US3579048A - Electric safety-box - Google Patents

Electric safety-box Download PDF

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Publication number
US3579048A
US3579048A US811732A US3579048DA US3579048A US 3579048 A US3579048 A US 3579048A US 811732 A US811732 A US 811732A US 3579048D A US3579048D A US 3579048DA US 3579048 A US3579048 A US 3579048A
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US
United States
Prior art keywords
line
safety
relay
contact
box
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US811732A
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English (en)
Inventor
Rene Auffret
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NORD AVIAT SOC NATIONALE DE CO
NORD-AVIATION SOC NATIONALE DE CONSTRUCTIONS AERONAUTIQUES
Original Assignee
NORD AVIAT SOC NATIONALE DE CO
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NORD AVIAT SOC NATIONALE DE CO filed Critical NORD AVIAT SOC NATIONALE DE CO
Application granted granted Critical
Publication of US3579048A publication Critical patent/US3579048A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
    • H01H47/002—Monitoring or fail-safe circuits
    • H01H47/004—Monitoring or fail-safe circuits using plural redundant serial connected relay operated contacts in controlled circuit

Definitions

  • the present invention relates to a safety box giving an indication of a fault on an electric circuit, and more particularly for the prevention of accidents in an aircraft piloting control circuit as a result of the accidental sticking of relay contacts or of the fortuitous blocking of the control knobs in the closed position,
  • the fault which is most frequently encountered is that due to the accidental sticking of the contacts as a result of breaking the circtiit on an inductance and/or to the mechanical blocking of the control switches of the relays.
  • the invention provides a safety-box with crossed circuits, in which each relay actuating the main contacts on the lines comprises an auxiliary contact which forms part of the assembly of an auxiliary circuit, the said auxiliary contact of a circuit and the rest contact of the control button of the other circuit being connected in parallel between the winding of the safety relay of the said second circuit and a point on the line located downstream of the main contact of the said second circuit.
  • the electric safety-box according to the invention is further provided with an indicator pilot lamp on each auxiliary relay, in order to indicate its operation and in consequence the existence of a fault.
  • FIG. I is an electrical diagram of the conventional system of crossed relays
  • FIG. 2 is an electrical diagram of the box with an auxiliary relay in accordance with the invention
  • FIG. 3 is an electrical diagram showing the box according to the invention in a particular application for direct current to the control of the horizontal plane of an aircraft;
  • FIG. 4 is a diagrammatic view in perspective, showing the arrangement of the various parts in an elevator control system comprising the boxes of FIG. 3.
  • FIG. 1 a system with crossed relays.
  • the high and low circuits l and 2 each pass through two relays, of which the one which is open is the corresponding control relay 3 or 4, and the other normally closed relay is the corresponding safety relay 5 or 6.
  • Each top pushbutton 7 and bottom pushbutton 8 operates the coil of each corresponding control relay from a circuit in shunt to the main circuit and passing through the rest contact of the opposite pushbutton.
  • each control circuit is duplicated by an auxiliary safety circuit.
  • each control relay is provided with an auxiliary contract, one terminal of which takes the current of the opposite line downstream of the main control relay (the arrow f, indicates the direction of the direct current).
  • the corresponding circuit is interrupted when the other pushbutton is actuated, by means of this auxiliary contact which opens defective circuit by the safety relay which it controls.
  • control column 11 is equipped with two pushbuttons l2 and 13 and the electric safety-box 14 according to the invention controls the elevator surface 16 through the intennediary of a motor 17, while two limit switches 18 and 19 limit the extreme positions of the control surface and the circuit is protected by a circuit breaker 25.
  • An installation of this kind thus comprises the electric safety-box according to the invention, and is further provided with an auxiliary box 15 which essentially houses the diode equipment and other circuit elements appropriate to a directcurrent circuit such as that installed on aircraft.
  • the box 14 which is shown in more details in FIG. 2, comprises essentially the two control relays 20 and 21 and the two Nature of fault safety relays 22 and 23.
  • the auxiliary box which is shown in greater details in FIG. 3, comprises in the installation considered, four diodes 34, 35, 36 and 37 intended to prevent voltage surges during the breaking of the relays, two test indicators 32 and 33 and two diodes 38 and 39 for locking the main circuits, with their protection diodes and 41.
  • an emergency switch 24 is provided on the box 15 so as to enable manual isolation of the two circuits by opening the safety relays 22 and 23.
  • Table 1 given below summarizes the cases of faults and the operations which result from the action to be carried out in such cases.
  • the direct current circulates inthe lines in the direction of the arrow f,.
  • Button 12 is released, position R opens 23 by the circuit 60, 23, 61, 12, 62 taken off at 62 downstream of 21 in the position of closure.
  • the indicator 33 lights-up.
  • buttons 12 When the button 12 is depressed, it closes 21 which opens 22 by its auxiliary contact 63 having taken the current at 52 downstream of 20 in the position of closure.
  • the indicator 32 lights-up.
  • buttons 13 When the button 13 is depressed, it closes 20 which opens 28 by its auxiliary contact 64 having taken the current at 62 downstream of 21 in the closed position.
  • the indicator 33 lights-up.
  • the indicators 22 and 23 light-up.
  • the two indicators 32 and 33 light-up.
  • the electric box according to the invention provides a safety measure against all the defects of the relays or of the pushbuttons by means of a simple auxiliary circuit, and the fault is indicated by a light indicator.
  • the control relays only operate in the event of a fault, which increases their reliability.
  • the box can easily be changed by virtue of the arrangement of the output terminals which may be plug-in connections.
  • the present invention position and a safety contact in the position of rest, a first line' and a second line, both connected to a current source, a control relay and a safety relay series connected in each line, each relay simultaneously controlling a main contact and an auxiliary gauged contact, said main contact on said lines of said control relay being normally open and said main contact of said safety relays on said lines being nonnally closed in the position of rest of said pushbuttons, said auxiliary contact of said control relay of said first line being connected in parallel with said safety contact of said pushbutton in said second line between a point located downstream of said control relay of said second line and the control winding of said safety relay of said second line.
  • a safety-box as claimed in claim 1 characterized in that the auxiliary contact of the safety relay of the first line establishes, when it is closed, a short circuit line between the current source and a first pilot lamp which lights-up.
  • a safety-box as claimed in claim 1 characterized in that, relay, the pushbutton of the first line is in the operating position, the control relay of the corresponding line is closed, the safety relay of the second line being then excited by means of the auxiliary contact of the said relay, when the second line is supplied downstream of the main contact of the-control relay of said second line.
  • a safety-box as claimed in claim 1 characterized in that the main contact of a control relay of a first line being stuck and the corresponding pushbutton returning to its position of rest, the corresponding safety relay is excited by a circuit passing through the safety contact in the position of rest of said pushbutton, and being supplied with current downstream of said stuck main contact.

Landscapes

  • Safety Devices In Control Systems (AREA)
  • Switch Cases, Indication, And Locking (AREA)
  • Relay Circuits (AREA)
  • Maintenance And Inspection Apparatuses For Elevators (AREA)
US811732A 1968-04-04 1969-04-01 Electric safety-box Expired - Lifetime US3579048A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR147069 1968-04-04

Publications (1)

Publication Number Publication Date
US3579048A true US3579048A (en) 1971-05-18

Family

ID=8648612

Family Applications (1)

Application Number Title Priority Date Filing Date
US811732A Expired - Lifetime US3579048A (en) 1968-04-04 1969-04-01 Electric safety-box

Country Status (4)

Country Link
US (1) US3579048A (enrdf_load_stackoverflow)
DE (1) DE1917459C3 (enrdf_load_stackoverflow)
FR (1) FR1572325A (enrdf_load_stackoverflow)
GB (1) GB1216033A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070007087A1 (en) * 2004-02-26 2007-01-11 Mitsubishi Denki Kabushiki Kaisha Safety device of elevator and its operation testing method
US20180079622A1 (en) * 2015-03-20 2018-03-22 Otis Elevator Company Elevator testing arrangement
US10395869B2 (en) * 2016-01-20 2019-08-27 Schneider Electric Industries Sas Relay circuit and method for performing self-test of relay circuit

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303383A (en) * 1979-11-09 1981-12-01 Honeywell Inc. Condition control system with safety feedback means
DE3619723A1 (de) * 1986-06-12 1987-12-17 Kloeckner Moeller Elektrizit Kontaktbehaftete zusatzsteuerung fuer sicherheitsstromkreise

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2786989A (en) * 1954-09-28 1957-03-26 Rca Corp Automatic control alarm system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2786989A (en) * 1954-09-28 1957-03-26 Rca Corp Automatic control alarm system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070007087A1 (en) * 2004-02-26 2007-01-11 Mitsubishi Denki Kabushiki Kaisha Safety device of elevator and its operation testing method
US7575102B2 (en) * 2004-02-26 2009-08-18 Mitsubishi Denki Kabushiki Kaisha Safety device of elevator and its operation testing method
US20180079622A1 (en) * 2015-03-20 2018-03-22 Otis Elevator Company Elevator testing arrangement
US10395869B2 (en) * 2016-01-20 2019-08-27 Schneider Electric Industries Sas Relay circuit and method for performing self-test of relay circuit

Also Published As

Publication number Publication date
DE1917459B2 (de) 1979-11-15
GB1216033A (en) 1970-12-16
DE1917459A1 (de) 1969-11-13
FR1572325A (enrdf_load_stackoverflow) 1969-06-27
DE1917459C3 (de) 1980-07-24

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