JP2535048Y2 - Camera zoom finder device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a camera zoom finder device, and more particularly, to a camera zoom finder device having a fixed lens group and a movable zoom lens group.

"Prior art and its problems" This kind of zoom finder device is used particularly for a variable focus lens shutter camera. This zoom finder device is installed in the camera body without being particularly separated from the photographing optical system and other driving devices, because the variable magnification lens group is moved in response to a change in the focal length caused by the photographing optical system.

For this reason, even when it is desired to disassemble only the zoom finder device for inspection or the like, it is necessary to disassemble other parts such as the camera body and the lens block of the photographing lens system, and the work is very troublesome. .

The purpose of the present invention is to solve such a problem of the conventional camera zoom finder device and to obtain a zoom finder device which can be easily assembled and disassembled without affecting other parts. With the goal.

Another object of the present invention is to simplify the timing adjustment when assembling the zoom finder device and to smoothly drive the drive gear train.

SUMMARY OF THE INVENTION The present invention is directed to a zoom finder device having a fixed lens group and a movable zoom lens group, wherein the fixed lens group, the movable zoom lens group, and the movable zoom lens group are disposed in front of or behind the optical axis direction. A biasing means for moving and biasing the lens, and a drive mechanism for driving the movable zoom lens group, are supported by a unitized finder case, and in this drive mechanism, against the biasing means, The feature is that a worm wheel mechanism for holding the movable variable power lens group at the adjustment position is interposed.

According to the camera zoom finder device having the above configuration,
Only the zoom finder device can be independently attached or detached without disassembling other parts.

Further, when assembling the zoom finder device to the camera body, the zoom finder device can be mounted on the camera body while the movable variable magnification lens group is adjusted and held at the optimum position in the finder case. Since the worm wheel mechanism always engages only one side of the tooth surface by the force of the urging means, the worm wheel mechanism can be driven smoothly without generating vibration or the like.

"Embodiments of the invention" The invention will be described below based on illustrated embodiments. As shown in FIG. 3, the camera body 50 has a lens barrel 51, and a distance measuring device 52 is provided above the lens barrel 51.
A circuit board 53 is provided above the distance measuring device 52. The camera body 50 has a screw hole 55, and a positioning hole 57 is formed in a substrate 56 which is a part of the camera body 50. The unitized zoom finder device 11, which is a feature of the present invention, has a positioning pin 59 fixed to the rear wall in the optical axis direction fitted into a positioning hole 57, and a screw hole of a fixing bracket 58 provided at a front portion thereof. Screw through the screw hole
It is fixed to the camera body by screwing it into 55.

The zoom finder device 11 will be described in detail with reference to FIGS.

The zoom finder device 11 has a unitized finder case 9 composed of a finder lower frame 12, a finder middle frame 13, and a finder upper frame 15. The finder lower frame 12 is located forward (to the left in the figure)
A lens frame 16 having a fixed lens group 14 is formed. Further, lens guide grooves 17 are formed on the left and right inner walls of the finder lower frame 12.

The finder lower frame 12 is formed with a small through hole 19 through which the drive shaft 20 passes. One end of a drive cam lever 22 is non-rotatably mounted by a key or the like inside the finder lower frame of the drive shaft 20. The cam pin 18 is provided at the other end of the driving cam lever 22 in an upward direction. Further, a lens drive lever 26 is pivotally supported by a rotation fulcrum 25 inside the finder lower frame 12 and partially overlaps the drive cam lever 22. The lens drive lever 26 is urged to rotate counterclockwise in the figure by a tension spring 24 (urging means). This lens drive lever
A guide groove 29 is formed at the tip end of 26 along the radial direction centering on the pivot 25, and a guide pin 30 is slidably fitted in the guide groove 29. On one side of the lens drive lever 26, an arc-shaped cam surface 27 that engages with the cam pin 18 is formed. A rotation restricting pin 31 sandwiching the lever 26 from both sides is provided on the rotation locus of the lens drive lever 26.

The lens drive gears 21 and 2
3, and a drive gear train 10 including a lens drive worm gear 28 is provided. The lens driving gear 21 is non-rotatably attached to the outside of the finder lower frame of the driving shaft 20 by a spline or a key. The lens drive worm gear 28 connected to the gear 21 via the lens drive gear 23 is located on the most upstream side in the drive gear train 10, and is connected to a zoom motor as a drive source. Drive cam lever 22, lens drive lever 26, tension spring
24 and a drive gear train 10, a drive mechanism is constituted, and a lens drive gear 23 and a lens drive worm gear 28
Constitutes a worm wheel mechanism.

The movable zoom lens group 33 is fitted into a movable lens holder 44, and guide ribs are provided on the left and right sides of the movable lens holder 44.
35 are provided. The guide rib 35 is placed in the lens guide groove 17 in a state where the guide pin 30 is fitted in the fitting hole formed in the lower surface of the movable lens holder.

The finder middle frame 13 is shaped to cover the upper part of the finder lower frame 12, and a lens frame 36 for fitting the first fixed lens group 14 is formed in the front. Behind, a lens frame 39 for fitting the second fixed lens group 37, and a third fixed lens group
A lens frame 41 into which the lens frame 40 is fitted is formed. Although not shown, a portion corresponding to the lens guide groove 17 of the finder lower frame 12 is provided with left and right guide ribs 35 mounted on the lens guide groove 17.
Is slidably supported.

