US2418647A - Thermostatic switch - Google Patents

Description

April 8, 1947.

R. H. JORDAN 2,418,647

THBRMOSTATIC SWITCH Filed May 19, 1944 2 Sheets-Sheet 1 V gm! 3 E J j 5 E as f w 32 g 4! 43 50 2 g: Jyd

40 J I m/(ion 24 29 Inuldfion Z2 2 INV TOR. BY W H. M

A ril 8, 1947. R. a JORDAN 7 'I'HRRQOSTATIG SIITCH rum m 19. 1944 a Sh w-sung;

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j 2 I iliustmte e type at thermostatic switch with which invention will operate The thermostatic invention selstes sponsive devices, 9

temperature controlling e 1 3E3 switch illustrated is similar to that shown in eetueted e switch to en oo posit ol Earnes, Patent O- However, y 0011- An object of my invention is t0 trol invention will operate with other kinds (if molly adjustable eontrolliize device lei? e thermostatic switches static switch whereoyfilie differences t is fi i t ated in F gure 2, I W a thermotuire adjustments be obtained the lei-v static switch having a ease 20, a se member tempeeatore range tee spring member isupporting an insulating Another objeet ALE-7 isf eition is to provide button and two resilient conductin arms 23 teh e temperel, "rolling devise o and 2 13 with contest points F35 and 26 respectively 339,5 Y o g agtjgn. mounted thereon, My controlling device is also lmothey bj i; y ai mmi l "1st1e,te{i in the Figure and is shown generally tempers-tore eomlo ill l 'ee "a The controlling device e ioesteci it most of its component estemelly of the ease as as illusmember m is secured to the base stay suite-isle means, such as by rivets 'eiil eesilieut eonfiuetine' arms elit it nipezstwe eoe switch W w button and are has few met nests, e other at their extreme o l Another object 01 my invention to insuletins lilliieiisl @1081 18 s own is eontrolllng device for a, th tm Se 'e"e1enee character The contact points which is simple in construction to provide l. do not touch unless th y r constrained iecturing economy, by outside influence. e s illustrated in Figure 2,

Other nbjects and a, f ll r Lmder ta the arm is'iconneeteo. an outside conductor invention may be had by referring to the follown the m it is Connected o an o t i e mg description and claims, taken in conjunction with the accompanying drawing n which: he Spring i $1915 V y ow oefflcient Figure i is e side elevetional View e, theretotl'wlmal Expansion, Whemes b member has at very high coefficient of thermal efxpan- 021., Therefore, as the temperature of the sur-= dings of the members Eli and 25 increases, use .1361 '5 tends to expand at a greater rate w membeir ll. The result of this unequal expansion with increasing temperature is that the insulatmg bottom is steadily lowered to- A s the member and the resilient conductarm is disposed to follow therealong. As es the Contact members 25 and 26 are "*orcetl to touch one smother a current passes from we outside conductor 29 through the resilient E l, through the Contact point 25, into the conpoint 2;? and out through the resilient arm to the outside conductor 28. This flow of current is possible as long as the resilient arms 23 through a, bushing and oontects a 11161 H and are close enough together to allow the of the thermostatic switch in which my Contact points and 26 to touch As hereinis used; and b e described the resilient snn 23 is disposed to 8 is a side View of the stem us 11love downwardly with each increase in tempers, invention and illustrates a. extenom v t A? iollowing the insulating button 22 and t 0 side thereof. esuse s disoonnectien between the contact with reference to Figs? 1 of Iii ill points and at some temperature as o'ecle stetie switch in which my controlling slew be used, with the top port of my device shown extending therefrom;

Figure 2 is a cross-sectional View knob of my invention;

li ig'ure proj-e ted. lew'o t. cam bushing used. in my jectecl 011 a list Figuxre 5 is s too View of elevetionel or emlwise my invention;

Figuie 6 is a, side View of es en. elevations enclwise eontrel in my invention;

Figure 7/ is a top View of the stem termined by the position of the resilient arm 24 and its contact point 23.

My invention consists of a device to accurately control the position of the resilient arm 24. My invention is shown generally by the reference figure 3| and consists of a holding jacket or sleeve 32, a slotted cam bushing 33, a stem 34, and a control knob 35. An assembled control device of the type applying to my invention is shown illustrated in Figure 2 with the control knob 35 of the device positioned above an outsidecase plate 38 of the appliance in which it is operating. The stem 34 of my controlling device passes through an opening in the case 38, through the slotted cam bushing 33 which is positioned within the holding sleeve 32, and contacts the resilient arm 24.

The holding sleeve 32 has a circular opening therethrough of appropriate dimensions to accommodate the slotted cam bushing 33, and is secured to the case 23 by any suitable means such as shown by peened tips or rim 31.

The slotted cam bushing 35, which serves as a cam member may be constructed from a fiat piece or material and rolled into shape for insertion in the holding member 32. Figure 4 illustrates the slotted cam bushing 33 in a fiat strip of material prior to being rolled into a cylindrical sleeve and is provided with an opening 38 and a notch 39. As noted, in the illustration, the slot 38 is divided into three sections: A-C, C-B, B-D. The steep part of the slot 33 as shown in Figure 4 from D-B, is to be used for giving the positive off-position movements, the second intermediate part of the slot as shown in Figure 4 from B to C is to be used for regulating the high range of temperature as for example, from cotton to silk when installed in an electric sadiron. A third part of the slot 33 as shown in Figure 4 from C to A is to be used for giving more delicate adjustments of the lower heat range, as for synthetic fibers. The notch 33 is provided for convenience or holding the slotted cam bushing in a predetermined fixed position during assembly. By rolling the strip of material, as shown in Figure 4, into a cylindrical form, a cylinder as illustrated in Figure 5 is pro duced. The cylinder as thus formed and described constitutes the slotted cam bushing 33.

An elevational view of the slotted cam bushing 33 as formed and described is shown in Figure 6.

The stem '34 is composed of a hollow tube 43, an external tab'4l, an adjustment screw 42 and an insulating head 43. The tab 4| may be provided by any convenient means, such as by pinching or squeezing a part of the external circumference of the tube 40 into the tab 4|. The adjustment screw 42 is provided to adjust or initially calibrate the position of the insulating bead 43 within the interior of the stem 34, so that the correct indications are given by the control knob or control dial.

A type of control knob which may be used with my invention is shown illustrated in Figure 3, and in cross-section in Figure 2. An upright fin or rib portion 44 serves to provide a convenient finger tip grip, the circular part 45 is used as a convenient indicator on which to mark various temperature ranges. A set screw and recess is provided, as shown at 41 of Figure 2, for the purpose of attaching the control knob 35 to the stem part 34.

In the thermostatic switch such as illustrated generally by the reference character 20, if the temperature surroundingthe parts 2| and 30 lowers, the button 22 carried on the part 2| is disposed to rise and push the resilient arm 23 and the contact point 25 upward toward the contact point 25 on the arm 24. At any temperature lower than that required to bring the contact points 25 and 26 into contact, an excess pressure is caused by the raising of the insulating button 22.

The excess pressure thus produced is absorbed by bending of the resilient arm 23. Bending of the arm 23 causes no difference in the operation of the thermostatic switch. Conversely, as the temperature surrounding the parts 2| and 33 increases, the insulating button 22 is lowered and the resilient arm 23 follows therealong until contact is broken between the contact points 23 and 26. Therefore, thermostatic control of the temperature surrounding the parts 2| and 33 is maintained by setting the position of the resilient arm 24 and the contact point 26 thereon. From the description given it is seen that a fine adjustment of the temperature desired must of necessity be brought about by a fine adjustment of the resilient arm 24 and the contact point 23. Furthermore, whenever it is desired to assure complete separation of the contact points 28 and 25 to completely remove the appliance from use, it is desirable to permit the resilient arm 24 to raise beyond any possible contact with the resilient arm 23.

For operation, my invention is installed on the thermostatic switch by fastening the holding jacket or sleeve 32 to the case 23 by means of peened tips or rims 31. The slotted cam bushing 33 is inserted within the opening of the holding jacket 32 and securely held therein. I prefer to hold the cam bushing 33 in the holding jacket 32 by a snug, press fit between the parts. However, it is understood that these parts may be welded, brazed, or fastened by other means to hold the cam bushing 33 in the holding jacket 32. The stem part 34 is passed through the interior of the slotted cam bushing 33 with the tab 4| guided into the slot 33 thereof. The controlling knob 35 is secured to the upper end of the cam part 34 by means of the side securing means 41. The insulating bead 43 is inserted in the end of the stem 34 and is held in position by the force exerted on it by the resilient arm 24.

In operation, the tab part 4| is positioned within the slot 33 of the slotted cam bushing 33 such that it will be at the position indicated by the letter A within the slot as shown in Figure 4. When the tab 4| is in the position described, the stem part 34 will be forced against the resilient arm 24 such that both stem 34 and the resilient arm 24 will be positioned downwardly toward the resilient arm 23 a maximum distance. From this position only a slight cooling below the maximum temperature for which the thermostatic switch is designed will cause the insulated button 22 to force the resilient arm 23 and the contact point 25 upward enough to cause contact between the points 25 and 26, and thereby cause reheating of the appliance in which the thermostatic switch is operating. As the tab part 4| is moved circumierentially about the slotted cam bushing 33, that is, as the tab part 4| progresses from the position as indicated by A in Figure 4 and along the slot 33 to the position B as indi cated in the slot 38 on Figure 4, the stem part 34, the controlling knob 35, and the resilient arm 24 with its contact button 26 are disposed to rise away from the resilient arm 23. It is noted, that the slot 38 slopes upwardly at a very slow rate between the reference characters A and C of Figure 4. The angle of-slope between C and B is slightly more than the angle of slope between and C as shown in Figure 4.

Continuation of the slot 38 at the same angle of slope as the part of the slot between the points and B will not ordinarily provide enough rise in the resilient arm 24 to give an off switch movement. Therefore, the steep part of the slot 38 from D to B serves to allow sudden movement of the stem 34 and the control knob 85 under the spring action of the resilient arm 24. The large endward or axial movement described allows the contact point 26 to rise beyond any possible chance of contact with the point 25. Further, the described sudden and pronounced endward or axial movement 01' the control knob 85 gives the user of the appliance complete psychological assurance that the iron or other appliance is disconnected from the supply source.

To make adjustments oi temperature from the lowest temperatures for which the combination of the thermostatic switch controlling device is designed, an operator need merely turn the control knob 35 in such a manner that the tab part 4| is moved along the slotted part 38 of the cam bushing part 33 from the position marked A in Figure 4 through the position marked C and on to the highest temperature position at the point marked B. A slight further movement of the control knob 35 past the position marked B in Figure 4 will bring the tab part 4| into position to be moved freely up the steeply sloping portion of the slot 38. When the tab part 4| is in the oif position described, the spring action of the re silient arm 24 is free to move the stem part 34, and the knob 35 upward with a sudden action for a distance far greater than the total distance moved as a result of the complete rotation of the tab 4| from the position A to B within the slot 38. This sudden action assures the user that the appliance is turned oil, and at the same time allows the resilient arm 24 and its contact button 26 to be completely removed from all possible contact with the contact 25 of the resilient arm 23.

To return the appliance to use, the operator needs merely apply a small amount of twisting action to the control knob 35. This small amount of force will cause the tab to be deflected downwardly along the steep part of the slot 38 and pull the stem part 40 and the control knob 35 therealong. The insulating bead 43 thus forces the resilient arm 24 with its contact point 26 downwardly and causes contact to be made between the contact points 25 and 26.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim as my invention:

1. A thermostatic switch comprising, first and second relatively movable contact parts normally resiliently disposed to separate from each other, temperature responsive means to urge said first contact part against said second contact part, substantially annular cam means supported rel ative to said contact parts, a control stem manually rotatable and axially movable within said cam means to position said second contact part in contactable relation with said first contact '6 part, said cam means having a regulating on portion disposed at a slight angle with reference to a line normal to the longitudinal axis of the stem, said cam means having a relieved of! portion disposed at a steep angle with reference to a line normal to othe axis or the stem, projecting means carried by said stem to cooperate with said cam means, said second contact part urging said stem axially of said cam means and holding said projecting means against said regulating fon portion of the cam means when the stem is rotated to bring the said projecting means in alignment with the regulating on portion whereby turning of the stern regulates the position of the second contact part with respect to the first contact part, said stem thereby holding said second contact part in contactable relation with said first contact part, said second contact part suddenly urging said stem axially of the cam means when the stem is rotated to bring the projecting means in alignment with the relieved "oil" portion of the cam means, said second contact part thereby resiliently moving away from contactable relation with said first contact part.

2. A switch comprising, first and second relatively movable contact parts normally resiliently disposed to separate from each other, support means for supporting said contact parts, cam means carried by said support means and disposed relative to said contact parts, a control stem manually rotatable and movable endwise with reference to said cam means for positioning said second contact part in contactable relation with said first contact part, said cam means having a relieved off portion, projecting means carried by said stem to cooperate with said cam means, said second contact suddenly urging said control stem endwise with reference to said cam means when the control stem is rotated to align the projecting means with the relieved off portion of the cam means, said second contact part thereby resiliently moving away from contactable relation with said first contact part.

3. A switch comprising, a first contact part, a relatively movable second contact part normally resiliently disposed to separate from the first contact part, cam means supported relative to said second contact part, a control stem manually rotatable and movable endwise with respect to said cam means for positioning said second contact part in contactable relation with said first contact part, said cam means having a relieved oil portion, projecting means carried by said stem to cooperate with said cam means, said second contact part suddenly urging said control stem endwise with reference to said cam means when the control stem is rotated to align the projecting means with the relieved off portion of the cam means, said second contact part thereby resiliently moving away from contactable relation with said first contact part.

4. A switch comprising, a first contact part, a relatively movable second contact part normally resiliently disposed to separate from the first contact part, support means for supporting said contact parts, a control stem manually operable and movable endwise with reference to said support means for positioning said second contact part in contactable relation with said first contact part, said support means and said control stem having cam means and cam rider means, said cam means having a relieved oi? portion, suddenly urging the reference to the supaligned said second contact part control stem endwise with port means when the cam rider means is 7 8 fit-"n reiieved 0E portion of the cam means said seesnd csntast part thereby resilientiy mov UNITED STATES FATE E illg away {rem contactable relaticn with said first Number Name Dye (JOHN-8t p 2 185 814 Kuhn Jan 19% RICHARD JORDAN- 5 2,248,666 Fischer July 3,1941 7 1,985,100 Kuhn et a1 Dec. 18, 1934 RFFERENEES CITED 2,158,857 Hall at B1 May 16,1939

The fnliswing references are 01 reccrd in the file at this mtent:

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