US2954449A - Switch construction - Google Patents

Description

Sept. 27, 1960 s. l. LINDELL SWITCH CONSTRUCTION 6 Sheets-Sheet 1 Filed Sept. 25, 1958 INYENTOR. fi QA/dflUZdZL BY M W 4% watikwkq rwmmm 33% Sept. 27, 1960 s. l. LINDELL 2,954,449

- SWITCH CONSTRUCTION Filed Sept. 25, 1958 I s Sheets-Sheet 2 A 7/M50L/47/0/V g 79 63 6 f g3 M INVENTOR.

Sept. 27, 1960 s. l. LINDELL 2,954,449

SWITCH CONSTRUCTION Filed Sept. 25. 1958 6 Sheets-Sheet a INVENTOR.

Sept. 27, 1960 s. LINDELL 2,954,449

SWITCH CONSTRUCTION Filed Sept. 25, 1958 6 Sheets-Sheet 4 INYENTOR.

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SWITCH CONSTRUCTION Filed Sept. 25, 1958 6 Sheets-Sheet 6 INVENTOR. fl guraflazdefli nited States Patent SWITCH-CONSTRUCTION Sigurd I. Lindeil, Chicago, Ill., assignor to S & C Electric Company, Chicago, lll.,va corporation of Delaware Filed Sept. 25, 1958,,Ser. No. 763,383

6 Claims. (Cl; 200146) This invention relates, generally, to'the construction of load break disconnecting switches and it: has particular relation to the sequence of operation'tliereof. This invention is an improvement over the invention disclosed in application Serial No; 748,912, filed July 16, 1958, and assigned to the assignee of this application.

In the copending application above referred to there is disclosed a disconnectingswitch construction provided with a load current interrupter. The load current interrupter is intended for eifecting the final opening of the circuit after the switch blade is moved out of engagement with a cooperating stationary contact. After this takes place and the switch blade has been moved well beyond the distance where an arc might restrike between the switch blade and the. stationary contact, the load current interrupter is operated to' open the circuit in such manner that no external arc is drawn. The contacts of the load current interrupter are arranged and constructed to interrupt satisfactorily load currents up to the normal load current carrying capacity of the disconnecting switch. When the switch blade is swung to the closed position, there is the possibility'that the circuit may be completed on a fault. In that case current flow will take place substantially in excess ofth'e normal load current flow through the'switch. Since the contacts of the load current interrupter are intended to conduct normal load current only momentarily when the switch is being opened and to interrupt the same, severe damage may be incurred by these contacts if the switch should be closed under short circuit conditions and the circuit first completed through the contacts of the load current interrupter. In accordance with the construction disclosed in the copending application, provision is made for closing the contacts of the load current interrupter as the switch blade approaches the switch closed position. Provided that the movement of the switch blade toward the closed position is sufiiciently slow, the circuit will be completed first between the switch blade and the stationary switch contact and will not be completed at the contacts of the load current interrupter. However, if the switch blade is moved rapidly toward the switch closed position, which is desirable in order to limit the duration of arcing at the contact engaged by the blade, and the movable contact of the load current interrupter is initiated in its movement toward the closed position, the energy imparted thereto by impact of the fast moving switch blade assembly may be sufficient to cause the movable contact to move in advance of the movement of the switch blade such that the circuit will be completed at the contacts of the load current interrupter.

Accordingly, among the objects of this invention are:

To provide for initiating the closure of the contacts of r the load current interrupter only after the switch blade has been swung toward the closed position sufliciently far to positively establish the circuit therethrough at the voltage' at which the switch is intended tooperate; to: engage the: closing trigger of the load current interrupter only after the switch blade has been swung toward the closed position sufliciently far to'complete the circuit toa stationary contact by an are initiated at the voltage at which the switch is intended to operate; to operate the switch blade by a mechanism that moves it quickly and positively to the switch closed position; and to operate the interrupter contacts from the fully open position to the closed position after the circuit has been established through the switch blade and a stationary contact in combination with means for positively opening the interrupter contacts after the switch blade has been disengaged from the stationary contact.

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

This invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of'construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth and the scope of theapplication of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

Figure l is a view, in front elevation, of a three phase load interrupter switch installation in each pole of which the present invention is embodied;

Figure 2 is a view, in side elevation, showing one pole of the three phase load interrupter switch installation, shownin Figure l, certain parts being broken away and others being shown in section in order to illustrate more clearly the details of construction;

Figure 3 is a view, partly in side elevation and principally in vertical section, showing the details of construction of the load interrupter, the illustration showing the contactsof'the load interrupter in the closed position;

Figure 4 is a view, similar to Figure 3, but showing the load interrupter contacts in the open position;

Figure 5 is a view, similar to Figure 2', but showing the switch blade being moved toward the open-positionwith the opening cam engaging: the-opening trigger of the load current interrupter, no movement of the movable contact of the load current interrupter having taken place;

Figure 6 is a view, similar to Figure 2, but showing the switch blade in the full open position with the triggers of the load current interrupter shown in the positions that they occupy when the movable contact of the load current interrupter is in the open position as shown in Figure 4;

Figure 7 is a view, similar to Figure 2, but showing the switch blade being moved toward the switch closedposition to a location where an arc can be struck between it and the stationary switch contact at the voltage at which the switch is intended to operate with the closing cam engaging the closing trigger of the load current interrupter but no movement of the movable contact thereof having taken place from the position shown in Figure 4; and

Figure 8' is a top plan view taken generally along the line 8-8 of Figure 7 and showing the relationship between the contact tip on the stationary switch contact and the arcing contact buttons carried by the switch blade at the time that the latter has been moved within striking distance of the stationary switch contact.

Referring now particularly to Figure l of the drawings, it will be observed that the reference character 10 designates, generally, a frame formed of structural rolled steel sections that may include frame uprights 11 and 12 on which insulating barriers 13 are mounted. It will be noted that the insulating barriers 13. are positioned between load interrupter disconnecting switches each of which is indicated, generally, at 14. Three disconnecting switches 14 are employed for a three phase installation.

Where single phase operation is required it will be understood that only a single load interrupter disconnecting switch 14 is used. Since the construction of the load interrupter disconnecting switches 14 is identical for each, a description of one will suffice for all of them.

The load interrupter disconnecting switches 14 are mounted on upper and lower transverse angle members 15 and 16 which are secured suitably to the frame uprights 11 and 12 at their ends. It will be understood that other mounting means can be employed if desired. Upper and lower insulators 17 and 18 are provided for each load interrupter disconnecting switch 14 and they are secured by bolts 19 and 20 to the upper and lower transverse angle members 15 and 16 as shown.

At their outer ends the upper and lower insulators 17 and 18 have secured thereto upper and lower line terminals that are indicated, generally, at 21 and 22 respectively. The terminal members 21 and 22 are provided with terminal pads 23 and 24 to permit connection of line conductors. The upper line terminal has a contact tongue 25 formed integrally therewith and projecting outwardly therefrom while the lower line terminal 22 has a hinge member 26 formed integrally therewith and projecting outwardly therefrom. The upper and lower line terminals 21 and 22 are arranged to be interconnected by a switch blade that is indicated, generally, at 27 and is pivoted at 28 to the hinge member 26. The switch blade 27 preferably is formed by a pair of switch blade members 29 and 30 that are spaced apart a substantial distance for the principal portion of their length and engage opposite sides of the hinge member 26 at their lower ends. Each switch blade member near its upper end is bent inwardly as indicated at 31 in Figure 1 to provide a contact section 32 at the upper end with these contact sections being arranged to engage opposite sides of the contact tongue 25 which is relatively thin as compared to the width of the hinge member 26. It will be pointed out hereinafter wherein additional arcing contact construction is provided at the upper end of the switch blade 27 for each of the load interrupter disconnecting switches 14 to insure that the circuit is completed between the contact tongue 25 and the switch blade 27 when the latter is moved to the closed position before the circuit is completed through a load current interrupter to be described. It will be understood that the insulators 17 and 18 are mounted on the frame 10 in the manner described and serve to position the upper and lower line terminals 21 and 22 in insulated spaced relation and that the switch blade 27 is arrranged to interconnect them when it is in the closed position as shown in Figures 1 and 2 of the drawings.

It is desirable that an operating mechanism be provided for quickly moving the switch blade 27 from the switch closed position shown in Figures 1 and 2 of the drawings to the open position shown in Figure 6 and for quickly swinging it to the closed position for completing the circuit in order to limit the duration of arcing on opening and closing of the circuit. For this purpose a quick make quick break operating mechanism indicated at 33 in Figure 1 is employed. This mechanism can be motor operated or it can be spring driven and manually actuated as may be desired. The specific arrangement and construction of the quick make quick break operating mechanism 33 form no part of the present invention other than to point out that such a mechanism is employed which is capable of moving the switch blade 27 from and to the switch closed position relatively rapidly and to insure complete closing movement of the switch blade 27 and limit arcing during such closing movement and closing of the contacts of the load current interrupter (to be described) automatically once the circuit has been established through the switch blade and contact tongue 25. This provides for full continuous current carrying capacity of the switch and for interruption of load current by the load current interrupter in proper sequence 4 when the operation of the mechanism takes place in opposite direction to open the switch.

For interconnecting the quick make quick break operating mechanism 33 and each switch blade 27 of the three load interrupter disconnecting switches 14 three links 35 of a suitable insulating material are used. At one end each link 35 is pivoted at 36 to the respective blade switch blade 27. At its other end each link 35 is pivoted at 37 to an arm 38. The arms 38 are secured to a horizontally extending shaft 39 which is journaled on the frame 10 in suitable bearings 40 which can be mounted on the frame uprights 11 and 12. The shaft 39 extends to have operative connection with the quick make quick break operating mechanism 33 which is capable, as pointed out above, of rotating the shaft 39 in one direction to simultaneously open the switch blades 27 and in the opposite direction to close them simultaneously, in each instance at a relatively high speed.

When each switch blade 27 is moved to the open position, it is undesirable that any are be formed between it and its upper line terminal 21. More specifically, it is desired that no are be formed under these conditions between the contact sections 32 and the contact tongue 25. Accordingly, the upper line terminal 21 is provided with a depending contact plate 43 and an integrally formed socket 44 with respect to which a load current interrupter, shown generally at 45, is detachably secured by a bolt 46 as described in US. Patent No. 2,621,272, issued December 9, 1952.

Figures 3 and 4 of the drawings show the details of construction of the load current interrupter 45. There it will be observed that it includes a contact plate 47 which is arranged to overlie the depending contact plate 43 and to be secured thereto by the bolt 46. Threaded into the lower portion of the contact plate '47 is a metallic plug sleeve 48 which is provided at its inner end with a stationary load interrupter contact 49. Since the contact plate 47 is secured to the contact plate 43 which is formed integrally with the upper line terminal 21 and since the plug sleeve 48 is threaded into the contact plate 47, the stationary load interrupter contact 49 is connected directly to the upper line terminal 21.

The load current interrupter 45 also includes a movable load interrupter contact 50 Which, as shown in Figure 3 of the drawings, is in contact engagement with the stationary contact 49 when the load interrupter 45 is in the closed position and the switch blade 27 also is in the closed position. The movable contact 50 is carried at one end of a contact rod 51 that is pivoted at 52 at its other end to an operating mechanism which is indicated, generally, at 53. The operating mechanism 53 is contained within a metallic housing 54 and it includes a link 55 to which the contact rod 51 is pivoted at 52. The other end of the link 55 is pivoted at 56 to one end of a link 57 and the other end is pivoted at 58 to the housing 54. Formed integrally with the link 57 is a stop 59 which limits the movement of the operating mechanism 53 in either the closing or opening direction. livoted at 6t intermediate the pivots 52 and 56 on the link is an arm 61 the other end of which is fastened to the rock shaft 62 that is journaled on the housing 54 with its ends projecting therethroug h to opposite sides. At one end of the rock shaft 62 there is fastened a closing trigger 63 which is shown by full lines in Figures 2, 5, 6 and 7 of the drawings and by broken lines in Figure 3. At the other end of the rock shaft 62 there is an opening trigger 64 which is angularly spaced, as shown in Figure 3, from the closing trigger 63. A toggle spring 65 interconnects the pivots 56 and the rock shaft 62 for the pur-- pose of providing a snap action in the movement of the contact rod 51 and for holding it in either the closed position shown in Figure 3 or the open position shown in Figure 4 of the drawings.

Any are that is formed on separation of the movable load interrupter ontat 50 from the stationary load inana yses terrupter contact as is drawn in a bore 66 that is formed in a stack 67 of fiber washers which are surrounded by an insulating sleeve 68. One end of the insulating sleeve 68 is threaded into the lower portion of the contact plate 47 while the other end is threaded into a tubular extension from the metallic housing 54. Additional insulation is provided between the contact plate 47 and the metallic housing 54 by a tubular porcelain insulator 69. The are is confined within the bore 66 by a trailer 70 that is formed of suitable insulating material and is connected to the contact rod 51 and moves simultaneously with it and with the movable contact 50. Since the only time that current flows through the contact rod 51 is during the circuit opening operation, it is-unnecessary to provide an extremely low resistance path to the switch blade 27. Accordingly, the circuit extends from the contact rod 51 through the links 55 and 57 and 61 to the metallic housing 54. The circuit to the switch blade 27 extends through a bow contact 73 that is carried thereby, as indicated in Figure 2, and which is'arranged to engage projections '74 on the metallic housing 54 during the time that the switch blade is moved away from or toward the contact tongue 25 of the upper line terminal 21.

It will be recalled that the arrangement of the load current interrupter 45 is such that the circuit is opened between the contacts 49 and 50 when the switch blade 27 is swung'to the open position. In order to accomplish this an opening cam 75, Figure 6, is secured by rivets 76 to the switch blade member 30. The opening cam 75 has a cam surface 77 that faces away from the pivot axis 23 of the switch blade 27 and is arranged to engage the left side of the opening trigger 64, as shown in'Figure 5, asthe switch blade 27 is swung to the open position. The continued movement of the switch blade 27 in the opening direction brings the bow contact 73 into engagement with metallic housing 54 with the result that, before the contact sections 32 of the switch blade members 29 and 3t disengage the contact tongue 25, a shunt circuit is provided therebetween through the load interrupter 45. After a sufficient gap has been introduced between the switch blade 27 and the contact tongue 25, the opening cam 75 engages the opening trigger 64. This positively causesthe rock shaft 62 to be rotated in a counterclockwise direction as viewed in Figure 3 of the drawings with the result that contact 50 cannot fail to move out of engagement with the stationary contact 49 and the arc is drawn and extinguished within the bore 66. Figure 4 of the drawings shows the relative positions of the movable parts of the load current interrupter 45 when it is in the open position. It will be noted that the opening trigger 64 has been swung in a counterclockwise direction from its position shown in Figure 3 and that a corresponding movement of the closing trigger 63 has taken place.

When the switch blade 27 is in the fully open position it can occupy the position shown in Figure 6. Here the closing trigger 63 is shown in the position that it occupies, as shown in Figure 4, when the load current interrupter 45 is in the open position.

As pointed out in the copending application above referred to, it is desirable that the circuit not be closed through the load interrupter 45 on initial engagement of the movable contact 5t? with the stationary contact 49 in the load current interrupter 45 or when the switch blade 27 comes close enough to the contact tongue 25 for an arc to be struck when the switch blade 27 is moved toward the closed position. Accordingly, as disclosed in the copending application, provision is made for delaying the closing or" the load current interrupter 45 until the circuit has been completed between the switch blade 27 and the contact tongue 25 of the upper line terminal 21. For this purpose there is secured by rivets 78, Figure 2, to the switch blade member 29 and arm 79 which extends from the switch blade 27 in the direction of opening movement thereof. At the outer end of the arm 79 there is secured by'rivets itla closing c-a'm 81-Which has a cam surface SZ' tha-t faces outwardly or away from the pivot axis 28'and is arranged to engage the right hand side of the closing trigger 63 when the switch blade 27 is moved toward the closed position.

As pointed out hereinbefore, when the switch blade 2'7 is moved quickly toward the switch closed position and the camsurface 32 of the closing 81 engages the closing trigger 63', there is the possibility that sufiicient energy may be imparted into the. operating mechanism 53, contact rod 51, movable load interrupter contact 59 and traiier 70 that will cause the movable load interrupter contact 56 to move in advance of the movement of the Switchblade 27 to such an extent that it will approach the stationary load interrupter contact 49 and complete the circuit before the circuit is completed between the switch blade 27 and the contact tongue 25 on the upper line terminal 21} Under these circumstances the circuit is first completed-between the contacts 49 and 5tl'of the load current interrupter 45 and, if the circuit is closed on a fault, substantially more current will flow through the contacts 49' and 50' than they are intended to carry. They become burned and pitted. In addition the heat of the arc incident to such operation may vaporize adjacent portions of the stack of fiber washers 67 and cause the bore 66 to be severely eroded, Then, before a subsequent operation of the load interrupter disconnecting switches 14 takes place, the load current interrupters 45 should be removed andrepaired.

in accordance with this invention provision is made for insuring that under no circumstances will the circuit be completed between the'contacts 4-9'and 50 of the load current interrupter 55' before the circuit is completed directly between the switch blade 27' and the contact tongue 25 on the upper line terminal 21.

As shown more clearly in Figure 5 of the drawings the contact tongue 25 is provided with an upwardly extending" contact extension 85' that has an integrally formed arm 86 which extends toward the switch blade 27. On the under side of the arm 86 there is a cylindrical arcing contact tip 87, formed of suitable are resisting material, and it is held in place by a stainless steel cap screw 88; For cooperating with the cylindrical arcing contact tip 87 a pair ofarcing contact buttons $39 are provided asshown more clearly in Figure 8' of the drawings; The arcing contact buttons 59, like the arcing contacttip .87, are forme'd'of'arc resisting material and are arranged either to lightly engage opposite sides of the tip 87 or to movein close proximity thereto but not in mechanical engagement therewith when the switch blade 27 is moved toclosed'po'sition. They are held in place by bolts 90 on the upper ends 91 of switch blade extensions 92; The switch blade extensions $2 have outstanding foot portions 93 which are secured by rivets 94 to the inwardly bent portions 31 of the switch blade members 29 and 30. The auxiliary contact extension 85, arm 86' and'tip 37 not only permit initiating the arc in conventional manner to limit the damage to the contact tongue 25 in closing on a fault but also they provide for more travel of the switch blade 27 to operate the load current interrupter to closed position after the circuit is established by the arc.

When the switch blade 27 is in the switch closed position as shown in Figure 2 of the drawings, the circuit is completed through it between the upper and lower terminals 21 and 22. When the switch blade 27 is swung toward the open position as indicated by the arrow 95, Figure 5, the bow contact 73 engages one of the pro jections 74 on the underside of the metallic housing and thereby places the load current interrupter -35 in shunt with the upper line terminal 21 and switch blade 27. The opening movement ofthe switch. blade 27 continues in the direction indicated by the arrow 95 until the cam surface 77 on the opening cam 75 engages the left hand side of the opening trigger 64. At this time the distance indicated at 96 between the arcing contact tip 87 and the nearest part of one or the other of the switch blade extensions 92 is such that, if the circuit were at that time opened by the load current interrupter 45, no arc would be restruck directly between the switch blade 27 and the upper line terminal 21. Thereafter the opening movement of the switch blade 27 is accompanied by a rotation of the rock shaft 62 and the circuit is opened by separation of the movable load interrupter contact 50 from the stationary load interrupter contact 49 within the bore 66 and the arc incident to such operation is there drawn and extinguished. The movement of the switch blade 27 as operated by the quick make quick break operating mechanism 33 continues to the full open position shown in Figure 6 of the drawings. At this time the parts of the load current interrupter 45 are positioned as shown in Figure 4 of the drawings. When the quick make quick break operating mechanism 33 is energized to move the switch blade 27 toward the closed position as indicated by the arrow 97 in Figure 7 of the drawings, the operation continues with the circuit remaining open until, as shown in Figure 8 of the drawings, the arcing contact buttons 89 approach the arcing contact tip 87 to the distance indicated at 98. The distance 98 from the arcing contact tip 87 to one or the other of the arcing contact buttons 89 is such that, at the rated voltage of the load interrupter disconnecting switch 14, an arc will be initiated between one or the other of the arcing contact buttons 89 and the contact tip 87. In the event that the circuit is being closed on a fault, the current flow through such an arc will be of corresponding magnitude. Its duration will be relatively short for the reason that the switch blade 27 is moved at a high speed by the quick make quick break operating mechanism 33 to the switch closed position.

At the time that the arcing contact buttons 89 are within arcing distance, as indicated at 98, of the arcing contact tip 87, the cam surface 82 on the closing cam 81, Figure 7, first engages the right hand side of the closing trigger 63. The arrangement is such that no movement of the closing trigger 63 or movement of the movable load interrupter contact 50 is initiated until the switch blade 27 has been swung to such a position that the arcing contact buttons 89 are brought into are striking distance 98 from the arcing contact tip 87. Thereafter, continued movement of the switch blade 27 in the direction indicated by the arrow 97 is accompanied by movement of the closing trigger 63 and corresponding movement of the movable load interrupter contact 50 back to the closed position shown in Figure 3. Since no movement of the movable load interrupter contact 50 is initiated until after the circuit is completed through the are established between one or the other of the arcing contact buttons 89 and the arcing contact tip 87, there is no possibility that the circuit will be completed under fault current conditions or any other conditions between the contacts 49 and 50 of the load current interrupter 45.

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

What is claimed as new is:

1. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts and movable into and out of engagement with one of said switch contacts, a load current interrupter including separable interrupter contacts and operating means for opening and closing said interrupter contacts, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion of its movement into and out of engagement with and adjacent to said one switch contact, means cooperating with said operating means on movement of said switch blade to open position to open said interrupter contacts after said switch blade disengages said one switch Contact, means holding said interrupter contacts in open position after operation to open position in response to said movement of said switch blade to open position, means on said switch blade for mechanically engaging said operating means to overcome said holding means and initiate the closure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has been moved to a position where a circuit is established between it and said one switch contact at the voltage rating of the switch construction thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough prior to completion of the circuit between said switch blade and said one switch contact.

2. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts and movable into and out of engagement with one of said switch contacts, a load current interrupter including separable interrupter contacts and operating means for opening and closing said interrupter contacts, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion of its movement into and out of engagement with and adjacent to said one switch contact, means cooperating with said operating means on movement of said switch blade to open position to open said interrupter contacts after said switch blade disengages said one switch contact, means holding said interrupter contacts in open position after operation to open position in response to said movement of said switch blade to open position, means on said switch blade for mechanically engaging said operating means to overcome said holding means and initiate the closure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has been moved to a position where a circuit is established between it and said one switch contact at the voltage rating of the switch construction thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough prior to completion of the circuit between said switch blade and said one switch contact, and quick operating mechanism mechanically connected to said switch blade for positively moving it from open to closed position at such a speed that the time is relatively short during which an arc is maintained between said one switch contact and said switch blade before said switch blade has contact engagement with said one switch contact.

3. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts and swingable into and out of engagement with one of said switch contacts, an arcing contact on said one switch contact extending therefrom in the direction of opening movement of said switch blade and first approached thereby on closing movement thereof, a load current interrupter including separable interrupter contacts and operating means for opening and closing said interrupter contacts, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion of its movement into and out of engagement with and adjacent to said one switch contact, means on said switch blade cooperating with said operating means on movement of said switch blade to open position to open said interrupter contacts after said switch blade disengages said arcing contact, means holding said interrupter contacts in open position after operation to open position by said means on said switch blade, and means on said switch blade for mechanically engaging said operating means to overcome said holding means and initiate the closure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has swung to within arcing distance of said arcing contact at the voltage at which the switch construction is tended to be operated thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough until after the circuit is established between said switch blade and said arcing contact.

4. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts and swingable into and out of engagement with one of said switch contacts, an arcing contact on said one switch contact extending therefrom in the direction of opening movement of said switch blade and first approached thereby on closing movement thereof, a load current interrupter mounted on the one switch contact and including separable interrupter contacts and operating means for opening and closing said interrupter contacts, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion of its movement into and out of engagement with and adjacent to said one switch contact, means holding said interrupter contacts in open position after operation to open position by said means on said switch blade, means on said switch blade for mechanically engaging said operating means to overcome said holding means and initiate the closure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has swung to within arcing distance of said arcing contact at the voltage at which the switch construction is intended to be operated thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough until after the circuit is established between said switch blade and said arcing contact, and quick operating mechanism mechanically connected to said switch blade for positively moving it from open to closed position at such a speed that the time is relatively short during which an arc is maintained between said arcing contact and said switch blade before said switch blade has contact engagement with said one switch contact.

5. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts comprising a pair of parallel spaced apart elongated blade members swingable into and out of engagement with one of said switch contacts, an arcing contact on said one switch contact extending therefrom in the direction of opening movement of said switch blade and first approached on opposite sides by a pair of arcing tips on said switch blade on closing movement thereof, a load current interrupter mounted on said one switch contact and including separable interrupter contacts and operating means for opening and closing said interrupter contacts including a pair of triggers on said load current interrupter and spaced from said switch blade when closed in the direction of opening movement thereof, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion of its movement into and out of engagement with and adjacent to said one switch contact, means on one of said blade members cooperating with said operating means on movement of said switch blade to open position to engage one trigger to open said interrupter contacts after said arcing tips disengage said arcing contact, and means on the other blade member for mechanically engaging the other trigger to initiate the closure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has swung to position at least one of said arcing tips within arcing distance of said arcing contact at the voltage at which the switch construction is intended to be operated thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough until after the circuit is established between said one arcing tip and said arcing contact.

6. A switch construction for opening and closing a high voltage current carrying circuit comprising, in combination, a pair of switch contacts in insulated spaced relation, a switch blade for bridging said switch contacts comprising a pair of parallel spaced apart elongated blade members swingable into and out of engagement with one of said switch contacts, an arcing contact on said one switch contact extending therefrom in the direction of opening movement of said switch blade and last engaged between a pair of arcing tips thereon on opening movement thereof and first engaged therebetween on closing movement thereof, a load current interrupter mounted on said one switch contact and including separable interrupter contacts and operating means for opening and closing said interrupter contacts including a pair of triggers on said load current interiupter and spaced from said switch blade when closed in the direction of opening movement thereof, one of said interrupter contacts being electrically connected to said one switch contact and the other interrupter contact being electrically connected to said switch blade during that portion or" its movement into and out of engagement with and adjacent to said one switch contact, means on one of said blade members cooperating with said operating means on movement of said switch blade to open position to engage one trigger to open said interrupter contacts after said arcing tips disengage said arcing contact, means on the other blade member for mechanically engaging the other trigger to initiate the ciosure of said interrupter contacts on movement of said switch blade toward closed position only after said switch blade has swung to position at least one of said arcing tips within arcing distance of said arcing contact at the voltage at which the switch construction is intended to be operated thereby positively preventing the closure of said interrupter contacts and completion of a circuit therethrough until after the circuit is established between said one arcing tip and said arcing contact, and quick operating mechanism mechanically connected to said switch blade for positively moving it from open to closed position at such a speed that the time is relatively short during which an arc is maintained between said arcing contact and said one arcing tip before said switch blade has contact engagement with said one switch contact.

References Cited in the file of this patent UNITED STATES PATENTS 2,351,826 Lindell et a1. June 20, 1944 2,469,203 Palme et a1 May 3, 1949 2,480,622 Warnock Aug. 30, 1949 2,712,577 Stene July 5, 1955

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