US2124999A - Thermostatic control switch - Google Patents

Description

y 1933- A. CHRISTENSEN 2,124,999

THERMOSTATIC CONTROL SWITCH Filed June 24, 1937 h v 2| as 25 5 INVENTOR I7 34 2O 35 I9 26 24 23 3O 45 AXEL CHRISTENSEN ATTORNEYS Patented July 26, 1938 2,124,999-

UNITED STATES PATENT OFFICE THERMOSTATIO CONTRQL SWITCH Axel Christensen, Racine, Wis.

Application June 24, 1937, Serial No. lll,l28

3 (Claims. (ill. 209-137) This invention appertains to control devices, spending parts throughout the several views, the and more particularly to a thermostatically regletter C generally indicates the improved control, ulated control switch capable of general applicawhich embodies a protecting housing or casing tion, and particularly adapted for use in conill. The inner end wall of the casing has conjunction with boilers having oil burners, stolrers, nected therewith a coupling nipple l l. The nip- 5 5 and the like. I v pine l l is in turn secured to the appliance l2, the

One of the primary objects of my invention is temperature of which is to be controlled. to provide a control device of exceptionally sim- The appliance it in the present instance may ple and durable construction, one that will he be considered as a hot water boiler. The horisensitive to temperature changes, and one which zontally extending bore E3 of the nipple ii is it can be easily and quickly associated directly with enlarged at its inner end, as at and this the appliance to be controlled. Another salient portion of the bore receives and supports the object of my invention is to provide an efficient heat responsive means it. mechanism for manually setting the switch to The heat responsive means it includes a tube 5 the temperattu'e that is desired to he maintalnec, it formed from a metal possessing a high coeifiwhereby the device will be capable of controlling cient of expansion and an inner rod ll formed a wide range of temperatures. from a material having a low coefficient of ex- Aiurther important object of my invention is panslon. The rod ii is anchored to a head ill to provide a control device embodying a rner-= rigidly connected to the inner end of the tube,

cury switch pivotally mounted at one end and an and the rod ll extends through the bore and operating lever supporting the other end actuinto the casing ill. atecl from a heat sensitive expansion element i Rigidly secured to-the lower wall of the casing tilting the switch, with means for manually shiftit is a longitudinally extending ii-shaped guide ing the switch and lever bodily toward and away bracket it], the legs ill of which are apertured for from said heat sensitive element, whereby to acslidahly receiving a slide bar ill. The outer end 25 curately control the throwing of the switch when of the slide bar 26 has anchored thereto, by a desired temperature is reached. means of a cross-bar 22, upstanding arms A still further object of my invention is to pro- The arms in turn support pivot pins E l on vide a control device in which wear will he re which is roclrably mounted a supporting plate 39 duced to a rm'nirnum and all lost section elim- Secured to the plate 25 by means of a suit- 30 inated. able clip 26 is a tube or bulb 2'l having a globule With these and other objects in view, the inof mercury 28 or other electric conducting mate vention consists in the novel construction, airial therein. The plate and bulb extend inwardrangement, and formation or" parts, as will be 1y of the pins 2 and hence, in effect, he bulb hereinafter more speciflcally described, claimed, is roclrably mounted at its outer end. 'l'nis end 35 and illustrated in the accompanying drawing, in has anchored therein a pair of spaced contacts which drawing: 29 to "which are connected electric wires til. The Figure 1 'is a longitudinal sectional view electric wires 3% are in turn connected by means through the improved control device. of binding posts to spaced conducting plates 40 Figure 2 is an end elevational view of the eon= 32, to which are secured conductor wires lead- 49 trol device. ing to a source of electrical energy and the device Figure 3 is an enlarged, detail sectional view to be controlled, such as an electric motor of an taken on the line of Figure 1, looking in the oil burner or a coal stoker.

direction of the arrows, illustrating the means Obviously, when the inner end of the bulb 2? for rockably supporting the actuating lever. is in a lowered position, the globule of mercury Figure 4 is an enlarged, fragmentary, detail rides away from the contacts 29 to open a sectional taken substantially on the line circuit. and when the inner end of the bulb is of Figure l, looking in the direction of the in an elevated position, the globule of mercury arrows, illustrating the mounting oi. the mercury will bridge the contacts 253 and close a circuit. 00 switch. The forward end or the slide bar 2i has an- Figure 5 is a fragmentary, top plan view illus chcred the eto the forwardly extending bracket trating the mounting of the actuating lever and 35 on which is rockably'mounted the forward the mercury switch on the slide bar. end of the actuating lever 35. .The lever ex" Referring to the drawing in detail, wherein tends toward the front of casing from its 5 similar reference characters designate corre= pivot pin and terminates in an upwardly curved on or secured to a traveling screw 66.

bearing head 35 on which rests the plate 25 carrying the bulb. The inner end of the actuating lever has formed thereon or secured thereto a depending bearing lip M, which extends below the pivot for the'lever, and this lip is adapted to engage the end of the operating rod ll, which extends into the casing.

Manual means is provided for shifting the slide rod 2!, whereby the position of the lever 36 and the bulb 2? can be varied relative to the operating rod H. The means for manually shifting the position of the slide bar at includes an operating shaft 38. This shaft 38 is rotatably mounted in a suitable bearing ea carried by a removable portion at of the casing. The outer end of the shaft 38 has firmly secured thereto a dial disc ii and an operating knob 32. The dial disc is graduated in the desired manner, and a pointer 63 for cooperating with the dial'disc is carried by the casing.

Secured to the inner end of the operating shaft 38 is an elongated spur gear M, which has constantly meshing therewith a relatively thin spur gear 35. The spur gear $5 is of a greater diameter than the spur gear 58, and is formed This screw 46 is threaded into a guide sleeve =i'l carried by the casing. A suitable bearing knob 48 is carried by the screw 46 and bears against the outer end of the slide rod.. The slide rod is normally held in contact with the bearing knob 48 at all times by a contractile coil spring 59. The

' opposite ends of this spring are suitably anchored to the slide bar 2! and to the bracket i9.

From the description so far, it can be seen that upon the turning of the shaft 38 by the knob 42, the screw 46 will be moved in or out, which will bring about the shifting of the slide bar. This shifting of the slide bar will vary the position of the actuating lever 35 relative to the operating rod ll.

41 use of my improved device, the knob 42 is turned until the dial disc travels to the temperature indicated on the disc, at which the heat is to be maintained. This brings about the initial adjustment of the lever 35. As the appliance l2 increases in temperature, the tube l8 will expand, and the head l8 will gradually draw the rod i'l away from the lip 31.

When a predetermined temperature for which the device is set is reached, the'rod l'l will permit the inner end of the lever 35 to lower, and the bulb 21 will swing down, as shown in Figure 1. The globule of mercury will consequently roll away from the contacts 29. As the temperature lowers, the tube It will contract and the rod l1 araaaaa will be gradually carried inwardly, which will swing up on the inner end of the lever 35, and

when the bulb 2? is again raised to an elevated position, the globule of mercury will flow down the tube-into engagement with the contacts.

The construction of my device is such that the operating lever 35 directly supportsthe mercury switch. This eliminates friction and lost motion, and upon manual adjustment, the lever and switch are synchronously moved toward and away from the operating rod as a unit.

Changes in details may be made without departing from the spirit or the scope of my invention, but what I claim as new is:

1. In a control device of the character described, heat-responsive means movable upon temperature change, a slide bar, a control switch rockably mounted at one end upon the slide bar, an actuating lever movable by said heat responsive member rockably mounted on the slide bar,

and supporting said switch at a point remote. from its pivot point, and means for varying the position of the slide bar.

2. Ina control device of the character described, heat-responsive means movable upon temperature change, a longitudinally movable with the traveling screw, and manual means including a dial and a pointer for rotating the screw.

- 3. In a control device of the character described, heat-responsive means movable upon temperature change, a guide bracket, a slide bar mounted in said bracket and movable longitudinally toward and away from the heat-responsive means, a supporting plate rockably mounted upon the slide bar, a mercury switch on said plate, means detachably securing the switch to the plate, said switch projecting forwardly from the pivot point of the plate, an actuating lever rockably mounted on the inner end of the slide bar including an elongated arm engaging the plate at a point remote from its pivot, and a depending short arm engaging a part of the heat-responsive means, a traveling screw, spring means normally urging the slide bar into engagement with the screw, and manual means for turning the screw.

AXEL CHRISTENSEN.

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