Patent Publication Number: US-2020281294-A1

Title: Apparatus for compressing and heating a shrink sleeve

Description:
The invention relates to an apparatus for compressing and heating a shrink sleeve into one of whose ends an end of a strand of a person&#39;s own hair is inserted and into whose opposite end is inserted a foreign hair strand in order to extend the hair, a hot-melt adhesive being provided inside the sleeve. 
     It is known to extend hair on the head using a sleeve made of shrinkable plastics into whose one end is inserted a strand of a person&#39;s own hair and into whose opposite end is inserted a foreign hair strand in order to be bonded to each other inside the sleeve by an adhesive. In this case, the sleeve is pressed together in the region of the adhesive by hand by rolling the sleeve between two fingers. Such a method of working is time-consuming and labor-intensive and leads to results having different degrees of accuracy. 
     The object of the invention is to provide an apparatus that considerably reduces the workload when extending head hair. 
     According to the invention, this object is attained in that the apparatus comprises two clamping jaws between which the shrink sleeve is received and is deformed by pressure and heat, and at least one of which clamping jaws has a heating element. 
     With such an apparatus, it is possible to extend hair with a small amount of effort and in the shortest amount of time possible, with consistent precision. 
     In this case, it is preferably proposed that the clamping surface of at least one clamping jaw has at least one recess and/or at least one projection that deforms the shrink sleeve and the hot-melt adhesive. As a result, after the hot adhesive and the sleeve have cooled down, an optimum sleeve shape is reached that has a diameter that decreases at the two ends. As a result, the hot-melt adhesive is optimally distributed inside the shrink sleeve. The shrink sleeve is also optimally deformed into a shape having tapering ends and a slightly thicker portion in the central region. 
     In this case, it is particularly advantageous for the recess(es) and/or the projection(s) to be deformed and/or constructed such that a smaller amount of pressure is exerted on the outside of the shrink sleeve in the central region thereof than in the regions that are closer to the two shrink sleeve ends. 
     It is preferably proposed that each clamping jaw is at the end of a two-lever assembly and the two levers are fastened to each other by a pivot. In this case, the two levers can be articulated to each other such that, when the lever ends remote from the clamping jaws are pressed toward each other, the clamping jaws move away from each other. 
     It is also advantageous here for a spring element to be mounted on the levers and press the clamping jaws against each other. In this case, the spring force is preferably adjustable. 
     An effective method of working is achieved when the clamping jaws have two or more seats for shrink sleeves that are parallel to one another. 
     Fast and safe heating is achieved when the heating element generates the heat by ultrasound. It is preferably proposed that at least one of the clamping jaws has at least one opening or hole that ends on the shrink sleeve and via which the hot-melt adhesive can be influenced. As a result, the flow of the hot-melt adhesive can be controlled by inserting a pin or wire such that the hairs can be securely stuck together in a smaller space. 
     The shrink sleeves are particularly easy to work with and insert into the clamping apparatus when the shrink sleeve has at least one recess, in particular a groove or annular groove, and/or at least one projection, in particular an annular bulge, in its outer surface in order to fix the shrink sleeve to the jaws of the clamping apparatus. 
    
    
     
       One embodiment of the invention is shown schematically in the drawings and will be described in more detail in the following, in which: 
         FIG. 1  is a section through two clamping jaws of a compressing apparatus along the axis of the shrink sleeve, 
         FIG. 2  is a cross section through the clamping or compressing apparatus, 
         FIG. 3  is a perspective view of the profile-shaped clamping jaws fastened to the levers, and 
         FIG. 4  shows a cross section through the clamping jaws comprising an additional clamp. 
     
    
    
     The clamping or compressing apparatus according to the invention comprises two levers  11 ,  12  that can cross and can be articulated to each other. However, here the two levers  11 ,  12  are connected to each other by a pivot  13  and do not cross each other so that, when the two outer lever ends are pushed away from each other, the two inner lever ends move toward each other. A compression spring  14  is between the outer lever ends to urge the outer lever ends away from each other so that the two inner lever ends are pressed together against this pressure. Clamping jaws  5 ,  6  are fastened on the inside between the inner lever ends between which a shrink sleeve  1  is placed. 
     The end of a strand of a person&#39;s own hair  2  is inserted into one end of the sleeve and the end of a foreign hair strand  3  is inserted into the opposite end. The two strands of hair overlap in the center of the shrink sleeve  1 , at least in part, and a hot-melt adhesive (hot melt)  4  is provided on the internal wall of the shrink sleeve  1  in this central region so that this adhesive melts in the shrink sleeve when pressure and heat are applied from the outside and penetrates between the hairs of the two strands in order to attach them to each other after the adhesive has cooled. 
     In order to apply the necessary pressure and the necessary heat to the shrink sleeve from the outside, the shrink sleeve  1  is placed between the two clamping jaws  5 ,  6 , and here the two clamping jaws  5 ,  6  have recesses  8  on their confronting faces in the central region of the shrink sleeve, and therefore, when the two clamping jaws  5 ,  6  are pressed together in the central region of the shrink sleeve, a smaller amount of pressure is exerted in this central region than at the two ends of the shrink sleeve. In this case, the heat required for the hot-melt adhesive is generated by heating elements, in particular by sources of ultrasound, that are mounted in one or in both clamping jaws  5 ,  6 . 
     Due to the recesses  8 , a smaller amount of pressure is exerted in the central region of the shrink sleeve than at the ends, and therefore the hot-melt adhesive becomes thinner toward the two ends and has a larger diameter in the central region and the shrink sleeve is accordingly also deformed such that it has a greater diameter in the central region and tapers so as to be narrower at both ends. As a result, the shrink sleeve conforms to the hair strands. However, after the hot-melt adhesive  4  has solidified, the shrink sleeve is preferably removed such that only the hot-melt adhesive then remains on the two hair strands  2 ,  3 , and in this case has a lens-shaped longitudinal section. 
     The clamping jaws  5 ,  6  preferably have two or more seats for shrink sleeves  1  that are parallel to each other such that a plurality of shrink sleeves can be worked on at the same time. 
     So that the shrink sleeve or shrink sleeves  1  can be inserted into the seat(s) particularly easily and held in position there, it is proposed that at least one projection or in particular an annular bulge be provided on the outside of the shrink sleeve that fits into a corresponding recess in the clamping jaws. The shrink sleeves are therefore then also still held securely in the clamping jaws before the clamping jaws are pressed together. 
     In the embodiment of  FIG. 3 , the clamping jaws  5 ,  6  are formed by profiles extending parallel to each other and are each fastened to one of the two levers  11 ,  12 , in particular integrally formed therewith, by one end thereof. In this case, the clamping jaw profiles form an angle α of from 40 to 60°, preferably 45°, together with the levers  11 ,  12  in order to be able to comfortably move the clamping jaws  5 ,  6  closer to the scalp so that the clamping jaws lie approximately parallel to scalp. In this position, a plurality of shrink sleeves  1  can be simultaneously contacted and deformed by pressure and heat between the clamping jaws in order to bond the foreign hair strands to the strands of a person&#39;s own hair. 
     The confronting faces of the two clamping jaws  5 ,  6  between which the shrink sleeves are provided have projecting ridges  15  to  18  that extend parallel to the clamping jaw axes or extensions, and can also be characterized as projecting ridges having a spacing A from one another such that a recess  8  is formed in the particular clamping jaw between the ridges, and therefore the two recesses  8  form a space when the clamping jaws are pressed together, in which space lies the central region of the shrink sleeve in which the hot-melt adhesive and the two ends of the strands are located. 
     If the two clamping jaws  5 ,  6  are pressed together by the levers  11 ,  12  together, the ridges  15  to  18  on either side of the central region of the shrink sleeve constrict and at the same time heat this sleeve. It is advantageous here for the two clamping jaws to be released from each other shortly after the initial compressing and heating in order to give the adhesive the opportunity to distribute itself better. In this position, the shrink sleeve  1  is also held by an additional clamp  19  that acts on the clamping points of the shrink sleeve and therefore also holds the shrink sleeve in place. In this case, the clamp  19  has a profile  20  that has a U-section, and free ends  21 ,  22  of the profile legs that face the clamping points engage over the outside of one of the clamping jaws  5 ,  6 . 
     The profile-shaped clamping jaws  5 ,  6  and in particular the additional clamp  19  make it possible for a plurality of shrink sleeves of the head to be deformed simultaneously and for the ends of the two hair strands  2 ,  3  to be securely bonded to each other. The sleeve is then removed from the hair-strand bonding point. For this purpose, the shrink sleeve  1  has at least one tear-open seam. The exact design and handling of the shrink sleeve is described in WO 2014/086483. 
     One to three transverse holes  23  are made in at least one of the two clamping jaws  5 ,  6 , which end at the shrink sleeve  1 . A rod or pin can be inserted into one of these holes to press the outside of the sleeve  1  by its inserted end in order to influence the flow of the hot-melt adhesive. Therefore, this flow can accumulate in the central region, for example.