High load overhead conveyor drive system

An overhead conveyor system, for transporting at least one load along a conveying path that has at least a primary horizontal component, comprising:

• a stationary frame extending along the conveying path;
• a drive motor mounted to said frame and having a rotational power output;
• a mechanical transmission having a power input connected to said rotational power output of said drive motor and further having a rotational power output;
• a drive shaft extending along the conveying path and mounting to said frame for rotation about a shaft axis that is parallel to the conveying path;
• a power connection between said rotational power output of said mechanical transmission and said drive shaft for rotatably driving said drive shaft about said shaft axis;
• a carriage having a first part for driving said carriage and a second part for carrying the load;
• a support surface fixed with respect to said frame and extending along the conveying path;
• a support roller normally spaced above said support surface by a fixed distance when there is no load and being rotatably mounted on said second part of said carriage about an axis transverse to said shaft axis;
• at least one driven element mounted on said first part of said carriage, and said driven element and said drive shaft engaging with sufficient traction so as to form a helical loci of engagement about the periphery of said drive shaft during rotation of said drive shaft about said shaft axis to power said carriage along the conveying path in a direction of the conveying path dependent upon a direction of rotation of said drive shaft;
• said carriage first part and second part being drivingly connected to each other in the direction of the conveying path and providing a lost motion connection between each other in a vertical direction;
• a bias mechanism biasing said first part and said second part vertically away from each other throughout a range of said lost motion connection for providing sufficient engagement traction force between said driven element and said drive shaft to power the carriage along the conveying path;
• and
• said fixed distance being less than or substantially equal to said range of said lost motion connection so that as the load increases from the no load, said range of lost motion connection decreases and said support roller approaches said support surface until said support roller engages said support surface at a fixed load weight to thereby limit a portion of load weight carried by said drive shaft to said fixed load weight even when the load exceeds the fixed load weight.

A conveyor system for carrying a load along a conveying path, comprising the following elements:

• a load support structure extending along the conveying path;
• a drive motor having a rotational power output;
• a cylindrical drive shaft extending along the conveying path, mounting for rotation about a shaft axis, and drivingly connecting to said drive motor;
• a first carriage portion and a second carriage portion, drivingly interconnected in a direction of the conveying path and providing a lost motion connection therebetween perpendicular to the conveying path;
• and
• a bias mechanism mounted between said first carriage portion and said second carriage portion biasing said first carriage portion and said second carriage portion in one bias direction relative to each other throughout a range of said lost motion connection;
• a plurality of driven wheels rotatably mounted about a plurality of driven wheel axes on said first carriage portion, with said driven wheel axes being non-parallel to said drive shaft axis and each other, and said driven wheels engaging said drive shaft at positions spaced from each other about a top periphery of said drive shaft so that rotation of said drive shaft about said shaft axis will power said first carriage portion and thereby said second carriage portion along the conveying path in a direction dependent upon direction of rotation of said drive shaft to define a helical loci of engagement about the periphery of said drive shaft;
• said second carriage portion having a support wheel vertically spaced above said load support structure by a substantial amount less than or substantially equal to and parallel to said range of lost motion;
• said second carriage portion supporting a weight of the load;
• and
• said elements being so positioned, arranged and constructed that a first portion of weight of the load is carried by said second carriage portion through said bias mechanism, through said first carriage portion, through said plurality of driven wheels and to said drive shaft, and thereafter a next portion of weight of the load is carried by said second carriage portion through said support wheel to said load support structure independently of said first carriage portion, said driven wheels and said drive shaft.