JPH0350097Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is a cylinder drive device in a screw supply device, etc., more specifically, a cylinder drive device in a screw supply device, etc., which supplies and discharges compressed air to both ends of the cylinder. The present invention relates to a cylinder driving device which operates a piston therein and controls switching between supply and discharge of compressed air by reducing the pressure on the exhaust side of the cylinder when the piston stops.

(Prior art and its problems) For example, in a screw supply device of a type in which a raking means appears and retracts in a screw storage hopper and the raked screws are fed onto a chute rail, the raking means is operated. A cylinder device is provided, and is configured to operate the scraping means in conjunction with the operation of the piston.

In many cases, the cylinders mentioned above are driven by supplying and exhausting compressed air.
As shown in Japanese Patent No. 18437, a method using a solenoid valve operated by an electrical signal is known. A one-way valve and a throttle valve are arranged in parallel in each air passage connected to both ends of the cylinder, and by restricting the discharge of compressed air in the cylinder on the exhaust side, the operating speed of the piston is reduced to a slow speed. It has become

By the way, the timing of the electrical signal that switches the solenoid is generally based on (a) a signal supplied at fixed intervals by a timer, and (b) a detection signal from a detector placed at the end of the piston's stroke. However, according to method (a) above, if the load on the scraping means changes depending on the amount of screws in the hopper, or if the pressure of the compressed air that drives the cylinder changes, etc. If the stroke time of the piston changes, the changeover occurs before the scraping means reaches the top dead center, resulting in a situation in which screws cannot be fed out. Furthermore, according to method (b) above, if the raking means is locked and stopped due to clogging of screws in the hopper, compressed air is supplied to the cylinder because switching is not performed. becomes inoperable if it is still supplied. Therefore, a cylinder drive control device that is different from the above-mentioned switching system has been desired.

(Technical issues of the invention) The present invention was developed in view of the above circumstances, and actively utilizes the phenomenon that the pressure on the exhaust side of the cylinder is maintained constant while the piston is operating. This allows the piston to operate between the top dead center and the bottom dead center even if the air pressure of the compressed air supplied to the cylinder or the load on the piston changes. It is an object of the present invention to propose a driving device for a cylinder in a screw supply device, etc., which can immediately switch the direction of operation and eliminate a blockage when the cylinder stops operating in the middle of a stroke.

(Means for Solving the Problems) In order to solve the above problems, the cylinder drive device in the screw supply device, etc. according to the present invention supplies compressed air to both ends of the cylinder and exhausts the air inside the cylinder. In a screw supply device that operates a piston housed in a cylinder and links the operation of the piston with the scraping operation of a scraping means such as a screw, each passage means connected to the operating end portions at both ends of the cylinder is connected to the Selectively connected to the compressed air supply source and the atmosphere via a switching valve that is switched and operated by compressed air supplied to both working ends and alternately connects each of the passage means to the compressed air source and the exhaust port. , The exhaust port of the switching valve communicating with the atmosphere is provided with a restriction means for restricting the discharge of the compressed air in each of the passage means to maintain the pressure in the passage means connected to the exhaust side during operation of the cylinder. A pilot valve for switching and operating the switching valve is provided in two passage means communicating between each operating end of the cylinder and each operating end of the switching valve, and the switching is performed via the pilot valve. The operating ends on both ends of the valve are selectively connected to a compressed air supply source and the atmosphere, and the operating end of one of the pilot valves is connected to the compressed air supply when the piston operates in the direction of scraping up screws, etc. The operating end of the switching valve is compressed through the one pilot valve by maintaining the compressed air pressure in the passage means. A sub-pilot valve is provided in the passage means connected to the air supply source and connected to the other pilot valve and the operating end of the cylinder that becomes the exhaust side when the piston operates in the direction of scraping up screws, etc. , the other pilot valve is connected to a compressed air supply source and the atmosphere through a sub-pilot valve operated by compressed air from the working end of the cylinder, which is the exhaust side of the cylinder; The operating end of the switching valve is connected to the compressed air supply source through the sub-pilot valve and the other pilot valve by maintaining the compressed air pressure.

(Operations and effects of the invention) According to the above configuration, the switching operation of the switching valve is controlled by the pilot valve and the sub-pilot valve, but the air pressure in the passage means connected to the operating end of the cylinder is maintained. Since the working end of the switching valve is connected to the compressed air supply source through the pilot valve and sub-pilot valve, the pilot valve and sub-pilot valve are activated when the piston in the cylinder stops. It will be done. Therefore, not only when the piston reaches the top or bottom dead center, but also when the operating stroke time of the piston changes due to fluctuations in compressed air pressure, or when the piston becomes locked due to clogging, etc. can also perform predetermined operations.

Also, when the rake plate is operating in the rake direction, it stops for a very short time due to instantaneous jamming of screws, etc., and then the rake plate starts moving again. Since the air pressure fluctuates, the sub-pilot valve also operates by switching in small steps based on this. However, as the compressed air that had been supplied to the pilot valve is exhausted from the sub-pilot valve when the sub-pilot valve is switched, the pressure is reduced to a level sufficient for the pilot valve to switch. However, a time lag occurs. Therefore, if the scraping plate starts to move again and the sub-pilot valve is re-operated before the pressure is sufficiently reduced, the pilot valve cannot switch and operate, so the current state is maintained and the operation of the switch-over valve does not change.
In this way, by interposing the sub-pilot valve between the cylinder and the pilot valve, even if the piston stops for a short period of time and then starts moving again, a detailed switching operation will not be performed accordingly. , it is possible to maintain good raking efficiency.

Furthermore, since the exhaust port of the switching valve that communicates with the atmosphere is equipped with a throttle means, the compressed air can be exhausted quickly, and the piston operates at a slow speed, making it possible to reliably scrape up screws. can.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In the figure, symbol A indicates a screw supply device. This screw supply device A is provided with a scraping plate 2 (raking means) retractable from a guide groove 1a provided in a screw storage hopper 1, and the scraping plate 2
Screw up the screws with their heads aligned, and then move these screws from the hopper 1 to the screw guide chute 3.
It is intended to provide guidance and guidance.

The raking plate 2 is made up of two fan-shaped plates 2.
a and 2b are arranged to face each other in parallel with a screw guide gap larger than the screw shaft and smaller than the head, and the base is pivoted to a support member 4 provided on the machine base of the screw supply device A. , the edge on the arcuate side is configured to move along a clogging prevention wall 5 provided at the center bottom of the hopper 1.

The screw guide chute 3 is connected to the above-mentioned scraping plate 2.
Continuously provided in the screw guide gap inside.

A protruding member 7 is fixed to the swinging shaft 6 of the scraping plate 2 or its base, and the distal end of the driving rod 9 of the driving cylinder 8 is pivotally attached to the distal end of the protruding member 7.

In the above configuration, by driving the cylinder 8, the drive rod 9 is operated in the vertical direction, and the scraping plate 2 is swung together with the protruding member 7. The oscillated scraping plate 2 moves into and out of the guide groove 1a of the hopper 1, scrapes up the screws therein, and guides them to the screw guide chute 3.

By the way, the driving device for the cylinder 8 is configured as follows. This will be explained with reference to FIG.

First, the cylinder 8 accommodates a piston 10 that is integrally connected to a drive rod 9, and an air passage 1 that connects both ends of the cylinder 8 with a compressed air supply source 12.
3, compressed air is supplied to both ends of the cylinder 8.
A switching valve 14 for exhausting the air is provided. A throttle means 11 for restricting the discharge of compressed air within the cylinder 8 is disposed at the exhaust port of the switching valve 14. A one-way valve 15a, 15b and a speed control valve 16 are arranged in parallel in each air passage 13a, 13b connecting both ends of the cylinder 8 and the switching valve 14, respectively.

A first passage means 1 is provided at the upper end of the cylinder 8.
7 is connected, and the first passage means 17 connects one working end 14a of the switching valve 14 to the compressed air supply source 1.
2 and to the working end of a pilot valve 19 which is selectively connected to the atmosphere. A second passage means 18 connected to the lower end of the cylinder 8 is connected to a pilot valve 20.
It is configured to be selectively connected to the compressed air supply source 12 and the atmosphere by a sub-pilot valve 20 which selectively connects the working end of the compressed air source 12 to the atmosphere.

Here, the operating mode of the drive device for the cylinder 8 will be explained based on FIGS. 2 to 5.

First, the compressed air supply source 1 is
2 is supplied from the upper end of the cylinder 8 in FIG. As a result, compressed air from the compressed air supply source 12 is supplied from the air passage 13a to the upper end of the cylinder 8, pushing down the piston 10 and operating the raking plate 2 in the raking direction.

At the same time, the compressed air is supplied from the first passage means 17 to the operating end of the pilot valve 19, which operates the pilot valve 19, which connects one operating end 14a of the switching valve 14 to the compressed air supply source 12. The compressed air presses one end of a valve stem (not shown).

When the piston 10 operates, compressed air is discharged from the lower end of the cylinder 8 in the figure through the air passage 13b and from the exhaust port 22 of the switching valve 14. Since the exhaust port 22 is provided with the throttle means 11, the discharge of the compressed air from the cylinder 8 is restricted, and therefore the operating speed of the piston 10 in the direction of scraping up the scraping plate 2 is controlled to a slow speed.

At the same time, the compressed air discharged from the cylinder 8 is maintained at a high pressure within the second passage means 18 as shown by the thick dotted line, and the exhaust pressure is transferred from the second passage means 18 to the sub-pilot valve 21. The actuation of this sub-pilot valve 21 causes the actuation end of the pilot valve 20 to communicate with the compressed air supply source 12, thereby actuating the pilot valve 20 and causing the other side of the switching valve 14 to communicate with the compressed air supply source 12. The working end 14b of the valve is connected to the compressed air supply source 12 and presses the other end of its valve stem (not shown). As a result, the valve rod receives the same pressure from both ends at the same time and is thus held in the same position.

Then, when the piston 10 reaches the bottom dead center, there is no more air forced into the second passage means 18 by the piston 10 and the second passage means 18
As a result, the exhaust pressure within the second passage means 18 is exhausted from the exhaust port 22 of the switching valve 14, thereby reducing the exhaust pressure within the second passage means 18. Therefore, as shown in FIG. 3, the sub-pilot valve 21 is operated to return, and as a result of this return, the operating end of the pilot valve 20 is communicated with the atmosphere through the exhaust port 23, and the pilot valve 20 is
Further, due to the return of the pilot valve 20, the operating end 14b of the switching valve 14 is connected to the atmosphere through the exhaust port 24. As a result, the balance of air pressure acting on both operating ends 14a, 14b of the switching valve 14 is lost, and the switching valve 14 is switched as shown in the figure.

Due to the switching operation of the switching valve 14, the compressed air from the compressed air supply source 12 is now diverted to the air passage 1.
3b to the lower end of the cylinder 8, and the compressed air from the upper end of the cylinder 8 is operated to be exhausted to the atmosphere through the air passage 13a and the exhaust port 25. As a result, compressed air from the compressed air supply source 12 is supplied to the lower end of the cylinder 8 to push up the piston 10, as shown in FIG. At the same time, it is supplied via the second passage means 18 to the operating end of the sub-pilot valve 21, thereby actuating the sub-pilot valve 21 again. The actuation of this sub-pilot valve 21 connects the operating end of the pilot valve 20 and the compressed air supply source 12, and the pilot valve 20 is actuated by the compressed air, and the switching valve 1
The working end 14b of 4 is connected to the compressed air supply source 12.

On the other hand, the air discharged from the upper end of the cylinder 8 based on the operation of the piston 10 is discharged from the air passage 1.
3a and is exhausted from the exhaust port 25 of the switching valve 14. Throttle valve 11 provided in exhaust port 25
The exhaust pressure maintained at a high pressure as shown by the thick dotted line is supplied from the first passage means 17 to the operating end of the pilot valve 19.
9 is maintained in the above operating state, and compressed air from the compressed air supply source 12 is supplied to one operating end 14a of the switching valve 14 via the pilot valve 19. As a result, the air pressures acting on both operating ends of the switching valve 14 are balanced.

Then, when the piston 10 reaches the top dead center,
As shown in FIG. 5, as the piston 10 stops discharging air and the air inside the air passage 13a is discharged from the exhaust port 25 of the switching valve 14,
The pressure in the first passage means 17 connected to the operating end of the pilot valve 19 is reduced, and the pilot valve 19 operates as shown in the figure, whereby one operating end 14a of the switching valve 14 is opened to exhaust air. It is connected to the atmosphere via port 26. As a result, the switching valve 14
The pressure balance between the two operating ends 14a and 14b is lost, and the switching valve 14 is switched again as shown in FIG.

In this way, the switching operation of the switching valve 14 is controlled by the pilot valves 19, 20 and the sub-pilot valve 21. Therefore, not only when the piston 10 reaches the top or bottom dead center, but also when the driving air pressure fluctuates and the operating stroke 20 hours of the piston 10 changes, the screws become clogged and become locked. Predetermined operations can be performed even when such situations occur.

Furthermore, when the raking plate 2 is operating in the raking direction, it stops for a very short time due to momentary clogging of screws, etc., and then the raking plate 2 starts moving again. Passage means 1
Since the exhaust pressure at 8 fluctuates, the sub-pilot valve 21 also performs fine switching operations based on this, and accordingly, the pilot valve 2
0 will operate in the same manner, and the switching valve 14 will be switched and operated many times within a short period of time.

However, due to the switching operation of the sub-pilot valve 21, the compressed air that had been supplied to the pilot valve 20 is exhausted from the sub-pilot valve 21.
There is a slight time lag until the pressure is reduced enough for the pilot valve 20 to operate. Therefore, if the scraping plate 2 starts to move again and the sub-pilot valve 21 is re-operated before the pressure is sufficiently reduced, the pilot valve 20 will not be able to switch and operate, so the same state will be maintained and the switching valve 14 will not operate. remains unchanged.

In this way, by interposing the sub-pilot valve 21 between the cylinder 8 and the pilot valve 20, even if the piston 10 stops for a short period of time and starts moving again, fine switching operations can be performed accordingly. Therefore, it is possible to maintain good raking efficiency.

Note that a chamber of an appropriate size may be provided between the sub-pilot valve 21 and the pilot valve 20 of the second passage means 18, or the sub-pilot valve 21 may be
By narrowing the exhaust port, the rapid flow of compressed air can be suppressed, so the above effect becomes even more pronounced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of the screw supply device according to the present invention, and FIGS. 2 to 5 are explanations of the air control circuit of the cylinder drive device in the screw supply device and its operating mode. It is a diagram. Symbol A...Screw supply device, 2...Screwing plate, 3...Screw guide chute, 8...Cylinder, 10...Piston, 13...Air passage, 14
...Switching valve, 11... Throttle means, 17... First
passage means, 18...second passage means, 19,2
0...Pilot valve, 21...Sub pilot valve.

Claims (1)

[Claims for Utility Model Registration] By supplying and exhausting compressed air to both ends of the cylinder, a piston housed in the cylinder is operated, and this piston operation and the scraping operation of the scraping means such as screws, etc. In the screw supply device, each passage means connected to both working ends of the cylinder is switched and operated by compressed air supplied to both working ends, and the passage means are alternately compressed. The compressed air supply source is selectively connected to the atmosphere via a switching valve that is selectively connected to the air source and the exhaust port, and the exhaust port of the switching valve that communicates with the atmosphere restricts the discharge of the compressed air in each of the passage means. restricting means is arranged to maintain pressure in the passage means connected to the exhaust side during operation of the cylinder, and communicates each working end of said cylinder with each working end of said switching valve. A pilot valve for switching and operating the switching valve is provided in each of the two passage means, and each operating end of the switching valve is selectively connected to a compressed air supply source and the atmosphere via the pilot valve, The working end of the pilot valve is connected to the passage means connected to the working end of the cylinder which becomes the compressed air supply side when the piston operates in the direction of scraping up screws, etc. By maintaining the compressed air pressure, the operating end of the switching valve is connected to the compressed air supply source through the one pilot valve, and the piston is moved in the direction of scraping up the screws, etc. with the other pilot valve. A sub-pilot valve is provided in the passage means connected to the operating end of the cylinder which becomes the exhaust side when the cylinder is operated, and the other pilot valve is operated by compressed air from the operating end which becomes the exhaust side of the cylinder. connecting the compressed air supply to the atmosphere through a sub-pilot valve which is actuated and switching between the sub-pilot valve and the other pilot valve by maintaining compressed air pressure in the passage means; A driving device for a cylinder in a screw supply device, etc., characterized in that an operating end of a valve is connected to a compressed air supply source.