US2833508A - Electromagnetic control device - Google Patents

Description

y 6, 1953 Y F. J. BYDALEK ET AL 2,833,508

ELECTROMAGNETIC CONTROL DEVICE Filed Feb. 8, 1952 4 Sheets-Sheet 1 I INVENTORS. f'lgg d TI dale/ n May 1953 F. J. BYDAL-EK ETAL 2,833,508

ELECTROMAGNETIC CONTROL DEVICE Filed Feb. 8. 1952 4 Sheets-Sheet 2 May 6, 1958 F. J. BYDALEK ETAL 2,833,503

ELECTROMAGNETIC CONTROL DEVICE Filed Feb; 8. 1952 4 Sheets-Sheet :5

J INVENTORS:

E0 62 1/. B dale/ 1 Wigs:

F. J. BYDALEK ET AL 1,833,508

ELECTROMAGNETIC CONTROL DEVICE May 6, 1958 4 Sheets-Sheet 4 Filed Feb- 1952 I Q Q @wg 6 \Q m m 3% 2 w m United States Patent ELECTROMAGNETIC CONTROL DEVICE Floyd J. Bydalek and Russell B. Matthews, Milwaukee,

Wis.', assignors to Baso Inc., Milwaukee, Win, a corporation of Wisconsin Application February 8, 1952, Serial No. 276,6.56

19 Claims. (Cl. Z51133) This invention relates, in general, to control devices, and more particularly to electromagnetic operators having particular utility in the operation of valves or the like of novel construction and coaction for controlling the flow of fluids therethrough.

One or" the main objects of the present invention is to provide an improved form of control device wherein the initial operating force which is obtained is at a maximum at the beginning of the operator movement, as distinguished from devices in which the force exerted initially is a minimum. This is advantageous in that it provides a large initial or starting force for overcoming the inertia and friction of moving parts and a strong initial force which, for example, will overcome fluid pressures, for examplefln cracking or opening a valve wherein the controlled fluid, such as gas for a gas heater, usually tends to hold the valve closed.

Another object is to provide an improved form of electromagnetic operator wherein the magnetic air gap is never completely closed, and which air gap remains constant throughout the life of the device, as distinguished from electromagnetic devices wherein a magnetic part is attracted to and sealed against an electromagnet when energized or in which non-magnetic spacers are utilized in an attempt to maintain an air gap. The present device thereby eliminates any sticking or hang up of the attracted member, and substantially eliminates any differential in the pick up and drop out of the device as, for example, due to residual magnetism. The present invention thereby provides an electromagnetic operator of greater sensitivity and quicker response.

Another object is to provide an improved electromagnetic operating means for translation of electrical energy to rotary mechanical movement, and more particularly to rotary movement controlled both in direction and magnitude and wherein a magnetic stop is provided to prevent rotation of greater degree than that desired.

Another object is to provide a device of the aforementioned character wherein the movable parts are afforded magnetic stops and which is immune to the infiuence of gravity and may therefore be used in any position.

Another object is to provide a device of the aforementioned character which is quiet and eflicient in operation and which affords increased efficiency in the aforementioned transformation from electrical to mechanical energy, for example, in providing for a given size unit substantially increased output as compared to known devices of similar character.

Another object is to provide in a device of the aforementioned character an electromagnetic core affording an air gap and a magnetic rotor movable into said air gap when energized and out of said air gap when deenergized by biasing means matched to the electromagnetic energizing means to complement the inherent chartill Another object is to provide a device as aforementioned in which, when utilized as a valve operator, the operator biasing means also serve as support means for the movable valve parts, and further in which the valve may be rendered normally open or normally closed by mere reversal of the combination biasing-supporting means.

'ier object of the invention is to provide an electrotitally operated control device comprising a winding provided with a core having a first core portion through which flux established by energization of the winding is adapted to pass, the core having a second core portion provided with pole pieces defining an air gap, and there being flux diverting means operable to divert flux from the first core portion to the second core portion to cause movement of a magnetic rotor into said air gap for minimization of said gap.

Another object is to provide an electromagnetic device in which the core and windings for establishing and diverting the magnetic flux through the core constitutes a current limiting step-down transformer wherein the electric energy produced in a secondary winding may be relatively low and substantially constant, so that the secondary circuit and condition responsive means or other control apparatus therefor will not be deleteriously affected by the energizing current supplied to the primary, and so that the type of insulating conduits required for line voltage are unnecessary.

Another object of the invention is to provide a device Which is immune to short circuits on the secondary side of the transformer from the standpoint of damage due to overheating.

Another object of the invention is to provide a device of simple, compact, and relatively inexpensive construction, and in which particularly the rotor fabrication is simplified.

Another object is to provide a device of the character described which may utilize a non-laminated core thereby reducing cost and simplifying construction.

Another object is to provide a device of the character described which may be used on either alternating or direct current by mere changing of windings or coils.

Another object is to provide an improved rotor or rotary-type armature and an improved core which enables reduction in the mass and inertia of the rotor and at the same time provides armature portions of increased area.

Another object is to provide an improved relation between the electromagnetic operator and the valve or other controlled device; also a base plate having improved relation with respect to these parts and an improved actuating connection between the armature and the valve or other controlled device.

Further objects and advantages of the invention will appear from the following detailed description taken in connection with the accompanying drawings wherein the device of the present invention is illustrated as a valve operator, it being understood that the invention is limited only within the scope of the appended claims.

In the drawings:

Figure is an axial sectional view of one form of the device embodying the present invention including a secondary winding and showing schematically thermostatic means for controlling the secondary circuit;

Figures 1A and 1B are fragmentary views showing detail modifications;

Figure 2 is a sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on theline 33 of Figure 1;

Figure 4 is a plan view of the combined biasing spring and valve member supporting means;

Figure is a perspective view of the magnetic rotor employed in the device shown in Figure 1;

Figure 6 is an axial sectional view similar to Figure 1 illustrating a modified form of the device, in which the secondary winding has been omitted and the valve rendered normally open;

Figure 7 is an axial sectional view of still another modification of the device; and

Figure 8 is a partial sectional view taken on the line tl-f of Figure 7.

Referring first to Figures 15 of the drawings, the embodiment of the invention therein illustrated comprises avalve body 1 having afluid inlet 2 and a fluid outlet 3. A valve member 4 cooperates with avalve seat 5 at the outlet 3 to control the flow of fiuid through the valve, for example, the flow of gaseous fuel to a burner (not shown) or any other fluid. It will be noted that the controlled fluid tends to hold the valve member 4 closed. This may, of course, vary within the scope of the invention.

Thevalve body 1 has an opening 6 covered by anenclosure 7 for electromagnetic operating means hereinafter described, the bottom wall 7a ofenclosure 7 affording a plate-like cover for opening 6 and being secured in place, for example, by screws (not shown), threaded into thevalve body 1. Sealing means 6a is preferably interposed between the plate 7a andvalve body 1 to render the connection gastight. Theenclosure 7 is preferably a die casting of non-magnetic material such as aluminum.

The upper side of base plate 7a is provided with a pair of integrally formedupstanding arms 7b of configuration best shown in Figure 2, forming a partial enclosure for a rotor orrotary armature 8 hereinafter described.

Mounted on base plate 7a is a power unit comprising amagnetic core 9 of laminated, or of any other suitable form. The particular core selected for illustration is of generally rectangular configuration, comprising a pair ofparallel side legs 10 and 11 magnetically connected byparallel end legs 12 and 13.

The core is arranged in position with itslegs surrounding arms 7b of base plate 7a which arms serve to locate the core laterally while abutments 7} (Figure 2) integrally formed in the base plate 7a serve to locate the core lengthwise thereon. Theside legs 10 and 11 of the core a have spacedpole pieces 14 and 15 formed, for example, as integral parts of the core laminations, which pole pieces are of configuration best shown in Figure 2 and have arcuate inner edges defining with arms 71) of the base plate 711 a well in which therotor 8 is adapted to turn.

As best illustrated in Figure 1, the core is completed by a split core comprising a first cylindrical core piece 16 located at the bottom of the aforementioned well and attached to base plate 7a, and a second cylindrical core piece 17 suspended in said well from above, core piece 17 being supported therein by aplate 18 resting on suitable abutments formed at the upper ends ofarms 7!) and held in position as by large-headed screws 19 threaded intoarms 7b. Theplate 18 is preferably non-magnetic and suitably insulated with lacquer, anodizing or other means, to reduce eddy currents. Insulating washers are also preferably provided under the heads of thescrews 19 to reduce eddy currents.

Therotor 8 is of magnetic material, such as steel preferably fabricated by powder metallurgy techniques, and is of form best illustrated in Figure 5. In general, therotor 8 is of H-shape in vertical section as shown in Figure 1 and comprises a pair of arcuately formed arms 8:! and 8b joined by a connecting portion 80 midway between the ends of the arms. The connecting portion 80 is adapted to be positioned between the split core pieces 16 and 17 which provide bearing surfaces therefor as illustrated by the bearing 20 mounted on theshaft 21 which extends through and is non-rotatably connected to therotori8, and by the thrust bearing carried by core piece 17 comprising a ball 22 andcompression spring 23 trapped in asuitable recess 17a formed in core piece 17. The last-described bearing affords substantial tolerance in manufacture inasmuch as it need not be too closely aligned withshaft 21.

llC bearing 26a of theshaft 21a on the adjacent end of thesleeve 2% may be tapered as shown in Figure 1A.

As shown in Figures 1 and 2, the core pieces 16 and 17 are radially spaced from theupstanding arms 7b and pole faces 14 and a5 a sufiicient distance to afford clearance for "ins art and 8b ofrotor 8 through 360 of rotation. The split core diminishes the amount of material necessary in therotor 8 and hence decreases its inertia, while at the same time defining a relatively small air gap between the pole pieces ofcore 9 and the core pieces 16 and As will be apparent, this air gap need be no greater than the clearance needed for the arms of rotor at each of the pole faces 14 and 15. The aforementioned assembly is protected by an inverted cup-shapedcover 24 of non-magnetic material attached to core piece 17 as by ascrew 25. Thescrew 25 may be eliminated and thecover 24 held in place by the cover 41.

The power unit further comprises a primary winding 26 adapted to be connected to a suitable source of electrical energy, and a secondary coil or winding 27, the circuit of which may include condition responsive means such as the thermostat illustrated schematically at 28 in Figure 1. it will be understood that when the primary winding is energized, and the secondary circuit open, the magnetic fiux created in thecore 9 will tend to flow around the core through theend leg 12 upon which the secondary winding is mounted, in preference to jumping the air gap between pole faces 14 and 15, whereas when the secondary circuit is closed, induced currents in the secondary winding 27' will divert the magnetic flux across the aforementioned air gap to cause movement of the rotor as will hereinafter be described.

As shown in Figure l, theshaft 21 connected to rotor it extends downwardly through asleeve 29 carried by core piece 16 and extending through base plate 7a, the lower end ofshaft 21 being connected non-rotatably, but adjustably to one end of acrank member 30. A resilient or rubber-like O-shaped ring 31 is mounted in an annular groove near the lower end ofshaft 21 and Withinsleeve 29 to provide a gastight seal therebetween.

As best shown in Figure 3, the crank member is non-rotatably connected to theshaft 21 as by apin 32 for transmission of any movement ofrotor 8 to crankmember 30. At the opposite end of thecrank 30 is a downwardly extending in 33 off center with respect to the axis of rotation ofshaft 21. Thepin 33 is adapted to engage a yoke 34 (Fig. 1) connected at one end as by astem 35 andpin 36 to valve member 4.

The aforementioned yoke-valve member assembly is preferably suspended in thevalve body 1 as by a pair ofsprings 37 attached as byscrews 38 to a portion of thebase plate 7 extending downwardly through opening 6 of the valve body. Thesprings 37 serve both to support the valve member assembly in alignment with thevalve seat 5 and to bias both the rotor S and valve member 4 as will hereinafter become apparent. When thebase plate 7 carrying and enclosing the power unit aforementioned is removed and/or replaced, the valve member assembly is removable therewith as a unit.

Thesprings 37, as best shown in Figure 4, are shown of flat spiral configuration in plan and conically helical in edge elevation when uncompressed but numerous other configurations are contemplated. That is to say, when the turns are in a plane as shown in Figure 1 they are under compression and imparting a sealing force to valve member 4 against itsvalve seat 5. Movement of the valve member 4 to open position against the bias ofsprings 37 further compresses the latter. In this regard while, as aforementioned, the ends of the outermost turns of thesprings 37 are attached to base plate portion '70 as aforedescribed, the innermost turn in each case is attached to the yoke assembly as at 39 and 40.

The enclosure '7 is further provided with openings 7d and 7e for electrical conduit connections for the windings of the power unit, while the open top thereof is preferably provided with a cover 41 of non-magnetic material and of suitable form.

