GB2220611A

GB2220611A - Plastic box welding process

Info

Publication number: GB2220611A
Application number: GB8812750A
Authority: GB
Inventors: Barry Francis Strong
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-28
Filing date: 1988-05-28
Publication date: 1990-01-17
Also published as: GB8812750D0

Abstract

A plastic fabrication/welding process used in load bearing plastic box manufacture is disclosed. The handled sides and base of the box are of one continuous sheet 1 grooved along the sheet at the positions where the sheet is to be bent (see figure 2). The groove lengths are hot wire or hot blade heated, then bent so that the groove closes and re-welds itself into a continuous homogeneous molecular structure. After completing all the grooves the box sides 2 and 3, cut from plastic sheet, are fitted to sheet 1 using e.g., hot plate welding to form the box shown in figure 1. <IMAGE>

Description

DESCRIPTION PLASTIC BOX WELDING PROCESS Technical Field This invention relates to Load Bearing Plastic Fabricated Box 5.

Background Plastic boxes are well known structures made in the past by hot forming using positive pressure moulds and or negative pressure (vacuum) forming, larger boxes have been fabricated using sheet plastic cut to size and welded screwed or glued together.

Moulding and forming are relatively expensive processes for low volume production, and previously referred to fabrication methods have lacked load bearing characteristics expected with larger boxes used to carry dense products ie:- lead acid batteries for example.

Essential Technical Features In this invention the box sides embodying the handles and the base of the box are made from a continuous piece of sheet plastic, the sides not containing the handles are then attached using conventional means.

Example A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the finished box in perspective, by line drawing.

Figure 2 illustrates by exaggerating the plastic sheet thickness, the components from which the box is made.

Figure 3 shows the forming of the base and the sides.

Referring to the drawing the box comprises of a continuous sheet 1 having a handle at each end, and two end pieces 2 and 3, cut from plastic shee-t of suitable thickness.

Grooves are cut in sheet 1 the position, number and angle of which are determined by the shape and size required of the finished box, the example shown has three grooves see figure 3 The grooved surface of the sheet is precisely heated using a concentrated heat source not shown but of the hot wire or knife type, oxidation must not be allowed to take place during this heating process.

Sheet 1 is then bent to close the groove making a continuous weld along the groove allowing inside contours of the box to be sharply defined as required, see figure 3.

The ends are then fitted using hot plate welding or other process not shown to complete the product see figure 1.

Claims

1. A load bearing Plastic Welded Joint with plastic molecular continuity across the joint.

2. A box fabricated using joints as Claimed in 1.

having homogeneous tensile strength along its planes of tension perpendicular to the joints in its handled sides and base.

3. A joint as claimed in Claim 1 with inside corner sharply profiled.

4. A box with joints claimed in 3. with inside corners sharply profiled so to accommodate the external profiles of that which it is to contain.