Abstract: The closure includes a bottle cap having a thread on the inner surface of the side wall and a hollow plastic container having an open neck end including a lip region with an outer threaded wall portion extending downwardly therefrom and engagable with the thread on the cap. The lip region includes tapered portions engagable with corresponding tapers on the cap with the lip region placed under stress against the cap.

Abstract: A blow molded, biaxially oriented plastic container with a bottom portion including an axially, inwardly directed generally conical portion, a standing section on which the container rests, a heel portion joining the bottom portion and container body portion, and a hinge portion joining the conical portion and the standing section, wherein the wall thickness of the hinge portion is greater than the wall thickness of the heel portion.

Abstract: The closure includes a bottle cap having a thread on the inner surface of the side wall and a hollow plastic container having an open neck end including a lip region with an outer threaded wall portion extending downwardly therefrom and engagable with the thread on the cap. The lip region includes tapered portions engagable with corresponding tapers on the cap with the lip region placed under stress against the cap.

Abstract: A blow molded, biaxially oriented plastic container with a bottom portion including an axially, inwardly directed generally conical portion, a standing section on which the container rests, a heel portion joining the bottom portion and container body portion, and a hinge portion joining the conical portion and the standing section, wherein the wall thickness of the hinge portion is greater than the wall thickness of the heel portion.

Abstract: A plastic preform for forming blow molded plastic containers wherein the inside wall face of the tubular body portion adjacent the bottom structure and extending onto the bottom structure has a plurality of faces with terminal portions thereof. Scallop-shaped segments are provided connecting the terminal portions of each face to initiate deformation prior to deformation of the faces and thereby have an increased rate and degree of orientation.

Abstract: A plastic preform for forming blow molded plastic containers wherein the inside wall face of the tubular body portion adjacent the bottom structure and extending onto the bottom structure has a plurality of flat faces with terminal portions thereof. Scallop-shaped segments are provided connecting the terminal portions of each flat face to initiate deformation prior to deformation of the flat faces and thereby have an increased rate and degree of orientation.

Abstract: A method for preparing a blow molded plastic container having a thickened bottom structure from a plastic preform. The plastic preform and resultant container have a neck portion defining an opening, a tubular body portion depending therefrom and an integral bottom structure depending from the tubular body portion. A stretch rod is seated inside the preform. The stretch rod stretches the portions of the preform adjacent the bottom thereof by means of a controlled stroke, in an amount less than the amount of stretching of the tubular body portion, to impart to the container bottom structure and adjacent body portions continuous variations of wall thickness the thick parts thereof on average being thicker than the average wall thickness of the container body.

Abstract: A removable insert valve provided with a piston which can be displaced in a bore in a valve housing by pressure fluid action, there being formed at one end of the bore a valve seat and a pressure fluid passage leading through the housing traversely to the bore. The piston is free of O-rings and is provided with first a ledge to constitute a pressure area in the region of the opening of the transverse passage into the bore in combination with a control pressure pump to selectively apply opening and closing pressure to a second ledge on the piston, in order to achieve more rapid operation of the valve.

Abstract: A plastic preform for forming blow molded plastic containers and plastic containers wherein the container has a tubular body portion adjacent a bottom portion and extending onto said bottom portion having circumferentially spaced, radially extending, continuous alterations in wall thickness. In one embodiment the container also includes at least one continuous, thickened portion at discrete locations on at least one of the inside and outside wall face adjacent the bottom structure extending completely circumferentially around the periphery thereof.

Abstract: A plasticizing and melting apparatus for granular synthetic plastic material has a heatable cylinder one end of which has an inlet opening for reception of granular material from an adjustable feeding unit which includes a shaker. The cylinder surrounds a rotary feed screw having a material advancing section in the region of the inlet opening, a first material densifying section immediately downstream of the advancing section, a collar which defines with the cylinder a narrow annular shearing gap immediately downstream of the first densifying section, a pressure relaxing section immediately downstream of the collar, and a second densifying section immediately downstream of the pressure relaxing section. The cylinder has one or more gas evacuating apertures which connect the interior of the cylinder with the atmosphere in the region surrounding the pressure relaxing section.

Abstract: An injection molding machine wherein the ram in the injection cylinder can be moved at several speeds and can be subjected to different fluid pressures by an apparatus having a two-way valve whose inlet is connectable to one or more pumps by way of discrete check valves and whose outlet is connected with a chamber of the injection cylinder by a conduit containing an electrically adjustable pressure relief valve. The valve member of the two-way valve is movable between a first position in which it completely seals the inlet from the outlet and several second positions in which it acts as a flow regulating means to permit the fluid to flow from the inlet to the outlet at a selected rate. The valve member is movable by a solenoid-operated pilot valve which cooperates with a stop extending into the path of movement of the valve member and being movable axially by a reversible motor which is controlled by the programming system of the injection molding machine.

Abstract: A differential piston is reciprocable in a cylinder and subdivides the latter into a first and a second chamber. The piston has a piston rod which extends through the second chamber outside the cylinder and is adapted to open and close the mold of a molding machine. An admitting conduit admits pressure fluid into the first chamber, and a connecting conduit connects the two chambers and has a valve interposed in it so that the two chambers communicate with one another only while the first chamber is pressurized, not while the second chamber is pressurized in the absence of pressure in the first chamber. A sealing arrangement between the piston and an inner circumferential surface of the cylinder is effective for preventing the flow of pressure fluid from the second to the first chamber when the latter is at a lower pressure than the former.