Camera with lens disc drive system

• US 4,336,988 A
• Filed: 01/02/1981
• Issued: 06/29/1982
• Est. Priority Date: 01/02/1981
• Status: Expired due to Term

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Johnson, Bruce K.
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Perkey, William B.
• Application Number:
  US06/222,011
• Time in Patent Office: 543 Days
• Field of Search: 354/25, 354/25 A, 354/195, 354/197, 354/31 F, 354/226, 354/230, 354/247, 354/266-268, 354/25 P, 354/25 N, 352/140, 352/142, 355/56
• US Class Current: 396/74
• CPC Class Codes: G02B 7/40 using time delay of the reflected waves, e.g. of ultrasonic waves
• CPC Class Codes: G03B 9/42 with adjustable slot; with mechanism controlling relative movement of plates to form slot

Abstract

A camera having an automatic lens focusing system is provided with a torsion spring drive arrangement for rotatably driving a disc having a plurality of different focal length lens elements thereon in circumferentially spaced apart relation to sequentially present each of the lens elements at a focusing position. A combined shutter blade latch and lens disc actuator member is movable between latching and unlatching positions and additionally serves to releasably hold an acceleration arm of the torsion spring at an initial cocked position, to release the acceleration arm to effect disc rotation in response to movement of the member from the latching to the unlatching position, and thereafter to recock the acceleration arm when the member is moved back to the latching position.

Claims

1. A camera having means for defining a film plane, said camera comprising:

a plurality of discrete lens elements each having a different focal length;

means for holding said plurality of lens elements in circumferentially spaced apart relation with respect to each other for rotation about a center axis, rotation of said lens holding means from an initial position operating to sequentially move each of said lens elements into position to focus an image onto the camera film plane of a photographic subject located within a different corresponding camera-to-subject distance range;

a blade mechanism;

means for mounting said blade mechanism for displacement between one arrangement in which said blade mechanism blocks transmission of scene light to the film plane and another arrangement in which said blade mechanism unblocks transmission of scene light to the film plane;

actuable drive means for displacing said blade mechanism between its said one and another arrangements to define an exposure interval;

a torsion spring having an acceleration arm configured to be releasably held at cocked energy storing initial position and upon release to move to a terminal position, said acceleration arm operating during such movement from said initial to said terminal position to engage said lens holding means and effect rotation thereof to sequentially move each of said lens elements into focusing position; and

means for releasably latching said blade mechanism in its said scene light blocking arrangement and also for releasably holding said acceleration arm in said cocked initial position, said blade latching and acceleration arm holding means being movable from a blade mechanism latching position to a blade mechanism unlatching position to enable said drive means to displace said blade mechanism between said blocking and said unblocking arrangements, said movement from said latching to said unlatching position simultaneously operating to release said acceleration arm for movement from said initial cocked position to said terminal position to effect rotation of the lens holding means.

2. The camera of claim 1 wherein said blade latching and acceleration arm holding means also operates, in response to movement thereof from said unlatching position back to said latching position, to move said acceleration arm from said terminal position back to said initial cocked position.

3. The camera of claim 2 wherein said blade latching and acceleration arm holding means are embodied in a unitary latch and lens actuator member mounted for pivotal motion between said latching and unlatching position and said latch and lens actuator member includes a tab thereon for selectively engaging said acceleration arm to releasably hold it in said initial cocked position and to move said acceleration arm from said terminal position back to said initial cocked position.

4. The camera of claim 3 wherein said lens holding means includes a disc having an acceleration tab thereon configured to be engaged by said acceleration arm to impart rotary motion to said disc, said latch and actuator member is configured to pivot from said latching to unlatching position to move said acceleration arm engaging tab thereon in the same direction of movement of said acceleration arm from said initial position to said terminal position, and said camera further includes means for pivoting said latch and actuator member from said latching to said unlatching position at a rate such that the said acceleration arm engaging tab thereon moves ahead of acceleration arm at a faster rate than said acceleration arm can move under the inertial load of said disc to thereby release said acceleration arm and provide clearance for its movement from said initial position to said terminal position.

5. The camera of claim 4 wherein said latch and lens actuator member releasably holds said acceleration arm at said initial position with a portion thereof configured to engage said tab on said disc spaced from said disc tab when said disc is located in its said initial position to facilitate complete release of said acceleration arm by said blade latch and lens actuator member before said portion of said acceleration arm engages said disc tab.

6. The camera of claims 4 and 5 wherein said disc includes a center hub portion for receiving a disc pivot pin and said torsion spring includes a center coiled portion disposed around said hub.

7. The camera of claim 6 further including a second torsion spring coupled to said disc for imparting rotary movement thereto, in a direction opposite to the direction of movement imparted to said disc by said acceleration arm, for moving said disc back to its said initial position.

8. The camera of claim 3 further including a resiliently deformable energy absorbing stop engageable by said tab on said latch and lens actuator when located in its said unlatching position to facilitate stopping of said latch and lens actuator member thereat with minimum oscillation.