US2879348A - By-pass switch - Google Patents

Description

. March '24, 1959 r. B. ORTWIG BY-PASS SWITCH 5 Sheets-Sheet 1 Filed F'eb. 21. 1957 M h 24, 1959 'r. B.-ORTWIG 2,879,348

' BY-PASS SWITCH Filed Feb. 21, 1957 s Sheets-Sheet 2 connects the auxiliary equipment from the circuit.

United States Patent BY-PASS SWITCH Thomas B. Ortwig, Florissant, Mo., assignor to James R.

Kearney Corporation, St. Louis, Mo., a corporation of Missouri Application February 21, 1957, Serial No. 641,524

Claims. (01. 200-50 This invention concerns by-pass switches and constitutes an improvement over the switch disclosed in the copend- I are designed to allow the temporary by-passing of electric equipment such as, for example, a voltage regulator,

by providing a mechanism which closes a bridging circuit across the voltage regulator or other auxiliary equipment simultaneously with the opening of the switch which dis- The present improvement consists mainly in an improved switch arm, by-pass contact structure and operating mechanism, which together allow the adaptation of this type of switch to circuits carrying high currents and subjected to high voltages.

More particularly, the main switch arms of the switch of this application are provided with a mechanically loadbearing reinforcing member and a resilient switch blade suspension designed to allow the switch blades to freely adapt themselves to wear of the switch contacts without interference from the mechanical strain caused by the by-pass switch operating linkage.

The linkage itself has been improved in the device of this application to provide faster and more positive action and to be less subject to failure from misadjustment of the mechanical parts.

Finally,.the design of the by-pass switch structure itself has been improved by providing a bridging member equipped with several independently movable contact heads which are particularly designed to maintain an optimum contact area with the fixed by-pass contacts regardless of uneven wear of the by-pass contacts.

It is therefore an object of this invention to provide a by-pass switch assembly adapted for use on high current, high voltage circuits, and which provides quick positive switching action and a minimum possibility of mechanical failure.

I will now describe my invention with respect to the attached drawings in which:

Figure 1 is an over-all elevation of the device of my invention;

Figure 2 is a plan view thereof;

Figure 3 is a detail elevation, partially in section, along lines 3-3 of Figure 4, showing the improved bridging member and its operating mechanism; and

Figure 4 is a plan'view of the bridging member and its operating mechanism.

The preferred embodiment of the device of my inven- 2,879,348 Patented Mar. 24, 1959 tion described herein generally comprises a pair of main switch arms, each composed of two switch blades and a reinforcing member, which normally carry electric current from a power line to such auxiliary equipment as may be desired, when the main switch arms are in the closed position. One of the main switch arms is provided with an eye adapted to be engaged by a standard switch stick. Means are provided for normally locking the main switch arms in the closed position, but releasing the lock when a switch stick is applied to the eye for opening the main switch arms. The two main switch arms are rigidly tied together by an insulator so that they will move in unison. A rigid structure for the main switch arms is provided by special reinforcing members which bear the actual mechanical load involved in the opening and closing of the main switch arms. These reinforcing members are provided with arm-like extensions which support the actual switch blades. The switch blades are so arranged on these supporting arms as to have some liberty of individual movement so as to be able to adapt themselves to wear of the main switch contacts. The reinforcing member on the side where the switch stick eye is located also supports a rigidly mounted lever which engages a cam forming part of the bridging member operating mechanism. This cam is mounted in fixed bearings and is so shaped as to cause rapid movement of the bridging mem ber assembly into bridging position at the beginning of the opening motion of the main switch arms. Provision is also made in the shape of the cam for a tendency of the cam assembly to lock the bridging member by detent action in the fully closed position, whereby the bridging member is secured against opening due to vibrations or jarring, and the extra force which has to be applied in order to overcome the detent accounts for even faster movement of the bridging member on the opening stroke.

The bridging member itself consists of a spring-loaded platform which supplies the main pressure of the bridging heads against the inclined contact surfaces of the fixed by-pass contacts. In addition, each bridging head is mounted on the platform with the aid of separate springs so as to be capable of limited individual movement. This feature provides for a perfect seating of all the bridging heads even though the fixed by-pass contacts may change their shape due to mechanical wear or arcing.

Referring now to Figure 1, the switch of my invention is shown to be mounted on a base 10 which is normally affixed to a suitable vertical support in any desired manner. The energized portions of the switch structure are insulated from the base 10 by insulators 12. Electrical leads are brought to the switch at four terminals generally designated by 14, the power line being connected to terminals 16 and 18 and the auxiliary equipment being connected to terminals 20 and 22. All of the terminals 14 are provided with appropriate apertures 24 adapted to receive such clamps or bolts as may be necessary for the proper attaching of the leads. A pair of by-pass contacts 26 are bolted directly to the terminals 16 and 18. The contacts 26 may be formed of copper and are provided with an inclined contact face 28 which is adapted to engage the bridging heads 30. A pair of main switch contacts 32 and 34 are mounted on the terminals 18 and 16 respectively, the contact 34 being provided with a flange 36 adapted to engage a spring-loaded hook 38 when the main switch arms are in the fully closed position. An eye 40 adapted to en 3. gag stan a d switch stick and attached to main switch arm 46 by bolt 64 is connected to the hook 38 so as to disengage it when the eye 40 is moved toward the left in Figure 1. An arm 42 is also connected to the hook 38 and bolt 64 and engages the top of contact 34 in such a manner as to push the hook 38 into engagement with the flange 36 when the main switch arms attain their fully closed position. Each of the main switch arms 44 and 46 are composed of a .rigid reinforcing member 48 mounted on a stationary hinge 50 and rigidly tied to the other reinforcing member 48 by an insulator 52. Each reinforcing member 48 is provided with a series of rigidly mounted supporting arms 54. A pair of switch blades 56 are slipped over the hinge 50 and the supporting arms 54. The apertures in the switch blades 56 through which the hinge 50 and the supporting arms 54 pass are made somewhat larger than the diameter of the hinge and supporting arms, so that the switch blades 56 have a small amount of play. The switch blades are maintained at a minimum spacing by spacers 58, but their spacing can i be increased against the spring action of spring washers 60, the amount of resiliency of the spring washers 6% being adjustable .by means of lock nuts 62. The lateral faces of contacts 32 and 34 are slightly slanted, so that they tend to spread the switch blades 56 against the spring action of the washers 60 when the switch members 44 and 46 are pulled into the fully closed position. The switch stick eye assembly 38, 40, 42 is journalled on supporting arm 64 so as to exert no mechanical stress on the switch blades of switch arm 46, but only on the reinforcing members 48.

The reinforcing member 48.of switch arm 46 supports an operating lever '66 which is rigidly attached to the member 48 by mounting bracket 68. The horizontal position in Figure l of lever 66 can be adjusted by a nut 70. Lever 66 isproyided at its lower end with a finger 72 which engages a track 74 of a cam member 76 journalled in a fixed bearing 78. The cam member ,76 is providednear its opposite face with a second track 80 which is engaged by an operating rod 82. The left end in Figure 1 of .the track 80 is provided with a square extension 84, the purpose of which is to permit a detent action which locks the operating rod 82 when it reaches the left end of the track 80. The operating rod 82 is rigidly connected to a bracket 86 on which a platform 88 is resiliently mounted through the intermediary of compression spring 90. The bracket 86 is supported by a pair of sliding bearings 92 supported by a fixed supporting structure 94.

Referring now to Figure 4, the platform 88 supports a number of bridging heads 30 which are tied together .by a shaft 101, fixed with respect to platform 88 by supporting member 99, which is inserted through the heads .30. without substantial play, and shaftsliltl which are .also .mounted on member 99.but are substantially smaller than the bores of the heads 30 through which they are placed, thus allowing limited relative movement of the heads 30 with respect to each other. ,Each of the heads 30 is individually mounted for floating suspension on the platform 88 by means ofsprings 102.

In operation, when it is desired to disconnect the auxiliary equipment from the circuit and to by-pass it by means of the switch of my invention, the head of a :standard switch stick is inserted in the eye 40 of the main switch members and pressure is exerted on the .eye toward the left in Figure 1. This releases hook 38 -and permits movement of the switch arms 44 and 46 to the open position. As soon as opening movement ofswitch arm 46-is initiated, finger 72 of lever 66 pulls "cam member 76 arounditsfbearing 78 in a clockwise direction in Figure'l. Track 80 of cam member 76 is sodesigned that the clockwise rotation of cam member 76 will rapidly'move operatingrod 82 upwardly in Figure 1 and thus-cause almost immediate engagement of bridging heads 30 with by-pass contacts 26. The initial i asmeaa contact having b en api ade urt e c ockwi e ratation of cam member 76 will cause compression of springs 90 and 102 and thus cause secure seating of the bridging heads 36 between the contacts 26. When finger 72 of lever 66 reaches the outer end of track 74, operating rod 82 has reached the left end in Figure 1 of track of cam member 76 and snaps into the recess 84 under the action of spring 90, thus locking the bridging member in the closed position; The lever 66 being now free of cam 76, the main switch arms 44 and 46 can be pulled to the fully open position without further affecting the bridging member. Upon the reclosing of main switch arms 44 and 46, finger 72 of lever 66 will eventually engage face 104 of cam 76, enter track 74, and repeat the previously described operation in reverse. Due to the shape of track 86 of cam member 76, the actual withdrawal of bridging heads 36 from engagement with contacts 26 will take place very rapidly after the main switch arms have engaged the mainjcontacts 32 and 34. When the closing of the main switch arms is completed, lever 42 will abut against the top edge of contact 34 and cause hook 38 to engage flange 36, thus locking the main switch arms in closed position.

It will be seen from the above description that I have provided a novel construction of a high current by-pass switch which is simple to manufacture, positive in its action and has considerable structural strength. Although a particular embodiment of my invention has been described herein, many modifications thereof are obviously possible without departing from the spirit of my invention. I therefore do not desire to be limited by the embodiment herein described, but only by the, scope ofthe appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

l. A by-pass switch comprising at least one switch blade, 8. contact cooperating with one of said switch blades, a cam, an operating lever attached to at least one of said switch blades and engaging said cam, a movable support having a member engaging said cam for movement thereby, a plurality of contact heads individually mounted on said support and capable of omnidirectional planar movement, and a pair of fixed contacts, one of which is electrically connected to said contact cooperating with one of said switch blades, said cam being so arranged as to move said contact heads into engagement with said fixed contact when said switch blades are moved to the open position.

2. A by-pass switch comprising two pairs of terminals, a switch arm movable into and out of position to electrically connect a first pair of said terminals, and abridging member adapted to electrically connect one of said first pair of terminals to one of the second pair of terminals, said switch arm comprising a plurality of'switch blades resiliently mounted in spaced parallel relation and a reinforcing member rigidly connected to ahinge for rotary movement thereabout and having supporting arms for supporting switch blades for movement therewith, said reinforcing member having means thereon for plac ing said bridging member into connecting position when said switch arm is moved out of connecting position.

3. A by-pass switch comprising a switch member for controlling a first electrical circuit; a bridging. member for completing a second electrical circuit through a pair of stationary contacts, said bridging member comprising a plurality of independently movable juxtaposed contact heads, said contact heads having contact surfaces injthe shape of the translation of a line along a curved :path, whereby said contact heads are enabled to .seat them selves tightly between said stationary contacts regardless of the wear thereof; and means connecting said-switch member and said bridging member for placing said bridging member into closed-circuit position when said switch member is placed into open-circuit position.

4. In an electrical switch having a plurality of blades 5 q hingedly mounted for movement about an axis into and out of engagement with stationary contact surfaces, the improvement which comprises, a reinforcing member hingedly mounted for movement about said axis, said blades being resiliently mounted relative to said axis, and means connecting said blades with said reinforcing member, said means providing limited relative movement between said blades and said reinforcing member.

5. A contact structure for an electrical switch comprising a pair of stationary contacts, and a movable contact member for engaging said stationary contacts com- 6 prising an operating member, a support resiliently mounted on said operating member so as to be moved thereby, and a plurality of juxtaposed contact heads resiliently mounted on said support for limited movement with respect thereto.

References Cited in the file of this patent UNITED STATES PATENTS

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