Patent for a new and improved trace-carrier. This design "consist[s] of a rectangular frame, a central integral transverse bar provided at its upper and lower edges with pairs of spaced-apart superficial ribs having central aligning bores, a spring-pressed bolt mounted in one of said ribs, adapted at its inner end to take into the opposite rib and provided at its outer end with a knob or head, a pintle mounted in the lower pair of ribs, a tongue pivoted upon the pintle, said tongue having its upper end reduced to fit between the upper pair of ribs and provided with an eye for the reception of the bolt" (lines 82-94).