Patent Publication Number: US-2023132573-A1

Title: Device for adjusting a sprocket of a chain drive

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of German Patent Application DE 102021128386.8 filed on Oct. 29, 2021, and German Patent Application DE 102021128389.2 filed on Oct. 29, 2021, the disclosures of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The disclosure generally relates to a sprocket adjuster for a chain drive, in particular for a chain drive for driving pressing rollers or pressing belts of a round baler for pressing crops. 
     BACKGROUND 
     The prior art discloses a multiplicity of round balers, with a distinction being drawn between round balers having a fixed pressing chamber and round balers having a variable pressing chamber. Round balers having a fixed pressing chamber are distinguished by the fact that a plurality of pressing rollers are arranged over the circumference of a defined cylindrical pressing chamber and delimit the pressing chamber in a circumferential direction. The cylindrical pressing space is delimited at the end sides by respective side walls. By contrast, round balers having a variable pressing chamber are distinguished by the fact that the cylindrical pressing space is delimited in the circumferential direction by one or more pressing belts, with the pressing belt being guided over a plurality of rollers. The circumference of the pressing space is configured to be variable by positionally changing one or more rollers during the pressing operation. The cylindrical pressing space is likewise delimited at the end sides by respective side walls. It is also known that both the pressing rollers of a round baler having a fixed pressing chamber and the rollers of a round baler having a variable pressing chamber can be driven or caused to rotate via a chain drive. Such chain drives are arranged on a frame of the round baler on one or both side walls outside of the pressing space. Here, the chain drive comprises a plurality of toothed wheels or sprockets which are connected to the pressing rollers or to rollers, with the sprockets being in drive connection via one or more drive chains. 
     Such a round baler is known from DE 196 32 762 A1, for example. A drive device for the pressing rollers, which delimit a pressing chamber, of a round baler is shown therein, with a plurality of chain drives being provided. The individual chain drives each serve for driving a partial number of the overall pressing rollers to be driven, with drive sprockets for driving the individual chain drives being able to be driven jointly. The sprockets intended for driving the pressing rollers are arranged on a circular arc in a lateral housing part of the round baler and the chain drives are mounted parallel to one another. 
     A further round baler from the prior art is shown in EP 2 952 089 A1, in which a plurality of pressing rollers are arranged around a pressing chamber and bear sprockets driven by a chain drive with a common chain. At least one of the sprockets and the associated pressing roller have interacting guide means, in the form of a shaft external toothing on the pressing roller and a hub internal toothing, interacting therewith, on the sprocket, which connect the sprocket and the pressing roller in a form-fitting manner in a direction of rotation and allow a movement of the sprocket in the axial direction of the pressing roller. Also provided are means for fixing the axial position of the sprocket in the form of a shaft nut, which is fastened to the pressing roller stub, and an external toothing engaging therewith. The configuration of the pressing rollers and sprockets that is disclosed here is suitable for drive-transmitting sprockets, but proves to be cost-intensive and complicated to manufacture. However, it does not satisfy the requirement of axial adjustability of the sprockets for the purpose of fine adjustment within the chain drive. 
     In the case of the aforementioned chain drives, it is customary for the chain to be guided from a drive sprocket to the sprockets which are to be driven of the pressing rollers, with, on the one hand, a chain guide with a plurality of windings and loop-like guidance of the chain being required, in particular to allow pivoting of the pressing rollers in order to open the pressing chamber. On the other hand, such a chain drive has to be held in tension. To make this possible, a chain drive of the aforementioned type has, in addition to the sprockets to be driven, further sprockets arranged therein which, within the chain drive, for the purpose of the aforementioned chain guidance, serve as deflection sprockets or guide sprockets and/or as sprockets for tensioning the chain drive. These further sprockets are freewheeling and are usually guided on a rotary bearing which is mounted on a bearing journal, which extends from the frame of the round baler, or is mounted on a bearing journal of a chain-tensioning device. Such freewheeling sprockets must also be subject to axial fine adjustment in order to lie precisely in the run of the chain. The fine adjustment of the sprockets mounted on the bearing journals usually occurs by means of spacer disks which are mounted on both sides of the end sides of the rotary bearing on the bearing journal, as is known, for example, from the mountings of the chain drives on a John Deere round baler of the F441 R type. This method of axial fine adjustment often proves to be very time-consuming and can occasionally require the multiple mounting and demounting of the sprocket on the bearing journal. The application of the above-described solution for fine adjustment of driven sprockets is unsuitable or not practicable for the axial fine adjustment of a freewheeling sprocket guided on a rotary bearing. 
     SUMMARY 
     According to the disclosure, a device or sprocket adjuster of the type stated at the outset is formed in such a way that a stop is formed on the bearing journal and at least one spring element is arranged between the rotary bearing and the stop, wherein a clamp is arranged which preloads the rotary bearing against the spring element. The arrangement of a spring element between the stop and the rotary bearing on the one hand and also the arrangement of the clamp which preloads the rotary bearing against the spring element allows precise axial displacement of the rotary bearing by means of simple adjustment of the clamp. The clamp is preferably arranged on the free end of the bearing journal and brace the rotary bearing against the spring element. The spring element preferably takes the form of a compression element which builds up a spring tension by means of compression. The preloading which can be set by the clamp on the spring element is preferably chosen in such a way that the range of flexibility or the deformation of the spring element is not completely used up, but a certain spring tension has been built up. This results in the fact that, by increasing the preloading, the rotary bearing is moved further in the direction of the spring element or in the direction of the fixed end of the bearing journal. By reducing the preloading, on the other hand, the rotary bearing is moved by the spring element in the direction of the free end of the bearing journal. Axial fine adjustment of the sprocket is thus made possible regardless of a thickness of a spacer disk. There is no need for laborious demounting of the sprocket or of the rotary bearing from the bearing journal in order, for example, to place a thicker or thinner spacer disk between the sprocket and frame. 
     The stop can be formed on the fixed end of the bearing journal, that is to say that it can be formed by the bearing journal-carrying component itself. In this case, the spring element would, on the one hand, be supported against the bearing journal-carrying component and, on the other hand, against the rotary bearing if no further components, such as, for example, spacer sleeves or spacer disks, are arranged between the spring element and the stop or the rotary bearing. 
     However, the stop is preferably defined by a shaft shoulder which is incorporated on the bearing journal between the rotary bearing and the fixed end. In this case, the spring element is supported against the shaft shoulder if no further components, such as, for example, spacer sleeves or spacer disks, are arranged between the spring element and the shaft shoulder or the rotary bearing. 
     The stop may, for example, also be formed by a snap ring which is held in an annular groove formed on the bearing journal between the rotary bearing and the fixed end. 
     It is also possible for the stop to be formed by a threaded nut which is arranged on an external thread formed on the bearing journal between the rotary bearing and the fixed end of the bearing journal. There would thus be provided an adjustable stop, with the result that the axial adjustment travel of the rotary bearing or of the sprocket is additionally variable by adjusting the threaded nut. 
     The clamp may comprise a clamping plate fastened to the free end of the bearing journal, wherein the rotary bearing is clamped on the bearing journal between the clamping plate and the spring element. The clamping plate may, for example, be fastened to the free end of the bearing journal by means of a clamping screw, wherein the clamping screw is received by an internal thread formed on the free end of the bearing journal. The rotary bearing is thus clamped on the bearing journal between the shoulder or spring element and the clamping plate. 
     The clamp may alternatively comprise a threaded nut arranged on an external thread at the free end of the bearing journal, wherein the rotary bearing is clamped on the bearing journal between the threaded nut and the stop or spring element. 
     The clamp may further comprise one or more spacer elements which are arranged between the clamping plate and the rotary bearing or between the threaded nut and the rotary bearing. The stated spacer elements make it possible for the device to be adapted to the size of the rotary bearing and also to the geometry of the spring element. The spacer elements can take the form of a bush, sleeve or disk. 
     The spring element preferably takes the form of a cup spring. Here, one or more cup springs arranged in a row can be provided in order to optimize the spring travel and/or the spring tension. Instead of cup springs, there can also be used other spring elements which produce a spring tension by means of compression. 
     The above-described device or sprocket adjuster is particularly suitable for use in a chain drive for driving pressing rollers or pressing belts of a round baler for pressing crops. Here, the device can be used on one or more sprockets of the chain drive. 
     The aforementioned chain drive is able to be used in a wide variety of types of agricultural machines in which rolls, rollers, drums or other rotating bodies have to be driven. However, it is particularly suitable for use in a round baler having a frame, a pressing space and pressing rollers or pressing belts which are arranged on the frame and surround the pressing space and are intended for pressing crops, wherein the chain drive is arranged on the frame and/or a side wall of the round baler for driving the pressing rollers or the pressing belt. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic side view of a round baler having a chain drive for driving pressing rollers. 
         FIG.  2    is a schematic cross-sectional view of a sprocket adjuster for adjusting a sprocket of the chain drive from  FIG.  1   . 
         FIG.  3    is a schematic cross-sectional view of an alternative form of a device for adjusting the sprocket of the chain drive from  FIG.  1   . 
         FIG.  4    is a schematic cross-sectional view of a further alternative form of the sprocket adjuster for adjusting the sprocket of the chain drive from  FIG.  1   . 
         FIG.  5    is a schematic cross-sectional view of a further alternative form of the sprocket adjuster for adjusting the sprocket of the chain drive from  FIG.  1   . 
         FIG.  6    is a schematic cross-sectional view of a further alternative form of the sprocket adjuster for adjusting the sprocket of the chain drive from  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions. 
     Terms of degree, such as “generally”, “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of a given value or orientation, for example, general tolerances or positional relationships associated with manufacturing, assembly, and use of the described embodiments. 
     As used herein, “e.g.” is utilized to non-exhaustively list examples, and carries the same meaning as alternative illustrative phrases such as “including,” “including, but not limited to,” and “including without limitation.” As used herein, unless otherwise limited or modified, lists with elements that are separated by conjunctive terms (e.g., “and”) and that are also preceded by the phrase “one or more of,” “at least one of,” “at least,” or a like phrase, indicate configurations or arrangements that potentially include individual elements of the list, or any combination thereof. For example, “at least one of A, B, and C” and “one or more of A, B, and C” each indicate the possibility of only A, only B, only C, or any combination of two or more of A, B, and C (A and B; A and C; B and C; or A, B, and C). As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, “comprises,” “includes,” and like phrases are intended to specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. 
     Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a round baler is generally show at  10  in  FIG.  1   . The round baler  10  includes a front part  12  and a rear part  14 . 
     The round baler  10  further includes a frame  16 , a running-gear unit  18 , a drawbar  20 , side walls  22  on the front part  12 , side walls  23  on the rear part  14 , pressing rollers  24  on the front part  12 , pressing rollers  26  on the rear part  14 , a feed assembly  28  for receiving a crop, and a drive device  30 . 
     The frame  16  consists of struts and the like which hold together and support the aforementioned components and thus form the front part  12  into a unit 
     The running-gear unit  18  is composed, in a manner which is not indicated in more detail, of an axle and of wheels mounted thereon which are situated in the lower rear region of the front part  12  and support the entire round baler  10  such that it can move on the ground. 
     The drawbar  20  serves for connecting the round baler  10  to a towing vehicle, for example to an agricultural tractor, and is fixedly connected to the frame  16 . 
     The side walls  22 ,  23  are also fixedly connected to the frame  16  and terminally close off a pressing chamber  32 . For this purpose, the side walls  22 ,  23  assume a distance from one another and movably receive the pressing rollers  24  and  26 . In the upper rear region of the front part  12  there is provided a bearing (not shown) which serves for the vertically pivotable connection of the rear part  14 . The side walls  22 ,  23  are connected to one another by cross-struts, which are not indicated in further detail but are sufficiently well known. 
     The pressing rollers  24  and  26  are composed in a known manner of a sheet-metal shell and of a shaft or shaft stubs. The center points of the pressing rollers  24  and  26 , that is to say their axes of rotation, are situated substantially on a part of a circle which surrounds the pressing chamber  32 . On at least one side of the round baler  10 , on the outer side of the side walls  22 ,  23 , sprockets  34  are provided on the pressing rollers  24  at the front part  12 , and sprockets  36  are provided on the pressing rollers  26  at the rear part  14 . The sprockets  34  of the pressing rollers  24  are surrounded by a drive chain  38  of a first chain drive  40 . The sprockets  36  of the pressing rollers  26  are surrounded by a drive chain  42  of a second chain drive  44 . A further drive chain  46  of a third chain drive  48  serves for driving the first and second chain drive  40  and  44 . The third chain drive  48  is driven by a main drive sprocket  50  which is connected to the drive device  30 . The third chain drive  48  drives a first drive sprocket  52  which serves for driving the first chain drive  40 . The third chain drive  48  additionally also drives a second drive sprocket  54  which serves for driving the second chain drive  44 . The first and second drive sprocket  52  and  54  are each double-toothed, with a first toothing of the first drive sprocket  52  and a first toothing of the second drive sprocket  54  being connected to the third chain drive  48 . A second toothing of the first drive sprocket  52  is connected to the first chain drive  40  and drives the latter. A second toothing of the second drive sprocket  54  is connected to the second chain drive  44  and drives the latter. 
     The drive device  28  is, in a manner which has not been shown, fed by the towing vehicle, for example via an articulated shaft, and contains a transversely extending shaft  56  in the rear region of the drawbar  20 . Emanating from the shaft  56  is the main drive sprocket  50  which drives the third chain drive  48 . 
     The chain drives  40 ,  44  and  48  are guided over additional sprockets  58 ,  60 ,  62 ,  64  and tensioned by means of tensioning devices, which are not indicated in more detail. Furthermore, a sprocket  66  is provided for the first chain drive  40  and a sprocket  68  is provided for the second chain drive  44  for guiding or deflecting the respective drive chains  38 ,  42 . 
       FIGS.  2  to  6    each show sprocket adjusters or devices  70  for adjusting the additional sprockets  58 ,  60 ,  62 ,  64 ,  66  and  68 , with the sprockets  58 ,  60 ,  62 ,  64 ,  66  and  68  each being arranged on a bearing journal  72  of such a device  70 . In addition to the bearing journal  72  and one of the sprockets  58 ,  60 ,  62 ,  64 ,  66  and  68  to be adjusted, the device  70  comprises a rotary bearing  74 , which is arranged on the bearing journal  72 , and the sprocket  58 ,  60 ,  62 ,  64 ,  66  and  68  guided on the rotary bearing  74 . The bearing journal  72  comprises a free end  76  and a fixed end  78 . The latter is fastened to the frame  16 , to the side walls  22 ,  23  or to a tensioning arm  80  of a tensioning device (not indicated in more detail). The fastening of the bearing journal  72  can occur in a demountable (releasable) manner in any desired form or in a non-releasable manner, for example by means of welding or by means of a connection produced in the casting or forging process of the tensioning arm  80 . The bearing journal  72  has a stop  82  which can be formed in a variety of ways, as illustrated in  FIGS.  2  to  5   . 
     According to  FIG.  2   , the stop  82  is formed by the component carrying the bearing journal, here the frame  16 , the side walls  22 ,  23  or the tensioning arm  80  of a tensioning device. 
     According to  FIG.  3   , the stop  82  can also be formed by a shaft shoulder  84  formed on the bearing journal  72 . 
     According to  FIG.  4   , the stop  82  is formed by a threaded nut  86  which is guided on an external thread region  88  on the bearing journal  72  between the rotary bearing  74  and the fixed end  78  of the bearing journal  72 . 
     According to  FIG.  5   , the stop  82  is formed by a snap ring  90  which is guided in an annular groove  92  on the bearing journal  72  between the rotary bearing  74  and the fixed end  78  of the bearing journal  72 . 
     As is shown in  FIGS.  2  to  6   , spring elements  94  in the form of cup springs are arranged between the rotary bearing  74  and the respective stop  82  and are supported, on the one hand, on the stop  82  and, on the other hand, on an end face  96  of the rotary bearing  74  that faces the fixed end  78  of the bearing journal  72 . 
     On an opposite end face  98  of the rotary bearing  74  there adjoins a spacer element  100  which is pressed by a clamping plate  102  against the end face  98  of the rotary bearing  74 . The clamping plate  102  is held by a clamping screw  104  or pressed against the spacer element  100 . The clamping screw  104  is guided in an internal thread  106  formed on the free end  76  of the bearing journal  72 . 
     According to  FIGS.  2  to  5   , preloading means via a clamp  107  is thus provided by the internal thread  106 , the clamping screw  104 , the clamping plate  102  and the spacer element  100 . The rotary bearing  74  is clamped between the spacer element  100  and the spring element  94  and preloading is produced by clamping the clamping screw  104  against the clamping plate  102  or against the spacer element  100  in collaboration with the spring element  94  or with compression of the cup springs. Depending on the degree of clamping, the rotary bearing  74  is moved axially in the one or the other direction along the bearing journal  72 , with the degree of clamping or the preloading being variable by screwing in or unscrewing the clamping screw  104  and it thus being possible to bring about an axial adjustment of the rotary bearing  74  and of the sprocket  58 ,  60 ,  62 ,  64 ,  66 ,  68  guided thereon. 
     In an alternative embodiment, which is depicted in  FIG.  6   , the clamp  107  is provided, in relation to the internal thread  106 , the clamping screw  104  and the clamping plate  102  from  FIGS.  2  to  5   , by an external thread  108  formed on the free end  76  of the bearing journal  72  and by a threaded nut  110  guided thereon, with the spacer element  100  being pressed against the end face  98  by the threaded nut  110 . Here, the external thread  108 , in collaboration with the threaded nut  110  and the spacer element  100 , display the same technical effect as the above-described clamp  107  from  FIGS.  2  to  5   . 
     The spacer elements  100  shown in the exemplary embodiments are provided in the form of a spacer sleeve or a spacer bush. The spacer elements  100  can here also take the form of spacer disks or washers. Furthermore, it is by all means conceivable that spacer elements  100  are also provided between the spring element  94  and the end face  96  of the rotary bearing  74  or else the stop  82 . 
     In the case of the exemplary embodiment shown in  FIG.  4   , it is also conceivable that a spring element  94  is provided on the opposite end face  96  and that the preloading function is brought about by adjusting the threaded nut  86 . In such a case, the arrangement of a spring element  94  on the end face  98  could be dispensed with and optionally be replaced by a spacer element  100  on this side of the rotary bearing  74 . 
     The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed teachings have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims.