Collapsible roll film camera

Abstract: The invention relates to a photographic camera having a device for winding a film strip (21) to form a cylindrical film roll, wherein a film take-up chamber (20) has a flexible arcuate film guide which allows the outside diameter of the film roll to increase. The camera is provided with a housing (11) to which a front plate (12) is hinged, and in which a lens plate (14) including a taking lens (15) is slidably guided in the direction of an optical axis. A one-piece flexible web (18) which forms a loop-shaped film feed chamber (19) and a loop-shaped film take-up chamber (20) is located inside said housing (11). The thickness of said housing (11) is smaller than the diameter of said loop-shaped chambers (19, 20) measured in the direction of said optical axis so that said flexible loop-shaped chambers (19, 20) and the film strip (21) are formed into an oval shape when said front plate (12) is in its closed position.

Description: Field of the Invention The present invention relates to a photographic camera having a device for winding a film strip to form a cylindrical film roll, wherein a film take-up chamber has a flexible arcuate film guide which allows the outside diameter of the film roll to increase. In the prior art document US-A-5,544,833 a film roll accumulating device is disclosed for forming a film strip into a film roll used in the take-up chamber of a camera. This device comprises an arcuate film guide which, when additional film is fed in, increases its outer diameter. This is founded on the fact that the inside diameter of a cylindrical film roll does not change as additional film is fed into the take-up chamber. In such a case, only the outer diameter of a film roll is caused to increase. Examples of conventional photographic cameras are disclosed in US-A-5 241 338, US-A-3 750 549, US-A-4 336 986. Problem to be Solved by the Invention It is an object of the invention to provide a photographic camera having a very flat housing measured in the direction of the optical axis. Another object is to provide for such a camera a device for moving a film strip from a film feed chamber into a film take-up chamber where the film strip is received. Summary of the Invention According to the invention this object is attained by means of a photographic camera as defined in claim 1. The camera is provided with a tension spring which, with its one end, is connected to at least one of the opposite ends of a web and, with its other end, is fixed to said housing, whereby the diameter of the film take-up chamber increases by stretching said tension spring when said film strip is fed into said take-up chamber. When the photographic camera is brought into its ready position in which it is ready for taking pictures, i.e. when the front plate is in its opened position and the lens plate is positioned in its taking position in which the bellows is unfolded , the loop-shaped chambers together with the included film strip return from an oval shape into the cylindrical shape because of their flexibility. In detail, the web can be formed such that within an area of said film take-up chamber and/or said film feed chamber said web has a width which is greater than the width of the remaining part of said web, and wherein in said area a cut-out section is provided having a width greater than the width of said remaining part of said web forming two arms on each side of said cut-out section to which one of said tension springs is connected each, and wherein said remaining part of said web is guided such that said loop-shaped chambers are formed. Further features and advantages of the invention can be inferred from the sub-claims and are described with reference to an embodiment shown in the drawing. Brief Description of the Drawings The drawing shows in Fig. 1 a photographic camera according to the invention in its ready position in a top view, Fig. 2 the camera according to Fig. 1 in its closed rest position in a top view, Fig. 3 a detail of a film take-up chamber of the camera according to Fig. 1 in a three-dimensional view, Fig. 4 the detail of the film take-up chamber according to Fig. 3 in a side-view, and Fig. 5 a web for forming the film take-up chamber according to Fig. 3 in a plan view. Detailed Description of the Invention Referring to the drawings, Fig. 1 shows a photographic camera 10 comprising a very flat housing 11. A front plate 12 consists of two halves 12a and 12b which are hingedly mounted on opposite sides of the housing by joints 13a and 13b. The halves 12a and 12b are in their opened positions and a lens plate 14 including a taking lens 15 is positioned in its picture-taking position. The lens plate 14 is connected to the housing 11 by a bellows 16 in a light-tight manner. Each of the halves 12a and 12b is provided with a guide rail 17 for slidably guiding the lens plate 14 from its rest position to its ready position where it is fixed and back to its rest position in which the camera is in its non-use position, as shown in Fig. 2. Inside the housing 11, a one-piece web 18 of flexible material is placed which forms at opposite ends of the housing a loop-shaped film feed chamber 19 and a loop-shaped film take-up chamber 20, the diameters of said chambers being greater than the 20, whereby the film strip is moved across a film gate 22 by a film advance member 28 having an outside grip 29. The transportation of the film strip from one image frame to the next is accomplished when the camera is in its ready position, i.e. the halves 12a and 12b are opened and the lens plate 14 has moved into the picture-taking position. In this position, the loop-shaped chambers 19 and 20 and the scrolled film rolls located in the chambers have a cylindrical shape, which makes the transportation of the film possible. In the collapsed condition of the camera, when the halves 12a and 12b of the front plate 12 are closed, the cylindrically shaped chambers 19 and 20 are pressed together into an oval shape until a dimension is reached which is dependent on the thickness of the housing 11. When the camera is opened again into its picture-taking position, the chambers 19 and 20 and the scrolled film strip 21 therein return to their cylindrical shapes. This is possible because of the technically advanced properties of the film strip which may be an APS film (Advanced Photo System). It has been proved by several experiments that a loop-shaped chamber of about 20 mm in diameter and the included film strip can be pressed together to an oval shape of about 7 mm in height and that the film strip and the chamber will return to their original shapes when the pressure is removed. This feature is the basis for the realization of a camera of such a flat form. Regarding Figs. 4 and 5 of the drawing, one can recognize how the web 18 is designed to form the take-up chamber 20 and how the function of the same is. Within an area 24 of the take-up chamber 20, the web 18 has a width which is greater than the width of the remaining part 23 of the web 18. This area 24 is provided with a cut-out section 25 having a width which is a little greater than the width of the remaining part 23 of the web 18. The cut-out section 25 forms two arms 26, one on each side of said cut-out section 25, to which a tension spring 27 is connected each. The other end of the tension spring 27 is connected to the housing 11. In order to form the loop-shaped film take-up chamber 20 the remaining part 23 of the web 18 is guided through the cut-out section 25 and then led into the direction of the film feed chamber 19. In order to form the film feed chamber 19, the web 18 has an area of the same design as described for the take-up chamber 20. When a film strip 21 is fed from the film feed chamber 19 across the film gate 22 into the film take-up chamber 20, the growing scroll of the film strip will increase its outer diameter instead of lowering its inner diameter. To avoid a jam or squeeze of the film strip 21 inside the chamber 20, the same is able to increase in its outer diameter by stretching the tension spring 27 such that the circumference of the film take-up chamber increases very easily. This is caused by a radially effective pressure. When the film strip 21 is removed from the film transporting device, the film take-up chamber 20 returns to its original shape. Reference Numerals 10 Photographic camera 11 Housing 12 Front plate 12a, 12b Halves 13 Joint 13a, 13b Joint 14 Lens plate 15 Taking lens 16 Bellows 17 Guide rail 18 Web 19 Film feed chamber 20 Film take-up chamber 21 Film strip 22 Film gate 23 Remaining part of the web 24 Area 25 Cut-out section 26 Arms 27 Tension spring 28 Film advance member 29 Outside grip 30 Optical axis

