US3069519A - Electrically operated switch - Google Patents

Description

1962 E. H. WATERS 3,069,519

ELECTRICALLY OPERATED SWITCH Filed April 5, 1960 5 Sheets-Sheet 1 INVENTOR Edward H. Waters ATTORNEY Dec. 18, 1962 WATERS 3,069,519

ELECTRICALLY OPERATED SWITCH Filed April 5, 1960 3 Sheets-Sheet 2 l I 47 '1 I 34 I I so 6M I I I O 39K. 9|

45 I, I 6'5 E I! E Dec. 18, 1962 E. ,4. WATERS 3,06

ELECTRICALLY OPERATED SWITCH Filed A m 5. 1960 s Sheets-Sheet s United States Patent Ofitice 3,959,519 Patented Dec. 18, 1962 3,069,519 ELECTRIQALLY OIERATED SWITCH Edward H. Waters, Bloomington, Ind, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsyivania Filed Apr. 5, 196i), Ser. No. 20,654 Claims. (Cl. 200-106) This invention relates generally to electric switching equipment, and more particularly to switches of the electrically operated type.

In many switching applications, such as the switching of capacitors in response to voltage variations of a system, it is desirable to have an inexpensive switch structure which may be electrically operated in response to such variations and which may have very fast contact separation to provide for restrike free switching of capacitor banks. It is also desirable to provide a contact mechanism having longer life and lower maintenance. It is further desirable that the switch be capable of withstanding large momentary inrush currents that occur in capacitor switching.

Accordingly, it is an object of this invention to provide a switch having a trip solenoid connected to swiftly drive a simple lever type operating means, which, in turn, drives the contacts to the fully opened condition.

More specifically, it is an object of this invention to provide in a switch a trip solenoid operable to drive the operating mechanism to the fully opened condition and wherein a limit switch operated by the operating mechanism at the end of a contact separation operation deenergizes the trip solenoid.

' It is another object of this invention to provide a novel contact mechanism having the movable contacts and fixed contacts mounted upon a common support to assure alignment between the contacts.

More specifically, it is an object of this invention to provide in a circuit interrupter, a contact mechanism wherein initial contact is made on the tips of the contacts, which contacts are wiped clean as the closing cycle is completed to thus minimize resistance.

It is a further object of this invention to provide in a circuit interrupter a contact structure providing for striking action on one part of the contacts during a closing operation and conduction through another portion of the contacts at the end of the closing operation.

Other objects will, in part, be explained hereinafter and will, in part, be obvious.

For a more complete understanding of the invention, reference may be made to the following detailed description, which may be read in conjunction with the accompanying drawing, in which:

FIGURE 1 is a vertical cross-sectional view of a switch illustrating one embodiment of the invention;

FIG. 2 is a fragmentary and elevational view of the switch of FIG. 1;

FIG. 3 is a perspective view of the limit switch assembly shown in FIG. 1;

FIG. 4 is a sectional view of the operating shaft and lever of the limit switches of FIG. 1, showing the relationship between the cams on the operating lever rod and the respective limit switch arms; and

FIG. 5 is a sectional view of the switch taken substantially along the lines V-V of FIG. 1.

, Referring to FIG. 1, it will be seen that this invention may be embodied in a switch generally of the type disclosed in Patent No. 2,701,828, issued February 8, 1955 to A. W. Edwards and Alvin W. Ogg and assigned to the same assignee as this application.

In the switch mechanism of the previously mentioned patent, a first solenoid closes the switch and a second solenoid is utilized to trip the toggle mechanism of the contact operating mechanism to allow the contacts to fall open under the pull of gravity. In capacitor switching, this may result in opening speeds which are too slow to prevent restrike conditions in the capacitor banks. To retain the simple, dependable solenoid operated contact operating mechanism of the prior patent and at the same time increase the speed of contact separation without adding costly means for storing energy in springs during the contact closing operation, the present invention utilizes the trip solenoid to drive the contact operating mechanism to, in turn, swiftly drive the contacts to the fully open condition. Limit switch means are added to deenergize the trip solenoid in response to the contact separation operation of the contact operating means.

A switch 17 is enclosed within a metal tank 27, which is provided with an insulating liner 28,- and which is surmounted by a top casting 29. An incoming line enters through a bushing 31 which terminates inside the tank as a conducting stud 34 which is electrically connected to fixed contacts in a manner hereinafter described in detail. The switch 17 has two bushings, each with a conducting stud 34, 35 passing through the bushing and each terminating, at its bottom for electrical attachment to fixed contacts, but since FIG. 1 shows an approximate central section through the switch, the second bushing and stud 33,- 35, respectively, are not visible in FIG. 1 but are shown in FIG. 2.

The contact assembly is comprised of fixed contacts and movable contacts mounted on a common support attached to the top casting. Specifically, a pair of elon gated support members 36, 37 each having an offset portion 38, 39 at the lower end, are suspended from bosses 40, 41 in the top casting 29, as by bolted brackets 42, 43 so that the supports extend downwardly between the previously described bushings 31 and 33. The supports are constructed from any suitable insulating material and are mounted in parallel relationship by means of a pair of spacers 44, 45 connecting the supports together at the top and bottom, respectively. Each of a pair of fixed contact mounts 46, 47, comprising an elongated fiat conductor, is attached to the outside of one of the supports 36, 37, respectively, so as to lie partially on the upper'portion of the support and partially on the oifset portion 38, 39, respectively, of the supports 36, 37. Each mount includes an integral stud 48, 49 on the upper portion for directly supporting the fixed contacts as hereinafter described, and includes an integral connector 50, 51 on the other portion. Each connector is attached to one of the hereinbefore described bushing studs 34, 35, respectively, as by nuts.

A stationary contact assembly is provided on each mount 46, 47, each assembly comprising a pair of opposed fingers 52, 52 and 53, 53 respectively, each pair of finger contacts having its corresponding members held at the upper end in opposed gripping relationship with the corresponding stud 48, 49 by means of compression springs 54, 54 and 55, 55, each pair of springs encircling a pin 56, 57 extending through the central portion of corresponding pairs of finger contacts, each spring being compressed between one of the finger contacts and a washer and pin assembly 58, 58 and 59, 59 at each end of each pin 56, 57. The lower ends of the finger contact pairs have elongated contacts on the inward side and are flared outwardly and downwardly with respect to each other. This structure effects a gradual spreading apart action of the finger contacts of each pair under the ima pact of the movable contact means, hereinafter described,

forced upwardly between the fixed contact finger pairs.

' The movable contact assembly is provided for engagement with the fixed contacts and comprises a pair of parallel insulating support bars 6%, 61 each connected I at "one end to the offset portions 38, 39 of'the'siipports 36, 37 by means of a common pin 62 connected between the insulating support members 36, 37, the other ends of the support bars being connected together by a spacer bracket 63. An elongated bridging contact member 64 having an upwardly extending tapering striker member 66 at each end, only one striker member being visible in the drawing, is fixedly attached to the bracket 63 perpendicular to the contact bars 60, 61 so that the movable contact strikers 65, 66 may each become simultaneously engaged between the corresponding fixed contact fingers when the contact bars 69, 61 are pivoted upwardly about pin 62 to a horizontal closed position, as shown in FIG. 1, from a lowermost fully opened position. A stop pin 67 joins the supports 36, 37 at the lower end and serves to limit the opening movement of the movable contact assembly. It is to be noted that the width of the striker contacts 65, 66 is greater than the space between each pair of fixed contact fingers when the switch is in the fully opened position. This structure provides for the upper portion of striker contacts 65, 66 to initially strike the fixed contacts at the lower ends, whereafter continued upward motion of the contact bridge 64 effects a wiping action between the fixed and movable contacts and a gradual spreading of the fixed contact finger pairs until at the termination of the closing action the lower end of the contact strikers 65, 66 are in contact with the upper ends of the elongated fixed contacts. Thus, initial contact is always made at the ends of the contacts which are wiped clean as the closing cycle is completed to thus minimize resistance even after repeated operations. Further, the final current path is through the base surfaces of the contacts, which surfaces are not subject to initial striking action. The operating mechanism 70 is mounted in a frame 71 which is bolted to the under side of the top casting 29. This operating mechanism 70 may be regarded as starting with the movable contact bars 60, 61 and including the upwardly extending insulating pull rod 72, the bottom end of which is connected to said movable contact member in a manner hereinafter described. Pivotally connected, at 73, to the top of the pull rod 72 is one of the two terminal pivot points of a rocker member or lever 74, which is shown, in its preferred form, as a triangular plate, of a generally channel section, with an end base portion 74a and a shortened rear leg portion 74b. The lever 74 may be disposed with its base line nearly horizontal, with two terminal pivot points 73 and 75 disposed near the ends of said base line, and having an upwardly extending apex portion which carries an intermediate rocker point 76, which is pivotally connected to a first end of a normally nearly horizontal link 77 which will be subsequently described. The second terminal pivot point 75 of the rocker member 74 is supported on the frame 71.

The link 77, which is pivoted at one end 76 to the top of the triangular rocker member 74 has a second end which is pivoted, at 78 to the inner end of an operating lever or drive lever 79. The outer end of the drive lever 79 is fixedly attached to a cam shaft 80 positioned perpendicularly to the operating lever 79' and mounted for rotation about its own axis through an aperture 81 in the lower portion of support bracket 82 bolted to the top casting 29 and extending through an apertured extension, not shown, of top casting 29. An operating handle 83 is fixedly attached at the inner end to one end of the cam shaft 80 by a pin 84. The outer end of the operating handle 83 normally presses up against a stop screw 30 which is carried by the underside of the top plate of the top casting 29.

The lower end of the pull rod 72 is attached to the previously described movable contact assembly by means of a resilient coupling operable to absorb impact energy when the movable contacts engage the fixed contacts during a switch closing operation and to urge the movable contacts into full engagement with the fixed contacts and to provide for a slight amount of over travel of the pull rod necessary to allow the mechanism to go over toggle as hereinafter described. Specifically, the resilient coupling assembly comprises a guide block 86 suspended between the support bars 69, 61 by means of a pair of opposed pins 87, 88 each connected on one side of the block to one of the bars 66, 61 at a point substantially midway along the longitudinal length of the bars 60, 61 between the pivot pin 62 and the spacer bracket 63. The block 86 is centrally apertured to slidably receive the lower end of pull rod 72 which extends downwardly through the block 86. A pair of opposing guide channels 89, 96 are provided on the guide block 86 for receiving a saddle bracket 91 having legs 92, 93 which slidably straddle the block, each leg riding in one of the guide channels 89, of the block 86. The lower end of pull rod 72 is connected to the legs 92, 93 of the slidable saddle bracket by means of a pin 94- through the legs 92, 93 and the pull rod 72 therebetween. A washer 95 surmounts the pin. A spring 96 is compressed between the washer 95 and the bottom of block 86. From the foregoing, it will be seen that the upward movement of pull rod 72 in a switch closing action will pivot the movable contact bars upwardly around pivot pin 62 causing the movable contact assembly to strike the fixed contact assembly, whereafter as the pull rod continues upwardly, forcing the movable contacts between the fixed contacts, the sliding bracket legs 91, 92 slide upwardly along block 86 to thus relieve the impact force and to cause compression of spring 96 between the pin 94 and the block 86 to urge the movable contacts upwardly into full final engagement bet-ween the fingers of the fixed contacts and to allow the pull rod 72 to come back down after the lever mechanism returns to the over toggle position, as shown in FIG. 1.

To provide for electrically operating the switch 17 so as to use it, for example, for controlling the connection of voltage regulating capacitors to a power system in response to changes in the voltage of the system, electroresponsive operating means 193 may be provided. The electro-responsive means 163 may, for example, comprise an electromagnet having an armature 104 pivotally connected to the drive lever 79 by a pin 105, and upper and lower operating windings 106 and 107, respectively. These windings may be disposed between plates 169, 110 and 111 of magnetic material, which plates may be maintained in spaced relation by bolts 112 which magnetically link the plates. The armature 194 is so disposed that when the upper winding 166 is energized, the armature will be pulled upwardly by magnetic flux in the gap between the upper plate 109 and the armature. It will be pulled downwardly by flux in the air gap between the lower plate 111 and the armature when the lower winding 167 is energized. This operates the handle 83 and drive lever 79 to open and close the switch.

A pair of snap acting limit switches 113, 114 are provided to cutoff energization of the trip coil 166 and the closing coil 107, respectively, at the end of the trip and the close operations. The limit switches 113 and 114 are fixedly mounted by any suitable means on opposite sides of the support bracket 82 previously described as supporting the operating shaft 80, operating handle 83 and operating lever 79. An insulator 115, 115 separates each limit switch from the bracket 82'. As shown in FIG. 3 particularly, the switches 113 and 114 are positioned so that their respective operating levers 116, 117 ride over a pair of corresponding cams 118, 119 respectively, on the cam shaft 80. FIG. 4 illustrates the relative positioning of the operating levers 116 and 117 and corresponding cams 118, 119 relating to FIG. 1 and FIG. 3 wherein the switch 17 is in the closed condition. In FIGS. 3 and 4, switch 113 is shown in the closed position while switch 114 is shown in the opened position. Alternatively, as the operating shaft 80 rotates from the position shown in a counterclockwise direction in response to an opening operation to be hereinafter described in detail, cams 118 and 119 rotate, switch 113 snaps open and switch 114 snaps closed at the end of the operation. The switch 113 is connected in the energizing circuit for the trip coil 106 while the switch 114 is connected in the energizing circuit of the closing coil 107 in a manner which will be obvious to those skilled in the art; accordingly, the conductors connecting the various elements in circuit have been omitted for the sake of drawing simplicity.

In the normal or closed position of the linkage, as shown in FIG. 1, the link 77 is in toggle lock with respect to the operating lever 79. In other words, the pivotal point 78 of this toggle linkage is slightly below the line joining the two terminal pivots 80 and 76 of the toggle, so that the weight or other opening bias of the movable contact assembly tends to rock the rocker member 74 in a counterclockwise direction about its second terminal pivot point 75, so that said rocker member presses the link 77 toward the operating lever 79' in such direction that most of the thrust is taken by the cam shaft 80 and support 82, but a small portion of said thrust is transmitted to the abutment 30 for the operating handle, in the normal closed position of the mechanism. The weight or other biasing force of the movable contact assembly is borne by the pivot 75, which is supported in the frame 41.

In operation, the movable bridge contact striker members 65, 66 are wedged between the corresponding finger contacts 53, 53 and 52, 52 respectively, deflecting the fingers to provide two parallel current paths through each finger pair to provide a magnetic attraction between the fingers to counteract blow open force encountered on high momentary inrush current.

An electrical tripping operation may be initiated by energizing the trip winding 106 through the closed limit switch 113 causing armature 104 to be driven upwardly and raising drive lever 79. This action initially releases the toggle arrangement of levers 79 and 77 and initiates counterclockwise rotation of cam shaft 80 to effect the previously described cam action with respect to limit switches 113 and 114. Thereafter, the continuous energization of trip coil 106 forces lever 79 upwardly, which in turn applies force through levers 77 and 74 to forcefully plunge the push rod 72 rapidly downward to break open the contact mechanism. At the same time, counterclockwise movement of cam shaft 80 effects a camming action on switches 113 and 114 so that as the contacts reach the fully opened position, the cams 118 and 119 reach the fully rotated position effecting a snap open operation of switch 113 to thus interrupt the energization of trip coil 106, and to simultaneously effect a closing operation of switch 114 to thus set up an operating circuit for the closing coil 107.

The switch 17 may be closed electrically by completing the energizing circuit for the operating winding 107 through closed switch 114. The armature 104 is thereupon pulled downwardly. Lever 79 is driven clockwise to effect clockwise rotation of lever 74 about pin 75. The pull rod is raised and bridging contact 64 is drawn into engagement with the stationary contacts. The toggle relation of levers 79 and 77 is restored, thus holding the switch 17 in the closed position. Cam shaft 80 is rotated clockwise to the position shown in the drawing, thus effecting a camming action to open switch 114 to deenergize the closing coil 107, and to close switch 113 to set up the trip circuit.

If desired, an electrical counter, not shown, may be connected in series with the closing coil to record the number of switch operations.

Having described a preferred embodiment of the invention, it is desired that the invention be not limited to the particular construction, but that various modifications and changes may be made without departing from the spirit and scope of this invention.

I claim as my invention:

1. Switch means, comprising: separable contact means; operating means for opening and closing said contact means; said operating means including an operating shaft rotatable about its central axis in a first direction in response to an opening operation, and in the reverse direction in response to a closing operation; a drive lever secured to said shaft to effect opening and closing of the contact means; cam means carried on said shaft and rotatable therewith; electro-responsive means energizable to be actuated in opposite directions to different positions and connected to operate the drive lever in opposite directions; limit switch means actuated by said cam means to deenergize the electro-responsive means at the end of each opening operation and at the end of each closing operation of the operating means, and manually operable means for also actuating the drive lever without disconnecting the electro-responsive means mechanically.

2. Switch means, comprising: fixed contact means; movable contact means movable into and out of engagement with said fixed contact means; operating means for effecting movement of the movable contact means into and out of engagement with the fixed contact means; said operating means including a pivoted drive lever operable from a first position to a second position to effect a contact opening operation of the operating means, and operable from said second position to said first position to effect a contact closing operation of the operating means; cam means driven by said drive lever; electroresponsive means connected to said drive lever and actuable in Opposite directions to selectively move the lever about its pivot for effecting operation of the operating means; means including limit switch means actuated by said cam means and responsive to the position of the drive lever in said first position and said second position to deenergize the electro-responsive means, and manually operable means for also actuating the drive lever about its pivot without disconnecting the electro-responsive means mechanically.

3. Switch means, comprising: fixed contact means; movable contact means operable to be moved into and out of engagement with the fixed contact means; a push rod connected to the movable contact means; lever means connected to said push rod and operable in opposite directions to actuate said push rod to effect opening and closing operation of the movable contacts; said lever means including a drive lever movable in opposite directions between predetermined limits to provide opening and closing driving forces to operate the lever mechanism; cam means driven by said drive lever; electroresponsive means connected to said drive lever and actuable in opposite directions to provide a driving force to selectively move said drive lever to effect contact opening and closing operation of the lever means; and auxiliary switch means actuated by said cam means and responsive to movement of the drive lever to said limits to deenergize the electro-responsive means.

4. Switch means, comprising: fixed contact means; movable contact means operable to be moved into and out of engagement with the fixed contact means; a push rod connected to the movable contact means; lever means connected to said push rod and operable to actuate said push rod to effect opening and closing operation of the movable contact means; said lever means including a drive lever pivoted for movement between two limits to provide opening and closing driving forces to operate the lever mechanisms; electro-responsive means connected to said drive lever and energizable to provide driving forces in opposite directions to selectively move said drive lever to effect contact opening and closing operation of the lever means; and cam means movable with said drive lever in opposite directions to deenergize the electro-responsive means upon completion of each operation of the lever means.

5. Switch means, comprising: fixed contact means;

movable contact means operable to be moved into and out of engagement with the fixed contact means; a push rod connected to the movable contact means; lever means connected to said push rod and operable to actuate said push rod to efiect opening and closing operation of the movable contacts; said lever means including a drive lever movable in opposite directions between two limits to provide opening and closing driving forces to operate the lever mechanisms; cam means driven by said drive lever; electro-responsive means connected to said drive lever and actua'ble in opposite directions to provide driving forces to selectively move said drive lever to effect contact opening and closing operations of the 8 lever means; and snap acting auxiliary switch means actuated by said cam means when the drive lever is at said limits to deenergize the electro-responsive means.

References Cited in the file of this patent UNITED STATES PATENTS 1,116,504 Simon Nov. 10, 1914 2,253,557 Collins Aug. 26, 1941 2,795,671 Edwards June 11, 1957 2,832,010 Chabala Apr. 22, 1958 2,867,736 Wiswell Jan. 6, 1959 2,870,288 Schmidt Jan. 20, 1959 2,961,510 Baird Nov. 22, 1960

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