Air blowing device

1. An air circulator which is attached to a sheet member and which is for generating an air flow from one side of the sheet member to another side of the sheet member, comprising:

a fan main body; and

a ring member for attaching the fan main body to the sheet member,

wherein:

the fan main body comprises:

a hollow cylinder unit;

a flange which is formed on the hollow cylinder unit so as to protrude from an outer surface of the hollow cylinder unit in a direction approximately orthogonal to the outer surface of the hollow cylinder unit;

a motor fixing unit for fixating a motor;

a wing which is attached to a rotating shaft of the motor; and

first engaging units which are formed on outer surfaces of first parts of the hollow cylinder unit, the first parts forming a pair and facing each other,

the ring member comprises second engaging units which are formed on inner surfaces of second parts of the ring member, the second parts forming a pair and facing each other, and the second engaging units engaging with the first engaging units,

a width between two points on an inner surface of the ring member at the second parts is equal to a width between two points on the outer surface of the hollow cylinder unit at the first parts or is smaller than the width between the two points on the outer surface of the hollow cylinder unit at the first parts,

a width between two points on the inner surface of the ring member at a pair of pressing parts, the pressing parts being two parts which are shifted from the second parts by approximately 90 degrees, is larger than a width between two points on the outer surface of the hollow cylinder unit at two parts which are shifted from the first parts by approximately 90 degrees,

an inner circumference of the ring member is larger than an outer circumference of the hollow cylinder unit,

the ring member is flexible,

the fan main body is attachable to the sheet member by fitting the ring member around the outer surface of the hollow cylinder unit utilizing the flexibility of the ring member so as to make an edge part of the sheet member around an opening formed in the sheet member be held between a back surface of the flange of the fan main body and one end surface of the ring member and to make the first engaging units and the second engaging units engage with each other, and

the fan main body is detachable from the sheet member by squeezing the pair of pressing parts of the ring member so as to make the ring member bend, thereby releasing the engaging of the first engaging units and the second engaging units.

2. The air circulator of claim 1 , wherein each of cross-sections of the hollow cylinder unit and the ring member when cut along a plane orthogonal to a center axis thereof is an approximately rectangular shape.

3. The air circulator of claim 1 , wherein the second engaging units comprise protrusions which are formed on an outer surface of the ring member at the second parts.

4. The air circulator of claim 1 , wherein a length of the inner circumference of the ring member is longer than a length of the outer circumference of the hollow cylinder unit by 1.0% to 3.5% of the length of the outer circumference of the hollow cylinder unit.

5. The air circulator of claim 1 , wherein the first engaging units comprise concaves including engaging walls at lower surfaces thereof and the second engaging units comprise protrusions including engaging walls at lower surfaces thereof, or the first engaging units comprise protrusions including engaging walls at upper surfaces thereof which are formed on the outer surface of the hollow cylinder unit at the first parts and the second engaging units comprise concaves including engaging walls at upper surfaces thereof which are formed on the inner surface of the ring member at the second parts.

6. The air circulator of claim 1 , wherein the first engaging units comprise protrusions including engaging walls at upper surfaces thereof, the protrusions being formed on the outer surface of the hollow cylinder unit at a lower end part at the first parts, and the second engaging units comprise cutouts formed at a lower end part of the ring member at the second parts.

7. The air circulator of claim 1 , wherein a cross-section of the hollow cylinder unit when cut along a plane orthogonal to a center axis thereof is a circle shape and a cross-section of the ring member when cut along a plane orthogonal to a center axis thereof is an oval shape.

8. The air circulator of claim 1 , wherein the first engaging units comprise protrusions which are formed on outer surfaces of parts of the hollow cylinder unit extending downward at the first parts and the second engaging units comprise cutouts formed at parts of a lower end surface of the ring member at the second parts.

9. An air circulator which is attached to a sheet member and which is for generating an air flow from one side of the sheet member to another side of the sheet member, comprising:

a fan main body; and

a ring member for attaching the fan main body to the sheet member,

wherein:

the fan main body comprises:

a hollow cylinder unit;

a flange which is formed on the hollow cylinder unit so as to protrude from an outer surface of the hollow cylinder unit in a direction approximately orthogonal to the outer surface of the hollow cylinder unit;

a motor fixing unit for fixating a motor;

a wing which is attached to a rotating shaft of the motor; and

first engaging units which are formed on outer surfaces of first parts of the hollow cylinder unit, the first parts forming a pair and the first parts facing each other,

the ring member comprises second engaging units which are formed on inner surfaces of second parts of the ring member, the second parts forming a pair and facing each other, and the second engaging units engaging with the first engaging units,

a width between two points on an inner surface of the ring member at the second parts is equal to a width between two points on the outer surface of the hollow cylinder unit at the first parts or is smaller than the width between the two points on the outer surface of the hollow cylinder unit at the first parts,

a width between two points on the inner surface of the ring member at a pair of pressing parts, the pressing parts being two parts which are shifted from the second parts by approximately 90 degrees, is larger than a width between two points on the outer surface of the hollow cylinder unit at two parts which are shifted from the first parts by approximately 90 degrees,

an inner circumference of the ring member is larger than an outer circumference of the hollow cylinder unit,

the ring member is flexible,

outer edge parts of the ring member and a side that faces the flange of the fan main body at the pair of pressing parts are chamfered,

the fan main body is attachable to the sheet member by fitting the ring member around the outer surface of the hollow cylinder unit utilizing the flexibility of the ring member so as to make an edge part of the sheet member around an opening formed in the sheet member be held between a back surface of the flange of the fan main body and one end surface of the ring member and to make the first engaging units and the second engaging units engage with each other, and

the fan main body is detachable from the sheet member by squeezing the pair of pressing parts of the ring member so as to make the ring member bend, thereby releasing the engaging of the first engaging units and the second engaging units.

10. The air circulator of claim 9 , wherein a cross-section of the hollow cylinder unit when cut along a plane orthogonal to a center axis thereof is a circle shape and a cross-section of the ring member when cut along a plane orthogonal to a center axis thereof is an oval shape.

11. The air circulator of claim 9 , wherein each of cross-sections of the hollow cylinder unit and the ring member when cut along a plane orthogonal to a center axis thereof is an approximately rectangular shape.

12. The air circulator of claim 9 , wherein the second engaging units comprise protrusions which are formed on an outer surface of the ring member at the second parts.

13. The air circulator of claim 9 , wherein a length of the inner circumference of the ring member is longer than a length of the outer circumference of the hollow cylinder unit by 1.0% to 3.5% of the length of the outer circumference of the hollow cylinder unit.

14. The air circulator of claim 9 , wherein the first engaging units comprise concaves including engaging walls at lower surfaces thereof and the second engaging units comprise protrusions including engaging walls at lower surfaces thereof, or the first engaging units comprise protrusions including engaging walls at upper surfaces thereof which are formed on the outer surface of the hollow cylinder unit at the first parts and the second engaging units comprise concaves including engaging walls at upper surfaces thereof which are formed on the inner surface of the ring member at the second parts.

15. The air circulator of claim 9 , wherein the first engaging units comprise protrusions which are formed on outer surfaces of parts of the hollow cylinder unit extending downward at the first parts and the second engaging units comprise cutouts formed at parts of a lower end surface of the ring member at the second parts.

16. The air circulator of claim 9 , wherein the first engaging units comprise protrusions including engaging walls at upper surfaces thereof, the protrusions being formed on the outer surface of the hollow cylinder unit at a lower end part at the first parts, and the second engaging units comprise cutouts formed at a lower end part of the ring member at the second parts.