Gould Inc.

Michael C Freund

Gene J Seider

James R Duffy

An electrically powered service vehicle having a plurality of programmable electrical stations is exemplified by a food service vehicle for use with food serving trays including internal heating elements for providing localized areas of heat on the trays for maintaining food placed thereon at a desired temperature. The vehicle has a plurality of storage compartments, each of which holds a plurality of the food serving trays in vertically spaced relation to each other. An on-board d-c. power source is connected to the heating elements within the trays via a plurality of electrical contacts within each storage compartment. A d-c. drive motor for propelling the vehicle is selectively connected to the power source through a drive control. The electrical contacts within the storage compartment are positioned to engage corresponding contacts on the trays when the trays are inserted into the storage compartments. The electrical contacts within the storage compartments are part of a plurality of controllable power circuits associated with each tray station within the various compartments for supplying separately controllable power to each individual tray heater, and manually operable programming means are connected to each power circuit and generate control signals to enable or disable each separate circuit to permit the programming of the various tray stations within the storage compartments. A resilient bumper is provided on the front of the vehicle, and bumper switch means are actuated in the event the bumper contacts an external object, with the switch de-energizing the drive motor through the drive control. The d-c. power source also powers an air blower which forces air through an inlet means in the rear wall of each storage compartments and directs a stream of forced air forwardly through the storage compartment on the heated side of the tray. A door covering the front of the storage compartment forms an air outlet adjacent the side wall of the storage compartment on the heated side of the trays so that the forwardly flowing stream of forced air exits through the door.

Electrically powered service vehicle

A battery charging system for charging a battery from a conventional a.c. power source has a leakage reactance transformer connected between the power source and the battery for reducing the voltage of the power source for application to the battery. The power source is connected directly across the primary winding of the transformer to charge the battery at a high rate until it is charged to about 90% of the final capacity. A voltage sensing circuit is activated when the battery reaches about 80% of the desired final voltage, and this circuit energizes a timing motor which maintains the connection of the source directly across the primary winding of the transformer for a period of one hour, which is the normal time required for the battery charge to be increased from the 80% level to the 90% level. At the end of the 1 hour period, a cam driven by the timing motor operates a switch to connect a resistor, which is external of the transformer, in series with the primary winding of the transformer. This sharply reduces the charging current and the charging of the battery is completed at relatively low current levels which vary over a very narrow range. This 'finish' charging is continued for a 6 hour period determined by the timing motor. At the end of the 6 hour period, additional cams driven by the timing motor disconnect the power source from the transformer to terminate the charging cycle, and de-energize the timing motor. The system is automatically reset for the next charging cycle.

Battery charging system

A storage system for a plurality of food trays includes one or more storage modules each having multiple pairs of horizontal rails for supporting a plurality of trays with the hot food positioned along one side wall of the module and the cool food along the other side wall. Forced air inlet means in the rear wall and adjacent the side wall on the hot food side of the tray produces a forced air stream flowing forwardly through the module over the hot food on the trays. A door covers the front of each module and forms air outlet means adjacent the module side wall on the hot food side of the trays so that the forwardly flowing air stream exits through the door. This system is particularly suitable for use with trays which have electrical heating elements embedded in one side of the tray for heating the hot foods thereon. The electrical heaters within the trays have contacts on the bottoms of the trays at the rear ends thereof, and each tray station within the storage module has a plurality of spring contacts for engaging the tray contacts and connecting them to an on-board source. At least one of the rails in each pair has a separately projecting lug near the front of the module for engaging a complementary notch in the bottom of the tray when the tray is fully inserted into the module. Then the spring contacts urge the rear ends of the trays upwardly against the guide surfaces to urge the front ends of the trays downwardly toward the lugs to latch the trays firmly in position.

Storage system for hot food trays

A programmable electronic control system for an array of electrical stations exemplified by food tray stations each of which is adapted to receive a food tray having two or more electrical heaters embedded in the tray. Each tray is detachable from its station. A separate power circuit is associated with each heater element at each tray station for supplying separately controllable power to each individual heater. A manually controlled programming channel is connected to each power circuit and includes means for generating control signals to enable or disable each separate power circuit to permit the programming of the entire array of tray stations. A manually controlled station reset device is connected to the programming channels for each tray station to remove any enabling control signals generated by the respective programming channels for that station to permit the re-programming of individual tray stations. A manually controlled master reset device is connected to all the programming channels for all the stations to remove any enabling control signals generating by any of the programming channels to permit the re-programming of the entire array of tray stations. A tray sensing device disables the power circuits associated with the respective tray stations whenever trays are absent from the respective stations, and enable the programming channels associated with the respective tray stations whenever trays are present at the respective stations. A locking device is provided for locking in all the control signals to prevent the re-programming or clearing of any of the tray stations after a complete program has been selected.

Growing community of inventors

Mendota Heights, MN, United States of America

Michael C Freund