Overspeed detecting device

Abstract

To provide an overwinding detection device capable of preventing the occurrence of trouble caused by sagging of a wire for a weight by suppressing the sagging of the wire for the weight in overwinding.SOLUTION: An overwind detection device 100 for a hoisting wire 12 that suspends a hoisted load via a hoisted load support unit 2 includes a ring-shaped weight 110 through which the hoisting wire 12 passes, a weight wire 120 that suspends the weight 110, an overwind detection unit 130 that detects push-up of the weight 110 by the hoisted load support unit 2 when the hoisting wire 12 is overwound, and an intermediate fixing member 140 fixed to an intermediate portion of the weight wire 120, wherein the intermediate fixing member 140 integrally includes a ring portion 141 through which the hoisting wire 12 passes and a fixing portion 142 fixed to the intermediate portion of the weight wire 120.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an overwind detection device. [Background technology]

[0002] Patent Document 1 discloses an overwinding detection device (overwinding prevention device) that is applied to a crane and detects overwinding of a hoisting wire. A widely known overwinding detection device is a weight-type overwinding detection device that includes a ring-shaped weight through which the hoisting wire passes, a weight wire that suspends the weight, and an overwinding detection unit that detects the weight being pushed up by the load support unit when the hoisting wire is overwinded.

[0003] Since there is a time lag between the detection of overwinding by the overwinding detector and the stopping of the load support part, in cranes with fast hoisting speeds, it is necessary to quickly detect the approach of the load support part to the overwinding area. In such cases, the general solution is to lengthen the weight wire 202 so that the position of the weight 201 is lowered, as shown in Figure 8(a). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 63-197294 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the weight wire 202 is made longer, the weight wire 202 will sag more when it is overwound, and as shown in Figure 8(b), there is a risk that the slack weight wire 202 will hang down and get caught on a protrusion 204 of the load support part 203. If the crane operator lowers the load support part 203 without noticing that the weight wire 202 has been caught, there is a possibility that the overwinding detection part (for example, a limit switch) will be pulled by the weight wire 202 and may be damaged or fall. Therefore, an object of the present disclosure is to provide an overwinding detection device that can suppress sagging of the weight wire during overwinding and prevent problems caused by sagging of the weight wire. [Means for solving the problem]

[0006] In one aspect, the following solution is provided.

[0007] An overwinding detection device for a hoisting wire that suspends a load via a load support part, a ring-shaped weight through which the winding wire passes; a weight wire for suspending the weight; an overwinding detection unit that detects the lifting of the weight by the load support unit when the hoisting wire is overwound; an intermediate fixing member fixed to an intermediate portion of the weight wire, The intermediate fixing member is a ring portion through which the winding wire passes; and a fixing portion fixed to the middle portion of the weight wire. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to suppress the sagging of the weight wire during overwinding, and to prevent problems caused by the sagging of the weight wire. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall view of a crane to which an over-hoisting detection device according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is a perspective view of the main part of the crane showing the over-hoisting detection device in normal operation. [Figure 3] FIG. 2 is an exploded perspective view of the overwinding detection device. [Figure 4] FIG. [Figure 5]1A and 1B are diagrams showing the structure of the overwinding detection unit, in which FIG. 1A shows the overwinding detection unit under normal conditions, and FIG. 1B shows the overwinding detection unit under overwinding conditions. [Figure 6] FIG. [Figure 7] FIG. 1 is a perspective view of a main part of a crane showing an over-hoisting detection device when an over-hoisting occurs. [Figure 8] 1A and 1B are perspective views of the essential parts of a crane showing an over-hoisting detection device according to a conventional example, where FIG. 1A shows the device in normal operation and FIG. 1B shows the device in over-hoisting operation. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Furthermore, in the drawings, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0011] [crane] FIG. 1 is an overall view of a crane 1 to which an over-hoisting detection device 100 according to an embodiment of the present invention is applied.

[0012] As shown in Figure 1, the crane 1 of this embodiment is an example of a crane to which the over-hoisting detection device 100 is applied, and is a fixed tower crane installed at a building construction site or the like. The crane 1 includes a mast 4 fixed to a foundation 3 and extending in the vertical direction, a rotating body 5 supported rotatably on the upper part of the mast 4, a jib 6 supported on the rotating body 5 so that it can be raised and lowered, and a load support part 2 suspended from the tip of the jib 6. The mast 4 may also be fixed to the building.

[0013] The rotating body 5 is rotatably supported on the upper part of the mast 4 via a rotating device (not shown). The rotating body 5 is rotatable about an axis extending in the vertical direction. The rotating body 5 may also be supported on the mast 4 so as to be movable up and down in the vertical direction.

[0014] The rotating body 5 is provided with a hoisting winch 8 that enables the jib 6 to be raised and lowered, a lifting winch 9 that enables the load support part 2 to be raised and lowered, and a support frame 10 that stands upright from the rotating body 5.

[0015] A hoisting wire 11 is wound around the hoisting winch 8. The hoisting wire 11 extends from the hoisting winch 8 via a support frame 10 to the jib 6 and is connected to the tip of the jib 6. By driving the hoisting winch 8, the hoisting wire 11 is wound up or let out, allowing the jib 6 to be hoisted with the base end side as a fulcrum.

[0016] A hoisting wire 12 is wound around the lifting winch 9. The hoisting wire 12 extends downward from the tip of the jib 6 from the lifting winch 9, via the support frame 10 and the tip of the jib 6. A load support part 2 is connected to the tip of the hoisting wire 12. By driving the lifting winch 9, the hoisting wire 12 is wound up or let out, allowing the load support part 2 to move up and down in the vertical direction. The load support part 2 is not particularly limited as long as it is capable of supporting a load, and may be, for example, a hook block or a bucket.

[0017] [Overwinding detection device] FIG. 2 is a perspective view of the main part of the crane 1 showing the over-hoisting detection device 100 in normal operation.

[0018] As shown in Fig. 1, the overwinding detection device 100 is provided at the tip of the jib 6 and detects overwinding of the hoisting wire 12 (excessive rise of the load support part 2). As shown in Figs. 1 and 2, the overwinding detection device 100 includes a weight 110, a weight wire 120, an overwinding detection part 130 (see Fig. 5), and an intermediate fixing member 140.

[0019] FIG. 3 is an exploded perspective view of the overwinding detector 100, and FIG. 4 is an exploded perspective view of the weight 100. As shown in FIG.

[0020] 2 to 4, the weight 110 is a ring-shaped weight member having a hollow portion 111, and is installed with the hoisting wire 12 passing through the hollow portion 111. The weight 110 of this embodiment is made up of a pair of half weight members 110a that are divided into semicircular shapes in a plan view, and the pair of half weight members 110a are connected to each other via a plurality of bolts 112 and nuts 113 to form the weight 110. This makes it easy to install the weight 110 relative to the hoisting wire 12.

[0021] The weight wires 120 extend downward from the tip of the jib 6 and suspend the weight 110 connected to the tip. It is desirable to have a plurality of weight wires 120 in order to stably suspend the weight 110. In this embodiment, the weight 110 is suspended by two weight wires 120. The weight wires 120 may extend diagonally downward from the tip of the jib 6 as shown in FIG. 1, or may extend directly downward from the tip of the jib 6 as shown in FIG. 2.

[0022] 5A and 5B are diagrams showing the structure of the overwinding detection unit 130, in which (a) shows the overwinding detection unit 130 in normal operation, and (b) shows the overwinding detection unit 130 in overwinding.

[0023] The overwinding detection unit 130 detects the lifting of the weight 110 by the load support unit 2 when the hoisting wire 12 is overwound. The overwinding detection unit 130 shown in FIG. 5 is a plunger-type limit switch, and is installed between one of the weight wires 120 and the jib 6. The plunger-type limit switch includes a push switch 131 that is turned ON when pushed, a plunger 132 that pushes in the push switch 131, and a case 133 that houses the push switch 131 and the plunger 132.

[0024] Push switch 131 is maintained in the OFF state by the biasing force of spring 131a, and is switched to the ON state in response to a pushing operation of plunger 132 against the biasing force of spring 131a. Plunger 132 is supported at the bottom end of case 133 so as to be slidable in the vertical direction, and pushes in push switch 131 by the biasing force of spring 132a.

[0025] As shown in Figure 5(a), when the weight 110 is connected to the lower end of the plunger 132 via the weight wire 120, the weight of the weight 110 moves the plunger 132 to a lower position, and the push switch 131 turns OFF. Furthermore, when the load support part 2 pushes up the weight 110 due to over-winding of the hoisting wire 12, the plunger 132 moves to an upper position due to the biasing force of the spring 132a in accordance with the slack in the weight wire 120, as shown in Figure 5(b). This turns ON the push switch 131, making it possible to detect over-winding of the hoisting wire 12.

[0026] 2 and 3, the intermediate fixing member 140 is fixed to the intermediate portion of the weight wire 120. The intermediate fixing member 140 integrally includes a ring portion 141 through which the hoisting wire 12 passes, and a plurality of fixing portions 142 fixed to the intermediate portion of the weight wire 120.

[0027] FIG. 6 is an exploded perspective view of the intermediate fixing member 140. As shown in FIG.

[0028] As shown in Figures 3 and 6, the intermediate fixing member 140 of this embodiment is composed of a pair of half intermediate fixing members 140a, each having a ring portion 141a and a fixing portion 142a that are split in half, and the intermediate fixing member 140 is formed by connecting the pair of half intermediate fixing members 140a together.

[0029] The pair of half intermediate fixing members 140a are connected to each other via a plurality of bolts 143 and nuts 144 when the intermediate fixing members 140 are attached to the weight wire 120. That is, when the pair of half intermediate fixing members 140a are connected to each other, the ring portion 141 surrounds the hoisting wire 12, and the fixing portion 142 sandwiches the weight wire 120. This makes it possible to easily install the intermediate fixing member 140 to an existing overwinding detection device 100. Note that the connecting means of the half intermediate fixing members 140a is not limited to the bolts 143 and nuts 144. For example, the bolt insertion hole formed in one half intermediate fixing member 140a may be a female thread, and the nut 144 may be omitted. Furthermore, the bolt 143 may be a cap bolt, and the bolt insertion hole may be formed with a counterbore to accommodate the bolt head of the cap bolt.

[0030] FIG. 7 is a perspective view of the main part of the crane 1, showing the overwinding detection device 100 when an overwind occurs.

[0031] As shown in Figure 7, when the hoisting wire 12 is overwound, the load support unit 2 pushes up the weight 110. When the weight wire 120 slackens as the load support unit 2 pushes up the weight 110, the overwinding detection unit 130 turns ON and detects the overwinding. When the overwinding detection unit 130 detects the overwinding, it stops winding the hoisting wire 12 manually or automatically, but depending on the time difference between the detection of the overwinding and the stop of winding, the distance the load support unit 2 pushes up the weight 110 may become large. At this time, the intermediate fixing member 140, as shown in Figure 5, engages with the hoisting wire 12 and remains in a position above the weight 110 while supporting the middle part of the weight wire 120, thereby restricting the drooping length of the slack weight wire 120. This reduces the possibility that the hanging weight wire 120 will get caught on the protrusion 21 of the load support part 2, and prevents problems caused by the hanging weight wire 120 from occurring.

[0032] [Second Example] Next, an overwinding detection device 100 according to a second embodiment will be described. However, for configurations common to the above-described embodiment, the same reference numerals as those in the above-described embodiment will be used, and the description of the above-described embodiment may be used.

[0033] Although not shown in the drawings, the overwinding detector 100 of the second embodiment differs from the above-described embodiments in that it includes a plurality of intermediate fixing members 140, which are fixed at predetermined intervals in the vertical direction to the middle portion of the weight wire 120. According to the overwinding detector 100 of the second embodiment, the length by which the weight wire 120 sags during overwinding can be further reduced, making it possible to more reliably prevent problems caused by the weight wire 120 sagging.

[0034] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of components of the above-described embodiments.

[0035] For example, in the above-described embodiment, a tower crane is used as an example of a crane, but a crawler crane or a crawler crane can also be used. [Explanation of symbols]

[0036] 1 crane 2 Hanging load support part 21 Protrusions 3 Basics 4 Mast 5 Rotating body 6 Jib 8. Drilling winch 9 Lifting winch 10 Support Frame 11. Drilling wire 12 Winding wire 100 Overwinding detection device 110 Weight 110a Half weight member 111 Hollow part 112 volts 113 Nut 120 Weight wire 130 Overwinding detector 131 Push switch 131a Spring 132 Plunger 132a Spring 133 cases 140 Intermediate fixing member 140a Half-split intermediate fixing member (half-split member) 141, 141a Ring section 142, 142a Fixed part 143 volts 144 Nut 201 Weight 202 Weight wire 203 Hanging load support section 204 Protrusions

Claims

1. An overwinding detection device for a hoisting wire that suspends a load via a load support part, a ring-shaped weight through which the winding wire passes; a weight wire for suspending the weight; an overwinding detection unit that detects the lifting of the weight by the load support unit when the hoisting wire is overwound; an intermediate fixing member fixed to an intermediate portion of the weight wire, The intermediate fixing member is a ring portion through which the winding wire passes; and a fixing portion fixed to an intermediate portion of the weight wire.

2. a plurality of the intermediate fixing members; 2. The overwinding detector according to claim 1, wherein the plurality of intermediate fixing members are fixed to an intermediate portion of the weight wire at predetermined intervals in the vertical direction.

3. the intermediate fixing member is configured by a pair of half members having the ring portion and the fixing portion, which are split in half, 3. The overwinding detector according to claim 1, wherein when the pair of half members are connected to each other, the ring portion surrounds the hoisting wire and the fixing portion sandwiches the weight wire.

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