Mobile food serving system

Claim 2

A mobile food serving system for maintaining food at a desirable serving temperature, said system comprising a mobile cart having at least one tray supporting rack, a self-contained electrical energy source carried by and movable with the cart, a tray removably supported on the rack and having a supporting surface for food containers, at least one localized contact heat transfer device in said surface with a substantial portion of the surface free of such devices, said tray carrying electrical contacts, each localized heat transfer device comprising an electrical heater in thermal contact with a localized surface area of the tray for good heat transfer thereto, each tray heat transfer device being electrically insulated and thermally insulated from other portions of said tray so that food can be maintained heated at said localized surface area while other areas of said tray surface can carry food without heating said last-mentioned food, electrical connecting means including mating electrical contacts on said rack and a switch for supplying energy from the source on the cart to the heat transfer device on the tray surface through said tray contacts to energize said device when the tray is on the rack on the cart, and a food container arranged in direct contact heat exchange relationship with the localized heat transfer device so as to transmit heat between the device and the food contained therein.

Claim 3

A system as described in claim 1 further characterized by said food container having a bottom surface that generally conforms to the surface of the heat transfer device so that the container bottom has substantial surface to surface contact therewith, and means in the tray surface for assisting in positioning and retaining the container on the heat transfer device.

Claim 4

A system as described in claim 2 further characterized by said tray having more than one heat transfer device, and means operatively associated with each heat transfer device capable of maintaining the different devices at different preselected temperatures.

Claim 5

A system as described in claim 3 further characterized by said tray being made of thermal insulating material, and each heat transfer device in the tray being thermally insulated from other heat transfer devices in said tray.

Claim 6

A system in accordance with claim 2 wherein each contact heat transfer device is air insulated from a lower surface of each tray opposite said supporting surface of each tray.

Claim 7

A system in accordance with claim 2 wherein said last-mentioned means comprises an upstanding peripheral boss precluding lateral movement of said container.

Claim 8

A system as described in claim 1 further characterized by said food container being made of thin sheet plastic material to enhance ease of heat transfer to food in said container.

Claim 9

A system in accordance with claim 1 wherein each contact heat transfer device comprises a positive temperature coefficient electric heating element.

Claim 10

A mobile food serving system in accordance with claim 1 wherein said tray comprises, said supporting surface being horizontal and having an upturned edge portion, an opening in the support generally corresponding in size to the bottom surface of a food container, a circuit assembly base secured to the bottom of the tray and aligned with the opening, a disc on the tray made of good heat conductive material and generally conforming in shape to the opening and aligned with the opening, said disc and base forming a closed cavity in the tray, said heat transfer device being in contact with the bottom of the disc and with its bottom spaced from the base and lying in the cavity, and the electrical tray contact connected to the heat transfer device by conductors in the cavity for carrying energy to the device to energize it.

Claim 11

A mobile food serving system for maintaining food at a desirable serving temperature, said system comprising a mobiLe cart having a plurality of tray supporting racks, a self-contained, rechargeable electrical battery carried by and movable with the cart, a plurality of trays being removably supported on the racks and each having a surface for carrying food, a plurality of localized contact heat transfer devices arranged in said surface of each tray when the trays are mounted on the racks, said trays each carrying electrical contacts, each localized heat transfer device comprising an electrical heater in thermal contact with a localized surface area of the tray for good heat transfer thereto, each tray heat transfer device being electrically insulated and thermally insulated from other portions of said tray so that food can be maintained heated at said localized surface area while other areas of said tray surface can carry food without heating said last-mentioned food, electrical connector means including mating cart electrical contacts for contact with said electrical contacts of said trays and a switch for connecting the devices and the battery, said electrical connector means further including means for energizing preselected ones of said trays.

Claim 12

A mobile food serving system for maintaining food at a desirable serving temperature, said system comprising a mobiLe cart having a plurality of tray supporting racks, a self-contained, rechargeable electrical battery carried by and movable with the cart, a plurality of trays being removably supported on the racks and each having a surface for carrying food, a plurality of localized contact heat transfer devices arranged in said surface of each tray when the trays are mounted on the racks, said trays each carrying electrical contacts, each localized heat transfer device comprising an electrical heater in thermal contact with a localized surface area of the tray for good heat transfer thereto, each tray heat transfer device being electrically insulated and thermally insulated from other portions of said tray so that food can be maintained heated at said localized surface area while other areas of said tray surface can carry food without heating said last-mentioned food, electrical connector means including mating cart electrical contacts for contact with said electrical contacts of said trays and a switch for connecting the devices and the battery, said electrical connector means further including means for energizing preselected ones of said trays.

Claim 13

A food serving system as described in claim 10 further characterized by said devices being embedded in the tray surfaces and the trays being made of a thermal insulating material, and at least one food container on each tray in contact heating relationship with one of said contact heat transfer devices.

Claim 14

A food serving system as described in claim 11 further characterized by means operatively associated with each device for retaining the temperature of food in containers on said devices at a preselected level.

Claim 15

A system as described in claim 11 further characterized by drive means for propelling said cart, said drive means being powered by a self-contained electrical energy source, and control means for actuating and deactuating said drive means.

Claim 16

A system as described in claim 13 wherein said trays and food container are formed of an organic plastic.

Claim 17

A system in accordance with claim 11 and further comprising, means for retaining said trays on said racks, said electrical connector means further including mating electrical contacts on said trays and said racks and means for urging said contacts into resilient engagement with each other.

Claim 18

A food serving system as described in claim 10 further characterized by single service food containers having bottom surfaces that generally correspond in size and shape to the surfaces heated by said heat transfer devices and removably placed on the devices, and a cover sized to fit the containers.

Claim 19

A system in accordance with claim 10 wherein each contact heat transfer device comprises a positive temperature coefficient electric heating element.

Claim 20

A mobile food serving system comprising a mobile cart for movement about the floor of an institution such as a hospital and controlled by a single operator, a self-contained, rechargeable, low voltage power pack on and movable with the cart, an array of racks for food serving trays arranged in a column on the cart, electrical terminals for each rack on the cart and connected to the power pack, a plurality of substantially identical food serving trays fitting on and removable from the racks, said trays being made of thermal insulating material and each having a supporting surface to carry a plurality of food containers that constitute the dinnerware for a single person, at least one localized contact heater in each tray supporting surface providing a source of heat over a finite area that comprises a small portion of the entire surface so as to leave a substantial portion of the surface unheated so that it may carry containers with food not to be heated, said trays being formed of insulating means for thermally insulating said heaters to allow contact heating of said finite aRea while permitting other containers to remain unheated, means carried by each tray for connecting its localized heaters to a terminal when the tray is placed on a rack so as to connect said heaters to said power pack, means associated with each heater for maintaining the food in the containers in contact with the heaters at a preselected temperature level, and a plurality of individual food containers carried on and removed at will from the tray surface with at least one container on a localized heater, said one container being made to conduct heat from the heater to the food within it, said one container having a removable cover.

Claim 21

A mobile food serving system comprising a mobile cart for movement about the floor of an institution such as a hospital and controlled by a single operator, a self-contained, rechargeable, low voltage power pack on and movable with the cart, an array of racks for food serving trays arranged in a column on the cart, electrical terminals for each rack on the cart and connected to the power pack, a plurality of substantially identical food serving trays fitting on and removable from the racks, said trays being made of thermal insulating material and each having a supporting surface to carry a plurality of food containers that constitute the dinnerware for a single person, at least one localized contact heater in each tray supporting surface providing a source of heat over a finite area that comprises a small portion of the entire surface so as to leave a substantial portion of the surface unheated so that it may carry containers with food not to be heated, said trays being formed of insulating means for thermally insulating said heaters to allow contact heating of said finite aRea while permitting other containers to remain unheated, means carried by each tray for connecting its localized heaters to a terminal when the tray is placed on a rack so as to connect said heaters to said power pack, means associated with each heater for maintaining the food in the containers in contact with the heaters at a preselected temperature level, and a plurality of individual food containers carried on and removed at will from the tray surface with at least one container on a localized heater, said one container being made to conduct heat from the heater to the food within it, said one container having a removable cover.

Claim 22

A food serving system as described in claim 18 further characterized by said heaters in the trays being sealed so that the trays are immersible.

Claim 23

A food serving system as described in claim 18 further characterized by a plurality of switches electrically connected to the heaters and power pack to maintain different heaters at different preselected temperatures when desired.

Claim 24

A food serving system in accordance with claim 20 wherein a second contact heater is positioned in each tray at a second finite area of each tray.

Claim 25

A food serving system as described in claim 18 further characterized by said racks supporting the trays in spaced apart relation to one another, and said means carried by each tray being electrical contacts extending downwardly from the bottom surfaces of the trays, and said terminals being mounted in the racks for automatically engaging the contacts when the trays are mounted on said racks.

Claim 26

A system as defined in claim 14 further characterized by said cart being open on one side to provide access to the column of racks from the open side thereof, said terminals being disposed in the racks remote from the open side thereof, and drive means connected to said power pack which acts to cause movement of said cart.