US2981017A

US2981017A - Automatic water metering for steam iron

Info

Publication number: US2981017A
Application number: US834966A
Authority: US
Inventors: Edward G Tesmer; James A Shephard
Original assignee: MERRILL M KISTNER
Current assignee: MERRILL M KISTNER
Priority date: 1959-08-20
Filing date: 1959-08-20
Publication date: 1961-04-25
Anticipated expiration: 1978-04-25

Description

April 25, 1961 E. G. TESMER ET AL 2,981,017

AUTOMATIC WATER METERING FOR STEAM IRON 2 Sheets-Sheet 1 Filed Aug. 20, 1959 INVENTORS EDWARD G.TESMER JAMES A. SHEPHARD BY M M, Wi

ATTO R N EYS April 25, 1961 E. G. TESMER ETAL 2,981,017

AUTOMATIC WATER METERING FOR STEAM IRON Filed Aug. 20, 1959 2 Sheets-Sheet 2 VIM 5? FIG. 2

INVENTORS EDWARD G. TESMER JAMES A. SHEPHARD ATTORNEYS United States Patent AUTOMATIC WATER METERING FOR STEAM IRON Filed Aug. 20, 1959, Ser. No. 834,966

4 Claims. (Cl. 38-77) This invention relates to steam irons and, more particularly, to a steam iron construction characterized by control over the water supply to the steam generating chamber so that no water can be delivered to the chamber until it has reached a steam-generating temperature.

Steam irons of the flash-type are provided with a water reservoir above the sole-plate and with a valve which controls the flow of water from the reservoir to the steam-generating portion of the sole-plate. This valve is generally so placed that when the iron is turned up on its heel the valve is positioned above the level of water in the reservoir of the upended iron, and consequently there is no delivery of water to the steam generating chamber while the iron is in this position. When such an iron is turned on, it is customary to place the iron on its heel. In order to determine whether the iron is up to operating temperature, the user generally tilts the iron to a horizontal position and watches for the discharge of steam through the sole-plate ports. If the sole-plate is not yet up to a steam-generating temperature, the water which flows from the reservoir to the steam generating chamber is trapped in the chamber until the iron is again returned to a horizontal position. Then, if steam is generated from the incoming water the previously trapped water in the chamber is blown out of the steam ports in a display known as spitting. These discharged droplets of water, as distinguished from dry steam, will damage or spot many fabrics and consequently spitting is a characteristic of a steam iron which should be eliminated if possible.

We have now developed a water control device for a steam iron which completely eliminates spitting." This device is positive in its action in response to the soleplate temperature, as distinguished from the less positive of spring-like temperature-responsive devices using bimetal strips and the like. The positive action device of our invention opens the water-control valve only when the sole-plate has reached a predetermined temperature sufiicient to effect flash-steaming of the water, and the opening of this valve is thereafter progressively increased with an increase in sole-plate temperature so that throughout the starting-up period water is delivered to the steam generating chamber only at a rate at which the sole-plate can transform the water to steam.

The electric steam iron of our invention comprises a sole-plate having a steam-generating chamber, steam delivery channels in the sole-plate for directing steam formed in the generating chamber to openings in the lower face of the sole-plate, and a water-control valve adapted to control the flow of water from the reservoir to the steam-generating chamber. Pursuant to the invention, a mechanical linkage interconnects two portions of the sole-plate spaced a substantial distance apart, the coeflicient of expansion of the mechanical linkage being different than that of the sole-plate so that relative movement of one with respect to the other occurs as the temperature of the sole-plate changes. Connecting means ice is provided for translating this relative movement to the water-control valve so that the valve is opened to deliver water to the steam-generating chamber only when the sole-plate is at a temperature sufficiently high to transform the thus-delivered water to steam.

These and other novel features of the steam iron of our invention will be further understood by reference to the accompanying drawings in which Fig. l is a side elevation, partly in section, of a steam iron embodying the control device of the invention and Fig. 2 is a plan view, partly broken away, taken along line 2-2 in Fig. 1.

The steam iron shown in Fig. 1 comprises a sole-plate 10 provided with a cover plate 11 which cooperates, as more clearly shown in Fig. 2, with various raised portions of the sole-plate, including the heating element casing 12, to define a steam-generating chamber 13 and passages 14 leading from the chamber to steam outlet ports 15 in the sole-plate. Above the sole-plate and its cover is mounted a water reservoir 16 provided with an outlet 17 communicating through the cover plate 11 with the interior of the steam-generating chamber 13. The reservoir outlet includes a valve seat 18 and a valve stem 19 the lower portion of which cooperates with the seat to provide a water-control valve between the reservoir and the steam-generating chamber. The reservoir is enclosed by a body shell 20 for the iron, and at the top of the shell a handle body 21 is mounted.

The temperature-responsive element of our novel steam iron construction'is shown in Fig. 1. It comprises essentially a control bar 22 advantageously extending substantially the full length of the sole-plate. At the rear of the sole-plate the control bar 22 is anchored in a boss 23 through which the bar passes. At the front end of the sole-plate the control bar 22 is pivotally secured at 24 to the lower end of a rocking lever 25. The rocking lever is also pivotally mounted at 26 to a stud 27 struck up from the sole-plate. The upper portion of the rocking lever 25 is arcuately curved to conform to the contour of the space between the body shell 20 and the reservoir 16 as it extends upwardly toward the base of the handle body 21.

The resulting mechanical linkage between the front and rear ends of the sole-plate is initially set so that when the sole-plate is cold the upper end of the rocke ing lever 25 is near its lowermost position adjacent the top of the reservoir 16. The setting is made by lock nuts 28 on the rear end of the control bar 22. By choosing a metal for the control bar having a substantially lower coefiicient of expansion than the sole-plate, it will be readily apparent that the length of the sole-plate will increase as it becomes hot and that the relatively smaller increase in the length of the control bar 22 will cause the lower end of the rocking lever 25 to be pulled rearwardly and thus raise the upper end of therocking lever.

The resulting movement of the rocking lever 25 actuates the water valve control mechanism which is mounted on a forward portion of the handle body 21. This control mechanism includes a lift rod 30 vertically mounted in position above the upper end of the rocking lever 25. The upper end of the lift rod 30 is positioned immediately below a side arm 31 mounted on the upper end of the water control valve stem 19. The valve stem is normally held in its lowermost or valve-closed position by a coil spring 32. Thus, upward movement of the upper end of the rocking lever 25, as the sole-plate becomes hot and expands, raises the lift rod 30 and thereby raises the side arm 31 and the valve stem 19. By proper choice of the amount of space or play between these parts, the control mechanism can beset so that the valve stem is not 3 raised at all until the sole-plate reaches a steam-generating temperature, say 250 F., and that the valve stem is progressively opened farther until the sole-plate has reached its normal operating temperature.

The normal operating temperature of the sole'plate is controlled by the temperature-sensitive device used to control electrical contacts in the line between the power supply and the heating element 12. In the iron construction of our invention, the same temperature-responsive device used to operate the water-control valve is used to control these electrical contacts. Thus, one electrical contact 33 is mounted on an arm 34 secured to a bushing 35 slidably mounted on an upper portion of the lift rod 30. A coil spring 36 encircling the bushing tends to hold the bushing 35 downwardly against a shoulder 37 formed by a reduction in the thickness of the upper portion of the lift rod 30. The other electrical contact 38 is similarly mounted on an arm 40 secured to a lower bushing 41 slidably mounted on a lower portion of the lift rod 30. The exterior surface of the lower bushing 41 is threaded and engages similar threads in an annular ring 42. The annular ring is provided with teeth which engage the internally-toothed portion of a larger outer ring 43 mounted at the base of a hollow control knob 44 surrounding the entire temperature-control assembly. Thus, by tuming the control knob 44, its internally-toothed ring portion turns the smaller annular ring gear 42 surrounding the lower contact bushing 41 and thus raises or lowers this bushing with its attached electrical contact 38. The vertical movement of the lift rod 30,,actuated by the mechanical linkage consituting the thermally-responsive device of the invention, raises and lowers the upper electrical contact 33. Accordingly, the position of the lower electrical contact 38 determines the temperature at which the upper contact makes or breaks the circuit, and the upper contact 33 makes or breaks this circuit in response to the temperature of the sole-plate.

It will be seen, accordingly, that the single temperature-responsive device in the steam iron of our invention actuates not only the temperature control of the iron but also actuates the water-control valve between the water reservoir and the steam-generating chamber. In the event, however, that the iron is to be used without steam generation, a steam-control knob 45 is provided which has a depending arm 46 arranged so that when the knob is turned the arm will swing the water-control valve stem side arm 31 around until it is out of the plane of the vertical movement of the lift rod 30. With the side arm in this position, the coil spring 32 holds the valve stem in its downward or valve-closed position so that no water will enter the steam-generating chamber. The temperature-responsive device thus continues to actuate the electrical contacts to maintain the desired sole-plate temperature while at the same time by-passing the water valve control.

The operation of the water-control valve is effected, pursuant to the invention, by a positive action created by the relative movement between the sole-plate and the control bar 22. This movement, incurred by the force of expansion of the sole-plate, is directly translated to the water-control valve stem so that resistance to movement of the stern by the strong position-restoring springs is overcome. Moreover, the only controls available to the user are the choice of steam or non-steam ironing condition and the choice of operating temperature dictated by the fabric to be ironed. The user has no control over the water supply to the steam-generating chamber and thus the water-control can be pre-set during construction of the iron to give optimum water feed for all sole-plate temperature conditions.

We claim:

1. In an electric steam iron comprising a sole-plate having a steam-generating chamber, steam delivery channels in the sole-plate for directing steam formed in the generating chamber to openings in the lower face of the sole-plate, a water reservoir mounted above the sole plate, and a water-control valve adapted to control the flow of water from the reservoir to the steam-generating chamber, the improvement which comprises a mechanical linkage interconnecting two portions of the sole-plate spaced a substantial distance apart, one end of the mechanical linkage being anchored on the sole-plate and the other end being movably mounted with respect to the sole-plate, the coeflicient of expansion of the mechanical linkage being different than that of the sole-plate so that relative movement of one with respect to the other occurs as the temperature of the sole-plate changes, and connecting means operatively engaging the movably-mounted end of the mechanical linkage for translating to the watercontrol valve said movement of the mechanical linkage relative to the sole-plate so that the water-control valve is opened to deliver water to the steam-generating chamher only when the relative-movement between the soleplate and the mechanical linkage has reached a predetermined amount.

2. In an electric steam iron comprising a sole-plate having a steam-generating chamber, steam delivery channels in the sole-plate for directing steam formed in the enerating chamber to openings in the lower face of the sole-plate, a water reservoir mounted above the sole-plate, and a water-control valve adapted to control the flow of water from the reservoir to the steam-generating chamber, the improvement which comprises a mechanical linkage interconnecting two portions of the sole-plate spaced a substantial distance apart, the coefficient of expansion of the mechanical linkage being different than that of the sole-plate so that relative movement of one with respect to the other occurs as the temperature of the sole-plate changes, a pivoted arm mounted on the forward portion of the sole-plate, one end of the mechanical linkage being connected to one end of the pivoted arm, and connecting means for translating movement of the other end of the pivoted arm to the water-control valve so that the watercontrol valve is opened to deliver water to the steamgenerating chamber only when the relative movement between the sole-plate and the mechanical linkage has reached a predetermined amount.

3. In an electric steam iron comprising a sole-plate having a steam-generating chamber, steam delivery channels in the sole-plate for directing steam formed in the generating chamber to openings in the lower face of the sole-plate, a water reservoir mounted above the soleplate, and a water-control valve including an axially movable valve stem adapted to control the flow of water from the reservoir to the steam-generating chamber, the im provement which comprises a mechanical linkage interconnecting two portions of the sole-plate spaced a substantial distance apart, the coefficient of expansion of the mechanical linkage being different than that of the soleplate so that relative movement of one with respect to the other occurs as the temperature of the sole-plate changes, a pivoted arm mounted on the forward portion of the sole-plate, one end of the mechanical linkage being connected to one end of the pivoted arm, and a lift rod interconnecting the upper end of the pivoted arm and the valve stem so that the water-control valve is opened to deliver water to the steam-generating chamber only when the relative movement between the sole-plate and the mechanical linkage has reached a predetermined amount.

4. In an electric steam iron comprising a sole-plate having a steam-generating chamber, steam delivery channels in the sole-plate for directing steam formed in the generating chamber to openings in the lower face of the the sole-plate, an electrical heating element in the soleplate, a water reservoir mounted above the sole-plate, and a water-control valve adapted to control the flow of water from the reservoir to the steam-generating chamber, the improvement which comprises a mechanical linkage interconnecting two P r ions of the sole-plate spaced a substantial distance apart, one end of the mechanical linkage being anchored on the sole-plate and the other end being movably mounted with respect to the sole-plate, the coefficient of expansion of the mechanical linkage being different than that of the sole-plate so that relative movement of one with respect to the other occurs as the temperature of the sole-plate changes, connecting means operatively engaging the movably-mounted end of the mechanical linkage for translating to the Water-control valve said movement of the mechanical linkage relative to the sole-plate so that the water-control valve is opened to deliver Water to the steam-generating chamber only When the relative movement between the sole-plate and the mechanical linkage has reached a predetermined amount, a pair of electrical contacts, one of the electrical contacts being mounted in fixed position and the other being mounted for movement toward or away from the fixed contact, and electrical contact connecting means References Cited in the file of this patent UNITED STATES PATENTS 2,102,892 Fitzgerald Dec. 21, 1937 2,337,077 Woodman Dec. 21, 1943 2,749,633 Seek June 12, 1956 2,865,119 Pratt Dec. 23, 1958 2,903,804 Kistner Sept. 15, 1959 FOREIGN PATENTS 1,084,348 France July 7, 1954