FR2769964A1 - METHOD AND DEVICE FOR SEALING A MOUTHPIECE OF A TUBULAR ELEMENT TO A DISC HAVING AN OPENING - Google Patents

Abstract

To make a thermoplastic joint between a mouth of a tubular element (10) and a flexible disc provided with an opening, in particular for manufacturing a waterproof protection of a dressing or plaster on a limb of a patient , a flexible disc is threaded on a conical template (22) so that the device of the disc forms an external surface to be joined, then the mouth of the tubular element is threaded on the template to adjust the mouth to the wall surface external of the disc, the template is then widened to press the wall of the disc against the mouth of the tubular element and the thermoplastic material is melted between the wall surface of the disc and the mouth of the tubular element.

Description

A8 2769964

DESCRIPTION

  The present invention relates to a method and a device for joining a mouth of a tubular element to a disc provided with an opening. The invention is particularly applicable to the manufacture of a waterproof protection for a member, as described in the specification of patent GB 9404563.0. Such limb protection comprises a watertight tubular envelope connected to a flexible disk provided with an opening. The flexible disc constitutes a tight seal to be applied against the skin of a member in front

  to be protected by means of protection.

  When manufacturing such limb protection, it is important to choose a material for the tubular envelope which retains a satisfactory shape around a limb to be protected, while being flexible and waterproof. The material of the tubular casing is relatively stiff compared to the material of the sealing disc, the disc being elastic so as to form a deformable watertight seal which satisfies the skin of the protected member. A problem therefore arises to join the mouth of the relatively stiff tubular casing to the elastic disc while ensuring that the seal is strong enough to avoid separation of the seal in use, and in

  ensuring the seal is waterproof.

  According to the present invention, a method is provided for producing a thermoplastic seal between a mouth of a tubular element and a flexible or elastic disc provided with an opening, the method comprising the steps consisting in: threading the disc on a template in order to cause at least one peripheral part of the disc to form a wall of material having an external surface to be joined, thread the mouth of the tubular element on the wall of material so as to superimpose and adjust said mouth to the external surface presented by the wall of material, widening the template in order to compress the wall of material radially outwards against the mouth of the tubular element, and applying heat in order to melt the thermoplastic material into a contact ring between the external surface of the wall of material and the mouth of the tubular element, for example in the form of a

crushed sleeve.

  The above method can also include the additional step of closing the end of the sleeve

  away from the joint with the disc provided with an opening.

  According to a feature of the invention, the step of applying heat to melt the thermoplastic material is carried out by means of a heating means which comprises a heating ring which surrounds the tubular element and the disc and against which the tubular element and disc are pressed during

  the step of widening the template.

  According to another characteristic of the invention, the step consisting in widening the template in order to press the wall of material radially outwards against the mouth of the tubular element is carried out by means of the axial compression of a ring flexible constituent

part of the template.

  Furthermore, in accordance with the present invention, there is provided a device for manufacturing a thermoplastic seal between a mouth of a tubular element and a flexible disc provided with an opening, the device comprising: a round template which comprises a body made of a flexible material, having a rim around which a peripheral part of the disc can be turned in order to form a wall of material having an external surface to be joined, the template being formed into a cone so as to allow the mouth of the the tubular member to be threaded in order to fit the external surface presented by the wall of material, means for compressing the body of material in an axial direction in order to widen the body of flexible material radially, and means for applying heat to a contact ring between the disc and the tubular member when adjusted to

disk.

  Preferably, the tubular element is made of a thermoplastic material, and the flexible disc comprises a

  thermoplastic canvas glued to it.

  Advantageously, the heating is carried out using a heating ring surrounding the tubular element and the disc while they are pressed against each other. According to an advantageous characteristic of the invention, the body of elastic material is in the form of a ring arranged between upper and lower parts of the template, the means intended to compress the body of material comprising a threaded axis intended to

  bring the upper and lower parts together.

  The invention will now be described with reference to the accompanying drawings, in which: FIG. 1 represents a limb protection which comprises a tubular envelope joined to a flexible seal by a method in accordance with the present invention. FIG. 2 represents a blank from which the tubular casing of the protection of the

Figure 1 is formed.

  3 shows a sleeve formed from the blank of Figure 2, and a disc to which the sleeve is to be joined, and Figures 4 and 5 are diagrams of the device according to the present invention for joining the

  sleeve and disc in Figure 3.

  Referring first to Figure 1, there is shown a water-tight limb protection which is of the type described generally in the specification of British Patent GB 9404563.0. The protection must be adjusted, in use, on a bandage or plaster cast on the leg or arm of a patient. The protection comprises a tubular envelope 10, forming the main body of the protection. The tubular casing is formed from a sleeve closed at one end while the other end opens in the form of a mouth 12 comprising a seal 13. The protection can be threaded onto the member of the patient, the seal being made of a flexible elastomeric waterproof material which is soft and adapts to the skin of the member. The elastomeric material can be a synthetic or natural rubber and can in particular be a polymer or a copolymer of chloroprene. Alternative materials are butyl rubbers, nitrile, a

  ethyl propylene dimonomer, or latex.

  Referring to Figure 2, the tubular casing 10 is formed from a blank 15 of the waterproof thermoplastic material which may be any synthetic polymeric material suitable for the containment of the patient's limb. The edges 16a and 16b of the blank are brought together in an overlapping relationship as shown in FIG. 3 and are welded or glued to form a sleeve 17 comprising a watertight seal 17a. The edges 16a and 16b are cut so that

  the sleeve 17 is slightly flared.

  The seal 13 is made from a disc with a central opening 14 made of an elastomeric material with a thickness of approximately 8 mm, which is pre-cut into disc form from a sheet flat. The disc 14 comprises a woven thermoplastic fabric glued to its upper surface in order to form a thermoplastic seal with the sleeve 17 in a way that

we will describe.

  Turning now to Figures 4 and 5, there is shown the device by means of which the sleeve 17 is joined to the elastomeric disc 14. The device comprises a support base 20 comprising a vertical column 21 on which is mounted a round template shown generally by the reference numeral 22. The template comprises a base part in a bowl 23 fixed to the column 21, a frustoconical upper part 24 and a deformable rubber ring 25 located between the base part 23 and the upper part 24. The deformable ring is made of an elastomeric material such as natural or synthetic rubber and is mounted on a central hub like a tire on a wheel. A threaded pin 26 passes axially through the template 22 and is coupled to the base part 23 by means of a locking washer 27

  and a threaded end nut 28.

  A compression nut 29 is screwed onto the upper part of the threaded pin 26 and can be turned by means of an operating rod 30 connected to the compression nut 29 by a tube 31 holding the compression nut 29. The rotation of the operating rod brings the compression nut into engagement with a washer 29a so

  to apply a compressive force to a support 32.

  The support 32 in turn bears on a cup washer 33. The compression force applied by the compression nut 29 via the cup washer 33 results in a downward force on the upper part 24 of the template 22. A contrary force is exerted via the axis 26 on the base part 23 of the template. The ring 25 can thus be compressed by means of the axial forces exerted by the parts of

base and upper 23 and 24.

  The material of the ring 25 is sufficiently soft that the uniform compression force applied by the base and upper parts 23 and 24 causes the ring to expand outward from the hub 35, in proportion to the compression force , while retaining the circular shape of the ring 25. It will be obvious that the compressive force applied to the ring could be generated by hydraulic or pneumatic means as an alternative to the threaded axis and to

the illustrious compression nut.

  The conical upper part 24 of the template 22 is of a shape allowing the disc 14 to be slid over the upper part 24 so as to bring an external peripheral part of the disc 14 in overlapping relation with the external edge of the ring 25 The external peripheral part of the disc 14 is therefore rotated by means of the template 22 in the form of a vertical circular wall 36. The cone of the upper part 24 of the template 22 also allows the flared sleeve 17 to be slid over the template 22. so as to bring the mouth 12 of the sleeve into covering relationship

  with the wall of material 36 formed from the disc 14.

  A heating ring 37 is provided in order to surround the deformable ring 25 and is used in order to heat an annular contact zone between the wall 36 of material and the mouth 12 of the sleeve 17. The heating ring is formed by a stainless steel, copper or brass strip approximately 0.02 cm thick so that it retains sufficient flexibility to conform to the expanding template 22 while remaining strong enough to combat the applied expansion force by the template 22. The heating ring 37 comprises a heating element mounted on its external surface and is provided with a non-stick lining such as polytetrafluoroethylene (PTE) which can be in the form of a tape applied to the surface internal of the heating ring 37. The non-stick lining allows easy removal of the heating ring 37 once a seal has been formed between the disc 14 and the sleeve 17. The heating element mounted on the ring 37 f provides enough heat to raise the temperature of the heating ring above 160 C. The heat applied to the heating ring 37 can be obtained from a source, other than an electric heating element,

  such as a gas heat source.

  In operation, a sheet of thermoplastic material is cut to form the blank 15 as shown in Figure 2 and is then welded along the joint 17a to form the flared sleeve 17 having the mouth 12. The disc 14, having been cut from a sheet of material, is presented on the template 22 and is threaded on the upper part 24 of the template 22 so as to present its layer of thermoplastic canvas woven towards the outside of the template 22. The disc is threaded on the template 22 until the external peripheral part of the disc 14 has reached a position covering the external circumference of the deformable ring 25. In this position, the material of the disc is stretched over the deformable ring 25 in order to form the circular wall 36 which is held in place

  thanks to the tension of the disc material.

  The sleeve 17 is then threaded onto the template 22 until its mouth is at the level of the circular wall 36 of the disc material. It will not slip further due to the fact that the mouth 12 is designed to be identical or slightly smaller than the diameter in combination of the template ring 22 and the disc material fitted on the ring 25. The sleeve 17 is slightly flexible and is pulled in order to extend over the disc material so that it grips the disc material firmly around the circumference of the circular wall 36. The heating ring 37 is put in place so encircle the contact area between the components to be joined, and the operating rod 30

  is turned in order to compress the deformable ring 25.

  The deformable ring 25 exerts a radial pressure towards the outside in order to crush the materials to be joined together against the internal surface of the heating ring 37. The heating element is electrically supplied in order to raise the temperature of the materials surrounded by the heating ring to a temperature above C. At this temperature, the thermoplastic material of the sleeve 17 melts inside the layer of thermoplastic fabric of the disc material in order to form a watertight seal. The supply of the heating element continues for a sufficient time to guarantee an appropriate melting of the thermoplastic materials and is then cut off by a timer. The assembly is allowed to cool, the expansion template is released by turning the operating rod 30 in the opposite direction, and the heating ring 37 is removed. The flared sleeve 17 is then removed from the template

  22, the seal being joined to its mouth.

  The wider end of the sleeve 17 is finally sealed by welding or gluing to form a closed end

  18 of the protection as shown in Figure 1.

Claims (8)

  1. A method of producing a thermoplastic seal between a mouth (12) of a tubular element (10) and an elastic disc provided with an opening (14), the method comprising the steps consisting in: threading the disc (14 ) on a template (22) in order to cause at least one peripheral part of the disc to form a wall (36) of material having an external surface to be joined, thread the mouth (12) of the tubular element (10) on the wall of material so as to superimpose and adjust said mouth (12) to the external surface presented by the wall (36) of material, widen the template (22) so as to press the wall (36) of material radially towards the outside against the mouth (12) of the tubular element (10), and apply heat in order to melt the thermoplastic material into a contact ring between the external surface of the wall (36) of material and the mouth ( 12) of the tubular element.   2. Method according to claim 1, applied to the production of a joint between a tubular element (10) and a flexible disc provided with an opening (14) in which the tubular element (10) is made of a material thermoplastic and the flexible disc (14) has a   thermoplastic canvas glued to it.   3. Method according to claim 1 or 2, applied to the production of a joint between a tubular element (10) and a disc provided with an opening (14) in which the tubular element (10) is in the form of 'a flared sleeve. 1l 4. The method of claim 3, comprising the additional step of closing the end (18) of the sleeve remote from the joint with the disc provided an opening (14).   5. Method according to any one of the claims   The foregoing, wherein the step of applying heat to melt the thermoplastic material is performed by means of a heating means which comprises a heating ring (37) which surrounds the tubular element (10) and the disc (14 ) and against which the tubular element (10) and the disc (14) are pressed during the step   consisting in widening the template (22).   6. Method according to any one of the claims   previous steps, in which the step of widening the template (22) in order to press the wall (36) of material radially outward against the mouth (12) of the tubular element (10) is carried out by means of the axial compression of a flexible ring (25) constituting a part of the template (22).   7. Device for producing a thermoplastic seal between a mouth (12) of a tubular element (10) and a flexible disc provided with an opening (14), the device comprising: a round template (22) which comprises a body (25) of elastic material having a rim over which a peripheral part of the disc can be turned in order to form a wall (36) of material having an external surface to be joined, the template (22) being formed in cone so as to allow the mouth (12) of the tubular element (10) to be threaded in order to adjust to the external surface presented by the wall (36) of material, means (26, 28, 29) for compressing the body of material in an axial direction in order to expand the body (25) of elastic material radially, and means (37) for applying heat to a contact ring between the disc (14) and the tubular element (10) when adjusted to the disc.   8. Device according to claim 7, in which the body (25) of elastic material is in the form of a ring arranged between upper (24) and lower (23) parts of the template (22), the means intended to compressing the body (25) of material comprising a threaded pin (26) intended to bring the upper parts together (24) and lower (23).