US2241748A - Stack switch - Google Patents

Description

v `May 13 1941 B. E. sHAw 2,241,748

STACK SWITCH Filed Sept. 11, 1939 2 Sheets-Sheet 1 I III Inl. Il'

B. E. SHAW STACK SWITCH May'l, 1941.

Filed Sept. ll, 1939 2 Sheets-Sheet 2 Patented May 13, 1941 aurais s'rAcx swrrcn Burton E. Shaw, Bristol, Ind., assignor to Penn Electric Switch Co., Goshen. Ind., a corporation of Iowa Application September 11, 1939, Serial No. 294,408

(CL 20o-138) 6Claims.

An object of my present invention is to provide'a stack switch including a switch structure and a relay, together with a transformer for various circuits of the stack switch, the parts being of simple construction and of such design that the switch can be made comparatively small and inexpensive from a. manufacturing standpoint.

A further object is to provide a stack switch having improved features of construction whereby better operation characteristics of the stack switch are obtained at less power consumption than in standard stack switches as found on the present-day market.

Another object is to provide a stack switch which includes a switching mechanism formed of a buckled leaf spring having an extension that contacts with the periphery of a notched disc which is controlled in accordance with temperature changes in the stack, the arrangement being such that very little power is needed to operate the switch from one position to the other, so that the motion of the temperaure responsive element may be substantially magnified and yet snap action is secured to insure quick make and break, and eliminate the possibility of the contacts being jarred open by operation of the relay in the stack switch.

Still another object is to provide a relay which can be made suiliciently powerful, yet rel-atively small, to minimize current consumption and to minimize jarring of the stack switch as a result of operation of the relay from one position to the other.

More particularly, it is my object to provide a relay which has a solid core and a shading coil serving in addition to its shading coil capacity as a spacer between the relay and a panel on which the relay is mounted. n

Among other objects of the invention, I provide a panel for the stack switch mechanism and the relay which is supported in position by a transformer supporting bracket and a pair of screws which retain the bracket in supported position, the panel and the bracket cooperating with each other and with the casing for the stack switch in such manner that the parts may be placed in their proper relative positions and then all of them held there by the mere insertion of two screws.

A further object is to provide a relay which has a hard silicon steel core and therefore loses all residual magnetism when current is discontinued, thus making it possible. by using hard-silicon `for a magnetic frame of the relay and an arma- -l ture thereof, to permit the armature to touch the frame in closed position so that there is a maximum of holding power to guard against undesired opening of the relay as a result of voltage drop.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly, I have illustrated a preferred and desirable embodiment of the invention in the accompanying drawings, in which:

Figure l is a front elevation of a stack switch embodying my invention, with the cover removed to show interior construction details;

Figure 2 is an enlarged sectional view on the line 2 2 of Figure 1 showing a switch mechanism actuated by a stack temperature responsive element. The switch is in closed position;

Fig. 3 is a view similar to Fis. 2 showing the switch in open position;

Figure 4 is an enlarged sectional view on the line 4-4 of Figure 1 showing relay mechanism of my stack switch. 'I'he relay is in open circuit position.

Figure 5 is a similar sectional view showing the relay in closed position;

Figure 6 is a sectional view on the line 6-6 of Figure 5;

Figure 7 is a perspective view of a. combined spacer and shading coil, and

Figures 8 and 9 are sectional views on the lines 8--8 and 9-9 of Figure 4.

In the accompanying drawings, I have used the reference numeral I0 to indicate generally a casing. A tubular support I2 extends from the casing I0. A coiled bimetallic element I3 has one end connected to the tube I2 at I4 and its other end secured to an actuating rod I5. The bimetal element I3 is adapted tobe inserted in the stack of an oil or gas burning furnace so as to respond to the temperature therein.

Within the casing I0, a disc I6 having a notched periphery is mounted on the rod I5. A panel i1 is supported in the casingl and has a notch I8 through which a portion of the disc I6 extends to cooperate with an extension I9 0f a contact spring 20.

The contact spring is mounted in buckled position between upper and lower arms 2I and 22 of va bracket 23. The spring 20 is buckled suiliciently to normally retain a contact 24 carried thereby against a stop screw 25. Opposite the stop screw 25 is a cooperating stationary contact 26 carried by a bracket 21.

Therextension I9 is U shaped, as shown in Figures 2 and 3, having a terminal end 28 adapted to contact with the periphery ofthe notched disc I6. The terminal end 28 may be adjusted toward or away from the disc for proper operation of the stack switch contacts 2 4--23 by means of an adjusting screw 29. The U shaped extension I9 has an inherent tendency to contract in width and may be expanded or permitted to contract by rotating the adjusting screw 29 in the proper direction. As shown by dotted lines in Figure 2, as the disc I6 continues to rotate counterclockwise it will spring the extension I9 and the spring 29 and permit the notches of the disc to slip past the extension i9 without breaking the circuit across the contacts 24-26. Immediately upon reverse rotation of the disc, the switch will be thrown to the other position, as shown by solid lines in Figure 3. Upon continued rotation in a clockwise direction, the notched disc`will slip past the extension I9, keeping the contacts` open as illustrated by dotted lines.

The panel I1 at its upper endy has a pair of projections 39 extending through perforations 3I in the casing I0 (see Figures liand 2). This positions the upper end of the panel, while the lower end thereof is positioned by resting on a seat 32 of a bracket 33. The back end of the bracket .has a pair o f projections 34 entering openings 35 of the back of the casing I0, as shown in Figure 3. The bracket 33 also has a pair of.

threaded ears 36'receiving screws 31 extended through the walls of the casing I0.`

The bracket 33 has a pair of downwardly extending portions 39 (see Figure l) terminating in perforated ears to receive screws 39 for supporting a transformer T. 'I'he bracket 33 accordingly serves both thepurpose of a support for the transformer and a means cooperating with the casing I0 and the panel I1 to position the panel; the screws 31, when they are inserted in position, eilecting retention of all the parts 33, T and- I1 in their proper relation to the casing I0.

On the panel I1, I provide a safety switch SS, described in my copending' application, Serial No. 294,409 filed September 11, 1939 and which therefore will notl be described further in this application.

VOn the back of the panel I1, I mounta relay consisting of a coil 40, a core 4I, a magnetic .frame member 42 and an armature 43. A nonmagnetic frame member 44 of brass or the like is secured to the core 4I by riveting the core as indicated at 45. 'I'his also retains the magnetic frame member42 on the core.

tongue may-bebent downwardly, as shown by dotted lines in Figure 4, to increase the tension of the spring 49 without the necessity of having to provide an adjusting screw for this purpose.

The frame member 44 has a ilngerlike extension 5I bent to a position above the armature 43 to act as a stop therefor, as shown in Figures 4 and 6.

On the front of the panel I1 are a pair of stationary power contacts 52 and a stationary low voltage contact 53. Cooperating therewith are a pair of movable contacts 54 and a single movable contact 55. The contacts 54 and 55 are carried by contact leaf springs 56 and 51. The spring `51 is secured to the armature 43 under a block of insulation 58, while the spring 53 is riveted to the upper end of the block as at 59. The block 53 is secured to the armature 43 by a pair of rivets 58a.

The leaves 56 and 51 extend through openings 60 and 5I of the panel I1 so as to expose the contacts 54 and 55 on the front thereof where they are readily accessible for inspection and cleaning. The leaves 56 and 51 are substantially straight, thus eliminating the necessity of bending dies for forming them, and the spring 58 is T-shaped, as shown in Figure 6, so as to provide a bridging contact for the contacts 52. The T head arrangement of the spring 53v provides substantially equal contact pressure on both contacts 52 when the relay is in closed circuit position. The contacts 54 being mounted sub- -stantially above the pivot of the armature 43 on the shoulders 48, give a good wipe to these contacts relative to the contacts 52 to keep them clean.

The core 4I is made of hard silicon steel, which requires no machining and `loses all residual magnetism when the coil 40 is de-energized. The frame member 42 and the armature .43 are likewise made of hard silicon steel, to provide for a maximum of loss of residual magnetism. This makes it possible to have the armature contact the frame 42 at the point 80, illustrated in Figure 8, when the relay is ,in closed position. Since contact of the parts gives maximum attraction, this arrangement requires a considerable reductionin line voltage before the relay drops out. Hard silicon steel also has the characteristic of requiring less current for operation, and therefore the coil 49 may be made relatively small.

To minimize eddy currents, a shading coil SC is provided consisting of a piece of copper formed Screws B8 extend through the panel and are threaded into the frame member 42, the leg 3.5

' of the shading coil being notched at 31 to proout departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim as my invention and desire to secure by Letters Patent of the United States is: 1. In a stack switch, a casing, a notched disc in said casing. a switch coacting therewith, temperature responsive means for rotating said disc, said switch comprising a buckled leaf, a contact carried thereby, a stationary contact for engagement therewith, a. projection from said buckled leaf, said projection being U-shaped, an adjusting screw carried thereby to open or close the U, the free end of said projection engaging the periphery of said notched disc to be swung in one direction or the other by rotation of the disc in opposite directions and consequent movement of said buckled leaf with snap action from one circuit controlling position tothe other.

2. In a stack switch, a notched disc, a switch coacting therewith, temperature responsive means for rotating said disc, said switch comprising a buckled spring leaf, a contact carried thereby, a stationary contact for engagement therewith, a projection from the side of said buckled leaf, a disc engaging element on the free end of said projection and engaging the periphery of said notched disc to be swung in one direction or the other by rotation of the disc in opposite directions and consequent movement of said projection and thereby said buckled leaf with snap action from one circuit controlling position to the other.

3. In'a stack switch, a notched disc, temperature responsive means for rotating said disc, a switch comprising a buckled leaf, a contact carried thereby, a stationary contact for engagement therewith and a projection from said buckled leaf, said projection being U shaped, an adjusting screw carried thereby to open or close the U, the free end of said projection engaging the periphery of said notched disc to be swung in one direction or the other by rotation of the disc in opposite directions.

4. In a stack switch, a notched disc, temperature responsive means for rotating said disc, a switch comprising a buckled leaf, coacting contacts controlled by swinging thereof in opposite directions, a projection from one side of said buckled leaf, a U-shaped element having one arm connected to said projection and its other arm engaging the periphery of said notched disc to be swung by rotation of the disc in opposite directions and thereby effect movement of said buckled leaf with snap action from a position with said contacts open to one with them closed or vice versa.

5. In a stack switch, temperature responsive means, a disc rotatable thereby, a switch comprising a buckled leaf, a contact carried thereby, a stationary contact for engagement with said contact of said leaf, a return bent projection from said buckled leaf, an adjustingA screw for adjusting the distance between the sides of said return bent projection, the free end of said projection engaging the periphery of said notched disc to be swimg on one direction or the other by rotation of the disc inA opposite directions, and subsequent movement of said buckled leaf with snap action from one circuit controlling position to the other.

6. In a switch structure, a notched disc, temperature responsive means for rotating said disc, a switch comprising a buckled spring leaf, coacting contacts controlled by buckling thereof in opposite directions. and a U-shaped element having one ann secured to said buckled leaf and its other arm engaging the periphery of said notched disc to be swung by rotation of the disc in opposite directions and effect movement of said buckled leaf with snap action.

BURTON E. SHAW.

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