US2644878A - Switch construction - Google Patents

Description

July 7, 1953 s.- LINDELuswITcH CONSTRUCTION original Filed July so, 1948 3 sheets-smet 1v IN VEN TOR. gardflmdel, BY

my C@ s. l. LINDELL SWITCH CONSTRUCTION July 7,- `1953 3 Sheets-Shed.' 2

original Fgllea July 30.-. 19'48- v INVENTOR.- fgfd/Iazdd, BY

s. l.- LINDELL July 7, 1953 original Filed July'so, 194e s sheets-shut 's 1 um. @Q

Patented July 7, 1953 Sigurd' LLindell, Chicago, Ill.,I assignor to S &. C, Electric Company, Chicago, Ill., a. corporation of Delaware Original application July 30, 1948, Serial No..

1950,'. Serial No;.164,702

7 Claims. (Cl. ZIN- 170) This invention relates,L generally, to switches for opening high voltage alternatingjcurrent circuits and it has particular relation. to such switches that are capable, of interrupting load current, magnetizing current, .charging current, etc. This application isa division of application Serial No. 41,597, filed July 30; 1948'. An improve.- mentfon the construction disclosed. `herein s-vdisclosed in copending application-Serial No. l59,- 025, filed April 2.9, 1950, and assigned to the. assignee. of this application, now Patent No. 2,5671-,- 606 issued September 11, 1951.

Among the objects orthis invention are: To accelerate a switch blade with a snap: action into and out of switch closed position by employing spring biased contact fingers rockable overeenter to and from a self-locking position; to mount the contact iingers on opposite.- sides of the plane of movement of the switch blade about parallel axes in a plane at right angles to the. plane of movement of the switchfblade; to bias thev contact lingers towardv each other; to limit the swinging movement of the Contact lingers` in either direction; to employ a pair of generally U-shapedrspring clips for mounting the Contact lingers; to nest the springv clips sothat. one clip pivotally supports the ycontact fingers and the other clip engages them to conduct the principal portion of the lcurrentthereto; and to employ generally pear shaped members for the contact lingers.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

For a more .complete understanding of the `na ture and scope of this invention, refe-rence can behad to the following detailed description, taken together with the accompanying drawings, in which:

Figure 1 is a View in front elevation of a gang operated switch construction in which the present invention is embodied and illustrating how it can be employed with high voltage fuses, the entire assembly being arranged for mounting in a vertical plane.; l

Figure 2 is a view, in sideelevation, of the switch construction shown in Figure l with the fuses associated therewith; p

VFigure 3 isa detailed sectional viewr, at an enlarged scale, taken along the line 3 3 of Figure l, showing the outer end of the insulator which carries the stationary switch contacts andY load interrupter, the switch-,f'blade being shown in closed position;

Figure fi-is a View, partly in Divided and this'. application May 2.7.',

Figure 5 is ayiew,similar to Figure 3, the load interrupter being omitted, showing how the switch blade approaches the stationary switch contacts and their position before engagement 'by the switch blade;

Figure 6v is a view, similar to Figure 5,V showing the switch blade. in engagement with the stationary switch contacts just prior to its nal movement to the switch closed position;

Figure 7 is a detail sectional view, taken along the line. 'I-'I of Figurer 6, showing the load interrupter andthe switchl blade in the switch closed position; and

Figure 8 isa longitudinal sectional view of the lo'ad interrupter.

Referring, now particularly to Figure 1 of the drawings, it will be observed that the reference character I Il designates, generally a three phase gang. operated switch construction. While this polyphase. switch arrangement has been illustrated, it. will be understood that the present invention can be employed ina single phase switch.

The gang operated switch construction Ill includes switches that are shown, generally, at Il which are of identical construction. Accordingly,v av description of one will suice for all. The. switches.. I`I` may be connected in series circuit relation withfuses which are shown, generally at I2. The fuses I2 are provided to take care of short circuit protection, the switches II being arranged, as will appear in detail hereinafter, to open the circuit only when a normal load current isiiowing therethrough. Itis not intendedA that switches II will open. the circuit under short circuit conditions.

