JPH0229725A - Focal distance switching device for camera - Google Patents

Abstract

PURPOSE:To surely switch a focal distance by providing a pressing member, a cushioning member, a switching member and a locking member and locking the switching member with the aid of the locking member when the switching member is positioned at the trailing end of the switching of a focal distance. CONSTITUTION:When the pressing cam 65 is rotated based on a TW switching signal and a first TW switching lever 60 is rotated toward a wide side, a second TW switching lever 61 is rotated large. Due to the initial large rotating displacement, a conversion lens 38 can be immediately refuged from an optical axis L by a lens going in and out mechanism 39. Thus, a moving barrel 30 can be prevented from coming into collision with the conversion lens 38 when it is set back. Besides, since a second pin 101 abuts on a second cam 106 when the first TW switching lever 60 is positioned near the trailing end of moving, the second TW switching lever 61 can be positioned to the trailing end with high accuracy by the second cam 106.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a focal length switching device for a camera, and particularly to a focal length switching device that smoothly and quickly transmits motor rotational force for focal length switching. Regarding equipment.

[Conventional technology]

For example, in a 35mm compact camera, the focal length is 3.
Wide shooting (wide-angle shooting) of about 5 cranes and focal length of 70w
A camera with a focal length switchable type that can switch between telephotography (telephotography) and telephotography is known.

In this type of camera, the conversion lens is generally moved in and out of the optical axis of the master lens, and when shooting at wide angles, the conversion lens is retracted out of the optical path.
During telephoto shooting, the master lens is moved forward and at the same time the conversion lens is inserted into the optical path to switch the focal length.

This focal length switching can be done, for example, in Japanese Patent Application Laid-Open No. 60-114
As proposed in Japanese Patent Laid-Open No. 836, a toggle spring that can bias the master lens in the direction of protruding the master lens from the fixed lens barrel and in the direction of storing it in the fixed lens barrel, or as proposed in Japanese Patent Laid-Open No. 163010/1989, As proposed in Japanese Patent No. 61-35435, etc., there is a method that uses a motor for feeding the film and performs the process electrically.

[Problem to be solved by the invention]

However, although the above-mentioned device that switches the focal length using a toggle spring can simplify the configuration, it has the problem that it requires a large operating force to switch the focal length because it uses the resilient restoring force of the toggle spring. be.

Further, when the focal length is switched using a film feeding motor, rotational force is generally obtained from the film feeding motor using a clutch mechanism consisting of a planetary gear mechanism. However, in this case, by changing the rotation direction of the sun gear, the planetary gear that meshes with it is made to revolve and the rotational force of the motor is transmitted to the target drive gear. If the drive gear side is not in a freely rotatable state during revolution, the engagement between the drive gear and the planetary gears will not be good, and smooth rotation transmission will not be achieved, making it difficult to quickly change the focal length. There is a point.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a focal length switching device for a camera that smoothly and quickly transmits a motor rotational force for switching the focal length.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a pushing member that is arranged in a focal length switching system and driven by a motor, and a buffer member that elastically contacts and displaces the pushing part of the pushing member. ,
A switching member that is pushed by a pushing part through this buffer member to move the photographic lens in the optical axis direction and switch the focal length; A locking mechanism that locks the buffer member by forming a gap between the buffer member and the pushing part when the pushing part is positioned at the position, and releases this locked state by pushing the pushing part again. It is constructed from members. Further, the pushing member is composed of a pushing cam that rotates half a rotation when switching the focal length, the pushing part is composed of a pushing pin eccentrically provided to the pushing cam, and the switching member is composed of a switching lever. , the buffer member is constituted by a buffer lever that is swingably attached to the switching lever and elastically resists the pushing of the push pin by a spring, and the locking member is configured to lock the buffer lever. In order to simplify the structure, it is preferable to use a locking lever that is engaged with the push pin and released from the locked state by rotation of the push cam after locking.

[Effect]

When a mode switching button such as a TW switching knob is turned on to switch the focal length, the motor rotates forward, for example, to switch the focal length. As a result, the clutch is switched to the focal length switching side, the rotational force of the motor is transmitted to the focal length switching system pushing member, and the pushing member pushes the buffer member.

When the buffer member is pushed, the focal length switching member to which it is attached is also pushed, thereby switching the focal length and switching the photographing lens from, for example, the telephoto side to the wide side.

At the end of this switching, the buffer member is locked by the locking member. This locking occurs when the buffer member is displaced by the push of the pushing member and when the switching member is located at one end of the focal length switching, so the shift caused by the push of the buffer member makes the buffer member elastic. A restoring force acts, which causes the focal length switching member to be locked at one end of the focal length switching. Therefore, by locking the focal length switching member, a gap is formed between the pushing member and the buffer member with which it comes into contact, and this gap maintains the pushing member in a free state. As a result, again,
Even if the clutch is activated to change the focal length, the rotational force of the motor is smoothly and quickly transmitted to the free pushing member through the clutch, so that the focal length can be changed reliably. Furthermore, even when the pushing member pushes the focal length switching member, it is done via the buffer member, so this buffering member absorbs the displacement of the connection position between the focal length switching member and the pushing member. The amount of movement of the photographic lens can always be maintained constant, and defocus can be prevented.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

In FIG. 2, which shows a focal length switching camera embodying the present invention, a fixed barrel 11 projecting forward is formed on the front plate IO. This fixed tube 11 is provided with a lens cover opening/closing knob 12, and when this knob is slid, a pair of lens covers 13 and 14 rotate to open and close the opening 15. In addition, a tele/wide (hereinafter referred to as TW) switching knob 16 is provided on the front plate lO, and when this is pushed down, it switches to wide shooting if the tele shooting state is set, or wide If set to shooting, it can be switched to telephoto shooting. In addition, T.W.
To prevent the telephoto from cyclically switching between the darkest and wide shooting modes even if the switching knob 16 is held down, the switching knob 1 should be pressed once.
The TW switching is completed by the operation in step 6.

Further, above the front plate 10, a well-known finder window 18,
Distance measuring windows 19 and 20 and a strobe light emitting section 21 are provided, and furthermore, a release button 22 is provided at the top of the front plate 10.

FIG. 3 shows an outline of the optical system. Moving cylinder 3・θ
Inside is a lens holder 3 holding a master lens 31.
2 are slidably fitted together, and can be moved along the optical axis within the movable tube 30 to adjust the focus using a well-known distance measuring device (not shown). . A guide member 33 protrudes from one side of the movable cylinder 30, and a bearing portion 34 is attached to this. A guide rod 35 extending in the direction of the optical axis is inserted into the bearing section 34, and the movable barrel 30 is moved between the telephoto shooting position where the master lens 31 is extended forward and the wide shooting position where the master lens 31 is moved backward. will guide you when moving. Further, a coil spring 36 is inserted through the guide rod 35, and the movable cylinder 30
is biased toward the telephoto shooting position.

A conversion lens 38 is located behind the movable barrel 30.
is located. This conversion lens 38 is
In conjunction with the movement of the movable barrel 30, the lens is moved in and out of the optical axis of the master lens 31 by the lens in/out mechanism 39. The lens loading/unloading mechanism 39 includes an arm 40 with a conversion lens 38 attached to its tip, a fan-shaped lens loading/unloading gear 42 with the arm 40 attached, and a fan-shaped swinging gear 44 with a swinging arm 43. has been done.

Further, a spring 45 is applied to the arm 40, and urges the conversion lens 38 in four directions for insertion into the optical axis.

Further, a behind shutter 46 is arranged behind the conversion lens 38. As is well known, the behind shutter 46 includes two shutter blades 47 and 48, and by moving the opening/closing pin 50 toward a fixed pin 49 that pivotally supports these blades, the two shutter blades 47 and 48 can be moved.
．． 48 can rotate in opposite directions to open the photographing optical path. Further, a throttle device (not shown) is attached to the rear part of the movable cylinder 1.

In order to move the master lens 31 and the conversion lens 38 in conjunction with each other, the first and second TW switching levers 60 and 61 are attached to a substrate (not shown) on a shaft 62.
．． It is rotatably attached via 63. The first TW switching lever 60 is connected to a push cam 65 as described later.
The movable tube 30 is moved along the optical axis by contacting the push pin 66 of the movable tube 30, and the pin 67 implanted at the tip is inserted into the elongated hole 68 of the guide member 33 of the movable tube 30. It is slidably inserted. Second TW switching lever 61
has its tip in contact with the swinging arm 43 of the lens loading/unloading mechanism 39, and when it engages with the first switching lever 60 and swings, it moves the conversion lens 38 in and out of the optical axis. It is being done.

As shown in FIG. 3, the first TW switching lever 60 is always urged to rotate toward the telephoto side (clockwise in the figure) by a coil spring 36 that urges the movable cylinder 30 forward. Further, the first TW switching lever 60 is rotated by a predetermined angle by a push cam 65, as shown in FIG. 1, against the bias of the coil spring 36. The push cam 65 is rotated approximately half a rotation by a push cam half rotation means 70. A push pin 66 is implanted in the push cam 65 at a position eccentric from the center of rotation. This pin 66 is displaced upward in the figure to the wide side as the push cam 65 makes a half turn, so that the T
The first TW switching lever 60 rotates counterclockwise in the figure via the W bend lever 80. In addition, the push cam 65
is further rotated by half a turn and the push pin 66 is displaced downward in the figure to the telephoto side, whereby the first TW switching lever 60 rotates clockwise in the figure.

The rotational force of the motor 71 is selectively transmitted to the pushing cam half-rotation means 70 by a planetary gear mechanism 72 serving as a clutch mechanism depending on the rotation direction thereof. That is, when the motor 71 rotates forward, the planetary gear 74 that meshes with the sun gear 73 on the motor 71 side revolves so as to mesh with the drive gear 76 of the film winding means 75 in order to wind the film frame by frame. The rotational force of the motor 71 is transmitted to the film winding means 75. Further, when the motor 71 reverses rotation, the planetary gear 74 revolves so as to mesh with the drive gear 77 on the pushing cam half-rotating means 70 side, and meshes with this to transfer the rotational force of the motor 71 to the pushing cam half-rotating means 70. to communicate.

Also, when rewinding the film after shooting, the motor 7
1 is reversed and the arm 78 is locked so that the revolution of the planetary gear 74 is restricted, so the push cam 65 does not rotate (and only rewinds the film).

The TW bend lever 80 is attached to the first TW switching lever 60 via a shaft 81 so as to be swingable. A contact piece 82 is bent at one end of the TW bend lever 80 and is slidably contacted by the push pin 66 . Further, a coil spring 85 that biases the contact piece 82 toward the push pin 66 is stretched between the TW pend lever 80 and the first TW switching lever 60. Note that the end 86 of the coil spring 85 is attached to the TW switching lever 60 side to which one end is fixed by bending a part of the TW switching lever 60.
also acts as a stopper to restrict the rotation of the TW pend lever BO. In addition, the contact piece 82 of the TW bend lever 80
A locking piece 87 is provided proximate to.

A lock lever 90 is provided for locking the rotation of the first TW switching lever 60 by engaging the locking piece 87 when the first TW switching lever 60 rotates to the wide end position. This lock lever 90 has a locking piece 87
It is provided with a locking pawl 91 for locking, and is rotatably attached to the substrate by a shaft 92. Further, this lock lever 90 is urged counterclockwise in the figure by a coil spring 93, and the locking piece 87 overcomes the locking pawl 91 against the urging of this coil spring 93, so that the lock lever 90 As a result, the first TW switching lever 60 is locked at the wide end.

That is, when the push cam 65 rotates about half a turn and reaches a state immediately before stopping, the push pin 66 comes off from the contact piece 82 of the TW bend lever 80, as shown in FIG. Therefore, the pushing of the first TW switching lever 60 by the pushing pin 66 is released, but the lock lever 90 and the TW bending lever 8
0, the first TW switching lever 60 is locked, so the first TW switching lever 6o will not return to the telephoto side. Thereby, the first TW switching lever 60 can be locked on the wide side by the lock lever 9o, and the push cam 65 is maintained in a free state.

Next, with reference to FIG. 6, the interlocking of the first and second TW switching levers 60, 61 will be described.

The first TW switching lever 60 has first and second pins 100 and 101 implanted therein. The first pin 100 is
It is in slidable contact with the first cam 103 of the second TW switching lever 61. This first cam 103 rotates the first TW switching lever 60 at an initial small rotation angle α1 toward the telephoto side.
With respect to the large displacement cam portion 104 that obtains a large lift amount β1 and the subsequent rotation angle α2 of the first TW switching lever 60, the lift amount (rotation angle) β2 is small or the lift amount β is
2 and a small displacement cam portion 105. Further, the second cam 106 that the second pin 101 contacts is connected to the first cam 106.
This is for precisely positioning the rotation end of the second TW switching lever 610 when the TW switching lever 60 is located near the end of its movement.

Therefore, when the push cam 65 rotates based on the TW switching signal and the first TW switching lever 60 rotates to the wide side as described above, the first TW switching lever 60 rotates through the first cam 103 and the first pin 100 at the initial stage of rotation. Then, the second T/W switching lever 61 becomes thicker (rotates).

