Abstract:
A support for an agricultural implement carried on a receiving device of an agricultural machine includes at least one support wheel connected with the receiving device. A support wheel assembly for use with the disclosed method includes a support wheel and a wheel lifting cylinder connecting the support wheel with the receiving device. The load on the support wheel is adjustable via the wheel lifting cylinder. Adjustment is controlled in response to load sensors.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to agricultural machinery and, more particularly, to a method and assembly for supporting an agricultural implement on an agricultural machine. 
     DESCRIPTION OF THE RELATED ART 
     German Patent No. 199 18 551 discloses a generic agricultural harvesting machine which is designed as a forage harvester and which at the front has an intermediate attachment which receives an agricultural implement. So the load of the agricultural implement does not have to be supported exclusively via the front axle of the carrier vehicle, associated with the intermediate attachment are support wheels which make it possible for at least part of the mass of the agricultural implement to be supported during road transport. Thus the front axle of the carrier vehicle does not have to support the whole load of the agricultural implement. Adaptation of the support wheels to the intermediate attachment of the agricultural machine does however require considerable reinforcement of this intermediate attachment, because when travelling over uneven terrain considerable shock loads can arise and have to be absorbed by the intermediate attachment. Because the axles of the support wheels are arranged directly on the intermediate attachment of the agricultural harvesting machine, a vertical movement of the support wheels relative to this intermediate attachment is not possible. As a result, when the intermediate attachment is raised the load transmitted by the support wheels to the ground gradually decreases and becomes equal to zero the moment the support wheels have lost contact with the ground. The decrease in support function of the support wheels when the intermediate attachment is raised therefore requires, in spite of the support wheel assembly, dimensioning of the axles of the agricultural harvesting machine according to the maximum possible load. 
     The present invention is directed to overcoming one or more of the problems set forth above. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is to provide a method and assembly for providing support for an agricultural implement carried on a receiving device of an agricultural machine. 
     Another aspect of the invention is to provide a system whereby one support wheel provides load relief on the axles of an agricultural harvesting machine, resulting in the ability to construct machines having axles that are less materially-intensive and, therefore, less expensive to manufacture. 
     In accordance with the above, there is provided a method for providing support for an agricultural implement carried on a receiving device of an agricultural machine that includes the steps of providing at least one support wheel connected with the receiving device and adjusting the load on the support wheel. In a preferred embodiment, the method also includes the step of providing a wheel lifting cylinder associated with each support wheel and the step of adjusting the load on the support wheel includes adjusting the position of the support wheel with the wheel lifting cylinder. In another preferred embodiment, the method further includes the steps of measuring the loads on a drive axle and steering axle of the agricultural harvesting machine and the step of adjusting the load on the support wheel includes adjusting the load on the support wheel as a function of the loads on the drive axle and the steering axle. 
     A support wheel assembly for use with the disclosed method includes a support wheel and a wheel lifting cylinder connecting the support wheel with the receiving device, wherein the load on the support wheel is adjustable via the wheel lifting cylinder. In a preferred embodiment, the wheel lifting cylinder adjusts the support wheel in a generally vertical direction. In another preferred embodiment, the assembly includes load-sensing transducers associated with a drive axle and steering axle of the of the agricultural machine and at least one electronic calculating unit in communication with the first and second load-sensing transducers and wherein the electronic calculating unit generates a control signal as a function of the loads on the drive and steering axles. 
     These aspects are merely illustrative of the innumerable aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made more particularly to the drawings which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views. 
     FIG. 1 is a side view of an agricultural harvesting machine embodying the present invention and incorporating a support wheel assembly. 
     FIG. 2 is a perspective view of an embodiment of a support wheel assembly. 
     FIG. 3 is a schematic view of one fluid powered control system for the support wheel assembly. 
     FIG. 4 is a schematic view of another fluid powered control system for the support wheel assembly. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates an agricultural harvesting machine in the form of a combine harvester  2 . The combine harvester  2  carries a receiving device  5  (shown as a feed rake in this embodiment) at its front end. The receiving device  5  carries an agricultural implement  13 , which is in the form of a grain header in the embodiment shown. The receiving device  5  is mounted on pivot shaft  3 , which is transverse to the direction of travel FR, thereby allowing the receiving device  5  to pivot in a vertical direction. Holding flanges  6  are integrally formed with the receiving device  5  on its lower side. The holding flanges  6  receive piston rods  8  of lifting cylinders  9  so that cylinders  9  are pivotable about an axis  7  pointing transversely to the direction of travel FR. The lifting cylinders  9  are mounted at and are pivotable about axis  10 , which points transversely to the direction of travel FR. By pressurizing the lifting cylinders  9  or relieving them of pressure, the piston rods  8  move out of cylinders  11  of the lifting cylinders  9  or enter them. This facilitates a pivot movement of the receiving device  5  in a vertical direction about the pivot shaft  3 . The lifting cylinders  9  also provide support for the receiving device  5 . 
     Referring to FIG. 2, support wheels  15  are connecting with the receiving device  5  at the region between the agricultural implement  13  and a front axle  14  of the machine  1  in order to provide additional support for the receiving device  5  and the agricultural implement  13 . Each support wheel is provided with a wheel axle  16 . A hub  17  surrounds the wheel axle  16 . A receiving flange  18  is integrally formed with the hub  17  at its inner end at the region of the support wheels  15 . A pivot shaft  20  passes through the receiving flange  18  and points in a vertical direction. In the embodiment shown, the pivot shaft  20  is an axially locked bolt  19 . The pivot shaft  20  also passes through a guide eye  22  at a rim region  21  of the support wheels  15 . A supporting arm  23  is attached to the other end of the guide eye  22 . In the embodiment shown, associated with each support wheel  15  is such a supporting arm  23 , wherein each supporting arm  23  includes a head piece  24  at its end receiving the respective support wheel  15 . An angle profile carrier  25  is welded to the head piece  24  at the carrier vehicle side. The angle profile carrier  25  has a cross-section increasing in the direction of the front axle  14  of the carrier vehicle  1 . 
     Holding flanges  26  are associated with the front side of the front axle  14  of the agricultural machine  1 . Shafts  28  pass through the holding flanges  26  (shown in this embodiment as axially locked bolts) and are transverse to the direction of travel FR. Flange-like extensions  29  of the angle profile carriers  25  traverse the gap between adjacent holding flanges  26  and are held in place by the shafts  28 . The angle profile carriers  25  are thereby pivotable in a vertical direction about shafts  28 . This arrangement forms a pivotable connection between the supporting arm  23  of support frame  30  and the front axle  14  of the agricultural harvesting machine  1 . 
     A holding strap  31  is formed integrally with the head piece  24  of the first supporting arm  23  on the side facing away from the respective support wheel  15 . The holding strap  31  receives the front end of a piston rod  32  of a lifting cylinder  33  so that it is pivotable about an axis  34  pointing transversely to the direction of travel FR. The cylinder end of the lifting cylinder  33  is attached to the receiving device  5  of the agricultural harvesting machine  1  so that it is pivotable about a shaft  35  also arranged transversely to the direction of travel FR. Thus the respective lifting cylinder  33  forms a further supporting arm  36  of the support frame  30 , which pivotably connects the support wheel  15  to the receiving device  5  of the agricultural harvesting machine  1 . In this way, each of the support wheels  15  is connected by a support frame  30  consisting of a first supporting arm  25  and at least one further supporting arm  36  to both the agricultural harvesting machine  1  and the receiving device  5 . 
     In an alternate embodiment, the support frame  30  is designed in one piece and is arranged on the agricultural harvesting machine  1  so that it is pivotable via one or more pivot axes  28  arranged transversely to the direction of travel FR. In other embodiments, the receiving device  5  is supported on the agricultural harvesting machine  1  by only one lifting cylinder  9  or any number of lifting cylinders  9 . 
     This arrangement permits the association of the support wheels  15  with the receiving device  5  can be varied in a vertical direction, so that the support wheels  15  can always touch the ground  36  irrespective of the position of the receiving device  5 . This construction makes it possible to adjust the support load F 1  of the at least one support wheel  15  to be supported on the ground  37 . It is within the scope of the invention that associated with the receiving device  5  are a plurality of support wheels  15  at least some of which transmit support loads F 1  adjustable by means of lifting cylinders  33  to the ground  37 . In one embodiment, the multiple support wheels  15  are adjustable independently of one another. A particularly advantageous embodiment of the support wheels  15 , which will be described in more detail below, is achieved if this adjustability of the support load F 1  also allows regulation of the bearing pressure p of the agricultural implement  13  on the ground  37 . 
     FIG. 3 illustrates a control system for one embodiment of a wheel support assembly. The lifting cylinder  33  of the support wheel  15  and the lifting cylinder or cylinders  9  of the receiving device  5  are single-acting lifting cylinders. A system conduit or pipe  38  connects the piston face side of the pressure chambers  39 ,  40  of the lifting cylinders  33 ,  9 , respectively. The system pipe  38  has at least one pressure-limiting valve  41  which limits the pressure in the system pipe  38  and, on exceeding the pressure threshold value P c  which is adjustable at the pressure-limiting valve  41 . The pressure-limiting valve is connected to the tank  42 , so that a portion of the energy-transmitting medium can run off into the tank  42 . It is contemplated that the parallel-connected pressure-limiting valve  41  can be replaced by a pressure-limiting valve  41   a  connected in series with the at least one lifting cylinder  9  of the receiving device  5  and which separates the lifting cylinder  9  of the receiving device  5  from the system pipe  38  as soon as the pipe pressure has reached the set value p c  Both embodiments create the possibility of limiting to a fixed value the support load F transmitted by the lifting cylinder or cylinders  9  of the receiving device  5  to the axle  14  of the agricultural harvesting machine. Thus, the support load F 2  at the axle  14  of the agricultural harvesting machine  1  can be limited to a fixed value. 
     So that the piston rod  8  of the lifting cylinders  9  can nevertheless retract when the pressure-limiting valve  41   a  is blocked, associated with the pressure-limiting valve  41   a  at its simplest is a non-return valve  41   b  which opens in the direction of an accumulator  76 . As a result, operationally related pressure peaks in the pressure chamber  40  on the piston side of the lifting cylinder or cylinders  9  of the receiving device  5  can be reduced even when the pressure-limiting valve  41   b  is closed. 
     A switchable 2/2-port directional control valve  43  is also connected to a pump P integrated in the agricultural harvesting machine  1  and to a tank T. Pressurization of the system pipe  38  causes the piston rods  8 ,  32  to extend out of the respective lifting cylinders  9 ,  33 . In the process the receiving device  5  performs a pivot movement about its upper pivot shaft  3  to a position removed from the ground. At the same time the at least one support wheel  15 , which is arranged on the receiving device  5  so as to be vertically movable by the other lifting cylinder  33 , moves towards the ground to ensure that the at least one support wheel  15  contacts the ground  37 . Because the lifting cylinders  9 ,  33  coupled together are single-acting, gravity-related lowering of the receiving device  5  simultaneously leads to also gravity-related retraction of the lifting cylinder  33  which receives the at least one support wheel  15  vertically movably. Such a design ensures that the ratio between the support load F 1  to be transmitted by the at least one support wheel  15  and the support load F to be transmitted to the land wheels  44  of the adjacent front axle  14  is constant. This ratio corresponds to the ratio of the piston faces A 1 , A 2  of the coupled lifting cylinders  9 ,  33 . 
     The lifting cylinders  9 ,  33  (which are single-acting in FIG. 3) can also be double-acting as shown in FIG.  4 . Here, the pressure chambers  39 ,  40  on the piston face side are connected by a pipe system  45  to each other and to an adjustable pressure-limiting valve  46 . The pressure chambers  47 ,  48  on the piston rod side of said lifting cylinders  9 ,  33  are also connected by a pipe system  49  to each other and to a pressure-limiting valve  50 . Both pressure-limiting valves  46 ,  50  correspond in function to the pressure-limiting valve  41  already described when using single-acting lifting cylinders  9 ,  33 . Via a 3/2-port directional control valve  51  the pipe systems  45 ,  49  and hence the lifting cylinders  9 ,  33  are connected to the pump P and the tank T of the agricultural harvesting machine  1 . When using double-acting lifting cylinders  9 ,  33  too, pressurization of the pressure chambers  39 ,  40  on the piston face side leads to lifting of the receiving device and lowering of the at least one support wheel  15 . Conversely, pressurization of the pressure chambers  47 ,  48  on the piston rod side of the lifting cylinders  9 ,  33  coupled together leads to lowering of the receiving device  5  with simultaneous lifting of the at least one support wheel  15 . With this design too it is ensured that the at least one support wheel  15  has permanent contact with the ground  37 , wherein here the support load ratios F 1 /F now depend on the ratio of the piston faces A 1  and A 2  and on the ratio of the piston faces A 3  and A 4  on the piston rod side. It is contemplated that accumulators  76  according to FIG. 3 can be associated with the pipe systems  38  or  45 ,  49 , to avoid sudden loading. 
     The support wheels  15  shown in FIG. 2 can also be pivotable about the vertical pivot shaft  20 , wherein the bolt  19  forming the pivot shaft  20  is encompassed at the top by a steering lever  52  with which is associated at one end a stud  53  pointing in a vertical direction. The supporting arm  23  which receives the respective support wheel  15  has, at its end associated with the front axle  14  of the agricultural harvesting machine  1 , a stud  54  pointing in a vertical direction. On the stud  54  is pivotably arranged an angle lever  55  with which are in turn associated non-rotatably a plurality of studs  56 ,  57 ,  58 . A first coupling rod  59  connects the stud  53  of the steering lever  52  pivotably to a stud  56  arranged on the angle lever  55 , wherein the coupling rod  59  extends in the direction of the front axle  14  of the agricultural harvesting machine  1  above and in the region of the angle profile carrier  25  of the respective supporting arm  23 . In the embodiment shown, associated with the adjacent support wheels  15  are steering levers  52 , coupling rods  59  and angle levers  55  which are arranged inversely symmetrically to each other and which in each case form a partial steering mechanism  60 ,  61  for the respective support wheel  15 . In the region of the front axle  14 , the two partial steering mechanisms  60 ,  61  are coupled to each other by a connecting strut  62  pivotably connected to the rear studs  57  of the angle levers  55 . Pivotably associated with one of the angle levers  55  via a further stud  58  is a steering cylinder  63  which at the other end is received by a holding flange  65  attached to the angle profile carrier  25 , so that it is also pivotable about a vertical axis  64 . By pressurization of the double-acting steering cylinder  63 , the piston rod  66  can be moved out of the steering cylinder  63  or into it, wherein the support wheels  15  perform pivot movements in the same direction about their vertical pivot shafts  20 . It is within the scope of the invention that only one support wheel  15  which is steerable according to the invention or a plurality of support wheels  15  which are steerable according to the invention are associated with the agricultural harvesting machine  1  or, if there is more than one support wheel  15 , only some of the support wheels  15  are steerable. Also, the steering movement of the steered axle  67  of the agricultural harvesting machine  1  with its land wheels  68  and the steering movement of the support wheels  15  according to the invention can be coupled to each other. 
     The agricultural harvesting machine  1  should be steered and driven reliably. Accordingly, as shown in FIG. 1, associated with each axle  14 ,  67  of the agricultural harvesting machine  1  is at least one load-sensing transducer  69 ,  70  which is, for example, a wire strain gauge for determining the deflection of the axles  14 ,  67  or a pressure sensor for determining the tire pressure of the land wheels  44 ,  68 . The load-sensing transducers  69 ,  70  generate as a function of the respective support load F 2 , F 3  input signals X 2 , X 3  which in an electronic calculating unit  71  generate, as a function of a load distribution ratio which is predefined and if necessary variable as desired, an output signal X 1  which via a switching valve  72  of any design leads to pressurization or relief of pressure of the lifting cylinder  33  of the at least one support wheel  15 . In this way it is possible to adjust the support load F 1  of the at least one support wheel  15  as a function of the support loads F 2 , F 3  of the axles  14 ,  67  of the agricultural harvesting machine  1 . Further, associated with the at least one support wheel  15  can be a load-sensing transducer  74  which generates an input signal X 4  which is dependent upon the support load F 3  and which in the electronic calculating unit  71  can be used as a measure of the pressure p acting on the ground  37  by the agricultural implement  13 . In this way it is possible to adjust the support load distribution as a function of support of the agricultural implement  13  on the ground  37  as well. 
     Because agricultural harvesting machines designed as combine harvesters  2  have a crop storage device  73 , the mass of the agricultural harvesting machine  1  and hence the support loads F 2 , F 3  applied to the axles  14 ,  67  varies constantly. To achieve continuous adaptation of the support load F 1  of the support wheel  15  in spite of support loads F 2 , F 3  varying during the harvesting process, the switching valve  72  can be designed as a proportional valve  72  known in the art whose control signal X 1  leads to permanent adaptation of the support load F 1  to the varying mass of the agricultural harvesting machine  1 . 
     In order that, during lifting and lowering of the support wheel  15 , the effect of this change of position on the support load F 1  of this support wheel  15  remains small, the lifting cylinder  33  which allows the change of position is arranged in an essentially vertical direction on the receiving device  5 . If adaptation of the support load F 1  of the support wheel  15  to the other support loads F 2 , F 3  is not effected, it is contemplated that the lifting cylinder  33  of the support wheel  15  can also be blocked in a manner known in the art and therefore not described. 
     To ensure, even when there is no agricultural implement  13 , that the support wheels  15  according to the invention support a minimum load on the ground  37 , on the one hand the lifting cylinders  9  which pivot the receiving device  5  can be designed as double-acting lifting cylinders  9 , so that by means of the piston rod  8  retracting into the cylinder  11  of the lifting cylinders  9  it can be fixed how high the load to be supported on the ground  37  by the support wheels  15  is to be. If the lifting cylinders  9  which pivot the receiving device  5  are single-acting, between the receiving device  5  and the agricultural harvesting machine  1  can be interposed a traction cylinder  75  which under pressurization forces the support wheels  15  according to the invention onto the ground  37 , wherein by pressurization of the traction cylinder  75  the quantity of the load F 1  to be supported can be determined. 
     Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims and their equivalents.