JPS6211330B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bayonet device for optical equipment such as the lens barrel and intermediate tube of a single-lens reflex camera, and the interchangeable lens barrel of an enlarger.

Attach the interchangeable lens to the bayonet part on the camera side.
The bayonet device for detachment requires a signal member that transmits signals such as exposure control to the camera side and lens side, and an interlocking member for information transmission to be held in a predetermined position on the lens side, so it is necessary to tighten the fitting. accuracy·
Fitting strength is required. Furthermore, in terms of structure, it is necessary to provide claws and notches to fit with the camera side bayonet part, as well as dimensional constraints to prevent wobbling in the optical axis direction of the lens and camera when attached to the camera. As a result, the structure and shape have become extremely complex, and many processing steps are required to finish the desired shape from the workpiece. In addition, conventional bayonet devices are made of stainless steel due to mechanical performance and strength.
Since materials such as steel are used, the cost of materials is relatively high and materials with poor workability are cut into complex structures and shapes, making it difficult to reduce costs. In addition, in conventional bayonet devices, the bayonet member on the lens barrel side that is bayonet-coupled with the camera-side bayonet member has a complicated structure and shape, and the connecting surface with the bayonet member and the optical axis of the lens and camera when installed are complicated. It is necessary to achieve dimensional accuracy of the machined surface to control the dimension in the direction, which requires a large number of man-hours, making it difficult to reduce costs.

The present invention makes it possible to change the processing method and material of the tightening member by configuring the bayonet member in a bayonet device with a plurality of members, thereby significantly reducing the number of processing steps and the number of processing steps, and reducing the number of processing steps required by conventional cutting processing. The purpose of the present invention is to provide a bayonet device that can obtain accuracy and strength equivalent to or higher than that of the conventional bayonet device.

Furthermore, in conventional bayonet devices, the position of the lens and camera in the optical axis direction is generally regulated by the elastic force of a spring provided on the camera side. This spring in the thrust direction causes the lens to tilt (tilt from a predetermined angle between the optical axis and the film exposure surface or between the optical axis and the finder optical system).
It also has the role of absorbing looseness when the lens and camera are fitted together, but in order to minimize the looseness of the lens falling down, the spring force of the spring in the thrust direction must be strong. This results in a decrease in operability when the lens is attached.

Furthermore, there is play within the accuracy range in the radial direction of the lens and camera due to their fitting relationship. It is better to have some play in order to improve operability when the lens is attached, but due to this play, the weight of the lens barrel causes a misalignment between the lens optical axis and the camera's lens attachment center position, and the lens and camera As a result, the engagement position of the signal member for exposure control becomes misaligned, making it impossible to receive correct signals between the lens and camera. In order to solve the above-mentioned drawbacks of the conventional bayonet device, the present invention disposes a spring member having elastic properties in the thrust direction and the radial direction in the bayonet member to eliminate misalignment of the optical axis between the lens and the camera. The present invention provides a bayonet device for a lens barrel that can improve operability, especially sensory performance. Furthermore, the present invention provides a bayonet device in which the spring member can be disposed in a part of the bayonet member constituted by the plurality of members described above.

Embodiments of the present invention will be described in detail below with illustrations.

1 to 5 show specific examples in which the mounting and tightening device according to the present invention is applied between an interchangeable lens and a camera to which the interchangeable lens is mounted.

In FIG. 1, 1 is a lens barrel body formed in a ring shape and has a threaded surface for distance adjustment (not shown) on the inner surface of its tip; 2 is a distance adjustment ring; It is provided integrally with an intermediate helicoid ring (not shown) that meshes with the screwing surface of the lens 1, and allows a lens (not shown) to advance and retreat using a known helicoid screw. 4 indicates a bayonet mount retaining ring integrally fixed to the rear end of the lens barrel body 1;
An engraved portion 4a is provided on the outer periphery of the ring to indicate a reference mounting position during mounting. Reference numeral 5 denotes a known aperture ring which is rotatably fitted into a concave ring formed between the lens barrel body 1 and the retaining ring 4 and is interlocked with an aperture device built into the lens barrel body 1, and 6 is a retainer. A bayonet member fitted into the rear opening step of the ring 4 performs a tightening operation against a camera-side bayonet pawl when a lens is attached to a camera body, which will be described later. Reference numeral 16 denotes a spring member fixed to the bayonet member, the details of which will be described later.

The bayonet member 6 includes a first tightening ring 6A (FIG. 2) and a second tightening ring 6 formed into a brim shape and made of uniformly thick material as shown in FIGS. 2 and 3.
B (Fig. 3) is joined by means such as welding or gluing, and as shown in Fig. 1, the retaining ring 4 is prevented from coming off by the bent part of the end of the retaining ring 4, and the retaining ring 4 is secured by a screw 7 or a caulking material. be fixed integrally against the Reference numeral 8 denotes a mount member which is rotatably fitted into a concave ring between the retaining ring 4 and the bayonet member 6, and whose rear part is formed into a cylindrical shape and has a reference fitting diameter portion 8a. 10
A positioning pin is set up on the mount reference position surface of the mount member 8 and is fitted into a position regulating groove formed in the camera side bayonet portion to engage the mount member 8.

A tightening ring 6A constituting the bayonet member 6,
6B has bayonet claws 6A ₁ and 6B ₁ spaced apart by about 120° as shown in FIGS. 2 and 3.
6A ₃ and 6B ₃ are protrusions integrally formed on each of the tightening rings A and B, and are provided at positions facing the positioning pins 10, so that when the lens is removed from the camera, it is attached to the fixed part side of the lens barrel. It has a function of allowing the lens to be removed from the camera when the mount members come to the correct rotational position relative to each other in the rotational relationship.

Next, the bayonet member 6 will be explained in detail.

As mentioned above, the bayonet member is the tightening ring A.
(Fig. 2), a tightening ring B (Fig. 3), and a spring member (Fig. 4).

The tightening ring A is composed of a flange portion 6A ₄ that is fitted and fixed into the holding ring 4 of the lens barrel, a plurality of claw portions 6A ₁ , and a notch portion 6A ₂ .

The tightening ring B is dimensioned so that it can be joined to the inside of the aforementioned tightening ring A, and the flange _6B4 and the tightening ring A are connected to each other.
The same number of claws/notches 6B ₁ and notches 6B ₂
has. When the circumferential length of the claw portion _6B1 of tightening ring B is shorter than the circumferential length of the claw portion of tightening ring A, and rings A and B are joined. Claw portion 6 at the overlap between tightening rings A and B
A ₁ and 6B ₁ constitute a bayonet pawl, and the pawl portion 6A ₁ of ring A without the pawl portion 6B ₁ of ring B is the aforementioned fourth
It constitutes the arrangement portion of the illustrated spring member.

As shown in FIGS. 4a and 4b, the spring member 16 has a spring portion 16a exhibiting spring properties in the thrust direction with respect to the optical axis of the lens barrel, and a spring portion 16b exhibiting spring properties in the radial direction.

FIG. 5 is a perspective view of a main part of an assembled drawing in which the tightening rings A, B and the spring member 16 are assembled. When the claws, notches, and protrusions 6A ₃ and 6B ₃ of the tightening rings 6A and 6B are aligned and fixed together, the claw 6A ₁ of the tightening ring A is closer to the claw 6B ₁ of the tightening ring B. By forming it long, the claw part has a single-layer part and a multi-layer part of the tightening ring.
The spring member 16 is placed in the portion _A1 only).

The present invention has fastening rings A and B as shown in FIG.
and the spring member 16 are combined and fixed to the retaining ring 4 as described above in FIG. 1 to constitute a bayonet device.

To attach the lens barrel to the camera using the lens barrel bayonet device configured as described above, as shown in FIG. Tightening of the lens barrel and the camera in the thrust direction is done by rotating the lens barrel and the camera in the thrust direction using the pawls (indicated by two-dot chain lines) on the bayonet parts of the lens barrel and camera and the thrust direction of the spring member 16. The elastic force of the spring portion 16a tightens the lens barrel to the connecting surface on the camera side. The misalignment between the center of the optical axis of the lens barrel and the center of the lens barrel attachment part of the camera is caused by the elastic force of the spring part 16b in the radial direction resisting the weight of the lens barrel and aligning the lens barrel and camera with the center of the optical axis. This can be prevented by acting to

The tightening rings A and B constituting the bayonet member of the bayonet device of the present invention are shown in FIGS.
As shown in Figures a and b, it has a uniform wall thickness and can be made very easily by press working, and has a lens barrel structure in which the mount member 8 shown in Figure 1 is configured to be rotatable around the lens barrel. Tightening ring A,
By making the dimensions A ₄ and B ₄ of the flange portion B different as shown, the mount member can be configured to be prevented from coming off from the lens barrel and to be rotatable.
Forming the claw part of the tightening ring A longer than the claw part of the tightening ring B and providing a place for arranging the spring member 16 is extremely convenient in the manufacturing process compared to forming it as a single part using conventional cutting processing. It can be made easily and at low cost.

Further, in the spring member 16 of the present invention, the thrust direction spring portion 16a and the radial direction spring portion 16b can be formed as a single part by press working or the like, or each of the spring parts 16a and 16b can be made as separate parts. Good too.

The bayonet device of the present invention uses a radial spring to prevent misalignment of the optical axis between the camera and the lens barrel, and allows the lens barrel and the camera signal member to be engaged at the normal engagement position. Correct signals can be exchanged in exposure control operations.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a bayonet device for a lens barrel according to the present invention. FIG. 2a shows a plan view of a tightening ring A forming part of the bayonet member of the bayonet device of the invention. FIG. 2b is a side view of the tightening ring A. Figure 3 a shows the above tightening ring A.
FIG. 2 shows a plan view of a tightening ring B that joins with the bayonet member of the bayonet device. FIG. 3b is a side view of the tightening ring B. FIG. 3c is a bottom view of the tightening ring B. Figure 4a shows the above tightening ring A.
This is a plan view in which a thrust direction spring portion 16a and a radial direction spring portion 16b are integrally formed by a spring member disposed on the inner circumferential surface of the vehicle. FIG. 4b shows a front view of the spring member. FIG. 5 is a perspective view of a main part of a bayonet member in which the above-mentioned tightening rings A and B and the spring member 16 are combined. FIG. 6 is an imaginary diagram showing a state in which a lens barrel using a bayonet device according to the present invention is attached to a camera. 6 (6A, 6B)... Tightening ring, 16... Spring member having spring characteristics in the radial direction and the thrust direction.

Claims (1)

[Scope of Claims] 1. An annular flange fixed to a bayonet mount holding portion of an optical device, and a plurality of rings that are bent in the radial direction integrally with the flange and formed alternately at positions in the circumferential direction. a first bayonet ring comprising a pawl portion and a cutout portion; and a first bayonet ring dimensioned so that at least an inner radial surface of the first bayonet ring joins together;
an annular flange; claws that are bent in the radial direction integrally with the flange and have the same number and phase as the claws and notches of the first bayonet ring; and are formed alternately at circumferential positions; a second bayonet ring having a notch, the length of the claw in the circumferential direction being shorter than the length in the circumferential direction of the claw of the first bayonet ring;
a bayonet ring; the first and second bayonet rings are overlaid and fixed in a multi-layered state to form a bayonet claw at the overlapping portion of the claw portions of both; A spring attached to the inner circumferential surface of the collar of the bayonet ring, extending from the fixed position in the direction of the surface of the claw of the first bayonet ring, and in the normal position, away from the surface of the claw. a first spring part having a spring property in a thrust direction with respect to the optical axis; a second spring part having a spring biasing part that is separate from the inner circumferential surface of the flange part and having spring properties in a radial direction with respect to the optical axis; At least in the vicinity of the single layer portion of the first bayonet claw, which is caused by the difference in length in the circumferential direction of the claws of both the first and second bayonet rings, A bayonet device for an optical device, characterized in that the first spring portion is arranged to match the position of the single layer portion.