telescopic device

Abstract

To provide a telescopic device which inhibits twisting of a belt.SOLUTION: A telescopic device according to the disclosure includes: an expandable tubular structure 10; and an inner guide member 1 disposed inside the tubular structure 10. The tubular structure 10 includes: an outer belt 5; and an inner belt 2. The outer belt 5 and the inner belt 2 each have a plurality of first protrusions 2a and holes arranged in a row in a longitudinal direction. The inner guide member 1 has a first spiral groove 1b extending along the plurality of first protrusions 2a. The inner guide member 1 rotates in one direction and the outer belt 5 and the inner belt 2 are sent out, so that they are spirally wound while being engaged with each other and the tubular structure 10 extends. The first spiral groove 1b has: a body 1ba; and an end portion 1bb extending from the body 1ba toward a root side of the inner guide member 1. A distance between the end portion 1bb of the first spiral groove 1b and the body 1ba of the first spiral groove 1b is small.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This disclosure relates to a telescopic device.

Background Art

[0002] In Patent Document 1, a spiral reciprocating actuator includes a first belt material and a second belt material each configured in a belt shape. The first belt material and the second belt material transition from a separated state where they are housed in a spiral shape on a horizontal plane to a cylindrical configuration state where they are spirally wound to form a cylindrical structure. The cylindrical structure is formed by spirally winding these belt materials at positions shifted from each other in the axial direction around the axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have discovered the following problems. In such a spiral reciprocating actuator, when transitioning from the separated state to the cylindrical configuration state, the belt material (belt) may be twisted. The twisting of the belt material may cause excessive contact between the belt material and the spiral groove of the inner guide member.

[0005] This disclosure has been made in view of the above problems, and provides a telescopic device capable of suppressing the twisting of the belt.

Means for Solving the Problems

[0006] The telescopic device according to this disclosure is a telescopic device including a telescopic cylindrical structure and an inner guide member disposed inside the cylindrical structure, The cylindrical structure comprises an outer belt and an inner belt positioned inside the outer belt. The outer belt and the inner belt are provided with a plurality of first protrusions and holes arranged in a row in the longitudinal direction. The inner guide member has a first helical groove extending along the plurality of first protrusions, As the inner guide member rotates to one side, the outer belt and the inner belt are fed out and wound spirally while engaging with each other, causing the cylindrical structure to extend. As the inner guide member rotates to the other side, the outer belt and the inner belt are pulled in, causing them to unwind and the tubular structure to contract. The first helical groove comprises a main body and an end portion extending from the main body toward the root side of the inner guide member. The distance between the end of the first helical groove and the body of the first helical groove is small.

[0007] Furthermore, the spiral pitch at the end of the first spiral groove may be smaller than the spiral pitch of the body of the first spiral groove, or the width at the end of the first spiral groove may be wider than the width of the body of the first spiral groove.

[0008] The outer belt and the inner belt are provided with a plurality of second protrusions arranged in a single row in the longitudinal direction on the base side of the inner guide member, relative to the plurality of first protrusions. The inner guide member further comprises a second helical groove extending along the plurality of second protrusions, The second helical groove comprises a main body and an end portion extending from the main body toward the root side of the inner guide member. The device may be characterized by having a small distance between the end of the second helical groove and the body of the second helical groove. [Effects of the Invention]

[0009] According to this disclosure, it is possible to suppress the twisting of the belt. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall perspective view of the expandable device according to Embodiment 1. [Figure 2] This is a perspective view of the main part of the expandable device according to Embodiment 1. [Figure 3] This is a perspective view of the main part of the expandable device according to Embodiment 1. [Figure 4] This is a perspective view of an example of an inner guide member according to Embodiment 1. [Figure 5] These are cross-sectional and enlarged cross-sectional views of an example of an inner guide member at the cutting line VV. [Figure 6] This diagram shows the operation of the expandable device according to Embodiment 1. [Figure 7] This is a perspective view of another example of the inner guide member according to Embodiment 1. [Figure 8] This is a perspective view of the main part of an expandable / contractable device relating to the problems that the present invention aims to solve. [Modes for carrying out the invention]

[0011] It should be noted that the right-handed XYZ coordinate system shown in Figure 1 and other drawings is merely for convenience in explaining the positional relationships of the components. Typically, the positive Z-axis direction is vertically upward, and the XY plane is the horizontal plane, and this is consistent across drawings.

