JPH03232692A - Derricking angle detector - Google Patents

Abstract

PURPOSE:To detect an accurate derricking angle in a jib with one detecting means by detecting the elongation value of a rod of a cylinder turning the jib with an elongation value detecting means, and operating the jib's derricking angle from the elongation value with an operational means. CONSTITUTION:A cord reel 30, detecting travel of a piston rod 25, is installed in a jib 20, and a cord 31 is pulled out of the cord reel 30 as long as conformed to elongation value of the piston rod 25. A potentiometer 32 is attached to the cord reel 30, and the elongation value of the rod 25 is detected by the cord reel 30 and the potentiometer 32. When the cord 31 is drawn out, a shaft 34 rotates together with a take-up roll 33 according to the drawn value, and this rotation turns a turning shaft 37 of the potentiometer 32 via gears 35, 36, thus rotational frequency of the turning shaft 36 is outputted as an electric signal. A control unit consisting of a microcomputer or the like operates a derricking angle in the jib 20 from voltage of this electric signal.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for detecting a luffing angle with respect to the boom of a jib rotatably attached to the tip of a boom provided on a swivel base of a crane. This invention relates to a detection device.

(Prior Art) Generally, a mobile crane is provided with a telescoping boom on a swivel base, and a jib is rotatably and removably provided at the tip of the telescoping boom. This allows the object to be reliably placed in the desired position by extending and contracting the boom depending on the size of the surrounding space and the lifting position, and by rotating the jib and adjusting the angle of the jib relative to the telescopic boom. Moreover, this is to ensure safe lifting.

By the way, the overload of the crane varies depending on the heave angle of the jib, and the jib performance of AML (crane overload prevention device) is set depending on the heave angle. Therefore, it is necessary to accurately detect the undulation angle.

Therefore, in order to detect the heave angle, an angle detector 3.4 is attached to the telescopic boom 1 and the jib 2, as shown in Fig. 7, and the angle detector 3 measures the inclination σ of the telescopic boom 1 with respect to the vertical line. The angle detector 4 detects the inclination γ of the jib 2 with respect to the vertical line, and from these, the heave angle θ of the jib is determined from the following equation.

θ=end−σ ・・・・・・■ (Problem to be solved by the invention) However, when the telescopic boom 1 is extended or an object is lifted, as shown in FIG.
is deflected, and the inclination of the jib 2 with respect to the vertical line becomes γ-, making it impossible to determine θ from the above equation 0.

To accurately determine O, it is sufficient to install a detector at the pivot point 5 between the telescopic boom 1 and the jib 2 and detect the amount of rotation of the jib 2 relative to the telescopic boom 1. Since it is attached freely, there is a problem in that it is difficult to install it.

Therefore, as shown in FIG. 9, an angle detector 3 is provided at the tip of the telescopic boom 1 to accurately detect θ. However, since two angle detectors 3.4 are required, there is a problem in that it becomes expensive.

(Object of the Invention) Therefore, the present invention was made in view of the above-mentioned problems, and its purpose is to detect a heave angle that can accurately detect the heave angle of a jib using a single detection means. The goal is to provide equipment.

(Means for Solving the Problems) In order to achieve the above object, the present invention detects the luffing angle with respect to the boom of a jib rotatably attached to the tip of a boom provided on a swivel base of a crane. A heave angle detection device comprising: an elongation amount detection means for detecting an elongation amount of a rod of a cylinder for elevating the jib; and an arithmetic means for calculating a heave angle of the jib from the elongation amount. Features:

(Function) Since the present invention has the above configuration, the extension amount detection means detects the extension amount of the rod of the cylinder that rotates the jib, and the calculation means calculates the heave angle of the jib from the extension amount.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a side view showing a crane truck to which the undulation angle detection device of the present invention is applied. In FIG. , 12 is a telescopic boom installed on the swivel base 11, which can be set at any angle with respect to the vertical line by means of a hydraulic cylinder 13. A boom head 14 is formed at the tip of the telescopic boom 12, and a jib 20 is attached to the boom head 14 in a detachable manner and rotatable in a vertical plane.

As shown in FIG. 2.3, the jib 20 has a jib head 21 provided at the tip and fork-shaped legs 22 and 23 provided at the rear end. A sheave K is attached to the Y for hoisting the object. The legs 22, 23 are rotatably attached to a support shaft 15 provided on the lower side of the boom head 14. The jib 20 includes a hydraulic cylinder 24 for rotating (raising and lowering) the jib 20, and a piston rod 25 that covers the piston rod 25 of the hydraulic cylinder 24.
A guide case 26 extending in the direction in which the guide case 26 extends is installed.

A slide case G is attached to the tip of the piston rod 25, as shown in FIG. 4.5, and slides within a guide case 26 as the piston rod 25 moves back and forth. Moreover, at the tip of the piston rod 25,
A guide shaft 27 extending in the horizontal direction is provided passing through the slide case G, and both ends 27 of this guide shaft 27
a, 27 b are side plates 26a, 26 of the guide case 26.
It protrudes from the guide hole 28 formed in b. The tip of a tension rod 29 is pivotally attached to both ends 27a and 27b (see FIG. 3).
A rear end portion of the boom head 14 is pivotally connected to a bin P provided on the upper side of the boom head 14.

Then, when the piston rod 25 retreats, the jib 20 moves to the Q
When the piston rod 25 moves forward, the jib 2
0 rotates in the R direction (see Figures 1 and 2). In this embodiment, the undulation angle of the jib is set to 0 degrees to 45 degrees.

Further, the jib 20 is provided with a cord reel 30 behind the cylinder 24 for detecting the amount of movement of the piston rod 25, as shown in FIG. 4.5. A cord 31 extends from the cord reel 30, and the tip of the cord 31 is fixed to the slide plate G, so that the cord 31 is pulled out from the cord reel 30 by a length corresponding to the amount of extension of the piston rod 25. It has become. A potentiometer 32 is attached to the cord reel 30 to detect the amount by which the cord 31 is pulled out. Then, the rod 25 is connected to the cord reel 30 and the potentiometer 32.
An elongation amount detection means for detecting an elongation amount is configured. Note that T represents the cord reel 30 and the potentiometer 32.
This is a case that covers.

As shown in FIG. 6, the potentiometer 32 is connected to a gear 35 attached to a shaft 34 of a take-up roll 330 for winding the cord 31, and a gear 36 meshed with the gear 35. When the cord 31 is pulled out, the winding roll 33 and shaft 3
4 rotates, and this rotation rotates a rotating shaft 37 of a potentiometer 32 via gears 35 and 36, and the potentiometer 32 outputs the amount of rotation of this rotating shaft 36 as an electrical signal.

In this case, for example, a slider (not shown) is moved on a ring-shaped sliding resistance (not shown) by rotation of the rotating shaft 36, and a voltage corresponding to the amount of movement is outputted as an electric signal.

A control device (not shown) comprising a microcomputer (not shown) or the like based on the voltage of the electric signal is then used.
is used to calculate the heave angle of the jib 20. This calculation is performed by, for example, determining in advance the relationship between the amount of withdrawal of the cord 31, that is, the amount of extension of the piston rod 25, and the undulation angle of the jib 20, and storing a map representing this relationship in a memory.

Now, for example, as shown in FIG. 2, the piston rod 25
is not moving forward, that is, when the jib 20 is at the two-dot chain line position, the cord 31 is not pulled out from the cord reel 30 and the potentiometer 32
An electrical signal of a voltage indicating that the amount of cord 31 to be drawn out is zero is output from. Then, the control device calculates the heave angle of the jib 20 from this electrical signal. In this case, the undulation angle of the jib 20 is 45 degrees.

Then, as the piston rod 25 is moved forward, the jib 2
0 rotates in the direction of arrow R, - direction, code reel 3
0, the cord 31 is pulled out by a length corresponding to the amount of extension of the piston rod 25, and the rotating shaft 36 of the potentiometer 32 rotates in accordance with the amount of extension of the piston rod 25. An electrical signal of the same voltage is output. Then, from this electrical signal, the control device calculates the heave angle of the jib 20 based on the map stored in the memory.

In this way, since the undulation angle of the jib 20 can be determined with one extension amount detection means, the structure of the device is simple and the device is inexpensive. Furthermore, since the calculation of the undulation angle is performed based on the map stored in the memory, an accurate undulation angle can be determined.

In the above embodiment, the amount of extension of the piston rod 25 is determined using the cord reel 30, but the invention is not limited to this.
An encoder that generates a pulse every time the piston rod 5 moves a predetermined distance may be attached, and the amount of extension of the piston rod 25 may be determined by counting the pulses output from the encoder. Alternatively, the amount of extension of the piston rod 25 may be determined by disposing a sliding resistance along the piston rod 25 so that the slider moves on this sliding resistance as the piston rod 25 advances and retreats. good.

(Effects of the Invention) According to the present invention, there is provided an extension amount detection means for detecting the extension amount of a rod of a cylinder for raising and lowering a jib, and a calculation means for calculating a heave angle of the jib from the extension amount. Therefore, the undulation angle of the jib can be accurately determined with one detection means, and the structure of the device is simple and inexpensive.

[Brief explanation of drawings]

Fig. 1 is a side view of a crane truck to which the detection device of the present invention is applied, Fig. 2 is a side view of the jib, Fig. 3 is a plan view showing the hydraulic cylinder installed on the jib, and Fig. 4 is a side view of the jib. Figure 5 is a side view showing the installed cord reel and hydraulic cylinder; Figure 5 is a plan view showing the cord reel and hydraulic cylinder installed on the jib; Figure 6 is a diagram showing the connection between the cord reel and the potentiometer. Figure 7 is an explanatory diagram showing the conventional principle of determining the heave angle of the jib relative to the boom. Figure 8 is an explanatory diagram showing that it is no longer possible to determine the accurate heave angle when the boom is deflected. , FIG. 9 is an explanatory diagram showing the installation position of a conventional angle detector. 11... Swivel base 12... Telescopic boom 24... Hydraulic cylinder 25... Cylinder rod 30... Cord reel 32... Potentiometer

Claims (1)

[Scope of Claims] A luffing angle detection device for detecting a luffing angle with respect to the boom of a jib rotatably attached to the tip of a boom provided on a swivel base of a crane, comprising: a cylinder for hoisting the jib; A luffing angle detection device comprising: an elongation amount detection means for detecting an elongation amount of a rod; and an arithmetic means for calculating a luffing angle of a jib from the elongation amount.