Helical retractable mechanism and tubular expandable body strip

Abstract

To provide a spiral advance / retreat operation device capable of realizing both rigidity of a cylindrical expansion body and winding performance of band materials (first band material and second band material), and a band material for a cylindrical expansion body.SOLUTION: A spiral advance / retreat operation device forms a cylindrical expansion body 100 by spirally overlapping and winding a first band material 110 and a second band material 120 around a common axis CX while they are offset from each other in the axial direction. The first band material comprises a first engagement protrusion row L1 and a second engagement protrusion row L2 formed of a plurality of engagement protrusions. The second band material has a first engagement portion row L3 and a second engagement portion row L4 formed of a plurality of engagement portions. An inclination angle of the engagement protrusions in a cross section on a plane including the axial direction is set to be larger than an inclination angle of the engagement protrusions in a cross section on a plane including a circumferential direction of the cylindrical expansion body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This disclosure relates to a helical reciprocating mechanism and a strip material for a cylindrical expandable body. [Background technology]

[0002] Patent Document 1 discloses a spiral retractable mechanism that forms a cylindrical expandable body by spirally overlapping and winding a first strip material and a second strip material placed inside the first strip material, with the strip material offset from each other in the axial direction around a common axis (offset by half a width).

[0003] The first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions, which are arranged in its longitudinal direction and consist of multiple engaging protrusions that are convex toward the axis. The second strip material, on the other hand, comprises a first row of engaging parts and a second row of engaging parts, which are arranged in its longitudinal direction and consist of multiple engaging parts. The engaging parts are configured such that when the first strip material and the second strip material are spirally overlapped and wound together, the frustoconical engaging protrusions engage with each other in a detachable manner. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 4607772 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, from the viewpoint of achieving both rigidity (vertical load-bearing capacity) of the tubular expandable body and windability (ease of winding) of the strip material (first and second strip material), there is room for improvement in the frustoconical engaging projection described in Patent Document 1. This disclosure was made to solve these problems and provides a spiral reciprocating mechanism and a strip material for a tubular expandable body that can achieve both rigidity (vertical load-bearing capacity) of the tubular expandable body and windability (ease of winding) of the strip material (first and second strip material). [Means for solving the problem]

[0006] The helical retractable mechanism according to this disclosure is a helical retractable mechanism that constitutes a cylindrical expandable body by spirally overlapping and winding a first strip material and a second strip material disposed inside the first strip material around a common axis, with the strip material offset from the first strip material in the axial direction, wherein the first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions arranged in its longitudinal direction and composed of a plurality of engaging protrusions convex toward the axis, and the second strip material comprises a first row of engaging parts and a second row of engaging parts composed of a plurality of engaging parts arranged in its longitudinal direction, wherein the engaging parts are configured to engage with the engaging protrusions in a detachable manner when the first strip material and the second strip material are spirally overlapped and wound around each other, and the inclination angle of the engaging protrusions in a cross-section in a plane including the axial direction is set to be greater than the inclination angle of the engaging protrusions in a cross-section in a plane including the circumferential direction of the cylindrical expandable body.

[0007] This configuration makes it possible to achieve both rigidity (load-bearing capacity in the vertical direction) and ease of wrapping (ease of wrapping) of the tubular expandable body and the strip material (first strip material and second strip material). This is achieved by making the inclination angle of the engaging projection in a cross-section with a plane including the vertical direction greater than the inclination angle of the engaging projection in a cross-section with a plane including the circumferential direction of the tubular expandable body.

[0008] Furthermore, in the spiral reciprocating mechanism described above, the engaging projection may be an elliptical frustoconical projection, provided on the first strip material such that its major axis coincides with the longitudinal direction of the first strip material.

[0009] Furthermore, in the spiral reciprocating mechanism described above, the engaging projection may be an elliptical frustoconical projection, and may be provided on the first strip material with its major axis inclined at a predetermined angle with respect to the longitudinal direction of the first strip material.

[0010] The strip for a cylindrical telescopic body according to the present disclosure is a strip used as the first strip of a spiral advancing and retreating actuator that forms a cylindrical telescopic body by spirally winding a first strip and a second strip disposed inside the first strip around a common axis in a state where they are displaced from each other in the axial direction. The first strip includes a first engaging projection row and a second engaging projection row that are disposed in the longitudinal direction thereof and are composed of a plurality of engaging projections that protrude toward the axis. The inclination angle of the engaging projection in a cross section by a plane including the axial direction is set to be larger than the inclination angle of the engaging projection in a cross section by a plane including the circumferential direction of the cylindrical telescopic body.

[0011] Moreover, another strip for a cylindrical telescopic body according to the present disclosure is a strip used as the second strip of a spiral advancing and retreating actuator that forms a cylindrical telescopic body by spirally winding a first strip and a second strip disposed inside the first strip around a common axis in a state where they are displaced from each other in the axial direction. The first strip includes a first engaging projection row and a second engaging projection row that are disposed in the longitudinal direction thereof and are composed of a plurality of engaging projections that protrude toward the axis. The second strip includes a first engaging portion row and a second engaging portion row that are composed of a plurality of engaging portions disposed in the longitudinal direction thereof. The engaging portion is configured such that the engaging projection can be engaged and disengaged with the first strip and the second strip in a state where they are spirally wound around each other. The inclination angle of the engaging projection in a cross section by a plane including the axial direction is set to be larger than the inclination angle of the engaging projection in a cross section by a plane including the circumferential direction of the cylindrical telescopic body.

Advantages of the Invention

[0012] [[ID=IM11]]According to the present disclosure, it is possible to provide a spiral advancing and retreating actuator that can achieve both the rigidity of the cylindrical telescopic body (load-bearing capacity in the vertical direction) and the winding property (ease of winding) of the strips (the first strip and the second strip), and a strip for a cylindrical telescopic body.

Brief Description of the Drawings

[0013] [Figure 1] An explanatory diagram showing the configuration of a telescopic device including a spiral-wound telescopic shaft. [Figure 2] An explanatory diagram showing how a spiral-wound telescopic shaft is formed. [Figure 3] (a) Cross-sectional view of the spiral winding type telescopic shaft in the reference example, (b) Cross-sectional view of the spiral winding type telescopic shaft in the comparative example, (c) Diagram showing a modified example of the second engaging portion 122, (d) Diagram showing a modified example of the second engaging portion 122. [Figure 4] This diagram illustrates the forces acting on the engaging pin 14 when an external force is applied to the spiral-wound telescopic shaft 100A. [Figure 5] (a) A plan view of the first strip-shaped member 110 provided with the engagement pin 14A of the embodiment; (b) A cross-sectional view of the engagement pin 14A in a plane including the vertical direction (axis CX direction); (c) A cross-sectional view of the engagement pin 14A in a plane including the circumferential direction. [Figure 6] An explanatory diagram of a modified example of the engaging projection (e.g., engaging pin 14A). [Modes for carrying out the invention]

[0014] <Reference example> A reference example of an extension / retraction device 60 (spiral-shaped reciprocating device) will be described with reference to Figures 1 to 3.

[0015] Figure 1 is an explanatory diagram showing the configuration of an extendable device 60 equipped with a spiral-wound extendable shaft. The extendable device 60 in this reference example has a spiral-wound extendable shaft 100 formed by spirally winding two strip-shaped members 110 and 120, a first housing section 10 for housing the first strip-shaped member 110, a second housing section 20 for housing the second strip-shaped member 120, a guide section 30 that guides the two strip-shaped members 110 and 120 and winds them spirally, a drive section 40 that rotates the guide member 32 of the guide section 30, and a cap section 50 attached to the tip of the spiral-wound extendable shaft 100. When the drive section 40 drives the guide member 32 to rotate in one direction, the two strip-shaped members 110 and 120 are guided by the guide member 32 and wound spirally, and the spiral-wound extendable shaft 100 extends upward in Figure 1. When the guide member 32 rotates in the opposite direction, the winding of the two strip-shaped members 110 and 120 is released, and they are housed in their respective storage sections 10 and 20, shortening the spiral-wound telescopic shaft 100. Alternatively, instead of rotating the guide member 32, the spiral-wound telescopic shaft 100 itself may be rotated to perform the extension and retraction. The strip-shaped members 110 and 120 can be made of metal (for example, a springy metal such as stainless steel for springs). The strip-shaped members 110 and 120 may also be made of other materials such as deformable resin.

[0016] Figure 2 is an explanatory diagram showing how a spiral-wound telescopic shaft 100 is formed by winding two strip-shaped members 110 and 120 together. In Figure 2, for ease of illustration, the outer shape of the second strip-shaped member 120 is drawn with a dashed line. The upper left of Figure 2 shows the state before winding, and the upper right shows the overlapping arrangement of the two strip-shaped members 110 and 120 in the wound state, unfolded on a plane.

[0017] The spiral-wound telescopic shaft 100 is formed by spirally winding a first strip-shaped member 110 and a second strip-shaped member 120, which is positioned inside the first strip-shaped member 110, around an axis CX. The first strip-shaped member 110 has a first flat strip portion 111 and a plurality of first engaging portions 112 arranged in multiple rows along the longitudinal direction of the first strip-shaped member 110. The first flat strip portion 111 is a flat, strip-shaped portion without protrusions or recesses. The first engaging portions 112 are arranged in two rows at regular intervals along the longitudinal direction of the first strip-shaped member 110. The second strip-shaped member 120 has a second flat strip portion 121 and a plurality of second engaging portions 122 arranged in multiple rows along the longitudinal direction of the second strip-shaped member 120. The second flat strip portion 121 is a flat, strip-shaped portion without protrusions or recesses. The second engaging portion 122 is arranged in two rows at regular intervals along the longitudinal direction of the second strip-shaped member 120.

[0018] In the spiral-wound telescopic shaft 100 shown in the lower part of Figure 2, the first strip-shaped member 110 is wound at a constant pitch Pt along the axis CX. The distance Le between the two rows of first engaging portions 112 along the direction of axis CX is equal to half the winding pitch Pt. The second strip-shaped member 120 has a similar configuration.

[0019] The first strip-shaped member 110 has a width W1, and the second strip-shaped member 120 has a width W2. These widths W1 and W2 are approximately equal and set to a value slightly smaller than the winding pitch Pt. The two strip-shaped members 110 and 120 are overlapped and wound spirally, offset from each other by half the winding pitch Pt. As a result, the two rows of first engaging portions 112 of the first strip-shaped member 110 engage with the second engaging portions 122 of the two second strip-shaped members 120 that are overlapped inside the first strip-shaped member 110.

[0020] Figure 3(a) is a cross-sectional view of the spiral winding type telescopic shaft 100 in a reference example. The first engaging portion 112 of the first strip-shaped member 110 is configured as a first hollow projection 114 (hollow frustoconical projection) that protrudes toward the axis CX. The first engaging portion 112 also has an opening 116 in the center. The opening 116 may be omitted. That is, the tip of the first hollow projection 114 may be closed.

[0021] The second engaging portion 122 of the second strip-shaped member 120 is configured to engage with the first engaging portion 112 of the first strip-shaped member 110. In the reference example, the second engaging portion 122 is also configured as a second hollow projection 124 (hollow frustoconical projection) protruding toward the axis CX, similar to the first engaging portion 112, and has an opening 126 in its center. The opening 126 may be omitted. That is, the tip of the second hollow projection 124 may be closed. The second engaging portion 122 may be configured to have substantially the same shape as the first engaging portion 112, and it is preferable that the shape of the protrusion be slightly larger than that of the first engaging portion 112.

