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US3557329A - Pressure responsive switch - Google Patents

Pressure responsive switch Download PDF

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Publication number
US3557329A
US3557329A US807835A US3557329DA US3557329A US 3557329 A US3557329 A US 3557329A US 807835 A US807835 A US 807835A US 3557329D A US3557329D A US 3557329DA US 3557329 A US3557329 A US 3557329A
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US
United States
Prior art keywords
pressure
passage
flexure beam
actuator
diaphragm
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
US807835A
Other languages
English (en)
Inventor
Joseph E Gorgens
Randall Goff
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.)
Dresser Industries Inc
Original Assignee
Dresser Industries Inc
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 Dresser Industries Inc filed Critical Dresser Industries Inc
Application granted granted Critical
Publication of US3557329A publication Critical patent/US3557329A/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
    • 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

Definitions

  • ABSTRACT A pressure operable electrical switch having a diagonally supported flexure beam interposed between a pressure responsive diaphragm and a ball movable against a switch actuator.
  • An exposed adjusting knob permits presetting pressure at which the instrument is to be operative and is located laterally displaced from the ball operatively connected to prevent beam movement at pressures below the setting thereof.
  • Condition responsive switches for various control purposes are well known in the industry and available from many sources of manufacture. While commercially available pressure actuated switches are known to function well, they are generally characterized by insufficient compactness, i.e., having too great a height dimension to meet particular customer needs and/or the inability to be adjustably and conveniently field set to the pressure at which the instrument is to be operative. Although many switches currently marketed contain one or the other of these features, none by virtue of their particu-Char construction are readily capable of combining both features within a single instrument in an economic manner enabling the product to favorably compete in present markets against similar devices having one or the other of these features.
  • Typical of the prior art are pressure switches such as those disclosed for example in U.S. Pat. Nos. 2,249,208; 2,722,580; 2,807,686; and 2,919,321. It can be seen from a review of the mechanisms in the devices of these prior patents, that their relatively sophisticated constructions are not amenable to competitively low fabrication cost to provide a low height, compact pressure switching unit having integral means enabling field adjustable presetting of the pressure operating point.
  • This invention relates to control instruments and particularly to pressure responsive electrical switch devices for operating a control circuit of external equipment or the like. More specifically, the invention relates to a pressure responsive control switch characterized by a highly compact assembly affording a minimum instrument height yet having the capability of convenient field set adjustability of the instrument for accurately effecting the set pressure at which the in strument is to be operative. Not only are both of these features readily and compactlycombined into a single instrument, but this result is achieved with a design affording high vibration resistance, low friction operation as to minimize inherent error as otherwise occurs in instruments of this type. Moreover, the simple construction hereof enables low production cost permitting the instrument to compete favorably in the market place against instruments marketed by others without these combined features.
  • the switch hereof can conveniently be constructed within an overall height of about 3 inches having a maximum lateral dimension of about 2 36 inches. Accordingly, by means of the invention hereof, features characterizing prior devices of this type are substantially improved on by a novel construction not previously known and affording a relatively low cost product satisfying a long felt need in the industry.
  • FIG. I is an elevation view of the switch instrument hereof partly cut away to expose internal construction detail
  • FIG. 2 is top plan view of the switch instrument hereof
  • FIG. 3 is a sectional elevation taken substantially along the lines 3-3 of FIG. 2;
  • FIG. 4 is sectional elevation taken substantially along the lines 4-4 of FIG. 2.
  • the illustrated embodiment of the invention includes a housing 10 representing the lower part of the instrument and having a shank l l for connection to a system in which the instrument is to be employed.
  • the shank includes a male thread and a female thread at'2l enabling screw mounting to a well, bracket or other support on which the instrument is to be situated.
  • the housing enlarges to a hexagonal formation 12 on which to externally receive a wrench or the like used to install the instrument in place and in turn merging into an enlarged and squared cuplike formation 13 defining an internal recess 15.
  • Supported and secured via bolts 14, 45 and 50 superposed overlying the cup end of the housing in pressure tight relation is a top plate 16 being exteriorly coextensive therewith.
  • a fluid passage 20 having a defined central axis 25.
  • the passage extends upward to an annular shoulder 27 defining a coaxial bore 22 opening into the housing recess 15.
  • a suitable preassembled pressure sensitive unit which may be of a type disclosed in Gorgens, et al. US. Pat. No. 3,393,6 l 2 incorporated herein by reference. As more fully disclosed in the Gorgens et al.
  • the pressure unit includes a diaphragm 34 attached to the underside of a piston 23, a cylinder 24 circumferentially surrounding the piston and a spring 26 in the form of a symmetrical spidershaped metal element overlying the piston to resist movement thereof.
  • Cylinder 24 has an L-shaped cross section, the radially inward directed flange of which presents a flat seating surface 28 on which the piston can rest.
  • piston 23 is of two diameters, the larger being indicated at 30, and the smaller being indicated at 32. In radial dimension the piston and cylinder are closely situated but sufficiently spaced to permit axial movement of the former in a relatively friction-free relation.
  • a thin piston flange or rim 33 is staked and deformed over the inner spring ring to secure the spring and piston in a firmly clamped relation while the fluid impervious rubber diaphragm 34 is sea-led and clamped at its edges by an O-ring 36.
