JPS5842323Y2 - Conveyor protection and feed rate control device - Google Patents

Description

[Detailed description of the invention] The invention detects the load current of the conveyor drive motor,
The present invention relates to a device that controls the flow rate of conveyed materials, prevents overload of a drive motor, and protects a conveyor.

Conventionally, in order to control the feed rate of conveyed objects on a conveyor,
The volume of the transported object is detected and converted into weight, and the supply amount is controlled based on the weight.

Therefore, this method has the disadvantage that the apparatus is complicated.

In addition, a protection device for preventing overload of the conveyor must be installed separately from the device for controlling the flow rate, which further complicates the entire device.

Therefore, the present invention provides a feed rate control device that also serves as a protection device that eliminates the above-mentioned drawbacks.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in the block diagram of Fig. 1, the device of the present invention inputs a load signal proportional to the load current of the motor M from a current transformer H attached to the main circuit of the motor M1 that drives the conveyor. It consists of a control circuit A and an overload prevention circuit B.

The control circuit A generates a control signal a for on/off controlling the electric motor M of the continuous feeding device 2 that supplies the conveyed material to the conveyor.
When a current exceeding the load current value corresponding to the feed rate setting upper limit flows in the main circuit, the contact of the electromagnetic switch MC inserted in the power supply circuit of the motor M is opened. At the same time, when a current equal to or less than the load current I corresponding to the feed rate setting lower limit flows, a control signal a is output that closes the contact of the electromagnetic switch MC.

In addition, the overload prevention circuit B holds the contacts of the electromagnetic switch MC inserted in the main circuit of the conveyor drive motor M open, and also opens the contacts of the electromagnetic switch MC to stop the continuous feeding device 2.
This outputs a stop signal to keep the motor in a stopped state.

In order to maintain the continuous supply device 2 in a stopped state, in the embodiment, a stop signal A is inputted to the control circuit A, and the control signal A that opens the contact of the electromagnetic switching gIC is self-maintained.

Next, the operation of the device of the present invention will be explained.

First, when the conveyor drive motor M and the motor M of the continuous feeding device are started, a starting current flows through the motor M for a time T, but during that time, the outputs of circuits A and B are kept at a low level by an interlock circuit (not shown). There are up to 1 (Figure 2).

Next, when the conveyor and continuous feeding device 2 are in steady operation and the amount of conveyed material increases, the load on the conveyor drive motor M increases and its main circuit current reaches the value . Outputs control signal a.

Then, the contact of the electromagnetic switch MC inserted into the main circuit of the electric motor M of the continuous feeding device 2 is opened, the continuous feeding device 2 is temporarily stopped, and the conveyance amount of the conveyor 2 is reduced.

When the conveyance amount of the conveyor 2 decreases and the value of the load current of the motor M decreases by I1, the control signal a of the circuit A becomes a low level, the contact of the electromagnetic switch MC closes, and the conveyed object is switched from the continuous feeding device 2 to Refeed the conveyor.

In this way, circuit A is constructed such that the load current value of conveyor 1 is 1.
A control signal a is outputted so that the constant supply of the conveyed object is maintained between and (2).

Next, when an abnormal overload is applied to the conveyor and the load current value of the motor M1 exceeds the above-mentioned ■1 and reaches I3 or more, the stop signal of the overload prevention circuit B changes from a low level to a high level, and the motor M1 stops. The signal is self-maintained.

Then, the signal switch opens the contact of the electromagnetic switch MC of the motor M1 to stop the conveyor from overloading, and at the same time holds the output a of the circuit A at a high level of 1, and the continuous feeding device 2 is also stopped. maintain it.

The continuous feeding device 2 of the present invention is not limited to the Scheldt type feed conveyor shown in FIG. 1, but may be a bucket type conveyor or a hopper having an opening/closing shutter at the bottom.

Further, the object to be transported may be a single object or a granular object.

In addition, in the above embodiment, in order to stop the electric motor M due to overload, a stop signal is input to the circuit A, and the electric motor M is maintained in a stopped state via the circuit A.The present invention is limited to the above embodiment. It is also possible to directly control the electromagnetic switch MC using the stop signal without the need for a stop signal.

Note that the control circuit A and the overload prevention circuit B can be easily constructed using ordinary relays and the like, so detailed explanations thereof will be omitted.

As is clear from the above description, the device of the present invention can control the feed rate of the continuous conveyance device 2 on and off in response to increases and decreases in the load current of the electric motor M, thereby making it possible to keep the conveyance amount constant.

When an overload is applied, the conveyor device 2 and the conveyor are maintained in a stopped state to protect the conveyor device,
This has the effect of preventing damage to the conveyed items that would occur if only the conveyor stopped.

In addition, if this device is installed inside the specified casing, the alternator H
By simply providing the main circuit of the conveyor drive motor M and connecting the output wiring to the electromagnetic switch MC9MC2, conveyor feed rate control and overload prevention can be achieved, which has the effect of simplifying the wiring of the control system. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram;
FIG. 2 is an explanatory diagram of the operation. 1...Conveyor, 2...Continuous supply device, A...Control circuit, B...Overload prevention circuit, M...Conveyor Drive motor, M...
...Electric motor, H...Current transformer, MC, MC2...
····electromagnetic switch.

Claims (1)

[Scope of utility model registration request] A continuous feeding device that inputs a load signal proportional to the main circuit current of the conveyor drive motor and supplies the conveyed object to the conveyor is operated so that the main circuit current is within the range between the upper limit value of the conveyance rate setting of the conveyed object and the feed rate setting 'UJI value. A control circuit outputs a control signal for on/off control as shown in FIG. A conveyor protection and feed rate control device having an overload prevention circuit that outputs a stop signal to maintain the conveyor.