US1591022A - Electrothermal contact mechanism - Google Patents

Description

July 6 1926.

. 2,591,022 G. A. DE LANGIE ET AL ELECTROTHERMAL CONTACT MECHANISM Filed April 11, 1923 2 Sheets-Sheet l Lem fie. #0 1 Pefcr D Q9 Patented July 6, 1926.

UNITED STATES PATENT OFFICE.

GODFREY A. DE LANGIE AND PETER DE LANGIE, F NEWPORT, RHODE ISLAND.

Application med A ru 11, 1923. Serial No. 831,458.

This invention relates to an electro-thermal control mechanism which is particularly adapted for use in connection with electric irons, sterilizers, and other electrically ,heated devices and appliances.

In the use of devices and appliances of the character mentioned, which are heated by means of an electric current, it is highly desirable to provide means for automatically 1o breaking 'the electric current through the resistance element when the temperature of the device or appliance has been raised to a redetermined point, and to effect the breakmg of the current with certainty and at a substantially fixed point on the temperature scale at all times.

The desiderata enumerated above are of great importance by reason of the wide use of electricity for thepurpose of heating appliancesof this character, the fact that in many cases the operator is more or less unfamiliar with the use of the electric current for the development of heat and consequently liable to become careless or negligent in 2 the regulation and control of the same, as

well as the necessity in many cases for preventing any material overheating of the apparatus by reason of the danger of destroying the electrical connections, causing injury to material, fires, etc. The principal object of the resent invention is to provide an improve electro-thermal control mechanism of s mple construction which is hi hly eflicient in operation and as readily adapte for use in connection with electrically heated devices and a pliances generally to insure a proper an certain breaking of the electric current at -or sub stantially at a predetermined point on the temperature scale.

A further object of the invention is to provide an improved electric iron structure having eificient means for breaking the electric circuit through the heating element at substantially a fixed tem erature, together with means for closing t e electric circuit when broken,

Qther objects and advantages of the invention relate to various improved details of construction and improved arrangement of the arts as will be more fully set forth in the. etailed description to follow.

Referring to the drawings: Fig. 1 is'a side elevational view of an atas atlttoa tachment for an electric iron or the like embodying one form of the invention.

Fig. 2 is an end elevation of the structure shown in Fig. 1.

Fi 3 is a sectional view, taken along the lme 33 of Fig. 2.

Fig. 4 is a sectional view, taken along the line 4-4 of Fig. 2.

Fig. 5 is a perspective view of the attachment as applied to an electric iron of the usual construction, certain portions being broken away to better illustrate the position of the operative parts.

Fig. 6 is a horizontal sectional view of a modified form of the/invention as applied to an electric iron, taken along the line 6-6 of Fig 7, and,

ig. 7 is a vertical sectional view of the structure shown in Fig. 6.

In that form of the invention shown in Figs. 1 to 5 of the drawings wherein one form which the invention may assume in practice is shown as an attachment for an electric iron, 1 designates a housing made. up of sections 2, 3 and 4, and adapted to be secured to a suitable part, as the cover 26, of an electric iron of the usual construction. The sections 2, 3 and 4 are secured together in any suitable or desired manner to hold the operative elements of the apparatus in proper position relative to each other and form a suitable housing for the same. Secured in suitable recesses formed in the sections 2 and 3 and held in position by the attachment of the sections 2' and 3 to each other are terminals 5 and 6 of an electric circuit adapted to be connected to a resistance element 7 by connections 8 and 9. The terminals 5 and 6 may be properly insulated from the sections 2 and 3 by insulated coverings 10 or the sections 2 and 3 may be formed of insulating material if desired. The electric connection 9 passes directly from the terminal 6 to its point of attachment to the resistance element while the terminal 5 terminates a slight distance from the end of the connection 8, the space there between being adapted to be bridged by a movable contact 11.

The contact 11 is suitably secured to a movable switch 12, as bya screw 13, and the switch member 12 is preferably pivoted pprtion of the housing. The

switch 12 may e formed of insulating mateloo rial or the contact 11 may be insulated therefrom in any desired manner. 'A block 16 is secured to one face of the switch member 12 by screws or other suitable fastening devices 17 the block 16 being provided at one end with inclined faces 18 and 19 for a purpose which will be more fully described here inafter.

A spring 20 is positioned within the housing and bears against. one side of the member 12 to force the same upwardly and thereby move 'the contact 11 to open the circuit through the resistance element when the switch member 12 is free to move in response to the action of the spring, and the member 12 has a, portion 21 projecting through one side of the housing to serve as a handle by which the, member 12 may be manually operated tomove the contact 11 to open or close the circuit through the resistance-element. A closed hollow elongated member 24 is provided which has a portion 25 adapted to be inserted beneath the cover 26 of the electric iron and extend along a part 27 of the iron and in proximity to the resistance element Twhereby the portion 25 of the member 24 may be influenced readily by the variations in temperature experienced by the iron when current is passed through the resistance element. The remaining portion of the member 24 is preferably flattened and curved as indicated at 28 and lies in a groove 29 formed in the section 3, the groove. or recess 29 being enlarged adjacent to the free end of the portion 28 to permit the free end of the portion 28 of the heat responsive member 24 to move to different positions under the influence of variations in temperature.

'The member 24 is hollow substantially throughout its extent and the ends thereof are closed to prevent the escape of air, gas or other suitable expansible material which expands as the temperature is raised and, in expanding, causes the bent'portion 28 of the member 24 to become straightened as in the well-known Bourdon tube. The free end of the portion 28 of the, heat responsive member is closed andis so positioned 'as to engage the face 18 of the block 16 at ordinary temperatures, as shown in Fig. 2 of the drawings, whereby the movable switch 12 and the contact 11 carried thereby are held in such position that the contact 11 will close the circuit through the resistance element. As the temperature of the iron increases the free end of the portion 28 moves to the left, as seen in Fig. 2, until when the maximum temperature which it is desired to produce is reachedthe free end of the portion 28 moves out of engagement with the face 18 of the block 16 and permits the switch '12 to be forced upwardly by the spring 20 to move the contact 11 to open position thus breaking the circuit through the resistance element.

VVh-enever it is desired to close the circuit, by moving the contact 11 into the position shown in Fig. 3, this may be done by manually pressing the'handle 21 downward. If the temperatureof the iron at such time happens to be above the temperature at which the switch is released the block 16 will move past the free end of the'portion 28 of the member 24 and the contact will be moved to closed position. In such case, however, the free end of the portion 28 of the member 24 will not engage the face 18 of the block 16 to hold the switch closed and the spring 20 will cause the switch to open and break the circuit through the resistance element as soon as pressure upon the handle 12 is released.

If,- however, the temperature of-the iron has fallen to a point below that at which the automatic mechanism is set to operate for opening the circuit before the handle 12 is manually actuated to close the circuit, the free end of the portion 28 of the member 24 will'have moved to the right as seen in Fig. 2 to such an extent as to "project beneath the edge of the block 16 so that the free end-of the portion 28 will engage the inclined face 19 of the block. Further pressure downward upon the handle 12 will then force the switch into the position shown in Fig. 2 and close the circuit through the contact 11. In this case the free end of the por tion 28 will hold the circuit closed until the temperature rises sufiiciently to again move the end of the heat; responsive member out of contact with the block 16 and thus permit the spring 20 tomove the contact and open the circuit.

While the switch may'thus' be actuated 'to automatically break the circuit when a desired temperature is reached, the switch may also be manually operated at any time to open the circuit by moving the handle 21 upwardly. If this is done when the free end of the heat responsive member occupies a position above the block 16, as shown in Fig. 2,. the inclined face 18 of the block will readil permit the block to force the free end 0 the portion 28 of the heat responsive member to the left, as viewed in Fig. 2, and thus allow the block to move upwardly whereby the circuit is broken.

