A rapid air cushion exhaust and ejection device for a press and its working method

Abstract

This invention discloses a rapid air cushion exhaust and ejection device for a press and its working method, within the field of presses. The device includes a press body with a reciprocating slide block. A crankshaft connecting rod mechanism, connected to the slide block, is located on the upper part of the press body. A position encoder is mounted on the crankshaft corresponding to the crankshaft connecting rod mechanism on the press body. An upper template is located below the slide block, and an upper die is mounted on the upper template. A lower template is located on the press body corresponding to the slide block, and a lower die is mounted on the lower template. The upper and lower dies are vertically aligned. A PLC control unit is located on the press body. An air cushion is vertically positioned below the lower template on the press body. This invention enables rapid exhaust of gas from the air cushion via a nitrogen cylinder and a rapid exhaust solenoid valve, preventing incomplete exhaust of the air cushion before punching and ensuring continuous and efficient operation during the stamping process.

Description

Technical Field

[0001] This invention belongs to the field of presses, and specifically relates to a press air cushion rapid exhaust and ejection device and its working method. Background Technology

[0002] In existing technologies, air cushion devices are frequently used in metal stamping processes to eject material and achieve stamping. During the air cushion's dropping motion, a rapid venting device must be used to ensure that the air pressure inside the air cushion is completely released after stamping; otherwise, it can cause workpiece deformation or defects. Because the punch of a mechanical press reciprocates at a relatively high speed, it cannot stop at the bottom dead center during continuous or single stamping. After the punch finishes stamping the workpiece once, the air cushion ejects the workpiece, but before the punch performs a second stamping, the air cushion cannot completely release pressure. This abnormal ejection of material by the air cushion during punching results in a low product yield. Customers often need to invest in servo presses or hydraulic presses, but these have the following disadvantages: 1. Existing mechanical presses have a low yield rate; 2. Servo presses are expensive, while hydraulic presses are too slow, affecting the stamping efficiency of the press. Summary of the Invention

[0003] One of the objectives of this invention is to provide a press air cushion rapid exhaust and ejection device, which can quickly exhaust the gas in the air cushion through a nitrogen cylinder and a fast exhaust solenoid valve of the air cushion, preventing abnormal ejection caused by the air cushion not being fully depressurized before the punch is pressed, and ensuring the continuity and efficiency of the action during the pressing process.

[0004] The objective of this invention is achieved as follows: A rapid air cushion exhaust and ejection device for a press includes a press body. A slide block capable of reciprocating up and down is mounted on the press body. A crankshaft connecting rod mechanism, which is connected to the slide block, is mounted on the upper part of the press body. A position encoder is mounted on the crankshaft corresponding to the crankshaft connecting rod mechanism on the press body. An upper template is mounted below the slide block, and an upper die is mounted on the upper template. A lower template is mounted on the press body corresponding to the slide block, and the upper and lower dies are vertically aligned. A PLC control unit is mounted on the press body. The press body has an air cushion vertically installed below the lower template. The lower template has a through hole, and a movable top block is installed inside the through hole. The lower part of the top block is supported on the lifting end of the air cushion, and the upper part of the top block is set corresponding to the lower mold. The lower template has at least two mounting holes, and a nitrogen cylinder is vertically installed in the mounting holes. The piston rod of the nitrogen cylinder passes through the lower template and abuts against the lifting end of the air cushion. A pressure feedback unit is installed corresponding to the air cushion. The air inlet of the air cushion is connected to the air storage tank through a pipe, and a quick exhaust solenoid valve is installed on the pipe.

[0005] When the air cushion of the present invention is working, the air tank fills the lower chamber of the air cushion with air. The gas enters the middle chamber and the upper chamber through the main channel, side channel one, and side channel two, pushing the upper piston to drive the top block and the top rod to rise. After the workpiece is stamped, the top rod passes through the hole of the lower die and ejects the workpiece. Before the slider moves down from the top dead center to stamp the workpiece, the quick exhaust solenoid valve opens, and the lower chamber of the air cushion exhausts gas. Then, before the slider reaches the bottom dead center, the nitrogen cylinder presses down the upper piston, so that the gas in the upper chamber and the middle chamber enters the lower chamber and is discharged from the air cushion through side channel one, side channel two, and the main channel. The top rod descends, thereby avoiding abnormal ejection of the material by the top rod when the upper die reaches the bottom dead center. The piston rod one of the nitrogen cylinder remains in contact with the upper piston, and the piston rod one rises and falls with the rise and fall of the upper piston. Compared with the prior art, the beneficial effects of the present invention are as follows: the gas in the air cushion can be quickly discharged through the nitrogen cylinder and the quick discharge solenoid valve of the air cushion, preventing abnormal ejection caused by the air cushion not being fully discharged before the punch is pressed, thus ensuring the continuity and efficiency of the action during the stamping process.

[0006] As a further improvement of the present invention, the through hole is opened in the middle of the lower template, and a push rod is provided between the top block and the upper template. A limit groove is opened on the upper part of the top block, and the lower end of the push rod is inserted into the limit groove. The upper end of the push rod is set corresponding to the upper template. At least one bottom dead point switch of the mold top block is provided on the push rod, and the bottom dead point switch of the mold top block is a limit switch. A hole is opened in the part of the lower mold that needs to eject the material, and then the push rod passes through the hole of the lower mold to eject the workpiece. The lower end of the push rod rests on the top block. The push rod is lifted or lowered with the top block. The limit groove limits the push rod to prevent the push rod from tilting. The slider descends to press the workpiece. The crankshaft angle signal collected in real time by the position encoder is detected. When the crankshaft rotation angle of the press is at the secondary exhaust position, the upper mold has pressed the workpiece, and the bottom dead point switches of each mold top block receive the signal.

[0007] As a further improvement of the present invention, the pressure feedback unit is a pressure sensor for detecting the gas pressure inside the air cushion. The pressure feedback unit, position encoder, quick-release solenoid valve, clutch power supply of the crankshaft drive motor of the crankshaft connecting rod mechanism, and bottom dead center switches of each mold top block are all electrically connected to the PLC control unit. The pressure feedback unit is connected to the inside of the air cushion via a pressure detection tube to detect the gas pressure inside the air cushion.

[0008] As a further improvement of the present invention, the central axes of the top block and the air cushion coincide, and the at least two mounting holes are symmetrically distributed on both sides of the top block. The mounting holes are stepped holes, including a large-diameter hole, a medium-diameter hole, and a small-diameter hole distributed sequentially from top to bottom. The cylinder body of the nitrogen cylinder is disposed in the medium-diameter hole, and the piston rod of the nitrogen cylinder passes downward through the small-diameter hole and abuts against the lifting end of the air cushion. The outer diameter of the piston rod of the nitrogen cylinder is smaller than the inner diameter of the small-diameter hole. A pressure cap is fixedly disposed in the large-diameter hole to press down the cylinder body of the nitrogen cylinder. The nitrogen cylinder is installed in the mounting hole.

[0009] As a further improvement of the present invention, the air cushion includes a cylindrical outer shell, a lower end plate at the lower end of the outer shell, and an annular outer step at the upper end of the outer shell. Two layers of spaced-apart partitions are fixedly installed inside the outer shell, each partition having a guide hole at its center. A piston rod 2 is vertically fitted through the two guide holes. The outer shell is divided into an upper chamber, a middle chamber, and a lower chamber sequentially by the two partitions. An upper piston, a middle piston, and a lower piston are respectively installed on the piston rod 2. An annular limiting step 1 and a limiting step 2 are respectively provided on the outer periphery of the piston rod 2. The middle piston and the lower piston are both fitted onto the piston rod 2, with the upper ends of the middle piston and the lower piston respectively abutting against the limiting step 1 and the limiting step 2. The outer periphery of the piston rod 2 corresponds to the middle piston. A locking nut is fitted onto the lower end of the piston and the lower piston. The upper piston is fixed to the upper end of the piston rod. The upper piston, middle piston, and lower piston are respectively fitted into the upper chamber, middle chamber, and lower chamber. A vertical main channel is opened in the middle of the piston rod, and the lower end of the main channel is connected to the lower chamber. At least two symmetrical side channels, one and two, are opened on both sides of the main channel on the piston rod. Both side channels one are connected to the upper chamber, and both side channels two are connected to the middle chamber. At least two symmetrically distributed shock-absorbing screws are provided at the lower end of the middle piston and the lower piston. A shock-absorbing pad is provided at the lower end of the shock-absorbing screw. The pipe is connected to the lower chamber. The piston rod of the nitrogen cylinder elastically abuts against the upper piston. The upper piston moves up and down within the upper chamber of the air cushion. The shock-absorbing pads provide shock absorption for the middle piston and the lower piston. The outer step is fixed to the edge of the lower end plate by several circumferentially distributed screws. The upper piston is fixed to the upper end of the piston rod by axial screws.

[0010] The second objective of this invention is to provide a working method for a press air cushion rapid exhaust and ejection device, which can de-energize the clutch of the crankshaft drive motor during the pressing process of a mechanical press, causing the press slide to pause for a few seconds before the bottom dead center. Through the nitrogen cylinder and the fast exhaust solenoid valve of the air cushion, the gas in the air cushion is quickly discharged, thereby ensuring the continuity of action during the stamping process, the high efficiency of stamping, reducing equipment cost investment and improving efficiency.

[0011] The objective of this invention is achieved as follows: a method for operating a press air cushion rapid exhaust and ejection device includes the following steps:

[0012] (1) The PLC control unit of the press controls the press to enter the preparation for punching, so that the slide of the press is at the top dead center position, and the crankshaft of the crankshaft connecting rod mechanism that drives the slide of the press is at the 0 degree position.

[0013] (2) The PLC control unit of the press controls the slide of the machine tool to press down. At this time, the fast exhaust solenoid valve is de-energized and opens. The air cushion exhausts the air into the air tank. At the same time, the position encoder collects the crankshaft angle signal in real time.

[0014] (3) The robot places the workpiece to be stamped onto the lower die. The robot is connected to the PLC control unit of the press. The robot then turns on the two-hand button switch of the press to trigger the start signal of the press. Only after the two-hand button switch is turned on can the press slide continue to press down. Otherwise, the slide cannot continue to press down. The two-hand button switch plays a safety protection role.

[0015] (4) The PLC control unit of the press controls the slide of the press to descend and press the workpiece. At the same time, it detects the crankshaft angle signal collected in real time by the position encoder in step (2). When the crankshaft rotation angle of the press is in the secondary exhaust position, the upper die has pressed the workpiece. The bottom dead point switch of each die block receives the signal. At the same time, the bottom dead point switch of each die block is compared with the real-time signal of the position encoder. When the real-time signal of the position encoder is also in the secondary exhaust position, it feeds back to the PLC control unit and disconnects the clutch power supply.

[0016] (5) After the clutch power is de-energized, the slider continues to descend towards the bottom dead center under the action of inertia. Before the slider reaches the bottom dead center, the clutch power is de-energized and waits for 1-5 seconds. The PLC control unit of the press is equipped with a touch screen that can control the waiting time of the clutch power de-energized. After the quick exhaust solenoid valve is opened, the gas in the lower chamber of the air cushion is discharged. The air pressure of the first piston rod of the nitrogen cylinder is removed. The first piston rod of the nitrogen cylinder moves downward and presses down the upper piston. Before the slider reaches the bottom dead center, the first piston rod of the nitrogen cylinder presses out the residual gas in the upper chamber and middle chamber of the air cushion. After the air cushion is completely vented, the pressure feedback unit detects the corresponding pressure signal and feeds it back to the PLC control unit. The PLC control unit automatically restores the running signal, the clutch power is energized, and the slider continues to run until it reaches the top dead center. After the slider leaves the bottom dead center, the quick exhaust solenoid valve is energized, and the air tank fills the air cushion. Before the slider reaches the top dead center, the upper piston pushes the top block up, and the top rod pushes out the workpiece. The ejection is completed.

[0017] (6) The crankshaft of the press is at 0 degrees at this time. When the next workpiece needs to be stamped, the steps (2)-(5) are repeated. When the workpiece does not need to be stamped, the crankshaft of the press remains stationary and is in standby mode.

[0018] The working method of this invention records the working state of the air cushion during the complete cycle of the crankshaft rotating from 0 degrees to 0 degrees. Compared with the prior art, the beneficial effects of this invention are: it can de-energize the clutch of the crankshaft drive motor during the pressing process of the mechanical press, and the press slide pauses for a few seconds before the bottom dead center. Through the nitrogen cylinder and the quick-release solenoid valve of the air cushion, the gas in the air cushion is quickly discharged, thereby ensuring the continuity of action in the stamping process, the high efficiency of stamping, reducing equipment cost investment and improving efficiency.

[0019] As a further improvement of the present invention, the secondary exhaust position of the press crankshaft is such that the crankshaft rotation angle is 165 degrees to 170 degrees.

[0020] As a further improvement of the present invention, when the bottom dead center switch of each mold top block receives a signal, if the real-time signal of the position encoder is not in the secondary venting position, the PLC control unit of the press will issue an alarm signal and stop subsequent stamping; when the real-time signal of the position encoder is adjusted to the secondary venting position, the press's two-hand push-button switch must be turned on again to trigger the press start signal before stamping can continue. The bottom dead center switch detection signal of the mold top block and the position encoder angle are interlocked. The PLC control unit will disconnect the clutch power supply only when both conditions are met; otherwise, the control unit will alarm.

[0021] As a further improvement of the present invention, the press body is equipped with a key switch and an operation indicator light for controlling the operation of the air cushion. When the key switch is turned on, the air cushion operates; the operation indicator light displays the operating status of the air cushion. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention.

[0023] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0024] Figure 3 This is a schematic diagram of the piston rod 2.

[0025] Figure 4 This is a cross-sectional view of one side passage of piston rod two.

[0026] Figure 5 This is a control principle diagram of the PLC control unit for the press of the present invention.

[0027] The components include: 1. Press body; 2. Slider; 3. Position encoder; 4. Upper platen; 5. Upper die; 6. Lower platen; 7. Lower die; 8. PLC control unit, 9 air cushion, 901 outer casing, 902 lower end plate, 903 outer step, 904 partition, 905 guide hole, 906 piston rod II, 906a main channel, 906b side channel I, 906c side channel II, 907 upper chamber, 908 middle chamber, 909 lower chamber, 910 upper piston, 911 middle piston, 912 lower piston, 913 limit step I, 914 limit step II, 915 locking nut, 916 damping screw, 916a damping pad, 10 through hole, 11 top block, 12 mounting hole, 12a large diameter hole, 12b middle diameter hole, 12c small diameter hole, 13 nitrogen cylinder, 13a piston rod I, 14 pressure feedback unit, 15 pipe, 16 air tank, 17 quick exhaust solenoid valve, 18 top rod, 19 limit groove, 20 mold top block bottom dead point switch, 21 pressure cap. Detailed Implementation Example 1

[0028] like Figure 1-5 As shown, the press air cushion rapid exhaust and ejection device of this embodiment includes a press body 1, a slider 2 that can move up and down reciprocally is provided on the press body 1, a crankshaft connecting rod mechanism that is connected to the slider 2 is provided on the upper part of the press body 1, a position encoder 3 is provided on the crankshaft of the press body 1 corresponding to the crankshaft connecting rod mechanism, an upper template 4 is provided at the lower part of the slider 2, an upper mold 5 is installed on the upper template 4, a lower template 6 is provided on the press body 1 corresponding to the slider 2, a lower mold 7 is installed on the lower template 6, the upper mold 5 and the lower mold 7 are arranged vertically correspondingly, a PLC control unit 8 is provided on the press body 1, and the lower mold is located on the press body 1. An air cushion 9 is vertically installed below the plate 6. A through hole 10 is opened on the lower template 6. A top block 11 that can move up and down is installed in the through hole 10. The lower part of the top block 11 is supported on the lifting end of the air cushion 9. The upper part of the top block 11 is set corresponding to the lower mold. At least two mounting holes 12 are opened on the lower template 6. A nitrogen cylinder 13 is vertically installed in the mounting hole 12. The piston rod 13a of the nitrogen cylinder 13 passes downward through the lower template 6 and abuts against the lifting end of the air cushion 9. A pressure feedback unit 14 is set corresponding to the air cushion 9. The air inlet of the air cushion 9 is connected to the air storage tank 16 through the pipe 15. A quick exhaust solenoid valve 17 is installed on the pipe 15.

[0029] A through hole 10 is opened in the middle of the lower mold plate 6. A push rod 18 is provided between the top block 11 and the upper mold plate 4. A limit groove 19 is opened on the upper part of the top block 11. The lower end of the push rod 18 is inserted into the limit groove 19. The upper end of the push rod 18 is set corresponding to the upper mold plate 4. At least one mold top block bottom dead point switch 20 is provided on the push rod 18. The mold top block bottom dead point switch 20 is a limit switch. A hole is opened in the part of the lower mold that needs to eject the material. Then the push rod 18 passes through the hole of the lower mold to eject the workpiece. The lower end of the push rod 18 rests on the top block 11. The push rod 18 is lifted or lowered with the top block 11. The limit groove 19 limits the push rod 18 to prevent the push rod 18 from tilting. The slider 2 descends to press the workpiece. The crankshaft angle signal collected in real time by the position encoder 3 is detected. When the crankshaft rotation angle of the press is in the secondary exhaust position, the upper mold has pressed the workpiece. The bottom dead point switches 20 of each mold top block receive the signal. The pressure feedback unit 14 is a pressure sensor that detects the gas pressure inside the air cushion 9. The pressure feedback unit 14, the position encoder 3, the quick-release solenoid valve 17, the clutch power supply of the crankshaft drive motor of the crankshaft connecting rod mechanism, and the bottom dead center switch 20 of each mold top block are all electrically connected to the PLC control unit 8. The pressure feedback unit 14 is connected to the inside of the air cushion 9 through a pressure detection tube to detect the air pressure inside the air cushion 9.

[0030] The central axes of the top block 11 and the air cushion 9 coincide. At least two mounting holes 12 are symmetrically distributed on both sides of the top block 11. The mounting holes 12 are stepped holes, including a large-diameter hole 12a, a medium-diameter hole 12b, and a small-diameter hole 12c arranged sequentially from top to bottom. The cylinder body of the nitrogen cylinder 13 is disposed within the medium-diameter hole 12b. The piston rod 13a of the nitrogen cylinder 13 passes downward through the small-diameter hole 12c and abuts against the lifting end of the air cushion 9. The outer diameter of the piston rod 13a of the nitrogen cylinder 13 is smaller than the inner diameter of the small-diameter hole 12c. A pressure cap 21 is fixedly disposed within the large-diameter hole 12a to press down the cylinder body of the nitrogen cylinder 13. The nitrogen cylinder 13 is installed within the mounting holes 12.

[0031] The air cushion 9 includes a cylindrical outer shell 901. The lower end of the outer shell 901 has a lower end plate 902, and the upper end of the outer shell 901 has an annular outer step 903. Two layers of spaced-apart partitions 904 are fixedly installed inside the outer shell 901. Each partition 904 has a guide hole 905 at its center. A piston rod 906 is vertically inserted through the two guide holes 905. The outer shell 901 is divided into an upper chamber 907, a middle chamber 908, and a lower chamber 904 sequentially via the two partitions 904. 9. An upper piston 910, a middle piston 911, and a lower piston 912 are respectively mounted on piston rod 2 906. An annular limiting step 1 913 and a limiting step 2 914 are respectively provided on the outer periphery of piston rod 2 906. The middle piston 911 and the lower piston 912 are both fitted onto piston rod 2 906. The upper ends of the middle piston 911 and the lower piston 912 abut against limiting step 1 913 and limiting step 2 914 respectively. The outer periphery of piston rod 2 906 corresponds to the middle piston 911 and the lower piston 912. 2. A locking nut 915 is fitted onto the lower end of each piston rod 906. The upper piston 910 is fixed to the upper end of the piston rod 906. The upper piston 910, middle piston 911, and lower piston 912 are respectively fitted into the upper chamber 907, middle chamber 908, and lower chamber 909. A vertical main channel 906a is opened in the middle of the piston rod 906. The lower end of the main channel 906a is connected to the lower chamber 909. At least one locking nut 915 is opened on both sides of the main channel 906a on the piston rod 906. Two symmetrical side channels 906b and 906c are provided. Both side channels 906b are connected to the upper chamber 907, and both side channels 906c are connected to the middle chamber 908. The lower ends of the middle piston 911 and the lower piston 912 are provided with at least two symmetrically distributed shock-absorbing screws 916. The lower ends of the shock-absorbing screws 916 are provided with shock-absorbing pads 916a. The pipe 15 is connected to the lower chamber 909. The piston rod 13a of the nitrogen cylinder 13 elastically abuts against the upper piston 910. The upper piston 910 moves up and down within the stroke of the upper chamber 907 of the air cushion 9. The shock-absorbing pads 916a provide shock absorption for the middle piston 911 and the lower piston 912. The outer step 903 is fixed to the edge of the lower end plate 902 by several circumferentially distributed screws. The upper piston 910 is fixed to the upper end of the piston rod by axial screws.

[0032] When the air cushion 9 of the present invention is working, the air tank 16 fills the lower chamber 909 of the air cushion 9 with air. The gas enters the middle chamber 908 and the upper chamber 907 through the main channel 906a, side channel one 906b, and side channel two 906c, pushing the upper piston 910 to drive the top block 11 and the ejector rod 18 to rise. After the workpiece is stamped, the ejector rod 18 passes through the hole of the lower die and ejects the workpiece. Before the slider 2 moves downward from the top dead center to stamp the workpiece, the quick exhaust solenoid valve 17 opens, and the lower chamber 909 of the air cushion 9 exhausts gas outward. Before the slider 2 reaches the bottom dead center, the nitrogen cylinder 13 presses down on the upper piston 910, causing the gas in the upper chamber 907 and the middle chamber 908 to enter the lower chamber 909 and exit the air cushion 9 through the side channel 1 906b, the side channel 2 906c, and the main channel 906a. The ejector rod 18 then descends, thus preventing abnormal ejection of material by the ejector rod 18 when the upper die reaches the bottom dead center. The piston rod 13a of the nitrogen cylinder 13 remains in contact with the upper piston 910, and rises and falls with the upper piston 910. This invention can quickly discharge the gas in the air cushion 9 through the nitrogen cylinder 13 and the quick-release solenoid valve 17 of the air cushion 9, preventing abnormal ejection caused by incomplete pressure release of the air cushion 9 before the punch presses, ensuring the continuity and efficiency of the stamping process. Example 2

[0033] The working method of the press air cushion rapid exhaust and ejection device in this embodiment includes the following steps:

[0034] (1) The PLC control unit 8 of the press controls the press to enter the preparation for punching, so that the slide 2 of the press is at the top dead center position, and the crankshaft of the crankshaft connecting rod mechanism that drives the slide 2 on the press is at the 0 degree position.

[0035] (2) The PLC control unit 8 of the press controls the slide 2 of the machine tool to press down. At this time, the fast exhaust solenoid valve 17 is de-energized and the fast exhaust solenoid valve 17 is opened. The air cushion 9 exhausts the air into the air tank 16. At the same time, the position encoder 3 collects the crankshaft angle signal in real time.

[0036] (3) The robot places the workpiece to be stamped onto the lower die. The robot is connected to the PLC control unit 8 of the press. The robot then turns on the two-hand button switch of the press to trigger the start signal of the press. Only after the two-hand button switch is turned on can the press slide 2 continue to press down. Otherwise, the slide 2 cannot continue to press down. The two-hand button switch plays a safety protection role.

[0037] (4) The PLC control unit 8 of the press controls the slide 2 of the press to descend and press the workpiece. At the same time, it detects the crankshaft angle signal collected in real time by the position encoder 3 in step (2). When the crankshaft rotation angle of the press is in the secondary exhaust position, the upper die has pressed the workpiece. The bottom dead point switch 20 of each die block receives the signal. At the same time, the bottom dead point switch 20 of each die block compares with the real-time signal of the position encoder 3. When the real-time signal of the position encoder 3 is also in the secondary exhaust position, it feeds back to the PLC control unit 8 and disconnects the clutch power supply.

[0038] (5) After the clutch power is lost, the slider 2 continues to descend towards the bottom dead center under the action of inertia. Before the slider 2 reaches the bottom dead center, the clutch power is lost for 1-5 seconds. The PLC control unit 8 of the press is equipped with a touch screen that can control the clutch power loss waiting time. After the quick discharge solenoid valve 17 is opened, the gas in the lower chamber 909 of the air cushion 9 is discharged, and the air pressure of the piston rod 13a of the nitrogen cylinder 13 is removed. The piston rod 13a of the nitrogen cylinder 13 moves downward and presses down the upper piston 910. Before the slider 2 reaches the bottom dead center, the piston of the nitrogen cylinder 13... Rod 13a forces out the residual gas in the upper cavity and middle cavity 908 of the air cushion 9. After the air cushion 9 is completely vented, the pressure feedback unit 14 detects the corresponding pressure signal and feeds it back to the PLC control unit 8. The PLC control unit 8 automatically restores the running signal, the clutch power is energized, and the slider 2 continues to run until it reaches the top dead center. After the slider 2 leaves the bottom dead center, the quick exhaust solenoid valve 17 is energized, and the air tank 16 fills the air cushion 9 with air. Before the slider 2 reaches the top dead center, the upper piston 910 pushes the top block 11 upward, and the push rod 18 pushes out the workpiece, completing the ejection process.

[0039] (6) The crankshaft of the press is at 0 degrees at this time. When the next workpiece needs to be stamped, the steps (2)-(5) are repeated. When the workpiece does not need to be stamped, the crankshaft of the press remains stationary and is in standby mode.

[0040] The secondary venting position of the press crankshaft is when the crankshaft rotation angle is 165-170 degrees. When the bottom dead center switch 20 of each mold top block receives a signal, if the real-time signal of the position encoder 3 is not in the secondary venting position, the PLC control unit 8 of the press will issue an alarm signal and stop subsequent stamping; when the real-time signal of the position encoder 3 is adjusted to the secondary venting position, the press's two-hand push-button switch must be turned on again to trigger the press start signal before stamping can continue. The detection signal of the bottom dead center switch 20 of the mold top block and the angle of the position encoder 3 are interlocked. The PLC control unit 8 will disconnect the clutch power supply only when both conditions are met; otherwise, the control unit will alarm.

[0041] The press body 1 is equipped with a key switch and an operation indicator light for controlling the operation of the air cushion 9. When the key switch is turned on, the air cushion 9 operates; the operation indicator light shows the operating status of the air cushion 9.

[0042] The working method of this invention records the working state of the air cushion 9 during the crankshaft's complete rotation from 0 degrees to 0 degrees and then to a complete cycle. This invention can de-energize the clutch of the crankshaft's drive motor during the pressing process of a mechanical press, causing the press slide 2 to pause for a few seconds before the bottom dead center. Through the nitrogen cylinder 13 and the quick-release solenoid valve 17 of the air cushion 9, the gas inside the air cushion 9 is quickly discharged, thereby ensuring the continuity of action during the stamping process, the high efficiency of stamping, reducing equipment costs, and improving efficiency.

[0043] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A rapid air cushion exhaust and ejection device for a press, comprising a press body, a slide block that can reciprocate up and down on the press body, a crankshaft connecting rod mechanism connected to the slide block on the upper part of the press body, a position encoder on the crankshaft corresponding to the crankshaft connecting rod mechanism on the press body, an upper template on the lower part of the slide block, an upper die mounted on the upper template, a lower template on the press body corresponding to the slide block, a lower die mounted on the lower template, the upper and lower dies being vertically corresponding, a PLC control unit on the press body, and an air cushion vertically disposed on the press body below the lower template, characterized in that... The lower template has a through hole, and a movable top block is fitted inside the through hole. The lower part of the top block is supported on the lifting end of the air cushion, and the upper part of the top block corresponds to the lower mold. The lower template has at least two mounting holes, and a nitrogen cylinder is vertically installed in each mounting hole. The piston rod of the nitrogen cylinder passes downward through the lower template and abuts against the lifting end of the air cushion. A pressure feedback unit is installed corresponding to the air cushion. The air cushion's air inlet is connected to a gas storage tank through a pipe, and a quick-release solenoid valve is installed on the pipe. The central axes of the top block and the air cushion coincide. Symmetrically distributed on both sides of the top block, the mounting holes are stepped holes, including a large-diameter hole, a medium-diameter hole, and a small-diameter hole arranged sequentially from top to bottom. The cylinder body of the nitrogen cylinder is set in the medium-diameter hole, and the piston rod of the nitrogen cylinder passes downward through the small-diameter hole and abuts against the lifting end of the air cushion. The outer diameter of the piston rod of the nitrogen cylinder is smaller than the inner diameter of the small-diameter hole. A pressure cap is fixedly installed in the large-diameter hole to press down the cylinder body of the nitrogen cylinder. The air cushion includes a cylindrical outer shell with a lower end plate at the lower end and an annular outer step at the upper end. Two layers of spaced partitions are fixedly installed inside the outer shell. Each piston has guide holes, and the piston rod 2 is vertically inserted through the two guide holes. The outer casing is divided into an upper chamber, a middle chamber, and a lower chamber by two partitions. An upper piston, a middle piston, and a lower piston are mounted on the piston rod 2. An annular limiting step 1 and a limiting step 2 are respectively provided on the outer circumference of the piston rod 2. The middle piston and the lower piston are both fitted onto the piston rod 2, with the upper ends of the middle piston and the lower piston respectively abutting against the limiting step 1 and the limiting step 2. A locking nut is fitted on the outer circumference of the piston rod 2 corresponding to the lower ends of the middle piston and the lower piston. The upper piston is fixed to the upper end of the piston rod 2. The upper piston, middle piston, and lower piston... The piston rod and the lower piston are respectively installed in the upper chamber, the middle chamber, and the lower chamber. A vertical main channel is opened in the middle of the piston rod, and the lower end of the main channel is connected to the lower chamber. At least two symmetrical side channels one and two are opened on both sides of the main channel on the piston rod. Both side channels one are connected to the upper chamber, and both side channels two are connected to the middle chamber. At least two symmetrically distributed shock-absorbing screws are provided at the lower end of the middle piston and the lower piston. The shock-absorbing pads are provided at the lower end of the shock-absorbing screws. The pipe is connected to the lower chamber, and the piston rod one of the nitrogen cylinder elastically abuts against the upper piston.

2. The press air cushion rapid exhaust and ejection device according to claim 1, characterized in that, The through hole is located in the middle of the lower template. A push rod is provided between the top block and the upper template. A limit groove is provided on the upper part of the top block. The lower end of the push rod is inserted into the limit groove. The upper end of the push rod is set corresponding to the upper template. At least one bottom dead point switch of the mold top block is provided on the push rod. The bottom dead point switch of the mold top block is a limit switch.

3. The press air cushion rapid exhaust and ejection device according to claim 2, characterized in that, The pressure feedback unit is a pressure sensor that detects the gas pressure inside the air cushion. The pressure feedback unit, position encoder, quick-release solenoid valve, the clutch power supply of the crankshaft drive motor of the crankshaft connecting rod mechanism, and the bottom dead center switch of each mold top block are all electrically connected to the PLC control unit.

4. The working method of the press air cushion rapid exhaust and ejection device according to claim 3, characterized in that, Includes the following steps: (1) The PLC control unit of the press controls the press to enter the preparation for punching, so that the slide of the press is at the top dead center position, and the crankshaft of the crankshaft connecting rod mechanism that drives the slide of the press is at the 0 degree position. (2) The PLC control unit of the press controls the slide of the machine tool to press down. At this time, the fast exhaust solenoid valve is de-energized and opens. The air cushion exhausts the air into the air tank. At the same time, the position encoder collects the crankshaft angle signal in real time. (3) The robot places the workpiece to be stamped onto the lower die. The robot is connected to the PLC control unit of the press. The robot then turns on the two-hand button switch of the press to trigger the start signal of the press. (4) The PLC control unit of the press controls the slide of the press to descend and press the workpiece. At the same time, it detects the crankshaft angle signal collected in real time by the position encoder in step (2). When the crankshaft rotation angle of the press is in the secondary exhaust position, the upper die has pressed the workpiece. The bottom dead point switch of each die block receives the signal. At the same time, the bottom dead point switch of each die block is compared with the real-time signal of the position encoder. When the real-time signal of the position encoder is also in the secondary exhaust position, it feeds back to the PLC control unit and disconnects the clutch power supply. (5) After the clutch power is de-energized, the slider continues to descend towards the bottom dead center under the action of inertia. Before the slider reaches the bottom dead center, the clutch power is de-energized and waits for 1-5 seconds. The PLC control unit of the press is equipped with a touch screen that can control the waiting time of the clutch power de-energized. After the quick exhaust solenoid valve is opened, the gas in the lower chamber of the air cushion is discharged. The air pressure of the first piston rod of the nitrogen cylinder is removed. The first piston rod of the nitrogen cylinder moves downward and presses down the upper piston. Before the slider reaches the bottom dead center, the first piston rod of the nitrogen cylinder presses out the residual gas in the upper chamber and middle chamber of the air cushion. After the air cushion is completely vented, the pressure feedback unit detects the corresponding pressure signal and feeds it back to the PLC control unit. The PLC control unit automatically restores the running signal, the clutch power is energized, and the slider continues to run until it reaches the top dead center. After the slider leaves the bottom dead center, the quick exhaust solenoid valve is energized, and the air tank fills the air cushion. Before the slider reaches the top dead center, the upper piston pushes the top block up, and the top rod pushes out the workpiece. The ejection is completed. (6) The crankshaft of the press is at 0 degrees at this time. When the next workpiece needs to be stamped, the steps (2)-(5) are repeated. When the workpiece does not need to be stamped, the crankshaft of the press remains stationary and is in standby mode.

5. The working method of the press air cushion rapid exhaust and ejection device according to claim 4, characterized in that, The secondary exhaust position of the press crankshaft is when the crankshaft rotates at an angle of 165-170 degrees.

6. The working method of the press air cushion rapid exhaust and ejection device according to claim 5, characterized in that, When the bottom dead center switch of each mold top block receives a signal, if the real-time signal of the position encoder is not in the secondary venting position, the PLC control unit of the press will issue an alarm signal and will not perform subsequent stamping; when the real-time signal of the position encoder is adjusted to the secondary venting position, the press's two-hand button switch needs to be turned on again to trigger the press start signal before stamping can continue.

7. The working method of the press air cushion rapid exhaust and ejection device according to any one of claims 4-6, characterized in that, The press body is equipped with a key switch and an action indicator light for controlling the operation of the air cushion.

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