US3890833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure measuring apparatus
Assignee: Precisa AG Rechenmaschinenfabrik
•
Filing: 1973-08-13
•
Granted: 1975-06-24
•
Expires: 1993-08-13
Abstract
Abstract Pressure measuring apparatus with electric force compensation has a magnet coil system exerting a counterforce on a pressure sensor. The system has at least two magnet coils which are controllable independently of each other. One magnet coil is for balancing a preliminary load and the second magnet coil is for balancing the force to be determined. The second coil is connected to a control circuit provided with a system for sensing the position of the sensor and a system for sensing the current required to balance the preliminary load. Once the preliminary force is balanced by one coil further applied force is measured by the current in the other coil.
Inventors
- 👤 Jon Peer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:45
CPC Classifications
G; G01; G01L; G01L5/00; G01L5/04; G01L5/10; G01L5/106; G01G; G01G7/00; G01G7/02; G01G7/04; G01G7/045; G01L5/108
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
234 words
Measuring apparatus comprising: a force sensing unit mounted for movement in response to a force to be measured and having a rest position from which it is displaced to an extent dependent upon the magnitude of said force; a magnetic structure comprising a permanent magnet component including a core portion and a composite coil component comprising first and second separately energizable coils mounted on said core portion for displacement relative thereto, one of said components being stationary and the other component being movable and interconnected with said force sensing unit for balancing a force applied thereto; means for sensing an initial displacement of said force sensing unit from its rest position and providing a corresponding output current in said first coil which produces a corresponding counter balancing electromagnetic force that restores said force sensing unit to its rest position; and means for sensing the current in said first coil and maintaining an output current in said second coil to hold said force sensing unit in its rest position, the force applied to said force sensing unit being now balanced by the electromagnetic force produced by said second coil so that the current in said first coil drops to zero, whereby subsequent forces applied to said force sensing unit are balanced by an electromagnetic force produced by said first coil and measured relative to the initially applied force by the current in said first coil.
Claim 2
Dependent Claim
234 words
Measuring apparatus comprising: a force sensing unit mounted for movement in response to a force to be measured and having a rest position from which it is displaced to an extent dependent upon the magnitude of said force; a magnetic structure comprising a permanent magnet component including a core portion and a composite coil component comprising first and second separately energizable coils mounted on said core portion for displacement relative thereto, one of said components being stationary and the other component being movable and interconnected with said force sensing unit for balancing a force applied thereto; means for sensing an initial displacement of said force sensing unit from its rest position and providing a corresponding output current in said first coil which produces a corresponding counter balancing electromagnetic force that restores said force sensing unit to its rest position; and means for sensing the current in said first coil and maintaining an output current in said second coil to hold said force sensing unit in its rest position, the force applied to said force sensing unit being now balanced by the electromagnetic force produced by said second coil so that the current in said first coil drops to zero, whereby subsequent forces applied to said force sensing unit are balanced by an electromagnetic force produced by said first coil and measured relative to the initially applied force by the current in said first coil.
Claim 3
Dependent Claim
45 words
Apparatus as set forth in claim 1, including a first order lever having one end pivotally connected to said magnetic structure and the other end pivotally connected to said force sensing unit, said first order lever being pivoted to a fixed point in said apparatus.
Claim 4
Dependent Claim
30 words
Apparatus as set forth in claim 2, including a parallel-motion linkage supporting said force sensing unit, one link of which is formed by one arm of said first order lever.
Claim 5
Dependent Claim
51 words
Apparatus as set forth in claim 1, including a lever having one end pivoted to a fixed point in the apparatus, the other end pivotally connected to said force sensing unit, and an intermediate point pivotally connected to a further force sensing unit acted on by large forces to be measured.
Claim 6
Dependent Claim
29 words
Apparatus as set forth in claim 4, including a parallel-motion linkage supporting said further force sensing unit, one link of which is formed by one arm of said lever.
Claim 7
Dependent Claim
24 words
Apparatus as set forth in claim 1 in which said means for sensing initial displacement of said force sensing unit is a photo-electric system.
Claim 8
Dependent Claim
100 words
Apparatus as set forth in claim 6, in which said means for sensing initial displacement of said force sensing unit includes a shutter linked to said force sensing unit, a light source, two photo-sensitive elements, a comparator connected to receive the outputs of said photo-sensitive elements and providing an output indicative of the difference therebetween, said means for sensing initial displacement of said force sensing unit being so adjusted that when said force sensing unit is in said rest position no output is produced by said comparator, an output from said comparator thus indicating displacement of said force sensing unit.
Claim 9
Dependent Claim
77 words
Apparatus as set forth in claim 1 in which said means For sensing the current in said first coil and maintaining an output current in said second coil includes a resistance in series with said first coil, a circuit measuring the voltage across said resistance and providing a coded signal significant of said current, a memory holding said coded signal, and a current source controlled by said memory and maintaining said output current in said second coil.
References Cited (Backward Citations)
US2675222A
Cited
US2832535A
Cited
US3509763A
Cited
US3685604A
Cited
US3617370A
Cited
US3648793A
Cited
US3786883A
Cited
US3799281A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |