JPH0328420Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a zoom device for a zoom lens for a video or cine camera.

[Conventional technology]

Generally, an electric zoom motor is often used in a zoom device for a zoom lens for a video or cine camera. In this case, a friction transmission mechanism is provided to prevent the motor from burning out when the zoom ring hits the stopper and the rotation angle is restricted. However, the installation of the friction transmission mechanism has the problem of poor operability since the rotational torque of the zoom ring becomes large during manual zoom operation.

Therefore, a manual/electric zoom switching mechanism has been proposed that can improve manual operability. The first is, as described in Utility Model Publication No. 49-20110, a plate that supports a zoom lever that can be raised and lowered on the periphery of the zoom ring, and has a spherical part formed in the center along the inner periphery of the zoom ring. The spherical part of the plate spring is attached to and disengaged from the zoom gear by attaching a spring and raising and lowering the zoom lever. , a zoom lever that can be raised and lowered is pivoted, and by raising and lowering the zoom lever, the zoom gear is moved in the optical axis direction, and the motor output gear and the zoom gear are engaged and disengaged. .

However, all of the above conventional systems are configured so that switching between manual and electric zoom can be performed by raising and lowering the zoom lever.
As video cameras themselves have become more compact in recent years, there has been a problem in applying the above switching mechanism to focus rings whose overall length and maximum diameter have become restricted. That is, when the zoom lever is raised and lowered in the direction of the optical axis, the zoom lever hits the camera exterior cover, which obstructs focus operation and visual inspection of the distance scale on the circumference of the focus ring. When the zoom ring is raised and lowered in the radial direction, there is a problem in that it becomes difficult to grip the zoom lever when performing manual zoom. In particular, as in the first mechanism, switching between manual and electric zoom is possible using a coil spring.
If the zoom gear is connected to and disconnected from the zoom gear via a leaf spring, the stroke required for raising and lowering the zoom lever must be designed to be quite large in order to ensure reliable switching, and the shape of the zoom lever must also be large. I had no choice. Moreover, electric
Since two springs are used for manual zoom switching, the spring pressure and spring flexibility must be managed separately, resulting in an increase in management man-hours.

[Purpose of invention]

This design allows switching between manual and electric zoom without hitting the camera's exterior cover or interfering with focus ring operation and visual viewing of the distance scale on the circumference of the focus ring, and it does not require a large amount of switching stroke of the zoom lever. It is an object of the present invention to provide a zoom device that can reliably switch between manual and electric zoom without having to do so.

[Structure of the idea]

This invention is a zoom device that operates a zoom lens using an electric motor as a drive source, and includes a zoom ring in which an inner cylinder and an outer cylinder are integrated through a front connecting part, and the outer periphery of an extension of the inner cylinder of the zoom ring. To,
A zoom gear having a spur gear that meshes with the output gear of the motor and a bevel gear on its front wall is rotatably fitted into the outer cylinder of the zoom ring without being able to move in the optical axis direction. A zoom lever that can be moved between two points, an inner and outer direction, is provided, and a bevel gear that can mesh with the bevel gear of the zoom gear at the point of inward movement is provided at the inner end of the zoom lever, and both bevel gears are in meshing state. In order to achieve the above purpose, the bevel gear of the zoom lever is configured to rotate independently or together with the zoom lever when the rotation of the zoom ring is stopped while the rotation of the zoom gear continues. This is what I did.

〔Example〕

Next, this invention will be explained based on embodiments shown in the accompanying drawings.

1 and 2 show the first example. In the figures, 1 is a zoom ring, and the inner circumference of the zoom ring 1 has a pin (not shown) fixed to a cam cylinder (not shown). A key groove 2 is provided to fit with the
When the zoom ring 1 rotates, the cam cylinder rotates via the pin, and zooming is performed. This zoom ring 1 is constructed by integrating an inner cylinder 1a and an outer cylinder 1b via a front connecting part 1c.

Reference numeral 3 denotes a zoom gear, and the zoom gear 3 is rotatably fitted between an abutment step 4 provided on the rear outer periphery of the inner cylinder 1a of the zoom ring 1 and a C washer 6 fitted into a circumferential groove 5. and the play in the optical axis direction is regulated. The zoom gear 3 includes a spur gear 3a,
The spur gear 3a meshes with an output gear 7, and the output gear 7 is connected to a zoom motor 9 via a reduction gear unit 8. Incidentally, the reduction gear unit 8 and the zoom motor 9 are attached to fixed parts (not shown) using fixing devices such as machine screws.

10 is a zoom lever, and 11 is a zoom lever receiving portion. The zoom lever receiving part 11 has a male screw part 11a carved on its inner end connected to the outer cylinder 1b of the zoom ring 1.
It is screwed into a female threaded portion 1d' formed on the inner periphery of a circular hole 1d provided on the periphery of the holder. The zoom lever 10 has a knob 10a at its outer end, and a protrusion 10b at its inner end.A bevel gear (inner end gear) is attached to the protrusion 10b when a helical spring (friction spring) 12 is compressed. 13 is fitted, and its outer surface is supported by an E washer 15 fitted into the circumferential groove 14 to prevent it from coming off. The bevel gear 13 is the zoom lever 10
in the axial direction (between two points in the radial direction of zoom ring 1)
By moving the bevel gear 3b of the zoom gear 3, the bevel gear 3b is engaged with and disengaged from the bevel gear 3b of the zoom gear 3. The movement of the zoom lever 10 between two points (it cannot rotate in the circumferential direction) is caused by a click ball 18 attached to the outer end of a click spring 17 fitted into a round hole 16 provided on the outer circumference 10c of the zoom lever 10. Receiving part 1
Click holes 1 drilled at the top and bottom positions of the inner peripheral surface of 1
9a, 19b, the click ball 18 is regulated when it is inserted into the zoom lever receiving part 11.
When fitted into the click hole 19b of the zoom lever 10, the bevel gear 13 of the zoom lever 10 and the bevel gear 3b of the zoom gear 3 mesh (see FIG. 2A), and the click ball 18 fits into the click hole of the zoom lever receiver 11. 19
When fitted to a, the bevel gear 1 of the zoom lever 10
3 and the bevel gear 3b of the zoom gear 3 are separated from each other (see FIG. 2B). Therefore, when operating the electric zoom, the zoom lever 10 is moved toward the axis of the zoom ring 1, and the zoom lever 10
The click ball 18 attached to the outer end of the click spring 17 fitted into the round hole 16 is fitted into the inner click hole 19b of the zoom lever receiving part 11. At this point of inward movement, the bevel gear 13 of the zoom lever 10 engages with the bevel gear 3b of the zoom gear 3. When power is supplied to the zoom motor 9 in this state, the rotation of the zoom motor 9 is transmitted to the zoom gear 3 via the reduction gear unit 8 and the output gear 7. The bevel gear 13 of the zoom lever 10 that is engaged with the bevel gear 3b of the zoom gear 3 is connected to the helical spring 1.
2 is pressed against the E washer 15 by its elastic force, and is integrated with the zoom lever 10 by its friction, so that the rotation of the zoom gear 3 is caused by the bevel gear 13, the zoom lever 10, The signal is transmitted to the zoom ring 1 via the zoom lever receiving portion 11, and the zoom ring 1 is rotated around the optical axis.

Thus, when the rotated zoom ring 1 stops with its rotation angle being regulated by a zoom stopper (not shown) (the rotation end of the zoom ring 1), the bevel gear 13 of the zoom lever 10 is moved by the friction of the helical spring 12. The protrusion 10b of the zoom lever 10
Since the zoom motor 9 will slip and rotate around , it will not burn out even if it continues to rotate.

On the other hand, when operating the manual zoom, the zoom lever 1
0 toward the outside and click ball 18.
When the bevel gear 13 of the zoom lever 10 is disengaged from the bevel gear 3b of the zoom gear 3, the bevel gear 13 of the zoom lever 10 is disengaged from the bevel gear 3b of the zoom gear 3. In this state, if the zoom lever 10 is manually operated to rotate the zoom ring 1 around the optical axis, the zoom ring 1 can be rotated with very light torque without being affected by the friction of the helical spring 12. becomes.

FIGS. 3 and 4 show a second example.

In this case, a screw hole 10b' is provided on the inner end surface of the zoom lever 10, and the bevel gear 13 is fixed by a screw rod 20 screwed into the screw hole 10b'. Click holes in which the click ball 18 of the zoom lever 10 engages are provided as circumferential grooves 19a' and 19b' at the positions. That is, the zoom lever 10 is provided so as to be slidable and rotatable at two points, inside and outside, via a click spring (friction spring) 17. Therefore, during electric zoom operation, the zoom lever 10 is moved toward the axis of the zoom ring 1, and the round hole 16 of the zoom lever 10 is moved toward the axis of the zoom ring 1.
When the click ball 18 attached to the outer end of the click spring 17 fitted with the click ball 18 is fitted into the inner click circumferential groove 19b' of the zoom lever receiving part 11, the bevel gear 13 of the zoom lever 10 is moved to the bevel gear 3b of the zoom gear 3. mesh with. When power is supplied to the zoom motor 9 in this state, the rotation of the zoom motor 9 is transmitted to the zoom gear 3 via the reduction gear unit 8 and the output gear 7.
transmitted to. In this case, the zoom lever 10 is integrated with the bevel gear 13 because the click spring 17 that presses the click ball 18 against the click circumferential groove 19b' maintains sufficient spring biasing force to restrict the rotation of the zoom lever 10. The rotation of the zoom gear 3 is transmitted to the zoom ring 1 via the bevel gear 13 meshing with it, the zoom lever 10, and the zoom lever receiver 11, and the zoom ring 1 is rotated around the optical axis. .

When the rotated zoom ring 1 stops with its rotation angle being regulated by a zoom stopper (not shown), the bevel gear 13 of the zoom lever 10 resists the friction of the click spring 17 and the click ball 18 against the click circumferential groove 19b'. Since the zoom motor 9 rotates together with the zoom lever 10 which slides and rotates, the zoom motor 9 will not burn out even if it continues to rotate.

On the other hand, in manual zoom operation, the zoom lever 10
The zoom ring 1
can be rotated around the optical axis with a very light torque.

[Effect of idea]

As described above, according to this invention, switching between electric zoom and manual zoom can be easily performed by moving the zoom lever in the diametrical direction of the zoom ring. Also, the obstruction to visual inspection of the distance scale on the circumference of the focus ring can be eliminated.

In addition, with this device, the switching stroke is not attenuated by the spring in the switching part, and the switching can be performed reliably only by the stroke of engaging and disengaging the bevel gears, so there is no need for a large switching stroke like in the past. .

Furthermore, according to this invention, in order to prevent motor burnout during electric zooming, there is a connection between the motor reduction unit and the zoom gear as described in Japanese Utility Model Publication No. 49-20110, or a zoom ring as described in Japanese Utility Model Publication No. 46-30058. Since there is no need to provide a spring to generate friction between the zoom gear and the zoom gear, the space in the optical axis direction can be reduced, contributing to compactness. Particularly, as shown in the second embodiment, when the click spring is also used as a friction generating spring and is housed in the zoom lever, various excellent effects such as being more suitable for compactness can be achieved.

[Brief explanation of drawings]

The figures show embodiments of this invention. Figure 1 is an exploded perspective view of the first example, Figures 2A and B are sectional views of the operating state, and Figure 3 is the second example. The exploded perspective view shown in FIGS. 4A and 4B is a sectional view of the operating state. 1...Zoom ring, 3...Zoom gear, 10
...Zoom lever, 11...Zoom lever receiver,
12... Helical spring, 13... Bevel gear, 16...
Round hole, 17...Click spring, 18...Click ball, 19a, 19b...Click hole, 19
a'19b'...Click circumferential groove.

Claims (1)

[Claims for Utility Model Registration] (1) A zoom device that operates a zoom lens using an electric motor as a drive source, comprising a zoom ring in which an inner cylinder and an outer cylinder are integrated via a front connecting part, A zoom gear having a spur gear that meshes with the output gear of the motor and a bevel gear on its front wall is fitted to the outer periphery of the extension of the inner cylinder of the ring so as to be rotatable but not movable in the optical axis direction, and , the outer cylinder of the zoom ring is provided with a zoom lever that can be moved between two points in the radial direction, the outside and the outside, and the inner end of the zoom lever is provided with a bevel gear that can mesh with the bevel gear of the zoom gear at the point of inward movement. The bevel gear of the zoom lever can be rotated independently or together with the zoom lever when the zoom ring stops rotating while both bevel gears are in mesh and the zoom gear continues to rotate. A zoom device characterized by: (2) The zoom device according to claim 1, wherein the bevel gear on the zoom lever side is slidably and rotatably supported via a friction spring on the zoom lever that does not rotate in the circumferential direction at the inward/outward movement point. . (3) The bevel gear on the zoom lever side is fixed to the inner end surface of the zoom lever, which is provided so as to be able to slide and rotate in the circumferential direction via a friction spring at an inward/outward moving point via a friction spring. zoom device.