| 摘要 |
1442073 Excavator teeth WESTERN ROCK BIT CO Ltd 28 May 1974 [29 May 1973] 23512/74 Heading E1F The transverse concavity of the upper surface and the transverse convexity of the lower surface of the digging portion of a digger tooth are such that the outer side edges of the digging portion are thicker than the central region of said portion so that, during use of the tooth, the tooth wears to enable the front ends of the side edges to precut a portion of material on each side of the material being freed by the central portion of the front digging edge of the tooth. Preferably the side edges are parallel and the profile of the lower surface varies relative to the constant profile of the upper surface so that lengthwise of the digging portion the thickness of the central portions of lateral sections of the digging portion of the tooth increase at a rate approximately 2.5 times the thickness of the leading central edge of the tooth per inch of length of the digging portion of the tooth. U.S. Specification 3665623 and Canadian Specification 890315 are referred to. |
