High-speed shutter

Claim 2

In a camera, a shutter mechanism comprising a shutter mounted in the camera for movement between two positions, a length of wire secured at one end to the camera and mechanically linked to the shutter at the other end for moving the shutter from one of its positions to its other position, said wire being of the type which when stretched is quiescent at its stretched length and has a memory for its prestretched length and is characterized by a martensitic critical temperature, shutter cocking means linked to said shutter for moving the shutter from its other position to its one position and for stretching said wire, said shutter cocking means including a second length of wire of the same kind of material as the first-recited wire and secured at one end to the camera and at its other end mechanically linked to the shutter said lengths of wire being oriented in opposition, and a current pulse generator connected to the second length of wire for producing a transient temperature rise in the second length of wire with a peak at least as high as its martensitic critical temperature and of sufficient persistence to return the latter to its prestretched length and to move the shutter to its one position and to stretch the first-recited wire.

Claim 3

In a camera, a shutter mechanism comprising two shutters each having an aperture, spaced pivots mounting the two shutters respectively so that their apertures are displaceable along arcuate paths along which the apertures can overlap, two lengths of wire for the shutters secured at one of their ends to the camera and at their other ends to the respective shutters, said wire being of the type which when stretched is quiescent at its stretched length and has a memory for its prestretched length and is characterized by a martensitic critical temperature, separate means for raising the temperature of each length of wire above its martensitic critical temperature, the shutter apertures being non overlapping when the two lengths of wire are unstretched, means for stretching both lengths of wire and for pivoting the shutters to cocked positions, the shutter apertures being non overlapping when the shutters are cocked, means for activating first one of said separate means and then the other of said separate means whereby the stretched lengths of wire are restored to unstretched lengths in succession and the respective shutters are pivoted in succession and during such pivotings the aperture of the second pivoted shutter passes across the aperture of the first pivoted shutter.

Claim 4

In a camera, a shutter mechanism comprising two shutters each having an aperture, spaced pivots mounting the two shutters respectively so that their apertures are displaceable along arcuate paths along which the apertures can overlap, two lengths of wire for the shutters secured at one of their ends to the camera and at their other ends to the respective shutters, said wire being of the type which when stretched is quiescent at its stretched length and has a memory for its prestretched length and is characterized by a martensitic critical temperature, separate means for raising the temperature of each length of wire above its martensitic critical temperature, the shutter apertures being non overlapping when the two lengths of wire are unstretched, means for stretching both lengths of wire and for pivoting the shutters to cocked positions, the shutter apertures being non overlapping when the shutters are cocked, means for activating first one of said separate means and then the other of said separate means whereby the stretched lengths of wire are restored to unstretched lengths in succession and the respective shutters are pivoted in succession and during such pivotings the aperture of the second pivoted shutter passes across the aperture of the first pivoted shutter.

Claim 5

In a camera, a shutter mechanism as defined in claim 2 wherein said separate means are pulse generators connected across the lengths of wires and said means for activating is a differential trigger means coupled to the pulse generators.

Claim 6

In a camera, a shutter mechanism as defined in claim 3 wherein said means for stretching both lengths of wire and for pivoting the shutters to cocked positions includes two additional lengths of wire of said type secured to said camera and mechanically linked to said shutters in opposition to the first recited lengths of wire and being stretched and unstretched when the first recited lengths of wire are unstretched and stretched respectively, said means for stretching further including a pulse generator connected across both the second recited lengths of wire for heating both the latter concurrently above the martensitic critical temperature.

Claim 7

In a camera, a shutter mechanism as defined in claim 3 wherein said means for stretching both lengths of wire and for pivoting the shutters to cocked positions includes electrically energizable motor means linked to both shutters and a pulse generator for energizing said electrically energizable motor means.