Hanging equipment

Abstract

The present invention provides a lifting device that can securely hold the arm in an open position and can be stored and transported in a compact state when not in use. [Solution] The device comprises a shaft portion 2 to which an eye nut 10 is attached, a base plate 3 attached to the lower end of the shaft portion 2, a slider 4 slidably provided on the shaft portion 2 between the base plate 3 and the eye nut 10, a plurality of arms 5 having an L-shape consisting of an intermediate bent portion 5a, an upper arm portion 5b, and a lower arm portion 5c with a hook portion 5d formed thereon, the bent portion being rotatably attached to the base plate, a plurality of link bars 6 whose lower ends are rotatably connected to the upper arm portion 5b of the arms 5 and whose upper ends are rotatably connected to the slider 4, and a stopper 7 whose upper end is rotatably connected to the slider 4 and whose lower end has a contact surface 7b that abuts against the base plate 3, preventing the slider 4 from descending and closing the lower arm portion 5c of the arms 5.

Description

[[Technical Field]]

[0001] The present invention relates to a sling attached to a hook of a cargo handling machine such as a crane for lifting and conveying heavy objects. [[Background Art]]

[0002] In the work of loading and unloading heavy objects using a sling, the following operations are repeatedly performed: moving the heavy object to a loading position with the arm that grips the heavy object opened, moving the heavy object to an unloading position with the arm closed and the heavy object gripped, and opening the arm to lower the heavy object. It is necessary to lock the arm in an open state before gripping the heavy object, keep the arm closed from when the heavy object is gripped until it is lowered, and open the arm when lowering the heavy object.

[0003] Patent Document 1 discloses a tong device comprising: a pair of first arms whose upper ends are pin-supported by a first shaft support portion; and a pair of second arms whose upper ends are pin-supported by the lower ends of the first arms and whose intermediate portions cross each other at a second shaft support portion, wherein one of the pair of second arms constitutes a bifurcated branch arm. In the tong device, a connecting plate portion is formed on the branch arm, and an engaging member is provided on the other of the pair of second arms. When the tong device is lowered and a heavy object is seated, the engaging member engages with the connecting plate portion to automatically lock the tong device in an expanded state. However, in Cited Document 1, since the engaging portion of the engaging member slides along the inclined surface of the connecting member and engages with the lower end edge of the connecting plate portion, there is a problem that the engagement between the engaging member and the connecting plate portion is easily disengaged.

[0004] Patent Document 2 discloses a sling that moves a passive body up and down by adjusting the pressure applied to a cylinder, and opens and closes a hook member via a pulling member. However, Patent Document 2 requires a pressure source and a control device, which causes the problems of increased device size and complicated system.

[0005] Conventional slings have the problems that they occupy a large installation area when the arm is open, and are prone to tipping over when the arm is closed. [[Prior Art Documents]] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7300790 specification [Patent Document 2] Japanese Patent Publication No. 2005-104727 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the aforementioned conventional problems, and aims to provide a lifting device that can reliably hold an arm in an open position. It also aims to provide a lifting device that can be stored and transported in a compact state when not in use. [Means for solving the problem]

[0008] To solve the aforementioned problems, the present invention provides A shaft portion having a threaded portion formed thereon, with an eye nut attached to the upper end of the threaded portion, A base plate attached to the lower end of the shaft portion, A slider is slidably provided on the shaft portion between the base plate and the eye nut, Multiple arms are rotatably mounted to the base plate, with the bent portion having an L-shape consisting of an intermediate bent portion, an upper arm portion extending upward from the bent portion, and a lower arm portion extending downward from the bent portion, longer than the upper arm portion, and having a hook portion formed at its lower end, and the convex side of the bent portion facing the base plate. Multiple link bars, the lower end of which is rotatably connected to the upper arm portion of the arm, and the upper end of which is rotatably connected to the slider, The device is characterized by comprising a stopper whose upper end is rotatably connected to the slider, and whose lower end has a contact surface formed that contacts the base plate, thereby preventing the slider from descending and closing the lower arm portion of the arm. Since the contact surface at the lower end of the stopper makes full contact with the base plate, it will not come off the base plate and can securely hold the arm when it is extended.

[0009] The contact surface of the stopper is preferably located on the side toward the shaft portion than the perpendicular line passing through the rotation center of the stopper. When the contact surface of the stopper contacts the base plate, since the contact surface is on the side facing the shaft, a moment acts around the pivot point of the stopper, preventing the stopper from coming off the base plate and ensuring that the arm is securely held open.

[0010] Preferably, the stopper has a weight portion on the side opposite to the shaft portion, and the center of gravity of the stopper, including the weight portion, is located outside the longitudinal center line of the stopper. By simply adding a weight to the stopper, the center of gravity of the stopper can be easily positioned outside the longitudinal centerline of the stopper, and the contact surface of the stopper can be positioned on the side toward the axis that is perpendicular to the rotation center of the stopper.

[0011] The system further comprises a collar externally fitted to the shaft portion between the base plate and the slider, When the slider contacts the collar, it is preferable that the hook portion of the lower arm has a contact edge portion that is parallel to the mounting surface. This allows the arm to stand upright on the mounting surface when closed, enabling compact storage and transport when not in use.

[0012] Preferably, the system further includes a lock nut screwed onto the threaded portion between the slider and the eye nut, and the lock nut is provided with a handle. By adjusting the position of the lock nut, the degree to which the slider rises and the arm opens can be adjusted to suit the weight of the object being lifted. [Effects of the Invention]

[0013] According to the present invention, the arm can be reliably held in an open position. Furthermore, according to the present invention, when not in use, it can be stored and transported in a compact state. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [Figure 1] A front view of the sling according to the first embodiment of the present invention. [Figure 2] A plan view of the sling of Figure 1. [Figure 3] A bottom view of the sling of Figure 1. [Figure 4] A rear view of the sling of Figure 1. [Figure 5] A left side view of the sling of Figure 1. [Figure 6] A right side view of the sling of Figure 1. [Figure 7] A longitudinal sectional view of the sling of Figure 1. [Figure 8] A front view of the sling showing a state where an arm is opened. [Figure 9] A front view of the sling showing a state where an arm is closed and a heavy object is gripped. [Figure 10] A front view of the sling showing a state where an arm is closed and a heavy object is lowered. [Figure 11] (a) A partially enlarged front view of Figure 10 showing a state when a stopper is tilted, and (b) an enlarged view showing the direction of a force acting on the stopper. [Figure 12] A front view of the sling showing a state during storage. [Figure 13] A front view of the sling according to the second embodiment of the present invention. [Figure 14] A partially enlarged view of Figure 12 sequentially showing the operation of a stopper. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0016] Figure 1 shows a sling 1 according to the first embodiment of the present invention. The sling 1 includes a shaft portion 2, a base plate 3, a slider 4, an arm 5, a link bar 6, a stopper 7, a lock nut 8, and a collar 9.

[0017] The shaft portion 2 has an upper threaded portion 2a formed on its upper half, and a lower threaded portion 2b with a smaller diameter than the upper threaded portion 2a formed on its lower half. An eye nut 10 is attached to the upper end of the upper threaded portion 2a. The eye nut 10 is used to attach hooks of material handling machinery such as cranes.

[0018] As shown in Figure 7, the base plate 3 is attached by a fixing nut 11 with the lower threaded portion 2b of the shaft portion 2 passing through its center. As shown in Figures 2 and 3, protrusions 3a are formed at equally spaced positions around the base plate 3, and grooves 3b for attaching the arms 5 are formed radially on each protrusion 3a.

[0019] The slider 4 has a cylindrical shape and, as shown in Figure 7, is slidably fitted onto the shaft portion 2 between the base plate 3 and the eye nut 10 via a linear bush 12. Three first projections 13 for attaching the link bar 6 are radially mounted at equally spaced positions on the outer surface of the slider 4. A second projection 14 for attaching the stopper 7 is mounted between two adjacent projections 13.

[0020] The arm 5 consists of three parts. As shown in Figure 7, each arm 5 has an L-shape consisting of an intermediate bent portion 5a, an upper arm portion 5b extending upward from the bent portion 5a, and a lower arm portion 5c extending downward from the bent portion 5a and longer than the upper arm portion 5b. A hook portion 5d is formed at the lower end of the lower arm portion 5c. The arm 5 is rotatably mounted by a support shaft 15, with the bent portion 5a inserted into the groove 3b of the projection 3a of the base plate 3, so that the convex side of the bent portion 5a faces the base plate 3. The hook portion 5d is bent in an L-shape at the lower end of the lower arm portion 5c, and a grounding edge portion 16 is formed at the lower end, which is parallel to the mounting surface when the arm 5 is closed.

[0021] The link bar 6 consists of three sets, each set comprising two elongated plates. The two link bars 6 in each set are rotatably connected by a lower pin 17, with their lower ends sandwiching the upper end of the upper arm portion 5b of the arm 5 from both sides, and their upper ends sandwiching the first projection 13 of the slider 4 from both sides, with an upper pin 18.

[0022] The stopper 7 is a rod-shaped structure with a rectangular cross-section and has a U-shaped mounting portion 7a at its upper end. The mounting portion 7a of the stopper 7 is rotatably connected to the second projection 14 of the slider 4 by a pivot shaft 19. Therefore, the pivot center of the stopper 7 is eccentric from the shaft portion 2. The lower end of the stopper 7 has a contact surface 7b that abuts against the upper surface of the base plate 3 when the stopper 7 hangs down under its own weight, preventing the slider 4 from descending and closing the lower arm portion 5c of the arm 5. The length of the stopper 7 is predetermined so that when the lower end of the stopper 7 abuts against the upper surface of the base plate 3, it opens wider than the outer shape of the heavy object that the arm 5 lifts. In this embodiment, the cross-sectional shape of the stopper 7 is rectangular, but it may be square, circular, elliptical, etc. As shown in Figure 7, the width W in the rotational direction of the stopper 7 is preferably 15-20% of the length L from the pivot shaft 19 to the lower end. If the width W is less than 15%, it becomes unstable, and if it is greater than 20%, it becomes difficult to detach the stopper 7 from the base plate 3.

[0023] The lock nut 8 is screwed onto the upper threaded portion 2a of the shaft 2 between the slider 4 and the eye nut 10. The lock nut 8 is provided with two handles 20 located 180° apart.

[0024] The collar 9 is externally fitted onto the shaft 2 between the base plate 3 and the slider 4. When the slider 4 descends and the arm 5 closes, the lower surface of the slider 4 abuts against the upper end of the collar 9, limiting the descent of the slider 4 and preventing the arm 5 from closing more than necessary.

[0025] Next, with reference to Figures 8 to 12, the operation of the lifting device 1 of the above embodiment when lifting and lowering a heavy object W will be described. Note that in Figures 8 to 12, for the sake of simplifying the drawings, the three arms 5 are shown with two arms 5 positioned 180° apart.

[0026] As shown in Figure 8, a hook from a crane or the like is attached to the eye nut 10 on the shaft portion 2 of the lifting device 1, and the lifting device 1 is suspended. The stopper 7 hangs down due to its own weight, and the contact surface 7c of its lower end comes into contact with the upper surface of the base plate 3. In this state, the upper arm portion 5b of the arm 5 is pulled by the link bar 6, so the lower arm portion 5c opens. Here, by adjusting the position of the lock nut 8, the degree to which the slider 4 rises and the lower arm portion 5c of the arm 5 opens can be adjusted to match the outer diameter of the heavy object W. In this state, the lifting device 1 is moved to the lifting position of the heavy object W and lowered to a position where it can grasp the heavy object W.

[0027] Next, the lower part of the stopper 7 is flicked to the right, as indicated by arrow P in Figure 8, to separate the lower end of the stopper 7 from the base plate 3. As shown in Figure 9, the slider 4 descends under its own weight, and the link bar 6 pushes the upper arm portion 5b of the arm 5 downwards. As a result, the lower arm portion 5c of the arm 5 moves in the closing direction, as indicated by the arrow, and grasps the heavy object W. The stopper 7 remains tilted and contacts the edge of the base plate 3.

