Patent Publication Number: US-9883668-B2

Title: Self propelled agricultural application machine

Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 120 as a continuation of U.S. patent application Ser. No. 13/059,175 filed Feb. 15, 2011, now U.S. Pat. No. 9,526,202, the full disclosure of which, in its entirety, is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of Invention 
     The invention relates to self-propelled agricultural application machines, such as crop sprayers, which comprise a chassis which carries a storage tank for the material to be applied. 
     Description of Related Art 
     Agricultural application machines such as crop sprayers comprise a large volume tank carried on a chassis. Such machines can be trailed behind a tractor or provided as a self-propelled unit having an integral cab and engine. The machine further comprises an extending boom which provides a transverse line of uniformly spaced spray nozzles connected by pipes to the tank. During operation the application machine is moved across fields of crops such as cereals and maize to apply liquid fertilizer or chemical treatment such as herbicides, fungicides and pesticides to the crop in a controlled manner. 
     The application machines are typically driven across the fields utilizing “tram-lines” which are often used several times throughout the growing cycle to make different applications, thereby minimizing the area of lost crop through flattening by the wheels. The minimum turning radius affects the length of the tram-lines especially at the turning points on the headlands. In turn, this affects the area of crop which is lost to providing the tram-lines. 
     In addition, the minimum turning radius dictates the limits of the machine to reach corners and edges of fields having complex shapes. Also, the turning radius limits the maneuverability of the machine. 
     BRIEF SUMMARY OF THE INVENTION 
     It is thus an object of the invention to provide a self-propelled agricultural application machine with a reduced minimum turning radius. 
     It is another object of the invention to provide a self-propelled agricultural application machine which has a reduced assembly time. 
     According to the invention there is provided a self-propelled agricultural application machine comprising a chassis which carries a storage tank for the material to be applied, the chassis comprising a single central longitudinal beam from which at least a pair of wheels are suspended. By forming the chassis from a single beam in this way, the steering angle of steerable wheels can be increased whilst still keeping the track width within constraints set by maximum widths permitted on highways. 
     In some countries, such as The United Kingdom, rural highways are typically narrow and limit the width of self-propelled application machines. The resulting separation between the steerable wheels and a conventional chassis is often inadequate to permit a satisfactory steering angle. To compound the problem of large turning radii, application machines often employ wheels of large diameter to achieve sufficient ground clearance. By providing a central longitudinal beam to provide a ‘backbone’ for the machine in accordance with the invention, the separation between the wheels and the chassis can be increased, in turn increasing the maximum steering angle without sacrificing wheel diameter. 
     In a preferred arrangement the application machine comprises two pairs of wheels which are suspended from the longitudinal beam. At least one of the two pairs of wheels are steerable. Preferably, both pairs of wheels are steerable delivering even smaller turning radii. As mentioned above, the provision of a central longitudinal beam allows increased turning angles. In one preferred embodiment, the steerable wheels have a maximum steering angle which is greater than 35 degrees, for example 37 degrees. 
     The wheels are preferably independently suspended from the longitudinal beam. 
     Preferably, the application machine further comprises a cab which is supported forwardly of the longitudinal beam by a cab support structure which is itself supported by the longitudinal beam. Advantageously, this places the cab in front of the chassis rather than on top. In turn this improves the forward visibility for the driver. Furthermore, the cab is disposed lower which lowers the vehicle&#39;s centre of mass thus increasing the stability thereof. 
     Preferably, the application machine further comprises a boom assembly which is suspended from the rear section of the longitudinal beam. Advantageously, this permits a single, centrally-disposed, parallelogram suspension structure to be employed instead of the conventional double structure. This reduces the number of components required thus saving cost. 
     The boom assembly is preferably pivotally mounted to the longitudinal beam to allow the boom assembly to be raised and lowered. A boom lift actuator may be provided and connected between the longitudinal beam and the boom assembly to lift and lower the boom assembly. 
     In a preferred embodiment the application machine further comprises an engine which is disposed to one side of the longitudinal beam and between two wheels on one side of the machine. The central longitudinal beam structure permits the engine to be located on a similar level to the chassis rather than above as in conventional self-propelled application machines. This lowers the centre of mass and improves the stability of the vehicle. Furthermore, access to the engine for maintenance is improved because there is no need for the operator to climb on top of the vehicle frame. This is both safer and more convenient. 
     Preferably, the engine comprises an output drive shaft which is transversely orientated. Conveniently, this permits the pumps and/or transmission components connected to the output of the engine to be located on the other side of the longitudinal beam opposite the engine thus distributing the weight more evenly. 
     The application machine may further comprise a fuel tank which is disposed to one side and forwardly of the longitudinal beam. To distribute the overall weight more effectively, the fuel tank is preferably disposed on the opposite side of the longitudinal beam to that of the engine. 
     In one preferred arrangement the fuel tank is disposed under the cab which optimises the available space and maintains a low centre of mass. 
     The storage tank may be asymmetric about a longitudinal vertical plane along the centre of the chassis. By moving away from the conventional symmetrical tank profile, cavities and spaces within the overall machine profile which are present only on one side thereof can be exploited to store application material so as to optimise the available volume whilst increasing the design flexibility to centralise the centre of mass. An asymmetric tank lends itself well to a machine with a relatively heavy component, for example the engine, having a centre of mass which is offset from the plane of asymmetry. In this case, the volume of the storage tank disposed to one side of the plane is preferably greater than the volume of the storage tank disposed to the other side. Advantageously, this allows the mass of a laden tank to counterbalance the weight of the heavy component thus increasing the stability of the machine. 
     In a preferred embodiment, an engine which is disposed on one side of the chassis and a portion of the storage tank is disposed on the other side of the chassis so as to counterbalance the weight of the engine. In a preferred arrangement, said portion is disposed opposite the engine so as to reduce any torsional force in the chassis. 
     Furthermore, by providing said portion of the tank by extending the volume of the tank downwardly into an available cavity, the advantageous counterbalancing effect remains even when the application material load is low. In other words, the last part of the tank to empty is the counterbalancing portion thus improving stability until the end of the application session. 
     This summary is provided to introduce concepts in simplified form that are further described below in the Description of Preferred Embodiments. This summary is not intended to identify key features or essential features of the disclosed or claimed subject matter and is not intended to describe each disclosed embodiment or every implementation of the disclosed or claimed subject matter. Specifically, features disclosed herein with respect to one embodiment may be equally applicable to another. Further, this summary is not intended to be used as an aid in determining the scope of the claimed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages of the invention will become apparent from the following description of specific embodiments with reference to the appended drawings in which— 
         FIG. 1  is a perspective view of a self-propelled agricultural sprayer in accordance with the invention; 
         FIG. 2  is a side view of the sprayer of  FIG. 1 ; 
         FIG. 3  is a perspective view of the chassis of the sprayer of  FIG. 1 ; 
         FIG. 4  is an underside view of the sprayer of  FIG. 1  (with engine removed); 
         FIG. 5  is another underside view of the sprayer of  FIG. 1 ; 
         FIG. 6  is a plan view of the part of the sprayer shown in  FIG. 3 ; 
         FIG. 7  is a perspective view of the tank of the sprayer of  FIG. 1 ; 
         FIG. 8  is a plan view of the tank of  FIG. 7 ; and, 
         FIG. 9  is a rear view of the tank of  FIG. 7 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the views of the drawings. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1 to 6 , a self-propelled arable crop sprayer  10  comprises a pair of front wheels  12  and pair of rear wheels  14  each wheel being separately mounted to a chassis  100  by respective variable height suspension means. The sprayer  10  further comprises a tank  15 , a boom assembly  16  and driver&#39;s cab  17 . The tank  15  accounts for the majority of the sprayer&#39;s volume and serves to hold the liquid material which is to be applied to a field. By way of example, the liquid material may comprise fertilizer or other chemical treatment such as herbicides, fungicides, pesticides or growth restrictors. 
     The liquid material is delivered in a controlled manner to spray nozzles (not shown) located on the boom assembly  16  by a network of supply pipes (not shown). In the transport mode (shown in  FIGS. 1 and 2 ) the boom assembly  16  is retracted so as to remain substantially within the profile of the vehicle body thus allowing safe movement on the highway. In an operating mode the boom assembly  16  is extended so as to provide a transversely extending boom, having a width of 24 meters for example. Driven across an arable field, the liquid material is sprayed onto the crop in strips 24 meters wide at a time. The driver located in cab  17  controls the steering of the sprayer and the control of the liquid material application. It should be understood that  FIGS. 1 and 2  show only one half (right-hand side) of the folded boom assembly  16 . 
     With reference to  FIGS. 3 to 6 , the chassis  100  comprises a single, centrally-disposed, longitudinal beam  110  to which the respective wheel and boom suspension means are mounted. A first section  110   a  of the longitudinal beam  110  extends from the rear of the sprayer  10  to approximately a region between the front wheels  12 . A second section  110   b  is connected to the first section  110   a  and extends forwardly at a lower height to the front of the sprayer  10 . 
     All four wheels  12 ,  14  are steerable. Each of the four wheels  12 ,  14  is suspended from the longitudinal beam  110  by a respective wheel suspension assembly  115  which may, or may not, allow for adjustments to the suspension height of the chassis  100  and/or adjustments to the track width, that is the distance between opposite wheels. Each wheel suspension assembly is secured to the longitudinal beam  110  by appropriate means, for example by brackets bolted to the underside thereof. 
