JPS6140533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for covering curved pipes such as pipe joints by injection molding.

[Prior Art] In recent years, pipe joints used in gas and water pipes have come to be coated with resin to prevent holes from forming due to electrolytic corrosion and the like.

Conventional coating molding equipment for applying resin coating is
As shown in FIG. 1, insert the masking jig 7 into the opening of the curved pipe 8, and
3 on the masking holding part 9 of the lower mold 6 to hold the bent pipe 8 on the lower mold 6, then close the upper and lower molds,
The molten resin is press-injected from the injection port 16 to cover and mold the surface of the curved pipe.

In this case, when the curved tube 8 to be coated has a large diameter, the weight of the curved tube 8 is large, so the grip portion 13 of the masking jig 7 is made as long as possible in order to support the curved tube 8 in a fixed position within the mold. At the same time, the bent pipe 8 is made large in diameter, and the weight of the grip part 13 supports the curved pipe 8 to prevent it from falling into the recess in the mold, and after maintaining a gap equal to the thickness of the coating resin, the upper mold 10 is lowered to press fit the resin. A method was taken to do so.

[Problem that the invention attempts to solve] The above conventional technology has the following drawbacks.

(1) The total weight of the curved pipe with the masking jig inserted increases, making loading it into the mold a laborious task.

(2) As the mold becomes larger, the cost of the mold becomes more expensive, and the number of cavities becomes smaller, resulting in poor efficiency.

The present invention aims to eliminate the above-mentioned drawbacks.

[Means for Solving the Problems] The gist of the present invention is to provide a masking jig which is disposed within a cavity formed by an upper mold and a lower mold, keeping a predetermined gap from the cavity surface, and has a masking jig in the opening. In a coating device that coats the surface of the bent pipe with resin for the above-mentioned gap by injection molding, the upper mold is suspended in a recess of the upper mold holding stand so that it can be raised and lowered, and a support rod for supporting the bent pipe is provided. It protrudes from the cavity surface of the lower mold and is connected to an elevating plate which is disposed on the lower surface of the lower mold and is biased upward, and the elevating plate holds the upper mold when the upper mold holding table and the lower mold match. It is pushed down by a fixing pin that aligns the upper mold holder fixed to the table and the lower mold, or by a push-down rod that is connected to an elevating plate and in contact with the lower surface of the upper mold holder, and protrudes from the lower mold cavity surface. This apparatus is characterized in that the tip of the support rod descends to the cavity surface.

[Function] In other words, when performing resin coating molding on a curved pipe, the apparatus of the present invention first penetrates the lower mold and projects into the cavity of the lower mold from below. The lower part of the bent pipe loaded in the mold is supported to prevent the bent pipe from falling to the inner surface of the lower mold, and then the upper mold holder is lowered and the upper mold suspended from the upper mold holder is connected to the lower mold. By contacting the upper and lower molds, the masking jig is firmly held by the upper and lower molds, and the lower end of the support rod provided below the lower mold is fixed, as well as being biased upward by a spring. By pushing down the plate, the front support rod is lowered to the cavity surface of the lower mold, and the gap between the inner surface of the upper and lower molds and the curved pipe is maintained with a gap equal to the thickness of the resin film to be injection molded. .

[Example] An embodiment of the present invention will be described below.

In FIG. 2, the curved pipe 8 with the masking jig 7 inserted into its opening is housed in the fixed position of the lower mold 6 by fitting the masking jig 7 into the masking holding portion 9 of the lower mold 6.

In that case, the cavity surface of the lower mold 6 in the part where the curved tube 8 is housed is deepened by the thickness of the resin film that is injected and formed on the outer periphery of the curved tube 8.
The bent pipe 8 falls into the cavity of the lower mold as it is. In order to prevent this, the lower end of the support rod 5 is fixed to the lifting plate 4 provided below the lower mold 6, and
The upper part of the support rod 5 penetrates the lower mold 6 and supports the lower part of the bent pipe 8 to prevent it from falling into the lower mold cavity, and the distance between the bent pipe 8 and the inside of the lower mold cavity is adjusted to the thickness of the resin film. It is designed to be held so as to keep it for a certain amount of time.

Further, below the lifting plate 4, there is a lower table 1 with a built-in push-up pin 3, and the lifting plate 4 is supported via the push-up pin 3 whose head is pushed up by a spring 2 housed in the lower table 1. ing. Further, the lower surface of the upper mold 15, which is vertically suspended from the holding table 10 by means of hanging bolts 14, protrudes below the lower surface of the upper mold holding table 10. Furthermore, the lower end of a push-down rod 11 is fixed to the lifting plate 4 and extends upward, passing through the lower mold 6 and coming into contact with the lower mold surface of the upper mold holder 10.

When the upper mold holder 10 is lowered and the lower surface of the upper mold 15 comes into contact with the upper surface of the lower mold 6, the upper and lower molds completely hold the masking jig 7 inserted into the curved pipe 8.

When the upper mold holder 10 further descends, the upper mold holder 10 pushes down the elevating plate 4 via the push-down rod 11 to lower it. Then, the upper end of the support rod 5 whose lower end is fixed to the lifting plate 4 is separated from the lower surface of the curved pipe 8 and is lowered to the surface of the cavity of the lower mold 6, and the lower surface of the upper mold holding base 10 and the upper surface of the lower mold 6 The curved pipe 8 held through the masking jig 7 by this contact is fixed with a space equal to the thickness of the resin coated between the upper and lower molds.

Next, in FIG. 3 showing another embodiment of the present invention, only the lowering mechanism of the elevating plate 4 to which the support rod 5 is fixed differs from the embodiment of FIG. 2, but the rest is the same as the previous embodiment.

Fixing pins 12 that align the plurality of upper mold holders fixed to the upper mold holder 10 and the lower mold 6 extend downward and pass through the lower mold 6, thereby completely aligning the upper and lower molds. At the same time, its lower end is in contact with the upper surface of the elevating plate 4, and as the upper mold holder 10 descends, the elevating plate 4 is pushed down and the support rod 5 is lowered to the surface of the cavity of the lower mold 6.

[Effects of the Invention] As described above, with the curved pipe 8 supported within the lower mold by the support rod 5, the upper mold 15 first descends and presses the upper surface of the masking jig 7 of the curved pipe 8, With the masking jig 7 being held down by the upper and lower molds 15 and 6, the support rod 5 supporting the lower surface of the curved tube 8 is lowered, and the upper mold holding part 10 and the lower mold 6 are brought into complete contact with each other. Since the curved tube 8 is fixed within the upper and lower molds, there is no displacement of the curved tube 8 due to mold matching, and accurate resin coating molding can be performed.

In addition, the weight of the masking jig inserted into the curved pipe can be reduced, making it easier to load the curved pipe into the mold.In addition, since a large masking jig area is not required in a mold with the same area, the number of molds can be reduced. This also makes it possible to reduce mold costs and improve productivity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional bent pipe resin coating molding apparatus in an open state, and FIGS. 2 and 3 are principal part sectional views showing an embodiment of the bent pipe resin coating molding apparatus according to the present invention. be. 4: Elevating plate, 5: Support rod, 6: Lower mold, 7: Masking jig, 8: Bent pipe, 10: Upper mold holding stand, 1
1: Press down bar, 12: Fixing pin, 15: Upper mold.

Claims (1)

[Claims] 1 Inside the cavity formed by the upper mold and the lower mold, resin is injected into the surface of a curved pipe that is placed with a predetermined gap between the cavity surface and the masking jig attached to the opening. In a coating device that performs coating by molding, the upper mold is suspended in a recess of an upper mold holder so that it can be raised and lowered, and a support rod that supports the bent pipe protrudes from the cavity surface of the lower mold and is disposed on the lower surface of the lower mold. and is connected to an elevating plate which is biased upward, and when the upper mold holder and the lower mold match, the elevating plate changes the position of the upper mold holder fixed to the upper mold holder and the lower mold. The tip of the support rod protruding from the lower mold cavity surface is lowered to the cavity surface by being pushed down by a pressing rod that is connected to the mating fixing pin or the lifting plate and in contact with the lower surface of the upper mold holder. A resin coating molding device for bent pipes, which is characterized by: