Patent Publication Number: US-2023146323-A1

Title: Nipper unit for a combing machine

Description:
FIELD OF THE INVENTION 
     The invention relates to a lower nipper for a combing machine having a nipper frame and a lower nipper plate. 
     BACKGROUND 
     Combing machines have a reciprocating nipper unit. The nipper unit consists of a lower nipper and an upper nipper. The upper nipper in turn has an upper nipper plate and the lower nipper has a lower nipper plate, wherein the upper nipper plate together with the lower nipper plate forms a clamping line, in the closed state of the nipper unit, in which line a fiber tuft is held for combing. The two ends of the nipper plates which encounter one another are referred to as nipper lips. The combing is carried out by a rotating circular comb. The circular comb is equipped with nippers, by means of which the fiber tuft is combed out. In today&#39;s construction of combing machines, the tooth tips of the circular comb move at a small distance from the nipper plates, wherein a distance of 0.3 mm is not unusual. 
     The lower nipper plate is held free of play in a nipper frame. The nipper frame is connected to a drive via pivot arms. During operation, the upper nipper plate is abruptly lowered onto the lower nipper plate during a closing process, by spring force. This process of closing the nipper unit is repeated over 600 times per minute in today&#39;s high-performance machines. The nipper lips of the nippers encounter one another. This rapid impact of the upper and lower nipper plates results in a mechanical bending load on the lower nipper plate, which leads to a slight bending of the lower nipper plate during each closing process. Due to the elasticity of the lower nipper plate, this brief bending of the lower nipper plate is already canceled out again after the closing process, and the lower nipper plate again rests on the nipper frame in a gap-free manner, at the point of attachment. This bending opens up a gap between the lower nipper plate and the nipper frame at the fastening point of the lower nipper plate on the nipper frame. As a result, dirt or fiber material penetrates into this gap, which causes the gap to no longer be completely closed after a longer period of operation, and, when fastened, the lower nipper plate no longer rests in a gap-free manner on the nipper frame. Due to the fact that there is a greater distance between the fastening point of the lower nipper plate and the clamping line of the nipper unit, even very small amounts of dirt can lead to a greater change in the distance between the circular comb and the nipper plates, due to the lever effect. In this case, the change due to the construction is always a reduction in the distance. The result is a collision between the circular comb and the nipper plates, which can cause significant damage to the comb machine. 
     SUMMARY OF THE INVENTION 
     An object of the invention is therefore that of proposing a lower nipper which eliminates the known disadvantages and enables dimensional accuracy of the distance between the circular comb and the nipper plates during longer operation. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In order to achieve the objects, a lower nipper is proposed for a combing machine having a nipper frame and a lower nipper plate, wherein the nipper frame has a support surface for contact with the lower nipper plate, and a first portion of the lower nipper plate rests against the support surface and said lower nipper plate is fastened to the nipper frame by means of at least one fastening screw, and a second portion of the lower nipper plate projects beyond the support surface. For sealing the support surface, a transition from the first portion to the second portion of the lower nipper plate is connected to the nipper frame by a resilient seal. The second portion comprises the lower nipper lip, which strikes the upper nipper lip of the upper nipper plate when the nipper unit is closed. In this case, the upper nipper lip presses the lower nipper lip downwards, which corresponds to a direction away from the support surface of the nipper frame. Due to the distance between the lower nipper lip and the fastening screw, a bending force results which acts on the lower nipper plate. In this case, the lower nipper plate briefly yields and is bent in its resilient region. As a result of the bending of the lower nipper plate, a gap opens between the support surface and the lower nipper plate, in the transition from the first to the second portion of the lower nipper plate. This gap is opened only briefly and is also small in width, although dirt can diffuse into the gap over a longer operating time. This gap is closed by the resilient seal now attached. In this case, the elasticity of the seal is selected in such a way that a tearing of the seal by the movements of the lower nipper plate is prevented. Preferably, a resilient adhesive is provided as the resilient seal, for example a sealing compound made of MS polymer. MS is modified silanes. The use of silicone or other resilient adhesives would also be conceivable. 
     Advantageously, the resilient adhesive is applied at a thickness of at least 1 mm. In order to overcome the high number of movements of the lower nipper plate due to the comb cycles, without impairing the sealing compound, a correspondingly large thickness of the seal must be selected; in this case 1 or more millimeters have proven to be successful. 
     In an alternative embodiment, the resilient seal is designed as a rubber profile. Advantageously, the rubber profile is glued to the lower nipper plate and the nipper frame. Further alternative embodiments can be seen in the use of adhesive tapes, a liquid rubber or a flexible lacquer. The materials used as a seal must satisfy the requirements of continuous operation and functioning; in this case it must be ensured that no dirt can penetrate between the support surface of the nipper frame and the lower nipper plate. 
     A combing machine comprising a lower nipper as described above is also proposed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is shown and explained in more detail with reference to an embodiment shown below. In the drawings: 
         FIG.  1    is a schematic view of a nipper unit of a combing machine according to the prior art, in the open position; 
         FIG.  2    is a schematic view of a nipper unit of a combing machine according to the prior art, in the closed position; 
         FIG.  3    is a schematic view of a cross section of a first embodiment of a fastening of a lower nipper plate to a nipper frame, and 
         FIG.  4    is a schematic view of a cross section of a second embodiment of a fastening of a lower nipper plate to a nipper frame. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein. 
       FIG.  1    is a schematic view of a nipper unit of a combing machine according to the prior art, in the open position, and  FIG.  2    shows the same nipper unit in the closed position. The nipper unit shown comprises a nipper frame  1 , a lower nipper plate  3  which rests on a support surface  2  of the nipper frame  1  and is fastened by fastening screws  6 , and an upper nipper plate  21  which is mounted pivotably on the nipper frame  1 . The lower nipper plate  3  comprises a lower nipper lip  11 , and the upper nipper plate  21  comprises an upper nipper lip  12 . 
     A feed cylinder  13  is rotatably mounted in the nipper unit, which feed cylinder performs a discontinuous movement during a comb clearance, in order to introduce the padding  18 , unrolled from a reel (not shown), to a circular comb  14 , which is intended for combing and is rotatably arranged below the nipper unit. The circular comb  14  has a circular comb segment  15  equipped with teeth for combing a fiber tuft  19 . During this combing process, the nipper unit is in a rear position shown in  FIG.  2   , wherein the nipper unit is closed. 
     Closing of the nipper unit takes place by way of the upper nipper lip  12  encountering the lower nipper lip  11 . In this case, the upper nipper plate  21  is pressed by means of a compression spring  22  against the lower nipper plate  3 . As a result of the impact of the upper nipper lip  12  on the lower nipper lip  11 , a pressure is briefly exerted on the lower nipper plate  3  which is so high that the lower nipper plate bends downwards, as a result of which the lower nipper plate  3  is briefly released from the support surface  2  between the fastening screw  6  and the end of the support surface  2 . In this closed position of the nipper unit, a fiber tuft  19  is held by the nipper lips  11  and  12  of the nipper plates  5  and  21  resting against each other. The fiber tuft  19 , which protrudes from the nipper unit in this way is combed by the circular comb segment  15  by a rotation of the circular comb  14 . Subsequently, the nipper unit is transferred into the open position shown in  FIG.  1   , in which it is open. In this position, a fixed comb  17  points into the padding end protruding beyond the nipper unit. By way of a forward movement of the nipper unit, the padding end now enters a clamping line of an upstream tear-off roller pair  16  and is soldered there to a non-woven fabric  20 . 
     In order to achieve a qualitatively good combing of the fiber tuft  19 , a distance  23  is provided between the nipper unit and the circular comb segment  15  and is kept as low as possible and is generally 0.3 mm or less. Due to a structural length of the lower nipper plate  3  from the fastening screw  6  to a contact point with the upper nipper lip  12 , the smallest bending of the lower nipper plate  3  also leads to the formation of a gap between the lower nipper plate  3  and the support surface  2 . 
       FIG.  3    is a schematic view of a cross section of a first embodiment of a fastening of the lower nipper plate  3  to the nipper frame  1 . The nipper frame  1  comprises a support surface  2  for the gap-free contact of the lower nipper plate  3 . The lower nipper plate  3  comprises a first portion  4  for contact with the support surface  2  and a second portion  5  protruding beyond the support surface and comprising the lower nipper lip  11 . The lower nipper plate  3  is firmly screwed to the nipper frame  1  by means of the first portion  4  resting against the support surface  2 , using fastening screws  6 . The upper nipper plate (not shown) striking the lower nipper lip  11  of the lower nipper plate  3  with a closing force  9  causes a brief bending of the lower nipper plate  3 . Due to the resilience of the lower nipper plate  3 , the bending triggered by the abruptly striking closing force  9  is restored. The movement  10  of the lower nipper plate  3  results. In order to prevent dirt from entering the briefly opening gap between the nipper frame  1  and the lower nipper plate  3 , a seal  7  is provided. In the embodiment shown, the seal  7  is provided as a resilient adhesive of a thickness  8 . In this case, the thickness  8  is dependent on a choice of material for the seal  7 . The edge of the support surface  2  may delimit a transition between the first portion  4  and the second portion  5 , and the seal  7  may be provided on the transition such as to connect the lower nipper plate  3  to the nipper frame  1 . 
       FIG.  4    is a schematic view of a cross section of a second embodiment of a fastening of the lower nipper plate  3  to the nipper frame  1 . The lower nipper plate  3  is placed, by a first portion  4 , on a support surface  2  of the nipper frame  1 , and is connected to it by fastening screws  6 . A second portion  5  of the lower nipper plate  3  that comprises the lower nipper lip  11  projects beyond the support surface  2  of the nipper frame  1 . In the embodiment shown, the seal  7  is provided as a rubber profile. The rubber profile is connected in a dust-tight manner to the nipper frame  1  and the lower nipper plate  3 , for example by means of an adhesive. 
     The present invention is not limited to the embodiments shown and described. Modifications and a combination of the features within the scope of the claims are also possible, even if they are shown and described in different embodiments. 
     LEGEND 
     
         
           1  nipper frame 
           2  support surface 
           3  lower nipper plate 
           4  first portion of the lower nipper plate 
           5  second portion of the lower nipper plate 
           6  fastening screw 
           7  seal 
           8  thickness of the seal 
           9  closing force 
           10  movement lower nipper plate 
           11  lower nipper lip 
           12  upper nipper lip 
           13  feed cylinder 
           14  circular comb 
           15  circular comb segment 
           16  pair of tear-off rollers 
           17  fixed comb 
           18  padding 
           19  fiber tuft 
           20  non-woven fabric 
           21  upper nipper plate 
           22  compression spring 
           23  circular comb distance