As illustrated in Figure 2, each of the switches Il and fuses I2Y may be mounted in series on a channel; iron support I3. In. Figures l and 2 of the drawings, the channel iron support I3 is shown as being located in a vertical position. In accordance with this invention the channel iron support I3'can be located either in the vertical position, as shown, or in a horizontal position with the switch I I either above or below it. The

plan and partly in fuses I2, as shown in the. drawings, are intended only for mounting in the. vertical position shown. However,v there are many instanceswhere it is desirable to mount the. -switches II on a pole top wherethe. switch I Il will beV uppermost or in other installations where` it will be under-hung. As will appear hereinafter the present construction can be employed without change for any of these applications.

The. channel iron support` I3 carries three stasection, of the principal portion of the yblade tip; u tionary insulators I4 the length of which is determined by the voltage of the circuit in which the switches I! are connected. At their outer ends the insulators I4 are provided with contact and terminal mounting brackets that are indicated, generally, at I5 and i6. The mounting brackets I5 are provided with intermediate sections I1 and end sections i8 which provide terminal pads. It will be understood that the upper terminal pad I8 may be connected to one terminal of the circuit in which the switch II is to be interposed. The other end section I8 is arranged to carry a fuse clip I9 in which is positioned the upper end of the fuse I2. The mounting bracket I6 has a section 2t for attachment to the lowermost insulator I4 and also a terminal pad section 2| to which the other` circuit terminal can be connected as will be understood readily. The fuses I2 may be any of the well known types now available. They are illustrated in Figures 1 and 2 of the drawings merely to show a typical installation of the switch I I respecting which the present invention is particularly directed.

As shown in Figure 3 of the drawings, each of the contact and terminal mounting brackets I5 may be secured by bolts 24 extending through the intermediate section I1 to secure the same to the upper end of the associated insulator I4. Each bracket I5 has an upstanding section 25 which is offset somewhat from the longitudinal axis of the insulator I4 and it has a flange 26, Figure 1, extending at right angles from the rear side to provide additional strength and rigidity.

Intermediate the ends of the upstanding section 25 is an angle clip 21 which is secured thereto by bolts 23. The angle clip 21 has stationary contacts 29 secured thereto by bolts 3D. The details of construction of the set of stationary contacts 25 will be described hereinafter. For the present it is pointed out that `the stationary contacts 29 extend generally parallel to the upstanding section 25, and,`in the particular construction shown, they extend horizontally.

At the outer end of the upstanding section 25 is another' angle clip 3| which may be secured thereto by suitable bolts. One leg of the angle clip 3l extends at right angles to the upstanding section 25 and carries a load interrupter 33 which is secured theretoby bolts 34. The details of construction of the load interrupter 33 are generally the same as those shown in Lindell et al. Patent No. 2,351,825 issued June 20, 1944. It is pointed out here that the longitudinal axis of the load interrupter 33 is generally parallel to the face of the upstanding section 25 and that it extends horizontally. :Because of this relationship the longitudinal axis of the load interrupter 33 will always extend horizontally regardless of whether the support I3 is positioned vertically, as shown, or occupies a horizontal position with the load interrupter 33 either above or below it as the case may be. rlhis is important from a weather standpoint. Also, it provides a compact arrangement in which sufficient electrical clearances are established and maintained to isolate the main stationary contacts 29 and their associated line terminals I8 from the movable main contacts or switch blade to be described.

intermediate the upper two insulators I4, as shown in Figure 2, there is a rotatable insulator' 35 which carries a switch blade 36 at its outer end. The switch blade 35 in the present construction is tubular and is formed of hard drawn copper. Obviously it may have other shapes and be formed of other material as desired. As will appear hereinafter, the ends of the switch blade 36 are arranged to engage the stationary contacts 29 which are located at its ends and also to cooperate with the load interrupters 33 at its ends for opening the circuit at two places and drawing two arcs which are extinguished thereby.

The insulator 35 is rotatably mounted by a bearing 31 which is carried by the support I3. At the lower end of each of the rotatable insulators 35, as shown in Figure l, there is an operating arm 38. As there shown the operating arms 38 are interconnected by connecting rods 39 so that conjoint movement of the insulators 35 and switch blades 36 carried thereby is effected. An operating rod 40 serves to interconnect the operating ram 38 of the right hand rotatable insulator 35 with one arm of a bell crank 4I which is rockably mounted on the intermediate support channel I3. The other arm of the bell crank 4I is connected by a rod 42 to a spring operator 43 which, in turn, is connected to an operating rod 44 that extends downwardly to a manually operable operating handle (not shown). The spring operator 43 is provided to effect the initial opening movement of the switch blades 33 and the final closing movement thereof with a snap action that is independent of the force exerted by a lineman on the operating handle which is connected to the operating rod 44.

Referring now particularly to Figures 3, 5 and 6 of the drawings, it will be noted that each outer end of the switch blade 36 carries a blade tip that is indicated, generally, at 41. The blade tip 41 may be a brass casting and it may be secured to the end of the switch blade 36 by a bolt 48. Each blade tip 41 has an offset integrally formed contact arm 49 with a wedge shaped blade 5D at its outer end provided with grooves 5I a slight distance from its outer edge for intertting with the smaller ends 52 of pear-shaped contact fingers 53. The pearshaped contact fingers 53 preferably are formed from extruded yellow brass that is silver plated and the smaller ends 52 are arranged to engage inlays of silver at the bottom of the grooves 5I. Flanges 54 are formed integrally with the contact arm 49 for the purpose of picking up the contact fingers 53 when the blade 50 is moved toward the switch closed position in the direction indicated by the arrow 55.

The pear-shaped contact fingers 53 are rockably mounted by hinge pins 56 in the bifurcated hooked ends 51 of an inner U-shaped spring clip 58. Tongues 59 project between the hooked ends 51 to provide stops for limiting the rocking movement of the contact lingers 53 in the switch closed position as illustrated in Figure 3.

Nested with the inner U-shaped spring clip 58 is an outer U-shaped spring clip 60 the outer ends 6I of which bear against the larger ends 62 of the pear-shaped contact fingers 53.

With a View to holding the contact fingers 53 in the open position as shown in Figure 5, the larger ends 62 are provided with flattened surfaces 53, Figure 3, against which the outer ends 3| of the spring clip 60 rest for holding the contact fingers 53 in the position shown in Figure 5. In addition extensions 64 are formed integrally with the contact fingers 53 and, as shown in Figure 5, they are arranged to engage the outer surfaces of the inner spring clip 58 at the base of the tongues 59 to insure that the contact iingers 53 do not swing past their positions as shown in Figure 5.

It will be understood that each of the stationary contacts 29, referred to hereinbefore, is formed by the nested spring clips 58 and 60 and the pear-shaped contact fingersy 53. Thespring clips 58 and 60. are formed of good electrical conducting material such as. beryllium. copper which, in addition, has good resilient characteristics. Preferably they are bright silver plated. The construction of the stationary contact/29 is such that, when the contact armA 49 is swung to the switch closed position, the outer endsV 6i of the outer spring clip. 582 are required to.V move. further than the outer endsy of the inner spring clip 58. Accordingly, it is desirable that the. resiliency of the outer spring clip 60 be greater than that of the inner springr clip 58'. Accordingly, while the spring clips 58 and 60 are the same width, the thickness of the outer spring clip 60. is substantially less than that of the inner spring clipv 58. For example, the. inner spring clip 58'` may be formed of a strip of berylliumv copper having an initial length of 11% inches, awidth of 1% inches and a thickness of 0.128 inch, while the. outer spring clip 68 may be formed from a strip of beryllium copper having an initial length of inches, a width of 1% inches and a thickness of .102 inch. It will be understood that these dimensions are given for illustrative. purposes only and that they may be changed as may be desired.. The important pointto be made here is that the cross-sectional area of theV outer spring clip 5!! is less than the cross-sectional area oi' the inner spring clip 58.l for the reason above set forth.

As shown in Figure. 5, the smaller ends 52 of the pear-shaped contact ngers 53 are held apart sufficiently far so that the wedge-shaped blade 5.43 can pass therethrough without engaging either or them. These smaller ends 52 engage the forrrard surfaces of the flanges 54 as the contact arm E95 continues to move in the direction of the arrow 55. As shown in Figure 6, the contact iingers 53 are rockedV about the axes of the .pins 5.6 past a line 65. joining their centers to the over center position shown in Figure 3. As the contact fingers 53 are swung to a position past the line t5, both of the spring clips 58. and `Si)l are stressed to provide such contact pressurebetween the contact members 53 and the spring clips 58 and 60 as to insure proper current distribution therebetween and thereby resist the closing movement of the contact arm 49. Immediately after the contact ngers 53 have passed beyond the line 65 in the switch closing operation the spring clipsA 58 and 60 act to accelerate the final movement of the contact arm 4S: to the fully switch closed position. The inward movement of the contact ngers 53 is limited by the tongues 59. In this position as shown in Figure 3, the spring clips 58 and 60 cooperate to lock the contact arm 49 in the switch closed position. Since the construction at each end of the switch blade 36. is identical it will be understood that it is held locked in the closed position at each end by the means just described.

It is not intended that the circuit. shall be. opened or closed by separation of the wedgeshaped blade 58 from the contact ingers 5.3 or engagement therewith so as to draw an arctherebetween. Instead the circuit is opened and closed by means of the load interrupter. 33 that is associated with each of the stationary contacts 23 in a manner now to be described. It will' be understood that, when the switch blade 38 is in the switch closed position, the circuit extends between the. contact and terminal mounting brackets lI5 through the stationaryA contacts 29. carried thereby and the switch blade 36 interconnecting the same. In this switch. closedpoi sition the load interrupters 33 are out of circuit with the switch blade 36 although, if desired, they may be connected in parallel with the switch blade 3.6 and the stationary contacts Zitatv its ends.

The circuit is transf-erred to the loadV interrupter 33 at each end of the switch blade 36 by a disconnectingA contact 68 which is carried thereby and secured thereto by bolts 69. The disconnecting contact 68 preferably is in the form oi' a strip of Phosphor bronze which is highly resilient and` yet has good electrical conducting characteristics. It is bow-shaped and its outer surface is arranged to. eng-age a flange .10 that. is formed integrally with a housing 'Il of electrically conducting material, such as brass, which forms. a part. of. each oi the load interrupters 33.

As. shown more clearly in Figure 8 of the drawings, the housing 'H' is supported at one end 0f a porcelain insulator 'l2 which is secured ai; its other end to a fitting T3, which is secured by the bolts. 3.4: to. the angle.` clip 3;I. referred.' to-hereine before. Within the porcelain insulator l2, which is tubulary in form, is a sleeve '1.4 of insulating material, such as a phenolic condensation prod.N uct, which carries a stack l5 of iiber washers that are positioned so as to provide a bore l@ therethrough. Within. the bore 1G there is a plug-like bifurcated contact lil .which-,- in the. circuit closed position, is arranged .to have contact engagement with a ring-like stationary contact 'I8 that is threaded, as. shown, into the fitting 13 and thusA connected through .the angle clip 3l to the upstanding section 25 of the. associated contact and terminal mounting bracket I5. It will be observed that one end. of thesleeve '14` is threaded into the fitting 1'3 while its other end is threaded into a. suitable boss which eX- tends from the housing ll. Near its outerend a plug or follower T9 of insulating material is attached to the. contact 'l and is arranged to be moved therewith into the Vbore i5 formed in the stack `l5vof ber washers. As the contact 'il is drawn into the bore i6 and44 separates from the ring-like. stationary contacts "8 an arc iS drawn therebetween if the load current is iiowing in the circuit. The arc is drawn into the bore 1.8 and between it and the outer surface of the plug 19 which together constitute arc extinguishing means that, under the heat of the arc, are arranged to evolve an arc extinguishing medium which ilows into the arc space and deionizes the same.

rihe products of the arc drawn in thismanner and the arc extinguishing medium fiow through a cylindrical extension 82 ci. the stationary'contact 18. and into a condenser that is shown, generally, at 83. The condenser 83 isprovided for cooling and condensing the products of the arc, so that, when the same escape to the atmosphere, their temperature will be such as not to sustain combustion orto create an ionized conducting pathv between adjacent phases of the switch l).

Asv shown in Figure l, the condensers V88 at opposite ends of each of the switches li. extend in opposite directions while the condensersv 83y of adjacent switches l! extend toward the next switch li'. With this arrangementof the condensers 83 there is a minimum oi likelihood of an arc over between the adjacent switches Il resulting from the discharge from thek condensers 83.

As illustrated in Figure 8 each of the condensers 83l comprises a. sleeve or housing 84V of irietal. For example, the sleeve or housing 84 may be formed of a seamless tube. At its innel end it is secured to a ring 85 that, in turn, is secured to an adapter sleeve 86 which is threaded into the angle clip 3|. Near its outer end the sleeve or housing 84 is provided with a plurality of condenser plates 81 which extend transversely thereof. The plates 81 are formed of metaly such as brass, and they have apertures 88 that are formed therein by a stabbing operation which produces slivers 69 that extend therefrom and serve to space the condenser plates 81 apart. The condenser plates 81 are positioned in the sleeve or housing 84 so that the apertures 88 are out of registry with each other. The reason for this is to avoid a straight path therethrough for the products of the arc which flow into the sleeve or housing 84. The stack of condenser plates 81 is held in position in the sleeve or housw ing 84 at one end by a shoulder 9u which is formed by externally rolling a groove therein. It will be noted that the innermost plate of the stack of plates 81 reacts or bears against the adjacent surface of the shoulder 33. The outer end of the sleeve or housing 8d is provided with a closure plate 9| against which the slivers 35i of the outermost plate 81 engage. The plate Si is provided with apertures 32 through which the pressure generated within the sleeve or housing 84 can escape to the atmosphere.

The plug-like biiurcated contact 'il is moved through the bore 16 by a linkage which will be described now. At its inner end the contact '11 is secured by a pin 96 to a rst link t? which, in turn, is pivoted by a pin 63 on a second linl: 99. The second link 90 is pivotally mounted at on a suitable boss extending inwardly from the housing 1|. The link 539 has an extension I0| which bears against the adjacent surface of the housing 1| and thereby serves to limit the extent of inward or outward movement of the contact 11 as the case may be. The first link 91 is connected intermediate its ends by pin |02 to a third link |03 that is fast on a rock shaft |04. A coil tension spring between the rock shaft |04 and the pin 83 so as to provide an over center toggle construction which is effective to bias the contact 1l toward either the closed position shown in Figure 8, or the alternate position where it is separated from the stationary contact 13 and occupies the open position. In the open position the contact 11 is withdrawn through the bore 16 into the houS- ing 1 I.

As shown in Figure 'I the rock shaft lila exn tends to one side of the housing 1| and carries a bifurcated operating arm or lever that is indicated, generally, at |08. The arm or lever |08 has branches |08 and H0 which are offset from each other as shown in Figure 3. The branches |08 and IG are arranged to be engaged by an operator, shown generally at H2 in Figure 4, which is carried at the cuter end or the switch blade 33 and forms an integral part of the blade tip 41. The operator H2 includes a forwardly extending flange H3 which is shaped to conform to the shape of the branch |63 of the operating arm or lever |08 and is arranged to engage the same as the switch blade 35 is swung toward the switch closed position to roel; the shaft |04 and move the contact 11 from the open position to the closed position as shown in Figure 8. The operator II2 also includes a transversely extending flange H4, Figure 3, which is arranged to engage the other branch i3d entends ||0 when the switch blade 36 is moved toward the switch open position. This serves to IOck the shaft |04 `so as to move the contact 11 from the position shown in Figure 8 of the drawings to the open position in the housing 1|.

It is desirable that the operating arm or lever |08 be locked in the position shown in Figure 7 of the drawing so that the load interrupter 33 cannot be operated accidentally to the open position while the switch blade 3E occupies the closed position. Accordingly, there is provided a tail extension |I5 as an integral part of the blade tip 41. As shown in Figure 7, the tail extension ||5 is arranged to be positioned in the path of the f branch |09 of the operating arm or lever |00 and thereby insures that the latter cannot be moved as long as the switch blade 36 occupies the switch closed position.

In describing the operation of the gang operated switch construction I0 which is made up of 4the switches I I, it will be assumed first that they are in the closed positions as shown in Figure 1. The insulators 35 are rotated simultaneously by movement of the operating rod 44 to swing the switch blades 36 from their positions shown by full lines in Figure l to their positions shown by broken lines in `this same figure. During the initial movement of each of the switch blades 36 to the open position the pear-shaped contact ngers 63 at each end of each switch blade 36 are rocked the axes of their respective hinge pins 56 toward the line 65, Figure 6, joining the same. This flexes the outer ends of the spring clips 58 and 60 to stress the same additionally. During this interval the disconnecting contact 68 at each end of each switch blade 36 moves into engagement with the flange 10 of the associated housing 1| which forms a part of the associated load interruptor 33. This places the contacts 11 and 18 of each of the load interrupters 33 in parallel with the associated stationary contacts 29 and end of the switch blade 36. As the switch blade 36 moves to such a position that the pear-shaped contact fingers 53 move past the line 65, the energy which has been stored in the spring clips 58 and 60 is released and serves to accelerate the movement of the ends of the switch blade 36 toward the Switch open position. Thereafter the wedge-shaped blade 50 disengages the smaller ends 52 of the contact fingers 53 and the entire current ilow is then transferred to the load interrupter 33 at each end of the switch blade 36. As the switch blade 36 continues to swing toward the open position propelled by the accelerating spring in the spring operator 43 and the stored energy in the moving parts, the tail extension I5 is moved out of register with the branch |09 of the operating arm or lever |08 and thereafter the transversely extending flange II4 engages the branch IIO of the operating arm or lever |08 to rock the shaft |04 toward the open position to carry with it the plug-like contact 11. The continued movement of the switch blade 36 to the switch open position finally causes the Contact 11 to separate from the stationary contact 18 and to draw the arc therebetween into the bore 16 where it is eX- tinguished by the evolution of are extinguishing material from the stack 15 of iiber washers and the outer surface of the trailer plug 19. It is pointed out here that the rigid connection provided by the switch blade 38 between the operating mechanisms for the contacts 11 and 18 of the load interrupters 33 at the ends of the switch blade 36 serves to synchronize their operation so that they separate at substantially the same instant. Tests with 'an oscillograph show lthat the contacts'II and 18 o'f the :load interrupte'rs 33 'at the 'en-ds of 'a switch blade 36 operate within onetenth of 'a half cycle of i60 .cycle -alternating current. Tests Yalso show that an arc is drawn si- .multaneously .in l'e'achibore 16 of each of the load interrupter's 33 so that each inte'r-rupter 33 is called to interrupt V.the loadcurrent fat Vsubstantially one-half of the line voltage.

The construction of 'the load interrupters 33 is such that the arcs will be drawn tand-.extinguished therein vwhile the disconnecting contacts 66 .re- Vm'a'in'in engagement with'the'housings 'I.I. Thereafter, on continued 'movement'of the switch blade 36 to the openposition, the disconnecting contact 69 at each end disengages the associated housing 1I. The switch blades v36 finally are :swung `to their positions as shown by the 'broken .lines in Figure l where 4they .are located `at right .angles to their initial switch -closed positions. vIn lthis manner two air gaps areprovided ,for Yeach lphase since no connections Aremain between `the contact and terminal mounting brackets I5 and vparts associated therewith, the two .fairfgaps being inrovided therebetween and the switch blade 36 in the transverse open position.

When the switch blade 36 .isrn'oved to the closed position the operations -just described 'take place Vin reverse sequence. That is, the disconnecting contact 68 ateach end fof the switch `blade 36 nrst engages the .associated V'housing .II. Thereafter the forwardly Aextending flange `I Il3 o'feach of the bla-de tips 4`I engages the corresponding branch |09 of the associated operating arm orllever |08 kand rocks lthe shaft 104 past the rover center position and effects `mov'en'ie'n't o'f the -contact TI into engagement with the contact vi8, thereby `complating the circuit between the 'contact and terminal mounting brackets I5 'fthrough'the load interrupter switches 33. The `wedge shaped blade 50 of the contact arm S49 'at each end of the switch blade 36 .thenengages 'thesmaller ends 52 of the pear-shaped contact Jn'ngers 53, in the manner described hereinbefore, and they are moved to the position shown in Figure 3. In the fully closed position the contact fingers 53 are biased by `the Yspring clips 58 and 6.0 to lock the contact .arm 49 and ends of the switch blade 33 in the switch closed position. During its riinal movement the switch blade 36 shifts the disconnecting contacts 68 out of engagement with the housings II at each end, thereby removing the load interrupters 33 from the circuit.

Referring now particularly to Figures 1 and 2 of the drawings, itis pointed out that the stationary contacts 29 and load interrupter 33 at each end of the switch blade 36 are located substantially in parallel horizontal planes II6 and III which are at right angles to the longitudinal axis of each switch blade 36 when it occupies the closed position. The horizontal planes II6 and I I'I are indicated by the broken lines in Figures l and 2. The broken line IIB in Figure 3 designates both the longitudinal axis of the switch blade 36 and also the vertical plane in which it moves. By positioning the stationary contacts 29 and load interrupter 33 in substantially the same plane at each end of the switch blade 36 when it is in the closed position so that its longitudinal axis is at right angles thereto, the contact and terminal mounting brackets I5 and parts carried thereby may be located at a. minimum spacing with respect to each other for a given line Voltage. This provides a minimum length of switch blade 36 and thus reduces the torque which must be applied to each of the insulators 35 for .rotating it and the switch blade 36 carried thereby.

As shown in Figure 2 the load interrupters 33 at each end ci each switch 'blade 3B are located in the same Vertical plane which is indicated by the broken line H9. Likewise the stationary contacts 29 at each end of each switch blade 36 are located in a vertical `plane which is indicated by the broken line -I 26. IThe plane, indicated by the broken line i I8, in which the switch blade 36 rotates is between the planes krepresented by the broken lines IIS and 120. Also it will be noted that the planes represented bythe broken lines IIB, II9 and I20 are parallel to the plane represented by the broken line IZYI through the channel iron support I3.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it vis intended that all matter shown in the accompanyingdrawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

l. In a switch, in combination, a pivoted switch blade, a pair of round nosed contact fingers arranged to be engaged directly by said switch blade for completing a circuit therethrough, means rockably mounting said contact'ngers on opposite sides of the plane of movement of said switch blade about parallel axes in a plane at right angles to said plane of movement of said `switch blade so that the nose portions or" said Contact iingers engage opposite sides of said -switch blade with a rocking and wiping action, and spring means biasing said contact fingers toward each other, said switch blade in moving to and trom the switch closed position rocking said contact ngers from one side of said rplane containing their aXes to the other.

2. In a switch, in combination, a pivoted switch blade, a pair of round nosed contact fingers arranged to be engaged directly by said switch blade for completing a circuit therethrough, means rockably mounting said contact nngers on opposite `sides of the plane of movement of said switch blade about parallel axes in a plane at rightan- .gies to said `'plane of lmovement of said switch blade so that the nose portions c'f said contact fingers engage opposite sides of said switch blade with a rocking and wiping action, spring means biasing said contact fingers toward each other, stop means limiting the extent of movement of said contact ngers in either direction past said plane containing their axes, and abutment means on said switch blade engageable with the juxtaposed round nosed ends cf said contact nngers for rocking the same from one side of said` plane containing their axes to the other on movement of said switch blade to and from the switch closed position to effect the saine with a snap action and to lock said switch blade in the closed position.

3. in a switch, in combination, a pair of generally pear shaped Contact fingers, a generally U- shaped inner spring clip rockably supporting said contact fingers at its outer ends and acting to bias their smaller ends toward each other, a generally U-shaped outer spring clip nesting with said inner spring clip and bearing against the larger ends of said contact fingers to make electrical contact therewith and to urge the same additionally toward each other, said smaller ends of said contact iingers being rockable from one side of the plane through their axes of rotation away from said spring clips to the other side thereof, a switch blade arranged to enter the space between said smaller ends of said contact :lingers when they are on said one side of said plane and to be engaged thereby for completing a circuit therethrough, and abutment means on said switch blade reacting against said Contact fingers on further movement of said switch blade for rocking said contact iingers to said other side of said plane to increase the Contact pressure exerted thereby on said switch blade, to move said switch blade to its closed position with a snap action and to lock the same in said closed position.

4. In a switch, in combination, a pair of generally pear shaped Contact fingers, a generally 'rl-shaped inner spring clip rockably supporting said contact fingers at its outer ends and acting to bias their smaller ends toward each other, a detent near each end of each arm of said inner spring clip cooperating with the contact finger carried thereby to limit its inward movement, detent extending from the larger end of each contact finger and cooperating with the adjacent arm of said inner spring clip to limit the outward movement of each Contact finger, a generally U-shaped outer spring clip nesting with said inner spring clip and bearing against the larger ends of said contact fingers to make electrical contact therewith and to urge the same additionally toward each other, said smaller ends of said contact ngers being rockable from one side of the plane through their axes of rotation away from said spring clips to the other side thereof, a switch blade arranged to enter the space between said smaller ends of said contact ingers when they are on said one side of said plane and to be engaged thereby for completing a circuit therethrough, and abutment means on said switch blade reacting against said contact ngers on. further movement of said switch blade for rocking said contact fingers to said other side of said plane to increase the contact pressure exerted thereby on said switch blade, to move said switch blade to its closed position with a snap action and to lock the same in said closed position.

5. In a switch, in combination, a pair of generally pear shaped contact lingers, a generally l 12 Ll-shaped inner spring clip rockably supporting said Contact ngers at its outer ends and acting to bias their smaller ends toward each other, a detent near each end of each arm of said inner spring clip cooperating with the contact nger carried thereby to limit its inward movement, a detent extending from the larger end of each contact iinger and cooperating with the adjacent arm of said inner spring clip to limit the outward movement of each contactnger, a generally U- shaped outer spring clip nesting with said inner spring clip and bearing against the larger ends of said contact fingers to make electrical Contact therewith and' to urge the same additionally toward each other, said smaller ends of said contact lingers being ro'ckable from one side of the plane through their axes of rotation away from said spring clips to the other side thereof, and a switch blade arrangedto enter the space between said smaller ends of said Contact fingers when they are on said one side of said plane and to be engaged thereby for completing a circuit therethrough, said switch blade having transverse grooves on opposite sides into which said smaller ends of said contact lingers extend and against whose sides the same react'on movement of said switch blade to and from the switch closed position for rocking said contact fingers from one side of said plane containing their axes to the other to effect the same with a snap action and to lock said switch blade in the closed position.

6. The invention, as set forth in claim 5, wherein iianges extend from opposite sides of the switch blade along the rear sides of the transverse grooves to insure rocking of the contact fingers inwardly when said switch blade is moved to the closed position.

7. The invention, as set forth in claim 3, wherein the outer ends of the U-shaped outer spring clip move further apart than do the outer ends of the `U-shaped inner spring clip and the former has less cross-sectional area than the latter to accommodate such further movement.

SIGURD I. LINDELL.

References Cited in the file of this patent UNITED STATES PATENTS Number

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