Locking and unlocking mechanisms for telescopic tubes

Abstract

To provide a lock mechanism and a lock release mechanism for an expansion pipe.SOLUTION: There are provided with a lock mechanism which locks an inner pipe and an outer pipe immovably to and away from each other in a contraction movement direction and an expansion movement direction of the outer pipe for the inner pipe as a first direction (X1) and a second direction (X2), respectively, and a release mechanism which releases the lock, wherein the lock mechanism is configured to automatically lock by locking an elastically energized lock claw (8) to a lock part (9) when the outer pipe (7) is moved to a predetermined stop position (P) in the first direction (X1), and the release mechanism is configured to unlock the lock claw (8) through pressing of a release claw (11) by protruding the release claw (11) coupled to interlock the lock claw (8) from the inner pipe (6) and moving a release cylinder (10) provided on the outer pipe (7) to a release position (P2).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a locking mechanism and an unlocking mechanism for telescopic tubes used in folding workbenches and other fields.

Background Art

[0002] For example, in the case of a workbench that can be folded so that the top plate is in a semi-folded state, the divided left and right top plates are pivotally connected at the semi-folded portion in the center of the top plate so that the posture can be changed between a folded posture in which the left and right top plates are in a mountain shape and a deployed posture in which they are in a horizontal state. The left and right top plates are each supported by a leg frame body with casters.

[0003] At this time, by supporting the left and right top plates and the left and right leg frame bodies with telescopic members that can be telescopically extended and contracted, the posture change between the folded posture and the deployed posture can be smoothly performed. Therefore, a telescopic member formed by a linear shock absorber (damper) has been proposed (Patent Document 1).

[0004] However, in order to perform the posture change quickly with a light force, it is desirable to use a telescopic tube that allows free telescopic extension and contraction rather than a damper.

[0005] Therefore, it is preferable that the diagonal member is constituted by a telescopic tube in which an inner tube and an outer tube are slidably inserted, the inner tube is pivotally connected to the top plate, and the outer tube is pivotally connected to the leg frame body.

[0006] When the workbench is in the folded posture, the left and right leg frame bodies are overlapped in a close state, and the left and right top plates are overlapped in a substantially vertical posture and parallel to each other on the outside. At this time, the telescopic tube is in the longest extended state.

[0007] When changing the posture toward the deployed posture, the left and right top plates open in a mountain shape, and the left and right leg frame bodies move away from each other, and the telescopic tube gradually contracts.

[0008] When the workbench is extended, the left and right tabletops are extended horizontally, and the telescopic tubes extend diagonally from the leg frame towards the underside of the tabletops, representing the shortest retracted state. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 2899751 [Overview of the project] [Problems that the invention aims to solve]

[0010] Incidentally, since the workbench is used in its unfolded position with the worker standing on the tabletop, it is desirable to lock the telescopic tube so that it cannot be extended or retracted, thereby preventing the tabletop from accidentally shifting in the folding direction and ensuring safety during work.

[0011] Furthermore, in order to quickly change the posture from the unfolded position to the folded position, it is preferable to configure the device so that the lock can be released easily and quickly.

[0012] The present invention aims to provide a locking mechanism and an unlocking mechanism for a telescopic tube that solve the above-mentioned problems. However, the present invention is not limited to telescopic tubes that constitute diagonal members in a folding workbench, but can be widely applied to any telescopic tube that requires locking and unlocking, regardless of the technical field. [Means for solving the problem]

[0013] Therefore, in order to solve the above problems, the present invention provides an expandable tube consisting of an inner tube and an outer tube that are slidably fitted together in the expansion and contraction directions, wherein the contraction direction and extension direction of the outer tube relative to the inner tube are designated as a first direction and a second direction, respectively, and a locking mechanism is provided to lock the inner tube and the outer tube so that they cannot move relative to each other, and a release mechanism is provided to release the lock. The locking mechanism comprises a locking claw that is projected outward by an elastic biasing means through a guide hole in the inner tube, a locking start part formed at the end of the outer tube so as to push the locking claw into the guide hole when the outer tube is moved in the first direction, and a locking part formed on the outer tube so as to receive and lock the locking claw by facing the guide hole when the outer tube is moved further in the first direction to a predetermined stop position while the locking claw is pushed in. The release mechanism comprises a release claw located near the end of the outer tube locked in the stop position in a first direction and projecting outward through a through-hole in the inner tube by an elastic biasing means, and a release cylinder provided to be movable so as to project outward from the end of the outer tube in a first direction, wherein when the release cylinder is moved in the first direction, the release claw is pushed into the through-hole by a release operating part provided in the release cylinder, and when pushed in, an interlocking coupling means is provided to move the locking claw in a direction away from the locking part to release the lock, wherein when the unlocked outer tube is moved in a second direction, the release cylinder moves in accordance with the outer tube, but is provided with a release holding part that continues to push in the release claw until the locking part of the outer tube moves to a position where it is not locked by the locking claw.

[0014] In a preferred embodiment, the inner tube externally attaches and fixes a fixed cylinder portion that receives the locking start portion of the outer tube when the outer tube is moved in the first direction to the stop position, and the fixed cylinder portion is provided with an external through hole that allows the release claw to protrude outward, and when the release cylinder is moved to a release position that protrudes from the outer tube in the first direction, the end of the moving release cylinder forms a release start portion that pushes the release claw into the external through hole, and the inner circumference of the release cylinder after movement is provided with a release holding portion that maintains the pushed-in state of the release claw.

[0015] The interlocking coupling means is preferably composed of a spring material that connects the locking claw and the release claw to each other. In this case, the spring material is formed to be elastically swingable with its end extending in the first direction as a support portion, while being housed inside the inner tube.

[0016] Preferably, the release cylinder is connected to the outer tube via a follow-up moving mechanism. In this case, the follow-up moving mechanism is configured to move the release cylinder in the first direction to the release position while the outer tube is stopped at the stop position, and to move the release cylinder in the second direction in accordance with the outer tube when the outer tube is moved in the second direction while the release cylinder is stopped at the release position. [Effects of the Invention]

[0017] According to the present invention, when the telescopic tube 5 is retracted by moving the outer tube 7 in the first direction X1, the outer tube 7 can be automatically locked at the stop position P. To release the lock, the lock is easily released simply by moving the release cylinder 10 from the standby position P1 to the release position P2. Furthermore, while the release cylinder 10 remains in the release position P2, the outer tube 7 can be moved in the second direction X2, and the telescopic tube 5 can be extended. [Brief explanation of the drawing]

[0018] [Figure 1] The diagram illustrates a folding workbench using the telescopic tube of the present invention as a diagonal member. (A) is a perspective view in the folded position, (B) is a perspective view during a change in position, and (C) is a perspective view in the unfolded position. [Figure 2] Figure 1 shows the folding workbench from the front, with (A) being a front view in the folded position, (B) being a front view during the position change, and (C) being a front view in the unfolded position. [Figure 3] The diagram shows the operation of the expansion joints that make up the diagonal members. (A) is an enlarged front view showing the state during the change of posture from the folded position to the unfolded position, and (B) is an enlarged front view showing the state when it is in the unfolded position. [Figure 4]The figure shows the appearance of the telescopic tube according to an embodiment of the present invention. (A) is a perspective view for explaining the telescopic movement direction, (B) is a perspective view for explaining that when the outer tube is moved to the stop position, it is locked by the locking mechanism, and (C) is a perspective view for explaining that when the release cylinder is moved, the lock is released by the unlocking mechanism. [Figure 5] Regarding the locking mechanism provided in the inner tube, (A) is a perspective view showing the inner tube, the claw unit, and the fixed cylinder part in a disassembled state, (B) is a perspective view of the state where the claw unit is incorporated into the inner tube, (C) is a perspective view of the state where the fixed cylinder part is assembled to the inner tube, and (D) is an enlarged perspective view showing the claw unit. [Figure 6] Regarding the operation of the claw unit, (A) is a cross-sectional view showing the non-operating state, (B) is a cross-sectional view showing the state where the locking claw is pushed into the guide hole, and (C) is a cross-sectional view showing the state where the release claw is pushed into the outer through hole. [Figure 7] Regarding the release cylinder, (A) is a perspective view showing the inner tube and the release cylinder in a disassembled state, (B) is a perspective view of the state where the release cylinder is assembled to the inner tube, and (C) is a longitudinal cross-sectional view for explaining the movement range of the release cylinder. [Figure 8] Regarding the follow-up movement means, (A) is a cross-sectional view showing the state where the release cylinder is stopped at the standby position, (B) is a cross-sectional view for explaining that the release cylinder can move to the release position, and (C) is a cross-sectional view for explaining that the release cylinder can move following the inner tube from the release position. [Figure 9] The figure shows the operations of the locking mechanism and the unlocking mechanism. (A) is a cross-sectional view showing the state where the outer tube is moving in the first direction, (B) is a cross-sectional view showing the state where the outer tube has moved to the stop position and is locked by the locking mechanism, (C) is a cross-sectional view showing the state where the lock is released by the unlocking mechanism, and (D) is a cross-sectional view showing the operation of the follow-up movement means when the outer tube is moved in the second direction. [Figure 10] The figure shows a modified embodiment of the follow-up movement means. (A) is a cross-sectional view showing the state where it is locked by the locking mechanism, (B) is a cross-sectional view showing the state where the lock is released by moving the release cylinder to the release position, and (C) is a cross-sectional view showing the state when the outer tube starts to move in the second direction in the unlocked state.

Best Mode for Carrying Out the Invention

[0019] The preferred embodiments of the present invention will be described in detail below based on the drawings.

[0020] FIGS. 1 to 3 show an example of a folding workbench. The workbench 1 has a top plate 2 divided into left and right parts. The top plate 2 can be changed in posture between a folded posture in a mountain shape and an unfolded posture in a horizontal state. It is pivotally connected at the half-fold part in the center of the top plate. The left and right top plates 2 are respectively supported by leg frame bodies 3, 3 with casters, and the left and right leg frame bodies 3 and the top plate 2 are connected by diagonal members 4.

[0021] The diagonal member 4 is composed of a telescopic tube 5 in which an inner tube 6 and an outer tube 7 are slidably inserted. The inner tube 6 is pivotally connected to the top plate 2, and the outer tube 7 is pivotally connected to the leg frame body 3.

[0022] When the workbench 1 is in the folded posture, as shown in FIGS. 1(A) and 2(B), the left and right leg frame bodies 3, 3 are overlapped in a proximate state, and the left and right top plates 2 are overlapped in a substantially vertical posture and parallel to each other on the outside. At this time, the telescopic tube 5 is in the longest extended state.

[0023] When changing the posture toward the unfolded posture, as shown in FIGS. 1(B) and 2(B), the left and right top plates 2 open in a mountain shape, and the left and right leg frame bodies 3, 3 move in a direction away from each other, and the telescopic tube 5 gradually contracts.

[0024] When the workbench 1 is in the unfolded posture, as shown in FIGS. 1(C) and 2(C), the left and right top plates 2 are in a horizontally unfolded state and supported by the separated leg frame bodies 3, 3. The leg frame body 3 and the top plate 2 are connected by the telescopic tube 5 extending obliquely. At this time, the telescopic tube 5 is in the shortest contracted state.

[0025] Thus, the expansion joint 5 is expanded and contracted by the axial movement of the inner tube 6 and the outer tube 7 relative to each other. For the sake of explanation, the direction in which the outer tube 7 contracts relative to the inner tube 6 will be referred to as the first direction X1, and the direction in which it extends will be referred to as the first direction X2.

[0026] Therefore, in the case of the workbench 1 shown in the figure, as shown in Figure 3, when the posture is changed from a folded position to an unfolded position, the telescopic tube 5 is shortened as the outer tube 7 moves relative to the inner tube 6 in the first direction X1. Conversely, when the posture is changed from an unfolded position to a folded position, the telescopic tube 5 is shortened as the outer tube 7 moves relative to the inner tube 6 in the first direction X2. When the telescopic tube 5 is shortened, a locking mechanism is provided to lock the inner tube 6 and the outer tube 7 so that they cannot move relative to each other, and a release mechanism is provided to release the lock.

[0027] As shown in Figure 4(A), the outer tube 7 is fitted onto the inner tube 6 and is slidable in the first direction X1 and the second direction X2.

[0028] Therefore, as shown in Figure 4(B), when the end 7a of the outer tube 7 is moved in the first direction X1 to a predetermined stopping position P so that the expansion tube 5 is retracted to a predetermined length, a locking mechanism is provided in which a locking claw 8 protruding from the outer surface of the inner tube 6 engages with a locking part 9 such as a hole provided in the outer tube 7, thereby locking it.

[0029] A release cylinder 10 is provided near the end 7a of the outer tube 7. As shown in Figure 4(C), when the release cylinder 10 is moved to protrude from the outer tube 7, a release claw 11 provided on the tail end side of the inner tube 6 is pushed in, and the lock of the locking claw 8 is released in conjunction with this pushing, so that the outer tube 7 can move freely in the second direction X2, and the telescopic tube 5 becomes extendable.

[0030] In the case of the workbench 1 described above, as shown in Figure 3(B), when the top plates 2, 2 are extended, the outer tube 7 is moved in the first direction X1 and automatically locked by the locking mechanism when it reaches the stop position P. When folding the top plates 2, 2, the lock is released when the worker moves the release cylinder 10, and then the top plates 2, 2 can be lifted in the middle and folded in half to form a mountain shape. The only action required to release the lock is to move the release cylinder 10, and no further work is required. In this case, according to the illustrated configuration, the inner tube 6 is pivotally connected to the underside of the top plate 2, and the release cylinder 10 of the locked outer tube 7 faces the underside of the top plate 2, so the worker has the advantage of being able to easily operate the release cylinder 10 without being forced into a low posture.

[0031] (Technical configuration of the internal piping) Figures 5 and 6 show the components incorporated into the inner tube 6, relating to the configuration of the locking and unlocking mechanisms.

[0032] The locking claw 8 and the release claw 11 are provided on the spring material 12, thereby constituting a claw unit 13. The spring material 12 is formed by bending a leaf spring into a roughly U-shape, with the bent portion serving as a support portion 12a to create a pair of elastically swingable legs 12b, 12b, and the locking claw 8 and the release claw 11 are fixed so as to protrude outward from the legs 12b.

[0033] The spring material 12 is installed inside the inner tube 6 near the tail end, with the tip of the leg portion 12b facing the outer tube 7 (in other words, facing the second direction X2), and is fixed by elastically contacting the support portion 12a with the inner circumferential surface of the inner tube 6. At this time, the locking claw 8 and the release claw 11 are inserted through the guide hole 14 and through hole 15 provided in the inner tube 6, respectively, and protrude outwards (see Figures 5(A) and 5(B)).

[0034] A fixing cylinder portion 16 is fitted onto the tail end of the inner tube 6 and secured by fasteners 17 such as rivets. At this time, the fixing cylinder portion 16 is fixed with its end 16a positioned between the locking claw 8 and the release claw 11, and an external through hole 18 is provided to allow the release claw 11 to protrude outward (see Figure 5(C)).

[0035] In the illustrated embodiment, the diagonal member 4 of the workbench 1 is formed by the telescopic tube 5, and the inner tube 6 is pivotally connected to the top plate 2. Therefore, a pivot hole 19 for inserting a pivot pin or the like is provided at the tail end of the fixed cylindrical portion 16, but this does not limit the present invention.

[0036] With the above configuration, as shown in Figure 6(A), the spring material 12, by its leg portion 12b, constitutes a resilient biasing means 20 that causes the locking claw 8 to protrude outward from the guide hole 14 toward the outside of the inner tube 6, and the release claw 11 to protrude outward from the through hole 15 and the outer through hole 18 toward the outside of the fixed cylinder portion 16. The fixed cylinder portion 16, by its end portion 16a, constitutes a stopper 21 that abuts against and receives the end portion 7a of the outer tube 7 when the outer tube 7 is moved in the first direction X1, stopping it at the aforementioned stop position P. This defines the distance L1 between the locking claw 8 and the stopper 21, and the distance L2 between the stopper 21 and the release claw 11. As shown in the figure, by forming inclined surfaces facing the first direction, a push guide 8a for the locking claw 8 and a push guide 11a for the release claw 11 are provided, the outer diameter of the inner tube 6 is D1, and the outer diameter of the fixed cylinder portion 16 is D2.

[0037] As shown in Figure 6(B), the locking claw 8 is biased by the elastic biasing means 20 to protrude from the guide hole 14. When the push-in guide 8a receives a thrust force in the first direction X1, the leg portion 12b of the spring material 12 elastically deforms, causing it to be pushed into the guide hole 14.

[0038] Similarly, as shown in Figure 6(C), the release claw 11 is biased by the elastic biasing means 20 to protrude from the outer through hole 18. However, when the push guide 11a receives a thrust force in the first direction X1, the leg portion 12b of the spring material 12 elastically deforms, causing it to be pushed into the outer through hole 18. As shown in the figure, when the release claw 11 is pushed in, the leg portion 12b extending from the support portion 12a of the spring material 12 elastically swings and tilts, causing the locking claw 8 to move in the same tilting direction. In other words, the leg portion 12b constitutes an interlocking coupling means 22, and when the release claw 11 is pushed into the outer through hole 18, the locking claw 8 is also configured to remain pushed into the guide hole 14 in conjunction with it.

[0039] (Technical configuration regarding the external casing) Figures 7 and 8 show the components incorporated into the outer tube 7, relating to the configuration of the locking and unlocking mechanisms.

[0040] The outer tube 7 has a locking portion 9 formed by a hole or recess at a predetermined distance from the end 7a in the first direction X1, and a release cylinder 10 is fitted onto the vicinity of the end including the locking portion 9. In this case, the release cylinder 10 is fitted onto the outer tube 7 so as to be able to protrude from the end 7a toward the first direction X1. In the illustrated example, a projection 24 such as a pin inserted into the release cylinder 10 is slidably inserted into a slot 23 provided in the outer tube 7, so that the release cylinder 10 can move between a standby position P1 in which it does not protrude from the end 7a of the outer tube 7 and a release position P2 in which it protrudes by a predetermined amount, as shown in Figure 7(C). In the illustrated example, a headed bolt is screwed into the threaded hole of the release cylinder 10, and the tip of the bolt shaft inserted into the slot 23 constitutes the projection 24, but the configuration is not limited to this.

[0041] As shown in Figure 8(A), the inner diameter d1 of the outer tube 7 is formed to slide against the outer circumferential surface of the inner tube 6, which has an outer diameter D1 as described above, and the inner diameter d2 of the release cylinder 10 is formed to slide against the outer circumferential surface of the fixed cylinder portion 16, which has an outer diameter D2 as described above.

[0042] As shown in Figure 8(B), the distance between the end 7a of the outer tube 7 and the locking portion 9 is defined by distance L3, and the distance between the tip 10a of the release cylinder 10 and the end 7a of the outer tube 7 when moved to the release position P2 is defined by distance L4. Distance L3 is approximately equal to the distance L1 between the locking claw 8 and the stopper 21 in the inner tube 6 described above, that is, L3 ≈ L1. Distance L4 is greater than the distance L2 between the stopper 21 and the release claw 11 in the inner tube 6 described above, that is, L4 > L2.

[0043] Therefore, as will be described later, when the telescopic tube 5 is retracted, the outer tube 7 slides along the outer surface of the inner tube 6 and moves in the first direction X1. When the end 7a of the outer tube 7 is received by the stopper 21 of the fixed cylinder portion 16 fixed to the inner tube 6 and stops at the stopping position P, the locking portion 9 faces the locking claw 8, and thus they lock together. Prior to this, in order to start the locking operation, the locking start portion 25, which is formed by the end 7a of the outer tube 7, passes over the locking claw 8, thereby pushing the locking claw 8 into the guide hole 14.

[0044] Similarly, as will be described later, when the outer tube 7 is stopped at the stop position P, and the release cylinder 10 is moved from the standby position P1 to the release position P2, the release starter part 26 formed by the end of the release cylinder 10 passes through the release claw 11, thereby pushing the release claw 11 into the outer through hole 18. When the release cylinder 10 is moved to the release position P2, a release holding part 27 is provided on the inner circumference of the protruding part of the release cylinder 10 that protrudes from the end 7a of the outer tube 7 to hold the released claw 11 in the pushed-in state.

[0045] Incidentally, the relationship between the slot 23 and the projection 24 is such that when the release cylinder 10 is in the standby position P1, the projection 24 faces the first end 23a of the slot 23 located in the second direction X2, and when the release cylinder 10 is in the release position P2, the projection 24 faces the second end 23b of the slot 23 located in the first direction X1.

[0046] As a result, as shown in Figure 3(C), the slot 23 and projection 24 allow the release cylinder 10 to move from the standby position P1 to the release position P2. In this state, when the outer tube 7 is moved in the second direction X2, the second end 23b of the slot 23 pulls the projection 24, thereby forming a follow-up movement means 28 that moves the release cylinder 10 along with the outer tube 7 while holding it in the release position P2. The follow-up movement means 28 does not necessarily have to be composed of the slot 23 and projection 24; it is sufficient if it allows the release cylinder 10 to move in the first direction X1, but when the outer tube 7 is moved in the second direction, it moves along with the release cylinder 10 in the second direction while holding it in the release position P2.

[0047] (Operation of the locking and unlocking mechanisms) Figure 9 shows the operation of the locking mechanism and the unlocking mechanism described above. As shown in Figures 9(A) and 9(B), when the telescopic tube 5 is retracted, the outer tube 7 slides along the outer surface of the inner tube 6 and moves in the first direction X1. The end 7a of the outer tube 7 is received by the stopper 21 of the fixed cylinder portion 16 fixed to the inner tube 6 and stops at the stop position P. Before reaching the stop position P, the locking start portion 25 formed on the end 7a of the outer tube 7 pushes in the locking claw 8, and as soon as it reaches the stop position P, the locking claw 8, which is elastically biased by the spring material 12, enters the lock portion 9. As a result, the outer tube 7 and the inner tube 6 are automatically locked so that they cannot move relative to each other.

[0048] To release the lock, the release cylinder 10 is moved from the standby position P1 to the release position P2 by manual operation, as shown in Figure 9(C). Before reaching the release position P2, the release starter 26 pushes in the release claw 11, and even after reaching the release position P2, the release holding 27 maintains the pushed-in state of the release claw 11.

[0049] When the release claw 11 is pressed in, the interlocking coupling means 22 of the spring material 12 disengages the locking claw 8 from the locking part 9, and therefore the lock is released. In other words, the outer tube 7 is in a state where it can move freely in the second direction X2, and at this time, the projection 24 of the follow-up moving means 28 faces the second end 23b of the slot 23. Therefore, in the case of the workbench 1 shown in Figures 1 to 3, as the top plates 2, 2 are folded into a mountain shape from the unfolded position to the folded position, the outer tube 7 is moved in the second direction X2, and the telescopic tube 5 is extended.

[0050] In this case, as shown in Figure 9(D), when the outer tube 7 is moved in the second direction X2, the release cylinder 10 is pulled by the following moving means 28 and moves in the second direction X2. The release holding portion 27 of the release cylinder 10 is formed over a predetermined length in the direction of movement, so when it has moved by that predetermined length, it detaches from the release claw 11. In this case, before the release holding portion 27 detaches from the release claw 11, the locking portion 9 of the outer tube 7 is moved to a position away from the locking claw 8, so the outer tube 7 moves to a position where the telescopic tube 5 is in a predetermined extended state.

[0051] (Modified embodiment of the follow-me movement mechanism) This shows a modified embodiment of the follow-up movement mechanism, in which the slot 23 is formed to be longer toward the end 7a of the outer tube 7, as indicated by the reference numeral E, than the slot in the above embodiment, and a second end 23c is formed in the extended portion. The other configurations are the same as in the above embodiment.

[0052] Therefore, as shown in Figure 10(A), with the end 7a of the outer tube 7 in contact with the stopper 21 at stop position P, and the locking claw 8 engaged with the locking part 9 in a locked state, as shown in Figure 10(B), when the release cylinder 10 is moved from the standby position P1 to the release position P2, the release claw 11 is pushed in by the release starter part 26 of the release cylinder 10 and held in the pushed-in state by the release holding part 27, disengaging the locking claw 8 from the locking part 9 and releasing the lock. This point is also the same as in the above embodiment.

[0053] However, in the modified embodiment, as shown in Figure 10(B), when the release cylinder 10 is moved to the release position P2, the projection 24 does not reach the second end 23c of the slot 23, but is configured to stop at a position spaced apart from the second end 23c, as indicated by the symbol E.

[0054] Therefore, as shown in Figure 10(C), when the outer tube 7 is moved in the second direction X2, the release cylinder 10 does not immediately move in accordance with the outer tube 7. Instead, when the outer tube 7 moves by a predetermined distance indicated by the symbol M in the second direction X2, the second end 23c of the slot 23 comes into contact with the projection 24, causing the release cylinder 10 to move along with it.

[0055] Thus, according to this modified embodiment, the release cylinder 10 is not moved until the outer tube 7 moves a predetermined distance M, thereby moving the locking portion 9 to a position sufficiently far from the locking claw 8. In other words, during this time, the release holding portion 27 of the release cylinder 10, which is in a stationary state, maintains the unlocked state of the locking claw 8, making it possible to make the dimensions of the release holding portion 27 smaller and allowing the entire device to be made compact. [Explanation of symbols]

[0056] X1 First direction (contraction movement direction) X2 2nd direction (extension movement direction) P Stop position P1 Standby position P2 release position 1 Workbench 2 Top plate 3 leg frame 4 Diagonals 5 Telescopic tube 6 Inner tube 7 Outer tube 7a End 8. Locking claws 8a Push-in guide 9 Locking part 10 Release tube 11 Release Claw 11a Push-in guide 12 Spring material 12a Support part 12b Legs 13 Claw Unit 14 Guide holes 15 through hole 16 Fixed cylinder part 16a End 17 Fixtures 18 Outer hole 19 Pivot hole 20 Elastic biasing means 21 Stopper 22 Interlocking connection means 23 slots 23a First end 23b Second end 23c Second end (modified embodiment) 24 protrusions 25 Locking and starting section 26 Release Start Unit 27 Release holding part 28. Follow-me movement means

Claims

1. In an expandable tube consisting of an inner tube and an outer tube that are slidably fitted together in the expansion and contraction directions, the contraction direction and extension direction of the outer tube relative to the inner tube are defined as a first direction (X1) and a second direction (X2), respectively, and a locking mechanism is provided to lock the inner tube and outer tube so that they cannot move relative to each other, and a release mechanism is provided to release the lock. The locking mechanism comprises a locking claw (8) projecting outward through a guide hole (14) in the inner tube (6) by a resilient biasing means (29), a locking starter (25) formed on the end (7a) of the outer tube (7) to push the locking claw into the guide hole when the outer tube (7) is moved in a first direction (X1), and a locking part (9) formed on the outer tube to receive and lock the locking claw by facing the guide hole when the outer tube is further moved in the first direction to a predetermined stop position (P) with the locking claw pushed in. The release mechanism comprises a release claw (11) located near the end (7a) of the outer tube locked in the stop position (P) in the first direction (X1), and which is made to protrude outward through a through hole in the inner tube by a resilient biasing means (20), and a release cylinder (10) provided to be movable so as to protrude outward from the end (7a) of the outer tube toward the first direction. The release claw (11) is pushed into the through hole by a release starter (26) provided on the release cylinder when the release cylinder (10) is moved in the first direction (X1), and when pushed in, an interlocking coupling means (22) is provided to move the locking claw (8) in a direction away from the locking part (9) to release the lock. The locking mechanism and unlocking mechanism for an expandable tube is characterized in that the release cylinder (10) moves in accordance with the outer tube (7) when the unlocked outer tube (7) is moved in a second direction (X2), but is provided with a release holding part (27) that continues to push in the release claw (11) until the locking part (9) of the outer tube moves to a position where it is not engaged by the locking claw (8).

2. The inner tube (6) externally attaches and fixes a fixing cylinder portion (16) that receives the locking start portion (25) of the outer tube when the outer tube (7) is moved to the stop position (P) in the first direction, and the fixing cylinder portion is provided with an external through hole (18) that allows the release claw (11) to protrude outward. The locking mechanism and unlocking mechanism for an expandable tube according to claim 1, characterized in that the release cylinder (10) is provided with a release starting portion (26) that pushes the release claw into the outer through hole with the end of the moving release cylinder when it moves to a release position (P2) that protrudes from the outer tube toward a first direction, and a release holding portion (27) that maintains the pushed-in state of the release claw with the inner circumference of the release cylinder after it has moved.

3. The interlocking coupling means (22) is composed of a spring material (12) that connects the locking claw (8) and the release claw (11) to each other. The locking mechanism and unlocking mechanism in the telescopic tube according to claim 1, characterized in that the spring material is formed to be elastically swingable with an end extending in the first direction (X1) as a support portion (12a) while being housed inside the inner tube (6).

4. The release cylinder (10) is connected to the outer tube (7) via a follow-up moving means (28), The locking mechanism and unlocking mechanism for an expandable tube according to claim 2, characterized in that the following moving means (28) is configured to move the release cylinder (10) in the first direction (X1) to the release position (P2) while the outer tube is stopped at the stop position (P), and when the outer tube (7) is moved in the second direction (X2) while the release cylinder is stopped at the release position, the release cylinder (10) is configured to move in the second direction (X2) in accordance with the outer tube (7).

Images