| 摘要 |
<p>A U-section handrail (1) is supported by hollow rectangular bars (3) to form a metal balustrade. Slots (17) are made in a flange (16) which projects inwards from one of the two bearing surfaces, the distance between corresponding to the length of the rectangular section of the bars. The flanges has tenons (18) spaced out according to the number of bars. Two coincident slots (19) are made in the short sides (15) at the corresponding end of the bars. These form mortises into which the tenons lock when the bars are fitted into the opening underneath the handrail section. The end part of the bars buts onto the two support surfaces inside the section. The face opposite the tenons is then cut out with a special tool to form a tongue which is pressed back to 90 degrees inside the other mortise (19) flattening the tenon.</p> |
