Patent Application
20080308555
There are no related applications.
This invention relates to a shipping and storage drum and, more particularly, to a drum with a screw on locking cover.
In one form of a conventional shipping and storage container, an enlarged drum is used. The drum may be, for example, a 55 gallon drum. Such drums have found wide usage for shipping and storing liquid or granular products. For example, such drums have been used for storing food products and for storing hazardous products.
A typical drum includes a tubular sidewall closed at one end by a bottom wall and at another end by a top wall. Such containers may have a fiberboard sidewall and metal top and bottom walls, may be made entirely of metal, or may be made entirely of plastic, or be of composite construction. Drums of fiberboard are generally not suitable for carrying liquids. While metal drums are, they tend to be expensive and heavy and are not usable in the food industry unless made of stainless steel.
Such drums are classified as open head drums or tight head drums. With a tight head drum, the top wall is generally permanently affixed to the sidewall. The top wall includes relatively small openings for access to the interior of the drum. Conversely, an open head drum has a cover removably received thereon. Typically, the container is filled by removing the cover.
More recently, plastic drums have found wide acceptance. Customers often desire that the drum be a one-piece drum having an integral cover. However, such a drum is typically made by blow molding, which is a time consuming and expensive process. Also, the drums tend to be of lesser quality as there may not be uniform distribution of the plastic material.
Even more recently, threaded drum plastic covers have been provided for selectively closing a unitary plastic open head drum to effectively provide a tight head drum. Such a drum and cover are illustrated in U.S. Pat. No. 6,056,143. This patent includes a continuous thread on the drum. Multiple turns of the cover must be made to effectively secure the cover on the drum, with a gasket providing a seal.
The present invention is directed to further improvements in shipping and storage drums.
In accordance with the invention, there is provided a screw on drum cover for selectively closing an open head drum with a fractional turn of the cover.
Broadly, there is disclosed herein a shipping and storage drum comprising an open head drum and a plastic cover. The open head drum comprises a sidewall open at a top end by a threaded plastic chime. The chime comprises an annular wall having a rounded top edge with a plurality of thread segments extending outwardly from the annular wall. The thread segments are circumferentially spaced by non-threaded portions. A circumferential length of each non-threaded portion is similar to a circumferential length of each thread segment. The plastic cover has a central circular wall surrounded by a downwardly opening generally U-shaped wall for receiving the chime. The U-shaped wall comprises an outer annular sidewall and an inner annular sidewall connected by a rounded channel for sandwiching the chime. The outer annular wall has a plurality of inwardly extending thread segments. The thread segments are circumferentially spaced by non-threaded portions. A circumferential length of each non-threaded portion is similar to a circumferential length of each thread segment. The cover is selectively screwed onto the chime with a fractional turn of the cover and the chime rounded top edge is sealed in the rounded channel.
It is a feature of the invention that the drum chime and the cover each include eight thread segments.
It is another feature of the invention that each drum chime and cover thread segment comprises three threads.
It is a further feature of the invention that each chime thread segment comprises a stop for limiting threaded movement of the cover onto the chime.
It is still another feature of the invention that the drum further comprises a flange extending outwardly from the annular wall below the thread segments and the cover comprises a flange extending outwardly from the outer annular sidewall. Aligned openings are provided in each of the flanges and a locking member is provided for insertion in the openings to lock the cover on the drum.
It is still another feature of the invention that the inner annular sidewall comprises a plurality of outwardly extending ribs.
It is an additional feature of the invention that the chime rounded top edge seals against each of the outer annular sidewall and the inner annular sidewall.
It is still a further feature of the invention that the threads have about a ¼″ pitch.
It is yet another feature of the invention that the chime has a diameter of at least about 15″.
There is disclosed in accordance with another aspect of the invention a shipping and storage drum with a screw on locking cover comprising an open end drum, a plastic cover and a locking member. The open head drum comprises a sidewall open at a top end by a threaded plastic chime. The chime comprises an annular wall having a rounded top edge with a plurality of thread segments and a flange extending outwardly from the annular wall below the thread segments and having a flange opening. Each thread segment comprises a plurality of threads extending outwardly from the annular wall. The thread segments are circumferentially spaced by non-threaded portions. A circumferential length of each non-threaded portion is similar to a circumferential length of each thread segment. The plastic cover has a central circular wall surrounded by a downwardly opening generally U-shaped wall for receiving the chime. The U-shaped wall comprises an outer annular sidewall and an inner annular sidewall connected by a rounded channel for sandwiching the chime. A flange extends outwardly from the outer annular sidewall and has a flange opening. The outer annular wall has a plurality of inwardly extending thread segments each having a plurality of threads. The thread segments are circumferentially spaced by non-threaded portions. A circumferential length of each non-threaded portion is similar to a circumferential length of each thread segment. The cover is selectively screwed onto the chime with a fractional turn of the cover with the chime rodded top edge being sealed in the rounded channel. The locking member is insertable through the flange openings to prevent the cover from backing off of the drum.
Further features and advantages of the invention will be readily apparent from the specification and from the drawings.
In the illustrated embodiment of the invention, as disclosed in the drawings, a shipping and storage container 20 is shown to comprise a unitary plastic open head drum 22 and a unitary plastic threaded drum cover 24. With reference to
The wall thickness of the chime annular sidewall 36 may be slightly greater than the wall thickness of the sidewall 26. However, the drum includes a seamless, continuous inner surface 44 between the chime annular wall 36 and the sidewall 26. A flange 46 extends outwardly at a junction between the annular wall 36 and the sidewall 26. A plurality of support ribs 48 extend outwardly from the sidewall 26 and are connected to the underside of the flange 46.
In the illustrated embodiment of the invention, the drum 22 is of one piece molded plastic construction and may be formed of polypropylene or polyethylene or the like. As will be apparent, the drum 22 could be a composite structure using fiberboard or metal, or the like, with a plastic chime secured thereto in any known manner. The drum 22 is adapted for storage of bulk materials and would typically have a dimension in the range of 15-½″ to 23-½″ diameter at the top end 32.
In the illustrated embodiment of the invention, there are eight thread segments 40 separated by eight non-threaded portion 42. Each thread segment would use up approximately 22.5° of circumference. Advantageously, the thread segments may use a slightly smaller amount such as about 21°. However, the lengths could be different, as could the number of thread segments 40. Each thread segment 40 comprises three threads 40-1, 40-2 and 40-3, see
Referring to
Referring particularly to
Spacing between the cover outer annular sidewall 58 and inner annular sidewall 60 is greater than thickness of the drum chime 34. A plurality of ribs 76 are provided in the U-shaped wall 56 extending outwardly from the inner annular sidewall 58, see
Corresponding to the drum thread segments 40, each cover thread segment 72 includes three threads 72-1, 72-2 and 72-3, see
For preventing the cover 24 from backing off the drum 22, an opening 78 is provided in the cover flange 68 having a size corresponding to that of the drum flange openings 52. A circular opening 80 is provided through the upper wall 64. Referring to
The use of a broken thread in the form of a plurality of thread segments allows for less than a full turn to close the cover 24 on the drum 22 providing ease of use. A locking feature is retained by use of the locking member 82. Moreover, the drum 20 is self sealing. The drum is illustrated with eight flange openings 52, one for each thread segment 40. This enables the cover 24 to be threaded at any of eight angular positions. As is apparent, the drum could include a single opening 52 or the cover could include as many as eight angular openings 78, as necessary or desired. The locking member 82 is not required for performance, but is used to prevent the cover 24 from backing off the drum 22, as described.
Thus, in accordance with the invention, there is provided a shipping and storage drum wherein a cover is selectively screwed on with a fractional turn and providing a self sealing feature.
