Apparatus for making envelopes from a continuous film sheet

Claim 1

Apparatus for making envelopes from a continuous film sheet comprising: means for supporting a film roll with its axis being substantially horizontally and kept so as to unwind therefrom as a continuous film sheet having a width extending in a horizontal direction, means for changing the direction of extension of said width of the film sheet continuously unwound from said film roll so as to have said width in a vertical direction, said direction changing means comprising a vertically disposed slant plate having a slanting guide edge engaging said film sheet for changing the course of movement of the film sheet, and thereby the direction of extension of said width of the film sheet, means for slitting the film sheet having its width extending in a vertical direction along its center line into two continuous strips, means for adjusting the position of said slant plate in a vertical direction to maintain the center line of the film sheet having its width extending in a vertical direction aligned with said slitting means, means for changing the forwarding directions of said two continuous strips so as to be superposed on each other with their planes of extension being substantially horizontally kept, means for heat-sealing said superposed strips in lengthwise and transverse directions to form a plurality of rectangular sections defined by heat-sealed sides, and means for slitting and cutting the heat-sealed sheet into separated envelopes having their respective three heat-sealed edges.