The finder upper frame 15 is shaped to cover the rear part of the finder middle frame 13. The finder upper frame 15 is the lens frame 39
It has a lens frame 42 for pressing the second fixed lens group 37 fitted on the lens unit from above, and a lens frame (not shown) for pressing the third fixed lens group 40 from above.

 The present zoom finder device 11 operates as follows.

When the zoom motor on the camera body side is driven, the rotation is transmitted to the drive cam lever 22 in the finder case 9 via the lens drive worm gear 28, the lens drive gears 23 and 21, and the drive shaft 20 as input means. .

If this rotation is, for example, in the counterclockwise direction in the figure, the cam pin 18 rotating in the same direction
To rotate the lens drive lever 26 clockwise in the figure. Then, the lens drive lever 26 is moved to the guide pin 30
The movable variable-magnification lens group 33 is moved rearward (rightward in the figure) along the lens guide groove 17 while appropriately sliding in the guide groove 29. Thus, the first fixed lens group 14 and the movable zoom lens group
The distance from the third fixed lens group 40 is changed, and the angle of view in the finder visual field viewed from the third fixed lens group 40 is changed according to the focal length.

When the zoom motor rotates in the opposite direction, the drive cam lever 22 rotates clockwise in the drawing, and the cam pin 18 gradually moves away from the cam surface 27. As a result, the lens drive lever 26 rotates counterclockwise in the figure while the cam surface 27 contacts the cam pin 18 by the urging force of the tension spring 24. Accordingly, the movable zoom lens group 33 is moved forward along the optical axis along the lens guide groove 17, and the angle of view in the viewfinder is changed according to the focal length.

When moving the variable magnification lens 33 in the optical axis direction by driving the drive gear train 10, the lens movable lever 26 always applies the urging force of the tension spring 24 to the transmission upstream side via the lever 22. The lens drive gears 21 and 23 and the lens drive worm gear 28 receive the rotational urging force of the tension spring 24 when rotating in either direction.
For this reason, the gears 21, 23, and 28 rotate in a state where only one side of the tooth surface meshes with each other during the stop and the operation. Thereby, the drive gear train 10 rotates smoothly without generating noise and vibration.

Prior to the mounting work of the zoom finder device 11, the lens drive worm gear 28 is slightly rotated to rotate the drive cam lever 22 counterclockwise, and the lens drive lever 26 is pushed by the cam pin 18, and the lever 26 starts rotating. Hold immediately before (adjustment position). In this state, the worm gear 28 serves as a stopper to prevent rotation caused by the rotation urging force applied via the lens driving gears 23, 21 and the like.
Therefore, before assembling the zoom finder device 11, it is possible to adjust and hold the zoom finder device 11 in a state immediately before moving the variable magnification lens 33. Then, by connecting the lens drive worm gear 28 to a zoom motor as a drive source, the drive timing of the zoom finder device 11 is set appropriately.

In the above embodiment, the present invention was applied to the zoom finder device having only one movable variable power lens group.
The present invention is not limited to this, and may be applied to a zoom finder device having a plurality of movable variable power lens groups.

"Effects of the invention" As described above, according to the zoom finder device of the invention, at the time of inspection, repair, etc., without disassembling other parts,
Only the zoom finder device can be easily attached and detached. Further, prior to the assembling operation, the worm wheel mechanism can be manually rotated to hold the movable variable power lens group at the adjustment position in advance. Further, since the worm wheel mechanism is constantly urged to rotate by receiving the urging force of the urging means, it is possible to smoothly rotate the gear by engaging only one side of the tooth surface thereof.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a zoom finder device according to the present invention, FIG. 2 is an enlarged perspective view showing a finder lower frame portion, and FIG. 3 shows a support structure of a camera body supporting the zoom finder device. It is a perspective view. 9: finder case, 10: drive gear train (drive mechanism), 11: zoom finder device, 12: finder lower frame, 13: finder middle frame, 14: first fixed lens group, 15 ... Finder upper frame, 16 ... Lens frame, 17 ... Lens guide groove, 18 ... Cam pin, 19 ... Through hole, 20 ... Drive shaft, 21 ... Lens drive gear, 23,28 ... Lens drive gear, Lens drive worm gear (worm wheel mechanism), 22, 26 ... drive cam lever, lens drive lever (drive mechanism), 24 ... tension spring (biasing means), 25
… Rotating fulcrum, 27… Cam surface, 29… Guide groove, 30… Guide pin, 33… Movable zoom lens group, 34… Mating hole, 35…
... guide ribs, 37 ... second fixed lens group, 39 ... lens frame, 40 ... third fixed lens group, 41 ... lens frame, 42 ...
Lens frame, 44: movable lens holder, 50: camera body, 51: lens barrel, 52: distance measuring device, 55: screw hole, 56: substrate, 57: positioning hole, 58: Fixing bracket, 59 ... Positioning pin.

Claims (1)

(57) [Scope of request for utility model registration] 1. A zoom finder device having a fixed lens group and a movable zoom lens group, wherein the fixed lens group, the movable zoom lens group, and the movable zoom lens group are biased to move forward or backward in the optical axis direction. And a driving mechanism for driving the movable zoom lens group are supported by a unitized finder case, and a movable variable magnification lens is provided in the driving mechanism against the urging means. A zoom finder device for a camera, comprising a worm wheel mechanism for holding a group at an adjustment position.