JPH0145404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses waste plastics, etc., as raw materials, which are used for surveying or to clearly indicate land boundaries, etc., with plastic or metal sign caps that display measurement points on the top end. The present invention relates to a method for manufacturing plastic surveying piles.

In recent years, surveying piles made of plastic made from waste plastic or the like have been used instead of wooden or concrete surveying piles. Such surveying piles are light, do not decay, are inexpensive, and are extremely useful in terms of making effective use of waste plastics, which have become a pollution problem. Conventionally, this type of plastic surveying stake has been manufactured by melting waste plastic, molding it into a stick of a certain length by extrusion molding or injection molding, and then capping the top end with a marker cap. However, when molding these products, a lot of time is spent on cooling, making the overall efficiency of the equipment extremely low.Furthermore, after molding the rod-shaped body, a process of capping the top end with a marking cap is required, which makes production difficult. The disadvantage was that the efficiency was further reduced. Furthermore, the marker caps of surveying stakes obtained by the above method tend to come off easily, which poses a practical problem.

The present inventor has solved the drawbacks of such conventional methods.
The present invention was arrived at as a result of extensive research to provide a method for manufacturing plastic surveying piles with high production efficiency. That is, in the method of the present invention, a cylindrical mold having an opening for injecting molten plastic at the tip and an opening for inserting a marker cap at the rear end is intermittently rotated, and during the rotation path, the rear end of the mold is The marker cap is inserted through the opening, and then the tip of the mold into which the marker cap is inserted is slid into contact with the fixing plate to close the tip opening of the mold, and the tip opening engages with the opening provided in the fixing plate. When the molten plastic fills the mold, the valve mechanism is opened to supply molten plastic from the extruder into the mold, and when the cap retreats to the rear end of the mold due to the pressure of the molten plastic filled in the mold, the valve mechanism is closed. The supply of molten plastic is stopped, and then both ends of the mold filled with molten plastic are brought into contact with a sliding plate, and the molten plastic is passed through a cooling tank with the openings at both ends of the mold closed. A plastic surveying method characterized in that the surveying stake is continuously formed by cooling and solidifying the mold, then releasing the openings at both ends of the mold from the sliding plate and taking out the surveying stake fixed inside the mold. This is a method for manufacturing piles.

Next, one embodiment of the present invention will be described with reference to the drawings. The method of the present invention is implemented by the steps illustrated in FIG. 1, and an example of an apparatus that can efficiently implement this method is shown in FIGS. 2 to 5.

The apparatus for manufacturing a plastic surveying pile according to the present invention includes a plurality of molds 1 attached to support plates 7, 7' attached to a rotating shaft 6, a mechanism for intermittently rotating this shaft, a cap insertion station A, It consists of a raw material injection station B, a cooling station C, a pre-extrusion station D and an ejection station E.

The mold 1 has a cone-shaped tip, and has a raw material injection port 2 such as molten plastic at the tip of the cone, and a surveying pile 40 that has been cooled and solidified at the rear end.
It consists of a cylindrical mold body 4 having an opening 3 for taking out, and the mold has a small diameter abdomen so that the molded object can be pressed with an extrusion rod inserted into the raw material injection port and taken out from the rear end opening. The rear end has a large diameter, and each part is connected by a taper.

As shown in FIGS. 2 to 5, this mold 1 consists of two disc-shaped support plates 7 and 7' each having a plurality of recesses provided at regular intervals on the circumference, which are attached to both ends of a rotating shaft 6. Arrived,
A mold is fixed parallel to the rotation axis between the recesses of the two support plates. This mold rotates around a shaft 6 within a cooling water tank 5. This rotating shaft 6 has a rotating plate 8 that protrudes radially between adjacent concave portions of a disc-shaped support plate 7, and this rotating plate is connected via a hinge 11 to the tip of a rod 10 of a rotating cylinder 9 that is attached to a machine base. By abutting and pressing the attached metal fitting 12 against the rotating plate 8, the rotating shaft 6 can be rotated by a certain angle. Further, the metal fitting 12 maintains a state in which it presses and holds the rotary plate when the rod is extended, and is configured to be rotatable when the rod is withdrawn so as not to engage with an adjacent rotary plate. The intermittent rotation mechanism of the rotating shaft is not limited to the illustrated cylinder type, but any other mechanism such as a combination of a pinion and a rack, a drive gear mechanism, or a chain drive mechanism may be employed.

