Plastic lumber pallets

• US 6,524,426 B1
• Filed: 06/15/2000
• Issued: 02/25/2003
• Est. Priority Date: 06/15/1999
• Status: Expired due to Fees

• Current Assignee: Edison Welding Institute Incorporated
• Original Assignee: Edison Welding Institute Incorporated
• Inventors: St. John, Marc A., Hartke, Kevin M.
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): KOPPIKAR, VIVEK D
• Application Number:
  US09/596,229
• Time in Patent Office: 985 Days
• Field of Search: 156/322, 156/94, 156/309.6, 156/309.9, 156/306.6, 156/73.5, 156/244.17, 156/244.11, 156/569, 156/304.1, 156/304.2, 156/304.4, 156/304.5, 156/304.6, 108/57.25, 108/57.34, 108/51.11, 108/901, 108/902, 108/57.17, 108/51.17
• US Class Current: 156/309.6
• CPC Class Codes: B29C 65/203 being several single mirrors, e.g. not mounted on the same tool
• CPC Class Codes: B29C 65/2061 by sliding
• CPC Class Codes: B29C 65/2076 perpendicularly to the plane comprising the parts to be joined
• CPC Class Codes: B29C 65/305 involving the use of cartridge heaters
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/114 Single butt joints
• CPC Class Codes: B29C 66/4326 for making hollow articles or hollow-preforms, e.g. half-shells
• CPC Class Codes: B29C 66/52431 with a right angle, e.g. for making L-shaped pieces
• CPC Class Codes: B29C 66/5244 for forming fork-shaped connections, e.g. for making window frames or Y-shaped pieces
• CPC Class Codes: B29C 66/5268 characterised by their solid cross sections being non-circular, e.g. being elliptical, square or rectangular
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/8122 characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
• CPC Class Codes: B29C 66/818 characterised by the cooling constructional aspects, or by the thermal or electrical insulating or conducting constructional aspects of the welding jaws or of the clamps characterised by the heating means B29C65/24; comprising means for compensating for the thermal expansion of the welding jaws or of the clamps
• CPC Class Codes: B29C 66/8242 Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/91212 involving measurement means being part of the welding jaws, e.g. integrated in the welding jaws
• CPC Class Codes: B29C 66/91231 of the joining tool
• CPC Class Codes: B29C 66/91421 of the joining tools
• CPC Class Codes: B29K 2023/065 HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2827/18 PTFE, i.e. polytetrafluorethene, e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2909/02 : Ceramics
• CPC Class Codes: B29L 2031/7178 : Pallets
• CPC Class Codes: B65D 19/0095 : and each contact surface having a stringer-like shape
• CPC Class Codes: B65D 2519/00034 : Plastic
• CPC Class Codes: B65D 2519/00069 : Plastic
• CPC Class Codes: B65D 2519/00104 : Plastic
• CPC Class Codes: B65D 2519/00278 : the load supporting surface and the base surface being identical
• CPC Class Codes: B65D 2519/00293 : made of more than one piece
• CPC Class Codes: B65D 2519/00323 : made of more than one piece
• CPC Class Codes: B65D 2519/00333 : contact surface having a stringer-like shape
• CPC Class Codes: B65D 2519/00373 : whereby at least one spacer is made of one piece
• CPC Class Codes: B65D 2519/00557 : without separate auxiliary elements
• CPC Class Codes: B65D 2519/00562 : chemical connection, e.g. glued, welded, sealed
• CPC Class Codes: Y10S 108/901 : Synthetic plastic industrial platform, e.g. pallet
• CPC Class Codes: Y10S 108/902 : Made with deformable integral fastening elements

Abstract

A plastic pallet assembly is formed from plastic lumber by melting sections of runners and cross members and contacting them to join said runners and said cross members to form a pallet. A machine having an assembly table, cross members for supporting and moving pallet runners in a vertical direction, a support table for a pallet cross member, hot plates moveable in a vertical direction and in a horizontal direction for insertion between the runners and the cross member, and a force bar moveable in a vertical direction for applying a force to the runners, hot plates and cross member. A process for producing a plastic lumber pallet in which the runners are placed on a support bar and raised in a vertical direction, a cross member is placed on a support table, hot plates are inserted between the runners and cross member, pressure is applied by means of a force bar and a portion of the runners and cross member is melted after which the hot plate is withdrawn by raising the runners and hot plate and the molten section of the runners and cross member are brought in contact to join the runners and cross member.

Claims

1. A process for welding a plastic lumber runner to a plastic lumber cross-member used in forming a plastic lumber pallet comprising:

a. loading a solid, plastic-lumber runner on a runner support member;

b. placing a solid, plastic-lumber cross-member on a cross-member support;

c. separating said runner from said cross-member so as to produce a gap between said runner and said cross member;

d. inserting a hot plate in said gap between said runner and said cross member;

e. contacting said runner with a first side of said hot plate and simultaneously contacting said cross member with a second, opposite side of said hot plate;

f. heating said hot plate to a temperature sufficient to form a molten portion of at least one of said cross member and said runner;

g. separating said runner from said hot plate to form a space between said hot plate and said runner;

h. separating said hot plate from said cross-member;

i. withdrawing said hot plate;

j. contacting said cross member substantially transversely with said runner in the region of said molten portion to form a weld between said cross member and said runner of said plastic-lumber pallet in which said cross-member and said runner are positioned one on top of the other.

2. The process for welding a plastic lumber runner to a plastic lumber cross-member according to claim 1 wherein said heating step forms a molten portion on both said cross member and said runner.

3. The process for welding a plastic lumber runner to a plastic lumber cross-member according to claim 1 further comprising the step of applying a force to said runner, said hot plate, and said cross-member during said heating step sufficient for excess melted plastic to come out from around said hot plate.

4. The process for welding a plastic lumber runner to a plastic lumber cross-member according to claim 1 further comprising the step of applying a force to said runner and said cross-member during said contacting step of said cross member and said runner to form a weld between said runner and said cross-member and sufficient to form a flash bead of said molten plastic around said weld.