US3893052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shock-resistant indicating device
Assignee: General Electric Co
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Filing: 1974-09-26
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Granted: 1975-07-01
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Expires: 1994-09-26
Abstract
Abstract In the disclosed indicating device a plunger is normally held in a retracted, non-indicating position by a permanent magnet. An electro-magnet, upon energization, develops a flux opposing the holding flux of the permanent magnet to allow the plunger to be displaced by a spring into its indicating position. The magnetic circuit for most of the holding flux from the permanent magnet comprises a wall of magnetic material containing an aperture through which the plunger extends with a loose fit and through which it moves upon displacement by the spring. For preventing undesired displacement of the plunger out of its retracted position as a result of mechanical shocks and vibrations, there is developed on the plunger in the region where it passes through the aperture a radially-acting magnetomotive force that holds the outer periphery of the plunger in contact with a restricted portion of the internal wall of the aperture.
Inventors
- 👤 Peter Kotos
- 👤 Harry G Kokolis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:55
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/06; H01F7/08; H01F7/16; H01F7/1607; H01F7/1615; G; G08; G08B; G08B5/00; G08B5/22; G08B5/32; H01F7/121; H01F7/122; H01H; H01H71/00; H01H71/10; H01H71/1054; H01H71/12; H01H71/24; H01H71/32; H01H71/321; H01H71/322
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
260 words
A shock-resistant electromechanical indicating device comprising: a. spaced-apart first and second walls and a frame connecting said walls, said walls and said frame being made of a highly magnetically permeable material, and said first wall containing an aperture; b. a reciprocally-movable, generally-cylindrical plunger also made of highly magnetically permeable material extending into said aperture with a loose fit, said plunger having a normal retracted position and an extended indicating position; c. spring means normally producing a force urging said plunger toward said extended position; d. guide means for guiding said plunger for a movement in a direction substantially parallel to the longitudinal axis of said plunger but allowing the outer periphery of said plunger when the plunger is in its retracted position to contact the internal wall of said aperture along a restricted portion of said internal wall; e. a permanent magnet member fixed relative to said second wall producing a first magnetomotive force which is in opposition to and of a magnitude greater than said spring force and a second magnetomotive force applied in a radial direction to said plunger at said aperture; f. said second magnetomotive force normally holding the outer periphery of said plunger in contact with said restricted portion of the internal wall of said aperture when the plunger is in said retracted position; and g. a normally-deenergized coil surrounding but spaced from said plunger energizable to produce flux in opposition to that from said permanent magnet, thus reducing said first magnetomotive force sufficiently to allow said spring to drive said plunger to its extended position.
Claim 2
Dependent Claim
260 words
A shock-resistant electromechanical indicating device comprising: a. spaced-apart first and second walls and a frame connecting said walls, said walls and said frame being made of a highly magnetically permeable material, and said first wall containing an aperture; b. a reciprocally-movable, generally-cylindrical plunger also made of highly magnetically permeable material extending into said aperture with a loose fit, said plunger having a normal retracted position and an extended indicating position; c. spring means normally producing a force urging said plunger toward said extended position; d. guide means for guiding said plunger for a movement in a direction substantially parallel to the longitudinal axis of said plunger but allowing the outer periphery of said plunger when the plunger is in its retracted position to contact the internal wall of said aperture along a restricted portion of said internal wall; e. a permanent magnet member fixed relative to said second wall producing a first magnetomotive force which is in opposition to and of a magnitude greater than said spring force and a second magnetomotive force applied in a radial direction to said plunger at said aperture; f. said second magnetomotive force normally holding the outer periphery of said plunger in contact with said restricted portion of the internal wall of said aperture when the plunger is in said retracted position; and g. a normally-deenergized coil surrounding but spaced from said plunger energizable to produce flux in opposition to that from said permanent magnet, thus reducing said first magnetomotive force sufficiently to allow said spring to drive said plunger to its extended position.
Claim 3
Dependent Claim
20 words
An electromechanical indicating device as defined in claim 1 in which said permanent magnet member is of cobalt-rare earth material.
Claim 4
Dependent Claim
18 words
An electromechanical indicating device as defined in claim 2 in which the material of said magnet comprises cobalt-samarium.
Claim 5
Dependent Claim
42 words
An electromechanical indicating device as defined in claim 1 in which said guide means comprises a cavity in said plunger extending generally parallel to the longitudinal axis of the plunger and a pin member of nonmagnetic material fitting loosely within said cavity.
Claim 6
Dependent Claim
46 words
An electromechanical indicating device as defined in claim 1 in which said frame comprises a hollow generally cylindrical member of highly magnetically permeable material surrounding said plunger, said permanent magnet, and said electromagnet which is effective to substantially exclude stray magnetic fields from said surrounded components.
Claim 7
Dependent Claim
62 words
An electromechanical indicating device as defined in claim 1 in which: a. said plunger member in its retracted position is held against a magnetic flux-controlling member, and b. said guide means comprises a cavity in one of said members extending generally parallel to the direction of movement of the plunger and a guide pin of non-magnetic material fitting loosely in the cavity.
Claim 8
Dependent Claim
62 words
An electromechanical indicating device as defined in claim 1 in which said permanent magnet is located adjacent a pole piece disposed between said magnet and said second wall, said pole piece and said magnet having longitudinal axes that are generally axially aligned, said pole piece extending radially outward from its longitudinal axis not substantially beyond the outer periphery of said permanent magnet.
Claim 9
Dependent Claim
90 words
An indicating device as defined in claim 1 comprising a cap on the outer end of said plunger that is larger in diameter than the plunger, the outer periphery of said cap fitting in the bore of hollow structure on said first wall to provide around the exterior of the cap a restricted tortuous path between said aperture and the surrounding atmosphere, said bore being sufficiently large relative to said cap as to prevent the cap from interfering with contact between said plunger and said internal wall of the aperture.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |