JP3010564B2 - Lens barrel for TV camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a TV camera, and more particularly to a lens barrel for a TV camera used for tracking adjustment of a fixed focus lens used in a television camera.

[0002]

2. Description of the Related Art In a camera having a fixed focus lens, tracking adjustment is performed as follows. The back focus is adjusted by inserting a plurality of adjustment washers between the fixed cylinder and the cam cylinder.

[0003]

However, the conventional lens position adjusting device has a drawback that it takes time to change an adjustment washer for tracking adjustment. In addition, when the adjustment washer is inserted, the optical axis is tilted, and there is a disadvantage that the optical axis is shifted. Further, there is a disadvantage that the optical characteristics are changed by adjusting the tightening force of the mounting screw.

The present invention has been made in view of such circumstances, and an object of the present invention is to propose a lens barrel for a TV camera capable of performing tracking adjustment without using an adjustment washer.

[0005]

According to the present invention, there is provided a movable cylinder holding a fixed barrel and a lens, the movable barrel being fitted in the fixed barrel so as to be movable in the axial direction. Fixed cylinder
Is rotatably supported on said movable barrel and the cam engagement movement barrel
A cam cylinder for regulating the movement of the TV camera lens barrel in which and a reference portion of the front and rear formed in the fixed cylinder at a predetermined distance with respect to the front and rear end portions of the cam cylinder, one of the cam cylinder is screwed into one of the reference portion of the end portion or the fixed cylinder, the first adjustment ring for adjusting maintain the distance between one end of the reference portion and the cam tube, the other end portion of the cam cylinder
Is screwed into and fixed to the fixed cylinder
The operation feeling of the cam barrel is adjusted by applying frictional force.
And a second adjusting ring to be provided.

[0006]

According to the present invention, first, the cam barrel is moved to the front end of the fixed barrel. Next, the front adjustment ring is rotated to gradually move the cam cylinder to the rear side, thereby performing tracking adjustment.
Next, the front adjustment ring is fixed with adhesive tape, and in this state, the rear adjustment ring is rotated to adjust the operational feeling of the cam barrel.

Alternatively, in the present invention, the operating feeling of the cam barrel is adjusted by simultaneously rotating the front and rear adjustment rings. Next, the front and rear adjustment rings are rotated in opposite directions to move the cam cylinder to perform tracking adjustment. In this case, if the front and rear adjustment rings are rotated by the same amount, the operational feeling does not change.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a lens barrel for a TV camera according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a zoom lens barrel to which a lens barrel for a TV camera according to the present invention is applied, and a fixed barrel 10 has a first movable barrel 12 and a second movable barrel 14 slidably in the axial direction. Supported. A first lens group 16 is attached to the first movable barrel 12 via a lens support frame 18, and a second lens group 22 and a third lens group 24 are attached to the second movable barrel 14.
It is attached via 6, 28. A cam cylinder 30 is rotatably supported on the outer periphery of the fixed cylinder 10. The fixed cylinder 10 is fixed to a mount portion of a camera body (not shown) by a flange provided at the right end in FIG.

A guide pin 32 (only one is shown) is erected outside the radial direction in the first movable cylinder 12. The guide pin 32 has a straight groove 34 formed in the axial direction of the fixed cylinder 10. It penetrates and fits into the first cam groove 36 of the cam cylinder 30. The second moving cylinder 14 has a guide pin 3
The guide pin 38 penetrates the straight groove 40 formed in the axial direction of the fixed cylinder 10, and the second cam groove of the cam cylinder 30. It fits into 42. Therefore, when the cam barrel 30 is rotated, the movable barrels 12 and 14 are brought into the straight grooves 34 and 4.
0 and the cam grooves 36 and 42 of the cam cylinder 30 to move in the front-rear direction.

As shown in detail in FIG. 2, a recess 10A is formed in the outer periphery of the fixed barrel 10, and the cam barrel 30 is located in the recess 10A. An adjusting ring 44 is screwed to the front outer periphery of the cam cylinder 30 via a screw portion 46. An adjusting ring 48 is screwed onto the rear outer periphery of the cam cylinder 30 via a screw portion 50. A rubber cover 52 is attached to the outer periphery of the cam cylinder 30.

The operation of the lens barrel for a TV camera according to the present invention, constructed as described above, will be described in detail. In the present invention, first, the cam barrel 30 is moved to the front end of the fixed barrel 10. Next, the front adjustment ring 44 is rotated to gradually move the cam barrel 30 rearward, and at this time, tracking adjustment is performed. Next, the front adjustment ring 44 is immovably fixed using an adhesive tape (not shown), and in this state, the rear adjustment ring 48 is rotated to adjust the operational feeling of the cam barrel 30. That is, the operational feeling is adjusted by the frictional force caused by the contact between the rear end face of the adjusting ring 48 and the step portion 10B of the fixed cylinder 10. After the adjustment, the adjustment ring 48 is fixed with an adhesive tape.

Alternatively, in the present invention, the operation feeling of the cam barrel 30 is adjusted by simultaneously rotating the front and rear adjustment rings 44 and 48. Next, the front and rear adjustment rings 44 and 48 are rotated in opposite directions to move the cam cylinder 30 to perform tracking adjustment. In this case, when the front and rear adjustment rings 44 and 48 are rotated by equal amounts, the operational feeling does not change. In the examples,
Shows an example in which the adjusting ring 44 is screwed on the cam cylinder 30 side.
However, the present invention is not limited to this.
The screw 44 may be screwed on the reference portion of the fixed cylinder 10.

[0013]

As described above, according to the lens barrel for a TV camera according to the present invention, an adjustment ring is screwed into the front and rear ends of the cam barrel, and tracking adjustment is performed by rotating the adjustment ring. Therefore, tracking adjustment becomes easy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lens barrel to which the present invention is applied;

FIG. 2 is a sectional view showing a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Fixed cylinder 12, 14 ... Moving cylinder 30 ... Cam cylinder 44 ... Front adjustment ring 48 ... Rear adjustment ring

Claims (1)

(57) [Claims] And 1. A fixed cylinder, holding the lens, and the movable cylinder which is fitted movably in the axial direction in the fixed cylinder is rotatably supported in the fixed cylinder, the movable cylinder and the cam engagement
A cam barrel for restricting the movement of the moving barrel; and a lens barrel for a TV camera comprising: a front and rear reference part formed on a fixed barrel at a predetermined distance from both front and rear ends of the cam barrel; is screwed into one of the reference portion of the one end portion or the fixed cylinder of the cam barrel, the first adjustment ring for adjusting maintain the distance between one end of the reference portion and the cam barrel, the cam cylinder Screwed to the other end and rotated
The cam is brought into contact with the fixed cylinder by applying frictional force.
A lens barrel for a TV camera , comprising: a second adjusting ring for adjusting a feeling of operation of the cylinder.