JPH08110454A - Lens barrel having shock absorbing structure - Google Patents

Abstract

PURPOSE: To absorb excessive shock instantaneously given to the front surface of a lens barrel, to prevent the damage or the deformation of a cam groove and a cam shaft or the falling-off of the cam shaft, and to reduce the rate of fault of a camera. CONSTITUTION: In the shock absorbing structure of the lens barrel where plural lens frames are moved in an optical axis direction interlocked with the rotation of cam barrel; a shaft bottom board 11 having the cam shaft 11c slidably fitted in the cam groove 2a formed on the cam barrel 2 is movably fitted in a rear bottom board 10 holding the lens frame 9 and a shutter unit 6, then shock is absorbed by utilizing the spring force of an interlens spring 18 for stabilizing a distance between the lenses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a shock absorbing structure for changing a focal length by moving a photographing optical system in an optical axis direction.

[0002]

2. Description of the Related Art Conventionally, a shock absorbing structure of a lens barrel is shown in FIG.
As shown in FIG. 7, a leaf spring 20 having a set friction force is incorporated in a shaft 19b formed on a gear 19 that interlocks with a gear train (not shown), and a gear 21 is rotatably fitted to the tip of the shaft 19b. At the same time, by press-fitting the hole 21a into the convex portion 20a, the gear 19 and the gear 21 are integrally rotated, and when a force larger than the friction force set in the gear 21 is applied, the gear 21 and the leaf spring 20 are placed between the shaft 19b. Idling at, Gear 19
In addition, a shock absorbing mechanism configured so as not to transmit to a gear train (not shown) was incorporated.

[0003]

However, in the above-mentioned conventional example, when the momentary excessive impact is applied to the entire surface of the lens barrel unit, the gear of the lens barrel drive system is prevented from being damaged.
Since a direct impact is applied to the cam groove formed on the cam barrel and the cam shaft slidably fitted in the cam groove, the cam groove is damaged, the cam shaft is deformed, and the cam shaft falls off. There was a drawback.

In order to solve such a conventional problem, the present invention has an object of the invention according to the first claim to absorb an impact by using an elastic member such as a spring for stabilizing the lens interval. To do. Further, an object of the invention according to the second aspect is to provide a lens barrel having a shock absorbing structure capable of absorbing a shock without increasing an operation load of the lens barrel by providing an elastic member.

[0005]

In order to achieve the above-mentioned object, the invention according to the first aspect is a lens which moves a plurality of lens frames in the optical axis direction in association with the rotation of a rotary cylinder. A shock absorbing structure for a lens barrel, comprising: a supporting member having a cam shaft slidably fitted to the rotating barrel; a holding member holding the supporting member; and the supporting member movably fitted to the holding member. It is characterized in that shock absorbing means for absorbing the shock by combining them is provided.

Further, in the invention according to the second aspect, in a shock absorbing structure of a lens barrel in which a plurality of lens frames are moved in the optical axis direction by interlocking with the rotation of the rotary barrel, it is slidable on the rotary barrel. A supporting member having a cam shaft that fits into the holding member, a holding member that holds the supporting member, and the supporting member that is movably fitted to the holding member, and an elastic member is provided between the supporting member and the holding member. It is characterized by

[0007]

According to the structure described in the first aspect, it is possible to absorb an excessive impact force applied to the front surface of the lens barrel unit by utilizing the elastic member force such as a spring for stabilizing the lens interval. .

According to the second aspect of the invention, the elastic member provided between the support member and the holding member can be used to absorb an excessive impact force applied to the front surface of the lens barrel unit. It is possible to prevent damage to the cam groove and helicoid screw, deformation of the cam shaft, dropping of the cam shaft, and detachment of the helicoid screw without increasing the load of operating the lens barrel.

[0009]

【Example】

(First Embodiment) FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing the structure of the lens barrel unit, and FIG. 2 shows the impact force F on the front surface of the lens barrel unit in the state of FIG.
FIG. 3 is a partial side view showing the configuration of the rear main plate and the shaft main plate which are the main parts of the embodiment, and FIG. 4 is the sectional view of the rear main plate and the shaft main plate which are the main parts of the embodiment. It is a perspective view shown.

1 to 4, reference numeral 1 denotes a fixed cylinder, which is fixed to a camera body (not shown) with a screw, and has a shaft base plate 1 described later.
The three rectilinear holes 1a through which the cam shaft 11c formed in 1 and the rectilinear holes 1b through which the cam shaft 17a formed in the second group lens frame 17 described later penetrate are formed on the circumference. The cam shafts 11c are formed at equal intervals, and the cam shafts 11c move linearly with the rectilinear holes 1a and the cam shafts 17a using the rectilinear holes 1b as guides. A flange portion 1 for receiving a cam cylinder 2 to be described later is provided at a rear end portion.
c and a shaft hole 1d are formed.

Reference numeral 2 denotes a cam cylinder, which is rotatably fitted to the outer circumference of the fixed cylinder 1 and has three cam grooves into which the cam shaft 11c penetrating the rectilinear hole 1a is slidably fitted. 2a and the cam shaft 17a penetrating the rectilinear hole 1b are slidably fitted 3
Book-shaped cam grooves 2b are formed at equal intervals in the circumferential direction, and a gear 2c that meshes with the gear 21 is formed on the outer circumference. The cam barrel 2 is rotated by a known lens barrel driving means, and the cam shaft 11c forms the cam groove 2c.
a, the cam shaft 17a moves back and forth along the cam groove 2b.

A pressing plate 3 is fixed to the tip of the fixed cylinder 1 and holds the cam cylinder 2 and the pressing spring 4. A convex portion 3a for holding the rubber 5 is formed on the inner circumference. Reference numeral 4 denotes a presser spring 4, which presses the cam barrel 2 against the flange portion 1c by a spring force and absorbs the thrust play of the cam barrel 2. Reference numeral 5 denotes rubber, which has a role of closing the gap between the fixed barrel 1 held by the convex portion 3a and the cover 12 that moves in the optical axis direction.

Reference numeral 6 denotes a shutter unit, which has a first-group lens unit 8 (to be described later), a focus driving system and a shutter driving system (not shown) built therein, and shutter blades 7 arranged behind, which are covered by a rear base plate 10 described later. ing.

Reference numeral 8 denotes a first-group lens unit, which is held by a first-group lens frame 9 and is supported by a focus drive system (not shown) so as to be able to extend in front of the camera and to move straight in the extension direction during focusing. ing.

Reference numeral 10 denotes a rear base plate, which is fixed to the shutter unit 6 with screws and supports the shutter unit 6, and guide grooves 10a for guiding a shaft base plate 11, which will be described later, are formed at three positions on the outer periphery at equal intervals. Locking portions 10b that lock the locking claws 11b and guide portions 10c that guide the sliding arms 11a in the circumferential direction are formed on the left and right of the groove 10a.

Reference numeral 11 denotes an axial base plate, which has a role of supporting the rear base plate 10 on the cam cylinder 2, and sliding arms 11a formed on the left and right sides are slidably fitted in the guide grooves 10a to guide the rear base plate 10. Move straight along the portion 10c. A locking claw 11b that locks with the locking portion 10b is formed at the tip of the sliding arm 11a,
It is in contact with the rear base plate 10. Further, a cylindrical cam shaft 11c is formed on the outer circumference, and is slidably fitted into the cam groove 2a through the rectilinear hole 1a.

Reference numeral 12 denotes a cover, which is a first group lens unit 8,
Further, the shutter unit 6 is covered with a screw and is fixed to the base plate 10 after the shutter unit 6, and a barrier 13 for covering the first group lens unit 8 at the time of retracting and a barrier ring 14 for driving the barrier 13 are provided at the tip of the cover 12, and the barrier 13 is further provided. Ring 14
A decorative plate 15 that covers the barrier 13 is fixed.

Reference numeral 16 denotes a second group lens unit, which is held by a second group lens frame 17 and has a cam groove 2 on its outer periphery through a rectilinear hole 1b.
Three cam shafts 17a slidably fitted to b are formed at equal intervals.

Reference numeral 18 denotes an interlens spring, which is a rear base plate 10.
Is provided between the second group lens frame 17 and the second group lens frame 17, and the first group lens unit 8 is pressed forward against the second group lens unit 16 to stabilize the lens interval, and the rear base plate 10 is placed forward of the axial base plate 11. The engaging portion 10b is always pushed into contact with the engaging claw 11b.

Reference numeral 19 denotes a gear, which is interlocked with a well-known lens barrel driving means and has a shaft 19a and a shaft 19b which are vertically formed.
Is rotatably fitted in the shaft hole 1d and the tip of the shaft 19b in the shaft hole 22a, and is supported between the fixed barrel 1 and the gear retainer 22. Reference numeral 20 denotes a leaf spring, which is C-shaped and is incorporated into the shaft 19b by a set friction force to rotate integrally with the gear 19. A convex portion 20a that fits into the gear 21 is formed at the tip. Reference numeral 21 denotes a gear, which is rotatably fitted to the shaft 19b and meshed with the gear portion 2c. The hole 21a formed in the gear 21 is fitted with the convex portion 20a to rotate the gear 19 and the gear 21 integrally. Reference numeral 22 denotes a gear retainer, which is fixed to the fixed cylinder 1 with screws to support the gear 19 and the gear 21. The gear retainer 22 is formed with a hole 22a into which the shaft 19b is rotatably fitted.

In the above-mentioned structure, the cam barrel 11 is fitted in the cam grooves 2a and 2b by rotating the cam barrel 2 in the forward direction through the gears 19 and 21 by the known lens barrel driving means.
The first group lens unit 8 and the second group lens unit 16 move forward while compressing the spring 18 via c and 17a.

Next, the shock absorbing mechanism which is a feature of the present invention will be described. When the front surface of the lens barrel unit is pushed by hand or an impact force F is applied to the decorative plate 15 by colliding with an obstacle such as glass, the shaft base plate 11 having the cam shaft 11c fitted in the cam groove 2a is While the position shown in FIG. 1 is maintained, the rear base plate 10 moves rearward as shown in FIG. 2 while compressing the interlens spring 18 along the sliding arm 11a with respect to the shaft base plate 11, and the impact applied to the front surface of the lens barrel unit. Absorbs.

On the other hand, after absorbing the shock, the inter-lens spring 1
The rear base plate 10 is pushed forward by the spring force of 8 along the sliding arm 11a, the locking portion 10b is locked by the locking claw 11b, and the rear base plate 10 and the first group lens unit 8 are the same as those shown in FIG. Return to the position.

As described above, in the present invention, the shaft base plate 11 having the cam shaft 11c slidably fitted in the cam groove 2a is 1
The spring force of the spring 18 that is movably fitted to the rear base plate 10 that holds the group lens frame 9 and the shutter unit 6 and that stabilizes the lens interval can absorb the shock.

FIGS. 5 to 7 show a second embodiment of the present invention. FIG. 5 is a sectional view showing a lens barrel unit configuration,
FIG. 6 is a sectional view showing a state in which an impact force F is applied to the front surface of the lens barrel unit in the state of FIG. 5, and FIG. 7 shows a configuration of a rear base plate, an axial base plate and an elastic member (absorption spring) which are main parts of the embodiment. It is a partial side view shown.

5 to 7, the same functions as those in the first embodiment are represented by the same numbers. The second embodiment differs from the first embodiment in that an absorbing sprue 23 for absorbing impact is newly provided between the rear base plate 10 and the shaft base plate 11, and the rear base plate 10 has a guide shaft 10d and an axial base plate. The rest is the same as the first embodiment except that the guide shaft 11d is formed on the shaft 11 to guide the absorbing spring 23.

Next, the shock absorbing mechanism which is a feature of the present invention will be described. When the front surface of the lens barrel unit is pushed by hand or an impact force F is applied to the decorative plate 15 by colliding with an obstacle such as glass, the shaft base plate 11 having the cam shaft 11c fitted in the cam groove 2a is shown in FIG. 6, the rear base plate 10 moves rearward with respect to the shaft base plate 11 while compressing the absorption spring 23 and the interlens spring 18 along the sliding arm 11a, and moves to the front of the lens barrel unit. Absorbs the applied shock.

On the other hand, after the impact is absorbed, the rear base plate 10 is pushed forward along the sliding arm 11a by the spring force of the absorbing spring 23 and the interlens spring 18, and the locking portion 10b.
Is locked by the locking claw 11b, and the rear base plate 10 and the first group lens unit 8 are returned to the original positions shown in FIG.

As described above, in the present invention, the shaft base plate 11 having the cam shaft 11c slidably fitted in the cam groove 2a is 1
Rear base plate 10 that holds the group lens frame and the shutter unit
By absorbing the shock by using the spring force of the spring 23 without increasing the load of operating the lens barrel, the absorption spring 23 is fitted between the shaft base plate 11 and the rear base plate 10 so as to be movable. You can

FIG. 8 shows a third embodiment of the present invention. FIG. 8 is a sectional view showing the configuration of the lens barrel unit.

In FIG. 8, the same functions as those in the first embodiment are represented by the same numbers. The third embodiment differs from the first embodiment in that a shaft base plate 11 having three cam shafts 11c slidably fitted in the cam grooves 2a has a cylindrical shape and a sliding arm is provided on the entire outer circumference. 11a and a locking claw 11b are formed on the tip thereof, and the locking part 10b to which the locking claw 11b locks is formed on the rear base plate 1.
It is all the same as the first embodiment except that it is formed on the entire inner circumference of the rear end portion of 0. The operation and mechanism are the first
The description is omitted because it is similar to the embodiment described above.

As described above, according to the present invention, the shaft base plate 11 having the cam shaft 11c is integrated to reduce the number of parts and reduce the cost, and the spring force of the inter-lens spring 18 for stabilizing the lens interval is provided. It can be used to absorb shock.

[0033]

As described above, according to the first aspect of the invention, a supporting member having a cam shaft slidably fitted to a rotary cylinder for moving a plurality of lens frames in the optical axis direction,
A holding member that holds the support member, and a support member that is movably fitted to the holding member and absorbs an impact, thereby absorbing an excessive impact force that is instantaneously applied to the front surface of the lens barrel unit. It is possible to prevent damage to the cam groove or helicoid, deformation of the cam shaft, dropping of the cam shaft, or removal of the helicoid screw, and reduce the failure rate of the lens barrel or the camera having it. .

According to the second aspect of the invention, a supporting member having a cam shaft slidably fitted in a rotary cylinder for moving the plurality of lens frames in the optical axis direction, and the supporting member are held. A holding member and the supporting member are movably fitted to the holding member, and an elastic member is provided between the supporting member and the holding member to absorb the shock by utilizing the elastic force of the elastic member. It is possible to absorb an excessively large impact force that is momentarily applied to the front of the cylinder unit, damaging the cam groove and helicoid,
Further, it is possible to prevent the cam shaft from being deformed, the cam shaft from falling off, or the helicoid screw from coming off, and it is possible to reduce the failure rate of the lens barrel or the camera having the lens barrel.

[Brief description of drawings]

FIG. 1 is a sectional view showing a lens barrel unit configuration according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which an impact force F is applied to the front surface of the lens barrel unit in the state of FIG. 1 in the first embodiment of the present invention.

FIG. 3 is a partial side view showing a configuration of a rear base plate and an axial base plate which are main parts in the first embodiment of the present invention.

FIG. 4 is a perspective view showing the configuration of the main part of the first embodiment of the present invention.

FIG. 5 is a sectional view showing the configuration of a lens barrel unit according to the second embodiment of the present invention.

FIG. 6 is a sectional view showing a state in which an impact force F is applied to the front surface of the lens barrel unit in the state of FIG. 5 in the second embodiment of the present invention.

FIG. 7 is a partial side view showing configurations of a rear base plate, an axial base plate, and an elastic member, which are main parts in a second embodiment of the present invention.

FIG. 8 is a sectional view showing the configuration of a lens barrel unit according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of a lens barrel unit including a gear unit that absorbs an impact in a conventional example.

[Explanation of symbols]

 1 Fixed barrel 2 Cam barrels 2a, 2b Cam grooves 2c Gear 6 Shutter unit 8 1st group lens frame 9 1st group lens unit 10 Rear bottom plate 10a Guide groove 10b Locking part 10c Guide part 10d, 11d Guide shaft 11 Shaft base plate 11b Locking Claws 11c, 17a Cam shaft 12 Cover 15 Temporary plate 16 Second group lens unit 17 Second group lens frame 18 Inter-lens spring 19, 21 Gear 20 Leaf spring 22 Gear retainer 23 Absorption spring

Claims (4)

[Claims] 1. A shock absorbing structure for a lens barrel that moves a plurality of lens frames in the optical axis direction in association with the rotation of a rotary barrel, and has a cam shaft slidably fitted in the rotary barrel. A shock absorbing structure characterized by comprising: a support member; a holding member for holding the support member; and a shock absorbing means for absorbing the shock while movably fitting the support member to the holding member. Lens barrel. 2. A shock absorbing structure for a lens barrel that moves a plurality of lens frames in the optical axis direction in conjunction with the rotation of a rotary barrel, and has a cam shaft slidably fitted in the rotary barrel. A shock absorbing device, comprising: a supporting member; a holding member for holding the supporting member; and the supporting member movably fitted to the holding member, and an elastic member provided between the supporting member and the holding member. A lens barrel having a structure. 3. The shock absorbing device according to claim 2, wherein the supporting member is movably fitted to a lens frame holding a lens unit, and an elastic member is provided between the supporting member and the lens frame. A lens barrel having a structure. 4. The lens barrel having a shock absorbing structure according to claim 1, 2, or 3, wherein the rotating barrel and the supporting member have a helicoid screw.