JPH04320807A - Method of supplying material in rubber material preparing apparatus - Google Patents

Abstract

PURPOSE:To provide a method of supplying materials in a rubber material apparatus capable of pushing out the mass of a correct weight rubber material without causing any scatter in the weight of the mass of a rubber material. CONSTITUTION:While a supplying screw 7 is rotated at a constant speed, a rubber material is placed into the inner part of a material supplying cylinder, the rubber material is pushed into the inner part of a supplying head 4 while being kneaded by means of a screw 7. The rubber material supplied in the supplying head 1 passes through a material passage 1b and comes into the inner part of a metering cylinder 3 to thereby gradually push up a free state metering plunger 5 with the result that the rubber material is filled in the inner part of the metering cylinder 3. Next, after a pressure relief plunger 12 is sucked out of a pressure relief part 1c and pressure in the inner part of the metering cylinder 3 is dropped once, the metering plunger 5 is pushed into the metering cylinder 3 so that the rubber material is pushed out of an extruding part 1a.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material feeding method in a rubber material preparation apparatus for preparing rubber material for molding (rubber material mass weighed to a predetermined weight) for use in compression molding or the like.

0002

[Prior Art] Conventionally, when preparing a rubber material for molding used in compression molding, etc., for example,
Rubber material, that is, a lump of rubber material weighed to a predetermined weight, was prepared using the apparatus and method shown in the publication.

That is, as shown in FIG. 4A, first, a tape-shaped rubber dough is introduced into the material supply cylinder 20 through its input port, and the screw plunger 21 is rotated. At this time, the screw plunger 21 moves backward in the right direction in FIG. 4a due to back pressure, and the material supply cylinder 20
The rubber material is introduced into the tip of the rubber material while being kneaded.

When the screw plunger 21 is retracted to a predetermined position, the switching valve 22 in the supply head 23 is switched as shown in FIG. 4b, and the push cylinder 24 moves the screw plunger 21 forward to the left in FIG. 4b. As a result, the rubber material flows into the metering cylinder 25 in the supply head 23 through the switching valve 22 while pushing up the metering plunger 26, and the metering plunger 26 stops when it hits the stopper 27, and a certain amount of the rubber material flows into the metering cylinder 25. 25 is filled.

Then, the switching valve 22 is switched as shown in FIG. 4c, and the metering plunger 26 is pushed down by a certain stroke by a hydraulic cylinder (not shown), thereby extruding the rubber material from the extrusion port of the supply head 23.
Next, as shown in FIG. 4d, the measured rubber material mass is cut by the cutting blade 28 and supplied.

[0006]

[Problems to be Solved by the Invention] However, in the conventional method, as described above, the screw plunger 21 is pushed in by the pushing cylinder 24, and the rubber material in the material supply cylinder 20 is measured while applying high pressure to the rubber material. Because the rubber material flows into the cylinder 25, a local density difference occurs in the rubber material in the material supply cylinder 20 and/or the lightweight cylinder 25, and as a result, the compression ratio of the rubber material varies each time the rubber material is supplied. There was a problem with variations in weight.

That is, the two graphs a and b in FIG. 5 show the change in the weight of the rubber material lump with respect to the number of extrusions of the rubber material when extruded by the conventional material supply method. As can be seen from b, the weight of the rubber material mass varied by about 0.2 g each time the rubber material mass was extruded.

The present invention has been made to solve the above-mentioned problems, and provides a rubber material preparation device that can extrude rubber material lumps of accurate weight without causing variations in the weight of the rubber material lumps. The purpose is to provide a material supply method.

[0009]

[Means for Solving the Problems] To this end, the material supply method of the rubber material preparation device of the present invention includes filling a measuring cylinder with the rubber material introduced into a material supply cylinder through a material passage in a supply head; In a material supply method of a rubber material preparation device that extrudes and supplies a certain amount of rubber material from an extrusion part of a supply head by pushing a metering plunger into a metering cylinder, a metering plunger is formed to communicate with a material passage in the supply head. A pressure relief plunger is inserted into the pressure relief chamber, and the supply screw in the material supply cylinder is rotated.
Fill the measuring cylinder while pushing the rubber material into the supply head, then pull out the pressure relief plunger from the pressure relief chamber to lower the pressure inside the measuring cylinder, then push the measuring plunger into the measuring cylinder and supply. The rubber material is extruded from the extrusion part of the head.

0010

[Operation] Rubber material is fed into the material supply cylinder while rotating the supply screw at a constant speed with the pressure relief plunger inserted into the pressure relief chamber formed in communication with the material passage in the supply head. are kneaded by the supply screw and pushed into the supply head.

The rubber material supplied to the supply head passes through the material passage in the supply head and enters the metering cylinder.
The metering plunger in the free state is gradually pushed up, and the rubber material is filled into the metering cylinder. At this time, since the rubber material is gradually pushed in only by the rotational force of the supply screw, the pressure applied to the rubber material is about half that of the conventional case. Then, when the metering plunger rises to the set position, the supply screw stops rotating.

Next, the pressure relief plunger is pulled out from the pressure relief chamber to lower the pressure inside the metering cylinder, and then the metering plunger is pushed into the metering cylinder by a predetermined stroke to release a predetermined amount from the extrusion part of the supply head. Extrude heavy rubber material and cut the base of the rubber material with a cutting blade.

[0013] By repeating the above operation, a lump of rubber material is continuously produced, but the rubber material is gradually pushed into the supply head only by the rotational force of the supply screw, and the pressure is released by the pressure relief plunger. The pressure of the rubber material remains relatively low as it is withdrawn from the chamber to reduce the pressure within the metering cylinder.

[0014] Therefore, there is almost no local density difference caused by the high pressure in the rubber material pushed into the supply head, and the compression ratio of the rubber material in the metering cylinder is almost constant every time it is extruded, so it remains constant without variation. Can make heavy rubber material lumps.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

First, the schematic configuration of the rubber material preparation device is shown in FIG.
To explain, 1 is a supply head, and within the supply head 1, a measuring cylinder 3 is provided vertically, and a material passage 1b is formed in the horizontal direction and around the lower part of the measuring cylinder 3. The inside of the measuring cylinder 3 communicates with a part of the material passage 1b at its lower end, and the material passage below the measuring cylinder 3 is open as the extrusion part 1a. This extrusion part 1
a is closed by a closing member 13 connected to the piston rod of a hydraulic cylinder 15 provided below.

Furthermore, a material supply cylinder 4 is connected to the right end of the supply head 1 so as to push the material therein. The material supply cylinder 4 is formed with an input port 4a for inputting a band-shaped rubber material. will be placed in

A pressure relief chamber 1c is located on the left side of the supply head 1.
is formed in communication with the material passage 1b, and its pressure relief chamber 1c
A pressure relief plunger 12 is inserted into the inside from the outside. The pressure relief plunger 12 is connected to the tip of a piston rod of a hydraulic cylinder 14, and is moved by the operation of the hydraulic cylinder 14.

Furthermore, a metering plunger 5 of a predetermined length is fitted into the metering cylinder 3 so as to be movable up and down with its upper portion projecting upward.

Above the supply head 1 is a metering plunger 5.
An extrusion cylinder 8 for extruding rubber material by pressing down is arranged vertically with its piston rod facing downward. A stopper 9, which the tip of the metering plunger 5 contacts, is replaceably attached to the tip of the piston rod, and by changing the thickness of the stopper 9, the weight of the rubber material mass to be extruded can be changed.

Reference numeral 10 denotes a proximity switch for detecting the rise of the metering plunger, which is attached near the stopper 9, and outputs a detection signal when the metering plunger 5 rises and comes into contact with the stopper 9.

Reference numeral 11 denotes a cutting blade for cutting the rubber material, which is disposed below the supply head 1, moves horizontally along the lower surface of the extrusion section 1a, and cuts the extruded rubber material at its base.

Next, a material supply method for the rubber material preparation apparatus will be explained with reference to FIG.

First, the rubber material preparation device is in the state shown in FIG. 1A, that is, the closing member 13 closes the extrusion part 1a, the pressure relief plunger 12 is inserted into the pressure relief chamber 1c, and the metering plunger 5 is inserted into the metering cylinder 3. It is inserted almost to the bottom end. Note that the metering plunger 5 is slightly lifted from its lowering end, and a portion communicating with the material passage 1b is formed on the lower side of the metering plunger 5.

In this state, the motor 6 is driven to rotate, and the supply screw 7 is rotated at a constant speed. A band-shaped dough (rubber material) is introduced into the material supply cylinder 4 through the input port 4a, and while being kneaded by the supply screw 7, the rubber material advances leftward in FIG. 1A and is forced into the supply head 1.

Furthermore, by supplying the rubber material to the supply head 1, the rubber material passes through the material passage 1b and is
The rubber material enters the measuring cylinder 3 and gradually pushes up the free measuring plunger 5, filling the measuring cylinder 3 with rubber material (FIG. 1B). At this time, since the rubber material is gradually pushed in only by the rotational force of the supply screw 7, the pressure applied to the rubber material is about half that when a conventional pushing cylinder is used.

When the tip of the metering plunger 5 comes into contact with the stopper 9, this is detected by the proximity switch 10, and at this time, the motor 6 stops and the supply screw 7
rotation stops.

Next, as shown in FIG. 1C, the pressure relief plunger 12 is pulled out from the pressure relief chamber 1c by a certain stroke by the operation of the fluid pressure cylinder 14, and is held as it is for a certain period of time, for example, 5 seconds. Note that this holding time can be arbitrarily determined depending on the rubber material and the conditions of the device, and may be set to 0 seconds, for example.

In this manner, by pulling out the pressure relief plunger 12 from the pressure relief chamber 1c communicating with the material passage 1b, the pressure of the rubber material in the measuring cylinder 3 is appropriately reduced, and the rubber material is There are almost no local density differences inside.

Next, after the pressure release holding time has elapsed, as shown in FIG. 1D, the closing member 13 closes the fluid pressure cylinder (15
), and an extrusion cylinder (8), not shown, lowers its piston rod. Then, the piston rod pushes the metering plunger 5 into the metering cylinder 3 via the stopper 9, whereby the rubber material is extruded to the outside from the extrusion portion 1a. Then, when the metering plunger 5 stops at the lower end, a measured constant weight of rubber material is extruded from the extrusion section 1a.

In this state, the cutting blade 11 moves to cut off a certain weight of the rubber material extruded from the extrusion part 1a.
A rubber material mass is produced.

Subsequently, the extrusion cylinder (8) again raises its piston rod and stopper 9 to the position shown in FIG. The pressure relief plunger 12 is communicated with the passage 1b, and the pressure relief plunger 12 is returned into the pressure relief chamber 1c (FIG. 1A).

Then, the supply screw 7 is rotated again, and in the same manner as described above, the rubber material is filled into the measuring cylinder 3, the pressure relief plunger 12 is pulled out, and extrusion is performed by the extrusion cylinder 8, and the above-mentioned operations are performed. By repeating this process, rubber material lumps are created one after another.

Graphs A and B in FIG. 2 show experimental results when a rubber material was extruded using the above-described material supply method, and show changes in the weight of the rubber material lump with respect to the number of extrusions of the rubber material.

Here, graph A shows the change in weight of the rubber material lump when the rubber material lump is extruded using the band-shaped rubber material immediately after being kneaded with a kneading roller, and graph B shows the change in the weight of the rubber material lump after being kneaded. The graph shows the change in weight of the rubber material mass when the rubber material mass was extruded using a band-shaped rubber material that had been left for about one week after the extrusion. Also, curves A1 and B in each graph
1 is a case where the holding time of the pressure relief plunger 12 in the pulled out state is 0 seconds, and curves A2 and B2 are cases where the holding time is 5 seconds.

As can be seen from graphs A and B, the variation in the weight of the rubber material mass is about 0.
07g, the variation in the weight of the rubber material lumps is greatly reduced to about 1/3 compared to the conventional method, and it is possible to extrude rubber material lumps with accurate weights. Furthermore, from graphs A and B, it is possible to extrude rubber material lumps with little variation regardless of the condition of the band-shaped rubber material used, and the variation in rubber material lumps between different manufacturing lots is also reduced. be able to.

[0037]

As explained above, according to the material supply method of the rubber material preparation device of the present invention, by rotating the supply screw in the material supply cylinder, the rubber material is pushed into the supply head and into the measuring cylinder. Since the pressure relief plunger is pulled out of the pressure relief chamber to reduce the pressure in the metering cylinder, the pressure applied to the rubber material is relatively low, and the rubber material pushed into the feed head is partially Almost no density difference occurs. Therefore, the compression ratio of the rubber material in the measuring cylinder becomes almost constant for each number of extrusions, and it is possible to continuously produce rubber material lumps of constant weight without variation. Furthermore, variations in the weight of rubber material blocks produced between different production lots can also be reduced.

Furthermore, since the pushing cylinder used in the conventional rubber material preparation apparatus is not required, equipment costs can be reduced. Furthermore, unlike conventional rubber material preparation devices, the supply screw does not move inside the material supply cylinder by the push cylinder, so the tape-shaped rubber material may be forcibly pulled and cut at the input port of the material supply cylinder. No problems will occur.

[Brief explanation of drawings]

FIG. 1 is a process explanatory diagram of a material supply method of a rubber material preparation device.

FIG. 2 is a graph showing the change in weight of a rubber material lump with respect to the number of extrusions.

FIG. 3 is a schematic configuration diagram of a rubber material preparation device.

FIG. 4 is a process explanatory diagram of a conventional material supply method.

FIG. 5 is a graph showing the change in weight of a rubber material lump with respect to the number of conventional extrusions.

[Explanation of symbols]

1-feeding head, 1a-extrusion section, 1b-material path, 1c
- pressure relief chamber, 3 - metering cylinder, 4 - material supply cylinder, 5 - metering plunger, 7 - supply screw, 12 - pressure relief plunger.

Claims (1)

[Claims] Claim 1: A metering cylinder is filled with rubber material introduced into a material supply cylinder through a material passage in a supply head, and a metering plunger is pushed into the metering cylinder, whereby a constant amount of rubber material is released from the extrusion part of the supply head. In the material supply method of a rubber material preparation device that extrudes and supplies a quantity of rubber material, a pressure relief plunger is fitted into a pressure relief chamber formed in communication with a material passage in the supply head, and a pressure relief plunger is inserted into a pressure relief chamber formed in communication with a material passage in the supply head, and The supply screw was rotated to push the rubber material into the supply head to fill the metering cylinder, and then the pressure relief plunger was pulled out of the pressure relief chamber to once lower the pressure in the metering cylinder. A method for supplying a material for a rubber material preparation device, characterized in that a metering plunger is then pushed into the metering cylinder and the rubber material is extruded from an extrusion section of the supply head.