Apparatus for heat-sealing superimposed layers of sheet material

Claim 1

In an apparatus for connecting superimposed layers of sheet material, in combination, advancing means for continuously advancing a stack of superimposed sheet material layers at a predetermined speed and in a predetermined path; supply means for engaging a thread and for moving the same at least intermittently at said speed; cutting means for severing at least one predetermined length of said thread per stack from the remainder of said thread, said length having spaced end portions engaged by said supply means and sharing said movement of the latter to a position along said path adjacent one major surface of said advancing stack; pressing means for pressing said length, when in said position, intermediate said end portions thereof against said major surface with a force sufficient to disengage said end portions from said supply means, said pressing means mounted mouned for movement at said speed in a different path having a path portion extending along said predetermined path in close proximity thereof so as to press said length against said major surface during said movement of said pressing means in said path portion; stitching means spaced from said supply means and adjacent said path portion and operative for engaging said end portions of said length and for pushing the same through said stack beyond the opposite major surface thereof; and sealing means located proximal to said predetermined path in the region of said path portion at said opposite major surface and operative for deflecting said end portions into contact with said opposite major surface and for sealing the former to the latter during the advancement of said stack in said predetermined path.