초록 ▼

An improved method of hollow metal screen frame production allows screen frames to be produced far more quickly than has heretofore been possible. Each of the cutting dies in the production line is provided with an accelerator that moves the prenotching dies at the speed of the flat sheet metal stri

An improved method of hollow metal screen frame production allows screen frames to be produced far more quickly than has heretofore been possible. Each of the cutting dies in the production line is provided with an accelerator that moves the prenotching dies at the speed of the flat sheet metal strip used to form the screen frames. As a consequence, the sheet metal strip can be fed continuously without stopping for punching of corner openings. Also, the configuration of the corners are improved by die cutting locking tabs and corresponding locking tab openings in adjacent members. Once the screen frame has been longitudinally bent at its corners to form the jamb, head, and sill members, the locking tabs of one member project through locking tab openings defined in an adjacent member. The locking tabs are simultaneously bent over using forming dies arranged in pairs with the forming dies within each pair acting in opposition to each other. The forming dies thereby concurrently, inelastically deform the locking tabs so that they cannot be withdrawn through the locking tab openings. The corners of the frame are thereby held in right angle alignment.

대표청구항 ▼

A method of forming a hollow metal screen frame comprising the steps of: (a) cutting an elongated, flat sheet metal strip; (b) continuously feeding said flat sheet metal strip on a conveyor moving continuously at a predetermined speed and in a predetermined direction while providing support to said

A method of forming a hollow metal screen frame comprising the steps of: (a) cutting an elongated, flat sheet metal strip; (b) continuously feeding said flat sheet metal strip on a conveyor moving continuously at a predetermined speed and in a predetermined direction while providing support to said flat sheet metal strip from beneath; (c) mounting a cutting die at a predetermined location above said conveyor, said cutting die being operable for actuation to strike said flat sheet metal strip and thereby punch openings therein, and for deactuation to withdrawl said cutting die from contact with said metal strip; (d) actuating said cutting die while concurrently advancing said cutting die from said predetermined location in said predetermined direction and at said predetermined speed; (e) deactuating said cutting die while concurrently retracting it to said predetermined location; (f) cutting said strip into separate sections, each section being of a length equal to the perimeter of a single frame; (g) rolling each of said sections to form an essentially rectangular frame stock; (h) crimping said longitudinal edges of each section together between said openings to from a pair of jamb members and a pair of members transverse thereto including a head member and a sill member in which said members of each pair alternate with the members of each other pair; (i) longitudinally bending each section at said openings therein to bring said jamb members into perpendicular alignment relative to said head and sill members to form corners; and (j) joining each member of a section to each adjacent member thereof at all of said corners.