US3235696A

US3235696A - Load break disconnecting device with solid nonconducting arc suppression means

Info

Publication number: US3235696A
Application number: US298882A
Authority: US
Inventors: Harvey W Mikulecky
Original assignee: McGraw Edison Co
Current assignee: McGraw Edison Co
Priority date: 1963-07-31
Filing date: 1963-07-31
Publication date: 1966-02-15
Anticipated expiration: 1983-02-15

Description

1966 H. w. MIKULECKY 3 235,696

9 LOAD BREAK DISCONNECTING DEVICE WITH SOLID NONCONDUGTING ARC SUPPRESSION MEANS Filed July 31, 1963 3 Sheets-Sheet 1 INVENTOR HARVEY w. MIKULECKY AT TORNEY Feb. 15, 1966 H. w. MIKULECKY LOAD BREAK DISCONNECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSION MEANS 3 Sheets-Sheet 2 Filed July 31, 1963 85 52M Luna/W2C 85 ATTORNEY Feb. 15, 1966 H. w. MIKULECKY 3,235,696

LOAD BREAK DISCONNECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSION MEANS 5 Sheets-Sheet 5 Filed July 51, 1963 6 INVENTOR o HARVEY W.MIKULECKY AT TORN EY United States Patent 3,235 696 LQAD BREAK DISCONNIECTING DEVICE WITH SOLID NONCONDUCTING ARC SUPPRESSION MEANS Harvey W. Mikulecky, Racine, Wis, assignor to McGraw- Edison Company, Milwaukee, Wis, a corporation of Delaware Filed July 31, 1963, Ser. No. 298,882 14 Claims. (Cl. 206-449) This invention relates to load break disconnecting switches which have particular, but not exclusive, application for use with housed, ground-level mounted transformers employed with underground distribution systems.

For reasons of aesthetics as well as safety and sys tem longevity, buried electrical distribution systems are widely employed. Step down distribution transformers employed in such distribution systems must be accessible, however, so that they are generally mounted on a ground-level concrete pad and are enclosed within a metallic housing. It is preferable that these housings be as compact as possible, not only so they will be inconspicuous, but also for reasons of economy and safety. As a result, conventional load break disconnecting switches and fuses, which are designed for use in installations where space is not a particular problem, have been found unsatisfactory for use with underground systems.

It is a primary object of the invention to provide a load break interrupting device which is both economical and sufficiently compact for use within the housings of ground-level mounted transformers and which has sufficient interrupting capacity without being immersed in a dielectric liquid.

Another object of the invention is to provide a load interrupting device which may be operated with ordinary linemans tools.

Yet another object of the invention is to provide a load interrupting device having arc extinguishing means which moves the are off of the main current carrying contact portions prior to the interruption thereof.

A more specific object of the invention is to provide a load break disconnecting device wherein nonconductive means is mounted on an elongate switch means and is resiliently urged into covering relation of a conductive portion of the switch means relative to stationary contact means upon movement of the switch means away from the stationary contact means so that any arc struck therebetween will be extinguished. A still more specific object is to provide such a load break disconnecting device wherein the nonconductive means is a sleeve concentrically mounted on the switch means for longitudinal movement toward a covering relation with respect to the conductive portion. Another specific object of the invention is to provide such a load break disconnecting device wherein the switch means includes spring latch means for holding the nonconductive means away from the conductive portion and wherein the stationary contact means includes latch release means so that the nonconductive means is released upon movement of the switch means into and subsequently out of engagement with the stationary contact means.

A further object of the invention is to provide a load interrupting device which cannot be closed until its interrupting structure is relatched wherein no complicated interlocking linkages are required.

These and other objects and advantages of the instant invention will become more apparent from the detailed description thereof taken with the accompanying drawings wherein: I

3,235,696 Patented Feb. 15, 1966 FIG. 1 shows a transformer enclosure in which the load break disconnecting switch according to the instant invention is useable;

FIG. 2 schematically illustrates the transformer enclosure shown in FIG. 1;

FIG. 3 is a side elevational view, with parts broken away, of one type of load break interrupting switches according to the instant invention;

FIG. 4 is a view taken along lines 44 of FIG. 3;

FIG. 5 is a side elevational view, with parts broken away, of the device shown in FIG. 3 wherein the arc interrupting mechanism is shown in greater detail;

FIG. 6 is a view taken along lines 66 of FIG. 5; and

FIG. 7 is a side elevational view, partly in section, of another type of break interrupting devices according to the instant invention.

Referring now to the drawings in greater detail, FIGS. 1 and 2 show a metallic enclosure 11 for housing a ground-level transformer 11 and which is mounted on a concrete pad 12. The enclosure 10 is provided with an access door 13 for exposing a terminal bushing compartment 14 and a load break interrupting switch compartment 15 which are separated from each other by a panel 16 and from the transformer compartment by an inner panel 17. As will be understood by those skilled in the art, the various panels members forming the

compartments

14 and 15 may be composed of insulating material if the electrical clearance distance between them and electrically live parts is insufficient for the voltages being carried.

The terminal compartment 14 is shown in FIGS. 1 and 2 to include a first terminal 20 which is mounted on and insulated from the panel 17 by an insulator 21 and which connects one side of the transformer secondary winding 22 to a load conductor 24 extending downwardly through an aperture 26 in the lower end of the compartment 14 and to the underground distribution system. The compartment 14 also includes a ground terminal 25 affixed to the panel 17 for connecting the other side of the secondary winding 22 to a ground conductor 27 extending downwardly through the aperture 26 to the underground system.

The compartment 15 is shown in FIGS. 1 and 2 to enclose three

load break switches

30, 32 and 34 which are disposed in parallel side-by-side relation. Each of the

load break devices

30, 32 and 34 includes an

elongate switch portion

35, 37 and 39, respectively, each of which is pivotally mounted at its lower end for movement into and out of engagement with a stationary contact assembly 40. The stationary contact assembly 40 includes a

stationary contact jaw

42, 44 and 45 for each of the

disconnect switches

30, 32 and 34, respectively, and each is mounted on and electrically connected to a common bus support 47 which is supported on insulators 48 secured to the panel 17.

Insulating panels

50 and 52 separate the central load break switch 32, whose conductive portion 37 includes a fuse, from the outer load break switches 30 and 34 whose

conductive portions

35 and 39, respectively, comprise switch blades. As seen in FIG. 2, one side of the transformer high voltage winding 55 is connected to fuse 37 and its other side is grounded. The

switch blades

35 and 39 are respectively connected to

conductors

57 and 58 which are connected to a loop energizing circuit which is not shown but which is understood by those skilled in the art to consist of a power distribution system wherein an energy source is disposed at each end of the system and power may flow in either direction. It can be seen, therefore, from FIG. 2, that by opening the load break switch 32 the'transformer 11 may be'isolated from the loop circuit or by opening the load break switches 30 or 34 the transformer 11 may be isolated from power flow in either direction.

The switch portion 35 of disconnect switch 39, which is identical to the switch portion 39 of disconnect switch 34, is shown in FIGS. and 6 to comprise a hollow tubular switch blade of any suitable highly conductive material, such as copper. A hinge and contact member 60 is carried at the lower end of switch blade -35and includes a pair of hinge lugs 62 extending laterally its opposite sides and a pair of contact fingers 63 extending from one of its ends.

A generally U-shaped hinge member 65 is provided for cooperation with the member 60 and is afiixed by means of a bolt 66 to an insulator 68 which is mounted on the panel 17 and which supports the member 65 in substantial vertical alignment below the stationary contact assembly 42. Each of the arms of the hinge member 65 have an arcuate cam slot 76 for receiving the hinge lugs 62 so that when the switch blade 35 is rotated into its closed position as shown by full lines in FIG. 3, the contact fingers 63 are forced into high pressure engagement with an inverted U-shaped resilient contact member 72 which is also secured to the insulator 68 and which is held in high pressure engagement with a flat terminal bar '73 by the bolt 66.

The bus member 47 is shown in FIG. 3 to be generally L-shaped in cross-section and to carry an elongate bumper member 76 on its edge facing the pivotal switch blade 35. The purpose of the bumper member '76 which may be composed of rubber or the like, will be explained in greater detail hereinbelow in connection with the interrupting structure according to the instant invention.

As seen in FIG. 4, the stationary contact assembly 42 includes a resilient U-shaped conductive member 78 which is affixed to the bus bar 47 by a bolt 79 and which provides a pair of opposed contact fingers 80, each of which has an outwardly flared end portion 82 for guiding the contact rod 35 into its engaged position. Each of the ends 82 of the contact fingers 80 has a longitudinal embossment 84 extending along its length so that the contact rod 35 will snap into position against the bumper 76 upon movement toward its closed position. A U-shaped back-up spring member 85 is disposed adjacent the contact member 78 to provide the requisite contact pressure and is held in position by the bolt 79.

The arc interrupting assembly according to the instant invention is carried adjacent the upper end of the contact rod 35 and includes a nonconductive plug 90 affixed to the extreme upper end of the contact rod 35 and a nonconductive sleeve 92 which is slideably mounted in a surrounding relation on the upper portion of the contact rod 35 and is resiliently urged toward plug 90. Each of the

nonconductive members

90 and 92 consists of a material having good are extinguishing properties, such as Rosite 3250A and 32500, fiber, nylon, or Teflon. Another favorable property exhibited by thhese materials is that they are nontracking, i.e., potentially conductive material such as carbon does not deposit readily on their surfaces.

More specifically, the plug 90 is slightly tapered and from its upper to its lower end its outer diameter is substantially the same as that of the tube 35 while its lower end 93 is of reduced diameter for insertion into the upper end of the conductive tube 35 so that there is no sharp discontinuity between the surfaces of the tube 35 and the plug 90. A stop flange 94 is integrally formed at the upper end of the plug 90. As seen in FIGS. 3 and 4, when the switch blade 35 is in its closed position the contact fingers 80 engage the tube 35 at a point immediately below its juncture with the nonconducting plug 90.

In order that the disconnect switch 30 may be operated between its connected and disconnected positions by means of a hook stick or other similar tool, an eye 96 is secured to the plug 90 by means of an integral stem 97 embedded within and completely surrounded by the plug 4 so that the eye 96 is electrically insulated from the tube 35.

The nonconductive sleeve 92 is telescopically received over the conductive tube 35 and has an annular closure portion 100 extending integrally inward from its upper end. A cylindrical re-entrance portion 102 extends back into the sleeve 92 from the inner edge of closure portion 100 and has an inner cylindrical surface 103 which closely surrounds tube 35 to provide a bearing for the telescopic sliding engagement between thhe sleeve 92 and the tube 35. A compression spring 106, which is disposed in surrounding relation to the tube 35 and within the member 92, ext-ends between the closure portion 100 of the tube 92 and a washer 107 surrounding the tube 35 and supported against downward movement by a transverse pin 109 extending through the tube 35. It can be seen therefore that the spring 106 urges the sleeve member 92 upwardly of the rod 35 and toward the nonconductive plug 90 but that this movement is normally prevented by a latch spring 110 having a generally U-shaped body portion 112 disposed within the tube 35 and a latch tip 114 extending radially outwardly therefrom through a longitudinal slot 115 formed adjacent the upper end of the tube 35.

When the tubular member 92 has been latched and prior to engagement between the conductive rod 35 and the stationary contacts 42, the sleeve 92 and the latch spring 119 are in their position shown by full lines in FIG. 5. As the switch blade 35 is pivoted toward engagement with the stationary contacts 42 and as the tube 35 snaps past the embossments 84 on the contact fingers 80, the bumper 76 will engage the latch tip 114 of the spring 110 forcing said latch tip into the interior of the tube 35. This allows the tubular member 92 to move upwardly a slight distance until it engages the bumper 76 as seen by phantom lines in FIG. 5. The re-entrance surface 102 thus moves over the lower edge of the latch tip 114 so that upon subsequent movement of the contact rod 35 out of engagement with the bumper 76, the latch tip 114 will be prevented from relatching the nonconductive sleeve 92.

When the load break switch 30 is in its closed position, current flow therethrough is from the conductor 57 to the terminal member 73, the spring contact '72, the contact fingers 63, tubular member 35, the contact fingers 80 and the bus bar 47.

When it is desired to interrupt load current a suitable tool is engaged with the eye 96 and the tube 35 is rotated in a clockwise direction as viewed in FIG. 3. As the tube 35 moves out of engagement with the bumper 76, sleeve member 92 will be moved upwardly by the spring 106 until its upper closure portion engages the lower edge of the contact fingers 80 as seen by phantom lines in FIG. 3. Further clockwise movement of the tube 35 will disengage its upper end from the embossed portions 84 of the contact fingers 80 whereupon an arc will be struck therebetween. Continued pivotal movement will then disengage the sleeve 92 from the lower edge of the contact fingers 80 whereupon it will be snapped upwardly by the spring 106 until its upper closure portion 100 engages the flange 94 also as shown by phantom lines in FIG. 3. As the sleeve 92 moves upwardly on the tube 35, the arc existing between the contact fingers 84 and the upper end of said rod 35 will be confined to a continually decreasing portion of the rod until it is extinguished as the upper end of the sleeve 92 moves onto the nonconductive plug 90. This insures that the arc is forced 01f of the main contact area of the rod 35 so that there is a minimum of burn damage to the main areas of contact of both the rod 35 and the. contact fingers 84. In addition because the plug 90 is. tapered from its lower to its upper end there is substan-- tially zero tolerance between the surface 103 and the: upper end of the plug 90 so that there is no gap between these members through which the arc can continue.

Resetting of the interrupting sleeve 92 is accomplished by physically moving said sleeve downwardly on the rod 35 until its upper closure portion 100 moves below the latch tip 114 of spring latch 110 whereupon said latch tip will snap outwardly through slot 115 to hold sleeve 92 against movement toward plug 90 under the influence of spring 106. It will be appreciated that if an attempt is made to move the tube 35 into its closed position without first resetting the interrupting sleeve 92, the latter will engage the contact fingers 80 and because its diameter is substantially greater than that of tube 35 it cannot be forced between said contact fingers and accordingly movement of the switch 30 into a closed position is prevented. Further, because the upper end of the rod 35 will be completely enclosed, prior to the latching of the sleeve 92, electrical engagement between said contact rod and the contact fingers 80 will be impossible. Thus sleeve 92 prevents closure of the switch 30 without first resetting the same, and this is accomplished without complicated interlocking structure.

As seen in FIG. 7, the disconnecting fuse 32 is identical with the disconnect switch 30 except that in the fuse 32 a fuse 120 replaces the lower end of the contact tube 35. This fuse may be of any conventional well known type and may include, for example, a fusible element 121 wound around a support rod 122 of an insulating material such as fiber glass impregnated with resin. Element 121 is electrically connected at its ends to conductive

tubular member

123 and 124 respectively carried at the upper and lower ends of the rod 122. A protective tube 125 of insulating material, such as fiber, is aflixed to the

conductive members

123 and 124 adjacent the ends of rod 122 by suitable washers 126 and cement 127.

The load break disconnecting switches just described provides simplicity, economy and a relatively high interrupting capability suitable for the interrupting of load or transformer energizing currents. The use of the device with a ground level housed transformer is particularly advantageous because it requires a minimum of space and provides a visible air gap for safety.

While the interrupting device according to the instant invention has been shown with respect to one type of disconnecting switch or fuse and while it has been shown with respect to a housed transformer, it is not intended that the invention be limited thereby but only by the scope of the appended claims.

I claim:

1. A load break disconnecting device comprising stationary contact means, elongate switch means having a conductive portion and being mounted for movement of said conductive portion into and out of engagement with said stationary contact means, nonconductive means mounted on said elongate switch means and movable relative thereto into and out of covering relation of said conductive portion relative to said stationary contact means, means resiliently urging said nonconductive means toward said covering relation, first means for holding said nonconductive means out of said covering relation when said switch means is out of engagement with said stationary contact means, second means associated with said stationary contact means and being operable to release said nonconductive means from said first means and prevent movement of said nonconductive means into said covering relation when said conductive portion is in engagement therewith, movement of said elongate switch means out of engagement with said stationary contact means being operable to release said nonconductive means for movement into said covering relation whereby any are struck between said stationary contact means and said conductive portion will be extinguished.

2. A load break disconnecting device comprising stationary contact means, elongate switch means having a conductive portion and being mounted for movement of said conductive portion into and out of engagement with said stationary contact means, nonconductive means mounted on said elongate switch means for movement into and out of covering relation of said conductive portion relative to said stationary contact means, means resiliently urging said nonconductive means toward said covering relation, means for holding said nonconductive means away from said conductive portion, and release means actuable when said elongate switch means is moved into its closed position to release said nonconductive means toward said covering relation and into engagement with said stationary contact means, movement of said switch means out of engagement with said stationary contact means being operable to release said nonconductive means for movement into said covering relation whereby any are struck between said stationary contact means and said portion will be extinguished.

3. A load break disconnecting device comprising stationary contact means, elongate switch means having a conductive portion and being pivotally mounted at one end for movement of said conductive portion into and out of engagement with said stationary contact means, nonconductive means mounted on said elongate switch means for movement into and out of surrounding relation to said conductive portion, means resiliently urging said nonconductive means toward said conductive portion, latch means for holding said nonconductive means awa from said conductive portion, and latch release means actuable when said elongate switch means is moved into its closed position to release said latch and allow said resilient means to urge said nonconductive means toward said conductive portion and into engagement with said stationary contact means, movement of said switch means out of engagement with said stationary contact means being operable to release said nonconductive means for movement onto said conductive portion whereby any are struck between said stationary contact means and said portion will be extinguished.

4. A disconnecting device comprising first and second spaced apart terminal means, stationary contact means mounted on one of said terminal means, elongate switch means having a conductive portion adjacent one end thereof and being mounted at its other end on the other of said terminal means for movement of said conductive portion into and out of engagement with said stationary contact means, sleeve means disposed in surrounding relation to a portion of said elongate conductive means and being composed of a nonconductive material, means resiliently urging said nonconductive sleeve means toward the one end of said switch means to cover the conductive portion thereof, latch means for holding said nonconductive sleeve means away from said conductive portion, and latch release means actuable when said elongate switch means is moved into its closed position to release said latch and allow said resilient means to urge said nonconductive sleeve means toward said nonconductive portion and into engagement with said stationary contact means, movement of said switch means out of engage ment with said stationary contact means being operable to release said nonconductive sleeve means for movement onto said conductive portion whereby any are struck between said stationary contact means and said conductive portion will be extinguished.

s. A disconnecting device comprising first and second spaced apart terminal means, stationary contact means mounted on one of said terminal means, elongate switch means having a conductive portion and being pivotally mounted at one end on the other of said terminal means for movement of said conductive portion into and out of engagement with said stationary contact means, said switch means also including a nonconductive portion adjacent the free end thereof, nonconductive sleeve means disposed in surrounding relation to a portion of said elongate switch means, means resiliently urging said nonconductive sleeve means toward said nonconductive portion to cover the conductive portion of said switch means,

latch means for holding said nonconductive sleeve means away from said nonconductive portion, and latch release meansmounted on said one terminal means and engageable with said latch means to release said latch and allow said resilient means to urge said nonconductive sleeve means toward said nonconductive portion and into engagement with said stationary contact means when said elongate switch means is moved into its closed position, movement of said conductive portion out of engagement with said stationary contact means being operable to release said nonconductive sleeve means for movement onto said conductive portion whereby any arc struck between said stationary contact means and said conductive portion will be extinguished.

6. A load break disconnecting device comprising first and second spaced apart terminal means, a pair of pposed contact fingers mounted on one of said terminal means, elongate switch means having a conductive portion adjacent one end and being pivotally mounted adjacent its other end on the other of said terminal means for movement of said conductive portion into and out of engagement between said contact fingers, said conductive portion being electrically connected to said other terminal, nonconductive sleeve means disposed in surrounding relation to a substantial portion of said elongate switch means and being mounted for sliding movement longitudinally therealong, spring means disposed within said sleeve means for resiliently urging said sleeve means toward said conductive portion, said switch means having an aperture formed therein adjacent said conductive portion, spring latch means disposed within said switch means and having a latch tip extending through said aperture to prevent movement of said sleeve means toward said conductive portion, bumper means mounted on said one terminal means and engageable with said latch tip when said elongate switch means is moved into its closed position to force the latter into said switch means and release said sleeve means for movement toward said conductive portion and into engagement with said contact fingers, movement of said conductive portion out of engagement with said contact fingers being operable to release said nonconductive sleeve means for movement onto said conductive portion whereby any are struck between said stationary contact means and said conductive portion will be extinguished, the width of said sleeve means being substantially greater than that of said conductive portion so that engagement of said switch means between said contact fingers is prevented until said sleeve means has been relatched.

7. A load break disconnecting device comprising stationary contact means, elongate switch means having a conductive portion adjacent one end and being pivotally mounted adjacent its other end for movement of said conductive portion into and out of engagement with said stationary contact means, nonconductive sleeve means disposed in surrounding relation to a substantial portion of said elongate switch means and being mounted for sliding movement longitudinally therealong, spring means for resiliently urging said sleeve means toward said conductive portion, said switch means having an aperture formed therein adjacent said conductive portion, spring latch means disposed within said switch means and having a latch tip extending through said aperture to prevent movement of said sleeve means toward said conductive portion, latch release means mounted adjacent said stationary contact means and operable when said elongate switch means is moved into its closed position to force said latch tip into said switch means and release said sleeve means for movement toward said conductive portion and into engagement with said stationary contact means, movement of said conductive portion out of engagement with said stationary contact means being operable to release said nonconductive sleeve means for movement onto said conductive portion whereby any are struck between said stationary contact means and said 8 conductive portion will be extinguished, the width of said sleeve means being substantially greater than that of said conductive portion so that engagement of said switch means and said stationary contact means is prevented until said sleeve means has been relatched.

8. A load break disconnecting device comprising first and second spaced apart terminal means, a pair of opposed contact fingers mounted on one of said terminal means, elongate switch means having a conductive por tion adjacent one end and being pivotally mounted adjacent its other end on the other of said terminal means for movement of said conductive portion into and out of engagement between said contact fingers, said conductive portion being electrically connected to said other termi' nal, said switch means also including a nonconductive portion adjacent the free end thereof, nonconductive sleeve means disposed in surrounding relation to a substantial portion of said elongate conductive means and being mounted for sliding movement longitudinally therealong, spring means disposed within said sleeve means for resiliently urging said sleeve means toward said nonconductive portion to cover the conductive portion of said switch means, said switch means having an aperture formed therein adjacent said conductive portion, spring latch means disposed within said switch means and having a latch tip extending through said aperture to prevent movement of said sleeve means toward said nonconductive portion, bumper means mounted on said one terminal means and engageable with said latch tip when said elon gate switch means is moved into its closed position to force the latter into said switch means and release said sleeve means for movement toward said nonconductive portion and into engagement with said contact fingers, embossment means formed on each of said contact fingers so that said latch tip will be moved into positive engagement with said bumper means, movement of said conductive portion out of engagement with said contact fingers being operable to release said nonconductive sleeve means for movement onto said conductive and nonconductive por tions whereby any are struck between said stationary contact means and said conductive portion will be extin guished, the width of said sleeve means being substantially greater than that of said conductive portion so that en gagement of said switch means between said contact fingers is prevented until said sleeve means has been re latched.

9. The load break disconnecting device set forth in claim 8 wherein said elongate switch means comprises a switch blade.

10. The load break disconnecting device set forth in claim 8 wherein said elongate switch means includes an elongate fuse and wherein said conductive portion thereof comprises a rod-like member extending axially from said fuse and being electrically connected thereto.

11. A disconnecting device comprising first and second spaced apart terminal means, stationary contact means mounted on one of said terminal means, elongate switch means having a substantially cylindrical conductive portion and being pivotally mounted at one end on the other of said terminal means for movement of said conductive portion into and out of engagement with said stationary contact means, said switch means also including a plug portion disposed adjacent the conductive portion and being tapered outwardly therefrom, sleeve means having a central opening disposed in concentric surrounding relation to said elongate switch means, said sleeve means and the plug portion of said switch means being a nonconductive nontracking material, resilient means urging said sleeve means toward said plug portion to cover the conductive portion of said switch means, latch means for holding said sleeve means away from said plug portion, and latch release means mounted on said one terminal means and engageable with said latch means to release said latch means and allow said resilient means to urge said sleeve means toward said plug portion and into engagement with said stationary contact means when said elongate switch means is moved into its closed position, movement of said conductive portion out of engagement with said stationary contact means being operable to release said sleeve means for movement onto said plug portion whereby any are struck betwen said stationary contact means and said conductive portion will be extinguished, the diameter of the opening in said sleeve means being substantially equal to that of the plug portion at the largest point thereof so that there is a minimum clearance therebetween for continuation of said arc.

12. A load break disconnecting device comprising first contact means, second contact means having a conductive portion and being mounted for movement of said conductive portion into and out of engagement with said first contact means, nonconductive means mounted on said second contact means for movement relative thereto into and out of covering relation of said conductive portion relative to said first contact means, means resiliently urging said nonconductive means toward said covering relation, means for holding said nonconductive means away from said conductive portion when said second contact means is out of engagement with said first contact means, said first contact means including means engageable by said nonconductive means when said second contact means is in engagement with said first contact means, and means actuable when said second contact means is moved into its closed position to release said nonconductive means towards said covering relation and into engagement with said first contact means, movement of said second contact means out of engagement with said first contact means being operable to release nonconductive means for movement into said covering relation whereby any are struck between said first contact means and said conductive portion will be extinguished.

13. A disconnecting device including contact means, elongate switch means having a conductive portion and being mounted for movement of said conductive portion into and out of engagement with said contact means, nonconductive means disposed in surrounding relation to at least a portion of said elongate switch means, means resiliently urging said nonconductive means toward said conductive portion, latch means for holding said nonconductive means away from said conductive portion when said conductive portion is out of engagement with said contact means, said contact means including means engageable by said nonconductive means when said conductive portion is in engagement with said contact means and release means actuable when said conductive portion is moved into engagement with said contact means to release said latch means and allow said resilient means to urge said nonconductive means toward said conductive portion and into engagement with said contact means, movement of said switch means out of engagement with said contact means being operable to release said nonconductive from movement onto said conductive portion whereby any are struck between said contact means and said conductive portion will be extinguished.

14. A load break disconnecting device including contact means, elongate switch means having a conductive portion and being mounted for movement of said conductive portion into and out of engagement with said contact means, nonconductive means disposed in surrounding relation to substantial portion of said elongate switch means and being mounted for sliding movement longitudinally therealong, spring means disposed within said nonconductive means for resiliently urging the latter toward said conductive portion, said switch means having an aperture formed therein adjacent said conductive portion, spring latch means disposed within said switch means and having a latch tip extending through said aperture to prevent movement of said nonconductive means toward said conductive portion, trip means associated with said contact means and engageable with said latch tip when said conductive portion is moved into engagement with said contact means to release said nonconductive means for movement toward said conductive portion and into engagement with said contact means, movement of said conductive portion out of engagement with said contact means being operable to release said nonconductive means for movement onto said conductive portion whereby any arc struck between said contact means and said conductive portion will be extinguished.

References Cited by the Examiner UNITED STATES PATENTS 1,833,173 11/1931 Murray 200-151 References Cited by the Applicant UNITED STATES PATENTS 649,554 5/1900 Schwedtmann. 2,262,386 11/1941 Crabbs.

2,277,422 3/ 1942 Walle. 2,294,801 9/ 1942 Rawlins. 2,591,950 4/1952 Lindell.

FOREIGN PATENTS 604,498 9/1960 Canada.

KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT S. MACON, Examiner.

Claims

2. A LOAD BREAK DISCONNECTING DEVICE COMPRISING STATIONARY CONTACT MEANS, ELONGATE SWITCH MEANS HAVING A CONDUCTIVE PORTION AND BEING MOUNTED FOR MOVEMENT OF SAID CONDUCTIVE PORTIONINTO AND OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACT MEANS, NONCONDUCTIVE MEANS MOUNTED ON SAID ELONGATE SWITCH MEANS FOR MOVEMENT INTO AND OUT OF COVERING RELATION OF SAID CONDUCTIVE PORTION RELATIVE TO SAID STATIONARY CONTACT MEANS, MEANS RESILIENTLY URGING SAID NONCONDUCTIVE MEANS TOWARD SAID COVERING RELATION, MEANS FOR HOLDING SAID NONCONDUCTIVE MEANS AWAY FROM SAID CONDUCTIVE PORTION, ASND RELEASE MEANS ACTUABLE WHEN SAID ELONGATE SWITCH MEANS IS MOVED INTO ITS CLOSED POSITION TO RELEASE SAID NONCONDUCTIVE MEANS TOWARD SAID COVERING RELATION AND INTO ENGAGEMENT WITH SAID STATIONARY CONTACT MEANS, MOVEMENT OF SAID SWITCH MEANS OUT OF ENGAGEMENT WITH SAID STATIONARY CONTACT MEANS BEING OPERABLE TO RELEASE SAID NONCONDUCTIVE MEANS FOR MOVEMENT INTO SAID COVERING RELATION WHEREBY ANY ARC STRUCK BETWEEN SAID STATIONARY CONTACT MEANS AND SAID PORTION WILL BE EXTINGUISHED.