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Timestamp: 2018-04-26 04:05:28
Document Index: 547999103

Matched Legal Cases: ['ARTS 1974', 'art 13', 'art 13', 'art 14', 'art 13', 'art 14']

Method of producing molded green body and producing insert by baking the green body - Kabushiki Kaisha Meidensha
United States Patent 7504063
Ogita, Kiyofumi (Shizuoka, JP)
Iida, Ken (Shizuoka, JP)
10/885081
B28B3/00; B28B21/18; C04B33/32; C04B35/117
264/667, 264/645
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6372165 Cold isopressing method 2002-04-16 Apte et al. 264/112
5900205 Method for blow molding a CVJ boot 1999-05-04 Sadr et al. 264/531
5269988 Electrolyte holder 1993-12-14 Coetzer 264/614
5137663 Process and container for encapsulation of workpieces for high pressure processing 1992-08-11 Conaway 264/36.15
4655984 Method of and apparatus for isostatically pressing a body from particulate material 1987-04-07 Hinton et al. 264/314
4409174 Method for batch production of isostatically pressed calcium powder discs 1983-10-11 Toy et al. 264/313
3824051 MOLD APPARATUS FOR ISOSTATIC PRESSING OF HOLLOW PARTS 1974-07-16 Van Leemput 425/78
3500513 ISODYNAMIC APPARATUS FOR MOLDING CERAMIC PIPE 1970-03-17 Stanley 425/193
JP0056326 February, 1993
JP11320525 November, 1999 MANUFACTURE OF CERAMIC INSERT ELEMENT FOR INSERT INSTRUMENT
JP11322406 November, 1999 PRODUCTION OF CERAMIC INSERT ELEMENT IN INSERT APPARATUS
JP11322447 November, 1999 PRODUCTION OF CERAMIC INSERT ELEMENT ASSEMBLY IN INSERT APPLIANCE
JP2001214535A 2001-08-10 INSERT APPARATUS
JPH056326Y2 1993-02-18
JPH11320525A 1999-11-24
JPH11322447A 1999-11-24
JPH11322406A 1999-11-24
1. A method of producing a molded green body of an insert which is used as an insert element embedded in a concrete structure and has recesses on its outer surface, the method comprising: (a) preparing a flexible mold which includes a flexible hollow member and upper and lower lids which can close upper and lower open ends of the flexible hollow member to form in the flexible hollow member a molding cavity, the flexible hollow member having projections that are exposed to the molding cavity; (b) setting a cylindrical core to the lower lid while making an assured positioning of the cylindrical core relative to the lower lid by intimately putting a flat surface of the cylindrical core on a flat surface of the lower lid, and setting the lower lid to the lower open end of the flexible hollow member in such a manner that a major portion of the core is projected into the molding cavity, the major portion of the core being formed on its cylindrical outer surface with a male thread portion and having a closed top end; (c) pouring a powdered ceramic material into the molding cavity from the upper open end of the flexible hollow member to fill the molding cavity with the powdered ceramic material, and setting the upper lid to the upper open end of the flexible hollow member in such a manner that a space defined between the upper lid and the closed top end of the cylindrical core is filled with the powdered ceramic material; wherein the flexible mold is nut in a flexible tube of a female die after the pouring step, and then the flexible tube is compressed by a hydrostatic pressure to compress the flexible hollow member in the flexible tube thereby to compress the powdered ceramic material in the molding cavity of the flexible mold; (d) compressing the flexible hollow member from the outside to compress the powdered ceramic material thereby to produce in the molding cavity a molded green body that holds therein the cylindrical core; (e) removing the molded green body together with the cylindrical core from the flexible mold once the molding of the molded green body is sufficiently carried out; and (f) turning the cylindrical core in a releasing direction relative to the molded green body thereby to remove the cylindrical core from the molded green body; wherein the cylindrical core is provided with an annular flange having the flat surface which is, upon completion of the step (b), intimately put on the flat surface of the lower lid, the annular flange having a periphery that is in contact with an inner wall of the flexible hollow member and having a diameter that is larger than that of an open side axial end of the molded green body, and wherein the lower lid and the cylindrical core are produced separately.
8. A method of producing an insert which is used as an insert element embedded in a concrete structure and has recesses on its outer surface, the method comprising: (a) preparing a flexible mold which includes a flexible hollow member and upper and lower lids which can close upper and lower open ends of the flexible hollow member to form in the flexible hollow member a molding cavity, the flexible hollow member having projections that are exposed to the molding cavity; (b) setting a cylindrical core to the lower lid while making an assured positioning of the cylindrical core relative to the lower lid by intimately putting a flat surface of the cylindrical core on a flat surface of the lower lid, and setting the lower lid to the lower open end of the flexible hollow member in such a manner that a major portion of the core is projected into the molding cavity, the major portion of the core being formed on its cylindrical outer surface with a male thread portion and having a closed top end; (c) pouring a powdered ceramic material into the molding cavity from the upper open end of the flexible hollow member to fill the molding cavity with the powdered ceramic material, and setting the upper lid to the upper open end of the flexible hollow member in such a manner that a space defined between the upper lid and the closed top end of the cylindrical core is filled with the powdered ceramic material; wherein the flexible mold is put in a flexible tube of a female die after the pouring step, and then the flexible tube is compressed by a hydrostatic pressure to compress the flexible hollow member in the flexible tube thereby to compress the powdered ceramic material in the molding cavity of the flexible mold; (d) compressing the flexible hollow member from the outside to compress the powdered ceramic material thereby to produce in the molding cavity a molded green body that holds therein the cylindrical core; (e) removing the molded green body together with the cylindrical core from the flexible mold once the molding of the molded green body is sufficiently carried out; (f) turning the cylindrical core in a releasing direction relative to the molded green body thereby to remove the cylindrical core from the molded green body; and (g) baking the molded green body to produce the insert; wherein the cylindrical core is provided with an annular flange having the flat surface which is, upon completion of the (b), intimately put on the flat surface of the lower lid, the annular flange having a periphery that is in contact with an inner wall of the flexible hollow member and having a diameter that is larger than that of an open side axial end of the molded green body, and wherein the lower lid and the cylindrical core are produced separately.
10. A method as claimed in claim 9, in which, for achieving the step (d), the combined flexible molds are put on a base member to constitute a male die, then the male die is inserted into a flexible tube of a female die and then the flexible tube is compressed by a hydrostatic pressure to compress the flexible hollow members of the combined flexible molds thereby to compress the powdered ceramic material in the combined flexible molds at the same time.
The female die “A” comprises a metal tube 1 that is a so-called pressure vessel and has a pressure inlet opening 1a formed through a cylindrical wall thereof.
A circular upper lid 2 of metal is detachably put on an upper open end of the metal tube 1 to close the upper opening. The circular upper lid 2 comprises a circular base (no numeral), a larger-diameter circular projection 2a coaxially provided on a lower part of the circular base, and a smaller-diameter circular projection 2b coaxially provided on a lower part of the larger-diameter circular projection 2a. As shown, the larger-diameter circular projection 2a has a diameter just matched with the upper opening of the metal tube 1.
As shown, a circular lower metal lid 3 is incorporated with a lower end of the metal tube 1 to support thereon the same. That is, the circular lower lid 3 comprises a circular base (no numeral) and a circular projection 3a coaxially provided on an upper part of the circular base. As shown, the circular projection 3a has a diameter just matched with a lower opening of the metal tube 1. The circular lower lid 3 has a concentric center bore 3b exposed to the interior of the metal tube 1, as shown.
Within the metal tube 1, there is movably received a flexible tube 4 of polyurethane through a tubular rubber seal 5. As shown, the tubular rubber seal 5 entirely covers the cylindrical wall of the flexible tube 4. The flexible tube 4 has an upper open end that is just mated with the smaller-diameter of circular projection 2b of the upper lid 2 and a lower open end that is put on the circular projection 3a of the lower lid 3.
As is seen from FIG. 1, the male die “B” comprises a cylindrical base 6 that has a circular flange 6a integrally formed on a lower end thereof, and three identical flexible molds 7A, 7B and 7C that are piled on one another and put on the cylindrical base 6.
As is seen from FIG. 2, each of the identical flexible molds 7A, 7B and 7C, for example, the flexible mold 7B comprises a flexible cylindrical hollow member 8 made of rubber or the like. As shown, the cylindrical hollow member 8 has a generally cylindrical cavity 8a defined therein. In the illustrated embodiment, the cavity 8a is shaped like a bell. An inner surface of the hollow member 8, that defines the cylindrical cavity 8a, is formed with two diametrically opposed projections 8b. As will become apparent as the description proceeds, due to provision of such diametrically opposed two projections 8b, an insert that is finally produced can have at diametrically opposed portions of the outer surface thereof respective recesses that serve as a rotation stopper when the insert is practically embedded in a cured concrete structure.
A circular lower metal lid 9 is incorporated with a lower open end of the cylindrical rubber hollow member 8 to support thereon the hollow member 8 and close the lower open end, as shown. That is, the circular lower lid 9 comprises a circular base (no numeral), a smaller-diameter upper circular projection 9a coaxially provided on an upper part of the circular base, and a larger-diameter lower circular tapered projection 9b coaxially provided on a lower part of the circular base. As shown, the smaller-diameter upper circular projection 9a is just mated with the lower end of the cylindrical cavity 8a of the rubber hollow member 8.
The circular lower metal lid 9 is formed with a cylindrical recess 9c that extends through a center area of the smaller-diameter upper circular projection 9a to be exposed to the cylindrical cavity 8a of the rubber hollow member 8. The lower metal lid 9 has further a passage 9d that extends downward from the cylindrical recess 9c and terminates at a lower surface of the larger-diameter lower circular tapered projection 9b.
Received in the cylindrical recess 9c of the circular lower metal lid 9 is a lower part of a cylindrical core 10 which is projected into the cylindrical cavity 8a of the rubber hollow member 8, as shown. As will become understood hereinafter, the cylindrical core 10 is used for providing the produced insert with a female thread bore portion.
The cylindrical core 10 comprises a cylindrical base 10a that is received in the cylindrical recess 9c of the lower metal lid 9 and a male thread portion (or externally threaded cylindrical portion) 10b that is integral with and extends upward from the cylindrical base 10a. It is to be noted that the top of the cylindrical core 10 is closed. The cylindrical base 10a has a smaller-diameter lower end portion 10d to define an annular space (no numeral) between a cylindrical inner wall of the cylindrical recess 9c and a cylindrical outer wall of the cylindrical base 10, as shown.
The cylindrical core 10 further comprises an annular flange 10c that is disposed on the cylindrical base 10a. As shown, the annular flange 10c is oriented perpendicular to an axis of the cylindrical core 10.
As shown, the annular flange 10c is intimately put on an upper flat surface of the smaller-diameter upper circular projection 9a of the lower lid 9 and has an outer diameter substantially equal to that of the circular projection 9a. As shown, a periphery of the annular flange 10c is in contact with an inner surface of the rubber hollow member 8.
As will become apparent hereinafter, the outer diameter of the annular flange 10c is larger than an outer diameter of an open end portion of a molded green body of the insert.
A circular upper metal lid 11 is incorporated with an upper open end of the cylindrical rubber hollow member 8 to close the open end. That is, the circular upper lid 11 comprises a circular base (no numeral), a circular tapered projection 11a coaxially provided on a lower part of the circular base and a circular tapered recess 11b coaxially provided on a upper part of the circular base. The circular tapered projection 11a is just mated with an upper end of the cylindrical cavity 8a of the rubber hollow member 8.
It is to be noted that the circular tapered recess 11b receives therein the larger-diameter lower circular tapered projection 9b of the circular lower lid 9 of the upper-positioned flexible mold 7A.
It is further to be noted that upon proper setting the circular upper lid 11 on the rubber hollow member 8, the lower surface of the circular tapered projection 11a is kept away from a top of the cylindrical core 10.
First, the three flexible molds 7A, 7B and 7C are properly set in such a manner as has been mentioned hereinbefore with reference to FIG. 2. That is, in each flexible mold 7A, 7B or 7C, a condition is established wherein the circular lower lid 9 is mated with the lower end portion of the rubber hollow member 8, the cylindrical core 10 is mated with the cylindrical recess 9c of the lower lid 9, the annular flange 10c of the core 10 is in contact with the upper surface of the smaller-diameter upper circular projection 9a of the lower lid 9, and the annular flange 10c of the core 10 is oriented perpendicular relative to the axis of the rubber hollow member 8 and to an axis of the lower lid 9.
Then, as is seen from FIG. 3, the cylindrical cavity 8a of each flexible mold 7A, 7B or 7C is filled with the above-mentioned powdered ceramic material “PCM-0” and then the circular upper metal lid 11 is put on the rubber hollow member 8.
Then, as is seen from FIG. 1, the three flexible molds 7A, 7B and 7C are put on one another and these piled molds 7A, 7B and 7C are set on the cylindrical base 6 to constitute the male die “B”. Although not shown in the drawing, the cylindrical base 6 has at its top a recess that is identical to the above-mentioned circular tapered recess 11b of the circular upper lid 11 (see FIG. 2). Thus, the lower-positioned flexible mold 7C can be stably set on the cylindrical base 6.
Then, as is understood from FIG. 1, the male die “B” is inserted into the female die “A” through the center bore 3b of the circular lower lid 3 of the female die “A” and slid in the female die “A” until the circular flange 6a of the male die “B” is brought into contact with the circular lower lid 3 of the female die “A”. Upon this, the aligned three flexible molds 7A, 7B and 7C are properly received in the flexible tube 4 of the female die “A”.
Then, a hydrostatic pressure of, for example, about 500 Kg/cm2 is applied through the pressure inlet opening 11a to the metal tube 1, more specifically, to a cylindrical space defined between the metal tube 1 and the flexible tube 4. Upon this, the hydrostatic pressure is evenly applied to the flexible tube 4 and thus evenly compresses the flexible tube 4. With this compression, the three flexible molds 7A, 7B and 7C of the male die “B” are evenly pressed compressing the respective rubber hollow members 8.
Thus, as is seen from FIG. 4, the powdered ceramic material “PCM-0” in each flexible mold 7A, 7B or 7C is compressed to produce a molded cylindrical green body “PCM-1” for the insert which is finally produced. As shown, the molded green body “PCM-1” thus produced is shaped like a bell corresponding to the shape of the cavity 8a defined by the hollow member 8.
It is to be noted that upon this molding, due to presence of the cylindrical core 10, a cylindrical bore is produced in the molded green body “PCM-1” thus produced, that is a female thread bore portion (or internally threaded cylindrical portion) 13a intimately engaging with the male thread portion 10b of the cylindrical core 10. The female thread bore portion 13a has one end closed by an end wall portion 13d of the green body “PCM-1”. Furthermore, due to presence of the two projections 8b on the diametrically opposed portions of the hollow member 8, respective recesses 13b are formed on diametrically opposed portions of the cylindrical outer surface of the molded green body “PCM-1”. Denoted by numeral 13c is the most-enlarged annular part concentrically formed on the cylindrical surface of the green body “PCM-1”.
W>Do (1)
W: Diameter of the cylindrical cavity 8a of the hollow member 8 where the projections 8b are formed.
Do: Diameter of the most-enlarged annular part 13c of the molded green body “PCM-1”.
Then, as will be understood from FIG. 1, the male die “B” is removed from the female die “A”, and the three flexible molds 7A, 7B and 7C are detached from the cylindrical base 6 and from one another.
It is now to be noted that the green body “PCM-1” thus naked is shaped like the bell, and has the female thread bore portion 13a, the diametrically opposed two recesses 13b on the cylindrical outer surface of the body “PCM-1”, the most-enlarged annular part 13c and the end wall portion 13d, as shown.
With this baking step, as is seen from FIG. 9A, a final product, that is, an insert “PCM-2” is produced. That is, the insert “PCM-2” thus finally produced is shaped like a bell, and has a female thread bore portion 14a, two diametrically opposed recesses 14b on the cylindrical outer surface of the finally produced insert “PCM-2”, a most-enlarged annular part 14c and an end wall portion 14d, which are baked products of the above-mentioned female thread bore portion 13a, the diametrically opposed two recesses 13b, the most-enlarged annular part 13c and the end wall portion 13d of the cylindrical molded green body “PCM-1”. Denoted by numeral 14e is a chamfered portion provided by the end wall portion 14d.
As is seen from FIG. 9B that shows a front view of the finally produced insert “PCM-2”, the following inequality is established in the finally produced insert “PCM-2”.
d>d1>d2 (2)
d: Diameter at the most-enlarged annular part 14c.
d1: Diameter at the end wall portion 14d.
d2: Diameter of the open side of the insert.
This dimensional inequality (2) is also established in the molded green body “PCM-1”.
First, as is seen from FIG. 10, the finally produced insert “PCM-2”, a holding tube 18 and a rubber packing 17 are aligned on an apertured part of a formwork 15, and then, a connecting bolt 16 is passed through these aligned members and turned about its axis in a connecting direction causing an externally threaded leading end of the connecting bolt 16 to engage with the female thread bore portion 14a of the finally produced insert “PCM-2”. With this, the insert “PCM-2”, the holding tube 18 and the rubber packing 17 are all connected to the formwork as a fixed unit.
Then, as is seen from the same drawing, after the concrete is cured to have a sufficient hardness, the connecting bolt 16 is turned in a disconnecting directing and removed from the insert “PCM-2” together with the rubber packing 17 and the formwork 15. With these steps, the insert “PCM-2” and the holding tube 18 are left and embedded in the cured concrete structure 19 as an insert unit with the female thread bore portion 14a kept exposed to the outside through the holding tube 18.
First, the cylindrical core 10 is equipped with the annular flange 10c. Thus, as is seen from FIG. 4, under molding operation, the annular flange 10c is pressed against the upper end of the circular projection 9a of the lower lid 9 thereby to stably hold the core 10 relative to the flexible mold 7B. This means that the female thread bore portion 14a (see FIG. 9A) produced by the core 10 can have an exact positioning relative to the body of the finally produced insert “PCM-2”. In other words, the female thread bore portion 14a can show a perpendicular positioning relative to the open end surface of the insert “PCM-2”. This feature suppresses or at least minimizes an undesirable matter wherein a connecting bolt for connecting construction parts to the concrete structure 19 fails to correctly engage with the female thread bore portion 14a of the insert “PCM-2”. Furthermore, due to provision of the annular flange 10c of the core 10 (see FIG. 4), the lower lid 9 of the flexible mold 7B (or 7A or 7C) is prevented from directly contacting the molded green body “PCM-1” during the molding process. This is advantageous because a possibility of breaking the open side of the molded green body “PCM-1”during the removal of the core 10 from the green body “PCM-1” is quite lowered. Actually, in the present invention, removal of the core 10 from the green body “PCM-1” is smoothly carried out by turning the core 10.
Second, each of the three flexible molds 7A, 7B and 7C comprises the lower lid 9 with the tapered projection 9b that is to be received in the tapered recess 11b of the upper lid 11 of a different flexible mold and the upper lid 11 with the tapered recess 11b that is to receive the tapered projection 9b of the lower lid 9 of a different flexible mold. Accordingly, as is seen from FIG. 1, the three flexible molds 7A, 7B and 7C can be stably piled on one another and stably put on the base 6 when forming the male die “B”. This stable arrangement promotes the even application of the pressure to the powdered ceramic material “PCM-0” contained in the flexible molds 7A, 7B and 7C, and thus increases the mechanical strength of the molded green body “PCM-1”.
Fourth, as is understood from FIGS. 9A and 9B, the two diametrically opposed recesses 14b of the insert “PCM-2” are positioned in the vicinity of the end wall portion 14d that is away from the open end part of the female thread bore portion 14a. Such positioning of the recesses 14b does not affect the durability of the open end of the female thread bore portion 14a that is highly stressed when a constructional part is connected to the insert “PCM-2” by a connecting bolt. If the two diametrically opposed recesses 14b are positioned near the open end part of the female thread bore portion 14a, the durability of the open end part is reduced.
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