Tray sealing system incorporating beaded seal plate

• US 20020074091A1
• Filed: 11/27/2001
• Published: 06/20/2002
• Est. Priority Date: 11/27/2000
• Status: Active Grant

• Current Assignee: Harpak, Inc.
• Original Assignee: Harpak, Inc.
• Inventors: Faherty, Vincent E.
• Granted Patent: US 6,701,993 B2
• Time in Patent Office: Days
• US Class Current: 156/583.3
• CPC Class Codes: B29C 65/18 using heated tools
• CPC Class Codes: B29C 65/305 involving the use of cartridge heaters
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/131 Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
• CPC Class Codes: B29C 66/232 said joint lines being multiple and parallel, i.e. the joint being formed by several parallel joint lines
• CPC Class Codes: B29C 66/24244 forming a rectangle
• CPC Class Codes: B29C 66/53461 joining substantially flat covers and/or substantially flat bottoms to open ends of container bodies
• CPC Class Codes: B29C 66/7373 Joining soiled or oxidised materials
• CPC Class Codes: B29C 66/81427 comprising a single ridge, e.g. for making a weakening line; comprising a single tooth
• CPC Class Codes: B29C 66/81431 comprising a single cavity, e.g. a groove
• CPC Class Codes: B29C 66/81457 comprising a block or layer of deformable material, e.g. sponge, foam, rubber pressing elements supported or backed-up by resilient material B29C66/8161
• CPC Class Codes: B29C 66/8227 using springs
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/8432 Machines for making separate joints at the same time mounted in parallel or in series
• CPC Class Codes: B29C 66/849 Packaging machines
• CPC Class Codes: B29L 2031/712 Containers; Packaging elements or accessories, Packages closures therefor B29L2031/56; ink or toner cartridges B29L2031/7678; squeeze tubes B29L2023/20; suitcases B29L2031/7418
• CPC Class Codes: B29L 2031/7162 Boxes, cartons, cases

Abstract

A tray sealing assembly includes a seal support frame for supporting a flange of a tray during sealing of a sealing film to the flange, a seal plate having a sealing surface provided with a raised bead, and a heater for heating the seal plate. The seal support frame is movable relative to the seal plate between a retracted position and a seal position in engagement with the seal plate. Preferably, the raised bead forms a continuous closed loop on the sealing surface. The raised bead produces a reliable seal between the sealing film and the tray flange, despite the presence of contaminants on the tray flange.

Claims

1. A tray sealing assembly comprising:

a seal support frame for supporting a flange of a tray during sealing of a sealing film to the flange;

a seal plate having a sealing surface provided with a raised bead, said seal support frame being movable relative to said seal plate between a retracted position and a seal position in engagement with said seal plate; and

a heater for heating the seal plate.

2. A tray sealing assembly as defined in claim 1 wherein said raised bead comprises a continuous closed loop on said sealing surface.

3. A tray sealing assembly as defined in claim 1 wherein said raised bead comprises a single closed loop on said sealing surface.

4. A tray sealing assembly as defined in claim 1 wherein said raised bead comprises two or more closed loops on said sealing surface.

5. A tray sealing assembly as defined in claim 1 wherein said raised bead has a rounded cross section.

6. A tray sealing assembly as defined in claim 1 wherein said raised bead has a cross section that avoids sharp edges.

7. A tray sealing assembly as defined in claim 1 wherein said raised bead has a height above said sealing surface of about 1.5 millimeters.

8. A tray sealing assembly as defined in claim 7 wherein said raised bead has a width of about 3 millimeters.

9. A tray sealing assembly as defined in claim 1 further comprising an actuator for moving said seal support frame between the seal position and the retracted position.

10. A tray sealing assembly as defined in claim 1 further comprising a source of sealing film for supplying the sealing film between the seal support frame and the seal plate.

11. A tray sealing assembly as defined in claim 1 further comprising an enclosure surrounding said seal support frame and said seal plate and a source of inert gas coupled to the enclosure, wherein the inert gas is sealed in the tray.

12. A tray sealing assembly as defined in claim 1 wherein said raised bead is configured to displace contaminants, thereby forming a seal between the sealing film and the flange at least in the region of the raised bead.