Patent Publication Number: US-2021187597-A1

Title: Core manufacturing apparatus

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2019-228940 filed on Dec. 19, 2019 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a core manufacturing apparatus. 
     2. Description of Related Art 
     There are known core manufacturing apparatuses that manufacture cores by kneading core sand along with a binder etc. in a kneading vessel and ejecting and packing the kneaded core sand (kneaded sand) into a mold. A core manufacturing apparatus developed by the present inventors kneads core sand with the kneading vessel in a horizontally lying state, as disclosed in Japanese Patent Application Publication No. 2017-131913 (JP 2017-131913 A). Since this core manufacturing apparatus ejects kneaded sand in a horizontal direction while the kneading vessel is in the horizontally lying state, it is difficult to pack the kneaded sand to the far corners of a mold. 
     Therefore, the present inventors developed another core manufacturing apparatus that kneads core sand with the kneading vessel in a horizontally lying state and then brings the kneading vessel into a vertically standing state to eject the kneaded sand downward and pack it into a mold, as disclosed in Japanese Patent Application Publication No. 2019-202323 (JP 2019-202323 A). 
     SUMMARY 
     In the core manufacturing apparatuses disclosed in JP 2017-131913 A and JP 2019-202323 A, a feed port through which core sand is fed is provided on the upper side of the kneading vessel in the horizontally lying state. Although this is not clearly shown in JP 2017-131913 A and JP 2019-202323 A, a storage unit (e.g., a hopper) that stores a predetermined amount of core sand to be fed into the kneading vessel is provided above the kneading vessel and coupled to the feed port. 
     The core manufacturing apparatus disclosed in JP 2019-202323 A requires keeping the storage unit in the same posture, regardless of the posture of the kneading vessel, while the kneading vessel turns from the horizontally lying state to the vertically standing state. To achieve this, one can simplistically conceive a configuration in which the storage unit is temporarily uncoupled from the kneading vessel before the kneading vessel transitions from the horizontally lying state to the vertically standing state, and the storage unit and the kneading vessel are coupled together again after the kneading vessel returns to the horizontally lying state. However, this configuration has the disadvantage of poor core productivity due to the time taken for uncoupling and coupling actions. 
     The present disclosure provides a core manufacturing apparatus that achieves excellent productivity. 
     A core manufacturing apparatus as one aspect of the present disclosure includes: a storage unit configured to store core sand; a kneading vessel, which is tubular, configured to be fed with the core sand though a feed port to which the storage unit is coupled; a kneading rod provided inside the kneading vessel so as to extend in a longitudinal direction of the kneading vessel, and configured to knead the core sand by rotating around an axis parallel to the longitudinal direction; and a piston configured to eject the kneaded core sand from one end, in the longitudinal direction, of the kneading vessel. The kneading vessel is configured to be able to transition between a horizontally lying state and a vertically standing state by turning around a first shaft. The kneading vessel is configured to be fed with the core sand in the horizontally lying state through the feed port that is located on the upper side of the kneading vessel. The piston is configured to eject the core sand downward and pack the core sand into a mold with the kneading vessel in the vertically standing state. The storage unit is coupled to the kneading vessel so as to be turnable around a second shaft parallel to the first shaft, and is configured to remain coupled to the kneading vessel in the same posture while the kneading vessel turns. 
     The core manufacturing apparatus of this aspect does not require uncoupling the storage unit from the kneading vessel when the kneading vessel turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity. 
     In the above aspect, the core manufacturing apparatus may include a parallel linkage having a driver that has the first shaft and the second shaft as joints. The core manufacturing apparatus thus configured is excellent in maintainability. 
     In the above aspect, the storage unit may include a hopper configured to store the core sand to be fed into the kneading vessel, and a weigher configured to measure the weight of the hopper. The weigher may be configured to measure the weight of the core sand stored in the hopper while the core sand is supplied to the hopper. The core manufacturing apparatus thus configured is capable of simultaneously weighing and storing core sand and thereby achieves excellent productivity. 
     In the above aspect, the storage unit may further include a preliminary tank configured to store the core sand to be supplied to the hopper, and a valve provided on a pipe connecting the preliminary tank and the hopper to each other. When the core sand is supplied from the preliminary tank to the hopper, the degree of opening of the valve may be adjusted based on the weight of the hopper measured by the weigher. The core manufacturing apparatus thus configured can accurately control the weight of core sand to be fed into the weigh hopper. 
     In the above aspect, the parallel linkage may include a first link fixed on the kneading vessel. The kneading vessel may further include a turning support member that supports the kneading vessel. The storage unit may further include a support member that supports the storage unit. The kneading vessel may be configured to be supported through the first link so as to be turnable around the first shaft. The support member may be coupled to the first link so as to be turnable around the second shaft. 
     In the above aspect, the parallel linkage may include a second link that is coupled to the turning support member so as to be turnable around a third shaft and coupled to the support member so as to be turnable around a fourth shaft. 
     In the above aspect, the parallel linkage may include the turning support member, the support member, the first link, and the second link as components. The parallel linkage may have the first shaft, the second shaft, the third shaft, and the fourth shaft as joints. 
     Having these aspects, the present disclosure can provide a core manufacturing apparatus that achieves excellent productivity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is side views showing actions of a core manufacturing apparatus according to an embodiment; 
         FIG. 2  is a sectional view of the core manufacturing apparatus according to the embodiment; 
         FIG. 3  is a sectional view of the core manufacturing apparatus according to the embodiment; 
         FIG. 4  is a sectional view of the core manufacturing apparatus according to the embodiment; and 
         FIG. 5  is a detailed sectional view of a weigh hopper  22 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     A specific embodiment to which the present disclosure is applied will be described in detail below with reference to the drawings. It is not intended that the present disclosure is limited to the following embodiment. To clarify the illustration, the following description and drawings are simplified as necessary. 
     Overall Configuration and Actions of Core Manufacturing Apparatus 
     First, the overall configuration and actions of a core manufacturing apparatus according to the embodiment will be described with reference to  FIG. 1 .  FIG. 1  is side views showing the actions of the core manufacturing apparatus according to the embodiment. It should be understood that the right-handed xyz-orthogonal coordinate system shown in  FIG. 1  and the other drawings is for the convenience of illustrating the positional relationship among components. Normally, a z-axis positive direction is a vertically upward direction and an xy-plane is a horizontal plane, which applies to all the drawings. 
     As shown in  FIG. 1 , the core manufacturing apparatus according to the embodiment includes a kneading unit  10 , a storage unit  20 , and links L 1 , L 2 . A brief overview of each component will be given here with reference to  FIG. 1 , and details thereof will be given later. The kneading unit  10  includes a kneading vessel  11  that is fed with core sand and kneads the core sand, a turning support member  13  that supports the kneading vessel  11 , and a piston  14  that ejects the kneaded core sand. The storage unit  20  includes a preliminary tank  21  that temporarily stores core sand, a weigh hopper  22  that stores, while weighing, a predetermined amount of core sand to be fed into the kneading vessel  11 , and a support member  23  that supports the preliminary tank  21  and the weigh hopper  22 . 
     Here, the kneading vessel  11  is supported so as to be turnable around a shaft (first shaft) A 1  by the turning support member  13  through the link L 1  fixed on the kneading vessel  11 . As shown in  FIG. 1 , the kneading vessel  11  is capable of transitioning between a horizontally lying state and a vertically standing state by turning 90° around the shaft A 1 . In the horizontally lying state shown on the left side in  FIG. 1 , core sand is fed from the weigh hopper  22  into the kneading vessel  11  and the fed core sand is kneaded. Then, in the vertically standing state shown on the right side in  FIG. 1 , the core sand is ejected downward (in a z-axis negative direction) and packed into a mold by the piston  14 . Shown at the center in  FIG. 1  is a state where the kneading vessel  11  is in transition from the horizontally lying state to the vertically standing state or from the vertically standing state to the horizontally lying state. 
     As will be described in detail later, the posture of the storage unit  20  depends on the support member  23 . As shown in  FIG. 1 , the support member  23  is coupled to the link L 1  so as to be turnable around a shaft (second shaft) A 2 . Since the link L 1  is fixed on the kneading vessel  11 , the support member  23  (i.e., the storage unit  20 ) is coupled to the kneading vessel  11  so as to be turnable around the shaft A 2 . The link L 2  is coupled to the turning support member  13  so as to be turnable around a shaft A 3  and coupled to the support member  23  so as to be turnable around a shaft A 4 . 
     Here, the turning support member  13 , the support member  23 , and the links L 1 , L 2  constitute a parallel linkage having the four shafts A 1  to A 4  as joints. In the example of  FIG. 1 , the turning support member  13  is fixed on the ground and corresponds to a fixed link in the parallel linkage. The link L 1  fixed on the kneading vessel  11  corresponds to a driver. The link L 2  and the support member  23  correspond to a follower and a connector, respectively. 
     Thus configured, the core manufacturing apparatus according to the embodiment keeps the storage unit  20  coupled to the kneading vessel  11  in the same posture while the kneading vessel  11  turns. It is not necessary to uncouple the storage unit  20  from the kneading vessel  11  when the kneading vessel  11  turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity. 
     As long as the requirement that the link L 1  fixed on the kneading vessel  11  should constitute a driver is met, the support member  23  may constitute a fixed link and the turning support member  13  may constitute a connector. The storage unit  20  is required to be coupled to the kneading vessel  11  so as to be turnable around the shaft A 2  parallel to the turning shaft A 1  of the kneading vessel  11 , and to remain coupled to the kneading vessel  11  in the same posture while the kneading vessel  11  turns. As long as this requirement is met, the storage unit  20  may be kept in the same posture by connecting the shafts A 1 , A 2  to each other by a belt or a gear instead of the parallel linkage. However, compared with the means using a belt or a gear, a parallel linkage is less likely to fail when core sand sticks thereto and is excellent in maintainability. 
     Detailed Configuration of Core Manufacturing Apparatus 
     Next, each component of the core manufacturing apparatus according to the embodiment will be described in detail with reference to  FIG. 1  to  FIG. 4 .  FIG. 2  to  FIG. 4  are sectional views of the core manufacturing apparatus according to the embodiment.  FIG. 2  and  FIG. 3  are sectional views showing states where the kneading vessel  11  is in the horizontally lying state shown on the left side in  FIG. 1 .  FIG. 4  is a sectional view showing a state where the kneading vessel  11  is in the vertically standing state shown on the right side in  FIG. 1 . As shown in  FIG. 2  to  FIG. 4 , the core manufacturing apparatus according to the embodiment includes the kneading unit  10 , the storage unit  20 , the links L 1 , L 2 , and a control unit  30 . 
     Configuration of Kneading Unit  10   
     The configuration of the kneading unit  10  will be described. As shown in  FIG. 2  to  FIG. 4 , the kneading unit  10  includes the kneading vessel  11 , kneading rods  12 , the turning support member  13 , and the piston  14 . The kneading vessel  11  is a tubular member that is fed with core sand S 1  through a feed port  11   a  to which the storage unit  20  is coupled. The kneading vessel  11  has, for example, a cylindrical shape. As shown in  FIG. 2  and  FIG. 3 , the feed port  11   a  is provided on an upper side of the kneading vessel  11  in the horizontally lying state of the kneading vessel  11 . Thus, the core sand S 1  can be fed into the kneading vessel  11  by gravity. 
     An ejection port  11   b  through which the kneaded sand S 1  is ejected is provided in one end surface, in a longitudinal direction, of the kneading vessel  11 , and the piston  14  is provided on the other end surface. In the shown example, the ejection port  11   b  is provided so as to protrude from the end surface of the kneading vessel  11 . When ejecting the core sand S 1 , a core forming mold (not shown) is coupled to the ejection port  11   b.    
     The core sand S 1  fed into the kneading vessel  11  is kneaded along with a binder. The core sand S 1  may be either natural sand or artificial sand. The binder is, for example, an inorganic binder containing liquid glass and water, but may instead be an organic binder. The binder is sprayed from a spraying device (not shown) provided on an inner circumferential surface of the kneading vessel  11 . The spraying device is provided, for example, in the vicinity of the feed port  11   a.    
     The kneading rods  12  are provided inside the kneading vessel  11  so as to extend along substantially the entire length of the kneading vessel  11  in the longitudinal direction. There is a plurality of kneading rods  12 , and these kneading rods  12  are fixed on, for example, a disc-shaped rotating base  12   a . The rotating base  12   a  is provided inside the kneading vessel  11 , at an end on the side of the piston  14 , and rotates around an axis parallel to the longitudinal direction of the kneading vessel  11 . Thus, the core sand S 1  fed into the kneading vessel  11  is kneaded by the kneading rods  12 . 
     The kneading rods  12  are disposed, for example, in a radial arrangement centered on a rotational axis. Alternatively, the kneading rods  12  may be disposed in an S-shape so as to be point-symmetrical with the rotational axis as the center. The shape of the kneading rods  12  is not particularly limited as long as it is a columnar shape extending parallel to the rotational axis. The cross-sectional shape of the kneading rods  12  is, for example, a circular shape, but may instead be an elliptical shape, a polygonal shape, etc. 
     Although this is not shown, the rotating base  12   a  is an external gear and driven to rotate by a driving source, such as a motor, through a gear disposed at a circumferential edge of the rotating base  12   a . The operation of this driving source is controlled by, for example, the control unit  30 . The rotational axis of the rotating base  12   a  coincides with a central axis of the cylindrical kneading vessel  11  in this embodiment, but the present disclosure is not particularly limited to this arrangement. 
     As described above and shown in  FIG. 1 , the kneading vessel  11  is supported so as to be turnable around the shaft (first shaft) A 1  by the turning support member  13  through the link L 1  fixed on the kneading vessel  11 . As shown in  FIG. 1 , the kneading vessel  11  is capable of transitioning between the horizontally lying state and the vertically standing state by turning 90° around the shaft A 1 . The kneading vessel  11  is driven to rotate by a driving source (not shown), such as a motor, coupled to the shaft A 1 . The operation of this driving source is controlled by, for example, the control unit  30 . 
     As shown in  FIG. 2  and  FIG. 3 , with the kneading vessel  11  in the horizontally lying state, the core sand S 1  is fed into the kneading vessel  11  through the feed port  11   a  located on the upper side of the kneading vessel  11 , and the fed core sand S 1  is kneaded by the kneading rods  12 . When a valve V 2  and a valve V 3  to be described later are opened, the core sand S 1  stored in the weigh hopper  22  is fed into the kneading vessel  11  by gravity.  FIG. 2  shows a state where the valve V 3  is closed, and  FIG. 3  shows a state where the valve V 3  is opened. To keep moisture out of the kneading vessel  11 , the valves V 2 , V 3  are closed except when the core sand S 1  is fed. 
     As shown in  FIG. 4 , with the kneading vessel  11  in the vertically standing state, the core sand S 1  is ejected downward (in the z-axis negative direction) and packed into a mold  40  by the piston  14 . In the shown example, the mold  40  is composed of an upper mold  41  and a lower mold  42 , with a cavity  43  formed therebetween. The core sand S 1  ejected from the kneading vessel  11  by the piston  14  is packed into the cavity  43  to manufacture a core. This core is used, for example, to cast an on-board engine part. 
     The piston  14  shown in the drawings is an electrically operated ball-screw piston, and includes a piston head  141 , a piston rod  142 , and a motor  143 . The piston head  141  is housed inside the kneading vessel  11  and disposed closer to the ejection port  11   b  than the rotating base  12   a  is. The piston head  141  is driven by the motor  143  that is coupled to the piston head  141  through the piston rod  142  that extends through the end surface of the kneading vessel  11 . The operation of the motor  143  is controlled by, for example, the control unit  30 . 
     Except during ejection, the piston head  141  is on standby at an end of the kneading vessel  11  on the side of the piston  14 . During ejection, the piston head  141  advances in the longitudinal direction of the kneading vessel  11  and ejects the kneaded core sand S 1  through the ejection port  11   b . As described above and shown in  FIG. 4 , the core sand S 1  is ejected with the kneading vessel  11  in the vertically standing state.  FIG. 4  shows a state where the piston head  141  has descended and the core sand S 1  has been ejected. 
     A plug  11   c  made of rubber, for example, is mounted at a root of the ejection port  11   b , i.e., on an inner end surface of the kneading vessel  11 . The plug  11   c  can keep the core sand S 1  fed into the kneading vessel  11  from leaking out of the kneading vessel  11 . On the other hand, the plug  11   c  has an incision that has, for example, a cross shape as seen in a plan view and extends through a central portion of the plug  11   c  in a thickness direction thereof. Therefore, the plug  11   c  opens due to the incision when the core sand S 1  inside the kneading vessel  11  is pressurized and ejected. 
     The gap between the inner circumferential surface of the kneading vessel  11  and an outer circumferential surface of the piston head  141  is kept sealed by a seal member or the like. The piston head  141  has through-holes into which the kneading rods  12  are fitted and inserted. The gap between an inner circumferential surface of each of these through-holes and an outer circumferential surface of the kneading rod  12  is also kept sealed by a seal member or the like. This configuration allows the core sand S 1  inside the kneading vessel  11  to be ejected through the injection port  11   b  without leaking. The piston head  141  can rotate along with the kneading rods  12 . While the piston  14  is an electrically operated piston here, the piston  14  is not limited thereto and may instead be a piston driven by air pressure, oil pressure, or the like. 
     Configuration of Storage Unit  20   
     Next, the configuration of the storage unit  20  will be described. As shown in  FIG. 2  to  FIG. 4 , the storage unit  20  includes the preliminary tank  21 , the weigh hopper  22 , the support member  23 , pipes P 1  to P 3 , and valves V 1  to V 3 . 
     The preliminary tank  21  is a tank that temporarily stores the core sand S 1  to be supplied to the weigh hopper  22 . In the shown example, an upper part of the preliminary tank  21  has a cylindrical shape and a lower part thereof has an inverted conical shape. Although this is not shown, the core sand S 1  is supplied to the preliminary tank  21  from a larger storage tank through a pipe etc. The preliminary tank  21  and the weigh hopper  22  are connected to each other by the pipe P 1 . 
     The weigh hopper  22  is provided under the preliminary tank  21 , and a lower portion of the preliminary tank  21  and an upper portion of the weigh hopper  22  are connected to each other by the pipe P 1 . The pipe P 1  is provided with the valve V 1 . When the valve V 1  is opened, the core sand S 1  stored in the preliminary tank  21  is fed into the weigh hopper  22  by gravity. The amount of core sand S 1  to be fed can be finely adjusted by adjusting the degree of opening of the valve V 1 . As will be described later in detail, the degree of opening of the valve V 1  is controlled by, for example, the control unit  30 . 
     The weigh hopper  22  stores a predetermined amount of core sand S 1  that has been weighed to be fed into the kneading vessel  11 . Here,  FIG. 5  is a detailed sectional view of the weigh hopper  22 . As shown in  FIG. 5 , the storage unit  20  includes a weigher  24  that measures the weight of the weigh hopper  22 , and a weigher support member  25  that supports the weigher  24 . The core sand S 1  stored in the weigh hopper  22  is weighed while the core sand S 1  is supplied to the weigh hopper  22 . Thus, the core manufacturing apparatus simultaneously weighs and stores core sand and thereby achieves excellent productivity. 
     The weigh hopper  22  includes a main body  221  and a lid  222 . The main body  221  has an inverted conical shape, and includes a flange  221   a  that is provided on an outer circumferential surface at an upper portion of the main body  221  and protrudes outward. The lid  222  is a disc-shaped cover lid and fits on an upper end portion of the main body  221 . A through-hole is provided at a central portion of the lid  222 , and the pipe P 1  is slidably fitted in the through-hole. 
     The pipe P 2  extends from a lower end of the main body  221 . A lower end portion of the pipe P 2  is slidably fitted in the pipe P 3 . The pipe P 2  is provided with the valve V 2 . When the valve V 2  and the valve V 3  to be described later are opened, the core sand S 1  stored in the weigh hopper  22  is fed into the kneading vessel  11  by gravity. As described above,  FIG. 3  shows the state where the valve V 3  is opened. Opening and closing of the valve V 2  and the valve V 3  are controlled by, for example, the control unit  30 . 
     The weigher  24  is, for example, a load cell and measures the weight of the weigh hopper  22 . The flange  221   a  of the weigh hopper  22  is placed on the weigher  24 . Specifically, the weigher  24  is loaded with the weights of the weigh hopper  22  (the main body  221  and the lid  222 ), the core sand S 1  inside the weigh hopper  22 , the pipe P 2 , and the valve V 2 . 
     Since the pipe P 1  is slidably fitted in the through-hole of the lid  222  as described above, the weigher  24  is not loaded with the weights of members located above the pipe P 1 . Since the pipe P 2  is slidably fitted in the pipe P 3 , the weigher  24  is not loaded with the weights of members located under the pipe P 3 . 
     The weight of the core sand S 1  fed from the preliminary tank  21  into the weigh hopper  22  can be learned from the weight measured by the weigher  24 . For example, based on the weight measured by the weigher  24 , the control unit  30  controls the degree of opening of the valve V 1  such that the weight of the core sand S 1  inside the weigh hopper  22  meets a target value. For example, the control unit  30  decreases the degree of opening of the valve V 1  as the weight of the core sand S 1  approaches the target value. Under this control, the weight of the core sand S 1  to be fed into the weigh hopper  22  can be accurately controlled. 
     As shown in  FIG. 5 , the weigher support member  25  includes a flat-plate-shaped platform  25   a  and pillars  25   b  that support the platform  25   a . The weigher  24  is placed and fixed on the platform  25   a . The pillars  25   b  are fixed on the support member  23 . Therefore, the weigher  24  is supported by the support member  23  through the weigher support member  25 . 
     A through-hole  25   c  through which the main body  221  of the weigh hopper  22  is inserted is provided at a central portion of the platform  25   a . Thus, the weigher support member  25  supports only the weigher  24  and does not directly support the weigh hopper  22 . This configuration allows the weigher  24  to measure the weight of the weigh hopper  22 . 
     On the other hand, the weigher  24  supports the weigh hopper  22  while measuring the weight of the weigh hopper  22 . Therefore, the weigher support member  25  supports the weigh hopper  22  through the weigher  24 . The support member  23  supports the weigh hopper  22  through the weigher support member  25  and the weigher  24 . 
     Thus, the support member  23  indirectly supports the weigh hopper  22 . Similarly, the support member  23  indirectly supports the preliminary tank  21  through a support member (not shown). This is why the posture of the storage unit  20  depends on the support member  23 . 
     Here, as shown in  FIG. 1 , the support member  23  is coupled to the link L 1  so as to be turnable around the shaft (second shaft) A 2 . Since the link L 1  is fixed on the kneading vessel  11 , the support member  23  is coupled to the kneading vessel  11  so as to be turnable around the shaft A 2 . The support member  23  is coupled to the link L 2  so as to be turnable around the shaft A 4 . The link L 2  is coupled to the turning support member  13  so as to be turnable around the shaft A 3 . 
     As described above and shown in  FIG. 1 , the turning support member  13 , the support member  23 , and the links L 1 , L 2  constitute a parallel linkage having the four shafts A 1  to A 4  as joints. In the example of  FIG. 1 , the turning support member  13  is fixed on the ground and corresponds to a fixed link in the parallel linkage. The link L 1  fixed on the kneading vessel  11  corresponds to a driver. The link L 2  and the support member  23  correspond to a follower and a connector, respectively. 
     Thus configured, the core manufacturing apparatus according to the embodiment keeps the storage unit  20  coupled to the kneading vessel  11  in the same posture while the kneading vessel  11  turns. It is not necessary to uncouple the storage unit  20  from the kneading vessel  11  when the kneading vessel  11  turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity. 
     Referring back to  FIG. 2  to  FIG. 4 , the description continues. The pipe P 3  is fixed on the support member  23 . The pipe P 2  is fitted at one end of the pipe P 3  as described above, and the valve V 3  is disposed at the other end of the pipe P 3 . The shape of the other end of the pipe P 3  is adapted to the surface shape of the valve V 3  so as to keep the core sand S 1  from leaking. 
     The valve V 3  is supported by the support member  23  shown in  FIG. 1  so as to be turnable around the turning shaft A 2  of the support member  23 . Thus, the valve V 3  can turn around the shaft A 2  along with the support member  23  relatively to the kneading vessel  11 , and can also turn around the shaft A 2  relatively to the support member  23 . Therefore, as shown in  FIG. 2  and  FIG. 4 , the support member  23  (i.e., the storage unit  20 ) can keep the same posture, with the valve V 3  in contact with the feed port  11   a , while the kneading vessel  11  turns. In other words, the feed port  11   a  can be sealed by the same valve V 3  not only when the kneading vessel  11  is in the horizontally lying state but also when it is in the vertically standing state. The turning actions (i.e., opening and closing) of the valve V 3  relatively to the support member  23  are controlled by, for example, the control unit  30 . 
     The valve V 3  has a shape obtained by cutting off a portion of a sphere along a plane in the example shown in  FIG. 2  to  FIG. 4 , but may instead have a shape of a perfect sphere. The valve V 3  opens and closes the feed port  11   a  by turning around the shaft A 2  while remaining in contact with the feed port  11   a  of the kneading vessel  11 . Since the valve V 3  has a spherical shape, the feed port  11   a  has a substantially circular shape. For example, the valve V 3  is made of resin and a resin seal member is provided at a circumferential edge of the feed port  11   a . The gap between the valve V 3  and the feed port  11   a  is kept sealed by this configuration. 
     A through-hole V 3   a  perpendicular to the turning shaft A 2  of the valve V 3  is formed inside the valve V 3 . In the state shown in  FIG. 2 , the valve V 3  is closed and the feed port  11   a  of the kneading vessel  11  is closed with the valve V 3 . On the other hand, in the state shown in  FIG. 3 , the valve V 3  has opened by turning around the shaft A 2  from the state shown in  FIG. 2 . In this state, the pipe P 3  and the feed port  11   a  of the kneading vessel  11  are connected to each other through the through-hole V 3   a  inside the valve V 3 , so that the core sand S 1  can be fed into the kneading vessel  11 . 
     The control unit  30  controls all actions in the core manufacturing apparatus, including the turning actions of the kneading vessel  11 , the rotating actions of the kneading rods  12 , the actions of the piston  14 , the opening and closing actions of the valves V 1  to V 3 , and adjustment of the degrees of opening of the valves. The control unit  30  may be divided into a plurality of units and provided as such. Although this is not shown, the control unit  30  functions as a computer and includes, for example, a computing part, such as a central processing unit (CPU), and a storing part, such as a random-access memory (RAM) or a read-only memory (ROM), that stores various control programs, data, etc. 
     As has been described above, in the core manufacturing apparatus according to the embodiment, the storage unit  20  is coupled to the kneading vessel  11  so as to be turnable around the shaft A 2 , and the storage unit  20  remains coupled to the kneading vessel  11  in the same posture while the kneading vessel  11  turns. It is not necessary to uncouple the storage unit  20  from the kneading vessel  11  when the kneading vessel  11  turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity. 
     The present disclosure is not limited to the above embodiment but can be changed as necessary within the scope of the gist of the disclosure.