JPS60191992A - Lifting gear for crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a double hoist for an inverter-controlled electric hoisting winch crane.

(Prior Art) Fig. 1 shows an example of a crane having a hoisting jib. and control panel 1
A jib 5 is mounted on the front part of the revolving body 1 so that it can be raised and lowered freely, and the hoisting rope 7 that is wound up and let out by the hoisting winch 3 is attached to a guide sheave 17 at the top of the A frame 4. The sheave block 19 at the top of the A frame and the bridle 18 connected to the top of the jib 5 via the penguin rope 8 are hung in multiple numbers, and the jib 5 is hoisted by the operation of the hoisting winch 3. It has become. In addition, the two ropes 6 wound up and unwound by the hoisting winch 2 are separated from the shift point sheave 2o at the top of the jib 5, the sheave 21 at the lift 9, and the section 81) at the jib 5. Shift point sheave 22 is hung and turned, and the end is attached to the jib 5. Load detector (roto cell) + n Lj h4btl 1. f1. 'l
X iba 壬h'h中Bu I convex+aya L It converts the tension of the rope 6 into an electrical signal, and the output signal is sent to the jib angle detector 1 which converts the angle of the shib 5 into an electrical signal.
1 output signal is manually inputted to the electronic moment trimmer 12 provided in the control panel 16. The moment limiter 12 is a device to prevent overload, and stores the rated load according to the working radius for each jib length in advance.
It has the function of calculating the actual load and working radius based on the signal from 1, comparing it with the stored value, and outputting a signal if it exceeds the value.

In such a lane, the hoisting device handles various loads within the rated load range, but if an electric motor whose speed is controlled by an inverter is used as the drive device for the hoisting winch 2, the maximum load can be hoisted at the maximum speed. Since the maximum output is when the motor is running - the capacity of the motor has conventionally been determined by this maximum output. However, hoisting an empty hook is the operation that requires the highest speed, and when the load is large, it is rarely necessary to operate at maximum speed for safety reasons. In other words, conventionally, the rated output of an electric motor is determined based on the maximum speed of the maximum load with little possibility of operation, so in most cases, the motor is operated at an output that is considerably lower than the rated output. This is uneconomical. However, for this reason, winding a motor with a small rated output
If used as a winch drive device, safe driving will be impossible.

(Object of the Invention) In view of the points mentioned above, the present invention makes it possible to use a small-capacity electric motor for driving a hoisting winch, and also provides a crane hoisting winch having a configuration that ensures safe operation. The purpose is to provide a device a.

(Structure of the Invention) In order to achieve this object, the present invention provides a jib crane that uses an electric motor whose speed is controlled by an inverter device as a winch drive device, and is equipped with an electronic moment limiter. As a moment limiter, the inverter device has a function of outputting a signal every time the actual lifting load exceeds a preset load of 1 or more regardless of the working radius. The present invention is characterized in that overload is prevented by providing a circuit that selects a lower speed as the speed of the motor No. 111 based on the force generated by the limiter.

(Example) The xr details of the present invention will be explained below using examples. In the present invention, the load detector 10, the shift angle detector 11, and the electronic moment limiter 12 shown in FIG.
In addition to the functions described in 110, the Momen I limiter 12 has a function that outputs a signal every time the load exceeds one or more preset load values, regardless of the working radius. I'll leave it there.

FIG. 2 shows the electric motor 15 for driving the hoisting winch 2 (--
JIQ uses a squirrel cage motor as this electric motor).
The lifting load W detected by the reference 10 is the set load Wo (see Figure 3), which is stored in the moment limiter 12.
This is the a contact of a relay (not shown) that is excited by a signal generated in the range (W > W o ) exceeding W > W or the maximum load W + (see Figure 3). This is the b contact of a relay (not shown) that is excited by a signal generated by 'W+). 2M is the contact 2
The relay 3 is energized when it closes, and 2+nb is its b contact.

Reference numeral 14 designates an operating switch FBI for instructing the electric motor 15 to rotate in the winding direction and unwinding direction of the rope 6 (that is, in the winding direction and lowering direction of the suspended load, respectively).

PH1 and operation switch PB for commanding high speed rotation
It consists of 3. HU, HD, HH,'HL are
These are relays for hoisting, lowering, and high-speed and low-speed operations of suspended loads, and the electric motor 15
This is used to create operation control signals. The contact points of these relays are indicated by the lowercase letters of the alphabet followed by a or b.

- the impark device 13 of the electric motor 15 has an input terminal R
, S, and T are rectified once, and a variable frequency AC output is output to the output terminal U.

V and W are outputs to the electric motor 15, E is a ground terminal, and a, b, and c are control power terminals.

d and e are input terminals for rotation direction command, f is frequency dispersion')i
! The signal is the input terminal, g and h are the input terminal f for power supply number 4a.
− is. PMI and PM2 are a high-speed potentiometer and a low-speed potentiometer, respectively, and are capable of setting the speed of the caulking motor 15.

In this circuit, if the lifting load W detected by the load detector 10 is less than the set load Wo set in the moment limiter 12, the relay contact 23 is open, so the relay 2M is inactive and its b contact 2mb remains closed. Therefore, when the lifting load W is small, operating the high-speed command operation switch FB3 causes the coil of the relay HH to connect to the contact 2.
Since the current is applied through mb, its a contact hha is closed, and the tl pressure signal of the high-speed potentiometer PM1 is applied to the frequency setting signal input terminal f, which corresponds to the voltage set by the high-speed potentiometer PMI. Since a high frequency is selected and relay HH (7) b contact hhb connected to the coil of relay HL opens, relay H'
The action of L is prohibited. In this case, the operating switch for hoisting command FBI or the operating switch for lowering command PB2
When the relay HU or HD is operated, the A contact hua or hda is closed, a signal is applied to the rotation direction command input terminal d or e to command the rotation direction, and the power supply HU or HD is energized. An actuation signal is applied to the i'J signal input terminals g and h, and the electric motor 15 rotates at a high speed Vo (see FIG. 3) in the winding or unwinding direction of the hoisting rope 6.

On the other hand, as above, when the lifting load W is
2, if the high-speed command operation switch PB3 is not operated, the relay HH will not be energized and its b73 point hhb will remain closed, so the relay HL will not be energized. Since the coil yM+ remains energized and the a contact hla remains closed, a low output frequency corresponding to the voltage set in the low-speed potentiometer PM2 is set. Therefore, in this situation yd, operation f[switch FBI or P
When H1 is operated, the electric motor 15 rotates at a low speed V+ (see FIG. 3). That is, in the range where the suspended load W is less than the set load Wo, it is possible to select whether to raise and lower the suspended load at high speed or at low speed.

On the other hand, when the lifting load Wl)'-4ij exceeds the set load Wo, the relay contact 23 closes, so the relay 2M is energized, its contact 2mb opens, and the high-speed command operation switch P133 is operated. Since relay HH is not energized and its B contact hhb remains closed, the coil of relay HL remains energized and its A contact hla remains closed. An output frequency corresponding to the voltage set in potentiometer PM2 is set. That is, in a range where the lifting load W exceeds the set load Wo, the hanging load can only be lowered by y1 at a low speed.

Further, when the lifting load W exceeds the maximum load W1, the relay contact 24 is opened by the moment limiter 12,
Since relays HU and HD are not excited, electric motor 15 does not operate.

-1 series, high-speed operation is possible when the lifting-L load W is less than the set load Wo, and low-speed M +/i is possible when it exceeds the set load Wo. As shown, the relationship between the set load Wo, the maximum load W1, and the low speed v1 and high speed Vo is as follows: The output of the electric motor 15 is constant along a constant output curve A, that is, WIxV1=Woxv.

If the settings are made so as to maintain the relationship, the capacity of the conventional electric motor 15 (output B ), the capacity of the electric motor 15 can be minimized, which is economical. Furthermore, in the case of a large load, the vehicle can only be operated at low speeds, making it safer.

In the above embodiment, explanation was given by taking 2-speed operation as an example, but it is also possible to further increase the speed setting means such as a potentiometer to provide 3-speed or higher speed operation, which is even more economical. and safe.

(Effects of the Invention) As described above, in the present invention, as an electronic moment trimmer, a signal is output every time the hoisting cart exceeds a preset value of 1 or more regardless of the working radius. In addition, the inverter device is configured to prevent overload by providing a circuit for selecting a lower speed as the speed of the electric motor based on the signal issued by the electronic moment trimming. Therefore, even with a small capacity electric motor, a wide speed range can be selected as the lifting/lowering speed of the suspended load, and a large load can be lifted with a small capacity electric motor. Therefore, according to the present invention, it is possible to reduce the capacity of the drive motor of the hoisting device. Further, as the load increases, the speed automatically becomes lower, so safe operation is ensured.

[Brief explanation of drawings]

Fig. 1 is an overall diagram of a general jib crane, Fig. 2 is a control circuit diagram of a hoisting motor showing an embodiment of the present invention, and Fig. 3 is a lifting load and hoisting when using the present invention. It is a figure showing an example of the relationship with speed. 2... Hoisting winch, 12... Electronic moment limiter, 13... In-heater device, 14... Operation switch, 15... Electric motor, HU, HD, HH, HL
, 2M...Relay, PMI...High-speed potentiometer, PM2...Low-speed potentiometer Patent applicant Hitachi Construction Machinery Co., Ltd. Agent Patent attorney Masami Akiki Agent Patent attorney Masaru Wakata- +j-1-Kijjaku Procedural Amendment (Voluntary) May 211, 1980'' Kazuo Wakasugi, Commissioner of the Japan Patent Office1, Indication of this case, Patent Order No. 47095 of 1982, 2, Name of Invention: Crane Volume - Device 3 Amendment Case Relationship Patent applicant address: 2-6-2 Otemachi, Chiyoda-ku, Tokyo Name:
(552) Hitachi Construction Machinery Co., Ltd. Representative Bunpei Nishimoto 4, Agent 105 Address 1-6-14 Nishi-Shinbashi, Minato-ku, Tokyo Address 1-8-612, Ichiyo Minami 1rl, Chiba Prefecture 7. Contents of the supplement As per the attached sheet (1) In the specification, l'a, b, cj in line 8 on page 7 are changed to 1'f
, gj. (2) l"l\1 in the middle, page 7, line 9 ['fj in 1lb
Revise it as j. (3) In the same book, page 7, line io to page 11, line [1g. h is ~. j, ii'a is a starting signal self-holding relay terminal, C is a common terminal for the control circuit, and h is a starting signal 5) input terminal. Correct it with J. (4) In the same book, “Frequency setting signal input terminal” on page 8, line 4 to line 5 of the same page is corrected to “Control power supply terminal blade.” (5) In the same book, on page 8, line 15, “Power on/off signal Input end/-
Correct g, h, and I as W start signal input terminal and start signal self-holding relay terminal aj. I"2

Claims (1)

[Claims] In a jib crane that is equipped with an electric motor whose speed is controlled by an inverter device and is equipped with an electronic moment limiter, the actual lifting load is set in advance regardless of the working radius. The inverter device is provided with a function of outputting a signal every time one or more set loads are exceeded, and the inverter device is configured to select a lower speed as the speed of the electric motor based on the signal issued by the electronic moment limiter. A crane hoisting device characterized by being equipped with a circuit that prevents overload.