US2424150A - Thermostat - Google Patents

Description

July 15, 1947. E. K. CLARK ETAL 2,424,150

I THERMOSTAT Original Filed March 24, 1941 3 Sheets-Sheet 1 wrmsssss: I V INVENTORS Earl 1.. Clark and Joaqp/z .SIh/ajcik.

' ATTRNEY July 15, 1947. E. K. CLARK AL IHERMOSTAT Original Filed March 24, 1941 3 Sheets-Sheet -2- eta! ' INVENTORS Ear! A. Clark and Jog eph 5. M ojcz'k.

A'fioRN'EY V WITNESSES:

July 15, 1947. E. CLARK ET AL THERMOSTAT Original Filed March 24, 1941 3 Sheets-Sheet3 .INVENTORS Clark and Ja pb S. l l/ajalf.

. Earl/K WITNESSES:

' ATTORNEY Patented July 1 5, 1947 THERMOSTAT Earl K. Clark and Joseph s. Woicik, Mansfield,

Ohio, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application March 24, 1941, Serial No. 384,918, now Patent No. 2,398,579, dated April 16, 1946. Divided and this application February 29, 1944, Serial No. 524,386

thermostat for an iron which embodies a bimetal:

lic element fulcrumly retained by means of one end thereof by a supporting structure and which has an adjusting member inclined to the bimetallic element which in one operating position is adapted to retain the movable end of the element in an open position.

A further object of our invention is to provide a thermostat for an iron having a base or supportin structure which fulcrumly or rockably receives a bimetallic elementand 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 about its fulcrum.

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

Yet another object of our invention is to provide a thermostat having a rotatable adjusting screw with an enlarged diameter friction and stop memher 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.

In the accompanying drawings:

2 Claims. (Cl. 200-139) 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;

Fig. 3 is a view similar to Fig. 2 illustrating the preferred form of a thermostat associated with the iron; t r

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 contacts in 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-VIII 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-XII 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 l0 having a working portion or sole plate 12, a heating element i4 for supplying heat thereto, a handle l6 for operating the iron, a regulating device or thermostatic structure l8 embodying an adjusting member 20 I which extends forwardly and upwardly so as to be inclined to the sole plate I2, and a control knob 22 positioned within the handle ii at the point of maximum ease and quickness of operation by the hand of an operator during the normal operation of the iron.

The iron structure In embodies a sole plate l2, a heating element l4, preferably of the sheathed type and cast therein, and a handle structure It.

The handle structure I6 comprises .a. front de-.

notch or opening 26 is located within the inner surface of the dependin portion 24 of handle 16 for receiving the control knob 22 for a purpose to be hereinafter described.

The thermostat i ii embodies a supporting strutt ture 28 and a bimetallic member 30'attached The supporting structure 28-s'ubsta-ntially encases the bimetallic element '30 and is thereto.

adapted to rigidly attach the structure to the sole plate i2 of the iron Ill. The thermostatic structure l8 per se forms no part of the present invention and need not be further set forth here, being more fully described and claimed in E. K. Clark Patent No. 2,194,999, assigned to the as,- signee of this application.

Th thermostat I8 is, in this instance, mounted at an angle to the sole plate l2, whereby the adjusting member therefor is inclined to the plane of such sole plate. The adjusting member 20 is thus adapted to extend forwardly and upwardly with respect to the sole plate I: and to extend into the depending portion 24 of the handl it. The upper end of the adjusting member 20 is journaled within a suitable bracket 32 attached to the handle l6 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 control knob 22 is positioned upon the knurled portion of the adjusting member 28 which prevents any relative rotative movement therebetween whereby said knob can rotate the adjusting member 20 in response to the rotated movements thereof. However, the cooperating knurled portions of member 20 and knob 22 permit said member 20 to slide longitudinally with respect to the knob 22 as the knob 22 rotates 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 IS. The control knob20 extends inwardly through the depending portion 24 of the handle l6 and is partially exposed.

It will be noted that by reason of the structural arrangement set forth, the knob 28 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 immediately is in a position to rotate the knob. No shifting of the operators hand as a whole and no groping for the adjustable knob or halting the ironing operation while the operator stops to look for the knob before using the same is required, contrary to the requirements of all previous automatic irons of which we are aware. The knob 28 is thus in a position where the operator, without stopping to look and without shifting her grip, naturally and automatically places her thumb or index finger in a position to rotate 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 inline 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 th comfortable grip is required. Further, since, no delays are necessary in making thermostat adjustments, the total time of ironing a batch of goodsmay be reduced.

Referring in particular to Figs. 3 to 12, inclusive, we show a preferred form of a thermostat for operation in an iron in keeping with the teachings hereinabove disclosed. Said preferred theri 4 mostat 3i embodies a base 28, 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 supports stationary contacts 44, fulcrumly retains a portion of the bimetallic element 48, and threadedly supports the adjusting member 42. Said base or support 38 embodies a main flat central portion 45 with a downward and outwardly extending end portion 46 at one end thereof and an upwardly substantially parallel fiat portion 48 at the other end thereof, joined by an inclined portion 41. A substantially rectangularly-shaped aperture 58 is formed within the end portion 44 and the main portion 45 of the base 88 for receiving one end of the bimetallic element 45, as hereinafter described. A centrally located upwardly extending ear 62 on end portion 45 extends into the aperture 50 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 th plane of the main portion. Said internally threaded member 49 receives the adjusting member 42, as hereinafter described.

The bimetallic element 48 comprises, in this instance, an elongated inherently snap-acting member having end portions 52 and 52 joined by a central strip 54 and to exterior strips 55. The end portion 52 has a centrally located notch 5| extending inwardly from the edge thereof. The exterior strips 55 are corrugated at substantially their midpoints to effectively reduce their length to make the bimetallic element 48 inherently snap-acting in keeping with the teachings of P. R. Lee, Patent N0. 2,259,312, issued October 14, 1941, and assigned 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 28 for rigidly attaching the central strip 54 of the bimetallic element 48 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 40 by suitable rivets 59 (see Figs. 9 and 10). The plate 58 extends outwardly from the element 40 along the longitudinal axis thereof and has rigidly attached, preferably by rivet 54, to its upper surface a flanged bracket or fingerlike member 88 which extends upwardly and backwardly over the element 40. An outwardly extending finger 5| integral with the upper portion of the bracket 50 is offset therefrom to cooperate with the adjusting member 42, as hereinafter described.

When the bimetallic element 40 is rigidly attached to the supporting structure by means of rivet 56, the fulcruming plate 58, attached to the end portion 52, extends outwardly through the aperture 50 in the base 38, permitting the fulcruming plate 58 to rest against the centrally located upwardly extending semi-circular ear 52. 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 5| cut therein, it follows that the car 52 engages the fulcruming plate 58 without engaging the bimetallic element 48. However, the cooperation between the ear 82 and iulcrumin plate 58 is on a line passing alon the end of the element48. 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 followsthat the bracket 88, attached to the plate 58. extends above the base 38 for cooperatlng with the adjusting screw 42, as hereinafter described. I

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 plate 58 engaging the bracket 68 and fulcruming plate 58 so as to bias the fulcruming plate 58 into engagement with the ear 82 in the depending portion 46 of base 38. The resilient member 14 thu "keeps the fulcruming plate 58 in contact with the ear 62 of base 38 at all times. I

An irregularly shaped calibrating arm 88 is rotatably attached to the bracket 88 in juxtaposition therewith by means of a suitabl rivet 89. The calibrating arm 88 has an outwardly extending portion 83 substantially circular in shape which is adapted to cooperate with the adjusting 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 movements 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 88 as an axis when the adjusting screw 42 is rotated. However, since the arm 88 is rigidly attached to the bracket 88 after the thermostat is calibrated, as hereinafter described, it follows I that such longitudinal movement of the adjusting member-42 is transmitted to the bracket 58 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 movabl contact structure 84 .is insulatedly attached to the second (shown as right-hand) end portion 53 of the bimetallic element 48 by means of a suitablerivet 68. The movable contact structure 84 includes a loosely mounted bridging member 68 having upwardly extending contact portions 18 which arespherical in shape.

--:'iIn:.-.addition, the lower head of the rivet 88 is similarly spherical in shape. Specifically, the 'contact portions 18 of the bridgin member 88 and. the lower surface of the rivet 88 are posi- ,tionedone with respect to the other so as to be segments of an identical sphere.

This Structure thus permits a uniform switching gap -A (Fig.

- at all operating temperatures of the bimetallic element and all angular positions ofthe contact The contact portions 18 of the movable bridgin member 88 are adapted to cooperate with the stationary contacts 44 :which are insulatedly attached to the upper portion 48 ot the base 38 in any well known manner.

I .Suitable terminal members are rigidly attached to the stationary contacts 44 to permit such contacts 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 member to independently disengage the cooper- 'tacts.

ating 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 uppertportion 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 48 substantially parallel to the portion 48 of base 38. A suitable stop'scre'w 88 is threadedly engaged into the member 18 and is aligned with the spherical head portion of the rivet 88 so as to determine the contact gap A (Fig. 5) or the space between the rivet 86 and stop screw 88 when the thermostat is in its closed or operating position. It isto 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.

edly 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 base38, and the bimetallic element 48 including fulcruming plate 58 and bracket 88 are rigidly attached to the main portion 35 of base 38 by means of rivet 58 attachedto the central strip. The resilient finger 14 is then rigidly attached to the base 38 to bias or retain the fulcruming plate '58 in direct contact with car 62 at all times. The stop assembly including shaft 16, bracket 18,

to the upper portion of base 38 and the stop screw 88 is adjusted so as to provide the desired contact gap A.

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 movable end 53 of the bimetallic element 48 downwardly, disengaging the cooperatingcon- A stop lug or washer-like member 84 having a radially protruding portion 85 is then fitted upon and rigidly attached to the lower portion of adjusting screw member 42 so that the protruding portion 85 of lug 84 engages a resilient stop pin 86 (Figs. 4 and 7),rigidly attached to the supporting structure or base 88. In other words, the position just described is one limit of the adjusting screw, namely, the off" position of the thermostat. The adjusting 'screw 42 is then rotated back as far as it will go, such movement being limited by the stop lug 84 engaging the resilient stop bracket 86. (See Figs. 4 and 7.) This position corresponds to the upper limit or high position of the thermostat.

The thermostat, with a calibrating screw 63 positioned through a threaded aperture 65 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 40, has increased in temperature and has become stable in operation at the high value thereof, the thermostat is removed from the bath. The calibrating screw 83 threaded through fulcruming plate 58, is then run upwardly so as to engage the calibrating arm 88. A continued upward move ment of the screw 63 then causes the fulcruming plate 58, attached bracket 80, and the end portion 52 of bimetallic element 48 to rotate in a counterclockwise direction about the car 62 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 is rigidly attached to the base 38. Upon the continued changing in curvature of element 48 due to the upward movement of calibrating screw 63, said element will snap to its closed or contact engaged position. This action determines the position of the fulcruming plate 88 and end portion 52 of element 48 for the "high setting of the thermostat. In addition, the position of bracket 68, with respect to calibrating arm 88 and adjusting screw 42, is thus individually ob tained for each thermostat. The bracket 68 and calibrating arm 88 are then spot-welded or rigidly attached together so as to permanently fix this angular position with respect to the adjusting member 42. The thermostat is thus calibrated between its manual openable or contactdisengaged position and its highest operating value, and the calibrating screw 83 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 value of the thermostat by being rotated within sleeve 48. This rotative movement causes the adjusting member 42 to be moved along its longitudinal axis and, in turn, to rotate the fulcruming plate 58 and end portion 52 of element 48 about ear 82 through the rigidly joined calibrating arm 88 and bracket 60 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 iulcruming position of the element with respect to the base 88 by means of bracket 60 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 man- 8 ually interrupt the circuit through the thermostat.

The thermostat as is rigidly attached to the sole plate l2 of the iron I 8 substantially parallel thereto by means of suitable screws 31 which pass through suitable apertures 88 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 the bimetallic element 40 and sole plate 12 and extends upwardly into the front depending portion 24 of handle I5. The upper end of the adjusting member 42 is journaled within a suitable bracket 32 rigidly attached to the handle l6 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 88 and arm 88 and permits said member to slide therethrough as it is rotated.

It, therefore, follows that an operator grasping the handle i6 of iron to, 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 determining the operating temperature of the sole plate.

Various other modifications may be made in the device embodying our invention without departing from the spirit and scope 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 claim as our invention:

1. A thermostat comprising a supporting structure, a bimetallic element having one end thereof fulcrumly retained by the supporting structure, a movable contact supported by the other end of said element cooperating with a stationary contact, an elongated adjusting member threadedly engaging the supporting structure permitting movement of said member along its longitudinal axis, means engaging the adjusting member for changing the fulcruming position of the element in response to the longitudinal movements of said member, and means engageable by the end of said member for bodily moving the free end of said element and dis engaging said contacts.

2. A thermostat comprising, in combination, a supporting structure. an elongated bimetallic element, embodying two end portions joined by three strips comprising a central strip and two exterior strips, said element being rockably retained, by means of one end portion, against the supporting structure and rigidly attached to the supporting structure by means of the central strip. cooperating contacts including a movable contact attached to the second end portion or said element, a resilient member attached to said second end portion and movable therewith, an adjusting member inclined to the axis of said element, and means engaging the member and said one end portion of the element for rocking said end portion to change the curvature of said element for varying the operating temperatures thereof, said adjusting'member, in at least one position thereof, engaging the resilient member and bodily moving said resilient member and end portion for disengaging the cooperating contacts.

EARL K. CLARK. JOSEPH 8; WOJCIK.

nun-moss crrr-zn The following references are oi recordin the 5 file of this patent:

' UNITED mm mum's Number Date Cunningham ....Aim.39.1-

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