[0022] The inner surface of the first hollow projection 114 and the outer surface of the second hollow projection 124 are configured to be in surface contact with each other. In this configuration, the contact pressure can be reduced compared to when the two engaging parts are in point contact. As a result, deformation due to contact can be reduced, and noise and vibration can also be reduced.

[0023] The angle θ between the first hollow projection 114 and the first flat band 111 is preferably set in the range of 30 to 85 degrees. The same applies to the second hollow projection 124.

[0024] The first engaging portion 112 protrudes inward (towards the axis CX) from the inner surface 111i of the first flat strip portion 111. On the other hand, there is no portion that protrudes outward from the outer surface 111o of the first flat strip portion 111. These configurations are the same for the second strip-shaped member 120.

[0025] Figure 3(b) is a cross-sectional view of a spiral-wound telescopic shaft in a comparative example. In this comparative example, the first strip-shaped member 11 has a first flat strip portion 12 and a solid engaging pin 14. The engaging pin 14 is joined to the first flat strip portion 12 by welding, and a weld mark 16 is formed that protrudes to the outside of the first flat strip portion 12. The second strip-shaped member 21 has a second flat strip portion 22 and an engaging hole 24.

[0026] In this comparative example, the spiral-wound telescopic shaft requires numerous engagement pins 14 to be joined to the first flat strip portion 12, which increases the weight and cost of the first strip-shaped member 11.

[0027] On the other hand, in the spiral winding type telescopic shaft 100 of the reference example shown in Figure 3(a), the first engaging portion 112 of the first strip-shaped member 110 is configured as a hollow projection, so a lighter and lower-cost spiral winding type telescopic shaft can be provided compared to using a solid engaging pin.

[0028] The first hollow projection 114 can be formed, for example, by press molding the first strip-shaped member 110 before the first hollow projection 114 is formed. The same applies to the second hollow projection 124.

[0029] As described above, in the above-mentioned reference example, the first engaging portion 112 of the first strip-shaped member 110 is configured as the first hollow projection 114, so a lightweight and low-cost telescopic shaft can be provided compared to using a solid engaging pin. Furthermore, since the first hollow projection 114 and the second hollow projection 124 are configured to make surface contact, the contact pressure can be reduced compared to when the two engaging portions make point contact. As a result, deformation due to contact can be reduced, and noise and vibration can also be reduced.

[0030] Figures 3(c) and 3(d) show modified examples of the second engaging portion 122. As shown in Figure 3(c), instead of the second hollow projection 124, an engaging hole (through hole) formed in the second strip-shaped member 120 may be used as the second engaging portion 122. In this case, as shown in Figure 3(d), the peripheral portion 122a of the second engaging portion 122 (engaging hole) may be chamfered, or instead of chamfering, it may be given a rounded edge.

[0031] <Embodiment> First, we will explain the problems that the inventors have identified with the telescopic device 60 (helical reciprocating device) of the above reference example.

[0032] As described above, in the above reference example, the telescopic device 60 (helical reciprocating operating device) is configured as a helical-wound telescopic shaft 100 (an example of a cylindrical telescopic body in this disclosure) by spirally overlapping and winding a first strip-shaped member 110 (an example of a first strip material in this disclosure) and a second strip-shaped member 120 (an example of a second strip material in this disclosure) which is arranged inside the first strip-shaped member 110, with the strips offset from each other in the direction of the axis CX around a common axis CX (offset by half a width).

[0033] For example, the first strip-shaped member 110 of the above reference example includes a first row of engaging protrusions L1 and a second row of engaging protrusions L2 (see Figure 2), which are composed of a plurality of first hollow protrusions 114 (see Figure 3(a); an example of an engaging protrusion of the present disclosure; hereinafter also referred to as engaging protrusion 114) arranged in its longitudinal direction and convex toward the axis CX.

[0034] On the other hand, the second strip-shaped member 120 of the above reference example includes a first row of engagement portions L3 and a second row of engagement portions L4 (see Figure 2), which are composed of a plurality of second engagement portions 122 (an example of an engagement portion in this disclosure) arranged in the longitudinal direction thereof.

[0035] The second engaging portion 122 is configured such that the engaging projection 114 can engage with the first strip-shaped member 110 and the second strip-shaped member 120 in a spiral manner when they are wrapped around each other.

[0036] When using the spiral wound type telescopic shaft 100 configured by spirally winding and overlapping the first strip member 110 and the second strip member 120 arranged inside the first strip member 110 in a state of being offset from each other in the axial direction CX around the common axis CX as described above, there are the following problems.

[0037] Hereinafter, this problem will be described using a comparative example.

[0038] The comparative example is the spiral wound type telescopic shaft (cylindrical telescopic body) described in the above Patent Document 1. Hereinafter, it will be referred to as the spiral wound type telescopic shaft 100A. In the spiral wound type telescopic shaft 100A of the comparative example, a frustoconical engaging pin 14 (see FIG. 3(b)) as an engaging protrusion and an engaging hole 24 (see FIG. 3(b)) with which the engaging pin 14 can be engaged and disengaged are used.

[0039] FIG. 4 is a diagram showing the force acting on the engaging pin 14 when an external force is applied to the spiral wound type telescopic shaft 100A. In FIG. 4, the symbol F represents the force acting on the engaging pin 14 when an external force is applied to the spiral wound type telescopic shaft 100A. When an external force is applied to the spiral wound type telescopic shaft 100A, for example, when a heavy object is placed at a position shifted horizontally from the upper part and the central axis of the spiral wound type telescopic shaft 100A, an eccentric load acts on the spiral wound type telescopic shaft 100A. The angle θ 14 represents the pin angle (tilt angle) of the engaging pin 14. The pin angle (tilt angle) is the angle formed by the bottom surface and the side surface (outer peripheral surface) of the engaging pin 14. Hereinafter, the tilt angle θ 14 will also be referred to. F×cosθ 14 represents the force tending to disengage the engagement between the engaging pin 14 and the engaging hole 24. F×cosθ 14 is larger as the tilt angle θ 14 is smaller. μ×F×sinθ 14 represents the resistance force (frictional force) determined by the tilt angle θ 14 of the engaging pin 14 and the coefficient of friction μ.

[0040] In FIG. 4, F×cosθ 14 >μ×F×sinθ 14When this relationship occurs, slippage occurs between the engagement pin 14 and the engagement hole 24. In this case, the inclination angle θ 14 If the angle of inclination θ is small, even a small external force applied to the spiral-wound telescopic shaft 100A will cause the engagement between the engagement pin 14 and the engagement hole 24 to disengage. 14 If the value is small, the rigidity of the spiral-wound telescopic shaft 100A will decrease.

[0041] Here the inclination angle θ 14 If you increase it (for example, the tilt angle θ) 14 When the angle of inclination θ is 90°, the resistance to disengaging the engagement between the engagement pin 14 and the engagement hole 24 when an external force is applied increases (i.e., the vertical load-bearing capacity is improved). The vertical direction refers to the axial direction CX of the spiral winding type telescopic shaft 100A. 14 If you increase it (for example, the tilt angle θ) 14 When the first strip member 110 and the second strip member 120 are overlapped and wound spirally as described above (=90°), the tip of the engagement pin 14 is likely to interfere with the engagement hole 24 (around the engagement hole 24). As a result, it becomes difficult to correctly overlap and wind the first strip member 110 and the second strip member 120 spirally (i.e., the winding performance in the circumferential direction decreases). The circumferential direction refers to the direction around the spiral winding type telescopic shaft 100A.

[0042] As described above, when a frustoconical engaging projection (for example, an engaging pin 14) is used as the engaging projection, there is a trade-off between vertical load-bearing capacity and circumferential winding ability, making it difficult to achieve both simultaneously.

[0043] Next, as an embodiment, an example configuration for solving the above problems will be described.

[0044] This configuration example can also be applied to the spiral-wound telescopic shaft 100 using the engagement pin 14 of the comparative example (see Figure 3(b)), the spiral-wound telescopic shaft 100 using the first hollow projection 114 (hollow frustoconical projection; see Figure 3(a)) of the reference example, and spiral-wound telescopic shafts 100 using other engagement projections. Below, we will describe an example in which this configuration example is applied to the spiral-wound telescopic shaft 100 using the engagement pin 14 of the comparative example.

[0045] Figure 5(a) is a plan view of the first strip-shaped member 110 provided with the engagement pin 14A of the embodiment, Figure 5(b) is a cross-sectional view of the engagement pin 14A in a plane including the vertical direction (axis CX direction), and Figure 5(c) is a cross-sectional view of the engagement pin 14A in a plane including the circumferential direction.

[0046] As shown in Figure 5(a), the engagement pin of this embodiment (hereinafter referred to as engagement pin 14A) is not a frustoconical shape, but an elliptical frustoconical engagement projection with different inclination angles in the vertical direction (axis CX direction) and the circumferential direction. Specifically, the inclination angle θ of the engagement pin 14A in a cross-section with a plane including the vertical direction. 14A1 (See Figure 5(b)) shows the inclination angle θ of the engagement pin 14A in a cross-section with a plane including the circumferential direction. 14A2 (See Figure 5(c)) is greater than the tilt angle θ. 14A1 It is desirable to set the angle to 70-90°, taking into consideration the vertical load-bearing capacity. On the other hand, the inclination angle θ 14A2 This takes into account the ability to wrap around in the circumferential direction, and the inclination angle θ 14A1 It is preferable to use a smaller angle (generally 70° or less) (however, this will vary depending on the diameter of the spiral-wound telescopic shaft 100 and the height of the engagement pin 14A).

[0047] The engaging pin 14A has its upper surface oriented toward the axis CX, and its long axis AX 14A (See Figure 5(a)) is provided on the first strip-shaped member 110 in a state that coincides with the longitudinal direction of the first strip-shaped member 110. In this way, the inclination angle θ in the winding direction 14 This is the gentlest point, improving the ease of wrapping.

[0048] On the other hand, although not shown in the figures, the engagement hole (hereinafter referred to as engagement hole 24A) into which the engagement pin 14A engages is not circular in shape, but is an elliptical engagement hole (through hole) corresponding to the engagement pin 14A. The engagement hole 24A is provided in the second strip-shaped member 120 such that its major axis coincides with the longitudinal direction of the second strip-shaped member 120.

[0049] According to the above configuration of the engagement pin 14A, the inclination angle θ of the engagement pin 14A in a cross-section with a plane including the vertical direction is as follows: 14A1 (See Figure 5(b)) The inclination angle θ of the engagement pin 14A in a cross-section with a plane including the circumferential direction. 14A2 (See Figure 5(c)) This can be made larger. This improves the rigidity (vertical load-bearing capacity) of the spiral winding type telescopic shaft 100. Conversely, with the engagement pin 14A of the above configuration, the inclination angle θ of the engagement pin 14A in a cross-section with a plane including the circumferential direction. 14A2 (See Figure 5(c)) The inclination angle θ of the engagement pin 14A in a cross-section with a plane including the vertical direction. 14A1 (See Figure 5(b)) This allows for a smaller size. This improves the wrapability (ease of wrapping) of the strip-shaped member (especially the first strip-shaped member 110).

[0050] As described above, the oval-frustoconical engaging projection (for example, the engaging pin 14A) makes it possible to achieve both the rigidity (vertical load-bearing capacity) of the spiral winding telescopic shaft 100 and the winding ability (ease of winding) of the strip-shaped member (especially the first strip-shaped member 110).

[0051] As described above, this embodiment makes it possible to achieve both the rigidity (vertical load-bearing capacity) of the spiral winding type telescopic shaft 100 and the winding ability (ease of winding) of the strip-shaped member (especially the first strip-shaped member 110). This is due to the inclination angle θ of the engaging projection (e.g., engaging pin 14A) in a cross-section with a plane including the vertical direction. 14A1 (See Figure 5(b)) The inclination angle θ of the engaging projection (e.g., engaging pin 14A) in a cross-section of the spiral winding telescopic shaft 100 in a plane including the circumferential direction. 14A2This is due to making it larger than (see Figure 5(c)). In other words, a steeper angle (larger inclination angle θ) is used for vertical forces. 14 ) causes the engagement hole 24 and the engagement projection (for example, the engagement pin 14A) to come into contact, resulting in a frictional force (μ × F × sinθ in Figure 4). 14 (Reference) can be increased, and as a result, the axial rigidity of the spiral winding type telescopic shaft 100 can be increased. On the other hand, in the circumferential direction, the inclination angle can be made shallower (inclination angle θ 14 By making it smaller, it can contribute to smoother wrapping.

[0052] Next, I will explain some variations.

[0053] Figures 6(a) to 6(d) are explanatory diagrams of modified examples of the engaging projection (for example, the engaging pin 14A).

[0054] In the above embodiment, the frustoelliptic engagement projection (for example, the engagement pin 14A) has its major axis AX 14A (See Figure 5(a)) An example has been described in which the first strip-shaped member 110 is provided with the first strip-shaped member 110 in a state where the long axis of the first strip-shaped member 110 coincides with the longitudinal direction of the first strip-shaped member 110, but it is not limited to this. For example, as shown in Figure 6(a), an elliptical frustoconical engaging projection (for example, an engaging pin 14A) is provided with its long axis AX 14A at a predetermined angle θ with respect to the longitudinal direction of the first strip-shaped member 110 R It may be provided on the first strip-shaped member 110 in an inclined state. This predetermined angle θ R This is, for example, the winding lead angle (see Figures 2 and 6(a)). In this way, the vertical inclination angle θ 14A1 Because this is the steepest point, the axial rigidity of the spiral-wound telescopic shaft 100 can be increased. Furthermore, the elliptical frustoconical engaging projection (for example, the engaging pin 14A) is positioned at a predetermined angle θ. R When installed in an inclined position, although not shown in the diagram, the engagement hole 24A also has its long axis at a predetermined angle θ with respect to the longitudinal direction of the second strip-shaped member 120. R It is provided on the second strip-shaped member 120 in an inclined state.

[0055] Furthermore, although the above embodiment described an example in which the engaging projection (e.g., engaging pin 14) is not frustoconical but elliptical frustoconical, the elliptical frustoconical shape does not have to be mathematically perfect. For example, as shown in Figures 6(b) and 6(c), the side surface (outer surface) of the engaging projection (e.g., engaging pin 14A) may not be a straight line, but an arc shape (burring shape) that bulges outward (or inward) relative to the side surface (outer surface) of the reference elliptical frustoconical shape. In Figures 6(b) and 6(c), the dotted line represents the side surface (outer surface) of the reference elliptical frustoconical shape.

[0056] Furthermore, the inclination angle θ of the engaging projection (e.g., engaging pin 14A) in a cross-section with a plane including the vertical direction. 14A1 Regarding this, as shown in Figure 6(d), the inclination angle θ of the engaging projection (for example, the engaging pin 14A) near the base end (root side) of the spiral winding type telescopic shaft 100 14A1 The angle of inclination θ of the engaging projection (e.g., engaging pin 14A) near the tip of the spiral winding telescopic shaft 100 is reduced. 14A1 It may be made to a certain extent. In this way, when an external force is applied to the spiral-wound telescopic shaft 100 and the tip of the spiral-wound telescopic shaft 100 is displaced relative to the base end, causing the spiral-wound telescopic shaft 100 to bend, the amount of bending can be reduced.

[0057] The numerical values ​​shown in the above embodiments are all examples, and it goes without saying that other appropriate numerical values ​​can be used.

[0058] The embodiments described above are merely illustrative in all respects. The invention is not to be construed as being limited by the descriptions of the embodiments above. The invention can be carried out in a variety of other ways without departing from its spirit or main features. [Explanation of symbols]

[0059] 10...First housing section, 11...First strip-shaped member, 12...First flat strip section, 14...Engaging pin, 16...Weld mark, 20...Second housing section, 21...Second strip-shaped member, 22...Second flat strip section, 24...Engaging hole, 30...Guide section, 32...Guide member, 40...Drive section, 50...Cap section, 60...Telescopic device (helical reciprocating device), 70...Die, 71...Punch, 72...Punch, 73...Punch, 100...Helical winding type telescopic shaft (Cylindrical expandable body), 110...First strip-shaped member (first strip material), 111...First flat strip portion, 111i...Inner surface, 111o...Outer surface, 112...First engaging portion, 114...First hollow projection (engaging projection), 116...Opening, 118...Hole, 120...Second strip-shaped member (second strip material), 121...Second flat strip portion, 122...Second engaging portion, 124...Second hollow projection portion, 126...Opening, 210...First strip-shaped member, 211...First flat strip portion , 212...First engaging portion, 214...First hollow projection, 216...Top, 310...First strip-shaped member, 311...First flat strip portion, 312...First engaging portion, 314...First hollow projection, 316...Top, 318...Notch, 400...Spiral winding telescopic shaft, 410...First strip-shaped member, 411...First flat strip portion, 412...First engaging portion, 414...First hollow projection, 416...Opening, 420...Second strip-shaped member, 421 ...Second flat strip portion, 422...Second engaging portion, 500...Spiral winding telescopic shaft, 510...First strip-shaped member, 511...First flat strip portion, 512...First engaging portion, 514...First hollow projection portion, 516...Opening, 520...Second strip-shaped member, 521...Second flat strip portion, 522...Second engaging portion, 524...Peripheral portion, CX...Axis, L1...First row of engaging projections, L2...Second row of engaging projections, L3...First row of engaging portions, L4...Second row of engaging portions

Claims

1. A spiral extension and retraction device is formed by spirally overlapping and winding a first strip and a second strip, which is positioned inside the first strip, around a common axis, with the strips offset from each other in the axial direction, thereby forming a cylindrical expandable body. The first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions, which are arranged in the longitudinal direction and consist of a plurality of engaging protrusions that are convex toward the axis, The second strip material comprises a first row of engaging portions and a second row of engaging portions, each consisting of a plurality of engaging portions arranged in its longitudinal direction. The engagement portion is configured such that the engagement projection can engage with the first strip material and the second strip material in a spiral manner when they are wrapped around each other. A spiral retractable device in which the inclination angle of the engaging projection in a cross-section of a plane including the axial direction is set to be greater than the inclination angle of the engaging projection in a cross-section of a plane including the circumferential direction of the cylindrical expandable body.

2. The spiral reciprocating device according to claim 1, wherein the engaging projection is an elliptical frustoconical projection, and is provided on the first strip material such that its major axis coincides with the longitudinal direction of the first strip material.

3. The spiral reciprocating device according to claim 1, wherein the engaging projection is an elliptical frustoconical projection, and is provided on the first strip material with its major axis inclined at a predetermined angle with respect to the longitudinal direction of the first strip material.

4. A strip material used as the first strip material of a spiral retractable device that forms a cylindrical expandable body by spirally overlapping and winding a first strip material and a second strip material placed inside the first strip material around a common axis, with each strip material offset from the others in the axial direction, The first strip material comprises a first row of engaging protrusions and a second row of engaging protrusions, which are arranged in the longitudinal direction and consist of a plurality of engaging protrusions that are convex toward the axis, A strip material for a cylindrical expandable body, wherein the inclination angle of the engaging projection in a cross-section of a plane including the axial direction is set to be greater than the inclination angle of the engaging projection in a cross-section of a plane including the circumferential direction of the cylindrical expandable body.

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