Patent Publication Number: US-6910249-B2

Title: Apparatus on a draw frame for textile fibre material

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims the priority of Germany Application No. 102 34 414.0, filed Jul. 29, 2002, and German Application No. 103 31 468.7, filed Jul. 11, 2003, which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The invention relates to an apparatus on a draw frame for textile fibre slivers. 
   It is known to weight the top rollers of a drawing system of successively arranged pairs of rollers comprising a bottom and a top roller, in which, during operation, the top rollers are pressed against the bottom rollers by weighted pressure elements in pressure arms, wherein two pressure elements with a common holding element are associated with each top roller and the weighting device is removable. 
   In a known apparatus, a pressure arm comprising two lateral supports with a common crosshead is associated with each top roller. A pneumatic pressure-applying element is mounted on each lateral support. The pressure arm is rotatable about a pivot bearing, which is provided at the lower end of one lateral support and is secured to the machine frame by way of a press member. A pneumatic compressed air line is located inside the crosshead and the lateral supports. 
   It is an aim of the invention to further improve the known apparatus. 
   SUMMARY OF THE INVENTION 
   The invention provides an apparatus on a draw frame for textile fibre slivers, having a drawing system having successively arranged pairs of rollers comprising a bottom and a top roller, in which, during operation, the top rollers are pressed against the bottom rollers by one or more removable weighted pressure devices, wherein at least one said pressure device for weighting a said top roller has two or more pressure elements, a said pressure element being rotatably or pivotally mounted at a centre of rotation or a pivot bearing and the pressure elements being connected with one another by a supporting element. 
   The invention also provides a drawing system for a draw frame, comprising successively arranged pairs of rollers comprising a bottom roller and a top roller and a weighting device for applying pressure to a top roller of a said pair of rollers, the weighting device comprising a pair of spaced pressure elements and a support element extending between said pressure elements, said pressure elements comprising structural members of said weighting device. 
   The fact that the pressure elements and the pressure channel are able to be used as supporting structural elements enables the apparatus according to the invention to be of compact construction. In particular, savings in space can be made both in the direction of the flow of the fibre material and in headroom. 
   The pressure element advantageously comprises a reciprocating part, for example, a ram. The ram preferably has a circular cross-section. The pressure elements are advantageously pneumatic cylinders. The pneumatic cylinder preferably has a rectangular cross-section. The width of the pneumatic cylinder is advantageously the same as or smaller than the width or the diameter of the top roller. The pneumatic cylinder is preferably a supporting element of the pressure arm. The pneumatic cylinder is advantageously mounted at the centre of rotation or pivot bearing. The centre of rotation or pivot bearing is advantageously mounted in the region of the lower end of the pneumatic cylinder facing the top rollers. The pneumatic cylinder preferably has a covering. The centre of rotation and pivot bearing is advantageously arranged on the lower covering of a pneumatic cylinder. The supporting element is preferably mounted in the region of the upper end of the pneumatic cylinders remote from the top rollers. The supporting element preferably forms the upper covering of the pneumatic cylinders of a pressure arm. The supporting element advantageously forms a bridge between the pneumatic cylinders of a pressure arm. The supporting element advantageously forms a crosshead for the two pneumatic cylinders. The supporting element is advantageously hollow inside. The supporting element preferably forms a compressed air channel. The pneumatic cylinders are advantageously connected to the compressed air channel. The pneumatic cylinders and the supporting element preferably form a portal-form pressure arm. The supporting element advantageously accommodates electrical leads. The pressure arm is preferably arranged in the same plane as the top roller. The longitudinal axis of the supporting element is preferably arranged parallel to the longitudinal axes of the respective top roller. The pneumatic cylinders are advantageously arranged perpendicular to the top roller. The pneumatic cylinders are preferably arranged perpendicular to the supporting element. The supporting element is advantageously an extruded section, for example, of aluminium. The lower covering of a pneumatic cylinder is preferably rotatably mounted at a pivot bearing. A locking device is advantageously associated with the respective other pneumatic cylinder. A locking device is preferably associated with the lower covering of the respective other pneumatic cylinder. At each pressure arm advantageously a pneumatic cylinder or its lower covering is articulated at a pivot bearing. At each pressure arm a locking device is preferably associated with a pneumatic cylinder or its lower covering. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  a schematic side view of the drawing system of a draw frame with the apparatus according to the invention; 
       FIG. 2  a section through a portion of  FIG. 1  corresponding to I—I ( FIG. 1 ) with a pneumatic top roller weighting device; 
       FIG. 3  a perspective view of the drawing system with four portal-form pressure arms, which are associated with the top rollers of the drawing system; 
       FIG. 4  a front view of the apparatus according to the invention, in which the portal-form pressure arm with top roller swung out; 
       FIG. 5  a pneumatic cylinder, for which the lower covering is articulated at a pivot bearing; 
       FIG. 5   a  a cross section through a pneumatic cylinder according to  FIG. 5 ; 
       FIG. 6  a schematic longitudinal section through two pneumatic cylinders with supporting element, which takes the form of a compressed air channel; 
       FIG. 7  a front view of a pressure arm with integral housing; 
       FIG. 7   a  a perspective view of the partially opened housing according to  FIG. 7  with lid; 
       FIGS. 8   a,   8   b  a spring-weighted pressure tracer with rotating double-angle lever and 
       FIGS. 9   a,   9   b  the pressure arm with ( FIG. 9   a ) and without top roller ( FIG. 9   b ). 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIG. 1 , a drawing system S of a draw frame, for example, a HSR draw frame made by Trützschler GmbH &amp; Co KG of Mönchengladbach, Germany, is provided. The drawing system S is designed as a 4-over-3 drawing system, that is, it comprises three bottom rollers I, II, III (I being the bottom output roller, II the middle bottom roller, III the bottom intake roller) and four top rollers  1 ,  2 ,  3 ,  4 . Drafting of the composite sliver  5  from a plurality of fibre slivers takes place in the drawing system S. The draft is made up from the preliminary draft and the main draft, and the roller pairs 4/III and 3/II form the preliminary drafting zone and the roller pairs 3/II and 1, 2/I form the main drafting zone. The bottom output roller I is driven by the main motor (not shown) and hence determines the rate of delivery. The bottom intake and middle bottom rollers III and II respectively are driven by a variable speed motor (not shown). The top rollers  1  to  4  are pressed against the bottom rollers I, II, III by pressure devices  9   1  to  9   4  (weighting devices) in pressure arms  11   a  to  11   d  pivotable about pivot bearings (see FIGS.  3  and  4 ), and are hence driven by way of frictional engagement. The direction of rotation of the rollers I, II, II;  1 ,  2 ,  3 ,  4  is indicated by curved arrows. The composite fibre sliver  5 , which consists of a plurality of fibre slivers, runs in direction A. The bottom rollers I, II, III are mounted in press member  14  (see  FIG. 3 ) which are arranged on the machine frame  15 . 
   Referring to  FIG. 2 , the pressure device  9   4  has a pneumatic cylinder  9  comprising an upper cover (supporting element  12 ) and a lower cover  13   a.  The pneumatic cylinder  9  forms a cylinder unit having a cylinder cavity  17  comprising two parts  17   a  and  17   b,  in which a piston  18  is guided by means of a ram  19  in a sliding bushing  20 . The roller journal  4   a  of the pressure roller  4  passes right through an opening in a holding plate  27  and engages in a bearing  22   a.  The bearing  22   a  receiving the pressure roller  4  extends in a space between the ram  19  and the roller journal III a  of the bottom roller III. The bearing  22   a  is mounted on the cover  13 . A diaphragm  16  divides the cylinder cavity  17  into pressure regions. In order to generate pressure in the upper part  17   a  of the cylinder cavity  17 , compressed air p 1  can be admitted to this space by means of a compressed air connection  23 . Air is evacuated from the lower part  17   b  of the cylinder cavity  17  through a vent bore  24 . Analogously, air can be evacuated from the upper part of the cylinder cavity  17  and compressed air can be admitted to the lower part of the cylinder cavity  17 . In operation, after a fibre sliver  5  has been guided over the bottom rollers I, II, III, the pressure arms  11  are pivoted into the working position shown in FIG.  1  and fixed in this position by a fixing device (not shown), so that the pressure rollers I, II, III are able to exert pressure. Application of pressure occurs on the one hand as a consequence of each of the rams  19  being located on the corresponding bearing  22 , and on the other hand in that an overpressure is generated in the void above the diaphragm  16 . The ram  19  therefore presses with its other end on the bearing  22 , in order to generate the said clamping between the top roller  4  and the bottom roller (drive roller III). The ram  19  is displaceable in the direction of the arrows D, E. 
   In the embodiment of  FIG. 3 , each top roller  1  to  4  has associated with it a respective portal-form pressure arm  11   a,    11   b,    11   c,    11   d,  which, seen in plan view, is oriented parallel to the longitudinal axis of the respective top roller  1  to  4 . The pressure arms  11   a  to  11   d  are shown in the closed position. The bottom rollers I to III are mounted in press members  14   a,    14   b  and  14   c  respectively, which are displaceably mounted on the machine frame  15 . At the same time, two pressure elements  9  ( 9   a   1  and  9   a   2 ; to  9   d   1  and  9   d   2 ), are associated with each top roller  1  to  4  and are connected with one another by a common supporting element  12 . 
   According to  FIG. 4 , the portal-form pressure arm  11   a,  which consists of two lateral pneumatic cylinders  9   a   1  and  9   a   2  (pressure elements), a common supporting element  12   a  and two cover elements  13   a   1  and  13   a   2 , is associated with the top roller  4 . The cover elements  13   a   1  and  13   a   2  are mounted at the lower ends of the pneumatic cylinders  9   a   1  and  9   a   2  and form the lower cover thereof. The supporting element  12   a  is mounted at the upper ends of the pneumatic cylinders  9   a   1  and  9   a   2  and forms their upper cover. Together with the top roller  4 , the pressure arm  11   a  is upwardly pivoted about a pivot bearing  10  (see FIG.  5 ). The cover elements  13   a   1  and  13   a   2  are, seen in side view, of angular (right-angled) construction, one arm of the angle covering a respective pneumatic cylinder  9   a   1 ,  9   a   2 . The other angle arm of the cover element  13   a   1  is rotatably mounted in the region of its free end at the pivot bearing  10 . The other angle arm of the cover element  13   a   2  has a locking device in the region of its free end, the locking device comprising an aperture  26 , through which a sliding locking rod (not shown) mounted on the machine frame  15  engages. The pressure arm  11   a  is shown in the opened position. 
   The embodiment of  FIG. 5 , the lower cover element  13  of the pneumatic cylinder  9  is articulated on the bearer  14  by way of a pivot bearing  10  so as to rotate in the direction of the arrows B and C. 
   In a further embodiment shown in  FIG. 6 , the supporting element  12   a  consists of an extruded section, for example of aluminum, which is hollow inside and the end faces of which are closed. In the end face regions there are two openings  12 ′,  12 ″ in a lateral wall. This creates a channel  12 ′″, through which compressed air p is able to pass. One connection  23  for the admission of compressed air p 1  is therefore sufficient, part of the compressed air flowing into the pneumatic cylinder  9   a   1  and the remainder flowing via the channel  12 ′″ of the supporting member  12   a  into the pneumatic cylinder  9   a   2 . The pneumatic cylinders  9   a   1  and  9   a   2  have a respective connection  24  and  25  for discharge of the compressed air p 2  and p 3  respectively. 
   As shown in  FIG. 1 , a central compressed air line  28  is provided, to which four branch lines  28   a  to  28   d  leading to pneumatic cylinders of pressure devices  9   1  to  9   4  are connected. The compressed air line  28  is connected to a compressed air source  29 . 
   The invention has been explained with reference to an example in which a pivot bearing and a locking device are associated with each pressure arm. The invention also includes a construction in which two combined pivot bearings and locking devices are associated with a pressure arm. 
   The apparatus according to the invention has been illustrated by way of the example of a draw frame with pneumatic weighting of the top rollers. The invention also includes a draw frame in which the top rollers are loaded mechanically, for example, by springs. 
     
   According to  FIGS. 7 ,  7   a,  the portal-form pressure arm  11   a  is associated with the top roller  4 . (A corresponding pressure arm  11 —not shown herein—is associated with the top rollers  2  to  4 .) The pressure arm  11   a  is embodied as housing  30  which is injection-molded of glass-fiber reinforced plastic. The housing  30  is an integral component having a uniform design and comprising the supporting element  12   a,  the two bodies of the pressure elements  9   a   1  and  9   a   2  (pressure cylinders), two intermediate elements  31   a  and  31   b  and  2  holding elements  32   a  and  32   b.  The supporting element  12   a  is designed as a channel that is open on one side, has an approximately U-shaped cross section and has the pneumatic lines  34  and the electric lines  35  arranged on the inside. The open side of channel  34  can be closed off with a removable lid  36  of glass-fiber reinforced plastic having an approximately U-shaped cross section, which is elastic enough, so that it can be pressed against the channel  33  for fastening it. The housing  30  preferably has a one-piece design. The integral housing  30 , which combines all essential operational elements for holding and weighting the respective top rollers  1  to  4 , can thus be produced economically. At the same time, the complete pressure arm  11   a  to  11   d  can be rotated easily around the pivot bearing  10  and can be locked and unlocked with the locking device  26 . 
     FIGS. 8   a,    8   b  show that a pressure tracer  37  that is weighted with a compression spring  38  is arranged on the intermediate element  31   b.  The pressure tracer  37  can be displaced in the direction of arrows F, G. A double lever  39  is furthermore mounted on the intermediate element  31   b,  which can pivot around a pivot bearing  40  in the direction of arrows H, I. According to  FIG. 8   a,  the portion of angle arm  39   b  that projects at a right angle grips beneath and holds the shaft journal  41   b  of bearing  22   b  for the top roller  4 . If the pressure arm  37  according to  FIG. 8   b  is pushed in the direction F, against the angle arm  39   a  of the angle lever  39 , then the angle arm  39   a  turns in the direction of arrow H around the pivot bearing  40 , so that the angle arm  39   b  releases the shaft journal  41   b . In this way, the top roller  4  with bearings  22   a,    22   b  can be removed completely from the pressure arm  11   a,  as shown in  FIG. 9   b .  FIG. 9   a  shows the pressure arm  11   a  with top roller  4  in the upward pivoted position. Two recesses  43   a,    43   b  are provided on the double lever  39 , wherein an elastically loaded detent  42  or the like engages in these recesses. 
   The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.