US1882687A - Electric switch - Google Patents

Description

Oct. 18, 1932. C, D, NNSWORTH 1,882,687

ELECTRI C SWITCH Filled May 5l,` 1930 2 Sheets-Sheet l Oct. 18, 1932.

c. Dv AlNswoRTH 1,882,687

ELECTRIC SWITCH Filed May 51, 1930 2 SheetS-Shee'r. 2

Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE'.

CHESTER D. AINSWORTH, OF WOLLASTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELEC- TRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A

CORPORATTON OF MASSACHCUSETTS ELECTRIC SWITCH Application filed May 31, 1930. Serial No. 458,874.

This invention relates to electric switches for controlling high tension circuits and particularly those which employ, in addition to the main Acurrent carrying contact members, auxiliary arcing tips. One common form of switch includes a pair of vertical conducting studs which terminate at their lower ends in Xedcontact members, and a vertically reciprocable bridging member which is moved into and out of engagement with the fixed contact members to close and open the circuit through the switch. As thus constructed, the current path through the switch is substantially of U-shape and the magnetic forces set up by the current flowing in the U-shaped path tend to distort the current carrying parts of the switch, and l particularly the resiliently mounted arcing tips, and break the circuit.

It is an object of this invention to provide an improved construction for counteracting the magnetic forces tending to separate the arcing tips upon the passage of heavy current through the switch circuit.

A further object is to provide a current conducting` loop in the vicinity of and including a movably mounted arcing contact member which must be traversed by the 'current passing through the switch and inwhich the magnetic forces set up react on the movable arcing contact member to urge it in a switch closing direction, thus to oppose the magnetic reactions on the contact member of the general U-shaped current path through the switch. v

A still further object is to provide a movable switch member having reactive arcing contact members which is designed to carry heavy currents at highvoltage. The principle embodied in the present switch is described and claimed in my copending application Serial No. 242,666, filed December 27, l 1927, which has eventuated into Patent No. 1,762,- 604, and it is an obje-ct of the present invention to improve upon fthe .structure of the switch of said application, so that it can carry and interrupt heavier currents.

A yet further object of the invention is geni erallyto improve the construction and operation of electric switches and contact structures therefor.

Fig. 1 is a side elevation of the contact structure of an electric switch embodying the invention.

y Fig'.'2 is a sectional view of the movable bridging member taken along line 2-,2 of Fig. 1.

Fig. 3 is an end elevation of the movable switch member of Fig. 1. v

Fig. 4 is a sectional view along line 4-4 of Fig. 1.

Fig. 5 is a transverse sectional elevation through the movable switch member.

Fig. 6 is a perspective view illustrating the current conducting loop in the vicinity of a movable' arcing Contact member.

Fig. 7 is a perspective view of a bracket for supporting the arcinrf tip arm.

Fig. 8 is a line diagram showing the current path through the movable bridging member.

Fig. 9 is a perspective detail of the support for the arcing members.

The electric switch herein shown is of the down break oil immersed type, only that part of the switch being shown which is necessary Jfor an understanding of the invention. The switch includes a pair of insulated vertical spaced current conducting studs 10 and 12 which carry at their lower ends contact attaching blocks 14 which are screw-threaded thereon and which are fixed against rotation on the studs by means of suitable clamping nuts 16. Said blocks carry at their lower ends the stationary main and auxiliary contact members. Said stationary main contact members comprise the laminated brush members 17 of the inverted, or non-reactive, type having the horizontal shank portions 18 and the downwardly and inwardly directed toe portions 20 which terminate in substantially horizontal contact faces 22. The shank portions 18 of said brush members are secured detachably to the lower face of said blocks 14 by means of bolts 24 which pass through said brush members and are screw-threaded into said blocks. Said stationary arcing members comprise cylindrical arcing tips 26 contact v bolts 50 which extend which are secured by means of bolts 28 between the biturcated ends of depending brackets 30 which are secured to the vertical seats 32 of blocks 14.

A vertically reciprocable switch member is provided comprising a bridging member having main and auxiliary contact members which are adapted to cooperate with the stationary main and auxiliary contact members to close Vand open the circuit through Vthe switch. Said movable switch member includes a. vertical insulating switch, or lifting rod, 34 at the lower end of which is loosely supported a horizontal bridging member comprising essentially a horizontal plate'36 having the flat upper contact tace 38 which is adapted to cooperate with the horizontal contact faces 22 of the stationary main contact members. Said bridging member is provided with a central circular passage 40 through which the switch rod 34 extends freely. Y

As shown most clearly in Fig. 5 the lower end of said switch rod 34 is formed with an annular shoulder 42 which defines the upper limit of a conical or flared end portion 44 which is larger at the bottom and smaller at the top Ywhere it forms said shoulders. A pair ot clamping members 46 and 48 having complemental tapered recesses therein are clamped about the attaching portion 44 on opposite sides of Vsaid rod by clamping Y through suitable outstanding ears 52 of said clamping members at either :side of the switch rod., Said clamping members provide at their upper ends the horizontal top surface 54 against f which the shoulder 42 of the switch rod is adapted to abut. One of said clamping members, asthe right hand member 48 in Fig. l, is provided with a pair of oppositely extended upstanding arms 56, terminating in parallel llat Vears 57 which lie normal toa transverse vertical plane including vsaid switch rod. Each ear 57 is closely received between spaced depending flanges, or webs, 58 and 60 on the bottom face of the bridging member 36 of which a pair is provided at eachside ot the switch rod. Said arms 5,6 andV theilanges 58 and 60 of the bridging member are provided with aligned horizontal passages 'which are extended transversely therethrough in the plane of said switch rod 34 inwhich pivot pins 62 are received, one on eachside of saidswitch rod, whereby to support the bridging member 36 for pivotal movement on the arms 56 of said clamping member. The passages through the, outer flanges 58 of the bridging member are counterbored -to provide recesses 64'in which the heads 65 of the pins are received. A retaining plate 66 is secured over the outermost end of each of said pins 62 in covering relation with the head 65 thereof and is held in placeby means of screws 68 which are threaded into the flanges 58 of the bridging member, whereby to prevent displacement of the pins. The passage 40 through the bridging member 36 is only slightly larger than the diameter of rod 34 so that the pivotal movement of thel bridging member about the supporting pins 62 is limited to the small movement necessary to insure alignment with-the cooperating main contact members when the switch is closed.

The movable arcing-contact members are supported beneath the bridging member 36 on opposite sides of and at the lower end of the movable switch rod. To this end a supporting member comprising' a channel member 69 having horizontal lconnecting webs 70 and the spaced parallel upstanding side walls 72 is located beneath said bridging member and has itsside walls disposed between the innermost parallel webs 60 of said bridging member. The web has a central passage 73 for the switch rod 34 and the side walls have centrally located depending ears 74 provided with passages 76 through which the innermost ends of pins 62 extend. The channel member is prevented from undue pivotal movement on the pins 62 by reason of the engagement ofthe horizontal ends 78 of said ears with the top face 54 presented by the clamping members 46 and 48. Said channel member is of goed conducting material and constitutes a part of the auxiliary current path through the switch. e

The arcing members and the conducting and supporting structure thereof is du alicated at each side. of vthe vertical switch rod. As shown most clearly in Figs. 6 and 7 a movable arcing member includes a horizontal cylinder 80 which is secured by means of bolts 86 between the outer biturcated ends 82 ot the supporting arm 84. The arm 84 is also bifurcated at its inner end to provide the spaced ears or arms Y88 which receive therebetween the upstanding boss 900i a supporting bracket 92. A pin 94 extends through the boss 90 and the ears 88 whereby to support the arm 84 for pivotal movement in a vertical direction about its innermost end. The bracket 92 is parallel with and is supported rigidly from and beneath the end of the channel member 69. lTo this end a U- shaped frame 96 is secured to the bottom tace Vot the channel member 69 by bolts 98 and is provided with spaced depending side walls 100 which receive the bracket 92 therebetween but which are spaced apart therefrom. Said bracket 92 is provided with a cylindrical passage 102 therethrough in which an insulating bushing 104 is closely received and which extends between the depending arms 100 of the frame 96 and is supported by a pin 106 which is .fixed in said frame. It will thus be evident that the bracket 92 is supported at its inner endby and is insulated from the trame 96. Said bracket 92 is supported at its outer end and is electrically connected with the channel membei1 by means of a rigid conducting` bar or strap108 which includes the vertical depending leg 110vwhich is closely received in a vertical groove `112 at the end of said bracket 92. Suitable bolts 114 are screw-threaded into said bracket 92 and clamp the lower ends of said bar 108 fixedly thereto. Said bar 108 is provided with an upper relexed horizontal poi-tion 116, as shown most clearly in Fig. 4, which lies within the channel member 69 and is secured lixedly to the web or bottom wall 70 thereof by bolts 98. As shown most clearly in Fig. 2 the. ends 82 of the movable arcing arm 84 are spaced apart a sui'licient distance to permit the bar 108 to pass therebetween free from contact therewith.` Good electrical connection is establishedV between the arcing arni84and the bracket 92 by means of a flexible conducting braid 118 which is secured by a screw 120 to the arm 84 at one end and by a screw 122 to the bracket 92 at its other end thus to provide a shunt about the pivotal support for the arcing arm 84. A thin sheet of insulating material 124 is provided between the arms oi fra Ae 96 above the braid 118 to prevent possible contact et thebraid withV said frame, and Va similar sheet of insulating material 128 is located between the clamping member 48 and thev bracket 92. Said insulating sheets are retlexed about the end of lthe bar 108and are securedin position byone of the clamping bolts 98. 1 r

The movable arcing member is adapted normally to be urged upwardly into pressure engagment with the cooperating stationary arcing member 26.` To this end a spring 128 is rctlexed about the pivot pin 94 and has substanti ally parallel upper an d lower arms which Ybear against he bracket 92 and the arm 84 in opposite directions, thus constantly to urge them apart. A U-shaped insulating member 130 is secured in place on the central portion of said arm 84 and has la lower leg 182 thereof interposed between the arm and the spring 128 so that the spring will not be traversd by current. The upper arm 134 of said insulating member constitutes an insulating stop which engages the end of the channel vmember 69 to limit the upward movement `of the arm 84 and to prevent short-circuiting of the conducting loop.

The construction each arcing member is or can be as above described.

As shown most clearly in 8 the construction above described provides a current conducting loop which is located in the vicinity of and includes each of the movable arcing arms 84. Due to the location of the movable aiming arm 84 between the parallel conductors 69 and 92 a strong reactive torce is exerted on said arm in an upward direction.

It will loe-noted that the current flowing in arm 84 and bracket 92 is in opposite directions whereby to exert a repulsive ellect on the movable arm 84 in a direction to urge the movable arcing member 80 upwardly against the cooperating contact 26; while the current flowing in the channel 69 and the bar 108 being in the same direction as the current in arm 84 exerts an attractive torce which also urges the arcing members into engagement. By reason of the tact that thc magnetic loop is localized in the vicinity ci each arcing member, the repulsive effect on the arcing members, due to the general U-shaped path through the switch is overcome, and the cooperating arcing contact members consequently remain in good pressure engagement during the initial opening oic the switch while the main contacts are separating. The magnetic field produced by the aforesaid conducting parts also reacts on the arcs drawn between the separated arcing members to blow out the arcs.

Various changes in the construction and arrangement of the parts can be made without departing from the scope of the invention.

l claim:

1. A movable switch member for an electric switch including` a vertical lifting rod, a transverse bridging member pivot-ally supported at the lower end of said rod, a transverse conducting member carried by said rod beneath said bridging member, a conducting bar lixed to and extended beyond the end ot said conducting member having an angularly related depending leg, a bracket fix-ed at one end to said leg and having its tree end disposed beneath said conducting member, insulated supporting means rigidly connecting the free end of said bracket with said conducting member, an arm overlying said bracket and having a pivotal support on the free end ot said bracket, said arm arranged to extend outwardly beyond the vertical leg of said bar, and an arcing member carried by the extended end of said arm.

2. A movable switch member for an electric switch including a vertical lifting rod, a transverse bridging member pivotally supported at the lower end of saidrod, a transverse conducting member carried by said. rod beneath said bridging member, a conductiiig` bar iixed to and extended beyond the end ot' said conducting member having a depending leg7 a frame depending from said conoucting member, a bracket fixed at one end to said cepending leg and having its other end supported by said frame, a generally horizontal arm overlying said bracket having a pivotal connection therewith adjacent said trame, said arm being extended outwardly beyond. the vertical leg of said bar, and an arcing member carried by the extended end of said arm.

8. A movable switch member for an electric switch including a vertical lifting rod, a transverse bridging member pivotally supported at the lower end of saidrod, a transverse conducting member carried by said rod beneath said bridging member, a conducting bar fixed to and extended beyond one end of said' conducting member havingdepending leg, a horizontal bracket lined at one end to the lower end of said leg and having its free end disposed beneath said conducting member, insulated supportino' means for the free end of said bracket including a frame lined to and depending from said conducting member, a generally horizontal arm overlying said bracket and having a pivotal connection therewith adjacent said frame, said arm having an end portion which extends outwardly beyond and is free from contact with said vertical leg, and an arcing member carried by the extended end of said arm.

4;. A movable switch member for an electric switch including vertical lifting rod,

clamping member disposed at the lower end of said rod, a transverse bridging member pivotally supported on said clamping member, a transverse conducting support carried by said clamping member beneath said bridging member, a frame depending beneath said support, a horizontal bracket supporter at one endby sai l frame and insulated therefrom, a horizontal aim having ay pivotal connection aiL one end on said bracket said frame, and having an arcing member at its free end, rigid electrically conducting means connecting the other end of said bracket with said conduct-ing support, and means constantly biasing said arm for movement about its pivot in anV upward di ection.

5. A movable switch member for electric switch including a vertical lifting rod, a clamping member disposed at'the lower ent of said rod, a horizontal bridging member pivotally supported cn said clamping member, a horizontal conducting support located beneath said bridging member and pivotally d by said clamping member concenth said bric ng member, a frame sai(1 condi support and dependir r d conducting bar having io 'ontal `leg which 1s se ured to sain. conducting member and entends beyond the end thereof and a vertical leg which depe thercbelow, conducting bracket haw an electrical connection v i said vertical leg at one endand an insulated connection with 'd frm e at its other end, movable arcing arm ha a pivotal connection on one end of said bracket adjacent said fV ine and having an arcing member at its free end, saiLL arm being disposed v,nd ger y parallel said ccndueting support ai fl brach t. Y

A ovable switch meinbe' fer an electric switclincluding a vertical insulating rod, a horizontal bridging' member hav a pivotal support at the lower end of sai rod, a conducting support located beneath said bridging member having a concentric pivotal support on said rod, a depending frame carried by said supporting member, a conducting bar also carried by said supporting member having a depending leg which is laterall spaced from said frame, a horizontal brac ret having an electrical connection at one end with said leg and having an insulating connection at its other endwith said frame, said support and said bar and bracket lying in a common vertical plane, and an arm disposed between said support and bracket and in the same vertical plane therewith having a pivotal support at one end on said bracket in the vicinity of said frame andl having a bifurcated end portion which is extended outwardly beyond said depending leg, the bifurcations of said arm being spaced apart from said leg, and an arcing member cai ied by the free end of said arm between the bifurcations thereof.

A movable switch member for an electric switch including a vertical lifting rod, a clamping member carriedby the lower end of said rod having spaced upstanding arms, a transverse bridging member pivotally supported on said arms having a central passage through which said rod extends, a transverse conducting support supported by said clamping member beneath said bridging member having a central passage through which said rod extends, horizontally extended conducting bars carried by the ends of said support having depending legs, inwardly-directed horizontal brackets carried by the lower ends of said legs having their free ends located adjacent said vertical rod, insulating supports for the free ends of said brackets, generally horizontal arms overlying and having pivotal connection with said brackets adjacent. the free ends thereof, said arms arranged to extend outwardly beyond and free from electrical connection with said legs, and arcing members carried by the extended ends of said arms.

8. A movable switch member for an electric switch including a vertical lifting rod, a transverse bridging member having a central passage therethrough for said rod, a transverse conducting support located beneath said bridging member having a central passage for said rod, a clamping member carried by the lower end of said rod, means pivotally connecting said bridging member and said conducting support to said clamping member rigid 'conducting bars fixed to said support at the ends thereof having depending legs, horizontal brackets carried by said legs and extended inwardly toward said rod, frames carried by said support adjacent the ends thereof having spaced depending arms, insulating bushings fixed between said arms and extended through the free ends of said said brackets and extended outwardly therebeyond, said arms having pivotal connections with said brackets at their inner ends and having bifurcated outery end portions which are disposed on opposite sides of and are free from contact with said legs, and arcing members carried by the bifurcated ends of said arms.

9. A movable switch member for an electric switch comprising a lifting rod, a conducting supporting member secured to said rod, a rigid conducting bar having a horizontal portion one end of which is connected with one end of said supporting member and having a vertical depending portion, a bracket having a. horizontal leg the end of which is fixed to the end of said depending portion, said bracket having an upstanding leg at the end of said horizontal leg remote from said depending portion under said horizontal portion, a horizontal arm located between said horizontal leg and said horizontal portion having one end connected with said upstanding leg for vertical movement and having its other end located beyond said vert-ical portion, a contact member carried by said other end, and a spring which urges said arm in an upward direction.

l0. A movable switch member for an electric switch comprising a lifting rod, a conducting supporting member secured to said rod, a rigid conducting bar having a horizontal portion one end of which is connected with one end of said supporting member and having a vertical depending portion, a bracket having a horizontal leg the end of which is fixed to the end of said depending portion, said bracket having an upstanding leg at the end of said horizontal leg remote from said depending portion under said horizontal portion, a horizontal arm located between said horizontal leg and said horizontal portion having one end connected with said upstanding leg for vertical movement and having its other end located beyond said vertical portion, a contact member carried by said other end, a spring which urges said arm in an upward direction, and insulated means rigidly connecting said bracket and said supporting member.

l1. In an electric switch, a movable switch member comprising a lifting rod, cooperating clamping members fixed to the lower end of said rod, one of said members having opposed spaced ears which lie on opposite sides of said rod, a supporting member which straddles said rod and has supporting connections with said ears, rigid horizontal conductors fixed to the opposite ends of said supporting member having depending end sections, brackets lying close to said rod under said supporting member having horizontal legs which are fixed to the ends of said depending sections and having vertical legs which upstand under said supporting member, arms which are located between said horizontal legs and said supporting member and have theirl inner ends pivoted to said vertical legs and their outer ends extended outwardly beyond said depending sections, arcing members carried by said outed ends and springs which bear on said arms and urge them upwardly about their pivotal connections.

12. An electric switch having stationary switch members and a cooperating movable switch member comprising a vertical'lifting rod,` a pair of cooperating clamping members clamped on the lower end of said rod, one of said clamping members having opposed outstanding arms, a horizontal bridging membei' having an opening therein through which said lifting rod is freely extended, depending webs on said plate which confront said arms, and pivot pins passed through said webs and arms whereby pivotally to connect said bridging member and lifting rod.

13. An electric switch having stationary switch members and a cooperating movable switch member comprising a vertical lifting rod, a pair of cooperating clamping members clamped on the lower end of said rod, one of said clamping members having opposed outstanding arms, a horizontal bridging plate having an opening therein through which said lifting rod is freely extended, depending webs on said plate which confront opposite faces of each of said arms, and pivot pins passed through said webs and said arms whereby pivotally to connect said bridging member and lifting rod.

14. An electric switch having stationary switch members and a cooperating movable switch member comprising a vertical lifting rod, a horizontal bridging plate having an aperture therein through which said rod is extended freely, y and pivotal supporting means for said plate comprising a supporting member having ears which are located on opposite sides of said rod under said plate, means securing said supporting member on the lower end of said rod, said plate having depending webs opposed to said ears, and pivot pins extended between said webs and ears.

15. An electric switch having stationary switch members and a cooperating movable switch member comprising a vertical lifting rod, a horizontal bridging plate having an aperture therein through which said rod is extended freely, and pivotal supportingmeans for said plate comprising a supporting member having ears which are located on opposite sides of said rod under said plate, means securing said supporting member on the lower end of said rod, said plate having depending webs opposed to said ears, pivot pins extended between said webs and ears, and plates connected by said webs and overlying the outer ends of said pins and constitu'ting means which placement of said pins.

16. An electric switch having stationary switch members and a cooperating movable switch member comprising a vertical lifting rod, a horizontal bridging plate having an aperture therein through which said rod is extended freely, and pivotal supporting means for said plate comprising a supporting member having ears which are located on opposite sides of said rod under said plate, means securing said supporting memberv on the lower end of said rod, said plate having depending webs opposed to said ears,

pivot pins extended between said webs and ears, plates carried by said webs and over- 'lying the outer ends of said pins and constituting means which prevents axial displacement of said pins in one direction, the inner ends of 'said pins confronting and beig located close to said lifting rod.

17. An electric switch having stationary contact members, a movable switch member including a bridging member, contact supporting' arms, brackets which support said arms, supporting means for said brackets by which theyV are insulated from each other and from said bridging member, and means electrically connecting said brackets.

18. An electric switch having stationary ycontact members', a movable switch member including a bridging member, oppositely directed contact supporting arms having contact members at their outer ends, brackets which have pivotal connections with the inner ends of said arms and have extensions which underlie said arms, supporting means for said brackets which insulates them from each other and from said bridging member, and conducting means which electrically connects the extensions of said brackets.

19. An electric switch having stationary contact members, a movable switch member including a bridging member, oppositely directed Contact supporting arms having contact members at their outer ends, brackets which have pivotal connections with the inner ends of said arms and have extensions which underlie said arms, supporting means for said brackets which insulates them from each other and from said bridging member, and conducting means which electrically connects the extensions of said brackets and which overlies said arms.

In testimony whereof, I have signed my name to this specification.

CHESTER D. AINSWORTH.

prevents axial dis;

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