US2199357A - Switch - Google Patents

Description

April 1940. E. J. DILLMAN ET AL 2,199,357

SWITCH Filed Dec. 19, 1936 2 Sheets-Sheet 1 INVENTORS BY M 2. Jim? Q TTORNEJ April 30, 1940. E. J. DILLMAN El AL 2,199,357

SWITCH Filed Dec. 19, 1936 2 Sheets-Sheet 2 m A TTOR/VE y Ma -balm "PATENT I oFr-ics mam mat lbillmanandlackll. rum-ammo, mob, alig'liors to Detroit Lnbricator Coilipony, Detroit,Mioh.,acorporation of Michigan Application December in, ms, said No. 110,150

scum. (cuss-1w Ourinvention' relates generally to the method and means for controlling 'an electric circuit and more'particularly to the method of and switch for controlling an electric circuit. One of the-objects of our invention is to provide a new and improved method of closing a switch ;in a manner such'that the time period of usefulness of the switch contacts is materially prolonged.

Another object of our invention is to provide a new and improved switch of a character such that fusing of the contacts is very unlikelyto occur. 7

Another object of our inventionis to provide a switch having anew and improved closingaction to provide good contact between the contact.

members.

Another object of our invention is to provide a.

new and improved switch in which the bouncing or relative vibratory action between the contacts following initial closing of the switch is minimized to aidinavoiding fusing 'oi the contacts.

Anotherobject of our invention is to provide a switch in which, during the bouncing or relative vibratoryaction of the contacts following initial closing of the switch, the contact engaging surfaces engage at successive areas on each of the contact surfaces to still further aid in avoiding fusing of the contacts. V

Another object of our invention is to provide a switch mechanism employing an armature and tlnctly claimed.

In the accompanying drawings, to be taken as a part of this specification, we have fully and clearly illustrated our invention, in which draw- 1ngs- Figure 1 is a side view of a control device embodying our invention, the cover of the device being removed to show thearrangement of the parts, certain of which are shown in elevation and other of which are broken away and shown partly in section;

, Fla. 2 is a view shown in vertical cross section taken along the line 2-2 of Fig. 1; 1

Fig. dis a view shown in perspective of parts of our device including parts of our improved switch;

Fig. 4- is an enlarged view shown in side elevation of parts of our device including our new and improved switch and illustrating the closing action of'our switch, and

Fig. 5 is an enlarged view shown in side elevation of a pair of cooperative contacts of our switch and illustrating the eng ging action of the contacts.

Referring first to Figs. 1 and 2 of the drawings, the control device shown for the purpose of illustrating our invention includes a supporting member, preferably a casing I that is rectangular in shape having a top wall 2, bottom wall 3', side walls 4, i and. end walls 0, I. The casing I is preferably constructed of a good electric insulating material and the side wall 4 thereof is preferably removable as a'cover. The cover 4' may be secured in place by a screw that may screw thread into a boss 8 formed integral of side wall 5.

Carried by the casing l and secured to the bottom wall 3 thereof there is an actuator which, among other types of actuators, may be employed to actuate our hereinafter described switch, the

actuator shown being a pressure responsive power element designated in general by the numeral 10. The power element It is not shown nor described in detail since such devices are well known in the art to which this invention appertains but, in general, such devices comprise an expansible chamber which may include a bellows (not shown) that is usually enclosed in a cap-like casing, as at II, the expansible chamber being communicable with a source of pressure through a fitting ll. Carried by and movable with the bellows there is a thrust rod I! that projects upward into the casing I through an aperture in the casing bottom wall 3. The power element It is operable to move the thrust rod I2 upward and surrounding the rod, within casing I, there is a helical coil spring l3 which, in the present instance, is under compression acting to move the thrust rod l2 downward. The power element l0 and spring I! thus oppose each other and when one overcomes the force exerted by the other, the thrust rod i2 is moved in a corresponding direction. The upper end of the coil spring I! may abut a movably adjustable abutment member I! whichyin the present instance, is in the form of a cap that fits over an upper end portion of the iii spring and at its lower or open end preferably of the abutment member or cap i2 may be adjusted by means of an adjusting screw l2 acting through a lever II. The lever i1 is pivotally supported within casing I, and preferably one end thereof is bifurcated or forked for straddling the cap l2 andhas downwardly directed, pointed, extended portions l2 for engaging in upwardly facing indentations or sockets in the cap flange I 2. The adjustment screw i2 abuts the lever l1 adjacent the fulcrum thereof and may be screw.

threaded into the casing end wall in a manner such that the screw will be accessible from extnally of the casing.

Disposed within the casing I there is a metallic, channel-shaped supporting member 22 that is secured to the casing top wall 2 and overlies thepower element thrust rod l2. The supporting member 20 has a base 2i and spaced, depending, substantially parallel sides or flanges 22, the member 22 being arranged such that its flanges 22 extend longitudinally of the casing i. A shaft 22 has its opposite ends secured in and to the flanges 22 and a movable supporting or carrier member 25 in the form of a lever is pivoted adjacent one of its ends on the shaft 22. The lever 25 is of plate-like form and preferably has downtumed, substantially parallel side flanges 22 that position between the depending side flanges 22 of the supporting member 22 and are provided with aligned apertures to receive the shaft 22. The lever 25 extends longitudinally of the casing I and is provided with an opening 21 therethrough intermediate its ends, as is more clearly shown in Fig. 3, the opening 21 overlying and receiving the upper end of the power element thrust rod I2. Positioned in the opening 21 between the lever side flanges 22 there is a second lever 22, and this lever 22 is preferably constructed of electric insulating material. The lever 22 has a vertical aperture 22 therethrough in which an upper end portion of the power elementthrust rod I2 projects, the rod being pivotally connected adjacent its upper end to the lever 22 by a pin 22. The lever 22 extends longitudinally of lever 25 and has one end, as at 2i, that is disposed toward the shaft 22 of lever 25, and intermediate this end of the lever 22 and the pivot pin 22 the lever 22 is provided with an aperture to receive pins or trunnions 22 secured in and to the depending side flanges 22 of the channel-shaped support 22. An abutment member 22, which may be in the form of a pin, has its opposite ends secured in and to the side flanges 22 of lever 25, intermediate the fulcrums of the levers 25 and 22, and the lever 22, adjacent its free end 2|, rests on the abutment pin 22. when the power element l2 moves the thrust rod t2 upwardly, the lever 22 will be pivoted in a clockwise direction, as seen in Fig. 1, and through the abutment or pin 22 will pivot lever 22 in acounterclockwise direction. The lever 22 has a relatively short lever arm 25 extending toward the casing end wall 1, and acting downwardly on the lever. arm 25 there is preferably a helical coil spring 22 that acts to pivot lever 25 in a clockwise direction. In the present instance, the spring 22 is under compression, one end thereof abutting the underside of the base 2| and the other'end abutting the upper surface of lever arm 25.

Carried by the lever 25 adjacent its free end there is a rigid metallic strip or backing member 22 having a downwardly extending portion 22', a flexible metallic strip or leaf spring 22 and a resilient or flexible metallic strip or blade 22.

The blade 22 is interposed between the rigid strip 22 and the leaf spring 22, the spring being heheath the blade and the strip 22 being above the blade. The rigid strip 22, leaf spring 22 and blade 22 are T-shaped, in the present instance, and the cross pieces thereof are provided with aligning apertures for receiving rivets 22 that secure the strip 22, spring 22 and blade 22 together and to the top of laterally spaced, upwardly extending posts 22 that are carried by and zidly secured to the lever 22 intermediate the ends of the lever. The strip 22, spring 22 and blade 22 are spaced above the upper surface of lever 25 by the posts 22 and extend from the posts longitudinally of the lever toward the free end thereof, the blade ,22 being longer than either the strip 22 or spring 22, and adjacent its free end carrying an upwardly facing contact member 22. The upper surface of the contact member 22 is preferably rounded or convex, as at 22', see Figs. 4 and 5, and the contact 22 cooperates with a depending contact member 22 for controlling an electric. circuit, the contact member 22 preferably having a flat contact surface for engagement by the rounded contact surface 25". As seen in Figs. 1 and 4, the blade 22 is preferably formed such that it extends downward from, and at an angle to its fixed end portion or cross piece that seats on the posts 22. Adjacent its free end the blade 22 is bent in-a manner such that the end portion thereof, as at 21, to which the contact member 25 is secured, extends upwardly from the bend at a slight angle, the purpose of which" is hereinafter described. The leaf spring 22 preferably has a downwardly directed, offset portion 28 intermediate its ends and an end portion of the spring, at its free end, is preferably bent upwardly, as at 22, providing an upwardly fa...ng, rounded or convex surface for engagement with the underside of blade 22. The rounded spring portion 22 provides for a deflnite point of force transmission between the blade 22 and spring 22, and for best vibration dampening results the spring should engage the blade as near the free end of the blade as is practical. The leaf spring 22 preferably is arranged such that it urges the blade 22- upwardly, holding the blade under a slight tension force when the blade is in open circuit position. The leaf spring 22 and blade 22 being of different lengths and shapes have different vibratory frequencies which, together with the friction between the blade and spring, serve to dampen vibrations of the blade and in so doing materially reduces the bouncing action of contact member 25 on contact member 22 on initial engagement of the contact members. The rigid strip 22 is preferably bent having a downwardly extending portion 22' that follows in general the shape of the blade 22 but preferably extends at a slight angle to, or is spaced from the upper face of the blade, as shown.

Carried by the lever 25 and rigidly secured thereto adjacent its free end there is an upwardly extending post 22 that is adapted to engage the underside of the casing top wall 2 for limiting movement of the lever in a clockwise direction, as seen in Fig. 1. A metallic, open ended, tubular fitting or terminal post 52 is preferably secured in and to the top wall 2 in overlying relation to the contact member 22, and in the terminal post 52 the contact member 22, which is preferably in the form of a screw, may be adjustably screw threaded and be accessible from externally of the casing l. The contact member 22 is' adjusted to apoeition suchthatonclosingoftheswitchthe contact member 4| will engagetbe contact member 48 prior to mcnt ofthe stop member llwiththecasingtopwall 2; Becuredtothe tenninaipostflisone endofaconductorinemberor jumper strip ll, which jumper strip, in the present instance, is embedded in the .casing top wall 2, side wall I and bottomwall l. the other endofthejumperstrlpltbeingconnectedtca terminalpostflsecuredinandtothecasing bottom wall 3 adjacent the cover 4. Preferably a jumper wire ll connects the lever 24 and-its metallic supporting member 24, and a jumper wire It connects the supporting member 2. and a terminalpostllthatmaybedisposedinthecasing l adjacent the other terminal post 4. Lead wires from a device, the operation of which may be controlled, may be connected to the main terminals l4 and I1 and when the switch is closed Disposed within the casingl and preferably secured to the casing end wall 6 there is a supporting member 60 that is preferably a resilient, or flexible, plate or hinge member preferably formed of spring metal having a horizontally disposed portion il that is under tension acting to spring upward. The horizontally disposed portion 6| preferably extends from the casing end wall 6 toward and terminates adjacent the free end of lever 25, the horizontal portion BI and lever proper being preferably in substantially the same horizontal plane. The supporting member or spring plate ill may have a downturned flange portion 82 that may be provided with apertures for receiving screws, or other suitable means, for securing the supporting member 60 to the casing end wall 6. Carried by and supported on the upper surface of the spring supporting member 60 there is a magnet 63, preferably of the socalled U-shaped, permanent type. The magnet 3 extends horizontally, or extends substantially parallel with and adjacent the underside of the casing top wall 2, and the magnet is arranged such that its opposite end portions or poles overlie an end portion of the free end of lever 25, which end portion serves as an armature for attraction by the magnet. The magnet 63 is also preferably arranged so that its poles straddle the stop member 50 and the cooperative contact members 45 and 46.

The magnet 63 determines the differential of operation of the switch, and carried by the supporting member 60 there is a manual adjustment means for flexing the supporting member to move the magnet poles closer to or farther away from the lever 25. By changing the distance between the magnet poles and the lever 25 it will be understood that the effective holding force of lar screw II that threadsinto the fitting from the top thereof,the screw-it preferably having a head." beneath which there is preferably a v washer 04 that rests on the upper surface of thethreaded longitudinally am toreceive atubuparallel magnet portions. 'By screw threading the screw It tightly into the fitting II the fitting 4|, magnet 48 and supporting member 44 may be rigidly secured together.

A lower end portion of the fitting II is preferably of enlarged diameter, as at Cl, and extending through this portion of the fitting, transverse tothe-longitudinal axis thereof, there is a manually rotatable adjustment member I! in the form of a pin or shaft. The shaft ll extends through and is journaled in aligned apertures in opposite walls of the fitting I and extends substantially perpendicular to the casing cover 4. The end of shaft 89 that is disposed toward the casing side wall I has an 'annular'slot or recess extemally of the fitting II, and in this recess there is preferably clamped and secured a friction washer 1 end to end with a screw 13 that is adjustably screw threaded into a metallic, open ended, tubular insert member that is secured in and tothe casing top wall 2. The screw 13 may be provided with a slot in its upper end for receiving a screw driver, or other tool for adjusting the position of the screw.- By means of the screw II the resilient supporting member and all the parts carried thereby may be moved upward or downward to the positions desired. The end of the shaft 88 that isdisposed toward the casing cover 4 is provided with an enlarged portion or head 15 that provides an external, annular shoulder li facing toward and spaced from the outer wall surface of the fitting 85. A dial plate It is provided and preferably has an aperture to receive the shaft 69 and positions between the outer wall surface of the fitting and the head or enlarged portion 15 of shaft 89. A pointer member TI is provided and preferably has an aperture to receive the shaft 69 and is disposed between the enlarged portion 15 of the shaft and the face of the dial plate It, the pointer 11 being secured to the shaft for rotary movement therewith. On the face of the dial plate 18 there may be provided suitable'indicia for cooperation with the pointer 11 to aid in determining the desired position of the magnet poles relative to the armature portion of lever 25. It will be seen that the dial l6 and pointer I1 cooperate to indicate the differential of operation of the switch and that the dial and pointer are readily observed upon removal of the cover 4. 1

The operation of the herein described device is as follows: When the spring l3 overcomes the power element in the spring will move the thrust rod l2 downwardly, pivoting lever 28 in a counterclockwise direction, as seen in Fig. 1. Counterclockwise movement of lever 28 will permit the spring 36 to pivot lever 25 in a clockwise direction about its fulcrum member 23 moving the lever 25 toward the poles of magnet 63 and the contact member 45 toward its cooperative contact member 46. After the lever 25 has been 7 moved'a predetermined distance toward the poles of magnet 53, the attractive force ofthe magnet will become effective and pivot the lever with a quick action moving contact member 45 into engagement with its cooperative contact member 45. Initial engagement of contact member 45 with contact member 45 is made before the stop member ll, carried by lever 25, engages the casing top wall 2, and the positions that the contact member 45, blade and leaf spring 55 will be r/ln upon initial engagement of the contacts are shown in dot-and-dash lines in the enlarged views, Figs. 4 and 5. As the lever 25 continues to pivot in a counterclockwise direction, after initial engagement of contact member 45 with contact member 45, a rolling motion is imparted to the contact member 45 due to the angle ofthe end portion 41 of blade 45 that carries the contact member 45. Simultaneous with the rolling :action the contact member 45 is pulled and slid along the contact surface of contact member 45 to its final position, which position is reached when the stop member 55 engages the casing top wall 2. The sliding action of the contact member' 45 also keeps the contact member engaging surfaces clean. As the contact member 45 is moved from its initial point of engagement with contact member-45 to its final point of engagement therewith, the blade 45 and leaf spring 39 are further tensioned and the tension force urges contact member 45 against contact 45, which tension force remains constant irrespective of the differential setting of the device. The leaf spring rubs against the flexible or spring blade 45 and this action, in addition to the difference in the natural vibratory frequencies of the blade and spring, tends to dampen vibratory. motion of the blade and vibratory motion of the whole switch assembly. Thus the leaf spring 35 dampening vibration of the blade 45 minimizes the bouncing action of the contact member 45 on initial engagement of the contact members. The rolling action of contact member 45 following its initial engagement with contact member 45 provides for engagement of the contact members at successively new contact areas on each of the surfaces during vibration of contact member 45 to avoid fusing of the minute molten pools of contact metal which are present at each end of the electric arc, even though bouncing or vibration of the contact member 45 is minimized by the leaf spring 35.

When the force exerted by the power element ll builds up and becomes equal to the force exerted by the spring I! and the holding force of magnet 53, the power element will move the thrust rod l2 upwardly which will pivot lever 25 in a clockwise direction, as seen in Fig. 1, and will pivot lever 25 in a counterclockwise direction. Counterclockwise movement of lever 25 will move the contact member 45 out of engagement with contact member 45 thus opening the circuit. Movement of the lever 25 by the power element I 5 is quick or with a snap action, and therefore the contact members 45, 45 are quickly parted to reduce sparking of the contact members on parting of the same. It will be seen that parting of the contact members with a quick movement is aided by the tension forces of the blade 45 and spring 35 for these forces are acting to part the contact members when the switch is in closed circuit position. In the event that the contact members 45, 45 do stick, downward movement of lever 25 will cause a prying or bending action between the contact members which for sticking will disengage contact member 45 from contact member 45, and in the event ofseverestickingthebendingorpryingaction.

hers is minimized by providing for the contact members to engage at different points on each of their contact surfaces as the movable contact member bounces or vibrates following initial engagement of the contact members. Furthermore we have provided a switch in which fusing and accompanying sticking of the contact members is very unlikely to occur, but one having provisions to part the contacts in the event that sticking does take place. Also, we have provided a control device having a-new and improved adjustment means for adjusting the position of a magnet relative to its armature. In addition, we have provided a switch of a character such as to prolong the time period of usefulness of the contact members and one which is efficient and reliable in operation.

What we claim and desire to secure by Letters Patent of the United States is:

1. In an apparatus of the character described.

a fixed contact member having a flat contact surface, a second contact member having a convex contact surface engageable with said fiat surface, a spring blade carrying at one end said second contact member, a lever movable relative to said first contact member and having an offset portion, means securing the other end of said spring to said onset portion, said offset portion being so positioned relative to said first contact member that as said lever is moved in one drection to engage said second contact member with said first contact member the offset portion will move away from said first contact member so that upon engagement of said contact members said convex surface will be drawn slidably over said fiat surface, said blade flexing upon engagement of said surfaces so that said convex surface is rolled on said fiat surface simultaneously with the sliding engagement of said surfaces, and a spring bladesecured to said offset portion and having a free end portion engaging said first-named blade intermediate said offset portion and said second contact member' and tending to urge said contact surfaces into engagement, said blades having diiferent periods of vibration so that upon engagement of said contact surfaces said second blade will frictionally and resiliently dampen vibration of said first blade and said second contact member.

2. In an apparatus of the character described, a fixed contact member having a fiat contact surface, a second contact member having a convex contact surface engageable with said fiat surface, a spring blade carrying at one end said second contact member, a lever movable relative to said first contact member and having an offset portion, means securing the other end of said spring to said offset portion, said ofi'set portion being so positioned relative to said first contact member that as said lever is moved in one direction to engage said second contact member with said first contact member the offset portion will move away from saidfirst contact member .0 that upon engagement of said contact members said convex surface will be drawn slidably over said flat surface, said blade flexing upon engagement of said surfaces so that said convex surface is rolled on said flat surface simultaneously with the sliding engagement of said surfaces, a spring blade secured to said offset portion and having a free end portion engaging said first-named blade intermediate said oifset portion and said second contact member and tending to urge said contact surfaces into engagement, said blades having diflerent periods of vibration so that upon engagement of said contact surfaces said second blade will frictionally and resiliently dampen vibration of said first blade and said second contact' member, and means to limit movement of said second contact member on said fixed contact member.

3. Inan apparatus of the character described, a fixed contact member having a fiat contact surface, a second contact member having a convex contact surface engageable with said fiat surface, a spring blade carryin at one end said second contact member, a lever movable relative to said first contact member and having an oflset portion, means securing the other end of said spring to said oilset portion, said offset portion being so positioned relative to said first contact member that as said lever is moved in one direction to engage said second contact member-with said first contact member the offset portion will move away from said first contact member so that upon engagement of said contact members said convex surface will be drawn slidably over said flat surface, said blade flexing upon engagement of said surfaces so that said convex surface is'rolled'on said fiat surface simultaneously with the sliding engagement of said surfaces, a spring blade secured to said offset portion and having a free end portion engaging said first-named blade intermediate said ofi'set portion and said second contact member and tending to urge said contact surfaces into engagement, said blades having diii'erent periods of vibration so that upon engagement of said contact surfaces said second blade will frictionally and resiliently dampen vibration of said first blade and said second contact member, and means to positively disengage said contact members upon movement of said lever member in a direction opposite to said one direction.

EARNEST J. DILIMAN. JACK E. FLEURY.

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