US2205497A - Disconnecting switch - Google Patents

Description

June 25, 1940.

A. C. SCHWAGER ET AL DISCONNECTING SWITCH 4 Sheets-Sheet 1 Filed April 11, 1938 INVENTORS SCH WA 652' BEOCK A. E. BY 2. 5. 052 420 June 1 AC. SCHWAGER ET AL 2,205,497

DISCONNEGTING SWITCH 4 Sheets-Sheet 2 Filed April 11, 1938 INVENTORS H WA GE June 25, A. c; SCHWAGER ET AL 7 DISCONNECTING SWITCH Filed April 11, 1938 4 Sheets-Sheet s INVENTORS A. C. SCHWA GEE 4w WMERNEY J 1940- A. c. SCHWAGER ET AL DISCQNNECTING SWITCH Filed April 11, 1938 4 Sheets-Sheet 4 INVENTORS A. C. S'C'H WAGEE A. E. BROOK BY 2.!1'. GE EAED m I TTORNEY Patented June 25, 1940 UNITED STATES PATENT OFFICE DISCONNECTING SWITCH Application April 11,1938, Serial No. 201,344

4 Claims. (Cl. 200-'-48) The present invention relates to a high voltage electrical switching apparatus, and more particularly to a disconnecting switch wh"h is adapted for use in outdoor sub-stations for sec- :ionalizing high tension electrical transmission mes.

; An object of the invention is to provide an improved high tension air break switch and operating means therefor, which is adapted for use on either a single or multiphase electric power transmission circuit, where it is desiredto sec- .tionalize the transmission line or to connect and disconnect a branch circuit at its point to intersection with the main power line, as at a substation.

, Another object of the invention is to provide an improved operating means for a disconnecting switch of the above character, in which the switch blade is easily and positively controlled at all times by the operating mechanism.

Another object of the invention is to provide a new and improved form of spring type counterbalancing means for a vertically movable switch blade that will substantially counterbalance the moving switch blade in all of its positions without imparting any actuating force. thereto.

Another object of the invention is'to provide a high contact pressure producing mechanism which is adapted to be operated by the switch blade operating mechanism when the switch blade has been moved into cooperating relation with a stationary contact, and in which the switch blade will be under positive control of its operating mechanism.

Another object of the invention is to provide a new and novel form of switch blade controlling and contact pressure producing mecha nism, in which the switch blade operating mechanism will be rendered operative to actuate the contact pressure producing means 'when theswitch blade has been moved into its circuit closed position without imparting a further closing movement to the switch blade.

Switches of the character contemplated by this invention are generally mounted in the open,-

where they are subjected to extreme weather conditions, and as a result it is desirable that the cooperating contacts of the switch be made so that they can be easily moved into and out of engagement with each other, and at the same time provide a high contact pressure between the cooperating contacts. Therefore it is another object of the present invention ,to provide an improved contact pressure producing mechanism which can be operated by a blade operating mechanism after the switch blade has been moved into cooperating relation with its stationary contact.

A further object of the invention is to provide a new and novel design for a high tension disfaces are rounded to remove sharp corners and thus avoid corona-discharge therefrom.

With the above and other objects in view, the present invention contemplates a special form of switch blade and cooperating contact and an .improvedsactuating mechanism therefor, which connecting switch, in which all exterior surcontact before it becomes operative to move the switch blade into its open circuit position.

For a better understanding of the invention, reference should be had to the accompanyingdrawings, wherein there is shown by way of illustration and not of limitation, a preferred embodiment thereof.

In the drawings:

Figure 1 is a side elevation of connecting switch constructed in accordance with this invention,

Figure 2 is a plan view of the switch shown in Figure 1 of the drawings,

Figure 3 is a fragmentary plan view of the switch shown in Figure 1, with parts broken away to show details of construction,

Figure 4 is a side elevation ofthe switch as shown in Figure 3 of the drawings, with another part broken away and in section to show the switch bladecounterbalancing means,

Figure 5 is a further enlarged fragmentary view showing the operating mechanism with the switch blade in its closed position,

Figure-6 is a view similar to Figure 5, showing the position of the operating mechanism when the contact pressure producing mechanism has been operated,

Figure 'I is a view similar to Figures 5 and 6, showing the position of the operating mechanism when the 'switch blade is in its fully opened position,

Figure 8 is a reduced sectionalized end view, taken along line XX of Figure 1, and

Figures 9 and 10 are fragmentary sectionalized views, respectively showing the contact pressure producing mechanism carried by the switch blade in its operative and inoperative positions.

a single pole dis- Reference is now made to Figures 1 and 2 of the drawings, wherein there is shown a single pole switch having a movable blade provided with a high contact pressure producing means similar to that described in a co-pending application, Serial No. 131,191, filed March 16. 1937, by August C. Schwager, and assigned to the assignee hereof. In. this connection it is to be understood that various other forms of high contact pressure producing means may be used with the operating mechanism contemplated by this invention, and while we have, for the purpose of illustrating the invention, shown only'one switch, it is to be also understood that any number of these switches may be combined and simultaneously operated for the purpose of interrupting a multiphase power transmission system.

As shown in these figures of the drawings, the

switch blade, designated by the numeral I0, is pivotally mounted upon a support ll carried by a stand of insulators l2 and is adapted to cooperate with. a stationary contact l3 carried by a similar'stand of insulators I4. Arranged in spaced relation with the stand of insulators l2 there is a third stand of insulators l 5. The stand of insulators l5, unlike the stands of insulators l2 and I4, is adapted to be turned about its vertlcal axis. At its upper end the stand of insulators l5 carries an operating member l6 that is adapted through a rod I! to move the switch blade l8 between its closed and open circuit positions, and to also operate the high contact pressure producing mechanism carried by the switch blade H], as will hereinafter appear. The upper end of the stand of insulators I5 is held in spaced relation with the stand of insulators I2 by means of two tubular spring enclosing members l8 which are supported by a bearing l9, and at its lower end this stand of insulators l5 has opposed lever arms 20 and 2| with which operating rods or links 22 and 23 respectively connect. trolled by any suitable power or hand operated switch operating means, as is well understood in the art. In order to provide for a maximum of clearance between the stands of insulators l2 and H, the stationary contact i3 is mounted upon an inwardly disposed support 24 carried by a cap 25 at the upper end of the insulator stand l4, and extending outwardly from the cap 25 there is a suitable terminal 26 to which one side of the power line may be connected. The other side of the power line is adapted to be connected to a terminal 21 located at the upper end of the 4 42 is provided with a sleeve 45 which extends stand of insulators l5.

From the above it will be readily seen that when the stand of insulators I5 is turned by the application of an operating force through the links 22 and 23, the operating member l6 will exert a force through the connecting rod l1 and cause the switch blade Hi to move in a vertical arc with respect to the stationary contact l3. to thus open and close the circuit between the line terminals 26 and 21.

Upon referring to Figure 3 of' the drawings, it

will, be noted that the switch blade I0 is carried by a forked supporting member 28 which is firmly clamped upon a transversely extending shaft 29 that is journaled at its ends upon the support II by means of bearings 30. Secured at its ends in good electrical contact with the forked ends ,of the supporting member 28 there is a. flexible ribbon-like conductor 3| which is clamped intermediate its ends, as at 32, to the end of a bus bar 33 that extends outwardly to the terminal 21 These operating rods 22 and 23 are con-' at the top of the rotatable stand of insulators I 5. This flexible conductor 3| and the bus bar 33 thus serve to provide-a low resistance path for the current passing through the switch blade I!) and avoids the transmission of any current through the bearings or other relatively moving parts of the switch mechanism. For the purpose of counterbalancing the weight of the switch blade l0 and its supporting member 28, the shaft 29 also carries two spaced bell crank levers 34 which are immovably secured upon the shaft 29 by means of set screws 35. One arm of each of these bell cranks, designated by the numeral 36, is connected firmly in any suitable manner to the switch blade supporting member 28, and the other arm of these bell cranks, designated by the numeral 31, projects downwardly to a point below and to one side of the axis of the shaft 29, where as shown in Figure 4 of the drawings, they are connected to a counterbalancing spring 38 which is enclosed within each of the aforementioned tubular spring enclosing members l8. As here illustrated, the tubular enclosing members l8 are secured at one end to the switch blade supporting member II, and at their outer'ends they are provided with an end closure cap 39. Each counterbalancing spring 38 is disposed concentrically about a guide rod 40 which is seated in a recess 4| formed in the end closure cap 39. At its other end the guide rod 40 is adapted, as the switch blade I0 is moved between its limits of travel, to slide freely in an adjustable tubular member 42 which is connected to the bell crank arm 31. The spring 38 is of the compressional type and is mounted between a spring seat 43 carried by the guide rod 40 and a collar 44 carried by the member 42, so that as the member 42 moves along the guide rod 40, when the switch blade I0 is opened and closed, the spring 38 will exert a force which will counterbalance the weight of the switch blade I0 and its supporting member 28 and thus relieve the operating member l6 and the connecting rod ll of any load due to the weight of these parts. As shown, the bell crank arms 31 are curved rearwardly from the axis of the shaft 29 so that as the Switchblade l8 approaches its'vertical position, the lever arm through which the counterbalancing spring 38 operates will be decreased, and thus the counterbalancing force exerted by the spring 38 will be reduced as the switch blade In approaches its vertical position. Since this arrangement requires that the counterbalancing spring 38 be of considerable length, the member substantially throughout the length of the spring 38 when it is in its compressed position.

Before proceeding further with the description of the invention, it will be observed in connection with the figures of the drawings previously described, that in addition to enclosing the coun-' terbalancing springs 38 in the housings l8 the switch blade supporting member I8 also carries an overhanging split housing having upper and lower halves 48 and 41 which serve to substantially completely enclose the switch blade'and high contact pressure means operating mechanism, which is to be presently described, In addition to the housing provided by the halves 46 and 41 and the enclosures l8 for thecounterbalancing springs 38, the design of the switch also includes semi-spherical caps 48 and 49 which extend over the universal connections at the ends of the operating rod l1 and similarly shaped caps 50 and ii which are disposed over the ends of the switch blade supporting shaft 29 The' puris adapted to abut. The adjustment ofthis set pose of these housings and the above semi-spherical caps, together with the general outline of the switch structure, which contemplates a rounded contour of all exposed parts, is to avoid sharp comers and projecting points from which a corona discharge might take place, as is generally the case with disconnecting switches operating at the higher voltages for which the switch of the present invention is principally designed.

Reference is now made to Figures 5, 6 and 7 of the drawings, forv a detailed description of the switch blade operating mechanism and the featurs thereof, which provide for an operation of the high contact pressure producing means by the operating member l5 independently ofmovement of the switch blade l and without loss of control of the switch blade by the operating member l6. As shown in these figures of the drawings, the connecting rod IT, in addition to a universal joint, is also connected at its other end by means of a similar joint to a yoke-like member 52 which is journaied at its ends upon the transuersely extending switch blade supporting shaft 29, where it straddles an adjustable cam plate or guide 53. This cam plate 53 is adapted to be secured'in a vertical plane centrally of andtransverse to the axis of the shaft 29 and is adjustable radially by means of a threaded stud 54 carried thereby which passes through a boss 55 upon the support II; The stud 54 carries a nut 55 that is adapted to clamp a rearwardly projecting end 51 of the cam plate 53 against shims 58 which are disposed between the portion 51 and the boss 55 upon the support H. The major portion of the cam plate 53 has an outer periphery 59 which is a true are concentric to the axis of the shaft {29, and at the lower end of this are 59 the cam 53 has a sharp inwardly inclined surface 80. Disposed on each side of the cam plate 53 and formed upon the yoke-like member 52 there are radially extend-- ing arms 6| which are joined at their ends be yond the limits of the cam plate 53 by a web 52 that carries links 53. The links 53 are pivot-Q ally connected to the web 52 by means of a transversely extending shaft 54, and at their outerend these links carry a similar shaft. 65 uponwhich there is journaled aroller 56 that is adapted to engage the cam surfaces 59 and 60 of the cam plate 53. In addition to carrying the roller 86, the'shaft 65 is also connected to a long arm 81' of a bell crank 58 journaled upon the switch blade operating member 28 by means of a shaft 59. Another and shorter arm of the bell crank 58, designated by the numeral 10, extends upwardly and is adapted to be connected by means of an operating connection 1| to the high contact pressure'producing mechanism at the end of the switch blade Ill. The longer arm 51 of the bell crank 58 also carries an adjustable set screw 12 which cooperates with an abutment 13 carried by the web 52 at the ends of the radial arms 65 is to maintain a contact between the roller 85 and the cam surface 59 upon the cam plate 53 as the switch blade is moved between its limits of travel, and thus insures a positive release of the contact pressure producing mechanism when the switch blade I0 is in all but its final closed circuit position; At the upper end of the arcuate surface 59 of the cam plate 53 there is a stop 14 against which an adjustable set screw 15 car-e ried by the being connected to-the operating member l by 6|. This set screw 12, when properly adjusted,

switch blade supporting housing 28 screw I5 is such that when the switch blade III has been moved into its closed circuit position, as shown in Figure 5 of the drawings, the roller 55 carried by the links 63 at the outer ends of 5 the radial arms 6| will be clear of the arcuate cam surface 59 and in a position where upon the imputation of a further operating. movementto the yoke-like member 52 by the operating rod II,

it will move overthe inwardly disposed surface 5|! upon the cam plate 53.

Theabove described movement of the .roller 68 over the inwardly disposed surface 60 of the cam plate 53 will, as illustrated in Figure 6 of the drawings, cause the longer arm 51 of the bell crank 58 to move inwardly with respect to the axis of the shaft 29, and as a result the other arm 10 of the bell crank 88 will move outwardly towards the end of the switch blade I0 and exert a force through the connection II which will operate the high pressure contact producing mechanism, as will be hereinafter described.

With the above described linkage connection between me yoke-like member 52 and the bell crank 68 carried by the switch blade l0 it will be noted that there is provided a permaneht positive connection between the switch blade operatingmechanism and the switch blade. It will also be noted that this linkage connection due to its association with the stationary cam 59,/is adapted to assume two different operative positions or conditions, in one of which it operates to connect the operating mechanism withthe switch blade to impart opening and closing movements thereto. and in the other of which it operates to connect the switch blade operating mechanism with the high contact pressure producing mechanism. At H the same time it should be'noted that this linkage at'all times provides apermanent connection between the switch blade operating mechanism and the switch blade in such a manner that 'control of the position of the switch blade is never lost by the switch blade operating mechanism. In this latter figure of the drawingsit will be noted that the switch blade ill with its supporting housing 28 is held against further downward or switch closing movement by means of the ad- J'ustable set screw I5 which has engaged the abutment 14 at the upper end of the cam surface 59, and that while the switch blade is held in this position the roller 66 has been caused to roll inwardly over the cam surface 50' of the cam plate 53. This is due to the additional movement of the radial arms 5! which is permitted by what age connection provided by the links 63 between the radial arms 6| of the yoke-like member 52 and the longer arm 810i the bell crank 68. When the parts are in this position it will-be noted that the shorter arm 10 of the bell crank 68 has to be moved to the left, or in a counter-- clockwise direction, to-operate the high contact pressure producing means at the end of the switch blade l0.

Figure 5 of the drawings. shows the condition of the switch blade and the high pressure means operating mechanism at the instant the switch blade ID has reached its final closed circuit position and before the high contact pressure pro* ducing means has been operated; and likewise this figure of the drawings also shows the condition of the operating mechanism at the instant that the switch blade l8 begins to move upwardly and into its open circuit position.

may be termed the variable character of the link- 55 Figure 6, of the drawings shows the condition that the roller 68 is still in contact with the arcuin its final closed circuit position and after the high contact pressure producing means has been operated to establish ahigh pressure contactbetween the end, of the switch blade Hi and the stationary contact i8 with which it cooperates. When the operating mechanism is in the condition illustrated inFigure 6 of the drawings, it will be readily seen that immediately upon the application of a switch blade opening force through theconnecting rod ll by a rotation of the operating member Hi, the yoke-like member 52 with its radial arms 8| will be rotated clockwise upon the shaft 28. This will cause the roller 68 to roll outwardly along the inwardly disposed cam surface 88 of the cam plate 53 and thus rotate the bell crank 68 in a clockwise direction to exert a reverse operating force through the connection H, which will release the high contact pressure producing means at the end of theswitoh blade I 8. After the roller 68 has been thus moved outwardly over the cam surface 88 of the cam plate 53, it will be free to move along the arcuate cam surface 58 of the cam plate 53 as the yoke-like member 52 with its radial arms GI and the switch blade l8 continue to move in a clockwise direction. During this clockwise movement of the switch blade I8 the roller 88 will continue to engage the arcuate cam surface 58 and hold the bell crank 68 in fixed relation with the high contact pressure-producing means at the outer end of the switch blade, as is clearly illustrated' in Figure 7 of the drawings, where it will be noted ate surface 58' of the cam plate 58 and the adjusting screw 12 carried by the bell crank arm 61 is in contact with the abutment 13 upon the web 62 which connects the ends of the radial arms SI of the yoke-like member 52. When the switch blade is in this latter position 'it will be noted that the members 42 which connect with the counterbalancing springs 38 have been extended out of the enclosing'housing l8 by the expansion of the springs 38. At this point the lever arm of the forces applied by the counterbalancing springs 88 will have been reduced to approximately one half of what it is when the switch blade I8 is in its horizontal or closed circuit position.

Referenceis now made to Figures 8, 9 and 10 of the drawings for a description of the high contact pressure producing means that has been chosen for the purpose of fully describing the present invention. producing means, as has been previously suggested, is fully described and claimed in the above referred to co-pending application filed by one of the joint inventors hereof, and in its specific form it is considered no part of the present invention, it being understood that the switch blade operating mechanism herein described is equally adapted to many other types of high'contact pressure producing devices.

- As shown in Figure 8 of the drawings, the stationary contact member l8 has two upstanding opposed contact forming surfaces 18 between which the end of the switch blade I8 is adapted to engage. The contact forming surfaces 18 are here shown as arranged in fixed spaced relation. This figure of the drawings also shows the switch blade ID as of tubular construction and as being split in a verticalplane through its center, as indicated at the points I1, so that the halves of the switch blade ill at each side of the split 11 may be expanded outwardly and into high This high contact pressure pressure engagement with the opposed contact forming surfaces I8 of the stationary contact I 8. The split 11 extends into the end of the switch blade l8 sufiiciently far to provide for the expansion necessary to produce a good contact.

In order to preclude the formation of high resistance oxides upon the contact surfaces 18 and upon, the contact engaging surfaces of the tubular switch blade l8, these contact forming surfaces may be provided with a silver plating or silver inserts, which are made as an integral part of the contact surfaces.

As shown in Figures 9 and 10 of the drawings, there is disposed within the tubular switch blade l8, and in proper cooperating relation with the split end I1 thereof, spaced supports 18, 18 and 80, which carry'oppositely positioned spring bars 8| and 82 that extend parallel, and at opposite sides of the split 11 in the end of the switch blade ID. The support I8 is of a continuous annular form, so that the spring bars 8| and 82 at this end will be held against outward movement, whereas the supports 18 and 88 are independent of each other and permit the outer ends of the spring bars 8| and 82 to move outwardly, as will hereinafter appear. The spring bars 8| and 82 are held at one end upon the support 18 by means of a pin 88 and a spacing collar 84, and at their other ends they are secured respectively upon the supports I8 and 88 by a similar free floating pin and a spacing collar 88. The spacing collar 88 is also shown as having an extension 81 into which a stud 88 is threaded. The stud 88, as will be clear from these figures of the drawings, serves through the medium of the compression spring 88 to yieldingly hold an end closure cap 88 upon the open end of the tubular switch blade I. The closure cap 88 has an inwardly projecting flange 8| which centers it upon the switch blade i8. Disposed in operative relation between the spring bars 8| and 82 there is an off-center link or toggle mechanism, by means of which a pressure may be exerted intermediate their ends to exert an outward expanding force within the split end of the switch blade 18 to bring the halves thereof into high pressure engagement with the opposed contact surfaces 18 upon the contact member [8. As illustrated, this off-center or toggle mechanism comprises a pair of spaced diagonally disposed links 82 which are pivotally secured approximately at the middle of the spring bar 82 by means of a strut 88 upon the end of which there is secured apin- 88 about which the links 82 pivot. 'Between .the free ends of the links 82 there is a clevis-like member 85 to which the operating connection H is attached, and between the forked end of this clevis-Jike member 85 I ber 88 also has a yoke-like construction which extends around the floating pin 88 and the spring bar spacing collar 84 so that it may move longitud inally with respect thereto.

there, -is a roller 88 which is adapted to roll into pres- As shown in Figure 9 of the drawings, it will be noted that when the contact pressure producing means is. operative, the spring bars 8| and 82 will be bowed out considerably, while at the same time the split end of the switch blade I8 has not been spread to any noticeable extent. However, in spite of the absence of a spreading of the switch blade l8, it will be understood that the pressure which is stored up in the bowed spring bars 8| and 82 is nevertheless being exerted through the sides of the switch blade, so as to create a high contact pressure with the opposed contact surfaces I6 of the stationary contact member- I3.

It is believed that the operation of a switch constructed in accordance with the above disclosure will be readily understood by those skilled in the art. However, by way of further explanation it may be stated that when the rotatable stand of insulators I5 is turned, as by the application of an operating force through the operating rods 22 and 23, the crank arm or operaing member I6 at the upper end thereof will exert a force through the connecting rod II to open and/or close the switch blade III with respect to the stationary contact I3, depending upon which direction the stand of insulators I5 is turned. If the switch blade I0 is in its open circuit position and an operating force is applied to the stand of insulators I5, the operating member I6 will exert a force through the connecting rods I I which will move the switch blade I0 downwardly into its horizontal position to bring its end into cooperating relation with the stationary contact I3. At this point of the switch closing operation, the operating mechanism will be in the position illustrated in Figure 5 of the drawings, where the adjustable-stop I5 is shown as in abutting engagement with the stop 14 car ried by the cam plate 53. This will, as suggested above, hold the extending end of the switch blade II! in cooperating relation with the stationary contact I3.

. Now, as a further operating force is applied through the connecting rod IT by the operating member I6, the yoke-like memb..-r 52 will be moved about the shaft 29 for a further distance to bring the parts of the operating mechanism into the positions illustrated in Figure 6 of thedrawings. During this latter movement of the yoke-like member 52, the radial arms 6| carried thereby will exert a force through-the links 63 which will cause the roller 66 to move inwardly over the cam surface upon the cam plate 53, and as a result the bell crank 58 will be rotated in a counterclockwise direction to the position illustrated in Figure 6 of the drawings, and thus the short arm III of the bell crank 68 will have been moved towards theend of the switch blade II] to operate the high contact pressure producing means, as will be hereinafter pointed out.

If it is now assumed that the switch is fully closed and in high contact pressure engagement with the stationary contact I3, and an operating force to open the switch is exerted upon the yoke-likemember 52-, through the connecting rod H, by the operating member I5, the yoke-like member will be rotated about the shaft 29 free of the switch blade I0 for a distance sufficient to move the roller 66 outwardly over the-cam surface 60 upon the plate-like member 53, and thus move the bell crank 68 in a clockwise direction upon its shaft 59 so as to release the contact pressure producing means at the end of the switch blade Ill. When this, initial movement of the yoke-like member 52 has been completed, the parts will be in the positions illustrated in Figure 5 of the drawings, and as a result a switch blade opening force will be transmitted from the yoke-like member 52 through the radial arms BI, the links 63 and the long arm 51 of thebell crank 68 to the shaft 69 which is carried by the switch blade supporting member 28. From this point on, further ,clockwise rotation of the yoke-like member 52 about the axis of the shaft 29 will cause the switch blade carrying member 29 and the switch blade I0 to be raised and moved out of cooperating relation with the stationary contact I3,

until the parts have reached the positions illustrated in Figure 7 of the drawings, when the switch blade III will be in its full open circuit position;

Reference is now made to Figures 9 and 10 of the drawings for a brief description of the operation of the contact pressure producing means chosen for illustration with this disclosure. As here shown, the connection 'II is attached to a yoke-like member 95 that is carried at the upper end of the two spaced links 92 and between which there is a roller 96. When the .parts are in the condition illustrated in Figure 10 of the drawings, the roller 96 will be inoperative, but

when the operating connection II is moved to the left, as by the previously described rotation of the bell crank 68, the roller 96 will be carried. upwardly in an are, due to the links 92, and as result the spring bars 8I and 82 will be bowed outwardly, as indicated in Figure 9 of the drawings, to exert a contact pressure producing force between the sides of the switch blade I0 and the surfaces 16 upon the stationary contact I3, the amount of this contact pressure being determined by the stiffness of the spring bars 8l and 82. With the above described arrangement it will be readily seen that unlike prior art switches, the

operation of the high contact pressure produc-- ing means at the end of the switch blade I0,

does not necessarily require a dead center or over center movement of the operating member I6 with respect to the axis of the switch, and as a result the operating mechanism hereinabove disclosed is more reliable in its operation, both with respect to the control of the switch blade and the high contact pressure producing means, than are switches of the type requiring the aforementioned dead center or over center operating relationship between the operating member and the center of the switch blade operating mechanism. While we have, for the sake of clearness and in order to disclose the invention so that the same can be readily understood, described and illustrated specific devices and arrangements, we desire to have it understood that this inven-- tion is not limited to the specific means disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and it is desired to claim it so that all such changes ascome within the scope of the appended claims are to be considered as part of this invention..

Having thus described our invention, what we claim and desire to secure by Letters Patent is: 1. In'an electric switch of the character described the combination of cooperating engageable contact members, a support upon which or e of said members is pivotally mounted, an operating member pivotally mounted in spaced relatinuously'connecting said actuating member with to provide a positive driving connection between said operating member and the pivotally mounted contact member and when in another position to provide an operating conection between said operating member and said actuating member, and a cam for controlling the position of said linkage connection, whereby said operating member will operate through said linkage connection to control the pressure applying mechanism at a predetermined relative position of said contact members without losing control oi! said pivotally mounted contact member.

2. An electric switch of the character described including cooperating engageable contact members, a support upon which one of said contact members is pivotally mounted, an operating member mounted in spaced relation with said support, a bellcrank mounted upon said support for movement about the pivotal axis and inde pendently of the pivotally mounted contact member thereupon, means connecting one end of said bell crank with said operating member, a contact pressure producing mechanism carried by the end of said pivotally mounted contact member for producing a high contact pressure between the contacting portions of said engageable contact members when in engagement, a

variable linkage connection between the other end of said bell crank and said pivotally mount- 7 ed contact member, said variable linkage connection being adapted to assume two operative positions in one of which it provides a positive driving connection between said bell crank and the pivotally mounted contact member and in the other position of which it permits relative movement between said bell crank and the pivotally mounted contact member'without loss of the connection between these members, means cooperating with 'said variable linkage connection adapted to control its condition of operation during the operation of the switch, and means controlled by said variable linkage connection when in-its latter condition adapted to operate said high contact pressure producing mechanism at the mounted contact member.

3. In an electric switch of the character described the combination oi, a stationary contact, a cooperating pivotally mounted contact member, a support upon which said latter contact member is pivotally mounted, an operating member mounted in spaced relation with said support, a bell crank mounted upon said support for movement independently '01 said pivotally mounted contact member, means connecting said operating member with one end of said bell crank for positively controlling the movement thereoi' about the axis of said pivotally mounted contact member, a separate mechanism carried by said pivotally mounted contact member for producing pressure between the engaging contact portions of said contact members, a, second bell crank pivotally mounted upon and movable with said pivotally mounted contact member and having a permanent connection at one end with said separate contact pressure producing mechanism of said pivotally mounted contact me ber, a linkage connection between the tree en of said first bell crank and the free end of said second bell crank, and a cam for controlling the operation of said linkage connection between said bell cranks, whereby said operating member will operate through said first bell crank to control the closing movement of said pivotally mounted contact member and subsequently operate through both ofsaid bell cranks to control the separate contact pressure producing mechanism at the end 01' said pivotally mounted contact member after the engageable contact members have been brought into cooperating relation and without at any time losing control of said pivotally mount- I ed contact member.

4. In an electric switch of the character described the combination of, a stationary contact, a pivotally mounted cooperating member, a support upon which said latter contact member is pivotally mounted, an operating member mounted in spaced relation with said support, a bell crank pivotally mounted upon said support and adapted for movement independently oi said pivotally mounted contact member, means connecting said operating member with one end of said bell crank for positively controlling the movements thereof, a pressure producing mechanism carried by said pivotally mounted contact member for producing a high contact pressure between the engaging contact portions of said contact members, a second bell crank pivotally mounted upon and movable with said pivotally mounted contact member and having a permanent connection at one end with the contact pressure producing mechanism 01' said pivotally mounted contact member, a linkage connection between the free ends 0! said bell cranks, and a cam associated with said linkage connection adapted to maintain an immovable relation between said first bell crank and the pivotally mounted contact member during the opening and closing movements thereof and permitting relative movement therebetween when said pivotally mounted contact member is in its closed position, whereby while said first bell crank may move relative to said pivotally mounted contact member said bell crank will be maintained in positive position controlling relation to said pivotally mounted contact member.

AUGUST C. SCHWAGER. ARNOLD E. BROCK. ROY H. GERARD.

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