Photography – With film drive – Mechanical detail
Reexamination Certificate
1995-06-07
2001-08-07
Gray, David M. (Department: 2851)
Photography
With film drive
Mechanical detail
C396S538000
Reexamination Certificate
active
06270264
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a camera and, more particularly, to an improvement in a film transport device for maintaining the alignment of a film cartridge.
2. Description of the Prior Art
Recently, a type of camera has been proposed in U.S. Pat. No. 4,864,332 in which a film having a magnetic memory portion is used and information such as, a shutter speed, an aperture value, and a title are written on or read from this magnetic memory portion by a magnetic head.
Also, a pre-wind type of camera has been proposed and manufactured as an article of commerce in which the film is first wound around a spool and is then rewound into the film cartridge each time a frame is exposed. If the pre-wind type of camera is provided with a magnetic head and the film having a magnetic memory portion mentioned above, the following problem arises.
In order to write information on the magnetic memory portion of the film or reading out information therefrom, it is necessary to feed the film at a constant and a high speed.
The reason why feeding the film at a constant speed is necessary is because in a case where signals are read by the magnetic head as changes in the magnetism of the magnetic memory portion occur, the intervals of the signals are recognized as the content of information stored on the magnetic memory portion. Thus, a change in the film feed speed causes a change in the intervals of the signals, resulting in a detection failure.
The reason why feeding the film at a high speed is necessary is that unless the film is fed at a high speed, the magnetic flux will change so little so that the desired accuracy of the signals cannot be obtained.
Information may be written on or read from the magnetic memory portion of the film while the film is being rewound in the film cartridge. During this operation, if the film cartridge is inclined relative to the axis of a film rewinding fork, a shaft of the film cartridge and the film rewinding fork cannot be smoothly engaged and the load imposed on the film rewinding fork fluctuates. The film rewinding speed is thereby changed, resulting in an error in writing or reading information with the magnetic head.
This problem will be explained below with reference to
FIGS. 7
,
8
and
9
.
FIG. 7
is a longitudinal sectional view of a film cartridge chamber
111
a
in which a film cartridge
112
is accommodated in a camera body
111
. Film cartridge
112
has a portion
112
a
for engagement with a fork portion
113
a
of a film rewinding fork
113
to which a fork drive gear
113
b
is connected.
Generally, the film cartridge size varies within the tolerance limit, and film cartridge chamber
111
a
has a size slightly larger than the film cartridge size so as to receive a film cartridge
112
in any shape. Ordinarily, for this reason, film cartridge
112
is set in film cartridge chamber
111
a
comparatively loosely so as to be off-centered relative to film cartridge chamber
111
a
at its one end while being engaged at the other end with the film rewinding fork portion
113
a.
A spring member (not shown) or the like may therefore be used to press film cartridge
112
on the surfaces of portions
111
b
and
111
c
of the film cartridge
112
, to prevent play between the film cartridge
112
and the camera body surfaces
111
b
and
111
c
, as shown in FIG.
8
. However, as shown in
FIG. 9
, in the case of the ordinary film cartridge, the center defined by center lines
113
C
1
and
113
C
2
of the film rewinding fork, i.e., the axis of the film rewinding fork and the center defined by center lines
112
C
1
and
112
C
2
of the film cartridge, i.e., the axis of the film cartridge deviate from each other, since the axial center position of the film rewinding fork in the film cartridge chamber is determined so that a film cartridge having a maximum size can be suitably received as mentioned above. Therefore, the film rewinding fork cannot be driven smoothly and the film rewinding speed is changed.
SUMMARY OF THE INVENTION
In view of these circumstances, an object of the present invention is to provide a camera comprising a cartridge setting chamber in which a film cartridge is set, a fork rotatably disposed in the cartridge setting chamber and engagable with a rotary shaft of the film cartridge to feed a film in the film cartridge, and a cartridge support member provided in the cartridge setting chamber in a position opposite to that of the fork and engagable with the rotary shaft of the film cartridge, the rotary shaft of the film cartridge being pinched between the cartridge support member and the fork, wherein the film cartridge can be prevented from being inclined during film feeding, so that a constant film feeding speed can be maintained.
The invention in another aspect pertains to a camera comprising a cartridge setting area in which a film cartridge is set, film feed means for feeding a film in the film cartridge set in the cartridge setting area, and cartridge pinching area means for pinching, with the film feed means, a rotary shaft of the film cartridge set in the cartridge setting area.
The invention in a further aspect pertains to a film cartridge loader for use in a camera comprising a cartridge setting chamber in which a film cartridge is set, a fork rotatably disposed in the cartridge setting chamber, the fork engaging with a rotary shaft of the film cartridge to feed a film in the film cartridge, and a cartridge support member provided in said cartridge setting chamber in a position opposite to that of the fork, the cartridge support member engaging with the rotary shaft of the film cartridge, the rotary shaft of the film cartridge being pinched between said cartridge support member and the fork.
The invention in yet another aspect pertains to a film cartridge loader for use in a camera comprising a cartridge setting area in which a film cartridge is set, film feed means for feeding a film in the film cartridge set in the cartridge setting area, and cartridge pinching means for pinching, with the film feed means, a rotary shaft of the film cartridge set in the cartridge setting area.
Other objects of the present invention will become apparent from the following description of preferred embodiments of the present invention.
REFERENCES:
patent: 4647170 (1987-03-01), Stoneham
patent: 4864332 (1989-09-01), Harvey
patent: 4870437 (1989-09-01), Omaki et al.
patent: 5005031 (1991-04-01), Kelbe
patent: 5016030 (1991-05-01), Dwyer et al.
patent: 2-067538 (1990-03-01), None
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Gray David M.
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