Method of removing molded article and apparatus for same

A method of removing a molded article, which makes it possible to remove easily said molded article without causing deformation and damages thereto and an apparatus for same. The method comprises removing a sand core W which is obtained using a sand core forming mold 12 comprising a fixed and movable molds 21 and 31 from a sand core forming mold 12 by a separating movable mold 31 from the fixed mold 21 to perform a mold opening. The fixed mold 21 is provided with a fixed mold side core 23 having a front end face 23a forming a part of a first molding face 22, which is extendable and retractable in a mold opening direction A1. The movable mold 31 is provided with a movable mold side core 33 having a front end face 33a forming a part of a second molding face 32, which is extendable and retractable in a mold opening direction A1. The relation in which the sand core W is held between both cores 23 and 33 is kept by extending both cores 23 and 33 in a mold opening direction A1.

FIELD OF THE INVENTION

The present invention relates to a method of removing a molded article which is obtained using a forming mold therefrom by conducting a mold opening, and a molding apparatus for same.

BACKGROUND OF THE INVENTION

Various molded articles have heretofore been produced by using molding apparatus each comprising fixed and movable molds. Specifically, a molded article is produced by injecting a molding material into a molding space (cavity) defined by fixed and movable molds. Then, the resultant molded article is removed from the cavity of the forming mold by conducting a mold opening to separate the movable and fixed molds. Since the molded article is adhered to the molding face (cavity face) of at least one of the molds, removing thereof is often difficult. Accordingly, methods of separating and dropping the molded article from the molding face by inserting an eject pin and the like against the molded article in the course of the mold opening have been proposed. Methods of separating the molded article from the molding face and carrying it by gripping and sucking it with devoted carrying apparatus have also been proposed. Methods of separating the molded article from the molding face by inserting an eject pin and the like in the course of the mold opening and thereafter sucking the separated molded article to a carrying unit have been proposed (refer to Patent document 1).

SUMMARY OF THE DISCLOSURE

The above-mentioned prior art removing methods using an eject pin have a problem in that the molded article is liable to be subjected to deformation and/or damage due to the shock on dropping thereof. The prior art removing method using the carrying unit has a problem in that removal thereof may be difficult depending upon the shape thereof. If the molded article which is difficult to remove is forcedly removed, deformation and damage are liable to be caused on the molded article.

The above-mentioned problems are remarkable if the molded article is fragile (for example, the molded article is formed of sand and the like).

The present invention has been made in view of the above-mentioned problems. It is an object to provide a method which enables molded articles to be easily removed without causing any deformation and/or damage of the molded article. It is another object of the present invention to provide a molding apparatus which is preferable to perform the above-mentioned excellent removing method.

According to Claim1in a first aspect of the present invention, there is provided a method of removing a molded article which can be obtained by using first and second molds having a first molding face and a second molding face, respectively, by conducting mold opening for separating the first and second molds from each other. The method comprises: providing a first movable insert member having a front end face forming a part of the first molding face so that the first movable insert member is extendable into or retractable from the first mold; providing a second movable insert member having a front end face forming a part of the second molding face so that the second movable insert member is extendable into or retractable from the second mold; and keeping the molded article to be held between both movable insert members by extending both of the movable insert members relative to the molds in a mold opening direction when the molds are opened.

In accordance with the method of Claim1, the molded article can be easily removed from the first and second molding faces of the first and second molds by extending the first and second insert members in a mold opening direction upon opening of the mold. Dropping of the molded article can be prevented due to the fact that the molded article is kept to be held between the first and second movable insert members. Even if the molded article is fragile, the molded article can be easily removed from the forming mold without causing any deformation and/or damage thereof.

Specifically, the first and second movable insert members may include a core to form the molded article with a concave or convex, also an eject pin and the like not intended to form the molded article with a concave or convex. If the movable insert member is a core, the molded article is more stably held, so that dropping of the molded article can be positively prevented. The number of the first and second movable insert members is not particularly limited, and may be one or plural.

When both movable insert members are extended in mold opening directions, it is preferable to keep the separation distance between the front end faces of both movable insert members at a constant distance. This enables the front end faces of both movable insert members to be constantly in contact with the surface of the molded article until the mold opening is completed. Thus, the molded article is more stably held, so that the molded article can be positively prevented from being dropped.

According to Claim2, there is provided a method of removing a molded article according to the first aspect, wherein the lower side of the molded article is supported by a molded article receiving jig and the molded article is released from the both movable insert members by separating both movable insert members from each other under this condition.

In accordance with the invention as set forth in Claim2, shock is hardly applied to the molded article even when the molded article is transferred to the molded article receiving jig from both movable insert members since the lower side of the molded article has been already supported by the molded article receiving jig. It is not necessary to grip the molded article on transferring if the molded article receiving jig which supports the lower side of the molded article is used. As a result, deformation and/or damage of the molded article can be positively prevented from occurring.

It is preferable that the upper face of the molded article receiving jig has a form which conforms to the surface contour (profile) of the lower side of the molded article. In this case, chipping of the molded article can be prevented more positively.

According to the method as defined in Claim3, when the molds are opened, the first movable insert member telescopically extends relative to the first mold and the second movable insert member telescopically extends relative to the second mold.

According to the method as defined in Claim4, when the molds are opened, at least one of the first and second movable insert members extends and retracts parallel to the mold opening direction.

According to the method as defined in Claim5, when the molds are opened, a distance between the front end face of the first movable insert member and the front end face of the second movable insert member is kept constant.

In a second aspect of the present invention, according to Claim6, there is provided a molding apparatus including a forming mold assembly comprising first and second molds having a first molding face and a second molding face, respectively, in which the forming mold assembly is opened by separating the first and second molds from each other. The apparatus comprises: a first movable insert member provided on the first mold, the insert member having a front end face forming a part of the first mold, the insert member being extendable from or retractable in a mold opening direction; and a second movable insert member provided on the second mold, having a front end face forming a part of the second mold, the insert member being extendable from or retractable in a mold opening direction; provided that the both movable insert members are structured to be capable of simultaneously performing an extending operation on opening of the molds.

In the apparatus as set forth in Claim6, the first and second movable insert members are extended from the first and second molding faces of the first and second molds, respectively, upon opening of the mold. Therefore, the first movable insert member is not moved away from the second movable insert member even at opening of the mold. It is possible to keep holding of the molded article during the opening process of the mold. Use of this molding apparatus makes it possible to conduct the method of removing the molded article easily without causing any deformation and/or damage.

According to Claim7, in a molding apparatus as defined in Claim6, the apparatus further comprises a molded article receiving jig which is retracted to a position below the first and second molds when the mold is closed and is elevated to a position where it supports the lower side of the molded article when the mold is opened.

Since the molded article receiving jig is retracted to a position below the first and second molds at closing of the mold in the apparatus as set forth in Claim7, interference between the first and second molds and the molded article receiving jig can be prevented. When the mold is opened, the molded article receiving jig is elevated to a predetermined position where it positively supports the lower side of the molded article and receives it. The molded article receiving jig may be configured to carry the received article to another position.

According to Claim8, there is provided a molding apparatus as defined in Claim6, wherein the apparatus comprises a first stop member which is extended or retracted together with the first movable insert member, and a second stop member which is extended or retracted together with the second movable insert member; and in that both stop members are configured so that an abutting relationship between the front end portions of the first and second stop members is kept until the mold opening is completed.

In the apparatus according to Claim8, approaching of the front end faces of both movable insert members to each other can be prevented due to the fact that the abutting relationship between the front end portions of both stop members is kept until mold opening is completed. Therefore, deformation and/or damage of the molded article due to excessive extension of both movable insert members can be prevented.

According to a third aspect of the present invention, there is provided a method of producing a molded article by removing a molded article which is obtained by using a first mold having a first molding face and a second mold having a second molding face by conducting mold opening for separating the first and second molds from each other. The method comprises: providing a cavity by the first and second molds at a closed state and a first movable insert member having an end face forming a part of the first molding face and a second movable insert member having an end face forming a part of the second molding face, charging a mold material into the cavity for molding, and opening the molds for separating the first and second molds from each other while maintaining a state where the molded article is supported by the first and second movable insert members, whereupon the molded article can be removed.

According to the third aspect, the molded article is prevented from dropping by maintaining the state where the molded article is retained (or held) between the first and second insert members upon opening of the molds. Even if the molded article is fragile, the molded article can be easily removed from the forming mold without causing any deformation and/or damage thereof.

According to the third aspect, the method further comprises: supporting a bottom side of the molded article by a supporting jig when the molds are opened, while the molded article is supported by the first and second movable insert members, and releasing the molded article from both the movable insert members by supporting both the movable insert members from each other in the state that the molded article is supported by the supporting jig.

According to the third aspect, during the opening of the molds, the first movable insert member extends relative to the first mold and the second movable insert member extends relative to the second mold.

According to the third aspect, during the opening of the molds, at least one of the first and second movable insert members extends parallel to a direction of opening and closing of the molds.

According to the third aspect, during the opening of the molds, the end face of the first movable insert member and the end face of the second movable insert member, i.e., abutting faces of both the movable insert members to the molded article, are kept at a constant separated distance.

According to a fourth aspect of the present invention, there is provided a molding apparatus comprising a mold assembly having a first mold with a first molding face and a second mold with a second molding face, in which the molds are opened by separating the first and second molds from each other. The apparatus further comprises: a first movable insert member that is extendable and retractable along a direction of opening and closing of the molds, the first movable insert member being provided in the first mold and having an end face forming a part of the first molding face, a second movable insert member that is extendable and retractable along a direction of opening and closing of the molds, the second movable insert member being provided in the second mold and having an end face forming a part of the second molding face, a mold driving unit for displacing at least one of the first and second molds, and a driving unit for displacing at least one of the first and second movable insert members relative to the first and second molds.

In the fourth aspect, the molded article is supported by both the movable insert members during opening of the molds.

According to the fourth aspect, the molded article can be retained in a supported state between the first and second insert members by means of the driving unit for the first and second movable insert members. This allows easy removal of the molded articles without deformation or fracture.

In the fourth aspect, the driving unit for the movable insert members comprises a device for extending the first movable insert member relative to the first mold, and a device for extending the second movable insert member relative to the second mold.

Also in the fourth aspect, the driving unit for the movable insert members comprises a device for extending and retracting at least one of the first and second movable insert members in parallel with the direction of opening and closing of the molds relative to the first or second mold.

Also in the fourth aspect, the molding apparatus further comprises a supporting jig for supporting the molded article, the jig assuring a retracted position below the first and second molds upon closing the molds, and an elevated position to support a bottom side of the molded article upon opening the molds.

Also in the fourth aspect, the first and second insert members comprise a stopper member or members or a shape that can keep constant a distance between the first and second movable insert members so as to prevent unexpected nearing each other when the molds are opened.

Also in the fourth aspect, the first mold is a fixed mold, and the second mold is a movable mold, the mold driving unit comprises a mold opening/closing mechanism for displacing the second mold, and the driving unit for the movable insert members comprising: an insert member driving device, arranged at the first mold, for extending the first movable insert member from the first mold by moving the first movable insert member in a direction opposite to the first mold when the molds are opened, and an insert member driving device, arranged at the second mold, for extending the second movable insert member from the second mold when the molds are opened.

As mentioned in detail, a method which can easily remove the molded article without any deformation and/or damage can be provided in accordance with the present invention. A molding apparatus which is preferable to conduct the above-mentioned excellent removing method can be provided in accordance with the present invention.

PREFERRED EMBODIMENTS OF THE INVENTION

An embodiment in which the present invention is embodied will now be described in detail with reference toFIGS. 1 through 6.

A sand core molding apparatus11(molding apparatus) shown inFIGS. 1 and 2is an apparatus to mold a sand core W as a molded article by charging sand into a molding space (cavity) within sand core molding mold12(forming mold) comprising a fixed mold21(first mold) and a movable mold31(second mold).

The fixed mold21and a cylinder25for driving a fixed mold side core (insert member driving unit) are secured on a fixed mold side base11aof the sand core molding apparatus11. A plate26for a first cylinder is secured to the cylinder25for driving the fixed mold side core. Base ends of first connecting plates27are connected to both sides of the plate26for the first cylinder. The front ends of the first connecting plates27are connected to the rear end faces of the fixed mold21. The cylinder25for driving the fixed mold side core comprises a rod25awhich extends or retracts in a right or left direction inFIG. 1.

As shown inFIGS. 1 and 2, a molding opening and closing cylinder (mold driving unit)13which conducts mold closing (mold clamping) by moving the movable mold31toward the fixed mold21or bringing them into a contact, and mold opening by moving the movable mold31away from the fixed mold21is secured on a movable mold side base11bof the sand core molding apparatus11. The mold opening and closing cylinder13comprises a rod13afor moving the movable mold31in a right or left direction inFIG. 1. A pair of rails14extending in a mold opening direction A1of the movable mold31is provided on the movable mold side base11b.A slider31awhich is provided under the movable mold31is guided on and along the rails14, so that the movable mold31is movable in a mold opening direction A1.

Said sand core forming mold12is opened due to the fact that the movable mold31is moved in a mold opening direction A1by the mold opening and closing cylinder13so that it is moved away from the fixed mold21. Parting (splitting) faces12a,12bof the sand core molding molds (mold assembly)12are perpendicular to the mold opening direction A1. The parting face12aon the side of the fixed mold21is parallel with the parting face12bon the side of the movable mold31. The parting faces12aand12bmay not be perpendicular to the mold opening direction A1. The fixed mold21has a first molding face22in the parting face12aand the movable mold31has a second molding face32in the parting face12b.These first and second molding faces22and32form a cavity of the sand core molding mold12, when the mold is closed.

As shown inFIGS. 1 and 2, the fixed mold21is provided with a fixed mold side core23as a first movable insert member and the movable mold31is provided with a movable mold side core33as a second movable insert member. The fixed and movable mold side cores23and33, respectively, are capable of forming a concave or convex on the sand core W as a molded article.

A first core plate23bwhich is biased upon the rod25aof the cylinder25for driving the fixed mold side core is secured to the base end side of the fixed mold side core (insert member)23. The front end portion of the fixed mold side core23is inserted into the fixed mold21upon closing of the mold and its front end face23aforms a part of the first molding face22. The front end portion of the fixed mold side core23is extended beyond the first molding face22due to the fact that the first core plate23bis biased by the rod25awhen the mold is opened (refer toFIG. 3). The fixed mold side core23is extendable or retractable in parallel with a mold opening direction A1.

As shown inFIGS. 1 and 2, a second core plate33bis secured to the base end side of the movable mold side core (insert member)33. The second core plate33bis moved by the extension or retraction of a rod35awhich is provided on a cylinder35(insert member driving unit) for driving the movable mold side core. A plate36for the second cylinder which is moved together with the rod13aof the mold opening and closing cylinder is secured to the cylinder35for driving the movable mold side core. The base ends of second connecting plates37are connected to bath sides of the plate36for the second cylinder. The front ends of both second connecting plates37are connected to the movable mold31.

The front end portion of the movable mold side core (insert member)33is inserted into the movable mold31on closing of the mold and its front end face33aforms a part of the second molding face32. The front end portion of the movable mold side core33is extended beyond the second molding face32due to the fact that the second core plate33bis biased by the rod35aof the cylinder35for driving the movable mold side core on opening of the mold (refer toFIG. 3). At this time, the front end face23aof the fixed mold side core23and the front end face33aof the movable mold side core33keep an abut condition with the sand core W until the mold opening is completed. The sand core W is kept to be held by the fixed mold side core23and the movable mold side core33. The movable mold side core33can be extended or retracted in parallel with the mold opening direction A1.

As shown inFIGS. 1 and 2, two first stop pins24(first stop members) are connected to each of both sides of the first core plate23b.Each of the first stop pins24extends through the fixed mold21in the same direction (that is, the right or left direction inFIG. 1) by the same length. Two second stop pins34(second stop members) are connected to each of both sides of the second core plate33b.Each of the second stop pins34extends through the movable mold31in the same direction (that is, the right or left direction inFIG. 1) by the same length. The front end of the second stop pin34can abut upon the front end of the first stop pin24. The first stop pin24may extend beyond or retract from the parting face12of the fixed mold21in an interlocking manner with the extension or retraction of the fixed mold side core23. The second stop pin34may extend beyond or retract from the parting face12bof the movable mold31in an interlocking manner with the extension and retraction of the movable mold side core33. The second stop pin34is capable to guide the movable mold31to an appropriate position on closing of the mold. The front end portions of the first and second stop pins24and34are structured to keep the abutting condition therebetween until the completion of the mold opening. This keeps the separation distance between the front end face23aof the fixed mold side core23and the front end face33aof the movable mold side core33constant during the mold opening.

As shown inFIG. 2, the sand core molding apparatus11comprises a molded article receiving jig (supporting jig)41for receiving the sand core W. The molded article receiving jig41is stepped on the top face (supporting face41a) thereof so that it conforms to the surface contour (profile) of the lower face W1of the sand core W to be supported. The molded article receiving jig41can be retracted to a position below the fixed mold21and the movable mold31by a lifting mechanism (not shown) on closing of the mold. The molded article receiving jig41can be elevated to a predetermined position where it supports the lower face WI of the sand core W on completion of the mold opening (refer toFIG. 4).

Now, a process for molding the sand core W using the sand core molding apparatus11will be described.

The cavity is defined by the second molding face32of the movable mold31, the first molding face22of the fixed mold21, the front end face33aof the movable mold side core33and the front end face23aof the fixed mold side core23by fitting the movable mold31to the fixed mold21. Under this condition, the sand core W is formed by filling the cavity with sand (refer toFIGS. 1 and 2). In this case, the sand within cavity is compacted by at least one of the fixed mold side core23and the movable mold side core33.

A process for removing the molded sand core W from the sand core molding mold12will be described.

The movable mold31is moved from the fixed mold21in a mold opening direction A1at a predetermined speed from a mold closing condition shown inFIG. 2by driving the mold opening and closing cylinder (mold driving unit)13. Simultaneously with this, the front end portion of the movable mold side core33is extended from the second molding face32of the movable mold31by driving the cylinder35for driving the movable mold side core. This enables the front end face33aof the movable mold side core33to keep the abutting relationship between it and the one side of the sand core W. The front end portion of the fixed mold side core23is projected from the first molding face22of the fixed mold21by driving the cylinder25for driving the fixed mold side core. This enables the front end face23aof the fixed mold side core23to keep an abutting relationship between it and the other side of the sand core W. As a result, the sand core W is separated from the movable mold31and the fixed mold21and the sand core W is kept to be held between the movable mold side core33and the fixed mold side core23(refer toFIG. 3). In the present embodiment, the moving speed (V) of the movable mold31is equal to the sum of the extending speed (Va) of the fixed mold side core23and the extending speed (Vb) of the movable mold side core33. This enables the sand core W to be continuously held so that the sand core W can be prevented from dropping. The sand core W can be positively removed from the first and second molding faces22and32.

At this time, the front end portions of the first and second stop pins24and34keep the abutting relationship therebetween. This prevents further moving of the front end face23aof the fixed mold side core23which moves together with the first stop pin24toward the front end face33aof the movable mold side core33which moves together with the second stop pin34. Therefore, deformation and/or damage of the sand core W due to excessive extension of both insert members23and33can be prevented.

Then, the molded article receiving jig41which has been retracted below is elevated to a predetermined position where it supports the lower face W1of the sand core W in order to support the sand core W by the supporting face41aof the molded article receiving jig41(refer toFIG. 4). The sand core W is released from both insert members23and33by moving the movable mold side core33away from the fixed mold side core23under this condition so that the sand core W is transferred on the molded article receiving jig41(refer toFIG. 5). The recovery of the sand core W is enabled by lowering the molded article receiving jig41to a position below the fixed mold21and the movable mold31(refer toFIG. 6).

According to the present invention, the following effects can be provided.

(1) In the sand core molding apparatus11of the present invention, the sand core W can be easily separated from the first molding face22of the fixed mold21and the second molding face32of the movable mold31by extending the fixed mold side core23and the movable mold side core33in a mold opening direction Al on opening of the mold. Even in this case, an operation for extending the fixed mold side core23from the first molding face22is performed and an operation for extending the movable mold side core33from the second molding face32is performed upon opening of the mold. Therefore, dropping of the sand core W is prevented due to the fact that the fixed mold side core23is not separated from the movable mold side core33and the holding of the sand core W between the fixed mold side core23and the movable mold side core33is kept. Thus, the sand core W can be easily removed from the sand core forming mold12without causing any deformation and/or damage of the sand core W also in a case like the present invention the fragile sand core W is removed.

(2) In the present embodiment, the fixed mold side core23and the movable mold side core33are fitted to the convex or concave of the sand core W. Therefore, the sand core W is more stably held, so that dropping of the sand core W can be positively prevented on opening of the mold. In addition, since the supporting face41aof the molded article receiving jig41is stepped so that it conforms to the surface contour of the lower face W1of the sand core W, dropping of the sand core W can be prevented when the molded article receiving jig41receiving the sand core W and is lowered on opening of the mold. In this case, chipping of the edge portion of the sand core W can be prevented.

(3) In the present embodiment, the fixed mold side core (insert member)23and the movable mold side core (insert member)33are extendable or retractable in parallel with the mold opening direction A1. Therefore, since arrangement of both cores (insert members)23and33is easy, the sand core molding apparatus11of the present embodiment having both cores (insert members)23and33can be easily designed. Since the movable mold31, fixed mold side core23and the movable mold side core33are moved in parallel with the mold opening direction A1, the movable mold31can be moved simultaneously with the movement of both cores23and33. This makes the mold opening easy.

The embodiment of the present invention may be modified as follows:

In the foregoing embodiment, the first and second molds are formed as fixed and movable molds21and31, respectively. Both of the first and second molds may be formed as movable molds.

The embodiment in which the molded article is the sand core W has been described. The molded article may be a cast article (for example, aluminum die cast article) or a resin molded article. The molded article may be in any other shape.

In the foregoing embodiment, deformation and/or damage of the sand core W due to excessive extension of the fixed mold side core23and the movable mold side core33is prevented by the abutting relation between the front end portions of the first and second stop pins24and34, respectively.

In order to prevent the sand core W from being deformed or damaged, the front end face23aof the fixed mold side core23may abut on the front end portion of the second stop pin34or the front end face33aof the movable mold side core33may abut on the front end portion of the first stop pin24. Alternatively, the front end face23aof the fixed mold side core23may abut on the front end face33aof the movable mold side core33to prevent the deformation and/or damage of the sand core W provided that the front end faces23a,23aabut on a portion other than the face for molding the sand core W.

Thus, it is preferable that the fixed mold side core23and the movable mold side core33comprise a stopper member or a shape to keep constant a distance between the cores23and33so as to prevent nearing each other when the molds are opened

In the foregoing embodiment, the supporting face41aof the molded article receiving jig41is stepped so that it conforms to the surface contour of the lower face W1of the sand core W. Alternatively, the supporting face41amay be flat face on which an elastomer such as sponge is applied.

The sand core forming mold12is used as mold in the present embodiment. Metallic mold or resin mold which is used for applications other than molding of the sand core W may be used as a mold.

In addition to the technical concepts as set forth in Claims, technical concepts which are derived from the foregoing embodiments will be described as follows.

(1) In any one of Claims1through20, the parting face of the forming mold is perpendicular to the mold opening direction and the parting face of the forming mold on the side of the first mold is parallel with that of the forming mold on the side of second mold.

(2) In any one of Claims1through20and the technical concept (1), said first and second molds are fixed and movable, respectively.

(3) In any one of Claims1through20and the technical concepts (1) and (2), the molded article which is obtained using said forming mold is a sand core.

(4) In any one of Claims1through20and the technical concepts (1) through (3), the first and second movable insert members are used for forming a concave or convex on the molded article which is obtained using the forming mold.

(5) In any one of Claims1through20and the technical concepts (1) through (4), the separation distance between the front end faces of the first and second movable insert members is kept constant on the opening of the mold.

(6) In any one of Claims1through20and the technical concepts (1) through (5), at least one of the first and second movable insert members is extendable and retractable in parallel with the mold opening direction.

(7) A method of producing a molded article in which a molded article obtained by using first and second molds having first and second molding faces, respectively, is removed by conducting a mold opening for separating the first mold from the second mold, is characterized in that the method comprises providing a first movable insert member having a front end face forming a part of the first molding face so that the first movable insert member is extendable into or retractable from the first mold; providing a second movable insert member having a front end face forming a part of the second molding face so that the second movable insert member is extendable into or retractable from the second mold; and keeping the molded article to be held between both movable insert members by extending both of the movable insert members in a mold opening direction when the molds (mold assembly) are opened.