GB2028224A - Jaw sealing assembly - Google Patents

Jaw sealing assembly Download PDF

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Publication number
GB2028224A
GB2028224A GB7925578A GB7925578A GB2028224A GB 2028224 A GB2028224 A GB 2028224A GB 7925578 A GB7925578 A GB 7925578A GB 7925578 A GB7925578 A GB 7925578A GB 2028224 A GB2028224 A GB 2028224A
Authority
GB
United Kingdom
Prior art keywords
web
sealing
jaws
jaw
layers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7925578A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Imperial Chemical Industries Ltd
Original Assignee
Imperial Chemical Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
Priority to GB7925578A priority Critical patent/GB2028224A/en
Publication of GB2028224A publication Critical patent/GB2028224A/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81433—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined being toothed, i.e. comprising several teeth or pins, or being patterned
    • B29C66/81435—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined being toothed, i.e. comprising several teeth or pins, or being patterned comprising several parallel ridges, e.g. for crimping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F3/00—Severing by means other than cutting; Apparatus therefor
    • B26F3/06—Severing by using heat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • B29C65/24—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools characterised by the means for heating the tool
    • B29C65/30—Electrical means
    • B29C65/305—Electrical means involving the use of cartridge heaters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/74—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area
    • B29C65/745—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area using a single unit having both a severing tool and a welding tool
    • B29C65/7451—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area using a single unit having both a severing tool and a welding tool the severing tool and the welding tool being movable with respect to one-another
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/78—Means for handling the parts to be joined, e.g. for making containers or hollow articles, e.g. means for handling sheets, plates, web-like materials, tubular articles, hollow articles or elements to be joined therewith; Means for discharging the joined articles from the joining apparatus
    • B29C65/7841—Holding or clamping means for handling purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/004—Preventing sticking together, e.g. of some areas of the parts to be joined
    • B29C66/0042—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/004—Preventing sticking together, e.g. of some areas of the parts to be joined
    • B29C66/0042—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined
    • B29C66/0044—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined using a separating sheet, e.g. fixed on the joining tool
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/346—Making joints having variable thicknesses in the joint area, e.g. by using jaws having an adapted configuration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43—Joining a relatively small portion of the surface of said articles
    • B29C66/431—Joining the articles to themselves
    • B29C66/4312—Joining the articles to themselves for making flat seams in tubular or hollow articles, e.g. transversal seams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81411—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat
    • B29C66/81421—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat being convex or concave
    • B29C66/81423—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined characterised by its cross-section, e.g. transversal or longitudinal, being non-flat being convex or concave being concave
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81431—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined comprising a single cavity, e.g. a groove
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8141—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined
    • B29C66/81433—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the surface geometry of the part of the pressing elements, e.g. welding jaws or clamps, coming into contact with the parts to be joined being toothed, i.e. comprising several teeth or pins, or being patterned
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/82—Pressure application arrangements, e.g. transmission or actuating mechanisms for joining tools or clamps
    • B29C66/824—Actuating mechanisms
    • B29C66/8242—Pneumatic or hydraulic drives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832—Reciprocating joining or pressing tools
    • B29C66/8322—Joining or pressing tools reciprocating along one axis
    • B29C66/83221—Joining or pressing tools reciprocating along one axis cooperating reciprocating tools, each tool reciprocating along one axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/84—Specific machine types or machines suitable for specific applications
    • B29C66/849—Packaging machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/912—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux
    • B29C66/9121—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature
    • B29C66/91211—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature with special temperature measurement means or methods
    • B29C66/91212—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature with special temperature measurement means or methods involving measurement means being part of the welding jaws, e.g. integrated in the welding jaws
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/912—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux
    • B29C66/9121—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature
    • B29C66/91231—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature of the joining tool
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9141—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature
    • B29C66/91421—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature of the joining tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9141—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature
    • B29C66/91431—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature the temperature being kept constant over time
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
    • B65B51/00—Devices for, or methods of, sealing or securing package folds or closures; Devices for gathering or twisting wrappers, or necks of bags
    • B65B51/10—Applying or generating heat or pressure or combinations thereof
    • B65B51/26—Devices specially adapted for producing transverse or longitudinal seams in webs or tubes
    • B65B51/30—Devices, e.g. jaws, for applying pressure and heat, e.g. for subdividing filled tubes
    • B65B51/303—Devices, e.g. jaws, for applying pressure and heat, e.g. for subdividing filled tubes reciprocating along only one axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/8122—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the composition of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/816—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the mounting of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8163—Self-aligning to the joining plane, e.g. mounted on a ball and socket
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2905/00—Use of metals, their alloys or their compounds, as mould material
    • B29K2905/08—Transition metals
    • B29K2905/12—Iron

Abstract

A jaw assembly for forming sealed packages from a tubular web in which conventional sealing jaws 10, 11 are supplemented by resiliently biased web engaging plates 24, 25 positioned to engage, and apply a sealing pressure to, at least the edge portions of the collapsed tubular web prior to engagement of the jaws therewith. The jaws 10, 11 are provided with teeth 22 to form crimp seals and with recesses 23 to accommodate a knife blade. Web- engaging plates 24, 25, 34, 35 biased by spring-loaded pins 28, 29 towards the web path are provided on each side of each jaw. The web-engaging faces 26 of the plates 24, 34 are planar but chamfered at 58 and the web-engaging faces 27 of the plates 25,35 are recessed at 59 to accommodate overlapping web portions. In a modification, (Figure 7), supplementary sealing plates form edge-reinforcing seals adjacent the crimp seal. <IMAGE>

Description

SPECIFICATION Jaw sealing assembly This invention relates to a jaw assembly for sealing together a plurality of web layers, and in particular to a thermal sealing assembly for forming heat-seals between adjacent layers of a thermoplastic polymeric film.
Modern packaging techniques frequently involve the formation of a package by creating a seal between two opposed layers of packaging web.
Thus, in the so-called vertical "form and fill" packaging technique a continuous flat web of packaging film is fed around a forming shoulder where it is shaped into tubular form, and thence over a hollow internal mandrel or cylindrical former where the free longitudinal edges of the film are sealed together to create a continuous tubular film. The tubular film then passes between a pair of intermittently cooperating heated sealing jaws which create a series of discrete packages by collapsing the tubular film and forming a succession of horizontal heat-seals, usually crimp seals, across the width of the film, the desired quantity of product being introduced into each package through the internal mandrel in the interval between the formation of successive horizontal heat-seals.
Because of the resistance to deformation of the packaging film that portion of the tubular film compressed between the sealing jaws does not always adopt a completely lay4latform and instead assumes a dumb-bell configuration with a bulbous edge portion extending beyond each side of a compressed central portion of the tube. Creation of a completely hermetic seal across the entire width of the collapsed tube is therefore not readily achieved and the resultant package frequently exhibits a "piping" defect in which an unsealed channel extends through an edge portion of the seal area from the interior of the package, thereby enabling the contents of the package to be exposed to atmospheric contamination and allowing the package to deflate. Such defective packages are commercially unacceptable.
We have now devised an improved jaw sealing assembly which enables the aforementioned defects to be eliminated or substantially reduced.
Accordingly, the present invention provides a jaw assembly for sealing together a plurality of superimposed layers of a web comprising a pair of cooperable sealing jaws moveable to and retractable from an operative position embracing the web path in which the sealing faces of the jaws grip and form a seal between the web layers characterised by a pair of cooperable web engaging members one of which is operatively associated with each jaw, at least one of the members being resiliently biased towards the web path relative to, and having a sealing face projecting inwardly of the sealing face of, the associated jaw, so that as the jaws approach the operative position said members cooperatively engage at least an edge portion of the web layers prior to engagement of the jaws therewith enabling the sealing face of said at least one member to apply a resilient sealing thrust to said edge portions, and, on closure of the jaws, to retract to a median position as hereinafter defined.
The invention further provides a method of sealing together a plurality of superimposed layers of a thermoplastic polymeric film by heating and pressurising said layers in an elongated sealing zone extending between the opposed longitudinal edges of said layers to form a crimp seal having a pattern of longitudinally extending flutes characterised by heating and applying a resilient sealing pressure to said film layers in a region adjacent said sealing zone and extending inwardly from said longitudinal edges to provide a transverse reinforcing seal between said layers at least at the edge portions thereof.
Each sealing jaw may be of any suitable shape but conveniently is in the form of a rectangular block providing a generally rectangular sealing face for engagement with the web, the sealing face being of a width at least equal to, and preferably exceeding, that of the collapsed lay-flat web to be sealed - for example 150 to 200 mm, and having a depth, parallel to the direction in which the web passes between the jaws (the longitudinal or machine direction), sufficient to create a seal of acceptable strength - usually of the order of 10 mm or greater. Each of the long or transverse edges of the sealing face is preferably chamfered to avoid cutting of the web layers when the jaws approach the operative position.
To create an effective seal between the web layers the respective sealing faces of the opposed jaws are preferably provided with a profiled or indented surface pattern - for example, with a regular pattern of serrations interspersed with teeth extending longitudinally on the sealing face parallel to the direction of web travel, the tips of the teeth on one sealing face mating with the serrations on the other sealing face when the jaws are in the operative position.
Each sealing jaw block is suitably fabricated from a rigid material, such as steel or brass, and preferably is adapted to receive means, such as a plurality of electrical cartridge elements, for heating the block to the desired sealing temperature - in the case of heat-sealing jaws. Provision may also be made, if desired, for the inclusion of one or more thermocouples and ancillary temperature control equipment in the block.
To excise successive sealed packages from the continuoustubularweb, knife means are provided conveniently in the form of a retractable blade located within one jaw block in an intermediate recess extending parallel to a long edge thereof.
When the jaws have attained the operative position and sealed the web, the blade traverses the web path into an accommodating recess in the sealing face of the opposed jaw block, thereby severing the seal at a position intermediate the long edges thereof so that the portion of the severed seal downstream of the blade in the direction of travel of the web forms the top seal of one package while the upstream portion of the severed seal forms the bottom of the next succeeding package.
In a preferred embodiment of the invention two pairs of cooperable web engaging members are associated with the jaw assembly, one cooperable pair on the upstream side, and the other cooperable pair on the downstream side, of the jaw assembly in relation to the direction of travel of the web. Each cooperable pair performs an equivalent function, and for ease of description the invention is hereinafter discussed in terms of a single pair of web engaging members.
As hereinbefore described, the cooperable web engaging members operate by engaging at least a longitudinal edge portion of the collapsed tubular web, prior to engagement thereof with the sealing jaws per se, and pressurising the superimposed web layers in that edge region. Each member therefore provides a sealing face for engagement with at least one, and preferably both, of the edge portions of one surface of a layer of the web. Conveniently, the sealing face of each member is of generally rectangular configuration of width not exceeding that of the sealing jaw, and suitably of depth, in the direction of web movement, less than that of the associated jaw. Conveniently, therefore, each web engaging member comprises a generally rectangular plate.
To achieve prior engagement with a web edge portion at least one of the members must be positioned relative to the associated jaw so that the sealing face of that member projects inwardly towards the web path beyond the sealing face of that jaw. However, to avoid cutting the web, while maintaining a sealing pressure thereon, the sealing face of the member should not project inwardly beyond the innermost surface of the associated jaw sealing face when the jaws have closed on the web in the operative sealing position. Accordingly, at least one of the web engaging members should be slideably mounted on the jaw for retraction to a median sealing position in which the member sealing face applies a sealing pressure to the edge portions of the web but does not project inwardly towards the web beyond the innermost surface of the associated jaw sealing face.Maintenance of an adequate sealing pressure is achieved by urging the member into a web engaging position by resilient biasing means such as a coil spring under compression, the required strength of the spring being readily assessed by simple experimentation. The cooperable web engaging member associated with the opposed jaw may be similarly biased, or, if desired, may be fixedly mounted on the jaw - in which case the sealing face of that member should be located at a median sealing position as hereinbefore defined.
Sliding of a member relative to the associated jaw may be assisted by the provision of a lubricating layer therebetween. For example, the sliding surface of the member and/or jaw may be coated with a layer of lubricating material, such as polytetrafluoroethylene, or a shim of polytetrafluoroethylene may be introduced between the associated member and jaw - both to assist sliding movement by reduction of frictional drag and to prevent ingress of contaminants and debris which tend to induce seizure of the sliding mechanism.
To ensure effective sealing of the edge portions of the tubular web at least one of the web engaging members preferably comprises a sealing face which is slightly inwardly tapered from opposed ends towards a central portion thereof so as to present to the web a concave face generally of flattened V form.
Suitably the degree of taper per unit width of the face is of the order of 0.002:1, and an arrangement of this kind readily accommodates any lateral displacements of the tubular web which may occur during a packaging and sealing sequence while ensuring that an adequate sealing pressure is applied to the web edge portions. If desired, a central section of the sealing face may be relieved or recessed and only the end portions thereof tapered for sealing engagement with the edge portions of the tubular web. The sealing face of the opposed cooperable web engaging member may be planar, or correspondingly relieved if desired.
Where the tubular packaging web is formed by folding a flat web over upon itself about a longitudinal axis a double web thickness exists along the length of the tubular web where the overlapped longitudinal edges have been sealed together. The area of the tubular web confined between the sealing jaws therefore includes one zone in which three web layers are superimposed. A web engaging member the sealing face of which is relieved as hereinbefore described not only improves the sealing efficiency of the jaw assembly but also readily accommodates this zone of increased web thickness without damaging the web in the operative sealing position.
If desired one or both of the long edges of the sealing face of a web engaging member may be chamfered to avoid damaging the web during the sealing operation.
The jaw assembly of the invention is of utility in forming packages from webs which can besealed together under pressure, and particularly under a combination of heat and pressure in a heat-sealing operation. Typical heat-sealable webs include thermoplastic polymeric films and laminates thereof, particularly oriented films formed in conventional manner from polymers and copolymers of 1-olefins such as ethylene, propylene, butene-1, and 4methylpentene-1.A useful packaging film cmprises a substrate a high molecularweightstereoregular prdominantly crystalline polymer of propylene, either in the form of a homopolymer or copolymerised with minor quantities (e.g. up to 15% by weight of the copolymer) of at least one other unsaturated monomer, such as ethylene, the substrate having on at least one surface thereof a layer of a heat-sealable - material such as a vinylidene chloride-acrylonitrile copolymer. The technique is also applicable to the formation of packages from a coextruded multiplelayer film having a polypropylene substrate with a heat-sealable surface layer comprising a propylenebutene-1 copolymer.
Packaging webs sealable by the techniques of the invention may vary in thickness over a wide range but preferably have a thickness of from 2 to 150 microns. Packaging films are generally within a thickness range of from 5 to 50 microns.
The invention is illustrated by reference to the accompanying drawings in which Figure 1 is a simplified schematic perspective view of a jaw assembly and associated mountings, Figure 2 is an exploded perspective view, not to scale, of a pair of sealing jaws and associated web engaging members, Figure 3 is a schematic end elevation of a jaw assembly about to grip and collapse a tubular packaging web, Figure 4 illustrates the jaws of Figure 3 in the closed operative sealing position, Figure 5 is a simplified schematic plan view of a pair of cooperable web engaging members approaching the operative sealing position, Figures 6 and 7 illustrate alternative forms of recessed web engaging members in simplified plan view, and Figure 8 schematically illustrates a reinforced seal formedattheendofatubularfilm package.
Referring to Figure 1 of the drawings a pair of sealing jaws 10, 11 is mounted for slideable movement to and from an operative sealing position on guides or runners (not shown) on the internal surfaces of limbs 12,13 of a generally rectangular carriage 14. Reciprocating movement of the respective jaws in a substantially horizontal plane within the carriage is effected by pneumatic assemblies 15, 16 through associated shafts 17, 18.
Carriage 14 is mounted for reciprocating movement in a substantially vertical plane on rails 19, 20.
The sealing face 21 of each jaw is provided with a pattern f elongate teeth 22 cooperable with a mating pattern on the opposed jaw sealing face to form, in the operative position, a crimp seal across the width of a tubular web fed downwardly between the jaws along a web path in a plane embracing rails 19, 10.
An elongated recess 23 in each jaw accommodates a reciprocating knife blade (not shown) which is the operative sealing position traverses the web path to sever the web between opposed horizontal edges of each seal formed therein - thereby creating a series of discrete sealed web packages.
On the uppermost surface of each jaw is located a web engaging member in the form of a generally rectangular plate 24, 25, each plate respectively having a web sealing face 26, 27 and being resiliently biased by a spring-loaded pin 28,29 towards the web path on guide bushes 30,31, located in slots 32, 33. The latter are preferably dimensioned to fit loosely about the respective guide bushes thereby permitting each plate a limited degree of pivotal movement about its spring-loaded pin to ensure that the plates effectively grip and seal a tubular web which may have wandered slightly from its normal central path between the jaws.
A similar pair of cooperable web engaging plates 34,35, of which only one, 34, is visible in Figure 1, is located on the lower surface of the jaws.
Sealing of a tubular web by the assembly involves a cyclic sequence of operations in which carriage 14 moves on rails 19,20 to the upstream end of its stroke where jaws 10, 11 partially close around a tubularweb descending between the rails, the sealing faces of each pair of cooperating plates gripping at least the longitudinal edge portions of the web prior to engagement of the jaws therewith, the carriage assembly descends on the rails to the downstream end of its stroke pulling the web therewith, the jaws and associated plates fully close sealing together with opposed surfaces of the tubular web, the knife blade severs the sealed web, and the jaws and associated plates retract to a open position prior to recycling of the carriage to the upstream end of its stroke.
The jaw and plate assembly is visible in greater detail in the exploded diagram of Figure 2, in which, where possible, identical reference numerals are associated with parts already described by reference to Figure 1. Thus, referring to Figure 2, web engaging plate 24 ia slideably located by guide bushes 30 inserted through slots 32 and secured by pins 50 engaging sockets 51 in the upper surface of jaw 10.
Pin 28, floating in jaw aperture 52 under the influence of coil spring 53 retained under compression in channel 54 by closure plate 55 engages in socket 56 to urge plate 24 inwardly towards the web path. Likewise, resiliently biased pin 29 engages in socket 57 to urge plate 25 inwardly towards the web path.
The sealing face 26 of plate 24 is planar, although the upstream edge 58 thereof is chamfered to avoid damaging the web, while sealing face 27 of cooperating plate 25 is inwardly tapered from each end to provide a slightly recessed section 59 which accommodates the overlapped longitudinally sealed portion of the tubular web (Figure 5). Independently cooperating plates 34, 35 are similarly proportioned and mounted on the respective undersides of jaws 10 and 11.
An orifice, 60, 61 is provided in each jaw to accommodate an electrical heating element (not shown), the web engaging plates being heated indirectly by conduction from, and thereby attaining a temperature substantially identical to that of, the associated jaw. A thermocouple well 62, 63 is also provided in the respective jaws.
The sealing operation is illustrated in Figures 3 and 4.
In Figure 3, the jaw assembly is about to close on opposed layers 70,71 of a tubular web, the sealing faces 21,27,72,73 of the respective plates projecting inwardly towards the web beyond the tips of jaw teeth 22, and knife blade 74 being retracted in recess 23 of jaw 11.
In Figure 4, the jaws have closed to the operative position and sealed the web layers to each other, the sealing faces 21, 27,72,73 of the plates have retracted against the biasing spring to a median position in which they continue to maintain a sealing pressure on the web without cutting through either of layers 70 and 71, and knife blade 74 has been projected into recess 23 in jaw 10 thereby severing the web between the upstream and downstream extremities of the seal.
In the plan view of Figure 5 a collapsed tubular web is shown descending between web engaging plates 24,25 in a plane substantially normal to that of the drawing. At a position approximately midway between the ends of the plates the tubular web, being formed by folding a flat web over upon itself and sealing the overlapped longitudinal free edges of the flat web to each other, comprises three layers 80,81,82, while the collapsed tubular web adopts a dumb-bell configuration with slightly bulbous edge portions 83,84. To accommodate a tubular web of this configuration the sealing face of plate 25 is slightly flared or tapered in the form of a flattened V with limbs 85,86 arranged to present a generally concave surface to the overlap sealed layers 80,81 of the web.The degree of taper may be varied to accommodate webs of different thicknesses, but in general is preferably at least 0.002 inches per inch width of face.
The tapered face of plate 25 cooperating with the planar face 26 of plate 24 not only ensures that the sealing faces of the plates contact bulbous portions 83,84 prior to engagement of the sealing jaws therewith, thereby ensuring that a sealing pressure is applied thereto and maintained for a period longer than that applied to the remainer of the web, but also accommodates the triple-layer central portion of the collapsed tubular web without damge thereto. Later alwanderofthetubularweb is also readily accommodated by the ability of the plates to pivot slightly about pins 28, 29.
The single plate illustrated in Figure 6 has a generally concave sealing face comprising a flat central portion 87 with limbs 88, 89 slightly outwardly inclined thereto, while the single plate illustrated in Figure 7 has a central planar-faced recess 90 flanked by two wings 91,92, the wing faces being outwardly flared in the manner of Figure 6 to a degree of at least 0.002:1.
The sealed packet illustrated in Figure 8 is of the kind frequently employed in the packaging of confectionery, potato crisps, and the like, and includes a conventional crimp seal with a pattern of flutes 95, corresponding to the toothed pattern on the sealing faces of jaws 10,11, extending in the longitudinal or machine direction of the web, i.e. substantially parallel to the direction in which the web travels between the jaws. Supplementary seals 96, 97, extending transversely (substantially normal to a longitudinal edge) of the web, and applied by supplementary sealing plates of the kind shown in Figure 7, reinforce the edge portions of the crimp seal.
The invention is further illustrated by reference to the following Examples.
Example 1 Using a sealing assembly of the kind illustrated in Figures 1 and 2 of the drawings, a series of discrete packages was formed from a flat multiple-layer film of a propylene homopolymersubstrate of 25 microns thickness having on each surface a heatsealable layer comprising a propylene-butene-1 copolymer (88:12 by weight). The flat film had a width of about 250 mm, and each of the resultant packages, including an overlapped longitudinal seal, had a width of about 120 mm.
The sealing jaws of the equipment were maintained at a temperature of 125 C, and seal formation waseffected under a jaw pressure of 35 psi and with a jaw closure time of 0.5 seconds.
Testing of the packages for leakage through the crimped seal area was effected by placing individual packages into a tank of water under a load of 2 kilogrammes and visually assessing the escape of air bubbles from the interior of the package through the seal. Packages tested in this way exhibited a failure rate (escape of bubbles) of 2%, i.e. failure of one end seal was observed from 25 packages (50 end seals).
Example 2 This is a comparative Example, not according to the invention.
Packets formed from identical film and under identical conditions to those of Example 1 except that the supplementary sealing plates were not attached to the jaws of the sealing assembly, when tested by the hereinbefore described procedure exhibited an average failure rate of 100%.

Claims (10)

1. A jaw assembly for sealing together a plurality of superimposed layers of a web comprising a pair of cooperable sealing jaws moveable to and retractable from an operative position embracing the web path in which the sealing faces of the jaws grip and form a seal between the web layers characterised by a pair of cooperable web engaging members one of which is operatively associated with each jaw, at least one of the members being resiliently biased towards the web path relative to, and having a sealing face projecting inwardly of the sealing face of, the associated jaw, so that as the jaws approach the operative position said members cooperatively engage at least an edge portion of the web layers prior to engagement of the jaws therewith enabling the sealing face of said at least one member to apply a resilient sealing thrust to said edge portions, and, on closure of the jaws, to retract to a median position as hereinbefore defined.
2. A jaw assembly according to claim 1 wherein the sealing face of at least one of the members is capable of simultaneously engaging both longitudinal edge portions of one of the web layers.
3. A jaw assembly according to claim 2 wherein the sealing face of said member is concave relative to said web layer.
4. A jaw assembly according to claim 3 wherein said sealing face is ofveeform inwardly tapered from opposed web-engaging ends of the face.
5. A jaw assembly according to claim 4 wherein the sealing face is tapered to a degree of at least 0.002:1.
6. A jaw assembly according to any one of the preceding claims comprising a lubricating layer between the resiliently biased member and the associated jaw.
7. A jaw assembly according to any one of the preceding claims comprising two pairs of cooperable web engaging members, one pair associated respectively with each of the upstream and downstream surfaces of the jaw assembly relative to the direction of travel of the web.
8. A jaw assembly according to any one of the preceding claims comprising means to heat at least one of said jaws to a temperature sufficient to form a heat seal between said web layers.
9. A jaw assembly constructed and arranged substantially as hereinbefore described and with reference to any one of the drawings.
10. A method of sealing together a plurality of superimposed layers of a thermoplatic polymeric film by heating and pressurising said layers in an elongated sealing zone extending between the opposed longitudinal edges of said layers to form a crimp seal having a pattern of longitudinally extending flutes characterised by heating and applying a resilient sealing pressure to said film layers in a region adjacent said sealing zone and extending inwardly from said longitudinal edges to provide a transverse reinforcing seal between said layers at least at the edge portions thereof.
GB7925578A 1978-08-16 1979-07-23 Jaw sealing assembly Withdrawn GB2028224A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7925578A GB2028224A (en) 1978-08-16 1979-07-23 Jaw sealing assembly

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB7833503 1978-08-16
GB7925578A GB2028224A (en) 1978-08-16 1979-07-23 Jaw sealing assembly

Publications (1)

Publication Number Publication Date
GB2028224A true GB2028224A (en) 1980-03-05

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Country Link
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0701943A1 (en) * 1994-04-11 1996-03-20 Yoshino Kogyosho Co., Ltd. Method of and apparatus for forming seal portion of tubular body of synthetic resin
WO1996021595A1 (en) * 1995-01-14 1996-07-18 Pkl Verpackungssysteme Gmbh Method and device for closing filled folding-box packaging containers
EP1066951A2 (en) * 1999-07-05 2001-01-10 Shikoku Kakoki Co., Ltd. Ultrasonic sealing apparatus
WO2007008131A2 (en) * 2005-07-08 2007-01-18 Tetra Laval Holdings & Finance S.A. Device and method for transverse sealing
WO2009048714A1 (en) * 2007-10-11 2009-04-16 Illinois Tool Works Inc. Method of producing a hermetic reclosable package using seal bars with non-parallel geometry
WO2017038330A1 (en) * 2015-08-31 2017-03-09 凸版印刷株式会社 Ultrasonic sealing anvil
WO2019069986A1 (en) * 2017-10-03 2019-04-11 凸版印刷株式会社 Ultrasonic sealing anvil and ultrasonic sealing device
WO2022263087A1 (en) * 2021-06-15 2022-12-22 Rovema Gmbh Transverse sealing unit for producing transverse sealing seams in a tubular bag machine

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0701943A4 (en) * 1994-04-11 1998-10-28 Yoshino Kogyosho Co Ltd Method of and apparatus for forming seal portion of tubular body of synthetic resin
EP0701943A1 (en) * 1994-04-11 1996-03-20 Yoshino Kogyosho Co., Ltd. Method of and apparatus for forming seal portion of tubular body of synthetic resin
WO1996021595A1 (en) * 1995-01-14 1996-07-18 Pkl Verpackungssysteme Gmbh Method and device for closing filled folding-box packaging containers
EP1066951A2 (en) * 1999-07-05 2001-01-10 Shikoku Kakoki Co., Ltd. Ultrasonic sealing apparatus
EP1066951A3 (en) * 1999-07-05 2003-01-02 Shikoku Kakoki Co., Ltd. Ultrasonic sealing apparatus
US6986232B1 (en) 1999-07-05 2006-01-17 Shikoku Kakoki Co., Ltd. Ultrasonic sealing apparatus
EP1904286A4 (en) * 2005-07-08 2015-03-11 Tetra Laval Holdings & Finance Device and method for transverse sealing
WO2007008131A2 (en) * 2005-07-08 2007-01-18 Tetra Laval Holdings & Finance S.A. Device and method for transverse sealing
WO2007008131A3 (en) * 2005-07-08 2007-03-29 Tetra Laval Holdings & Finance Device and method for transverse sealing
US8201606B2 (en) 2005-07-08 2012-06-19 Tetra Laval Holdings & Finance S.A. Device for transverse sealing
WO2009048714A1 (en) * 2007-10-11 2009-04-16 Illinois Tool Works Inc. Method of producing a hermetic reclosable package using seal bars with non-parallel geometry
WO2017038330A1 (en) * 2015-08-31 2017-03-09 凸版印刷株式会社 Ultrasonic sealing anvil
CN107922070A (en) * 2015-08-31 2018-04-17 凸版印刷株式会社 Ultrasonic sealing anvil block
CN107922070B (en) * 2015-08-31 2020-10-09 凸版印刷株式会社 Ultrasonic sealing anvil block
WO2019069986A1 (en) * 2017-10-03 2019-04-11 凸版印刷株式会社 Ultrasonic sealing anvil and ultrasonic sealing device
CN111094138A (en) * 2017-10-03 2020-05-01 凸版印刷株式会社 Anvil block for ultrasonic sealing and ultrasonic sealing device
JPWO2019069986A1 (en) * 2017-10-03 2020-09-10 凸版印刷株式会社 Anvil and ultrasonic sealing device for ultrasonic sealing
CN111094138B (en) * 2017-10-03 2022-04-05 凸版印刷株式会社 Anvil block for ultrasonic sealing and ultrasonic sealing device
WO2022263087A1 (en) * 2021-06-15 2022-12-22 Rovema Gmbh Transverse sealing unit for producing transverse sealing seams in a tubular bag machine

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