US 4,008,448 AGranted

Solenoid with selectively arrestible plunger movement

AssigneePolaroid Corporation

InventorJuerg Muggli

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Abstract

A solenoid comprising an excitation winding, a stationary armature, and a plunger disposed in cooperative arrangement such that a select partial energization of the winding operates to urge the plunger to displace laterally with respect to the winding and armature thereby stopping the plunger from further axial translation regardless of the plunger position and whereby full energization of the winding operates to urge the plunger to translate into the winding toward the armature.

Claims11

Dependent claims

Solenoid apparatus comprising:

an elongated excitation winding defining a longitudinal axis around which said excitation winding is disposed, along which said excitation winding extends, and with respect to which said excitation winding is radially spaced;
means for cooperating with said excitation winding, when said excitation winding is energized, for establishing a substantially low reluctance flux path for the electromagnetic field of said excitation winding, said flux path establishing means including a stationary armature positioned adjacent one end of said excitation winding and extending intermediate portions of said excitation winding disposed on opposite sides of said longitudinal axis to define a first surface positioned within said excitation winding intermediate said excitation winding and said axis and an elongated plunger disposed generally along said axis and having an end portion extending between radially disposed portions of said excitation winding, said end portion of said plunger defining a second surface disposed in facing relationship with respect to said first surface of said armature, at least one of said surfaces constituting a guide surface extending generally lengthwise of said axis and against which said other surface is adapted to be slidably seated;
means, spaced from said first surface lengthwise of said axis and extending radially inwardly from said excitation winding into contact with the longitudinal extending peripheral surface of said plunger, for establishing a fulcrum upon which said plunger, can pivot to selectively effect engagement between said first and second surfaces;
and
means for urging said plunger outwardly of said excitation winding in the direction away from its said one end, when said excitation winding is unenergized,
said surfaces further being configured and arranged such that, when said excitation winding is energized at a first predetermined level, contact is effected between said guide surfaces under a force sufficient to establish frictional forces therebetween precluding further displacement of said plunger in either direction along said axis and, when said excitation winding is subsequently energized at a second predetermined level greater than said first predetermined level, the frictional forces thereby established between said first and second surfaces and the force exerted on said plunger by said plunger urging means are insufficient to preclude further displacement of said plunger inwardly of said excitation winding towards its said one end under the influence of said electromagnetic field.

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Dependencies are inferred from the claim text.

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Abstract

Solenoid apparatus comprising:

an elongated excitation winding defining a longitudinal axis around which said excitation winding is disposed, along which said excitation winding extends, and with respect to which said excitation winding is radially spaced;
means for cooperating with said excitation winding, when said excitation winding is energized, for establishing a substantially low reluctance flux path for the electromagnetic field of said excitation winding, said flux path establishing means including a stationary armature positioned adjacent one end of said excitation winding and extending intermediate portions of said excitation winding disposed on opposite sides of said longitudinal axis to define a first surface positioned within said excitation winding intermediate said excitation winding and said axis and an elongated plunger disposed generally along said axis and having an end portion extending between radially disposed portions of said excitation winding, said end portion of said plunger defining a second surface disposed in facing relationship with respect to said first surface of said armature, at least one of said surfaces constituting a guide surface extending generally lengthwise of said axis and against which said other surface is adapted to be slidably seated;
means, spaced from said first surface lengthwise of said axis and extending radially inwardly from said excitation winding into contact with the longitudinal extending peripheral surface of said plunger, for establishing a fulcrum upon which said plunger, can pivot to selectively effect engagement between said first and second surfaces;
and
means for urging said plunger outwardly of said excitation winding in the direction away from its said one end, when said excitation winding is unenergized,
said surfaces further being configured and arranged such that, when said excitation winding is energized at a first predetermined level, contact is effected between said guide surfaces under a force sufficient to establish frictional forces therebetween precluding further displacement of said plunger in either direction along said axis and, when said excitation winding is subsequently energized at a second predetermined level greater than said first predetermined level, the frictional forces thereby established between said first and second surfaces and the force exerted on said plunger by said plunger urging means are insufficient to preclude further displacement of said plunger inwardly of said excitation winding towards its said one end under the influence of said electromagnetic field.

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