GB2248421A - Bag sealing mechanism - Google Patents

Bag sealing mechanism Download PDF

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Publication number
GB2248421A
GB2248421A GB9019910A GB9019910A GB2248421A GB 2248421 A GB2248421 A GB 2248421A GB 9019910 A GB9019910 A GB 9019910A GB 9019910 A GB9019910 A GB 9019910A GB 2248421 A GB2248421 A GB 2248421A
Authority
GB
United Kingdom
Prior art keywords
jaws
jaw
mechanism according
linkage
bag
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.)
Granted
Application number
GB9019910A
Other versions
GB2248421B (en
GB9019910D0 (en
Inventor
Alan Arthur Holt
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.)
Howard Elliot Bell
Original Assignee
Howard Elliot Bell
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 Howard Elliot Bell filed Critical Howard Elliot Bell
Priority to GB9019910A priority Critical patent/GB2248421B/en
Publication of GB9019910D0 publication Critical patent/GB9019910D0/en
Publication of GB2248421A publication Critical patent/GB2248421A/en
Application granted granted Critical
Publication of GB2248421B publication Critical patent/GB2248421B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

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
    • 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
    • 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
    • B29C66/40—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
    • B29C66/43121—Closing the ends of tubular or hollow single articles, e.g. closing the ends of bags
    • 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
    • B29C66/822—Transmission mechanisms
    • B29C66/8221—Scissor or lever mechanisms, i.e. involving a pivot point
    • 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
    • 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
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/92—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools
    • B29C66/924—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the pressure, the force, the mechanical power or the displacement of the joining tools
    • B29C66/9261—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the displacement of the joining tools
    • B29C66/92611—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the displacement of the joining tools by controlling or regulating the gap between the joining tools
    • B29C66/92615—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the pressure, the force, the mechanical power or the displacement of the joining tools by controlling or regulating the displacement of the joining tools by controlling or regulating the gap between the joining tools the gap being non-constant over time

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Package Closures (AREA)

Abstract

A bag sealing mechanism is mounted on a pivoting frame and has opposed jaws (11, 12) for closing a bag (10). The jaws (11, 12) are movable in two stages by actuation means 15, 16, one of the jaws (12) being movable directly and the other (11) indirectly by linkage means 18, 22, the first actuation stage moving the jaws (11, 12) towards each other to a pre-determined separation at which said linkage closely approaches an over centre condition, and the second actuation stage moving said one jaw (12) towards the other jaw (11) thereby to close the bag (10). <IMAGE>

Description

Baa forming and sealing mechanism This invention relates to mechanisms for forming bags from sheet material and particularly to vertical form fill and seal machines of the type used to bag potato crisps.
In such machines sheet material is drawn from a roll over a tube former and the longitudinal edges of the sheet are seamed together to form a vertically extending tube. The tube former also constitutes a filling funnel for the tube.
The tube passes through a bag sealer comprising opposed jaws incorporating upper and lower heating elements and an intermediate mechanical knife. The bag sealer is mounted on a pivoting frame for up and down movement.
In use the bottom of the tube is sealed and a measured quantity of material dispensed through the funnel into the tube, the pivoting frame is in its uppermost position. The jaws of the bag sealer then approach one another to squeeze the tube and at the same time the pivoting frame begins to move the bag sealer downwards relative to the tube.
When the naws are nearly touching, such downward movement will strip the bottom part of the tube of Ir so that the volume of the bag portion is at a minimum. Further inward movement of the jaws will grip the tube and draw it downward; at the same time heating elements within the jaw seal the opposed bag walls together. As the jaws reach the bottommost position the mechanical knife cuts the tube and the jaws open to release the sealed bag and allow the bag sealer to return to the uppermost position; at the same time a quantity of material is being dispensed into the tube for the next bag.
Additional bag squeez;ng devices may be added to ensure that the volume of the bag is at minimum.
The parts of these mechanisms are usually moved by pneumatic cylinders and in one prior machine the jaws are closed by two such cylinders operating in tandem on the sare axls, the first closes the jaws to the strir-ping position whilst the second squeezes the together. This arrangement is very wasteful of space. Parlor art machines also have pneumatic cy@@@ders on both sides of the bag sealer; this arrangement obstructs access to the sealer and may aisc prevent filling and sealing mechanism from being viewed.
It is an object of the present invention to provide a compact forming and sealing mechanism in which the means tor actuating the mechanism is compact and on one side of the bag sealer.
Aooording to the invention there is provided a bag sea@ing mechanism mounted on a pivoting frame and having opposed jaws for closing a bag wherein the çaws are moved in two stages by actuation means, one of said jaws being moved directly and the other being moved indirectly by linkage means, the first actuation stage moving said jaws together to a predetermined separation at which said linkage means approaches an over-centre condition, and the second actuation stage moving said one jaw towards said other jaw to thereby close the bag.
When the linkage means is in the over-centre condition the other jaw is effectively locked against movement during the second stage of movement.
Such an arrangement permits a compact mechanism in wic the aotuation means are located on one side of the dawns. The arrangement allows a modular con-truction in which the jaws may be readily removed for Ieptacement or servicing without disturbing the a@@u@@@@ means. Furthermore the entire mechanism 1nclu4:ng actuation means, may be easily removed for servicing or replacement.
The arrangement allows the bag filling operation to be viewed closely so that fine adjustment may be eas :1 y made.
The actuation means preferably comprises two air cylinders mounted side by side with the output of one cylinder connected to the body of the second by a frame member, and the output of the second connected directly to one of the jaws. The other jaw is connected by a linkage to the frame member so that operation of the first cylinder moves both jaws whereas operation of the second cylinder moves only one of the jaws.
Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example only in the accompanying shemat; drawings in which: Fig 1 is a partial elevation of the bag sealing mechanism of the invention and showing the formed tube in section; Fig 2 is schematic sectional view on line 2-2 of Fig 1; Fig 3 is a schematic sectional view corresponding to Fig 2 but showing the bag sealer almost closed; Fig 4 is an enlarged cross-section through the jaws of the bag sealer; Fig 5 illustrates the sealing and cutting areas of the formed tube; Fig 6 illustrates the mechanical knife and linkage; Fig 7 is an enlarged partial section through the lower part of an alternative jaw; and Fig 8 illustrates the frame on which the bag sealing mechanism is mounted.
With reference to Figs 1 and 2 there is shown a sealing mechanism comprising opposed jaws 11,12 journal led for reciprocal movement on slide bars 13,14. A tube 10 passes through the jaws without obstruction and is sealed at the bottom.
The Jaws are actuated by pneumatic cylinders 15,16 mounted one above the other and operable in tandem by virtue of a frame member 17 which links the output of cylinder 15 with the body of cylinder 16. The slide bars 13,14 and cylinder 15 are mounted on movable frame to be described below.
Movement of jaw 12 is by the output rod of cylinder 16; movement of jaw 11 is by a linkage shown in Fig 2.
Jaw 11 is linked by connecting rods 18 to pivot members 19 also mounted on the movable frame. An arm 21 of each member 19 respectively connects rods 18 with rods 22 linked to an extension of frame member 17.
The rods 19 and 22 are pin jointed to allow a sufficient degree of articulation.
In use ectuat ion of cylinder 15 moves frame member 17 and cylinder 16, and hence the naws 11,12 to the position shown in Fig 3 in which the tube is squeezed almost closed. In this position the rods 19 are about to move over the pivot points of arms 21. The gap between the jaws is of the order of 4-5 mm to allow air to escape as the bag is stripped.
Actuation of cylinder 16 moves only jaw 12 to squeeze the tube tightly and at the same time heating elements in one or both jaws are energised to seal the walls of the tube together. Movement of the rods 9 or the centre of the pivot points of arms 21 is the jaw 11 against any substantial movement during the sealing operation and jaw 11 thereby provides a steady anvil for jaw 12.
Fig 4 shows the jaws in the almost closed position of Flg 3. Each jaw is shown with an upper and lower heating element 23 although only one upper and one lower element may be provided in some circumstances.
When the wails of the tube 24 are pressed together the heating elements seal the tube in two bands, as shown in Fig 5, and a mechanical knife 25 cuts the tube intermediate the bands as illustrated in Fig 5 by the dotted line. The sealed bag drops into a box and the tube is ready to receive another filling.
The knife may take the form of a blade mounted in one Dew on a trapezium linkage, as shown in Fig 6, and movable into a slot of the other jaw by a pneumatic clinder mounted close by.
The base of one or each jaw may have a lightly sprig loaded blade 26 to gently press the walls of the tube together during stripping.
The above sealing mechanism is mounted on a pivoting frame shown schematically in Fig 8. The frame may be pin jointed for parallel movement of opposite arms and is pivoted about the machine frame as shown. One or more air cylinders 27 actuate the frame which may be counterbalanced by a weight 28; the sealing mechanism being mounted on the front upright leg 29 by any convenient means.

Claims (5)

CLAIMS:
1. A bag sealing mechanism mounted on a pivoting frame and having opposed jaws for closing a bag wherein the jaws are movable in two stages by actuation means, one of the jaws being movable directly and the other being movable indirectly by linkage means, the first actuation stage moving said jaws toward each other to a pre-determined separation at which said linkage closely approaches an over-centre condition, and the second actuation stage moving said one jaw towards said other jaw to thereby close the bag.
2. A mechanism according to Claim 1 and further including actuation means having a two stage output displacement.
3. Amechanism according to Claim 2 wherein said actuation means comprise two actuators operable sequentially, the output of the first actuator being connected to said linkage means and to the body of the second actuator, and the output of said second actuator being connected to said one jaw.
4. A mechanism according to Claim 3 wherein said linkage comprises twin 3 bar linkages connected one to each side of said other jaw and each having a centre pivot for the middle link.
5. A mechanism according to claim 4 wherein the middle link of each of said linkages is substantially perpen dicular to the direction of actuation when said mechanism
5. A mechanism according to Claim 4 wherein the middle link of each of said linkages is substantially perpendicular to the direction of actuation when said mechanism is in the starting condition.
6. A mechanism according to Claim 4 or Claim 5 wherein in the over centre condition the link between the middle link and said other jaw lies over the centre pivot of said middle link.
7. A mechanism according to any of Claims 3 to 6 wherein said actuators are air operated pneumatic cylinders mounted one above the other.
8. A mechanism according to any preceding Claim wherein each of said jaws includes a heating element.
9. A mechanism according to any preceding Claim wherein one of said jaws includes a mechanical knife mounted on a trapezium linkage in a recess of the jaw.
10. A mechanism according to any preceding Claim wherein said pivoting frame is a four bar pin-jointed linkage, one of the vertically extending bars being stationary and said jaws being mounted on the opposite vertically extending bar, a third bar being extended in a generally horizontal direction to provide an actuating lever for the linkage.
11. A mechanism according to Claim 10 wherein the actuating lever extends beyond a fixed pivot of the frame.
12. A mechanism substantially as described herein with reference to the accompanying drawings.
Amendments to the claims have been filed as follows 1. A bag sealing mechanism mounted on a pivoting frame and having opposed jaws for closing a bag wherein the jaws are movable to close the bag in two stages by actuation means, in the first stage one of the jaws being movable directly by the actuation means and the other being movable indirectly through linkage means so that said jaws are moved toward each other to a pre-determined separation at which said linkage closely approaches an over-centre condition, and in the second actuation stage moving said one jaw towards said other jaw to thereby close the bag.
2. A mechanism according to claim 1 and further including actuation means having a two stage output displacement.
3. A mechanism according to claim 2 wherein said actuation means comprise two actuators operable sequentially, the output of the first actuator being connected to said linkage means and to the body of the second~ actuator, and the output of said second actuatcr being connected to said one jaw.
4. A mechanism according to claim 3 wherein said linkage comprises twin 3 bar linkages connected one to each side of said other jaw and each having a centre pivot for the middle link.
GB9019910A 1990-09-12 1990-09-12 Bag forming and sealing mechanism Expired - Fee Related GB2248421B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9019910A GB2248421B (en) 1990-09-12 1990-09-12 Bag forming and sealing mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9019910A GB2248421B (en) 1990-09-12 1990-09-12 Bag forming and sealing mechanism

Publications (3)

Publication Number Publication Date
GB9019910D0 GB9019910D0 (en) 1990-10-24
GB2248421A true GB2248421A (en) 1992-04-08
GB2248421B GB2248421B (en) 1994-04-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9019910A Expired - Fee Related GB2248421B (en) 1990-09-12 1990-09-12 Bag forming and sealing mechanism

Country Status (1)

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GB (1) GB2248421B (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1011359A (en) * 1962-07-14 1965-11-24 Hamac Hansella Ag A method and device for the production of filled tubular bag wrappings

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1011359A (en) * 1962-07-14 1965-11-24 Hamac Hansella Ag A method and device for the production of filled tubular bag wrappings

Also Published As

Publication number Publication date
GB2248421B (en) 1994-04-06
GB9019910D0 (en) 1990-10-24

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940912