Retractable device

Abstract

To provide an expansion device reducing stress generated on two pieces of belts forming a pipe structure by being wound in a spiral state.SOLUTION: An expansion device includes: an expandable pipe structure 100 formed by being wound with a first belt 110 and a second belt 120 arranged to the inside of the first belt 110 around an axis line in a spiral state; a first belt case 10 where parts not forming the pipe structure 100 of the first belt 110 are stored in a vortex state; and a second belt case 20 where parts not forming the pipe structure 100 of the second belt 120 are stored in the vortex state. The first belt case 10 and the second belt case 20 are integrally structured, and a thickness of the first belt 110 is thinner than a thickness of the second belt 120.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to telescoping devices. [Background technology]

[0002] Patent Document 1 discloses a technique for forming an expandable pipe structure by spirally winding a first belt and a second belt disposed inside the first belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4607772 Summary of the Invention [Problem to be solved by the invention]

[0004] Since the first belt is disposed outside the second belt, the spiral radius of the first belt forming the pipe structure is larger than the spiral radius of the second belt forming the pipe structure. Since the lengths of the first belt and the second belt forming the pipe structure of a predetermined length are different from each other, there is a problem that stress occurs in at least one of the first belt and the second belt.

[0005] The present disclosure has been made in consideration of such problems, and provides an expansion device that reduces the stress generated in two belts that are spirally wound together to form a pipe structure. [Means for solving the problem]

[0006] The telescopic device according to one aspect of the present disclosure includes: an expandable pipe structure formed by spirally winding a first belt and a second belt disposed inside the first belt around an axis; a first belt case in which a portion of the first belt that does not form the pipe structure is stored in a spiral shape; a second belt case in which a portion of the second belt that does not form the pipe structure is stored in a spiral shape; Equipped with The first belt case and the second belt case are integrally formed, The thickness of the first belt is thinner than the thickness of the second belt. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to realize an expansion device that reduces stress generated in two belts that are spirally wound to form a pipe structure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is an explanatory diagram showing the configuration of an extension device of a reference example. [Figure 2] FIG. 10 is an explanatory diagram showing the configuration of an extension device of a reference example. [Figure 3] FIG. 10 is an explanatory diagram showing a cross section of a pipe structure of a reference example. [Figure 4] FIG. 1 is an explanatory diagram showing the configuration of an extension device according to a first embodiment. [Figure 5] FIG. 2 is an explanatory diagram showing the configuration of a belt case according to the first embodiment. [Figure 6] FIG. 2 is an explanatory diagram showing the configuration of a first belt and a second belt according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Reference example> An extension device 60 of a reference example will be described with reference to Figures 1 to 3. Figure 1 is an explanatory diagram showing the configuration of an extension device 60 having a pipe structure.

[0010] The telescopic device 60 of this reference example has a pipe structure 100, a first belt case 10, a second belt case 20, a guide unit 30, a drive unit 40, and a mounting unit 50. The pipe structure 100 is formed by winding a first belt 110 and a second belt 120 in a spiral shape. The first belt case 10 stores the portion of the first belt 110 that does not form the pipe structure 100 in a spiral shape. The second belt case 20 stores the portion of the second belt 120 that does not form the pipe structure 100 in a spiral shape. The guide unit 30 guides the first belt 110 and the second belt 120 and winds them in a spiral shape. The drive unit 40 rotates the guide member 32 of the guide unit 30. The mounting unit 50 is attached to the tip of the pipe structure 100.

[0011] When the guide member 32 is driven by the drive unit 40 to rotate in one direction, the first belt 110 and the second belt 120 are guided by the guide member 32 and wound spirally, causing the pipe structure 100 to extend upward in FIG. 1 . When the guide member 32 rotates in the opposite direction, the first belt 110 and the second belt 120 are released and housed in the first belt case 10 and the second belt case 20, respectively, causing the pipe structure 100 to shorten. Instead of rotating the guide member 32, the pipe structure 100 itself may be rotated to expand or contract. The first belt 110 and the second belt 120 may be made of metal (e.g., a springy metal such as spring stainless steel). The first belt 110 and the second belt 120 may also be made of other materials, such as a deformable resin.

[0012] Fig. 2 is an explanatory diagram showing how the pipe structure 100 is formed by winding the first belt 110 and the second belt 120. In Fig. 2, for convenience of illustration, the outline of the second belt 120 is drawn with a dashed line. The upper left of Fig. 2 shows the state before winding, and the upper right shows a planar development of how the first belt 110 and the second belt 120 overlap when wound.

[0013] The pipe structure 100 is formed by spirally winding a first belt 110 and a second belt 120 disposed inside the first belt 110 around an axis CX. The first belt 110 has a first flat portion 111 and a plurality of first engagement portions 112 arranged in a plurality of rows along the longitudinal direction of the first belt 110. The first flat portion 111 is a flat, band-shaped portion without any protrusions or recesses. The first engagement portions 112 are arranged in two rows at regular intervals along the longitudinal direction of the first belt 110. The second belt 120 has a second flat portion 121 and a plurality of second engagement portions 122 arranged in a plurality of rows along the longitudinal direction of the second belt 120. The second flat portion 121 is a flat, band-shaped portion without any protrusions or recesses. The second engagement portions 122 are arranged in two rows at regular intervals along the longitudinal direction of the second belt 120.

