Abstract:
A film cartridge comprises a housing having a film exit slit, and a film roll support rotatable inside the housing to unwind a filmstrip beginning with a film leader having several frame lengths from the film roll support to permit the film leader to be moved outwardly through the slit to accomplish film loading in a camera. A visible film-loaded indicator is located on the exterior of the housing to be seen through a window in a camera. A flexible cover strip has an opaque portion covering the film-loaded indicator to prevent the indicator from being seen and a film engaging portion located at the slit. Engageable means is located on the film leader for engagement with the film engaging portion as the film leader is moved outwardly through the slit, to make the opaque portion be drawn off the film-loaded indicator to uncover the indicator when the film leader is moved out of the housing sufficiently to accomplish film loading in a camera.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Reference is made to commonly assigned copending applications Ser. No. 08/584480 entitled FILM CARTRIDGE WITH VISUAL INDICATOR FOR VERIFYING FILM LOADING IN CAMERA and filed Jan. 11, 1996 in the names of Joseph A. Manico and Dwight J. Petruchik, and Ser. No. 08/449032, entitled FILM SPOOL WITH BUILT-IN AUDIBLE INDICATOR FOR VERIFYING FILM LOADING IN CAMERA and filed May 24, 1995 in the name of Joseph A. Manico. 
     FIELD OF THE INVENTION 
     The invention relates generally to the field of photography, and in particular to a film cartridge with a visual indicator for verifying film loading in a camera for example. 
     BACKGROUND OF THE INVENTION 
     To load most 35 mm cameras, a film cartridge is inserted in a loading chamber of the camera and the forward end portion of a film leader protruding from a light-trapping slit in the cartridge is placed over a take-up spool in the camera. In some cameras, the forward end portion of the film leader is manually attached to the take-up spool before a rear door of the camera is closed. Then, a film loading or winding operation is performed, for example, by manually pivoting a winding lever for the take-up spool and manually depressing a shutter release button several times. This is done until the entire leader is unwound from a supply spool inside the cartridge and is wound onto the take-up spool, and the first-available film frame is positioned for exposure. In other cameras, the forward end portion of the film leader is automatically secured to the take-up spool at the beginning of the film loading operation. As the take-up spool is rotated via a motor drive, for example, one or more circumferential teeth of the spool engage the forward end portion of the film leader at its perforations to wind the leader onto the spool and position the first-available film frame for exposure. A spring-like deflector or other suitable means may be provided on the rear door of the camera for pressing the film leader against the take-up spool to facilitate engagement of the forward end portion of the leader by the circumferential teeth of the spool. 
     A problem that exists in some 35 mm cameras is that even though the photographer believes the forward end portion of the film leader is secured to the take-up spool, the forward end portion may fail to be engaged with the spool or may become disengaged from the spool during the film loading operation. As a result, the film leader will not be wound onto the take-up spool and the first-available film frame cannot be positioned for exposure. However, since the rear door of the camera is closed, the photographer may not be aware of the malfunction. 
     SUMMARY OF THE INVENTION 
     A film cartridge comprising a housing having a film exit slit, and a film roll support rotatable inside the housing to unwind a filmstrip beginning with a film leader having several frame lengths from the film roll support to permit the film leader to be moved outwardly through the slit to accomplish film loading in a camera, is characterized by: 
     a visible film-loaded indicator located on the exterior of the housing to be seen through a window in a camera; 
     a flexible cover strip having an opaque portion covering the film-loaded indicator to prevent the indicator from being seen and a film engaging portion located at the slit; and 
     engageable means located on the film leader for engagement with the film engaging portion as the film leader is moved outwardly through the slit, to make the opaque portion be drawn off the film-loaded indicator to uncover the indicator when the film leader is moved out of the housing sufficiently to accomplish film loading in a camera. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial section view of a film cartridge with a visual indicator for verifying film loading in a camera according to a preferred embodiment of the invention, showing the cartridge with a film leader partially protruding from the cartridge before film loading; 
     FIG. 2 is a partial section view similar to FIG. 1, showing the cartridge with the film leader withdrawn from the cartridge for film loading; 
     FIG. 3 is a plan view of the cartridge as seen in FIG. 1; 
     FIG. 4 is a is a plan view of the cartridge as seen in FIG. 2; 
     FIG. 5 is a plan view of the cartridge, showing the film leader withdrawn farther than in FIG. 2; 
     FIG. 6 is a perspective view of the cartridge as seen in FIGS. 1 and 3; 
     FIG. 7 is a perspective view of the cartridge as seen in FIG. 5; 
     FIG. 8 is a rear elevation view of camera containing the cartridge as seen in FIGS. 1, 3 and 6; 
     FIG. 9 is a rear elevation view of camera containing the cartridge as seen in FIGS. 2, 4, 5 and 7; 
     FIG. 10 is a partial section view of a film cartridge with a visual indicator for verifying film loading in a camera according to a first alternate embodiment of the invention, showing the cartridge with a film leader partially protruding from the cartridge before film loading; 
     FIG. 11 is a partial section view similar to FIG. 10, showing the cartridge with the film leader withdrawn from the cartridge for film loading; 
     FIG. 12 is a partial section view similar to FIG. 10, showing the cartridge with the film leader withdrawn from the cartridge farther than in FIG. 11; 
     FIG. 13 is a partial section view similar to FIG. 12, showing a variation in design; 
     FIG. 14 is a partial section view of a film cartridge with a visual indicator for verifying film loading in a camera according to a second alternate embodiment of the invention, showing the cartridge with a film leader partially protruding from the cartridge before film loading; and 
     FIG. 15 is a partial section view similar to FIG. 14, showing the cartridge with the film leader withdrawn from the cartridge for film loading. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is disclosed as being embodied preferably in a film cartridge. Because the features of a film cartridge are generally known, the description which follows is directed in particular only to those elements forming part of or cooperating directly with the disclosed embodiment. It is to be understood, however, that other elements may take various forms known to a person of ordinary skill in the art. 
     Preferred Embodiment 
     Referring now to the drawings, FIGS. 1-7 show a film cartridge 10 comprising a housing 12 with a plush-lined light-trapping film exit slit 14 and a flanged film spool 16 rotatably supported inside the housing. A 35 mm filmstrip 18 having two identical series of edge perforations 20 inwardly adjacent respective longitudinal film edges 22 is loosely coiled in a film roll 24 about the film spool 16 between a pair of radial flanges, not shown, on the film spool. An inner end portion 26 of the filmstrip 18 is attached to the film spool 16. The first several frame lengths, i.e. 3-4 frame lengths, of the filmstrip 18 constitute a film leader 28. The film leader 28 forms an outermost convolution of the film roll 26 and has a partly reduced-width forward end portion 30 that initially protrudes from the film exit slit 14. See FIGS. 1, 3 and 6. 
     A &#34;FILM LOADED&#34; 32 indicator is imprinted on the exterior of the housing 12 at a location that permits the indicator to be seen through a rear window 34 of a camera 36 when the cartridge 10 is in the camera. See FIGS. 2, 4, 5, 7 and 9. A &#34;FILM USED&#34; indicator 38 is imprinted on the exterior of the housing 12 at a location that prevents the indicator from being seen through the rear window 34. 
     A flexible opaque cover strip 40 consists of a leading end portion 42 and a remaining trailing portion 44. The cover strip 40 is sufficiently narrower than the filmstrip 18 to be able to rest on the filmstrip between the two series of edge perforations 20 as shown in FIGS. 4, 5 and 7. The leading end portion 42 has an end hook 46 that is curved slightly into the film exit slit 14 as shown in FIG. 1, to rest on the protruding forward end portion 30 of the film leader 28. The remaining trailing portion 44 covers the &#34;FILM LOADED&#34; indicator 32 and the &#34;FILM USED&#34; indicator 38 as shown in FIGS. 1, 3 and 6. 
     A transparent open pocket 48 is secured to the exterior of the housing 12 to hold the remaining trailing portion 44 of the cover strip 40 in place over the &#34;FILM LOADED&#34; indicator 32 and the &#34;FILM USED&#34; indicator 38. 
     Operation 
     When the cartridge 10 is inserted in the camera 36, the &#34;FILM LOADED&#34; indicator 32 cannot be seen in the rear window 34 because the trailing portion 44 of the cover strip 40 is covering the indicator. See FIGS. 1, 3, 6 and 8. 
     The protruding forward end portion 30 of the film leader 28 is attached to a take-up spool, not shown, in the camera 36 and the spool is windingly rotated to wind the protruding forward end portion onto the take-up spool and to unwind the remaining portion of the film leader 28 that forms the outermost convolution of the film roll 26 off the film roll and onto the take-up spool. As the film leader 28 is moved out of the housing 12 and towards the take-up spool, a leader hole 50 substantially rearward in the film leader is advanced off the film roll 26 and into the film exit slit 14. When the leader hole 50 begins to emerge from the film exit slit 14, the end hook 46 drops into the leader hole to engage the leading end portion 42 of the cover strip 40 to the film leader 28. Then, the leading end portion 42 of the cover strip 40 is moved in engagement with the film leader 28. Consequently, the remaining trailing portion 44 of the cover strip 40 is pulled out of the pocket 48 to successively uncover the &#34;FILM USED&#34; indicator 38 and the &#34;FILM LOADED&#34; indicator 32. See FIGS. 1-9. Thus, as shown in FIGS. 2, 4, 5 and 7, the &#34;FILM LOADED&#34; indicator 32 is not uncovered until the film leader 28 is substantially removed from the housing 12. This serves to verify that enough of the filmstrip 18 , i.e. 3-4 frame lengths, has been unwound from the film spool 16 to wind the film leader 28 onto the take-up spool in order to accomplish film loading in the camera 36. 
     Alternate Embodiments 
     FIGS. 10-13 show a first alternate embodiment of the cartridge 10. The same reference numbers as used in FIGS. 1-7 are used in FIGS. 10-13, to indicate the various components. 
     The only difference between the cartridge 10 in FIGS. 1-7 and the cartridge 10 in FIGS. 10-13 is that in FIGS. 10-13 the remaining trailing portion 44 of the cover strip 40 has a t-shaped end stop 52 that is intended to abut a pair of spaced stop lips 54 of the pocket 48 to prevent the remaining trailing portion from being pulled completely out of the pocket as shown in FIGS. 11 and 12. 
     The operation of the cartridge 10 in FIGS. 10-12 is somewhat similar to the operation of the cartridge 10 in FIGS. 1-7. The protruding forward end portion 30 of the film leader 28 is attached to a take-up spool, not shown, in the camera 36 and the spool is windingly rotated to wind the protruding forward end portion onto the take-up spool and to unwind the remaining portion of the film leader 28 that forms the outermost convolution of the film roll 26 off the film roll and onto the take-up spool. As the film leader 28 is moved out of the housing 12 and towards the take-up spool, the leader hole 50 substantially rearward in the film leader is advanced off the film roll 26 and into the film exit slit 14. When the leader hole 50 begins to emerge from the film exit slit 14, the end hook 46 drops into the leader hole to engage the leading end portion 42 of the cover strip 40 to the film leader 28. Then, the leading end portion 42 of the cover strip 40 is moved in engagement with the film leader 28. Consequently, the remaining trailing portion 44 of the cover strip 40, except for the t-shaped end stop 52, is pulled from the pocket 48 to successively uncover the &#34;FILM USED&#34; indicator 38 and the &#34;FILM LOADED&#34; indicator 32. See FIGS. 10-12. Thus, the &#34;FILM LOADED&#34; indicator 32 is not uncovered until the film leader 28 is substantially removed from the housing 12. This serves to verify that enough of the filmstrip 18 , i.e. 3-4 frame lengths, has been unwound from the film spool 16 to wind the film leader 28 onto the take-up spool in order to accomplish film loading in the camera 36. 
     Further winding of the film leader 28 onto the take-up spool causes the leader hole 50 to become separated from the end hook 46. See FIG. 12. The end hook 46 is flexible, which allows it to be straightened to escape the leader hole 50 without damaging the annular region of the film leader 28 surrounding the leader hole. Once the end hook 46 is out of the leader hole 50, it recovers its original curved shape as shown in FIG. 12. 
     Alternatively, as shown in FIG. 13, the end hook 46 has a line of weakness 56 which allows the end hook to be straightened to escape the leader hole 50 without damaging the annular region of the film leader 28 surrounding the leader hole. When the end hook 46 is out of the leader hole 50, it tends to remain straightened rather than recover its original curved shape. 
     FIGS. 14 and 15 show a second alternate embodiment of the cartridge 10. The same reference numbers as used in FIGS. 1-7 are used in FIGS. 14 and 15, to indicate the various components. 
     The only difference between the cartridge 10 in FIGS. 1-7 and the cartridge 10 in FIGS. 14 and 15 is that in FIGS. 14 and 15 the leading end portion 44 of the cover strip 40 has a tacky or adhesive underside region 58 adjacent the end hook 46 that as shown in FIG. 14 contacts a waxy or slippery region 60 on the exterior of the housing 12 to temporarily adhere the leading end portion to the exterior of the housing, to hold the remaining trailing portion 44 of the cover strip over the &#34;FILM LOADED&#34; indicator 32 and the &#34;FILM USED&#34; indicator 38 with the end hook 46 at the film exit slit 14. The waxy region 60 preferably is a piece of wax paper that is fixed at one end to the exterior of the housing 12 and can be partially peeled away from the exterior of the housing as shown in FIG. 15. 
     The operation of the cartridge 10 in FIGS. 14 and 15 is somewhat similar to the operation of the cartridge 10 in FIGS. 1-7. The protruding forward end portion 30 of the film leader 28 is attached to a take-up spool, not shown, in the camera 36 and the spool is windingly rotated to wind the protruding forward end portion onto the take-up spool and to unwind the remaining portion of the film leader 28 that forms the outermost convolution of the film roll 26 off the film roll and onto the take-up spool. As the film leader 28 is moved out of the housing 12 and towards the take-up spool, the leader hole 50 substantially rearward in the film leader is advanced off the film roll 26 and into the film exit slit 14. When the leader hole 50 begins to emerge from the film exit slit 14, the end hook 46 drops into the leader hole to engage the leading end portion 42 of the cover strip 40 to the film leader 28. Then, the leading end portion 42 of the cover strip 40 is moved in engagement with the film leader 28 to first partially peel the wax paper 60 off the exterior of the housing 12 , then to separate the tacky region 58 from the wax paper, and then to relocate the tacky region on the film leader 28 adjacent the leader hole 50. The remaining trailing portion 44 of the cover strip 40 is pulled from the pocket 48 to successively uncover the &#34;FILM USED&#34; indicator 38 and the &#34;FILM LOADED&#34; indicator 32. See FIGS. 10-12. Thus, the &#34;FILM LOADED&#34; indicator 32 is not uncovered until the film leader 28 is substantially removed from the housing 12. This serves to verify that enough of the filmstrip 18 , i.e. 3-4 frame lengths, has been unwound from the film spool 16 to wind the film leader 28 onto the take-up spool in order to accomplish film loading in the camera 36. 
     The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. For example, a second leader hole identical to the leader hole 50 can be provided in the film leader 28 closely behind the first hole to allow the end hook 46 to drop into the second hole in the event the end hook fails to drop into the first hole. This further ensures engagement of the film leader 28 with the leading end portion 42 of the cover strip 40. Alternatively, more than one end hook 46 can be provided to simultaneously drop into respective leader holes. 
     PARTS LIST 
     10. film cartridge 
     12. housing 
     14. slit 
     16. film spool 
     18. filmstrip 
     20. film perforations 
     22. longitudinal film edges 
     24. film roll 
     26. film inner end portion 
     28. film leader 
     30. protruding forward end portion 
     32. &#34;FILM LOADED&#34; indicator 
     34. rear window 
     36. camera 
     38. &#34;FILM USED&#34; indicator 
     40. cover strip 
     42. leading end portion 
     44. remaining trailing portion 
     46. end hook 
     48. pocket 
     50. leader hole 
     52. end stop 
     54. stop lips 
     56. line of weakness 
     58. tacky region 
     60. waxy region