JPS594297B2 - Saddle and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a saddle for a bicycle, motorcycle, etc., and a manufacturing method that can produce the saddle with high efficiency.

Conventionally, as a general method for manufacturing saddles, a saddle base is formed by injection molding polyamide resin, polypropylene resin, etc., and a skin made of soft urethane foam or polyethylene foam cut into an appropriate shape is laminated to the soil of this saddle base. Furthermore, there was a method of covering the entire outer surface with vinyl chloride resin leather cut into an appropriate shape and fixing one end of the covered leather with wire at the bottom of the saddle.
Most of these operations are done by hand, which requires skill and is inefficient, and requires time and effort as the skin and leather are cut separately, which is a major factor in increasing the cost of the product.

In addition, as a conventional and somewhat special manufacturing method, a saddle is formed by vacuum forming a composite sheet in which a soft polyvinyl chloride sheet is laminated to a sheet made of polyethylene or low-expanded polyethylene foam, with the vinyl sheet serving as the outer surface. ,
There is a method of trimming the edges of the composite sheet that protrude from the mold during vacuum forming to produce a product.

However, this method has the disadvantage that it is limited to children's saddles because it is not strong enough for a saddle that supports the weight of a human, and it is also necessary to trim the entire relatively thick composite layer. Therefore, this trimming not only causes material loss but also requires skilled manual labor for trimming, which is inefficient.The present invention provides a saddle and The present invention provides a method for producing the same.

To explain the present invention in detail, as a first invention, an independent pore foam sheet made of a soft synthetic resin or rubber has open pores exposed on at least one side of a surface material made of a flexible sheet-like material. The saddle-based independent porosity is formed by bonding a composite sheet such that the surface where the open pores are exposed is located on the side that contacts the hard synthetic resin, and the surface material is the outer surface. A second aspect of the present invention relates to a saddle formed by integrally injection molding a base made of a hard synthetic resin on the surface of a foam sheet, and a surface material made of a flexible sheet has open pores on at least one side on one side. A composite sheet is formed by adhering an exposed closed-porous foam sheet made of soft synthetic resin or rubber so that the surface with exposed pores is located on the side that contacts the hard synthetic resin, and the surface material is outside the composite sheet. A saddle is formed by vacuum forming the saddle main body, and a hard synthetic resin injection molding material is injected into the mold into which the saddle main body is fitted to form a base body integrally with the independent porous foam sheet of the saddle main body. This relates to a manufacturing method for a featured saddle.

In the present invention, the surface material 1 is made of a flexible sheet-like material, and examples thereof include sheets made of soft polyvinyl chloride resin, ethylene vinyl acetate resin, synthetic rubber, etc., and sheet materials such as thermoplastic synthetic resin leather. Applicable.

As the independent porous foam sheet 2 made of soft synthetic resin or rubber that is adhered to the surface material 1, a sheet material having open pores exposed on its surface is used.

The material used is, for example, polyurethane foam, polyethylene foam, natural or synthetic rubber sponge, or the like with closed pores.

By slicing the closed-porous foam GJ into sheets, one open pore is exposed on the surface thereof.

The closed pore foam sheet 2 made of soft synthetic resin or rubber is required to be a material with good resilience against pressing force.

Appropriate means can be used to bond the surface material 1 and the independent porous foam sheet 2 made of soft synthetic resin or rubber to obtain the composite sheet 3. Either or both of the porous foam sheets 2 may be bonded to each other with an adhesive applied thereto, or if the surface material 1 is a thermoplastic synthetic resin such as polyvinyl chloride, the sheets may be formed using a molding machine such as a calendar. When the surface material 1 itself is still hot immediately after being formed into a shape and has adhesive properties, it may be bonded together with a separate porous foam sheet 2 made of a soft synthetic resin or rubber prepared separately. good.

The composite sheet 3 thus obtained is formed into a saddle main body 8 having a saddle shape.

Vacuum forming is preferable as this forming method due to the characteristics of the saddle shape.

In this vacuum forming method, for example, as shown in FIG. 1, a mold 5 having a large number of vacuum suction holes 4 is prepared, the laminated sheet 3 is stretched above the mold 5, and heating means such as an electric heater is used. 6, the composite sheet 3 is brought into contact with the periphery of the opening 1 of the mold 5 to close the opening γ, and suction is applied through the suction hole 4, thereby applying the composite sheet 3 to the inner wall surface of the mold 5. The saddle main body 8 is formed by applying the resin as shown in the figure.

When thermoplastic synthetic resin leather is used as the material for the surface material 1 and is vacuum-formed, the base fabric for the leather may be a well-stretched knitted fabric or a fabric made of stretchable fibers such as spandex. If elastic fabric is applied,
Since the plastic deformation of the leather is not inhibited during suction during vacuum forming, it adheres well to the inner wall surface of the deep mold 5, and it is possible to form the saddle main body 8 into an accurate shape by vacuum forming.

The molded saddle main body 8 is fitted into a mold 5a in order to integrally injection mold a hard base body 9.

As this mold 5, the mold 5 used for molding the saddle main body 8 in the previous step, for example, vacuum molding, can be used as is.

In this case, there is no need to refit the molded saddle main body 8 into the injection mold 5a, so there is no fear of misalignment during refitting, and the refitting work can be omitted.

After the saddle main body 8 is molded in this way, the molded saddle main body 8 is removed from the mold 5 and fitted into a separately prepared injection mold 5a, or the mold 5 is fitted into the injection mold 5a without removing the mold. The molds 5, 5a and the sealing mold were converted into an injection mold, and the injection molding sealing mold 10 was fitted to the open lower part of the mold 5.5a, and the injection gate 11 provided in the sealing mold 10 was fitted. A rigid thermoplastic synthetic resin injection molding material is injected and filled into the molding gap formed by the molding machine 10 using an injection molding machine 13 .

Examples of the injection molding material include polypropylene resin, medium- or low-pressure polyethylene resin, and polyamide resin.

Among these, polyamide resins are prone to distortion and warping due to internal stress, so to prevent this, it is preferable to anil (immerse in hot water).

In addition, the polypropylene resin on the upper side does not require anil (warm water immersion) due to the required physical properties of the saddle, and has strong strength.
Since it has a light specific gravity of 0.9, it is particularly suitable as a saddle material.

The injection gate 11 for injecting the injection molding material may have not only one hole but also multiple holes as shown in FIG. 4.

The shape of the opening in the mold of the gate 11 is not circular as shown in FIGS. 5a and 5b, but may be a flat shape such as an oblong or rectangular shape.

In this way, when the injection gate 11 is porous or the shape of the opening in the mold is flat, the injection pressure during sub-injection molding is dispersed and averaged within the mold. Prevents the independent porous foam sheet 2 made of soft synthetic resin or rubber located inside the saddle main body 8 fitted in the molds 5, 5a from being partially depressed by injection pressure to form a concave portion 12. can.

When the injection gate 11 is provided in the sealing mold 10 at a position perpendicular to the saddle main body 8 fitted in the molds 5 and 5a as shown in FIG. 9, the injection pressure is directly applied to a part of the saddle main body 8. Since it is easy to form a partial recess 12 in the independent porous foam sheet 2 made of soft synthetic resin or rubber facing inward of the saddle main body 8, the injection direction from the gate 11 is directed against the saddle main body 8. If the gate 11 is provided diagonally from the end of the sealing mold 10 as shown in FIG. 3 so as not to form a right angle, the injected material will flow through the independent pores of the saddle main body 8 made of soft synthetic resin or rubber. Since the flow sweeps over the surface of the elastic foam sheet 2, the formation of recesses 12 as shown in FIG. 9 can be avoided.

The gate 11 provided in the diagonal direction as described above can be formed by forming the opening in the mold into a flat shape such as an elongated oval shape or a rectangular shape as described above. Formation of depressions in the porous foam sheet 2 can be prevented.

If the injection gate 11 is provided at the mating edge of the molds 5, 5a and the sealing mold 10 as shown in FIG. 6, the molds 5.5a and the sealing mold 10 are separated and the molded saddle is demolded. At this time, it is easy to remove the injection material stuck in the injection gate 11.

In the present invention, a composite sheet in which a surface material and a closed-porous foam sheet made of soft synthetic resin or rubber are laminated together and a hard substrate are integrally formed with each other by injection molding of the hard substrate. This eliminates the need for troublesome manual work such as tying the ends of the surface material with wire at the bottom of the saddle, and the manufacturing efficiency is high, making it possible to reduce product costs. Since the molding material is directly injected onto the surface of the closed-porous foam sheet made of soft synthetic resin or rubber that constitutes the inside of the main body of the saddle, the injected molding material penetrates into the exposed air bubbles on the surface of the closed-porous foam sheet. Both can be integrally combined more firmly.

The outer surface of the saddle is made of a composite sheet made by adhering a flexible sheet-like surface material and a closed-porous foam sheet made of soft synthetic resin or rubber to one side, providing cushioning properties for the human body. In addition to being of good quality, a hard base is provided on the inside or underside, so it is durable and will not break even when a person's weight is applied to it.

Furthermore, the saddle of the present invention can be used as a saddle for bicycles, motorcycles, etc. not only for children but also for adults.

In addition, a hard substrate is formed on the inside or underside of the main body of the saddle, which is formed from a composite sheet made by adhering a surface material made of a flexible sheet-like material and a closed-porous foam sheet made of soft synthetic resin or rubber to one side of the surface material. Since it is integrally formed by injection molding, even if trimming is required, only the parts of the main body of the saddle that are unnecessary for the product need to be trimmed, reducing material loss due to trimming, and making it thicker than the overall thickness. Since the trimming operation is easy, the cost can be reduced.

Furthermore, if such trimming work is required, the unnecessary parts of the saddle body can be trimmed after the hard base body is bonded to the saddle body body by injection molding. Using the shape of the base as a guide, trimming mainly the saddle is easy and does not require any skill.

Furthermore, since an independent pore foam sheet is used, even if a hard synthetic resin injection molding material is injected, the injection molding material will impregnate into the open pores and impair the cushioning properties, unlike in the case of an open pore foam sheet. There is no need to provide a layer to prevent penetration of injection molding materials, and even if the surface material is damaged when molded into a saddle, water etc. will not penetrate.
This is preferable.

Next, examples of the present invention will be shown.

Example While the polyvinyl chloride sheet formed by the calender was still hot, a closed-porous polyethylene foam sheet sliced on both sides was attached to one side of the polyvinyl chloride sheet due to the self-adhesive properties of the polyvinyl chloride sheet. A laminated composite sheet is formed.

The thickness of the polyvinyl chloride sheet in this composite sheet is 0.4 to 0.8 mm, and the thickness of the closed pore polyethylene foam sheet is 5 mm, so the total thickness of this composite sheet is 5.4 to 5.8 m. be.

This composite sheet was stretched above the opening of a vacuum forming mold with a saddle shape engraved on the inner wall so that the polyvinyl chloride sheet side of the composite sheet faced the mold, and the temperature was raised to 160°C on the composite sheet surface. This composite sheet is brought into contact with the opening of the vacuum forming mold to close the opening.

Next, suction is applied by a vacuum suction machine through multiple suction holes drilled in the vacuum forming mold, the sheet is brought into close contact with the inner wall surface of the vacuum forming mold, and the heat of the sheet is conducted and diffused into the mold to cool it. The sheet is then molded to match the shape of the inner wall surface of the mold.

Next, a closed mold for injection molding is matched with the opening of the vacuum mold that holds the vacuum-formed saddle main body as it is, and both molds form a cavity filled with injection molding material.

The sealing mold is provided with an injection gate, the opening of the gate facing the filling gap is rectangular, and the longitudinal edge of this rectangular shape is located inside the saddle main body fitted in the vacuum forming mold. The plane of the closed-cell polyethylene foam sheet extends parallel to the direction in which it extends.

The gate also penetrates diagonally from the end of the sealing mold into the filling cavity.

From this injection gate, 20 to 3 times
Injection and filling is performed with an injection pressure of 300 to 5001 crg/crit with a 0 second shot.

The molding material filling the filling space penetrates into the air bubbles exposed on the surface of the closed-cell polyethylene foam sheet in the saddle body, forming a polypropylene-infiltrated composite layer on the surface of the sheet, and bonding the two well.

The injected polypropylene resin loses heat and solidifies, leaving a layer of 3 to 3 mm thick on the surface of the closed-cell polyethylene foam sheet.
A rigid substrate is formed in layers of 5 m/m.

The saddle, in which the base body and the saddle main body are integrally bonded, is removed from the mold, and if any edge portions of the composite sheet that protrude from the mold during vacuum forming remain, they are trimmed.

The bicycle saddle thus formed was strong and durable enough to be used as a saddle for not only children's bicycles but also adult bicycles.

In addition, the closed-porous polyethylene foam sheet has excellent recovery properties, and the injection gate has a rectangular opening shape for the filled voids and extends in the longitudinal direction parallel to the plane formed by the closed-porous polyethylene foam sheet. The sealing mold penetrates diagonally through the end of the sealing mold provided, so that no depressions are formed in the closed-porous polyethylene foam sheet due to injection pressure, and - excellent cushioning properties are achieved on average in any part of the saddle. Be prepared, and
Since the polypropylene resin is injected at 190-200°C and integrated with the closed-cell polyethylene foam sheet,
The excellent restorability of the foam sheet was not impaired in any way.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams showing each step of implementing the manufacturing method of the present invention, FIGS. 4 and 6 are explanatory diagrams of steps according to another embodiment of the manufacturing method of the present invention, and FIG. 5a , t) are both plan views showing examples of the opening shape facing the mold inner wall surface of the injection gate, and FIG. 1 is a perspective view of an example of the saddle of the present invention.
FIG. 8 is a sectional view taken along the line A--A in FIG. 1, and FIG. 9 is an explanatory diagram of steps in a comparative example compared to the embodiment of the present invention. 1... Surface material, 2... Independently porous foam sheet made of soft synthetic resin or rubber, 3...
...Composite sheet, 4...Suction JL, 5,5a.
...Mold, 1...Opening, 8...
...Saddle main body, 9...Hard base, 10...
...Injection mold sealing mold, 11...Injection gate.

Claims (1)

[Scope of Claims] 1. A closed-porous foam sheet made of a soft synthetic resin or rubber with open pores exposed on at least one side is attached to one side of a surface material made of a flexible sheet-like material. A composite sheet is bonded so that the exposed surface is located on the side that contacts the hard synthetic resin. A saddle made by integrally injection molding a base made of synthetic resin. 2. A closed-porous foam sheet made of a soft synthetic resin or rubber with open pores exposed on at least one side is placed on one side of a surface material made of a flexible sheet-like material, and the open pores are exposed on one side. A saddle body is formed by vacuum forming a composite sheet that is glued on the side that contacts the hard synthetic resin so that the surface material becomes the outer surface, and the hard synthetic resin is injected into the mold in which the saddle body is fitted. A method for manufacturing a saddle, which comprises injecting a molding material to mold a base body integrally with the independent porous foam sheet mainly consisting of the saddle.