摘要:
A concrete conduit is completely encased within a shell of a plastic resin such as polyethylene. The plastic shell functions to insulate the concrete conduit from mechanical shocks thereby preventing breakage and cracking of the conduit. The shell also effectively provides an impermeable barrier for water vapor and a smooth, relatively frictionless, surface for receiving electric cables, wires and the like. The conduit is made by preforming the shell, for example by rotational molding, and filling the shell with pourable cement through a filler hole in the shell. The filler hole can then be closed with a plug of the resin used to form the shell.
摘要:
An integral double-wall container, made of a synthetic plastic, for handling bulk materials such as liquids and powder, and adapted to be lifted and moved by means of a forklift truck. An integral one-piece double-wall hopper bin for dispensing liquid and powder. A method of making integral double-wall containers and hopper bins by rotational molding.
摘要:
A technique for the rotational molding of hollow articles having separate but structurally integral compartments is described. A mold in which the article is to be formed is provided with a cover between the mold cavities in which the article compartments are to be rotationally molded. The cover is selectively spaced from the mold wall so that a thermoplastic resin used to form the article can pass through the space between the cover and the mold wall to form the article walls for the compartments. The cover spacing from the mold wall is so selected that the build-up of the article's wall eventually seals off this spacing and enables further rotational molding of an article wall over the cover to isolate the compartments. In the specific embodiment, a technique for the rotational molding of a tank with legs below a bottom wall and a continuous uninterrupted interior bottom surface is described.
摘要:
Systems and methods for fabricating indirect bonding trays are disclosed. Physical models of a patient’s teeth can be created with non-functional placeholder brackets, impressions of which can be transferred to indirect bonding trays. This can create wells in which functional brackets can be placed into, reducing errors created from transferring functional brackets from the physical model onto the indirect bonding trays.
摘要:
IN THE NANUFACTURE OF CYLINDERS COMPRISING TWO CONCENTRIC CYLINDRICAL SHELLS WITH AN INTERPOSED CORE COMPRISING RADIALLY EXTENDING GAS-FILLED CELLS A THIN SUPPORT LAYER WHICH IS POROUS TO THE MATERIAL FROM WHICH THE INNER SHELL IS SPUN CAST IS APPLIED TO THE INNER FACE O THE CORE AND THE INNER SHELL IS SPUN CAST AGAINST THE SUPPORT LAYER.
摘要:
Devices and methods are provided for making a variable textured breast implant when used in conjunction with a breast implant mandrel having a molding surface and a stem depending therefrom.
摘要:
A molding system for molding hollow bodies and an article, such as a pallet, produced by means of such system. In a preferred form, the pallet is a rectangular parallelepiped hollow molding and is specifically shaped during molding, to be substantially stiffened by means of its shape and to receive and support one or more blades of a lifting and handling device. In one form, one or more stiffening members extend across the hollow molding and are retained therein as a result of having the molding material molded about the stiffening members. In another form, two stiffening members are provided, each extending along a respective border portion of the hollow molding parallel to the other stiffening member. The invention is also concerned with a method for molding large hollow bodies by means of a fast setting resin which is premixed just before it is introduced into a mold.
摘要:
A method of molding an article between a pair of spaced molded walls comprises the steps of releasably attaching a first member to one mold wall, releasably attaching a second member to the other mold wall in alignment with but spaced from the first member, connecting the two spaced members together by a yielding connection, and introducing heated molding material between the two mold walls, whereby when the molded article cools, the yielding connection yields to accommodate shrinkage deformation of the article. Also described is apparatus for use in performing the above method.