Abstract:
A camera having a manually operated zoom lens system, in which the magnification of the lens system is adjusted by manual rotation of a part of the lens systems. The camera includes a lens system having at least first and second optical elements, the first optical element being movable relative to the second optical element, a mechanism for moving the first optical element relative to the second optical element, and a rotatable element for operating the mechanism to change the magnification of the lens system. The camera further includes a view finder with adjustable magnification for providing a view representative of the image captured by the lens systems. The view finder includes first and second optical elements, the first element being moveable relative to the second element to change the magnification of the view finder and a mechanism for moving the first optical element relative to the second element.

Description:
FIELD OF THE INVENTION 
     This invention relates to cameras, and in particular to cameras with manually operated zoom lenses. 
     BACKGROUND OF THE INVENTION 
     Zoom lenses have been available for expensive, manually operated cameras for some time. These lenses are typically operated by sliding an element axially along the barrel of the lens to change the relative positions of the optical elements to increase and decrease the magnification. More recently, zoom lenses have been incorporated into less expensive automatic cameras that automatically change the relative positions of the optical elements to increase and decrease the magnification. However, zoom mechanisms have generally been too complicated and expensive to incorporate into inexpensive cameras. Moreover, in a compact, inexpensive camera, conventional zoom mechanisms did not provide adequate or accurate adjustment. Another difficulty in incorporating a zoom mechanism in an inexpensive camera is that such cameras typically have view finders, and it is difficult to inexpensively alter the view through the view finder to accurately reflect the image captured by the lens system. 
     SUMMARY OF THE INVENTION 
     The camera of the present invention includes a compact, inexpensive, manually operated zoom lens system. The magnification of the lens system is adjusted by manual rotation of a part of the lens systems. More specifically, the lens system has at least first and second optical elements, the first optical element being movable relative to the second optical element. The lens system also includes a mechanism for moving the first optical element relative to the second optical element, and a rotatable element for operating the mechanism to change the magnification of the lens system. Thus, manual rotation of the rotatable element changes the magnification of the lens system, so that magnification of the image can be quickly and accurately adjusted. The lens system also includes an inexpensive and simplified shutter mechanism and flash actuator. 
     In accordance with the preferred embodiment of this invention, the camera also includes a view finder which displays an image generally representative of the image captured by the lens system. This view finder is preferably automatically adjusted with the change in the magnification of the zoom lens system caused by rotation of the rotatable element. In the preferred embodiment, the view finder comprises first and second optical elements, the first element being moveable relative to the second element to change the magnification of the view finder. The view finder also comprises a mechanism for moving the first optical element relative to the second optical element. This mechanism is preferably connected to the lens system so that as the magnification of the lens system changes, the magnification of the view finder changes accordingly. In the preferred embodiment, the optical elements of the lens system and the optical elements of the view finder are constructed and arranged so that as the elements of the lens system move in one direction, the elements of the view finder move in the opposite direction to maintain the view through the view finder generally in accordance with the image captured by the lens system. Thus optical elements are selected so that as the first and second optical elements of the lens system move toward each other, the first and second optical elements of the view finder move away from each other, and vice versa. 
     Thus the camera of the present invention provides an inexpensive camera with a zoom lens that is simple and easy to use. The user can easily and accurately adjust the magnification of the lens system to change the image captured by the lens system. Moreover in the preferred embodiment, the image viewed through the viewfinder automatically changes with changes in the magnification in the lens system so that the view finder accurately reflects the image captured by the lens system, in a non-single lens reflex camera. 
     These and other features and advantages will be in part apparent, and in part pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a camera with a manually adjustable zoom lens in accordance with the principles of the present invention, shown adjusted to minimum magnification; 
     FIG. 2 is a perspective view of the camera, shown adjusted to the maximum magnification; 
     FIG. 3 is an exploded view of the parts comprising the lens and view finder systems of the camera; 
     FIG. 4 is a right side elevation view of the lens system providing the adjustable magnification, adjusted to the minimum magnification (corresponding to FIG.  1 ); 
     FIG. 5 is a right side elevation view of the lens system, adjusted to provide the maximum magnification (corresponding to FIG.  2 ); 
     FIG. 6 is a left side elevation view of the lens system and view finder system providing the adjustable magnification of the captured image and the viewed image, adjusted to the minimum magnification (corresponding to FIGS.  1  and  4 ); 
     FIG. 7 is a left side elevation view of the lens system and view finder system, adjusted to the maximum magnification (corresponding to FIGS.  2  and  5 ); 
     FIG. 8 is an end view of the camera lens covering the photo aperture; and 
     FIG. 9 is an end view of the shutter blade and flash actuator. 
