Technical Field

The present invention relates generally to a sponge scrubber for cleaning bathtubs and the like.

Background

Solid rectangular sponge scrubbers are known for cleaning bathtubs and the like. Many of these sponge scrubbers are comparatively thick for ease of cleaning wide surfaces including the wall surface and the bottom surface of the bathtub. A sponge scrubber having a shape different from a solid rectangle has previously been proposed, for example, a sponge scrubber being configured in a triangular columnar shape having a prescribed thickness so that a front end easily bends (see Patent Document 1 , Japanese Utility Model Registration Publication No. 3023711).

Summary

A first aspect of the present invention is a sponge scrubber, being provided with a first part having a first surface and a first opposite surface facing opposite the first surface, and a second part having a second surface and a second opposite surface facing opposite the second surface. The second party is connected to the first part. A second thickness between the second surface and the second opposite surface is thinner than a first thickness between the first surface and the first opposite surface. The first opposite surface and the second opposite surface are a continuous flat surface. The first surface and the second surface are connected by an inclined surface.

In the present invention, the sponge scrubber has a first part and a second part thinner than the first part, and a first surface of the first part and a second surface of the second part are connected by an inclined surface. The sponge scrubber thereby has a rigid thick part and a softer thin part, and a wide flat surface is configured by a first opposing surface and a second opposing surface. Therefore, wide surfaces can be efficiently cleaned with the wide flat surface supportable by the thick part and narrow places can be easily cleaned by utilizing the thin part. The ability to fit corner parts of a bathtub, or the like, is improved by connecting the thick part and the thin part by the inclined surface such that and cleaning of the corner parts becomes easier. It is thus possible to clean all kinds of places including wide places, narrow places and corners.

Brief Description of the Drawings

FIG. 1 is a perspective view illustrating a configuration of a sponge scrubber according to a first embodiment of the present invention.

FIG. 2 is a drawing illustrating an example of using the sponge scrubber according to the first embodiment of the present invention.

FIG. 3 is a drawing illustrating an example of using the sponge scrubber according to the first embodiment of the present invention.

FIG. 4 is a drawing illustrating an example of using the sponge scrubber according to the embodiment example of the present invention.

FIG. 5 is a drawing illustrating an example of using the sponge scrubber according to the embodiment example of the present invention.

FIG. 6 is a drawing illustrating an example of using the sponge scrubber according to the embodiment example of the present invention.

FIG. 7A is a drawing illustrating a first comparative example of a sponge scrubber.

FIG. 7B is a drawing illustrating a second comparative example of a sponge scrubber.

FIG. 7C is a drawing illustrating a third comparative example of a sponge scrubber.

FIG. 8 A is an explanatory drawing of a curved surface of a sponge scrubber following testing.

FIG. 8B is an explanatory drawing of an undersurface of a sponge scrubber following testing.

FIG. 9 is a perspective view illustrating a configuration of the sponge scrubber according to a second embodiment of the present invention.

Detailed Description

The sponge scrubber 100 according to a first embodiment of the present invention is described below while referring to FIGS. 1 to 8. The sponge scrubber 100 according to the present embodiment is suited for cleaning bathtubs and bathrooms, but the use is not limited thereto, and the sponge scrubber can be used for cleaning all kinds of areas including sinks and wash basins. The constituent material of the sponge scrubber 100 is not limited, but a material having a standard hardness commonly used for cleaning, for example, a hardness of 100 N to 300 N, is possible. For example, polyurethane foam can be used.

FIG. 1 is a perspective view illustrating a configuration of the sponge scrubber 100 according to a first embodiment of the present invention. The sponge scrubber 100 is obtained, for example, by processing polyurethane foam into a prescribed shape by cutting, punching out, molding, or various other methods. In the following, for convenience, a front-rear direction (length direction), left-right direction (width direction), and up-down direction (thickness direction) are defined as illustrated, and the configuration of each part is described following these definitions.

As illustrated in FIG. 1, the sponge scrubber 100 is configured with a fixed width (W) across the front-rear direction, while the front portion is configured thinner than the rear portion. That is, the sponge scrubber 100 has a thick part 1 on the rear side and a thin part 2 on the front side connected by an inclined part 3. The thick part 1, as illustrated, has an upper surface 10 and a lower surface 11 parallel to each other, and the thickness HI between the upper surface 10 and the lower surface 11 may be fixed. The thin part 2 has an upper surface 20 and a lower surface 21 parallel to each other, and the thickness H2 between the upper surface 20 and the lower surface 21 may be fixed. The thickness HI of the thick part 1 is thicker than the thickness H2 of the thin part 2.

The lower surface 11 of the thick part 1 and the lower surface 21 of the thin part 2 configure a continuous flat surface. In the present specification, "flat" may be nearly flat on average, and a presence of fine unevenness or embossing on the surface can be ignored. Meanwhile, the upper surface 10 of the thick part 1 and the upper surface 20 of the thin part 2 are connected by an inclined surface 30 being an upper surface of the inclined part 3, and there is a difference of level between the upper surface 10 and the upper surface 20. The inclined surface 30 inclines at a prescribed angle of inclination Θ greater than 0° and less than 90° relative to an extended surface (horizontal surface) extending the upper surface 20 of the thin part 2 rearward. As illustrated, an upper end of the inclined surface 30 serving as a connecting part with the upper surface 10 of the thick part 1 and a lower end serving as a connecting part with the upper surface 20 of the thin part 2 each may be suitably surface finished to an arc form in section.

The sponge scrubber 100 furthermore has: left and right side surfaces 4 and 5 extending from left and right edges of the upper surfaces 10 and 20 and of the inclined surface 30 to left and right edges of the lower surfaces 11 and 21; a front surface 6 extending from a front edge of the upper surface 20 to a front edge of the lower surface 21; and a rear surface 7 extending from a rear edge of the upper surface 10 to a rear edge of the lower surface 11. The side surfaces 4 and 5, the front surface 6 and the rear surface 7, and the upper surfaces 10 and 20 and lower surfaces 11 and 21 intersect each other at right angles. As illustrated, the total length L of the sponge scrubber 10 is LI + L2 + L3, where LI is the total length of the thick part 1, L2 is the total length of the thin part 2, and L3 is the total length (length in the front-rear direction) of the inclined surface 3.

In the sponge scrubber 100 of the present first embodiment, the ratio of the thickness HI of the thick part 1 to the thickness H2 of the thin part 2 is about 1.3 or larger. The ratio may furthermore be about 1.5 or larger or about 2 or larger. The respective functions of the thick part 1 and the thin part 2 can be effectively expressed by providing such difference of thickness. Meanwhile, the ratio of the thickness HI of the thick part 1 to the thickness H2 of the thin part 2 is about 7 or smaller in order to further improve the ability to follow corner parts. The ratio may also be about 4 or smaller.

The thickness H2 of the thin part 2 is about 30 mm or smaller in order to be flexible and to facilitate cleaning narrow places. The thickness may furthermore be about 27 mm or smaller or about 25 mm or smaller. Meanwhile, the ratio is at least about 10 mm or larger or about 15 mm or larger in order to assure fixed durability.

Furthermore, the ratio of the length L2 of the thin part 2 to the total length L of the sponge scrubber is at least about 0.1 or larger in order to express the function of the thin part 2. The ratio may furthermore be about 0.2 or larger or about 0.3 or larger. Meanwhile, the ratio is about 0.8 or smaller or about 0.5 or smaller, because cleaning of a wide surface becomes difficult when the thin part 2 is too much longer than the thick part 1.

Furthermore, an angle Θ formed by the surface of the thin part 2 and the inclined surface 3 is about 11° or larger in order to assure a favorable ability to fit corner parts. The angle Θ also may be about 20° or larger or about 30° or larger. Meanwhile, the angle is about 70° or smaller or about 50° or smaller in order to assure a favorable ability to fit corner arts.

