Abstract:
A running device for a trailer type machine and in particular a pick-up, arranged at each end thereof. The device includes at least a front wheel ( 43 ) and a rear wheel ( 37 ) whereof the axles are made integral with at least a frame member ( 31, 33 ) linked to the machine body ( 5 ) which is mounted rotating relative to the body ( 5 ) thereof about an axis (xx′,  23 ) parallel to that of the wheels ( 37, 43 ).

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a running device for farm machine and in particular for machines intended for collecting swaths on the ground of the pick-up type which are pushed by a self-propelled machine, such as a silo filler. 
     It is known that cultivated ground on which machines of this type have to move usually presents particularly uneven surfaces of which the hollows and bumps impart to the pick-up, during its displacement, repetitive shocks which have a detrimental effect on the integrity thereof. 
     In the prior state of the art, farm machines have been proposed, equipped at each of their ends with running means constituted by a front wheel and a rear wheel whose axles are connected by a rectilinear frame member articulated at its centre on the machine body, which has the effect of ensuring a “smoothing” of the curve of the land travelled over. 
     SUMMARY OF THE INVENTION 
     The present invention has for its object to improve the devices of this type by proposing a device which makes it possible to arrange on this type of machine wheels whose diameter is greater than that usable in the prior state of the art, which has the effect of increasing the contact surface thereof with the ground. 
     The present invention thus has for its object a running device for trailer-type machine, particularly a pick-up, arranged at each end thereof, comprising at least one front wheel and one rear wheel of which the axles are made integral with at least one frame member which is mounted for rotation relative to the body of the machine, about an axis parallel to that of the wheels, characterized in that this frame member is in the form of a V so that the axis of rotation of this frame member on the machine body is located below the axis of rotation of each of the wheels. Said axis of rotation of the frame member is preferably located at the level of the intersection of the two branches of the V. 
     The device may comprise two wheels which may for example be located in the same plane. However, it is equally possible that at least one of the wheels of one of the ends, front or rear, is not disposed in the same plane as one of the wheels of the other end. 
     In one form of embodiment of the invention, at least one front wheel lies outside the machine and at least one of the rear wheels lies inside, therebeneath. 
     In another form of embodiment of the invention, the device comprises means for adjusting the difference in height separating the axis of rotation of the frame member and the axis of rotation of a wheel. The adjusting means may be such that the frame member comprises an outer longitudinal element extending fowardly and an inner longitudinal element extending rearwardly, at least one of these longitudinal elements being provided, at its free end, with means for fixing an adjusting plate on which a hub supporting a wheel is mounted. 
     One of the advantages of the pick-up according to the invention is that it makes it possible to increase the contact surface of the wheels with the ground. Such an increase is due firstly to the addition of at least one second wheel. But, in addition, the present invention allows a running device to be produced in which the point of application of the effort which is transmitted to the wheels is nearer the ground that the axis of rotation of these wheels. Apart from the fact that the stability is thus improved, this results in it then being possible to mount on the machine wheels whose diameter is larger than that usable in the prior state of the art, which has the effect of increasing the contact surface of said wheels with the ground and of improving the adherence of the machine. 
     Furthermore, when, as shown in FIG. 1, one of the front wheels of a pick-up equipped with a running device according to the invention, encounters a small obstacle of height h, the point of application A of the efforts between the wheels and the machine body moves, for its part, by a height which is in the ratio of the corresponding lever arms, i.e. those constituted, on the one hand, by the distance of the axle of the wheel in question with the point of application A and, on the other hand, the distance of this same axle with that of the other wheel. Thus, if the supporting point lies at an equal distance between the two wheels, such a displacement will thus be equal to h/2, that is, half the height h of the obstacle. 
     The present invention also makes it possible to improve ground adherence of the pick-up by enabling the front and rear wheels thereof to be easily offset in the two different vertical planes. Under these conditions, it will be understood that, as the rear wheel has a different runway from that of the front wheel, it will come into contact with virgin ground since the latter will not have suffered the passage of the front wheel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A form of embodiment of the present invention will be described hereinafter by way of non-limiting example, with reference to the accompanying drawings, in which: 
     FIG. 1 schematically illustrates one of the advantages of the invention. 
     FIG. 2 is a side view of a swath collecting device equipped with the running device according to the invention and with a partially shown driving silo filler. 
     FIG. 3 is a partial schematic plan view in section of a variant embodiment of the running device according to the invention shown in FIG.  2 . 
     FIG. 4 is a partial vertical sectional view of the device shown in FIG. 3 along line IV—IV thereof. 
     FIG. 5 is a partial schematic plan view in section of a variant embodiment of the running device according to the invention. 
     FIG. 6 is a plan view of another variant embodiment of the running device according to the invention. 
     FIGS. 7 and 8 are schematic side views of a pick-up placed in raised position by a driving silo filler, shown partially, respectively before and after tipping of the running device according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 2 to  4  show a swath collecting device  1 , or pick-up, of which the displacement is ensured by a silo filler  3  shown partially in the drawing. The pick-up  1  is constituted by a machine body  5  which is fixed to the silo filler  3  via an oscillating frame  7  which constitutes a fixation device known by the prior state of the art. This oscillating frame  7  is fixed to the silo filler by two anchoring points  9  and  11  by means of two respective holding couplings (shown schematically in the Figures) namely an upper coupling  13  being fixed to the anchoring point  9  and a lower coupling  15  which is fixed to the lower anchoring point  11 . The means for fixation of the pick-up on the silo filler make it possible, in position of non-use, to pivot the pick-up about a pivot axis  19  of the silo filler, as shown in FIGS. 7 and 8. 
     Each of the transverse ends of the pick-up  1  is provided with a running device  21  which is intended to ensure the displacement of the pick-up  1  over the ground during work, when the latter is pushed by the silo filler  3 . 
     The running device  21  according to the invention comprises a wheel supporting frame member mounted to rotate on the machine body  5  about a horizontal and transverse axis xx′, this support being essentially constituted by a transverse shaft  22  made fast, at each of its ends, with at least one tubular longitudinal element of rectangular section, namely an anterior longitudinal element  31  which extends towards the outside of the pick-up and a posterior longitudinal element  33  which extends therebeneath. 
     The shaft  22  is rotatably mounted inside a tubular element  23  fast with the machine body  5 . The posterior longitudinal element  33  is provided, at its free end, with a hub  35  supporting a rear wheel  37  of axis zz′ and the anterior longitudinal element  31  is provided, at its free end, with means for fixing an adjusting plate  39  on which is mounted a hub  41  supporting a front wheel  43  of axis zz′. The adjusting plate  39  is fixed on the anterior longitudinal element  31  by bolting and comprises an assembly of holes  40  for fixing this plate  39  on the longitudinal element  31 , at different positions more or less distant from the base of the pick-up, so as to adjust the wheel  43  in height and consequently adjust the ground clearance of the front part of the pick-up. The ground clearance of the wheel  43  might also be adjusted by any other means. For example, the end of the shaft  22  may be provided with flutings and the end of the longitudinal element  31  opposite the wheel  43  with a recess of complementary shape allowing it to be given a plurality of possible angular positions with respect to the shaft  22 . 
     According to the invention, as is more particularly visible in FIGS. 2 and 4, the anterior ( 31 ) and posterior ( 33 ) longitudinal elements of the running device present, seen in the horizontal and transverse direction, a shape in V-form or more precisely an upwardly open obtuse angle. In this way, the axis of rotation xx′ of the wheel supporting frame member which is located at the apex of the V or of the obtuse angle, is positioned beneath the axis of rotation of each of the anterior and posterior wheels at a distance f from the axis zz′ thereof, which makes it possible to use wheels of larger diameter than would be possible to do if the longitudinal elements  31  and  33  were rectilinear. 
     The machine body part  5   a  located above the rear wheel  37  comprises a flange  42  for fixation, in the same way as the upper posterior part of the longitudinal element  33  which presents a flange  44 . Between these two flanges  42  and  44  there has been disposed an adjustable connecting rod  47  constituted by a tubular body  48  of which one end is fixed on the lower flange  44  inside which is slidably mounted a piston  49  of which the free end is articulated on the flange  42 . Connection of the body  48  and of the piston  49  is effected by a transverse pin  45  which passes through the connecting rod body  48  and one of a series of transverse holes made over the length of the piston  49 , which makes it possible to connect the longitudinal element  33  of the machine body  5  in position of transport of the pick-up. 
     When the pick-up is in work position, it is held by the silo filler  3  by means of the upper ( 13 ) and lower ( 15 ) couplings, and its machine body  5  may pivot in the plane constituted by the intermediate holding frame  7 , and the running device constituted at each of its transverse ends by one or two longitudinal elements and the wheels which are fixed thereto, may pivot about the axis of rotation constituted by the tubular element  23 , which enables it to adapt itself easily to the different relief of the ground that it encounters during its displacement. 
     Furthermore, as shown in FIG. 1 when one of the front wheels  43  encounters an obstacle  6  of height h, the running device pivots about an axis constituted by that of its rear wheel  37 , so that the tubular articulation element  23 , connected to the machine body  5  of this pick-up, undergoes for its part a vertical displacement substantially equal to half the height h when the longitudinal elements  33  and  31  have substantially identical lengths e. It will be understood that such a device makes it possible very substantially to minimize the stresses to which the machine is thus subjected. 
     Furthermore, and as mentioned hereinbefore, the device according to the present embodiment makes it possible to improve the contact of the rear wheels  37  with the ground, insofar as said wheels are made to run over virgin contact surfaces, i.e. surfaces over which the front wheel  43  did not itself move. 
     As shown in FIGS. 7 and 8, it is observed that, when the work of the pick-up is finished, the lower ( 15 ) and upper ( 13 ) couplings of the silo filler are displaced into upper position, causing the pick-up to make a rotation centred on the axis of rotation  19  of the silo filler  3 . Consequently, the pick-up tends to occupy a position of the type such as shown in FIG. 7, in which its front wheels  43  are located at a level higher than those of the rear wheels  37 , which implies that the ground clearance of the latter is relatively reduced. 
     The running device according to the invention, insofar as it may pivot about the transverse tubular element  23 , makes it possible to increase the ground clearance of the pick-up in raised position. In effect, it will be arranged for the weight of the front wheel  43  of the anterior longitudinal element  31  and of the plate  39  to be greater than the weight of the posterior longitudinal element  33  and of the wheel  37 , so that, once the pick-up is raised, as shown in FIG. 7, the running device pivots about the transverse element  23  thus causing the front wheel to descend and the rear wheel  37  to rise, in order to take a position such as the one shown in FIG.  8 . It is observed that, under these conditions, for an identical lifting procured by the silo filler, the ground clearance of the pick-up is very clearly improved. 
     When it is desired to improve the contact of the running device with the ground, it is possible, as shown in FIG. 5, to extend the longitudinal element  31  towards the rear so that the free end thereof receives a hub  35 ′ provided with a wheel  37 ′. It will preferably be arranged that the two rear wheels  37  and  37 ′ be symmetrical with respect to the longitudinal axis uu′ passing through the centre of the tubular element  23 . 
     When, in applications where the wheels of the machine do not present any problem as to their adherence with the ground over which the latter is moving, the running device according to the invention may present only two wheels, namely a front wheel  43  and a rear wheel  37 ′, these two wheels being disposed on the same longitudinal element  31  so that they thus lie in the same plane.