Abstract:
A steam iron includes a sensor for detecting and measuring movement of the steam iron. The sensor is coupled to an actuator that regulates the flow of steam via a valve located between a steam chamber and steam outlets. The sensor can detect movement in three directions (X, Y, Z) and adjust steam generation based on speed of movement of the iron and tilt angle. A pre-heater is used to pre-heat water in a water chamber. The pre-heated water is provided to a steam chamber where it is later converted to steam.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to steam irons and more particularly to steam iron with controlled water flow and steam generation. 
     Steam irons are well known and have been in use for many years. Such irons have a handle and a base. The base includes a water reservoir, a steam chamber in fluid communication with the water reservoir, a heating element, and a base plate having a number of steam spray ports therein. Typically, the heating element heats water in the steam chamber to generate steam that may be expelled from the base plates via the steam spray ports in response to the user pressing a button. Thus, the amount of steam released from the iron depends in large part on the user. If the user presses the button for a prolonged period of time, all of the steam will be expelled from the steam chamber. 
     It would be advantageous to have a steam iron that can automatically control the generation and flow of steam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description of preferred embodiments of the invention will be better understood when read in conjunction with the appended drawings. The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements. It is to be understood that the drawings are not to scale and have been simplified for ease of understanding the invention. 
         FIG. 1  is a side, cross-sectional view of a steam iron in accordance with one embodiment of the invention; and 
         FIGS. 2A-2D  illustrate the operation of a steam iron in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of a presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the invention. In the drawings, like numerals are used to indicate like elements throughout. 
     In one embodiment, the present invention provides a steam iron including a heatable base plate having a plurality of steam outlets. A reservoir is provided for holding water and steam. A heating element is located near to the base plate and the reservoir for heating the base plate and for heating water in the reservoir and converting the water to steam. At least one steam pipe connects the base plate steam outlets with the reservoir that allows steam to move from the reservoir to the steam outlets and exit the iron. A first valve is located along the steam pipe between the reservoir and the steam outlets for regulating the flow of steam through the steam pipe. Steam may move from the reservoir to the steam outlets when the first valve is in an open position. A first actuator moves the first valve between the open position and a closed position. A sensor, coupled to the actuator, detects and measures a speed of movement of the steam iron. The actuator moves the first valve between the open and closed positions depending on the detected speed of movement. 
     In another embodiment, the sensor is three axis accelerometer that detects both speed and tilt angle of the steam iron and the actuator is a microcontroller that moves the valve between the open and closed positions depending on either or both of the speed of movement and the tilt angle of the steam iron. When the steam iron is moved at a predetermined speed and at a predetermined angle, steam is automatically expelled via the steam outlets. 
     A steam iron  10  in accordance with various embodiments of the present invention now will be described with reference to  FIG. 1 . The steam iron  10  has a heatable base plate  12  having a plurality of steam spray ports or outlets  14  therein. A reservoir is provided for holding water and steam. In one embodiment of the invention, the reservoir comprises a water reservoir  16  for holding water and a steam chamber  18  for holding steam. The water reservoir  16  is in fluid communication with the steam chamber  18 . The base plate  12 , steam outlets  14 , water reservoir  16  and steam chamber  18  are all well known elements of a steam iron to those of skill in the art and a detailed description is not required for a complete understanding of the invention. Further, although the water reservoir  16  and steam chamber  18  are shown as in the drawing as separate elements at particular locations and of particular size and shape, in fact, these elements may comprise various numbers, sizes, shapes and locations, and the present invention should not be limited by such features of these elements. 
     The iron  10  includes a heating element for heating water in the water reservoir  16  and converting the water to steam, and heating the base plate  12 . In one embodiment of the invention, the heating element comprises at least two heating elements. A first heating element  20  is located proximate to or integral with the base plate  12  for heating the base plate  12 . A second heating element  22  is located proximate to or integral with the steam chamber  18  for converting water in the steam chamber to steam. In another embodiment of the present invention, a pre-heating element  24  is located proximate to or integral with the water reservoir  16  for pre-heating the water stored in the water reservoir  16 . Although the heating elements  20 ,  22  and  24  are shown as adjacent to the base plate  12 , steam chamber  18  and water reservoir  16 , respectively, it will be understood by those of skill in the art that the heating elements may comprise various types of heating elements and be located at several different positions, such as adjacent to, near to, or integral with the base plate  12 , water reservoir  16 , and steam chamber  18 , respectively. Thus, the present invention should not be limited by the type, number, or location of the heating elements. 
     At least one steam pipe  26  connects the base plate steam outlets  14  with the steam chamber  18  and allows steam in the steam chamber  18  to move to the steam outlets  14  and exit or be sprayed from the iron  10 . A first valve  28  is located along the steam pipe  26  between the steam chamber  18  and the steam outlets  14  for regulating the flow of steam through the steam pipe  26 . When the first valve  28  is in an open position, steam may move from the steam chamber  18  to the steam outlets  14 , and when the first valve  28  is in a closed position, steam may not traverse the steam pipe  26 . Although only one steam pipe  26  and first valve  28  are shown, the steam iron  10  may have more than one steam pipe  26  that connects the steam chamber  18  with the steam outlets  14 . 
     In one embodiment of the invention, the steam iron  10  also includes a water pipe  30  connecting the water reservoir  16  with the steam chamber  18 . A second valve  32  is located along the water pipe  30  for regulating the flow of liquid between the water reservoir  16  and the steam chamber  18 . When the second valve  32  is in an open position, liquid stored in the water reservoir  16  may move to steam chamber  18 , and when the second valve  32  is in a closed position, liquid may not traverse the water pipe  30 . Although only one water pipe  30  and second valve  32  are shown, the steam iron  10  may have more than one water pipe  30  that connects the water reservoir  16  with the steam chamber  18 . 
     In one embodiment of the invention, the steam iron  10  includes first and second actuators for moving the first and second valves  28  and  32 , respectively, between their respective open and closed positions. In one embodiment of the invention, the first and second actuators comprise a microcontroller  34  that is electrically connected to the first and second valves  28  and  32 , and sends respective first and second actuator signals  36  and  38  to the first and second valves  28  and  32  to move the first and second valves  28 ,  32  between their open and closed positions. 
     A sensor  40  is coupled to the microcontroller  34  for detecting and measuring a speed of movement of the steam iron  10 . The sensor  10  sends the measured speed data to the microcontroller  34  and the microcontroller  34  generates the first actuator signal  36 , to move the first valve  38  between the open and closed positions, depending on the detected speed of movement. In one embodiment of the present invention, the sensor  40  comprises an accelerometer, such as a 3-axis accelerometer that can measure both speed and tilt angle of the steam iron  10 . In such embodiment, the microcontroller  24  receives the measured speed and tilt data from the sensor  40  and generates the first and second actuator signals  36 ,  38 , for moving the first and second valves  28 ,  32  between their open and closed positions. The generation of steam and the flow of liquid between the water reservoir  16 , the steam chamber  18  and the base plate steam outlets  14  are thus controlled. 
     The sensor  40  may comprise a Micro-electromechanical system (MEMS) sensor. MEMS dual axis accelerometers are presently available in small packages, on the order of 4 mm×4 mm×1.5 mm. Such devices operate on power supplies around 3v and provide signal conditioned voltage outputs for a variety of motion sensing, tilt sensing and inertial sensing features. For example, small tilt changes can be sensed using narrow bandwidths. Example MEMS sensors that may be used to realize the present invention are Freescale Semiconductor, Inc.&#39;s MMA7455L and MMA7456L accelerometers, which can be used for sophisticated portable electronics products. 
     The speed and tilt data provided by the sensor  40  to the microcontroller  34  are used as further described herein. In one embodiment, when the iron  10  moves faster than a first predetermined speed, the controller  34  generates the first actuator signal  36  to move the first valve  28  from its closed position to its open position. This would be the case for when the iron  10  is in a steam mode and a user is moving the iron  10  back and forth over an item to be ironed. The sensor  40  detects the movement speed of the iron  10  and sprays steam stored in the steam chamber  18  by way of the steam outlets  14  by causing the first valve  28  to be opened. Conversely, when the iron  10  moves slower than the first predetermined speed, the first valve  28  is moved from the open position to the closed position. 
     As discussed above, in addition to measuring speed of movement, the sensor  40  can also detect and measure tilt angles. Such tilt angle data is provided from the sensor  40  to the controller  34 . In turn, the controller  34  causes the first valve  28  to move between the open and closed positions depending on the detected tilt angle. In one embodiment of the invention, the first valve  28  is closed when a tilt angle of the steam iron  10  is about 90° (e.g., 90°±10°). That is, the user has placed the iron  10  in an upright or erect position, such as that shown in  FIG. 2A . In another embodiment of the invention, the first valve  28  is closed when a tilt angle of the steam iron  10  is greater than about 20° (e.g., 20°±10°), as shown in  FIG. 2D . 
     Referring now to  FIGS. 2A-2D , the operation of the steam iron  10  is shown.  FIG. 2A  shows the steam iron  10  in an upright or erect position. The iron  10  would be in such position, for example, before or after use, or when the user is taking a break or re-positioning the item being ironed. When the iron  10  is in the upright position (i.e., the tilt angle is about 90°, as detected by the sensor  40 ), the first valve  28  is maintained in the closed position. 
       FIGS. 2B and 2C  show the iron  10  in a flat or in-use position (i.e., the tilt angle is close to 0°, as detected by the sensor  40 ). In such case, the sensor  40  also measures the speed at which the iron is being moved, either forward or backward, and can cause steam to be sprayed out of the steam outlets  14 . That is, the tilt angle and speed data are provided from the sensor  40  to the controller  34  and the controller  34  causes the first valve  28  to be opened (or closed as the case may be). 
       FIG. 2D  shows the steam iron  10  being lifted or moved from a relatively flat, in-use position, to an upright position. When the iron  10  is at an angle of greater than about 10°, the controller  34  causes the first valve  28  to be closed. 
     The iron  10  may include additional features. For example, temperature information may be passed from the heating elements  20 ,  22  and  24  to the controller  34  so that optimal temperatures thereof may be maintained. Temperature sensors and their interconnection to a microcontroller are well understood by those of skill in the art. In addition, water and steam level information may be passed to the microcontroller  34  so that liquid may be moved from the water reservoir  16  to the steam chamber  18  whenever the steam chamber  18  is low on steam or needs additional steam to maintain enough pressure to eject steam out the steam ports  14 . 
     As is evident from the foregoing discussion, the present invention provides a steam iron with improved steam flow control. By incorporating a three-axis accelerometer, both motion and tilt angle information can be detected and provided to a controller that regulates the production and flow of steam. For example, when the iron is moved from an upright position to an in-use position, steam production may be commenced and when the iron is moved from the in-use position to the upright position, steam production may be inhibited. Additionally, steam generation and ejection can be based on the speed and direction of movement of the iron when in the in-use position. As will be understood by those of skill in the art, the first and second valves  28  and  32  may be opened and/or closed based on other factors not discussed herein, yet not required for a complete understanding of the present invention. 
     The description of the preferred embodiments of the present invention have been presented for purposes of illustration and description, but are not intended to be exhaustive or to limit the invention to the forms disclosed. It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but covers modifications within the spirit and scope of the present invention as defined by the appended claims.