US2335073A - Pressure actuated switch - Google Patents

Pressure actuated switch Download PDF

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Publication number
US2335073A
US2335073A US371868A US37186840A US2335073A US 2335073 A US2335073 A US 2335073A US 371868 A US371868 A US 371868A US 37186840 A US37186840 A US 37186840A US 2335073 A US2335073 A US 2335073A
Authority
US
United States
Prior art keywords
switch
casing
pressure
bore
chamber
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
US371868A
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English (en)
Inventor
Martin Erle
Thomas E Doherty
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.)
RTX Corp
Original Assignee
United Aircraft Corp
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 United Aircraft Corp filed Critical United Aircraft Corp
Priority to US371868A priority Critical patent/US2335073A/en
Priority to GB117/42A priority patent/GB553583A/en
Application granted granted Critical
Publication of US2335073A publication Critical patent/US2335073A/en
Priority to FR930787D priority patent/FR930787A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/30—Blade pitch-changing mechanisms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/30—Blade pitch-changing mechanisms
    • B64C11/301—Blade pitch-changing mechanisms characterised by blade position indicating means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/30—Blade pitch-changing mechanisms
    • B64C11/38—Blade pitch-changing mechanisms fluid, e.g. hydraulic
    • B64C11/42—Blade pitch-changing mechanisms fluid, e.g. hydraulic non-automatic
    • 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
    • H01H35/38—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by piston and cylinder

