JPH04330408A - Lens barrel for tv camera - Google Patents

Abstract

PURPOSE:To perform the tracking adjustment of a lens barrel without using an adjusting washer. CONSTITUTION:A cam barrel 30 is provided in a fixed barrel 10, and a 1st moving barrel 12 and a 2nd moving barrel 14 are moved back and forth by turning the cam barrel 30. Adjusting rings 44 and 48 are screwed in the cam barrel 30. By turning the adjusting ring 48, the tracking adjustment is performed and then the ring 48 is turned to adjust the feeling of operating the cam barrel 30.

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 TV camera.

0002

2. Description of the Related Art Tracking adjustment is performed in a fixed focus lens camera as follows. Multiple adjustment washers are inserted between the fixed barrel and cam barrel to adjust the back focus.

0003

However, the conventional lens position adjustment device described above has a drawback that it takes time to replace the adjustment washer for tracking adjustment. In addition, when an adjustment washer is inserted, the optical axis is tilted, causing optical axis misalignment. Another disadvantage is that the optical characteristics change depending on the tightening force of the mount set screw.

The present invention has been made in view of the above circumstances, and an object of the present invention is to propose a lens barrel for a TV camera in which tracking adjustment can be performed without using an adjustment washer.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a fixed barrel, a lens holding barrel fitted into the fixed barrel so as to be movable in the axial direction, and an outer periphery of the fixed barrel. a cam barrel that is rotatably fitted into the lens holding barrel, has a cam that engages with a cam follower pin that is planted on the outer periphery of the lens holding barrel and that protrudes through a straight groove formed in the axial direction of the fixed barrel; In the lens barrel for a TV camera, the front and rear reference parts are formed on the fixed barrel at a predetermined distance with respect to both the front and rear ends of the cam barrel, and the reference part of the end of the cam barrel or the fixed barrel is formed. The present invention is characterized in that an adjustment ring is provided which is screwed onto one of the cam cylinders and adjusts and maintains the distance between the reference part and the end of the cam cylinder.

[0006]

[Operation] In the present invention, first, the cam cylinder is moved to the front end of the fixed cylinder. Next, rotate the front adjustment ring to gradually move the cam barrel toward the rear, thereby performing tracking adjustment. Next, fix the front adjustment ring with adhesive tape, and in this state rotate the rear adjustment ring to adjust the operating feel of the cam cylinder.

Alternatively, in the present invention, the operating feel of the cam cylinder 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 and perform tracking adjustment. In this case, if the front and rear adjustment rings are rotated by the same amount, the operating feel will not change.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the lens barrel for a TV camera according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a zoom lens barrel to which the TV camera lens barrel according to the present invention is applied, and a fixed barrel 10 has a first movable barrel 12 and a second movable barrel 14 that are slidable in the axial direction. Supported. A first lens group 16 is attached to the first movable tube 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 tube 14 via the lens support frame 18.
6 and 28. Further, a cam cylinder 30 is rotatably supported on the outer periphery of the fixed cylinder 10. The fixed barrel 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 shown) is installed on the outside of the first movable barrel 12 in the radial direction. It passes through and fits into the first cam groove 36 of the cam cylinder 30. The second movable cylinder 14 has a guide pin 3
8 (only one is shown) is planted on the outside in the radial direction, and this guide pin 38 passes through a straight groove 40 formed in the axial direction of the fixed cylinder 10, and also passes through a second cam groove of the cam cylinder 30. It's stuck in 42. Therefore, when the cam cylinder 30 is rotated, the movable cylinders 12 and 14 are moved through the straight grooves 34 and 40.
and the cam grooves 36 and 42 of the cam cylinder 30, so that it can move in the front and rear direction.

As shown in detail in FIG. 2, a recess 10A is formed on the outer periphery of the fixed cylinder 10, and the cam cylinder 30 is located in this recess 10A. An adjustment ring 44 is screwed onto the front outer periphery of the cam cylinder 30 via a threaded portion 46 . Further, an adjustment ring 48 is screwed onto the rear outer periphery of the cam cylinder 30 via a threaded 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 explained in detail. In the present invention, first, the cam cylinder 30 is moved to the front end of the fixed cylinder 10. Next, the front adjustment ring 44 is rotated to gradually move the cam cylinder 30 to the rear, and tracking adjustment is performed at this time. 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 feel of the cam cylinder 30. That is, the operational feel is adjusted by the frictional force caused by the contact between the rear end surface of the adjustment ring 48 and the stepped portion 10B of the fixed cylinder 10. After adjustment, the adjustment ring 48 is fixed with adhesive tape.

Alternatively, in the present invention, the operating feel of the cam cylinder 30 is adjusted by simultaneously rotating the front and rear adjustment rings 44 and 48. Next, the front and rear adjusting rings 44 and 48 are rotated in opposite directions to move the cam cylinder 30 to perform tracking adjustment. In this case, if the front and rear adjustment rings 44, 48 are rotated by the same amount, the operating feel will not change.

[0013]

[Effects of the Invention] As explained above, according to the lens barrel for a TV camera according to the present invention, an adjustment ring is screwed onto the front and rear ends of the cam barrel, and tracking adjustment is performed by rotating this adjustment ring. Therefore, tracking adjustment becomes easy.

[Brief explanation of drawings]

[Fig. 1] Fig. 1 is a sectional view of a lens barrel to which the present invention is applied.

[Fig. 2] Fig. 2 is a sectional view showing the main parts of the present invention.

[Explanation of symbols]

10...Fixed cylinder 12, 14...Movable cylinder 30...Cam tube 44...Front adjustment ring 48...Rear adjustment ring

Claims (1)

[Claims] Claims: 1. A fixed cylinder; a lens holding cylinder fitted into the fixed cylinder so as to be movable in the axial direction; a cam cylinder that is planted and includes a cam that engages with a protruding cam follower pin through a straight groove formed in the axial direction of the fixed cylinder;
In the lens barrel for a TV camera, the front and rear reference parts are formed on the fixed barrel at a predetermined distance with respect to both the front and rear ends of the cam barrel, and the reference part of the end of the cam barrel or the fixed barrel is formed. A lens barrel for a TV camera, characterized in that an adjustment ring is screwed onto one of the ends and adjusts and maintains the distance between the reference part and the end of the cam barrel.