US2654393A - Two phase electromagnetic device - Google Patents

Description

Oct. 6, 1953 E. I. GHORMLEY TWO PHASE ELECTROMAGNETIC DEVICE Filed July 24, 1948 H/J' ATTORNEY Patented Get. 6, 1953 TWO 'PH ASE ELECTROMAGNETIC DEVICE Edwin L 'Ghormley, Dayton, Ohio, assignor to "United Aircraft :Products, Inc., Dayton, Ohio,

:2. corporation-of Ohio npplieauonsuly-a i, 1948,'Serial No.'40;559

-301aims. 1

This :invention relates to -telectromagnetically :controlled devices and particularly to devices-oi that class wherein the core .of the 'electromagnet .has a relatively long travel, :as in following the motion of a related part.

Electromagnetic devices of the kind to which this invention pertains comprise :an energizable .coil and :a core or plunger :mo'vable in response to energizing of the c'oilito perform some iun'c- :tion, such as operating 'a valve or a-switc'h. The

core is movedinan'operating direction-by attrac tion set up by the coil and is returned and :held to .its starting position by a spring. When the required motion of the core is slight, n'o structural problems arise and the size of the coil and the overall dimensions of the device may :be relativelysmall. When aparti'cular installation necessitates a longer travel of the core, however, certain problems arise which have heretofore been metonly byincreasing the size and strength of the coil. Among these problems is the fact that an increase in thecore travel involvesad'ded return spring strength, and, moreover, multiplies the resistance or force rate of the spring. The coilmu'st therefore be made largeenough to overcome the initialanddeveloped'iorceoi the spring. in installations wherein the spring further is used to return the valve, "switch or other part actuated, a relatively heavy spring 'is required and correspondinglygreater pow'ermustbe built "into the coil. Further a long core travel means that the magnetic attraction necessary to obtain initial 'motion of'the core is appliedaccross a long air gap. The force of attraction generated, therefore, must be increased'in some proportion to the lengtho'f th'egap.

It is an object of the present invention toime'et the problems above noted in a manner other than by adding to the power of the solenoid .rne'chanism. Related objects in this connection are, accordingly, to reduce the size and voltage of an electromagnet required to perform the'following and other functions involving ailo'ng core travel; to make such an 'electromagnet :more suitable for use in aircraitand like'installations where smallness of size and lightness of weight are paramount'considerations; and to present a generally new solenoid mechanism, simple 'and'in'expensive of construction and characterized by reliable and efiicient operation.

Another object-of the invention is to introduce a new principle of operation in solenoid mech anisms wherein development and increase or the return spring force is eliminated over the major part of the Working stroke of the core.

Afurther object :is to obviate the need for applying magnetic attraction across .a long gap in solenoids providing a long core travel. Still another object is to eliminate the return spring force in a solenoid mechanism while retaining a moving iorcein the direction of movement desired.

In carrying out the above objects there has been evolved an electro-"nagnetic mechanism characterized by atWo 'part core unit, the op- 'eration'of the mechanism taking place in a'first phase wherein the core elements move relative to one another to overcome the return spring force and to initiate motion of the part controlled, and in a second phase wherein the core elements move as a unit to follow the motion of the part controlled without further opposition from the return spring.

Other objectsand structural details oi the .invention will appear from the following :descrip- 'tion when read in connection with the accompanying drawing, which is 'a view in longitudinal section of a solenoid controlled valve embodying the present invention.

Referring to the drawing, the invention is :discl'osed as embodied in a solenoid "controlled, pressure'fluid operated valve for use in the hydraulio and fuel systems of aircraft -.and like in- 'stallations.

The valve comprises a body it closed at its iiiiier'orright hand-endand formed with a central bore H. A series of radial ports 12 are formed inthebo'dy ltadja'cent the left hand or outer end-thereorand communicate with bore 11. The ports 12 provide access to the bore H for fluid flowing under pressure in a passage (not shown) registering with the ports i2. The valve device, as shown, is designed to be inserted as a unit or package into 'a pump housing or the he, the body being externally threaded at 3 for connection with the housing.

Recipro'cable within the bore ii is a piston assembly 20 comprising a piston it connected 7:33 a stem of reduced diameter to a valve head it situated immediately outside the left hand end of th'e'body ll]. Valve 15 abuts against a ring It which surroundsthe open end of bore l i and provides a seat for the valve. The valve it urged to a seat upon "ring it, in which position it closes on" or prevents fluid flow out of the open end of bore 11, loy a spring ifl contained in a housing IB securedt'o the end of body it. Housing 'l"8-'cornmunicates with a passage (.not shown) of low pressure relative to the passage supplying ports l2. Intermediate the piston it and valve 15 the piston assembly 25 is formed with a flute-d guide or bearing member l9. Extending longitudinally through the piston assembly is a bore 2! constituting a fluid passage through the assembly. Within the inner or right hand end of piston i4 is a counterbore 22, into the bottom of which opens passage 2|.

In the closed position of valve i5, the valve and piston i l present approximately equal opposing areas to the pressure fluid admitted to bore H by way of ports i2. The piston assembly 25 accordingly normally is balanced and the spring ii is effective to maintain the parts in the positions indicated. The piston 15 has a loose fit in the bore I in such manner that fluid within the bore may flow past the piston to the closed end of bore H, which end thus becomes a pressure chamber designated at 23. Fluid within pressure chamber 23 normally may escape therefrom to the low pressure area through the longitudinal passage 2| so that no opportunity is aflorded for the pressure in chamber 25 to rise sufflciently to overcome spring I2 and open valve i5. Should passage 2| be closed, however, the pressure in chamber 23 will rise and be effective to move the piston assembly in a direction to open valve i5. In that position of the parts the pressure fluid admitted to bore ii through ports i2 is free to pass out of the bore around valve 55 to a place of discharge in the system. Then should passage 2! again be opened, the pressure in chamber 23. will be relieved and the fluid pressures acting upon the piston assembly will again come into balance whereupon the spring ll may restore the parts to their starting position.

The passage 2| is controlled by a needle valve 22 reciprocable within counterbore 22 into and out of a seated position within passage 2|. The needle valve 22 is formed on one end of a push rod 25 extending through pressure chamber 23 and out of the inner end of body It by way of a central opening 26 therein. Push rod 25 is surrounded for a part of its length by a cylindrical cage or housing 21 received in counterbore 22 of piston i l. The housing 21 has a slight clearance relatively to the side walls of counterbore 22 and abuts the bottom of the counterbore, the inner end of the housing having a central opening 28 through which the valve 24 projects toward passage 2 end of housing 21 place passage 2| in communication with counterbore 22. The push rod 25 has a collar 3| thereon near the valve 22. A compression spring 32 surrounds valve 24 and is interposed between the closed end of housing 2? and collar 3 The spring thus is effective to urge the push rod 25 and valve 24 thereon outward or in a direction normally to hold the valve in an open position relatively to passage 2 I.

The construction and arrangement is such as to permit a free flow of fluid from pressure chamber 23 to passage 2| while the valve 24 is open and to prevent such flow when the valve 24 is closed. Closure of valve 24 is brought about by an axial motion of push rod 25 in a left hand direction as viewed in the drawing against the resistance of spring 32. When the axial closing pressure applied to rod 25 is removed, the spring 32 is enabled to return the rod in the opposite direction whereby to move valve 24 out of its seat in passage 2| and reestablish communication between the passage and pressure chamber 23.

The push rod 25 extends through opening 25 in body I into cooperative relation with the solenoid mechanism. This mechanism comprises a Radial slots (not shown) in the lower 1 housing 33 one end of which is turned over upon a flange 34 on the body If] and the other end of which has a lapped connection with a cap 35. The cap 35 provides a mounting for a connector 36 through which electrical leads 3i are introduced into the housing. The electrical leads 5'! are operatively connected to a cylindrical, energizable coil 1-28 wound upon a spool assembly comprising a plate 39, a tube 4! and the end of body element It. The tube ll is received at its inner or left hand end in the opening 25 in body It and opens at that end into pressure chamber 23. At its opposite end the tube 4| projects through and beyond plate 39 and is closed at that end.

The tube ll provides a bore for the reciprocation of a core movable therein in response to the electromagnetic attraction set up by coil 38. The core of the solenoid mechanism comprises a first or rearward plunger element 42 and a second or forward plunger'element 43. The plunger elements 42 and 43 are axially aligned and normally are separated by a slight gap id. Forward plunger element as has a longitudinal opening 45 therein through which the push rod 25 is passed, the outer or right hand end of the rod abutting element 42 and normally holding it in the outer end of tube ll as indicated. The inner or left hand end of plunger element 43 is reduced in diameter and has a press fit with the aforementioned housing 21. Housing 21 thus is in effect rigidly connected to plunger element 63 which accordingly is limited and controlled in its movement by piston M. This construction and arrangement of parts, in cooperation with the spring pressure exerted by rod 25 upon plunger element 22 serves to define the gap 24 between the plunger elements. The plunger elements 22 and 33 are offset relatively to the horizontal center plane of the coil 38, and their mounting and the size of coil 38 are such as to provide for a relatively long travel of the core within the coil.

