US3248510A - Arcing horn and hinge mechanisms for disconnect switches - Google Patents

Description

April 26, 1966 G. R. M CLOUD ARCING HORN AND HINGE MECHANISMS FOR DISCONNECT SWITCHES 2 Sheets-Sheet 1 Filed Oct. 28, 1963 p Y, mm W Na e E m W 7 IPA. a 4

April 1966 G. R. M CLOUD 3,248,510

ARCING HORN AND HINGE MECHANISMS FOR DISCONNEGT SWITCHES Filed 001;. 28, 1963 2 Sheets-Sheet 2 41-rae/VEY United States Patent 3,248,510 ARCING HORN AND HINGE MECHANISMS FOR DISCONNECT SWITCHES George R. McCloud, South Milwaukee, Wis., assignor to McGraw-Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Oct. 28, 1963, Ser. No. 319,432 3 Claims. (Cl. 200162) The present invention relates to switches and more particularly to improved arcing horn latching and hinge structures for a high voltage disconnect switch.

In the disconnect switch of the present invention the applicant has provided a device that combines the use of the most economical commercially used highly conductive material, strip copper in an environment utilizing a minimum number of current interchanges. This is accomplished by using strip copper terminal members with a single strip of this material forming both the terminal pad and the blade contacting portion at both the pivot end and latch end of the blade assembly rather than using either built up terminal members having multiple current interchanges or using a one piece cast element composed of a material such as brass wherein the zinc content impairs the electrical conductivity. The use of round edge strip material for these switch elements also provides relatively high pressure single line electrical contact with the engaging blades without the necessity of additional machining or forming operations. In addition the arcing horn is disposed 'betwen the blades and is latched by engagement with a curved surface formed in the copper strip that serves as the contact at the latch end to provide not onl the latching function, but also for withdrawal of the arcing horn from the latch without engaging the terminal contact surface. The simple mechanical design of this switch minimizes the effects of heating and corrosion for the life of the switch and also provides an inherent capability to withstand momentary short circuit currents. With the blades disposed at either side of the contacting terminal members, the magnetic field caused by a fault current causes the blades to be drawn together and therefore during such a condition when a substantial magnetic field is established the contact pressure, and consequently the conductivity at the location of current interchange, is increased.

At the hinge end the hinge portion of the terminal is formed by pierce extruding the strip to avoid the necessity of a 90-degree bend and the additional current interchange required by the conventional hinge fabrication. A similarly forme-d strip used for the latch end terminal member also functions as a blade guide.

Also provided by the switch of the present invention is an arcing horn, quick break mechanism which is disposed between the switch blades to prevent accidental bending or damage. The latch associated with the arcing horn is incorporated into the copper strip stationary con tact and guide member and obviates any additional parts being required in associated with the terminal assembly.

It is an object of this invention to provide a disconnect switch having a minimum number of current exchanges while being made of the most highly conductive commercial materials.

It is a further object of this invention to provide a quick break mechanism or arcing horn utilizing the principal stationary contact member to provide the guiding and latching function.

It is also an object of this invention to provide a disconnect switch, that is economical to manufacture, of simple durable construction and reliable in use.

These and other objects and advantages of this invention will become apparent from the following description 3,243,519 Patented Apr. 26, 1966 when taken in connection with the accompanying drawings wherein:

FIG. 1 is a plan view of the disconnect switch embodying the present invention;

FIG.v 2 is a side elevation of the disconnect switch of FIG. 1 with the insulators and base partially broken away;

FIG. 3 is a partial vertical transverse section taken along line 33 of FIG. 2;

FIG. 4 is a side elevation of the switch blade and stationary contact terminal assemblies, partially in section and partially broken away, with a phantom view showing the switch blades partially disengaged; and

FIG. 5 is a partial side elevation of the switch of FIG. 1, showing the switch blades in a disconnected condition with the arcing horn still maintaining contact with the sta- The terminal assembly is secured at an intermediate location to the insulator 15 by bolts 19 that are threadably received by the bracket 21 carried by the insulator. At

one end the strip extends longitudinally and forms a terminal pad 23 which cooperates with the terminal 24 mounted thereon by bolts 25 and the opposite end 26 extends upwardly and is pierced extruded to receive and retain the cylindrical shank of a'bolt 27 in closely contacting relation therewith. A reinforcing bar 29 extends from a riveted connection with the upwardly extending strip end 26 to a sloted opening 31 in the strip where it is re tained in fixed'relation by having the shoulder surfaces 33 abut one side and the turned tab 35 engage the opposite side.

The latch end terminal assembly 37 has a single strip of round edge copper material formed to provide both a terminal pad 38 and a stationary contact 39. The strip copper material referred to as round edge is strip material commonly formed by rolling round rods into strip material which yields a strip having a curved edge of nominally round configuration which is free of sharp edges. The assembly 37 is secured to bracket 40 carried by the insulator 14 by the bolts 41 and a terminal 43 cooperates with the terminal pad 38 on which it is mounted by bolts 44. The stationary contact 39 (also shown in FIG. 3) provides parallel transverse edge surfaces 46 with a terminal portion 47 wherein the transverse edge surfaces converge to form a blade guide. Also incorporated in the stationary contact 39 along one transverse edge is a depression or groove 49 formed by a curved reentrance surface that acts as a latching surface for the arcing horn 50 of the quick break mechanism which will be described hereafter. The stationary contact 39 also carries a keeper 52 that is riveted thereto. A pair of hard drawn copper switch blades 55, 56 are maintained in horizontal spaced relation intermediate the ends thereof by a sleeve '58 which extends between the blades abutting the confronting blade surfaces and a pin 59 extending through the sleeve and the blades to firmly secure the switch blades against the axial ends of the sleeve.

At the latch end a pin 61 extends through openings in the blades 55, 56 and a spacing sleeve 62. The spacing sleeve 62 is slightly shorter in its axial direction than the distance between transverse edges 46 of the stationary contact 39 and the pin is of sufficient length to provide a space between the head 63 of the pin 61 and the adjoining surface of blade 55. A compression spring 60 disposed about the pin 61 applies a biasing force between the head of the pin and the switch blade to urge the blades toward one another into contact with the axial ends of sleeve 62 when the switch is pivoted to a disconnected position and into intimate wiping contact with the transverse edges 46 of stationary contact 39 when the switch is in a closed condition with the stationary contact disposed between the blades 55, 56. At the hinge end of the switch the bolt 27 extends through the switch blades 55, 56 and is retained as previously stated by passing through the pierce extruded openings in the upwardly extending end 26 of the terminal assembly strip portion 17. The nut 65 and jamb nut 66 hold the blades 55, 56 against the transverse edges of the strip 18 with spring washers 67 affording a biasing means to maintain compressive wiping contact between the blades 55, 56 and the round edge surfaces of the copper strip end portion 26 of the hinge end terminal assembly.

As seen also in FIG. 4, a latch lever 69 is mounted between the switch blades 55, 56 and secured thereto by trunnions 71 formed integrally therewith which are received in co-axial blade openings. The latch lever 69 has a depending hook 70 that cooperates with the lower latching surface 72 of the keeper to provide positive latching engagement when the switch is closed, an arm portion 73 having a curved pry out surface that overlies a cooperating upper pry out surface of the keeper when the switch is closed and a nose portion 74 that extends toward and is engageable by a portion of the control lever 75. The control lever is likewise pivotally mounted on the switch blade assembly by trunnions 77 (FIG. 1), formed integrally therewith, that are received in co-axial blade openings. One arm of the control lever terminates in a pull ring 78 while the arm 79 engages the latch lever nose portion 74 to cause the latch lever 69 and the control lever 75 to rotate in opposite directions upon activation of the control lever by a pull-on ring 75. A torsion spring 81 coiled about the latch lever with one end turned about the switch blade 56 and the other about the latch lever nose portion 74 biases the latch lever 69 toward latching engagement with the keeper 52. As seen in FIG. 4, the pivotal movement of the control lever is limited in a clockwise direction by engagement between shoulder 82 and sleeve 58 and in a counterclockwise direction by engagement between the depending portion 83 and the latch lever 69.

Mounted between the blades and carried thereby is a resilient arcing horn 50 having a coiled portion 85 to increase its resiliency. A tab 87 which is bolted to the switch blade 55 secures the arcing horn to the blade with positive positioning afforded by an end portion which extends beyond the tab 87 and is turned at a right angle and projects into an opening in the blade 55. The areing horn is biased toward the blade 55 and the stationary contact engaging distal portion 88' is retained in a leading relation to the blade 55 as the latter is pivoted toward a closed position by a bracket 89 riveted to the blade which has a trough-like retaining surface and a depending guide surface for directing the blade into the trough.

In operation, as the switch is closed, the arcing horn 50 is displaced transversely along the shoulder of the guide bracket 89 by contact with the guiding edge surface of the stationary contact 39. The blades 55, 56 are thereafter displaced against the force of the biasing spring 60 by the transverse guide and contact surfaces of the stationary contact 39 followed by a displacement of hook member 70 of latch lever 69 against the biasing force of spring 81 as the hook engages the striker surface of the keeper 52. As the hook approaches a latched position in underlying relation to the keeper-latching surface 72, the arcing horn distal end portion 88 enters the latching recess or groove 49 in the stationary contact followed by the 4 positive latching engagement between the keeper 52 and the hook 70.

Referring to FIGS. 4 and 5, when the switch is opened a force is applied which is representatively shown by the arrow A overlying the pull ring of FIG. 5 which causes the control lever to pivot in a clockwise direction and the latch lever to pivot in a counterclockwise direction from the full line position to the dotted line position as shown in FIG. 4. The initial pivoting of the control lever causes the latch lever to be pivoted to a position wherein the hook portion 70 no longer underlies the latching surface 72 of the keeper and thereafter the pry-out surface of the latch lever arms 73 engages the pry-out surface of the keeper 52 to provide a positive prying force urging the switch blades from engagement with the stationary contact 39 to overcome any force that may inhibit the opening of the switch such as a severe icing condition. When the switch blades 55, 56 have been pivoted in a clockwise direction away from engagement with stationary contact 39 as illustrated in FIG. 5, the arcing horn 50 will still remain in contact with the arcing horn latch portion 49 of the stationary contact until the switch blades have been sufficiently pivoted to draw the arcing horn wire clear of the latching engagement with groove 49. At that time the resilience of the arcing horn and the coiled portion will cause the arcing horn to be quickly returned to a normal position of contact with the recess surface of the support bracket 89.

Although but one embodiment has been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A disconnect switch comprising a blade member having a latch end and a hinge end and being pivotable between open and closed positions; an arcing horn secured to said blade member and extending adjacent said blade member toward said latch end with the distal end thereof disposed in leading relation to said blade as said blade is pivoted toward said closed position; a first terminal member having said blade member pivotally mounted thereon adjacent said hinge end; a second terminal member including a piece of strip material presenting a blade guiding surface and a blade contacting transverse edge surface, said guiding surface and said contacting edge surface serving as an arcing horn guiding surface; and arcing horn latch means comprising a concave surface extending into the strip material of said second terminal member from said blade contacting edge surface, said areing horn being oriented to be withdrawn from said latch means without engaging said contacting surface when blade member is pivoted away from said closed position.

2. A disconect switch comprising a blade assembly including a pair of generally parallel switch blades interconnected for unitary pivotal movement about a transverse axis between a first open position and a second closed position; an arcing horn secured to said assembly; a first terminal member hingedly connected to said blade assembly about said transverse axis adjacent one end of said assembly; a second terminal member including a single piece of highly conductive round edge strip material with a terminal pad portion and an upright contact portion, said upright portion extending between said blades with transversely disposed parallel round edge portions thereof in contacting relation with the confronting major surfaces and said blades when said assembly is in said second position and presenting blade guide surfaces that incline toward and merge into said blade contacting round edge surfaces; and an arcing horn retaining latch means comprising a concave surface extending into said second terminal strip material from one of said parallel round edge surfaces, said latch means and arcing horn being positioned to prevent contact between said arcing horn and said blade Contacting surfaces when said assembly is pivoted from said second position to said first position and said arcing horn is withdrawn from contact with said second terminal member.

3. A disconnect switch comprising a blade assembly having a first closed position and a second open position, said assembly having a pair of substantially parallel blades interconnected for unitary pivotal movement about a transverse axis; a resilient arcing horn secured to said assembly intermediate said blades in leading relation to said assembly when said assembly is being pivoted toward said first position; a fixed hinge member including a single piece of highly conductive round edge strip material having a first terminal pad portion and a second switch blade engaging portion extending between said blades with the round edge portions thereof abutting said blades, said blade assembly and said hinge member second portion being longitudinally pierced intermediate said blades with strips formed thereby alternately bent to radially retain a pin extending therethrough and carried by said blade assembly; a fixed contact member including a single piece of round edge strip material with a third terminal pad portion and a fourth upright contact portion, said fourth portion extending between said blades with transversely disposed round edge surfaces engaging the confronting major surfaces of said blades when said assembly is in said first position; and arcing horn latch means formed by a concave surface extending transversely into said fourth portion from one of said round edge surfaces.

References Cited by the Examiner UNITED STATES PATENTS 504,528 9/ 1893 Herrick 200-62 2,317,118 4/ 1943 Schultz et al. 200-62 2,803,726 8/1957 Gilliland 200-48 X KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

WILLIAM C. GARVERT, Assistant Examiner.

Claims (1)

1. A DISCONNECT SWITCH COMPRISING A BLADE MEMBER HAVING A LATCH END AND A HINGE END AND BEING PIVOTABLE BETWEEN OPEN AND CLOSED POSITION; AN ARCING HORN SECURED TO SAID BLADE MEMBER AND EXTENDING ADJACENT SAID BLADE MEMBER TOWARD SAID LATCH END WITH THE DISTAL AS SAID THEREOF DISPOSED IN LEADING RELATION TO SAID BLADE AS SAID BLADE IS PIVOTED TOWARD SAID CLOSED POSITION; A FIRST TERMINAL MEMBER HAVING SAID BLADE MEMBER PIVOTALLY MOUNTED THEREON ADJACENT SAID HINGE END; A SECOND TERMINAL MEMBER INCLUDING A PIECE OF STRIP MATERIAL PRESENTING A BLADE GUIDING SURFACE AND A BLADE CONTACTING TRANSVERSE EDGE SURFACE, SAID GUIDING SURFACE AND SAID CONTACTING EDGE SURFACE SEVING AS AN ARCING HORN GUIDING; SURFACE AND ARCING HORN LATCH MEANS COMPRISING A CONCAVE SURFACE EXTENDING INTO THE STRIP MATERIAL OF SAID SECOND TERMINAL

Images