Patent ID: 8091484

Claim:
A carriage-type conveyance system using a conveyance path formed by supporting guide rails laid on a floor surface and a conveyance carriage which travels on the supporting guide rails in a traveling direction, and is provided with an aisle crossing section where an aisle on the floor surface crosses the conveyance path, comprising: a pit formed in the floor surface of the aisle crossing section and the pit is covered by a floor member laid flush with the floor surface, elevating guide rails disposed inside the pit movably vertically parallel between a raised level at which they connect the supporting guide rails before and after the pit and a lowered level at which their upper surfaces are flush with the floor surface, elevating drive devices operable to elevate the elevating guide rails between the raised level and the lowered level, elevating apertures for the elevating guide rails formed in the floor member, the conveyance carriage having at least four guided portions at intervals in the traveling direction, conveyance carriage alignment guide rails disposed on the conveyance path before and after the aisle crossing section, and at least two of the guided portions always engaging the conveyance carriage alignment guide rails when the conveyance carriage passes through the aisle crossing section to maintain proper alignment of the conveyance carriage with the supporting guide rails as the conveyance carriage passes through the aisle crossing section, wherein in the conveyance path, a carriage stopper and a switching means are provided parallel, and where the carriage stopper is provided on at least the upstream side of the conveyance carriage traveling direction of the aisle crossing section, and is freely switched between a working posture in which the carriage stopper stops the conveyance carriage before the elevating guide rail and a nonworking posture in which it allows the conveyance carriage to pass through, and the switching means switches the carriage stopper into the working posture only when the elevating guide rail is at the lowered level in conjunction with the vertical movements of the elevating guide rail.