JP2773852B2 - Fall prevention mechanism of telescopic strut - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for preventing a telescopic strut from collapsing so that the strut is stretched when used and its height is adjusted, and when not in use, the strut is shrunk to facilitate transportation.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 11, a telescopic strut of this type has at least a diameter gradually reduced with respect to the base post 100 inside a base post 100 fixed vertically to a pedestal (not shown). One middle pillar, in this example, two middle pillars 101 and 102 are loosely fitted in a vertically slidable manner, and pulleys 103, 104 and 105 are attached to appropriate positions on the peripheral walls of the base pillar 100 and the middle pillar 101, respectively. Wire rope 106 with one end fixed to a small-diameter middle tube post 102
Is wound around the pulleys 103 to 105, and the other end of the wire rope 106 is fixed to a hoist 107.
7 to raise the middle pillars 101 and 102 by the hoisting operation, so that the height of any equipment installed on the upper end of the middle pillar 102, such as lighting lamps and speakers for road works, can be adjusted appropriately. I have. According to the telescopic strut having such a configuration, when the wire rope 106 is cut, all of the middle pillars 101 and 102 fall, and there is a possibility that equipment such as a lighting lamp and a speaker may be damaged, However, there is a drawback that workers and passers-by, which are present in Japan, are extremely dangerous.

To solve the above-mentioned drawbacks, Japanese Patent Application Laid-Open No.
A fall prevention mechanism disclosed in Japanese Patent Application Laid-Open No. 3-189578 is conventionally known. This will be described with reference to FIGS. 9 and 10. Pulleys 111 provided at appropriate positions of an arbitrary column 110 are described.
The shaft hole 113 into which the rotating shaft 112 is loosely fitted is formed as a long hole in the vertical direction, and the movable pulley can be separately locked together with the rotating shaft 112 at the ascending position and the descending position. Is provided with a locking claw 114 which protrudes toward the peripheral wall of the tube post 110 at the downward locking position, and is rotatably supported so as to retreat toward the inside of the tube post 110 at the upward locking position, and the tube post 110 is loosely fitted. An engaging portion 116 with which the locking claw 114 is engaged at the projecting position is formed at a plurality of appropriate places on the peripheral wall of the tube post 115, and when the pulling force is lost due to a breakage of the wire rope 106, etc. As shown in FIG. 10, the moving pulley 111 is locked at the lowered position, and the locking claw 114 is engaged with the
The structure prevents the 110 from falling.

[0004]

By the way, in the telescopic strut, the pulley 10 shown in FIG.
A wire rope 106 is doubled or tripled between 3 and 104, and even if the wire rope 106 is cut in the middle, there is a case where a resistance is generated at the crossed portion and the tensile force is maintained. Therefore, according to the conventional fall prevention mechanism, even if the wire rope 106 breaks, the moving pulley 111 does not descend,
There is a danger that the tube column 110 will fall down as the 114 remains retracted, leaving room for improvement in this regard. To solve such a problem, a guide shaft (fixed shaft) 118 for guiding a guide hole 117 formed in the locking claw 114 and a rotating shaft 11
A spring 120 for urging the moving pulley 111 downward is provided between the moving pulley 111 and the moving pulley 111 to be forcibly lowered when the wire rope 106 is cut so that the locking claw 114 is reliably projected. Is also conceivable.

However, in the conventional fall prevention mechanism, the rotation fulcrum 119 of the locking claw 114 is provided so as to be rotatable with respect to the rotating shaft 112 of the moving pulley 111.
Since it is configured to move up and down integrally with 111, the locking claw 114
Is inserted into the engaging portion 116, the claw 114 is
The spring 120 loses the force colliding with the bottom wall 116a, and the locking claw 114 rises together with the moving pulley 111 and retreats inward again, so that the fall of the tube post 110 cannot be stopped. In order to prevent this, the stronger the urging force of the spring 120, the better. However, if it is too strong, the locking claw 114 will not retreat when the tube post 110 is raised normally, and therefore the pulling force of the wire rope 106 Thus, only the strength of the spring that allows the locking claw 114 to be retracted can be selected, and it is difficult to solve the above problem under this condition.

[0006] The present invention has been made in view of the above-described conventional circumstances, and an object of the present invention is to urge the above-described movable pulley together with the rotating shaft in the direction of the downwardly locked position so that the wire rope can be moved. Make sure that the locking claw protrudes when it breaks, and that the urging force is such that the locking claw is securely retracted by the pulling force of the wire rope. An object of the present invention is to provide a fall prevention mechanism which does not have a possibility that the locking claw will retreat again even when a force for pushing back the locking claw is applied.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned object, according to the present invention, there is provided at least one middle pipe column having a diameter smaller than that of the base column inside a base column fixed vertically to a pedestal. It is loosely fitted up and down slidably, and a pulley is provided at an appropriate position on the base tube column and any middle tube column, and a wire rope having one end fixed to the minimum diameter middle tube column is wrapped around each pulley, and the wire rope is provided. A drop prevention mechanism of a telescopic strut which raises each middle tube post by winding up the other end, and an arbitrary pulley provided in the above-mentioned tube post is moved up and down through a shaft hole in which a rotating shaft is loosely fitted. A movable pulley that can be separately locked at an ascending position and a descending position together with a rotating shaft as a long hole in the direction, and rotates around a fixed shaft provided at an appropriate position in the vicinity of the movable pulley as a fulcrum. A locking claw is provided, and this locking claw has a long hole shape that is long in the vertical direction. At a slight angle to the left or right, the rotating shaft of the moving pulley is loosely fitted, and the locking claw is projected toward the peripheral wall of the tube post at its lowered locking position. A guide hole for retreating inward of the column is provided, and a spring for urging the moving pulley to the downward locking position is provided, and the moving pulley is securely raised by the pulling force of the wire rope. It is characterized in that an engagement portion is provided at an appropriate position of the tube post which loosely fits into the tube post having the moving pulley, and which engages with a locking claw projecting in the peripheral wall direction. And

[0008]

According to the above construction, when the pulling force is acting on the wire rope, the movable pulley is securely locked at the raised position together with the rotating shaft against the urging force of the spring.
In this state, the locking claw is guided by the guide hole provided therein and is retracted inward of the tube post. This state is maintained as long as the pulling force of the wire rope is not lost, and has no effect on the rise and fall of the pipe column (see FIG. 4).
In this state, if the pulling force is lost due to the wire rope being cut or the like, the movable pulley is securely locked at the lowered position together with the rotating shaft by the urging force of the spring, and the locking claw is guided by the guide hole. Then, it rotates around the fixed shaft and protrudes in the direction of the peripheral wall of the tube post, and engages with the engaging portion to prevent the tube post from falling (see FIG. 5). At this time, the movable pulley is biased toward the downward locking position by the spring, so that when the wire rope is cut, the rotating shaft is forcibly lowered together with the movable pulley to reliably project the locking claw. Become like In addition, even if the locking claw collides against the bottom wall of the engaging portion and the like, and a force for pushing up the locking claw is applied, the fixed shaft functions as a stopper to prevent the locking claw from retreating. Even if the pawl collides against the inner wall of the tube post and a force that pushes the locking claw back into the tube post acts, the rotating shaft in the guide hole functions as a stopper to prevent the locking claw from retreating. While the biasing force of the spring is set to such a degree that the locking claw is reliably retracted by the pulling force of the wire rope, it is possible to reliably prevent the locking claw from retreating into the tube post.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fall prevention mechanism according to the present invention will be described below with reference to FIGS. 1 and 2 are longitudinal side views of an example of a telescopic strut A to which the fall prevention mechanism of the present invention is installed, and FIG. 8 is a side view of a movable lighting device showing an example of a usage form of the telescopic strut A. In the drawing, reference numeral 1 denotes a first column as a base column fixed vertically to the mobile trolley B, and a first notch 2 is formed on the peripheral wall along the vertical direction. 3
Is a winch fixed to the lower end of the first column 1, and 4 is a first pulley (fixed pulley) fixedly supported on the upper end of the first column 1 so as to be rotatable around a rotation shaft 4a. The winch 3 may be fixed to another place, for example, to the mobile trolley B, without being provided on the first column 1.

Reference numeral 5 denotes a second pipe pillar as a middle pipe pillar which is loosely fitted in the first pipe pillar 1 so as to be vertically slidable. A second notch 6 is formed in the peripheral wall along the vertical direction. A second upper pulley (fixed pulley) is provided at the upper end of the inner wall of the second pipe post 5 across the two notches 6.
7 is fixedly supported so as to be rotatable about a rotation shaft 7a, and at the lower end thereof, a second lower pulley (moving pulley) 8 is rotatable about the rotation shaft 8a and the rotation shaft 8a is slightly moved together with the pulley 8. Supports vertical movement and locking. Reference numeral 9 denotes a third pipe pillar as a middle pipe pillar which is loosely fitted into the second pipe pillar 5 so as to be vertically slidable. The third notch 10 is formed on the peripheral wall along the vertical direction. Notch
A third upper pulley (moving pulley) 11 is rotatable around a rotation axis 11a at the upper end of the inner wall of the third tube post 9 over the rotation axis 10a. The third lower pulley (moving pulley) 12 is a rotating shaft at the lower end.
The rotary shaft 12a is rotatable about the center 12a, and the rotary shaft 12a is supported together with the pulley 12 so that the shaft 12a can be slightly moved up and down and locked. The second upper pulley 7 and the lower pulley 8 are provided at positions through which the inside of the third notch 10 is inserted.

Reference numeral 13 denotes a fourth tube column as a middle tube column which is loosely fitted in the third tube column 9 so as to be slidable up and down. A fourth notch 14 is formed on the peripheral wall along the vertical direction. And the third upper pulley
11, the lower pulley 12 is provided at a position to be inserted through the fourth notch 14. Providing the respective pulleys 7, 8, 11, and 12 at positions to be inserted through the notches 10 and 14 in this manner makes the moving space of each pulley outside the column like the conventional telescopic strut shown in FIG. It is possible to reduce the inner diameter of each of the pipe columns 1, 5, 9, 13 as compared with the configuration to secure the weight, thereby achieving weight reduction. Therefore, the lifting operation can be performed with an extremely light operating force and the working efficiency is improved. In addition to the advantages that the size is reduced and the weight is reduced, the movement becomes very easy. It is extremely useful in that

A mercury light C for lighting in road works is attached to the upper end of the fourth tubular column 13. Reference numeral 15 denotes a wire rope, one end of which is fixed to a fourth pillar 13 which is a medium diameter pillar having a minimum diameter, and is sequentially wound around each of the pulleys 11, 12, 7, 8, and 4; The telescopic column is extended to a predetermined height by raising the second column 5, the third column 9, and the fourth column 13 by the operation of hoisting the winch 3, thereby extending the upper end of the fourth column 13. The height position of the mounted light C is arbitrarily adjusted.

In this embodiment, as described above, the second lower pulley 8, the third upper pulley 11, and the third lower pulley 12 of the telescopic strut A having the above-described structure are rotated by their rotating shafts 8a, 11a, 12a. In addition to the movable pulleys supported so as to be able to be locked up and down slightly, a locking claw 23 that rotates in conjunction with the up and down movements of the respective pulleys 8, 11, and 12 is provided. 2nd pipe column 5, 4th
At an appropriate position on the peripheral wall of the tube 13, an engaging portion 26 with which each of the locking claws 23 is engaged at the projecting position is provided, so that the second tube 5, the third tube 9, and the fourth tube 13 fall. Is provided to prevent the telescopic strut A from falling as a whole, and its structure will be described in detail below with reference to FIGS. FIGS. 3 to 6 show a fall prevention mechanism of the second pipe column 5, and the fall prevention mechanism of the third pipe column 9 has the same configuration, and thus the description is omitted. FIG. 7 shows a mechanism for preventing the fourth column 13 from dropping. In this case, too, the projecting direction of the locking claw 23 and the location where the engaging portion 26 is formed are prevented from falling by the second and third columns 5, 9. Since the configuration is the same except that the mechanism is reversed, the description is omitted.

In FIGS. 3 to 6, reference numerals 20, 20 denote second column 5
Are fixed over the second notch 6 with a pair of bearings fixed to the lower part of the bearing. 21 and 21 are the bearings 20 and 20, respectively.
The rotation shaft 8a of the second lower pulley 8 is loosely fitted in the shaft holes 21 and 21 by a pair of shaft holes formed in a vertically long slot shape, whereby the second lower pulley 8 rotates. A movable pulley that can be locked at the ascending position and the descending position together with the shaft 8a. Reference numeral 22 denotes a pin fixed below the bearing 20, and reference numeral 23 denotes a locking claw provided at a position adjacent to the second lower pulley 8.

The locking claw 23 is a fixed shaft provided at a position near the shaft hole 21 in the bearing 20, in this embodiment at a position obliquely above the shaft hole 21.
24 rotatably supported. The locking claw 23 has a long hole shape in the vertical direction and is slightly inclined diagonally to the left, and the rotating shaft 8a is loosely fitted to the locking claw 23 at the lowered locking position of the rotating shaft 8a. Is rotated in the direction of the peripheral wall of the second tube post 5 so that its tip claw 23a projects from the second notch 6, and the locking claw 23 of the second tube post 5 is raised at the position where the rotating shaft 8a is raised. A guide hole 25 for retreating inward is provided.

Reference numeral 26 denotes an engaging portion, which is a protruding piece that protrudes in a cantilever shape at a side edge portion of the first notch 2 of the first column 1 which is a column into which the second column 5 is loosely fitted. 27 are provided at appropriate intervals so as to form a plurality of steps and engage with the tip claw portions 23a of the locking claws protruding from the second cutouts 6 so as to prevent the second column 5 from dropping. Has become. The engaging portion 26 is not limited to the one formed as described above, but may be any other position as long as it engages with the tip claw portion 23a of the locking claw protruding from the second notch 6. For example, the first cutting portion may be used. It may be formed by an opening formed in a multi-stage shape on the side of the notch 2. Reference numeral 28 denotes a spring which is stretched between the rotation shaft 8a and the pin 22 and urges the second lower pulley 8 together with the rotation shaft 8a in the downward locking position. The urging force is the pulling force of the wire rope 15. So that the lower pulley 8 together with the rotary shaft 8a is securely locked at the raised position.

That is, while the pulling force is acting on the wire rope 15, as shown in FIGS.
Since it has been lifted above the shaft hole 21 with 8a, that is, to the raised locking position, the locking claw 23 is also retracted. This state is maintained as long as the pulling force of the wire rope 15 is not lost, and the rise and fall of the second pipe column 5 are not affected at all.

However, when the wire rope 15 is cut and the pulling force is no longer applied, the second lower pulley 8 drops due to its own weight and the urging force of the spring 28 as shown in FIGS.
Together with the shaft hole 21, that is, to the lower locking position,
As a result, the guide hole 25 moves along the rotating shaft 8a, so that the locking claw 23 rotates in the direction of the peripheral wall of the second tube post 5, and the tip claw portion 23a protrudes from the second notch 6, and The engagement of any one of the engaging portions 26 stops the drop of the second tube post 5. At this time, since the movable pulley 8 is urged toward the lower locking position by the spring 28, when the wire rope 15 is cut, the rotating shaft 8a is forcibly lowered together with the movable pulley 8 and the locking claw is locked. The tip claw portion 23a of the second protrusion surely projects. Further, even if the force of pushing up the locking claw 23 is exerted due to the tip claw portion 23a colliding with the engagement portion bottom wall 26a or the like, the fixed shaft 24
Functions as a stopper to prevent the locking claw 23 from retreating,
Further, even if the tip claw portion 23a collides against the inner wall of the first tube post 1 and a force for pushing the locking claw 23 inward is exerted, the rotating shaft 8a in the guide hole 25 functions as a stopper. Locking claw
23 is prevented from retreating, so that the urging force of the spring 28 is set to such a degree that the locking claw 23 is reliably retracted by the pulling force of the wire rope 15, while ensuring that the locking claw 23 may be retracted inward. Can be prevented.

This is the same in a fall prevention mechanism of the third column 9 not shown in the drawing.
The plurality of engaging portions 26 engaging with the notches 23 are formed by the notches 10
It is provided at a position where it can be engaged with the tip claw portion 23a of the locking claw protruding from the second notch 6, that is, on the side of the second notch 6. Further, the same applies to the fall prevention mechanism of the fourth column 13 shown in FIG. 7, and the plurality of engaging portions 26 that engage with the locking claws 23 of the third upper pulley 11 On the peripheral wall facing the notch 14, it is provided at a position where it can be engaged with the tip claw portion 23 a of the locking claw 23 rotated in the peripheral wall direction.

As shown in FIG. 2, the telescopic strut equipped with the fall prevention mechanism of this embodiment having the above structure
Is wound up, the wire rope 15 is wound up, and first, the fourth pipe column 13 rises. At this time, it rises through the pulleys 11 and 12 by the fourth notch 14. Then, the third pipe column 9,
The second pipe column 5 is similarly sequentially pulled up, and can be raised to the state shown in FIG. When the wire rope 15 breaks, the second state is changed from the state shown in FIGS. 3 and 4 to the second state as shown in FIG.
The lower pulley 8 is lowered by its own weight and the urging force of the spring 28,
Is turned in the direction of the notch 6 and the tip claw 23a engages with the engaging portion 26, so that the drop of the second tube post 5 is stopped. Although not shown, the third tube 9 and the fourth tube 13 shown in FIG. 7 have the same effect, and the second tube 5, the third tube 9, and the fourth tube 13 are dropped as a whole. It can be minimized to prevent the illumination lamp C installed at the upper end of the fourth pipe column 13 from being damaged, and to ensure the safety of workers and passers nearby.

The structure of the telescopic strut is not limited to the one shown in the drawing, and the number of middle tube posts and the number and position of pulleys can be arbitrarily changed. It is needless to say that the fall prevention mechanism of the present invention is constituted by appropriately providing a spring, an engagement portion and the like at appropriate places. The usage form of the telescopic strut is not limited to the one shown in FIG. 8, and a speaker or other equipment may be installed in place of the illumination light C, or a pedestal for fixing the first pillar 1 as a base pillar. It is optional to change within a well-known range in place of the illustrated moving cart B.

[0022]

As described above, according to the present invention, when a pulling force is applied to the wire rope, the movable pulley is securely locked together with its rotating shaft at the raised position against the urging force of the spring. In this state, the locking claw is at a position retracted inward of the tube post, and has no effect on the ascending or descending of the tube post. Further, when the pulling force is lost due to the wire rope being cut or the like, the locking claw is reliably projected by the urging force of the spring, and is engaged with the engaging portion to prevent the column from dropping. Moreover, in this state, even if the drop of the tube post is urged for some reason and the force for retracting the locking claw is exerted, the fixed shaft supporting the locking claw and the guide hole of the locking claw play loosely. Since the rotating shaft to be fitted functions as a stopper, the engaging state of the engaging claw and the engaging portion can be ensured while the urging force of the spring is set to such a degree that the engaging claw is securely retracted by the pulling force of the wire rope. Can be maintained. Therefore, even if the wire rope is cut, the impact on any equipment installed at the upper end of the tube column, for example, a lighting lamp or a speaker, is small, and the damage to these equipment can be prevented and the equipment is located nearby. The reliability of the product can be improved by making the advantages of the conventional fall prevention mechanism that can ensure the safety of workers and passers-by more effective, and without affecting the normal operation of the telescopic struts at all An extremely excellent effect that work can be performed efficiently is achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an example of a telescopic support column equipped with a fall prevention mechanism according to the present invention.

FIG. 2 is a longitudinal sectional side view of a state where a telescopic support shown in FIG. 1 is extended.

FIG. 3 is an explanatory view showing an example of a fall prevention mechanism according to the present invention.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a vertical sectional side view showing an operation state of the fall prevention mechanism shown in FIG. 4;

FIG. 6 is a sectional view taken along lines (X)-(X) in FIG. 5;

FIG. 7 is an enlarged sectional view showing another example of the fall prevention mechanism according to the present invention.

FIG. 8 is a side view showing an example of use of a telescopic strut equipped with a fall prevention mechanism according to the present invention.

FIG. 9 is a vertical sectional side view showing a conventional fall prevention mechanism.

10 is a vertical sectional side view showing an operation state of the fall prevention mechanism shown in FIG. 9;

FIG. 11 is a longitudinal side view showing a conventional general telescopic strut.

[Explanation of symbols]

A: Telescopic column B: Moving carriage as pedestal 1: First column as base column 5, 9, 13: Second, third, and fourth column as middle column 8, 11, 12: Moving Second lower, third upper and third lower pulleys as pulleys 15: Wire rope 21: Shaft hole 23: Locking claw 24: Fixed shaft 25: Guide hole 26: Engagement part 28: Spring

Claims (1)

(57) [Claims] 1. Inside a base pillar fixed vertically to a pedestal,
At least one middle tube column having a smaller diameter is sequentially fitted to the base tube column so as to be slidable up and down, and a pulley is provided at an appropriate position on the base tube column and any middle tube column. A wire rope having one end fixed to each pulley, and a fall prevention mechanism of a telescopic strut that raises each middle tube post by winding up the other end of the wire rope, provided on the tube post. Any of the pulleys has a shaft hole in which the rotating shaft is loosely fitted, and is formed as a long hole in the vertical direction. The pulley can be separately locked together with the rotating shaft at the ascending position and the descending position. In the vicinity, a locking claw that rotates around a fixed shaft provided at an appropriate place is provided as a fulcrum, and the locking claw is a long hole in the vertical direction and is slightly inclined diagonally left or right, The rotating shaft of the movable pulley is loosely fitted and the locking claw is A guide hole is provided for projecting in the direction of the peripheral wall to retreat the locking claw toward the inside of the tube post at the raised locking position, and further provided with a spring for urging the moving pulley to the lowered locking position. The urging force is such that the moving pulley is securely locked at the ascending position by the pulling force of the wire rope,
A fall prevention mechanism for a telescopic strut, wherein an engaging portion is provided at an appropriate position of the tube post into which the tube post having the movable pulley is loosely fitted to engage with a locking claw protruding in a peripheral wall direction. .