An electric switch plug 30 of the ordinary type is shown in Fig. 5 as positioned on the terminals 5 and 6 to connect the same with the usual current sup 1y through the cord 31. Indicia such as if and 'On may be placed upon the housing 1 toindicate to the operator the position of the handle 21 when the circuit is open or closed.

From the above description it will be seen that a simple and efficiently operating form the structure, means is provided for automatically breaking the current throu h the resistance element of the iron at suc time as the temperature of the iron reaches a predetermined point to positively prevent over heating with consequent injury'to the iron or other materials.

Referring to that embodiment of the invention illustrated in Figs. 6 ,and 7 of the drawings, designates an electric iron provided witha base plate 36, a top plate 37 and an electric heating element 38 interposed therebetween. A layer of asbestos or other heat insulating material 39 may be placed over the plate 37, and a cover 40 may be secured to the iron in an usual or desired manner as by screws 41.. erminas 42 and 43 of an electric circuit are secured to the iron and suitably insulated therefrom, the terminal 43 being connected directly to the heating element 38 by a connection 44, while the terminal 42 is connected with the heating element through a pivoted switch 45. The switch 45 is shown in the form of an elbow lever and is mounted to swing about a pivot post 46. One of the arms 47 of the switch member is provided with spring contact members 48 which are adapted to engage the terminal 42 in one position of the switch and be separated therefrom when the switch is moved to its open position to break the circuit through the heating element; A flexible connection 49 extends from the arm 47 of the switch to the heating element whereby a circuit is established through the heating element when the parts occupy the position shown in Fig. 6 of the drawings. A resilient member 50 connects the arm 47 with a portion of the iron to move the switch to open the circuit when the temperature has reached such a point that the movement of the switch to open position is no longerobstructed by the heat responsive member.

A closed hollow heat responsive member 52 has a portion 53 embedded in the base 36. adjacent to the heatingelement 38 and a curved portion 54 extending above the asbestos layer 39. The heat responsive member may be of flattened tubular form with closed. ends, and may contain air or other material which is fluid at operating "temperatures and which expands with increase in temperature.

The free end 55 of the curved portion 54 of the heat responsive member is adapted to occupy the position shown in'Fig. 6 at temperatures below that at which the circuit is to be opened. In this position of the parts the end 55 contacts with the end of the arm 56 of the switch, as shown, to hold the switch against movement under the influence of the spring 50. The screw 41 serves as a stop to prevent excessive movement of the switch arm 56, and a coiled 52. In practice however contact may be made in various ways as b extending one of the spring contacts 48 into position to engage a contact in circuit with the heating element when the arts are in the position shown in Fig. 6. The arm 47 of the switch passes through a slot 58 in the cover 40 and is provided with a manually operable 'handle 59 bywhich the switch may be operated manually to either open or close the circuit throu h the resistance element 38 regardless o the position of the end 55 of the heat responsive member. The end 55 of the heat responsive member is rovided with inclined faces 60 and 61 whlch permit the end of the arm 56 .to slide thereover in either direction when the handle 59 is manually operated to either openor close the circuit through the heating element at tempera tures below that at which the switch is automatically operated to open the circuit to the heating element.

In the structure shown in Figs. 1 to 5 the terminals 8 and 9 may be'cut away to permit-the usual contact posts of an electrically equipped iron to pass up into the hous ng a suflicient distance to contact with and make an electric circuit with the terminals within the housing so as to permit the attachment to be applied to an electric iron without any modification of the electric circuit within the iron. 1

While the heat responsive member has been described throughout the specification as a closed hollow elongated member, since I the provision of an elongated portion pro vides a ready means for positioning a considerable portion of the member in heat receiving position relative to a heated part of the iron, it is to be understood that the heat responsive member'may be. formed in a variety of shapes and its parts arran ed in difierentways provided the said mem r is constructed of hollow form and closed to insure proper action on the part of the expansible material therein contained.

While the electro-thermal control mechanism herein described has been shown in connection with an electric iron structure in order to illustrate one form which the apparatus may assume in practice it is to be understood that the same is not confined to use in connection with electric irons but may be employed in connection with electrically heated devices generally for automatically breaking the current to prevent overheating while at the same time permit-i ting the current to be manually closed when the temperature of the heating element has been lowered below the point at which the automatically operating mechanism is set to function. elements are so constructed and arranged as to permit the current through the heatin element to be made or broken by manua actuation of the switch at temperatures below that at which the mechanism is automatically actuated.

It is to be noted that the employment of a closed hollow elongated heat responsive member of the character described as a control means for releasing the switch and permitting the switch-to'be opened by the resilient means provided for the purpose when the temperature has reached a predetermined point constitutes a simple and highly efi'icient automatic mechanism for breaking the current through the resistance element which is capable of being arranged to operate with a high degree of certainty and between extremely narrow limits of temperature. Thus there is provided an apparatus of this character-which insures. a certain and positive operation of the parts, which is adapted to operate at substantially any desired-temperature, and

I which is capable of such uniformity of operation as to prevent injury to the apparatus or materials by overheating.

What we claim is I 1. A. thermostatic control for electro-thermal mechanisms comprising a switch, and

a closed hollow heat responsive member havmg a curved end portion free to move 1n anunobstructed path with variations in temperature for releasing said switch at apredetermined temperature.

2. A thermostatic control for electro-thermal mechanisms comprising a circuit breaker for an electric circuit, a closed hollow elongated member-containing a heat expansible material and having a curved end portion movable into different positions in accordance with variations in temperature, said member normally holding said circuit breaking means in position to close the circuit but movable into position to release said circuit breaking means when the temperature reaches a predetermined point, and means circuit when released member.

for moving said circuit breaker to open the v by said elongated 3; A thermostatic control for electro-therma-l mechanisms comprising a spring actuated member for breaking an electric circuit, and a closed hollow member having a curved end portion normally holding said circuit breaking means in position to close the cir- In addition to the above the holding said circuit breaking member in po- I sition to close said circuit but movable into position to release the spring actuated circuit breaker and thereby open the circuit when the temperature has reached a 'predetermined point.

5. A thermostatic control for electro-thermal mechanisms comprising a circuit breaker manually movable to either open or close an electric circuit, spring means for moving said circuit-breaker into position to open the circuit, and a closed hollow heat responsive member having a curved end portion movable to different positions in a direction radially of the curve responsive to variations in temperature for normally holding the circuit breaker in position to close the circuit but movable into position to release the circuit breaker whereby the circuit breaker may be actuated by said spring means to open the electric circuit when the temperature has reached a predetermined pdiiit.

6. In an electro-tliermal control mechanism, a spring-actuated member movable into position to open or close an electric circuit, and a closed hollow fluid containing heat responsive member having a bodily movable end portion provided with an inclined surface engaging said spring-actuated member and adapted to hold said spring-actuated member in circuit closing position at ordi nary temperatures but movable under the influence of heat to release said spring actunism, manually operated means for closing an electric circuit, means for breaking the said circuit when the temperature reaches a predetermined point, said last named means including a. closed hollow elongated member havin a portion thereof bodily movable into ifierent positions responsive to temperature changes and adapted at normal temperatures to render said circuit breaking means inoperative.

9. In an electro-thermal control mechanism a manually operated switch for closing said circuit, resilient means for.moving said switch to open the circuit, and a closed hollow elongated fluid containing member having a portion bodily movable into different positions responsive to variations in temperature adapted to hold said switch in closed position at temperatures below a certain point and movable into position to render said resilient means operative to open the circuit when a certain temperature has been reached.

10. In an electro-ther1nal control mechanism, a manually operated switch for closing an electric circuit, resilient means for moving said switch to open the circuit, a closed hollow elongated fluid containing 'member, having a portion thereof bodily GODFREY A. DE LANGIE. PETER DE LANGIE.

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