CA2363992A1 - Drop door for packaging container - Google Patents

Abstract

An access feature (drop door) intended to be used in a sleeve-type of packaging container. The invention also pertains to a sleeve-type packaging container which includes one or more such drop doors. Each drop door cooperates with a pair of channels which withhold the door in the closed position yet allow easy lift and pivoting of the door to an open position.

Description

DROP DOOR FOR PACKAGING CONTAINER
FIELD OF THE INVENTION
The invention relates to the structural design of an access feature (drop door) intended to be used in a sleeve-type of packaging container. The invention also pertains to a sleeve-type packaging container which includes one or more such drop doors.
BACKGROUND
Sleeve-type packaging containers are generally composed of 2 plastic pallets and a foldable sleeve (outer shell), of various designs. The vast majority of these sleeve packs are designed to fit 2 wide and 2 or 3 high in a typical truck trailer. Hence sleeve assembly dimensions are likely to be in the 45x48x45" dimensional bracket.
Very often, there is a need for a partial side access to the contents of the pack, with the sleeve set-up and only the top pallet removed. This access is usually provided by a "drop door", defined as a fold-out or pull-out section of the sleeve.
The shape and size of a drop door may vary considerably, but could generally be described as a rectangle with its horizontal dimension less than half the length of the corresponding side panel and its height up to half the useable height of the same panel. A common door size for one of the above mentioned sleeve packs would be 20x20", for example.

A pack may have 1 or 2 drop doors, typically centered left to right and located at the upper edge of the (opposite) side panels.
Existing packaging designs feature drop doors defined by 2 vertical cuts and one or two horizontal score-lines, as hinges. Problems: The sleeve material, usually paper or plastic corrugated, retains most of its memory at the score level (generally vertical flute orientation) and the drop door (or access flap) tends to either "spring" back toward its upright position when open, or flap out from its vertical position when closed. Either way, misalignments are likely to occur. Also, a hand-hole feature is usually needed for drop door operation.
Last but not least, a container with drop doors) loses part of its stacking strength and side-panel rigidity, due to obvious material discontinuity.
Other previous drop door designs feature a completely separate, removable panel, that can slide in and out vertical channel guides. Problem: The panels) are lost or their tethering becomes an impractical hazard.
The challenge became to develop a drop door that would have a clearly defined upright (closed) position and a 180 degrees opposite (open) position, while remaining permanently attached to the sleeve, minimizing the stacking and side-rigidity strength reduction, and eliminating the need for a hand hole.

SUMMARY of the INVENTION
The proposed design solution features a slide & hinge combination access panel (door), that operates in 2 positions: up (closed) and down (open).
BRIEF DESCRIPTION OP THE DRAWINGS
Fig. 1 is a perspective view of the drop door according to the invention;
Fig. 2 is a perspective view of a packaging sleeve on a pallet incorporating a pair of drop doors which are shown as open or down;
Fig. 3 is a blank design for the length panel of the sleeve pack showing that the removed section can be used to make the drop door panel;
Fig. 4 is a blank design for the width panel of the sleeve pack;
Fig. 5 is a top view of the sleeve comprising a pair of width panels (Fig. 4) and a pair of length panels (Fig. 3);
Fig. 6 is a cross-sectional view of an exemplary door channel (H-channel) extrusion;
Fig. 7 is a front view of the door panel having disposed therein the pins/rods;
Fig. 7A is a front view of the door panel disposed within its vertical channels and showing the optional horizontal c-channel;

Fig. 8 shows a closeup of the notched upper portion of the H-channel and the drop door in its closed position;
Fig. 9 shows a closeup of the lower end of the H-channel with the drop door in its open position; and Figs. 10-13 illustrate the operation of the drop door in situ in the sleeve pack.
DETAILED DESCRIPTION
The typical sleeve pack comprises a sleeve made of suitable material such as corrugated cardboard or corrugated/fluted plastic (polypropylene for example), and an upper and lower pallet. [Fig. 10]
Foor the drop door, a rectangular panel, with horizontal corrugation, is fitted with 2 pairs of pins: 2 upper pins and 2 lower pins. These pins are horizontal, and may be designed as the protruding tips of 2 cylindrical rods installed approximately 1" from the top and the bottom of the door panel, inside the fluted material. [Figs. 1, 3 and 7]
These pins slide into 2 vertical channels, part of a custom extruded profile resembling a modified "H" shape (cross section). [Fig. 6] The channel may be made from any suitable material, such as polypropylene. The top portion of the outside wing of the sliding channel is notched [Figs. 1 and 8], allowing the upper pair of pins (rod) to disengage the channel toward the outside of the pack, when the door is lifted about 1" from its closed position.
[Fig. 11]

This upward movement is prevented during transport by the top pallet. [Fig.
10]
The lower pair of pins (rod ends) remains inside the channel at all times. It acts as a sliding mechanism for the up & down motion of the door, and as a hinge for the outward, 180 degrees rotation of the door, once the upper pins (rod) have cleared the channel profile (at the notch level).[Figs. 1, 2 and 9 to 13]
The assembly of the 4-pin door in the channel-fitted sleeve is achieved with 2 pairs of stop pins or rivets, that capture the lower door pins inside the corresponding channels, while allowing sufficient vertical play for the lower pins between the stop pins. The play enables the top door pins to slide out of the notched upper portion of the channel to thereby the door panel to rotate freely around the bottom rod (pins) axis. [Figs. 1, 7 and 7A]
The other 2 vertical channels, as part of the modified "H" section extrusion, fit and are fastened with rivets over the 2 vertical edges of the door cut (opening) in the side-panel. If desired, a third channel can be provided for the horizontal span between the two H-channels. [Figs. 1, 7 and 7A]
The assembly offers clear and easy access to the inner volume of the pack.
It also provides stacking support through the added vertical channels, that compensate for the missing door material in the wall of the sleeve.
The horizontal corrugation of the door panel and the natural reinforcing provided by the pin-rods, contribute to alleviate side-deflection in the access door panels.

The unique slide & hinge features described above offer the operators maximum access to the inside and around the sleeve pack, minimizes the risks of door "catching" of interference, while maintaining the pack's collapsible features.
While the foregoing has described and illustrated a novel drop door system for use with sleeve-type packing containers, it will be appreciated that the principles and structures can be applied to the packaging of various other products. It will also be appreciated that various modifications and adaptations can be made without departing from the spirit of the invention as described herein.

Claims (2)

1. A drop door for a packaging container as described and illustrated herein.

2. A packaging container having one or more drop doors as described and illustrated herein.