GB2244236A - A method and apparatus for sealing - Google Patents

A method and apparatus for sealing Download PDF

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Publication number
GB2244236A
GB2244236A GB9011416A GB9011416A GB2244236A GB 2244236 A GB2244236 A GB 2244236A GB 9011416 A GB9011416 A GB 9011416A GB 9011416 A GB9011416 A GB 9011416A GB 2244236 A GB2244236 A GB 2244236A
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GB
United Kingdom
Prior art keywords
sealing
press
radio frequency
platen
plastics sheets
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
GB9011416A
Other versions
GB2244236B (en
GB9011416D0 (en
Inventor
Robert Nohilly
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.)
CASEY TECHNOLOGY Ltd
Original Assignee
CASEY TECHNOLOGY Ltd
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Filing date
Publication date
Application filed by CASEY TECHNOLOGY Ltd filed Critical CASEY TECHNOLOGY Ltd
Publication of GB9011416D0 publication Critical patent/GB9011416D0/en
Publication of GB2244236A publication Critical patent/GB2244236A/en
Application granted granted Critical
Publication of GB2244236B publication Critical patent/GB2244236B/en
Anticipated expiration legal-status Critical
Expired - Fee Related 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
    • 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
    • B29C65/04—Dielectric heating, e.g. high-frequency welding, i.e. radio frequency welding of plastic materials having dielectric properties, e.g. PVC
    • 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
    • B29C65/72—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by combined operations or combined techniques, e.g. welding and stitching
    • 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
    • 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
    • B29C65/7858—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 characterised by the feeding movement of the parts to be joined
    • B29C65/7861—In-line machines, i.e. feeding, joining and discharging are in one production line
    • B29C65/7864—In-line machines, i.e. feeding, joining and discharging are in one production line using a feeding table which moves to and fro
    • 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
    • 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
    • B29C66/83—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

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Closing Of Containers (AREA)

Abstract

Apparatus 1 for sealing together plastics sheets 2, 3, 4 (figure 9) used in forming a tourniquet cuff 6 comprises a support framework 10 supporting a table 11 having guide rails 13 and a platen 14 for receiving plastics sheets to be sealed. A sealing press 20 includes a sealing head 26 operated by a ram 27. The head 26 includes an electrode 30 to which radio frequency energy is transmitted from a generator 31. The electrode 30 is preheated by heating plates 35 (figure 4) connected in parallel so that the maximum power from the radio frequency generator 31 is applied to seal the plastics sheets 2, 3, 4. The heat transferred by plates 35 is controlled by rheostat 40. <IMAGE>

Description

"A Method and Apparatus for Sealina" The invention relates to a method and apparatus for sealing together portions of at least two plastics sheets.
According to one aspect of the invention there is provided an apparatus for sealing together portions of at least two plastics sheets comprising: a table assembly comprising a support framework and a platen mounted on the framework for receiving plastics sheets to be sealed; a sealing press having a sealing die, the press being movable relative to the platen from an inactive position with the platen exposed for receiving plastics sheets to a sealing position to seal portions of the plastics sheets on the platen, means for passing radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in the sealing position, and pre-heating means for pre-heating the sealing die prior to movement of the press to the active position and prior to application of radio frequency electromagnetic energy through the die.
In one embodiment of the invention switch means are provided to de-activate the pre-heating means when the press is moved to the sealing position.
Preferably the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moped to the sealing position.
Preferably the apparatus includes control means for controlling the temperature to which the sealing die is heated. Typically the control means comprises a rheostat.
In one embodiment of the invention the heating means comprises a heating plate means for heat transfer to the sealing die.
Preferably the plate means are electrically heated.
In a preferred arrangement the heating plate means comprises at least two plate means spaced-apart along the sealing die.
Preferably the plate means are connected in parallel.
In one embodiment of the invention the table assembly includes guide means in which the platen is slidably mounted for movement into and out of alignment with the sealing press.
Preferably the sealing press is operated by a ram means.
Preferably the means for passing radio frequency energy from the sealing die through portions of the plastics sheets comprises a radio frequency generator, a transmitting electrode defined by the sealing die and a receiving electrode defined by the platen.
Preferably the radio frequency generator transmits radio frequency energy in the range of 27MHz.
In a particularly preferred arrangement the sheets of plastics material form, in use, at least part of a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow.
The invention also provides a method of sealing together portions of at least two plastics sheets using the apparatus of the invention, the method comprising the steps of: placing the plastics sheets to be joined on a support platen, pre-heating the sealing die of a sealing press by a pre heating means, moving the sealing die onto the plastics sheets while de activating the pre-heating means, applying radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in a sealing position, releasing the press, and removing the sealed plastics sheets from the platen.
In one embodiment of the invention the radio frequency energy is applied by a radio frequency energy generator, a transmitter electrode defined by the sealing die and a receiving electrode defined by the platen.
Preferably the radio frequency generator transmits radio frequency energy in the range of 27MHz.
In one arrangement the pre-heating means is de-activated by a switch means.
Preferably the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moved to the sealing position.
In a particularly preferred arrangement the pre-heating means comprises a heating plate means for heat transfer to the sealing die.
Preferably the plate means are electrically heated.
In a preferred arrangement the heating plate means comprise at least two plate means spaced-apart along the sealing die.
Preferably the plate means are connected in parallel.
In a preferred arrangement the table assembly includes guide means in which the platen is slidably mounted for movement into an out of alignment with the sealing press.
In a particularly preferred arrangement the plastics sheets material form, in use at least part of a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow.
The invention also provides plastics sheets whenever sealed by an apparatus according to the invention or by a method according to the invention. In particular, the invention provides a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow whenever made by the apparatus or method according to the invention.
The invention will be more clearly understood from the tcllowing description thereof given by way of example only wirh reference to the accompanying drawings in which: ig. 1 is a perspective view of a sealing apparatus ac-ording to the invention in an inactive position, Fig. ~ is a perspective view of the apparatus of Fig. 1 in a sling position, Fig. 3 is a side, partially cross-sectional view on an enlarged sc#1e of portion of the apparatus, Fig. 4 is a perspective partially exploded view of a sealing head portion of the apparatus, Fig. 5 is a plan viw W of the portion of the apparatus of Fig. 4, Fig. 6 is a perspective view of another sealing apparatus, Fig. 7 is a side elevational view of the sealing apparatus of Fig. 6, Fig. 8 is a perspective view of a tourniquet cuff formed using the apparatus of the invention, and Fig. 9 is a diagrammatic exploded view of part of the tourniquet cuff of Fig. 8.
Referring to the drawings and initially to Figs. 1 to 5 thereof there is illustrated an apparatus indicated generally by'the reference numeral 1 for sealing together portions of at least two plastics sheets such as plastics sheets 2, 3, 4 used in forming a tourniquet cuff 6 as illustrated in Figs. 8 and 9 for wrapping around a body member to provide pressure for controlling blood flow.
The apparatus 1 comprises a table assembly formed by a support framework 10 supporting a work table 11 having guide rails 13 and a platen 14 for receiving plastics sheets to be sealed.
The platen 14 having a handle 16 is mounted for sliding engagement with the guide rails 13 for movement in the direction of the arrows A as indicated in Figs. 1 and 2. The table 11 includes an arcuate cut-out portion 15 to facilitate operation of the apparatus 1.
A sealing press 20 comprises a sealing press support frame 25 and a sealing head 26 which is movable upwardly and downwardly in the direction of the arrows B in Fig. 1 by a ram means 27 extending between the support frame 25 and sealing head 26.
Referring in particular to Figs. 3 to 5 the sealing head 26 comprises a brass electrode 30 to which radio frequency energy is transmitted from a radio frequency energy generator 31 via a connecting strip 32 and conductor 33 which is bolted to the electrode 30. The electrode 30 is pre-heated prior to passing radio frequency energy through it by a pre-heating means which in this case comprises three spaced-apart heating plates 35 which are arranged for heat transfer to the electrode 30 and which are connected in parallel and electrically heated by electrical power supply to an electrical plug 36. The plug 36 is engageable with an electrical socket 37 carried by a bracket 38 mounted to the support frame 25. The heat transferred by the heating plates or elements 35 to the electrode 30 is controlled by a rheostat 40.
The sealing press 20 is movable by the ram means 27 from a raised inactive position illustrated in Fig. 1, with the plug 36 for the heating plates 35 engaged with the socket 37, to a lowered sealing position illustrated in Fig. 2 with the rams 27 extended and the plug 36 disengaged from the socket 37.
In use, with the sealing head 26 in the raised position illustrated in Fig. 1 the table 11 with the platen 14 is pulled outwardly into the position illustrated in Fig. 1 using the handle 16 and plastics sheets to be sealed are placed on the platen 14 in the position illustrated in dotted outline in Fig. 1. The pattern of seal applied to the plastics sheets is determined by the configuration of the sealing head defined by the sealing electrode 30 and the arrangement of the slot 17 defined in the platen 14. With the plastics sheets in position the table 11 is pushed inwardly on the guide rails 13 until the plastics sheets are positioned underneath the sealing head 26.While the sealing head 26 is in the raised position the plug 36 is engaged with the socket 37 so that electrical power flows through the heating plates 35 which pre-heat the electrode 30 to a desired temperature as determined and controlled by the setting of the rheostat 40.
When the plastics sheets are in position the rams 27 are extended pressing the sealing head 26 downwardly towards the platen 14 so that the electrode 30 engages and presses on the plastics sheets on the platen 14 in which position radio frequency energy is passed from the radio frequency generator 31 through the copper strip 32 to the conductor 33 through the electrode 30 through the plastics sheets and onto the platen 14 to earth.
The radio frequency energy excites the molecular structure of the plastics sheets to generate heat and produce a heat seal between the sheets. Because the electrode 30 is pre-heated using the heating plates the arrangement is considerably more efficient particularly with regard to usage of electrical power than known arrangements. Because of the electrode 30 is pre-heated by the heating plates 35 the maximum power from the radio frequen#cy generator 31 is applied to the radio frequency energy to excite the molecular structure of the plastics sheets and there is no power dissipation in heating the electrode 30.
The apparatus and method of the invention may be applied to the manufacture of a tourniquet cuff 6 for wrapping around a body part to provide an inflatable member that is secured to the body part and a tube is provide to allow the tourniquet to be inflated to provide pressure for controlling blood flow.
It will however be appreciated that the apparatus and method of the invention may be applied to sealing of portions of any desired arrangement of plastics sheets.
Referring to Figs. 6 to 8 there is illustrated another apparatus indicated generally by the reference numeral 50 according to the invention. The apparatus 50 is of similar construction to the apparatus 1 described above and like parts are assigned the same reference numerals. The principal difference is in the case the arrangement of the table guides 13. The pre-heating of the radio frequency electrode and other arrangements described above are substantially the same.
Many variations on the specific embodiment of the invention will be readily apparent and accordingly the invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail.

Claims (28)

1. Apparatus for sealing together portions of at least two plastics sheets comprising: a table assembly comprising a support framework and a platen mounted on the framework for receiving plastics sheets to be sealed; a sealing press having a sealing diej the press being movable relative to the platen from an inactive position, with the platen exposed for receiving plastics sheets, to a sealing position to seal portions of the plastics sheets on the platen, means for passing radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in the sealing position, and pre-heating means for pre-heating the sealing die prior to movement of the press to the active position and prior to application of radio frequency electromagnetic energy through the die.
2. Apparatus as claimed in claim 1 wherein switch means are provided to de-activate the pre-heating means when the press is moved to the sealing position.
3. Apparatus as claimed in claim 2 wherein the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moved to the sealing position.
4. Apparatus as claimed in any preceding claim wherein the apparatus includes control means for controlling the temperature to which the sealing die is heated.
5. Apparatus as claimed in claim 4 wherein the control means comprises a rheostat.
6. Apparatus as claimed in any preceding claim wherein the heating means comprises a heating plate means for heat transfer to the sealing die.
7. Apparatus as claimed in claim 6 wherein the plate means are electrically heated.
8. Apparatus as claimed in claim 6 or 7 wherein the heating plate means comprises at least two plate means spaced apart along the sealing die.
9. Apparatus as claimed in claim 8 wherein the plate means are connected in parallel.
10. Apparatus as claimed in any preceding claim wherein the table assembly includes guide means in which the platen is slidably mounted for movement into and out of alignment with the sealing press.
11. Apparatus as claimed in any preceding claim wherein the sealing press is operated by a ram means.
12, Apparatus as claimed in any preceding claim wherein the means for passing radio frequency energy from the sealing die through portions of the plastics sheets comprises a radio frequency generator, a transmitting electrode defined by the sealing die and a receiving electrode defined by the platen.
13. Apparatus as claimed in claim 12 wherein the radio frequency generator transmits radio frequency energy in the range of 27MHz.
14. Apparatus as claimed in any preceding claim wherein the sheets of plastics material form, in use, at least part of a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow.
15. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.
16. A method of sealing together portions of at least two plastics sheets using the apparatus as claimed in any of claims 1 to 15 comprising the steps of: placing the plastics sheets to be joined on a support platen, pre-heating the sealing die of a sealing press by a pre-heating means, moving the sealing die onto the plastics sheets while de-activating the pre-heating means, applying radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in a sealing position, releasing the press, and removing the sealed plastics sheets from the platen.
17. A method as claimed in claim 16 wherein the radio frequency energy is applied by a radio frequency energy generator, a transmitter electrode defined by the sealing die and a receiving electrode defined by the platen.
18. A method as claimed in claim 17 wherein the radio frequency generator transmits radio frequency energy in the range of 27MHz.
19. A method as claimed in any of claims 16 to 18 wherein the pre-heating means is de-activated by a switch means.
20. A method as claimed in claim 19 wherein the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moved to the sealing position.
21. A method as claimed in any of claims 16 to 20 wherein the pre-heating means comprises a heating plate means for heat transfer to the sealing die.
22. A method as claimed in claim 21 wherein the plate means are electrically heated.
23. A method as claimed in claim 22 wherein the heating plate means comprise at least two plate means spaced-apart along the sealing die.
24. A method as claimed in claim 23 wherein the plate means are connected in parallel.
25. A method as claimed in claim 24 wherein the table assembly includes guide means in which the platen is slidably mounted for movement into and out of alignment with the sealing press.
26. A method as claimed in any of claims 16 to 25 wherein the plastics sheets define at least part of a tourniquet cuff for wrapping around a #body member to provide pressure for controlling blood flow.
27. A method substantially as hereinbefore described with reference to the accompanying drawings.
28. A tourniquet cuff for rapping around a body member to provide pressure for controlling blood flow whenever made using an apparatus as claimed in any of Claims 1 to 14 or by a method as claimed in any of Claims 15 to 26.
28. Plastics sheets whenever sealed by an apparatus as claimed in any of claims 1 to 15 or by a method as claimed in any of claims 16 to 27.
29. A tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow whenever made using an apparatus as claimed in any of claims 1 to 15 or by a method as claimed in any of claims 15 to 27.
1. Apparatus for sealing together portions of at least two plastics sheets comprising: a table assembly comprising a support framework and a platen mounted on the framework for receiving plastics sheets to be sealed, a sealing press having a sealing die, the press being movable relative to the platen from an inactive position, with the platen exposed for receiving plastics sheets, to a sealing position to seal portions of the plastics sheets on the platen, means for passing radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in the sealing position, electrical pre-heating means for pre-heating the sealing die prior to movement of the press to the active position and prior to application of radio frequency electromagnetic energy through the die, and switch means to de-activate the pre-heating means when the press is moved to the sealing position.
2. Apparatus as claimed in Claim 1 wherein the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moved to the sealing position.
3. Apparatus as claimed in any preceding claims wherein the apparatus includes control means for controlling the temperature to which the sealing die is heated.
4. Apparatus as claimed in Claim 3 wherein the control means comprises a rheostat.
5. Apparatus as claimed in any preceding claim wherein the heating means comprises a heating plate means for heat transfer to the sealing die.
6. Apparatus as claimed in Claim 5 wherein the plate means are electrically heated.
7. Apparatus as claimed in Claim 5 or 6 wherein the heating plate means comprises at least two plate means spaced-apart along the sealing die.
8. Apparatus as claimed in Claim 7 wherein the plate means are connected in parallel.
9. Apparatus as claimed in any preceding claim wherein the table assembly includes guide means in which the platen is slidably mounted for movement into and out of alignment with the sealing press.
10. Apparatus as claimed in any preceding claim wherein the sealing press is operated by a ram means.
11. Apparatus as claimed in any preceding claim wherein the means for passing radio frequency energy from the~ sealing die through portions of the plastics sheets comprises a radio frequency generator, a transmitting electrode defined by the sealing die and a receiving electrode defined by the platen.
12. Apparatus as claimed in Claim 11 wherein the radio frequency generator transmit radio frequency energy in the range of 27 MHz.
13. Apparatus as claimed in any preceding claim wherein the sheets of plastics material form, in use, at least part of a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow.
14. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.
15. A method of sealing together portions of at least two plastics sheets using the apparatus as claimed in any of Claim 1 to 14 comprising the steps of: placing the plastics sheets to be joined on a support platen, pre-heating the sealing die of a sealing press by a pre-heating means, moving the sealing die onto the plastics sheets while de-activating the pre-heating means, applying radio frequency electromagnetic energy from the sealing die through portions of the plastics sheets to effect a seal between portions of the sheets when the press is in a sealing position, releasing the press, and removing the sealed plastics sheets from the platen.
16. A method as claimed in Claim 15 wherein the radio frequency energy is applied by a radio frequency energy generator, a transmitter electrode defined by the sealing die and a receiving electrode defined by the platen.
17. A method as claimed in Claim 16 wherein the radio frequency generator transmits radio frequency energy in the range of 27 MHz.
18. A method as claimed in any of Claims 15 to 17 wherein the pre-heating means is de-activated by a switch means.
19. A method as claimed in Claim 18 wherein the switch means comprises a plug and socket means, the plug being disengageable from the socket when the press is moved to the sealing position.
20. A method as claimed in any of Claims 15 to 19 wherein the pre-heating means comprises a heating plate means for heat transfer to the sealing die.
21. A method as claimed in Claim 20 wherein the plate means are electrically heated.
22. A method as claimed in Claim 21 wherein the heating plate means comprise at least two plate means spacedapart along the sealing die.
23. A method as claimed in'Claim 22 wherein the plate means are connected in parallel.
24. A method as claimed in Claim 23 wherein the table assembly includes guide means in which the platen is slidably mounted for movement into and out of alignment with the sealing press.
25. A method as claimed in any of Claims 15 to 24 wherein the plastics sheets define at least part of a tourniquet cuff for wrapping around a body member to provide pressure for controlling blood flow.
26. A method substantially as hereinbefore described# with reference to the accompanying drawings.
27. Plastics sheets whenever sealed by an apparatus as claimed in any of Claims 1 to 14 or by a method as claimed in any of Claims 15 to 26.
GB9011416A 1990-06-06 1990-05-22 A method and apparatus for sealing Expired - Fee Related GB2244236B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
BE9000568A BE1002186A6 (en) 1990-06-06 1990-06-06 METHOD AND APPARATUS FOR SEALING PLASTIC SHEETS.

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Publication Number Publication Date
GB9011416D0 GB9011416D0 (en) 1990-07-11
GB2244236A true GB2244236A (en) 1991-11-27
GB2244236B GB2244236B (en) 1993-10-20

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GB9011416A Expired - Fee Related GB2244236B (en) 1990-06-06 1990-05-22 A method and apparatus for sealing

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GB (1) GB2244236B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0945247A2 (en) * 1998-03-25 1999-09-29 Idemitsu Petrochemical Co., Ltd. Sealing of polyolefin-based resin, and sealed article of the resin

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB744217A (en) * 1953-05-14 1956-02-01 Transparent Package Company Improvements in or relating to the dielectric sealing of thermoplastic films
GB920228A (en) * 1960-03-01 1963-03-06 Ford Motor Co Improvements in or relating to electrode assemblies in dielectric heating apparatus
GB937755A (en) * 1959-01-07 1963-09-25 Scholl Mfg Co Ltd Improvements in or relating to heat sealed articles and method of making the same
GB959729A (en) * 1961-07-05 1964-06-03 Wasagchemie Ag Apparatus for the high frequency welding of plastic foils to form pipes
US4313776A (en) * 1978-12-14 1982-02-02 Tachikawa Spring Co., Ltd. Method of producing seat cushion member

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB744217A (en) * 1953-05-14 1956-02-01 Transparent Package Company Improvements in or relating to the dielectric sealing of thermoplastic films
GB937755A (en) * 1959-01-07 1963-09-25 Scholl Mfg Co Ltd Improvements in or relating to heat sealed articles and method of making the same
GB920228A (en) * 1960-03-01 1963-03-06 Ford Motor Co Improvements in or relating to electrode assemblies in dielectric heating apparatus
GB959729A (en) * 1961-07-05 1964-06-03 Wasagchemie Ag Apparatus for the high frequency welding of plastic foils to form pipes
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0945247A2 (en) * 1998-03-25 1999-09-29 Idemitsu Petrochemical Co., Ltd. Sealing of polyolefin-based resin, and sealed article of the resin
EP0945247A3 (en) * 1998-03-25 2001-04-11 Idemitsu Petrochemical Co., Ltd. Sealing of polyolefin-based resin, and sealed article of the resin

Also Published As

Publication number Publication date
GB2244236B (en) 1993-10-20
GB9011416D0 (en) 1990-07-11
BE1002186A6 (en) 1990-10-02

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