JPS6124976Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a focus adjustment mechanism for a focus plate mounting device in a single-lens reflex camera in which the focus plate can be replaced from the lens attachment/detachment mount side.

In conventional single-lens reflex cameras, where the focusing plate can be replaced from the lens attachment/detachment mount side, a focusing plate replacement mechanism that follows the focusing mechanism is required to adjust the focus, resulting in an increase in the number of parts or adjustment work. This was causing complications.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to easily perform focus adjustment work in a reticle mounting device using a simple adjustment mechanism.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a cross-sectional side view of an embodiment of the present invention, and FIG. 2 shows a perspective view of the same embodiment when the focusing plate is replaced.

The focus plate 1 is held by a receiving surface 2a of a focus plate support frame 2, and rotation shafts 3 are implanted on both rear side surfaces of the focus plate support frame 2.

The focus adjustment leaf spring 4 is attached to the camera body (not shown) at its center, and its bent portion 4
a engages with the rotating shaft 3 of the focus plate support frame 2 to rotatably support the focus plate support frame 2 relative to the camera body, and the focus adjustment frame 5 comes into contact with the focus plate support frame 5 near and above the pivot support. The focus adjustment frame 5 is urged upward of the camera body by contacting the portion 5a.

Therefore, the focus adjustment frame 5 and the focus plate holder frame 2 are held integrally at the rear.

On the other hand, a locking tongue piece 2b is provided in front of the focus plate receiving frame 2, and a locking tongue piece 2b is provided in front of the focus adjustment frame 5.
A locking portion 8 is provided to engage with the locking tongue 2, and by abutting and engaging the locking tongue piece 2 with the locking portion 8, the focus plate holder frame 2 and focus adjustment frame 5 are integrated even when viewed from the front. will be retained.

Focus plate holding springs 7 are attached to both inner sides of the focus adjustment frame 5, and these springs 7 urge the focus plate 1 downward to the camera body and press it against the receiving surface 2a of the focus plate holder frame 2. I'm letting you do it.

The front leaf spring part 4b of the focus adjustment leaf spring 4 also comes into contact with the front abutment part 5b of the focus adjustment frame 5, and urges the focus adjustment frame 5 upwards on the camera body. When the piece 2b is engaged with the locking portion 8, the focus adjustment frame 5 is always urged upwardly by the adjustment plate spring 4 both at the front and the rear.

The flanged screw 6, which is a positioning member, has a flanged portion that abuts each of the three bent portions 5c provided on the focus adjustment frame 5, and each of the flanged screws 6, which is a positioning member, abuts each of the three bent portions 5c provided in the focus adjustment frame 5 through a hole drilled in each of the bent portions 5c. The focus adjustment frame 5 is screwed to the camera body by screwing the bent portion 5c, and is urged upward by the focus adjustment leaf spring 4 by adjusting the rotation of each flanged screw 6. The vertical position of the focus adjustment frame 5 with respect to the camera body is adjusted by moving the focus adjustment frame 5 in the vertical direction of the camera body.

In the above configuration, the locking tongue piece 2b and the locking portion 8
When they are engaged (the state shown in FIG. 1), the focus plate 1 is held by pressure on the receiving surface 2a of the focus plate support frame 2, and the focus plate support frame 2 is held integrally with the focus adjustment frame 5. Since the position, especially the position of the lower surface of the focusing plate 1, is determined by the rotation of the focusing plate 1, the lower surface of the focusing plate 1 can be aligned with the focal position of the camera by simply adjusting the rotation of each flanged screw 6.

When replacing the focus plate 1, pull the locking portion 8 of the focus adjustment frame 5 forward to release the engagement with the lock tongue piece 2b, and the spring force of the focus plate presser spring 7 and the focus plate 1 Since the focus plate support frame 2 rotates downward about the rotation shaft 3 due to the weight of the focus plate support frame 2, the focus plate 1 can be replaced from the lens attachment/detachment mount side.

According to the above configuration, each flanged screw 6
By positioning the focus adjustment frame 5 and the focus plate holder frame 2 according to Regardless of its thickness, the lower surface of the focusing plate 1 can be positioned at the focal point of the camera simply by engaging the locking tongue piece 2b with the locking portion 8, regardless of its thickness. No adjustment is required.

As described above, in the focus adjustment mechanism according to the present invention, the positioning member for focus adjustment can be adjusted without separately installing an adjustment member on the locking part of the focus plate holder frame or the rotation axis for focus adjustment. Focus adjustment can be completed by simply operating it, which not only reduces the number of parts and simplifies adjustment work, but also allows focus adjustment to be done once, even if a focus plate of different thickness is used. There is no need to do this.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing one embodiment of the present invention. FIG. 2 is a perspective view of the same embodiment when the focusing plate is replaced. 1: Focus plate, 2: Focus plate receiving frame, 2a: receiving surface, 2
b: Locking tongue piece, 3: Rotation shaft, 4: Focus adjustment leaf spring, 4a: Folding bending shaft support, 4b: Front leaf spring part, 5: Focus adjustment frame, 5a: Rear abutting part, 5b:
Front abutting part, 5c: bending abutting part, 6: flanged screw (positioning member), 7: focusing plate holding spring, 8: locking part.

Claims (1)

[Scope of utility model registration request] In a focus adjustment mechanism of a focus plate mounting device in a single-lens reflex camera in which the focus plate can be replaced from the lens attachment/detachment mount side, the focus plate holder frame holds the focus plate and has a locking tongue piece at the front; a focus adjustment frame having a locking portion positioned above the focus plate support frame and locking the locking tongue; and a focus plate attached to the focus adjustment frame to press the focus plate onto the receiving surface of the focus plate support frame. a presser spring; a focus adjustment plate spring attached to the camera body so as to rotatably support the focus plate support frame relative to the camera body and urge the focus adjustment frame upwardly on the camera body; The vertical position of the focus adjustment frame with respect to the camera body can be adjusted by moving the focus adjustment frame in the vertical direction of the camera body with the focus adjustment frame being biased upwardly by the adjustment plate spring. 1. A focus adjustment mechanism for a focus plate replaceable viewfinder, comprising a positioning member and capable of performing focus adjustment by adjusting only the positioning member.