REWIND INTERLOCK FOR APS CAMERA

Abstract: The camera (10) of this invention preferably includes a rewind interlock (300) that prevents the double exposure of film (14). Preferably, the camera of this invention is an Advanced Photo System (APS) camera that employs APS film. Such APS film may be contained in a film cassette (16) that has a light lock door (23). The rewind interlock prevents thrusting or pulling a frame from the film cassette after that frame of film has been exposed and rewound into the film cassette. This prevents the accidental double exposure of a frame of film. In a preferred embodiment of this invention, the rewind interlock prevents thrusting or pulling film from a film cassette after all of the film has been rewound into the film cassette. The rewind interlock does this by preventing the film advancing mechanism (12) from being manipulated in a direction that advances film from the cassette after the exposed film has been rewound into the film cassette. The rewind interlock may be reset to permit the advancement of film from a film cassette by the removal of the film cassette from the camera.

Description: REWIND INTERLOCK FOR APS CAMERA Background of the Invention The camera of this invention preferably includes a rewind interlock that prevents accidental advancing of exposing film after it has been rewound into a film cassette. Preferably, the camera of this invention is a manual Advanced Photo System (APS) reusable camera. This application contains subject matter that is related to commonly assigned co-pending patent application serial no. 09/400,965 entitled "Camera With Combined Film Advance/Rewind Mechanism," which is hereby incoφorated by reference. Cameras typically have a film cassette compartment for receiving a film cassette, a film spool and a film path. The film spool is generally rotatably mounted to the camera and disposed in a film spool compartment on a side of the camera opposite the side that the film cassette compartment is disposed. The film path is defined by the region between the film cassette compartment and the film spool compartment and typically includes the film exposing area. Once a film cassette is loaded into the camera, film is typically loaded by moving the film out of the film cassette, and along the film path, and then winding the film around the film spool. As exposures are taken, the film is then moved from the film spool and the film path back into the film cassette. In order to load film around the film spool, motorized 35 mm. cameras typically have a motor that rotates the film spool to pull the film out of the film cassette, draw it across the film path and wind it around the film spool. Before loading the film, an exposed film leader extending from the 35 mm. film cassette has to be manually wrapped around the film spool. In order to rewind the film back into the film cassette after exposures are taken, the same motor or another motor rotates a spindle of the film cassette to pull the film back into the film cassette. Relatively recently, Advanced Photo System (APS) film has been developed. An APS film cassette does not have an exposed film leader, but rather has a light lock door for light sealing the film within the cassette. APS film is thinner than conventional 35 mm. film and unlike 35 mm. can be thrust from a cassette. In fact, APS film must be thrust from the cassette in order to initially move the film out of the cassette because it does not have an exposed film leader. In order to load APS film, the light lock door of the film cassette is opened and the film is thrust from the cassette by rotating a spindle of the film cassette. In one type of APS camera the film is loaded around the film spool prior to exposing the film. This includes thrusting the film across a film exposure area and around a film spool. In order to complete the loading process, the film is wound around the film spool. After loading is complete the first frame to be exposed rests in the film exposing area and the other frames are wrapped around the film spool. After exposure of a frame, the exposed frame is moved into the film cassette and the next frame to be exposed is moved from the film spool to the film exposing area. Other types of APS cameras do not "load" film as described above. Rather, in these other APS cameras the first frame of film is advanced from the cassette to the film exposing area. After exposure of this frame, the exposed frame is moved to the film spool and the next frame to be exposed is moved from the film cassette to the film exposing area. This process continues until all of the exposures have been taken. After which, the film is moved from the film spool across the film exposing area and back into the film cassette. In motorized APS cameras, a motor may be used to rotate the spindle of the film cassette and thrust the APS film from the cassette. Once the APS film has begun winding around the film spool, the film spool may be rotated by the same motor or a separate motor to completely wind the film around the film spool. It will be appreciated that since 35 mm. cameras do not thrust film and APS cameras need to thrust film out of the film cassette, mechanisms have to be developed to thrust APS film. Further, in manual type APS cameras, non-motorized mechanisms need to be developed to thrust APS film. This invention relates to an improved camera for thrusting APS film from and rewinding APS film into an APS film cassette that has a light lock door. This invention also relates to a camera that has an interlock that prevents a camera user from thrusting film from the film cassette, when film is to be rewound and rewinding film into the film cassette, when film is to be thrusted. Summary of the Invention The camera of this invention is preferably a manual reusable APS camera. However, it need not be this type of camera and features of this invention may be employed with other types of cameras. The camera of this invention may have a combined advance/rewind mechanism for advancing or thrusting film out of a film cassette and for winding film back into the film cassette. Further, the camera of this invention preferably includes a film cassette compartment, a film path and a film spool. The film cassette compartment defines an area within the camera for receiving a film cassette. Preferably, the film cassette compartment may receive an APS film cassette. The film spool is rotatably mounted to the camera, so that film from the film cassette may be wound around the film spool. Disposed between the film cassette compartment and the film spool is the film path. The film path also defines an exposure area in which the film is exposed to create images on the film. In one embodiment, after a film cassette is loaded into the camera, the leading edge of the film is moved from the film cassette along the film path and to the film spool, and the first frame of film is disposed within the film exposing area. After the first frame of film is exposed, that frame is advanced to the film spool and the next frame is advanced to the film exposing area. Operation of the camera continues in this fashion until all of the desired exposures are taken. After the film has been exposed and it is desired to remove the film cassette from the camera, the film is rewound into the film cassette by moving the film from the film spool along the film path and back into the film cassette. The combined advance rewind mechanism is rotatably mounted to the camera and may be coupled to a spindle of the film cassette. When rotated in a first direction, the combined film advance/rewind mechanism thrusts film out of the film cassette by rotating the film cassette spindle. The combined advance/rewind mechanism may also rotate the film spool when it is rotated in the first direction to pull film around the film spool after the film has been thrusted to the film spool. In comparison, when the combined advance/rewind mechanism is rotated in a second direction, the film cassette spindle is rotated in a second direction to wind film into the cassette and around the spindle of the cassette. A gear train may also be included within the camera that couples the combined film advance/rewind mechanism to the spindle of the film cassette and to the film spool. In order to load the film, the combined film advance/rewind mechanism is rotated in the first direction to rotate the spindle of the film cassette and to rotate the film spool. The rotation of the spindle causes the leading edge of the film to be thrust out of the film cassette and into the film path. As, the film enters the film path, the leading edge of the film crosses the film path and reaches the film spool, which is also rotating due to the rotation of the combined film advance/rewind mechanism. Rotation of the film spool pulls or winds the film around the film spool. Further rotation of the combined advance/rewind mechanism in the first direction winds the leading edge of the film onto the film spool. After each frame of film is exposed in the film exposing area, the film spool is rotated to pull the exposed frame of film around the film spool and to advance the next frame of film to be developed to the film exposing area. After the pictures have been taken with the camera, the combined film advance/rewind mechanism is rotated in a second or rewind direction. In this direction, the gear train couples the combined film advance and rewind mechanism to the spindle of the film cassette, but not the film spool. Thus, rotation of the film advance and rewind mechanism rotates the film spindle in a second direction to pull or rewind the film back into the film cassette. The combined film advance/rewind mechanism may further include an interlock that prevents movement of film either out of or into the film cassette when it is not desired to do so. This interlock prevents rotation of the combined film advance/rewind mechanism in the second or rewind direction when the interlock is in a first position. The interlock may also prevent rotation of the combined film advance/rewind mechanism in the first or advance direction to rewind film when the interlock is in the second position. Thus, this interlock prevents movement of the film in a direction opposite to that desired. In a preferred embodiment the interlock includes a retractable rewind crank that has a first position and a second position. When the rewind crank is fully rotated into its first position, the rewind crank fits within a groove of the combined film advance/rewind mechanism. The interlock may further include a spring mechanism and a slidable plate. This slidable plate is moved by the rotation of the retractable rewind crank between a first position and a second position. In its first position, a slidable plate prevents movement of the combined film advance and rewind mechanism in the second direction and in its second position a slidable plate prevents movement of the combined film advance and rewind mechanism in its first direction. The spring mechanism is preferably mounted to the combined film advance and rewind mechanism, so that it rotates with the combined film advance/rewind mechanism. The spring mechanism is engageble with a stationary support that is rigidly mounted to the camera to prevent rotation of the combined advance/rewind mechanism in either or both the first and the second direction depending on the position of the slideable plate. When the rewind crank and the slideable plate are in their respective first positions, the spring mechanism engages the stationary support to prevent rotation of the combined advance/rewind mechanism in its second or rewind direction. Movement of the rewind crank to its second position causes the slideable plate to move to its second position. The spring mechanism responds to movement of the slideable plate to engage the stationary support to prevent movement of the combined advance/rewind mechanism in its first direction. In addition, the spring mechanism responds to this movement of the slideable plate to disengage the stationary support to permit rotation of the combined advance/rewind mechanism in the second rewind direction. If the rewind crank is rotated to a third position, which includes any rotational position between its first and second positions, the slideable plate will move to disengage with the spring mechanism. Once disengaged, the spring mechanism will engage the stationary support to prevent rotation of the combined advance/rewind mechanism in both the first and the second directions. Thus, in order to advance film from the film cassette to the film spool, the rewind crank must be in the first position. Likewise, the rewind crank must be in the second position in order to rewind the film. Therefore, a camera user is prevented from moving film in the wrong direction and cannot move the film in the proper direction unless the rewind crank is positioned properly. As alluded to above, the camera of this invention preferably includes a gear train that couples the combined film advance/rewind mechanism to either or both the film cassette and the film spool. Preferably, the combined film advance/rewind mechanism is manually operated and the gear train transmits its driving force to either or both the spindle of the film cassette or the film spool. If the combined film/rewind mechanism is rotated in its first direction, the gear train couples the combined film advance/rewind mechanism to the spindle of the film cassette and to the film spool. When the film is to be loaded onto the film spool, the combined film advance/rewind mechanism is rotated in its first direction to thrust film out the film cassette into the film path and around the film spool. The film will be thrust from the film cassette until it is relatively taught within the film path. Once it is relatively taught, the gear train will disconnect the combined advance/rewind mechanism from the spindle of the film cassette. At this point, the combined advance/rewind mechanism will be coupled to the film spool, so that the film spool will rotate to pull film around the film spool when the combined advance/rewind mechanism is rotated in the first direction. This occurs because as is explained below, further rotation of the advance/rewind mechanism causes the spindle of the film cassette to become disengaged from the advance/rewind mechanism. This occurs because a portion of the gear train operates as a clutch and disconnects the mechanism from the spindle after the film begins to be wrapped around the film spool. Thus, further rotation of the advance/rewind mechanism rotates the film spool, but not the spindle of the film cassette, to pull film from the cassette to the film spool. In summary, film is moved from the cassette by first thrusting the film from the cassette and then pulling film from the cassette once the film is sufficiently taught within the film path. After an exposure has been taken and film is to be rewound into the film cassette, the combined film advance/rewind mechanism may be rotated in its second direction. When rotated in the second direction, the gear train decouples the combined film advance/rewind mechanism from the film spool. Therefore, rotation of the combined film advance/rewind mechanism will rotate only the spindle of the film cassette to pull and rewind film back into the film cassette. In order to decouple the combined film advance/rewind mechanism from the film spool when the combined film advance/rewind mechanism is rotated into the second direction, one of the gears of the gear train may be pivotably mounted on a pivot plate. Because it is pivotably mounted, rotation of the gear train, due to rotation of the combined film advance/rewind mechanism in the second direction, will push the pivotably mounted gear out of engagement with at least one of the other gears of the gear train. Once this pivotably mounted gear is out of engagement, the combined film advance/rewind mechanism is no longer coupled to the film spool and rotation of the combined film advance/rewind mechanism is not transmitted to the film spool. The camera of this invention may further include a rewind interlock that prevents double exposure of the film by advancing exposed film from the film cassette back into the film exposing area after the exposed film has been rewound into the film cassette. Because APS film can be thrust and is thrusted out of the film cassette, the potential exists that exposed rewound film can be thrust out of the film cassette and exposed again. If this occurs, a picture may be accidently destroyed. In order to prevent this occurrence, the camera of this invention may have a rewind interlock. The rewind interlock may include a rotatable pawl, a rotatable interlock lever and a rotatable wheel that is coupled to a film moving mechanism. The wheel may be part of the combined advance/rewind mechanism described above or a wheel that is coupled to any of a variety of film advance and rewind mechanisms. The wheel rotates in an advance direction when film is moved from the cassette to the film spool, and a rewind direction when the film is moved from the film spool to the film cassette. Disposed on an inner periphery of the wheel may be a notch, and disposed within a cavity defined by the inner periphery of the wheel may be the pawl. The pawl is preferably spring biased to rotate towards the inner periphery. The interlock lever is preferably rotatably mounted to the camera, and the pawl is rotatably mounted to the interlock lever, so that the pawl can rotate with the interlock lever and relative to the interlock lever. One end of the pawl may be angled for interaction with the notch to define the interlock. The pawl and the interlock lever preferably have a first position in which the pawl is disposed against the inner periphery of the wheel. While in the first position, the wheel can rotate in the advance direction and except when the notch contacts the pawl, the inner periphery of the wheel slides against the pawl as the wheel rotates. When the notch on the wheel engages the pawl, as the wheel is rotated in the advance direction, the notch pushes the pawl to rotate against the bias of the spring to permit the notch to be rotated past the pawl. Once the notch rotates past the pawl, the pawl is released and again rests against the inner periphery. In order to define the interlock, the wheel is rotated in the rewind direction. As the wheel is rotated in the rewind direction, film is being moved back into the film cassette. The inner periphery of the wheel slides along the pawl, until the notch contacts the pawl. Upon contacting the pawl in the rewind direction, the notch causes the pawl to rotate against the bias of the spring in a direction opposite to that which it rotates when the wheel is rotated in the advance direction. Once the notch rotates past the pawl in the rewind direction, the pawl is released and the spring causes the pawl to rotate to contact the inner periphery of the wheel. However, the pawl contacts the inner periphery in a second position, which is a rotated position relative to its first position. In this second position, an angled end of the pawl is disposed so that the notch cannot be rotated past the angled end when the wheel is rotated in the advance direction and the interlock is defined. In contrast, the wheel can still be rotated in the rewind direction because the notch can push the pawl to rotate out of its path when the wheel is rotated in the rewind direction. If the wheel is rotated in the advance direction with the pawl in the second position, the notch will contact the angled end of the pawl and become jammed, so that the wheel and the mechanism for moving the film cannot be manipulated further to move film from the film cassette and toward the film spool. The wheel can still be rotated in the rewind direction to rewind the film into the cassette. Since the interlock is created by rotating the wheel in the rewind direction, the interlock prevents advancing film after the film has been rewound and thereby prevents exposing the film twice. In order to reset the rewind interlock, the camera may have a slide that is coupled to the door that covers the film cassette compartment. Closing and opening of the door moves the slide because the slide is mechanically coupled to the door. As the slide moves, it either moves or releases the spring biased interlock lever to rotate. After the film has been rewound, the door of the film cassette compartment can be opened to remove the film cassette. Opening of this door, moves the slide to releases interlock lever to rotate due to the bias of the spring. When the interlock lever rotates, the attached pawl rotates with it away from the inner periphery of the wheel. As the pawl rotates with the interlock lever, the pawl also rotates relative to the interlock lever to a reset position. After a new film cassette is inserted into the film cassette compartment the film cassette compartment door is closed. Closing of the door of the film cassette compartment moves the slide to push the interlock lever against the bias of the spring to cause the interlock lever to rotate. Since the pawl is mounted to the interlock lever, the pawl rotates with the interlock lever to move the interlock lever to the first position, where the wheel can be rotated in the advance direction. Other features of this invention are provided below. Brief Description of the Drawings Figure 1 is a diagrammatical side view of a camera according to a preferred embodiment of this invention; Figure 2 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film being thrust out of the film cassette and into the film path; Figure 3 is a cross-section taken along line 3-3 of Figure 1; Figure 4 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film being advanced from the film cassette to the film spool; Figure 5 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film cassette and the film spool as the film is being advanced from the film cassette to the film spool; Figure 6 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film being wound around the film spool; Figure 7 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film cassette and the film spool as the film is being wound around the film spool; Figure 8 is a diagrammatical top view of the prefeπed embodiment of Figure 1 depicting the film being rewound from the film spool to the film cassette; Figure 9 is a diagrammatical top view of the preferred embodiment of Figure 1 depicting the film cassette and the film spool as the film is being rewound from the film spool to the film cassette; Figure 10 is an assembly drawing depicting a first prefeπed embodiment of a combined advance/rewind mechanism; Figure 11 is cross sectional taken along 11-11 of Figure 2; Figure 12 is a cross-section taken along line 12-12 of Figure 11; Figure 13 is a cross-section taken along line 13-13 of Figure 12; Figure 14 is a cross sectional view of the preferred embodiment of the combined advance/rewind mechanism of Figure 10 in a second position; Figure 15 is a cross-section taken along line 15-15 of Figure 14; Figure 16 is a top view assembly drawing of the embodiment of Figure 10 being assembled to a camera and a rewind interlock according to a prefeπed embodiment of this invention; Figures 17 and 17A are assembly drawings of the embodiment of Figure 10 and the rewind interlock of Figure 16; Figure 17B is a diagrammatical view of the embodiment of Figure 10, as the film cassette is being removed from the film cassette compartment; Figure 17C is a cross section taken along line 17C-17C of Figure 17B; Figure 17D is a diagrammatical view of the embodiment of Figure 10 with a film cassette inserted into the film cassette compartment; Figure 17E is a cross section taken along line 17E-17E of Figure 17D; Figure 17F is a diagrammatical end view of the embodiment of Figure 1 with the film cassette compartment door closed; Figure 17G is a diagrammatical end view of the embodiment of Figure 1 with the film cassette compartment door being opened; Figure 17H is a diagrammatical end view of the embodiment of Figure 1 with the film cassette compartment door being closed; Figure 18 is top view of the embodiment of the rewind interlock of Figure 16 in a first position; Figure 19 is a top view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being advanced; Figure 20 is a top view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 20A is a bottom view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 21 is another top view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 21 A is another bottom view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 22 is another top view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 22 A is another bottom view of the embodiment of the rewind interlock of Figure 16 depicting the operation of the rewind interlock when the film is being rewound; Figure 23 is a top view of the embodiment of the rewind interlock of Figure 16 when the rewind interlock is in a second position; Figure 23 A is a bottom view of the embodiment of the rewind interlock of Figure 16 when the rewind interlock is in a second position; Figure 24 illustrates the resetting of the rewind interlock of Figure 16 so that film can be advanced; Figure 25 is an assembly drawing of a combined advance/rewind mechanism according to a second prefeπed embodiment of this invention; Figure 26 is a cross section of the prefeπed embodiment of Figure 25 with the preferred embodiment in a first position; Figure 27 is a cross-section taken along line 27-27 of Figure 26; Figure 28 is a cross section of the prefeπed embodiment of Figure 25 with the prefeπed embodiment in a third position; Figure 29 is a cross-section taken along line 29-29 of Figure 28; Figure 30 is a cross section of the prefeπed embodiment of Figure 25 with the prefeπed embodiment in a second position; and Figure 31 is a cross-section taken along line 31-31 of Figure 30. Detailed Description of Preferred Embodiments The camera 10 of this invention preferably has a combined film advance and rewind mechanism 12 that may be used to advance or thrust film 14 from a film cassette 16 and rewind film 14 into the film cassette 16. Preferably, the camera 10 of this invention is an Advanced Photo System (APS) camera of the type that employs APS film 14 contained within an APS film cassette 16 that has a light lock door. However, various features of this invention may be employed with cameras that do not use APS film. In a preferred embodiment of this invention, the camera 10 may be a manual camera that does not employ a motor to move the film 14 into and out of a film cassette 16, but rather has a manually operated combined advance/rewind mechanism 12 within the camera 10 for moving the film 14. Further, the camera 10 is preferably a reusable APS camera 10. A reusable camera is intended to be reloaded with a film cassette after the film from one cassette has been exposed. A film cassette can be removed from a reusable camera and delivered to a film developer without at least partially destroying the camera. However, some features of this invention may be employed with a single-use APS camera 10. A single-use camera is one that is purchased with a film cassette 16 loaded into the camera 10 and the film 14 loaded, so that the camera 10 is ready for picture taking. Single-use cameras are intended to be given to a film developer for removing the film cassette 16 and developing the film 14; they are not intended to be reloaded with film 14 by the camera purchaser. By way of overview, the camera 10 of this invention includes a combined advance/rewind mechanism 12 for manually thrusting film 14 from a film cartridge to load the film 14 and for manually pulling the film 14 to rewind the film 14 into the film cassette 16 after an exposure has been taken. Two embodiments of the combined advance/rewind mechanism are described below. Figures 1-9 illustrate a film 14 loading sequence and a rewinding sequence with both of the embodiments of the combined advance/rewind mechanism of this invention. A first prefeπed embodiment of the combined advance/rewind mechanism 12 is illustrated in Figures 10-17, and Figures 25-31 illustrate a second prefeπed embodiment of the combined advance/rewind mechanism 12. The camera of this invention may also include a rewind interlock, an embodiment of which is depicted in Figures 16-24. The rewind interlock prevents double exposure of the film. As described in more detail below, in the embodiment shown, the rewind interlock prevents advancing film and then exposing it after it has been exposed and rewound into the film cassette. Both embodiments of the camera 10 of this invention may have a film cassette compartment 18 for receiving a film cassette 16 and a film spool compartment 20, as shown diagrammatically in Figure 1. Rotatably mounted within the film spool compartment 20 is a film spool 22 onto which film 14 from a film cassette 16 may be wound. The film spool 22 may have a rubber sleeve mounted about its exterior. A film path 21, shown diagrammatically in Figure 2, may be defined between the film cassette compartment 18 and the film spool compartment 20. Film 14 travels along the film path 21 between the film cassette compartment 18 and the film spool compartment 20. Exposure of the film 14 occurs while it is in the film path 21. In a prefeπed embodiment, the camera 10 includes a combined film advance rewind mechanism 12, a gear train 24 and a film interlock 26. The gear train 24 is best illustrated in Figures 1-9. The function of the gear train 24 is to couple the combined advance/rewind mechanism 12 to the film spool 22 and/or the spindle 27 of the film cassette, so that manipulation of the combined advance/rewind mechanism 12 will drive the film spool 22 and/or the spindle of the film cassette 16 to rotate at a desired speed to either advance or rewind the film. Although a variety of gear trains 24 may be used to couple the combined advance/rewind mechanism 12 to the film spool 22, a prefeπed embodiment is illustrated in Figures 1-9 and described in detail below. By way of overview, with the camera 10 of this invention an APS film cassette 16 may be light sealed within the camera 10 and the light lock door 23 of the film cassette 16, shown diagrammatically in Figure 3, may be opened. Following this, the film 14 may be manually thrust out of the film cassette 16 and into the film path, as shown diagrammatically in Figures 2 and 3, with the combined film advance/rewind mechanism 12. The film may be further thrust until the leading edge of the film reaches the film spool, as shown diagrammatically in Figures 4 and 5. As is explained below, once the leading edge of the film begins to be wrapped around the film spool, the film is advanced from the film cassette to the film spool by either the rotation of the film spool which is driven by the combined advance/rewind mechanism or by the rotation of the film cassette spindle. In the embodiment shown, the leading edge of the film is advanced to the film spool and the first frame of film is advanced to the film exposing area. After this, pictures are taken and the frame of exposed film is advanced to the film spool and the next frame is advanced from the film cassette to the film exposing area. This process continues until all of the desired pictures are taken. As is explained below, the combined advance/rewind mechanism 12 may be used to manually drive the film spool 22 to pull the film 14 from the film cassette 16 and wind the film 14 around the film spool 22, as depicted in Figures 4-7 after each exposure. In order to rewind the film 14 into the film cassette after the desired number of pictures have been taken, the combined advance/rewind mechanism 12 is manipulated to rotate the spindle of the film cassette 16 and pull the film 14 into the film cassette 16, as shown in Figure 8. A description of the gear train 24 and two embodiments of the combined advance/rewind mechanism 12 is provided below. A description of the film loading sequence and the rewinding of film into the film cassette after the film has been exposed is also provided. Further, a description of the rewind interlock that may be used with or without either of the embodiments is also provided. FIRST EMBODIMENT OF THE COMBINED ADVANCE/REWIND MECHANISM As alluded to above, Figures 10-17 depict a first prefeπed embodiment of a combined advance/rewind mechanism 12 of this invention. The combined advance/rewind mechanism of this invention enables the film to be advanced and rewound with the same mechanism. The combined advance/rewind mechanism 12 includes an interlock 26, a rewind crank 28 and an advance wheel 30. The advance wheel 30 is rotatably mounted to the camera 10 and includes a segmented portion 32 for engagement by a camera user's thumb, as best shown in Figure 17. Because of this, the advance wheel 30 may be refeπed to as a "thumb wheel." As described below depending upon the position of the rewind crank 28, the thumb wheel can be rotated in either the counter clockwise direction, as shown in Figure 2, to advance film 14 from the film cassette 16 to the film spool 22, or in the clockwise direction, as viewed in Figure 8, to rewind film 14 from the film spool 22 into the film cassette 16. In addition to having an advance wheel 30, the combined film advance/rewind mechanism 12 may include a body 34 and a cap 36. In the embodiment illustrated in Figure 10, the body 34 and the cap 36 are formed integrally from a plastic molding process. The driving gear 204, discussed below, is in this embodiment integrally formed with the combined advance/rewind mechanism, but it need not be integrally formed and may be a separate piece. The rewind crank 28 is preferably pivotably mounted to the combined advance/rewind mechanisml2 as shown in Figure 10. A pin 38 may extend through a bore 40 defined with the rewind crank 28 and the cap 36, so that the rewind crank 28 may be pivoted about the pin 38 between a first position and a second position. In a first position, the rewind crank 28 may be rotated to fit within a groove 46 defined within the combined advance/rewind mechanism 12, as shown in Figure 12. In its second position, the rewind crank is fully rotated, out of the groove, as best shown in Figure 14. With the rewind crank 28 in this first position, the thumb wheel 30 may be rotated to advance or thrust film 14 from the film cassette 16 into the film path and to the film spool 22, but may not be rotated to rewind film 14 from the film path into the film cassette 16. Conversely, in the second position the thumb wheel 30 may be rotated to rewind film 14 from the film spool 22 to the film cassette 16, but may not be rotated to thrust film from the film cassette 16 into the film path. The rewind crank 28 interfaces with the interlock 26 described below to control the direction of rotation of the thumb wheel 30. If the rewind crank 28 is rotated to a third position, which includes any position between its first and second position, the interlock 26 will prevent rotation of the thumb wheel 30 in either direction, as shown in Figures 28 and 29. Thus, with the rewind crank 28 in this third position, the film 14 cannot be advanced nor can it be rewound. The rewind crank 28 may have a tab 42 that extends at an angle to the handle 44 of the rewind crank 28, so that a camera user may relatively easily rotate the rewind crank 28 from the first position depicted in Figure 12 to the second position, shown in Figure 14. Preferably, the handle 44 of the rewind crank 28, shown in Figure 10, is held in the groove 46 defined within the cap 36 of the combined advance/rewind mechanism 12 by a frictional force created between the handle 44 and detents or the like extending from the combined advance/rewind mechanism 12 into the groove 46. As is best shown in Figure 10, the interlock 26 preferably includes a slidable plate 48, a spring mechanism 50 and a stationary support 52. The slidable plate 48 is preferably slidable between a first position and a second position. Further, the slidable plate 48 preferably has a first raised portion 54 and a second raised portion 56. The first raised portion 54 is preferably of a height that is greater than the height of the second raised portion 56, as is best illustrated in Figure 12. The first raised portion 54 may have a lip 58 that fits within a space defined between an end 57 of the rewind crank 28 and an inner surface 59 of the body 34 of the combined advance/rewind mechanism 12, as is also shown in Figure 12. The lip 58 can be engaged by the end of the rewind crank 28, so that the slidable plate 48 may be moved between the first position, illustrated in Figures 12 and 13, and its second position, depicted in Figures 14 and 15. These raised portions 54, 56 interface with the spring mechanism 50 and the rewind crank 28, as is described in more detail below, to prevent the rotation of the advance wheel 30 in either the rewind direction or the advance direction depending upon the position of the rewind crank 28. The slidable plate 48 may further have a first engaging surface 60 and a second engaging surface 62, as shown in Figures 10, 13 and 15. Each of these engaging surfaces 60, 62 is for engaging one of the springs 64 of the spring mechanism 50, as is described further below. The stationary support 52 preferably has a circular portion 66 extending from the camera body. This circular portion 66 is preferably integrally formed with the camera body. However, the stationary support 52 may be a separate piece from the camera body and may be attached to the camera body with a variety of fastening mechanisms. The stationary support 52 may further include a circular plate 68 that has a plurality of teeth 69 extending from its periphery. These teeth 69 interface with the spring mechanism 50 described below to control the direction of rotation of the combined advance/rewind mechanism 12. The circular portion 66 of the stationary support 52 may have a plurality of cylinders 69a extending from its upper surface. Disposed within the circular plate 68 may be a plurality of holes 69b that are placed within the circular plate 68 to coπespond to the cylinders 69a extending from the circular portion 66. The cylinders 69a may be press fit into the holes 69b to attach the circular portion 66 to the circular plate 68 in an interference fit. When attached to the circular portion 66, the circular plate 68 is rigidly affixed to the body of the camera 10, so that it cannot rotate. Further, the circular plate 68 and the circular portion 66 may both have an aperture 70 for receiving a pin 72 or rivet, as shown in Figures 10 and 11. The pin 72 may be placed through the apertures 70 to further affix the circular plate 68 to the circular portion 66. The pin 72 may have a head that prevents the circular plate 68 from becoming dislodged from the circular portion 66. Depicted in Figure 10 is a spring mechanism 50 according to a prefeπed embodiment of this invention. The spring mechanism 50 may be formed from plastic or from a stamping process. Disposed within the spring mechanism 50 may be an aperture 74 for receiving a pin 76. The pin 76 may be placed through the aperture 74 and into a cavity 77 within the combined advance/rewind mechanism 12 to affix the spring mechanism 50 to the combined advance/rewind mechanism 12, as is best shown in Figures 10 and 11. Because the spring mechanism 50 is attached to the body of the combined advance/rewind mechanism 12, the spring mechanism 50 rotates with the advance wheel 30. In contrast, the stationary support 52 including the circular portion 66 and the circular plate 68 are affixed to the camera body and do not rotate with the combined advance/rewind mechanism 12. Extending from the spring mechanism 50 may be a first spring 78 and a second spring 80. In the prefeπed embodiment of Figures 10-15, the first and the second springs 78, 80 are leaf springs. Further, each of the leaf springs are preferably biased in opposing directions. The first leaf spring 78 is preferably biased to rotate clockwise as viewed in Figure 10, and the second spring 80 is preferably biased to rotate counter clockwise as viewed in Figures 10 and 13. As described in further detail below, the first and second springs 78, 80 are engageable with the teeth 69 of the circular plate 68 to prevent rotation of the combined advance/rewind mechanism 12 in either the rewind direction or the advance direction depending on the position of the rewind crank 28. A rivet 82 or other fastening mechanism may be used to fasten the body 34 of the combined advance/rewind mechanism 12 to the camera 10. A hole 84 may be disposed within the body, and preferably the center of the body of the combined advance/rewind mechanism 12, for receiving the rivet 82. Another hole 86 may be disposed within the center of the slideable plate 48, the circular plate 66 and the circular portion 68, so that the rivet 82 may be inserted through each of these holes to fasten the body of the combined advance/rewind mechanism 12 to the camera 10, as is best shown in Figures 10 and 11. When fastened to the camera, the combined advance/rewind mechanism 12, the attached spring mechanism and the slidable plate are free to move with respect to the rivet 82. In contrast, the circular plate 68 and circular portion 66 are fixed and do not rotate. Figures 16, 17, and 17A best illustrate the assembly of the combined advance/rewind mechanism. As shown the combined advance/rewind mechanism is mounted upon the stationary support 52. Once mounted upon the stationary support 52, the combined advance/rewind mechanism rotates relative the stationary support 52. Figures 16 and 17 also depict aspects of the rewind interlock which are discussed below, and other aspects of a camera that may be employed with this invention that are described is commonly assigned co-pending United States Patent Application Serial No. 09/400,963, entitled "APS Camera For Ensuring The Cassette Indicator Is In The Parked Position," which is hereby incoφorated by reference. Figures 12 and 13 depict the combined advance/rewind mechanism 12 in a first position or a film advance position. In the film advance position, the thumb wheel 30 cannot be rotated in the rewind direction and film 14 cannot be rewound into the cassette 16. Rather, the thumb wheel 30 can be rotated in the advance direction to move film 14 from the film cassette 16 to the film spool 22. The interlock 26, formed in part by the springs 78, 80, prevents rotation of the thumb wheel 30 in the rewind direction, as described below. In contrast to Figure 12, Figures 14 and 15 depicts the combined advance/rewind mechanism 12 in the second or rewind position. Because of the interlock, film 14 can be rewound into the film cassette 16, but cannot be advanced from the film cassette when the advance/rewind mechanism is in the second position. Further operation of this embodiment is provided below, as is a description of another prefeπed embodiment of the combined advance/rewind mechanism and the interaction of both of these mechanisms with the film spool and the film cassette. OPERATION OF THE COMBINED ADVANCE/REWIND MECHANISM As shown in Figure 12, the rewind crank 28 is in its first position in which it is rotated fully into the groove 46 of the combined advance/rewind mechanism 12. In addition, the slidable plate 48 is in its first position. As is best shown in Figure 12, the lip 58 of the first raised portion 54 fits between the inner surface of the combined advance/rewind mechanism 12 and the rewind crank 28 in this first position. The first spring 78 of the spring mechanism 50 is held by the first engaging surface 60 of the slidable plate 48, so that the first spring 78 cannot engage the teeth 69 of the stationary circular plate 68, as shown in Figure 13. Because the first spring 78 is not engaged with the teeth of the circular plate 68, the combined advance/rewind mechanism 12 can rotate in the counterclockwise or advance direction to move film 14 from the film cassette 16 to the film spool 22. As is further depicted in Figure 13, the second engaging surface 62 of the slidable plate 48 does not engage the second spring 80 while the rewind crank 28 and the slidable plate 48 are in their respective first positions. Because, the second spring 80 is biased towards the teeth of the stationary support, the second spring rotates to engage one of the teeth of the circular plate 68, as is best shown in Figure 13. This prevents rotation of the advance wheel 30 in the clockwise or rewind direction, as shown in Figure 13, because the second spring 80 is engaged between two of the teeth 69 of the stationary circular plate 68. Thus, with the rewind crank 28 and the slidable plate 48 in the first position, the interlock 26 is formed that prevents rotation of the combined advance/rewind mechanism 12 in the rewind direction to move film 14 from the film spool 22 to the film cassette 16. However, rotation in the counterclockwise or advance direction is permitted. As shown in Figure 14, the rewind crank 28 may be rotated about the pivot pin 38 from its first position to its second position. When the rewind crank 28 is rotated, the end of the rewind crank 28 contacts the lip 58 of the slidable plate 48 and pushes the lip 58 of the slidable plate 48. The slidable plate 48 moves in response to the movement of the rewind crank 28 from its first position to its second position. As the slidable plate 48 moves, the first engaging surface 60 releases the first spring 78. Once released, the first spring 78 moves in between two of the teeth 69 of the circular plate 68. This prevents rotation of the combined advance/rewind mechanism 12 in the counter clockwise or advance direction. Furthermore, when the slidable plate 48 moves to its second position, the second engaging surface 62 of the slidable plate 48 contacts the second spring 80 and pushes the second spring 80 out of engagement with the teeth 69 of the circular plate 68, as is best shown in Figure 15. Once the second spring 80 is out of engagement with the teeth 69 of the circular plate 68, the combined advance/rewind mechanism 12 is free to rotate in the clockwise or rewind direction. Movement of the slidable plate 48 from the second position is inhibited by the crank 28, as shown in Figure 14, until the crank is rotated out of its second position. Thus, with the rewind crank 28 in the second position, an interlock 26 is defined that prevents the camera 10 user from advancing the film 14 out of the film cassette 16 and into the film path 21. It will be appreciated that the slidable plate 48 is preferably of dimensions, such that if the rewind crank 28 is in its third position, any rotational position between its first and its second position, the slidable plate 48 will release both the first and the second springs 78, 80. In this position, neither of the engaging surfaces 60, 62 contact the first and the second springs 78, 80. Therefore, both the first and the second springs 78, 80 rotate in between teeth 69 of the circular portion 66 of the stationary support 52. Since both of the springs 78, 80 are engaged with the circular portion 66, rotation of the combined advance/rewind mechanism 12 in both the rewind and the advance directions is inhibited. The interlock 26, therefore, provides an interlock 26 to prevent the camera user from rewinding or advancing film 14 unless the rewind crank 28 is in the proper position. If the rewind crank 28 is in the third position, rotation of the advance wheel 30 in either direction is inhibited by the interlock. Further, when the rewind crank 28 is in the first position, rotation of the advance wheel 30 in the rewind direction is prevented, and when the rewind crank is in the second position, rotation of the advance wheel 30 in the advance direction is prevented. SECOND EMBODIMENT OF COMBINED ADVANCED/REWIND MECHANISM A second embodiment of the combined advance/rewind mechanism 12 is depicted in Figures 25-31. This second embodiment also includes a rewind crank 28 that is pivotably mounted to a body of the combined advance/rewind mechanism 12 with a pivot pin 38 or the like. Similar to the rewind crank 28 described above, the rewind crank 28 may have a first position in which it is rotated into a groove 46 defined within the cap 36 of the combined advance/rewind mechanism 12, as shown in Figure 26 and a second position, as shown in Figure 30, in which the rewind crank 28 is fully rotated out of the groove 46. The rewind crank 28 may have a third position, that includes any rotational position between the first and the second positions. One such position is exhibited in Figure 28. A stationary support 52 is also provided. In this embodiment, the stationary support 52 has a periphery around which a plurality of teeth 69 are disposed. The stationary support 52 is rigidly affixed to the camera 10; it may be molded with the body of the camera 10 or affixed in another manner. A slidable plate 48 is also provided in this embodiment. The slidable plate 48 is also moveable between a first position and a second position in response to manipulation of the rewind crank 28 from its first position to its second position. Further, the slidable plate 48 also defines part of the interlock 26 that prevents rewinding film 14 when the rewind crank 28 is in the first position, and advancing film 14 when the rewind crank 28 is in the second position. The slidable plate 48 may further have a first and a second engaging surfaces 60, 62 for respectively engaging a spring biased first pawl 88 and a spring biased second pawl 90 of the spring mechanism 50. In this embodiment the first and the second engaging surfaces 60, 62 are not defined on raised portions of the slidable plate, but rather on the first and the second laterally extending portions 92, 94. The slidable plate 48 may further have a lip 58 for interfacing with an end of the rewind crank 28, so that as the rewind crank 28 moves between its first and second positions, the slidable plate 48 moves between its first and second positions. In this embodiment the combined advance/rewind mechanism 12 is not integrally formed with the driving gear 204 and includes an advance wheel 30 and a cap 36. The driving gear 204 may be coupled to the cap 36 with the first and the second portions 30a, 30b extending upward from the driving gear 204. The cap 36 may have an under surface that is shaped for receiving the upwardly extending portions of the driving gear 204. Adhesives or other mechanical means may be used to join the driving gear 204 to the cap. When attached together, the driving gear 204 fits over the stationary support 52 and under the cap 36, as best understood with reference to Figures 25 and 26. The driving gear 204 may be integrally formed with the cap 36. For example, molded plastic could be used to form an integral driving gear 204 and cap 36. In this embodiment, the spring mechanism 50 includes a first pawl 88, a second pawl 90 and a spring 95a. Rivets 95b or the like maybe used to fasten each of the pawls 88, 90 and the spring 95a to the underside of the cap 36, as shown in Figures 25 -27. In this embodiment, the spring 95a is preferably a wound piece of metal that is wound about one of the rivets 95b. The spring 95a has a first member 96 that pushes on the first pawl 88 and a second member 98 that pushes on the second pawl 90. Each of these members 96, 98 biases the respective pawl 88, 90 to rotate towards the teeth 69 of the stationary support 52, as shown in Figure 18. The cap 36 and the stationary support 52 may have a hole 100 for receiving a pin or rivet (not shown) for connecting the cap 36, the stationary support 52 and the advance wheel 30 together, as shown in Figures 25 and 26. These holes 100 are preferably in the respective geometric centers of these elements. This second embodiment operates similar to the first embodiment described above. An interlock 26 is defined by the rewind crank 28, the spring mechanism 50, the stationary support 52 and the slidable plate 48 that prevents advancing film 14 from the film cassette 16 unless the rewind crank 28 is rotated into the first position with the groove 46 of the cap 36, as shown in Figure 26 and rewinding film 14 into the film cassette 16 unless the rewind crank 28 is rotated to the second position, as shown in Figure 30. Figure 26 depicts the rewind crank 28 fully rotated into the groove 46 of the cap 36, the first position of the rewind crank 28. In this position, the slidable plate 48 cannot move because the lip 58 of the slidable plate 48 is prevented from moving by the crank 28, as shown in Figure 26. As shown, the slidable plate 48 is in its first position, and holds the first pawl 88 and the first member 96 of the spring mechanism 50 against spring pressure out of engagement with the teeth 69 of the stationary support 52. The second member 98 of the spring mechanism 50 is however free to rotate due to the bias of the spring and the second pawl 90 engages the teeth of the stationary support 52. This prevents the advance wheel 30 from being rotated in the counterclockwise direction, as shown in Figure 27 (the clockwise direction as shown in Figures 2-8) to rewind film 14 into the film cassette 16. In this position, the advance wheel 30 can be rotated counterclockwise, as shown in Figures 2-8, to advance film 14 from the film cassette 16 to a film spool 22. In order to rewind film 14, the rewind crank 28 is rotated upward from its first position of Figure 26 to its second position of Figure 30. As the rewind crank 28 rotates upward, the end of the rewind crank 28 pushes on the lip 58 of the slidable plate 48 and pushes the slidable plate 48 to move from its first position to its second position. In its second position, the second engaging surface 62 of the slidable plate 48 pushes the second pawl 90 and the second member 98 of the spring mechanism 50 against the bias of the spring 95a out of engagement with the teeth 69 of the stationary support 52. Furthermore, the slidable plate 48 releases the first member 96 of the spring mechanism 50. Once released, the first member 96 moves due to the force of the spring 95a into engagement with the teeth 69 of the stationary support 52, as shown in Figure 31. In this position, the first member of the spring mechanism 50 inhibits movement of the advance wheel 30 in the clockwise or advance direction, as shown in Figure 31 (the counterclockwise direction as shown in Figures 2-9). However, the advance wheel 30 is free to rotate in the counterclockwise or rewind direction. Thus, an interlock 26 is defined which prevents the rotation of the advance wheel 30 in the advance direction to move film 14 from film cassette 16 when the rewind crank 28 is in the second or rewind position. If the rewind crank 28 is in the third position, as shown in Figure 28, the end of the rewind crank 28 moves the slidable plate 48 from its first position to a third position. In its third position, the slidable plate 48 releases the first member 96 of the spring member so that the first pawl 80 engages the teeth of the stationary support 52, as shown in Figure 29. Additionally, in its third position, the slidable plate 48 is not moved far enough to move push the second pawl 90 and the second member 98 of the spring mechanism 50 out of engagement with the teeth 69 of the stationary support 52. Thus, in this position both the first and the second members 96, 98 of the spring mechanism 50 are engaged with the teeth 69 of the stationary support 52. The first member 96 inhibits rotation of the advance wheel 30 in the advance direction, and the second member 98 inhibits rotation of the advance wheel 30 in the rewind direction. Therefore, with the rewind crank 28 in its third position, the advance wheel 30 cannot be manipulated to move the film 14 into or out of the film cassette 16. This interlock 26 prevents the camera user from accidently moving the film 14 in an undesired direction. GEAR TRAIN In the embodiment depicted in Figures 1 and 2, the gear train 24 includes a plurality of gears including, a film cassette gear 200, a film spool gear 202 and a driving gear 204. This gear train may be employed with either of the embodiments of the combined advance/rewind mechanism described above. Although the plurality of gears may be designed to have any number of gears, the