  • the piston and diaphragm are concomitantly urged in a vertical direction in response to pressure changes received at the fluid passage 20 being upwardly in response to increased pressure and downwardly in response to decreased pressure.
  • a spherical ball 38 freely supported within bore 39 of top plate 16.
  • the ball is normally seated in drilled recessed 40 on the topside of piston 23 to be movable conjointly therewith.
  • Bore 39 likewise has an axis extension coincident with axis 25 and is of a diameter providing radial clearance to the ball sufficient to permit frictionless axial movement thereof.
  • a flexure beam 44 Overlying the ball in normally force contact engagement therewith (see HO. 4) is a flexure beam 44 secured to top plate 16 at one end via bolt 45 and relatively free at its opposite end whereat it is formed with a central bore 46 and an upward-turned flange 47.
  • Received through the bore 46 is a centering bolt 50 extending axially upward parallel and displaced from axis 25 to threadedly support an adjusting knob 52 at its uppermost end.
  • the knob is formed at its underside with a counterbore 53 in which to receive a coil spring 54 loaded by compression against flange 47 as will be explained. In this arrangement the compressive force of spring 54 acting against the flexure beam resists upward movement of the ball imposed by pressure acting against the underside of diaphragm 34.
  • beam 44 is of a relatively firm inflexible strip material having a window 48 defining a hinge location and is initially supported without preloading.
  • the rate of spring 54 is matched to the beam arm deflection corresponding to scale travelfor pressure calibrations on scale 68. At zero load, the spring is in its natural uncompressed state with the beam barely contiguous to the ball without any preloading thereon.
  • the operating switch differential between on and off can be governed by appropriate selection of the spring rate. Preferably, a 2 and 3 percent differential is employed for l and amperage service respectively.
  • switch unit 57 having a switch actuator in the form of a vertical plunger or pin 56 downwardly depending into engagement against the topside surface of beam 44.
  • Pin 56 is supported in axial alignment with axis 25, and endures vertical movement in a follower relation to beam 44.
  • the switch is of a suitable type commercially available for either line voltage or control line voltage having terminals 58, 59 and 60 to receive wire leads of the circuit in which it is to be connected.
  • a vertical bracket 62 having horizontally extending opposite ends 63 received beneath the nut of each bolt 14.
  • bracket 62 On the opposite face of switch 57 bracket 62 forms a nameplate 65 bent into a springlike engagement against the knurled surface of knob 52. This serves to provide a frictional detent against the knob whereby inadvertent resetting of the latter from vibration or the like is prevented.
  • the unit is comprised of a minimum number of operating components in which pressure received in the fluid passage 20 acts via the piston 23 in a linearly direct axially aligned movement against the switch actuator 56.
  • the switch is of a highly economical construction affording the combined features of minimal height and convenient field setting adjustment of the appropriate pressure at which theunit is to be operative.
  • a pressure responsive device comprising:
  • a housing having a central passage extending from a first end for connecting to a source of inlet pressure
  • movable means having one side operably engaging said diaphragm to be movable in direct response to yielding thereof and another side having a recess located in direct alignment with the axis of said passage;
  • control means operative by an actuator movable in axial alignment with the axis of said'passage
  • a pivotal flexure beam secured at one end and relatively free at the other end, said beam extending contiguously between said ball member and actuator and responsive to movement of said ball member to move said actuator between operative and inoperative position for said control means;
  • adjustment means to preset the operating pressure of said control means including means to apply a preset biasing force against the free end of said flexure beam acting in a direction to oppose pressure in said passage being exerted against said diaphragm.
  • a pressure responsive device in which said adjustment means is located axially displaced from said adjustment means is located axially displaced from said central passage and acts in a direction extending axially parallel thereto.
  • a pressure responsive device in which said adjustment means includes a coil spring acting against the free end of said flexure beam and a control knob threadedly mounted to compress the spring against said flexure beam.
  • a pressure responsive device including pressure unit calibrated indicia means correlated with a reference location on said control knob enabling visual observation of the set condition as the knob is threadedly advanced toward and away from said flexure beam.
  • a pressure responsive device in which said control means comprises an electrical switch having contacts for connecting to a circuit to be controlled.
  • control means operative by an actuator movable in axial alignment with the axis ofsaid passage
  • a pivotable flexure beam secured at one end and relatively free at the other end, said beam extending contiguously between said ball member and actuator and responsive to movement of said ball member to move said actuator between operative and inoperative positions for said control means;
  • adjustment means to preset the operating pressure of said control means including means to apply a preset biasing force against the free end of said flexure beam acting in a direction to oppose pressure in said passage being exerted against said diaphragm.
  • said adjustment means includes a coil spring acting against the free end of said flexure beam and a control knob threadedly mounted to compress the spring against said flexure beam.
  • control means comprises an electrical switch having contacts for connecting to a circuit to be controlled.
  • I Claim 2 line 63 delete "adj ustment means is located axially displaced from said" Signed and sealed this 2nd day of November 1971.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
US807835A 1969-03-17 1969-03-17 Pressure responsive switch Expired - Lifetime US3557329A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US80783569A 1969-03-17 1969-03-17

