Plumb bob

Abstract

To provide a weight which is easily attached to and detached from a hanging load rope.SOLUTION: A weight according to one aspect of the present invention is a weight through which a hanging load rope that is suspended from a derricking member of construction machinery is inserted to detect overwinding of the hanging load rope, the weight is provided with a pair of cylindrical parts that is disposed at a prescribed interval in the vertical direction, and a coupling part that is coupled to the pair of cylindrical parts, and a slit for inserting and withdrawing the hanging load rope is formed in each of the pair of the cylindrical parts.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a plumb bob.

Background Art

[0002] In construction machines such as cranes, a plumb bob is used to detect overwinding of a suspension rope that hangs down from a heaving member such as a jib. This plumb bob is suspended by a wire rope or the like attached to a limit switch disposed on the heaving member. This plumb bob is cylindrical and has an insertion hole through which the suspension rope passes. When the suspension rope is wound up, the hook suspended from this suspension rope contacts from below and is lifted together with this hook. As a result, the force applied to the limit switch decreases, and overwinding of the suspension rope can be detected (see Japanese Unexamined Patent Application Publication No. 2013-18616).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The plumb bob described in Patent Document 1 is suspended by a wire rope, and the suspension rope is inserted from one end side of the insertion hole. Therefore, according to the plumb bob described in Patent Document 1, after passing the suspension rope through the insertion hole, it is necessary to attach a hook to this suspension rope.

[0005] Therefore, according to the weight described in Patent Document 1, it is necessary to insert the suspension rope into the weight before attaching the hook to the suspension rope, and it is necessary to attach and detach the suspension rope and the hook each time the weight is attached and detached, resulting in poor workability for attaching and detaching the weight.

[0006] Note that Patent Document 2 describes a weight having a partial cylindrical weight body having a rope passage allowance space that traverses in the axial direction, a detachable member detachably attached to the weight body so as to block the rope passage allowance space of the weight body, and a fastener for fastening the detachable member to the weight body. According to the weight described in Patent Document 2, it is possible to insert and remove the rope inside and outside the weight through the rope passage allowance space. However, according to this configuration, in order to prevent the unintentional removal of the rope from the rope allowance space, it is necessary to block the rope allowance space with the detachable member and further fasten the detachable member to the weight body using the fastener. Therefore, there is still room for improvement in terms of the attachability and detachability of the weight described in Patent Document 2 with respect to the rope.

[0007] The present invention has been made based on such circumstances, and an object thereof is to provide a weight that is easily attachable and detachable to and from a suspension rope.

Means for Solving the Problems

[0008] A weight according to one aspect of the present invention is a weight through which a suspension rope for detecting overwind of the suspension rope suspended from a hoisting member of a construction machine is inserted, and includes a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, and slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions.

Effects of the Invention

[0009] A weight according to one aspect of the present invention is easily attachable and detachable to and from a suspension rope.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0011] [Description of Embodiment of the Present Invention] First, embodiments of the present invention will be listed and described.

[0012] A weight according to one aspect of the present invention is a weight through which a suspension rope is inserted to detect overwinding of the suspension rope suspended from an undulating member of a construction machine, and includes a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, and slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions.

[0013] The weight can insert and remove the suspension rope through the slit into and out of the cylindrical portion. Therefore, the weight can be easily attached to and detached from the suspension rope. Further, since the weight includes the pair of cylindrical portions arranged at intervals in the vertical direction, it is easy to prevent the suspension rope from unintentionally coming out of the weight.

[0014] The connecting part may be rod-shaped, plate-shaped, string-shaped or chain-shaped. Thus, since the connecting part is rod-shaped, plate-shaped, string-shaped or chain-shaped, it is easy to arrange the pair of cylindrical parts in a vertically spaced state.

[0015] The connecting part may be detachably provided with at least one of the pair of cylindrical parts. Thus, since the connecting part is detachably provided with at least one of the pair of cylindrical parts, for example, after inserting the suspension load rope into the slit provided in the pair of cylindrical parts, the connecting part can be connected to the cylindrical part. According to this configuration, it is easy to attach and detach the weight to and from the suspension load rope.

[0016] The connecting part may be arranged between the pair of slits provided in the pair of cylindrical parts. Thus, since the connecting part is arranged between the pair of slits provided in the pair of cylindrical parts, it is possible to easily and surely prevent the suspension load rope from unintentionally coming out of the pair of cylindrical parts.

[0017] The center lines of the pair of slits may not coincide. Thus, since the center lines of the pair of slits do not coincide, it is possible to easily prevent the suspension load rope from unintentionally coming out of the pair of cylindrical parts.

[0018] The center lines of the pair of slits may be non-parallel. Thus, since the center lines of the pair of slits are non-parallel, it is possible to easily prevent the suspension load rope from unintentionally coming out of the pair of cylindrical parts.

[0019] It is preferable that the pair of slits have inclined portions that are inclined with respect to the vertical direction. Thus, by having the pair of slits have inclined portions that are inclined with respect to the vertical direction, it is possible to easily suppress the unintentional extraction of the suspension load rope from the pair of cylindrical portions.

[0020] It is preferable that the inclination directions of the pair of inclined portions provided in the pair of slits are opposite to each other. Thus, by having the inclination directions of the pair of inclined portions provided in the pair of slits be opposite to each other, it is possible to more easily suppress the unintentional extraction of the suspension load rope from the pair of cylindrical portions.

[0021] It is preferable that the inner diameter of the upper cylindrical portion among the pair of cylindrical portions is larger than the inner diameter of the lower cylindrical portion. Thus, by having the inner diameter of the upper cylindrical portion among the pair of cylindrical portions be larger than the inner diameter of the lower cylindrical portion, it is possible to easily detect overwinding of the suspension load rope while suppressing contact between the weight and the suspension load rope.

[0022] In the present invention, the "vertical direction" means the vertical direction in the installed state in the construction machine. "Rod-shaped" means an elongated shape, and includes a shape that is linearly extended in the longitudinal direction, as well as a curved or bent shape. "Plate-shaped" means a shape in which the thickness is small compared to the length and width. "The center lines of the pair of slits are non-parallel" means that the angle formed by the center lines of the pair of slits is 5° or more.

[0023] [Details of Embodiments of the Present Invention] Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the drawings.

[0024] [First Embodiment] <Construction Machine> As shown in FIGS. 1 and 2, the construction machine 1 includes a lower traveling body 2, an upper slewing body 3 mounted on the lower traveling body 2 so as to be horizontally rotatable, and a lifting member 4 attached to the upper slewing body 3 so as to be liftable. In this embodiment, the construction machine 1 is a crane. The lifting member 4 has a boom 4a attached to the upper slewing body 3 so as to be liftable, a jib 4b connected to the tip of the boom 4a so as to be liftable, and a sheave 4c provided at the tip of the jib 4b. Further, the construction machine 1 includes a load rope 5 suspended from the lifting member 4, a limit switch 6 fixed to the lifting member 4, a string-like portion 7 connected to the limit switch 6 and suspended from the lifting member 4, a weight 10 suspended by the string-like portion 7, and a hook 8 suspended by the load rope 5. As shown in FIG. 3, the string-like portions 7 are suspended from both the left and right sides of the lifting member 4. Examples of the string-like portion 7 include a wire rope, a chain, and a link. When the load rope 5 is wound up, the construction machine 1 is configured to be able to detect overwinding of the load rope 5 by the hook 8 coming into contact with the weight 10 from below and the force applied to the limit switch 6 decreasing. In this specification, "front", "rear", "left and right" mean "front", "rear", and "left and right" when the tip side of the lifting member (for example, the jib or the boom) from which the load rope is suspended is defined as the front side and the base end side is defined as the rear side.

