EP0287531A2 - Dichter elektrischer Druckschalter für pneumatische oder hydraulische Kreisläufe - Google Patents

Dichter elektrischer Druckschalter für pneumatische oder hydraulische Kreisläufe Download PDF

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Publication number
EP0287531A2
EP0287531A2 EP88830158A EP88830158A EP0287531A2 EP 0287531 A2 EP0287531 A2 EP 0287531A2 EP 88830158 A EP88830158 A EP 88830158A EP 88830158 A EP88830158 A EP 88830158A EP 0287531 A2 EP0287531 A2 EP 0287531A2
Authority
EP
European Patent Office
Prior art keywords
electrical connection
stopper
connection members
external electrical
biasing spring
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.)
Ceased
Application number
EP88830158A
Other languages
English (en)
French (fr)
Other versions
EP0287531A3 (de
Inventor
Virginio Maggioni
Alessandro Giupponi
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.)
Industrie Magneti Marelli SRL
Marelli Europe SpA
Original Assignee
Industrie Magneti Marelli SRL
Magneti Marelli SpA
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 Industrie Magneti Marelli SRL, Magneti Marelli SpA filed Critical Industrie Magneti Marelli SRL
Publication of EP0287531A2 publication Critical patent/EP0287531A2/de
Publication of EP0287531A3 publication Critical patent/EP0287531A3/de
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/34—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by diaphragm
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/26—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/26—Details
    • H01H35/2607—Means for adjustment of "ON" or "OFF" operating pressure
    • H01H35/2614—Means for adjustment of "ON" or "OFF" operating pressure by varying the bias on the pressure sensitive element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/02—Bases, casings, or covers
    • H01H9/04—Dustproof, splashproof, drip-proof, waterproof, or flameproof casings

Definitions

  • the present invention relates in general to electrical pressure switches or pressostats for electrical or pneumatic circuits.
  • the invention concerns a switch of the type including a substantially cylindrical hollow body having at one end a tubular connector for connection to a hydraulic or pneumatic circuit and carrying at its other end the external electrical connection members intended for connection to an electrical signalling circuit.
  • the body houses a pair of fixed contacts connected to the external electrical connection members and cooperating with a movable contact carried by a slidable push rod located at the end with the tubular connector and movable axially to separate the movable contact from the fixed contacts against the action of a biasing spring which reacts against an abutment located at the end with the external electrical connection members and adjustable axially relative to the body by means of a threaded coupling for calibrating the spring.
  • the body is normally closed at the end opposite the tubular connector by means of a base through which the external electrical connection members project.
  • the adjustment of the abutment for the biasing spring to calibrate it consequently involves difficult and inconvenient operations in that it is necessary to enter the body through the openings for the passage of the external electrical connection members with a screwdriver or like tool for screwing or unscrewing the abutment for the biasing spring.
  • the object of the present invention is to avoid this disadvantage and to provide an electrical switch of the type defined at the beginning with a conformation such as to make the operations for adjusting the abutment for the biasing spring considerably easier and more convenient.
  • this object is achieved by virtue of the fact that the end of the body opposite the tubular connector is open and receives a closure stopper carrying the external electrical connection members and adapted to be sealed to the body after the adjustment of the abutment for the biasing spring.
  • the calibration of the biasing spring may be carried out during assembly of the switch in an appreciably more convenient, easier and more precise manner, the abutment being reached through the open end of the body before the application of the closure stopper.
  • the closure stopper is conveniently fixed to the body by seaming.
  • the body also has radial vent apertures opening into an annular groove in the outside of the body, within which is housed a resilient sealing ring which cooperates with the holes as a check valve.
  • the closure stopper is of plastics material and the external electrical connection members are integrated with the stopper by co-moulding.
  • an electrical pressure switch or pressostat applicable to hydraulic or pneumatic circuits is generally indicated 1.
  • the switch 1 includes centrally a cylindrical hollow body 2, normally of metal, forming at one end a tubular connector 3 for connection to the hydraulic or pneumatic circuit and being open at its opposite end, indicated 4.
  • a tubular member 5 bearing against the base of the connector 3 with the interposition of a diaphragm 6 which sealingly isolates the cavity in the body 2 from the tubular connector 3.
  • a push rod 7 bearing against the diaphragm 6 is slidable axially through the member 5 and carries an annular movable contact 8.
  • the movable contact 8 cooperates with a pair of fixed contacts 9 carried by respective conductive bars 10 which extend axially within the cavity of the body 2.
  • a tubular member 11 is clamped inside the two bars 10 and has internal threading 12 into which is screwed an externally-threaded abutment 13 having a notch 14 for a screwdriver in its outer face.
  • a helical compression spring 15 reacts at one end against the inner face of the abutment 13, while its opposite end reacts against a plate 16 adjacent the movable contact 8.
  • the spring 15 urges the movable contact 8 to close against the fixed contacts 9, while the axial sliding of the push rod 7 inwardly of the body 2, under the action of the pressure coming from the connector 3 in use, causes the separation of the movable contact 8 from the fixed contact 9 against the action of the spring 15.
  • a retaining bush, indicated 17, bears on the end of the tubular member 11 opposite the tubular connector 3 and is locked axially to the body 2, by means of internal retaining appendages 18 of the body 2, which are upset radially.
  • the body 2 has a portion 2a which terminates in correspondence with the open end 4 and in which is engaged a closure stopper 19 of moulded plastics material.
  • the stopper 19 has an annular sealing ring 20 in hermetic contact with the surface of the portion 2a of the body 2 and is locked thereto by seaming, by means of the folding of the end edge 21 of the portion 2a.
  • Two electrical connection blades 22 are co-moulded in the body 19 and extend within a tubular connection portion 23 of the stopper 19 with their inner ends, indicated 22a, kept in contact with the two conductive bars 10.
  • the blades 22 are intended for connection to an electrical signalling or control circuit in use.
  • the body conveniently has a series of radial vent holes 24 opening into an annular external groove 25 housing a resilient ring 26 which cooperates with these holes 24 as a check valve.
  • the configuration of the switch 1 described above enables the spring 15 to be calibrated conveniently and easily during assembly of the switch by the screwing and unscrewing of the abutment 13 relative to the tubular element 11.
  • the calibration may be carried out before the stopper 19 is applied, a screwdriver or like tool being introduced through the open end 4 of the body 2 and used to rotate the abutment 13. After the abutment 13 has been adjusted, the stopper 19 is applied and clamped in place by the seaming of the edge 21.
  • FIGS 3 and 4 show two constructional variants of the switch according to the invention: these variants are generally similar to the embodiment described above and only the differences will be described in detail, the same reference numerals being used for identical or similar parts.
  • the portion 2a of the body 2 has a longer axial length than that of the embodiment of Figure 1.
  • the stopper of the version of Figure 3, indicated 19a has a correspondingly greater axial dimension and a substantially cylindrical general configuration, and is not provided with a sealing ring 20. In this case, the vent holes 24 with the resilient sealing ring 26 may consequently be omitted.
  • the stopper indicated 19b, also has a generally cylindrical configuration without a sealing ring, and a connection clamp 27 is the connection of respective electrical cables 28 provided at the ends with sealed connectors of conventional type, one of which is indicated 29.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
EP88830158A 1987-04-14 1988-04-12 Dichter elektrischer Druckschalter für pneumatische oder hydraulische Kreisläufe Ceased EP0287531A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT5323587U IT210649Z2 (it) 1987-04-14 1987-04-14 Interruttore elettrico a pressione a tenuta stagna per circuiti idraulici o pneumatici
IT5323587U 1987-04-14

Publications (2)

Publication Number Publication Date
EP0287531A2 true EP0287531A2 (de) 1988-10-19
EP0287531A3 EP0287531A3 (de) 1990-07-04

Family

ID=11281100

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88830158A Ceased EP0287531A3 (de) 1987-04-14 1988-04-12 Dichter elektrischer Druckschalter für pneumatische oder hydraulische Kreisläufe

Country Status (2)

Country Link
EP (1) EP0287531A3 (de)
IT (1) IT210649Z2 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2336212A (en) * 1998-04-06 1999-10-13 Ranco Controls Ltd Pressure sensor with adjustment means
WO2008145150A1 (en) * 2007-05-29 2008-12-04 Norgren Gmbh Pressure switch with an integrated diaphragm and switch
CN110454531A (zh) * 2019-07-11 2019-11-15 江苏长龄液压股份有限公司 一种中心设有检测介质的弹簧

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2844679A (en) * 1954-03-01 1958-07-22 Selby W Brewer Pressure responsive switch
DE3326680A1 (de) * 1983-07-23 1985-01-31 Robert Scheuffele GmbH & Co KG, 7120 Bietigheim-Bissingen Druckschalter
DE3603059A1 (de) * 1986-02-01 1987-08-06 Scheuffele Robert Gmbh Co Kg Druckschalter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2336212A (en) * 1998-04-06 1999-10-13 Ranco Controls Ltd Pressure sensor with adjustment means
WO2008145150A1 (en) * 2007-05-29 2008-12-04 Norgren Gmbh Pressure switch with an integrated diaphragm and switch
US8173918B2 (en) 2007-05-29 2012-05-08 Norgren Gmbh Pressure switch with an integrated diaphragm and switch
CN110454531A (zh) * 2019-07-11 2019-11-15 江苏长龄液压股份有限公司 一种中心设有检测介质的弹簧

Also Published As

Publication number Publication date
IT8753235V0 (it) 1987-04-14
EP0287531A3 (de) 1990-07-04
IT210649Z2 (it) 1989-01-11

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