Patent Abstract:
A washing fluid container of substantially cylindrical configuration having at least one open end closed by a cover provided with an integrally formed air trap penetrating the cover at an acute angle with a first housing section extending at an acute angle upwardly of the surface of the cover outside of the container and a second housing section extending at an acute angle downwardly of the surface of the cover inside of the cover, the second housing section being adapted to receive washing fluid therein and the first housing section being provided with means responsive to washing fluid in the second housing section.

Full Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention, in general, relates to a plastic washing fluid container, hereafter sometimes referred to as a tub, for a washing machine and, more particularly, to a tub surrounding a cylindrical drum each end of which is provided with a closure cap at least one of which has an air trap for measuring the washing fluid level and which at its lower and upper ends is respectively provided with an opening and a nipple for receiving a hose.  
         [0003]     2. The Prior Art  
         [0004]     Such well-know air traps are used for measuring the level of washing fluid which at different operational cycles of the washing machine is either plain water or water with a detergent dissolved therein, in a washing machine drum. As washing fluid rises within the air trap it causes the air entrapped therein to be compressed. The pressure of the compressed air is a measure of the level of washing fluid. Thus, German patent specification No.: DE 196 46 440 C2 to Thier et al. discloses an air trap at one of the caps of the washing fluid tub. The air trap disclosed by the German patent specification is a component mounted on the cap at a certain area thereof and requires an appropriate additional gasket or seal.  
         [0005]     U.S. Pat. No. 5,115,651 to Nukaga et al. discloses an air trap formed on the cap of the washing fluid tub. In this case the housing is arranged at the exterior of the washing fluid tub and, therefore, necessitates additional means for connection with the internal chamber of the washing fluid tub.  
         [0006]     European patent specification No.: 0,247,651 A1 to Grabarcsyk discloses an air trap mounted on the cylindrical container surrounding the drum, and U.S. Pat. No. 4,423,607 to Munimi discloses an air trap mounted on the washing fluid tub.  
         [0007]     The disadvantage inherent in the devices of the mentioned prior art is not only that on the one hand the air traps are mounted as a separate components on the cap of the washing fluid container involving, on the other hand and particularly in the case of the air trap being mounted on the cylindrical drum, significant complexity if layout, design or geometry of detecting the air within the trap requires modification. In such cases it would be necessary to provide a complex injection molding tool to form the hollow body of the air trap.  
       OBJECT OF THE INVENTION  
       [0008]     It is thus an object of the invention so to improve a plastic washing fluid container and, more particularly, the cap of such a container that the air trap may be structured at the cap of the washing fluid container such that it may be integrally formed by an injection molding tool.  
         [0009]     In the accomplishment of these and other objects the invention provides for an air trap in a plastic washing fluid container of the kind referred to supra in which the air trap with its downwardly open housing and integral opening nipple is integrally formed in the wall of the washing fluid container cap in penetrating relationship therewith.  
         [0010]     The advantages resulting from the arrangement in accordance with the invention are not least that the downwardly open housing with its attached opening nipple is an integral component of the cap of the washing fluid tub in penetrating relationship therewith such that the latter and the air trap are of unitary structure. This arrangement allows the air trap housing to be integrated into an injection molding tool so that both the air trap and the washing fluid container cap may be molded in a single operation. The result is an air trap which is fully integrated in the cap of the washing fluid container and which avoids the need for additional caps and seals or gaskets in the cap of the washing fluid container. In this manner the complexity of any alteration of the air trap in terms of tools otherwise required is minimized or at least reduced, because forming the hollow body of the air trap requires but one core in the injection molding tool for the cap of the washing fluid container. Moreover, the volume and the cross-section of the opening may be adjusted to existing air traps and significant changes or conversion procedures can be avoided.  
         [0011]     In order to structure the injection molding tool in an advantageous manner as regards the directions of discharge from the mold, the housing with its opening nipple occupies a partial section of the outer wall surface of the washing fluid container cap with the opening nipple being formed to extend upwardly at an acute angle relative to the outer wall surface of the washing fluid container cap. Accordingly, the opening nipple is not only of a compact structure but it also is easily accessible for attaching a hose. As regards the inner wall surface, the housing is structured such that the housing of the air trap and its downwardly open section occupy a partial section of the inner wall surface of the washing fluid container cap, with the section of the opening being preferably also formed at a downwardly directed acute angle at the surface of the inner wall. In this manner it is possible to provide two mold discharge directions, one being disposed laterally and the other one in the direction of the angle of the air trap.  
         [0012]     In an advantageous embodiment of the invention the partial section of the surface of the inner wall forming the housing of the air trap is offset in a step-like manner in order to enlarge the cross-section of the opening. Preferably, the step is inclined which advantageously affects the mold discharge process. The walls forming the housing are disposed parallel to each other which also affects the mold discharge process in an advantageous manner.  
         [0013]     In accordance with another embodiment, more particularly in an upper section of the housing, the opening nipple for the hose is formed to extend into the interior of the housing. As a result of this structure, it is possible to operate with only one core in the mold for integrating the housing of the air trap. For securely attaching the hose to the downwardly extending opening nipple, the sleeve section of the nipple is provided with a collar or shoulder for arresting the hose.  
         [0014]     In a useful embodiment the housing of the air trap is formed of a lower housing section and an upper housing section with the downwardly open lower housing section being integrally formed in, and penetrating through, the wall of the washing fluid container cap. The internal chamber of the air trap is thus accessible from the exterior because the upper housing section is mounted for movement relative to the lower housing section at the outer surface of the washing fluid container cap. Accordingly, the interior of the housing of the air trap is easily accessible for cleaning.  
         [0015]     Advantageously, the upper housing section is integrally connected to the lower housing section by means of a hinge of flexible film or foil which makes possible the fabrication of both housing sections in one injection molding tool. In such an arrangement the upper housing section is pivotally connected to the lower housing section by the foil hinge so that the cap of the washing fluid container and the two housing sections may be molded in one piece. This yields two advantages: The air trap is integrally formed in the cap of the washing fluid container and as a result of the foil-hinge connection the interior of the air trap is rendered accessible.  
         [0016]     In order to achieve an efficient integration of the air trap in the cap of the washing fluid container, the lower housing section occupies a partial section of the surface of the outer wall of the cap of the washing fluid container with the partial section being advantageously formed to extend upwardly from the outer surface at an acute angle in the manner of a wedge resulting, relative to the outer surface, in an opening of rectangular or square cross-section. However, to improve the sealing properties between the upper housing section and the lower housing section it may be useful so to shape the partial section formed in the wall to yield an opening of oval, elliptical or circular cross-section.  
         [0017]     The downwardly open section of the lower housing section is offset in a step-like manner for enlarging the opening area, i.e. the water-inlet area. The step is inclined which facilitates its configuration. The lateral walls forming the housing are disposed parallel to each other which results in a rectangular channel-shaped housing, i.e. the internal chamber has a rectangular profile. In order to seal the upper section with respect to the lower section, the upper section is provided with a circumscribing groove for receiving a gasket. For opening or closing the upper housing section its outer wall is provided with lugs for securing it in a snap-like manner. Outwardly extending ribs are formed in the lateral walls of the lower housing section which occupies a partial section of the surface of the inner wall of the washing fluid container cap. Within the ribs there are provided bores or openings for receiving the lugs.  
         [0018]     To provide for an easy or snap closure, the edges of the ribs are beveled or slanted which results in an incline. Thus, if the upper housing section is pivoted, the lugs thereof will initially engage the inclines, and the inclines will cause the ribs to be spread apart so that the lugs can more easily move relative to the bores. 
     
    
     DESCRIPTION OF THE SEVERAL DRAWINGS  
       [0019]     The novel features which are considered to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, in respect of its structure, construction and lay-out as well as its manufacturing techniques, together with other advantages and objects thereof, will be best understood from the following description of preferred embodiments when read in connection with the appended drawings, in which:  
         [0020]      FIG. 1 : is a sectional presentation of a first embodiment of an air trap inserted in a cap of a washing fluid container;  
         [0021]      FIG. 2 : is a sectional presentation of a second embodiment of an air trap inserted in a cap of a washing fluid container;  
         [0022]      FIG. 3 : is a detailed view of an opening nipple of the embodiment shown in  FIG. 2 ;  
         [0023]      FIG. 4 ,  5 : depict an embodiment of an inserted air trap with a removable upper section; and  
         [0024]      FIG. 6 : is a schematic presentation of a washing machine. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]      FIG. 6  is a schematic lateral sectional view showing a washing machine  30  provided with a washing fluid container  1 . The washing fluid container  1  consist of a cylindrically structured receptacle  2  which surrounds a drum  31 . The cylindrical receptacle  2  is closed by at least one front wall or cap  3 .  
