JPS63143B2 - - Google Patents

Description

[Detailed description of the invention] a. Industrial application field The present invention is arranged in a core box,
When in contact with the inner wall of the core box,
Used to make casting cores from sand for cores using compressed air, equipped with a removal member that can be removed from the core box after filling the core box with sand for cores. Regarding the core box.

B. PRIOR ART Core boxes known in the past are mainly made of aluminum for weight-saving reasons, but the removable removal parts are often made of bronze. Other materials used include plastic or wood.
In both cases, materials with low wear resistance are used. However, while using the core box,
The core box is in constant contact with the highly abrasive sand. The abrasive effects that occur when blowing or filling sand with compressed air are caused, among other things, by the fact that the compressed air hits unsealed areas along with the sand carried by the compressed air. Acceleration occurs when the hole there grows larger in a short period of time. This danger appears particularly at the abutment surfaces of the removal member. That is, the gap is initially very narrow, but gradually widens into a slit, through which compressed air and sand flow.

Such defects can be recognized at a very early stage. That is, the finished core exhibits defects in the form of porous sand moldings and broken edges where the compressed air has passed. Since such defects must not be transferred to the cast product, expensive manual repair of the core is required. Moreover, the core box wears out rapidly.

c. Problems to be Solved by the Invention Therefore, an object of the present invention is to provide a core box configured to prevent the formation of slits on the contact surface of the removable member. .

d Means and action for solving the problem In order to achieve the above purpose, in the first type of core box, there is a gap between the inner wall surface of the core box and the contact surface of the removable member. 1 made of elastic material that performs an adjustment function to prevent
According to the invention, a core box has been proposed which is characterized in that it is provided with one or more sealing members.

The sealing member according to the present invention can be embodied in various forms. For example, a molded body having an elastic surface matching the contour of the inner wall surface of the core box may be placed in the core box. The inner wall surface of the core box itself may be provided with an elastic coating layer. Also,
An elastic coating layer may be provided on the contact surface of the detachable member. A feature of the two embodiments mentioned at the outset is that the inner wall surface of the core box is protected from wear. In the case of the embodiments described below, the present invention can be easily applied to core boxes currently in use.

e Embodiments The present invention will now be described in detail with reference to the accompanying drawings, which illustrate embodiments of the invention.

The cores made from the core boxes shown in FIGS. 1 and 2 are the same cores used in casting impellers for circulation pumps.

The core box shown in FIG.
It consists of a lid 2 and a plurality of removal members 3 distributed at equal intervals around the round core box, and the removal members 3 are provided with insertion ribs 4. The insertion rib 4 serves to fix the removal member 3 whose upper and lower end surfaces are brought into contact with the inner wall surface of the core box.

In order to prevent compressed air and mold sand from moving from one side of the removal member 3 to the other while blowing or filling the cavity 5 of the core box with core sand, The contact surface on the end face side of the removal member 3 must be in tight contact with the inner wall surfaces of the main body 1 and the lid 2. The rapid movement of air creates a porous molding area on the opposite side and the edge of the core adjacent to the removal member 3 is prone to collapse. Moreover, due to the grinding action of the core sand, the gap through which air passes gradually widens. This accelerates the wear of the core box and increases the defects that appear in the finished core. This defect can only be repaired by expensive manual methods.

The core box according to the invention shown in FIG. 2 basically consists of the above-mentioned members shown in FIG. ing. On the inner walls of the body 6 and the lid 7, a vulcanized covering layer 9 made of an elastic material is provided in the area of the removal member 8.

When assembling the core box, the member 8 to be removed is pushed into the covering layer 9 to some extent due to the compressibility of the covering layer 9. This amount of pushing is sufficient to ensure a complete sealing effect over the entire contact surface of the removal member 8. Thus, while filling the cavity 5 with sand, the compressed air and the core sand pass through the gaps formed on both end faces of the removal member 8, which may cause defects in the finished core. problems can be avoided.

The removal element 8 is provided with plug-in ribs 10, each of which is provided with a guide 11 adjacent to the removal element 8. Guide 1
The length f of 1 is set shorter than the length g of the portion of the insertion rib 10 that protrudes from the main body 6. Thanks to the above-described configuration, when removing the release member 8 from the core, the upward pressure exerted on the underside 12 of the insert rib 10 exceeds the compaction force, so that the insert rib 10 can be pushed out of the main body.

An elastic packing 13 additionally provided in the main body 6 surrounds the insertion rib 10 at the lower end of the main body 6, so that it is supplementary to prevent leakage from the cavity 5 to the outside of the core box. It is possible to perform sealing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional core box equipped with a removable member. FIG. 2 is a sectional view of the core box according to the present invention. 1... Main body, 2... Lid, 3... Removable member, 4... Insert rib, 5... Blank space, 6... Main body, 7... Lid, 8... Removable member, 9...
Covering layer, 10... Insert rib, 11... Guide, 1
2... Lower side of insertion rib, 13... Packing.

Claims (1)

[Scope of Claims] 1. The sand is placed in the core box and is in contact with the inner wall surface of the core box, and is removed from the core box after the sand for the core is filled in the core box. A core box used for making a casting core from core sand using compressed air and equipped with a removable member, the inner wall surfaces of the core boxes 6 and 7 A core box characterized in that it is equipped with one or more sealing members 9 made of an elastic material, which perform the adjustment function so that no gap is created between the contact surface of the removal member 8 and the contact surface of the removal member 8. 2. A core box according to claim 1, in which the sealing member is made of one or more molded materials having an elastic surface that matches the contour of the inner wall surface of the core box. A core box featuring the following. 3. The core box according to claim 1, wherein the sealing member comprises a coating layer attached to the inner wall surface of the core box. 4. A core box according to claim 1 or 3, wherein the core box is made of a covering layer 9 of an elastic material or an elastic material adhered to the inner wall surface of the core boxes 6, 7. A core box characterized by being equipped with a coating layer which is vulcanized. 5. A core box according to claim 1 or 3, wherein the core box has an elastic material attached to the inner wall surface of the core box by pouring, spraying or other suitable coating method. A core box characterized by comprising a covering layer of material. 6. The core box according to claim 1, characterized in that a sealing material is provided on the contact surface of the removable member. 7. The core box according to claim 1 or 6, in which the abutting surfaces of the removable members each include a covering layer of an adhesively bonded elastic material or a covering layer obtained by vulcanizing the elastic material. The core box is characterized by the following: 8. The core box according to claim 1 or 6, preferably in which the sealing band recessed in the removal member and removably installed in the groove is removable. A core box characterized by being provided on a contact surface of a member. 9. The core box according to any one of claims 1 to 8, wherein the removable member is provided with an insertion rib that is inserted through the bottom of the core box and serves as a fixing member. , each plug-in rib 10 is provided with a guide 11 adjacent to the removal member 8, which guide 11 follows a conically extending portion and has a length of the portion projecting from the core box 6. A core box characterized in that g is set larger than the length f of the guide 11. 10 The core box according to claim 1 or 9, wherein the elastic packing 13 surrounds the conical portion of each insertion rib 10.
are provided within the walls of the core boxes 6 and 7.