US2235338A - Stack switch - Google Patents

Description

B. E. SHAW STA-CK SWITCH March 18, 1941.

Filed NOV. 15, 1959 INVENT OR. fia/rzo/z. flfzaza BY %w an? ATTORNEYS Patented Mar. 18, 1941 STACK SWITCH PATENT OFFICE Burton E. Shaw, Bristol, Ind., assignor to Penn Electric Switch 00., Goshen, 1:16., a corporation of Iowa Application November 15, 1939, Serial No. 304,558

8 Claims.

My present invention relates to a stack switch having a novel snap switch unit and temperature responsive mechanism for actuating the same.

One object of the invention is to provide animprovement in stack switch operation over the types of actuating devices now in general use for operating the switch unit of the stack switch from a coiled bi-metal element or other temperature responsive device.

Another object is to provide operating mechanism for the switch unit of the stack switch which minimizes the possibility of jarring the stack switch contacts after they have been moved to either closed or opened position and the temperature continues to change.

In this connection it is well known in the art that a desirable characteristic of a stack switch is that the switch will be moved from one position" to the other substantially immediately upon a change of temperature in either direction as distinguished from most thermostats which close or open at a predetermined temperature.

Much difficulty has been experienced in providing an efficient slip connection between the temperature responsive element and the switch unit to permit continued movement of the temperature responsive element after the switch has been opened or closed without further affecting the position of the switch until such time as the temperature reverses.

Friction connections have been used but the degree of friction is uncontrollable.

Another method has been used in which a disc u with a notched periphery has a leaf spring engaging the notches. This has the disadvantage of considerable movement of the leaf spring as the notched disc continues to rotate after the switch has been opened or closed,

To overcome the difliculties experienced with friction and notched disc connections, I provide a modification of the notched disc connection in which the disc instead of having notches in the periphery has them in one face thereof, a novel 45 actuator for the switch being rotatable relative to the disc and including a leaf spring member provided with ball seats in which balls are seated and pressed thereby into engagement with the notches in the face oi the disc.

so The foregoing, other and further objects of the invention will be. apparent to those skilled in the art to which this invention appertains, by reference to the following description, accompanying v drawing and appended claims. One embodiment 55 of the invention is illustrated in the accompanying drawing wherein the views thereof may be described as follows:

Figure 1 is a front elevation of a stack switch embodying my invention, the cover for the casing thereof being removed.

Figure 2 is an enlarged sectional view on the line 2-2 of Figure 1 showing the stack switch in open position.

Figure 3 is a similar-view of a portion of Figure 2 showing the stack switch in closed position. 10

Figure 4 is a perspective view of the snap switch unit and its actuator which particularly form the parts of the present invention; and

Figure 5 is a sectional view on the line 5-5 of Figure 2. 15

In the accompanying drawing I have used the reference character Cto indicate generally a casing of a stack switch. Within the casing C a panel I0 is provided below which a transformer I2 is supported for supplying current to the vari- 20 ous circuits passing through the stack switch. The transformer 12 and several other parts (such as relay contacts i3 and I4 and a safety switch I5) form no part of my present invention.

On the panel 10 I mount a snap switch unit 25 S. The snap switch unit S, as shown in Figure 3, comprises a rectangular frame i6 having an open center and between the ends of the frame a buckled leaf spring H.

The leaf spring 11 may be curved in either direction, as shown in Figures 2 and 3. When the curvature is downwardly with relation to the panel l0, contacts [8 and i 9 of the stack switch are open, as in Figure 2. When the curvature is reversed they are closed, as shown in Figure 3.

The contact i8 is carried by the leaf spring ll, while the contact i9 is a stationary contact carried'by a bracket 20. The bracket 20 is secured to the panel [0 by a rivet 2|. As shown in Fig ure 2, the spring I? has an extension 22 with which a circuit wire 23 may be connected. The wire 23 is one terminal of the switch while the bracket 20 or the rivet 2| is the other terminal thereof. The snap switch unit S may be connected in any suitable stack switch circuit such as one of the kind shown in my Patent No. 2,080,580, of May 18, 1937, and forms no part of the present invention.

For actuating the snap switch unit S by reversing its curvature I provide a projection 24 thereso on. An actuator A coacts therewith. The actuator A is rotatable on a sleeve 25 which in turn is secured to a shaft 26 by a set screw 21 (see Figure 5). A disc 28 is rigidly secured to the sleeve 25 for rotation therewith by assembling it against a s5 shoulder 29 thereof and spinning or riveting over an end portion 30 of the sleeve. A second shoulder 3| is provided between which and the disc 22 the actuator A-is mounted for relatively free rotatim. g

The shaft 26 is rotatabiy mounted in a bracket 32 and at its outer end is connected at 33 with a coiled bi-metal element 3|. One end of the coil is thus connected at 22 while the other end is connected at 35 to a stationary point such as the bracket 32.

The actuator A is made of leaf spring material havingapairofarmsli. Eacharmisprovided with a ball seat 31 in which a ball element such as gaballbearingilisseated. Eachannii then curves around the periphery of the disc 28 asattsandhasaterminalend llservingasa stop means to prevent excessive springing "of the 1 arm 3. a

go The disc 28 on one face thereof is provided with an annular ring of relatively closely spaced notches ll. The balls 3| coact therewith under tension of the leaf spring arms 3. Preferably the two balls 28 successively or alternately engage the notches ll as shown by comparison in Figure 2. Y

The actuator A further includes a pair of arms 42 terminating in flanges 23. The flanges l3 straddle the projection 24.

Practical operation In the operation of my stack switch when the bimetal element 3| responds to. a change in temperature in one direction, the disc 28 will rotate counterclockwise to cause the right hand flange 43 in Figure 2 to engage the projection 24 and bow the leaf spring ll downwardly. This separates the contact !8 from the contact l9. Upon further change of the temperature in the same direction 9 the notches II of thediscllwillmtclietpast theballs iswithfirstoneballdroimi gina notch and then the other one.

The alternate dropping of the balls in the notches produces in effect an action equivalent to 45 oneballwithnotcheshalfascloselyspacedas illustrated. Since it is impractical to make the notches closer together than ilhistrated as they could not then have enough depth especiam when the disc is formed as a stamping. It is ohvicus 60 that the alternate en ment of the balls makes it possible to secure a finer division between coaction of the balls with the notches and thereby a smoother action during the further rotation of the disc after the switch has been opened.

Upon a reversal of the tmperature the disc 28 will rotate clockwise as in Figure 3, first moving the left hand flange 13 to engage the proiecticn 24 and this flange finafly urging the projectinnto reverse the curvature of the ii and thereby close the contact l8 against the contact is.

Here again after the contact has been closed, the disc 28 may rotate further in the same direction without affecting the contacts as the notches of the disc will merely slip past Since the springingof theballsandthesprhlg arms 36 is in a direction axially of the disc the slight jarring caused thereby will not be transmitted in the plane of the disc to afiect the closed condition of the contacts.

Thus, I eliminate any possibility of the contacts bouncing against each other but on the other hand make sure that they will remain in good contact with each other during the further movement of the disc 28 in a clockwise direction.

15 The distance between the flanges 43 is for the P p e of giving'a certain lag in operation (usually about 35 to 50 degreesin stacksswltch installations). This, of 'course, is to prevent changing the position of the snap switch unit upon slight changes in temperature as might be 5 caused by increased ordecreased draft through vthefurnaceasdistlnguishedfromcombustion failure or combustion establishment;

The spring arms "are initially of the shape shownby dotted lines in Figure 5;so that when 10 thebalisll areinsertedintheseats fltbeywiil be biased with the desired pressm'e against the notches 4|. The position of the contact I! is so adjusted that the contacts will remain either open as in Figure 2 or closed as in Figure 3, when 15 once moved to either of such positions.

From the foregoing description of the means for providing a stack switch having the desirable characteristics set forth it is apparent that I have devised a practical and emcient construction. My invention is simple and economical and while the fore o n presents one of the preferred forms of embodiment thereof, I desire to reserve the l ght to make whatever changes or modifications may fairly fall within the scope of the ap- 25 pended claims.

whatlclaimasnewanddesiretosecureby letters Patent of the United States is:

1.Inastackswitch,asnapswitch unit and temperature rsponsive mechanmm for operating said 39 snap switch unit. said snap switch lmit comprising arectangularframehavinganopen center,a

buckledleafspringegtendingbetweentlieendsoi? saidframeacontactcarrledbysaidbuckled leaf spring, a stationary contact for coaction 35 therewith, a projection from said buckled leaf spring for reversingthecurvature thereof toeil'ect openingorclosingofsaidcontactswithrespect tceachothensaidtemperatureresponsivemechamsm including a rotatable shaft, a temperature 4 responsive element for rotating said shaft, 8. disc rotatable with said shaft and having a plurality ofclmelysmcednotchesin afacethereuLan actuator rotatable relative to said disc and havhrgapluralitycfballelementsengagedwithsaid 45 nntchestoeflfectrotafionofsaidactuatorwith saidmscasthediscismtamsaldactuatorinchafing a leaf spring biasing said ball elements toengagesaidnotchmofsaiddiscandapairof proiections cyondtheperinheryof saiddisc q amastackswitchaswitchimltandtemperature responsive mechanism for operating said switch :mit, mid temperature responsive mech- 5g amsm mcluding a rotatabie shaft, a temperature it w ar e element for rotating said shaft, 8. disc rotatable with mid shaft and having a plurality of closely spawd notches in a face thereof, an

rotatable relative to said disc and hav- 5 mg a pair of diameia-icaliy opposite ball elements engaged with said notches to effect rotation of said actuator with said disc as-=the disc is rotated, said actuator including a leaf spring memberhiasingsaidballelements'toengagesaid notches of said disc and means for operatively connecting said leaf spring member with said switch unit.

3. In a stack switch, a snap switch unit and a temperature responsive mechanism for operating 70 said snap switch unit, said snap switch unit includin a buckled leaf spring, a contact carried thereby, a stationary contact for coaction with said first mentioned contact, the curvature of said leaf spring being reversible to effect opening or closing of said contacts with respect to each other, said temperature responsive mechanism including a rotatable disc, a temperature responsive element for rotating said disc, said disc having a plurality of closely spaced notches in a face thereof, an actuator rotatable relative to said disc and having a ball engaged with said notches to effect rotation of said actuator with said disc as the disc is rotated, said actuator being operatively connected with said buckled leaf spring to effect such reversal of curvature thereof.

4. In a stack switch, a switch unit and temperature responsive mechanism for operating said switch unit, said temperature responsive mechanism including a rotatable disc, a temperature responsive element for rotating said disc, said disc having a series of notches therein, an actuatcr rotatable relative to said disc and having a pair of diametrically oppositely arranged ball elements engaged with said notches to effect rotation of said actuator with said disc as the disc is rotated, said actuator including means biasing said ball element in a direction axially of said disc to engage said notches and means on said actuator operativcl coacting with said switch unit to operate it from said actuator.

5. In a stack switch, a snap switch unit and temperature responsive mechanism for operating said snap switch unit, said snap switch unit including a buckled leaf spring, a contact carried by said spring, a stationary contact for engagement therewith, said leaf spring at one curvature closing said contacts and at a different curvature opening them, said temperature responsive mechanism including a rotatable shaft,

a temperature responsive element for rotating said shaft, a disc rotatable with said shaft and having a plurality of closely spaced notches in a face thereof, an actuator rotatable relative to said disc having a ball seat, a ball seated therein for contact with the notches of said disc to effect rotation of said actuator with said disc as the disc rotates, means to effect such contact of said ball with said notches, and means of operative coaction between said actuator and said snap switch unit to effect reversal of the curvature of the snap switch by rotation of said actuator from said disc, further rotation of the disc after operation of the snap switch being permitted by the ball and notch connection between said disc and said actuator.

6. In a stack switch, a switch unit and temperature responsive mechanism for operating said switch unit, said temperature responsive mechanism including a rotatable disc, a temperature responsive element for rotating said disc, said disc having a plurality of notches in a face thereof, an actuator rotatable relative to said disc and including a leaf spring member having a ball seat, a ball seated therein for contact un der the bias of said leaf spring with the notches of said disc to efiect rotation of said actuator with said disc as the disc rotates, said leaf spring having a. portion extending beyond said ball seat, curving over the periphery of said disc and terminating on the opposite side thereof, the terminating end serving as a stop portion, and means of coaction between said leaf spring member and said switch unit to effect movement of the switch unit from one position to another by rotation of said actuator from said disc, further rotation of the disc after such movement of the switch unit being permitted by the ball and notch connection between said disc and said actuator.

'7. In a stack switch, a snap switch unit and temperature responsive mechanism for operating said snap switch unit, said snap switch unit comprising a rectangular frame having an open center, a buckled leaf spring extending from end to end thereof, a contact carried by said spring, a stationary contact for engagement therewith, said leaf spring at one curvature closing said contacts and at a different curvature opening them, said temperature responsive mechanism including a rotatable shaft, a temperature responsive element for rotating said shaft, a disc rotatable with said shaft and havin a plurality of notches therein, an actuator rotatable relative to said disc and including a leaf spring member having a plurality of ball seats, balls seated therein for contact under the bias of said leaf spring in a direction normal to the plane of said disc and with said notches to effect rotation of said actuator with said disc as the disc rotates, said leaf spring having portions extending beyond said ball seats and curving over the peripheryof said discs and means of coaction between said leaf spring member and the leaf spring of said snap switch to effect reversal of the curvature of the snap switch by rotation of said actuator from said disc, further rotation of the disc after operation of the snap switch being permitted by the ball and notch connection between said disc and said actuator.

8. In a stack switch, a snap switch unit and temperature responsive mechanism for operating said snap switch unit, said snap switch unit comprising a rectangular frame having an open center, a buckled leaf spring extending from end to end thereof, a contact carried by said spring, a stationary contact for engagement therewith, said leaf spring at one curvature closing said contacts and at a different curvature opening them, said temperature responsive mechanism including a rotatable disc, a temperature responsive element for rotating said disc, said disc having a plurality of notches in a face thereof, an actuator rotatable relative to said disc and including a leaf spring member having a ball seat, a ball seated therein for contact under the bias of said leaf spring with the notches of said disc to cheat rotation of said actuator with said disc as the disc rotates, and means of coaction between said leaf spring member and said switch unit to-efiect movement of the switch unit from one position to another by rotation of said actuator from said disc, further rotation of the disc after such movement of the switch unit being permitted by the ball and notch connection between said disc and said actuator.

BURTON E. SHAW.

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