Apparatus for wrapping articles

In an apparatus for wrapping articles in heat sealable sheet material as they move along a generally horizontal article path including a support structure, an endless-type lower jaw conveyor means having a plurality of spaced lower jaw assemblies extending crosswise of the article path, an endless-type upper jaw conveyor means having a plurality of upper jaw assemblies extending generally horizontally crosswise of the article path, the upper and lower jaw conveyor means respectively having generally horizontal lower and upper sections thereof extending forwardly along the article path in a sealing run in which one upper and one lower jaw assembly move in an opposed pair along the sealing run, lower guide means for guiding the lower jaw assemblies during movement along the sealing run, upper guide means for guiding the upper jaw assemblies during movement along the sealing run, a curtain of heat sealable material extending crosswise of the article path adjacent the inlet end of said sealing run, means for advancing an article along the article path into the curtain to draw the curtain along the top and bottom of the article and to position the article in front of an opposed pair of said jaw assemblies as they move toward the inlet end of said sealing run, each lower jaw assembly including a pair of lower clamping jaw members extending crosswise of the article path and spaced in a direction lengthwise of the article path to define a jaw opening therebetween, a generally horizontal heat sealing and cutting member extending crosswise of said article path and mounted for movement in a closed loop course extending generally tangent to said upper section of said lower jaw conveyor means in a zone intermediate the ends of said sealing run, means for driving said sealing and cutting member in timed relation with said lower jaw conveyor means along said closed loop course sequentially into the jaw opening in each lower jaw assembly as it moves past said intermediate zone to sever and seal overlapping portions of the upper and lower webs at opposite sides of the severance and then out of said lower jaw opening before the upper and lower jaw assemblies reach the end of the sealing run to allow the sealed webs to cool, the improvement wherein each upper jaw assembly includes upper jaw carrier means mounted on the upper jaw conveyor means and an upper jaw member mounted on the upper jaw carrier means for movement therewith and for limited movement relative thereto in a direction orthogonal to the path of movement of the upper jaw assembly in said sealing run, means on said upper jaw member and said upper jaw carrier means yieldably urging the upper jaw member in an upward direction relative to the associated upper jaw carrier means as the upper jaw assembly moves along said sealing run, said upper jaw guide means including:

• (a) means for guidably supporting the upper jaw carrier means during movement along the sealing run;
• (b) cam follower means on each upper jaw member;
• and (c) cam means mounted on support structure for movement relative thereto, means for moving the cam means to a first position in the path of movement of said cam follower means on upper jaw member to cam the upper jaw member downwardly relative to the upper jaw carrier means as the upper jaw assembly moves along the sealing run, said means for moving the cam means being operable to move the cam means to a second position out of the path of movement of said follower means on the upper jaw member.