JPH0353837Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to an overheat prevention circuit that prevents a clutch brake and its peripheral devices from overheating during intermittent operation of a press machine.

[Conventional technology]

When the press equipment is operated intermittently, the clutch brake and its peripheral equipment generate heat each time the operation is interrupted.
The accumulated heat is released over time. Therefore, in order to operate the press machine safely during intermittent operation, it is necessary to operate within a range in which the amount of heat generated per intermittent operation does not exceed the amount of heat dissipated within one stroke time, and the heat exceeding the allowable limit is released from the clutch brake. It is necessary to prevent it from accumulating in the surrounding areas. FIG. 3 shows the relationship between the number of continuous strokes and the allowable number of intermittent strokes, with the horizontal axis showing the number of continuous strokes (in SPM) and the vertical axis showing the allowable number of intermittent strokes (in SPM). Now, the amount of heat generated per one intermittent operation is approximately proportional to the kinetic energy, and the greater the number of continuous strokes (that is, the faster the rotational speed), the greater the amount of heat generated per one intermittent operation. In the region where the number of continuous strokes from the origin to point P in Figure 3 is small, the amount of heat generated per one intermittent stroke is sufficiently smaller than the amount of heat dissipated per one stroke, so the allowable number of intermittent strokes matches the number of continuous strokes. , when the number of continuous strokes exceeds point P, the amount of heat generated per one stroke becomes larger than the amount of heat dissipated within one stroke time, so it becomes necessary to increase the interval time for each stroke. As the number increases, the allowable number of intermittent strokes decreases. Therefore, conventionally, as shown in Figure 3, graphs and lists of similar contents were written in instruction manuals, etc.
It urged caution to operate intermittently within this range.

[Problem that the invention attempts to solve]

However, even if intermittent operation exceeding the allowable intermittent stroke number is performed, the press equipment will not immediately break down, so in actual work,
There was no guarantee that the instructions in the instruction manual would always be followed, and as a result of continued unreasonable operation, serious accidents could occur due to overheating, such as seizure of the crankshaft and wear of the clutch brake.

[Means to solve the problem]

The present invention has been developed in view of the current situation, and is intended to prevent overheating of a press machine by making it impossible to perform intermittent operation exceeding the allowable number of intermittent strokes determined by the number of continuous strokes during intermittent operation. The purpose is to provide circuits. The overheating prevention circuit for the press apparatus of the present invention achieves the above object with the following configuration. (1) Provide a timer that generates an output when the set time elapses after being activated by the set point stop. (2) By giving a start signal to the press device based on the logical product of the output of the operation switch on the operation panel and the output of the timer, the press device cannot be restarted until the set time of the timer has elapsed after the set point has stopped. Make it impossible. (3) When a continuous stroke number signal indicating the rotational speed of the press device is input to the timer and the press device is operated at the speed indicated by the input continuous stroke number signal, the occurrence of intermittent strokes occurs intermittently longer than the time required for one stroke. When the time required to dissipate heat is long, the interval time for heat dissipation is forced by variably setting the timer for at least the difference between the two times based on the input continuous stroke number signal. to be established.

[Effect]

In other words, according to the overheating prevention circuit of the present invention, as the number of continuous strokes increases, the timer setting time can be increased accordingly, so that the heat generated during intermittent operation can be used for the next intermittent operation. You can take enough interval time to dissipate the heat until then.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 is an expanded connection diagram showing parts directly related to the present invention extracted from the press control circuit, where lines 1 and 2 are the press starting circuit, line 3 is the clutch brake excitation circuit, and line 2 is the press starting circuit. 4,
Line 5 is restart prevention circuit, line 6, line 7
1 and 2 respectively show timer circuits for time-limited operation. Further, in the drawings, a relay coil and a contact point corresponding to the relay coil are given the same reference numerals. First, 1 is the A contact of the operation button, 2 is the A contact 1
3 is the A contact of the operation button which is connected to the A contact 1, and 4 is the B contact which is connected to the A contact 3 and connected to the B contact 2. The A contact 6 of the relay coil 5, which is connected with the A contacts 1 and 3 of the operation button, is connected with the solenoid valve 7 of the clutch brake, and when the press is started, the relay coil 5 is energized and its A is connected.
When the contact point 6 is made, the solenoid valve 7 is energized. In addition, in line 3, the solenoid valve 7 and the A contact 6 for excitation, the A contact 8 of the rotary cam switch for stopping the set point, the A contact 9 of the rotary cam switch for safe operation, and the self-holding of the relay coil 5. The solenoid valve 7 is energized by the line 3 circuit after the A contacts 8 and 9 are closed after the press is started. In addition, the operating angle of each rotary cam switch is
They are shown all at once in the figure, and the shaded portion in FIG. 2 is the angle being made. That is, the A contact 8 of the rotary cam switch for stopping at the set point is made when the crank angle of the press device is 5 degrees, and is broken at an angle just before the top dead center (330 degrees in this embodiment). In addition, the angle of the A contact 9 of the rotary cam switch for safe driving is at an angle just before the bottom dead center where there is no room for the operator to put his hand (in this example, 150
Make at an angle (330 degrees in this example) and break at an angle just before top dead center (330 degrees in this example). Now, as mentioned above, the starting relay coil 5 in the line 1 circuit is energized when the A contacts 1 and 3 of the operation button are made, but there is a restart prevention relay in the line 1 circuit. The B contact 12 of the coil 11 and the A contact 14 of the restart prevention relay coil 13 are AND-connected, and therefore, the fact that both the B contact 12 and the A contact 14 are closed excites the relay coil 5. It is a prerequisite for Of these, the B contact 12 is connected to the relay coil 11 of line 2, which is the activation source, with the B contacts 2 and 4 of the operation button, so the B contacts 2 and 4 break in conjunction with the ON of the operation button. When the relay coil 11 is demagnetized by doing so, it is made. That is, the making of the B contact 12, which is one of the conditions for excitation of the relay coil 5, is established by pressing the operation button. On the other hand, the relay coil 13 for making the A contact 14 includes: the A contact 15 of the relay coil 11 - the B contact 16 of the relay coil 5 - the B contact 17 of the rotary cam switch for safety 1 stroke - the rotary cam switch for setting point stop. The A contact 18 of the cam switch is AND-connected with the A contact 19 of the rotary cam switch for preventing restart and the A contact 20 of the on-delay timer, which is a feature of this embodiment. Furthermore, line 4 B
The contact 21 is a contact linked to a switch for selecting one safety stroke, and is broken when one safety stroke is selected as the operation mode, so it is separated from the excitation circuit of the relay coil 13. As is clear from the explanation of the operation described later and FIG. 2, when the press device is stopped at the set point, the A contact 15 - the B contact 16 - the B contact 17 -
A contacts 18-A contacts 19 are all made,
Therefore, the fact that the A contact 20 of the on-delay timer is closed is a condition for exciting the relay coil 13, and in turn, a condition for exciting the relay coil 5. In addition, the A contact point 22 of line 5
is for self-holding of the relay coil 13. Therefore, in this embodiment, by linking the delay time of the timer circuit 23 for time-limited operation of the A contact 20 to the number of consecutive strokes, it is possible to restart the press device after an interval time corresponding to the number of consecutive strokes has elapsed. I'm doing it like that. Specifically, the timer circuit 23 is AND-connected with the A contact 19 of the rotary cam switch for preventing restart, the A contact 24 for selecting one safety stroke, and the B contact 25 linked to the relay coil 5. 19
As shown in FIG. 2, the angle is adjusted to break during a period of, for example, 260 degrees to 280 degrees. Therefore,
The timer circuit 23 is reset by breaking the A contact 19 for restart prevention, and after the A contact 19 is made, the relay coil 5 is demagnetized and the B contact 25 is closed.
is started when the is made. A speed designation signal SPM for designating the number of continuous strokes applied from, for example, a speed adjustment switch (not shown) is applied to the timer circuit 25, and the delay time is controlled by this speed designation signal SPM. Note that the relay coil 26 and A contact 27 are for self-holding. Next, the operation of this embodiment will be explained with reference to the above matters. First, the timer circuit 23 receives a speed designation signal corresponding to the setting position of an operating speed adjustment switch (not shown).
SPM has been added. Further, during the first safety stroke, a safety first stroke selection switch (not shown) is turned on, and in conjunction with this, the A contact 24 is made and the B contact 21 is broken. Further, when the press device is stopped at the set point, the crank angle is at the set point of 0 degrees, and the A contact 19 of the rotary cam switch for preventing restart is closed. Furthermore, since the relay coil 5 is demagnetized when the press device is stopped, its B contact 25
is wearing makeup. Therefore, A contact 10 - A contact 24 - B contact 25
The relay coil 26 is excited along the path and self-held at its A contact 27. At this time, the timer circuit 23
is also set, the timer circuit 23 starts a timing operation and closes the A contact 20 after a delay time determined in response to the speed designation signal SPM. When the press device is stopped at the set point, the A contact 18 of the rotary cam switch for setting point stop, the B contact 17 of the rotary cam switch for safety 1 stroke, and the B contact 16 of the relay coil 5 are closed. In addition, when the operation button is not pressed, the A contact 15 of the relay coil 11 is closed, so the relay coil 13 is energized as the A contact 20 of the on-delay timer is closed, and the A contact 22 is closed. self-maintained by Therefore, the A contact 14 of line 1 is also made. When the operator presses the operation button in this state, the B contacts 2 and 4 break, so the relay coil 11 is demagnetized and the B contact 12 of the line 1 is made. The A contact 14 is made as described above with the excitation of the relay coil 13, and
Since the A contacts 1 and 3 are made by turning on the operation button, the relay coil 5 is energized. By energizing the relay coil 5, the A contact 6 of the line 3 is made, the solenoid valve 7 of the clutch brake is energized, and the operation of the press is started. In addition, until the crank angle reaches 150 degrees and the A contact 9 of the rotary cam switch for safe 1st stroke is closed, the solenoid valve 7 is in the A contact 1 - A contact 3 - B contact 12 - A contact 14 - A contact. 6, the press device immediately stops when the operator releases the operation button and the A contacts 1 and 3 break. Now, when the crank angle reaches 150 degrees, the A contact 9 of the rotary cam switch for safety 1 stroke is closed, and the A contact 8 of the rotary cam switch for setting point stop is closed when the crank angle is between 330 degrees and 5 degrees. Since everything else is made, solenoid valve 7 has A contact 8-A.
The press will continue to rotate even if the operator releases the operation button because the press will be energized along the path of contact 9-A contact 10 and A contact 6. When the press continues to rotate and the crank angle reaches 260 degrees, the A contact 19 of the rotary cam switch for preventing restart breaks, so relay coil 1
3 is demagnetized, and at the same time the timer circuit 23 is also reset. When the crank angle reaches 280 degrees, the A contact 19 is closed, but since the B contact 25 of the relay coil 5 is broken while the press is in operation, the timer 23 remains reset. Now, after the A contact 14 breaks due to the demagnetization of the relay coil 13, the press device
Since the circuit is operated, the crank angle is
When the temperature reaches 330 degrees and the A contact 8 of the rotary cam switch for stopping the setting breaks, the solenoid valve 7 is demagnetized and the press stops at the setting point. At this time, the self-holding state of the relay coil 5 is simultaneously released, and its B contact 25 is made. At this point, the A contact 19 of the rotary cam switch for preventing restart has already been made, so the timer circuit 23 is set at the same time as the B contact 25 is made and starts timing operation, and the speed designation signal SPM is applied. The A contact 20 is made after a correspondingly determined delay time has elapsed. Therefore, when the operator presses the operation button, A contact 1
and 3 are made, the relay coil 13 is demagnetized and the A contact 14 of line 1 is broken until the timer circuit 23 makes the A contact 20, so the relay coil 5 is not energized, and the press device The system is not restarted either. On the other hand, when the delay time determined in response to the speed designation signal SPM has elapsed, the timer circuit 20 closes the A contact 20, energizes the relay coil 13, and closes the A contact 14 of the line 1. Therefore, if the operator presses the operation button at this time and A contacts 1 and 3 are made, relay coil 5
is energized, the A contact 6 is made, the solenoid valve 7 of the clutch brake is energized, and the press is restarted. Furthermore, if the operation button is kept pressed after pressing the operation button for the first intermittent operation, the relay coil 11 remains demagnetized when the press device stops at the set point. . Therefore, the A contact 15 remains broken, and the relay coil 13 remains demagnetized. Therefore, after the set point has stopped, release the run button, energize the relay coil 11, and then press the run button again. The press cannot be restarted unless pressed. In this way, in this embodiment, during intermittent operation,
When the press stops at the set point, the timer circuit 23
is started, and after the timer circuit 23 measures a delay time corresponding to the number of consecutive strokes at that time, restarting becomes possible. As shown in FIG. 3, the allowable number of intermittent strokes is determined in accordance with the number of continuous strokes, so the delay time of the timer circuit 23 is determined by the speed designation signal.
The timer circuit 23 is controlled by the SPM and is controlled so that this delay time satisfies the following (Equation-1).
By configuring this, there is no danger that the number of intermittent strokes will exceed the allowable number of intermittent strokes. T≧T ₁ −T ₂ (Formula-1) However, T: Delay time T ₁ : 60 ÷ Allowable intermittent stroke number T ₂ : 60 ÷ Continuous stroke number In addition, in (Formula-1), if T ₁ − T ₂ is negative (i.e., when the number of continuous strokes in Fig. 3 is P
Needless to say, if the number of points is less than the number of points, the value of T becomes 0. Further, in the above example, the crank angle of the press device is detected by a rotary cam switch, but it may also be detected by an encoder. The essence of the present invention is to include a timer circuit that is activated after the set point has stopped, to link the time limit operation time of this timer circuit to the number of continuous strokes, and to enable restarting after the timer circuit has timed out. Therefore, as long as this condition is satisfied, a configuration other than the above, for example, a digital logic circuit may be adopted.

【effect】

As explained above, according to the present invention, during intermittent operation, even if you press the run button immediately after the set point has stopped, the press device will not operate until the set time of the timer circuit, which is determined in conjunction with the number of continuous strokes, has elapsed. Since restart is not performed, it becomes impossible to perform intermittent operation exceeding the allowable intermittent stroke number.
This makes it possible to prevent many troubles caused by overheating.

[Brief explanation of the drawing]

Fig. 1 is an expanded connection diagram of a press control circuit according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the make/break timing of the rotary cam switch, and Fig. 3 is an illustration of the relationship between the number of continuous strokes and the number of allowable intermittent strokes. Characteristic diagram shown. 1, 3...A contact of the operation button, 2, 4...B contact of the operation button, 5...Relay coil, 7...
Solenoid valve, 13... Relay coil, 14... A contact, 20... On-delay contact, 23... Timer circuit, 24... A contact for safety 1 stroke selection.

Claims (1)

[Scope of Utility Model Registration Claim] In a control circuit for a press device that operates intermittently while stopping at a set point, the output and operation of a timer that is activated when the set point stops and generates an output after a set time elapses. A start signal is given to the press device by logical product with the output of the operation switch on the panel, and a continuous stroke number signal indicating the rotation speed of the press device is input to the timer, and the input continuous stroke number is The time required for one stroke when the press equipment is operated at the speed indicated by the signal is defined as T ₂ ,
When the time required to release the heat that is generated intermittently when the press device is operated intermittently at the speed indicated by the input continuous stroke number signal is defined as T ₁ ,
Based on the input continuous stroke number signal, when the time of _T1 is longer than the time of _T2 , the set time T of the timer is variably set so as to satisfy T≧ _T1 − _T2 . An overheating prevention circuit for a press machine, which is characterized by: