Improvements in Measuring Rules for the use of Miners Surveyors, Builders and the like

摘要

26,938. Richards, J. Dec. 11. Levelling-staves.-In a measuring-rule for the use of miners, surveyors, builders, &c., two or more members a, a', capable of sliding upon one another longitudinally, are secured together by tie-plates b, b1, and the member a1 is provided with a feather c engaging a corresponding groove c1 formed in the member a. In order to prevent separation of the members by over-sliding when being returned to their closed position, the groove c1 terminates a short distance from the top of the member a, the extremity of the groove being protected by a small metal plate, while the feather c terminates a short distance from the top of the member a'. The members a, a1 are clamped in any required position by means of a set-screw e, which passes through the tie-plate b1 and through a metallic boss in the member a, its point entering the groove c'. A suitable scale may be marked upon the member a.