Apparatus for supporting and guiding a film strip in a camera

Apparatus for supporting and guiding a film strip, a method for making such an apparatus and a camera incorporating the same. The apparatus includes a pressure plate configured to contact a film strip in a direction which corresponds to an optical axis of the camera, and a plurality of guide rails integrally formed with the pressure plate. The plurality of guide rails are configured to support the film strip during photographic operations and to guide the film strip during film movement operations.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to cameras that utilize film strips and, more 
particularly, to film strip guide systems that are used to position a film 
strip to facilitate photographic operations. 
2. Description of the Related Art 
Film strip guide systems for use in cameras are well known. Such systems 
are used to guide a film strip across an aperture of a camera in order to 
facilitate photographic operations. In addition to guiding a film strip, 
guide systems often are designed to flatten a film strip to ensure 
accurate photographic operations. A typical arrangement of a film strip 
guide system is illustrated in three drawing figures which are attached 
hereto and which have been identified as "FIG. 1,""FIG. 2A," and "FIG. 
2B," respectively. 
In particular, FIG. 1 shows a conventional camera having a camera body 1 
that includes an aperture 1a. Inner rails 1b and outer rails 1c guide a 
film strip across aperture 1a. A separately constructed pressure plate 2 
is used to flatten the film strip to facilitate photographic operations 
within camera 1. In FIG. 1, pressure plate 2 may be fixed to camera body 
1a by screws 3 (FIG. 2A). Accordingly, in camera 1, a film path tunnel or 
channel is formed between pressure plate 2 and camera body 1a through 
which a film strip may be advanced and re-wound. 
FIGS. 2A and 2B, illustrate a film strip 4 within the film path channel 
shown in FIG. 1. The position of film strip 4 in a vertical direction (V) 
within camera 1 is maintained by outer rails 1c. The position of film 
strip 4 in a horizontal direction (H) within camera 1 is maintained by 
inner rails 1b along with pressure plate 2. 
Despite the widespread use of film strip guide systems like or similar to 
those shown in FIGS. 1, 2A, and 2B, such systems are not without their 
problems. For example, such systems are not very effective at ensuring the 
flatness of a film strip to facilitate accurate photographic operations. 
In particular, it is difficult to ensure such flatness between inner rails 
1b and pressure plate 2 as a result of screws 3. Tightening each screw 3 
to ensure that pressure plate 2 is mounted exactly parallel to camera body 
la has been difficult to achieve, especially during automated assembly 
procedures, etc. As a result, a film strip like film strip 4 is able to 
maintain a relatively large crown or bow (as shown in FIG. 2B) which can 
have a negative affect on photographic operations. As such, a particular 
area of a film strip may be maintained in a position that does not adhere 
to a particular focus state within camera 1, thus allowing an otherwise 
focused image to be inaccurately exposed. And, as a result, such 
inaccurate exposures have produced bad and lost photographs. 
Thus, there exists a need to provide a new and improved apparatus for 
supporting and maintaining a film strip in a camera to facilitate 
photographic operations. Such an apparatus must ensure film strip flatness 
without utilizing conventional film path structures such as separately 
mountable pressure plates, etc. To be viable, such an apparatus should 
include both a film guide or rail system and an integrally formed pressure 
plate structure. 
SUMMARY OF THE INVENTION 
The present invention has as its principal object to solve the 
aforementioned problems associated with prior film strip guide systems by 
providing a new and improved film strip guide apparatus that allows 
accurate focal plane positioning through effective film strip arrangement 
and placement. 
It is another object of the present invention to provide an apparatus that 
includes both a film strip pressure plate and an integrally formed film 
strip guide arrangement that enable a film strip to be flattened within an 
exposure area within a camera. 
It is a further object of the present invention to provide an apparatus 
that may be mounted within a camera that enables more accurate and even 
focus states and corresponding photographs to be realized. 
These and other objects of the present invention are achieved by providing 
an apparatus for supporting and guiding a film strip and a camera 
incorporating the same. The apparatus includes a pressure plate configured 
to contact and flatten a film strip in a direction which corresponds to an 
optical axis of the camera, and a plurality of guide rails integrally 
formed with the pressure plate. The plurality of guide rails are 
configured to support the film strip during photographic operations and to 
guide the film strip during film movement operations. 
And, according to another aspect of the present invention, provided is a 
method for making an apparatus for supporting and guiding a film strip in 
a camera. The method includes the steps of forming a pressure plate 
configured to contact a film strip in a direction which corresponds to an 
optical axis of the camera, and integrally forming a guide system with the 
pressure plate. The guide system is configured to support the film strip 
during photographic operations within said camera and to guide said film 
strip during film movement operations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention is now discussed with reference to the drawing 
figures that were briefly described above. A discussion of each preferred 
embodiment of the present invention is followed by a corresponding 
discussion of its operation. Unless otherwise specified, like parts are 
referred to with like reference numerals. 
Referring now to FIGS. 3A, 3B, 3C, and 3D, depicted therein are diagrams of 
a film strip guide apparatus according to a preferred embodiment of the 
present invention. In particular, a back member of film strip guide 
apparatus 10 includes openings 10b and 10c which are disposed and formed 
therein (e.g., molded, machined, etc.). Formed on an interior surface of 
the back member of apparatus 10 is a pressure plate 10h. Visible within 
openings 10b and 10c are parts of a front member of apparatus 10. Formed 
on an interior surface of the front member of apparatus 10 are outer film 
guide rails 10f (FIG. 3C) and inner film guide rails (10g). As shown in 
FIGS. 3B and 3D, a film path is accessible from integrally formed openings 
10d and 10e which are formed at respective sides of apparatus 10. 
It is important to note that the aforementioned structures of apparatus 10 
have been integrally formed through use of molding techniques (e.g., 
plastic molding techniques, metal molding techniques, etc.). Other 
techniques may be employed including, but not limited to, machining 
techniques, etc. 
Referring now to FIG. 4, depicted therein is a cross section diagram of 
apparatus 10 in an operational state. A film strip 4 is positioned and 
maintained within apparatus 10 relative to an optical axis (OA) of a 
camera (not shown). As shown, a back surface side of film strip 4 is in 
contact with (e.g., pushed by) pressure plate 10h. Film strip 4 is held in 
place and prevented from moving vertically within apparatus 10 by outer 
rails 10f which form a channel in which film strip 4 may move. Inner rails 
log contact and push against edges of film strip 4 to keep it in a 
relatively flattened state against pressure plate 10h within apparatus 10. 
Referring now to FIG. 5, depicted therein is an oblique diagram of film 
strip guide apparatus 10. As show, an opening like opening 10e, allows a 
film strip like or similar to film strip 4 (FIG. 4) to pass through 
apparatus 10. 
Referring now to FIG. 6, depicted therein is an oblique diagram of 
apparatus 10 when placed into a camera body. A front body member 11 
includes a lens mounting plate 11a. The camera also includes a rear body 
member 12. Within the camera is a focal plane shutter device 13. Front 
body member 11 is fixed to rear body member 12 by a fastening arrangement 
such as by screws 14 and 15, etc. 
Apparatus 10 is fixed to front body member 11 by screws 16 which pass 
through fastener holes 10i and which come into operative engagement with 
mounting sockets 11b (e.g., threaded holes configured to receive screws, 
etc.). The distance from lens mounting plate 11a to the film path provided 
within apparatus 10 and a film strip that may be maintained therein may be 
accurately and uniformly maintained by controlling the mounting position 
of apparatus 10. 
Accordingly, referring now to FIG. 7, depicted therein is a cross section 
diagram of the camera shown in FIG. 6. A mount 17 is disposed to receive a 
lens (not shown). A film cartridge 18 such as an advanced photographic 
system (APS) film cartridge, a 35 mm film cartridge, etc. is housed in a 
cartridge compartment 12a disposed in rear body member 12. Also disposed 
within rear body member 12 is a spool 20 for use in film windup which is 
housed in a spool compartment 12b. A film roller assembly 21 makes film 
winding possible. A spool compartment 22 cover covers spool compartment 
12b and, also supports film roller assembly 21 in a rotating fashion. An 
additional film roller assembly 23 makes film winding possible. A film 
guide member within spool compartment 12b supports film roller assembly 23 
and also includes a film guide unit 24a which is disposed near film path 
guides 12d and 22a. 
In the present preferred embodiment, apparatus 10 has been mounted to a 
front body member of a camera. The present invention, however, is not so 
limited. To the contrary, apparatus 10 may be mounted to the back body 
member of a camera. 
In operation, by rotating film windup shaft 18a in a film start direction, 
a film strip is expelled (moved) from within cartridge 18 and from a 
cartridge compartment outlet formed between film path members 12c and 19a. 
Thereafter, the film strip passes through the film path formed in 
apparatus 10 to advance into spool compartment 12b and to be wound onto 
spool 20. The film strip will be pressed by and against pressure plate 10h 
(e.g., as shown in FIG. 4) to achieve a relatively flat imaging surface 
(focal plane) in accordance with the present invention. 
Many modifications may be made to apparatus 10 in accordance with the 
present invention. For example, openings 10b and 10c of apparatus 10 may 
be formed in a vertical direction. Additionally, the comer or peripheral 
edges of pressure plate 10h need not necessarily have a right-angle 
cross-section, and may be formed with other shapes (e.g., rounded, 
beveled, slanted, etc.) like or similar to rounded edge RE (FIG. 8D) to 
suit particular design requirements such as to protect a film strip 
surface from scratches and abrasions, etc. 
In any case, an apparatus and a camera including the same according to the 
present invention, can realize accurate film positioning and flattening 
characteristics. Such accuracy will result in fewer lost photographs due 
to focus problems and the like which often result from negatives that are 
not properly exposed. 
Thus, having fully described the present invention by way of example with 
reference to the attached drawing figures, it will be readily appreciated 
that many changes and modifications may be made to the invention and to 
the embodiments shown and/or described herein without departing from the 
spirit or scope of the present invention which is defined in and covered 
by the appended claims.