US3135841A

US3135841A - Snap acting switch

Info

Publication number: US3135841A
Application number: US834451A
Authority: US
Inventors: Donald E Miller; Roger F Miller
Original assignee: Dole Valve Co
Current assignee: Dole Valve Co
Priority date: 1959-08-18
Filing date: 1959-08-18
Publication date: 1964-06-02
Anticipated expiration: 1981-06-02

Description

June 2, 1964 N. MILLER 3,135,841

SNAP ACTING SWITCH Filed Aug. 18, 1959 3 Sheets-Sheet l [HVEHXUP NICHOLAS M/LLEE- DEC. 5) DOA/ALB E M/LLEE E0852 E M/LLEE EXECS.

June 2, 1964 .N. MILLER 3,135,841

SNAP ACTING SWITCH Filed Aug. 18, 1959 5 Sheets-Sheet 2 June 2, 1964 N. MILLER 3, ,8

SNAP ACTING SWITCH 3 Sheets-Sheet 3 Filed Aug. 18, 1959 F'z 5 j a B) DONALD E. M/LLEP EOGEE E M/LLE,Q EIXEC'S. EU M fijj 5.

, zmg 'izqa r United States Patent SNAP ACTING SWITCH Nicholas Miller, deceased, late of Chicago, Ill, by Donald E. Miller, Mount Prospect, and Roger F. Miller, Chicago, 111., coexecuters, assignors to The Dole Valve Company, Morton Grove, Ill., a corporation of Illinois Filed Aug. 18, 1959, Ser. No. 834,451 2 Claims. (Cl. 209-67) This invention relates to snap action mechanisms and more particularly relates to a double throw snap action mechanism having a neutral or off position.

Snap action mechanisms have found great utility in recent years since they are relatively simply and economically manufactured and since they are operable to actuate the mechanism with which they are associated with a positive stroke of the snap blade even though the force which acts to actuate the mechanism is applied very slowly. More particularly such snap action mechanisms have found particular utility in the electrical field in the form of double throw snap action switches s'uice the quick snapping action of the snap blade associated with the mechanism is efllective to substantially eliminate arcing between two adjacent contacts.

Heretofore, however, such snap action mechanisms have been simply of the single or double throw type having no provision for maintaining the snap blade associated with the mechanism in an intermediate P sit on- Those skilled inthe art of designing and using snap action mechanisms and particularly those acquainted with the adaptability of same to the electrical field will recognize the desirability of providing a snap action mechanism having a neutral or oil position so that, in essence, a triple throw rather than the usual double throw switch is provided.

The invention relates to a switch mechanism wherein the snap blade associated with the mechanism is movable to any one ofthree selected positions as desired. Two embodiments of such a mechanism are hereafter set forth and described with particulartiy and illustrated in the appended drawings.

In the first embodiment of the invention, the snap action mechanism is shown as comprising generally a mounting plate upon which are afiixed two transversely spaced electrical contacts which have a movable contact disposed therebetween. The movable contact is snapped into engagement with one or the other or the two stationary contacts by the usual actuator lever and overcenter spring but has an abutment member associated therewith which is connected to the actuator lever and which is ellective to hold the movable contact out of engagement with one of the stationary contacts in one position of the actuator lever. Upon depressional movement of the actuator lever the movable contact, which is initially disposed in engagement with the lower of the two stationary contacts is snapped upwardly into engagement with the upper of the two stationary contacts. Upon further depressional movement of the actuator lever, however, the abutment member which is connected to the actuator lever and which is engageable with the movable contact moves into'engagement with the movable contact to move the same out of engagement with the upper of the two stationary contacts. Since, however, the movable contact is not moved by the abutment member to a position past the overcenter position of the overcenter spring the movable contact is not thereby snapped into engagement with the lower of the two stationary contacts but is, rather, held in an intermediate or neutral position between the two stationary contacts.

The second embodiment of the invention functions on substantially the same principles but in this embodiment depressional movement of the actuator lever acts to first move the movable contact which is initially in engagement with the lower of the two stationary contacts into an intermediate position and, thereafter, further depressional movement acts to permit spring urged movement of the movable contact into engageemnt with the upper of the two stationary conta ts. Thus, in the first embodiment of the invention, the intermediate or neutral position or" the movable contact or snap blade is effected after the actuator lever has been depressionally moved to its fullest extent. On the contrary, in the second embodiment of the invention the neutral or intermediate position of the movable contact or snap blade is effected in an intermediate pivoted position of the actuator lever.

It is, of course, to be understood that such snap action switch mechanisms as are hereinafter disclosed in detail may find utility in other instances than in the electrical field since triple throw switches may, for instance, be used in controlling the movement of a spool valve or the like.

It is therefore a principal object of the present invention to provide a snap action mechanism in which the snap blade associated therewith may be controllably moved to any of three separate positions.

A further object of the invention is to provide a snap action mechanism of the type above described which may be readily and economically manufactured.

Another important object of the invention is the provision of a snap action mechanism wherein the snap blade associated therewith may be moved to any of three separate positions as desired and wherein movement of the snap blade to these respective positions is elfected as a function of the degree of movement of the usual actuator lever associated therewith.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings, where- FIGURE 1 is a partially sectional partially elevational view of a snap action mechanism constructed in accordance with the principles of the present invention and showing the snap blade or movable contact in a first position;

FIGURE 2 is a partially sectioned partially elevational view which is similar in nature to FIGURE 1 but which shows the snap blade in engagement with the other of two opposed electrical contacts;

FIGURE 3 is a partially sectional partially elevational view which is similar in nature to FIGURES 1 and 2 but which shows the snap blade in an intermediate position;

FIGURE 4 is a fragmental partially sectioned partially elevational view of the snap action mechanism illustrated in FIGURES 1-3 which is taken along lines IVIV of FIGURE 1;

FIGURE 5 is a partially sectioned partially elevational View of a second embodiment of the snap action mechanism of my invention showing the movable contact in a first position;

FIGURE 6 is a view similar in nature to FIGURE 5 but which shows the movable contact in an intermediate position; 7

FIGURE 7 is a view similar to FIGURES 5 and 6 which shows the movable contact in engagement with the other of the two opposed stationary contacts;

FIGURE 8 is a partially sectioned partially elevational view of the snap action mechanism illustrated in FIG- URES 57 which shows the mechanical transducer in side elevation and which is taken along lines V[[[V]I[ of FIGURE 5; and

FIGURE 9 is a view which is similar in nature to FIGURE 8 but which shows the mechanical transducer in a difierent position from that illustrated in FIGURE 8 and which is taken along lines IXD( of FIGURE 7.

, V In the embodiment of the invention illustrated in FIGURES l-4, a snap action mechanism is shown by way of example, and not by way of limitation, being adapted for. use as a double throw electrical switch mechanism and includes generally a snap or actuator lever 11, a snap blade or movable contact 12, and an overcenter spring 13 interconnecting the free end portions of the lever 11 and the blade 12. A supporting member or plate 14 serves to mount the various parts of the snap action mechanism and has an L-shaped bracket 15 mounted adjacent one end thereof which, in turn, serves as a mounting means for the actuator lever 11 and the snap blade 12. The bracket 15 is apertured at the upper end thereof to receive one end of the actuator level 11. The lever 11 has its end which is disposed adjacent the aperture in the bracket 15 turned downwardly as at 16 to prevent movement of the lever out of the aperture by the overcenter spring 13. The free end of the lever 11 has a downwardly turned arm 17 formed integrally therewith which is bent to form a recess 18 adjacent the lower end thereof.

The snap blade 12 is secured to the base portion of the L-shaped' bracket 15 by means of a rivet 19 and has its outer free end connected with the depending arm 17 of the lever 11 by means of the overcenter spring 13.

disposed within the recess 18 in the depending arm 17 and has its opposite end portion received within a spring retaining cup 20. The spring retaining cup 20 has a recess 21 formed within the outer surface thereof which is adapted to receive the free end of the snap blade 12.

A pair of transversely spaced

electrical connecting tabs

23 and 24 are mounted within suitable apertures on the supporting plate 14 and have

contacts

25 and 26, respectively, mounted therein. Obviously, where the snap action switch mechanism is being used as an electrical switch it would be necessary to form the supporting plate 14 of some insulating material. The connecting

tabs

23 and 24 each have protruding

legs

27 and 28, respectively, ex-

tending rearwardly from the supporting plate 14 which are adapted to be connected to electrical power transmission lines. Thus, by connecting the bracket 15 to the opposite side of an electrical power line a current may be transmitted through the tab 27 or the tab 28 as desired by merely moving the snap blade 12 into engagement with one or the other of the two

contacts

25 and 26.

As is well known in the art the snap blade 12 is moved into contact with one or the other of the two

stationary contacts

25 and 26 as a function of the position of the actuator level 11. Thus, when the actuatorlever 11 is in an extreme clockwise rotated position such as is shown in FIGURE 1, the overcenter spring 13 acts to urge the snap blade 12 into engagement with the lower stationary contact 26. When the point of contact of spring 13 with the actuator lever 11 is moved to a point below the point of contact of the spring retainer 20 and the blade 12 by depressional movement of the actuator lever 11, the overcenter spring 13 acts to snap the blade 12 out of engagement with the lower stationary contact 26 and into engagement with the upper stationary contact 25 thus opening the circuit through the tab 28 and closing the electrical circuit through the tab 27.

It will here be noted that depressional movement of the actuator lever 11 may be effected by means of a plunger 30 such as is illustrated in the drawings or in any other suitable manner. In this regard it will be understood that the plunger 30 may be'connected to the actuator lever 11'so that upward movement of the plunger Will act to return the actuator lever 11 and its associated parts to the position illustrated in FIGURE 1 or that the plunger 30 and/ or the lever 11 may be provided with suitable spring means operable to normally bias the various partsof the snap action mechanism to the position illustrated in FIGURE 1. The means 'foreffecting pivotal movement of a the actuator lever 11 do not, however, form a part of the 7 The overcenter spring 13 has one outturned end portion present invention and so will not herein further be demechanisms are generally so arranged that the snap blade is only movable to one of two opposed positions. The invention, however, relates to a switch mechanism wherein the snap blade may controllably be held in an intermediate position between the two opposed

stationary contacts

25 and 26. Toeifect this desirable feature, an abutment member 31 is disposed in sliding contact with the supporting member 14 and has a pair of

opposed convex lips

32 and 33 which are adapted to snugly engage the actuator lever 11. A nib 36 extends rearwardly from member 31 and slides within a slot 37 formed in the'member 14 to guide the member 31 through its path of movement in a vertical plane. An integral depending leg 34 of the abutment member 31 extends through a guide slot 35 in the connecting tab 27 to act as a further guide for the member 31 and is engageable with the snap blade 12 to hold the same out of contact with the stationary contact 25. A rearwardly extending tab 36 is also formed integrally with the abutment member '31 and is slidable within a longitudinal guide slot 37 formed in the supporting member 14.

As a result of the configuration of the abutment member 31 and its cooperation with the actuator lever'11 depressional movement of the lever from the position illustrated in FIGURE 2 to the position illustrated in FIG- URE 3 will beelfective to move the abutment member 31 into engagement with the snap lever 12 and to subsequently move the snap lever out of engagement with the stationary contact 25. n

In operation the snap action mechanism which is illustrated in FIGURES 1-4 functions substantially as follows: Assuming that the actuator lever 11 is initially in the position illustrated in FIGURE 1, the snap blade 12 will be maintained in contact with the stationary contact 26 by the biasing force of the overcenter spring 13 so that the electrical circuit through contact 26'will be closed. Depressional movement of plunger 30 will act to pivotally move the actuator lever 11 with respect to the bracket 15 to effect compression of the overcenter spring 13. When the point of contact of the overcenter spring 13 with the actuator lever 11 has moved to a point below the point of contact of the spring retainer 20 with the snap blade 12, the overcenter spring will act to snap the outer free end of the blade 12 upwardly out of engagement with thecontact 26 and into engagement with contact 25..

Further depressional movement of plunger 30 will act to further pivotally move the actuator lever 11 in a counterclockwise direction about the bracket 15 thereby moving 'the abutment member 31 into engagement with the snap blade 12 and subsequently moving the free end of the snap blade 12 out of. engagement with stationary contact 25. Accordingly, the free end of the snap blade 12 will simply be held by the abutment member 31 in an intermediate position between the

stationary contacts

25 and 26 so that 7 an electrical energizing circuit through each of the contacts will at the same time be opened.

In order to maintain the various interconnected parts in an operative relation with respect to one another, I provide a stop 35a on the supporting member 14 for limiting pivotal movement of the actuator lever 11. The stop 35a has upper and lower outwardly extending

arms

36a and 37a formed integrally therewith and embracing the actuator lever 11 which are adapted to limit the degree of pivotal movement of the lever.

Referring now more particularly to the embodiment of the invention illustrated in FIGURES 5-9, a snap action switch mechanism is shown which is somewhat similar to the embodiment of the invention illustrated in FIGURES 1-4 (like parts having like numerals) but in which the means for holding the snap blade 12 in a neutral position differ somewhat. In this embodiment of the invention the switch mechanism is so constructed that depressional movement of the plunger 30 acts initially to move the snap blade to an intermediate position whi-e further depressional movement of the plunger acts to move the free end of the snap blade 12 into engagement with the upper stationary contact 25. Thus, the cycle of movement of the snap blade is different from that which is effected by means of the mechanism illustrated in FIGURES 1-4.

As shown especially in

FIGUES

8 and 9, a mechanical transducer 50 is substituted in place of the abutment mem ber 31 for holding the snap blade 12 in a neutral position and functions on a different principle. A mounting bracket 51 is rigidly secured to the supporting member 14 and has an apertured outwardly extending flange 52 formed integrally therewith. A pivot pin 53 extends through the aperture in outturned flange 52 and is adapted to rotatably receive the apertured ripper arm 54 of the mechanical transducer 50. A friction spring 53a is disposed intermediate the head 53b of the pin 53 and the transducer 50 which fricticnally engages the transducer 50 to retard pivotal movement thereof. The mechanical transducer 50 also has a lower arm 55 formed integrally therewith which, in turn, has a depending abutment leg 56 extending therefrom which is adapted to engage the outer free end portion of the snap blade 12.

It will be understood that the mechanical transducer 50 is so formed that, when the transducer is in the position illustrated in FIGURE 8, the inner edge of the upper arm 54 extends substantially horizontally while the 111L161 edge of the lower arm 55 extends angularly upwardly toward the outer end of the arm forming a cam face for reasons which will hereinafter become apparent. The actuator lever 11 is adapted to be disposed in the space intermediate the upper and

lower arms

54 and 55, respectively, of the mechanical transducer 50 and the end portions of the arms are so spaced from one another that the lever has limited relative freedom of movement between the arms. That is, the distance intermediate the outer end portions of the respective arms of the mechanical transducer is so fixed that the lever 11 can move from the position illustrated in full lines in FIGURE 8 to position A illustrated in broken lines therein without caus ng pivotal movement of the transducer 50. It will be understood that the position of the actuator lever 11 which is shown in full lines in FIGURE 8 is the same position of the lever as is shown in FIGURE 5 and that position A of the lever is the same as the position of the lever shown in FIG- URE 6.

The inclined inner edge of the lower arm 55 acts as a cam surface so that when the lever 11 is depressionally moved from position A in FIGURE 8 to position B therein, the mechanical transducer 50 will be pivotally moved about the pin 53 to the position illustrated in FIGURE 9. Depressional movement of lever 11 is limited by means of a stop arm 58 formed integrally with the bracket 51 and upward movement of the lever is similarly limited by a projecting portion 59 of the bracket 51.

When the actuator lever 11 is in the position illustrated in FIGURE 5 and in full lines in FIGURE 8, the snap blade 12 will be positioned with its outer free end portion in engagement with the lower stationary contact 26 and will be positioned relative to the depending leg 56 of the transducer 50 as indicated in full lines in FIGURE 8. Depressional movement of the plunger 30 will act to pivotally move the actuator lever 11 in a counterclockwise direction about the bracket 15 to an overcenter position with respect to the point of engagement of the spring retainer with the snap blade 12 so that the blade 12 will be snapped upwardly out of engagement with the stationary contact 25. The snap blade will not, however, move into engagement with the upper stationary contact but will be held in an intermediate position between the two opposed stationary contacts by means of the depending abutment member 56 since it will at that point be disposed in the path of movement of the blade 12. Further depressional movement of the plunger 30 will act to still further move the actuator lever 11 in a counterclockwise direction about the bracket 15 until it moves into engagement with the stop arm 58. Such movement of the lever 11 from position A to position B as shown in FIGURE 8 will act against the inclined cam surface of the mechanical transducer 50 to pivotally move the transducer in a counterclockwise direction about the pin 53 thereby moving the abutment member 56 out of engagement with the snap blade 12 and permitting upward movement of the outer free end of the snap blade 12 into engagement with the upper of the two opposed stationary contacts 25 as is clearly shown in FIGURES 7 and 9.

As hereinbefore mentioned, it is important to note that such a snap action mechanism may find great utility in other fields than the electrical field such as, for instance, where a snap action mechanism is to be associated with a fluid control valve to control the movement of a spool valve or the like.

Also, as a matter of interest, movement of the plunger 30 may be effected by means of a thermally sensitive power element and in such case the plunger 30 might comprise the power member or piston of the thermally sensitive element which is extensible from the body of the power element upon fusion or expansion of the thermally sensitive material therein. This, of course, constitutes no part of the present invention but is noted as of interest.

It will herein be understood that these embodiments of the invention have been used for illustrative purposes only and that various modifications and variations of the present invention may be effected without departing from the spirit and scope of the novel concepts thereof.

What is claimed as the invention:

1. A snap action switch mechanism comprising a mounting member, a pair of transversely spaced brackets afiixed to said mounting member, contacts on each of said spaced brackets, a resilient contact blade disposed intermediate said spaced contacts, an actuator lever pivotally mounted on said member, biasing means interconnecting said lever and said blade for selectively snapping said resilient contact blade toward one of said spaced contacts, and means comprising an extension from said lever engageable with said resilient contact and guided within at least one of said brackets operable to prevent engagement of said resilient contact with one of said spaced contacts even though said resilient contact is biased toward said one of said spaced contacts and away from the other of said spaced contacts.

2. A snap action mechanism comprising a mounting member, a resilient blade mounted on said member, an actuator lever pivotally mounted on said member, resilient means interconnecting said lever and said blade for biasing said blade selectively toward one of two opposed extreme positions as a function of the pivoted position of said lever, and means comprising an extension from said lever engageable with said resilient blade to hold said resilient blade in an intermediate position between the two opposed extreme positions of said blade.

References Cited in the file of this patent UNITED STATES PATENTS 2,586,075 Miller Feb. 19, 1952 2,783,323 Jeffrey Feb. 26, 1957 2,792,466 Raney May 14, 1957 2,798,127 Roeser July 2, 1957 2,846,538 Hager Aug. 5, 1958 2,872,540 Hager Feb. 3, 1959 FOREIGN PATENTS 490,372 Germany Jan. 30, 1930

Claims

2. A SNAP ACTION MECHANISM COMPRISING A MOUNTING MEMBER, A RESILIENT BLADE MOUNTED ON SAID MEMBER, AN ACTUATOR LEVER PIVOTALLY MOUNTED ON SAID MEMBER, RESILIENT MEANS INTERCONNECTING SAID LEVER AND SAID BLADE FOR BIASING SAID BLADE SELECTIVELY TOWARD ONE OF TWO OPPOSED EXTREME POSITIONS AS A FUNCTION OF THE PIVOTED POSITION OF SAID LEVER, AND MEANS COMPRISING AN EXTENSION FROM SAID