Improvements in Flexible Rulers

7951. Dunn, E. A. A. April 6. Rulers.-Flexible rulers are made of sheet metal with a double row of circular or oval projections b, c, Fig. 2, stamped on one or both sides, parallel to the ruling edges, to prevent them from slipping. These projections may be perforated at their lower ends, as in Fig. 5, which shows a section of a ruler as applied to a curved surface. The projections may also be formed by transverse corrugations or flutings, or by cutting slits in the blank and turning down the parts cut out, as shown in Fig. 9. Two downwardly-projecting parts may be inclined to each other so as to meet, as at f, Fig. 12, and form a strong rib. The projections may be filled with india-rubber &c., a head being left to receive the fingers, and their edges may be marked with a variety of scales, whereby the distances between the lines drawn may be regulated and varied.