Due to this initial large rotational displacement, the convergence run lens 3B can be immediately retracted from the optical axis by the lens in/out mechanism 39. As a result, the converge run lens 38 can be immediately retracted from the optical axis at the same time that the movable barrel 30 starts retreating, and the movable barrel 30 is prevented from colliding with the converge run lens 38 when the movable barrel 30 is retreating. be able to. Further, when the first TW switching lever 60 is located near the end of movement, the second pin 1
01 contacts the second cam 106, this second cam 1
06, the second TW switching lever 61 can be accurately positioned at its terminal position.

Next, the operation of this embodiment will be explained.

When taking a picture, first slide the lens cover opening/closing knob 12 to open the lens cover 13 and 14.

When the lens covers 13 and 14 are moved to the open position, the main switch (not shown) is turned on and the motor 7 is turned on.
The drive circuit No. 1, the shutter drive circuit, the distance measuring device, the strobe circuit, etc. are energized.

When the lens covers 13 and 14 are open, 2 is shown in Figure 3.
As shown by the dotted chain line, the camera is in wide shooting mode.
The movable cylinder 30 is set at a position where it has retreated and entered the movement range of the arm 40.

In this wide shooting state, when the release button is pressed, the distance measuring device operates and moves the lens holder 32 along the optical axis according to the subject distance to adjust the focus of the master lens 31. The behind shutter 46 operates to expose the film.

After this shutter operation, as shown in FIG. 1, the motor 71 rotates and its rotational force is transmitted to the film winding means 75 via the planetary gear mechanism 72. This results in
The take-up spool rotates to take up the exposed film A around its outer periphery, and sets the unexposed film pulled out from the cartridge into the exposure position. Further, shutter charging is performed in conjunction with this film winding.

Next, when switching from the wide shooting state shown by the two-dot chain line in Fig. 3 to the telephoto shooting state shown by the solid line, T
All you have to do is slide the W switching knob 16. In this wide shooting state, the first TW switching lever 60 is locked at the wide side position by the lock lever 90, so the push cam 65 has the push pin 66 in the It is said to be in a free state located in the upper middle part.

In this state, when the TW switching knob is slid, a TW switching switch (not shown) is turned on in conjunction with this, and the motor 71 is rotated in the reverse direction. As a result, as shown in FIG. 1, the planetary gear 74 of the planetary gear mechanism 72 revolves so as to mesh with the drive gear on the push cam half-rotation means 70 side, so that the rotational force of the motor 71 is applied to the push cam. This is transmitted to the half-rotation means 70, and the push cam 65 begins to rotate counterclockwise in the figure.

When the push cam 65 begins to rotate counterclockwise, the push pin 66 first comes into contact with the tip of the lock lever 90 and rotates the lock lever 90 clockwise in the figure. This results in
The locked state of the TW bend lever 80 by the lock lever 90 is released, and the first TW switching lever 60 is moved to the movable cylinder 3.
It rotates clockwise in the figure by a coil spring 35 that biases the lens toward the telephoto side. Due to this rotation, the movable cylinder 30 is moved forward, and in conjunction with this, the second TW switching lever 6
1 begins to rotate. Therefore, as shown by the broken line in FIG.
05, the rotation angle β2 of the second TW switching lever 61 is smaller (compared to the rotation angle α2 of the first TW switching lever 60), so even if the movable cylinder 30 moves forward, The conversion lens 38 is not displaced much.

By rotating the first TW switching lever 60, the first cam 1
00 transfers from the small displacement cam section 105 to the large displacement cam section 104, the action of the large displacement cam section 104 causes the first
For the rotation angle α1 of the TW switching lever 6o, the second
The rotation angle α2 of the TW switching lever 61 increases,
The conversion lens 38 is quickly inserted into the optical axis.

In this way, the movable barrel 30 is fully extended forward, and after the insertion space for the conversion lens 38 is formed behind it, the conversion lens 38 is inserted into the optical axis. 3
8 can be prevented from colliding. In this way, it is possible to switch to the telephotography state as shown by solid lines in FIGS. 1 and 3.

Next, the case of switching from the telephoto shooting state to the wide shooting state will be described. In the telephoto shooting state as shown in FIG. 1, when the TW switching knob 16 is pressed, the rotational force of the motor 71 is transmitted to the push cam 65 via the push cam counter-rotation means 7o. When the pushing cam 65 rotates counterclockwise in the figure, the upward displacement of the pushing pin 66 causes the first TW bend lever 80 and the coil spring 85 to
The switching lever 60 rotates counterclockwise. As a result, the movable cylinder 30 moves toward the wide side against the bias of the coil spring 35. With this movement, the conversion lens 38
I also evacuate along the optical axis.

That is, as shown by the solid line in FIG.
Since the first pin 1oo of the switching lever 60 is in contact with the large displacement cam portion 104 of the second TW switching lever 61,
The rotation angle β1 of the second TW switching lever 61 becomes large compared to the small rotation angle α1 of the first TW switching lever 6°. Therefore, when the movable barrel 30 is slightly displaced to the wide side, the conversion lens 38 rotates greatly so as to retreat from the optical axis. Therefore, the conversion lens 38 quickly retreats from the optical axis before the movable barrel 3o moves rearward, so that it is possible to reliably prevent the movable barrel 30 from colliding with the conversion lens 38. Furthermore, when the first TW switching lever 60 is located at the wide end, the second pin 101 comes into contact with the second cam 106 of the second TW switching lever 61, so that the conversion lens 38 can be positioned with high precision. It can be carried out.

When all the frames of the film have been photographed, as is well known, the motor 71 is automatically started to reverse rotation to rotate the rewind claw. When this rewind claw rotates, the exposed film wound around the spool is rewound into the cartridge.

Note that in the above embodiment, the first switching lever 60
Although the conversion lens 38 is inserted into the optical axis of the master lens 31 by switching the second switching lever 61 in conjunction with this, the present invention is not limited to this; Insertion into the cage can also be accomplished using other mechanisms.

〔Effect of the invention〕

As explained above, according to the present invention, the pushing portion 4° is provided with a material, a buffer member, a switching member, and a locking member, and when the switching member is located at one end of focal length switching, the locking member is activated. Since the switching member is locked, a gap is formed between the pushing member and the buffer member with which it comes into contact, and the pushing member is maintained in a free state by this gap. As a result, even if the clutch is activated to change the focal length again, the rotational force of the motor is smoothly and quickly transmitted to the free pushing member through the clutch, ensuring that the focal length can be changed reliably. It can be carried out.

In addition, since the switching member is locked by the locking member via the buffer member, the switching member is always biased toward one end of rotation of the switching member due to the elastic restoring force caused by the displacement of the buffer member when it is locked. Therefore, even if there is a connection position shift between the switching member and the pushing member, this can be absorbed. Therefore, the amount of movement of the photographic lens can always be maintained constant, and defocus can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the main parts of a focal length switching device for a focal length switching camera embodying the present invention. FIG. 2 is an external view of the focal length switching camera in the same embodiment. FIG. 3 is a perspective view showing the relationship between the optical system of the focal length switching camera and the TW switching lever. 4 and 5 are plan views for sequentially explaining the operation of the TW switching device. FIG. 6 is a plan view for explaining the interlocking of the first and second TW switching levers. Moving cylinder master lens conversion lens First TW switching lever Second TW switching lever Pushing cam motor TW pend lever 85...Coil spring 90...Lock lever- Fig. 2

Claims (2)

[Claims] (1) The focal point of a camera that selectively transmits the rotational force of the motor to the film feeding system and the focal length switching system via a clutch mechanism to feed the film and switch the focal length of the photographic lens. The distance switching device includes: a pushing member disposed in the focal length switching system and driven by the motor; a buffer member elastically contacting and displaced by a pushing portion of the pushing member; and a buffer member displacing the pushing member. a switching member that is pushed by a pushing part through the switching member to move the photographing lens in the optical axis direction and switch the focal length; and a switching member that is displaced and the switching member is located at one end of the focal length switching A locking member that locks the buffer member by forming a gap between the buffer member and the pushing part when the pushing part is pressed, and the locked state is released by pushing the pushing part again. A camera focal length switching device comprising: (2) The pushing member consists of a pushing cam that rotates half a rotation when switching the focal length, the pushing part consists of a pushing pin eccentrically provided on the pushing cam, and the switching member consists of a switching lever, The buffer member is a buffer lever that is swingably attached to the switching lever and elastically resists the pushing of the push pin by a spring, and the locking member locks the buffer lever. The focal length of the camera according to claim 1, further comprising a locking lever that is engaged with the push pin and released from the locked state by rotation of the push cam after being locked. switching device.