US3522396A

US3522396A - Electrical snap switch

Info

Publication number: US3522396A
Application number: US696452A
Authority: US
Inventors: Alexander R Norden
Original assignee: Slater Electric Inc
Current assignee: Slater Electric Inc
Priority date: 1968-01-08
Filing date: 1968-01-08
Publication date: 1970-07-28
Anticipated expiration: 1987-07-28

Description

July 28, 1970 A-L R. NORDE N suncmxcu. sun SWITCH Filed Jan. 8. 1968 lN-YE NTOR ALEXANDER. R. NORDEN ATTORNEYS United States Patent 3,522,396 ELECTRICAL SNAP SWITCH Alexander R. Norden, New York, N.Y., assignor t0 Slater Electric Inc, Glen Cove, N.Y., a corporation of New York Filed Jan. 8, 1968, Ser. No. 696,452 Int. Cl. Htllh 13/28 U.S. Cl. 200-67 10 Claims ABSTRACT OF THE DISCLOSURE The disclosure herein describes an electrical snap switch of the type generally known as a D.C. switch, in which the contact members are rigid and the usual toggle spring is utilized to provide the contact pressure as well as to provide the toggle action. Additionally, the construction is such that the final make of the circuit is effected on surfaces other than those on which the initial circuit completion occurs, so that arcing which may exist and cause roughening of the surfaces does not roughen the surfaces at which contact is made while the switch is at rest. As will be apparent, the use of rigid contact members makes manufacture of the switch relatively inexpensive and easy, since the rigid parts in addition to being made of less expensive material may be shorter and therefore cost less than the resilient parts which they replace.

In the past, toggle switches of the type here considered were made with resilient fixed contact members and a toggle member which engaged between the contact members to complete the circuit, the over-center spring of the toggle action being compressed between a handle member and the toggle member proper. When switches of this type were utilized, particularly in a situation where the current carried was relatively heavy, there was a tendency for arcing to occur and this resulted in annealing of the springy parts. The annealing of the parts in turn resulted in lowered contact forces and greater contact resistance, which increased the internal heating and often led to burn-out of the switch.

It is therefore an object of this invention to provide a snap or toggle switch of the type commonly known as a D.C. snap switch wherein the fixed contacts are rigid and wherein the spring utilized as the over-center spring of the toggle action also supplies the force to press the contacts against each other and maintain sufiicient contact pressure to assure low resistance at the contacts, preventing undue arcing and heating and increasing the switch life.

It is another object of the invention to produce such a D.C. snap switch at low cost while at the same time providing a structure in which the initial make of the circuit is not on the same portion of the fixed contacts through which the circuit is completed when the movable toggle member is at rest.

Other objects and features of the invention will appear when the following description is considered in connection with the annexed drawing in which:

FIG. 1 is a vertical cross-sectional view of the switch of my invention, the view being taken on the plane of line 11 of FIG. 2;

FIG. 2 is a transverse cross-sectional view of the switch of FIG. 1, the view being taken on the plane of the line 22 of FIG. 1 but showing the switch handle and the toggle member in a central position;

FIG. 3 is a horizontal cross-sectional view taken on the plane of the line 33 of FIG. 1;

FIG. 4 is an enlarged perspective view of one of the fixed contact terminal members; and

FIG. 5 is an enlarged perspective view of one of the 3,522,396 Patented July 28, 1970 terminal members and its integral toggle supporting portion.

Referring now to the drawings, and particularly to FIGS. 1 through 3, it will be seen that the switch of this invention comprises the usual housing 10 having

side walls

13 and 14 and end walls 11 and 12. The open front of the insulating housing 10 is closed by means of the cover plate 15 which has an aperture therein through which the handle 16 extends. Handle or operating member 16 has trunnion portions 17 extending sidewise therefrom, which trunnion portions seat in notches 18 formed 7 in the

side walls

13 and 14, the trunnions being held in position in these notches by means of the cover plate 15.

Pivotally mounted beneath the handle member 16 (as seen in FIGS. 1 and 2) and with the center of its pivotal axis in vertical alignment with the axis of the handle 16, is a toggle member 20, which member is of a generally U-shaped having a projection 21 extending upwardly from the base of the U. Extending between the projection 21 and a boss 22 formed on the handle 16, is a compression spring 23 which serves in the usual manner as an over-center spring and thus provides the snap action which is desirable. Toggle member 20 is pivotally mounted as indicated above by means of the

horizontal extensions

24 and 25. Extension 24 is mounted in a slot in an outwardly offset thickened portion 26 of the wall 14, while extension 25 is mounted in the horizontally extending portion of terminal 30. Toggle member 20 is additionally provided with a contact making extension 27.

Referring now to FIG. 5, terminal 30 comprises a generally rectangular portion 31, the center portion of which is convex outwardly as indicated at 32 and provided with a boss 33 which is threaded and in which a screw 34 (see FIG. 2) is mounted to provide for connection of the switch in an electrical circuit. Extending upwardly from the rectangular portion 31 of the terminal is integral arm 35 having a substantially right angle bend at the top thereof, forming the extension 36 which as clearly shown in FIG. 5, is of V shape, providing a pivotal edge on which the extension 25 of terminal member 20 rests.

Referring now to FIG. 3, it will be seen that the terminal 30 is mounted in the housing 10 by inserting it from the bottom, with the sides of the rectangular portion 31 positioned in the guideways 37 formed in the thickened lower portions 38 of the side wall 13. As clearly indicated in FIG. 2, when so inserted the arm 35 and extension 36 lie within the main portion of the side wall 13 and between two inwardly extending ribs 39 formed integral with the upper portion of that wall (FIGS. 1 and 2). When the terminal 30 is fully in position, a lance portion 40 formed on the bottom edge thereof is bent inwardly as indicated particularly in FIGS. 2 and 3, thus holding the terminal in position. If desirable, the bottom wall 41 of the housing 10 may be slightly sloped adjacent the terminal 30 so that the lance as it is bent inwardly will force the terminal 30 into its predetermined position seating against the upper edges of guideways 37.

Referring now to FIG. 4, there is shown therein one of the fixed contact terminals 42. These terminals are in many ways similar to the terminal 30 already described and comprise the rectangular portion 43 having an outwardly convex portion 44, with an inwardly extending boss 45 which is threaded to receive a screw for fixing an external conductor to the terminal. An inwardly extending arm 46 protrudes from the side of the terminal and is bent off through a notch in the rectangular rim portion 43. This rim portion is also provided with cuts forming the

lances

47 and 48, which as will appear, perform in the same manner as the lance 40 to hold the terminal and contact arm in position. The lower portion of each side wall of the housing 10 is cut out to form an opening 50 (see FIGS. 1 and 3) and the lower portions of the side walls 11 and 12 are provided with the grooves or guideways 51 into which the sides of the rim portion 43 are inserted from the bottom. It will be noticed that a slot 52 is also formed in each side wall 11 and 12 and an opening corresponding to the curved shape of the contact arm 44 is also formed in the bottom wall.

When the terminal 42 and associated contact arm 46 have been placed in position so that the upper edge of the terminal seats against the lower edge of the opening, the

lance

47 or 48, as the case may be, is bent inwardly to hold the terminal in position.

Referring now to FIGS. 1 through 3, it will be seen that the spring 23- constantly urges the toggle downwardly, causing the

extensions

24 and 25 to rest in their respective seats, as shown in FIG. 2 wherein the toggle is shown in its instantaneous center position. As the toggle member is operated to one of its extreme positions such as that shown in FIG. 1, the downward extension 27 engages a contact arm 46 and moves therealong under drive of the spring 23. As the extension 27 rides along the arm 46 the toggle is caused to incline slightly so that it rests almost entirely upon extension 36 of arm 35, rising slightly from the opposite seat. It will be appreciated that a component of force of the toggle spring 23 acts to press the extension 27 against the contact arm.

Further, since the spring 23 is made of heat-treated spring steel and since it is removed from any area in which arcing can occur, there is no annealing of this spring, and the contact pressures remain constant, greatly lengthening the life of the switch.

In the past, resilience was usually provided through the use of longer copper or brass terminal members, provided with a U bend. The result was that during use and consequent arcing, even of a minor character, the pieces became heated and annealed, the resilience decreased, contact pressure thereupon decreased, arcing became greater and a cycle of destruction was produced.

By the present construction the pressure at the current carrying pivot terminal comprising extension 36 of arm is increased to a high value at the moment of lift-ofi of the opposite extension 24 from its seat and remains at a high though slightly decreased value as the spring 23 expands and the toggle member completes its movement.

Additionally, by the present construction a dual wiping action is produced. Due to the extent of the wiping arm 46 the contact is first made at the outer end thereof and thus any arcing which may occur is not apt to afiect the area at which the extension 27 is positioned at rest. Also, due to the tilting action described above the point of con tact of extension rises along the side of that extension as the toggle approaches its rest position so that the contact arm 46 wipes the extension. This action thus assures that the making surfaces of both the extension 27 and the contact arm 46 are clean.

In operation it is of course only necessary to move the operating handle 16 from a position such as that shown in FIG. 1 to one in which the handle has been rotated through substantially 90 degrees to cause the switch toggle member to disengage from one of the contact arms 46 and engage with the other contact arm 46, or in the case of a single-pole switch, to assume a circuit open position.

As is customary with switches of the toggle or overcenter type, the handle does not directly operate the toggle member but rather merely moves the upper end of the spring 23 over-center, thereby causing the toggle member to move with a rapid action from the position shown in FIG. 1, for example, to the position in which the toggle member has rotated in a clockwise direction about its axis to its other rest position. It will be noted that the rest position of the handle is determined by contact of the raised surfaces 19 on the handle 16 with the underside of the strap 15.

While a preferred embodiment of the invention has been described, it will of course be understood that many variations thereof are possible within the scope of my invention.

What is claimed:

1. An electrical switch of the snap acting toggle type comprising, in combination, a generally U-shaped toggle member of electrically conductive material, means pivotally mounting said toggle member for rotation about an axis extending through the ends of the arms of the U, said pivotal mounting comprising electrically conductive material, an operating handle pivotally mounted on an axis parallel to said toggle member axis in a common plane, said operating handle extending away from said toggle member and having a projection thereon extending toward said toggle member, a spring extending between said projection and said toggle member to cause said toggle member to rotate under drive of said spring when said operating handle is activated through an are such that said projection passes through said common plane, at least one fixed rigid contact mounted in position to be engaged by said toggle member as it approaches one of its limit positions, said contact member being formed and positioned to tilt said toggle member laterally against the force of said spring, and means for connecting said contact and said pivotal mounting for said toggle member in an electrical circuit, said toggle member having a portion extending away from its pivotal mounting, said fixed contact engaging the side of said portion as the toggle member approaches one of its limit positions to thereby tilt said member laterally against a component of force supplied by said spring, said spring force thus serving to supply contact pressure.

2. An electrical switch as claimed in claim 1 wherein tWo fixed rigid contacts are provided one adjacent each limit position of said toggle member.

3. An electrical switch as claimed in claim 1 wherein said toggle member, operating handle and fixed contact are mounted in an electrically insulating housing, said fixed contact and toggle member conductive pivotal mounting being individually connected to terminals accessible from the exterior of said housing.

4. An electrical switch as claimed in claim 3 wherein said toggle member mounting comprises lateral extensions on the arms of said U, one of said extensions resting in a notch in a wall of said housing and the other extension resting on said electrically conductive pivotal mounting.

5. An electrical switch as claimed in claim 3 wherein said electrically conductive pivotal mounting is integral with one of said terminals and wherein said fixed contact is integral with the other of said terminals.

6. An electrical switch of the snap acting toggle type comprising, in combination, a generally U-shaped toggle member of electrically conductive material, means pivotally mounting said toggle member for rotation about an axis extending through the ends of the arms of the U, said pivotal mounting comprising electrically conductive material, an operating handle pivotally mounted on an axis parallel to said toggle member axis in a common plane, said operating handle extending away from said toggle member and having a projection thereon extending toward said toggle member, a spring extending between said projection and said toggle member to cause said toggle member to rotate under drive of said spring when said operating handle is activated through an are such that said projection passes through said common plane, at least one fixed rigid contact mounted in position to be engaged by said toggle member as it approaches one of its limit positions, said contact member being formed and positioned to tilt said toggle member laterally against the force of said spring, and means for connecting said contact and said pivotal mounting for said toggle member in an electrical circuit, said fixed contact being inclined across the path of travel of said toggle member whereby said fixed contact limits the movement of said toggle memher and said toggle member first engages said contact and then slides over the contact to the limit position.

7. An electrical switch as claimed in claim 6 wherein two fixed rigid contacts are provided one adjacent each limit position of said toggle member.

8. An electrical switch as claimed in claim 6 wherein said toggle member, operating handle and fixed contact are mounted in an electrically insulating housing, said fixed contact and toggle member conductive pivotal mounting being individually connected to terminals accessible from the exterior of said housing.

9. An electrical switch as claimed in claim 8 wherein said toggle member mounting comprises lateral extensions on the arms of said U, one of said extensions resting in References Cited UNITED STATES PATENTS 1,783,298 12/1930 Meuer. 2,011,293 8/1935 Krieger. 2,688,057 8/1954 Slater. 2,899,513 8/ 1959 Schmidt.

ROBERT K. SCHAEFER, Primary Examiner a notch in a wall of said housing and the other extension 15 D. SMITH, 111., Assistant Examiner resting on said electrically conductive pivotal mounting.