Abstract:
A shutter mechanism comprising a shutter that is operated to allow the passage of light, and a self-timer with a shaped memory alloy control that can be deformed and that when subjected to electrical current heats to recover from being deformed and after some delay during recovery initiates operation of the shutter, is characterized in that a manually set timer member is connected to the shaped memory alloy control and is supported to be manually moved to deform the shaped memory alloy control to set the self-timer and for the shaped memory alloy control to reverse-move the timer member during recovery of the shaped memory alloy control.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to the field of photography, and in particular to cameras. More specifically, the invention relates to a shutter mechanism including a self-timer with a shaped memory alloy control. 
     BACKGROUND OF THE INVENTION 
     A shutter controls the time during which light is allowed to reach the sensitized material in a camera. The shutter consists of some means of normally covering the taking lens, the aperture stop, or the film light-tight, uncovering it for a brief time and then covering it up again. 
     A self-timer is a delayed action release for the shutter. The self-timer, when set, delays operation of the shutter for a certain time. This, for example, enables the photographer to place himself in front of the camera to be photographed. 
     Prior art U.S. Pat. No. 5,459,544 issued Oct. 17, 1995 proposes that the self-timer have a shaped memory alloy control for delaying operation of the shutter. The shaped memory alloy control is a metallic fine wire that is mechanically deformed (stretched) lengthwise via a spring and that when subjected to electrical current heats (because of its electrical resistance) to recover (shrink) lengthwise from being deformed and after some delay during recovery initiates operation of a shutter. When the electrical current is discontinued, the wire cools which allows the spring to again deform (stretch) the wire. 
     SUMMARY OF THE INVENTION 
     A shutter mechanism comprising a shutter that is operated to allow the passage of light, and a self-timer with a shaped memory alloy control that can be deformed and that when subjected to electrical current heats to recover from being deformed and after some delay during recovery initiates operation of the shutter, is characterized in that: 
     a manually set timer member is connected to the shaped memory alloy control and is supported to be manually moved to deform the shaped memory alloy control to set the self-timer and for the shaped memory alloy control to reverse-move the timer member during recovery of the shaped memory alloy control. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a shutter mechanism according to a preferred embodiment of the invention; 
     FIG. 2 is a rear perspective view of the shutter mechanism as shown in FIG. 1; and 
     FIGS. 3-10 are alternate front and rear perspective views of the shutter mechanism, depicting its operation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is disclosed as being embodied preferably in shutter mechanism including a self-timer, for a camera. Because the features of such a shutter mechanism 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. 
     Referring now to the drawings, FIGS. 1 and 2 show a shutter mechanism  10  including a shutter blade  12  that has an impact receiving tip  14  and is pivotally supported via a fixed pin  16  within a slot  18  in the shutter blade, and a shutter actuator  20  that has a striker  22  and is pivotally supported via a fixed pin  24  within an opening  26  in the shutter actuator. The fixed pins  16  and  24  project from a camera main body part  28 . An actuating spring  30  pivots the shutter actuator  20  counter-clockwise in FIG.  9  and clockwise in FIG. 10 to swing its striker  22  against the tip  14  of the shutter blade  12  to pivot the shutter blade clockwise in FIG.  9  and counter-clockwise in FIG. 10 about the fixed pin  16 . The shutter blade  12  then uncovers an aperture stop (not shown). As soon as the striker  22  swings beyond the tip  14 , a return spring (not shown) pivots the shutter blade  12  counter-clockwise in FIG.  9  and clockwise in FIG. 10, for the shutter blade to again cover the aperture stop. 
     A latch  32  is pivotally supported via a fixed pin  34  within an opening  36  in the latch. The fixed pin  34  projects from the camera main body part  28 . A return spring  38  urges the latch  32  clockwise in FIG.  1  and counter-clockwise in FIG. 2 swing one end  40  of the latch into engagement with the shutter actuator  20  at a notch  42  in the shutter actuator, to prevent the shutter actuator from being pivoted counter-clockwise in FIG.  1  and clockwise in FIG. 2 to swing its striker  22  against the tip  14  of the shutter blade  12  to pivot the shutter blade to uncover the aperture stop. 
     A manually depressible release member  44  is supported for translation via fixed pins  46  and  48  within respective aligned slots  50  and  52  in the release member. The fixed pins  46  and  48  project from the camera main body part  28 . The release member  44  has an integral top push button  54  that protrudes from a top opening in a camera housing (not shown) to permit one to manually depress the release member, and a release pin  56  that pushes against another end  58  of the latch  32  to pivot the latch counter-clockwise in FIG.  5  and clockwise in FIG. 6 to remove the end  40  of the latch from the notch  42  in the shutter actuator  20  when the release member is manually depressed. 
     A timer member  60  is supported for translation via fixed pins  62  and  64  within respective aligned slots  66  and  68  in the camera main body part  28 . The fixed pins  62  and  64  project from the timer member  60 . A shaped memory alloy (SMA) control  70 , preferably in the form of a metallic fine wire similar to one disclosed in prior art U.S. Pat. No. 5,459,546 (which is incorporated in this patent), has one end secured to the timer member  60  and another end secured to the camera main body part  28 . As described in the incorporated patent, the SMA wire  70  can be mechanically deformed (stretched) lengthwise and when subjected to electrical current heats (because of its electrical resistance) to recover (shrink) lengthwise from being deformed. Since the SMA wire  70  is not resilient, it can not recover its original size and shape without heating. The timer member  60  has an integral side guide pin  72  that projects into a reverse-c-shaped open channel  74  in the release member  44 , and an integral side push button  76  that protrudes from a side slot  78  in the camera housing and is aligned with the fixed pin  62  in the slot  66 . See FIGS. 1 and 2. The push button  76  permits one to manually translate the timer member  60  to the left in FIG.  3  and to the right in FIG. 4, which deforms (stretches) the SMA wire  70  lengthwise and translates the guide pin  72  from one horizontal segment  80  of the reverse-c-shaped channel  74  in the release member  44  to against an upstanding integral resilient finger  82  of the release member that projects within an opening  84  in the release member. The height of the slot  68  is slightly greater than the height of the slot  66  to permit the timer member  60  to be pivoted slightly clockwise in FIG.  7  and counter-clockwise in FIG. 8 at the fixed pin  62  in the slot  66 . 
     A blocking member  86  is supported for translation via fixed pins  88  and  90  within respective aligned slots  92  and  94  in the blocking member. The fixed pins  88  and  90  project from the camera main body part  28 . When the timer member  60  is manually translated to the to the left in FIG.  3  and to the right in FIG. 4, a raised motion-inducing or cam portion  96  of the timer member raises the blocking member in FIGS. 3 and 4 to position and hold the blocking member slightly spaced from the striker  22  of the shutter actuator  20  to prevent the striker from swinging against the tip  14  of the shutter blade  12 . A return spring  98  urges the blocking member  86  continuously against the timer member  60  as shown in FIGS. 1 and 2. 
     Operation 
     The timer member  60 , the SMA wire  70 , and the blocking member  86  function, in effect, as a settable self-timer  100 . 
     To take a picture without using the self-timer  100 , one manually depresses the release member  44  downward in FIGS. 1 and 2 against the continuous upward urging of a return spring (not shown). This causes the release pin  56  on the release member  44  to push against the end  58  of the latch  32  and pivot the latch counter-clockwise in FIG.  5  and clockwise in FIG. 6 to remove the end  40  of the latch from the notch  42  in the shutter actuator  20 . The actuating spring  30  then pivots the shutter actuator  20  counter-clockwise in FIG.  9  and clockwise in FIG. 10 to swing its striker  22  against the tip  14  of the shutter blade  12  to pivot the shutter blade clockwise in FIG.  9  and counter-clockwise in FIG. 10 about the fixed pin  16  on the main body part  28 . The shutter blade  12  then uncovers the aperture stop. As soon as the striker  22  swings beyond the tip  14 , the return spring pivots the shutter blade  12  counter-clockwise in FIG.  9  and clockwise in FIG. 10, for the shutter blade to again cover the aperture stop. 
     When the release member  44  is manually depressed downward in FIGS. 1 and 2, without using the self-timer  100 , a vertical segment  102  of the reverse-c-shaped channel  74  in the release member is lowered along the guide pin  72  on the timer member  60 . The timer member  60  remains stationary. 
     To take a picture using the self-timer  10 , one manually translates the timer member  60  to the left in FIG.  3  and to the right in FIG. 4, which mechanically deforms (stretches) the SMA wire  70  lengthwise and translates the guide pin  72  on the timer member from the segment  80  of the reverse-c-shaped channel  74  in the release member  44  to against the resilient finger  82  of the release member  44  that projects within the opening  84  in the release member. The raised motion-inducing portion  96  of the timer member  60  raises the blocking member  86  in FIGS. 3 and 4 to position and hold the blocking member slightly spaced from the striker  22  of the shutter actuator  20  to prevent the striker from swinging against the tip  14  of the shutter blade  12 . 
     At this stage, the self-timer  100  is set. However, the timer-member  60  can be manually reverse-moved to the right in FIG.  3  and to the left in FIG. 4 to cancel setting the self-timer  100 . If the timer member  60  is reverse-moved, the SMA wire  70  becomes slack or droops, the guide pin  72  on the timer member  60  is translated from against the resilient finger  82  of the release member  44  and into the horizontal segment  80  of the reverse-c-shaped channel  74  in the release member, and the raised motion-inducing portion  96  of the timer member  60  is retracted from the blocking member  86 . The return spring  98  then lowers the blocking member  86  in FIGS. 3 and 4 out of the way of the striker  22  of the shutter actuator  20  and against the timer member  60 . 
     If one manually depresses the release member  44  downward in FIGS. 5 and 6 against the continuous upward urging of the return spring, when the self-timer  100  is set, the resilient finger  82  of the release member is lowered in FIGS. 5 and 6 and the guide pin  72  on the timer member  60  is captured (engaged) via the top end  104  of the resilient finger as shown in FIG.  5 . In addition, the release pin  56  on the release member  44  pushes against the end  58  of the latch  32  to pivot the latch counter-clockwise in FIG.  5  and clockwise in FIG. 6 to remove the end  40  of the latch from the notch  42  in the shutter actuator  20 . The actuating spring  30  then pivots the shutter actuator  20  slightly counter-clockwise in FIG.  5  and clockwise in FIG. 6 to move a stop portion  106  of the shutter actuator beneath the latch  32  to be able to hold the latch substantially in place when the return spring raises the release member  44 . The raised motion-inducing portion  96  of the timer member  60  continues to hold the blocking member  86  in position to prevent the striker  22  of the shutter actuator  20  from swinging against the tip  14  of the shutter blade  12 . 
     At this stage, the setting of the self-timer- 100  cannot be cancelled because the guide pin  72  on the timer member  60  is captured (engaged) via the top end  104  of the resilient finger  82  of the release member  44  as shown in FIG. 5 
     When one ceases to hold the release member  44  manually depressed downward, in FIGS. 7 and 8 the return spring begins to raise the release member upward. Initially, the release pin  56  on the release member  44  is removed from against the end  58  of the latch  32 , which allows the return spring  38  to pivot the latch slightly clockwise in FIG.  7  and counter-clockwise in FIG. 6 to against the stop portion  106  of the shutter actuator  20 , and the top end  104  of the resilient finger  82  of the release member pushes against the guide pin  72  on the timer member  60  to slightly pivot the timer member clockwise in FIG.  7  and counter-clockwise in FIG. 8 at the fixed pin  62  on the timer member, in the slot  66  in the main body part  28 . The timer member  60  then closes a biased-open switch  108  in a known electrical circuit (not shown) which includes the SMA wire  70 , to subject the SMA wire to electrical current that heats the SMA wire to cause it to begin to recover (shrink) lengthwise from being mechanically deformed (stretched). The raised motion-inducing portion  96  of the timer member  60  continues to hold the blocking member  86  in position to prevent the striker  22  of the shutter actuator  20  from swinging against the tip  14  of the shutter blade  12 . 
     When the SMA wire  70  recovers (shrinks) lengthwise as shown in FIGS. 9 and 10, it translates the timer member  60  to the right in FIG.  9  and to the left in FIG. 10, which causes the raised motion-inducing portion  96  of the timer member to be retracted from the blocking member  86 . The return spring  98  then lowers the blocking member  86  in FIGS. 9 and 10 out of the way of the striker  22  of the shutter actuator  20  and against the timer member  60 . The actuating spring  30  pivots the shutter actuator  20  counter-clockwise in FIG.  9  and clockwise in FIG. 10 to swing its striker  22  against the tip  14  of the shutter blade  12  to pivot the shutter blade clockwise in FIG.  9  and counter-clockwise in FIG. 10 about the fixed pin  16  on the main body part  28 . The shutter blade  12  then uncovers the aperture stop. As soon as the striker  22  swings beyond the tip  14 , the return spring pivots the shutter blade  12  counter-clockwise in FIG.  9  and clockwise in FIG. 10, for the shutter blade to again cover the aperture stop. 
     As the SMA wire  70  recovers (shrinks) lengthwise as shown in FIGS. 9 and 10 and translates the timer member  60  to the right in FIG.  9  and to the left in FIG. 10, the guide pin  72  on the timer member  60  is translated from the top end  104  of the resilient finger  82  of the release member  44  and into another horizontal segment  110  of the reverse-c-shaped channel  74  in the release member. When the guide pin  72  is translated from the horizontal segment  110  of the reverse-c-shaped channel  74  to the vertical segment  102  of the reverse-c-shaped channel as shown in FIG. 9, the return spring can further raise the release member  44  upward and the biased open switch  108  can slightly pivot the timer member  60  counterclockwise in FIG.  9  and clockwise in FIG. 10 at the fixed pin  62  on the timer member, in the slot  66  in the main body part. The biased-open switch  108  then opens to discontinue the flow of electrical current in the SMA wire  70 . The timer member  60  comes to rest as shown in FIG.  1 . And the return spring raises the release member  44  upward to return the guide pin  72  to the horizontal segment  80  of the reverse-c-shaped channel as shown in FIG.  1 . 
     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. 
     PARTS LIST 
       10 . shutter mechanism 
       12 . shutter blade 
       14 . impact receiving tip 
       16 . fixed pin 
       18 . slot 
       20 . shutter actuator 
       22 . striker 
       24 . fixed pin 
       26 . opening 
       28 . main body part 
       30 . actuating spring 
       32 . latch 
       34 . fixed pin 
       36 . opening 
       38 . return spring 
       40 . latch end 
       42 . notch 
       44 . release member 
       46 . fixed pin 
       48 . fixed pin 
       50 . slot 
       52 . slot 
       54 . push button 
       56 . release pin 
       58 . latch end 
       60 . timer member 
       62 . fixed pin 
       64 . fixed pin 
       66 . slot 
       68 . slot 
       70 . shaped memory alloy control 
       72 . guide pin 
       74 . reverse-c-shaped channel 
       76 . push button 
       78 . side slot 
       80 . horizontal segment 
       82 . resilient finger 
       84 . opening 
       86 . blocking member 
       88 . fixed pin 
       90 . fixed pin 
       92 . slot 
       94 . slot 
       96 . motion-inducing portion 
       98 . return spring 
       100 . self-timer 
       102 . vertical segment 
       104 . top end 
       106 . stop portion 
       108 . switch 
       110 . horizontal segment