| 摘要 |
<p>PURPOSE:To enable the recognition of the fusion of a joint main body by providing, on the outer surface at a location of a heating element, a stress paint layer producing cracks equivalent to the distortion of the outer surface. CONSTITUTION:In the inner circumference of a joint main body 1, a conductive wire 3, which is a heating element consisting, for example, of a nichrome wire, is buried spirally around the axis of the joint main body 1. At a location on the joint main body 1 facing to the conductive wire 3, stress paint layers 91 and 92 of a specified width are provided to cover the entire circumference. Upon fusing of resin by heat supplied by the conductive wire 3, stress is generated within the joint main body 1, whose inner stress produces a quantity of distortion equivalent thereto on the outer surface of the joint main body 1. The distortion on the outer surface of the joint main body 1 in turn causes equivalent to the quantity of distortion in the stress paint layers 91 and 92.</p> |
