JP2546821Y2 - Mobile crane winding prevention device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding prevention device used for a mobile crane.

[0002]

2. Description of the Related Art As shown in FIG. 4, a mobile crane is provided with a hook block pulley 7 having a wire rope 2 from a hydraulic drive winch 1 arranged on a tip pulley 5 of a telescopic boom 3 tip 4 and a hook block 6. The hook block 6 is hung up and down freely at the tip of the boom 3 by hanging around. The boom 3 is attached to a swivel (not shown) which is mounted on a vehicle frame (not shown) so as to be able to be driven to swing. , The swivel or the boom 3 at the base end.

In this type of mobile crane, the crane work is performed by driving the boom 3 (turning drive, raising / lowering drive, extension / contraction drive), and raising and lowering the hook block 6 by the hydraulic drive winch 1. When the hook block 6 is driven to wind up, there is a risk that the hook block 6 collides with the structure of the end portion 4 of the boom 3 and an excessive force acts on the end portion 4 of the boom 3 and the wire rope 2. A safety device called is installed.

As shown in FIG. 5, the winding prevention device includes a winding detection switch 8 for detecting that the hook block 6 has approached the structure of the end portion 4 of the boom 3 below a predetermined value. The winding stop switch 9 and the winding stop means 9 are connected so as to generate an operation signal to the winding stop means 9 when the winding detection switch 8 detects the winding detection switch 8. And an electric circuit 11 having a manually operated stop release means 10 for interrupting the relevant connection. In the example of FIG. 5, the winding detection switch 8 is attached to the boom tip 4 and its operating member has a rope 8.
The closed state is maintained by the weight 8b suspended through the hook block 7a, and the weight 8b is configured to be shut off when the weight 8b is engaged with the upper end of the hook block 7 and lifted. The switch 8 is not limited to this type, and may be a direct-acting switch, for example, defined in Article 25 of the mobile crane structure standard. Winding stop means 9
Is composed of a solenoid-operated unload valve that unloads pressure oil in a high-pressure oil passage 1d that connects a four-way three-position switching valve 1b for driving control of a hydraulic motor 1a of a hydraulic drive winch 1 and a pump 1c. Have been. The unload valve 9 serving as a hoisting stop means is configured as a normally closed type that operates when the solenoid 9a is energized to be in an unloaded state, and is de-energized and is deactivated to be in an on-load state.

The electric circuit 11 connects a relay 11a interposed in an electric circuit 13 connecting the power supply 12 (+ terminal) and the winding detection switch 8, and connects the power supply 12 (+ terminal) to the solenoid 9a of the unload valve 9. A relay switch 11b of the b-contact type of the relay 11a interposed in the electric circuit 14, and a stop release means 10 interposed in series with the relay switch 11b in the electric circuit 14.

[0006] The operation of the conventional winding prevention device configured as described above will be described. During a normal crane operation, the suspension distance of the hook block 6 with respect to the structure of the end portion 4 of the boom 3 is large, and the winding detection switch 8 does not detect the winding state. In this state, the winding detection switch 8 is closed, the relay 11a of the electric circuit 11 is energized, and the relay switch 11b of the relay 11a is shut off. Therefore, the unload valve 9 as a winding stop means is provided.
Does not operate, and keeps the on-load state, so that the hydraulic drive winch 1 can freely perform the hoisting and lowering drive. When the hook block 6 approaches the structure of the end portion 4 of the boom 3 to a predetermined value or less (in this example, 25 cm or less) by the lifting drive of the hydraulic drive winch 1, the winding detection switch 8 turns the hook block 6. The winding is detected and shut off. Then, energization of the relay 11a of the electric circuit 11 is cut off, the relay switch 11b of the relay 11a is closed, and an operation signal is generated from the electric circuit 11 to the unload valve 9 to the solenoid 9a of the unload valve 9. Energized). As a result, unload valve 9
Actuates (unloads) and the hydraulic drive winch 1 cannot be driven. Therefore a situation where the hook block 6 is damaged the structure or a wire rope 2 collides with the structure of the boom 3 tip is to be prevented in advance.

Further, the mobile crane travels with the boom 3 down, down, down and at a predetermined turning position. In traveling, however, the hook block 6 is prevented from swinging. The block 6 is driven to wind up beyond the winding area (the hook block 6 is further driven to wind up after the winding detection switch 8 detects the winding state) so that the hook block 6 approaches or closes to the structure of the tip 4 of the boom 3. You need to make contact. Further, a so-called auxiliary jib is provided at the tip of the boom 3 so as to be able to adjust the elevation. The auxiliary jib is driven by lifting and lowering the hook block 6 with the hook block 6 abutting against the tip of the auxiliary jib. In this case, the hook block 6 is wound up beyond the winding range (the hook block 6 is further wound up after the winding detection switch 8 detects the winding state), and the hook block 6 is driven up and down. The block 6 needs to be close to or contact with the structure of the end 4 of the boom 3. In this case, the stop release means 10 of the electric circuit 11 is shut off.
Then, the connection between the winding detection switch 8 and the unloading valve 9 serving as a winding stop means by the electric circuit 11 is cut off.
Even if the winding detection switch 8 detects the winding state, the unload valve 9 does not operate (unload). Therefore, the hook block 6 can be made to approach or come into contact with the structure of the end portion 4 of the boom 3.

[0008]

In the above-mentioned conventional apparatus for preventing winding of a mobile crane, the connection between the winding detecting switch 8 and the winding stop means 9 by the electric circuit 11, that is, the winding is detected when the winding detecting switch 8 is detected. Stopping means 9
Since the related connection for generating an operation signal (unload signal) can be cut off even when the winding detection switch 8 is in a non-detection state (a state where the winding of the hook block 6 is not detected), for example, If the hydraulic drive winch 1 is lifted from the non-detection state of the winding detection switch 8 with the release operation (shutoff operation) of the stop release means 10 erroneously, even if the winding detection switch 8 is subsequently detected, the hook block The winding motion of 6 does not stop. In this case, the operator cannot recognize that the winding detection switch 8 is in the detection state, and often causes the hook block 6 to unintentionally collide with the structure of the end portion 4 of the boom 3,
Damage to the boom 3 tip 4 or the wire rope 2
There was something. Such a situation often occurs because the release operation (cutoff operation) of the stop release means 10 is sometimes performed by a part of the crane operator's body unconsciously touching the stop release means 10 or the like. For this reason, the conventional winding prevention device is incomplete. An object of the present invention is to provide a new mobile crane over-wrap prevention device that solves the above-mentioned problems of the conventional mobile crane over-wrap prevention device.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a mobile crane overwind prevention device according to the present invention detects that a hook block has approached a structure at the end of a boom below a predetermined value. A winding-over detection switch 8, winding-up stop means 9 for disabling at least the hydraulic drive winch when the winding-up operation is performed, and a winding-up detection switch for generating an operation signal to the winding-up stop means when the winding detection switch is detected. And an electric circuit 11 having a manually operated stop release means 10 for connecting the winding stop means and disconnecting the relevant connection, wherein the electric circuit 11 is connected to the winding detection switch 8. Only when the winding state is detected and the winding stop means 9 is operating, the winding detection switch by the electric circuit 11 and the winding stop means 9 The relevant connections stop cancellation means 10
It was configured to be able to shut off.

[0010]

According to the winding prevention device for a mobile crane according to the present invention having the above-described configuration, the hydraulically driven winch is operated by accidentally releasing the stop release means 10 from the non-detection state of the winding detection switch 8 (interrupting operation). 1, the electric circuit 11 in which the winding detection switch 8 and the winding stop means 9 are connected so as to generate an operation signal to the winding stop means 9 when the winding detection switch 8 detects Since the related connection is not interrupted, when the winding detection switch 8 detects the winding state, the winding stop means 9 is operated and the winding movement of the hook block 6 becomes impossible. Only in this state, that is, in the state where the winding detection switch 8 detects the winding state, by operating the stop release means 10, the related connection of the electric circuit 11 is cut off and the winding drive of the hydraulic drive winch 1 is performed. It can be made possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The winding prevention device of the mobile crane according to the present invention is different from the above-described conventional winding prevention device only in the configuration of the stop release means 10 interposed in the electric circuit 11. The description of the conventional winding detection device shown in FIGS.

(First Embodiment) In FIG. 1, reference numeral 20 denotes a stop release means in the present invention.
Indicated by. The stop release means 20 includes a relay 21, a relay 22, and a b-contact type relay switch 2 of the relay 21.
1b, a-contact type relay switch 22 of the relay 22
a, a normally open stop release manual switch 23 and a diode 24. The relay switch 21
b is interposed in the electric circuit 14 in series with the relay switch 11b. The diode 24, the stop release manual switch 23, and the relay 21 are interposed in series in an electric circuit 25 connecting the electric circuit 14 downstream of the relay switch 21b and the ground. The relay 22 is provided between the rear stage of the manual switch 23 for releasing the stop of the electric circuit 25 and the ground.
Is interposed. The electric circuit 25 connecting the power supply 12 and the electric circuit 25 between the diode 24 and the stop release manual switch 23 includes the relay switch 22a and the diode 27.
Is interposed.

