| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent short-circuit caused by contact of an electric heating wire. SOLUTION: A through hole 14 is provided in the approximately central part of a synthetic resin sheet 13, a spiral groove 15 around the through hole 14 is carved on one surface of the sheet 13, a heating die is pressed to the suitable part of the front surface of the sheet after inserting an electric heating wire 2 along the spiral groove 15, and an opening of the spiral groove 15 is partially blocked with molten resin. When a straight line extending along the front surface of the sheet 13 and passing the center of the through hole 14 is taken as a reference line X, more than three winds on the outermost peripheral side of the spiral groove 15 is crushed by the heating die over the width of 1/60 to 1/15 of the length of the circumference of the spiral groove 15, on the straight line with the through hole 14 as the center and inclined at 45 deg. in relation to the reference line X, and molten resin is filled in the spiral groove 15 to fix the electric heating wire 2.</p> |
