Welded item

• US 7,005,025 B2
• Filed: 06/20/2003
• Issued: 02/28/2006
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• Current Assignee: TBDC LLC
• Original Assignee: TBDC LLC
• Inventors: Summers, Wade
• Primary Examiner(s): Haran, John T.
• Application Number:
  US10/600,204
• Publication Number:
  US 20050247395A1
• Time in Patent Office: 984 Days
• Field of Search: 156/156, 156/242, 156/244.17, 156/244.22, 156/245, 156/272.2, 156/273.7, 156/275.1, 156/292, 156/308.2, 156/308.4, 156/309.6, 425/174, 425/408, 425/395, 425/233, 264/449, 264/491, 264/523, 264/524, 264/319, 264/325, 264/326, 473/609, 473/610, 473/611
• US Class Current: 156/156
• CPC Class Codes: B29C 2035/0861 using radio frequency
• CPC Class Codes: B29C 2793/009 after shaping
• CPC Class Codes: B29C 49/0691 using sheet like material, e.g. sheet blow-moulding from joined sheets
• CPC Class Codes: B29C 49/20 of articles having inserts or reinforcements ; Handling of inserts or reinforcements
• CPC Class Codes: B29C 49/60 Blow-needles
• 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 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/04 Dielectric heating, e.g. high-frequency welding , i.e. radio frequency welding of plastic materials having dielectric properties, e.g. PVC
• CPC Class Codes: B29C 66/004 Preventing sticking together, e.g. of some areas of the parts to be joined
• CPC Class Codes: B29C 66/137 Beaded-edge joints or bead seals for sealing or securing package folds or closures B65B51/24
• CPC Class Codes: B29C 66/326 Shaping the burr, e.g. by the joining tool
• CPC Class Codes: B29C 66/3282 for reinforcing the joint
• CPC Class Codes: B29C 66/54 Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
• 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 66/72341 for gases
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2101/12 Thermoplastic materials
• CPC Class Codes: B29K 2995/0067 non-permeable
• CPC Class Codes: B29L 2022/02 Inflatable articles balls B29L2031/54 ; inner tyres B29L2023/245
• CPC Class Codes: B29L 2023/245 : Inner tubes
• CPC Class Codes: B29L 2031/54 : Balls
• CPC Class Codes: B29L 2031/7506 : Valves
• CPC Class Codes: B60C 17/06 : resilient
• CPC Class Codes: B60C 17/066 : made-up of plural spherical elements provided in the tyre chamber
• CPC Class Codes: Y10T 428/1352 : Polymer or resin containing [i.e., natural or synthetic]

Abstract

A welded item is shown having an extruded weld bead with a high tensile strength relative to the layers from which it is formed. A valve with an insert is shown. A ball with an internal plenum is shown.

Claims

1. A method for welding together two layers of thermoplastic material, comprising the steps of:

providing first and second opposed dies, each of said dies having a flat portion and defining a recess adjacent to said flat portion;

placing at least two substantially flat layers of thermoplastic material between said first and second opposed dies, with the flat portions of the dies opposite each other and the recessed portions of the dies opposite each other;

applying energy to said dies to melt the thermoplastic material between said dies;

pressing said dies together to compress and reduce the thickness of the material between the flat portions of the dies at least 70%, thereby extruding some of the thermoplastic material into the recesses of said dies; and

producing a weld that is at least 50% as strong as one of the layers of the thermoplastic material.

2. A method for welding together two layers of thermoplastic material as recited in claim 1, wherein said heating is achieved by applying radio frequency electrical energy to the dies, and wherein the opposed recesses in the first and second opposed dies are mirror images of each other.

3. A method for welding together two layers of thermoplastic material as recited in claim 1, and further comprising the step of causing the layers on the recessed side of the dies to be held apart from each other throughout during the extruding process.

4. A method for welding together two layers of thermoplastic material as recited in claim 3, wherein said flat surfaces and said recesses define the perimeter of an inflatable welded item;

and

wherein the layers are held apart by inflating the item.

5. A method for welding together two layers of thermoplastic material as recited in claim 1, wherein there is a projection from one of the dies that lies adjacent to the flat surface of its respective die and projects toward the other of the dies beyond a plane formed by the flat surface of its respective die and further damming the side of said flat portions opposite said recesses by using said projection in order to direct extruded material toward said recesses.

6. A method for welding together two layers of thermoplastic material as recited in claim 4, and further damming the side of said flat portions opposite said recesses in order to direct extruded material toward said recesses.

10. A method as recited in claim 4, wherein each of said dies also has a steeply tapered wall adjacent its respective recess, and including the step of pressing said layers against their respective steeply tapered walls while the energy is being applied.

7. A method for welding together layers of thermoplastic material of uniform thickness to form an airtight, inflatable product, comprising the steps of:

providing first and second opposed dies including opposed flat surfaces and opposed recesses adjacent to said opposed flat surfaces, so as to define the perimeter of the inflatable product;

placing the substantially flat layers of thermoplastic material between said opposed dies;

applying energy to melt the thermoplastic material between the opposed flat surfaces;

injecting gas between said layers in order to hold the layers apart from each other within said perimeter; and

pressing said dies together to reduce the thickness of the thermoplastic material between the flat surfaces at least 60% in order to extrude some of the melted material into the recesses.

8. A method as recited in claim 7, wherein there is a valve extending through one of said layers, and the step of injecting gas includes injecting gas through said valve.

9. A method as recited in claim 7, wherein said step of injecting gas occurs before the step of applying energy to melt the thermoplastic material, and wherein said gas pushes said extruded melted material against the recesses.