US2527269A - Switch means - Google Patents

Description

Oct. 24, 1950 5, c, K L N 2,527,269

SWITCH MEANS Filed Dec. 11, 1946 3 Sheets-Sheet l KUBBE/E STOP Oct. 24, 1950 I 5, c, KILUAN 2,527,269

. SWITCH MEANS Filed Dec. 11, 1946 3 Sheets-Sheet 3 fizz/672207" 21 I nr/@M% m M Patented Oct. 24, i930 SWITCH MEANS Stanley 0. Killian, Glen Ellyn, Ill., assignor to The Delta-Star Electric Company, Chicago, 111., a corporation of Illinois Application December 11, 1946, Serial No. 715,364

9 Claims. (Cl. 200--144) My invention relates, generally, to switches and it has particular relation. to load break switches for use in high voltage alternating current power circuits, such as circuits energized at voltages of the order of 23,000 volts and upwardly. However, it will be understood that it may be used for opening circuits operating at lower voltages.

Among the objects of my invention are: To open the circuit through a disconnecting switch by a load break device in which the arc incident to the circuit opening is quickly and efficiently ex tingu'ished; to separate the contacts of the load break device by the rotary movement of a drum carrying one of them; to extinguish the are between the contacts by drawing it in a restricted passageway formed of material capable of evolving an arc extinguishing medium due to the heat of the arc; to rotate the drum by unwinding a flexible conductor therefrom that is connected to the contact thereon and winding it on a spring biased spool; to release the spoolfor operation by' its spring when the blade of the disconnecting switch reaches a predetermined position; to restore the drum to the circuit closed position and tension the spring by movement of the switch blade to the closed position; to accommodate and. extinguish relatively low and relatively high current arcs; to damp the rotation of the drum near the final movement thereof for cushioning the shock incident to stopping of the same; and to direct an air blast into the arc passageway created by the movement of the drum for extending and assisting in extinguishing the arc therein.

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

Myinvention is disclosed in the accompanying drawings and it comprises the features of construction, combinationof elements and arrange ment of parts which will be exemplified in the description hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

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

which:

Figure 1 is a view, in side elevation, of a conventional. form of disconnecting switch with which the load break device of the present invention may be used;

Figure '2 is a View, in front elevationfof the switch construction shown in Figure 1;

2 Figure 3 is a view, in side elevation, at a reduced scale of the load break device shown in Figures 1 and 2, the switch blade being shown in the partially opened position; Figure 4 is a detail sectional view, taken along the line 44 of Figure 5; Figure 5 is a view, in side elevation, of the load breakdevice in the closed position, one of the side plates having been removed and certain parts being broken away to show more clearly the details of construction; e Figure 6 is a detail sectional view of a portion of the drum and housing, showing a modified form of arc passageway for small current arcs; Figure '7 is a view, similar to Figure 5, and showing a modification of the drum on which one of the contacts is mounted; and

Figure 8 is a plan View of the drum shownin Figure-7.

Referring now particularly to Figures 1 and 2 of the drawings, it will be noted that the reference characters l and II designate'insulators of porcelain or the like which are arranged to carry switch, contacts l2 and 13, respectively. The switch contacts are provided with pads l4 and I for receiving line terminals. The switch contacts l2 and 13 may be interconnected by a switch blade, shown generally at l6, comprising a pair of blade members l8--l8, which may be hinged by a bolt IS on the lower switch contact 13. 2 Any suitable means can be provided for operating the switch blade Hi from and to the closed position. For example, it may be providedwith extensions from the blade members I8 having apertures 22 near their outer ends for receiving the operating member of a gang operating mechanism. The switch blade I6 also can be arranged for hook stick operation, as will be understood readily.

At their upper ends the switch blade members l8 are held together by a bolt 24 which has an extension 25 that is arranged to operate a load break device, shown generally at 30, in a manner which will be described in detail hereinafter. It will be understood that the load break device may be employed with other types of disconnecting switch or that it may be employed as a switch in itself without being arranged as an auxiliary to a disconnecting switch or the like. The load break device 30 may be mounted by a flange 3| that forms a part of the upper switch contact 42 and it may be secured thereto by any suitable means, such as by screws 32. The

load break device 30 includes an insulating hous ing, designated generally at 33, which comprises a frame 34 and side plates 35 and 36.

The insulating housing 33 not only carries the contacts of the load break device, between which the circuit is finally interrupted but also, as will appear hereinafter, it forms a part of a passageway in which the arc between the contacts is drawn. Since it is desirable to extinguish the are quickly and expeditiously, it is preferable to form the passageway by material that is capable of evolving an arc extinguishing medium when subjected to the heat of the arc. Accordingly, the frame 34 and side plates 35 and 36 preferably are formed of such a material. Any of the well known arc extinguishing materials may be used, such as fiber, various resins and the like. The frame 34 and side plates 35 and 36, of fiber or the like, may be held in a unitary construc tion by any suitable means, such as the screws 31.

The details of construction of the load break device 36 are illustrated more clearly in Figures 4 and of the drawings. As shown in Figure 5 one of the contacts 48 of the load break device may be slidably mounted in a suitable aperture 4| in the frame 34. A coil compression spring 42 serves to bias the contact radially inwardly for a, purpose which will be described presently. A flexible conductor 43 serves to interconnect the contact 46 and the upper switch contact 12. As shown in Figure 1, the flexible conductor 43 may be clamped by a clamp screw 44 to an extension 45 that is integrally formed with the upper switch contact 12.

The contact 40, which may be considered to be a relatively stationary contact, is arranged to engage a plate-like contact 4'! that is carried by a drum 48. In this case the contact 41 may be considered to be a relatively movable contact with respect to the relatively stationary contact 48.

The drum 48 is mounted for rotation within a circular opening 49 in the frame 34 and is spaced therefrom by a gap which is indicated at 50. Since the are which is drawn on separation of the contacts 40 and 41 occupies a portion of the gap 50, it is preferable that the portion of the drum 48 which is subjected to the action of the arc be formed of a material similar to that which is employed for making up the frame 34 and the side plates 35 and 36. Accordingly, the drum 48 may be formed of a circular disc of fiber and it may have apertures 51 therein to reduce the weight thereof.

The drum 48 may be mounted for rotation with a shaft 52 to which it may be secured by means of a key 53. As shown in Figure 1, the shaft 52 extends through the side plate 36 and carries an operating arm 54 which may be secured thereto by a key 55. The operating arm 54 is positioned in the path of the extension 25 of the bolt 24 so that it can be engaged and rotate the drum 48 to move the contact 41 back into engagement with the contact 40, when the switch blade [8 is operated to the closed position. This relationship is shown more clearly in Figure 3.

It is desirable to limit the movement of the drum 48 in the opening direction. As will appear hereinafter, its movement in this direction is at a relatively high speed in order to effect rapid separation of the contacts 48 and 4'1. It must be arrested by means which will absorb the shock and still leave the apparatus uninjured. For this purpose a rubber stop or bumper 56 may be secured by clamp 51 to the side plate 36, as illustrated in Figures 1 and 2 of the draw ings. Additional means, which will be described in detail hereinafter, may be employed for damping the movement of the drum 48 and cushioning the shock incident to the stopping thereof.

It will be observed that the plate-like contact 41 is relatively long andthat it remains in contact engagement with the contact 40 for a substantial distance from the initial position shown in Figure 5. One reason for this construction is to permit the drum 48 to be brought up to speed before the contact 41 is moved out of engagement with the contact 46 and the circuit opened. Because of this arrangement, when the circuit is opened, the action takes place at a relatively high speed as compared to the speed at which it would take place if, on initial movement of the drum 48, the contact 41 were moved out of engagement with the contact 40.

The contact 41 is located in a suitable recess in the periphery of the drum 48. It may be connected to the switch blade I6 by suitable conducting means which includes a flexible conductor 60 which serves not only to make electrical connection to the contact 41 but also serves to provide a mechanical connection to the drum 48 for rotating the same. The flexible conductor 66 may be located in a suitable peripheral groove 61 in the drum 48. It is trained over the drum 48 in the groove 6! and onto a. spool 62 of metal, such as brass, that is rotatably mounted in the lower portion of the frame 34 on a shaft 63. This is illustrated more clearly in Figure 4 of the drawings. Within the spool 62 there may be provided a spiral spring 64. One end of the spring 64 is connected to the spool 62, while the other end is connected to the shaft 63. The shaft 63 itself is rotatably mounted and has a section 65 of reduced diameter that projects through and is journaled in a cover plate 66. A coil compression spring 61 positioned around extension 65 serves tov hold the shaft 63 in spaced relation with respect to the cover plate 66.

With a view to applying an initial tension to the spring 64, the outer end of the section 65 is provided with a square shank 88 to facilitate rotation. A ratchet wheel 69 is keyed on the extension 65 and a pawl 10 cooperates with the same to hold it in place against the tension of the spring 64. In this manner by application of a wrench to the shank 68, it is possible to pretension the spring 64 as may be required.

The control of the unloading of the spring 64 to wrap the flexible conductor 60 on the spool 62 may be effected in part by a ratchet wheel 13 which may be secured, as by screws 13, to one face of the spool 62. A pawl 14, mounted on a shaft 15, Figures 1 and 5, cooperates with the ratchet wheel 13 to hold the same in any position to which it may be rotated on closure of the switch blade l6. An arm 16 is fast on the shaft 15 and it carries a roller Tl that is positioned in the path of an operating cam 18 that is carried by a contact arm 19 which is fastened to one of the blade members [8. The contact arm 19 is arranged to have contact engagement with a contact shoe 80, carried by the side plate 36 and engaged by the shaft 63, to complete the connection which includes the flexible conductor 60 to the contact 41. The arrangement of thecontact arm 19 and the contact shoe is such that, when the switch blade I6 is moved toward the open position, they are placed in contact engagement before the switch are in engagement, and that the spring 64 within the spool 82 is fully tensioned. Under these conditions, the sole connection between the switch contacts [2 and I3 is provided through the switch blade l6. Since the contact arm 19 is out of engagement with the contact shoe 88, the load break device 30 is out of the circuit. The pawl 14 holds the ratchet wheel 13 in the tensioned position so that when the switch blade I6 is moved away from the switch contact l2 and the extension 25 is moved out of engagement with the arm 54, the latter and the drum 48 remain stationary.

As the switch blade [6 is moved toward the open circuit position and while it is still in engagement with the switch contact l2, contact arm 19 engages the contact shoe 88 thereby placing the load break device 38 in parallel with the contact l2 and switch blade H5. The continued movement of the switch blade [6 toward the open position results in transferring the entire current flow through the load break device 30. Since current flow therethrough takes place only during a relatively short interval, it is unnecessary to provide a more complete interconnection between the contact 41 and the switch blade l6 than is provided by the mechanism described hereinbefore.

Continued movement of the switch blade 16 toward the open position finally causes the cam 18 to engage the roller 11 resulting in rocking of the arm 16 and shaft in a clockwise direction as viewed in Figure 1. The pawl 14 is moved out of engagement with the ratchet wheel 13 and the spring 64 is no longer restrained. It then acts to rotate the spool 62 and to wind the flexible conductor 60 thereon. In so doing the drum 48 is rotated in the direction indicated by the arrow 8 l' in Figure 5 and the flexible conductor 60 is unwound therefrom. Because ofthe length of the contact 41, it remains in contact engagement with the contact 48 for a short interval during which the drum 48 is brought substantially up to its maximum speed. Thereafter, it separates from the contact 48 and, if current was previously flowing in th circuit, an arc is drawn therebetween in the gap 50.

Initially the are between the contacts at and 41 is drawn past an aperture 82 in the frame 34 and also past additional apertures 83, 84 and 85 between the gap 58 and the aperture 82. These apertures 82 through 85 serve to vent the arc space and to divide it up and break it up so as to facilitate its extension and its extinction.

The drum 48 continues to rotate carrying with it the contact 41 and to extend the are, if it persists, between it and the contact 40. The construction is such that, under the conditions for which the apparatus is designed, the arc will be extinguished before the drum 48 is stopped. It will be understood that the drum 48 continues to rotate in the direction indicated by the arrow 8| until the arm 54 engages the rubber stop or bumper 56.

When the switch blade [8 is moved in the opposite direction to the closed position, the

contact arm 19 first engages the contact shoe 80. As a result of further movement toward the closed position, the extension 25 engages the outer end of the arm 54 to effect conjoint rotation of the drum 48 to bring the contact 41 into engagement with the contact 48. In so doing, the flexible conductor 60 is wound on the drum 48 and is unwound from the spool 62. Because of the shape of the teeth on the ratchet wheel 13 and their cooperation with the pawl 14, rotation of the spool 62 in the direction to unwind the flexible conductor 60 therefrom is permitted. At the same time the spring 64 is tensioned to effect a subsequent operation of the drum 48. While there may be a brief flow of current through the contacts 48 and 41 during the closing operation of the switch blade I6, when it is operated to the full closed position, the contact arm 19 is moved out of engagement with the contact shoe 88 and the sole connection between the switch contacts [2 and I3 is provided by the switch blade IS.

The magnitude of the arc current that can be interrupted by the load break device 38 is determined, in part, by the dimensions of the arc passageway in which it is drawn. In the embodiment of the invention illustrated in Figure 5 this passageway is indicated at 50. It is there indicated as being of substantial width. When the peripheral groove 6|, Figure 4, extends entirely around the drum 48, the arc passageway may have a relatively large cross-sectional area. In some instances, it may be desirable to reduce the size of the gap 58 where the arc is drawn so that substantially only mechanical clearance is provided between the periphery of the drum 48 and the inner surface 49 of the frame 34.

This can be accomplished by extending the peripheral groove 6! only part way around by drum 48, so that, as illustrated in Figure 6, the gap 58 between the outer periphery of the modified form of drum 48 is substantially reduced so that only mechanical clearance suflicient to permit free rotation of the drum 48 is provided. Such an arrangement will facilitate the extinction of relatively small current arcs.

Reference may now be had to Figures 7 and 8 of the drawings where a further modification of the present invention is illustrated. The housing 33 for the load break device 38 is essentially the same as described previously. A drum 88 of somewhat diiferent construction from the drum 48 is provided. As shown in Fiugre 8, the drum 88 has a peripheral groove 89 to accommodate the flexible conductor '68. In the bottom of this groove there is another groove 90 which may be connected by an aperture 9! to arcuate slot 92 in one side of the drum 88. A projection 93 carried by the side plate 83 extends into and fills the slot 12 in the same manner that a piston extends into and fills a cylinder for pumping or compressing a fluid such as air.

When the drum 88 is rotated in the direction indicated by the arrow 88 to open the circuit between the contacts 48 and 41, the air in the arcuate slot 92 is compressed as it moves relative to the projection 93. The air thus compressed moves through the apertur 9! and into the are drawn between the contacts 40 and 47. As the drum 88 continues to rotate in the opening direction, the compressed air flows through the groove 90 and out of the apertures 82 through 85. In this manner the arc is subjected to an air blast which is ei'lectiveto extend the arc and facilitate its extinction.

A vent in the form of an aperture 95 may be provided at the opposite end of the arcuate slot 92 to relieve pressure that would otherwise be developed therein when the drum 88 is rotated in the opposite direction to bring the contact 41 back into engagement with the contact 40. A cooperating vent 95 may be provided in the frame 34.

In addition to creating an air blast for assisting in extinguishing the are drawn between the contacts 40 and 4?, a cushioning effect is provided by the air pressure that is created in the arcuate slot 92. During the initial movement of the drum 88 toward the open position, this cushioning effect is at a minimum and hence there is substantially no interference with the bringing of the drum 88 up to speed. However, when the drum 88 moves through the final portion of its stroke as indicated at 96, the air pressure becomes relatively great and there is a corresponding damping effect on the further movement of the drum 88. This then reduces the shock incident to the stopping of t .e drum 88 by engagement of the arm 54 with the rubber stop or bumper 55.

If it is desired to further increase the damping action provided by the arcuate slot 92 and the cooperating projection 93, and the air blast action is not desired, the aperture 9| may be omitted or closed. The full damping action of the slot 92 and projection 93 will then be available in slowing down the rotation of the drum 88 near the end or" its stroke.

Since certain further changes can be made in the foregoing constructions 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 as described hereinbefore shall be interpreted as illustrative and not in a limited sense.

I claim as my invention:

l. For combination with a disconnecting switch having a stationar switch contact and a coopcrating movable switch blade, a load break device including a rotatable drum, drive means for said drum for rotating the same, releasable means for said drive means normally preventing operation of the same, a first contact connected to said one switch contact and extending radially toward said drum, a second contact on the periphery of said drum in engagement with said first contact when said switch blade is in the closed position, means for interconnecting said second contact and said switch blade, and means carried by said switch blade adapted upon movement of the same toward the open position to release said releasable means, whereby said drive means effects rotation of said drum to effect the final opening of the circuit through the switch between said first and second contacts.

2. For combination with a disconnecting switch having a stationary switch contact and a cooperating movable switch blade, a load break device including a rotatable drum, a first contact connected to said one switch contact, a second contact on said drum in engagement with said first contact when said switch blade is in the closed position, spring loaded drive means for said drum for rotating the same and including a flexible conductor wound on said drum and interconnecting said second contact and said switch blade, releasable means for said drive means normally preventing operation of the same and means carried by said switch blade operable upon movement of the same toward the open position to release said releasable means, whereby said drive means effects rotation of said drum to effect the final opening of the circuit through the switch between said first and second contacts.

3. For combination with a disconnecting switch having a stationary switch contact and a cooperating movable switch blade, a load break device including a rotatable drum, drive means for said drum for rotating the same, releasable means for said drive means normally preventing operation of the same, a first contact connected to said one switch contact and extending radially toward drum, a second contact on th periphery of said drum in engagement with said first contact when said switch blade is in the closed position, the outer periphery of said drum over which any arc between said first and second contacts is drawn being formed of insulatin material adapted to evolve an arc extinguishing medium due to the heat of the arc, a housing of like material in cooperative relation to said drum and forming with said periphery a restricted passageway, means including a fiexible current conducting cable wound upon said drum means and connected to said drive means for interconnecting said second contact and said switch blade, and means operable in response to movement of said switch blade toward the open position for releasing said releasable means, whereby said drive means ef fects rotation of said drum through said cable means to efiect the final opening of the circuit irough the switch betweenv said first and second contacts.

4. Switch means comprising, in combination, a rotatable drum, a pair of separable contacts one of which is carried by said drum, means for rotating said drum to separate said contacts, and damping means for decreasing the speed of rotation of said drum during the final portion of its movements in separating said contacts for reducing the shock. incident to stopping of the same comprising, an arcuate slot in the drum, a stationary closure therefor, and a projection from said closure extending into said slot.

5. For combination with a disconnecting switch having a stationary switch contact and a cooperating movable switch blade, a load break device including a rotatable drum, spring loaded drive means for said drum for rotating the same, releasable means for said drive means normally preventing operation of the same, a first contact connected to said one switch contact, a second contact on said drum in engagement with said first contact when said switch blade is in the closed position, said drive means including a flexible conductor wound on said drum and interconncting said second contact and said switch blade, means carried by said switch blade operable upon movement of the same toward the open position to release said releasable means, whereby said drive means effects rotation of said drum to effect the final opening or" a circuit through the switch between said first and second contacts, and means for said drum for rotating the same in the opposite direction to wind said flexible conductor thereon and close said contacts.

6. Switch means comprising, in combination, a rotatable drum, a pair of separable contacts one of which is carried by said drum, a rotatable spool, means for rotating said spool, a flexible conductor fixedly connected to said one contact on said drum, trained over said drum and arranged to be wound on said spool when the same is rotated to effect corresponding rotation of said drum in one direction through said flexible conductor for separating said contacts, means for said drum for rotating the same in the opposite direction to wind said flexible cable thereon and close said contacts, said drum having an arcuate slot, a stationary closure for closing said slot, and a projection extending from said closure into said slot for compressing the air therein when the drum is rotated to separate the contacts for damping its speed of rotation during the final portion of such movement and to reduce the shock incident to stopping the same.

7. Switch means comprising, in combination, a rotatable drum, a pair of separable contacts one of which is carried by said drum, a rotatable spool, means for rotating said spool, the outer Periphery of said drum over which any arc between said contacts is drawn being formed of insulating material adapted to evolve an arc extinguishing medium due to the heat of the arc, a housing of like material in cooperative relation to said drum and forming with said periphery a restricted passageway, a flexible conductor fixedly connected to said one contact on said drum, trained over said drum and arranged to be wound on said spool when the same is rotated to effect corresponding rotation of said drum in one direction through said flexible conductor for separating said contacts, means for said drum for rotating the same in the opposite direction to wind said flexible conductor thereon and close said contacts, and means comprising an arcuate slot in said drum and a fixed projection in said slot for compressing air therein to provide upon rotation of said drum for directing a blast of air through the restricted passageway to extend and assist in extinguishing the arc.

8. Switch means comprising, in combination, a rotatable drum, a pair of separable contacts one of which is carried by said drum, a rotatable spool, means for rotating said spool, the outer.

periphery of said drum over which any arc between said contacts is drawn being formed of insulating material adapted to evolve an arc extinguishing medium due to the heat of the arc, a housing of like material in cooperative relation to said drum and forming with said periphery a restricted passageway, a flexible conductor fixedly connected to said one contact on said drum, trained over said drum and arranged to be wound on said spool when the same is rotated to efiect corresponding rotation of said drum in one direction through said flexible conductor for separating said contacts, means for said drum for rotating the same in the opposite direction to wind said flexible conductor thereon and close said contacts, said drum having an arcuate slot communicating with the restricted passageway, a projection carried by said housing and extending into said slot for compressing air therein when said drum is rotated in said one direction and the same flows into said restricted passageway for extending and assisting in extinguishing the arc.

9. Switch means comprising, in combination, a rotatable drum, a pair of separable contacts one of which is carried by said drum, a rotatable spool, means for rotating said spool, the outer periphery of said drum over which any arc between said contacts is drawn being formed of insulating material adapted to evolve an are extinguishing medium due to the heat of the arc, a housing of like material in cooperative relation to said drum and forming with said periphery a restricted passageway, a flexible conductor fixedly connected to said one contact on said drum, trained over said drum and arranged to be wound on said spool when the same is rotated to effect corresponding rotation of said drum in one direction through said flexible conductor for separating said contacts, means for said drum for rotating the same in the opposite direction to wind said flexible conductor thereon and close said contacts, said drum being provided with an arcuate slot communicating with the restricted passageway, a projection extending from the housing into said slot for compressing air therein when said drum is rotated in said one direction and the same flows into said restricted passageway for extending and assisting in extinguishing the arc, the communication between said arcuate slot and said restricted passageway being such that a damping action in the movement of said drum is effected during the final portion of such movement to reduce the shock incident to stopping the same.

STANLEY C. IQILLIAN.

CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,853 Crabbs Mar. 18, 1947 470,161 Wurts Mar. 1, 1892 1,415,114 Price May 9, 1922 1,463,463 Evans July 31, 1923 2,200,122 Rawlins May '7, 1940 2,314,292 Traver Mar. 16, 1943 2,337,889 Harlow et al Dec. 28, 1943

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