JP2601864Y2 - Rear cap for interchangeable lens - Google Patents

Description

[Detailed description of the invention]

[0001]

INVENTION The present invention relates, against the mounting portion at the rear open end of the interchangeable camera lens barrel, the present invention relates a plastic cap for lens protection be deposited by a bayonet coupling, more specifically, It relates to the improvement of the bayonet coupling mechanism.

[0002]

BACKGROUND OF THE INVENTION A bayonet coupling, as shown in FIG. 6, one of the structural parts to be secured together, after forme because fitting the first <br/> other part (the insertion direction C), inserted This is an easily disassembled connection that is rotated in the direction perpendicular to the direction (rotation direction D) and assembled. That is, bayonet projections 10 provided at three positions on the circumference on equidistant positions around the periphery the inner wall 102 of the rear cap 100 (shown only one location in the drawing)
4 is the bayonet claw 108,..., 1 on the interchangeable lens 106 side.
In general, it is fixed to the lens mount unit 110 by engaging with the lens mount unit 08. Bayonet projections 104, arrows next to the insertion direction indicated by the corresponding <br/> notch 114 in the arrow C D
The inclined surface 116 of the bayonet projection 104 is engaged with the bayonet claw 108 in the rotation direction indicated by. At this time, the outer wall rim surface 112 of the rear cap 100 so adapted to slide in crimped to mount 110,
A wedge effect occurs on the inclined surface 116. Result of forced line of cormorants rotating the wedging action, the end 12 of the bayonet claws 108
In position 2 is abuts the detent 118, the fixed effect of friction occurs. In such a bayonet connection of the rear cap , in the first fitting, three bayonet
It is required that the projections 104 be simultaneously aligned with the respective notches 114 .

[0003]

While natural The present invention is to provide a, when tightening the mount portion of the rear cap because each bayonet there is a dimension error, first use is strictly a fit because fitted, is difficult to turn to the end of the rotation In many cases, the bayonet protrusions on the rear cap side were scraped off by the bayonet claws on the interchangeable lens side by forcibly tightening. As a result, there is a disadvantage that the shavings contaminate the lens, and as the number of times of use increases, the tightening becomes loose, so that the connection is loosened naturally, and the rear cap accidentally falls off due to vibration or the like.

An object of the present invention is to provide a rear cap in which the rear cap can be easily turned to the end of rotation, and the bayonet projections on the rear cap are not cut off by the bayonet claws on the interchangeable lens. It is in.

[0005]

The rear cap according to the present invention is made of plastic, and the bayonet projection provided on the inner peripheral wall of the rear cap can be elastically displaced independently of the inner peripheral wall. provided that includes Ri switching the peripheral inner wall in the vicinity of the protruding portion.

[0006] More preferably, I Wataru the bayonet protrusion entire length, spaced apart from the peripheral edge the inner wall of the cap, so that the elastic beams supported at both ends, the longitudinal direction of the bayonet projections portions included Ri the switching Along the peripheral edge inner wall located on the opposite side of the opening edge of the rear cap so as to penetrate the wall thickness, so that the cut-up portion extends slightly longer than the end of the bayonet projection portion. peripheral edge or rim inner wall portion including the bayonet projections portion, spaced from the peripheral edge the inner wall of the cap I Wataru the entire length, so as to constitute the elastic beam of the one end support, surrounding the bayonet projections moiety included Ri the switching against the inner wall portion, in a manner penetrating the wall thickness provided in a U-shape. Furthermore, smooth gradients along a peripheral inner wall portion including the bayonet protrusion configured to elastic beam of the one end support, towards the free end from the fixed end of the elastic beam, the vortex lines of reduction of the internal diameter of the cap Surface so as to be in sliding contact with the outer periphery of the bayonet claw on the interchangeable lens side.

[0007]

[Action] In one configured in this way, around the portion of the bayonet protruding portion of the rear cap, by providing an inclusive Ri switching penetrating a peripheral inner wall, and the peripheral inner wall and continuously provided in the conventional art and it should bayonet protrusions portion will form a separate elastic beam. In this, the bayonet claw bayonet protruding portion of the rear cap on occlusion of the interchangeable lens side, it is possible to elastically displaced. Therefore, combined bite bayonet the interchangeable lens bayonet claw of rear cap, bayonet protruding portion of the rear cap pressed against the bayonet claws of the interchangeable lens is elastically bent, to escape deformed, the interchangeable lens While it can be prevented from being scraped by bayonet claws,
To act as a loosening stop.

[0008] words words, bayonet protruding portion of the rear cap is resiliently biased, only act to retain the bayonet claws and pressure of the interchangeable lens, the resistance acting obstacles manner as a rigid body The rear cap can be turned without difficulty until the end of rotation. Moreover, this deformation, since it is suppressed obtain it in the elastic limit, the increased frequency of use, the clamping force of the loosening stopper is not lowered.

[0009] Here, for the bayonet protrusions portion provided in the vicinity of the opening edge portion of the rear cap, in order to I a reasonably lines the deformation within the elastic limit, and along a bayonet projection portion, a rear the included Ri switching penetrating a peripheral inner wall located on the opposite side of the opening edge portion of the cap is provided, a ramped portion, extend further only slightly longer than the both end portions of the bayonet protrusion, rear cap including a bayonet protrusion peripheral inner wall of, so as to form an elastic beams supported at both ends. With this configuration , even if the amount of deformation due to a dimensional error becomes somewhat large, the deformation of the peripheral inner wall of the rear cap including the bayonet protrusion acts so as to be able to cope within the elastic limit.

Further, for the bayonet protrusions portion located away from the opening edge of the rear cap, in order to I a reasonably line deformation within the elastic limit, around the bayonet protrusion, through a peripheral inner wall by providing a switching inclusive Ri U-shaped to the peripheral inner wall of the rear cap including bayonet protrusions portion, so as to form a resilient beam at one end support. With this configuration , even if the amount of deformation is quite large ,
The deformation of the inner peripheral wall of the rear cap including the bayonet protrusion acts so as to be able to cope within the elastic limit.

[0011] While natural and to be able to accommodate large deformation amount, when the small amount of deformation, elastic urging force for pressing is deteriorated. Therefore, the bayonet protrusion and the peripheral inner wall of the integral forming the elastic beam of the one end support, towards the free end from the fixed end of the elastic beam, a smooth slope surface along the vortex lines of reduction of the internal diameter of the cap Is established,
The outer periphery of the bayonet claw on the interchangeable lens side should be elastically slidably contacted. This fact, together with the large deformation of the elastic beam by one end support, since a large elastic biasing force can be obtained to the pressure contact in the elastic limit, can act as a high loosening stop the further degree of freedom.

[0012]

DETAILED DESCRIPTION FIG. 1 is mounted a first embodiment according to the present invention
It is a perspective view shown with the mount part of the lens which should be performed . 1
1 is a rear cap, at equal intervals at three positions on the circle circumference on the peripheral inner wall 13 (shown only one location in the drawing), the bayonet projections 1
5 are provided. This and along a longitudinal direction of the bayonet projections 15, and the opening edge portion of the rear cap 11, provided by penetrating the Switching Operation included 17 on the peripheral inner wall 13 located on the opposite side,
The cut-up portion is extended slightly more than both ends of the bayonet projection portion, and elastic beams 19 supported at both ends are provided on the inner peripheral wall 13 of the rear cap 11 including the bayonet projection 15.
To form FIG. 4 is an exploded view showing a preferred shape of the elastic beam 19. In this case , in order to impart toughness , elastic beams 19
The width of the support portions at both ends is reduced. Meanwhile, the facing Switching Operation included 17 side interchangeable lens 21 side of the bayonet claws 23 of the bayonet projections 15, ..., 23 and occlusion sliding surface 27 side of the slope surface 29 I over a period of about half of its length It has become. Reference numeral 31 denotes a rotation stopper.

[0013] When fixing the rear cap 11 to the mounting portion 33 of the interchangeable lens 21, bayonet projections 15, through the corresponding notches 35, the insertion direction indicated by arrow A
Inclusive because fitting, the outer wall rim surface 37 of the rear cap 11 crimped to mount 33. Then , when rotated in the direction shown by the arrow B, the outer wall rim surface 37 of the rear cap 11 is pressed against the mount portion 33 and slid, while the bayonet protrusion 15
When the inclined surface 29 is engaged with the bayonet claw 23, the inclined surface 29 has a wedge action. This rotation to force the wedging action line sparse, and the elastic beams 19 elastically deformed, the sliding surface 27 of the bayonet projections 15, pressed against reasonably with a suitable urging force to the bayonet claws 23. When the end portion 39 of the bayonet claws 23 reaches the position where the abutment to the rotation stopper 31, the sliding surface 27 of the bayonet claws 23 of the bayonet projections 15, rim surface 37 the cooperation that crimped to mount 33 , it acts as a loosening stop. Elastic deformation of the elastic beam 19, as cracking <br/> rows within the elastic limit, so that no action of loosening stopped with permanent deformation is diminished.

FIG. 2 shows a rear cap 11a according to a second embodiment of the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals. In the present embodiment, Switching Operation inclusive 17a provided by penetrating the peripheral inner wall 13 surrounds the bayonet projections 15 on the U-shaped, except for forming the elastic beam 41 at one end support, as in the first embodiment It is. In this case, the tolerance for the dimensional error of the connection portion is larger than in the case of the first embodiment.

[0015] Figure 3 is disclosed as a modification of the rear cap 11a of the second embodiment according to the present invention, showing a rear cap 11b of a third embodiment. In the figure, the same reference numerals are used for those common to FIGS. 1 and 2. In this embodiment, the elastic beam 41a supported at one end includes the peripheral inner wall 13 included in the elastic beam 41 supported at one end in the second embodiment.
Of the surface of the one part, towards the free end from the fixed end, and a smooth slope surface along the vortex lines of reduction of the internal diameter of the cap, the outer periphery of the interchangeable lens side of the bayonet claws 23, sliding contact with the elastic contact This is the same as the second embodiment except for the above. FIG.
Is a plan view of the rear cap 11b according to the third embodiment of the present invention as viewed from the opening side, and a smooth gradient surface along a vortex line provided in the elastic beam 41a supported at one end is indicated by a broken line.
The bayonet protrusion 15 of such a rear cap 11b
And when bound to the interchangeable lens side of the bayonet claws 23 (see FIG. 1), when the rotation of the rear cap 11b in the direction of arrow B (see FIG. 1), the outer periphery of the bayonet claws 23, elastic beam 41a shown in this broken line Is elastically expanded in the direction indicated by the arrow E. In this case, since the loosening stopper action is also added from the surroundings, bayonet coupling, more dimensionally high degree of freedom, also binding becomes stable.

The present invention is not intended to be limited to the above embodiments, the invention set forth in the scope of claims as Japanese
Changes can be made in details without departing from the spirit .

[0017]

As has been described above devised], bayonet projections of the rear cap replacement lens according to the present invention is, since the bayonet claws and elastically coupling the interchangeable lens to form an elastic beam, those or the mounting, always on that can be reasonably rotation, because there is the action of loosening stop, a fear that the rear cap from falling off in the secular nature of the slack is no Kunar. Moreover, the bayonet projections of the rear cap, since there be scraped bayonet claws of the interchangeable lens, the swarf chips, lenses and it is no no longer contaminated, the original purpose of the lens protection can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a bayonet connection between a rear cap and an interchangeable lens according to the present invention is released.

FIG. 2 shows a second embodiment of the rear cap according to the present invention .
A bayonet projections kicking a perspective view showing the relationship between the notch.

FIG. 3 shows a third embodiment of the rear cap according to the present invention .
A bayonet projections kicking a perspective view showing the relationship between the notch.

FIG. 4 shows a first embodiment of a rear cap according to the present invention .
A bayonet projections kicking a development view illustrating the relationship between the notch.

FIG. 5 shows a rear cap according to a third embodiment of the present invention .
Kicking is a plan view as viewed from the opening side for explaining the action of the elastic beams of one end support.

FIG. 6 is a perspective view showing a state where a bayonet connection between a rear cap and an interchangeable lens according to a conventional example is released.

[Explanation of symbols]

11 rear cap 13 peripheral inner wall 15 bayonet projections 17 Switching Operation included 19 resilient beams 21 interchangeable lens 23 bayonet claws

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-161951 (JP, A) JP-A-3-60194 (JP, A) Fully open 50-150333 (JP, U) Fully open Showa 54- 59349 (JP, U) Japanese Utility Model Showa 56-60927 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03B 17/14

Claims (3)

(57) [Scope of request for utility model registration] 1. A rear cap for protecting a plastic lens, which is fixed to a mount portion of an interchangeable lens by bayonet coupling, wherein a bayonet projection provided on an inner peripheral wall of the rear cap is provided with a peripheral edge of the cap over the entire length. Separate from the inner wall and penetrate the wall thickness through the peripheral inner wall located on the opposite side to the opening edge of the rear cap along the longitudinal direction of the bayonet projection so as to form an elastic beam supported at both ends. A rear cap for an interchangeable lens, wherein the cut-out portion extends slightly longer than the end of the bayonet protrusion. 2. A rear cap for protecting a plastic lens fixed to a mount portion of an interchangeable lens by bayonet coupling, wherein a peripheral inner wall portion including a bayonet protrusion provided on a peripheral inner wall of the rear cap has an entire length. A rear cap for an interchangeable lens in which the notch is formed in a U-shape so as to form a notch in the peripheral inner wall portion surrounding the bayonet projection portion so as to form an elastic beam supported at one end. . 3. A rear cap for protecting a plastic lens, which is fixed to a mount part of an interchangeable lens by bayonet coupling, comprising a bayonet protrusion on an inner peripheral wall of the rear cap, and an elastic beam supported at one end. From the fixed end side of the elastic beam toward the free end, a smooth line along a vortex line that reduces the inner diameter of the cap is formed such that the inner peripheral wall portion including the bayonet projection portion is in sliding contact with the outer periphery of the bayonet claw on the interchangeable lens side. Rear cap for interchangeable lenses with a gentle slope.