A baler and a method for baling material

Abstract

A belt baler (1) comprises a fixed forward part (9) and a moveable rearward part (14). The moveable rearward part (14) is operable from a bale forming state to a bale discharge state by a pair of main rams (34). A pair of tensioning rams (53) tension belts (25) of the baler (1) during formation of the bale in the bale chamber (12). Pressurised hydraulic fluid from a tractor pressurised hydraulic system 68 is applied to the main rams (34) and the tensioning rams (53) through a main spool valve (69) of the tractor (6) through a first hydraulic circuit (83) and a second hydraulic circuit (85), respectively. A pilot operated main valve (92) controls return of hydraulic fluid from the main rams (34) through the first hydraulic circuit (83) and is operated into an open state in response to pressure in the second hydraulic circuit (85) reaching a trip pressure. A secondary valve (104) in the second hydraulic circuit (85) is retained in a closed state until the moveable rearward part (14) has returned from the bale discharge state to the bale forming state in order to allow the pressure in the second hydraulic circuit (85) to rise rapidly to the trip pressure to enable the moveable rearward part (14) to return from the bale discharge state to the bale forming state without delay. On the moveable rearward part (14) having returned to the bale forming state, the secondary valve (104) is operated into the open state.

Description

[0001] A baler and a method for baling material

[0002] The present invention relates to a baler, and in particular, to a belt baler, and the invention also relates to a method for operating a belt baler, and in particular, for operating a belt baler for minimising the time taken to operate a moveable part of the baler relative to a fixed part thereof from a bale discharge state to a bale forming state after a bale has been discharged from the baler.

[0003] Belt balers are well known, in general, such belt balers comprise one or more belts carried on a plurality of rotatably mounted rollers, some of which are tensioning rollers and others of which are non-tensioning rollers. The belts are carried on the rollers to form a variable volume bale chamber in which material, for example, crop material is rotated, pressed and formed into a cylindrical bale, commonly referred to as a round bale. Such round bales, typically are of diameter in the range of 500mm to 2000mm, and more commonly are of diameter in the range of 600mm to 1900mm, and are of axial length in the range of 1000mm to 1300mm, and more commonly of axial length in the range of 1100mm to 1300mm.

[0004] In general, such belt balers comprise a fixed part and a moveable part pivotally coupled to the fixed part about an upper main pivot axis and pivotal about the main pivot axis between a bale forming state, during which a bale is formed in the bale chamber, and a bale discharge state for discharge of a formed bale from the bale chamber. A pair of main hydraulic rams located on respective opposite sides of the baler acting between the fixed part and the moveable part operate the moveable part from the bale forming state to the bale discharge state.

[0005] The fixed part carries some of the non-tensioning rollers for carrying the one or more belts, and the moveable part carries the remainder of the non-tensioning rollers. One or more of the non-tensioning rollers in the fixed part, typically, is driven for driving the one or more belts. In general, the tensioning rollers are rotatably carried on and extend between a pair of spaced apart tensioning arms pivotally coupled to the fixed part of the baler. The tensioning arms are located spaced apart on respective opposite sides of the variable volume bale chamber and in general are pivotally coupled to the fixed part about either the main pivot axis or a secondary pivot axis parallel to the main pivot axis. The tensioning arms are tensioned by both tensioning springs and tensioning rams which act between the tensioning arms and the moveable part of the baler for tensioning the one or more belts. In general, one or a pair of tensioning springs are located on each side of the baler and’one tensioning ram is located on each side of the baler. A problem with such belt balers is that as the moveable part of the baler is being urged from the bale forming state to the bale discharge state by the main rams to discharge a bale, hydraulic fluid in the tensioning rams, which had been maintaining the tension in the one or more belts, is returned to the low pressure tank of a pressurised hydraulic power source to reduce the tension in the belt or belts so that the moveable part is moveable to the bale discharge state. Therefore, when the bale has been discharged from the baler in order to enable the moveable part of the baler to return to the bale forming state, hydraulic fluid in the main rams must be returned to the low pressure tank of the pressurised hydraulic power source. The return of the hydraulic fluid from the main rams is enabled by a pilot operated main valve, which is operated into an open state in response to pressure in the hydraulic circuit applying pressurised hydraulic fluid to the tensioning rams reaching a predefined trip pressure. In order for the pressure to reach the trip pressure in the hydraulic circuit applying hydraulic fluid to the tensioning rams, the tensioning rams must first be filled with the pressurised hydraulic fluid. This in some cases may take up to three seconds, thereby, resulting in a corresponding delay before the main rams can commence returning from the bale discharge state to the bale forming state. This is undesirable.

[0006] The present invention is directed towards providing a belt baler which addresses this problem, and the invention is also directed towards a method for operating a belt baler which address the problem.

[0007] According to the invention there is provided a belt baler comprising a fixed part, and a moveable part coupled to the fixed part and moveable relative to the fixed part from a bale forming state to a bale discharge state, at least one rotatably mounted tensioning roller mounted on one of the fixed part and the moveable part, at least one belt carried on the at least one tensioning roller to define a variable volume bale chamber and to rotate, press and form material therein into a round bale, at least one main ram operably coupled between the fixed part and the moveable part and operable from a retracted state to an extended state for urging the moveable part from the bale forming state to the bale discharge state, at least one tensioning ram cooperating with the at least one tensioning roller for urging the at least one tensioning roller to tension the at least one belt, a first hydraulic circuit adapted for connecting to a pressurised hydraulic fluid source and for applying pressurised hydraulic fluid from 'the pressurised hydraulic fluid source to the at least one main ram to operate the at least one main ram from the retracted state to the extended state, a second hydraulic circuit adapted for connecting to the pressurised hydraulic fluid source and for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one tensioning ram, a main valve located in the first hydraulic circuit and being operable from a closed state for maintaining the at least one main ram pressurised in the extended state with the moveable part in the bale discharge state to an open state communicating the at least one main ram with the first hydraulic circuit to accommodate return hydraulic fluid from the at least one main ram for accommodating return of the at least one main ram from the extended state to the retracted state in response to the pressure in the second hydraulic circuit reaching or exceeding a predefined trip pressure, and a secondary valve located in the second hydraulic circuit selectively operable between an open state permitting flow of hydraulic fluid therethrough from the second hydraulic circuit to the at least one tensioning ram and a closed state preventing flow of pressurised hydraulic fluid therethrough to the at least one tensioning ram, the secondary valve being operable from the open state to the closed state prior to the commencement of delivery of pressurised hydraulic fluid through the second hydraulic fluid circuit to the at least one tensioning ram, and being operable from the closed state to the open state in response to the at least one main ram being returned to the retracted state thereof or the moveable part being returned to the bale forming state.

[0008] In one embodiment of the invention the secondary valve is operable into the closed state prior to the commencement of delivery of pressurised hydraulic fluid to the second hydraulic circuit.

[0009] In one embodiment of the invention the secondary valve is maintained in the closed state until the at least one main ram has returned to the retracted state thereof.

[0010] In one embodiment of the invention the secondary valve is maintained in the closed state until the moveable part has returned to the bale forming state.

[0011] In one embodiment of the invention the secondary valve is operable from the closed state to the open state in response to the moveable part having moved into the bale forming state from the bale discharge state.

[0012] In another embodiment of the invention the main valve is maintained in the open state in response to the pressure in the second hydraulic circuit being at or exceeding the predefined trip pressure.

[0013] Preferably, the main valve is operable from the open state to the closed state in response to the pressure in the second hydraulic circuit falling below the predefined trip pressure. In one embodiment of the invention a detecting means is provided for detecting the at least one main ram in the retracted state or the moveable part in the bale forming state, and for producing a signal indicative of the at least on main ram being in the retractable state or the moveable part being in the bale forming state, the secondary valve being operable from the closed state to the open state thereof in response to the signal produced by the detecting means being indicative of the at least one main ram having returned to the retracted state from the extended state or the moveable part being returned to the bale forming state from the bale discharge state.

[0014] In another embodiment of the invention the moveable part is retained in the bale forming state by a latch operable between a latched state latching the moveable part in the bale forming state and an unlatched state releasing the moveable part from the bale forming state, the detecting means being configured to detect the state of the latch and to produce a signal indicative of the state of the latch, the secondary valve being operable from the closed state to the open state in response to the signal from the detecting means being indicative of the latch being operated into the latched state from the unlatched state.

[0015] In another embodiment of the invention the secondary valve is operable from the open state to the closed state in response to the signal from the detecting means being indicative of the at least one main ram being in the extended state or the moveable part being in the bale discharge state.

[0016] In another embodiment of the invention the secondary valve is operable from the open state to the closed state in response to the signal from the detecting means being indicative of the latch being operated into the unlatched state.

[0017] In a further embodiment of the invention a bale wrapping means is provided for circumferentially wrapping a bale in the bale chamber on completion of formation of the bale therein, and the secondary valve is operable from the open state to the closed state thereof in response to a signal indicative of completion of circumferential wrapping of the bale in the bale chamber.

[0018] Preferably, a first non-return valve is located in the first hydraulic circuit in parallel with the main valve to accommodate pressurised hydraulic fluid through the first hydraulic circuit to the at least one main ram and to prevent return of hydraulic fluid therethrough from the at least one main ram.

[0019] Advantageously, the main valve comprises a pilot operated main valve with a pilot port of the pilot operated main valve connected to the second hydraulic circuit upstream of the secondary valve in the flow direction of pressurised hydraulic fluid through the second hydraulic circuit to the at least one tensioning ram.

[0020] In one embodiment of the invention the secondary valve is configured in the open state to permit bidirectional flow of hydraulic fluid therethrough between the second hydraulic circuit and the at least one tensioning ram.

[0021] In another embodiment of the invention the secondary valve is configured in the closed state thereof to permit flow of hydraulic fluid in a return direction from the at least one tensioning ram, and to prevent flow of hydraulic fluid to the at least one tensioning ram.

[0022] In one embodiment of the invention the second hydraulic circuit comprises a flow circuit and a return circuit connected to the at least one tensioning ram.

[0023] In one embodiment of the invention the flow and return circuits of the second hydraulic circuit are connected to the at least one tensioning ram through a common circuit.

[0024] In another embodiment of the invention the secondary valve is located in the flow circuit or in the common circuit.

[0025] Preferably, a non-return valve is located in the flow circuit of the second hydraulic circuit to prevent return of hydraulic fluid from the at least one tensioning ram through the flow circuit. Advantageously, the nonreturn valve is located in the flow circuit of the second hydraulic circuit downstream of the connection of the pilot port of the pilot operated main valve to the flow circuit in the direction of flow of hydraulic fluid towards the at least one tensioning ram.

[0026] In one embodiment of the invention the return circuit comprises a pressure limiting valve for preventing the pressure of the hydraulic fluid in the at least one tensioning ram exceeding a hydraulic density pressure for forming a bale in the bale chamber to a corresponding bale density. Preferably, the pressure limiting valve is operable in an open state for accommodating hydraulic fluid therethrough returning from the at least one tensioning ram. Preferably, the hydraulic density pressure is selectable.

[0027] In one embodiment of the invention the pressure limiting valve comprises a solenoid operated valve. Preferably, the pressure limiting valve comprises a negative normally closed proportional pressure release valve.

[0028] In one embodiment of the invention the secondary valve comprises a solenoid operated valve. Preferably, the secondary valve is operable under the control of a signal processor in response to the signal produced by the detecting means.

[0029] In one embodiment of the invention the signal processor is programmed to control the operation of the secondary valve in response to the signal indicative of completion of circumferential wrapping of a bale in the bale chamber.

[0030] Preferably, the signal processor is programmed to read the signal from the detecting means or to read the signal indicative of completion of circumferential wrapping of a bale in the bale chamber.

[0031] Advantageously, the signal processor is programmed to operate the pressure limiting valve into the open state in response to the signal indicative of completion of circumferential wrapping of the bale in the bale chamber.

[0032] In one embodiment of the invention the signal processor is responsive to a signal indicative of the hydraulic density pressure at which the pressure limiting valve is to limit the pressure of the pressurised hydraulic fluid in the at least one tensioning ram for operating the pressure limiting valve to prevent the pressure of the pressurised hydraulic fluid in the at least one tensioning ram exceeding the hydraulic density pressure.

[0033] In another embodiment of the invention the first and second hydraulic circuits are adapted for connecting to the pressurised hydraulic fluid source through a main spool valve, the main spool valve being operable in a first state for connecting the first hydraulic circuit to a high pressure side of the pressurised hydraulic fluid source and the second hydraulic circuit to a low pressure side of the pressurised hydraulic fluid source, and in a second state with the first hydraulic circuit connected to the low pressure side of the pressurised hydraulic fluid source and the second hydraulic circuit connected to the high pressure side of the pressurised hydraulic fluid source.

[0034] Preferably, in the first state of the main spool valve, the flow circuit of the second hydraulic circuit is connected to the low pressure side of the pressurised hydraulic fluid source.

[0035] Advantageously, in the second state of main spool valve, the flow circuit of the second hydraulic circuit is connected to the high pressure side of the pressurised hydraulic fluid source.

[0036] In another embodiment of the invention the main spool valve is operable in a third state with the first and second hydraulic circuits isolated from the pressurised hydraulic fluid source.

[0037] Advantageously, the return circuit of the second hydraulic circuit is connected directly to the low pressure side of the pressurised hydraulic fluid source.

[0038] In one embodiment of the invention the belt baler is adapted for towing by a tractor, and the pressurised hydraulic fluid source is derived from the pressurised hydraulic system of the tractor.

[0039] In one embodiment of the invention the main spool valve is located in the tractor and is configured for operation by a driver of the tractor.

[0040] In an alternative embodiment of the invention the main spool valve is located in the belt baler, and is operable under the control of the signal processor.

[0041] Preferably, the diameter to which the bale is formed in the bale chamber is selectable.

[0042] In one embodiment of the invention the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state to accommodate a bale from the bale chamber.

[0043] In another embodiment of the invention the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state in response to the selected diameter of the bale entered into the signal processor. Preferably, a first monitoring means is provided for monitoring the position of the at least one tensioning roller and for producing a signal indicative of the diameter of a bale in the bale chamber, the signal processor being responsive to the signal from the first monitoring means for determining completion of the formation of the bale in the bale chamber and for operating the bale wrapping means to commence circumferential wrapping of the bale in the bale chamber.

[0044] In one embodiment of the invention the signal processor is programmed to determine from the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber, the minimum displacement of the moveable part between the bale forming state and the bale discharge state thereof for accommodating discharge of a bale from the bale chamber.

[0045] In one embodiment of the invention the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state by computing the minimum displacement of the moveable part between the bale forming state and the bale discharge state as a function of the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber.

[0046] In another embodiment of the invention the signal processor is programmed to determine the minimum displacement of the moveable part between the bale forming state and the bale discharge state from a look-up table stored in an electronic memory of the signal processor or accessible to the signal processor, the look-up table comprising values of the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber cross-referenced with the corresponding values of the minimum displacement of the moveable part between the bale forming state and the bale discharge state.

[0047] In another embodiment of the invention a second monitoring means is provided for monitoring the displacement of the movable part from the bale forming state and for producing a signal indicative of the displacement of the movable part from the bale forming state.

[0048] Preferably, the signal processor is responsive to the signal produced by the second monitoring means being indicative of the moveable part being displaced from the bale forming state to the bale discharge state through the determined minimum angular displacement to operate the main spool valve or an isolating valve controlling supply of pressurised hydraulic fluid to the at least one main ram to terminate supply of pressurised hydraulic fluid to the at least one main ram. In one embodiment of the invention the moveable part is pivotally coupled to the fixed part about a main pivot axis, and is pivotal about the main pivot axis between the bale forming state and the bale discharge state.

[0049] Preferably, the at least one tensioning roller is carried on a pivotally mounted tensioning arm pivotal about a secondary pivot axis extending parallel with the main pivot axis or coinciding with the main pivot axis, and the at least one tensioning ram is co-operable with the tensioning arm for-pivoting the tensioning arm about the secondary pivot axis for tensioning the at least one belt.

[0050] Preferably, the first monitoring means is configured to monitor angular displacement of the tensioning arm about the secondary pivot axis.

[0051] Advantageously, the first monitoring means comprises a first angle sensor.

[0052] In another embodiment of the invention the second monitoring means is configured to monitor angular displacement of the movable part about the main pivot axis from the bale forming state.

[0053] Preferably, the second monitoring means comprises a second angle sensor.

[0054] In one embodiment of the invention the signal processor is responsive to completion of circumferential wrapping of the bale in the bale chamber for operating the moveable part from the bale forming state to the bale discharge state for discharging a bale from the bale chamber.

[0055] In one embodiment of the invention a pressure sensor is provided for monitoring the pressure of the hydraulic fluid in the at least one tensioning ram and for producing a signal indicative of the pressure of the hydraulic fluid in the at least one tensioning rams.

[0056] In one embodiment of the invention the predefined trip pressure at which the main valve operates from the closed state to the open state is not less than 30 bar. Preferably, the predefined trip pressure at which the main valve operates from the closed state to the open state is not less than 50 bar.

[0057] In another embodiment of the invention the predefined trip pressure lies in the range of 30 bar to 70 bar. Preferably, the predefined trip pressure is approximately 50 bar.

[0058] In one embodiment of the invention the at least one main ram comprises a single acting ram.

[0059] In another embodiment of the invention the at least one tensioning ram comprises a single acting ram.

[0060] In one embodiment of the invention a pair of main rams are provided, and preferably, the main rams are located on respective opposite sides of the baler.

[0061] In one embodiment of the invention the at least one tensioning ram acts between the at least one tensioning roller and the moveable part.

[0062] In another embodiment of the invention a plurality of tensioning rollers are provided, and preferably, the tensioning rollers are rotatably mounted on at least one tensioning arm.

[0063] In another embodiment of the invention a pair of spaced apart tensioning arms are provided, and the tensioning rollers are rotatably mounted on the tensioning arms and extend therebetween.

[0064] Preferably, the tensioning arms are located adjacent respective opposite sides of the baler.

[0065] In one embodiment of the invention a pair of the tensioning rams is provided, each tensioning ram being cooperable with a corresponding one of the tensioning arms. Preferably, the tensioning rams act between the moveable part and the respective tensioning arms.

[0066] In one embodiment of the invention at least one non-tensioning roller is provided for carrying the at least one belt, the at least one non-tensioning roller cooperating with the at least one tensioning roller and the at least one belt to define the variable volume bale chamber, and preferably, a plurality of non-tensioning rollers are provided.

[0067] In one embodiment of the invention at least one of the non-tensioning rollers is rotatably mounted in the fixed part for carrying the at least one belt, and in another embodiment of the invention at least one of the non-tensioning rollers is rotatably mounted in the moveable part for carrying the at least one belt. Preferably, a plurality of the non-tensioning rollers are rotatably mounted in the fixed part, and advantageously, a plurality of the non-tensioning rollers are rotatably mounted in the moveable part.

[0068] Preferably, at least one of the non-tensioning rollers is driven, and preferably, the at least one nontensioning roller which is driven is rotatably mounted in the fixed part.

[0069] Preferably, a plurality of belts are arranged side-by-side on the tensioning rollers, and advantageously, the belts are arranged side-by-side on the non-tensioning rollers.

[0070] In one embodiment of the invention the moveable part is pivotally coupled to the fixed part, and preferably, is pivotally coupled to the fixed part about an upper main pivot axis, and advantageously, the moveable part depends downwardly from the main pivot axis.

[0071] In one embodiment of the invention the fixed part is fixedly mounted on a chassis, and preferably, the chassis is carried on a pair of ground engaging wheels. Advantageously, the chassis is configured for hitching to a prime mover for towing thereof by the prime mover.

[0072] The invention also provides a method for minimising the time to operate a moveable part of a belt baler from a bale discharge state to a bale forming state, the belt baler comprising a fixed part and the moveable part coupled to the fixed part and moveable relative to the fixed part from the bale forming state to the bale discharge state, at least one rotatably mounted tensioning roller mounted on one of the fixed part or the moveable part, at least one belt carried on the at least one tensioning roller to define a variable volume bale chamber and to rotate, press and form material therein into a round bale, at least one main ram operably coupled between the fixed part and the moveable part and operable from a retracted state to an extended state for urging the moveable part from the bale forming state to the bale discharge state, at least one tensioning ram cooperating with the at least one tensioning roller for urging the at least one tensioning roller to tension the at least one belt, a first hydraulic circuit adapted for connecting to a pressurised hydraulic fluid source for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one main ram, a second hydraulic circuit adapted for connecting to the pressurised hydraulic fluid source for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one tensioning ram, a main valve located in the first hydraulic circuit and being operable from a closed state for maintaining the at least one main ram in the extended state with the moveable part in the bale discharge state to an open state communicating the at least one main ram with the first hydraulic circuit to accommodate return of hydraulic fluid from the at least one main ram for accommodating return of the at least one main ram from the extended state to the retracted state in response to the pressure in the second hydraulic circuit exceeding a predefined trip pressure, the method comprising applying pressurised hydraulic fluid at a pressure not less than the predefined trip pressure to the second hydraulic circuit with the at least one tensioning ram isolated from the second hydraulic circuit, and maintaining the at least one tensioning ram isolated from the second hydraulic circuit until the at least one main ram has returned to the retracted state or the moveable part has returned to the bale forming state.

[0073] In one embodiment of the invention the at least one tensioning ram is maintained isolated from the second hydraulic circuit until the at least one main ram has returned from the extended state to the retracted state.

[0074] In another embodiment of the invention the at least one tensioning ram is isolated from the second hydraulic circuit prior to the pressurised hydraulic fluid being applied to the second hydraulic circuit.

[0075] In one embodiment of the invention the at least one tensioning ram is isolated from the second hydraulic circuit by a secondary valve located in the second hydraulic circuit, the secondary valve being operable from a closed state preventing flow of pressurised hydraulic fluid to the at least one tensioning ram into an open state communicating the at least one tensioning ram with the second hydraulic circuit in response to a signal indicative of the at least one main ram having returned to the retracted state from the extended state or the moveable part having returned to the bale forming state from the bale discharge state.

[0076] In another embodiment of the invention the secondary valve is operable from the open state to the closed state in response to one of the commencement of operation of the at least one tensioning ram from the retracted state to the extended state, the at least one tensioning ram being in the extended state, the commencement of movement of the moveable part from the bale forming state to the bale discharge state, the moveable part being in the bale discharge state, or completion of circumferential wrapping of a bale in the bale chamber.

[0077] The advantages of the invention are many. A particularly important advantage of the invention is that once the bale has been discharged from the baler, the moveable part of the baler rapidly returns from the bale discharge state to the bale forming state, thereby minimising the time required for the moveable part of the baler to return to the bale forming state from the bale discharge state. This rapid return of the moveable part of the baler from the bale discharge state to the bale forming state is achieved by virtue of the fact that when pressurised hydraulic fluid is being applied to the second hydraulic circuit for applying to the tensioning rams, the secondary valve is in the closed state, thereby preventing the pressurised hydraulic fluid in the second hydraulic circuit reaching the at least one tensioning ram. This, thus, allows the pressure in the second hydraulic circuit to rise rapidly, thereby operating the main valve from the closed state to the open state to accommodate rapid return of hydraulic fluid from the at least one main ram to thereby accommodate rapid return of the moveable part from the bale discharge state to the bale forming state. Once the moveable part has returned to the bale forming state, the secondary valve is operated from the closed state to the open state to thereby apply the pressurised hydraulic fluid through the second hydraulic circuit to the at least one tensioning ram for applying tension to the at least one belt of the baler.

[0078] A further advantage of the baler according to the invention is achieved when the minimum displacement is determined through which the moveable part of the baler must be displaced from the bale forming state to the bale discharge state in order to discharge a bale from the bale chamber, in that by operating the moveable part from the bale forming state to the bale discharge state through the determined minimum displacement, the distance travelled by the moveable part from the bale forming state to the bale discharge state is minimised, thereby, minimising the time required for the moveable part to travel from the bale forming state to the bale discharge state. Additionally, the time required for the moveable part to return from the bale discharge state to the bale forming state through the determined minimum displacement is also minimised. Thus, by limiting the displacement required by the moveable part of the baler between the bale forming state and the bale discharge state, the time required to discharge a bale from the baler is further minimised, thereby, enhancing the productivity which can be gained by the baler according to the invention.

[0079] The invention will be more clearly understood from the following description of a preferred embodiment thereof which is given by way of example only with reference to the accompanying drawings, in which:

[0080] Fig. 1 is a side elevational view of a belt baler according to the invention,

[0081] Fig. 2 is another side elevational view of the belt baler of Fig. 1 illustrating a part of the belt baler of

[0082] Fig. 1 in a different state to that of Fig. 1 ,

[0083] Fig. 3 is another side elevational view of the belt baler of Fig. 1 illustrating another part of the baler in a different state to that of Fig. 1 ,

[0084] Fig. 4 is a side elevational view of the belt baler of Fig. 1 with a part of the belt baler in the state of Fig. 3, and another part of the baler in a further different state to that of Figs. 1 to 3,

[0085] Fig. 5 is a cross-sectional side elevational view of the belt baler of Fig. 1 with parts of the belt baler in the state of Fig. 2,

[0086] Fig. 6 is a cross-sectional side elevational view of the belt baler of Fig. 1 with a part of the belt baler of Fig. 1 in the state of Fig 1,

[0087] Fig. 7 is a circuit diagram of a hydraulic control circuit of the belt baler of Fig. 1 ,

[0088] Fig. 8 is a circuit diagram of a hydraulic control circuit of a belt baler according to another embodiment of the invention, and

[0089] Fig. 9 is a look-up table of the belt baler of Fig. 8.

[0090] Referring to the drawings and initially to Figs. 1 to 7 thereof, there is illustrated a belt baler according to the invention indicative generally by the reference numeral 1. The belt baler 1 is particularly suitable for rotating, pressing and forming crop material into a round bale 3, see Fig. 6, typically of diameter in the range of 1100mm to 1400mm, and of axial length in the range of 1100mm to 1300mm. Although, it will be readily apparent to those skilled in the art that the belt baler 1 may be used for rotating, pressing and forming any suitable material into a round bale. Such belt balers as the belt baler 1 will be well known to those skilled in the art, and only those parts of the belt baler 1 relevant to the invention will be described in detail.

[0091] Briefly, the belt baler 1 comprises a chassis 5 carried on a pair of rotatably mounted spaced apart main ground engaging wheels 7. A towbar 8 extends forwardly from the chassis 5 for hitching to a prime mover, for example, a tractor 6, with the towbar 8 hitched to a three-point linkage (not shown) of the tractor for towing the baler along a windrow of crop material lying in a field to be baled. The tractor 6 is illustrated in block representation in Fig. 7 only. A fixed part of the baler 1, namely, a fixed forward part 9 of the baler 1 is fixedly mounted on the chassis 5. The fixed forward part 9 comprises a pair of spaced apart side walls 10, which together define opposite ends of a forward part of a variable volume bale chamber 12, within which the bale 3 is formed. The side walls 10 of the fixed forward part 9 are retained spaced apart by a plurality of spaced apart struts (not shown) extending transversely and substantially horizontally between and sec'ured-to the side walls 10, as will be well known to those skilled in the art.

[0092] A moveable part of the baler 1 , namely, a moveable rearward part 14 comprises a pair of spaced apart side walls 15, which together define opposite ends of a rearward part of the variable volume bale chamber 12. The moveable rearward part 14 is pivotally coupled to the fixed forward part 9 about an upper horizontally extending main pivot axis 17. The moveable rearward part 14 is pivotal about the main pivot axis 17 in the direction of the arrow A from a bale forming state illustrated in Figs. 1, 2, 5 and 6, with the side walls 15 thereof defining with the side walls 10 of the fixed forward part 9 the opposite ends of the bale chamber 12, to a bale discharge state illustrated in Figs. 3 and 4 for discharge of a bale from the bale chamber 12. The side walls 15 of the moveable rearward part 14 are retained spaced apart by a plurality of spaced apart struts (also not shown) extending transversely substantially horizontally between and secured to the side walls 15, as will be well known to those skilled in the art.

[0093] A plurality of tensioning rollers, in this embodiment of the invention three tensioning rollers 18 extend between a pair of spaced apart tensioning arms 20 and are rotatably mounted and carried on the tensioning arms 20, see Figs. 5 and 6. A carrier arm 21 extending between and rigidly secured to the tensioning arms 20 retain the tensioning arms 20 spaced apart from each other within and adjacent the side walls 10 and 15 of the fixed forward part 9 and the moveable rearward part 14. A pair of coaxially aligned pivot shafts 22 extend rigidly outwardly from the tensioning arms 20 and pivotally engage the corresponding side walls 10 of the fixed forward part 9, and define a pivot axis about which the tensioning arms 20 are pivotal, which coincides with the main pivot axis 17 about which the moveable rearward part 14 is pivotal relative to the fixed forward part 9. A plurality of rotatably mounted non-tensioning rollers 23 are rotatably mounted on and extend between the side walls 10 of the fixed forward part 9, and a plurality of non-tensioning rollers 24 are rotatably mounted on and extend between the side walls 15 of the moveable part 14.

[0094] A plurality of belts 25 are carried on the tensioning rollers 18 and the non-tensioning rollers 23 and 24 and are arranged side-by-side on the rollers 18, 23 and 24. The belts 25 are carried on the tensioning rollers 18 and the non-tensioning rollers 23 and 24 to define the variable volume bale chamber 12 and to rotate, press and form crop material therein into a round bale thereof. The tensioning arms 20 and in turn the tensioning rollers 18 are operable, as will be described below, to tension the belts 25 during the formation of a bale in the bale chamber 12 and to in turn form the bale to a selectable bale density and to a selectable bale diameter. The tensioning arms 20 are pivotal about the main pivot axis 17 in the direction of the arrow B from a first state illustrated in Fig. 5 with the belts 25 tensioned prior to commencement of the formation of a bale in the bale chamber 12, to a second state illustrated in Fig. 6 with the belts 25 tensioned and defining the variable volume bale chamber 12 of maximum diameter with the formation of the bale 3 therein completed.

[0095] Two cleaning rollers 26 are provided for cleaning debris from the belts 25. One of the cleaning rollers 26 extends between and is rotatably mounted in the side walls 10 of the fixed forward part 9, and the other one of the cleaning rollers 26 extends between and is rotatably mounted in the side wails 15 of the moveable rearward part 14.

[0096] The belts 25 are driven in the direction of the arrow C for rotating the bale 3 in the bale chamber 12 in the direction of the arrow D, see Fig. 6, by one of the non-tensioning rollers 23, namely, by the non-tensioning roller 23a. The non-tensioning roller 23a is driven by a chain drive transmission (not shown). In some embodiments of the invention the belts 25 may be driven in the direction of the arrow C by two of the nontensioning rollers 23, namely, the non-tensioning rollers 23a and 23b, both of which would be driven by the chain drive transmission (not shown). The driving of belts as the belts 25 of such a belt baler as the belt baler 1 will be well known to those skilled in the art.

[0097] A pick-up and transfer mechanism 28 extends forwardly and downwardly from the chassis 5, and as the baler 1 is being towed by the tractor 6 along an elongated windrow of crop material lying on the ground, picks up the crop material from the windrow thereof and transfers the crop material into the bale chamber 12. Such a pick-up and transfer mechanism as the pick-up and transfer mechanism 28 will be well known to those skilled in the art. The pick-up and transfer mechanism 28 transfers the crop material into the bale chamber 12 between a pair of spaced apart bale rotating rollers 30 rotatably mounted in and extending between the side walls 10 of the fixed forward part 9.

[0098] The bale rotating rollers 30 and a bale rotating roller 32 extending between and rotatably mounted in the side walls 10 of the fixed forward part 9 define with the belts 25 the variable volume bale chamber 12. The bale rotating rollers 30 and 32 are driven and rotated in the direction of the arrow E by a chain drive transmission (not shown) for cooperating with the belts 25 for rotating crop material in the bale chamber 12 in the direction of the arrow D to form the bale 3, see Fig. 6.

[0099] A pair of single acting main hydraulic rams 34 acting between the fixed forward part 9 and the moveable rearward part 14, urge the moveable rearward part 14 from the bale forming state to the bale discharge state. The main rams 34 each comprise a cylinder 35 and a piston rod 36 extending from the cylinder 35. The piston rods 36 of the main rams 34 are pivotally coupled to the respective side walls 15 of the moveable rearward part 14 at 38. The cylinders 35 of the respective main rams 34 are pivotally coupled to respective latches 40 at 41 for latching and securing the moveable rearward part 14 to the fixed forward part 9 in the bale forming state. The latches 40 are pivotally coupled to the respective side walls 10 of the fixed forward part 9 by pivot pins 42, and are pivotal about the pivot pins 42 between a latched state illustrated in Figs. 1 and 2 engaging corresponding latch engagement members 44 extending sidewardly outwardly from the side walls 15 of the moveable rearward part 14 with the moveable rearward part 14 secured to the fixed forward part 9, and an unlatched state disengaged from the engagement members 44 with the moveable rearward part 14 released from the fixed forward part 9.

[0100] The single acting main rams 34 are operable to extend from a retracted state illustrated in Figs. 1 and 2 with the piston rods 36 retracted into the respective cylinders 35 and with the moveable rearward parts 14 in the bale forming state latched and secured to the fixed forward part 9 by the latches 40, to an extended state illustrated in Figs. 3 and 4 with the piston rods 36 extending outwardly from the cylinders 35 for urging the moveable rearward part 14 to the bale discharge state on supply of pressurised hydraulic fluid thereto as will be described below. The moveable rearward part 14 returns from the bale discharge state to the bale forming state substantially under its own weight on hydraulic fluid being free to return from the main rams 34 as will also be described below.

[0101] By virtue of the main rams 34 being coupled to the respective latches 40, commencement of operation of the main rams 34 from the retracted state to the extended state results in the latches .40 being urged from the latched state to the unlatched state so that on further operation of the main rams 34 from the retracted state to the extended state, the moveable rearward part 14 is urged from the bale forming state to the bale discharge state.

[0102] A pair of detecting means provided by a pair of proximity sensors 45 illustrated in Fig. 7 only, are located adjacent the latches 40 for monitoring the latched and unlatched states of the latches 40. The proximity sensors 45 produce electronic signals indicative of the latched and the unlatched states of the latches 40 for a purpose to be described below.

[0103] The pivot shafts 22 which extend outwardly from the tensioning arms 20 and pivotally engage the side walls 10 of the respective fixed forward part 9, extend sidewardiy outwardly from the corresponding side walls 10 of the fixed forward part 9. A pair of operating arms 47 rigidly secured to the pivot shaft 22 extend radially therefrom on the respective outer sides of the side walls 10 and 15 of the fixed forward part 9 and the moveable rearward part 14.

[0104] A pair of single acting hydraulic tensioning rams 53 acting between the respective operating arms 47 and the moveable rearward part 14 also act on the operating arm 47 to urge the operating arms 50 in the direction of the arrow G, and in turn the tensioning arms 20 in the direction of the arrow H, about the main axis 17 for applying tension to the belts 25 through the tensioning rollers 18 as the bale 3 is being formed in the bale chamber 12 for producing the bale 3 to a desired bale density. Each tensioning ram 53 comprises a cylinder 55 pivotally coupled to the corresponding side wall 15 of the moveable rearward part 14 adjacent a rear end 56 thereof at 57, and a piston rod 58 extending from the cylinder 55 which is pivotally connected to the corresponding operating arm 47 through a link plate 54. Each link plate 54 is pivotally coupled to the corresponding operating arm 47 at 59, and is pivotally coupled to the corresponding piston rod 58 at 61. The tensioning rams 53 are operable from an extended state illustrated in Fig. 1 with the piston rods 58 thereof extending outwardly from the cylinders 55 towards a retracted state illustrated in Fig. 2 with the piston rods 58 being retracted into the cylinders 55, in response to pressurised hydraulic fluid being supplied thereto for urging the operating arm 47 in the direction of the arrow G, and in turn the tensioning arms 20 in the direction of the arrow H to apply tension to the belts 25.

[0105] A pair of tension springs 48 act between each operating arm 47 and a bracket 50 secured to the corresponding side wall 15 of the moveable rearward part 14 adjacent a lower end 51 thereof. The tension springs 48 are configured to urge the operating arms 47 in the direction of the arrow G, to in turn urge the tensioning arms 20 about the main pivot axis 17 in the direction of the arrow H for applying tension to the belts 25 through the tensioning rollers 18 prior to the tensioning rams 53 applying tension to the belts 25 through the operating arms 47, as will be described below.

[0106] A bale wrapping system 63 which will be well known to those skilled in the art is provided for feeding either net wrapping material or plastics film wrapping material into the bale chamber 12 for circumferentially wrapping a formed bale in the bale chamber 12 prior to discharge of the bale from the bale chamber 12. The bale wrapping system 63 is configured for delivering the net wrapping material or the plastics film wrapping material between the bale forming roller 32 and the belts 25 adjacent the nontensioning roller 23c.

[0107] A first monitoring means comprising a first angle sensor 60, illustrated only in Fig. 7 in block representation, is provided for monitoring the angular displacement of the tensioning arms 20 from a datum position. The first angle sensor 60 produces an electronic signal indicative of the angular displacement of the tensioning arms 20 from the datum position thereof, which is indicative of the diameter of the bale 3 in the bale chamber 12.

[0108] Referring now to Fig. 7, a hydraulic control circuit 65 controls the operation of the main rams 34 and the tensioning rams 53. The hydraulic control circuit 65 is operated under the control of a signal processor, which in this embodiment of the invention comprises the microcontroller 67 of the baler 1, in response to signals read from the proximity sensors 45, and the first angle sensor 60. Pressurised hydraulic fluid is supplied to the hydraulic control circuit 65 from a pressurised hydraulic system 68 of the tractor 6 through a main spool valve 69 also of the tractor 6. In general, the main spool valve 69 is manually operable, and is operable in three states, as will be described below. Three high pressure releasable hydraulic couplers 70 connect the hydraulic control circuit 65 to the pressurised hydraulic system 68 of the tractor 6. The pressurised hydraulic fluid is supplied to the hydraulic control circuit 65 from the pressurised hydraulic system 68 of the tractor 6 at the system pressure (tractor system pressure) of the pressurised hydraulic system 68 of the tractor.

[0109] The main spool valve 69 comprises a pair of ports, namely, a high pressure port 72 and a low pressure port 73. The high pressure port 72 is connected to the high pressure side 75 of the pressurised hydraulic system 68, while the low pressure port 73 is connected to the low pressure side 76 of the pressurised hydraulic system 68 for returning return hydraulic fluid from the hydraulic control circuit 65 to a low pressure tank 78 of the pressurised hydraulic system 68. The hydraulic control circuit 65 is connected through two of the hydraulic couplers 70, namely, the couplers 70a and 70b to first and second ports 79 and 80, respectively. The three states in which the main spool valve 69 is operable are a first state with the first port 79 connected through to the high pressure port 72 and the second port 80 connected through to the low pressure port 73, a second state with the first port 79 connected through to the low pressure port 73 and the second port 80 is connected to the high pressure port 72. In a third state of the main spool valve 69 both of the first port 79 and second port 80 are isolated from each of the high and low pressure ports 72 and 73.

[0110] High pressure hydraulic fluid from the pressurised hydraulic fluid system 68 is applied to the main rams 34 at the tractor system pressure from the pressurised hydraulic fluid system 68 through ports 82 in the cylinders 35 thereof through a first hydraulic circuit 83 when the main spool valve 69 is in the first state thereof for operating the main rams 34 from the retracted state to the extended state for in turn urging the moveable rearward part 14 from the bale forming state to the bale discharge state. Hydraulic fluid is returned from the main rams 34 through the first hydraulic circuit 83 when the main spool valve 69 is in the second state with the first port 79 connected through to the low pressure port 73 for in turn returning the hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68. In the second state of the main spool valve 69, the weight of the moveable rearward part 14 acting on the main rams 34 urge the main rams 34 from the extended state to the retracted state to thereby return the hydraulic fluid from the main rams 34 to the low pressure side of the pressurised hydraulic system 68, and in turn to allow the moveable rearward part 14 to return from the bale discharge state to the bale forming state.

[0111] Hydraulic fluid at the tractor system pressure is supplied from the pressurised hydraulic system 68 and returned thereto through a second hydraulic circuit 85. The second hydraulic circuit 85 comprises a flow circuit 86, through which pressurised hydraulic fluid is supplied from the pressurised hydraulic system 68 to the tensioning rams 53 for tensioning the belts 25 when the main spool valve 69 is operated in the second state with the second port 80 connected through to the high pressure port 72 thereof, and a return circuit 88 through which hydraulic fluid is returned from the tensioning rams 53 to the low pressure tank 78 of the pressurised hydraulic system 68. The return circuit 88 of the second hydraulic circuit 85 is connected directly to the low pressure tank 78 of the pressurised hydraulic system 68 through a third one of the hydraulic couplers 70, namely, the coupler 70c.

[0112] Turning initially to the first hydraulic circuit 83, the pressurised hydraulic fluid is supplied to the main rams 34 through a first non-return valve 90 which is configured to permit the flow of pressurised hydraulic fluid to the main rams 34 and to prevent return of hydraulic fluid from the main rams 34, in order to maintain the main rams 34 pressurised while the moveable rearward part 14 is in the bale discharge state. A main valve comprising a pilot operated main valve 92 is located in the first hydraulic circuit 83 in parallel with the first non-return valve 90. The pilot operated main valve 92 is operable between a closed state and an open state. In the closed state, the pilot operated main valve 92 isolates the main rams 34 from the main spool valve 69, thereby preventing return of hydraulic fluid from the rams 34. In the open state of the pilot operated main valve 92, hydraulic fluid is returned from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68 when the main spool valve 69 is in the second state with the first port 79 connected to the low pressure port 73. A pilot port 91 of the pilot operated main valve 92 is connected to the flow circuit 86 of the second hydraulic circuit 85 at a node 89, and the pilot operated main valve 92 is operable from the closed state to the open state in response to the pressure in the flow circuit 86 of the second hydraulic circuit 85 reaching a predefined trip pressure value for permitting return of hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68. In this embodiment of the invention the predefined trip pressure is approximately 50 bar.

[0113] A valve 93 located in the first hydraulic circuit 83 between the parallel connected first non-return valve 90 and the pilot operated main valve 92 and the ports 82 of the main rams 34 comprises a second non-return valve 94 connected in parallel with a flow restrictor 95,- and is configured to allow substantially free-flow of the pressurised hydraulic fluid to the main rams 34 but to restrict the flow rate of return hydraulic fluid from the main rams 34 for cushioning the return of the moveable rearward part 14 from the bale discharge state to the bale forming state.

[0114] Returning now to the second hydraulic control circuit 85, the flow circuit 86 and the return circuit 88 of the second hydraulic circuit 85 are connected at a node 96, and in turn, are connected from the node 96 through a common circuit 97 to ports 98 in the cylinders 55 of the tensioning rams 53 for accommodating flow and return of hydraulic fluid between the ports 98 and the node 96. A third non-return valve 100 located in the flow circuit 86 accommodates flow of pressurised hydraulic fluid from the pressurised hydraulic system 68 of the tractor 6 to the tensioning rams 53 when the main spool valve 69 is operated in the second state with the second port 80 connected through to the high pressure port 72 thereof. The third non-return valve 100 prevents the return of hydraulic fluid from the tensioning rams 53 through the flow circuit 86, and is located in the flow circuit 86 between the nodes 89 and 96, so that when the main spool valve 69 is in the first state with the flow circuit 86 connected to the low pressure tank 78, the pilot operated main valve 92 is operated into the closed state.

[0115] A pressure limiting valve comprising a solenoid negative normally closed proportional pressure release valve 102 operable under the control of the microcontroller 67 is located in the return circuit 88, and is operable in an open circuit state for accommodating return hydraulic fluid from the tensioning rams 53 in order to relax the tension applied to the belts 25 on completion of formation and circumferential wrapping of the bale in the bale chamber 12. The proportional pressure release valve 102 is operable in a pressure limiting state for preventing the hydraulic pressure in the tensioning rams 53 exceeding a selected hydraulic density pressure for producing the bale at a desired bale density. The microcontroller 67 is responsive to a hydraulic density pressure select signal inputted thereto, as will be described below, for operating the proportional pressure release valve 102 for preventing the hydraulic pressure in the tensioning rams 53 exceeding the hydraulic density pressure. As the diameter of the bale 3 in the bale chamber 12 increases, the pressure in the tensioning rams 53 increases, and on the pressure in the tensioning rams 53 reaching the selected hydraulic density pressure, the microcontroller 67 operates the proportional pressure release valve 102 to bleed hydraulic fluid from the tensioning rams 53 to thereby limit the pressure in the tensioning rams 53 to the selected hydraulic density pressure. The bled hydraulic fluid is returned through the return circuit 88 to the low pressure tank 78 of the pressurised hydraulic system 68.

[0116] A secondary valve, in this embodiment of the invention a solenoid operated normally closed secondary valve 104 is located in the common circuit 97 between the node 96 and the ports 98 of the tensioning rams 53 and is operated under the control of the microcontroller 67. The secondary valve 104 is operable in an open state permitting bi-directional flow therethrough for accommodating pressurised hydraulic fluid to the tensioning rams 53 from the main spool valve 69 when the main spool valve 69 is in the second state, and for accommodating return hydraulic fluid from the tensioning rams 53 through the return circuit 88 to the low pressure tank 78. In the closed state, the secondary valve 104 is configured to prevent flow in a direction towards the tensioning rams 53 but to permit flow in a direction from the tensioning rams 53. Therefore, in the closed state, the secondary valve 104 prevents flow of pressurised hydraulic fluid from the pressurised hydraulic system 68 to the tensioning rams 53 but permits return of hydraulic fluid from the tensioning rams 53 through the return circuit 88 to the low pressure tank 78.

[0117] Accordingly, in order to minimise the time for the pressure in the flow circuit 86 of the second hydraulic circuit 85 to rise to the predefined trip pressure when the main spool valve 69 is operated into the second state thereof to supply pressurised hydraulic fluid through the flow circuit 86 to the tensioning rams 53, the secondary valve 104 is operated into the closed state by the microcontroller 67 prior to the main spool valve 69 being operated into the second state thereof, and the secondary valve 104 is maintained in the closed state until the moveable rearward part of the baler has returned from the bale discharge state to the bale forming state. Thus, by operating the secondary valve 104 in the closed state prior to pressurised hydraulic fluid being supplied to the flow circuit 86, the pressurised hydraulic fluid is isolated from the tensioning rams 53 by the secondary valve 104. This, thus, enables the pressure in the flow circuit 86 to rapidly rise to the target pressure for operating the pilot operated main valve 92 from the closed state to the open state. In the open state, the pilot operated main valve 92 permits hydraulic fluid from the main rams 34 to return to the low pressure tank 78 through the first hydraulic circuit 83 and in turn through the main spool valve 69 which is in the second state thereof with the first port 79 connected to the low pressure port 73. With the hydraulic fluid free to return from the main rams 34 to the low pressure tank 78, the moveable rearward part 14 returns from the bale discharge state to the bale forming state without delay. The secondary valve 104 is retained by the microcontroller 67 in the closed state until the moveable rearward part 14 has returned from the bale discharge state to the bale forming state. Once the moveable rearward part 14 has returned to the bale forming state, the microcontroller 67 operates the secondary valve 104 from the closed state to the open state, to thereby accommodate the pressurised hydraulic fluid therethrough to the tensioning rams 53 to in turn tension the belts 25 through the tensioning rollers 18.

[0118] The microcontroller 67 is responsive to the signal from the proximity sensors 45 being indicative of the latches 40 being in the latched state latching and securing the moveable rearward part 14 in the bale forming state to operate the secondary valve 104 from the closed state to the open state, in order to accommodate pressurised hydraulic fluid therethrough to the tensioning rams 53 to commence tensioning of the belts 25 for the commencement of forming the next bale. The secondary valve 104 then remains in the open state until it is operated into the closed state by the microcontroller 67 in response to the signal from the proximity sensors 45 being indicative of the latches 40 being operated into the unlatched state as the main rams 34 are about to urge the moveable rearward part 14 from the bale forming state to the bale discharge state.

[0119] By preventing flow of pressurised hydraulic fluid to the tensioning rams 53 until the moveable rearward part 14 has returned to the bale forming state, the hydraulic pressure rapidly builds in the flow circuit 86, thereby rapidly operating the pilot operated main valve 92 into the open state to permit return of hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68, to in turn allow rapid return of the moveable rearward part 14 to the bale forming state with the moveable rearward part 14 latched and secured in the bale forming state. A hydraulic accumulator 105 in the common circuit 97 accumulates hydraulic fluid from the tensioning rams 53 for balancing the hydraulic pressure in the tensioning rams 53 at the hydraulic density pressure in the event of lumps of crop material entering the bale chamber 12.

[0120] An interface which may comprise a keypad, a touch screen interface, or any other suitable interface is provided for inputting data relevant to the formation of the bale into the microcontroller 67 including the diameter to which the bale is to be formed, and the selected hydraulic density pressure of the hydraulic fluid at which the pressure in the tensioning rams 53 is to be maintained in order to produce the bale of a desired bale density, and any other information and data to be entered into the microcontroller 67. In this embodiment of the invention the interface comprises a console 107 which is located in the cab (not shown) of the tractor 6 and is hardwired to the microcontroller 67. The console 107 comprises a touch screen 108 on which data relevant to the operation of the belt baler 1 is displayed, as well as messages and instructions to the driver of the tractor 6 relating to the operation of the baler 1 and the main spool valve 69. The console 107 also comprises a sounder 110 for producing audible signals to the driver of the tractor 6. Data to be entered to the microcontroller 67, such as the diameter to which the bales are to be formed and the selected hydraulic density pressure is entered through the touch screen 108.

[0121] A pressure sensor 103 monitors pressure in the common circuit 97 and produces a signal indicative of the pressure therein, and in turn the hydraulic pressure in the tensioning rams 53, and the hydraulic pressure in the tensioning rams 53 is displayed on the touch screen 108 of the console 107.

[0122] In use, the baler 1 is hitched to a tractor 6 or other suitable towing vehicle, and is connected to the power take-off shaft of the tractor 6 for powering the mechanical drives of the baler 1, including the chain drive transmissions for transmitting drive to the non-tensioning roller 23a or the two non-tensioning rollers 23a and 23b, as well as the bale rotating rollers 30 and 32, the pick-up and transfer mechanism 28 and the bale wrapping system 63, as will be understood by those skilled in the art. The hydraulic control circuit 65 of the baler 1 is connected to the pressurised hydraulic power supply 68 of the tractor 6 through the hydraulic couplers 70a, 70b and 70c, and through the main spool valve 69 of the tractor 6.

[0123] The tractor driver before commencing baling of the crop material, initially selects and enters the hydraulic density pressure at which the proportional pressure release valve 102 is to limit the pressure of the hydraulic fluid in the tensioning rams 53 during rotating, pressing and forming the crop material in the bale chamber 12 in order to produce the bale of the desired bale density. The tractor driver also selects and enters the diameter to which the bale is to be formed.

[0124] If the moveable rearward part 14 of the baler 1 is in the bale discharge state after a previously formed and circumferentially wrapped bale has been discharged from the baler 1, the main spool valve 69 would be in the third state with the first and second ports 79 and 80 sealably isolated from each other, and sealably isolated from the high and low pressure ports 72 and 73. In this state the pressurised hydraulic fluid is retained in the main rams 34 by the first non-return valve 90 and the pilot operated main valve 92, thereby retaining the moveable rearward part 14 in the bale discharge state. The solenoid operated secondary valve 104 would be in the closed state having been operated into the closed state by the microcontroller 67 in response to the signal from the proximity sensors 45 being indicative of the latches 40 being in the unlatched state.

[0125] The tractor driver operates the main spool valve 69 from the third state into the second state thereby connecting the second port 80 through to the high pressure port 72 thereof and the first port 79 connected through to the low pressure port 73. High pressure hydraulic fluid is delivered through the second port 80 to the flow circuit 86, and the secondary valve 104 being in the closed state prevents the pressurised hydraulic fluid reaching the tensioning rams 53.

[0126] Hydraulic pressure rapidly rises in the flow circuit 86, which in turn rapidly reaches the predefined trip pressure, thereby operating the pilot operated main valve 92 into the open state, and connecting the main rams 34 through the main spool valve 69 to the low pressure tank 78 of the pressurised hydraulic fluid system 68. With the main rams 34 connected to the low pressure tank 78, the moveable rearward part 14 pivots about the main pivot axis 17 from the discharge state to the bale forming state under its own weight and under pressure applied thereto by the tensioning springs 48. On the signal from the proximity sensors 45 being indicative of the latches 40 being in the latched state and thus the moveable rearward part 14 being latched and secured in the bale forming state, the microcontroller 67 operates the secondary valve 104 from the closed state into the open state in order to permit flow of pressurised hydraulic fluid from the pressurised hydraulic system 68 through the flow circuit 86 and the common circuit 97 to the tensioning rams 53.

[0127] Once the moveable rearward part 14 is in the bale forming state, the tractor driver may then commence to tow the baler 1 along a windrow of crop material, which is then picked up by the pick-up and transfer mechanism 28 and is delivered into the bale chamber 12 between the bale rotating rollers 30. If the hydraulic pressure in the tensioning rams 53 has not reached the selected hydraulic density pressure as the tractor driver commences to tow the baler along the windrow of crop material, the tensioning pressure applied by the tensioning springs 48 to the operating arms 47 of the carrier shaft 21 is initially sufficient to apply sufficient tension to the belts 25 and in turn to the belts 25 for applying sufficient pressure to the crop material in the bale chamber 12 to permit initial formation of the crop material in the bale chamber 12 until the rotating crop material in the bale chamber 12 reaches a diameter of approximately 650mm, at which stage the tensioning rams 53 will have been fully charged with pressurised hydraulic fluid, and the pressure thereof will have reached, and be maintained at the selected hydraulic density pressure by the proportional pressure release valve 102.

[0128] Once the signal from the pressure sensor 103 which is indicative of the pressure of the hydraulic fluid in the tensioning rams 53, and which is displayed on the touch screen 108 of the console 107 is indicative of the pressure in the tensioning rams 53 having reached the selected hydraulic density pressure, the tractor driver operates the main spool valve 69 from the second state to the third state in order to isolate both the first and second ports 79 and 80 thereof from the high pressure and low pressure ports 72 and 73 thereof. With the first and second ports 79 and 80 isolated from the high and low pressure ports 72 and 73, the proportional pressure release valve 102 operating under the control of the microcontroller 67 limits the pressure in the tensioning rams 53 from exceeding the selected hydraulic density pressure.

[0129] As the crop material is being delivered into the bale chamber 12, the crop material is rotated therein by the cooperating action of the bale rotating rollers 30 and 32 and the belts 25. As crop material is progressively urged into the bale chamber 12 between the bale rotating rollers 30, the diameter of the bale 3 commences to progressively increase and in turn the diameter of the bale chamber 12 correspondingly progressively increases. The pressure of the hydraulic fluid in the tensioning rams 53 is prevented from exceeding the selected hydraulic density pressure by the proportional pressure release valve 102 under the control of the microcontroller 67, so that the baie is formed to the desired bale density

[0130] The microcontroller 67 reads the signals from the first angle sensor 60 and determines from the signal read from the first angle sensor 60 the diameter of the. bale in the bale chamber 12. On the microcontroller 67 determining from the first angle sensor 60 that the bale in the bale chamber 12 is at the selected diameter, the microcontroller 67 outputs a signal to a console 107 to display a message on the touch screen 108 indicating to the tractor driver that the bale has been formed to the desired diameter and to stop the tractor 6, so that the formed bale in the bale chamber 12 may be circumferentially wrapped. The signal outputted to the console 107 also activates the sounder 110 to produce an alert signal drawing the tractor driver’s attention to the message on the touch screen 108 of the console 107. With the baler stopped, the microcontroller 67 operates the bale wrapping system 63 to circumferentially wrap the bale in the bale chamber 12.

[0131] On completion of circumferentially wrapping of the bale, the microcontroller 67 outputs a further signal to the console 107 in the cab of the tractor 6 to display a message on the touch screen 108 indicating to the driver the completion of the circumferential wrapping of the bale. The tractor driver then operates the main spool valve 69 from the third state to the first state with the first port 79 connected through to the high pressure port 72 and the second port 80 connected through to the low pressure port 73.

[0132] With the main spool valve 69 in the first state, pressurised hydraulic fluid is delivered through the first hydraulic circuit 83 through the first non-return valve 90 to the main rams 34 for operating the moveable rearward part 14 from the bale forming state to the bale discharge state. On the signal from the proximity sensors 45 being indicative of the latches 40 being in the unlatched state, the microcontroller 67 operates the proportional pressure release valve 102 into the open state to connect the tensioning rams 53 to the low pressure tank 78 of the pressurised hydraulic system 68 through the return circuit 88 to accommodate return of hydraulic fluid from the tensioning rams 53 to the low pressure tank 78, to in turn relieve the tension in the belts 25. Additionally, the microcontroller 67 operates the secondary valve 104 from the open state to the closed state. Operating the secondary valve 104 into the closed state does not prevent the return of hydraulic fluid from the tensioning rams 53 to the low pressure tank 78, since in the closed state the secondary valve 104 permits return of hydraulic fluid from the tensioning rams 53 therethrough to the low pressure tank 78. With the moveable rearward part 14 in the bale discharge state, the bale is discharged from the baler 1 onto the ground, or if the baler comprises a bale wrapper in combination with the baler, the circumferentially wrapped bale is transferred from the baler 1 onto the bale wrapping for end-to-end wrapping thereof, and the driver operates the main spool valve into the third state thereof.

[0133] With the bale discharged from the baler 1, the tractor driver operates the main spool valve 69 from the third state to the second state with the first port 79 connected through to the low pressure port 73 thereof and the second port 80 connected through to the high pressure port 72 thereof for delivering pressurised hydraulic fluid from the pressurised hydraulic system 68 to the flow circuit 86 of the second hydraulic circuit 85 to in turn operate the pilot operated main valve 92 from the closed state into the open state for the return of hydraulic fluid from the main rams 34 to the low pressure tank 78, in order to permit the moveable rearward part 14 to pivot about the main pivot axis 17 from the bale discharge state to the bale forming state.

[0134] On the moveable rearward part 14 of the baler 1 returning to the bale forming state and being latched and secured in the bale forming state by the latches 40, the signal from the proximity sensors 45 is indicative of the latches 40 being in the latched state. On the microcontroller 67 detecting the signal from the proximity sensors 45 being indicative of the latches 40 being in the latched state, the microcontroller 67 operates the secondary valve 104 from the closed state to the open state to accommodate the pressurised hydraulic fluid from the pressurised hydraulic system 68 through tb the tensioning rams 53, and so operation of the belt baler 1 continues in the formation of the next bale.

[0135] As mentioned above, a particularly important advantage of the invention is that once the bale has been discharged from the baler, the moveable rearward part 14 of the baler is rapidly returned from the bale discharge state to the bale forming state. This is achieved by virtue of the fact that once the main spool valve is operated to return the moveable rearward part 14 to the bale forming state, and to apply pressurised hydraulic fluid to the tensioning rams 53, the secondary valve 104 is in the closed state, thereby isolating the tensioning rams 53 from the flow circuit 86 of the second hydraulic circuit 85 which in turn allows the hydraulic pressure to rapidly increase in the flow circuit 86 of the second hydraulic circuit 85 to the predefined trip pressure. This in turn rapidly operates the pilot operated main valve 92 from the closed state to the open state, thereby permitting rapid return of hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic fluid system 68, which in turn results in rapid return of the moveable rearward part 14 from the bale discharge state to the bale forming state.

[0136] Once the rearward moveable part 14 has returned to the bale forming state, the secondary valve 104 is operated from the closed state to the open state, thereby accommodating pressurised hydraulic fluid from the flow circuit 86 of the second hydraulic circuit 85 to the tensioning rams 53 for in turn tensioning the belts 25. The fact that the delivery of pressurised hydraulic fluid to the tensioning rams 53 is delayed until the moveable rearward part 14 has returned to the bale forming state does not have any adverse effect on the formation of the bale in the bale chamber 12, even if towing of the baler along the windrow of crop material commences immediately the moveable rearward part of the baler is latched in the bale forming state, due to the fact that the tensioning springs 48 apply tension to the tensioning arms 20, and in turn to the belts 25 until the bale and in turn the bale chamber 12 have reached a diameter of approximately 650 millimetres. By the time the diameter of the bale and in turn the diameter of the bale chamber 12 have reached the diameter of 650 millimetres, the tensioning rams 53 will have been fully pressurised for tensioning the belts 25.

[0137] Referring now to Figs. 8 and 9 there is illustrated a hydraulic control circuit indicated generally by the reference numeral 120 for a belt baler also according to the invention and indicated generally by the reference numeral 121. The belt baler 121 is illustrated in block representation only in Fig. 8. However apart from the control circuit 120 of the belt baler 121, the belt baler 121 is similar to the belt baler 1 illustrated in Figs. 1 to 6, of and accordingly, no further illustrations of the belt baler 121 should be required. The components of the belt baler 121 will be referred to by the same reference numerals as those of the belt baler 1 of Figs. 1 to 6. In this embodiment of the invention the belt baler 1 is essentially an automatic belt baler, and the only input required from the driver of the tractor 6 towing the belt baler 121 is to bring the belt baler 121 to a halt so that the bale of crop material in the bale chamber 12 may be circumferentially wrapped, and so that the circumferentially wrapped bale may be discharged from the belt baler 121. Once the circumferentially wrapped bale has been discharged from the belt baler 121 and the moveable rearward part 14 of the belt baler 121 has been returned to the bale forming state after discharge of the circumferentially wrapped bale, the tractor driver is then required to commence towing the baler 121 along a windrow of crop material for forming the next bale.

[0138] Turning now to the hydraulic control circuit 120, and referring to Figs. 8 and 9, the hydraulic control circuit 120 is substantially similar to the hydraulic control circuit 65 of the belt baler 1, and similar components are identified by the same reference numerals. The main difference between the hydraulic control circuit 120 and the hydraulic control circuit 65 is that the hydraulic control circuit 120 comprises a solenoid operated main spool valve 123. The solenoid operated main spool valve 123 is operated under the control of the microcontroller 67 and controls the supply of pressurised hydraulic fluid from the pressurised hydraulic system 68 of the tractor 6 to the first and second hydraulic circuits 83 and 85, and the return of hydraulic fluid from the first hydraulic circuit 83 to the pressurised hydraulic system 68 of the tractor 6. Accordingly, the solenoid operated main spool valve 123 of the belt baler 121 operates in place of the main spool valve 69 of the tractor 6 described with reference to the belt baler 1 , as will be described below.

[0139] The solenoid operated main spool valve 123 is operated under the control of the microcontroller 67 in a substantially similar manner as the main spool valve 69 located in the tractor 6 was described for operating the belt baler 1 with reference to Figs. 1 to 7. Accordingly, in this embodiment of the invention the hydraulic control circuit 120 is connected to the pressurised hydraulic system 68 of the tractor through two hydraulic couplers, namely, hydraulic couplers 125a and 125b, and thus the supply and return of hydraulic fluid between the pressurised hydraulic system 68 of the tractor 6 and the hydraulic control circuit 120 bypasses the main spool valve 69 of the tractor 6.

[0140] The solenoid operated main spool valve 123 comprises a high pressure port 127 which is connected by a high pressure line 124 to the high pressure side 75 of the pressurised hydraulic system 68 of the tractor 6 through the hydraulic coupler 125a, and a low pressure port 128 which is connected by a low pressure line 126 to the low pressure side 76 and in turn to the low pressure tank 78 of the pressurised hydraulic system 68 through the hydraulic coupler 125b. A first port 129 and a second port 130 of the solenoid operated main spool valve 123 are connected to the first hydraulic circuit 83, and to the flow circuit 86 of the second hydraulic circuit 85, respectively.

[0141] Like the main spool valve 69 of the tractor 6 described with reference to the belt baler 1, the solenoid controlled main spool valve 123 is operable in three states similar to the three states in which the main spool valve 69 is operable in.

[0142] In the first state of the solenoid operated main spool valve 123, the first port 129 is connected to the high pressure port 127 and in turn to the high pressure side 75 to the pressurised hydraulic system 68 of the tractor 6 for operating the main rams 34 from the retracted state to the extended state, for in turn urging the moveable rearward part 14 of the baler 121 from the bale forming state to the bale discharge state. Additionally, in the first state of the solenoid operated main spool valve 123 the second port 130 is connected to the low pressure port 128 of the solenoid operated main spool valve 123, which in turn is connected through the hydraulic coupler 125b to the low pressure side 76 of the pressurised hydraulic system 68.

[0143] In the second state of the solenoid operated main spool valve 123, the first port 129 is connected to the low pressure port 128 for accommodating return of hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68 of the tractor 6. In the second state of the solenoid operated main spool valve 123, the second port 130 is connected to the high pressure port 127 for applying pressurised hydraulic fluid from the pressurised hydraulic system 68 of the tractor 6 to the flow circuit 86 of the second hydraulic circuit 85, to operate the pilot operated mairnvalve 92 from the closed state to the open state to accommodate hydraulic fluid from the main rams 34 to the low pressure tank 78 of the pressurised hydraulic system 68, and when the secondary valve 104 is operated from the closed state to the open state to apply the pressurised hydraulic fluid to the tensioning rams 53.

[0144] The solenoid operated main spool valve 123 is operated in the third state similar to that of the main spool valve 69 in which the first and second ports 129 and 130 are isolated from each other and are also isolated from the high pressure and low pressure ports 127 and 128.

[0145] In this embodiment of the invention since the hydraulic control circuit 120 comprises the solenoid operated main spool valve 123, the return circuit 88 of the second hydraulic circuit 85 is connected to the low pressure return line 126 between the low pressure port 128 of the solenoid operated main spool valve 123 and the hydraulic coupler 125b at a node 132.

[0146] Additionally in this embodiment of the invention the belt baler 121 is provided with a second monitoring means for monitoring displacement of the moveable rearward part 14 from the bale forming state. In this case, the second monitoring means comprises a second angle sensor 134 for monitoring the angular displacement of the moveable rearward part 14 about the main pivot axis 17 from the bale forming state. The second angle sensor 134 is configured to produce a signal indicative of the angular displacement of the moveable rearward part 14 from the bale forming state. The microcontroller 67 is programmed to read the signal from the second angle sensor 134, and to determine the angular displacement of the moveable rearward part 14 from the bale forming state as the moveable rearward part 14 is being urged by the main rams 34 from the bale forming state to the bale discharge state for discharging a bale from the baler 121.

[0147] In this embodiment of the invention as well as the baler 121 being operated to minimise the time required for the moveable rearward part 14 to return from the bale discharge state to the bale forming state as already described with reference to the baler 1, the control circuit 120 is also configured to minimise the angular displacement of the moveable rearward part 14 from the bale forming state to the bale discharge state required for discharging a bale from the baler. Thereby in this embodiment of the invention the time required to discharge a bale from the baler 121 is further minimised.

[0148] The microcontroller 67 as described with reference to the baler 1 is programmed to determine the diameter of the bale in the bale chamber 12 from the signal read from the first angle sensor 60. The microcontroller 67 is programmed, based on the determined diameter of the circumferentially wrapped bale in the bale chamber 12, to determine the minimum displacement of the moveable rearward part 14 from the bale forming state to the bale discharge state sufficient to accommodate a bale of the determined diameter from the bale chamber 12, which in this embodiment of the invention is the minimum angular displacement of the moveable rearward part 14 from the bale forming state to the bale discharge state in order to accommodate the circumferentially wrapped bale from the baler 121. A look-up table 135 is stored in an electronic memory 137 of the microcontroller 67, or accessible to the microcontroller 67, which may be any suitable electronic memory, for example, a read only memory or a random access memory. The look-up table 135 is illustrated in Fig. 9 and stores a plurality of values of bale diameters, in this case, ten bale diameter values Di to D10cross-referenced with corresponding values of minimum angular displacements 61 to 6 corresponding to the bale diameters Di to D , through which the moveable rearward part 14 must pivot about the main pivot axis 17 from the bale forming state to the bale discharge state to accommodate discharge of a circumferentially wrapped bale of the corresponding diameter from the bale chamber 12.

[0149] On completion of circumferential wrapping of the bale in the bale chamber 12 of the baler 121, the microcontroller 67 reads the signal from the first angle sensor 60, and determines the diameter D of the circumferentially wrapped bale. The microcontroller 67 is programmed to then determine the minimum angular displacement 6 of the moveable rearward part 14 from the bale forming state to the bale discharge state required to discharge the bale of the determined diameter D from the baler 121 from the look-up table 135 corresponding to the determined diameter D of the circumferentially wrapped bale. Having determined the appropriate minimum angular displacement from the look-up table 135 through which the moveable rearward part 14 of the baler 121 must pivot about the main pivot axis 17 from the bale forming state to the bale discharge state, the microcontroller 67 monitors the signal from the second angle sensor 134 as the main rams 34 are urging the moveable rearward part 14 from the bale forming state for discharging the bale from the baler 121. On the signal read from the second angle sensor 124 being indicative of the moveable rearward part 14 having pivoted through the determined minimum angular displacement 0, the microcontroller 67 operates the solenoid operated main spool valve 123 into the third state thereby preventing further angular displacement of the moveable rearward part 14 from the bale forming state, and the bale is discharged from the baler 121 by the action of the belts 25 on the bale and gravity. The microcontroller 67 then operates the solenoid operated main spool valve 123 from the third state to the second state in a similar manner as already described with reference to the main spool valve 69 described with reference to the baler 1 for returning the main rams 34 from the bale discharge state to the bale forming state, so that the tractor driver on the moveable rearward part 14 having returned to the bale forming state can commence towing the baler along the windrow of crop material to form the next bale.

[0150] In this embodiment of the invention the microcontroller 67 is programmed to output two signals to the console 107. A first signal of the two signals is configured to display a message on the touch screen 108 to the tractor driver instructing the tractor driver to bring the baler 121 to a halt, so that circumferential wrapping of the bale in the bale chamber 12 may commence. A second signal of the two signals is configured to display a message on the touch screen 108 advising the tractor driver that the moveable rearward part 14 is in the bale forming state and latched and secured therein by the latches 40, and instructing that the baler 121 is ready to be towed along the windrow of crop material to form the next bale. Each of the first and second signals outputted by the microcontroller 67 to the console 107 activates the sounder 110 to produce an audible alert signal to the tractor driver advising that a message is being displayed on the touch screen 108.

[0151] Otherwise, the belt baler 121 and its operation are similar to the belt bale 1 and its operation.

[0152] The advantages of the baler 121 are similar to the advantages achieved by the baler 1 , with the added advantage that since the moveable rearward part 14 of the baler is only operated through the minimum angular displacement from the bale forming state to the bale discharge state sufficient to accommodate discharge of a bale from the baler 121 corresponding to the diameter of the circumferentially wrapped bale, the angular displacement of the moveable rearward part 14 from the bale forming state to the bale discharge state, as well as the angular displacement of the moveable rearward part from the bale discharge state to the bale forming state are both minimised, thereby minimising the travel time of the moveable rearward part from the bale forming state to the bale discharge state and back to the bale forming state. This advantage is achieved on top of the advantage gained by preventing flow of pressurised hydraulic fluid to the tensioning rams by operating the secondary valve 104 in the closed state until the moveable rearward part 14 has returned to the bale forming state.

[0153] It is also envisaged that in some embodiments of the invention an additional solenoid operated isolating valve may be located in the first hydraulic circuit 85, which would be operated from an open state to a closed state under the control of the microcontroller 67, to terminate the supply of pressurised hydraulic fluid to the main rams 34 on the main rams 34 having displaced the moveable rearward part through the minimum angular displacement from the bale forming state to the bale discharge state corresponding to the diameter of the circumferentially wrapped bale. The provision of such a solenoid operated valve may possibly more accurately stop the pivotal movement of the moveable rearward part 14 once the rearward moveable part 14 had pivoted through the minimum angular displacement from the bale forming state.

[0154] It will also be appreciated that instead of providing a solenoid operated main spool valve to control the supply and return of hydraulic fluid between the pressurised hydraulic system 68 and the first and second hydraulic circuits 83 and 85 of the baler 121, the solenoid operated main spool valve 123 may be replaced by a suitable number of solenoid operated valves which would fulfil the functions carried out by the solenoid operated main spool valve 123 and which would be operated under the control of the microcontroller 67.

[0155] It is envisaged in some embodiments of the invention that instead of providing a look-up table with bale diameter values cross-referenced with minimum angular displacement values, the microcontroller 67 may be programmed to compute the appropriate minimum angular displacement of the moveable rearward part 14 of the baler 121 as a function of the determined diameter of the circumferentially wrapped bale by inserting the determined diameter or a value indicative of the determined diameter of the circumferentially wrapped bale into a suitable equation, which would produce the corresponding minimum angular displacement.

