JPH035894B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a blowing nozzle for mold making, and particularly to a blowing nozzle for mold making having a mechanism in which a tongue-like piece at the tip is forcibly pushed open by a pipe installed in a flexible nozzle. Regarding.

Conventional technology For example, the cold box molding method, which uses wet molding sand, uses an open flexible nozzle (generally called a peep nozzle) without tongues (for example, 38056), but in the shell molding method, for example, which uses dry molding sand,
Although various proposals have been made as means for preventing molding sand from remaining in the blowing section, there is currently no perfect technical means.

As a flexible nozzle in the form of a peep nozzle when dry molding sand is used, Utility Model Publication No. 51-8008, Utility Model Publication No. 57-29956, and Utility Model Publication No. 57-29957 have been developed and put into practical use by the present applicant. However, in these known techniques, the tongues at the tip of the nozzle are pushed open by the injected molding sand, so the blowing resistance of the molding sand is large, the filling of the mold is poor, and the tongues are It has drawbacks such as rapid wear. The present applicant has developed Japanese Patent Publication No. 57-3452 as an improvement on these known techniques, but this nozzle also has drawbacks such as the valve seat being prone to wear, the mechanism being complicated, and the product cost being high.

Problems to be Solved by the Invention When dry molding sand is used as in the shell molding method, a blowing nozzle with a flexible packing is usually pressed against the flat surface of the upper surface of the mold to perform the blowing. Since the blowing nozzle cannot be brought close to the mold surface, the unnecessary part of the mold, generally called the horn or candle, is formed.
After molding, this part must be cut and removed from the boundary with the mold.

Furthermore, a small amount of excess sand remains on the top surface of the injection port of the mold, and it is not possible to proceed to the mold release process as it is, so a cleaning process to remove the excess sand with a scraper etc. is required immediately after injection (before the molding sand hardens). It is.

As mentioned above, the conventional method has the following flaws; (1) Removal of excess molding sand and cleaning process are necessary; (2) Excess sand and molding sand in the horn portion are wasted; (3) ) When the horn is removed from the mold, the horn breaks, causing damage to the mold body, or falling into the mold cavity, requiring removal work. (4) Smoothness of the mold surface in the area where the horn is removed. It has poor properties and causes defects on the surface of castings.

Means for solving problems In order to solve the problems of the conventional method as mentioned above,
The present inventor has succeeded in developing the present invention as a result of various studies and experiments, and the technical configuration of the present invention is as specified in each of the claims above.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of the present invention will be explained in detail based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the nozzle of the present invention, and FIG. 2 is a plan view of the end face of the flexible nozzle.

1 is a mounting housing for the blow plate;
On its outer periphery there is a screw part A for mounting to the blow plate.
The inner peripheral surface is provided with a threaded portion that fits into the threaded portion of the internal pipe 2, and further provided with a recess for locking a spring 4, which will be described later.

The interior pipe 2 is provided with a flange B at approximately the center of its outer periphery, and a small diameter "R" is provided at the corner of the outer periphery of the tip of the interior pipe.

Reference numeral 3 denotes a collar, one end 3' of which engages with the collar B of the interior pipe 2, and the other end 3'' of which serves as an engagement part of the flexible nozzle 5.

The flexible nozzle 5 is slidably fitted and attached to the interior pipe 2, and its base is connected to the collar 3.
It is locked at the end 3'' of.

A spring 4 is loaded between the recess of the housing 1 and the collar 3, and is compressed when the nozzle of the present invention is pressed against a mold.

Further, the inner circumferential corner of the tip of the flexible nozzle 5 has an "R" in correspondence with the "R" of the outer circumferential corner of the tip of the interior pipe 2 described above, so that the opening and closing of the tongue-shaped piece is smooth. play an action.

Furthermore, a notch is provided in the vicinity of the end face of the tip of the flexible nozzle 5 as shown in FIG. D, and its function and effect will be described later.

FIG. 7 is a longitudinal cross-sectional view showing another example of the present invention. In this example, by attaching a sand prevention plate 1' to the housing 1, mold sand inside the inner pipe 2 can be removed even when the nozzle 5 is removed for replacement. This structure prevents the molding sand from being discharged from the blowhead.

FIG. 8 is a longitudinal cross-sectional view showing still another embodiment of the present invention, in which the internal pipe 2 is directly attached to the blow plate 6 without using the housing 1 as shown in the previous example. This is an example of a more simplified structure.

The blowing nozzle of the present invention has the above-mentioned configuration,
Its operating mode is briefly explained below: The tongue-shaped piece C at the lower end of the blow nozzle of the present invention attached to the blow plate 6 is closed, and the molding sand 7 in the blow head (not shown) thereby leaks to the outside. It never comes out (the state shown in Figure 3).

When the blow head (not shown) is crimped against the mold 8 by an external power (not shown), it is pushed back into the flexible nozzle 5 by the mold 8 and slides along the pipe 2. (Spring 4 is compressed).
When the flexible nozzle 5 is pressed, the relatively inner pipe 2 protrudes in the direction of the tongue at the lower end of the flexible nozzle, working to forcefully open the tongue C (Fig. 4). (Illustrated).

Almost simultaneously when the tongues C are pushed open, the molding sand 7 in the blowhead is blown into the cavity formed by the molds 8 and 9 by compressed air supplied to the blowhead to form the mold 10.

The flexible nozzle 5 pressed against the mold 8 has H, J
The air for sand blowing will not leak outside.

The outer periphery of the lower end of the flexible nozzle expands as the tongue-like piece C is pushed open and contacts the inner periphery (part F) of the sand blowing hole K of the mold 8, causing the blown sand to flow further. Prevents blow-up and reduces mold burrs.

The lower inner periphery of the flexible nozzle 5 and the lower outer periphery of the pipe 2 also come into contact (section G) due to the reaction force of the flexible nozzle outer periphery contact portion F, and the flexible nozzle and the pipe 2 slide. Prevents sand grains from entering the surface.

The pressure on the blowhead is released, and in the process of the blowhead rising, the flexible nozzle returns to its original position under the action of the spring 4, and the tongue of the nozzle closes.

After the blowing nozzle exits from the blowing hole K of the mold 8, a small amount of surplus sand L remains in the sand blowing part of the mold 10, as shown in FIG. This surplus sand L is pressed and shaped into a predetermined shape M by a mold extrusion/shaping pin 11 (as shown in FIG. 6). Note that, depending on the amount of excess sand L, the shaping part M of the mold 10 will be convex or concave, but if the amount of penetration of the blow nozzle into the mold 8 is adjusted and set in advance, a correct shaping surface can be obtained. I can do it.

Effects of the invention (1) When the flexible nozzle slides under external force, the tongue-like piece at its lower end is forcibly pushed open by the pipe, and at the same time, the outer periphery of the lower end expands and blows into the mold. Since the lower part of the mouth and the inner side of the base of the tongue are sealed (sealing effect of F and G in FIG. 4), it is possible to prevent molding sand from entering unnecessary parts.

(2) Since notches D are provided on each side of the flexible nozzle tip, the tongue-like piece has good bendability and can be opened easily.

(3) This is a mechanism in which the tongue-like piece is forcibly pushed open by an internal pipe, which eliminates molding sand blowing resistance and improves mold filling performance.

(4) The "R" on the outer periphery of the tip of the inner pipe allows the flexible nozzle to open and close smoothly and prevents damage to the flexible nozzle.

(5) The "R" inside the tip of the flexible nozzle increases the lifespan against repeated bending (if the "R" is not attached, cracks are likely to occur from that part).

(6) The structure is simple and the product cost is relatively low.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of the nozzle of the present invention;
Fig. 2 is a plan view of the end face of the flexible nozzle, Figs. 3 to 6 are schematic cross-sectional views showing the molding operation using the blowing nozzle shown in Fig. 1 over time, and Figs. 7 and 8 are the main FIG. 7 is a vertical cross-sectional view showing another example of the invention nozzle. In the figure: 1: Blow plate mounting housing, 2: Interior pipe, 3: Collar, 4: Spring, 5: Flexible nozzle, 6: Blow plate, 7: Molding sand, 8, 9: Upper and lower metals Mold, 10: Mold, 11: Mold extrusion and shaping pin, A: Housing screw part, B:
Collar, C: Tongue, D: Notch.

Claims (1)

[Claims] 1. An interior pipe that is equipped with a mechanism that can be fitted and fixed directly to a blow plate or to a blow plate mounting housing and that has a collar on its outer periphery, one end of which is locked to the collar. and a collar having the other end serving as a nozzle locking portion, a flexible nozzle slidably fitted to the interior pipe and locked to the nozzle locking portion of the collar, the blow plate or the housing, and the blow plate or housing. A blowing nozzle for mold making characterized by comprising a spring loaded between collars. 2. The blowing nozzle for mold making according to claim 1, wherein the tip of the flexible nozzle is provided with radial cuts to form a plurality of tongue-like pieces that can be opened and closed. 3. Claim 1 or 2, wherein a notch is provided around the end surface of the tip of the flexible nozzle.
Blow nozzle for mold making as described in Section 1.