Hook with safety latch

Abstract

To provide a hook with a latch, which enables simplification of a hooking operation of a wire rope in the hook.SOLUTION: This hook with a latch comprises: a hook body 2 having a base 22 and a tip 23; a main latch 3 pivotally supported at one end on the base 22 and rotatable from a position of abutting at the other end against the inside of the tip 23 to close an opening 24 to a position of being separated inward from the hook body 2 to open the opening 24; a sub-latch 4 pivotally supported on the main latch 3, extending at one end toward the base 22, brought into contact at the other end with the outside or the top of the tip 23, and set at a position of abutting at one end against an inner part 22b of the base 22 and being separated at the other end from the outside of the tip 23; and biasing means 5 for biasing the sub-latch 4 to bias the main latch 3 in a direction to set the closing position. The sub-latch 4 rotates along rotation of the main latch 3. and the sub-latch 4 slides at one end inward along the base 22, and moves away at the other end from the outside of the tip 23.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a hook with a stopper.

Background Art

[0002] Commonly used hooks, such as lower hooks of hoisting machines and sling hooks, have a member for preventing the detachment of wire ropes or the like called an arm-shaped hook latch at the opening of the hook. The hook latch is biased by a spring or the like in the direction of closing the opening of the hook, and prevents the loop (eye) of the wire rope hung on the hook from coming off the hook.

[0003] However, when the suspended load hung from the hook via the wire rope lands while the hook is being lowered, the wire rope becomes unloaded, and the eye rises up inside the hook, and may swing due to twisting, wind or the like. As a result, part of the eye may wrap around the upper outer side of the hook, and the eye may become caught only on the hook latch. If a load is applied to the wire rope again in this state, the hook latch is rotated downward, and the eye may fall off the hook. Such a phenomenon is generally referred to as the "puzzle ring phenomenon" or "back slip-out phenomenon".

[0004] In addition, while the hook is rising with a suspended load, if the tip of the hook comes into contact with an obstacle from below, the hook latch may be pushed down against the spring force. As a result, the ascent of the suspended load stops and the suspended load swings greatly, and the eye may fall out from the gap between the hook and the hook latch. Such a phenomenon is referred to as the "hook tip catching phenomenon".

[0005] Patent Document 1 discloses a hook comprising a main stopper that acts as a hook latch, a secondary stopper rotatably mounted to the main stopper, and a secondary torsion spring that biases the secondary stopper in the direction that the main stopper closes the hook. In such a hook, if the eye twists and rotates to the outside of the hook, a force acts in the direction that pushes the secondary stopper downward, but the secondary stopper does not rotate downward. As a result, the main stopper attached to the secondary stopper does not rotate, and no gap is formed between the main stopper and the hook, thus preventing the eye from falling off the hook. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6350732 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 requires two separate springs: a main torsion spring that biases the main stopper in a direction that closes the opening of the hook body, and a secondary torsion spring that biases the secondary stopper, which is pivotally supported by the main stopper, in a direction that closes the opening of the hook body. Therefore, the cost of the stopper mechanism increases due to the increase in the number of parts and the resulting increase in manufacturing processes.

[0008] Furthermore, the secondary safety catch is bent at a relatively large angle, with the upper side convex, at the pivot axis that is pivotally supported by the main safety catch. As a result, even when the secondary safety catch is pulled up to fully open the opening, it is difficult to secure sufficient clearance between the tip of the hook body and the secondary safety catch. Therefore, when hooking the wire rope between the secondary safety catch and the tip of the hook body, extra movements are required to ensure that the wire rope catches on the inside rather than the outside of the tip, making the hooking process cumbersome.

[0009] Furthermore, the diameter of the wire rope that can be hooked onto the hook body is limited to a smaller diameter compared to a hook body without a safety mechanism, thus reducing the versatility of the hook body.

[0010] Furthermore, in the hook described in Patent Document 1, when the hook is rising with a suspended load attached, if the tip of the hook comes into contact with an obstacle from below, there is a step between the auxiliary safety catch and the tip of the hook, which may cause the suspended load to swing violently.

[0011] This invention has been made in view of the above circumstances, and aims to provide a hook with a safety latch that can simplify the operation of hooking wire ropes and the like onto the hook. [Means for solving the problem]

[0012] The hook with a one-sided locking mechanism of the present invention comprises a hook body having a base and a tip facing the base and forming an opening between the base and the tip; a main latch pivotally supported by the base at one end and rotatable between a closed position in which the other end abuts against the inside of the tip and closes the opening, and an open position in which the latch moves inward from the hook body and opens the opening; and a main latch pivotally supported by the main latch, with one end extending toward the base and the other end abutting against the outside or apex of the tip when the main latch is in the closed position, when the main latch is in the open position. The device comprises a sub-latch, one end of which abuts against the inner part of the base and the other end spaced apart from the outside of the tip, and a biasing means that biases the main latch toward the closed position via a pivot shaft that supports the sub-latch. As the main latch rotates against the biasing force of the biasing means from the closed position to the open position, the sub-latch also rotates about the axis, and one end of the sub-latch slides inward along the base, while the other end of the sub-latch separates from the outside of the tip, opening the opening.

[0013] Furthermore, in the above-described invention, it is preferable that the other end of the main latch has a flange portion that is wide in the width direction of the main latch.

[0014] Further, in the above-described invention, the biasing means is a torsion coil spring, which is wound around a shaft that pivotally supports the sub-latch, and it is preferable that the single torsion coil spring mutually biases one end of the sub-latch and the other end of the main latch.

[0015] Further, in the above-described invention, it is preferable that the sub-latch is pivotally supported on the shaft in a state of sandwiching both left and right sides of the main latch.

[0016] Further, in the above-described invention, the sub-latch is preferably formed from a wire rod.

[0017] Further, in the above-described invention, it is preferable that an engaging portion with which the other end of the sub-latch engages when the main latch is in the closed position is formed on the outer side of the distal end portion. Effects of the Invention

[0018] According to the present invention, it is possible to provide a hook with a come-off preventing member that can simplify the operation of hooking a wire rope or the like onto the hook. Brief Description of the Drawings

[0019] [Figure 1A] FIG. 1A is a side view showing the configuration of the hook with a come-off preventing member according to the present embodiment. [Figure 1B] FIG. 1B is a front view showing the configuration of the hook with a come-off preventing member according to the present embodiment. [Figure 2A] FIG. 2A is a side view showing the configuration of the main latch according to the present embodiment. [Figure 2B] FIG. 2B is a plan view showing the configuration of the main latch according to the present embodiment. [Figure 3A] FIG. 3A is a side view showing the configuration of the sub-latch according to the present embodiment. [Figure 3B] FIG. 3B is a plan view showing the configuration of the sub-latch according to the present embodiment. [Figure 4A] FIG. 4A is a side view showing the configuration of the latch spring according to the present embodiment. [Figure 4B] FIG. 4B is a plan view showing the configuration of the latch spring according to the present embodiment. [Figure 5A] FIG. 5A is a side view showing the configuration of the hook with a stopper according to the present embodiment, showing a state where the main latch is closed. [Figure 5B] FIG. 5B is a side view showing the configuration of the hook with a stopper according to the present embodiment, showing a state where the main latch is partially opened. [Figure 5C] FIG. 5C is a side view showing the configuration of the hook with a stopper according to the present embodiment, showing a state where the main latch is fully opened. [Figure 6] FIG. 6 is a side view showing the configuration of a hook with a stopper according to a modified example. [Mode for Carrying Out the Invention]

[0020] [Present Embodiment] Hereinafter, the hook 1 with a stopper according to the present embodiment will be described with reference to the drawings. To maintain orientation consistency between the drawings, all drawings are marked with arrows representing three mutually perpendicular axes, namely the x-axis, y-axis, and z-axis. "One end" and "the other end" respectively refer to one side and the other side in the x-axis direction, "width direction" refers to the y-axis direction, and "upper" and "lower" respectively refer to the vertically upper side and vertically lower side along the z-axis direction. For ease of understanding, the axial direction is appropriately written together, for example, as "one end in the x-axis direction".

[0021] FIG. 1A is a side view showing the configuration of the hook 1 with a stopper according to the present embodiment. FIG. 1B is a front view showing the configuration of the hook 1 with a stopper according to the present embodiment. The hook 1 with a stopper includes a hook body 2, a main latch 3, a sub-latch 4, and a latch spring 5.

[0022] (Hook Body) The hook body 2 is provided with an eye portion 21 having a hole penetrating in the y-axis direction at an upper part, and a lower part thereof is curved into a hook shape. The eye portion 21 holds the hook body 2 in a suspended state by passing an unillustrated wire rope, wire chain or the like therethrough.

[0023] The hook body 2 may be used, for example, as a lower hook or sling hook for a hoist, or for any other purpose. Furthermore, the material passed through the eye portion 21 and the material suspended by the hook body 2 are not limited to wires, but may also be other sling-like or ring-like materials, and the material of the material passed through is not limited.

[0024] The hook body 2 further includes a base portion 22 and a tip portion 23 that faces the base portion 22 and whose inner surface forms an opening 24 between itself and the base portion 22.

[0025] The base portion 22 refers to the portion of the hook body 2 from the eye portion 21 downwards to the point where the hook body 2 begins to curve. The tip portion 23 is located at the tip of the hook body 2, which curves from the base portion 22, rotates approximately 180 degrees, and extends almost parallel to the base portion 22, facing the base portion 22. As a result, the base portion 22 and the tip portion 23 form an opening 24 for wire ropes 6 and the like to enter and exit the hook body 2. The dimensions of the opening 24 are set to be larger than the maximum diameter of a wire rope that is normally used.

[0026] Furthermore, in the hook body 2, the direction inward from the opening 24 (the direction enclosed by the curved hook body 2) is referred to as the inward direction, and the direction outward from the opening 24 is referred to as the outward direction.

[0027] (Main latch) The main latch 3 is pivotally supported at one end (the base 22 side in the x-axis direction in Figure 1A) by the base 22 through a first bolt 36, and its other end (the tip 23 side in the x-axis direction in Figure 1A) is rotatable between a closed position that closes the opening 24 and an open position that opens the opening 24. The closed position is the position shown in Figure 1A, where the other end of the main latch 3 abuts against the inside of the tip 23 of the hook body 2, closing the opening 24. The open position is where the other end of the main latch 3 rotates away from the inside of the tip 23 of the hook body 2 and abuts against the base 22, opening the opening 24. The open position also includes a state where the main latch 3 is slightly away from the base 22, but rotated enough for a wire rope 6 or the like to pass through.

[0028] Therefore, the main latch 3 cannot rotate in the direction opposite to the open position from the closed position, that is, in the direction in which the other end of the main latch 3 moves away from the inside of the tip portion 23 to the outside of the hook body 2, with the first bolt 36 at one end as the pivot axis, because the other end abuts against the inside of the tip portion 23 of the hook body 2.

[0029] Here, the structure of the main latch 3 will be described with reference to Figures 2A and 2B. Figure 2A is a side view showing the configuration of the main latch 3 according to this embodiment. Figure 2B is a top view showing the configuration of the main latch 3 according to this embodiment.

[0030] The main latch 3 is a flat plate-shaped member that is elongated in the x-axis direction as a whole, and has a first bolt hole 31, a second bolt hole 32, a first notch 33, a second notch 34 as a notch, and a flange portion 35.

[0031] The first bolt hole 31 is located at one end, on the left side of the paper, and is a bolt hole that penetrates in the y-axis direction. The main latch 3 is pivotally supported on the base 22 of the hook body 2 by passing the first bolt 36 through the first bolt hole 31 (Figure 1A).

[0032] The second bolt hole 32 is located near the center of the main latch 3 and, like the first bolt hole 31, is a bolt hole that penetrates in the y-axis direction. The second bolt hole 32 is used to pivotally support the sub-latch 4, which will be described later, with the second bolt 37 (Figure 1A).

[0033] As shown in Figure 2B, the first notch 33 is provided at one end of the main latch 3 and is cut out in a substantially U-shape with the opening facing one end in the x-axis direction. As shown in Figure 1B, the first notch 33 is a space for inserting the pivot portion 221 so that one end of the main latch 3 is pivotally supported by the first bolt 36 to the pivot portion 221. Considering the smooth rotation of the main latch 3, it is preferable that the width of the first notch 33 in the y-axis direction be set to be larger than the thickness of the pivot portion 221 of the hook body 2 that pivotally supports one end of the main latch 3 in the y-axis direction.

[0034] As shown in Figure 2B, the second notch 34 is provided at the other end of the main latch 3 and is cut out in a substantially U-shape with the opening 34a on the other end side in the x-axis direction. As shown in Figure 1A, the second notch 34 is a space for a part of the inside of the tip portion 23 of the hook body 2 to contact the other end of the main latch 3 while gripping it when the other end is in contact with the inside of the tip portion 23 of the hook body 2.

[0035] In the closed position, where the other end of the main latch 3 grips the inside of the tip 23 of the hook body 2, the main latch 3 is restricted from further outward rotation. Therefore, by the other end of the main latch 3 gripping a portion of the tip 23 of the hook body 2, even if the wire rope 6 hooked inside the hook body 2 presses against the main latch 3 in the y-axis direction, the main latch 3 is prevented from shifting in the y-axis direction. Thus, a gap is created between the main latch 3 and the tip 23, making it more reliable to prevent the wire rope 6 from falling out.

[0036] As shown in Figure 2B, the flange portion 35 is provided at the other end of the main latch 3 and is formed so that its width in the y-axis direction is greater than that of other parts of the main latch 3. The y-axis dimension of the flange portion 35 is set to be slightly larger than the y-axis dimension of the hook body 2 (Figure 1B).

[0037] The flange portion 35 is the part where the worker's fingers rest when rotating the main latch 3 inward from the closed position. Therefore, by setting the width of the flange portion 35 in the y-axis direction to be slightly larger than the width of the hook body 2, the worker can rest their fingers on the flange portion 35 without the tip portion 23 of the hook body 2 getting in the way.

[0038] (Sub-latch) The sub-latch 4 is pivotally supported on the second bolt 37 of the main latch 3. When the main latch 3 is in the closed position, one end 4a of the sub-latch 4 abuts against the first inner portion 22a of the base 22, and the other end 4b of the sub-latch 4 abuts against the outside of the tip portion 23. When the main latch 3 is in the open position, one end 4a abuts against the second inner portion 22b of the base 22, which is inward from the first inner portion 22a, and the other end 4b of the sub-latch 4 is positioned away from the outside of the tip portion 23 toward the base 22. Note that when the main latch 3 is in the closed position, one end 4a of the sub-latch 4 may abut near the first bolt hole 31 of the main latch 3 instead of the first inner portion 22a of the base 22, or it may not abut anywhere at all. However, when the main latch 3 is in the closed position, regardless of where one end 4a of the sub latch 4 is located, it is preferable that one end 4a of the sub latch 4 extends toward the base 22 and is located near the first inner portion 22a of the base 22 or in the vicinity of the main latch 3.

[0039] Regardless of the position of the main latch 3 when it is in the closed position, one end 4a of the sub-latch 4 immediately contacts the first inner portion 22a of the base 22 as soon as the main latch 3 begins to rotate from the closed position. In other words, whether the main latch 3 rotates from the closed position to the open position or from the open position to the closed position, one end 4a of the sub-latch 4 slides almost along the inner portion of the base 22, except when the main latch is near the closed position.

[0040] When the main latch 3 rotates from the closed position to the open position, the other end 4b of the sub-latch 4 rotates counterclockwise in the plane of the paper around the second bolt 37. At this time, the other end 4b moves away from the state in which it was in contact with the outside of the tip portion 23 and rises outward toward the base portion 22.

[0041] The structure of the sub-latch 4 will now be described with reference to Figures 3A and 3B. Figure 3A is a side view showing the configuration of the sub-latch 4 according to this embodiment. Figure 3B is a top view showing the configuration of the sub-latch 4 according to this embodiment.

[0042] The sub-latch 4 is made of wire and is formed as a long, narrow rectangular ring in the x-axis direction. The sub-latch 4 has a straight section 41, a wound section 42, and an inclined section 43 from the other end.

[0043] The straight section 41 extends in the longitudinal direction, the x-axis direction, and at the other end, both ends in the y-axis direction are connected in a roughly U-shape (Figure 3B). The straight section 41 extends from the point where the main latch 3 is pivotally supported by the second bolt 37 of the main latch 3 (winding section 42) to the outside of the tip section 23 that abuts against the hook body 2 when the main latch 3 is in the closed position.

[0044] The winding section 42 is the portion where the wire extending from the straight section 41 to one end is wound around the wire towards the end from the center in the x-axis direction to form a loop. The winding section 42 is formed by winding the wire once and is provided on both sides of the width direction of the sub-latch 4, which is the y-axis direction. The winding section 42 has two loops formed by the winding of the wire so as to penetrate through the center in the y-axis direction. The two loops are arranged on both sides of the width direction of the winding section 42 and are pivotally supported on the main latch 3 through the second bolt 37 (Figure 1B). The number of turns wound in the winding section 42 is set to a degree that has sufficient strength to be pivotally supported on the second bolt 37. Increasing the number of turns increases the strength against relative misalignment in the width direction between the sub-latch 4 and the main latch 3, but the width dimension of the sub-latch 4 becomes larger, so in this embodiment, it is described as being wound only once. However, it may be two or more times as long as it does not interfere with the width dimension of the sub-latch 4.

[0045] The inclined section 43 extends in the x-axis direction from the winding section 42 toward one end and is inclined from the straight section 41 with the winding section 42 as the starting point. The inclination angle relative to the straight section 41 is set appropriately along with its length so that the main latch 3 and the sub-latch 4 can rotate in cooperation.

[0046] The inclined section 43 is arranged such that both ends in the y-axis direction are connected in a substantially U-shape at one end (Figure 3B). At one end of the inclined section 43, the wires extending from both ends of the inclined section 43 in the y-axis direction face each other with a gap 44 between them without being connected.

[0047] Since the sub-latch 4 is made of wire, a single wire is processed to form the straight section 41, the wound section 42, and the inclined section 43. The gap 44 is the part where the start and end ends of the wire face each other. This makes it possible to reduce costs compared to forming the sub-latch 4 from a single square ring-shaped member without a gap 44.

[0048] Furthermore, as described above, one end 4a of the sub-latch 4 slides along the inner surface of the base 22 when the main latch 3 rotates. At this time, friction occurs between the one end 4a of the sub-latch 4 and the base 22, but because the wires in the inclined portion 43 of the sub-latch 4 face each other with a gap 44 between them, both wires in the width direction can be elastically deformed with respect to the gap 44. As a result, when the main latch 3 rotates, one end 4a of the sub-latch 4 can slide along the inner surface of the base 22 more smoothly. Therefore, the rotation of the main latch 3 becomes smoother.

[0049] (Latch spring) The latch spring 5, like the sub-latch 4, is pivotally supported on a second bolt 37 inserted through the second bolt hole 32 of the main latch 3. The latch spring 5 constantly biases the sub-latch 4 so that it rotates clockwise in the plane of Figure 1A.

[0050] Since the sub-latch 4 is rotatable independently of the main latch 3, when the sub-latch 4 is biased as described above, the sub-latch 4 receives a biasing force in the direction that the main latch 3 opens, via the second bolt 37, with one end 4a of the sub-latch 4 and the contact portion of the first inner portion 22a as the pivot point. However, since the other end of the main latch 3 is in contact with the inside of the tip portion 23, it cannot rotate any further in the opening direction. As a result, the main latch 3 is fixed in the closed position, closing the opening 24, as shown in Figure 1A, unless an external force is applied.

[0051] The structure of the latch spring 5 will now be described with reference to Figures 4A and 4B. Figure 4A is a side view showing the configuration of the latch spring 5 according to this embodiment. Figure 4B is a top view showing the configuration of the latch spring 5 according to this embodiment.

[0052] The latch spring 5 is a torsion coil spring 5, which serves as a biasing means composed of wire. The torsion coil spring 5 has a coil portion 51, a first arm portion 52, and a second arm portion 53. In this embodiment, a double torsion spring is used, which consists of two torsion coil springs 5 ​​connected in parallel. However, since a double torsion spring is sometimes referred to as a torsion coil spring 5, the terminology will be explained using the broader concept of "torsion coil spring 5".

[0053] The coil section 51 is the part in which the wire is wound to form a coil. The number of turns of the wire is set appropriately according to the required biasing force. Two coil sections 51 are arranged in parallel in the width direction of the torsion coil spring 5, which is the y-axis direction. Therefore, it is preferable that the number of turns is the same between the two coil sections 51 so that there is no bias in the biasing force.

[0054] The first arm 52 has two linear sections that extend from the outside of each of the two coil sections 51 in the y-axis direction toward one end in the x-axis direction. The first arm 52 has a roughly U-shape, connected by linear connecting sections that extend in the y-axis direction from one end of each linear section.

[0055] The second arm portion 53 consists of two linear sections that extend from the inside of each of the two coil portions 51 in the y-axis direction toward the other end in the x-axis direction.

