US2345034A - Circuit interrupter - Google Patents

Description

March 28, 1944. HJ CRABBS 2,345,034

CIRCUIT INTERRUPTER Filed 0G13. 20, 1939 4 Sheets-Sheet l INVENTOR March 28, 1944. H. J. cRABBs CIRCUIT INTERRUPTER Filed Oct. 20, 1939 4 Sheets-Sheet 2 lsa sa f lN'vENToR Her-.6671 J'abb BY qnl' l/ATToRN WITNESSES: aw fw @M z M Malch 23, 1944. H. J. cRABBs n CIRCUIT INTERRUPTER A'rroRNw! March 28, 1944. H. J. cRABBs 2,345,034

CIRCUIT INTERRUPTER Filed Oct.' 20, 1939 4 Sheets-Sheet 4 Patented Mar. 28, 1944 CIRCUIT INTERRUPTER Herbert J. Crabbs, Wilknsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 20, 1939, Serial No. 300,368

(Cl. 21m-162) 27 Claims.

My invention relates generally to electric circuit interrupting devices, and more particularly to electric switches.

A primary object of my invention is to provide a switch of novel construction, which will have a longer life and be relatively easy to operate compared to switches known heretofore.

In relatively large capacity switches, the contact pressures are necessarily high, and considerable diiculty has been experienced in opening and closing such switches. Normally in opening switches of this type, a greater amount of force is necessary to start or break away the switch blade, especially if the switch has been closed for any length of time or if there is any corrosion present.

It has been proposed to provide some sort of force multiplying means effective to initially move the blade a short distance in its opening movement to assist in breaking away the blade, and it has further been proposed to make the break contacting portions of such switches of limited extent in the direction of opening movement of the switch, so that the switch blade may be substantially disengaged upon a relatively small movement.

Another object of my invention is to provide a novel limited contact arrangement for a blade type switch.

It is a further object of my invention to provide a blade type switch having a limited contact arrangement which is capable of -being entirely disengaged by force multiplying means.

A disadvantage of the use of force multiplying means for breaking open switches results from the fact that with the multiplication of force obtained, a corresponding diminishing travel results, hence such a means can be practically utilized only to move a switch blade extremely short distances, and thereafter direct application of the available force has been employed to complete the opening movement of the switch blade. inasmuch as these switches are usually manually operated, the available force is limited, and may be insuiiicient to easily complete the switch opening movement.

Consequently, another object of my invention is to provide a switch 4blade with a substantially frictionless movable mounting, so that the switch blade may be moved to full open position with a minimum of effort on the part of the operator.

Another object of my invention is to provide a switch hinge construction embodying frictionless limited area contactstructure.

Still another object of my invention is to provide a switch blade construction embodying limited area contact portions, so that different contact portions are relatively movable to permit more perfect engagement of the blade and tongue contact portions, and at the same time better distribute and equalize contact pressures.

In switches of the types embodying split blades, or split tongues, contact pressure is usually obtained :by passing a bolt or the like through the split member, and the bolt is tightened to stress spring washers provided theeron, any desired amount. This can be conveniently done at the hinge end of a switch where the bolt usually serves as the switch blade pivot. However, at

the break end of the switch, this construction requires cutting away of a portion of the break contact to accommodate the bolt.

Another object of my invention therefore, is to provide novel contact pressure means for a switch, which is intimately associated therewith.

Another object of my invention is to provide limited contact means for an electric switch, yieldingly mounted on parts of the switch.

These and other objects of my invention will become more apparent when considered in connection with the following description and attached drawings, wherein I have disclosed preferred embodiments of my invention:

Figure l is a front view of a disconnecting switch constructed in accordance with my invention;

Fig. 2 is a side view of the switch shown in Fig. 1;

Fig. 3 is a side elevational view of one of the sides of a split blade used in the switch shown in Figs. 1 and 2;

Fig. 4 is an enlarged cross-sectional view of the hinge end of the blade side shown in Fig. 3 and illustrating the initial formation of the blade for receiving a limited contact insert;

Fig, 4a is a view similar to Fig. 4 but showin the contact inserts in place;v

Fig. 5 is an end elevational view of the break end of the blade shown in Fig. 3;

Fig. 6 is a View similar to Fig. 5 but showing the blade before the inserts have been added;

Fig. 7 is across-sectional view of the break end of the switch shown in Figs. 1 and 2 and showing the blade slightly separated from the plane of the break tongue;

Figs. 8 and 9 are more or less diagrammatic views showing the blade and break tongue of the switch as shown in Figs. 1 and 2 at variousstages of engagement;

Fig. is a side elevational view of a switch similar' to that shown in Figs. 1 and 2 but showing a different operating mechanism for the blade, the parts being shown on a reduced scale;

Fig. l1 is a side elevational view of a modified form of disconnecting switch;

Fig. 12 is an enlarged partial cross-secticnal view taken along the line XII- XII of Fig. 11;

Fig. 13 is an enlarged partial cross-sectional view taken along the line XIII-XIII of Fig, 1l; and

Fig. 14 is a View similar to Fig. 12 showing a slightly modied form of limited contact structure.

In the form of my invention shown in Figs. 1 to 9, inclusive, and referring first particularly to Figs. 1 and 2, I have illustrated therein my invention embodied in a disconnecting switch mounted on a supporting base 6 by means of the vertically spaced insulators 2 and 4, respectively. The insulators 2 and 4 may be made of any desired insulating material, such, for example, as porcelain, glass, or the like. Suitably secured on the outer end of the cap piece for the insulator 2, as by the machine screws 6, I have provided an angularly extending support member I0 which is substantially T-shaped in cross-section. The support I0 includes the cross piece l2 and the intermediate stern or web portion te. Two sets of hinge tongues I8 are rigidly mounted on the support l0 by the horizontal spaced bolts i 6 which pass through apertures in the hinge tongues I8 and in the support I 0. The bolts I6 are secured in position by lock washers and nuts Il. Each hinge tongue I8 includes an intermediate straight tongue and spaced outer tongues 22 having upper straight portions which are suitably spaced from the intermediate tongue, 26 and lower portions bent inwardly as at 24 to be located closer to the intermediate tongue 26 to form' a terminal for the particular hinge tongue i8. Spacing sleeves are mounted on the bolts I6 between the tongues of each set, and spacing sleeves 21 are mounted on bolts I6 between the sets of tongues I8. A split blade 2B is provided for each hinge tongue I8. Each blade includes the spaced parallel blade sides 28 and 30. Each side has one end thereof received between the intermediate hinge tongue 2i] and an outer hinge tongue 22, and a threaded rod 32 extends through apertures in the upper ends of the hinge tongues and the adjacent ends of the blade sides 28 and 3S] of both blades 26. and is provided with resilient washer elements 33 positioned at the outer sides of each hinge tongue i8, which washer elements are initially stressed and maintained in such predetermined stressed condition by the nuts 34 on the threaded rod 32 and lock nuts 36. The blades 26 are provided with limited contacting portions Ail for engaging the adjacent surfaces of the hinge tongues which contact portions will be hereinafter described in greater detail.

The insulator 4 has mounted on its cap piece an angularly extending support 42 similar to the support i8. The support 42 is substantially T-shaped in cross-section and includes a head 44, and a stem or web portion 45. Bolts 4S pass through spaced apertures in -the upper end of the support and in the sets of break tongues 52, to rigidly mount the break tongues on the support. The bolts 48 are maintained in position by lock washers and nuts 5i). Each break tongue set 52 includes an intermediate straight tongue 54 and spaced outer tongues 56, the lower portions of which are straight and the upper portions beyond the bolt 48 being bent inwardly as at 58, to lie closer to the intermediate tongue 54 to serve as a terminal portion for the break tongue. The break tongues 54 and 56 are maintained in spaced relation by the tubular spacing member 49 mounted on the bolts 48, and they are maintained in spaced relation With respect to the other set of break tongues 52 by the tubular spacer member 5| mounted on the bolts 48 between the two sets of tongues 52. A threaded rod 66 extends through aligned apertures in the break tongues and has mounted thereon at opposite sides of each set of tongues 52, resilient washer elements 66 which are maintained under a predetermined stress by the nuts 62 engaging the washers which, in turn, are maintained in position by the lock nuts 64. The blades 26 are provided with inwardly opening notches 63 for receiving the vthreaded rod when the blade is in the closed position with respect to the break tongues 52.

Pivotally mounted on the blades 26 adjacent the break tongues 52 is a camming-out member '12, which is pivotally mounted on the pin 'I0 which extends through apertures in the blades 26 and is maintained in position by any suitable means, such, for example, as by Cotter pins or the like. The camming-out member 'l2 is substantially T-shaped in form and includes the stem or leg por-tion 14 extending in between the blades 26 and which has an eccentric aperture for receiving the pivot pin l0. The cammingout member 'l2 also includes a head or cross portion having enlarged ends 16 substantially Overlying each blade 26. The upper and lower edges i3 and '-'9 of the ends 'i6 form stops for limiting the pivotal motion of the camming-out member with respect to the blades 26. As stated before, the camming-out member 'l2 is pivotally mounted on an eccentric axis with respec-t to the blades 26 so as to provide a cam portion 80 on the intermediate stem 'I4 of the camming-out member '12, which is engageable with a xed cam member 82 formed integral with the support 42 The blades and break tongues are provided with limited area contacting portions as shown at 84 which are arranged to be entirely disengaged by a relatively slight separating movement of the blades 25 and the hinge tongues 52. The enlarged portions 16 of the camming-out member are spanned by an operating pin 8i to which a link of any desired suitable operating mechanism may be pivotally connected, for opening and closing the switch, or this pin 8l may be engaged by any suitable manually operable insulated cperating member, such, for example, as a hook stick operating member.

It will be clear, especially from Fig. 2, that if it is desired to open the switch, it is merely necessary to exert a pull on the camming-out member 'l2 in an outwardly, or downwardly direction to rotate the same in a general counterclockwise direction about its pivot pin 10. Due

to the relatively greater distance between the pivot pin 'lil and the operating pin 8l compared to the distance between the pivot pin 10 and the cam portion of the camming-out member 12, it is obvious that a greater mechanical advantage is thus obtained to initially break away and move the blades 26 a short distance away from the break tongues 52. The limited contacting portions on the blade and break tongues are arranged, as will be hereinafter described in detail, so that the mechanical advantage obtained by the camming-out member is used to entirely disconnect or disengage the contacting portions of the blades 26 and the break tongues 52. Thus, when the stop portion 18 of the camming-out member 'I2 is moved from the position shown in Fig. 2 until it engages the blades 26, the blade will be moved suiliciently to be entirely disengaged from the break contact, and thus the only opposition to the following application of direct force to move the blades to a wide open position, is merely the friction encountered at the hinge end of the blade.

As shown in Figs. 3, 4, and 4a, the hinge end of the blade is provided with ahinge pin aperture 86 and an annular raised contacting portion 40. This contacting portion 4|) is preferably in the form of an insert which is inserted in slots 88 formed in the blade. The inserts 40 are placed in the slots and secured therein by a pressing operation which separates a portion of the material of the blade adjacent the slot and bends it over the insert in what is ordinarily termed a swedging operation. This bent over portion of the blade is shown at 90 in Fig. 4a. The inserts 40 as shown in Fig. 4a preferably have their outer surfaces convex in form so as to obtain substantially line annular contact between the blades 26 and the hinge tongues |8. The inserts 40 may be of any suitable conducting material, but inasmuch as they are in the form of inserts, they are preferably made of a material which is better able to withstand the high friction due to the relatively high pressures exerted, especially in large capacity switches by resilient washers 38, and at the same time, they may be made of a material which is less susceptible to corrosion and may be of better conducting qualities than the material of the blades 26. The blades 26 are preferably formed of a suitable conducting material, such as copper or the like. The inserts 40, however, are preferably made of a noble metal, such as silver, or instead of being entirely made of such a. metal, they may be bimetallic in form with a base portion of a baser material, such, for example, as copper or the like with an outer coating of a noble metal.

It is believed obvious from the foregoing that the only contact between the blades 26 and the hinge tongues I8 will be substantially annular line contacts between the inserts 4|] on the blades and the contact tongues.

The break end of each blade is initially formed as shown in Fig. 6 with longitudinally extending slots 92. Straight inserts 84 are provided in the slots 92, which insertsI may be of the same construction and material as the inserts 48, and are secured in the slots 92 by a pressing or swedging operation in the same manner described in connection with the hinge end inserts 48. However, as seen particularly in Figs. and '7 to 9, the upper inserts in the break end of the blade extend laterally of the blade a greater `distance than the lower inserts 94. The break tongues 52 as shown in Fig. '7 are also provided with inserts which t into dovetailed grooves in the break tongues, respectively, with the upper insert 96 having its outer surface ush with the cuter surface of its respective outer break tongue, and the lower inserts 9B extend an appreciable distance beyond the contiguous sury and break tongue, while slightly separated, will appear as in Fig. 7. It is apparent that upon continued movement of the blade towards the break tongue from this position, because of the different lateral extent of the inserts both on the blade and tongues, these parts will not engage at all until they reach the position shown in Fig. 8, which is very near the full closed position, whereupon the upper contact inserts on the blade engage the upper ends of the break tongues, While the lower contact inserts on the blade are positioned to engage at the same time the lower inserts on the break tongue. Continued movement a relatively slight distance will bring the switch to the fully closed position illustrated in Fig. 9. It is thus apparent that in this embodiment of my invention, I have provided a disconnecting switch which requires but a relatively slight movement to entirely engage or disengage the break end of the blade from the break tongue, and this is accomplished furthermore by providing two contacting portions of the blade and break tongue in the closed position of the switch, which are spaced on opposite sides of the center line of the switch blade to provide a balanced structure while at the same time obtaining complete separation or engagement of the break tongue by a relatively slight movement of the blade relative to the tongue, which movement is entirely accomplished by the camming-out member before the stop portion 'I8 thereof engages the blade in the opening movement of the switch.

In Fig. 10 I have shown a disconnecting switch on a greatly reduced scale which is similar to that shown in Figs. l to 9, and having a blade 26 which instead of being operated by a camming-out member as is the case for the switch shown in Figs. l to 9, is connected for operation by a rotatable crank or toggle member |08 which is rotatably mounted at the point ||l| and has its free end pivotally connected to one end of a connecting or toggle link |82, which has its opposite end directly pivotally connected to the blade 26 as at |04. As

shown in this figure, in full lines. the parts are in the closed position of the switch; it will be apparent that the link |96 and link |02 form a toggle which then is at its dead-center point. In other words, the pivot points lill, |93 and |84 will be substantially aligned. It will, therefore, be apparent that only a relatively slight movement of the drive toggle link will be necessary to entirely engage or disengage the blade 26 and xed contact 52 and that this motion takes place closely adjacent to the dead-center position of the toggle. The dotted line position. of the parts in Fig. 10 indicates the position at which the contacting inserts on the blade and tongue, and hence the blade and tongue themselves will be entirely disengaged. Inasmuch as it is well known in the art that the greatest mechanical advantage for tending to move the link |92 longitudinally is obtained substantially at the deadcenter position of the toggle links |08, |02, it is apparent that I have here, too, provided force multiplying means for initially opening a disconnecting switch blade which is effective or which has its greatest eiect while the blade is being engaged or disengaged from the blade tongue and thereafter Ythe operating means is capable of moving the blade a greater distance relative to the movement of the primary operating member with a lesser mechanical advantage. It should be noted in connection with the embodiment shown in Fig. 10 that the greatest mechanical advantage of the blade operating mechanism is utilized, not only for opening the switch but also for closing the switch, this being contrasted to the cammingout feature of the operating means shown in Figs. 1 and 2 which is operable only to disengage` the blade from its cooperating break contact.

In Figs. 11 to 13 I have illustrated a slightly modified form of disconnecting switch which includes the supporting insulators |38 and ||l made of material similar to the insulators described in the first embodiment. The insulator has secured to its outer end as by the machine screws H9, a hinge tongue structure H2 which includes an integral laterally extending terminal portion I I4. A split blade I3 includes spaced blade sides |65 positioned on opposite sides of the break tongue H2 with each blade side |06 being composed ofA separate longitudinal portions ||5 and As shown more particularly in Fig. 13 the blade I I3 is pivotally mounted on the hinge tongue I i2 by means of the hinge bolt I I5 passing through the blade sides and hinge tongue and resilient washers |23 are located on the hinge bolt at the outer sides of the split bla de. A nut I8 is engaged with the bolt H5 to provide an initial stress on the resilient washers I 23. The washers |20 are provided with a peripheral inwardly extending flange |22 which ts in a corresponding groove in the outer surfaces of the blade ||3 to maintain the portions H5 and |i'| of each blade side in assembled relation. The outer sides of the hinge tongue I |2 andthe inner sides of each blade side IBS are provided with annular grooves for the reception of a plurality of conducting and bearing ball members |2I. These ball members |2| are preferably formed of any suitable conducting material such as copper or the like or they may be of noble metal such, for example, as silver. However, the preferred form is bimetallic with an inner core of a base conducting metal, such as copper, with a coating of a noble metal such as silver.

The insulator |38 carries at its outer end a break tongue |211 which includes a laterally extending terminal portion |25. The break end of the blade I i 3 is extended beyond the break tongue |2flto accommodate a combined latch release and camming-out structure, which includes an operating member I 28 pivotally mounted between the lower blade side portions I Il on the bolt |26, witha resilient strip |21 being secured by the bolt 22 on the opposite sides of the blade ||3. Each of the strips i2? has an upper inturned end v--fhich is freely received in an elongated aperture i2 formed in the upper blade side portions H5, to aid in maintaining the blade side portions I I5 and Si? against separation at this end of the switch. rlhe latch release and camming-out member 123 has an outer enlarged apertured portion |33 adapted to receive a hook stick operating member or the like, and includes an inner laterally extending latch operating and cam portion l'm The portion |32 extends laterally outwardly thi an aperture |52 in the rear blade side itt, s view-ed in Fig. 11, to be engageable with the inclined surface |34 on the latch |35 mounted the rear of the switch. The inclined surface |34 of the latch terminates in a shoulder or hook portion |53 which engages in the aperture |52 to maintain the blade locked in its closed position. The latch E35 is pivotally mounted at its lower on the pivot pin |38 which, in turn, is supported by the spaced pivot supports |33, integral with the break tongue structure |24. The latch |36 has an integral-laterally extendingvbearing portion |40 which is apertured to receive the pivot pin |33 and also functions to support a coil spring |42, which has one end |44 thereof engaging a fixed portion of the tongue, and the other end lll'thereof engages a knob |48 integral with the latch |36. The spring is stressed in a manner to constantly urge the latch |36 to a latching position with respect to the aperture 52 in the blade side.

In operating the switch or in moving it to open position from the position shown in Fig. 11, a book stick or other operating member is inserted in the aperture |30 o-f the member |28 and pull is exerted which will tend to move the member |38 in a clockwise direction about its pivot |26. This movement of member |28 will rst cause engagement of the cam portion |32 thereof with the inclined surface |34 of the latch, and cause rotation ofthe latch out of the apertures |52 against the action of spring |22. This movement of the latch continues until the hook portion |53 is removed from the aperture |52 at which time a stop portion |54 on the lower end of the latch engages a portion xed on the terminal |25 to stop the pivotal movement of the latch under the influence of the member |28. The cam portion |32 ofthe member |28 will at that time be at an intermediate position relative to the apertu1e`l52. From this point on, therefore, a pryingout or force-multiplying action is obtained by reaction of cam portion |32 on latch surface |34 for a short distance, or until the cam portion |32 reaches the other side of the apertures |52 in the blade, whereupon the operating lever |28 will go solid with the blade and the blade is then moved from such apartly open position to any desired Wide open position by a direct application of the available force. Obviously, in the closing movement of the switch the inclined surface |34 of the latch |35` will engage the inner edge of the blade H3 and be cammed out to ride along the outer surface of the blade until the blade reaches its closed position when the latch is free to move into the aperture |52 under the influence of the spring |42. As is the case with the switch shown in Figs. 1 and 2, no mechanical advantage is obtained in the closing movement of the blade in this form of my invention.

It is, therefore, obvious that I have provided in this form of my invention as in the form illustrated in Figs. l and 2 a relatively greater mechanical advantage for initially moving the blade a short distance in the opening movement of the blade, further opening movement of the blade being accomplished by a direct application of the available force.

Secured to the break contact |24 adjacent the insulator |38 are a pair of diverging arcing horns |53 (only one of which is shown) which are secured to the break tongue in any desired manner, such, for example, as by the bolt-S |58.

The break tongue structure of this embodiment of my invention is particularly shown in Fig. 12, wherein I have illustrated a pair of 1ongitudinally extending, outwardly flaring arms having their inner ends secured to the break tongue |24 in any desired manner, such, for example,` as by soldering, welding, or the like. The outer ends of the arm |63 are formed with inwardly convex portions |52 having a coating or layer |64 of suitable contacting material thereon, preferably of a noble metal such as silver or the like. The resilient arms |33 are preferably of any suitably 'resilient conducting material, such, for example, as a phosphor-bronze alloy. The lower blade sections ||1 are provided with limited contacting insert portions |12 secured ilush thereto, and adapted to be engaged by the contacts |64 in the closed position of the switch. The upper blade sections ||5 are provided with resilient contact supporting arms |66 similar to the arms |60 and include at their upper ends, inwardly convex contact portions |68 which may ,be covered or coated with a layer of suitable material similar to the material |64 on the lower contact supporting arms. The break tongue |24 is provided at its upper end with a limited contact |14 on the opposite sides thereof which may be in the form of inserts of a noble metal or at least a metal differing from that of the tongue.

It is obvious that the contacting portions of the blade and tongue in ,this form of my invention as in the form described in connection with Figs. 1 to 10 will be entirely engaged or disengaged by a relatively slight movement of the blade and here, too, the parts are so constructed and arranged that this slight movement is obtained entirely by the cam action or force-'multiplying action of the combined cam and latch release member |28. In Fig. 14 I have shown a slightly modiiied form of a disconnecting blade break end construction, wherein the resilient contact supporting members |80 and |86 on the break tongue and blade respectively are all located between the planes of the sides |06 of the blade. To accomplish this the .blade sides |06 are shown as being spaced slightly further apart than in the embodiment of Fig.` 12, but this construction has the advantage of insuring against accidental contact of portions of the blade and tongue, other than at the limited contact portions thereof. The resilient contact supports |80 and |86 are similar in structure to the supports |60. and |66 of the embodiment shown in Fig. 12. The supports |80 have outwardly convex contact supporting portions |82 which may have an outer coating or layer |84 of a noble metal secured thereto for engagement with the inserts |92 on the inner surfaces of the blades. The inserts |92 on the blade and inserts |94 on the tongue are similar to the inserts |14 and |12 shown in the embodiment of my invention shown in Fig. 12. The resilient supports |86 which are secured to the inner sides of the blade sides |06 have inwardly convex contact portions |88 which may have a contacting layer |90 on the outer side thereof. It is obvious that here, too, but a relatively slight movement of the blade relative to the break tongue is necessary to entirely connect or disconnect the blade and tongue, thus taking advantage of a cam construction such as that shown in Fig. l or 11 in the same manner as the contact structures shown in those gures. y

It should be noted that one advantage of a switch, such as is shown in Figs. 11 to 14, employing a split blade side |06 with the separate side portions ||5` and ||1, shown in these figures, is that where a plurality of points or lines of contact are used between the blade and the hinge and the break tongues, better alignment of the blade and tongues and better contact at the several points or lines is obtained, because the contacts of each of the blade 'side portionsY l5 and |1 are free to find their own contact. Thus,`as viewed in Fig. |2 any disalignment or bending of the contact supporting portions |66 and |60 will n ot result in any twisting of the blade which might cause -undesired, engagement of the blade proper and tongue, because each of the sections ||5 and ||1 may move laterally sideways with respect to each other to properly locate their contacting portions with respect to the cooperating contact portions of the .break tongue. Another advantage of this construction is readily apparent from an inspection of Fig. 11 where it is obvious that the entire width of the break tongue is available for engagement with the longitudinally extending limited contacts on the -blade tongue. This is not true of the constructions shown in Figs. 1 and 2, for example, where a bolt is provided extending through the tongue and interrupting one of the break contacting portions.

Another advantage of the construction shown in Fig. 11 resides in the ease of operation of this type of switch, which is especially important in connection with large heavy, high capacity switches, where relatively high contact pressures must be used. As previously stated, the camming-member |28 is designed to move the blade sunciently to entirely disengage the blade from the break contacts. all other movements of the blade being under the influence of a force, which is in effect directly applied to the blade. However, due to the particular construction of the hinge end of my switch shown in Fig. 11, this is not a disadvantage because the hinge is in reality, from one standpoint, a ball bearing hinge and the friction to be overcome in it will be relatively slight since it involves rolling ratherthan sliding frictional parts. This is an important feature, because even with the substantiallyannular line contact at the hinge end of a switch, such as is shown in connectionY with the embodiment of tions between the switch blade andfits hinge and break tongue, with the contacting portions at the break end ofthe switch being the sole engagement between the blade and break tongue, and being so constructed and arranged that the blade is entirely engaged with, or disengaged from, the break tongue by a relatively slight movement of the blade, which movement at least when opening the switch is accomplished by force-multiplying means, thus leaving only the friction of the hinge end of the blade to be overcome in other movements of the blade. Furthermore, I have provided in one embodiment of my invention a blade hinge construction which is materially easier to operate than what has been known heretofore, and in fact will be substantially frictionless. It is also apparent that in one embodiment of my invention I have disclosed an example of movement-multiplying means Vwhichhas its maximum effect or `mechanical advantage for moving a switch. blade ,the relatively rslight amount necessary togcompletely engage 'or disengage the bladefroin its break contaets/This blade Qperatmg means is leise effective fifi both the opening and closing movements of the switch. It is also apparentthat ,I4 have. provided v"in one embodiment'eoi", my .invention a 'novel' blade construction wherein'jthe bladeV is constructed with at least two entirely separate'seetions whin are provide better alignment of the blade and its hinge and break tongues, and also to relieve any stresses which might otherwise be set up in the blade or its tongues due to any disalignment of these parts.

Having described preferred embodiments of my invention in accordance with the patent statutes, I desire that it be distinctly understood that my invention is not to be limited to the particular embodiments disclosed therein, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modications may be made in the structures disclosed, without departing from the broad spirit and scope of .my invention. Therefore, I desire that my invention be not limited except by what is expressly set forth in the following claims.

, I claim as my invention:

. 1. In a switch, a blade member movable into and out of engagement with a Contact member, said members being of a good electrical conducting material, one of said members being split to `receive the other f said members, at least one of said members having limited area contact portions projecting from at least one surface thereof towards the confronting surface of the other member when said members are in engagement, with said contact portions on said one surface projecting different distances and arranged so that said contact portions engage said other member only when the switch is substantially closed.

2. In-a switch, a blade member movable into and out of engagement with a contact member,

said members being of a good electrical conducting material, one of said members being split to receive the other of said members, the other of said members having limited area contact p0rtions thereon projecting from opposite sides thereof, the portions on each side projecting different distances and arranged to engage said first member only when the switch is substantially closed.

3. In a switch, a blade member movable into and out of engagement with a contact member, said members being of a good electrical conducting material, one of said members being split to receive the other of said members, at least one of said members having on one side thereof spaced, parallel, limited area contact portions projecting from said one side towards the confronting surface of the other member when said members are in engagement, with said contact portions projecting diiTerent distances and arranged so that said contact portions engage said other member only when the switch is substantially closed.

4. In a switch, a blade member movable into and out of engagement with a contact member, said members being of a good electrical conducting material, one of said members being split to receive the other of said members, at least one of said members having spaced parallel limited area contact portions projecting frone one side thereof to engage the other member when said switch is closed;'said contact portions extending at an angle to the line of movement of said blade member and being spaced in the direction of said movement, the contacting portions nearest said other member projecting 'to a lesser extent than remotev contacting'portions, and projecting limited areacontact portions on said other member positioned to engage said first mentioned contacting portions of lesser extent in the closed position of theY switch, whereby no parts of said members are ever engaged except the contacting portions thereof in substantially the closed position of the switch.

5. In a switch, a blade member movable into and out of engagement with a contact member,

`said members being of a good electrical conducting material, one of said members being split to receive the other of said members, at least one of said members having spaced paralle1 limited area contact portions projecting from one side thereof to engage the other member when said switch is closed, said contact portions extending at an angle to the lineof movement of said blade member and being spaced in the direction of said movement, the contacting portions nearest said other member projecting to a lesser extent than remote contacting portions, vand limited area contact parts on said other member positioned to engage said contact portions, respectively, in vthe closed position of the switch with the contact part adapted to engage said contact portion of lesser extent, projecting from said other member, whereby said members are never engaged except when said contact portions and contact parts are in engagement, substantially in the closed position of the switch.

6. In a switch, a 'blade member movable into and out of engagement with a contact member, said members being of a good electrical conducting material, one of said members being split to receive the other of said members, at least one of said members having spaced elongated,epar allel, limited-area contacting portions on one side thereof spaced in a plane arranged at an acute angle to the plane'of movement of said blade means, and arranged so that said contacting portions engage the other of said members only when the switch issubstantially closed, and said contacting portion located between the sides of said split member at least in the closed position of said switch.

7. In a switch, a lblade member movable into and out of engagement with a contact member, said members being of'afgood electrical conductingmaterial, one of said members being split to receive the other of said members, said members each having on at least one side thereof elongated, parallel, limitedarea contacting portions spaced in the direction of movement of said blade member and offset laterally thereof and arranged to engage the other of said members only when the switch is substantially closed.

8. In a switch, a split break tongue, a blade mounted for movement into and out of engagement between the sides of said tongue, said blade and tongue being of Aa good electrical conducting material, and said blade and tongue Veach having on at `least one confronting side'thereof, limited area Contact portions spaced in the direction ofA movement of said blade member and oiset laterallythereof. I

9. In a switch; a split break tongue, a blade mounted for movement into and out of engage; mentbetween the sides of said tongue, said blade and tongue being of a good electrical conducting material, and said blade and tongue each having on at least one confrontingside thereof, elongated limited area contact portions spaced in the direction of movement of said blade member and offset laterally thereof and extending at an angle to the direction of movement of said blade.

l0. In a switch, a splitrb'rea'k tongue, fa blade mounted for movement into and out of engagement between the sides of said tongue, `said blade and tongue being of a good electrical conduct-L ing material, and saidblade having projecting limited area contact portions on each side thereof facing the sides of said tongue when said members are engaged, with the portions on each side proj ecting different distances.

11. In a switch, a blade member movable into and out of engagement with a contact member, said members being of a good electrical conducting material, one of said members being split to receive the other of said members, each of said members having a plurality of elongated limited area contact portions oiset substantially laterally of the line of movement of the blade and spaced in said direction of movement, and located relative to said members so that said portions are engaged only substantially in the closed position of the switch, and said members being out of engagement at all other positions of the switch.

12. In a switch, a split break tongue, a blade mounted for movement into and out of engagement between the sides of said tongue, said blade and tongue being of a good electrical conducting material, and said blade having projecting limited area Contact portions on each side thereof, with the portions on each side projecting different distances and with the portions on each side of the blade projecting the lesser distance being positioned on the blade closest to said tongue, and inwardly facing limited area contact parts on the sides of said tongue positioned to engage said last mentioned blade contact portions in the closed position of the switch.

13. In a switch, a blade member movable into and out of engagement with a contact member, one of said members being split to receive the other of said members, in spaced relation, and opposed limited area contact portions carried by each of said members, and said portions on each member positioned to engage the outer sides of the other member.

14. In a switch, a blade member movable into and out of engagement with a contactI member, one of said members being split to receive the other of said members, in spaced relation, and opposed limited area contact portions resiliently supported by each of said members for engagement With the other member.

l5. In a switch, a blade member movable into and out of engagement with a contact member, one of said members being split to receive the other of said members in spaced relation, said split member having opposed inwardly extending limited area contact portions for engaging the outer sides of said other member, and said other member having opposed outwardly extending limited area contact portions for engaging the outer sides of said split member.

16. In a switch, a break contact tongue, and limited area contact portions resiliently supported on opposite sides of said tongue and facing in opposite directions, said portions being spaced inwardly from the outer end of said tongue.

17. In a switch, a blade member movable into and out of engagement with a contact member, and each of said members carrying a resilient limited area contact spaced therefrom for engagement with the other of said members.

18. In a switch, a base, a break contact tongue member projecting outwardly from said base and having spaced limited area contact portions at least on one side thereof, with the innermost one of said portions projecting laterally beyond the outermost one of said portions.

19. In a switch, a iiat switch blade member of electrical conducting material having spaced, limited area contacting portions of different lateral extent on at least one side of said member.

20. A switch member having spaced limited area contact portions on one-surface thereof, at least one of which projects beyond said surface of said member and the other of said portions.

21. In a switch, a blade member movable into and out of engagement with a contact member, one of said members being split to receive the other of said members, at least one of said members embodying laterally spaced limited area contact portions, the sides of said split member including separate relatively movable portions for cooperation with said contact portions respectively, and means urging the sides of said split member towards each other, so that each of said separate portions may nd its respective contact.

22. In a switch, a split blade member pivotally mounted on a hinge tongue for movement into and out of engagement with a contact, said blade having spaced limited area contact points with said contact and hinge tongue, each side of said blade including separate longitudinal parts, and means for urging said blade sides towards each other, but permitting limited relative movement of adjacent blade parts.

23. In a switch, a split blade member pivotally mounted on a hinge tongue for movement into and out of engagement with a contact, said blade having spaced limited area contact points with said contact and hinge tongue, each side of said blade including separate longitudinal parts, and means for urging said blade sides towards each other including resilient means engaging openings in the outer sides of said blade for preventing sideways separation of said blade parts while permitting limited lateral movement thereof.

24. In a switch, a split blade member pivotally mounted on a hinge tongue for movement into and out of engagement with a contact, said blade having spaced limited area contact points with said contact and hinge tongue, each side of said blade including separate longitudinal parts, and means for urging said blade sides towards each other including resilient washers mounted on a bolt connecting said blade sides, said washers having inwardly extending portions extending into openings in the outer sides of the blade, for preventing undue separation of said blade parts.

25. In a switch, a blade member movable into and out of engagement with a contact member, one of said members being split to receive the other of said members in spaced relation, said split member having opposed inwardly extending limited area contact portions for engaging the outer sides of said other member, and said other member having opposed outwardly extending limited area contact portions for engaging the sides of said split member at points spaced from said inwardly extending portions at the closed portion of said switch, and said contact portions being confined between the planes of the sides of said spilt member.

26. In a switch, a blade member pivotally mounted on a hinge contact member for movement into and out of engagement with a break contact member, said members being of a good electrical conducting material, annularly arranged limited area contact means between said blade and hinge contact members, and at least one of said blade and break contact members having limited area contacting portions spaced in the direction of movement of said blade member and laterally thereof soas to be engaged only when the switch is substantially closed.

27. In a switch, a split blade member pivotally mounted on a hinge tongue for movement into and out of engagement with a contact, said blade having spaced limited area points of contact -with said contact, each side of said blade including separate longitudinal parts on which said limited area contacts are mounted, respectively, and means for urging said blade sides towards each other, but permitting limited rela- 5 tive movement of adjacent blade parts.

HERBERT J. CRABBS.

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