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The manually operated zoom lens camera  10  of the invention is shown in FIGS. 1 and 2. For illustrative purposes the camera  10  that includes the inventive features of the invention is described as a conventional film camera, however the novel zoom lens system, view finder lens system and shutter mechanism and flash actuator of the invention that are employed in the camera to be described could be used in various different types of cameras including filmless digital cameras. 
     In the example of the camera shown in FIGS. 1 and 2, the camera  10  includes a camera body comprised of a front section  12  and a rear section  14  that enclose the internal components of the camera. In the preferred embodiment of the camera a majority of its component parts are constructed of plastic to reduce manufacturing costs. However, other materials may also be employed. The front section  12  and rear section  14  of the camera are secured together and together define a front surface  16 , a rear surface  18 , opposite left  20  and right  22  side surfaces and opposite top  24  and bottom  26  surfaces. The camera has an actuator button  28  on its top surface, a flash port  30  on its front surface, a view finder port  32  on its front surface and a zoom lens system  34  projecting from its front surface. The internal component parts of the camera that are not important to understanding the subject matter of the invention, for example the photo chamber and the film advancement system, are conventional and will not be described in detail. 
     FIG. 3 shows an exploded view of the component parts of the zoom lens system  34  of the invention. The zoom lens system  34  includes an annular camera body connector  38  that is secured in the interior of the camera body  10  around the photo chamber (not shown) of the camera. The term “photo chamber” as used herein is the enclosed chamber in the interior of the camera body through which film passes and is exposed to light on operation of the camera shutter to produce photographs. An annular base  40  of the lens system is secured to the body connector  38 . The base  40  has a recessed circular shoulder  42  in a forwardly facing surface of the base. 
     A zoom lens barrel  44  is mounted on the base  40  for rotational movement relative thereto. The zoom lens barrel  44  is cylindrical and has an annular ridge  46  that extends around a majority of the exterior of the barrel toward its rearward end. Adjacent the annular ridge  46  is a first curved slot  48  formed through the zoom lens barrel. The first slot  48  extends one quarter of the way around the zoom lens barrel  44  and curves in an axial direction as it extends around the barrel. A second curved slot  50  is also formed through the barrel  44 . The second curved slot  50  is positioned more toward the forward end of the zoom lens barrel  44 . The second slot  50  also extends one quarter of the way around the barrel and tapers axially slightly as it extends around the barrel. As best seen in FIGS. 4 and 6, the extent to which the first and second slots  48 ,  50  extend around the zoom lens barrel  44  is the same. 
     A ring cover  52  secures the zoom lens barrel  44  to the base  40 . The zoom lens barrel  44  is inserted into the base  40  with the annular ridge  46  of the barrel received on the recessed circular shoulder  42  of the base. The ring cover  52  is then passed over the barrel  44  and is secured to the base  40  covering over the annular ridge  46  of the barrel. The ring cover  52  has four tabs  54  that align with screw holes  56  on the base and is secured to the base by threaded fasteners (not shown) passed through holes of the tabs  54  and into the screw holes  56  of the base. In this manner, the zoom lens barrel  44  is mounted to the base  40  for rotational movement of the barrel relative to the base. In the preferred embodiment of the invention stops (not shown) are provided in the base  40  to limit the extent of rotation of the zoom barrel lens  44  to one-quarter of a turn. Also in the preferred embodiment a flexible, annular grip  58  is mounted on the exterior of the zoom lens barrel  44  to provide a gripping surface for turning the barrel one-quarter turn in either direction. The annular grip  58  is shown in FIGS. 1 and 2. 
     A zoom lens tube  62  passes through the interior of the zoom lens barrel  44 . The zoom lens tube has a shutter surface  64  that extends across the interior of the tube and divides the tube interior into two sections. Behind the shutter surface  64  the zoom lens tube  62  is not cylindrical but has opposite flat surfaces  66 , only one of which can be seen in FIG.  3 . Opposite arcuate surfaces  68  of the zoom lens tube extend between the opposite flat surfaces  66 . The arcuate surfaces  68  and flat surfaces  66  of the tube are dimensioned to fit over complementary shaped surfaces of the photo chamber (not shown) of the camera to mount the zoom lens tube  62  to the photo chamber and the camera. This method of mounting the zoom lens tube  62  to the photo chamber enables the tube to slide axially rearwardly and forwardly with the opposite flat surfaces  66  of the tube preventing rotation of the tube relative to the camera. 
     A tube pin  70  is secured to the exterior surface of the zoom lens tube  62  and is positioned in the first curved slot  48  of the zoom lens barrel  44 . Thus, on rotation of the zoom lens barrel  44  in opposite directions, the tube pin  70  passes through the first curved slot  48  of the barrel causing the zoom lens tube  62  to be moved forwardly and rearwardly relative to the camera body  10  due to the curvature of the first curved slot  48 . The curvature of the first curved slot  48  will cause the zoom lens tube  62  to be moved forwardly from the zoom lens barrel  44  in response to the barrel being rotated in a counter clockwise direction as viewed in FIGS. 1 through 3. The curvature of the first slot  48  will also cause the zoom lens tube  62  to be moved rearwardly and retracted back into the zoom lens barrel  44  in response to the barrel being rotated in a clockwise direction as viewed in FIGS. 1 through 3. FIG. 1 shows the zoom lens tube  62  retracted into the zoom lens barrel  44  and FIG. 2 shows the zoom lens tube  62  extended from the zoom lens barrel  44 . 
     The shutter surface  64  that extends across the interior of the zoom lens tube  62  can be seen in FIGS. 8 and 9 which are views into the forward end of the zoom lens tube  62 . FIG. 8 shows a first or proximal photo lens frame  72  and lens  74  mounted on the shutter surface  64 . The photo lens frame  72  positions the first or proximal photo lens  74  over the photo aperture  76  that is shown in dashed lines in FIG.  9 . FIG. 9 shows the photo lens frame  72  and photo lens  74  removed from the shutter surface  64  to provide a better view of the shutter  78  of the camera. 
     The shutter  78  is mounted on the shutter surface  64  for movement between a closed position shown in solid lines in FIG.  9  and an open position shown in dashed lines in FIG.  9 . The shutter  78  includes a blade  80  that is dimensioned to cover over the photo aperture  76  through the shutter surface  64  when the shutter is in the closed position. The shutter has an oblong slot  82  that is mounted over a post  84  on the shutter surface  64 , thereby mounting the shutter for pivoting movement between its opened and closed positions. An actuator arm  86  of the shutter projects over a slot  88  through the shutter surface  64 . When the actuator button  28  of the camera is depressed, an actuator mechanism (not shown) moves through the shutter surface slot  88  from the left to the right as shown in FIG.  9  and engages the actuator arm  86  of the shutter. As the mechanism moves to the right its engagement with the actuator arm  86  causes the shutter to pivot about the pivot post  84  moving the blade  80  away from and eventually displacing the blade from the photo aperture  76 , thus taking a photograph. The actuator mechanism eventually moves past the shutter actuator arm  86  and a spring  90  connected between a post  92  on the shutter and a post  94  on the shutter surface  64  pulls the shutter back to its closed position. An arcuate wall  96  on the shutter surface  64  stops the movement of the shutter  78  due to the bias of the spring  90  and positions the shutter blade  80  over the photo aperture  76 . 
     A flash switch  98  is also mounted on the shutter surface  64  adjacent the shutter  78 . The flash switch  98  has a pair of electrical contacts  100  that project from the switch. The electrical contacts  100  are flexible and are positioned a slight distance away from each other. However, when the shutter  78  is moved toward its opened position the shutter blade  80  comes into contact with the electrical contacts  100  causing them to contact each other. This contact between the electrical contacts  100  of the flash switch  98  closes the switch and activates the flash mechanism of the camera. This closing of the flash switch  98  occurs just as the shutter  78  is coming to its opened position where it is completely displaced from the photo aperture  76  as depicted by the dashed line representation of the shutter shown in FIG.  9 . The simplified shutter system and the manner in which it activates the flash switch  98  of the camera reduces the manufacturing costs of the camera. 
     Positioned on the interior surface of the zoom lens tube  62  forwardly of the shutter surface  64  are pairs of axially extending ribs  102  that define axial grooves therebetween. Also positioned in front of the shutter surface  64  and circumferentially positioned between the two pairs of axial ribs  102  is a straight slot  104  that extends axially along the zoom lens tube  62  for a short axial distance. 
     A photo lens frame  106  mounting a second or distal photo lens  108  is received in the zoom lens tube  62 . The photo lens frame  106  has opposite flanges  110  (only one of which can be seen in FIG. 3) that are received in the grooves between the axial rib  102  on the interior of the zoom lens tube  62 . This mounts the photo lens frame  106  for sliding movement in the interior of the zoom lens tube  62 . A photo lens pin  112  is secured to the photo lens frame  106  and passes through the straight slot  104  of the zoom lens tube  62  and into the second tapered slot  50  of the zoom lens barrel  44 . Thus, on rotation of the zoom lens barrel  44  in opposite directions, the photo lens pin  112  travels through the second slot  50  of the zoom lens barrel and moves the photo lens frame  106  forwardly and rearwardly relative to the zoom lens tube  62 . The straight slot  102  in the zoom lens tube  62  holds the photo lens frame  110  against rotation as it is moved forwardly and rearwardly by rotation of the zoom lens barrel  44 . In this manner, rotation of the zoom lens barrel  44  in opposite directions results in axial forward and rearward movement of the first photo lens  74  and the second photo lens  108  relative to the photo chamber (not shown) of the camera and also moves the first photo lens  74  and the second photo lens  108  forwardly and rearwardly relative to each other to produce the zooming in and zooming out function of the zoom lens system of the invention. 
     A circular zoom lens cover  114  with a zoom window  116  is fit over the forward end of the lens tube  62  to seal closed the lens tube and protect its interior components. 
     The view finder lens system of the invention is mounted above the base  40  of the zoom lens system just behind the view finder port  32  of the camera. The view finder mechanism is shown in FIGS. 3,  5  and  7 . The view finder lens system includes a stationary lens housing with a bottom surface  118  of the housing secured to the top of the zoom lens system base  40 . The housing includes a pair of stationary viewing lenses  120  that are secured in the housing in a spaced relationship and are covered over by a top  122  of the view finder housing. The housing top  122  has a side guide arm  124  and a pair of top guide arms  126  that project axially forward from the housing top. A guide wall  128  having a guide slot (not shown) in its top surface is positioned at one side of the view finder housing. 
     Positioned in front of the view finder housing is a viewing lens frame  130  with a moveable viewing lens  132  mounted in the frame. An arm  134  projects rearwardly from the viewing lens frame  130  and a pair of pins  136  project downwardly from the arm  132  into the groove in the top surface of the guide wall  128 . Thus, the frame arm  34  is mounted for axially forward and rearward movement between the guide wall  128  and the side guide arm  124  of the housing top wall. The axial movement of the frame arm  134  also causes the viewing lens frame  130  and the moveable viewing lens  132  it supports to move forwardly and rearwardly relative to the pair of stationary viewing lenses  120  in the view finder housing. 
     The viewing lens frame  130  is operatively connected to the zoom lens barrel  44  and, more specifically the zoom lens tube  62  by a linkage. The linkage includes a tooth rack  138  on the frame arm  134 . It also includes an arm  140  having a pivot pin  142  that projects rearwardly from the zoom lens tube  62  as shown in FIGS. 5 and 7. Connecting the tube arm  140  to the frame arm  132  is a link  144  having a length with an opening  146  at one end and a gear segment  148  at its opposite end. A pivot shaft  150  projects from the link intermediate its opposite ends. A grooved plate  152  is secured to the bottom  118  of the view finder housing with the pivot shaft  150  of the link positioned between a groove in the plate  152  and the housing bottom  118 , thereby mounting the link  144  for pivoting movement at the side of the view finder housing. The link opening  146  is received over the pin  142  of the tube arm  140  and the link gear segment  148  meshes with the tooth rack  138  of the moveable lens frame arm  134 . Thus, on movement of the zoom lens tube  62  between its retracted position shown in FIG. 5 to its forward position shown in FIG. 7, the link  144  is caused to pivot counterclockwise as shown in FIGS. 5 and 7. This causes the gear segment  148  of the link to mesh with the tooth rack  138  of the moveable viewing lens frame arm  134  which in turn causes the moveable viewing lens  132  to move rearwardly toward the stationary lenses of the view finder. Opposite movement of the zoom lens tube  62  from its extended position shown in FIG. 7 to its retracted position shown in FIG. 5 causes the link  144  to pivot in a clockwise direction which in turn causes its gear segment  148  to move the tooth rack  138  and the moveable viewing lens  132  supported on the viewing lens frame  130  forwardly relative to the stationary lenses  120  of the view finder. In this manner, the zoom lens system and the view finder lens system of the invention work together to give the user of the camera an adjusted magnified view through the stationary lenses  120 , the moveable viewing lens  132  and an exterior viewing lens  154  of the view finder that is representative of the zoomed lens image to be photographed on adjustment of the zoom lens system of the invention. Because the zoom lens system and the view finder lens system are interconnected by a simple, mechanical connection of only a few component parts, the cost of construction is reduced. 
     Although the novel features of the invention have been described above by referring to a specific embodiment of the invention, it should be understood that component parts of the invention could be changed slightly, for example employing a gear meshing with two tooth racks on the zoom lens tube  62  and the moveable viewing lens frame  130  in lieu of the link  144  described, without departing from the intent of the invention. 
     While the present invention has been described by reference to specific embodiments, it should be understood that modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the following claims.