JPH0536411U - Zoom lens barrel - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure smooth zoom operation without being damaged or damaged by shock when the zoom pin fitted in the zoom cam is strong against shock from the tip and accidentally collided. You can A total length is changed by reciprocating movement of the first lens group L1 and L2 in the optical axis direction during zooming, and a moving member 2 that engages with a holding member 1 that holds the first lens group and an optical axis When the first lens group is closest to the camera body when the first group lens is closest to the camera ring, the distance between the drive ring 5 that rotates to the left and the driving ring 5 that drives the holding member 1 via the moving member 2 is small. It is set such that when they receive a force from the front end direction of the first lens group, they come into contact with each other to serve as stoppers.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a zoom lens barrel.

[0002]

[Prior Art]

 Conventionally, as this type of zoom lens barrel, there is known a type in which the first group of lenses has an optical system that reciprocates in the optical axis direction (hereinafter referred to as a U-turn), and its total length changes by zooming. It is widely used because of its relatively simple structure, small size, and inexpensive manufacturing.

[0003]

[Problems to be solved by the device]

 However, the above-described conventional zoom lens barrel is vulnerable to a shock from the tip of the lens barrel due to its structure. For example, when the tip accidentally collides with something, it is fitted into the zoom cam. Sometimes the zoom pin was bent due to shock, or it was damaged and zoom operation could not be performed smoothly.

The present invention has been made in view of the above conventional problems, and always performs a smooth zoom operation against an impact from the tip end without damaging the zoom cam or the zoom pin. An object of the present invention is to provide a zoom lens barrel capable of

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the zoom lens barrel according to the present invention is a zoom lens barrel in which the first group lens reciprocates in the optical axis direction during zooming to change the overall length. The distance between the moving member engaged with the holding member for holding and the drive ring rotating about the optical axis to drive the holding member via the moving member in the optical axis direction is set by the first group lens. When the camera is closest to the camera body, a small gap is provided during normal zooming, and when a force is applied from the front end direction of the first group lens, they come into contact with each other to serve as stoppers.

[0006]

[Action]

 According to the present invention, the distance between the moving member and the drive ring in the optical axis direction is set so as to abut only when a shock is applied from the direction of the tip of the lens barrel. Even when a shock is applied from the direction of the tip of the lens barrel, almost no shock is transmitted to the zoom pin fitted into the zoom cam. Therefore, the zoom pin will not be bent or damaged by the shock, and the zoom operation can always be performed smoothly. Moreover, since the moving member and the drive ring are members that are also used in the conventional lens barrel, there is no need to increase the cost.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings and the like. FIG. 1 is a diagram showing a movement of an optical system during zooming of an embodiment of a zoom lens barrel according to the present invention. FIG. 2 is a vertical cross-sectional view showing a zoom lens barrel according to an embodiment. The upper cross-sectional view shows a state in which the focal length is on the wide side (the range indicated by W in the figure), and the lower cross-sectional view. The cross-sectional view is a view showing a state where the focal length is middle (range shown by M in the figure). FIG. 3 is a cam diagram of the zoom lens barrel according to the example.

First, the movement of the optical system during zooming of the lens barrel of this embodiment will be described. In FIG. 1, the horizontal axis indicates the distance in the optical axis direction of the lens barrel, and the right side in the figure is the camera body side. The vertical axis indicates the zooming state, W indicates the wide side, M indicates the middle position, and T indicates the tele side. A curve a shows the movement of the first lens group, and a straight line b shows the movement of the second lens group.

As shown in FIG. 1, the first lens group moves from the wide side to the middle position along the optical axis to the camera body side, and from the middle position to the tele side. Then, it moves along the optical axis to the tip of the lens barrel, and makes a U-turn with the focal length at the apex of the middle position. That is, the focal length moves from the wide side to the middle position along the optical axis toward the camera body by the distance indicated by L.

The second group lens moves linearly along the optical axis toward the tip of the lens barrel from the wide side to the tele side.

Next, the configuration of the lens barrel according to this embodiment will be described with reference to FIG. In FIG. 2, L1 and L2 are first group lenses, and L3, L4, and L5 are second group lenses. The first group lens holding frame 1 is a frame that holds the first group lenses L1 and L2 at its inner peripheral portion. In this first group lens holding frame 1, a female helicoid 1b is provided on the inner peripheral portion of the large-diameter portion 1a, and a male helicoid 2a provided on the outer peripheral portion of the first group lens moving frame 2 is screwed. ing. Further, a projection 1c is provided on the right end of the outer peripheral portion of the first group lens holding frame 1 in a radially outward direction, and the projection 1c and the optical axis provided on the inner peripheral portion of the manual ring 3 are provided. It engages with the parallel guide grooves 3a.

As described above, the male helicoid 2a is provided on the outer peripheral portion of the first lens group moving frame 2. The inner diameter portion 2d of the first lens group moving frame 2 is fitted to the outer peripheral portion 4c of the small diameter portion 4a of the fixed barrel 4. A zooming cam groove 2b is provided in the center of the first lens group moving frame 2, and a cam composed of a zoom pin 6d fixed to the cam ring 5 by a nut 6c, a color 6a, and a lid 6b. Follower 6 is inserted. Further, in the center of another angular position of the first lens group moving frame 2, there is provided an inner groove 2c parallel to the optical axis, and a pin 7a and a collar 7b which are planted in the fixed barrel 4 are provided. The linear guide pin 7 configured as described above is fitted therein. Therefore, the first lens group moving frame 2 can move in the optical axis direction, but cannot rotate about the optical axis.

The manual ring 3 is provided with a guide groove 3a which is parallel to the optical axis on its inner peripheral portion. As described above, the projection 1c provided radially outward on the outer peripheral portion of the first group lens holding frame 1 is fitted in the guide groove 3a. Therefore, the manual ring 3 and the first group lens holding frame 1 are integrally rotated about the optical axis.

A circumferential groove 3b is provided in the center of the manual ring 3, and a top 8 fixed with a machine screw 9 is fitted into the inner circumference of the large diameter portion 4b of the fixed barrel 4. ing. Therefore, the manual ring 3 can rotate about the optical axis, but cannot move in the optical axis direction. Further, a segment gear 3d is provided on the right inner peripheral portion of the manual ring 3.

In the fixed barrel 4, a cam ring 5 is rotatably fitted to the inner peripheral portion of the small diameter portion 4a. A circular groove 4e having a predetermined angle with respect to the optical axis is provided at the center of the small diameter portion 4a, and the circular groove 4e is fixed to the outer peripheral portion of the cam ring 5 with a small screw 12. The key 11 which has been engaged is engaged. Therefore, the cam ring 5 can rotate about the optical axis, but cannot move in the optical axis direction.

A guide groove 4f parallel to the optical axis is provided to the right of the circumferential groove 4e, and the zoom pin 13 and the collar 14 of the zoom pin 13 and the collar 14 that are planted on the outer peripheral portion of the second lens group moving frame 15 are provided. The tips are engaged. Therefore, the second lens group moving frame 15 can move in the optical axis direction, but cannot rotate about the optical axis.

Further, a top 8 is fixed to the inner peripheral portion of the large-diameter portion 4b of the fixed barrel 4 with a small screw 9, and the top 8 is provided at a central portion of the manual ring 3. Since the manual ring 3 is fitted in the groove 3b, the manual ring 3 can rotate about the optical axis, but cannot move in the optical axis direction.

A zoom ring 16 is held on the outer peripheral portion of the large diameter portion 4b of the fixed barrel 4 so as to be rotatable about the optical axis within a predetermined angle range. Since the interlocking lever 17 fixed to the zoom ring 16 with the machine screw 18 is engaged with the engagement groove 5a of the cam ring 5, the zoom ring 16 and the cam ring 5 rotate integrally about the optical axis. To do.

A mount member 4g that engages with the camera body is arranged at the right end of the fixed barrel 4, and a diaphragm ring 19 is arranged at the outer periphery of the right end.

A cam follower 6 is fixed to an outer peripheral portion of the cam ring 5 by a nut 6c, and its tip is fitted into a zooming cam groove 2b provided in a central portion of the first lens group moving frame 2. There is.

Further, a key 11 is fixed to the central outer peripheral portion of the cam ring 5 with machine screws 12. Since the key 11 is engaged with the circumferential groove 4e having a predetermined angle provided in the central portion of the small diameter portion 4a of the fixed barrel 4, the cam ring 5 can rotate around the optical axis. However, it cannot move in the optical axis direction.

A cam groove 5 b for the second lens group is provided on the right side of the cam ring 5, and the cam groove 5 b is planted on the outer peripheral portion of the second lens group moving frame 15. The zoom pin 13 and the central portion of the collar 14 are engaged with each other.

The cam follower 6 includes a zoom pin 6d fixed to the cam ring 5 with a nut 6c, a collar 6a, and a lid 6b. The collar 6a is made of an elastic member such as synthetic resin.

The linear guide pin 7 is composed of a pin 7a and a collar 7b. The straight-moving guide inner pin 7 is fitted in a guide groove 2c provided in the central portion of the first lens group moving frame 2 and parallel to the optical axis, whereby the first lens group moving frame 2 moves in the optical axis direction. Can move, but cannot rotate about the optical axis.

The top 8 is a member fixed to the inner peripheral portion of the large diameter portion 4b of the fixed barrel 4 with a small screw 9. Since the top 8 is fitted in the circumferential groove 3b of the manual ring 3, the manual ring 3 is held so as to be rotatable about the optical axis.

The rubber ring 10 is a ring fitted to the outer peripheral portion of the manual ring 3, and is for preventing slippage when the manual ring 3 is operated.

The key 11 is a member fixed to the outer peripheral portion of the center of the cam ring 5 with machine screws 12. Since the key 11 is engaged with the circumferential groove 4e having a predetermined angle provided in the central portion of the small diameter portion 4a of the fixed barrel 4, the cam ring 5 is rotatable about the optical axis. However, it does not move in the optical axis direction.

Reference numeral 13 is a zoom pin for the second group lens, 14 is a collar, 15 is a second group lens moving frame holding the second group lenses L3, L4 and L5 on the inner peripheral portion, and 16 is a zoom lens. A mulling, 17 is a connecting lever, 18 is a small screw, and 19 is a diaphragm ring.

Next, the cam groove for zooming will be described with reference to FIG. In FIG. 3, the horizontal axis indicates the distance in the optical axis direction of the lens barrel, and the right side in the figure is the camera body side. The vertical axis indicates the zooming state, W indicates the wide side, M indicates the middle side, and T indicates the tele side. A curve c shows a cam diagram for the first lens group, and a straight line d shows a cam diagram for the second lens group.

As shown in FIG. 3, the cam groove for the second group lens is linearly provided from the camera body side toward the front end direction of the lens barrel. The camera body side is the wide side and the lens barrel tip direction is the tele side.

The cam groove for the first lens group is provided in the first lens group moving frame 2. Therefore, this cam groove is provided continuously from the camera body side to the lens barrel tip direction from the wide side to the middle position, and from the lens barrel tip direction to the camera body side from the middle position to the tele side. There is.

The distance between the wall portion 2e that is bent in the optical axis direction of the first lens group moving frame 2 and the left end 5c of the cam ring 5 is such that when the focal length is in the middle position, the first lens group is the camera body. It is set wider than the amount L moved to the side by a minute amount α. That is, the distance between the wall portion 2e and the left end 5c of the cam ring 5 is L + α, which is a feature of this embodiment. The distance between the wall portion 2e of the conventional lens barrel and the left end 5c of the cam ring 5 is set to be larger than L + α so as not to abut each other.

The operation of the zoom lens barrel configured as described above will be described below. However, only the zooming part related to the present invention will be described.

When the zoom ring 16 is rotated, the interlocking lever 17 fixed to the zoom ring 16 by the machine screw 18 is engaged with the engaging groove 5a of the cam ring 5, so that the cam ring 5 is also centered on the optical axis. To rotate integrally.

When the cam ring 5 rotates, the second group lens cam groove 5b provided in the cam ring 5, the guide groove 4f provided in the fixed barrel 4 parallel to the optical axis, and the second group lens movement. By the action of the zoom pin 13 planted on the outer peripheral portion of the frame 15 and the collar 14, the second group lens is moved along the optical axis by a predetermined amount for zooming.

At the same time, when the cam ring 5 rotates, the zooming cam groove 2b provided in the central portion of the first group lens moving frame 2, the zoom pin 6d fixed to the cam ring 5 by the nut 6c, the collar 6a, and the lid. By the action of the cam follower 6 composed of 6b and the linear guide pin 7 fitted in the guide groove 2c provided in the central portion of the first lens group moving frame 2 and parallel to the optical axis, The group lens is also moved along the optical axis by a predetermined amount as shown in FIG. 1 to perform zooming.

However, when the focal length is at the middle position, that is, when the first lens group is closest to the camera body side, as shown in FIG. 3, the tangent line of the cam groove for the first lens group is the optical line. It is perpendicular to the axis. In this state, when a strong shock is given from the direction of arrow A shown in FIG. 2, the first group lens is passed through the female helicoid 1b of the first group lens holding frame 1 and the male helicoid 2a of the first group lens moving frame 2. The shock is directly transmitted to the moving frame 2. Therefore, the cam follower 6 composed of the zoom pin 6d fixed to the cam ring 5 by the nut 6c, the color 6a, and the lid 6b may be shocked, and the zoom pin 6d may be bent by the shock or the collar in the conventional structure. The zoom operation could not be performed smoothly due to the 6a being shaken or damaged.

Therefore, in this embodiment, as described above, the distance between the wall portion 2e and the left end 5c of the cam ring 5 is L + α, and the value of this α is the elastic limit of the collar 6a composed of the elastic member. The following values are used. As a result, even if a shock is applied, the collar 6a only elastically deforms.

Moreover, when a deformation exceeding the value of α occurs, the left end 5c of the cam ring 5 receives a shock, so that the cam follower 6 is not unnecessarily large shocked. .. Therefore, the zoom pin 6d will not be bent or damaged by a shock and will not hinder the zoom operation. Since the left end 5c of the cam ring 5 is arranged over the entire circumference of the lens barrel, it is possible to maintain sufficient strength against a large shock. In the conventional lens barrel, the distance between the wall portion 2e and the left end 5c of the cam ring 5 is larger than that of L + α, so that it can function as a stopper even if a shock is applied from the tip of the lens barrel. There was no.

Even when the lens barrel is moved back, the first lens group moving frame 2 and the cam ring 5 move together in the optical axis direction. It can be determined only by the relationship between the moving frame 2 and the cam ring 5. Therefore, the minute amount α can be easily secured by considering the precision of the machining of the first group lens moving frame 2 and the cam ring 5.

The minute amount α merely secures a clearance for normal zooming, and does not hinder the zooming operation at all.

[0042]

[Effect of the device]

 As described above in detail, according to the present invention, even if a strong shock is applied to the tip of the lens barrel, the drive ring serves as a stopper of the moving member when the shock exceeds a predetermined amount. Therefore, the cam followers will not be shocked unnecessarily. Therefore, the zoom pin or the like will not be bent or damaged due to shock, and the zoom operation cannot be smoothly performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a movement during zooming of an optical system of an embodiment of a zoom lens barrel according to the present invention.

FIG. 2 is a cross-sectional view showing a zoom lens barrel according to an embodiment, in which an upper side shows a state in which a focal length is wide and a lower side has a middle focal length.

FIG. 3 is a diagram showing a cam groove for zooming of the zoom lens barrel according to the embodiment.

[Explanation of symbols]

 L1, L2 First group lens L3, L4, L5 Second group lens 1 First group lens holding frame 1b Female helicoid 1c Protrusion 2 First group moving frame 2a Male helicoid 2b Zooming cam groove 3 Manual ring 3a Guide groove 4 Fixed barrel 5 Cam ring 6 cam follower 6d zoom pin 6a color 6b lid 7 straight guide pin 7a pin 7b color 8 frame 9 machine screw 10 rubber ring 11 key 12 machine screw 13 zoom pin for second group lens 14 color 15 second group lens moving frame 16 zoom ring 17 Connection lever 18 Machine screw 19 Aperture ring

Claims (1)

[Scope of utility model registration request] 1. A zoom lens barrel, the overall length of which changes when the first lens group reciprocates in the optical axis direction during zooming, wherein a moving member that engages with a holding member that holds the first lens group, and an optical member. The distance in the optical axis direction from the drive ring that rotates about the axis and drives the holding member via the moving member,
When the first lens group comes closest to the camera body, there is a minute gap during normal zooming, and when the first lens group receives a force from the direction of the tip of the first lens group, they come into contact with each other to serve as a stopper. A zoom lens barrel characterized by being set.