US3588403A - Time-lag pressure responsive switches - Google Patents

Time-lag pressure responsive switches Download PDF

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Publication number
US3588403A
US3588403A US789300A US3588403DA US3588403A US 3588403 A US3588403 A US 3588403A US 789300 A US789300 A US 789300A US 3588403D A US3588403D A US 3588403DA US 3588403 A US3588403 A US 3588403A
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United States
Prior art keywords
pressure responsive
pressure
timelag
contact
responsive switch
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
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US789300A
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English (en)
Inventor
Jean Piret
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.)
Automobiles Peugeot SA
Renault SA
Original Assignee
Automobiles Peugeot SA
Renault SA
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 Automobiles Peugeot SA, Renault SA filed Critical Automobiles Peugeot SA
Application granted granted Critical
Publication of US3588403A publication Critical patent/US3588403A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • a timelag pressure responsive switch comprising a pressure chamber closed by a flexible diaphragm of which the movable portion is displaceable against the resistance of an antagonistic spring for actuating a rod controlling a back contact, characterized in that it comprises a timelag device for retarding the opening of said contact and adjusting the rate of delivery of the fluid under pressure to said chamber for actuating said pressure responsive switch, the timelag characteristic of this device increasing with the fluid viscosity while preserving the fast opening contact characteristic.
  • This invention relates to a timelag pressure responsive switch.
  • Pressure responsive switches comprise a flexible diaphragm responsive to the pressure of the fluid in the circuit to be controlled, the movement of this diaphragm controlling to this end the opening of closing of an electric contact.
  • these pressure responsive switches are used for controlling either the ignition of a pilot lamp or an electrical circuit supplying energizing current to a plurality of relays or apparatus to be protected.
  • a known application of this type of pressure responsive switch for example of the oil-pressure type, consists in placing its contacts in series with the control of the starter motor of an internal combustion engine ofa vehicle or else with a view to prevent the starter pinions from being damaged as a consequence of an untimely closing of said contacts when the engine is running.
  • This pressure responsive switch comprising a pressure chamber closed by a flexible diaphragm acting against the resistance of an antagonistic spring on a rod controlling a back contact, is characterized in that it comprises timelag means adapted to retard the contact opening and adjust the rate of delivery of the pressure fluid to the pressure chamber for actuating the pressure responsive switch, the effect of said timelag means increasing with the fluid viscosity while maintaining a quick opening contact characteristic.
  • FIG. 1 is a wiring diagram of the pressure responsive switch used as a safety device for protecting a starter motor
  • FIG. 2 is a sectional view showing the timelag pressure responsive switch according to this invention.
  • FIG. 3 is a section taken along the line III-Ill of FIG. 2.
  • the ignition key switch CC of an internal combustion engine controls on the one hand the distributor A and on the other hand a circuit comprising in series a front contact CF actuated by the selector lever L of the change speed transmission, the back contact CO ofa pressure responsive switch MC and a relay R controlling in turn a contact CR inserted in the circuit for energizing the starter motor CD.
  • the ignition contact is not closed (i.e. when the ignition key switch remains open);
  • the engine rotation causes the pressure of the engine lubricating oil or of the hydraulic circuit controlling the change speed transmission, or in a separate hydraulic transmission circuit, to actuate the pressure responsive switch MC to open the energizing circuit of relay R, thus preventing the energization of this relay and therefore of the starter motor when the engine is running.
  • a timelag pressure responsive switch is provided according to this invention in the above-described circuit.
  • FIG. 2 illustrates a typical constructional example of a timelag pressure responsive switch comprising a body 1 enclosing a pressure chamber 2 closed by a flexible diaphragm 3 secured by its outer peripheral or marginal portions to the body 1. This diaphragm 3 is urged, through the medium of a cup-shaped piston 4 by an antagonistic spring 5, towards a port 6 communicating with the proper fluid circuit.
  • the fluid under pressure for example the oil circulating in the lubricating system of the engine, flows into chamber 2 via said port 6 in which a push member 7 having an outer diameter slightly inferior to that of said port slidably mounted.
  • This push member projects into the chamber 2 and engages the diaphragm 3.
  • the lower portion of push member 7 constitutes a shank 8 formed with longitudinal peripheral channels or grooves 9 having the shape illustrated in cross-sectional view in FIG. 3.
  • the flexible diaphragm 3 is adapted to actuate a sliding control rod 10 solid with a movable contact bridge 11 urged by a spring 12 to a position in which it closes a pair of contacts 13, 14.
  • the timelag characteristic of the pressure responsive switch increases with the oil viscosity, thus increasing the time during which the starter motor assists the engine during its starting period in cold weather.
  • This pressure responsive switch operates as follows:
  • a timelag pressure responsive switch comprising a body having a pressure chamber and a port communicating with said chamber, a source of pressurized fluid connected to said port, a flexible diaphragm mounted in said chamber responsive to said pressurized fluid, spring means biasing said diaphragm against the pressure of said fluid, electrical contact means,
  • a time-lag pressure responsive switch according to claim 1 wherein the end of said push member remote from said diaphragm has at least one longitudinal groove having a total cross section considerably larger than the cross section of said annular passage.
  • a time-lag pressure responsive switch according to claim 1 further comprising a cup-shaped piston interposed between said diaphragm and said contact control means and transmits the displacement of said diaphragm to said contact control means.
  • a time-lag pressure responsive switch wherein said contact control means is spaced from said diaphragm a distance greater than the length of the smaller annular passage.
  • contact control means responsive to movement of said diaphragm to actuate said contact means, and timelag means to adjust the rate of delivery of said pressure fluid to said chamber for retarding the actuating of said switch means, said timelag mean s comprising a push member moving freely in said port under the pressure of said fluid, the inner diameter of said port being greater than the outer diameter of said push member forming an annular passage therebetween, said passage having a throttling effect reducing the rate of fluid delivery to said chamber, said contacts being actuated only after the conjugate pressures exerted by the fluid against said push member and said diaphragm have overcome the bias of said spring and said push member clears a considerably larger passage for said fluid to said chamber thus permitting rapid movement of the contact control member whereby the timelag characteristics increase with the fluid viscosity while preserving the snap opening ofsaid contact means.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
US789300A 1968-01-19 1969-01-06 Time-lag pressure responsive switches Expired - Lifetime US3588403A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR136766 1968-01-19

Publications (1)

Publication Number Publication Date
US3588403A true US3588403A (en) 1971-06-28

Family

ID=8644838

Family Applications (1)

Application Number Title Priority Date Filing Date
US789300A Expired - Lifetime US3588403A (en) 1968-01-19 1969-01-06 Time-lag pressure responsive switches

Country Status (3)

Country Link
US (1) US3588403A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE1901697A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR1566274A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711222A (en) * 1971-01-11 1973-01-16 E Hartley Pumping system
EP0036759A3 (en) * 1980-03-21 1982-04-21 Alan Cobham Engineering Limited Pressure responsive switch actuating mechanism

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2401266C2 (de) * 1974-01-11 1985-04-04 Berthold 6650 Homburg Brendel "Schaltgerät zum Anlassen und Abstellen eines Verbrennungsmotors"
DE4107413C2 (de) * 1991-03-08 1995-02-23 Hella Kg Hueck & Co Druckschalter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711222A (en) * 1971-01-11 1973-01-16 E Hartley Pumping system
EP0036759A3 (en) * 1980-03-21 1982-04-21 Alan Cobham Engineering Limited Pressure responsive switch actuating mechanism
US4435626A (en) 1980-03-21 1984-03-06 Alan Cobham Engineering Limited Pressure responsive switch actuating mechanism

Also Published As

Publication number Publication date
DE1901697A1 (de) 1970-02-05
FR1566274A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1969-05-09

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