Magnetic safety interlock method and apparatus for food processor

In a food processor of the type including tool drive means located in a base housing with control means for rendering the tool drive inoperative unless said control means is actuated, a bowl mountable on said base for enclosing a rotatable tool within said bowl, a removable cover for said bowl, a food feed tube for feeding food items into the bowl to a tool rotatable by said tool drive means, and a food pusher manually insertable into said feed tube for pushing the food items in said feed tube toward the rotating tool, protective interlock apparatus comprising:

• first permanent magnet means associated with the cover,
• said first permanent magnet means becoming positioned in a predetermined position when the bowl is mounted on the base in proper position and when the cover is in proper position on the bowl,
• second permanent magnet means in the base housing coupled with said control means for actuating said control means for rendering the tool drive operative only when said first permanent magnet means has become positioned in said predetermined position, and
• discriminating means associated with said second permanent magnet means for preventing actuation of said control means except by the intended first permanent magnet means.

In a food processor of the type including tool drive means located in a base with control means for rendering the tool drive inoperative unless said control means is actuated, a bowl mountable on said base for enclosing a rotatable tool within said bowl, a removable cover for said bowl, a food-receiving hopper for feeding food items into the bowl to a tool rotatable by said tool drive means, and a food pusher manually insertable into said hopper for pushing the food items in said hopper toward the rotating tool, and wherein an element movably mounted on the bowl is spring-biased in a direction away from the base, and proper positioning of the cover on the bowl causes said movable element to be moved toward the base, improved safety interlock apparatus which comprises:

• a first permanent magnet carried by said movable element,
• a second element movably mounted in the base spring-biased toward the region toward which said first element is moved by said proper positioning of the cover on the bowl when the bowl is also in its proper position on the base,
• a second permanent magnet in the base carried by said second movable element,
• said second movable element being connected to said control means, and
• each of said magnets having a predetermined coded pattern of magnetic polarities,
• whereby the coded pattern of magnetic polarities of said magnets become aligned in registration with each other and said first magnet becomes moved toward the second magnet only when both the cover and bowl are in their respective operating positions,
• thereby repelling said second magnet by said first magnet for moving said second element against the spring bias for actuating said control means to render the tool drive operative, and
• whereby the coded pattern of said second magnet discriminates against repelling by an ordinary permanent magnet for preventing actuation of said control means by an ordinary magnet.

In a food processor of the type including tool drive means located in a base with control means for rendering the tool drive inoperative unless said control means is actuated, a bowl mountable on said base for enclosing a rotatable tool within said bowl, a removable cover for said bowl, a food-receiving hopper extending through the cover for feeding food items through the cover into the bowl to a tool rotatable by said tool drive means, a food pusher manually insertable into said hopper for pushing the food items in said hopper toward the rotating tool, and wherein an element movably mounted on the bowl is spring-biased in a direction away from the base, and proper positioning of the cover on the bowl together with proper positioning of the food pusher into the hopper causes said movable element to be moved toward the base, improved safety interlock apparatus which comprises:

• a first permanent magnet carried by said movable element,
• a second element movably mounted in the base spring-biased toward the region toward which said first element is moved by said proper positioning of the cover on the bowl when the bowl is also in its proper position on the base and when the food pusher has been inserted in the hopper,
• a second permanent magnet in the base carried by said second movable element,
• said second movable element being connected to said control means, and
• each of said magnets having a predetermined coded pattern of magnetic polarities,
• whereby the coded pattern of magnetic polarities of said magnets become aligned in registration with each other and said first magnet becomes moved toward the second magnet only when the cover and bowl and food pusher are all in their respective operating positions,
• thereby repelling said second magnet by said first magnet for moving said second element against the spring bias for actuating said control means to render the tool drive operative, and
• whereby the coded pattern of said second magnet discriminates against repelling by an ordinary permanent magnet for preventing actuation of said control means by an ordinary magnet.

The method of operating a food processor of the type including tool drive means located in a base with control means for rendering the tool drive inoperative unless said control means is actuated, a bowl mountable on said base for enclosing a rotatable tool within said bowl, a removable cover for said bowl, a food-receiving feed tube extending through the cover for feeding food items through the cover into the bowl to a tool rotatable by said tool drive means, and a food pusher manually insertable into said feed tube for pushing the food items in said feed tube toward the rotating tool, said method preventing operation of the tool drive unless preselected manually removable components of the food processor have been properly placed in their respective operating positions comprising the steps of:

• providing first and second permanent magnets having corresponding coded patterns of magnetic polarities,
• mounting said first coded magnet on one of said manually removable components in a predetermined association therewith for causing said first magnet to be brought into a predetermined region near the base only when said preselected components have been properly placed in their respective operating positions,
• movably mounting said second coded magnet in the base,
• biasing said second coded magnet to move toward said predetermined region, and
• connecting said movably mounted second coded magnet to said control means,
• whereby said second coded magnet is repelled and moves against said biasing for actuating said control means for rendering the tool drive operative only when said first magnet has been brought into said predetermined region,
• thereby assuring that said preselected components have been properly placed in their respective operating positions before the tool drive is rendered operative, and
• thereby discriminating against the repelling of said second coded magnet by an ordinary magnet for avoiding actuation of said control means by an ordinary magnet.