Patent US4069767A successfully refreshed from Google Patents.
Patent US4054935A successfully refreshed from Google Patents.
US4054935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety control circuit
Assignee: Individual
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Filing: 1976-05-28
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Granted: 1977-10-18
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Expires: 1996-05-28
Abstract
Abstract A safety control circuit for an electrically operable machine such as a punch press is described. The circuit includes input means for delivering electrical power to the machine and first and second relays, each including switching means and an associated relay coil for operating said switching means. The switching means of the relays are connected in said input means so that electrical power is delivered to the machine only when both relay coils are energized. First and second capacitors are associated respectively with said first and second relay coils and a source of direct current is provided for charging the capacitors. The direct current source is connectable with both capacitors through said switching means of said relays when both relay coils are de-energized, so that the capacitors are both normally charged when the circuit is at rest. First and second machine activating switch means are associated respectively with said first and second capacitors. Each of said switch means is arranged, when operated, to connect the relevant one of said capacitors with the associated relay coil to cause the capacitor to discharge into the coil and operate the relay. The circuit also includes resistor means connectable with either of said capacitors through the switching means of the relays, said switching means being arranged in the event that only one of said machine activating switch means is operated, to connect the capacitor associated with the other switch means to said resistor means, whereby, in use, the relevant capacitor will progressively discharge into the resistor means, preventing energization of the associated relay coil and hence activation of the machine after the level of charge in the capacitor has fallen below that required to energize the associated relay coil.
Inventors
- 👤 Leon Ginsberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:19
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/18; F16P3/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
264 words
A safety control circuit for an electrically operable machine, the circuit comprising: input means for delivering electrical power to the machine; first and second relays each including switching means and an associated relay coil for operating said switching means, the switching means of said relays being connected in said input means so that electrical power is delivered to the machine only when both relay coils are energized; first and second capacitors associated respectively with said first and second relay coils; a source of direct current for charging the capacitors, said direct current source being connectible with both capacitors through said switching means of said relays when both relay coils are de-energized, whereby the capacitors are both normally charged when the circuit is at rest; first and second machine activating switch means associated respectively with said first and second capacitors and each arranged, when operated, to connect the relevant one of said capacitors with the associated relay coil to cause the capacitor to discharge into the coil and operate the relay; and resistor means connectible with either of said capacitors through the switching means of said relays, said switching means being arranged, in the event that only one of said machine activating switch means is operated, to connect the capacitor associated with the other switch means to said resistor means whereby, in use, the relevant capacitor will progressively discharge into the resistor means, preventing energization of the associated relay coil and hence activation of the machine after the level of charge in the capacitor has fallen below that required to energize the relevant relay coil.
Claim 2
Dependent Claim
264 words
A safety control circuit for an electrically operable machine, the circuit comprising: input means for delivering electrical power to the machine; first and second relays each including switching means and an associated relay coil for operating said switching means, the switching means of said relays being connected in said input means so that electrical power is delivered to the machine only when both relay coils are energized; first and second capacitors associated respectively with said first and second relay coils; a source of direct current for charging the capacitors, said direct current source being connectible with both capacitors through said switching means of said relays when both relay coils are de-energized, whereby the capacitors are both normally charged when the circuit is at rest; first and second machine activating switch means associated respectively with said first and second capacitors and each arranged, when operated, to connect the relevant one of said capacitors with the associated relay coil to cause the capacitor to discharge into the coil and operate the relay; and resistor means connectible with either of said capacitors through the switching means of said relays, said switching means being arranged, in the event that only one of said machine activating switch means is operated, to connect the capacitor associated with the other switch means to said resistor means whereby, in use, the relevant capacitor will progressively discharge into the resistor means, preventing energization of the associated relay coil and hence activation of the machine after the level of charge in the capacitor has fallen below that required to energize the relevant relay coil.
Claim 3
Dependent Claim
99 words
A circuit as claimed in claim 1, which is designed to operate in a maintained mode, and which further comprises: a second source of direct current connectable with each of said first and second capacitors through the switching means of the respective relays, said switching means being arranged so that each capacitor is connected to said second source of direct current when the relay coil associated with the capacitor is in the energized condition, whereby charging current for the capacitor is maintained after the associated relay coil has been energized upon operation of the relevant machine activating switch means.
Claim 4
Dependent Claim
161 words
A circuit as claimed in claim 1 which is designed to operate in a pulse mode, wherein said input means is connected to a solenoid arranged to activate the machine when supplied with a pulse of electrical energy, and wherein in the circuit further comprises: pulse duration - determining resistor means connectable with said capacitors through the switching means of the respective relays, said switching means being arranged so that each capacitor is connected with said resistor means when the relay coil associated with the capacitor is in the energized condition, whereby operation of both machine activating switch means in use causes the capacitors both to discharge into said pulse duration-determining resistor means and to energize the associated relay coils, so that electrical energy is delivered to said solenoid until the level of charge in one of said capacitors falls to a value at which the associated relay coil drops out, causing said input means to be disconnected from the solenoid.
Claim 5
Dependent Claim
81 words
A circuit as claimed in claim 3, further comprising: resistor means connectable in series with said relay coils through said switching means when both of said relay coils are in the de-energized condition, said resistor means being arranged so that, if at least one of said machine activating switch means is maintained in the operated condition when both relay coils are de-energized, the voltage drop across said resistor means will prevent recharging of the capacitor associated with the operated switch means.
Claim 6
Dependent Claim
40 words
A circuit as claimed in claim 1, wherein said input means is arranged to deliver alternating electrical current to the machine, and wherein said source of direct current for charging the capacitors comprises diode means connected in said input means.
Claim 7
Dependent Claim
36 words
A circuit as claimed in claim 5, wherein said diode means comprises first and second diodes connectable respectively with said first and second capacitors, whereby each capacitor is provided with a separate source of direct current.
Claim 8
Dependent Claim
26 words
A circuit as claimed in claim 1, wherein the said resistor means is adjustable to allow variation in the discharge time of a capacitor connected thereto.
Claim 9
Dependent Claim
40 words
A circuit as claimed in claim 1, wherein said resistor means comprises first and second resistors connectable with the respective capacitors through said switching means of the relays, whereby each resistor forms a discharge path only for the associated capacitor.
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) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |