US2543768A - Transfer switch for high-frequency heating systems - Google Patents

Description

March 6, 1 951 c. E. ELLSWORTH ET AL TRANSFER SWITCH FOR HIGl-LFREQUENCY HEATING SYSTEMS Filed Aug. 20. 1947 4 Sheets-Sheet 1 4 m s Q B A .1. ML mh M E. w Q m\ \h NR ouwpv nh %h V mw 3 Wu R R hm MN Q w MN 8mm. Mm V vw INVEN TORS Gun 5. [LLSWGRTH A TTORNEVS March 1951 c. E. ELLSWORTH ET AL 2,543,768

TRANSFER SWITCH FOR HIGH-FREQUENCY HEATING SYSTEMS Filed Aug. 20. 1947 4 Sheets-Sheet 2 Km w 5 A M w T Q N s E u w i \M f L R ww Q Mw h NM wh mh Wk hm 0H. N1 QM. m\ ms mh F 5 /4/? THUR E. 6/; 55/? 7' B) A TTOR/VEVS March 1951 c. E. ELLSWORTH ET AL 2,543,768

TRANSFER SWITCH FOR HIGH-FREQUENCY HEATING SYSTEMS Filed Aug. 20. 1947 4 Sheets-Sheet 5 x/wgrv TORS CARL f. Z45W0RTH ARTHUR /LBERT B) ATTORNEYS March 6, 1951 I C.'E. ELLSWORTH ET AL 2,543,768

TRANSFER SWITCH FOR HIGH-FREQUENCY HEATING SYSTEMS Filed Aug. 20, 1947 4 Sheets-Sheet 4 mug/v TORS CARL 5 LCZLSH/G/FTH A TTOR/VEVS Patented Mar. 6, 1951 TRANSFER SWITCH FOR HIGH-FREQUENCY HEATING SYSTEMS Carl E. Ellsworth, Louisville, and Arthur E. Gilbert, near Louisville, Ky, assignors to The- Girdler Corporation, Louisville, Ky., a corporation of Delaware Application August 20, 1947, Serial No. 769,698

14 Claims.

-1 a This invention relates to transfer switches of the type particularly applicable for use with highfrequency heating systemsand hasfor an object the provision of a transfer switch which is rela tively compact, rugged in construction, easily operated, and which insuresthe completion of circuit connections with a minimum of electrical resistance.

In the application of electrical energy to dielectric materials for the generation of heat therein, a

relatively high voltages and frequencies are utilized. For example, the voltage may be of the order offroni 1000 to 50,000 volts with a frequency of the order of. from 1,000,000 cycles per second to 10,000,000 cycles pe second, and above. Since the heating effect is proportional to. the square of the voltage and directly to the frequency, it is desirable for any given installation to utilize high, optimum values of frequency and voltage. This ineans thatthe voltages involved, without provision of safety features, are dangerously high. The conductors are ordinarily of relatively large size and, in general, are included inconcentric lines.

As. explained in Zottu Patent 2,419,307, a transfer switch is essential if a high-frequency gen.- erator is utilized to supply energy to more than one load for the reason that the very size of the conductors makesdific-ult, if not impractical, the manual connection and disconnection of such conductors from one load toanother. The transfenswitch of said Zottu patent while satisfactory, leaves something to be desired in compactness, ease of operation and, the development of desired contact pressures.

In carryin out the present invention in one form thereof, there is provided in circular array around a common center a plurality of stationary contacts respectively connected to various loads to be supplied with high-frequency energy. A centrally located movable contact may be fluidcooled through internally located flow channels, the contact-engaging portion itself consisting of a spherical contact movable into and out ofengagement with concave surfaces of each of the stationary contacts and presenting to each a dif ferent contact surface; Preferably, a toggle mechanism or equivalent is utilized to develop high-contact pressures and to eliminatesliding friction during movement from one circuit-controlling position to another. The high-vo1tage movable contact is isolated from the operating mechanism by a plurality of insulators and is cnnected by aflexible conductor, including a plurality of Sylphon bellows, to the incoming line from the high-frequency separator.

For further objects and advantages of the in vention, reference-is to be had to the following descriptiontaken in conjunction with the accompanying drawings, in-whichthe transfer switch has been illustrated together. with a grounding arrangement which forms the subject matterof. a copending application filed. by Austin .Proctor, also-worker of ours, on .AugustZO, 1947, Serial No. 169,660.

In the drawings:

Fig. l is a sectional elevation of a transfer switch embodying the invention;

Fig. 2 is a sectional view takenonthe line.2.-- of Fig. 1;

Fig. 3 is a fractional view similarto Fig. l but with the parts in an open circuit position;

Fig. 4 is a view taken on the line 4-4 of Fig. 1; and

Fig. 5 is an isometric View of the switch illustrating the manner in which the operating handle projects from the. enclosinghousing.

Referring to the. drawings, the invention inone' form has been shown as; appliedto. atransfer switch comprising a movable contact I0. which; in its preferred-form is-provided withcu-rvedcontact surfaces lea- Asshown, the movable contact It is hollow and spherical, with the. lower: end thereof provided with a stud l l extendingthrough an arm l2 and secured in place bya. nut, l3 located on theouter threaded .end thereof. The arm l2 extends from a. supportingmember or bracket. l4 having'a conical or concavesurface Ma to form a line contact with the. ball-shaped movablecontact I0. The stud H is loosely dis-.' posedwithin theopening inxthe arm [2 so that when the supporting member or bracket [4115 moved to the right. against themovable contact it, the concavesurface. l4a,;is pressed againstit. In Fig. 1 th movable contact *is illustrated in one circuit-controlling position for transfer to energy from a flexible conductor through movable contact lil'and a-stationary contact l6, by way of the innerconductor l'l'of a concentric line to a selected 'load (not shown) connected thereto. The outer conductor [8 of the concentric line is connected to the housing [9 of the switch, which housing may include angle-supports and 2| fromwhich there'extend insulators 22 and 23 for supporting the stationary-contact IS. The stationary contact Iii-is also provided with a concave or conical surface l6a which also provides line contact with theball-shaped movable contact l0.

The flexible conductor [5 is'hollow and is made flexible by forming itfrom a series of Sylphon bellows, only four of which, the 'bellows,24'2l, are shown. The conductor-Isis secured atone end to a connector l5c and'forms an extension from the inner conductor 29 of aiconcentric line, having an outer conductor 30.. The conductors '29 and 30 are directly connected to the output terminals of the high-frequency generator. The

conductor 29 is of course secured to connector 15c. The movable'contact'lo may be operated into and out of engagement with any selected one of the stationary contacts by means of an operating handle 3| which includes an actuator 32. To isolate the movable contact ID from the operating handle 3|, a plurality of insulators, such as insulators 33, 34 and 3Yin' triangular arra extend between the bracket l4 and a bracket or member 36 secured to theend of an actuating rod 3']. The rod 31, supported in bearings 38 and 39, is connected to one end of a link 40 of a toggle mechanism, the other link thereof being formed by an extension of the handle 3| which, it will be observed, is pivoted by a screw 42 extending through a bracket 43. With the toggle in the straightened position-as shown in Figs. 1 and 2, there will be developed a very substantial force pressing the movable contact In into line contact with the stationary contact l6. Upon pressthe latch actuator 32, a latching arm 44 is withdrawn from beneath a part of a rotatable frame or turntable 45. The operating handle 3| may then be moved upwardly, as viewed in Figs. 1, 3 and 5, to rotate its toggle-extension downwardly to break the toggle. This movement moves the rod 3'! to the left to withdraw the movable contact ID from engagement wth the stationary contact l6. 'As this movement occurs, an arm 35a extending from the member 36 rotates an actuating rod 46 in a clockwise direction around its pivotal support 41. When this occurs, a compression spring 48, acting on a collar 49 secured to a rod 50, moves the rod to the left through its guides 52 and 53 to rotate a grounding contact arm 54 about its pivotal support 55.

