Abstract:
A system and method for pre-setting the counter wheel orientation in a camera pre-loaded with film is provided. Alignment indicia on the counter wheel are arranged during assembly to determine at various positions relative to the camera metering system whether the counter silk screen has been properly aligned and the counter properly preset.

Description:
PRIORITY 
     The present application claims priority from co-pending provisional patent application Ser. No. 60/400,917, filed on Aug. 2, 2002 and entitled FILM COUNTER WHEEL AND METHOD FOR PRESETTING THE FILM COUNTER WHEEL DURING FILM PRE-LOADING. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of cameras and, more particularly, to a system and method for pre-setting the counter wheel in a camera pre-loaded with film. 
     BACKGROUND OF THE INVENTION 
     Inexpensive cameras, such as single use cameras, have been provided which are pre-loaded with film in the factory and provided to the consumer ready for use. The film counter has usually been set to count down from the maximum number of exposures available on the camera back to zero. In this way, a consumer merely needs to look through the film counter window to determine how many pictures remain, without having to do the math or remember how many exposures were available initially on the roll. 
     However, it is difficult to set the counter wheel to the appropriate position during film pre-loading if the pre-loading is accomplished after the camera is assembled. The numbers silkscreened on the counter wheel must show the appropriate number of exposures remaining after the film has been pre-wound. 
     What is needed is a simple but accurate system and method for pre-setting the film counter wheel when pre-loading film into a camera. This object, as well as others, is satisfied by the present inventions. 
     SUMMARY OF THE INVENTION 
     A system and method for pre-setting the counter wheel orientation in a camera pre-loaded with film is provided. Alignment indicia on the counter wheel are arranged during assembly to determine at various positions relative to the camera metering system whether the counter silk screen has been properly aligned and the counter properly preset. 
     Other objects and advantages of the present invention will become more readily apparent in the description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings an exemplary embodiment that is presently preferred, it being understood however, that the invention is not limited to the specific methods and instrumentality&#39;s disclosed. Additionally, like reference numerals represent like items throughout the drawings. In the drawings: 
     FIG. 1 is a rear perspective view of a camera having various parts removed and other parts exploded to more clearly show certain subsystems of the camera. 
     FIG. 2 is an enlarged perspective view of the sprocket assembly of the camera of FIG.  1 . 
     FIG. 3, is a top plan view of the certain film advance/metering subsystem components of the camera as found in the camera of FIG.  1 . 
     FIG. 4 is a partial perspective view of a the internal counter subsystem of a camera in accordance with one embodiment of the present invention. 
     FIG. 5 is a top plan diagram of the sprocket cams relative to the counter wheel in accordance with one particular embodiment of the present invention. 
     FIG. 6 is a top plan cutaway diagram of the counter wheel relative to the sprocket cams in accordance with one particular embodiment of the present invention. 
     FIG. 7 is a top plan view of a portion of a camera in accordance with one embodiment of the present invention. 
     FIG. 8 is a perspective view of a portion of a camera in accordance with one embodiment of the present invention. 
     FIG. 9 is a top plan view of a portion of a camera in accordance with one embodiment of the present invention. 
     FIG. 9A is an enlarged view of a portion of FIG. 9 having the counter wheel removed. 
     FIG. 9B is an enlarged view of a portion of FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before explaining the disclosed embodiments of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. 
     Certain cameras, such as single use cameras, are pre-loaded with film in the factory and provided to the consumer ready for use. Traditionally, pre-loaded cameras include a film counter wherein the film counter wheel has a printed set of numbers showing the number of available exposures remaining in the camera. A counter wheel and method are provided to permit the film counter wheel to be preset to a specific location during film pre-loading. The counter wheel is formed with at least one hole therethrough to provide for alignment of the counter wheel as necessary to align the counter wheel for film preloading and ensure proper alignment of the silk screening. 
     Referring now to FIGS. 1-9B, there is shown a camera in accordance with the present invention. Referring more particularly to FIG. 1, there is shown a rear perspective view of a camera  10  including an exploded portion and having parts removed to more clearly show features of the film advance/metering, anti-reversal and exposure subsystems. Camera  10  includes a main body portion  12  located between a front cover  14  and a rear cover (not shown). Main body portion  12  is molded to contain a film cassette receiving chamber in which is placed a film cassette  16  and a take-up spool chamber  18 . The take-up spool chamber  18  is designed to receive a spool  20  therein. The bottom portion of the spool  20  includes a socket  20   a  designed to extend through the outer covers and engage a rotatable tool for pre-winding the film. One such film pre-winding method is described in U.S. Pat. No. 6,226,457, that patent being incorporated herein. 
     Mounted on or integral with the body  12  are portions of the film transport and metering system, as well as the anti-reversal pawl  21 . Anti-reversal pawl  21  is designed to engage the teeth on the advance wheel  28  to permit winding in only the film advance direction. Attempting to wind the film in the pre-wind direction will cause the pawl end of the anti-reversal pawl  21  to lodge between adjacent teeth of the advance wheel  28  preventing movement of the advance wheel in that direction. 
     A film advance/metering subsystem is mounted on the main body  12  and includes the film advance wheel  28 , a striker  26  mounted on the body  12  via post  22 , a release claw  24 , the sprocket assembly  30 , the counter wheel  40  and top plate  50 . Sprocket assembly  30  includes a sprocket  34 , which extends into the film path through the main body  12  in order to engage the film. As shown more specifically in FIG. 2, the sprocket  34  is attached to a sprocket shaft  32 . In one embodiment the sprocket shaft  32  connects to the sprocket  34  at a square hole formed in the sprocket  34 . Additionally fixed to the sprocket shaft  32  are the primary cam  36  including a notch  36   a  and a secondary cam  38 . The sprocket assembly  30  is positioned so that when engaged, a finger on the striker  26  follows the outer surface of the secondary cam  38  to rotate the striker  26  back to the charged position, while a follower finger  24   a  follows the outer surface of the cam  36  during film advance. The cams  36 ,  38  are secured to the shaft  32  and rotate with the sprocket  34 , one revolution for each film frame. Sprocket shaft  32  additionally includes a single tooth  32   a  and a pin portion  32   b  as will be described more fully herebelow. 
     Striker  26  and the release claw  24  are both spring biased into their normal positions by torsion springs, not shown. The striker  26  includes a tab  26   a  and a cam follower finger  26   b . Release claw  24  includes, among other features, a follower finger  24   a , shoulder  24   b , spur portion  24   c , trigger plate  24   d  and pawl  24   e . The release claw  24  is normally spring biased such that follower finger  24   a  follows the outer surface of the cam  36  after a film frame exposure is wound into the film cassette  16 . When the camera is readied for the next exposure, the follower finger  24   a  is forced all the way into the notch  36   a , the striker tab  26   a  rests against the release claw shoulder  24   b  and the pawl end  24   e  of the release claw  23  is lodged between adjacent teeth of the advance wheel, preventing the advance wheel from further movement. A leg (not shown) on the top plate  50  contacts the trigger plate  24   d  when the trigger button  50  is depressed, releasing the release claw and permitting the striker to return to its normal condition, thus momentarily opening the shutter as it passes. 
     The counter wheel  40  sits on the post  22  that centers the striker  26 . Additionally, the counter wheel is held in place by the top plate  50 . Top plate  50  is matingly engaged with the main body  12  of the camera  10 . A hole  54  in the top plate engages the pin end  32   b  of the sprocket shaft  32 . The number of frames remaining indicated on the counter wheel can be viewed through the counter window  52  formed in the top plate  40 . When assembled, window  52  extends through an aperture in the front and rear covers of the camera  10 . Alignment holes  41  and  56  pass through the counter wheel and top plate, respectively. Additionally, in one preferred embodiment, the counter wheel  40  additionally includes at least a second alignment indicia indicated by the holes  43   a ,  43   b  and  43   c . If desired, additional alignment indicia, such as alignment arrow  44 , may be provided to assist in setting the counter. 
     On the back side of the counter wheel  40 , a wedge shaped protrusion  47  extends from the central hole  45 , opposite the alignment hole  41 . Numbered indicia, such as indicia  48 , are silk-screened on the counter wheel. Teeth, such as tooth  49  are evenly spaced on the outer perimeter of the counter wheel  40 . 
     A method of setting the counter wheel  40  will now be described. Initially, with both covers removed from the camera, the sprocket shaft should be locked by the release claw, as shown in FIG.  3 . When locked, the follower finger  24   a  rests in the notch  36   a  and the release claw shoulder  24   b  abuts the striker tab  26   a , additionally placing the striker in the loaded position. 
     After the sprocket shaft is locked, the counter wheel is centered on the shaft  22 , such that the striker shaft is aligned with the alignment marks  43   c  and  44 , as more particularly shown in FIG.  5 . After roughly aligning the sprocket shaft with the first alignment indicia  44 , to ensure that the counter wheel  40  is fully aligned, the counter wheel  40  may be pushed slightly clockwise until the wedge shaped protrusion  47  on the under side of the counter wheel  40  abuts the tab  24   c  of the release claw ( 24  of FIG.  3 ), as shown in area “x” of FIG.  6 . Alternatively, the counter wheel  40  may include an indent and the release claw  24  may include a protuberance that mates with the indent when the counter wheel  40  is rotated. Preferably, the counter wheel  40  is turned using the finger of a person assembling the camera, although mechanical means may be used. Once the protrusion  47  engages the tab  24   c , the counter wheel  40  will be locked into place by the release claw  24 . 
     After locking the counter wheel  40  in place, the top plate  50  may be mated with the main body  12  of the camera  10  while still ensuring the alignment of the sprocket shaft pin  32   b  with the alignment hole  43   c , as shown in FIG.  7 . Additionally, sprocket shaft pin  32   b  will pass through the hole  54  of the top plate  50  as shown in FIGS. 7 and 8. 
     After the top plate  50  has been locked to the main body  12 , the front cover  14  may be placed on the main body  12  to ready the camera  10  for testing. Referring more specifically to FIGS. 9,  9 A and  9 B, with the front cover on, the sprocket assembly  30 , and correspondingly the striker  26  and release claw  24  are moved to the film pre-load position. More specifically, the sprocket shaft is rotated, preferably by hand, until the follower finger  26   b  of the striker  26  rests in the “v” groove  38   a  of the secondary cam  38 , as shown in FIG.  9 A. The hole  56  in the top plate  50  should be aligned with the hole  41  in the counter wheel  40 . Additionally, the sprocket shaft  32  may then align with the alignment indicia  46 . 
     The film leader is pulled from the film cassette  16 , passed over the sprocket  34  and attached to the spool  20 . While the holes  56  and  41  still aligned and the shaft  32  aligned with the alignment indicia  46 , the back cover of the camera is snapped on and the camera is readied for pre-winding. At this time, if desired, the alignment indicia  43   c  may be provided in the counter window  52  as a quality control check, as shown more particularly in FIG.  9 B. The assembled camera is then loaded onto a pre-winding fixture and the anti-reversal pawl and metering system may be disengaged as described in the previously incorporated &#39;457 patent or in my co-pending, commonly assigned patent application entitled DISENGAGEMENT MECHANISM FOR FILM PRE-LOADING AND FILM PRE-LOADING METHOD, based from provisional patent application No. 60/400,628 and filed on even date herewith, that application being incorporated herein by reference. During pre-winding, a rotatable tool (not shown) is engaged with the spool socket  22  and rotated to pre-wind the film onto the spool  20 . 
     As the film is being pre-wound, the sprocket assembly is being rotated one revolution per film frame. Once each revolution, the tooth  32   a  on the sprocket shaft  32  engages a tooth  49  on the counter wheel and rotates the counter wheel by one frame count. After the film is completely pre-wound onto the spool  20 , the counter window  52  will show the proper film count and, if desired, the alignment indicia  43   a  for quality control purposes. Alternately, if an additional frame is included to provide a test shot for quality control purposes, the counter window  52  will show no frame number, but after the test frame is shot, the proper counter number will appear in the counter window  52 . At this time the camera  10  is ready for use by the consumer. 
     While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.