US2314714A - Electric switch - Google Patents

Description

March 23, 1943. I KOUYOUMJIAN ELECTRIC SWITCH Filed Aug. 27, 1941 Marh23,1943. H KKQUYOUMJIAN 2,314,714

ELECTRIC SWITCH Filed Aug. 27, 1941 2 Sheets-Sheet 2 ,LJATToRNEY Patented Mar. 23 li@ UNIT STATES PATENT OFFICE ELECTRIC SWITCH Haroutium K. Kouyoumjian, Wakeeld, R. I. Application August 27, 1941, serial No. 408,413

(Cl. 20o-sn' 10 Claims.

The improved switches of this invention are applicable to various uses and for various purposes and are adapted to be modified readily for adaptation to particular requirements.

An important object of the invention is to produce an. electric switch oi comparatively small size having high current capacity and for use with moderately high voltages. Another object is to produce an improved form of structure in which the cost of material and the cost of manufacture will be comparatively inexpensive. Another object is' to produce a switch in which the contacts are of the butt type with comparatively large contact areas and thereby avoid the disadvantages of the blade type of Contact, particularly the deterioration of an effective contact engagement with continued use. Another object is to produce a quick make and quick break of the contacts in closing and in opening and to also provide a self-cleaning of the contacts in opening and in closing. A further object is to provide a switch with a multiplicity of contact making and current carrying parts in a compact form and to actuate the contacts in opening and closing by the use of a minimum number of springs; and also to secure by the spring action an equalization of pressure on all parts of the switch contacts with freedom of movement of each of the contacts for obtaining good contact engagement with all parts. Another object is to provide a number of breaks in series in opening the switch and to provide successive opening of contact elements so that one or more of the elements only is subjected to arcing while other of the contact elements are not subjected to arcing which insures the maintenance of good contact by the latter elements even if the former should develop an increase in` contact resistance. Another object is to provide a switch which will not be aflected by shocks or jars, that is, when the switch ls closed shocks will not tend to open it and when the switch is open shocks will not tend to close it.

Other objects and advantages will be understood from the following description and accompanying drawings which disclose certain embodiments of the invention.

Fig. 1 is a side view partly in section of a switch embodying eight contact engagements with four movable contact elements and showing the switch in the closed position; Fig. 2 is a section on the line 2-2 of Fig. 1; Fig. 3 is a similar view showing the parts in an intermediate position; Fig. 4 is a similar view showing the parts in the fully open position; Fig. 5 is an end View showing the switch adapted for operation by a push'and pull rod; Fig. 6 is a section on the line 6 6 of Fig. 7 showing the switch modied for controlling two different circuits; Fig. 7 is a section on the line l-l of Fig. 6; Fig. 8 is a section on the line 8 8 by a pair of bolts I3 and I3' passing through the plate I2 and through a. front metal cross piece Ill. Both ends of the bolts are threaded and the nuts I3a serve to clamp-the plate I2 and cross piece I4 together against the ends of the contact sleeves, the bolts and the sleeves being insulated from the cross piece I4 by insulating disks I6 and insulating sleeves I6a, as shown in section in the lower left-hand portion of Fig. 1. The bolts are also provided with nuts I3b for clamping the terminals of the outside circuit between them and the nuts I3a. Provision of this means for affording double connection to each of the contact sleeves is for convenience in wiring so that the leads may be connected to the front or rear terminals of the switch, such as may be desired.

A supporting shaft I1 for the movable parts of the switch is provided with a collar or disk Ila fixed to the shaft which engages the inner side of the plate I2, the shaft Il passing through the plate and secured in place by a clamping nut IIb on the rear threaded end of the shaft. On the front end of the'shaft is a sleeve I 8 which passes through the cross piece I4 and is provided with an enlarged portion at .its inner end forming a disk Illa positioned at the inner side of the cross piece. The operating handle I9 is of insulating material, or covered with insulating material and is fixed, as by a set screw I9a, to the sleeve Il.

The four conducting movable contact elements in the form of contact plates are divided into pairs, the elements of each pair being similar to thickness, as shown in Fig. 1, and the engage-` ment of the edges of the plates with the fixed fixed contact posts.

contacts gives a comparatively large contact engaging area, particularly because the curvature of the engaging edges of the plates conform with the curvature of the contact sleeves or post, as well shown in Fig. 2. Y The contact plates and 20a are freely rotatable upon the shaft Il; and the openings in these plates for the passage of the shaft are in the form of slots 20c for the purpose hereinafter explained. The inner pair of contact plates 2 l, 2|a vare likewise freely movable upon the shaft Il, the shaft passing through a slot 2|c in each plate of this pair. Each of the plates 2l and 2|a is similar in form to the other and of the form well shown in Fig. 2. The outer ends of each of these plates are in the form of extensions 2lb which respectively engage the fixed contact sleeves when the switch is in the closed position, as shown in Fig. 2. The edges of these extensions where they engage the contact sleeves are curved to correspond with the curvature of the contact sleeves so as to give a large contact engaging area not only by the thickness of the plates but by the engaging faces being of corresponding curvature.

The actuation of the four movable contact elements is secured by the provision of two springs which serve to quickly snap the contacts to closed position and during the opening movement vserve to snap the arcing contacts quickly to their open position after the movement of the other pair of contacts from the fixed contacts. Between each of the outer ends of the pair of contacts 20 and 20a extends a cross pin 20d which passes freely through the ends of the contact plates and is provided with an enlarged central portion 20e for spacing the plates from each other, as particularly shown in Fig. l. The inner pair of contact plates 2| and 2 la are spaced from the outer pair by washers 22. The opposite sides of the contact plates 2|Y and 2|a are provided at intermediate portions thereof with openings through which freely pass connecting pins 2id for operatively connecting the inner pair of contact plates. Each of these pins 2id is engaged at its central por' tion by an element 23 which serves to space the inner contact plates from each other and is provided with a head 23a having xed thereto a rod or pin 23h. The outer ends of these pins pass into and freely engage openings in the central portion of the enlarged parts 20e of the pins 20d. Between each of these enlarged portions 20e and the heads 23a. and encircling the pins 23d are springs 24 and 24a. The spring 24a is prefer:- ably made stronger than the pin 24 so as to exert a greater pressure upon the contact elements than the spring 24. It is apparent from the consideration of Fig. 2 that this assembly and relationship force of the springs is distributed individually upon each of the contact plates in a balanced relationship thereby insuring good contact pressure and engagement at each of the eight contacting areas; and this result is accomplished by the use of only two springs. In fact one of the springs could be omitted and the switch could still function properly, although not with the same degree of quick action or with the securing of the same degree of contact pressure.

The switch is actuated through the handle by the provision of a pair of pins 25 fixed to the front side of the contactplate 20a and positioned on opposite sides of the shaft i1, as shown in Fig. l. These pins project into openings in the disk Ia. vIt; follows that when the handle I9 is turned, it will rotate the contact plate 20a and thereby actuate the pins 20d and contact plate 20 and also swing the outer ends of the pins 23h. On the supporting plate I2 is fixed two posts 2G which project forwardly and serve as stops for the contact plates when the switch is thrown from the closed to the open position.

In operation, the opening of the switch will be considered rst and the movement of the parts from the closed position shown in Fig. 2 When the handle I9 is turned in a clockwise direction, the contact plate 20a will be similarly turned carrying with it the pins 20d and the plate 20. 'Ihis serves to separate the contact engaging parts of these plates from the contact posts without disturbing the contact plates 2l, 2Ia which remain in contact with the contact posts. The plates 20 and 20a are carried by the turning of the handle to the position shown in Fig. 3l when the two springs are then on a dead center line through the axis of the shaft Il. Further movement of the contact plates 20 and 20a and of the pins 20d carries the line of action of the springs on the other side of the dead center line which results in the springs then taking control of the opening action which quickly snap the of parts results in each of the contact elements y being firmly held against and in contact with the This is apparent because the spring 24 forces the pin 2 Id in such a direction as to hold the two contact plates 2| and 2 la firmly against the two contact posts While at the same time it exerts a force upon the pin 20d in a direction to hold the contact plates 20 and 20a against the contact posts on different portions thereof from that engaged by the contact plates 2| and 2 I a. Similarly the spring 24a cooperates with the spring 24 in forcing the respective con-v tact plates in firm engagement with the contact posts. Moreover, by reason of the comparatively free movement of the contact elements on the central shaft and on the pins 20d and 2|d, the

contact plates 2| and 2 la, from engagement with the contact posts and likewise react against the contact plates 20 and 20a and thereby throw all four contact plates against oppositesides of the stop posts 26. The parts then assume the condition shown in Fig. 4 and in this position the pressure of the contact plates are imposed on opposite sides of the posts 26 preventing undue strain thereon.

In this opening action it is apparent that by reason of the contact plates 20 and 20a first separating from the fixed contacts there is no appreciable arcing at their contact surfaces because all of the current is then caused to pass through the contact plates 2| and 2Ia. Thus the contact engaging areas of the contact plates 20 and 20a by not being subjected to any appreciable arcing serves to maintain these contacting areas in good condition and secure good conductivity of the switch even though the contact areas of the other pair of contact plates may have a somewhat increased contact resistance after long continued use; but when the contact plates 2| and 2Ia are separated from the fixed contacts, the action is controlled bythe springs which, as already explained, gives a quick opening action and thereby tends to minimize the arcing at the final opening of the switch. Also by reason of the fact that the switch is opened simultaneously at the two contact posts, there are two breaks in series with each other which further tends to reduce the arcing and in view of the two plates 2| and 2|a being in parallel this self-cleaning action is considerably increased. When the switch is in the open position. as shown in Fig. 4, the. diiierence in pressure of the springs causes the contact elements to be shifted to one end of Ythe slots 20c and 2Ic.

When the handle is moved to close the switch, this relative position of the shaft l1 in the ends of the slots is maintained until the faces of the movable contacts' engage the iixed contacts. But when this action occurs, then, by reason of the curvature of the contact surfaces of the movable contacts conforming in some degree to the curvature of the xed contacts, the pressure of the movable contacts by y,the two springs against the xed contacts causes the movable contacts to slide against the surface of the xed contacts so that the movable contacts will seat against the xed contacts ,with their contact areas conforming to' each other. 'Ihis latter sliding movement Athereby gives a self-cleaning action in arriving at the best position for securing maximum contact areas. In fact in this action there is more or less of an over-movement of the parts tending to increase the cleaning action in arriving at the final position of the parts. In securing this result, it is desirable that the difference 'in pressure exerted' by the two springs shall not be so great as to preventthis self-adjusting'and cleaning action. In opening the switch the reverse actionv occurs, thereby securing a self-cleaning sliding action in both the closing and opening movements.

Another advantage of the structure disclosed resides in the fact that if the surfaces of the contact sleeves should show any deterioration due to arcing, the bolts a may be loosened and rotated slightly so as to bring new contact areas opposite the contact areas of the contact plates. Also, if desired, the sleeves l5 and l5' may be loosely carried on the bolts so as to permit them tov turn on the bolts by the sliding action of the contacts in the opening and closing movements of the switch. In such a case it will, of course, be desirable to connect the sleeves by flexible leads to the bolts for securing good electrical connection therewith.

The arcing areas may be faced with materials of an arc suppressing character if desired and may be faced with silver or other material of high conductivity for improving the contact of the parts. Instead of making the contact encontacts is connected to the outside circuit by gaging areas of a curved form, they may be of other shapes for insuring proper centering of the contacts and may have -fiat engaging surfaces, although the curved vform is preferable in most uses. It is apparent that any number of these switches may be mounted upon a common shaft and arranged to operate in unison.

In Fig. 5 the handle I9 for operating the switch is replaced by an arm 21 attached to the sleeve i8 for the purpose of opening the switch by a push and pull actuator. Fig. 5 shows a rod 28 adapted to be manually operated in guides 28a.

The rod is provided with a pair of spaced projections 28h adapted to engage the outer end of the k:arm 21. It is apparent that when the rod 28 is pulled it will turn the arm 21 and open the switch in the manner already described with reference to Figs. l to 4. When the springs have been caused to assume a position just beyond the dead center position, the switch'will snap to the open position, the spacing ofthe projections 28h then allowing the arm 21 to move freely and quickly in the automatic opening of the switch, even if the operating rod 28 be manually held in a fixed position. In the closing of the switch the reverse action takes place, thereby securing a quick automatic opening and closing of the switch independently of 'the manually operated actuator. A

In Figs. 6, 7 and 8, the switch is shown as applicable to the control of two circuits instead of one as in the iigures previously described. In order to obtain the two circuit control, it is necessary tosub-divide the fixed contacts into two end portions insulated from each other and to sub-divide the four contact plates into two pairs of contacts, one of which comprises an outer and inner plate and the other of which comprises an inner and outer plate.

The parts of Figs. 6 to 8 'corresponding to those of Figs. l to 4 are similarly numbered, the main difference invr structure being the provision of insulation for certain parts. Thus the movable contact plates are shown insulated from each other by providing an insulating sleeve 29 around the supporting shaft i1; byvproviding an insulating washer. on the sleeve between the inner contact plates; and also insulating washers 30a between the inner and outer contact plates. They are vfurther insulated by insulating sleeves 3| on the pins 2id and by insulating washers 33 between the element 23 and the inner plates; also by insulating sleeves 33 on each end of the two pins 20d and by insulating washers 3c between' the parts 20e and the two outside con tact plates. Thel xed contacts, as shown in Fig.,8are each dividedinto two portions I5a and I5b insulated from each other by a central washer 3 5 and from the supporting bolts by an insulating sleeve 36. The 'front section l5b is also insulated from the cross piece i4 by an insulating washer 31. Each divided portion of the contact lugs 38 which are soldered to extensions 4from the fixed contact portions as indicated in f Fig. 8, although the outside circuit connections In utilizing the switch disclosed in Figs. 6 to 8.

as a two circuit switch, the lead of one circuit is connected to one of the xed contact portions I5a while the other lead will be connected 'to the other contact portion ISa on the opposite bolt; and one of the leads of the other circuit is connected to one of the contacts [5b. and the other lead to the contact Vlib on the other bolt. ,The operation of the diiierent parts of the switch is the same as described with reference to Figs. 1 to 4 as re-` gards the opening and closing of -each circuit. In the vclosed position the current in one circuit passes to one of the contacts i5a and then through the contact plates 20 and 2i in parallel to the opposite contact I5a and thence to the other terminal of the circuit. The current through the other circuit passes to one of the xed contacts |517 and then through the contact plates 20a. and 2Ia in parallel to the other fixed contact l5b and thence to the other terminal of this circuit. In opening the switch, the contact plates 2|) and 20a are first separated from their xed contacts, as indicated in Fig. '1 and then the final breaking of the current in the two circuits ocposition as already described. Also the sainev` sliding and self-cleaning action occurs in this structure.

In Figs. 9 and 10 the structure of the movable I portions of the switch is the same as that already described with reference to Figs. 6 to '1 except that the contact plates are adapted to engage fixed contacts on opposite end portions of each f the contact plates. As shown in Fig. 9, the supporting insulating plate I2a is provided with four fixed contact posts, two of these taking the place of thestop posts 26 of the former figures. Thus in Fig. 9 there are provided supporting bolts Ila for the fixed contacts. Each of these bolts is surrounded by an insulating sleeve 40 and at d1- ametrically opposite portions thereof are provided longitudinal extensions 40a. Each of the iixed contacts 4I is in the form of approximately half a cylinder and engages the sleeve and extends from one of the extensions 40a to the opposite extension 49a. Thus there are formed eight separately insulated fixed contacts, each of which is provided with an extension to which is secured a lead 42 for connection to the outside circuit. The fixed contacts are held in place on' the sleeves 49 by metal bands 43 which encircle the contacts of each post at opposite ends thereof and provided with an intervening band 44 of insulation, such as mica. The movable contact plates are similar to those already described except an additional contact surface 45 is provided neai' the end of each of the contact plates 2| and 2|a so as to form contact engaging surfaces with the added xed contacts. Likewise the Contact plates 20 and 20a are provided with contact surfaces 46 on their back portions near the ends so as to engage the xed contacts of the additional contact posts.

Fig; l1 shows the connections of a circuit to the fixed contacts for the purpose of using the switch as a reversing switch. The source is indicated by the incoming lines 41, 41 and avtranslating device is indicated at 48 in which the current is to be reversed. The line 41 is connected to a pair of fixed contacts 4l on the adjoining side of two posts. The line 41' is similarly connected to two contacts 4l, one of which is the contact of another post and the other of which is the contact mounted on a post which carries a contact connected to the line 41. One terminal of the translating device 48 is connected to one contact of the post which has its other contact connected to' The other terminal of the transtion in parallel between a. contact 4| o! the upper post and a contact 4l of the lower post. At the same time, the outer contact plates make a connection in parallel from the other contact 4| of the upper post to the other contact 4| of the lower post. This connection corresponds to the condition represented by the dotted line connections in Fig. 11 wherein the dotted line 48 corresponds to the connection made by the outer contact plates and the dotted line 50 corresponds to the connection made by the inner contact plates. This gives a circuit from the' positive line 41 to a contact 4I, the connection 49 to another contact 4l and then through the translating device in the ldirection 'indicated' by the dotted arrow to another contact 4| and .through the connection. to another contact 4l and then to the negative line 41'. When the switch is thrown from the position shown in Fig. 9 to a position such that the contact plates engage the contacts 4I of the left and right-hand posts, the condition corre-4 sponds to that shown in Fig. 11 by the full lines.

The circuit through the translating device is then from the positive line 41 to a contact 4l and then through the full line connection 5|, obtained by the outer contact plates, to a contact of the righthand post and then through the translating device in the direction indicated by the full line arrow to a contact 4I of the left-hand post and then through the connection 52, obtained by the inner contact plates, to a contact 4I of the right-hand post and' then to the negative line 41'. It is therefore apparent thatv when the switch is thrown from one extreme position to the other, it

serves as a reversing switch.

Although certain'embodiments of this invention have been shown and described, it will be understood that various modifications may be made therein and likewise the connections may be changed for adaptation to particular uses according to particular requirements.

I claim= 1. An electric switch comprising a pair of fixed contacts of cylindrical form, a pair of pivoted rotatable contact plates each simultaneously engaging the fixed pair of contacts by portions of each plate at opposite sides of the pivot by the edges of each plate by a butt contact, a pair of springs connected respectively between portions of said plates and opposite each other with refcrc-nce to the axis of the plates for exerting pressure on both of the plates in the-closed position in a directionto hold them in closed position, and means for rst moving one of the plates from the contacts and for moving the springs over their dead center positions for thereby causing the other plate to be snapped from its closed position to its open position and for moving the springs over their dead center positions :'n the opposite direction for thereby causing both of said plates to be snapped from their open position to their closed position, said plates being rotated in opposite directions with reference to each other in the opening and in the closing movements.

2. A two circuit switch' comprising two supporting posts, a pair of fixed contacts on each of said posts,.the contacts on each post being insulated from each other, four rotatable contact plates divided into an inner pair and an outer-pair, said contact plates engaging the fixed contacts on opposite portions of each plate in the closed position 'of the switch, the outer plate of one pair and the adjoining inner plate of the other pair being insulated from the other two adjoining inner plate of the other pair making engagement respectively with one of the fixed contacts on one of the posts and one of the fixed contacts on the other of the posts and the other outer plate and inner plate making contact engagement respectively with the other two contacts on the two posts, a spring connected between the plates of the outer pair and the plates of the inner pair for exerting pressure on the two pairs in opposite directions for holding the vfour plates in engagement with' their respective fixed contacts, and means for iirst moving the outer pair of contact plates from engagement with their fixed contacts, and moving said spring over its dead center position for snapping the inner pair of plates from their closed position to their open position and for exerting pressure for holding both pairs of contact plates in their open position.

3. A reversing switch comprising four iixed posts, a pair of fixed contacts on opposite sides of each of said posts and insulated from each other, a pair of rotatable outer contact plates for making engagement respectively between contacts on two opposite posts inv one position and between contacts on the other two of said posts in another position, a pair of inner contact plates for making connection between the other contacts of said first named two posts in one position. and between contacts of the other two posts in another position, the inner pair of contact plates being insulated from the outer pair of contact plates, a spring exerting pressure between the pairs of contact plates in opposite directions for holding said plates in engagement with their respective contacts in each of the two positions of said plates, and means for first moving one of said'pairs of contact plates out of engagement from its contacts in one position and for moving said spring over the dead center position for snapping the other pair of contact plates from engagement with its respective contacts and for actuating both of said pairs of contact plates into engagement with the other of said fixed contacts.

snapped by the spring to its open and closed positions respectively and to shift said plate in a direction at right-angles to its pivot inthe opening movement for securinga wiping action of the contacts.

6. An electric switch comprising a pair of fixed contacts, a pair of pivoted rotatable contact elements each simultaneously engaging the pair of fixed contacts in the closed position by portions of each elementv at opposite sides of the pivot, a spring exerting pressure on bothof the elements in the closed position in a. direction to holdthem in closed position, and means for first moving one of the elements from the pair of fixed contacts in one direction and for moving the spring over its dead center for thereby causing the other movable element to be snapped in the opposite direction from its engagement with the pair of fixed contacts to its open position.

'7. An electric switch comprising a pair of iixed contacts, a pair of pivoted rotatable contact plates each simultaneously engaging the pair of fixed contacts in the closed position by portions of each plate at the opposite sides of the pivot by the edges of each plate by a. butt contact, the spring exerting pressure on both of the plates in the closed position in .a direction to hold them closed-and in the open position in a direction to hold them open,andvmeans for first moving one of the plates from the pair of fixed vcontacts in one direction and for moving theV spring over its dead center position for thereby causing the other plate to be snapped in the opposite direction from its engagement with the pair of xed contacts to its open position.

8. An electric switch comprising a. pair of xed contacts, a pair of pivoted rotatable contact plates each simultaneously engaging the pair of fixed contacts in theclosed position by portions spring exerting pressure onboth of the plates 4. An electric switch comprising a xed contact having a curved contact surface, a pivoted movable contact in the form of a plate having a curved contact edge surface corresponding to.

the curvature of the contact surface of the fixed contact and engaging the fixed contact by the edge of the plate by a butt contact between said surfaces, said plate having an enlarged openingat its pivot for permitting movement of the plate. in a direction at right-angles to its pivot, a spring for actuating the movable contact, and' means for moving the spring over its dead center A position for thereby causing the movable contact to be snapped by the spring from its closed position to its open-position and to shift said plate in a direction at right-angles to its pivot inits opening movement for causing a wiping action of the contacts.

5; An electric switch comprising. af flxedcon-- tact having a curved contact surface. a pivoted movable contact in the form of a plate having a curved contact edge surface corresponding to the curvature of the contact surface of the fixed contact and engaging the fixed contact bythe edge of the'plate by a butt contact between said surfaces, a spring for actuating the movable contact, and means for moving the spring over its dead center position in opposite directions for thereby causing the movablecontact to be in the closed positionin a direction to hold them closed and in the open position in a direction to hold them open, and means for'rst moving one of the plates from the pair of fixed contacts in one direction and for moving the spring over its dead center position for thereby causing the other plate to be snapped in the opposite direction from its engagement with the pair of xed contacts to its open position and for moving `the springA over its dead center position for thereby causing both of said plates to be snapped `from open position to closed position.

9. An electric switch comprising a pair of xed contacts having curved contact surfaces, a pair of rotatable contact elements each having 0D- -positely Positioned curved contact surfaces corresponding to the curvature ofthe contact surfaces of the iixed contacts and engaging the fixed contacts by said opposite portionsvof each element by butt contacts between said surfaces. a supporting shaft for said elements, said elementsbeing shiftable on said shaft in a direction at right-angles to the axis of the shaft, a pair of springs connected respectively between said elements and opposite to each other with respect to said shaft for exerting pressure on each of said elements for holding each of them in engagement with the'fixed contacts, one of said springs exerting greater pressure than the other of said springs for shifting said elements in a ydirection at right-angles to said shaft for obtaining a wiping action of the contact engaging surfaces, and means for moving said springs over their dead center positions for moving said elements from the closed position to the open position.

10. An electric switch comprising a pair of xed contacts, two pairs of pivoted rotatable contact elements, each element simultaneosiy engaging the pair of fixed contacts in the closed position by portions of each element at the opposite sides of the pivot, one pair of .said elements being between the elements of the other pair, a, cross piece connecting the outer pair of elements, a cross piece connecting the inner pair of elements, a spring positioned between said two cross pieces for exerting pressure in opposite directions on said pairs of elements respectively for holding the contact elements in engagement with the xed contacts. and means for moving one ofsaid pairs of elements in one direction from engagement ywith the xed contacts for moving said spring over its dead center position for thereby causing the other pair of contact elements to be snapped in the opposite direction from its closed position to its open position and for moving said spring in the reverse direction over its dead center position to snap both pairs of contact elements in opposite directions to their closed position.`

HAROUTIUM K. KOUYOUMJIAN.

Images