Sheet material pin feed tractor mechanism

A tractor mechanism for advancing sheet material having spaced apertures therealong;

• said mechanism comprising:
• a. a supporting frame;
• b. a drive sprocket;
• a drive shaft on which said sprocket is mounted and which rotates said sprocket;
• said shaft being supported on said frame, thereby supporting said sprocket with respect to said frame;
• said drive shaft being profiled around its exterior for engaging a clamping means;
• c. clamping means for embracing said drive shaft and comprising a plurality of separate clamping pieces, each shaped to have a profiled surface portion that conforms to a respective part of said profiled exterior of said drive shaft;
• each said clamping piece embracing said drive shaft in registry with its respective said portion of said exterior of said drive shaft with which its said profiled surface portion conforms;
• d. means adjustably securing said clamping pieces to said sprocket whereby said drive shaft rotates said sprocket without play;
• e. idler means spaced from said sprocket;
• means on said frame for supporting said idler means;
• said idler means having a substantially U-shaped peripheral edge;
• the curved end of said idler means being remote from said sprocket, the peripheries of said sprocket and of said idler means collectively defining an oval shaped guide path for a continuous belt means;
• f. closed loop belt means entrained about said sprocket and said idler means;
• g. a plurality of pins projecting outwardly from said belt for engaging the perforations in sheet material;
• h. sprocket engaging elements on said belt;
• said sprocket periphery having a plurality of spaced grooves whereby rotation of said sprocket advances said elements and said belt.

A tractor mechanism for advancing sheet material having spaced apertures therealong;

• said mechanism comprising:
• a. a supporting frame;
• b. a drive sprocket;
• a drive shaft on which said sprocket is mounted and which rotates said sprocket;
• said shaft being supported on said frame, thereby supporting said sprocket with respect to said frame;
• c. idler means positioned adjacent said sprocket;
• means on said frame for supporting said idler means;
• said idler means having a U-shaped peripheral edge;
• said sprocket periphery and said idler means peripheral edge cooperatively defining an oval-shaped guide path;
• d. closed loop belt means passing around said sprocket periphery and said idler means peripheral edge;
• e. sprocket engaging elements on said belt and grooves on said sprocket periphery for engaging said elements, whereby rotation of said sprocket moves said belt and said elements;
• f. each of sprocket engaging elements having a pin projecting outwardly from said belt means and towards said paper document and being oriented so as to selectively engage the perforations in sheet material;
• g. an elongated belt means support element in that said space, which is positioned to provide a supporting surface against which said belt means can be pressed as it moves past that said space;
• said belt means support element being positioned inside the enclosed pathway defined by the enclosed said belt means;
• h. a plate for engaging said pin frames and pressing said pin frames and said belt means to which said pin frames are attached against its said elongated support element, at the same time thereby squeezing said pin frames between said elongated belt means support element and said plate and preventing motion of said pins toward and away from said elongated belt means support element.

A tractor mechanism for advancing sheet material that has spaced apertures therealong;

• said mechanism comprising:
• a. a supporting frame;
• b. a drive sprocket;
• a drive shaft on which said sprocket is mounted and which rotates said sprocket;
• said shaft being supported on said frame, thereby supporting said sprocket with respect to said frame;
• c. U-shaped idler means spaced from said sprocket;
• means on said frame for supporting said idler means;
• said idler means having a curved end remote from said sprocket;
• said sprocket periphery and said idler means periphery cooperatively defining a guide path for a closed loop belt means;
• d. closed loop belt means passing around the peripheries of said sprocket and said idler means and being moved by said sprocket means;
• e. a plurality of pin frames secured to and arrayed along said belt means are each supporting an outwardly projecting pin for engaging a perforation in said sheet material;
• each said pin frame being individually secured on belt means;
• each said pin frame including a first upstanding flange extending along one side edge of said belt means and including a second upstanding flange extending along the opposite side edge of said belt means;
• f. said first and said second flanges having opposite ends that face toward the flange ends of neighboring pin frame flanges;
• said first and said second pin frame flanges being of a length along said belt means such that on an operative, perforation engaging portion of the path of said belt means between said sprocket and said end of said idler means, the said pin frame first flange opposite ends of one said pin frame each abut a respective said pin frame first flange end of the neighboring said pin frames, and the said pin frame second flange opposite ends of one said pin frame each abut a respective said pin frame first flange end of the neighboring said pin frames, and the said pin frame second flange opposite ends of one said pin frame each abut a respective said pin frame second flange end of the neighboring said pin frames, to thereby prevent twisting of said pin frames;
• g. a pin support arm projecting outwardly with respect to said belt means one edge and from each said first frame flange;
• an upwardly extending pin affixed on each said pin support arm;
• h. said sprocket having a plurality of grooves, said frames each having a sprocket engaging portion on said belt and adapted to be received by a groove on said sprocket periphery, whereby rotation of said sprocket causes movement of said belt and said frames.

A pin feed assembly for advancing a paper document having spaced apertures for interengagement with the pin feed assembly which comprises:

• first and second spaced parallel frames each having first and second respectively coaxially aligned openings;
• an elongated positioning rod extending through the first openings of said first and second frames;
• an elongated drive shaft arranged parallel to said positioning rod and extending through the second openings of said first and second frames;
• a drive sprocket mounted for rotation upon said drive shaft and having a collar portion extending into the second opening of said first frame, said sprocket being positioned between said first and second frames;
• a U-shaped idler positioned between said first and second frames, the curved end being remote from said sprocket and the legs of said idler extending towards said sprocket;
• said sprocket and said idler collectively defining an oval shaped contour;
• closed loop belt means entrained about said idler and said sprocket, said belt means having spaced teeth projecting towards said oval shaped path;
• pin frames being secured to said belt means and having a spanning rib with a first grooved surface engaging a tooth and an opposite curved surface;
• a pair of flanges arranged on opposite edges of said belt means and being integrally joined to opposite ends of said spanning rib;
• a strap connected to said flanges for and cooperating with said flanges and said spanning rib to embrace said belt means;
• said flanges extending downwardly from said rib towards said oval-shaped path;
• said sprocket having spaced grooves along the periphery thereof for engaging a rib and driving said belt;
• said idler having a raised track whereby said downwardly depending flanges slidably engage the periphery of said idler on opposite sides of said track to maintain said frames and said belt means in alignment as said belt means is driven;
• said first frame having a projection between said first and second openings and extending towards said second frame;
• the legs of said U-shaped idler slidably engaging said projection and being longitudinally adjustable towards or away from said second opening to adjust the tension of said belt means;
• means for securing said idler to said second frame;
• the straight peripheral portions of said idler providing support for said frames and hence said belt means;
• each of said frames having a pin tab extending away from said belt and towards said first frame;
• a pin integrally joined to and extending upwardly from said tab and away from said oval shaped path for moving into a perforation in said paper document to provide positive advancement of the document.