JPH0637265U - Electric crane - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to open and close the circuit of the electric motor for powering the crane and control the speed by operating only one lever, and to reduce the size of the operation panel to which the operation lever is attached. Provide a crane. A potentiometer 33 is used as a means for generating an inverter control signal by using an electric power motor for inverter control in part or all of a power unit. A universal lever 16 is provided as an operating means of the electric motor for controlling the inverter. An electric motor circuit opening / closing switch is provided coaxially with a rotary shaft rotated by the operation of the universal lever 16 so that the contact opens at the neutral position of the lever and closes at a certain tilt angle or more. Further, the slider of the potentiometer 33 is provided on either one of the rotary shaft and the case of the potentiometer covering the rotary shaft, and the annular resistor of the potentiometer 33 is provided on the other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electric crane, and more particularly to an operation panel for starting, stopping and speed control of an inverter-controlled electric motor when using an inverter-controlled electric motor for all or part of a power electric motor.

[0002]

[Problems to be solved by conventional techniques and devices]

 FIG. 5 shows a jib crane as an example of an electric crane. A swivel frame 3 is installed on a base frame 1 through a swivel bearing 2, and a swivel machine 6 installed on the swivel frame 3 operates the swivel frame 3. The turning frame 3 turns. A hoisting winch 7 for hoisting and hoisting a hoisting rope 13 for hoisting a suspended load through a hook 14 and a hoisting rope 10 of a jib 5 (the hoisting rope 10 is a hoisting frame). 3 is wound around between the sheave block 11a on the top of the A frame 4 installed on the 3 and the bridle 11b connected to the top of the jib 5 via the pendant rope 12.). An undulating winch 8 and a control panel 9 for controlling the electric motors for powering the turning machine 6 and the winches 7 and 8 are installed.

Conventionally, in such a crane, as shown in FIG. 6, for example, as a rotation motor 6A of a swivel machine 6, pole number conversion (in the illustrated example, circuits 4p and 8p for switching to 4 poles and 8 poles) is used. The method of changing the turning speed to the second speed has been used. That is, the operation panel 20 has a high speed contact 20A, a low speed right turning contact 20B and a low speed left turning contact 20C, and the control circuit has a high speed electromagnetic contactor SH and a high speed contact. It has a right turn electromagnetic contactor SR, a high speed left turn electromagnetic contactor SL, a low speed right turn electromagnetic contactor SRX, and a low speed left turn electromagnetic contactor SLX. SHi, SRi, SLi, SRXj, SLXj (where i = 1, 2, 3, j = 1, 2) are contacts of the electromagnetic contactors SH to SLX.

FIG. 7 shows an operating board that has been used in a crane having such a pole-changing electric motor. Reference numeral 15 is a universal lever for operating a hoisting winch 7, and 16 is a swivel machine 6 and a hoisting winch 8. A universal lever for operation, 17 is a lamp for indicating power on / off, 18 is a power on switch, and 19 is a power off switch.

FIG. 8 shows the universal lever 16. The universal lever 16 has a cam switch 22 whose contacts are opened and closed by moving the universal lever 16 in the AA 'direction and a universal switch 16 in the BB' direction. It has a cam switch 21 for opening and closing the contacts. Although the internal structure of these cam switches 21 and 22 is not shown, a rotary shaft is built in these switches 21 and 22, and a rotary shaft side movable contact and a cam associated with the rotation of the rotary shaft are provided. The switch is turned on and off by contacting and opening the fixed contact fixed to the casing side of the switch by the rotation of the rotary shaft. The contact 20A shown in FIG. ~ 20C is configured. That is, as shown in FIG. 9, when the universal lever 16 is in the neutral position in the AA 'direction, the swing motor 6A is in the stopped state, and the turning motor 6A is in either AA' (right-left) direction. When the lever 16 is moved to a certain angle, the contact 20B or 20C shown in FIG. 6 is closed at a certain tilt angle or more, and a low speed right turn or a low speed left turn is performed, and the lever 16 is moved to the maximum tilt angle in the A or A'direction ( When tilted to, for example, 30 degrees, the contact point 20A is closed, and high-speed right turn or left turn is possible.

However, when such a pole number conversion type electric motor is used as the swing motor 6A, there is a drawback in that it is impossible to finely adjust the speed.

As a method capable of solving such a drawback, there is a method of controlling the speed of a swing motor 6B composed of a cage motor by an inverter 31 as shown in FIG. The inverter 31 of FIG. 10 has R, S, and T input power supply terminals, output terminals U, V, and W connected to the swing motor 6B, a ground terminal E, a start signal self-holding relay terminal a, and a frequency setting signal. It has an input terminal b, a control circuit common terminal c, forward and reverse signal input terminals d and e, control power supply terminals f and g, and a start signal input terminal h. S R1 to SR4 and SL1 to SL4 are contacts of electromagnetic contactors SR and SL that are excited by turning on the push button switch 24 or 25, and 23 is a potentiometer for speed control.

FIG. 11 shows a conventional operation panel 30 used in the control circuit shown in FIG. 10, 23 is the potentiometer shown in FIG. 10, 18 and 19 are the power on / off switches described above, and 24 is the power switch. , 25 are push button switches for opening and closing the motor circuit shown in FIG. 10, 26 and 27 are hoisting and lowering switches, and 28 and 29 are switches for raising and lowering the jib 5, respectively.

This device sets a desired speed in advance by adjusting the potentiometer 23, and then operates the push button switches 24 and 25 to operate the motor 6B to turn right or left. Let If such an inverter-controlled type is used, the driver can continuously select the desired speed by adjusting the potentiometer 23, that is, continuously variable transmission is possible, and the swing motor 6B and There is an advantage that the cage motor used later is inexpensive and robust. However, when performing continuous continuously variable speed operation or changing the turning speed during operation, the potentiometer 23 must be adjusted with one hand while the push button switches 24 and 25 must be operated with the other hand at the same time. And it is very inconvenient.

On the other hand, in Japanese Utility Model Publication No. 54-20781, a gear having a large diameter is attached to a rotating shaft rotated by an operating lever, a gear having a small diameter is meshed with the gear, and a potentiometer is attached to a shaft of the gear having a small diameter. It has been proposed to mount the electric motor and use the output signal of the potentiometer as a control signal for the electric motor of the crane to operate the electric motor at a speed corresponding to the angle of the operating lever. In addition, Japanese Utility Model Laid-Open No. 60-165386 also discloses a structure in which two large and small gears are used to output the rotation of a rotary shaft as an electric signal from a potentiometer.

However, if the configuration in which the potentiometer is actuated by the rotation of the rotating shaft by meshing with the two large and small gears in this way, a space for accommodating these gears becomes necessary, and the operation panel becomes large, There is a problem in that it is disadvantageous in terms of installation and operability in a small cab. In particular, when a universal lever is used as the operation lever, there is a problem that the device around the potentiometer becomes large.

In view of the above problems, the present invention makes it possible to open and close the circuit of the electric motor for powering the crane and control the speed by operating a single lever, and an operation panel to which an operation lever can be attached. It is an object of the present invention to provide an electric crane that can be downsized.

[0013]

[Means for Solving the Problems]

 The present invention relates to an electric crane that uses an electric motor for power control for controlling an inverter in a part or all of power units and has a potentiometer as a means for generating an inverter control signal. An electric motor circuit opening / closing circuit that has a universal lever as a motor operating means and that opens a contact at the neutral position of the lever on the same axis as the rotating shaft rotated by the operation of the universal lever and closes the contact at a certain tilt angle or more. A switch for use is provided, and at the same time, a potentiometer slider is provided on one of the rotary shaft and a potentiometer case covering the rotary shaft, and a potentiometer annular resistor is provided on the other. .

[0014]

[Action]

 In the present invention, when the universal lever as the operation lever is operated from the neutral position to the front and rear and to the left and right, the switch of the electric motor is turned on when the lever is slightly inclined, and the slider of the potentiometer is increased with the increase of the inclination angle of the lever. The contact point between the and the annular resistor moves, and the speed of the electric motor increases in response to the tilt angle of the lever.

[0015]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a drawing corresponding to FIG. 8, and shows a part of the operation panel. 2 is a front view of FIG. 1, FIG. 3 is a relationship diagram of a contact configuration of a potentiometer and a cam switch of the embodiment, and FIG. 4 is a swing motor control inverter control circuit diagram of the embodiment. In FIGS. 1 and 2, a potentiometer 33 with an intermediate tap 35 (see FIG. 3) is attached to one side of a mounting frame 34 of the universal lever 16 about an axis that rotates by an AA ′ direction operation. A cam switch 32 is attached to the other side. The potentiometer 33 has a slider 36 (see FIG. 3) attached to a rotating shaft that rotates by moving the universal lever 16 in the AA ′ direction, and the slider 36 slides on the annular resistor 37 ( 3 (see FIG. 3) is attached to the case of the potentiometer 33. On the contrary, it is possible to provide the slider 36 on the case side of the potentiometer 33 and the resistor 37 on the rotary shaft side. In the cam switch 32, the movable contact is attached to the rotating shaft that rotates by moving the universal lever 16 in the AA 'direction, and the arc-shaped fixed contact is attached to the case of the cam switch, as in the conventional case. As shown in Fig. 3, the contact points 32A and 32B (see Fig. 4) of the cam switch are open in the range of 3 degrees to the left and right of the neutral position of the universal lever 16 and a total of 6 degrees, and the cam switch contacts 32A and 32B (see Fig. 4) are open to the left or right by 3 degrees or more. When moved, the contact 32B or 32A closes. Further, in the potentiometer 33, the slider 36 moves in accordance with the size of the universal lever 16 in the AA ′ direction inclining angle (maximum 30 degrees on each side), and the slider 36 from the intermediate tap 35 moves. A control signal having a magnitude proportional to the amount of movement is output, and the inverter 31 sets the lowest frequency when the slider 36 is at the position of the intermediate tap 35 and the highest frequency at the maximum rotation angle. In addition, the turning motor 6B is driven at a frequency corresponding to the output of the potentiometer 33.

Therefore, if the universal lever 16 is now moved in the A direction, the contact 32A is closed, the electromagnetic contactor SR of FIG. 4 is excited, and the contacts SR1 and SR2 are closed. The start signal input terminal h is connected to the start signal self-holding relay terminal a, whereby the inverter 31 is started, and the forward / reverse signal input terminal e is connected to the control circuit common terminal c via the contact SR4. As a result, the inverter 31 determines the phase rotation direction of the output so that the right turn is performed. At the same time, the signal from the potentiometer 33 is applied to the inverter 31 via the contact SR3, and the output of the frequency corresponding to the output of the potentiometer 33 is applied to the swing motor 6B from the output terminals U, V, W, and the swing motor 6B. Is driven.

Therefore, when the universal lever 16 is tilted in the direction A, the turning motor 6B rotates at a turning speed according to the tilt angle of the lever 16, and when the lever 16 is fully tilted (notch angle 30 ° in this example). ), The speed reaches the maximum. On the contrary, if the lever 16 is tilted in the A'direction, the left turn is likewise made at the speed corresponding to the inclination angle of the lever 16.

Further, by operating the lever 16 in the B or B ′ direction, the jib 5 is undulated. Further, since it is a universal lever, if the lever 16 is moved in the direction between the directions A-A 'and B-B', simultaneous turning and undulating operations are possible.

Although the above description has been given of an example in which only the swing operation is controlled by the inverter, the inverter control of the motor can be applied to the hoisting and the undulation. Therefore, as in the embodiment, there are three motors (swing and undulation). Even if some or all of the windings are controlled by an inverter, by adopting the same structure for each, continuous and continuously variable shifting of the motor is possible. Further, although the jib crane has been described in the above-mentioned embodiment, also in another crane using an electric motor as a power source, for example, an Arai crane, the operations of hoisting, traveling and traversing are performed by two sets of universal levers. It can be similarly applied by taking charge.

[0020]

[Effect of device]

 As described above, the crane control panel according to the present invention can open and close the power electric motor circuit and control the speed of the electric motor by operating one universal lever. It is possible to start, stop, and control the speed of the crane with one hand, which makes the operation extremely easy and, of course, either the rotating shaft or the potentiometer case covering the rotating shaft can be used to adjust the potentiometer. Since the slider of the motor is provided and the annular resistor of the potentiometer is provided on the other side, the configuration of the potentiometer is compact and the universal lever can be easily attached. Moreover, even if the universal lever is attached, the operation panel is so large. It does not change, which is advantageous in manufacturing.

Further, since the universal lever is used, by providing a motor circuit opening / closing switch and a controller around two axes for one universal lever, one universal lever can be operated. That is, it is possible to open / close two sets of inverter-controlled power circuits and control the speed with one hand, and the operability is improved together with the compact operation panel as described above.

Further, by providing two universal levers having such a configuration, it becomes possible to open / close and speed control four inverter-controlled power circuits with both hands.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a control panel of a crane showing an embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a relationship diagram of a contact configuration of a potentiometer and a cam switch of the embodiment.

FIG. 4 is a circuit diagram of inverter control of the embodiment.

FIG. 5 is a side view showing a crane as an example to which the present invention is applied.

FIG. 6 is a circuit diagram showing a control circuit of a conventional pole-changing type swing motor.

FIG. 7 is a perspective view showing a conventional operation panel.

8 is a perspective view showing a part of FIG. 7. FIG.

9 is a relationship diagram of a contact structure of the cam switch of the lever of FIG.

FIG. 10 is a circuit diagram of a conventional inverter control.

FIG. 11 is a diagram showing a conventional power circuit control operation panel including inverter control.

[Explanation of symbols]

 16 universal lever 21 cam switch 32 cam switch 32A, 32B cam switch contact 33 potentiometer 34 mounting frame 35 intermediate tap 36 slider 37 annular resistor

Claims (1)

[Scope of utility model registration request] 1. An electric crane that uses an electric power motor for inverter control in part or all of a power plant and is equipped with a potentiometer as a means for generating an inverter control signal. An electric motor circuit opening / closing switch having a universal lever as an operating means, and having a contact opened coaxially with a rotary shaft rotated by the operation of the universal lever at a neutral position of the lever and closed at a certain inclination angle or more. An electric crane, wherein the rotary shaft and a potentiometer case covering the rotary shaft are provided with a potentiometer slider and the other is provided with a potentiometer annular resistor.