US4433309A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity switch with built-in test circuit
Assignee: BEGHARD BALLUFF FABRIK FEINMECHANISCHER ERZEUGNISSE
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Filing: 1981-02-25
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Granted: 1984-02-21
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Expires: 2001-02-25
Abstract
Abstract An inductive proximity switch with a built-in testing circuit for monitoring movable elements in which an oscillator has an inductive control element, the impedance of which varies in response to approaching elements with a built-in electrical tester for monitoring the correct functioning of the proximity switch wherein the tester has an electrically switchable damping circuit for damping the oscillator for test purposes.
Inventors
- 👤 Rolf Hermle
- 👤 Heinz Kammerer
- 👤 Hans Langheinrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:50
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/94; H03K17/945
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
83 words
Proximity switch for the monitoring of movable elements comprising an oscillator having an oscillatory circuit with an inductive control element variable in its impedance due to approaching elements and an electric monitoring means for monitoring the correct functioning of the proximity switch, characterized in that the monitoring means has an electrically switchable damping circuit (V, K; T5, R10-R12, K1; T6, R13, Rx, K2) for testing purposes, the oscillator (L, C1, R1, R2, T1, T2) being dampable with the aid of said damping circuit.
Claim 2
Dependent Claim
83 words
Proximity switch for the monitoring of movable elements comprising an oscillator having an oscillatory circuit with an inductive control element variable in its impedance due to approaching elements and an electric monitoring means for monitoring the correct functioning of the proximity switch, characterized in that the monitoring means has an electrically switchable damping circuit (V, K; T5, R10-R12, K1; T6, R13, Rx, K2) for testing purposes, the oscillator (L, C1, R1, R2, T1, T2) being dampable with the aid of said damping circuit.
Claim 3
Dependent Claim
50 words
Proximity switch according to claim 1 comprising an inductive feeler head with a feeler coil in the oscillatory circuit of the oscillator, characterized in the provision of means for at least partially short-circuiting of the feeler coil (L) when the damping circuit (V, K; T5, R10-R12, K1) is switched in.
Claim 4
Dependent Claim
45 words
Proximity switch according to claim 2 comprising a feeler coil with tab, characterized in the provision of means for a short-circuiting of a coil portion (L1) of the feeler coil (L), said coil portion being disposed between the tab and one of the coil ends.
Claim 5
Dependent Claim
31 words
Proximity switch according to claim 2 or 3, characterized in that said short-circuiting means comprises a testing switch (K) connected in parallel with at least a portion of said feeler coil.
Claim 6
Dependent Claim
20 words
Proximity switch according to claim 4, characterized in that a predetermined series resistor (R12) is inserted in the short-circuiting means.
Claim 7
Dependent Claim
41 words
Proximity switch according to claim 3 characterized in that said short-circuiting means comprises a testing transistor having a collector-emitter circuit in parallel with said coil and a base and means including a testing switch for switching the potential of said base.
Claim 8
Dependent Claim
86 words
Proximity switch as in claim 6 characterized in the provision of a power source having a pair of terminals, means connecting said collector to the tab of said feeler coil, means connecting said emitter to one end of said feeler coil, means connecting said one end to one terminal of said source, a testing switch (K1) and a current limiting resistor (R11) for connecting the transistor base to the other terminal of the power source and a shunt (R10) connected between the transistor base and emitter.
Claim 9
Dependent Claim
25 words
Proximity switch according to claim 7, characterized in the provision of a filtering element (C3) connected in the base-emitter circuit of the testing transistor (T5).
Claim 10
Dependent Claim
31 words
Proximity switch according to claim 6, characterized in that a predetermined resistor (R12) is inserted between the tab of the feeler coil (L) and the collector of the testing transistor (T5).
Claim 11
Dependent Claim
70 words
Proximity switch according to claim 1 adapted to be activated at a predetermined distance of said approaching elements comprising a resistor connected in parallel with at least a portion of said control element determining said distance, characterized in that the damping circuit is designed such that the effective resistivity of the resistor (Rx, Rx') determining said distance is reducible when the damping circuit (T6, R13, Rx', K2) is switched in.
Claim 12
Dependent Claim
48 words
Prosimity switch according to claim 10, characterized in that said damping circuit comprises a testing switch (K2) and in that said resistor determining said distance is subdivided into two resistors (Rx, Rx'), a short-circuiting of one of these (Rx') being initiated by actuation of the testing switch (K2).
Claim 13
Dependent Claim
48 words
Proximity switch according to claim 11, characterized in that the collector-emitter circuit of a switching transistor (T6) is connected in parallel to the resistor (Rx'), which is capable of being short circuited, the base potential of said switching transistor being controllable by actuation of the testing switch (K2).
Claim 14
Dependent Claim
65 words
Proximity switch according to claim 1 characterized in that the monitoring means is connected with switching means (On, Off, Relay 1 to Relay 7) of a starting control circuit, said monitoring means being connected with said switching means such that each starting procedure necessarily initiates an electrical switching of the damping circuit (T5, R10-R12, C3) to dampen the oscillator (C, C1, R1, R2, T1, T2).
Claim 15
Dependent Claim
33 words
Proximity switch according to claim 13, characterized in that the switching means of the starting control circuit (FIG. 2) is a self-controlling switching means comprising means for testing the dampability of the oscillator.
Claim 16
Dependent Claim
51 words
Proximity switch according to claim 13, characterized in that said proximity switch is connected in parallel to a further proximity switch and that the switching means of the starting control circuit (FIG. 2) is a self-controlling switching means comprising means for testing the dampability of the oscillators of the proximity switches.
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) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |