Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reexamination Certificate
1999-02-17
2001-01-30
Vargot, Mathieu D. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C264S138000, C264S274000, C264S275000, C264S333000
Reexamination Certificate
active
06180046
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to method and apparatus for producing wire reinforced cast members and more particularly to such method and apparatus utilizing wire reinforcement support members which support and accurately position the wire reinforcements, and having a mold mounting portion which readily breaks away from the mold members when the cast member has set and is removed from the mold.
BACKGROUND OF THE INVENTION
The conventional technique for producing cast members such as manhole assemblies comprises the steps of pouring the cast material, i.e. concrete, into a mold containing a cylindrical shaped grid of wires placed within the mold and serving as a reinforcement for the cast member. The wire grid typically comprises a plurality of vertically aligned wires joined to horizontally aligned hoops, forming the grid-like framework. When the cast material is set, the cast member is removed from the mold. The wire reinforcement is embedded in the cast material, typically concrete.
Investigation and analysis by the authorities responsible for establishing specifications for manhole assemblies have recently developed new specifications, which permit the use of one or more lines of hoop steel in place of the grid-like wire mesh of conventional design. These new specifications result from the fact that once manhole assemblies are installed, they are in compression whereas reinforcement steel has been utilized in concrete to provide reinforcements for a cast member under tension.
Thus, the new specifications require that circular manholes need only be provided with steel reinforcement satisfactory for handling purposes preparatory to in-ground installation with the result that the new specifications permit manhole assemblies of certain sizes and thicknesses to have a reduction in reinforcement steel content enabling the use of round steel hoops in the place of conventional steel mesh (i.e. welded wire fabric arranged in a grid-like pattern). In view thereof, it is necessary to provide proper support, alignment and positioning of the steel hoops in place of the conventional longitudinal elements used in conventional designs and which are no longer required.
BRIEF DESCRIPTION OF THE INVENTION
The present invention is characterized by comprising method and apparatus for producing steel reinforced cast members such as manhole assemblies and the like comprised of the steps of providing openings along one of the manhole mold members for supporting spacers; inserting projections provided on the spacers into the mounting openings provided therefor and positioning the steel hoops into recesses (i.e. holding portions) provided within each of a group of preferably equi-spaced hoop supports arranged about the periphery of a mold member to support and accurately position the steel hoops; pouring the concrete into the mold; allowing the cast material (concrete) to set; and removing the cast member from the mold when the cast material has set, whereupon the projections of the hoop supports break away from the main body thereof preferably along shear lines provided in the supports, the main body of the supports being embedded within the cast member.
Each of the supports is comprised of a body portion, preferably having a pair of projections for insertion into a pair of mounting openings in the mold member. The projections, in one preferred embodiment, preferably have an oversized flange portion which is force-fitted into the support openings to adequately retain the supports in position, unaffected by the pouring of the concrete into the mold.
Each support in said one preferred embodiment, is provided with an oblong recess which opens into an upper side of the support. The recesses each receive a portion of the steel hoop which is formed of a single loop of metal wire having a substantially circular cross-section. However, hoops of other cross-sectional configurations (rectangular, square, polygonal, etc) may be employed. The steel wire is snap-fitted into the recess and is retained and accurately positioned therein, and is unaffected by the pouring and setting of the concrete, thereby assuring proper positioning of the steel hoop within the cast member.
It is preferable to provide three (3) or more supports arranged at substantially equi-spaced intervals about the mold member to provide proper support for a steel hoop.
The supports are preferably provided with a pair of projections, which extend into the support openings to prevent the supports from twisting or turning during the casting process.
The supports are preferably formed of a suitable plastic or like material. Plastic is preferred as it is non-corrosive and can be designed of a durometer that is resilient enough for an easy force-fit, but brittle enough to readily break at shear points and are provided with a shear portion or line, preferably of a reduced thickness at a position slightly displaced from the projections inserted into the support openings in the mold member enabling the projections to easily and cleanly break away from the main body portion of the support when the cast material has set and the cast member is removed from the mold, the main body portion being retained embedded within the cast member.
Although the preferred embodiment preferably has a pair of projections inserted into openings provided within the mold member, one elongated projection may be provided as an alternative arrangement for providing the desired support and preventing turning of the support within the mold.
The supports are preferably produced by an injection molding process, and are formed as a unitary, one-piece structure. Alternatively, a support may be formed of a body member having bores for receiving projections which are force fitted into the bores.
The projections, in said one preferred embodiment, may be rod-shaped and extend into openings of a conforming size and shape for force-fittingly receiving the projections.
In another preferred embodiment, the projections are flange-like in nature and are arranged to fit into elongated slots which are wider at an insertion end and narrower at a locking end. The flanges are inserted into the wider ends of the receiving slots and are moved so as to slide along the receiving slots into the locking portions thereof. The flanges of the supports break away from the main body thereof in much the same manner as the first mentioned preferred embodiment.
OBJECTS OF THE INVENTION
It is therefore one object of the present invention to provide novel method and apparatus for forming manhole assemblies and the like and in which novel support members are utilized to support and accurately position metal reinforcement hoops during the casting process.
Still another object of the present invention is to provide novel method and apparatus for casting steel reinforced concrete members employing novel support members for supporting and accurately positioning steel reinforcement hoops within the cast member, said support members being designed to simply and readily mount to a mold member employed in the casting process.
Still another object of the present invention is to provide novel method and apparatus for casting steel reinforced concrete members employing novel support members for supporting and accurately positioning steel reinforcement hoops within the cast member, said support members being designed to simply and readily mount to a mold member employed in the casting process, and further having shear points which cause the portion of the support member extending out of the cast member to easily break away from the main body portion which is embedded in the cast member.
Still another object of the present invention is to provide novel method and apparatus for casting steel reenforced concrete members employing novel support members for supporting and accurately positioning steel reinforcement hoops within the cast member, said support members being designed to simply and readily mount to a mold member employed in the casting member and having flanges which slide into cooperating slots
Ditcher Scott
Kelly Robert M.
Atlantic Precast Concrete Inc.
Vargot Mathieu D.
Volpe and Koenig P.C.
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