Frame assembly jig

Claim 1

A frame assembly jig to provide automatically aligned and compressed assembly of mitered frame members, the assembly jig comprising: a sheet metal angle member comprising: first and second frame-positioning parts forming an angle therebetween to receive abutting ends of first and second frame members, and first and second binder guides on the first and second frame-positioning parts, respectively; a flexible binder threaded through openings in the binder guides, the binder being long enough to encircle the perimeter of a loose assembly of the frame members to hold the members in assembled loop position; a main support comprising: a first sheet metal member bent into a U-shaped configuration comprising first and second straight, parallel rails and a first bridge integrally joined to one end of each of the rails, the other end of the rails being rigidly attached to the angle member, a second bridge rigidly attached to the other end of the rails, and apertures in the first and second bridges aligned along an axis parallel to the rails; a draw bar comprising: a plate comprising first and second notches in one side spaced apart corresponding to the spacing between the rails and slidably fitting over the rails, a threaded aperture located in a central region of the draw bar between the notches, and attachment means to receive the binder, the attachment means being located outwardly with respect to the notches and substantially in line with the threaded aperture, end portions of the binder being attached to the draw bar at the attachment means with sufficient slack between the end portions to encircle the loose assembly of the frame members; a threaded rod journaled in the apertures in the first and second bridges extending parallel to the first and second rails, the threaded aperture of the draw bar being threaded onto the rod, the binder being attached to the draw bar attachment means, one end of the rod bearing against the angle member, whereby rotation of the rod presses the rod against the angle member and moves the draw bar longitudinally along the rails to exert tension in the binder, the tension being divided along both the first and second frame members to draw all of the frame members into aligned and compressed assembly.