KR20150069204A

KR20150069204A - The manufacture method of a integrated manhole's cover by evaporative pattern casting

Info

Publication number: KR20150069204A
Application number: KR1020130155341A
Authority: KR
Inventors: 남두호
Original assignee: 한국주철산업주식회사
Priority date: 2013-12-13
Filing date: 2013-12-13
Publication date: 2015-06-23

Abstract

A method for manufacturing a manhole cover using a destructive model method is disclosed. A method of manufacturing a mold made of a styrofoam having the same dimensions as the manhole cover using a model mold, a step of inserting the bolt into the mold and removing the bolt, thereby forming a coupling hole having a screw thread into which the bolt can be inserted A step of immersing the disappearing molding material in a mold material to apply and drying the mold material to the destructible molding material, and a step of removing the mold material and the disappearance pathway, Placing the molding sand to be fixed to the molding sand inside the molding sand to firmly squeeze the molding sand to remove the air in the molding sand so that the disappearance molding is buried and the upper end of the elimination passageway is exposed; The waste material is injected into the upper end of the exposed waste passage, A step of forming a casting material by curing the casting material, a step of separating the casting material from the casting material, and a step of finishing the separated casting material to manufacture a manhole lower lid ; And arranging a manhole upper lid prepared in advance in the manhole lower lid, and then joining the lashes with each other to manufacture the manhole lid.
This makes it easier to manufacture a core for a hollow part in a mold making step without preparing a mold for an upper mold and a lower mold separately, and a thread corresponding to a thread bolt is formed in a coupling hole of a manhole upper lid and a manhole lower lid The integrated casting can be obtained, and the post-processing can be simplified. Thus, it is possible to produce a cast product having a desired shape, minimize the defective product, shorten the production time, and improve the productivity. Further, since the manhole upper lid and the manhole lower lid are combined with each other by the bolts of the right screw, it becomes difficult to open and close in addition to the occupant, thereby enhancing the security of manhole opening and closing.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an integrated manhole cover using an evaporation model method,

The present invention relates to a method for manufacturing a manhole cover, and more particularly, to a method for manufacturing an integrated manhole cover using a destructive modeling method.

In general, a manhole is a hole made to allow a person to enter the underground on the road surface. It is a facility that enables access to machinery and people for maintenance and inspection of underground wiring and sewage, A manhole lower lid, and a seating jaw is formed on an inner periphery of the manhole lower lid to seat the manhole upper lid.

FIG. 4 is a perspective view showing a conventional manhole lower lid, and FIG. 5 is a sectional view showing a conventional manhole lower lid.

4 and 5, the inner surface of the manhole lower lid is formed to have a predetermined diameter so as to insert the lid of the manhole. The inner surface of the manhole lower lid is formed as a concentric circle, The flange b is formed relatively wide and the engagement step d is formed concentrically in the middle of the inner peripheral surface and the outer peripheral surface of the flange b is relatively wide and the upper end reinforcing jaw and a triangular reinforcing rib c protrudes in the longitudinal direction from the lower end flange b to the middle of the outer peripheral surface at a predetermined angle interval along the outer peripheral surface.

Conventionally, a mold for casting a manhole cover is formed by compressing molding sand at a high temperature and a high pressure by using a core disposed between an upper mold and a lower mold by an outer circumference or another process, .

However, these conventional methods have a problem in that manhole covers are formed by upper and lower molds and the divided cores are disposed between upper and lower molds, resulting in an increase in production cost, complicated casting process, and increased casting time .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method of manufacturing a mold, which does not separately provide a mold for a top mold and a bottom mold, It is possible to eliminate the inconvenience of inserting a core for a hollow part or inserting a core in the casting step and to provide a bolt connection hole for a bolt connection between a manhole lower lid and a manhole upper lid. In order to simplify the post-machining step for thread cutting, it is possible to produce the casting product of desired shape, the product defect is minimized, and the post-processing step is simplified, And to provide a manhole cover capable of shortening the productivity and improving productivity .

In order to accomplish the above object, a method of manufacturing a manhole cover for simplifying a manufacturing process using a casting method using a loss modeling method according to an embodiment of the present invention includes the steps of: A method of manufacturing a molded body, the method comprising the steps of: preparing a model; inserting and removing the bolt from the disappearing model to form a coupling hole having a screw thread into which the bolt can be inserted; A step of coating and drying the graphite material on the molding material and the disappearance passages which are lost after being injected into the disappearing model material and the disappearing model material are fixed to the molding material in the casting mold; The molding sand is further inserted so that the upper end of the disappearance passage is exposed, A step of removing the air to firmly squeeze the foundry sand; and injecting the sludge into the upper part of the exposed sludge passage so that the sludge disappears and the sludge is replaced with the sludge model, A step of forming a casting by curing the casting, and separating the casting from the casting, and finishing the separated casting to complete the manufacture of a manhole lower lid; And arranging a manhole upper lid prepared in advance in the manhole lower lid, and then joining the lashes with each other to manufacture the manhole lid.

The coupling hole may be a coupling hole having a polygonal thread of a right-hand thread, and the polygonal bolt may have a right-angle thread of a right-hand thread for forming the coupling hole.

In addition, the step of tightening the insert may insert the foundry sand into the joint hole to prevent the thread of the right screw of the right screw from being deformed by the insert injected in the step of replacing the insert.

This makes it easier to manufacture a core for a hollow part in a mold making step without preparing a mold for an upper mold and a lower mold separately, and a thread corresponding to a thread bolt is formed in a coupling hole of a manhole upper lid and a manhole lower lid The integrated casting can be obtained and the post-processing can be simplified. Therefore, it is possible to produce excellent casting products having desired shapes, to minimize the product defects, to shorten the production time, and to improve the productivity.

1 is a flow chart of a manhole cover manufacturing method using a disappearance modeling method according to an embodiment of the present invention;
FIGS. 2A to 2H are schematic views for explaining steps of a manhole bottom lid manufacturing method using a disappearance modeling method according to an embodiment of the present invention; FIGS.
FIG. 3 is a combined state view showing a right-hand screw thread bolt coupling of a manhole upper lid and a manhole lower lid according to an embodiment of the present invention,
4 is a perspective view showing a conventional manhole lower lid,
5 is a cross-sectional view showing a conventional manhole lower lid,

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a flowchart of a manhole cover manufacturing method using a disappearance modeling method according to an embodiment of the present invention.

The present invention relates to a method for manufacturing a manhole cover using a casting method using a disappearing model, in which a mortar is introduced into a mortar mold formed of expanded polystyrene (EPS) or polymethacrylite (PMMA) Thereby making it possible to produce cast products having required mechanical properties and shapes.

As shown in FIG. 1, a method for manufacturing a manhole lower lid through a casting method using a disappearing model includes steps S10, S20, A mold compaction step S40, a filling compaction step S50, a dross injection step S60, a cement hardening step S70, a separation step S80, and a casting completion step S90.

FIGS. 2A to 2H are schematic views illustrating respective steps of a manhole cover manufacturing method using a disappearance modeling method according to an embodiment of the present invention.

2A, in the destructive model building step S10, the manhole cover is polished with expanded polystyrene (EPS) or polymethacrylite (PMMA) using a model mold, To prepare a manhole cover-shaped casting at the time of disappearance. Therefore, the shape of the manhole cover is changed according to the shape of the mold in the destruction modeling step (S10), so that the manhole cover having various shapes set according to the purpose can be produced.

As shown in FIG. 2B, the joining hole forming step S20 is a step of forming an engaging hole 185 having a nut-like shape corresponding to the bolt 180 provided in the manhole upper lid in the manhole lower lid. A space is formed by inserting a predetermined angle bolt 180 into a portion where the upper lid is seated and fitted to the body 100. The space in which the bolt 180 is engaged is formed in a space The space is filled by the molding sand 500 so that the angular thread is not deformed when the molten metal is injected in the molten metal injection step S60 and the dimensions of the angular bolt 180 are adjusted in consideration of the contraction caused by the high temperature, The coupling hole 185 is formed with a predetermined tolerance.

By forming the hollow portion by inserting the core into the destructive model body 100, it is easier to manufacture the shape than by forming the hollow portion by inserting the core at the time of casting, and the production cost and production time can be reduced.

As shown in FIG. 2C, the graphite material applied on the outer surface of the disappearance model is buried in a molding sand, which will be described later, and then when the molten material is injected, It has the possibility of collapsing because it does not have the strength to maintain the shape before it is formed. Therefore, it plays the role of supporting the shape of the casting and discharging the decomposition material of the disappearing model produced in the liquid phase and the vapor phase.

Accordingly, in the re-coating and drying step S30, the body of the disappearing model body 100 is immersed in a storage tank containing the drawing material to apply the molding material to the entire outer surface of the body of the disappearing molding body. Then, the graphic material coated on the entire outer surface of the disappearing model body 100 is dried at the shade to form the graphic material layer 160 on the entire outer surface of the destructible model body 100.

As shown in FIG. 2d, the disappearance model placing step S40 includes a casting mold 200 having a vacuum suction port 300 and a vacuum suction port 300 formed on one side of the inner bottom and four walls. Then, the foundry sand (500) is filled at a predetermined height on the bottom of the casting mold (200). Thereafter, the casting mold 200 is vibrated by the vibrator 400 so that the foundry sand 500 is stuck to each other by vibration and hardened and flattened. Thereafter, the disappearing model body 100 is placed on the foundry sand 500 of the bottom so as to be balanced. Then, the destruction passageway (not shown) protruding vertically higher than the destructive model body 100, 120 are hermetically sealed to the gravure model main body 100, thereby binding them. By maintaining the airtightness of the elimination passage 120 into which the dirt is injected, foreign matter such as the molding sand 500 can be prevented from penetrating into the destructive model body 100, thereby improving homogeneity of the manhole cover and minimizing defects .

As shown in FIG. 2E, the filling compaction step S50 is performed in such a manner that the recessed model body 100 is higher than the disappearing model body 100 and has a lower height than the disappearance passage 120 in a state where the recessed model body 100 is placed in the casting mold 200 The casting mold 500 is filled in the casting mold 200. The upper end of the elimination passage 120 is exposed to the upper side of the molding sand 500 at the upper portion of the casting mold 200 and then the vacuum suction port formed at the lower portion of the casting box 200, The vacuum pump 320 is operated on the casting mold 300 to firmly squeeze the molding sand 500 filled in the casting mold 200.

In the filling compaction step S50, when the molding sand 500 is inserted into the coupling hole 185, the core thread is prevented from being deformed by the dross injected in the dross injection step S60, which will be described later, .

As shown in FIG. 2F, the molten metal injection step S60 is a step of injecting molten metal into the molten metal injection unit 140 at the upper end of the elimination passageway 120, which is exposed above the molding sand 500, in a state in which the vacuum pump 320 is continuously operated, And the waste material is injected into the space occupied by the body of the destruction molding body 100 while the entire body of the destruction molding body 100 buried in the molding sand 500 is connected to the elimination passage 120 and the elimination passage 120 And the step of replacing the waste model body 100 with the waste.

As shown in FIG. 2F, the cement hardening step S70 includes not only during the filling step S50, during the sludge injection step S60, but also after the sludge injection step S60 is completed, And the combustion gas generated when the disappearance passage 120 and the disappearing model body 100 are destroyed by the molten metal is discharged through the mold material layer 160 by continuously operating the vacuum pump 320 until the exhaustion passageway 120 and the destruction-

2G, the separating step S80 is a step of discharging the molding sand 500 of the casting mold 200 and separating the molding sand 500 and the casting 600 from the casting mold 200, 500) is cooled and recycled again in the lost model resting step (S40).

As shown in FIG. 2H, the casting completion step S90 is a step of completing the casting 600 by a post-treatment operation for removing unnecessary portions attached to the cast 600 separated and transferred in the separation step S80.

The method of manufacturing a manhole cover according to the present invention is not required to have a separate mold such as a top mold and a bottom mold, and a core for a hollow portion such as the coupling hole 185 is provided in the mold making step, Thereby facilitating manufacture.

Generally, since the manhole cover is coupled to the manhole upper lid and the manhole lower lid by bolts, a bolt is coupled to the manhole upper lid, and a nut-like maleic acid corresponding to the bolt is formed on the manhole lower lid. Since threads that are vulnerable to strength and hardness are often crushed by the frequent opening and closing of the manhole cover, it is not necessary to use a casting type, but rather threaded or cut threads into the coupling holes 185 of the lower manhole cover, Has been commonly used.

Therefore, in the present invention, a manhole lower lid and a female thread are integrally manufactured using the disappearing model method, and a thread which is inevitably fragile with respect to strength and hardness is inserted into the joint hole 185 of the thread angle bolt 180 and the corresponding thread thread 185 ), It is possible to improve the openability of the manhole and to reduce the production period and the production unit cost, and to improve the productivity.

Since the engaging holes 185 of the manhole lower lid are formed by using the hexagonal bolts 180 as cores, the cores for the hollow portions are provided in the mold making step without separately providing the upper and lower molds And a screw thread corresponding to the thread bolt 180 is provided on the coupling hole 185 of the manhole upper lid and the manhole lower lid. Thus, the integrated casting can be obtained and the post-processing can be simplified, Production is possible, product defects are minimized, production time can be shortened and productivity can be improved. Further, since the manhole upper lid and the manhole lower lid are combined with each other by the bolts of the right screw, it becomes difficult to open and close in addition to the occupant, thereby enhancing the security of manhole opening and closing.

3 is a combined state view showing a right-hand screw thread bolt coupling of a manhole upper lid and a manhole lower lid according to an embodiment of the present invention.

As shown in FIG. 3, a mountain bolt having a right-hand thread is provided to form a mountain horn or a mountain on the corresponding engagement hole 185, so that the manhole upper lid and the manhole lower lid are engaged with the right- . Accordingly, since the bolt thread is increased in openness in the form of an angular thread, and the user who uses the left-hand thread generally uses the right-hand screw, the security of the opening and closing of the manhole can be enhanced .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

100: main body 120:
140: molten metal injection part 160:
180: string bolt 185: engaging hole
200: Spout 300: Vacuum inlet
320: Vacuum pump 340: Vacuum hose
400: Vibrator 500: foundry sand
600: Casting

Claims

A method for manufacturing a manhole cover using a casting method using a destructive model method,
Fabricating a mold made of a styrofoam having the same size as the manhole cover by using a model mold;
Inserting the bolts into the recessed mold and removing the bolts, thereby forming a coupling hole having a screw thread into which the bolt can be inserted;
Immersing the disappearing molding material into a mold material to apply the mold material to the mold material and drying the mold material;
Placing the waste disappearance passage to be fixed to the foundry sand in the casting mold;
Further injecting the foundry sand so that the disappearance model is buried and the upper end of the disappearance passage is exposed, and removing the air in the foundry sand to firmly squeeze the foundry sand;
Injecting the molten metal into the upper part of the exposed passage to allow the molten metal to displace the molten metal and the molten metal while the molten metal disappears;
Curing the molten material to form a casting;
Separating the casting from the foundry sand;
Finishing the separated casting to complete the manufacture of the manhole bottom lid; And
The method comprising: placing a manhole upper lid prepared in advance in a manhole lower lid, and bonding the manhole upper lid to the manhole lid with each other;

The method according to claim 1,
The coupling hole
A joint ball having an angular thread of a right screw,
The above-
And a right-angle threaded thread for forming the coupling hole.

3. The method of claim 2,
The tightening step may comprise:
Wherein the core thread is inserted into the engaging hole so that core threads of the right screw are not deformed by the molten metal injected in the step of inserting the molding sand into the engaging hole.