6 also moves together.
Therefore, the focusing lens frame 1 is adjusted by moving in the front-rear direction of the telescope, that is, in the direction of the arrow Y--Y' in FIG. 1, by the rack 3 meshing with the pinion 7. X-
X' is the center line of the pinion shaft.

In the known focusing mechanism as described above, the rack and pinion operate in a ratio of 1:1, and the focusing lens frame 1 and therefore the focusing lens move in a ratio of 1:1. Since the state of focus is determined by human vision, the visual tracking does not match the tracking of the focus, making it difficult to focus.

The purpose of this invention is to provide a coarse and fine movement device for focusing in a surveying instrument that can quickly and accurately focus the focusing lens of the focusing mechanism by providing a two-stage coarse and fine movement device in the focusing mechanism. That is.

The present invention will be described below with reference to the embodiments shown in the drawings.

A rack 12 is provided on a focusing lens frame 11. An opening 14 is provided at a side position of the telescope barrel 13 corresponding to the rack 12, and a coarse motion bearing sleeve 15 is fitted and fixed to a bearing portion 13' provided in the opening. The coarse movement shaft cylinder 16 is rotatably inserted. A fine movement mechanism is configured within the coarse movement shaft cylinder 16.
That is, the pinion shaft cylinder 17 is rotatably fitted into the coarse movement shaft cylinder 16, and the pinion 18 provided at the tip of the pinion shaft cylinder 17 is meshed with the rack 12.
A focusing knob 30 externally fitted to the coarse motion bearing sleeve 15
The focusing knob shaft 19 protruding from the center of the inner surface of the pinion shaft is rotatably inserted into the pinion shaft cylinder 17, and the ball 2
0 and the pinion shaft cylinder 1 by the spring 21.
It is resiliently stopped by the front wall 17' of the hole 7. Focusing knob shaft 19
has a mechanism that cannot be removed from the pinion shaft cylinder 17. That is, the focusing knob shaft 19 has a circumferential surface with a groove 19' having a taper α that becomes thicker toward the tip of the shaft, that is, toward the ball 20 side.
By providing a ball fitting hole 22 and fitting a ball 23 therein, the ball 23 is brought into contact with the groove 19' of the focusing knob shaft 19 and the inner wall of the coarse movement shaft cylinder 16. Configure a fine movement mechanism as non-removable. The coarse movement mechanism has a pin 2 on the rear end surface of the coarse movement shaft cylinder 16.
4, and pins 25 and 26 are projected and fixed on the inner surface of the focusing knob 30 at positions where the pin 24 and the side surfaces thereof face each other. The side surface of the pin 24 is made press movable to constitute an interlocking mechanism that transmits the rotation of the focusing knob to the coarse movement shaft cylinder 16 at a ratio of 1:1. A stop plate 27 is fixed to the pinion shaft cylinder 17 between the pinion 18 and the coarse movement shaft cylinder 16, and a stop pin 29 is attached to the tip of the coarse movement bearing cylinder 15 so that the stop plate 27 can be clamped. Shaft tube 1
A stop pin 28 is provided on the distal end surface of the lens 6 to form a stopper mechanism that restricts the rotation of the focusing knob within a certain range. Further, a leaf spring (not shown) is provided above the pinion 18 to sandwich the pinion 18 together with the rack 12.

When the focusing knob 30 is rotated, the ball 23 rotates and at the same time revolves around the groove 19' of the focusing knob 19, causing the pinion shaft cylinder 17 to rotate, and thus the pinion 18 to rotate. At this time, one rotation of the focusing knob 30 is decelerated, and the pinion shaft 17, that is, the pinion 18, is also rotated at a deceleration rate.

That is, as shown in FIGS. 4 and 5, focus knob 3
0 rotation is Ni, the revolution angle of the ball 23 is Nω, the ball
The diameter of the ball 23 is Da, the orbital diameter of the ball 23 is dp,
If the taper angle provided at the tip of the focusing knob shaft 19 is α, the reduction ratio is expressed as Nω/Ni=0.5 (1-Da/dpcosα), and α→0, cosα≒1, 2Da=dp. Then, Nω/Ni=0.25, Nω:Ni=1:4, and the speed is reduced.

Fine rotation is performed as described above, but when the focusing knob 30 is further rotated, coarse rotation is performed.

When the focusing knob 30 is further rotated, the side surface of one of the pins 25 and 26 protruding from the inner surface of the focusing knob 30 will become the side surface of the pin 24 provided on the coarse movement shaft cylinder 16. Press the coarse movement shaft cylinder 16.
is interlocked with the focusing knob 30 and rotates with the pinion shaft cylinder 17 at a ratio of 1:1. Therefore, the pinion 18 also rotates at a ratio of 1:1 with the coarse movement shaft cylinder 16 and the focusing knob 30. The pinion 18 is held between the rack 12 and a leaf spring (not shown) and rotates without rattling.
Therefore, the focusing lens frame 11 moves back and forth without wobbling. A stop plate 27 fixed to the pinion shaft cylinder 17 is sandwiched between a stop pin 28 projecting from the coarse movement shaft cylinder 16 and a stop pin 29 projecting from the coarse movement bearing cylinder 15, and the stop plate 27 is engaged by the above-mentioned stopper mechanism. The amount of movement of the focusing lens frame 11 is limited. Therefore, the amount of rotation of the focusing knob is also restricted.

As described above, this invention allows the focusing lens to focus in two stages, fine and coarse, to match visual tracking and focus tracking, making focusing accurate, quick and easy. Not only that, but since the ball 23 is in contact with the focusing knob shaft 19, the pinion shaft cylinder 17, and the coarse movement shaft cylinder 16, it is possible to create a mechanism without play, and it is possible to focus by going back and forth. This has the advantage of making it easier to focus.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a conventional focusing mechanism, FIG. 2 is a vertical cross-sectional view of the focusing mechanism of the present invention, FIG. 3 is a cross-sectional view illustrating the stopped state of the focusing mechanism of the present invention, and FIG.
The figure is a diagram showing the relationship between the focusing knob shaft and the ball, and FIG. 5 is a diagram showing the repressive state of the focusing knob shaft, the ball, and the focusing knob shaft. 11...Focusing lens frame, 12...Rack, 13
...Telescope barrel, 15...Coarse motion bearing tube, 16...
Coarse movement shaft cylinder, 17...Pinion shaft cylinder, 18...Pinion, 19...Focusing knob shaft, 19'...Taper groove, 20...Ball, 21...Spring, 2
2...Ball fitting hole, 23...Ball, 24...
Pin, 25, 26... Pin, 27... Stop plate, 28, 29... Stop pin, 30... Focusing knob.

Claims (1)

[Scope of utility model registration request] A pinion shaft tube of a pinion that meshes with a rack provided in the focusing lens frame, and a coarse movement shaft tube rotatably circumscribed using the pinion shaft tube as a guide shaft are provided on the lens barrel side of the telescope. The focusing knob shaft provided on the inside of the focusing knob is inserted into the inner part, and the ball fitted into the ball fitting hole of the pinion shaft cylinder is inserted into the tapered groove of the focusing knob shaft. A fine adjustment mechanism configured to touch and contact the inner wall of the coarse adjustment barrel, an interlocking mechanism that transmits the rotation of the focusing knob to the coarse adjustment barrel at a ratio of 1:1 after the fine adjustment, and rotation of the focusing knob. 1. A coarse and fine focusing device for a surveying instrument, comprising a coarse movement mechanism equipped with a stopper mechanism for restricting the distance to a certain range.