Stone metering system for railroad track maintenance vehicle

A railroad track maintenance vehicle comprising:

• a superstructure adapted to travel along a railroad track;
• at least one workhead carried on said superstructure;
• a plurality of blow tubes carried on said workhead;
• a main hopper carried on said superstructure;
• a supply of ballast stones carried in said main hopper;
• and
• a means for moving the ballast stones from the main hopper to the blow tubes including a stone replenishing system, a stone metering apparatus, and a splitter means for dividing and distributing stone exiting said stone metering apparatus to said blow tubes;
• said stone metering apparatus including:
• a casing defining an inlet and an outlet through which said ballast stone is received and discharged, respectively, said casing having a uniform diameter between said inlet and said outlet;
• and
• a screw rotatably supported within said casing for conveying said ballast stone from said inlet to said outlet, said screw having an outlet end proximate said outlet, said screw having a remainder other than said outlet end, said screw having a non-uniform diameter along its length, said diameter of said outlet end of said screw being less than said diameter of said remainder of said screw, whereby said ballast stones flow together at said outlet end to reduce bunching and provide relatively even flow from said casing outlet.

An improved track maintenance vehicle having a superstructure adapted to travel along a railroad track, at least one workhead carried on said superstructure, a plurality of blow tubes carried on said workhead, a supply of ballast stones carried on said superstructure, a means for moving the ballast stones from the supply of ballast stones to the workhead, wherein the improvement comprises:

• said means for moving said ballast stone from said supply of ballast stone to said workheads includes a stone metering apparatus supported upon said track maintenance vehicle and a splitter means for dividing and distributing stone exiting said stone metering apparatus to said plurality of blow tubes carried on said workhead, said stone metering apparatus comprising a stone metering auger including a casing having inlet and outlet openings and an auger screw having longitudinally opposite inlet and outlet ends rotatably housed within said casing, said casing having a uniform diameter, said auger screw including flights that increase in pitch as they extend longitudinally along the screw away from said inlet end, said auger screw further including flights that decrease in diameter at said outlet end, whereby said increasing pitch reduces production of fines within said stone metering apparatus by expanding said stone, and further whereby said decreasing diameter reduces bunching of stone by causing said stone to flow together toward said outlet end of said stone metering apparatus.

A railroad track maintenance vehicle, comprising:

• a superstructure adapted to travel along a railroad track;
• at least one workhead carded on said superstructure;
• a plurality of blow tubes carded on said workhead;
• a main hopper carded on said superstructure;
• a supply of ballast stones carded in said main hopper;
• and
• a means for moving the ballast stones from the main hopper to the blow tubes including a stone replenishing system, a stone metering apparatus, and a splitter means for dividing and distributing stone exiting said stone metering apparatus to said blow tubes;
• said stone metering apparatus including a stone metering auger supported upon said superstructure, said stone metering auger having a casing with inlet and outlet openings and an auger screw with longitudinally opposite inlet and outlet ends rotatably housed within said casing, said casing having a uniform diameter, said auger screw including flights that decrease in diameter at said outlet end of said auger screw and increase in pitch as they extend along the length of said screw away from said inlet end toward said outlet end, whereby said increasing pitch reduces production of fines within said stone metering apparatus by expanding said stone, and further whereby said decreasing diameter reduces bunching of stone exiting said stone metering apparatus by causing said stone to flow together toward said outlet end.