The sponge scrubber 100 of the present embodiment thus has a thick part 1 having a fixed thickness HI and a thin part 2 having a fixed thickness H2, and the thick part 1 and the thin part 2 are connected by the inclined part 3 (inclined surface 30). Therefore, the sponge scrubber 100 has a thick part 1 being comparatively high in rigidity and a thin part 2 being lower in rigidity and being more flexible, and can be used ideally for cleaning all kinds of places as follows, while assuring ease of handling during use.

An example of use of the sponge scrubber 100 according to the present embodiment, in particular an example of use in a bathroom, is described. In the following, the lower surface 11 of the thick part 1 and the lower surface 21 of the thin part 2 are collectively referred to as "first cleaning surface 101" of the sponge scrubber 100, and the upper surface 10 of the thick part 1, the upper surface 20 of the thin part 2, and the inclined surface 30 are collectively referred to as "second cleaning surface 102" of the sponge scrubber 100.

The case when cleaning a side surface or bottom surface inside a bathtub, or other comparatively wide flat surface or gently curved surface is first described. In this case, as illustrated in FIG. 2, the surface 201 of the bathtub can be cleaned by pushing the entirety of the first cleaning surface 101 against the surface 201 while grasping the left and right side surfaces 4 and 5 of the thick part 1 of the sponge scrubber 100 with the thumb and pinky or ring finger and pushing the tip of the index finger or middle finger against the upper surface 20 of the thin part 2. When the sponge scrubber 100 is used in this manner, it is easy to grasp because the thick part 1 is grasped, and it is excellent in feel when used. The wide area can be easily cleaned because the surface 201 of the bathtub is cleaned using the entire surface of the flat first cleaning surface 101.

As illustrated in FIG. 3, the surface 201 of the bathtub can also be cleaned by turning the sponge scrubber 100 front to rear and grasping the thin part 2 of the sponge scrubber 100. In this case, the first cleaning surface 101 can be pushed closely against the surface 201 of the bathtub and the operation of the cleaning operation is easy even without exerting a great force to the fingertips, because the tips of the index finger and middle finger are pushed against the upper surface 10 of the comparatively highly rigid thick part 1. When dirt adheres to the first cleaning surface 101, the surface 201 of the bathtub can be cleaned with the second cleaning surface 102 by turning over the sponge scrubber 100 top to bottom and grasping the side of the first cleaning surface 101 as illustrated in FIG. 4. In this case, the palm and fingers are pushed against the first cleaning surface 101 and a compression force is applied to the sponge scrubber 100, whereby the sponge scrubber 100 is deformed and the second cleaning surface 102 (upper surfaces 10 and 20 and inclined surface 30) becomes nearly flat. The surface 201 of the bathtub can thereby be cleaned with both surfaces (first cleaning surface 101 and second cleaning surface 102) of the sponge scrubber 100, and the entirety of the sponge scrubber 100 can be used for efficient cleaning.

The case when cleaning a corner part 202 where a side surface and a bottom surface of the bathtub intersect is next described. In this illustrated in FIG. 5, the thick part 1 of the sponge scrubber 101 is grasped, a finger is pushed against the upper surface 20 of the thin part 2, and the thin part 2 is bent following the corner part 202. Because the thin part 2 is low in rigidity, the thin part 2 can be deformed following the corner part 202 without applying so great a force, and cleaning of the corner part 202 is easy. The thin part 2 can easily bend from a base (intersection with the inclined surface 30) thereof. Therefore, whether the radius of curvature of the corner part 202 is small or whether the radius of curvature is large, the entire area of the corner part 202 can be covered with the thin part 2 and the corner part 202 can be efficiently cleaned.

The case when cleaning parts other than a bathtub, for example, a shower hose 203, is finally described. In this C iSC, ciS illustrated in FIG. 6, the thick part 1 is grasped and the front end of the thin part 2 is bent by a finger, the outer perimeter surface of the shower hose 203 is covered by the thin part 2, and the outer perimeter surface of the shower hose 203 is cleaned with the thin part 2. The same sponge scrubber 100 can thereby be used to clean not only a bathtub, but also fine parts including a shower hose 203, a handrail, a rack, or around a faucet, and the scope of application of the sponge scrubber 100 is widened.

The sponge scrubber 100 of the first embodiment has a thick part 1 having an upper surface 10 and a lower surface 11 facing opposite the upper surface 10, and a thin part 2 having an upper surface 20 and a lower surface 21 facing opposite the upper surface 20, and being connected to the thick part 1. The thickness H2 between the upper surface 20 and the lower surface 21 of the thin part 2 is thinner than the thickness HI between the upper surface 10 and the lower surface 11 of the thick part 1. The lower surfaces 11 and

21 are a continuous flat surface. The upper surface 10 and 20 are connected by the inclined surface 30.

By this configuration, for example, when cleaning a corner part 202 of a bathtub, the thin part 2 of the sponge scrubber 100 can easily deform following the corner part 202 and cleaning of the corner part 202 is easy. Also, both the first cleaning surface 101 on the lower side and the second cleaning surface 102 on the upper side can be used for cleaning of the bathtub, and the cleaning operation can be accomplished efficiently. The thin part 2 bends following the outer perimeter surface of the shower hose 203, and therefore can be used for cleaning of the shower hose 203 and other fine parts. That is, the sponge scrubber 100 according to the present embodiment is ideal for efficiently cleaning all kinds of places.

Because the upper surface 10 of the thick part 1 is configured as a flat surface parallel with the lower surface 11 and the upper surface 20 of the thin part 2 is configured as a flat surface parallel with the lower surface 21, the thick part 1 comes to have a fixed thickness across the front-rear direction and the sponge scrubber 100 is easy to grasp. The thin part 2 also comes to have a fixed thickness across the front-rear direction, the entirety of the thin part 2 can be easily bent from the base of the thin part 2, and a favorable ability to follow curved surfaces is obtained.

A favorable ability to follow curved surfaces and ability to follow the undersurface are obtained when the value of the ratio of the thickness HI of the thick part 1 over the thickness H2 of the thin part 2 is set to about 1.3 or higher and about 7 or lower.

Furthermore by setting the thickness H2 of the thin part 2 to about 10 mm or higher and about 30 mm or lower, the thickness of the entirety of the sponge scrubber 100 can be set to an optimal thickness being excellent in feel when used, while assuring the ability to follow curved surfaces and the ability to follow the undersurface.

When the value of the ratio of the length L2 of the thin part 2 over the total length L of the sponge scrubber 100 from one end (rear end surface 7) on the side of the thick part to the other end (front end surface 6) on the side of the thin part is set to about 0.1 or higher and about 0.8 or lower, a favorable ability to follow curved surfaces and ability to follow the thin part can be obtained and cleaning of the outer perimeter surface of the shower hose 203, or the like, can be accomplished easily.

A favorable ability to follow curved surfaces and ability to follow the undersurface is obtained when the angle formed by the extended surface extending the upper surface 20 of the thin part 2 rearward and the inclined surface 30 is set to about 10° or higher and about 70° or lower.

A second embodiment of the sponge scrubber of the present invention is described while referring to FIG. 9. Differences from the first embodiment are mainly described in the following. A difference in the sponge scrubber of the second embodiment from the sponge scrubber of the first embodiment is that the entirety of the sponge scrubber is covered by a net. The sponge scrubber per se (hereinafter referred to as "sponge scrubber body") covered by the net is the same as the sponge scrubber 100 in the first embodiment.

FIG. 9 is a perspective view illustrating the configuration of the sponge scrubber 300 according to the second embodiment. The same reference numerals are assigned to the same places as in FIG. 1. The sponge scrubber 300 has a sponge scrubber body 100 made of urethane foam and a net 301 covering the entirety of the sponge scrubber body 100. The net 301 is formed, for example, by weaving in nylon, polyester, polyethylene terephthalate, polypropylene, or other resin fiber.

The net 301 can be formed using a single kind of fiber, but may also be formed using a plurality of fibers having different functions. Specifically, for example, the net 301 may be formed by weaving in a flat yarn containing polyethylene terephthalate or other plastic that efficiently removes soap scum and other highly bulky dirt, and a yarn containing nylon, polyester, polypropylene, acrylic, or other resin fiber that expresses an ability to clean dirt such as skin oil that cannot be scrubbed off without bringing the cleaning utility into close contact with the surface to be cleaned. All kinds of dirt can be easily cleaned by thus having a material on the surface of the sponge scrubber 300, such as a net 301. Microfiber may also be used as resin fiber. A higher cleaning ability can be obtained because the minute fibers of the microfiber scrub off the dirt.

The weaving method is not particularly limited. The weaving method is not limited to those used with various kinds of net sponges for kitchen use, and the weaving method is not limited provided that the net can be used as a wiping member. The weaving method also does not have to be uniform for the entirety of the net; the weaving method can be changed according to the location, and the fiber used can be changed according to the location. The net 301 is not limited to being one by a weaving method that configures a flat surface with an aggregation of loops, and can also be configured as a flat- woven or other fabric.

For example, the net 301 is formed by circular knitting into a cylindrical form, and is configured in a bag form with one end closed and the other end open. The net 301 and the sponge scrubber body 100 can be integrated by inserting the sponge scrubber body 100 from the opening of the bag form and sewing the opening. The sponge scrubber body 300 thus completed has seams in the left-right direction on the front end and the rear end. There is no limitation to the shape of the net or the place of the seam. A flat sheet-form net can be formed, and moreover a seam can be formed on a side surface part of the scrubber body 100.

Furthermore, the sponge scrubber 300 may have a seam 303 where the upper surface and the lower surface of the net 301 are sewn together across a prescribed length in the left-right direction running through the sponge scrubber body 100 at a place (the base of the thin part 2) of intersection between the upper surface of the thin part 2 and the inclined surface 30 of the sponge scrubber body 100. Tension thereby acts on the net 301 and the net 301 can be made to adhere nearly as close as possible to the surface of the sponge scrubber body 100 across the entire area including the inclined surface of the sponge scrubber body 100. The shape of the sponge can thereby be clearly visible from the outside even when being covered by the net. That is, the net 301 comes to cover the entirety of the thick part 1 and the thin part 2 across the upper surface 10 of the thick part 1, the upper surface 20 of the thin part 2, and the inclined surface 30 of the sponge scrubber body 100. Accordingly, slipping of the net 301 from the sponge scrubber body 100 during use can be prevented, and a netted sponge scrubber 300 excellent in feel when used can be configured. Also, the fingers can be easily placed and the sponge scrubber body 100 can be easily bent due to the presence of impressions of the seam 303. With the sponge scrubber of the second embodiment as described above, the cleaning function can be further improved by covering the entirety of the sponge scrubber with a net.

The sponge scrubbers 100 and 300 according to the above embodiments furthermore are capable of various kinds of deformation. For example, various kinds of members containing different materials from urethane foam, for example, a nonwoven cloth containing an abrasive agent, or a mesh, film, cloth, or other foam layer, may be affixed on at least one surface of the first cleaning surface 101 and the second cleaning surface 102 of the sponge scrubber 100. The sponge scrubber 100 may be configured as a multilayer structure having a plurality of foam layers having different colors or hardness, or as combined with a layer of material different from urethane foam as stated above.

The sponge scrubber may have any and all kinds of shapes, provided that: the thick part 1 as the first part has an upper surface 10 (first surface) and a lower surface 11 (first opposite surface) facing opposite the upper surface 10; the thin part 2 has an upper surface 10 (second surface) and a lower surface 21 (second opposite surface) facing opposite the upper surface 20; a thickness HI (first thickness) between the upper surface 10 and the lower surface 11 is thicker than a thickness H2 (second thickness) between the upper surface 20 and the lower surface 21; the lower surface 11 and the lower surface 21 form a continuous flat surface; and the upper surface 10 and the upper surface 20 are connected by an inclined surface 30. That is, although the upper surface 10 and the lower surface 11 of the thick part 1 are formed as parallel flat surfaces and the upper surface 20 and the lower surface 21 of the thin part 2 are formed as parallel flat surfaces, the upper surfaces 10 and 20 and the lower surfaces 11 and 21 may be not parallel. For example, the upper surfaces 10 and 20 may be formed in a wavy shape, or may be formed in a shape inclined in the front-rear direction. When the upper surfaces 10 and 20 are inclined, the angle of inclination thereof is smaller than the angle of inclination Θ of the inclined surface 30.

A removable handle may be attached to the sponge scrubber, and the sponge scrubber may be used grasping the handle. For example, a rod-form handle may be placed protruding from the rear surface 7 of the sponge scrubber 100 such as in a toilet scrubber. A handle may be provided on the upper surface 10 of the sponge scrubber 100 such as in a hand-held mop. For example, an indentation having a prescribed length in the width direction may be provided in the center in the width direction of the base of the thin part 2 of the sponge scrubber 100 in order to make the sponge scrubber easy to bend. An indentation having a prescribed length in the front-rear direction may be provided, and an indentation inclining in the front-rear direction may be provided.

The sponge scrubber may be formed in a symmetrical shape in the front-rear direction, by providing a thick part 1 in the center in the front-rear direction of the sponge scrubber 100 and providing thin parts 2 respectively, interposing inclined parts 3, from the front and rear ends of the thick part 1. The entirety of the sponge scrubber may be formed in a disk form by providing a thick part 1 in the center and a thin part 2 around the entirety of the perimeter thereof. In this case, the entire sponge scrubber may be formed in a doughnut form by providing a circular through-hole running through the up-down direction in the center of the thick part 1.

In the above embodiments, the lower surfaces 11 and 21 (first cleaning surfaces

101) of the sponge scrubber 100 are formed as a continuous flat surface. Here, "flat surface" includes not only a flat surface in the sense of having no unevenness, but also a flat surface configured so that the thickness of the sponge scrubber is not changed as a whole. Accordingly, a wave-type or other uneven part may be formed across the entirety of the first cleaning surface 101, and an embossed pattern may be formed. An uneven part may be formed across the entirety of the second cleaning surface 102 instead of the first cleaning surface 101, or may be formed on both the first cleaning surface 101 and the second cleaning surface 102.

At least any of the corners of intersection of the upper and lower surfaces 10, 11, 20, and 21, left and right side surfaces 4 and 5, and front and rear surfaces 6 and 7 of the sponge scrubber 100 may be formed in an arc form. A constricted part having a prescribed length may be provided going forward from the rear surface 7 in the center in the up-down direction of the left and right side surfaces 4 and 5 of the thick part 1. In the above embodiments, the sponge scrubbers 100 and 300 are rectangular in plan view, but may be formed as another shape. In the above embodiments, the thickness of the sponge scrubber includes two levels, providing a thick part 1 and a thin part 2 on the sponge scrubber 100, but the thickness of the sponge scrubber 100 may include three or more levels, providing an intermediate part thinner than the thickness HI of the thick part 1 and thicker than the thickness H2 of the thin part 2 between the thick part 1 and the thin part 2.

The case when the sponge scrubber is used mainly in a bathroom has been described above, but the sponge scrubber of the present invention is not limited only to bathrooms, and can be used in all kinds of places, including kitchens and outdoors. The sponge scrubber also is not limited to cleaning of bathtubs or shower hoses, and can be used for cleaning eating utensils and the like.

Examples

Tests were carried out concerning the ease of deformation of sponge scrubbers having various shapes. The results of the tests are described. Four kinds of sponge scrubbers were used for the tests: the sponge scrubber 100 according to the present embodiment; a solid rectangular (rectangular in side view) sponge scrubber 100 as illustrated in FIG. 7A (Comparative Example 1); a triangular columnar (triangular in side view) sponge scrubber 120 as illustrated in FIG. 7B (Comparative Example 2); and a sponge scrubber 130 having removed the inclined part 3 from the sponge scrubber 100 according to the present embodiment as illustrated in FIG. 7C (Comparative Example 3).

The first cleaning surface 101 and the second cleaning surface 102 of the sponge scrubbers 110, 120, and 130 in the comparative examples are defined as illustrated. That is, the surface used for ordinary cleaning is defined as the first cleaning surface 101, and the surface on the opposite side of the first cleaning surface 101 is defined as the second cleaning surface 102. The width W, total length L, and maximum thickness HI of each sponge scrubber 100, 110, 120, and 130 are mutually equal, being W = 85 mm, L = 148 mm, and HI = 50 mm. Each sponge scrubber 100, 110, 120, and 130 was configured using the mutually same material (urethane foam having a hardness of 115 N).

The above sponge scrubbers 100, 110, 120, and 130 were subjected to three kinds of tests: a curved surface following test, an undersurface following test, and a bending test. In the curved surface following test, as illustrated in FIG. 8A, each sponge scrubber (the sponge scrubber 100 in the drawing) was placed upright at a prescribed angle (70°) in a container 204 having a corner part having a prescribed radius of curvature (R 12 mm), and in this state the sponge scrubber was pushed in by a prescribed amount (80 mm) as indicated by the arrow in the drawing. The ability to follow corner parts by deformation of the sponge scrubber at this time was evaluated. This was noted as "F" for followed when the first cleaning surface 101 deformed following the corner part as indicated by the dotted line in FIG. 8A; otherwise this was noted as "DNF" for "did not follow."

In the undersurface following test, as illustrated in FIG. 8B, each sponge scrubber (the sponge scrubber 100 in the drawing) was placed on top of a flat surface 205 of a test stand with the second cleaning surface 102 side turned down, and a prescribed load P (20 N) was applied from above as indicated by the arrow in the drawing. At this time, it was noted as "F" for followed when the second cleaning surface 102 of the sponge scrubber adhered closely to the surface 205 as indicated by the dotted line in FIG. 8B; otherwise it was noted as "DNF for "did not follow." In the bending test, a load was applied from above to a place toward the rear of the sponge scrubber by a prescribed length (20 mm) from the front end of each sponge scrubber, the sponge scrubber was pushed in by a prescribed amount (60 mm), and the maximum load at that time was recorded. It was generally considered as easily bent when the maximum load was less than 5 N. The results are shown in Table 1.

Table 1

Tests were next carried out with length, thickness, and angle of inclination as parameters in order to obtain the optimal values of length, thickness, and angle of inclination of the sponge scrubber 100 according to the present embodiment. The results of the tests are described. The material of the sponge scrubber 100 used in the experiments was urethane foam having a hardness of 115 N, which is commonly used for bathtubs.

Table 2 shows the results of curved surface following tests, undersurface following tests, and bending tests after changing the thickness HI of the thick part 1 and the thickness H2 of the thin part 2 to various values. The curved surface following test was carried out with respect to a curved surface having a radius of curvature of 22 mm, imagining a corner part of a bathtub. The total length L of the sponge scrubber 100 used in the experiments was 148 mm, the width W was 85 mm, the length LI of the thick part was 64 mm, the length L of the thin part 2 was 44 mm, and the length L3 of the inclined part 3 was 40 mm. The thickness HI of the thick part 1 was set for each 10 mm within a range suited for use (20 mm to 80 mm). Curved surface following tests, undersurface following tests, and bending tests were carried out with respect to a sponge scrubber in which the thickness HI of the thick part 1 was 40 mm. Only curved surface following tests and undersurface following tests were carried out with respect to sponge scrubbers in which the thickness HI of the thick part 1 was 20 mm, 30 mm, 50 mm, 60 mm, 70 mm, and 80 mm. Table 2

As shown in Table 2, the ability to follow curved surfaces and the ability to follow the undersurface were favorable when the thickness HI of the thick part 1 was 20 mm to 70 mm and when the thickness H2 of the thin part 2 was in a range of 10 mm to 30 mm. A favorable effect was obtained also in the bending test when the thickness HI of the thick part 1 was 40 mm and the thickness H2 of the thin part 2 was in a range of 10 mm to 30 mm. By these results, the thickness H2 of the thin part 2 was particularly 10 mm to 30 mm. The thickness H2 was more particularly 15 mm to 25 mm in order to assure a stable ability to follow curved surfaces and ability to follow the undersurface.

The value of the ratio (H1/H2) of the thickness HI of the thick part 1 to the thickness H2 of the thin part 2 was 1.3 to 7. The value of the ration was more particularly 1.3 to 4, considering that it is easiest to grip when the thickness HI of the thick

Table 3 shows the results of curved surface following tests and thin part following tests carried out changing the total length L of the sponge scrubber and the length L2 of the thin part 2 to various values. A thin part following test is an experiment to confirm whether an outer perimeter surface of a shower hose 203 can be covered by the thin part 2 as illustrated in FIG. 6. It was noted as "C" for covered when covering was possible; it was noted as "CNC" for "could not cover" when covering was not possible. The width W of the sponge scrubber 100 used in the experiments was 85 mm, the length LI and the thickness HI of the thick part 1 were 64 mm and 40 mm, the thickness H2 of the thin part 2 was 20 mm, and the length L3 of the inclined part 3 was 40 mm. The total length L was set in a range of 55 mm to 230 mm, and the length L2 of the thin part 2 was set in a range of 10 mm to 190 mm.

Table 3

As shown in Table 3, favorable effects are obtained in both the curved surface following tests and the thin part following tests except in the cases when the total length L is 113 mm and the length L2 of the thin part 2 is 10 mm. By these results, the value of the ratio (L2/L) of the length L2 of the thin part 2 to the total length L is 0.1 to 0.8. Furthermore, L2/L is more particularly 0.2 to 0.7 when considering that the sponge scrubber 100 is hard to grip when the length LI of the thick part 1 is too short and that the sponge scrubber 100 is poor in maneuverability and hard to handle when the total length L is too long.

Table 4 shows the results of curved surface following tests and undersurface following tests changing the angle of inclination Θ of the inclined surface 30 of the sponge scrubber 100 to various values. The width W of the sponge scrubber 100 used in the experiments was 85 mm, the length LI and the thickness HI of the thick part 1 were 64 mm and 40 mm, and the length L2 of the thin part 2 was 44 mm. The length of the inclined part 3 was set to a range of 0 to 185 mm, and the angle of inclination Θ at this time is set to a range of 10° to 90°.

Table 4

As shown in Table 4, a favorable effect was not obtained in the test of ability to follow the undersurface when the angle of inclination Θ was 72° or greater. Meanwhile, a favorable effect was obtained in the curved surface following test and the undersurface following test when the angle of inclination Θ was 68°. A favorable ability to follow also was obtained in the curved surface following test and the undersurface following test when the angle of inclination Θ was 10°. From these results, the angle of inclination Θ is 11° to 70°. The ability to follow the undersurface is as high as the angle of inclination Θ is small, but the angle of inclination Θ is particularly 20° to 50° considering that the total length L of the sponge scrubber 100 becomes longer as the angle of inclination Θ becomes smaller.

The above description is just one example, and the present invention is not limited by the above embodiments and modifications provided that the characteristics of the present invention are not impaired. The configurative elements of the above embodiments and modifications include those that can be substituted and are obviously substituted while maintaining the unity of the present invention. That is, other modes that can be imagined within the scope of the technical concept of the present invention are included in the scope of the present invention. One or a plurality of the above embodiments and modifications can also be optionally combined.