Patent Publication Number: US-2021177639-A1

Title: A splint-armored bandage and a method for its production

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application (filed under 35 § U.S.C. 371) of PCT/SE2018/051241, filed Dec. 3, 2018 of the same title, which, in turn, claims priority to Swedish Patent Application No. 1700299-9 filed Dec. 5, 2017; the contents of each of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a bandage in the form of a strip of fabric with splints attached thereto for use in fixation of an injured or temporarily disabled limb, by wrapping the splint-armored bandage in layers about the limb. The invention relates also to a method for production of a splint-armored bandage according to the invention. 
     BACKGROUND OF THE INVENTION 
     A splint-armored bandage according to the present invention can be seen as a dry alternative to a plaster bandage which needs wetting by water in order to cure and stiffen in applied position about a limb. In comparison, the dry splint-armored bandage is lightweight, time saving and less sensitive to outer conditions. 
     The splint-armored bandage of the present invention can provide a preliminary fixation of an injured or temporary disabled limb or limb joint, until a permanent fixation can be arranged at a hospital or other care unit. The splint-armored bandage of the present invention can be applied to humans or animals. 
     Produced in suitable size, the splint-armored bandage of the present invention can be wrapped into a dressing about an arm, a leg, a finger or a toe, toe and finger joints, ankles, wrists, knees and elbows, for fixation in case of fracture or other temporarily disabling injury. Although explained herein as an item for fixation of limbs or limb joints, the splint-armored bandage of the present invention may also serve for temporary fixation of other body portions, if appropriate. 
     In this connection it should be pointed out, that with respect to the occasional use, art and character of the splint-armored bandage, the present invention belongs to a category of orthopedic aids which is separated from, e.g., prosthesis, orthoses, liners and compression stockings, which are adapted for wearing on more regular basis. 
     With respect to its structure, use and functionality, the present invention can be referred to a type of orthopedic aids as represented by U.S. Pat. No. 2,957,475 A and DE 
     U.S. Pat. No. 2,329,314 A1, e.g. In both the named cases, rod-shaped substantially straight splints are prefabricated and individually inserted in pockets that are formed in a band or strip of fabric by stitching or sewing, the splints being oriented transversally, i.e. at an angle of about 90°, with respect to the longitudinal direction of the strip of fabric. 
     A prior splint-armored bandage and its manufacture is disclosed in CN 104287894 A. In this solution, polymer material splints are individually extruded and applied in situ to a fabric at intermediate angles of more than 0° and less than 90° between adjacent splints, or at angles ranging from more than 0° to less than 90° with respect to the length direction of the bandage. 
     Whether prefabricated or formed in situ, in the prior art, splint ribs are typically formed and applied individually one-by-one onto a strip of fabric in order to produce a splint-armored bandage. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a splint-armored bandage which in use provides fixation of an injured limb. 
     Another object of the present invention is to provide a splint-armored bandage that offers comfort for the wearer. 
     These objects are met in a splint-armored bandage wherein radial stiffness and circumferential contraction in a dressing about a limb are balanced so as to provide as good fixation as possible without choking or chafing the treated limb. 
     Still another object is to design a splint-armored bandage that permits implementation of an efficient and time saving method for production of the splint-armored bandage. 
     To meet with these objects the invention provides, briefly, a splint-armored bandage comprising at least one flexible splint anchored to a strip of fabric which is elastic in its length direction, the splint having the shape of a wave wherein adjacent splint ribs are interconnected at a wave crest or a wave trough respectively. 
     More precisely, a bandage for fixation of a limb is disclosed, the bandage comprising at least one flexible, thermoplastic polymer splint which is shaped and in plasticized condition attached to the surface of a longitudinal strip of fabric which is elastic in its length direction, the fabric and splint having a length sufficient for wrapping in layers about a limb. The splint is formed to the shape of waves wherein adjacent splint ribs are interconnected at wave crests and wave troughs respectively, wherein at least one of the wave crests and the wave troughs is located near, i.e. in the region of, a longitudinal edge of the strip of fabric. 
     In other words, the splint runs wave-shaped on the surface of the strip of fabric, in a plane that is parallel to the plane of the fabric. 
     An advantage and technical effect of this solution is that when dressed in layers about a wearer&#39;s limb, the splint of superimposed bandage layers forms a kind of cross-link network acting as a rigid sleeve. In this sleeve, an outer layer of fabric and splint can be wrapped tightly onto inner layers of fabric and splint without unduly increasing the circumferential contraction of the dressing about the limb, since the splint of the inner layers provide radial and circumferential stiffness to the dressing. This effect results in a firm dressing which avoids choking or chafing of the limb. 
     Embodiments of the splint include pointed, sinus-shaped, square and trapezoid wave-shapes. Each of these embodiments benefit from the technical effect of a circumferentially continuing element, which adds to rigidity in radial and circumferential directions of a dressing. 
     In one embodiment, the splint includes a continuous series of splint ribs distributed in the length direction of the bandage, adjacent ribs interconnected at wave crests and wave troughs. This embodiment provides an all-round product adapted for fixation of any kind of fracture or other injury to limbs or limb joints. 
     In one embodiment, adjacent splints in a series of splints are separated by non-armored portions of the fabric. This embodiment provides a specialized product adapted for local reduction of the pressure applied from the dressing in a region of the limb. 
     In one embodiment the splint is anchored to the fabric by being fused or bonded to fibers or threads in the fabric. This embodiment ensures attachment without need for auxiliary fastening steps or arrangements. 
     In one embodiment, the splint is sandwiched between first and second superimposed layers of fabric. This embodiment secures the splint even further to the fabric. This embodiment also provides an all-textile exterior of the dressing, avoiding the risk of the splint hooking on to external objects. 
     In embodiments of the invention, the sectional profile of the splint is formed with a width and a height, the height being a normal to the plane and surface of the strip of fabric, and a width to height ratio is the result from subjecting the splint to adjustable compression from a shaping roll when the splint is in plastic state. In some embodiments, the splint is formed with a sectional profile wherein the width to height ratio (w/h) is in the range of about 0.5/1 to about 10/1. In other embodiments, the splint is formed with a sectional profile wherein the width to height ratio (w/h) is in the range of about 1.5/1 to about 4/1. These embodiments provide, in manufacture, control of the elastic character of the splint in radial and circumferential directions of a dressing: a wider splint in the w direction will be stiffer in the plane of the fabric, whereas a splint wider in the h direction will be stiffer transversely to the plane of the fabric, 
     The objects of the invention are likewise met in a method of producing a splint-armored bandage, the method comprising: 
     heating a thermoplastic polymer material for discharge via a hot extrusion nozzle in molten or semi-molten state, 
     feeding a first strip of fabric beneath the hot extrusion nozzle, 
     forming a wave-shaped splint on the first strip of fabric by extrusion from the nozzle while moving the nozzle back and forth transversely to the feed of fabric, this way forming a series of splint ribs distributed in the length direction of the strip of fabric and interconnected at their ends by wave crests and wave troughs respectively, and 
     positioning at least one of the wave crests and the wave troughs near, i.e. in the region of, a longitudinal edge of the strip of fabric. 
     The benefits of this method are that splints are shaped and anchored to a strip of fabric in one singular step of production, this way avoiding the preparatory and subsequent work which has hitherto been required by most prior art solutions in splint armored bandages. 
     An additional step in the method comprises subjecting the splint to adjustable compression when the splint is passed under a shaping roll in plastic state. The sectional profile of the splint is this way controlled by pressure adjustment to achieve a width to height ratio in the range of about 0.5/1 to about 10/1, preferably to achieve a width to height ratio in the range of about 1.5/1 to about 4/1. 
     The benefits and technical effects of this manufacturing step are as previously explained. 
     Other details of the manufacturing method comprise: 
     solidification of the splint by feeding the strip of fabric through a cooling region, 
     use of a thermosetting, petroleum or cellulose based polymer, with a melting point temperature in the range of 60° to 300° C, and which remains flexible and elastic at temperatures of −20° C. or lower, 
     use of an elastic fabric web including synthetic or natural fibers, or a mixture or composition thereof, the fabric having a tacky surface, 
     applying a second strip of fabric onto the first strip of fabric and splint, 
     applying an adhesive to an exposed side of the first or second strip of fabric, wherein the adhesive is chosen to provide adhesion between overlapping layers of fabric, 
     These and other embodiments of the invention, as well as advantages and technical effects provided by the invention, will also be discussed below in the detailed description and with reference made to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  is a schematic setup of a production line for the manufacture of a splint-armored bandage according to embodiments of the present invention, 
         FIG. 2  is a cut-out detail and sectional view of the production line of  FIG. 1  shown on a larger scale, 
         FIG. 3  shows a first embodiment of a splint for the splint-armored bandage, 
         FIG. 4  shows the first embodiment of the splint in modified design, 
         FIG. 5  shows the splint of the first embodiment expanded in longitudinal direction, 
         FIG. 6  is a schematic representation of overlapping layers of splint-armored bandage, 
         FIG. 7  is an elevation view showing the splint-armored bandage of the present invention dressed about a human foot and ankle, 
         FIG. 8  shows an alternative splint design, 
         FIG. 9  shows another alternative splint design, 
         FIG. 10  shows yet another design of the splint, 
         FIG. 11  shows an alternative application of splints, and 
         FIG. 12  shows yet an alternative design of the splint-armored bandage. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     With reference to  FIG. 1 , a production line for the manufacture of a splint-armored bandage by application of a splint to a longitudinal strip of fabric comprises a hot extrusion station  1  and a fabric feeding path  2 . 
     The hot extrusion station  1  includes a container  3  for a thermoplastic polymer material, equipped with a heater  4  and a hot extrusion nozzle  5 . One or more additional heaters  4 ′ may be installed along the fabric path  2  in order to maintain or return the splint into plastic state. 
     The hot extrusion nozzle  5  is suspended movable above the fabric feeding path  2  and controlled in back and forth movements, transversely to the fabric feeding path  2 , by means of a nozzle control  6 . Nozzle control also involves controlling the discharge rate of polymer product via the nozzle, The specification of components in the hot extrusion station  1  may correspond generally to those conventionally applied in extrusion of polymer and co-polymer materials. 
     The fabric feeding path  2  defines a feed direction F from a fabric supply reel  7  to a reel  8  for a splint-armored fabric. The reel  8  is driven for feeding, continuously or intermittently as the case may be, a strip of fabric  9  from the supply reel  7  to pass underneath the nozzle  5  from which a string of molten or semi-molten polymer product  10  is discharged so as to form a splint  10  on the fabric. The path length from the nozzle  5  to the reel  8  is long enough to permit cooling and solidification of the splint, until the fabric with splint is rolled onto the reel  8 . For the purpose of accelerating solidification, the fabric feeding path  2  may include a cooling region  11  through which the fabric and splint passes before it reaches the reel  8 . The cooling region may include a cooling fan, or a cooling plate  12 , e.g., over which the fabric and splint is passed in the feed direction F. 
     A fabric suitable for production of a splint-armored bandage according to the present invention can be comprised of synthetic fibers or natural fibers, or a mix or composition of synthetic and natural fibers. A composite fiber may include a cotton fiber or thread coated with an elastomeric compound, e.g. The fibers may be formed into threads that are woven, knitted or interlaced to produce the fabric. At least the warp or yarn of the fabric is elastic. The elasticity may result from intrinsic properties in a synthetic, composite or rubber thread, and may alternatively be the result of appropriate knitting or weaving technique. 
     A suitable fabric is a fabric comprising fibers or threads that provide a tacky effect. The character of tackiness which is aimed for results in self-adhesion between superimposed layers of fabric in a dressing about a limb. Fabric which meets the desired tackiness and elasticity can be found commercially, such as the brands of fabric which are conventionally used in adhesive bandages and wound dressings. 
     A polymer suitable for production of a splint-armored bandage according to the present invention is a thermoplastic or thermosetting polymer with a melting point temperature that is well above the upper temperatures prevailing in normal use of the bandage. At the other end of the scale, the temperature of the polymer splint in molten or semi-molten state must not deform or damage the fibers or threads in the fabric. Particular attention should be paid to specifications, such as melting point temperature, for synthetic fibers included in the fabric. It is also essential that the splint material stays flexible, i.e. does not become brittle, at the lower temperatures prevailing in normal use of the bandage. A thermoplastic or thermosetting polymer which has a melting point temperature within a range of 60° to 300° C., and which remains flexible and elastic at temperatures of −20° C. or lower, is considered to meet the purpose for a wide range of embodiments. 
     Without excluding other alternatives, a splint material according to specifications may be found among, e.g., polyethylene, polypropylene, polyvinyl chloride, polyamide, or among thermoplastic cellulose derivatives such as cellulose acetate e.g., with or without plasticizer added to the polymer composition. 
     The manufacturing process can include a pelletized or granulated polymer material which is heated to melting temperature for discharge via the nozzle  5 . 
     Alternatively, the manufacturing process can include discharge of a solid polymer thread  13  (see  FIG. 1 ) which is heated to a temperature below melting temperature (semi-molten) at which the thread can be plastically deformed and its applied shape on the fabric be maintained after cooling. In one embodiment, the splint is shaped from a solid polymer thread, such as a polyamide or nylon thread, with a 
     homogenous section and a diameter of about 0.5-10 mm. However, whether starting from a pelletized material or a thread, in either alternative the splint can be shaped and applied to the strip of fabric in a plasticized condition, and in solidified state attaching to the threads and/or fibers in the fabric, without requiring special preparation or modification of the fabric. 
     It shall be noted that the shape and dimensions of the splint can be varied through proper control of fabric feed rate and polymer discharge rate at the hot extrusion nozzle  5 . With reference to  FIG. 2 , which is a cut-out detail and sectional view of the production line of  FIG. 1  shown on a larger scale, a transverse section of a splint  10  is formed with a width w and a height h, the height h being a normal to the plane and surface S of the strip of fabric. 
     The width to height ratio in the sectional profile of the splint  10  is the result from subjecting the splint to a controlled compression applied in a compression region  14 , arranged in the production line (see  FIG. 1 ) at a position where the splint  10  is still in plastic state. The compression region comprises a shaping roll  15  under which the fabric and splint is passed in the feed direction. By adjustment of the pressure applied from the shaping roll  15  there is accomplished control of stiffness of the splint in the directions w and h. That is, a wider splint in the w direction will be stiffer in the longitudinal plane of the fabric (i.e., in the circumferential direction of a dressing about a limb), whereas a splint wider in the h direction will be stiffer transversely to the plane of the fabric (i.e. in radial direction of a dressing about a limb). 
     According to this aspect of the present invention, and more precisely by properly adjusting the height of a gap between the shaping roll  15  and the fabric  9 , the section of the splint  10  can be formed with various w/h ratios, 
     It is possible and lies within the scope of the invention to arrange the mouth of the nozzle  5  such that a polymer string is deposited onto the fabric, wherein the width w of the splint section is less than the height h of the splint section. This can be achieved, for example, using a rectangular nozzle mouth which is tilted at an angle of about 45° from the plane of the fabric. The w/h ratio may this way be extended to a lower range limit of about 0.5/1, at least. An upper range limit, up to which the splint will still provide adequate radial support in a dressing, is for this practical reason defined at a w/h ratio of about 10/1. 
     The applicant has found that a width to height ratio within the range of about 1.5/1 to about 4/1 provides a most beneficiary balance between elasticity and radial and circumferential rigidity in a dressing, and is therefore preferred in a bandage which is armored by means of a wave-shaped polymer splint. 
     One embodiment of a splint-armored bandage produced in a production line substantially as recited above is shown in  FIG. 3 . In this embodiment, the splint  10  includes a continuous series of splint ribs  16  and  17  distributed in the length direction L of the strip of fabric  9 , and interconnected at their ends by wave crests  18  and wave troughs  19  respectively. 
     More precisely, a discrete length of the splint-armored bandage may include one singular wave-shaped splint  10  extended the full length of the bandage, as illustrated in  FIG. 3 . 
     In one embodiment, a splint-armored bandage may include a series of splints  10  of shorter lengths, wherein adjacent splints are separated in the longitudinal direction L by a non-armored length  20  of the bandage, as illustrated in  FIG. 4 . 
     In particular, the shortest wave-forming element wl available in a splint-armored bandage according to the present invention is one wavelength long, including a pair of adjacent splint ribs  16  and  17 , in one of their ends interconnected by a wave crest  18  or a wave trough  19  respectively. 
     With reference to  FIG. 5  a splint  10 , whether produced in a petroleum based or cellulose based thermoplastic polymer, provides in solidified state a flexible and elastic armor that follows in elongation E and contraction C of the fabric which is elastic in its length direction L. The elastic connection between adjacent splint ribs, i.e. at wave crests and wave troughs, results in a splint acting like a tension spring element which operates in the length direction of the fabric, permitting elongation and adding to contraction of the fabric from an expanded state, 
     In a splint-armored bandage according to the present invention, the strip of fabric  9  and the splint  10  have a length L sufficient for wrapping in layers about a limb. Without limiting the invention to a specified length, but rather to indicate the art and character of the subject of the present invention, a length L in the range of 0.5 to 10 meters is considered to cover most practical cases. If appropriate, a length of fabric in one or both ends of the fabric may be left without the splint in order to facilitate the foundation and/or finishing of a dressing about a limb. Excessive lengths of the splint-armored bandage can be cut off from a dressing by using knife or scissors 
     The strip of fabric  9  may be formed with transverse widths in the order of about 10 mm up to the order of about 400 mm, covering various needs for fixation of body portions the size of an upper body down to finger size. 
     In one embodiment of the present invention, the splint ribs are formed with a w/h ratio which differs from the w/h ratios of the splint waves or the splint crests. For example, by applying pressure only in the longitudinal edge regions of the splint-armored fabric, the wave crests  18  and/or the wave troughs  19  can be flattened to a higher w/h ratio, such as 1.5/1 or higher, whereas the splint ribs  16  and  17  are left at a comparatively lower w/h ratio, such as 0.5/1 or higher. This way, elasticity in the length direction of the splint-armored fabric can be altered without affecting the radial stiffness transversally to the fabric. 
     The frequency of waves in a dressing, and thus the density of armor, can also be adjusted and adopted to need and anatomy in the treated limb by more or less stretching of fabric and splint. 
     With reference to  FIG. 6 , the radial and circumferential rigidity in a dressing can also be enhanced locally by arranging crossing splints in overlapping layers of fabric, such as at the location of a suspected fracture, e.g. 
       FIG. 7  shows the splint-armored bandage of  FIGS. 3-6  dressed about a human ankle. From the drawing of  FIG. 7  it can be appreciated that in applied state the splint-armored bandage forms an overlapping and crosslinked network of splints that provide all-around support, in appearance similar to scales in the panzer of a fish or reptile. Yet, the armor is still flexible to avoid discomfort caused by pressure or chafing, and permits adaptation to protrusions on the limb, such as heel and fibula e.g., which can be positioned between splint ribs  16 ,  17 . 
     In the manufacturing process, feeding the strip of fabric as well as nozzle movement and polymer discharge rate may be controlled for continuous or intermittent operation. Different splint shapes and patterns can this way be formed onto the fabric. 
     A sample of splint shapes and embodiments made available by the present invention are illustrated in  FIGS. 8-11 . In  FIG. 8  the splint has a pointed wave shape, whereas in  FIG. 9  the wave shape is sinusoidal.  FIG. 10  illustrates a splint having the shape of a square or trapezoidal wave. With respect to its shape, a common feature of disclosed embodiments is that the splint is shaped as a wave extended in a plane parallel to the plane of the fabric, the splint changing its run direction, uninterrupted, in a wave crest or a wave trough respectively. 
     The manufacturing process can be modified. For example, the feed direction of the fabric may be reversed in a process of applying one or more additional splints. In a set of splints, the splints may be arranged to run in parallel side-by-side while displaced laterally in the width direction of the strip of fabric, or the splints can be arranged intersecting each other. Alternatively, two or more hot extrusion stations may be arranged in succession in the production line to produce parallel or intersecting splint patterns, such as the one illustrated in  FIG. 1 , e.g. 
     The distribution of the splint  10  extends generally in longitudinal direction of the strip of fabric, the wave crests and troughs located near the longitudinal margins M of the strip of fabric (see  FIG. 12 ). 
     However, the transverse width or amplitude of the splint need not cover the full width of the strip of fabric: in fact, a portion N of the width of the fabric may be left without armor in the length of the fabric, substantially as illustrated in  FIG. 12 . Although not illustrated in the drawings, it will be understood that the splint or splints may alternatively be centered on the strip of fabric, leaving unarmored corridors along both edges of the fabric. Preferably though, at least one of the wave crests and the wave troughs is located near, i.e. in the region of, a longitudinal edge M of the strip of fabric as illustrated in  FIG. 12 . 
     It serves to be noted, still with reference to  FIG. 12 , that the inclinations a, b of the splint ribs  16  and  17  with respect to the longitudinal direction of the strip of fabric  9  need not be the same for the full length of the strip of fabric. By adjusting the feeding speed of the fabric and/or speed of movements of the hot extrusion nozzle, the ribs  16 ,  17  following each other in succession may be given different inclinations with respect to the fabric longitudinal direction. By varying the inclination of splint ribs there is achieved a possibility of concentrating the stabilizing forces in a desired direction in a bandage dressing. This feature can be of advantage, e.g., in the fixation of a joint at an angle between upper and lower limb portions. 
     In a splint-armored bandage produced and composed substantially as described above, the splint may be anchored to the fabric through bonding at the interface between the splint and the fabric. In this context,“bonding” is used as a definition of a connection between splint and fabric that arises upon solidification of splint material which in molten or semi-molten phase has adhered to threads or fibers in the fabric. Bonding can also comprise penetration of molten splint material into and/or between threads or fibers in the fabric. If appropriate, bonding may also include fusion between the splint material and any synthetic component in the fabric. Bonding between splint and fabric can be enhanced when splint material is forced into the fabric during the step of compressing the splint while in plastic state as mentioned above. 
     However, a splint may be anchored and affixed to the fabric in other ways beside bonding. 
     With reference again to  FIG. 1 , finishing of the splint-armored bandage optionally involves application of an additional second strip of fabric  9 ′ which is arranged superimposed on the first strip of fabric and splint. The second strip of fabric can be introduced in the fabric feeding path  2  at a position downstream of the shaping roll  15  as illustrated, or at a position (not illustrated) upstream of the shaping roll  15 . 
     The resulting bandage forms a laminate wherein the splint is anchored in the bandage by being sandwiched between layers of fabric. 
     The layers of fabric may be secured to each other simply through the adhesion between tacky fabric surfaces being laid or pressed together. Alternatively, or in addition thereto, stitches of thread may be applied through the layers of fabric. 
     Stitching may also serve for fixation of the splint in a laminate of superimposed layers of fabric. Other alternatives include application of heat and/or pressure to achieve connection between the layers of fabric. If appropriate, a lamination station (not shown in the drawings) performing sewing, heating or compression may be included in the production line of  FIG. 1 . 
     Beside the embodiments presented above, the invention can be modified and realized in other ways without abandoning the scope of the invention. 
     One modification of the invention comprises an additional step in the production process, wherein an external layer, or string, of adhesive is applied to the outer and exposed side of the second strip of fabric  9 ′. The purpose of the added adhesive layer is to improve adhesion between overlapping layers of fabric, this way even further increasing the integrity of a dressing applied to a limb. With reference again to  FIG. 1 , the laminate of the first and second fabric with the splint positioned there -between can be fed through an adhesive transfer station  21 , comprising an adhesive transfer roll or an adhesive spray curtain, e.g. At a position downstream of the location of the station  21 , the laminate can be arranged to receive a protective film or paper  22  before the finished product is wound onto the reel  8 . 
     It will be realized that a splint of wave-shape may alternatively be prefabricated in a heat extrusion process and stored on a reel. A splint of wave-shape may also alternatively be prefabricated from a sheet of material by punching, or even produced from a solid thread that is bent into wave-shape. The prefabricated splint is then, in solid state, rolled off onto a strip of fabric moving down the fabric feeding path. By heating the splint to thermoforming temperature the splint is set in plastic state, its sectional profile shaped and bonded to the fabric by application of pressure from a shaping roll as previously explained. 
     Accompanying claims define the invention as described and explained, including disclosed embodiments and others which would be readily derivable from the disclosure although not explicitly illustrated and specified herein.