Abstract: The present invention comprises attaching a floor plate to the supporting surface or floor of a vehicle. The floor plate includes a raised horizontal portion having a plurality of elongated bayonet slots therein. A pedestal assembly adapted to support the chair includes a base plate and an upstanding pedestal member. The base plate has a plurality of bayonet members arranged to fit within the bayonet slots in the raised portion of the floor plate. Each bayonet member has a downwardly extending portion and a forwardly extending finger. To mount the device to the vehicle, the bayonet members are inserted into the bayonet slots and the base plate is moved forwardly until the downwardly projecting portions of the bayonet members engage the forward ends of the slots. The base plate is then secured against rearward movement with respect to the floor plate.