Microwave heating apparatus

Claim 2

Microwave heating apparatus comprising: a microwave energy source, means defining a cavity coupled to the energy source and tuned to resonate at the frequency of the source, an inlet port in a first side of said cavity, an outlet port in a second side of said cavity, an arrangement for transporting articles to be heated into the cavity through the inlet port, for holding the articles stationary in the cavity during heating, and for removing the heated articles from the cavity through the outlet port, respective doors for closing the inlet and outlet ports during heating of an article within the cavity, a portion of the inner surface of each door when closed defining part of the respective cavity wall, and means for inhibiting operation of the source while either door is not fully closed, wherein said cavity includes spaced side walls and spaced end walls defining thereBetween a generally rectangular space, wherein said inlet and outlet ports comprise respective rectangular openings in said end walls, wherein said transport arrangement comprises a motordriven endless belt of dielectric material arranged to run through said cavity at the level of lower edges of said inlet and outlet ports, and wherein said doors are operable to close said ports by respective downward movements across said ports until a lower edge of each door contacts said belt, followed by respective inward movements to clamp said doors firmly over said ports.

Claim 3

Microwave heating apparatus comprising: a microwave energy source, means defining a cavity coupled to the energy source and tuned to resonate at the frequency of the source, an inlet port in a first side of said cavity, an outlet port in a second side of said cavity, an arrangement for transporting articles to be heated into the cavity through the inlet port, for holding the articles stationary in the cavity during heating, and for removing the heated articles from the cavity through the outlet port, said transport arrangement comprising a belt arranged to run through said cavity at the level of lower edges of said inlet and outlet ports, respective doors for closing the inlet and outlet ports during heating of an article within the cavity, a portion of the inner surface of each door when closed defining part of the respective cavity wall, and means for inhibiting operation of the source while either door is not fully closed, including a respective mechanism supporting each of said doors and operable to provide a composite door closing movement to initially move said doors downwardly across said inlet and outlet ports until a lower edge of each door contacts said belt and to then pull each door inwardly to clamp said doors firmly over said ports, each such mechanism comprising: parallel first levers pivoted about a common axis, one to each of said side walls; door actuator means connected to a first point on each first lever remote from the axis thereof; parallel second levers pivoted at respective points intermediate their ends one to each of said of said first levers at second points on the respective first levers remote from the axis thereof; and respective resilient bias means linking a first end of each said second lever to a point on said respective first lever; the second end of each said second lever being pivoted to one side of the respective door.

Claim 4

Microwave heating apparatus comprising: a microwave energy source, means defining a cavity coupled to the energy source and tuned to resonate at the frequency of the source, an inlet port in a first side of said cavity, an outlet port in a second side of said cavity, an arrangement for transporting articles to be heated into the cavity through the inlet port, for holding the articles stationary in the cavity during heating, and for removing the heated articles from the cavity through the outlet port, said transport arrangement comprising a belt arranged to run through said cavity at the level of lower edges of said inlet and outlet ports, respective doors for closing the inlet and outlet ports during heating of an article within the cavity, a portion of the inner surface of each door when closed defining part of the respective cavity wall, and means for inhibiting operation of the source while either door is not fully closed, including a respective mechanism supporting each of said doors and operable to provide a composite door closing movement to initially move said doors downwardly across said inlet and outlet ports until a lower edge of each door contacts said belt and to then pull each door inwardly to clamp said doors firmly over said ports, each such mechanism comprising: parallel first levers pivoted about a common axis, one to each of said side walls; door actuator means connected to a first point on each first lever remote from the axis thereof; parallel second levers pivoted at respective points intermediate their ends one to each of said of said first levers at second points on the respective first levers remote from the axis thereof; and respective resilient bias means linking a first end of each said second lever to a point on said respective first lever; the second end of each said second lever being pivoted to one side of the respective door.

Claim 5

Apparatus as set forth in claim 13 wherein said cavity further includes a shell of dielectric material forming a tunnel in said cavity and spaced from said side and end walls, through which articles to be heated are passed, said endless belt running along the floor of said tunnel.

Claim 6

Microwave heating apparatus comprising: a microwave energy source, means defining a cavity coupled to the energy source and tuned to resonate at the frequency of the source, an inlet port in a first side of said cavity, an outlet port in a second side of said cavity, an arrangement for transporting articles to be heated into the cavity through the inlet port, for holding the articles stationary in the cavity during heating, and for removing the heated articles from the cavity through the outlet port, respective doors for closing the inlet and outlet ports during the heating of an article within the cavity, a portion of the inner surface of each door when closed defining part of the respective cavity wall, and means for inhibiting operation of the source while either door is not fully closed, in which apparatus said cavity includes spaced side walls and spaced end walls defining therebetween a generally rectangular space, said inlet and outlet ports comprise respective openings in said end walls, said transport arrangement is arranged to run through said cavity at the level of lower edges of said inlet and outlet ports, and said doors are operable to clOse said ports by respective downward movement across said ports.

Claim 7

Microwave heating apparatus comprising: a microwave energy source, means defining a cavity coupled to the energy source and tuned to resonate at the frequency of the source, an inlet port in a first side of said cavity, an outlet port in a second side of said cavity, an arrangement for transporting articles to be heated into the cavity through the inlet port, for holding the articles stationary in the cavity during heating, and for removing the heated articles from the cavity through the outlet port, respective doors for closing the inlet and outlet ports during the heating of an article within the cavity, a portion of the inner surface of each door when closed defining part of the respective cavity wall, and means for inhibiting operation of the source while either door is not fully closed, in which apparatus said cavity includes spaced side walls and spaced end walls defining therebetween a generally rectangular space, said inlet and outlet ports comprise respective openings in said end walls, said transport arrangement is arranged to run through said cavity at the level of lower edges of said inlet and outlet ports, and said doors are operable to clOse said ports by respective downward movement across said ports.

Claim 8

Apparatus as set forth in claim 4, wherein said downward movements of said doors across said ports are followed by respective inward movements of said doors to clamp the same firmly over said ports.

Claim 9

Apparatus as set forth in claim 4, wherein said inlet and outlet ports comprise respective rectangular openings in said end walls.

Claim 10

Apparatus as set forth in claim 4, wherein said transport arrangement comprises a motor-driven endless belt.

Claim 11

Apparatus as set forth in claim 7, wherein said motor-driven endless belt is of a dielectric material.

Claim 12

Apparatus as set forth in claim 4, including a respective mechanism supporting each of said doors and operable to provide a composite door closing movement to initially move said doors downwardly across said inlet and outlet ports until a lower edge of each door contacts said belt and then to pull each door inwardly to clamp said doors firmly over said ports, each such mechanism comprising: parallel first levers pivoted about a common axis, one to each of said side walls; door actuator means connected to a first point on each first lever remote from the axis thereof; parallel second levers pivoted at respective points intermediate their ends one to each of said first levers at second points on the respective first levers remote from the axes thereof; and respective resilient bias means linking a first end of each said second lever to a point on said respective first lever; the second end of each said second lever being pivoted to one side of the respective door.

Claim 13

Apparatus as set forth in claim 4, wherein said cavity further includes a shell of dielectric material forming a tunnel in said cavity and spaced from said side and end walls, through which articles to be heated are passed, said endless belt running along the floor of said tunnel.