Patent Publication Number: US-6705070-B2

Title: Method of making furniture with synthetic woven material

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of copending U.S. patent application Ser. No. 10/062,905, filed Jan. 31, 2002, entitled “Method of Making Furniture With Synthetic Woven Material” which claims the benefit of U.S. Provisional Application No. 60/336,819, filed Dec. 5, 2001, the disclosures of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates in general to the field of furniture constructed with synthetic woven material, and more particularly, to methods of stabilizing synthetic yarns of multiple filaments such as twisted yarns and woven synthetic yarn material using heat treatment during the manufacturing process. 
     Natural wicker has been used in the manufacture of furniture, baskets and other articles for many centuries. Natural wicker articles are manufactured from the twigs or branches of various plants that are first soaked in water in order to make them pliable, then woven to form into the article and finally allowed to dry. Furniture manufactured from wicker offers greater comfort than furniture manufactured from some other materials because of wicker&#39;s inherent compliancy. Further, wicker is light weight and reasonably strong, making it an important material in the manufacture of furniture. 
     The popularity of wicker furniture has increased significantly. The casual, informal appearance of wicker has made it especially popular for use in enclosed porches and other informal settings in homes, hotels and other establishments. Natural wicker, however, has had limited use in the outdoor furniture market, including patio furniture, pool furniture and the like. This is because natural wicker softens and weakens when wet, and is more susceptible to rotting and mildew than many other natural and man-made furniture materials. 
     Woven wicker typically comprises a warp yarn, i.e., a yarn running straight through the woven material and providing support, and a weft yarn, i.e., a yarn used as filler that is woven around the warp yarn. Numerous styles of weave are used in the manufacture of wicker furniture. The various styles of weave result in a different look, feel, strength and weight of the finished woven product. In a simple weave pattern, the warp yarns are spaced apart and arranged parallel to each other. The weft yarns are woven over and under alternating warp yarns. Adjacent weft yarns pass on opposite sides of a given warp yarn. Variations of this pattern, such as passing the weft yarn over two adjacent warp yarns, are known in the art. 
     Polymer yarns have also been used to manufacture wicker-like furniture. By way of example, a polymer yarn is known which is constructed as an elongated body, such as of indeterminate length, having a core surrounded by a polyvinylchloride (PVC) outer coating, for example, foamed PVC material which gives greater volume with less material. The outer coating may be formed of other synthetic materials such as polyamides, polyesters and the like. The yarn is typically made in a single step using a coextrusion process, as is known in the art. The inner core may include a single filament of polyester, or may include a plurality of polyester filaments bundled to form a single core. In addition, the core may be formed of other materials than polyester, monofilament or stranded, such as polyamides and the like. The core is designed to give the yarn greater mechanical strength over yarns formed only of polymer material. 
     The polymer yarn being constructed from foamed PVC material results in a lack of uniformity in the foaming of the PVC material during the extrusion process. This produces a yarn which lacks a uniform cylindrical appearance. Specifically, the outer surface of the yarn is deformed, such as by having undulations, mounds and/or depressed areas along the length of the yarn. The deformed shape of the outer surface of the yarn results in the yarn having a more natural look to that of real wicker. It is also known to provide the exterior surface of the polymer yarn with one or more random stripes of a contrasting color and/or one or more random grooves. The stripes and grooves can be continuous and/or intermittent along the exterior surface of the yarn. The yarn, however, can also have a more uniform cylindrical shape, as well as other shapes such as square, oval, triangular and the like. Polymer yarns as thus far described are known from U.S. Pat. Nos. 5,704,690; 5,845,970; and 6,179,382, as well as U.S. Design Pat. Nos. 395,171; and 409,001, the disclosures of which are incorporated herein by reference. 
     As in the case of natural wicker, polymer yarns have been woven into a woven material which has been used in the manufacture of casual furniture suitable for the outdoor furniture market, including patio furniture, as well as for indoor use. Due to the nature of polymer yarns, it has been known to subject the woven material to a heat setting process prior to attaching the woven material to the frame forming the finished article of furniture. In this regard, a section of the woven material would be placed in an oven at an elevated temperature to cause the polymer material to soften whereby contiguous portions of the yarn would bond together stabilizing the shape of the woven material. The heat set woven material would be subsequently attached to the skeletal frame of an article of furniture to form, for example, a seat portion, a back rest portion or the like. 
     Heat setting the woven material renders the material less flexible, and therefore, more difficult to conform and attach to the skeletal frame of an article of furniture. In addition, certain components of the furniture article are only wrapped with a continuous strand of polymer yarn without forming a weave. As this wrapped portion is not subject to a heat setting process, it is possible that the wrapping will loosen during use of the furniture article. 
     It is therefore desirable to provide improvements in the manufacture of furniture articles including the use of polymer yarns and woven material therefrom, and more particularly, to a heat setting process which overcomes the disadvantages noted with respect to the aforementioned furniture articles. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention there is described a method of making a twisted elongated yarn of indeterminate length, the method comprising providing a first elongated yarn of polymer material of indeterminate length, providing a second elongated yarn of polymer material of indeterminate length, heating at least one of the first and second elongated yarns to a predetermined temperature, and continually twisting the first and second elongated yarns together to form a twisted yarn therefrom, wherein the temperature is sufficient to cause the first and second elongated yarns to adhere to each other. 
     In accordance with another embodiment of the present invention there is described a heat set twisted elongated yarn comprising a first elongated yarn of polymer material twisted together with a second elongated yarn of polymer material, at least one of the first and second elongated yarns being heated to a sufficient temperature prior to being twisted together whereby the first and second elongated yarns are adhered to each other. 
     In accordance with another embodiment of the present invention there is described a method of making an article of furniture, the method comprising providing a frame having the shape of an article of furniture, weaving first and second elongated strands of polymer material into a woven portion attached to the frame to provide the article of furniture, and heat setting the woven portion of polymer material by heating the article of furniture to a temperature sufficient to cause the first and second elongated strands to adhere to each other. 
     In accordance with one embodiment of the present invention there is described a method of making a twisted elongated yarn, the method comprising providing a first elongated yarn of polymer material of indeterminate length, providing a second elongated yarn of polymer material of indeterminate length, heating at least one of the first and second elongated yarns to a predetermined temperature, and continually twisting the first and second elongated yarns together to form a twisted yarn therefrom, wherein the temperature is sufficient to cause the first and second elongated yarns to adhere to each other. 
     In accordance with another embodiment of the present invention there is described a heat set twisted elongated yarn comprising a first elongated yarn of polymer material twisted together with a second elongated yarn of polymer material, at least one of the first and second elongated yarns having been heated to a sufficient temperature whereby the first and second elongated yarns are adhered to each other. 
     In accordance with another embodiment of the present invention there is described a method of making an article of furniture, the method comprising providing a frame having the shape of an article of furniture, weaving first and second elongated strands of polymer material into a woven portion attached to the frame to provide the article of furniture, and heat setting the woven portion of polymer material by heating the article of furniture to a temperature sufficient to cause the first and second elongated strands to adhere to each other. 
     In accordance with another embodiment of the present invention there is described an article of furniture made by providing a frame having the shape of an article of furniture, weaving first and second elongated strands of polymer material into a woven portion attached to the frame to provide the article of furniture, and heat setting the woven portion of polymer material by heating the article of furniture to a temperature sufficient to cause the first and second elongated strands to adhere to each other. 
     In accordance with another embodiment of the present invention there is described a method of making a twisted elongated yarn, the method comprising providing a first elongated yarn of polymer material of indeterminate length, providing a second elongated yarn of polymer material of indeterminate length, at least one of the first and second elongated yarns having a predetermined temperature, and continually twisting the first and second elongated yarns together to form a composite yarn therefrom having a twisted shape, wherein the temperature is sufficient to cause the composite yarn to retain its twisted shape without the first and second elongated yarns adhering to each other. 
     In accordance with another embodiment of the present invention there is described a heat set twisted elongated yarn comprising a first elongated yarn of polymer material twisted together with a second elongated yarn of polymer material forming a composite yarn having a twisted shape, at least one of the first and second elongated yarns having been heated to a sufficient temperature whereby the composite yarn retains its twisted shape without the first and second elongated yarns adhering to each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above description, as well as further objects, features and advantages of the present invention will be more fully understood with reference to the following detailed description of a method of making furniture with synthetic woven material, when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is top plan view of a portion of a heat set twisted polymer yarn constructed in accordance with one embodiment of the present invention; 
     FIG. 2 is a diagrammatic illustration showing the fabrication process of heat setting the twisted polymer yarn as shown in FIG. 1; 
     FIG. 3 is a perspective view of a skeletal frame of an article of furniture; 
     FIG. 4 is a top plan view of woven material constructed by weaving the polymer yarn as shown in FIG. 1 in accordance with one embodiment of the present invention; and 
     FIG. 5 is a perspective view of an article of furniture in the nature of a chair to which there is attached the woven material as shown in FIG.  4  and components wrapped with the twisted polymer yarn as shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     In describing the preferred embodiments of the subject matter illustrated and to be described with respect to the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and is to be understood that each specific term includes all technical equivalence which operate in a similar manner to accomplish a similar purpose. 
     Referring to the drawings, wherein like reference numerals represent like elements, there is shown in FIG. 1 in accordance with one embodiment of the present invention a twisted yarn of indeterminate length designated generally by reference numeral  100  which has been heat set in accordance with the present invention. The twisted yarn  100  is made of two strands or filaments  102 ,  104  of polymer material of the type and construction as described in the aforementioned patents which have been incorporated herein by reference. However, other strands or filaments of polymer material of a different construction or polymer material are also contemplated for use in producing a twisted yarn  100  or a weave of woven material in accordance with the present invention. Although the twisted yarn  100  has been illustrated as comprising two strands  102 ,  104 , it is to be understood that the twisted yarn can be constructed from greater than two strands if so desired. In addition, it is not required that the strands  102 ,  104  be identical in size, shape and/or surface configuration. 
     Referring now to FIG. 2, there will be described the process of manufacturing a heat set twisted yarn  100  in accordance with one embodiment of the present invention. As shown, there is provided a source  106  of a continuous length of a strand  102  of polymer material. A similar source  108  is provided for a continuous length of another strand  104  of polymer material. Generally, the sources  106 ,  108  will be in the nature of a spool of an indeterminate length of the strands  102 ,  104  of the polymer material. 
     The individual strands  102 ,  104  are fed concurrently from the spools into an oven  110  which is heated to a predetermined temperature. In the case of PVC material, an oven temperature of about 270° F. has been found suitable for use in accordance with the present invention. The temperature of the oven  110  will take into consideration the type of the polymer material forming the strands  102 ,  104 , as well as the linear rate in which the strands pass through the oven, for example, the residence time in the oven. Based upon the oven temperature and residence time of the strands  102 ,  104  within the oven  110 , at least the outer surface of the strands will reach about their softening temperature. Accordingly, lower temperatures with longer residence times and higher temperatures with shorter residence times are contemplated. It is preferable that the temperature of the strands  102 ,  104  do not reach their melting temperature where they would lose their general shape. However, a slight melting of the outer surface region of the strands  102 ,  104  is contemplated within the scope of the present invention. Although the invention has been described as heating both of the strands  102 ,  104 , it is contemplated to adhere the strands together by heating only one of the strands. The other strand may be at room temperature or heated to a temperature less than its softening temperature. 
     It can be appreciated that the temperature of the oven will vary according to the particular polymer material forming the strands  102 ,  104 , as well as the residence time for the strands within the oven. For polymer material most suitable for use in accordance with the present invention, a temperature range of 200 to 375° F., and more preferably about 250 to 300° F. is contemplated. However, as the basis for determining the oven temperature and residence time have been described herein, it is to be understood that other temperatures can be selected for suitable use with any polymer material in which to form a twisted yarn from strands  102 ,  104 . 
     As the heated strands  102 ,  104  exit the oven  110 , they pass through a conventional filament twisting apparatus  112 . The twisting apparatus  112  is operative for twisting the two strands  102 ,  104  together to form the twisted yarn  100  as best shown in FIG.  1 . The twisting apparatus  112  may be of any suitable construction such as known in the rope art where continuous lengths of filaments are twisted together. During the twisting process, there is a degree of compression between the strands  102 ,  104  which, due to their heated temperature, results in the strands bonding together to generally form a single integral strand having a twisted configuration as shown in FIG.  1 . It is to be understood that it is not a requirement that the strands  102 ,  104  be integral over their entire length, but rather, have contiguous intermittent portions over their length which are joined together whereby the twisted yarn  100  is prevented from unraveling during the subsequent weaving process. 
     The twisted yarn  100  is subject to air cooling, or optionally, passed through a cooling device  114 . The cooling device  114  may include a source of blowing ambient air, or air chilled to aid in bringing the twisted yarn  100  to room or ambient temperature. The resulting twisted yarn  100  is subsequently wound upon a spool  116 . It is also contemplated that the twisting apparatus  112  may be positioned before the oven  110 , as well as providing separate ovens  110  for each strand  102 ,  104  operating at the same or different temperature. Different process conditions are contemplated where the strands  102 ,  104  are of a different construction, composition or size. 
     The individual strands  102 ,  104  may be formed by hot extrusion of polymer material through a die. It is therefore contemplated that the strands  102 ,  104 , while in a heated state after extrusion, may be twisted in the twisting apparatus  112 , thereby eliminating the need for a separate oven  110 . Depending upon the exit temperature of the strands  102 ,  104  from the extruder, the strands may be allowed to air cool or provided with a separate cooling device  114  for either or both of the strands prior to twisting. 
     There will now be described one method of using the heat set twisted yarn  100  in constructing an article of furniture such as a chair, by way of one example. It is to be understood that other furniture items such as couches, tables, benches, stools, trunks and the like can also be produced in accordance with the teachings of the present invention. As shown in FIGS. 3 and 5, a chair  120  can be produced from a rigid skeletal frame  118  which will be covered with a weave of woven material produced from the heat set twisted yarn  100 . 
     The frame  118  provides an arm chair with a seat, a back rest, a pair of front legs, a pair of back legs and a pair of side arms. The seat  124  (see FIG. 5) is delineated by a connecting front member  126 , a parallel spaced apart back member  128  and a pair of parallel spaced apart side members  130 ,  132 . The front legs  134 ,  136  are constructed as parallel spaced apart vertical members joined to the free ends of the front member  126  and have outwardly turned extensions  137  providing the front legs with an L-shape. The front legs  134 ,  136  are arranged generally vertical to the floor as viewed from the front and side of the chair  120 . 
     The back legs  138 ,  140  are constructed from an angular member attached to the free ends of the back member  128 . The back legs  138 ,  140  have generally parallel spaced apart upper members  142  extending vertically from the back member  128  as viewed from the front and side and generally parallel spaced apart lower members  144 . The lower members  144  are arranged at a rearwardly extending angle as viewed from the side and extend generally vertical from the back member  128  as viewed from the rear of the chair  120 . 
     A generally U-shaped member  146  includes a center section  148  connected across the free ends of the upper members  142  of the back legs  138 ,  140  and a pair of curved spaced apart side arm members  150 ,  152  forming the side arms  154 ,  156  of the arm chair. The free ends of the side arm members  150 ,  152  are attached to the free ends of the extensions  137  of the respective front legs  134 ,  136 . The side arm members  150 ,  152  are spaced apart wider at their mouth where they connect to the extensions  137  then where they form the center section  148 . This arranges the side arms  154 ,  156  outwardly of the side members  130 ,  132 . The upper members  142  of the back legs  138 ,  140 , the back member  128  and center section  148  delineate the back  178  of the chair  120 . 
     A secondary frame can be used to provide attachment support for the woven material utilized in covering the frame  118 . Specifically, a generally U-shaped elongated rod  158  having a shape conforming substantially to the shape of the U-shaped member  146  is connected thereto in underlying relationship by means of a plurality of spaced apart ribs  160 . Another secondary support frame is positioned between the front and back legs  134 ,  136 ,  138 ,  140  underlying the seat  124 . This secondary frame is constructed from a front rod  162  connected between the front legs  134 ,  136 , a back rod  164  connected between the back legs  138 , 140  and a pair of side rods  166 ,  168  arranged in parallel spaced apart relationship connected between the front rod  162  and back rod  164  inwardly of their terminal ends. An additional front rod  170  may be positioned between the front legs  134 ,  136  underlying front rod  162 . 
     Referring now to FIGS. 4 and 5, the frame  118  is covered by weaving the heat set twisted yarn  100  into a woven material to form panels of woven material directly on the frame. A plurality of individual strands of the twisted yarn  100  are attached to various portions of the frame  118 , for example, to the secondary frame as previously described. The individual strands of the twisted yarn  100 ,as they are attached to the frame  118 , are directly woven into a predetermined weave pattern, for example, see FIG.  4 . As shown in FIG. 4, the weave pattern is a 4×4 pattern of weft and warp strands. However, the pattern may include any number of weft and warp strands of twisted yarn  100 , for example, a 2×2, 5×5, 6×6, 10×10, etc. In addition, it is not required that the woven material be symmetrical. In this regard, it is contemplated that the weave may comprise a 2×3, 3×5, 4×7, 2×5, 2×6, etc. weft and warp woven pattern. In addition, the twisted yarn  100  may be woven into integral designs. As such, the resulting panels of woven material, as shown in FIG. 4, are woven in situ directly on the frame  118 . 
     Referring to FIG. 5, there is illustrated a chair  120  which has been fabricated by the in situ weaving of the twisted yarn  100  into woven material which is attached to the frame  118 . As shown, the chair  120  includes a seat portion  124 , a front skirt portion  176 , a back rest portion  178  and side portions  180 . The front and back legs  134 ,  136 ,  138 ,  140  are wrapped with a continuous length of heat set twisted yarn  100 . In this regard, the twisted yarn  100  is wrapped in a compact spiral around the length of each leg without weaving. 
     Although the individual strands of twisted yarn  100  have been heat set, the woven material itself, as well as the twisted yarn  100  wrapped about the front and back legs  134 ,  136 ,  138 ,  140  are not heat set. As a result, the individual strands of twisted yarn  100  can shift within the weave or about the legs during use of the chair  120 . Over time, this can detract from the aesthetics of the chair. 
     In accordance with the present invention, the entire chair  120  is placed into an oven similar to oven  110  in order to heat set the attached woven material and wrapped twisted yarn  100  similar to that used in the production of the heat set twisted yarn. In the case of the chair  120 , it is contemplated that the oven will be a batch oven, as opposed to a continuous oven  110  as described with respect to the manufacture of the twisted yarn  100 . In this regard, the oven will typically be of sufficient size to hold a plurality of chairs  120 . The chairs will remain in the oven at a predetermined temperature for a predetermined residence time to cause the twisted yarn to reach about its softening temperature or above, whereby contiguous portions of the twisted yarn  100  will bond or fuse together within the weave and wrapped portions when the chair is removed from the oven and allowed to cool. The cooling process may take place either within the oven or outside the oven by being subjected to ambient air. In addition, it is also contemplated that a source of chilled air may be blown over the heated chairs  120  either in a confined housing or in an open area. 
     The temperature and residence time for the oven for heat setting the woven polymer material are similar to those as thus far described with respect to the twisted yarn. In addition, it is contemplated that the woven material can be formed from other than twisted yarn  100 . For example, individual filaments, as well as plural filaments which are untwisted can also be used in forming the woven material for adhering to the frame of the article of furniture which is to be ultimately heat set. It is further contemplated that strands of the twisted yarn  100  can also be woven with non-twisted strands to form woven material for forming portions of the article. Thus, it is to be understood, that various constructions of polymer filaments may be woven to form the woven material having various aesthetic appearances. 
     Although in accordance with the preferred embodiment, the woven material is formed in situ on the frame, it is contemplated that panels of pre-woven material may be adhered to the frame and subsequently heat set by placing the article of furniture in an oven as thus far described. It is therefore contemplated that portions of the article of furniture may be formed with woven material in situ, other portions by attaching panels of pre-woven material thereto, as well as variations thereof. In any event, the article of furniture will be placed in an oven to heat set the woven material and any wrapped portions of the article with the polymer strands of twisted or non-twisted strands. 
     The present invention has thus far been described by heating at least one of the elongated strands  102 ,  104  of polymer material to about its softening temperature whereby the strands upon twisting adhere to one another to prevent their unraveling. The twisting process may occur either before or after the heating process. The heating may take place either in an oven  110  or as a result of the strands  102 ,  104  being formed by hot extrusion of the polymer material through a die. In either case, at least one of the strands  102 ,  104  has been heated to approximately its softening temperature for adhering to the other strand upon cooling. 
     It is generally known that polymer materials can possess shape memory characteristics. This shape retention characteristic is dependent upon the nature and temperature of the polymer material. It is contemplated that this property can be utilized to form a twisted polymer yarn without the need of heating at least one strand to about its softening temperature whereby the strands will adhere to each other. By way of example, by heating at least one, and preferably both of the strands  102 ,  104 , to a temperature of between 100°-200° F. prior to twisting, the heated strands upon cooling will essentially maintain their twisted configuration. 
     It is contemplated that the slight heating of at least one strand will allow the strand to relax so as to twist with an additional strand, and retain its twisted shape upon cooling. The heating will provide the strand with a sufficient heat set to retain its shape. In accordance with this embodiment, it is not a requirement of the present invention that the strands  102 ,  104  be adhered to each other along a portion of their length such as by heating at least one of the strands to its softening temperature or above where the two strands are integrally bonded or joined together. The heat setting of the twisted yarn in accordance with this embodiment will be sufficient to prevent the strands  102 ,  104  from unraveling during the weaving process. However, the two strands  102 ,  104  can be stripped from each other by opening the twist and separating the two strands if desired. This is generally considered not possible when the strands are adhered to each other in accordance with the prior embodiment. 
     The strands  102 ,  104  may be heated prior to or after the twisting operation. In addition, the strands  102 ,  104  may be heated in one or more ovens to the same or different temperatures. In addition, the strands  102 ,  104  may be heated as a result of their hot extrusion from an extrusion die during their formation thereby eliminating the need for an oven. 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and application of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.