JPH06247528A - Body pushing device - Google Patents

Abstract

PURPOSE:To prevent erroneous operation of a danger preventing mechanism due to a decrease in temperature by largely changing an allowable value in a determining circuit when the temperature around a body push-feed mechanism. CONSTITUTION:A subtracting circuit 23 calculates a difference between an actual movement of a pusher member 14 and a theoretical movement calculated by a CPU 16, and a determining circuit 24 compares the difference with an allowable value. If the difference exceeds the allowable value, the determining circuit 24 delivers a stopping signal for stopping a motor 2. At this time, a temperature sensor 31 measures a temperature around a body push-feed mechanism 1, and an allowable value determining circuit 32 sets the allowable value in the determining circuit 24 over a wide range when the temperature is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object pushing apparatus used in an automatic packing apparatus for products in a manufacturing factory, an automatic packing apparatus for goods provided in a checkout counter of a store, and the like.

[0002]

2. Description of the Related Art Automatic packing machines and automatic packing machines use an object pushing mechanism that converts the rotational movement of a motor into a linear reciprocating movement of a pushing member and pushes out an object (product, product, etc.) by the pushing member. Has been done.

FIG. 3 is a block diagram showing a conventional object pushing mechanism 1 of this type and its control system. Object pushing mechanism 1
Attaches the first pulley 5 attached to the output shaft 4 of the gear head 3 for decelerating the forward / reverse rotation motor 2 above the starting end P of the object transfer path 6 and above the end Q of the object transfer path 6. Install the 2nd pulley 7. Then, the wire 8 is bridged between the pulleys 5 and 7, and the rail 9 is installed along the wire 8. The rail 9 holds the carriage 10 slidably, and a part of the carriage 10 is fixed to the wire 8. The carriage 10 mounts the push plate 12 via the arm 11.

Here, the carriage 10, the arm 11 and the pushing plate 12 constitute a pushing member 14 for pushing the object 13 on the object transfer path 6 from the starting end P to the ending end Q.

A push plate 12 of a push member 14 is attached to the rail 9.
Is located at the starting end P of the object transfer path 6, a reset signal R
A position sensor 15 that outputs S is attached.

A CPU (central processing unit) 16 which is the center of the control system sends an enable signal EN and a rotation direction signal DR to a motor driver 18 based on a control program stored in a memory 17 to rotate the motor 2 in a normal direction. Control reversal. The motor driver 18 applies the drive pulse PS from the pulse oscillator 19 to the motor 2 in response to the input of the enable signal EN and the rotation direction signal DR to rotate the motor 2 normally or reversely.

An encoder 20 is attached to the motor 2, and an output signal from the encoder 20 is encoded by an encoding circuit 21 and counted by a counter 22 to constantly detect the actual movement amount of the pushing member 14. . Here, the encoder 20, the encoding circuit 21, and the counter 22 constitute an actual movement amount detecting means.

On the other hand, the CPU 16 controls the pressing member 1 determined by the oscillation cycle of the drive pulse PS from the pulse oscillator 19.
4 and the moving time of the pressing member 14 corresponding to the output time of the enable signal EN, the theoretical moving amount of the pressing member 14 is constantly calculated, and the subtraction circuit 23 uses the actual moving amount detecting means. CPU1 and the actual amount of movement detected by
The difference from the theoretical movement amount calculated in 6 is constantly calculated, and the difference data is output to the determination circuit 24. The judgment circuit 24 judges whether or not the difference data from the subtraction circuit 22 exceeds a certain allowable value. If the difference data exceeds the certain allowable value, the stop signal S
T is applied to the AND gate 25 to invalidate the enable signal EN output from the CPU 16 to the motor driver 18. Here, the CPU 16, the subtraction circuit 23, the determination circuit 24, and the AND gate 25 constitute a danger prevention unit.

The stop signal ST from the determination circuit 24 is also supplied to the CPU 16, and the CPU 16 outputs a display control signal to the display driver 27 to cause the display 26 to display an abnormal stop display in response to the input of the stop signal ST. .

The counter 22 and the CPU 16 perform a reset operation when the reset signal RS from the position sensor 15 is input.

In the object pushing apparatus having such a structure, the pushing plate 12 of the pushing member 14 is provided with the starting end P of the object transfer path 6.
When a push command for the object 13 is input to the CPU 16 from the outside in the state of being positioned at, the CPU 16 outputs a rotation direction signal DR instructing normal rotation to the motor driver 18 together with the enable signal EN. As a result, the motor 2 normally rotates in synchronization with the drive pulse PS from the pulse oscillator 19. Then, the first pulley 5 rotates in the direction of arrow A in the figure, and the wire 8 moves in the direction of arrow B in the figure. As a result, the carriage 10 fixed to the wire 8 is moved to the arrow B in the figure.
And pushes the object 13 on the object transfer path 6 toward the pushing plate 12
Press with.

At this time, the CPU 16 calculates the theoretical value of the moving amount from the moving speed and moving time of the pushing member 14, and the theoretical value of the moving amount is the moving distance from the start end P to the end Q of the object transfer path 6. If it corresponds to, the rotation direction signal DR
Is changed from the forward rotation direction to the reverse rotation direction. This causes the motor 2 to rotate in the reverse direction. Then, the first pulley 5 rotates in the direction opposite to the arrow A direction in the figure, and the wire 8 moves in the direction opposite to the arrow B direction in the figure. As a result, the carriage 10 moves backward.

When the push plate 12 returns to the starting end P of the object transfer path 6, the position sensor 15 outputs a reset signal RS to reset the CPU 16 and the counter 22.

During the rotation of the motor 2, the signal from the encoder 20 attached to the motor 2 is encoded by the encoder circuit 21 and counted by the counter 22, so that the actual movement amount of the pushing member 14 is constantly detected. There is. Then, the subtraction circuit 23 constantly calculates the difference between the actual movement amount and the theoretical movement amount calculated by the CPU 16, and the judgment circuit 24 constantly compares the difference with a preset allowable value. It is being appreciated.

Here, when the object 13 cannot be pushed by being pinched by something during the pushing of the object 13 or the pressing member 14 cannot move due to an abnormality of the wire 8 or the rail 9, the pressing member 14 is actually moved. The difference between the actual movement amount and the theoretical movement amount gradually increases and eventually exceeds the allowable value. Then, in order to prevent danger, the stop signal S is sent from the determination circuit 24.
T is output to the AND gate 25 and the CPU 16.

As a result, the enable signal EN from the CPU 16 to the motor driver 18 becomes invalid and the motor 2
Rotation is stopped. In addition, information indicating an abnormal stop is displayed on the display 26.

[0017]

As described above, in the conventional object pushing apparatus of this type, the rotational movement of the motor 2 is converted into the linear reciprocating movement of the pushing member 14 to move the object 13 to the starting end P of the transfer path 6. It is configured to be pushed and transferred from the end to the end Q. Then, the actual movement amount of the pushing member 14 is constantly detected, and when the difference between the actual movement amount and the theoretical movement amount calculated by the CPU 16 exceeds a certain allowable value, it is judged that an abnormality has occurred. By stopping the rotation of the motor 2 quickly, the danger is prevented.

However, when the ambient temperature of the object pushing mechanism 1 is low, such as in winter, the viscosity of the lubricating oil in the gear head 3 and the like becomes higher than in the high temperature period, and the load on the motor 2 increases. Then, when the object 13 is pushed out, a high load is applied to the motor 2 and the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 becomes large, exceeding a certain allowable value, and no abnormality occurs. Nevertheless, the danger prevention mechanism worked and the motor 2 sometimes stopped.

Although it is possible to set the permissible value to a constant large value in order to eliminate such a problem, in such a case, detection of an abnormality is delayed even at high temperature, which causes a decrease in safety and is not suitable for practical use. Absent.

Therefore, according to the present invention, when the ambient temperature of the object pushing mechanism is low, the allowable value to be compared with the difference between the actual moving amount and the theoretical moving amount of the pushing member is changed to a large degree, thereby reducing the risk of temperature drop. To prevent malfunction of the prevention mechanism,
It is an object of the present invention to provide an object pushing device capable of improving reliability without impairing safety.

[0021]

SUMMARY OF THE INVENTION According to the present invention, an object pushing mechanism for converting a rotational movement of a motor into a linear reciprocating movement of a pushing member to push and convey an object by the pushing member, and an actual moving amount of the pushing member are detected. The difference between the movement amount detection means and the actual movement amount detected by this detection means and the theoretical movement amount obtained by calculation is calculated, and the motor is stopped when the difference is larger than a predetermined allowable value. In an object pushing device provided with a danger preventing means for controlling the operation of the pushing member to stop, a temperature measuring means for measuring an ambient temperature of the object pushing mechanism, and an allowance in the danger preventing means based on the temperature measured by the measuring means. And a permissible value determining means for variably setting the value.

[0022]

According to the present invention having such a structure, when the ambient temperature of the object pushing mechanism is low and the load on the motor is large,
When pushing out an object, a high load is applied to the motor and the difference between the actual movement amount of the pushing member and the theoretical movement amount becomes large.
When the temperature is low, the allowable value determining means sets an allowable value larger than this difference to prevent malfunction of the danger prevention mechanism.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those of the conventional device shown in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

That is, the object pushing mechanism 1 decelerates the rotational movement of the motor 2 by the gear head 3 and pushes the pushing member 14 by the wire 8 bridged between the first and second pulleys 5 and 7.
This push member 1 is a mechanism for converting into linear reciprocating motion of
4 linearly reciprocates along the rail 9 to move the object transfer path 6
The object 13 is pushed out and transferred from the start end P to the end Q.

The actual movement amount detecting means composed of the encoder 20, the encoding circuit 21 and the counter 22 is
The actual amount of movement of the pushing member 14 is constantly detected.

CPU 16, subtraction circuit 23, determination circuit 24
And the hazard prevention means composed of the AND gate 25 is C
The subtraction circuit 23 calculates the difference between the theoretical movement amount of the pushing member 14 calculated by the PU 16 and the actual movement amount detected by the actual movement amount detecting means, and this difference exceeds a predetermined allowable value. When the determination circuit 24 determines that the stop signal S
By outputting T to the AND gate 25, the enable signal EN supplied from the CPU 16 to the motor driver 18 is invalidated, the motor 2 is stopped and controlled, and the operation of the pushing member 14 is stopped.

The stop signal ST from the judgment circuit 24 is the CPU
The information is also supplied to 16 and the information indicating the abnormal stop is displayed on the display 26.

The CPU 16 operates according to the control program stored in the memory 17. Further, the CPU 16 and the counter 22 are reset by a reset signal RS output from the position sensor 15 when the push plate 12 of the push member 14 is located at the starting end P of the object transfer path 6.

The above configuration is similar to that of the conventional device.

The object pushing apparatus of this embodiment is provided with the temperature sensor 31 as a temperature measuring means for measuring the ambient temperature of the object pushing mechanism 1. Then, the output signal of the temperature sensor 31 is input to a permissible value determining circuit 32 as permissible value determining means, and the permissible value determining circuit 32 variably sets the permissible value of the determination circuit 24 in the danger preventing means based on the measured temperature. This is the configuration.

The allowable value determination circuit 32 is provided with a sensor measured temperature T (° C.)-Allowable value D (cm) conversion table having the characteristics shown by the solid line M in FIG. The corresponding allowable value D is read from the above table and output to the determination circuit 24. Therefore, when the measured temperature T is 10 ° C. or higher, the allowable value D is constant at 1 cm, and when the measured temperature T is 10 ° C. or lower, the allowable value D is changed by 1 mm each time the temperature decreases by 1 ° C.

The judging circuit 24 compares the difference between the actual moving amount and the theoretical moving amount of the pushing member 14 obtained by the subtracting circuit 23 with the allowable value D input from the allowable value determining circuit 32. Then, when the difference exceeds the allowable value, the stop signal ST
Is output.

In this embodiment having such a structure, the allowable value D is fixed at 1 cm when the ambient temperature of the object pushing mechanism 1 measured by the temperature sensor 31 is 10 ° C. or higher. Therefore, if the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 obtained by the subtraction circuit 23 is within 1 cm, the danger prevention mechanism does not work, and if it exceeds 1 cm, the danger prevention mechanism works and the judgment circuit 24 stops. The signal ST is output and the rotation of the motor 2 is stopped.

Normally, when the ambient temperature is 10 ° C. or higher, the difference between the actual movement amount of the pushing member 14 and the theoretical movement amount is 1 cm.
When the object 13 is caught by something and cannot be pushed, or the wire 8 or the rail 9 is abnormal,
In the case of such an abnormal situation, the rotation of the motor 2 is stopped immediately and the pushing member 14 is stopped. Therefore, the damage of the object 13 and the occurrence of danger due to the abnormal situation are prevented in advance. To be done.

On the other hand, when the ambient temperature is low, for example, 0 ° C., the allowable value D is changed to 2 cm. Therefore, if the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 obtained by the subtraction circuit 23 is within 2 cm, the danger prevention mechanism does not work, and if it exceeds 2 cm, the danger prevention mechanism works and the judgment circuit 24 stops. The signal ST is output and the rotation of the motor 2 is stopped.

In general, when the ambient temperature of the object pushing mechanism 1 becomes low in winter, the viscosity of the lubricating oil in the gear head 3 and the like becomes higher and the load on the motor 2 becomes heavier than when the temperature is high. Then, when the object 13 is pushed out, a high load is applied to the motor 2 and the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 becomes large, which may exceed 1 cm.

Conventionally, in order to keep the accuracy of abnormality detection high, the allowable value D is always fixed in the vicinity of 1 cm as shown by the characteristic indicated by the alternate long and short dash line N in FIG. Therefore, when the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 becomes large due to the decrease in the ambient temperature, the difference exceeds the allowable value D, and the danger prevention mechanism operates and the motor 1 operates. There was a problem that the rotation of was stopped.

On the other hand, in this embodiment, the ambient temperature is 10
When the temperature becomes lower than ℃, the allowable value D is gradually increased as the temperature lowers. Therefore, the difference between the actual movement amount and the theoretical movement amount of the pushing member 14 becomes 1 cm or more due to the lowering of the ambient temperature. However, the allowable value D is rarely exceeded.

Therefore, according to this embodiment, it is possible to prevent the danger prevention mechanism from malfunctioning due to a decrease in ambient temperature, so that the object 13 can be reliably pushed even at a low temperature. Moreover, since the allowable value can be set low when the ambient temperature is relatively high, the accuracy of the danger prevention mechanism can be kept high. As a result, it is possible to provide an object pushing device that is excellent in reliability and safety, and this object pushing device is used for automatic packaging of products in manufacturing plants and automatic packaging of products provided at checkout counters of shops. The effect is great when it is used in a device or the like.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the allowable value determination circuit 32 is designed so that the allowable value D is gradually and largely changed in proportion to the decrease of the measured temperature T in the low temperature, but the allowable value is gradually increased as the measured temperature T is decreased. You may design so that D may change a lot. Further, the allowable value determination circuit 32 may be configured to calculate the allowable value D corresponding to the measured temperature T using an arithmetic expression and output it to the determination circuit 24.

In addition, a plurality of temperature sensors are attached to the object pushing mechanism 1
It is also possible to arrange it at various places around and to determine the allowable value from the average value of the temperature measured by each sensor. Of course, various modifications can be made without departing from the scope of the present invention.

[0042]

As described above in detail, according to the present invention, the ambient temperature of the object pushing mechanism is measured by the temperature sensor, and the actual moving amount and the theoretical moving amount of the pushing member are calculated based on the measured temperature. Since the allowable value to be compared with the difference between is set to be variable, the allowable value can be changed significantly when the ambient temperature of the object pushing mechanism is low to prevent malfunction of the danger prevention mechanism due to temperature drop and to improve safety. It is possible to provide an object pushing device that can improve reliability without damaging it.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a sensor measurement temperature-tolerance value conversion table provided in the tolerance value determination circuit of the apparatus of the embodiment.

FIG. 3 is a block diagram showing a configuration of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Object pushing mechanism, 2 ... Motor, 14 ... Pushing member, 16 ... CPU, 20 ... Encoder, 21 ... Encoding circuit, 22 ... Counter, 23 ... Subtraction circuit, 24 ... Judgment circuit, 31 ... Temperature sensor, 32 ... Allowable value determination circuit.

Claims (1)

[Claims] 1. An object pushing mechanism for converting a rotational movement of a motor into a linear reciprocating movement of a pushing member to push and convey an object by the pushing member, and an actual movement amount detecting means for detecting a movement amount of the pushing member. The difference between the actual movement amount detected by the detection means and the theoretical movement amount obtained by calculation is calculated, and when the difference is larger than a predetermined allowable value, the motor is stopped and controlled to operate the pushing member. In an object pushing device provided with a danger preventing means for stopping, a temperature measuring means for measuring an ambient temperature of the object pushing mechanism, and a permissible value in the danger preventing means is variably set based on a temperature measured by the measuring means. An object pushing device comprising: a tolerance determining means.