US2306117A - Electric switch - Google Patents

Description

Dec. 22, 1942. J. P. DUNLAP 2,306,117

ELECTRIC SWITCH Filed April 24, 1941 6 Sheets-Sheet 2 6 Sheets-Sheet 3 J. P. DUNLAP ELECTRIC SWITCH Dec. 22, 1942.

Filed April 24, 1941 6 Sheets-Sheet 4 6 Sheets-Sheet 5 J. P. DUNLAP ELECTRIC SWITCH Filed April 24, 1941 Dec. 22, 1942.

Patented Dec. 22, 1942 ELECTRIC SWITCH James P. Dunlap, Chicago, Ill., assignor to Electric Manufacturing Company, Chicago, a corporation of Illinois Royal Application April 24, 1941, Serial No. 390,062

16 Claims.

This invention relates to electric switches and more particularly to switches of the type used in the transmission and distribution of power, especially switches of medium and high current carrying capacities. The principles of the present invention are particularly concerned with the construction of air break disconnecting switches wherein the switch blades and contacts are exposed to atmosphere and therefore sub.- ject to corrosion and also frequently exposed to rain, sleet, and the like.

An electric switch of the type here involved includes one or two movable parts adapted to be brought into and out of engagement with one another to open or close a line circuit or a portion of a line circuit. The switch includes a terminal for each switch member, which terminals are permanently connected to a line or the like and are also connected to the associated movable switch part, that is, the movable switch blade or movable switch contact, as the case may be. The use of flexible conductors for maintaining the circuit connection with a movable switch contact is objectionable. Such contacts must necessarily be of rather fine wire. Any corrosion of the fine wire results in a substantial decrease in the effective cross sectional area of of the remaining copper. Furthermore, the conductor is subjected to flexing during each switch closing and switch opening operation. This alternate flexing produces a hardening of the braided copper and therefore renders it more susceptible to breakage. I It is one of the objects of the present invention to eliminate the need of a braided copper or other flexible connection between the movable switch member and its associated terminal. This is accomplished, in one embodiment of the present invention, by mounting the movable switch member on a hinge or the like which makes a wiping pressure contact with a stationary stud or the like. In the preferred embodiment of the present invention theswitch contact comprises one or more flexible rods or wires freely flexible at their contact making end and supported at a point spaced from the contact making end. The wires may consist of copper -weld tubes, that is, a copper tube welded on a steel filling core. The wires may be clamped intermediate their ends so that both ends of the wires may be flexed out of their normal position. One end of each copper weld wire is contacted by the switch blade. The other end of each copper weld wire slides on and is flexed by a stationary contact stud which is connected to or I forms a part of the switch terminal and thus establishes circuit connections to the copper wire.

In one embodiment'of the present invention the switch contact is pivotally mounted and is moved by the switch blade to its alternate positions as the switch blade moves to open the switch circuit or to closeithe switch circuit. Since the switch blade constitutes the only means for moving the switch contact, the switch contact should remain in its switch open position, once it is moved to that position, until the blade is again actuated toclose the switch. It is one of the objects of the present invention to provide positive means for maintaining the switch contact in its open position as required. This is accomplished, in one embodiment of the present invention, by utilizing the springiness of the switch contact wire. The contact stud engaged by the contact wire is of a non-circular shape, so shaped that as the wire reaches its full open position a part of the stress on the wire is released. Any initial movement of the spring wire towards its switch closed position must result first in an increase in the spring stress on the wire. This efiectively prevents movement of the switch contact wires from their open towards their closed position by vibration, wind forces, gravity, or the like. In lieu of this, or in conjunction with it, means may be provided for forming a snap lock to hold the contact in its open position.

It is a further object of the present invention to provide improved means for counterbalancing the switch blade in a switch wherein the blade moves vertically.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawings, forming a part thereof.

In the drawings:

Figure- 1 is a side elevation of a vertical break type of outdoor disconnecting switch embodying the present invention;

Figure 2 is a plan view of the switch of Figure 1 with part of the structure broken away to illustrate the underlying parts:

Figure 3 is a sectional view taken along the line 3-3 of Figure 1;

Figure 4 is an enlarged sectional view of the switch contact taken along the line H of Figure 1;

Figure 5 is a sectional view taken along the line 5-5 of Figure 4;

Figure 8 is a plan view of a switch illustrating another embodiment of the present invention;

Figure 9 is a side elevational view of the upper part of the switch of Figure 8;

FigurelO is a view taken along the line ||0 of Figure 11;

Figure 11 is a sectional view taken along the line of Figure 10;

' Figure '12 is a perspective view of the contact carriage of the switch of Figure 8;

Figure 13 is a sectional view taken along the line |3|3 of Figure 11;

Figures 14 and 15 are views corresponding to Figures 10 and 11 and illustrating a modified construction;

- Figure 16 is a perspective view of the locking cam of the switch of Figures 14 and 15;

Figure 17 is a side view of the upper portion of a three insulator switch of the type shown in Figure 1, and illustrating another embodiment of the present invention;

Figure 18 is a sectional view of the contacting mechanism at the hinged end of the blade of Figure 17, said view being taken along the line |8|8 of Figure 19;

Figure 19 is a plan view of the hinged end of the blade and contacting mechanism of the switch of Figure 17; and

Figure 20 is a sectional view taken along the line 20-20 of Figure 19.

Reference may now be had more particularly to the switch illustrated in Figures-1 to 6 inelusive. This switch is an outdoor type vertical break disconnecting switch \of a rating of approximately 15,000 volts and six hundred amperes. The switch, indicated in general by the reference numeral I, includes a channel iron mounting base 2 on which are mounted two stationary insulators 3 and 4 and an axial rotatable insulator 5. The insulators may be mounted on the base in any desired manner. The mounting for the insulator includes a bearing 5. Means is provided for axially rotating the insulator 5 as, for instance, by a crank I. Ina three phase system three switches, such as shown in Figure 1, are mounted side by side, and the cranks l of the rotary insulators 5 are interconnected for simultaneous operation. The insulators 4 and 5 include insulator caps l0 and H suitably secured to the respective insulators. A bearing stud i2 is bolted or otherwise suitably secured to the insulator cap I the axis of the one end thereof for receiving a clamp for clamping a line conductor |l thereto.

An actuating crank I0 is bolted or otherwise suitably secured to the end of the stud |.2 so that upon rotation of the insulator II the crank I0 is rotated.

The hinge bracket l5 includes a pair of upstanding arms 20-20 having aligned'perforations or holes therethrough for receiving a pin 2| which is iournalled in the arms-20-20. A switch blade 25 is secured to the pin 2|. The switch blade consists of a blade carriage 26 secured to the pin 2|, a tube 21, and a contact stud being coaxial with the axis oi the insulator.

A back bearing l3, which is bolted to a supporting bar I4, is slipped over the stud l2 so that the stud can rotate while the supporting bar l4 remains stationary. The stud fits snugly through the bearing l3 so that there is only a slight amount of play between the supporting bar and the bearing. The opposite end of the bar I4 is bolted to a hinge bracket l5 which in turn'is bolted to the insulator cap I0. Thus the supporting bar braces the insulators 4-5 while permitting rotation of the insulator 5 with respect to the insulator 4. The supporting bar i4 is made of copper or other material of high current carrying capacity and is of suflicient cross sectional area for the current carrying capacity of the switch. The bar |4 constitutes one terminal of the switch and has a plurality of bolt holes at making cam 23, all of material of high current carrying capacity. The blade carriage 26 has a pair of arms 30-30 integral therewith and terminating at the rear of the blade in split clamps 3|-3| that flt between the arms 20-20 of. the hinge br'acket l6, as may be seen from Figures 2 and 3. The pin 2| is then inserted through aligned holes in the arms 20 and through aligned perforations in the split clamps 3|. The clamps are then tightened by then tightening nuts at the ends of bolts 33. This tightly clamps the blade carriage to the pin 2|, thus establishing a good electrical connection between the blade carriage and the pin.

Circuit connections from the line ii to the switch blade are established by way of the supporting bar l4, 9. contact rod casting .34 and six contact rods 35 which are secured to the casting 34 and press against the pin 2|. The contact rods consist of copper clad steel tubes.

The copper affords the necessary current capacity and the steel core aflords the necessary resiliency. The six rods 35 are press fitted into individual holes in the casting 34 and then secured in place by socket head set screws 38, thus establishing firm electrical and mechanical conare thus slightly spread apart by the pin 2| and exert a high spring pressure thereagainst. The circumference of the pin 2| is smooth so that upon rotation of the pin.2l the contact rods slide freely on the pin but maintain a high pressure thereagainst. thus maintaining electrical connection between the casting 34 and the pin 2| The blade carriage 26 has a pair of upstanding ears 4M0 integral therewith. A connection rod 4| is connected to the ears 40-40 by a universal coupling 42. The opposite end of the connecting rod 4| is connected to the crank l8 by another universal coupling 43. Thus upon rotation of the crank I! the connecting rod rotates the switch blades 35 vertically about the pin 2| 'as an axis. The switch blade moves from the switch closed position illustrated in full lines in Figure 1 to a switch open position illustrated in fragmentary portion by the dotted lines in Figure 1. It is to be noted that in'moving to the switch open position the blade passes through a vertical position and then moves slightly beyond its vertical position. As a result there is no tendency for the blade to fall from its open position to its closed position.

Means is provided for counterbalancing the weight of the switch blade, thus easing the asoaiir 3 switch opening and closing operation. This comprises two similar spring housings 88 each of which is bolted to one of the arms 88 of the blade carriage by a pair of bolts 41-41 to be rigid with the blade carriage. Each housing extends over and encloses the part of the pin II that projects beyond the arms 28-28 of the hinge bracket l8. A coiled torsion spring 8 sur rounds the projecting part of the pin ii in each spring housing. One end 88 of the spring extends into a small hole in the'spring housing 88. The other end 8| of the coiled spring extends into and is secured in a hole in thearm 28 of the hinge bracket i8. The two springs thus counterbalance the weight of the switch blade. Each housing 88 thus protects the springs from the weather and prevents the formation of ice and sleet thereon.

The contact making cam 28 of the switch blade is of a generally hollow rectangular formation and has a shank portion 88 that is press fitted or otherwise firmly secured in the tube 21 in firm electrical and mechanical connection with the tube 21 of the blade. The tube 21 may, for instance, make a shrink fit on the shank portion 88. The contact making cam includes a cam portion 88 which is rounded and of a generally elliptical or oval cross section in vertical section. The'cam portion 88 is adapted to be moved into and out of engagement with a contact structure 88 that is pivotally mounted on the insulator 8 and connected to the opposite terminal of the switch.

A description will now be given of the construction of the contact structure 88. The insulator 8 has an insulator cap 82 suitably secured thereto in the usual manner, to which is bolted a contact base and terminal 88. base includes a circular portion 88 for bolting to the insulator cap, from which circular portion there rises an inclined portion 88 terminating in a rectangular bar portion 88, all of which constitutes one rigid casting. The bar portion 88 is the terminal of the switch and is provided with holes for receiving a line conductor which may be clamped or otherwise secured thereto in any desired manner. The-bar portion 88 has an upward and forwardly extending portion 81 that terminates in a cam portion 88 having a horizontal pin receiving hole for receiving a pin or stud 18 that swivels a contact rod bracket or carriage 1| to the contact base. The carriage 1| has a pair of arms 12-12 that embrace the portion 81, and have aligned holes therein for receiving the stud 18. The contact rod carriage has a head portion 19 extending above and below the arms 12, as may be seen from Figures 1 and 5. The head 13 has six rod receiving holes therein in two rows of three aligned holes in each row. Upper contact rods 15 and lower contact rods 18 are press fitted through the holes in the head 18. The rods 18-18 consists of steel cores within copper jackets, whereby the copper aifords the necessary current carrying capacity and the steel affords the necessary resiliency or springiness. The press fit of the rods in the respective holes inthe head 13 assures establishment of a firm electrical and mechanical connection between the rods and the carriage.

The rear ends of the rods embrace the cam portion 88 and are slightly spread apart by the cam portion whereby the springiness of the rods causes the rods to exert a high pressure against the cam portion 88, thus maintaining firm elec- The contact trical connection with the cam portion. When the contact structure 88 is in the switch closed position as illustrated in full lines in Figures 1 and 5, the contact rods engage the surfaces 18-19 of the cam portion 8 8. The distance between these surfaces is in excess of the distance between the rows of rods 18-18 so that the cam portions 18-18 spread the rods apart, thus stressing the rods and causing the rods to exert a spring pressure against the surfaces 18-19 to maintain firm electrical connection with those surfaces. when the contact structure is moved to the switch open position in a manner to be more fully set forth as this description proceeds,- the rods slide along the surfaces 18-18 and ultimately come into engagement with the surfaces 88 and 8|. These surfaces are a distance apart slightly less than the distance between the surfaces 18- -3, the difference being sufficient to produce an appreciable relief in the stress on the conducting rods. The conductin rods are then not spread apart at all by the surfaces 88-8i. Thus when the carriage is moved to the switch open position, which is the position illustrated in dot-dash lines in Figure 5, the contact rods tend to maintain the carriage H in its elevated position, the stiffness of the contact rods preventing the contact rod carriage 1| from moving to the full line position of-Figure 4 where the ends of the contact rods would be spread apart by the cam surfaces 18-19.

In the operation of the switch it is essential that once the switch blade has been moved to the open position and has moved the contact' structure 88 to the open position, the contact structure must'stay in its open position until it is moved to its closed position by the switch blade. There must be no reasonable possibility of the movement of the contact structure to its switch 'closed position by wind, accompanied by vibrations, or other extraneous causes. Additional means is provided for assuring holding of the contact structure in its switch open position. This additional means comprises a looking cam lug 88 having curved cam surfaces 88-81 a distance apart greater than the distance between the nearest surfaces of the upper end contact rods 88-88. Thev two outermost rods in the top row of contact rods are longer than the other four rods and extend beyond the cam portion 68 to overlie the locking cam lug 88. When the contact structure is moved to its open position the end contact rods 88-88 are first spread apart horizontally by the curved portions 86-81 of the cam lug and then snapped back into the curved portions 98-88 of the locking cam lug 85, as illustrated in dot-dash lines of Figure '1. These two end rods 88-88 thus serve to hold the contact structure 88 in its switch open position against the action of extraneous forces such as wind, vibration or the like, and yet allow switch closing movement by action of the switch blade, due to the fact that the contact rods are sufficiently resilient to permit spreading of the rods 88-88 to clear the surfaces 88-81.

From Figures 1 and 6 it-may be seen that the ends of the contact rods of the contact structure 88 are flared outwardly along smooth curves. This facilitates the switch closing operation. V

An explanation will now be given of the mode of operation of the switch thus far described. To open the switch the insulator 8 is rotated axially, thus rotating the crank i8 which causes the connecting rod I to pull upon the cars 40 of the blade carriage 26 to swing the switch blade from the full line position to the dotted line position of Figure 1. As the switch blade moves upwardly the cam portion 56 forces the contact structure 60 to swing about the pin or stud I0. When the contact structure 60 reaches the position illustrated in dotted lines in Figures 1 and 4 the cam 58 clears the contact rods of the contact structure. The switch blade continues to move towards its full open position while the contact structure remains in the position illustrated in dotted lines in Figures 1 and 5, which is the full open position of the contact structure. when the switch is closed the center line of the contact structure and the center line of the switch blade are in toggle position. This facilitates the switch opening operation, especially if the switch opening operation is to take place when the switch is coated with ice or sleet.

During the switch closing operation the reverse action takes place. The switch blade moves towards its closed position without alIecting the contact structure 60 until the cam 00 engages the lower row of contact rods It. Further movement of the switch blade causes the contact structure to swivel about the pin I0 from the dotted line position to the full line position. The cam 56 exerts a powerful camming action to spread the rows of contact rods IS-I0 apart and to scrape away any film of dirt or oxidefrom the rods at the place of contact whereby a high pressure at clean contact areas is obtained. I

It is to be noted that there are no braided or laminated conductors for extending circuit connections to the swinging switch blade or for extending circuit connections to the swinging contact structure 60. Such braided or laminated conductors have been a constant source of trouble because repeated openings and closings of the switch have resulted in breaking or tearing of the laminations. In the switch'of the present construction all circuit connections between relatively movable parts aremaintained by sliding connecting fits. This permits the camming action of the switch blade at the contact structure 60 on the initial switch opening operation, with a resulting powerful ice breaking action. without at the same time encountering the disadvantages inherent in the use of flexible braided conductors between the line and the associated pivoted contact member or contact making member. Furthermore, the spring housings 46 protect the counterbalancing springs from ice and sleet formation which would otherwise interfere with the switch opening operation.

The switch is provided with arcing horns as is usual. To this effect a copper clad rod 04 is pressed into a hole in the bar and secured in place by a pair of set screws. A cooperating rod 95 is secured to the switch blade 25. The rod 95 slides on the rod 94 during switch opening operation and slides out of contact therewith after the cam 56 has separated from the contact structure 60.

Reference may now be had more particularly to the switch illustrated in Figures 8 and 9. This switch is of the double break type and includes two contacts mounted on stationary insulators and adapted to be bridged by a switch blade mounted on an axially rotatable insulator located centrally between the two stationary insulators. The three insulators of this switch are indicated at I00. IOI and I02, of which the in Figures 10 and 11.

insulators I00 and I02 are stationary and the insulator IOI axially rotatable. The three insulators are mounted upon a supporting base in any desired manner as, for instance, in the same manner as' are the stationary insulators and the rotary insulator of the switch of Figure 1. The insulators I00 and I02, and the respective contacts associated therewith, are of identical construction. A description of one will therefore sufiice also for the other. Each insulator I00-I02 has an. insulator cap I03 suitably securedthereto. A contact support I05 having a circular portion I 00 is bolted at its circular portion to the insulator cap I03. The contact support includes aline terminal bar portion I01 having an upraised 'circular part I00 from which extends centrally a stud or shank I00. Acontact rod carriage I II is mounted to rotate about the shank I03. This carriage includes upper and lower arms 'II2-II3 having holes Ill and H5 therein of diflerent sizes but centered on the same axis. The arm H3 is slipped over the shank I03 until the upraised circular portion I00 enters the hole IIS. At that time the upper arm II2 rests upon the top flat surface I" of the shank I03. and a short stud portion III of the shank enters into the hole Ill. The contact rod carriage III is thus pivoted about the shank I09. A short bolt I20 threads into the shank I03 and holds the contact rod carriage III against upward movement without preventing rotation of the contact rod carriage. At its forward end the contact rod carriage or bracket III includes a block I 22 integral with the arms II2I I3 and having a bolt receiving'hole I23 extending therethrough. Contact fingers I25--I25 are bolted to the opposite surfaces of the block I22 by a bolt I26. The contact fingers I25-I25 serve to clamp four cop- 'per weld contact rods I28-I20 and I29I29.

, rods I 28-l 29 are outwardly fiared, as is apparent from Figures 8 and 10', and the rods I28 are slightly longer than are the rods I20. The opposite ends of the rods I 28-I 29 embrace the shank I08 and are bowed away from one another slightiy by the shank whereby the rods exert a firm pressure against the shank. The carriage III and contact support I05 including the shank I09 are made of material of high current carrying capacity. As a result the shank I09 extends the circuit from a line terminal bar portion I01 to the contact rods I20-I29.

A tubular switch blade I33 is rigidly secured to the top of the insulator cap on the insulator I M in any desired manner as, for instance, by being clamped .thereto. To each end of the tubular blade I33 there is secured a cam type contact making structure I34. The contact making structure I34 has a shank I33 that makes a snug fit within the tube of the blade I33, as illustrated A firm mechanical and electrical connection may be obtained between the tube I33 and the shank I 36 in any desired manner as, tor instance, by shrinking the tube I33 onto the shank I36. At one end the contact making member includes a contacting cam I30 which extends between the rods I23--I29 and spreads them slightly. As a result the rods exert a high pressure against the cam I33 and thus maintaingood electrical connection between the contact rods and the contact making cam I30.

contact rods I20 instead of two of. each as in the The contact making structure I34, including cam I30, is made of material of high current carrying capacity suitable for switch use. I

To open the switch illustrated in Figure 8 the insulator IOI is rotated in a clockwise direction, thus rotating the switch blade I33 in the same direction. The cam I30 forces the contact rods I20 and the associated contact rod carriage III to turn about the shank I as a center. This action continues until the contact rod carriage and the rods I28I23 reach the position illustrated in dotted lines in Figure 8. At that point the cam clears the contact rods I20-I20 and the continued movement of the switch blade III towards its open position results in separation of the blade from the contact structure including the rods I28-I28.

During the time the switch blade is in its open position the contact rod carriage III should remain in its open position as illustrated in dotted lines in Figure 8. To assure this the shank I00 is of a star shape in cross section, as illustrated in Figure 10. The contact rods ilk-I20 engage the shank surfaces I40-I44 when the switch is closed. These surfaces are a distance apart slightly in excess of the minimum distance between the back ends of the contact rods III- I29. .When the switch is open and the contact rods I28-I29 are in the dotted line position, illustrated in Figure 10, the contact rods I23 extend between the surface I40 and a surface I45, whereas the contact rods I29 extend between the surface I44 and a surface I45. The rods are now a distance apart slightly less than the distance between the surfaces I40-I44. As a result, if an attempt is made to move the contact rod carriage II from its dotted line switch open position to its full line switch closed position, it is necesary to force the contact rods apart slightly at the surfaces I40I44, against their natural resiliency. This requires an appreciable force. Therefore, there is no tendency for the contact rod carriage to shift from its open position to its closed position under the action of wind or vibration.

To close the switch the insulator IOI is rotated in a counter-clockwise direction. When the cam I38 rotates beyond its point of engagement with the contact rods I29 it forces the contact rods and the contact rod carriage III to swing about the shank I09, and at the same time it cams itself into position between the contact rods I20 and I29 and slightly separates the contact rods. As a. result the contact rods exert a very high pressure against the cam I33. Furthermore, during the sliding action of the cam I30 on the rods I28-I29 the cam wipes away any dirt or oxide film from the points of contact between the cam and the respective contact rods. There is thus obtained a clean, high pressure, point to point contact between the switch blade and the contact rods. When the switch is closed the circuit switch of Figures 10 and 11. The shank I03 is a cylindrical shank. two-sides of which are milled fiat, as indicated at ,I50-I5I. When the contact rod carriage III, which corresponds to the contact rodcarriage III of the switch of Figure 8, is in-its switch closed position the rods I25-I29 are slightly spread apart by the shank I00 and exert a high pressure thereagainst. When the carriage reaches its open position, indicated in dotted lines in Figure 11, the rods I'M-I20 are.

permitted to come closer together against the milled surfaces I50--I5I. This serves to hold the contact rod carriage in its switch open position. In addition, the lowermost contact rod in the row Illis elongated at its rear, as indicated at I53.

The elongated portion I53 cooperates with a locking cam I54 of a construction such as is illustrated in Figure 16, for yieldingly holding the carriage III in the switch open position. The locking cam I54 is bolted or otherwis rigidly secured to the bar I01 and includes a finger I 1 having a cam surface I55. As the carriage III swings from its switch closed position to its open position the rod I53 rides up on the surface I55, therod flexing upwardly under the action of the cam surface I50. As the carriage reaches its full open position the end I53 of the contact rod snaps into a circular depression I51 in the looking cam I54, thus resiliently locking the contact rod carriage in its open position. If an appreciable pressure is exerted against the lowermost rod I28 tending to turn the carriage III from its switch open position to its switch closed position, the end portion I53 of the lowermost rod will flex upwardly to rideover the cam surface I54 to free the carriage for rotation towards its closed position.

The switch blade I33 of the switch of Figure 14 has a contact making structure I34 similar to that of the switch of Figure 1, secured thereto in the same manner-as was previously described in connection with the switch of Figure 1. The contact making portion I34 includes a cam I38 which enters between the contact rods I28-I29 and spreads them apart slightly, against their natural resiliency, and thus maintains a firm pressure engagement between the contact rods and the cam portion I38 of the switch blade. Thus duringthe switch closing movement the cam exerts a powerful force upon the contact rods, so that only a very slight flexing is necessary in order to obtain the requisite pressure extends from the line at one of the bar portions I I01, through the shank I03, to the contacting between the contact rods and the cam portion Reference may now be had more particularly to Figures 1'1 through 20, illustrating still another embodiment of the present invention. Insofar as this switch is the same as the switch of Figure 1 similar reference numerals have been used. This switch embodies a different type of contacting mechanism at the hinged end of the blade, which contacting mechanism is particu-' larly useful for switches of ver high current carrying capacity, say, 1200 amperes and upwards. The switch includes two stationary in sulators 3 and 4 and an axially rotatable insulator 5, all mounted on a base in the same mannor as is the switch of Figure 1. The contacting structure on the cap' of the insulator 3 is substantally the same as that of the switch of Figure 1, differing therefrom essentially in that a larger number of contact making wires are used.

Insofar as the structures are the same, simii-ar' reference numerals designate similar parts.

' the rotary insulator of the carriage H In the switch or Figure 1': the arcing horns have been omitted merely to simplify the illustration,

it being understood tha arcing horns may be 'used if desired. A blade hinge bracket III ishalted or otherwise suitably secured tothe cap of the insulator 4 and includes a pair of arms I1II1I curved at their upper ends, as indicated at I12, for receiving a pivot pin I13. This pivot pin I18 passes through the arms "I of the bracket and through a pair of arms I1l-'-I 1! of a blade supporting I1 in which a tube 21 is inserted to constitute theswitch blade II. The blade carriage lilthas a pair ofupstanding arms 40' that are connected by a connecting rod 41 and universal couplings 42-43 to the crank II that is rotated by actuate the switch blade in as was previously described in connecion with the switchofFigure l.

The arms "5-"! of the blade supporting carriage are joined by a cam bar I18 which is an integral part of the casting constituting the blade supporting carriage I16. A pair of spring seats I18 are mounted on the pin I13 between thearms I1II1I and supports counterbalancing spring I". One end of the spring passes through a hole III in the web of the blade hinge bracket I10. The other end of the spring passes imder a pin III that extends from one of the arm I15 of the blade supporting carriage. The

' spring thus constantly forces the blade carriage upwardly to counterbalance the weight of the carriage. Y I

The stationary insulator l. and the rotary insulator I are secured-together by a bar It that is bolted to the blade hinge bracket I and aaoauv 2. Thus at that time the crank exerts a very P werful force on the switehbladeand there'is no great 'diiiiculty in overcoming the frictional resistance between the rods- Ill-I01 and the cambar I18. Thereafter, as the crank it moves out of position of toggle with the connecting rod 4|. the wires exert no appreciable pressure upon the insulator 5 to;- the same manner- 2o therods, orthe cam I10,

- flexure of the in which the pin at the upper end of the cap of is joumaled, as in Figure 1. The bar It is made of material of high conductivity and receives the line terminals II. A hinged contact block casing 34' of material of high conductivity is bolted or otherwise rigidly secured to the bar I4 electrical contact therewith. The casting 34' includes a cam portion I 84 that is embraced by the arms 12' of a carriage H. The carriage 1i is of a construction substantially identical with the construction of the carriage 1|, differing therefrom essentially in that to support a larger number of contact making wires in each of the two rows. The carriage 11' is hingedto the cam portion I and secured in place by a pair of bolts to permit oscillation about the center I85. The carriage 1I' supports two rows of contact wires each row of which contains, in this instance,

seven wires. The two rows are indicated at I 86 and I81, respectively, so that the wires exert a firm spring pressure against the two cams; A circuit is thus established from the line terminal, through the bar ll and casting 34', through the rowsof wires Ill and I81, to the cam bar I" of the switch blade blade. I

when the blade is the blade carriage a center to its open and thus to the switch actuated to open the switch swings about the pin I13 as position. As the cam bar I18 swings downwardly it first releases the pressure of the cam bar on the rods or wires m m, swinging the carriage H with it. The carriage H, of course, swings'about the center I" of the cam I as a center. The initial pressure of the rods lit-I81 on the cam bar I1. is released aftera small amount of turning of the in firm mechanical and it is of greater width t e switch blade.

The carriage U, will be held in its lowermost position-by gravity. when the switchblade is actuated to close the-switch the cam bar I10 enters between the rods Iii-I81 and swings them to the position illustrated in Figure 18. If

with ice or sleet the cam I1l' will break through ice as it forces the contact rods Iii-I81 apart when the switch blade approaches its full closed position. The cam I is also constructed so as to release the pressure on the rods lit-I81 when the carriage 1i .makes its initial movement towards its switch open position.- This will also result in breaking away any ice or sleet that may have formed on the cam I84, or the -.rods m-m, during the switch open period because the bars. are flexed apart shortly before they reach their full switch closed position. The rods or-wires m |s1 will result incracking have formed thereon at the ends thereof.

In compliance with the requirements of the patent statutes I have here shown and described a few preferred embodiments of my invention. It is, however, to be understood that the invention is not limited to the precise constructions here shown, the same being merely illustrative invention. What I conand desire to secure by Letters Patent 1. An electric switch including a contact member includinga spring contact rod pivotally mounted and havinga switch open position and a switch closed position, a contact making member movable into and out of engagement'with the contact rod and moving the contact rod to its alternate positions, said members being in a position of toggle when the switch is closed and said contact being swung through a substantial angle by the switch opening movement of the contact making member, and means engaging said rod for resiliently holding the contact member in its switch open poistion out of engagement with one another.

2. In an electric switch having a pivoted switch bfad means for establishing electrical connection between the switch blade and aswitch terminal, said means comprising a terminal'stud stationary with respect to the terminal, a contact rod bracket mechanically separate from the blade and pivotally mounted to-swing about an axis parallel to the pivot axis of the blade, at contact rod secured to the bracket and slidably engagsider new i a ing the stud and exerting a spring pressure thereswitch blade. Thereafter the wires exert no apagainst, said contact bracket and slidably bracket being moved from a switch closed position to a switch open position by the contact rod as the blade. moves to its alternate positions and presses the rod toits alternate positions.

3. In an electric switch having a pivoted switch rod extending beyond the and breaking of any ice that may while the two members are engaging the blade, said aaoanr blade, means for establishing electrical connection between the switch blade and a switch terminal, said means comprising a terminal stud stationary with respect to the terminal, a contact rod bracket mechanically separate from the blade and pivotally mounted to swing about an axis parallel to the pivot axis 01 the blade, a contact rod secured to the bracket and slidably enmeans for holding the bracket in its switch open position to which it is moved by the blade.

4. In an electric switch having a pivoted switch blade, means for establishing electrical connection between the switch blade and a switch terminal, said means comprising a terminal stud stationary with respect to the terminal, a contact rod bracket mechanically separate from the blade and pivotally mounted to swing about an axis parallel to the pivot axis of the blade, a contact rod secured to the bracket and slidably engaging the stud and exerting a spring pressure thereagainst, said contact rod extending beyondthe bracket, the blade being movable into and out of engagement with the rod, said bracket being moved from a switch closed position to a switch open position by the contact rod as the blade moves to its alternate positions and presses the rod to its alternate positions, and snap looking means engaging the rod in its switch open position and holding the carriage against movement to its switch closed position.

5. An electric switch contact including a pivoted contact rod carriage, a plurality of spring contact rods secured to the carriage with their axes at substantially right angles to the pivot axis of the carriage, each rod being free of the carriage at the two ends of the rod, a stud slidably engaged by one end of each rod as the carriage pivots about its axis, and means cooperating with at least one of the rods for holding the rod and through the rod holding the carriage in the switch open position.

6. In an electric switch, a contact stud, a rod carriage pivoted on the stud, a plurality of contact making rods mounted on said carriage intermediate their ends, a contact making member movable in engagement with the rods on one side of the carriage and pressingv said rods towards'the switch closed position and by the pressure exerted through the rods, swinging the carriage about the stud from a switch open to a switch closed position, the portions of the rods on the opposite side of the carriage making sliding pressure engagement with the stud for extending the circuit connection from the stud to the contact making member.

7. In an electric switch, a switch blade mounted for swinging movement at one end and having a contact making member at the opposite end, a curved conducting cam constituting a rigid part of the blade adjacent the mounted end thereof. and a plurality of conducting rods of spring material pressing against said curved conducting cam and making a sliding fit therewith for maintaining circuit connections to the blade, said cam exerting a camming action on the rods as the blade is swung from its switch open position to its switch closed position.

8. An electric switch including a mounting bracket having a pair of arms, a blade carriage having a pair of arms extending between the arms-of the bracket, a pivot pin rigid with the blade carriage and extending throughand rotatable in the bracket arms and constituting a pivot support for the blade carriage, the pivot pin being 01 material oi high electric conductivity, spring conducting rods pressing against said pin between the bracket arms, said pin sliding with respect to the rods as the blade carriage pivots between the arms of the mounting carriage for maintaining electric circuit connections with thecarriage, separate spring housings secured to each carriage arm, the housings closely embracing the bracket arms, andblade counterbalancing springs in said housings.

9. An electric switch including a mounting bracket having a pair or arms, a blade carriage having a pair of arms extending between the arms or the bracket, a pivot pin extending through and rotatable in the bracket arms and constituting a pivot support for the blade carriage, separate spring housings secured to each carriage arm, the housings and the carriage arms closely embracing the bracket arms, and blade counterbalancing springs insaid housings.

10. In combination with an electric switch blade member, a supporting bracket member to which the blade is pivoted, one oi. the members having a pair or arms embracing the other member, a pair of spring housings secured to and overlyingthe outer sides of the arms at the of rotation of the blade, and blade counterbalancing springs in said housings.

11. In combination with an electric switch blade, means for pivotally supporting the blade for swinging movement, said means including a supporting bracket having a pair of arms embracing the blade, a pair of spring housings secured to the blade, the spring housings overlying the outer sides of the arms at the axis of rotation of the blade, and blade counterbalancing springs in said housings.

12. In an electric switch, a contact structure including a contact stud, a contact rod carriage pivoted to swing about an axis extending through the stud, and a plurality of contact rods mounted on the carriage and slidably engaging the stud and exerting a spring pressure thereagainst,, said stud being a cam which changes the spread of the rods when .the rods are in a certain position a on the stud as the rods slide on the stud.

13. In an electric switch, a contact structure including a contact stud, a pivotally mounted contact rod carriage, and a plurality of contact rods mounted on the carriage and slidably engaging the stud and exerting a spring pressure thereagainst, said stud being circular in cross section with a part of the periphery thereof slabbed oil to reduce the effective thickness oi! the stud at the slabbed oi! part thereof, whereby the stud constitutes a cam tending to hold the carriage in the position where the rods engage the stud at the slabbed oil. portion thereof.

14. In an electric switch, a contact structure including a contact stud, a contact rod carriage mounted for pivotal movement about the center of the stud as an axis, a plurality of resilient contact rods mounted on the carriage and slidably engaging the stud, and a locking cam over which one of the rods springs as it reaches one limiting position for resiliently holding the carriage in said limiting position.

15. In an electric switch, a contact structure including a contact stud having a pair otspaced surfaces which are circular and on the same axis, a contact rod carriage having a pair of arms, said arms being journalled about said surfaces of the surfaces which are circular and on the same axis, 10

a contact rod carriage having a pair oi arms, said arms being journalled about said's'urfaces of the contact stud, a plurality 01' contact rods carried by the carriage and slidably engaging the stud I and exerting a spring pressure thereagainst, at

least one end rod extending beyond the stud, anda locking cam over which the last mentioned rod springs as it reaches its limiting position.

sauna P. DUNLAP.

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