The lower end of the arm 54 has a pin 56 extending through it and into a slot 51 formed in an adjustable member carried by the rod 5|]. The grounding arm 54, Fig. 4, is provided with four sets of contacts. The pair of contacts 58, upon clockwise rotation of the arm 54, engage the'grounded outer conductor I8, Fig. 3, of the concentric line, while the pair of contacts 59 resiliently form a wiping engagement with the inner conductor Thus, as the movable contact It! disengages the stationary contact 16, the inner conductor ll of the concentric line and the housing I?) is grounded in avoidance of all hazards to the operator at the load which is being disconnected from the high-frequency generator.

It will be observed that each of the remaining stationary contacts is provided with similar grounding arms 54 together with their associated contacts and that these are in positions for grounding each of the inner conductors of the lines extending from the transfer switch. By reason of these provisions, maximum safety is attained inasmuch as the interruption of the grounding connection can occur only when there is deliberate operation of the handle 3| to connect a particular concentric line and load to the high-frequency generator, as to the suppl conductor 29.

. It has already been mentioned that the movable contact I!) may be fluid-cooled for some applications of the invention. If air be introduced through a flexible tube 6|] for producing a blast of cooling air against the hollow inner surface of movable contact H], with exit thereof around the outer surface of the flexible tube 60, the resulting air pressure within the bellows 24-28 may tend to elongate them. Accordingly, it is preferred that there be provided one or more tension members to resist elongation of the flexible con- 4 ductor 5. Preferably the flexible tube 69 is so constructed as itself to resist elongation. For example, it may include either as an integral part thereof or separately therein tension members such as a cable 6| which resist elongation without materially decreasing the flexibility of conductor l5 about the axis of the inner conductor 29. It is further contemplated that the tension members themselves may extend between the movable contact I0 and the connector |5c carried by the supporting plate 62 into which the flexible conductor I5 is also secured as by the screws 53. The tension-resisting elements may be utilized with or without cooling of contact l0 and whether or not a liquid be used as a cooling medium in place of circulation of air, or other cooling gas.

Thus far there has been described the operation of the switch from its position illustrated in Figs. 1 and 2 to the position illustrated in Fig. 3.

After the operation of the switch to the opencircuit position illustrated in Fig. 3, the movable contact In may be rotated into engagement with any selected one of the stationary contacts. For example, the handle 3| may be lifted from its position shown in Figs. 1 and 5 upwardl and out of an indexing recess 64 and thence along a circumferential slot 65, Fig. 5, formed as a part of the housing I9 until it coincides with another indexing slot, such as one of the slots 67a, 68a and 63a. Thereupon the handle 3| is moved downwardly to straighten the toggle and to move the contact I0 into engagement with the corresponding one of associated stationary contacts 61, 68 or 69, shown in Fig. 2. Of course, any other position may thereafter be selected for operation of the switch.

The movable-contact assembly, Fig. 1, including the turntable or frame 45, is rotatably supported on a subframe ID by means of a bearing H of the frame 45 which receives a bearing member 12 extending upwardly from the subframe 10. A further indexing mechanism is provided by a spring 13 which urges a ball 74 into recesses 15 formed in the upper plate of the subframe 10 in positions corresponding with the locations of the stationary contacts.

Each of stationary contacts |6, 61, B8 and 69 is mounted on the inner conductor of a concentric line, the outer grounded conductors 76, ll, 18 and 19 of which are shown in Fig. 2.

It is, of course, to be understood that interlock contacts will be provided, so that immediately upon upward movement of the operating handle 3|, or upon releasing movement of the latch actuator 32, the high-frequency generator will be deenergized. Such interlock contacts are conventional, and, therefore, have not been illustrated; see for example the interlock contacts N9 of the aforesaid Zottu Patent No. 2,419,307. Besides personnel protection, it is intended that the high-frequency generator shall always be deenergized before operation of the selector switch in order to avoid any arcing between the movable contact ||J and any selected stationary contact.

In the operation of the switch from one circuitclosing position to another, it is to be observed that the movable contact l0 will rotate relative to the bracket l4 and its supporting arm II. This is particularly advantageous since such relative rotation will bring into registry with each stationary contact a different contact-engaging surface of the curved movable contact l0. Thus,

wear on the movable contact ID will be distributed 5. over a substantial part of the curved surface thereof. This advantageous result isbrought about by the pivotal mounting of the movable contact HI- on the arm I2 and by reason of the fact that the flexible conductor I5 does not turn or twist about its center line. In other words, it assists in producing the relative rotary motion of the contact In relative to the arm l2. flexible conductor 15 need not be formed of' a plurality of Sylphon bellows since any flexible conductor may have one end attached to the:

connector I50 and may extend downwardly toward the circular array ofstationary contacts 16, 61-, 68 and 63,, and thence outwardly and in.

spaced relation with the plane thereof, and thence downwardly to the movable contactv l0. With such a. flexiblev conductor, as I5, the movement. of the free end thereof to whichthei contact; I is secured describes an are having a radius some what less than that of the circular array of stationary contacts. The flexible conductor I not only provides for the circular motion but also for the radial motion during movement of contact In: into and out of engagement with. a selected stationary contact.

While a preferred embodiment of the invention has been illustrated, it isto be understood. that further modifications may be made without. departing from the scope of the appended claims.

What is claimed is:

1. A transfer switch comprising a plurality of stationary contacts laterally spaced one from the: other, a movable contact, a bracket for support-- ing, said movable contact for rotation relative to said bracket, actuating. mechanism for moving said bracket to move said movable contact intoand out of engagement with a selected. stationary contact, a flexible conductor having. one end secured to said movable contact'and having its opposite end anchored in spaced relation thereto, said flexible conductor being efiective to produce.

relative rotation between said stationary contact.

and said bracket.

2-. A transfer switch comprising. av plurality of stationary contacts laterally spaced one from the other, a movable contact, a bracket for support-- ing' said movable contact for rotation relative to said bracket; actuating. mechanism for moving said bracket to move said movable contact. into and out of engagement with a. selected stationary contact, a hollow flexible conductor having lateral flexibility but resisting rotary movement. about the EtXis. thereof, one end of said flexible conductor being secured to said movable contact, supporting means for said conductor spacedifrom said movable contact and said bracket, said conductor resisting rotation thereof to bring different areas of said movable contact. into engage.- ment with each of said. stationary contacts.

3;. A transfer switch comprising a plurality of stationary contacts. laterally spaced one from the other, a hollow spherical movable contact, a bracket for supporting said movable: contact for rotation relative to said bracket, actuating mechanism for moving said bracket to move said movable contact into and out of engagement with a selected stationary contact, a hollow flexible conductor of construction providing lateral flexibility but resisting rotary movement about the axis. thereof, one end of said, flexible conductor being secured tosaid movable contact and resistingv rotation thereof to; bring difierent areas of. said movable contact into. engagement with each of. said stationary contacts, and; a flexible fluid conextending lengthwise of said flexible, con.

The

ductor for flow of a coolant into and out of said hollow contact in heat exchange therewith.

4. A transfer switch comprising a sperical movable contact, a plurality of stationary contacts spaced one from the other in circular array around said movable contact, means including an operating mechanism rotatably supporting said movable contact for movement into alignment with any selected one of said stationary contacts, said operating mechanism including means connected to said movable contact for moving it generally radially toward and away from a selected stationary contact and for developing high contact pressures when said movable contact engages astationary contact and for relieving that pressure as said movable contact disengages a stationary contact, said operating mechanism including a pivotal support for movement of said:

mechanism and saidmovable contact from one: stationary-contact position. to another, and aflexible conductor connected to and movable with said movable contact but which resist rotation about. its own axis to produce relative rotation. between. said movable contact and said operating mechanism as the. latter is moved from one stationary contact position to another to present different areas of said movable contact to each of said stationary contacts.

5:. The combination set forth in claim 4 in which each of said stationary contacts is provided with a conical surface for engagement by said movable contact and said operating mechanism is provided with, a pressure-applying member having a conical surface for engaging said: movable contact.

6. A transfer switch comprising. a plurality of stationary contacts spaced one from the other in a common plane and in circular array about a common axis, a supply conductor spaced outwardly from said common plane of said stationary contacts with the adjacent end thereof substantially concentric with said common axis, a flexible conductor connected at one end to said adjacent end of said supply conductor and extending'both axially toward and radially outward from said common axis to a point adjacent to, but within the radius of, said circular array of said stationary contacts, a movable contact, having aspherical contact surface, connected to the free end of said flexible conductor, operating mechanism, means supporting said mechanism for rotation about said common axis, said opcrating mechanism including insulating means interposed between said axis and said movable contactfor electrically insulating the latter from the remainder of said mechanism but serving as a. mechanical connection between said movable contact andsaid remainder of said mechanism, the disposition and flexibility of said flexible conductor providing for movement thereof. with said.

movable contact about said circular array of stationary contacts.

7. A transfer switch comprising a plurality of. stationary contacts spaced one from the other in circular array about a common axis, amov-- able. contact, each of said stationary contacts and. said. movable contact having curved contactengaging surfaces for nesting relation one With the other, a pivoted supporting member having spaced: guides, an actuating member carried by said guides and slidable with respect thereto in. directions normal to said axis; means including said actuating member for supporting said. movable contact and for moving. it into and out of abutting: engagement-with. a. selected stationary contact, an Operating handle pivotall connected to said supporting member and to said actuating member for rotating said supporting member and said rnOVable contact from one to another of said stationary contacts, a flexible conductor directly connected at one end to said movable contact, and means supporting aid flexible conductor in spaced insulated relation with said pivoted support and from said actuating member for movement of said end with said movable con-- tact from one to another of said stationary contacts.

8. A transfer switch comprising a plurality of stationary contacts spaced one from the other in circular array about a common axis, a movable contact, each of said stationary contacts and said movable contact having concave and convex contact-engaging surfaces for nesting relation one with the other, a pivoted supporting member having spaced guides, an actuating member carried by said spaced guides and slidable with respect thereto in directions normal to said axis, means including said actuating member for supporting said movable contact and for mov ing it into and out of abutting engagement with a selected stationary contact, an operating handle pivotally connected intermediate its ends to said supporting member, a link the respective ends of which are pivotally connected to one end of said operating handle and to one end of said slidable actuating member to form a toggle for rotating said supporting member and said movable contact from one to another of said stationary contacts, a flexible conductor directly connected at one end to said movable contact, means supporting said flexible conductor including its other end in spaced insulated relation with said pivoted support and from said actuating member for movement of said end with said movable contact from one to another of said stationary contacts, an indexing member having a slot to receive said handle when said movable contact is in alignment with a selected stationary contact, said movement of said handle into said slot straightening said toggle to move said movable contact into nesting relation with said selected stationary contact and to apply substantial contact pressure thereto, said handle upon being lifted from said slot breaking said toggle and withdrawing said slidable member and said movable contact from engagement with a stationary contact preparatory to rotation of said movable contact into alignment with another selected stationary contact.