[0028] In this state, the heavy object W, grasped by the lifting device 1, is lifted and moved to the unloading position. When it reaches above the unloading position, the heavy object W grasped by the lifting device 1 is lowered. Even after the heavy object W is placed on the platform, as the lifting device 1 is lowered, as shown in Figure 10, the lower arm portion 5c of the arm 5 comes into contact with the periphery of the heavy object W, and the arm 5 is spread apart. As a result, the upper arm portion 5b of the arm 5 pushes up the link bar 6, causing the slider 4 to rise and increasing the distance between the slider 4 and the base plate 3. Consequently, the stopper 7, which was tilted and in contact with the edge of the base plate 3, hangs down above the base plate 3 under its own weight.

[0029] When the lifting device 1 is raised, the slider 4 descends under its own weight, and the contact surface 7c of the lower end of the stopper 7 comes into contact with the upper surface of the base plate 3. At the same time, the link bar 6 pushes the upper arm portion 5b of the arm 5 downward, causing the lower arm portion 5c of the arm 5 to move in the closing direction and return to the state shown in Figure 8, allowing the operation of lifting the next heavy object W to be repeated.

[0030] Furthermore, when the contact surface 7c at the lower end of the stopper 7 contacts the upper surface of the base plate 3, if the stopper 7 is tilted outward as shown in Figure 11, the reaction force F received by the contact surface 7b of the stopper 7 from the base plate 3 is decomposed into a component Fr toward the support shaft 19 and a component Fc toward the shaft portion 2. As a result, a moment M about the support shaft 19 acts on the stopper 7 due to the component Fc toward the shaft portion 2. This prevents the stopper 7 from coming off the base plate 3 and securely holds the arm 5 in the open position.

[0031] In this way, the contact surface 7b at the lower end of the stopper 7 makes contact with the base plate 3 over a wide area, so it does not come off the base plate 3 and can securely hold the arm 5 when it is opened.

[0032] Figure 12 shows the state in which the lifting device 1 is stored in a designated location or loaded onto a truck bed for transport when not in use. When the eye nut 10 is lifted with the stopper 7 separated from the base plate 3, the slider 4 descends under its own weight. The link bar 6 pushes the upper arm portion 5b of the arm 5, causing the lower arm portion 5c of the arm 5 to move in the closing direction. When the slider 4 contacts the upper end of the collar 9 and stops, the lower arm portion 5c stops moving further in the closing direction, allowing the contact edge 16 of the hook portion 5d to rest on the ground and become self-supporting.

[0033] In this way, since arm 5 can stand upright on the ground when closed, it can be stored and transported in a compact state when not in use.

[0034] Figure 13 shows a suspension device 1' according to a second embodiment of the present invention. This suspension device 1' is substantially identical to the suspension device 1 of the first embodiment, except for the shape of the stopper 7, so corresponding parts are denoted by the same reference numerals and their description is omitted.

[0035] The stopper 7 has a rod-shaped lever 21 screwed into the side opposite the shaft 2, serving as a weight. As shown in Figure 13(b), the lower end of the stopper 7 has a contact surface 7b that is parallel to the base plate 3 when the stopper 7, including the lever 21, is supported by the support shaft 19 and hangs down under its own weight. In addition, a rounded corner 7c is formed at the lower end of the stopper 7 on the shaft 2 side to prevent damage to both the collar 9 and the stopper 7 when they come into contact, and to facilitate the removal of the stopper 7 from the base plate 3. The lever 21 of the stopper 7 can be used as a handle when separating the stopper 7 from the base plate 3.

[0036] Because the lever 21 is attached to the stopper 7, the center of gravity G of the combined part of the stopper 7 and lever 21 is located outside the longitudinal centerline of the stopper 7, that is, in the opposite direction to the direction toward the support shaft 2. Preferably, the center of gravity G is located outside the outer surface 7d of the stopper 7. Furthermore, when the upper end of the stopper 7 is rotatably supported by the support shaft 19 on the slider 4 and the lower end hangs down under its own weight, as shown in Figure 13(b), the contact surface 7b of the lower end is located inside the perpendicular line S passing through the support shaft 19, which is the rotation center of the stopper 7, that is, on the side toward the support shaft 2.

[0037] In this way, by simply providing the lever 21 as a weight on the stopper 7, the center of gravity of the stopper 7 can be easily positioned outside the longitudinal centerline of the stopper 7, and the contact surface 7b of the stopper 7 can be positioned on the side toward the shaft 2 relative to the perpendicular S passing through the rotation center of the stopper 7.

[0038] As shown in Figure 14(a), when the slider 4 rises from a state where the stopper 7 is in contact with the edge of the base plate 3, as shown in Figure 14(b), the stopper 7 moves toward the shaft portion 2, and when the stopper 7, including the lever 21, is supported by the support shaft 19 and hangs down under its own weight, the stopper 7 tilts toward the shaft portion 2. Subsequently, when the slider 4 descends, as shown in Figure 14(c), the contact surface 7b at the lower end of the stopper 7 comes into contact with the base plate 3 and locks into place. Here, the reaction force F that the contact surface 7b of the stopper 7 receives from the base plate 3 is decomposed into a component Fr toward the support shaft 19 and a component Fc toward the shaft portion 2. Therefore, a moment M about the support shaft 19 acts on the stopper 7 due to the component Fc toward the shaft portion 2. As a result, the stopper 7 can be securely held open without the stopper 7 coming off the base plate 3.

[0039] The present invention is not limited to the embodiments described above, and various changes and modifications can be made. For example, the lever 21, which is the weight portion of the stopper 7, is not limited to a rod shape and can be made into any shape. [Explanation of Symbols]

[0040] 1…Lifting equipment 2... Shaft 2a... Upper threaded portion 2b...Lower threaded section 3…base board 3a…Protrusion 3b…Groove 4...Slider 5... Arm 5a...Bending part 5b... Upper arm section 5c... Lower arm section 5d…Hook part 6… Link bar 7... Stopper 7a…Mounting part 7b…Abutting surface 7c…roundness 7d…Outer surface 8... Lock nuts 9...Color 10… Eye nut 11…Fixing nut 12…Linear bushing 13…First projection 14…Second projectile 15...Spindle 16...Grounding edge 17...Lower pin 18…Top pin 19...Spindle 20... Handle 21... Lever (weight part)

Claims

1. A shaft portion having a threaded portion formed thereon, with an eye nut attached to the upper end of the threaded portion, A base plate attached to the lower end of the shaft portion, A slider is slidably provided on the shaft portion between the base plate and the eye nut, Multiple arms are provided, each having an L-shape consisting of an intermediate bent portion, an upper arm portion extending upward from the bent portion, and a lower arm portion extending downward from the bent portion, longer than the upper arm portion, and having a hook portion formed at its lower end, with the bent portion rotatably attached to the base plate such that the convex side of the bent portion faces the base plate, Multiple link bars, the lower end of which is rotatably connected to the upper arm portion of the arm, and the upper end of which is rotatably connected to the slider, A lifting device characterized by comprising: a stopper whose upper end is rotatably connected to the slider, and whose lower end has a contact surface formed to contact the base plate, thereby preventing the slider from descending and closing the lower arm portion of the arm.

2. The suspension device according to claim 1, characterized in that the contact surface of the stopper is located on the side toward the shaft portion than the perpendicular line passing through the rotation center of the stopper.

3. The lifting device according to claim 1, characterized in that the stopper has a weight portion provided on the side opposite to the shaft portion, and the center of gravity of the stopper including the weight portion is located outside the longitudinal center line of the stopper.

4. The system further comprises a collar externally fitted to the shaft portion between the base plate and the slider, The suspension device according to claim 1, characterized in that when the slider contacts the collar, a grounding edge parallel to the mounting surface is formed on the hook portion of the lower arm.

5. The lifting device according to claim 1, further comprising a lock nut screwed onto the threaded portion between the slider and the eye nut, wherein a handle is provided on the lock nut.

Images