| 摘要 |
An automatically recoiled tape measure with a measuring blade of concavo-convex cross-section has a recoil speed control which applies a friction retarding force directly on the blade as it approaches the termination of recoil to thereby absorb the momentum of the coiled portion of the tape prior to blade hook impact on the casing. The mouth of the casing provides a specially shaped tunnel for the blade and comprises a rigid inclined guide ramp which centers the blade and generally holds the blade out of contact with a soft elastomeric deceleration ring positioned between the ramp and the front wall of the casing. Vertical and/or horizontal to-and-fro motion of the extending portion of the blade causes the blade to frictionally contact the deceleration ring and impart a braking force thereon. Vertical flexures of the blade also causes a flattening of the blade to wedge the blade. |
