Sonoco Products Company

Greif Bros. Corp. of Ohio, Inc.

Russell-stanley Corporation

John H Malik

John J Mikula

Robert Alan Julien

Patrick E Irwin

William C Fields

Floy C Jones

A one piece thermoplastic tighthead drum having a drum body, a bottom, a top and at least one handling ring, at least one of said top and/or bottom including a raised central section surrounded by an annular groove defined by a groove floor, a first sidewall connecting the groove floor and the raised central section and a second sidewall comprising at least a portion of the handling ring. The drum body, the top and/or bottom having the handling ring associated with it and the handling ring converge in an area of merger, the interior surface of which comprises a smooth undulating surface having at least four radii. The configuration provides a double hinge for minimizing the effects of drop impact in the area of merger.

Tighthead drum

A one-piece blow-molded closed plastic drum having an integrally-formed compression-molded handling ring and method of molding same is provided. The drum has structural strength and stability to resist breakage of the drum upon impact due to tipping or dropping of the drum. The drum includes a generally cylindrical body portion and a head portion integrally-molded with an upper end of the body portion including a transition area around and between the upper end of the body portion and a top of the drum in the head portion. The transition area has an outside curved surface of a predetermined radius so that an outside surface of the body portion is positioned in a tangential plane in close proximity to a tangential plane along the outer circumferential surface of the handling ring and/or an inside curved surface with at least one radius, preferably a double ogee with three predetermined radii, so that no acute angles are formed between inside surfaces at the transition area.

One-piece blow-molded closed plastic drum with handling ring and method

A closed one-piece plastic drum having an integral handling ring at a head end is formed in a blow mold having mold halves and an articulating mold section. While the mold is open and the articulating section is spaced from the mold halves, a heated plastic parison is placed in the open mold and blown at a first blowing pressure (30-60 psi) to completely expand the parison into the shape of the inside surface of the mold and fill the open articulating section. This blow molding step forms an open handling ring as well as the drum body. A second blowing operation at a second lower pressure (15-40 psi) is then performed to stabilize the expanded parison inside the mold. The mold articulating section is closed during the second blowing operation in first and second sequences. In each sequence, the articulating section is moved over a different distance and at a different speed while compressing the blow-molded open handling ring into a solid handling ring. After the articulating section is completely closed, a third blowing operation at a third pressure (90-110 psi) is performed. The third pressure is higher than both the first and second pressures and is held for a sufficient time to allow cooling of the molded plastic drum.

Blow molding a closed plastic drum including two speed compression

An integrally molded plastic drum having a cylindrical body, a top wall, and a bottom wall is provided. The bottom wall has a central recessed portion and an annular generally flat horizontal bottom wall portion surrounding the central recessed portion. The annular bottom wall portion has a first recess, a second recess, and a discrete hand engageable lifting indentation therein. The central recessed portion, first and second recesses, and the discrete lifting indentation collectively contain the molding parting line extending across the bottom wall of the drum. The top wall of the drum has a central concave portion which serves as a collection well in the event of spillage and also serves to facilitate the drainage of the drum when the drum is inverted. The top wall defines a pair of spaced apart bungholes therein. The bungholes are positioned in a diametrically opposing relation, with one of the bungholes serving as a filling spout and the other bunghole serving as a pouring spout. The top wall defining the pair of bungholes also defines internal threads for each bunghole, where the internal threads for the pouring spout are coarser than the internal threads for the filling spout. The discrete hand engageable lifting indentation is positioned directly below the filling spout and is of such a size as to be easily grasped by one's hand for manual lifting of the drum.

Growing community of inventors

Naperville, IL, United States of America

John H Malik