Patent Publication Number: US-2020277723-A1

Title: Washing device comprising a washing drum with profile elements

Description:
The present invention relates to washing devices, more particularly to human-powered washing devices, comprising a washing drum provided with profile elements on the interior surface thereof. 
     Human-powered washing device are frequently used when delicate goods, e.g. delicate fabrics, have to be washed, when only a small amount of goods, e.g. laundry, has to be washed or when electricity is not available, such as during (backcountry) camping. Use of a human-powered washing device may also be part of a more ecological or self-supporting lifestyle. Such human-powered washing devices comprise a washing drum, rotatable around an axis of rotation using human power, e.g. manually operated using one or more handles or operated by foot using pedals. 
     Similar to mains-powered washing devices, one of the requirements that washing drums of hand-operated washing devices have to fulfil is that they have to be stiff under rotation. That is, they should resist deformation when rotating while water, or any other liquid, detergent and goods are provided to and tumble in the washing drum. Moreover, in both mains-powered washing devices and human-powered washing devices the quality of the cleaning provided by the washing device is dependent on the mixing of liquid and detergent, and the mixing of liquid and detergent with stains or dirt in the goods. The mixing ensures that the detergent is present throughout the liquid and can thus reach all stains or dirt in the goods. 
     Compared to mains-powered washing devices, hand-operated washing drums however bring along their own set of requirements. For instance, in human-powered devices the weight of the washing drum is of importance. The washing drum has to be light, so that the total weight that has to be brought in motion by the user remains limited and therefore the washing device can be operated solely using human power. 
     Current human-powered washing devices are for example the Drumi (Yirego| Makers of the Drumi, website, Yirego, retrieved on 18 Dec. 2015, retrieved from the Internet, &lt;URL: http://www.yirego.com/&gt;), the Laundry Pod (Laundry Pod Eco Friendly Hand Washing Machine, short movie, Store Bound, retrieved on 18 Dec. 2015, retrieved from the Internet: &lt;URL: https://www.youtube.com/watch?v=MohLBaYJpDc&gt;) and the Wonder Wash (Wonder Washer-Washing clothes, short movie, biblesnbarbells, retrieved on 18 Dec. 2015, retrieved from the Internet, &lt;URL: https://www.youtube.com/watch?v=JPcod_sqbos&gt;). These human-powered washing devices are provided with a washing drum comprising a smooth interior surface, in some cases a smooth interior surface interrupted only by holes and/or paddle elements. 
     It is the object of the present invention to provide a washing device comprising a washing drum that facilitates the mixing of water and detergent. 
     The washing device, e.g. a human-powered washing device, is suitable for the washing of goods, e.g. laundry. It comprises a washing drum rotatable about an axis of rotation. Said axis of rotation extends in an axial direction. 
     Said washing drum comprises a drum wall with an interior surface and an exterior surface. The interior surface extends along the axial direction and encloses in a rotational direction about said axis of rotation of the washing device. 
     Said washing device moreover comprises a plurality of profile elements provided to the interior surface of said drum wall, wherein each profile element comprises a plurality of ribs. Each rib extends along the interior surface of the drum wall between two ends by a rib length and extends from the interior surface into said interior of the washing drum by a rib height. In the axial direction, i.e. the axial direction of the axis of rotation, of the interior surface of the drum wall, i.e. along the interior surface of the drum wall, the rib height varies along the rib length. The ribs are connected to each other at their ends so as to form a profile element embodied as a closed contour around a cavity that is open opposite from the drum wall, e.g. three ribs forming a triangular contour, e.g. two curved ribs forming a circular or oval contour profile element. Profile elements adjacent in the rotational direction of the washing drum are offset in respect of each other in the axial direction. 
     The present inventor has determined that a smooth interior surface of a washing drum is disadvantageous to the mixing of water and detergent. While this disadvantage was realized in the context of human-powered washing devices, said smooth interior surface may be disadvantageous to the mixing of water and detergent in mains-powered washing devices as well. 
     In prior art human-powered washing devices water flow is namely fully or predominantly along the rotational direction, as the water is dragged along by the direction of motion of the washing drum, which is in the rotational direction. In the inventive washing device the variation in rib height in the axial direction creates a variation in the flow resistance encountered by the water flow in the axial direction, wherein said resistance is lower when the rib height is lower. As the profile elements form a closed contour, the variation in height along the rib length provides for a variation in height in the axial direction. The variation in resistance along the axial direction thus generates a flow in the axial direction directed to those regions where the resistance is minimal, that is, to regions of the profile element where the rib height is minimal or to regions between neighbouring disjunct profile elements. 
     Said flow in the axial direction may be a turbulent flow, dependent upon amongst others the velocity of the flow and the shape of the profile element. A turbulent flow is advantageous, as it tends to increase the mixing of water and detergent. Moreover, said turbulent flow may also lead to a larger volume or a more turbulent flow of water with detergent that flows through the goods in the washing drum. This may in turn lead to more rapid or more complete removal of stains or dirt from said goods. 
     The flow in the axial direction generated by a profile element, more particularly generated by the variation in the axial direction in height along their length of the ribs that make up the profile element, preferably mixes with another flow in the axial direction generated by other nearby profile elements or with a flow along the rotational direction of the drum. 
     As a result of the offset in respect of each other of profile elements adjacent in the rotational direction of the washing drum, said offset in the axial direction, the flow in the axial direction generated by a profile element, more particularly generated by the variation in the axial direction in height along their length of the ribs that make up the profile element, may encounter another profile element, said profile element as described above, that will direct the flow into a, possibly opposite, axial direction. The profile element may also separate the flow into several flows propagating in different directions. Moreover, said flow preferably mixes with another flow in the axial direction generated by other nearby profile elements or with a flow along the rotational direction of the drum. Said flow may mix again with other flows generated by other profile elements. Altogether said profile elements generate a plurality of meandering or zig-zag flows, that is, flows with components in the axial direction, along the interior surface of the washing drum. Accordingly, the profile elements adjacent in the rotational direction of the washing drum may be offset in respect of each other in the axial direction in an (overlapping) zig-zag pattern, the offset in the axial direction being less than a width of the profile elements in the axial direction. The zig-zag pattern provides a repetitive zig zag offset (i.e. following profile elements along the rotational direction are alternately offset opposite in the axial direction) Hence, neighbouring profile elements in the rotational direction partly overlap as the offset is less than a width of the profile elements. Thus, each profile element generates during rotation an axial component of the water flow due to the variation of the rib height in axial direction, and as neighbouring profile elements seen along the direction of rotation, are offset in respect of each other in the axial direction, the axial components of the water flow of neighbouring profile elements along the direction of rotation are offset in respect of each other causing the neighbouring profile elements to generate different, preferably opposing axial flow components, which increase turbulence of the water. Said flows in the axial direction may be irregular spaced, if the plurality of profile element are differently shaped or provided at various distances from each other, or may be regular, when identical profile elements are provided at a fixed distance from each other. The repeated mixing and separation of flows by the variation in profile element height along the axial direction may thus lead to increased mixing of the water and detergent, and may also lead to increase flow of water and detergent through the goods, thereby improving the removing of stains or dirt. 
     The offset in the axial direction of profile elements adjacent in the rotational direction makes that at least some flows in the axial direction will encounter a profile element along their path, thereby generating an flow component in the axial direction to the flow that was up to then fully in the rotational direction. Thus, the offset increases the percentage of flow in the rotational direction along the interior surface of the drum wall that encounters a profile element, said profile element having a height that varies in the axial direction. 
     The above describes possible effects of the profile elements, said profile comprising a plurality of ribs having a variation in height along their length in the axial direction, spatially along the interior surface of the washing drum. Considering a certain volume of water and detergent in the interior of the washing drum near the interior surface thereof in time, said volume of water will experience a time-varying resistance, as the resistance will be higher when a profile element with rib section of relatively large height passes, while the passing of a rib with low rib height, or an interior surface are without a rib, will result in a lower resistance. When a profile element passes, the variation in rib height in the axial direction creates a gradient in the flow resistance in the axial direction, and therefore a flow in the axial direction. When at a later time another profile element with a rib height variation in the axial direction opposite to that of the previous profile element passes, a flow in the axial direction in the opposite direction will arise. Moreover, the rotation of the drum creates a flow in the rotational direction along with the flows in the axial direction. Altogether a time-varying flow pattern, possibly a time-varying turbulent flow pattern, will arise, which may be a repeating or an irregular pattern. Said pattern may lead to increased mixing of water and detergent, and more flow of water and detergent through the goods provided in the washing drum, thereby improving the quality of the cleaning provided by the washing device, liquid and detergent. 
     Moreover, said profile elements embodied as closed contours may contribute to the stiffness of the washing drum, and may therefore contribute to the stability of the washing device. Comprising elements connected to each other end-to-end to form a closed contour, the profile elements have an internal firmness or stiffness, that, when provided to the interior surface of the drum wall, will contribute to the stiffness of the washing drum. 
     In an embodiment, the ribs form protrusions that extend in a radial direction inwardly from the interior surface of the washing drum. The ribs protrude, preferably by the rib height, in respect of the interior surface of the washing drum, the interior surface at enclosed by, i.e. in, the closed contour. Also, the ribs protrude, preferably by the rib height, in respect of the interior surface of the washing drum, the interior surface at an outside of, i.e. out of, the closed contour. Hence, the ribs provide a resistance to the water in either direction of rotation, causing the turbulence effects to occur in either direction of rotation. The interior surface of the washing drum enclosed by the closed contour may be flush with the interior surface of the washing drum outside the closed contour, to promote a homogeneous thickness and strength of the drum wall and to promote a similar flow resistance and turbulence in either direction of rotation of the drum. In this case, when the drum is cylindrical, a distance of the interior surface of the drum to the axis of rotation is constant. 
     In an embodiment, the ribs have an inside side wall surface protruding from the interior surface of the washing drum enclosed by the closed contour and an outside side wall surface protruding from the interior surface of the washing drum outside the closed contour, the inside and outside side wall surfaces protruding radially inward from the interior surface of the washing drum. Thus, the inside and outside side wall surfaces protrude perpendicular to a tangent plane of the interior surface of the washing drum at the rib. As the ribs protrude perpendicular to the inside surface of the washing drum, thus the ribs having side wall surfaces that extend radially in the direction of the axis of rotation, a relatively high flow resistance is provided by the side wall surfaces, while at the same time an amount of material to be used, e.g. when injection moulding the washing drum, may be kept relatively low, enabling to provide washing drum at a relatively high strength, a relatively low weight, providing a relatively high turbulence when rotating and which can be manufactured using a relatively low amount of material. 
     In an embodiment, an exterior surface of the drum wall is substantially flush along a direction of rotation, promoting a low flow resistance at an outside of the washing drum, hence promoting rotation of the drum at a low drive force. 
     The washing drum may have various shapes, such as cylindrical, ovoidal, or spherical, or may comprise a cylindrical, ovoidal or spherical portion. The drum wall is embodied accordingly. 
     The interior surface of the drum wall encloses in a rotational direction about said axis of rotation of the washing device, that is, it forms a closed contour about said axis of rotation of the washing device. This contour may be circular, in which case the interior surface of the drum wall encircles in a rotational direction about said axis of rotation. Although the circular contour about said axis of rotation of the washing device is preferred, as the force exerted to rotate the washing drum in such a circular embodiment is constant during a revolution, the closed contour may be differently shaped, e.g. oval or octagonal. 
     In a preferred embodiment the washing drum comprises a cylindrical main part. In this preferred embodiment the interior surface of the drum wall encircles in a rotational direction about said axis of rotation of the washing device equidistant from said axis of rotation, and said interior surface extends along the axial direction. In this embodiment the rotational direction comprises a curvature, as it encircles about the axis of rotation. The axial direction is straight, as the cylinder surface is equidistant from the axis of rotation. The axial direction is here thus fully parallel to, that is, fully along, the axial direction. 
     A washing drum comprising such a cylindrical portion is preferred, as such a portion allows for the provision of slidable drum wall parts that are in a simple manner slidable parallel to the axis of rotation in between and from between fixed drum wall parts. The slidable drum wall parts allow to provide an aperture to the drum wall, said aperture allowing goods to be inserted into said washing drum, and allow to cover said aperture, thereby closing said washing drum. These slidable drum wall parts are advantageous, as the washing drum can be rotated, and washing can be performed, with and without the slidable drum wall part being present on the washing drum. Taking the slidable drum wall part out during washing can be preferred when the goods should be observed during washing, or when goods are removed from and inserted into the washing drum frequently. 
     In an embodiment having a spherical or ovoidal drum wall the interior surface encloses in rotational direction about said axis of rotation of the washing device and extends along the axial direction. However, as in this embodiment both the rotational direction and the axial direction comprise a curvature, the interior surface extends in a direction perpendicular to said rotational direction also towards or from the axis of rotation. That is, said interior surface extends perpendicular to said rotational direction in a direction that has a component parallel to the axial direction and a component towards or from said axis of rotation. 
     Preferably the profile elements adjacent in the rotational direction of the washing drum are provided partially in front of each other in the axial direction. In this way liquid flowing in the rotational direction of the drum will encounter a profile element along a full rotation, said profile element generating a flow in the axial direction. An unobstructed path in the rotational direction is thus prevented by said placement of profile elements, and thus more flows in the axial direction are created. 
     Preferably a plurality of holes extend through said drum wall from the interior surface to the exterior surface thereof, wherein each hole ends on the interior surface within a closed contour of a respective one of the profile elements. The provision of a hole that ends within a profile element provides water to the interior of a profile element. Said water will flow out of said profile element along a direction influenced by the height of the ribs that form the profile element. As the variation in height of the profile element is provided along a section of the profile element length that extends at least partially in the axial direction, a flow in the axial direction will be created if the location of the hole through the drum wall is aligned in rotational direction by a section of large height of the profile element. For example, seen in radial direction, the holes may be provided centrally in each closed contour formed by the profile elements. As another example, a hole may be provided in the center of a profile element embodied as a circular contour, wherein the height of said contour reaches a maximum at the section of said circle that extends furthest along the rotational direction. In this situation a flow of water out of said contour will be at least partially in the axial direction. 
     Moreover, the presence of holes extending through the drum wall is preferred, irrespective of their position with respect to the profile elements, as the flow of water through the holes while the drum rotates is likely a turbulent flow, thereby leading to mixing of water and detergent. 
     The holes may have a various cross-sectional shapes, such as hexagonal, circular or rectangular. 
     A profile element embodied as a closed contour comprises a plurality of ribs that preferably have a rib width perpendicular to the rib length and perpendicular to the rib height, whereby the rib width is constant over the rib height. In this case the ribs may extend into the interior of the washing drum perpendicular to the interior surface of the washing drum, that is, at a right angle to said interior surface, or they may extend into the exterior of the washing drum at an angle different from a right angle. A perpendicular orientation of the profile element is preferred, as it creates a larger resistance for the water flow independent of the direction of rotation, that is, independent of whether the rotation of the drum is clockwise or counter clockwise, and may therefore contribute to obtaining a turbulent, mixing, flow. Moreover, said perpendicular orientation of the ribs may be the orientation that is easiest to obtain in an injection moulding process, and also for this reason the ribs extending into the interior of the washing drum perpendicular to the interior surface of the washing drum is preferred. 
     The ribs may be curved ribs or straight ribs, that is, ribs curved or straight along their length. If two curved ribs are connected at their ends the individual ribs may not be discernible in the profile element, as the rib ends may have the same orientation. This is for instance the case when two curved ribs form an oval closed contour. The ends of the two curved ribs have the same orientation, that is, the lines tangent to the ends of two curved ribs that form an oval closed contour overlap. Tangent lines do not overlap when straight ribs are provided at an angle to each other. In such an embodiment that comprises straight ribs provided at an angle to each other the individual ribs are generally discernible. 
