US2303496A - Circuit interrupter - Google Patents

Description

Dec. 1, 1942. H. L. RAWLINS ET-AL 2,303,496

' CIRCUIT INTERRUPTER Filed Sept. 19, 1940 2 Sheets-Sheet 1 jaw/014a 0 H. L. RAWLINS ETAL CIRCUIT INTERRUPTER Filed Sept. 19, 1940 2 Sheets-Sheet 2 INVENTORS WITNESSES:

fifiefiiiii BY z/ A'ITORNEY Patented Dec. 1, 1942 OFFICE CIRCUIT INTERRUPTER Herbert L. Rawlins, Wilkinsburg, and Carl A. Ringbloom, Turtle Creek, Pa., assig'nors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 19,1940, Serial No. 357,392

14 Claims.

This invention relates generally to circuit interrupters, and more specifically to improvements in disconnecting switches.

Modern disconnecting switches, especially of the outdoor type, usually employ relatively high contact pressures at the separable contacts thereof. Because of exposure to the atmosphere, it is also preferable that the contacts have a wiping action to insure the maintenance of clean contact surfaces. Certain diificulties have been encountered in applying these features to disconnecting switches because they must be supported on relativel long insulators which have little resistance to lateral bending forces, and consequently, heretofore, relatively complex operating mechanisms have been resorted to, to obtain the required mechanical advantage, and in some instances three or more supportinginsulators have been used to obtain the desired lateral support.

One object of this invention is to provide a novel simplified form of disconnecting switch having high pressure separable contacts.

Another object of this invention is to provide novel actuating means for moving a disconnecting switch blade substantially longitudinally into and out of pressure engagement with a contact, and substantially laterally toward and away from the contact to provide a relatively large air gap in the circuit.

Another object of this invention is to provide a disconnecting switch of the type described, wherein the break contact is of a novel enclosed construction.

Another object of the invention is to provide novel separable disconnecting contacts which may be engaged upon relative movement in any of a plurality of difierent directions.

Another object of this invention is to provide in a disconnecting switch of the type described, novel means for movably supporting the disconnecting switch blade.

A further object of the invention is to provide novel arcing horn structure for a disconnecting switch of the type described.

A still further object of this invention is to provide a disconnecting switch of the type described, wherein the lateral stresses on the insulator supports are maintained low enough to permit mounting of the entire switch and operating means therefor on two supporting insulators.

These and other objects of this invention will become more apparent upon consideration of thefollowing detailed specification of a preferred embodiment thereof when taken in connection with the attached drawings, in which:

Figure 1 is a plan view of a disconnecting switch embodying my invention;

Fig. 2 is a side elevational view of the switch shown in Fig. 1 with the contact supporting housings shown in section;

Fig. 3 is a plan view of the switch shown in Figs. 1 and 2 with the contact supporting housings in section, and with the switch shown in an open position, with certain parts thereof removed;

Fig. 4 is a view similar to Fig. 3, but showing the switch in a position adjacent its closed position;

Fig. 5 is a front elevation View of the stationary contact supporting housing structure taken on substantially the line V-V of Fig. 2;

Fig. 6 is an enlarged sectional view through the stationary contact jaws taken substantially on the line VI--VI of Fig. 2; and

Fig. '7 is a schematic view showing a form of operating mechanism for the switch.

Referring to the drawings, there is shown a switch mounted on a supporting base 2. A stationary insulator 4 is secured to the base 2,'for example, as by the bolts 6, and carries at the outer end thereof a contact housing 8. The housing 8 comprises a cover plate I0 spaced from the end cap of the insulator 4 by downwardly projecting integral side wall portions l2, and the cover plate is secured in fixed relation to the insulator 4 by bolts l4 passing through the cover plate to be threadedly engaged with the end cap of the insulator. The cover plate Illis provided with a forward integral downwardly extending flange I6 and with a rear integral downwardly extending portion l8, to which is secured spaced contact jaws 29. As shown, the contact jaws 20 are in the form of elongated plate members, and are secured to the extension l8 of the cover plate by bolts 22 extending therethrough and through a terminal plate 24 disposed with one end between the contact jaw 26, to thereby space the jaws apart. The terminal plate 24 projects rearwardly beyond the contact housing 8 for connection of a line conductor thereto. The forward ends of the contact jaws 20 are connected by a tension bolt 26, having resilient cup-shaped washers 28 at the respective outer sides of the contact jaws 29 to resiliently oppose separation of these jaws.

Forwardly of the tension bolt 25, the contact jaws '29 are provided with raised limited area contacting portions 39 on the opposed inner faces of the jaws. Referring to Fig. 6, it can be seen that these limited area contact portions 30 are pressed out of the material of the contact jaws 2e, and are provided on their confronting raised surfaces with grooves 32, forming a plurality of line contacting portions adapted to engage a contact tongue when inserted therebetween. These line contacting portions extend substantially parallel to the longitudinal axis of the contact jaws 26. It will also be noted that the forward ends of the contact jaws 20 adjacent the limited area contact portions 30 have the side edges 34 thereof, and outer ends 36 bent outwardly with respect to each other to form flared entrances to the space between the contact jaws. A closure member is provided for closing the forward end of the contact housing 8, and this closure member is preferably provided with a base plate portion 38 adapted to be secured to-the end cap of the insulator 4, as, for example, by bolts 40. The closure member also includes an upwardly projecting integral flange 42 projecting upwardly in the plane of, and towards flange IS on cover plate l0, but terminating at a point spaced therefrom to provide between these flanged portions an elongated slot aligned with the space between the contact jaws 20, to permit a switch blade to enter the contact housing and into the space between the contact jaws. The flange 42, as seen in Fig. 5, is provided with an integral, upwardly projecting stop lug 43, for defining the end of the entrance slot. This lug may extend into engagement with the cover plate l8, as shown. The housing closure member may also be provided with a rear upwardly extending flange 44, if desired, for reinforcing purposes.

Also mounted on the supporting base 2 at a point spacedfrom the stationary insulator 4, is a rotatable insulator 46 having a supporting shaft 50 rotatably mounted in a bearing 48 in the base 2, The bearing48 may be secured to the base 2 in any suitable manner, such as by bolts 54. On the insulator supporting shaft 50, there is provided an actuating lever 52 secured to integral flanged portions of the shaft-for example,as by through bolts 56. A blade supporting enclosure 58 is secured to the end cap of insulator 46, for example, as by bolts 62, passing through the base plate 60 of said enclosure, to be threadedly engaged with the insulator end cap. This enclosure further includes a front wall 64 extending upwardly from and integral with the jections l8 integral with the front wall 64 of the enclosure, to thereby maintain the springs in operative position. It will be noted in connection with the spring supporting means that the front wall 64 of the enclosure 58 is provided with two spaced sets of projections 18 to accommodate a blade supporting member mounted as shown in the drawings, or mounted for movement in the opposite direction, or in other words, with the blade supporting member rotated at 180 about its longitudinal axis from theposition shown. A switch blade 80 has one end thereof secured on the outer end of the blade supporting element I0 by bolts 82, and these bolts 82 may be utilized base plate 60, and this front wall is provided with a transverse slot 68 through which a blade support 10 extends. Also integral with the front wall 64 and extending rearwardly therefrom and substantially parallel with respect to base plate 60, is a top plate 68 substantially triangular in form, and for a purpose to be hereinafter described.

Between the top plate 68 and base plate 60, there is mounted the enlarged head of a substantially T-shaped blade supporting element 10. It can be readily observed that the head portion of the blade support 10 mounted within the blade supporting enclosure, is provided with oppositely extending lateral extensions at one end thereof to form spring supporting sockets 14 at opposite sides of supporting element 10. One end of the head of support 10, is provided with a bearing portion forpivotally receiving a pivot pin I2, offset or eccentric with respect to the axis of rotation of insulator 45, and with respect to the longitudinal axis of the blade supporting member. Coil compression springs 16 are adapted to be positioned both above and below the slot in the enclosure 58 with one end of each spring seated in a socket 14 in the blade supporting head, and the other ends thereof fitting over proto clamp to the blade one end of a flexible shunt 84 of a flexible conducting material such, for example, as copper braid or the like. The other end of the flexible shunt 84 is secured to a terminal plate 88, one end of which is provided with an integral transversely extending bearing 90 adapted to receive a pivot pin 92 supported between the base plate 68 and top plate 68 of the blade supporting enclosure 58; Obviously, a line conductor 94 may be secured to the terminal plate 88 by the same bolts 86 which secure the shunt 84 thereto, and by reason of the pivotal connection 92 the terminal plate may remain stationary during rotation of the rotatable insulator 46 and blade supporting enclosure 58.

In the operation of the parts of the switch thus far described, assuming the switch to be in open position as shown in Fig. 3 of the drawings, it will be observed that the coil compression springs 16 will maintain the switch blade and its support 10 in a position where one edge thereof is in engagement with the end of slot 66 in the blade supporting enclosure. which is adjacent contact housing 8, Now if the rotatable insulator 46 is rotated by operating crank 52 in a counterclockwise direction, as viewed in Fig. 3, the insulator and parts carried thereby will be moved to the position shown in Fig. .4, with the blade entering the space between flanges l6 and 42 of the contact supporting enclosure 8, until the end of the blade comes into engagement with stop lug 43 on flange 42 of the contact enclosure. This position of the parts is shown in Fig. 4 of the drawings, and it will be noted that at this time the blade has not yet made engagement with the contact jaws 20. It will be apparent that, upon continued counterclockwise rotation of insulator 46 from the position shown in Fig. 4, the blade 80 will rotate on pivot 12 relative to the insulator 45 and will thereby be moved substantially longitudinally into the space between the contact jaws 20. The blade is preferably slightly larger in thickness than the distance between the limited area contacting portions 30 of the contact jaws, so that this longitudinal movement of the blade into engagement therewith is accompanied by a slightseparation of the contact jaws opposed by the resilient washer members 28. It will also be noted that this longitudinal movement of the switch blade is accomplished by means of a relatively great mechanical advantage. since a lever arm of the distance between pivot 12 and the axis of rotation of insulator 4B is used, instead of a lever arm equal to the length of the switch blade. It can, therefore, readily be seen that the lateral forces on the rotatable insulator when moving the blade longitudinally into pressure engagement with contact jaws 20 are substantially less than they would be if the blade were fixed withrespect to the rotatable insulator,

Another important result obtained by longitudinal movement of the switch blade into engagement with the limited area contacting portions '30 of the contact jaws is that, since the blade moves substantially parallel with the line contacting portions of the limited area contacts 30, these contacting portions may cut their own grooves in the switch blades and thereby obtain even contact throughout the length of these portions, which contact, being limited in area, will obviously be under a relatively high pressure and thereby provide an exceptionally good contact between the outer end of the switch blade and the contact jaws 20.

The fully closed position of the switch is shown in Figs. 1 and 2, and if it is desired to open the switch, it is obvious that it is merely necessary to rotate the insulator 46 in a clockwise direction from the position shown in Figs. 1 and 2, and that the first portion of this movement will cause relative rotation of the switch blade supporting member F about pivot pin 12 aided by coil compression springs 76, and this will act to withdraw the outer end of the switch blade substantially longitudinally from between the contact jaws 20 until the parts reach the position shown in Fig. 4 of the drawings. At this point, the switch blade has been withdrawn from the plane of contact jaws 20 and is able to engage with the adjacent end of slot 66 in the blade supporting housing, whereby continued rotation in a clockwise direction from the position shown in Fig. 4 will cause positive pivotal movement of the switch blade with insulator 46, and thereby move the blade out of the contact supporting enclosure 8 to a position such as that shown in Fig. 3, to insert a relatively large air gap in the circuit.

It is believed obvious from the foregoing that the switch blade has two distinct successive movements in both its opening and closing operations. In other words, in closing, the blade first moves pivotally into proximity to the stationary contact jaws 2H, and thereafter is moved substantially longitudinally into pressure engagement between these jaws. On opening the switch, the reverse sequence of movements takes place; that is, the blade is first withdrawn substantially longitudina-lly from intimate engagement with contact jaws 2B, and is thereafter pivotally moved to a position away from the contact jaws to provide a relatively wide air gap in the circuit.

Referring to Fig. 5, it will be noted that both the flange It on the top wall of contact enclosure 8 and flange 42 are provided with inclined relatively outwardly flaring edge portions 98 and 96, respectively, to guide the switch blade into the space between these flanges and align th same in a position to enter between the contact jaws 20, It is also to be noted that the slot provided between flanges IB and 42 of the contact enclosure 8 at the open end thereof extends along one side of the limited area contact portions 38 of the contact jaws, so that in the event the switch blade is not, for any reason, maintained by coil springs I6 relative to the blade supporting enclosure in the position shown in Figs. 3 and 4, the switch can still be closed, since the blade may enter between the contact jaws Zil from one side thereof due to the wide opening in the contact housing and aided by reason of the outwardly bent side edges 34 of the contact laws 28. This might oc-- cur upon failure of coil springs I6, or if for some other reason the blade supporting enclosure became filled with a solid mass of dirt or debris, preventing relative pivotal movement of the blade supporting enclosure and of the blade proper.

"It should also be noted that but a single flexible shunt 84 is provided for bridging both pivots 92 and 12 between the switch blade and terminal plate 88. Switch blades which have been constructed heretofore capable of moving with a compound movement in their opening and closing operations have necessitated, as stated before, relatively complex structures embodying many pivotal connections which necessitate a plurality of shunts for bridging these connections. The particular arrangement of applicants blade mounting, especially of the two pivots referred to above, readily permits simplification of such an arrangement by the use of a single shunt 84.

Arcing horns I09 and IE2 are provided to be secured to the blade and contact housing 8, repectively, and are of a novel type to permit the compound movement of applicants switch blade in its opening and closing operations. As shown especially in Figs. 1 and 2, the arc horn I61] includes a loop portion I04 adapted to be secured to the switch blade 80 at an intermediate portion thereof by a clamping plate I96 and bolts I 68. The arcing horn I00 from the loop portion I04 has an inclined portion I'll] extending upwardly, and a contacting portion II2 extending from the inclined portion substantially parallel with respect to the switch blade 80 and its path of movement,

and an outer end portion II4 bent substantially reversely with respect to the contacting portion II2 thereof. The are horn IOZ is also provided with a loop portion IIB positioned within a plu rality of positioning lugs H9 provided on the upper outer surface of the contact housing 8 and secured thereto, as, for example, by a bolt H8. From the loop portion M6, the arc horn I82 extends substantially vertically as at I20, and then horizontally to form a contacting portion which is in a plane parallel to the switch blade and the contacting portion H2 of the arcing horn I 60, but at an angle to th direction of movement of the switch blade and arcing horn I00. The outer end of the arcing horn IE2 is extended substantially vertically as at I24.

It can readily be seen that when the switch is opened, or moved from the closed position shown ment during longitudinal movement of the switch blad out of engagement with contact jaws 20, and during the first part of the subsequent pivotal movement of the blade, and that these portions of the arc horns will become disengaged only after the switch blade 80 is moved out of engagement with contact jaws 20, and even away from the plane of the contact supporting housing 8. The are horns I00 and H12 are preferably made of some conducting material which is resilient such, for example, as a copper alloy. Upon closing the switch, the inclined end of arc horn I00 formed by the reverse loop IM will first engage with the contacting portion I22 of arc horn I02, and by a camming action will be slightly stressed so that the contacting portions of the arc horns will be maintained in engagement under some resilient stress.

It will be observed that when the switch is closed, the coil springs I6 have some tendency to open the switch by virtue of the fact that when the switch is closed these springs are compressed, and hence when the switch is in a fully closed position, the springs, as viewed in Fig. 1, bias the blade supporting enclosure 58 and blade support II! in opposite directions for relative movement about the pivot pin 12.. Obviously, such movement mightcause. longitudinal withdrawal of the end of the switch blade from between contact jaws 20. Although these springs I6 are preferably not very strong, since it is only necessary that they be strong enough to move the switch blade into engagement with one end of slot 66 when the switch is opened, nevertheless, to prevent the possibility of these springs from causing disengagement of the switch, an operating mechanism for the switch, such as shown in Fig. 7, may be employed. The mechanism shown in Fig. 7 includes a link I26 pivotally connecting to the operating crank 52 of the rotatable insulator at one end thereof, and having its other end pivotally connected to an intermediate portion of an operating lever I28. The operating lever I28 is pivoted at one end I3I on a fixed support I30, and in the closed position of the switch is in engagement with a fixed stop I32. Obviously, if the operating lever I28 be moved in the direction of the arrow shown in Fig. 7, the connecting link I26 will be moved over the center of pivot I3I and the switch opened. In closing, the reverse movement of the operating lever takes place, and when link I26 moves from below pivot I3I to above this pivot, as shown in Fig. '7, it obviously passes over center and any force inherent in the switch blade to open itself is obviously prevented, because the operating handle I28 is in engagement with stop I32 and cannot move in a direction towards the switch. Movement of the operating link I26 over the center of pivot I3I is permitted by a certain amount of play in the connections of the links and levers. While the particular mechanism illustrated in Fig. 7 is relatively simple and particularly adapted for operating disconnecting switches of this type, it is obvious that other types of mechanism embodying some sort of locking means, when the switch is in its fully closed position, could be used.

From the foregoing it should be apparent that the interrupter disclosed above in the form of a disconnecting switch provides relatively simple means for obtaining compound movement of the switch blade with a relatively great mechanical advantage. This invention also comprehends the particular arrangement of limited area line contact portions which are engaged or disengaged by a contact movable substantially in the direction of the line contacts. There has also been disclosed novel forms of arcing horns especially adapted for switches of the type wherein the switch blade is provided with a compound motion in its opening and closing operations. The entire switch structure, taken as a whole, is obviously of simplified form, while at the same time it is of a sturdy construction. The fixed contact of the switch is entirely enclosed in a housing in a novel manner, as are the movable supporting portions of the switch blade. This not only provides for an extremely neat-appearing switch, but one which is also extremely practical in that access of the elements and debris to moving or contacting parts of the switch is thereby precluded.

Having described preferred embodiments of the invention in accordance with the patent statutes,

it is desired that the invention be not limited to the particular embodiments disclosed herein, inasmuch as it will be obvious particularly to persons skilled in the art that many changes and modifications may be made in this particular structure without departing from the broad spirit and scope of the invention. Therefore, it is desired that the invention be interpreted as broadly as possible, and that it be limited only by what is expressly stated in the following claims and by the prior art.

We claim as our invention:

1. In a circuit interrupter, hollow movable contact supporting and actuating means, an opening in said means, contact means extending through said opening and movably mounted in said supporting means for movement relative thereto and limited by opposite ends of said opening, terminal means also extending into said supporting member and movably mounted therein, and a single flexible shunt means connecting said terminal and contact means, for spanning said movable mountings.

2. Circuit interrupting means including a rotatable insulator carrying a hollow blade supporting means, blade means pivotally mounted in said supporting means on an axis eccentric with respect to the'axis of rotation oi said insulator and extending through an opening in said hollow supporting means, a second insulator carrying hollow contact supporting means, contact means therein, an opening in said contact supporting means for receiving the outer end of said blade means in its pivotal movement with said rotatable insulator, one end of said opening in said contact supporting means constituting a stop for said blade means in its closing movement, whereby continued movement of said rotatable insulator in the same direction causes relative substantially longitudinal movement of said blade means into intimate engagement with said contact means, arcing horns mounted on said blade means and contact supporting means,

' respectively, andincluding elongated engageable portions positioned in a plane spaced from but substantially parallel to the plane of movement of said blade and disposed at different angles, respectively, with respect to the direction of movement of said blade means with said rotatable insulator, whereby said horns remain in engagement during said longitudinal movement, and engage or disengage only during said pivotal movement of said blade means.

3. In a circuit interrupter, contacts at least one of which is movable into and out of intimate engagement with the other substantially rectilinearly, and being substantially laterally movable from a remote position to a position in proximity thereto, arcing horns mounted on said contacts, respectively, and including elongated engageable portions in a plane spaced from but substantially parallel to the plane of movement of said movable contact, and disposed at different angle with respect to said lateral direction of movement of said movable contact, whereby said arcing horns remain in engagement during said rectilinear movement, and are engaged or disengaged during said lateral movement.

4. Circuit interrupting means including a contact movable into and out of engagement with rality of raised substantially parallel line contacting portions extending substantially in the direction of said rectilinear movement for engagement with said movable contact.

5. Circuit interrupting means including a contact movable into and out of engagement with a cooperating contact, stop means adjacent said cooperating contact, rotatable supporting and actuating means for said movable contact, said movable contact being eccentrically movably mounted on said supporting means for movement therewith into and out of engagement with said stop means and for limited relative movement thereto substantially rectilinearly into and out of engagement with said cooperating contact, and one of said contacts including a, plurality of spaced substantially parallel line contacting por-v tions extending in the direction of said rectilinear movement for engagement with at least one side of the other of said contacts.

6. In a disconnecting switch, a switch blade, rotatable supporting and actuating means for said blade comprising spaced supporting plates for pivotally mounting said blade therebetween, a side plate connecting said spaced plates for maintaining them in spaced relation, and said side plate having an elogated slot therethrough for receiving an intermediate portion of said blade to permit pivotal movement thereof limited to the extent of said slot.

7. In a disconnecting switch, a switch blade, rotatable supporting and actuating means for said blade comprising spaced supporting plates for pivotally mounting said blade therebetween, a side plate connecting said spaced plates for maintaining them in spaced relation, said side side plate having an elongated slot therethrough for receiving an intermediate portion of said blade to permit pivotal movement thereof limited to the extent of said slot, and the space between said spaced plates being otherwise open so that one end of a terminal member may also extend into the space between said plates so as to be pivotally mounted therebetween.

8. In a disconnecting switch, a switch blade, rotatable supporting and actuating means for said blade comprising spaced supporting plates for pivotally mounting said blade therebetween, a side plate connecting said spaced plates for maintaining them in spaced relation, said side plate having an elongated slot therethrough for receiving an intermediate portion of said blade to permit pivotal movement thereof limited to me extent of said slot, the space between said spaced plates being otherwise open so that one 1 end of a terminal member may also extend into the space between said plates so as to be pivotally mounted therebetween on an axis coinciding with the axis of rotation of said supporting and actuating means, and the pivot axis of said blade being offset from the pivot axis of said terminal member and supporting and actuating means.

9. In a circuit interrupter, contacts at least one of which is movable into and out of intimate engagement with the other, arcing horns mounted on said contacts, respectively, and including elongated engageable portions in a plane spaced from but substantially parallel to the plane of movement of said movable contact, and disposed at different angles with respect to the direction of movement of said movable contact, whereby said arcing horns are engaged or disengaged only when said contacts are disengaged.

10. In a circuit interrupter, rotatable insulating means, h'ollow mounting means on said rotatable insulating means, a 'slot through one wall of said mounting means, a generally T- shaped blade member including a blade portion smaller than said slot and extending therethrough and a cross head portion in said mounting means, and one end of said cross head portion pivotally mounted in said mounting means on an axis eccentric relative to the axis of said insulating means.

11. In a circuit interrupter, rotatable insulating means, hollow mounting means on said rotatable insulating means, a slot through one wall of said mounting means, a generally T- shaped blade member including a blade portion smaller than said slot and extending therethrough and a cross head portion of greater extent than said slot and located in said mounting means, and said cross head portion pivotally mounted in said mounting means on an axis eccentric relative to the axis of said insulating means.

12. In a circuit interrupter, rotatable insulating means, hollow mounting means on said rotatable insulating means, a slot through one wall of said mounting means, a generally T- shaped blade member including a blade portion smaller than said slot and extending therethrough and a cross head portion in said mounting means, and one end of said cross head portion pivotally mounted in said mounting means beyond one end of said slot on an axis eccentric relative to the axis of said insulating means, whereby the other end of said cross head portion is adapted to engage said mounting means adjacent the other end of said slot for limiting relative movement of said blade member in one direction.

13. In a disconnecting switch, a switch blade rotatable supporting and actuating means for said blade comprising spaced supporting plates for pivotally mounting said blade therebetween, a side plate connecting said spaced plates for maintaining them in spaced relation, said side plate having an elongated slot therethrough for receiving an intermediate portion of said blade to permit pivotal movement thereof limited to the extent of said slot, and the space between said spaced plates being open at least at the side opposite said side plate so that one end of a terminal member may extend into the space between said plates at said opposite side thereof, and means pivotally mounting said one end of said terminal member between said plates.

14. In a disconnecting switch, a rotatable insulating support, a switch blade and a terminal member pivotally mounted on said support on difierent pivot axes for movement relative thereto and each other, a single flexible shunt means electrically connecting said blade and terminal member and spanning said pivots, and means limiting relative pivotal movement of said blade and support.

HERBERT L. RAWLINS. CARL A. RINGBLOOM.

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