When the stop release manual switch 23 is not operated, the relay 21 and 22 are not energized when the stop release manual switch 23 is not operated, so that the relay switch 21b is closed, and The related connection between the winding detection switch 8 and the winding stop means 9 by the circuit 11 (related connection for generating an operation signal to the winding stopping means 9 when the winding detection switch 8 is detected) is maintained. Accordingly, the hook block 6 is wound up while the stop release manual switch 23 is being operated (closed operation), and the hook block 6 is in a winding state. When the winding detection switch 8 detects this, the winding stop means 9 Is supplied to the motor to operate (unload) the hoisting / stopping means 9. However, in this embodiment, since the relay 21 and 22 are energized from the electric circuit 25 through the stop release manual switch 23 in the closed state at the same time as the supply of the operation signal (energization) to the winding stop means 9, the relay switch 21 b Is cut off, the operation signal to the winding stop means 9 is released, and the relay switch 22a is released.
Is closed to ensure that power is supplied to the preceding stage of the stop release manual switch 23. Therefore, the winding motion of the hook block 6 is started again, but at least when the winding detection switch 8 is detected during the winding, the hook block 6 is temporarily stopped.
This stops the hoisting motion of the cranes, so that the crane operator can be alerted. In the case of this embodiment, it is preferable that the relay switch 21b be provided with an off-delay function so that the connection of the relay switch 22a is delayed from being turned off. 28 is the relay switch 2 in the electric circuit 26.
This is an alarm placed between the latter stage of 2a and the ground. The alarm 28 is for giving an alarm when the stop release manual switch 23 is closed after the hook block 6 is stopped in the winding state. The alarm 27 may, of course, be arranged between the stage after the stop release switch 23 and the ground.

(Second Embodiment) In FIG. 2, a reference numeral 30 denotes a stop release means in the present invention.
Indicated by. The stop release means 30 comprises a relay 31, a relay contact 31b of the b contact type of the relay 31, and a normally open stop release manual switch 32.
The relay switch 31b is interposed in the electric circuit 14 in series with the relay switch 11b. The relay 31 and the stop release manual switch 32 are interposed in series between the rear stage of the relay switch 11b in the electric circuit 14 and the ground. The relay 31 and the relay switch 31b are configured to shut off the relay switch 31b with a certain time delay in energizing the relay 31. That is, the relay switch 31b has an off-delay function.

When the stop release manual switch 32 is not operated, the relay 31 is not energized when the stop release manual switch 32 is not operated, so that the relay switch 31b is closed and the electric circuit 11 The connection between the winding detection switch 8 and the winding stop means 9 (the connection that generates an operation signal to the winding stop means 9 when the winding detection switch 8 is detected) is maintained. Accordingly, the hook block 6 is wound up while the stop release manual switch 32 is being operated (closed operation), and the hook block 6 is in a winding state, and the winding detection switch 8
When this is detected, an operation signal (energization) is supplied to the winding stop means 9 to operate (unload) the winding stop means 9. However, in this embodiment, since the relay 31 is energized through the manual switch 32 for releasing the closed state simultaneously with the supply of the operation signal (energization) to the winding stop means 9, the relay switch 31b is slightly delayed. Closing means 9
Energization of the actuation signal is ensured. Therefore, as in the first embodiment, the hoisting motion of the hook block 6 is started again. However, the hoisting motion of the hook block 6 stops at least when the winding detection switch 8 is detected during the hoisting. It can alert you. Reference numeral 33 denotes an alarm device disposed between the rear stage of the stop release manual switch 32 and the ground. After the hook block 6 is stopped in the winding state, the alarm 33 is operated by the manual switch 32 for stop release.
Is to be warned when the closing operation is performed.

(Third Embodiment) In the first and second embodiments, the stop release means 20
Alternatively, when the winding switch 8 is operated before the detection of the winding switch 8 (the manual switch 23 or 32 for releasing the stop is closed), the winding of the hook block 6 is performed once when the winding detection of the winding detection switch 8 is detected. Is stopped and the lifting operation is performed again after the crane operator is alerted. However, when the stop release means is operated before the detection point of the winding detection switch 8, the winding detection switch 8 is turned on. It may be arranged such that when the winding state is detected, the hoisting motion of the hook block 6 is stopped and maintained, and the stop is first released by operating the stop releasing means 20 again. An embodiment of such a winding prevention device will be described with reference to FIG.

In FIG. 3, the stop release means is indicated by reference numeral 40. The stop release means 40 includes a relay 41, a relay 42, a relay 43, a relay contact 41 b of the b contact type of the relay 41, and a relay switch 4 of an a contact type of the relay 41.
1a, a b-contact type relay switch 42b of the relay 42,
The relay 43 includes a contact switch type relay switch 43b and a normally-open type manual release switch 44. The relay switch 43b is interposed in the electric circuit 14 in series with the relay switch 11b. The relay 41 and the relay switch 42b are interposed in series between the rear stage of the relay switch 11b in the electric circuit 14 and the ground. Relay 42 and relay switch 41
“b” is connected in series between the stop release manual switch 44 connected to the + terminal of the power supply 12 and the ground. The relay 43 and the relay switch 41a are connected in series between the rear stage of the stop release manual switch 44 and the ground. The circuit configuration thus configured of the stop release means 40 is configured such that after the relay switch 11b connected at the time of detection of the winding detection switch 8 is connected, the interruption of the relay switch 43b of the b-contact type interposed in the electric circuit 14 is connected. This can be performed only when the stop release manual switch 44 is operated (connected). Such a circuit configuration has a relay switch (relay switch 4) to be controlled only when the operation order of the two switches (the winding detection switch 8 and the stop release manual switch 44) is operated in a predetermined order.
3b) is already being used in various fields as a so-called priority circuit.

The stop release means 40 constructed in this way is operated only when the stop release manual switch 44 is operated (close operation) after the winding detection switch 8 detects the winding state of the hook block 6. 11, the connection between the winding detection switch 8 and the winding stop means 9 (the connection which generates an operation signal to the winding stopping means 9 when the winding detection switch 8 is detected) is cut off. If the operation of the stop release manual switch 44 and the detection of the winding state of the winding detection switch 8 are performed in another order, the above-described related connection of the electric circuit 11 is maintained without being interrupted. In the third embodiment, when the hook block 6 is driven to wind up and the winding detection switch 8 detects the winding state of the hook block 6, the manual release switch 4 is turned on.
Regardless of the presence or absence of the operation of 4, the hoisting stop means 9 always operates, the hoisting motion of the hook block 6 stops, and the stopped state is maintained. When the stop is to be released by the stop release means 40, the stop release manual switch 44 may be operated again. Also in this case, the hoisting motion of the hook block 6 stops when the winding detection switch 8 is detected, so that the crane operator can be alerted. In addition, reference numeral 45 denotes an alarm device disposed between the rear stage of the relay switch 41a and the ground. The alarm 45 gives an alarm when the stop release manual switch 44 is closed after the hook block 6 stops in the winding state.

[0019]

The winding prevention device of the mobile crane according to the present invention constructed and operated as described above operates the stop releasing means 10 only when the winding detection switch 8 detects the winding state. This allows the hydraulic drive winch 1 to be driven up by cutting off the related connection of the electric circuit 11, so that when the hook block 6 is in the winding state, the hydraulic drive winch always moves up. Since the stop (temporary stop or continuous stop) is performed, the problem of the conventional winding prevention device described at the beginning is solved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a device for preventing winding of a mobile crane according to the present invention.

FIG. 2 is an explanatory view of a main part of another embodiment of the device for preventing winding of the mobile crane according to the present invention.

FIG. 3 is an explanatory view of a main part of still another embodiment of the apparatus for preventing winding of the mobile crane according to the present invention.

FIG. 4 is an explanatory view of a conventional mobile crane.

FIG. 5 is an explanatory view of a conventional device for preventing winding of a mobile crane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic drive winch 2 Wire rope 3 Boom 4 Tip 5 Tip pulley 6 Hook block 7 Hook block pulley 8 Winding detection switch 9 Winding stop means 20, 30, 40 Stop release means

Claims (1)

(57) [Scope of request for utility model registration] 1. A hook block is wound around a tip of a boom by hanging a wire rope from a hydraulic drive winch between a tip pulley at a boom tip and a hook block pulley arranged on a hook block. An apparatus for preventing winding of a mobile crane, comprising:
A winding detection switch that detects that the block has approached the structure at the boom tip below a predetermined value, a winding stop means that disables at least the hydraulic drive winch when operating, and a winding stop switch that detects when the winding detection switch is detected. An electric circuit comprising a manually operated stop release means for connecting the winding detection switch and the winding stop means so as to generate an operation signal to the winding stop means and for cutting off the connection In the electric circuit, only when the winding detection switch detects the winding state and the winding stop means is operating, the electric circuit is connected to the winding detection switch and the winding stop means by the release means. A device for preventing winding of a mobile crane, characterized in that the device is configured to be able to be shut off by a crane.