Locking tool for fall prevention net

Abstract

To provide a locking tool for a fall prevention net which is easy to mount and excellent in holding force of the fall prevention net.SOLUTION: A locking tool 1 of a fall prevention net includes a main body 9 loosely fitted to a column material 5 from a horizontal direction, and a hook part 11 provided on a main body 9 and hooking a fall prevention net 7. The main body 9 has a pair of holding parts 13A, 13B respectively arranged on the right and left of the column material 5, and a connecting part 17 connecting the pair of holding parts 13A, 13B. When the main body is rotated around a horizontal axis from a state of being loosely fitted to the column material 5, the pair of holding parts 13A, 13B are brought into pressure contact with the column material 5 to be mounted, and the hook part 11 is provided on at least one of the pair of holding parts 13A,13B.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a locking device for a fall prevention net used at an assembly site of a hierarchical building structure body or the like. In particular, the present invention relates to a locking device for a fall prevention net having a new structure that significantly improves workability and also has excellent holding power of the fall prevention net.

Background Art

[0002] When working at a high place such as an assembly site of a hierarchical building structure body, the use of a fall prevention net is obligatory by laws such as the Building Standards Law (for example, Article 136-5 of the Ordinance for the Enforcement of the Building Standards Law, "Protection against falling objects" and "Safety standards regarding the structure of safety nets" defined by the General Incorporated Association of Temporary Construction Industries). When attaching this fall prevention net to a building structure body, it is common to attach a hanging tool to the building structure body and hang the fall prevention net by hooking a reinforcing rope or the like at the periphery of the fall prevention net on a hook provided on this hanging tool (see Patent Documents 1, 2, etc.).

[0003] The hanging tool described in Patent Document 1 forms a saddle-type support portion in which the middle portion of a round bar-shaped member is bent and hooked from above onto a beam member of a building, and both ends of the round bar-shaped member are bent to hang the fall prevention net. Further, the hanging tool described in Patent Document 2 has an attachment portion in which a plate-shaped member is bent and fixed to a building structure body with screws, and a hook portion for hanging the fall prevention net. This hanging tool is characterized in that the hook portion is formed wide and has a depth, and the hook portion is provided at an angle inclined backward to prevent the fall prevention net from coming off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the suspension tool described in Patent Document 1 has a structure in which the support part is hooked and attached from above to a beam material that is a building structure body, there is a risk that the suspension tool may fall off due to vibration or the like. In addition, since the hook part is formed simply by bending both ends of a round bar-shaped member into a loop shape, it is weak in strength, and there is also a risk that the hook part may deform or break when a large load is applied. Since the suspension tool described in Patent Document 2 has a structure in which the suspension tool is attached to the building structure body by screwing, when a large load is applied to the hook part, there is a risk that the screw may break or fall out, causing the fall prevention net to fall together with the suspension tool. Further, since the hook part is formed simply by bending a plate material, even if the shape is devised as described above, there is a limit to its strength, and there is also a problem in the structural state that it cannot withstand a large load.

[0006] In view of the above circumstances, an object of the present invention is to provide a locking tool for a fall prevention net that is easy to attach and has excellent holding power for the fall prevention net.

Means for Solving the Problems

[0007] The locking tool for a fall prevention net of the present invention that solves the above object includes a main body that is loosely fitted horizontally to a column member of a building structure body, and a hook part provided on the main body for hooking the fall prevention net. The main body has a pair of clamping parts respectively arranged on the left and right of the column member, and a connecting part that connects the pair of clamping parts. When it rotates around a horizontal axis from a state of being loosely fitted to the column member, the pair of clamping parts are respectively attached in contact with the column member. The hook part is provided on at least one of the pair of clamping parts.

