In transfer lines, a plurality of machine toots are connected together by one or more conveyor belts. The workpieces to be machined are conveyed between the machine tools on the conveyor belt on pallets, trucks or the like. These pallets have to be stopped at certain points in order to feed the workpieces, for example to a special machine tool. It is known in this connection to use stops which project in a controllable manner into the path of the pallets, The friction roller chains or other drive means are not stopped, but slide through under the pallets and thus convey other pallets which have not been stopped. As the pallets generally continue to be driven, for example, by friction roller chains, these pallets press against the stops with a certain force. In order to remove the stops from the conveying path, it is necessary to use means which generate sufficient tensile force to free the stop from the force of the conveyor acting on the stop. It is known to use hydraulic or pneumatic arrangements in this connection, controlled, for example, by an electrovalve, The use of servo means of this kind to operate the stops, in particular to remove the stops, is complicated and requires a hydraulic or pneumatic line laid at each stopping point. A control line is simultaneously required to control the stop.
The aim of the invention is to provide an arrangement which operates in the same manner as reliably as the known devices, but without using known servo means or hydraulic or pneumatic means.
USPTO Backgrounds
USPTO Backgrounds