JPS5878133A - Aperture mechanism of optical instrument - Google Patents

Abstract

PURPOSE:To control an aperture easily and exactly, by alternately turning 2 concentric frames for controlling a sector, as to an aperture mechanism of a microscope, etc. CONSTITUTION:A frame 3 turns through a pinion 7 turned electrically, a click spring 5 formed as one body with the frame 3 moves, and the aperture opening becomes large. Subsequently, a frame 1 turns with a pin 1b of the frame 1 being concentrical with the frame 3, through a slot 3b of the frame 3. As a result, a gear 1d of the frame 1, which has not been engaged with the pinion by a non- tooth part 1d' is engaged with the pinion 7, and as for a gear 3d of the frame 3, its engagement with the pinion is detached by a non-tooth pard 3d'. As a result, the frame 3 stops, the frame 1 provided with a click spring 4 turns, and the aperture is closed gradually from the maximum opening. By turning in one direction by alternate turning of said 2 concentric frames, the aperture is controlled easily and exactly.

Description

[Detailed description of the invention] This is related to the mechanism.

This type of conventional aperture mechanism rotates the operating member back and forth within a certain rotation angle range. Since the diaphragm blades were opened and closed by the diaphragm, electric drive of this diaphragm mechanism required a device to detect the maximum aperture position and minimum aperture position to prevent damage to the diaphragm and mechanism, and it was necessary to turn off the power.
To drive the electric motor again in vain, a structure is required to automatically return the aperture blades to the maximum aperture position or the minimum aperture position in order to stabilize the rotational direction of the electric motor, and such a control mechanism becomes extremely complicated. There was a problem.

In view of the above-mentioned problems, the present invention enables continuous rotation of the aperture blades in one direction to continuously open and close the aperture blades.
When electrifying the aperture mechanism, there is no need for a device to detect the maximum and minimum aperture positions of the aperture blades, and it is also possible to turn off the power.
The purpose is to provide an aperture mechanism that eliminates the need for a structure that later automatically returns the aperture blades to the maximum aperture position or the minimum aperture position, thereby making the control mechanism extremely simple. To explain this based on an example, 1 includes a plurality of pivot holes 1a that are mounted on a ψ body (not shown) or the like and are provided at equal positions so as to be able to rotate around the optical axis 0. A fixed frame having a pin 1b implanted at a predetermined position, four click holes 1c provided at quarterly positions, and a toothed portion 1d having four missing toothed portions 1d' on the outer periphery. (See Fig. 3), 2 is a pivot pin 2 arranged at a symmetrical position centering on the optical axis O and implanted on one side □.
a is inserted into the pivot hole 1a, and a sliding pin 2 is attached to the other surface.
A plurality of diaphragm blades 3 are implanted with b, and 3 are fitted into the fixed frame 1 so as to be rotatable around the optical axis 0, and are provided at equal positions and slide together with the sliding pins 2b. The fixing frame 1 is provided with a plurality of radial grooves 3a and at predetermined positions, and is slidably engaged with the pin 1b.
Arc-shaped slot that keeps the range of relative rotation constant) 3
b and four click holes 3c provided in quarter positions, and a tooth portion 3d having four missing teeth portions 3d' on the outer periphery.
is provided with a movable frame (see Fig. 4), and the click holes 1c and 3c are engaged with the click holes 1c and 3C of the fixed frame l and the movable frame 3, respectively, in the toothless area. A click hole provided with protrusions 4a and 5a, 6
7 is an electric motor fixed to a lens barrel, etc. (not shown), and 7 is an electric motor 6.
This is a pinion that is fixed to the drive shaft of and meshes with the teeth 1d and 3d of the fixed frame 1 and the movable frame 3.

Next, the operation of the aperture mechanism according to the present invention will be explained based on FIGS. It is illustrated by a broken line at a position away from part 3d. First, in FIG. 5, the pinion 7 is rotated in the direction of arrow A by the electric motor 6, and since the pinion 7 is meshed with a portion 3d of the movable frame 3, the movable frame 3 is rotated in the direction of arrow B. It moves me. -, since the part of the fixed frame l facing the pinion 7 is the toothless part 1d', the fixed frame l has the click hole 1c.
is stopped by engaging with the projection 4a of the click spring 4. Therefore, since the movable frame 3 rotates relative to the fixed frame 1, the aperture blades 2 are moved from opening to closing or from closing to opening. Next, as shown in FIG. 6, when the last tooth of the first part 3d of the movable frame 3 begins to mesh with the pinion 7 and reaches the line connecting the center axes of the movable frame 3 and the pinion 7, the movable frame 3 slot) One end of 3d is bin 1 with identification frame l
Since the fixed frame 1 is pressed against the point b, the fixed frame 1 also starts rotating in the direction of the arrow B at the same time. Therefore, as shown in FIG. 7, the click hole IC of the fixed frame 1 is disengaged from the protrusion 4a of the click spring 4, and the first tooth of the tooth portion 1d begins to mesh with the pinion 7. On the other hand, the movable frame 3 is rotated in advance by the pinion 7 because the component of the pressing force of the click nut 5 acts as a rotational force just before the last tooth of the tooth portion 3d disengages from the pinion 7. Missing tooth part 3 d' is pinion 7
The click hole 3C engages with the protrusion 5a of the click spring 5 at a position facing the click spring 5, whereby the click hole 3C is stopped.

Therefore, since the fixed frame 1 rotates relative to the movable frame 3, the aperture blades 2 are moved from closed to open or from open to closed in the opposite manner to the above. Then, when the fixed frame 1 has rotated once, the fixed frame 1 is again locked by the projection 4a of the click catch 4, and the movable frame 3 is disengaged from the projection 5a of the click catch 5 and rotated. The operation of the blade 2 from opening to closing or from closing to opening is repeatedly and continuously performed.

In this embodiment, while the fixed frame 1 and the movable frame 3 each make one rotation, the aperture blades 2 perform a continuous operation of open→close→open or close→open→close four times.

In addition, the toothless parts 111I' and 3 of the fixed frame 1 and the movable frame 3
Number of d' and corresponding slot) Length of 3b.

By appropriately selecting the diameter of the pinion 7 and the positions of the click holes 1c and 3C, the aperture blades 2 can be opened and closed an arbitrary number of times per rotation of the fixed frame 1 and the movable frame 3.

Furthermore, the present invention is not limited to the above-mentioned embodiments, but, for example, the fixed frame and the movable frame may each be connected to a motor, and the aperture blades may be opened and closed by alternately and intermittently controlling the fixed frame and the movable frame. You can also do it.

Alternatively, the aperture blades may be opened and closed by alternately meshing a pinion connected to the electric motor with the teeth of the fixed frame and the teeth of the movable frame.

As described above, the diaphragm mechanism according to the present invention can continuously open and close the diaphragm by continuous rotation in one direction. Therefore, even when the diaphragm mechanism is motorized, a device for detecting the maximum aperture position and the minimum aperture position of the diaphragm, etc. is required.・Does not require, and can be powered off
A structure for automatically returning the diaphragm blades to the maximum aperture position or the minimum aperture position afterwards is also unnecessary, and the control mechanism becomes extremely simple.

Furthermore, when controlling the position of the aperture using a servo mechanism or the like, continuous rotational drive in one direction is possible, so the response is quick and the life of the motor is extended. In addition, since the diaphragm can be opened and closed simply by continuous rotation in one direction, it is easier to operate even in manual operation, greatly improving operability, and it is possible to open and close the diaphragm by simply rotating it continuously in one direction. It is also possible to reverse the movement of the aperture.

[Brief explanation of drawings]

FIG. 1 shows a vertical section of an embodiment of the aperture mechanism according to the present invention.
Fig. 2 is a perspective view of the above embodiment, Figs. 3 and 4 are plan views of the fixed frame and movable frame of the above embodiment, respectively, and Figs. 5 to 7 are diagrams showing the operating principle of the above embodiment. It is. 1...Fixed frame, 2...Aperture blade, 3...Movable frame,
4, 5...Kritsuku no None, 6...Electric motor, 7...
・Pinion. Figure 11 Figure 2

Claims (1)

[Claims] A fixed frame that pivotally supports pins implanted on one surface of each of the plurality of aperture blades, and a pin that is arranged concentrically with the fixed frame and implanted on the other surface of the aperture blades, and slidably holds the pins. 1. A diaphragm mechanism for an optical device having a movable frame that opens and closes the diaphragm blades by alternately rotating the fixed frame and the movable frame.