AU2008200716B2 - Suspension system - Google Patents

Abstract

A suspension system for dampening movement between a first body and a second body. The suspension system includes a first dampener connected at a 5 first location between the first body and second body; and a second dampener connected at a second location between the first body and second body. The first dampener is operatively connected to the second dampener such that actuation of the first or the second dampener in one direction causes the other of the first or the second dampener to have an increased dampening effect in 10 the opposite direction. The invention is particularly applicable when used as a yaw suspension system for an articulated boom arm. X:\ECP\Patent Speofications\ovisionalsyaw suspension system\Yaw Suspension System - complete.final doc 40 22 36 10 26 2 3 34 2 325 14 282 30 20

Description

1 P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: SUSPENSION SYSTEM Applicant: Goldacres Holdings Pty. Ltd. The following statement is a full description of this invention, including the best method of performing it known to me: T:\DDPACAP\2007900824-CAP FORMS(14 2.08) doc 2 SUSPENSION SYSTEM Field of the Invention 5 The present invention generally relates to a suspension system. The invention is particularly applicable when used as a yaw suspension system for an articulated boom arm and it will be convenient to hereinafter disclose the invention in relation to that exemplary application. However, it is to be appreciated that the invention is not limited to that application and could be 10 used as a suspension system where it is required to balance suspension forces between two or more suspension points. Background of the Invention 15 The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application. 20 A number of broadacre sprayers are currently used for spraying liquids over an expanse of ground. Most systems include a vehicle, such a trailer structure or self propelled vehicle, which includes a distribution tank for distributing liquid from a supply tank through the sprayer and a spray boom 25 having a pair of pivotably mounted boom arms through which the liquid is sprayed on the ground or crops over which the sprayer travels. During spraying operation, each boom arms projects laterally from each side of the frame to allow a series of spray nozzles spaced along the length of each boom arm to deliver liquid over the wide span that each of the boom arms extend across the 30 ground. As can be appreciated, when the broadacre sprayer is in use, the boom arms transfers a number of different forces to the vehicle through a connection between the vehicle and each boom arm. The spray boom is therefore typically X ECP\Pateru Spediabomx visianls~ya w sSpe iof sysfemNY2.a S~,pen5ion SyStem - mplete finaidoc 3 connected to the vehicle through a boom suspension arrangement which dampens the transfer of these forces from the spray boom to the vehicle. Such suspension arrangements typically include a number of suspension systems for dampening the transfer of forces in different directions. It is common for such a 5 suspension arrangement to include separate suspension systems to dampen pitch forces applied about a lateral axis, roll or twisting forces applied along the boom arms and yaw forces applied about a vertical axis. Most existing boom suspension systems include a basic stiff spring and 10 shock absorber combination. While such a combination provides adequate shock absorbing functions, a manufacturer of such spray vehicles must use a different size spring and shock absorber combination to meet the force requirements for each different sized boom and vehicle combination. Moreover, each spring and shock absorber combination tend to act independently when 15 the boom experiences a load force thereby providing separate dampening functions to each section that the spring and shock absorber combination are attached. It would therefore be desirable to provide an alternative suspension 20 system which is, in an exemplary application, suited for use as part of a suspension arrangement between a boom arm and a vehicle. Summary of the Invention According to the present invention, there is provided a yaw suspension 25 system for dampening movement between a which includes at least one boom arm and a second body comprising a vehicle section, the suspension system including: a first dampener connected at a first location between the first body and second body; and 30 a second dampener connected at a second location between the first body and second body, wherein the first dampener is operatively connected to the second dampener such that actuation of the first or the second dampener in one Yaw Suspension System - completefinal 4 direction causes the other of the first or the second dampener to have an increased dampening effect in the opposite direction. The operative connection between each of the dampeners ensures that 5 the at least two different dampeners of the suspension system according to the present invention interact, rather than acting independently as is the case with existing spring-shock absorber systems. This allows the suspension system of the present invention to provide a responsive dampening system, where forces acting on one dampener also produce a dampening response in the other 10 dampener. This interaction increases the dampening function of the overall suspension system on the relative movement of the first body with respect to the second body. The first and second dampener can be located in any suitable location 15 relative to one another between the first body and second body. It is preferable however, for each of the first and second dampeners to be laterally spaced apart along a span of overlap between the first body and second body. The dampeners therefore are able to provide a dampening function to two different and spaced apart locations between the first body and second body. Of course, 20 it is preferable for the dampeners to be positioned about a point or axis of movement between the first body and second body. Therefore in some embodiments, the first dampener and second dampener are spaced apart about an operative pivot axis about which the first body and second body can move relative to one another. In one preferred embodiment, the pivot axis is a vertical 25 pivot axis and the suspension system is used as a yaw suspension system which dampens yaw forces applied to the first and/or second body about this pivot axis. Each dampener typically includes moving parts including a biasing or 30 resilient means which provide the dampening force for the suspension system. In most cases, the moving parts of the dampener are movable along a single axis, thereby providing a dampening force in the direction of that axis. When two separate and spaced apart dampeners are used, it is preferable for the moving parts of these dampeners to move along a substantially parallel axis so X:\ECP\Patent Specifications\Provisionals ya suspension system\Y.aw Suspension System - omplete.final doc 5 as to provide complementary dampening action to any relative movement of the first body to the second body. More preferably, the first dampener is movable about a first axis and the second dampener is movable about a second axis, the first axis being substantially parallel with the second axis. 5 The operative connection between the first dampener and second dampener can take many forms. In some cases it can be an electronic connection which includes a controller which functions to actuate the first or second dampener when the other of the first or second dampener is actuated. 10 In other embodiments, the operative connection can be a physical system in which a physical connection is made. In such physical systems it can be advantageous for the suspension system to further include at least one buffer operatively connected to one or both of the first dampener or second dampener. The buffer typically functions in the operative connection between the two 15 dampeners. In those embodiments were the first dampener and second dampener are operatively connected using an operative medium, the at least one buffer can in some forms comprise an accumulator which accumulates said operative medium. In this sense, the accumulator functions as a reservoir of operative medium (fluid or the like) between each dampener which receives 20 operative medium when one of the dampeners is actuated. As can be appreciated, in those embodiments where the at least one buffer includes an operative medium, the dampening action of the suspension system can be affected by the amount and/or pressure of the operative medium 25 in the at least one buffer. It is therefore possible in some embodiments to use the at least one buffer to tune the dampening force of one or both of the first dampener or second dampener. In this respect, the amount of operative medium in the at least one accumulator is used to tune the dampening force of one or both of the first dampener or second dampener. Typically, adding 30 operative medium to the system would increase the dampening force of the suspension system and removing operative medium from the system would increase the dampening force of the suspension system. X:\ECP\atent Speofica ns\Provinals\yaw suspension system\Yaw Suspension System - completeflinal doc 6 The first and second dampener can be any suitable dampener such as servo motors, air actuated pistons or the like. However, in one exemplary embodiment, the first dampener and second dampener are hydraulic pistons. In such a suspension system, the first hydraulic piston is preferably operatively 5 connected to the second hydraulic piston through at least one hydraulic connection which allows hydraulic fluid to be transferred between each hydraulic piston. In a more preferred embodiment, the first hydraulic piston is operatively 10 connected to the second hydraulic piston through two hydraulic connections. In this respect, each hydraulic piston can include a first chamber which is compressed when the hydraulic piston is actuated in a first direction and a second chamber which is compressed when the hydraulic piston is actuated in a second direction. Preferably, the first chamber of the first hydraulic piston is 15 operatively connected to the second chamber of the second hydraulic piston and the second chamber of the first hydraulic piston is operatively connected to the first chamber of the second hydraulic piston. Consequently, actuation of the first or the second hydraulic piston in one direction causes the other of the first or the second hydraulic piston to have an increased dampening effect in the 20 opposite direction. Therefore, if for example, the first hydraulic piston is actuated causing the first chamber of the first hydraulic piston to be compressed, hydraulic fluid will be transferred to the second chamber of the second hydraulic piston via the hydraulic connection. This hydraulic fluid transfer pressurises the second chamber, increasing the dampening force in 25 that chamber in response to the actuation of the first hydraulic piston. Again, it can be advantageous to include at least one accumulator in the suspension system which is operatively connected to one or both of the first hydraulic piston or the second hydraulic piston. More preferably, the 30 suspension system includes a first accumulator operatively connected to the first chamber of the first or second hydraulic piston and a second accumulator operatively connected to the second chamber of the first or second hydraulic piston. In these forms, the accumulator accumulates at least a portion of a X:\ECP\Patent Specificain\Povisionals yw suspension system\Yaw Suspension System - completefinaldoc 7 hydraulic medium used in the first and second hydraulic pistons when the first or second hydraulic piston is actuated. In some instances, for example when a significant modification is made 5 to one of the first or second bodies, it is desirable to be able to tune or modify the suspension system to better suit the modified arrangement. In this respect, the dampening force in the suspension system can in some embodiments be tuned by changing the amount of a hydraulic medium in the at least one accumulator. However, in order to add or remove a hydraulic medium or other 10 operative medium from the system for tuning, it is preferred that the suspension system further includes one or more charge points in which hydraulic medium can be fed or removed from the suspension system. Similarly, it is preferable for the suspension system further includes at least one pressure sensor at or near one or more accumulator for measuring the hydraulic pressure of the 15 suspension system. Furthermore, in some embodiments, the suspension system further includes a hydraulic connection to an external system for use in bleeding and calibrating the suspension system. The first body includes at least one boom arm. As can be appreciated 20 the boom arm would typically be supported or otherwise attached to a mounting section or other part attached to a ground engaging section of a device upon which the boom arm functions. In one embodiment, the boom arm is a spay boom for a broad acre sprayer. The broad acre sprayer typically includes a vehicle of some kind. Accordingly, it is preferable for the first body to include 25 the boom arm and for the second body to include the vehicle. In such an embodiment, the spray boom is usually connected to the vehicle using a connection arrangement that includes a suspension system according to the present invention. More preferably, the suspension system according to the present invention in such an embodiment is a yaw suspension system between 30 the boom arm and a mounting section on the vehicle. It should be understood that such a suspension system can be Yaw Suspension System - complete final 8 factory fitted to such a vehicle or retrofitted, replacing an existing suspension system. According to another aspect of the present invention, there is provided a 5 broadacre sprayer including a boom arrangement which is connected to a vehicle through a connection arrangement, the connection arrangement including a suspension system according to the present invention. Brief Description of the Drawings 10 The present invention will now be described with reference to the figures of the accompanying drawings, which illustrate particular preferred embodiments of the present invention, wherein: 15 Figure 1 is a photograph of a self propelled broadacre spray vehicle having an articulated spray boom, the spray vehicle including a connection arrangement between the vehicle and spray boom which includes a yaw suspension unit according to one preferred embodiment of the present invention. 20 Figure 2 is a photograph of the spray vehicle shown in Figure 1 with the spray boom in a fully extended position. Figure 3 is a photograph of the connection arrangement between the 25 spray boom and the vehicle mounting frame of the boom spray vehicle shown in Figure 1 and 2. Figure 4 is a perspective view of the hydraulic pistons insitu in the vehicle mounting frame shown in Figure 3. 30 Figure 5 is an exploded perspective view of the right hand hydraulic piston shown in Figure 4. X:ECP\Patent Specnicatons\Povisionlsyaw sspension system\Yaw Suspension System - cmpletefnal doc 9 Figure 6 is a perspective view of the left hand hydraulic piston shown in Figure 4. Figure 7 is a schematic representation of the yaw suspension system of 5 the yaw suspension unit of the spray vehicle shown in Figure 1. Detailed Description Referring to Figures 1 and 2, there is shown a self propelled sprayer 10 vehicle 10 having an articulated spray boom 11 that includes a suspension system 12 (not shown in Figures 1 and 2) according to the present invention. The sprayer vehicle 10 is essentially a motor driven vehicle having an engine (not shown) which directly drives the wheels 14 to propel the vehicle 10 15 in a desired direction. A user (not illustrated) controls the vehicle 10 from a control cabin 16 located in the forward half of the vehicle 10. The spray boom 11 include a pair of spray boom arms 18, 20 which are pivotably mounted to a skeletal connection frame 22 (best seen in Figures 2 and 3) at the rear of the vehicle. Each boom arm 18, 20 are pivotably connected to one side of the 20 connection frame 22 so as to mount along opposite longitudinal sides of the vehicle 10. The boom arms 18, 20 consist of a skeletal construction made up of two parallel spaced apart frame members 24 and 26 interconnected by a series of cross brace members 28. Each boom arms 18, 20 can be folded in half as shown in Figure 1. A series of nozzles 30 are spaced along the length of each 25 boom arm 18, 20 for spraying liquid delivered from a distribution tank 32 mounted on the back of the vehicle 10. A delivery tube network 34 interconnects the delivery tank 32 and the nozzles 30 for flow of liquid thereto. The spray boom arms 18, 20 pivot about a mounting pivot 36 between a 30 folded storage position as shown in Figure 1, and an extended operational position as shown in Figure 2. In the operational position (Figure 2), the boom arms 18, 20 extend laterally from each side of the vehicle 20 and connection frame 22 to form a laterally elongate framework through which the spray nozzles 41 extend over a large width of ground. In operation, the spray X:\ECMPatent Speafication\rovisionals~yw pension systefYaw Suspenion System - Wmpletefinal doc 10 apparatus 10 is therefore able to spray a particular liquid over a large area of ground with liquid spray. As the vehicle 10 travels along the ground, the boom arms 18, 20 5 transmit a number of forces along their length and through the connection frame 22 to the vehicle 10. Essentially, these forces can be broken into the various directional components of pitch (arrow A in Figure 2), roll (arrow B in Figure 2) and yaw (arrow C in Figure 2). In order to dampen the transmission of these forces from the boom arms 18, 20 to the vehicle 10, a suspension system 40 is 10 provided between the connection frame 22 (shown in Figure 3) and a rear mounting frame 23 (shown in Figure 4) of the vehicle 10. Figures 3 and 4 show a more detailed view of the connection frame 22 and the rear mounting frame 23. Referring firstly to Figure 3, it can be observed 15 that the connection frame 22 is formed of a generally rectangular skeletal framework having a series of generally lateral cross members and a series of vertical strut members. At each side of the connection frame 22 are positioned upper 36A and lower 36B boom pivots 36 where the boom arms 18, 20 attach to the connection frame 22. The connection frame 22 attaches to a rear 20 mounting frame 23 of the vehicle 10 best shown in Figure 4. The rear mounting frame 23 is formed of a generally rectangular skeletal framework consisting of a number of generally lateral cross members and a series of vertical strut members. The rear mounting frame 23 mounts to the rear of the vehicle 10 on two lifting arms 25 (best shown in Figure 2) through rear pivot connections 41 25 and 43. The connection frame 22 is connected to the mounting frame 23 through a three way suspension system that individually dampens the pitch, roll and yaw forces transmitted from the boom 18, 20 to the vehicle 10. Figure 3 shows the pitch suspension system 44 which includes four 30 angled dampening cylinders 45 mounted between the top bar 46 of the mounting frame 23 and the top bar 47 of the connection frame 22. A pair of dampening cylinders 45 is mounted at equal spacing either side of the vertical center of the connection frame 22 so as to provide a balanced dampening force for each of the boom arms 18, 20. X:\ECP\Patent SpedficationsProvisionals~yaw suspension system\Yaw Suspension System - omplete.fnal doc 11 The roll suspension system of the suspension system 40 is not illustrated. 