US2548280A

US2548280A - Electric switch

Info

Publication number: US2548280A
Application number: US97164A
Authority: US
Inventors: William J Allan
Original assignee: Missouri Automatic Control Corp
Current assignee: Missouri Automatic Control Corp
Priority date: 1949-06-04
Filing date: 1949-06-04
Publication date: 1951-04-10
Anticipated expiration: 1968-04-10

Description

April w, 195l w. J. ALLAN 2,548,280

ELECTRIC SWITCH Filed June 4. 1949 Patented Apr. l0, 1951 i ELECTRIC SWITCH William J. Allan, Richmond Heights, Mo., assignor to Missouri Automatic Control Corporation, St. Louis, Mo., a corporation of Missouri Application June 4, 1949, Serial No. 97,164

Claims. l

This invention relates to electric switching devices and more particularly to snap action switches of the self return type.

An object of the present invention is to provide a novel switching mechanism having mechanical snap action accomplished by the stressing of resilient members and in which contact bounce, heretofore characteristic in switches of this type, is obviated.

A further object is the provision of a snap action switch employing a toggle mechanism in which the linear motion developed by the toggle mechanism is applied in the direction of movement of the switch contacts and in which the toggle mechanism provides a lock against bounc-V ing of the contacts as they are rapidly engaged.

Further objects and advantages will become apparent when reading the following description in connection with the accompanying drawing.

In the drawing,

Fig. 1 is a plan view of a switching device constructed in accordance with the principles of the present invention;

Fig. 2 is a longitudinal sectional view' of the switch shown in Fig. l and is taken on line 2-2 of Fig. l;

Fig. 3 is also a longitudinal sectional view of the switch shown in Fig. 1 taken on line 2-2 of Fig. l, but showing the switch elements in different operative positions;

Fig. 4 is a right end or rear elevation of the switch shown in Fig. l;

Fig. 5 is a transverse sectional view of the switch shown in Figs. l and 2 and is taken on line 5--5 of Fig. 2;

Fig. 6 is a view of one of the toggle links shown apart from the switch structure;

Fig. 7 is a fragmentary view of one of the switch blades showing the notches therein into which one end of the toggle link shown in Fig.

6 is fitted. The view is taken on line 'I--T of Fig.

2 the toggle link itself being omitted;

Fig. 8 is a front end view of the other toggle link showing the notches therein into which is fitted the other end of the toggle link shown in 7 Fig. 6. The view is taken on line 8-8 of Fig. 2

l II and I2 of conductive material. The blades II and I2 are formed at right angles at their lowerA However,

ends and are clamped between plates I3 and I4 respectively and the base I0. The switch blades and plates are rigidly attached to the base by rivets I5 and Ia.. The rivets Ia. are tubular rivets internally threaded to receive screws |512 which provide suitable terminal means for detachably connecting conductors. The plate I3 has an upwardly formed portion I 6 lying parallel to the blade II, in which is threadedly engaged an adjustment screw Il, the projecting end of which engages the switch blade II. Suitably attached to the upper ends ofblades II and I2 are Contact members IB and I9 respectively. The blades II anduIZ are both resilient. The blade I2, however, is substantially more resilient than the blade I I as is indicated by its relative thinness.

Also mounted 4on the base I0 and toward .the right or rear end thereof and attached thereto by rivet-s 28, is a generally U-shaped frame generally indicated at 2| having a base 22, side walls 23 and aY rear plate 24. There is a pivot 25 supported in the frame side-walls on which is pivotally mounted one end of a member generally indicated at 28, which is one link of a toggle joint. The member 26 has a rearward metallic portion 21 formed as an inverted U, through the side walls of which pass the pivot 25. The member 26 also has a forward metallic portion 28 which is spaced from the portion 2'l'by arsec'tion of dielectric material 29. The forward portion 28 of the link 26 is therefore insulated from the frame 2l.

The forward end of the link portion 28 is formed downwardly as indicated at 30 and is provided with notches 3| at its sides, as indicated in Fig. 8. The switch blade I2,is also provided f with similar notches 3m near its upper end just

notches

33 and 34 at its ends.

below contact I9, as indicated in Fig. 7. The second member or link of the toggle joint is indicated at 32 and is shown'in detail in Fig. 6. The link 32 comprises a flat plate having wide shallow The notches 33 and 34v are sufficiently wide to permit freely spanning of the switch blade I 2 and the forward portion 30 of the link 26 at the base. of the notches 3l and 3Ia respectively. When the toggle link 32 is inserted between the blade I2 and the portion 30 of toggle link 26, it is retained against movement laterally or axially relative to the blade I2 or link portion 30 due to the interlocking notches 3|, 3Ia and 33, 34. The dimensional relations of the notches and the link 32 are such however to permit free rotation between the link 32 land the blade I2 and link 32and-the portion 30. .The

link 32 is held in engagement longitudinally by pressure of the resilient switch blade I2.

There is an upper stop 35 and a lower stop 36 formed as integral parts of the frame side walls 23 which extend, one above, and the other below the toggle member 26 at the point of its insulating portion 29. The rotation of link 23 is therebylimited. In its lowermost position the link 26 rests on the lower stop 36 as indicated in Fig. 2 and the short link 32 assumes the position substantially as shown in this view. link 26 is rotated clockwise about its pivot 25 to the position shown in Fig. 3 wherein any further clockwise rotation is arrested by stop 35, the

rtoggle links

26 and 32 approach alignment and the resulting linear motion is imparted to the switch blade I2 substantially in line with the direction of movement of contact I9.

There is a multiplying arm 31 having va pair of tongues 38 which engage a pair of notches 39 in the upper end of the rear frame member `2I thereby pivotally mounting one end of the arm 31 therein. Supported in the vertical walls of the inverted U-shaped section 21 of the link 26, `is a round bar 4I] adapted to be engaged by the other end of the multiplying arm 31. The arm Y31 may be provided with a rounded 'protuberance 6I on its under surface in order to provide point contact with any suitable switch actuating member such as a rod 42 shown in part in dotted lines, and .the base IB may have an opening as -at 43 to admit the rod 42.

In openatz'on blade l2 and the angularity of the links 2'6 and 32 relative `to each other. This degree of resistance causes some vflexing of the multiplying arm 31. Energy is thereby stored. It will be understood that either or both the link 26 and arm 31 may be constructed so as to ilex sufl'iciently under switch actuating pressure to store up suicien't energy to provide a suitable subsequent snap action. In the illustrated embodiment however, the multiplying arm 31 is preferably constructed so as to flex sufficiently for this purpose, while the link 26 is constructed so as not to iiex any appreciable amount.

As the initial resistance is overcome by the actuating force land 'the arm 31 and

links

26 and 32 are rotated toward the position .shown kin Fig. 3, the developed linear motion due to the relative rotation of

toggle links

26 and 32 will move the switch blade I2 and contact I3 toward vthe left or closed position. Also, as the links 26 and `32 are rotated Iandapproach alignment, the rate of yieldably resisted linear motion developed by further rotation decreases rapidly and the energy stored in the flexed arm 31 is released to provide a snap action. Itwill be seen that as the toggle links 26 and 32 approach Aalign- :tween fthese ,points is negligible and the strut :formed by the substantially aligned toggle links When the 4 is for all practical considerations acting between the iixed pivot 25 and the contact I3. This arrangement prevents the contact I9 from bouncing back as it rapidly engages the contact I8 due to the snap action.

It will be understood that the switch blade II while having some resiliency is sufcientiy rigid to obviate any bouncing away from the contact I9 when rapidly contacted thereby. It 'will also be understood that the toggle links 26 and 32 are stopped just short of alignment or dead center by the lupper stop 35 so as to permit the self return of the mechanism under the urging of the resilient blade I2.

The foregoing description is intended to be illustrative Vand not limiting, the scope of the invention being set forth in the appended claims.

I claim:

1. In a device of the class described, a pair of spaced parallel switch 'blades liked at one end and having attached at their free ends .a pair of normally spaced cooperating contact elements, both'of said blades being resilient but one of said blades being substantially more flexible than the other, a pair 'of toggle links pivotally connected at their inner ends, one of said links having a pivotal connection at its outer end with said more flexible blade, the other of said links being pivoted at its outer end on a iixed pivot, said toggle links being so arranged with respect to said blade that a line through the centersI of their outer pivots is substantially perpendicular to said bladeVand stop means for limiting the rotation of said toggle links in one direction to .a point slightly before dead center.

2. In a device of the class described, a base member, a frame member supported on said base member, a Ypair of spaced parallel switch blades connected yat Vone end -to said base member and carrying at their free ends a pair of normally spaced cooperating contact elements, both of said blades being resilientbut one of said blades being substantially more flexible than .the other, .a pair of toggle links pivotally connected at 'their vinner ends, one of said links having a pivotal connection at its outer end with said more flexible blade at a point on said blade near its -free outer end, the other of said links being pivotally supported in said frame member, said toggle links being so arranged with respect to said blade that a line through the centers of. their outer pivots is substantially perpendicular to said blades, stop means for limiting the rotation of said links in .one direction to a point just short of dead center, and adjustment means for engaging said least flexible blade at a point intermediately of its ends.

3. In a device of the Aclass described, a pair of flexible switch blades lying substantially parallel to each other and inspaced relationship, said switch blades being 4fixed at one end and having attached at their free ends a pair of normally spaced contact elements .having surfaces arranged for abutting engagement, vmeans for adjusting the normal spacing between .said contact elementsA comprising a threaded adjusting element operatively engaging one of said flexible blades at a point intermediately of its length, a

.toggle mechanism comprising a pair of toggle at a point thereon closely adjacent said contact elements, the Lother of .said toggle links being .pivoted at .its outer end on amxed pivot, said attached at their free ends a pair of normally spaced contact elements having surfaces arranged for abutting engagement, means for adjusting the normal spacing of said contact elements comprising a threaded adjusting element operatively engaging one of said flexible blades at a point intermediately of its ends, a toggle mechanism comprising a pair of toggle links pivotally connected at their inner ends, one of said links having a pivotal connection at its outer end with the other of said switch blades at a point thereon closely adjacent said contact elements, the other of said links being pivoted at its outer end on a xed pivot, said toggle links being so arranged with respect to said other blade that a line through the centers of their outer pivot points is substantially perpendicular to said other blade, actuating means for rotating one of said toggle links in a direction toward alignment of said links, a resilient member between said actuating means and said link, and stop means for limiting the rotation of said toggle links in one direction to a point slightly before dead center.

5. In an electric switching device, a resiliently mounted stationary contact element, a movable contact element having a xed path of movement 6 toward and away from said stationary contact element, said contact elements having surfaces arranged for abutting engagement, resilient means for urging said movable contact in a direction away from said fixed contact, a toggle mechanism comprising a pair of links pivotally connected at their inner ends, one of said links being operatively associated at its outer end with said movable contact, the other of said links being pivoted at its outer end on a fixed pivot, said toggle mechanism being arranged so as to cause the movement of said movable contact toward said stationary contact as said toggle links REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 819,322 Struble May 1, 1906 1,689,421 Burnham Oct. 30, 1928 FOREIGN PATENTS l Number Country Date 509,633 Great Britain July 19, 1939