JPH0595984U - Winding prevention device for lifting equipment of mobile crane - Google Patents

Abstract

(57) [Abstract] [Purpose] In the conventional wind-up prevention device, the distance between the hoisting tool and the boom tip at the stop position is such that the hoisting tool is used even when the hoisting tool is hoisting and driving at the maximum speed. It is set to a distance that gives the team enough time to stop before a collision. Therefore, the distance between the hoisting gear and the boom tip at the stop position is large, and the working range of the crane is limited accordingly. The present invention provides a wind-up prevention device capable of increasing the working range by ensuring a sufficient time to stop the suspending tool before the collision, and further, reducing the distance between the suspending tool and the boom tip at the stop position. To do. [Structure] A hydraulic drive winch 3 is added to the conventional winding prevention device.
Speed regulation means 9 for regulating the driving speed of the vehicle to a predetermined value or less
And a speed regulation switch 10 for detecting a position where the distance between the suspension 5 and the tip of the boom 1 is longer than the alarm position, and the drive speed regulation means 9 is detected by the detection result of the speed regulation switch 10. Configured to operate.

Description

[Detailed description of the device]

[0001]

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

[0002]

2. Description of the Related Art As shown in FIG. 2, a mobile crane comprises a swing base (not shown) mounted on a vehicle for swiveling, and a boom 1 which is mounted up and down. A suspension 5 is suspended from the tip of the boom 1 via a wire rope 4 from a hydraulic drive winch 3 pulled out via a sheave 2 at the tip. The hydraulic drive winch 3 has its drive speed and drive direction controlled by a drive control device 6 including a four-way three-position hydraulic control valve 6a.

In this type of mobile crane, a hoisting prevention device is attached to prevent the hoisting tool 5 from being hoisted and driven to collide with the tip of the boom 1. The conventional roll-over prevention device is arranged at the tip of the boom 1 and detects the stop switch 7 when the suspension 5 comes close to the tip of the boom 1 and a detection result of the stop switch 7. It is equipped with a winding stopping means 8 which operates at The stop switch 7 is attached to the tip of the boom 1, but in FIG. 2, the stop switch 7 is not arranged at the tip of the boom 1, and the hanger 5 is wound in the electric circuit. It is shown as a switch 7 which is lifted and cut off when it reaches the stop position. The structure of attaching the stop switch 7 to the tip of the boom 1 is well known. The hoisting stopping means 8 is interposed between the pump oil passage 6b of the hydraulic pressure switching valve 6a in the hydraulic control device 6 and the tank in FIG. 2, and unloads the amount of hydraulic oil flowing through the pump oil passage 6b during its operation. It is shown as an unloading valve. The distance between the lifting tool 5 and the tip of the boom 1 at the stop position is detected by the stop switch 7 under the condition that the hydraulic drive winch 3 is driven to wind at the highest speed (the lifting tool 5 is driven at the highest speed). As a result, the stopping of the hoisting motion of the hydraulically driven winch 3 by the hoisting stopping means 8 is set to a distance with a sufficient time margin before the lifting tool 5 collides with the tip of the boom 1. There is.

In the conventional wind-up prevention device configured as described above, the distance between the hoisting tool 5 and the tip of the boom 1 at the stop position is such that the hydraulic drive winch 3 is hoisted and driven at the highest speed (the hoisting tool 5 is the highest). Since it is set assuming that it is being driven by hoisting at a speed), the size will increase and the work range of the mobile crane will be limited accordingly.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention provides a stopping position while securing a time margin necessary for stopping the hoisting motion of the lifting device 5 before the lifting device 5 collides with the tip of the boom 1. An attempt is made to provide a wind-up prevention device capable of expanding the working range of a mobile crane by setting a small distance between the lifting tool 5 and the tip of the boom 1 in the above.

[0006]

[Means for Solving the Problems] In order to achieve the above object, a roll-over prevention device for a mobile crane according to the present invention is configured as follows. A winding used for a mobile crane in which a suspender 5 is suspended from the tip of the boom 1 via a wire rope 4 from a hydraulically driven winch 3 pulled out through a sheave 2 at the tip of the boom 1. An over-prevention device, which is arranged at the tip of the boom 1 and detects when the suspending tool 5 comes to a stop position approaching the tip of the boom 1, and a stop switch 7 that operates based on the detection result of the stop switch 7. In the device provided with the hoisting stopping means 8, a drive speed control means for restricting the drive speed of the winch 3 to a predetermined value or less at the time of its operation is attached to the drive control device 6 of the hydraulic drive winch 3, and the boom 1 A speed regulation switch, which is arranged at the tip and detects a position where the distance between the suspension 5 and the tip of the boom 1 is farther than the stop position, is attached, and the drive is detected by the detection result of the speed regulation switch. A rollover prevention device for a mobile crane, characterized in that it is configured to actuate a dynamic speed regulation means.

[0007]

In the hoisting stop device for a mobile crane of the present invention configured as described above, the drive speed of the hydraulic drive winch 3 is increased when the distance between the hoisting tool 5 and the tip of the boom 1 is farther than the stop position. Since it is restricted to the maximum speed or less, even if the working range of the mobile crane is expanded by setting the distance between the lifting device 5 and the tip of the boom 1 at the stop position smaller than the conventional one, Therefore, it is possible to secure a time margin necessary for stopping the hoisting motion before the lifting device 5 collides with the tip of the boom 1.

[0008]

Embodiment An embodiment of the present invention will be described below with reference to FIG. The roll-up prevention device for a mobile crane according to the present invention is obtained by partially adding a structure to the roll-up prevention device for a conventional mobile crane. The reference numerals used in the description of the device and the description thereof are used as they are in the following description.

In FIG. 1, reference numeral 9 is a throttle valve that is interposed in the pump oil passage 6b of the hydraulic pressure switching valve 6a in the hydraulic control device 6 and limits the amount of working oil flowing through the pump oil passage 6b during its operation. The throttle valve 9 corresponds to the speed regulating means in the scope of claims for utility model registration. When the throttle valve 9 is operated, the drive speed of the hydraulic drive winch 3 is regulated to a predetermined value or less. In other words, the maximum drive speed of the hydraulic drive winch 3 becomes smaller. Reference numeral 10 denotes a speed regulating switch which is arranged at the tip of the boom 1 and detects a position where the distance between the lifting tool 5 and the tip of the boom 1 is longer than the stop position (detection position of the stop switch 7). The speed regulation switch 10 is configured to suspend a weight 10c on its operating arm 10a via a rope 10b, detect when the weight 10c is lifted by a hanging tool 5, and close the weight. . The speed regulation switch 10 is electrically connected to the speed regulation means 9 so that the speed regulation means (throttle valve) 9 operates according to the detection result.

In this embodiment, an example in which the drive speed control means 9 is composed of a solenoid operated throttle valve is shown, but the speed control means 9 may be replaced by, for example, the following. Of course. The adjustment range of the engine rotation speed by the accelerator mechanism of the engine (not shown) that drives the hydraulic pump 6c (the hydraulic pump that supplies hydraulic oil to the hydraulic switching valve 6a via the pump oil passage 6b) is set to the predetermined rotation speed. Those regulated below. In the case where the hydraulic control valve 6a is composed of an electromagnetic proportional control valve, the operation amount of the electromagnetic proportional control valve is set to a predetermined value by limiting the upper limit of the electric signal required for operation for operating the electromagnetic proportional control valve. Those regulated below.

With the hoisting prevention device for a mobile crane of the present invention configured as described above, when the hoisting tool 5 is hoisted and driven, the distance between the hoisting tool 5 and the tip of the boom 1 is at a position farther than the stop position. The speed regulation switch 10 detects this, and the drive speed regulation means 9 operates based on this detection result to regulate the drive speed of the hydraulic drive winch 3 to the maximum speed or less, so that the hoisting stop means 8 operates. Then, the hoisting speed of the hanger 5 does not reach the normal maximum speed. Therefore, even if the working range of the mobile crane is expanded by setting the distance between the hoisting tool 5 at the stop position and the tip of the boom 1 smaller than that of the conventional one, the hoisting motion of the hoisting tool 5 will not be affected. It is possible to secure a time margin necessary for stopping the tool 5 before it collides with the tip of the boom 1.

[0012]

EFFECTS OF THE INVENTION The roll-up prevention device of the present invention configured as described above has a simple structure, but the distance between the suspension 5 and the tip of the boom 1 at the stop position is smaller than that of the conventional roll-up prevention device. Even if it is set to a small value, it is possible to secure a time margin necessary for stopping the hoisting movement of the lifting device 5 before the lifting device 5 collides with the tip of the boom 1. Therefore, it is possible to achieve the effect that the working range of the mobile crane can be expanded by setting the distance between the lifting tool 5 and the tip of the boom 1 at the stop position to be small.

[Brief description of drawings]

FIG. 1 is an explanatory view of a roll-over prevention device for a mobile crane according to the present invention.

FIG. 2 is an explanatory diagram of a conventional rollover prevention device for a mobile crane.

[Explanation of symbols]

 1 Boom 2 Sheave 3 Hydraulic Drive Winch 4 Wire Rope 5 Lifting Tool 6 Drive Control Device 7 Stop Switch 8 Winding Stop Means 9 Drive Speed Control Means (Throttle Valve) 10 Speed Control Switch

Claims (1)

[Scope of utility model registration request] 1. A wind-up prevention device for use in a mobile crane in which a suspender is hung from the tip of a boom via a wire rope from a hydraulically driven winch pulled out through a sheave at the tip of the boom. Then, in the one provided with a stop switch arranged at the boom tip end and detecting the time when the lifting tool comes to a stop position approaching the boom tip end, and a hoisting stop means that operates according to the detection result of the stop switch, The drive control device of the hydraulic drive winch is provided with a drive speed control means for restricting the drive speed of the winch to a predetermined value or less when the winch is operated, and the distance between the lifting tool and the boom front end disposed at the boom front end is reduced. A speed regulation switch for detecting a position farther than the stop position is attached, and the drive speed regulation means is operated according to the detection result of the speed regulation switch. Winding over-prevention apparatus for a mobile crane, characterized in that the configuration was.