Tractor feed for perforated webs

A tractor feed mechanism for feeding a web in a direction length-wise thereof, said web having two rows of perforations in the length-wise direction spaced from each other width-wise of the web, said mechanism comprising a pair of endless belts with pins spaced to enter said perforations and drive elements, said pins and drive elements respectively projecting outwardly and inwardly from opposite sides of said belts, a bar having a surface providing a support platform for said drive elements and extending in a width-wise direction a distance at least equal to the width of the web, a sprocket having teeth spaced peripherally thereof between which slots for receiving said drive elements are disposed also spaced peripherally about said sprocket between said teeth thereon, said sprocket also extending in the width-wise direction, said sprocket and said bar being disposed within the insides of said belts with said drive elements received in said slots and also bearing on said support platform of said bar, a pair of web and belt guide members adjustably spaced from each other width-wise of said web and disposed on said bar, said members having slots therein extending in a direction length-wise of said web in which slots said belts are located with said drive elements on said support platform of said bar, said slots extending inwardly from surfaces of said members on which said web is disposed with said pin extending outwardly into said perforations, said surfaces of said members thereby guiding said web at a distance spaced vertically from said surface of said bar with said pins extending outwardly into said perforations, means carried by said members for locking them to said bar when positioned to provide said alignment of said pins with said rows of perforations, said members each having a lid having an inside surface, each of said lids being pivotable on its respective one of said members from an open position away from said surfaces of said members on which said web is disposed to a closed position to provide a gap between the inside surface of each of said lid and said surfaces of said members on which said web is disposed through which said web is fed, and detents on said members engagable by said lid thereon and movable against said bar into locking relationship therewith when said lid is pivoted to its closed position.