JP2004230411A - Chain with hook and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hook-attached chain having high mechanical strength and also to provide its manufacturing method while investment in the equipment is reduced by half. <P>SOLUTION: This chain is a hook-attached chain 1 including a chain body 3 which is composed of a plurality of links 2 connected with each other and a hook member 5 which is attached to at least one end of the chain body 3 with the middle of one link 2 put through the attaching hole 4 of the hook. As the link for connecting between the links 2, a first link 7 is used which is formed with a flash-free part 6 by removing a welding flash in the middle of the link. As the link for attaching the hook member 5, a second link 9 is used in which a welding flash 8 remains in the middle of the link. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chain with a hook that can be suitably used as a chain for a suspended scaffold.
[0002]
[Prior art]
As a scaffold used for building construction and renovation of exterior walls, hanging scaffolds that support a scaffold by wrapping a chain around a beam of a building are widely used when constructing a bridge girder such as a highway. . Further, as such a chain for a suspended scaffold, a chain body formed by connecting a plurality of links, and a pair of hook members attached to both ends of the chain body by inserting a middle portion of the link into a mounting hole. (See, for example, Patent Document 1).
[0003]
Usually, such a chain with a hook is manufactured by manufacturing a chain in which a plurality of links are connected, cutting the chain to a set length, inserting a link wire into both ends of the cut chain, and forming a hook member. The link wire is formed into a link shape by inserting the mounting hole, and then both ends of the link wire are welded and joined. For this reason, the facility for manufacturing a chain with a hook is composed of two facilities: a facility for connecting the links and a facility for connecting the link and the hook member.
[0004]
On the other hand, as a method of manufacturing a chain, there is a method in which welding is carried out while pressing both ends of a link wire so that the tip of the welding burr is non-sharp, and a method of manufacturing a link in which the tip of the welding burr is sharp. A method is known in which a wire is welded and joined while strongly pressing both ends thereof, and then the welding burrs are removed to manufacture the wire.
[0005]
[Patent Document 1]
JP-A-2000-96818 (page 2, FIG. 1, FIG. 3)
[0006]
[Problems to be solved by the invention]
In the former manufacturing method, while the mechanical performance such as the tensile strength and bending strength of the chain is sufficiently secured, the tip of the welding burr is non-sharp, so it is possible to prevent fingers from being cut when using the chain. Since the post-process for removing welding burrs can be omitted and the manufacturing equipment can be configured at low cost, it is currently most widely adopted as a method for manufacturing chains for hanging scaffolds. However, in recent years, from the demand for further improvement in safety, as a result of conducting various strength tests, in the chain manufactured by the former manufacturing method, if the link of the chain once bends due to the bending load, the bent link It has been confirmed that cracks easily occur in the welded portion, and the tensile strength of the link after bending is greatly reduced. In addition, an annular depression is formed in the outer peripheral portion of the welding burr, stress is easily generated in this depression, and since the welding burr is configured to be non-sharp, it is difficult to sufficiently push out the welding burr. In some cases, impurities such as iron oxide may remain, so that it is difficult to set the strength of the welded portion higher than the current level.
[0007]
Further, in the latter manufacturing method, since the both ends of the link wire are strongly pressed and welded, it is possible to prevent impurities from remaining at the joint, and to remove welding burrs in a post-process after welding. , The mechanical performance such as the tensile strength and bending strength of the chain can be sufficiently secured, and sufficient mechanical strength can also be secured with respect to the tensile strength after bending deformation. However, in order to ensure the handleability of the chain, since the work of removing welding burrs in the subsequent process is an indispensable step, the manufacturing cost of the manufacturing equipment is several tens times higher than the manufacturing equipment that does not remove the welding burrs There was a problem of becoming.
[0008]
Further, in order to further increase the strength of the chain, it is preferable that the chain be manufactured by the latter manufacturing method. However, in the case of a chain with a hook, as described above, the facility for connecting the links and the link and the hook member are used. To switch the equipment from the former manufacturing method to the latter manufacturing method, it is necessary to replace two equipments, which are several tens of times more expensive than the former manufacturing equipment. However, there is a problem that a heavy burden is imposed on a manufacturer.
[0009]
An object of the present invention is to provide a chain with hooks having high mechanical strength and a method for manufacturing the same, while reducing capital investment by half.
[0010]
[Means for Solving the Problems]
The present inventor has noted that in a chain for a suspended scaffold, a large bending load is not applied to a link at a chain end to which a hook member is attached. Is welded while pressing both ends of the link wire so as to be sharp, and then using the welding burrs removed.For the link for attaching the hook member, the tip of the welding burr is made non-sharp. By using a wire made by welding while pressing both ends of the link wire, it is possible to improve the mechanical strength of the chain while reducing capital investment by half, and to manufacture a chain without a hook member. The present invention was completed based on the idea that the newly installed equipment can be used effectively.
[0011]
A chain with a hook according to claim 1, comprising: a chain main body formed by connecting a plurality of links; and a hook member attached to at least one end of the chain main body by inserting a middle portion of the link into an attachment hole. A first link having a deburring portion formed by removing welding burrs in the middle of the link as a link for connecting the links, and a welding burr in the middle of the link as a link for attaching the hook member. The remaining second link is used.
[0012]
In this chain with hooks, the first link connecting the links is formed by a link having a deburring portion formed by removing welding burrs in the middle of the link, so it is necessary to newly provide a manufacturing facility capable of removing burrs. However, since the welding can be performed while strongly pressing the both ends of the link wire, the strength of the welded part is high, and a very safe chain that can secure sufficient strength against the tensile load after bending deformation Can be realized. In addition, since the second link for attaching the hook member to the chain body is constituted by a link in which welding burrs are left in the middle of the link, the strength against a tensile load after bending deformation is low, but the second link is generally used. Can secure sufficient mechanical strength and can be manufactured using existing manufacturing equipment as it is, so that there is no economical burden on equipment.
[0013]
On the other hand, the chain with hooks can be applied to various uses.For example, when applied to an application in which a large bending load is not applied to a link near the hook member such as a chain for a hanging scaffold, a link for attaching the hook member to the chain body is used. The second link is adopted to reduce the equipment economical load by half and to prevent a large bending load from acting on the second link, and to improve the safety and reliability of the hooked chain while using the second link. It is possible to improve as much as a chain with a hook consisting only of the first link. Moreover, since the first link manufacturing equipment can be used for manufacturing a chain without a hook, the quality of the entire chain product can be improved by effectively utilizing newly installed equipment.
[0014]
A method of manufacturing a chain with a hook according to the present invention includes a hook having a chain body formed by connecting a plurality of links, and a hook member attached to at least one end of the chain body by inserting a middle portion of the link into an attachment hole. A method of manufacturing a chain with a link, wherein the first link for connecting the links is formed by forming a first link wire having a predetermined length into a link shape, and then forming a first end of the welding burr such that the tip of the welding burr is sharp. After welding and joining both ends of the 1-link wire while pressing the same, the welding burrs are removed and the second link for attaching the hook member is formed by linking a second link wire having a predetermined length to the link shape. And then welded together while pressing both ends of the second link wire so that the tip of the welding burr is not sharp.
[0015]
In this method of manufacturing a chain with hooks, the first link connecting the links is welded and joined while pressing both ends of the first link wire so that the tip of the welding burr is sharp. Therefore, it is necessary to newly install a production facility capable of removing burrs, but since welding can be performed while strongly pressing both ends of the first link wire, impurities can be prevented from remaining in the welded portion, and Since welding burrs are removed after welding, the occurrence of stress concentration in the welded portion can be prevented, the strength of the welded portion can be increased, and sufficient strength against tensile load after bending deformation can be ensured. Can be configured with high links.
[0016]
Also, the second link for attaching the hook member to the chain body is manufactured by welding and joining while pressing both ends of the second link wire so that the tip of the welding burr is not sharp. Although the strength against the tensile load after the deformation is low, the mechanical strength in normal use can be sufficiently ensured, and it can be manufactured using existing manufacturing equipment as it is, so that there is no economical load on the equipment.
[0017]
For this reason, in the case of a chain with a hook manufactured in this way, similarly to the chain with a hook described above, when applied to an application in which a large bending load does not act on the link near the hook member, for example, a chain for a hanging scaffold, The second link is used as a link for attaching the hook member to the chain body, so that the facility economic load is reduced by half, and a large bending load is not applied to the second link. The safety and reliability of the chain with hooks can be improved as well as the chain with hooks consisting of only the first link. In addition, since the first link manufacturing equipment can be used for manufacturing a chain without a hook, the quality of the chain can be improved by effectively utilizing newly installed equipment.
[0018]
Here, as the first link wire, a part or whole of the outer periphery of both ends is chamfered, and a chain formed by connecting a plurality of the first links is manufactured. Then, a hook member is connected to the end of the chain using a second link, and the like is a preferred embodiment.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, a chain 1 with a hook has a chain body 3 formed by connecting a plurality of links 2 and at least one end of the chain body 3 by inserting an intermediate portion of the link 2 into a mounting hole 4. And a hook member 5 attached to the main body.
[0020]
The link 2 of the chain body 3 that connects the links 2 is composed of a first link 7 having a burr removing portion 6 formed by removing a welding burr at an intermediate portion, and the hook member 5 is attached to the chain body 3. The link 2 is constituted by a second link 9 in which a welding burr 8 remains in the middle. The hook member 5 may have any configuration as long as it has the mounting hole 4 for the second link 9. Further, the hook member 5 can be attached to only one end of the chain body 3.
[0021]
Next, a method for manufacturing the chain 1 with hooks will be described.
This manufacturing method basically includes a chain manufacturing step of sequentially connecting the first links 7 to form a long chain, cutting the long chain to a set length, and then attaching the cut ends to both ends of the cut chain. It comprises two steps of a hook attaching step of attaching the hook member 5 using the second link 9.
[0022]
First, a chain manufacturing process for manufacturing a long chain by sequentially connecting the first links 7 will be described.
As shown in FIG. 3A, a pair of notch portions 11 are formed at regular intervals corresponding to substantially the circumference of the first link 7 on the wire 10 using a pair of front and rear V notch blades 20. I do.
[0023]
Next, as shown in FIG. 3B, the wire 10 having the notch 11 is inserted into the fixed cutter 21, and the movable cutter 23 is moved forward with the clamp 22 holding the vicinity of the end of the wire 10. Then, the wire 10 is cut at the notch portion 11 to produce a first link wire 13 having a set length in which chamfers 12 are formed before and after both ends. Note that a chamfer may be formed on both ends of the first link wire over the entire circumference.
[0024]
Next, as shown in FIG. 3C, the first link 7 produced immediately before is set in the concave groove 25 of the middle plate 24 in the vertical direction, and the first link 7 is inserted so that the first link 7 is inserted. The wire rod 13 for link is transferred to the front side of the middle plate 24 and set, and a substantially central portion in the longitudinal direction of the first wire rod 13 for link is pressed by the back pushing part 26 toward the concave portion 27 side of the middle plate 24, and The first link wire 13A having the curved portion 14 in the portion is manufactured. However, when manufacturing the first first link 7, nothing is set in the concave groove 25 of the middle plate 24.
[0025]
Next, in a state where the first link wire 13A is placed on the middle plate 24 as it is, as shown in FIG. 3D, while pressing the left bending roller 28 against the first link wire 13A, the first link wire 13A is pressed. The first link wire 13B is manufactured by bending the left half of the wire 13A along the outer surface of the middle plate 24.
[0026]
Next, as shown in FIG. 3E, the right half of the first link wire 13B is curved along the outer surface of the intermediate plate 24 while pressing the right bending roller 29 against the first link wire 13B. The first link wire 13C having a substantially oval link shape is manufactured. However, after bending the right half, the left half may be bent.
[0027]
Next, as shown in FIG. 4 (a), a pair of left and right electrode clamps 30 is attached to both ends of the first link wire 13C, and an upset tool 31 is provided on both longitudinal sides of the first link wire 13C. As shown in FIG. 4B, the first link wire 13C is pressed inward by the upset tool 31 while energizing the two electrode clamps 30, and both ends of the first link wire 13C are pressed. Welding while pressing is performed to obtain the first link wire 13D. At this time, since the chamfered portions 12 are formed at both ends of the first link wire 13C, both ends of the first link wire 13C are welded by generating heat from a portion near the axis thereof. In addition, the occurrence of poor welding at the center is prevented, and the welded portion is pressed with a large upset force (for example, 11.76 kN). Is formed over the entire circumference.
[0028]
Next, as shown in FIG. 5, in a state where the first link wire 13D is held by the upset tool 31, before and after the welding burr 15 (inside and outside the ring) with a burr cutter 33 having a pair of front and rear blades 32. By removing the portion, the first link wire 13E is manufactured.
[0029]
Next, as shown in FIG. 6, while the first link wire 13E is held by the upset tool 31, the remaining welding burrs 15 are removed by an arc burr cutter 35 having a pair of upper and lower blades 34. Then, the first link 7 having the columnar deburred portion 6 slightly raised from the other portions is manufactured.
[0030]
In this way, by repeating the above operation, a long chain connecting the plurality of first links 7 is sequentially manufactured, and this is cut into a set length.
[0031]
Next, a description will be given of a hook attaching step of attaching the hook member 5 to the both ends of the chain having the set length including the first links 7 manufactured as described above using the second links 9. However, since the method of attaching the hook members 5 to both ends of the chain is the same, only the method of attaching one hook member 5 will be described.
First, as shown in FIG. 7 (a), a second link wire 40 made by bending a wire into a C-shape is manufactured, and the second link wire 40 is attached to the first link 7 at one end of the chain. At the same time, and through the mounting hole 4 of the hook member 5.
[0032]
Next, as shown in FIG. 7 (b), the second link wire 40 is set substantially horizontally in a housing (not shown) so that both ends are located on the rear side, and is pressed by the pressing metal fitting 51 from behind. The wire 40A is pressed forward and the wire 40 for the second link is pressed into a link shape to manufacture the wire 40A for the second link.
[0033]
Next, as shown in FIG. 7C, the upper pair of upper electrodes 52 and the lower pair of lower electrodes 53 are connected to both ends of the second link wire 40A, respectively. The upset plates 54 arranged on the left and right sides of the 40A are brought closer to each other, and both upper and lower electrodes 52, 53 are energized while pressing both ends of the second link wire 40A between the two upset plates 54, Both ends of the second link wire rod 40A are welded, and the hook member 5 and the first link 7 are connected by the second link 9, as shown in FIG. At this time, a welding burr 8 is formed in the welding portion. Since the upsetting force of the welding burr 8 is set to a relatively low value (for example, 4.9 kN), the outer peripheral portion of the welding burr 8 is non-sharp. It is formed in a chevron-shaped cross section, and if it is left as it is, it does not hurt the finger when using the chain, etc., so that it is left without being removed.
[0034]
As described above, in the chain 1 with hooks, the link 2 connecting the links 2 is constituted by the first link 7 having the burr removing portion 6 formed by removing the welding burr 15 in the middle of the link. Although it is necessary to newly establish a manufacturing facility capable of removing burrs, since welding can be performed while strongly pressing both ends of the first link wire 13C, the strength of the welded portion is high and sufficient for tensile load after bending deformation. It is possible to realize an extremely safe chain that can secure high strength. Further, since the link 2 for attaching the hook member 5 to the chain body 3 is constituted by the second link 9 in which the welding burr 8 is left in the middle of the link, the strength against the tensile load after the bending deformation is reduced. However, the mechanical strength in normal use can be sufficiently ensured, and it can be manufactured using existing manufacturing equipment as it is, so that there is no economical burden on the equipment.
[0035]
On the other hand, the chain 1 with hooks can be applied to various uses. For example, when the chain 1 with hooks is applied to an application in which a large bending load does not act on the link 2 near the hook member 5 such as a chain for a suspended scaffold, the chain can be used. The second link 9 is adopted as the link 2 to be attached to the main body 3 so that a large economical load is not applied to the second link 9 while halving the facility economic load. The safety and reliability of the chain with hooks 1 can be improved as well as the chain with hooks including only the first link 7. In addition, since the manufacturing equipment for the first link 2 can be used for manufacturing a chain without a hook, the quality of the chain can be improved by effectively utilizing newly installed equipment.
[0036]
For example, when the chain with hooks 1 is used as a hanging scaffold, as shown in FIG. 8, the first end side of the chain main body 3 is wound around a beam 60 of a building, and the hook member 5 at the first end is used. Is engaged with the vicinity of the upper end of the chain body 3 extending from the beam 60 to the second end, the second end side of the chain body 3 is wound around the parent pipe 61 of the scaffold, and the hook member 5 at the second end is removed from the beam 60. The scaffold is suspended from the beam 60 by engaging with the vicinity of the lower end of the chain extending to the side. While the scaffold is suspended, a load in the bending direction acts on the corners of the beam 60 and the link 2 located below the parent pipe 61. However, the link 2 near the hook member 5 Since the second link 9 is connected linearly, almost no bending load acts on the second link 9.
[0037]
Note that a metal pipe member may be provided on the second link 9 so as to receive a bending load on the second link 9 to further improve the safety of the chain with hooks.
[0038]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the chain with a hook and the manufacturing method thereof according to the present invention, when applied to a chain with a hook or a method of manufacturing the chain for use in which a large bending load does not act on a link near a hook member, such as a chain for a suspended scaffold In addition, the second link is used as a link for attaching the hook member to the chain body, so that the equipment economic load is reduced by half, and a large bending load is not applied to the second link. The safety and reliability of the chain with the hook can be improved as well as the chain with the hook including only the first link. Moreover, since the first link manufacturing equipment can be used for manufacturing a chain without a hook, the quality of the entire chain product can be improved by effectively utilizing newly installed equipment.
[0039]
Here, in the above-mentioned manufacturing method, if the first link wire is formed by chamfering a part or all of the outer periphery of both ends, when welding while pressing both ends of the first link wire, Since heat is generated from the central portion of the 1-link wire and welded, impurities can be pushed out from the central portion to the outer edge side, and the occurrence of welding defects at the central portion can be prevented.
[0040]
After manufacturing a chain formed by connecting a plurality of the first links, cutting the chain into a chain of a set length, and connecting a hook member to an end of the chain using a second link, the first link is manufactured. It is possible to increase the operation efficiency of expensive manufacturing equipment for performing the operation.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a chain with a hook. FIG. 2 is a front view of a main part of a chain with a hook. FIGS. 3 (a) to 3 (e) are explanatory views of a method of manufacturing a first link. FIGS. 5 (a) and 5 (b) are explanatory views of a method of manufacturing a first link. FIGS. 5 (a) and 5 (b) are cross-sectional views taken along line AA of FIG. 6 (a). (A) is an explanatory view of a method of manufacturing the first link, (b) is a sectional view taken along the line BB of (a). [FIG. 7] An explanatory view of a method of manufacturing the second link. Explanatory drawing of a hanging scaffold chain using a chain with hooks [Description of reference numerals]
DESCRIPTION OF SYMBOLS 1 Chain 2 Link 3 Chain main body 4 Mounting hole 5 Hook member 6 Deburring part 7 First link 8 Welding burr 9 Second link 10 Wire 11 Notch part 12 Chamfered part 13 First link wire 13A First link wire 13B First link wire 13C First link wire 13D First link wire 13E First link wire 14 Curved portion 15 Weld burr 20 Notch blade 21 Fixed cutter 22 Clamp 23 Movable cutter 24 Middle plate 25 Depressed groove 26 Back pushing portion 27 concave portion 28 left bending roller 29 right bending roller 30 electrode clamp 31 upset tool 32 blade 33 burr cutter 34 blade 35 arc burr cutter 40 link wire 40A link wire 50 upper holding mold 51 press fitting 52 upper electrode 53 lower electrode 54 Upset plate 60 Beam 61 Parent pipe

Claims (5)

A chain with a hook having a chain body formed by connecting a plurality of links and a hook member attached to at least one end of the chain body by inserting a middle part of the link into an attachment hole,
As a link for connecting the links, a first link having a deburring portion formed by removing welding burrs in the middle of the link is used,
As a link for attaching the hook member, a second link having welding burrs left in the middle of the link was used.
A chain with a hook, characterized in that: The chain with a hook according to claim 1, which is used as a chain for a suspended scaffold. A method of manufacturing a chain with hooks, comprising: a chain main body formed by connecting a plurality of links; and a hook member attached to at least one end of the chain main body by inserting a middle part of the link into an attachment hole,
The first link for connecting the links is formed by forming a first link wire having a predetermined length into a link shape, and then pressing both ends of the first link wire so that the tips of the welding burrs are sharp. After welding and joining, remove the welding burr and manufacture
The second link for attaching the hook member is formed by forming a second link wire having a predetermined length into a link shape, and then forming both ends of the second link wire so that the tips of the welding burrs are not sharp. It was manufactured by welding and joining while pressing.
A method for manufacturing a chain with a hook, characterized in that: 4. The method for manufacturing a chain with hooks according to claim 3, wherein the first link wire is formed by chamfering a part or all of the outer periphery of both ends. 5. A chain formed by connecting a plurality of the first links, cutting the chain into a chain of a set length, and connecting a hook member to an end of the chain using a second link. Manufacturing method of chain with hook.

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