Abstract: A foldable ruler includes a first ruler segment, a second ruler segment pivotally coupled to the first ruler segment, a third ruler segment pivotally coupled to the second ruler segment, and a fourth ruler segment pivotally coupled to the third ruler segment. Each of the first, second, third, and fourth ruler segments includes a first side surface and a second side surface opposite the first side surface. At least one of the first and second side surfaces includes a first set of indicia representing units of measurement. Each of the first, second, third, and fourth ruler segments also includes a top surface extending between the first and second side surfaces. The top surface of the fourth ruler segment includes a second set of indicia representing a plurality of angles.

Abstract: A drawing instrument including two rulers each having a head portion, a circular protrusion formed on one of the head portions, and a circular recess formed in the other head portion for slidable engagement with the circular protrusion, the rulers are guided to rotate relative to each other by the slidable engagement between the circular protrusion and the circular recess. The head portions can be easily coupled together without additional tools or without additional coupling devices.

Abstract: An elongated body is provided including opposite side portions removably secured together by transverse threaded fasteners. One set of corresponding ends of the side portions include relieved areas opening toward each other defining a cavity opening outwardly of the corresponding end of the body and along one longitudinal edge thereof. A protractor arm is pivotally mounted within the notch for movement between a retracted position received within the cavity and extending along the one edge and an extended position disposed at substantially 90.degree. relative to the elongated body. The body and protractor arm include coacting structure for adjustably limiting angular displacement of the protractor arm to the extended position and the ends of the opposite side portions of the body remote from the protractor arm include two pairs of opposing sockets formed therein in which spirit level supporting annular bodies are mounted.

Abstract: A multifunction, multipurpose construction tool comprised generally of two operating arms pivotally connected via their terminal ends, preferably their rounded terminal ends, one to the other, an angle indicator being provided at the pivotal connection, or hub, for reading the angle formed by the two arms. A pair of alternately disposed abuttments are located at the extremities defining the rounded end of one of said arms as well as the beginning and end of the scale of angular component values of the scale. A stop located on the rounded terminal end of the other pivotally connected arm provides a means for indexing the scale of angular values between said alternately disposed abuttments.