| 摘要 |
The invention comprises a grille blade, a frictional blade assembly for grilles using blades, and a grille assembly using blades, each blade defining a first and second end and upper and lower sides, being of uniform cross-sectional shape and size along its length, each blade defining a generally streamline-shaped tube, the tube defining a first edge, a second edge and an internal space and being formed from an integral sheet of relatively thin material, whereby the sheet is bent back upon itself and one sheet edge is secured below another, the internal space at the first edge being of generally circular cross-section over an arc of approximately 270 DEG , a circular cross-section having a diameter of between 0.002'' and 0.004'' less than that of abutments over which the blades are to be rotatably attached.
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