JPH0248615A - Lens barrel for close-up photographing - Google Patents

Abstract

PURPOSE:To improve the position accuracy of a moving lens group by providing a moving means for moving a variable power lens group from a first position to a second position by a cam means during an expansion operation in one direction of an intermediate device, and thereafter, on the contrary, returning it on a locus of a cam from a second position to a first position. CONSTITUTION:A front group cam cylinder 3 and a rear group cam cylinder 5 can be rotated mutually as one body through a key member 25. Accordingly, when both the c am cylinders 3, 5 rotate forward and backward against a fixed lens barrel 4, a first lens group L1 and a fourth lens group L4 move in the direction separated from a second lens group L2 and a third lens group L3 being immobile, respectively along an optical axis, or move in the direction for approaching the latter. In accordance therewith, a lens group array in varied steplessly from an array of a short focus state to an array of a long focus state, and furthermore, to an array of a short focus state. By such a cam means, an angle theta made by tangents of cam grooves 15, 22 and linear grooves 12, 21 can taken comparatively large, therefore, a pin moves smoothly and the position accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens barrel that is attached to an intermediate device for close-up photography and is used when photographing a subject in close-up or enlarged form using a camera.

(Prior art) Conventionally, when performing so-called close-up photography with a magnification of more than 0.2x and up to about 10x, an intermediate device has been used to widen the distance between the camera and the m-shade lens (lens barrel). is used. Generally, the intermediate device used is a bellows-type feeding device that telescopically connects the camera mounting part and the photographic lens mounting part with a light-shielding bellows, or a so-called intermediate tube that is interposed between the camera and the photographic lens. has been done. The photographic magnification is determined by the amount of extension of the photographic lens, so in the case of the former bellows type, by adjusting the amount of expansion and contraction of the bellows, and in the case of the latter tube, by changing the tube length, the desired photographic magnification can be achieved. was obtained, and filming is underway.

FIGS. 4(a), 4(b), and 4(C) are diagrams showing a correlation model between the projection amount d of the photographing lens and the photographing magnification β.

L is focal path 1! llf photographing lens, F is the film surface as the imaging plane, Yo is the subject, Y is the image formed, a is the subject distance (photographing lens L → subject Y0 open circuit 111), b is the distance till (photographing lens LM focusing) Image plane F open circuit ll! I),
L is the photographing distance (subject Y; H is the imaging plane F open path Il).

(a) In the figure, the amount of extension of the photographing lens L is d = 0, that is, the focus of the lens L is located on the imaging plane F, and the photographing magnification β = 1/ω.
The case is shown below. Figures (b) and (C) each show the state in which the lens L is extended, and the figure (b) shows the imaging magnification β.
The figure is 1x, and (C) is 2x.

Therefore, the photographing magnification β, the photographing distance 1lIIL, and the subject distance 111.
a is expressed by the following relational expressions.

β=Y/Y0=b/a=d/f...(1)11=f
(1 + β) 2/β ... (2) The graph in Figure 1 is a solution of the above equation (2) with the shooting distance 1lIIL as a constant value, and the lens extension amount d (when the shooting magnification is 1/ω) If you change the focal length @f of the photographing lens from increasing to decreasing in conjunction with the increase in the distance between the photographing lens and the film (focal plane), you can shoot without changing the photographing distance @l. The magnification β can be monotonically increased.

Since the above-mentioned optical type (2) is an image forming type, the photographing focus will not shift due to a change in the feeding md.

FIG. 2 is an optical system model diagram of an example of a variable focal length photographing lens as a photographing lens.

L2, L3, and L4 are lens groups each composed of one or more lenses, and D is an aperture.

The focal length is changed, that is, the magnification is changed by moving the second lens group L2, the third lens group L3, the fourth lens group L4, and the aperture D, respectively.

The lens position states of (a), (b) and (c) in Figure 2 are respectively focal lengths f, -f2 and -f2 on the graph in Figure 1 (1).
The position state at f3 is shown. (a) and (c) have an optically conjugate arrangement, and f+ = f3. t/
Due to the relationship β1=β3, β2=×1. In other words, the second lens group L2, the third lens group L3, and the diaphragm D move linearly as a unit. The lens group and the fourth lens group L4 move completely symmetrically with respect to the second lens group L2, the third lens group L3, and the aperture D, so that the magnification is the same (b
), the distance between each lens is the closest. Furthermore, the relative movement of the lens group and the fourth lens group with respect to the second lens group L2, third lens group L3, and aperture D on the optical axis is the movement from photographing magnification β1 to β2 (equal magnification) and from β3 to β2 (equal magnification). It is configured so that the movements up to β2 (same magnification) are equal. In other words, the second lens group L2, the third lens group L3,
The lens group L1 and the fourth lens group L4 for the aperture D
The position at each magnification is shown in FIG. Furthermore, at each magnification and at any imaging magnification between them, the distance between the subject and the intended imaging plane is always constant, and once focused, there is no need to focus again even if the magnification is changed.

In order to perform the movement of the optical system as shown in Figs. 2 and 3 above in close-up photography, the movement of the second lens group L2, third lens group L3, and aperture D is performed by a bellows (intermediate device). The movement of the lens group L1 and the fourth lens group L4 is performed by operating a cam mechanism fixed to the movable side of the bellows, and the movement of the bellows and the movement of the cam mechanism are combined to produce the movement shown in Figure 2. Luns Group LI, and 4th
The movement of lens group L4 is realized.

A developed view of a general cam mechanism at this time is shown in FIG.

Reference numeral 201 denotes an immovable fixed portion, which has a straight groove 201a extending along the optical axis 0-0.

Reference numeral 202 is a cam cylinder which is freely supported with respect to the fixed part 201 only in the rotational direction. The cam cylinder 202 has a cam cylinder 202a.
is formed. Reference numeral 203 denotes a bin of the movable lens group barrel, and the movement of this bin 203 is the same as that of the variable power lens group (tz and L4) held in the movable lens group barrel.

The pin 203 passes through the straight groove 201a of the fixed portion 201 and fits into the cam groove 202a of the cam cylinder 202. When the cam cylinder 202 is rotated in the direction of arrow B in this state, the bin 203 moves in the direction of arrow C and then in the direction of arrow E. Therefore, the zoom lens group also moves in the same way as the bin 203.

As shown in Fig. 3, the cam mechanism as described above is used.
The first run group 1. Movement of the fourth lens group L4 is realized.

(Problem to be Solved by the Invention) However, in the cam mechanism configuration as shown in the example in FIG. There is a tendency for the length of the cam groove 202a in the circumferential direction to increase.

- Numerically, it is necessary to arrange multiple cam mechanisms,
Increasing L causes problems in terms of space. In addition, if the length of the cam groove in the circumferential direction is made smaller, the angle θ between the tangential direction of the cam and the linear groove becomes smaller, which impairs the movement of the pin and furthermore impairs the positioning accuracy of the pin, resulting in the position of the moving lens group. Since the accuracy also deteriorates, a problem arises in that optical performance deteriorates.

The present invention also uses a cam mechanism to move a variable magnification lens group, and it is an object of the present invention to provide a lens barrel for close-up photography of this type that eliminates the problems described in F.

(Means for Solving the Problems) (1) The present invention is a lens barrel for close-up photography that is attached to an extendable intermediate device of a close-up photography device, and that moves in the optical axis direction for variable magnification photography. two or more groups of variable power lenses; cam means that operates in conjunction with the expansion/contraction operation of the intermediate device to move the variable power lens group to a variable power position according to the amount of expansion/contraction of the intermediate device; During the one-way expansion and contraction operation of the intermediate device, the variable power lens group is moved from the first position to the second position by the cam of the cam means, and then conversely from the second position to the first position. A lens barrel for close-up photography characterized by comprising a moving means for returning the cam on a trajectory in the direction of the position.

(Function) That is, as mentioned above, during the one-way expansion and contraction operation of the intermediate device, the variable power lens group is moved from the first position to the second position by the cam of the cam stage.
After moving to the first position, conversely, move from the second position to the first position.
By providing a moving means for returning the trajectory of the cam in the direction of the position, the cam groove can be easily arranged in the cam means (cam cylinder), and the angle between the tangent of the cam groove and the straight groove is relatively small. It can be taken in large quantities. This has the effect of smooth pin movement and good positional accuracy.

(Example) Fig. 5 is a longitudinal sectional side view of a close-up photographing device equipped with a lens barrel according to the present invention, and A is a general view of a variable focal length photographing lens (hereinafter abbreviated as photographing lens) as a lens barrel. The symbol B is a general symbol of the intermediate device (bellows), and C is the camera. Regarding camera C, its outline is indicated by a two-dot chain line and the detailed structure is omitted.

■, Configuration of shooting lens A, vertical sectional side view in Figure 5, developed plan view of main parts in Figure 6, Figure 7
In the plan view shown in the figure and the side view shown in Fig. 8, 1 is an exterior ring;
3 is a guide cylinder that is fitted concentrically into the outer ring with an annular gap and is integrally screwed together with the outer ring; 3 is a 01 group cam cylinder that is fitted concentrically into this guide cylinder; It can be freely rotated forward and backward around the optical axis inside. Reference numeral 4 denotes a fixed lens barrel which is integrally screwed to the rear end of the guide tube 2 concentrically with the guide tube and protrudes rearward from the rear end of the exterior ring 1;
is a rear group cam barrel that is fitted concentrically to the fixed lens barrel, and is rotatable forward and backward around the optical axis outside the fixed lens barrel. Reference numeral 6 designates an annular mount that is integrally attached and fixed to the distal end flange portion of the fixed lens barrel 4 at the rear end position of the exterior ring 1, and is for attachment to an intermediate device B, which will be described later. Therefore, the four members, the outer ring 1, the guide cylinder 2, the fixed m cylinder 4, and the mount 6, are integral with each other.

Reference numeral 7 denotes a lens barrel holding the lens group L1, which is fitted inside the front group cam barrel 3 at the tip end side thereof and concentrically with the cam barrel. Reference numeral 8 denotes a second lens group barrel holding the second lens group L2, which is integrally mounted and supported at the tip of the fixed lens barrel 4, and is mounted inside the cam barrel 3 on the rear end side of the front group cam barrel 3. It is located concentrically with the cam cylinder.

Reference numeral 9 denotes a third lens group barrel that is integrally molded within the fixed lens barrel on the distal end side of the fixed lens barrel 4, concentrically with the lens barrel, and holds the third lens group L3. ing. 10
A fourth lens group lens barrel is fitted inside the rear end side of the fixed m-cylinder 4, and holds the fourth lens group L4. 11 is the second
and an aperture unit that is integrally mounted and supported on the fixed lens barrel 4 side in the open position with the third lens group barrels 8 and 9, and includes a stepping motor lla;
The aperture D is driven by la.

The cylindrical surface of the guide tube 2 has two stripes parallel to the optical axis (in the direction of the generatrix of the cylindrical surface) at two positions facing each other at approximately 180 degrees around the periphery of the cylinder, as shown in the developed plan view of the main part in Fig. 6. It is provided with rectilinear grooves 12 and 12, and first and second two parallel circumferential grooves 13 and 14 in the circumferential direction of the cylinder, which is a direction perpendicular to the straight grooves. Also, on the cylindrical surface of the front group cam 'rt43 fitted inside the guide cylinder 2, approximately 1 part of the cylindrical circumference is formed.
Edge calcam grooves 15 are provided at two positions facing each other at 80 degrees. Then, pin shafts 16 are implanted into the lens barrel 7 fitted inside the front group cam barrel 3 at two positions approximately 180° opposite each other around the barrel circumference, and these pin shafts are connected to the front group cam barrel 7, respectively. It is penetratingly engaged with the intersection of both the edge cam slot 15 of the cylinder 3 and the linear groove 12 of the guide cylinder 2. Therefore, the first lens group lens barrel 7, that is, the first lens group, advances in the optical axis direction within the front group cam barrel 3 by rotating the front group cam barrel 3 forward and backward around the optical axis with respect to the guide barrel 2.・Move backwards. Reference numeral 17 denotes a front group biasing spring stretched between the tip of the exterior ring 1 and the lens group barrel 7, which constantly pulls the lens barrel 7 in the forward direction within the front lens group cam barrel 3. It is energizing.

Reference numeral 18 denotes a protruding member integrally provided on the outer surface of the front group cam cylinder 3, the tip of which is connected to the first circumferential groove hole 13 of the guide cylinder 2.
is made to penetrate and protrude to the outer surface side of the guide tube 2. 19
is a bottle installed on the outer surface of the guide tube 2, and this bottle 19
A cam cylinder drive spring 20 is stretched between the protruding member 18 and the protruding member 18. This cam barrel drive spring 20 constantly rotates the front group cam barrel 3 clockwise (forward rotation direction) around the optical axis within the guide barrel 2 when viewing the shadow lens A from the front (first lens group, side). It is energizing.

On the other hand, on the cylinder surface of the fixed lens barrel 4, as shown in the developed plan view of the main part in FIG. Linear straight grooves 21 and 21
It is equipped with. In addition, the rear group cam cylinder 5 externally fitted onto the fixed cylinder 4 is provided with edge cam slots 22 at two positions approximately 180° opposite each other around the cylinder periphery. Then, pin shafts 23 and 23 are implanted in the fourth lens group barrel 10 fitted inside the fixed barrel 4 at two positions approximately 180° opposite to each other around the barrel circumference.
These pin shafts are respectively penetrated and engaged with the intersection portions of the linear groove 21 of the fixed lens barrel 4 and the edge cam groove 22 of the rear group cam barrel 5.

Therefore, the fourth lens group barrel 10, that is, the fourth lens group,
By rotating the rear group cam barrel 5 forward and backward around the optical axis with respect to the fixed lens barrel 4, it moves backward and forward in the optical axis direction within the fixed lens barrel 4. 24 is a rear group biasing spring stretched between the rear end of the fixed lens barrel 4 and the fourth lens group barrel 10; is constantly under tension.

A key member 25 has one end fixed to the outer surface of the front end side of the rear group cam cylinder 5 and the other end fitted into a notch groove 26 formed in the rear end flange of the front group cam cylinder 3. Therefore, rotational force is transmitted between the rear group cam cylinder 5 and the front group cam cylinder 3 through this key member 25, and when one rotates in the forward and reverse directions, the other also rotates in the forward and reverse directions. This is a pawl that is integrally provided on the outer surface of the group cam cylinder 5 and is interlocked with an intermediate device B, which will be described later.

Reference numeral 28 denotes an electric signal bin assembly provided on the mounting mount 6.

A circuit unit 29 is fixed to the outer surface of the guide tube in a gap space between the outer ring 1 and the guide tube 2, and is connected to the aperture unit 11 and the electric signal bin assembly 28 via lead wires (not shown). are connected to each other.

30 is housed in the gap space between the exterior ring l and the guide tube 2,
It is a magnification display plate in the shape of an arc plate concentric with the optical axis, and a downwardly bent leg portion 30a integral with the display plate is passed through the second circumferential groove hole 14 of the guide tube 2 and fitted into the guide tube 2. It is supported by the front group cam cylinder 3 by being integrally fixed to the outer surface of the front group cam cylinder 3. Therefore, when the front group cam barrel 3 is rotated in the forward and reverse directions, the magnification display plate 30 rotates in the forward and reverse directions around the optical axis together with the cam barrel.

31 is a window hole provided on the outer surface of the exterior ring 1; 31a is a transparent cover member for dustproofing that covers this window hole; is visible.

Reference numeral 32 (FIGS. 7 and 8) is a fixed index attached to the outer surface of the rear end side of the exterior ring 1, and is an alignment mark when attaching the photographing lens A to an intermediate device B, which will be described later.

The first to fourth lens groups L1 to L4 and the aperture D are the second lens groups described above.
The first to fourth lens groups shown in Figure 3, %L4. and aperture D, and when the rear group cam barrel 5 is rotated forward and backward with respect to the fixed lens barrel 4, the lens group lens barrel 7, that is, the fourth lens group L1, and the fourth lens group The lens group barrel 10, that is, the fourth lens group L4, moves in a direction away from the second lens group L2, which is immobile along the optical axis, and moves away from the third lens group L3 (the lens group L1 moves forward along the optical axis). , the fourth lens group L4 moves backward), or the second lens group L2
- Moves in the direction approaching the third lens group L3 (the lens group L1 moves backward along the optical axis, and the fourth lens group L4 moves forward, on the contrary), and the lens group arrangement is as shown in Figure 2 (a). (C)
, the array in the short focus state (magnification β1 or β3) in FIGS. 3(a) and 3(C), or the array in the long focus state (magnification β2 ( The array status changes steplessly to the same size (equal size).

In the vertical sectional side view of the device in FIG.
The upper half from the optical axis with -0 as the border shows the mutual arrangement in the short focus state with magnification β1 or β3, and the lower half shows the magnification β2 (same magnification).
The mutual arrangement of the two images in the long focus state is shown.

■ Structure of Intermediate Device B In the longitudinal sectional side view of FIG. 5, the side view of FIG. 9, and the partially cutaway front view of FIG. A rack 51 is fixedly provided along the support member (hereinafter referred to as the first support member) for mounting the photographic lens.
The guide rail member 50 is mounted on the guide rail member 50 so that the base side engages with the rail member in a dovetail groove so that it can smoothly and stably move forward and backward along the length of the rail member. It is. Reference numeral 52 denotes a support member (hereinafter referred to as a second support member) for mounting the camera, and the first support member 5
On the rear side of 1, the guide rail member 50 is also mounted on the guide rail member 50 so that the base side engages with the rail member in a dovetail groove so that it can smoothly and stably slide forward and backward along the length of the rail member. .

Reference numeral 53 denotes a drive knob shaft disposed on the base side of the first support member 51 so as to pass through the member in the left-right direction and be freely rotatably supported;
54, 54 are knobs fixed to both left and right ends of the knob shaft;
Reference numerals 5 and 56 denote a pinion gear and a drive gear respectively fixed to the middle of the knob shaft. Therefore, when the knob 54 is rotated in the forward and reverse directions, the pinion gear 55 and the rack 50a on the side of the guide rail member 50 are engaged with each other, so that the first member 51
slides forward and backward along the rail member 50.

Similarly, for the second support member 52, a drive knob shaft 57 is disposed through the base side of the second support member 52 so as to freely rotate and bear the shaft, and a rack 50a on the side of the guide rail member 50 is disposed in the middle of the drive knob shaft 57. The second member 52 is provided with mesh gears 59, and is moved forward and backward along the rail member 50 by rotating the knobs 58 fixed to both left and right ends of the knob shaft 57 in forward and reverse directions. .

In the first member 51, 60 (Fig. 10) is an opening for inserting a photographic lens, 61 is an annular mount fixed concentrically with the opening 60 on the front side of the member 51, and 62 and 63 (Fig. 5) are the members. A pair of front and rear interlocking rings 64 are rotatably assembled concentrically with the opening 60 on the back side of the member 51, and 64 are the first and second interlocking ring receivers, which are fixed to the member 51. The first and second interlocking rings 62 and 6
3 is rotatably held. 62a and 63a are first and second interlocking claws provided inwardly on a part of the inner periphery of the first and second interlocking rings 62 and 63, and 62b and 63b are the first and second interlocking claws, respectively. These are first and second interlocking gears that are integrally provided on each side of the interlocking rings 62 and 63, concentrically with the rings. A drive gear 5 integrated with the drive knob shaft 53
6 and the second interlocking gear 63b are connected to the interlocking gear train 0.
We will contact you via 1 to G7. Gears G1 and G2, G3 and G4, and G5 and G6 are coaxial, integrally rotating two-stage gears. Also, the final gear G7 of the above gear train (
The second interlocking gear 63b and the first interlocking gear 62b are engaged with each other via a differential gear G8 (FIG. 10).

Therefore, as described above, the photographing lens is attached when the first support member 51, which is a support member, is slid forward and backward along the guide rail member 50 by rotating the knob 54 in the forward and reverse directions. The forward or reverse rotational force of the drive gear 56 is transmitted to the second interlocking gear 63b via the gear trains 61 to G7, and further transmitted to the first interlocking gear 62b via the differential gear G8. The first and second interlocking rings 62 and 63 are driven in forward and reverse directions with the same rotation angle but opposite rotation directions.

Reference numeral 65 (FIG. 5) is an electric signal bottle assembly in which the tip of the bottle is always urged to protrude by an elastic splash plate member 65a on a part of the outer surface of the annular mount 61, and the first member 5
When the photographing lens A is properly attached to the photographing lens mounting opening 60 of the first photographic lens A, the electric signal assemblies 28 of the eight photographing lenses are placed in the two assemblies 65 and 65 so that the electric signal assemblies 28 of the eight photographing lenses are properly faced to each other. 28 corresponding bottles come into pressure contact with each other, and both assemblies 65 and 28 are in electrical communication with each other.

Reference numeral 66 (FIG. 10) is a fixed index attached to the outer surface of the uppermost portion of the annular mount 61, and is a mark for alignment with the fixed index 32 (FIGS. 7 and 8) attached to the eight photographic lenses.

The camera is attached to the second support member 52 as a support member, with reference numeral 67 an opening for attaching the camera, and reference numeral 68 an annular mount for attaching the camera fixed concentrically with the opening 67 on the back side of the member 52.

