fig1 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 fig2 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 . fig3 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 fig3 ) can also be double - acting as shown in fig4 . 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 fig3 can be associated with the pipe systems 38 or 45 , 49 , to avoid sudden loading . the support wheels 15 shown in fig2 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 fig1 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 .
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 .