     Preferably the closed contour is a polygonal closed contour comprising a plurality of straight ribs, that is, ribs straight and thus without curvature along their length, connected end-to-end, wherein neighbouring profile elements adjoin along the length of said ribs, so as to provide to said interior surface of the drum wall a grid. 
     The plurality of profile elements may thus be disjunct or adjoined. When said profile elements are disjunct, some liquid will directed by the profile element to portions of said interior surface in between profile elements, as the profile elements extend into the interior of the washing drum from the interior surface and are thus elevated portions with respect to the interior surface that create a larger resistance than said surface. 
     When said profile elements are adjoined, e.g. adjoined over the length of their ribs, liquid flows over the profile elements. The height variation of the ribs along their length in the axial direction, together with the offset in the axial direction of profile element successive in the rotational direction will generate a flow component in the axial direction over the grid formed by the adjoining profile elements. 
     Profile element may be adjoined only at a vertex, may be adjoined along part of the length of their ribs or may be adjoined along the full length of their ribs. 
     The adjoining of ribs is preferred, as it further contributes to the stiffness of the washing drum. 
     The plurality of profile elements can comprise a plurality of different profile element, e.g. comprising various polygonal contours, but can also be a plurality of identical profile elements. 
     Neighbouring identical profile elements, said profile elements being polygonal closed contours comprising a plurality of straight ribs, that is, ribs that are along their length straight and thus without curvature, connected end-to-end, can adjoin along the length of said ribs, so as to provide to said interior surface of the drum wall a regular grid. 
     Preferably the closed contour comprises an even number of straight ribs connected end-to-end under an angle so as to provide a number of vertices equal to the number of ribs, wherein the height of the ribs varies between a maximum height at one end and a minimum height at the other end so as to provide to said profile element alternating vertices of maximum height and vertices of minimum height. 
     In this embodiment the maximum height and minimum height of the profile element is attained at the vertices of the profile element. The height of the rib along its length in the axial direction may vary in different ways. For instance, the height may vary linearly with length, may be constant along a section of the length of the rib, or may vary more strongly near one rib end than near the other one. 
     Preferably the height of the vertices of maximum height is smaller than 4 cm, e.g. 3 cm, and the height of the vertices of minimum height is larger than 4 cm, e.g. 5 cm, for an estimated volume of the washing drum of approximately 20 litres. This height leads to flows in the axial direction that facilitate mixing, while limiting the power needed to rotate said drum with fluid and goods to a level at which the use of the washing device is still pleasant. 
     Preferably the volume of the washing drum is between 10 L and 50 L, as such a volume is large enough for washing either large goods, such as bedclothes, or simultaneous washing of a few pieces of smaller goods, e.g. a few articles of clothing, while limiting the power needed to rotate said drum with fluid and goods to a level at which the use of the washing device is still pleasant. 
     The profile element embodied as a closed contour may attain various shapes, such as circular, oval, triangular, rhombic, squared, pentagonal, hexagonal or star-shaped. 
     Of the abovementioned closed contour profile elements, a hexagonal contour profile element can be adjoined along its ribs by other identical hexagonal contour profile elements, so as to provide a grid. Moreover, in said grid the hexagonal contour can be oriented such that in the rotational direction the front end and rear end of said hexagonal contour are a vertex. The height of each rib varies along its length between a maximum height at one end and a minimum height at the other end, thereby providing the profile element with alternating vertices of maximum height and vertices of minimum height. Neighbouring profile elements adjoin to form a grid, the ribs extending from the front end vertex of one profile element each extend to a rear end vertex of a respective offset neighbouring profile element. Then, if the vertices have alternating maximum and minimum height, said front end and rear end are a maximum height vertex and a minimum vertex, while two other vertices of minimum height of said hexagonal contour are offset in axial direction and form a front end vertex of an offset following profile element along the direction of rotation. As a result of said height variations and orientation with respect to the rotational direction, said profile element will generate a flow in the axial direction in each profile element and slightly above said profile element inwards into the interior of the drum. Due to the zig zag type offset, the flows in axial direction will alternate in direction per profile element hence providing a mixing. Thus, the hexagonal contour profile element is preferred as it combines the generation of a flow in the axial direction with the ability to form a grid. As a result, a grid is provided that may result in a high turbulence while it may provide a high strength at a low weight due to the “honeycomb” shaped interconnected grid. Furthermore, the alternating low end and high end vertices promote an easy release of the drum from an injection mould in the case of injection moulding. 
     Preferably the hexagonal contour comprises six vertices with an angle between ribs of 120 degrees, said angles those in the interior of the hexagonal contour profile element. 
     Preferably the exterior surface of the drum wall is embodied as a smooth exterior surface only interrupted by the holes extending through said drum wall. 
     This smooth exterior surface of the drum wall of an embodiment of the inventive washing drum is thus different from the metal drum wall provided in mains-powered washing machines, wherein embossings are provided. Said embossings are deformations of the drum wall, wherein e.g. a protrusion into the interior of the washing drum is accompanied by an indentation on the exterior of said drum wall. 
     Preferably the drum wall is a cylindrical drum wall and comprises a plurality of fixed drum wall parts and one or more slidable drum wall parts, wherein the slidable drum wall parts are slidable parallel to the axis of rotation of the washing drum out from between and in between two fixed drum wall parts, so as to provide an aperture to the drum wall, said aperture allowing goods to be inserted into said washing drum, and so as to cover said aperture, thereby closing said washing drum. 
     The washing drum can be rotated, and washing can be performed, with and without the slidable drum wall part being present on the washing drum. Taking the slidable drum wall part out during washing can be preferred when the goods should be observed during washing, or when goods are removed from and inserted into the washing drum frequently. 
     Preferably said drum wall and plurality of profile elements are embodied as a plastic drum wall and a plurality of plastic profile elements, wherein the profile elements are formed integrally with said drum wall. Such a plastic drum wall with plastic profile elements formed integrally with said drum wall is preferred, as it provides a lightweight yet sturdy washing drum. The profile elements provided to the interior surface of the washing drum may, as described in the foregoing, contribute to providing those lightweight and sturdy properties to the washing drum. Moreover, said plastic drum wall can be mass-fabricated using well-known moulding techniques, such as injection moulding. 
     Preferably the axis of rotation of said washing drum is a horizontal axis of rotation, as with said axis of rotation the profile element will during a full rotation of the washing drum be rotated from a position below water level to a position above water level. During said rotation the profile element draws some liquid, e.g. liquid with detergent, of the liquid provided inside the washing drum, as the ribs that form the profile element extend from the interior surface of the drum wall into the interior of the drum. The profile element, as it extends into the interior of the washing drum, thus provides a small ‘pocket’ or cavity in which some water can be kept along a part of the rotation of the washing drum. The water only falls from the washing drum at a later time during the rotation of the drum at a distance above the liquid level in the washing drum. Said falling of water from a above the liquid level into the liquid may also generate increased turbulence and mixing of water and detergent, and as the water and detergent are in contact with air, may lead to increased foam formation. 
     In some situations, for instance dependent on the rotational speed of the drum, the water may not fall down from the washing drum, but may flow along the interior surface the drum downward. Thus, a flow in the axial direction through the presence of the ribs with a variation in height along their length in the axial direction as described above may not only occur under water, but may be seen above the water level. This flow along the interior surface of the drum may in particular occur when the water level in the drum is below the axis of rotation of the drum, that is, when the washing drum is less than half filled with fluid. 
     Moreover, when in a washing drum provided with a horizontal axis of rotation the rib width is constant along the rib height a right angle between the interior surface and the rib is provided. Said right angle increases the ability of the profile element to draw liquid from the liquid provided inside the drum wall and to carry along said liquid along a part of the rotation of said drum wall is increased. 
     Moreover, a horizontal axis of rotation is preferred as also the goods provided to the washing drum may be carried upwards along a portion of the interior surface of said washing drum before falling down, and said falling may increase mixing of water and detergent, and may increase the flow of water with detergent over and through the goods, which also contributes to the cleaning of the goods. 
     The washing device may further comprise an enclosure surrounding substantially the lower half of the washing drum, two spindles attached to opposing ends of the washing drum along the horizontal axis of rotation thereof, and two bearing blocks. The two bearing blocks are each provided with a bearing. Moreover, the bearing blocks are insertable into and removable from opposed ends of said enclosure from the top thereof, wherein said opposed ends are provided along said horizontal axis of rotation of the washing drum. Said bearing blocks allow the assembly of washing drum, spindles and bearing blocks to be inserted into and removed from said enclosure, e.g. for transporting laundry after washing to a drying location. 
     Preferably said enclosure comprises a reservoir for liquid, e.g. water with detergent, in an upper part thereof. Said reservoir is provided with a liquid inlet that allows filling of said reservoir using a hose connected to said liquid inlet. Moreover, said reservoir comprises an outlet in a low-lying portion of said reservoir, wherein a hose is connectable to said outlet. In a preferred embodiment the liquid outlet serves also as a liquid inlet, and thus only a single opening in a low-lying portion of the reservoir and only a single hose connector are provided to the device. 
     Preferably, said washing device is embodied as a hand-operated washing device comprising a handle to rotate said washing drum about its axis of rotation. Compared to a foot-operated device, said hand-operated device may provide a more direct operation of, and therefore more control over, the washing device. Moreover, the hand-operated washing device may allow one to keep a closer eye on the goods during washing, for instance when the slidable drum wall parts are removed from the drum wall, than is possible using a foot-operated device. The handle may comprise a lock pen that fixes the position of the handle with respect to the enclosure to prevent unwanted rotation of said washing drum. 
     Optionally the washing device may be embodied as a human-powered washing device as described in the foregoing that can also be powered by another power source, such as mains power or a battery. A suitable electric motor is in this embodiment provided to the washing device. In this embodiment the washing device is thus a human-powerable washing device. The electric motor may be attached to the washing device when washing should be done with the power source different from human power, and may be removed again when human-powered washing is performed. Alternatively, the electric motor may be present on the device at all times and have a coupled position and an uncoupled position, in which coupled position the electric motor can power the washing drum and in which uncoupled position the electric motor does not provide an extra resistance to the rotation, e.g. does not provide an extra resistance when a user exerts a movement that is transferred to a of the washing drum about its axis of rotation. 
     The present invention also relates to a method to wash goods, e.g. laundry, wherein use is made of a washing device according to the present disclosure, said method comprising the steps of:
         inserting goods, e.g. laundry, into said washing drum,   providing liquid, e.g. water, and detergent to the enclosure, and   exerting a movement that is transferred to a rotation of said washing drum about its axis of rotation, wherein the profile elements provided on the interior of the drum wall provide to the liquid near said profile elements a flow component in the axial direction, wherein said flow component facilitates the mixing of liquid and detergent.       

     Moreover, when said washing device is provided with an enclosure, spindles and two bearing blocks according to the present disclosure, the present invention relates to a method to wash and transport goods according to the present disclosure, said method further comprising the steps of:
         removing water mixed with detergent from said enclosure, and   removing for transport the assembly of washing drum with goods, spindles and bearing blocks from said enclosure.       

    
    
     
       The invention will now be discussed with reference to the drawings. In the drawings: 
         FIG. 1  shows a side view of a washing device according to the invention. 
         FIG. 2  shows a side view of the washing drum of the washing device of  FIG. 1 . 
         FIG. 3  shows a side view of the interior surface of a fixed drum wall part of the washing drum of  FIG. 2 . 
         FIG. 4  shows another side view of the interior surface of a fixed drum wall part of the washing drum of  FIG. 2 . 
         FIG. 5  shows a side view of the exterior surface of a fixed drum wall part of the washing drum of  FIG. 2 . 
         FIG. 6A  shows a schematic top view of the profile elements provided on the interior surface of the drum wall part of  FIG. 4 . 
         FIG. 6B  shows a schematic cross-section through the profile elements of  FIG. 6A  along ribs thereof showing the variation in height of the ribs along their length in the axial direction. 
         FIG. 6C  shows a schematic cross-section through the profile elements of  FIG. 6A  along ribs thereof showing the variation in height of the ribs along their length in the axial direction. 
         FIG. 6D  shows a schematic cross-section through the profile elements of  FIG. 6A , said cross-section showing the width of a rib along its height. 
         FIG. 7  shows the enclosure of the washing device of  FIG. 1 . 
         FIG. 8A  shows a side view of a bearing and bearing block of the washing device of  FIG. 1 . 
         FIG. 8B  shows a side view of a portion of the washing device of  FIG. 1  during assembly thereof. 
         FIGS. 9A and 9B  show respectively a top view and schematic cross-section of another embodiment of the profile elements of the washing device according to the invention. 
         FIGS. 10A and 10B  show respectively a top view and schematic cross-section of yet another embodiment of the profile elements of the washing device according to the invention. 
     
    
    
     With reference to the drawings embodiments and optional features of the washing device will be described. 
     The washing device  1  shown in  FIG. 1  comprises a washing drum  2 , a handle  3 , an enclosure  4 , and a suspension of said washing drum  3  in said enclosure  4  comprising two spindles  51  and two bearing blocks  43 . 
     The rotary motion of the washing drum  3  can generated by a user through movement of the handle  3 . The shown embodiment of the washing device  1  is thus a hand-powered washing device. A lock pen  31  is provided to said handle  3  to fix the position of the handle  3  with respect to the enclosure  4 . 
     The washing drum  2  is shown in more detail in  FIG. 2 . The washing drum  2  is rotatable about a horizontal axis of rotation  200  extending in an axial direction and comprises a drum wall  20  that comprises a cylindrical main part  201  and two side parts  202 . The cylindrical main part  201  is provided equidistant around said horizontal axis of rotation  200 . Said horizontal axis of rotation  200  is thus a central horizontal axis of rotation. The two side parts  202  both comprise a concave surface connecting the cylindrical main part  201  to a circular end surface  203  perpendicular to the axis of rotation  200 . Altogether the cylindrical main part and side parts form a container that can enclose the goods in its interior. 
     Both the cylindrical main part  201  and concave surfaces of the side parts  202  comprise a plurality of holes  24  that extend through the drum wall. 
     The cylindrical main part  201  comprises one or more slidable drum wall parts  21  and a plurality of fixed drum wall parts  22 , wherein the slidable drum wall parts  21  are slidable parallel to the axis of rotation of the washing drum out from between and in between two fixed drum wall parts  22 , so as to provide an aperture to the drum wall  20 , said aperture allowing goods to be inserted into said washing drum  2 , and so as to cover said aperture, thereby closing said washing drum  2 . 
     A spindle  51  is provided to each of the circular end surfaces  203  of the side parts  202  of the drum wall  20 . The axis of each spindle  51  extends along the horizontal axis of rotation  200  of the washing drum  2 . 
     It is seen in  FIG. 2 , and more clearly in  FIG. 3 , that triangular paddle elements  23  are provided to the interior surface of the washing drum  2 , more particularly to the interior surface  222  of one or more fixed drum wall parts  22  thereof. 
       FIG. 3  also shows the holes  24  that extend through the drum wall and the profile elements  25  that are provided to the interior surface  222  of the drum wall. Each profile element  25  is embodied as a hexagonal closed contour around a cavity  255  that is open opposite from the drum wall. Each of the plurality of holes  24  through the drum wall  20  ends on the interior surface within a closed contour of a respective one of the profile elements  25 , more particularly in the center of a respective one of the profile elements  25 . The profile elements are shown more clearly in  FIG. 4 . 
       FIG. 4  shows the interior surface  221  of said fixed drum wall part  22 ,  FIG. 5  the exterior surface  222  thereof. The slidable drum wall parts  21  comprise the same features as those described for the fixed drum wall part  22 , with the exception of the features related to the paddle elements  23 , which features are absent in the slidable drum wall part  21 . 
     As the drum wall parts  21 ,  22  are parts of the cylindrical main part  201  of the washing drum  2 , the interior surface of said drum wall parts extends in the axial direction AD and encircles in a rotational direction RD about said axis of rotation of the washing device. 
       FIG. 4  shows the profile element  25  embodied as a hexagonal contour provided to the interior surface  221  of the drum wall, more particularly to the interior surface  221  of a fixed part  22  of the drum wall  20 . Each profile element  25  comprises a plurality of ribs  26 . It is already apparent from  FIG. 4 , as will be described in more detail in relation to  FIGS. 6A-6D , that the height of said ribs varies along their length in the axial direction of the interior surface of said washing drum. 
     In  FIG. 5  it is seen that the exterior surface  221  of the fixed drum wall part is embodied as a smooth exterior surface only interrupted by the holes  24  extending through said drum wall part. 
     As the drum wall  20  comprises a cylindrical main part  201 , the drum wall parts  21 ,  22  have an overall curved shape. The exterior surface  221  of the drum wall parts  21 ,  22  is however, apart from the holes  24  extending through said drum wall, free of any local receding portions or local bulging portions, e.g. local receding portions or bulging portions related to the profile elements provided to the interior surface of the drum wall. 
       FIG. 5  shows pairs of nearby holes  231  with an enlarged diameter of an outer portion of said holes. Said holes  231  allow for the attachment of the paddle elements  23  to the drum wall. 
     The hexagonal contour profile elements  25  on the interior surface  222  of the washing drum  2  of  FIGS. 4 and 5  are shown in more detail in schematic drawings of  FIGS. 6A-6D . The axial direction AD of the interior surface  222 , here parallel to the axis of rotation  200  of the washing device, and rotational direction RD of the interior surface  222 , said rotational direction RD encircling about said axis of rotation  200  of the washing device  1 , are indicated in  FIG. 6A . 
     The hexagonal contour  25  comprises six identical ribs  26 , wherein each rib  26  extends along the interior surface  222  of the washing drum between two ends by a rib length  281 . Each rib  26  extends from the interior surface  222  into said interior of the washing drum by a rib height  29 . This is shown in  FIGS. 6B and 6C , where cross-sections through the drum wall  20  along the arrows indicated in  FIG. 6A  with ‘A’ and ‘B’ are shown, respectively, and wherein the direction inwards into the interior of the washing drum from the interior surface  222  of drum wall  20  is indicated with ‘I’. In the axial direction AD the rib height  29  varies along the rib length  281 . The six ribs  26  are connected to each other at their ends, so as to form a closed contour around a cavity  255  that is open opposite the drum wall  20 . The height of each rib varies along its length between a maximum height at one end and a minimum height at the other end. The profile element  25  thus comprises alternating vertices  261  of maximum height and vertices  261  of minimum height. The height of each rib varies linearly along its length between a maximum height and a minimum height. 
     The hexagonal contour profile element  25  is oriented such that in the rotational direction RD the front end and rear end of said hexagonal contour are a vertex  261 . In this orientation, as in any other possible orientation of said hexagonal contour, the rib height  29  thus varies along its length  281  in the axial direction AD of said interior surface  222  of the drum wall  20 . 
     Moreover, profile elements  25  adjacent in the rotational direction of the washing drum are offset in the axial direction AD and provided partially in front of each other in the rotational direction RD. 
     In the present embodiment the plurality of profile elements  25  are embodied as a plurality of identical hexagonal contour profile elements  25 . Neighbouring identical profile elements  25 , that is, identical adjacent profile elements  25  in the rotational and axial direction, adjoin along the length of said ribs  26  so as to provide to said interior surface of the drum wall a regular grid  27 . 
     A rib  26  has a rib width  251  perpendicular to the rib length  281  and perpendicular to the rib height  29 . In a cross-section of the drum wall  20  along the arrow indicated in  FIG. 6A  with ‘C’, shown in  FIG. 6D , it is seen that in the present embodiment the rib width  251  is constant over the rib height  29  and that the ribs extend perpendicularly to the interior surface of the drum wall into the interior of the washing drum. In  FIG. 6D  the direction inwards into the interior of the washing drum from the drum wall thereof is indicated with ‘I’. 
     As shown in  FIG. 1  the enclosure  4  is adapted to surround the lower half of the washing drum  2 . The surface of a top portion of the enclosure  4  generally follows the shape of the washing drum  2  as seen from a top view, that is, it comprises, seen from a top view, a main part and concave side parts that connect said main part to an end surface perpendicular to said axis of rotation. Said top portion narrows slightly from its top downwards. A support portion below said top portion narrows more strongly and then widens again near the bottom of the enclosure to provide a large support area, or foot, to the washing device. 
     In  FIG. 7  it is seen that the enclosure  4  comprises a reservoir  8  and an outer enclosure  9 . The reservoir  8  is provided within said top portion of the outer enclosure  9  and can contain a liquid, e.g. water with detergent. The reservoir  8  follows the shape of the drum, that is, it comprises a cylindrical main part and concave side surfaces connecting said cylindrical main part to an end surface perpendicular to the axis of rotation. A liquid inlet  41  and liquid outlet  42  are provided to the enclosure to respectively fill and empty the reservoir. The liquid inlet and liquid outlet can both be connected to a water hose with connector piece, so as to provide a simple way to fill said reservoir with liquid before washing and to remove said liquid again after washing. As the liquid inlet  41  and liquid outlet  42  are identical in appearance, alternatively only the liquid outlet  42  may be provided to the enclosure  4  and said liquid outlet  42  may also serve as a liquid inlet. 
     The outer enclosure may comprise two parts, a top portion that surrounds the reservoir  8  and narrows below said reservoir, and a support part, or foot part, that has a narrow upper end that is connectable to said top portion and widens again near the bottom to provide a large support area for the washing device. 
     In  FIG. 7  it is also seen that a recess  81  is provided to the end surfaces of the reservoir  8  to allow insertion of the bearing blocks  43 . Moreover, the reservoir comprises an indentation from the top thereof to allow for insertion of the spindle. The outer enclosure  9  comprises an indentation from the top surface as well, so that after insertion of the bearing block  43  into said recess  81  in the reservoir  8  the outer surface of the bearing block is flush with the outer surface of the outer enclosure  9 . 
     In  FIG. 8A  it is seen that the bearing block  43  comprises in its center a bearing  44 , e.g. a ball bearing. Moreover, it comprises two passages  46  through said bearing block at both sides of the bearing  44 . Into and along each passages  46  a spring and a ball at the end of said spring is provided (not shown), so as to form a ball plunger. The ball is provided at the end of said passage at the side of the bearing that is adjacent the reservoir  8  in the assembled state of the washing device. In the assembled state the ball in the passage is pushed by the spring partly into a circular notch  83  in the recess  81  in the reservoir  8 , so as to secure said bearing block in said recess  81 , while at the same time allowing the bearing block to be removed when a vertical lifting force is applied. The bearing block  43  is furthermore provided with indentations  45  on its sides. 
     In order to assemble the washing device  1 , a bearing  44  in a bearing block  43  is provided around each of the spindles  51  at the outermost ends of the washing drum  2 . As shown in  FIG. 8B , the assembly of washing drum  2 , spindle  51  and bearing block  44  including bearing  43  is then lowered into the enclosure  4  until the bearing block  44  is provided into the recess  81  of the reservoir, as shown in  FIG. 8 . The balls of the ball plungers are provided partly into the notches  83  in the recess  81  and the indentations  45  of the bearing blocks are provided into a protrusion  82  of the reservoir to hold the bearing block in place. 
       FIG. 9A  shows a schematic drawing of a top view of a plurality of identical profile elements  25  comprising four identical ribs  26  connected to each other at their ends to form a profile element embodied as a rhomb-shaped contour around a cavity  255  that is open opposite from the drum wall  20 . Each rib  26  extends between two ends along the interior surface  222  of said drum wall by a rib length  281  and extends from the interior surface into said interior of the washing drum by a rib height  29 . 
     Cross-sections along the axes A and B in  FIG. 9A , shown in  FIG. 9B , shows the varying rib height  29  along a section of the rib length  281  in the axial direction AD of the interior surface  222  of the washing drum  2 . The direction inwards into the interior of the washing drum from the drum wall thereof is indicated with ‘I’. Similar to the embodiment of  FIG. 6A-D  the rib height  29  is largest at one end of a rib  26  and smallest at the other end of said rib  26 , but unlike the embodiment of  FIG. 6A-D  the rib height  29  does not vary linearly with rib length  281 , but rather varies more strongly close to one rib end. Profile elements  25  adjacent in the rotational direction of the washing drum are offset in the axial direction AD and provided partially in front of each other in the axial direction AD. 
     In the present embodiment neighbouring profile elements  25  are provided at a distance from each other. 
     In the present embodiment the profile element  25  comprises four straight ribs  26  connected to each other at their ends under an angle so as to form four vertices  261 , wherein the height  29  of the rib  26  varies between a maximum height and a minimum height and wherein the contour is provided with alternating vertices  261  of maximum height and vertices of minimum height 
     The holes  24  are provided in between profile elements  25 . 
       FIG. 10A  shows a schematic drawing of a top view of a plurality of profile elements  25  embodied as oval contours around a cavity  255  that is open opposite from the drum wall. The oval contours are formed by two curved ribs  26 , that is ribs curved along their length  281 , connected end-to-end. In this embodiment the ends of the two ribs are not discernible, as those ends have overlapping tangent lines. Each rib  26  extends along the interior surface  222  of said drum wall  20  by a rib length  281  and extends from the interior surface  222  into said interior of the washing drum  2  by a rib height  29 . The non-linear variation in the height  29  of the rib along its length in the axial direction AD is shown in the cross-section of  FIG. 10B . The direction inwards into the interior of the washing drum from the drum wall thereof is indicated with ‘I’. The plurality of profile elements  25  of  FIG. 10A  are identical in shape, but their long axes  271  are oriented at various angles with respect to the rotational direction RD. For each profile element  25  the height of the ribs  26  vary along a section of their length  281  in the axial direction AD along said interior surface  222  of the washing drum  2 . Profile elements  25  adjacent in the rotational direction RD of the washing drum are offset in the axial direction AD. Some, but not all profile elements  25  adjacent in the rotational direction RD of the washing drum  2  are provided partially in front of each other in the axial direction AD. 
     Neighbouring profile elements in the embodiment of  FIGS. 10A-10B  do not adjoin.