JP2010194567A - Mechanism for and method of holding workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism for and a method of holding a workpiece, by which production of double blanks is suppressed and productivity is stabilized. <P>SOLUTION: This mechanism 100 for holding the workpiece W from a stack 20 in which a plurality of the workpieces W are stacked includes: the stack 20; guides 21 which are arranged side by side with the stack 20 and with which the workpiece W is positioned; magnetic floaters 21 with which magnetic force is imparted to the stack; an air cylinder 10 with which the uppermost workpiece of the stack 20 is sucked and held; and an air blow 22 with which air is run into a space between the uppermost workpiece W and a workpiece W1 under the workpiece W when the uppermost workpiece W is lifted in an accelerated manner by the air cylinder 10 and stopped suddenly in a region surrounded with guides 21. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a workpiece holding mechanism and a workpiece holding method.

In the field of press working, a workpiece is generally handled in a state of a stacked stack. Then, the workpieces are conveyed one by one from the stack to a press machine and subjected to press work.
An air cylinder is used as a method for conveying the workpiece. Specifically, the suction means provided on the piston of the air cylinder sucks and holds the top work of the stack, moves the work up and down one by one, and then sucks and conveys the work on a belt conveyor or the like. .

However, when raising the uppermost workpiece in the stack, the negative pressure is generated between the workpiece and the lower workpiece. The phenomenon is called “double blank”.)
If it does so, while the workpiece | work is conveyed, the lower workpiece | work which stuck will fall suddenly, or two workpiece | work will be supplied to a press machine at once. The former leads to personal injury, and the latter may cause the mold to be damaged when a large force is applied to the mold when it is pressed.

  In order to prevent such a double blank, a method of detecting the presence or absence of the occurrence of a double blank from the weight of the blank placed on the idle stage is disclosed (for example, see Patent Document 1).

JP 2008-56384 A

  However, in the detection method described in Patent Document 1 described above, although the double blank can be suppressed from being pressed, the double blank is detected during the conveyance of the workpiece, so that the workpiece conveyance is not efficient. For this reason, when a double blank occurs frequently, subsequent conveyance of a workpiece | work is not fully performed but productivity will fall.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a work holding mechanism and a work holding method that suppress the generation of a double blank before conveyance and stabilize the productivity.

  The present inventor has intensively studied to solve the above problems, and when the air cylinder holds and holds the work and raises the work, the acceleration of the work is suddenly stopped on the way, thereby lowering the lower side of the double blank. I thought about how to shake off the work. And it discovered that the said subject could be solved by shaking off a workpiece | work under a predetermined mechanism, and came to complete this invention.

  That is, the present invention provides (1) a workpiece holding mechanism for holding a workpiece from a stack in which a plurality of workpieces are stacked, the stack, a guide arranged in parallel to the stack, and positioning the workpiece, the stack The magnet floater that applies magnetic force to the air cylinder, the air cylinder that holds and moves the uppermost workpiece of the stack, and the air cylinder accelerates and raises the uppermost workpiece and suddenly stops in the area surrounded by the guide The workpiece holding mechanism includes an air blow for flowing air between the uppermost workpiece and the workpiece below the workpiece.

  The present invention resides in (2) the workpiece holding mechanism according to (1), wherein the stack is placed on a lifter.

  In the present invention, (3) a plurality of air blows are provided, and the air blown from each air blow collides between the uppermost work and the work below the work (1) or ( The workpiece holding mechanism described in 2) exists.

  The present invention resides in (4) the work holding mechanism according to any one of (1) to (3), wherein the magnet floater also serves as a guide.

  In the present invention, (5) an air cylinder includes a cylinder, a piston head inscribed in the cylinder, and a piston rod that is suspended from the piston head and connected to extend outside the cylinder; A pressure adjusting means for adjusting the pressure of the suction means attached to the lower end, the upper space defined by the cylinder and the piston head, and the lower space defined by the cylinder and the piston head; The workpiece holding mechanism according to any one of the above (1) to (4), wherein the piston is moved up and down and the suction means holds the workpiece.

  The present invention includes (6) an upper air inflow / outflow pipe connected to the cylinder so as to communicate with the upper space and an air flow into and out of the upper space, and a cylinder connected to the cylinder so as to communicate with the lower space. A lower air inflow / outflow pipe, a switching valve for switching air inflow / outflow to / from the upper air inflow / outflow pipe, an air inflow pipe and an open pipe connected to the switching valve, and the air The workpiece holding mechanism according to the above (5), further comprising a compressor connected to the inflow pipe.

  The present invention is (7) a work holding method using the work holding mechanism described in (5) above, wherein the atmospheric pressure in the lower space is made atmospheric pressure, and the atmospheric pressure in the upper space is made larger than atmospheric pressure for a predetermined time. A descent start step for starting the descent of the piston and lowering the piston with the atmospheric pressure in the upper space and the lower space at atmospheric pressure after a predetermined time, a descent contact step for abutting the adsorbing means on the workpiece, A suction step for attracting and holding a workpiece on the means, an upward start step for accelerating and raising the piston by setting the atmospheric pressure in the upper space to atmospheric pressure and the atmospheric pressure in the lower space greater than atmospheric pressure, A step of stopping the piston suddenly by making the air pressure in the upper space the same as that in the lower space, and then setting the air pressure in the upper space to atmospheric pressure, By the air pressure greater than atmospheric pressure, and re-increase step of increasing the piston resides in the workpiece holding method comprising.

  The present invention is (8) a work holding method using the work holding mechanism described in (6) above, wherein a lower air inflow / outflow pipe is connected to an open pipe by a switching valve so that an atmospheric pressure in a lower space is an atmospheric pressure, and an upper air A descent start step for starting the descent of the piston by connecting the inflow / outflow pipe to the air inflow pipe by a switching valve and allowing the air from the compressor to flow in, thereby increasing the atmospheric pressure in the upper space from the atmospheric pressure for a predetermined time, After a lapse of time, the upper air inflow / outflow pipe and the lower air inflow / outflow pipe are connected to the open pipe by the switching valve, and the piston is lowered with the atmospheric pressure in the upper space and the lower space being atmospheric pressure, and the lowering operation is performed so that the work is brought into contact with the suction means A contact step, an adsorption step for adsorbing and holding the work on the adsorption means, and an upper air inflow / outflow pipe connected to the open pipe by a switching valve to The step of starting to raise the piston by accelerating the piston by making the air pressure in the lower space larger than the atmospheric pressure by connecting the lower air inflow / outflow pipe to the air inflow pipe by the switching valve and inflowing air from the compressor With the workpiece positioned on the guide, the upper air inflow / outflow pipe is connected to the air inflow pipe by the switching valve, and the air is made to flow from the compressor so that the air pressure in the upper space is the same as the lower space, There is a work holding method including a stop step for suddenly stopping the piston, and a re-raising step for raising the piston by connecting the upper air inflow / outflow pipe to the open pipe by a switching valve and setting the atmospheric pressure in the upper space to atmospheric pressure.

  The present invention is as described in (7) or (8) above, wherein (9) the descent start step, the descent contact step, the suction step, the rise start step, the stop step, and the re-rise step are all controlled by a timer. It exists in the work holding method.

  In the present invention, (10) the lower limit position of the suction holding means when the piston descends is set to the position of the uppermost workpiece in a state where no gap is formed between the workpieces of the stack ( It exists in the workpiece | work holding method as described in 7) or (8).

  In addition, as long as the objective of this invention is met, the structure which combined said (1)-(10) suitably is also employable.

In the work holding mechanism of the present invention, the air cylinder is suddenly stopped in a region surrounded by a guide on the way to accelerate and raise the uppermost work. At this time, a magnetic force is applied to the stack so that the stacked workpieces repel each other, and air is poured between the uppermost workpiece and the workpiece below the workpiece.
In the work holding mechanism, the sudden lowering causes the lower work to collide with the uppermost work when double blanking occurs, and the reaction causes a downward force. At the same time, the repulsion between the works due to the magnetic force and the repulsion between the works due to the air work, so that the lower work is surely shaken off.

  Further, since the lower workpiece falls in an area positioned by the guide, it is guided by the guard when dropped. For this reason, the lower workpiece is again placed on the stack without shifting.

  Therefore, according to the workpiece holding mechanism of the present invention, it is possible to suppress the occurrence of double blanks before conveyance by a simple method. For this reason, productivity can be stabilized.

  In the work holding mechanism of the present invention, when the stack is placed on the lifter, the lifter can feed the stack upward, so when the air cylinder repeatedly holds and holds the work, the work is picked up at the same position. It can be held.

In the work holding mechanism of the present invention, a plurality of air blows are provided, and when the air blown from each air blow is caused to collide between the uppermost work and the work below the work, Since the collided air escapes in the vertical direction, the air pressure acts in a direction to separate the uppermost workpiece from the workpiece below the workpiece.
For this reason, it becomes possible to suppress a double blank more reliably.

  In the work holding mechanism of the present invention, if the magnet floater also serves as a guide, the entire apparatus can be made more compact.

  In the workpiece holding mechanism of the present invention, it is possible to control the up / down movement and sudden stop of the air cylinder by adjusting the pressure in the upper space and the lower space of the air cylinder. In addition, for the inflow and outflow of air into the upper space and the lower space, if an upper air inflow / outflow pipe and a lower air inflow / outflow pipe are provided and the air inflow / outflow to these can be switched by a switching valve, the piston can be easily connected. It is possible to move up and down and stop suddenly.

  Since the workpiece holding method of the present invention uses the workpiece holding mechanism described above, it is possible to suppress the occurrence of double blanks before conveyance by a simple method. For this reason, productivity can be stabilized.

  In the work holding method of the present invention, when the lowering start step, the lowering contact step, the suction step, the rising start step, the stop step and the re-raising step are all controlled by a timer, the piston can be easily moved up and down. Can be controlled.

  In the work holding method of the present invention, the lower limit position of the suction holding means when the piston descends is set to the position of the uppermost work in a state where no gap is formed between the work pieces of the stack. In this case, the suction holding means reliably sucks and holds the workpiece, and the force for pressing the workpiece is minimized, so that the gap between the workpieces is not completely closed, and as a result, the occurrence of double blanks is further suppressed. Can do.

FIG. 1 is a front view schematically showing a workpiece holding mechanism according to the present embodiment. FIG. 2 is a graph showing the relationship between the position of the suction means in the height direction and time in the work holding method according to the present embodiment. FIG. 3A is a schematic diagram showing the state of the lowering contact step in the work holding method according to the present embodiment, and FIG. 3B shows the state of the stop step in the work holding method according to the present embodiment. It is a schematic diagram, and (c) is a schematic diagram showing a state of a re-raising step in the work holding method according to the present embodiment. FIG. 4 is a schematic view showing pressure adjusting means of the work holding mechanism according to the present embodiment. FIG. 5 is a front view schematically showing a workpiece holding mechanism according to another embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[First Embodiment]
FIG. 1 is a front view schematically showing a workpiece holding mechanism according to the present embodiment.
As shown in FIG. 1, the work holding mechanism 100 includes a lifter 23, a stack 20 placed on the lifter 23, a guide 21 that is arranged in parallel with the stack 20 and positions the work W, and a stack. A magnetic float 21 for applying a magnetic force to 20, an air cylinder 10 for attracting and holding the uppermost workpiece (hereinafter referred to as “the uppermost workpiece”) W of the stack 20, and an air cylinder 10 for moving the uppermost workpiece W Is accelerated and lifted suddenly in the area surrounded by the magnet floater 21, the air between the uppermost workpiece W and the lower workpiece (hereinafter referred to as “lower workpiece”) W <b> 1. And an air blow 22 for pouring.

As the lifter 23, a known one is appropriately used. The lifter 23 may be any of electric type, hydraulic type, and pneumatic type.
The lifter 23 can pitch the stack upward. That is, when the air cylinder 10 repeatedly conveys the uppermost workpiece W and the workpieces are reduced, the lifter 23 pitches the stack 20 upward when the position of the uppermost workpiece W of the stack 20 moves downward. Thus, the air cylinder 10 can suck and hold the uppermost workpiece W at the same position as the position where the uppermost workpiece W is sucked and held first.
If it does so, it will become possible to convey a workpiece | work at a fixed timing, and productivity will improve.

The magnet floater 21 includes an electromagnet on the stack side, and has a function of applying a magnetic force to the stack 20 by being close to the stack. A permanent magnet may be used instead of the electromagnet.
In the work holding mechanism 100, the magnet floater 21 is brought close to the stack 20, whereby the same magnetic force is applied to each work of the stack 20. If it does so, since the workpiece | work W currently laminated | stacked will repel, a double blank becomes difficult to occur.
In particular, when the air cylinder 10 to be described later sucks and holds the uppermost workpiece W and accelerates and raises it, then suddenly stops and swings down the lower workpiece W1, so that the uppermost workpiece W and the lower workpiece W1 have the same polarity. When the magnetic force is applied, the lower workpiece W1 can be effectively shaken off.

In the workpiece holding mechanism 100, the magnet floater 21 also serves as a guide. That is, the magnet floater 21 positions the stack 20 in the horizontal direction.
Further, as described above, when the lower work W1 is shaken off, the lower work W1 is positioned by the magnet floater 21 and is disposed at the top of the stack 20 that is kept immediately below. In order to position the lower workpiece W1 by the magnet floater 21, the acceleration of the uppermost workpiece W is suddenly stopped at an accelerated increase in a region surrounded by the magnet floater 21 (guide) in the horizontal direction.

The air blow 22 is a device that blows air toward the stack. The spraying method may be continuous or intermittent.
In the work holding mechanism 100, by blowing air toward the stack, a negative pressure is hardly generated between the uppermost work and the lower work. For this reason, a double blank is suppressed.
In particular, when an air cylinder 10 to be described later sucks and holds the uppermost workpiece W to accelerate and then suddenly stops and shakes down the lower workpiece W1, at the same time, between the uppermost workpiece W and the lower workpiece W1. By blowing air, the lower workpiece W1 can be effectively shaken off.

The air cylinder 10 includes a cylinder 11, a piston head 12 a inscribed in the cylinder 11, a piston 12 including a piston rod 12 b that is suspended from the piston head 12 a and extends out of the cylinder 11, and a piston Adsorbing means 13 attached to the lower end of the rod 12b.
Here, a space defined by the cylinder 11 and the piston head 12a is referred to as an upper space 15a, and a space defined by the cylinder 11 and the piston head 12a is referred to as a lower space 15b.

  The suction means 13 attached to the lower end of the piston 12 is an elastic dome-like elastic body, and the inside is decompressed by a suction means (not shown). That is, the suction means 13 sucks and holds the workpiece W by reducing the pressure inside. For this reason, the impact to a workpiece | work is reduced when adsorbing.

In the air cylinder 10, the upper space 15a and the lower space 15b are filled with air.
The cylinder 11 is provided with pressure adjusting means described later, and the pressure in the upper space 15a and the lower space 15b is changed by the pressure adjusting means. That is, in the air cylinder 10, the piston 12 moves up and down by giving a pressure difference between the upper space 15a and the lower space 15b. The pressure adjusting means will be described later.

According to the work holding mechanism 100, the piston 12 is suddenly stopped, whereby the lower work W1 in the case of double blanking collides with the uppermost work, and the downward force is exerted by the reaction. At the same time, repulsion between works due to magnetic force and repulsion between works due to air work, so the lower work W1 is surely shaken off.
Further, since the lower workpiece W1 falls in the region positioned on the magnet floater 21 (guide), it is guided by the guard when dropped. For this reason, the lower workpiece W1 is again arranged on the stack 20 without being displaced.

  Therefore, according to the workpiece holding mechanism according to the present embodiment, it is possible to suppress the occurrence of a double blank before conveyance by a simple method. For this reason, productivity can be stabilized.

Next, a work holding method using the above-described work holding mechanism 100 will be described.
The work holding method according to the present embodiment includes a descending start step, a descending contact step, an adsorption step, an ascending start step, a stopping step, and a re-raising step.
Hereinafter, each step will be described.

(Descent start step)
The descending start step is a step for starting the descending of the piston 12 by setting the atmospheric pressure in the lower space 15b to atmospheric pressure and increasing the atmospheric pressure in the upper space 15a to be greater than atmospheric pressure for a predetermined time.

FIG. 2 is a graph showing the relationship between the position in the height direction of the suction means 13 and time in the work holding method according to the present embodiment.
In the work adsorption method, the lowering of the piston 12 is started by setting the atmospheric pressure of the lower space 15b to atmospheric pressure and increasing the atmospheric pressure of the upper space 15a to be greater than the atmospheric pressure for a predetermined time t.
At this time, specifically, the atmospheric pressure in the upper space 15a is preferably 1.5 to 5 MPa, and more preferably 2 to 3 MPa.

Then, after the predetermined time t has elapsed, the atmospheric pressure in the upper space 15a and the lower space 15b is changed to atmospheric pressure. That is, the atmospheric pressure in the upper space 15a is returned to atmospheric pressure.
Then, since the atmospheric pressure in the upper space 15a and the lower space 15b becomes the same atmospheric pressure, the piston 12 naturally descends due to inertia and the gravity of the piston 12 itself.

(Descent contact step)
The descending contact step is a step of bringing the suction means 13 into contact with the uppermost workpiece W by lowering the piston 12 by its own weight with the atmospheric pressure in the upper space 15a and the lower space 15b set to atmospheric pressure after a predetermined time has elapsed. The time for starting the descending contact step is T1 (see FIG. 2).

FIG. 3A is a schematic diagram showing a state of the descending contact step in the work holding method according to the present embodiment.
As shown in FIG. 3A, when the suction means 13 connected to the lower end of the piston 12 reaches the position of the workpiece W, the suction means 13 and the workpiece W are brought into contact with each other.
At this time, the piston 12 is not moved down positively but is naturally moved down by inertia and the gravity of the piston 12 itself, so that the impact force applied to the workpiece W from the piston 12 is reduced.
Thereby, in the said workpiece | work holding method, it is suppressed that the workpiece | work W is damaged or deform | transformed. Moreover, it is hard to become a double blank.

(Adsorption step)
The suction step is a step for causing the suction means 13 to hold the workpiece W by suction. The time for starting the adsorption step is T2 (see FIG. 2).

In the suction step, the lowermost position (hereinafter also referred to as “bottom dead center”) of the suction holding means when the piston descends is the uppermost work in a state where no gap is formed between the work pieces in the stack. The position is set. When a magnetic force is applied by the magnet floater, several sheets from the uppermost workpiece have gaps between the workpieces.
Then, the suction means 13 descends to the bottom dead center (see FIG. 2) and the inside of the suction means 13 is depressurized, whereby the uppermost workpiece W is sucked and held by the suction means 13.

  In this case, the suction means 13 reliably holds and holds the workpiece W, and the force for pressing the workpiece W becomes as small as possible. Therefore, the gap between the workpieces W is not completely closed, and as a result, double blanks are generated. It can be suppressed more.

(Ascent start step)
The rising start step is a step of raising the piston by setting the atmospheric pressure in the upper space to atmospheric pressure and making the atmospheric pressure in the lower space larger than atmospheric pressure. The time for starting the ascending start step is T3 (see FIG. 2).

In the rising start step, the piston 12 is accelerated and raised by setting the atmospheric pressure in the upper space 15a to atmospheric pressure and increasing the atmospheric pressure in the lower space 15b to higher than atmospheric pressure.
At this time, specifically, the pressure in the lower space 15b is preferably 1.5 to 5 MPa, and more preferably 2 to 3 MPa.

(Stop step)
The stop step is a step of suddenly stopping the piston by setting the air pressure in the upper space to be the same as that in the lower space while the workpiece is positioned on the magnet floater (guide). The time for starting the stop step is T4 (see FIG. 2).

FIG. 3B is a schematic diagram showing a stop step state in the work holding method according to the present embodiment.
As shown in FIG. 3B, in the stop step, the acceleration increase of the piston 12 is suddenly stopped in the region R positioned on the magnet floater 21. This sudden stop is performed regardless of the presence or absence of a double blank.

At this time, in the stop step, a magnetic force is applied from the magnet floater 21 to the uppermost workpiece W, and at the same time, air is blown from the air blow 22 to the uppermost workpiece W. Note that the application of magnetic force and the blowing of air may be performed not only during the stop step but also at all times. That is, the magnetic force may be applied from the stage before the piston comes into contact with the workpiece W, or air may be blown.
Thereby, when the double blank has arisen, it will fall in the arrow A direction in the state in which the lower side workpiece | work W1 was positioned by the magnet floater 21, and will return to the original position.

(Re-rise step)
The re-raising step is a step of raising the piston by setting the atmospheric pressure in the upper space to atmospheric pressure and making the atmospheric pressure in the lower space larger than atmospheric pressure. The time for starting the re-rise step is T5 (see FIG. 2).

FIG. 3C is a schematic diagram illustrating a state of the re-raising step in the work holding method according to the present embodiment.
As shown in (c) of FIG. 3, the re-rise step is performed in the same manner as the above-described rise start step.

Thereafter, for example, the lifted work W is attracted to and conveyed by a magnetic conveyor disposed above the uppermost work W in the stack (not shown).
Further, the air cylinder 10 itself may be transported.

Here, in the work holding method, it is preferable that the time T1 from when the piston 12 starts to descend until the suction means 13 comes into contact with the work W and the predetermined time t satisfy the following expression.
In this case, the impact force applied to the workpiece W from the piston 12 can be reliably reduced. t ≦ 0.8T1
0 <t ≦ 0.5 (seconds)

When the atmospheric pressure in the upper space 15a is 1.5 to 5 MPa in the predetermined time, t is preferably 0.1 to 0.6 seconds, more preferably 0.3 to 0.5 seconds. preferable.
In this case, the piston 12 can be reliably lowered, and the impact force applied to the workpiece W from the piston 12 becomes smaller.

  At this time, the time from T2 to T3 (T3-T2) is preferably 0.2 to 0.5 seconds, and the time from T3 to T4 (T4-T3) is 0.1 to 0.2. The time from T4 to T5 (T5-T4) is preferably 0.3 to 0.5 seconds.

In the work holding method, the predetermined time t and the start times of the descent start step, the descent contact step, the suction step, the ascent start step, the stop step and the re-rise step are controlled by a timer.
Thus, since it is controlled by the timer, there is an advantage that it is possible to prevent variations in the timing at which the piston rises.

  According to the workpiece holding method according to the present embodiment, since the workpiece holding mechanism 100 described above is used, it is possible to suppress the occurrence of double blanks before conveyance by a simple method. For this reason, productivity can be stabilized.

Next, the pressure adjusting means of the workpiece holding mechanism 100 will be described.
FIG. 4 is a schematic view showing pressure adjusting means of the work holding mechanism according to the present embodiment.
As shown in FIG. 4, the pressure adjusting means of the work holding mechanism 100 is connected to the cylinder 11 so as to communicate with the upper space 15a, and an upper air inflow / outflow pipe 31a for flowing air into and out of the upper space 15a, and a lower space. A lower air inflow / outflow pipe 31b connected to the cylinder 11 so as to communicate with the lower space 15b, and a switching valve for switching air inflow / outflow to the upper air outflow / inflow pipe 31a and the lower air outflow / inflow pipe 31b. 30, an air inflow pipe 33 and an open pipe 32 connected to the switching valve 30, a compressor 35 connected to the air inflow pipe 33, and a silencer 34 connected to the open pipe 32. In addition, the said compressor 35 exhibits the function to flow in air, and the silencer 34 exhibits the noise reduction function at the time of flowing out air.

In the workpiece holding mechanism 100 according to the present embodiment, the piston 12 can be controlled to move up and down and suddenly stop by adjusting the pressure in the upper space 15a and the lower space 15b of the air cylinder 10.
In addition, an upper air inflow / outflow pipe 31a and a lower air inflow / outflow pipe 31b are provided for the inflow / outflow of air into the upper space 15a and the lower space 15b, and the inflow / outflow of air into these can be switched by the switching valve 30. Therefore, the piston 12 can be moved up and down and stopped suddenly.

A first speed controller 32a for controlling the outflow of air is attached to the upper air inflow / outflow pipe 31a. The first speed controller 32a provides a cushioning effect near the upper limit of the piston 12.
On the other hand, a second speed controller 32b for adjusting the air inflow speed and a third speed controller 32c for adjusting the air outflow speed are attached to the lower air inflow / outflow pipe 31b. The second speed controller 32b and the third speed controller 32c prevent the piston from moving up and down suddenly.

  Here, the 1st speed controller 32a, the 2nd speed controller 32b, and the 3rd speed controller 32c are the same mechanisms, and a well-known thing is used. In the work holding mechanism 100, the outflow of air in the upper air inflow / outflow pipe 31a is adjusted by the first speed controller 32a, whereas the inflow and outflow of air in the lower air inflow / outflow pipe 31b are respectively second. The speed controller 32b and the third speed controller 32c are separately adjusted.

Next, the relationship between the pressure adjusting means and the work holding method will be described.
In the descending start step of the work holding mechanism 100, the lower air inflow / outflow pipe 31b is connected to the open pipe 32 by the switching valve 30, thereby setting the atmospheric pressure in the lower space 15b to atmospheric pressure.
In addition, the upper air inflow / outflow pipe 31a is connected to the air inflow pipe 33 by the switching valve 30 and the air flows in from the compressor 35, so that the air pressure in the upper space 15a becomes larger than the atmospheric pressure for a predetermined time, thereby lowering the piston. To start.

  In the descending contact step, after a predetermined time elapses, the upper air inflow / outflow pipe 31a and the lower air inflow / outflow pipe 31b are connected to the open pipe 32 by the switching valve 30 and the pressure in the upper space 15a and the lower space 15b is atmospheric pressure. Is lowered to bring the uppermost workpiece W into contact with the suction means 13.

In the rising start step, the upper air inflow / outflow pipe 31a is connected to the open pipe 32 by the switching valve 30, and the atmospheric pressure in the upper space 15a is set to atmospheric pressure.
Further, the lower air inflow / outflow pipe 31b is connected to the air inflow pipe 33 by the switching valve 30, and the air is flowed in from the compressor 35, whereby the pressure of the lower space 15b is made larger than the atmospheric pressure, thereby accelerating and raising the piston.

  In the stop step, with the uppermost work W positioned on the magnet floater 21 (guide), the upper air inflow / outflow pipe 31a is connected to the air inflow pipe 33 by the switching valve 30 and air is allowed to flow in from the compressor 35. The piston 12 is stopped by making the atmospheric pressure of the upper space 15a the same as that of the lower space 15b.

  In the re-raising step, the upper air inflow / outflow pipe 31a is connected to the open pipe 32 by the switching valve 30, and the air pressure in the upper space 15a is set to atmospheric pressure to raise the piston.

  As described above, in the work holding mechanism 100, the upper air inflow / outflow pipe 31a and the lower air inflow / outflow pipe 31b are provided so that the air inflow / outflow can be switched by the switching valve 30. The piston 12 can be lowered naturally.

[Second Embodiment]
FIG. 5 is a front view schematically showing a workpiece holding mechanism according to another embodiment.
As shown in FIG. 5, the work holding mechanism 200 is provided with two air blows, and the air blown from one air blow 22 and the other air blow 22a is the uppermost work W and the lower one. It differs from the workpiece holding mechanism 100 according to the first embodiment described above in that it collides with the side workpiece W1. The other configuration of the work holding mechanism 200 according to the second embodiment is the same as that of the work holding mechanism 100 according to the first embodiment.

  That is, the work holding mechanism 200 includes the lifter 23, the stack 20 placed on the lifter 23, the guide 21 arranged in parallel to the stack 20 and positioning the work W, and applies a magnetic force to the stack 20. The magnet floater 21 to be held, the air cylinder 10 that holds the uppermost workpiece W of the stack 20 by suction and moves it upward, and the air cylinder 10 accelerates and raises the uppermost workpiece W and suddenly stops in the area surrounded by the magnet floater 21. The air blows between the uppermost work W and the lower work W1 and two air blows 22 and 22a provided so that the air collides with each other.

Each of the air blows 22 and 22a is a device that blows air toward the stack. The spraying method may be continuous or intermittent.
Since the work holding mechanism 200 is provided with two air blows 22 and 22a, the air blown from each air blow collides between the uppermost work W and the lower work W1 and collides. Air escapes up and down.
For this reason, since air pressure comes to work in the direction which separates uppermost work W and lower work W1, it becomes possible to control double blank more certainly.

  In addition, as for the workpiece holding method using the workpiece holding mechanism according to the second embodiment and the pressure adjusting means of the workpiece holding mechanism 200, the workpiece holding mechanism 200 according to the second embodiment includes two air blows 22 and 22a. Except for this, the workpiece holding method using the workpiece holding mechanism 100 according to the first embodiment and the pressure adjusting means of the workpiece holding mechanism 100 are the same.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

For example, in the workpiece holding mechanisms 100 and 200, the magnet floater 21 also serves as a guide, but the magnet floater and the guide may be separate.
In this case, the magnet floater 21 applies a magnetic force to the stack, and the guide positions the stack.
Further, when the lower work is shaken off, the lower work is positioned by the guide and arranged at the top of the stack. In order to position the lower workpiece with the guide, the acceleration of the uppermost workpiece is suddenly stopped in the region where the horizontal direction is surrounded by the guide.

  In the work holding mechanisms 100 and 200, the predetermined time and the time for raising the suction means after sucking and holding the work are controlled by the timer, but may be controlled by a method other than the timer.

  Further, the first speed controller 32a, the second speed controller 32b, the third speed controller 32c, and the silencer 34 in the work holding method are not necessarily essential components.

DESCRIPTION OF SYMBOLS 10 ... Air cylinder 11 ... Cylinder 12 ... Piston 12a ... Piston head 12b ... Piston rod 13 ... Adsorption means 15a ... Upper space 15b ... Lower space 20 ... Stack 21 ... Magnetic floater (guide)
22, 22a ... Air blow 23 ... Lifter 30 ... Switching valve 31a ... Upper air inflow / outflow pipe 31b ... Lower air inflow / outflow pipe 32 ... Opening pipe 32a ... First speed controller 32b ... Second speed controller 32c ... Third speed controller 33 ... Air inflow pipe 34 ... Silencer 35 ... Compressor 100, 200 ... Work holding mechanism A ... Arrow R ... Area T1, T2, T3, T4, T5 ... Time W ... Top work (work)
W1 ... Lower work (work)

Claims (10)

A workpiece holding mechanism for holding a workpiece from a stack in which a plurality of workpieces are stacked,
Stack,
A guide arranged side by side in the stack for positioning the workpiece;
A magnet floater that applies magnetic force to the stack;
An air cylinder that holds the uppermost workpiece of the stack by suction and moves it upward;
When the air cylinder accelerates and raises the uppermost workpiece, and suddenly stops in the area surrounded by the guide, an air blow for flowing air between the uppermost workpiece and the workpiece below the workpiece;
A workpiece holding mechanism.   The work holding mechanism according to claim 1, wherein the stack is placed on a lifter.   The work holding mechanism according to claim 1 or 2, wherein a plurality of the air blows are provided, and the air blown from each air blow collides between the uppermost work and a work below the work.   The work holding mechanism according to claim 1, wherein the magnet floater also serves as the guide. The air cylinder is attached to a cylinder, a piston consisting of a piston head inscribed in the cylinder, a piston rod suspended from the piston head and connected to extend out of the cylinder, and a lower end of the piston rod. An adsorbing means, and an upper space defined by the cylinder and the piston head, and a pressure adjusting means for adjusting the pressure in the lower space defined by the cylinder and the piston head,
The pressure adjustment means moves the piston up and down,
The workpiece holding mechanism according to claim 1, wherein the suction unit holds the workpiece by suction. An upper air inflow / outflow pipe connected to the cylinder so as to communicate with the upper space, and for flowing air into and out of the upper space;
A lower air inflow / outflow pipe connected to the cylinder so as to communicate with the lower space and for flowing air into and out of the lower space;
A switching valve for switching the flow of air into and out of the upper air inflow / outflow pipe and the lower air outflow / inflow pipe,
An air inflow pipe and an open pipe connected to the switching valve;
A compressor connected to the air inlet pipe;
The workpiece holding mechanism according to claim 5, further comprising: A workpiece holding method using the workpiece holding mechanism according to claim 5,
By lowering the atmospheric pressure in the lower space to atmospheric pressure and increasing the atmospheric pressure in the upper space above atmospheric pressure for a predetermined time, the piston starts to descend, and after the predetermined time has elapsed, the atmospheric pressure in the upper space and the lower space is reduced. A descent start step for lowering the piston in an atmospheric pressure state;
A lowering abutting step for abutting the suction means on the workpiece;
An adsorption step for causing the adsorption means to adsorb and hold the workpiece;
A rising start step for accelerating and raising the piston by setting the atmospheric pressure in the upper space to atmospheric pressure and making the atmospheric pressure in the lower space larger than atmospheric pressure;
A stop step of suddenly stopping the piston by making the air pressure in the upper space the same as that in the lower space in a state where the guide is positioned;
Then, a re-rising step for raising the piston by setting the atmospheric pressure in the upper space to atmospheric pressure and making the atmospheric pressure in the lower space larger than atmospheric pressure;
A work holding method comprising: A workpiece holding method using the workpiece holding mechanism according to claim 6,
The lower air inflow / outflow pipe is connected to the open pipe by the switching valve, the atmospheric pressure in the lower space is set to atmospheric pressure, the upper air inflow / outflow pipe is connected to the air inflow pipe by the switching valve, and air flows from the compressor. A lowering start step for starting lowering of the piston by making the atmospheric pressure of the upper space larger than atmospheric pressure for a predetermined time by
After the predetermined time has elapsed, the upper air inflow / outflow pipe and the lower air inflow / outflow pipe are connected to an open pipe by the switching valve, and the piston is lowered while the pressure in the upper space and the lower space is atmospheric pressure, and the adsorption is performed. A descending contact step for contacting the workpiece with the means;
An adsorption step for causing the adsorption means to adsorb and hold the workpiece;
The upper air inflow / outflow pipe is connected to the open pipe by the switching valve, the atmospheric pressure in the upper space is set to atmospheric pressure, the lower air inflow / outflow pipe is connected to the air inflow pipe by the switching valve, and air flows from the compressor. A rising start step for accelerating and raising the piston by making the atmospheric pressure in the lower space larger than atmospheric pressure,
With the workpiece positioned on the guide, the upper air inflow / outflow pipe is connected to the air inflow pipe by the switching valve, and air is allowed to flow in from the compressor so that the air pressure in the upper space is changed to the lower space. A stopping step for suddenly stopping the piston by making the same;
Thereafter, the upper air inflow / outflow pipe is connected to the open pipe by the switching valve, the atmospheric pressure in the upper space is set to atmospheric pressure, and a re-raising step for raising the piston;
A work holding method comprising:   The work holding method according to claim 7 or 8, wherein all of the descending start step, the descending contact step, the suction step, the ascending start step, the stopping step, and the re-raising step are controlled by a timer.   The lower limit position of the suction holding means when the piston descends is set to the position of the uppermost workpiece in a state where no gap is formed between the workpieces of the stack. The work holding method described.

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