Abstract:
A camera frame assembly has a base member and a drive hub connected to the base member. A shutter is joined to the drive hub. A shutter driver is mounted to the base member. The shutter driver selectively deflects from a charged state to a discharged state and impacts the drive hub during the deflecting. The drive hub and shutter pivot together relative to the base member in a discharge direction about the pivot axis, responsive to the impacting, from a shutter closed position to a shutter open position. The drive hub is pivotable, in a recharge direction opposite the discharge direction, independent of the shutter.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______, [Attorney Docket No. 85329RLW], entitled: MULTIPLE POSITION LENS BARREL HAVING CAM CYLINDER WITH COMMONLY BIASED FIRST AND SECOND LENS CARRIERS, filed Oct. 4, 2002, in the name of Anthony Dirisio.  
         [0002]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______, [Attorney Docket No. 85549RLW], entitled CAMERA LENS MODULE HAVING RECYCLABLE LENS BARREL CAP, filed ______, in the name of Anthony Dirisio.  
         [0003]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______ , [Attorney Docket No. 85552RLW], entitled: EXTENDABLE LENS CAMERA HAVING MECHANICAL SHUTTER BLOCKING IN INTERMEDIATE LENS POSITIONS, filed ______, in the name of Anthony Dirisio.  
         [0004]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______, [Attorney Docket No. 85533RLW], entitled: CAMERA FRAME ASSEMBLY HAVING FOUR-BAR LINKAGE SHUTTER ACTUATOR, filed ______, in the name of Anthony Dirisio, which is hereby incorporated herein by reference.  
         [0005]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______, [Attorney Docket No. 85554RLW], entitled: CAMERA FRAME ASSEMBLY HAVING SHUTTER ACTUATOR WITH TELESCOPING STRIKER AND METHOD, filed ______, in the name of David J. Cornell, which is hereby incorporated herein by reference.  
         [0006]    Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. ______, [Attorney Docket No. 85553RLW], entitled: CAMERA FRAME ASSEMBLY HAVING SHUTTER THAT SLIDES FORWARD AND BACK WITH ZOOM LENS, filed ______, in the name of Anthony Dirisio, David J. Cornell, which is hereby incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0007]    The invention relates to photography and photographic cameras and more particularly relates to camera frame assemblies having an independently back-pivoting drive hub for an impact shutter.  
         BACKGROUND OF THE INVENTION  
         [0008]    One-time-use cameras and other simple cameras commonly use an impact shutter. These shutters are operated by a shutter driver (sometimes called a “high energy lever”) that strikes a tang or shoulder of a shutter blade. The shutter driver can slide, but is more typically rotated to strike the shutter blade. The shutter driver is spring operated and is charged by the winding of a film transport and winding mechanism that advances film simultaneously with moving the shutter driver to a charged position. These functionalities make it convenient to provide the shutter driver near the film. On the other hand, the shutter is most conveniently placed at some distance from the film at the end of a baffle enclosing the cone of light entering through the taking lens. This distance has to be spanned, for the shutter driver to impact the shutter.  
           [0009]    After the shutter has been opened by movement of the shutter driver from a charged position to a discharged position, the shutter driver must be recharged for the next picture taking event, by returning to the charged position from the discharged position. In striking the shutter, the striker of the actuator driver moves in a plane that parallels both a pivot axis of the shutter and the optical axis of the taking lens of the camera. During recharging, the striker moves in the same plane and the shutter moves out of the way. In many one-time-use cameras, the shutter is tilted or translated out of alignment with the pivot axis. For example, U.S. Pat. No. 5,614,975 discloses a camera, in which the shutter blade has a large slot that receives a post extending outward from the frame. During recharging, the striker pushes the shutter, moving the post along the slot and the shutter out of alignment with the pivot axis. This approach risks light leakage when the shutter is moved.  
           [0010]    U.S. Pat. No. 5,721,995 discloses use of a series of links to trip a pair of impact shutter blades.  
           [0011]    It would thus be desirable to provide an improved camera frame assembly in which the shutter driver recharging presents a reduced risk of light leakage due to shutter movement.  
         SUMMARY OF THE INVENTION  
         [0012]    The invention is defined by the claims. The invention, in broader aspects, provides a camera frame assembly has a base member and a drive hub connected to the base member. A shutter is joined to the drive hub. A shutter driver is mounted to the base member. The shutter driver selectively deflects from a charged state to a discharged state and impacts the drive hub during the deflecting. The drive hub and shutter pivot together relative to the base member in a discharge direction about the pivot axis, responsive to the impacting, from a shutter closed position to a shutter open position. The drive hub is pivotable, in a recharge direction opposite the discharge direction, independent of the shutter.  
           [0013]    It is an advantageous effect of the invention that an improved camera frame assembly is provided in which the shutter driver recharging presents a reduced risk of light leakage due to shutter movement. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying figures wherein:  
         [0015]    [0015]FIG. 1 is a front perspective view of the shutter mechanism and some other parts of an embodiment of the camera frame assembly. The shutter is in a rear position and charged state. A flash unit is indicated diagrammatically. Parts of the frame and lens shroud are shown.  
         [0016]    [0016]FIG. 2 is a top view of the shutter mechanism of FIG. 1. Also shown are the winding mechanism and a film cartridge. The thumbwheel is partially cut-away.  
         [0017]    [0017]FIG. 3 is the same view as FIG. 1, but the shutter is in a front position and the flash unit is not shown.  
         [0018]    [0018]FIG. 4 is a front view of the shutter mechanism and winding mechanism of FIG. 2. The shutter mechanism is in a charged state.  
         [0019]    [0019]FIG. 5 is the same view as FIG. 3, but the shutter is in an opened state.  
         [0020]    [0020]FIG. 6 is the same view as FIG. 3, but the shutter mechanism is transitioning to a recharged state.  
         [0021]    [0021]FIG. 7 is a front perspective view of the camera frame assembly of FIG. 1.  
         [0022]    [0022]FIG. 8 is a partially exploded front perspective view of the camera of FIG. 7. For clarity, some parts associated with the frame are not shown.  
         [0023]    [0023]FIG. 9 is an exploded, front perspective view of the lens module of the camera of FIG. 7. The front lens retainer is not shown.  
         [0024]    [0024]FIG. 10 is a cross-sectional view of the lens module and part of the frame of the camera of FIG. 7.  
         [0025]    [0025]FIG. 11 is a front perspective view of another embodiment of the camera frame assembly.  
         [0026]    [0026]FIG. 12 is an exploded, front perspective view of the lens module of the camera of FIG. 11.  
         [0027]    [0027]FIG. 13 is the same view as FIG. 1, of a modified shutter mechanism.  
         [0028]    [0028]FIG. 14 is the same view as FIG. 1, of another modified shutter mechanism.  
         [0029]    [0029]FIG. 15 is a front perspective view of the shutter blade, return spring and drive hub of still another modified shutter mechanism.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    A camera frame assembly  10  includes a shutter mechanism  12  that has a shutter  14 , which moves back and forth along an optical axis  16  with a lens barrel  18 . The term “camera frame assembly  10 ” is used here to refer to a complete camera or an incomplete subunit of a camera that can be assembled with other parts to form a complete camera. The invention is particularly advantageous in relation to a camera frame assembly  10  that is a complete or incomplete one-time use camera.  
         [0031]    The camera frame assembly  10  has a frame or base member  20  and a lens module  22  attached to the base member  20 . In the embodiments illustrated, the base member  20  is held between front and rear covers  21 , 23  of the camera frame assembly  10  and the lens module  22  extends through an opening in the front cover. Referring to FIG. 8, the base member  20  has a pair of opposed chambers  72 , one can hold a film cartridge (not shown) and the other a film roll. A winding mechanism  40  advances film from the film roll, across a capture plane  38  (indicated by a dashed line in FIG. 7), and back into the film cartridge. A flash unit  164  can be included and synchronized with the shutter. A viewfinder-keeper plate  166  holds parts of the winding mechanism  40  on the frame. The flash unit  164  and other components are mounted to the base member  20  or held between the base member  20  and covers  21 , 23 .  
         [0032]    The lens module  22  has a lens base  24  that is mounted in a fixed position on the base member  20 . (The term “fixed” and like terms are used herein in the sense of a physical position or relationship that is in immobile and unchanging.) The lens base  24  defines the optical axis  16 . In particular embodiments of the invention, the lens base  24  includes a carrier  26  and a base lens clement  28  (shown in FIG. 10) and optionally includes one or more additional lens elements (not shown).  
         [0033]    In the embodiment shown in FIGS.  1 - 10 , the lens base  24  includes the carrier  26 , a mount  27 , and a holder-cap  29 . The mount  27  joins the lens module  22  to the frame  20  and is configured so meet the requirements of a particular frame design. The mount  27  is fixed to the frame  20 . The manner in which the mount  27  and other parts are attached to the frame  20  is not critical. For example, the mount  27  can be attached by a friction fit or by hooks or can be otherwise fastened or adhered or bonded.  
         [0034]    The mount  27  has a forward-facing cup  35  (see FIG. 9) that receives the holder-cap  29 . A central opening  37  of the mount  27  can be bordered by a masking structure  39  that blocks unwanted light, so reducing flare. The holder-cap  29  is snapped, adhered, or otherwise fastened in fixed relation to the mount  27 . The holder-cap  29  covers the lens barrel  18  such that the lens barrel  18  extends and retracts within the holder-cap  29 . (See FIG. 9.) In this embodiment the front cover covers the base member  20  and the lens module  22 , as shown in FIG. 7.  
         [0035]    In an alternative embodiment, shown in FIGS.  11 - 12 , the lens base  24  includes a holder  43  in place of the holder-cap  29 . The holder  43  is similar to the rear portion of the holder-cap  29 . The lens barrel  18  extends out of and retracts back into the holder  43 . The end of the traveler  32  is covered by a separate cap  36 , in this embodiment. The traveler  32  is lengthened relative to the traveler  32  of the embodiment of FIGS.  1 - 10 .  
         [0036]    The lens barrel  18  is joined to the lens base  24 . The lens barrel  18  is movable forward and backward (indicated by double-headed arrow  30 ) along the optical axis  16  between a fully extended position and a fully retracted position. The movement of the lens barrel  18  may or may not include rotation about the optical axis  16 .  
         [0037]    The lens barrel  18  includes the traveler  32  and a front lens element  34  held by the traveler  32 . The lens barrel can also include a front lens retainer  33  to hold the lens in place. In the embodiment shown in FIGS.  11 - 12 , the lens barrel  18  includes a barrel cap  36  that replaces the lens retainer  33  and closes the forward end of the traveler  32 . Optionally, one or more additional lens elements (not shown) are located within the traveler  32 . The front and rear lens elements  34 , 26  and other lens elements (if any) together comprise a taking lens system that directs light to the capture plane  38 . The cameras are described herein in relation to embodiments having photographic film as capture media. An electronic imager (not shown) can be substituted for the photographic film.  
         [0038]    In the illustrated embodiments, the traveler  32  has a cylindrical outside wall  42  and a cross wall  44  extending in a direction perpendicular to the optical axis  16 . The cross wall  44  has a central opening and supports a front lens element  34 . The shutter  14  is trapped between the cross wall  44  and a backer  71  that is joined to the outside wall  42  of the traveler  32 . The backer  71  can be press fit or adhered or attached by fasteners or the like.  
         [0039]    A twist ring  56  is mounted on the lens base  24 . The twist ring  56  extends at least part of the way around the lens base  24 . The twist ring  56  is reversibly rotatable relative to the lens base  24  from a rightward configuration through a plurality of intermediate configurations to a leftward configuration. (As with other directional terms herein, the terms “rightward” and “leftward” are used in a relative sense and are not limiting.) The twist ring  56  is mechanically coupled to the traveler  32 , such that rotation of the twist ring  56  between the rightward and leftward configurations moves to the lens barrel  18  between the first and second positions, respectively. The twist ring  56  is trapped in place axially by a taper or internal feature of the holder-cap  29  in the embodiment of FIGS.  1 - 10  and by a forward rim  51  of the holder  43 , in the embodiment of FIGS.  11 - 12 .  
         [0040]    The traveler  32  includes a connector  50  that along with parts of the lens base  24  and twist ring  56  provides an extension-retraction mechanism. The connector  50  has three track followers  54 . The track followers  54  can be equally spaced about the traveler  32  to help prevent the traveler  32  from canting relative to the lens base  24 . Each track follower  54  has a pair of spaced apart posts. The twist ring  56  has an engagement portion  58  that receives the connector  50  of the traveler  32  and constrains of the traveler  32  such that the traveler  32  moves forward and backward along the optical axis  16  when the twist ring  56  is rotated between the rightward and leftward configurations. The engagement portion  58  is a set of internal tracks  60  that each receive one of the track followers  54  of the traveler  32 . In the embodiments illustrated herein, the tracks  60  are spiral ribs that extend toward the optical axis from the circumferential wall  67  of the twist ring  56 . The tracks  60  are gripped between the posts of the respective track followers  54 . Alternatively, tracks  60  can be grooves or pairs of parallel fences that receive track followers  54  configured to ride in the grooves or between the fences.  
         [0041]    The track followers  54  extend to the tracks  60  through corresponding slots  63  in the holder-cap  29  or holder  43  of the lens base  24 . The slots  63  each extend parallel to the optical axis  16 . In the illustrated embodiments, there are three slots  63  and three corresponding track followers  54 .  
         [0042]    The track followers  54  slide along the tracks  60  when the twist ring  56  is rotated. Since the track followers  54  are held by the slots  63  of the lens base  24 , this results in the lens barrel  18  traversing linearly inward or outward along the optical axis  16 . After movement, the traveler  32  is held in a selected position by friction.  
         [0043]    The engagement portion  58  and corresponding connector  50  can also be changed. For example, the engagement portion  58  and connector  50  can be meshed gears or the equivalent. Other mechanisms for retracting and extending a lens barrel using a twist ring are known to those of skill in the art.  
         [0044]    The lens barrel movement is manually powered by the user rotating the twist ring  56 . Referring to FIG. 1, the twist ring  56  includes a knob  41  that protrudes through a slot  73  in the front cover  21 . The knob  41  is moved by the user to rotate the twist ring  56 . The lens barrel  14  can be operated manually in another manner and, alternatively, can be powered rather than being operated manually.  
         [0045]    The carrier  26  has a base lens seat  49 . The base lens element  28  is seated in the base lens seat  49  and is held in place by a retainer  47  that if pressed over the base lens seat  49 . The base lens element  28  can, alternatively, be fastened or adhered in some other manner. The carrier  26  has pegs  53  that extend outward in the same manner as the track followers  54  of the traveler  32 . The pegs  53  are trapped within respective slots  63  of the holder  43  rearward of respective track followers  54 . Three pegs  53  are provided on the same basis as the three track followers  54  of the traveler  32 .  
         [0046]    The twist ring  56  has a rear margin  55  that is shaped into three cam surfaces  57  (a cam surface is shown in FIG. 10) that face respective pegs  53 . When the twist ring  56  is rotated, the pegs  53  move against respective cam surfaces  57 . The movement is constrained by the slots  63 , such that the carrier  26  cannot rotate about the optical axis  16 . The lens module can, optionally, bias the carrier against the cam surfaces or the traveler against the tracks, or both using springs or elastomer members (not shown).  
         [0047]    The shutter mechanism  12  is opened to direct light through a taking lens system to the capture plane  38 . The figures illustrate a photographic film type camera, but the camera can use an electronic imager rather than photographic film for archival capture of images.  
         [0048]    The shutter mechanism  12  includes a shutter release  62  that is mounted to the frame  20  and an impact shutter  14  that is disposed in the traveler  32 . The shutter  14  is generally described herein in terms of a single blade, but a system of multiple blades can be substituted for the single blade, if desired. The shutter  14  moves forward and back along the optical axis  16  with the traveler  32 . The shutter  14  is normally in a closed state in which the shutter  14  tightly covers an aperture  64  in the cross wall  44  of the traveler  32 . The shutter  14  is driven by a shutter driver  66  (sometimes referred to as a “high energy lever”). The shutter driver  66  is charged by the winding mechanism  40  to a charged state.  
         [0049]    The winding mechanism  40  includes a combined thumbwheel and metering wheel  68  that is mounted for rotation adjacent a top corner of the frame  20 . A portion of the wheel  68  extends beyond the rear cover  23  and is accessible to the camera operator. If desired, rather than being driven directly by the user, the wheel  68  can be driven by a winding knob, lever, electric motor or other like device.  
         [0050]    Photographic film  70  is initially wound in a coil in one film chamber  72  and extends across the capture plane  38  to another film chamber  72 , in which an end of the film is held by the spool  75  of a film cartridge  76 . The wheel  68  has a key that couples the wheel  68  to the film cartridge spool  75 , such that forward rotation of the wheel  68  causes the film to be wound into the cartridge  76  and advanced past the capture plane  38 . An anti-backup pawl  78  is resiliently biased against an edge of the wheel  68  to prevent rotation in a reverse direction.  
         [0051]    A film metering sprocket  80  has a sprocket shaft  81  that is pivotably supported by the frame  20 . The sprocket  80  engages perforations in the film  70  and is rotated through a complete revolution each time the film  70  is advanced by a distance corresponding to one film frame.  
         [0052]    An actuator disk  82  and a charging cam  84  are made in one piece with the sprocket  80  or are assembled with the sprocket  80  so as to remain in fixed (immobile) relation. The actuator disk  82  has a otherwise continuous circumference interrupted by a notch  85 . The charging cam  84  has a spiral surface on one side and a spiral surface on the other side.  
         [0053]    A film metering lever  86  is supported for pivotal movement by the frame  20 . (The metering lever  86  and shutter driver  66  are illustrated as having empty, cylindrical cores that can receive upwardly extending posts provided on the frame  20 . The metering lever  86  and shutter driver  66  can instead have shafts that fit in holes in the frame  20  and keeper plate  166 .) The metering lever  86  is biased by a coil spring  88  in an activating direction. The metering lever  86  has a first arm  90  ending in a tooth and a second arm  92  having a pawl. When the toothed arm  90  of the metering lever  86  is received in the notch  85  of the actuator disk  82 , the pawl arm  92  of the metering lever  86  engages the toothed rim of the wheel  68  temporarily blocking advancement of the film  70 .  
         [0054]    The shutter release member  62  includes a shutter button  94  that is located near the cantilevered end of a flexible arm  96  of the shutter release  62 . Adjacent the shutter button  94  the arm  96  has a vertical tab that carries a latch member  98 .  
         [0055]    The shutter driver  66  is biased by a coil spring  100 . The shutter driver  66  has a tongue  102  that is engaged by the latch member  98  to hold the shutter driver  66  in a charged position in opposition to the spring  100 . The shutter driver  66  also has a cam follower finger  104  that is positioned so as to engage the charging cam  84 .  
         [0056]    When the shutter driver  66  is in the charged state and the camera is in condition to make an exposure, as shown in FIGS.  1 - 4 , the tongue  102  of the shutter driver  66  is engaged by the latch member  98 , which holds the shutter driver  66  in the charged condition in opposition to the spring  100 . Prior to this during film advance, the sprocket  80  has been rotated into a position in which the toothed arm  90  of the metering lever  86  is in the notch  85  of the actuator disk  82 . This allows the metering pawl arm  92  to engage the wheel  68  under the influence of the spring  100 . The cam follower finger  104  of the shutter driver  66  is out of contact with the charging cam  84 .  
         [0057]    When the photographer depresses the shutter button  94  to initiate an exposure, the shutter release  62  is released from a ready state to a released state. The shutter button  94  moves the latch member  98  out of engagement with the tongue  102  of the shutter driver  66 , the shutter driver  66  is pivoted rapidly by the spring  100  from the charged state to the discharged state. During this movement of the shutter driver  66 , a protruding striker  106  of the shutter driver  66  impacts the tang  108 , causing the shutter  14  to rotate about a pivot axis  110  from a closed state to an open state. This moves the shutter  14  away from the aperture  64  exposing a light image on the capture plane  38 . The aperture  64  is uncovered momentarily. When the striker  106  moves past the tang  108 , the shutter  14  returns to a closed state under the biasing of a shutter return spring  112 . Movement of the the shutter  14  into the closed position is limited by a stop  113 .  
         [0058]    After the film exposure has been completed, the user releases the shutter button  94 . The shutter driver  66  moves into engagement with a downwardly extending yoke  114  of the metering lever  86 . This causes the metering lever  86  to rotate to a deactivated position, by overpowering the weaker force exerted on the metering member  86  by spring  88 . Accordingly, the metering pawl arm  92  is disengaged from the wheel  68  and the metering member tooth arm  90  is retracted from the actuator disc notch  85 . This allows the winding mechanism  40  to be operated to advance the film to the next available frame.  
         [0059]    When the photographer next rotates the wheel  68  forward, the film is wound onto the spool. This causes the metering sprocket  80  to rotate in the same direction. The charging cam  84  engages the finger of the shutter driver  66  and rotates the latter back to a charged position.  
         [0060]    A shaft  116  extends outward from the frame  20  to and, preferably, beyond the shutter  14 . The shaft  116  is longitudinally aligned with the pivot axis  110  of the shutter  14  and is also parallel to the optical axis  16 . Referring now to FIGS.  1 - 9 , in a particular embodiment, the shaft  116  extends outward from the frame  20  and through the cross wall  44  of the traveler  32 . In this embodiment, the shutter  14  has a blocking portion  120  that covers the aperture  64  when the shutter  14  is in a closed state. Joined to the blocking portion  120  is a neck  122  that includes an attachment  118  for the shutter return spring  112 . The other end of the shutter return spring  112  is joined to an attachment (not shown) on the cross wall  44  of the traveler  32 . Joined to the neck  122  of the shutter  14 , opposite the blocking portion  120 , is a slider  124  that can slide back and forth on the shaft  116 . The sliding movement is unconstrained except by the movement of the traveler  32 . The fit between and the slider  124  and the shaft  116  is a such that rotation of the shutter  14  relative to the shaft  116  is precluded. As a result, rotation of the shaft  116  causes the shutter  14  to likewise rotate.  
         [0061]    The slider  124  can extend fully around the shaft  116 , as shown in FIGS.  1 - 9 . The shaft  116  extends through an keyway  126  in the slider  124 . The slider  124  can have other forms. For example, the slider  124  can be a tongue (not shown) that fits through an elongated slot (not shown) in the shaft  116  and slides back and forth within the slot. It is preferred that the fit between the slider and of the shaft  116  have close tolerances. This reduces the risk of vibration or other undesirable movement during opening and closing of the shutter  14 .  
         [0062]    Interior to the shutter  14 , a drive hub  128  is mounted on the shaft  116 . The drive hub  128  has a knuckle  130  through which the shaft  116  extends. Extending out from the knuckle  130  toward the shutter driver  66  is a tang  108 . Extending outward in another direction from the knuckle  130  is an reset arm  132 . Opposite the reset arm  132  is a switch actuator  134 . The drive hub  128  is separate from the shutter  14 . A retainer  136  (shown in FIG. 10) blocks movement of the drive hub  128  along the shaft  116  parallel to the pivot axis  110 . In the illustrated embodiment, the retainer  136  is a portion of the lens base  24 . Other forms of retainer  136  can be provided, such as a protrusion or part (not shown) fitted on the shaft  116  forward of the drive hub  128 .  
         [0063]    During picture taking and recharging, the tang  108  functions in the same manner as a tang  108  that is part of a single-blade impact shutter. That is, when the shutter driver  66  moves from the charged state to the discharged state, the striker  106  of the shutter driver  66  impacts against the tang  108  causing the drive hub  128  to rotate about the pivot axis  110 . The tang  108  can have a portion cutaway to add clearance for movement of the striker  106  past the tang  108  during recharging.  
         [0064]    In the invention herein, the drive hub  128  is spaced from the shutter  14  and acts on the shutter  14  only via of the shaft  116 . When the tang  108  is rotated by the shutter driver  66 , the shaft  116  rotates about the pivot axis  110 . This causes the shutter  14  to rotate and moves the shutter  14  from the closed state to the open state. The shutter return spring  112  is biased by the movement of the shutter  14  from the closed state to the open state. After the striker  106  of the shutter driver  66  has cleared the tang  108 , the shutter return spring  112  causes the shutter  14  to return to the closed state.  
         [0065]    The shaft  116  pivots in a pair of bushings  138 . One of the bushings  138  is provided in the frame  20 . The opposite bushing  138  is provided in the holder-cap  29  (see FIG. 9) or the cap  36  (see FIG. 12) or in the cross wall  44  of the traveler  32  (not shown). The shaft  116  extends through a passage  140  in the knuckle  130  of the drive hub  128 . The passage  140  is oversized and provides for movement of the shaft  116  with the drive hub  128  during discharge of the shutter mechanism  12 , when the tang  108  is struck by the striker  106  of the shutter driver  66 . The passage  140  also allows for movement of the drive hub  128  independent of the shaft  116  during recharging, when the shutter driver  66  is returned to the charged state. In the illustrated embodiment, the shaft  116  is roughly rectangular in cross-section. The larger sides  142  of the shaft  116  are flat and the narrower sides  144  have slight convex curvature. The passage  140  of the knuckle  130  is roughly butterfly shaped in cross-section. Opposed end walls  146  of the passage  140  are concave and match the narrower sides of the shaft  116 . A pair of sidewalls  148  extend between the end walls  146 . Each sidewall  148  has two pivot stops  150 , 152  arranged in a V-shape. One pair of pivot stops  150  contacts the wider sides  142  of the shaft  116  when the shaft  116  is rotated during picture taking. The other pair of pivot stops  152  approaches or contacts the wider sides  142  of the shaft  116  during recharging. (Pivoting of the drive hub  128  during recharging is limited by the resilient bending of the reset arm  132 .)  
         [0066]    The reset arm  132  faces a limit stop  154  that extends out from the frame  20 . The reset arm  132  is spaced from the stop  154  except during recharging. At that time, as shown in FIG. 6, the reset arm  132  presses against the stop  154 . The reset arm  132  is resilient. During recharging, when the striker  106  clears the tang  108 , the reset arm  132  propels the drive hub  128  in the direction of arrow  157 . This pivots the drive hub  128  relative to the shaft  116 , from a recharging position in which the first wider side  142  of the shaft  116  presses against the first pair of pivot stops  150  of the knuckle  130  passage  140  to a ready position in which the second wider side  142  of the shaft  116  presses against the second pair of pivot stops  152 . This is done to provide a quicker response of the drive hub  128  to the striking movement of the shutter driver  66 , during shutter mechanism  12  discharge. Resilience of the reset arm  132  can be provided in any convenient manner. In the illustrated embodiment, the reset arm  132  is a piece of curved plastic that bends resiliently during use.  
         [0067]    The actuator arm  134  has a neck  156  extending outward from the knuckle  130  and a head  158  joined to the neck  156 . Adjoining the head  158  are a pair of contacts  160  of a synchronization switch  162 . When the drive hub  128  pivots during discharge and the shutter  14  opens, the head  158  moves against the contacts  160  and presses the contacts  160  together. This provides a signal to a flash unit  164  that then fires a strobe tube (not separately illustrated). Suitable flash units for this purpose are well-known to those of skill in the art. The return of the shutter  14  to the closed position under the impetus of the return spring  112  moves of the head  158  of the actuator arm  134  away from the contacts  160 , reopening the sychronization switch  162 .  
         [0068]    As the shutter  14  opens during picture taking, a twisting force is applied to the shaft  116 . Flexure of of the shaft  116  as a result of this twisting force, can result in a lag in the opening of the shutter  14 . This is particularly problematic if the flexure and lag show large changes when the temperature of the camera changes during ordinary use, since the relative timing of shutter  14  opening and the closing of the sychronization switch also changes. For this reason, it is preferred that the shaft  116  does not flex during picture taking under ordinary environmental temperatures of 0 degrees to 100 degrees F. (For this purpose, a shaft  116  is considered to not flex if flexure of the shaft  116  during discharge is less than the clearance between the shutter  14  and the shaft  116 .) In a particular embodiment, the shaft  116  is made of stainless steel or another material of the same stiffness. Soft steel and other soft metals are not preferred, since those materials have a risk of deforming during use.  
         [0069]    In the embodiments just described, the shutter  14  slides on the shaft  116  and pivots with the shaft  116 . An advantage of this embodiment is that the position of the shaft  116  relative to the frame  20  does not change when the traveler  32  is moved. Due to this, the pivot axis  110  of the shutter  14  has a fixed relationship to the frame  20 . As a result, inaccuracies in the movement of the traveler  32  relative to the optical axis  16  are not transferred to the pivot axis  110  of the shutter  14 .  
         [0070]    Referring now to FIG. 13, in another embodiment of the invention, the shutter  14   a  slides on the shaft  116 , but, in this case, the tang  108   a  is part of the shutter  14   a  rather than the drive hub  128   a  and the striker  106   a  of the shutter driver  66   a  is lengthened to accommodate the movement of the tang  108   a . The drive hub  128   a  does not move axially and the passage  140  can be simplified to match the shape of the keyway  126 . The drive hub  128   a  otherwise functions as earlier described. This approach has the advantages earlier mentioned that the position of the shaft  116  relative to the frame  20  does not change when the traveler  32  is moved and the shaft  116  can act as a guide for the traveler  32  during movement of traveler  32 . On the other hand, the striker  106   a  must be lengthened to reach the tang  108   a  and space is needed within the traveler  32  for movement of the striker  106   a . There is also a risk that the long striker  106   a  will bend during picture taking, resulting in lag problems similar to those earlier discussed. A solution to this problem is the use of a striker  106   a  that is resistant to bending. For example, the striker  106   a  shown in FIG. 11 can be modified by use of a stiffening member (not shown) such as a length of stainless steel strip.  
         [0071]    This last embodiment can be modified by making the passage in the slider of the shutter circular in cross-section (not illustrated). In that case, the tang is again part of the shutter rather than the drive hub, but the drive hub is otherwise like the drive hub of FIG. 1. This approach is not preferred, because the shutter blade is less constrained than in the embodiment of FIG. 1 and there is an increased risk of the shutter tilting and allowing light leakage.  
         [0072]    Referring now to FIG. 14, in another embodiment of the invention, the shutter  14   b  is fixed in position on the shaft  116   b  and does not move axially back and forth relative to shaft  116   b . The manner of attachment is not critical. The shutter  14   b  can be adhered in place or held by a fastener or, as illustrated in FIG. 11, press fit. In this case, as the traveler  32  is moved back and forth along the optical axis  16 , the shutter  14   b  and shaft  116   b  both move with the traveler  32 . The bushings  138  in the face of the frame  20  and the cross wall  44  of the traveler  32  support pivoting movement and axial movement of the shaft  116   b . The shaft  116   b  can be longer than those earlier described, to allow the shaft  116   b  to move with the traveler  32 , while still remaining in both bushings  138 . The drive hub  128  does not differ from the drive hub  128  described in relation to the embodiment of FIG. 1. This embodiment has the advantage, like the embodiment of FIG. 1, that the position of the tang  108  does not change when the traveler  32  is moved along the optical axis  16 . The on the other hand, the shaft  116   b  is not a fixed guide for the movement of the traveler  32  and space must be provided in the frame  20  and traveler  32  to accommodate the axial movement of the shaft  116   b . There may also be an increased risk of the shutter tilting.  
         [0073]    The drive hub  128  can be used with in a camera having a shutter that has a fixed position and does not extend and retract with a lens barrel. FIG. 16 shows a modification of the lens module  22  of FIGS.  1 - 10 , in which the traveler and carrier are replaced by a first and second lens supports  168 , 170 , respectively. The twist ring is eliminated. An end cap  172  fits over the first and second lens supports  168 , 170  and is hooked onto the mount  27 . The first and second lens supports  168 , 170  are fixed in place, relative to the mount and each other, by friction fit or adhesive or fasteners or the like. The shutter mechanism is as in the embodiment of FIG. 1, but the shaft  116  is shortened and the shutter  14  is not free to move along the shaft  116 .  
         [0074]    [0074]FIGS. 15 and 19 illustrate another embodiment, in which a one-piece shutter-shaft  174  replaces the shutter and the shaft. The shutter-shaft  174  is biased by a spring  112  and has an attachment point  118 , a blocking portion  120 , and a neck  122  as in the earlier discussed shutter. The shaft  180  is a rearwardly extending protrusion formed with the neck  122  and blocking portion  120 . For example, the shutter-shaft can be a stamped metal part. The shutter-shaft  174  is used in a modification of the lens module of FIG. 16. The drive hub  128  rides on a post of the frame  20 , but is otherwise like the drive hub  128  of FIG. 1. The module is foreshortened and the second lens support  170  is aligned with the drive hub  128 .  
         [0075]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. Feature of the invention can be modified, for example, in accordance with the disclosures of one or more of the patent applications earlier incorporated by reference herein.