US2521277A

US2521277A - Snap acting device

Info

Publication number: US2521277A
Application number: US670479A
Authority: US
Inventors: Fred B Aubert
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-05-17
Filing date: 1946-05-17
Publication date: 1950-09-05
Anticipated expiration: 1967-09-05

Description

Sept. 5, 1950 F. B. AUBERT SNAP ACTING uEvIcE 2 Sheets-Sheet 1 Filed Hay 17, 1946 INVENTOR.

5L/u@ M BY M ATTORNEY Sept. 5, 1950 F. B. AUBERT SNAP ACTING DEVICE 2 Sheets-Sheet 2 Filed May 17, 1946 FIGA .lll 1|] IN V EN TOR.

Maw/KM A, AT TORNEY\ Patented Sept. 5, 1950 UNITED STATES PATENT oFElcE 2,521,211 sNAPAoTmG nEvIoE Fred n. Aubert, Detroit, Mich. Application May 17, 194e, serial No. 670,419

4 claims. (ci. zoo-c1) This invention relates to new and useful improvements in snap-acting devices wherein a control means such as a valve or switch is quickly moved to or from a desired position.

An object of the invention is to provide a structure in which the control means is .positively movable by a direct thrust thereby obviating sticking of the control means against movement.

Another object is to provide means to impart a shock or blow to the control means to dislodge it from a stuck position.

Another object is to provide a'switch structure in which the contact members have a rolling action upon engagement thereby reducing the tendency of the contact members to fuse together.

The invention consists in the new and improved construction and combination of parts to be more fully described hereinafter and the novelty of which will be particularly Ipointed out and distinctly claimed.

In the accompanying drawings to be taken as a part of this specification, there are fully and clearly illustrated several preferred embodiments oi the invention in which drawings:

Figure 1 is a view in side elevation of a snap acting switch mechanism having the casing cover member in section to show the switch structure embodying the invention,

Fig. 2 is a plan view in section on the line 2-2 of Fig. l,

Fig. 3 is a view similar to Fig. 1; but showing the switch mechanism in an operating position.

Fig. 4 is an enlarged detail view showing the various stages of switch structure movement during the operation of the switch mechanism.

Fig. 5 is a detail view in section on the line 5--5 of Fig. 3,

2 mounting platform. Clamped to the top face of the platform l there is a furcated substantially rectangular resilient arm -5 .of sheet metal which extends longitudinally of the base member and carries at its free end a control means or switch contact member 6. Also secured to the supporting platform I between the side arms of the ence in a direction away from the base member.

Fig. 6 is a view in side elevation of a snapacting valve mechanism also embodying the invention, f

Fig. 7 is a view in side elevation of another form of switch structure and showing the parts in an intermediate position, and

Fig. 8 is a diagrammatic view of another form of snap switch mechanism.

'Referring to the drawings and particularly Figs. l to 5, i designates a base member of electric insulating material preferably of elongated rectangular form having a peripheral seat or shoulder 2 to receive a hollow cover member 3 also of electric insulating material. The base member i is provided with an elevated supporting portion d adjacent one of its ends and which entends across the base member to provide a The arms 5 and I are lpreferably formed as by stamping from a single sheet of metal so that they are joined at their end portions which are clamped by a plate 8 and screw 9 to the plat- .form 4. The free end portion I0 of the arm ti,

to which the contact member d is secured has intermediate the side arms or members, a tongue or projecting portion II directed toward the free otally connected to or fulcrumed on the arms t n and 1. It will thus be seen that the arms 5 and 1 and the spring I3 provide three movable members which are stressed against each other to form an over-center snap-acting mechanism which functions to quickly move the arm 5 when the point of connection between the arm 'I and spring I3 is moved through the line connecting the point of pivotal engagement of the spring i3 with the arm 5 and the point or line of connection of the arm 5 to the supporting platform d.,

Cooperable with the contact member 6 there is a xed switch contact member I 4 which is carried by a metal bracket or plate member i5 which is supported on a post I6 of electric insulating material which is rigidly secured to the base member I by a hollow rivet I'I which projects from the underside of the base member and is internally screw threaded to receive a terminal or binding post screw Id.

The coverv member 3 is provided with a stop member I9 which extends into the casing in overlying relation to the spring i@ and for en-a gagement thereby. It will be noted that the stop member or pin Il@ is positioned so that its point of engagement with the spring it is protected by the curvature of the spring from straight line relation to the surface engagement or point of contact between the contact members l and Il. The surface portion of the spring Il which is engageable with the stop member Il is thus protected by the interposed spring portion 2l from any impingement thereon oi' particles of the switch contact material which might roughen the abutment engaging portion of the spring surface. Roughness of this spring portion surface would impede free slippage of the spring Il on the abutment member I9. The cover member is rigidly secured in position by cross pins 2l. Also carried by the cover member there is a switch operating thrust member or pin 22 having a button or head portion 23 within the switch casing and which rests on the top face of the arm 1. The pin 22 is guided for longitudinal reciprocatlon in a guide aperture 23a through the cover member 3 and may be operated by any desired means such as a bimetal heat motor, a relay armature or the like. cient strength so that it acts by its inherent resilience under the force of the arm 1 to bow or bend the contact carrying arm l slightly downward in the position of Fig. 1 and such that when the parts are in the position of Fig. 3, the arm 5 will be bowed or bent slightly upward. This bowing or bending of the arm 5 results in the contact member 6 engaging the contact member I4 with a-rolling action thereby reducing the tendency of the contact members to fuse and adhere to each other upon making contact. The

The spring II has sufiiclamping screw 3 is threaded into a metal tube 2l which projects from the underside of the base member I and receives a terminal screw or binding post to receive one lead wire, the other' lead wire being connected to the terminal Il.

The operation of the switch oi Figs. 1 to 5 is as follows: When the pin 22 is depressed or moved inward into the casing against the force of the spring blade or the arm 1 and the expansive force of the spring I3, the point of engagement between the arm 1 and spring I3 will be moved downward or toward the arm l. As` the point of engagement between the arm 1 and spring I! moves through the center position or crosses 'the plane of the arm 5, the force .of the spring I3 will exert an upward component on the arm 5 and snap or quickly move the arm l into engagement with the contact member Il. The engagement of the contact member 5 with the contact member Il will be as above noted, with a. rolling action of the surface of the member l on the convex surface of `the member Il. Because of the bias of the arm 1 to its position in Fig. 1, the arm 5 will be held in its contact making position only so long as the pin 22: is exerting suilicient force to overcome the force of the arm 1. When the for exerted on and through the pin 22 is release for switch breaking movement, the spring arm 1 will move fromJ its full line position, Fig. 4, and when it crosses the-line of the arm l there will be a downward component of force exerted by the spring Il so that in normal operation when the arm 1 has moved say to the dash-dot line position, the spring I3 will be exerting sumcientforoe to move the arm 5 quickly downward to the switch open position as indicated vby the dotted line of the arm 5 and contact member 5 in Fig. 4. In this dash-dot position of the arm 1, the spring Il is also in the dash-dot position and has just come into engagement with the stop member I O. Accordingly any further upward movement of the l 4 srm'lwmcwetnuprmg utocamurplvot on the stop member Il so that there is a-direct thrust of the spring Il against the arm l. I'his direct thrust by the spring Il against the arm l is sufficient to breaky the contact member l away from the contact member Il in the event that these contact members might have fused and stuck together. In addition to the direct thrust exerted by the spring II, the force exerted by the inherent resilience of the arm 1 and the upward component of the end of the spring Il engaging the arm 1, cause the spring Il to strike against the abutment member with a sharp hammer blow which by its reaction through the spring I3 further serves to break apart the contact members C and I I ii they tend to stick together.

Referring to Fig. 6, 3i designates a valve casing having a valve port orpassageway )I controlled by a valve member l2 which is carried by an operation arm 33. A stop member Il is preferably provided to limit opening of the valve member and travel of ythe arm Il which is pivoted at 35. Cooperable with the arm 32 there is an expansion spring Il which is laterally supported for longitudinal expansion and compression within a capsule or tubular member 31 having a reciprocal end portion 3l guided in the tubular portion and holding the spring It under compression. The spring supporting member l1 has its opposite ends terminating in conical tips which are received respectively in an arm or abutment member 3S rigid with the arm 33 and a flange or abutment member 40 rigid with a lever arm II pivoted at I2. The three members 3l, I1 and Il are therefore held under tension against each other by the force of the spring' 35. The point of pivotal engagement 45 of the expansible member l1 with the abutment member Il is positioned overcenter with respect to the line connecting the point M of pivotal engagement between the member 31 and abutment member ll and the pivot I5 for the arm Il. Accordingly the spring l5 is exerting aeomponent of its force to urge the valve member 32 against its seat and closing the port ll. The lever arm II is urged to the position of Fig. 6 by a spring l5 and is limited4 Y ward and overcenter. As soon as the point moves overcenter, lthe spring 3l will exert a component of its force in an upward direction on the arm and snap or quickly move the valve member I2 to open position against its stop member 5l. Upon movement of point Il overcenter, the member 31 will laterally engage thevstop or abutment member Il with a hammer blow to dislodge the valve member vand will thereupon rock or pivot on the member Il so that the member 31 under the force of the heat motor I1 will exert a positive direct thrust against the lever arm )lso that the, valve member I2 will be positively moved toward open position and prevented from sticking in closed po sition. The return movement of the valve member I2 to closed position under the force of the spring ll when the heat motor is deenergised and cools, will occur when the point Il moves through the line connecting the point 44 and the pivot point 42.

Referring to Fig. 7, there is a, casing 50 having a xed switch contact member I with which a moving( contact member 52 cooperates, A lever arm 53 carries the contact member 52 and is pivotally supported 'on a fulcruminember or pin 54.'l Extending longitudinally of the arm 53 there is an operating arm 55 of resilient material which is bent or bowed as at 56 so that it tends to expand longitudinally. The arm 55 is also pivoted on the pin 54 and extends longitudinally of the arm 53 with its free end portion 51 terminating in spaced relation to an abutment portion 58 on the arm 53. Pivotally engaging the end portions 51 and 58 and held under compression therebetween there is an overcenter member 59 which upon overcenterV movement for switch opening movement engages a stop member 60 carried by the casing 50. The overcenter member 59 is urged downward or to switch closing position :by a coil spring 6| mounted and guided in the casing 50. Also cooperable with the member 59 there is an operating pin or thrust member 62 which is operable on inward movement to overcome the spring 6i and rotate the member 59 about theabutment vmember 60 so as to exert a positive direct thrust against the lever arm 53. The mem-

bers

53, 55, 59 are held under tension against each other by the spring portion 56. In the position of the parts in Fig. '1, the thrust members 62 has moved the arm 59 upward from the position in which it is normally held by the spring 6l, the position of the parts being an intermediate one such as would occur with sticking of the contact members 5i and 52 together with suilicient force so that the downward component of force of the spring portion 56 could not break them apart. Any further upward movement or inward 'movement of the member 52 into the casing will rock the member 59 upon the stop member 60 and force the member 52 away from its contact member 5i.

Referring to Figure 8, the switch structure is generally similar to that of Fig. 1, but-has the U-shaped or bowed leaf spring 10 inverted and has the contact carrying end portion 1l of the leaf spring or arm 12 bent or inclined to the main portion of the arm, so that its contact member 13 will engage the fixed contact member 1t with a sliding or wiping action. The spring 1t is held under compression between the arm 12 and the operating arm or leaf spring 15 which is biased in an upward direction or toward the contact member 14 so that it normally tends to l position the spring 1l) to urge the arm 12 out of contact making position or away from the contact member 14. Straddling the leaf spring 19, there is an operating means 16 which is a U-shaped lever pivoted oli center, at 11, so that the leg 18 normally rests by gravity on the arm 15. The other leg 19 is engageable with the contact carrying lever 12 and the relation of the

parts

15, 16 and 12 is such that when the

contact members

13, 14 are in engagement, the

legs

18 and 19 have simultaneous engagement with the arms and 12 respectively, but only subsequent to movement of the arm 15 through center position on its contact separating movement. Therefore, if the

contact members

13 and 14 tend to fuse or stick together, the force of the -arm 15 is transmitted through the lever 16 and directly upon the lever 1,2 to move positively the contact member 13 away from the contact mem-` ber 14. Cooperable with the arm 15, there is an operating pin or plunger 80, guided in the casing 8l and operable to depress the arm 15 against its inherent resilience or bias. The pin is operable to move the arm 15 over or through center so that the arm 15 is positioned on the opposite side of arm 12 from that shown in Fig. 8 and therefore moves the spring 10 over-center so that its reaction component acts upward on the arm 12 and snaps or quickly moves the contact member 13 into wiping or sliding engagement with the contact member 14. It may be noted that upon release of the pin 80, the spring 15 strikes the lever 16 and thus imparts a hammer blow to the arm 12 which in addition to the direct force exerted on the arm 12 through the lever 16 by the arm 15, assures the sudden breaking of contact between the contact mem-

Ybers

13 and 14.

It will be apparent from the foregoing that there is provided a construction in which the movable control member has a direct thrust imparted thereto to eliminate sticking. By varying the position of the overcenter stop member or the length of the arms of lever 16, the thrust may be caused to occur either simultaneously with initial overcenter movement or subsequent to such initial movement in order to obtain the advantage of a hammer blow or shock imparted to the control member. It should be further noted, however, that the most desirable use of the principle of this invention is as a safety means and that as such the lever action and shock effect would not take place except when there is a failure of the contact members to separate upon normal overcenter action. The fact that the aforementioned use is deemed the most desirable one would not prevent other applications of the principle since by -proper proportioning of parts said lever action could be made to take effect in nany position of movement.

Having thus described the invention, what is claimed and is desired to be secured by Letters Patent of the United States is:

1. In a snap-acting mechanism, a pair of members. one of said members being resilient and of U-shaped form with one leg having pivotal engagement with the other of said pair of members, a third member extending substantially parallel to said other member and having pivotal engagement withthe other leg of said one member, means supporting said third member and said other member for transverse movement of their one member engaging portions, an abutment member in the path of movement of the base portion of said one member, said other member being biased toward said abutment means and operable to move said one member thereagainst with an impact force thereby to transmit the pivotal eii'ect of said impact to said third member, and a control member movable by said third member.

2. A snap-acting switch, comprising a base member, a supporting member spaced from and mounted on said base member, a contact member carried by said supporting member and facing said base member, a resilient arm having one end portion positioned between said supporting member and said base member and having its other end portion secured to said base member. a contact member carried by said arm and engageable with said ilrst-named contact member, a resilient operating arm secured at one end portion to said base member adjacent said other end portion of said first-named arm and having its other end portion biased to move away from said base member and being movable from one side to the other of said first-named arm, a leaf spring bowed concavely toward said 'base member and having its end portions positioned between and tensioned against said arms and having its point of engagement with said operating arm movable through center, a stop member rigid with said base member and positioned for engagement by the convex surface oi' said leaf spring upon movement of said operating arm to the contact member side of said nrst-named arm, said leaf spring having a portion of its surface interposed in the straightline path between the contact engaging surface of said first-named contact member and the portion of said leaf spring engaged by said stopmember so that particles of contact member material will be prevented from impinging the stop member engaged portion of said leaf spring, and a plunger cngageable with and operable to move said operating arm.

3. In a snap-acting mechanism. a resilient arm xed at one end, a control member carried by the other end of said arm, a resilient operating arm xed at one end adiacent said one end of said first-named arm and biased to move in one direction, said arms each having an abutment portion facing each other, a leaf spring bowed to U-shaped form and having its end portions engaging said abutment portions, a stop member positioned in the path of movement of and engageable by the external surface of the base portion of said spring, said operating arm acting to ulcrum said spring on said st'op member to urge said irst-named arm in a direction opposite to said onedirection, means to move said operating arm against its bias and the point of engagement of said operating arm and said leaf spring gagement with the 6 through center position, and said operatim being operable upon release from said overeen movement to move said leaf spring stopmsmberwithanimpacttotransmitto first-named arm a shock force.

4. lnasnap-actingmechanismapairofmem- .oneofsaidmembersbeingresilientandof U-shaped form with one leg having pivotal enother o! said pair of members. a third member extending substantially parallel to said other munber and having pivotal enforce directly from said other member to said third member to supplement the reaction force of said one member.

FRED B. AUBERT.

BH'EBENCES CITED The following references are of record in the nie of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,521,277 September 5, 1950 FRED B. AUBERT It is hereby certified that error appears iii the printed specification of the above numbered patent requiring correction es follows:

Column 8, line 12, strikeout the Words of seid pair of members and insert -\instead Zeg of said one member;

and that the said Letters Patent should be read es corrected above, so that the same may conform to the record of the oase in the Patent Office.

Slgned and sealed this 28th day of November, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'sszoner of Patents.

Certificate of Correction Patent No. 2,521,277 September 5, 1950 FRED B. AUBERT It is hereby certified that error appears in the printed specification of the above numbered patent requiring eorreetien as follows:

Column 8, line 12, strikeout the Words of said pair of members" and insert \\instread Zeg of said one member;

and that` the said Letters Patent should be read as corrected above, so that the same may conform to Jche record of the case in the Patent Oliiee.

Signed and sealed this 28th day of November, A. D. 1950.

[SML] THOMAS F. MURPHY,

Assistant 'ommzssioner of Patents.