US3319021A

US3319021A - Electric switch

Info

Publication number: US3319021A
Application number: US539902A
Authority: US
Inventors: Arthur L Good
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1966-04-04
Filing date: 1966-04-04
Publication date: 1967-05-09
Anticipated expiration: 1984-05-09

Description

May 9, 1967 A. L. GOOD ELECTRIC SWITCH Filed April 4, 1966 FIG. I

Q l imm m m a W x9 2 a y F W 6 r 5 w m m INVENTOR ARTHUR L. GOOD ATTORNEY United States Patent 3,319,021 ELECTRIC SWITCH Arthur L. Good, Elkhart, Ind., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Apr. 4, 1966, Ser. No. 539,902 8 Claims. (Cl. 200-67) This invention relates to electric switching devices, and more particularly, to a double pole, single throw switch.

An object of the present invention is to construct a reliable, rugged switch for carrying electrical loads with a minimum of trouble during a long service life.

Another object of the present invention is to provide a compact switch assembly wherein a plurality of switch blades are responsive to a common'operating lever.

The present invention has another object in that the. force applied to one switch blade of an electric switch is transmitted to the second switch blade thereof with reducing contact pressure.

. It is another object of this invention to construct one switch blade of an electric switch from a single strip of material into mounting and operating portions so that force applied to a second switch blade is transmitted to such operating portion.

This invention has another object in that the mounting and operating portions of a switch blade are integrally formed and connected by a flexible hinge.

A further object of the present invention is to provide one switch blade of an electric switch with bowed surfaces that are engaged by force transmitting means movable as a unit with a second switch blade.

The present invention has still another object in the construction of a simple switch assembly including a first arm secured at one end to the housing and a contact disposed on the arm, and a second arm disposed within the housing in proximity to the first arm and a contact disposed on the second arm and cooperating means on the first and second arms to transmit forces therebetween during a switching operation.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a vertical cross-sectional view of a switch embodying the present invention with its contacts in open position;

FIG. 2 is a view similar to FIG. 1, but showing the contacts in closed position;

FIG. 3 is an exploded perspective view of a detail of FIG. 1; and

FIG. 4 is a top plan view of FIG. 1 on a reduced scale with parts broken away.

As is illustrated in FIGS. 1 and 4, the present invention is embodied in a switch housing, indicated generally at 10, made of any suitable dielectric material and having a substantially rectangular configuration formed by a pair of

end walls

12 and 14 joined to a pair of

side walls

16 and 18. A barrier 20 extending from end wall 12 terminates in spaced relation to the opposite end wall 14 and is centrally disposed between the

side walls

16 and 18 to divide the housing into spaced contact compartments joined by an end compartment. One end of the barrier 20 defines a mounting ledge and the opposite end is stepped downwardly with a hemispherical stop member 22 on its end portion.

A switch operating lever, indicated generally at 24, is formed from an elongated strip of spring material having an end secured to the mounting ledge on barrier '20 as by screws 26. Intermediate its ends, the lever strip 24 has a generally U-shaped cutout defining an operating tongue 28, the free end of which is disposed above the stop 22 and is normally biased upwardly as viewed in FIG. 1. The left end of lever strip 24 carries a pair of L-

shaped lugs

30 and 130, one on each edge with their free ends extending under

stop elements

32 and 132, respectively, formed on the inside of housing wall 14. An L-shaped arm 34 also depends from the end of lever strip 24 with its free end extending in a direction opposite to the lugs 30 and the arm 34- is centrally disposed between the

lugs

30 and 130 and its free end defines a knife edge engaging a V-shaped notch 36 centrally located on a side of a generally rectangular toggle link 38. The toggle link 38 is made of any suitable dielectric rigid material and, as is shown in FIG. 4, has end projections 40 and extending from the side opposite the notch 36; the

projections

40 and 140 have V-shaped notches 42 and 142, respectively.

The toggle link 38 with its

end projections

40 and 140 define a U-shaped configuration so that it is disposed in the housing end compartment and the

projections

40 and 140 extend into the two contact compartments, respectively, for operative connection to the contact carrying assemblies. Since the two contact carrying assemblies are identical in structure, only one assembly is being described in detail, while the other assembly is merely being identified on the drawing by reference numerals having 100 added to the numerals identifying identical structure of such one assembly. For example, a lost motion leaf 44 has a knife edge 46 engaging the notch 42 and it is to be understood that the other lost motion leaf 144 has a knife edge 146 engaging the notch 142.

As is illustrated in FIG. 3, the lost motion leaf 44 comprises a generally rectangular strip of flexible sheet material having flanges 48 along a portion of each side edge to add rigidity to the strip. On the end opposite to knife edge 46, the leaf is bent downwardly to form an offsetting wall 49 and terminates in tab 50 which is offset from the plane of the leaf 44. Intermediate its ends, the leaf 44 has a keyhole slot 52 defining a loose fitting connecting means for a contact carrying blade 54. The blade 54 is an elongated flexible strip of electric conductive material of generally rectangular configuration having an I-shaped perpendicular flange 56 on one end. The blade 54 has a circular aperture 58 adjacent the end flange 56, a square aperture 60 intermediate its ends and a circular aperture 62 adjacent its opposite end. A contact 64 is secured to the blade 54 between the square aperture 60 and the circular aperture 62. The circular aperture 62 defines a mounting aperture for the end of the blade 54 which is thus secured to an internal ledge of the housing 10 by any suitable means, such as a nut and bolt fastener 65.

The leaf 44 is assembled on the blade 54 by placing the flange 56 in the keyhole slot 52 and sliding the leaf 44 in a direction toward the mounting aperture 62 with the slots of flange 56 receiving the edges of the narrow part of the keyhole slot 52; during such sliding movement, the tab 50 will fall into the square aperture 60 and the abutment of the edge of aperture by the offsetting wall 49 of tab 50 limits the sliding movement. The bottom edge of the offsetting wall 49 rests on the top surface of the blade 54 so that the leaf 44 is superimposed above the blade 54 in a plane defined by the slots of the flange 56. A force transmitting member in the form of an annular disc 66, made of any suitable insulating material such as rubber, has a centrally located mounting stud 67 on its top surface, which is received in the aperture 58 of the blade 54. As is illustrated in FIG. 2, the undersurface of disc 66 has an annular cutout which has a larger depth adjacent the periphery of the disc 66 and a decreasing smaller depth toward the center; the annular cutout thus provides the undersurface of disc 66 with a peripheral annular bearing surface 68 and a central hemispherical bearing surface 69. The stud 67 is 3 integrally secured to the blade 54 as by pressing fitting or snap fitting so that the disc 66 moves as a unit with the blade 54. In its assembled relationship, the upper end of stud 67 is disposed under the enlarged portion of the keyhole slot 52 and thus does not interfere with movement of the leaf 44.

A second contact carrying blade 70, which is stamped from a single flexible strip of electric conductive material, includes a generally U-shapedtop plate 71 having a tongue on one end, to which a contact 72 is secured for cooperation with the contact 64. The blade top 71 has a central cut-out of rectangular configuration defining a center leg 74 disposed between a pair of

side legs

76 and 78. As is shown in FIG. 3, the

side legs

76 and 78 are joined at one end to define the U-shaped configuration of the top plate 71; intermediate their ends, the legs 76 and 7 8 are bowed upwardly to form

arcuate ridges

77 and 79, respectively. The force transmitting disc 66 is superimposed over the

arcuate ridges

77 and 79 and is adapted to bear against the same for switching actuation as will be described hereinafter. The end of blade 70, opposite to the contact end 72, has a depending L-shaped flange 80 being integrally formed with the center leg 74 and the

side legs

76 and 78. The bottom plate or center leg 74 is a mounting plate and extends perpendicularly from the flange 80 from an edge below the plane defining the

side legs

76 and 78; thus, the center leg 74 is disposed in-a plane below the plane of

legs

76 and 78. The end of center leg 74 has a mounting aperture which receives a fastening device such as a rivet 75 for securing the blade 70 to an internal ledge of the housing 10. With the above arrangement, the junctures between

side legs

76 and 78 and the flange 80 define resilient hinges 82 and 84, respectively, whereby the top plate 71 is movable relative to the bottom plate 74.

In the following description of operation of the above device, it will be assumed that the switch is connected between a power source and a device being controlled; accordingly,

rivets

75 and 175 are terminals connected to power lines L and L (not shown), respectively, and

fasteners

65 and 165 are terminals connected to leads T and T (not shown), respectively, of the controlled device. PIG. 1 represents the normally open condition of the switch 10 wherein contacts 64 and 164 are separated from

contacts

72 and 172, respectively, so that both sides of the power lines L and L are broken.

In response to a force applied to plunger P, the lever tongue 28 is depressed and as it moves through the cutout portion of the lever 24, the

lever lugs

30 and 130 are moved away from the

housing stops

32 and 132, re-

The simultaneous movement of lever arm 34 spectively.

link 38 to pivot about the knife edge 46 causes the toggle until the instant of snap over, which occurs when the through dead center and The toggle link 38 with V-shaped notch 36 is moved past the V-shaped notch 42.

its V-

shaped notches

36 and 42 receiving the

knife edges

34 and 46, respectively, constitutes a snap acting device that causes movement of the leaf 44 (144-) with a snap action. As viewed in FIG. 1, the snap acting device exerts a downward force on the leaf 44 (144) until snap over occurs whereupon the leaf is actuated with an up ward force. During such snap over the narrow edges of keyhole slot 52 (152) transfer from the bottom to the top edges of the slot in the flange 56 (156).

The upward force on leaf 44 (144) causes an upward movement of the blade 54 (154) whereby the annular surface 68 (168) of the force transmitting disc 66 (166) is displaced from the ridges 77 and 79 ('177 and 179) which thus assume their normally bowed condition. Release of the stress on the bowed ridges 77 and 79 (177 and 179) permits the entire top plate 7 1 (171) to flex upwardly about the flexible hinges 82 and 84 (182 and 184), whereupon the inherent resiliency of the blade plate 71 (I171) biases its contact 72 (172) into engagement with the contact 64 (164). The switch will remain in the closed contact position of FIG. 2 as long as the plunger P is depressed.

Upon release of the actuating force on the plunger P,

The downward force on the leaf 44 (1'44) and on the blade 54 (154) is transmitted by the disc 66 (1166) to the bowed ridges 77 and 79 (:177 and 179); accordingly,

the ridges are stressed causing the blade plate 71 (17 1) to flex downwardly about the flexible hinges 82 and 84 (1'82 and 184) whereupon the contact 72 (172) is separated from the contact 64 (164) and the switch is returned to its normal open position. The amount of stress applied to the bowed ridges 77 and 79 (17 7 and 179) is limited by the engagement of the discs hemi spherical surface 69 (169) with the top of the fastening rivet 75 which defines stop means for the disc 66 Inasmuch as the present invention is subject to many variations, modifications and changes in details, it is intended that all matter contained in the above description or shown on the accompanying drawing, shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an electric switch, the combination comprising a switch housing,

first contact carrying switch blade means having an operating portion and a mounting portion secured to said housing,

I second contact carrying switch blade means movably mounted in said housing and cooperating with said first blade means to define switch open and closed positions,

flexible hinge means between said operating portion and said mounting portion biasing said operating portion toward said second blade means whereby said operating portion is normally biased to a switch closed position,

force transmitting means on said second blade means engaging the operating portion of said first blade means for moving the same to a switch open position, and force applying means including a leaf member having spaced parts operatively connected to said second blade means one of said parts defining a lost motion connection with said second blade means causing said force transmitting means to move relative to the operating portion of said first blade means, and

actuating means acting on said leaf member to reverse the action of said second blade means whereby said first and second blade means are movable during a switching operation.

2. The invention as recited in claim 1 wherein said operating portion includes ridge means bowed toward said force transmitting means.

3. The invention as recited in claim 2 wherein said force transmitting means comprises disc means having an annular undersurface engaging said ridge means.

4. The invention as recited in claim 3 wherein the operating portion of said first blade means includes a pair of side legs and the mounting portion of said first blade means includes a central mounting leg, and wherein said disc means has a central hemispherical surface disposed for movement between said pair of side legs and relative to said central mounting leg.

5. In an electric switch, the combination comprising a switch housing,

first contact carrying switch blade means including a pair of side legs, a central mounting leg having a portion secure-d to said housing, and flexible hinge means defining between said side legs and said mounting leg, said pair of side legs having bowed ridge means defining operating portions, second contact carrying switch blade means in said housing cooperable with said first blade means to define switch open and closed positions, force transmitting disc means on said second blade means having an annular undersurface engaging said ridge means and having a central hemispherical surface disposed for movement between said pair of side legs, force applying means acting on said second blade means whereby said force transmitting disc means acts against said ridge means and normally biases first blade means to a switch open position, actuating means operative to reverse the action of said second blade means whereby said first and second blade means are movable during a switching operation, and stop means rigidly mounting said central mounting leg to said housing and being engaged by said hemispherical surface to limit bowing of said ridge means. 6. The invention as recited in claim 5 wherein said housing includes a pair of switching compartments connected by an end compartment, said first and second blade means comprises a pair of identical first and sec ond blades with one pair mounted in each switching compartment, and wherein said actuating means includes an operating lever and snap acting means operatively connected between said lever and the force applying means for each of said second blades.

'7. The invention as recited in claim 6 wherein said lever has a fixed portion mounted on said housing and an integrally formed operating tongue bent upwardly from said fixed portion.

8. The invention as recited in claim 7 wherein said housing has a stop element engageable by said operating tongue to limit the actuating force on said lever, and wherein said lever and said housing have cooperating stop means to limit return movement of said lever when the actuating force is released.

References Cited by the Examiner UNITED STATES PATENTS 2,751,450 6/1956 Smith 20067 ROBERT K. SCHAEF ER, Primary Examiner. D. SMITH, JR., Assistant Examiner.

Claims

1. IN AN ELECTRIC SWITCH, THE COMBINATION COMPRISING A SWITCH HOUSING, FIRST CONTACT CARRYING SWITCH BLADE MEANS HAVING AN OPERATING PORTION AND A MOUNTING PORTION SECURED TO SAID HOUSING, SECOND CONTACT CARRYING SWITCH BLADE MEANS MOVABLY MOUNTED IN SAID HOUSING AND COOPERATING WITH SAID FIRST BLADE MEANS TO DEFINE SWITCH OPEN AND CLOSED POSITIONS, FLEXIBLE HINGE MEANS BETWEEN SAID OPERATING PORTION AND SAID MOUNTING PORTION BIASING SAID OPERATING PORTION TOWARD SAID SECOND BLADE MEANS WHEREBY SAID OPERATING PORTION IS NORMALLY BIASED TO A SWITCH CLOSED POSITION, FORCE TRANSMITTING MEANS ON SAID SECOND BLADE MEANS ENGAGING THE OPERATING PORTION OF SAID FIRST BLADE MEANS FOR MOVING THE SAME TO A SWITCH OPEN POSITION, AND