초록 ▼

A method and apparatus is provided for securing together overlapping portions of a thermoplastic strap loop around an object. The overlapping strap portions are forced together in face-to-face contact under pressure. During or before the step of forcing the strap portions together, the energy in the

A method and apparatus is provided for securing together overlapping portions of a thermoplastic strap loop around an object. The overlapping strap portions are forced together in face-to-face contact under pressure. During or before the step of forcing the strap portions together, the energy in the strap portions is increased so as to melt at least a part of the thickness of each strap portion at the interface region. One embodiment of the method also includes forming a plurality of cavities that are distributed across the width of the molten parts adjacent the ends of the molten parts and that are surrounded by the molten parts. The step of increasing the energy is then terminated, and the strap portions at the interface region subsequently solidify, to encapsulate the cavities and form the welded joint. In another, and preferred, embodiment of the invention, the pressure on the strap portions is released while the parts of the strap portions are molten (whether or not cavities are present), and the strap portions at the interface region subsequently solidify in the absence of pressure.

대표청구항 ▼

Apparatus for producing a welded joint between two overlapping portions of thermoplastic strap, said apparatus comprising: two strap-engaging members between which said strap portions can be positioned; closing means for effecting relative movement between said two strap-engaging members to engage s

Apparatus for producing a welded joint between two overlapping portions of thermoplastic strap, said apparatus comprising: two strap-engaging members between which said strap portions can be positioned; closing means for effecting relative movement between said two strap-engaging members to engage said strap portions and force said strap portions into face-to-face contact under pressure at an interface region; member moving means for moving one of said strap-engaging members while in contact with one of said strap portions to effect relative bodily sliding movement between said strap portions whereby at least part of the thickness of each strap portion melts at said interface region; and opening means for effecting relative movement between said two strap-engaging members to release said pressure on said strap portions and to effect disengagement between at least said one strap-engaging member and said one strap portion while said parts of said strap portions are molten whereby said strap portions at said interface region subsequently solidify in the absence of pressure from said strap-engaging members to form said welded joint. A method for producing a welded joint between two overlapping portions of thermoplastic strap, said method comprising the steps of: (A) positioning said overlapping strap portions between two strap-engaging members; (B) effecting relative movement between said two strap-engaging members to engage said strap portions and force said strap portions into face-to-face contact under pressure at an interface region; (C) increasing the temperature of said strap portions at said interface region sufficiently to melt at least part of the thickness of each strap portion at said interface region; and (D) effecting relative movement between said two strap-engaging members to release said pressure on said strap portions while said parts of said strap portions are molten whereby said strap portions at said interface region subsequently solidify in the absence of pressure from said strap-engaging members to form said welded joint.