Jervis B. Webb Company

George D MacMunn

Clarence A Dehne

Shelden M Kavieff

Ward T Brennan

A reciprocatable shuttle employed to advance a variable number of article carriers through successive work stations is driven on forward and return movements by a plurality of energizable linear motor stators for which the shuttle forms a common reactor. Energization of the stators is controlled by a programmable logic contoller in response to inputs from velocity measuring circuits which determine the difference in the actual velocity of the shuttle relative to a desired maximum forward velocity, return velocity and creep velocity; to inputs from distance measuring curcuits which determine the distance travelled by the shuttle relative to a forward deceleration point and to a return deceleration point; to inputs which establish the return or forward position of the shuttle; and, to inputs which count the number of article carriers to be advanced. The programmable logic causes the stators to be progressively energized at timed intervals in response to a velocity ON signal to accelerate the shuttle to that velocity; to maintain the shuttle at that velocity; and, in response to a distance signal, to reversely energize the stators until the shuttle reaches the creep velocity. The maximum number of stators energizable is limited in accordance with the article carrier count, and the sequence in which the stators are energized is rotated on each forward-advance movement cycle of the shuttle.

Apparatus and method for controlling linear motors

A conveyor includes carriers supported on a carrier track, pushers supported on an adjacent power track, and a work station located along the carrier track. Each carrier is propelled to a pick-up station in advance of the work station by engagement of one of the pushers with a driving dog on the carrier. A carriage, movable between the pick-up station and a discharge station following the work station and having releasable coupling devices adapted to engage carriers at the pick-up and work stations, is reciprocatably driven on forwarding and return movements by a linear motor. On the forwarding carriage movement, carriers at the pick-up and work station are rapidly advanced to the work and discharge station, respectively, and the coupling devices are released prior to the return movement of the carriage. A carrier advanced to the discharge station is re-engaged by one of the pushers of the conveyor.

Method of and apparatus for advancing conveyor carriers through a work

A block control system for wheeled, track-mounted vehicles each having a driving motor energized from power conductor rails extending parallel to the track through collector shoes mounted on the vehicle. A track layout is provided with two or more successive traffic control blocks each having a signalling section of conductor bar electrically connected to a blocking section of conductor bar in the next trailing block. The signalling and blocking conductor bar sections are engageable respectively by separate signalling and blocking contact shoes carried by each vehicle. A block control relay on each vehicle includes a contact in series with the vehicle driving motor control circuit, and the operational state of this relay is controlled by a circuit which is established through the signalling and blocking contact shoes and the conductor bar sections engaged thereby and which applies a blocking signal to the relay of a vehicle in a trailing block in response to the presence of a vehicle in a leading block. Alternative constructions are disclosed for stopping the vehicle in response to energization or to de-energization of the relay, and for controlling the relay by trackside-mounted circuits.

Block control system for self-propelled vehicles

A system for providing a buffer between upstream and downstream article processing lines employs a storage and retrieval machine operable in a storage mode to store in a matrix of storage bins unit loads of articles received from the upstream line during an interruption in the processing rate of the downstream line; and, operable in a retrieval mode to supply the stored articles to the downstream line when required. The storage machine includes separately driven components consisting of a horizontally movable carriage, a vertically movable elevator mounted on the carriage, and a bi-laterally movable load carrying table mounted on the elevator. Movements of these components are regulated by a control which counts the number of unit loads in storage and computes, in accordance with predetermined storage and retrieval sequences, the location in the matrix of the storage bin for the next storage or retrieval operation and directs the machine table to that location. In the storage mode, each successive storage operation of the machine is initiated in response to the presence of a group of articles, or unit load, at a transfer station located adjacent the entrance to the downstream line; and, in the retrieval mode, each successive operation of the machine occurs in response to the deposit of a unit load on the transfer station by the table of the machine.

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Southfield, MI, United States of America

George D MacMunn