US1968869A - Electric switch - Google Patents

Description

A. O. AUSTIN ELECTRIC SWITCH- Aug. 7, 1934.

Filed July 7, 1931 4 Sheets-Sheet 1 INVENTOR flIFT'f/UE 0. flusrx/y a Armada! Mpg Aug. 7, 1934. A, Q AUSTIN v 1,968,869

ELECTRIC SWITCH Filed July 7. 1931 4 Sheets-Sheet 2 INVENTOR Ari/7w Q Ausfi/z ATTO Aug. 7, 1934.

A. O. AUSTIN ELECTRIC SWITCH Filed July 7, 1931 4 Sheets-Sheet 3 w Mg INVENTOR {45mm 0. Al/S-Tl/Y B Aug. 7, 1934. o, s m 1,968,869

ELECTRIC SWITCH Filed July 7. 1931 4 Sheets-Sheet 4 INVENTOR Arf/iur 0. Ausf/n BY- f k Patented Aug. 7, 1934 UNITED srsrss ELECTRIC swrrcn thur 0. Austin, near Barbcrtcn, Ohio, assignor, by mesne assignments, to The Ohio Brass Company, Mansfield, Ohio, a

Jersey corporation of New Application July 7, 1931, Serial o. 549,221

Claims.

This invention relates to switches for electric currents and has for one of its objects to provide an electric switch having improved electrical contacts at the switch connections.

A further object is to provide a switch which 5 will carry heavy electric currents without undue heating.

A further object is to provide a switch in which-heavy currents will not open the switch l or break the electrical connection.

A further object is to provide a switch which shall be of improved construction and convenient and reliable in operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a vertical sectional view of a portion of a switch showing one embodiment of the present invention.

Fig. 2 is a section on line 2--2 of Fig. 1.

Fig. 3 is a view similar to Fig. 1 showing a somewhat modified form of switch.

Fig. 4 is a section on line 44 of Fig. 3.

Fig. 5 is a view similar to Fig. 1 showing the '1 invention applied to a rectangular bus bar.

Fig. 6 is a section on line 6-6 of Fig. 5.

Fig; 7 is a fragmentary section showing another form of the invention.

Fig. '8 is a section on line 8-8 of Fig. '7.

. Fig. 9 is a view similar to Fig. '7 showing another modification.

Fig. 10 is a section on line 1010 of Fig. 9. In disconnecting switches used for heavy currents, it is frequently difficult to provide a Lswitch of ample current carrying capacity which will operate satisfactorily over long periods of time. In switches as heretofore constructed, the resistance of the contact between switch points frequently increases to such an extent that the switch becomes overheated. In many switches considerable space is required for the operating mechanism and in some types, it is difficult to segregate the different phases of a polyphase circuit because of the operating mechanism.

'In the present invention the usual difiiculties or limitations are largely or entirely removed, resulting in an improved type of disconnecting switch. The general features of the switch are applicable not only to the lower voltages but to very high voltages as well. The invention, however, has'its principal advantages where heavy contacts are desired and where it is'desirable to avoid undue strain upon the supporting insulators. The present invention also provides a construction in .which short circuits will not tend to cause the switch to open, which tendency is frequently serious in the case of knife switches. 5

In the form .ofthe .invention shown in Fig. 1, tubular bus conductors 10 and 11 are mounted on insulators l2 and 13 by switch terminals 14 and 15, whichterminals are clamped to the ends of the bus bars by clamping bolts 16. The terminals 14: and 15 are electrically connected when the switch is closed, as shown in the drawings, by a switch blade or plunger 17 mounted to slide in the bus 10 and to enter the end of the bus 11. Spiders 18 and 19 are secured to the interior of the blade 17 in spaced relation to each other,'and a shaft 20 extends freely through central openings in the spiders. The rear end of the shaft 20 is threaded at 21 into the end of a'ra'ck 22 which is driven by a pinion 23 mounted on a shaft 24, which shaft also carries a gear 25. The gear 25 is .driven by a pinion 26 mounted on a shaft 27, the shaft 27 being connected through an insulating coupling with any suitable. driving mechanism. The drive may be either manual or motor operated and is usually located at a distance from the switch and may be outside of the bus compartment. If the switch is motor driven, the motor may be provided with any suitable form of remote control, if desired. 'A. support 28 is fixed to the shaft 20 adjacent the end of the rack 22 and is slideably supported in the interior of the switch blade 17. A wedge 'block 29 freely surrounds the shaft 20 in front of the support 28 and is urged forwardly by a spring 30 which bears against the rear of the block 29 and abuts against the support 28. The forwardmovement of the wedge block 29 is limited by a collar 31 fixed to the shaft 20 and a spacing sleeve 32 interposed between the collar 31 and the wedge block 29. A carrier 33 is provided with forwardly extending arms 34 guided in channels 35 at .the corners of the wedge block 29. Rollers 36 are journaled between the arms 34 and mounted to travel on the inclined faces 37 of the'wedge block 29. The carrier 33 is pressed forwardly by a spring 38 of less strength than the spring 30. Complementary wedging blocks 39 are secured to the interior of the switch blade 17 in registration with. the respective of the respective wedging blocks.

wedging faces of the block 29 so that the adjacent faces of the cooperating wedging blocks are substantially parallel and engage opposite portions of the rollers 36.

It will be seen that if the block 29 is moved forwardly while the switch 17 is stationary, the rollers 36 would exert an outward force on the blocks 39, tending to spread the switch blade 17. The blade 17 is provided with slots '40 of limited length to permit the blade to be expanded into close electrical contact with the interior of the bus bar 10 within the switch terminal 14. When the wedge block 29 is moved forward, the rollers 36 will travel on .the respective complementary faces so that the carrier 33 will move forwardly only half as fast as the wedge block 29. The spring 38 will thus be compressed to permit of the differential movement between the carrier 33 and the wedge block 29.

Forward movement to close the switch'blade 17 is imparted to the-blade from the rack 22 and shaft 20 by means of a spring 41 which bears against the spider 19 and against the collar 31 on the shaft 20. A spacer sleeve 42 also bears against :the collar 31 and against a bearing disk 43. The disk 43 engages springs 44 and 45, similar to springs 30 and 38 respectively, which operate a forward wedging block 46'similar to the-block'29. The wedging block 46 cooperates with a carrier 47, rollers 48 and complementary wedging blocks 49 for spreading the forward end of the switch blade within the terminal 15in a manner similar to the operation of the block 29 in the terminal 14. A pair of limiting rods 50 are fixed to the spider 18 at their forward ends and are disposed at opposite sides-of the rack 22 and have sliding connection with a stop 51 secured-to the bus :bar 10.

When it is desired to close the switch, the pinion 23- is rotated to'move the rack 22 forwardly which operates through the spring 41 and spider 19 to move the blade 1'7 across the gap between the terminals 14 and 15 and project the end of the blade into the interior of thebus bar 11 within the terminal 15. The blade is guided into position-by a conical mouth 52 in the terminal'15. The'rods 50 will be carried forwardly until the nuts 53 on-the ends of the rod are arrested by the stop 51 which will, in turn, arrest the forward movement of the spider 18 and the switch blade 17. As the rack 22 continues to move forwardly, the spring 41 may be compressed, permitting the shaft 20 to' continue to travel after the-arrest of theblade 17. The forward movement of the shaft 20 will compress the springs 30 and 44 and force the wedging blocks 29 and 46 between the wedging blocks 39 and 49 respectively, secured to the interior of the blade '17. The springs 38 and 45 will permit differential movement of the roller carriers and their'respective wedging blocks so that the rollers will have rolling connection at their opposite sides with the cooperating faces The wedging movement will expand the blade within the respective switch terminals so as to produce electrical connection between the blade and terminals without producing any stress upon the supporting insulators 12 and 13.

In the modification shown in'Figs. 3 and 4, the rack 22 is replaced by a hollow externally threaded shaft 55 which is operated by a worm drive 56 and '57, the wheel 57 being provided with internal threads meshing with the threads '18 in Fig. 1.

on the shaft 55. The shaft 55 is held from ro- .tation by a key 58. A stop rod or bar 59 extends through the center of the shaft 55 and is provided with a stop plate 60 arranged to engage a fixed boss 61. The forward end of the stop rod 59 is connected to a spider 62 by means of a bar 63. The spider 62 is fixed to the blade 17 in a manner similar to the spider The shaft 55 is fixed to the shaft 20 by a yoke 64 which straddles the block 63. The wedging block 65 is conical in shape instead of rectangular and the corresponding wedging blocks 66 form a cooperating surface concentric with the surface of the block 65. Ball bearings 67 are interposed between the wedging members-65 and 66 and are held by a ball retainer 68 mounted on the carrier 69. The

operation "of the invention in Figs. 3 and 4 is similar -:to :that in Figs. 1 and 2 except that the worm drive provides a positive lock for the switch blade, and the roller bearings between the wedging members are in the form of balls instead of cylindrical'rollers and travel on conical rather than-plain surfaces.

Figs. 5 and 6 show a form'of the invention adapted for rectangular -bus bars instead of cylindrical bars, as shown in Figs. 1 to "4 inelusive. As shown-in Figs. 5 and :6 the terminals YO-and 7-1 are rectangular in shape inorder to receive the plates 72 and 73 which form the rectangular bus bars. The other construction is like that of Figs. land 2 except that the outer wedging members 74 have plain outer faces instead of curved faces, as in Figs. 1 and 2. Rollers 76 and 77 are mounted inthe lower portions of the terminals and 71 respectively to support the switch as it moves into-open and closed position, and thus prevent the switch blade from dragging in the terminals. Pin type insulators 78 may .be used for supporting the switch terminals instead of the post type insulators, shown in Figs. 1 and'3. The rollers 76 and 77 are spring held against the switch blade so as to yield and permit expansion of the blade under the wedging action of the rollers 36.

In the form of the invention shown in-Figs. 1, 2, 5 and 6 the springrollers insure contact at all sides of the switch blade. If one pair of rollers opposite each other come into contact L flexibility is provided to insure pressure on all four sides of the switch contact.

Compensating means is also provided for insuring good electrical connection at both ends of the switch blade with the respective switch terminals. If the wedging connection with one terminal comes into operation first, the operating rod 20 is not brought to a positive stop but the spring interposed between the wedge block and the rod provides leeway to permit sufiicient additional movement of the rod tobring the other wedging block into operation. When the switch is finally closed, both wedging blocks are held inposition by spring action, thus insuring good electrical connection with both switch terminals.

If there were no com- In the form of the invention shown in Figs. 7 and 8, instead of relying upon spring rollers to compensate for inequalities in the operation of the two pairs of wedging rollers, each pair of rollers is separately actuated. In this construction the bus bar is formed of angles disposed at opposite corners of a square tubular member and the switch blade is also formed of a plurality of angle bars 81 which fit into the respective angle bars 80. Angle blocks 82 are secured to the inner sides of the angle bars 81 in position to register with the respective terminal members 83 when the switch is in closed position. The blocks 82 are each provided with inner inclined surfaces 84 and the angle bars 81 are so mounted on their spiders 85 and 85 that they can be moved outwardly a sufficient amount to insure firm pressure between the outer surfaces of the bars 81 and the inner surfaces of the bars 80. The pairs of oppositely disposed blocks 82 are provided with wedging members 87 and 88 respectively. The horizontal wedging member 88 is provided with braces or arms 89 which extend through the wedging member 8'7 but are free from contact therewith so that the respective wedging members 8'7 and 88 are free to move longitudinally of the switch independently of each other. The wedging member 87 is pressed forwardly by springs 90 while the wedging member 88 is pressed forwardly by a separate pair of springs 91. The springs 90 and 91 are all moved by the supporting slide 92 which is secured to the operating shaft 20, in the same manner as the slide 28 in Fig. 5. The independent spring operation of the two wedging members insures firm engagement of all of the angle blocks 82 with their respective angle blocks forming the plate of the switch. Rollers 93 are interposed between the wedging members and angle blocks and are held in place by retainers 94, each of which is urged forward by a spring 95 of considerably less strength than the springs 90 so as to provide for differential movement between the rollers and the respective wedging members.

In the modification shown in Figs. 9 and 10, the bus bars are formed of channel bars 96 arranged opposite each other and the switch blades are also formed of channel bars 9'? arranged to fit within the channel bars 96. Wedging blocks 98 are secured to the inner face of the switch bars 97 and a single wedge member 99 provided with opposite wedging faces cooperating with the rollers 106 to force the channel bars outwardly into good electrical contact with the bus bars 96. In this case it is unnecessary to compensate for oppositely disposed pairs of wedging rollers because only a single pair is necessary for each switch terminal.

I claim:

1. An electric switch comprising a contact member, a pair of wedging members for operating said contact member, rollers interposed between said wedging members, a holder for said rollers, and a yielding connection between said holder and said wedging members to permit relative movement of said holder relative to said wedging members when said rollers travel on said wedging members.

2. A heavy current electric switch comprising spaced terminals each having a blade opening therein, a blade for spanning the space between said terminals, a drive for moving said blade into position to engage both of said terminals, means other than said terminals for arresting said blade at the limit of its movement, a spring interposed between said blade and said drive to permit further movement of said drive after the arrest of said blade, a pair of separately movable devices actuated by said drive during the movement thereof subsequent to the arrest of said blade for pressing said blade into close contact with the respective terminals, and springs interposed, one between said drive and each of said separate devices, respectively for permitting independent movement of said separate devices by said drive.

3. A switch comprising spaced terminals each having a blade opening therein, an expansible blade for bridging the space between said openings, a self-locking worm drive for moving said blade into position to engage both of said terminals, a spring interposed between said drive and said blade for permitting extra movement of said drive after said blade has reached its limit of movement, separate wedging devices actuated by said drive, during said extra movement, for expanding said blade in said openings respectively, and springs interposed between said drive and said wedging devices respectively for permitting independent operation of said wedging devices to insure good electrical contact between said blade and each of said terminal members.

4. A switch comprising spaced terminals each having a blade opening therein, an expansible blade for bridging the space between said openings, a self-locking worm drive for moving said blade into position to engage both of said terminals, a spring interposed between said drive and said blade for permitting extra movement of said drive after said blade has reached its limit of movement, wedging devices actuated by said drive during said extra movement for expanding said blade in said openings respectively, springs interposed between said drive and said wedging devices respectively for permitting independent operation of said wedging devices to insure good electrical contact between said blade and each of said terminal members, rollers interposed between each of said wedging devices and said blade, and springs for moving said rollers in unison with said wedging devices into operative position but permitting movement of said rollers relative to said wedging devices during operation of said wedging devices.

5. The combination with a pair of electric switch terminals, of a blade for connecting said terminals, a drive for moving said blade into cooperative relation with both of said terminals, separate devices actuated by said drive for expanding said blade to make close contact with each of said terminals respectively, and spring connection between each of said devices and said drive for effecting operation of said devices independently of each other.

ARTHUR O. AUSTIN.

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