US2339675A - Switch - Google Patents

Description

Jan- 18, 1944- H. E. BUCKLEN, JR., ,Eru.` 2,339,675

SWITCH Filed May 3, 1941 2 Sheets-Sheet 1 Jan. 18, l944.- H. E'. BUcKLEN, JR.. Erm. 2,339,675

swITcH Filed May 3, 1941. 2 sheets-sheet 2 Patented Jan. 18, 1944 SWITCH Herbert Erucklen; Jr., Elkhart, Ind.,and Joseph Klotz, Chicago; Ill.; said Klotz assigner to said Bucklen Application May 3, 1941, Serial No. 391,682

19 Claims.

This invention relates to switches, and more particularlyv is cncernedwith the manufacture of a switch structure for use in connectionwith the startingof three-phaseV electric motors or the like.

Heretofcre,- three-phase motorA starters were of relatively bulky, cumbersome types having open air contacts and being mounted in alarge metal box or the like for support, and consisted of a multiplicity of'open air contacts which were exposed to corrosion, pitting and rusting.

The present invention contemplates an extreme departure from this type-of motor starter in that all-of the movable operating parts of the motor circuit are housed within a metal envelope which is capable of being evacuated and then lled with a hydrogen gas under` pressure so that the contacts are disposed in a hydrogen atmosphere, which will prevent them from corroding or oxidizing and will maintain themv clean and bright, thereby reducing the contact resistance and insuring long life for the switch.

In conjunction with such a structure, we preferably employ an armature within the envelope having a supporting stem uponiwhich are mounted atV axiallyspaced intervals contact bridge members, preferably floatingly arranged to` bridge across contacts disposed in insulated re-f lation within the enclosed structure. The contacts are respectively connected through conductor rods to external terminals mounted in circumferentially spaced relation at one end of the relay or switch, and a suitablel thermal overload protection mechanism isembodied in the terminal end of the relay for protecting the circuit against overloads. By protecting at least two of the phases against overload, itis apparent that the entire circuit is protected.I

In the assembly of such a'structure, ametal envelope having an enlarged tubular portion is provided in which is seated a series of ceramic or refractory insulators arranged in axiallyspaced relation, and each provided with recesses in which are housed contact members adapted to be controlled by an armature suitably arranged in one end ofthe envelope and having an extending stem upon' which are supported the contact bridging members. Surrounding the reduced end of the envelope adjacent thearmatureis a magnetic coil which, when energized, shifts the armature axially to eiect closing of the circuits simultaneously to the three phases ofthe motor. The construction lends itself Well to a nal enclosing ofr the entire mechanism within a molded l insulating case? dr shell-4 through which the terminal conductors extend to the various conductor rods leading to the contacts; and which also provides for completely insulating and weatherproong the entire assembly.

Another feature of the present invention is the incorporation of vauxiliary units within the enclosure. This comprises the auxiliary retainer switch associated with the three-phase contacts. Also arranged for support in axially spaced relation to these parts of thethree-phase motor switch is a thermal overload switch connected between thel line in suchl manner that the second and third phases are subject to the control cf this switch, which is preferably of the magnetic thermal type, that is, theV switch is magneticallyy held closed until such time as the thermal capacity of the magneticv elements reaches a point Where they lose their paramagnetic characteristics and the switch then opens automatically due to such overload, thereby opening the circuit. Preferably, this is provided by employing permanent magnets, which in turnv are adapted to be engaged by thermal elements of the type known asfCurie-Point metal, such as Int/ar, which, under normal temperatures, have magneticV characteristics that will retain the permanent magnet in contact therewith, but under overload, the elements heat up to a pointvv where they losetheir magnetic characteristics and the permanent magnet contacts drop therefrom, thereby opening the circuit.

ln the present construction, we preferably provide for an effective sealing of the metal enclosing shell by the use of rubber gaskets which are compressed axially to cause radial expansion thereof for sealing the same to the interior surface of the shell and about the axial face of theA outermost ceramic block. The gaskets are compressed and held in positionby means of an insulating compression member that is retained by the spun-over edge of the open end of the envelope.- AtV the closedend oil the envelope a tubulation is provided, which may` be connected to a source ofV vacuum and then to a source of hydrogen gas under pressure for evacuating and subsequently filling the interior of the envelope Withhydrogen gas under pressure, after which the tubulaton` is sealed, thereby retaining the hydrogen under pressure within` the envelope and surrounding all of the contacts.

Other objects-and advantages of the present invention will appear more fully from the following detaileddescription which, taken in conjunction with the accompanying drawings, will disclose to those skilled in the' artthe particular construction and operation of a preferred form of the present invention.

In the drawin-gs:

Figure 1 is a vertical sectional view through a switch structure embodying the present invention;

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

Figure 3 is a similar sectional view taken on line 3-3 of Figure 1;

Figure 4 is a corresponding sectional view taken on line 4 4 of Figure 1;

Figure 5 is a corresponding sectional view taken on line 5-5 of Figure 1;

Figure 6 is a sectional view taken on line 6-6 of Figure 1; and

Figure 7 is a diagrammatic showing of a control circuit embodied in the present switch.

Referring now in detail to the drawings, we

have provided a metal shell 5 which may be formed of an austenitic steel or the like, and which preferably is provided with a reduced end portion 6 and an enlarged elongated tubular body portion 1. Surrounding the reduced end portion 6 of the envelope is a magnetic coil 8 which may be held in position in any suitable manner, as by means of the external insulating cover 8 preferably formed of a molded product, such as Bakelite or the like,

Disposed within the envelope 5 adjacent the small end thereof is a ceramic spacer member I8 which has a frusto-ccnical end portion seated against the irusto-conical shoulder I2 joining the reduced portion 6 with the enlarged portion 'I of the envelope. at I3 to provide room for an armature I4 which is preferably of slightly smaller diameter than the end 6 of the envelope, and is adapted for axial reciprocation upon energization of the coil 8 moving upwardly to an actuated position against the rubber stop I5 located in the closed end of the envelope. The rubber stop is provided with a suitable recess I6 within which is biased one end of a coil spring I1, the opposite end of this spring extending into the recess I8 of the armature and seating against the base of the recess, whereby the armature is normally biased toward inoperative position. The spacer member II) is provided with an axial bore I9 therein through which extends an insulating stem 2i) connected to the armature by means of the split rings upon opposite sides of the base of the armature.

The rings are preferably engaged in grooved portions formed in the stem 0n opposite sides of the base portion of the armature, whereby the stem is locked for conjoint movement with the armature in each direction.

The outer radial face of the spacer I0 is provided with a gasket member 22, which may be formed of any suitable insulating material, such as nber or the like, against which is biased a second ceramic block 23 provided with the axial recess 24 opening toward the spacer member I0. The member 23 is provided in its inner radial face with arcuate recesses adapted to receive the contact terminal members 25 and 26, respectively. Each of these members is provided on the under surface thereof about the inner periphery with a contact portion preferably formed of coin silver or the like indicated respectively at 27 and 28. Mounted on the stem 20 within the recess 24 is a contact assembly comprising a supporting member 29 having a depressed center portion adapted to be biased upwardly by means The spacer I0 is recessed as f of a spring 30. The member 29, which may be formed of a plate or similar stamping, is provided with upstanding arm portions 32, which in turn carry between the bifurcated ends thereof a contact bridging member 33. This member is provided with contact surfaces 34 and 35, respectively, of coin silver adapted, when the armature is in raised position, to engage the contacts 2l and 28 for closing the circuit therebetween. The spring mounting of the plate, plus the clearance of the plate relative to the post 20 provides a universal support which allows floating of the contact bridge member 33 into position to provide uniform pressure between the contact surfaces 21-34 and 28-35.

Suitable split rings 36 mounted in grooves in the post 20 retain this contact assembly against axial sluiting, and insure its conjoint movement with the post. It will be noted that the recess 24 is closed at its outer axial end by the radiallyl inwardly extended ange portion 31 of the insulating spacer 23, which is suitably bored to provide for reciprocation of the post therethrough. Disposed on the outer radial face of the member 23 is another gasket 22 against which is biased another ceramic or insulating spacer member 38 provided with the recess 39 within which is disposed a contact assembly 40 corresponding to that carried by the post 20 within the recess 24. This includes a contact bridging member 42 adapted to have bridging contact engagement between the terminals 43 and 44 of a second pair of contacts whereby, upon energization of the coil 8, the member 42 will bridge to complete a circuit between the contacts 43 and 44.

It will be noted the member 38 is substantially identical with the member 23 except that the arcuate recess in the inner face thereof for receiving the contacts 43 and 44 is varied, the contacts 43 and 44, as indicated in Figure 3, having ear portions 45 and 46, respectively, recessed into the face of the member 38 with their upper surfaces lying against the gasket 22.

Disposed against the gasket 22 on the outer radial face of the member 38 is a corresponding member 48 provided with the recess 49 in which is disposed another contactl assembly 40 corresponding to the previous contact assemblies and having the contact bridging member 5I provided with contact surfaces adapted to engage the contact surfaces 58 and 52 of contact terminals 53 and 54, respectively. Each of these terminals 53 and 54 is provided with ear portions 55 and 56, respectively, recessed in the upper face of the member 48 and disposed in angularly offset relation with respect to the ear portions of the contacts 43 and 44.

The post 20 continues axially through the member 48, and another suitable gasket 5I is interposed between the outer radial face of the member 48 and another insulating spacer member 51. The member 51 is provided with a reduced tapered axial extension 58, and also is provided with a reduced recess 59 opening upwardly toward the member 48. Mounted on the post 20 within the recess 59 is a contact bridging member 60 having contact points engageable with the contacts 62 and 63 of contact terminal members 64 and 65, respectively. The bridging member 68 is mounted on the post 2D provided with a universal support, and is held against axial movement on the post by means of split rings in the same manner as the contact members 48. At its lower end the post 20 is provided with longitudinal grooves 61 and is guided'A intov a cup member 68, which formsV astop for limiting downward movement ofthe armature and postassembly. Asuitable rubber gasket 59 is placed against the outer radial face of the spacer member 5l, and is provided with a peripheral flange or skirt 'l0 extending into the annular case around the reduced portion 58 of the spacer 51. The cup member 66 is preferably provided with a radial flange '|2', which is engaged by the gasket te for holding the cup in position.

vA second gasket l3is provided, which is the same as the gasket 69 but is turned in the opposite direction, both of the gaskets being formed of resilient material such as rubber or the like. The ilange or skirt portion l74 of the gasket 13 extends around the reduced extension 'l5 of an insulating member 16, which may be formed of Bakelite or similar insulating material. The member 16 is provided with a reduced cylindrical extension 'l1 forming a shoulder 16 adapted to yreceive a retaining washer 19, which washer is engaged by the spun-over end 8U of the envelope.

It willbe apparent that when axial pressure is applied against the member 16 urging it axially inwardly of the envelope 5, corresponding movementis effected on the gaskets 69 and 'i3 and on the spacing members 51, 48, 36, 23 and It. The gaskets are radially expanded to provide a positive seal with the internal surface of the envelope and about the cup member 58, thus providinga moisture and gas proof seal rfor the open end of the envelope. While the members are heldin compressed position, the end 8|] of the envelope is spun over to lock the same against displacement.

tion, the tubulation 82 at the closed end of the envelope isconnected to a suitable source of vacuum for withdrawing all gases and moisturefrom the interior of the envelope.v The tubulation 82 is then subsequently connected to a source of hydrogen gasunder pressure andthe gas is forced into the interior of the envelope, lling all the cracks and recesses therein. With the pressure maintained, the tubulation is pinched closed and welded, thus sealing'. the hydrogen gas under pressure within the envelope.

Considering now the connections of the various contact terminals, reference is had vto Figures 2 to 5, inclusive. The contact terminals 25 and 26 between the spacer members I and 23 are adapted to receive axially extending terminal rods 90 and 92, respectively, which extend through the spacermembers, 38, 48, T and 16, and are connected at their outer ends beyond the end. of the envelope 5 to suitable conductors, such as indicated at 94.

Similarlyy the contact terminals 43 and 44 have the wing portions 45 thereof connected through terminal rods 95 and 95, respectively, to terminal conductors, the rods 95 and 96 extending axially through the spacer members 38, 48, 5l and 16, the lower end of the terminal rod 95 being indicated as connected to the conductor 96' at the outer end thereof. It will be noticed that the rods d5 and96 are axially offset from the rods 9U and 92 so that they are spaced apart by the insulation of the spacingmembers. In a similar manner, the wing portions 55 and 56 ofthe contact terminals 53 and.. 54 are'connected through terminal rods 91 and.98 tov suitable conductors disposed at the outer` end ofthe envelope. The outer ,endof, the. memberr 16.' isi provided with ends' `ofy the Various terminal rods terminate, andthese-recesses receive the terminal conductors:

The terminal contacts 6d and 65, as shown inA Figure 5, have terminal rods |00 and |62 extending'axially through the spacer members 51 and i6, the rods terminating at the outer end of the member 'I6 and being thereconnected to suitableconductors, as will be described hereinafter.r

Referringl again to Figure l, a suitable cap member |63l is provided at the lower end of the member lt, and is adapted to be secured thereto by the screws iM which have their head portions countersunk into the insulating plate member |05, closing the outer end of the cap member m3. Supported-in the plate member lll-5 is a reset button |06 having a head portion |01 adapted to engage a contact bridging member |09 forming a part of a thermal overload switch. The member |66 is normally biased outwardly by means of the spring H6 bearing against the washer H2 carried on the stem portion of the button. The contact bridging member |69 comprises an insulating plate carrying the contact bridge H3, which is provided with contact portions engageable with the contacts 4 and ||5 respectively, to close the circuit therebetween. The contact H5 includes a connector ||6 which, at its opposite end, is connected to the terminal |66 of the contact terminal 65. The opposite contact lill is connecte-d through the conductor ill to the terminal end of the terminal rod 95, whereby it is directly connected to the conductor 96', as indicated clearly in Figure 1. The insulating plate lil@ is also adapted to carry at the opposite ends thereof U-shaped permanent magnets, which are indicated more clearly in the ldiagrammatic showing in Figure 7 by the reference numeral |26. The magnets |26 are adapted to engage suitable terminals |23 which, in this form of the invention, are preferably formed of Invar, which has the characteristic of changing from a paramagnetic character to a diamagnetic character at 200 degrees centigrade. The timing feature for such an overload device in terms of current is controlled by the cross section of the strip of Invar |23, whereby it will be `heated to the critical temperature when an overload exists in the main line circuits. Upon reaching this temperature, the magnetic action between the magnets |26 and strips |23 is released. This results in the member |69 dropping down into position on the head l (il of the reset button,

breaking the contacts between the bridging member I3 and the contacts l i4 and l l5.

The terminal rod H32 of the contact 61E is connected through the conductor |25 to a lead-in connection |26, which in turn extends to the start and stop control for the switch, indicated diagrammatically in Figure '7, there preferably being a fuse |28 interposed in this line.

Considering Figure 'l in more detail, it will be noted that both the contacts M and 54 which are connected to the load side of the switch have connections to the overload release contacts |23,

whereby the current flowing to the load side'of the switch passesr through the Invar strips |23 so that in case of overload, these` strips will loseV radially outwardly directed recesses in which the Y their paramagnetic character and release the switch |09. The contact 25 is connected through the terminal rod 90 to a conductor |30 which in turn has a branch connection |32, indicated in Figures 2 to 5, leading to one side of the coil 8. 'Ihe opposite side of the coil 8 is connected through conductor |33 to the terminal |34 controlled by the Contact bridging member |35 of the starting and stopping switch. It will thus be seen that the coil is energized through these two conductors which extend through suitable recesses formed in the insulating case 9 surrounding the switch. This case preferably has a threaded end cap |35 for closing the lower end thereof, which cap is provided with a recess forming a guide for the button |06. Similarly, the enclosing case 9, as shown in Figure 5, is provided with radially opening ports or passageways |36 through which suitable conductors are extended to the various terminal posts. The conductor 96 is provided with a branch conductor |31 which leads to the contact |38 of the start button |39 for energizing the switch.

In the operation of the device With the circuit as shown in Figure 7, the switch is energized. Upon pushing the button |33, the circuit is closed by the contacts |38 and |46 of the start-stop control switch, thereby allowing current to iiow from the line conductor |30 through conductor |32 and coil 3, and thence through conductor |33 to lcontact |34 which is bridged by the button |35, thus completing a circuit through the coil, raising the armature M, and closing the contacts 25-26, 43-44, 53--54 and Eli-55. This transmits current through the starter switch from the supply side or the line to the load side, the current on the load side in the second and third phase passing through the Invar strips |23. The switch |08 normally being closed, there is a closed circuit extending from conductor 955 through terminal post 95 which has the branch connection leading to contact lii of the overload switch. From the contact bridging member ||3 of this switch the circuit is extended through contact i and conductor i5 to contact 55 over the bridge 60 to contact Sd, and thence through conductor to the contacts lf2-3.

Interrupting the connection between contacts |34 and |40 by pushing the oiT" button to lift bridge |35 provides an interruption of the coil circuit, thereby deenergizing the same and allowing armature I4 to drop, which opens the switch and stops the motor. The motor will also stop whenever` the thermal overload switch is tripped, causing interruption of the coil circuit at contacts |I4, II5.

While the moto-r may be normally started or stopped by means of switch buttons |39 and |35, it can be started after an overload has tripped switch |03 only by manual resetting of the overload switch by button |36.

While it is obvious that the circuit arrangement could be varied in any desired manner, the present invention is directed more-particularly to the details of construction of the switch mechanism itself, and it is believed that this mechanism enclosed within a metal envelope with the contacts disposed in an atmosphere of hydrogen gas under pressure provides a very novel and distinctly advantageous starter switch construction.

We are aware that various changes may be made in certain details of the present construction, and therefore do not intend to be limited except as defined by the scope and spirit of the appended claims.

We claim:

1. In combination, an elongated tubular metal envelope of non-magnetic steel having a reduced closed portion at one end, a magnetic coil disposed about said closed end of the envelope, a series of vertically stacked insulated spacer blocks in said envelope including means forming recessed chambers therebetween, spaced pairs of contact terminals in each of said chambers formed by said spacer blocks, an armature in the closed end of said envelope adapted to be operated by said coil, a non-metallic stem on said armature extending axially through said blocks, contact bridging members axially spaced on said stem and operative to close contact between said respective pairs of terminals upon actuation of said coil, and means for sealing the open end oi said envelope, and individual terminal connectors extending axially through said blocks to each of said terminals.

2. The combination of claim 1 wherein said connectors extend outwardly through the open end of said envelope in circumierentially spaced relation.

3. In combination, an elongated tubular metal envelope having a reduced closed end, an in sulator seated against the shoulder forming said reduced end and having an axial recess opening into said end, a magnetic coil surrounding said end, a reciprocatory armature in said end and recess, a plurality of axially arranged insulating blocks in said envelope having axial bores and enlarged axial recesses in one face thereof, an insulating stem secured to said armature and extending through said blocks, pairs of contacts disposed in each of said recesses, and contact bridging members on said stem within each of said recesses for closing the circuits between said contacts upon energization of said coil, and terminal connectors for each of said contacts extending outwardly through the opposite end of said envelope,

4. The combination of claim 3 further characterized by the provision of compressed resilient sealing means closing the opposite end of said envelope and having pressure sealing engagement about said connectors.

5. The combination of claim 3 further characterized by the provision of means applying axial compression to said sealing means at the opposite end of said envelope, and a iilling of hydrogen gas under pressure in said envelope retained therein by said sealing means.

6. The combination of claim 3 further characterized in that the said projecting ends of said connectors are arranged circumferentially, and terminal conductors are connected thereto externally of said envelope.

7. In a three phase motor starter switch, a tubular metal envelope oi' austenitic steel having an elongated reduced closed end, axially spaced pairs of insulated contacts in said envelope, each pair forming part of one phase circuit, a reciprocable armature in said envelope having axially spaced contact bridging members, an actuating coil surrounding the closed end of said envelope and adapted to move said armature in one direction for closing the circuits between said pairs of contacts, spring means biased against the closed end of said envelope for urging the armature in the opposite direction, an insulating seat 1n said end for said spring means having an axial bore, and a tubulation at said end opening into said bore for evacuating said envelope.

8. In a three phase motor starter switch, a sealed tubular metal enclosure, an actuating coil surrounding a portion thereof, insulating means stacked axially in said enclosure and having recesses forming insulated switch chambers between said insulating means, a pair of contacts for each phase circuit of said switch disposed in said chambers in axially spaced relation, a terminal connector to each contact extending axially outwardly of one end of said enclosure, magnetically responsive means in said enclosure carrying contact bridging members for closing the circuits of said phases upon energization of said coil and resilient sealing means for said envelope compressed about said connectors.

9. The switch of claim 8 including means for urging magnetically responsive means to circuit open position upon deenergization of said coil.

10. The switch of claim 8 further characterized in the provision of an insulating block extending outwardly of said enclosure and having recessed portions forming individual pockets for connecting conductors toy said terminal connectors,

11. The switch of claim 8 further characterized in the provision of an insulating block extending outwardly of said enclosure and having circumferentially spaced radially recessed portions forming individual pockets for connecting conductors to said terminal connectors.

12. A motor starter switch comprising an elongated tubular metal envelope having a reduced closed end, a spacer seated against the shoulder dening said reduced portion and having an axial recess facing said end, an armature reciprocatory in said end and recess, a series of axially stacked insulating blocks in said envelope having alined axial bores and each having a recess defining a contact chamber, terminal members having spaced contacts in said chambers, a stem on said armature extending through said bores and having bridging members carried thereon in each recess for engaging said spaced contacts upon actuation of said armature, and a coil surrounding said reduced portion for actuating said armature.

13. A motor starter switch comprising a sealed tubular metal envelope, a plurality of insulating blocks alined axially in said envelope and having an axial bore therethrough, an armature reciprocatory axially in one end of said envelope and having an insulating shank projecting through said bore, each of said blocks having a radially enlarged axial recess at one face thereof defining contact chambers, a pair of arcuate contacts in each chamber, the contacts in respective chambers being offset circumferentially, terminal conductors extending axially through said block to each of said contacts and projecting in circumferentially spaced relation out of the end of said envelope, means surrounding said envelope for actuating said armature, and means in each of said chambers carried on said shank for bridging the contacts in said chamber upon actuation of said armature.

14. In a motor starter switch, a non-magnetic tubular metal envelope closed at one end, an armature axially reciprocable in said end having an insulating axially projecting shank carrying axially spaced contact rings, a series of axially spaced contacts supported in insulated relation in said envelope with the respective contacts of each series circumierentially oiset relative to those oi adjacent series, a series of circumferentially spaced terminal conductors connected to the respective contacts and extending axially outwardly of the open end of said envelope, means engaging about said terminal members and sealing the open end of said envelope, and an insulating block carried by said open end of said envelope having circumferentially spaced radial recesses to provide for conductor connections to said terminal members.

15. In a motor starter switch, a sealed metal envelope having a reduced closed end, a coil surrounding said end, an armature axially reciprocable in said end and having an extending insulating stem, a series of insulator stacks in said envelope having alined axial bores through which said stem extends, said stacks having enlarged recesses about said bores forming spaced switch chambers, a pair of contact members in each chamber, axially spaced contact bridging members on said stem for engaging said contacts upon energization of said coil, resilient sealing means engaging one end of said stacks, insulating compression means axially forced into position to compress said sealing means for closing the opposite end of said envelope, and iiange means on said opposite end of said envelope locking said compression means in position.

16. The switch of claim 15 including an insulating molded cup-shaped case receiving said envelope, and a molded cap member closing said case.

17. The switch of claim 15 including connector posts extending axially from each of said contacts outwardly through said sealing means and compression means,

18. The switch of claim 15 including connector posts extending axially from each of said contacts outwardly through said sealing means and compression means, and arranged in circumferentially spaced relationship, said compression means having radially directed recesses for the outer ends of said posts providing for lateral connection of terminal conductors thereto.

19. A motor starter switch comprising a sealed metal envelope having a reduced closed end, a shoulder between said end and the main body portion of said envelope, an insulator member in said envelope seated against said shoulder and having an axial recess opening into said end, axially spaced pairs of contacts in said envelope disposed in insulated relation below said member, an armature axially reciprocable in said end and recess having a shank carrying axially spaced contact bridging members for said contacts, a resilient insulating bumper in the closed end of said envelope limiting movement of said armature in one direction, said bumper having an axial bore therethrough, and a tubulation fitted into said end of said envelope and opening into said bore for evacuating and filling said envelope with gas.

HERBERT E. BUCKLEN, JR. JOSEPH KLOTZ.

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