JPH04201228A - Pin breaking detector for extruder - Google Patents

Abstract

PURPOSE:To detect the breaking of a stirring pin prior to the separation and come-off of the pin when the pin is broken, and to form a detecting means imply by providing the stirring pin with the detecting means for detecting the relative displacement of an external cylinder with a hole section and a detecting shaft, in which a front end is held by the inner end section of the external cylinder and relative displacement is generated between the external cylinder and the detecting shaft by the bending of a projecting section. CONSTITUTION:When the projecting section 13 of a stirring pin 6 is bent and deformed, the shaft core of the hole section 9 of an external cylinder 10 is curved, and shaft core length is elongated. A detecting lever 11a held by the inner end of the hole section 9 is moved toward a hole 4. The actuating lever 11a, an inner end of which is abutted against the detecting lever 11, is extruded to the hole 4 side by the pressure of air interposed to an air hole 27, relative displacement is generated between the external cylinder 10 and a detecting shaft 11 and a valve body 15 is opened, and air in the air hole 27 is discharged to the outside air through an introducing hole 41 by the opening of the valve body 15. Air pressure in an air pipe 45 communicating with the air hole 27 is lowered, the lowering of air pressure is sensed by the pressure sensor 16 of a detecting means 7, and a motor M is stopped through a control tool N.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pin that is attached to a pin-type extruder for extruding plastic materials such as rubber and resin, and that works together with a screw to knead the rubber and other plastic materials. , relates to a pin break detection device for an extruder that can detect breakage before the pin falls off due to breakage, thereby increasing the safety of the device.

[Conventional technology]

For example, as a device for kneading a plastic material such as rubber and sending the kneaded plastic material to the next process, an extrusion device is known that rotates a screw in a cylindrical body to knead it. In addition, among such extrusion devices, there is also one in which a large number of pins b are implanted inside a cylinder a, as shown in FIG. 2, for example, in order to improve the ability to stir the rubber material.

[Problem to be solved by the invention]

By protruding the pin b in this manner, the kneading ability is increased, but the pin b may be damaged due to pressure from the rubber material fed by the screw C or contamination of foreign matter.

In addition, in such a device, if one pin breaks, that pin will be carried along with the rubber and break the pins located at the rear one after another, resulting in a major accident that may cause the device to stop operating. It often becomes.

In order to solve one part of these problems, a device for detecting breakage of a pin has been proposed, for example, in Japanese Patent Application Laid-Open No. 59-19123, but in this device, the pin is formed hollow and there is a hole inside. An electrical conductor made of carbon paper is inserted through an insulator, and is designed to detect changes in the resistance value of the electrical conductor when the pin is broken. Therefore, in the proposed method, bending of the pin is detected by replacing the deformation of the pin with the resistance value, and since changes in the resistance value are read with high precision, the device becomes complicated and expensive.

In addition, if the pin is in a broken state where the crack expands temporarily due to fatigue failure, etc., and the pin does not deform until it is about to break,
The detection time may be delayed and the pin may separate and break.
There is a need for an apparatus that can detect pin breakage at an early stage and that can be provided economically.

The present invention includes a stirring pin that includes an outer cylinder, a detection shaft that is fitted into a hole of the outer cylinder and whose tip is held at the inner end of the outer cylinder, and a detection means that detects relative movement between the detection shaft and the outer cylinder. It is an object of the present invention to provide a pin breakage detection device for an extruder which can detect breakage of a stirring pin before the pin separates and falls off, and which can be easily formed.

[Means to solve the problem]

The present invention provides a pin-type rubber extruder in which a plurality of stirring pins protruding inward from the circumferential surface of the hole are implanted in a base cylinder having a hole through which a screw for extruding a plastic material passes. In the pin breakage detection device, the stirring pin includes an outer cylinder fixed to the base cylinder, protruding inward from the circumferential surface of the hole, and having a hole, and an outer cylinder that is fitted into the hole and has a tip outside. and a detection means for detecting the relative displacement of a detection shaft that is held at the inner end of the cylinder and causes a relative displacement between the outer cylinder and the outer cylinder due to bending of the protruding part of the outer cylinder. This is a pin breakage detection device.

[Effect]

Since the stirring pin includes the outer cylinder and the detection shaft configured as described above, the bending of the protrusion of the outer cylinder causes a relative displacement between the detection shaft and the outer cylinder. This displacement occurs during bending deformation before the outer cylinder breaks and separates, and the detection means can be activated by this displacement.

Therefore, the detection means can detect an abnormality prior to separation due to breakage of the inner end of the outer cylinder, so accidents can be discovered early and the safety of the device can be improved.

The detection means can be of various structures as long as it can detect the relative positional deviation between the outer cylinder and the detection shaft.For example, electric detection using an electric sensor that turns on and off electrically depending on relative displacement. It is possible to use a pressure detection means, etc., which changes the air pressure by a means or relative displacement and detects the change with a pressure sensor. In particular, the pressure detection means can control a plurality of stirring pins in a simple manner and can be suitably employed in a pin rubber extruder.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings, taking as an example the case where the plastic material is rubber.

In the figure, a pin breakage detection device 1 for an extruder is attached to a pin-type rubber extruder K, and is attached to a base cylinder 5 having a hole 4 through which a screw 3 for extruding rubber passes.
A plurality of stirring pins 6- are implanted to protrude inward from A, and the stirring pins 6 are provided with detection means 7 for detecting bending.

The base cylinder 5 is a straight cylinder with both ends open, and the negative end surrounds the output shaft of the reducer R and is fixed to the side wall of the reducer R. Further, a motor M is connected to the input shaft of the reducer R via a transmission mechanism.

In this embodiment, the base cylinder 5 is divided into three parts in the axial direction, and includes a first cylinder 5A, a second cylinder 5B, and a third cylinder 5C from the reducer side. 5A, 5B.

5C is a flange 21- projecting outward from the opposing end faces.
They are firmly fixed together by bolting them together.

A hopper 22 for charging the rubber material is provided on the upper surface of the first cylindrical body 5A, and a cap body 24 having a discharge hole 23 in the center is attached to the tip of the third cylindrical body 5C.

In addition, a plurality of pin holes 26- are bored through the inside and outside of the base cylinder 5 at equal positions in the circumferential direction in the second and third cylinders 5B and 5C, and the pin holes 26 are They are provided in multiple stages in the axial direction at approximately equal intervals.

The pin hole 26 is a hole that penetrates the peripheral wall of the base cylinder as shown in FIG. It consists of a hole 26a. Further, a screw hole portion 26c having a female thread carved on the circumferential surface is provided on the outside of the large hole portion 26a.

The screw 3 has a straight rod-shaped base portion having one end axially coupled to the output shaft of the reducer R, disposed within the hole 4 of the base tube 5 with a gap g, and having a length substantially equal to the length of the base tube. A screw blade 3b whose radially outer side protrudes near the wall surface of the inner hole 5 of the base cylinder is attached to the circumferential surface of the screw blade 3a.

The stirring pin 6 is inserted into the pin hole 26 of the base cylinder 5, and the outer cylinder 1 has a hole 9 that is transparently provided approximately coaxially with the pin hole 26.
0, the detection shaft 11 fitted into the hole 9, and the detection means 7
and.

In this embodiment, the outer cylinder 10 includes a base portion that is fitted into the large hole portion 26a, and a small diameter portion that fits into the small hole portion 26b and has a protrusion portion 13 that projects from the circumferential surface 4A of the hole 4. an inner member 10a, a nut member 10b screwed into the screw hole 26c, and an outer member sandwiched between the inner member 10a1 and the nut member 10b and extending outward through a hole passing through the center of the nut member 10b. It consists of a material 10c and a tubular air supply member 10d which is screwed to the outer end of the outer member 10c so that its length can be adjusted and has an air hole 27 in the center.

Therefore, the outer cylinder 10 is fixed to the base cylinder 5, and the protrusion 13 protrudes inward from the circumferential surface 4A of the hole 4.

The internal member 10a including the protrusion 13 is preferably formed by hardening, using a strong steel such as nickel chrome steel, which has both strength and toughness.

The hole portion 9 also includes an enlarged hole portion 31 located inside the inner hole 30 and at the open end facing the cavity 4 in the protruding portion 13 and having an inner diameter larger than that of the inner hole 30 . Also, the hole 9 is
The outer member 10c has an outer hole 32 that passes through the outer member 10c and has a larger diameter than the inner hole 30 in this embodiment.

The detection shaft 11 fits into the outer hole 32 and is connected to the outer member 1.
an operating rod 11a that can move relative to 0c; and the internal member 10.
The inner hole 3 is inserted into the locking portion 35 that fits into the enlarged hole portion 31 of a.
The detection rod 11b is inserted into the operating rod 11a and has an extended base rod 36 whose outer end abuts the inner end of the operating rod 11a. Note that the detection rod 11b is movably inserted into the inner hole 30. Further, the locking portion 35 is press-fitted into the enlarged hole portion 31 so as to be immovable.

The operating rod 11a is slidably inserted into the outer hole 32 of the external member 10c, has a cone-shaped outer end surface, and closes the air hole 27 of the air supply member 10d at its inner opening. You can.

By moving the operating rod 11a back and forth in the axial direction, the outer end surface of the operating rod 11a can come into contact with and away from the inner opening of the air hole 27. Therefore, the outer end surface of the operating rod 11a is the valve body 39.
Further, the inner opening of the air supply member 10d forms a valve portion 15 that serves as a valve seat 40, respectively. The position of the valve seat 40 can be adjusted by screwing the outer member 10c and the air supply member 10d back and forth, and the screwing is fixed using a nut piece 37. Note that when the outer cylinder 10 is in a normal state without deformation, the valve portion 15 is in a closed state.

Further, the outer member 10c is provided with a conductive hole 41 through which the outside air can be communicated through the outer hole 32 at an inner position where the air supply member 10d is screwed.

The air hole 27 of the air supply member 10d communicates with the air source H.

The air source H is, for example, a compressor, and the compressed air from the air source H passes through an air filter 51, a pressure reducing valve 52, and a throttle valve 53, and then a pressure detector 16 that detects the air pressure in the flow path.
reach. Further, the air passing through the pressure sensor 16 is guided to the air hole 27- of each stirring pin 6 by the branch portion 55.

The pressure sensor 16 transmits the detected air pressure to the motor M.
The pressure is transmitted to a control device N attached to the pressure sensor 16, and the control device N can turn on and off the motor M according to the signal from the pressure sensor 16.

Therefore, in this embodiment, the detection means 7 is formed by the valve portion 15 formed by the outer cylinder 10 and the detection shaft 11, and the pressure detector 16.

Note that the screw blades 3b are notched at the portions that abut against the stirring pins 6 when rotated to prevent mutual interference.

Therefore, by driving the motor M, the screw 3 is rotated. The rubber material introduced from the hopper 22 enters the gap g of the cavity 4. The rubber material present in the gap g is dragged by the screw 3 due to mutual friction with the screw 3, and is pushed forward, collides with the stirring pin 6, and is deformed and crushed.

The rubber material is crushed from the hopper 22 to the discharge port 2.
3, the rubber material is kneaded and discharged from the discharge port 23.

Therefore, when the rubber material is kneaded, a large bending moment generated by the pressing of the rubber material acts on the stirring pin 6. In addition, during rubber kneading, vibrations occur due to the rotation of the screw 3 and the screwing of the rubber material while engaging with the stirring pin 6.

In particular, the stirring pins 6, which are arranged in several stages on the upstream side starting from the hopper 22, tend to receive a large bending moment and generate large vibrations.

When the stirring pin 6 is in a normal state with no deformation of the protrusion 13, the stirring pin 6 is inserted into the outer cylinder 1 as shown in FIGS. 4(a) and 4(b).
The axis of the hole 9 of No. 0 is straight and straight, and therefore the detection shaft 11 is also kept straight. In this state, the valve part 15 blocks the flow of air, so that the pressure of the air in the air hole 27 is maintained constant, and the pressure detector 54 sends a drive signal to the motor M. put out.

However, if bending deformation occurs in the protrusion 13, the axis of the hole 9 of the outer cylinder 10 will curve and the axis length will increase, as shown in FIG. Therefore, the detector 11a held at the inner end of the hole 9 moves toward the hole 4.

As a result, the operating rod 11a abuts the detector 11b at its inner end.
is pushed out toward the inner hole 4 side by the pressure of the air present in the air hole 27, a relative displacement occurs between the outer cylinder 10 and the detection shaft 11, and the valve body 15 is opened.
The air passes through the guide hole 41 and is discharged to the outside air.

Therefore, the air pressure in the air pipe 45 communicating with the air hole 27 decreases, and the pressure detector 16 detects this decrease in air pressure, and the motor M is stopped via the controller N.

The pin breakage detection device according to the present invention is provided on all the stirring pins implanted in the base tube 5, and is also provided at several rows of positions starting from the popper 21 on the upstream side where the greatest force is applied. It may be provided only for the stirring pin.

Further, in the present invention, it is also possible to employ an electric type detection means using, for example, a proximity switch for detecting the relative displacement between the outer cylinder and the detection shaft. The detection means can detect pin breakage of a large number of stirring pins at once, is easy to configure, and can be provided at a low price.

In order to improve the detection accuracy, it is also possible to provide a plurality of pressure detectors in parallel and to detect the stirring pins in groups. In this case, broken pins can be easily detected and the operating efficiency of the extruder can be improved.

The extrusion contact layer pin break detection device of the present invention can be applied to a pin-type extruder that kneads and extrudes plastic materials such as resin materials in addition to rubber.

〔Effect of the invention〕

As mentioned above, the pin breakage detection device for an extruder of the present invention is characterized in that the stirring pin is equipped with a detection means for detecting the relative displacement between the outer cylinder and the detection shaft. It can be detected before it falls off, preventing damage to the extruder and increasing the reliability of the extruder. Moreover, since the device can be easily formed, it can be provided economically.

[Brief explanation of the drawing]

FIG. 1 is a front view schematically showing an extruder using the pin breakage detection device of the present invention, FIG. 2 is an enlarged sectional view of the main parts thereof, and FIG. 3 is a sectional view taken along the line X-X. FIG. 4(a) is a sectional view showing the stirring pin, FIG. 4(b) is an enlarged sectional view showing the valve part thereof, and FIG. 5 is a sectional view showing the broken state.
FIG. 6 is a piping diagram showing the air path. 3-screw, 4...--hole, 4A-,-
Peripheral surface, 5 - base cylinder, 6 - stirring pin, 7 - detection means, 9 - hole, 10 - outer cylinder, 11 - 1 - detection shaft, 13 - protrusion. Patent applicant Nakata Zoki Co., Ltd. Agent Patent attorney Tadashi Naemura Fig. 1 Fig. 4 (a) Fig. 4 (b)] 5 1a Fig. 5 Fig. 6/M

Claims (1)

[Claims] 1. A pin breakage detection device for an extruder, in which a plurality of stirring pins protruding inward from the circumferential surface of the hole are implanted in a base cylinder having a hole through which a screw for extruding a plastic material passes. The stirring pin includes an outer cylinder fixed to the base cylinder, protruding inward from the circumferential surface of the hole, and having a hole, and the stirring pin is fitted into the hole and has a tip at an inner end of the outer cylinder. A pin breakage detection device for an extruder, comprising: a detection means for detecting the relative displacement of a detection shaft that causes a relative displacement between the outer cylinder and the outer cylinder due to the bending of the protrusion of the outer cylinder when held.