When the coil 38 is energized the initial result is to effect a motion of plunger 42 relative to plunger element as to close the gap 245. In the course of such movement, push rod 25 is moved axially leftward and passage 2| in the piston assembly 28 is closed by valve 22. The fluid pressure in chamber 23 quickly rises in consequence of the closing of passage 2|, and the piston assembly moves leftward to open valve l5. Coil 38 remains energized during this period, and, as the piston it moves leftward in bore the plunger elements 32 and 43 also move leftward as a unit to maintain valve 22 in its seated position in passage 2l. This motion is accomplished without additional resistance from the spring 32 since the spring and its cage or housing 27 move with the core elements 22 and 43. As long as the coil 38 continues energized, the parts will remain as above described and fluid flow occurs in the valve through ports i2 and bore past valve i5 to the low pressure area communicating with housing l3. When the solenoid coil 28 is de-energized, spring :32 is effective to move push rod 25 outwardly or in a right hand direction as viewed in the drawing and in so acting moves valve 25 out of its seat in passage 2| or to open position. With valve 24 open the pressure in chamber 23 is relieved through passage 2| and the piston assembly is returned in a direction to close valve i5 by spring H as previously described. The return motion of piston I2 together with expansion of spring 32 efiects a return of the plunger elements 42 and 43 to the starting positions shown in the drawing.

It will be understood that the invention has a scope unlimited by specific details of the illustrative embodiment thereof and that it is susceptible of uses and adaptations other than in the fluid pressure operated valve in connection with which it is here disclosed.

What is claimed is:

1. In an electromagnetic device, a housing, a cylindrical energizable coil in said housing, a two part metallic core reciprocable within said coil, said coil and said core being so arranged as to provide a relatively long travel of said core within said coil, said core being made up of axially aligned forward and rearward magnetic core elements, a forwardly extending tubular cage rigidly connected to the forward one of said core elements, a push rod having its one end within said cage and extending through said forward core element into contact with the rearward one of said core elements at its other end, a compression spring seated within the forward end of said cage and urging said push rod toward contact with the rearward one of said core elements, and movable means providing a positioning support for said cage and said forward core element, said movable means and said compression spring cooperating normally to define a relatively slight gap between said core elements, the energizing of said coil serving initially to close said gap and to overcome said spring, and serving subsequently to move said core elements as a unit under the control of said movable means.

2. An electromagnetically controlled valve device, comprising a body, a piston bore in said body, a piston in said bore, means for admitting pressure fluid to said bore to move said piston, a passage through said piston for the escape of pressure fluid from said bore, a valve reciprocable to open and close said passage, a spring urging said valve in a direction to open said passage, a housing for said spring limiting against said piston, a rod-like extension on said valve projecting axially through said spring housing, an energizable solenoid coil surrounding said extension, a two-part core reciprocable within said coil, said core comprising forward and rearward elements axially aligned and normally spaced from one another, said forward element being rigidly connected to said spring housing, and an opening in the forward core element through which said rod-like extension passes into contact with the rearward core element, the energizing of said solenoid coil serving initially to close the space between said core elements whereby to move said valve against the urging of said spring to close said passage, subsequent motion of said piston being followed by said core elements as a unit to maintain said passage closed.

3. An electromagnetically controlled valve device, comprising a body, a piston bore in said body, a piston in said bore, a longitudinal fluid passage through said piston, a valve reciprocable in opposite directions to open and close said passage, a spring urging said valve in one of said directions, a housing for said spring limiting against said piston, a rod-like extension on said valve projecting axially through said spring housing, an energizable solenoid coil surrounding said extension, a two-part core reciprocable within said coil and comprising forward and rearward core elements axially aligned and normally spaced apart, said forward element being rigidly connected to said spring housing, and an opening in the forward core element through which said rod-like valve extension passes into contact with the rearward core element.

EDWIN I. GHORMLEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 587,786 Brown Aug. 10, 1897 604,358 Alexander May 24, 1898 792,076 Read June 13, 1905 926,389 Collin June 29, 1909 1,175,864 Gold Mar. 14, 1916 1,293,697 Canfield Feb. 11, 1919 1,452,859 Wichser Apr. 24, 1923 1,460,517 Stevens July 3, 1923 1,579,049 Ainsworth Mar. 30, 1926 2,117,726 Johnson May 17, 1938 2,131,942 Evans Oct. 4, 1938 2,319,578 Beekley May 18, 1943 2,373,256 Miller Apr. 10, 1945 2,379,181 Pontius June 26, 1945 2,496,553 Littlefield Feb. 7. 1950

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