JP6356212B2 - Fall prevention device - Google Patents

Description

  The present invention relates to a fall prevention device.

  Patent Document 1 discloses a conventional overturn prevention device. This fall prevention device includes a damper and is attached between the upper surface of the furniture installed on the floor and the ceiling. In this damper, the damping force generated during the contracting operation is larger than the damping force generated during the extending operation, and the reaction force is urged in the extending direction. In this overturn prevention device, when the furniture is tilted due to shaking such as an earthquake, a damping force generated during the contraction operation of the damper acts on the furniture, and the tilt of the furniture can be suppressed to prevent the overturn.

Japanese Patent Laying-Open No. 2015-6330

  However, the fall prevention device of Patent Document 1 requires a force that exceeds the damping force generated during the contraction operation when the damper is contracted to be attached to or detached from the top surface of the furniture and the ceiling. In addition, when the damper is contracted, the overturn prevention device expands vigorously unless a force is applied in the direction in which the damper is always contracted against the reaction force biased in the extending direction. Thus, this fall prevention device has difficulty in attaching and detaching operations.

  This invention is made | formed in view of the said conventional situation, Comprising: It is set as the problem which should be solved to provide the fall prevention apparatus which can perform attachment and removal easily.

  The fall prevention device of the present invention includes a damper and is attached between an article installed on the installation surface and the ceiling. In the damper, the damping force generated during the contracting operation is larger than the damping force generated during the extending operation, and the reaction force is urged in the extending direction. The damper has a piston rod and a center rod. The piston rod is formed with an insertion hole extending on the central axis. The center rod is inserted into the insertion hole of the piston rod, and the positional relationship with the piston rod changes. When the positional relationship between the piston rod and the center rod is changed, the damper is switched to a damping mode, a free mode, or a lock mode. In the damping mode, the damper is telescopic, and a damping force larger than the damping force generated during the extension operation is generated during the contraction operation. In the free mode, the damper is freely extendable and a damping force smaller than the damping force generated during the contracting operation in the damping mode is generated during the contracting operation. The lock mode prevents or decelerates the extension operation of the damper due to the reaction force biased in the extension direction.

  The overturn prevention device is attached between the article and the ceiling in a state where the damper is in a damping mode by changing the positional relationship between the piston rod and the center rod of the damper. Then, the damper provided in the fall prevention device generates a damping force larger than the damping force generated during the extension operation during the contraction operation while the reaction force acts in the extension direction. For this reason, when the article is tilted due to a shake such as an earthquake, this fall prevention device can suppress the tilt by the damping force generated during the contraction operation of the damper acting on the article and prevent the article from falling.

  In addition, when the damper is placed in the free mode by changing the positional relationship between the piston rod and the center rod of the damper, this overturn prevention device reduces the damping force generated during the contracting operation of the damper to the damping force generated during the contracting operation in the damping mode. Smaller than. That is, this fall prevention device can easily contract the damper with a small force when the damper is set to the free mode. As described above, the fall prevention device can easily contract the damper when the damper is placed in the free mode, for example, when the article is attached to or removed from the ceiling.

  In addition, when the damper is placed in the lock mode by changing the positional relationship between the piston rod and the center rod of the damper, the overturn prevention device prevents or decelerates the extension operation of the damper due to the reaction force biased in the extension direction. . For this reason, this fall prevention device can prevent a damper from extending unexpectedly or vigorously when the damper is contracted to be attached or removed between the article and the ceiling. That is, when the fall prevention device is attached between the article and the ceiling, the damper can be gradually extended, so that the fall prevention device can be attached in an appropriate state. Moreover, when removing the fall prevention device attached between the article and the ceiling, the shrunk damper does not extend unexpectedly or vigorously, so that the removal can be easily performed.

  Therefore, the fall prevention device can be easily attached and detached.

  In the overturn prevention device of the present invention, the damper may have a cylinder, a piston, a first flow path, a check valve, and a second flow path. The cylinder has a bottomed cylindrical shape. The piston is slidably accommodated in the cylinder. Further, the piston partitions the inside of the cylinder into a rod side chamber and a bottom side chamber. The piston is connected to the tip of the piston rod. When the positional relationship between the piston rod and the center rod is changed, the first flow path is switched to a communication state or a blocking state. The first flow path communicates the rod side chamber and the bottom side chamber in the communication state. In addition, the first flow path blocks communication between the rod side chamber and the bottom side chamber in the blocked state. The check valve is provided in the first flow path. This check valve allows the flow of the working liquid from the rod side chamber to the bottom side chamber and prevents the reverse flow. When the positional relationship between the piston rod and the center rod is changed, the second flow path is switched to the first communication state, the second communication state, or the cutoff state. The second flow path communicates the rod side chamber and the bottom side chamber via the orifice in the first communication state. The orifice imparts a resistance to the flow of the working liquid when the damper is contracted to generate a damping force. The second flow path communicates the rod side chamber and the bottom side chamber via the communication path in the second communication state. The communication path has a larger flow area than the orifice. The second flow path has a larger flow rate of the working liquid flowing in the second communication state than in the first communication state. The second flow path blocks communication between the rod side chamber and the bottom side chamber in the blocked state. The damper switches to the attenuation mode when the first flow path is switched to the communication state and the second flow path is switched to the first communication state. Further, the damper switches to the free mode when the second flow path is switched to the second communication state. Further, the damper switches to the lock mode when the first flow path and the second flow path are switched to the shut-off state.

  In this case, the overturn prevention device changes the positional relationship between the piston rod and the center rod of the damper to switch the state of the first flow path and the second flow path, so that the damper is in a damping mode, a free mode, or a lock. You can switch to one of the modes.

  In the overturn prevention device of the present invention, the first flow path of the damper may include a first flow rate change unit. The first flow rate changing unit gradually decreases the flow rate of the working liquid flowing through the first flow path in the process of changing the positional relationship between the piston rod and the center rod to switch the first flow path from the communication state to the shut-off state. . In this case, the damper can adjust the flow rate of the working liquid flowing through the first flow path by the first flow rate change unit. The extension operation of the damper due to the repulsive force biased in the extension direction of the damper becomes slower as the flow rate of the working liquid flowing through the first flow path is decreased. For this reason, this fall prevention device adjusts the extension speed by the repulsive force urged in the extension direction of the damper by adjusting the flow rate of the working liquid flowing through the first flow path at the first flow rate change unit. Therefore, the damper can be gradually extended and attached in an appropriate state between the article and the ceiling.

  In the overturn prevention device of the present invention, the second flow path of the damper may include a second flow rate change unit. The second flow rate change unit gradually changes the flow rate of the working liquid flowing through the second flow path in the process of changing the positional relationship between the piston rod and the center rod and switching the second flow path from the second communication state to the shut-off state. Decrease. In this case, the damper can adjust the flow rate of the working liquid flowing through the second flow path by the second flow rate change unit. The extension operation of the damper due to the repulsive force biased in the extension direction of the damper becomes slower as the flow rate of the working liquid flowing through the second flow path is decreased in the state where the first flow path is shut off. For this reason, this fall prevention device adjusts the extension speed by the repulsive force urged in the extension direction of the damper by adjusting the flow rate of the working liquid flowing through the second flow path at the second flow rate change unit. Therefore, the damper can be gradually extended and attached in an appropriate state between the article and the ceiling.

  In the fall prevention device of the present invention, the positional relationship between the piston rod and the center rod can be changed by relatively moving along the central axis. In this case, an insertion hole penetrating along the central axis is formed in the piston rod, inserted into this insertion hole, and the protruding length of the center rod protruding from the rear end portion of the piston rod is operated to change the protruding length. Thus, the positional relationship between the piston rod and the center rod can be easily changed.

  In the fall prevention device of the present invention, the positional relationship between the piston rod and the center rod can be changed by relatively rotating around the central axis. In this case, an insertion hole penetrating along the central axis is formed in the piston rod, inserted into this insertion hole, and the projecting portion of the center rod projecting from the rear end portion of the piston rod is operated to rotate. The positional relationship with the center rod can be easily changed.

  The fall prevention device of the present invention may include a cam and a lever. The cam is rotatably supported on the rear end side of the piston rod. When this cam rotates, the center rod moves along the central axis. The lever is connected to the cam. In this fall prevention device, as the lever moves around the rotation axis and approaches the piston rod, the cam rotates and the positional relationship between the piston rod and the center rod changes, and the damper is in the damping mode, lock mode, Switches to the order of free mode. In this case, when the lever is brought close to the piston rod so as to grip the lever and the piston rod, the damper enters a free mode, and the damper can be easily contracted while holding the lever and the piston rod.

