US1899955A - Thermostat switch - Google Patents

Description

March 7, 1933. E GRANT ET AL 1,899,955

THERMOSTAT SWI TCH Fild May 7, 1930 Fig. 1 is a planview Patented Mar. 7, 1933 l UNITED- STATES PATENT l, OFFICE Y ALBERT E. GRANT, OF YORK, AD vSAI'ITJ'IEB'; W. VANZEB'BEEK, 0F T,

` NEW YORK i THERMOSTAT swrrcn s Apinicatin med nay 7, 1930.' .serial nu. 450.344.

Our invention relates to electric switches.

The object of our invention is to provide an electric switch and thermostat construction in which are embodied automatic means I3; for regulating .the timing of the Jaction .of

thel switch, and manually operated means for regulating the timing action of the switch. Y `l A `further object is to provide a construction in which the contacts are caused to slide in contact with each other to prevent their sticking together at the time of breaking'the circuit. A further object is to provide means by which lthe contacts are held togethenwith increased pressure just prior to the breaking of the circuit.

A` further object lis to provide a switch mechanism which will not strain the thermostat element in the act of operating the switch, and which will permit a wide gap between the contact points to prevent arcmg' when the circuit is broken.

Referring to the drawing which pait of this specification:

ola switch mecha- .nism of the single pole type in which our invention is shown. f

Fig. 2 is a side elevational view of the lconstruction shown in Fig. 1, the base plate bein shown in section.

'g'. 3 is a ragmental view showing the means for holding the thermostat element and manually adjusting the same, the view being taken on line 3, of Fig. 1.` Fig. 4 is a view taken on line 4.-4 of Fig. 1. Fig. 5 is an illustrational view, taken Lon line 5-5 of Fig. 1.

Fig. 6 is a plan view showing a double pole switch and a modified form of thermostat element.

Fig. 7 isa longitudinal sectionlyiew of the lever shown in Fig. 6 on line 7 -7 thereof. Fig. 8 is a cross sectional view of the lever shown in Fig. 7 taken on linev 8-18 thereof. Fig. 9 isa cross sectional view of the lever, taken on line 9`9 of Fig. 7. j 10 indicates a base-plate of insulating material, on which is mounted the switch mechforms a 0 anism. It is provided with a circular hole,

11 in which isaed a. memrplug 12 on' aie top of whichis. carried a small near lts perlphery as shown.

This plug is connected to al crank 14 having an upwardly extending handle 15 1ocated adjacent one edge .ofthe base-plate as illus.-

trated in Fi ures 1, and 6.. f

A iyellock 16 formed substantially as shown, 1s held on the base-plate by a screw A17, which extends thru the base-plate into,

the boss 16 ofthe block to hold it in InovableArelation with the base-plate.

The block 16 is provided with a longitudinally extending V-shaped slot 18 inthe construction shown in Fig. 1, which terminates in a slot having parallel walls, and one end of a bi-metallic thermostat element 2() is supported between said walls' by a cross-pin 19 pin` ,13 located 1n such a manner as will permit the free end I of the thermostat to swing upwardly there- Ion as illustrated in dotted lines in Fig. 3.

21 indicates a terminal for a plugconnec.

tion, which is carried by a vstrip o conductionf metal 2 2 held tothe base-plate by ,a screw23. The strip 23 is bent upwardl d at` one end to form a bracket 24 on whic is mounted a contact point 25. 26 indicates a terminal which is carried by a strip 27 which is secured to the base-plate by screws 28.

29 indicates a screw which extends thru a hole formed in the lever 30 near one end thereof, the hole being countersunk' on both sides, and of larger diameter than the screw, to permit the lever to tilt a limited distance on the spherical surface 31 of a washer 32 thru which the screw extends into a thimble 33 Xed inthe base-plate.

The end of the lever adjacent its support may be formed on its upper side, with curved surfaces 34 as illustrated in'Fig. 5 or Fig. 8

(shown on an enlarged scale).

AIn Figs. 1 and 2, we have illustrated the. bar 30 as a cast metal bar, and in Figs. 6, 7,

and 9, as a sheet metal stamping. It may be made in any way desired but is lighter in 4weight when made of stamped metal and helical spring 36 is connected to the lever adjacent the contact point 35 and its opposite @lend is connected to the free end of the thermostat 20 by a screw 37 which extends thru a 5 loop formed in the end of the thermostat and carries a clip I38 to which the end of the spring is attached as illustrated. I'n the construction shown in Fig. 7, a lip 39y is formed.

integral with the lever in the stamping operation, and a loop is formed in the end of the of the surfaces 34 as indicated in Fig. 5.

In Fig.- 6, another circuit may be closed iminediately after the circuit thru contact points 25 and 35 is broken, by the contact points 40 and 41 beingbrought together, as

will be readily understood.

The bracket 42 serves as a stop for the movement of the lever in Fig. 1, and also carries the contact point 40 when constructed as shown in Fig. 6. 43 and 44 indicate electrical/resistance heaters.

4W and carr gether.

The operation of the device is substantially the same in both of the constructions shown, the snap action atY the break kof the circuit being obtained in both movements of the lever 30.

Assuming the terminals 21 andv 26- to be coupled in circuit with a source `the currentwill .How thru the heater 43, strip 23', contacts 25 and 35 to the lever 30 and strip 27 to the terminal 26, thus energizing the heater 43 which is located adjacent the thermostat 26. a

The heat generated by the heater 43 causes the thermostat to bendin the usual manner, th lower end of the screw 37 against t e adjacent surface 34 of the lever 30, causing a retardation of the movement of the thermostat in its travel, and holding the contact oints 25 and 35 more rml toow if the thermostat is hel rigidly in the block l16 in such a manner as to prevent the free end from rising, the lever 30 will be forced to tilt on its fulcrum at. 3,1, and the contact point 35 will be forced to slide upwardl in contact with the contact point 25 in ba s iding action, which will prevent any stickin between said points, and when the screw as passed over the surface 34, the sprin 36 will act to instantly break the circuit t ru the heater 43 and closethe circuit thrudthe heater 44 as will be readilyvunde'rstoo lNow 4we will assume that both the lever 30 and thermostat 20 are free to tilt; the lever 6,0 will not tilt so far as before, but will tilt far enough to cause the contact to Vslide a limited distance, and thus prevent sticking, as before explained.

It is obvious thatathe lever 30 may beso mounted that it will not tilt, andthe switch.

0f supplie' .by moving the handle 15 and crank 14, thus causing the pin 13 to swing the block to the desired position and causing the thermof stats free end to normally rest nearer to the lever, or further therefrom.

A further means for timing the action is by the use of the block 16, which absorbs heat from the thermostat fora period of time, thus causing a delay in the action of the switch. This block may be made in different sizes, depending on the service required. For illustration; if the heater and switch mechanism is to be used in a coffee percolator, the switch mechanism may be set to operate in l5 or 2O nminutes .before the thermostat will be heated to a suilicient degree to break thecircyuit, as will be readily understood.

lt is obvious that the heater may be left out of the circuitand an electric motor or other device substituted -thereforeand located at a distancefrom the switch, and the switch energized from another source of heat, located adjacent said thermostat.

` There is practically no mechanical strain on the thermostat in operating the lever 30, due to the alignment of the spring and thermostat being substantially the same, and therefore the strain is not at an angle suii'icientto bend the thermostat or retard its movement.

The mechanism is simple and dependable and low in cost of construction.

Having thus described our invention, we

1. A .switch of the character described, comprising a base-plate, a thermostat having a normally straight portion one end of which is free to move, a lever havingits fulcrum near one en'd thereof and carrying a. contactpoint at its opposite-end, aspring connected at one end with the free end of the thermostat, and its nother'end connected with the` opposite end of the lever adjacent said contact-point; the ends of said lever being movable laterally. to break ythe circuit and said thermostat being movable into engagement with the lever to move the same upwardly whereby one contact .slides relative to the other contact to7 prevent the contact points from sticking together. v

2.v A switch comprising a base-plate, a

Acontact-point supported thereon, a lever mounted on the base-plate in tiltable relation thereto having its fulcr'um near one end thereof and carrying a contact-pointat its yopposite end movable in sliding relation t0 said contact-point mounted on the base-plate,

and a thermostat adapted to contact an end of said lever and tilt the same to cause a sliding movement between the contact-points in the act of breaking the circuit.

3. A switch comprising a base-plate, a lever mounted thereon having a contact point adjacent one end thereof, a, contact-point supported by said base-plate, a thermostat having means adapted to Contact with the short end of said lever and cause said contactpoints to press together with increasing pressjllre just prior to breaking the circuit theret ru.

4. As stated in claim 3; said lever being so mounted as to permit movement laterally and upwardly.

5. A switch comprising a base-plate, a lever mounted thereon having a contact-point adjacent one end thereof and having its opposite end formed with a curved surface, a contact-point supported by said base-plate, a thermostat having means carried by the free end thereof for contacting the c'urved surface of said lever in the act of breaking the circuit thru said contact points.

6. As stated in claim 1; said spring and thermostat extending in parallel relation to prevent excessive strain on said thermostat.

7. A switch comprising a base-plate, a contact-point supported thereon, a. lever mounted on the base-plate in tiltable relation thereto having its fulcrum near one end thereof and carrying a contact-point at its opposite end movable in sliding relation to said contactpoint mounted on the base-plate, a thermostat adapted to Contact an end of said level` and tilt the same to cause a sliding movement between the Contact points in the act of breaking the circuit, and a spring connected with the lever adjacent the contact-point thereon and with the thermostat adjacent its free end, said spring and thermostat extending substantially parallel to each other.

8. As stated in claim 5; a metal block conneoted in heat conducting relation with said thermostat7 and means for adjusting the position of said block to govern the timing action of the switch.

In testimony whereof I have affixed my signature. v

ALBERT E. GRANT;

In testimony whereofI have aHiXed my signature.

SAMUEL W. VANDERBEEK.

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