JPS62273504A - Photographing lens barrel - Google Patents

Abstract

PURPOSE:To prevent shifting of a focusing position, by providing an operating force switching means which gives rotational resistance to an operation ring at the 1st position and releases the rotational resistance at the 2nd position. CONSTITUTION:An operating force switching means is composed of an inner tube 30, switching ring 40, wave washer 6, and L-groove 52 of a cover ring 50, and a switching member 300 is constituted of the inner tube 30 and switching ring 40. At the 1st position, at which the projection 42 of the switching ring 40 from its inner periphery is positioned in the groove section 52a of the L- groove 52 provided in the outer peripheral surface of the cover ring 50, the rotational movement of this lens barrel is restricted by both side sections 54 and 55 of the L-groove 52. At the 2nd position, at which the switching ring 40 is turned in the direction C after it is brought into contact with the wall 53 of the L-groove 52, the left end section 33 of the inner tube 30 is separated from the inner wall 14 of an operation ring 10 and the rotational resistance by means of a wave washer 6 is released. Therefore, the arbitrary movement of a focusing lens in the optical direction can be eliminated and using conditions of this lens barrel is improved.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention A. Field of Industrial Application The present invention relates to a photographic lens for an autofocus camera in which a focusing lens is driven by a motor based on a distance measurement signal to focus. Regarding the lens barrel.

B. PRIOR TECHNOLOGY Conventionally, in this type of photographic lens barrel, in addition to the automatic mode using an automatic focus adjustment mechanism, there is an operation ring for focus adjustment provided on the outer periphery of the lens barrel, i.e. It also has a manual mode in which the focus adjustment lens in the lens barrel is moved along the optical axis and focused by manually operating the distance ring.

In automatic mode, for example, a motor built into the camera body and driven based on a distance measurement signal moves the focusing lens through a mechanical connection between the camera body and lens barrel to achieve focusing. Therefore, it is desirable that the member driven for focusing be configured to move with as little force as possible. In the manual mode, focusing is performed by manually rotating the distance ring described above and moving the focusing lens along the optical axis. If the torque of this distance/ring is too large, a large amount of force is required for operation, making it difficult to use.If it is too small, the distance will automatically increase due to the weight of the internal optical system and the weight of hardware, especially when shooting in the vertical direction. The ring rotates (referred to as a self-weight drop phenomenon) and becomes out of focus. In this case, you must always keep your hand on the distance ring, which is inconvenient. In particular, in the case of close-up lenses used for close-up photography, copying, etc., the amount of movement per rotation of the distance ring is extremely large compared to other lenses, as they are capable of shooting up to 1:1 magnification, resulting in the phenomenon of dead weight drop. becomes noticeable. Therefore, it is desirable that the operating ring be operated with a torque intermediate between these.

In this way, in an autofocus camera, the required torque of the operating ring is different in automatic mode and manual mode, but conventionally, the operating ring is It can be operated with relatively small torque.

In addition, in this type of photographic lens for an autofocus camera, a pin protruding outward from the frame of the focusing lens is loosely fitted into a lead groove formed in a fixed lens barrel, and the pin is formed into an operating ring. Focusing is performed by moving the lens in the direction of the optical axis along the straight groove.

C0 Problems to be Solved by the Invention However, when performing close-up photography with a conventional autofocus camera, the lens beam for close-up photography becomes very large, so it is difficult to use the lens barrel as in the case of close-up photography or copying. If it is oriented in the vertical direction, the above-mentioned dead weight falling phenomenon may occur. In automatic mode, there is no problem because the automatic focusing mechanism always controls the focusing lens to the in-focus position, but in manual mode, the automatic focusing mechanism on the lens barrel side and the camera body Since the mechanical connection with the lens is released, the operating ring must be held at all times to prevent the focusing position from shifting due to the phenomenon of weight falling, making it inconvenient to use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photographic lens barrel that solves the above-mentioned problems by applying a load resistance to the operating ring during the 1-manual mode.

Means for Solving Problem D1 The present invention is provided with an operation force switching means that applies rotational resistance to the focus adjustment operation ring 10 in the first position and releases the rotational resistance in the second position. It consists of

81 When the operation force switching means is operated to the first position, rotational resistance is applied to the operation ring 10, and when it is operated to the second position, the rotational resistance is released. Therefore, by operating the operating force switching means to the first position in the manual mode and to the second position in the automatic mode, the rotational torque of the operating ring 10 can be set appropriately.

F. Embodiment 1 First Embodiment A first embodiment will be described based on FIGS. 1 to 7.

In FIG. 1, a lens holder l holding a lens Ll and a lens L2 is slidably fitted into the inner peripheral surface of a manual operation ring (distance ring) 10 provided with a long groove 11 parallel to the optical axis. equipped. A pin 2 implanted on the outer circumferential surface of the lens holder l fits into the long groove 11, and the tip of the pin 2 is further attached to the inner circumferential surface of the fixed lens barrel 20 into which the operating ring 10 is inserted. It fits into the groove 21. Further, a segment gear 12 is formed on the inner peripheral portion of the operation ring 10 on the mount side, and a third
As shown in the figure, it meshes with the idle gear 3. The idle gear 3 meshes with another idle gear (not shown) that meshes with a gear 5 integrally provided on a shaft 4 to which rotational force is transmitted from a motor (not shown) built into the camera body. A circumferential groove 13 is formed on the outer circumference of the operating ring IO near the segment gear 12, and a ring-shaped protrusion 22 protruding from the inner circumferential surface of the fixed lens barrel 20 is engaged with the circumferential groove 13. . Therefore, although the operating ring 10 can rotate around the optical axis, movement along the optical axis is prohibited.

Further, in FIG. 1, the inner tube 30 is fitted to the outer circumference of the tip of the fixed lens barrel 20 so as to be movable in the optical axis direction. It is urged in the direction A in the figure by the wave washer 6 fitted between the outer peripheral flange portion 23 and the outer peripheral flange portion 23 . In addition, wave washer 6
The wave washer 6 has a waveform so that the inner tube 30 is biased parallel to the optical axis, thereby preventing the fixed lens barrel 20 from being deformed by the force of the wave washer 6 in the optical axis direction.

The switching ring 40 is fitted onto the outer periphery of the inner cylinder 30, and its right end 41 is fitted into the large diameter portion 51 of a cover ring 50 fitted onto the outer periphery of the fixed lens barrel 20. V- in Figure 4
(2) As shown in FIG. 5, which is a developed view in the direction of arrows, an L-shaped groove 52 is formed in the cover ring 50, and the L-shaped groove 52 is closed by the outer peripheral flange 23 of the fixed lens barrel 20.

The inner peripheral protrusion 42 of the switching ring 40 is loosely fitted into the closed L-shaped groove 52. Therefore, the switching ring 40 is movable upward in the figure (to the left in FIG. 1) until the inner circumferential protrusion 42 abuts the outer circumferential collar 23, and until it abuts against the wall 53 of the cover ring 50. It is movable downward (rightward in FIG. 1). As shown in FIG. 1, the inner circumferential step 43 formed at the left end of the switching ring 40 engages with the outer circumferential step 32 formed at the left end of the inner cylinder 30.

In the above configuration, the inner cylinder 30. Switching ring 40, wave washer 6. The L-shaped groove 52 of the cover ring 50 allows the operating force switching means to be connected to the shaft 4. Idol gear 5. Operation ring 10
The segment gears 12 constitute an automatic focusing mechanism on the lens barrel side. Furthermore, a switching member 300 is configured by the inner cylinder 30 and the switching ring 40.

Focusing and switching of the operating torque of the operating ring in the photographing lens barrel configured as described above will be explained.

First, focusing will be explained.

In the manual mode, when the operating ring 10 is rotated by gripping its outer circumference 15, the pin 2 of the lens holding frame l moves straight through the long groove 11 by the lead groove 21 of the fixed lens barrel 20, and is used for focus adjustment. Lenses Ll and L2 are moved along the optical axis, thereby performing focusing.

In the automatic mode, when the motor built into the camera body rotates based on the ranging signal, the shaft 4 and gears 5 and 3 rotate via the coupling 7 shown in FIG. The operating ring 10 is rotated through the lens, and focusing is performed in the same manner as in the manual mode.

Next, operation torque switching will be explained.

When performing the focus iA section in manual mode, the switching ring 40 is moved to the first position as shown in FIGS. 1, 4, and 5.
Operate to the position. In this first position, as shown in FIG.
The rotational movement is restrained by both sides 54 and 55 of the L-shaped groove 52. Furthermore, as shown in FIG. 1, the switching ring 40 is biased in the same direction as the inner barrel 30 by the biasing force of the wave washer 6 through the inner barrel 30. The inner peripheral protrusion 42 of the switching ring 40 remains in contact with the flange portion 23. In this state, the left end 33 of the inner cylinder 30 is in contact with the inner wall 14 of the operating dowel 10 with a predetermined contact pressure. Therefore, when the operating ring 10 is rotated, the inner wall 14 of the operating ring 10 rotates while sliding on the left end 33 of the inner cylinder 30, causing rotational resistance, increasing the rotational torque of the operating ring 10, and as a result. , the so-called self-weight drop phenomenon can be prevented, and the in-focus position of the focusing lens can be maintained even if the operator does not put his or her hand on the operating ring 10.

When using the autofocus camera in automatic mode, the switching ring 40 is operated to the second position as shown in FIGS. 2, 6, and 7. That is, the switching ring 40
Grasp the outer circumferential surface of the wave washer 6 with your fingers and move it in the direction of arrow B in FIGS. Then, further rotate it in the direction of arrow C in FIG. 6th
As shown in Figure 7, which is a developed view of the ■-■ arrow plane in the figure,
The inner peripheral protrusion 42 of the switching ring 40 is connected to the L of the cover ring 50.
The inner peripheral protrusion 42 of the switching ring 40 is fitted into the groove 52b of the groove 52, and is fixed by moving toward the mount surface by an amount in the optical axis direction. At this time, the inner peripheral stepped portion 4 of the switching ring 40
3 moves the inner cylinder 30 in the same direction via the outer circumferential step 32, as shown in FIG.
3 is separated from the inner wall 14 of the operating ring 10, and the rotational resistance caused by the wave washer 6 is released. As a result, the operating ring l
O can be rotated even with a small torque, and the load on the automatic focus adjustment motor is reduced.

Switching from the automatic focus mode to the manual mode can be achieved by rotating the switching ring 40 in the direction of the arrow in FIG. 52a, the wave washer 6 is biasing the inner cylinder 30 in the inward direction, so the switching ring 40 is also biased by the wave washer 6 via the inner cylinder 30, and as shown in FIGS. The state shown in FIG. 5 is reached, and the switching ring 40 is switched to the first position suitable for the manual mode.

- Second Embodiment - The second embodiment shown in FIG. 8 is based on the inner cylinder 30 shown in FIG.
is integrated with the switching ring 40 to form an annular switching member 300, and the other configurations are the same as in the first embodiment.

Note that the present invention can also be applied to a lens barrel that includes a built-in motor for driving a focusing lens.

G6 Effects of the Invention According to the present invention, even if the operating torque of the operating ring is set in advance so as to reduce the load on the motor that drives the focusing lens, when focusing is performed manually, the operating force switching means is used. Since the structure is configured so that rotational resistance can be applied to the operating ring, when shooting in manual mode with the camera pointing in the direction of earthworks, the focus adjustment lens will not move automatically in the optical axis direction due to the so-called self-weight drop phenomenon. We can provide an autofocus camera that is easy to use and easy to use.

[Brief explanation of the drawing]

1 to 7 show a first embodiment of the present invention, FIG. 1 is a sectional view when rotational resistance is applied to the operating ring, and FIG. 2 is a sectional view of the main part when rotational resistance is removed. Figure 3 is a sectional view of the main part showing the automatic focus adjustment mechanism on the lens side, and Figure 4 is a sectional view of the main part showing the automatic focus adjustment mechanism on the lens side.
Fig. 5 is a developed view of the v-■ arrow plane of Fig. i4, Fig. 6 is a sectional view taken along the VT-Vl line of Fig. 2, and Fig. 7 is a sectional view of - ■Developed view from arrow plane, Figure 8 is ER2
FIG. 6: Wave washer IO: Operation ring 20: Fixed lens barrel 30: Inner barrel 40: Switching ring 5
0: Covering 300: Switching member

Claims (1)

[Scope of Claims] 1) A photographing lens mirror comprising: an operation ring capable of manually driving a focus adjustment lens; and an automatic focus adjustment mechanism that drives the focus adjustment lens with a motor based on a distance measurement signal. 1. A photographic lens barrel, characterized in that the barrel is equipped with an operating force switching means that applies rotational resistance to the operating ring in a first position and releases the rotational resistance in a second position. 2) The operating force switching means engages a switching member fitted into a fixed lens barrel adjacent to the operating ring, an elastic body that urges the switching member in a direction into contact with the operating ring, and the switching member engages. In the first position, the switching member is allowed to come into contact with the operating ring due to the biasing force of the elastic body, and in the second position, the switching member is allowed to contact the operating ring against the biasing force. 2. The photographing lens barrel according to claim 1, further comprising an engaging groove that prohibits contact. 3) The switching member is fitted into the inner cylinder which is made contactable with the operation ring by the elastic body, and is fitted onto the outer periphery of the inner cylinder and engages with the engagement groove, and in the first position, the inner cylinder The photographing lens according to claim 2, further comprising an outer barrel that allows the barrel to come into contact with the operating ring and separates the inner barrel from the operating ring in the second position. lens barrel.