[0012] (Related technologies) Prior to describing specific embodiments applying this disclosure, an expandable / contractable device relating to the technology of this disclosure will be described with reference to Figure 8. The expandable / contractable device 900 shown in Figure 8 can extend or contract a cylindrical structure 90. For the sake of clarity, a portion of the inner belt 2, the cover, and the upper belt case have been omitted from the illustration in Figure 8.

[0013] The operation of the telescopic device 900 to extend the cylindrical structure 90 will be described. The inner guide member 91 rotates in one direction around the central axis C9. Then, the inner guide member 91 winds up the outer belt 95 and the inner belt 92. Subsequently, the outer belt 95 is sent out from an upper belt case (not shown) through a first opening of a cover (not shown) to the inner guide member 91, and the inner belt 92 is sent out from the lower belt case 93 through a second opening of the cover to the inner guide member 91. The outer belt 95 and the inner belt 92 are wound around the inner guide member 91 in a spiral while engaging with each other. In other words, the outer belt 95 and the inner belt 92 transition from a separated state stored in the upper belt case and the lower belt case 93, respectively, to a cylindrical configuration state in which the outer belt 95 and the inner belt 92 are wound in a spiral. Thereby, the cylindrical structure 90 extends.

[0014] Also, the operation of the telescopic device 900 to contract the cylindrical structure 90 will be described. The inner guide member 91 rotates in the other direction around the central axis C9. Then, the outer belt 95 and the inner belt 92 that have already engaged and been wound around each other unwind. Subsequently, the outer belt 95 is drawn from the inner guide member 91 through the first opening of the cover described above into the upper belt case described above, and the inner belt 92 is sent out from the inner guide member 91 through the second opening of the cover described above to the lower belt case 93. The outer belt 95 is stored in the upper belt case, and the inner belt 92 is stored in the lower belt case 93. In other words, the outer belt 95 and the inner belt 92 transition from a cylindrical configuration state in which they are wound in a spiral to a separated state stored in the upper belt case and the lower belt case 93, respectively. Thereby, the cylindrical structure 90 contracts.

[0015] In the extension operation or the contraction operation of such a telescopic device 900, the above-described separated state and the above-described cylindrical configuration state are transitioned. The inner belt 92 includes a contact portion 92f, a separation portion 92g, and a housed portion 92h. The contact portion 92f, the separation portion 92g, and the housed portion 92h are connected in this order in the longitudinal direction of the inner belt 92. The contact portion 92f is spirally wound around the outer belt 95 and contacts the inner guide member 91. The separation portion 92g extends from the end of the contact portion 92f to the lower belt case 93 and is separated from the inner guide member 91. The housed portion 92h extends from the end of the separation portion 92g and is housed in the lower belt case 93. The side wall 93b of the lower belt case 93 extends annularly around the central axis C9. The housed portion 92h of the inner belt 92 may be wound along the inner wall surface of the side wall 93b.

[0016] Further, the inner belt 92 includes a plurality of first protrusions 92a arranged in a row in the longitudinal direction of the inner belt 92, and a plurality of second protrusions (not shown) arranged in a row below the plurality of first protrusions 92a. The plurality of first protrusions 92a protrude toward the inner guide member 91 side and have a shape that can be fitted with the first spiral groove 91b. The plurality of first protrusions 92a in the contact portion 92f are fitted with the first spiral groove 91b. The plurality of second protrusions in the contact portion 92f are not fitted with the first spiral groove 91b and a second spiral groove (not shown) and are separated from the inner guide member 91. As a result, the upper side of the contact portion 92f is retained in the first spiral groove 91b, and the lower side of the contact portion 92f is not retained and is separated from the inner guide member 91.

[0017] The lower surface 93a of the lower belt case 93 pushes up the storage portion 92h. As a result, the multiple first projections 92a press against the upper wall surface of the first helical groove 91b, and the main surface of the contact portion 92f, particularly the end of the contact portion 92f on the side of the separation portion 92g, is inclined with respect to the central axis C9. On the other hand, the main surface of the storage portion 92h is approximately parallel to the central axis C9. Therefore, the main surface of the contact portion 92f and the main surface of the storage portion 92h extend in different directions. As described above, the contact portion 92f, the separation portion 92g, and the storage portion 92h are connected in this order along the longitudinal direction of the inner belt 92. The separation portion 92g is subjected to a force in the torsional direction and twists. Therefore, when transitioning between the separated state and the cylindrical configuration state described above, the inner belt 92 twists.

[0018] Specific embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings have been simplified as appropriate.

[0019] <Embodiment 1> Embodiment 1 will be described with reference to Figures 1-6. Figure 1 is an overall perspective view of the expandable device according to Embodiment 1. Figure 2 is a perspective view of the main part of the expandable device shown in Figure 1 with the upper belt case 6 removed. Figure 3 is a perspective view of the main part of the expandable device shown in Figure 2 with the cover 4 removed. Figure 4 is a perspective view of an example of an inner guide member according to Embodiment 1. Figure 5 is a cross-sectional view and an enlarged cross-sectional view of an example of an inner guide member shown in Figure 4 at the cutting line VV. Figure 6 is a diagram showing the operation of the expandable device according to Embodiment 1. For clarity, in Figure 1, a part of the outer belt 5 and a part of the front side of the upper belt case 6 are omitted from the illustration. Also, in Figures 2, 3 and 6, a part of the inner belt 2 is omitted from the illustration.

[0020] <Structure> As shown in Figures 1 and 3, the telescopic device 100 comprises a cylindrical structure 10 and an inner guide member 1. The telescopic device 100 according to this embodiment 1 further comprises a lower belt case 3, a cover 4, and an upper belt case 6.

[0021] The cylindrical structure 10 is expandable and contractible in the direction of its central axis C1 (in this case, the Z-axis direction). The cylindrical structure 10 comprises an outer belt 5 and an inner belt 2. In the cylindrical structure 10, the inner belt 2 is positioned inside the outer belt 5. The inner belt 2 and the outer belt 5 may be made of a flexible material. Such a material is, for example, steel.

[0022] The inner belt 2 comprises a plurality of first projections 2a (see Figure 6) arranged in a row along the longitudinal direction of the inner belt 2, a plurality of second projections (not shown) arranged in a row below the plurality of first projections 2a in the cylindrical structure 10, and a plurality of holes (not shown). Specifically, the first projections 2a and the second projections may protrude from the outer edge of the holes. The first projections 2a and the second projections extend in a cylindrical shape, and the diameters of the first projections 2a and the second projections may decrease from their base to their tip. In the cylindrical structure 10, the first projections 2a and the second projections protrude toward the inner guide member 1. The plurality of first projections 2a protrude toward the inner guide member 1 and have a shape that can be fitted into the first helical groove 1b.

[0023] The outer belt 5, like the inner belt 2, has multiple protrusions (not shown) arranged in two rows along the longitudinal direction of the outer belt 5, and multiple holes (not shown). Specifically, the multiple protrusions of the outer belt 5 may protrude from the outer edge of the holes. The multiple protrusions of the outer belt 5 extend in a cylindrical shape, and their diameter may decrease from the base to the tip. In the cylindrical structure 10, the multiple protrusions of the outer belt 5 protrude toward the inner guide member 1.

[0024] In the cylindrical structure 10, the inner belt 2 and the outer belt 5 engage with each other. Specifically, when the inner belt 2 and the outer belt 5 are wrapped around the inner guide member 1, the inner belt 2 and the outer belt 5 engage with each other by having multiple protrusions on the outer belt 5 insert into the corresponding multiple holes on the inner belt 2.

[0025] The inner guide member 1 is a cylindrical body positioned inside the cylindrical structure 10. As shown in Figure 4, a first helical groove 1b, a second helical groove 1c, and a flange 1d are formed on the outer circumferential surface 1a of the inner guide member 1. The first helical groove 1b and the second helical groove 1c are provided on the outer circumferential surface 1a, spaced apart from the flange 1d. As shown in Figure 4, the flange 1d is provided on the root side of the inner guide member 1 (here, in the negative Z-axis direction). The first helical groove 1b and the second helical groove 1c extend along the plurality of first protrusions 2a and plurality of second protrusions of the inner belt 2 in the cylindrical structure 10, respectively. Specifically, the first helical groove 1b extends along the plurality of first protrusions 2a in the cylindrical structure 10. The second helical groove 1c extends along the plurality of second protrusions of the inner belt 2 as described above. The first helical groove 1b and the second helical groove 1c are each capable of engaging with a plurality of first projections 2a and a plurality of second projections of the inner belt 2. The first helical groove 1b and the second helical groove 1c extend in parallel on the outer circumferential surface 1a.

[0026] The first helical groove 1b comprises a body 1ba and an end portion 1bb. The end portion 1bb extends from the body 1ba towards the root side of the inner guide member 1. The distance between the end portion 1bb and the body 1ba is small. Specifically, as shown in Figure 5, the width Lb of the end portion 1bb of the first helical groove 1b is wider than the width La of the body 1ba of the first helical groove 1b. For example, the width Lb of the end portion 1bb may gradually increase as one moves from the boundary 1bc between the end portion 1bb and the body 1ba towards the end portion 1bb.

[0027] The inner guide member 1 is held so as to be rotatable around the central axis C1 of the cylindrical structure 10. The central axis C1 of the cylindrical structure 10 may be the same as the central axis of the inner guide member 1. The inner guide member 1 rotates in one direction or the other around the central axis C1 of the cylindrical structure 10 by being supplied with driving force from a drive source such as a motor.

[0028] The cover 4 covers the inner guide member 1. The cover 4 is located inside the cylindrical structure 10. As shown in Figures 1 and 2, the cover 4 is a cylindrical body and has openings 4a and 4b on its outer circumferential surface. The opening 4b shown in Figure 1 is located above the opening 4a shown in Figure 2. The opening 4a is large enough for the inner belt 2 to be introduced to the inner guide member 1 and penetrates the wall of the cylindrical body of the cover 4. The opening 4b is large enough for the outer belt 5 to be introduced to the inner guide member 1 and penetrates the wall of the cylindrical body of the cover 4.

[0029] As shown in Figures 1 and 2, the lower belt case 3 houses the inner belt 2 in a supplyable manner. The lower belt case 3 is located outside the cover 4. The lower belt case 3 has a ring shape centered on the central axis C1 of the cylindrical structure 10. The lower belt case 3 comprises a bottom surface 3a and side walls 3b. The bottom surface 3a is preferably annular and substantially perpendicular to the central axis C1. The side walls 3b may rise from the outer edge of the bottom surface 3a. The side walls 3b may extend in an annular shape around the central axis C1. When the inner belt 2 is housed in the lower belt case 3, the bottom surface 3a supports the inner belt 2 housed in the lower belt case 3. In such a case, the inner belt 2 may be wound along the side walls 3b around the central axis C1.

[0030] As shown in Figure 1, the upper belt case 6 houses the outer belt 5 in a supplyable manner. The upper belt case 6 is located on the outside of the cover 4. The upper belt case 6 is provided above the lower belt case 3. The upper belt case 6 has a ring shape centered on the central axis C1 of the cylindrical structure 10.

[0031] <Operation> The telescopic device 100 can extend or retract the cylindrical structure 10. The operation of the telescopic device 100 in extending the cylindrical structure 10 will be described below. As shown in Figures 1 and 2, the inner guide member 1 rotates in one direction around the central axis C1. Then, the inner guide member 1 winds up the outer belt 5 and the inner belt 2. Subsequently, the outer belt 5 is fed from the upper belt case 6 through the opening 4b of the cover 4 to the inner guide member 1, and the inner belt 2 is fed from the lower belt case 3 through the opening 4a of the cover 4 to the inner guide member 1. The outer belt 5 and the inner belt 2 are wound around the inner guide member 1 in a spiral shape while engaging with each other. In other words, the structure transitions from a separated state in which the outer belt 5 and the inner belt 2 are housed in the upper belt case 6 and the lower belt case 3, respectively, to a cylindrical configuration state in which the outer belt 5 and the inner belt 2 are wound in a spiral shape. As a result, the cylindrical structure 10 is extended.

[0032] Next, the operation of the expandable / contractable device 100 in contracting the cylindrical structure 10 will be described. The inner guide member 1 rotates in the other direction around the central axis C1. As a result, the outer belt 5 and inner belt 2, which are already engaged and wound around each other, unwind. Subsequently, the outer belt 5 is pulled from the inner guide member 1 through the opening 4b of the cover 4 into the upper belt case 6, and the inner belt 2 is sent from the inner guide member 1 through the opening 4a of the cover 4 into the lower belt case 3. The outer belt 5 is stored in the upper belt case 6, and the inner belt 2 is stored in the lower belt case 3. In other words, the cylindrical structure transitions from a state in which the outer belt 5 and inner belt 2 are wound spirally to a separated state in which the outer belt 5 and inner belt 2 are stored in the upper belt case 6 and lower belt case 3, respectively. As a result, the cylindrical structure 10 contracts.

[0033] During the extension or contraction of the expandable / contractible device 100, it transitions between the separated state described above and the cylindrical configuration state described above. As shown in Figure 6, the inner belt 2 comprises a contact portion 2f, a separation portion 2g, and a storage portion 2h. The contact portion 2f, the separation portion 2g, and the storage portion 2h are arranged in this order along the longitudinal direction of the inner belt 2. The contact portion 2f is spirally wound around the outer belt 5 and contacts the inner guide member 1. The separation portion 2g extends from the end of the contact portion 2f to the lower belt case 3 and is separated from the inner guide member 1. The storage portion 2h extends from the end of the separation portion 2g and is housed in the lower belt case 3. The side wall 3b of the lower belt case 3 extends in an annular shape around the central axis C1. The storage portion 2h is wound along the inner wall surface of the side wall 3b.

[0034] Multiple first protrusions 2a on the contact portion 2f engage with the first helical groove 1b. Multiple second protrusions (not shown) on the contact portion 2f, particularly on the separation portion 2g side of the contact portion 2f, do not engage with the first helical groove 1b and the second helical groove 1c, and are separated from the inner guide member 1. As a result, the upper side of the contact portion 2f is secured to the first helical groove 1b, while the lower side of the contact portion 2f is not secured and is separated from the inner guide member 1.

[0035] The lower surface 3a of the lower belt case 3 pushes up the storage section 2h. However, as described above, the distance between the end 1bb of the first helical groove 1b and the main body 1ba is small. Therefore, the upper wall surface of the first helical groove 1b is located on the tip side of the inner guide member (in this case, in the positive Z-axis direction) than the upper wall surface of the first helical groove 91b shown in Figure 8. Therefore, the multiple first protrusions 2a are separated from the upper wall surface of the first helical groove 1b, or even if they come into contact with the upper wall surface of the first helical groove 1b, they hardly press against it. Even if the multiple first protrusions 2a press against the upper wall surface of the first helical groove 1b, the force with which the multiple first protrusions 2a press against the upper wall surface of the first helical groove 1b is small compared to the force with which the multiple first protrusions 92a press against the upper wall surface of the first helical groove 91b shown in Figure 8. Therefore, the main surface of the contact portion 2f is approximately parallel to the central axis C1. Similarly, the main surface of the storage portion 2h is approximately parallel to the central axis C1. As described above, the contact portion 2f, the separation portion 2g, and the storage portion 2h are connected in this order along the longitudinal direction of the inner belt 2. Therefore, the separation portion 2g is hardly subjected to force in the torsional direction. Thus, when transitioning between the separated state and the cylindrical configuration state described above, twisting of the inner belt 2 can be suppressed.

[0036] Furthermore, the width Lb of the end portion 1bb of the first helical groove 1b in this embodiment 1 is wider than the width La of the main body 1ba of the first helical groove 1b. This allows the upper wall surface of the first helical groove 1b to move toward the tip side of the inner guide member 1 (in this case, in the positive Z-axis direction). This further suppresses twisting of the inner belt 2.

[0037] <An example of a modified internal guide member> The inner guide member 11 shown in Figure 7 is a modified example of the inner guide member 1. The inner guide member 11 has the same configuration as the inner guide member 1, except for the first helical groove. The first helical groove 11b has the same configuration as the first helical groove 1b shown in Figures 4 and 5, except for the end. The first helical groove 11b comprises a body 11ba and an end 11bb. The end 11bb extends from the body 11ba towards the root side of the inner guide member 1. The helical pitch of the end 11bb of the first helical groove 11b is smaller than the helical pitch of the width of the body 11ba of the first helical groove 11b. For example, the helical pitch of the end 1bb may gradually decrease as you move from the boundary 11bc between the end 11bb and the body 11ba towards the end 1bb side. As a result, even when the telescopic device 100 is equipped with an inner guide member 11, the upper wall surface of the first helical groove 11b can move toward the tip side of the inner guide member 11 (in this case, in the positive Z-axis direction). Consequently, twisting of the inner belt 2 can be further suppressed.

[0038] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. Furthermore, the present invention may be implemented by appropriately combining the embodiments described above or one example thereof. For example, the second helical groove 1c shown in Figure 4 may have the same configuration as the first helical groove 1b. That is, the second helical groove 1c comprises a body and an end extending from the body toward the root side of the inner guide member 1. The distance between the end of the second helical groove 1c and the body of the second helical groove 1c is small. This makes it possible to suppress twisting of the inner belt 2, similar to the expansion and contraction device 100. [Explanation of Symbols]

[0039] 100 Telescopic device 10. Cylindrical structure 1, 11 Inner guide member 1a Outer surface 1b, 11b First spiral groove 1c, 11c Second spiral groove 1BA, 11BA main unit 1bb, 11bb end 1bc, 11bc boundary 1d flange 2 Inner belt 2a First projection 2f contact part 2g separation section 2h Storage area 3. Lower belt case 3a Bottom side 4 Covers 4a, 4b opening 5. Outer belt 6. Upper belt case 6a Bottom side La, Lb width

Claims

1. An expandable / contractable device comprising an expandable / contractable cylindrical structure and an internal guide member disposed inside the cylindrical structure, The cylindrical structure comprises an outer belt and an inner belt positioned inside the outer belt. The outer belt and the inner belt are provided with a plurality of first protrusions and holes arranged in a row in the longitudinal direction. The inner guide member has a first helical groove extending along the plurality of first protrusions, As the inner guide member rotates to one side, the outer belt and the inner belt are fed out and wound spirally while engaging with each other, causing the cylindrical structure to extend. As the inner guide member rotates to the other side, the outer belt and the inner belt are pulled in, causing them to unwind and the tubular structure to contract. The first helical groove comprises a main body and an end portion extending from the main body toward the root side of the inner guide member. The pitch of the helix at the end of the first helical groove is smaller than the pitch of the helix in the body of the first helical groove, or the width of the end of the first helical groove is wider than the width of the body of the first helical groove. Telescopic device.

2. The outer belt and the inner belt are provided with a plurality of second protrusions arranged in a single row in the longitudinal direction on the base side of the inner guide member, relative to the plurality of first protrusions. The inner guide member further comprises a second helical groove extending along the plurality of second protrusions, The second helical groove comprises a main body and an end portion extending from the main body toward the root side of the inner guide member. The helical pitch at the end of the second helical groove is smaller than the helical pitch of the body of the second helical groove, or the width at the end of the second helical groove is wider than the width of the body of the second helical groove. The expandable device according to claim 1.

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