Dishwasher rack supporting and adjusting apparatus
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a dishrack supporting and adjusting apparatus for a dishwasher in which improved means are provided for supporting each side of the dishrack and for adjusting the support relative to the dishrack to accommodate articles of varying heights in the dishwasher. 
     2. Description of the Prior Art 
     In preparing the application, the following U.S. patents were considered: U.S. Pat. Nos. 3,269,548; 3,472,573; 3,614,187; 3,734,589; 3,768,883; 3,809,450; 3,809,451, and 3,822,085. These disclose various adjusting mechanisms for adjusting the position of a dishrack but none of them discloses the invention as claimed herein. 
     SUMMARY OF THE INVENTION 
     The dishrack supporting and adjusting apparatus of this invention includes an enclosing housing on each side of the rack formed of separable parts embracing the sides of the rack with each housing mounting a pair of arms extending forwardly and rearwardly of the corresponding side of the rack and close to the side and each carrying a supporting wheel, or roller, so that the two wheels on each side of the rack are in tandem. In order to provide for adjusting the position of the wheels, the ends of the arms within the housing are formed as arcuate worm wheel sectors each concentric with the fulcrum axis of its arm and with the two sector gears on each side of the dishrack being spaced apart a distance sufficient to provide for a worm gear located between the sectors and engaging gear teeth on both. Each worm gear has an end externally of the housing and provided with a hand engageable knob for rotating the worm and thereby moving the sector gears to move arcuately the arms simultaneously on each side about their fulcrums. 
     The parts are so proportioned that the rollers are preferably horizontally aligned in all adjusted positions of the arms on a side of the rack in the preferred construction and in an especially preferred construction, all of the arms, all of the sector gears, all of the worm gears and all of the corresponding housing parts are structurally identical. 
     In an especially preferred apparatus, each sector gear includes a stop member with these stop members engaging the worm gear at the ends of the desired range of movement of the arms so as to determine this range of movement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein: 
     FIG. 1 is a fragmentary side elevational view partially broken away for clarity of illustration illustrating a dishwasher with the dishrack in an extended position and including supporting apparatus embodying the invention; 
     FIG. 2 is a view similar to FIG. 1 but showing the supporting arms and wheels in the opposite adjusted position from that shown in FIG. 1; 
     FIG. 3 is an enlarged fragmentary sectional view illustrating a portion of the structure in the lowermost adjusted arrangement of the dishrack, with parts broken away for clarity of illustration; 
     FIG. 4 is a vertical sectional view taken substantially along the line 4--4 of FIG. 3; 
     FIG. 5 is an enlarged fragmentary sectional view of the structure of FIG. 3 in the uppermost adjusted arrangement of the dishrack; and 
     FIG. 6 is a fragmentary front elevation of the dishwasher with the dishrack in a canted disposition to accommodate a tall article on the lower dishrack at one side thereof. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the embodiment illustrated in the drawings, there is provided a dishwasher 10 including an opening 11 at the front normally closed by a door (not shown) that provides access to a tub 12 on each side of which there is provided a supporting guide track 13 that is movably supported as on pairs of upper and lower side rollers 14 mounted on the tub sidewall so that the track can be projected from the tub 12 for loading and unloading a dishrack 15 when the dishrack is in the projected position shown in FIG. 1. 
     The dishrack 15, in the illustrated embodiment, comprises spaced wires including wires 16 and a top wire 17. The wires 16 and 17 define a side 18 of the dishrack and each side 18 has mounted thereon a housing 19 comprising two separable parts 20 and 21. 
     Extending forwardly and rearwardly of each housing 19 are a pair of substantially coplanar arms 22 and 23, each carrying on its extended end a roller, or wheel, 24. The result is that the arms 22 and 23 and the wheels 24 are all substantially coplanar and they, with the corresponding housing 19, are located against the side 18 of the dishrack. Each pair of wheels 24 on each side of the dishrack is in tandem, i.e., one behind the other, and maintained supported on its associated track 13 in all positions of the rack. The wheels 24 roll within their guide track 13 in the customary manner so that the four side wheels 24 support the rack for forward and rearward movement and also, by engaging upper and lower flanges 25 of the tracks 13, support the rack against vertical dislodgment and tipping. 
     Each arm 22 and 23 is mounted for rotation about a fulcrum 27 so as to be arcuately movable about an axis 26 that is concentric with its fulcrum 27. Each arm 22 and 23 has the end that is within the housing 19 comprising a circular flange 28 that is generally concentric with the axis 26 and on an outer peripheral surface of the inner side of this flange, there is integrally formed a worm wheel sector gear 29. 
     These sector gears are spaced apart, as shown in FIG. 3, a distance substantially equal to the thickness of a worm gear 31. The helical teeth of these worm gears 31 engage the teeth of their sector gears 29 and 30 and each worm gear extends upwardly from its corresponding housing 19 to provide an external stem 32 on the upper end of which is mounted a knob 33 that can be rotated by hand to move both the sector gears 29 and 30 simultaneously and thereby simultaneously adjust the positions of the arms 22 and 23 and of the supporting wheels 24. The two extreme positions of the arms and the wheels are illustrated in FIGS. 1 and 2. 
     In the illustrated embodiment, each arm 22 and 23 may be constructed integrally with its corresponding sector gear and these integral parts may be substantially identical. These same parts are also identical to those in the opposite supporting apparatus (not shown) on the opposite side of the dishrack. 
     As can be seen in FIGS. 3 and 4, the two separable parts 20 and 21 of the housing 19 not only enclose the gears and the inner ends of the arms 22 and 23, but also embrace the corresponding side wires 16 so as to support the housing 19 and, thus, the supporting wheels 24. In this embodiment, the arms and the gears are supported primarily by the one housing part 20 while the wires 16 are located in grooves 34 within the other housing part 21 with the result that when the housing parts 20 and 21 are assembled, as shown in FIG. 4, the grooves 34 and, thus, the adjacent portions of wires 16 are enclosed. 
     The adjustable rack supporting apparatus of this invention operates as follows. Each knob 33 on each side 18 of the dishrack 15 is independently rotatable so as to rotate the corresponding worm gear 31 and move arcuately and simultaneously the corresponding pair of sector gears 29 and 30. This adjusts the position of the arms 22 and 23 in a vertical plane thereby adjusting the height of each pair of supporting wheels 24 with respect to the rack simultaneously so as to maintain the same relative positions each to the other. Since each housing 19 is fixed to dishrack 15, the positions of the supporting wheels 24 with respect to their corresponding housing 19 will, because of their engagement with the side guide tracks 13, determine the vertical position of the dishrack 15. Then, when any adjustments are required as for accommodating dishes or similar articles of different heights within the dishwasher tub, the vertical position of the dishrack 15 is easily changed by turning the two adjusting knobs 33. 
     The supporting arm 23, being movable to adjusted position by rotating the corresponding worm gear 31, means that the rollers 24 on each side of the rack are independently adjustable to an infinite number of vertical positions within the adjustment range. These arms on each side of the dishrack are movable through a range of movement and the extremes of this range of movement are determined by a pair of stop portions 35 and 36 comprising projections each adjacent one end of the sector gears 29 and 30 with the two stop portions or members 35 and 36 being located opposite to each other. By placing the stop members 35 and 36 at the end of the toothed segments of the cooperating sector gears 29 and 30, the stop member 35 engages a surface 31b at the upper end of the worm gear 31 in the extreme downward position of the dishrack, as shown in FIG. 3, while the other stop member 36 engages a surface 31a at the lower end of worm gear 31 at the extreme of the range of upward adjustment of the dishrack, as shown in FIG. 5. 
     As can be seen, the supporting and adjusting mechanism is quite compact and thin so that each can be positioned adjacent to one side of the dishrack as shown and will not interfere with the loading or unloading of the rack or servicing of the dishwasher. In addition, the entire unit is quite inexpensive as it can be made of molded plastic, such as polypropylene, and each arm 23, roller 24 support, sector gear 30, and stop 36, for example, can be made from one integral molding. Similarly, each worm gear 31, stem 32, and knob, or handle, 33 can be made from a one-piece molding. In addition, the one housing part 20 not only serves as a support for the operating parts of the apparatus, but also as a closure that cooperates with the other housing part 21 to embrace portions of the corresponding side wires 16 so as to mount the entire side apparatus on these wires and, thus, on the side of the dishrack. 
     As can be further seen, one important feature of the adjustable dishrack supporting structure herein is that the rack is, at all times, completely supported during the adjustment process. Thus, the rack cannot be dropped or shaken inadvertently by the operator during the adjustment, and the contents of the rack will not be subject to damage from jarring as the result of abrupt movements. Movement of the rack between extremes of its travel is gradual and relatively uniform in moderate increments as the adjustment knob is manually turned by the operator. 
     With reference to FIG. 6, another highly desirable feature of the present invention is the independent adjustability of the elevation of the respective sides of the dishrack by means of the improved supporting and adjusting mechanism. As is conventional in such dishwashers, in addition to the upper dishrack 15, as discussed above, a main, or lower, dishrack 37 may be provided in the lower portion of the tub in the conventional manner. The lower dishrack is adapted to carry larger items, such as dinner plates 38 and cooking utensils, such as a cookie tin 39, as illustrated in FIG. 6. As shown therein, where the elements to be washed, such as cookie tin 39, extend upwardly from the lower rack 37 to beyond the lower portion of the upper rack 15 when the upper rack is in its lowermost position, the portion of the rack which is in overlying relationship to the relatively tall elements may be raised independently of the other portions of the rack, thereby accommodating the tall elements carried by the lower rack while yet permitting relatively tall elements, such as bowl 40, to be carried on the upper rack 15 at portions thereof remote from the upwardly adjusted portion. Thus, the present invention provides an improved adjustability in the positioning of the upper rack to conform the disposition thereof more accurately to the individual loadings of the dishwasher. 
     By virtue of the use of the worm gear, the adjusted position of the upper dishrack is effectively releasably locked. Additionally, the amount of canting of the upper dishrack about the fore-and-aft centerline thereof is limited by the stop members 35 and 36 to a preselected maximum canting in either direction about the centerline. 
     While a highly desirable feature of the present invention is the permissible canting to accommodate tall articles at one side of the dishwasher, as will be obvious to those skilled in the art, the present invention further permits distribution of such articles on the lower dishrack by permitting the elevation of the entire upper dishrack to an upper canted, or horizontal disposition as required by the article loading.