69 is interposed between the first support member 51 and the second member 52, with the front end fixed to the first support member 51 and the rear end fixed to the second support member 52. It is a bellows serving as a dark housing part with a telescopic structure in which the photographing lens fitting opening 60 on the side and the camera mounting opening 67 on the second support member 52 side are communicated in the optical axis direction.

Reference numeral 70 denotes an electrical signal bin assembly mounted on the annular mount 68 for mounting the camera.

By engaging a facing mount (not shown) on the camera C side with the mount 68, the camera C is firmly mounted and supported on the second support member 52.

When the camera C is properly mounted and supported on the second support member 52 via the mount 68, the mount 68
An electrical signal bin assembly (not shown) on the camera C side comes into corresponding contact with the electrical signal bin assembly 70 on the side, and the two assemblies are in electrical communication with each other.

Electrical signal bin assembly 70 on the second support member 52 side
The assembly 65 on the first support member 51 side is electrically connected to each other by a lead wire (not shown). Therefore, when the photographic lens A is properly mounted and supported on the first support member 51 of the intermediate device B, and the camera C is properly attached and supported on the second support member 52, the electric circuit on the camera C side and the electric circuit of the eight photographic lenses are connected. They are in contact with each other.

The bellows 69 moves the first support member 51 and/or the second support member 52 forward and backward along the guide rail member 50 by forward and reverse rotation operations of the knobs 54 and 58, thereby increasing and decreasing the mutual spacing between the members 51 and 52. When changed, the aperture 60 for fitting the photographing lens on the first support member 51 side and the aperture 67 for attaching the camera on the second support member 52 side expand and contract depending on the size of the mutual spacing, and the aperture 67 for attaching the camera on the second support member 52 side extends and contracts in accordance with the size of the mutual interval. We are always in constant communication via road.

(2) Interlocking of intermediate device B and photographic lens A The photographing lens of intermediate device B (hereinafter referred to as bellows) is attached to the first support member 51 which is a support member. Insert the rear group cam barrel 5 portion of the photographing lens A into the mounting opening 60, and attach the photographing lens A so that the fixed index 32 on the photographing lens A side corresponds to the fixed index 66 on the first support member 51 side. The mount 6 on the photographic lens A side is brought into contact with the mount 61 on the first support member 51 side by adjusting the rotation angle posture of the photographic lens A.
sufficiently rotate clockwise until further rotation is prevented by a stopper (not shown). (In this example device, approximately 6
(0° rotation operation) As a result, the photographing lens A is stably mounted and supported on the first support member 51 by the mutual engagement of the mounts 6 and 61. In the normal mounting state, the photographing lens A is in a rotating angle position in which the magnification display window 31 portion of the outer ring 1 faces upward, and the electric signal bin assembly 28 is normally attached to the same assembly 65 on the first support member 51 side. They face each other face-to-face and are electrically connected to each other.

When the photographing lens A is inserted into the opening 60 of the first support member 51 and rotated in the manner described above in order to attach the photographing lens to the first support member 51, the rear group cam 85 of the photographic lens A is rotated. The interlocking pawl 27 that protrudes from the outside comes into contact with and is locked with the second interlocking pawl 63a on the first support member 51 side. For this purpose, the rear group cam cylinder 5, this cam cylinder and the key member 2
The rotation of the front group cam cylinder 3, which is integral with the outer ring 5, is stopped at that point. The fixed lens barrel 4 that is fixedly connected, the tip flange of this fixed lens barrel, and the mount 6 that is integrally fixed to the joint are further rotated until further rotation is prevented by a stopper portion (not shown). Rotate. As a result, the cam cylinder drive spring 20 stretched between the protruding member 18 of the front group cam cylinder 3 and the planting pin 19 of the guide cylinder 2 is in a stretched state. The developed plan view of the main part of FIG. 6 shows the spring 20 in a stretched state.

That is, after the photographic lens A is attached to the first support member 51 of the bellows B, the interlocking pawl 27 of the rear group cam barrel 5 of the photographic lens A is moved toward the first support member 51 by the reaction force of the spring 20 stretched as described above. The second interlocking pawl 63a is always pressed and kept in contact with the second interlocking pawl 63a without play.

