Patent ID: 6889816

Claim:
A device for conveying work station wagons through a plurality of working steps comprising: a) an oval track around which said work station wagons travel, said oval track comprising i) a first guide strip forming a continuous first oval, ii) a second guide strip spaced apart from said first guide strip and forming a second, larger oval, thereby forming a guide channel which is formed between said two guide strips, iii) a drive chain, comprising carrier cages, travelling inside said guide channel, and iv) said second guide strip having at least two gaps in its circumference, b) an insertion guide track located outside said second guide strip, with a portion of said insertion guide track being parallel to a portion of said second guide strip, and having a load-dependent drive in which the maximum speed is higher than the chain speed, c) a removal guide track, comprising coupling elements selected from the group consisting of switchable electromagnets, rocker heels, and switchable points tongues, located outside said second guide strip, with a portion of said removal guide track being parallel to a portion of said second guide strip, d) each of said work station wagons having i) at least one first guide roller mounted on a vertically projecting mounting provided on one side of said work station wagon, said first guide roller being removably connected to said drive chain and ii) at least one second guide roller provided on the side of said work station wagon opposite from said first guide roller, said second guide roller connecting said work station wagon to said removal guide track, and iii) a spacer that A) defines the minimum distance between said work station wagons when said work station wagons are engaged with said drive chain and B) contacts the preceding work station wagon engaged with said drive chain, with said device operating as follows: 1) said work station wagons are moved along said insertion guide track by a load-dependant friction drive to a location where said first guide roller pass through one of said gaps and engage a carrier cage on said drive chain, 2) said work station wagons are conveyed along said oval track, and 3) once said work station wagons reach another one of said gaps, said first guide roller is disengaged from the carrier cage on said drive chain and said workstation wagons are connected via said second guide roller to a coupling element on said removal guide track.