| 摘要 |
A grading screen is formed from one or more sheets (10) of wear-resistant, non-metallic, material in which a plurality of closely spaced apertures (12) are provided. One elongate sheet (10) is formed into a continuous belt with its ends joined together by fastening means. The fastening means comprises two parts (30, 32). Both parts (30, 32) are of reflexive section and having two limbs (34) with one part (30) being secured to each end of the sheet (10) with a limb (34) above and below the said end of the sheet (10). One part (30) is provided with a lengthwise series of hook elements (36) and the other part (32) is provided with a correspondingly spaced lengthwise series of apertures (38) through which extends and is secured a rod (40) around which each hook element (36) is engageable and is held. |
