Method of forming non-skid plastic pallet

• US 5,993,724 A
• Filed: 12/31/1997
• Issued: 11/30/1999
• Est. Priority Date: 12/31/1997
• Status: Expired due to Fees

• Current Assignee: Lyle H. Shuert
• Original Assignee: Lyle H. Shuert
• Inventors: Shuert, Lyle H.
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): LEE, DAE Y
• Application Number:
  US09/002,095
• Time in Patent Office: 699 Days
• Field of Search: 264/545, 264/553, 264/296, 264/322, 264/248, 156/292, 425/503, 425/504, 425/515
• US Class Current: 264/545
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 51/267 Two sheets being thermoformed in separate mould parts and joined together while still in the mould B29C49/0691 takes precedence
• CPC Class Codes: B29C 59/02 by mechanical means, e.g. pressing B29C59/007 takes precedence; embossing expanded porous articles B29C44/5627
• CPC Class Codes: B29C 59/022 characterised by the disposition or the configuration, e.g. dimensions, of the embossments or the shaping tools therefor
• CPC Class Codes: B29C 66/305 Decorative or coloured joints optical properties of the material of the parts to be joined B29C66/733
• CPC Class Codes: B29L 2031/7178 Pallets

Abstract

A first mold is provided having a first molding surface including a flat primary surface area, a plurality of spaced leg areas within the primary surface area, and a plurality of pin holes in the primary surface area positioned between the leg areas; and a second mold is provided having a second molding surface including a flat primary surface area, a plurality of leg areas in the primary surface area corresponding to the leg areas in the primary surface area of the first molding surface, and a plurality of spaced knitting surfaces relieved from the general plain of the primary surface area, positioned between the leg areas, and corresponding to respective pin holes in the primary surface area of the first molding surface. A first plastic sheet is thermoformed to the first molding surface to conform the first plastic sheet to the primary surface area and the leg areas of the first molding surface and position the sheet in overlying relation to the pin holes. A second plastic sheet is thermoformed to the second molding surface to conform the second plastic sheet to the primary surface area, the leg areas, and the knitting areas of the second molding surface. The molds are brought together to bring respective knitting surfaces of the second molding surface into proximity with respective pin holes in the first molding surface and the molds are thereafter pressed together to force plastic material into and fill the pin holes in the first molding surface.

Claims

1. A method of forming a twin sheet plastic article comprising;

providing a first mold having a first molding surface including a large generally planar feature and a plurality of detail features within the large feature;

providing a second mold having a second molding surface including surface areas corresponding spatially to the detail features of the first molding surface;

thermoforming a first plastic sheet to the first molding surface with a thermoform pressure sufficient to provide conformance of a planar surface of the first sheet to the large generally planar feature but insufficient to provide conformance of the planar surface of the first sheet to the detail features;

thermoforming a second plastic sheet to the second molding surface;

bringing the molds together to bring the thermoformed first and second sheets together and bring respective surface areas of the second molding surface into proximity with respective detail features of the first molding surface; and

thereafter pressing the molds together to force the thermoformed first and second sheets together and force plastic material into conformity with the detail features to form relieved areas on the planar surface of the first sheet providing an anti-skid characteristic for the planar surface.

2. A method according to claim 1 wherein;

the generally planar feature comprises a large area flat surface;

the detail features comprise a plurality of small spaced pockets in the flat surface; and

the surface areas of the second molding surface comprise spaced individual areas which are relieved with respect to the general plane of the second molding surface and which knit to the first plastic sheet at the pockets in the first molding surface and act to force plastic material into the pockets to fill the pockets.

3. A method according to claim 2 wherein;

the planar surface of the first sheet defines an upper support surface in the finished article; and

the pockets define pin holes in the first molding surface so that the filled pockets define pins upstanding from the upper support surface of the finished article.

4. A method according to claim 3 wherein the spaced individual areas of the second molding surface are defined by spaced knob structures outstanding from the general plane of the second molding surface.

5. A method of forming a twin sheet plastic panel comprising;

providing a first mold having a first molding surface including a large flat primary surface and a plurality of spaced small pockets in the primary surface;

providing a second mold having a second molding surface including a large flat primary surface and a plurality of small knitting surfaces relieved from the general plane of the primary surface;

thermoforming a first plastic sheet to the first molding surface with a thermoformed pressure sufficient to provide conformance of a planar surface of the first sheet to the primary surface of the first molding surface but insufficient to provide conformance of the planar surface of the first sheet to the pockets;

thermoforming a second plastic sheet to the second molding surface to conform the second sheet to the primary surface of the second molding surface and to the knitting surfaces of the second molding surface;

bringing the molds together to bring the thermoformed first and second sheets together and bring respective knitting surfaces of the second molding surface into proximity with respective pockets in the first molding surface; and

thereafter pressing the molds together to force plastic material into and fill the pockets in the first molding surface to form relieved areas on the planar surface of the first sheet providing an anti-skid characteristic for the planar surface.

6. A method according to claim 5 wherein;

the plane surface of the first sheet defines an upper surface in the finished panel; and

the pockets define pin holes in the primary surface of the first molding surface so that the filled pockets define pins upstanding from the upper surface of the finished panel.

7. A method according to claim 6 wherein the small knitting surfaces of the second molding surface are defined by spaced knob structures upstanding from the general plain of the primary surface of the second molding surface.

8. A method of forming a twin sheet plastic pallet comprising;

providing a first mold having a first molding surface including a flat primary surface area, a plurality of spaced leg areas within the primary surface area, and a plurality of pin holes in the primary surface area positioned between the leg areas;

providing a second mold having a second molding surface including a flat primary surface area, a plurality of leg areas in the primary surface area corresponding to the leg areas in the primary surface area of the first molding surface, and a plurality of spaced knitting surfaces relieved from the general plain of the primary surface area, positioned between the leg areas, and corresponding to respective pin holes in the primary surface area of the first molded surface;

thermoforming a first plastic sheet to the first molding surface with a thermoform pressure sufficient to provide conformance of a planar surface of the first plastic sheet to the primary surface area and the leg areas of the first molding surface but insufficient to provide conformance of the planar surface of the first plastic sheet to the pin holes;

thermoforming a second plastic sheet to the second molding surface to conform the second plastic sheet to the primary surface area, the leg areas, and the knitting areas of the second molding surfaces;

bringing the molds together to bring the thermoformed first and second sheets together and bring the respective knitting surfaces of the second molding surface into proximity with respective pin holes in the first molding surfaces; and

thereafter pressing the molds together to force plastic material into and fill the pin holes in the first molding surface to form Pins on the planar surface of the first sheet providing an anti-skid characteristic for the planar surface.