Patent Publication Number: US-2023133649-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 sprocket adjuster of the type stated at the outset is designed in such a way that the bearing journal has a first external thread region and a second external thread region. A threaded nut is arranged on each of the external thread regions and thereby the rotary bearing is clamped on the bearing journal between the external thread regions. The arrangement of threaded nuts axially on both sides of the rotary bearing allows precise axial displacement of the rotary bearing by means of simple rotation of the threaded nuts. Axial fine adjustment of the sprocket is 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. 
     A spacer element can be provided between a threaded nut and a corresponding end face side of the rotary bearing. The spacer element is placed between the threaded nut and the corresponding end side of the rotary bearing, with the result that the threaded nut does not come into direct contact with the rotary bearing. This avoids transmission of rotation to the threaded nut and loosening of the threaded nut as a result of vibration and rotational movements of the rotary bearing during operation. Moreover, it is possible by means of the spacer element, with the same configuration of the thread turns on bearing journals of the same length, for the axial rough positioning of the sprocket on the bearing journal to be configured to be very variable without having to excessively change the position of the threaded nuts. Consequently, the number of thread turns on the bearing journal, and hence also the manufacturing effort for the external thread on the bearing journal, can be minimized and an adjusting region can be variably configured. 
     A simple embodiment of a spacer element is represented by a bushing, sleeve or disk which is pushed onto the bearing journal and is clamped between the threaded nut and end side of the rotary bearing, on one side or else on both sides of the rotary bearing. A further embodiment provides the use of one or more cup springs which can serve as a spacer element, with these being able to be arranged in addition to or in place of the aforementioned spacer elements. One or more cup springs place the threaded nuts under a certain stress, with the result that an additional anti-rotation safeguard against loosening of the threaded nuts is created. Furthermore, it is thus also possible to achieve a spring-preloaded axial displacement of the sprocket if a cup spring is arranged only on one side of the rotary bearing. In this case, an adjustment of the threaded nut arranged on the opposite side of the cup spring brings about compression or expansion of the cup spring. Depending on the adjusting direction of the threaded nut, an associated increasing or decreasing spring tension causes an axial displacement of the rotary bearing on the bearing journal. Here, the described axial displacement of the rotary bearing can already be achieved by adjusting only one of the threaded nuts. 
     The diameter of the first external thread region is designed to be greater than the diameter of the second external thread region, wherein the second external thread region extends starting from the free end of the bearing journal, and the first external thread region extends between the fixed end and the rotary bearing. Different diameters of the external thread portions, starting from a smaller diameter at the free end of the bearing journal, allow mounting of the device just through access to the free end of the bearing journal. This makes possible a non-demountable fastening of the fixed end of the bearing journal to the frame of the round baler, for example by a welded connection or as a cast or forged part of a frame part of the frame. A bearing journal region without a thread, on which the rotary bearing is received, is preferably provided between the external thread regions of the bearing journal. Consequently, the bearing journal region on which the rotary bearing is received can be produced independently of the thread regions and with sizes differing therefrom in terms of diameter and can be tailored to an optimum snug fit for the rotary bearing. 
     In an alternative exemplary embodiment which displays the same technical effect of the device, an internal thread region, on which a clamping plate is fastened via a clamping screw, is provided in place of the second external thread region on the free end of the bearing journal and the associated threaded nut, wherein the rotary bearing is clamped on the bearing journal between the external thread region and the clamping plate. Consequently, the clamping function of the threaded nut on the second external thread region of the preceding example is replaced by the clamping plate. All further above-described embodiments can also be used in this alternative example. It is thus possible, for example, that in this case, too, a spacer element is provided between the threaded nut and/or the clamping plate and a corresponding end face side of the rotary bearing, wherein the spacer element can correspondingly also take the form of a bush, sleeve, disk or cup spring. 
     The above-described 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 the sprocket adjuster 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   . 
     
    
    
     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 shown at  10  in  FIG.  1   . Referring to  FIG.  1   , the round baler  10  includes a front part  12  and a rear part  14 . 
     The round baler  10  further comprises 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  30  is, in a manner which has not been shown, powered 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  5    each show sprocket adjuster 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 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  also has a first external thread region  82  and a second external thread region  84 , with the diameter of the first external thread region  82  being designed to be greater than the diameter of the second external thread region  84 . A first threaded nut  86  is screwed onto the external thread region  82 , and a second threaded nut  88  is screwed onto the second external thread region  84 . Between the first threaded nut  86  and an end face  90  of the rotary bearing  74  that faces it, there is provided a first spacer element  92  in the form of a spacer sleeve or spacer bush. Between the second threaded nut  88  and an end face  94  of the rotary bearing  74  that faces it, there is provided a second spacer element  96 , likewise in the form of a spacer sleeve or spacer bush. The spacer elements  92  and  96  can here also take the form of spacer disks or washers. 
     In an alternative embodiment, as shown in  FIG.  3   , the first spacer element  92  is replaced by a cup spring pair  98 . Here, one or more cup springs  98  can be arranged behind one another. Likewise, the second spacer element  96  could also be replaced by one or more cup springs  98 . 
     Further alternative embodiments are shown in  FIG.  4    or  FIG.  5   . Here, the second external thread region  84  and the second threaded nut  88  from  FIGS.  2  and  3    have been replaced by an internal thread region  100  which is provided on the free end  76  of the bearing journal  72  and which has a clamping screw  102  held therein and a clamping plate  104 . The internal thread on the internal thread region  100  in collaboration with the clamping screw  102  and the clamping plate  104  here display the same technical effect as the above-described second threaded nut  88  in collaboration with the second external thread region  84 , with the rotary bearing  74  being clamped on the bearing journal  72  between the first external thread region  82  and the clamping plate  104 . Consequently, the clamping function of the second threaded nut  88  on the second external thread region  84  of the preceding examples is replaced by the clamping plate  104 . All further above-described embodiments can also be used in this alternative example. It is thus possible, for example, as shown in  FIGS.  4  and  5   , that a spacer element  92 ,  96 ,  98  can, in this case too, be provided between the first threaded nut  86  and/or the clamping plate  104  and the corresponding end face  90 ,  94  of the rotary bearing  74 , with the spacer element  92 ,  96 ,  98  correspondingly also being able to take the form of a bush, sleeve, disc or cup spring. 
     By rotating the first and second threaded nuts  86 ,  88  or the first threaded nut  86  and the clamping screw  102  (in the case of the exemplary embodiment in  FIG.  4   ), the position of the rotary bearing  74  can be changed axially with respect to the bearing journal  72  and a fine adjustment of the rotary bearing, and hence of the axial position of the sprocket with respect to the bearing journal  74 , can be carried out. Should cup springs  98  be provided as spacer elements, it is possible, by virtue of the preloading applied by the cup spring  98 , to achieve an axial displacement of the rotary bearing  74  just by adjusting only one threaded nut  86 ,  88  or by adjusting only the clamping screw  102  (in the case of the exemplary embodiment in  FIG.  5   ). 
     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.