JPH05296469A - Leg of frame for 'kotatsu' foot warmer for household use - Google Patents

Abstract

PURPOSE:To make it possible to remove the leg main body from a die easily by a method wherein the leg main body with an even thickness for the whole body is formed integrally and with a hollow chamber inside by a gas injection into an uncured resin during an injection molding. CONSTITUTION:The title leg is equipped with a leg main body 1 made of a resin with a hollow chamber 8, a cushion 2 to bear a top plate, and a metal nut member 3. The leg main body 1 is integrally formed by a gas injection into an uncured resin so that the whole body may have an approximately even thickness. A blind hole part 7 and a plurality of grooves 9... which are radially connected to the blind hole part 7 are provided on a vertical wall part 5 of a recessed part 4 on the leg main body 1. Ribs 10... are formed on the hollow chamber 8 side by the walls which form the grooves 9.... The metal nut member 3 is embedded in the blind hole part 7 by press-fitting or insert molding at the time of injection molding. Since the blind hole part 7 is elastically deformed by the grooves 9..., and the diameter of which is easy to be extended, the metal nut member 3 can be easily pressfitted in the blind hole part 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leg for a home tattoo frame.

[0002]

2. Description of the Related Art Conventionally, a leg of a plastic home pallet frame is formed by adhering two members to each other so as to form a hollow structure. That is, one or both of the two members have a recess forming a hollow chamber, and the two members are bonded and integrated with each other so as to seal the recess.

[0003]

However, the leg of the conventional home tattoo frame as described above is disadvantageous in that the number of parts is large because it is composed of two members, and that a bonding work step is required. .. Further, in order to obtain a strong adhesive force and rigidity, it is necessary to form ribs or the like having adhesive surfaces that come into contact with each other, which causes a problem of increased weight.

Further, as shown in FIG. 12, the wall portion of the leg body a is slightly thicker in the vicinity of the corner k, but there is a drawback that shrinkage h, h occurs in the thickened portion. It was

Further, in order to attach the leg of the conventional home mantling frame to the main body of the mantling frame, it is necessary to fix it with bolts and nuts or the like, but it is possible to embed the nut in the hollow leg body. could not.

Therefore, the present invention solves the above problems,
It is an object of the present invention to provide a leg for a home tattoo frame which is light in weight and has a large rigidity and a large strength as well as no shrinkage at the corners and which can be easily manufactured.

Another object of the present invention is to provide a leg for a home tattoo frame, which can easily remove the leg body formed by injection molding by injecting gas into the uncured resin from the mold. To do.

[0008]

A leg of a home natura frame according to the present invention integrally and integrally forms a leg body having a substantially uniform wall thickness by injecting gas into an uncured resin during injection molding. It is formed so as to have a hollow chamber inside, and further, in the vertical wall portion near the upper end, a blind hole portion in the center and a plurality of radially connected groove portions are provided as recesses, and this groove portion is formed. A rib is formed on the hollow chamber side by a wall portion, and a metal nut member to which a mounting bolt for a home mantling frame is screwed is press-fitted or injected into the blind hole portion of the vertical wall portion. It is embedded by insert molding during molding.

In addition, the legs of the above-mentioned home tatami frame are tapered so that the leg body expands downward, and a small tubular body is integrally erected so as to project from the bottom wall into the hollow chamber. It is also preferable.

[0010]

The leg body can maintain a great rigidity and a great strength even if the wall thickness of the leg portion is made thin, and the weight can be reduced. Then, since the hollow chamber is formed inside by the gas injection into the uncured resin, in the injection molding process, the corner of the wall is pressed from the inside to the outside mold by the pressure of gas, The shape on the outer surface side of is accurate.

Further, when the metal nut member is press-fitted into the blind hole portion at the center of the vertical wall portion, the blind hole portion is elastically deformed by the plurality of groove portions around the blind hole portion, and the diameter is easily expanded. The member can be easily press-fitted. Then, the press-fitted metal nut member is prevented from coming off due to the restoring force due to the elastic deformation. Furthermore, the wall forming the groove reinforces the wall forming the blind hole.

When the leg body is injection molded,
Since the leg body has a tapered shape that expands downward, it is easy to remove the upper mold. Moreover, since a frictional force is generated between the small tubular body and the lower die forming the small tubular body, the leg body is held upright on the lower die.

[0013]

The present invention will be described in detail below with reference to the drawings showing the embodiments.

FIGS. 1, 2, and 3 show an embodiment of a leg of a home mantling frame according to the present invention. The leg L of the home mantling frame is a resin leg body 1 and A top plate receiving cushion 2 made of an elastic member such as resin or rubber attached to the wall 12 and a metal nut member 3 are provided.

The leg body 1 has a substantially rectangular column shape and is tapered so as to expand downward.

The leg body 1 is formed integrally with the hollow chamber 8 inside by injecting gas into the uncured resin during injection molding.

Any resin may be used as the resin for forming the leg body 1 as long as it is a thermoplastic resin, for example, polypropylene, polycarbonate, ABS, polystyrene, acrylic, or the like is preferable.

Further, a recess 4 on which the corner portion of the home tatami frame is placed is formed in a part of the upper end of the leg body 1.

That is, the recess 4 is composed of a rectangular vertical wall portion 5 hanging from the upper wall portion 12, and an isosceles triangular horizontal wall portion 6 continuous with the lower end of the vertical wall portion 5. The leg body 1 has a shape in which one corner at the upper end is cut out.

Next, as shown in FIG. 4, in the vertical wall portion 5 of the recess 4 of the leg body 1, the blind hole portion 7 in the center and the radial portion from the blind hole portion 7 are continuously formed by the above-mentioned gas injection molding. A plurality of groove portions 9 ... Are recessed. The blind hole portion 7 and the groove portion 9 communicate with each other.

Then, as shown in FIG. 5, the groove portions 9 ...
A rib 10 is formed on the side of the hollow chamber 8 of the leg body 1 by the wall forming the
... to form.

That is, the substantially cylindrical wall portion 11 forming the blind hole portion 7 projects toward the hollow chamber 8 side of the vertical wall portion 5, and further, around the wall portion 11 and the vertical wall portion 5, the above-mentioned Groove 9 ...
That form four triangle-shaped walls--that is, ribs 10 ...
─── are formed integrally.

As shown in FIG. 3, however, a bolt 16 for attaching to the home mantling frame A (shown in phantom) is screwed into the blind hole portion 7 of the vertical wall portion 5 of the leg body 1. The metal nut member 3 to be embedded is embedded by press fitting or insert molding at the time of the above injection molding.

The metal nut member 3 has a substantially cylindrical shape and has an internal thread portion on the inner cylinder portion.

In the illustrated example, the metal nut member 3 has a substantially cylindrical shape which is open on both sides, but it is also preferable to open this on only one side (see FIG. 10).

Next (returning to FIG. 3), the upper wall portion 12 of the leg body 1 is formed with a two-step blind hole 13 consisting of an upper blind hole portion 14 and a lower blind hole portion 15.

The upper blind hole portion 14 and the lower blind hole portion 15 are substantially circular in cross sectional shape.

Then, the substantially cylindrical top plate receiving cushion 2 is fitted into the upper blind hole portion 14, a screw such as a self-tapping screw is inserted into the cylinder, and the screw is inserted into the lower blind hole portion.
The top plate receiving cushion 2 is attached to the upper wall portion 12 of the leg body 1 by being screwed into the inside.

The leg body 1 has a substantially uniform thickness as a whole, and a hollow chamber 8 is formed inside thereof.

Then, from the bottom wall portion 17 of the leg body 1 to the hollow chamber 8
A small tubular body 18 is erected integrally so as to project into the inside.

That is, the small tubular body 18 projects into the hollow chamber 8 and has a cylindrical wall portion 19 whose base end portion is integrated with the bottom wall portion 17 of the leg body 1, and the cylindrical wall portion 19 of the cylindrical wall portion 19. The upper end includes a disk-shaped wall portion 20 having a lid shape.

In the present invention, the bottom wall portion 17 of the leg body 1 is used.
It is also possible to omit the small tubular body 18.

Further, in the upper wall portion 12, between the side in contact with the vertical wall portion 5 forming the recess 4 and the two-step blind hole 13,
A gas injection hole 37 for forming by gas injection is opened.

Next, as shown by the phantom line, a fitting recess 21 for fitting a portion above the horizontal wall portion 6 of the leg body 1 is formed in the corner portion C of the home rattling frame A. Has been done. A through hole 38 for inserting the cushion 2 is provided in the ceiling wall portion of the fitting recess 21.

Thus, while fitting the portion above the horizontal wall portion 6 forming the recess 4 of the leg body 1 into the fitting recess 21 of the above-mentioned home shatter frame A, the home shatter frame A The top plate receiving cushion 2 of the leg body 1 is inserted into the through hole 38 of the above so as to project upward.

Further, the mounting bolt 16 is inserted through the metal fittings 22 and 23 such as washers and spring washers into the fitting recess 21.
The mounting bolt 16 is screwed into the metal nut member 3 of the leg body 1 while passing through the hole 24 penetrating the peripheral wall of the leg body 1.

In this way, the leg L of the home mantling frame can be attached to the home mantling frame A.

If the top plate 39 is placed on the home pallet frame A in this installed state, the top plate receiving cushion 2 protruding upward receives the top plate 39, so that rattling or scratching occurs. Can be prevented.

Next, in the case of injection molding the legs of the home tatami frame of the present invention, as shown in FIGS. 6 and 7, an upper mold in which a hollow portion 25 having the same outer shape as the leg body 1 is formed. 26 and lower mold
Use 27.

Since the leg body 1 described above has a tapered shape that expands downward, the parting line P that is the boundary between the upper mold 26 and the lower mold 27 is located below the hollow portion 25. ..

Further, the upper die 26 is provided with a two-step cylindrical hanging piece 32 for forming the two-step blind hole 13.

Further, the upper mold 26 is provided with a resin injection passage 33 communicating with the hollow portion 25 and a gas injection passage 34 provided in the resin injection passage 33 and communicating with the hollow portion 25.

Further, the lower mold 27 is formed with a columnar vertical projection 35 for forming the small tubular body 18 of the leg body 1 described above.

Next, as shown in FIGS. 6 and 8, the upper mold 26 is provided with a slide pin 28 for forming the blind hole portion 7 of the leg body 1, and the slide pin 28 is indicated by an arrow H. It is slidable in the longitudinal direction and can be pulled out horizontally after injection molding.

Further, as shown in FIG. 9, the slide pin 28
Is a cylindrical portion 29 on the base side, a small-diameter column portion 30 integrally formed at the center of the tip end surface thereof, and one side is integrally formed on the outer peripheral surface of the small-diameter column portion 30 as a right angle in the circumferential direction and the other side is Column part 29
A plurality of triangular plate-shaped pieces 31 ... Formed integrally on the front end surface of the same along the radial direction.

The blind hole portion 7 of the leg body 1 is formed by the small diameter column portion 30 of the slide pin 28, and the groove portions 9 ... And the ribs 10 are formed by triangular plate-shaped piece portions 31. It

As shown in FIG. 10, the slide pin 28
It is also possible to form only triangular plate-shaped piece portions 31 ... And insert the metal nut member 3 between the piece portions 31. By doing so, the metal nut member 3 can be inserted by injection molding. It can be embedded in the leg body 1.

In the illustrated example, four triangular plate-shaped pieces 31 ... Of the slide pin 28 are formed, but two, three.
It is also preferable to form a single piece or a plurality of five or more pieces. By doing so, the groove portions 9 ... Of the leg body 1 (of FIGS. 4 and 5) described above are formed in a plurality of two, three or five or more than four, and the groove portions 9 ... The same number of ribs 10 ... Will be formed.

Thus, as shown in FIGS. 6, 7 and 8, the molten thermoplastic resin M is injected and injected from the resin injection passage 33 into the hollow portion 25, and in the flow of the thermoplastic resin M. Then, the gas is continuously injected from the gas injection passage 34 at a controlled pressure.

The gas to be injected is an inert gas, preferably nitrogen gas.

The thermoplastic resin M thus injected is
It spreads along the inner wall surface 36 of the hollow portion 25 and covers the entire inner wall surface 36, and an air chamber is formed inside by the gas.

Then, the thermoplastic resin M is solidified while maintaining the pressure of the injected gas. As a result, the volume decrease due to the volume contraction accompanying the solidification of the thermoplastic resin M is
It is compensated by the pressure of the retained gas.

That is, the layer of the thermoplastic resin M is solidified while being pressed against the wall surface inside the hollow portion 25 by the pressure of the gas inside thereof. Therefore, so-called "shrinkage" does not occur near the corners where the wall thickness is relatively large.

Thus, after the thermoplastic resin M is solidified, the pressure of the gas inside is made equal to the pressure of the outside air. Further, by pulling out the slide pin 28 in the horizontal direction and removing the upper mold 26 upward, the leg body 1 is formed.

When the thermoplastic resin M is solidified, a boss-shaped body (not shown) which is integral with the leg body 1 is formed at the tip of the resin injection passage 33. The boss-shaped body is an upper mold 26. When detaching, separate from the leg body 1.

Further, a cylindrical vertical protrusion 35 of the lower mold 27,
Since a frictional force is generated between the formed leg body 1 and the small tubular body 18, the upper mold 26 can be easily removed upward.

The formed leg body 1 is a lower mold 27.
It is held upright by the vertical protrusions 35. This allows
The formed product can be prevented from being scratched and taken out easily.

It should be noted that the resin injection passage 33 and the gas injection passage 34 may be freely provided at locations other than those in the above embodiment.

Further, in the above example, only one set of the resin injection passage 33 and the gas injection passage 34 is attached, but it is also possible to attach two sets thereof.

Next, FIG. 11 shows a process of forming a leg body of another embodiment.

In this example, the parting line P is in the middle of the vertical direction.

Specifically, the surface portion 40 (forming the horizontal wall portion 6 of the leg body 1) of the upper die 26 and the parting line P are flush with each other.

The portion below the parting line P--that is, the portion below the horizontal wall portion 6 of the leg body to be formed--is tapered so as to gradually contract downward. Further, the portion above the parting line P has a tapered shape that gradually shrinks upward.

Further, the resin injection passage 33 and the gas injection passage 34 are individually provided.

That is, in the illustrated example, the resin injection passage 33 is provided in the upper die 26, and the gas injection passage 34 is provided in the lower die 27. In this way, the resin injection passage 33 and the gas injection passage 34
It is also desirable to attach and separately.

Thereafter, the top plate receiving cushion 2 and the metal nut member 3 are attached to the leg body 1 as a product taken out from FIG. 11 as in the case described with reference to FIG. (Note that the nut member 3 may be inserted in advance at the time of molding in FIG. 11.)

The present invention can be freely modified in design within the scope of the invention other than the above-mentioned embodiments, and it is preferable that the leg body 1 is formed into a hollow substantially cylindrical shape, for example.

[0068]

The present invention has the following significant effects with the above-mentioned configuration.

According to the leg of the home mantrel according to claim 1, the metal nut can be easily and firmly attached to the leg body 1.

The groove 9 around the blind hole 7 ...
When the metal nut member 3 is press-fitted, the blind hole portion 7 is elastically deformed to easily expand the diameter, and the metal nut member 3 can be easily press-fitted.

Further, the rigidity and strength of the wall portion forming the blind hole portion 7 and the groove portion 9 of the leg body 1 can be increased.

Further, the leg body 1 can be integrally formed by injection molding, and the overall weight can be reduced.

Furthermore, so-called "shrinkage" does not occur at each corner of the leg body 1 and the leg body 1 can be formed in an accurate shape.

According to the leg of the home mantrel of the second aspect, the same effect as the leg of the platform of the first claim of the first aspect can be obtained, and it is the boundary between the upper mold 26 and the lower mold 27. The parting line P can be near the bottom wall portion 17 of the leg body 1.

The leg body 1 immediately after the injection molding is the lower mold.
It remains in the standing state on 27, and the leg body 1 can be prevented from being scratched and taken out from the mold easily.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a leg of a home tatami frame of the present invention.

FIG. 2 is a plan view.

FIG. 3 is a cross-sectional view illustrating a usage state.

FIG. 4 is a perspective view illustrating a main part.

FIG. 5 is a perspective view illustrating a main part.

FIG. 6 is a cross-sectional view illustrating a process of forming a leg body.

FIG. 7 is a cross-sectional view illustrating a process of forming a leg body.

FIG. 8 is a cross-sectional plan view illustrating a process of forming a leg body.

FIG. 9 is a perspective view showing a main part of a slide pin.

FIG. 10 is a perspective view showing a modified example of the slide pin.

FIG. 11 is a cross-sectional view illustrating a forming process of another embodiment of the leg body.

FIG. 12 is a cross-sectional view of an essential part showing a conventional example.

[Explanation of symbols]

 1 Leg body 3 Metal nut member 5 Vertical wall portion 7 Blind hole portion 8 Hollow chamber 9 Groove portion 10 Rib 16 Mounting bolt 17 Bottom wall portion 18 Small tubular body A Home Tatami frame

Claims (2)

[Claims] 1. A leg body 1 having a substantially uniform thickness as a whole is formed by injecting a gas into an uncured resin during injection molding so as to integrally have a hollow chamber 8 therein, and further, The vertical wall portion 5 near the upper end is provided with a blind hole portion 7 in the center and a plurality of groove portions 9 ... Consecutively radially provided from the central blind hole portion, and the hollow chamber 8 is formed by the wall portion forming the groove portions 9 ...
Ribs 10 are formed on the side of the vertical wall 5, and the blind hole 7 of the vertical wall 5 is press-fitted with the metal nut member 3 to which the mounting bolt 16 for the home rattling frame A is screwed. The legs of the home tatami frame, which are embedded by insert molding during injection molding. 2. The leg body 1 has a tapered shape that expands downward, and a small tubular body 18 is integrally erected so as to project from the bottom wall portion 17 into the hollow chamber 8. The leg of the home tatami frame according to claim 1.