Patent Publication Number: US-4651453-A

Title: Travel iron having controlled heat and compact storage

Description:
FIELD OF THE INVENTION 
     This invention relates to the field of compact, lightweight travel irons, and, in particular, to those made of plastic materials. 
     BACKGROUND OF THE INVENTION 
     In recent years travel irons have been made of all plastic, except for electrical components, and have included a water-containing reservoir containing a heater for the generation of steam. 
     The heater has usually been a pair of separated electrodes placed within the water; and the water may contain an electrolyte such as salt to aid in heating. Examples of these designs are found in Osrow U.S. Pats. Nos. 3,755,649 and 3,969,607. However, these electrodes often quickly corrode and cause problems of arcing and mineral buildup, so much so that efforts have been made to solve the resulting problems. See, for example, Santiago U.S. Pat. No. 4,190 762. Also, some of them are only operative in the normal horizontal position, and are unable to operate when used vertically. 
     Structures for the control of temperature have usually involved thermostats. Though some steamers, but not irons, have  included reservoirs to hold heated water, they have not been used in irons to heat and limit the temperature of the sole plate. See, for instance, Mazzucco U.S. Pat. No. 4,366,367 and Osrow U.S. Pat. No. 4,206,340. 
     In addition, not all such irons have been made for ready, compact storage. 
     SUMMARY OF THE DISCLOSURE 
     The present invention has a plastic housing defining a water reservoir with a sole plate, normally made of plastic, forming the lower surface of the reservoir. This results in the sole plate being heated primarily by the heated water in the reservoir. The highest temperature of the sole plate is, then, limited to that of boiling water. The sole plate may also includes steam outlets which are connected by a passageway within the housing to a steam inlet (at a level above the normal level of the water in the reservoir). 
     Rather than using electrodes to provide heat, an immersible PTC resistance heater assembly is used. As is known, the resistance of such a heater rises sharply when it reaches a known pre-determined temperature (the Curie point). This rise in resistance effectively serves to cut off flow of electricity until the unit cools, and, so, acts as a protective circuit in case the reservoir runs out of water. 
     The iron is made more compact, and more readily stowable, by having a detachable and reversible handle. The handle is removably and reversibly secured to the housing at the forward end of the housing. Each end of the handle has a downwardly extending portion; and the forward portion is secured to the housing. When stowing the iron, the handle is removed and reversed (turned upside down). This serves not only to make the entire unit more compact, but also provides a place about which the electrical cord may be wound for storage. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Turning to the drawings: 
     FIG. 1 is a perspective view of the iron of my invention; 
     FIG. 2 is an exploded view of the drawing of FIG. 1; 
     FIG. 3 is a longitudinal sectional view of the iron, showing the internal structure; 
     FIG. 4 is a side elevation of the iron with the handle in the storage position and the electrical cord wrapped around the unit; and 
     FIG. 5 is a side elevational view showing the iron being used in its vertical position to press clothes hanging on a rack. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A perspective view of my travel iron 10 is shown in FIG. 1. It includes a housing 12 made up of a lower housing 22 and an upper housing 26. It has a handle 14, a flat sole plate 16 (seen in FIG. 3), a removable and reversible handle 14, an electric cord inlet 18, and the cord itself 20. 
     Lower housing 22 includes the flat sole plate 16 and peripheral upwardly extending flanges 24. Flanges 24 fit the lower edges of upper housing 26 and are secured to it, preferably by ultrasonic welding. 
     The lower housing 22, including sole plate 16 and its upwardly extending flanges 16, define the lower portion of water reservoir 30. The full reservoir is defined by this and upper housing 26 including its rearward section 28. It will hold water when the iron is in either the horizontal or vertical position. The water level 31 in the reservoir 30, when horizontal, is shown in FIG. 3. If desired, a baffle plate 32 may be installed vertically in reservoir 30 to prevent sloshing of water. 
     As can be seen, water within the reservoir rests on the inner surface of sole plate 16. Consequently, the heat from this water passes through and serves to heat the sole plate and is the principal heat source for the iron. The sole plate 16 may be made of any material that will transmit, and can withstand, the temperature of boiling water, but, preferably is made of plastic. The plastic used should be of a type, such as polycarbonate, capable of transmitting sufficient heat to permit use of the unit as an iron and of withstanding the temperature of boiling water. 
     Since the sole plate 16 is heated by water, temperature control of the sole plate is achieved, i.e., it cannot exceed the temperature of boiling water. 
     The forward end of sole plate 16 contains a series of steam outlets 36. These lead into a generally conical steam passageway 33, the upper end of which is a steam inlet 34. As can be seen the inlet 34 is higher than the normal water level in reservoir 30. 
     The heating element used to heat the water and to create steam is an immersible PTC resistor assembly 40, which is preferably of rectangular shape. Assembly 40 includes a PTC element enclosed within metal components, the metal permitting the transfer of heat from the PTC resistor to the water, but also isolating the resistor from the water, making the resistor immersible. PTC assembly 40 is secured to mounting frame 43 and to flanges 45 and 46 by mounting screws 44 and is connected to a power source through electrical connection 47, cord inlet 18, and cord 20. Resistor assembly 40 fits within holding slots 42 at the rear of housing 26. As best seen in FIG. 3, PTC resistor assembly 40 is positioned at an angle of about 30° to the horizontal. This assures that it will be submerged in water whether the iron is held horizontally or vertically. 
     A PCT resistor is a heating device which provides resistive heat (resulting from current flow) as long as it is below a pre-determined temperature known as the Curie point. Above that temperature, its resistance rises sharply and so limits current flow to almost zero. As a result, it can be used for safety (thermostatic) purposes as well as temperature control. In the present cast, a resistor is used with a Curie point sufficiently high to convert water to steam, but low enough to turn the iron off when it runs low on wter. In this instance, the PTC resistor should have a Curie point above the boiling point of water and below the fusing temperature of the plastic material used in making the iron. Preferably, it should be sufficiently below the fusing point to also prevent excessive overheating of the iron. 
     Once the resistor is in place, rear section 28 of upper housing 26 is installed, preferably by ultrasonic welding, making reservoir 30 watertight. 
     Handle 14 has a downwardly extending portion 50 at its forward end and a similar downwardly extending portion 52 at its after end. Latching engagement arms 54 project forwardly from the lower end of portion 50 and include a resilient latch 64 mounted between them. 
     An outer shell 60 fits about the forward end of upper housing 26 and is secured to it. Shell 54 includes an opening 62 (FIG. 3) at its after end to receive arms 54 and latch 64. It also includes latch-engaging opening 66 at the top to engage and hold latch 64. Latch 64 is designed so as to releasably engage with opening 66 when handle 14 is in its normal position and also when it is upside down. Consequently, for stowage, the handle may be reversed, reducing the overall size of the iron. In addition, when handle 14 is reversed, after portion 52 points upwardly and so provides a convenient place in which to coil electric cord 20 (FIG. 4). 
     The forward end of outer shell 60 includes a removable, snap-in filler door 68. By removing the door, one may add water to the reservoir 38, the water entering just forward of conical passageway 33. 
     In operation, the iron is assembled with its handle in the upper position; and the iron is filled with water and plunged in. PTC resistor assembly 40 heats the water in reservoir 38, and the water then heats sole plate 16. Excess steam passes through inlet 34, passageway 33, and out steam outlets 36. As can be seen from the angular position of PTC resistor 40, water will be heated whether the iron is in a horizontal or vertical position. 
     When a substantial part of the water has been boiled off, resistor assembly 40 will go &#34;off&#34;, and so prevent the system from overheating. Upon refilling the iron, the assembly 40 will again go &#34;On&#34; and heat the water. 
     FIG. 5 shows the iron being used vertically to press a pair of pants 70 hanging on a hanger. It can be seen that the PTCR 40, because of its angular position in the reservoir, can still heat the water. In addition, steam can be emitted through conical passageway 33 and steam outlets 36. 
     When one wishes to store the unit, handle 14 is removed, reversed, and repositioned. This recesses handle 14 close to the upper surface of upper housing 26, with its rearward portion 52 pointing upwardly, providing a convenient place about which to coil electricl cord 20 (See FIG. 4).