Branching and joining apparatus in automatic carrying system

Claim 1

A branching and joining apparatus for use in an automatic carrying system having a main rail and at least one sub-rail each provided with a power supply line and further having an electromotive carrier adapted to run on said rails, said apparatus being disposed at a location where said main rail and said sub-rail join together, and comprising: a fixed frame; a threaded shaft extending perpendicularly to said main rail and mounted slidably in a perforation of a vertical stationary supporting plate secured to said frame; a coil spring disposed about said shaft between said supporting plate and a washer attached to one end of said shaft so that the coil spring partially covers the length of said shaft; a drive motor of reversible type having its rotor rotatably fitted on said threaded shaft; a pair of integrally movable rails fixed to said motor and each having a predetermined length; and stopper means on said fixed frame which restrict the movement of travel of said movable rails in first and second directions perpendicular to said main rail, respectively; said drive motor being adapted, when rotated in a first direction, to move along said threaded shaft together with said movable rails without compressing said coil spring until one of said stopper means is engaged by one of said movable rails to stop the movement of the motor along the threaded shaft, and thereafter to compress said coil spring so that said movable rails are locked in a straight-forward position with said coil spring substantially compressed so as to bias said movable rails against the engaged stopper means, and, on the other hand, when rotated in a second direction, to move along said threaded shaft together with said movable rails in the opposite direction without stretching said coil spring until the other of said stopper means is engaged by a different one of said movable rails to stop the movement of the motor along the threaded shaft in the opposite direction, and thereafter to stretch said coil spring so that said movable rails are locked in a branching and joining position with said coil spring substantially stretched so as to bias said movable rails against the engaged stopper means.