Abstract:
A spray arm of a dish washer having improved washing efficiency by providing the spray arm to pulsate through utilizing the feeding and draining action of washing water, comprises first and second rotation nozzles oppositely formed in each end of the spray arm; a ball moved by washing water fed into the spray arm and the weight of the ball itself, the ball for closing either one of the first and the second nozzles, and a guide member for guiding the ball to move only in one direction.

Description:
FIELD OF THE INVENTION 
     This invention relates to a spray arm pulsation device of a dish washer, more particularly to a spray arm of a dish washer having improved washing efficiency by providing the spray arm to pulsate through utilizing the feeding and draining action of washing water. 
     BACKGROUND OF THE INVENTION 
     A spray arm 1a of a conventional dishwasher is, as shown in FIGS. 1 and 2, rotatably mounted at the center of a feed water pipe 13 which is installed on the bottom 20 of a dish washer. The spray arm 1a has washing nozzles 10 on upper part thereof for spraying washing water toward dishes, and rotation nozzles 11 for generating rotation force by the reaction of washing water sprayed therefrom. 
     When the feed water is, pressurized by a pump(not shown) and fed through the feed water pipe 13, sprayed from the rotation nozzles 11, the spray arm 1a is rotated by the reaction of the feed water spray from the rotation nozzles 11 only in one direction while washing the dishes by the spraying water from the washing nozzles 10. 
     In another conventional spray arm 16 as shown in FIGS. 3 and 4, when the feed water, pressurized by a pump(not shown), is fed inside of the spray arm 1b, ball 6a in the spray arm 1b, moved by water pressure, close rotation nozzles 4a and 5a alternatively changing the direction of spray resulting in a to change of the direction of rotation of the spray arm. 
     However, the conventional spray arm 1a as shown in FIGS. 1 and 2 described above has low washing efficiency due to the existence of a dead zone of spray developed by the one direction rotation of the spray arm 1a forced by water sprayed from the rotation nozzle 11 provided for producing a rotation force. 
     On the other hand, the conventional spray arm 1b in FIGS. 3 and 4, which has ball 6a in the spray arm 1b, resting in the neutral position before starting, repeating the action of closing either one of the rotation nozzles on feeding of water and returning to the neutral position on stop of the feed of water, also has low washing efficiency because the spray arm 1b can hardly be expected to rotate reversing periodically, as the probability of closing either one of the rotation nozzles 4a and 5a by the ball 6a is half and half resulting in the closing of the rotation nozzles being irregular, contrary to the required sequential closing of the rotation nozzles 4a and 5a by the ball 6a for the periodic reversing of the spray arm 1b. 
     SUMMARY OF THE INVENTION 
     The object of this invention is providing a spray arm of a dish washer having improved washing efficiency by widening the range of the spray of the washing water by causing the spray arm to pulsate, without supply of separate power, through utilizing the pressure of the washing water fed to the spray arm. 
     This and other objects and the features of this invention can be achieved by providing a spray arm pulsation device of a dish washer including first and second nozzles formed in opposite direction at the end of the spray arm for spraying washing water, a ball for closing either one of the first and the second rotation nozzles moved by washing water, and a guide member-for guiding the ball to move only in one direction so that the nozzle spraying washing water can be changed from the first; to the second nozzle to change the direction of rotation of the spray arm. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a conventional spray arm of a dish washer 
     FIG. 2 is a front view of a conventional spray arm of a dish washer. 
     FIG. 3 is a sectional view of a part of another conventional spray arm of a dish washer. 
     FIG. 4 shows 4--4 section of FIG. 3. 
     FIG. 5 is a sectional view of a part of a spray arm of a dish washer in accordance with this invention. 
     FIG. 6 is a perspective view of a guide member of a spray arm of a dish washer in accordance with this invention. 
     FIG. 7 is an enlarged sectional view of part &#34;A&#34; of FIG. 6. 
     FIG. 8 is sectional view of a part of a spray arm of a dish washer in accordance with another embodiment of this invention. 
     FIG. 9 is a cut away perspective view in part of a guide member of a spray arm of a dish washer in accordance with another embodiment of this invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 5 to 7 show a spray arm of a dish washer in accordance with one embodiment of this invention including a guide member 2 formed to have a two level crossing with a step at each end of guide rails 2a, 2b, 2c and 2d, and the guide rails 2a, 2b, 2c and 2d each formed to have a slope ended with a step between them, provided with guard rails 3 at both sides thereof to prevent falling down. 
     In the guide member 2, first and second rotation nozzles 4 and 5 used also as washing water outlets positioned oppositely are provided at the guide rails 3 between the first and the second guide rails 2a and 2b, and the third and the fourth guide rails 2c and 2d connected with the spray arm 1, and a ball 6 made of glass or plastic is on the guide rail 2a, 2b, 2c and 2d for closing the first and the second rotation nozzles 4 and 5 alternatively through moving in one direction along the first, the second, the third and the fourth guide rails 2a, 2b, 2c and 2d forced by washing water and the weight of the ball itself. A recess 7 for the rest of the ball is provided at each entrance of the rotation nozzles 4 and 5. 
     The first guide rail 2a is sloped so that a first end is lower than a second end, the second guide rail 2b is sloped so that a first end connected with the second end of the first guide rail is higher than a second end. The first end of the second guide rail is connected with the first nozzle. The third rail 2c is sloped so that a first end connected with the second end of the second guide rail is lower than a second end, and the fourth guide rail 2d is sloped so that a first end connected with the second end of the third guide rail is higher than a second end. The first end of the fourth guide rail is connected with the second nozzle and the second end is connected with the first end of the first guide rail. 
     Accordingly, the ball 6 is forced to move by the washing water fed to the spray arm 1 from the first guide rail to the second guide rail and from the third guide rail to the fourth guide rail, and the ball 6 moves by its weight from the second guide rail 2b to the third guide rail and from the fourth guide rail to the first guide rail. 
     FIGS. 8 and 9 show another embodiment of this invention including, at the end of the spray arm 1, a guide member 2&#39; having first, second, third and fourth sloped guide surfaces 2&#39;a, 2&#39;b, 2&#39;c and 2&#39;d each separated by independent separation room 2&#39;e with steps at the boundaries of the surfaces and, on the top and the bottom of each side of the guide member 2, oppositely positioned first and second rotation nozzles 4&#39; and 5&#39; used also as washing water outlets are provided on the second and the fourth guide surfaces 2&#39;b and 2&#39;d. 
     On one side of the first and the second rotation nozzles 4&#39; and 5&#39; used also as washing water outlets in the guide member 2&#39;, washing water inlets 8 and 9 are provided in the first and the third sloped guide surfaces 2&#39;a and 2&#39;c for the flow in of the fed washing water, and, on the first, the second, the third and the fourth sloped guide surfaces 2&#39;a, 2&#39;b, 2&#39;c and 2&#39;d of the guide member 2&#39;, a ball 6 for alternative closing of the first and the second rotation nozzles 4&#39; and 5&#39; through moving in one direction along the first, the second, the third and the fourth sloped guide surfaces 2&#39;a, 2&#39;b, 2&#39;c and 2&#39;d forced by washing water flowing in through the washing water inlets 8 and 9, and by the weight of the ball itself. 
     The first sloped guide surface 2&#39;a is sloped so that one side is lower than an opposite side. A washing water inlet 8 is in the wall of the one side. The third sloped guide surface 2&#39;c is sloped so that one side is lower than an opposite side. A washing water inlet 9 is in the wall of the one side. The second sloped guide surface 2&#39;b is connected with the first rotation nozzle, and has one side which is in contact with the opposite side of the first sloped guide surface, and is formed to have a slope higher than the third sloped guide surface. The fourth sloped guide surface 2&#39;d is connected with the second rotation nozzle, and has one side which is in contact with the opposite side of the third sloped guide surface, and is formed to have a slope higher than the first sloped guide surface. 
     The spray arm in accordance with one embodiment of this invention, as shown in FIGS. 5 to 7, rotates in a clockwise direction because the ball 6 moves along the first sloped guide rail 2a forced by the washing water to close the first rotation nozzle 4 which is used also as a washing water outlet, this results in the washing water being sprayed through the second rotation nozzle 5. The water which is pressurized by a pump (not shown) flows into the spray arm 1 through a feed water pipe. Because the ball 6 has a higher specific weight than water, the ball 6 rests at one end of the first guide rail 2a in the guide member 2 mounted in the spray arm 1 of a dish washer. 
     Thereafter, when the feed of washing water to the spray arm 1 is stopped, the ball 6, which is closing the first rotation nozzle 4, is unable to move toward the first guide rail 2a due to the step 2a&#39; and this moves down to the third guide rail 2c through the second sloped guide rail 2b by the weight of the ball itself. 
     At this time, when washing water is again fed to the spray arm 1, the ball 6 resting at one end of the third guide rail 2c, is unable to move over toward the second guide rail due to the step 2b&#39; of the second guide rail, and thus moves along the third guide rail 2c forced by the water feed and closes the second rotation nozzle 5 so that the washing water is sprayed through the first nozzle 4 to force to rotate the spray arm 1 in anti-clock wise direction. 
     Then, when the water feed to the spray arm 1 is stopped, the ball 6, as shown in FIG. 7, is unable to move toward the third guide rail 2c due to the step 2c&#39; at the third guide rail 2c, and thus moves down along the fourth sloped guide rail 2d to return to one end of the first guide rail 2a by the weight of the ball itself, which ball 6, then, when the water feed to the spray arm 1 is started again, is unable to move toward the fourth rail 2d due to the step 2d&#39; at the fourth guide rail 2d, and thus moves up to the first guide rail forced by the water feed. 
     Thus, the ball 6 repeats the aforementioned processes, causing the spray arm 1 to pulsate. 
     In the meantime, as guard rail 3 is formed on both sides of the first, the second, the third and the fourth guide rails 2a, 2b, 2c and 2d of the guide member 2, the ball 6 is prevented from falling down, and as recesses are formed on the bottom of the first and the second, and the third and the fourth guide rail 2a, 2b, 2c and 2d at the entrances to the first and the second rotation nozzles 4 and 5, the ball 6 can stay stable without any movement during the closure of the first and the second rotation nozzles 4 and 5. 
     On the other hand, when the washing water fed to the spray arm enters into the separated room 2&#39;e through the washing water inlets 8 and 9, as shown in FIGS, 8 and 9, while the Washing water inlet 8 in the first sloped guide surface 2&#39;a in guide member 2&#39; in the spray arm 1 of the dish washer, is kept closed by the ball 6, the ball 6 is pushed toward the second sloped guide surface 2&#39;b over the step of the first sloped guide surface 2&#39;a resulting in the closure of the first rotation nozzle 4&#39; used also as a washing water outlet so that the spray arm rotates in clockwise direction by the washing water sprayed from the second rotation nozzle 5&#39; in the fourth sloped guide surface 2&#39;d of the guide member 2&#39;. When the water feed to the spray arm 1 is stopped, the ball 6 is unable to move toward the first sloped guide surface 2&#39;a due to the step 2&#39;a&#39; of the first sloped guide surface 2&#39;a, and thus moves down to the third sloped guide surface 2&#39;c from the second sloped guide surface 2&#39;b due to the slope of the second sloped guide surface 2&#39;b by the weight of the ball itself. 
     When the water is again fed to the spray arm 1 and into the separation room 2&#39;e through the washing water inlets 8 and 9 in the first and the third sloped guide surfaces 2&#39;a and 2&#39;c of the guide member 2&#39; the spray arm 1 rotates in a counter clockwise direction because the ball 6, which was closing the washing water inlet 9 of the third sloped guide surface 2&#39;c, closes the second rotation nozzle 5&#39; used also as a washing water outlet in the fourth sloped guide surface 2&#39;d because the ball is pushed over the step 2&#39;c&#39; of the third sloped guide surface 2&#39;c toward the fourth sloped guide surface 2&#39;d by the force of the water feed resulting in the water feed being sprayed from the first rotation nozzle 4&#39;. 
     When the water feed to the spray arm 1 is stopped, the ball 6, as shown in FIG. 9, is unable to move to the sloped third guide surface 2&#39;c due to the step 2&#39;c&#39; of the third sloped guide surface 2&#39;c, but moves down to the first sloped guide surface 2&#39;a along the fourth sloped guide surface 2&#39;d by the weight of the ball itself. Thus, the spray arm 1 pulsates in accordance with the aforementioned operation sequence. 
     As seen from aforementioned description, this invention can improve the washing efficiency of a dish washer by providing a guide member in a spray arm including a ball having higher specific gravity than the washing water closing the first and the second rotation nozzles alternatively, without supply of separate power, moving in one direction forced by the water feed to the spray arm and the weight of the ball itself causing the spray arm to pulsate to widen the range of the spray of the spray arm. 
     Although the invention has been described in conjunction with specific embodiments, it is evident that many alternatives and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the invention is intended to embrace all of the alternatives and variations that fall within the spirit and scope of the appended claims.