JPH0286597A - Jib derricking speed controller for constructional tower crane - Google Patents

Abstract

PURPOSE:To make stable lifting work performable by setting a jib's derricking angle range to be plural stages so much as it is uprighted, and controlling it so as not to cause force-up speed of the jib by a hydraulic cylinder to be suddenly operated. CONSTITUTION:When a derricking angle of a jib exceeds a range of 47 degrees, it is detected by a derricking angle detector 40, and since a limit switch LS1 is operated by a cam and comes to ON, a relay R1 operates, its contact Lr1 opens but another contact Lr1' closes instead, so that a command signal is selected to a command for throttling a feed oil quantity by an amplifier Am. Therefore a current value to solenoids 32', 32' of a solenoid proportional valve 32 is controlled so as to cause an output signal of the amplifier Am to execute an intermediate restriction, whereby a working supply to a derricking hydraulic cylinder 6 is reduced, thus a jib 3 is uprighted at slow speed. When the jib 3 is uprighted and exceeds a range of 60 degrees, a limit switch LS2 is operated by a cam of the detector 20, and contacts Lr<2>, Lr<2>' of a relay LR2 are opened or closed and thereby the command signal at the amplifier Am is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application: The present invention relates to a device for controlling the jib hoisting speed of a construction tower crane.

Background of the invention: In tower cranes used at construction sites,
When unloading materials, the working radius must be changed frequently, and the jib must be raised and lowered while being unloaded.

Regarding this jib hoisting operation, since the jib was conventionally tilted by a hoisting cable, this operation did not occur suddenly and was relatively stable. However, in recent years, cranes in which the jib is hoisted using a hydraulic cylinder have been adopted as the structure has been simplified, and as a result, the jib's hoisting movement is more rapid than with rope-driven cranes. Since then, there has been a need to control the undulation speed.

Problems to be solved: With conventional rope-driven jib hoisting means, the structure of the rope winding is complicated, and it requires a lot of work to wind the rope at high places when assembling and disassembling the crane. By changing the drive system using a hydraulic cylinder near the base of the shifter, which was necessary and had poor workability, it became possible to streamline the work during assembly and disassembly, but at the same time, it became possible to raise and lower the jib quickly. This was disadvantageous in that it lacked smoothness.

Means for Solving the Problems: The present invention solves these problems and provides a control device that controls the operating speed of the jib to ensure smooth operation when raising and lowering the jib within a set angle range. Our goal is to provide the following.

That is, the present invention provides a construction tower crane that includes:
At or near the jib, via a jib width device in multiple stages,
This control device is connected to an electric control mechanism which is connected to an operating solenoid of an electromagnetic proportional valve provided in a hydraulic fluid line from a hydraulic pressure supply source to a hydraulic cylinder for jib hoisting.

The jib hoisting speed control device of the present invention can be advantageous for the jib configuration by correlating the relationship between this and the hanging load so that the swing speed can also be controlled. In this case, a hanging load detector is installed on the jib or near its attachment, and the detection signal from the hanging load detector is connected via an amplifier to the hydraulic fluid pipe from the hydraulic supply source to the swing motor. The electrical control mechanism is configured such that the operation and turning of the jib are controlled by both the signal transmitted to the operation solenoid of the electromagnetic proportional valve and the detection signal of the jib's heave angle.

Effect: According to the present invention, the jib, '7,
When the jib is hoisted, a hoisting angle detector connected to the base of the jib detects the angle of the jib within a preset angle range and issues a signal accordingly. The angle detection signal is transmitted to the control mechanism for M1 pressure operation, converted into a signal by the command control unit consisting of an amplifier and a controller, and the direct current solenoid of the electromagnetic proportional valve in the hydraulic pipe is output in response to the input current value. , the proportional valve is operated.

Then, the amount of hydraulic oil supplied to the jib hoisting hydraulic cylinder is regulated, and when the hoisting speed exceeds the set range, the jib is controlled to operate at a speed lower or faster than the set speed. Of course, it is also possible to limit the range of undulation angles that operate.

Embodiment: Next, one embodiment of the present invention will be explained with reference to the drawings.
It is as follows.

Figure 1 shows a construction tower crane that uses hydraulic cylinders to raise and lower the jib.
The swing motor (5) and the hydraulic cylinder (6) for luffing the jib (3) are driven by the hydraulic unit (4) mounted on the turning table (2) installed at the top of the jib (1). ing. (4) is the outer mass l-1 (7) is the jib support frame, (8) is the hoist, (9) is the suspension rope, θυ is the suspension pulley block, and OD is the guide pulley.

The hydraulic cylinder (6) for jib hoisting has its base end connected to a turning plate (2).
) is supported with a pin via a bracket, and the end of the piston rod is connected to the base of the jib (3) with a pin so that it stands upright.

The luffing angle detector (a) of the jib (3) has multiple cams aligned on one axis in a box-shaped body with a receiver mounted on the side of the jib support frame (7) via a stand (7). Arrange and
Each limit switch is operated by this cam, and the lever is attached to one end of the cam mounting shaft. υ and the pitch α provided near the pivot axis a3 of the jib (3).
The hair is connected with a connecting rod (A) so that the undulation angle of the jib (3) is directly transmitted to the cam shaft to rotate the cam, and the cam group turns on and off the limit switch in the required angle range. It seems to be turned off; it is stiff.

As an example of the hydraulic control mechanism, as shown in Fig. 2,
An electromagnetic proportional valve (a) is interposed in the oil supply path from the hydraulic pump 31) of the hydraulic unit to the jib hoisting hydraulic cylinder (6) on the turning table (2), and the electromagnetic proportional valve (c) operates the hydraulic cylinder. The operation of (6) is controlled. Note that in the hydraulic control M] TFI structure (1), equipment not directly related to the present invention is omitted. In the figure, the symbol (to) is the IJ IJ-F valve, (b) is the reverse IF valve, (
) is a coupler.

The electromagnetic proportional valve (to) in the hydraulic control mechanism ■ and the jib's heave angle detector ■ are signals detected by the heave angle detector 1j by an electric control mechanism as illustrated in FIG.
This is so that the electromagnetic proportional valve (2) is controlled and operated.

The undulation angle detector in this electric control circuit has angle detection contacts provided in two stages (however, it is possible to arbitrarily provide more contacts than this). The contact (LSI) is set to turn on at an angle of 47°. The contact (LS2) is set to turn on at an angle of 60' or more. All of these can be set to operate at any angle, and are not limited to these values. The contact point (LS) detects the lowest angle of the jib and does not operate below approximately 6 degrees.

A relay (LRI) connected to each of these contacts, (LR2
) to transmit a signal to the amplifier (Am), and the electric signal output from this amplifier (Am) changes the current value for the DC solenoid of the electromagnetic proportional valve 02, and moves the movable iron core. By controlling the
It is possible to proportionally control the amount of hydraulic oil supplied from the hydraulic pump (3) to the luffing hydraulic cylinder (6), and change the advancing and retreating speed of the piston rod of the hydraulic cylinder (6), that is, the hoisting speed of the jib (3). It is possible to do so. The symbol in the figure (R
3I) (R52) is a relay for restricting either one of the jib hoisting operations (R5l) (R52α is (R5I)
) (RS2) B contact. (Lrl) (Lr2) is the B contact of the relay (LRI) (LR2). (Lr 1)
(Lr2) is the A contact of the relay (LRIXLR2). (
MS ) is the magnetic switch operation relay (McA ) of the hydraulic pump drive circuit, and its contact. (PBl) (P
B2XPB3) (PH1) is a push button switch. Crystal is a direct current solenoid of electromagnetic proportional valve.

In addition, if the undulation angle in the undulation angle detector (A) is divided into more than the above example, the number of detection cams and limit switches (LSn) will be increased as required, and a corresponding command signal will be given to the amplifier (stone). The relay (LRn) may be arranged, and its contacts (not shown) may be provided on the signal input side of the amplifier (Am) in the manner described above.

For cranes that have a control device configured in this way,
When raising and lowering the jib (3) during work, in this specific example, the jib is set at its lowest position at 6 degrees from the horizontal position (below this, the push button switch (PH1) is pressed).
), by operating the jib (3) in the direction of raising it, the 47'
Since the up-and-down angle detector j does not emit the following signal in the range up to (but not limited to), the hydraulic oil supply condition from the hydraulic pump 61) to the hydraulic cylinder (6) is in a steady state. Therefore, the luffing hydraulic cylinder (6) operates normally (the electromagnetic proportional valve (6) keeps the hydraulic oil flowing in the maximum flow layer).

If the jib's rising angle exceeds 47°, this is detected by the luffing angle detector (a) and the limit switch (LS
I) is operated by the cam and turned on, so the relay (LRl) is activated, its contact (Lr1) opens, and the contact (Lr1) closes, so the command signal from the amplifier (Am) reduces the amount of oil supplied. Therefore, the output signal of the amplifier (Am) is switched to the command, so that the current value to the solenoid crystal of the electromagnetic proportional valve (a) is controlled so as to perform intermediate throttling, and the hydraulic oil to the hydraulic cylinder for luffing (6) is controlled. The supply amount decreases and the jib (3) stands up at low speed. When the jib (3) rises further and exceeds 60 degrees, the limit switch (LS2) is operated by the cam of the detector (a) and the relay (
LR2) is activated, its contact (Lr2) opens, and its contact (Lr2) closes, so the command signal at the amplifier (Am) is switched, and the output signal is output from the electromagnetic proportional valve (to) so that it rises at the slowest speed. The current value to the solenoid zone (a) is controlled, the opening degree of the valve is further narrowed, and as a result, the jib raising speed becomes gentler. Of course, a limit switch (not shown) is provided at the maximum standing position, and the robot stops at the limit position.

To operate the erected jib (3) in the lowering direction, turn on the push button switch (PH1) to operate in the opposite manner to the above. The operating speed of the hydraulic cylinder (6) will be gradually increased.

In controlling the hoisting speed of the jib in this manner, if the set angle range is subdivided, the speed can be changed in multiple stages.

In addition, the operating speed of the jib is controlled at a specific angle as described above, and in addition to this, the hanging load can be increased as the lifting angle increases due to changes in the working radius. If set to , the working conditions for the crane will be leveled out, and the force acting on the jib, mast, etc. will not fluctuate greatly and will be stable.

An example of an electrical control system employing such a method is shown in FIG. The same parts as those shown in the above specific example are given the same reference numerals. Code (LS3) (LS4
) (LS5) is the contact point of the hanging load detector (g), and the hanging rope (9
) by means of an actuating rod connected to the end of the
0 to 911200&9. 1500 #9 is incorporated in a structure that opens when each hanging load is detected in the order. (LR3XLR4) (LRs) are relays operated by the detector. (LRO) is overload limit auxiliary relay, (Lr3) (Lr4) (Lr5
) are A contacts of relays (LR3) (LR4) (LR5).

(LrO) is the A contact of the auxiliary relay (LRo).

(R53XR54) is a hoisting/lowering auxiliary relay, (
R53) (R5 is their B contact.

If such a control mechanism is provided, the lifting angle of the jib (3) can be regulated by the limit switch (LS2), so that the hanging load can be reduced to 15° within the range of, for example, 60°.
If it becomes 00kq or more -H, the hanging load is over (the contact (LS5) of the hanging load detector 00 is open, so the excitation of the relay (LR5) stops, and the contact (Lr5) of the overload limit circuit is opened, the contact (LrO) of the relay (LRO) is opened, and both the jib lowering circuit and the sling hoisting circuit are cut off), and the lifting operation is stopped.

Effects of the invention: According to the present invention, when the jib is hoisted during lifting work of materials etc. by a crane, the hoisting angle range is set in multiple stages as the jib rises, and the lifting speed of the jib by the hydraulic cylinder is adjusted. By controlling the load so that it does not operate suddenly, no excessive load is applied to the jib, and no unnecessary inertia is exerted on the hoisted load, allowing stable landing work. Of course, the strength of the jib does not need to be increased excessively, so the weight can be reduced accordingly, reducing the burden on the driving parts, etc., and the synergistic economic effects of these factors can be enhanced.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a construction tower crane incorporating the device of the present invention, Fig. 2 is a diagram showing a control system of a hydraulic cylinder for luffing, Fig. 3 is a circuit diagram showing an electric control mechanism, and Fig. 4 is a diagram showing an example of a construction tower crane incorporating the device of the present invention. The figure is a circuit diagram of an electric control mechanism that associates the hanging load with the undulation angle. (2)... Turning machine (3)... Jib (5)
... Swing motor (6) ... Hydraulic cylinder for jib hoisting (7) ... Jib support frame (1)
...Luff angle detector (9)...Sling rope
(To)...Hydraulic control mechanism OD...Hydraulic pump
(2)...Electromagnetic proportional valve cry...Lifting load detector (LSI) (LS2) (LSO)...Contacts of the undulation angle detector (LS3) (LS4) (LS5)...Lifting load detection Contacts (LRI) (LR2) (LR3) (L
R4) (LR5)...Relay (R5t) (Rs2) (
gs3) (R54) ... Auxiliary relay (L, rt)
(Lrz) ... Relay B contact (Lrl) (Lr
2) (Lr3) (Lr4') (Lr5') (LrO)・
...Relay A contact (Am)...Amplifier Figure 1 Figure 2 Figure J

Claims (1)

[Claims] 1. In a construction tower crane, a jib hoisting angle detector is installed near the jib or its attachment point, and the jib hoisting angle detector detects the detection signal of each set angle detection section through an amplifier. A construction tower crane, characterized in that the construction tower crane is connected to an electric control mechanism configured to transmit information to an operating solenoid of an electromagnetic proportional valve provided in a hydraulic oil pipe from a hydraulic pressure supply source to a hydraulic cylinder for jib hoisting. jib hoisting speed control device.