JP2020116605A - Sand-mold caster for cast tube and method of positioning core therefor to metal frame - Google Patents

Abstract

To provide a sand-mold caster for a differing-shaped tube allowing for positioning and setting a core 4 to and in molds 2a, 2b with easiness and simplicity.SOLUTION: A sand-mold caster A for a differing-shaped tube consists of upper and lower molds 2a, 2b in which sand a is molded in metal frames 1a, 1b, a core 4 inserted in a cavity 3 of the upper and lower molds laid together, and means for fixing both ends of the core respectively to the metal frames. The core 4 is provided by molding sand a around a core-metal 5 and fixing a horizontal rod 7 to one end of the core-metal 5 at a central portion thereof. The fixing means at one end of the core 4 supports/fixes one end of the horizontal rod 7 at between upper and lower long-nosed portions 8, 8 on a side face of the metal frame 1a, 1b by screw jacks 9 and supports/fixes the other end of the horizontal rod 7 to the other long-nosed portions 8, 8 on the side face of the metal frame 1a, 1b, with the other end of the core-metal 5 fixed to a side face of the metal frame 1a by a fixed clamp 12. In this supporting/fixing state, the inclination angle (attaching angle) relative to the other end of the horizontal rod 7 can be adjusted by the upper and lower screw jacks 9 at the one end of the horizontal rod, and hence it is comparatively easy to rotate/fix the core in a cylindrical shape or the like about its axis without restriction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sand casting apparatus for casting pipes such as straight pipes and deformed pipes used for water and sewer pipes and the like, and a method for positioning the core of the casting pipe in a metal frame.

Unlike a straight pipe, a deformed pipe of this type has a bent pipe axis, and therefore a sand casting method is mostly used instead of the centrifugal casting method.
This sand mold casting method will be described with reference to FIGS. 1 to 6 showing an embodiment of the present invention. Upper and lower molds 2a and 2b in which sand a is molded in metal frames 1a and 1b, and upper and lower molds. And a core 4 loaded in a cavity 3 in which the molds 2a and 2b are stacked. The core 4 is formed by molding sand a around a core metal 5.
The deformed pipe P is cast by injecting (pouring) the molten metal into the cavities 3 of the upper and lower molds 2a and 2b in which the core 4 is loaded and stacked (see Patent Documents 1 and 2).

JP-A-56-154251 JP-A-3-13263

At the time of pouring the molten metal, buoyancy may be generated in the core 4 due to the molten metal, which may cause floating of the core or rotation of the core.
When the core floats or the like, the thickness of the cavity 3 around the core 4 (the distance between the outer surface of the core 4 and the inner surfaces of the molds 2a and 2b) changes (dimensional change occurs), and the dimensional accuracy deteriorates. Sometimes. Conventionally, the core 4 is lifted up by firmly fixing the baseboard parts at both ends of the core, but since the baseboard part is cylindrical, the force in the direction in which the core rotates due to the buoyancy of the molten metal is applied. Since it is difficult to hold down, positioning of the core in the rotational direction, which is performed while adjusting the cavity when loading the core, is a complicated task. In particular, in the case of a deformed pipe, the thickness of the cavity 3 around the core 4 is likely to change because the pipe axis is bent.
For this reason, conventionally, the wall thickness defect is dealt with by setting the wall thickness in consideration of the deformation allowance of the product (cast product) or by setting the overall wall thickness excessively. Increasing this wall thickness results in the use of an excessive amount of molten metal, resulting in a large excess loss, which cannot meet today's demands for cost reduction.

Under the above-mentioned circumstances, the present invention has an object to make it possible to easily and easily align and set the core 4 in the molds 2a and 2b.

In order to achieve the above object, the present invention is a sand casting apparatus for a casting pipe, wherein upper and lower molds in which sand is molded in a metal frame and upper and lower molds are stacked in a cavity. It consists of a child and a means for fixing both ends of the core to a metal frame.The core molds sand around the core metal, and a horizontal rod is attached to one end of the core metal at its center. The fixing means at one end of the core is such that one end of the horizontal rod is supported and fixed between the upper and lower tengu parts of the side face of the metal frame by a screw jack, and the other end of the horizontal rod is attached to the side face of the metal frame. The other end of the core is supported and fixed, and the other end of the core has a structure in which the other end of the cored bar is fixed to the side surface of the metal frame by a fixed clamp.

The sand casting apparatus for a casting pipe of this configuration is such that first, at one end of the core bar, one end of a horizontal rod fixed to the core bar is supported and fixed by a screw jack between the upper and lower tengu parts of the side surface of the metal frame. , The other end of the horizontal rod is supported and fixed to another tengu part on the side surface of the metal frame. At this time, the angle of inclination (mounting angle) with respect to the other end of the horizontal rod can be adjusted by the screw jack at one end of the horizontal rod, so that it is relatively free to rotate and fix the cylindrical core or the like around its axis. It's easy.
Next, the other end of the cored bar, which is the other end of the core, is fixed to the side surface of the metal frame by a clamp. This fixing prevents the core from moving axially during pouring.

In this configuration, when the casting pipe has an opening at one end and an insertion end at which the other end is inserted into the receiving end, the fixing means at one end on the receiving end side of the core is such that both ends of the horizontal rod are Screw jacks are inserted between the upper and lower tengu parts of the frame side to support and fix, and the other end on the insertion opening side of the core has the other end on the insertion opening side of the core metal on the side of the metal frame. It can be fixed by a fixed clamp. This is because by fixing the receiving side first, the core is positioned by the receiving port having a diameter larger than that of the insertion port, so that the positioning is stable. Especially, it is effective in the case of a deformed tube.

Also, the other end of the core metal, which is the other end of the core, is fixed to the other end of the core bar at the center thereof without depending on the clamp, and one end of the horizontal bar is attached to the side surface of the metal frame. It is possible to have a structure in which the upper and lower tengu parts are supported and fixed by a screw jack, and the other end of the horizontal rod is supported and fixed to another tengu part on the side surface of the metal frame. At this time, as described above, both ends of the horizontal rod can be supported and fixed by interposing screw jacks between the upper and lower tengu parts on the side surface of the metal frame.

In the upper and lower molds in which sand is molded in the metal frame, a self-curing type in which a resin and a curing agent are mixed and cured with time, a gas curing type in which water glass is mixed and cured with CO ₂ gas, etc. However, these curing types are characterized by good dimensional accuracy and productivity because they can be removed from the mold after curing, and they are used appropriately.
The present invention can be applied to the casting of various casting pipes such as straight pipes and deformed pipes. It is also possible to employ those casting pipes in which one end is not a receiving port and the other end is not a receiving port that is inserted into the receiving port. Further, as the screw jack, those having conventionally well-known structures can be adopted, and for example, a turnbuckle is used. It is preferable that the turnbuckle has a seat that is directed to the lateral rod to stabilize and fix the lateral rod.

Since the present invention is configured as described above, it is possible to effectively prevent the core from floating and rotating, reduce the phenomenon of poor wall thickness, and reduce excessive loss due to dimensional deformation prevention during pouring (of setting the wall thickness). It becomes possible to manufacture the deformed pipe at low cost and with high precision.

Front perspective view of an embodiment of a sand casting apparatus for a casting pipe according to the present invention Rear perspective view of the same embodiment Front view of the same embodiment A schematic plan view of a lower mold in which the upper mold is removed and a core is loaded in the same embodiment. The perspective view which reversed the upper mold of the same embodiment. The perspective view of the lower mold of the same embodiment The perspective view which installed the core of the same embodiment on the ground. The perspective view which set the core of the same embodiment in the lower mold.

1 to 8 show an embodiment of the sand casting machine according to the present invention, and the sand casting machine A of this embodiment has upper and lower molds in which the sand a is cast in the metal frames 1a and 1b as in the conventional case. 2a and 2b, and a core 4 loaded in a cavity 3 in which upper and lower molds 2a and 2b are stacked.

In the molds 2a and 2b, the sand and the curable resin are kneaded by a mixer as in the conventional case, and the metal molds 1a and 1b are put on the respective main molds (not shown). Then, the kneading sand a is put in from above (lattice-like surface in FIG. 1), and molding is performed while compacting.
After this, when the sand a in the metal frames 1a and 1b is solidified, the main mold is demolded, both molds 2a and 2b are inverted and placed on the ground such as a concrete floor. The upper mold 2b and the lower mold 2a shown in are obtained.

On the other hand, in a separate process, the core metal 5 is set in a core wooden mold (not shown), the wooden mold is erected and the kneading sand a is put into the wooden mold, and core molding is performed while compacting. .. After this, when the sand a around the core metal 5 hardens, the core wooden mold is released.
At this time, a horizontal rod 7 is passed through a cylindrical body 6 fixed to one end of the core metal 5, and a wedge 7a is driven into the cylindrical body to fix the middle of the horizontal rod 7 to one end of the core metal 5. .. Further, an appropriate clamp (see FIG. 2) is also provided on the other end of the cored bar 5. Using the horizontal rod 7 and the clamp, the core 4 is placed on the placing table 7b as shown in FIG.

In this way, the upper and lower molds 2a, 2b and the core 4 are molded, and the core 4 is set in the lower mold 2a as shown in FIG. At this time, both ends of the horizontal rod 7 fixed to the cored bar 5 are supported and fixed by interposing turnbuckles 9 and 9 serving as screw jacks between the both ends of the tengu 8 on the side surface of the metal frame 1a. The turnbuckle 9 has a receiving seat 9a consisting of an arcuate shape or a U-shaped piece at the top and bottom, and by turning the main body (body part) 9b, the receiving seat 9a is advanced and retracted via a screw and the horizontal rod 7 and The tengu portion 8 is pressed or separated.
The other end of the cored bar 5 is supported and fixed by a clamp 12 attached to a support base 11 fixed to the metal frame 1a, as shown in FIG. The clamp 12 is a known one in which a cap screw rod 12b is threaded through a U-shaped main body 12a fixed to the support 11. By the support and fixation by the clamp 12, the core 4 is prevented from moving in the axial direction during pouring.

When the cored bar 5 is supported and fixed to the metal frame 1a, the turnbuckle 9 is used to adjust the space between the horizontal rod 7 and the tengu part 8 and the axis of the cavity 3 formed by the upper and lower molds 2a and 2b and the core 4. The cores of (core 5) should be aligned. That is, the gap between the outer surface of the core 4 and the inner surface of the mold 2a (the inner surface of the cavity 3) is measured by a gap gauge, and the turnbuckle 9 adjusts the gap between the horizontal rod 7 and the tengu portion 8 so that their axes coincide.
The positioning of the core 4 by the turnbuckle 9 is not simply fixed, but also the positioning of the core 4 in the vertical direction and the rotation direction around the axis can be easily performed, resulting in good workability.

After that, the lower mold 2a is covered with the upper mold 2b, and the sprue and the riser are set (these are well known and are not shown). At this time, the lower mold 2a and the upper mold 2b are positioned by the fitting of the pin 10 formed at the interface (split surface) and the fitting hole 10' into which the pin fits. The position and number of the pin 10 and the fitting hole 10' are arbitrary.

In addition to the sprue and the riser, the upper and lower molds 2a and 2b are appropriately provided (formed) with a stop, a spout, a spout bottom, a runner, a weir, degassing, and frying. Although these are well known, although not shown, for example, the sprue is formed on the insertion side, the sprue bar is formed from the sprue to the side of the sand mold in the radial direction, and then the runner is inserted. It is extended to the tip surface of the mouth, and further formed in a downward arc shape up to the middle of the radial direction. The hot water is provided at the upper part of the brim of the insertion port and the receiving port.

In a state where the upper and lower molds 2a and 2b are overlapped (set), the upper and lower molds 2a and 2b are mechanically fastened at appropriate positions with a vise, and the horizontal rod 7 is attached to the tengu portion 8 of the upper metal frame 2b. A turnbuckle 9 is interposed between and to be fixed (see FIGS. 1 and 2). As a result, both ends of the horizontal rod 7 are supported and fixed by interposing the turnbuckles 9 between the upper and lower tengu parts 8 on the side surfaces of the metal frames 1a and 1b, respectively, and the core 4 is fixed to the upper and lower molds 2a, It is stably set in 2b. The split surfaces (parting lines) of the upper and lower molds 2a and 2b are formed of molding sand and are in close contact with each other.
A crane is used to move the molds 2a, 2b and the core 4, and at that time, a rope or a chain is locked to the tengu 8 to lift them.

In a state where the upper and lower molds 2a and 2b are integrated, molten metal is injected (molten) into the cavity 3 from the spout to cast the deformed pipe P (see FIG. 4). At the time of this pouring, especially in the case of the deformed pipe P, since the pipe axis is bent, a rotational force is generated in the direction in which the back side of the bent portion having a large surface area floats, but the metal frames 1a, 1b of the horizontal rod 7 are generated. It is effectively fixed against the rotational force to prevent its rotation.
Further, since the core 4 is firmly fixed to the molds 2a and 2b by the horizontal rod 7 and the like, the dimensional deformation of the cavity 3 is small, it is not necessary to set an excessive thickness, and the molten metal has an excessive weight ratio. Reduce.

In the state where the upper and lower molds 2a and 2b are overlapped (set), the axis of the cavity 3 and the axis of the core 4 (core 5) can be made to coincide with each other. The turnbuckle 9 on the lower side of the end of 7 aligns the axis of the cavity 3 with the axis of the core 4 (core 5), and then the turnbuckle 9 on the upper side fixes the core 4 in position. If the upper turnbuckle 9 is adjusted first, the lower turnbuckle 9 may cause the core 4 to move when the axis of the cavity 3 and the axis of the core 4 (core 5) are aligned. If the core 4 moves, it is necessary to perform the confirmation work using the gap gauge again, which is complicated.

Further, in this embodiment, the other end of the horizontal rod 7 (right end in FIG. 1) is also supported and fixed to the tengu parts 8 of the upper and lower molds 2a and 2b through the turnbuckle 9, but One may be supported and fixed by interposing a bar member or the like between the upper and lower molds 2a and 2b and the tengu parts 8 and 8.
Furthermore, if the turnbuckle 9 is provided at least at one position between the ends of the horizontal rod 7 and the left and right upper and lower tengu parts 8 at least one place, the turnbuckle 9 expands and contracts to move the core metal 5 in the vertical direction. And the adjustment of the rotation direction is possible. When the number of this turnbuckle 9 is one, a bar is interposed between the lower end of the horizontal rod 7 where the turnbuckle 9 is not provided and the tengu part 8 of the lower mold 2a, and the turn below the end of the horizontal rod 7 is made. After adjusting the up-down direction and the rotating direction of the cored bar 5 (core 4) with the buckle 9, a rod or the like is appropriately interposed between both ends of the horizontal rod 7 and both dough-neck portions 8 of the upper mold 2b.
In this way, if both ends of the core 4 (core metal 5) are fixed and one end of the horizontal rod 7 is supported by the turnbuckle (screw jack) 9, the turnbuckle 9 has an inclination angle with respect to the other end of the horizontal rod 7. (Mounting angle) can be adjusted.

Similarly to the one end side, the other end portion of the core metal 5 in FIG. 2 can employ a fixing means such as a turnbuckle 9 and a horizontal rod 7.
The core 4 may be supported and fixed to the lower mold 2a by first supporting and fixing the other end (front side in FIG. 2) of the cored bar 5 and then supporting and fixing one end.

Although the embodiment is the sand casting of the NS bent curved pipe P, the present invention can be applied to a straight pipe as well, and the type of the cast pipe P is not limited to the NS bent bent pipe, and other types. It goes without saying that various types of can be adopted.
As described above, it should be considered that the embodiments disclosed this time are illustrative in all points and not restrictive. The scope of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

1a Lower metal frame 1b Upper metal frame 2a Lower mold 2b Upper mold 3 Cavity 4 Core 5 Core metal 7 Side rod
8 Tengu part 9 Screw jack (turnbuckle)
9a Screw jack (turnbuckle) receiving seat 9b Main body 11 Supporting base 12 Clamp P Deformed tube a Sand (kneading sand)

Claims (8)

A sand casting machine (A) for a casting pipe,
A core to be loaded in a cavity (3) in which upper and lower molds (2a, 2b) in which sand (a) is placed in a metal frame (1a, 1b) and upper and lower molds (2a, 2b) are stacked. (4) and means for fixing both ends of the core (4) to the metal frames (1a, 1b), respectively,
The core (4) is one in which sand (a) is molded around a cored bar (5), and a horizontal rod (7) is fixed to one end of the cored bar (5) at its central part. ,
The fixing means at one end of the core (4) supports and fixes one end of the horizontal rod (7) between the upper and lower tengu parts (8) on the side surfaces of the metal frames (1a, 1b) with a screw jack. At the same time, the other end of the horizontal rod (7) is supported and fixed to another tengu part (8) on the side surface of the metal frame (1a, 1b),
The other end of the core (4) is a sand casting apparatus for a casting pipe in which the other end of the core metal (5) is fixed to the side surfaces of the metal frames (1a, 1b) by a fixed clamp (12). One end of the casting pipe is a receiving port, the other end is an insertion port to be inserted into the receiving port,
The fixing means at one end of the core (4) on the receiving side is a screw jack between the both ends of the horizontal rod (7) and the upper and lower tengu parts (8) on the side surfaces of the metal frames (1a, 1b). Interspersed with each other to support and fix,
The other end on the insertion opening side of the core (4) has the other end of the core metal (5) fixed to a side surface of the metal frame (1a, 1b) by a clamp (12) fixed. Sand casting equipment for casting pipes. The other end of the core (4) is fixed to the other end of the cored bar (5) at the center thereof without depending on the clamp (12). ) Is supported and fixed to the upper and lower tengu parts (8) on the side surfaces of the metal frame (1a, 1b) by a screw jack, and the other end of the horizontal rod (7) is connected to the metal frame (1a, 1b) The sand casting apparatus for a casting pipe according to claim 1 or 2, which is supported and fixed to another tengu (8) on the side surface. The sand casting apparatus for a casting pipe according to any one of claims 1 to 3, wherein the casting pipe is a deformed pipe (P). The sand casting apparatus for a casting pipe according to any one of claims 1 to 4, wherein the screw jack is a turnbuckle (9). Sandcasting device for casting pipes according to claim 5, characterized in that the turnbuckle (9) has a seat (9a) which is directed against the lateral rod (7). In the sand mold casting method of casting pipe,
The core (4) is loaded in the cavity (3) in which the upper and lower molds (2a, 2b) in which the sand (a) is placed in the metal frames (1a, 1b) are stacked, and the core (4) is loaded. A method for positioning the metal frame (1a, 1b), comprising:
A horizontal rod (7) is fixed to one end of a core metal (5) of the core (4) at its central portion, and one end of the horizontal rod (7) is placed above and below the side faces of the metal frames (1a, 1b). While being supported and fixed by a screw jack to the tengu part (8), the other end of the horizontal rod (7) is also supported and fixed to another tengu part (8) on the side surface of the metal frame (1a, 1b). The other end of the core (4) is a method of positioning the core on the metal frame by fixing the other end of the cored bar (5) to a side surface of the metal frame (1a, 1b) by a clamp (12). One end of the casting pipe is a receiving port, the other end is an insertion port to be inserted into the receiving port,
One end of the core (4) on the receiving side is provided with a screw jack between both ends of the horizontal rod (7) and the upper and lower tengu parts (8) on the side surfaces of the metal frames (1a, 1b). Then, the other end on the insertion opening side of the core (4) is clamped by a clamp (12) fixed to the side surface of the metal frame (1a, 1b). The method for positioning the core on the metal frame according to claim 7, wherein the core is fixed.

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