US2012064A - Electromagnetic switch - Google Patents

Description

Aug. 20, 1935. R. R. GoNsETT ELECTROMAGNETIC SWITCH Filed Jan. 25, 1932 in M ATTORNEY.

Patented Aug. 20, 1935 UNITED STATES PATENT OFFICE ELECTBOMAGNETIC SWITCH Application January 25, 1932, Serial No. 588,796

10 Claims.

The invention relates to signal or other flashers of the character disclosed in my applications Serial No. 546,950 filed June 26, 1931 and Serial No. 560,728 filed September 2, 1931.

The object of the invention is to further perfect appliances of this kind to the end that their functions will be improved in important particulars, and that its utilization and maintenanc may be facilitated.

A specific aim is to improve the construction of the combined transformer and electromagnet so that still greater eiilciency may be attained in the function of the transformer at the same time that the operation of the interrupter armature is carried on with efficiency.

A further object is to enable the regulation of the timing of the signal flashes in a novel and extremely simple way, obviating necessity for exposing or disturbing the operative parts, but on the contrary, permitting adjustment by manipulation of a simple rotatable member exteriorly of the case in which the complete operative unit l is enclosed.

A still further purpose is to make it possible to embody a unit of this nature using tilting switches dependent on gravity for the timing function in such manner that while being manually variable by persons without mechanical skill, they may also be mounted by unskilled persons without liability of failure to function correctly because of failure to accurately position the unit with respect to the horizontal.

Another object of importance is to present a novel mounting of a mercury tube switch specially valuable in my appliances. With this it is an important attainment that I have evolved a leadin connection of novel kind minimizing liability of short circuit or failure by wear, and enabling the connecting of such a switch in its circuit in an extremely simple and economical manner, as to production of parts and their assembly.

Additional objects, advantages and features of invention are involved in the construction, arrangement and combination of parts involved in the embodiment of the invention, as may be understood from the following description and accompanying drawing, wherein,

Figure 1 is a cross section of a complete unit, case and mounting, full size, with a slow speed interrupter.

Figure 2 is a rear View of the unit with the case broken away, showing the use of a high frequency interrupter.

Figure 3 is an enlarged vertical section through the hanger and adiuster.r

Figure 4 is an enlarged longitudinal section of the tube mounting and lead-in construction.

Figure 5 is an enlarged rear view of the tube and mounting with the spring support broken away.

Figure 6 is an'enlarged front end View of the tube and mounting.

Figure 7 is a. diagram of the electrical circuits.

'I'here is illustrated an operating unit I0, for an electric sign flasher, particularly utilizing discharge tubes for its illumination, such as the neon units now commercially well known, although other lamps or devices operating on other principles may also be controlled or operated by my device.

This unit is adapted to be suspended from a hook or pin on any proper support, as the back of a sign which is to be operated, or a single hook or bracket forming a xed part of the sign or other structure may be employed, if desired, as will be readily understood.

This unit includes a cast oblong base or frame I2 of aluminum or other non-magnetic metal including a bottom plate I3 slightly wider than the transformer coils involved in the device, and slightly longer than the laminated core of the transformer. Over this base and covering all parts of the unit there is a hood-like case I4 of sheet metal the lower edge of which is continuous and snugly fits around the plate I3. A

The case is closed throughoutl except for apertures adjacent certain threaded terminal sockets or junction fittings into which terminal lugs may be screwed without removing the case, to connect the device to the service and control leads, and one aperture at the top through which a suspension stud I5 projects by which the device is suspended, as will be more particularly described.

The plate I2 has two parallel longitudinal iianges I6 from which there are continued at each end respective pairs of upstanding arms I'I the flanges and arms forming together medially of the plate a channel and mounting for a core I8 which is set snugly between the flanges and arms and held by bolts I9 engaged through the arms I1 and core. The core comprises two sets of opposed and alined E-shaped laminated core sections, all of the blanks being of uniform size and shape, and closely fitted to each other throughout. The ends of the arms of the two cores are in abutment so as to form substantially continuous members, and I have found it important to insure a good pressure of the opposed members into contact. At the upper side of the top arm of the core the junction is bridged by a top plate L3 having flanges downturned on each side of the core and secured thereto by bolts 2l. Centrally this plate the stud l5 is fixed, its axis being as nearly as practicable coincident with the center ci gravity ci the' whole unit. The stud is exterioriy threaded at its base and also intermedioi' its length, with an intervening interrupwhile the upper extremity is reduced and with a diametrical slot 22 opening on upper end in a 'vertical plane at right angles to the major plane of the armature cores. A suspension link 23 or hanger 23 stamped from heavy sheet metal is fitted and connected pivotaily in this slot, by means of a pin 24 engaged through the two side portions of the stud and across the slot spaced as far as practicable from the ei the stud. vThe slot extends below the pin distance and the lower end of the link is ed with bill 25 projecting from the slot at the side opposite the pin. The aperture in the "op the case `fits snugly around the stud and case is retained in place by a nut 25 engaged on the lower part of the stud and pressing the case upon the plate 28. A errule nutV 2l is enen the upper 'threads of the stud having a nge fitting close around the reduced part el' 1 stud so as to engage the upper side of the when screwed down thereon. It will be rstood from foregoing that with the fer- Li'l at its uppermost position, when the unit suspended from the link, it will be inclined 'transversely downward toward the side opposite the pivot Sill, while if the ierrule is screwed down on the bill 25 this inclination may be lesscned or the unit inclined the opposite way.

The iront flange i6 is interrupted rnedially of length two pivot lugs 2B formed thereadjacent through which a pintle 29 is engaged supporting an armature movable transversely cere immediately adjacent the plane oi' abutment or" the core arms but nearer one end than the other so that the armature is actually e out of the plane of abutment.

armature is formed of soft iron lamina- -is and includes a lower body portion beside delle leg 3l or" the core, its lower end rethe pintle loosely therethrough a distance above the loi/er end of the armature, to provide en arm 32. The upper end is bifurcated and extended 'to a sullicient height to engage a cushion znatelal at the side of the top leg S4 of the core ai l held under the ange or" the top plate which is notched to permit engagement of the armature with this cushion.

The frame l2 is provided with a standard 35 through the base o which a screw is engaged c a weak compression spring 3l bearing against the arm 32 'to hold the armature body retracted. The upper part of the standard has a stop screw engaged therethrough having a ccshioned end engaging the armature to check movement away from the cores.

etween the bifurcations of the armature there pivoted a switch lever 39 which is formed of sheet nieta-l having an upper part bent into U- shape in cross section to forni two parallel ears lili which are apertured to receive a bushing 4l through which there is engaged a pivot pin :i2 fixed across the furcations ci the armature so as te support the lever above the middle leg of the Vbraided or tinsel wire O2 is engaged through th core. Beyond the ears toward the core the lever is shaped as a split tube 3 with clamp ears il receiving a clamp screw therethrough by which the tube may Le clamped on a close coiled helical spring 46 inserted in the extremity of the lever. This spring I have formed of steel wire, nt ne outer end of the lever 39 an arm fil is extended downwardly adjacent the inner side of the standard 35 and arranged to engage a cushion niaterial 3 on the standard, which material may rubbei'.

The coil Q5 carries at its outer end a mercury switch This includes a tube indrical elongated form projecting longitudinally from the coil d6 and having the usual sealing tit 52 at the outer end, and at its base end having a vattened lug part projecting til-refrein through which electrodes 5d are engaged, having contact points or electrodes projecting inte and within the space within the tube, as well tending outward from the tube for connection with suitable current leads.

An important detail to note is that the lug is arranged in a vertical plane, and the electrodes are spaced one above the other, whic' li culiar advantage in my device over horizontally because of greater certainty of br-x ing circuit, although they may be spaced transversely at the end or sides of the tube. The tube is mounted at the extremity of the spi by inea-ns of a wire cradle frame 55 which may be formed integrally with the spring QG. The cradle is formed with a loop 55 at the outer end over the tit and from the loop side members 5l extend parallel in supporting relation to tube, to the inner end thereof, where each side in ber is formed with an upwardly bowed part F33 engaged snugly against the respective side of the lugs 53. One side of the cradle is continued directly from the spring as a continuation oi' the wire of which it is formed, while the return end of the wire at the opposite side of the cradle is welded or soldered directly to the helical part of the spring thereadjacent, The helical tremity of the spring is concentric with the lower electrode and may be insulated in that relation by means of beads 5i) of insulating material loosely arranged in helices and engaging the electrodes. The bows 58 are linked and electrically connected to the upper electrode as at tu, adding to the security of the tube in the cradle frame. In the tube there is a globule 5i of mercury. e tube as ordinarily used in this construction is less than twice the vertical dimension wl "h the body of mercury tends to assume by its larent surface tension when at rest on the lower side of the tube; and the upper electrode at position to engage the globule when in this forni adjacent the innerend of the tube. Beads 5G are l.l cated at intervals throughout the length of and within the spring ll-, and a very tine strand of se beads and electrically connected to the lower electrode 54. The beads are continued en the wire outwardly of the lever 39 a suitable disiance.

In one section of the core a primary coil 54 is mounted around the middle leg of the core, while in the opposite section a secondary coil G5 of greater dimension longitudinally is mounted. One end of the primary coil is connected to the wire G2 while the other end of this coil be connected to the battery 56 or other eactrieal source, the opposite terminal of the battery being grounded on the frame I2, completing the circuit to the switch through the spring 5. The

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secondary 65 has its ends connected to respective ends of a neonr tube 86.

The spring 4S is proportioned in strength to the weight of the tube and mercury so that a considerable oscillation of the tube occurs when the amature Il) is attracted by the magnet. As indicating the action of the spring, if it were detached and held, with the tube very slightly inclined upward from the electrode end, with the mercury in contact, if pressed downward, the weight of the mercury shiftingto the outer end of the :tube is suflicient to cause the tube to remain in this open circuit position. The formation of the cradle parts and securing of the spring in the lever 39 make it desirable to usea wire which will not be liable to deformation easily, and for that reason I have ordinarily used a ring stock somewhat thicker and-stronger than necessary, and have ground of! a portion of the spring, midway between the lever sleeve 43 and the tube 49 as indicated at 63, producing a medial part of the spring of exceeding exlbility, adapted to produce the peculiar effects desired.

One terminal of the secondary is connected to a junction-fitting 81 mounted on a plate of insulation mounted at one end of lthe frame |2, the other end of the secondary being grounded on the frame. The wire 63 is connected to one end of the primary 64 while the other end of the primary is connected to a second junction fitting mounted like the first at the opposite end of the frame.

With the commotion presented a signal utilizing a neon tube or other high tension electrical manifestation may be produced from the energy of a one and one-half volt source (a neon tube of 56 inches length and one-half inch diameter has been so operated) at intervals ranging from one-fifth of a. second or less to more than one full second, and by lengthening the mercury tube much longer intervals may be secured. The device is specially adapted to be operated from a single commercial dry cell, and has operated continuously at something less than one second intervals for a period of over thirty days on a single cell without change.

At one end of the plate I3 an upstanding lug 69 is formed integrally thereon in which vertically spaced apertures 10 are formed. This provides a mounting for an alternative switch structure by which flashing at much shorter intervals is practicable than obtainable with the switch SII and its mounting (see Fig. 2). This comprises a simple spring wire 1I having one end portion inserted through the upper aperture 10, then recurved and inserted in the lower aperture and secured. The wire extends parallel to the core Il to near the far end of the unit from the lug 69, and has mounted at its extremity a mercury switch 12 comprising a tube similar to the one 49, but having its lower electrode connected to the spring electrically and having the insulated exible lead 13 to the upper electrode from one terminal of the primary 64. The previously described switch mounting including the lever 39 may be removed, and an arm 14 is connected to the lower part of -the armature 30, extending beneath the middle leg 3| of the core between the primary and secondary windings and over the wire 1I, arranged to strike the wire when the armature is attracted to the core I8. The mercury tube in this switch is adjusted at more of an upward inclination from the electrodes and the globule of mercury engages and disengages one or both electrodes in such manner when the arm 14 strikes the' central part of the wire spring 1 I, as to rapidly make and break the circuit by reactions of the spring for a considerable time without further actuation by the arm 14. The reaction of the spring causes it to strike the arm and rebound a number of times on each operation of the armature. The frequency of these oscillations is greater than the period of charging of the coil 64 to the degree necessary to operate the armature, and as the oscillations subside, the mercury finally comes into such relation to the contact at the upper electrode that a sustained contact is formed sufllcient to produce an operation of the armature, when the action is repeated. Each of the frequent interruptioms thus produced in the earlier stage of the oscillations of the spring after each operation of the arm 14, causes a high tension discharge from the secondary across the neon tube, but without the drain on the source of energy that would be required to operate the armature 30. A high frequency interruption of the primary circuit sufclent to produce the necessary high tension current for actuating the neon tube is thus secured with operation of the armature at comparatively long intervals, and with resultant economy of current from the source. For this form of interrupter, the link 23 and slot 22 should be arranged longitudinally of the core I8 instead of transversely, and by its use the inclination of the switch 12 may be adjusted to produce the desired frequency of interruption. The wire 1| is less exible than the spring 46 and there is not produced the same degree of movment of the tube as at the switch 50 nor the same simple movement.

In the operation of the device of Figure 1, the device being assembled as described and connected as indicated by Figure '7, when the armature is attracted toward the core, it moves into engagement with the cushion 33 by which it is silently checked. The movement is abrupt enough and in a direction to produce a substantial element of motion horizontally in the mercury, projecting it toward the outer end of the tube after movement of the armature is checked. Initially, in overcoming the inertia of the mercury, the latter is caused to press into the electrode end of the tube, banking around the electrodes, and preserving a very positive closure of the circuit during the time the armature is moving toward the core, insuring the loading of the I primary fully to secure the full magnetic effect possible before the circuit is broken by separation of the mercury from the electrodes. During the movement under energization of the coils, the arm 41 swings backwardly, permitting the tube 49 to swing downward rapidly: by gravity and also momentum imparted, the mercury being moved from the electrodes to the opposite extremity of the tube and causing the tube to move to an extreme lowered position by momentum, ilexing the spring 46. The circuit having been broken in this movement, the armature swings back by action of the spring 31 and by engagement of the arm 41 against the cushioned upper end of the standard 35 the lever 39 is returned to initial position abruptly. This puts the spring 46 under additional stress and in its reaction it flicks the tube 49 upwardly to a maximum high position, the tube continuing to oscillate then by the action and reaction of the spring 46 in such a manner that centrifugal force acting toward the outer end of the tube retains the mercury there, delays its return until the oscillations diminish to only a slight movement. the mean incline of the tube causing the mercury to move then by gravitation toward initial position again. The Weight of the mercury in the outer part of the tube also lessens the mean inclination of the tube so as to delay return movement of the mercury, and makes it easier for the oscillations to keep the mercury from returning.

In case it is desired to make the interval of inte ruption longer, the ierrule nut 2l is unscrewed to decline the unit toward the outer end of the tube, and to shorten the interval an opposite adjustment is made. Also the initial position of the nature may be adjusted by screw 38 with soieiect on the inclination of the tube and action of the armature.

As each contact is made in the primary circuit the coil 5d becomes loaded, building up the magnetic iiux, and in the resultant break of the circuit the fall potential generates a high tension current in the secondary, which is suficient to discharge across the el ctrodes of the tube 66. In this way an extremely small voltage current is employed to actuate a neon tube with high efnciency.

It is to be noted that the formation of the two core ections into a unit with the ends of opposing legs merely in abutment instead of having laminations oi the opposed members overlapped, and operating an armature thereat is a departure from usual practice, and results in enabling the utilization oi the transformer also as a magnet notwithstanding that-the core is substantially continuous, cii'ecting a substantial economy over the practice in which a separate magnet is employed to operate the armature switch. It is also important to not-e that the armature isin a position at the time of circuit interruption to overlap the junction oi the core sections and cause a coniinement of the to the path through the windings, and this is at the instant when the inductive action oi the device is manifest. Thus, no energy is used to operate the armature at that time, but all may be directed to the production of the illuminating current.

assurance of a good tight contact of the opposed core sections avoids excessive vigor in the action oi the armature, and causes a sufficiently positive operation which projects the n ercury from closed circuit position without breaking the globule. Maintaining the globule unitary results in a very uniform intermission of contact. fast operation the mercury does not move all the way to the outer endof the tube, while on an adjustment for slow timing the mercury reaches the iai' end of the tube, causing greater range of oscillation, as well as giving a greater "'istance for the mercury to travel on its return to contact position, both oi which are material in the timing action attained. If the ends of the core sections are separated the armature will be more powerfully drawn and the mercury globule may disrupted, causing iregularity in the timing or even double contacts on its return.

Timing may also be lengthened by increasing compression ci the spring 3l against the arm 33, opposing magnetic response of the armature 30, and this also may be utilized to secure higher magnetic loading of the primary coil to some eX- tent.

With respect to the device using the spring 1I, it may be pointed out that variations of eiect of the device may be secured by varying the position of the end of the spring with respect to the horizontal. Thus if the spring be inclined upward at its outer part the operation Will tend to cause ilexure actions of the spring tending to hold the mercury outwardly from the contacts over several oscillations, after which the diminishing activity of the spring causes rapid make and break effects until subsidence of the mercury sufficiently to make the longer Contact that will actuate the armature again. Thus there would be produced an intermittent series of closely following llashes with a time interval of substantial period between the last Contact or one series and the iirst contact of the next series of flashes.

In a primary coil such as utilized in Figure l to induce a high tension current in the secondary to illuminate a neon tube with high eillciency, an appreciable period of time is involved in securing the building up of the lines of force around the primary (called'here loading) to the maximum, and a simple oscillation device such as a vibrator spring, or immediately esponsive armature switch, is not adapted to form the closed primary circuit for a surlicient period to secure an eiicctive result. invention overcomes this deficiency by reason of the fact that closing of the primary circuit in which the tubes 3l and 32 are included as shown in Figure ll. causes projection of tho tube longitudinally in the direction opposite the electrodes or contacts. The inertia of the mercury causes it to bank and press .into the impacting end ci the tube so as to secure not only high efliciency in contact, but retaining the contact throughout the movement of the armature toward the magnet, delaying the opening or breaking or' the circuit for a sui'licient period to build up a maximum loading effect in primary coil. It results in the highest possible potential in the induced current being attained. On the other hand, the period during which it necessary to hold the circuit closed for full loading is still very brief, and a simple tilting mercury tube contact will close the circuit for an unnecessarily long period, while my device opens the circuit so quickly after closure that wasted energy in maintaining the primary closed circuit after the necessary loading period is minimized. The period of closure may be made proporti nate to the loading period without materially varying the period of intermission by adjusting the initial position of the armature. The period of intermission may be regulated by adjusting the whole device so that the initial inclination of the tubes is and by using longer or shorter tubes, or increasing the ilexibility of the arms GE--GS to secure longer period of oscillation producing centrifugal By forming the spring E of steel wire, and using this wire for the cradle 55, when the c* l ture 30 is actuated and the lever sv s ow.i wardly, the cradle of the tube is broufit into the iield of the middle legs 3! of the core i8 adjacent the abutment of the two core a result the cradle will be magnetically increasing the deflection of the spri of Je 49, increasing'the effectiveness of the action. of the switch in a peculiar way. In tbe globule should have become disrupted ant divided, and one part should adhere to the contacts, the increased declination thus obtained wil separation from the contacts of the adhering p and its union with the other part of the globule, and continued operation of the device vafhereas, if an adhering part of the globule should l 'm and not be dislodged, the circuit would remain closed and the switch cease to function for the time until started in some special way.

I claim:-

1. In a device of the character described, an

electromagnetic field device, a yieldingly retracted amature responsive thereto, a switch lever pivoted on the armature having a vertically oscillatable part, a spring projected from the swinging end of the lever, and a tube projecting longitudinally from the spring having contacts at its inner end and inclined upwardly therefrom, a globule in the tube, said tube and spring being adapted to oscillate vertically in a substantial degree whereby to hold the globule at the outer end of the tube in opposition to action by gravity, for the purposes described.

2. In a device of the character described, a mercury switch comprising an elongated receptacle, electrodes in the receptacle, a support for the receptacle attached thereto and projecting from one end of the receptacle consisti of a helical spring having an intermediate portion of reduced strength, and including flexible electrical connections for the electrodes.

3. In a device of the character described, a switch comprising a lever, a highly flexible spring on the lever and extended therefrom distant from the pivot, and a tube receptacle at the extremity of the spring containing a globule of mercury and adapted to oscillate on an axis and over an arc having its center adjacent the longitudinal axis of the tube, to produce centrifugal force in the mercury, and Contact means in the tube to be connected by the mercury at one position of the mercury.

4. In a device of the character described a switch comprising a lever, a highly flexible helical spring extended therefrom, a tube of insulating material having a tit at the outer end and a flattened longitudinal lug at the opposite end, one end of the spring being extended and looped over the tit, its intermediate portion being formed as a cradle for the tube and secured to the lug, a globule of mercury in the tube and contacts therein at one end.

5. In a device of the character described, a switch comprising a lever having its outer part formed as a split sleeve, a highly flexible helical spring longitudinally slidable in the sleeve, a tube receptacle mounted at the extremity of the spring, a globule of mercury in the receptacle, contact means in the tube arranged to be connected by the mercury at one position of the mercury and means to clamp the sleeve on the spring.

6. The structure of claim 3 in which the spring is a helix, the said contact means consisting of electrodes exposed in the tube and extended exteriorly of the tube, the spring being secured to the tube in line with one electrode, an articulated tubular insulation means Within the spring and a flexible conductor extended therethrough to the alined electrode.

7. 'Ihe structure of claim 3 in which the spring is a helix, the said contact means consisting of electrodes exposed in the tube, electrical connection between one electrode and the spring in a tube-supporting relation, and a flexible electrical conductor extended from the other electrode 1n insulated relation within the spring.

8. The structure of claim 3 in which the spring is a helix, one of the contacts of the switch having a ilexible electrical conductor extended therefrom axially through the spring, and a multiplicity of separate annular insulating members engaged loosely upon the conductor loosely disposed within and supported by the spring.

9. In a device of the character described, an electromagnetic device including a coil and a movable armature, a switch lever pivoted thereon, a stationary member adjacent the armature and spaced from the coil, said lever having an arm extended at an angle therefrom between the coil and stationary member to engage the stationary member on movement of the armature, and a tilting switch carried by the lever.

10. The structure of claim 9 in which said switch includes a spring extended from the lever, and a tube-receptacle containing a mercury globule at the outer part of the spring and having a predetermined normal inclination in initial position.

ROBERT R. GONSE'IT.

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