US2434315A

US2434315A - Electrical switch

Info

Publication number: US2434315A
Application number: US514629A
Authority: US
Inventors: Froland Olav
Original assignee: James R Kearney Corp
Current assignee: James R Kearney Corp
Priority date: 1943-12-17
Filing date: 1943-12-17
Publication date: 1948-01-13
Anticipated expiration: 1965-01-13

Description

Jan. 13, 1948. o. FROLAND ELECTRICAL SWITCH Filed Dec. 17, 1943 2 Sheets-Sheet 1 R a A J 3 2 2b 2 Z 7 w n a a w\/\\o v w I I i 7 0 o 3 5 7M n 5 a 7 7 J i 0 62 ,2 l5 ,6 66 I 68 56 J5 Z6 65 70 56 7 s7 24 5 3 Z 4/ I a 65 f z I Jan. 13, 1948. o. FROLAND 2,434,315

ELECTRICAL SWITCH Filed Dec. 17, 1943 2 Sheets-Sheet 2 41' TORI/E M Ouw FRouu/q Patented Jan. 13, 1948 ELECTRICAL SWITCH Olav Froland, St. Louis, Mo., asslgnor to James R. Kearney Corporation, St. Louis, Mo., a corporation of Missouri Application December 17, 1943, Serial No. 514,629

Claims.

This invention relates generally to electrical switches, and more specifically to electrical switches of the type comprising movably supported switch blades movable into and out of electrical contact with contact means so as to complete or interrupt electrical circuits in which the switches are interposed, the predominant object of the invention being to provide such an electrical switch with improved, rapidly operating means for quickly interrupting or breaking the circuit at a point remote from the contacts of the switch, with which the switch blade makes electrical contact, so as to protect said contacts, and the switch blade from the injurious effects resulting from arcing when the switch blade is drawn from the closed-switch position to the open-switch position.

Fig. 1 is a side elevation of an electrical switch equipped with the improved quick-break means of the present invention.

Fi 2 is a front elevation of the switch assembly illustrated in Fig. 1.

Fig. 3 is an elevation of the switch assembly illustrated in Figs. 1 and 2 when Viewed from the side opposite to that illustrated in Fig. 1.

Fig. 4 is an enlarged, fragmentary horizontal section taken on line 44 of Fig. 1.

Fig. 5 is a longitudinal section taken on line 55 of Fig. 4.

Fig. 6 is an enlarged, vertical section of a portion of the improved quick-break mechanism of the present invention.

Fig. 7 is an enlarged, cross-section taken on line 'I--'l of Fig. 5.

Fig. 8 is an enlarged, cross-section taken on line 88 of Fig. 5.

Fig. 9 is an enlarged, horizontal section taken on line 99 of Fig. 5.

Fig. 10 is a view similar to Fig. 5, but showing the switch blade and parts of the quick-break mechanism in positions different from the positions occupied by said parts in said Fig. 5.

Fig. 11 is a vertical section taken on the staggered line ll-Il of Fig. 10. s

Fig. 12 is a view partly in elevation and partly in section of a part of the quick-break mechanism of the present invention.

In the drawings, wherein is shown for purposes of illustration, merely, one embodiment of the invention, A designates generally the switch illustrated in Figs. 1, 2 and 3. The switch A comprises a suitable supporting member l on which are mounted a pair of insulators 2 and 3. The insulator 2 has fixed thereto a terminal member 4 which is provided with an upwardly projected extension 4' to which an incoming electrical conductor Ca is suitably connected, mechanically and electrically. Also, the insulator 3 has fixed thereto a terminal member 5 having a downwardly projected extension 5' to which an outgoing electrical conductor Cb is mechanically and electrically connected by suitable means. The terminal member 4 supports a contact structure 6 and the terminal member 5 supports a similar contact structure I, said contact structures 6 and I being each made up of a plurality of resilient rod or wire elements shaped in plan as is shown in Fig. 4.

The terminal member 5 is provided with spaced, forwardly projected extensions 8 which support a switch blade 9 for pivotal movement into and out of electrical contact with the contact structures 6 and I, said switch blade having clamped thereto a member Ill that has trunnions II associated therewith which are rotatably received .in openings formed in the extensions 8 of the terminal member 5. The terminal member 4, at the upper end of the switch A, is provided with extension means l2 to which is pivotally attached a switch blade latch I3 that is provided with a bifurcated outer portion having spaced legs shaped to engage projected elements l3 carried by the switch blade 9 so as to lock the switch blade in its closed-switch position. Also, the switch blade 9 has pivoted thereto a latch operating member M which is provided with spaced cam portions N that engage and elevate the outer portion of the latch [3, when the outer eye portion of the latch operating member I4 is moved downwardly, to disengage said latch from the elements l3 of the switch blade, so as to permit outward pivotal movement of the switch blade from the closed-switch position to the openswitch position.

Supported by the insulator 2 of the switch A is a quick-break mechanism which is designated generally by the reference character Q. said quick-break mechanism including a member l5 from which an integral arm I6 is extended. the member I5 and the arm l6 being formed of electrical conducting material and said arm is suitably secured to said insulator 2 in electrical contact with the terminal 4 (Fig. 4). The member i5 supports a tubular element ll formed of suitable electrical insulating material, said member l5 being of annular, cup-shaped formation and an end portion of the tubular element I1 is seated in said member with a body of cement l8, or other suitable material (Fig. 6), being provided to rigidly secure said tubular element to said member I5, At the end of the tubular element opposite to the end thereof at which the member I5 is located, said tubular element has secured thereto a housing I9 which is formed of electrical conducting material, this housing having an annular cup-shaped portion 20 into which the forward end portion of the tubular element H is extended, and a body of cement 2|, or other suitable material, being provided to rigidly secure said housing I9 to said tubular element IT. The housing I9 is of the shape illustrated to good advantage in Figs. 4, 5, and 11; that is to say, said housing is provided with a top wall, opposed side walls, and a bottom wall having a downwardly projected extension l9, said housing l9 having an opening 22 formed in a side wall thereof and this opening is closed by a plate 23 (Fig. 11) which is suitably secured in place. Also, the housing I9 is provided with a rear wall 24, that forms a part of the cup-shaped portion 20, and through which rear wall a centrally located opening is formed. Likewise, the housing includes a forward end wall which is provided with a centrally located opening that is covered by a plate 25.

Secured to the member |5 of the quick-break mechanism Q is an element 26 (Fig. 6) which is formed of electrical conducting material and comprises an annular portion provided with an outstanding, annular flange 26' having apertures through which fastening devices pass for securing said element 26 to the member IS. The element 26 supports a rearwardly extended tubular structure 2! which is closed at its rear end by a closure element 28, the forward end portion of said tubular structure embracing the annular portion of the element 26 and fastening devices 29 being employed for rigidly securing said tubular structure to said element 26. The tubular structure 21 comprises an outer tube formed of insulating material which possesses sufficient mechanical strength and good weather-resisting qualities, and an inner lining tube which preferably is formed of horn fiber, or other suitable material, which is characterized by the ability to give off gas in the presence of the heat of an electrical arc which tends to extinguish the arc. The tubular structure 21 is provided at its bottom with an elongated slot 30 which extends longitudinally of said tubular structure and provides for the escape of gas from the chamber within said tubular structure during operation of the quick-break mechanism.

Screwthreadedly connected to the element 26, as shown to good advantage in Fig. 6, is a tubular, coupling member 3|, said coupling member having an internally screwthreaded end portion which is screwed into a screwthreaded opening 32 of said element 26. At its opposite end the coupling member 3| is internally screwthreaded and screwed into said internally screwthreaded end portion of said coupling member 3| is-a tubular structure 33. The tubular structure 33 comprises an outer tube 34 which is formed of electrical insulating material possessing the required mechanical strength, and an inner tube 35 formed of horn fiber, or other material, characterized by the ab lity to give off gas in the presence of the heat of an electrical are which tends to extinguish the arc. The tubular structure 33 which extends through the tubular element l1, abuts at one end with an inwardly projected, annular head 36 formed within the coupling member 3|, and at the opposite end of said tubular structure 33 the tube 34 abuts against the rear face of the wall 24 of the cup-shaped portion 20 of the hous ing is, the extreme forward end portion of the inner tube 35 being seated in the centrally located opening formed through said wall 24.

Arranged within the housing l9 and extended longitudinally thereof, is a pair of spaced, substantially parallel rods 31, the opposite ends of said rods being supported, respectively, by the wall 24 and the forward wall of the housing l9 by being provided with end portions which are seated in apertures in said walls of the housing. The spaced rods 31 support for guided, straight-line, sliding movement with respect thereto a head 38 from which is extended in a rearward direction a rod 39 formed of electrical conducting material, said rod 39 being provided with a forward portion 39' of reduced diameter which is extended into an opening formed in the head 38 and is secured therein by a pin 40 (Fig. 12). At its opposite end the rod 39 has fixed thereto a follower 4| which preferably is formed of horn fiber or other suitable electrical insulating material, that is so characterized as to give off gas in the presence of the heat of an electric are which tends to extinguish the arc. The follower 4| preferably is of substantially the same diameter as the rod 39, and it is secured to the rod by having a reduced end portion 42 of the rod forced into an opening formed in an end portion of the follower (Fig. 6).

By referring particularly to Fig. 6 of the drawings, it will be noted that the tubular element 26 has fixed thereto a contact 43 which includes an annular flange portion 44 that is secured to the tubular element 26, at the rear face thereof, by fastening devices 45. Extending forwardly from the flange portion 44, and projected through the central opening of the element 26 is a tubular contact portion 46 which is provided with circumferentially spaced and longitudinally extended slits that extend from the forward edge of the tubular contact portion 46 to a point spaced rearwardly of said forward edge. These slits provide the tubular contact portion 46 with a plurality of resilient contact fingers 41 that are provided with inwardly curved and outwardly flared portions which contact, during different phases of the operation of the quick-break mechanism, with the rod 39 and with the follower 4|.

Supported within the lower portion of the downwardly extended portion l9 of the housing |9 is a rod 48 which provides pivotal support for a lever structure 49, said lever structure comprising a hub portion 49a from which is extended a pair of spaced arms 49b. At their upper ends the arms 49b have pivoted thereto a pair of links 50, said links being disposed at opposite sides of the head 36 and the ends of the links, opposite to the ends thereof which are pivoted to the arms 49b, being pivotally connected to said head 38. The arms 49b of the lever structure 49 have extended from one to the other thereof an integral portion 5|, an extensible and contractile coil spring 52 being attached at one of its ends to said lever portion 5| and at its opposite end to the forward wall of the housing IS. The coil spring 52 tends to move the lever and link assembly 49- 50, and the head 38, to the positions that such parts occupy in Fig. 10.

Supported for rotary movement by bearing portions 53 (Fig. 11) formed on the opposed side walls of the housing |9 of the quick-break mechanism Q is a shaft 54 which extends transversely of said upper portion of said housing and extends outwardly beyond the housing. The portion of the shaft 54 which is located within the housing I! has fixedly mounted thereon a toggle link 55,

said toggle link being provided with a hub portion 55' that embraces said portion of the shaft 54 and is pinned or otherwise secured thereto. At its opposite end the toggle link is bifurcated so as to pivotally receive an end portion of an associated toggle link 58, the opposite end of said associated toggle link 56 being pivotally attached to the lever structure 49 at the location of the portion thereof. The toggle link 55 is provided with an extension 55' (Figs. '5 and which serves as an abutment element that contacts with the lower face of the top wall of the housing-l9 so as to arrest rotary movement of said toggle link 55 in one direction. Mounted on the shaft 54, at the outer end thereof, is an actuating member 51, which is shaped as is shown to the best advantage in Fig. 3, said actuating member having a cam face 51'51a which serves an important function that will be hereinafterv referred to in detail. The actuating member is preferably formed of electrical insulating material and it includes a hub portion 58 (Figs. 4 and 11) that embraces the shaft 54 and is suitably secured thereto.

Secured to the switch blade 9 of the switch A is an arm 59 that is provided with a clamping portion 69 (Fig. 9) which embraces the switch blade and is clampingly secured thereto by a bolt iii. The opposite end of the arm 59 is provided with a portion 62 through which an opening 62 is formed, said opening extending, also, through a portion of an extension 63 that is formed on said arm portion 62. Fixedly disposed in the opening 52 of the arm portion 62 and the extension 63 is the lower portion of a rod 64, said rod being extended upwardly from said arm 59 in substantial parallelism with respect to the switch blade 9 and being provided with anupper, bifurcated portion 55 that rotatably-supports a roller 65 (Fig. 10). Also, the extension 63 of the arm 59 has secured thereto, by means of the fastening devices 61, an auxiliary switch blade 88, which is arranged as is shown in Fig. 10. During operation of the switch blade 9. of the switchA, into and out of the closed switch p0sition,-the auxiliary switch blade 68 movesinto and out of electrical contact with anauxiliary contact structure 69 (Fig. 4). This auxiliary contact structure 69 comprises a pair of elongated strips of resilient, electrical conducting material, which are spaced apart slightly and "are secured to electrical conducting extensions I9 that are projected outwardly from an adjacent side wall of the housing IS. The elongated strips which produce the auxiliary contact 69 are flaredat their forward ends, as is shown in Fig.- 4, so that the auxiliary switch blade 68 may pass freely between said elongated strips when the switch blade 9 is moved to the closed-switch position.

In describing the operation of theswitch disclosed herein, it will be assumed that the switch is in the closed-switch position, as is shownin Figs. 1, 2, 3, 4, and 5, and that it is desired to operate the switch to the open-switch position. When the switch is in the closed-switch position the Switchblade 9 is, of course, in contact with the upper contact structure '6, and also, the auxiliary switch blade 68 is in contact with'the aux iliary contact structure 99, a portionfof said auxiliary switch "blade being interposed between the elongated strips of said auxiliary contact. There fore, when the switch is inthe closed-switch position the electrical path through the switch is from the conductor Ca, through the upper terminal member 4 and the contact structure 6 associated therewith, through the switch blade 9 to 6. the lower contact structure I and the, lower terminal member 5 with which said lowercontact structure is associated, and from the switch by way of the conductor Cb.

To move the switch blade 9 to the open-switch position the eye portion of the latch operating member I4 is engaged by a switch stick, and said eye portion is drawn downwardly so as to cause the forward portion of the latch l3 to be elevated out of engagement'with respect to the elements H" of the switch blade 9, whereupon the upper portion of said switch blade 9 is drawn outwardlyand downwardly out of electrical engagement with respect to the contactstructure 6. As the upper portionof the switch blade 9 moves out of contact with respect to the upper contact structure 6, electrical contact between said switch blade and said contact structure is broken, but no arcing occurs at said upper contact structure because the auxiliary switch blade 88 is still in electrical contact with the auxiliary contact structure 69. Therefore, when electrical contact between the'switch blade 9 and the contact structure 6 has been broken, as described above, the electrical path through the switch will be from the conductor Ca, throughthe upper terminal member 4, through the arm l6 of the quickbreak mechanism Q to the member 15, element 26, and contact 43 (see Fig. 6). The contact 43 makes electrical contact with the movable conducting rod 39 of the quick-break mechanism, and therefore electrical energy will flow from said contact 43 through said rod 39 to the traveling head 38. The head 38 has electrically connected to itat I0 an end portion of a length of flexible cable 'H which is loosely attached to one of the links 59 and to one of the arms 49b of the lever structure 49 by means of suitable clips 12, the opposite end portion of said length of cable being electrically connected to a wall of the housing I9 of the quick-break mechanism at the point designated by the reference character 13. From the housing l9 the path of the electrical energy is through the auxiliary contact structure 59, through the auxiliary blade 68, through the arm 59 and the switch'blade 9 tothelower terminal member 5 and the conductor Cb.

When the electrical path through-the switch is constituted as just described, the movable unit 50- made up of the head 38, rod 39, and follower M,

is positioned as shown to good advantage in Figs. 4 and 5, at which time the coil spring 52 tends to move said unit forwardly to the position in which it is shownin Fig. 10. However, the coil spring 52 is prevented from so moving the unit referred to because of the fact that the pivot 56 of the toggle produced by the toggle links 55 and 58 is over dead center with respect to the center of the shaft54 and the center of the pivot element which pivotally connects the toggle link 56 to the lever structure 49. As a result of this sit-'- uation the lever structure 49 is locked against pivotal movement in response to pull exerted by the coil spring 52 and the unit made up of the head 38, the rod 39, and the follower 4| is locked in the position inawhich said unit is shown in FigsAandS. a

Now, as the switch blade 9 continues to move outwardly and downwardly at its upper end'with respect to the contact structure 6, the roller 66, carried by-the rod 64 fixed to said switch blade 9, moves in contact with the cam face 51 of the actuating member 51, and when said roller engages the portion 5'la of said cam face the actuating member 51 will be rotated because-of such moving engagement of the roller with respect to said cam face portion. The actuating member I! is fixed to the shaft 54 as is the toggle link II, and therefore rotation of said shaft I4, because of the rotation of the actuating member 51, will break the toggle provided by the toggle links 55 and it forwardly and downwardly. The coil spring I! will then move the unit comprised of the head 8|, the rod 39, and the follower ll, rapidly in a forward direction to move the conducting rod 39 out of contact with the contact 48, thus breaking the electrical path through the switch and permitting continued forward movement of the outer portion of the switch blade 8 to draw the auxiliary switch blade I! out of contact with respect to the auxiliary contact structure 69 without arcing. It is to be noted that when the conducting rod 39 of the quick-break mechanism Q moves forwardly in response to pull exerted by the coil spring 82, as described above, any are formed because of the breaking of electrical connection between said conducting rod 3! and the contact 43 will be stretched or elongated as the conducting rod moves forwardly. Also, because the follower ll moves forwardly with the conducting rod 39 such elongated arc will be largely confined between the outer surface of the follower 4i and the inner face of the inner tube which surrounds the follower when it has moved forwardly. The follower 4| and the tube are formed of horn fiber, or other suitable material which gives of! gas in the presence of an electrical are that tends to extinguish the arc, and hence the arc will be extinguished, the gas so produced escaping through the slot 30 of the tubular structure ll.

When the switch blade 9 is moved from the open-switch position to the closed-switch position the operation just described is reversed. In other words, the inward movement of the switch blade 8 causes the auxiliary switch blade II to move into contact engagement with the auxiliary contact structure 58 between the elongated strips thereof. Also, the roller 86 carried by the switch blade 9 will engage the cam face 51' of the actuating member 51, which actuating member is at that time positioned as shown in Fig. 10, to rotate said actuating member and the shaft 54, on which it is fixedly mounted, so as to move the lever structure 49 rearwardly by force applied through the toggle links 55 and 56. Such movement of the lever structure 49 moves the unit made up of the head 38, the conducting rod 39, and the follower rearwardly to the position in which said unit is shown in Figs. 4 and 5, the pivot 58' of the toggle provided by the toggle links 55 and 50 being moved beyond dead center to lock said toggle and maintain the unit referred to in its rearward position where it is ready for another switch opening operation, and the upper portion of the switch blade 9 is moved into locked contact engagement with the contact structure 8.

I claim:

1. An electrical switch comprising a contact structure, a switch blade supported for movement into and out of contact engagement with respect to said contact structure, a quick-break mechanism comprising a contact member, a movably supported conducting element in the form of a rod arranged for movement into and out of electrical contact with respect to said contact member, spring means which tends to move said movable conducting element out of contact engagement with respect to said contact member, toggle means for moving said movable conducting 8 element into contact engagement with said contact member, said toggle means being movable to such position that the elements thereof because of their relative positions lock said movable conducting element in contact engagement with respect to said contact member, a single means actuated by movement of said switch blade out of the closed-switch position for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and actuated by movement of said switch blade into the closed-switch position for moving said movable conducting element into contact engagement with said contact member, said single means comprising a pivotally supported actuating member operatively related to said toggle means and having an elongated cam face, and means carried by said switch blade which engages a part of said cam face of said pivotally supported actuating member on switch-opening movement of said switch blade for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and which engages another part of said cam face of said pivotally supported actuating member on switch-closing movement of said switch blade for moving said movable conducting element into contact engagement with said contact member.

2. An electrical switch comprising a contact structure, a switch blade supported for movement into and out of contact engagement with respect to said contact structure, a quick-break mechanism comprising a contact member, a movably supported conducting element in the form of a rod arranged for movement into and out of electrical contact with respect to said contact member, spring means which tends to move said movable conducting element out of contact engagement with respect to said contact member, toggle means for moving said movable conducting element into contact engagement with said contact member, said toggle means being movable to such position that the elements thereof because of their relative positions lock said movable conducting element in contact engagement with respect to said contact member, a single means actuated by movement of said switch blade out of the closed-switch position for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and actuated by movement of said switch blade into the closed-switch position for moving said movable conducting element into contact engagement with said contact member, said single means comprising a pivotally supported actuating member of angular formation operatively related to said toggle means and having an elongated cam face, and means carried by said switch blade which engages a part of said cam face of said pivotally supported actuating member on switch-opening movement of said switch blade for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and which engages another part of said cam face of said pivotally supported actuating member on switch-closing movement of said switch blade for moving said movable conducting element into contact engagement with said contact member.

3. An electrical switch comprising a contact structure, a switch blade supported for movement into and out of contact engagement with respect to said contact structure, a quick-break mechanism comprising a contact member, a movably supported conducting element in the form of a rod arranged for movement into and out of electrical contact with respect to said contact member, spring means which tends to move said movable conducting element out of contact engagement with respect to said contact member, toggle means for moving said movable conducting element into contact engagement with said contact member, said toggle means being movable to such position that the elements thereof because of their relative positions lock said movable conducting element in contact engagement with respect to said contact member. a single means actuated by movement of said switch blade out of the closed-switch position for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and actuated by movement of said switch blade into the closedswitch position for moving said movable conducting element into contact engagement with said contact member, said single means comprising a pivotally supported actuating member of angular formation operatively related to said toggle means and having an elongated cam face having angularly related cam face parts, and means carried by said switch blade which engages a part of said cam face of said pivotally supported actuating member on switch-opening movement of said switch blade for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and which engages another part of said cam face of said pivotally supported actuating member on switch-closing movement of said switch blade for moving said movable conducting element into contact engagement with said contact member.

4. An electrical switch comprising a contact structure, a switch blade supported for movement into and out of contact engagement with respect to said contact structure, a quick-break mechanism comprising a contact member, a movably supported conducting element in the form of a rod arranged for movement into and out of electrical contact with respect to said contact member, spring means which tends to move said movable conducting element out of contact engagement with respect to said contact member, toggl means for moving aid movable conducting element into contact engagement with said contact member, said toggle means being movable to such position that the elements thereof because of their relative positions lock said movable conducting lement in contact engagement with respect to said contact member, a single means actuated by movement of said switch blade out of the closed-switch position for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and actuated by movement of said switch blade into the closedswitch position for moving said movable conducting element into contact engagement with said contact member, said single means comprising a pivotally supported actuating member of angular formation operatively related to said toggle means and having an elongated cam face having angularly related cam face parts, and means carried by said switch blade including a rotatable element which engages a part of said cam face of said pivotally supported actuating members on switch-opening movement of said switch blade for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and whiih engages another part of said cam face of said pivotally supported actuating member on switchclosing movement of said switch blade for moving said movable conducting element into contact engagement with said contact member.

5. An electrical switch comprising a contact structure, a switch blade supported for movement into and out of contact engagement with respect to said contact structure, a quick-break mechanism comprising a contact member, a movably supported conducting element in the form of a rod arranged for movement into and out of electrical contact with respect to said contact member, spring means which tends to move said movable conducting element out of contact engagement with respect to aid contact member, toggle means for moving said movable conducting element into contact engagement with said contact member, said toggle means being movable to such position that the elements thereof because of their relative positions 1001: said movable conducting element in contact engagement with respect to said contact member, a single means actuated by movement of said switch blade out of the closed-switch position for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and actuated by movement of said switch blade into the closedswitch position for moving said movable conducting element into contact engagement with said contact member, said single means comprising a pivotally supported actuating member of angular formation operatively related to said toggle means and having an elongated cam face having angularly related cam face parts, and means carried by said switch blade including a roller which engages a part of said cam face of said pivotally supported actuating member on switch-opening movement of said switch blade for releasing said movable conducting element for movement out of contact engagement with respect to said contact member, and which engages another part of said cam face of said pivotally supported actuating member on switch-closing movement of said switch blade for moving said movable conducting lement into contact engagement with said contact member.

OLAV FROLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,286,131 Wallace et al. June 9,1942 2,344,113 Schultz Mar. 14, 1944 2,272,717 Ludwig et al. Feb. 10, 1942 ,308,026 Rawlins Jan. 12, 1943 2,323,241 Richardson et al. June 29, 1943 773,467 Bradshaw Oct. 25, 1904 2,351,826 Lindell et al June 20, 1944 982,100 Smith Jan. 17, 1911 FOREIGN PATENTS Number Country Date 681,438 Germany Sept. 22. 1939