US3748541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical safety control circuit for punch presses and the like
Assignee: Individual
•
Filing: 1972-07-26
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Granted: 1973-07-24
•
Expires: 1992-07-26
Abstract
Abstract A safety control circuit for punch presses and the like has two push buttons which must be pressed almost simultaneously, each push button permitting discharge of a capacitor through a relay coil, each relay having a normally closed switch connecting the capacitor to a electrical supply and a normally open switch which, when closed, can bypass the normally closed switch of the other relay. The circuit can be arranged to fail safe.
Inventors
- 👤 L Ginsberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:36
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/18; F16P3/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
118 words
An electrical control circuit comprising a capacitor, a first and a second relay each having normally closed switches in series with the capacitor for charging the capacitor from a supply, each relay having a coil connectable across the capacitor by a closable switch for energization of the coil by discharge of the capacitor therethrough, each coil when so energized opening its said normally closed switch, to disconnect the capacitor from the supply, but closing a normally open switch which provides a bypass for the normally closed switch of the other relay whereby if both relays are so energized the capacitor is reconnected to the supply, the relays thereby remaining energized as long as said closable switches remain closed.
Claim 2
Dependent Claim
118 words
An electrical control circuit comprising a capacitor, a first and a second relay each having normally closed switches in series with the capacitor for charging the capacitor from a supply, each relay having a coil connectable across the capacitor by a closable switch for energization of the coil by discharge of the capacitor therethrough, each coil when so energized opening its said normally closed switch, to disconnect the capacitor from the supply, but closing a normally open switch which provides a bypass for the normally closed switch of the other relay whereby if both relays are so energized the capacitor is reconnected to the supply, the relays thereby remaining energized as long as said closable switches remain closed.
Claim 3
Dependent Claim
30 words
A control circuit as claimed in claim 1, including a resistor normally in series with the capacitor but bypassed, if both relays are so energized, to keep the relays energized.
Claim 4
Dependent Claim
22 words
A control circuit as claimed in claim 1, including a solenoid that is connectable to the supply by energization of both relays.
Claim 5
Dependent Claim
66 words
A contron circuit as claimed in claim 1, wherein each said normally cloSed switch is in series with another normally closed switch openable by energization of the same relay coil, and wherein each said normally open switch is in series with another normally open switch closable by energization of the said relay coil, whereby failure of one of the switches does not render the circuit unsafe.
Claim 6
Dependent Claim
40 words
A control circuit as claimed in claim 4, wherein said other normally closed switch when opened by energization of a relay coil moves to form part of the bypass provided by closing the normally open switches of the other relay.
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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |