JP3459913B2 - Method and apparatus for filling molding sand in frameless molding apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pair of molding flasks on both sides of a match plate provided with a model, and blows molding sand in a blow tank together with compressed air into the molding flask. TECHNICAL FIELD The present invention relates to a molding sand filling method and apparatus for a frameless molding apparatus for filling molding sand with a molding sand.

[0002]

2. Description of the Related Art Conventionally, as a general method for filling molding sand in a frameless molding apparatus, a match plate is arranged horizontally, and an upper molding frame and a lower molding frame are applied to both sides thereof from above and below, respectively. The press heads are fitted to the upper and lower end portions of the upper and lower flasks, respectively, and a pair of blow ports opened at each tip of the branch passage provided in the blow head is connected to each of the flasks. It is joined to a nozzle port penetrating one side wall, and the molding sand is simultaneously supplied from a lateral side to a pair of molding frames by compressed air to fill the molding sand. Alternatively, the match plates are arranged vertically, and a pair of molding frames on both side surfaces thereof are abutted from the left and right, and the pressure heads are respectively fitted to the ends of the respective molding frames opposite to the ends that abut on the match plate. Then, a pair of injection ports opened at each tip of the branch passage provided in the blow head are joined to a nozzle port penetrating the upper side wall of each casting frame to move the molding sand upward to the pair of casting frames by compressed air. It is supplied and filled from the same time.

[0003]

However, in the above-mentioned conventional method, when the match plate is arranged horizontally, the molding sand drops on the upper surface side due to gravity toward the model surface provided on the match plate. Although the rate is comparatively good, for the model on the lower surface side of the match plate, the molding sand must be filled against the gravity, especially for models with large undulations or deep concave models. There was a problem that made it worse. When the match plates are placed vertically, the left and right model surfaces are at right angles to the direction in which the molding sand is blown out, so the same as the bottom surface side when the match plates are placed horizontally under the left and right models. Problems are likely to occur. Further, in both of the above methods, unbalance of the shape of the branch passage provided in the blow head, adhesion of sand in the branch passage, sand is not evenly blown due to sand properties, etc. Filling of foundry sand tended to be poor. Further, in a model having large undulations or a model having a deep recess, the compressed air when the molding sand is blown serves as a cushion, and the depth of the recess is not filled with the molding sand, which is also a major factor that deteriorates the filling rate. A vent hole for releasing compressed air may be provided in the back of the recess to release the compressed air when blowing, but since the blowing is also performed on the companion flask at the same time, there is no way for the compressed air to escape. Almost no effect.

The present invention has been made in order to solve the above-mentioned problems, and one of a pair of flasks abutted on both sides of a match plate is filled with molding sand, and then the other is filled. It is to fill both molding flasks with molding sand at a high filling rate.

[0005]

In order to solve the above-mentioned problems, the structural feature of the present invention as set forth in claim 1 is that a pair of casting frames are brought into contact with both surfaces of a match plate, and Pressurizing heads are respectively fitted to the ends opposite to the ends abutting the match plate, and a pair of blowing ports opening at each tip of a branch passage formed in the blow head is provided in each of the pair of flasks. In the method of joining to the nozzle openings penetrating the side wall, respectively, and filling the molding flask from each of the blow openings of the blow head with compressed air into the molding flask through the nozzle openings, the branch of the blow head The branch passage is opened and closed by an opening / closing means provided in one or each of the passages to fill one of the pair of molding flasks with the molding sand and then to fill the other with the molding sand.

According to a second aspect of the present invention, there is provided a feature of the molding sand filling method of the frameless molding apparatus according to the first aspect, wherein a condition for filling the molding sand in the pair of flasks is satisfied. That is, after filling the molding sand on the surface side of the match plate provided with the bad model with the molding sand, the other molding sand is filled with the molding sand.

According to a third aspect of the present invention, there is provided a feature of the molding sand filling method of the frameless molding apparatus according to the first aspect, in which the pair of flasks are brought into contact with upper and lower surfaces of a match plate, respectively. That is, the casting flask and the lower casting flask are used, and after filling the lower casting flask with the molding sand, the upper casting flask is filled with the molding sand.

According to a fourth aspect of the present invention, there are provided a pair of casting frames, which are in contact with both sides of the match plate, respectively, and end portions of the respective casting frames, which are opposite to the end portions in contact with the match plate. A pair of pressure heads to be fitted in, a drive device for moving each pressure head forward and backward toward each of the flasks, and a pair of releasably joined nozzle openings penetrating the side walls of the pair of flasks. In a molding sand filling device of a frameless molding apparatus, which comprises a branch head having a branch passage whose opening is opened and supplies the molding sand to each of the flasks by compressed air, the branch passage of the blow head. That is, one or each of them is provided with the opening / closing means.

[0009]

In the invention according to claim 1 configured as described above, a pair of casting frames are respectively brought into contact with both surfaces of the match plate, and end portions of each casting frame which are brought into contact with the match plate are provided. Pressurizing heads are respectively fitted to the opposite end portions, and a pair of blow-in openings opening at each tip of a branch passage formed in the blow head is connected to a nozzle opening penetrating each side wall of the pair of flasks. Since they are connected to each other, the branch passage is opened and closed by the opening / closing means provided in one or each of the branch passages, and after filling the molding sand into one of the pair of flasks, the other is filled with the molding sand. There is no possibility that the molding sand will not be evenly blown into the pair of flasks at the same time due to unbalance of the branch passages of the blow head, and the filling of the molding sand into one of the flasks will not deteriorate. Filling molding sand with a high filling rate It can be.

In the invention according to claim 2 configured as described above, in the pair of casting frames, the casting is formed in the casting frame on the surface side of the match plate provided with the model having poor conditions for filling the molding sand. Since the other mold was filled with foundry sand after it was filled with sand, it is not affected by the imbalance of the branch passage of the blow head, etc. It is possible to fill molding sand with a high filling rate into a molding frame on the side of a model with poor quality.

In the invention according to claim 3 configured as described above, after filling the lower molding frame which contacts the lower surface of the match plate with the molding sand, the upper molding frame which contacts the upper surface is filled with the molding sand. Therefore, the lower molding frame, which must be filled against the gravity, can be filled with the molding sand at a high filling rate without being affected by the imbalance of the branch passage of the blow head.

In the invention according to claim 4 configured as described above, a pair of casting frames are abutted on both sides of the match plate, respectively, and the ends of the casting frames on the opposite side to the ends abutting on the match plate. The pressurizing heads are respectively fitted into the nozzles, and the pair of blow-in openings that open into the branch passages formed in the blow head are joined to the nozzle openings that penetrate through the side walls of the pair of casting frames, respectively, and one or each of the branch passages is connected. Since the branch passage is opened / closed by the opening / closing means provided in, the casting sand is filled into one of the pair of casting frames, and then the other is filled with the casting sand, and both casting frames are filled with the casting sand at a high filling rate. Can be filled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a molding sand filling device for carrying out the molding sand filling method for a frameless molding apparatus according to the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 is a match plate of a frameless molding apparatus that is horizontally arranged, and models 11 and 12 are provided on the upper and lower surfaces, respectively. Upper and lower molding flasks 13 and 14 are in contact with both surfaces of the match plate 10, respectively. The upper flask 13 has a match plate 1
The upper pressure head 1 is provided at the upper end opposite to the lower end that abuts 0.
5, the lower pressurizing head 17 is inserted into the lower flask 14 at the lower end opposite to the upper end that abuts the match plate 10, and the upper and lower spaces are defined on both sides of the match plate 10. It is like this. Vertical pressure heads 15, 17
Are vertically moved by cylinder devices 19 and 20, respectively.

Rods 21 are screwed into the four corners of the upper surface of the upper casting frame 13 so as to project upward, and are loosely fitted into engagement holes 22 formed in the flange portion 16 of the upper pressurizing head 15. 21
The large diameter portion formed at the upper end of the upper contact surface of the flange portion 16 abuts on the upper end surface of the flange portion 16, so that the upper casting frame 13 is hung at a position where the lower surface of the upper pressurizing head 15 is slightly fitted into the upper casting frame 13 from the upper end surface. Be sent down. Cylinder devices 23 are vertically attached to the four corners of the flange portion 18 of the lower pressurizing head 17, and
4, the piston 24 of the cylinder device 23 is raised so that the upper surface of the lower pressurizing head 14 is lifted up to a position where it is slightly fitted into the lower molding frame 14 from the lower end surface. The match plate 10 is placed on the lower flask 14 and held in an engaged state by a spring force by an engagement device (not shown). It is supposed to leave. The match plate 10 descends together with the lower flask 14 as the lower pressurizing head 17 descends, abuts on the pedestal of the match plate loading / unloading device 25 on the way, and separates from the lower flask 14 when a force of a predetermined value or more acts. The match plate loading / unloading device 25 is moved on the pedestal and retracted to a position where the upper pressurizing head 17 is allowed to pass.

The inner peripheral surfaces of the upper and lower casting frames 13 and 14 are formed with a taper that slightly expands downward.
When 14 is superposed without interposing the match plate 10, a continuous tapered hole is formed on the inner peripheral surface. Side walls 26, 2 in the same direction of the upper and lower flasks 13, 14
7, upper and lower nozzle openings 28 and 29 are provided so as to penetrate near the upper and lower pressure heads 15 and 17, respectively. Vent holes 30 to 32 are formed in the side walls of the upper and lower molding flasks 13 and 14 and in the concave portion of the model 12 of the match plate 10 so as to release the compressed air carrying the molding sand. Reference numeral 33 is a blow head connected to a blow tank, and upper and lower branch passages 34 and 35 are formed at the tip end thereof, and upper and lower branch passages 34 and 35 are respectively positioned at the casting sand filling position shown in FIG. The upper and lower blow ports 36, 37 which are joined to the upper and lower nozzle ports 28, 29 of the casting flasks 13, 14 are opened. An open / close valve 38 is rotatably supported in the upper branch passage 34, and is rotated by a drive device 39 between a closed position where the upper branch passage 34 is closed and an open position where the upper branch passage 34 is opened.

Next, the operation of the molding sand filling device of the frameless molding apparatus according to the present invention will be described together with the molding sand filling method.
In the state shown in FIG. 1, the upper and lower molding flasks 13 and 14 contact the upper and lower surfaces of the match plate 10 and overlap each other, and the piston 24 of the cylinder device 23 supports the lower surface of the lower molding flask 14 at the forward end position and pressurizes. The head 17 is lifted by the cylinder device 20 to position the upper and lower flasks 13, 14 and the match plate 10 at the casting sand filling position, and the opening / closing valve 38 is rotated to the closed position by the drive device 39 to close the upper branch passage 34. is doing.
In this state, the foundry sand filling device is operated, and as shown in FIG. 2, the foundry sand stored in the blow tank is compressed by the blow head 33, the lower branch passage 35, the lower blowing port 37,
It is supplied and filled into the lower flask 14 through the lower nozzle port 29. The upper branch passage 34 is closed by an opening / closing valve 38,
Since the molding sand is not filled with the compressed air, the compressed air supplied to the lower flask 14 is passed through the vent hole 32 formed in the concave portion of the model 12 of the match plate 10 to the empty upper flask 13. It is possible to escape, and it is possible to fill the molding sand against the gravity with a high filling rate in the deep model 12 of the concave portion where the filling condition is bad. Lower flask 14 after a predetermined time has passed
When the filling of the molding sand with the molding sand is completed, the on-off valve 38 is operated by the drive device 3
It is rotated to the open position by 9 and the upper branch passage 34 is opened. As a result, as shown in FIG. 3, the molding sand is supplied by the compressed air into the upper flask 13 through the blow head 33, the upper branch passage 34, the upper blowing port 36, and the upper nozzle port 28 to be filled therein. .

When the filling of the molding sand into the upper and lower flasks 13 and 14 is completed, the cylinder device 20 is retracted so that the piston 23 can be retracted while the lower pressurizing head 17 is stopped. 23 is connected to a pressure reducing valve, and the upper pressurizing head 15 is lowered by the cylinder device 19 at a predetermined pressure to squeeze the foundry sand in the upper and lower flasks 13, 14.
The upper mold and the lower mold 40, 41 are molded. Next, the cylinder device 2
The lower pressurizing head 17 is lowered by 0 to move the upper and lower molds 13,
14, the match plate 10, and the upper and lower molds 40, 41 are lowered, and immediately after the descent is started, the large diameter portion of the rod 21 is attached to the flange 1.
The lower mold 13 and the upper mold 40 are stopped from coming into contact with the upper end surface of the mold 6, and the model 11 of the match plate 10 is released from the upper mold 40. The lower pressurizing head 17 is further lowered by the cylinder device 20, the match plate 10 is brought into contact with the pedestal of the match plate inserting / extracting device 25 and its lowering is restricted, the model 12 is released from the lower mold 41, and then the lower casting is performed. The lower end surface of the frame 14 is stopped at the mold matching position immediately before contacting the lowering restricting piece 42. The match plate 10 separated from the upper mold 40 and the lower mold 41 is moved to a retracted position on the pedestal by the match plate loading / unloading device 25.

The upper pressing head 15 is driven by the cylinder device 19.
Is lowered, the upper flask 13 is superposed on the lower flask 14 stopped at the mold matching position, and the upper mold 40 is matched with the lower mold 41 to form a mold. At this time, the cylinder device 20 is connected to the pressure reducing valve, and the pressure above the set value does not act on the mold, so that the mold is not broken during mold matching. After that, by lowering the upper pressure head 15, the vertical pressure head 1
The molds 5 and 17 are lowered while sandwiching the mold with the pressure of the set value, and the lower flask 14 is restricted from being lowered by the lowering restricting piece 42, so that the molds are separated from the upper and lower flasks 13 and 14. When the lower pressure head 17 descends to the mold unloading position,
The upper pressurizing head 15 is raised to the ascending end position by the cylinder device 19, and the frameless mold is unloaded from the lower pressurizing head 17 by the carrying device.

When the mold is unloaded, the match plate 10
Is moved on the pedestal by the match plate loading / unloading device 25 and is positioned in the ascending / descending path of the lower pressurizing head 17.
With the piston 24 of the cylinder device 23 raised and supporting the lower surface of the lower flask 14 at the raised end position, the lower pressurizing head 17 is raised by the cylinder device 20, and the match plate 10 is placed on the lower flask 14 midway. And is held on the lower flask by spring force by the engaging device. When the match plate 10 is engaged with the lower flask 14, the match plate input / output device 2
5, it is superposed on the lower flask 14 by the lower pressurizing head 17 and is raised, and stopped at the casting sand filling position. The upper flask 13 suspended from the upper pressurizing head 15 retracted to the ascending end position is slightly lifted and comes into contact with the upper surface of the match plate 10 positioned at the casting sand filling position to return to the state of FIG. To do.

Next, a second embodiment of the molding sand filling device of the frameless molding apparatus according to the present invention will be described with reference to FIGS. 4 to 6. The second embodiment is different from the first embodiment in that the upper and lower molding flasks 13 and 14 and the match plate 10 are moved in the horizontal direction, and that the opening / closing valves are provided in both passages of the branch passage. Is substantially the same as that of the first embodiment, and therefore components corresponding to the components of the first embodiment are denoted by reference numbers obtained by adding 100 to the reference numbers assigned to the components of the first embodiment. The description is omitted.

The left and right casting frames 113 and 114 are mounted on a horizontal guide (not shown) so as to be movable in the left and right directions. Rods 121 are screwed into the four corners of the left end face of the left casting frame 113 to project horizontally to the left, and the flange portion 11 of the left pressure head 115 is provided.
6 is loosely fitted in an engagement hole 122 formed in the hole 6. A compression spring 146 is interposed between the flange portion 116 and the left end surface of the left casting flask 113, and the left casting flask 113 has a large diameter portion formed at the left end of the rod 121 due to the repulsive force of the compression spring 146. The right end surface of the left pressurizing head 115 is slightly fitted into the left molding frame 113 until it comes into contact with the left end surface of the 116. Cylinder devices 123 are horizontally attached to the four corners of the flange portion 118 of the right pressurizing head 117, the right flask 114 is connected to the piston 124 of the cylinder device 123, and the right pressurizing head 117 is moved forward by the piston 124. The left end face of is moved to a position where it is slightly inserted into the right molding frame 114 from the right end face.

Left and right branch passages 134, 135 are formed at the lower end of the blow head 133, and the left and right branch passages 134, 1 are formed.
The left and right nozzle ports 12 of the left and right casting frames 113 and 114 positioned at the casting sand filling position shown in FIG.
Left and right blow-in ports 136 and 137, which are joined to 8, 129, are opened. On-off valves 138 and 148 are rotatably supported in the left and right branch passages 134 and 135, respectively.
9 and 149 respectively rotate the left and right branch passages 134 and 135 between a closed position and an open position.

Next, the operation of the second embodiment will be described together with the method for filling foundry sand. In the state shown in FIG. 4, the left and right casting frames 113 and 114 contact and overlap the left and right surfaces of the match plate 110, the piston 124 of the cylinder device 123 is located at the leftward end, and the pressure head 117 is moved by the cylinder device 120. Leftward and rightward to position the left and right flasks 113, 114 and the match plate 110 at the casting sand filling position, and open / close valve 13
Reference numerals 8 and 148 are rotated to the closed position by the drive devices 139 and 149 to close the left and right branch paths 134 and 135. In this state, the foundry sand filling device is operated, and as shown in FIG. 5, the right opening / closing valve 148 is rotated to the open position by the drive device 149, so that the foundry sand stored in the blow tank is blown by the blow head 133 and compressed air. It is supplied and filled into the right flask 114 through the right branch passage 135, the right blowing port 137, and the right nozzle port 129. The upper branch passage 134 is the opening / closing valve 13.
Since it is closed by 8 and the molding sand is not filled with compressed air, the compressed air supplied to the right molding flask 114 is emptied through the vent hole 132 formed in the concave portion of the model 112 of the match plate 110. A deep model 112 with a concave shape that can be released into the left flask 113 and is filled with molding sand under poor filling conditions.
Can be filled with a high filling rate. When the filling of the molding sand into the right flask 114 is completed after a lapse of a predetermined time, the opening / closing valve 138 is rotated to the open position by the drive device 139, and the left branch passage 134 is opened. As a result, as shown in FIG. 6, the foundry sand is compressed by the blow air 133, the left branch passage 134, the left blowing port 136, and the left nozzle port 128.
It is supplied to and filled in the left flask 113 through.

When the filling of the molding sand into the left and right flasks 113, 114 is completed, the cylinder device 120 is blocked so that the cylinder device 120 is prevented from moving backward and the right pressure head 117 is stopped. 123 is connected to a pressure reducing valve, and the left pressurizing head 115 is moved to the right by a cylinder device 119 at a predetermined pressure to squeeze the foundry sand in the left and right casting frames 113, 114 to mold the upper mold and the lower mold 140, 141. . Next, by the cylinder device 120, the right pressure head 11
7 is moved to the right to move the left and right casting frames 113 and 114, the match plate 110, and the upper and lower molds 140 and 141 to the right, and immediately after the start of the rightward movement, the large diameter portion of the rod 121 comes into contact with the left end surface of the flange portion 116 to the left. The rightward movement of the casting frame 113 and the upper die 140 is stopped, and the model 111 of the match plate 110 is moved to the upper die 14
It is released from 0. The right pressurizing head 117 is further moved to the right by the cylinder device 120, the match plate 110 is brought into contact with the pedestal of the match plate loading / unloading device 125 to restrict the rightward movement, and the model 112 is released from the lower mold 141. The right end surface of the right casting frame 114 is stopped at the mold matching position immediately before contacting the rightward travel restricting piece 142. Upper mold 140, lower mold 1
The match plate 110 released from 41 is moved to the retracted position on the cradle by the match plate loading / unloading device 125.

The left pressure head 1 is driven by the cylinder device 119.
15 is moved to the right and stopped at the mold matching position.
The left casting frame 113 is overlapped with the upper mold 140, and the upper mold 140 is matched with the lower mold 141 to form a mold. At this time, the cylinder device 120 is connected to the pressure reducing valve, and the pressure above the set value does not act on the mold, so that the mold is not broken during mold matching. By the rightward movement of the left pressure head 115 thereafter, the left and right pressure heads 115 and 117 are moved rightward while the mold is clamped at the pressure of the set value, and the right flask 114 is moved rightward by the rightward movement restricting piece 142. As the mold is regulated, the mold is left and right flask 1
Separated from 13,114. Left and right pressure head 115,
When 117 is located at the mold unloading position, the frameless mold is supported by the transfer device, and the left pressurizing head 115 is moved to the cylinder device 1.
The mold is opened to the left by 19 to open the mold, and the mold is carried out by the carrier device.

When the left pressure head 115 is moved to the left advance position, the match plate 110 is moved along the pedestal by the match plate loading / unloading device 125 and positioned in the moving path of the right pressure head 117. Cylinder device 1
The piston 124 of No. 23 is located at the left end and the right flask 114
Is moved to the left relative to the right pressure head head 117, the right pressure head 117 is moved to the left by the cylinder device 120, and the match plate 110 is moved to the right casting frame 1 in the middle thereof.
14 is overlaid on the right casting frame 11 by a spring force by an engaging device.
Held at 4. Match plate 110 is right casting frame 114
Is released from the match plate loading / unloading device 125, is superposed on the right molding flask 114 by the right pressure head 117 and is moved leftward, and is stopped at the casting sand filling position. The left casting frame 113 supported by the left pressurizing head 115 retracted to the leftward end position is moved slightly to the left against the repulsive force of the compression spring 146, and the left side of the match plate 110 positioned at the casting sand filling position. It comes into contact with the upper surface and returns to the state of FIG.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment of a molding sand filling device of a frameless molding apparatus according to the present invention.

FIG. 2 is a diagram showing a state where the lower molding flask in FIG. 1 is filled with molding sand.

FIG. 3 is a view showing a state where the upper and lower molding flasks in FIG. 1 are filled with molding sand.

FIG. 4 is a side sectional view showing a second embodiment of the present invention.

5 is a view showing a state where the right molding flask in FIG. 4 is filled with molding sand.

FIG. 6 is a view showing a state where the left and right flasks in FIG. 1 are filled with molding sand.

[Explanation of symbols]

10,110 ... Match plate, 11,12,11
1,112 ... Model, 13,14,113,114 ...
Vertical (horizontal) casting frame, 15, 17, 115, 117 ...
Vertical (left and right) pressure heads, 19, 20, 23, 119,
120, 123 ... Cylinder device 21,121 ...
.Rod 22,122 ... Engagement holes 25,125
..Match plate loading / unloading devices, 26, 27, 126, 1
27 ... Side wall, 28, 29, 128, 129 ... Vertical (left / right) nozzle opening, 33, 133 ... Blow head, 34, 35, 134, 135 ... Vertical (left / right) branch passage, 36 , 37, 136, 137 ... Vertical (left and right) blow ports, 38, 138, 148 ... Open / close valve, 3
9, 139, 149 ... Driving device, 40, 140 ...
-Upper mold, 41, 141 ... Lower mold.

Claims (4)

(57) [Claims] 1. A pair of casting frames are abutted on both sides of a match plate, and a pressurizing head is fitted to each end of each casting frame opposite to the end abutting the match plate, and the blow head is attached to the blow head. A pair of blowing ports that open at each tip of the formed branch passage are respectively joined to nozzle ports that penetrate through the side walls of the pair of casting frames, and the molding sand is compressed from each blowing port of the blow head by compressed air. According to the method of filling each of the flasks through each of the nozzle openings, by opening and closing the branch passage by the opening and closing means provided in one or each of the branch passages of the blow head, A method for filling molding sand in a frameless molding apparatus, which comprises filling molding sand into one side and then filling the other side with molding sand. 2. The molding sand filling method for a frameless molding apparatus according to claim 1, wherein a face of a match plate provided with a model having poor conditions for filling the molding sand in the pair of flasks. A method for filling a molding sand in a frameless molding apparatus, which comprises filling the molding sand on one side with the molding sand and then filling the other molding sand with the molding sand. 3. The molding sand filling method for a frameless molding apparatus according to claim 1, wherein the pair of molding frames are an upper molding frame and a lower molding frame that are in contact with upper and lower surfaces of a match plate, respectively. After filling the molding sand with the molding sand, the molding sand is filled into the upper flask, and the molding sand filling method for a frameless molding apparatus is characterized. 4. A pair of casting frames, which are in contact with both sides of the match plate, respectively, and a pair of pressure heads, which are fitted into the respective casting frames at the ends opposite to the ends in contact with the match plate, respectively. It has a drive device for moving the pressure head forward and backward toward each of the flasks, and a branch passage having a pair of blow-in openings detachably joined to the nozzle openings penetrating the side walls of the pair of flasks. In a molding sand filling device of a frameless molding apparatus having a blow head for supplying molding sand to each of the flasks by compressed air, one or each of the branch passages of the blow head is provided with an opening / closing means. A casting sand filling device for a frameless molding machine, which is characterized by: