FILTER SHEET AND FILTER

A filter bondable to a grille is provided. The filter is fixable alone to the grille so as not to separate therefrom without using another element such as a hook and loop fastener. The filter is constituted by a filter body and ears integrally connected to the outer edge of the filter body. The filter is bondable to the grille by bringing the filer body into abutment with the front surface of the grille, and bending the ears relative to the filter body until the ears abut against the side surface of the grille. By forming the ears at the filter, and bringing the ears into abutment with the side surface of the grille so as to be bonded thereto, it is possible to increase the attachment strength of the filter relative to the grille, compared to conventional filters each constituted by only a filter body.

TECHNICAL FIELD

The present invention relates to a filter bondable to, e.g., an air vent, and a filter sheet from which the filter can be prepared (cut out).

BACKGROUND ART

Buildings are provided with air vents for ventilation. A cover or grille is attached to the portion of such an air vent on the outer side of a building so as to prevent, e.g., dust from entering the building through the air vent.

Such a grille generally has a louver shape or a mesh shape so as to least interfere with the passage of air through the air vent.

Also, since such a grille cannot catch minute dust or allergens such as pollen and dead ticks, attempts have been made to further increase catching performance by placing a filter made of nonwoven fabric onto the front surface of the grille.

As disclosed in the below-identified Patent Document 1, such a filter includes an adhesive layer on one surface thereof, and is generally fixed to the griller by bringing the adhesive layer into abutment with the front surface of the grille so as to be bonded thereto.

Such a filer is usually sold as a filter sheet including a to-be-cut-out portion defined by an easy break line such as a perforated line so as to be usable for air vents (grilles) different in size or shape. By cutting out the to-be-cut-out portion along the easy break line at home, the to-be-cut-out portion is used as a filter.

Also, such a filter generally has a circular shape, but there are not only round grilles but also grilles of the non-round hood type (boot type). If the shape of the filter does not coincide with the shape of a grille, the filter is appropriately cut and used.

PRIOR ART DOCUMENTS

Patent Documents

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

If a filter is brough into abutment with, and bonded to, the front surface of a grille having, as described above, a louver shape or a mesh shape defining large gaps, the bonded area (contact area) of the filter relative to the grille is small, and thus the filter is likely to separate from the grille.

Therefore, a hook and loop fastener is often used together. For example, a hook and loop fastener is fixed beforehand to the front surface of the grille, e.g., with a double-sided adhesive tape.

In this case, by pushing a filter against the front surface of the grille, the filter is retained on the surface of the grille by not only the adhesiveness of the adhesive layer but also entangled fibers of the hook and loop fastener and the filter. Therefore, separation of the filter is prevented.

However, it is time-consuming to use a hook and loop fastener together with the filter, and fix the fastener to the grille beforehand. Therefore, it is required that a filter be easily fixable alone to a grille so as not to separate therefrom.

Such a problem occurs not only when bonding a filter to an air vent but also when bonding a filter to a different bonding object to be bonded to though which air can pass, e.g., a ventilation fan.

It is an object of the present invention to provide a filter attachable to a bonding object though which air can pass, e.g., an air vent, and a filter sheet for forming the filter, in which the filter can be fixed alone without using a separate member, such as a hook and loop fastener, to the bonding object so as not to be peeled off from the bonding object.

Means for Solving the Problems

In order to achieve the above object, the present invention provides a filter sheet comprising a to-be-cut-out portion which is defined by an easy break line, and which is usable as a filter by being cut out by breaking the easy break line, wherein the to-be-cut-out portion comprises: a filter body; an ear or ears integrally connected to an outer edge of the filter body, and wherein the filter, which is formed by cutting out the to-be-cut-out portion from the filter sheet, is attachable to a bonding object to be bonded to which has a front surface and a side surface, and through which air can pass, by bringing the filer body into abutment with the front surface of the bonding object, and bending the ear or the ears relative to the filter body until the ear or the ears abut against the side surface of the bonding object.

With this arrangement, since the filter is attached to a bonding object by bringing the filter body in abutment with the front surface of the bonding object, and further bending the ear(s) until the ear(s) abuts against the side surface of the bonding object, the attachment strength of the filter relative to the bonding object is high.

Therefore, it is possible to prevent separation of the filter from the bonding object by using the filter alone, without using another element such as a hook and loop fastener, i.e., without attaching such an element to the bonding object in advance.

In the filter sheet of the present invention, it is preferable that the filter body has a substantially circular shape, and the ears are disposed at equal intervals in a circumferential direction of the filter body.

With this shape/arrangement, since the shape of the filter body tends to coincide with the shape of a bonding object such as a general round grille, the filter is convenient in that it is possible to attach the filter to the bonding object without cutting the filter.

Also, since the plural ears are bent until the ears abut against the side surface of the bonding object, the attachment strength of the filter is high. Since the plural ears are disposed at equal intervals in the circumferential direction of the filter body, the attachment strength of the filter is substantially equal in the circumferential of the bonding object, and thus the attached state of the filter is stable.

In the filter sheet of the present invention, it is preferable that the filter body has a rectangular shape having long sides extending in a lateral direction, and the ears are disposed along the long sides of the filter body.

With this shape/arrangement, since the shape of the filter body tends to coincide with the shape of a bonding object such as a horizontally elongated rectangular-shaped air vent of a general central heating system, the filter is convenient in that it is possible to attach the filter to the bonding object without cutting the filter.

Also, since the plural ears are bent until the ears abut against the side surface of the bonding object, the attachment strength of the filter is high.

In the filter sheet of the present invention, the ear or each of the ears preferably includes, at a boundary between the filter body and the ear, a repulsion reducing portion for reducing elastic repulsion of the material of the filter when the ear is bent relative to the filter body.

With this arrangement, since the at least one repulsion reducing portion weakens the repulsive force of the filter formed of, e.g., a nonwoven fabric which is caused by its elasticity, it is possible to prevent the phenomenon in which the bent portions of the filter are gradually restored, and thus the ears are separated from the side surface of the bonding object.

While, as the repulsion reducing portion of the ear or each of the ears at the boundary between the filter body and the ear, various weakening lines such as a half-cut portion are considered, the repulsion reducing portion preferably comprises cuts or easy break portions which can become cuts by being broken when the filter is used, in that the formation is easy and a stable repulsion reducing effect is obtained.

It is preferable that the filter sheet of the present invention further comprises, inside the filter body, a second to-be-cut-out portion comprising: a small filter body defined by a second easy break line; and a small ear or small ears integrally connected to an outer edge of the small filter body, and the second to-be-cut-out portion is usable as a small filter by being cut out by breaking the second easy break line.

With this arrangement, the filter can be cut out and used with respect to a large bonding object, and the small filter can be cut out and used with respect to a small bonding object. In other words, it is possible to selectively use these filters according to the size of the bonding object. Therefore, the filter is convenient in that it is not necessary to adjust the size of the filter, e.g., by cutting the filter by hand at home.

In the filter sheet of the present invention, wherein a position of the small ear or each of the small ears where the small ear or each of the small ears is integrally connected to the small filter body is preferably displaced, in a circumferential direction of the filter sheet, from a position of the ear where the ear is integrally connected to the filter body, or from positions of the ears where the ears are integrally connected to the filter body.

If the position of the small ear or each of the small ears where it is integrally connected to the small filter body coincide, in the circumferential direction of the filter sheet, with the position of the ear where it is integrally connected to the filter body, or from the positions of the ears where they are integrally connected to the filter body, the small ear(s) will be adjacent to the ear(s). Therefore, when cutting out the ear(s), the cut portion of the ear(s) is likely to reach the small ear(s) beyond the easy break line, thus causing the filter to be torn off.

In the present invention, since the integrally connected position of the small ear or each of the small ears relative to the small filter body is displaced from the integrally connected position of the ear or a respective one of the ears relative to the filter body such that the small ear(s) is not aligned with the ear(s), it is possible to reduce tearing of the filter when cutting out the filter.

In the filter sheet of the present invention, one surface of at least the ear or each of the ears is preferably an adhesive layer that allows bonding of the filter to the side surface of the bonding object.

Various methods for attaching the filter to a bonding object are considered, but, if an adhesive layer is formed on the ear(s), it is possible to complete the attachment of the filter with ease, i.e., by simply bending the ear(s) relative to the filter body until the ear(s) is pushed against a bonding object,

The filter sheet is attachable to various bonding objects through which air can pass, e.g., a ventilation fan, and is suitably usable as a filter for an air vent of a building.

In order to achieve the above object, the present invention also provides a filter comprising: a filter body; and an ear or ears integrally connected to an outer edge of the filter body; wherein the filter is attachable to a bonding object which has a front surface and a side surface, and through which air can pass, by bringing the filer body into abutment with the front surface of the bonding object, and bending the ear or the ears relative to the filter body until the ear or the ears abut against the side surface of the bonding object.

Effects of the Invention

Since each of the filter and the filter sheet of the present invention has the above structure, the filter is fixable alone to a bonding object so as not to separate therefrom, and the use of another element such as a hook and loop fastener is not required.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS.1A and1Billustrate a filter sheet1(sheet for a filter) according to an embodiment of the present invention from which a filter10according to the embodiment can be cut out as illustrated inFIG.2. As illustrated inFIGS.3A and3B, the filter10is placed on, and attached to, a grille V installed on a wall surface of a building on the outer side of an air vent. Since the attachment strength is improved as described later, separation of the filter10from the grille V is prevented.

As illustrated inFIG.1A, the entire filter sheet1of the embodiment has a substantially square shape in plan view, and inside the square, a to-be-cut-out portion10(portion which is to be cut out) is defined by a perforated line2as an easy break line. By cutting out the to-be-cut-out portion10by breaking the perforated line2, the to-be-cut-out portion10is used as the filter10of the embodiment.

As illustrated inFIG.1A, the perforated line2comprises a fine perforated line portion extending in the vertical direction (inFIGS.1A and1B) of the filter sheet1, and a coarse perforated line portion extending in the lateral direction (inFIGS.1A and1B) of the filter sheet1.

If the filter is formed of a nonwoven fabric, because there is a difference in breakage strength of the filter between the vertical direction and the lateral direction, originating from the method of producing a nonwoven fabric, if a perforated line is used of which the vertical and lateral perforated line portions are the same in coarseness, a user may not be able to break the perforated line cleanly by hand. However, since the perforated line of the filter of the present invention comprises vertical and lateral line portions that are different in coarseness from each other as described above, when the user tries to break the perforated line2by applying a force in the vertical direction, the breakage strength is substantially the same in the vertical direction and the lateral direction. Therefore, it is possible to prevent e.g., unintended breakage due to, for example, the perforated line not being broken cleanly.

The back surface of the filter sheet1is subjected to an adhesive process to form an adhesive layer3of a specific pattern.

InFIG.1B, as the pattern of the adhesive layer3, a figure of a character is disposed at the center of the filter sheet1; three ring-shapedFIGS.3aare concentrically disposed on the outer side thereof; and a square frame-shaped figure is further disposed on the outer side thereof. Of the three ring-shapedFIGS.3a, the outermost ring merges and is integrated with the square frame-shaped figure at the midpoints of the four sides of the square frame-shaped figure.

Also, chimney-shaped figures radially extend from, of the three ring-shapedFIGS.3a, each of the outermost ring and the innermost ring.

Further, heart-shaped figures are provided spaced apart from each other in, of the three ring-shaped figures, the center ring. Also, a cross-shaped adhesive layer-free portion extends from the center to partially cut out the ring-shapedFIGS.3a, the square frame-shaped figures and the chimney-shapedFIGS.3bof the adhesive layer3.

With the filter10cut out from the filter sheet1and placed on the grille V, no air passes through the adhesive layer3, which is formed by an adhesive process, and air passes through the other filter area, i.e., the area of the filter other than the adhesive layer3. Therefore, the other filter area gradually darkens and discolors due to the adhesion of dust, whereas the adhesive layer3hardly discolors.

Therefore, the color contrast between the adhesive layer3and the other filter area appears over time, and the pattern of the adhesive layer3appears. The degree of the appearance of the pattern can be used as an indicator of the timing of replacement of the filter10.

The adhesive constituting the adhesive layer3is not particularly limited in kind, and may be, e.g., a two-part polyurethane-based adhesive containing a main agent and a curing agent.

The rate of the area of the adhesive layer3relative to the area of the entire back surface of the filter is also not particularly limited, and may be, e.g., 10% to 60%. If this rate is less than 10%, it is difficult to bond the filter10to the grille V, whereas if more than 60%, the adhesive is excessive, thus increasing the cost.

The material of the filter sheet1is not particularly limited, and may be, e.g., a woven fabric, a nonwoven fabric or a porous sheet. Examples of the raw materials of woven and nonwoven fabrics include a natural fiber and a synthetic fiber such as polyester fiber, polyamide fiber or polyimide fiber. A nonwoven fabric made of polyester fiber is preferable in that it has excellent dust catching performance, and can be produced at a low cost. The method for producing a nonwoven fabric is also not particularly limited, and may be, e.g., thermal bonding or spun-bonding.

While the colors of the filter sheet1and the adhesive layer3are not particularly limited, it is preferable that the filter sheet1is white and the adhesive layer3is transparent to make the above-described pattern of the adhesive layer3stand out while the filter is in use.

The filter sheet1may be subjected to an anti-allergen treatment to improve its ability to catch allergens such as pollen and dead ticks.

The size of the filter sheet1is not particularly limited provided that the filter sheet1can completely cover the object to be bonded to (hereinafter referred to as the “bonding object”). If the filter sheet is attached to a grille on an air vent of a building on the outer side thereof, the size of the filter sheet1is preferably 150 mm by 150 mm to 310 mm by 310 mm. If less than 150 mm by 150 mm, the filter which is to be cut out therefrom will be too small to sufficiently cover a general grille, whereas if more than 310 mm by 310 mm, the filter sheet will be too large and a large space for displaying or storing the filter sheet will be required.

The thickness of the filter sheet1is also not particularly limited, but, if a nonwoven fabric is used, this thickness is preferably within the range of 0.5 to 5 mm, and more preferably within the range of 1 to 2 mm.

The weight of the filter sheet1per unit area is also not particularly limited, but if a nonwoven fabric is used, preferably within the range of 20 to 60 g/m2, and more preferably within the range of 30 to 50 g/m2. Within these ranges, the filter can effectively reduce the entry of dust, dirt, etc. from the outside of the building without significantly losing its air permeability.

As illustrated inFIG.1A and1B, andFIG.2, the filter10of the embodiment comprises a filter body11, and four ears12integrally connected to the peripheral edge of the filter body11.

The filter body11has a substantially circular shape in plan view. The position of the filter body11substantially coincides with the positions of the ring-shapedFIGS.3aof the adhesive layer3. Therefore, the filter body11has adhesiveness on its back surface.

The four ears12have a substantially trapezoidal shape in plan view, and are disposed at equal intervals (about 90 degrees) in the circumferential direction of the filter body11.

The ears12extend toward the four corners of the filter sheet1, respectively. The positions of the ears12substantially coincide with the positions of the chimney-shapedFIGS.3bextending from, of the ring-shapedFIG.3aof the adhesive layer3, the outermost ring. Therefore, the ears12have adhesiveness on their back surfaces.

Since, as illustrated inFIGS.1A and1B, the adhesive layer3of the filter sheet1is present on the back surfaces of the filter body11and the ears12, too, the filter10of the embodiment can be bonded to a grille V or the bonding object.

The size of the filter body11is also not particularly limited provided that the filter body11can completely cover the bonding object. If the filter body11is attached to a grille on an air vent of a building on the outer side thereof, the diameter of the filter body11can be set to, e.g., 100 mm to 310 mm.

If less than 100 mm by 100 mm, the filter body will not be able to sufficiently cover the front surface of a grille V having a general size, whereas if more than 310 mm by 310 mm, the filter body may partially protrude beyond the front surface of a grille V having a general size.

The size of each ear12is not particularly limited. For example, the dimension of the ear12in the circumferential direction of the filter body11can be set within the range of 20 mm to 40 mm, and the dimension of the ear12in the radial direction of the filter body11can be set within the range of 10 mm to 30 mm.

If these dimensions are below the above ranges, sufficiently large portions of the ears12may not be able to abut against the side surface of a grille having a general size, when bent. As a result, the retaining forces when the ears12are attached to the side surface may be insufficient, thus causing the filter to fall off. If these dimensions are above the above ranges, the ears12may partially protrude beyond the side surface of a grille having a general size, making it necessary to cut off the excess portions of the ears12.

As illustrated inFIG.1A, the perforated line2, which defines the filter body11, extends, on the boundary between the filter body11and each ear12of the filter10, into the inner side of the ear12.

As illustrated inFIG.2, when cutting out the filter10, by breaking the portions of the perforated line2extending into the inner side of each ear12(easy break portions), too, repulsion reducing portions12aare formed at the ear12.

When bending the ear12at the boundary between the filter body11and the ear12, the repulsion reducing portions12aprevent the return of the ear12to its unbent state due to the restoring elasticity of the material of the filter sheet1.

The formation range of the repulsion reducing portions12a(of each ear12) is not particularly limited. For example, the formation range is preferably 1/5 to 4/5, and more preferably 2/5 to 3/5, of the dimension of the ear12in the circumferential direction of the filter body11, though this depends on the thickness of the filter body11.

If less than 1/5, the formation range is too small to sufficiently reduce the restoring elasticity of the material of the filter sheet1, whereas if more than 4/5, the formation range is too large, thus causing the ear12to be easily torn off from the filter body11.

As illustrated inFIG.1A, the filter sheet1includes, inside the filter body11, a second to-be-cut-out portion20defined by a second perforated line4as an easy break line.

As shown inFIG.2, by cutting out the second to-be-cut-out portion20by breaking the second perforated line4, the second to-be-cut-out portion20is used as a small filter20of the embodiment.

As illustrated inFIG.1A, the second perforated line4comprises, as with the perforated line2, a fine perforated line portion extending in the vertical direction (inFIGS.1A and1B) of the filter sheet1, and a coarse perforated line portion extending in the lateral direction (inFIGS.1A and1B) of the filter sheet1. Therefore, the second perforated line4can be uniformly broken.

As illustrated inFIG.1A,1BandFIG.2, the small filter20of the embodiment comprises a small filter body21, and four small ears22integrally connected to the peripheral edge of the small filter body21.

The small filter body21has a substantially circular shape in plan view.

The position of the small filter body21substantially coincides with the position of, of the ring-shapedFIGS.3aof the adhesive layer3, the innermost ring. Therefore, the small filter body21has adhesiveness on its back surface.

The four small ears22have a substantially trapezoidal shape in plan view, and are disposed at equal intervals (about 90 degrees) in the circumferential direction of the small filter body21.

The small ears22extend toward the midpoints of the four sides of the filter sheet1, respectively. Therefore, the positions of the small ears22where the small ears22are integrally connected to the small filter body21are displaced (by about 45 degrees) from the positions of the respective ears12where the ears12are integrally connected to the filter body11, in the circumferential direction of the filter10and the small filter20. The positions of the small ears22substantially coincide with the positions of the chimney-shapedFIGS.3bwhich extend from the innermost one of the ring-shapedFIGS.3aof the adhesive layer3. Therefore, the small ears22have adhesiveness on their back surfaces.

If the grille to which the filter is to be attached has a small size, instead of the filter10, the small filter20is used by cutting out the small filter20from the filter sheet1.

The size of the small filter body21is not particularly limited provided that the small filter body21is smaller than the filter body11.

The size of each small ear22is not particularly limited, but in order that the bonding performance of the small filter20relative to the grille V is not inferior to that of the filter10, the sizes of the small ear22maybe, e.g., substantially equal to the sizes of the ears12.

As illustrated inFIG.1A, as with the filter10, the second perforated line4, which defines the small filter body21, extends to the inner side of each small ear22on the boundary between the small filter body21and the small ear22of the small filter20.

As illustrated inFIG.2, when cutting out the small filter20, by breaking the portions of the second perforated line4extending to the inner side of the small ear22(easy break portions); too, repulsion reducing portions22aare formed at the small ear22.

When bending the small ear22at the boundary between the small filter body21and the small ear22, the repulsion reducing portions22aprevents the return of the small ear22to its unbent state due to the restoring elasticity of the material of the filter sheet1.

The formation range of the repulsion reducing portions22a(of each small ear22) is not particularly limited. For example, for the same reason as set forth regarding the repulsion reducing portions12a,the formation range is preferably 1/5 to 4/5, and more preferably 2/5 to 3/5, of the dimension of the small ear22in the circumferential direction of the small filter body21. If less than 1/5, the formation range is too small to sufficiently reduce the restoring elasticity of the material of the filter sheet1, whereas if more than 4/5, the formation range is too large, thus causing the small ear22to be easily torn off from the small filter body21.

Having described the structure of the filter sheet1of the embodiment, description is now made, with reference toFIGS.3A to3CandFIGS.4A and4B, of how to use the filter10and the small filter20of the embodiment that are cut out from this filter sheet1.

While how to use the filter10is described in the shown example, the same is true for the small filter20.

First, as illustrated inFIGS.3A to3C, the filter10is moved to a position where the adhesive layer3is opposed to the front surface v1of a grille V on an outer wall surface W of a building; and the filter body11is bonded to the front surface v1of the grille V by bringing the filter body11into abutment with the front surface v1and pressing the filter body11against the front surface v1. The grille V has a flat cylindrical shape, and the shape of its front surface coincides with the shape of the filter body11.

Next, as illustrated inFIGS.4A and4B, the ears12are bonded to the side surface v2of the grille V by bending the ears12relative to the filter body11until the ears12abut against the side surface v2, and pressing the ears12against the side surface v2.

By bonding not only the filter body11but also the ears12to the grille V, it is possible to prevent separation of the filter10from the grille V.

Since the repulsion reducing portions12areduce the repulsive force of the filter material, separation of the ears12from the side surface of the grille V is prevented, and the ears12are kept bonded to the grille.

FIG.5illustrates a filter sheet1(sheet for a filter) according to a different embodiment of the present invention from which a filter10according to the different embodiment can be cut out as illustrated inFIG.6. As illustrated inFIG.7, In a central heating system, i.e., a heating system in which a heat source device is installed at a predetermined place in a building, and heated air is fed to rooms of the building that need heating, from the heat source device through pipes under the floor or in the wall. the filter10is placed on, and attached to, a frame body F of an air vent of each of the rooms that need heating.

The features of the filter sheet and the filter of the different embodiment which are the same as those of the above-described embodiment are not described below.

As illustrated inFIG.5, the entire filter sheet1of the different embodiment has a rectangular shape having long sides extending in the lateral direction in plan view, and includes, inside the rectangle, a to-be-cut-out portion10(portion which is to be cut out) defined mostly by perforated lines2as easy break lines which extend parallel to the long sides of the filter sheet1, respectively.

By cutting out the to-be-cut-out portion10by breaking the perforated lines2, the to-be-cut-out portion10is used as the filter10of the different embodiment.

The portions of the filter sheet1discarded after cutting out the filter10are limited to strip-shaped small pieces of the filter sheet1along its long sides. Therefore, it is possible to effectively use the material and reduce waste.

The back surface (not shown) of the filter sheet1is subjected to an adhesive process to form an adhesive layer of in an appropriate pattern such that the adhesive layer least interferes with the passage of air through the filter sheet.

As illustrated inFIG.6, the filter10of the different embodiment comprises a filter body11, and four ears12integrally connected to the edge of the filter body11.

The filter body11has a rectangular shape having long sides extending in the lateral direction in plan view. The four ears12also have a rectangular shape having long sides extending in the lateral direction in plan view, and are on the long sides of the filter body11and disposed at the four corners of the filter body. Portions of the outer edge of the filter body11and portions of the outer edges of the ears12constitute portions of the outer edge of the filter sheet1.

The filter body11and the ears12have adhesiveness on their back surfaces.

As illustrated inFIG.5, the perforated lines2, which define the filter body11, extend to the inner sides of the ears12on the boundaries between the filter body11and the ears12of the filter10.

As illustrated inFIG.6, when cutting out the filter10, by breaking the portions of the perforated lines2extending to the inner sides of the ears12(easy break portions), too, repulsion reducing portions12aare formed at the ears12.

When bending each ear12at the boundary between the filter body11and the ear12, the repulsion reducing portions12aprevent the return of the ear12to its unbent state due to the restoring elasticity of the material of the filter sheet1.

As illustrated inFIG.7, the filter10of the filter sheet1of the different embodiment, which has the above structure, is moved to a position where the adhesive layer is opposed to an air vent on an inner wall surface W of each room of a building which uses a central heating system; and the filter body11is bonded to the front surface v1of a frame body F attached to the air vent by bringing the filter body11into abutment with the front surface v1and pressing the filter body11against the front surface v1. The frame body F has an extremely flat rectangular parallelepiped shape, and the shape of its front surface f1with a louver coincides with the shape of the filter body11.

Next, as illustrated inFIG.7, the ears12are bonded to the side surface f2of the frame body F of the air vent by bending the ears12relative to the filter body11until the ears12abut against the side surface f2, and pressing the ears12against the side surface v2.

By bonding not only the filter body11but also the ears12to the frame body F of the air vent, it is possible to prevent separation of the filter10from the frame body F.

The repulsion reducing portions12aprevent separation of the ears12from the side surface of the air vent, and the ears12are kept bonded to the frame body.

The ears12may be fixed in position by inserting the ears12into the gap between the inner wall surface and the frame body of the air vent so as to be sandwiched therebetween.

Also, the formation positions and the formation ranges of the ears12are not limited to the shown example. For example, the ears12may be formed along the entire long sides of the filter body11, or formed on the short sides of the filter body11.

Also, while, in this embodiment, the filter10is attached to an air vent of each room of a building which uses a central heating system, the filter10may be attached to an air inlet through which air is introduced from the outside of the building.

FIG.8illustrates a variation of the filter sheet1of the different embodiment.

The filter sheet1of this variation includes, inside the filter body11, a second to-be-cut-out portion20(portion which is to be cut out) defined by a second perforated line4as an easy break line. By cutting out the second to-be-cut-out portion20by breaking the perforated line4, the to-be-cut-out portion20is used as a small filter20of the different embodiment.

The small filter20of the different embodiment comprises a small filter body21, and four small ears22integrally connected to the peripheral edge of the small filter body21.

The small filter body21has a rectangular shape having long sides extending in the lateral direction in plan view. The small ears22have a rectangular shape having long sides extending in the lateral direction in plan view, and are on the long sides of the small filter body21and disposed at portions of the small filter body21other than its four corners. Therefore, the positions of the small ears22where the small ears22are connected to the small filter body21, are displaced from the positions of the ears12where the ears12are integrally connected to the filter body11, in the circumferential direction of the filter10and the small filter20.

The small filter body21and the small ears22have adhesiveness on their back surfaces.

If the air vent to which the filter is to be attached has a small size, instead of the filter10, the small filter20is used by cutting out the small filter20from the filter sheet1.

As with the filter10, the small filter20also has repulsion reducing portions22aat the small ears. When attaching the small filter20to an air vent, each small ear22is bent at the boundary between the small filter body21and the small ear22, but the repulsion reducing portions22aprevent the return of the small ear22to its unbent state.

The above-described embodiments are mere examples in every respect, and the present invention is not limited thereto. The scope of the present invention is indicated by the claims, and should be understood to include all modifications and variations within the scope of the claims and the meaning equivalent thereto.

While the filter sheet1of the embodiment has a square shape in plan view, the shape of the filter sheet1is not limited thereto. For example, the filter sheet1may have a circular shape or a rectangular shape as in the different embodiment.

If the filter sheet1of the embodiment has a rectangular shape, a plurality of to-be-cut-out portions10may be arranged in a row in the direction of the long sides of the rectangular filter sheet so that the plurality of to-be-cut-out portions10can be cut out from the filter sheet1.

While, in the filter sheet1of the embodiment, the to-be-cut-out portion10is defined, and the to-be-cut-out portion20is further defined inside of the to-be-cut-out portion10, the structure of the filter sheet1is not limited thereto. For example, the to-be-cut-out portion10and the to-be-cut-out portion20may be arranged in juxtaposition in the filter sheet1.

Also, a further different to-be-cut-out portion20may be defined inside of the to-be-cut-out portion20of the filter sheet1so that a filter smaller than the small filter20can be cut out.

While, in the embodiment, the adhesive layer3is disposed on one surface of the filter sheet1so that the filter10or the small filter20can be attached to a grille V by bonding, the structure of the filter sheet1is not limited thereto. For example, instead of the adhesive layer3, the filter may be attached to a grille V by a different means, e.g., with a magnet or a hook and loop fastener.

If the adhesive layer3is used, the pattern of the adhesive layer3is not limited to the embodiment provided that the adhesive layer3is disposed at least on the back surfaces of the ears12and the small ears22.

While, in the embodiment, the perforated lines2and4are exemplified as easy break lines, the easy break lines are not limited thereto, and may be, e.g., half-cut lines.

While, in the embodiment, the filter10and the small filter20have a circular shape in plan view, the shapes of the filters are not limited thereto. For example, the filters may have an oval shape, a square shape or a rectangular shape as in the different embodiment. For example, if the grille V has a square shape, a filter10and a small filter20are suitably usable which have a square shape coinciding with the shape of the grille V.

If the shape of the filter10or the small filter20does not coincide with the shape of the bonding object, the shape of the filter may be adjusted by appropriately cutting the filter body11or the small filter body21while leaving the ears12or the small ears22uncut. If, for example, the filter10is cut into four equal parts, it is possible to learn the degree of dirt by checking the heart-shaped figures, which are relatively noticeable in the adhesive layer3. Since, as described above, the adhesive layer3has a cross-shaped adhesive-free portion, it is possible to easily cut the filter10into four equal parts along the adhesive-free portion. Since the filter is cut along the adhesive-free portion, no adhesive adheres to a cutting tool such as scissors.

Since, in the embodiment, the square frame-shaped figure is disposed, as a portion of the adhesive layer3, on the sheet portion of the filter sheet1outside the to-be-cut-out portion10, this sheet portion has adhesiveness on its back surface. Therefore, by cutting the filter sheet to partially include the sheet portion of the filter sheet outside of the to-be-cut-out portion, the cut portion of the sheet portion as well as the filter can be bonded to a bonding object.

While the ears12and the small ears22have a substantially trapezoidal shape in the embodiment, the shapes of the ears are not limited thereto. For example, the ears may have a semicircular shape, a square shape or a triangular shape. Also, ears12or small ears22different in shape may be used.

Also, while four ears12and four small ears22are used in the embodiment, the numbers thereof are not limited to four, and may be not more than 3 or not less than 5. While, in the embodiment, the ears12and the small ears22are disposed at equal intervals, and this is preferable in that the filters can be kept bonded stably, the ears12,22may be disposed at different intervals.

While, in the embodiment, the small ears22are angularly displaced from the ears12, the small ears22may be angularly aligned with the respective ears12.

Also, when the small ears22are angularly displaced from the ears12, the displacement angle is not limited to about 45 degrees as in the embodiment.

While, in the embodiment, the ears12are integral with the filter body11, and the small ears22are integral with the small filter body21, each of the ears12and the small ears22may be a separate member integrally jointed to the filter body11,21by an appropriate means such as welding.

The repulsion reducing portions12aand22aare formed at the ears12and the small ears22ain the embodiment, but may be omitted.

When the repulsion reducing portions12aand22aare formed, they are not limited to the embodiment. For example, the repulsion reducing portions of each ear may be not perforated lines but slit-shaped cuts as illustrated inFIG.9A. Alternatively, the repulsion reducing portions may be notch-shaped cuts having a width as illustrated inFIG.9B.

Also, as illustrated inFIG.10A, a repulsion reducing portion12a,22acomprising a narrow portion (portion with a reduced width) may be formed at each ear12,22or as illustrated inFIG.10B, the narrow portion may be displaced from the center.

The repulsion reducing portions12a,22ado not need to be portions cut beforehand, or portions cut when the filter is used provided that they can reduce the repulsion of the filter material, and they may be half-cut portions which are not cut even when the filter is used.

If the repulsion reducing portions12a,22aare perforated lines, in the embodiment, perforated lines forming the repulsion reducing portions12a,22aare formed on the imaginary line extending from the perforated line2,4, which defines the to-be-cut-out portion10,20. However, the perforated lines do not need to be connected to the perforated line2,4, and may be disconnected or displaced from the perforated line2,4.

While, in the embodiment, a grille V of an air vent is exemplified as the bonding object to which the filter is attached, the bonding object is not limited thereto provided that passage of air is allowed. For example, the bonding object may be a range hood, the inlet/outlet of a ventilation fan, an air vent of a room on the inner side, or an air vent of a bathroom door.

That is, the filter10of the present invention is also usable for bonding objects other than air vents regardless of whether the filter is used outside or inside of a building If the filter is attached to a range hood, the inlet/outlet of a ventilation fan, an air vent of a room on the inner side or an air vent of a bathroom door, the shapes and the sizes of the filter sheet1, the filter10, the small filter20, the ears, etc. can be appropriately set according to such a bonding object, and are not limited to those of the filter sheet1and its elements of the embodiment, which are attached to a grille. Also, if a nonwoven fabric is used, the thickness of the nonwoven fabric and its weight per unit area can be appropriately set according to such a bonding object. For example, if a nonwoven fabric is used for a range hood, the weight of the nonwoven fabric per unit area can be set within the range of 20 to 150 g/m2.

While, in the embodiment, the filter10and the small filter20are used by cutting out these filters from the filter sheet1, a filter10and a small filter20may be used which are in a completed state and do not need to be cut out.

DESCRIPTION OF REFERENCE NUMERALS