5 The yaw suspension system 50 of the suspension system 40 is shown in Figures 3 to 7. As shown in Figures 3 and 4, the yaw suspension system 50 comprises two connected hydraulic ram or pistons 52 and 54 laterally mounted between vertical struts 55 of the connection frame 22 and vertical struts 56 of the rear mounting frame 23. In the illustrated embodiment, the cylinder section 10 58 of each of the hydraulic pistons 52 and 54 are mounted through mounting frames 60 and 62 to the vertical struts 56 of the rear mounting frame 23 and the distal end of the actuating arm 59 of the hydraulic pistons 52 and 54 are connected to the vertical struts 55 of the connection frame 22. However, it should be appreciated that this orientation could equally be reversed. The 15 hydraulic pistons 52 and 54 are mounted on opposite sides of the mounting frame 23 and connection frame 22 at equal spacing either side of the vertical center of the connection frame 22 so as to provide a balanced dampening force for each of the boom arms 18, 20. 20 As shown in Figures 5 and 6, the hydraulic pistons 52 and 54 are standard two chamber hydraulic rams having a hydraulic chamber (not illustrated) each side of the movable plug (not illustrated) inside the hydraulic cylinder 58. As can be appreciated, the first or front chamber is compressed when the piston arm 59 extends outwardly from the cylinder 58 and the second 25 or rear chamber is compressed when the hydraulic arm 59 is pressed inwardly into the cylinder 58. Each hydraulic piston 52 and 54 has two hydraulic connections which lead to each of the front and rear hydraulic chambers. Referring firstly to the right hand side (RHS) hydraulic piston 52 shown in Figure 5, it can be observed that this hydraulic piston 52 has a front connection 67 and 30 a rear connection 68. If the arm 59 is forced to extend due to actuation, the hydraulic pressure in the front chamber increases causing hydraulic fluid to egress from this front chamber through the front connection 67. Similarly, the left hand side (LHS) hydraulic piston 54 shown in Figure 6, has a front X ECP\Patent Speafications\Provisionas\yaw suspension system\Yaw Suspenson System - complete finaldoc 12 connection 69 and a rear connection 70 which interact in a similar manner as described for the RHS hydraulic piston 52. It should also be appreciated that increasing the hydraulic pressure in 5 one or both of the front and rear chambers of the RHS hydraulic piston 52 or LHS hydraulic piston 54 will increase the resistance of movement of the arm 59 into that chamber and thereby effectively increase the dampening force provided by the hydraulic piston 52 to movement in that direction. 10 Accumulators 65 and 66 are also attached to the mounting frame 23 through mounting frames 60 and 62. As shown in Figures 5 and 6, the accumulators are 1.0 litre 35 bar hydraulic vessels which are connected in circuit with the hydraulic pistons 52 and 54 to form part of the yaw suspension system 50. Effectively, accumulators 65 and 66 function as buffer components 15 for hydraulic fluid during the functioning of the yaw suspension system 50 (describe in more detail below). The hydraulic connections between the each of the hydraulic pistons 52, 54 and accumulators 65 and 66 are best illustrated in Figure 7. As illustrated, 20 each of the hydraulic pistons 52 and 54 are interconnected through a series of hydraulic pipes 72 and 73. In this respect, hydraulic pipe 72 operatively connects the front connection 67 of the LHS hydraulic piston 54 to the rear connection 70 of the RHS hydraulic piston 52. Similarly, hydraulic pipe 73 operatively connects the rear connection 68 of the LHS hydraulic piston 54 to 25 the front connection 69 of the RHS hydraulic piston 52. In effect this hydraulically connects the front chamber of the LHS hydraulic piston 54 to the rear chamber of the RHS hydraulic piston 52. Similarly, the rear chamber of the LHS hydraulic piston 54 is hydraulically connected to the front chamber of the RHS hydraulic piston 52. 30 Each of the accumulators 65 and 66 are also connected in series with an connection 67, 68 of the LHS hydraulic piston 54. In this respect, accumulator 66 is connected in series through hydraulic pipe 74 to the circuit between the front connection 67 of the LHS hydraulic piston 54 and the rear connection 70 of X:%ECPPateM Specta iinsr ioa sya attspension systemYaw Su.spension System - OopiefimtI We 13 the RHS hydraulic piston 52. Similarly, accumulator 65 is connected in series through hydraulic pipe 75 to the circuit between the rear connection 68 of the LHS hydraulic piston 54 and the front connection 69 of the RHS hydraulic piston 52. Each of hydraulic pipes 74 and 75 include an charging inlet 77 and 78 5 which can be used to charge and remove hydraulic fluid from each of the respective accumulators 65 and 66. Each hydraulic circuit between the accumulators 65, 66 and hydraulic pistons 52 and 54 are connected to an external hydraulic circuit 82 through two 10 valves, in this case ball valves 79 and 80. The external hydraulic circuit 82 is in the illustrated embodiment the hydraulic circuit used to lift and lower the boom arms 18, 20 between an operational position adjacent to the ground and a storage position at the height of the distribution tank 32. The external hydraulic circuit 82 can be used to pressurise the hydraulic circuits of the yaw suspension 15 system 50 to a desired pressure. It should be appreciated that the hydraulic pressure in the hydraulic circuits is set to a fixed pressure which is balanced between the respective hydraulic circuits in the yaw suspension system 50. The selected hydraulic pressure typically corresponds to a required dampening characteristic required for the load and size of the boom arms 18, 20. For one 20 embodiment, the hydraulic circuits of the illustrated yaw suspension circuit are pressurised to approximately 2000 PSI. It should also be appreciated that if a user wishes to adjust the dampening force of the suspension system 50, all that need be done is to adjust the pressure of the hydraulic circuits using the external hydraulic circuit 82 or the charging inlet 77 and 78. The dampening 25 characteristics of the yaw suspension system 50 can therefore be tuned to provide a desired dampening response. This can be particularly advantageous if any significant modification is made to the boom arms 18, 20 or the like, where the suspension system 50 can be tuned to better suit the modified arrangement. 30 The yaw suspension system 50 functions as follows: actuation of, for example, the LHS hydraulic piston 54 from lateral movement of the LHS boom arm 18 compresses the hydraulic fluid in the front chamber of the LHS hydraulic piston 54 increasing the hydraulic fluid pressure in this front chamber. The X :ECP\Patent SpeaficationsProvisionaiskya;w suspensionn system\Yaw Suspension System - complete final doc 14 increase pressure causes some fluid to egress from the connection 67 into the connecting pipes 72 and 74. This fluid moves to the connected accumulator 66 and rear chamber of the RHS hydraulic piston 52. This hydraulic fluid transfer pressurises the both the actuator 66 and the rear chamber of the RHS hydraulic 5 piston 52, increasing the hydraulic pressure in both. The increased hydraulic pressure in the chamber increases the dampening force provide by the rear chamber to movement of the piston arm 59. In some extreme cases, the increased pressure may even move the arm 59. This simultaneous response in the opposite hydraulic piston 52 helps dampen the transfer of force from the 10 boom and therefore results in a more responsive dampening system. Similarly, actuation of, for example, the RHS hydraulic piston 52 from lateral movement of the RHS boom arm 20 compresses the hydraulic fluid in the front chamber of the RHS hydraulic piston 52 increasing the hydraulic fluid 15 pressure in this front chamber. The increase pressure causes some fluid to egress from the connection 69 into the connecting pipes 73 and 75. This fluid moves to the connected accumulator 65 and rear chamber of the LHS hydraulic piston 54 pressurising both the actuator 65 and the rear chamber of the LHS hydraulic piston 54. The resulting greater hydraulic pressure in that chamber 20 increases the dampening force in that chamber. As can be appreciated, the accumulators 65, 66 have a buffering effect for the transfer of hydraulic fluid when one or both of the hydraulic pistons 52, 54 are actuated. In this respect, when a hydraulic piston 52, 54 is actuated, at 25 least a portion of a hydraulic fluid pushed out from a chamber of the respective a hydraulic piston is pushed into the accumulator 65, 66. Without the presence of the accumulators 65, 66 in the hydraulic circuits, the percentage of transfer of hydraulic fluid between the front and rear chambers of the respective hydraulic piston 52, 54 would be greater, having a much greater effect on the pressure 30 and responsive dampening force of the suspension system. The accumulators 65, 66 therefore lessen this effect and therefore allow for a more measured response in the opposite hydraulic piston 52, 54 to actuation of the first hydraulic piston 52, 54. X:%ECPPateret Speafic tinsProvisionalskyaw suspension systerflYae Suspension Systemi - a,.nhjete finai dc 15 Of course, the accumulators 65, 66 can also be used to charge the relevant hydraulic circuits to the required hydraulic pressure. It is intended that the illustrated yaw suspension system 50 could be 5 installed between the mounting frame 23 and connector frame 22 during construction of the spray vehicle 10 or could be retrofitted to existing spray vehicles 10 replacing the existing yaw suspension system. It should also be appreciated that the described yaw suspension system 10 50 could be used in a number of other suspension applications between two relatively moving bodies or surfaces, and therefore should not be restricted to the describe application. Those skilled in the art will appreciate that the invention described herein 15 is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention. Throughout the description and claims of the specification the word 20 "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps. X:ECP\Patent SpedfcationsTProvisionals\yaw suspension systemwaw Suspension System - complete final doc

Claims (20)

1. A yaw suspension system for dampening movement between a first body which includes at least one boom arm and a second body comprising a vehicle 5 section, the suspension system including: a first dampener connected at a first location between the first body and second body; and a second dampener connected at a second location between the first body and second body, 10 wherein the first dampener is operatively connected to the second dampener such that actuation of the first or the second dampener in one direction causes the other of the first or the second dampener to have an increased dampening effect in the opposite direction. 15

2. A suspension system according to claim 1, wherein the first dampener and second dampener are spaced apart about an operative pivot axis about which the first body and second body can move relative to one another.

3. A suspension system according to any preceding claim, wherein the first 20 dampener is movable about a first axis and the second dampener is movable about a second axis, the first axis being substantially parallel with the second axis.

4. A suspension system according to any preceding claim, further including 25 at least one buffer operatively connected to one or both of the first dampener or second dampener.

5. A suspension system according to claim 4, wherein the first dampener and second dampener are operatively connected using an operative medium, 30 and wherein the at least one buffer comprises an accumulator which accumulates said operative medium. Yaw Suspension System - compleefina 17

6. A suspension system according to claim 5, wherein the amount of operative medium in the at least one accumulator is used to tune the dampening force of one or both of the first dampener or second dampener. 5

7. A suspension system according to any preceding claim, wherein the first dampener and second dampener are hydraulic pistons.

8. A suspension system according to claim 7, wherein the first hydraulic piston is operatively connected to the second hydraulic piston through at least 10 one hydraulic connection which allows hydraulic fluid to be transferred between each hydraulic piston.

9. A suspension system according to claim 8, wherein the first hydraulic piston is operatively connected to the second hydraulic piston through two 15 hydraulic connections.

10. A suspension system according to any one of claims 7 to 9, wherein each hydraulic piston includes a first chamber which is compressed when the hydraulic piston is actuated in a first direction and a second chamber which is 20 compressed when the hydraulic piston is actuated in a second direction, and wherein the first chamber of the first hydraulic piston is operatively connected to the second chamber of the second hydraulic piston and the second chamber of the first hydraulic piston is operatively connected to the first chamber of the second hydraulic piston. 25

11. A suspension system according to claim 10, further including at least one accumulator operatively connected to one or both of the first hydraulic piston or second hydraulic piston, the accumulator accumulating at least a portion of a hydraulic medium used in the first and second hydraulic pistons when the first 30 or second hydraulic piston is actuated.

12. A suspension system according to claim 11, wherein the dampening force in the system can be tuned by changing the amount of a hydraulic medium in the at least one accumulator. Yaw Suspension System- complete nal 18

13. A suspension system according to claim 11 or 12, further including a first accumulator operatively connected to the first chamber of the first or second hydraulic piston and a second accumulator operatively connected to the second 5 chamber of the first or second hydraulic piston.

14. A suspension system according to any one of claims 7 to 13, further including one or more charge points in which hydraulic medium can be fed or removed from the suspension system to modify the dampening effect of the 10 suspension system.

15. A suspension system according to any one of claims 7 to 14, further including at least one pressure sensor at or near one or more accumulator for measuring the hydraulic pressure of the suspension system. 15

16. A suspension system according to any one of claims 7 to 15, further including a hydraulic connection to an external system for use in bleeding and calibrating the suspension system. 20

17. A suspension system according to any preceding claim, wherein the second body is a vehicle section of a broad acre sprayer.

18. A broadacre sprayer including a boom arrangement which is connected to a vehicle through a connection arrangement, the connection arrangement 25 including a suspension system according to any one of the preceding claims.

19. A suspension system substantially as herein described in accordance with the accompanying drawings. 30

20. A broadacre sprayer according to claim 18 substantially as herein described in accordance with the accompanying drawings. Yaw Suspension System- complete final