Blower pipe

Abstract

To provide a blower pipe capable of securely connecting two pipes while simplifying a shape of a connection part of the pipes, and reducing manufacturing costs.SOLUTION: A blower pipe 2 is such that: an intermediate pipe 2B (second pipe) is formed with a circumferential direction restriction groove part 20 and an axial direction restriction groove part 30; and the outer peripheral surface of a base pipe 2A (first pipe) is formed with a first projection part 60 and a second projection part 70. The base pipe 2A and the intermediate pipe 2B are connected in a state where the tip of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B, the first projection part 60 is engaged with the circumferential direction restriction groove part 20 in the circumferential direction of the intermediate pipe 2B, and the second projection part 70 is engaged with the axial direction restriction groove part 30 in the axial direction of the intermediate pipe 2B.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a blower pipe. [Background technology]

[0002] In a power blower (blowers) used for tasks such as cleaning up fallen leaves and dust, a blower pipe is connected to the outlet formed in the housing to direct the high-speed airflow emitted from the outlet toward the desired location. The blower pipe is configured to be a desired length by connecting multiple pipes.

[0003] An example of a connecting structure for connecting the second pipe to the tip of the first pipe in the blower pipe will now be described. The second pipe has an inner peripheral surface formed with a groove extending in the circumferential direction, and the inner surface of the groove has an uneven surface. The first pipe has an outer peripheral surface at its tip end with a protrusion.

[0004] When connecting the two pipes, the tip of the first pipe is inserted into the base end opening of the second pipe, and the second pipe is rotated circumferentially relative to the first pipe, so that the protrusion of the first pipe fits into the groove of the second pipe and the tip of the first pipe abuts against the reduced diameter portion of the inner circumferential surface of the second pipe.

[0005] The tip of the first pipe abuts the reduced diameter portion of the second pipe, and the protrusion of the first pipe engages with the groove of the second pipe, restricting axial movement of both pipes. Furthermore, the protrusion of the first pipe engages with the uneven surface of the groove of the second pipe, restricting circumferential movement of both pipes. In this way, the axial and circumferential movement of both pipes is restricted, thereby connecting the two pipes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 8,210,577 Summary of the Invention [Problem to be solved by the invention]

[0007] In the above-described connection structure, a large number of grooves are arranged in the axial direction of the second pipe. That is, the grooves are formed in multiple stages in the axial direction, and each groove has a large number of projections and recesses formed in the circumferential direction. By arranging a large number of grooves and recesses in the axial and circumferential directions of the pipes in this way, even if the pipes have dimensional errors in the axial or radial directions, the protrusions of the first pipe can be inserted into any of the grooves of the second pipe, allowing the two pipes to be connected. On the other hand, in the above-mentioned connection structure, the shape of the connection portion of the second pipe becomes complicated, and in addition, the connection structure is located at a position separated from the end of the pipe, so injection molding is difficult to select as a manufacturing method for the pipe, and blow molding is selected. In this way, the complicated structure of the mold for manufacturing the pipe not only directly affects costs, but also limits the options for manufacturing the pipe, which limits the reduction of manufacturing costs.

[0008] SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a blower pipe that can reliably connect two pipes while simplifying the pipe connection structure and reducing manufacturing costs. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides a blower pipe connected to an air discharge port formed in a power blower, the blower pipe comprising: a first pipe; and a second pipe connected to a tip end of the first pipe. The second pipe is formed with a circumferential restriction groove and an axial restriction groove, and the outer circumferential surface of the first pipe is formed with a first protrusion inserted into the circumferential restriction groove and a second protrusion inserted into the axial restriction groove. The tip end of the first pipe is inserted into a base end opening of the second pipe, and the first pipe and the second pipe are connected in a state in which the first protrusion engages with the circumferential restriction groove in the circumferential direction of the second pipe and the second protrusion engages with the axial restriction groove in the axial direction of the second pipe. [Effects of the Invention]

[0010] In the blower pipe of the present invention, the connecting structure between the first pipe and the second pipe is provided with a circumferential restricting portion and an axial restricting portion separately, thereby enabling the connecting structure to be made smaller and simpler. When the first pipe and the second pipe are connected, the second protrusion engages with the axial restricting groove, thereby restricting axial movement of both pipes. Furthermore, the first protrusion engages with the circumferential restricting groove, thereby restricting circumferential movement of both pipes. In this way, in the blower pipe of the present invention, the axial direction restriction groove restricts the axial movement of both pipes, so the structure of the circumferential direction restriction groove can be simplified. Furthermore, in the blower pipe of the present invention, by extending a single circumferential direction restriction groove in the axial direction rather than providing multiple circumferential direction restriction grooves in the axial direction, it is possible to accommodate dimensional errors in the pipes in the axial direction. This simplifies the pipe connection structure while ensuring ease of pipe manufacturing. In the blower pipe of the present invention, the pipe connection structure is simplified while taking into consideration the dimensional errors of the pipes, and the two pipes can be reliably connected. Therefore, in the present invention, the pipes can be easily formed, and the manufacturing cost of the blower pipe can be reduced. For example, the blower pipe of the present invention can be manufactured by injection molding because the structure of the mold for injection molding the pipe is simplified, thus broadening the options for pipe molding methods and allowing for the selection of lower cost manufacturing methods. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a power blower equipped with a blower pipe according to an embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view showing a blower pipe connection structure according to an embodiment of the present invention, as viewed from the tip end side, showing a state in which both pipes are connected. [Figure 3] FIG. 1 is a perspective view showing a blower pipe connection structure according to an embodiment of the present invention, seen from the tip end side, showing a state before both pipes are connected. [Figure 4] FIG. 1 is a perspective view showing a blower pipe connection structure according to an embodiment of the present invention, seen from the base end side, showing a state before both pipes are connected. [Figure 5] 1 is a side view showing a blower pipe connection structure according to an embodiment of the present invention, illustrating a state before both pipes are connected. FIG. [Figure 6] FIG. 10 is a side view showing a blower pipe connection structure according to another embodiment of the present invention, illustrating a state before both pipes are connected. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the blower pipe 2 of this embodiment is attached to a power blower 1 (blower). Power blower 1 generates an airflow within housing 1a by rotating a fan (not shown) housed within housing 1a using a power source (not shown) such as an engine or a motor. Housing 1a is formed with outlet 1b for discharging the airflow, and outlet 1b is connected to blower pipe 2. Then, by blowing the airflow from the tip of blower pipe 2 onto the ground, fallen leaves and dust can be blown away.

[0013] The blower pipe 2 of this embodiment is formed to have a desired length by connecting three pipes: a base pipe 2A, an intermediate pipe 2B, and a tip pipe 2C. Generally, backpack-type power blower 1, such as the one shown in Figure 1, uses three connected pipes because the housing 1a (blower) is far from the ground. Handheld power blowers, on the other hand, use two connected pipes because the housing (blower) is close to the ground. However, even with backpack-type power blower 1, if it is desired to use the outlet 2D at the tip of blower pipe 2 away from the ground, two connected pipes may be used without the third pipe, allowing the worker to select the appropriate method based on the work site.

[0014] The base pipe 2A is a cylindrical resin member whose base end is detachably connected to the discharge port 1b of the housing 1a. A bellows section that is bendable in the radial direction is connected to the base of the base pipe 2A, and the operator uses the flexibility of the bellows section to swing the blower pipe 2, which is located further towards the tip than the bellows section, in a direction suitable for the work. The base end of the intermediate pipe 2B is connected to the tip of the base pipe 2A. The intermediate pipe 2B is a cylindrical member made of resin. The base end of the tip pipe 2C is connected to the tip end of the intermediate pipe 2B. The tip pipe 2C is a cylindrical member made of resin, and has an air outlet 2D formed at the tip of the tip pipe 2C.