         [0026]      FIGS. 1 and 2  depict a section of a washing fluid container  1  made of plastic. At each end of the receptacle  2  there is provided a structured washing fluid container cap  3 . As may be seen in  FIGS. 1 and 2 , one of the washing fluid container caps  3 , which may have been retrofitted to the receptacle  2 , is provided with an air trap  4  for measuring the level of washing fluid. The air trap  4  has a housing  5  which opens in a downward direction and which at its upper end is provided with an opening nipple  6  for a measuring hose (not shown). As will be understood by those skilled in the art and as indicated supra, the hose is connected to a gage (not shown) or the like for deriving a measure of the level of washing fluid in the container as a function of the pneumatic pressure within the air trap  4 .  
         [0027]     Looking at both  FIGS. 1 and 2 , it will become apparent that the downwardly open housing  5  and its integral opening nipple  6  are fitted into the washing fluid container cap  3 , i.e. the cap  3  and the air trap  4  are fabricated as a one-piece molded component. In the embodiment shown, it is of particular advantage that the fully integrated air trap  4  can be fabricated by a single mold tool with only one additional core being required for molding the section of the hollow body of the housing  5 . The corresponding mold discharge directions have been indicated by arrows  13 ,  14  and  15 .  
         [0028]     In the embodiment of  FIG. 1 , two cores are required for molding the housing  5 , the first core being indicated by mold discharge direction  13  and the second core being indicated by mold discharge direction  15 . The mold discharge direction  14  of the molding tool is away from the cap  3 . The embodiment according to  FIG. 2  requires but one core for molding the air trap housing  5 . It is moved out of the lower section of the bore  8  in the direction of arrow  13 .  
         [0029]     By looking at both  FIGS. 1 and 2  it will become apparent that the housing  5  with its opening nipple  6  constitutes a part of the surface  7  of the outer wall of the washing fluid container cap  3 , the opening nipple  6  being preferably molded to extend in an upward direction and at an acute angle relative to the surface  7  of the outer wall. This area is formed by the single core, the arrow  15  representing it having been indicated to point in an upward direction. The other core serves to form the housing  5  with its downwardly opening section  8  which constitutes part of the inner wall surface  9  of the washing fluid container cap  3 . Preferably, the area  8  surrounding the lower opening of the air trap  4  extends downwardly at an acute angle relative to the inner wall  9 .  
         [0030]     As will be understood, the housing  5  of the air trap is formed or molded in the area of the wall of the washing fluid container cap  3  when the cores (not shown) are in their inserted state.  FIGS. 1 and 2  also show the partial section of the inner wall surface  9  within which the housing  5  is formed to be offset in a step-like manner so as to enlarge the section  8  of the opening. Step  10  is inclined to provide for a clean discharge from the mold. The walls  7  and  9  which form the housing  5  are disposed parallel to each other.  
         [0031]     In accordance with the embodiment of  FIG. 2  showing the opening nipple  6  for the hose to extend into the housing  5 , the opening nipple  6  may be molded by means of a single core within the molding tool. During manufacture the core is withdrawn in the discharge direction  13  from the inner chamber of the housing  5 .  
         [0032]      FIG. 3  is a detailed view of the opening nipple  6  showing a sealing shoulder  12  formed in the sleeve section  11  of the inwardly directed opening nipple  6 . The shoulder  12  effectively secures or seals any hose (not shown) inserted into the nipple  6 .  
         [0033]     The principles of manufacturing an air trap  4  in accordance with  FIGS. 1 and 2  are such as not to require any additional components. Also, when modifying the pressure indicating air trap, there is no need for changing the molding tool for the washing fluid container. A changed tool for molding the cap and, possibly, a differently shaped core for forming the housing  5  are all that may be required.  
         [0034]      FIGS. 4 and 5  depict separate presentations of an air trap  4 . The air trap is  4  arranged on a plastic washing fluid container, not shown in detail, of a washing machine. The container includes a cylindrical receptacle surrounding a drum. The air trap  4  is provided at the front surface of one of the caps  3  of the washing fluid container.  FIG. 4  only depicts a partial section of the wall  103  of the washing fluid container cap  3 . The air trap  4  is used to measure the level of washing fluid within the washing machine  30 .  
         [0035]     The housing of the air trap  4  consists of a lower housing section  104  which is open in a downward direction and an upper housing section  107  with an attached opening nipple  105  for a hose (not shown). The lower housing section  104  is integrally formed in, and penetrates through, the cap  3  of the washing fluid container.  
         [0036]     As may be seen in  FIG. 4 , the upper housing section  107  with its opening nipple  105  is pivotally connected to the lower housing section  104  by means of a foil hinge  108 . In this manner the washing fluid container cap  3  and the two housing sections  14  and  107  can be fabricated as a unitary component.  
         [0037]     It will be understood, that in correspondence with the two mold discharge directions shown, that integration of the air trap  4  into the wall  103  of the washing fluid container cap  3  may be carried out by two cores. For discharging, at least one core is moved in an upward direction as shown by arrow  121 , and a further core may be moved downwardly as shown by arrow  120 . The mold is discharged in a substantially horizontal direction away from the outer surface of the wall  103 , as indicated by arrow  119 .  
         [0038]     As shown in  FIG. 4 , the lower housing section  104  occupies a partial section of the surface  109  of the outer wall of the washing fluid container cap  3  and protrudes in the manner of a wedge from the wall  103  in an upward direction at a preferably acute angle with respect to the surface  109  of th outer wall, resulting in an opening  110  of rectangular or square cross-section with respect to the outer surface.  
         [0039]     Moreover,  FIG. 4  shows that the downwardly directed section  111  of the lower housing section  104  occupies a partial section of the surface  112  of the inner wall of the washing fluid container cap  3 . The opening section  111  is preferably formed to extend downwardly at an acute angle relative to the surface  112  of the inner wall. The downwardly open section  111  of the lower housing section  106  is offset in a step-like manner in order to enlarge the section  110  of the opening. The step  113  extends at an incline.  
         [0040]     As may be seen in  FIGS. 4 and 5 , the lateral walls  106 . 1  and  106 . 2  forming the lower housing section  104  are disposed parallel of each other resulting in a rectangular profile over the extent of the housing interior. As shown in  FIG. 4  in the opened state of the upper housing section  107 , the upper housing section  107  is provided with a circumferential groove  114  for receiving a gasket (not shown). It can also be seen that lugs  115 . 1  and  115 . 2  are provided at the outer wall of the upper housing section  107  to provide a snap-like or latched closure. To carry out the latched closure, the lateral side walls  106 . 1  and  106 . 2  of the lower housing section  104  are provided with ribs  116 . 1  and  116 . 2  extending beyond the opening range  110 . Within the ribs  116 . 1  and  116 . 2  there are provided bores  117 . 1  and  117 . 2  into which the lugs  115 . 1  and  115 . 2  penetrate in the closed state of the housing. The ribs  116 . 1  and  116 . 2  constitute a partial extension of the lateral walls  106 . 1  and  106 . 2 . Furthermore,  FIG. 4  shows the outwardly directed edges of the ribs  116 . 1  and  116 . 2  to be inclined. Over their extent the two inclines are beveled inwardly. The beveling serves during pivoting of the upper housing section  107  when the lugs  115 . 1  and  115 . 2  contact the inner edge of the ribs  116 . 1  and  116 . 2  slightly to spread the ribs  116 . 1  and  116 . 2  outwardly which causes the lugs  115 . 1  and  115 . 2  to rub along the inner surface of the ribs  116 . 1  and  116 . 2 . As soon as the lugs  115 . 1  and  115 . 2  have arrived at the bores  117 . 1  and  117 . 2  they will snap into the bores, so that, as shown in  FIG. 5 , the upper housing section  107  becomes firmly connected with the lower housing section  104 . It will be understood that the snap-fit takes place only after the seal engages the frame  110  of the opening.

Technology Classification (CPC): 3