Abstract:
The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere &amp; Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere &amp; Company or otherwise.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    In the course of rationalization of the harvesting operation, agricultural implements with large operating widths are applied in conjunction with correspondingly high powered tractors. This applies particularly to mowing machines, for the mowing of grass and other grain crops, such as, in particular, corn, that are applies as front attachment implements for a tractor equipped with a chopper. The rotating tools here consist of intake and mowing drums, with which the crop is mowed and subsequently conducted to the chopper. In this case the operating gearbox of the tractor that drives the drive arrangement for the intake and mowing drums is formed by the central gearbox or the mowing height gear box of the chopper. Such forage harvesters employ high-powered motors up to 500 PS (metric horsepower) where correspondingly high drive power must be applied to the intake and mowing drums that are employed as rotating tools, of which several may be arranged on both sides of the vertical longitudinal center plane of the machine. Since the intake and mowing arrangements operating as rotating tools form large masses that must be accelerated for the initial acceleration of the mower, the drive arrangement of the tools is equipped with at least one slipping clutch as initial acceleration clutch and simultaneously as a safety clutch by means of which the torque transmitted between the drive shaft on the part of the vehicle and the drive arrangement of the rotating tools is limited in a manner known in itself.  
           [0002]    In practical application in operation of such large agricultural implements, it has been shown that the maximum torque that can be transmitted by the slipping clutch during initial acceleration of the machine is frequently exceeded, if the initial acceleration on the part of the tractor is performed with a wide open throttle, contrary to the operating instructions of the manufacturer of the machine, instead of gradually increasing the application of the accelerator or gas pedal. The slipping clutch then slips under certain circumstances for several seconds before a friction locking is established through the spring-loaded, ring-shaped friction disks. During the slippage periods, large amounts of heat is generated in the slipping clutches, which are usually configured as dry clutches, that lead to overheating of the friction surfaces, in particular if the initial acceleration, if necessary, must be repeated several times. The forces that can be transmitted by the clutch components are thereby continuously reduced so that the clutch can become inoperative after only a relatively short operating time.  
         SUMMARY OF THE INVENTION  
         [0003]    According to the present invention, there is provided an improved drive for a large mowing machine of the type described above.  
           [0004]    An object of the invention is to provide a drive having improved initial acceleration characteristics which are applicable for use in harvesting operations in machines of the type indicated above.  
           [0005]    A more specific object of the invention is to provide a drive embodying a slip clutch having a first section in the form of a hub configured as a ring-shaped container filled with fluid, with ring-shaped friction disks being engaged with end plates forming part of the container and mounted on a second clutch section for rotation with the second section which defines a housing surrounding the container, the fluid acting to absorb heat so that over-heating of the friction disks due to improper performance of the starting or initial acceleration process of the implement is largely avoided. The cooling fluid, such as water, contained in the ring-shaped container not only absorbs the heat generated by the clutching process, but conducts it to the surroundings over heat exchange surfaces provided by the ring-shaped container. In this way a considerable increase in the durability of the slip clutch is attained. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1 is a plan view of a machine for mowing corn and similar stalk-like crop in connection with a chopper.  
         [0007]    [0007]FIG. 2 is an enlarged, partial section of a plan view of the region of the drive arrangement of the mowing machine of FIG. 1.  
         [0008]    [0008]FIG. 3 is an enlarged, axial sectional view through a detail of the drive arrangement according to FIG. 2. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0009]    Referring now to FIG. 1, there is shown an agricultural implement in the form of a mowing implement or machine  1  attached to a tractor or similar self-propelled vehicle, here shown as a self-propelled forage harvester  2 , for the mowing of corn and similar stalk-like crops. The forage harvester  2  includes a chopper  3  that is arranged centrally with respect to the mowing implement  1 . The cut crop is conducted over intake rolls to a chopper blower, not shown in any further detail, in which it is chopped into short lengths and then conveyed over an exhaust duct  4  to a mobile container such as an agricultural self-loading forage box, for example.  
         [0010]    The mowing machine  1 , is moved forward by the vehicle  2  in the direction of operation or driving according to the arrow F, and, in the embodiment shown, includes a total of ten rotating tools in the form of intake and mowing drums  5  through  14 , respectively, with the drums  5  through  9  being arranged at the left side of a vertical, longitudinal center plane  15  of the machine, and the drums  10  through  14  being arranged at the right side of the center plane  15 . The two groups of intake and mowing drums  5  through  9 , on the one hand, and  10  through  14 , on the other hand, are arranged in a mirror image symmetrically about the longitudinal center plane  15 . In addition, further conveyor drums  16 ,  17  and  18  are located behind the neighboring intake and mowing drums  6  through  9  for further conveying of the crop cut by these drums and the drum  5  as well, while further conveyor drums  19 ,  20  and  21  are located behind the neighboring intake and mowing  10  through  13 , for further handling of the crop cut by these drums and the drum  14  as well.  
         [0011]    For driving the rotary tools in the form of the intake and mowing drums  5  through  14  as well as the conveying drums  16  through  21 , the mowing machine  1  is equipped with a drive arrangement, designated in its entirety by the numeral  22 , coupled to a gearbox  23  on the part of the vehicle that, in the embodiment shown, is formed by the central or mowing height gearbox of the chopper  3 . From the operating gearbox  23 , the drive is transmitted over an articulated shaft  24  to a gearbox  25  and from this over an articulated shaft  26  to the drive arrangement  22 .  
         [0012]    In the embodiment shown, the drive arrangement  22  includes a clutch arrangement acting as a safety device while transferring torque during initial acceleration, the clutch arrangement being in the form of two clutches  27  and  28  that are rigidly connected with each other over a connecting shaft  29  with sleeve couplings  30 . The two clutches  27  and  28  are configured identically and are arranged as mirror images symmetrically to each other on opposite sides of the vertical longitudinal center plane  15 . The clutches  27  and  28  are respectively connected with angled gear boxes  31  and  32  that transmit the drive taken from the tractor  2  to respective shaft drive-lines (not shown) supported in bearings, free to rotate, in a frame tube  33  for the drive of the left half of the machine with the intake and mowing drums  5  through  9 , or the right half of the machine with the intake and mowing drums  10  through  14 . For its part, the frame tube  33  is fastened to a base frame of the mowing machine  1  in a manner not shown in any further detail. Furthermore, as can be seen in FIG. 2, a shaft section  34  of the articulated shaft  26  continues through the gear box  31  and extends at  34   a  into the clutch  27  in which it is retained by a multi-edge connection  35  with an axial play for movement.  
         [0013]    Since the two clutches  27  and  28  are identical in design, their configuration shall be explained in greater detail below only on the basis of the clutch  27  together with the enlarged view in FIG. 3. Accordingly, the clutch  27  includes a first section defining a first clutch hub configured as a container  38  enclosed on all sides that includes an inner sleeve  39  providing a hub opening  36  that accepts the stub shaft  34 a of the drive shaft section  34  on the part of the vehicle introduced into the clutch  27 . The container  38  also includes an outer sleeve or cylindrical wall  40  that is joined to opposite end plates  43  and  44  so as to define an annular, space  41 , that is filled with cooling fluid, such as water, and is closed on all sides except for a fill opening provided in the outer sleeve  40 , which opening is closed after completion of the filling process by a threaded plug  42  with a sealing ring so that the space  41  is fluid tight.  
         [0014]    The clutch  27  further includes a second section in the form of a clutch housing  37  including an end plate or hub  58  having an opening  59  provided with internal splines or a multi-wedge connection  60  through which the drive connection to the angled gearbox  31  is made for driving the rotary tools on that side of the vehicle.  
         [0015]    Respectively located on the outside of the end faces  43  and  44  of the container  38  are ring-shaped or annular friction disks  45  and  46  that are respectively rigidly connected with ring-shaped or annular driver disks or backing plates  47  and  48 . The rigid connection of the ring-shaped disks  45  and  46  with the ring-shaped driver disks  47  and  48  can be performed by mechanical connecting links, by bonding, by spraying with friction disk material or any other appropriate manner. The clutch housing  37  is configured so as to define a cylindrical enclosure  50  that encompasses the container  38 . Guide sockets or tabs  49  form part of and are angled at right angles from the remaining portions of the disks  47  and  48  and are retained in circumferential guide slots provided in the cylindrical enclosure  50  so as to extend parallel to the axis of rotation and to provide axial play for the disks  47  and  48 . Otherwise, the sleeve enclosure  50  is configured as a grating with openings  51 , that improve the dissipation of heat from the ring-shaped container  38 .  
         [0016]    The friction disks  45  and  46  are spring loaded for effecting a drive connection that is a function of the torque between the ring-shaped container  38  forming the clutch hub and the clutch housing  37 . This spring loading is provided by a ring-shaped spring package  52 , inserted into the clutch housing  37 , which consists of a ring of individual helical compression springs  53  whose line of force is parallel to a rotational axis R of the clutch. The ring of springs  53  are supported at their opposite end faces respectively by retaining rings  54  and  55 , with the ring  54  bearing against the friction disk drive plate  48 .  
         [0017]    The compression of the compression springs  53  and thereby the maximum torque controlled by the contact pressure of the friction disks  45  and  46  at which the clutch  27  slips is adjusted by an adjustment ring  56  that is provided with detent cams  57  for a locking engagement in aperture openings of the clutch housing  37 . Here, two or several rings and aperture openings are preferably provided that are spaced from one another in the direction of the clutch axis R, that are spaced for their part in the circumferential direction corresponding to the detent cams  57  of the adjustment ring  56 . In the installed condition, the adjustment ring  56  is positioned with its inner end in contact with an outer face of the retaining ring  55 , and thereby determines in the installed condition the pressure force, depending on which aperture opening engages a locking cam  57 . As long as an adjustment of the torque through the package of compression springs  52  can be omitted, obviously a single ring of aperture openings in the clutch housing  37  would be sufficient for the locking of the adjustment ring  56 .  
         [0018]    The end plate or hub  58  of the housing  37  is located on the opposite end of the housing from the adjustment ring  56  and, together with the end plate  43  of the container  38 , sandwiches the backing plate  47  with the friction disk  45 . With the container  38  being mounted for shifting axially relative to the housing  37 , the force exerted by the compression springs  52  acts to establish the predetermined force of frictional engagement between the friction disk  45  and the container end plate  43 .  
         [0019]    At its end opposite the introduction opening for the stub drive shaft  34   a,  the inner sleeve  39  is rigidly connected, for example welded to a coaxial stub shaft  61 . Furthermore, the stub shaft  61  is rigidly connected or welded to the end face  44  of the ring-shaped container  38 . The same goes for the end face  43  with respect to the inner sleeve  39 . The stub shaft  61  extends through the spring package  52  to the connecting shaft  29 , with which it is connected over the sleeve coupling  30 . The connection with sleeve coupling  30  is again performed by a multi-wedge or spline connection.  
         [0020]    Furthermore, an arrangement of the grooves and ribs  62  can be seen in FIG. 3 that is limited to the central region of the sleeve bore  36  which is configured for the multi-wedge connection  35  (FIG. 2) with the correspondingly configured stub shaft  34   a  of the shaft section  34 .  
         [0021]    When the arrangement is coupled, the power flows over the spring loaded friction disks  45  and  46  from the ring-shaped container  38 , set into rotation by the drive shaft section  34 , to the clutch housing  37 , in particular, the end face or hub  58  whose rotational movement is transmitted in turn through the multi-wedge connection  60  to the gearbox  31 . Here the rotational drive is transmitted simultaneously over the stub shaft  61  to the connecting shaft  29  and from there over the stub shaft  61 ′, that corresponds to the stub shaft  61 , to the ring-shaped container  38 ′ and the clutch housing  37 ′ of the clutch  28  over the multi-wedge connection  60 ′ to the angled gearbox  32 .  
         [0022]    If during the operation of the clutch  27 , the pre-determined torque is exceeded, then the clutch slips, and a relative rotational movement occurs between the clutch housing  37  and the ring-shaped container  38  with sliding friction at the interface between the ring-shaped disks  45  and  46  and the end face walls  43  and  44 , respectively, of the ring-shaped container  38 . The relative rotational movement is made possible by the clutch housing  37  with its sleeve enclosure  50  that concentrically surrounds and is spaced from the ring-shaped container  38  so as to leave a circumferential ring shaped void  63 . It will be appreciated that heat generated at the interface of the clutch friction disks  45  and  46  and the container end faces  43  and  44  will be dissipated by the liquid coolant carried inside the container  38 . Further, the various slots or openings  51  in the enclosure  50  also help in the dissipation of heat generated when the clutch  27  slips.