JP2552642B2 - Vehicle headrest frame molding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a frame of a headrest mounted on a vehicle seat such as an automobile seat.

[0002]

2. Description of the Related Art As a conventional method of molding a headrest frame, a method disclosed in Japanese Patent Publication No. 3-11889 is known. As shown in FIG. 5, first, a thermoplastic plastic material is extruded into a tubular shape by an extrusion molding machine (not shown), and the extruded parison P is sandwiched by a part of the die 10 to seal it. Then, compressed air is blown into the parison P to expand the parison P, and the parison P is expanded so as to be in close contact with the inner wall of the mold 10 to form the hollow frame 3. This method is a usual blow molding and is a known technique.
During this blow molding, thin recesses 3a on both sides of the frame 3,
3a is formed. By forming the convex portions 10a, 10a in the cavity of one mold 10, the concave portions 3a,
3a can be easily formed. In this way,
Blow molding of only the hollow frame 3 having a desired shape can be completely automated. When the parison P is expanded and cooled to some extent, the mold 10 is opened and the molded frame 3 is sent out onto the conveyor 11. During the transportation, cold air A is blown onto the frame 3 to accelerate the cooling of the resin. The frames 3 are aligned near the end of the conveyor 11, and a heater 12 such as a welder is pressed against the predetermined positions on both sides of the frame 3 in a stationary state from above to accurately form the intervals between the recesses 3a and 3a. Therefore, the conveyor 11 employs an intermittent motion. The steps up to this point can be made unmanned, and the frame 3 having the concave portions 3a, 3a, which are accurately kept at a constant interval on both sides, can be formed in large quantities, quickly, and under full automation. Then, the base ends of the two stays 1 and 2 are set in the recesses 3a and 3a of the frame 3 while the recesses 3a and 3a of the frame 3 are not yet cooled, and the base 3 has a property of being fused with the resin of the frame 3 (frame 3). The same resin as is preferred) Preheat (180
The base ends of the stays 1 and 2 are covered with resin plates 4 and 4 that have been heated at a temperature of ℃ to 250 ℃. Subsequently, the resin plates 4 and 4 are heated and pressed by the mold 13 provided with the pins 14 and 14 which are set to be slightly wider than the diameters of the stays 1 and 2, and at the same time the gas B is introduced into the frame 3.
Blow in. Details of the heating and pressurization and the blowing of the gas B are as shown in FIG. 6. The pin 14 serves to position the stays 1 and 2, and the stays 1 and 2 are firmly fixed, and the mold 13 is made of resin. Heat and press the plate 4,
In opposition to this pressure, the gas B increases the internal pressure in the frame 3.

[0003]

According to the conventional method, the heater 12 heats the recesses 3a, 3a, uses the resin plates 4, 4, blows the gas B into the frame 3 and the resin plates 4, 4.
Since it requires a step of heating and pressurizing, it is disadvantageous in terms of cost reduction.

Therefore, an object of the present invention is to provide a method for molding a frame for a vehicle headrest, which can further reduce the cost.

[0005]

In order to achieve the above-mentioned object, the present invention comprises a step of blow-molding only a hollow frame having a desired shape with a plastic material, and at the time of this blow-molding, a frame is formed on both sides of one side of the frame. A step of forming two or more recesses so that the internal space is approximately the thickness of the stay, and forming a bulge portion that is cut into both sides of the lower part of the frame or substantially the entire length of the lower part to serve as an insertion port; and blow molding The step of cutting the bulged portion of the cooled frame to form an insertion opening, and inserting the stay into the frame from the insertion opening to form the stay on the inner surface of the recess and the other surface on which the recess of the frame is not formed Step of contacting or very close to the inner surface of the step, and step of pressing the concave portion of the frame and the portion facing the concave portion against the stay and fixing the stay to the claim by ultrasonic welding or the like , And it has a.

[0006]

[Function] By blow-molding only the hollow frame having the desired shape, a large amount of hollow molded products can be automated and unmanned in a short time, and the stay is easily and quickly fixed to the frame. This can be done and a significant cost reduction can be achieved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view taken along the line AA of FIG. 2. When the frame 3 is blow-molded, the inner space is formed on both sides of one side of the frame 3 so as to have a thickness of the stays 1 and 2. To form two or more recesses 5 and 5, respectively,
A bulged portion 7 (see FIGS. 3 and 4) is formed by cutting both sides or the lower portion of the frame 3 into substantially the entire length and serving as an insertion opening 6. The frame 3 having such recesses 5 and 5 (two recesses 5 and 5 are also formed on one side) is formed by extruding a thermoplastic plastic material into a tubular shape by an extruder (not shown) as in the conventional case. , The extruded parison P is sandwiched by a part of the mold 10 to be sealed, and then compressed air is blown into the parison P to expand the parison P, and the parison P is expanded so as to be closely attached to the inner wall of the mold 10. The frame 3 is molded. At this time, a convex portion (not shown) for forming the concave portion 5 is formed in the cavity of the mold 10. That is,
The first step in the frame molding method of the present invention is a step of blow molding only the hollow frame 3 having a desired shape with a plastic material. At this time, two or more recesses 5 and 5 are formed on both sides of one side of the frame 3, respectively. It is a step of forming the bulging portion 7 which becomes the insertion opening 6 by being formed and being cut into substantially the entire length of both sides or the lower portion of the frame 3. In recent blow molding technology, the wall thickness of the parison P can be partially changed. It is preferable that the thickness of the portions of the stays 1 and 2 inserted into the frame 3 that come into contact with or come very close to the recesses 5 and 5 of the frame 3 be thicker than the thickness of other portions. After the blow-molded and cooled bulging portion 7 of the frame 3 is cut to form the insertion opening 6, the stays 1 and 2 are inserted into the frame 3 through the insertion opening 6 and the stays 1 and 2 are recessed. , 5 and the inner surface of one side of the frame 3 on which the recess 5 is not formed are brought into contact with or very close to. At this time, it is preferable to keep the interval between the stays 1 and 2 constant. If the dimensions of the insertion opening 6 are correct, the stays 1 and 2 can be positioned simply by inserting the stays 1 and 2. Stays 1 and 2 are shown in Figure 1.
Although only one stay 1 is shown in FIG. 2, it is similarly set on one side of the frame 3. In FIG. 1, a stay 1 has a two-layer structure in which a resin pipe 1B is coated on the outer circumference of a metal pipe 1A. The concave portion 5 farther from the lower portion of the frame 3 is deeper on the inner side of the frame 3.
A, the protrusion 5B forming the deep recess 5A plays a role of reinforcing the hollow frame 3. Frame 3
The concave portion 5 and the portion facing the concave portion 5 are pressed against the stays 1 and 2, and fixed by means of ultrasonic welding or the like.

Another embodiment shown in FIG. 3 shows an example in which a protrusion 8 protruding outward is formed at a portion of the stay 1 or 2 which comes into contact with or comes very close to the recess 5 on the upper side of the frame 3.
By providing such protrusions 8, the stays 1 and 2 after ultrasonic welding are firmly fixed to the frame 3.

Still another embodiment shown in FIG. 4 is a stay 1
As an example, a U-shaped member is used as the above, and the recess 5 formed above the lower part of the frame 3 is formed small so that the deep recess 5A and the protrusion 5B do not correspond to the location of this recess 5 during blow molding. It shows an example in which they are formed at separate positions.

The stays 1 and 2 are not limited to those having a two-layer structure of a metal pipe 1A and a resin pipe 1B, but may be a metal pipe or a solid rod-shaped member.

[0012]

As described above, according to the present invention, a recess having a predetermined shape can be formed at the time of blow molding, and only a hollow frame can be mass-produced in a short time. This process is automated and unmanned. Therefore, the number of subsequent steps is small and the cost can be significantly reduced. That is, after blow molding a frame in which a recess having a predetermined shape is formed, the bulging portion is cut to form an insertion port, a stay is inserted from this insertion port, and the frame and the stay are ultrasonically welded at the recess. Therefore, the frame of the vehicle headrest can be molded easily and quickly. Further, in the case where the protrusion protruding outward is formed in the portion of the stay that comes into contact with or is extremely close to the concave portion of the frame, the fixation between the frame and the stay becomes even stronger. Further, in the case where the recess farther from the lower portion of the frame has a deep recess toward the inner side of the frame, the strength of the frame can be increased by forming the deep recess.

[Brief description of drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 2 showing a preferred embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view.

FIG. 3 is a plan view showing another embodiment.

FIG. 4 is a plan view showing still another embodiment.

FIG. 5 is a diagram illustrating a molding method of a conventional example.

FIG. 6 is an enlarged cross-sectional view of a stay fixing portion of a conventional example.

[Explanation of symbols]

 1, 2 Stay 3 Frame 5 Recess 6 Insertion port 7 Bulging part 10 Mold P Parison

Claims (3)

(57) [Claims] 1. A step of blow-molding only a hollow frame having a desired shape with a plastic material, and two or more each of which is such that the internal space is approximately the thickness of the stay on both sides of one side of the frame during this blow-molding. Forming the concave part of the frame and forming a bulge part that is cut into almost the entire length of the lower part of the frame or the lower part of the frame to form a bulge part, and cutting the bulge part of the frame that has been blow molded and cooled to open the insert port. A step of forming the stay, a step of inserting the stay into the frame through the insertion opening to bring the stay into contact with or in close proximity to the inner surface of the recess and the inner surface of the other surface of the frame where the recess is not formed, and the recessed portion of the frame A step of pressing the stay and the portion facing the recess to the stay and fixing the stay to the claim by ultrasonic welding or the like. Over-time molding process. 2. The method of molding a frame for a vehicle headrest according to claim 1, wherein a protrusion that protrudes outward is formed at a portion of the stay frame that comes into contact with or comes very close to the recess of the frame. 3. The recess farther from the lower portion of the frame forms a deep recess closer to the inner side of the frame.
The frame molding method for a vehicle headrest according to item 2 or 3.