Definitions

  • This invention relates to improvements in hydraulic control devices and has particular reference to an improved control unit for a hydrocontrollable feathering-type propeller.
  • An object of the invention resides in the cornbination of an improved pressure actuated electric switch for discontinuing the application of pressure to a hydraulic mechanism when the pressure has reached a predetermined value.
  • a further object resides in the ⁇ provision of ai# 10 improved pressure actuated switch of the character indicated which is responsive to a difference in the inlet and exhaust pressures of a hydraulic mechanism such as a propeller pitch changing mechanism.
  • a still further object resides inthe provlsionl-' of an improved pressure actuated switch' of the character indicated which may be connected into a hydraulic circuit without danger of leakage of hydraulic fluid through or from the switch mechanism and in which the switch contact points are immersed in hydraulic fluid which tends to damp any tendency of the electric current to arc at the contact points.
  • Fig. 1 is a schematic partly sectional view of a hydro-controllable feathering-type propeller.
  • Fig. 2 is a schematic view of the control apparatus for such a propeller schematically illustrating the manner in which a pressure actuated switch such as that constituting the invention is incorporated therein.
  • Fig. 3 is a detailed sectional view on an enlarged scale of a pressure actuated switch constructed according to the invention, the switch being shown in operative position with respect to a member of the control apparatus through whichfiuid conduits extend, and
  • the numeral I 0 generally indicates a propeller driving shaft projecting from an engine generally indicated at I2 and carrying a hydro-controllable featheringtype propeller generally indicated at I4.
  • This propeller may be of the type particularly illustrated and described in my co-pending United States application Serial No. 184,792, filed January 13, 1938, for Feathering propeller control, and may have a hub I6 carrying a plurality of blades, one of which is indicated at I8, rotatably mounted therein for pitch changing movements.
  • Each blade may be provided with a gear member 2
  • the cam 24 may be rotated by means of a piston 28 reciprocable in a relatively fixed cylinder 30 and carrying cam followers as particularly illustrated andV described in ⁇ United-States application Serial No. 184,792, re-
  • Fig. 4 is a detailed sectional view on an enlarged to a valve generally indicated at 42 which, when subjected to pressures below a predetermined limit, connects the passage 32 with the interior of the cylinder 30 at the pitch increasing side of the piston 28 and connects the passage 38 with the interior of the cylinder 30 at the pitch decreasing side of the piston. This position of the valve 42 is shown in Fig. 1.
  • a passage 52 leads to the engine lubricating system and a passage 54 leads to the governor 46.
  • This governor may include a booster pump and a governor actuated valve disposed between the outlet of the booster pump and the passage 34 which construction is particularly illustrated and described in United States Patent No. 2,204,640, issued June 18; 1940, to Elmer E. Woodward for Governor mechanism.
  • the pitch changing mechanism is provided with some form of intermediate pitch limit stop which will prevent the mechanism from turning the blades beyond a predetermined high pitch position when actuated by hydraulic fluid at the pressure supplied by said governor booster pump to keep the pitch within the range of constant speed control.
  • a motor 56 is energized to drive a high pressure pump 58 the outlet of which is connected through a channel E0 with a valve 62 which acts, when subjected to high pressure fluid from the pump 58 to block olf the governor outlet channel 64 and connect the channel 34 directly with the outlet of the pump 58 to supply hydraulic fluid at the increased pressure, sufficient to override the intermediate pitch limit stop mentioned above, to the space within the cylinder 30 at the pitch increasing side of the piston 28 to rotate the propeller blades to their limiting high pitch or feathered position.
  • Energization of the motor 56 is controlled by a relay switch 66 interposed in the circuit between the motor and the source of power such as the battery 68.
  • This relay switch is urged toward its open position by a spring 'l0 and is closed by a solenoid 12 the energization of which is controlled by a manually operable switch 14.
  • Switch 14 is urged toward its open position by a spring 16 and retained in closed position by a solenoid 18 the energizing circuit of which includes the pressure operatedrswitch 80 hydraulically connected with the channel 60 in such a manner that fluid pressure in the channel 60 at a predetermined value will open this switch.
  • Opening of switch 80 de-energizes the solenoid 18 and permits switch 14 to open under the influence of the spring 16 thus de-energizing the solenoid 12 and permitting the relay switch 66 to open under the influence of the spring 10. Opening of switch 86 de-energizes the motor B and stops the pump 58.
  • the predetermined pressure value selected is a value slightly above the maximum required to turn the propeller blades in a pitch increasing direction between intermediate high pitch position and feathering position indicating that the propeller has reached its full feathered condition.
  • This arrangement causes the pressure actuated cut-out switch to operate on the difierence between the pressure of the fluid supplied to the pitch increasing side of the pitch changing mechanism and the pressure of the fluid vented from the pitch decreasing side of the mechanism when the propeller is brought to its feathered position which arrangement gives a more sensitive action of the switch and insures that the propeller will have reached a fully feathered condition before the feathering circuit is broken by the switch 80.
  • switch shown in Fig. 2 is of the same form as the switch shown in Fig. 3 which has been generally designated by l,the numeral 80 while the somewhat modified form of switch shown in Fig. 4 is generally designated by the numeral 80.
  • the switch B0 comprises a casing 82 which may be conveniently formed as a metal casting or forging.
  • This casing has a flat plate 84 for cooperation with the flat face of a pad 86 to which the switch is attached, a gasket 88 being preferably included between the switch and the pad to prevent leakage of fluid through this joint.
  • the pad B6 is formed integrally with some portion of the control apparatus, for example with the base or pad 90 of the governor 40 and the switch is secured to the pad by suitable means such as the screws 92.
  • Within the casing B2 there is a cylindrical bore 94 having a reduced cylindrical extension 96 at one end thereof the end of which is closed by the wall of the casing and having an internally screw threaded portion 58 at the opposite open end thereof.
  • 00 is molded onto a plunger'
  • 02 carries a contact portion
  • 06 is secured in the closed end of the extension 94 in position to cooperate with the contact member
  • 02 projects into the chamber
  • 20 is provided with an externally threaded portion which cooperates with the threaded portion 98 of the bore 94 and with a shoulder
  • the channel lv leads into thechamber iii! and the channel t is led to the space at the closed end of the cylindrical extension 96 ol the bore 94 which space contains the contact
  • 00 is preierably ⁇ formed of insulating material.
  • thermo-setting phenolic condensate such as a thermo-setting phenolic condensate and is dimensioned to provide a positive clearance between itself and the wall of the/bore 96 so that a small quantity of the i'iuidiorced under pressure into the space between the inner end of this bushing and the closed end of the bore will pass into the chamber
  • 0 beed by the larger bore S4, and into the drain channel 8
  • 4 is sufficiently resilient to permit separation of the contact members .
  • 28 is substantially the same as the casing 82 of the switch shown in Fig. 3 and has an internal bore
  • At the open end of the bore casing is provided with a cylindrical extension i.
  • This terminal member is provided with an internal shoulder
  • 40 is dispo-sed within the cylindrical portion
  • 32 contains a resilient bushing
  • 50 extends between suitable abutments carried respectively by the members H8 and-
  • 52 leads to the space containing the contact members
  • the switches shown in Figs. 3 and 4 both operate in the same manner, the structural dierences shown in these two embodiments of the invention being mainly important from a manu-
  • 22 is molded into the terminal member
  • 22 is molded into the terminal member
  • 40 can be made separately and thereafter the connecting plug
  • 8 do not have to be incorporated in the structure during the molding or vulcanizing process and these various units can be brought together and assembled by the manufacturer or user of the switch.
  • a switch comprising a casing having a chamber therein and a counterbore of smaller diameter than said chamber extending from said chamber to adjacent one end of said casing, a fixed contact member extending through said casing into the closed end of said counterbore, a bushing of insulating material separating the closed end of said counterbore from'said chamber, a movable contact member mounted in said bushing and extending into said counterbore, resilient electrical conducting means urging said movable contact member into contact with said fixed contact member and forming a part of the circuit controlled by said switch, and a passage in said casing opening into said counterbore at the closed end thereof to admit fluid under pressure to said counterbore at the side of said bushing opposite said resilient means to open said contact.
  • a hollow casing, movable means comprising an electrical contact member and an insulating bushing therefor dividing the interior of said casing into two separate chambers, respective fluid channels leading to said chambers, and a fixed contact member in one of said chambers in electrical contact with said casing and cooperating with said movable contact member to make and break an electrical circuit including said switch, an electrical connector insulatedly carried at one end of said chamber, and a spring urging said contact'l members together and constituting the sole electrical connection between said connector and said movable contact.
  • a fluid pressure actuated electric switch comprising, a unitary casing adapted to be mounted on a machine surface and having at one side thereof a fiat external surf ace and interiorally thereof a bore open at one end and closed at the opposite end and providing tandem pressure chambers, and fluid passages extending one from each pressure chamber and opening to said flat surface, a, fixed contact member mounted in said casing at the closed end of said bore, an insulating bushing slidable in said bore between said fluid passages, and a movable contact member carried by and extending through said bushing.
  • a fluid pressure actuated electric switch comprising, a unitary casing adapted to be mounted on a machine surface and having at one side thereof a flat external surface and interiorly thereof a bore open at one end and closed at the opposite end and providing tandem pressure chambers, and fluid passages extending one from each pressure chamber and opening to said flat surface, a fixed contact member mounted in said casing at the closed end of said bore, an insulating bushing slidable' in said bore between said fiuid passages, and a movable contact member carried by and extending through said bushlng, said contact members constituting 'a stop for said busihng to restrain said bushing from covering the end of one of said fluid passages.
  • a unitary casing comprising a flat plate base portion having a fiat surface, and a cylindrical portion extending across said base portion and provided with an internal bore the axis of which is substantially parallel to said fiat surface and which is closed at one end by the casing wall, a fixed contact member secured in said casing, a plunger in said bore separating said bore into two fluidV chambers each connected through a respective fluid channel with the face surface of said base portion, and a movable contact member carried by said plunger.
  • a unitary casing comprising -a base portion having a fiat face surface, and a chamber portion having a bore the axis of which is substantially parallel to said face surface and which is closed at one end by a wall of said-casing, a fixed contact member carried by said casing at one end of said bore, means including a movable contact member dividing said bore into separate pressure chambers each connected through a respective fiuid channel with said flat face surface, and a current conducting spring in said bore resiliently urging said movable contact member toward said fixed'contact member.
  • a casing having a high pressure chamber and a low pressure chamber and an intercommunicating cylinder wall therebetween, a fixed contact in said high pressure chamber, an insulated piston slidable in said cylinder wall and carrying a movable contact, and a spring in said low pressure chamber electrically connected to said movable contact and urging the same into engagement with said fixed contact, said piston being smaller than said cylinder wall and having a clearance to permit passage of oil from said high pressure chamber around and past said piston to said low pressure chamber.
  • a casing having a high pressure chamber and a low pressure chamber and an intercommunicating cylinder wall therebetween, a fixed contact in said high pressure chamber, an insulated piston slidable in said cylinder wall and carrying a movable contact, and a spring in said low pressure chamber urging said piston toward said fixed contact to maintain said movable contact in engagement therewith, said casing having a passage connected with an actuating system and said high pressure chamber for admitting high pressure oil from the actuating system to said high pressure chamber and another passage connected with said actuating system and said low pressure chamber Vfor returning oil from said low pressure chamber to the actuating system, and said piston being smaller than said cylinder wall and having a clearance for the passage of oil from said high pressure chamber to said low pressure chamber.
  • a casing having a high pressure chamber and a low pressure chamber, a fixed contact in said high pressure chamber, an insulated piston subject to said high pressure and carrying a movable contact, a spring in said low pressure chamber electrically connected to said movable contact and urging the same into engagement with said fixed contact, said low pressure chamber having an insulated wall, and a terminal carried by said wall forming a seat and a guide for said spring and forming a stop for said movable contact.
  • a metal casing having a rst bore and a smaller bore extending therebeyond, a fixed contact grounded in said smaller bore, an insulated piston slidable in said smaller bore and carrying a movable contact having a head extending into said first bore, an insulated plug closing said first bore and supporting a terminal stem having a head extending into said first bore, and a. coiled compression metal spring surrounding said terminal head and seated thereon and bearing against the head of said movable contact.
  • a switch forming a portion of a liquid system and comprising a casing having a pressure chamber therein, a fixed contact member extending into said chamber, a second chamber in said casing, a slidable bushing of insulating material separating said chambers and having a. contact member mounted therein and extending into the chamber containing said xed contact, said bushing having clearance in said casing to provide a restricted connection between said chambers, means to admit liquid under pressure from said liquid system to said chamber containing said fixed contact to open said contacts, and means for conducting liquid from said second chamber to said liquid system, some of said liquid under pressure moving through said restricted connection from the contact chamber to said second chamber to prevent an accumulation of sludge and congealing of liquid in said contact chamber.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Measuring Fluid Pressure (AREA)
US371868A 1940-12-27 1940-12-27 Pressure actuated switch Expired - Lifetime US2335073A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US371868A US2335073A (en) 1940-12-27 1940-12-27 Pressure actuated switch
GB117/42A GB553583A (en) 1940-12-27 1942-01-03 Improvements in or relating to pressure actuated electric switches
FR930787D FR930787A (fr) 1940-12-27 1946-07-18 Perfectionnements aux dispositifs contacteurs actionnés par pression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US371868A US2335073A (en) 1940-12-27 1940-12-27 Pressure actuated switch

Publications (1)

Publication Number Publication Date
US2335073A true US2335073A (en) 1943-11-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
US371868A Expired - Lifetime US2335073A (en) 1940-12-27 1940-12-27 Pressure actuated switch

Country Status (3)

Country Link
US (1) US2335073A (fr)
FR (1) FR930787A (fr)
GB (1) GB553583A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431674A (en) * 1941-04-03 1947-12-02 Honeywell Regulator Co Differential pressure switch
US2604561A (en) * 1948-11-22 1952-07-22 Joseph M Simon Pressure differential switch
US3060290A (en) * 1959-05-04 1962-10-23 Gen Motors Corp Time delay switch
US3118986A (en) * 1962-04-23 1964-01-21 Henry W Lewis Explosive actuated circuit breaker
US3246707A (en) * 1964-02-17 1966-04-19 Schlumberger Well Surv Corp Selective firing system
US3508236A (en) * 1967-03-28 1970-04-21 Robert H Adams Fluid pressure system warning device
EP0883147A3 (fr) * 1997-06-03 1999-08-11 Vimatic S.r.l. Interrupteur différentiel hydraulique ou pneumatique

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5225641A (en) * 1992-06-24 1993-07-06 Allied-Signal Inc. Fluid flow switch assembly
US6635836B1 (en) 2002-04-18 2003-10-21 Oil-Rite Corporation Housing contained fluid flow switch and indicator

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431674A (en) * 1941-04-03 1947-12-02 Honeywell Regulator Co Differential pressure switch
US2604561A (en) * 1948-11-22 1952-07-22 Joseph M Simon Pressure differential switch
US3060290A (en) * 1959-05-04 1962-10-23 Gen Motors Corp Time delay switch
US3118986A (en) * 1962-04-23 1964-01-21 Henry W Lewis Explosive actuated circuit breaker
US3246707A (en) * 1964-02-17 1966-04-19 Schlumberger Well Surv Corp Selective firing system
US3508236A (en) * 1967-03-28 1970-04-21 Robert H Adams Fluid pressure system warning device
EP0883147A3 (fr) * 1997-06-03 1999-08-11 Vimatic S.r.l. Interrupteur différentiel hydraulique ou pneumatique

Also Published As

Publication number Publication date
GB553583A (en) 1943-05-27
FR930787A (fr) 1948-02-04

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