JPH0241615Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a guide tube for supporting a photographic lens of a camera so that it can move forward and backward in the direction of its optical axis. This invention relates to a guide tube extension device that can be extended as appropriate.

[Conventional technology]

Large-format cameras that use 120-size film and view cameras for photo shoots use larger and heavier lenses. For cameras that use such large lenses, simply connecting the camera and lens with a bayonet mount, which is often used with 35mm cameras, is not strong enough. For this reason, a guide tube protruding in the optical axis direction of the lens is fixed to the camera body side, and the lens holding unit holding the lens is supported by the guide tube, and when adjusting the focus, the lens holding unit is fixed to the guide tube. It is made to move forward and backward along the tube.

By the way, in such cameras, the amount that the lens extends is limited by the length of the guide tube, so it is useful for telephoto shooting that uses a long focal length lens, close-up shooting that requires a large amount of lens extension, etc. In order to enable special shooting of
It is necessary to keep the guide tube long. Under these circumstances, in conventional cameras in which the lens is supported by a guide tube, a rather long guide tube is provided protruding from the camera body in order to satisfy the versatility of photographing.

[Problem that the invention attempts to solve]

However, when considering the general mode of photography targeted at many users, opportunities for telephoto photography or close-up photography as described above are extremely rare. Therefore, integrating a long guide tube into the camera is often not only a waste of time, but also a hindrance to handling.

The present invention was developed in view of the above conventional technology, and the length of the guide tube fixed to the camera body is kept to a length that can be used for general photography, and when necessary, it can be used. To provide a camera guide tube extension device which can be easily extended.

[Means for solving problems]

In order to achieve the above object, the present invention is such that an extension rod can be detachably attached to the tip of a guide tube fixed to a camera body. This extension rod consists of a hollow outer cylinder and a connecting member fitted into the outer cylinder so as to be rotatable and prevented from moving in the axial direction. One end of the connection member is formed with a thread that is threaded into a threaded hole at the tip of a guide tube protruding from the camera body, and the other end is formed with a threaded hole that is the same as the threaded hole of the guide tube. . After the tightening bolt is screwed into the screw hole of the connecting member, by further rotating the tightening bolt, the thread of the connecting member is screwed into the screw hole of the guide tube. This allows the extension rod to be connected to the guide tube.

In a preferred embodiment of the invention, in order to stabilize the movement of the lens board, a pair of guide tubes are provided, each of which is connected to an extension rod. In order to connect the respective tips of the extension rods and maintain parallelism between the two, a front plate is also attached by threading the bolts.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 4 showing the appearance of a camera using the present invention, for example, 120 mm is provided on the back side of the camera body 1.
A film magazine 2 loaded with a roll film of the same size is attached, and upon receiving an electric signal from the camera body 1, the film is automatically wound up. Furthermore, a viewfinder hood 3 that can be opened and closed is provided on the top surface of the camera body 1, and by opening it, a focus plate is exposed, which allows focus adjustment and framing to be performed. A pair of guide tubes 6, 6 that protrude forward are fixed to the lower part of the camera body 1. As shown in FIG. 1, a groove 6a extending in the longitudinal direction is formed in the upper surface of the guide tubes 6, 6, and a rack 7 is fixed in this groove 6a.

A feeding base 8 is supported by the pair of guide tubes 6, 6. The feeding base 8 is provided with a feeding knob 9 which can be rotated freely. When the feeding knob 9 is rotated, the pinion 10
The shaft 11 to which is fixed rotates. Since the pinion 10 is engaged with the rack 7, by rotating the feeding knob 9, the feeding base 8 can be moved forward and backward along the guide tubes 6, 6. In addition, rack 7 and pinion 1
In order to precisely guide the feeding base 8, the teeth are engaged with each other through diagonally arranged tooth rows.

The feeding base 8 is provided with a standard 12 which is slidable in the left and right directions and is rotatable around a vertical axis. and,
A lens board 14 is attached to the standard 12 so as to be slidable vertically and rotatable around a horizontal axis. This allows the lens board 14 to be tilted in four directions. A lens unit 17 in which a photographic lens 16 is incorporated is fixed to the lens board 14 by a lock lever 15. The back surface of the lens board 14 and the front surface of the camera body 1 are optically connected by a bellows 18.

When performing focus adjustment, by rotating the feeding knob 9, the feeding base 8 is moved forward and backward in the optical axis direction of the photographic lens 16 via the pinion 10 and the rack 7. This is a standard lens, and when normal photography is performed using this lens, the extending base 8 is advanced most forward when photographing is performed at the close photographing distance of the photographing lens 16.
A guide tube 6 protruding from the camera body 1,
The length of No. 6 is set in consideration of the maximum amount of feedout at this time.

When attaching the attachment lens 20 to the photographic lens 16 and attempting to perform close-up photography, it is necessary to extend the extension base 8 further forward. In this case, since the length of the guide tubes 6,6 is insufficient, extension rods 22,22 are attached to the tips of the guide tubes 6,6 as shown.

As shown in FIG. 2, the extension rod 22 is
Hollow pipe 3 with the same outer diameter as the guide tube 6
0, and a connecting bolt 32 rotatably inserted into the hollow part of this pipe 30. Similar to the guide tube 6, the pipe 30 has a rack 23 embedded in its outline, and one end 23a.
protrudes from the end of the pipe 30. A thread 34 is formed at one end of the connection bolt 32 to be screwed into a threaded hole 33 formed at the tip of the guide tube 6, and a threaded thread 34 is formed at the other end to fit into the threaded hole 33 formed at the tip of the guide tube 6.
A screw hole 35 equal to 3 is formed. The connecting bolt 32 is inserted into the pipe 30 from the left side in FIG.
A locking nut 36 is then screwed onto the thread 34 of the holder. After the nut 36 has passed through the thread 34, the thread formed on the outer periphery of the nut 36 is screwed into the thread formed on the inner periphery of the pipe 30, and the nut 36 is integrated with the pipe 30. be done. As a result, the connecting bolt 32 is rotatable within the pipe 30 and is not easily removed in the axial direction.

When connecting the extension rods 22, 22 to each of the pair of guide tubes 6, 6, align the thread 34 of the connection bolt 32 with the screw hole 33 formed at the tip of the guide tube 6, and then tighten the connection bolt 32. Turn and screw these two together. For this reason, an engagement groove 37 is formed at the other end of the connection bolt 32, and the connection bolt 32 can be easily rotated by engaging a coin or the like with this engagement groove 37. Further, by fitting the end portion 23a of the rack 23 into the groove 6a formed by partially cutting out the rack 7 of the guide tube 6, the guide tubes 6, 6 and the extension rod 22, The connection position with 22 can be easily known. And with this, easy 7,
7 and the racks 23, 23 are less likely to form a step or shift, which is also effective in smoothing the movement of the feeding base 8.

After attaching the extension rod 22 to the tip of the guide tube 6, pass the front plate 25 over the front ends of the extension rods 22, 22, and then tighten the tightening bolts 24.
is screwed into the threaded hole 35 of the connecting bolt 32. When the bolts 24 are tightened, the guide tubes 6, 6, the extension rods 22, 22, and the front plate 25 are firmly integrated with each other. Note that after the connecting bolt 32 has been screwed to some extent into the threaded hole 33 at the tip of the guide tube 6, the screwing of the guide tube 6 and the connecting bolt 32 can be completed simply by screwing the tightening bolt 24. The connection bolt 32 and the tightening bolt 24 can also be threaded together in parallel.

By connecting the extension rods 22, 22 to the tips of the guide tubes 6, 6 in this way,
By operating the feeding knob 9, the feeding base 8 can be fed further forward. Also,
Since the ends of the extension rods 22, 22 are connected by the front plate 25, the parallelism of the pair of guide tubes 6, 6 and the extension rods 22, 22 is reliably maintained, and within the movement range of the feeding base 8. Therefore, the optical axis of the photographing lens 16 will not be eccentric.

When removing the extension rod 22, use a coin or the like to remove the connecting bolt 24, remove the front plate 25, and then rotate the connecting bolt 32 to guide it. It can be removed from the tube 6. When performing normal photography without using the extension rod 22, a front plate 25 can be attached to the tip of the guide tube 6 using the bolts 24, as shown in FIG. In this case, since the pipe 30 and the connecting bolt 32 are not separated from the unused extension rod 22, there is an advantage that it can be easily stored. Incidentally, if a Teflon ring or the like is inserted into the sliding contact portion between the pipe 30 and the connecting bolt 32, the rotating operation of the connecting bolt 32 can be facilitated. and,
Since the screw hole 35 is exposed at the tip of the connecting bolt 32, if the connection with the rack 23 is taken into account, the extension rod 22 with a similar structure can be used.
It is also possible to connect further.

[Effect of idea]

According to the present invention configured as described above, the length of the guide tube fixed to the camera body can be set to a length that can accommodate frequent shooting, so that it can be easily used during use and storage. This makes it easier to handle the camera, and when necessary, the length can be extended as needed by connecting an extension rod. Furthermore, the extension rod of the present invention has the advantage that it can be handled as a single component, making it easy to store when not in use.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts showing an embodiment of the present invention. FIG. 2 is a sectional view of a main part showing an embodiment of the present invention. FIG. 3 is a sectional view of the main part showing the state when no extension tube is used. FIG. 4 is an external perspective view of a camera using the present invention. 1...Camera body, 6...Guide tube,
7... Easy, 8... Payout base, 20...
Attachment lens, 22...Extension rod, 2
3...Rack, 24...Bolt, 25...Front plate,
30...pipe, 32...connection bolt.

Claims (1)

[Scope of claims for utility model registration] (1) In order to move the photographic lens forward and backward in the optical axis direction,
A camera in which a lens board holding a photographic lens is guided by a guide tube protruding from the camera body includes a hollow outer tube having an outer diameter equal to that of the guide tube, and a rotary tube inside the outer tube. It is fitted in such a way that it can move freely but not in the axial direction, and has a thread formed at one end to be screwed into the threaded hole formed at the tip of the guide tube, and a screw thread formed at the tip of the guide tube at the other end. A camera guide comprising: an extension rod comprising a connecting member having a threaded hole equal to the hole; and a tightening bolt screwed into the threaded hole formed at the other end of the connecting member. Tube extension device. (2) Each of the guide tube and the outer cylinder is fitted with a pipe having a circular cross section, embedded in the contour of the pipe along the length of the pipe, and meshed with a pinion rotatably provided on the lens board. A guide tube extension device for a camera according to claim 1, characterized in that the camera guide tube extension device is comprised of a rack. (3) An end portion of the rack partially protruding from one end of the outer cylinder is fitted into a recess formed by partially cutting out the rack on the distal end side of the guide tube. A guide tube extension device for a camera according to claim 2 of the patented utility model.