The valve member 4 selected for illustration is, in general, of the type more fully disclosed in the copending application of Carl Wolff, Serial No. 194,505, filed November 7, 1950, which has matured into latent No. 2,687,501, but may, of course, be of other suitable form.

The mode of operation of the aforedescribed device is as follows: Assuming theprimary coil 26 to be energized, as it will be under ordinary circumstances, since the device inherently has a very low stand-by power loss, a magnetic flux will be created in thecore 9 in a clockwise direction as viewed in Figure 2, the flux as aforementioned flowing through theleg 12 ofcore 9 so long as the circuit of secondary winding 27 remains open. The rotor t? is angularly disposed onshaft 21 so that in unenergized condition the leading edges of the rotor orarmature arms 8a and 3b are barely within the air gaps between the pole faces 14 and 15 and the core pieces 16 and 17; that is, a very small portion of the rotor 3 is presented to the pole faces 14 and 15 respectively as shown in full line in Figure 2. It is, of course, understood that the angular disposition ofshaft 21 and hencerotor 8 when unenergized as determined by the bias afforded by thesprings 37, also supporting and biasing the valve member 4. In the embodiment illustrated in Figure l, the seating of valve member 4 against thevalve seat 5 under the bias ofsprings 37 limits the rotation ofrotor 8 and provides a stop therefor in its unenergized state.

When the circuit of secondary winding 27 is closed, as for example, by closure of the contacts of thethermostat 28, the magnetic flux ofcore 9 willl no longer flow throughleg 12 thereof, but will be diverted to thepole pieces 14 and 15. Since the flux will cross the air gap therein at the point of minimum air gap, and since the minimum air gap occurs at the points where the leading edges of therotor 8 are presented to the pole pieces, the magnetic flux will be concentrated at those points imparting a counterclockwise torque to therotor 8. The inherent tendency of the device is to tend toward a condition of minimum air gap. Hence therotor 8 will be rotated into the air gap until thearms 8a and 8b thereof are in registry with the pole faces 14 and 15 respectively as shown in dotted lines in Figure 2. Further rotation of the rotor S will not occur since such movement would tend to increase the air gap, and movement of the leading edges of the arms 8:: and 8b beyond the pole faces would set up magnetic forces creating a torque in the opposite direction. Therotor 8 is thereby afforded a magnetic stop limiting its rotation in counterclockwise direction as viewed in Figure 2 to a position wherein the arms ofrotor 8 are in registry with the pole faces ofcore 9 as aforedescribed.

The foregoing phenomenon may be further elucidated by reference to the mathematical relationships involved which may be expressed as follows:

B A F 72 lbs.

where F is the force of attraction brought to bear upon therotor 8 expressed in lbs., B is the magnetic flux density, and A is the area ofrotor 8 presented to thepole pieces 14 and 15. From this relationship it will also be seen that the device described inherently imparts a greater force at the beginning of the stroke than at the end thereof. A (the area of the rotor presented to the pole pieces) increases as the rotor approaches registry with the pole pieces, however, since B (the flux density per unit area) decreases as A increases, and in the formula B is squared, the net result is that F varies inversely with A. For example, if the rotor area presented to the pole pieces is .0508 square inch when the rotor is un energized and the total area of the rotor arms which may be presented to the pole pieces when in registry therewith is .71 square inch, the force at the beginning of the stroke will be 13.95 times the force exerted at the end of the stroke. This relationship has obvious advantages in that the rotor torque varies in the same manner as the forces required to operate a mechanism requiring greater force to initiate movement thereof than to maintain such movement, as for example, a valve member such as member 4 which must be moved against fluid pressure initially.

it is, of course, understood that rotation of therotor 8 and consequent movement of valve member 4 through the linkage ofshaft 21, crankmember 30 andyoke 34 is against the bias ofsprings 37, which return both the valve members 4 androtor 8 to their initial position upon deenergization of the rotor as, for example, by reopening of thethermostat 28.

in this connection, it may be observed that the spring rate of the biasing means may be matched to the torque characteristics of the rotor to enhance its desired characteristic.

It should further be noted that such return will be prompt and without danger of sticking since therotor 8 never seals against thepole pieces 14 and 35; that is, the air gap therebetween, although minimized by registration of the rotor arms with the pole pieces, is never completely eliminated and remains constant throughout the life of the device. The device is therefore not subiect to residual magnetism of thecore 9, the differential in the flux value required to pick up the rotor and that at which it will drop out is greatly minimized, thereby rendering the control extremely sensitive and fast acting.

Another desirable feature of the aforedescribed device is that it is inherently more etlicient than known electromagnetic operators as, for example, the power requirement is about one third that of a conventional solenoid operator capable of actuating a valve of the same size.

in actual practice therotary armature 8 may be raised so that the top of the rotary armature will be above themagnetic core 9 as shown in Figure 1B. This tends to hold the rotor down by magnetic force when the unit is operated.

In Figure 6 there is illustrated a modification of the device shown in Figure 1, wherein similar parts have been given primed reference numerals corresponding to the reference numerals used in Figures 1-5. The device in Figure 6 differs from that previously described first in that i thecore leg 12 and secondary coil 2'7 and its circuit have been omitted, control of the device being obtained by simple commutation of the primary circuit.

Secondly, the valve member 4' as shown in Figure 6 is normally open. This is to illustrate the ready adaptability of the device to either a normally open or normally closed form. it will be observed that to obtain such modification, it is necessary merely to turn thesprings 37 about so that in uncompressed condition they bow to the right as seen in Figure 6, and to alter the angular position ofcrank member 30 onshaft 21 by The mode of operation of the device of Figure 6 is substantially similar to that of Figure 1, except that now counterclockwise rotation of therotor 8 into registry with thepole pieces 14 and 215 with energization of the primary winding imparts a movement to closed position of valve member 4 against the bias ofsprings 37.

Thus it is apparent that the devices aforedescribed may be readily adapted to control with or without utilization of the secondary winding flux diverting feature and to either normally open or normally closed forms by sinmple adjustment and/or addition or omission of certain parts. It will also be apparent that Where the secondary winding is not utilized as, for example, where the transformer feature atfording a low power secondary circuit is not needed or desired, the device may be operated on either A. C. or D. C. by mere selection and/or substitution of primary windings designed for A. C. or D. C. respectively. Where it is desired to utilize the secondary Winding and its control circuit with D. C. power in the primary winding, it is necessary merely t arrange the coils to oppose each other.

In Figures 7 and 8 is illustrated still another modification of the embodiment of the invention aforedescribed particularly adapted to control of smaller valves, and relatively less expensive to fabricate.

The device comprises a valve body ml similar to thevalve body 1 of the preceding devices, but of smaller dimensions. Thevalve body 131 has inlet andoutlet openings 1%.? and respectively, and avalve seat 1% against which a valve member N4 is adapted to seat. The valve body has an opening 7.96 adapted to be closed by a base plate 107 of non-magnetic material, a sealing gasket 196a being interposed between the base plate 107 and mating surface of valve body to insure a gastight connection therebetween.

The base plate 197 carries a magnetic core N9 of configuration best shown in Figure 7 and attachedto the base plate as byscrews 11 Thecore 1 Il9 may be of cast iron or the like and of relatively less cost than laminated structures ordinarily employed. Atransverse leg 30% carries an energizing winding or coil 111 and the whole assembly is positioned on base plate it to straddle a bridge member 132 also carried by the base plate and disposed thereon at right angles to the core 169 as best shown in Figure 8. Acover member 14% encloses the aforedescribed structures.

The bridge member 112 affords for a magnetic rotor 103 an upper thrust bearing comprising asteel ball 122 and compression spring 123 similar to that employed in the preceding devices and trapped in a recess 112a of the bridge member.

The rotor 108 is substantially similar to one half of therotor 8 previously described, the defending portions of the rotor arms being omitted. Thus rotor 168 comprises upstanding arms M811 and ltlSb connected by an integrally formed transverse portion who. Ashaft 121 extends through and is non-rotatably connected to transverse portion 108: of therotor 1% for rotation therewith. Theshaft 121 has a bearing 12% engaging a sleeve 129 extending through the base plate 167, theshaft 121 extending through the sleeve 129 into the valve body till and having a gastight seal with the sleeve 129 afforded by theO ring 131.

The lower end of theshaft 121 carries a crankmemher 130 and pin 133 similar to that previously described and having a similar connection with a yoke member 134 for transmitting movement of the rotor 108 to the valve member 104- as in the previously described devices. Similarly the valve member assembly is both supported in thevalve body 101 and biased to a given position bysprings 137 attached to the lower side of base plate 167. Here also reversal of thesprings 137 affords a normally closed or normally open valve.

The pole faces of the core 109 in this embodiment of the invention are on the inner sides of the core 109 as at 114 and 1 15, respectively. In Figure 8 therotor arm 1%]; is shown in registry with the pole face 114 indicating energization of the winding 111 from a suitable source of energy (not shown).

The mode of operation of the device of Figures 7 and 8 is similar to that of the preceding devices and all of the desired features inherent in the latter are also present in the present modification. in addition this modification aifords greatly reduced cost of construction for small valve operators in affording, for example, less costly core construction, smaller and less costly rotor construction, elimination of the split core, and the like.

We claim:

1. An electromagnetic operator comprising a permeable core having pole faces atfording a pair of generally diametrically oppositely disposed air gaps, a magnetic armature for each of said air gaps, a winding positioned outside the space between said pole pieces which when energized is adapted to produce a magnetic flux in said core, said armatures being rotatable about an axis at substantially right angles to the spacing of said pole pieces and positioned outside said winding, connections between said armatures insuring movement thereof together into their respective air gaps upon creation of a magnetic flux therein, the force afforded by said armatures being additive thereby alfording increased force for the operator for a given value of flux density.

2. An electromagnetic operator comprising a permeable core having pole pieces affording a pair of generally diametrically oppositely disposed air gaps, a magnetic rotor having a pair of arms one for each of said air gaps whose areas approximate the areas of said pole pieces, the axis of rotation of said rotor being located etween and at substantially right angles to the spacing of said pole pieces, means biasing said rotor to a position wherein only small portions of said rotor are presented to said pole pieces, a winding for said core positioned outside the space between said pole pieces which when energized produces a magnetic flux therein, which flux is adapted to flow through said air gaps via said rotor and inherently tends to minimize said air gaps by imparting sufficient rotary motion to said rotor to bring the arms of the latter into registry with said pole es, the force exerted by said flux upon said rotor varying inversely with the rotor arm area presented to said pole pieces whereby said rotor is atorded maximum torque at the beginning of each stroke.

3. An electromagnetic operator comprising pernieable core having pole pieces and a cylindrical split core portion disposed between said pole pieces and spaced radially therefrom to form an air gap, a magnetic rotor concentric with said split core having arms adapted to move in said air gap and a connecting part movable in the split in said core portion, means biasing said rotor to a position wherein only small portions of said rotor arms are presented to said pole pieces, means for producing a magnetic flux in said permeable core, which flux is adapted to flow through said air gap via said rotor at the point of minimum air gap and which inherently tends to minimize the total air gap by increasing the rotor arm area presented to the pole pieces thereby imparting suflicient rotary motion to said rotor to brin the arms thereof into registry with said pole pieces, said flux providing a magnetic stop to limit further rotation of said rotor.

4. An electromagnetic device comprising actuating means including a permeable core having an air gap, a rotor having its axis of rotation within said air gap,

eans for producing a magnetic flux in said core and through said air gap, said rotor having a portion adapted to be drawn into said air gap by said flux in satisfaction of its inherent tendency to minimize said air gap, thereby imparting rotary motion to said rotor, 'a member to be actuated by said actuating means, means for transmitting the rotary'movement of said rotor to said member, and spring means affording support for said member and biasing said member to a given position and at the same time controlling the angular displacement of said rotor to bias the latter to a position wherein the portions thereof adapted to be drawn into said air gap are barely within said air gap.

5. An electromagnetic control device comprising a permeable core having an air gap, a winding which when energized is adapted to produce a magnetic flux in said core, a magnetic armature mounted for turning movement about. an axis and initially positioned with respect to said core so as to be drawn into said air gap by said magnetic flux with resultant turning motion of said armature, 'a stoplimiting turning movement of said armature in one direction and defining said initial position, biasing means controlling the angular displacement of said armature and biasing the latter toward said initial position wherein a relatively small portion thereof lies within said air gap, said flux affording a magnetic stop limiting turning movement of said armature in the other direction to a position of registry with said air gap, and a controlled device having two different positions, said biasing means supporting said controlled device and biasing the latter toward one of said positions, said controlled device being actuated to the other position against said bias by drawing of said armature into said air gap.

6. An electromagnetic control device according to claim,5 wherein the biasing means comprises a pair of springs of spiral configuration fixedly supported at their outer ends and supporting the controlled device at their inner ends.

7. An electromagnetic control device according toclaim 5 wherein the biasing means comprises a pair of springs of spiral configuration fixedly supported at their outer ends and supporting the controlled device at their inner ends, said springs having their turns in planes when under compression and biasing the controlled device to one of its positions, the inner ends of the springs being displaced axially from such planes by the actuation of the controlled device to its other position.

8. In a device of the class described, in combination, a non-magnetic base plate, a sleeve extending through said base plate, a generally cylindrical first magnetic core portion carried by said sleeve on one side of said base plate, a second magnetic core portion in surrounding relation to said first core portion and having pole pieces provided with arcuate faces in spaced relation to and on diametrically opposite sides of said first core portion to form arcuate air gaps therebetween and radially outwardly of said first core portion, an armature mounted for turning movement about the axis of said first core portion, said armature having a pair of longitudinally extending arcuate armature arms one movable into each of said air gaps between said cylindrical first core portion and said pole pieces to permit flux flow diametrically from one pole piece successively through one of said armature arms, said cylindrical core portion and the other armature arm to the other pole piece, and a connecting web extending between said arcuate and longitudinally extending armature arms and connecting them for turning movement in unison, said connecting web extending across one end of the first core portion.

9. A device according toclaim 8 wherein there is a shaft extending through said sleeve and said first core portion and non-rotatably connected to the connecting web of the armature.

10. A device according toclaim 8 wherein there is a shaft extending through said sleeve and said first core portion and non-rotatably connected to the connecting web of the armature, a bearing for said shaft on said sleeve at one side of the connecting web, and a thrust bearing cooperating with the end of the shaft at the opposite side of said connecting web.

11. A device according toclaim 8 wherein there is a generally cylindrical third magnetic core portion coaxial with and spaced endwise from said first core portion with the arcuate faces of the pole pieces also in spaced relation to and on diametrically opposite sides of said third core portion to form arcuate air gaps therebetween and radially outwardly of said third core portion, the longitudinally extending arcuate armature arms being also movable into said latter air gaps between said third core portion and said pole pieces, and the connecting web extending between said first and third core portions.

12. A device according toclaim 8 wherein there is a generally cylindrical third magnetic core portion coaxial with and spaced endwise from said first core portion with the arcuate faces of the pole pieces also in spaced relation to and on diametrically opposite sides of said third core portion to form arcuate air gaps therebetween and radially outwardly of said third core portion, the longitudinally extending arcuate armature arms being also movable into said latter air gaps between said third core portion and said pole pieces and the connecting web being of magnetically permeable material and integral with said armature arms, said web extending between said first and third core portions.

13. A device according toclaim 8 wherein there is a controlled member connected to the shaft on the other side of the base plate and operable from one position to another position by turning movement imparted to said armature by the production of magnetic flux across the air gaps at the places of minimum air gaps.

14. A valve comprising a valve body provided with a valve seat, a valve member cooperable with said seat, an actuating member by Which said valve is carried, and a pair of spaced generally parallel spiral supporting and biasing springs operatively connected to said actuating member for supporting the latter and said valve member for rectilinear reciprocation toward and away from said seat in a direction generally normal to the planes of said springs, said springs also biasing said members in the direction toward said seat and thereby biasing said valve member toward sealing engagement with said seat.

15. A valve comprising a valve body provided with a valve seat, a valve member cooperable with said seat, an actuating member by which said valve is carried, a pair of spaced generally parallel spiral supporting and biasing springs operatively connected to said actuating member for supporting the latter and said valve member for rectilinear reciprocation toward and away from said seat in a direction generally normal to the planes of said springs, said springs biasing said members in the direction toward said seat and thereby biasing said valve member toward sealing engagement with said seat, an operator comprising a crank arm disposed between said springs and rotatable on an axis generally parallel with the planes of said springs, and an operative connection between said crank arm and said actuating member affording movement of said valve member away from said seat against said bias on rotation of said crank arm in one direction.

16. An electromagnetic operator comprising a magnetic frame having an air gap, a primary winding afford ing when energized magnetic flux in said frame, a secondary winding having a circuit supplied therefrom, said magnetic flux inducing a current in said secondary winding when said circuit is closed to divert said magnetic flux across said air gap, a magnetic rotor mounted for rotation into said air gap when magnetic flux is diverted therethrough, a crank arm engaged for rotation with said rotor, an actuating member adapted for connection to a member to be controlled, a pair of spaced spiral supporting and biasing springs supporting said actuating member in a manner to permit reciprocating movement thereof and biasing said member toward a first position, and an operative connection between said crank arm and said actuating member afi'ording movement of said actuating member to a second position against said bias on movement of said rotor into said air gap.

17. An electromagnetic operator comprising a magnetic frame having an air gap, 2. primary winding affording when energized magnetic flux in said frame, a secondary winding having a circuit supplied therefrom, said magnetic flux inducing a current in said secondary winding when said circuit is closed to divert said magnetic flux across said air gap, a magnetic rotor mounted for rotation into said air gap when magnetic flux is diverted therethrough, a crank arm en aged for rotation with said rotor, an actuating member adapted for connection to a member to be controlled, a pair of spaced spiral supporting and biasing springs supporting said actuating member in a manner to permit reciprocating movement thereof and biasing said member toward a first position, and an operative connection comprising interdigitating portions on said crank arm and actuating memaifording movement of said actuating member to a second position against said bias on movement of said air gap and affording return movement of said rotor to "ts initial position and said actuating member to its first position under said bias when flux is longer diverted across said air gap.

18. An electromagnetic operator comprising a magneticaily permeable frame having a flux path including spaced pole piece portions formed with spaced arcuate concentric diametrically opposed pole faces defining an air gap, an energizin winding affording when energized magnetic fiux flow in said flux path, a magnetically permeable actuating member rotatable on an axis coaxial with said pole faces and interposed therebetween in substantially planar alignment therewith, said actuating member having concentric diametrically opposite arcuate peripheral surface portions, and deformable biasing means biasing said actuating member toward a first position in which a portion of each of said peripheral surfaces is presented in face-to-face relation with an adjacent arcuate pole face, said flux flowing substantially diametrically from one pole face through said air gap and diametrically through said actuating member from one of said peripheral surface portions to the other and thence to the other pole face to magne .lly rotate said actuating member in a direction increasing the area of said peripheral surfaces presented to said pole faces and with maximum force at the beginning of its rotation against the bias of said biasing means,

deforming said biasing means to cause the latter to exert increasing biasing force with increasing deformation, said actuating member quietly coming to rest at a second position defined substantially solely by equalization of the decreasing magnetic actuating force on said member and the increasing biasing force of said biasing means.

19. An electromagnetic operator comprising a magnetically permeable frame having a first closed magnetic flux path and a second fiux path including spaced pole piece portions formed with spaced arcuate concentric diametrically opposed pole faces defining an air gap, an energizing winding afiording when energized magnetic flux flow in said first flux path, means for shunting said magnetic flux from said first path to said second path and diametrically across said air gap, means controlling said flux shunting means and thereby the shunting of flux across said air gap, a magnetically permeable actuating member rotatable on an axis coaxial with said pole faces and interposed therebetween in substantially planar alignment therewith, said actuating member having concentric diametrically opposite arcuate peripheral surface portions, and deformable biasing means biasing said actuating member toward a first position in which a portion of each of said peripheral surfaces is presented in face-to-face relation with an adjacent arcuate pole face, said shunted flux flowing substantially diametrically from one pole face through said air gap and diametrically through said actuating member from one of said peripheral surface portions to the other and thence to the other pole face to magnetically rotate said actuating member in a direction increasing the area of said peripheral surfaces presented to said pole faces and with maximum force at the beginning of its rotation against the bias of said biasing means, deforming said biasing means to cause the latter to exert increasing biasing force with increasingdeformation, said actuating member quietly coming to rest at a second position defined substantially solely by equalization of the decreasing magnetic actuating force on said member and the increasing biasing force of said biasing means.

References Cited in the file of this patent UNITED STATES PATENTS 700,839 Sessions May 27, 1902 719,768 Engberg Feb. 3, 1903 969,493 Pierson Sept. 6, 1910 1,053,340 Ziegler Feb. 18, 1913 1,201,826 Iversen Oct. 17, 1916 1,383,087 Dunn June 28, 1921 1,764,658 Stoecklin June 17, 1930 1,979,127 Warrick Oct. 30, 1934 2,226,345 Lozivit Dec. 24, 1940 2,353,467 Hennessy July 11, 1944 2,538,700 Mersh-on Jan. 16, 1951 2,541,937 Powers Feb. 13, 1951 2,563,495 Schleicher Aug. 7, 1951 2,687,501 Wolff Aug. 24, 1954 FOREIGN PATENTS 613,856 Great Britain Dec. 3, 1948

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