US2435425A

US2435425A - Magnetic control device

Info

Publication number: US2435425A
Application number: US482880A
Authority: US
Inventors: Lewis L Cunningham
Original assignee: General Controls Co
Current assignee: General Controls Co
Priority date: 1943-04-13
Filing date: 1943-04-13
Publication date: 1948-02-03
Anticipated expiration: 1965-02-03

Description

Feb. 3, 1948. 1.. 1.. CUNNINGHAM MAGNETIC CONTROL DEVICE Filed April 13, 1943 2 Sheets-Sheet 1 5 b we,

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Feb. 3, 194a. L. 1.. CUNNINGHAM 2,435,425

MAGNETIC CONTROL DEVICE y Filed April 15, 1945 2 sneetsfsnet 2 17 .5- IPA e9 4 I Zh'wcntor:

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Patented Feb. 3, 1948 UNITED STATES PATENT OFFICE MAGNETIC CONTROL DEVICE Lewis I. Cunningham, Los Angeles, Calif., as-' signor to General Controls 00., Glendale, Caiit, a corporation of California Application April 13, 1943, Serial No. 482,880 6 Claims. (01. 175-330) My present invention relates to magnetic control devices of the type which includes an armature movable to operate control means such as electrical contacts, pilot valves, or the like. More particularly, the invention relates to such devices wherein a permanentmagnet is provided for normally. holding the armature in attracted position, and having means movable into the field of the magnet for so shunting the flux thereof that the armature is released.

An object of this invention is to provide a control device, of the character described, wherein the magnet is of U-shape and the shunting means is movable to a position between the side arms of the magnet, or adjacent the polar ends thereof.

Another object is to provide a device, of the character described in the preceding object, wherein the armature is disposed in a plane substantially parallel to that of the arms of the magnet so that a compact structure is formed.

Another object is to provide the U-shaped magnet with means which extend irom the polar ends of the magnet, in a direction at right-angles to the plane of the arms thereof, to form pole faces in a plane parallel to that of the arms.

Another object is to provide the control device with an additional U-shaped magnet which is arranged with its polar ends adjacent, and opposed to, the polar ends of the other magnet; thereby minimizing the leakage flux of the magnets, and permitting the shunting means to be symmetrically arranged between the polar ends of the magnets.

'A still further object is to provide, in the application of the above-described control device to a fluid control valve, means connecting the shunting means to the closure member of the valve, and means interposed between the shunting means and the magnet for shielding the control device from the fluid controlled by the valve.

Other objects and advantages of the invention will be found in the description, the drawing, and

the claims; and, for full understanding of the invention, reference may be had to the following detailed description and accompanying drawing, wherein:

Figure l is a longitudinal sectional view of a fluid control valve which includes, at its upper end, a magnetic control device embodying my invention;

Figure 2 is a transverse section taken along the line 2-2 of Fig. 1;

Figure 3 is a fragmentary longitudinal section taken along the line 3-3 of Fig. 2;

Figure 4 is a view, in perspective, of the magnetic control device shown in Figs. 1-3; and

Figures 5, 6 and 7 are diagrammatic views of typical control systems which include the mag- .netic device.

Referring first to Figs. 1-4 of the drawing, the

2 numeral ll indicates a valve casing having a ported partition l2 providing a valve seat I] with which a closure member I4 cooperates. Mounted on the apertured top wall of the casing is an electromagnetic operator comprising a hollow cylindrical core ii, an annular coil winding I8, and a reciprocable plunger I! which is connected by a stem 18 to the closure member I. On the top of the core I! is a disk-shaped base IQ, of insulating material, which supports the magnetic control device of the invention. The base is mounted on the core by means of a pair of screws 20, extending from the core, which pass freely through holes in the base and are provided at their ends above the base with nuts 2|. Around the portion of each of the screws 20 below the base is is a compression spring 22 which urges the base into engagement with the nuts 2|. By turning these nuts, the base can be adjustably moved along the axis of the electromagnet. Enclosing the space above the electromagnet is a cap 23, through the top wall of which there extend th leads 24 of the electromagnet coil winding l6 which pass through openings in the core I5 andbase II.

On the base I! is a pair of U-shaped permanent magnets 25-26 which are arranged in a, single horizontal plane with the free ends of their respective side arms in adjacent relation. The magnets are secured to the base by a pair of rectangular posts 21-28 (Fig. 4) which are interposed between the adjacent ends of the side arms of the magnets in abutting relation thereto and are provided with enlarged head portions 29-30 for engagement with the top surfaces of the magnets; the posts being secured to the base by screws M (Fig. 3). The magnets 25-26 are arranged in opposing relation, i. e., the adjacent ends of the side arms of the magnets have the same polarity, as is indicated by the letters N and S in Fig. 4. The posts 21-28 are of magnetic material, such as soft iron, and their top surfaces thus form a pair of pole faces, marked N and S, which are efl'ectively the common poles of the two magnets. Cooperable with the magnets, and positioned im-. mediately above and substantially parallel to the pole faces of posts 21-28, is an armature 22 (Fig. 3) which is attached at its bent-up left-hand end to an apertured flexible metal strip or hinge 33 which is supported by an angle bracket 34 secured to the base is by screws 25. The armature 32, carries a switch arm 28 which cooperates with contact screws 31-38 threaded respectively in brackets 38-40 secured to the base IS. The switch constituted by arm 38 and contacts 31-" is adapted to be connected in circuit with apparatus, to be controlled in accordance with the switch arm position, by connecting the leads of the apparatus to the

brackets

24, 38 and lo-no such connections being shown in Figs. 1-4. The

armature is normally held by the magnets in attracted position with respect to the pole faces of posts 21-28 (so that the switch arm is in engagement with the lower contact screw 31) and is biased in a direction away from the pole faces by the force of a tension spring 4| which is tightly threaded at its lower end on screw 35 (Fig. 3) and is freely threaded at its other end on a screw 42 which is a clearance fit in an opening through an extension 43 of the armature. By turning screw 42, the tension of spring 4| can be adjusted.

Connected to the upper end of the electromag-' net plunger I1 is a rod 44 having at its top an enlarged portion or head 45, of soft iron, which is a sliding fit within theereduced tubular upper portion 46 of a non-magnetic cup or liner 41 having at its mouth a flange 48 which is interposed at its margin between the valve casing I I and the core ii. The liner 41 serves to shield the electromagnet and the magnetic switching device from the fluid controlled by the valve. as well as to magnetically separate the upper portion of the plunger I! from the core l when the plunger is raised by energization of coil IS. The reduced upper portion 48 of the liner extends through central openings in the core I! and base l9 and is of such length that its closed top end is approximately flush with the pole faces of the posts 212l; the outer side surface of the portion 48 being in engagement with the inner corners 49 (Fig. 4) of the side arms of the magnets which are ground to conform thereto.

When plunger I! is raised by energization of its electromagnet, the soft-iron head 45 of rod 44 is interposed between the polar ends of the magnets 252i so that the flux thereof is shunted by the head, the resultant reduction of magnetic attraction of the armature permitting the force of its bias spring 4| to move it in a direction away from the magnets so that the switch arm 36 engages the upper contact screw 38. When, upon deenergization of the electromagnet, the head 45 is retracted, the armature returns to its attracted position as shown. In the structure of Figs. 1-4, the controlling function of the magnetic switching device does not appear, since the structure is intended merely to illustrate the arrangement of the device with respect to typical means for operating the shunting head 45. However, it is apparent that the switching device could be employed to control an electrical circuit including means, such as signal lights, for remotely indicating the condition of the closure member of the valve. In some applications of the switching device, it is important that the armature be released or attracted when the shunt operating means reaches a particular point in its travel; for that reason, the base I 9 is arranged so that it can be raised or lowered (as has been described) to determine that point, it being understood that under normal bias of the armature the same is released when the shunting head 45 is inserted only partially between the magnets. Referring now to the diagram of Fig. 5, the magnetic switching device, described in connection with Figs. 1-4, is shown in simplified form. It comprises a switch blade 60 which is biased by its own resilience in an upward direction. Attached to the underside of the switch blade is an armature 6| which cooperates with a single U-shaped permanent magnet 82, the polar ends of which are marked N and S. Carried by a solenoid plunger 63, having an energizing coil winding 64, is a soft-iron rod 85 which is arranged to project between the side arms of the magnet 62, when plunger 63 is in its raised position as shown, to shunt the flux of the magnet so that the armature assumes its unattracted position wherein the switch bladeis in engagement with a contact element 66. Extending from the bottom of plunger 53 is a stem 41 which, by w of example, is shown provided with a closure member 68 cooperable with a valve seat 69. The lower portion of stem ll is reduced in diameter to provide a shoulder II with which an electromagnetic latching plunger ll cooperates. This plunger is biased toward the valve stem by a compression spring I! and is retractable therefrom upon energization of its coil winding 11. The coil windings 44 and II are connected at one of their ends to

contacts

14 and 15, respectively, which are engageable by a manually-operable switching member Ii. The

other end of the main plunger winding 44 is connected to a contact element 11 which is engageable by the switch blade 60 when the armature BI is in its attracted position with respect to magnet 42; the other end of the latching plunger winding 13 being connected to the upper contact element 8|. The switching member 16 is connected, in series with a source of electrical energy II, to ground; switch blade I also being grounded. Thus. when the switching member 18 is moved into engagement with contact ll, current then flows through the latching plunger winding 13 (contact element 44 being engaged by switch blade 80), thereby eflecting retraction of the latching plunger so that the main plunger 8! falls by gravity. In the downward movement of the main plunger, the softiron rod is removed from the field of magnet 62 so that armature Cl is downwardly attracted, thereby effecting disengagement of switch blade 60 from contact 44 so that the energizing circuit of the latching plunger ll is broken and that plunger moves into engagement with the unreduced upper portion of stem 61. If thqswitching member is now moved back into engagement with contact I4, current flows through the winding 64 of the main plunger (switch blade 4. now being in engagement with contact element 1'!) and that plunger moves upwardly; the plunger H being forced by its bias into latching position below shoulder 10 when the main plunger is near the end of its stroke. Slight continued upward movement of the main plunger eflects magnetic release of the armature, by shunting of the magnet flux by rod 65, so that the resultant separation of the switch blade from contact 11 breaks the main plunger circuit: the parts assuming the positions shown in Fig. 5.

In Fig. 6. the main parts are identical with those of Fig. 5 and have therefore been assigned the same reference numerals and need not further be described. The chief difference lies in the provision of a momentary-contact manuallyoperable switching member 19 for controlling the energizing circuits of the main and latching plunger coil windings i4 and 13, so that it is not necessary to automatically break these circuits (as in Fig. 5) upon completion of the plunger stroke-the right-hand ends of the

windings

64 and 13 leading directly to ground, as indicated. The magnetically operated switch The manual switching member I! is biased by its own resilience to a neutral position out of engagement with contacts 14 and I5. The parts are shown in the figure in the positions assumed after the member 18 had momentarily been brought into engagement with contact 14 so that the main plunger 63 was raised to its latched position, thereby effecting ma netic release of armature 6| due to the shunting of magnet 62 by rod 65the condition of the main plunger being indicated by the resultant energization of the circuit of signal light. If the lower contact I is now engaged by member 19, the latching plunger II is retracted and the main plunger falls-the resultant downward attraction of armature 6| effecting deenergization of signal light 80 and energization'of the other light 8!.

In the arrangement of Fig. 7, the magnetic switching device is employed to control the lifting-coil circuit of a solenoid plunger 83 having a lifting coil 84 and a holding coil 85. These coils are connected together at one of their ends and to a contact 86 which is engageable by a manually-operable switching member 81 which is adapted to connect the ,source 18 to the coils in common. The other end of the lifting coil 84 is connectable to ground, through the contact 11 of the magnetic switching device, to complete its energizing circuit; the other end of holding coil 85 being directly grounded. In the figure,

the plunger 83 is shown held in its raised position switching device assuming its attracted position with blade 60 in engagement with contact 11. If the member 81 is then reclosed, both lifting and holding coils are simultaneously energized and the plunger is raised, the circuit of the lifting coil 84 being automatically opened when the plunger approaches the end of its stroke, due to release of blade 60 from contact 11; the continued energization of coil 85 then sufficing to hold the plunger in its raised position.

While I have'herein shown and described a specific embodiment of my invention, I wish it to be understood that modifications may be made without departing from the spirit of the invention, and that I intend therefore to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a magnetic control device: a U-shaped permanent magnet, flux-conducting means extending from each of the polar ends of the arms of said magnet in a. direction at right-angles to the plane of the arms of the magnet to form a pair of pole faces in a plane parallel to said arms, a generally flat armature cooperable with the magnet and disposed in a plane substantially parallel to that of said pole faces, said armature normally being held by the magnet in attracted position with respect to said pole faces and biased in a direction away from them, and means movable into a position between the side arms of the magnet for so shunting the flux thereof that the armature then moves under the force of said bias.

2. In a magnetic control device: a U-shaped permanent magnet, a generally flat armature that of of the magnet and adjacent one side of said arms, said armature normally being held by the magnet in attracted position with respect thereto and biased in adirection away from it, and means insertable between the arms of the magnet from the side thereof away from the armature and movable in a direction at right-angles to the lane of said arms, said means when in inserted position being effective to so shunt the flux of the magnet that the armature then moves under the force of said bias.

3. In a magnetic control device: a U-shaped permanent magnet, flux-conducting means extending from each of the polar ends of the arms of said magnet in a direction at right-angles to the plane of the arms of the magnet to form a pair of pole faces in a plane parallel to that of said arms, a generally flat armature cooperable with the magnet and disposed in a plane substantially parallel to that of said pole faces, said armature normally being held by the magnet in attracted position with respect to said pole faces and biased in a direction away from them, and means insertable between the arms of the magnet from the side thereof away from the armature and movable in a direction at right-angles to the plane of said arms, said means when in inserted position being effective to so shunt the flux of the magnet that the armature then moves under the force of said bias.

4. In a magnetic control device: a pair of U- shaped permanent magnets arranged in a single plane with the poles thereof in adjacent and magnetically-opposed relation, a generally flat armature cooperable with said magnets and disposed in a plane substantially parallel to that of the arms of the magnets and adjacent one side of said arms, said armature normally being held by the magnets in attracted position with respect thereto and biased in a direction away from them, and means insertable between the arms of the magnets from the side thereof away from the armature and movable in a direction at rightangles tothe plane of said arms, said means when in inserted position beingeffective to so shunt the flux of the magnets that the armature then moves under the force of said bias.

5. In a magnetic control device: a pair 01 U- shaped permanent magnets arranged in a single plane with the poles thereof in adjacent and magnetically-opposed relation, flux-conducting means interposed betweeneach of the adjacent pairs of poles of said magnets and extending at right-angles to the plane of the arms of the magnets to form a pair of pole faces in a plane parallel to that of said arms, a generally flat armature cooperable with the magnets and disposed in a plane substantially parallel to that of said pole faces, said armature normally being held by the magnets in attracted position with respect to said pole faces and biased in a direction away from them, and means insertable between the arms of the magnets from the side thereof away from the armature and movable in a direction at right-angles to the plane of said arms, said means when in inserted position being cooperable with said magnet and disposed in a effective to so shunt the flux of the magnets that the armature then moves under the force of said bias.

6. In a magnetic control device: a pair of U- shaped permanent magnets arranged in a single plane with the poles thereof in adjacent and magnetically-opposed relation; flux-conducting means interposed between each of the adjacent pairs of poles of said magnets and extending at right-angles to the plane or the arms 01 the magnets to form a pair of pole faces in a plane parallel to that or said arms, a flat elongated armature cooperable with the magnets and disposed in a plane substantially parallel to that of said pole faces, said armature being pivoted at one end and lying transversely of the common axis of the magnets. said armature normally being held by the magnets in attracted position with respect to said po1e faces and biased 10 in a direction away from them, and means insertable between the arms of the magnets from the side thereof away from the armature and movable in a direction at right-angles to the plane of said arms, said means when in inserted position being efiective to so shunt the flux of the magnets that the armature then moves under the force of said bias.

LEWIS L. CUNNINGHAM. go

8 amneucns crrnn The following references are of record in the me of this patent:

UNITED STATES PATENTS Number Number Germany June 17, 1922