[0056] The latch spring 5 is configured as described above, with the coil portion 51 pivotally supported on the second bolt 37.

[0057] The first arm 52 contacts the lower side of one end of the x-axis inclined portion 43 of the sub-latch 4, biasing that portion upward from downward in the z-axis direction. As a result, the first arm 52 always biases the sub-latch 4 to rotate clockwise around the first bolt 36 as the axis in the plane of Figure 1A.

[0058] The second arm portion 53 is located on the lower z-axis surface of the main latch 3 and abuts between the second bolt hole 32 and the flange portion 35. As a result, the second arm portion 53 biases the main latch 3 in a direction that causes it to rotate counterclockwise around the first bolt 36 as the axis in the plane of Figure 1A.

[0059] [Operation] Next, the operation of the hook 1 with a safety latch will be explained with reference to Figures 5A, 5B, and 5C.

[0060] Figure 5A is a side view showing the configuration of the hook 1 with a safety latch according to this embodiment, showing the main latch 3 in a closed state. Figure 5B is a side view showing the configuration of the hook 1 with a safety latch according to this embodiment, showing the main latch 3 partially open. Figure 5C is a side view showing the configuration of the hook 1 with a safety latch according to this embodiment, showing the main latch 3 fully open.

[0061] In Figure 5A, the main latch 3 is in the completely closed position, and no external force is acting on it. In this state, the main latch 3 is pressed inward by the second arm 53 of the latch spring 5. However, since the second notch 34 of the main latch 3 cannot rotate clockwise in the plane of the paper beyond the tip 23, the opening 24 of the hook body 2 is completely closed.

[0062] The sub-latch 4 has one end of its inclined portion 43 pressed against the inside of the base 22 by the first arm 52 of the latch spring 5. At the same time, the tip of the straight portion 41 of the sub-latch 4, which is an integral member, is pressed against the outside of the tip 23 of the hook body 2. As a result, the biasing force of the latch spring 5 acts in a direction that rotates the main latch 3 counterclockwise in the plane of Figure 5A, via the second bolt 37 of the main latch 3 that pivotally supports the sub-latch 4. Note that while the tip of the straight portion 41 of the sub-latch 4 is pressed against the outside of the tip 23 of the hook body 2, it is not necessarily required that one end of the inclined portion 43 be pressed against the inside of the base 22. That is, until one end of the inclined portion 43 is pressed against the inside of the base 22, the tip of the straight portion 41 of the sub-latch 4 slides along the tip 23 of the hook body 2.

[0063] In Figure 5B, the main latch 3 is in a position between the fully closed position and the fully open position. In Figure 5A, when the flange portion 35 of the main latch 3 is pushed downward by an operator's finger or the like, the main latch 3 rotates clockwise in the plane of the paper against the biasing force of the latch spring 5.

[0064] At this time, the main latch 3 rotates around the first bolt 36, and consequently, the sub-latch 4 also rotates around the second bolt 37 of the main latch 3. The sub-latch 4 slides along the inner surface of the base 22, from a state where one end is pressed against the first inner surface 22a of the base 22 toward the second inner surface 22b.

[0065] In other words, the main latch 3 rotates clockwise while the sub-latch 4 rotates counterclockwise. The main latch 3 and the sub-latch 4 are connected by a second bolt 37 and biased by a latch spring 5, so there is no play in any of the components, and the state shown in Figure 5B is uniquely determined.

[0066] In Figure 5C, the main latch 3 is in the fully open position, and the sub-latch 4 is also fully open. In the state shown in Figure 5B, if the gap between the other end of the straight section 41 of the sub-latch 4 and the tip 23 of the hook body 2 becomes larger than the diameter of the wire rope 6 that is hooked onto the hook body 2, the worker pulls the wire rope 6 into the inside of the hook body 2.

[0067] As a result, even without the worker pressing down on the flange portion 35 of the main latch 3 with their fingers or the like, the wire rope 6 is held between the main latch 3 and the tip portion 23 of the hook body 2, and the rotation angle of the main latch 3 is maintained.

[0068] Subsequently, the worker pulls the wire rope 6 inward into the hook body 2, or the wire rope 6 rotates the main latch 3 clockwise in the plane of Figure 5C due to its own weight. At this time, the sub-latch 4 rotates counterclockwise, similar to the state shown in Figure 5B.

[0069] When the wire rope 6 is no longer in contact with the main latch 3, the main latch 3 rotates due to the biasing force of the latch spring 5, and its other end is pressed inward by the tip portion 23, and the sub-latch 4 rotates due to the biasing force of the latch spring 5 and is pressed against the tip portion 23.

[0070] To summarize the worker's actions, as shown in Figures 5A, 5B, and 5C, the worker first presses down on the flange portion 35 of the main latch 3 with their finger and rotates it clockwise. Next, when the gap between the sub-latch 4 and the tip portion 23 becomes larger than the diameter of the wire rope 6, the worker pulls the wire rope 6 into the hook body 2 through the gap and releases their finger from the flange portion 35.

[0071] Next, the wire rope 6 is pulled into the hook body 2 until the main latch 3 begins to rotate in the direction that returns to the inside of the tip 23 due to the biasing force of the latch spring 5. Depending on the relationship between the weight of the wire rope 6 and the spring constant of the latch spring 5, the final step of pulling the wire rope 6 into the body may be unnecessary.

[0072] Furthermore, when removing the wire rope 6 that is hooked onto the hook body 2, the worker presses down on the flange portion 35 of the main latch 3, as shown in Figures 5A, 5B, and 5C, to move the main latch 3 toward the open position. When the gap between the main latch 3 and the hook body 2 becomes larger than the diameter of the wire rope 6, the worker pulls the wire rope 6 up from the hook body 2 and separates it outward from the tip portion 23.

[0073] Once the worker has pulled up the wire rope 6 until it is positioned between the main latch 3 and the hook body 2, they no longer need to press down on the flange portion 35 of the main latch 3. After the wire rope 6 is clamped between the main latch 3 and the hook body 2, simply pulling up the wire rope 6 will cause the wire rope to detach from the tip portion 23 by passing between the main latch 3 and the hook body 2.

[0074] The operation of the safety latch hook 1, along with the worker's procedure, has been explained above. When the wire rope 6 is pulled into the hook body 2 and the load is suspended via the wire rope 6, the main latch 3 is in the closed position (Figure 5A).

[0075] For example, if the safety hook 1 is used as the lower hook of a hoisting machine (not shown), the lower hook will descend together with the wire rope 6 in the state shown in Figure 5A. When the suspended load lands, the wire rope 6 becomes unloaded, and the eye 61, which is the loop portion of the wire rope 6 that is hooked onto the hook body 2, may rise up within the hook body 2, particularly towards the tip 23.

[0076] The raised eye 61 swings due to twisting of the wire rope 6 or wind, causing a portion of the eye 61 to wrap around to the top of the hook body 2. At this time, near the tip 23, the sub-latch 4 is positioned above the main latch 3, so the eye 61 only catches on the sub-latch 4.

[0077] In this state, when the lower hook rises and load is applied to the wire rope 6 again, a load acts on the sub-latch 4 in a direction that causes it to rotate downward via the eye 61. However, one end 4a of the sub-latch 4 is in contact with the first inner portion 22a of the base portion 22, and the other end is in contact with the outside of the tip portion 23.

[0078] As a result, the sub-latch 4 does not rotate even when subjected to a load, maintaining the state shown in Figure 5A, and the main latch 3 remains in contact with the inside of the tip 23 without rotating. The eye 61, which has wrapped around above the sub-latch 4, slides downward on the sub-latch 4 under the load of the suspended load, moving downward from the tip 23, and the eye 61 returns to its original position (Figure 5A).

[0079] Therefore, even if the eye 61 of the wire rope 6 rises above the hook body 2, a so-called "puzzle phenomenon" occurs, the main latch 3 does not rotate, thus preventing the wire rope 6 from falling off the hook body 2.

[0080] Furthermore, even if the eye 61 curves upward sharply and reaches above the main latch 3 and above the second bolt 37, the sub-latch 4 has one end 4a in contact with the first inner portion 22a of the base 22 and the other end in contact with the outside of the tip portion 23, and is connected to the main latch 3 via the second bolt 37, so the main latch 3 will not rotate downward. When a load is applied again, the eye 61 slides downward via the main latch 3 and sub-latch 4 and returns to the hook body 2 from the tip portion 23. Therefore, regardless of the nature of the "puzzle effect," it is possible to prevent the main latch 3 from rotating and to prevent the wire rope 6 from falling off.

[0081] [Differentiation] In the above embodiment, when the main latch 3 is in the closed position, the sub-latch 4 abuts against the outside of the tip portion 23 of the hook body 2. However, as shown in Figure 6, the shape of the tip portion 23 may be changed to have a bulging portion 23a that further bulges outwards as an engaging portion. In this case, the parts that differ from the above embodiment are the shape of the tip portion 23 and the length of the sub-latch 4. Note that the length of the sub-latch 4 does not necessarily have to be changed depending on the shape of the tip portion 23.

[0082] In the hook body 2 having a bulge 23a at its tip 23, when the main latch 3 is in the closed position, the inner side of the other end of the sub-latch 4 overcomes the bulge 23a downwards and engages with it. As a result, the sub-latch 4 is fixed to the tip 23 without separating from the tip 23, and the main latch 3 is fixed in the closed position, thus more reliably preventing the rotation of the main latch 3 and preventing the wire rope 6 from falling off.

[0083] Furthermore, when the operator presses the main latch 3 to rotate it to the open position, an action is required to disengage the other end of the sub-latch 4 from the bulge 23a.

[0084] In other words, in this modified example, when the worker hooks the wire rope 6 onto the hook body 2, the worker releases the engagement of the sub-latch 4 with the bulging portion 23a and pushes the main latch 3 downward with a finger or the like to rotate it towards the open position, which in turn automatically rotates the sub-latch 4.

[0085] [effect] According to the above embodiments, the following effects are achieved.

[0086] The torsion coil spring 5 biases the sub-latch 4, thereby biasing the main latch 3 towards the closed position via the second bolt 37 that pivotally supports the sub-latch 4. Therefore, it is not necessary to provide separate torsion coil springs 5 ​​for rotating the sub-latch 4 and for biasing the main latch 3. Thus, it is possible to suppress the increase in the cost of the anti-detachment mechanism due to an increase in the number of parts and the resulting increase in manufacturing processes.

[0087] Furthermore, as the main latch 3 rotates against the biasing force of the torsion coil spring 5 from the closed position to the open position, the sub-latch 4 also rotates around the second bolt 37, causing the other end of the sub-latch 4 to move away from the outside of the tip portion 23 and open the opening 24. This allows the main latch 3 and the sub-latch 4 to rotate simultaneously in opposite directions. As a result, when the main latch 3 is opened, a sufficient gap can be secured between the sub-latch 4 and the tip portion 23 of the hook body 2. Therefore, when hooking the wire rope 6 between the sub-latch 4 and the tip portion 23, the wire rope 6 can be easily hooked inside the tip portion 23, preventing the hooking process from becoming complicated.

[0088] Furthermore, as described above, by ensuring a sufficient gap between the sub-latch 4 and the tip portion 23, the diameter of the wire rope 6 that can be hooked onto the hook body 2 is not limited to a smaller diameter compared to a hook without a safety mechanism, thereby preventing a decrease in the versatility of the hook body 2.

[0089] Furthermore, when the main latch 3 is in the closed position and the wire rope 6 is to be hooked onto the hook body 2, the sub-latch 4 rotates upward as the main latch 3 rotates simply by the operator pushing down the flange portion 35 of the main latch 3 from the closed position to the open position. Therefore, of the two components that constitute the hook-prevention mechanism—the main latch 3 and the sub-latch 4 which prevents the main latch 3 from being pushed down by the wire rope 6—the wire rope 6 can be hooked onto the hook body 2 by operating only the main latch 3 without operating the sub-latch 4, thus preventing the hooking operation of the wire rope 6 from becoming complicated.

[0090] Furthermore, since the sub-latch 4 rotates in conjunction with the rotation of the main latch 3 when only the main latch 3 is operated, compared to systems that require the operation of two components, the main latch 3 and the sub-latch 4, operational errors and forgotten operations can be reduced, thereby lessening the burden on the operator.

[0091] Furthermore, when the main latch 3 is in the closed position, the other end of the sub-latch 4 is in contact with the outside of the tip 23 of the hook body 2. Therefore, even if the wire rope 6 hooked to the hook body 2 wraps around to the upper side of the sub-latch 4 due to an unloaded state or other reasons, creating a so-called puzzle-like phenomenon, the sub-latch 4 supports the wire rope 6, preventing the main latch 3 from rotating in the direction of opening.

[0092] Furthermore, because the other end of the sub-latch 4 abuts against the outside of the tip 23 of the hook body 2, there is no step above the sub-latch 4. Therefore, the wire rope 6 that has wrapped around above the sub-latch 4 slides along the sub-latch 4 without contacting the tip 23 and moves downward from the other end of the sub-latch 4. Thus, the wire rope 6 returns to its original position before it twisted, making it possible to more reliably prevent the wire rope 6 from falling off due to the puzzle-like phenomenon.

[0093] Furthermore, since the retaining mechanism that prevents the wire rope 6 from falling off the hook body 2 is simply a main latch 3 pivotally supported on the base 22 of the hook body 2, existing hook latches, which similarly have the latch pivotally supported on the base 22, can be easily replaced with the retaining hook of this embodiment. As a result, since no change in the shape of the hook body 2 or additional processing is required, the retaining hook of this embodiment can be applied to widely used general-purpose products, and the wire rope 6 retaining function can be enhanced at low cost.

[0094] Furthermore, while the hook body 2 is rising with a suspended load, if the tip 23 of the hook body 2 is about to come into contact with an obstacle from below, the obstacle will come into contact with the sub-latch 4 instead of the hook body 2. This prevents the obstacle from sliding on the sub-latch 4, which has no steps, and getting caught on the hook body 2. Therefore, it is possible to prevent the hook body 2 from getting caught on an obstacle and swinging violently.

[0095] Since the main latch 3 has a wide flange portion 35 at its other end in the axial direction, when an operator presses down on the other end of the main latch 3 to hook the wire rope 6 onto the hook body 2, the larger the area on which to place the fingers makes it easier to press down on the main latch 3. This makes the wire rope hooking operation easier. In addition, it prevents the operation from becoming complicated and requiring double work if the fingers slip off the main latch 3 while pressing it and the main latch 3 returns to the closed position.

[0096] Since the main latch 3 and sub-latch 4 are biased by a torsion coil spring 5 wound around the pivot shaft of the sub-latch 4, the torsion coil spring 5 can be housed integrally with the main latch 3 and sub-latch 4. Therefore, the overall structure of the retaining hook 1 can be made simpler and more compact compared to the case where the spring is provided on the outside of the main latch 3 and sub-latch 4. In addition, since the torsion coil spring 5 is a commonly used general-purpose product, the cost of the retaining hook 1 can be reduced.

[0097] Furthermore, since the main latch 3 and the sub-latch 4 are biased by a single torsion coil spring 5, one end of the sub-latch 4 and the other end of the main latch 3 are biased toward each other, the number of parts is reduced, costs are lowered, and the overall structure of the hook 1 with a safety catch can be made even simpler and more compact.

[0098] Since the sub-latch 4 is pivotally supported by the second bolt 37 while sandwiching both the left and right sides of the main latch 3, if the wire rope 6 hangs down above the main latch 3 and sub-latch 4 due to the puzzle-like phenomenon, the load from the wire rope 6 mainly acts on the sub-latch 4, which is located on the outside in the width direction. As a result, the sub-latch 4, whose rotation in the direction that the main latch 3 opens is restricted, does not rotate even when subjected to the load of the wire rope 6, thus more reliably preventing the puzzle-like phenomenon.

[0099] In this embodiment, the sub-latch 4 is positioned further outward in the width direction than the main latch 3. In this embodiment, it is necessary to form a space inside the sub-latch 4 to accommodate the main latch 3. However, since wire material can be molded more freely, it is easier to process, costs can be reduced, and weight can be achieved.

[0100] Furthermore, one end of the sub-latch 4 slides against the inner part of the base 22 of the hook body 2 as the main latch 3 rotates. By forming the sub-latch 4 from wire, the sliding between the sub-latch 4 and the inner part of the base 22 can be improved, reducing friction. As a result, the rotation of the main latch 3 can be made smoother, improving the operator's operability.

[0101] The tip portion 23 of the hook body 2 has a bulge portion 23a that bulges outward from the tip portion 23, and when the main latch 3 is in the closed position, the other end of the sub latch 4 can be engaged with the bulge portion 23a. As a result, even if a puzzle-like phenomenon occurs due to twisting of the wire rope 6, causing the wire rope 6 to come into contact with the flange portion 35 of the main latch 3 and the main latch 3 to be subjected to a force in the opening direction, the upward rotation of the sub latch 4 is restricted, thereby restricting the rotation of the main latch 3 in the opening direction. Therefore, the wire rope 6 can be more reliably prevented from falling off the hook body 2.

[0102] The embodiments described above are all preferred examples of the present invention. The numerical values, components, arrangement positions of components, and connection configurations shown in the embodiments above are examples only and are not intended to limit the present invention. Furthermore, the figures are not necessarily strictly illustrative.

[0103] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0104] For example, in the above embodiment, a flange portion 35 is provided at the other end of the main latch 3 to facilitate the operator pressing the main latch 3, but the flange portion 35 may be omitted if it does not impair the operator's operability.

[0105] Furthermore, in the above embodiment, a torsion coil spring 5 was used as the latch spring 5, but any other type of spring or elastic body other than a spring may be used as long as it exerts a similar biasing force.

[0106] Furthermore, in the above embodiment, the sub-latch 4 is positioned outside the main latch 3, but conversely, the sub-latch 4 may be positioned inside the main latch 3. If the main latch 3 is on the outside, operator operability can be ensured without providing a flange portion 35 at the other end of the main latch 3.

[0107] Furthermore, although the sub-latch 4 is constructed from wire in the above embodiment, it is not limited to this, and the sub-latch 4 may be formed by forging, casting, press working, or the like.

[0108] Furthermore, although the sub-latch 4 is formed in the shape of a square ring in the above embodiment, it may be composed of multiple members instead of being ring-shaped.

[0109] Furthermore, in the above modified example, the bulging portion 23a is configured as a bulging part of the tip portion 23, but a projection or notch may be provided on the outside of the tip portion 23 so that the sub-latch 4 can engage.

[0110] Furthermore, a cylindrical member that is rotatable relative to the connecting portion of the first arm 52 of the sub-latch 4 may be attached to the connecting portion. [Explanation of Symbols]

[0111] 1. Hook with safety latch 2 Hook body 3 Main latch 4 Sub-latches 5. Torsion coil spring (biasing means) 22 Base 22a First inner section 22b Second inner part (inner part) 23 Tip 23a Swelling part (engaging part) 24 openings 24a aperture 34. Second notch 35 Flange section 37. Second bolt (shaft) 44 Gap

Claims

1. A hook body having a base and a tip that faces the base and forms an opening between it and the base, A main latch, one end of which is pivotally supported by the base and the other end which abuts against the inside of the tip portion to close the opening, and which is rotatable from a closed position to an open position where it moves inward from the hook body to open the opening, A sub-latch is pivotally supported by the main latch, and when the main latch is in the closed position, one end extends toward the base and the other end abuts against the outside or apex of the tip, and when the main latch is in the open position, one end abuts against the inside of the base and the other end is spaced apart from the outside of the tip, A biasing means that biases the sub-latch, thereby biasing the main latch in the direction of the closed position via the shaft that pivots the sub-latch, Equipped with, As the main latch rotates from the closed position to the open position against the biasing force of the biasing means, the sub-latch also rotates around the axis, and one end of the sub-latch slides inward along the base while the other end of the sub-latch separates from the outside of the tip, opening the opening. A hook with a safety latch that features the following characteristics.

2. In the hook with a safety catch according to claim 1, The other end of the main latch has a wide flange portion in the width direction of the main latch. A hook with a safety latch that features the following characteristics.

3. In the hook with a safety catch according to claim 1, The biasing means is a torsion coil spring, which is wound around the shaft that pivotally supports the sub-latch. A single torsion coil spring biases one end of the sub-latch and the other end of the main latch toward each other. A hook with a safety latch that features the following characteristics.

4. In the hook with a safety catch according to claim 1, The sub-latch is pivotally supported on the shaft while sandwiching both the left and right sides of the main latch. A hook with a safety latch that features the following characteristics.

5. In the hook with a safety catch according to claim 1, The aforementioned sub-latch is formed from wire. A hook with a safety latch that features the following characteristics.

6. In the hook with a safety catch according to claim 1, An engagement portion is formed on the outer side of the tip portion, which engages with the other end of the sub-latch when the main latch is in the closed position. A hook with a safety latch that features the following characteristics.

Images