A stopper device is separately provided to ensure that the rotary shaft 6 is stopped at a predetermined position after being rotated by a predetermined angle. This device has a plurality of openings 1 provided on the same circumference of the support plate 7 at the same intervals as the recesses.
3, and a positioning cylinder 14 that engages with this opening each time. Further, in order to control the rotational speed of the rotating shaft 6, a rotation adjusting device 15 is provided which brings a plastic piece into contact with the support plate 7 and adjusts the pressing force of the plastic piece against the support plate.

The cap insertion station A is for inserting the marker cap 16 into the rear end opening of the mold 1, and is composed of a cap supply cylinder 17 and a cap insertion cylinder 18. The cap supply tube 17 is provided so that its tip is close to the rear end opening of the mold 1, and an opening for taking out the cap from the tube is provided on the side of the tube that comes into contact with the mold. The opposite side is provided with an opening through which a rod of a cap insertion cylinder, which will be described later, is inserted. A cap insertion cylinder wanderer 18 is provided at the rear end of the mold via a cap supply cylinder 17, and presses the lowest layer of caps supplied to the cap supply cylinder to insert this cap into the mold. . This cylinder is configured to operate after detecting the operation of the positioning cylinder 14 and detecting that the mold has rotated to a predetermined position and stopped, and to return to the original position after inserting the cap into the mold. There is.

The raw material injection station B is for injecting molten plastic into the mold, and is provided with an extruder 19 for supplying molten plastic and a raw material injection detection mechanism. This extruder 19 is a vent type extruder consisting of a cylindrical main body 21 having an opening 20 at the top and an extrusion screw 22, and is equipped with a connecting pipe 23 having a valve mechanism 24 at its extrusion port. The other end of this connecting pipe is connected to an opening provided in a fixed plate 41 connected to a sliding plate to be described later. The valve mechanism 24 provided in the connecting pipe consists of an elevating cylinder 26 and a valve rod 28 connected to this cylinder, and by raising and lowering this valve rod and aligning the opening 27 formed in this rod with the connecting pipe. The flow path can be connected or disconnected as appropriate.
This valve rod 28 descends to close the flow path while the rotating shaft 6 is in operation. Then, when the tip of the mold 1 slides on the fixing plate 41 and the die tip opening engages with the opening of the fixing plate, the extruder 19 is activated by operating the lifting cylinder 26 to raise the valve rod 28. The extrusion port and the raw material injection port 2 of the mold are communicated with each other so that molten plastic is injected into the mold.
Further, this station is provided with a raw material injection detection mechanism on the side opposite to the extruder. This mechanism consists of a detection device such as a push switch, and when the injection of molten plastic into the mold is completed, the indicator cap 16 inserted into the rear end opening of the mold is retracted as the internal pressure of the molten plastic increases. This movement of the cap is detected by a push switch 31 via a rod 30 of a detection cylinder 29 extended into the opening at the rear end of the mold, and a signal from the detection is given to the lifting cylinder 26 to return it to its lowered position. injection of molten plastic into the mold.

The cooling station C cools and solidifies the molten plastic injected into the mold, and includes a cooling water tank 5 for cooling the mold and sliding plates 25 and 25' for preventing the molten plastic filled in the mold from flowing out. It is configured. Also, this station has cooling water tank 5.
It is located below the surface of the water. Water is supplied to the cooling water tank at all times or as needed by a cooling pipe 32 and a valve attached to the pipe, and the heated water overflows and drains from an overflow pipe 33. Note that the cooling liquid is not limited to water, and any liquid can be used. Inside this water tank are sliding plates 25 and 25' that slide both ends of the mold 1 to close the opening and prevent the molten plastic from flowing out.
is provided. This sliding plate may close the opening of the mold until the molten plastic solidifies in the water tank. Further, a sliding plate 25 on which the mold tip slides is connected to a fixed plate 41 provided at the raw material injection station B in a smooth state.

The preliminary extrusion station D slightly moves the pile that has been cooled and solidified in the mold to facilitate the extraction of the survey pile at the extraction station E, which will be described later.
A pressing cylinder 34 with a large pressing force and a short stroke is provided on the tip side of the mold. This cylinder is constructed so that an extrusion rod 36 connected to a piston rod 35 is inserted through a raw material inlet of the mold to press and move the surveying pile a little, and then retreat back to its original position. Alternatively, the piston rod of the cylinder may directly press the pile.

The take-out station E is for further pressing the survey pile 40 that has been moved slightly at the station D to take it out from the mold. The connected take-out rod 39 is pushed into the raw material injection port of the mold to take out the surveying pile. Note that a carry-out roller (not shown) may be mounted on a shaft behind the rear end of the mold of the take-out station for transporting the taken-out survey pile to the next process. This roller carries out the surveying pile pushed out by the operation of the cylinder 37 to the next process while holding it therebetween, and is driven by a drive device.

Next, a method for manufacturing surveying piles using the apparatus configured as described above will be explained with reference to FIG.

First, the marker cap 16 is inserted into the mold from the rear end opening 3 of the mold 1. That is, the mold into which the cap is to be inserted is stopped at the station A, and the cap fed by the cap supply cylinder 17 is pressed by the cap insertion cylinder 18 and inserted into the mold.

After the above operations are completed, the rotary cylinder 9 is operated, and the metal fitting 12 attached to the piston rod 10 of this cylinder is brought into contact with and pressed against the rotary plate 8 provided radially on the support plate 7. Rotate by a certain angle. and positioning cylinder 14
to completely stop the axis. Along with this, a new mold is moved to the cap insertion station A and the above operation is performed, and the mold into which the cap has been inserted is moved to the next raw material injection station B. When the mold moves to the raw material injection station B, the leading end of the mold comes into contact with the fixed plate 41 and slides, and stops when it engages with an opening provided in the fixed plate.

Molten plastic is injected into the mold at material injection station B. That is, when the operation of the positioning cylinder 14 is detected and it is confirmed that the mold 1 into which the raw material is to be injected has stopped at this station,
The plastic injection detection cylinder 29 is activated and the rod 30 of this cylinder is slightly inserted into the rear end opening 3 of the mold, and the lifting cylinder 2
6 is activated to raise the valve rod 28 and communicate the extrusion port of the extruder 19 with the raw material injection port 2 of the mold. This causes the molten plastic to be injected into the mold by the screw 22 of the extruder 19. This mold is constantly supplied with excess plastic, which increases the pressure inside the mold, and the cap inserted into the opening at the rear end of the mold moves toward the opening at the rear end of the mold. The cap abuts the piston rod 30 of the detection cylinder 29. This retraction of the rod is detected by the push switch 31, and this signal is given to the lifting cylinder 26 to automatically lower it, and the flow of molten plastic is temporarily interrupted by the valve rod 28. When the supply of molten plastic by the extrusion screw is cut off, the pressure inside the cylinder of the extruder increases, but the vent type extruder is safe because the abnormal pressure of the extruder is absorbed by the opening 20 provided in the cylindrical body 21.

After the above operations are completed, positioning cylinder 1
4 is activated to release the fixation of the rotating shaft by this cylinder, and then the rotating cylinder 9 is activated to rotate the shaft. Along with this, a new mold is moved to the injection station B, and the above operation is performed. On the other hand, the mold filled with molten plastic moves to the next cooling station C, where it is cooled by immersion in water in the cooling water tank 5, and the injection operation continues at the injection station B into another mold. During this time, each cooling station remains stationary, and the opening of the mold is kept closed by sliding plates 25, 25', during which time the molten plastic is cooled and solidified.

After passing through cooling station C, the mold then moves to pre-extrusion station D. At this station D, the extrusion cylinder 34 is operated to push the extrusion rod 36 connected to the rod 35 into the tip opening 2 of the mold, thereby slightly moving the cooled and solidified survey pile toward the rear end.

At the take-out station E, the take-out cylinder 37 is actuated to push the take-out rod 39 connected to the rod 38 into the opening at the end of the mold, and the survey stake preliminarily extruded at the station D is taken out from the mold. After the surveying pile has been taken out, the mold is moved to the cap insertion station A by rotating the shaft again by the operation of the rotary cylinder 9, and the surveying pile is removed by repeating the operations at each of the stations described above. Can be produced continuously.

Incidentally, the rotational drive of the mold by the rotary cylinder and the operation of each mechanism in each station A, B, C, D, and E can all be performed automatically in conjunction with each other in sequence by a pusher switch, a limit switch, or the like.

As described above, in the present invention, surveying piles can be formed continuously because the mold is formed through the steps of inserting a marker cap into the mold, injecting molten plastic, cooling and solidifying, and taking out the mold while rotating the mold. Not only can automation and labor-saving be easily achieved, molding can be performed very efficiently, and the equipment is also compact.
In particular, by using waste plastic as a raw material, it is possible to quickly solve the problem of pollution caused by waste plastic, which has become a problem recently, and it is also possible to provide a very inexpensive surveying pile. Furthermore, in the surveying pile obtained by the present invention, the marker cap for injecting molten plastic into the marker cap is completely capped and fixed to the upper end of the pile, and unlike conventional surveying piles, the cap never comes off.

[Brief explanation of drawings]

Fig. 1 is an exploded explanatory diagram for explaining the method of the present invention, Fig. 2 is a front view of the apparatus of the present invention, Figs. 3 and 4 are left and right side views, respectively, and Fig. 5 is a plan view. It is. A...Cap insertion station, B...Raw material injection station, C...Cooling station, D
... Pre-extrusion station, E ... Take-out station, 1 ... Mold, 2 ... Raw material injection port, 3 ...
... Rear end opening, 5 ... Cooling water tank, 6 ... Rotating shaft, 7
... Support plate, 16 ... Marker cap, 17 ... Cap supply cylinder, 18 ... Cap insertion cylinder,
19...Bent type extruder, 24...Valve mechanism, 2
5, 25'...Sliding plate, 34...Press cylinder,
37...Take-out cylinder, 40...Surveying pile.

Claims (1)

[Claims] 1 While intermittently rotating a cylindrical mold having an opening for injection of molten plastic at the tip and an opening for inserting a marker cap at the rear end, insert the marker cap from the rear end opening of each mold during the rotation path. Then, the tip of the mold into which the marking cap has been inserted is slid into contact with the fixing plate to close the tip opening of the die, and when the tip opening engages with the opening provided in the fixing plate. , the valve mechanism is opened to supply molten plastic from the extruder into the mold, and when the cap retreats to the rear end of the mold due to the pressure of the molten plastic filled in the mold, the valve mechanism is closed to supply the molten plastic to the mold. Then, both ends of the mold filled with molten plastic are brought into contact with a sliding plate, and the molten plastic is cooled and solidified by passing it through a cooling tank with both ends of the mold closed. A surveying pile made of plastic, characterized in that the surveying pile is continuously formed by tightening the mold, then releasing the openings at both ends of the mold from the sliding plate, and taking out the surveying pile solidified inside the mold. Production method.