With the photographic lens A attached to the first support member 51 of the bellows B as described above, and the camera C attached to the second support member 52, the first support member 51 and the knob 54 are rotated in the forward and reverse directions. When the guide rail member 50 is moved forward and backward, the forward and reverse rotation forces of the drive gear 56 are transmitted to the second interlocking gear 6 via gear trains 01 to G7.
3b and has a second interlocking pawl 63a.
The interlocking ring 63 is rotated forward and backward. The interlocking gear 62b of the writer 1 rotates in the normal direction via the gear G7 and the differential gear G8.
The first interlocking ring 62 receives a reversing force and is rotated forward and reverse in a relationship such that the rotation angle is equal to that of the second interlocking gear 63b but the rotation direction is opposite, and the first interlocking ring 62 has a first interlocking pawl 62a.
is rotated forward and reverse. That is, a second interlocking ring 63 having a second interlocking pawl 63a, and a first interlocking pawl 62a.
The first interlocking ring 62 having a
In conjunction with the forward and backward movement operations along the guide rail member 50, the motor rotates forward and backward in the above relationship.

And the second interlocking claw 63a of the second interlocking ring 63
, or the first interlocking claw 62a of the first interlocking ring 62, the interlocking claw 27 on the photographing lens A side is always in engagement contact with the reaction force of the spring 20 in the above-mentioned stretched state,
Therefore, the second or first interlocking ring 6 is interlocked with the forward/backward movement operation of the first support member 51 along the guide rail member 50.
The rear group cam M5 of the photographing lens A is fixed in conjunction with the forward and reverse rotations of 3 and 62! The cylinder 4 is rotated forward and reverse around the outside. Further, the front group cam cylinder 3, which is integrated with the rear group cam cylinder 5 via the key member 25, is also rotated forward and reverse around the inner circumference of the guide cylinder 2 together with the rear group cam cylinder 5. In conjunction with the forward and reverse rotations of the front group and rear group cam barrels 3 and 5, as described above, the lens group lens barrel 7, that is, the lens group LI%, and the fourth lens group lens barrel 10, that is, the fourth lens. Group L4 is along the optical axis,
The second lens group L2, which is stationary, is driven to move away from or toward the third lens group L3, respectively, and is driven to move away from or approach the second lens group L2, D, and third lens group L3, respectively.
) in the short focus state (alignment state with magnification β or β3), or the lens arrangement in the long focus state (magnification β2 (equal magnification)) in Figures 2 (b) and 3 (b). The expression changes.

■Specifically, when changing the magnification from the low magnification side (imaging magnification β1) to the high magnification side in FIG. is rotated in the normal direction to move it forward along the guide rail member 50.

In the low magnification state where the first support member 51 is closest to the second support member 52 located on the rear end side of the guide rail member 50 as shown in FIG.
The interlocking mechanism is the interlocking pawl 2 on the lens A side as shown in Figure 11.
7 and the second interlocking pawl 63a on the bellows portion side are in contact with each other.

■ From this state, rotate the knob 54 in the forward direction to move the first support member 51 of the bellows B forward to the approximately midpoint position of the rail member 50 as shown by the two-dot chain line in FIG. It is designed to be β2. At this time, the interlocking mechanism between lens A and bellows B is as shown in FIG. (cannot be seen because they overlap) are in contact with each other.

■Furthermore, rotate the knob 54 in the normal direction to move the first support member 51 of the bellows B to the rail member 5 as shown by the three-dot chain line in FIG.
When the plane is moved to a position closer to the tip of 0, the imaging magnification is
From the same magnification β2 to the higher magnification β3, at this time the interlocking mechanism between lens A and bellows B becomes as shown in Fig. 13.
The interlocking claw 27 on the lens A side is in contact with the first interlocking claw 62a on the bellows side.

By the above operation ■→■→■, the rear group cam WJ of the photographic lens A is
5 and front group cam cylinder 3 are interlocking rings 63 and 6 of Heroes B.
2, from low magnification β1 to equal magnification β2, equal magnification β
The rotation direction is reversed from 2 to high magnification β3. The movements of each lens group ~L4 and diaphragm D are shown in FIG. Also, the planned imaging plane F (film plane inside camera C)
The movements of each lens group, ~L4 and aperture D with respect to the second
The result will be as shown in the figure.

Furthermore, a front group biasing spring 17 is installed between the lens barrel 7 of the lens group 7 and the tip of the exterior ring 1, and extends in the direction of extension of the lens group tl!
Since lQ7 is biased, the biasing force assists the movement of the pin shaft 16 passing through the edge cam slot 15 of the front group cam cylinder 3 in the direction of extension of the spring 17. At the same time, since the pin shaft 16 is pressed in one direction with respect to the edge cam horizontal hole 15 by the biasing force, the positional accuracy of the pin shaft 16 can be determined with high precision.

Further, a rear group biasing spring 24 is installed between the fourth lens group mirror WUlO and the end of the fixed lens barrel 4, and extends in the extension direction of the fourth lens group 1! Since the cylinder 10 is biased, the movement of the pin shaft 23 fitted into the edge cam slot 22 of the rear group cam cylinder 5 in the direction of extension of the spring 24 is assisted. At the same time, since the position of the pin shaft 23 relative to the edge cam slot 22 is pressed in the direction by the biasing force, the positional accuracy of the pin shaft 23 is determined with high precision.

The magnification display plate 30 rotates together with the cam barrel 3 as the front group cam barrel 3 rotates in the forward and reverse directions to change the magnification by rotating the knob 54 in the forward and reverse directions. Guide rail member 5 of the first support member 51 on the moved bellows part side
The magnification value display portion corresponding to the current position on o is located in the upward facing window hole 31 provided on the outer surface of the outer ring 1, and the magnification value at the current time corresponds to the index 31b (FIG. 7). displayed accurately.

Thus, the photographing lens (lens barrel) A of this embodiment is a cam that moves the variable magnification lens group about the lens barrel for close-up photography, which is configured to change the focal length in conjunction with the amount of expansion and contraction of the intermediate device for close-up photography. By having the cam cylinders 3 and 5 as means and having a structure that allows the movement of the bottles 16 and 23 to reciprocate with respect to the cam grooves 15 and 22, as shown in Fig. 6, in comparison with the one in Fig. 14. , the intersection angle θ of the cams can be made larger, the movement of the variable power lens groups L1 and L2 becomes smoother, and the positional accuracy of the variable power lens groups is improved.

■ Attach the photographing lens A to the bellows B within the angle, and the interlocking members 63a and 62a between the bellows 8 side and the eight photographing lenses.
, 27, the rotation angles of the cam cylinders 3 and 5 could be realized.

(Effects of the Invention) As described above, during the unidirectional expansion/contraction operation of the intermediate device, after the variable power lens group is moved from the first position to the second position by the cam of the cam means, it is reversely moved. By providing a moving means for returning the trajectory of the cam from the second position to the first position, the arrangement of the cam groove in the cam means (cam cylinder) is facilitated, and the tangential line of the cam groove The angle formed by the straight groove can be relatively large. This has the effect of smooth movement of the bin and good positional accuracy.

[Brief explanation of the drawing]

Figure 1 is a principle mode graph for close-up photography, Figures 2 and 3 are optical system model diagrams of variable focal length photography lenses, and Figure 4
Figures (a), (b) and (C) are correlation model diagrams of the lens extension amount and photographic magnification, Figure 5 is a longitudinal cross-sectional side view of a close-up photographing device equipped with a photographing lens according to the present invention, and Figure 6 is a diagram of the relationship between the lens extension amount and photographing magnification. Developed plan view of the main part (cam mechanism), Figures 7 and 8 are a plan view and side view of the photographing lens, Figure 9 is a side view of the intermediate device (bellows), and Figure 10 is a partially cutaway front view. Figure, 1st
Figures 1, 12, and 13 are explanatory diagrams of the engagement relationship between the interlocking pawl on the photographing lens side and the interlocking pawl on the intermediate device side, respectively, and Fig. 14 is an exploded plan view of the main parts of a conventional cam mechanism. be. A is the photographic lens (focal length variable photographic lens), B is the intermediate device (bellows), C is the camera, L1 to L4 are the first to fourth lens groups, D is the diaphragm, and 5152 is the intermediate device for mounting the photographic lens. A supporting member (first supporting member) and a supporting member (second supporting member) for mounting the camera, 50 a guide rail member, 5
4.58 is a support member movement operation knob. Figure Figure A> Thread diagram

Claims (1)

[Claims] (1) A lens barrel for close-up photography that is attached to a telescoping intermediate device of a close-up photography device, comprising two or more variable magnification lens groups that move in the optical axis direction for variable magnification photography, and the intermediate device. cam means that operates in conjunction with the expansion/contraction operation of the intermediate device to move the magnification changing lens group to a magnification changing position according to the amount of expansion/contraction of the intermediate device; A moving means for moving the lens group from the first position to the second position by the cam of the cam means and then returning the lens group from the second position to the first position on the trajectory of the cam. A lens barrel for close-up photography, comprising: