JPH043785Y2 - - Google Patents

Description

[Detailed description of the invention] <Technical field> The present invention relates to a raw material filling device for foam molding, in which expandable thermoplastic resin particles made of polystyrene or the like are filled into the cavity of a mold, heated and foamed,
The present invention relates to a filling device for filling resin particles serving as a raw material into the cavity of a mold in so-called bead molding for manufacturing foam molded products.

<Prior art> The raw material filling device for the above-mentioned bead molding basically has a supply port for raw material particles, an inlet for pressurized air, and a filling port that opens into the mold cavity. and a piston rod that slides inside the air cylinder-shaped raw material filler to provide communication with the supply port and the filling port for the raw material particles.
The filling of raw material particles is controlled by blocking or communicating.

Furthermore, the piston rod of the raw material filling device is
It has been devised to also be used for ejecting a foam molded product formed within a mold cavity, and is disclosed in, for example, Japanese Utility Model Publication No. 1859/1983.

In the above prior art, a fixed piston is provided at the rear end of the piston shaft of the filling device,
An auxiliary piston that can move along the shaft is installed in the middle of the shaft, and the air cylinder of the filler is equipped with pressurized air at the rear of the fixed piston of the shaft, between the fixed piston and the auxiliary piston, and in front of the auxiliary piston. By providing several air inlets and controlling the supply of pressurized air to each air inlet,
When filling the raw material, the shaft is at the rear end of the air cylinder, and when the filling of the raw material is completed and foam molding is performed, the filling port of the raw material filling device is closed, so the shaft moves forward and the next formed foam mold When the product is ejected from the mold, the shaft can be moved in two stages so that the shaft advances further.

Among the above actions, when the shaft is moved forward by one step in order to close the filling port,
The shaft is stopped in a fixed position by supporting the pressing force of the air pressure applied to the fixed piston at the rear of the shaft with the pressing force of the air pressure applied to the auxiliary piston at the front.

Therefore, if the pressing force applied to the front of the auxiliary piston is not stronger than the pressing force applied to the fixed piston, the shaft will not stop reliably, the stopping position will change, and the tip surface of the shaft will not match the mold surface. A problem arises that disappears.

Therefore, in the above prior art, the inner diameter of the auxiliary air cylinder on the auxiliary piston side is formed larger than the inner diameter of the main air cylinder on the fixed piston side, and the main air cylinder and auxiliary air cylinder have the same diameter. Even if a constant air pressure is applied, the pressing force applied to the auxiliary piston side is greater than the pressing force applied to the stationary piston side, ensuring reliable stopping at a predetermined position.

However, it is extremely troublesome to separately manufacture and combine the main cylinder and auxiliary cylinder, which have different inner diameters at the front and rear of the air cylinder, and in this case, the outer diameters of the fixed piston and the auxiliary piston also differ. Since it is necessary to use different materials, the processing and manufacturing of the entire raw material filling device is very time-consuming, and there is a problem in that the cost is also high.

<Purpose> Therefore, the purpose of this invention is to solve the problems of the above-mentioned conventional technology, and to create a raw material filler equipped with a double-acting piston mechanism that can perform both the control of filling and the ejection action of foamed molded products. It is reliable in operation, has a simple structure, and is easy to manufacture.
An object of the present invention is to provide a filling device that can reduce manufacturing costs.

<Structure> The structure for achieving the above object includes filling control for filling the raw material particles made of expandable thermoplastic resin into the mold cavity, and heat treatment of the raw material particles in the mold cavity. A piston rod is provided inside the air cylinder and has the function of ejecting the foamed molded product from the mold, and the piston rod moves integrally with the piston rod inside the rear cylindrical portion of the air cylinder at the rear side of the piston rod. A fixed piston is provided, and a movable piston is provided on the front side of the piston rod, movable within the front cylindrical portion of the air cylinder and movable along the axial direction with respect to the piston rod. In a raw material filling device for foam molding, in which air inlets for compressed air for driving the piston are provided at the rear of the fixed piston of the piston rod, between the fixed piston and the movable piston, and in front of the movable piston, the inner diameter of the air cylinder is The rear cylindrical portion and the front cylindrical portion are formed to have the same diameter, and the outer diameter of the rear shaft portion of the piston rod that protrudes toward the rear side of the fixed piston is equal to the outer diameter of the front shaft portion of the piston rod that protrudes toward the front side of the movable piston. It is characterized by being formed larger than the diameter.

<Example> Next, an example of this invention will be described below with reference to the drawings.

FIG. 1 shows the entire raw material filling device 1, which has a cylindrical shape as a whole, and the tip portion is inserted and attached to the mold 2, and the filling port 10 for raw material particles formed at the leading edge is inserted into the mold 2. It opens into the mold cavity 20 of mold 2.
Further, the filling port 10 communicates with a through passage 11 penetrating the inside of the raw material filling device 1, and a supply port 12 for raw material particles and an introduction port 13 for pressurized air for filling are formed in this through passage 11. It has been done. Then, communication and interruption between the raw material particle supply port 12 and the pressure air introduction port 13 and the filling port 10 described above are performed.
It is controlled by the front shaft portion 30 of the piston rod 3, which slides through the through passage 11.
The basic structure of the raw material filling device 1 described above is the same as that of a conventional material filling device.

Next, the piston rod 3 is moved to a cylinder portion 4 as an air cylinder formed above the raw material filling device 1.
The entire cylinder part 4 has a cylindrical shape with approximately the same inner diameter, and a partition part 40 protruding inwardly is formed in the middle in the axial direction to separate the front cylinder part 41 and the rear cylinder part. It is divided into 42 parts. In the cylinder part 4, pressure air supply ports 43, 44,
45 is formed.

Further, a movable piston 50 is attached inside the front cylindrical portion 41 of the cylinder portion 4 in the front shaft portion 30 of the piston rod 3.
0 is formed to be slidable in the axial direction with respect to the front shaft portion 30 of the piston rod 3. Further, the front piston 50 has an extension cylindrical portion 51 that protrudes rearward.
is formed, and the length of the piston rod 3 protruding toward the mold cavity 20, which will be described later, can be set depending on the length of the extension cylinder portion 51. Of the front shaft portion 30 of the piston rod 3, the rear cylindrical portion 42 of the cylinder portion 4
A fixed piston 52 is installed inside the
This fixed piston 52 moves together with the piston rod 3.

Next, in the piston rod 3, a rear shaft portion 31 having a larger outer diameter than the front shaft portion 30 is formed behind the fixed piston 52, and this rear shaft portion 31 extends from the rear end of the cylinder portion 4. The anti-rotation piece 32 extends through the filling device 1 to the outside of the filling device 1 and extends to the outer periphery of the rear shaft portion 31 on the outside of the filling device 1.
It penetrates and locks onto a detent shaft 60 formed protruding from the rear of the filling device 1, so that the rear shaft portion 31 does not rotate and can freely move only in the axial direction.

In addition, sealing mechanisms such as O-rings are provided at the sliding parts between the pistons 50 and 52 and the cylinder part 4, and at the penetrating parts between the piston rod 3 and the filler 4, to prevent leakage of pressurized air.

The usage state of the raw material filling device 1 having the above-described structure will be explained in the order of the molding steps with reference to FIGS. 1 to 3.

First, FIG. 1 shows the return process of the piston rod 3 or the filling process of raw material particles after the completion of the molding process, and there are three pressurized air supply ports 4.
Pressurized air is supplied to the supply port 43 of the front cylinder section 41 and the supply port 44 of the partition section 40 among the supply ports 3, 44, and 45.

Then, the movable piston 50 and the fixed piston 52 both move rearward, and the fixed piston 5
The piston rod 3 fixed to 2 is retracted to the rearmost position. Since the front shaft portion 30 of the piston rod 3 is retracted upward from the supply port 12 for raw material particles and the introduction port 13 for pressurized air, the front shaft portion 30 of the piston rod 3 is Particles are supplied and filled into the mold cavity 20 of the mold 2 .

Next, FIG. 2 shows a molding process in which raw material particles are filled and then heated and foamed.
Pressurized air is supplied to the supply port 43 at the frontmost part of the cylinder 1 and the supply port 45 at the rearmost part of the rear cylinder part 42.

Then, the fixed piston 52 moves forward, and the piston rod 3 integrated with the fixed piston 52 moves forward.
also move forward. Furthermore, the movable piston 50 remains pressed against the rear of the front cylinder section 41, that is, the front surface of the partition section 40.

That is, as shown in detail in FIG. 3, when the fixed piston 52 moving forward from the rear comes into contact with the extension cylindrical portion 51 of the movable piston 50 and tries to push it forward, the movable piston 50 Pressurized air from the side applies pressure to the rear side.

At this time, the pressure of the compressed air supplied to the rear of the fixed piston 52 and the pressure of the compressed air supplied to the front of the movable piston 50 are exactly the same, but the pressure receiving area on the rear side of the fixed piston 52 is
The area is calculated by subtracting the outer diameter of the rear shaft portion 31 of the piston rod 3 from the inner diameter of the rear cylindrical portion 42 of the cylinder portion 4, and the pressure receiving area on the front side of the movable piston 50 is This is the area obtained by subtracting the outer diameter of the front shaft portion 30 of the piston rod 3 from the inner diameter.

The inner diameters of the rear cylindrical portion 42 and the front cylindrical portion 41 are the same, but the outer diameter of the rear cylindrical portion 32 is the same as that of the front cylindrical portion 41.
Since the outer diameter is larger than the outer diameter of 0, the pressure receiving area on the movable piston 50 side is wider than the pressure receiving area on the fixed piston 52 side, and the pressing force on the rear side of the movable piston 50 is stronger.

Therefore, even if the fixed piston 52 tries to move forward, once it comes into contact with the movable piston 50, it cannot move any further against the pressing force of the movable piston 50, and the forward movement is surely stopped, leaving this position. It will stop.

At this time, the tip of the front shaft portion 30 of the piston rod 3 closes the through passage 11 and closes the filling port 10 of the pressure air introduction port 13 and the raw material particle supply port 12.
At the same time, the opening of the filling port 10 is closed with the tip surface of the piston rod 3, so that the surface of the mold cavity 20 and the tip surface of the piston rod 3 are flush with each other. In this state, mold cavity 2
A heating medium such as heated steam is supplied into the chamber to heat and foam the raw material particles, thereby producing a foamed molded product F.

Next, FIG. 4 shows the mold removal process in which the molded foamed product is ejected from the mold 2, and pressure is applied to the supply port 45 at the rearmost part of the rear cylinder section 42 and the supply port 44 of the partition section 40. Introduce air.

Then, as the movable piston 50 moves forward, the fixed piston 52 can also move forward, and the fixed piston 52 moves forward until it comes into contact with the partition part 40. Then, the tip of the front shaft portion 30 of the piston rod 3 moves to protrude from the same surface as the filling port 10 into the mold cavity 20 further forward, and
The foamed molded product F in the mold cavity 20 is pushed out from the mold 2 and removed from the mold.

One cycle of the molding process is completed through each of the above steps, and the foamed molded product F is manufactured by repeating each step in sequence.

Of the raw material filling device 1 described above, the structure of the raw material particle supply port 12, the pressure air introduction port 13, the filling port 10, etc., the mounting structure of the filling device 1 and the mold 2, etc. are conventional and conventional. It can be implemented with a structure similar to that of the filling device, and modifications other than the illustrated embodiment are possible.

Further, as a rotation prevention mechanism for the piston rod 3, as shown in the illustrated embodiment, the piston rod 3
The rear shaft portion 31 of the filling device 1 is passed through the rear portion of the filling device 1,
In addition to the structure that projects outside the filling device 1 and restricts the rotation of the rear shaft portion 31 by engagement between the detent piece 32 and the detent shaft 60, Although axial movement is possible,
An appropriate engagement structure that can prevent rotation in the circumferential direction may be provided inside the filling device 1, and may also be provided inside the filling device 1 to engage with the rear shaft portion 31 or the front shaft portion 30 to prevent rotation. However, an uneven shape may be formed as appropriate to enable movement in the axial direction.
For example, if the piston rod 3 and the cylinder portion 4 or the through passage 11 of the filler 1 that slide thereon are formed into an irregular shape other than circular, it is possible to achieve the anti-rotation function.

The effect of the above-mentioned anti-rotation mechanism is that when the tip of the piston rod 3 protrudes the foam molded product F, when the abutting surface against the foam molded product F rotates, the piston rod 3 is attached to the surface of the foam molded product F.
In addition, the rotation of the piston rod 3 applies a force to rotate or twist the foam molded product F.
Since there is a problem that the foamed molded product F cannot be ejected smoothly in a straight line, and the mold release function cannot be achieved reliably, as mentioned above, the piston rod 3
The anti-rotation mechanism is effective to prevent the rotation of the

Furthermore, in a normal mold 2, the filling device 1 is provided at a flat part of the mold surface of the mold 2, and the tip end surface of the piston rod 3 is also formed flat, but the shape of the mold surface of the mold 2 is complicated, and in order to conform to this mold surface shape, the tip surface of the piston rod 3 cannot be formed flat, and the tip surface may be curved, sloped, or curved.
Alternatively, when the piston rod 3 rotates when unevenness such as a step is formed, the piston rod 3
The tip surface of the mold 2 no longer matches the mold surface of the mold 2,
The above-described rotation prevention mechanism can completely solve the problems of the foamed molded product F having a dirty finish and decreasing its commercial value.

Note that the pressurized air supplied to each supply port 43, 44, and 45 for operating the piston rod 3 is the same as the air for filling raw materials and other parts of the molding device.
Normal pressure air supplied from a common air pipe can be used, and the pressure of the compressed air is 2 to 7.
It is carried out at around Kg/cm ² G.

<Effects> According to the raw material filling device 1 of this invention configured as described above, the piston rod 3 is filled by the operation of the fixed piston 52 and the movable piston 50 attached to the piston rod 3 that slides within the cylinder portion 4. is moved forward in two stages, and can be used both for filling and blocking raw material particles and for ejecting the formed foamed product F from the mold.

As for the structure of the operating part of the piston rod 3, the fixed piston 5 of the cylinder section 4 is
The inner diameter of the rear cylindrical portion 42 that accommodates the piston rod 2 and the inner diameter of the front cylindrical portion 41 that accommodates the movable piston 50 are the same. 31 is made larger than the outer diameter of the front shaft portion 30 in front of the movable piston 50, the fixed piston 52 is reliably stopped at a constant forward position when filling with raw material particles is completed. It is something that can be done.

That is, when the fixed piston 52 is moved forward by supplying pressurized air to the rear thereof, the fixed piston 52 and the movable piston 50 are pushed toward each other when the fixed piston 52 comes into contact with the movable piston 50. become.

At this time, the pressure of the pressurized air that pushes the fixed piston 52 and the pressure of the pressurized air that pushes the movable piston 50 are the same, but due to the difference in the outer diameter of the rear shaft section 31 and the front shaft section 30 described above. Then, fixed piston 5
2, the pressure receiving area of the movable piston 50 is larger than that of the movable piston 50, and therefore the pushing force of the movable piston 50 against the fixed piston 52 is greater, so the fixed piston 52 moves forward from the position where it contacts the movable piston 50. If you can't, it will definitely stop.

As a means for stopping the fixed piston 52, in a conventional filling device, the outer diameter of the piston rod is kept constant, and the inner diameter of the cylinder portion is made larger on the movable piston side than on the fixed piston side. Because the surface area was large, manufacturing was extremely troublesome, as the inner diameter of the cylinder, which was difficult to process, had to be changed between the front and rear parts, and the fixed and movable pistons had different outer diameters. In contrast to the technically difficult problems, this idea is relatively easy to process.
By simply changing the outer diameter of the piston rod 3 between the front shaft section 30 and the rear shaft section 31, the inner diameter of the cylinder section 4 and the outer diameters of the fixed piston 52 and the movable piston 50 can be completely the same, making it extremely easy to process. It is easy to manufacture and the manufacturing cost is low.

In particular, the larger the diameter of cylinders and pistons, the higher the processing precision required, making it difficult to maintain airtightness and smooth operation, and requiring advanced manufacturing technology. It is extremely difficult to form the cylinder part 4 to a large diameter, and there are many processing problems, but in the case of this invention, it is sufficient to form the entire cylinder part 4 with a fixed diameter dimension. , the above-mentioned difficulties of the prior art were completely resolved.

Furthermore, parts such as O-rings attached to cylinders and pistons and processing tools can be used in common as long as they have the same diameter, and the labor of manufacturing, assembly, and maintenance and inspection can be saved.

As mentioned above, at the same time as controlling the filling of raw material particles,
The raw material filling device 1, which operates in two stages and can also be used for removing the foam molded product F, has an extremely simple structure.
It can be manufactured at low cost, can greatly contribute to reducing the cost of the entire molding device, and exhibits various excellent practical effects.

[Brief explanation of the drawing]

The figure shows an example of this invention.
The figure shows a cross-sectional view when the piston rod is retracted, FIG. 2 is a cross-sectional view when the piston rod moves forward in the first stage, FIG. 3 is an enlarged view of the main part of the previous figure, and FIG. 1... Filler, 3... Piston rod, 30...
...Front shaft part, 31... Rear shaft part, 32... Detent piece, 4... Cylinder part, 41... Front cylinder part, 4
2... Rear cylindrical portion, 43, 44, 45... Pressure air supply port, 50... Movable piston, 52... Fixed piston, 60... Anti-rotation shaft.

Claims (1)

[Claims for Utility Model Registration] 1. A foamed molded product obtained by filling a mold cavity with raw material particles made of a foamable thermoplastic resin and heat-treating the raw material particles in the mold cavity. A piston rod is provided inside the air cylinder, which also serves as an ejector for protruding from the mold, and a fixed piston is provided on the rear side of the piston rod, which moves integrally with the piston rod within the rear cylindrical portion of the air cylinder. A movable piston is provided on the front side, which moves within the front cylindrical portion of the air cylinder and is movable along the axial direction with respect to the piston rod. In a raw material filling device for foam molding, air inlets for compressed air for driving the piston are provided between the fixed piston and the movable piston, and in front of the movable piston.
The inner diameter of the air cylinder was formed to be the same for the rear cylinder part and the front cylinder part, and the outer diameter of the rear shaft part of the piston rod that protruded toward the rear side of the fixed piston was made to protrude toward the front side of the movable piston. A raw material filling device for foam molding, characterized in that the outer diameter of the front shaft portion of the piston rod is larger than that of the piston rod. 2. The raw material filling device for foam molding according to claim 1 of the above-mentioned utility model registration claim, wherein the piston rod is free to move in the axial direction and is provided with a rotation prevention mechanism to restrict rotation.