Surgery: splint – brace – or bandage – Bandage structure – Support covering
Reexamination Certificate
2000-06-30
2002-08-13
Lewis, Kim M. (Department: 3761)
Surgery: splint, brace, or bandage
Bandage structure
Support covering
C602S076000
Reexamination Certificate
active
06432074
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to deformable articles particularly to extensibly deformable articles and to methods for assessing the degree of deformation of such articles visually.
BACKGROUND OF THE INVENTION
For many deformable articles, for example extensible articles it is desirable to be able to assess when a pre-determined degree of extension has been achieved. For example it may be desirable to know when a particular material has been extended to a value which is close to its elastic limit in order to avoid exceeding said limit. Such methods are useful in many areas where either an article's extension or the compression or tension it transfers to another object must be known, and where instrumentation is impractical.
In the field of medicine, extensible fabrics are often used in dressings and bandages and if these are applied too tightly to a patient, problems may result due to the high pressure applied. In extreme cases blood flow can be severely impaired and damage to body tissues can result.
For example compression bandages are used primarily in the treatment of leg ulcers where venous insufficiency is a major factor. The compressive forces promote good valve performance in the veins leading to more efficient blood circulation and thus better healing.
However the main perceived difficulty for users of compression bandages is ensuring that enough pressure is applied to a limb to achieve therapeutic benefit without over-tightening the bandage. This often results in under tightening thus greatly reducing any therapeutic benefits.
It is known that figures on the surface of a bandage may act as an indication of the amount of tension. Such a device is disclosed in U.S. Pat. No. 3,613,679.
U.S. Pat. No. 4,133,307 discloses a device where the elastic strip runs within a non-extensible, partly transparent tube where both the strip and tube have markers which when aligned give an indication of the amount of tension.
There is thus a need to provide an effective and convenient way of determining when an extensible article has been extended to a particular degree.
SUMMARY OF THE INVENTION
Therefore in accordance with the present invention there is provided an extension indicator comprising first and second cooperating members, each being adapted to be secured to an extensibly deformable article, in which one of said members is more extensible than the other and in which each member bears visual indication means which upon extension of the more extensible member are adapted to align with each other to indicate a predetermined extension of the more extensible member.
The invention further provides an article comprising an extensible material and including an extension indicator in accordance with the invention and as herein described.
By ‘extensible’ is meant the ability of the member to be stretched without breaking.
According to a first embodiment of the invention there is provided an extension indicator including at least a first member comprising a transparent extensible layer with a first image present and a second member comprising a layer with a second image present and where the first layer overlays the second layer and the first layer can extend independently relative to the second layer.
Transparency is defined as being able to see through easily and distinctly. Transparency may be achieved by using a transparent material or by cutting slits or holes into an opaque material.
The first and second layers may be connected in such a way that the connection does not impede relative extension of the layers. For example the first layer and the second layer may be connected along a line perpendicular to the axis of extension. Alternatively the first and second layer may be independently bonded to a substrate with no direct connection between layers.
For use as an extension indicator as hereinbefore described the first layer is allowed to extend with respect to the second layer. The images visible on or through the layers change position with relative extension between the layers to indicate extension. On reaching the correct extension the images come into a recognizable alignment, for example the images overlap to give a single image or a single image is positioned between two images.
In one aspect of this first embodiment of the present invention there is provided an extension indicator comprising at least a first transparent extensible layer with a first image present and a second layer with a second image present and a third extendible layer where the first and third layer encapsulate the second layer, and the first layer can extend independently relative to the second layer.
The indicator is aptly at least 0.1 cm long and may be at least 5 cm long (when measured along the length of the indicator prior to the stretching of the fabric). Stretching of the article to a pre-determined extent may cause the indicator to extend for example by at least 10, 50, 100 or 200% for example.
According to a second embodiment of the present invention there is provided an extension indicator comprising at least a first layer wherein the layer contains a slit in the direction of extension, markings on opposite sides and adjacent to the slit and a region of variable elasticity on at least one side of the slit.
For use as an extension indicator as hereinbefore described the indicator is extended and due to the region of variable elasticity on at least one side of the slit, the markings on each side move relative to each other. The correct extension is indicated when the markings line up in a predetermined manner.
Elasticity is the extent to which a material stretches under a given tension.
The extension indicator may comprise at least a first layer where the layer contains a slit in the direction of extension, markings on opposite sides and adjacent to the slit and a region of variable elasticity on at least one side of the slit.
Alternatively the extension indicator may be part of an extensible article in that the article contains a slit in the direction of extension and at least two markings on opposite sides and adjacent to the slit and a region of variable elasticity on at least one side of the slit.
According to a third embodiment of the present invention there is provided an extension indicator comprising at least a first member, for example a layer of material overlaying a second member, for example a second layer of a material wherein the first layer includes an extensible shape with a perforation and the second layer includes an image bearing surface.
For use as an extension indicator in this embodiment of the invention the first layer and the second layer with an image bearing surface are allowed to extend with respect to each other. The image visible through the perforation in the first layer changes with relative extension between the layers to indicate extension. This is achieved by the first layer having a different elasticity to the second layer.
Preferably the first layer has a modulus of elasticity that varies along its length. This can be achieved by having a first layer with a non-uniform shape, for example, a triangle. If a triangle is anchored only at its ends, an applied tension that stretches the triangle will extend the triangle more at the thin end (a single vertex) than at the thick end (a double vertex). Thus when the triangle is fixed to an image bearing surface and the surface is extended, there will be relative movement between the triangle and the surface, thus changing the image visible through a perforation, for example a hole in the triangle.
Preferably the extension indicator comprises a first layer comprising a triangular piece of fabric with a perforation at one end fixed to an image bearing surface. Extension is to be indicated along a longitudinal axis of the image bearing surface. The triangle is fixed to the surface along one edge on a lateral axis, with the perforation in a corner at a point furthest from the fixed edge. The comer is also fixed to the surface. The image bearing surface is provided with markings, the relative po
Ager Colin
Colby Edward
Jones Tim
Naiman Alaric
Priest Mark
Larson & Taylor PLC
Lewis Kim M.
Smith & Nephew plc
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