embodiment depicted has eleven gears (gears 206-224) disposed between the driving gear 204 and the film spool gear 202. The driving gear 204 is rotatably mounted to the camera 10, so that it rotates with the advance wheel 30 in the same direction as the advance wheel 30. Further, the film cassette gear 200 is rotatably mounted to the camera 10 and selectively connectable to gear 206 and gear 208. The film cassette gear 200 is also connectable to a spindle 27 of the film cassette 16 by shaft 201, shown in Figure 1, so that rotation of the film cassette gear 200 causes rotation of the spindle 27 and movement of film 14 either into or out of the film 14 cassette 16 depending upon the direction of rotation of thumb wheel 30. Gear 210 is coupled to the driving gear 204, so that gear 210 rotates in response to rotation of the driving gear 204 by the combined advance/rewind mechanism 12 in the opposite direction of the driving gear 204. Gear 212 is preferably mounted on a common shaft with gear 210, as best seen in Figure 1, so that gears 210 and 212 rotate in the same direction. Gears 206 and 208 are mounted at an elevation below gear 210 and the driving gear 204 and at the elevation of gear 212 and the film cassette gear 200, so that they can engage gear 212 and the film cassette gear 200, as best seen in Figure 1. Gear 212 couples gears 206 and 208 to the combined advance/rewind mechanism 12, so that rotation of the combined advance/rewind mechanism 12 drives either gear 206 and 208 to rotate. Preferably, gears 206 and 208 are smaller in diameter than the combined advance/rewind mechanism 12 and gear 210, so that gears 206 and 208 provide the appropriate increase in rotational speed between the combined advance/rewind mechanism 12 and gear 212. Gears 206 and 208 are pivotably mounted to the camera 10, so that they can pivot depending upon the direction of rotation of gear 212 and the combined advance/rewind mechanism 12. They may be mounted on a plate 230, shown diagrammatically, that is pivotably mounted to the camera 10 to rotate about the center of gears 210 and 212, and spring biased by a spring 231 so that the gear 208 is engaged with the film cassette gear 200 and the gear 206 is not. The spring 231 is connected to the plate 230 proximal to the gear 208, and the spring's end that is proximal to the gear 212 is not fixed. The spring 231 provides a relatively small drag force that prevents the plate 230 from rotating when gears 206 and 208 are not being driven, so that they do not move around in the camera due to gravity or mechanical forces. The force applied by spring 231 is large enough to prevent random movement of gears 206 and 208, but small enough so an not to impede rotation of gear 200. As is described in more detail below, gears 206 and 208 operate as a free wheeling clutch. If the combined advance/rewind mechanism 12 is rotated counter clockwise, the film advance direction, as viewed in Figure 2, the drive gear 204 will cause gear 210 and gear 212 to rotate clockwise. Gear 212 will push gear 206 to pivot on the pivot plate 230 against the bias of spring 231 , so that gear 206 is driven out of engagement with the film cassette gear 200. In contrast, since gear 208 is mounted on the pivot plate 230 with gear 206, the rotation of gear 212 causes gear 208 to pivot into engagement with the film cassette gear 200. In this position, the film cassette gear 200 is driven in the clockwise direction by gear 208 to thrust film. Conversely, if the combined advance/rewind mechanism is rotated in the clockwise or rewind direction, gear 208 will be driven out of engagement with the film cassette gear 200, and gear 206 is released to move into engagement with the film cassette gear 200 to rewind the film into the film cassette. Gear 212 is coupled to gear 214, and gear 216 is mounted on a common shaft with gear 214, as best seen in Figures 1 and 2. Gear 216 is coupled to gear 218, which is coupled to gear 220. Gears 214 and 216 rotate in the same direction to transmit the driving force from the combined advance/rewind mechanism to gears 218 and 220 Gears 218 and 220 preferably have the same diameter and number of teeth and therefore, serve as idler gears. Gear 222 is coupled to gear 220, and is also pivotably mounted to the camera 10 on a pivot plate or other movable mechanism, so that it may be coupled to and decoupled from gear 224 depending upon the rotation of the combined advance/rewind mechanism 12. Gear 224 is coupled to the film spool gear 202 that drives the film spool 22 to rotate. A spring (not shown) similar to spring 231 can also be used to bias gear 224 to prevent it from moving due to gravity or other mechanical forces. The force applied by such a spring would be small enough so as not to impede rotation of the gear train. Gear 222 moves between a first and a second position in response to the direction of rotation of the combined advance/rewind mechanism 12. When the combined advance/rewind mechanism is rotated in the advance direction, gear 220 exerts a force on gear 222 to pivot gear 222 on its pivot plate to a first position shown in Figure 2. In this first position, gear 222 is coupled to gear 224, so that gears 222 and 224 couple the combined advance/rewind mechanism 12 to the film spool gear 202. While in this first position, manipulation of the combined advance/rewind mechanism 12 will cause rotation of the film spool gear 202 and therefore, rotation of the film spool 22 in a direction that pulls film around the film spool 22. In contrast, if the combined advance/rewind mechanism is rotated in the rewind direction, gear 220 is rotated in the opposite direction and exerts a force on gear 220 to pivot gear 222 on its pivot plate to a second position, as shown in Figure 8. While in this second position, gear 222 is decoupled from gear 224. Thus, while gear 222 is in its second position, the combined advance/rewind mechanism 12 is decoupled from the film spool gear 202 and manipulation of the combined advance/rewind mechanism 12 will not drive the film spool 22 to rotate. Depending on the amount of film that is wrapped around the film spool and the tension of the film, the film will be either thrust from the film cassette by the rotation of the cassette spindle or pulled from the film cassette by the rotation of the film spool when the advance/rewind mechanism is rotated in the counterclockwise or advance direction. In order to move the leading edge of the film out of the film cassette after the initial loading of a film cassette into the camera, the film is thrust from the film cassette and into the film exposing area. During advancement of film, gear 212 drives gear 208 to drive the film cassette gear 200 to thrust film from the film cassette. In addition, gear 212 drives the film spool gear 202 to rotate. This occurs because when the combined advance/rewind mechanism 12 is rotated counterclockwise or in the advance direction, gear 220 exerts a force on gear 222 due to the direction of rotation of gear 220 that urges gear 222 towards gear 224 to couple gear 222 to gear 224 to rotate the film spool gear 202. Thus, as film is being initially thrust from the film cassette, both the film spindle and the film spool are being driven. Because the film is initially wrapped around the film spindle and not the film spool, initial movement of the film from the film cassette is by thrusting the film due to the rotation of the film spindle. As described, rotation of the combined advance/rewind mechanism in the advance direction rotates the film cassette spindle and the film spool. Rotation of the film cassette spindle will thrust film from the film cassette and rotation of the film spool will pull film from the film cassette. Since both the film cassette spindle and the film spool can be rotated by the combined advance/rewind mechanism, whether the film is being thrust or pulled when the film is being advanced depends upon several factors, including whether the film is wrapped around the film spool, the relative speeds of rotation of the film spindle and the film spool and whether the film within the film path and the film cassette is relatively taught. Because of the pads 22a, any film wrapped around the film spool is wrapped relatively tightly around the film spool. The film spindle does not have pads to maintain the film tightly wrapped around the film spindle. Whether the film around the film spindle and within the film path is relatively taught or is under tension is dependent upon several factors, including the speed at which the film spindle and the film spool rotate and forces applied on the film within the film path, such as a force applied by a film sensor or metering finger used to count the frames of film that have been exposed and friction exerted on the film by the components that make up the film path. Since just after loading a film cassette the film is not wrapped around the film spool, the film will be thrust when the combined advance/rewind mechanism is initially rotated in the advance direction. Because the film is not wrapped tightly around the spindle of the film cassette, the film is not under tension and is relatively slack as the leading edge of the film is initially thrust from the film cassette. The thrusted film wraps around the film spool 22. The point of change over from thrusting to pulling occurs as the film within the film path and around the film spool becomes relatively taught and the film is pulled faster than it is thrust. The film is pulled rather than thrust, because of the speed differential between the rotation of the film spool and the spindle of the film cassette due to the gear train and the effective diameter of the film spool and the film spindle due to the respective amount of film wrapped around the film spool and the film spindle. The speed differential causes gear 208 to swing out of engagement with the film cassette gear 200, so that the combined advance/rewind mechanism is decoupled from the film cassette spindle. Gear 206 remains out of engagement with the film cassette gear 200, as the advance wheel is rotated in the advance direction. Continued rotation of the combined advance/rewind mechanism causes rotation of the film spool gear 202 and the film spool 22 which pulls the film from the film cassette and wraps the film around the film spool 22. Depending on the linear speed differential between the film cassette and the film spindle, the film may be either thrust or pulled, as it is advanced. In one embodiment, the film is thrust when advancing the first few frames because the linear speed of thrusting due to rotation of the film spindle is greater than the linear speed of pulling due to rotation of the film spool. After the first few frames have been advanced in this embodiment, as more film is wrapped around the film spool, the effective diameter of the film spool increases as does the linear speed of pulling. Once the linear speed of pulling is greater than the linear speed of thrusting, the film is pulled rather than thrust as it is advanced. If the combined advance/rewind mechanism 12 is rotated in the clockwise or rewind direction, gear 212 will push gear 206 against the bias of spring 231 into engagement with the film cassette gear 200 and gear 208 out of engagement with the film cassette gear 200. The gears 206, 208 pivot on the pivot plate 230. In this position, gear 206 is connected to the combined advance/rewind mechanism 12 and the film cassette gear 200 is driven to rotate by the combined advance/rewind mechanism 12, as best seen in Figure 8. Rotation of the film cassette gear 200 pulls film from the film path into the film cassette and around the spindle of the film cassette. In contrast to rotation in the counterclockwise or advance direction, rotation of the combined advance/rewind mechanism in the clockwise or rewind direction, causes gear 220 to exert a force on gear 222 due to the direction of rotation of gear 220 that urges gear 222 away from gear 224 to disconnect gear 222 from gear 224. Therefore, rotation of the combined advance/rewind mechanism in the rewind direction will drive rotation of the spindle of the film cassette, but not rotation of the film spool. FILM LOADING/REWINDING An improved method of manually loading film 14, without a motor, is illustrated in Figures 2-7. Preferably, this improved method of manually loading film 14 applies to APS film 14 or film 14 that can be thrust from a film cassette 16. A film cassette 16 may be inserted into the camera 10 and light sealed with in the camera 10, as described in commonly assigned United States Patent No. 5,689,733, entitled "Film Loading Method For A Single Use Camera," and United States Patent Application number 08/855,073, entitled "Single Use Camera With Battery Located In Film Spool" both of which are hereby incoφorated by reference. That is the film cassette 16 may be inserted through a door in the bottom of the camera 10, and a tab or other structure may them be placed over the bottom of the camera 10 to light seal the camera 10, including the film cassette 16, the film spool 22 and the film path, this process is described in more detail below. Although this patent and application disclose a single use camera 10, it will be appreciated that a hinged tab, or other structure that can seal the film cassette compartment, can be employed in a reusable camera 10. Such a door is shown in the KODAK ADVANTIX™ 1600 camera 10, which is a camera 10 that employs a motor to move the move film 14 from the film cassette 16 to the film spool 22. After the film cassette 16 is loaded into the camera 10, the light lock door of the film cassette 16 may be opened, similar to the way it is opened in the KODAK ADVANTIX™ 1600 camera. In that camera 10, the light lock door is interlocked with the tab over the film cassette compartment, so that when the tab is placed over the film cassette compartment, the light lock door of the film cassette 16 is opened. Other means may be employed to open the light lock door of the film cassette 16. In order to manually thrust the film 14 from the film cassette 16 and load the film, the advance wheel 30 may be rotated in the advance or counter clockwise direction, as shown in Figure 2. When rotated in the counterclockwise direction, the advance wheel 30 will rotate the drive gear 204 which is coupled to the advance wheel 30 in the clockwise direction. Gear 210 will be driven by the drive gear 204 to rotate in the clockwise direction, as will gear 212, since it is mounted on a common shaft with gear 210. Because gears 210 and 212 are rotating clockwise, gear 212 will push gear 208 into engagement with the film cassette gear 200 and drive gear 206 out of engagement with the film cassette gear 200. The film cassette gear 200 will be driven to rotate in the clockwise direction to thrust film 14 out of the film cassette 16, as shown in Figures 2 and 3. As gear 214 rotates, it drives the gear train 24 to rotate in the directions indicated in Figure 2. Gear 220 rotates in the counterclockwise direction and pushes gear 222 to engage gear 224 and couple the advance wheel 30 to the film spool gear 202. In this position, the rotation of the advance wheel 30 causes rotation of the film spool 22 in the counterclockwise direction so that it is moving in the direction to pull film 14 from the cassette 16. As shown in Figures 4 and 5, continued rotation of the advance wheel 30 will thrust the film 14 until an edge of the film 14, the leading edge of the film engages the film spool 22 and the film 14 is wrapped around the film spool 22. Because as described above, the film is wrapped relatively loosely around the film spool, and the linear thrust speed is greater than the linear pulling speed, the film is thrust as it initially wraps around the film spool. As the film is wrapped around the film spool 22, the film is captured between the film spool 22 and one or more pads 22a which aid in winding the film relatively tightly around the film spool 22. Wrapping the film around the film spool 22, links the film spool to the spindle of the film cassette. The film acts as a belt. Due to the gear train 24, the film spool 22 is rotated faster than the film cassette spindle when the film is wrapped sufficiently around the film spool 22 and the film becomes relatively taught. Because of this increased speed of rotation and the linking of the film spool with the film cassette gear by the film, the film cassette gear 200 exerts a force on gear 208 to cause gear 208 to swing out of engagement with the film cassette gear, as depicted in Figure 6 once a substantial amount of the slack has been removed from the film and the film is relatively taught. At this point, the combined advance/rewind mechanism is no longer coupled to the film cassette. Thus, continued rotation of the combined advance/rewind mechanism drives the film spool to pull film out of the film cassette and wrap the film around the film spool; the film is no longer thrust, as shown in Figures 6 and 7. As described above, depending on how taught the film is and the speed differential, the film movement may switch to thrusting as opposed to pulling. If the film becomes relatively slack due to how it is wrapped around the spindle inside of the cassette or forces exerted by the camera components of the film, gear 208 will swing back into engagement with the film cassette gear, so that the film is thrust rather than pulled as it is advanced. This occurs because as the film becomes relatively slack, the speed of rotation of the film spool decreases, and the gear 208 will swing back into engagement with the film cassette gear to drive the film. The film is advanced out of the film cassette until the leading edge of the film is wrapped around the film spool and the first frame is disposed within the film exposing area of the camera. At this point the first frame of film is ready to be exposed. After a picture is taken with the camera, the combined advance/rewind is rotated to advance the exposed frame to the film spool and to position the next frame in the film exposing area. Depending on how taught the film is, this operation is depicted in either Figures 6 and 7 or Figures 4 and 5. The film is advanced by the rotating the thumb wheel of the combined advance/rewind mechanism in the advance or counter clockwise direction. This causes the film spool to rotate to pull the film around the film spool 22 or the film spindle to rotate and thrust film depending on the tension on the film as described above. When film 14 is to be rewound into the film cassette 16 after all of the exposure have been taken, the advance wheel 30 is rotated in the clockwise direction, as shown in Figure 8. This is done by rotating the rewind crank to its second position, so that the advance wheel can be turned in the clockwise or rewind direction. As described above, if the rewind crank is not rotated to its second position, the advance wheel cannot be rotated in the rewind direction. As the advance wheel rotates in the clockwise direction, the drive gear 202 also rotates in the clockwise direction and drive gears 210 and 212 to rotate in the counterclockwise direction. This motion of gear 212 causes gear 208 to remain out of engagement with the film cassette gear 200 and gear 206 to move into engagement with the film cassette gear 200. Gear 206 is driven to rotate in the clockwise direction, and it in turn drives the film cassette gear 200 to rotate in the counterclockwise direction. This motion of the film cassette gear 200 drives the spindle 27 of the film cassette 16 to rewind or pull film 14 from the film spool 22 back into the film cassette 16. Gear 212 drives gears 214-220 to rotate, as shown in Figure 8. Since gear 220 is driven to rotate in the clockwise direction, gear 220 causes gear 222 to rotate on its pivotable plate out of engagement with gear 224. In this position, the advance wheel 30 is decoupled from the film spool 22, so that when film is being rewound into the film cassette 16, the film spool 22 is not driven to rotate by the advance wheel 30. The film spool 22 does, however, rotate due to the pulling of film 14 to the film cassette 16, as shown in Figure 9. The advance wheel 30 used with this gear train 24 may be the combined advance/rewind mechanism 12 described above. REWIND INTERLOCK As alluded to above, the camera of this invention may further include a rewind interlock that prevents a camera user from creating a double exposure or exposing the same frame of film twice and thereby destroying a picture. In the embodiment shown primarily in Figures 16-24, the rewind interlock prevents moving exposed film from the film path to the film spool after the exposed film has been rewound into the film cassette. Because of this interlock, exposed film, that has been rewound into the film cassette, cannot be advanced back into the film path. For instance, an exposed frame of film cannot be moved from the film cassette back into the film path by the accidental manipulation of the combined advance/rewind mechanism. This interlock may be used in combination with either embodiment of the combined advance/rewind mechanisms described above. Similarly, this interlock may be practiced with other film advance and film rewind mechanisms including the two embodiments described above. The rewind interlock of this invention may be practiced with a variety of film advancing mechanisms. According to a prefeπed embodiment, the rewind interlock 300 includes a plate 302, a pawl 304, a spring 306, an interlock lever 308, the door 320 of the film cassette compartment, a stop 321, a door lever 322, an actuator 324, a segmented gear 326, a linkage 328 and a spring 330 as shown in Figures 16-24. Figures 16 and 17 are assembly drawings illustrating the assembly of the pawl 304 and the interlock lever 308 to the camera, and Figures 17A-17H depict features of the rewind interlock. Figures 18, 19, 20, 21, 22, 23 and 24 are top views and Figures 20A, 21 A, 22A and 23 A are bottom views depicting the operation of the rewind interlock. The interlock lever 308 may be rotatably mounted to the camera with a rivet 310 or any of a variety of fasteners, as best seen in Figures 16 and 17. Extending from one end of the interlock lever 308 may be a post 312. The post 312 may be integrally formed with the lever 308, as shown, or attached in a variety of manners. Connected to the post 312 may be the pawl 304. Preferably, the pawl 304 is rotatably mounted to the post 312 . Thus, the pawl 304 is rotatable about two different axes; the pawl 304 rotates about the post 312 relative to the interlock lever 308 and rotates with the interlock lever 308, as the interlock lever rotates about the rivet 310. As is best shown in Figure 17, extending downward from the pawl 304 may be a stem 314. The stem 314 may be integrally formed with the pawl 304 or fastened to the pawl 304 in any of a variety of ways. The spring 306, shown in Figure 18, may be coupled to the stem 314 and the main body of the camera. The spring 306 biases the pawl 304 to rotate in the counter clockwise direction as viewed in Figure 18. Since the interlock lever 308 is coupled to the spring 306 by the pawl 304, the spring 306 also biases the interlock lever 308 to rotate, but in the clockwise direction. As shown in Figure 17, the combined advance/rewind mechanism may have a notch 316 extending form an inner surface 318. The notch 316 interacts with the pawl 304 to prevent rotation of the combined film advance/rewind mechanism after film has been rewound. In particular, the notch 316 interacts with the angled end 319 of the pawl 304. The plate 302, shown in Figures 17A, 17C and 17E, is preferably slidably mounted to the camera, so that it can interact with the interlock lever 308. Extending from the plate 302 may be a tab 318 for interfacing with the interlock lever 308, as shown in Figure 20. The plate 302 may further have a retainer 302a, as shown in Figures 17 A, 17B and 17D for interfacing with the linkage 328. As is also shown in Figure 17A, the plate 302 has a hooked end 332 that connects to the spring 330. The linkage 328 is preferably rotatably mounted to the camera by a stem 334. Coupled to the stem 334 is the spring 330. The linkage 328 preferably has a member 328a extending laterally from the linkage for interfacing with the plate 302 and a tab 336 for interfacing with a film cassette 16, as described below. The tab 336 extends into the film cassette compartment through a slot 338 in the camera body. A stop 340 may be mounted to the camera to prevent rotation of the interlock lever 308 in the counter clockwise direction. The stop 340 may be defined by a large body of the camera as shown in Figures 17 and 20A. Alternatively, the stop may be a separate piece, such as a plate or the like, that is attached to a large part of the camera structure. As explained below, by limiting rotation of the interlock lever, the stop 340 maintains the interlock lever 308 in place during the advancement of film. As alluded to above, the camera may further have an actuator 324, a door lever 322, a segmented gear 326, the door 339 of the film cassette compartment and a light lock door driver 341. The door lever 322 is coupled to the actuator 324 and the actuator 324 is coupled to the side of the camera, as shown diagrammatically in Figures 17A and 17F- 17H. The light lock door driver 341, as shown in Figures 17C and 17E, is preferably rotatably mounted to the camera and positioned so that it is engageable with the light lock door of the film cassette 16 when the film cassette 16 is inserted into the film cassette compartment. Rotation of the light lock door driver 341, rotates the light lock door and thereby open and close the light lock door. Such drivers are known in the art. For example, a similar driver is disclosed in commonly assigned U.S. Patent No. 5,689,733, issued on November 18, 1997, which is hereby incoφorated by reference. The segmented gear 326 is preferably rotatably mounted to the camera above the film cassette compartment, as shown in Figures 17A, 17C and 17E. The geared portion of the segmented gear 326 is engageable with the light lock door driver 341, so that the segmented gear 326 can drive the light lock door driver 341 to move the light lock door between the open and closed positions. The segmented gear 326 is not however, coupled to the combined advance/rewind mechanism, so the segmented gear 326 does not move in response to movement of the combined advance/rewind mechanism. Extending from the periphery of the segmented gear 326 is a finger 327, as shown in Figures 17A, 17C and 17E, for engaging the actuator 324. An end of the finger 327 is preferably spherical shaped. As shown in Figures 17A and 17F, the actuator 324 is rotatably mounted to the side of the camera and includes a forked end 343. The finger 327 is disposed in the forked end 343 with the spherical end holding the finger 327 within the forked end 343, so that the segmented gear 326 is coupled to the actuator 324. A variety of other fastening techniques may be used to couple the segmented gear 326 to the actuator 324. Preferably, the segmented gear 326 rotates with the movement of the actuator 324. At the bottom of the camera is the hinged door 339 that covers the film cassette compartment, as shown in Figures 17A and Figures 17F-17H. Extending from the hinged door 339 may be a tab 345 that engages the actuator 324 to rotate the actuator 324, the segmented gear 326, the light lock door driver 341 and the light lock door, as the hinged door 339 is closed, as shown in Figures 17F and 17H, and as explained in detail below. Neither the hinged door 339 nor the actuator 324 themselves are new. For example, they may be found in the Kodak™ ADVANTIX™ Camera manufactured by the assignee of this invention. After a film cassette 16 is inserted into the camera, the hinged door 339 is moved to the closed position, as shown in Figure 17H. When the hinged door 339 moves to the closed position, the hinged door 339 engages the actuator 324 to drive the actuator 324 to rotate. As the actuator 324 rotates, the segmented gear 326 rotates. The segmented gear 326 drives the light lock door driver 341 to rotate the light lock door of the film cassette 16 to the open position. The end of the actuator 324 opposite that of the forked end 343 preferably has a first arm 350 and a second arm 352, as shown in Figures 17A and 17F-17H. The first arm 350 is preferably biased by a spring 354 that is coupled to the body of the actuator 324 and the first arm 350. The spring 354 preferably biases the first arm 350 to rotate clockwise away from the body of the actuator 324. As is shown in Figure 17F, the second arm 352 cooperates with the tab extending from the hinged door 339 to hold the hinged door 339 in the closed position. A door spring 356 is preferably coupled to the camera body and the actuator 324 to bias the actuator 324 to rotate in the clockwise direction, as shown for example in Figures 17F-17H. A notch 358 is preferably disposed on the camera, as is also shown in Figures 17F-17H . The notch 358 holds the first arm 350 when the actuator 324 is rotated against the bias of the door spring 356 to hold the actuator 324 against the bias of the door spring 356. A door lever 322, as shown in Figures 17A, may be disposed on a side of the camera and coupled to the actuator 324. The camera user can push the door lever 322 to rotate the actuator 324 and thereby open the hinged door 339 and shut the light lock door of the film cassette 16. The door lever 322 is interlocked with the hinged door 339 and the light lock door driver 341 to prevent a camera user from opening the hinged door 339 when film extends from the light lock door and thereby prevents unwanted exposure of film. Further operation of the actuator 324, the hinged door 339 and the light lock door driver 341 are described below. OPERATION OF THE REWIND INTERLOCK Operation of the rewind interlock is best understood with reference to Figures 18- 24. Figures 18, 19, 20, 21, 22, 23 and 24 are top views and Figures 20A, 21 A, 22A and 23 A are bottom views depicting the operation of the components of the rewind interlock 300. Figures 17D and 17E are top views taken at a lower elevation then those of Figures 18 and 19-24 and depict the operation of the linkage and plate 302. Figures 17F-17H depict the closing and opening of the hinged door 339 of the film cassette compartment. Operation of the rewind interlock is also best understood beginning with the insertion of a film cassette 16 into the film cassette compartment. Prior to inserting a film cassette 16 into the film cassette compartment, the hinged door 339, the segmented gear 326, the actuator 324 and the door lever 322 are in the positions shown in Figure 17G. Further, Figures 17B and 17C depicts the linkage 328, as a film cassette 16 is being withdrawn from or inserted into the camera, and alternatively the position of the segmented gear 326 and the plate 302 when the film cassette 16 is being withdrawn from or inserted into the camera and the door 339 is open. Figure 17D illustrates the linkage 328 after the film cassette 16 has been fully inserted. Figure 17E illustrates the position of the plate 302 and the segmented gear 326 after the insertion of a film cassette 16 and after closing of the door 339 of the film cassette compartment. The film loading process begins with inserting a film cassette into the film cassette compartment, as shown in Figure 17B. It will be appreciated from Figures 17 A, 18B and 17D that the film cassette 16 contacts the tab 336 upon insertion into the film cassette compartment. Further insertion of the film cassette 16 pushes the tab 336 and causes the linkage 328 to rotate clockwise, as viewed in Figure 17B, about the stem 334. As the linkage 328 rotates, the spring 330 is compressed because one end of the spring 330 is coupled to the plate 302 and the other end is coupled to the linkage 328, as best understood with reference to Figures 17A, 17C and 17D. As the spring 330 is compressed, the spring 330 exerts a force on the plate 302 that urges the plate 302 to move to the right, as best understood with reference to Figures 17B and 17E. Further insertion of the film cassette, rotates the linkage 328 to the position shown in Figure 17D. At this point in the film loading process, the film cassette is inserted and the door 339 is still open. Since the door 339 is still open, the segmented gear 326 is in the position shown in Figure 17C after insertion of the film cassette 16. In this position, the plate 302 is urged to move to the right, as shown in Figure 17E, and the plate, urged by the spring 330, pushes on the segmented gear 326 which is in the position of Figure 17C, but the segmented gear 326 cannot rotate because the force exerted by the plate 302 is not sufficient to overcome the force needed to rotate the segmented gear 326 and the actuator 324, which is prevented from rotating by the notch 345 shown in Figure 17F, coupled to the segmented gear 326. The plate 302 cannot move to the right until the segmented gear 326 is rotated due to the closing of the hinged door 339, as described below. As the film cassette 16 is inserted into the camera, the light lock door becomes coupled to the light lock door driver 341. In order to light seal the film cassette 16 within the film cassette compartment, the hinged door 339 is moved, as shown in Figure 17H, from the open position of Figure 17G to the closed position of Figure 17F. As the hinged door 339 is closed, the tab 345 of the hinged door 339 engages the actuator 324 to cause the actuator 324 to push the first arm 350 of the actuator 324 against the bias of the spring 356, as shown in Figure 17H. Once the tab pushes the first arm 350 above the notch 358, the actuator 324 rotates clockwise due to the door spring 356 to the position shown in Figure 17F. As the actuator 324 rotates, the second arm 352 engages the tab and rests underneath the tab 345 to prevent opening of the hinged door 339 unless the actuator 324 is rotated. Further, once the actuator 324 rotates, the first arm 350 is pushed by the spring 354 to rest against the notch 358, as shown in Figure 17F. Because the segmented gear 326 is coupled to the actuator 324, rotation of the actuator 324 upon the closing of the hinged door 339 rotates the segmented gear 326 in the counter clockwise direction, as shown in Figure 17E, and as is also illustrated by comparing Figures 17H and 17F. This rotation of the segmented gear 326 releases the plate 302, so that the plate 302, due to the urging of the spring 330, moves to the right, as shown in Figure 17E. Rotation of the segmented gear 326 upon closing the hinged door 339 also rotates the light lock door driver 341 to open the light lock door of the film cassette 16, which is best understood by comparing Figures 17C and 17E. As the film cassette 16 is being inserted and the linkage 328 is rotating, the member 328a is positioned to the right side of the retainer 302a defined by the plate 302, as shown in Figure 17B. When the plate 302 moves to the right, as described above when the door 339 is closed, the left side of the retainer 302a captures the member 328a to hold the member 328a and the linkage 328, as shown in Figure 17D. Movement of the plate 302 to the right, also releases the interlock lever 308 to rotate in the counter clockwise direction due to the biasing of the spring 306. As shown in Figure 18, in this position the end of the pawl 304 rests against the inner periphery of the combined advance/rewind mechanism and the interlock lever rests against the tab 318. With the components in the position illustrated in Figure 18, which may be refeπed to as the first position, the combined advance/rewind mechanism may be rotated continuously or intermittently in the counter clockwise or advance direction to advance the film from the film cassette to the film exposing area, and the film from the film exposing area to the film spool. This is best illustrated with reference to Figure 19. As shown, when the combined advance/rewind mechanism is rotated the notch 316 will contact the end of the pawl 304. Upon contacting the end of the pawl 304, the notch 316 pushes the pawl 304 to rotate the pawl 304 counter clockwise against the bias of the spring 306 until the notch 316 passes by the pawl 304. The interlock lever 308 does not rotate because it is prevented from rotation by the stop 340, as best understood with reference to Figures 17 and 20 A. Continuation rotation of the advance/rewind mechanism moves the notch 316 past the pawl 304 and the pawl 304 is released. When released the spring 306 biases the pawl 304 to rotate clockwise so that it again rests against the inner periphery of the combined advance/rewind mechanism, as shown in Figures 20 and 20 A. The stop 340 shown in Figures 17 and 20A prevents any significant degree of rotation of the interlock lever 308 in the clockwise direction, as the pawl 304 is being rotated counter clockwise, as viewed in Figures 18 and 19. Therefore, the interlock lever 308 remains relatively stationary as the film is advanced. This is best understood with reference to Figure 20A, which is a bottom view showing the interlock lever 308 resting against the stop 340. Thus, with the pawl 304 and the rewind interlock 308 in their first position, the combined advance/rewind mechanism is free to rotate in the advance direction, so that the leading edge of the film can be advanced to the film spool and the film can be advanced to the film spool after each frame of film is successively exposed in the film exposing area. Typically, after all of the exposures have been taken, the film is rewound into the film cassette 16. The rewind interlock prevents attempting to advance the film after the film has been rewound into the cassette. This prevents exposed film from being exposed again. Similarly, if exposed film is rewound before all of the film has been exposed, the rewind interlock will prevent advancing the film and the creation of a double exposure. This prevents the accidental loss of an exposure. Moreover, if the camera is of the type where the film is loaded onto the film spool prior to exposing the film and each exposed frame is moved into the film cassette after it has been exposed, the rewind interlock prevents moving the exposed film out of the film cassette and into the film exposing area The rewind interlock does this as shown in Figures 20-23. As shown in Figures 20 and 21, the combined advance/rewind mechanism is rotated in the clockwise direction in order to rewind the film. Eventually, the notch 316 engages the angled end 319 of the pawl 304, as shown in Figures 20 and 20A. Continued rotation of the combined advance/rewind mechanism pushes the pawl 304 to rotate clockwise about the stem and the interlock lever 308 to rotate clockwise about the rivet against the bias of the spring 306, as shown in Figures 21 and 21 A. The pawl 304 rotates with the interlock lever 308 and rides along the stop, as shown in Figure 21. The interlock lever 308 rotates away from the stop 340. As the combined advance rewind mechanism is being rotated, film is being moved from the film exposing area and the film spool back to the film cassette. As shown in Figures 22 and 23, continued rotation of the combined advance/rewind mechanism moves the notch 316 past the pawl 304 and releases the pawl 304 and the interlock lever 308. The spring 306 biases the pawl 304 to rotate against the inner periphery of the combined advance/rewind mechanism, and the interlock lever 308 to rotate counterclockwise as shown in Figures 22 and 22 A. The interlock lever 308 rotates clockwise, as viewed in Figure 22A, until the interlock lever 308 contacts the stop 340. In this position or second position, the pawl 304 is disposed so that the angled end 319 of the pawl 304 is in a different position relative to the notch 316. In the first position, the angled end 319 was not contacted by the combined advance/rewind mechanism when this mechanism was rotated in the clockwise or advance direction, as shown in Figure 19. However, when the pawl 304 is in the second position, the angled end 319 will be contacted by the notch 316, as the combined advance/rewind mechanism rotates in the advance direction. After the notch 316 releases the pawl 304, the rewind interlock is established. This is best understood with reference to Figures 23 and 23 A. If an attempt is made to advance the film after the interlock is set, the notch 316 will engage the angled end 319 of the pawl 304 to try to rotate the pawl 304 and the interlock lever 308 in the counter clockwise direction, as viewed in Figure 23 (counterclockwise as viewed in Figure 23 A). In this position, the interlock lever 308 will rest against the stop 340 shown in Figure 23 A. Due to an angled portion of the notch 316 engaging a coπesponding angled end 319 of the pawl 304, as shown in Figures 23 and 23 A, rotation of the both the pawl 304 and the interlock lever 308. Thus, the film cannot be advanced after it has been rewound. As alluded to above, the rewind interlock of this invention may be employed with a variety of film advancing or rewinding mechanisms and is not limited to the combined advancing/rewind mechanism. Rather, the rewind interlock can be practiced with a wheel that has a notch disposed along its inner periphery and that rotates as film is moved within the camera. It will be appreciated that the combined advance/rewind mechanism may be rotated to a certain extent in the rewind direction before the interlock is set. This depends on the location of the notch relative to the pawl before the rewind motion is initiated. In order to prevent rewinding of the film, the gear train can be designed so that there is enough slack in it to prevent the film from being rewound to any significant degree before the interlock is set. Alternatively, a plurality of notches may be disposed along the inner periphery of the combined advance/rewind mechanism. In order to reset the rewind interlock so that film can be advanced from a film cassette, the film cassette 16 is removed from the camera. This occurs as follows. The door lever 322 of Figure 17A is rotated by a camera user to open the hinged door 339 as follows. Since the actuator 324 is coupled to the door lever 322, the actuator 324 rotates with the door lever 322. As shown by comparing Figures 17F and 17G, the rotation of the actuator 324 counter clockwise against the bias of the door spring 356, causes the first arm 350 to slide along the notch 358 and the second arm 352 to move away from the tab of the hinged door 339. Eventually, the second arm 352 becomes disengaged from the tab, and the hinged door 339 is free to open. Further, the first arm 352 also rotates past the notch 358 and the spring 354 biases the first arm 352 to move to engage the notch 358, as shown in Figure 17G. With the hinged door 339 opened, the film cassette can be removed. Because the segmented gear 326 is coupled to the actuator 324, the segmented gear 326 rotates, as shown in Figures 17F and 17G, as the actuator 324 rotates with the door lever 322. This is also shown in Figure 17C, which depicts the segmented gear 326 rotating in the clockwise direction, as the door 339 is being opened. Opening of the door 339 permits withdraw of the film cassette 16 from the film cassette compartment. As the segmented gear 326 rotates in the clockwise direction, the segmented gear 326 engages the plate 302 and pushes the plate 302 to the left against the bias of the spring 330 as shown in Figure 17C. Upon moving to the left, the tab 318 of the plate 302 engages the interlock lever 308 to rotate the interlock lever 308 in the clockwise direction as shown in Figure 24. As the interlock lever 308 rotates clockwise, the pawl 304 rotates with the interlock lever 308 and no longer rests against the inner periphery of the combined rewind/advance mechanism. This releases the pawl 304. Once released, the spring 306 causes the pawl 304 to rotate clockwise relative to the interlock lever 308, as best understood by comparing Figures 23 and 24. The pawl 304 and the interlock lever 308 have been reset because the pawl 304 has rotated relative to the notch 316, so that the angled end 319 of the pawl 304 will not engage the notch 316 as the advance/rewind mechanism is rotated in the advance direction to prevent rotation of the advance/rewind mechanism. Figure 17B illustrates the plate 302 and the linkage 328, as the film cassette 16 is being removed from the film cassette compartment. As described above, opening of the door 339 causes the plate 302 to slide to the left, as shown in Figures 17C and 24, against the bias of the spring 330. As the plate 302 moves to the left, the member 328a of the linkage 328 is release from the retainer 302a of the plate 302, as is best understood with reference to Figure 17B. Once released, the spring 330 causes the linkage 328 to rotate counter clockwise, as shown in Figure 17B. In this position, the camera is ready for insertion of another film cassette. If desired a film cassette can be inserted into the film cassette compartment and the hinged door 339 can be closed. Closing of the hinged door moves the pawl 304 and the interlock lever 308 back to the position of Figure 18. This occurs because the closing of the hinged door moves the slide 302 to the right, which releases the interlock lever 308. Once released the interlock lever 308 rotates counter clockwise from the position of Figure 24 to the position of Figure 18. The pawl 304 rotates with the interlock lever 308, so that the pawl 304 rests against the inner periphery again. Now, the pawl 304 and the interlock lever 308 are back in their first position. That is the pawl 304 has rotated relative to the notch 316, so that the angled end of the pawl 304 will not engage the pawl 304 as the advance/rewind mechanism is rotated in the advance direction. It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and aπangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims: What is claimed is: 1. A camera of the type that has a film cassette compartment for receiving a film cassette, a film spool around which film can be wound and a film exposing area disposed between the film cassette compartment and the film spool, comprising: a wheel that is rotatably mounted to the camera above the film cassette compartment and that is coupled to the film cassette when the film cassette is loaded into the film cassette compartment, the wheel being rotatably mounted so that when the wheel is rotated in an advance direction, the film is advanced from the film cassette across the film exposing area and around the film spool and when the wheel is rotated in a rewind direction, the film is rewound from the film spool across the film exposing area and into the film cassette compartment, the wheel comprising an inner periphery that has a notch that rotates with the wheel; and a rewind interlock, mounted to the camera and disposed within a cavity defined by inner periphery of the wheel, the notch engaging the rewind interlock when the wheel is rotated in the rewind direction to move the rewind interlock to a position that prevents rotating the wheel in the advance direction to thereby prevent exposed rewound film from being exposed twice. 2. The camera of claim 1, wherein the wheel comprises an integrally formed combined advance and rewind mechanism. 3. The camera of claim 1, wherein the rewind interlock comprises a rotatable pawl and wherein the notch engages the pawl when the wheel is rotated in the rewind direction to move the pawl to a position in which the pawl prevents rotation of the wheel in the advance direction. 4. The camera of claim 3, wherein the rewind interlock further comprises a spring that is coupled to the pawl to bias the pawl to a reset position in which the pawl is not engaged with the notch and the wheel can be rotated in the advance direction. 5. The camera of claim 4, wherein the rewind interlock further comprises an interlock lever that is rotatably mounted to the camera and wherein the pawl is rotatably mounted to the rewind interlock, the rewind interlock being rotatable to move the pawl to the reset position, so that the wheel can be rotated in the advance direction to move film from the film cassette compartment to the film spool after the film cassette has been removed from the camera. 6. The camera of claim 1 , wherein the rewind interlock comprises a rotatable pawl that is mounted to a rotatable interlock lever, the pawl being rotatable about a stem of the interlock lever and the interlock lever being rotatable about a pivot pin mounted to the camera, the pawl moving with the interlock lever as the interlock lever rotates about the pivot pin. 7. The camera of claim 6, wherein the rewind interlock and the pawl each having a first position in which the pawl rests against the inner periphery of the wheel and the notch in the wheel can be rotated past the pawl as the wheel is rotated in the advance direction and a second position in which the notch engages the pawl when the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl and thereby prevent advancing the film, the wheel moving the interlock lever and the pawl to the second position when the wheel is rotated in the rewind direction and the notch engages the pawl to push the pawl and cause the pawl to rotate about the stem and the interlock lever to rotate about the pivot point to move from the first position to the second position. 8. The camera of claim 7, wherein the pawl comprises an angled end that engages the notch when the pawl is in the second position and the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl when the wheel is rotated in the advance direction. 9. A camera of the type that has a film cassette compartment for receiving a film cassette, a film spool around which film can be wound and a film exposing area disposed between the film cassette compartment and the film spool, comprising: a wheel that is rotatably mounted to the camera above the film cassette compartment and that is coupled to the film cassette when the film cassette is loaded into the film cassette compartment, the wheel being rotatably mounted so that when the wheel is rotated in an advance direction, the film is advanced from the film cassette across the film exposing area and around the film spool and when the wheel is rotated in a rewind direction, the film is rewound from the film spool across the film exposing area and into the film cassette compartment, the wheel comprising an inner periphery that has a notch that rotates with the wheel; and a pawl, moveably mounted to the camera and disposed inside of the wheel, the pawl having a first position in which the notch contacts the pawl during each revolution of the wheel when the wheel is rotated in the advance direction and permits film to be advanced from the film cassette across the film exposing area and to the film spool, and a second position which the pawl moves to in response to rotation of the wheel in the rewind direction, the pawl preventing rotation of the notch on the wheel past the pawl when the wheel is rotated in the advance direction when the pawl is in the second position, and thereby preventing exposed rewound film from being advanced and exposed twice. 10. The camera of claim 9, further comprising a spring that is coupled to the pawl to bias the pawl to a reset position in which the pawl is not engaged with the notch and the wheel can be rotated in the advance direction. 11. The camera of claim 9, further comprising an interlock lever that is rotatably mounted to the camera and wherein the pawl is rotatably mounted to the rewind interlock, the rewind interlock being rotatable to move the pawl to the reset position, so that the wheel can be rotated in the advance direction to move film from the film cassette compartment to the film spool after the film cassette has been removed from the camera. 12. The camera of claim 9, wherein the rotatable pawl is mounted to a rotatable interlock lever, the pawl being rotatable about a stem of the interlock lever and the interlock lever being rotatable about a pivot pin, the pawl moving with the interlock lever as the interlock lever rotates about the pivot pin. 13. The camera of claim 12, wherein the rewind interlock and the pawl have a first position in which the pawl rests against the inner periphery of the wheel and the notch in the wheel can be rotated past the pawl as the wheel is rotated in the advance direction and a second position in which the pawl engages the notch of the wheel when the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl and thereby prevent advancing the film, the wheel moving the interlock lever and the pawl to the second position when the wheel is rotated in the rewind direction by engaging the pawl to push the pawl and cause the pawl to rotate about the stem and the interlock lever to rotate about the pivot point. 14. The camera of claim 12, wherein the pawl comprises an angled end that engages the notch when the pawl is in the second position and the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl when the wheel is rotated in the advance direction. 15. A camera that prevents double exposure of the film, comprising: a film cassette compartment mounted on a first end of the camera into which a film cassette can be inserted; a film spool disposed on a second end of the camera; a film exposing area, disposed between the film cassette compartment and the film spool, in which film is exposed; a wheel rotatably mounted to the camera above the film cassette compartment and being coupled to the film cassette when the film cassette is inserted into the film cassette compartment, the wheel having a notch disposed on an inner periphery, the wheel being rotatable in an advance direction to advance unexposed film from the film cassette to the film exposing area to be exposed and rotatable in a rewind direction to rewind exposed film from the film exposing area to the film cassette; a pawl, moveably mounted to the camera inside of the wheel and being disposed so that the notch contacts the pawl as the wheel rotates, the notch engaging the pawl, when the wheel is rotated in the rewind direction to move the pawl to a position in which the notch engages the pawl to prevent rotation of the notch past the pawl when the wheel is rotated in the advance direction to thereby prevent exposed rewound film from being advanced from the film cassette compartment to the film exposing area and exposed twice. 16. The camera of claim 15, further comprising an interlock lever that is rotatably mounted to the camera and to which the pawl is mounted, the interlock lever being rotatable to reset the pawl, so that the wheel can be rotated in the advance direction. 17. The camera of claim 15, wherein the wheel comprises an integrally formed combined advance and rewind mechanism. 18. The camera of claim 15, wherein the rotatable pawl is mounted to a rotatable interlock lever, the pawl being rotatable about a stem of the interlock lever and the interlock lever being rotatable about a pivot pin, the pawl moving with the interlock lever as the interlock lever rotates about the pivot pin. 19. The camera of claim 18, wherein the rewind interlock and the pawl have a first position in which the pawl rests against the inner periphery of the wheel and the notch in the wheel can be rotated past the pawl as the wheel is rotated in the advance direction and a second position in which the notch engages the pawl of the wheel when the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl and thereby prevent advancing the film, the wheel moving the interlock lever and the pawl to the second position when the wheel is rotated in the rewind direction and the notch engages the pawl to push the pawl and cause the pawl to rotate about the stem and the interlock lever to rotate about the pivot point. 20. The camera of claim 19, wherein the pawl comprises an angled end that engages the notch when the pawl is in the second position and the wheel is rotated in the advance direction to prevent rotation of the notch past the pawl when the wheel is rotated in the advance direction.

Inventors: BITTNER WILFRIED, BITTNER, WILFRIED
Applicants: CONCORD CAMERA CORP, CONCORD CAMERA CORP.
Application year: 2000
Main classification: G03B1
IPC codes: G03B1, G03B17, G03C3