US3560800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical safety structure
Assignee: Individual
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Filing: 1967-12-28
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Granted: 1971-02-02
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Expires: 1987-12-28
Abstract
Abstract An electrical safety structure designed to prevent injury to an operator of a machine. This safety structure includes a safety circuit and an operating circuit for operating a machine when this latter circuit is closed. A pair of series-connected normally closed switches are located in the safety circuit and a pair of series-connected normally open switches are located in the control circuit and are respectively coupled with the normally open switches to form with the latter a pair of switch units spaced from each other by a distance too great to be operated by one hand of the operator. A control switch means maintains part of the operating circuit closed as long as the normally closed switches of the safety circuit remain in their closed positions and operates to enable the operator to actuate both of the switch units simultaneously to provide for simultaneous closing of both normally open switches along with simultaneous opening of both normally closed switches so that the operating circuit will be closed by the pair of series-connected normally open switches only by simultaneous actuation of both switch units and not by separate actuation of either one of the switch units. Because the operator must use both hands for simultaneous operation of the switch units, the operator''s hands cannot be located at part of the machine where the operator can be injured when the machine is actuated by closing the operating circuit.
Inventors
- 👤 Morris Weidenfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:07
CPC Classifications
F; F16; F16P; F16P3/00; F16P3/18; F16P3/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
353 words
An electrical apparatus, a safety assembly comprising and operating circuit and a safety circuit, said operating circuit having a first and second series-connected normally open switches and said safety circuit having a third and fourth seriesconnected normally closed switches respectively coupled with said first and second normally open switches to form a pair of switch units to be manually actuated by opening said normally closed switches simultaneously with the closing of said normally open switches, one side of said first switch connected to one side of a third switch and to one side of a source of alternating current, said switch units being spaced apart from each other by a distance small enough to be operated by two hands but too great to be operated by one hand of the operator, one side of a first relay coil connected to one side of said fourth switch, the other side of said first relay coil connected to the other side of said source of alternating current, a fifth switch controlled by said first relay coil in a closed position when said first relay coil is energized, said fifth switch connected to one side of said second switch and to one side of a second relay coil and to one side of a third coil, the second side of said second relay coil and the third coil being connected to said other side of said source of said alternating current, a sixth switch, sAid second relay coil controlling said sixth switch, said first relay coil when deenergized operating to open said fifth switch with a time lag sufficiently great to enable the operator to simultaneously close both of said normally open switches and open both of said normally closed switches to close said sixth switch by means of a current passing through said second relay coil, said operating circuit having a bypass circuit portion which includes said sixth switch connected in parallel with said fifth switch, said bypass circuit portion being energized when said time lag lapses, said third coil controlling said electrical apparatus and being directly energized when said second relay coil is energized.
Claim 2
Dependent Claim
353 words
An electrical apparatus, a safety assembly comprising and operating circuit and a safety circuit, said operating circuit having a first and second series-connected normally open switches and said safety circuit having a third and fourth seriesconnected normally closed switches respectively coupled with said first and second normally open switches to form a pair of switch units to be manually actuated by opening said normally closed switches simultaneously with the closing of said normally open switches, one side of said first switch connected to one side of a third switch and to one side of a source of alternating current, said switch units being spaced apart from each other by a distance small enough to be operated by two hands but too great to be operated by one hand of the operator, one side of a first relay coil connected to one side of said fourth switch, the other side of said first relay coil connected to the other side of said source of alternating current, a fifth switch controlled by said first relay coil in a closed position when said first relay coil is energized, said fifth switch connected to one side of said second switch and to one side of a second relay coil and to one side of a third coil, the second side of said second relay coil and the third coil being connected to said other side of said source of said alternating current, a sixth switch, sAid second relay coil controlling said sixth switch, said first relay coil when deenergized operating to open said fifth switch with a time lag sufficiently great to enable the operator to simultaneously close both of said normally open switches and open both of said normally closed switches to close said sixth switch by means of a current passing through said second relay coil, said operating circuit having a bypass circuit portion which includes said sixth switch connected in parallel with said fifth switch, said bypass circuit portion being energized when said time lag lapses, said third coil controlling said electrical apparatus and being directly energized when said second relay coil is energized.
Claim 3
Dependent Claim
24 words
The combination of claim 1 and wherein said safety circuit is a direct current circuit while said operating circuit is an alternating current circuit.
Claim 4
Dependent Claim
47 words
The combination of claim 1 and wherein the electrical apparatus includes a machine and in said operating circuit a plurality of electrically operable control units for controlling said machine so that the latter cannot be operated unless both said switch units are simultaneously actuated by the operator.
Claim 5
Dependent Claim
83 words
The combination of claim 3 and wherein the machine has a moving means and a pair of members one of which is movable by said moving means toward the other for carrying out the work of the machine, said members defining between themselves a space beyond which the operator must keep his hands in order not to be injured, and one of said control units being operatively connected with said moving means to actuate the latter when said one control unit is energized.
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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |