Abstract:
A filter cone fixed to the bottom of a washing machine basket includes a plurality of closely spaced rigid teeth in a circumferential row extending outwardly and upwardly to divide the tub into first and second chambers for filtering laundry liquid during a washing cycle and for preventing sediment and debris from returning into the basket during a direct-into-spin portion of the wash cycle. The reverse flow of water through the filter teeth during the drain portion of the washing cycle effects self-cleaning of the teeth.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to automatic washing machines of the vertical axis type and more particularly to a filter system for such automatic washing machines. 
     2. Description of the Prior Art 
     U.S. Pat. No. 4,075,876 describes the problem occurring during the agitation and scrubbing of clothing articles in an automatic washing machine when particles of lint are developed from the fabrics being cleaned and become suspended in the laundry liquid. Such lint particles must be removed from the laundry liquid during the washing cycle, otherwise they will be redeposited on the articles being laundered in later steps of the washing program. 
     It is also known that sediment and debris particles are also removed from clothing articles during the agitation and scrubbing of the clothing articles. Such sediment and debris particles tend to gravitate to the bottom of the washing basket or washing tub. 
     In one form of automatic washer manufactured and sold by applicants&#39; assignee, the motor in the washing machine is reversed after the agitation cycle and the drain pump is actuated to drain the basket and tub of laundry liquid. At the same time the basket is driven in rotation for the spin cycle or centrifuging mode. Such a cycle sequence is sometimes referred to as a direct-into-spin system because the basket begins its spin cycle before the washing liquid has been drained therefrom. 
     Such a direct-into-spin system can cause a pressure gradient forcing the laundry liquid from the tub through openings in the bottom of the basket and outwardly through the clothes, thus distributing sediment and debris particles that have settled within the tub on the clean clothes. 
     U.S. Pat. No. 3,352,130 discloses a filtering arrangement in an automatic washer wherein liquid is pumped from a tub to a closed receptacle or basket by the pumping action of an agitator oscillating within the basket during the washing cycle. Liquid enters the basket from the tub through openings in the bottom of the basket, and liquid circulates from the basket to the tub through perforations in the basket side wall. 
     Filter elements mounted in the openings in the bottom of the basket collect the lint carried by liquid passing through the openings, and the lint thus collected is thrown off and carried to drain when the basket spins during the centrifuging mode of machine operation. A row of holes is provided in the bottom wall of the basket for permitting sand and other sediment to pass from the basket to the tub. This row of holes formed in the bottom wall of the basket permits unfiltered communication between the basket and the tub. Operating such a structure with a direct-into-spin cycle would allow the deposited sand and sediment particles to reenter the basket area through these holes to be redeposited on the laundered articles. 
     SUMMARY OF THE INVENTION 
     A truncated filter cone constructed of a rigid material such as polypropylene is fastened beneath the bottom of a clothes basket, by means of a plurality of fingers at the top of the cone having buttons on the ends thereof being received in holes formed in the hollow center post portion of the basket. The filter cone comprises a generally truncated conical shape which is positioned adjacent the bottom wall of the basket near the upper end of the cone and is spaced from the bottom wall of the basket at the lower end of the cone. The lower end or periphery of the cone has upwardly and outwardly extending rigid teeth spaced closely subjacent the bottom wall of the basket along a generally circular line. 
     As a pumping agitator mounted in the basket draws liquid along a path radially inward from the periphery of the tub sump beneath the basket, lint carried by the liquid is trapped on and between the teeth of the filter cone. The liquid is drawn through apertures in the bottom wall of the basket and into the basket through the agitator. The liquid then flows outwardly through a side wall in the basket and downwardly toward the sump to repeat the cycle. 
     During the direct-into-spin portion of the cycle, a pressure differential is established by the spinning of the basket, tending to cause laundry liquid to flow back into the basket through the openings in the bottom wall. During this portion of the cycle, the rotating rigid filter teeth provide a pumping action to oppose this flow and along with the conical shape of the filter prevent sand or sediment from returning to the basket to be deposited on the clothing. 
     As the water level within the tub is decreased by the drain pump the pumping action of the filter teeth causes water flow outwardly from the basket through the openings in the bottom of the basket, thereby automatically cleaning the filter teeth. The lint then moves to drain from the tub along with the laundry liquid, thus automatically effecting a cleaning of the filter without manual intervention. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an automatic washing machine with parts broken away to show the mechanical parts of a washing machine including a tub with a vertical agitator and embodying the principles of the present invention. 
     FIG. 2 is a fragmentary cross sectional view with parts shown in elevation taken generally along line II--II of FIG. 1. 
     FIG. 3 is a cross sectional view taken generally along the line III--III of FIG. 2 showing the plan view of a filter cone. 
     FIG. 4 is a partial side elevational view of the filter cone taken generally along the lines IV--IV of FIG. 3. 
     FIG. 5 is a cross sectional view of the filter cone taken in the plane of line V--V of FIG. 3. 
     FIG. 6 is a plan view of a filter cone embodying optional features of construction. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1 a washing machine is generally shown at 10 as having a tub 12 and a vertical agitator 14 therein, a water supply (not shown), a power supply (not shown), an electrically driven motor 16 operably connected via a transmission 18 to the agitator 14, and controls 20 including a pre-settable sequential control means 22 for use in selectively operating the washing machine 10 through a selected programmed sequence of washing, rinsing and spinning or extracting steps. 
     FIG. 2 shows a cross sectional view of the interior of the tub 12 which shows a concentrically mounted perforate basket 24 having a side wall 26 and a bottom wall 28. The bottom wall slopes upwardly from the outer circumference at the side wall 26 to a center post portion 29. A plurality of openings 30 are formed in the side wall 26 and a series of openings 32 are formed in the bottom wall 28 adjacent the center post portion 29 thereof. 
     The tub 12 is comprised of an imperforate side wall 36 and a generally imperforate bottom wall 38 having a single drain opening 40 formed in a sump portion 42 of the bottom wall 38. The agitator 14 has a plurality of vanes 44 extending radially from a central vertical portion 46 thereof. The vanes 44 may have flexibility if so desired. The agitator vertical portion 46 is concentrically mounted about the basket center post 29 and is driven by an agitator drive shaft 47 by means of a conventional spline connection (not shown). 
     A skirt portion 48 of the agitator 14 is provided below the flexible vanes 44 and includes a pumping means 50 comprising radial vanes located beneath the skirt portion 48 by which the agitator pumping means 50 pumps laundry liquid outwardly upon each oscillation of the agitator 14. The openings 32 in the bottom wall 28 of the basket are located below and near a radially inward end 52 of the pumping means 50 of the agitator such that laundry liquid is drawn up through openings 32 and is caused to flow radially outwardly through pumping means 50 by the centrifugal force imparted by the oscillating agitator 14. 
     Liquid flows out from under the skirt 48 as at arrow 54 to enter the basket 24 and then flows outwardly through the holes 30 in the basket side wall 26 as at arrows 56 and downwardly past the sump portion 42 of the tub radially inwardly along the underside of the basket bottom wall 28 as at arrows 58 to return to the interior of the basket 24 through openings 32. As the laundry liquid passes in this liquid circuit, sand and other heavy dirt particles or debris are generally deposited along the sump portion 42 of the tub 12. 
     A conical filter means or element 60 is provided between the sloping bottom wall 28 of the basket 24 and the bottom wall 38 of the tub 12. The cross sectional shape of the filter element is best seen in FIG. 5. The filter element 60 is attached to the basket 24 by means of a plurality of fingers 62 which extend radially upwardly at a top end 63 of a conical wall 64 which forms the main body of the filter element 60. The fingers 62 have radially protruding buttons 65 formed at a top end thereof which are received through complementary shaped openings 66 in the basket center post 29 as best seen in FIG. 2. 
     A groove 68 is formed on the interior side wall 70 of the buttons 65 to receive a retaining ring 72 which urges the fingers 62 and buttons 64 in a radially outward direction to retain buttons 65 in the openings 66 of the center post 29. The finger portions 62 of the cone filter element 60 merge with the conical wall 64 in a generally curved manner as at 74 where the conical wall 64 is in close proximity to the bottom wall 28 of the basket 24. 
     As the conical wall 64 progresses radially outwardly from merger point 74, it is sloped downwardly at a greater angle than the slope of the bottom wall 28 of the basket 24 such that a lower end 76 of the conical wall 64 is spaced from the bottom wall 28 of the basket 24. To maintain this spaced relationship, a plurality of steps 78 are provided in the conical wall 64 to abut against the bottom wall 28 of the basket 24. 
     A plurality of teeth 80 are provided at the lower end 76 of the conical wall 64 which extend radially outwardly to a position closely subjacent the bottom wall 28 of the basket 24 leaving an opening 81 there between. In accordance with this invention, the teeth 80 are made rigid. Thus, the teeth 80 form a stable barrier between a first tub region or chamber 82 located radially inward of the teeth 80 and above the conical wall 64 and a second tub region or chamber 84 radially outward of the teeth 80. The first tub region or chamber 82 comprises an annular passageway between the second tub region or chamber 84 and the openings 32 leading into the basket 24 which is bounded on an upper side by the basket bottom wall 28 and on the lower side by the conical wall 64. 
     When the agitator 14 oscillates, the pumping means 50 pumps liquid radially outwardly on the interior of the basket 24 along the bottom wall 28 of the basket. The liquid then flows upwardly through the basket and out through the openings 30 in the side wall 26 of the basket 24 into the second tub chamber or portion 84. The liquid passes the sump portion 42 and then flows between and over the filter teeth 80 into the first tub portion or chamber 82 and back through the openings 32 in the bottom wall 28 of the basket 24 to repeat the cycle. Any lint suspended in the liquid is retained against an outside surface 86 of the teeth preventing the lint from being redeposited on the laundered articles. 
     When the washing cycle progresses into a direct-into-spin portion of the cycle spinning the basket 24 and thus the filter element 60, a pressure gradient, as shown by line 87 in FIG. 2, results in the liquid wherein the pressure along the tub bottom wall 38 is greatest at the side wall 36 and lowest adjacent the agitator center post 14. This pressure difference or gradient would normally cause a flow of water radially inwardly along the tub bottom wall 38 tending to result in a return flow into the basket 24 through openings 32. The rotating rigid filter teeth 80, however, provide a pumping action opposing flow from the tub through the teeth and inwardly through openings 32 into the basket. There is thus no flow into the basket through openings 32. As the water level in the basket decreases, the pumping action of the teeth 80 causes an increased flow outwardly from the basket, through openings 32 and teeth 80 into the tub 12. Thus, the rotating rigid filter teeth 80 and the conical wall 64 provide a barrier which prevents the sediment and debris which has accumulated in the sump portion 42 from returning to the basket 24. 
     When the water level in the tub 12 is sufficiently decreased by passage of liquid through the drain 40, the pumping action of the filter increases due to the reduced pressure at side wall 36. The flow of water increases through the holes 32 in the bottom wall 28 of the basket 24, flowing radially outwardly between the teeth 80, to thereby aid the centrifugal force created by the rotation of the filter element 60 in cleaning the lint and debris from the outer surface 86 of the teeth 80. The annular opening 81 allows any lint or debris in region 82 to pass outwardly into region 84. Such lint and debris in region 84 is carried by the draining liquid through the drain 40 with the waste water. 
     As seen in FIG. 3, the teeth 80 may be formed in a direction extending radially outwardly from the agitator drive shaft 47. The steps 78 are provided at sufficiently spaced apart locations to allow for unimpeded flow along the conical wall 64 as the wash liquid travels between the teeth 80 and the openings 32 in the basket bottom wall 28. 
     A side elevational view of a portion of the filter cone 60 is shown in FIG. 4 showing the relationship between the filter teeth 80 and front surfaces 86 thereof, the lower end 76 of the cone wall 64 and the steps 78. 
     An alternative embodiment of the invention is shown in FIG. 6 wherein an alternative cone filter element 600 is shown having teeth 800 formed at an angle A with respect to radial lines projecting from a conical center 810. 
     Although a filter cone having fingers of a configuration like those shown in FIGS. 3 and 6 is preferred, it will be understood that many different forms of filtering barriers and many different configurations of lint collecting teeth could be effectively utilized within the scope of our invention. While these and other various modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.