JPS6313897B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a material supply device that can sequentially supply a plurality of materials stored in a stack magazine to a press one by one. In general, this type of material supply device lowers a vacuum cup 1 of a material conveyance device to a predetermined position as shown in FIG. The uppermost blank material 3a is picked up and raised, and this blank material 3a is delivered to a press device (not shown). On the other hand, the lifter 4 raises the blank material 3 in the frame 2 by the thickness t of the blank material 3 every time the blank material is conveyed, so that the uppermost blank material 3a is always at a constant height. . By operating the lifter 4 in this manner, it can be linked to quick press operation. Also, as shown in Figure 2, in the stack magazine 5,
If a plurality of stations are provided as shown in Fig. 1, even if all the blanks 3 at one station have been conveyed, it is possible to move to the next station, allowing continuous blanking without stopping the press operation. Material 3 can be supplied. However, when the lifter 4 raises the blank material 3 by a predetermined thickness t of the blank material 3, the position of the uppermost blank material 3a may become lower than the desired feed level due to variations in the sheet thickness, etc. It becomes high, and as a result, Bakyum Cup 1
The vacuum cup 1 cannot attract (clamp) the blank material 3a, causing misfeed, and the vacuum cup 1 and the blank 3a may interfere with each other, causing damage to the vacuum cup 1. In order to solve the above problems, the conventional material supply device is equipped with a limit switch for setting the feed level on the frame of each station, and the lifter is controlled so that the topmost blank material 3a is always at a constant level. Ta. However, in such conventional material feeding devices, the feed level must be set by the mounting position of the limit switch on the frame. (2) It is difficult to install a limit switch when the stations are close to each other for small blank materials. (3) When the feed level changes due to changes in mold height, etc. There were problems such as the need to set the limit switch again. An object of the present invention is to provide a material supply device that can solve the above problems. According to the present invention, a detector is provided in the vicinity of the vacuum cup of the material conveying means to detect the raised position of the uppermost material among the plurality of materials stored in the stack magazine after the vacuum cup has descended to a predetermined position. The amount of lift by the lifter is controlled based on the output of this detector. The present invention will now be described in detail with reference to the accompanying drawings. FIG. 3 shows the main part of the mechanism of the material supply device according to the present invention, in which a beam 11 protrudes from the bottom of the vacuum cup 10, and an upper limit switch 12 and a lower limit switch 13 are attached to the beam 11.
has been established. The upper limit switch 12 and the lower limit switch 13 operate when the uppermost blank 1 of the blanks 15 housed in the frame 14 of the stack magazine
This is provided to define the upper and lower limits of the raised position of the uppermost blank material 15a, and after the arm 16 is lowered and the vacuum cup 10 is stopped at a predetermined feed level, the raised position of the uppermost blank material 15a is detected. That is, when the upper limit switch 12 is turned on, it is possible to detect an excess of the amount of rise of the blank material 15, and the lower limit switch 1 is turned on.
3 is turned off, it is possible to detect an insufficient amount of rise of the blank material 15. Note that the upper limit switch 12 and the lower limit switch 13 have their respective operating points within a predetermined tolerance (for example, 1 mm).
They are arranged so that they are shifted by the same amount. FIG. 4 is a block diagram showing an embodiment of the rise amount control circuit of the material supply device according to the present invention. Fourth
In the figure, first, the start switch 20 is turned off, the subtraction circuit 21 is made inactive, that is, the signal "1" is not applied to the OR circuit 22 from the subtraction circuit 21, and then the preparation button 23 is pressed. At this time, the vacuum cup 10 (FIG. 3) is stopped at a predetermined feed level, and the blank material 15 is
is not raised by the lifter 17, and the upper limit switch 12 and lower limit switch 1
3 are all off. Since the lower limit switch 13 is off, it outputs a signal "0", and the inverter 24 inverts this signal "0" and outputs it to the AND circuit 25.
The AND circuit 25 is enabled to operate. here,
When the preparation button 23 is pressed, a signal "1" is applied from the preparation button 23 to the motor 27 via the AND circuit 25, the OR circuit 22, and the amplifier 26, and the lifter 17 is raised by the driving force of the motor 27. be done. As the lifter 17 rises, the blank material 15
rises and the uppermost blank 15a reaches the detection position of the lower limit switch 13, the output signal of the lower limit switch 13 becomes "1", the inverter 24 inverts this signal "1" and applies it to the AND circuit 25, The AND circuit 25 is made inoperative. Therefore, the output signal of the OR circuit 22 becomes "0", the rotation of the motor 27, that is, the lifting of the lifter 17 is stopped, and the inverter 28, which inverts the output signal "0" of the OR circuit 22, outputs an inverted signal "0". 1” is output as the positioning completion signal ED. When the above-mentioned positioning completion signal ED is input, the conveyance device picks up the uppermost blank material 15a with the vacuum cup 10, then raises the arm 16, conveys it to the press device (not shown), and receives it in the press device. It works like passing. On the other hand, when the AND circuit 25 becomes inactive and outputs a signal "0", the inverter 29 inputting this signal "0" applies a signal "1" to the load terminal LD of the latch circuit 31 via the OR circuit 30. .
The latch circuit 31 latches the output signals of the upper limit switch 12 and the lower limit switch 13 in response to the rise of the signal "1" applied to the load terminal LD, and applies the latched signals to an AND circuit 32 and a NAND circuit 33, respectively. When both of the two input signals are "1" (when both limit switches 12 and 13 are on), the AND circuit 32 outputs a signal "1" to the subtraction instruction input SU of the addition/subtraction circuit 34, and the NAND circuit 33 outputs the signal "1" to the two input signals When both are "0" (when limit switches 12 and 13 are both off), the addition/subtraction circuit 34
A signal “1” is output to the addition instruction input AD. In this case, since the lifter 17 is stopped after the lower limit switch 13 is turned on, the lower limit switch 13 is turned on and the upper limit switch 12 is turned off, and the AND circuit 32 and NAND circuit 33 are turned on. Both output a signal "0". The adder circuit 34 commands the lifting amount of the lifter 17, and adds plate thickness data t corresponding to the thickness of one sheet of the blank material 15 and correction data α smaller than the plate thickness data t. , AND circuit 3
Based on the outputs of 2 and NAND circuit 33, that is, the states of upper limit switch 12 and lower limit switch 13, the increase amount command values shown in Table 1 are output.

[Table] That is, when both the upper limit switch 12 and the lower limit switch 13 are turned on and a signal "1" is applied from the AND circuit 32 to the subtraction instruction input SU, the data obtained by subtracting the correction data α from the plate thickness data t (t- α) is output as the rising amount command value, the rising limit switch 12 and the lower limit switch 13 are both turned off, and the NAND circuit 3
When the signal "1" is added to the addition instruction input AD from 3, the data (t+α) obtained by adding the plate thickness data t and the correction data α is output as the increase amount command value,
When the signal "1" is not applied to either the addition instruction input AD or the subtraction instruction input SU, the plate thickness data t is output as the increase amount command value. The increase amount command value output from the addition/subtraction circuit 34 is preset to the subtraction circuit 21 at substantially the same timing as the latch timing of the latch circuit 31. In this case, plate thickness data t is preset as the increase amount command value. The start switch 20 is turned on at an appropriate time after the above-mentioned first positioning completion signal ED is input to the conveyance device and the vacuum cup 10 has suctioned and lifted the blank material 15a.When the switch is turned on, the start switch 20 Signal “1” from
is added to the enable terminal EN of the subtraction circuit 21,
The subtraction circuit 21 is made operational. The subtraction circuit 21 is formed of, for example, a down counter, and when it becomes operational, it applies a signal "1" to the motor 27 via the OR circuit 22 and the amplifier 26 to drive the motor 27, unless the count value becomes 0. do. The lifter 17 is raised by the driving force of the motor 27, and the motor 27
A pulse train is applied from the pulse oscillator 35 to the subtraction input DN of the subtraction circuit 21 in accordance with the amount of rotation (the amount of rise of the lifter 17). The subtraction circuit 21 counts pulses added sequentially from the preset increase command value, and when the count value reaches 0, outputs a signal "0". When the output signal of the subtraction circuit 21 becomes "0", the rotation of the motor 27, that is, the lifting of the lifter 17 is stopped, and the inverter 28 outputs an inverted signal "1" as the positioning completion signal ED. By the above operation, the blank material 15 is raised by the thickness thereof, and the uppermost blank material 15a is placed in a standby state at the feed level. After the conveyance device transfers the blank material 15 to the press device, the arm 16 is lowered and stopped at a predetermined feed level, and the conveyance device outputs the conveyance device home position signal IN (“1”) and transfers the uppermost blank material 15a. adsorbs and begins to rise. said signal
IN is applied to the load terminal LD of the latch circuit 31 via the OR circuit 30, and the latch circuit 31 switches the upper limit switch 12 and the lower limit switch 13 in response to the fall of the signal IN, as described above.
Latch the output signal. The addition/subtraction circuit 34 then switches the limit switch 1
Based on the outputs of 2 and 13, a command value corresponding to the amount to be increased next is output. That is, when the position of the uppermost blank material 15a deviates from a predetermined feed level by a predetermined amount due to an accumulated error in the thickness of the blank material 15, etc., the material thickness data t is corrected by the correction data α (the correction data (addition or subtraction)) and output this as a command value corresponding to the amount of increase to be performed next. Thereby, the amount of rise of the blank material 15 can be controlled so that the uppermost blank material 15a can stand by at a substantially constant height. In this embodiment, the upper limit switch 12 and the upper limit switch 13 are used as the position detector for the uppermost blank material, but the present invention is not limited to this. For example, as shown in FIG. 5, one displacement sensor 36 may be used. Good too. By using this displacement sensor 36, the mounting part becomes simple, and
The circuit section (FIG. 6) of the displacement sensor 36 allows the upper and lower limits of the ascending position of the uppermost blank material 15a to be easily changed. That is, the displacement sensor 36
A voltage signal corresponding to the position of 6a is applied to the A inputs of comparators 37 and 38, respectively. Comparator 3
A voltage signal corresponding to a predetermined upper limit position is applied to the B input of the comparator 38 from the upper limit setting volume 39, and a voltage signal corresponding to the desired lower limit position is applied from the lower limit setting volume 40 to the B input of the comparator 38. has been added. Since the comparators 37 and 38 each output a signal "1" when the A input becomes larger than the B input, the comparator 37 outputs the signal "1" when the uppermost blank material 15a is above the preset upper limit position. ", and the comparator 38 outputs a signal "1" when the uppermost blank material 15a is above a preset lower limit position. That is, the output signals of the comparators 37 and 38 are transferred to the above-mentioned upper limit switch 12, lower limit switch 12 and lower limit switch 1, respectively.
It can be used as a signal equivalent to the output signal of No. 3. As explained above, according to the present invention, since the position detector is provided on the conveying device side, there is no need for a limit switch for each station that accommodates a blank material, which is a problem with the conventional method, and the number of limit switches is drastically reduced. Further, since the feed level is set on the conveying device side (at the lowered position of the vacuum cup), it is extremely easy to change the feed level in accordance with changes in the height of the mold, etc.

[Brief explanation of the drawing]

FIG. 1 is a mechanical diagram of a main part of a material supply device, FIG. 2 is a perspective view showing an example of a stack magazine, and FIG. 3 is a mechanical diagram of a main part of an embodiment of a material supply device according to the present invention. FIG. 4 is a block diagram showing one embodiment of the rise amount control circuit of the material supply device according to the present invention, and FIG.
The figure is a main part mechanical diagram showing another embodiment of the material supply device according to the present invention, and FIG. 6 is a circuit section of a displacement sensor. 10... Bakyum Cup, 11... Liang, 12
...Upper limit switch, 13...Lower limit switch, 14...Frame, 15...Blank material, 16...Arm, 17...Lifter, 20...
Start switch, 21...Subtraction circuit, 23...
Preparation button, 27...Motor, 34...Addition/subtraction circuit, 36...Displacement sensor.

Claims (1)

[Claims] 1. A material conveying means that lowers the vacuum cup to a predetermined position, adsorbs the best material among the plurality of materials stored in the stack magazine, and conveys the material to the press device; In a material supply device having a lifter that raises the material in the stack magazine by the thickness of the material based on the thickness data of the material each time the material is transported,
a detector disposed near the vacuum cup of the material conveying means so as to be movable up and down together with the vacuum cup, and detecting the relative position of the uppermost material in the stack magazine with respect to the vacuum cup after the vacuum cup has been lowered to a predetermined position;
Based on the output of the detector, when the position of the top material is above the upper limit position, data smaller than the plate thickness data by a predetermined value is output to the lifter as plate thickness data, and the position of the top material is set to the lower limit position. A material supply device comprising: a rise amount control means for outputting data larger than the plate thickness data by a predetermined value to the lifter as plate thickness data when: