US2833873A - Multi-pole tap switch construction for changing transformer taps under load - Google Patents

Description

JANSEN MULTI-POLE TAP SWITCH CONSTRUCTION FOR May 6, 1958 B.

CHANGING TRANSFORMER TAPS UNDER LOAD 4 Sheets-Sheet 1 Filed Dec. 26, 1956 ll z n l //////////M May 6, 1958 Filed Dec. 26, 1956 @mf w fwn B. JANSEN MULTI-POLE TAP SWITCHACONSTRUCTION FOR CHANGING TRANSFORMER TAPS UNDER LOAD 4 Sheets-Sheet 2 CHANGING TRANSFORMER TAPS UNDER LOAD Filed Dec. 26, 1956 4 Sheets-Sheet 5 B. JANSEN May 6 1958 MULTI-POLE TAP SWITCH CONSTRUCTIQN FOR May 6 1958 lwww1-POLE TA1? 'svirasgqsmucnorq FOR 2,833,873

CHANGING TRANSFORMER TAPS UNDER LOAD nited States Patent MULTI-POLE TAP SWITCH CONSTRUCTION FOR CHANGBG TRANSFORMER TAPS UNDER LOAD Bernhard Jansen, Regensburg, Germany Application December 26, 1956, Serial No. 63l,598

Claims priority, application Germany January 7, M56

32 Claims. QCI. T200-17) lthe present invention relates to a tap switch for chang ing transformer taps or similar connections under load, particularly in connection with high voltage power circuits.

The tap switch of the present invention offers marked advantages with respect to other forms of tap switch construction presently known in the art. Advantageous features of the present switch construction include low mechanical inertia of the moving parts thereby permitting high speed switching operation; limited and reduced mechanical displacements of the movable contact members, thus prolonging contact life; wide spacing of those current-carrying portions of the switch which are at different electrical potentials, thereby rendering the switch suitable for high voltage service; and a form of construction which may be readily dimensioned to provide a desired degree of wiping action in the course of engage ment and disengagement between cooperating switch con` tacts, the amount of wiping action being selected in a particular switch construction in accordance with the frequency of Switch operation which is expected to be encountered in actual service in order to provide both maximum reliability of contact engagement andy maxiinum contact life.

A further important feature of the switch construction of the present invention resides in its compactness which is limited only by considerations of the minimum spacings required for satisfactory arc-quenching and the operating voltage of the circuit in which the switch is connected.

ln general, the switch construction of the present invention comprises a plurality of separate movable contact carriers each having a periphery formed in the shape of a circular arc, an individual contact carrier being provided for each pole of the switch.

member which is turned through a limited arc by the operating shaft of the switch. Each of the contact carriers is provided with a series of teeth dening a gear segment and all of the gear segments mesh continuously I with the teeth of a common internally toothed ring gear, thus operating as segmental planetary gears. The movable contacts of each pole are carried by a radially displaceable supporting structure comprising a group of contact arms which are spring-pressed outwardly to bring the movable Contact successively into individual engage ment with their respective cooperating stationary contacts during rotation of the operating shaft of the switch.

By arranging the radial positions of the places where engagement between the moving and stationary contacts ecurs so that such places of engagement are displaced from the pitch circle of the meshing gear teeth, a wiping Contact action can be obtained. In order to minimize contact weer, and particularly in situations where the switch is operated frequently, the places of engagement between the stationary and moving contacts may all be located substantially on the common pitch circle of the meshing gear teeth wher-c relative sliding displacement The several conr. tact carriers are all pivoted to a common rotary actuating ice between the xed and stationary contacts will be extremely slight or substantially zero.

Additional novel features and advantages of the invention will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof.

Referring to the drawings:

Fig. l is a plan sectional View of a three-pole switch embodying the invention, the portions of the switch which are shown in the three 120 sectors A, B and C being taken along the lines A-A, B-l-B and C-C, respectively, of Fig. 2, locking the respective directions of the arrows;

Fig. 2 is a frgamentary view in. sectional elevation showing a single pole of the switch of Fig. 1;

Fig. 3 is a fragmentary plan view of a single pole of the switch of Figs. 1 and 2 and which shows the meshing gear teeth which maintain the movable contacts aligned for engagement with their respective cooperating stationary contacts;

Fig. 4 is a fragmentary bottom plan view of a single pole of the `switch shown in Figs. 1 and 2, illustrating one of two springs which maintain contact pressure between the cooperating movable and stationary contact when any two such contacts are in engagement with each other;

Fig. 5 is a fragmentary view in sectional elevation showing a modified form of switch construction in which a greater number of steps are provided than in Figs. l and 2 for changing from one transformer tap to another when the switch is used for transformer tap changing and in which friction reducing means are provided in the form of pivoted link and roller members the section being taken along the line 5--5 of Fig. 6;

Fig. 6 is a fragmentary view in plan section taken along the line 6 6 of Fig. 5;

Fig. 7 is a circuit diagram showing the connections of one of the poles of the switch of Figs. 5 and 6 to a single phase transformer for tap changing the corresponding stationary switch contacts of Fig. 6 and Fig. 7 being indicated by dotted interconnecting lines; and

Fig. 8 is a circuit diagram showing a three-pole switch according to Figs. 5 and 6 diagrammatically, the stationary contacts being shown interconnected for single phase operation in conjunction with a set of current equalizing transformers for distributing the switching currents substantially equally among the three poles of the switch.

Referring to Fig. l there is shown a three-pole switch 1li embodying the invention, the switch 10 is illustratively shown connected for tap-changing service to a trans former winding 11. rThe transformer Winding 11 may be the single winding of an auto-transformer or it may be magnetically coupled to another transformer winding (not shown). The winding 11 is assumed to be one of three Y-connected transformer windings in a three-phase power distribution system, the other two windings being omitted from the drawing for simplicity of illustration. The Y-connected windings have a common neutral point 12 which is shown separately in each of the three sectors, A, B, and C of Fig. 1 in order to simplify the drawing by omitting the interconnecting wires which tie the individual neutral point connections of the three poles of the switch together.

The switch 10 is shown in Fig. l half-way between its two limiting positions. In each limiting position, the neutral point 12 is connected to one or the other of two collector bars 14 and 15. A slidable contact member 16, not adapted for switching under load, is mounted on the collector bar 14 and a similar slidable contact member 17 is mounted on the collector bar 15. The slidable contact 16 is selectively engageable with alternate tap points 19, 20 and 21 of the transformer winding 11. The other slidable contact 17 is similarly selectively engageable with other alternate tap points 23, 24 and 25 of the transformer winding 11. Thus, when collector bar 14 is disconnected from the neutral point 12, slidable contact 16 may be moved to pick out one of the tap points 19, 20 or 21 which is adjacent to whichever one of the tap points 23, 24 or 25 is connected to the load. Thereafter, the collector bar 14 may be connected to the load by moving the switch to its other limiting position, thus leaving the slidable contact 17 free of any load so that it may be moved without electrical load to select a tap point adjacent to the particular tap point which is actually under load. In this manner, by moving the switch 10 back and forth between its two limiting positions, and by alternately moving the slidable contacts 16 and 17 when contact being moved is not under load, the full range of all the transformer taps may be covered consecutively without skipping any tap. Automatic mechanism of conventional construction may be provided for this purpose, or the movement of the slidable contacts 16 and 17 may be performed manually. The transformer winding 11 is provided with a high potential terminal 27.

The switch 10 comprises a hollow cylindrical contact support 28 which is formed of insulating material. The switch 10 includes three separate poles arranged 120 apart and which are of identical construction. Accordingly, the switch construction will be described with reference to a single pole, like reference numerals being used for similar parts for each of the three poles. Each pole comprises four stationary contact members 31, 32, 33 and 34 which are mounted on the cylindrical insulating support 28 with their inner surfaces arranged along a circular arc. Stationary contacts 31 and 34 are connected directly to the collector bars 14 and 15, respectively and one or the other of these two end contacts 31 and 34 is continuously under load. The other two contacts 32 and 33 carry current only momentarily during switching from one transformer tap to another. The stationary contacts 32 and 33 are connected to the collector bars 14 and 15 through switching resistors 36 and 37 respectively.

The switch 10 comprises upper and lower circular end plates 38 and 39 (Fig. 2) respectively, in which an operating shaft 40 is suitably journaled. The cylindrical contact support 28 is secured between the upper and lower end plates 38 and 39 by bolts 42. The upper end plate 38 is provided with an integrally formed depending skirt portion 43 in which inwardly directed gear teeth are formed, thus defining an internally toothed ring gear 44, coaxial with the operating shaft 40.

The operating shaft 40 is provided with vertically spaced integrally formed upper and lower collars 46 and 47. Each of the collars 46 and 47 has three regularly spaced radial extensions or hollow arms 48 each of which servesl as a housing for a helical tension spring 50. The outer end of each tension spring 50 is anchored to a button 51 located at the outer end of each hollow arm 48. The inner end of each tension spring 50 is connected to a radially slidable upper bearing block 52 or to a lower bearing block 53, each bearing block 52 or 53 being received between a pair of confronting parallel plane surfaces formed at the inner end portion of each hollow arm 48. It will be seen that there are thus three upper slidable bearing blocks 52 each of which is located directly above a corresponding lower bearing block 53, one upper bearing block 52 and one lower bearing block 53 being associated with each of the three poles of the switch 10.

There are three vertical pivot rods 54, each associated with one of the threeV poles of the switch 10, and which extend parallel to the operating shaft 6, each of the pivot rods 54 extending between an upper one and a lower one of the slidable bearing blocks 52 and 53, respectively. Each of the pivot rods 54 is individually ynected directly to the collector bar 14.

urged radially outwardly toward the contact support 28 by two of the tension springs 50.

There are four movable contact arms 55, 56, 57 and 58 which are included in each pole of the switch 10. Each of the four contact arms 55, 56, 57 and 58 comprises an inner end portion 60, 61, 62 and 63, respectively, the contact arms to 58 being differently offset with respect to one another so that their respective inner end portions to 63 are arranged vertically along the pivot rod 54. The inner end portions 60 to 63 of the contact arms 55 to 58 of each pole of the switch 10 are all individually journalled on one of the common pivot rods 54.

The contact arms 55 to 58 are angularly spaced apart with respect to each other and they extend divergently from the pivot rod 54 toward the cylindrical contact support 28 through slots 66 formed in the outer wall 67 a cylindrical guide member 68. The guide member 68 comprises upper and lower end plates 70 and 71, respectively, which are formed of insulating material and are interconnected by the slotted cylindrical wall 67. Sector gear teeth 72 are formed in the periphery of each of the upper plates 70 and the teeth 72 of all three plates 76 mesh simultaneously with the teeth of the ring gear 44. The upper and lower end plates 70 and 71 are pivotally connected to the collars 46 and 47, respectively, of the operating shaft 40 by vertically axially aligned pivot pins 73.

The common pivotal axis of the pivot pins 73 is concentric with the arc of the sector gear teeth 72. The arc of the teeth of the ring gear 44 is concentric with the rotational axis of the operating shaft 40, the latter axis being parallel to and equidistantly spaced from the pivotal axes of all three sets of pivot pins 73. Each set of sector gear teeth 72 thus operates as a fragment of a planetary gear driven by the operating shaft 40.

The contact arms 55 to 58 extend slidably through the slots 66 in the wall 67 of guide member 68. At their outer free ends, the contact arms 55 to 58 carry movable contact members 75 to 78 respectively, each of which cooperates with and engages one of the four stationary contacts 31 to 34, respectively, in a predetermined position of rotation of the operating shaft 40. When the longitudinal axis of any one of the contact arms 50 to 58 lies in the plane defined by and passing through the spaced parallel axes of the operating shaft 40 and pivot pins 73 then the particular one of the movable contact members 75 to 78 which it carries will be urged into engagement with its cooperating stationary contact with the full contact pressure produced by the tension springs 50 which act on the pivot rod 54 through the slidable upper and lower bearing blocks 52 and 53. The contact arms 55 to 58 are electrically bonded together by flexible jumpers and are all connected to the neutral point 12 by common flexible conductors 81, a separate pair of flexible conductors 81 being provided for each of the three poles of the switch 10.

In operation, the switch 10 will normally remain in either of its two limiting positions. In one of these limiting positions, the movable contact 75 engages the stationary contact 31, so that the neutral point 12 is con- In the other limiting position, the movable contact 78 engages the stationary contact 34 so that the neutral point 12 is connected directly to the other collector bar 15. During tap changing under load, the operating shaft 40 is rotated rapidly through an arc of about to effect simultaneous transfer of all three poles of the switch 10 from one of the two limiting positions to the other.

During switching operation, assuming clockwise rotation of the operating shaft 40 as viewed in Fig. 1, the movable contact 75 remains in engagement with the stationary contact 31 until the movable contact 76 engages the stationary contact 32. Thereafter, contact pressure is transferred to movable contact 76 and the movable contact 75 disengages the stationary contact 31. This action takes place with make-before-break contact sequence. This is followed by engagement between movable contact 77 and stationary contact 33 and iinally by engagement between movable contact 78 and stationary Contact 34 in the other limiting position of the switch 10.

