Patent ID: 8365363

Claim:
A strap fastening device for connecting to two opposite lateral ends of an object, comprising: two elastic fastening straps, each of which having a fixing end and an opposing free end; the fastening straps being pivotally connected at the fixing ends to the two opposite lateral ends of the object; and a tightness adjusting unit including: an assembling box being correspondingly provided on a left and a right half with at least one non-return retaining tooth each; and two slidable locating members being separately slidably mounted on the assembling box and connected to the free ends of the two fastening straps; the two slidable locating members each being provided at a predetermined position with a raised locating rib for correspondingly releasably engaging with the non-return retaining teeth on the left and the right half of the assembling box, wherein the assembling box includes a box body and a cover plate closed to each other; the box body being provided on a front face with two spaced and lengthwise extended elongated slots arranged side by side on a left and a right half of the box body, the non-return retaining teeth being separately located on an inner side of the front face above and below each of the two elongated slots, and the non-return retaining teeth located on the left and the right half of the box body being inclined in the same angle toward a central area between the left and the right half; and two opposite lateral ends of the box body being formed into two open entrances; the cover plate being closed onto a rear side of the box body opposite to the front face with the two elongated slots to thereby define a receiving space between the cover plate and the box body; and wherein the two slidable locating members each include a substantially U-shaped base plate and an operating plate; the U-shaped base plates providing a certain degree of elasticity and being received in the receiving space of the assembling box, and the raised locating ribs being provided on an outer surface of the U-shaped base plates facing toward the non-return retaining teeth; and the operating plates being separately perpendicularly extended from an end of the U-shaped base plates to outward project from the two elongated slots; and the free ends of the two fastening straps being separately extended through the two open entrances of the box body into the receiving space to connect to the two slidable locating members.