JPH0442826Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a lens attachment mechanism for a video camera.

(B) Prior art The applicant previously proposed the technology of Utility Model Application No. 1983-57795 for a lens mounting mechanism that enables close-up photography by adjusting the lens barrel of a video camera so that it can move forward and backward. .

This idea involves screwing a medium-diameter adjustment ring, which rotatably stores a small-diameter mount ring that screws onto the lens barrel, onto the inner circumference of a large-diameter guide ring that is fixed to the video camera body. This mechanism is characterized by supporting the lens barrel so that it can be moved back and forth in accordance with the amount of screw engagement of the adjustment ring. According to this mechanism, the lens barrel can be moved back and forth continuously.

(c) Problems to be solved by the invention However, although the above-mentioned conventional example can accommodate all close-up conditions, it is almost difficult to set the lens barrel at a predetermined position according to a preset close-up condition. Therefore, the workability is poor.

(d) Means for Solving the Problems Therefore, the present invention provides a medium-diameter guide ring that is fixed to a video camera and has a plurality of locking portions with different lengths in the optical axis direction on its inner peripheral surface. , a lens mounting mechanism is formed by a small-diameter mount ring that fixes the lens barrel and is selectively locked to the locking portion, and a large-diameter fixing ring that screws into the guide ring and fixes the mount ring. It is characterized by configuring.

(e) Effect According to the present invention, the position of the lens barrel can be changed in stages by simply rotating the mount ring and changing its locking state.

(F) Examples The present invention will be described below with reference to examples that illustrate the present invention.

First, in the embodiment shown in FIGS. 1 and 2, a medium-diameter guide ring 1 fixed to a video camera 4 is shown.
On the other hand, when a small-diameter mount ring 2 to which a lens barrel (not shown) is fixed is inserted, the insertion positions are set at four specific positions. This setting is determined by how the protrusions 2a, 2a, 2a of the mount ring 2 are inserted into the four sets of grooves 1a in the guide ring 1.
In order to realize selective setting in this way, protrusions 2a, 2a,
2a are formed equiangularly, and the four sets of grooves 1a... formed on the inner periphery of the guide ring 1 are also formed equiangularly, but the lengths of the grooves 1a... are different for each group. ing. Three sets of grooves 1a in the guide ring 1...
are formed shorter than the guide ring 1, and the lengths of the grooves 1a are different for each set.
Therefore, the mount ring 2 has its protrusions 2a, 2
When the ends 2b, 2b, 2b of the grooves 1a, 2a are engaged and inserted into the selected grooves 1a, 1a, 1a of the guide ring 1, the ends 1b, 2b of the grooves 1a, 1a, 1a,
By being locked to 1b, 1b, the amount of insertion is determined. A large-diameter fixing ring 3 fixes the mount ring 2 defined in this way.
In order to fix the flange 2c formed on the front outer periphery of the mount ring 2 so as not to come off, a rib 3a facing the flange 2c is formed on the front inner periphery of the fixing ring 3 which is screwed onto the outer periphery of the guide ring 1.

Therefore, according to the embodiment, the mount ring can be defined in three specific positions in stages for close-up photography.

In the above-mentioned embodiment, the mount ring has a protrusion and the guide ring has a groove, but the same effect can be obtained by forming a groove on the mount ring and a protrusion on the guide ring.

Furthermore, various means can be considered for locking the mount ring. For example, mount ring 2
A stepped groove 2d as shown in FIG. 3 is provided on the outer periphery of the
2d, 2d may be formed equiangularly, and an engaging pin that engages with this groove may be engaged with the inner periphery of the guide ring 2. This configuration has the advantage that there is no need to remove the fixing ring every time the close-up state is changed, and the mount ring can be positioned at a predetermined position by simply loosening the fixing ring and rotating the lens barrel. . The reason why the ends of the groove in FIG. 3 are made wide is to make it easier for the pin to engage with the groove during assembly.

(g) Effects of the invention Therefore, according to the invention, the mount ring can be selectively fixed at a specific position, so fine adjustments are not required during close-up photography, and the effect is great.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a lens mount showing one embodiment of the present invention, FIG. 2 is an assembled perspective view of the same, and FIG. 3 is a side view of a mount ring showing another embodiment. 1...Guide ring, 2...Mount ring,
3...Fixing ring, 4...Video camera.

Claims (1)

[Claims for Utility Model Registration] In a lens mounting mechanism that enables close-up photography by attaching a lens barrel to a video camera mount so that it can move forward and backward, A medium-diameter guide ring is formed with a plurality of locking parts of different lengths, a thread is formed on the outer peripheral surface, a thread is formed on the front inner periphery, and a thread is formed on the front inner periphery, and a thread is formed on the front outer periphery. a small-diameter mount ring forming a flange and forming a protrusion selectively abutting the locking part at the rear; a flange facing the flange on the inner periphery of the front; A lens mounting mechanism consisting of a large diameter fixing ring that forms a screw to be screwed together, and a lens mounting mechanism.