[0014] In the pipe structure 100 shown in the lower part of Fig. 2, the first belt 110 is wound at a constant pitch Pt along the axis CX. The distance Le between the two rows of first engagement portions 112 along the axis CX is equal to 1 / 2 of the winding pitch Pt. The second belt 120 has the same configuration.

[0015] The first belt 110 has a width W1, and the second belt 120 has a width W2. These widths W1 and W2 are substantially equal and set to a value slightly smaller than the winding pitch Pt.

[0016] The first belt 110 and the second belt 120 are overlapped and spirally wound while being shifted from each other by half the winding pitch Pt. As a result, the two rows of first engagement portions 112 of the first belt 110 engage with the second engagement portions of the two second belts 120 that are overlapped inside the first belt 110.

[0017] 1, the first belt case 10 is supported in a state where it can rotate around the axis line CX. The first belt case 10 rotates according to the length of the first belt 110 pulled out from the first belt case 10. Similarly, the second belt case 20 is supported in a state where it can rotate around the axis line CX. The second belt case 20 rotates according to the length of the second belt 120 pulled out from the second belt case 20.

[0018] The telescopic device 60 may transport luggage placed on the loading section 50.

[0019] 3 is a cross-sectional view of a pipe structure 100 according to a reference example. The first engagement portion 112 of the first belt 110 is configured as a first hollow protrusion 114 (hollow truncated cone-shaped protrusion) that protrudes toward the axis CX. The first engagement portion 112 has an opening 116 in the center. The opening 116 may be omitted. That is, the tip of the first hollow protrusion 114 may be closed.

[0020] The second engagement portion 122 of the second belt 120 is configured to mate with the first engagement portion 112 of the first belt 110. In the reference example, the second engagement portion 122, like the first engagement portion 112, is configured as a second hollow protrusion 124 (hollow truncated cone-shaped protrusion) that protrudes toward the axis line CX and has an opening 126 at its center. Note that the opening 126 may be omitted. In other words, the tip of the second hollow protrusion 124 may be closed. The second engagement portion 122 may be configured to have substantially the same shape as the first engagement portion 112, and it is preferable that the shape of the protrusion be slightly larger than that of the first engagement portion 112.

[0021] The inner surface of the first hollow protrusion 114 and the outer surface of the second hollow protrusion 124 are configured to be in surface contact with each other. This configuration can reduce contact pressure compared to when the two engaging portions are in point contact. As a result, deformation due to contact can be reduced, and noise and vibration can also be reduced.

[0022] The angle θ formed between the first hollow protrusion 114 and the first flat portion 111 is preferably set in the range of 30 degrees to 85 degrees. The same is true for the second hollow protrusion .

[0023] The first engagement portion 112 protrudes inward (toward the axis CX) from the inner surface 111i of the first flat portion 111. On the other hand, there is no portion that protrudes outward from the outer surface 111o of the first flat portion 111. The second belt 120 has the same configuration.

[0024] The protrusion height of the first hollow protrusion portion 114 and the protrusion height of the second hollow protrusion portion 124 are equal to each other. Therefore, the thickness of the first belt 110 and the thickness of the second belt 120 are equal to each other.

[0025] <Embodiment 1> First, we will explain the problem that the inventors found with the telescopic device 60 of the above-mentioned reference example. Because the first belt 110 is disposed outside the second belt 120 in the pipe structure 100, the spiral radius of the first belt 110 forming the pipe structure 100 is larger than the spiral radius of the second belt forming the pipe structure 100. Because the first belt 110 forming the pipe structure 100 is longer than the second belt 120, the amount of rotation of the first belt case 10 is larger than the amount of rotation of the second belt case 20. Therefore, when the first belt case 10 and the second belt case 20 are integrated, there was a problem that the tensile stress generated in the first belt 110 was large and the compressive stress generated in the second belt 120 was large. Therefore, the first embodiment realizes a telescopic device that reduces the stress generated in the first belt 110 and the second belt 120.

[0026] The following describes the extension device according to the first embodiment, focusing on the differences from the extension device according to the comparative example. The same components are given the same reference numerals, and the description will be omitted as appropriate.

[0027] 4 is an explanatory diagram showing the configuration of the extension device 200 according to the embodiment 1. The extension device 200 includes a belt case 80 in which the first belt case 10 and the second belt case 20 are integrally formed.

[0028] FIG. 5 is an explanatory diagram showing a cross section of the belt case 80. The belt case 80 includes a housing 81 that forms a cylindrical body with a top and a bottom, and a partition 82 that divides the space inside the housing 81 into two sections, upper and lower. The housing 81 and the partition 82 are provided with through holes through which the guide member 32 passes. The belt case 80 is supported in a rotatable state relative to the guide member 32. The upper section of the belt case 80 corresponds to the first belt case 10, and the lower section corresponds to the second belt case 20. The diameter of the first belt case 10 and the diameter of the second belt case 20 may be equal to each other. One end of the first belt 110 and one end of the second belt 120 may be fixed to the inner surface of the housing 81.

[0029] 6 is an explanatory diagram showing the configurations of the first belt 110 and the second belt 120 according to the first embodiment. The thickness T1 of the first belt 110 is thinner than the thickness T2 of the second belt 120. For example, the protrusion height of the first hollow protrusion portion 114 may be smaller than the protrusion height of the second hollow protrusion portion 124. Alternatively, the thickness of the first flat portion 111 may be thinner than the thickness of the second flat portion 121.

[0030] Because the thickness T1 is thinner than the thickness T2, when the belt case 80 is viewed from above, the spiral shape formed by the first belt 110 (referred to as the first spiral shape) is disposed outside the spiral shape formed by the second belt 120 (referred to as the second spiral shape). In other words, when the first spiral shape is approximated by a plurality of first concentric circles and the second spiral shape is approximated by a plurality of second concentric circles, the radius of each first concentric circle is larger than the radius of the corresponding second concentric circle.

[0031] In this case, the length of the first belt 110 pulled out when the first belt case 10 makes one revolution increases. In other words, the amount of rotation of the first belt case 10 decreases compared to when the first belt case 10 and the second belt case 20 are configured as separate bodies. As a result, when the first belt case 10 and the second belt case 20 are configured as an integrated body, the tensile stress generated in the first belt 110 and the compressive stress generated in the second belt 120 decrease.

[0032] Furthermore, since the first belt case 10 and the second belt case 20 are integrated, the belt case can be made smaller. Also, since the number of parts is reduced, costs are reduced.

[0033] Next, the inventors' findings will be explained using mathematical formulas. When the length of the pipe structure 100 is a predetermined length h, the lengths of the first belt 110 and the second belt 120 that form the pipe structure 100 are expressed by formulas (1) and (2), respectively. Specifically, the predetermined length h is the length when the pipe structure 100 is stretched to its maximum.

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[0034] Meanwhile, the first belt 110 and the second belt 120 are housed in a spiral shape in the belt case 80. The length of each belt housed in the belt case 80 is expressed by the formula (3).

number

[0035] If the interval between turns is t, the number of turns n is n=(R o -R i ) / t, and r j =R i +j*t. Note that t for the first belt 110 is also referred to as t1, and t for the second belt 120 is also referred to as t2. Transforming equation (3) yields equation (4).

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[0036]

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[0037]

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[0038] When the first belt case 10 and the second belt case 20 are configured as separate bodies and formulas (5) to (7) are satisfied, the amount of rotation of the first belt case 10 and the amount of rotation of the second belt case 20 while the length of the pipe structure 100 is extended from the minimum value to the maximum value will be the same. Therefore, when the first belt case 10 and the second belt case 20 are integrated, the tensile stress generated in the first belt 110 and the compressive stress generated in the second belt 120 will be reduced.

[0039] Ideally, when the first belt case 10 and the second belt case 20 are configured as separate bodies, the amount of rotation of the first belt case 10 and the amount of rotation of the second belt case 20 until the pipe structure 100 is extended to a desired length should match. However, when the thicknesses of the first belt 110 and the second belt 120 are constant, it is difficult to perfectly match the number of rotations of the first belt case and the second belt case 20. Therefore, the thickness of the first belt 110 may be changed in the extension direction of the first belt 110, or the thickness of the second belt 120 may be changed in the extension direction of the second belt 120, so that the amount of rotation of the first belt case 10 and the amount of rotation of the second belt case 20 until the pipe structure 100 is extended to a desired length match.

[0040] In the stretching device according to the first embodiment, the thickness of the first belt 110 is made thinner than the thickness of the second belt 120, so that the stress generated in the first belt 110 and the second belt 120 can be reduced.

[0041] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0042] 10 First Belt Case 20 Second Belt Case 30 Guide section 32 Guide member 40 Drive unit 50 Placement section 60, 200 telescopic device 70 Control Unit 80 Belt Case 81 Case 82 Partition 100 Pipe Structure 110 First Belt 111 1st flat part 112 first engagement portion 114 First hollow protrusion 116, 126 opening 120 Second Belt 121 2nd flat part 122 second engagement portion 124 Second hollow protrusion

Claims

1. an expandable pipe structure formed by spirally winding a first belt and a second belt disposed inside the first belt around an axis; a first belt case that stores a portion of the first belt that does not form the pipe structure in a spiral shape; a second belt case that stores a portion of the second belt that does not form the pipe structure in a spiral shape; Equipped with the first belt case and the second belt case are integrally formed, The thickness of the first belt is thinner than the thickness of the second belt, the first belt and the second belt have first hollow protrusions and second hollow protrusions that engage with each other, The protrusion height of the first hollow protrusion portion is lower than the protrusion height of the second hollow protrusion portion. Telescopic device.

2. The diameter of the first belt case and the diameter of the second belt case are equal to each other. The telescopic device according to claim 1 .

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