JPS5929135A - Preparation of cylinder made of cynthetic resin - Google Patents

Abstract

PURPOSE:To obtain the titled cylinder excellent in both bendability and shape holdability and having excellent and durable quality, by a method wherein a synthetic resin sheet is bent by a rule to form a cylinder which is, in turn, heated to a temp. of the softening point or more of said sheet to eliminate the rule grooves at the bent parts. CONSTITUTION:At first, a rule roll 2 is contacted with the surface of a synthetic sheet S under pressure at a temp. of the softening point or more of said sheet S to form groove shaped rules L1-L4 dividing a flap A and face plates B-E to be formed into a cylinder. In the next step. the flap A is bent at the rule L1 by the guide part 3' of a guide 3 and the groove 4' of a grooved wheel 4 while the face plates B-E are bent at each rulse L2-L4 along the surfaces of a mold material 5 and the face plate E is adhered to the flap A to form the cylinder. Succeedingly, said cylinder is heated at a temp. higher than the softening temp. of the sheet S and the recessed gaps G at the rule parts are restored to the state prior to forming the recessed parts and filled to obtain the objective cylinder free from gaps and having right angle bent parts K.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin cylinder, which forms a square cylinder by bending and bonding a synthetic resin sheet into a square shape. In order to manufacture a rectangular cylindrical body by folding a synthetic resin sheet, it is common to provide the sheet with bending lines in advance.

However, while it is necessary to make the creases deep to improve bendability, it is also necessary to make the creases as shallow as possible to improve the shape retention of the cylindrical body after bending, and it is necessary to fully satisfy both characteristics. is quite difficult.

The present invention solves this difficulty by eliminating the once-formed ruled grooves after bending, thereby achieving both bendability and shape retention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of implementing the present invention will be described below with reference to the drawings.

Figure 1 is a cross-sectional view of a synthetic resin sheet with ruled lines, Figures 2 to 7 are cross-sectional views showing the process of bending and gluing the sheet to form a cylinder, and Figure 8 is a square cylinder. FIG. 9 is a front view of the manufacturing apparatus, and FIG. 10 is a plan view thereof.

The figure shows an example of forming a square cylinder, in which a thermoplastic synthetic resin sheet (e.g., a single or composite sheet of polyvinyl chloride, polycarbonate, polystyrene, polypropylene, polyester, etc.) 8 is used to form a rectangular tube. Do as follows. The apparatus is illustrated in FIGS. 9 and 10, and the sheets 1-8 are fed out from the sheet row n1 and processed.

First, as shown in Fig. 1, C) S has a groove-shaped ruled line that demarcates the margin A and the face plates B, O, l), and E, which form a square tube.
L2. L3. L, is provided. The ruled lines are formed by pressing the ruled line roll 2 against the sheet surface at a temperature below the softening temperature of the sheet S to form grooves having a V-shaped cross section or a U-shaped cross section. The depth is preferably 0 to 70% of the thickness of the sheet s. Since these ruled lines are formed at low temperatures, they have the property of returning to their original flat state when heated.

Next, each of the tubes is bent from the above-mentioned ruled lines to form a rectangular tube. In this embodiment, first, the adhesion margin A is between the acute-angled guide portion 3' of the guide plate 3 and the groove 4 of the groove wheel 4, as shown in FIG.
′ to create a crease, and use to bend it into an acute angle. Then, the face plate B, which becomes a square tube, is 0. D and F are folded along the surface of the mold 5. For example, face plate 0. D as shown in Figure 3 with a bending roll 6.7
Then, as shown in FIG. 4, the face plate E is bent 90 degrees along the ruled line LA and pressed onto both sides of the molded material 5, and then the face plate E is bent 90 degrees along the ruled line L4 with the bending roll 8 as shown in FIG. D and E are made into a U-shape, and as shown in FIG. 5, the face plate B is bent about 90' along the ruled line L2 using the bending roll 9 to form the face plate B, 0. Make D and E into square cylinders.

Note that the adhesive margin A may be bent when the face plate is bent as shown in FIG. 3 or 4.

Next, as shown in FIG.
7, place the face plate B on the roll 1, apply adhesive with the adhesive nozzle 11, and place the face plate B on the roll 1 as shown in
2, press it against the mold material 5, overlap the adhesive margin A with the face plate E,
It is pressed by the roll 13 to adhere to the face plate E. In this example, since the margin A was raised from an acute angle, it tends to return to the bent state due to elasticity and press against the face plate E. Therefore, no force is exerted in the direction away from the face plate E, and therefore there is no pressing force. However, if it is pressed by the roll 13, the adhesion will be even better.

The rectangular cylinder formed by bending and adhering in this way is heated to a temperature higher than the softening temperature of the sheet S using hot air, heated rolls, or other suitable heat source Q to restore the shape of the bent part and shape it. , this shaped rectangular cylinder is taken up by a conveyor 14.

When a sheet is bent along a ruled line as described above, the ruled line forms a V-shaped gap G on the inside of the folded part as shown in Figure 8I, and the thickness of the sheet is partially thin, so if it is not The strength is poor and the cylinder body becomes stiff and easily loses its shape, but if it is heated to a temperature higher than the softening temperature of C) 8, the above gap G will be restored to the state before the recess was formed and will be filled. As shown in Figure 8 (■), the bent part K becomes a right-angled bent part K with no gaps, so its strength is restored and the waist is strengthened, which not only prevents the shape from deforming, but also
There is an advantage that the whitening will disappear even if it becomes white when bent.

The present invention involves bending a synthetic resin sheet along ruled lines to form a cylindrical body as shown in E-E below, and heating the sheet above the softening temperature of the sheet to restore and fill the gap between the folds and restore its strength. Since the stiffness is strengthened and shape deformation can be prevented, a cylindrical body with excellent dimensional accuracy and excellent quality can be obtained.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention; FIG. 1 is a cross-sectional view of a synthetic resin sheet provided with ruled lines, and FIGS. 2 to 7 show the process of bending and gluing the sheet to form a cylinder. 8 is an enlarged cross-sectional view showing the bent part of the rectangular tube, FIG. 9 is a front view of the manufacturing equipment, and FIG. 10 is a plan view as well.S is a synthetic resin sheet, A is a gluing area. ,B,0゜1〕,E
is the face plate, Ll + L2 + 5% + L4 is the ruled line, Q
is a heat source, 1 is a sheet roll, 2 is a ruling roll, 3 is a guide plate, 4 is a groove wheel, 5 is a shape material, 6, 7, 8.9 are rolls for folding, 10 is a raising plate, 11 is an adhesive nozzle h12113
Hall, ” is a conveyor. 1st time 6 8th door 51 舊 1 Zufu 7b I 113

Claims (1)

[Claims] 1. Heat and press the ruled lines that define each face plate and gluing margin on a synthetic resin sheet at a temperature lower than the softening temperature of the sheet to form four grooves, and then fold the sheet along the ruled lines. 1. A method for manufacturing a synthetic resin cylindrical body, which comprises: forming a cylindrical body by heating the ruled line portion to a temperature higher than the softening temperature of the sheet to fill indented gaps in the ruled line portion.