Claims: Photographic camera (10) having a device for winding a film strip to form a cylindrical film roll, and a film take-up chamber (20) having a flexible arcuate film guide which allows the outside diameter of the film roll to increase, characterised by comprising: a housing (11) to which a front plate (12) is hinged and in which a lens plate (14) including a taking lens (15) is slidably guided in the direction of an optical axis (30), the front plate being movable between an open position in which the lens plate is in the picture-taking position and a closed position in which the thickness of the camera depends on the thickness of the housing a one-piece flexible web (18) which forms a loop-shaped film feed chamber (19) and a loop-shaped film take-up chamber (20), wherein said housing (11) has a thickness which is smaller than the diameter of said loop-shaped chambers (19, 20) measured in the direction of said optical axis (30) so that said flexible loop-shaped chambers (19, 20) and the included film strip (21) are pressed into an oval shape when said front plate (12) is in its closed position. Photographic camera according to claim 1, wherein a tension spring (27) is provided which, with its one end, is connected to at least one of the opposite ends of said web (18) and, with its other end, is fixed to said housing (11), whereby the diameter of said film take-up chamber (20) increases by stretching said tension spring (27) when said film strip (21) is fed into said take-up chamber (20). Photographic camera according to claim 1, wherein said tension spring (27) is connected to the free end of said web (18) adjacent to said film take-up chamber (20). Photographic camera according to claim 1, wherein within an area (24) of said film take-up chamber (20) and/or said film feed chamber (19) said web (18) has a width which is greater than the width of the remaining part (23) of said web (18), and wherein in said area (24) a cut-out section (25) is provided having a width greater than the width of said remaining part (23) of said web (18) forming two arms (26) on each side of said cut-out section (25) to which one of said tension springs (27) is connected each, and wherein said remaining part (23) of said web (18) is guided such that said loop-shaped chambers (19, 20) are formed. Photographic camera according to claim 1, wherein said front plate (12) is formed of two halves (12a and 12b) which are hinged at opposite sides of said housing (11). Photographic camera according to claims 1 and 5, wherein said lens plate (14) is connected to said housing (11) by a bellows (16) in a light-tight manner. Photographic camera according to claim 1, 5 and 6, wherein means (17) are provided for guidably connecting said lens plate (14) to said halves (12a, 12b), wherein said lens plate (14) when in its rest position is completely covered by said closed halves (12a, 12b) and wherein said lens plate (14) when in its picture-taking position is fixed when said halves are open. Photographic camera according to claim 1, wherein a film advance member (28) is translationally guided within said housing (11) and has an outside grip (29).

Inventors: EARLE ANTHONY, GLOVER EDWARD, EARLE, ANTHONY, GLOVER, EDWARD
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY
Application year: 1999
Main classification: G03B19
IPC codes: G03B17, G03B19