JP4127733B2 - Safety equipment for press machines - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press machine, and more particularly to a safety device for a press machine.
[0002]
[Prior art]
In industrial machines, like a press machine, when a worker's body is in a dangerous position, a light-type safety device that stops driving of the press machine is attached. For example, FIG. 6 is a diagram for explaining an example of such a light safety device. As shown in the figure, the beam-type safety device is provided between the press machine and the worker, and is composed of a light emitting unit 1, a light receiving unit 2, and a control unit 3. Then, according to the control signal output from the control unit 3, the light emitting unit 1 emits light 1-2, 1-3,..., 1-n sequentially from, for example, the uppermost light emitting element 1-1, and the light receiving unit 2 The corresponding light is received by the light receiving elements 2-1, 2-2, 2-3,.
[0003]
And if the light from one of the light-emitting elements cannot be received by the corresponding light-receiving element, it is assumed that a part of the worker's body, parts or materials are in a dangerous position for the operation of the press machine. Even if the machine drive signal is input, the drive of the press machine, that is, the lowering operation of the press machine (slide) is stopped. Further, when light emission from the light emitting element is interrupted during operation of the press machine, the drive of the press machine is immediately stopped.
[0004]
On the other hand, the press machine is provided with a plurality of rotary cam switches in addition to the above-described beam-type safety device, and is used for slide top dead center stop control and adjustment of overrun and overload. In addition, for example, the timing until the slide reaches the bottom dead center from the top dead center is detected, and during this time, the above-mentioned light safety device is operated, and the timing until the slide reaches the top dead center from the bottom dead center is detected. It is also used for the control to invalidate the function of the light beam safety device.
[0005]
[Problems to be solved by the invention]
However, in the safety device for the press machine, the rotary cam switch is connected to the shaft of the press machine via a chain. For this reason, for example, when trouble such as chain breakage occurs, the function of the rotary cam switch is lost.
[0006]
In order to solve the above-described problems, the present invention provides a safety device for a press machine that immediately detects the trouble and stops the drive of the press machine when a trouble such as chain breakage occurs.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a safety device for a press machine having a slide that is driven up and down, and a position detecting means for detecting the position of the slide connected via a chain. According to the output of the detection means, a discriminating means for discriminating whether the slide is descending or rising, a measuring means for measuring the slide descending time (Td) and the ascending time (Tu), and the descending time ( T d ) is a time obtained by multiplying the actual descending time of the slide by a certain constant exceeding 1, and when the relationship between the descending time (Td) and the ascending time (Tu) is (Td)> (Tu) This can be achieved by providing a safety device for a press machine that determines that the chain has no disconnection abnormality and has a determination means for determining that the chain is abnormally broken when (Td) ≦ (Tu). .
[0008]
Here, the position detection means is, for example, a rotary cam and a switch, and the rotation of the rotary cam is obtained by rotating the shaft of the press machine via a chain. The rotary cam switch is, for example, a limit switch, and is turned on / off according to the unevenness formed in the corresponding rotary cam.
[0009]
The discriminating means discriminates whether the slide is descending or rising, and specifically discriminates according to the on / off signals of the two rotary cam switches constituting the position detecting means.
[0010]
The measuring means measures the slide descent time (Td) from the corresponding rotary cam switch on / off signal, and further measures the slide rise time (Tu).
[0011]
Further, the judging means compares the falling time (Td) and the rising time (Tu) obtained as a result of the measurement by the measuring means, and when (Td)> (Tu), there is no problem such as chain breakage. It is determined that the rotary cam switch is operating normally. On the other hand, when (Td) <(Tu), troubles such as chain breakage occur and it is determined that the press machine is abnormal.
[0012]
By configuring in this way, it is possible to detect abnormalities in the press machine, and in particular, it is possible to accurately detect abnormalities such as chain breaks and stop the press machine.
[0013]
According to claim 2 is the invention described in claim 1, wherein the chain in the fall time (Td) abnormalities detected by previous SL safety device is configured to prevent the occurrence of abnormality.
[0014]
The claim 1 detects an abnormality when the slide rises from the bottom dead center to the top dead center. However, the claim 2 according to the present example relates to the slide descending from the top dead center to the bottom dead center. Is detected by the light beam safety device.
[0015]
Therefore, by configuring in this manner, even if a trouble such as chain breakage occurs while the slide is descending, the above-described light safety device works to protect the worker's body and prevent disasters. .
[0017]
With this configuration, the measured value of the fall time (Td) is increased, and when the rise time (Tu) is longer than the fall time (Td), it is determined that a trouble such as a chain break has occurred. You can know the occurrence of trouble.
[0018]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the position detecting means includes a rotary cam and a switch.
[0019]
This example specifies the configuration of the position detecting means.
[0020]
According to a fourth aspect of the present invention, in the third aspect of the present invention, the rotary cam is composed of two or more cams.
[0021]
Here, for example, when two rotary cams are configured, each cam is divided into 180 °, for example, and when four rotary cams are used, for example, each cam is divided into 90 ° and used.
[0022]
By configuring in this way, more detailed rotary cam angle setting is possible.
[0023]
According to the fifth aspect of the present invention, there is provided the position detecting means for detecting the position of the slide connected via the chain, and the slide is lowered or raised by the output of the position detecting means. A determination means for determining the inside of the slide; and a measurement storage means for measuring and storing a first fall time (Td1) of the slide, which is a time obtained by multiplying the actual fall time of the slide by a certain constant exceeding 1. Measuring means for measuring the second fall time (Td2) of the slide and the rise time (Tu) of the slide; the first fall time (Td1) and the second fall time (Td2); When (Td1)> (Td2), it is determined that there is no disconnection abnormality in the chain. When (Td1) ≦ (Td2), it is determined that the chain is abnormally disconnected, and (Td1)> ( When Tu), it is determined that the chain is not broken In addition, this can be achieved by providing a safety device for a press machine having a judging means for judging that the chain is abnormally cut when (Td1) ≦ (Tu).
[0024]
Here, the position detecting means and the discriminating means are the same as in the configuration of the first aspect, and the measuring means is a first descent time (Td1) of the slide and a second descent time (Td2) of the slide. And the rise time (Tu) are measured, and the measurement result of the first fall time (Td1) of the slide is stored in a storage means such as a ROM or RAM.
[0025]
The judging means compares the first fall time (Td1) and the second fall time (Td2) obtained as a result of the measurement by the measuring means, and when (Td1) <(Td2), the fall is abnormal. It is judged that. Further, the first fall time (Td1) and the rise time (Tu) are compared, and when (Td1) <(Tu), it is determined that the rise is abnormal.
[0026]
By configuring in this way, it is possible to detect an abnormality of the press machine in both cases of rising and lowering, and in particular, it is possible to accurately detect abnormality such as chain breakage.
[0027]
According to a sixth aspect of the present invention, in the invention of the fifth aspect , the falling time (Td1) is a time obtained by multiplying an actual falling time of the slide by a constant constant larger than one.
[0028]
According to a seventh aspect of the present invention, in the invention of the fifth aspect , the position detecting means comprises a rotary cam and a switch.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
<First embodiment>
FIG. 1 is a schematic diagram of a safety device for a press machine according to an embodiment of the present invention, including a configuration of the press machine. The press machine 5 has a bed 7 to which a slide 6 that moves up and down is attached, and a lower mold (not shown) is attached to the lower part thereof. Moreover, a material is put between the above-mentioned slide 6 and the bed 7, and a press work is performed.
[0032]
A light safety device (not shown) is installed in front of the press machine 5. This light-type safety device is composed of a light emitting part and a light receiving part as described above, and light is emitted sequentially from each light emitting element provided in the light emitting part in accordance with a control signal from the control circuit, and light is received by the facing light receiving element. It is a configuration. Therefore, the number of light receiving elements is also made up of a number corresponding to the light emitting elements, and only the light from the facing light emitting elements is received.
[0033]
On the other hand, the press main shaft 8 that moves the slide 6 up and down is driven up and down by an eccentric shaft 9 having an eccentric rotation shaft. That is, the eccentric shaft 9 is rotationally driven by a motor (not shown), the rotational driving is converted into the vertical driving by the eccentric rotating shaft of the eccentric shaft 9, and the press main shaft 8 is driven. A chain 10 is wound around the eccentric shaft 9, and the other end of the chain 10 is wound around a rotary shaft 11 ′ of the rotary cam 11. The rotary cam 11, the rotary cam rotating shaft 11 ′, and the switch are provided in the rotary cam box 12.
[0034]
FIG. 2 is a schematic side view showing the configuration of the rotary cam 11 and limit switch 13 in the rotary cam box 12. In the figure, a plurality of rotary cams 11-1, 11-2, 11-3,... Are attached to a rotary shaft 11 ′ of the rotary cam 11, and limit switches 13-1, 13-2,. 13-3 are arranged. Here, for example, it is assumed that the limit switch 13-1 is a rotary cam that sets the timing of the descent time while the slide 6 moves from the top dead center to the bottom dead center. Further, it is assumed that the limit switch 13-2 is a rotary cam that sets the timing of the rising time for moving the slide 6 from the bottom dead center toward the top dead center. The other rotary cams 11-3 and the like are cams used for adjusting overload, overrun, and the like.
[0035]
Therefore, in the above configuration, the timing of the slide 6 fall time can be set by the output signal of the limit switch 13-1, and the timing of the slide 6 rise period can be set by the output signal of the limit switch 13-2. Can do.
[0036]
FIG. 3 shows a CPU 14 to which output signals such as the above-described limit switches 13-1 and 13-2 are supplied. The CPU 14 performs an abnormality detection process according to the limit switches 13-1 and 13-2 and the clutch-on signal. . The clutch-on signal is output by an operation of a press start button performed by an operator.
[0037]
The abnormality detection operation of the safety device for a press machine having the above configuration will be described below.
[0038]
FIG. 4 is a diagram showing a relationship of output signals from the limit switches 13-1 and 13-2 with respect to the position of the press machine (the position of the slide 6). FIG. 5 is a flowchart for explaining the processing operation of this example.
[0039]
First, it is assumed that the initial press machine (slide 6) stops at a position where the rotation angle is 0 degree. It should be noted that the press machine (slide 6) may actually be located in the range from the top dead center (rotation angle is 0 degree) to minus (-) 30 degrees in FIG.
[0040]
In this initial state, when the operator presses the press start button, a clutch (not shown) is driven, the rotational force of the motor is transmitted to the eccentric shaft 9, and the eccentric shaft 9 rotates to move the press main shaft 8 downward. To move the slide 6 downward. Also, the clutch-on signal shown in FIG. 3 is supplied to the CPU 14 (step (hereinafter referred to as S) 1) is YES).
[0041]
On the other hand, rotation of the eccentric shaft 9 causes the rotation shaft 11 'of the rotary cam 11 to start rotating via the chain 10. First, the rotation of the rotary cam 11-1 turns on the limit switch 13-1, and this ON signal is supplied to the CPU 14. (S2 is YES). As shown in FIG. 4, this supply time is a period from the top dead center to the bottom dead center, and is a descent time of the slide 6. The CPU 14 measures the time from when the above-mentioned clutch-on signal is supplied and when the on-signal is not supplied after the on-signal is supplied from the limit switch 13-1 (S3, S4 is NO, S3). This measurement time is set to (Td) (S5). In this calculation, the CPU 14 multiplies one or more constants (for example, a constant 1.2) to obtain the fall time (Td).
[0042]
Next, when the eccentric shaft 9 continues to rotate by the rotational force of the motor and the slide 6 exceeds the bottom dead center, the limit switch 13-1 outputs an off signal, and an on signal is supplied from the limit switch 13-2 instead. (S6 is YES). This ON signal is output while the slide 6 reaches 330 degrees from the bottom dead center, and the CPU 14 measures the rising time (S7). When the supply of the ON signal from the limit switch 13-2 stops, the CPU 14 sets this measurement time as the rising time (Tu) (S7, S8 is NO, S7, S8 is YES, S9).
[0043]
Next, the CPU 14 compares the measured descent time (Td) and rise time (Tu) while the press main shaft 8 (slide 6) is stopped near the top dead center (S10). As described above, when the fall time (Td) is measured, for example, a constant of 1.2 is multiplied by the actual fall time, and the rise time is 330 degrees from the bottom dead center as shown in FIG. (Td)> (Tu) if there is no abnormality in the chain 10 or the like. That is, the CPU 14 determines that the measured value is normal when the measured value is in the above relationship (NO in S10).
[0044]
On the other hand, when the above measurement result is in the relationship of (Td) <(Tu), for example, the rising time is abnormally long, and the CPU 14 outputs an abnormal signal assuming that an abnormality such as the chain 10 is broken (S10). YES, S11).
[0045]
Therefore, it can be immediately understood that an abnormality has occurred in the drive mechanism of the rotary cam switch such as the cutting of the chain 10 by processing as in this example. In such a case, the drive of the press machine can be stopped and the safety of the press machine can be ensured.
[0046]
In the description of the above-described embodiment, an abnormality such as the cutting of the chain 10 is detected when the press machine (slide 6) is raised. However, when the press machine (slide 6) is lowered, the light beam type described above is used. Safety device works.
[0047]
Further, in the description of the above embodiment, in the measurement of the fall time, a constant exceeding 1 (for example, 1.2) is multiplied. However, other numerical values may be used, and the actually measured value is not multiplied by the constant. It may be the falling time (Tu).
<Second Embodiment> Next, a second embodiment of the present invention will be described.
[0048]
This example will also be described using the schematic diagram of the safety device of the press machine shown in FIG. Further, as shown in FIG. 2, the configurations of the rotary cam 11 and the limit switch 13 in the rotary cam box 12 are the same as those in the above-described embodiment.
[0049]
In this example, the first descent time is stored in the memory in advance, and the descent time measured after the second time is compared to detect an abnormality when the slide 6 descends. This will be specifically described below.
[0050]
First, it is assumed that the initial press machine (slide 6) is stopped at a position where the rotation angle is 0 degrees as described above. It should be noted that the press machine (slide 6) may actually be located in the range from the top dead center (rotation angle is 0 degree) to minus (-) 30 degrees in FIG.
[0051]
In this initial state, when the operator presses the press start button, a clutch (not shown) is driven, the rotational force of the motor is transmitted to the eccentric shaft 9, and the eccentric shaft 9 rotates to move the press main shaft 8 downward. To move the slide 6 downward. Further, a clutch-on signal shown in FIG.
[0052]
On the other hand, rotation of the eccentric shaft 9 causes the rotation shaft 11 'of the rotary cam 11 to start rotating via the chain 10. First, the rotation of the rotary cam 11-1 turns on the limit switch 13-1, and this ON signal is supplied to the CPU 14. Is done. As shown in FIG. 4, this supply time is a period from the top dead center to the bottom dead center, and is a descent time of the slide 6. The CPU 14 measures the time from when the above-mentioned clutch-on signal is supplied and when the on-signal is no longer supplied after the on-signal is supplied from the limit switch 13-1. This measurement time is defined as (Td1). In this calculation, the CPU 14 multiplies one or more constants (for example, a constant 1.2) to obtain the fall time (Td1).
[0053]
Next, the measurement result (Td1) of the first fall time is stored in a memory (not shown).
[0054]
Next, when the eccentric shaft 9 continues to rotate and the slide 6 exceeds the bottom dead center, the limit switch 13-1 outputs an off signal, and an on signal is supplied from the limit switch 13-2 instead. This ON signal is output while the slide 6 reaches 330 degrees from the bottom dead center, and the CPU 14 measures the rising time.
[0055]
When the supply of the ON signal from the limit switch 13-2 stops, the CPU 14 sets this measurement time as the rising time (Tu).
[0056]
Next, the CPU 14 measures the second fall time (Td2). In this measurement, as described above, the CPU 14 is supplied with the above-described clutch-on signal, and when the on-signal is supplied from the limit switch 13-1, the measurement is started and the time until the on-signal is not supplied is measured. . This measurement time is defined as (Td2). In this calculation, the above-mentioned constant 1.2 is not multiplied.
[0057]
Next, the CPU 14 reads the first fall time measurement result (Td1) stored in the memory and compares it with the fall time measurement result (Td2) measured this time. When (Td1) <(Td2), it is determined that there is an abnormality. That is, the fact that the currently measured descent time (Td2) is longer than the descent time (Td1) stored in the memory means that the descent time has become longer during this descent operation, such as the chain 10 being cut. Judge that an abnormality has occurred.
[0058]
Therefore, in such a case, it is assumed that an abnormality has occurred in the press machine, and the subsequent press operation is stopped.
[0059]
On the other hand, when there is no problem in the measurement result of the second fall time (Td2), the measurement of the third fall time (Td3), the measurement of the fourth fall time (Td4), and so on are repeated. In each case, determine whether there is any abnormality.
[0060]
Similarly to the first embodiment described above, the comparison processing of the ascending time (Tu) and the descending time (Td1) of the slide 6 is performed in the same manner. For example, when (Td1) <(Tu), the ascent is abnormal. It is judged that.
[0061]
Therefore, according to this example, whether the press machine (slide 6) is moving up or down, it is possible to immediately detect an abnormality such as the breaking of the chain 10, and to ensure the safety of the pressing machine.
[0062]
In the description of the above-described embodiment example, when the first falling time (Td1) is set, a constant exceeding 1 (for example, 1.2) is multiplied, but other values may be used.
[0063]
【The invention's effect】
As described above in detail, according to the present invention, troubles such as chain breakage can be immediately detected, and the drive of the press machine can be stopped.
[0064]
Further, it is possible to detect an abnormality of the press machine, particularly when the press machine is raised or lowered, and to detect an abnormality such as a broken chain in particular.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a safety device for a press machine according to an embodiment of the present invention, including a configuration of the press machine.
FIG. 2 is a schematic side view showing a configuration of a rotary cam and a limit switch in a rotary cam box.
FIG. 3 is a diagram illustrating a CPU to which an output signal such as a limit switch is supplied.
FIG. 4 is a diagram showing a relationship of an output signal from a limit switch with respect to the position of the press machine (slide position).
FIG. 5 is a flowchart illustrating processing of the present exemplary embodiment.
FIG. 6 is a diagram illustrating the configuration of a light beam safety device.
[Explanation of symbols]
5 Press machine 6 Slide 7 Bed 8 Press main shaft 9 Exen shaft 10 Chain 11, 11-1, 11-2, 11-3 Rotary cam 11 'Rotating shaft 12 Rotary cam box 13, 13-1, 13-2, 13- 3 Limit switch

Claims (7)

In a safety device of a press machine having a slide that drives up and down, and a position detection means that detects the position of the slide is connected via a chain,
A discriminating means for discriminating whether the slide is descending or rising by the output of the position detecting means;
Measuring means for measuring the descent time (Td) and the ascending time (Tu) of the slide;
The fall time (T d ) is a time obtained by multiplying the actual fall time of the slide by a constant larger than 1, and the relationship between the fall time (Td) and the rise time (T u ) is expressed as (T d )> ( A judgment means for judging that there is no disconnection abnormality in the chain when (Tu), and a determination that the chain is abnormal when (Td) ≦ (Tu);
A safety device for a press machine, comprising: 2. The safety device for a press machine according to claim 1, wherein the safety device detects a break of the chain during the descent time (Td) and prevents the occurrence of an abnormality. The safety device for a press machine according to claim 1 or 2, wherein the position detecting means is composed of a rotary cam and a switch. 4. The safety device for a press machine according to claim 3 , wherein the rotary cam is composed of two or more cams. Determining means for detecting a position of a slide connected via a chain, and determining whether the slide is descending or rising by an output of the position detecting means;
Measurement storage means for measuring and storing the first descent time (Td1) of the slide, which is a time obtained by multiplying the actual descent time of the slide by a certain constant exceeding 1.
Measuring means for measuring the second fall time (Td2) of the slide and the rise time (Tu) of the slide;
When the relationship between the first falling time (Td1) and the second falling time (Td2) is (Td1)> (Td2), it is determined that there is no disconnection abnormality in the chain, and (Td1) ≦ (Td2) the chain is determined to be abnormal disconnection when, (Td1)> determined not to abnormality of cutting the chain when the (Tu), which is the chain abnormal disconnection when (Td1) ≦ (Tu) Judging means for judging,
A safety device for a press machine, comprising: 6. The safety device for a press machine according to claim 5 , wherein the position detecting means is composed of a rotary cam and a switch. The safety device for a press machine according to claim 6 , wherein the rotary cam is composed of two or more cams.

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