[0025] <weight> The weight 10 has a suspension rope 5 inserted therethrough for detecting overwinding of the suspension rope 5 that hangs down from the undulating member 4. As shown in FIGS. 2 to 5, the weight 10 includes a pair of cylindrical portions 11 and 12 (hereinafter, the upper cylindrical portion is referred to as the "first cylindrical portion 11", and the cylindrical portion disposed below the first cylindrical portion 11 is also referred to as the "second cylindrical portion 12") arranged at intervals in the vertical direction, and a connecting portion 13 connected to the pair of cylindrical portions 11 and 12. The pair of cylindrical portions 11 and 12 are connected to each other by a plurality of connecting portions 13. Further, the weight 10 includes a pair of mounting portions 14 connected to the first cylindrical portion 11 and connected to the string-like portion 7. The weight 10 is composed of a pair of cylindrical portions 11 and 12, a plurality of connecting portions 13, and a pair of mounting portions 14. Slits 11a and 12a for inserting and removing the suspension rope 5 are respectively formed in the pair of cylindrical portions 11 and 12 (hereinafter, the slit formed in the first cylindrical portion 11 is referred to as the "first slit 11a", and the slit formed in the second cylindrical portion 12 is also referred to as the "second slit 12a").

[0026] (Cylindrical portion) The cylindrical portions 11 and 12 penetrate in the vertical direction and have insertion holes through which the suspension rope 5 is inserted. The pair of cylindrical portions 11 and 12 are provided so as to surround the periphery of the suspension rope 5 with a space therebetween. The lengths in the central axis direction, thicknesses (thicknesses in the radial direction), etc. of the cylindrical portions 11 and 12 are not particularly limited. That is, the cylindrical portions 11 and 12 may have an elongated shape in the central axis direction, or may have a ring shape or a disk shape with a small length in the central axis direction. The cross-sectional shape perpendicular to the central axis direction of the cylindrical portions 11 and 12 is not particularly limited, and examples thereof include an annular shape and a polygonal annular shape, and an annular shape is preferred. The inner diameter and outer diameter of the cylindrical portions 11 and 12 are preferably uniform over the central axis direction thereof.

[0027] The sizes of the pair of cylindrical portions 11 and 12 may be the same or different. When the sizes of the pair of cylindrical portions 11 and 12 are different, for example, the inner diameter of the first cylindrical portion 11 may be made larger than the inner diameter of the second cylindrical portion 12. Since the second cylindrical portion 12 needs to contact the hook 8 during overwinding of the suspension load rope 5, its inner diameter is limited to a relatively small value. On the other hand, since the first cylindrical portion 11 is not scheduled to contact the hook 8, it is preferable to make the inner diameter larger than that of the second cylindrical portion 12 so as to suppress unintentional contact with the suspension load rope 5 even when the center of gravity of the weight 10 is displaced. From this viewpoint, the weight 10 can suppress contact between the weight 10 and the suspension load rope 5 by making the inner diameter of the first cylindrical portion 11 larger than the inner diameter of the second cylindrical portion 12, thereby suppressing damage to the suspension load rope 5 and wear of the weight 10, and can easily detect overwinding of the suspension load rope 5.

[0028] The pair of cylindrical portions 11 and 12 are preferably arranged parallel to each other such that their central axes extend in the vertical direction.

[0029] The slits 11a and 12a cross the cylindrical portions 11 and 12 in the central axis direction. The center lines of the pair of slits 11a and 12a preferably do not coincide. According to this configuration, unintentional extraction of the suspension load rope 5 from the pair of cylindrical portions 11 and 12 can be easily suppressed. Further, from the viewpoint of more reliably suppressing unintentional extraction of the suspension load rope 5, as shown in FIG. 5, a first virtual region R1 obtained by extending the first slit 11a along its shape toward the second cylindrical portion 12 does not intersect with an end portion 12b of the second slit 12a on the first cylindrical portion 11 side, and a second virtual region R2 obtained by extending the second slit 12a along its shape toward the first cylindrical portion 11 does not intersect with an end portion 11b of the first slit 11a on the second cylindrical portion 12 side.

