US3585325A - A snap-action switch including a leaf spring strip reformable into two predetermined positions - Google Patents

Abstract

There is provided a novel type of switch comprising essentially one or more tempered, deformable leaf springs rigidly attached at each end thereof to a rigid bar wherein the length of the spring is greater than the length of the bar whereby there is formed a bow in the spring. When a clamping force is applied to the bowed spring, the deformation caused thereby produces marked bowing in one portion of the spring and substantial flattening in the remaining portion. When the clamping force is reversed and applied to the bowed section, a snap-action occurs causing the previously bowed section to flatten and the previously flattened portion to bow. This reversal of deformation is very rapid and can thus be utilized as the on/off mechanism of a switch. This principle is utilized in the two principal modifications of the invention. In one modification the clamping action is applied in the form of a slide and in the other in a toggle switch.

Description

United States Patent [72] Inventor Alfred W. Stewart 107 Boulevard, Mountain Lakes, NJ. 07046 [21 Appl. No. 800,987 [22] Filed Feb. 20, I969 [45] Patented June 15, 1971 [54] A SNAP-ACTION SWITCH INCLUDING A LEAF SPRING STRIP REFORMABLE INTO TWO PREDETERMINED POSITIONS 6 Claims, 9 Drawing Figs.

[52] U.S. Cl 200/67, 74/100 [51] Int. Cl ..II01h 13/48 [50] Field of Search 200/67, 67 D1, D2; 74/100 P [56] References Cited UNITED STATES PATENTS 2,755,352 7/1956 Birkemier ..200/67 D2 (UX) 1,973,800 9/1934 Curtis ..200/67 D2 (UX) 3,050,599 8/1962 Brevick ...200/67 D2 (UX) 3,109,901 11/1963 Strauss ..200/67 D2 (UX) I i 13,5s5,325

3,277,257 10/1966 Doktor ..200/67 D2 (UX) FOREIGN PATENTS 1,332,793 6/1963 France ..200/67 D2 (UX) Primary ExaminerDavid Smith, Jr. Attorneys-Lerner and Behr ABSTRACT: There is provided a novel type of switch comprising essentially one or more tempered, deformable leaf springs rigidly attached at each end thereof to a rigid bar wherein the length of the spring is greater than the length of the bar whereby there is formed a bow in the spring. When a clamping force is applied to the bowed spring, the deformation caused thereby produces marked bowing in one portion of the spring and substantial flattening in the remaining portion. When the clamping force is reversed and applied to the bowed section, a snap-action occurs causing the previously bowed section to flatten and the previously flattened portion to bow. This reversal of deformation is very rapid and can thus be utilized as the on/off mechanism of a switch. This principle is utilized in the two principal modifications of the invention. In one modification the clamping action is applied in the form of a slide and in the other in a toggle switch.

PATENTEU JUN 1 519m 3, 585, 325

INVEN'TOR. ALFRED W. STEWART LERNER a BEHR ATTORNEYS A SNAP-ACTION SWITCH INCLUDING A LEAF SPRING STRIP REFORMABLE INTO TWO PREDETERMINED POSITIONS FIELD OF THE INVENTION Novel spring activated switching mechanisms.

DESCRIPTION OF THE PRIOR ART It is known in the switching art to apply the snap-action of a deformed spring to make and break electrical contacts. Most of these switches known in the art require rather bulky and complex activating mechanisms in order to utilize the snap-action of the bowed spring. Furthermore, it should be noted that all of the snap-action spring switches known to the prior art depend for their action on the complete reversal of the direction of curvature of the entire leaf spring. That is to say, a convex surface of the spring is converted into a concave surface along the entire length of the spring. It is clear that such a mechanism requires a greater space and greater force for operation than one which is operative without the necessity of entire reversal of the direction of deformation.

Among the snap-action switches known to the prior art may be included those disclosed in U.S. Pat. No. 2,592,357 to Trainor; in U.S. Pat. No. 2,618,715 to Cataldo; in U.S. Pat. No. 2,916,575 to Mais; in U.S. Pat. No. 2,794,890 to Taylor; in U.S. Pat. No. 3,109,901 to Strauss; and in U.S. Pat. No. 2,391,238 to Hormann.

SUMMARY OF THE INVENTION In the switching mechanism of the present invention a leaf spring is rigidly affixed to a rigid bar in such a'manner that the leaf spring presents a concave face to the bar to which it isattached. It is within the contemplation of the present invention that more than one leaf spring may be attached to any one bar. A deforming force is then applied to the bowed leaf spring at a point substantially closer to one point of attachment of the spring than to the other. The effect of this deforming force is to cause an increase in the degree of curvature of the longer part of the leaf and a substantial flattening of the remaining, shorter, portion of the spring causing said shorter portion to lie close to and substantially parallel to the bar. When the deforming force is moved along the spring past the midpoint thereof, a snap-action occurs, wherein the previously curved portion becomes substantially flat and the previously flat portion becomes considerably bowed. This interesting snap-action property of bowed leaf springs which has been discovered herein may be utilized to make and break electrical contacts which are placed on and adjacent to the spring leaf and the rod or bar. Examples of such switches are illustrated in detail hereinbelow.

In one modification of the invention the deforming force is applied by a slide which applies its force in the central segment of the leaf spring. By moving said slide towards one of the other ends of the leaf spring, the substantially bowed section of said spring is caused to snap and consequently travel (like a travelling wave) from one end of said spring to the other, thereby making or breaking electrical contacts. Depending upon the design of the individual switch, it is within the scope of the present invention that the slide may be of insulating or conducting material.

In another principal modification of the present invention, the bar bearing the bowed leaf spring thereon is placed in a tube having an internal cross section less than the maximum distance between the upper surface of the bowed leaf spring and the bottom opposite surface of the rigid rod or bar. It is preferred in this modification, however, to utilize a rod bearing a leaf spring on both sides thereof in which case it is placed in a tube having a cross section less than the distance between the top of the upper bowed leaf to the bottom of the lower bowed leaf. The combination is then inserted into the tube so that the rod lies approximately on a diagonal drawn from the upper front end of the tube to the lower rear end of the tube. When the rod is rotated in'the plane in which it lies so that the front end of the rod is now at the bottom front end of the tube and the rear of the rod is at the top rear end of the tube, the bowed spring leaves reverse their location of maximum bowing thus giving rise to a switching action.

It is an object of the present invention to provide a contact mechanism or quick action switch.

It is a further object of this invention to provide a quick action switch with a plurality of contacts which will assure a proper and simultaneous establishment or interruption of all contacts or circuits governed thereby.

It is yet another object of the present invention to provide a switch of a type referred to hereinabove of such structure and arrangement as to provide a snap-action switch which may be operated by a slow moving actuator having a relatively short path of travel. Said actuator being capable of effecting instability and sudden shifting of the switch before it reaches neutral dead center position in which contact engagement is at lowest pressure.

DESCRIPTION OF THE DRAWINGS All drawings illustrate a cross section viewed perpendicularly to the plane of the leaf spring and perpendicular to the lengthwise axis of the rod or bar to which it is attached.

FIG. 1 shows a bar having attached to the upper side thereof a bowed leaf spring.

FIG. 2 illustrates the leaf spring of FIG. I wherein the said leaf spring is compressed by a slide bar.

FIG. 3 shows the compressed leaf spring of FIG. 2 illustrating one manner of attaching electrical leads and contacts to the device.

FIG. 4 shows a bar having spring leaves attached to the upper and lower end thereof.

FIG. 5 illustrates the system of FIG. 4 having attached thereto electrical leads and contacts as well as slide bars compressing the upper and lower leaves.

FIG. 6 shows the device of FIG. 5 with the slide bar moved across the center point of the device and illustrating the overcenter snap-action thereof.

FIG. 7 illustrates the use of a device of FIG. 4 having electrical leads and contacts attached thereto in the tube-toggle modification of the invention.

- FIG. 8 illustrates the device of FIG. 7 in the alternately switched position.

FIG. 9 illustrates an end view of the device FIG. 7 taken along the arrows 9-9 thereof.

- DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention illustrates a novel method of overcenter snap-action switching and devices for carrying out such switching. The figures discussed hereinbelow illustrate a number of modes in which this over center snap action can be utilized in on/off switching. It should be stressed however, that the combination and permutations of switching illustrated by the figures hereof merely show certain possible combinations; other combinations will be. clear to one skilled in the art and are to be considered as included within the scope of the 1 present invention.

The basis of the device as shown in FIGS. 1 and 2 is a rigid bar 10 constructed of electrically conductive or nonconductive material. There is rigidly attached to bar 10 as by fixing means 12 and 13, a bowed leaf spring 11 which may similarly be of electrically conducting or electrically nonconducting material. The choice of whether the constructing materials are electrically conducting or nonconducting will depend solely upon the desired circuitry of the switch constructed in accordance with the present invention. It has been found however, that it is preferable to manufacture the bar 10 out of nonconducting material and the leaf spring 11 out of a tempered metal to provide the desired mechanical properties of the device.

The leaf spring 11 is compressed by slide 22 which is preferably nonconducting so as to be independent of the electrical circuitry of the switch.

FIG. 3 illustrates one simple modification of the device. Electrical contacts 41 and 43 are attached to the leaf spring 11 and electrically connected to insulated lead wires 31 and 33. (If desired electrical contacts 41 and 43 may be fitted into leaf spring 11 in such a manner as to be electrically insulated therefrom). In a similar manner electrical contacts 42 and 44 are set into bar and electrically connected to insulated electrical leads 32 and 34 respectively. Where bar 10 is constructed of an electrically nonconductive material it is not necessary to insulate contacts 42.and 44 from bar 10.

As illustrated in FIG. 3, and assuming a modification where contacts 41 and 43 are electrically insulated from leaf 11, the device is shown in a position giving rise to electrical contact at contacts 43 and 44 between insulated leads 33 and 34 respectively and noncontact with respect to contacts 41, 42. If slide 22 is moved towards fixing means 13, (to the position illustrated in FIG. 2) an overcenter snap-action will occur giving rise to electrical contact between contacts 41 and 42 and breaking the contact between contacts 43 and 44. Of course, if desired a single pole switch is possible with the use of only one set of contacts 41, 42 or 43, 44.

The FIG. 4 shows a basic device similar to that illustrated in FIG. 1 but having an additional leaf 16 connected to bar 10 by fixing means 14 and 15.

An Embodiment of the device of FIG. 4 is shown in FIG. 5. In this modification leads 31 and 33 are connected to contacts 41 and 43 in the same manner illustrated in FIG. 3 and contacts 42 and 44 are similarly located on bar 10, but are electrically connected with electrically insulated leads 52 and 54 respectively which are passed through channels in bar 10. Additionally into device provided with contacts 47, 48 and 49, 46 and appropriate leads 57, 58 and 59, 56 respectively. Slides 22 and 23 are placed in the position shown giving rise to electrical contact between point 43 on a first curved portion of leaf 11 and point 44; and point 46 on a fifth curved portion ofleaf 16 and point 49; and noncontact with respect to point 41 on a second curved portion of leaf 11 and point 42; and point 47 on a sixth curved portion of leaf 16 and point 48.

When slides 22 and 23 are moved towards fixing means 13 and away from fixing means 12 and 14 to a second position, electrical contact is broken between contact 43 on a fourth curved portion of leaf 11 and point 44; and contact 46 on an eighth curved portion of leaf 11 and point 46 and electrical contact made between contact 41 on a third curved portion of leaf l1 and point 42; and contact 47 on a seventh curved portion of leaf l6 ani point 48. It is to be understood that slide bars 22 and 23 may operate independently if desired.

Turning to FIGS. 7 and 8 there is illustrated the toggle modification of the present invention. The basic unit of the modification is the arrangement of FIG. 4 having attached thereto a handle 79.

The device further comprises a housing 90 of desired external cross section (in the modification illustrated herein, the cross section of the housing is circular) provided with electrical contacts 71, 72, 73 and 74 are electrically connected to insulated leads 61, 62, 63 and 64 respectively. Insulated electrical leads 65 and 66 are passed through container tube 90 and are electrically connected to metallic leaf springs 11 and 16 through affixing means 12 and 14 so disposed as to provide electrical contact throughout their length. Into leaf spring 11 there are set electrical contacts 81 and 82 into leaf spring 16 there are set electrical contacts 83 and 84.

In this modification of the invention these electrical contacts are disposed in electrical contact with the leaf springs in which they are set and not electrically insulated therefrom.

Thus, in the position illustrated in FIG. 7 there is provided electrical contact between leads 61 and 65 through the electrical contacts 81 and 71. Similarly there is provided electrical contact between leads 66 and 64 through contacts 84 and 74. However, when the handle 79 is pulled down, the device will LII rotate to the position illustrated in FIG. 8. During this rotation the leaf springs 11, and 16 will snap over center to "break" the aforementioned contact point and at the same time make" the contact pairs 72, 82 and 73, 83.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefor, that the scope of the invention be limited, not by the specific disclosure herein, only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A snap switch including:

an elongated bar section having a predetermined length and first and second ends thereof;

a first leaf spring strip having a length greater than said predetermined length, said first strip being disposed on a first side of said bar section and secured thereto at said first and second ends thereof; said strip tending naturally to assume a concave configuration relative to said first side of said bar section and force applying means applied at a first position thereon to provide first and second curved portions, said force applying means when applied at a second position thereon providing a third and fourth curved portions, said first and fourth curved portions being provided adjacent to said first end of said bar section and said second and third portions being provided adjacent to said second end of said bar section, said first and third portions being shorter and lying closer than said second and fourth portions respectively to said bar section; and

said force applying means and said bar section slidable relative to each other to alternately apply a force to said first and second positions respectively on said first strip.

2. The switch as defined in claim 1 also including:

a first contact mounted on said first strip; and

a second contact mounted on said first side of said bar section adjacent to said first contact so that said first and second contacts make and break continuity as said force applying means is applied to said first and second positions of said first strip.

3. The switch as defined in claim 2 in which said force applying means includes:

a holding member slidable along said first strip from said first position to said second position on said first strip.

4. The switch as defined in claim 3 in which said first and second positions are disposed on opposite sides of the center of said first leaf spring strip along said length thereof.

5. The switch as defined in claim 1 also including:

a second leaf spring strip having a length greater than said predetermined length, said second strip being disposed on a second side of said bar section and secured thereto at said first and second ends thereof; said strip tending naturally to assume a concave configuration relative to said second side of said bar section second force applying means applied at a first position thereon to provide fifth and sixth curved portions, said second force applying means when applied at a second position thereon providing seventh and eighth curved portions, said fifth and eighth curved portions being provided adjacent to said first end of said bar section and said sixth and seventh portions being provided adjacent to said second end of said bar section, said fifth and seventh portions being shorter and lying closer than said sixth and eighth portions respectively to said bar section; and

said second force applying means and said bar section being slidable relative to each other to alternately apply a force, to said first and second positions respectively on said second strip.

6. The switch as defined in claim 5 also including:

a first contact mounted on said first strip;

a second contact mounted on said first side of said bar section adjacent to said first contact so that said first and said force applying means comprising a first holding member slidable along said first strip from said first position to said second position on said first strip; and

said second force applying means comprising a second holding member slidable along said second strip from said first position to said second position on said second position on said second strip.

Claims (6)

1. A snap switch including: an elongated bar section having a predetermined length and first and second ends thereof; a first leaf spring strip having a length greater than said predetermined length, said first strip being disposed on a first side of said bar section and secured thereto at said first and second ends thereof; said strip tending naturally to assume a concave configuration relative to said first side of said bar section and force applying means applied at a first position thereon to provide first and second curved portions, said force applying means when applied at a second position thereon providing a third and fourth curved portions, said first and fourth curved portions being provided adjacent to said first end of said bar section and said second and third portions being provided adjacent to said second end of said bar section, said first and third portions being shorter and lying closer than said second and fourth portions respectively to said bar section; and said force applying means and said bar section slidable relative to each other to alternately apply a force to said first and second positions respectively on said first strip.

2. The switch as defined in claim 1 also including: a first contact mounted on said first strip; and a second contact mounted on said first side of said bar section adjacent to said first contact so that said first and second contacts make and break continuity as said force applying means is applied to said first and second positions of said first strip.

3. The switch as defined in claim 2 in which said force applying means includes: a holding member slidable along said first strip from said first position to said second position on said first strip.

4. The switch as defined in claim 3 in which said first and second positions are disposed on opposite sides of the center of said first leaf spring strip along said length thereof.

5. The switch as defined in claim 1 also including: a second leaf spring strip having a length greater than said predetermined length, said second strip being disposed on a second side of said bar section and secured thereto at said first and second ends thereof; said strip tending naturally to assume a concave configuration relative to said second side of said bar section second force applying means applied at a first position thereon to provide fifth and sixth curved portions, said second force applying means when applied at a second position thereon providing seventh and eighth curved portions, said fifth and eighth curved portions being provided adjacent to said first end of said bar section and said sixth and seventh portions being provided adjacent to said second end of said bar section, said fifth and seventh portions being shorter and lying closer than said sixth and eighth portions respectively to said bar section; and said second force applying means and said bar section being slidable relative to each other to alternately apply a force to said first and second positions respectively on said second strip.

6. The switch as defined in claim 5 also including: a first contact mounted on said first strip; a second contact mounted on said first side of said bar section adjacent to said first contact so that said first and second contacts make and break continuity as said force applying means is applied to said first and second positions on said first strip; a third contact mounted on said second strip; a fourth contact mounted on said second side of said bar section adjacent to said third contact so that said third and fourth contacts make and break continuity as said second force applying means is applied to said first and second positions on said second strip; said force applying means comprising a first holding member slidable along said first strip from said first position to said second position on said first strip; and said second force applying means comprising a second holding member slidable along said second strip from said first position to said second position on said second position on said second strip.

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