JPS6098411A - Zoom driving mechanism of zoom lens barrel for video camera - Google Patents

Abstract

PURPOSE:To prevent generation of uncomfortable sound by inserting the head part of the pin of a cam barrel into the hollow part formed in the stem part of a stopper member provided to a zooming ring, loading a spring, etc. into the spacing between the head part of the pin and the stem part and disposing a cushion material in the part which contact with the long groove end of the stem part and a macro plate. CONSTITUTION:The head part of the pin 4' of a cam barrel 3 is inserted into the hollow part formed to the stem part 8b of a stopper member 8. One end of a stem part 8b is projected outward at all times by the energizing force of a spring 9' loaded in the hollow part. A cushion material 5' is wound on the part of the stem part 8b which contacts with the long groove ends 11, 12 and this part slides in the long groove 6a'. Therefore if the zooming ring 7 is rotated in a tele direction, the material 5' and the end 11 contact with each other and when said ring is rotated in a wide direction, said material contacts with the end of a macro plate 10. When the fine diameter part of the stem part 8b is inserted into a notch 10a by pushing said part, the ring 7 can be further rotated up to the macro end and the material 5' contacts with the long groove end 12. Since the cushion material is always intervened in the contact part in the above-mentioned way, generation of uncomfortable noise is obviated and since just one groove of the lens barrel is required, the reliability interms of strength is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zoom drive mechanism for a zoom lens barrel for a video camera.

Conventional zoom diagram for video cameras with macro function (a)
, as shown in (b), the front group a constituting the zoom lens system
is the first lens holding frame] +i, and the rear group constituting the zoom lens system is held by the second lens holding frame 1b, and the first and second lens holding frames 1a,
lb indicates three guide bars 2 extending in the optical axis direction of the lens ftL tube (only one is shown in the figure).
It is supported at three points and is slidable in the optical axis direction.

Furthermore, guide bins 2a and 2b are implanted on the outer peripheral surfaces of the first and second lens holding frames 1a and lb.

The guide pins 2a, 2b are slidably fitted into cam grooves 3a, 3b formed in the cam cylinder 3.

Further, the pin 4 implanted in the cam barrel 3 has a buffer material 5 wrapped around its outer surface, and the pin 4 is bored around the optical axis of the lens barrel 6 fitted into the cam barrel 3. It passes through a long groove 6a, and its head is fixed to a zooming ring 7 rotatably fitted onto the outer peripheral surface of the lens barrel 6. The zooming ring 7 includes
An operable switch member 8 is disposed, and the stopper member 8 is arranged such that the stopper member 8 is
tl OL l-J, +W A% tl sr:
4k 1w M 1 1-y It is pivotally supported in the thrust direction by the bearing part 8a, and is urged outward by a spring 9 elastically loaded between it and the zooming ring 7, and one end of the shaft part 8b is always directed outward. It stands out.

Further, a collar portion 8c is provided at the other end of the shaft portion 8b,
As shown in FIG. 1(a), the zooming ring 7 is Te1
When rotated to the e side, the flange 8C moves between the zooming ring 7 and the lens barrel 6, and in the Wide position, the flange 8C is a macro plate attached to the lens barrel 6.

10. Therefore, in order to further rotate the zooming ring 7 from the Wide position to the macro side, the shaft 8b is pushed into the lens barrel and the flange 8C is inserted into the short groove 6b drilled in the lens barrel 6. As shown in FIG. 2, the edge of the plate 10 is provided with a rectangular notch [Oa] which is wider than the shaft portion 8b.
If the zoom ring 7 is inserted into the macro side, the zoom ring 7 can be rotated to the macro side.

Therefore, when performing a zooming operation on a conventional zoom lens barrel for a video camera, the zoom ring 7 is rotated around the optical axis to move the zoom lens group in the optical axis direction. As shown in a), Te1. e
At the end, one end 11 of the long groove 6a is formed on the pin 4 and the lens barrel 6.
, At the wide end, the collar part 8c of the soba member 8 and the mouth plate 10. At the macro end, the pin 4 and the other end 12 of the long groove 6a contact each other, so that Te1s, Wide
, the positional relationship of the macro ends is maintained.

However, since it is extremely difficult mechanically and space-wise to provide a buffer to the flange 8c of the stopper member 8 or the macro plate 10 itself, when the zooming ring 7 is operated at the 1 Lidc end, the part The direct contact between the two cameras produced an unpleasant sound, which made the photographer feel uncomfortable and caused blur.

The present invention has been made in view of these problems, and provides a zoom drive mechanism that eliminates the above-mentioned unpleasant noise with a simple configuration and also improves the strength and reliability of the entire lens barrel. We aim to provide the following.

An embodiment of the present invention will be described below with reference to the drawings. still,
Regarding the same members as those explained in the conventional example,
The same reference numerals will be given and the explanation will be omitted.

In this embodiment, the long groove 6a and the short groove 6b bored in the conventional example 115i6 are made common, and the pin 4 and the stopper member 8 are made into an integral structure. That is,
The head of the pin 4' implanted in the cam cylinder 3 is inserted into a hollow part formed in the axis of the shaft part 8b of the stopper member 8, and a spring 9' is inserted into the hollow part. One end of the shaft portion 8b always protrudes outward due to the biasing force of the spring 9'. Further, - the long groove end 11 of the shaft portion 8b
A cushioning material 5' is wrapped around the part that contacts the lens barrel 6 to prevent unpleasant noise from occurring, and the part around which the cushioning material 5' is wrapped is a hole in the lens barrel 6. Long groove around optical axis 6
It can be slid to a'.

Therefore, when performing a zooming operation in this embodiment, as shown in FIG. 2(a), the zooming ring 7 is
When rotated in the direction, the l of the shaft portion 8b at the Te1e end
When the part where the shock material 5' is wound and the long row 11 of the lens barrel 6 are rotated again, the W
At the ide end, the portion where the cushioning material 5' is wound comes into contact with the end of the macro plate 10, and then the shaft portion 8b is pushed in and the narrow diameter portion of the shaft portion 8b is inserted into the hole of the macro plate 10 as described above. The zooming ring 7 inserted into the cutout 10a further includes:
It becomes possible to rotate to the macro end, and the portion where the buffer material 5' is wound comes into contact with the long groove end 12 of the 'th barrel 6.

In this way, the zoom drive mechanism according to the present invention
Because there is always a cushioning material in place at the contact point during the zooming rotation operation of the end, 1ljde end, and macro end, there is no direct contact between the members and the generation of unpleasant noises, and compared to conventional ones, Since only one groove is required to be drilled in the lens barrel, the effects are significant, such as improving the strength and reliability of the lens barrel itself.

[Brief explanation of the drawing]

Figures 1 (a) and 1 (b) are cross-sectional views perpendicular to the optical axis and parallel cross-sectional views of the optical axis of a zoom lens barrel showing a conventional example;
The figure is a partially enlarged view showing the relationship between the shaft part of the stopper member and the macro plate, and FIGS. 1(a) and 1(b) are cross-sectional views perpendicular to the optical axis of the zoom lens barrel according to the present invention and the optical axis. FIG. a...Front group b constituting the zoom lens system...Rear group 3 constituting the zoom lens system...cam tubes 3a, 3b...cam) 4...pins 5, 5'
- Ribbon shock member 6... Lens barrel 6a+6a'... Long groove 7... Zooming ring 8... Stopper member 8a... Bearing part 8
b...Shaft part 8c...Flame part 10...Macro plate Ca) Concave I-shaped

Claims (1)

[Claims] A zoom lens barrel having a cam barrel having a cam groove for moving a movable lens group in the optical axis direction to perform zooming, and a zooming ring for rotating the cam barrel from outside the lens barrel. The head of the pin implanted on the outer surface of the cam cylinder is inserted into the hollow formed in the shaft of the stopper member disposed in the bottle, and a spring or the like is inserted between the head of the bottle and the shaft. 1. A zoom drive mechanism characterized in that a shock absorbing material is provided at the long groove end of the shaft portion and at a portion that contacts the macro plate.