JPH01170525A - Manufacture of flanged blow product - Google Patents

Abstract

PURPOSE:To prevent a flange thickness from becoming thin and to remove residual air by clamping and folding a parison on its outside, molding an outward-opening edge and press-molding a flange between a split die and an ascending mandrel. CONSTITUTION:When the parison P is supplied and descended from a die 1, the lowermost end hangs under the peripheral end of the press surface 8 of a mandrel 5 and arrives at a prescribed point, clamping jaws 4a, 4b are advanced by the operation of cylinders 3a, 3b to clamp and break the parison. Then, the clamping jaws 4a, 4b are retreated by the retreating operation of a cylinder and split dies 2a, 2b are closed. The upper half of the upper edge H made by clamping and breaking are put into the split die. The lower half of the lower die and a lower edge J are extruded as they are, as soon as a projection part 6 enters the split die by the ascent of the mandrel 5, the pressed surface 8 is pressed to form a flange F as it approaches and faces recess parts 7a, 7b for forming a flange. A blow product is formed in the split die.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for forming flanged blow products.

Problems to be Solved by the Invention> The applicant has already proposed a molding device for blow products with flanges in Japanese Utility Model Application Publication No. 107220/1989, but this device does not allow molding of parisons under an open/close split mold. It expands outward from the inside using air pressure, and this expanded part is pressed during mold clamping.
There is a problem that the parison is stretched during the expansion process and its wall thickness becomes thinner, and there is also a problem that air remains inside when the flange is pressed. Furthermore, since the flange thickness is obtained by expanding the parison outward, there is a problem in that it is not possible to mold a flange having a diameter smaller than the diameter of the parison. Furthermore, there was a problem in that the thickness of the flange could not be adjusted at all.

The present invention attempts to solve these problems.

<Structure of the Invention> The present invention provides a split mold in which an outer open edge of one to several layers is formed by pinch-folding from the outside under an open/close split mold for a parison that is fed out and lowered, and the outer open edge is closed for blow molding. A method for producing a flange-equipped blow product, characterized in that the flange is press-formed between the flange and a mandrill that moves upward.

<Example> Examples will be described below based on the drawings.

Place the open/close split molds 2a and 2b under the die l. Split mold 2
Clamps 4a and 4b which move forward and backward independently of the split molds are attached to the lower surfaces of the molds a and 2b by means of cylinder devices 3a and 3b. Reference numeral 5 is a mandrill that moves up and down, and has a protrusion 6 that enters between the split molds and a press surface 8 that faces the flange forming recesses 7a and 7b of the split molds.

The parison P is fed out and lowered from the die 1 according to the usual method, and when the lower end hangs out below the circumferential edge of the press surface 8 of the mandrill 5 and reaches a predetermined point, the cylinders 3a and 3b are actuated to release the clamps 4a and 4b. The parison P is moved forward, and the hanging part of the parison P is pinched from the outside and folded into a cross-sectional shape. Since the lower end of the parison P is successively pulled up during the pinch-folding process, the wall thickness does not become thinner at all. When the pinch folding is completed, use the pinch tool 4a.
, 4b are moved back by the backward movement of the cylinder, and then the split mold 2a is removed.

It operates by closing 2b. The upper half of the upper edge H created by the sandwich folding enters the split mold, and the lower half and the lower edge J are exposed as they are, and at the same time as the protrusion 6 enters between the split molds due to the upward movement of the mandrill 5, the press surface 8 is the flange forming recess 7g
, 7b, the recess 7a, ? The flange F is formed by pressing into the inside of b.

A blow product B is molded in the split mold. Note that the extra wall on the outside of the flange F is cut between the recess and the circumferential edge of the press surface.

FIG. 7 shows an example of forming a flange having a smaller diameter than the descending parison P having a large diameter. The recesses 7a and 7b for forming flanges provided under the split molds are deepened to increase the exposed portion of the upper edge H, increasing the thickness of the flange F, and the outer surface of the press surface 8 of the mandrill 5 is Closed split recess 7a
, 7b in contact with the outer periphery of the paper, and in the process cut off the excess material on the lower edge J of the pinch-fold.

In addition, in FIG. 8, the diameter of the flange forming recesses 7a and 7b is made larger than the diameter of the press surface 8, and a pinch-off 8a is provided on the outer periphery of the press surface 8, so that the excess material under the lower edge H of the pinch-fold is removed from the flange. This shows an embodiment in which the cutting is performed within the forming recesses 7a and 7b, allowing for more precise molding with a thickness of 7 langes.

FIG. 9 shows an embodiment for increasing the thickness of the flange F,
Using the upper and lower scissors 4a and 4b, fold the parison P between four layers, and press the top three layers between the recesses 7a and 7b and the press surface 8, assuming that the upper layer will fit inside the split mold. It is possible to form a flange F with increased thickness.

In FIG. 10, a punching protrusion 8b is provided on the press surface 8 so that a hole is punched when forming the flange F.

FIG. 11 shows an example in which a recess 9 for forming a flange is provided on the press surface 8 of the mandrill 5, and a pinch-off 8a is provided on the outer periphery of the recess 9. In this example, the bottom surface of the open/close split mold becomes flat and forms the press surface.

<Effects of the Invention> As described above, in blow molding, the parison descending below the split mold is held open from the outside before closing the split mold, and the lower edge of the parison is folded from the outside. Since the flange is pressed between the split mold and the mandrill that moves upward, the flange does not become thin, there is no residual air, and the thickness can be freely adjusted. Furthermore, since it is possible to form a flange with a smaller diameter than the parison diameter, there is an effect that the design of flanged blow products can be completely renewed.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing the first embodiment in a state where it is lowered under the split mold of the parison, Fig. 2 is a longitudinal sectional view showing the same in the state of pinching and folding, and Fig. 3 is an enlarged view of the scissors. 4 is a plan view of the cross-shaped clamping operation, FIG. 5 is a vertical cross-sectional view of the mold clamping state, FIG. 6 is a vertical cross-sectional view of the mandrill in its upward movement state, and FIG. A vertical cross-sectional view of the second embodiment during mold clamping and flange forming, FIG. 8 is the same, a vertical cross-sectional view of the third example, and FIG.
The figure is a longitudinal cross-sectional view showing the fourth embodiment in a sandwiched state;
Figure 0 is a vertical cross-sectional view showing an example of the hole drilling of the flange, Figure 11 is an example view showing the other side of flange forming, 1 is a die, 2a
, 2b is an open/close split type, 3a and 3b are cylinder devices,
4a, 4b are clippers, 5 is a mandrill, 6 is a protrusion, 7
a, 7b is a recess for forming a flange, 8 is a press surface, 8a
Reference numeral 8b indicates a pinch-off, numeral 8b indicates a drilling protrusion, and numeral 9 indicates four parts for forming a flange.

Claims (1)

[Claims] (1) One layer to several layers of outer edges are formed by pinch-folding from the outside under the opening/closing split mold of the parison that is fed out and lowered, and the split mold and the mandrill that move upward are used to close the outer edges for blow molding. A method for producing a flanged blow product characterized by press-forming it into a flange between.