During the switching operation described above, the axis of the pivot rod 54 is guided by the bearing blocks 52 and 53 so that it always lies in the radial plane defined by and passing through the spaced parallel :axes of the operating shaft 40 and the pivot pins 73, the switching operation being accompanied by slight movements of the pivot rod S4 radially with respect to the circular ring gear 44. These slight radial movements are accompanied by slight simultaneous sliding movements of the contact arms 55 to 58 in slots 66 of the guide member 68. The extent o t these sliding movements is extremely small compared to the spacing or distance between adjaceirL ones of the stationary contacts 3l. to lli, and is only sutlicient to permit simultaneous engagement between two adjacent movable contacts and two adjacent stationary contacts.

It will be seen from the foregoing that the switch contacts may burn or wear away unevenly without interfering with the operation of the switch or the maintenance of proper contact pressure. Thus, although the axes of the pivot pins 73 and the vertical pivot rod 54 are shown substantially in vertical alignment in Fig. 2, there may be appreciable departures from such condition of alignment, produced by contact wear, for example without irnpairing the proper operation of the switch.

As shown in Fig. 1, the circle or cylinder on which the inner faces of the stationary contacts 31 to 34 are located, is concentric with the rotational axis of the operating shaft 40 and is of somewhat smaller diameter than the pitch circle of the ring gear 44. As a result of this difference in diameters there will be a wiping or sliding action during engagement between each movable contact and its cooperating stationary contact while the operating shaft 40 is turning. This wiping action provides a desirable self-cleaning eifect for the switch contacts. In order to reduce contact wear, the wiping action may be reduced by making the diameter of the circle on which the inner faces of the stationary contacts 31 to 34 are located more nearly equal to the diameter of the pitch circle or effective meshing circle of the ring gear 44 with the sector gear teeth 72.

The modified embodiment of the invention which is shown in Figs. 5 and 6 dilers somewhat from the embodiment of Figs. 1 to 4, described above, in that means are provided for reducing friction in connection with the sliding movements of the contact arms and the contact arms are arranged in two independently spring tensioned interleaved groups. Additionally intermediate the main contacts, upper and lower stationary contacts :are provided which are simultaneously engaged by each movable contact. At the intermediate contacts adjacent to the main contacts, the switching load is evenly divided between the upper and lower stationary contacts by means of inductively coupled current equalizers. Individual switching resistors are connected to the other intermediate upper and lower stationary contacts, as may be seen in Fig. 7. Additionally the switch contacts are springcushioned.

Referring to Fig. 5, the upper and lower circular end plates 88 and 89 of the switch 90 are both provided with inwardly directed teeth which define upper and lower ring gears 91 and 92, respectively. The guide member 94 comprises upper and lower sector plates 98 and 99, respectively, both formed of insulating material. The sector plates 98 and 99, at their outer peripheries, carry arcuate members 100 and 101 which are provided with sector gear teeth 102 which are in mesh with the internal teeth of the ring gears 91 and 92.

There are a total of six contact arms 103 to 108. each of which is suspended by a swinging connection including a vertically elongated link 110 depending from the upper arcuate member 100.` The contact arms 103 to 108 are divided into two groups of three. A iirst group comprises the contact arms 103, 105 and 107, the second group comprises the contact arms 104, 106 and 108. The inner ends of the contact arms of the first group are all pivotally connected in vertically spaced relationship to a lower vertical pivot rod 111. rhe inner ends of the contact arms of the second group are all similarly connected to a. common upper vertical pivot rod 112.

The upper pivot rod 112 is movably connected to an upper collar 114 integrally formed on an operating shaft 115, this movable connection being effected by means of a pivoted link member 116. A free end portion of the link member 116 is co-nnected to the upper pivot shaft 112 while the other end of the link member 116 is pivot- :ilv connected to the under side of the upper collar 114. 'The lower pivot shift 1111'. is similarly moi/ably connected to a. lower collar 1.a integrally formed, on the switch operating shaft by a lower link member 117. The adjacent ends of the upper and lower pivot rods 112 and 111 spaced apart and are separated from each other by a disc 119 formed of insulating material and mounted on the operating shaft 115.

The upper and lower sector plates 98 and 99 are pivotally connected directly to the upper and lower collars 114 and 118 by means of upper and lower pivot pins 120 and 121, respectively, so that the sector plates 98 and 99 together with their attached toothed arcuate members 100 and 101 operate as planetary sector gears in the manner described above in connection with Figs. l to 4.

There are upper and lower spring housings 123 and 124 which are integrally formed with the llanges 114 and 118, and these spring housings 123 and 124 extend radially outwardly from the switch operating shaft 115. Helical tension springs 125 are disposed in the spring housings 123 and 124. The outer ends of the springs 125 are fxedly secured to the outer ends of their respective spring housings 123 and 124. The inner ends of the tension springs 125 are connected individually to separate collars 127 and 128 mounted on the upper and lower ends of the upper and lower pivot rods 112 and 1 11, respectively. The upper and lower spring connecting collars 127 and 128 are disposed above and below the free end portions of the upper and lower link members 116 and 117 respectively, these free end portions being shaped to engage and support the vertical pivot rods 111 and 112 both above and below the inner ends of each of the two groups of contact arms 103-105-107 and 104-106- 108. Thus, the free end portion of the upper link member 116 comprises upper and lower portions 130 and 131 rigidly interconnected by a vertical bar 132. The inner end portions of the contact arms 104-106--108 of the second group are embraced between the upper and lower portions 130 and 131 of the free end portion of the upper link member 116. The inner end portions of the contact members 103-105-107 of the first group are similarly arranged with respect to the free end portion of the lower link member 117.

Intermediate their ends, the contact arms 104 to 107 are guided between vertically extending hollow rollers 134 which serve to reduce sliding friction accompanying radial movements of the contact arms. The rollers 134 extend between the upper and lower arcuate members 100 and 101. Theend contact arms 103 and 108 are each 4guided between a roller 134 and one of two main contact bars 135 and 136, respectively.

The main contact bars 13S and 136 are rigidly connected to the upper and lower toothed arcuate members 100 and 101, and these in turn are connected 'by suitable means (not shown) to a neutral point such as the neutral point 12 of Fig.Y l. The main contact bars 135 are 136 movable main contacts 137 and 138, respectively which engage spring-cushioned stationary main contacts 139 w'P' and 140, each in one of the two limiting positions of the switch.

Each of the contact arms 103 to 108, at its free end, carries a set of four spring-cushioned contacts arranged as two double contacts, the sets of four contacts being designated 141 to 146 for the contact arms 103 to 108, respectively. In Fig. 5, the four contacts on contact arm 106 are designated 148 to 151.

There is a group of twelve individually insulated stationary spring-cushioned double contacts designated 153 to 164. The twelve contacts are arranged in two rows, with contacts 153 to 158 in the upper row and contacts 159 to 164 disposed in thelower row each directly below one of the contacts in the upper row.

As shown in Fig. 5, the stationary contacts 156 and 162 which cooperate with the movable contact set 144 carried by contact arm 106, comprise separate contacts 165 to 168 each of which is engaged by one of the movable contacts 148 to 151 respectively.

In Fig. 7, the upper row and lower row contacts 153 and 159 are both shown connected to the main stationary contact 139 through a current equalizer 169- having two inductively coupled windings 170 and 171. At the other end of the two rows of stationary contacts, the stationary contacts 158 and 164 are similarly connected to the main stationary contact 140 through a similar current equalizer 169. The current equalizers 169 distribute the switching burden evenly between contacts 153 and 159, or between contacts 158 and 164, as the adjacent main contacts are disengaged or about to be engaged. v

All of the other stationary contacts 154 to 157 and 160 to 163 are individually connected, each to one or the other of the two main stationary contacts 139 and 140 through a separate switching resistor 173. The collector bars 14 and 15 are connected directly to the main stationary contacts 139 and 140 in a manner similar to that shown in Fig. l. In Fig. 7, however the drawing has been simplied by omitting the several transformer tap points and the slidable contacts 16 and 17 on the collector bars 14 and 15, only two taps being illustrated. Additionally the double contacts 153 to 164 are diagrammatically shown as single contacts.

It will be observed in Fig. 6, that the diameter of the circle upon which the stationary contact members 153 to 164 are arranged is substantially equal to the common pitch diameter of the upper and lower ring gears 91 and 92. Accordingly, there will be little or no wiping action at the contacts during operation of the switch.

The manner of operation of the switch construction of Figs. 5 and 6 is similar to that of the switch construction of Figs. l to 4., except that two of the contact arms, such as 103 and 105 of the first group, may effect a makebefore-bre'ak switching operation while the contact arm 104 of the second group remains in continuous contact with its cooperating stationary contacts. This is possible because of the independent mobility of the vertical pivot rods 111 and r112. Thus, there will always be contact by contacts associated with at least two adjacent ones of the contact arms 103 to 10S, with short intervals where three or possibly four of the contact arms are active.

Referring to Fig. 8, a three-pole switch having the construction shown in Figs. 5 and 6 is illustrated, connected for operation as a single pole switch. The three poles of the switch of 1Fig. 8 are shown only diagrammatically and are designated 175, 176 and 177. The main stationary contacts 139 and 140 are diagrammatically shown as dots to facilitate a showing of the current equalizers 129.

The main contacts 139 and 140 of the three poles are connected in multiple to the collector bars 14 and 15, respectively. The neutral point 12 is connected to the three poles 175, 176 and 177 through three current equalizers 178 each comprising two inductively coupled windings 179 and a magnetic core 180. The individual cores 1 80 may advantageously be magnetically coupled together, as by constituting separate legs of a three-legged core structure.

While I haveshown what I believe to be the best embodiments of my invention, it will be apparent to those skilled in the art that many changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

l. A switch construction, comprising a plurality of stationary contact members disposed in spaced relationship in a circular arcuate configuration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a contact carrier eccentrically pivoted to said shaft, a plurality of movable contact members carried by said carrier, said contact members being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact members radially toward said stationary contact members, said movable contact members being spaced apart at their outer cnd portions for individual engagement each with a coopcrating one of said stationary contact members, and planetary gear means separate from all of said contact members driven bysaid shaft, said gear means being mechanically connected to said carrier for maintaining said movable contacts positioned for said individual engagement with said stationary contact members.

2. Afswitch construction according to claim l, and in which at least one of said stationary contact members comprises a plurality of separate portions simultaneously engageable by the one of said movable contact members which cooperates therewith, said switch construction further comprising a common connection to said separate portions and current equalizing means included in said common. connection for equalizing load current distribution among said separate portions.

3. A switch construction according to claim 2, wherein said current equalizing means comprises a plurality of inductively coupled windings each having one end thereof L individually connected to one of said separa.e portions,

the other ends of all of said windings being connected together to form a single terminal for said common connection.

4. A switch construction, comprising a plurality of stationary contact members disposed in spaced relationship in a circular arcuate configuration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a contact carrier eccentrically pivoted to said shaft, a plurality of movable contact arms carried by said carrier, said contact arms being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact arms radially toward said stutionary contact members, a plurality of movable contact members each carried by one of said arms at the outer end thereof, said movable contact members being spaced apart for individual engagement each with a cooperating one of said stationary contact members, and planetary gear means driven by said shaft and connected to said carrier for maintaining said movable contacts positioned for said individual engagement with said stationary contact members.

5. A switch construction, comprising a plurality of stationary contact members disposed in a circular arcuate configuration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a

contact carrier eccentrically pivoted to said shaft, a plurality of movable Contact members carried by said carrier, said contact members being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact Imembers radially toward said stationary contact members, said movable contact members being spaced apart at their outer end portions for individual engagement each with a cooperating one of said stationary contact members, internally toothed ring gear means concentric with said shaft and separate from said stationary sedere contact members, and externally toothed gear means mounted on said contact carrier concentricallyV with respect to said pivotal axis thereof, said externally and internally toothed gear means being in continuous meshing engagement with each other for maintaining said movable contacts positioned for said individual engagement with said stationary contact members.

6. A switch construction according to claim 5, in which the radius of curvature of said arcuate configuration differs appreciably from the pitch radius of said ring gear means for producing a wiping action accompanying engagement and disengagement between said cooperating contact members.

7. A switch construction according to claim 5, in which the radius of curvature of said arcuate configuration is substantially equal to the pitch radius of 'said ring gear means for minimizing wiping action accompanying en gagement and disengagement between. said cooperating contact members and thereby reducing contact Wear.

8. A switch construction according to claim 5, and in which at least one of said stationary contact members comprises a plurality of separate portions simultaneously engageable by the one of said movable contact members which cooperates therewith, said switch construction further comprising a common connection to said separate portions and current equalizing means included in said common connection for equalizing load current distribution among said separate portions.

9. A switch construction according to claim 8, wherein said current equalizing means comprises a plurality of inductively coupledwindings each having one end thereof individually connected to one of said separate portions, the other ends of all of said windings being connected together to form a single terminal vfor said common connection.

l0. A switch construction, comprising a plurality of stationary contact members disposed in a circular arcuate configuration, a revoluble operating shaft having its axis of rotation concentric with said arcuate conguration, a Contact carrier eccentrically pivoted to said shaft, a plurality of movable contact arms carried by said carrier, said contact arms being radially movable with respect to the pivotal axis of said carrier, guide means on said carrier for individually guiding said arms during said radial movement, resilient means urging said contact arms radially toward said stationary contact members, a plurality of movable contact members each carried by one of said arms at the outer end portion thereof, said mo able contact members being spaced apart for individual engagement each with a cooperating one of said sta tionary contact members, internally toothed ring gear means disposed concentrically with respect to said rotational axis of said shaft, and externally toothed gear means meshing with said ring gear means, said externally toothed gear means being connected to said carrier con centrically with respect to the pivotal axis thereof for continuously maintaining at least one of said movable contacts positioned for said individual engagement with said stationary Contact members.

ll. A switch construction according to claim l0, in which the inner end portions of all of said arms are pivotally interconnected with each other.

l2. A switch construction according to claim 10, in which the inner end portions of all of said arms are offset with respect to each other and are pivotally interconnected with each other by a common pivot rod which extends through said offset end portions parallel to said rotational axis of said operating shaft, and wherein said resilient means comprises spring means acting on said common pivot rod.

13. A switch construction according to claim l0, in which said pivot rod is substantially in alignment with the pivotal axis of said carrier and is displaceable radically with respect to said pivotal axis from such alignment during rotation of said operating shaft, said radial displacement being of a reciprccatory character.

14. A switch construction according to claim 10, in which said arms are divided into a plurality of groups, the inner end portions of all of the arms of each group being pivotally interconnected with each other.

l5. A switch construction according to claim l0, in which said arms are divided into a plurality of groups, the members of each group being angularly spaced apart from each other with the members of another group interposed therebetween, all of the inner end portions of the arms of each group being oset with respect to each other and arranged in a row, said inner end portions of each group being pivotally interconnected with each other 'by a common pivot rod which extends through said oiset end portions of said group parallel to said rotational axis of said operating shaft, and wherein said resilient means comprises spring means acting individually on each of said pivot rods.

lo'. A switch construction according to claim l5, in which all of said pivot rods are substantially in alignment with each -other and with the pivotal axis of said carrier, each of said pivot rods being individually displaceable radially with respect to the rotational axis of said carrier from such alignment during rotation of said operating shaft, said radial displacement being of a reciprocatory character.

17. A switch construction according to claim l0, wherein said guide means comprises friction reducing roller means engaging said contact arms.

18. A switch construction, comprising a hollow cylin drical support, a plurality of stationary contact mem* bers disposed in spaced relationship on the interior of said support, a revoluble operating shaft having its axis of rotation concentric with said support, a plurality of contact carriers each individually eccentrically pivoted to said shaft, a plurality of interconnected movable contact arms carried by each of said carriers, said contact arms being simultaneously radially movable with respect to the pivotal axis of their carrier, guide means on said carrier for individually guiding each of said arms during said radial movement, resilient means acting on said arms for urging said contact arms radially toward said stationary contact members, a plurality of movable contact members each carried by one of said arms at the outer end portion thereof, said movable contact members being spaced apart for selective individual engagement with and disengagement from each with a particular cooperating one of said stationary contact members, internally toothed ring gear means disposed concentrically with respect to said rotational axis of said shaft, and externally toothed gear means meshing with said ring gear means, said externally toothed gear means being connected to said carrier concentrically with respect to the pivotal axis thereof for continuously maintaining at least one of said movable contacts positioned for said individual engagement with said particular one of said stationary contact members.

l9. A multi-pole switch construction, comprising a plurality of stationary contact members, disposed in a circular arcuate coniiguration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a plurality of contact carriers individually eccentrically pivoted to said shaft, a plurality of movable contact members carried by each of said carriers, said contact members of each carrier being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact members radially toward said stationary contact members, said movable contact mernbers being spaced apart at their outer end portions for individual engagement each with a cooperating one or" said stationary contact members, and planetary gear means driven by saidr shaft and connected to all of said carriers for continuously maintaining said movable contacts of each carrier positioned for said individual engagement with said stationary contact members.

20. A multi-pole switch construction, comprising a plurality of stationary contact members disposed in a circular arcuate conguration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a plurality of contact carriers individually eccentrically pivoted to said shaft, a plurality of movable contact members carried by each of said carriers, said contact members being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact members radially toward said stationary contact members, said movable contact members being spaced apart at their outer end portions f or individual engagement each with a cooperating one of said stationary contact members, internally toothed ring gear means concentric with said shaft, and externally toothed gear means meshing with said ring gear means, said externally toothed gear means being connected with all of said corr tact carriers for continuously maintaining said movable contacts of each carrier positioned for said individual engagement with said stationary contact members.

2l. A multi-pole switch construction, comprising a plurality of stationary contact members disposed in spaced relationship in a circular arcuate configuration, a revoluble operating shaft having its axis of rotation concentric with said arcuate configuration, a plurality of contact carriers individually eccentrically pivoted to said shaft, a plurality of movable contact members carried by each of said carriers, said contact members of each carrier being radially movable with respect to the pivotal axis of said carrier, resilient means urging said contact members radially toward said stationary contact members, said movable contact members being spaced apart at their outer end portions for individual engagement each with a cooperating one of said stationary contact members, internally toothed ring gear means concentric with the rotational axis of said shaft, and a plurality externally toothed sector gear members all simultaneously meshing with said ring gear means, the teeth of each of said sector gear members being concentric with the pivotal axis of one of said carriers, each sector gear member being connected to one of said carriers for continuously maintaining said movable contacts of said carrier positioned for said individual engagement with said stationary contact members.

22. A switch construction according to claim 2l, and in which at least one of said stationary contact members associated with each of the poles of said switch Ycomprises a plurality of separate portions simultaneously engeable by the one of said movable kContact members which cooperates therewith, said switch construction further comprising a common connection to said separate portions and current equalizing means included in said common connection for equalizing load current distribution among said separate portions.

23. A switch construction according to claim 22, wherein said current equalizing means comprises a plurality of inductively coupled windings each having one end thereof individually connected to one of said separate portions, the other ends of all of said windings being connected together to form a single terminal for *i said common connection.

24. A switch construction according to claim 2l, in which the radius of curvature of said arcuate configuration differs appreciably from the pitch radius of said ring gear means for producing a wiping action accompanying engagement and disengagement between said cooperating contact members.

25. A switch construction according to claim 2l, in which the radius of curvature of said arcuate configuration is substantially equal to the pitch radius of said ring gear means for minimizing wiping action accompanying engagement and disengagement between said cooperating contact members and thereby reducing contact wear.

26. A multi-pole switch construction, comprising a ing its axis of rotation concentric with said circular configuration, a plurality of contact carriers eccentrically pivoted to said shaft, each carrier being associated with one po-le of said switch, a plurality of movable contact arms carried by each carrier, said contact arms being radially movable with respect to the pivotal axis of said carrier, guide means on each carrier for individually guiding said arms during said radial movement, resilient means urging said contact arms radially toward said stationary contact members, a plurality of movable contact members each carried by one of said arms at the outer end portion thereof, said movable contact members being spaced apart for individual engagement each with a cooperating one of said stationary contact members, internally toothed ring gear means disposed concentrically with respect to said rotational axis ofv said shaft, and a plurality of externally toothed sector gear means all meshing with said ring gear means, said each of said sector gear means being connected to one of said carriers concentrically with respect to the pivotal axis thereof for continuously maintaining at least one of said movable contacts of said carrier positioned for said individual engagement with one of said stationary contact members.

27. A switch construction according to claim 26, in which the inner end portions of all of said arms of each carrier are pivotally interconnected with each other.

28. A switch construction according to claim 26, in which the inner end portions of all of said arms of each carrier are offset with respect to each other and are pivotally interconnected with each other by a common pivot rod which extends through said offset end portions parallel to said rotational axis of said operating shaft, and wherein said resilient means comprises spring means acting on said common pivot rod.

29. A switch construction according to claim 26, in which said arms of each carrier are divided into a plurality of groups, the inner end portions of all of the arms of each group being pivotally interconnected with each other.

30. A switch construction according to claim 26, in which said arms of each carrier are divided into a plurality of groups, the members of each group being angularly spaced apart from each other with the members of another group interposed therebetween, all of the inner end portions of the arms of each group being offset with respect. to each other and arranged in a row, said inner end portions of each group being pivotally interconnected with each other by a common pivot rod which extends through said otset end portions of said group parallel to said rotational axis of said operating shaft, and wherein said resilient means comprises spring means acting individually on each of said pivot rods.

3l. A-switch construction according to claim 30, in which all of said pivot rods are substantially in alignment with each other and with the pivotal axis of said carrier, each of said pivot rods being individually displaceable radially with respect to the rotational axis of said carrier from such alignment during rotation of said operating shaft, said radial displacement being of a reciprocatory character.

32. A switch construction according to claim 26, wherein said guide means comprises friction reducing roller means engaging said contact arms.

References Cited in the tile of this patent UNITED STATES PATENTS 1,993,720 Nye Mar. 5, 1935 2,680,163 Besserer June l, 1954 2,680,790 Jansen lune 8, 1954

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