9. A transfer switch comprising a plurality of stationary contacts spaced one from the other in circular array about a common center, a movable contact having a curved contact surface, operating mechanism for moving said movable contact into and one of engagement with a selected stationary contact and when out of engagement with a selected contact for moving it from one stationary contact to another, means supporting said operating mechanism for rotation about an axis extending through said center and normal to the plane of said circular array of stationary contacts, means for connectin said movable contact to a source of supply comprising supporting means spaced outwardly from said plane of said stationary contacts and substantially in alignment with said axis, said means including a flexible conductor extending downwardly toward said plane and outwardly in spaced relation with it and into conductive relation with said movable contact, said operating mechanism including means for rotatably supporting said movable contact generally in said plane of said stationary contacts, and means including said conductor for holding said movable contact in fixed relation with respect to said flexible conductor for presentation of different surface areas thereof to each of said stationary contacts when operated into selected engagement therewith.

10. A transfer switch for high voltage, highfrequency electrical energy comprising a plurality of stationary contacts spaced from each other in circular array around a common center, a supply connector for a supply line spaced outwardly from the plane of said stationary contacts and substantially concentric with an axis extending normal to said plane and from said common center, a flexible conductor connected at one end to said connector and extending toward said plane, thence outwardly thereof and in spaced relation therewith, and thence downwardly to a point near said plane, the free end thereof being radially within said circular array of stationary contacts, a movable contact of spherical shape connected with said free end and disposed in said plane, means including a bracket supporting said movable contact for rotation with respect thereto, said bracket and each of said stationary contacts having conically shaped surfaces for line contact-engagement with said movable contact, insulating means supporting and extending from said bracket towards said center, a turntable rotatable about said axis, and operating mechanism carried by said turntable and connected to said insulating means for actuation of said movable contact into and out of engagement with a selected one of said stationary contacts and rotatable with said turntable for rotation of said movable contact from one selected stationary contact to another selected stationary contact, said conductor restraining said movable contact for relative rotation with respect to said bracket to bring a different contact surface thereof opposite each of said stationary contacts.

11. A transfer switch for high-voltage highfrequency electrical energy comprising a centrally disposed input conductor forming the inner conductor of a high-frequency electrical concentric line, a movable contact, a frame mounted for rotation about an axis substantially concentric with that of said inner conductor, actuating means carried by said frame, said actuating means having an insulated bracket rotatably supporting said movable contact in electrical isolation from said frame, said actuating means also having an operating lever extending diametrically outwardly from said actuating means for rotating said frame, said actuatin means and said movable contact from one circuit-engaging position to another, said actuating means including a toggle mechanism for developing high-contact pressures between said movable contact and an associated stationary contact, and a flexible conductor connected at one end to said inner conductor and at its other end to said movable contact, said flexible conductor including a plurality of Sylphon bellows to impart flexibility thereto for all directions of movement resulting from movement of said movable-contact structure from one stationary contact to another and into and out of engagement therewith.

12 The combination set forth in claim 11 in which said movable contact is hollow, and in which said flexible conductor includes fluidtransmitting means for flow of a stream of cooling fluid into heat exchange relation with said movable contact, and thence outwardly therefrom for minimizing rise in temperature thereof.

13. A transfer switch comprising a movable contact and at least one stationary contact, means including an operating mechanism rotatably supporting said movable contact for movement into alignment with said stationary contact, said movable contact being hollow, a hollow fluidconducting flexible conductor connected to said movable contact for flow of current thereto, and a fluid-conducting conduit disposed within said hollow conductor for flow of cooling fluid directly into heat exchange relation with said movable contact for cooling the same and outwardly therefrom in the space between said flexible conductor and said conduit disposed therein.

14. A switch comprising a movable contact of spherical shape, a plurality of stationary contacts in circular array around said movable contact, each of said stationary contacts having a conical circuit making surface, an actuating member rotatably supporting said spherical contact and having a conical surface for engaging said spherical contact, means for moving said actuat- 10 ing member to bring itsv conical surface into diametral alignment with said spherical contact and the conical surface of a selected stationary contact, and means attached to said spherical contact for producing relative movement with respect to said actuating member for a different diametral alignment through said spherical contact for each circuit making position thereof.

CARL E. ELLSWORTH. ARTHUR E. GILBERT.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS

Images