Exposure control mechanism

Claim 2

In an exposure control mechanism of a variety including at least one exposure mechanism blade movable between a terminal position blocking the passage of light through an exposure aperture and positions unblocking the passage of light through said aperture, said blade being connected with and drivably moved between said positions by a reciprocably movable drive assembly, said drive assembly being movable in one direction in conjunction with the selective energization of a tractive electromagnetic device having a movable actuating element the improvement comprising: means defining a first winding surface fixed to and movable with said drive assembly; drum means defining a rotatable second winding surface; belt means connected to and windable between said first and second winding surfaces; first spring means for biasing said drive assembly to move in said one direction; means connecting said tractive electromagnetic device actuating element and said drum means for rotating said second winding surface in a direction unwinding said belt means when said actuating element is moved in response to a said energization of said tractive electromagnetic device; and second spring means connected with said drum means for biasing said second winding surface to rotate in a direction winding said belt means thereupon.

Claim 3

The mechanism of claim 1 in which said first and second spring means are present as substantially flat rate springs.

Claim 4

The mechanism of claim 1 in which said second spring means is selected having force values for said bias which are greater than the force values of the said bias of said first spring means.

Claim 5

The mechanism of claiM 3 in which said second spring means is operative to rotate said drum means in a direction winding said belt means about said second winding surface and unwinding said belt means from said first winding surface when said tractive electromagnetic device is de-energized from an energized state.

Claim 6

The mechanism of claim 1 in which said connecting means includes a second belt means connected between said actuating element and said drive means and configured and arranged for selective winding about said second winding surface.

Claim 7

The mechanism of claim 1 including bracket means for supporting said reciprocably movable drive assembly for rotation about a given axis, said bracket means being configured for supporting said drum means for rotation about another axis parallel to said given axis.

Claim 8

The mechanism of claim 6 in which said bracket means and said drum means are mutually configured to limit the extent of rotation of said second winding surface.

Claim 9

The mechanism of claim 6 in which said second spring means is helically configured and spirally wound about said other axis.

Claim 10

The mechanism of claim 8 in which said second spring means is configured having a grounded end and movable end, and said movable end is connected to rotate said drum means second winding surface.

Claim 11

The mechanism of claim 1 in which: said belt means is connected to define a finite length thereof between said first and second winding surfaces; and including adjusting means for selectively varying the windable extent of said belt means so as to provide for the calibration of the extent of said movement of said drive assembly and said actuating element.

Claim 12

The mechanism of claim 1 including: bracket means for supporting said reciprocally movable drive assembly for rotation about a given axis; and wherein said first spring means is configured helically and spirally wound about said axis.

Claim 13

The mechanism of claim 11 in which said first winding surface is formed integrally with said reciprocally movable drive assembly and is present as the surface of a righr cylinder the axis of which coincides with said given axis.

Claim 14

An exposure control mechanism for photographic apparatus comprising: valve means movable between a terminal position blocking the passage of light along an optical path and open positions unblocking said light passage; reciprocating drive means connected with said valve means and movable in one direction to drive said valve means toward said terminal position and in a reverse direction to drive said valve means toward said open positions; first spring means for urging said reciprocating drive means to move in said one direction; means defining a first winding surface fixed to and movable with said reciprocating drive means; drum means defining a rotatable second winding surface; belt means connected to each and windable between said first and second winding surfaces; second spring means connected with said drum means for biasing said second winding surface to rotate in a direction winding said belt means thereupon, said bias being assertable through said belt means and said first winding surface to bias said reciprocating drive means for movement in said reverse direction; actuator means including an element reciprocally movable between retracted and extended positions respectively during drive and relaxed modes; and means connecting said actuator means element and said drum means for rotating said drum means second winding surface in a direction unwinding said belt means during said drive mode and for effecting said biased rotation winding said belt means during said relaxed mode.

Claim 15

An exposure control mechanism for photographic apparatus comprising: valve means movable between a terminal position blocking the passage of light along an optical path and open positions unblocking said light passage; reciprocating drive means connected with said valve means and movable in one direction to drive said valve means toward said terminal position and in a reverse direction to drive said valve means toward said open positions; first spring means for urging said reciprocating drive means to move in said one direction; means defining a first winding surface fixed to and movable with said reciprocating drive means; drum means defining a rotatable second winding surface; belt means connected to each and windable between said first and second winding surfaces; second spring means connected with said drum means for biasing said second winding surface to rotate in a direction winding said belt means thereupon, said bias being assertable through said belt means and said first winding surface to bias said reciprocating drive means for movement in said reverse direction; actuator means including an element reciprocally movable between retracted and extended positions respectively during drive and relaxed modes; and means connecting said actuator means element and said drum means for rotating said drum means second winding surface in a direction unwinding said belt means during said drive mode and for effecting said biased rotation winding said belt means during said relaxed mode.

Claim 16

The mechanism of claim 13 in which said first and second spring means are present as substantially flat rate springs.

Claim 17

The mechanism of claim 13 in which said second spring means is selected having force values for said bias which are greater than force values generated from said first spring means.

Claim 18

THe mechanism of claim 13 in which said second spring means is operative to rotate said drum means in a direction winding said belt means about said second winding surface and unwinding said belt means from said first winding surface during said relaxed mode.

Claim 19

The mechanism of claim 13 in which said connecting means includes second belt means connected between said actuator means element and said reciprocating drive means and configured and arranged for selective winding about said second winding surface.

Claim 20

The mechanism of claim 17 in which said actuator means is present as a solenoid having an excitation winding and said element thereof is present as a plunger retractable thereinto when said excitation winding is energized to establish said drive mode.