[0030] The center lines of the pair of slits 11a and 12a are preferably non-parallel. According to this configuration, unintentional extraction of the suspension load rope 5 from the pair of cylindrical portions 11 and 12 can be easily suppressed.

[0031] As shown in FIG. 5, the pair of slits 11a and 12a have inclined portions 11c and 12c that are inclined with respect to the vertical direction (hereinafter, the inclined portion provided in the first slit 11a is referred to as the "first inclined portion 11c", and the inclined portion provided in the second slit 12a is also referred to as the "second inclined portion 12c"). Normally, the plumb bob 10 is in a state where the suspension load rope 5 is inserted, and the central axes of the cylindrical portions 11 and 12 are arranged parallel to the vertical direction. Therefore, since the pair of slits 11a and 12a each have the inclined portions 11c and 12c, the suspension load rope 5 and each of the slits 11a and 12a can be held non-parallel. As a result, unintentional extraction of the suspension load rope 5 from the pair of cylindrical portions 11 and 12 can be easily suppressed.

[0032] In the present embodiment, the slits 11a and 12a are composed of the inclined portions 11c and 12c. Since the slits 11a and 12a are composed of the inclined portions 11c and 12c, the entire slits 11a and 12a can be kept non-parallel to the suspension load rope 5, and unintentional extraction of the suspension load rope 5 from the pair of cylindrical portions 11 and 12 can be easily suppressed. Further, according to this configuration, when the suspension load rope 5 is inserted, it is easy to insert the suspension load rope 5 for each of the slits 11a and 12a.

[0033] The inclined portions 11c and 12c extend linearly or in a partial spiral shape. The inclination angle of the inclined portions 11c and 12c with respect to the vertical direction may change along the vertical direction or may be constant. The inclined portions 11c and 12c are inclined so that the suspension load rope 5 cannot pass through in a state where the central axes of the cylindrical portions 11 and 12 are arranged in the vertical direction and the suspension load rope 5 extends in the vertical direction.

[0034] It is preferable that the inclination directions of the pair of inclined portions 11c and 12c are opposite to each other. According to this configuration, it is necessary to change the direction of the suspension load rope 5 when inserting and removing it from the first inclined portion 11c and when inserting and removing it from the second inclined portion 12c. Therefore, unintentional extraction of the suspension load rope 5 from the pair of cylindrical portions 11 and 12 can be more easily suppressed.

[0035] The widths of the slits 11a and 12a are equal to or greater than the diameter of the suspension load rope 5. The widths of the slits 11a and 12a are preferably uniform along the vertical direction.

[0036] The widths of the slits 11a and 12a may be uniform in the radial direction of the cylindrical portions 11 and 12 (that is, the thickness direction of the cylindrical portions 11 and 12). On the other hand, the widths of the slits 11a and 12a may gradually decrease from the outer side to the inner side in the radial direction of the cylindrical portions 11 and 12. By the widths of the slits 11a and 12a gradually decreasing from the outer side to the inner side in the radial direction of the cylindrical portions 11 and 12, the weight 10 can facilitate the insertion of the suspension load rope 5 into the cylindrical portions 11 and 12 of the suspension load rope 5 while suppressing the unintentional slipping out of the suspension load rope 5 from the cylindrical portions 11 and 12.

[0037] (Connecting portion) The plurality of connecting portions 13 are arranged at equal angular intervals in the circumferential direction of the pair of cylindrical portions 11 and 12. According to this configuration, it is easy to stabilize the postures of the pair of cylindrical portions 11 and 12. More specifically, it is easy to arrange the pair of cylindrical portions 11 and 12 such that their central axes are parallel to the vertical direction.

[0038] The specific shape of the connecting portion 13 is not particularly limited, and examples include a rod shape, a plate shape, a string shape, a chain shape, etc. (In FIGS. 1 to 5, a rod shape is illustrated.) According to these configurations, it is easy to arrange the pair of cylindrical portions 11 and 12 at intervals in the vertical direction. Note that not all of the connecting portions 13 of the weight 10 need to have the same shape, and for example, a rod-shaped connecting portion and a chain-shaped connecting portion may be used in combination.

[0039] The connecting portion 13 may be detachably provided to at least one of the pair of cylindrical portions 11 and 12. According to this configuration, for example, after inserting the suspension load rope 5 into the pair of slits 11a and 12a, the connecting portion 13 can be connected to the cylindrical portions 11 and 12. Therefore, it is easy to attach and detach the weight 10 to and from the suspension load rope 5.

[0040] (Mounting portion) The attachment portion 14 protrudes radially outward from the outer peripheral surface of the first cylindrical portion 11, for example. The attachment portion 14 has a locking hole 14a connected to the string-like portion 7. Note that the specific shape of the attachment portion 14 is not particularly limited. For example, it may have a protruding portion that protrudes radially outward from the outer peripheral surface of the first cylindrical portion 11 and a locking portion such as a shackle connected to the protruding portion, and may be configured to be connectable to the string-like portion 7 by this locking portion. The pair of attachment portions 14 are preferably arranged at positions facing each other with the center of gravity of the weight 10 therebetween.

[0041] <Advantages> The weight 10 can be inserted into and removed from the inside and outside of the cylindrical portions 11 and 12 through the slits 11a and 12a of the suspension rope 5. Therefore, the weight 10 can be easily attached to and detached from the suspension rope 5. Further, since the weight 10 includes a pair of cylindrical portions 11 and 12 arranged at intervals in the vertical direction, it is easy to prevent the suspension rope 5 from accidentally coming out of the weight 10.

[0042] Since the weight 10 does not have a detachable member (a member for closing the slit) provided in a conventional weight, there is no risk of the detachable member falling. Therefore, the weight 10 can avoid troubles caused by the falling of the detachable member.

[0043] [Second Embodiment] <Weight> The weight 20 in FIGS. 6 and 7 is used for the construction machine 1 in FIG. 1 in place of the weight 10 in FIGS. 4 and 5. The weight 20 includes a pair of cylindrical portions 21 and 22 (the "first cylindrical portion 21" arranged on the upper side and the "second cylindrical portion 22" arranged on the lower side) arranged at intervals in the vertical direction, and a connecting portion 23 connected to the pair of cylindrical portions 21 and 22. The pair of cylindrical portions 21 and 22 are connected by a plurality of connecting portions 23. Further, the weight 20 includes a pair of attachment portions 14 connected to the first cylindrical portion 21 and connected to the string-like portion 7 (see FIGS. 1 to 3). The weight 20 is composed of a pair of cylindrical portions 21 and 22, a plurality of connecting portions 23, and a pair of attachment portions 14. Slits 21a and 22a (the "first slit 21a" provided in the first cylindrical portion 21 and the "second slit 22a" provided in the second cylindrical portion 22) for inserting and removing the suspension rope 5 are formed in the pair of cylindrical portions 21 and 22. Since the configuration of the attachment portion 14 can be the same as that of the attachment portion 14 in FIGS. 3 and 4, the same reference numerals are given and the description thereof is omitted.

[0044] (Cylindrical portion) Of the plurality of connecting portions 23, the pair of cylindrical portions 21 and 22 are detachably provided with at least one connecting portion (hereinafter, the detachable connecting portion is also referred to as a "detachable connecting portion 23a"). Therefore, the pair of cylindrical portions 21 and 22 have first connecting portions 21d and 22d that are detachably connected to the detachable connecting portion 23a. The first connecting portions 21d and 22d are, for example, ring pieces. The first cylindrical portion 21 can have the same configuration as the first cylindrical portion 11 in FIGS. 3 and 4 except for having the first connecting portion 21d. Further, the second cylindrical portion 22 can have the same configuration as the second cylindrical portion 12 in FIGS. 3 and 4 except for having the first connecting portion 22d. Note that, as will be described later, the detachable connecting portion 23a reliably suppresses the suspension rope 5 from coming out of the pair of cylindrical portions 21 and 22. Therefore, the center lines of the pair of slits 21a and 22a may coincide with each other so that the suspension rope 5 can be easily inserted and removed.

[0045] (Connecting portion) The specific configuration of the plurality of connecting parts 23 can be the same as that of the plurality of connecting parts 13 in FIGS. 3 and 4, except that it has a detachable connecting part 23a. (In FIGS. 6 and 7, a configuration in which the connecting part 23 is chain-shaped is illustrated.) Second connecting parts 23b that are detachably connected to the first connecting parts 21d and 22d are provided at both ends of the detachable connecting part 23a. The second connecting part 23b is, for example, a hook having a retaining mechanism.

[0046] The plurality of connecting parts 23 are arranged so as to block the passage of the suspension rope 5 when the suspension rope 5 is inserted into and removed from the pair of slits 21a and 22a.

[0047] The detachable connecting part 23a is arranged between the first slit 21a and the second slit 22a. More specifically, the detachable connecting part 23a is arranged at a position that forms the shortest passage for inserting and removing the suspension rope 5 by being removed from at least one of the cylindrical parts 21 and 22. According to this configuration, when the suspension rope 5 is inserted into and removed from the slits 21a and 22a, as shown in FIG. 7, it is necessary to remove the detachable connecting part 23a from at least one of the cylindrical parts 21 and 22. Therefore, by attaching the detachable connecting part 23a to the pair of cylindrical parts 21 and 22 with the suspension rope 5 inserted into the pair of cylindrical parts 21 and 22, it is possible to easily and surely prevent the suspension rope 5 from unintentionally coming out of the pair of cylindrical parts 21 and 22. Note that the weight 20 may be configured to form a passage for inserting and removing the suspension rope 5 when two or more detachable connecting parts 23a are removed.

[0048] [Advantages] Since the detachable connecting part 23a of the weight 20 is arranged between the pair of slits 21a and 22a, it is possible to easily and surely prevent the suspension rope 5 from unintentionally coming out of the pair of cylindrical parts 21 and 22.

[0049] [Other Embodiments] The above embodiments do not limit the configuration of the present invention. Therefore, based on the description in this specification and common technical knowledge, it is possible to omit, replace, or add components of each part of the above embodiments, and all of them should be construed as belonging to the scope of the present invention.

[0050] For example, as shown in FIG. 8, in a front view seen from a direction perpendicular to the central axis of the cylindrical portions 31 and 32, it is preferable that the end portion 31b of the first slit 31a on the second cylindrical portion 32 side and the end portion 32b of the second slit 32a on the first cylindrical portion 31 side do not face each other in the vertical direction. Since the end portions 31b and 32b do not face each other in the vertical direction, it is possible to easily suppress the unintentional slipping out of the suspension load rope 5. Further, it is preferable that the end portion 31b of the first slit 31a and the end portion 32b of the second slit 32a do not at least partially overlap in the vertical direction, and more preferably, they do not completely overlap.

[0051] Also, as shown in FIG. 8, it is also preferable that the weight 30 is configured to surround the entire circumference of the suspension load rope 5 by portions other than the slits 31a and 32a of the pair of cylindrical portions 31 and 32 in a state where the suspension load rope 5 is inserted. This configuration is preferably adopted particularly in the configuration of the first embodiment in which a plurality of connecting portions 33 are not arranged so as to block the passage of the suspension load rope 5 when inserting and removing the suspension load rope 5. According to this configuration, it is possible to more easily suppress the unintentional slipping out of the suspension load rope 5 from the pair of cylindrical portions 31 and 32.

[0052] The weight can also be configured to have only a single connecting portion as long as the pair of cylindrical portions can be arranged at intervals in the vertical direction.

[0053] The shape of the pair of slits and the arrangement of the pair of slits are not limited to the configuration described in the above embodiment. For example, as described in the second embodiment, if a plurality of connecting portions 33 are arranged to block the passage of the suspension rope 5 when the suspension rope 5 is inserted and removed, the shape and arrangement of the pair of suspension ropes are not limited.

[0054] The plumb bob may have an inclined portion in which only one of the pair of slits is inclined with respect to the vertical direction. Further, the inclined portion may change its inclination direction in the middle, and may be curved as a whole or partially. Furthermore, even when the slit has an inclined portion, the slit does not have to be composed only of the inclined portion. For example, the slit may have a straight portion extending in the vertical direction and an inclined portion connected to the straight portion.

[0055] In the above embodiment, the case where the construction machine is a crane has been described. However, the plumb bob can be used in various devices that need to detect overwinding of the suspension rope.

[0056] As described above, the plumb bob can suppress the unintentional removal of the suspension rope even if it does not have a detachable member for closing the slit. However, the plumb bob is not limited to a configuration without a detachable member.

Industrial Applicability

[0057] The plumb bob according to one aspect of the present invention is suitable for facilitating the assembly of construction machines.

Explanation of Symbols

[0058] 1 Construction machine 2 Lower traveling body 3 Upper slewing body 4 Lifting member 4a Boom 4b Jib 4c Sheave 5 Suspension rope 6 Limit Switch 7 Cord-like Portion 8 Hook 10, 20, 30 Weights 11, 21, 31 First Cylindrical Portion 11a, 21a, 31a First Slit 11b, 31b End Portions 11c First Inclined Portion 12, 22, 32 Second Cylindrical Portion 12a, 22a, 32a Second Slit 12b, 32b End Portions 12c Second Inclined Portion 13, 23, 33 Connection Portion 14 Mounting Portion 14a Locking Hole 21d, 22d First Connection Portion 23a Detachable Connection Portion 23b Second Connection Portion R1 First Virtual Region R2 Second Virtual Region

Claims

1. A plumb bob through which the suspension rope is inserted to detect overwinding of the suspension rope hanging down from the heaving member of a construction machine, a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, wherein slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions, the connecting portion is detachably provided with at least one of the pair of cylindrical portions, and the connecting portion is a plumb bob disposed between the pair of slits provided in the pair of cylindrical portions.

2. A plumb bob through which the suspension rope is inserted to detect overwinding of the suspension rope hanging down from the heaving member of a construction machine, a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, wherein slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions, and the center lines of the pair of slits do not coincide with each other.

3. A plumb bob through which the suspension rope is inserted to detect overwinding of the suspension rope hanging down from the heaving member of a construction machine, a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, wherein slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions, and the center lines of the pair of slits are non-parallel.

4. A plumb bob through which the suspension rope is inserted to detect overwinding of the suspension rope hanging down from the heaving member of a construction machine, a pair of cylindrical portions arranged at intervals in the vertical direction, and a connecting portion connected to the pair of cylindrical portions, wherein slits for inserting and removing the suspension rope are respectively formed in the pair of cylindrical portions, and the pair of slits has inclined portions inclined with respect to the vertical direction.

5. The plumb bob according to claim 4, wherein the inclination directions of the pair of inclined portions provided in the pair of slits are opposite to each other.

6. The plumb bob according to any one of claims 1 to 5, wherein the connecting portion is rod-shaped, plate-shaped, string-shaped or chain-shaped.

7. The plumb bob according to any one of claims 1 to 6, wherein the inner diameter of the upper cylindrical portion of the pair of cylindrical portions is larger than the inner diameter of the lower cylindrical portion.

Images