Photography – Camera detail – Film restraining means or pressure plate
Reexamination Certificate
1999-06-07
2001-04-17
Gray, David M. (Department: 2851)
Photography
Camera detail
Film restraining means or pressure plate
C396S538000, C396S541000
Reexamination Certificate
active
06217237
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a spool case unit which is provided for a camera using a long and narrow film, the spool case having a spool shaft housed therein for winding the film loaded from outside into the camera, and a camera having such a spool case unit.
In connection with the conventional spool case unit, the main structural elements are formed of a metal or synthetic resin material, as an integral unit, together with the frame of the camera which uses the spool case unit, by injection molding.
Recently, there is a great demand for the reduction of the size of the external dimension of the camera and its weight. However, with the conventional spool case unit which includes the main structural elements formed integrally with the frame of the camera as described above, it is very difficult to satisfy the above described demand. More specifically, there is a limitation in reducing the thickness of the main structural elements, under consideration of the flow of the molten metal or synthetic resin during the injection molding process. In order to reduce the external dimension of the camera and its weight further than the present level, the conventional method of manufacturing a spool case unit, must be changed.
Jpn. Pat. Appln. KOKAI Publication No. 7-20565 discloses a technique in which a part of the side wall of the outer shell, the shell being a main structural element of the spool case unit, is made of an elastic thin plate. The part of the side wall is located adjacent to the lens barrel of the camera. This structure makes it possible to place the spool case unit slightly closer to the lens barrel than in the conventional camera, and contributes to the slight reduction of the weight of the spool case unit.
Jpn. Pat. Appln. KOKAI Publication No. 4-340529 discloses a structure in which a motor is placed within the spool shaft of the spool case unit in order to reduce the size of the camera. According to the structure disclosed in this publication, the outer shell of the spool case unit is composed of two-divided upper and lower halves. In order to assemble the spool case unit, the motor is fixed with screws at a predetermined position in the upper half of the outer shell of the spool case unit, and then the lower half of the outer shell is fixed to the upper half while the center hole of the spool is rotatably fitted on the circumference of the motor. Thus, the structure of the spool case unit disclosed in Jpn. Pat. Appln. KOKAI Publication No. 4-340529 makes an assembly of the camera complicate. Further, this structure does not exhibit any weight reducing technique.
This invention is derived from the above described circumstances, and an object of the present invention is to provide a spool case unit for a camera, which has a simple structure, can be easily assembled, and enables a reduction of the external dimension of the camera and its weight, as well as a camera which includes the above described spool case unit.
BRIEF SUMMARY OF THE INVENTION
In order to achieve the above-described object, a spool case unit for a camera using a long and narrow film, which is according to the present invention, and which is located adjacent to a lens barrel of the camera, and houses a spool shaft for winding up the film loaded into the camera from outside, the spool case unit comprising:
a pair of end walls which are arranged in both end sides of the film to be wound up onto the spool shaft in a width direction of the film;
a connecting member which is provided between the pair of end walls, connects the pair of end walls to each other, and faces a portion of an outer circumferential surface of the film wound up onto the spool shaft; and
an elastic thin plate which is composed of a thin plate having elasticity, and cooperates with the connecting member so that a side wall for the spool case unit is formed between the pair of end walls, the side wall surrounding the outer circumferential surface of the film wound onto the spool shaft, and an area of the thin plate being larger than that of the connecting member in the side wall.
In the spool case unit for a camera, according to the present invention and structured as described above, the connecting member and the elastic thin film cooperate to surround the outer circumferential surface of the film wound onto the spool shaft between the pair of end walls, and form a side wall for a spool case unit between the pair of the end walls. The elastic thin plate has an area larger than that of the connecting member in the side wall.
The elastic thin plate having a film surrounding area larger than that of the connecting member, promotes the lightening of the weight of the spool case unit and further that of the camera which uses the spool case unit.
The elastic thin plate reduces the external dimension of the portion of the side wall, the portion being constituted by the elastic thin plate in the spool case unit. Therefore, the elastic thin plate having a film surrounding area larger than that of the connecting member significantly reduces the external dimension of the outer circumferential surface of the side wall in the spool case unit. Further, the external dimension of the camera which uses the spool case unit can be significantly reduced.
In the spool case unit for a camera, according to the present invention, it is preferable that the elastic thin film is made of a metal or a synthetic resin having a light shielding property.
The elastic thin film preferably has an electric conductivity, and is grounded when the spool case unit for a camera, according to the present invention, is set onto the camera.
With this structure, even if the film wound onto the spool shaft of the spool case unit generates static electricity due to friction, the static electricity can be discharged via the elastic thin plate. Therefore, attachment of dusts onto the film or various members in the spool case unit, caused by the static electricity, can be prevented, and further possible damages caused to the film as it moves and rubs against the dusts in the spool case unit can be prevented.
The elastic thin film is preferably composed of a single material, and is fixed to the connecting member. This structure makes the structure of the spool case unit being simple, and accordingly, the assembly work for the spool case unit can be facilitated.
The elastic thin plate is so preferably structured that it generates an urging force directing inwards in the radial direction of the spool shaft between the pair of the end walls, and makes the urging force act onto the pair of the end walls so that the positioning of the thin plate around the outer circumferential surface of the film on the spool shaft between the pair of the end walls is carried out. This structure also makes the structure of the spool case unit being simple, and the assembly work for the spool case unit also can be facilitated.
In order to achieve the above-described object of the present invention, another spool case unit for a camera, according to the present invention, is located adjacent to a lens barrel of the camera, the camera using a long and narrow, and houses a spool shaft for winding up a film loaded into the camera from outside, the spool case unit comprising:
a pair of end walls which are arranged in both end sides of the film to be wound up onto the spool shaft in a width direction of the film;
a connecting member which is provided adjacent to the lens barrel, connects the pair of end walls to each other, and faces a portion of an outer circumferential surface of the film wound up onto the spool shaft; and
an elastic thin plate which is composed of a thin plate having elasticity, and cooperates with the connecting member so that a side wall for the spool case unit is formed between the pair of end walls, the side wall surrounding the outer circumferential surface of the film wound onto the spool shaft, and an area of the thin plate being larger than that of the connecting member in the side wall.
With such another spool case unit for a camera, according to the
Shimizu Tokuo
Takagi Tetsuya
Terada Hiroshi
Ue Takaaki
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Gray David M.
Olympus Optical Co,. Ltd.
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