US2398579A - Thermostat - Google Patents

Description

April'ls, 1946. E. K. CLARK Em 2 398 57 THERMOS TAT Filed March 24, 1941 3 Sheets-Sheet 1 WITNESSES: INVENTORS Earl K. Clark and Joseph saw Gm. W

April 16, 1946. CLARK ETAL 2,398,579

THERMOSTAT Filed March 24, 1941 3 Sheets-Sheet 2 34 [d -I-' i2 24 95"" a z ///W7// //W/l .42 12 WITNESSES: INVENTORS Earl if. 6702",? and Jog piz 5. h ajaz'.

April 16, 1946. E. K. CLARK ETAL THERMOSTAT Filed March 24, 1941' s Sheets-Sheet 5 INVENTORS 73 11707! K Clark and WITNESSES:

Joggp/z S l k/ajcilf.

A'i'TOR NEY Patented Apr. 16,1946

Earl k. Clark and Joseph s. Ohio, assignors to Westing Wojcik, Mansfield, house Electric Corpllaiion, East Pittsburgh, Pa., a corporation of a Application March 24, 1941, sci-n1 a... 384,918

2 Claims.

sadirons and, more of the operating tem- Our invention relates to particularly, to the control peratures thereof.

An object of our invention is to provide an electric iron having a thermostat emaciated therewith for regulating the temperature output of the sole plate and having a control knob located in the handle at the point of maximum ease and quickness of operation by the operator's hand during the normal operation of the iron.

A further object of our invention is to provide an iron having a thermostatic device therein for regulating the operation thereof, said thermostat being controlled by an adjusting member which extends forwardly and upwardly so as to be inclined to the sole plate of the iron.

Another object of our invention is to provide a thermostat for an iron structure embodying a bimetallic element which may be mounted substantially parallel to the sole plate and which has an adjusting member extendin forwardly and upwardly so as to be inclined to the plane of the bimetallic element and the sole plate.

Still another object of our invention-is to provide a thermostat for a bimetallic element fulcrumly retained by means tion is adapted to retain the movable end of the element in an open position.

an iron which embodies screw with an enlarged diameter friction and stop member which is engaged by a resilient member for frictionally retarding the movement of the adjusting screw throughout a portion of its rotative movements and which is engaged by the stop member at each limit in operation of said screw for limiting the rotative movements thereof.

Other objects of our invention will either be pointed out specifically in the course of the following description of a device embodying our invention, or will be apparent from such description. l l

In the accompanying drawings:

Figure 1 is a side elevational view of an iron embodying our invention illustrating the ease with which the thermostat may be regulated;

Fig. 2 is a. longitudinal sectional view of the device shown in Fig. 1;

Still a further object of our invention is to provide a thermostat for an iron having a base or supporting structure which fulcrumly or rockably receives a bimetallic element and which receives an adjusting member inclined to the plane of the bimetallic element, which, in turn, actuates a member for changing the curvature of the bimetallic element. by rotating such element abo ut its fulcrum.

Still another object of our invention is to provide an efiicient, rugged, inexpensive, easily manipulated and manufacturahle iron thermostat which may be used as a switch without the inclusion of any additional switching means.

A further object of our invention is to provide an iron handle having upper and lower longitudinal sections joined by two vertical end sections, with a recess in the inner portion of the front end section for receiving a thermostat control knob whereby the control knob blends into the handle and is positioned at the natural finger tip of an operator.

Yet another object of our invention is to provide a thermostat having a rotatable adjusting Fig. 3 is a view similar to Fig. 2 illustrating the preferred form of a thermostat associated with the iron;

Fig. 4 is an enlarged top plan view of the thermostat embodying our invention;

Fig. 5 is a side elevational view of the thermostat shown in Fig. 4 with the contactsin a closed or engaged position;

Fig. 6 is a view similar to Fig. 5 with the adjusting member retaining the thermostat in its open or contact disengaged position;

Fig. '7 is an end view of the device shown in Figs.,4 to 6, inclusive;

Fig. 8 is an enlarged fragmentary sectional view taken along the line VIII-WI]: of Fig. 7;

Figs. 9 and 10 are top and side elevational views, respectively, of the bimetallic element and adjusting member attached thereto;

Fig. 11 is an enlarged fragmentary sectional view taken along the line XI-XI of Fig. 8; and

Fig. 12 is a sectional view taken along the line XII-ml; of Fig. 5.

Referring in particular to Figs. 1 and 2 of the accompanying drawings, in which like reference characters indicate like parts in the several figures, we show an iron structure I 0 having a workmg portion or sole plate l2, a heating element ll for supplying heat thereto, a handle 16 for op erating the iron, a regulating device or thermostatic structure I8 embodying an adjusting member 20 which extends forwardly andupwardly so as to be inclined to the sole plate l2, and a control knob 22 positioned within the handle 15 at the point of maximum ease and quickness of operationby the hand of an operator during the normal operation of the iron.

The iron structure in embodies a sole plate 12,

a heating element l4, preferably of the sheathed type and cast therein, and a handle structure l8. The handle structure [6 comprises a front depending or upstanding portion 24, a rear depending or upstanding portion 25, a skirt portion 21 joining the lower ends of said portions and extending over the sole plate l2, and an upper grip portion 29 connecting the depending portions, which is slightly inclined to receive an operator's hand with the maximum of ease during the normal operation of the iron. The front depending portion 24 is hollow for receiving,

among other things, the adjusting member 20 of the thermostat l8, as hereinafter described. In

addition, a notch or opening 25 is located within the inner surface of the depending portion 24 of handle ii for receiving the control knob 22 for a purpose to be hereinafter described. The general construction of the handle and iron is more fully described and claimed in Patent No. 2,333,521, of E.K. Clark and J. R. Heilman,

- granted .November 2, 1943, and assigned to the ,signee of this application.

The thermostat i9 is, in this instance, mounted at an angle to the sole plate l2, whereby the adjusting member 29 therefor is inclined to the plane of such sole plate. The adjusting member 29 is thus adapted to extend forwardly and upwardly with respect to the sole plate l2 and the knob during the normal operations of the iron.

It will be seen that one reason for these advantages is that the plane of rotation of the knob 20 is substantially in line with the normal line of the operators thumb when normally grasping the grip portion 25.

Our structure, therefore, not only increases the ease of manipulation of the knob but also reduces the muscular efforts of the operator since no shift of the comfortable grip is required. Further, since no delays are necessary in making thermostat adjustments, the total time of ironing toextend into the depending portion 24 of the handle 16. The upper end of the adjusting member 20 is journaled within a suitable bracket 32 attached to the handle It by, say, a suitable screw 34. If desired, a flexible union 2! may be positioned within and along the axis of adjusting screw 20 so as to prevent any binding action between said screw 20 and the supporting structure 28'. A knurled portion 23 is formed within the upper part of said screw 20 for slidably receiving the control knob 22, as hereinafter described.

The controlknob 22 is positioned upon the knurled portion of the adjusting member 20 which prevents any relative rotative movement therebetween whereby said knob can rotate the adjusting member 29 in response to the rotated movements thereof. However, the cooperating mit said member 20 to slide longitudinally with respect to the knob 22 as the knob 22 rotates I the member 20, it being understood that said adjusting member 20 moves along its longitudinal axis when rotated so as to vary the operations of the thermostat I8. The control knob 29 exknurled portions of member 20 and knob 22 pertural arrangement set forth, the knob 20 is located at the point of maximum ease and quickness of operation of the operators hand. As clearly shown in Fig. 1, the thumb (or, if desired, the index finger) of the operator, without requiring any shifting of the operators normal, comfortable grip on the handle, naturally and a batch of goods may be reduced.

Referring in particular to Figs. 3 to 12, inclusive, we show apreferred form of a thermostat for operation in an iron in keeping with the teachings hereinabove disclosed. Said preferred thermostat 36 embodies a base 3 8, a bimetallic element 40, and an adjusting member 42 inclined to the plane of the bimetallic element.

The base or supporting structure 38 comprises, in this instance, an elongated irregularly formed strip of metal which insulatedly support stationary contacts 44, fulcrumly retains a portion of the bimetallic element 40, and threadedly supports the adjusting member 42. Said base or support 38 embodies a main fiat central portion 45 with a downward and outwardly extending end portion 46 at one end thereof and an upwardly substantially parallel flat portion 48 at the other end thereof, joined by an inclined portion 41. A substantially rectangularly-shaped aperture 50 is formed within the end portion 46 and the main portion 45 of the base 38 for receiving one end of the bimetallic element 40, as hereinafter described. A centrally located upwardl extending ear 62 on end portion 45 extends into the aperture 59 for fulcrumly supporting the end of the bimetallic, element, as hereinafter described. In addition, an internally threaded sleeve 49 is rigidly attached to the inclined portion 41 of the base 38 intermediate the main portion 45 and the upper portion 48 so as to be inclined to the plane of the main portion. Said internally threaded member 49 receives the adjusting member 42, as hereinafter described.

The bimetallic element 40 comprises, in this instance, an elongated inherently snap-acting member having end portions 52 and 53 joined by a central strip 54 and to exterior strips 55. The end portion 52 has a centrally located notch 5| extending inwardly from th edge thereof. The exterior strips 55 are corrugated at substantially their midpoints to effectively reduce their length to make the bimetallic element 40 inherently snap-acting in keeping with the teachings of P. R. Lee, Patent No. 2,259,312, issued October 14, 1941, andassigned to the assignee of this application.

A mounting rivet 56 is rigidly attached to the mid-point of the central strip 54 and is rigidly attached to the main portion 45 of the base 38 for rigidly attaching the central strip 54 of the bimetallic element 49 to the base 38, and to maintain the element substantially parallel to said main portion. A fulcruming plate 58 is rigidly attached to the end portion 52 of the bimetallic element 48 by suitable rivets 59 (see Figs. 9 and 10). The plate 58 extends outwardly from the element 48 along the longitudinal axis thereof and has rigidly attached, preferably by rivet 58, t its upper surface a flanged bracket or finger-like member 68 which extends upwardly and back wardly over the element 48. An outwardly extending finger 6l integral with the upper portion of the bracket 68 is offset therefrom to cooperate with the adjusting member 42, as hereinafter described.

When the bimetallic element 48 is rigidly at tached to the supporting structure by means of rivet 56, the fulcrumin plate 58, attached to the end portion 52, extends outwardly through the aperture 58 in the base 38, permitting the fulcruming plate 58 to rest against the centrally located upwardly extending semi-circular ear 62. The fulcruming plate 58 is thus retained by means of substantially a point contact (see Figs, 8 and 11) due to the angular relationship between said plate and ear. Inasmuch as the end portion 52 of bimetallic element 48 has an inwardly extending notch cut therein, it follows that the ear 62 engages the fulcruming plate 58 without engaging the bimetallic element 48. However, the cooperation between the ear 62 and fulcruming plate 58 is on a line passing alon the end of the element 48. The element 48 is thus fulcrumly retained by the supporting structure or base 38 so as to be rotatable about an edge, thereof. With the element 48 and plate 58 mounted upon the base 38 in such a manner it follows that the bracket 68, attached to the plate 58, extends above the base 38 for cooperating with the adjusting screw 42, as hereinafter described.

A resilient finger-like member 14 is rigidly attached to the main portion 45 of base 38 by means of a rivet 15. This resilient member 14 extends over the fulcruming plat 58 engaging the bracket 68 and fulcruming plate 58 so as to bias the fulcruming plate 58 into engagement with the ear 62 in the depending portion 46 of base 38. The resilient member 14 thus keeps the fulcruming plate 58 in contact with the ear 62 of base 38 at all times.

An irregularly shaped calibrating arm 88 is rotatably attached to the bracket 68 in juxtaposition therewith by means of a suitable rivet 89. The calibrating arm 88 has an outwardly extendin portion 83 substantially circular in shape which is adapted to cooperate with the adjust ing member 42. The diameter of the circular portion 83 is substantially equal to the length of an undercut portion 82 out within the adjusting member, whereby said circular portion 83 is free to fit under and be actuated by the shoulder marking the end of such undercut portion'82 in the adjusting member. The longitudinal movement of adjusting member 42, responsive to its rotation within threaded sleeve 48, are then transmitted to the arm 88 through the circular portion 83.

The arm 88 thus tends to rotate about rivet 89 as an axis when the adjusting screw 42 is rotated. However, since the arm 88 is rigidly attached to the bracket 68 after the thermostat is calibrated, as hereinafter described, it follows that such longitudinal movement of the adjusting member 42 is transmitted to the bracket 68 and fulcruming plate 58. whereby the longitudinal movements of the adjusting member 42 change the angular position of the fulcruming plate 58 and end portion 52 of bimetallic element 48 with respect to the base or supporting structure 38 so as to adjust the operation of the thermostat.

A movable contact structure 64 is insulatedl attached to the second (shown as right-hand end portion 53 of the bi-metallic element 48 by means of a suitable rivet 66. The movable contact structure 64 includes a loosely mounted bridging member 68 having upwardly extending contact portions 18 which are spherical in shape. In addition, the lower head of the rivet 66 is similarly spherical in shape. Specifically, the contact portions 18 of the bridging member 68 and the lower surface of the rivet 66 are positioned one with respect to the other so as to be segments of an identical sphere. This structure thus permits a uniform switching gap A (Fig. 5) at all operating temperatures of the bimetallic element and all angular positions of the contact end portion of the element. The contact portions 18 of the movable bridging member 68 are adapted to cooperate with the stationary contacts 44 which are insulatedly attached to the upper portion 48 of the base 38 in any well known manner. Suitable terminal members are rigidly attached to the stationary contacts to permit such contaots to be connected. in circuit with the iron heating element l4 and a power supply (not shown).

A horizontally-positioned J-shaped resilient member 12 is rigidly attached to the end portion 53 of bimetallic element 48 intermediate the contact portions 18 and the element 48 by means of the rivet 66. The resilient member I2 extends in wardly from the movable contact assembly 64 and curves upwardly inline with the end of the adjusting member 42 so as to contact the end of such adjusting member topermit the adjusting member to independently disengage the cooperating contacts, as is hereinafter described.

A suitable stop structure embodying a depending shaft 16 and an inwardly extending member 18 are rigidly attached to the upper portion 48 of base 38. The inwardly extending portion 18 is located at the lower end of shaft 16 and extends beneath the movable end portion 53 of element 8 s a t a y parallel to the portion 48 of base 38. A suitable stop screw 88 is threadedly eneased into the member 18 and is aligned with the spherical head portion of the rivet 66 so as to determine the contact gap A (Fig. 5) or the space between the rivet 66 and stop screw 88 when the thermostat is in its closed or operating position. It is to be understood that the contacts will, accordingly, have a separation A equal to this gap when the contacts are in their open position, as illustrated in Fig. 6.

The adjusting member 42 is, in this instance, an elongated shaft-like member having a knurled upper portion 43 which receives the control knob 22 and an undercut notch portion 82 intermediate the ends thereof for receiving the bracket 68- and calibrating arm 88.for a purpose hereinafter described. The adjusting member 42 also has a threaded lower portion whichis threadedly engaged within the bushing 49 so as tobe threadedly supported by the base 38 and to be aligned with the J-shaped resilient member 12. In addition, since the bushing is retained at an angle to the main portion 45 of base 38 and to the element 48, the adjusting member 42 is thus retained along an axis inclined to the bimetallic element 48.

When assembling and calibrating the thermostat embodying our invention, the stationary contacts 44 are rigidly and insulatedly attached to the lower surface of the upper end portion 48 of base 88, and the bimetallic element 48 including fulcruming plate 58 and bracket 88 are risidly attached to the main portion 85 of base 88 by means of rivet 58 attached to the central stri The resilient finger I4 is then rigidly attached to the base 88 to bias or retain the fulcruming plate 58 in direct contact'with ear 82 at all times. The stop assembly including shaft 16, bracket 18, and stop screw 88 are likewise rigidly attached to the upper portion of base 88 and the stop screw 88 is adjusted so as to provide the desired contact The adjusting screw member 42 is then run downwardly into the threaded sleeve member 58 until the inner end of the screw engages the J- shaped resilient member 12 so as to force the the position just described is one limit of the adjusting screw, namely; the foff position of the thermostat. The adjusting screw 42 is then rotated back as far asit will so, such movement being limited by the stop lug 84 engaging the resilient stop bracket 88. (See Figs. 4 and 7) This position corresponds to the upper limit or high position of the thermostat.

The thermostat, with a calibrating screw 83 positioned through a threaded aperture 85 in fulcruming plate 58 so as to engage calibrating arm 88, is then placed within a suitable oil bath, the temperature of which corresponds to the upper or high" setting of the thermostat. After the thermostat, including bimetallic element 48, has increased in temperature and has become stable in operation at the high value thereof, the thermostat is removed from the bath. The callbrating screw 83 threaded through fulcruming plate 58, is then run upwardly so as to engage the calibrating arm 88. A continued upward movement of the screw 83 then causes the ful-- cruming plate 58, attached bracket 88, and the end portion 52 of bimetallic element 48 to rotate in a counterclockwise direction about the ear 82 as a fulcrum.

The counterclockwise movement of the end portion 52 of bimetallic element 48 thus causes such element to change its curvature, since the midpoint of the central leg thereof isrigidly attached to the base 38. Upon the continued changing in curvature of element 48 due to the upward movement of calibrating screw 83, said element will snap to its closed or contact engaged position. This action determines the position of the fulcruming plate 58 and end portion 52 of element 48 for the high setting of the thermostat. In addition, the position of bracket 88, with respect to calibrating arm 88 and adjusting screw 42, is thus individuallyobtained for each thermostat.

The bracket 88 and calibrating arm 88 are then spot-welded or rigidly attached together soas to permanently fix this angular position with respect to the adjusting member 42. The thermostat is thus calibrated between its manual openable or contact-disengaged position and its highest operating value, and the calibrating screw 88 may then be removed from the fulcruming plate 58 and used on further thermostatic structures. In addition, the thermostat is then calibrated throughout its entire range, permitting the adjusting screw 42 to selectively adjust the operating arm 88 and bracket 88 so as to change the curvature of bimetallic element 48 and vary the operation thereof.

It is, therefore, obvious that the adjusting member or screw 42, inclined to the plane of the bimetallic element 48, changes the fulcruming posi- 1 tion of the element with respect to the base 38 by means of bracket and arm 88, whereby the operating temperature of the bimetallic element is selectively adjusted by means of said adjusting member. In addition, it is obvious that the adjusting member 42 by engaging the J-shaped resilient member 12 forces the element to a contact disengaged position so as to manually interrupt the circuit through the thermostat.

The thermostat 88 is rigidly attached to the sole plate I2 of the iron l8 substantially parallel thereto by means of suitable screws 31 which pass through suitable apertures 89 in the thermostat base 38 so that the bimetallic element 48 is positioned in thermal communication with the iron sole plate. The adjusting member 42 is, therefore, inclined to thebimetallic element 48 and sole plate I2 and extends upwardly into the front depending portion 24 of handle Hi. The upper end of theadjusting member 42 is journaled within a suitable bracket 32 rigidly attached to the handle H; by means of a suitable screw 34, as hereinabove described. The control knob 22 is slidably attached to the adjusting member 42 through the cooperation of the knurled portion 43 thereof. The control knob 22 thus is capable of rotating the adjusting member 42 to regulate the operations of the bimetallic element 48 through the cooperation. of brackets 68 and arm 88 and permits said member to slide therethrough as it is rotated.

It, therefore, follows that an operator grasping the handle l8 of iron l8, in a normal, comfortable manner, may very readily adjust the operation of the thermostat through the inclined adjusting member 42 by merely rotating the knob by either her forefinger or thumb without shifting the position of her hand on the iron during the normal operations thereof, as previously set forth.

It, therefore, follows that the heating element of the iron is selectively adjusted by means of an adjusting member which extends forwardly and upwardly along an axis inclined to the sole plate and which has means attached thereto positioned above the front portion of the iron and within the depending front portion of the handle engageable by an operator's hand during the normal operation of said iron for selectively deterniiriizing the operating temperature of the sole p a e.

Various other modifications may be made in the device embodying our invention without departing from the spirit andscope thereof, and we desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and the appended claims.

We claimas our invention:

1. In a sadiron, an iron body having a sole plate, a handle attached to said iron body and standing portion, a grip portion and a comprising a front upstanding portion, a rear uption extending rearwardly from said tion, said handle having an opening in its surface disposed near the inner junction of the front upstanding portion and the skirt portion, a thermostat disposed near the central portion of said sole plate for controlling the temperature of the iron body, said thermostat embodying an adjusting shaft extending along an axis inclined forwardly and upwardly from said thermostat with respect to the sole plate and terminating within the handle and means rotatable about the axis of said shaft near the upper end of said shaft and having a rotatable surface protruding through said opening in said handle and engageable between an operator's thumb and forefinger extended froma natural gripping of said grip portion so as to be operable by one or both extended digits for selectively determining the operating temperature of the sole plate, said axis of said adjusting shaft being approximately perpendieular to a plane defined by said digits.

2. In a sadiron, an iron body having a sole plate, a handle attached to said iron body and comprising a front upstanding portion and a rip portion extending rearwardly from the upper skirt POrfront por- T end of said front portion, said sadiron having an opening in its surface. disposed near the lower end of said front upstanding portion and on the rear or inner side thereof, a thermostat disposed near the central portion of said sole plate for controlling the temperature of the sole plate, said thermostat embodying an adjustable shaft for adjusting the temperature setting of the thermostat, said shaft extending along an axis inclined forwardly and upwardly from said thermostat with respect to the sole plate and terminating within the handle, and manually operable means rotatable about the axis of said shaft and connected to said shaft for rotating the same, said means having a portion protruding through said opening and naturally engageable by an operator's thumb while maintaining a normal, comfortable grip on said grip portion during the nor-. mal operation of the sadiron for selectively determining the operating temperature of the sole plate by movement of said means by the opera.- tors thumb, the shaft being disposed at such an angle that the operator's thumb while so extended is disposed substantially in a plane norznal to the axis of the shaft.

EARL K. CLARK. JOSEPH S. WOJCIK.

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