JPS58181620A - Method and apparatus for preparing reticulate material for packaging - Google Patents

Abstract

PURPOSE:To obtain packaging reticulate material by a method wherein a pair of rotary extruding dies revolving in the opposite direction to each other takes high and low speeds repeatedly, continuously and steplessly and portions having different reticulate structures and diameters are formed on a long, cylindrical and reticulate material extruded and then the reticulate material is cut. CONSTITUTION:A stepless variable speed motor and two elliptical gears that synchronize to said stepless variable speed motor and engage with each other are provided and synthetic resin is extruded from a pair of rotary extruding dies that revolve in the opposite direction to each other through the two elliptical gears to prepare continuous cylindrical reticulate material of synthetic resin. In this case, the above-mentioned rotary extruding dies take high and low speeds repeatedly, continuously and steplessly, portions having different reticulate structures and diameters are formed at an equal interval on the extruded long cylindrical reticulate material and the above-said cylindrical reticulate material is cut suitably in the length direction. In this manner, we can obtain the most suitable reticulate material for packaging fruits etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing mesh material for fruit packaging and to an apparatus for directly carrying out the method.

Conventionally, when fruits such as apples, pears, melons, peaches, etc. are stored, transported, and displayed and sold in stores, it is used to prevent the fruits from being scratched or punctured due to contact between the container walls and the fruits. , cylindrical mesh-like foamed polyethylene materials, etc. are often used. Various techniques are known for using this cylindrical mesh foam material as a cushioning packaging material for spherical fruits. That is, when packaging spherical fruits by inserting them into a cylindrical mesh material of equal width, it is desirable to squeeze and fix the bottom of the cylindrical mesh material so that it does not expand. For this reason, some of the known techniques used for packaging fruits include one in which a net is folded in half and a ring-shaped object is fitted inside the folded part to squeeze the bottom part (Utility Model Publication No. 46-28875). (see official bulletin). The part that corresponds to the bottom of the net has a different mesh structure and tube diameter and is squeezed into a small size (Special Publication Publication No. 47-47)
(See Publication No. 098). Adjacent filaments of the bottom net are glued and fixed (see Japanese Utility Model Publication No. 52-31256).

There is a method (see Japanese Patent Laid-Open No. 54-46693) in which a cohesive zone is provided by integrally welding the filaments of the net in the circumferential direction of the bottom.

However, as a mesh material for fruit packaging,
As shown in Japanese Patent No. 7-47098, it is preferable to partially squeeze the net material. This kind of net-like material is normally produced by extruding multiple resins into a ring shape from a pair of extrusion dies that rotate in opposite directions, and then welding them in a state where they intersect with each other. Because you can.

However, in order to squeeze a portion of the net material, it is necessary to change the extrusion speed, or the pulling speed or the rotational speed of the extrusion die. In this case, changing the rotational speed of the extrusion buoy will inevitably change the pulling speed, so the device itself can be simplified. However, as can be seen from the above-mentioned technique, the rotation speed of this extrusion die changes discontinuously, that is, stepwise4, so the resulting net material has a sharp constriction area, making it difficult to fit into the spherical fruit. .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for producing a packaging net material in which the diameter of the constricted portion of the net material is steplessly, ie, continuously, gradually decreased or increased.

According to the present invention, the rotational speed of the rotating extrusion die is changed steplessly and continuously.

Therefore, the diameter of the obtained net-like material increases and decreases steplessly and continuously, making it possible to obtain one that can match the shape of the fruit.

The material of the cylindrical mesh material implemented in the present invention is soft synthetic resin,
Particularly preferred is foamed resin. In the cylindrical mesh material manufactured according to the present invention, where the rotating extrusion die is rotating rapidly, the extruded synthetic resin is pulled in the direction of rotation, and the diameter of the mesh becomes small and the mesh becomes relatively horizontally long. On the other hand, where the rotation is slow, the diameter of the net is large and the mesh becomes relatively elongated. If the mesh is elongated vertically, the mesh can be stretched in the circumferential direction when wrapping fruits, etc. that are larger than the diameter of the tubular mesh material. can be inserted.

Since the net-like material obtained according to the present invention is manufactured as a long body, the narrowed portions having a small diameter are cut and used as individual packaging materials for fruits. However, it is also possible to create a double packaging material by folding back this individual packaging material so that the larger diameter portion becomes the end. Further, even if this individual packaging material is cut into a portion having a larger diameter, a packaging material can be obtained in the same manner.

As mentioned above, in order to extrude foamable molten resin from an extruder and give a shape to the foamed cylindrical net material when manufacturing the net material, a large number of recesses are formed in the opposing inner circular die and outer annular die, respectively. Molding can be performed by rotating a pair of annular rotary dies in opposite directions and extruding the resin while taking it out.

In carrying out the present invention, the rotational speed of the annular rotary die is continuously and periodically varied using an elliptic bilobal gear (oval gear).

A manufacturing apparatus embodying the present invention will be described in detail below with reference to FIG. 1 and FIGS. 2A, B, and C.

FIG. 1 shows a drive system diagram of an annular rotary die, in which 1 is a continuously variable speed motor, 2 is a chain wheel fixed to the shaft 1a of the continuously variable speed motor 1, and 3 is a chain wheel. It is fixed to the first shaft 4, and both chain wheels 2.3 are interlocked by a chain wheel C1.

A driving elliptical bilobal gear 5 (hereinafter simply referred to as a driving gear) is fixed to the first shaft 4, and this gear 5 is fixed to a driven elliptic bilobal gear 6 (hereinafter simply referred to as a driven gear) fixed to the second shaft 7. ) are meshed with each other.

Therefore, these two gears 5, 6 constitute a continuously variable transmission. A chain wheel 8 is fixed to the second shaft 7, a chain wheel 9 is fixed to the third shaft 10, and both chain wheels 8.
9 are designed to interlock with each other using Cheno C2. A bevel gear 11 is fixed to the third shaft 10, and this bevel gear
It meshes with a bevel gear 12 fixed to a shaft 13.

Now, another bevel gear 14 is fixed to the fourth shaft 13, and this bevel gear 14 meshes with a pair of bevel gears 15, 16, each of which is interlocked with a pair of rotating extrusion dies. The bevel gears 15, 16 therefore rotate in one direction, opposite ffi to each other. The pair of rotating extrusion dies is designated by the numeral 17 with the outer die thereof. These extrusion dies have an extruder 18
Synthetic resin is extruded from it.

FIG. 2 shows the mode of meshing between the driving gear 5 and the driven gear 6, where KM of the driving gear 5 is the major axis, L-N is the minor axis,
Further, klIl of driven gear 6 indicates the short axis, and Qn indicates the long axis. To explain the operation of the driving gear 5 and the driven gear 6, when these gears 5.6 rotate the continuously variable speed motor 1 at a constant speed, the second shaft 7 fixed to the driven gear 6 rotates as shown in FIG. 2A. When meshing occurs at the position shown, the long diameter part KM of the drive gear 5 and the short diameter kllll of the driven gear 6 are on a line and mesh, so the second shaft 7 fixed to the driven gear 6 reaches the maximum rotation speed. Rotate with. At this time, if the cylindrical mesh material extruded from the extrusion die is taken at a constant speed, the third
As shown by P in the figure, the mesh size is minimized. Next, when the two gears 5 and 6 mesh at the C1 position in FIG. 2B, the short diameter portion LN of the driving gear 5 and the long diameter portion nQ of the driven gear 6
Since they are aligned in a straight line and mesh, the second shaft 7 rotates at the minimum rotational speed, and the mesh size becomes the maximum as shown by P2 in FIG. Next, the meshing of both gears 5 and 6 is the second
At the position shown in FIG. C, the mesh size P1 becomes the minimum as in the case of FIG. 2A. In this manner, the minimum mesh size P1 and the maximum mesh size P2 are formed once each while the drive gear 5 rotates half a rotation, and these portions are indicated by A and B in FIG. Also, since it uses an elliptical bilobal gear, the mesh size can be increased and decreased steplessly.

As described above, the product obtained according to the present invention has a cylindrical shape in which the mesh size and the diameter of the tube change steplessly from a small portion to a large portion and from a large portion to a small portion. In order to use this long cylindrical mesh material as a cushioning packaging material for fruits, it must be cut at the short diameter part of the cylindrical section, part A in Figure 3, and fruits should be inserted as shown in Figure 4 A. Bye. It is also possible to use a two-layer structure in which the central part is folded back as an end. Furthermore, fruits can be packaged by cutting the cylindrical part at the short diameter part A and the long diameter part opening, as shown by the opening in FIG.

As described above, the cylindrical mesh material obtained by the present invention can be used for the same purposes as the above-mentioned known packaging materials, and its compatibility is favorable. In particular, according to the present invention, since the mesh/r method and the diameter of the cylinder gradually increase and decrease, it is most suitable as a packaging material for spherical fruits.

Further, according to the present invention, since two elliptical biplane wheels are used as a transmission that changes speed steplessly and periodically, the structure is extremely simple, the transmission is reasonable and reliable, and there is no mesh structure. It can be changed very easily by changing the speed by the step-change motor or the ratio of the short axis/long axis of both gears.

[Brief explanation of the drawing]

Figure 1 is a drive system diagram of the device implementing the present invention, Figure 2A
, B and C are explanatory diagrams for explaining the rotation mode of the elliptic two-shaped gear implemented in the present invention, respectively. 4
Figure A is a front view of a spherical fruit inserted into a net-like material and used for packaging. 1... Stepless variable speed motor 5... Drive elliptical bilobal gear (driving gear) 6... Driven elliptical bilobal gear (driven gear)

Claims (2)

[Claims] (1) In a method of manufacturing a continuous synthetic resin cylindrical mesh material by extruding synthetic resin from a pair of rotary extrusion dies that rotate in opposite directions, the rotary extrusion dies are continuously rotated at low and high speeds. , and steplessly variable speed to form portions with different network structures and diameters at equal intervals on the extruded long cylindrical net material, and cut the cylindrical net material as appropriate in the length direction. A method for producing a packaging net material. (2) In an apparatus for manufacturing a continuous cylindrical mesh material of synthetic resin by extruding synthetic resin from a pair of rotary extrusion dies that rotate in opposite directions, a continuously variable speed motor; 1. An apparatus for making a net-like material for packaging, characterized in that it is equipped with two elliptical gears that mesh with each other, and a rotating gear of an extrusion die that rotates is interlocked with the two elliptic gears.