     By forming the chassis  100  from a single beam  110  in this way, the steering angle of the steerable wheels  12 ,  14  can be increased whilst still keeping the track width within constraints set by maximum widths permitted on highways. As can be seen from  FIG. 4 , the maximum achievable steering angle .theta. can exceed 30 degrees thus making the chassis arrangement particularly attractive to farmers and contractors desiring small turning radii from their application machines. 
     A further advantage of the chassis architecture is that it allows the engine  111  to be mounted to one side of the chassis  100  (see  FIG. 5 ) thus lowering the overall centre of mass. Further, the lower positioning of the engine  111  improves access for the operator thus making maintenance far easier and safer. The engine  111  is conveniently located in the space provided between the two wheels  12 ,  14  on the right-hand side of the sprayer  10 . An output drive shaft  112  which is driven by the engine  111  is transversely orientated with respect to the direction of travel of the sprayer  10 . The drive shaft  112  is connected through the longitudinal beam  110  to hydraulic pumps  113  associated with the sprayer propulsion and spraying gear located on the left-hand side of the sprayer  10 . 
     The second section  110   b  of the longitudinal beam  110  provides part of a cab support structure referenced generally at  117  in  FIG. 3 . The longitudinal part  110   b  has connected thereto a plurality of transverse components  118  to adequately support the weight of cab  17 . By providing the cab support structure  117  at a lower height to that of the first section  110   a  of the longitudinal beam, and thus the tank  15  supported thereon, the centre of mass and the overall height of the sprayer is lowered. Furthermore, the driver&#39;s visibility of the crop is improved. 
     A lower platform  120  is attached to the second section  110   b  so as to be positioned to the left-hand side of the cab  17 . A raised platform  122  is attached to the first section  110   a  by a platform support structure  123  so as to be positioned behind the cab  17 . A set of steps  124  is provided between the lower platform  120  and the raised platform  122  to allow a driver to reach the latter. From the raised platform  122 , a driver is able to access the top of the tank  15 . 
     Turning to the rear of the chassis  100 , a boom support structure  130  is secured to the rear of the longitudinal beam  110 . The boom assembly  16  is pivotally mounted to the boom support structure  130  to allow the boom assembly  16  to be raised and lowered. A boom lift actuator (not shown) is connected between the boom support structure  130  and the boom assembly  16  to lift and lower the boom assembly. 
     With reference to  FIGS. 7, 8 and 9 , the storage tank  15  is formed of moulded plastic and has a volume of 4500 liters for example. As can be seen from  FIG. 9 , the tank  15  comprises a downwardly-extending portion  150  on the left-hand side which is not reflected about longitudinal and vertical plane X. In other words there is not an equivalent volume extension on the right-hand side. Therefore, in accordance with the invention, the tank is asymmetric about the longitudinal vertical plane X at least across the horizontal section Y ( FIG. 6 ). 
     Furthermore, as can be seen from  FIG. 8 , the tank comprises a forwardly-extending portion  155  on the left-hand side which is also not reflected about plane X. This forward portion  55  comprises a capped filler hole  156  for filling the tank  15  with application material, typically via a hose (not shown). 
     The two volume extensions  154 ,  155  deliver a significantly greater tank volume on the left-hand side than on the right-hand side. The weight of the engine  111  is thus counterbalanced by the asymmetry thereby improving the overall stability of the sprayer  10 . 
     The downwardly-extending portion  154  is disposed opposite the engine  111  thus minimizing any torsion forces on the relatively narrow chassis  100 . Moreover, being the lowest part of the tank  15 , the portion  154  is the last part of the tank to empty during an application to a field. Therefore, even when the level of application material present in the tank  15  is low, the weight of the side-disposed engine  111  is counterbalanced. 
     The sprayer  10  further comprises a fuel tank also disposed on the right-hand side of the chassis  100 . The downwardly-extending portion  154  serves also to counterbalance the weight of the fuel tank and the fuel contained therein across the longitudinal plane X. 
     The tank  15  also comprises an extraction pipe  58  located at the bottom of the downward extension  54  to extract the application material during operation. 
     In summary, there is provided a self-propelled agricultural application machine comprising a chassis which carries a storage tank for the material to be applied is provided. The chassis comprises a central longitudinal beam from which at least a pair of wheels is suspended. The narrow chassis allows steerable wheels to be positioned at tolerable track widths whilst permitting a large steering angle and thus small turning radii. 
     From reading the present disclosure, other modification will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the field of agricultural application machines and component parts therefore and which may be used instead of or in addition to features already described herein.