  In the fall prevention device of the present invention, the damper may have a pin member. The piston rod has an insertion hole extending along the central axis. The center rod extends along the central axis with the second flow path opening in the tip surface. In a state where the damper is most contracted, the pin member is inserted from the bottom chamber side into the insertion hole opened in the distal end surface of the piston rod, blocks the insertion hole, and blocks the second flow path. In this case, the fall prevention device prevents the extension operation due to the reaction force urged in the extension direction with the first flow path and the second flow path in the closed state in the state where the damper is contracted the most. Can be maintained. For this reason, this fall prevention device can hold a damper in the most contracted state, and can pack or carry it.

  Here, the articles include furniture, refrigerators, bookcases, showcases, server racks, beds in which a plurality of beds are connected in the vertical direction, large televisions, and the like that may fall over due to earthquakes or the like.

It is a side view which shows the state which attached the fall prevention apparatus of Embodiment 1 and 3 between the upper surface of furniture, and the ceiling. It is a side view which shows the motion of the 1st lever and the 2nd lever at the time of removing the fall prevention apparatus of Embodiment 1 and 3 from between the upper surface of furniture, and a ceiling. It is a side view which shows the state which reduced the damper of the fall prevention apparatus of Embodiment 1 and 2 attached between the upper surface and ceiling of furniture. It is sectional drawing which shows the principal part of the damper of the fall prevention apparatus of Embodiment 1. It is sectional drawing which shows the damper which is a damping mode in the fall prevention apparatus of Embodiment 1. FIG. It is sectional drawing which shows the damper which is a lock mode in the fall prevention apparatus of Embodiment 1. FIG. It is sectional drawing which shows the damper which is free mode in the fall prevention apparatus of Embodiment 1. FIG. It is sectional drawing which shows the damper which is a lock mode in the fall prevention apparatus of Embodiment 2. FIG. It is sectional drawing which shows the damper which is free mode in the fall prevention apparatus of Embodiment 3. FIG. It is sectional drawing which shows the state with which the 3rd through-hole and the 2nd notch part overlapped in the lock | rock mode in the fall prevention apparatus of Embodiment 3. FIG. It is sectional drawing which shows the state with which the 1st through-hole and the 1st notch part overlapped in the lock | rock mode in the fall prevention apparatus of Embodiment 3. FIG. It is a side view which shows the state which the damper contracted most in the fall prevention apparatus of Embodiment 4. It is principal part sectional drawing of the state which the damper contracted most in the fall prevention apparatus of Embodiment 4. FIG. In the overturn prevention apparatus of Embodiment 5, it is sectional drawing which shows the principal part of the damper which is a damping mode. 14A is a sectional view taken along line XX in FIG. 14, FIG. 14B is a sectional view taken along line YY in FIG. 14, and FIG. 14C is a sectional view taken along line ZZ in FIG. In the overturn prevention apparatus of Embodiment 5, it is sectional drawing which shows the principal part of the damper which is free mode. 16A is a cross-sectional view taken along the line XX in FIG. 16, FIG. 16B is a cross-sectional view taken along the line Y-Y in FIG. 16, and FIG. In the overturn prevention apparatus of Embodiment 5, it is sectional drawing which shows the principal part of the damper which is a lock mode. 18A is a cross-sectional view taken along the line XX in FIG. 18, FIG. 18B is a cross-sectional view taken along the line Y-Y in FIG. 18, and FIG.

  Embodiments 1 to 5 embodying the overturn prevention device of the present invention will be described with reference to the drawings.

<Embodiment 1>
As shown in FIGS. 1 and 2, at least one or more fall prevention devices of Embodiment 1 are attached between the upper surface of the furniture F and the ceiling C. The furniture F is installed on the floor surface with the back surface facing a wall surface W extending vertically from a floor surface (not shown). Moreover, this furniture F is a rectangular parallelepiped shape, has a door, a drawer, etc. which are not shown in the front (right side surface in FIGS. 1-3), and can accommodate clothing, jewelry, etc. inside. The furniture F has a rectangular shape in which the horizontal cross-sectional shape is long in the left-right direction (the depth direction in FIGS. 1 to 3). When the fall prevention device is not attached, the furniture F may be tilted forward and fall down due to shaking such as an earthquake (right direction in FIGS. 1 to 3).

The overturn prevention device includes a damper 10, a pair of base portions 30 </ b> A and 30 </ b> B, and an operation unit 50.
4 to 7, the damper 10 includes a cylinder 11, a rod guide 12, a piston rod 13, a center rod 14, a piston 15, a first flow path 21, a check valve 16, and a second flow path 22. Have. The cylinder 11 has a bottomed cylindrical shape. The cylinder 11 is filled with hydraulic oil and compressed gas. The cylinder 11 is provided with a connecting member 17 for connecting a first base portion 30A, which will be described later, to a bottom side end portion (a lower end portion in FIGS. 4 to 7).

  The rod guide 12 has an insertion hole that seals the open end of the cylinder 11 and allows the piston rod 13 to be slidably inserted at the center. The piston rod 13 is slidably inserted into the insertion hole of the rod guide 12 and is inserted into the cylinder 11 so as to be reciprocally movable in the central axis direction. The piston rod 13 protrudes from the opening end of the cylinder 11 and extends on the central axis of the cylinder 11. The piston rod 13 is formed with an insertion hole 13A extending on the central axis. The piston rod 13 is attached to a rear end portion (an upper end portion in FIGS. 4 to 7) with a connector 17 that connects a second base portion 30B described later.

  The center rod 14 is inserted into the insertion hole 13A of the piston rod 13 so as to be slidable along the central axis. That is, the piston rod 13 and the center rod 14 move relatively along the central axis. The center rod 14 is longer than the piston rod 13. The center rod 14 is formed with a concave portion that goes around the outer peripheral surface in an intermediate portion. The center rod 14 has a packing P1 fitted in the recess. By this packing P1, the space between the piston rod 13 and the center rod 14 is made fluid-tight, and the hydraulic oil is prevented from leaking from between the piston rod 13 and the center rod 14. The center rod 14 is subjected to a reaction force that moves backward (upward in FIGS. 4 to 7) with respect to the piston 15 by the compressed gas sealed in the cylinder 11.

  The piston 15 has an annular shape. In the piston 15, the tip end portion of the piston rod 13 is inserted into the central through hole, and the tip end portion of the piston rod 13 is connected. The piston 15 is slidably accommodated in the cylinder 11. The piston 15 partitions the inside of the cylinder 11 into a rod side chamber R1 and a bottom side chamber R2.

  The first flow path 21 includes a first through hole 21A, a second through hole 21B, a groove portion 21C, and a communication hole 21D. 21 A of 1st through-holes are formed in the rear-end part (upper end part in FIGS. 4-7) side of the piston 15 of the piston rod 13, and it is a piston between the outer peripheral surface of the piston rod 13, and an internal peripheral surface. The rod 13 extends in a straight line in the direction orthogonal to the central axis of the rod 13 and penetrates. The first through hole 21 </ b> A has one end opened on the outer peripheral surface of the piston rod 13 exposed in the rod side chamber R <b> 1 and the other end opened on the inner peripheral surface of the piston rod 13.

  The second through-hole 21 </ b> B is formed in a portion connecting the piston 15 of the piston rod 13, and the piston is formed between the outer peripheral surface and the inner peripheral surface of the tip portion of the piston rod 13 connecting the piston 15. The rod 13 extends in a straight line in the direction orthogonal to the central axis of the rod 13 and penetrates. The second through-hole 21 </ b> B has one end opened on the outer peripheral surface of the piston rod 13 where the piston 15 is connected, and the other end opened on the inner peripheral surface of the piston rod 13. The first through hole 21 </ b> A and the second through hole 21 </ b> B have a predetermined interval in the central axis direction of the piston rod 13.

  The groove portion 21 </ b> C is formed in the center rod 14, and extends by denting the outer peripheral surface of the center rod 14 along a central axis direction of the center rod 14 in a straight line. The groove portion 21 </ b> C is a retracted position where the center rod 14 is most retracted with respect to the piston rod 13, and the rear end portion communicates with the first through hole 21 </ b> A opened on the inner peripheral surface of the piston rod 13. The tip portion communicates with the second through hole 21B opened in the surface (see FIG. 5).

  The communication hole 21 </ b> D is formed in the piston 15, and communicates from the inner peripheral surface of the piston 15 to the tip surface facing the bottom side chamber R <b> 2 of the piston 15. The communication hole 21D opened in the inner peripheral surface of the piston 15 communicates with the second through hole 21B. Thus, the first flow path 21 communicates the rod side chamber R1 and the bottom side chamber R2 at the retracted position where the center rod 14 is most retracted with respect to the piston rod 13 (see FIG. 5).

  The check valve 16 is provided so as to open and close an opening portion opened in the front end surface of the piston 15 of the communication hole 21D. The check valve 16 includes a valve body 16A that opens and closes an opening, and a leaf spring 16B that applies an elastic force in a direction in which the valve body 16A is pressed from the bottom side chamber R2. The check valve 16 is configured such that when the center rod 14 is retracted most with respect to the piston rod 13 and the first flow path 21 communicates the rod-side chamber R1 and the bottom-side chamber R2, the rod-side chamber R1 is connected to the bottom-side chamber R2. Allow the flow of hydraulic oil and block the reverse flow (see FIG. 5).

  The second flow path 22 includes a third through hole 22A, a central flow path 22B, an orifice 22C, and a communication path 22D. 22 A of 3rd through-holes are formed in the rear-end part (upper end part in FIGS. 4-7) rather than the piston 15 of the piston rod 13, and it is a piston between the outer peripheral surface of the piston rod 13, and an internal peripheral surface. The rod 13 extends in a straight line in the direction orthogonal to the central axis of the rod 13 and penetrates. The third through hole 22 </ b> A has one end opened on the outer peripheral surface of the piston rod 13 exposed in the rod side chamber R <b> 1 and the other end opened on the inner peripheral surface of the piston rod 13.

  The central flow path 22B is formed in the center rod 14, opens to the tip end surface (the lower end surface in FIGS. 4 to 7) of the center rod 14, and rearward (upward in FIGS. 4 to 7) on the central axis. Extends a predetermined length. The orifice 22 </ b> C is formed in the center rod 14 and penetrates between the inner peripheral surface of the central flow path 22 </ b> B and the outer peripheral surface of the center rod 14. The orifice 22C communicates with the third through hole 22A at the retracted position where the center rod 14 is most retracted with respect to the piston rod 13 (see FIG. 5).

  The communication passage 22D is formed in the center rod 14 and penetrates between the inner peripheral surface of the rear end portion (the upper end portion in FIGS. 4 to 7) of the central flow path 22B and the outer peripheral surface of the center rod 14. Yes. The communication path 22D has a larger flow area than the orifice 22C. The communication passage 22D communicates with the third through hole 22A at the forward position where the center rod 14 is most advanced with respect to the piston rod 13 (see FIG. 7). The orifice 22 </ b> C and the communication path 22 </ b> D have a predetermined interval in the central axis direction of the center rod 14.

  The pair of base portions 30 </ b> A and 30 </ b> B are a first base portion 30 </ b> A that makes contact with the upper surface of the furniture F and a second base portion 30 </ b> B that makes contact with the ceiling C, as shown in FIGS. 1 to 3. 30 A of 1st base parts are rotatably connected with respect to the damper 10 by the coupling tool 17 attached to the bottom part side edge part (in FIGS. 4-7) of the cylinder 11 of the damper 10. As shown in FIG. The second base portion 30B is rotatably connected to the damper 10 by a connector 17 attached to the rear end portion (the upper end portion in FIGS. 4 to 7) of the piston rod 13 of the damper 10.

As shown in FIGS. 1 to 7, the operation unit 50 includes a cam 53, a first lever 51, a second lever 52, and a torsion coil spring 54.
As shown in FIGS. 4 and 5, the cam 53 is pivotally supported by a pivot shaft 31 provided on the rear end portion (upper end portion in FIG. 4) side of the piston rod 13. The rotating shaft 31 is configured to rotatably connect the second base portion 30B to the damper 10 on the rear end portion (upper end portion in FIG. 4) side of the piston rod 13. The cam 53 has a substantially egg shape having a disc-shaped center portion 53A and a convex portion 53B formed continuously in one direction from the center portion 53A. The cam 53 has the first base portion 30A below the second base portion 30B and the center axis of the damper 10 extending in the vertical direction, with the rear end surface (see FIG. 4 is in contact with the upper end surface. When the cam 53 rotates in the clockwise direction from the state in which the rear end surface of the center rod 14 is in contact with the outer peripheral surface located at the boundary between the center portion 53A and the convex portion 53B, the center rod 14 is inserted into the piston rod 13. Gradually push into hole 13A. And the front-end | tip part of the convex part 53B of the cam 53 contact | abuts to the rear-end surface of the center rod 14, and the center rod 14 becomes the advance position (refer FIG. 7) most advanced with respect to the piston rod 13. FIG. As described above, in the damper 10, the positional relationship between the piston rod 13 and the center rod 14 is changed by the rotation of the cam 53.

  The first lever 51 includes a first connecting portion 51A and a first lever body 51B. As shown in FIG. 4 and FIG. 5, the first connecting portion 51A is in a state where the central axis of the damper 10 extends in the vertical direction with the first base portion 30A positioned below the second base portion 30B, and The center rod 14 extends in a band shape obliquely upward to the right continuously from the upper right portion of the cam 53 at the retracted position where the center rod 14 is most retracted with respect to the piston rod 13. Further, in this state, the first lever main body 51B is continuous with the first connecting portion 51A, extends and extends diagonally downward to the right so as to be away from the piston rod 13, and the tip is curved diagonally upward to the right. .

  The second lever 52 has a rotation center portion 52A, a second connecting portion 52B, and a second lever main body 52C. The rotation center 52 </ b> A has a disk shape and is pivotally supported on the rotation shaft 31. As shown in FIGS. 4 and 5, the second connecting portion 52B is in a state where the central axis of the damper 10 extends in the vertical direction with the first base portion 30A positioned below the second base portion 30B, and The center rod 14 extends in a band shape obliquely upward to the left continuously from the upper left portion of the rotation center portion 52A at the retracted position where the center rod 14 is most retracted with respect to the piston rod 13. Further, in this state, the second lever main body 52C is continuous with the second connecting portion 52B, extends and extends diagonally downward to the left so as to be separated from the piston rod 13, and the tip portion is curved diagonally upward to the left. .

  The torsion coil spring 54 has a coil portion 54A and a pair of arm portions 54B extending from both ends of the coil portion 54A. The coil portion 54 </ b> A is inserted through the rotation shaft 31 provided on the rear end side of the piston rod 13. One end of the pair of arm portions 54B is in contact with the inner surface of the first lever body 51B on the rotating shaft 31 side, and the other end is in contact with the inner surface of the second lever body 52C on the rotating shaft 31 side. ing. The torsion coil spring 54 provides an elastic force in the direction in which the first lever 51 and the second lever 52 open.

  Next, the damping mode, the lock mode, and the free mode of the damper 10 in the fall prevention device configured as described above will be described.

<Attenuation mode>
In the overturn prevention device, as shown in FIGS. 4 and 5, the first lever body 51 </ b> B and the second lever body 52 </ b> C spread outwardly by the elastic force of the torsion coil spring 54 (from the central axis of the piston rod 13). When the center rod 14 is farthest away, the rear end surface of the center rod 14 comes into contact with the outer peripheral surface located at the boundary between the central portion 53A and the convex portion 53B of the cam 53, and the center rod 14 is in the retracted position where it is most retracted with respect to the piston rod 13. Become. In this state, the groove portion 21C formed in the center rod 14 has a rear end portion communicating with the first through hole 21A and a front end portion communicating with the second through hole 21B. Further, the orifice 22C formed in the center rod 14 communicates with the third through hole 22A. As described above, the first flow path 21 is in a communication state in which the first through hole 21A and the second through hole 21B communicate with the groove portion 21C, and the rod side chamber R1 and the bottom side chamber R2 communicate with each other. 22 is in a first communication state in which the rod side chamber R1 and the bottom side chamber R2 communicate with each other via an orifice 22C communicated with the third through hole 22A.

  When the damper 10 contracts in this state, the hydraulic oil flows from the bottom side chamber R2 to the rod side chamber R1 through the second flow path 22 in the first communication state. At this time, in the damper 10, the orifice 22 </ b> C provides resistance to the hydraulic oil flowing through the second flow path 22 in the first communication state, and generates a damping force. The first flow path 21 is blocked by the check valve 16 from flowing hydraulic oil from the bottom side chamber R2 to the rod side chamber R1. On the other hand, in this overturn prevention device, when the damper 10 extends in this state, the hydraulic oil flows from the rod side chamber R1 to the bottom side chamber R2 through the first flow path 21 in the communication state. At this time, the resistance to the hydraulic fluid flowing through the first flow path 21 in the communication state is much smaller than the resistance provided by the orifice 22C to the hydraulic fluid flowing through the second flow path 22 during the contraction operation.

  Thus, in this overturn prevention device, as shown in FIGS. 4 and 5, the first lever main body 51B and the second lever main body 52C are most outwardly spread (the farthest away from the central axis of the piston rod 13). In this state, the damper 10 is telescopic and enters a damping mode in which a damping force greater than the damping force generated during the extension operation is generated during the contraction operation.

<Lock mode>
In this overturn prevention device, as shown in FIG. 6, the first lever body 51B and the second lever body 52C are moved from the outermost state to the piston rod 13 in the direction approaching the piston rod 13, and the first lever When the main body 51B and the second lever main body 52C are rotated, the rear end surface of the center rod 14 comes into contact with the outer peripheral surface on the nearer side than the front end portion of the convex portion 53B of the cam 53, and the center rod 14 is moved from the retracted position. Moves forward to the middle position. In this state, the groove portion 21 </ b> C formed in the center rod 14 is positioned forward (downward in FIG. 6) than the first through hole 21 </ b> A. A third through hole 22A is located between the orifice 22C and the communication path 22D. As described above, the first flow path 21 is in a blocked state without the first through hole 21A communicating with the groove portion 21C, and the second flow path 22 is configured such that the third through hole 22A does not communicate with the orifice 22C and the communication path 22D. It is cut off.

  Thus, in this overturn prevention device, as shown in FIG. 6, the first lever main body 51B and the second lever main body 52C are in the direction approaching the piston rod 13 from the state where the first lever main body 51B and the second lever main body 52C expand outward. When the second lever main body 52C is rotated about the rotation axis 31, the damper 10 is blocked between the rod side chamber R1 and the bottom side chamber R2 because the first flow path 21 and the second flow path 22 are blocked. The hydraulic oil cannot move and cannot expand and contract. That is, the damper 10 is in a lock mode in which the extension operation due to the reaction force biased in the extension direction is blocked.

<Free mode>
In this overturn prevention device, as shown in FIG. 7, the first lever body 51B and the second lever body 52C are rotated by rotating the first lever body 51B and the second lever body 52C around the rotation shaft 31. When approaching along the central axis of the piston rod 13, the rear end surface (upper end surface in FIG. 7) of the center rod 14 comes into contact with the outer peripheral surface of the tip portion of the convex portion 53 </ b> B of the cam 53, and the center rod 14 contacts the piston rod 13. On the other hand, it becomes the most advanced forward position. In this state, the groove portion 21 </ b> C formed in the center rod 14 moves forward (downward in FIG. 7) from the second through hole 21 </ b> B. Further, the communication passage 22D formed in the center rod 14 communicates with the third through hole 22A. As described above, the first flow path 21 is in the cut-off state without the first through hole 21A and the second through hole 21B communicating with the groove portion 21C, and the second flow path 22 is communicated with the third through hole 22A. A second communication state is established in which the rod-side chamber R1 and the bottom-side chamber R2 communicate with each other via the communication passage 22D.

  When the damper 10 is expanded and contracted in this state, the hydraulic oil flows from the bottom side chamber R2 to the rod side chamber R1 via the second flow path 22 that is in the second communication state. At this time, since the flow path area of the communication path 22D is larger than that of the orifice 22C, the flow rate of the hydraulic oil in the second flow path 22 is larger than that in the first communication state.

  Thus, in this overturn prevention device, the first lever body 51B and the second lever body 52C are rotated about the rotation shaft 31 so that the first lever body 51B and the second lever body 52C are connected to the piston rod 13. The damper 10 is telescopic, and enters a free mode in which a damping force smaller than the damping force generated during the contracting operation in the damping mode is generated during the contracting operation.

<Attachment and removal of fall prevention device>
As described above, before the fall prevention device including the damper 10 that can be switched to any one of the attenuation mode, the lock mode, and the free mode is installed between the upper surface of the furniture F and the ceiling C, the first lever main body. When the first lever body 51B and the second lever body 52C are brought close to the piston rod 13 so as to grip the 51B, the second lever body 52C, and the piston rod 13, the damper 10 enters the free mode, and the first lever body 51B, The damper 10 can be easily contracted with a small force while holding the two-lever main body 52C and the piston rod 13.

  When the fall prevention device is attached between the upper surface of the furniture F and the ceiling C, the second base portion 30B is extended from the contracted state of the damper 10 while the damper 10 is extended by a reaction force biased in the extending direction. Is brought into contact with the ceiling C. At this time, since the damper 10 can be set to the lock mode to prevent the extension operation and the damper 10 can be gradually extended, the collision sound of the second base portion 30B with the ceiling C can be reduced. In addition, as shown in FIG. 1, when the fall prevention device is attached between the upper surface of the furniture F and the ceiling C, the damper 10 is set to the lock mode to prevent the extension operation and gradually extend the damper 10. By adjusting the contact position of the second base portion 30B with the ceiling C to an appropriate position, the upper surface of the furniture F and the ceiling are adjusted so that the inclination angle of the damper 10 with respect to the vertical line is in the range of 15 ° to 25 °. It can be attached between C.

  When the fall prevention device is mounted between the upper surface of the furniture F and the ceiling C, the damper 10 is placed in a damping mode, so that a reaction force acts in the extension direction and occurs during the extension operation during the contraction operation. A damping force larger than the damping force to be generated is generated. For this reason, when the furniture F tilts due to shaking such as an earthquake, this fall prevention device suppresses the tilt by the damping force generated during the contraction operation of the damper 10 acting on the furniture F, thereby preventing the furniture F from falling. Can do.

  When the fall prevention device attached between the upper surface of the furniture F and the ceiling C is removed, the first lever body 51B, the second lever body 52C, and the piston rod 13 are gripped as shown in FIGS. When the first lever body 51B and the second lever body 52C are brought close to the piston rod 13, the damper 10 enters the free mode, and the damper 10 is held while holding the first lever body 51B, the second lever body 52C, and the piston rod 13. Can be easily contracted with a small force. At this time, if the damper 10 is set to the lock mode with the damper 10 contracted, the damper 10 does not extend unexpectedly or vigorously, so that the removal can be easily performed.

<Embodiment 2>
As shown in FIG. 8, the fall prevention device of the second embodiment is different from the first embodiment in the shape of the cam 153 of the operation unit 150. Other configurations are the same as those of the first embodiment, and the same configurations are denoted by the same reference numerals and detailed description thereof is omitted.

  The cam 153 has a central part 153A and a first convex part with respect to a substantially oval shape having a disc-shaped central part 153A and a first convex part 153B formed continuously in one direction from the central part 153A. This is a shape in which a second convex portion 153C is formed in which one outer peripheral surface extending from the boundary portion with the portion 153B toward the tip portion of the first convex portion 153B protrudes outward. The second convex portion 153C has a substantially triangular shape that is smaller than the first convex portion 153B in a side view when viewed along the direction in which the rotation shaft 31 extends, and the tip portion is curved outward. It is formed with a surface.

  The cam 153 has the first base portion 30A below the second base portion 30B and the center axis of the damper 10 extending in the vertical direction. 8 is in contact with the upper end surface. When the cam 153 rotates in the clockwise direction from the state in which the rear end surface of the center rod 14 is in contact with the outer peripheral surface located at the boundary between the center portion 153A and the second convex portion 153C, the center rod 14 is moved in the clockwise direction. The rear end surface of the center rod 14 gets over the tip end of the second convex portion 153C while being gradually pushed into the insertion hole 13A, and then the center rod 14 is gradually moved from the piston rod 13 insertion hole 13A by the reaction force applied to the center rod 14. While being pushed out, the rear end surface of the center rod 14 comes into contact with the concave portion 153D between the second convex portion 153C and the first convex portion 153B, and the center rod 14 becomes an intermediate position advanced from the retracted position. When the cam 153 rotates in the clockwise direction from this state, the tip of the first convex portion 153B of the cam 153 is brought to the rear end surface of the center rod 14 while the center rod 14 is gradually pushed into the insertion hole 13A of the piston rod 13. The center rod 14 comes into contact with the piston rod 13 in the most advanced position. Thus, in the damper 10, the positional relationship between the piston rod 13 and the center rod 14 is changed by the rotation of the cam 153.

  In the fall prevention device configured as described above, the rear end surface of the center rod 14 is in contact with the concave portion 153D between the second convex portion 153C and the first convex portion 153B of the cam 153, and the center rod 14 is located at a position beyond the retracted position. At the advanced intermediate position, the groove portion 21C formed in the center rod 14 is positioned forward (downward in FIG. 8) from the first through hole 21A. A third through hole 22A is located between the orifice 22C and the communication path 22D. As described above, the first flow passage 21 is in a blocked state without the first through hole 21A communicating with the groove portion 21C, and the second flow passage 22 is not communicated with the orifice 22C and the communication passage 22D. Is shut off.

  Thus, in this overturn prevention device, as shown in FIG. 8, the first lever main body 51B and the second lever main body 52C are in the direction approaching the piston rod 13 from the state where the first lever main body 51B and the second lever main body 52C expand outward. When the second lever main body 52C is rotated around the rotation shaft 31, and the rear end surface of the center rod 14 is brought into contact with the concave portion 153D between the second convex portion 153C and the first convex portion 153B of the cam 153, In the damper 10, since the first flow path 21 and the second flow path 22 are blocked, the hydraulic oil cannot move between the rod side chamber R <b> 1 and the bottom side chamber R <b> 2 and cannot expand and contract. That is, the damper 10 is in a lock mode in which the extension operation due to the reaction force biased in the extension direction is blocked.

  Even when the damper 10 is in the lock mode and the elastic force of the torsion coil spring 54 tries to rotate the first lever 51 and the second lever 52 around the rotation shaft 31 in the opening direction, the reaction force applied to the center rod 14 The rear end surface of the center rod 14 is pressed against the concave portion 153D between the second convex portion 153C and the first convex portion 153B of the cam 153, and the rear end portion of the center rod 14 cannot get over the second convex portion 153C. . For this reason, the damper 10 of this fall prevention device can hold the lock mode.

<Embodiment 3>
As shown in FIGS. 9 to 11, the overturn prevention device of the third embodiment includes a first notch 21 </ b> E in which the first flow path 121 provided in the damper 110 is a first flow rate change unit, and the second The point from which the flow path 122 is equipped with the 2nd notch 22E which is a 2nd flow volume change part differs from Embodiment 1. FIG. Other configurations are the same as those of the first embodiment, and the same configurations are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 9, this overturn prevention device is formed with a second cut portion 22 </ b> E cut into a V-shape that extends forward and continues to the communication path 22 </ b> D formed in the center rod 114. . The second cut portion 22E gradually decreases in depth from the front end of the communication path 22D toward the front (downward in FIG. 9). In this overturn prevention device, the first lever body 51B and the second lever body 52C are rotated about the rotation axis so that the first lever body 51B and the second lever body 52C are along the central axis of the piston rod 13. By bringing them closer together, the damper 110 is positioned at the advanced position where the center rod 114 is most advanced with respect to the piston rod 13, and enters the free mode. When the first lever main body 51B and the second lever main body 52C are spread away from the piston rod 13 from this state, the center rod 114 moves backward with respect to the piston rod 13 as shown in FIG. The third through hole 22A overlaps the second cut portion 22E. As the center rod 114 moves backward with respect to the piston rod 13, the damper 110 moves through the second flow path 122 by moving the overlapping position of the third through hole 22 </ b> A and the second notch 22 </ b> E. The flow rate of hydraulic oil gradually decreases. During this time, since the first flow path 121 is shut off, the damper 110 decreases as the flow rate of hydraulic oil that can flow through the second flow path 122 from the rod side chamber R1 toward the bottom side chamber R2 decreases. The extension speed due to the repulsive force urged in the extension direction is slow.

  For this reason, this overturn prevention device brings the first lever main body 51B and the second lever main body 52C close to the central axis of the piston rod 13 and puts the damper in the free mode. The extension speed by the repulsive force urged in the extension direction of the damper 110 is adjusted by expanding the two-lever body 52C away from the piston rod 13, or the third through hole 22A and the second notch It is possible to switch to the lock mode in which the second flow path 122 is blocked by eliminating the overlap with 22E and the expansion and contraction of the damper is prevented.

  Further, as shown in FIG. 11, this overturn prevention device moves the first lever body 51 </ b> B and the second lever body 52 </ b> C away from the piston rod 13 from the state where the first flow path 121 and the second flow path 122 are blocked. When expanded in this way, the center rod 114 is further retracted (raised in FIG. 11), and the first through hole 21A overlaps the first cut portion 21E. As the center rod 114 moves backward with respect to the piston rod 13, the damper 110 moves through the first flow path 21 as the overlapping position of the first through hole 21 </ b> A and the first notch 21 </ b> E moves. The flow rate of hydraulic oil gradually increases. The extension speed of the damper 110 due to the repulsive force biased in the extension direction of the damper 110 as the flow rate of the hydraulic oil that can flow through the first flow path 121 from the rod side chamber R1 toward the bottom side chamber R2 increases. Will be faster.

  For this reason, this overturn prevention device connects the first lever body 51B and the second lever body 52C to the piston from the state where the first flow path 121 and the second flow path 122 are blocked and the expansion and contraction of the damper 110 is blocked. The extension speed due to the repulsive force urged in the extension direction of the damper 110 can also be adjusted by the degree of expansion that extends away from the rod 13.

  As described above, this overturn prevention device adjusts the extension speed due to the repulsive force biased in the extension direction of the damper 110 according to the degree of expansion of the first lever body 51B and the second lever body 52C in the lock mode. Since the damper 110 can be prevented from expanding and contracting, the damper 110 can be gradually extended and attached in an appropriate state between the upper surface of the furniture F and the ceiling C.

<Embodiment 4>
As shown in FIGS. 12 and 13, the overturn prevention device of the fourth embodiment is inserted into the insertion hole 13 </ b> A opened at the distal end surface of the piston rod 13 from the bottom side chamber R <b> 2 when the damper 210 is in the most contracted state. The point which has the free piston 70 which comprised the pin member 71 which block | closes 13A and interrupts | blocks the 2nd flow path 22 is different from Embodiment 1. FIG. Other configurations are the same as those of the first embodiment, and the same configurations are denoted by the same reference numerals and detailed description thereof is omitted.

  In this overturn prevention device, a free piston 70 is slidably accommodated in a cylinder 11 on the bottom side of the cylinder 11 (lower side in FIGS. 12 and 13) than the piston 15. In the free piston 70, a packing P2 is externally fitted in a groove that goes around the outer peripheral surface. Compressed gas is sealed on the bottom side of the cylinder 11 (lower side in FIGS. 12 and 13) than the free piston 70, and operates on the open end side of the cylinder 11 (upper side in FIGS. 12 and 13) than the free piston 70. Oil is enclosed. In the free piston 70, a cylindrical pin member 71 projects from the center of the side surface on the piston 15 side. The tip of the pin member 71 is spherical. Further, the outer diameter dimension of the pin member 71 is the same as the inner diameter dimension of the insertion hole 13 </ b> A opened in the distal end surface of the piston rod 13.

  As shown in FIG. 12, in this overturn prevention device, when the damper 210 is contracted in the free mode, the pin member 71 is inserted into the insertion hole 13A opened in the distal end surface of the piston rod 13, and the insertion hole 13A is sealed. The second flow path 22 is blocked. For this reason, this fall prevention device will be in the state which interrupted the 1st channel 21 and the 2nd channel 22, the extension operation by the reaction force urged in the extension direction is blocked, and the most contracted state is held. . In this state, the fall prevention device can be packed or transported.

<Embodiment 5>
As shown in FIGS. 14 to 19, the overturn prevention device according to the fifth embodiment changes the positional relationship by causing the piston rod 313 and the center rod 314 of the damper 310 to rotate relative to each other around the central axis, thereby reducing the damping mode. The point of switching to either the free mode or the lock mode is different from the first embodiment. Other configurations are the same as those of the first embodiment, and the same configurations are denoted by the same reference numerals and detailed description thereof is omitted.

  The damper 310 of this overturn prevention device has a cylinder 11, a rod guide (not shown), a piston rod 313, a center rod 314, a piston 15, a first flow path 321, a check valve 16, and a second flow path 322. . The center rod 314 is inserted into the insertion hole 313A of the piston rod 313 so as to be rotatable around the central axis. That is, the piston rod 313 and the center rod 314 rotate relatively around the central axis. The center rod 314 and the piston rod 313 protrude from the piston 15 toward the bottom side chamber R2.

  As shown in FIGS. 14 and 15, the first flow path 321 includes a first through hole 21A, a second through hole 21B, a central flow path 322B, a first communication path 301, a second communication path 302, and a communication hole 21D. It is constituted by. 21 A of 1st through-holes are formed in the back end part side rather than the piston 15 of the piston rod 313, and the direction between the outer peripheral surface and inner peripheral surface of the piston rod 313 is orthogonal to the central axis of the piston rod 313. It extends in a straight line and penetrates. One end of the first through-hole 21A opens to the outer peripheral surface of the piston rod 313 exposed in the rod-side chamber R1, and the other end opens to the inner peripheral surface of the piston rod 313.

  The second through hole 21 </ b> B is formed in a portion connecting the piston 15 of the piston rod 313, and the piston is formed between the outer peripheral surface and the inner peripheral surface of the tip portion of the piston rod 313 connecting the piston 15. The rod 313 extends in a straight line in the direction perpendicular to the central axis of the rod 313 and penetrates. The second through hole 21 </ b> B has one end opened on the outer peripheral surface of the piston rod 313 where the piston 15 is connected, and the other end opened on the inner peripheral surface of the piston rod 313. The first through hole 21 </ b> A and the second through hole 21 </ b> B have a predetermined interval in the central axis direction of the piston rod 13.

  The central flow path 322B is formed at the tip of the center rod 314 so as to extend on the central axis. The first communication path 301 is formed in the center rod 314 and penetrates between the inner peripheral surface of the rear end portion (upper end portion in FIG. 14) of the central flow path 322B and the outer peripheral surface of the center rod 14. . The first communication path 301 is formed at a position where the center rod 314 communicates with the first through hole 21A formed in the piston rod 313 at a predetermined rotational position where the center rod 314 rotates about the central axis with respect to the piston rod 313. The second communication path 302 is formed in the center rod 314 and passes between the inner peripheral surface of the intermediate portion of the central flow path 322B and the outer peripheral surface of the center rod 314. The second communication path 302 has a second through hole formed in the piston rod 313 when the center rod 314 rotates around the central axis with respect to the piston rod 313 and the first communication path 301 communicates with the first through hole 21A. It is formed at a position communicating with the hole 21B.

  The communication hole 21 </ b> D is formed in the piston 15, and communicates from the inner peripheral surface of the piston 15 to the tip surface facing the bottom side chamber R <b> 2 of the piston 15. The communication hole 21D opened in the inner peripheral surface of the piston 15 communicates with the second through hole 21B. As described above, the first flow path 321 communicates the rod-side chamber R1 and the bottom-side chamber R2 at a predetermined rotational position where the center rod 314 rotates about the central axis with respect to the piston rod 313.

  The second flow path 322 is in a first communication state (see FIGS. 14 and 15) configured by the first through hole 21A, the third through hole 322A, the central flow path 322B, the first communication path 301, and the orifice 322C. And a second communication state (see FIGS. 16 and 17) configured by the first through hole 21A, the third through hole 322A, the central flow path 322B, the third communication path 303, and the fourth communication path 304. ing. The third through hole 322A is formed on the tip end side of the piston 15 of the piston rod 313, and straight between the outer peripheral surface and the inner peripheral surface of the piston rod 313 in a direction perpendicular to the central axis of the piston rod 313. It extends through the line. The third through hole 322A has one end opened on the outer peripheral surface of the piston rod 313 exposed in the bottom chamber R2, and the other end opened on the inner peripheral surface of the piston rod 313. As shown in FIGS. 14 and 15, the orifice 322 </ b> C is formed in the center rod 314. The orifice 322 </ b> C is formed between the inner peripheral surface of the front end portion (lower end portion in FIG. 14) and the outer peripheral surface of the center rod 314. It penetrates between. In the orifice 322C, the center rod 314 rotates around the central axis with respect to the piston rod 313, the first communication path 301 communicates with the first through hole 21A, and the second communication path 302 communicates with the second through hole 21B. At this time, the piston rod 313 is formed at a position communicating with the third through hole 322A. As described above, the second flow path 322 is connected to the rod side chamber R1 in the first communication state in which the first through hole 21A, the first communication path 301, the central flow path 322B, the orifice 322C, and the third through hole 322A communicate with each other. The bottom side chamber R2 is communicated.

  As shown in FIGS. 16 and 17, the third communication path 303 is formed in the center rod 314, and the inner peripheral surface of the rear end portion (upper end portion in FIG. 16) of the central flow path 322 </ b> B and the center rod 314. It penetrates between the outer peripheral surfaces. The third communication path 303 is formed at a position shifted from the first communication path 301 around the central axis by 120 degrees. Therefore, when the piston rod 313 is rotated 120 degrees in the counterclockwise direction from the state where the first communication path 301 communicates with the first through hole 21A, the third communication path 303 communicates with the first through hole 21A. The flow passage area of the third communication passage 303 is equal to the flow passage area of the first through hole 21A.

  The fourth communication passage 304 is formed in the center rod 314 and passes between the inner peripheral surface of the front end portion (lower end portion in FIG. 16) of the central flow path 322B and the outer peripheral surface of the center rod 314. Similar to the relationship between the first communication path 301 and the third communication path 303, the fourth communication path 304 is formed at a position shifted from the orifice 322C by 120 degrees around the central axis. Therefore, when the piston rod 313 is rotated 120 degrees counterclockwise from the state where the orifice 322C communicates with the third through hole 322A (the state where the first communication path 301 communicates with the first through hole 21A), The communication path 304 communicates with the third through hole 322A. The fourth communication path 304 has a larger flow area than the orifice 322C. Thus, the second flow path 322 is the rod in the second communication state in which the first through hole 21A, the third communication path 303, the central flow path 322B, the fourth communication path 304, and the third through hole 322A communicate with each other. The side chamber R1 and the bottom side chamber R2 are communicated.

  Next, the damper damping mode, free mode, and lock mode in the fall prevention device configured as described above will be described.

<Attenuation mode>
In this overturn prevention device, as shown in FIGS. 14 and 15, the center rod 314 is rotated with respect to the piston rod 313 to bring the first flow path 321 into the communication state and the second flow path 322 into the first communication state. To. When the damper 310 contracts in this state, the hydraulic fluid flows from the bottom side chamber R2 to the rod side chamber R1 via the second flow path 322 in the first communication state. At this time, in the damper 310, the orifice 322C imparts resistance to the hydraulic fluid flowing through the second flow path 322, and generates a damping force. The first flow path 321 is blocked by the check valve 16 from flowing hydraulic oil from the bottom side chamber R2 to the rod side chamber R1. On the other hand, in this overturn prevention device, when the damper extends in this state, the hydraulic oil flows through the first flow path 321 from the rod side chamber R1 to the bottom side chamber R2. At this time, the resistance to the hydraulic oil flowing through the first flow path 321 is much smaller than the resistance imparted by the orifice 322C to the hydraulic oil flowing through the second flow path 322 in the first communication state during the contraction operation. Thus, the damper 310 is extendable and becomes a damping mode in which a damping force larger than the damping force generated during the extension operation is generated during the contraction operation.

<Free mode>
In this overturn prevention device, as shown in FIGS. 16 and 17, when the center rod 314 is rotated 120 degrees counterclockwise with respect to the piston rod 313 from the state of the damping mode, the second flow path 322 is second. It becomes a communication state. When the damper is expanded and contracted in this state, the hydraulic oil flows from the bottom side chamber R2 to the rod side chamber R1 via the second flow path 322 in the second communication state. At this time, since the flow area of the fourth communication path 304 is larger than that of the orifice 322C, the flow rate of the working oil flowing through the second flow path 322 in the second communication state is the second flow path 322 in the first communication state in the attenuation mode. The flow rate of hydraulic fluid flowing through Thus, the damper 310 is extendable and becomes a free mode in which a damping force smaller than the damping force generated during the contracting operation in the damping mode is generated during the contracting operation.

<Lock mode>
In this overturn prevention device, as shown in FIGS. 18 and 19, the center rod 314 is rotated with respect to the piston rod 313 to a rotational position different from the damping mode and the free mode, and the first flow path 321 and the second flow path are set. If 322 makes the rod side chamber R1 and the bottom side chamber R2 not communicate with each other, the damper 310 cannot expand and contract, and a lock mode is established in which an extension operation due to a reaction force biased in the extension direction is prevented.

  As described above, the fall prevention devices of the first to fifth embodiments include the dampers 10, 110, 210, and 310, and are attached between the upper surface of the furniture F installed on the installation surface and the ceiling C. . The dampers 10, 110, 210, and 310 have a damping force generated during the contracting operation larger than the damping force generated during the extending operation, and a reaction force is urged in the extending direction. The dampers 10, 110, 210, 310 have piston rods 13, 313 and center rods 14, 114, 314. The piston rods 13 and 313 are formed with insertion holes 13A and 313A extending on the central axis. The center rods 14, 114, 314 are inserted into the insertion holes 13A, 313A of the piston rods 13, 313, and the positional relationship with the piston rods 13, 313 changes. The dampers 10, 110, 210, 310 are switched to one of a damping mode, a free mode, and a lock mode when the positional relationship between the piston rods 13, 313 and the center rods 14, 114, 314 is changed. In the damping mode, the dampers 10, 110, 210, and 310 are extendable, and a damping force that is greater than the damping force generated during the extension operation is generated during the contraction operation. In the free mode, the dampers 10, 110, 210, and 310 are extendable, and a damping force that is smaller than the damping force generated during the contracting operation in the damping mode is generated during the contracting operation. In the lock mode, the dampers 10, 110, 210, and 310 prevent or slow down the extension operation caused by the reaction force biased in the extension direction.

  This overturn prevention device changes the positional relationship between the piston rods 13 and 313 of the dampers 10, 110, 210, and 310 and the center rods 14, 114, and 314, and puts the dampers 10, 110, 210, and 310 in a damping mode. And attached between the upper surface of the furniture F and the ceiling C. Then, the dampers 10, 110, 210, and 310 provided in the overturn prevention device generate a damping force during the contraction operation that is larger than the damping force generated during the extension operation while the reaction force acts in the extension direction. For this reason, in this fall prevention device, when the furniture F tilts due to a shake such as an earthquake, the damping force generated when the dampers 10, 110, 210, 310 are contracted acts on the furniture F to suppress the tilt, and the furniture F Can be prevented from falling.

  In addition, this fall prevention device changes the positional relationship between the piston rods 13 and 313 of the dampers 10, 110, 210, and 310 and the center rods 14, 114, and 314, and puts the dampers 10, 110, 210, and 310 into the free mode. Then, the damping force generated during the contraction operation of the dampers 10, 110, 210, and 310 is smaller than the damping force generated during the contraction operation in the attenuation mode. That is, this fall prevention device can easily contract the dampers 10, 110, 210, 310 with a small force when the dampers 10, 110, 210, 310 are set to the free mode. Thus, this fall prevention device makes the dampers 10, 110, 210, 310 put into the free mode so that the damper 10, 110, 210, 310 can be easily contracted.

  In addition, the fall prevention device changes the positional relationship between the piston rods 13 and 313 of the dampers 10, 110, 210, and 310 and the center rods 14, 114, and 314, and puts the dampers 10, 110, 210, and 310 in the lock mode. Then, the extension operation of the dampers 10, 110, 210, 310 due to the reaction force biased in the extension direction is prevented or decelerated. Therefore, when the damper 10, 110, 210, 310 is contracted in order to attach or detach the fall prevention device between the upper surface of the furniture F and the ceiling C, the damper 10, 110, 210, 310 is used. Can be prevented from extending unexpectedly or vigorously. That is, when the fall prevention device is attached between the upper surface of the furniture F and the ceiling C, the dampers 10, 110, 210, 310 can be gradually extended, so that the fall prevention device can be attached in an appropriate state. it can. Further, when the fall prevention device attached between the upper surface of the furniture F and the ceiling C is removed, the contracted dampers 10, 110, 210, 310 do not extend unexpectedly or vigorously, so that the removal can be easily performed. it can.

  Therefore, the fall prevention devices of Embodiments 1 to 5 can be easily attached and detached.

  In the fall prevention devices of the first to fifth embodiments, the dampers 10, 110, 210, and 310 include the cylinder 11, the piston 15, the first flow path 21, 121, 321, the check valve 16, and the second flow path 22, 122. , 322. The cylinder 11 has a bottomed cylindrical shape. The piston 15 is slidably accommodated in the cylinder 11. The piston 15 partitions the inside of the cylinder 11 into a rod side chamber R1 and a bottom side chamber R2. Further, the piston 15 is connected to the tip portions of the piston rods 13 and 313. When the positional relationship between the piston rods 13 and 313 and the center rods 14, 114, and 314 is changed, the first flow paths 21, 121, and 321 are switched to a communication state or a blocking state. The first flow paths 21, 121, and 321 communicate the rod-side chamber R1 and the bottom-side chamber R2 in the communication state. In addition, the first flow paths 21, 121, and 321 block communication between the rod side chamber R1 and the bottom side chamber R2 in the blocked state. The check valve 16 is provided in the first flow path 21, 121, 321. The check valve 16 allows the hydraulic oil to flow from the rod side chamber R1 to the bottom side chamber R2, and prevents the reverse flow. When the positional relationship between the piston rods 13, 313 and the center rods 14, 114, 314 is changed, the second flow paths 22, 122, 322 are either in the first communication state, the second communication state, or the shut-off state. Switch. In the first communication state, the second flow paths 22, 122, and 322 communicate the rod side chamber R1 and the bottom side chamber R2 via the orifices 22C and 322C. The orifices 22C and 322C impart a resistance to the flow of hydraulic oil when the dampers 10, 110, 210, and 310 are contracted to generate a damping force. In addition, the second flow paths 22, 122, and 322 communicate the rod side chamber R1 and the bottom side chamber R2 via the communication path 22D and the fourth communication path 304 in the second communication state. The communication passage 22D and the fourth communication passage 304 have a larger flow area than the orifices 22C and 322C. The second flow paths 22, 122, and 322 have a larger flow rate of hydraulic fluid flowing in the second communication state than in the first communication state. Further, the second flow paths 22, 122, 322 block communication between the rod side chamber R1 and the bottom side chamber R2 in the blocked state. The dampers 10, 110, 210, 310 are switched to the attenuation mode when the first flow paths 21, 121, 321 are switched to the communication state and the second flow paths 22, 122, 322 are switched to the first communication state. The dampers 10, 110, 210, and 310 are switched to the free mode when the second flow paths 22, 122, and 322 are switched to the second communication state. The dampers 10, 110, 210, and 310 are switched to the lock mode when the first flow paths 21, 121, and 321 and the second flow paths 22, 122, and 322 are switched to the cutoff state.

  As described above, the fall prevention device changes the positional relationship between the piston rods 13 and 313 of the dampers 10, 110, 210, and 310 and the center rods 14, 114, and 314 to change the first flow paths 21, 121, and 321. By switching the state of the second flow paths 22, 122, 322, the dampers 10, 110, 210, 310 can be switched to any one of the attenuation mode, the free mode, and the lock mode.

  In the overturn prevention device of the third embodiment, the first flow path 121 of the damper 110 includes a first cut portion 21E. The first notch 21E changes the positional relationship between the piston rod 13 and the center rod 114, and in the process of switching the first flow path 121 from the communication state to the shut-off state, the flow rate of the hydraulic oil flowing through the first flow path 121 Reduce gradually. For this reason, this damper can adjust the flow volume of the hydraulic fluid which flows through the 1st flow path 121 by the 1st notch part 21E. The extension operation of the damper 110 due to the repulsive force biased in the extension direction of the damper 110 becomes slower as the flow rate of the hydraulic oil flowing through the first flow path 121 is decreased. For this reason, this fall prevention device adjusts the flow rate of the working oil flowing through the first flow path 121 by the first cut portion 21E, thereby increasing the extension speed due to the repulsive force biased in the extension direction of the damper 110. Since it can be adjusted, the damper 110 can be gradually extended and attached in an appropriate state between the upper surface of the furniture F and the ceiling C.

  In the overturn prevention device of the third embodiment, the second flow path 122 of the damper 110 includes a second cut portion 22E. The second notch 22E changes the positional relationship between the piston rod 13 and the center rod 114 to change the second flow path 122 from the second communication state to the shut-off state, and the hydraulic oil flowing through the second flow path 122 Gradually decrease the flow rate. For this reason, this damper 110 can adjust the flow volume of the hydraulic fluid which flows through the 2nd flow path 122 by the 2nd notch 22E. The extension operation of the damper 110 due to the repulsive force urged in the extension direction of the damper 110 becomes slower as the flow rate of the hydraulic oil flowing through the second flow path 122 is decreased in the state where the first flow path 121 is shut off. For this reason, this fall prevention device adjusts the flow rate of the working oil flowing through the second flow path 122 at the second cut portion 22E, thereby increasing the extension speed due to the repulsive force biased in the extension direction of the damper 110. Since it can be adjusted, the damper 110 can be gradually extended and attached in an appropriate state between the upper surface of the furniture F and the ceiling C.

  In the fall prevention devices of the first to fourth embodiments, the piston rod 13 and the center rods 14 and 114 change the positional relationship by relatively moving along the central axis. Therefore, an insertion hole 13A penetrating along the central axis is formed in the piston rod 13, inserted into the insertion hole 13A, and the protruding portions of the center rods 14, 114 protruding from the rear end portion of the piston rod 13 are operated. Thus, the positional relationship between the piston rod 13 and the center rods 14 and 114 can be easily changed by changing the protruding length.

  In the overturn prevention device of the fifth embodiment, the positional relationship between the piston rod 313 and the center rod 314 is changed by relatively rotating around the central axis. For this reason, an insertion hole 313A penetrating along the central axis is formed in the piston rod 313, inserted into the insertion hole 313A, and the protruding portion of the center rod 314 protruding from the rear end portion of the piston rod 313 is rotated. Thus, the positional relationship between the piston rod 313 and the center rod 314 can be easily changed.

  In the overturn prevention devices of the first to fourth embodiments, a cam 53 and a first lever 51 are provided. The cam 53 is rotatably supported on the rear end side of the piston rod 13. When the cam 53 rotates, the center rods 14 and 114 move along the central axis. The first lever 51 is connected to the cam 53. In this fall prevention device, as the first lever 51 moves around the rotation shaft 31 and approaches the piston rod 13, the cam 53 rotates and the positional relationship between the piston rod 13 and the center rod 14 changes. The dampers 10, 110, and 210 are switched in the order of the attenuation mode, the lock mode, and the free mode. Therefore, when the first lever 51 is brought close to the piston rod 13 so as to grasp the first lever 51 and the piston rod 13, the dampers 10, 110, and 210 are in the free mode, and the first lever 51 and the piston rod 13 are grasped. The dampers 10, 110, and 210 can be easily contracted while remaining.

  In the overturn prevention device of the fourth embodiment, the damper 210 has a pin member 71. The insertion hole 13A passes through the piston rod 13 along the central axis. The center rod 14 extends along the central axis with the second flow path 22 opening at the distal end surface. In a state where the damper 210 is most contracted, the pin member 71 is inserted from the bottom side chamber R2 into the insertion hole 13A opened at the distal end surface of the piston rod 13 to block the insertion hole 13A and block the second flow path 22. For this reason, this fall prevention device prevents the extension operation due to the reaction force biased in the extension direction with the first flow path 21 and the second flow path 22 in the closed state in the state where the damper 210 is most contracted. The most contracted state can be maintained. Therefore, this fall prevention device can hold the damper 210 in the most contracted state, and can pack or carry it.

The present invention is not limited to the first to fifth embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the first lever and the second lever are provided in the first to fourth embodiments, the second lever may not be provided. In this case, a grip portion that can be gripped when the first lever is moved closer to the piston rod instead of the second lever may be provided separately.
(2) In the first to fourth embodiments, as the first lever and the second lever are moved closer to the piston rod, the damper is switched in the order of the damping mode, the lock mode, and the free mode. The mode may be switched.
(3) In the fourth embodiment, the pin member is provided on the free piston, but the pin member may be provided on the bottom of the cylinder.
(4) In Embodiment 3, the first flow path conversion unit and the second flow path changing unit are provided, but only one of them may be provided.
(5) In the first to fifth embodiments, the hydraulic oil is filled in the cylinder, but another liquid may be filled instead of the hydraulic oil.
(6) In Embodiments 1 to 5, the compressed gas is sealed in the cylinder, but a compression coil spring may be housed in the bottom chamber instead of the compressed gas.
(7) The cam shape of the operation portion of the third and fourth embodiments may be the cam shape of the second embodiment.

  10, 110, 210, 310 ... damper, 11 ... cylinder, 13,313 ... piston rod, 13A ... insertion hole, 14, 114, 314 ... center rod, 15 ... piston, 16 ... check valve, 21, 121, 321 ... 1st flow path, 21E ... 1st notch part (1st flow volume change part), 22, 122,322 ... 2nd flow path, 22C, 322C ... Orifice, 22E ... 2nd notch part (2nd flow rate change) Part), 51 ... first lever (lever), 53 ... cam, 71 ... pin member, C ... ceiling, F ... furniture (article), R1 ... rod side chamber, R2 ... bottom side chamber

Claims (8)

A damping force generated during the contraction operation is greater than the damping force generated during the extension operation, and the damper is provided with a reaction force urged in the extension direction, and is attached between the article installed on the installation surface and the ceiling. A fall prevention device,
The damper is
A piston rod formed with an insertion hole extending on the central axis;
A center rod that is inserted into the insertion hole of the piston rod and changes a positional relationship with the piston rod;
Have
When the positional relationship between the piston rod and the center rod is changed,
A damping mode in which the damper is extendable and a damping force that is greater than the damping force that is generated during the extension operation is generated during the contraction operation;
A free mode in which the damper is telescopic and a damping force smaller than the damping force generated during the contracting operation in the damping mode is generated during the contracting operation;
Or a lock mode that prevents or decelerates the extension operation of the damper due to the reaction force biased in the extension direction;
A fall prevention device characterized by switching to any of the above. The damper is
A bottomed cylindrical cylinder;
A piston that is slidably accommodated in the cylinder, divides the cylinder into a rod side chamber and a bottom side chamber, and a piston to which a tip portion of the piston rod is coupled;
When the positional relationship between the piston rod and the center rod is changed, the state is switched to a communication state in which the rod side chamber and the bottom side chamber communicate with each other, or a communication state in which the communication between the rod side chamber and the bottom side chamber is blocked. One flow path;
A check valve provided in the first flow path, allowing a flow of the working liquid from the rod side chamber to the bottom side chamber, and preventing the reverse flow;
When the positional relationship between the piston rod and the center rod is changed, the rod side chamber and the bottom side chamber are communicated with each other via an orifice that gives resistance to the flow of the working liquid and generates a damping force during the contraction operation. A first communication state, a second communication state in which the rod-side chamber and the bottom-side chamber communicate with each other through a communication passage having a flow area larger than that of the orifice, and the flow rate of the working fluid flowing is larger than that in the first communication state; Or a second flow path that switches to one of a blocked state in which communication between the rod side chamber and the bottom side chamber is blocked;
Have
When the first flow path is switched to the communication state and the second flow path is switched to the first communication state, the mode is switched to the attenuation mode, and when the second flow path is switched to the second communication state, the free mode is switched. 2. The overturn prevention device according to claim 1, wherein when the first flow path and the second flow path are switched to the shut-off state, the lock mode is switched.   The first flow path gradually decreases the flow rate of the working liquid flowing through the first flow path in the process of changing the positional relationship between the piston rod and the center rod to switch from the communication state to the shut-off state. The overturn prevention device according to claim 2, further comprising a first flow rate converter.   The second flow path gradually changes the flow rate of the working liquid flowing through the second flow path in the process of changing the positional relationship between the piston rod and the center rod to switch from the second communication state to the shut-off state. The fall prevention device according to claim 2 or 3, further comprising a second flow rate changing unit that reduces the flow rate.   The fall prevention device according to any one of claims 1 to 4, wherein the piston rod and the center rod change a positional relationship by relatively moving along a central axis.   5. The overturn prevention device according to claim 1, wherein the piston rod and the center rod change a positional relationship by relatively rotating around a central axis. 6. A cam that is rotatably supported by a rotation shaft provided on the rear end side of the piston rod, and the center rod moves along a central axis when rotated;
Connected to the cam. A lever that moves around the pivot axis;
With
As the lever moves around the pivot axis and approaches the piston rod, the cam pivots and the positional relationship between the piston rod and the center rod changes, and the damper is in the damping mode, 6. The overturn prevention device according to claim 5, wherein the switching is performed in the order of a lock mode and the free mode. The piston rod has the insertion hole extending along a central axis,
The center rod is a damper in which the second flow path opens at the front end surface and extends along the central axis,
In the most contracted state, it has a pin member that is inserted from the bottom side chamber side into the insertion hole that opens to the tip surface of the piston rod, seals the insertion hole, and blocks the second flow path. The fall prevention device according to any one of claims 2 to 4.

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