Patent Publication Number: US-7594522-B2

Title: Shaft transmission for a weaving machine

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims the priority of European Patent Application No. 06 021 001.0, filed on Oct. 6, 2006, the subject matter of which, in its entirety, is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The invention relates to a shaft transmission for a weaving machine. 
   Shaft transmissions, also referred to as “eccentric machines”, are used for driving the heald shafts of weaving machines. The shaft transmission has the task of deriving several different back-and-forth movements from the uniform rotation of a shaft in order to drive the heald shafts. 
   In conjunction with this, document WO 2005/098108 A1 has disclosed a shaft transmission that comprises a transmission frame with a rotatably supported shaft that bears several cam disks. These cam disks are associated with cam disk followers that actuate rockers. Connected to the rockers is a rod assembly used for the transmission of the drive motion to the respective heald shaft. The shaft is driven, via a bevel gear transmission consisting of a crown wheel and a conical wheel, by a drive shaft that is connected to a drive motor. 
   The form of each cam disk defines the form of the rockers of the associate heald shaft. Occasionally, the issue of changing the form of motion arises. In order to resolve this, the cam disks need to be replaced. 
   Regarding this, the aforementioned document suggests to provide the shaft, on its end away from the bevel gear transmission, with a removable end-piece that is supported in a support arrangement, which, in turn is detachably held by the transmission frame. If the cam disks are to be exchanged, the support arrangement is detached from the transmission frame. In addition, the end-piece is released from the shaft. Thereafter, the unit consisting of the end-piece and the support arrangement can be removed, thus leaving a narrow gap between the free end of the shaft and the transmission frame. Through said gap, individual cam disks pulled off the shaft in axial direction can be removed from the transmission frame and, conversely, the new cam disks can be mounted on the shaft. 
   This technical solution requires the disassembly of the cam disk package held on the shaft. 
   It is the object of the invention to simplify changing of the cam disks. 
   SUMMARY OF THE INVENTION 
   The above object is generally achieved with the shaft transmission in accordance with claim  1 , the invention which comprises a transmission frame, a shaft arrangement that is rotatably supported in the transmission frame and has at least one cam support section and one drive section, whereby these sections can be separated from each other. At least one cam disk that is held on the first cam support section and a gear mechanism that comprises at least two gear wheels coming in meshing engagement with each other are provided, with one of the gear wheels being non-torsionally connected with the drive section ( 17 ) of the shaft arrangement ( 8 ), and the other gear wheel being non-torsionally connected with the drive shaft ( 6 ). 
   The shaft transmission in accordance with the invention uses as the shaft for at least one, preferably several, cam disks a shaft arrangement which can also be viewed as a divided shaft. Consequently, the shaft is divided into a cam support section and a drive section, which, when in operative state, are connected at a separating site, for example, by means of a suitable clutch arrangement, in a non-torsional manner and preferably exhibiting flexural strength. If one or more cam disks are to be replaced, the cam support section and the drive section of the shaft arrangement are separated from each other. While the cam support section and the cam disks can be removed from the transmission frame, the drive section may remain in the shaft transmission. Therefore, the gears of the gear mechanism remain meshed. Following reassembly, the existing gear play of the gears that needs to be maintained in a highly precise manner does not need to be readjusted. 
   With the removal of the cam support section from the transmission frame sufficient free space is created in order to be able to remove the package consisting of the cam disks and, optionally additional elements, and thus replace it with another package. Also, if needed, individual cam disks of this package may be replaced. 
   Referring to the present solution of the technical problem, the separation of the shaft arrangement at a point of the torque transfer path between the package consisting of the cam disks and the gear mechanism has been suggested. This provides an easily executable option for changing the cam disks, without requiring any disassembly of the gear mechanism. Cam disks need not be replaced individually, but may be replaced as a group, thus substantially reducing assembly times. 
   Preferably, several cam disks forming a package are provided, said package being detachably connected with the cam support section. For example, the cam disks may be seated on a bushing that can be shifted in axial direction with the cam support section but is non-torsionally connected thereto. During disassembly, the cam support section can be pulled in axial direction out of the cam disk package, whereupon the cam disks, or the package consisting of the cam disks, can be laterally removed from the installation space. 
   The drive section of the shaft arrangement is preferably associated with at least one bearing arrangement located between the separating site and the gearwheel. This bearing arrangement holds the drive section in the transmission frame, while the cam support section and the cam disks may have been removed from the transmission frame. Preferably, the drive section merely forms a short shaft butt-end that projects only minimally, or not at all, beyond the bearing arrangement. The separating site or clutch arrangement is preferably located directly next to the bearing arrangement which is located between the cam disk package and the gearwheel. Thus, by removing the cam disk section, the free space between the two bearing arrangements can be freed along the entire length of the cam disk package. 
   Preferably, the cam support section is held so as to be movable in axial direction in a bearing arrangement. The axial position of the shaft arrangement is preferably defined by the bearing arrangement between the cam disk and the gearwheel. Upon releasing the separating point between the cam support section and the drive section, the cam support section can be pulled out of its bearing arrangement in axial direction. Disassembly and assembly of the cam arrangement is particularly easy. 
   In order to connect the cam support section with the drive section, there is preferably provided a clutch arrangement which may be configured as a friction clutch and/or as a positive clutch. For example, the clutch arrangement may be a play-free friction clutch, e.g., configured as a cone clutch. A clamping screw or another suitable clamping means can be used to secure the cam support section and the drive section next in place to each other and thus hold the clutch arrangement in engaged state. A suitable push-type ejection means permits the separation of the conical connection as desired. Alternatively, the clutch arrangement may be configured as a positive denture clutch. 
   Additional details of advantageous embodiments of the invention are obvious from the subclaims, the drawings and/or the description. 
   The drawings show exemplary embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic illustration of a heald shaft with drive rod assembly and shaft transmission. 
       FIG. 2  is a perspective illustration of the shaft transmission in accordance with  FIG. 1 , with the hood removed. 
       FIG. 3  is a longitudinal section of a first embodiment of a shaft arrangement associated with the shaft transmission in accordance with  FIG. 2 . 
       FIG. 4  is a longitudinal section of a second embodiment of a shaft arrangement for the shaft transmission in accordance with  FIG. 2 . 
       FIG. 5  is a schematic side elevation of a transmission arrangement consisting of a cam disk and disk followers in order to drive a rocker. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates an arrangement that is associated with a weaving machine and consists of a heald shaft  1 , a rod assembly  2  disposed to drive said shaft, and of a shaft transmission  3 . The shaft transmission  3  has a rocker  4  for each heald shaft that is to be driven, said rocker, as is indicated by the arrow  5 , performing a rocking back-and-forth motion that is transmitted to the heald shaft  1  via the rod assembly  2 . The shaft transmission  3  derives this rocking motion from the uniformly rotating motion of a drive shaft  6  that is connected with an electric motor that is not further illustrated. The electric motor may be a separate motor that only drives the shaft transmission  3  or the main drive of the weaving machine. As is also obvious from  FIG. 2 , said motor drives a shaft arrangement  8  via a gear mechanism  7 , for example, as in  FIG. 3 . The drive shaft  6  and the shaft arrangement  8  are rotatably supported in a transmission frame  9 , as is illustrated with the hood removed by  FIG. 2 . 
   The gear mechanism  7  is configured as a bevel gear transmission. It has a crown wheel  10  that is non-torsionally connected with the shaft arrangement  8 . Said crown wheel meshes with a pinion  11  that is non-torsionally connected with the drive shaft  6 . 
   Preferably two bearing arrangements  12 ,  13  are provided for supporting the shaft arrangement  8 . These bearing arrangements are preferably configured as rolling bearings that are arranged in appropriate walls  14 ,  15  of the transmission frame  9 , said walls preferably being aligned parallel to each other. The bearing arrangement  12  is preferably configured as a ball bearing, while the bearing arrangement  13  may preferably be a needle or roller bearing. Whereas the bearing arrangement  14  in the essentially flat wall  15  may be arranged so as to terminate flush on both sides, the wall  14  has a tubular flange  16  preferably projecting in the direction toward the crown wheel  10 , said tubular flange bearing on its end facing the crown wheel  10  the ball bearing of the bearing arrangement  12 . In so doing, the bearing arrangement  12  secures the axial position of the shaft arrangement  8  and thus of the crown wheel  10  and, therefore, defines the gear play of the gear mechanism  7 . 
   As illustrated by  FIG. 3  with reference to an example, the shaft arrangement  8  is divided. Said arrangement comprises a drive section  17  and a cam support section  18 , which, in operative state, are connected to each other in a non-torsional, non-bendable and axially rigid manner via a clutch arrangement  19 , whereby both are arranged coaxially with respect to an axis of rotation  20  defined by the bearing arrangements  12 ,  13 . 
   The drive section  17  is screwed to the crown wheel  10 . As shown by  FIG. 3 , this is achieved with the use of washers  21 , a locating cone  22 , several screws  23  and a clamping element  24 . Said elements are used to non-torsionally clamp the crown wheel  10  to the drive section  17 . In so doing, a pressure sleeve  25  supports on its outside circumferential surface the ball bearing of the bearing arrangement  12 , whereby the internal ring of the latter is accommodated between a radial flange of the pressure sleeve  25  and a screw ring  26  seated on the outside of the pressure sleeve  25 . The pressure sleeve  25  finds its axial abutment against a corresponding shoulder  27  of the drive section  17 . 
   The cam support section  18  of the shaft arrangement  8  supports on its outside circumferential surface a package  28  of at least one, preferably several, cam disks  29  to  29   i , whereby these may be seated on a common support sleeve  30  in order to form a package. These cam disks are disposed to drive the rocker  4 , as well as the additional rockers  4   a  through  4   l . With the exception of the optionally individual form of the cam disks  29  or  29   a  through  29   i , the transmission arrangements consisting of the respective cam disks  29  through  29   i  and the rockers  4  through  4   l  are analogous.  FIG. 5  illustrates such a transmission arrangement  31  with reference to the example of the rocker  4  and the cam disk  29 . The cam disk  29 , which consists of two complementary disks  29 ′,  29 ″, is associated with two cam followers  32 ,  33  having the form of rollers whose parallel axes of rotation are supported on a rocker  34  and roll off the non-circular outside circumferential surface of the cam disk  29 . This cam disk rotates about the axis of rotation  20  that is oriented parallel to the axes of rotation of the cam followers  32 ,  33 . Attached to the jack  34  is the rocker  4  that performs a rocking motion corresponding to the radial displacement movement of the cam followers  32 ,  33  when the cam disk  29  is rotating. 
   As shown by  FIG. 3 , the package  28  is seated between two disks  35 ,  36  mounted to the support sleeve  30 . The cam disks  29  through  29   i  may additionally be connected to the support sleeve in fixed positions of rotation. To do so, the cam disks  29  through  29   i  can be positioned relative to each other by index bolts or other alignment means. In addition, said disks can be secured—by a denticulation profile, by index bolts or by other means—in a fixed position of rotation relative to the support sleeve  30 . In turn, the support sleeve  30  may be secured in a non-torsional manner on the cam support section  18  by using suitable means such as, for example, a tongue and groove connection, a denticulation profile, a clamping screw, a pin connection or the like. 
   The cam support section  18  of the shaft arrangement  8  is preferably a shaft with a central hollow-drilled shaft which extends through the bearing arrangement  13 . This section may bear an internal ring  37 , whereby the roller elements of the bearing arrangement  13  roll on said internal ring&#39;s exterior circumference. The internal ring  37  can be seated with minimal or no play, however in an axially shiftable manner, on the cam support section  18  and come into abutment with a radial collar  38  of the cam support section  18 . 
   The other end of the cam support section  18  is connected to the drive section  17 . To do so, said end is preferably conical, so that a cone  39  is formed. This cone fits into a conical cutout  40  on the end of the drive section  17 , said end being located away from the crown wheel  10  and—viewed from the perspective of the crown wheel—beyond the bearing arrangement  12 . The cone  39  and the cutout  40  are arranged coaxially relative to the axis of rotation  20  and form the clutch arrangement  19  that is configured as a cone clutch or as a tapered shaft connection. In engaged state, it results in a non-torsional and non-bendable connection of the drive section  17  and the cam support section  18  to each other. The cone clutch has the advantage that it can be connected, i.e., engaged, in any position of rotation of the drive section  17  relative to the cam support section  18 . If a specific position of rotation is to be pre-specified, it is also possible to provide a positive connection, which permits engagement only in a specific position of rotation. 
   In order to secure the cam support section  18  and the drive section  17  to each other a suitable locking means  41 , for example, in the form of a locking bolt  42  may be provided, said bolt extending through the central bore of the cam support section  18  and into a tapped blind hole  43 . The bolt  42  is tightened in the tapped blind hole  43  so that said bolt&#39;s head  44  exerts an axial pressure on the cam support section  18 , thereby clamping the cone  39  in place in the cutout  40 . 
   The embodiment in accordance with  FIG. 3  requires that the distance between the internal shoulder of the radial collar  38  and the end  45  of the drive section  17  correspond to the width of the package  28  and the width of the disks  35  and  36  and to the width of the internal ring  37 , so that the bolt  42  may clamp these components to each other. This is required when only one positive engagement exists between the cam disks  29  and the support sleeve  30 , i.e., then the cam disks  29  are slipped onto the support sleeve  30  without play. At the same time, the bolt  42  clamps the cam support section  18  with the drive section  17 —and thus the cam package  28 —in place. 
   Alternatively, as illustrated by  FIG. 4 , the end  46  of the cam support section  18  may terminate inside the internal ring  37 . Thus, said ring does not have a radial collar  38 . A clamping disk  47  is used to clamp the cam package  26  in place between the disks  35  and  36  and the internal ring  37 . To do so, said clamping disk is fixed, with the use of mounting means  48 , in the tapped holes  49  of the cam support section  18 . Apart from this, the above description applies accordingly while reference is made to the same reference numbers. 
   The in-so-far described shaft transmission  3  operates as follows: 
   During operation, the drive shaft  6  rotates the shaft arrangement  8  via the gear mechanism  7  and, with said shaft arrangement, the cam disks  29  through  29   i . Accordingly, the rockers  4  through  4   i  perform rocking motions that are transmitted to the corresponding heald shafts. 
   If the motion of one or more heald shafts is to be changed, the package  28  is exchanged. To so, the machine is stopped and the hood of the shaft transmission  3  is removed. Thereafter, the bolt  44  is released. If the cone  39  should become stuck in the cutout  40 , it is loosened. This is done with a suitable push-type ejection means. For example, the through-bore of the cam support section  18  may be provided with an internal thread into which a bolt may be screwed, said bolt coming into abutment with the tapered smooth end at the bottom of the tapped blind hole  43 . Alternatively, push-type ejection screws may be inserted into one or more tapped holes that extend parallel to the central bore through the cam support section  18 . Additional options for releasing a conical connection are familiar to the person skilled in the art. 
   After releasing the conical connection and thus the clutch arrangement  19 , the cam support section  18  can be pulled axially out of the bearing arrangement  13 . As a result of this, the package  28  is freed and can be laterally moved in one piece out of the intermediate space between the walls  14 ,  15 . 
   Referring to the exemplary embodiment illustrated by  FIG. 3 , the clutch arrangement  19  in the space, which is enclosed by the tubular flange  16 , is arranged between the package  28  and the crown wheel  10  outside the space enclosed by the package  29 . In so doing, the clutch arrangement  19  is preferably located, as illustrated, between the bearing arrangement  12  and the package  28 . 
   A shaft transmission  3  for a weaving machine comprises a shaft arrangement  8  that supports, on one end, a crown wheel  10  in order to drive the shaft arrangement  8 . The shaft arrangement  8  is supported by means of two bearing arrangements  12 ,  13 , between which a package  28  comprising the cam disks  29  through  29   i  is non-torsionally held on the shaft arrangement  8 . The part  18  of the shaft arrangement  8 , which supports the package  28 , is connected with the remaining part  17  of the shaft arrangement  8  via a clutch arrangement  19  that represents a separating point. The clutch arrangement  19  is configured, e.g., as a frictional clutch with a cone  39  and an appropriate cutout  40 , and is secured, in connected state, by means of a locking means  41  that is to be actuated from one end of the shaft arrangement  8 . For disassembly and replacement of the package  28 , the connection can be released and the cam disk section  18  can be removed from the shaft transmission  3 , while the drive section  17  remains in the shaft transmission  3 . Consequently, the package  28  can be exchanged as a whole, without requiring the disassembly of the gear drive that drives the shaft arrangement  8 . 
   It will be appreciated that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. 
   LIST OF REFERENCE NUMBERS 
   
     
       
         
             
             
           
             
                 
             
           
          
             
               1 
               Heald shaft 
             
             
               2 
               Rod assembly 
             
             
               3 
               Shaft transmission 
             
             
               4 
               Rocker . . . 4i 
             
             
               5 
               Arrow 
             
             
               6 
               Drive shaft 
             
             
               7 
               Gear drive 
             
             
               8 
               Shaft arrangement 
             
             
               9 
               Transmission frame 
             
             
               10 
               Crown wheel 
             
             
               11 
               Pinion 
             
             
               12 
               Bearing arrangement 
             
             
               13 
               Bearing arrangement 
             
             
               14 
               Wall 
             
             
               15 
               Wall 
             
             
               16 
               Tubular flange 
             
             
               17 
               Drive section 
             
             
               18 
               Cam support section 
             
             
               19 
               Clutch arrangement 
             
             
               20 
               Axis of rotation 
             
             
               21 
               Washers 
             
             
               22 
               Locating cone 
             
             
               23 
               Screws 
             
             
               24 
               Clamping element 
             
             
               25 
               Pressure sleeve 
             
             
               26 
               Screw ring 
             
             
               27 
               Shoulder 
             
             
               28 
               Package 
             
             
               29 
               Disk cam . . . 29i 
             
             
               30 
               Support sleeve 
             
             
               31 
               Transmission arrangement 
             
             
               32 
               Cam follower 
             
             
               33 
               Cam following 
             
             
               34 
               Rocker 
             
             
               35 
               Disk 
             
             
               36 
               Disk 
             
             
               37 
               Internal ring 
             
             
               38 
               Radial collar 
             
             
               39 
               Cone 
             
             
               40 
               Cutout 
             
             
               41 
               Locking means 
             
             
               42 
               Bolt 
             
             
               43 
               Tapped hole 
             
             
               44 
               Head 
             
             
               45 
               End 
             
             
               46 
               End 
             
             
               47 
               Clamping disk 
             
             
               48 
               Mounting means 
             
             
               49 
               (Screw) thread