Publications (1)

Publication Number Publication Date
US3557329A true US3557329A (en) 1971-01-19

Family

ID=25197268

Family Applications (1)

Application Number Title Priority Date Filing Date
US807835A Expired - Lifetime US3557329A (en) 1969-03-17 1969-03-17 Pressure responsive switch

Country Status (4)

Country Link
US (1) US3557329A (nl)
BR (1) BR7017494D0 (nl)
GB (1) GB1259411A (nl)
NL (1) NL164996C (nl)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657501A (en) * 1970-11-23 1972-04-18 W E Anderson Inc Pressure actuated device with concentric piston stem actuators
US3789171A (en) * 1971-08-24 1974-01-29 Actuated Controls Ltd Pressure switch with operating lever having manually adjustable pre-loading means therefore
FR2566172A1 (fr) * 1984-06-14 1985-12-20 Honda Motor Co Ltd Interrupteur manometrique perfectionne

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3419693A (en) * 1965-05-31 1968-12-31 Clifford Edwards Ltd Control switch for a fluid pressure system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3419693A (en) * 1965-05-31 1968-12-31 Clifford Edwards Ltd Control switch for a fluid pressure system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657501A (en) * 1970-11-23 1972-04-18 W E Anderson Inc Pressure actuated device with concentric piston stem actuators
US3789171A (en) * 1971-08-24 1974-01-29 Actuated Controls Ltd Pressure switch with operating lever having manually adjustable pre-loading means therefore
FR2566172A1 (fr) * 1984-06-14 1985-12-20 Honda Motor Co Ltd Interrupteur manometrique perfectionne

Also Published As

Publication number Publication date
NL7003783A (nl) 1970-09-21
NL164996C (nl) 1981-02-16
GB1259411A (nl) 1972-01-05
BR7017494D0 (pt) 1973-01-16
NL164996B (nl) 1980-09-15

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