Recyclable plastic man-door

Abstract

A recyclable polyethylene man-door comprises an interior panel and an exterior door panel, each panel having a horizontal pattern of cut-outs and optionally comprising a blend of mineral additives that do not adversely affect the recyclability of the finished product.

Claims

1. A method of manufacturing a polyethylene plastic door comprising: heating a first plurality of polyethylene plastic pellets and polymer additives; extruding a heated mixture of polyethylene plastic pellets and polymer additives to form a first plastic sheet comprising first and second substantially planar surfaces and a second plastic sheet comprising third and fourth substantially planar surfaces; removing from the first substantially planar surface of the first plastic sheet a first plurality of cut-outs; removing from the third substantially planar surface of the second plastic sheet a second plurality of cut-outs, wherein the second plurality of cut-outs mirrors the first plurality of cut-outs; forming a door by attaching the first substantially planar surface of the first plastic the cavity formed by the first plurality of cut-outs and the second plurality of cut-outs form a cavity which is within an interior of the door and the second substantially planar surface of the first plastic sheet and the fourth substantially planar surface of the second plastic sheet form an exterior surface of the door; and recycling a material removed from at least one of the first plurality of cut-outs and the second plurality of cut-outs.

2. The method of claim 1, wherein the step of forming the first plurality of cut-outs is performed using tool paths created by a CNC machine.

3. The method of claim 1, wherein the polymer additives comprise calcium carbonate.

4. The method of claim 3, wherein a resulting composition of calcium carbonate is 15%.

5. The method of claim 1, wherein the step of attaching the first plastic sheet to the second plastic sheet is performed using through bolts.

6. The method of claim 1, wherein a wall-thickness of the first plastic sheet at a respective cut-out is no more than 0.23″ thick.

7. The method of claim 1, wherein a wall-thickness of the second plastic sheet at a respective cut-out is no more than 0.23″ thick.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various aspects and attendant advantages of one or more exemplary embodiments and modifications thereto will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a front perspective of a new interior panel.

(3) FIG. 2 is a front perspective of an exterior panel.

(4) FIG. 3 is a perspective cut-away view of the interior panel.

(5) FIG. 4 is a cross sectional view of the sides of the joined interior and exterior panels.

(6) FIG. 5 is a cross-sectional view of the top of the joined interior and exterior panels.

(7) FIG. 6 is a completed man-door with hardware attached.

DETAILED DESCRIPTION

(8) Exemplary embodiments are illustrated in the referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. No limitation on the scope of the technology that follows is to be imputed to the examples shown in the drawings and discussed herein.

(9) FIG. 1 shows a front perspective of a new interior panel 10 and an embodiment of a horizontal pattern 12. The new interior panel 10 is made up of high-density polyethylene and polymer blend additives. The polyethylene is worked through an extrusion process. In one embodiment, recycled polyethylene plastic pellets are used. In an embodiment, the plastic pellets are within a density range of 0.94 to 0.965 grams per cubic centimeter. The plastic pellets are placed in a funnel and fed into an extruder. The extruder heats the pellets together with a blend of polymer additives. In one embodiment, the polymer blend additive may be calcium carbonate. In certain embodiments, 15% of calcium carbonate is added to the recycled high-density polyethylene to increase stiffness and strength. The addition of a polymer blend additive, such as calcium carbonate will also improve (reduce) thermal expansion/contraction, while not adversely affecting the recyclability of the finished product. In some embodiments, the finished product will have a normal density of 0.99 grams per cubic centimeter.

(10) After the plastic pellets and polymer additive(s) have been heated, a rotating screw forces the raw material blend into an oven. Once in the oven, various sizes of high-density polyethylene plastic sheets are configured through a friction melting process. This results in a high-density polyethylene plastic sheet with an increased thermal range. The reinforced plastic sheet is also more rigid and stable.

(11) Referring to FIG. 1, a horizontal pattern 12 is shown on the front of the new interior panel 10. The horizontal pattern 12 is not centralized to one location. The horizontal pattern 12 is arranged by a series of horizontal cut-outs 11 made across the surface of interior panel 10. Horizontal cut-outs 11 are preferably formed by a CNC machine with a router bit that plunge cuts to a predetermined depth and then follows a tool path without retracting the router bit from the sheet. In certain embodiments, a 1⅜″ diameter router bit is the primary tool used. In certain embodiments, the router bit routs the sheets to a depth of 0.68″. The horizontal cut-outs 11 do not extend fully through the new interior panel 10 and it is important that the horizontal cut-outs leave a sufficient depth of material in the panel. During development, it was determined by the inventors that a remaining wall thickness of 0.19-0.23″ provided the optimal balance between structural integrity and panel weight.

(12) There are preferably two columns, 13 and 14, each with a plurality of horizontal cut-outs 11. In certain embodiments, the columns are spaced 0.96″ apart. During development, it was determined by the inventors that this spacing achieved an optimal balance between the weight of the panel and the beam strength in the width direction.

(13) The horizontal cut-outs 11 are preferably of equal diameter and spaced at equal distance from the neighboring cut-out. In certain embodiments, horizontal cut-outs 11 in the same column are spaced 1″ apart. During development, it was determined by the inventors that this spacing achieved an optimal balance between the weight of the panel and the beam strength in the height direction.

(14) The plastic removed from interior panel 10 when horizontal cut-outs 11 are formed is sent back into the supply chain, thus resulting in a zero-waste production.

(15) The application of the horizontal pattern 12 reduces the plastic sheet's ability to flex. This results in a stronger plastic sheet. The horizontal pattern 12 also reduces the weight of the door. The overall reduction in weight reduces stress on the door panel and associated hardware. The horizontal pattern 12 also increases cycle time of the door.

(16) In some embodiments, a doorknob hole 15 is cut out from the panel. In some embodiments, a plurality of lock holes 16 are cut out above and below the doorknob hole 15.

(17) FIG. 2 shows a front perspective of an exterior door panel 20 and an embodiment of a horizontal pattern 22. The horizontal pattern 22 is made up of horizontal cut-outs 21. In one embodiment, interior panel 10 and exterior door panel 20 are cut so that the horizontal pattern 12 on the interior panel 10 mirrors the horizontal pattern 22 on exterior door panel 20.

(18) FIG. 3 shows a perspective cut-away view of the interior panel 10. The horizontal cut-out 11 does not go through the entire interior side panel 10. Rather horizontal cut-out 11 goes through inner face 30 but does not reach the outer face 40.

(19) FIG. 4 shows a side view of one possible configuration of a partially manufactured man-door 50 comprised of interior panel 10 and exterior door panel 20. The interior panel 10 and exterior door panel 20 are attached so that the horizontal pattern 12 of the interior panel 10 lines up with the horizontal pattern 22 of the exterior door panel 20. In one embodiment, the interior panel 10 is attached to the exterior door panel 20 with through bolts 51 along the perimeter of the door. This configuration increases rigidity.

(20) FIG. 5 shows a top view of one possible configuration of a partially manufactured man-door 50 comprised of interior panel 10 and exterior door panel 20. In an embodiment, two pultruded fiberglass stiffeners, 31 and 32, may be added to the finished door to increase beam strength to the height of the panel. In certain embodiments, the pultruded fiberglass stiffener 31 is 1½″×1½″ and pultruded fiberglass stiffener 32 is ⅝″×1″. The pultruded fiberglass stiffener 32 on the continuous hinge side will decrease the stresses on the through bolts to eliminate plastic deformation of the polyethylene plastic. The pultruded fiberglass stiffeners can be recycled separately from the polyethylene. For example, they may be ground down and used as a filler for concrete.

(21) FIG. 6 depicts an embodiment of man-door 50 where through bolts 51 are evenly spaced around the perimeter of both the interior panel 10 and exterior door panel 20. Other embodiments could use different numbers of configurations of through bolts 51. In another embodiment, there is a doorknob hole 15.

(22) FIG. 6 also depicts man-door 50 with certain elements of hardware and finishing that have been added during manufacturing, including a window 52 and a closer 53.

(23) In summary, the improved polyethylene plastic man-door allows for a polyethylene plastic sheet with increased thermal range, durability, temperature sensitivity and strength, and a reduction in weight. An additional benefit of the improved polyethylene plastic man-door is that it is 100% recyclable. Although the concepts disclosed herein have been described in connection with the preferred form of practicing them and modifications thereto, those of ordinary skill in the art will understand that many other modifications can be made thereto. Accordingly, it is not intended that the scope of these concepts in any way be limited by the above description.