STEAM IRON WITH DEVICE FOR PRESSURIZING WATER TANK

Abstract: A steam iron comprising a body (10) defining a handle (11), a lower metal plate (12) provided with electric heating means (13) and a vaporization chamber (15) with steam venting holes (16); the vaporization chamber (15) is connected to a separate water tank (17), by means of a duct (18) comprising a manually-­ operable control valve (19). The iron also comprises means (22) for pressurizing the water tank (17) comprising an air-pumping device (23) provided with a manual control member (28) located in the iron's handle (11).

Description: This invention relates to steam irons and is especially intended for an iron comprising a steam generation chamber connected to a separate water tank, in which a state of pressurization is maintained by feeding pressurized-air. At present on the market there are numerous types of steam irons in which the steam generation occurs inside a boiler that is either incorporated in the iron or separate and distinct from it. The emission of the steam through the iron's metal plate can occur continuously, or through the operation of a control valve. There is a second category of steam irons which consist in the use of a separate tank containing water at ambient temperature. The water contained in the tank is generally fed to the steam chamber of the iron by means, for example, of an electric pump provided on the water tank, or by means of a small manually-­ operated piston pump incorporated in the iron; the pump first sucks up the water from the tank and then feeds it to the steam-generation chamber, the user obtaining each such operation by pressing an appropriate push-button with a finger. In other irons sold the water at ambient temperature, contained in a separate tank, is fed to the iron's steam generation chamber through pressurization of the tank effected by continuously feeding pressurized air with an electric pump; a manual control valve acts to enable or alternatively to cut off the feed of water to the steam chamber. The steam irons noted above, despite offering good efficiency and good functioning, still have deficiencies and limitations deriving from their rather complex structure, arising from the use of costly and delicate components subject to malfunctions. In addition, in irons in which the steam is generated inside a boiler containing the water, there is a certain degree of danger. On the other hand, in irons in which the feed of water is effected at ambient temperature by pressurizing the air, there is a certain degree of unreliability because a relatively high pressure is generated which remains in the tank and in the ducts connected to the steam chamber, even when the iron is switched off and is not in use. Accordingly, it can happen that water, pushed by the air pressure still finds a way out by escaping through the holes in the iron's plate. An object of this invention is to provide a steam iron of the type comprising a separate water tank, containing water at ambient temperature, able to be appropriately pressurized by the same operator, which is of extremely economic and simple design, so eliminating all the disadvantages of the above-­ mentioned irons. A further object of this invention is to provide a steam iron, as described above, by means of which it is possible to maintain the state of pressurization of the water tank at an operatively effective and relatively low value, in this way exploiting purely the gripping action of the hand on the iron's handle, deriving from the reciprocating pushing movement, forward and backward, of the iron during its use. A still further object of this invention is to provide an iron as described above, in which the ironing action is exploited to automatically obtain both pressurization of the water tank and control of steam emission. What has been described can be achieved with an iron having the characteristics as claimed in claim 1; additional characteristics and alternative embodiments are defined in the dependent claims. In the drawings Fig. 1 is a longitudinal cross-sectional view of a steam iron, according to an embodiment of the invention; Fig. 2 is enlarged detail of the water tank of the iron in fig. 1; Fig. 3 and 4 show further characteristics. A first embodiment of the iron according to the invention will be described hereunder with reference to figures 1 and 2. Figure 1 shows a general type of iron comprising an upper body composed of several parts, having a handle 11 that is gripped by hand. Fixed below the body 10 is a metal plate 12 comprising an electrical heating resistor 13, directly or indirectly connected by a thermostatic switch, not shown, to an electric power cable 14. The iron's plate 12 has, at its front end, a steam generation chamber 15 which is provided at its base with venting holes 16 through which the steam generated escapes. The steam chamber 15 is fed with water at ambient temperature contained in a water tank 17, separate and distinct from the iron; the water is fed through a duct 18 comprising a control valve 19 manually-­ operable in the way described below. The duct 18, from the valve 19 inside the iron, extends outside to the tank 17 along a length of flexible duct 18a, of appropriate length, while 18b indicates the length of ducting which connects the valve 19 to the steam chamber 15. The tank 17 is hermetically sealed and contains a quantity of water 17a which can be introduced through an inlet opening 20 sealed with a plug member 21 performing an initial pressurizing action, as explained below with reference to figure 2. As previously stated, the water tank 17 is appropriately pressurized by feeding the tank with pressurized air by means of an air-pumping device 22 incorporated in the iron; the pumping device 22 is automatically operated by the user's hand as it grips the handle, through the effect of the repeated forward and backward movement of the iron during each ironing operation. The air inside the tank 17 is constantly maintained at a relatively low working pressure, as a result of the continuous and repeated pumping action automatically exerted by the user's hand. The pumping device 22 has been represented diagramatically in the form of a bellows pump connected to the water tank 17 through a non-return valve 24, of the diaphragm type for example, to a duct 25 whose portion 25a outside the iron is composed of a flexible tubular element. At the same time the pump 23 is connected to the environment outside through a non-return valve 26, of the diaphragm type for example, acting in the opposite direction to that of the valve 24. The bellows 23 of the pump or, more generally, the moving member of the pump 22 is operatively connected, for example through a guided rod 27, to a manually-­ operable pushing member 28; this member 28 comprises or defines a movable part of the iron's handle 11. In the case shown, the pushing member 28 is composed of a lever 29 on which is fixed a push-button or key 30 part of which protrudes out of an opening in the handle 11. The lever 29 is hinged at 31 at one of its ends to the iron's body 10 and is subject to the action of a biasing spring 32 which tends to raise the lever 29 and the key 30 to the condition in which the pump 23 is completely extended. As previously stated, the water is fed to the vaporization chamber by the air pressure inside the water tank 17 and is controlled by the valve 19. This valve 19 can be driven separately from the pressurization pump 22; however, according to another aspect of this invention, it is possible to operate the valve 19 with the operating lever 29 of the pressurization pump 22, simultaneously with the pump. Accordingly, the lever 29 in addition to operating the pump 22 also operates the small piston or movable member 33 of a slide valve 19 which, according to the axial position of its sliding member 33, enables or prevents communication between the duct 18 from the water tank 17 and the duct 18b connected to the vaporization chamber 15. It will be clear that instead of the slide valve 19 and the air pump 22 shown, it is possible to use other components of a different design, but suited to perform the same functions. Figure 2 of the drawings shows a further characteristic of the iron according to the invention; this figure shows a particular shape of the closing plug member 21 of the water tank 17, which enables provision of pressurization every time that the tank is replenished, by means of the same closing member 21. In particular the closing member 21 comprises a piston element 21a which extends inside of an elongated cylindrical mouth 20 defining the charging inlet of the tank 17. The piston 21a of the closing member 21, near to its lower end, has an O-ring 34 that can form a seal against the internal surface of the cylindrical mouth 20. It is therefore clear that after the tank 17 has been replenished with water, by pushing the piston 21a fully down, in the mouth 20, a certain initial pressurization action of the air held in the tank is obtained which enables initial functioning of the iron. Finally, in fig. 1, 35 diagramatically indicates a non-return valve inside the water tank 17, located in the inlet opening of the duct 25a for feeding pressurizing air. The working of the device is as follows: the iron is firmly gripped in the hand by its handle 11 and moved repeatedly forward and backward, pressing and alternatively releasing the pressure of the hand on the iron's handle as the iron moves. This repeated dynamic action of applying and releasing pressure by the hand on the iron's handle 11 and in particular on the control member 28 of the pressurization pump, causes a matching repeated reciprocating actuation of the pump. In fact, during backward movement of the iron, the pressure on the control member 28 is relieved allowing the pump 23 to extend and to suck in air from outside; conversely, during forward movement of the iron, the greater pressure or thrust exerted by the hand on the handle and therefore on the control member 28 results in the compression of the pump and in the feeding of a certain quantity of pressurized air into the water tank 17. The water tank 17 is consequently pressurized and maintained at an appropriate pressurization value depending on the air pressure generated by the pump 23, which may accordingly be contained at relatively low values, adequate for ensuring correct functioning of the iron but such as not to cause leakage or accidental escape of water from the iron, when it is not in use. Additionally, the air-pumping action is obtained by exploiting the variation in thrust exerted by the hand on the iron's handle, so making possible an extremely simple, reliable, low-cost, highly functional apparatus, in which the air pressure on the water contained in the tank 17 is maintained at a constant value, never excessive or dangerous. Since actuation of the pump 22, in the example in fig. 1, occurs in step with an simultaneously with the actuation of the valve 19, not only is pressurization of the air in the tank 17 obtained but so, too is the opening at the same time of the valve 19, which accordingly enables a certain quantity of water to pass from the water tank 17 to the vaporization chamber 15, where the water fed rapidly evaporates in the intense heat and finally escapes under pressure through the holes 16 in the plate 12. During pauses while ironing, when the iron is relinquished, the tank 17 maintains its pressurization without the latter increasing dangerously, due to the inaction of the pump 23. Figures 3 and 4 of the appended drawings show a further variant of the iron according to the invention in which use is made of an adjustable slide valve in the duct feeding water to the vaporization chamber 15, in order to adjust the quantity of water fed, to the point of stopping it, while maintaining functioning of the pressurization pump. Figures 3 and 4 show two different extreme operative conditions; in particular figure 3 shows the "dry" functioning condition of the iron in which no steam is delivered, while figure 4 shows the condition of maximum steam delivery. In figure 3, the slide valve 19 comprises a cylindrical hollow body having a water inlet 19a and a water outlet 19b; inside the body of the valve 19 there is a sliding element or piston 33, fitted with a first or lower toroidal gasket 36, a second or upper toroidal gasket 37 located towards an enlarged head portion 39 and a third toroidal gasket 38 between the gaskets 36 and 37. The head portion 39 of the sliding element has a cavity 40 in which is provided or positioned a circular cam 39a having a surface inclined towards the bottom of the cavity. The sliding element 33 of the valve extends downwards with a sliding stem (41) into a guide hole 42 at the lower end of the slide valve body 19, where a thrust spring 41a acts on the piston 33 to push it upwards. The head portion 39 of the sliding element 33 has in its turn a protruding edge 43 designed to come into contact with a ring-shaped stopping shoulder 44 in an enlarged hole 45 at the upper end of the slide valve 19. As stated above, the slide valve is adjustable; accordingly it comprises means for adjusting the position of the sliding element 33 so as to vary the quantity of water fed to the vaporization chamber. These adjusting means comprise the cam 39a at the upper end of the slide valve and a thrust member 46 against which one end 29a of the air-pressurization pump's control lever bears. The thrust member 46 has a protrusion or tooth-like projection 47 which slides along the surface of the cam 39a, between the condition of figure 3 in which the tooth 47 bears against the bottom of the chamber 40, corresponding to dry functioning of the iron, and the condition of figure 4 in which the tooth 47 bears against an upper flat part of the cam 39a and in which the supply of water and the emission of steam are at maximum. The thrust member 46 also comprises a shank portion 48 which extends upwards and which slides axially in a seat 49a of a push-button or rotating control member 49 projecting on the outside of the handle 11 or outside of the iron. The shank 48 and the seat 49a have opposing flat surfaces so that rotation of the push-button 49 transmits rotary motion to the thrust member 46, thereby making the tooth 47 slide on the cam 39a to vary and adjust the operative position of the sliding member 33 with respect to the cylindrical body of the slide valve 19. More exactly, the action of the tooth 47 on the cam 39a distances or brings closer the two components by moving the relative position of the sliding member 33 which however always maintains a pre-set stroke length, equal to the fixed displacement of the control lever 29a. As a result of the relative displacement of the stroke of the sliding member 33 with respect to the valve body 19, the intermediary gasket moves between positions 38 and 38′ preventing the circulation of water - drying functioning. In fig. 4 by contrast, the action of the tooth 47 on the cam 39a has moved the stroke of the sliding member 33 downwards; accordingly, the intermediary gasket of the sliding member 33 will take up the positions again indicated by reference numbers 38 and 38′ - functioning with maximum steam emission. Clearly, corresponding to intermediate positions of the tooth 47 on the cam 39a there will be matching intermediate positions of the sliding member 33 for choking the flow of water to the evaporation chamber.

Claims: 1. A steam iron comprising an upper body (10) provided with a handle (11), a lower metal plate (12), said plate comprising electric heating means (13), and a steam generating chamber (15) with venting holes (16) for the steam, said steam chamber being connected to a separate water tank (17) by means of a duct (18) comprising a manually-operable water control valve (19), and means 22 for pressurizing the water tank (17), characterised by the fact that the pressurization means (22) comprise a manually-opera ble air-pumping device (23), positioned inside the body (10) of the iron, said pumping device (23) being connected to the water tank (17) and to the outside environment through respective non-return valves (24, 26), and a manual control member (28) operatively connected to the air-pumping device (22), said manual control member (28) partially protruding from the iron handle (11). 2. An iron as claimed in claim 1, further characterised by the fact that said manual control member (18) for the air-pumping device (22) is operatively connected to said water control valve (19). 3. An iron as claimed in claim 2, characterised by the fact that said water control valve (19) comprises a slide valve. 4. An iron as claimed in claim 3, characterised by the fact that the slide valve (19) comprises manually operable cam means (39a, 46, 47) for adjusting the position of the sliding member (33) of the slide valve (19). 5. An iron as claimed in claim 4, characterised by the fact that said cam means comprise a circular cam (39a) at the upper end of the sliding member (33) of the valve (19), and a thrust member (46) operatively connected to a manual control lever (29) of the air pressurization pump (23), said thrust member (46) having a projection (47) sliding along an inclined surface of said circular cam (39a) and being operatively connected to a control push-button (49). 6. An iron as claimed in claim 5, characterised by the fact that the thrust member (46) is connected so as to rotate with the control push-button (49). 7. An iron as claimed in claim 6, characterised by the fact that the thrust member (46) is additionally connected in an axially sliding manner with respect to said control push-button (49). 8. An iron as claimed in claim 4, characterised by the fact that a thrust spring is positioned between the sliding member (33) of the slide valve (19) and an end wall of the slide valve body (19). 9. An iron as claimed in claim 2, characterised by the fact that the water tank (17) comprises additional pressurizing means (21a) in the water-charging opening (20)of the tank (17). 10. An iron as claimed in claim 9, in which the water- charging opening (20) in the tank comprises a closing member (21), characterised by the fact that said additional pressurizing means comprise an elongated cylindrical opening (20) for charging the water and a piston member connected to said closing member (21), said piston member (21a) sliding with a sealing-tight fit along and inside the above-stated cylindrical opening (20). 11. An iron as claimed in claim 1, characterised by the fact that said manual control member (18) for the air-pumping device (22) comprises an element (30) defining a movable part on the iron's handle (11).

Inventors: DASSI, FRANCESCO
Applicants: MAGIC LINE S.R.L.
Application year: 1988
Main classification: D06F75
IPC codes: D06F75