JP4605831B2 - Zoom finder device - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a zoom finder device for a zoom compact camera.
[0002]
[Prior art and its problems]
The zoom compact camera has a zoom finder device that changes the field of view in conjunction with a zoom photographing lens. This zoom finder device has a basic configuration in which a movable zoom lens that is supported so as to be movable in the optical axis direction is moved to a predetermined position by a cam member that is driven in conjunction with the zoom photographing lens.
[0003]
Among these, the zoom finder device using the cylindrical cam member as the cam member conventionally forms the cylindrical cam directly on the drive shaft that is rotationally driven in conjunction with the zoom photographing lens. For this reason, when the focal lengths (magnification) of the zoom photographing lens and the zoom finder are linked (aligned), the rotational phase of the cylindrical cam member must be strictly adjusted, and there is a problem that the assembling workability is very poor. It was.
[0004]
OBJECT OF THE INVENTION
SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom finder apparatus that can be driven using a cylindrical cam and that can easily secure the interlocking relationship with the zoom photographing lens side without performing phase alignment during assembly.
[0005]
Summary of the Invention
The present invention relates to a zoom finder device that is driven in conjunction with a zoom photographing lens, and a pair of movable variable magnification lenses that are supported so as to be movable in the optical axis direction; a drive shaft that is rotationally driven in conjunction with the zoom photographing lens. A cylindrical cam member having a pair of cylindrical cam surfaces that are fitted to the drive shaft so as to be rotatable relative to each other and change a position in the optical axis direction of the pair of movable zoom lenses; and the drive shaft and the cylindrical cam member; normally rotates integrally without causing relative rotation, friction mechanism that allows relative rotation when the load exceeding a predetermined value is applied; equipped with, to the cylindrical cam member, the pair of cylindrical cam surface and A single stopper member for restricting the rotation range of the cylindrical cam member is provided independently of the follower protrusions on the pair of movable variable magnification lenses that contact the pair of cylindrical cam surfaces . Neighborhood fine The frame body is formed a pair of positioning surfaces for regulating both rotation end of the cylindrical cam member directly abuts to the single stopper member of the cylindrical cam member, said friction mechanism, said single cylindrical cam member When the drive shaft is rotationally driven in the tele direction while the stopper member is not in contact with the positioning surface, the drive shaft and the cylindrical cam member are rotated together, and the zoom finder optical system is moved to the tele end position. In the state where the single stopper member of the rear cylindrical cam member is in contact with one of the pair of positioning surfaces , the drive shaft and the cylindrical cam member are allowed to rotate relative to each other.
[0006]
According to this zoom finder device, assembling is performed without worrying about the phase of the cylindrical cam member, and after completion of the assembly, the phase adjustment is performed by rotating the cylindrical cam member relative to the drive shaft via the friction mechanism. Since it can be performed, assemblability is improved.
[0007]
According to this zoom finder device , the phase alignment can be achieved by first rotating the drive shaft forward to bring the stopper member into contact with one positioning surface, and then rotating it reversely to bring the stopper member into contact with the other positioning surface. finish.
[0008]
The friction mechanism includes, for example, a friction surface formed on each of the drive shaft and the cylindrical cam member, and a spring member that moves and urges at least one of the drive shaft and the cylindrical cam member in a direction in which the friction surfaces contact each other. It can consist of.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
A zoom compact camera 10 shown in FIG. 1 has a zoom photographing lens 11 in the center, and a zoom finder device 12 in the upper part thereof. The rotation of the drive motor 13 at the lower left of the front is transmitted to the zoom photographing lens 11 through the gear train 14, and further the drive shaft gear of the zoom finder device 12 through the outer gear 15 and the transmission gears 16, 17 of the zoom photographing lens 11. 18 is transmitted.
[0010]
As shown in FIGS. 2 and 3, the drive shaft gear 18 has a drive shaft 19 extending coaxially in a direction parallel to the optical axis of the zoom finder device 12, and can be rotated relative to the drive shaft 19. A cylindrical cam member 20 is fitted. The cylindrical cam member 20 has a pair of cylindrical cam surfaces 21 and 22, and the cylindrical cam surfaces 21 and 22 are follower protrusions that are integrally provided on the support frame of the movable zoom lenses 23 and 24 of the zoom finder device 12. Engages with 23P and 24P. The movable variable lenses 23 and 24 are guided straight in the optical axis direction by a guide rod 29 (FIG. 3). The movable zoom lenses 23 and 24 are urged to move so that the follower projections 23P and 24P abut against the cylindrical cam surfaces 21 and 22 by a tension spring 26 stretched between them. The zoom finder device 12 is composed of the movable variable lenses 23 and 24 and a fixed lens group (not shown), and when the movable variable lenses 23 and 24 move along a predetermined locus, the magnification changes.
[0011]
A friction plate 26 is fixed to the drive shaft 19 via a lock washer 25. On the other hand, a friction projection 27 that engages with the friction plate 26 is integrally provided on the cylindrical cam member 20. The friction plate 26 and the friction projection 27 are always in frictional contact with each other by a compression spring 28 that moves and urges the cylindrical cam member 20 in the axial direction. The force of the compression spring 28 is such that when the drive shaft 19 is driven to rotate, the cylindrical cam member 20 is normally rotated together with the drive shaft 19 via the friction plate 26 and the friction projection 27 to cause the cylindrical cam surface 21, 22, when the movable zoom lenses 23 and 24 are moved, and when the rotation of the cylindrical cam member 20 is mechanically braked, the friction projection 27 is rotated relative to the friction plate 26, and the cylindrical cam is rotated. The drive shaft 19 is set to rotate relative to the member 20 (idle).
[0012]
The cylindrical cam member 20 is integrally formed with a stopper member 30 that regulates the rotation range. On the other hand, the finder frame (fixed member) 31 in the vicinity of the cylindrical cam member 20 has a tele position restricting surface 32T that contacts the stopper member 30 in accordance with the rotational direction of the cylindrical cam member 20 and a storage position restricting member. It has a surface 32S. The positions of the stopper protrusion 30, the tele position restricting surface 32T, and the storage position restricting surface 32S are determined as follows.
[0013]
In assembling the zoom finder device described above, the follower protrusion 23P of the movable zoom lens 23 is brought into contact with the cylindrical cam surface 21 in a state where the drive shaft 19 and the cylindrical cam member 20 are frictionally engaged by the compression spring 28. The follower projection 24P of the movable zoom lens 24 is brought into contact with the cylindrical cam surface 22. The engagement between the cylindrical cam surfaces 21 and 22 and the follower protrusions 23P and 24P is ensured by a tension spring (not shown). In this temporary assembly, it is not necessary to adjust the phase of the cylindrical cam member 20, and naturally, the magnification of the zoom finder device 12 including the movable variable lenses 23 and 24 corresponds to the focal length of the zoom photographing lens 11. Absent.
[0014]
In this temporarily assembled state, when the drive motor 13 is driven in the tele direction, for example, the zoom photographing lens 11 is driven through the gear train 14 and the focal length thereof is in the tele end state. In addition, the rotation of the drive motor 13 causes the drive shaft 19 to rotate in the tele direction via the transmission gears 16 and 17 and the drive shaft gear 18, before and after the zoom photographing lens 11 enters the tele end state, The stopper member 30 of the cylindrical cam member 20 that rotates together with the drive shaft 19 abuts on the tele position restricting surface 32T of the finder frame 31. At this time, due to the cylindrical cam surfaces 21 and 22 of the cylindrical cam member 20, the distance between the movable zoom lenses 23 and 24 is the distance at the magnification corresponding to the focal length of the telephoto end of the zoom photographing lens 11. However, it is normal that the timing at which the zoom photographing lens 11 reaches the tele end and the timing at which the stopper member 30 abuts on the tele position restricting surface 32T are different, and the movable zoom lenses 23 and 24 are correct with respect to other fixed lenses. There is no guarantee that it is in a relative position. After the stopper member 30 comes into contact with the tele position restricting surface 32T, the drive shaft 19 idles with respect to the cylindrical cam member 20.
[0015]
In this way, when it is confirmed that the zoom photographing lens 11 has reached the tele end and the stopper member 30 has come into contact with the tele position regulating surface 32T, the direction in which the drive motor 13 is reversed and the zoom photographing lens 11 is housed is now. Turn to. Then, the zoom photographing lens 11 is brought into a retracted state via the gear train 14. A stopper member 30 of the cylindrical cam member 20 that rotates together with the drive shaft 19 via the transmission gears 16 and 17 and the drive shaft gear 18 before and after the zoom photographing lens 11 is in the retracted state is a finder frame. 31 abuts on the storage position regulating surface 32S. At this time, not only the distance between the movable zoom lenses 23 and 24 but also the relative position with other fixed lenses is in a correct relationship, and the interlocking adjustment between the zoom photographing lens 11 and the zoom finder device 12 is completed.
[0016]
In the above embodiments, the zoom photographing lens 11 has been described as having a telephoto end and a storage end. However, the same adjustment can be made when the wide end is used instead of the storage end. That is, the same adjustment is possible when the zoom lens has no storage position (when the wide end is the storage end).
[0017]
【The invention's effect】
According to the present invention, in a zoom finder device driven using a cylindrical cam, it is possible to easily ensure the interlocking relationship with the zoom photographing lens side without performing phase alignment at the time of assembly.
[Brief description of the drawings]
FIG. 1 is a front view of a zoom compact camera having a zoom finder device according to the present invention.
FIG. 2 is a side cross-sectional view of a main part along an optical axis of a zoom finder device, showing an example of a drive shaft, a cylindrical cam member, and a friction mechanism.
FIG. 3 is a front view of FIG. 2 as viewed from the right side.
FIG. 4 is a perspective view showing an example of a relationship between a stopper projection of a cylindrical cam member and a positioning surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Zoom compact camera 11 Zoom imaging lens 12 Zoom finder apparatus 18 Drive shaft gear 19 Drive shaft 20 Cylindrical cam member 21 22 Cylindrical cam surface 23 24 Movable variable magnification lens 26 Friction plate 27 Friction protrusion 28 Compression spring 30 Stopper member 31 Finder frame body (Fixing member)
32T Tele-position restriction surface 32S Storage position restriction surface

Claims (2)

In the zoom finder device driven in conjunction with the zoom shooting lens,
A pair of movable zoom lenses supported so as to be movable in the direction of the optical axis;
A drive shaft that is rotationally driven in conjunction with the zoom photographing lens;
A cylindrical cam member fitted to the drive shaft so as to be relatively rotatable and having a pair of cylindrical cam surfaces for changing the position of the pair of movable zoom lenses in the optical axis direction; and the drive shaft and the cylindrical cam member are always connected Comprises a friction mechanism that rotates together without causing relative rotation and permits relative rotation when a load of a certain value or more is applied;
The rotational range of the cylindrical cam member is regulated independently from the pair of cylindrical cam surfaces and the follower protrusions on the pair of movable variable magnification lenses that are in contact with the pair of cylindrical cam surfaces. A single stopper member is provided,
A pair of positioning surfaces that directly contact the single stopper member of the cylindrical cam member and restrict both rotational ends of the cylindrical cam member are formed on the finder frame near the cylindrical cam member.
The friction mechanism rotates the drive shaft and the cylindrical cam member integrally when the drive shaft is rotated in the tele direction in a state where the single stopper member of the cylindrical cam member is not in contact with the positioning surface. When the single stopper member of the cylindrical cam member is in contact with one of the pair of positioning surfaces after the zoom finder optical system is moved to the tele end position , the drive shaft and the cylindrical cam member are relatively rotated. forgive,
A zoom finder device characterized by that. The zoom finder device according to claim 1.
The friction mechanism includes a friction surface formed on each of the drive shaft and the cylindrical cam member, and a spring member that moves and urges at least one of the drive shaft and the cylindrical cam member in a direction in which the friction surfaces contact each other. Zoom finder device.

Images