[0015] The connection structure between the base pipe 2A and the intermediate pipe 2B is the same as the connection structure between the intermediate pipe 2B and the tip pipe 2C. In the connection structure between the base pipe 2A and the intermediate pipe 2B, the base pipe 2A corresponds to the "first pipe" in the claims, and the intermediate pipe 2B corresponds to the "second pipe" in the claims. In addition, in the connection structure between the intermediate pipe 2B and the tip pipe 2C, the intermediate pipe 2B corresponds to the "first pipe" in the claims, and the tip pipe 2C corresponds to the "second pipe" in the claims.

[0016] In the following description, the connection structure between the base pipe 2A and the intermediate pipe 2B will be described, and the connection structure between the intermediate pipe 2B and the tip pipe 2C will not be described. In the following description, "axial direction" means the extension direction of each pipe, and "circumferential direction" means the circumferential direction of each pipe.

[0017] 3, the inner circumferential surface of the base portion of the intermediate pipe 2B (second pipe) is formed with a reduced diameter portion 10. The reduced diameter portion 10 in this embodiment is a tapered surface in which part of the inner circumferential surface of the base portion of the intermediate pipe 2B is tapered from the base end side toward the tip end side.

[0018] As shown in Fig. 4, two connecting portions 3 each consisting of a circumferential restricting groove portion 20, an axial restricting groove portion 30, and an insertion groove portion 40 are formed in the intermediate pipe 2B in a region closer to the base end than the reduced diameter portion 10. The two connecting portions 3, 3 are formed in positions and shapes that are point-symmetrical with respect to the center point of the base end opening of the intermediate pipe 2B.

[0019] The circumferential restricting groove 20 is disposed at the base end of the intermediate pipe 2B. The circumferential restricting groove 20 extends a predetermined length in the circumferential direction of the intermediate pipe 2B, and also extends a predetermined length in the axial direction from the base end edge of the intermediate pipe 2B toward the tip end. The circumferential direction restricting groove portion 20 is a groove portion recessed toward the outside in the radial direction of the intermediate pipe 2B with respect to the inner peripheral surface of the intermediate pipe 2B. The circumferential direction restricting groove 20 has an open side on the base end side of the intermediate pipe 2B. That is, the base end of the circumferential direction restricting groove 20 is open in the axial direction.

[0020] In this embodiment, two circumferential direction restricting groove portions 20, 20 are arranged on each half of the circumference of the intermediate pipe 2B. The axial length of the connecting structure is, for example, approximately 29 to 71.5 mm, and is set to 42.5 mm in this embodiment. The axial length of the connecting structure in the conventional connecting structure is 105.5 mm, so the connecting structure in this embodiment is significantly shorter.

[0021] As shown in FIG. 5, the circumferential direction restricting groove portion 20 has an axial width that increases from one circumferential end portion 20a toward the other circumferential end portion 20b. In this embodiment, the axial width increases in the direction opposite to the rotation direction A shown in FIG. 5 (from the bottom to the top in FIG. 5). In the circumferential direction restricting groove portion 20, the edge portion on the axial tip side is inclined with respect to the circumferential direction of the intermediate pipe 2B (the up and down direction in Figure 5) so as to displace from the base end side of the intermediate pipe 2B to the tip side (from the right side to the left side in Figure 5) as it moves from one end portion 20a to the other end portion 20b. When connecting the intermediate pipe 2B to the base pipe 2A, the inclination of the edge portion at the tip end of the circumferential regulating groove portion 20 can be used to rotate the intermediate pipe 2B circumferentially relative to the base pipe 2A while also pushing it axially.

[0022] As shown in FIG. 4, the bottom surface of the circumferential direction restricting groove portion 20 (the inner surface on the radially outer side of the intermediate pipe 2B) is formed with an uneven surface 21 in which unevenness is continuously formed in the circumferential direction. The uneven surface 21 is formed by arranging a plurality of recesses recessed into the inner peripheral surface of the intermediate pipe 2B in the circumferential direction, and a protrusion is formed between adjacent recesses, so that the unevenness is continuous. Here, the uneven surface 21 may be provided only on the inner surface by varying the thickness of the bottom of the circumferential direction restricting groove portion 20, but by also providing an uneven surface on the outer surface to match the uneven surface 21 on the inner surface of the intermediate pipe 2B, the thickness of the bottom of the circumferential direction restricting groove portion 20 can be made constant. Note that if an uneven surface is also provided on the outer surface of the intermediate pipe 2B, the intermediate pipe 2B can be rotated by gripping the uneven surface, improving the workability when connecting the base pipe 2A and the intermediate pipe 2B.

[0023] The insertion groove 40 extends in the axial direction from the base end edge of the intermediate pipe 2B toward the tip end side. The insertion groove 40 is a groove recessed radially outward from the inner circumferential surface of the intermediate pipe 2B. The side portion on the base end side in the axial direction of the insertion groove portion 40 is open. That is, the base end portion of the insertion groove portion 40 is open in the axial direction, and is configured so that a second protrusion portion 70 of the base pipe 2A, which will be described later, can enter the insertion groove portion 40 from the base end side.

[0024] 3, the insertion groove 40 is disposed circumferentially spaced apart from one end 20a of the circumferential restriction groove 20. The insertion groove 40 has an axial length greater than that of the circumferential restriction groove 20, and its tip end, which is opposite to the base end in the axial direction, is connected to the axial restriction groove 30, which will be described later. In other words, the insertion groove 40 is a portion that connects the opening at the base end of the intermediate pipe 2B and the circumferential end of the axial restriction groove 30.

[0025] 5, the axial direction restricting groove portion 30 extends in the circumferential direction of the intermediate pipe 2B. The axial direction restricting groove portion 30 is arranged next to the axial tip side of the circumferential direction restricting groove portion 20. The axial direction restricting groove portion 30 is an opening portion that penetrates from the outer peripheral surface to the inner peripheral surface of the intermediate pipe 2B. One end 30a of the axial direction restricting groove 30 is connected to the tip end of the insertion groove 40, and the inside of the axial direction restricting groove 30 and the inside of the insertion groove 40 are in communication with each other. The axial direction restricting groove portion 30 is inclined with respect to the circumferential direction (vertical direction in Figure 5) of the intermediate pipe 2B so as to displace from the base end side to the tip end side (from right to left in Figure 5) of the intermediate pipe 2B as it moves from one end portion 30a on the insertion groove portion 40 side toward the other end portion 30b.

[0026] An inclined edge 31 is formed on the axial base edge (the edge on the right side in FIG. 5) of the axial direction restricting groove 30. The inclined edge 31 is displaced in a stepped manner from one side (the one end 30a side) to the other side (the other end 30b side) in the circumferential direction of the intermediate pipe 2B toward the tip side (the left side in FIG. 5) of the intermediate pipe 2B. In other words, the inclined edge 31 has a plurality of steps. The inclined edge portion 31 has multiple straight portions extending in the radial direction of the intermediate pipe 2B (up and down direction in Figure 5), and inclined portions formed between adjacent straight portions and inclined relative to the straight portions.

[0027] As shown in Figure 3, an abutment portion 50 is formed on the outer surface of the tip of the base pipe 2A (first pipe), which is formed by alternately arranging recessed portions that are recessed around the entire circumference and protruding portions 51 that protrude around the entire circumference in the axial direction. As shown in Figure 2, when the tip of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B, each of the convex portions 51 on the outer surface of the abutment portion 50 of the base pipe 2A abuts against the outer surface of the reduced diameter portion 10 of the intermediate pipe 2B. The outer peripheral surface of the abutting portion 50 is uneven, and the contact area of ​​the abutting portion 50 with the peripheral surface of the reduced diameter portion 10 is small. Therefore, in the process of inserting the base pipe 2A into the intermediate pipe 2B, the tip of the base pipe 2A can be smoothly inserted into the intermediate pipe 2B. Furthermore, when the base pipe 2A is finally fixed to the intermediate pipe 2B, the protrusions 51 are pressed into the inner peripheral surface of the intermediate pipe 2B, so the intermediate pipe 2B and the base pipe 2A are stably connected.

[0028] As shown in FIG. 3, a first protrusion 60 and a second protrusion 70 are formed on the outer peripheral surface of the base pipe 2A at a position closer to the base end than the contact portion 50. Although not shown, other first protrusions 60 and second protrusions 70 are formed on the outer peripheral surface of the base pipe 2A at positions that are symmetrical with respect to the center point of the tip opening of the base pipe 2A with respect to the first protrusions 60 and second protrusions 70 shown in the drawings. In other words, the first protrusions 60 and second protrusions 70 are provided every half circumference of the blower pipe 2 in correspondence with the positions of the circumferential direction restricting grooves 20 and the axial direction restricting grooves 30 provided every half circumference of the blower pipe 2.

[0029] The first protrusion 60 is a portion that is inserted into one end 20a of the circumferential direction restricting groove 20 when the tip end of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B. The first protrusion 60 in this embodiment is formed in a substantially cubic shape. As shown in Figure 5, the axial length of the first protrusion 60 is formed to be significantly smaller than the axial length of one end 20a of the circumferential direction restricting groove portion 20 so that the first protrusion 60 can move axially within the circumferential direction restricting groove portion 20 when the first protrusion 60 is inserted into the circumferential direction restricting groove portion 20.

[0030] The top of the first protrusion 60 is configured to engage with the recess of the uneven surface 21 of the circumferential direction restricting groove 20 in the circumferential direction. When the top of the first protrusion 60 is engaged with the recess of the uneven surface 21 and the intermediate pipe 2B is rotated circumferentially relative to the base pipe 2A, the first protrusion 60 climbs over the convex portion of the uneven surface 21 and moves to the adjacent recess to engage with it.

[0031] The first protrusion 60 can engage with any of the recesses provided in the uneven surface 21 of the circumferential direction restricting groove 20, and the intermediate pipe 2B and the base pipe 2A are most stably connected when the abutting portion 50 provided at the tip of the base pipe 2A is in close contact with the inner circumferential surface of the intermediate pipe 2B and the first protrusion 60 is engaged with a predetermined recess. In this manner, even if there is a manufacturing dimensional error in the outer diameter of the abutting portion 50 of the base pipe 2A and the inner diameter of the intermediate pipe 2B, the first protrusion 60 will engage with any of the recesses provided in the uneven surface 21 of the circumferential direction restricting groove 20 of the intermediate pipe 2B, and the intermediate pipe 2B and the base pipe 2A will be stably connected.

[0032] The second protrusion 70 is disposed closer to the tip end of the base pipe 2A (to the left in FIG. 5) than the first protrusion 60. The second protrusion 70 is the portion that is inserted into the insertion groove 40 when the tip end of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B. As shown in FIG. 3, the second protrusion 70 of this embodiment is formed in a polyhedron having a large width in the circumferential direction.

[0033] As shown in Figure 5, when the second protrusion 70 is inserted up to the tip of the insertion groove 40 and the intermediate pipe 2B is rotated in the rotational direction A relative to the base pipe 2A, the second protrusion 70 moves from the insertion groove 40 into the axial direction restricting groove 30. Furthermore, as the base pipe 2A is inserted into the tip side of the intermediate pipe 2B and the intermediate pipe 2B is rotated in the rotational direction A relative to the base pipe 2A, the base end side of the second protrusion portion 70 abuts against the inclined edge portion 31 of the axial direction regulating groove portion 30. The side surface of the base end of the second protrusion 70 is formed with a corner that fits into the bent portion formed by the linear portion and the inclined portion of the inclined edge 31 .

[0034] Next, a procedure for connecting the intermediate pipe 2B to the base pipe 2A will be described. As shown in FIG. 4, the base end of the intermediate pipe 2B is placed on the tip side of the base pipe 2A, and the tip of the base pipe 2A is inserted into the base end opening of the intermediate pipe 2B. At this time, the circumferential position of the intermediate pipe 2B is adjusted relative to the base pipe 2A so that the first protrusion 60 is inserted into the circumferential restriction groove 20 and the second protrusion 70 is inserted into the insertion groove 40.

[0035] The first protrusion 60 is inserted into the circumferential direction restricting groove 20, and the top of the first protrusion 60 is engaged with the recess of the uneven surface 21. In addition, the second protrusion 70 is inserted into the insertion groove 40. 5, after the intermediate pipe 2B is inserted into the base pipe 2A to a position where the second protrusion 70 is inserted all the way into the tip of the insertion groove 40, the intermediate pipe 2B is rotated in the rotation direction A relative to the base pipe 2A. As a result, the second protrusion 70 enters the axial direction restricting groove 30.

[0036] Furthermore, when the intermediate pipe 2B is rotated in the rotation direction A relative to the base pipe 2A while the base pipe 2A is inserted into the tip side of the intermediate pipe 2B, the abutment portion 50 of the base pipe 2A abuts against the reduced diameter portion 10 of the intermediate pipe 2B, as shown in Figure 2. In addition, the second protrusion 70 abuts against the inclined edge portion 31 of the axial direction restriction groove portion 30. This restricts axial movement of the intermediate pipe 2B relative to the base pipe 2A. Furthermore, the first protrusion 60 engages with the uneven surface 21 of the circumferential direction restricting groove 20, thereby restricting the circumferential movement of the intermediate pipe 2B relative to the base pipe 2A. In this way, the intermediate pipe 2B is fixed to the base pipe 2A in the axial and circumferential directions, thereby connecting the base pipe 2A and the intermediate pipe 2B.

[0037] In the blower pipe 2 described above, as shown in Fig. 5, the axial movement of the base pipe 2A and the intermediate pipe 2B is restricted by the axial direction restricting groove 30 of the intermediate pipe 2B. Because the circumferential direction restricting groove 20 only needs to restrict the circumferential movement of the base pipe 2A and the intermediate pipe 2B, the circumferential direction restricting groove 20 can be formed as a standalone groove in the intermediate pipe 2B. As a result, an axially long uneven surface 21 is formed in the intermediate pipe 2B, which can accommodate axial dimensional errors of the base pipe 2A and the intermediate pipe 2B.

[0038] Therefore, in the blower pipe 2 of this embodiment, the connection structure of the pipes 2A, 2B, 2C shown in FIG. 1 can be simplified, and the pipes 2A, 2B, 2C can be reliably connected. As a result, in the blower pipe 2 of this embodiment, the structure of the mold for injection molding each of the pipes 2A, 2B, 2C can be simplified, and therefore, by manufacturing the blower pipe 2 by injection molding, the manufacturing cost can be reduced.

[0039] Furthermore, as shown in FIG. 3, the axial direction restricting groove portion 30 of the blower pipe 2 of this embodiment is an opening that penetrates the cylindrical portion. Therefore, when injection molding the blower pipe 2, the mold can be removed radially outward from the outer peripheral surface of the cylindrical portion, which simplifies mold movement and reduces manufacturing costs.

[0040] In addition, in the blower pipe 2 of this embodiment, as shown in Figure 4, the circumferential regulating groove portion 20 of the intermediate pipe 2B is arranged at the base end of the intermediate pipe 2B, and the portion on the base end side of the circumferential regulating groove portion 20 is open. With this configuration, when injection molding the blower pipe 2, the mold can be moved in the axial direction relative to the intermediate pipe 2B, so the circumferential direction restricting groove portion 20 can be formed with a simple mold structure. This makes it easier to injection mold the blower pipe 2.

[0041] In the blower pipe 2 of this embodiment, as shown in FIG. 3, the axial direction restricting groove portion 30 of the intermediate pipe 2B is aligned with the circumferential direction restricting groove portion 20 on the tip side in the axial direction. In this configuration, the space of the intermediate pipe 2B can be effectively utilized to arrange the circumferential direction restricting groove portions 20 and the axial direction restricting groove portions 30. This makes it easy to provide a plurality of circumferential direction restricting groove portions 20 and axial direction restricting groove portions 30 in the intermediate pipe 2B.

[0042] When the axial direction restricting groove 30 is disposed closer to the base end in the axial direction than the circumferential direction restricting groove 20, if the axial direction restricting groove 30 is disposed at the base end of the intermediate pipe 2B, the base pipe 2A will come out of the intermediate pipe 2B, and therefore the axial direction restricting groove 30 needs to be disposed a predetermined distance from the base end of the intermediate pipe 2B. Therefore, the cylindrical portion, axial direction restricting groove 30, and circumferential direction restricting groove 20 are disposed in this order from the base end side to the tip end side of the intermediate pipe 2B, and the connecting structure becomes larger in the axial direction. In contrast, when the axial direction restricting groove portion 30 is disposed on the axial tip side of the circumferential direction restricting groove portion 20, as in the present embodiment, the connecting structure can be formed compactly. Furthermore, by positioning the connecting structure closer to the base end side of the intermediate pipe 2B, the overlap length between the base pipe 2A and the intermediate pipe 2B in the axial direction can be shortened, thereby reducing the manufacturing cost and weight of each of the base pipe 2A and the intermediate pipe 2B.

[0043] As shown in FIG. 5, the inclined edge portion 31 of the axial direction restricting groove portion 30 of the intermediate pipe 2B of this embodiment is displaced in a step-like manner. In this configuration, the second protrusion 70 engages with the step portion of the inclined edge portion 31, making it difficult for the second protrusion 70 to shift circumferentially relative to the inclined edge portion 31, and therefore making it difficult for the intermediate pipe 2B to rotate in a direction that disengages it from the base pipe 2A (in the opposite direction to the rotation direction A).

[0044] In the above embodiment, the connection structure between the base pipe 2A and the intermediate pipe 2B shown in Figure 1 is described, but the connection structure between the intermediate pipe 2B and the tip pipe 2C has the same structure and produces the same effects.

[0045] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention. 3, the circumferential restriction groove portion 20 and the axial restriction groove portion 30 of the intermediate pipe 2B are aligned in the axial direction, but the circumferential restriction groove portion 20 and the axial restriction groove portion 30 may also be aligned in the circumferential direction. In this case, the circumferential restriction groove portion 20 and the axial restriction groove portion 30 may each be provided on half the circumference of the intermediate pipe 2B, or the circumference of the intermediate pipe 2B may be divided into 1 / 3 or 1 / 4 of the circumference, etc., to provide many connection points in the circumferential direction of the intermediate pipe 2B. In addition, in this embodiment, the axial regulating groove portion 30 is arranged on the tip side of the intermediate pipe 2B relative to the circumferential regulating groove portion 20, but the circumferential regulating groove portion 20 may also be arranged on the tip side of the intermediate pipe 2B relative to the axial regulating groove portion 30.

[0046] In the blower pipe 2 of this embodiment, the axial direction restricting groove portion 30 is an opening portion, but the axial direction restricting groove portion 30 may be formed by recessing the inner peripheral surface of the intermediate pipe 2B. Furthermore, in the blower pipe 2 of this embodiment, the inclined edge portion 31 of the axial direction restriction groove portion 30 is formed in a stepped shape, but the inclined edge portion 31 may be formed in a linear or arc shape. In the blower pipe 2 of this embodiment, the outer peripheral surface of the tip of the base pipe 2A is formed with a contact portion 50 having a plurality of ring-shaped protrusions 51, but the shape of the contact portion 50 is not limited thereto. For example, it is sufficient that at least one protrusion 51 is formed. Also, a convex portion such as a spiral or a plurality of protrusions may be configured to come into close contact with the inner peripheral surface of the intermediate pipe 2B. The outer peripheral surface of the tip of the base pipe 2A may also be formed flat.

[0047] 6, in another embodiment of the blower pipe 2 of this embodiment, a flexible portion 2E may be formed on the outer peripheral surface of the base pipe 2A, and a first protrusion 60 may be disposed on the outer surface of the flexible portion 2E. Slits S are formed on both edges and the base end edge of the flexible portion 2E. In this way, a part of the edge of the flexible portion 2E is separated from the outer peripheral surface by the slit S, so that the flexible portion 2E can bend radially inward relative to the outer peripheral surface of the intermediate pipe 2B. In this configuration, when the intermediate pipe 2B is rotated circumferentially relative to the base pipe 2A and the first protrusion 60 rides over the convex portion of the uneven surface 21 of the circumferential direction restricting groove portion 20, the first protrusion 60 is pushed radially inward of the intermediate pipe 2B together with the flexible portion 2E. This allows the intermediate pipe 2B to be rotated smoothly circumferentially relative to the base pipe 2A. [Explanation of symbols]

[0048] 1 Power blower 1a Housing 1b Outlet 2 blower pipes 2A Base pipe 2B mid pipe 2C Tip Pipe 2D outlet 10 Reduced diameter part 20 Circumferential direction restricting groove 21 Uneven surface 30 Axial direction restriction groove 31 Sloped edge 40 Insertion groove 50 Contact part 51 Convex part 60 First protrusion 70 Second protrusion

Claims

1. A blower pipe connected to an air outlet formed in a power blower, a first pipe and a second pipe connected to a tip end of the first pipe, The second pipe is formed with a circumferential restriction groove portion and an axial restriction groove portion, The outer circumferential surface of the first pipe is a first protrusion portion inserted into the circumferential direction restricting groove portion; a second protrusion portion that is inserted into the axial direction restriction groove portion, a distal end portion of the first pipe is inserted into a proximal end opening portion of the second pipe; The first protrusion engages with the circumferential direction restricting groove in the circumferential direction of the second pipe, In a state where the second protrusion portion is engaged with the axial direction restriction groove portion in the axial direction of the second pipe, A blower pipe characterized in that the first pipe and the second pipe are connected to each other.

2. 2. The blower pipe according to claim 1, the circumferential direction restriction groove portion and the axial direction restriction groove portion extend in a circumferential direction of the second pipe, The circumferential direction restricting groove portion is recessed toward the outside in the radial direction of the second pipe with respect to the inner circumferential surface of the second pipe, An inner surface of the circumferential direction restricting groove portion is formed with a concave-convex surface in which concaves and convexes are continuously formed in the circumferential direction of the second pipe, In the axial direction restricting groove portion, an inclined edge portion is formed on an edge portion on the base end side of the second pipe, the inclined edge portion being displaced toward the tip side of the second pipe as it moves from one side to the other side in the circumferential direction of the second pipe, a distal end portion of the first pipe is inserted into a proximal end opening portion of the second pipe; the second protrusion abuts against the inclined edge of the axial restriction groove, The blower pipe is characterized in that the first pipe and the second pipe are connected together with the first protrusion engaged with the uneven surface of the circumferential direction restricting groove.

3. 2. The blower pipe according to claim 1, The blower pipe is characterized in that the circumferential direction restricting groove portion and the axial direction restricting groove portion are arranged side by side in the axial direction of the second pipe.

4. 2. The blower pipe according to claim 1, the circumferential direction restricting groove portion is disposed at a base end portion of the second pipe, The blower pipe is characterized in that the circumferential direction restricting groove portion is open at a portion thereof that faces a base end of the second pipe.

5. 2. The blower pipe according to claim 1, The blower pipe is characterized in that the axial direction restricting groove portion is an opening portion that penetrates the cylindrical portion of the second pipe.

6. 3. A blower pipe according to claim 2, The inclined edge portion of the blower pipe is displaced in a stepped manner toward the tip of the second pipe as it moves from one side to the other in the circumferential direction of the second pipe.

7. 2. The blower pipe according to claim 1, the first protrusion is disposed on an outer surface of a flexible portion formed on an outer peripheral surface of the second pipe, The flexible portion has flexibility in a radial direction of the second pipe.

8. 2. The blower pipe according to claim 1, The second pipe has a reduced diameter portion formed by reducing the diameter of an inner circumferential surface of the second pipe, a distal end portion of the first pipe is inserted into a proximal end opening portion of the second pipe; In a state where the tip end portion of the first pipe abuts against the reduced diameter portion of the second pipe, A blower pipe characterized in that the first pipe and the second pipe are connected to each other.

9. 9. A blower pipe according to claim 8, A blower pipe characterized in that at least one protrusion is provided on the outer peripheral surface of the tip end of the first pipe, which abuts against the outer peripheral surface of the reduced diameter portion of the second pipe.

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