[0008] Here, the hook portion may be provided on each of the pair of clamping portions, and the locking member may have a bilaterally symmetric shape. Further, the main body may have a U-shaped cross section in plan view. The distance between the pair of clamping portions can be easily fitted to the column member from the horizontal direction, and when the pair of clamping portions rotate about a horizontal axis from a state of being loosely fitted to the column member, the pair of clamping portions come into contact with the column member respectively. It is set to be slightly larger than the thickness of the column member. Here, when the main body is loosely fitted to the column member, the column member may be inserted between the pair of clamping portions with the main body in a horizontal posture. Further, the column member may be inserted between the pair of clamping portions with the main body in a slightly tilted posture (slightly rotated about a horizontal axis).

[0009] The locking member of the fall prevention net of the present invention is loosely fitted to the column member from the horizontal direction, and by rotating about a horizontal axis, the pair of clamping portions are respectively brought into contact with the column member and attached. For this reason, the attachment to the column member becomes extremely easy. For example, from a state of being loosely fitted to the column member, the main body is rotated so that the clamping portion provided with the hook portion for hooking the fall prevention net is downward, and each of the pair of clamping portions may be attached by contacting the column member. Further, when a load is applied to the hook portion, the main body tries to rotate further from a state where the pair of clamping portions are in contact with the column member, and the pair of clamping portions bite into the column member respectively. Therefore, the column member is clamped and held by the pair of clamping portions with a strong force. Thereby, it becomes possible to hold the fall prevention net even when a large force is applied to the hook portion.

[0010] In the locking member of the fall prevention net of the present invention, each of the pair of clamping portions has a rectangular frame shape, The connecting portion constitutes one side of the pair of clamping portions and connects the two, The hook portion is preferably raised upward from one outer side of each of the pair of clamping portions.

[0011] Here, the hook portion may be inclined upward diagonally so as to face inward.

[0012] In this way, by configuring the clamping portion that clamps the column material in a rectangular frame shape, the structure becomes stronger, and further improvement in strength can be achieved. Also, since the hook portion is raised upward from one outer side of each of the pair of clamping portions, the risk of the fall prevention net hooked on the hook portion falling off from the hook portion is also reduced.

[0013] Also, in the fixture for the fall prevention net of the present invention, the connecting portion is provided with a screwing portion at an intermediate position in the left - right direction, The screwing portion may be provided with mounting holes for screwing.

[0014] Here, the screwing portion may be plate - shaped, and the mounting hole may be one or a plurality.

[0015] By adopting this aspect, the mounting state with respect to the column material can be stabilized, and displacement and dropping can be more reliably prevented. Here, the load applied to the hook portion is mainly applied to the pair of clamping portions, and the load applied to the screw inserted into the mounting hole is kept small. Therefore, the risk of the screw breaking or falling out is also small.

[0016] Furthermore, in the fixture for the fall prevention net of the present invention, the main body may be formed by deformed reinforcing bars having unevenness on the surface.

[0017] By doing so, the unevenness on the surface of the deformed reinforcing bar acts so as to bite into the column material. Therefore, for example, slipping downward of the fixture is also prevented.

Effects of the Invention

[0018] According to the present invention, it is possible to provide a fixture for a fall prevention net that is easy to install and has excellent holding power for the fall prevention net.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of a fastener for a fall prevention net in the present invention will be described with reference to the drawings. Hereinafter, the fastener for the fall prevention net of the present invention may be simply referred to as a fastener for explanation.

[0021] First, the structure of the fastener of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is an exploded perspective view of a fastener 1 showing an embodiment of the present invention. FIG. 2 is a front view of the fastener 1 shown in FIG. 1, and FIG. 3 is a plan view of the fastener 1 shown in FIG. 1. In this specification, in FIG. 1, the direction connecting the upper left diagonal and the lower right diagonal is defined as the left - right direction X, and the direction connecting the lower left diagonal and the upper right diagonal is defined as the front - rear direction Y for explanation.

[0022] The locking device 1 of the present invention is a locking member for suspending a fall prevention net 7, which is attached to a wooden column member 5 in a building structure body 3. In this embodiment, for example, a mode of attachment to a column member 5 made of a 3.5-inch square (10.5 cm square) square bar will be described as an example. Specifically, as shown in FIGS. 1 to 3, the locking device 1 includes a main body 9 that is loosely fitted to the column member 5 from the front Y1 to the rear Y2 in the horizontal direction H, and a hook portion 11 provided on the main body 9. The main body 9 has a pair of clamping portions 13A and 13B respectively arranged on the left and right sides of the column member 5, and a connecting portion 17 that connects the pair of clamping portions 13A and 13B.

[0023] In this embodiment, each of the pair of clamping portions 13A and 13B employs a rectangular frame-shaped main body 9. As shown in FIG. 3, the main body 9 of this embodiment has a rod-shaped connecting portion 17 that linearly extends and connects the front sides 15A and 15B of the clamping portions 13A and 13B that are arranged with a predetermined gap t in the left-right direction X of the column member 5. Further, as shown in FIG. 2, the hook portion 11 of this embodiment is erected obliquely upward from the outer sides 19A and 19B of the pair of clamping portions 13A and 13B toward the inside (center side).

[0024] In this embodiment, a rectangular plate-shaped screw fixing portion 21 is provided at the intermediate position in the left-right direction X of the connecting portion 17. Mounting holes 25 for screwing are formed in this screw fixing portion 21 for fixing the screw fixing portion 21 to the column member 5 using screws 23 (two in the vertical direction in this embodiment). The left and right clamping portions 13A and 13B, the connecting portion 17, the left and right hook portions 11A and 11B, and the screw fixing portion 21 are integrally joined by welding as an example to constitute the locking device 1.

[0025] As shown by the solid line in FIG. 2, in a state where the connecting portion 17 is in a horizontal posture, as shown in FIG. 3, the gap t between the left and right clamping portions 13A and 13B and the column member 5 is set to a dimension that allows the main body 9 to be fitted into the column member 5 with a margin. That is, the main body 9 is loosely fitted to the column member 5 from the horizontal direction H.

[0026] As shown by the solid line in Fig. 2, when the locking device 1 is loosely fitted to the column member 5 and then rotated (rotated clockwise in Fig. 2) about a horizontal axis as shown by the two-dot chain line in Fig. 2, the pair of clamping portions 13A and 13B come into contact with the column member 5 respectively. Thereby, the locking device 1 is attached to the column member 5. That is, when the main body 9 rotates about a horizontal axis, the gap t (see Fig. 3) disappears, and in this state, the inner sides 27A and 27B of the clamping portions 13A and 13B come into contact with the column member 5. Thereby, it is possible to prevent the locking device 1 from slipping downwards to V2. Incidentally, in advance, the locking device 1 may be inserted into the column member 5 in a posture slightly rotated (rotated clockwise in Fig. 4) about a horizontal axis, and may be slightly rotated about a horizontal axis so that the inner sides 27A and 27B of the clamping portions 13A and 13B come into contact with and bite into the column member 5.

[0027] As described above, in the present embodiment, a 3.5-inch square (10.5 cm square) square bar is used as the column member 5, and the dimensions of the locking device 1 are also set to dimensions corresponding to this column member 5. For example, the overall dimensions of the locking device 1 are a width of 200 mm, a depth of 83 mm, and a height of 43 mm, and the dimensions of the left and right clamping portions 13A and 13B are a width of 45 mm and a depth of 70 mm. Further, the interval between the inner sides 27A and 27B of the pair of clamping portions 13A and 13B into which the column member 5 is inserted is set to 110 mm. Thereby, in terms of design, a total gap t of 5 mm is ensured between the left and right clamping portions 13A and 13B and the column member 5. Although there are somewhat dimensional errors because the column member 5 is made of wood, by ensuring a total gap t of about 5 mm in terms of design, somewhat dimensional errors can be sufficiently absorbed. Further, the length of the connecting portion 17 is, for example, 200 mm, and the left and right clamping portions 13A and 13B and the connecting portion 17 are formed by, for example, deformed reinforcing bars with a diameter of 13 mm having irregularities on the surface.

[0028] The screw - fixing part 21 is composed of, for example, a metal plate with a width of 20 mm, a height of 30 mm, and a thickness of 4 mm. Two mounting holes 25 for screws with a diameter of 6 mm are provided vertically in the screw - fixing part 21. Further, the hook part 11 is composed of, for example, a metal round bar with a diameter of 7 mm and a length of 30 mm, and as shown in FIG. 2 etc., it is attached in an inclined posture at a predetermined angle on the inner side (center side).

[0029] Next, the installation procedure of the fall - prevention net 7 using the locking tool 1 of the present invention configured in this way will be described.

[0030] FIG. 4 is a view showing the usage state of the locking tool 1 shown in FIGS. 1 to 3. FIG. 5 is a plan view showing an example of the installation mode of the fall - prevention net.

[0031] First, the operator loosely fits the locking tool 1 to the column member 5 to which the locking tool 1 is to be attached, as shown in FIGS. 1 to 3, by fitting the locking tool 1 from the front side to the back side. In this case, for the direction of the locking tool 1, the side where the connecting part 17 is provided is the front Y1, and the side where the connecting part 17 is not provided is the back Y2.

[0032] Then, from the state where the locking tool 1 is loosely fitted to the column member 5, which is shown by the solid line in FIG. 2, the main body 9 is rotated clockwise around the horizontal axis as shown by the two - dotted chain line. Or, due to the relationship with the weight balance etc., the main body 9 rotates clockwise around the horizontal axis. That is, the locking tool 1 rotates in a direction to sandwich the gap t between the left and right clamping parts 13A, 13B and the column member 5. As a result, one - side edges 27A, 27B on the inner side of each of the left and right clamping parts 13A, 13B come into contact with the surface of the column member 5, and the locking tool 1 is attached to the column member 5 in a state where it does not slide downwards due to its own weight even if the hand is released from the locking tool 1.

[0033] Next, at the position of A shown by the dashed circle in Fig. 5, a reinforcing rope 8 or the like is hooked on one of the hook portions 11A or 11B of the clamping portions 13A and 13B that project left and right. Specifically, as shown in Fig. 4, a reinforcing rope 8 or the like at the periphery of the fall prevention net 7 is hooked on the hook portion 11B of the locking tool 1 attached to the column member 5.

[0034] Fig. 6 is a view showing an example of a mode of using both the hook portions 11A and 11B shown by B in Fig. 5. At the position of B shown by the dashed circle in Fig. 5, as shown in Fig. 6, a reinforcing rope 8 or the like is hooked on both the hook portions 11A and 11B of the clamping portions 13A and 13B that project left and right to stretch the fall prevention net 7. In Fig. 6, although the screwed state will be described in detail later, before screwing, as shown by the two-dot chain line, rotate the locking tool 1 to either one side, bring the inner sides 27A and 27B of the left and right clamping portions 13A and 13B into contact with the surface of the column member 5, attach the locking tool 1 to the column member 5, and then stretch the fall prevention net 7.

[0035] Furthermore, for the column member 5 located at a corner such as the position of C or D shown by the dashed circle in Fig. 5, it may be difficult to attach the locking tool 1 of the present invention at an optimal attachment position. In such a case, it is possible to attach a separate attachment (not shown) to the locking tool 1 for use. Alternatively, it is also possible to separately manufacture corner locking tools 41C and 41D as shown in the figure and use them in combination with the locking tool 1. It is also possible to directly attach the fall prevention net 7 to the column member 5 at the corner using screws, clamps, ropes, etc. Furthermore, if the fall prevention net 7 can be securely attached without using the column member 5 at the corner, it is also possible to omit the connection between the column member 5 at the corner and the fall prevention net 7.

[0036] With the fall prevention net 7 attached to all the fasteners 1, if a person or an object falls onto the fall prevention net 7, in the fastener 1 at the position A shown by the dashed circle in Fig. 5, as shown by the white arrow in Fig. 4, a load is applied downward V2 to the hook portion 11 on which the reinforcing rope 8 or the like is hooked. That is, a force tending to rotate in the rotational direction is applied to the fastener 1, and thereby, the inner sides 27A and 27B of the left and right clamping portions 13A and 13B respectively bite further into the surface of the column member 5 from the state of contacting the surface of the column member 5. Also, in the fastener 1 at the position B shown by the dashed circle in Fig. 5, as shown by the two-dot chain line in Fig. 6, the clamping portion 13A or the clamping portion 13B on the side of the fall prevention net 7 where a person or the like has fallen rotates downward so that the inner sides 27A and 27B of the left and right clamping portions 13A and 13B strongly contact the surface of the column member 5 and bite into the surface of the column member 5.

[0037] Thereby, the fall prevention net 7 is held at a predetermined height, and the fall of a person or the like can be safely prevented. That is, since safety is ensured immediately after the fall prevention net 7 is installed, the operator can immediately start the next work upstairs after the fall prevention net 7 is installed.

[0038] Also, after the fall prevention net 7 is installed, the operator gets on a stepladder or the like and drives a screw 29 into the mounting hole 25 formed in the screwing portion 21 as needed to perform the screwing work. Here, in the mode shown by A in Fig. 5, where the fastener 1 is tilted to one side and only one of the hook portions 11 is used, as shown in Fig. 4, the screwing is performed at two locations. In the case where the risk of the fastener 1 slipping downward V2 is small or the like, it is also possible to perform the screwing at one location or omit it.

[0039] In the mode using both the hook portions 11A and 11B on both sides shown in Fig. 6, the screwing is performed at one location. Thereby, as shown by the two-dot chain line, with the screwed screw 23 as the axis of rotation, the inner sides 27A and 27B of the left and right clamping portions 13A and 13B can rotate left and right within the range until they contact the surface of the column member 5.

[0040] Next, the results of the load tests conducted on the locking device 1 of the present invention and the conventional hanging tool 31 will be described.

[0041] The load test conducted on the locking device 1 of the present invention was a test to examine the breakage, etc. of the locking device 1 when a load was applied at a speed of 1 mm / min in the downward V2 direction of the vertical direction V to one hook portion 11. As the column member 5, a 3.5-inch square bar was used, and as the locking device 1, one having the dimensions described above was used as an example. In the state shown in FIG. 4, a load was applied from above to the right hook portion 11B to conduct the test.

[0042] The test results are as shown in FIG. 7. Due to the limitations of the test apparatus, the load could only be applied up to about 5000 N. However, even when a load of about 5000 N was applied, although the locking device 1 was displaced downward by about 33 mm, no breakage of the main body 9 or the hook portion 11, or falling off of the screws 23, etc. was observed. That is, it can be seen that the fall-prevention net 7 can be sufficiently held even when a load of about 5000 N is applied.

[0043] On the other hand, as the conventional hanging tool 31, as shown in FIGS. 8(a) and 8(b), a hook-shaped member with two screws 29 screwed into the beam member 33 was used. Load tests were conducted in two modes: when a load was applied in the horizontal direction H as shown in FIG. 8(a), and when a load was applied obliquely downward at 45° as shown in FIG. 8(b).

[0044] As a result, as shown in FIG. 8(a), when a load was applied in the horizontal direction H, the screw 29 in the upward V1 broke at about 3000 N, and the screw 29 in the downward V2 fell out of the beam member 33. On the other hand, as shown in FIG. 8(b), when a load was applied obliquely downward at 45°, the screw 29 in the upward V1 broke at about 4500 N, and the screw 29 in the downward V2 fell out of the beam member 33.

[0045] Therefore, it can be seen that the locking device 1 of the present invention can withstand a larger load compared to the conventional hanging tool 31, and the safety has been significantly improved. In particular, even when a large load is applied to the hook portion 11 from above, the load applied to the screw 23 can be kept small, so the risk of breakage or loosening of the screw 23 is significantly reduced.

[0046] As described above, the locking device 1 of the present invention is easy to install, has excellent workability, and also has excellent holding power for the fall prevention net.

[0047] The locking device 1 for the fall prevention net of the present invention is not limited to the configuration described in the above-described embodiment, and various modifications can be made within the scope described in the claims. For example, in the above-described embodiment, a 3.5-inch square (10.5 cm square) square bar was used as the column member 5, but other square bars of different sizes such as 4-inch square (12 cm square) can also be used as the column member 5. When using square bars of different sizes as the column member 5 in this way, the length of the connecting portion 17 and the interval between the left and right clamping portions 13A and 13B may be appropriately adjusted according to the size of the column member 5 to be used.

[0048] Also, the gap t between the left and right clamping portions 13A and 13B of the locking device 1 attached to the column member 5 and the column member 5 can be set wider within a range where the locking device 1 does not slide downward to V2. In this case, for example, it is also possible to use a locking device 1 that can be used for both of the two types of column members 5 with different sizes of 3.5-inch square (10.5 cm square) and 4-inch square (12 cm square). Furthermore, in the above-described embodiment, the mode including the left and right hook portions 11A and 11B was described as an example, but a mode including only one of the hook portions 11 may also be used.

[0049] Also, in the above-described embodiment, the rectangular frame-shaped clamping portion 13 was described as an example, but the shape is not particularly limited as long as it has a portion that contacts the column member 5 and a portion where the hook portion 11 is provided. Furthermore, the shape of the hook portion 11 is not limited, such as one that stands up vertically or a hook shape.

[0050] In the above-described embodiment, the main body 9 is formed by welding deformed reinforcing bars. However, the main body 9 may be integrally formed by casting or the like, or the main body 9 and the hook portion 11 may be integrally formed together. Further, in the above-described embodiment, the installation method of screwing after hooking the fall prevention net 7 to the hook portion 11 of the fixture 1 has been described as an example. Although the timing of installing the fall prevention net 7 is slightly delayed, an installation method of hooking the fall prevention net 7 to the hook portion 11 of the fixture 1 after screwing can also be adopted.

[0051] In the above-described embodiment, both the mode of using only one of the hook portions 11 and the mode of using both of the hook portions 11 are used together. For example, in FIG. 5, when installing one fall prevention net 7, it can be dealt with only by the mode of using only one of the hook portions 11.

Explanation of Reference Numerals

[0052] 1 Fixture (for fall prevention net) 3 Building structure body 5 Column material 7 Fall prevention net 8 Reinforcing rope 9 Main body 11 Hook portion 13 Clamping portion 15 One side (front side) 17 Connecting portion 19 One side (outer side) 21 Screwing portion 23 Screw 25 Mounting hole 27 One side (inner side) 29 Screw 31 Suspension tool 33 Beam material H Horizontal direction X Left - right (direction) Y Front - rear direction V Vertical direction t Gap

Claims

1. It comprises a main body that is loosely fitted from the horizontal direction to a column member of a building structure body, and a hook portion provided on the main body for hooking a fall prevention net. The main body has a pair of clamping portions respectively arranged on the left and right of the column member, and a connecting portion connecting the pair of clamping portions. When it rotates about a horizontal axis from a state of being loosely fitted to the column member, the pair of clamping portions respectively abut against the column member and are attached. The hook portion is provided on at least one of the pair of clamping portions, and is a locking device for a fall prevention net.

2. Each of the pair of clamping portions has a rectangular frame shape. The connecting portion constitutes one side of the pair of clamping portions and connects the two. The hook portion is raised upward from one outer side of each of the pair of clamping portions, and is a locking device for a fall prevention net according to Claim 1.

3. The connecting portion is provided with a screwing portion at an intermediate position in the left-right direction. The screwing portion is provided with a mounting hole for screwing, and is a locking device for a fall prevention net according to Claim 1 or 2.

4. The main body is formed by deformed reinforcing bars with uneven surfaces, and is a locking device for a fall prevention net according to Claim 1.

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