| 摘要 |
PURPOSE: To dispense with another process for blocking two corner portions of an end edge section after a bending process by forming a diamond-shaped cut-out as a closed opening separated from an outer end edge on a completed cover, and selecting the length to form a corner portion extended without crack when bending the longitudinal width of the cover. CONSTITUTION: A diamond-shaped cut-out 15 is formed on a completed telescopic cover as a closed opening separated by a continuous material portion 17' from the outer end edge 16 of an unmachined thin plate material 11' adjacently extending perpendicularly to the longitudinal direction of the cover. The width of the continuous material portion 17' in the longitudinal direction of the telescopic cover is selected in consideration of the thickness of the unmachined thin plate material 11 so as to form a corner portion 17 having a rounded contour 18 extended without generating a crack when the unmachined thin plate material 11' is bent on the continuous material portion 17'. |
