US2743338A - Low voltage, high current switch - Google Patents

Description

April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT SWITCH 6 Sheets-Sheet 1 Filed Oct. 27, 1952 all April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT swI'rcH e Sheets-Sheet 2 Filed Oct. 27. 1952 so ll IN VENjOR. flaw/20 66992941 o fmhdfi Q 3% April 24, 1956 H. w. GRAYBILL 2,743,338

LOW VOLTAGE, HIGH CURRENT SWITCH Filed Oct. 27, 1952 e Sheets-Sheet 5 IN VEN TOR. o 8 flaw/yep 1/- wya/u.

April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT SWITCH 6 Sheets-Sheet 4 Filed Oct. 27. 1952 April 24, 1956 H. w. GRAYBILL 2,743,338

LOW VOLTAGE, HIGH CURRENT SWITCH Filed Oct. 27. 1952 s Sheets-Sheet 5 SOURCE LOAD oamkmR r 5M J 5 wry/616575 April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT SWITCH 6 Sheets-Sheet 6 Filed Oct. 2'7, 1952 United States Patent 0 LOW VOLTAGE, HIGH CURRENT SWITCH Howard W. Graybill, Greensburg, Pa., assignor, by mesne assignments, to I-T-E Circuit Breaker Company, Philadelphia, Pin, a corporation of Pennsylvania Application October 27, 1952, Serial No. 317,101 14 Claims. (Cl. 200-164) My invention relates to a novel short circuit switch and more particularly to a short circuit switch which lends itself to a flexible assembly into any desired combination such as for a single or multipole operation or operation in large units through a common operating handle.

In electrolytic process operations, the voltage across a cell is comparatively low, generally on the order of three to six volts. Since the output of the cell is directly proportional to the operating current, cells are usually designed for operation at high currents, usually in the range of 10,000 to 60,000 amperes. Hence, economic considerations dictate that individual cells be connected in series rather than in parallel.

With this type of electrolytic system, when one of the cells becomes defective for any reason and must be removed for inspection and repair, it is, of course, undesirable to shut down the entire line. It would be preferable to be able to remove the defective cell for inspection while the line is left otherwise intact for continuous operation.

The removal of such a unit may be achieved, as is well known in the art, by a switch inserted across the terminals of the defective pot cell to be removed. Thus, providing the shunt circuit in the series system with the switch that is connected across the cell, the latter can now be withdrawn from the system.

Inasmuch, however, as the system carries large currents, the switching device connected across the line must be able to carry these large current values across the contacts without any excessive RI drop which would generate heat at the contacts of the switch.

The large current which must pass through the con tacts often makes it desirable that a multiplicity of contacts be connected in parallel. For effective operation of a plurality of such contacts, provision must be made for self-alignment to insure simultaneous engagement and disengagement of the contacts.

Heretofore, short circuiting switches for pot line use were made with the conducting members thereof resilient so as to achieve high contact pressure. That is, the conducting members, which are to carry current loads as high as 60,000 amperes were constructed of or with resilient components, in order to insure good contact engagement. However, due to the fact that the conducting members were not rigid components, misalignment frequently occurred after prolonged use of the switches and due to the fact that these units were designed to carry relatively high magnitudes of current, the conducting surfaces were frequently burned and corroded after prolonged usage.

With my novel invention, I propose to overcome all of the disadvantages of the short circuiting switches of the prior art by:

1. Providing a structural arrangement in which all of the conducting members are rigid units and wherein (a) high contact pressure is obtained by biasing means independent of the conducting units and (b) structural con- 7 2,743,338 Patented Apr. 24, 1956 figuration permits the relatively small force of the biasing means to be resolved into relatively high forces which are normal to stationary conducting surfaces.

2. Providing a novel short circuiting switch wherein a plurality of bridging movable contacts are of identical structure and providing a unique construction whereby one of the plurality of movable contacts acts as an arc ing contact member.

Moreover, since such a switch will only rarely be used, there may be a tendency for corrosion at the contacts.

Accordingly, my invention contemplates a novel disconnect switch having silver to silver high pressure contacts, silver plated high conductivity hard copper, self aligning contacts and suitable terminal insulation.

Accordingly, an object of my invention is to provide a novel disconnect which is sufficiently flexible to permit its operation as a single or double-throw switch.

A further object of my invention is to provide a novel short circuiting switch in which each opening and closing operation is achieved with a wiping action.

A further object of my invention is to provide a novel disconnect in which high pressure contact engagement is secured over multipole contacts in parallel.

Another object of my invention is to provide a multipole high pressure switch in which self-alignment provides simultaneous contact engagement.

Another object of my invention is to provide a cell cutout disconnect switch having a plurality of cooperating contacts which are controlled from a single control shaft to insure simultaneous operation.

A further object of my invention is a novel disconnect switch constructed in a manner to increase the contact pressure just prior to full contact engagement and disengagement to insure wiping action under high pressure.

Another object of my invention is to provide a multipole short circuiting switch in which all of the movable contacts engage and seat with the stationary contacts individually and independently.

Another object of my invention is to provide a novel wedge shaped engagement between the conducting mem bers to thereby achieve line contact engagement.

A still further object of my invention is to provide a novel contact engagement means whereby the biasing vertical force can be resolved into two normal components to achieve a relatively high contact pressure.

A still further object of my invention is to provide a novel disconnect switch wherein all the conducting members thereof are rigid integral units.

A still further object of my invention is to provide a high current low voltage switch in which the resilient means to provide high contact pressure engagement is independent of the conducting materials thereof.

A still further object of my invention is to provide a short circuiting switch in which the mean length of the conducting path is relatively small to thereby reduce the millivolt or IR drop loss therein.

Still another object of my invention is to provide a novel switch in which the losses to the millivolt or IR drop are small.

Another object of my invention is to provide a novel circuit interrupting means in which the plurality of bridging contact members are uniform in construction and provide arcing and main contacts for the switch.

Still another object of my invention is to provide a short circuiting switch with a plurality of parallel bridging contact members wherein one contact member is connected to efiect contact engagement and disengagement before and after, respectively, and the engagement and disengagement of its associated bridging contact members.

Another object of my invention is to provide a dis connecting means with arcing and stationary contacts without the necessity of special construction for the contacts and wherein arcing and main contacts have identical construction.

V The structure and operation of the novel disconnect switch of my invention will best be understood from the following description taken in connection with the drawings, in which:

Figure l is a perspective view of one embodiment of my novel disconnect switch.

Figure 2 is a side view of the switch of Figure 1 showing the position of the member just prior to final contact disengagement when the operating shaft is rotated counterclockwise.

Figure 3 is a view of the switch of Figure 1 showing the position of the member when the contacts are in full disengaged position.

Figure 4 is a side view .of the disconnect switch of Figure 1 showing the position of the members when the contacts are in full disengaged position following clockwise rotation of the operating shaft.

Figure 5 is a perspective view of the bottom of the novel disconnect switch of Figure 1.

Figure 6 is a perspective view of another embodiment of a novel disconnect switch of my invention.

Figure 7 is an end view of the disconnect switch of Figure 6.

Figure 8 is a side view of the disconnect switch of Figure 6.

Figure 9 is a cross-section view of the switch unit of Figure .6 taken along the line AA of Figure 8.

Figure 10 is a top view of the disconnect switch of Figure 6.

Figure ll is a schematic diagram illustrating the cir- Quit and manner in which my novel switches can be connected in parallel for pot line or cell cutout application.

Figure 12 is a schematic wiring diagram illustrating how the novel switches of my invention can be used as a single pole, double throw switch. 7

Figure 13 is a schematic wiring diagram illustrating how the novel switches of my invention can be used as a double pole, single throw switch.

Figure 14 is a schematic wiring diagram illustrating how the novel switches of my invention can be used as a double pole, double throw switch.

Figure 15 is a perspective schematic view illustrating the manner in which the illustrated switches of Figures l1, l2, l3 and 14 can be interconnected to function simultaneously.

Figure 16 is a side view of a modified switch of my invention showing the bridging contact member in engagement with the stationary contacts and vectorially illustrates the increased contact pressure derived from the contact biasing spring.

Figure 17 is a perspective view of the modified switch of Figure 16 showing the conducting units in disengaged position and illustrates the position of the arcing contact with respect to the remaining bridging contacts.

Referring now to Figures 1, 2, 3, 4 and 5, the steel operating shaft 10 is the main control of the semi-cylindrical bridging contacts 11. The operating shaft 10 is journaled in the bushings which arepressed directly into the side plates 14 and 1S. Collars 12 and 13, concentric with the control shaft 10, are keyed thereto to prevent endwise motion of the shaft. The operating shaft 10 is provided with radial holes 21 to receive the shaft 22 of operating handle 23. Hence, the operating shaft 10 can be rotated clockwise and counterclockwise within the bearlugs ,12 and 13 by either upward or downward movement of the operating handle 23. The outer circumference of the operating shaft 10 has a plurality of U shaped stamped extension arms 16 rigidly secured to the operating shaft 10 and the legs 18 and 19 protrude radially therefrom. Each of the plurality of legs 18 and 19 is provided with an elongated slot 20 which extends radially from the operating shaft 10 and act as a support and guide for the pin 25. A pin '25 is transverse and integrally connected to one end of each of the contact arms 26. The other end of the contact rod 26 has the semicylindrical bridging contact 11 secured thereto which is preferably a silver surfaced copper block. Each contact rod 26 has a concentric spiral compression spring 26 preferably made of stainless steel, which rests at each end against the washers 28 and 29. Thus, when the control shaft 10 is in the closed position .of Figure l, the compression spring '27 will urge the bridging contact 11 downward into tight positive engagement.

The L shaped terminal connectors 30 and 31 are supported between insulator blocks 32, 33, 34 and 35. The terminal connectors 30 and 31 are rigidly secured to the channel or U shaped base plate by means of a plurality of bolts and nuts 41 and 42. The bolts 41 extend through the aligning insulators 33, 34 and 35, terminal members 30 and 31, insulator blocks 32, 33 and 34, U shaped base plate 40 and are secured in place by nut 42 as seen in Figure 5. Insulating tubes are placed around the bolts 41 to insulate. these members from terminal members 30 and 31 to insure that no potential exists between adjaccnt bolts 41. One end of the terminal connectors 30 and 31 is provided with appropriate means 38 for electrical connection to the circuit. The other end of the L shaped terminals 30 and 31 are milled at an angle of about 20 degrees from the perpendicular. These inclined surfaces of the copper terminals 30 and 31 are silver surfaced and form the stationary contacts which are bridged by the movable contacts 11.

The operation of the switch is as follows: when the movable bridging contact member 11, is in engagement with the stationary contacts and 51, the operating handle 23 is in the neutral or horizontal position, as seen in Figure 1. As manual upward pull on the operating handle 2.3 will rotate the operating shaft 10 in a counterclockwise direction. During the first 25 degrees of rotation of the operating shaft 10, the movable bridging contact 11 will be rotated with respect to the stationary contacts 50 and 51 thereby creating a wiping action between the contacts. The rotational movement of the movable contact 11 is caused by the relative movement between the pin 25 and the slot 20 of the leg 18. Hence, immediately prior to contact disengagement during opening operation, and as will hereinafter be apparent, immediately prior to contact engagement during the closing operation, there is a high pressure wiping action to remove any dirt or corrosion, from the stationary contact surfaces. That is, the contact compression spring 27 is compressed during the rotational movement between Figures 1 and 2 to insure high pressure wiping action.

After approximately 25 degree rotation of the operating shaft 10, the contacts will be in the position of Figure 2. As noted, the pin 25 of the contact rod 26 wit? now be at the lower end of the elongated slot 20 and the movable contact 11 will still be in engagement with at least a portion of the stationary contacts 50 and 51. However, with further rotation of the operaitng shaft 1t), relative movement between the pin 25 and the slot 20 is no longer possible since the pin 25 is now resting against the bottom of the slot 20. Hence, further rotation of the operating shaft 10 from the position of Figure 2 to the position of Figure 3 will withdraw the movable bridging contact 11 along a straight line to the position of Fig-- ure 3. That is, continued rotation of the operating shaft will lift contact member 11 up and out of engagement with the stationary contacts 50 and 51 of terminal members 3i] and 31. In this position, the contacts 11, 50 and 51 will be disengaged and the circuit will be interrupted. Although the contact 11 is disengaged from both the stationary contacts 50 and 51, a larger air gap will occur between contacts 11 and 50 than between 11 and 51, as best seen in Figure 3. It will be noted that this type of switch is used for high current low voltage application and hence, since very little voltage will occur between the contacts, the separation distance need not be very large.

It will be further noted that the switch can be opened by either clockwise or counter-clockwise rotation of the operating shaft 10. Figures 2 and 3 show the relative position and operation of the disconnect switch when the handle 23 rotates the operating shaft 10 in the counterclockwise position for opening. Figure 4 illustrates the relative position of the parts when the operating shaft is moved from the position of Figure 1 in a clockwise direction by means of operating handle 23. The manner and function of this operation is the same as that noted for counterclockwise rotation and differs only by having the larger air gap appear between contact 14 and stationary contact 51 rather than stationary contact 50.

It will be noted that the plurality of contact structures a, b, c and d are identical in construction and hence, the single rotation of operating shaft 10 will have the same efiect 011 all the bridging members 11. By this manner, simultaneous operation of the members is possible to insure that each parallel path is simultaneously broken.

The action of the switch for closing operation is the reverse of that described for the opening operation. That is, the handle 23 is moved clockwise from the position of Figure 3 and the movable member is moved through the position of Figure 2 to the position of Figure 1. Thus, the operating handle 23 will again be in its neutral or horizontal position.

As the movable contact 11 is moved from the position of Figure 3 to the position of Figure 2, it will move downward in a straight line to the left. Hence, if prior to its rotational movement from that of Figure 2 to Figure l, the movable contact 11 will engage the insulating block 33, the member 33 will there act as a guide or aligning unit to insure that the semi-cylindrical bridging member 11 will rotate into proper engagement with stationary contacts 50 and 51. Hence, rotation of the operating shaft 10 closes the switch unit by engaging the four self-aligning bridging contacts 11 directly between the stationary contacts 50 and 51 of terminal members 30 and 31.

When the switch unit is in the engaged or closed position, the current flow will be through terminal connector 31 (from the electrical connection at 38 which is not shown), through stationary contact t divided into four equal parallel paths through bridging contact 11, through stationary contact 50, terminal connector 30 and to the line (not shown) connected at 38.

Thus, in summary, I have provided a novel short circuiting switch wherein the main current conducting members 30-50, 11 and 31-51 are all rigid integral units with high contact pressure being supplied from biasing means 27 which is independent of the current conducting members. Hence, due to the fact that all of the conducting units are rigid members, the high current low voltage switch is a rugged device which will not misalign after repeated usage.

As heretofore mentioned, the prior art short circuiting switches required that that conducting members have re silient properties in order to achieve high contact pressure and thus, frequently misaligned after extensive use.

By providing independent biasing means, such as compression spring 27, it is possible to have a short current path of heavy cross-section, since deflection of conducting members is not required.

Furthermore. by providing a unique arrangement in which the biasing means 27 is individual and independent to each of the bridging contacts 11, the plurality of movable contacts are able to seat themselves individually and independently during contact engagement. That is, the final seating of the movable contact 11 within the wedge shaped stationary contacts 50 and 51 permits the compression spring 27 to adjust and seat its associated movable 6 contact 11 therebetween irrespective of the position of the remaining movable contacts.

It is further noted that with my unique switch, contact engagement, as the switch moves from the position of Figure 3 through the position of Figure 2 to the position of Figure l, is achieved primarily by the action of the compression spring 27. That is, as the operating shaft 10 is rotated from the position of Figure 3 to the position of Figure 2, the contact bar 27 is moved downwardly and in the position of Figure 2 the cam 18 urges the washer 33 downwardly to compress the contact spring 27. Hence, the compressed spring 27 represents the link between the operating shaft 10 and the bridging contact 11 to urge the latter member from the position of Figure 2 to the position of Figure 1.

Since this latter motion is achieved while the contact spring 27 is under compression, the wiping action occurs under high pressure. In contra-distinction, the disengagement of the contacts from the position of Figure 1 through the position of Figure 2 to the position of Figure 3 is achieved through the linkage mechanism of the cam 18 and the contact rod 26.

That is, the contact disengagement is caused by the action of the cam 18 on the contact rod 26 and occurs without benefit of the energy of the biasing means 27. Hence, contact disengagement or the pulling away of the movable contact 11 from the stationary contacts 50-51 is achieved by the positive linkage of 11, 26, 25, 18, 10 independently of the spring 27 whereas contact engagement is made at the benefit of the force from biasing spring 27, as above noted.

A modification of the novel switch shown in Figures 1 through 6 is shown in Figures 16 and 17. The modified switch of Figures 16 and 17 differs in the following respects:

(1) A unique construction for the assembled movable contacts permits one of these contacts to engage and disengage the stationary contacts before and after, respectively, the other movable contacts engaging and disengaging the movable contacts. This construction enables one of the moving contacts to act as an arcing contact to thereby insure that no pitting or burning will occur at the other movable contacts.

(2) The moving contact lever is made with a hair pin construction to replace the contact rod 26. That is, in the embodiment of Figures 1 through 6, it was necessary to provide an elongated slot in the rod 26 in order to insure that each of the movable contacts seated individually and independently. However, with the unique hair pin construction of the moving contact lever, as shown in Figures 16 and 17, the necessity of providing an additional elongated slot, entailing increased manufacturing difficulties and expense, is eliminated.

(3) A blocking insulator 35, as seen in Figures 1 through 6, is replaced by a channel shaped conducting member which (a) due to its heat conducting properties, conducts excess heat away from the contact engaging surfaces, (b) permits freer circulation of air around the contact engaging surfaces. and (0) provides a plurality of radiating fins to dissipate the heat conducted therein into the air by means of radiation.

As best seen in Figures 16 and 17, operating shaft 10 is provided with a plurality of integrally attached U- shaped members 201. The movable contact member 110, identical in construction to the movable contact members 11, as seen in Figures 1 through 6, is provided with an U- shaped moving contact lever 202.

The hair pin 202 is permanently secured to the bridging contact member 11a by means of screws 203, 204 inserted through the feet 205-406 of the hair pin member 202.

The movable contact assembly, comprising a movable contact lla and a hair pin member 202, is rotatably mounted to the U-shaped cam 201 by means of the pin 208 which is positioned in the channel formed by the plurality of members 201-202.

The bus terminal connectors and 31 are identical in construction to the bus terminal members of the embodiment of Figures 1 through 6 and are provided with beveled edges -51 forming wedge shaped stationary contacts.

Channel members 210-211 are secured to the upper surface of the bus terminal members 30-31 by means of bolt and nut arrangements 212-213. The bolts 212- 213 are provided with insulating sleeves 215-216 and serve to connect the insulators 218-219-220-221 to the bottom surface of the bus terminals 30-31.

In the embodiment of Figures 1 through 6, the insulating members 33-35 are positioned on top of bus terminals 30-31 to serve as guides for the movable contact members 11. However, in the modified embodiment of Figures 16 and 17, these insulating members are replaced by the channel units 210-211. The flanges 225- 226 of these units serve as guides to insure proper seating of the movable contact member 11 into the wedge shaped stationary contacts 50-51.

The channel shaped members 210-211 are also provided with flanges 227 and 228, which, along with flanges 225 and 226, serve to radiate the excess heat which is conducted through the members 210 and 211 from the conducting area at 50-11a and 51-11a. It will be further noted that by providing channel shaped members 210 and 211, greater circulation of air is permitted around the conducting surfaces to thereby enable the heat to be more readily dissipated.

Asbest seen in Figure 14, a vectoral diagram is superimposed on the end view of the short circuiting switch. It will be noted that the distribution of forces, as herein more fully explained, applies to both the embodiment of Figures 1 through 6 and the modified embodiment of Figures 16 and 17. It will be further noted that the magni tude of the various vectoral components indicated is merely illustrative as to proportions of the forces and may be varied within wide limits for practical and com mercial applications.

As heretofore noted, the beveled edges 50-51 of the bus terminals 30-31, forming wedge shaped stationary contacts into which the semi-cylindrical movable contact 11a is seated when the contacts are in engaged position. Hence, a point or a line contact is made between conducting members 11 and 30-31 at the points 230-231 to thereby enable all of the available force to be concentrated in a relatively small area to thereby increase the contact pressure.

The seven pound downwardly extending vertical force is representative of the force exerted on the movable contact 11a from the contact compression spring 27.

As will hereinafter be apparent, with my novel wedge shaped engagement of the conducting surface, the downwardly extending vertical force from the spring 27 is resolved into components which act normal to the stationary contacts 50-51 and have a magnitude greatly in excess of the vertical force to thereby obtain high contact pressure.

The seven pound downwardly extending vertical force may be vectorally illustrated by the two 3.5 lb. downwardly extending vertical forces at points 230-231. This downwardly extending force of 3.5 lbs. when resolved into its components, results in a horizontal force of 9.6 lbs. and a normal force to the surfaces 50-51 of 10.2 lbs. as indicated.

Hence, contact pressure between the movable contact 11a and the stationary contacts at 50-51 will be of the magnitude of 10.2 lbs. at the line engagement 230-231. That is, with my novel arrangement, a relatively small downwardly extending vertical force of seven pounds from the compression spring 27 may be resolved into components which enable a 10.2 lb. force to be exerted at the point of contact engagement.

As'above noted, a modified embodiment of Figures I6 arid r7 prdvidesa hovelstructttral arrangement for short ircuiting switch wherein an the movable contacts are of identical construction and so arranged that one of the plurality of bridging members serves as an arcing contact to thei'cby'rclleve'tlieremaining conducting members from the burden of interrupting the circuit.

Referring now to Figures 16 and 17, the plurality of movable contacts 11a, 11b, 11d, 11e have the hair pin member 202 directly connected to the upper flat surface thereof. Hence, these four movable contact members, which are designed with sutficient cross-sectional area to carry the full load to be shorted or opened by the high current low voltage switch, are in substantially the same horizontal plane and will, therefore, engage and disengage the stationary contacts 50-51 at substantially the same time.

The center movable contact 110, as best seen in Figure 17, is provided with a washer 250 which is seated below the feet 205-206 of the hair pin 202 and the bridging contact 110.

it will be noted that with the exception of additional washer means 250, the entire movable contact assembly consisting of movable contact 11a, hair pin member 202 and compression spring 27 are identical in construction to the remaining movable contact structures 11a, 11b, 11d and 11a. However, the insertion of the additional washer means 250 permits the center movable contact structure 11( to be seated lower than the remaining four units.

Hence, when the operating shaft 10 is rotated to effect contact engagement, the movable contact 11c will engage the stationary contact before the remaining movable contacts 11a, 11b, 11d, 11e are brought into engagement.

It will be noted that after the contacts are in full engaged position, as seen in Figure l6, they are all seated on the same horizontal plane. That is, even though the center contact 11c is provided with additional washer means 250, stationary contacts 50-51 prevent it from moving further down than the remaining bridging contacts 11 a, b, d and e.

Thus, the contact spring 27 associated with the contact structure of 1.10 will be compressed to a greater extent than the remaining contact springs to enable its associated movable contact to seat itself within the wedge shaped stationary contacts in the same plane as the remaining movable contacts.

Thus, due to the fact that the compression spring 27 of the movable contact assembly 11c is compressed to a greater extent than the remaining compression contact springs, the wiping action of this arcing contact will occur under greater pressure than the remaining structures to thereby more readily remove the excess pitting which occurs on contact structure 110, as above noted.

In like manne, due to the fact that the washer means 250 permits the movable contact structure to be seated below the remaining contacts, contact structure 110 will be the last unit to disengage from the stationary contacts. That is, when the operating shaft 10 is rotated to effect contact disengagement, the plurality of movable contacts 11a. 11b, 11d and lie will disengage the stationary contacts before the center contact structure 110 disengages same. Hence, the entire burden of arcing and resulting pitting of contact surface will occur on the one movable contact structure, namely 110 so that it acts in substantially the same manner as an arcing contact, as is well known in the art.

By this novel arrangement, I am able to provide a short circuiting switch in which the plurality of movable contacts are designed to have sufiicient cross-sectional area to carry the full load requirements of the switch and in which the added identical contact structure is provided to carry the interrupting burden and the switch. Thus, by this arrangement, only contact 11c will become pitted or burned threw the interrupting dutiesthus preserving the conducting surfaces of the remaining bridging members 11a, 11b, 11d and He.

Another embodiment of my invention is illustrated in Figures 6, 7, 8, 9 and 10. In this embodiment, the position of the bridging movable contact is also controlled by the rotation of a control shaft. However, the bridging member is a flat conducting member rather than a semicylindrical unit and follows only vertical linear movement rather than rotational and linear movement.

The main operating shaft 60 is journalled in the bearing members 61 and 62 which are mounted on support members 63 and 64. The support members 63 and 64 are in turn rigidly secured to U shaped base plate 66, comprising legs 67 and 68 and base 69 by means of bolts 75. The base plate 66 is made of a suitable electrical insulating material, such as phenolic plastic. A pair of col lars 120 and 121 are secured to the operating shaft 60 adjacent to the bearings 61 and 62. By means of collars 120 and 121, longitudinal movement of the shaft 60 is restricted and its movement is thereby limited to rotation. The operating shaft 60 has a plurality of cam members 76 and 77 rigidly attached to its outer peripheral surface. The cam members 76 and 77 engage the longitudinal bar 78. The longitudinal bar 78 has protrusions 79 and 80 at each end located above the extensions 85 and 86 on legs 67 and 68 of base support 66.

Compression springs 90 and 91 are seated between protrusions 79 and 80 and extensions 85 and 86 to bias the longitudinal bar 78 upward. The longitudinal bar 78 is seated above the extension 85 and between the legs 67-67 and 68-68 of U-shaped base plate 66. Hence, the positioning of bar 78 in the cutout of legs 67 and 68 will insure that the bar 78 has no transverse movement and the end supports 63 will limit the longitudinal movement of this unit. Thus, the longitudinal bar 78 will be limited to vertical movement.

A plurality of H-shaped leaf springs 92 and 93 are secured to the longitudinal bar 78 by means of screws 95. Each leg of the H-shaped leaf springs 92 and 93 is attached to a copper bridging contact 98 by means of attaching screws 100 and 101. Silver contacts 102 and 103 are welded to each end of each of the plurality of bridging contacts 98. When the assembly comprising the longitudinal bar 78 and bridging contact 98 is moved downward by action of the operating shaft U shaped cam 76, the silver contacts 102 and 103 will engage the stationary contacts 105 and 106. The plurality of stationary contacts 105 and 106 are secured to L shaped terminal connectors 107 and 108. The L shaped terminal connectors 107 and 108 are secured to the bottom side 69 of the U shaped base plate 66 by means of bolts and nuts 110 and 111. The switch unit is connected in an electrical circuit by making appropriate connections at 112 and 113 on terminals 107 and 108, respectively. When the switch is in the engaged or operating position of Figure 6, the flow of current is from the line to the terminal connector 107 by means of connection at 112, through the plurality of stationary contacts 105 to the four parallel paths of movable contact 102, copper bridging member 98, movable contact 103, stationary contact 106, through terminal connector 108 and then to the electrical circuit connected thereto at 113.

The operation of the switch unit is as follows. When the switch is in the open position, as shown in Figures 7, 8, 9 and 10, the bridging member 98 and its associated movable contacts 102 and 103 are biased to the disengaged position by means of compression springs 90 and 91. In order to bring the contacts into engaged position, the operator rotates the operating shaft 60 in either a clockwise or counterclockwise position. Initial rotation of the operating shaft 60 will rotate the integrally attached cam member 76 into engagement with the longitudinal bar 78. Continued rotation of the operating shaft 60 will depress the longitudinal bar 76 against the bias of compression springs 90 and 91. When the movable contacts 102 and 103 engage stationary contacts .105 and 106, respectively, continued downward movement of thebar 78 by the cam 76 will cause the leaf springs to deflect. In the final engaged position, as seen in Figure 6, the bottom leg 76' is seated on top of the longitudinal bar 78 to prevent accidental opening due to shock or vibration. I n this position, contacts 102 and 105, 103 and 106 are in engagement and hold in tight contact due to the resilience of leaf springs 92 and 93.

Action of the switch for opening is the reverse of that described for closing. That is, the operating shaft 60 can be manually rotated in either a clockwise or counterclockwise direction to thereby remove the cam 76 from engagement with longitudinal bar 78. This action will permit the compression springs and 91 to move the bar 78 and associated bridging member 98 upward to thereby effect contact disengagement between 102 and 105, and 103 and 106.

The switch of my invention including the embodiment of Figure l and Figure 6 is primarily a low voltage high current device for potline or cell cutout application. For example, in cases where a plurality of cells a, b are connected in series across a source 111, it is undesirable to close down the entire network in the event that one cell becomes defective or needs replacing. Hence, for example if cell 10a should require replacing, a plurality of disconnect switches 112 would be connected in shunt with the defective cell. The plurality of switches 112 can be operated from a single operating shaft 60 to simultaneously close all the contacts 11, 50, 51 and thereby short out the cell 110a so that it may be repaired or replaced.

It will be further noted that the switches of my invention can be arranged so that a plurality of switches can be operated from a single shaft as seen in Figures 11 and 15. Furthermore, the switch of my invention can be used as either a single pole double throw, double pole single throw, or double pole double throw switch.

Figure 12 illustrates the arrangement and connection for the switches as a single pole double throw unit oper-- ated from a single control shaft 60. For this arrange ment, one switch unit (a) is in the closed position when the other switch unit is in the open position for a particular position of the operating shaft 60. For double polefsingle throw operation, as seen in Figure 13, both switch units a and b are simultaneously in open or closed position.

For double pole double throw application, as seen in Figure 14, four switch units a, b, c and d are required to be connected and arranged so that the pair of switch units a and b are open when the pair of switch units: 0 and d are closed. Hence, when the shaft 60 is rotated to close the switch units a and b, the left load will be connected to the source. When the operating shaft 60 is rotated to open units a and b and close switch units 0 and d, the right load will be connected to the source. For double pole applications, an insulating section is inserted in the connection between shafts of opposite polarity.

In the foregoing, I have described my invention only in connection with preferred specific embodiments and applications thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

1. In a disconnecting switch having a plurality of movable contacts and a pair of stationary contacts having a wedge shaped gap therebetween, means for simultaneously operating said plurality of movable contacts into said wedge shaped gap for engagement with said pair of stationary contacts; a guide member engaged by said plurality of movable contacts prior to their engagement with said pair of stationary contacts for automatically align- 11 ing said plurality of movable contacts prior to their engagement with said pair of stationary contacts to provide simultaneous contact engagement of said plurality of movable contacts with said pair of stationary contacts.

2. A circuit interrupter comprising relatively movable contacts, a pivoted toggle member to open and close said contacts, operating mechanism comprising a pivoted operator manually movable to effect opening and closing movement of said contacts, said toggle member being pivotally connected to said manual operator, one of said contacts connected to one link of said pivoted toggle, a compression spring located between said contact and the knee of said toggle to bias said contact into electrical engagement with a stationary contact.

3. In a circuit interrupter comprising a cooperating electrical contacts, having a movable contact to bridge two stationary contacts when in closed position, rotational means to manually position said movable contact with respect to said stationary contact, said rotational means imparting rotational and linear movement to said movable contact to insure wiping action and relative contact movement, said linear movement imparted to said movable contact by said rotational means being in a direction perpendicular to the plane of said stationary contacts.

4. In a disconnect switch comprising a plurality of cooperating contacts for completing and interrupting an electrical circuit between a pair of bus bar terminals, operating means rotatably supported on a switch support frame comprising a shaft with a plurality of integrally connected U shaped flanges protruding therefrom, each leg of said U shaped flanges having a receiving slot, a plurality of actuated arms each having a transverse pin integrally connected at one end thereof and a semi-cylindrical movable contact integrally connected at the other end thereof, said actuated rod slidably secured to said U shaped flanges by engagement of said pins with said re ceiving slots. a biasing compression spring concentric with each of said actuating arms seated at one end on a fiat surface of said semi-cylindrical movable contact and seated at the other end on the legs of said U shaped flanges. said U shaped flange and said actuating arm being in axial alignment with said movable contact is in engagement with the stationary contacts of said bus bar terminals, rotation of said operating means elfective to wipe said movable contact against said stationary contacts and to move said movable contact out of engagement with said stationary contact.

5. In a disconnect switch having stationary contacts engageable by movable contacts comprising a control shaft, biasing means and washers; said control shaft having a plurality of cams integrally attached thereto, said control shaft connected to said movable contacts by engagement of said cams with said washers to control the operation of said movable contacts through said biasing means.

6. In a disconnect switch having stationary contacts engageable by movable contacts comprising a control shaft, biasing means and washers; said control shaft having a plurality of cams integrally attached thereto, said control shaft connected to said movable contacts by ongagement of said cams with said washers to control the operation of said movable contacts through said biasing means, said biasing means operatively connected to insure contact pressure during contact engagement, said movable contact having a moving contact lever integrally attached thereto, said control shaft connected to effect contact disengagement through said cams and "said moving contact lever independent of said biasing means.

7. A short circuiting switch comprising ajpair of cooperating contacts for opening and closing an electrical circuit, said cooperating contacts comprising asemi-cylindrical movable contact and a pair of bus terminals having beveled edges forming stationary contacts, said beveled surfaces of said pair of bus terminals forming a wedge shape to receive said semi-cylindrical bridging contact, said bridging contact making tangential line contact with said beveled edges, said Wedge shape engagement of said movable contact with said stationary contacts permitting a relatively small vertical force to be resolved into two relatively high normal forces to said beveled surfaces to thereby achieve high contact pressure, said semi-cylindrical movable contact having rotational and linear movement with respect to said pair of bus terminals, said linear movement of said semi-cylindrical movable contacts being perpendicular to the plane of said bus terminals.

8. A short circuiting switch comprising a pair of cooperating contacts for opening and closing an electrical circuit, said cooperating contacts comprising a semi-cylindrical movable contact and a pair of bus terminals having beveled edges forming stationary contacts, said beveled surfaces of said pair of bus terminals forming a wedge shape to receive said semi-cylindrical bridging contact, said bridging contact making tangential line contact with said beveled edges, said semi-cylindrical movable contact engagement with said Wedge shaped stationary contacts effective to cause high contact pressure engagement therebetween. said semi-cylindrical movable contact having rotational and linear movement with respect to said pair of bus terminals, said linear movement of said semicylindrical movable contacts being perpendicular to the plane of said bus terminals.

9. A short circuiting switch comprising a pair of co operating contacts for opening and closing an electrical circuit, said cooperating contacts comprising a semi-cylindrical movable contactand a pair of bus terminals having beveled edges forming stationary contacts, said beveled surfaces of said pair of bus terminals forming a wedge shape to receive said semi-cylindrical bridging contact, said bridging contact making tangential line contact with said beveled edges, resilient means to bias said semicylindn'cal movable contact into engagement with said stationary contacts, said resilient means exerting a biasing force on said semi-cylindrical movable contact in a direction perpendicular to the plane of said pair of bus terminals, said wedge shaped engagement of said movable contact with said stationary contacts causing said biasing force of said resilient means on said movable contact to be resolved into two forces of greater magnitude to thereby achieve high contact pressure.

10. A short circuiting switch comprising a pair of cooperating contacts for opening and closing an electrical circuit, said cooperating contacts comprising a semicylindrical movable contact and a pair of bus terminals having beveled edges forming stationary contacts, said beveled surfaces of said pair of bus terminals forming a wedge shape to receive said semi-cylindrical bridging contact, said bridging contact making tangential line contact with said beveled edges, resilient means to bias said semi-cylindrical movable contact into engagement with said stationary contacts, said resilient means exerting a biasing force on said semi-cylindrical movable contact in a direction perpendicular to the plane of said pair of bus terminals, said wedge shaped engagement of said movable contact with said stationary contactscausing said biasing force of said resilient means on said movable contact to be resolved into forces perpendicular to said beveled edges, said last mentioned forces being of greater magnitude than said biasing force of said resilient means to thereby effect high contact pressure engagement with relatively small biasing force.

11. A disconnect switch comprising a plurality of operating contacts for completing and interrupting an electrical :circuit between apair of bus bar terminals, rotatable operating means comprising a shaft having a plurality of integrally connected cams, a-phirality of semi-cylindrical bridging contact members,.n'movingcontact lever secured to each of said semi-cylindrical bridging contacts, said moving contact levers rotatably attached to said plurality of cams, compression springs concentric with each of said moving contact levers and positioned between said semicylindrical bridging contacts and said cams, said operating means transmitting force to said semi-cylindrical movable contact through said compression spring.

12. A disconnect switch comprising a plurality of operating contacts for completing and interrupting an electrical circuit between a pair of bus bar terminals, rotat able operating means comprising a shaft having a plurality of integrally connected cams, a plurality of sernicylindrical bridging contact members, a moving contact lever secured to each of said semi-cylindrical bridging contacts, said moving contact levers rotatably attached to said plurality of cams, compression springs concen tric with each of said moving contact levers and positioned between said semi-cylindrical bridging contacts and said cams, said operating means transmitting force to said semi-cylindrical movable contact through said compression spring, said rotatable engagement between said movable contact levers and said plurality of cams permitting said semi-cylindrical movable contact to rotate into bridging position between said stationary contacts, said rotational engagement of said movable contact with said stationary contact causing a wiping action therebetween, said compression spring causing said wiping action to occur under pressure.

13. A disconnect switch comprising a plurality of operating contacts for completing and interrupting an electrical circuit between a pair of bus bar terminals, rotatable operating means comprising a shaft having a plurality of integrally connected cams, a plurality of semicylindrical bridging contact members, a moving contact lever secured to each of said semi-cylindrical bridging contacts, said moving contact levers rotatably attached to said plurality of cams, compression springs concentric with each of said moving contact levers and positioned between said semi-cylindrical bridging contacts and said cams, said operating means transmitting force to said semicylindrical movable contact through said compression spring, said compression springs individual to each of said semi-cylindrical movable contacts permitting same to engage and seat with said stationary contacts independently and individually of each other.

14. A disconnect switch comprising a plurality of operating contacts for completing and interrupting an electrical circuit between a pair of bus bar terminals, rotatable operating means comprising a shaft having a plurality of integrally connected earns, a plurality of semicylindrical bridging contact members, a moving contact lever secured to each of said semi-cylindrical bridging contacts, said moving contact levers rotatably attached to said plurality of cams, compression springs concentric with each of said moving contact levers and positioned between said semi-cylindrical bridging contacts and said cams, said operating means transmitting force to said semi-cylindrical movable contact through said compression spring, one of said movable contacts positioned below said other movable contacts when said disconnect switch is in circuit interrupting position, said one movable contact engaging said stationary contacts before said other movable contacts, said one contact disengaging said stationary contacts after disengagement of said other movable contacts with said stationary contacts to thereby act as an arcing contact.

References Cited in the file of this patent UNITED STATES PATENTS 1,531,917 French Mar. 31, 1925 2,529,662 Pipponzi Nov. 14, 1950 2,555,025 Cheek May 29, 1951 2,557,493 Andis June 19, 1951

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