JPH0248616A - Lens device - Google Patents

Abstract

PURPOSE:To smoothly move a pin and to improve the position accuracy by providing a transfer mechanism for bringing the pin to reciprocating movement against a cam groove of a cam means for moving a variable power lens group during an expansion operation in one direction of an intermediate device. CONSTITUTION:A rear group cam cylinder 5 and a front group cam cylinder 3 rotate forward and backward as one body because rotational force is transferred to each other through a key member 25. When a first supporting member 51 is in a low magnification state which is approaching most a second supporting member 52 positioned on the rear end part side of a guide rail 50, an interlocking claw 27 of a lens A side and a second interlocking claw 63a of a bellows B side abut on each other. When a first supporting member 51 is advanced and moved to an intermediate point position shown by a two-point chain line from said state, it becomes an unmagnification position where the interlocking claw 27 of the lens A side and the interlocking claws 63a, 62a of the bellows side abut on each other. Also, when a first supporting member 51 is advanced and moved to a position toward the tip shown by a three-point chain line, the photographing magnification becomes a high magnification state. In such a way, by interlocking with the forward turn the reverse turn of the front group and the rear group cam cylinders 3, 5, lens groups L1, L4 move in the separated direction or in the approaching direction against immobile lens groups L2, L3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens device (close-up photographing device) that uses a camera to take close-up or enlarged photographs of a subject.

(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 photographic lens (lens barrel). It is being 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 shooting magnification is determined by the amount of green exposure of the shooting 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 shooting can be achieved. Photography is being carried out after obtaining magnification.

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

is the l shadow of the focal ratio llf, F is the film plane as the imaging plane, Y is the subject, Y is the image formed, a is the subject pressure l
1l (distance fi between 4-4 subject Y0 on the photographic lens), b is distance maintenance m<photographing lens L-imaging plane F open circuit m>, tt is photographing distance (subject Y; distance between 4-4 imaging plane F) It is.

(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 = 110.
The case of 0 is shown. Figures (b) and (C) each show the state in which the lens L is extended, and the photographing magnification β in figure (b) is approximately 1x, and in figure (C) it is 2x.

The photographing magnification β, the photographing distance 2, and the subject distance a are each expressed by the following relational expressions.

β=Y/Y0=b/a=d/f...(1) It=f
(1 + β) 2/β ... (2) The graph in Figure 1 is a solution of the above equation (2) with the shooting distance @i as a constant value, and the lens extension amount d (for the shooting magnification of 110o) If the focal length f of the photographing lens is changed from increasing to decreasing in conjunction with the increase in the distance between the photographing lens and the film (focal plane), the photographing magnification β will be increased without changing the photographing distance @IL. 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 lid.

Fig. 2 is an optical system model diagram of an example of a variable focal length photographic lens as a photographic lens, and L1L2 ・L3 ・L
4 is a lens group each composed of one or more lenses, and D is an aperture. The first Luns group,
- By moving the second lens group L2, the third lens group L3, the fourth lens group L4, and the diaphragm D, the focal length is changed, that is, the magnification is changed.

The lens position states of (a), (b), and (c) in Figure 2 are the focal lengths f1 and f2 on the graph in Figure 1 (1), respectively.
- Shows the position state at f3. (a) and (c
) has an optically conjugate arrangement, f, = f3.1
/β,=β3, and β2=x1. In other words, the second lens group L2, the third lens group L3, and the diaphragm D move integrally and linearly. The lens group L1 and the fourth lens group L4 move completely symmetrically with respect to the second lens group L2, the third lens group L3, and the diaphragm D, so that the distance between each lens is the best in the same magnification state (b). It gets closer. Further, the movement of the second lens group and the fourth lens group relative to the second lens group L2, the third lens group 3, and the aperture D on the optical axis corresponds to the photographing magnification β.

The structure is such that the movement from β3 to β2 (equal magnification) is equal to the movement from β3 to β2 (equal magnification). In other words, the positions of the second lens group 2, the third lens group, the lens group 3 and the fourth lens group L4 relative to the aperture D are as 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 make the optical system move as shown in FIGS. 2 and 3 in close-up photography, the second lens group L2, the third lens group L3 . The movements of the diaphragm D and the diaphragm D are performed by a bellows (intermediate device), and the movements of the lens group Ll and the fourth lens group L4 are performed by operating a cam mechanism fixed to the movable side of the bellows. By combining the movements of the cam mechanism, the movements of the lens group LI and the fourth lens group L4 as shown in FIG. 2 are 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 moves straight in the direction along the optical axis 0-0: $201a.

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 groups (Ll and L4) held in the movable lens group barrel. The bin 203 passes through the straight groove 201a of the fixed part 201 and is fitted into the cam f14202a 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 moves in the direction of arrow E.
move in the direction. 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 that the length of the cam groove 202a in the circumferential direction increases.

- Numerically, it is necessary to arrange multiple cam mechanisms,
Increasing L causes problems in terms of space. Furthermore, 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 bottle, furthermore, the positioning accuracy of the bottle becomes worse, and the position of the movable 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 an object of the present invention is to provide a lens barrel for close-up photography of this type that solves the above-mentioned problems.

(Means for Solving the Problems) The present invention is a lens device comprising a variable focal length photographing lens, a camera, and a telescoping intermediate device for mounting and supporting both on one side and the other side, The photographing lens has two or more variable power lens groups that move in the optical axis direction, and the variable power lens group is moved on a cam in conjunction with the amount of expansion and contraction of an intermediate device on which the photographic lens is mounted and supported. cam means for moving between a first position and a second position, the variable power lens group being moved from the first position to the second position by the cam of the cam means during the one-way expansion and contraction operation of the intermediate device; A lens device characterized in that it has a transmission means for returning the trajectory of the cam from the second position to the first position after the cam is moved to the first position.

(Function) That is, in the lens device of the present invention, the intermediate device (bellows) is provided with a transmission mechanism for reciprocating the movement of the bin with respect to the cam groove of the cam means for moving the variable magnification lens group of the photographing lens. The cam groove can be easily placed on the cam barrel of the lens, and the angle between the tangential line of the cam groove and the linear groove can be made relatively large, making it possible to create a lens with smooth movement of the bottle and good positioning accuracy. effective.

(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 which is fitted concentrically into this exterior ring with an annular gap and is integrally screwed together with the exterior ring; 3 is a front group cam cylinder which is fitted concentrically into this guide cylinder; It can be freely rotated forward and backward around the optical axis inside. 4 is the guide tube 2
A fixed lens barrel is integrally screwed concentrically with the guide barrel at the rear end and protrudes rearward from the rear end of the exterior ring l; 5 is a rear group cam that is externally fitted concentrically to the fixed lens barrel; It is a cylinder that can freely rotate forward and backward around the optical axis on the outside of the fixed lens barrel.

Reference numeral 6 denotes an annular mount fixed to the body at the rear end position of the exterior ring 1 with respect to the distal end flange portion of the fixed lens barrel 4, and for attachment to an intermediate device B, which will be described later. Therefore, the four members, the outer ring 1, the guide tube 2, the fixed lens barrel 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 lens barrel 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 at 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. Further, the cylindrical surface of the front group cam cylinder 3 fitted inside the guide cylinder 2 has a diameter of about 180° around the cylindrical circumference.
Edge calcam grooves 15 are provided at two opposing positions. The lens barrel 7 of the lens group fitted inside the front group cam barrel 3 is provided with a pin shaft 16 at two positions approximately 180° opposite to each other around the barrel circumference.
16, and their respective bottle shafts are connected to the front group cam cylinder 3.
Edge Calcam slot 15 and straight slot 12 of direct guide tube 2
The intersecting portions of both are penetrated and engaged. Therefore, the lens group lens barrel 7, that is, the lens group L1 moves forward in the optical axis direction within the front group cam tube 3 by rotating the front group cam tube 3 forward and backward around the optical axis with respect to the guide tube 2. Move backwards. 1
Reference numeral 7 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 front group cam barrel 3 in the forward direction. 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 circumferential groove hole 13 of the guide cylinder 2 at 91.
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 protrusion member 1B and the protrusion member 1B. 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 photographic lens A from the front (first lens group, side). It is strong.

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. Further, the cylindrical surface of the rear group cam cylinder 5 fitted onto the fixed lens barrel 4 is provided with edge cam grooves 22 at two positions approximately 180° opposite to each other around the cylinder periphery. Then, the fourth lens group barrel 10, which is fitted inside the fixed barrel 4, has a cylinder circumference of approximately 180 mm.
° Bottle shafts 23, 23 are installed at two opposing positions, and these bottle shafts are inserted into the intersection of the straight groove hole 21 of the fixed lens barrel 4 and the edge cam groove hole 22 of the rear group cam tube 5, respectively. The part is penetrated and engaged.

Therefore, the fourth lens group barrel 10, that is, the fourth lens group L4,
The rear group cam barrel 5 is rotated forward and backward about the optical axis with respect to the fixed lens barrel 4, thereby moving 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.

Reference numeral 27 denotes an interlocking pawl that is integrally provided on the outer surface of the rear 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 outer ring 1 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 folded 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, -L, and the aperture D are the first to fourth lens groups L1 to L4 in FIGS. 2 and 3,
and aperture D, and the rear group cam barrel 5 is the fixed lens barrel 4.
, the lens barrel 7 of the lens group, that is, the lens group LI%, and the fourth lens group barrel 1O, that is, the fourth lens group L4 are immobile along the optical axis. The second lens group moves away from the third lens group L3 (the second lens group moves forward along the optical axis, the fourth lens group moves forward along the optical axis,
On the contrary, the lens group L4 moves backward), or the second lens group L2.
The lens group moves in the direction approaching the third lens group L3 (the third lens group moves backward along the optical axis, and the fourth lens group L4 moves forward), and the lens group arrangement is as shown in Figure 2 (a). (c),
Figure 3 (a) and (c) short focus state array (magnification β
arrangement state of the seal or β3), or Fig. 2 (b) and Fig. 3 (
b) Steplessly changes to the long focal state array (array state with magnification β2 (same magnification)).

In the longitudinal 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.

■, Configuration of intermediate device B (Figs. 5, 9 to 13) In the vertical sectional side view in Fig. 5, the side view in Fig. 9, and the partially cutaway front view in Fig. 10, 50 is a long guide in the front and rear direction. Rail member, 5
0a is a rack fixedly provided along the length of the upper surface; 5
Reference numeral 1 denotes a support member (hereinafter referred to as the first support member) on which the photographing lens is attached, and is mounted on the guide rail member 50 so that the base side engages with the rail member in a dovetail groove and smoothly moves along the length of the rail member. It can be mounted freely and stably in forward and backward sliding movement. Reference numeral 52 denotes a support member (hereinafter referred to as a second support member) for mounting the camera, and on the rear side of the first support member 51, a dovetail groove is provided on the guide rail member 50 with the base side facing the rail member. In addition, the rail member can be smoothly and stably slid 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 first member 51 is engaged with the rack 50a on the guide rail member 50 side.
slides forward and backward along the rail member 50.

Similarly, regarding 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 be freely rotatably supported, and a drive knob shaft 57 is disposed in the middle thereof to be engaged with the rack 50a on the guide rail member 50 side. Matching pinion gears 59 are provided, and the second member 52 is slid forward and backward along the rail member 50 by rotating 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 annular interlocking gears that are integrally provided on each side of the interlocking rings 62 and 63 so as to be concentric 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 II shadow 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 forward and backward. The forward or reverse rotational force of the drive gear 56 is transmitted to the second interlocking gear 63b via the gear trains 01 to G7, and further transmitted to the first interlocking gear 62b via the differential gear G8. and the first and second
Although the two interlocking rings 62 and 63 have the same rotation angle, they are driven in forward and reverse directions in opposite 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 spring 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 No. 1, the electric signal assembly 28 on the photographing lens A side faces the electric signal assembly 65, and both assemblies 65 and 28 The corresponding bottles are pressed into 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 photographing lens A side.

For mounting the camera, in the second support member 52 as a support member, 67 is an opening for mounting the camera, and 68 is an annular mount for mounting the camera fixed on the back side of the member 52 and concentric with the opening 67.

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 contact with the electrical signal bin acenobluff 0 on the side, and both 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 mounted and supported on the second support member 52, the electric circuit on the camera C side and the electric circuit on the photographic lens A side are shown. The circuits are in contact with each other.

The snake [169] moves the first support member 51 and/or the second support member 52 forward and backward along the guide rail member 50 by rotating the knobs 54 and 58 in the forward and reverse directions to move the members 51 and 52.
When the mutual distance is changed, the opening 60 for inserting the photographing lens on the first support member 51 side and the opening 67 for camera installation on the second support member 52 side expand and contract depending on the size of the mutual distance. are constantly communicated through a dark path along the optical axis.

(2) Interlocking of the intermediate device IB and the photographing lens A The photographing lens of the intermediate device B (hereinafter referred to as bellows) is attached to the first support member 51, which is a support member, by fitting the photographing lens A into the first support member 51. 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 side of the photographic lens A is brought into contact with the mount 61 on the side of the first support member 51 by adjusting the rotation angle posture of the lens A, and further rotation of the photographic lens A in the clockwise direction is prevented by a stopper portion (not shown). Rotate enough until blocked. (Approximately 60' rotation operation in this example device)
As a result, the mounts 6 and 61 engage with each other and the photographing lens A
is stably attached and supported by the first support member 51. 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 barrel 5 of the photographic lens A is rotated. An interlocking pawl 27 protruding from the outer surface of the support member 51 contacts and is locked with the second interlocking pawl 63a on the first support member 51 side. For this reason, the rear group cam cylinder 5. This cam cylinder and key part 2
The rotation of the front group cam cylinder 3, which is integral with the outer ring 1 via the ring 5, is stopped at that point. The fixed m-barrel 4, which is fixedly connected, and the mount 6, which is integrally attached and fixed to the tip flange of this fixed lens barrel, are further rotated until further rotation is prevented by a stopper part (not shown). do.

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 portion 51 of the bellows B, the interlocking claw 2 of the rear group cam barrel 5 of the photographic lens A is moved to the first position by the reaction force of the spring 20 stretched as described above.
It is always pressed and kept in contact with the second interlocking pawl 63a on the side of the support member 51 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/reverse on the guide rail member 50, the forward/reverse rotation force of the drive gear 56 is transmitted to the second interlocking gear 6 via the gear train GING7.
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.
In conjunction with the forward and reverse rotations of lenses 3 and 62, the rear group cam barrel 5 of the photographing lens A is rotated in the forward and reverse directions around the outside of the fixed lens barrel 4. Also, the front group cam cylinder 3, which is integrated with the rear group cam cylinder 5 via the key member 25, is connected to the guide cylinder 2 together with the rear group cam cylinder 5.
Rotates forward and reverse inwardly. 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 L1%, and the fourth lens group lens barrel 10, that is, the fourth lens. The lens group L4 is moved and driven along the optical axis in the direction away from or toward the second lens group L2, the diaphragm D, and the third lens group L3, which are stationary, respectively. , Figure 3(a) (C)
Stepless method for short focal length lens array (magnification 8 plates or β3 array) or long focal length lens array (magnification β2 (same magnification)) as shown in Figures 2(b) and 3(b). Changes to

■Specifically, when changing the magnification from the low magnification side (imaging magnification βI) to the high magnification side β, → β2 → β3 in FIG. 2(a), turn the knob 54 of the first support member 51 of the bellows B. It is rotated in the normal direction to move 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 the lens A and the bellows h 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.
If you move it forward to a position closer to the tip of 0, the imaging magnification will be
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 hollow portion side.

By the above operation ■→■→■, the rear group cam tube 5 of the photographic lens A is
And the front group cam cylinder 3 is connected to the interlocking rings 63 and 62 of the bellows B.
With the movement of , from low magnification β to equal magnification β2 to equal magnification β2
The direction of rotation is reversed from to high magnification β3. The movements of each of the lens groups Ll to L4 and the aperture D are as shown in FIG. Further, the movements of each of the lens groups L1 to L4 and the diaphragm D with respect to the planned image forming plane F (the film plane in the camera C) are as shown in FIG.

Furthermore, a front group biasing spring 17 is installed between the first lens group lens barrel 7 and the tip of the exterior ring 1, and a front group biasing spring 17 is installed between the first lens group lens barrel 7 and the tip of the outer ring 1.
The urging 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 position of the bottle shaft 16 relative to the hemlock cam slot 15 is pressed in one direction by the urging force, the positional accuracy of the bottle shaft 16 can be determined with high precision.

Further, a rear group biasing spring 24 is installed between the fourth lens group barrel 10 and the end of the fixed lens barrel 4, and biases the fourth lens group barrel 10 in the extension direction. The spring 24 of the pin shaft 23 fitted into the edge cam slot 22 of the rear group cam cylinder 5
It helps the movement in the elongation direction. At the same time, since the position of the bottle shaft 23 relative to the edge cam slot 22 is pressed in one direction by the urging force, the positional accuracy of the bottle shaft 23 can be 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 0 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 lens device of this embodiment is configured to reciprocate the interlocking member that transmits the amount of expansion and contraction of the intermediate device B (bellows) to the photographic lens A, so that: ■ the variable magnification lens group of the photographic lens A, -L Cam means (cam tube) for moving 3.
It is now possible to increase the cam intersection angle θ (Fig. 6) of No. 5, smoothing the lens group movement and improving the positional accuracy of the variable power lens group.

■# to intermediate device B! The installation of the shadow lesbian A is within the angle,
Interlocking members 63a, 62a, between intermediate device B and photographic lens A
We were able to achieve a rotation angle of the cam cylinder that would allow 27 initial settings.

(Effects of the Invention) As explained above, the lens device of the present invention has an intermediate device (
By providing a transmission mechanism for reciprocating the movement of the bottle relative to the cam groove of the cam means for moving the variable magnification lens group of the photographic lens in the bellows, the cam groove can be easily placed in the cam barrel of the lens. Since the angle between the tangent of the cam groove and the rectilinear groove is relatively large, it is possible to realize a lens with smooth movement of the bottle and good positional density.

[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 imaging magnification, and Figure 5 is a longitudinal side view of the device.
Figure 6 is a developed plan view of the main part of the photographic lens (cam mechanism).
Figures 7 and 8 are a plan view and side view of the photographic lens, Figure 9 is a side view of the intermediate device (bellows), Figure 10 is a partially cutaway front view, Figures 11, 12, and FIG. 13 is an explanatory diagram 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 the conventional cam mechanism. A is the photographing lens (focal length variable Il shadow lens), B is the intermediate device (bellows), C is the camera, L, ~L4 are the first ~
4th lens group, D is an aperture, 5152 is a support member (first support member) for mounting the photographing lens of the intermediate device, a support member (second support member) for camera mounting, 50 is a guide rail member,
54.5B is a support member movement operation knob.

Claims (1)

[Claims] (1) A lens device consisting of a variable focal length photographing lens, a camera, and a retractable intermediate device for mounting and supporting both on one side and the other, and the photographing lens moves in the optical axis direction. The variable power lens group is moved between a first position and a second position on a cam in conjunction with the amount of expansion and contraction of an intermediate device on which the photographing lens is mounted and supported. cam means for moving the variable power lens group from the first position to the second position by the cam of the cam means during the unidirectional expansion/contraction operation of the intermediate device; A lens device comprising a transmission means for returning the trajectory of the cam from the position to the first position.