[0156] While the look-up table has been described as comprising diameter values of the circumferentially wrapped bale cross-referenced with minimum displacement values, it is envisaged. in some embodiments of the invention that instead of the look-up table comprising actual diameters of the circumferentially wrapped bale, the look-up table may comprise values indicative of the diameters of the circumferentially wrapped bale. Similarly, it is envisaged that in some embodiments of the invention the look-up table, instead of comprising corresponding values of minimum angular displacements, may comprise values indicative of minimum angular displacements.

[0157] While the look-up table has been described as comprising ten bale diameter values cross-referenced with ten corresponding minimum angular displacement values, it is envisaged that the look-up table may comprise any number of bale diameter values cross-referenced with corresponding numbers of minimum angular displacement values. Indeed, it is envisaged that the number of bale diameter values and corresponding values of minimum angular displacements may range from two, three, four or more up to fifty, one hundred or even more than one hundred diameter values. In the embodiment of the belt baler described with reference to Figs. 8 and 9, it is envisaged that instead of determining the minimum angular displacement of the moveable rearward part of the baler from the bale forming state to the bale discharge state based on the diameter of the bale read from the first angle sensor, the minimum angular displacement of the moveable rearward part of the baler from the bale forming state to the bale discharge state, may be determined from the selected diameter of the bale entered into the microcontroller.

[0158] While the secondary valve 104 has been described as comprising a solenoid operated normally open valve and in the closed state thereof permits return of hydraulic fluid from the tensioning rams, while this is desirable, any other suitable secondary valve may be provided. Indeed, it is envisaged that a solenoid operated normally open valve which in the closed state thereof prevented flow in both the flow and return directions could be provided if such a valve were located in the flow circuit 86 between the node 96 and the node 89 at which the pilot port 91 of the pilot operated main valve 92 is connected to the flow circuit 86.

[0159] It is also envisaged that in some embodiments of the invention, if the microcontroller is not programmed to control the operation of the proportional pressure release valve 102 to limit the pressure in the tensioning rams 53 to selectable hydraulic density pressures to produce bales of selectable bale densities, the proportional pressure release valve 102 may be replaced with a valve comprising a manually operated pressure release mechanism, which would enable the upper pressure at which the valve would commence to open to be selectable for limiting the pressure in the tensioning rams 53 at selectable hydraulic density pressures.

[0160] While the hydraulic control circuit 65 of the belt baler has been described for connecting to the pressurised hydraulic system 68 of a tractor through the main spool valve 69 of the tractor, it is envisaged that in some embodiments of the invention the hydraulic control circuit 65 may include a main spool valve, and in which case, the main spool valve would be operated under the control of the microcontroller 67. The main spool valve in this case may be a solenoid operated main spool valve, or the main spool valve may be replaced by separate valves, typically, solenoid operated valves which together would fulfil the functions of the main spool valve, and would be operated under the control of the microcontroller 67. In embodiments of the invention in which the main spool valve or equivalent valves are incorporated into the hydraulic control circuit, only two hydraulic lines would be required to couple the hydraulic control circuit 65 to the pressurised hydraulic system 68 of the tractor with the’main spool valve of the tractor bypassed. One of the hydraulic lines would couple the high pressure port of the main spool valve or equivalent valve, now in the hydraulic control circuit, with the high pressure side of the pressurised hydraulic system of the tractor, and the other hydraulic line would couple the low pressure port of the main spool valve or equivalent valve with the low pressure side of the pressurised hydraulic system of the tractor. These two hydraulic lines would include respective releasable hydraulic couplers for releasably connecting the hydraulic control circuit of the baler with the pressurised hydraulic system of the tractor. The return circuit 88 of the second hydraulic circuit 85 would be connected by a T-connector into the hydraulic line connecting the low pressure port of the main spool valve or equivalent valve with the low pressure side of the pressurised hydraulic system of the tractor, between the low pressure port of the main spool valve or equivalent valve and the corresponding hydraulic coupler.

[0161] It will also be appreciated that while respective pairs of tensioning springs have been provided for tensioning the tensioning arms, in some embodiments of the invention a single pair of tensioning springs may be sufficient with one of the springs of the single pair thereof located on one side of the baler and the other one of the springs located on the other side of the baler. In other cases, it is envisaged that a single tensioning spring may be sufficient and would be applied to a single corresponding operating arm 47. It is also envisaged that while two tensioning rams have been described connected to the respective operating arm, in some embodiments of the invention a single tensioning ram connecting to a single operating arm may be sufficient

[0162] It is also envisaged that while two main rams have been described, a single main ram may be sufficient for operating the moveable rearward part 14 from the bale forming state to the bale discharge state. Furthermore, it will be appreciated that while it is desirable to couple each main ram to the fixed forward part of the baler through the corresponding latch for latching the moveable rearward part 14 in the bale forming state, in some embodiments of the invention the main ram or rams may be pivotally coupled directly onto the fixed forward part of the baler, and other suitable latch operating means may be provided for operating the latches from the latched state to the unlatched state.

[0163] Needless to say, any other suitable arrangement and construction of tensioning arms may be provided, and any other arrangement of tensioning rollers and non-tensioning rollers besides those described may be provided. It is also envisaged that instead of operating the secondary valve from the open state to the closed state in response to the signals from the proximity sensors indicative of the latches being operated from the latched state to the unlatched state as the main rams commence to extend from the retracted state to the extended state, the secondary valve may be operated from the open state to the closed state in response to a signal from a suitable sensor being indicative of the moveable rearward part of the baler being in the bale discharge state. Alternatively, the secondary valve may be operated from the open state to the closed state in response to circumferential wrapping of the bale in the bale chamber.

[0164] While the microcontroller has been described as being programmed to enable the hydraulic density pressure to which the hydraulic pressure in the tensioning rams is limited for producing the bales of a desired bale density, it is envisaged that in some embodiments of the invention the microcontroller may be programmed to enable a selection of the desired bale density of the bale to be entered into the microcontroller through the interface. In which case, it is envisaged that a plurality of look-up tables would be stored in the microcontroller or in a memory accessible to the microcontroller which would crossreference selectable bale densities with corresponding hydraulic density pressures for different types of crop material, and also for different types of crop material of different moisture contents.

[0165] While the signal processor has been described as comprising a microcontroller, the signal processor may be provided by any suitable signal processor, for example, a microprocessor, a programmable logic controller or indeed any other suitable signal processor. It is also envisaged that where the signal processor is provided by a microcontroller, the microcontroller need not be the microcontroller controlling the belt baler, it may be a separate microcontroller, or a separate programmable logic controller or a separate signal processor, which typically, would communicate with the microcontroller or other signal processor controlling the operation of the baler.

[0166] It is also envisaged that in some embodiments of the invention the main valve, instead of comprising a pilot operated main valve, may instead be provided by'a solenoid operated valve which would be operated by the microcontroller in response to the signal read from the proximity sensors or other suitable sensors for determining the state of the main rams, the latches which latch the moveable rearward part of the baler to the fixed forward part thereof, the state of the moveable rearward part, or the state of the circumferential wrapping of the bale in the bale chamber.

Claims

Claims1. A belt baler comprising a fixed part, and a moveable part coupled to the fixed part and moveable relative to the fixed part from a bale forming state to a bale discharge state, at least one rotatably mounted tensioning roller mounted on one of the fixed part and the moveable part, at least one belt carried on the at least one tensioning roller to define a variable volume bale chamber and to rotate, press and form material therein into a round bale, at least one main ram operably coupled between the fixed part and the moveable part and operable from a retracted state to an extended state for urging the moveable part from the bale forming state to the bale discharge state, at least one tensioning ram cooperating with the at least one tensioning roller for urging the at least one tensioning roller to tension the at least one belt, a first hydraulic circuit adapted for connecting to a pressurised hydraulic fluid source and for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one main ram to operate the at least one main ram from the retracted state to the extended state, a second hydraulic circuit adapted for connecting to the pressurised hydraulic fluid source and for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one tensioning ram, a main valve located in the first hydraulic circuit and being operable from a closed state for maintaining the at least one main ram pressurised in the extended state with the moveable part in the bale discharge state to an open state communicating the at least one main ram with the first hydraulic circuit to accommodate return hydraulic fluid from the at least one main ram for accommodating return of the at least one main ram from the extended state to the retracted state in response to the pressure in the second hydraulic circuit reaching or exceeding a predefined trip pressure, and a secondary valve located in the second hydraulic circuit selectively operable between an open state permitting flow of hydraulic fluid therethrough from the second hydraulic circuit to the at least one tensioning ram and a closed state preventing flow of pressurised hydraulic fluid therethrough to the at least one tensioning ram, the secondary valve being operable from the open state to the closed state prior to the commencement of delivery of pressurised hydraulic fluid through the second hydraulic fluid circuit to the at least one tensioning ram, and being operable from the closed state to the open state in response to the at least one main ram being returned to the retracted state thereof or the moveable part being returned to the bale forming state.

2. A belt baler as claimed in Claim 1 in which a detecting means is provided for detecting the at least one main ram in the retracted state or the moveable part in the bale forming state, and for producing a signal indicative of the at least on main ram being in the retractable state or the moveable part being in the bale forming state, the secondary valve being operable from the closed state to the open state thereof in response to the signal produced by the detecting means being indicative of the at least one main ramhaving returned to the retracted state from the extended state or the moveable part being returned to the bale forming state from the bale discharge state.

3. A belt baler as claimed in Claim 2 in which the moveable part is retained in the bale forming state by a latch operable between a latched state latching the moveable part in the bale forming state and an unlatched state releasing the moveable part from the bale forming state, the detecting means being configured to detect the state of the latch and to produce a signal indicative of the state of the latch, the secondary valve being operable from the closed state to the open state in response to the signal from the detecting means being indicative of the latch being operated into the latched state from the unlatched state.

4. A belt baler as claimed in Claim 2 or 3 in which the secondary valve is operable from the open state to the closed state in response to the signal from the detecting means being indicative of the at least one main ram being in the extended state or the moveable part being in the bale discharge state.

5. A belt baler as claimed in any of Claims 2 to 4 in which the secondary valve is operable from the open state to the closed state in response to the signal from the detecting means being indicative of the latch being operated into the unlatched state.

6. A belt baler as claimed in any preceding claim in which a bale wrapping means is provided for circumferentially wrapping a bale in the bale chamber bn completion of formation of the bale therein, and the secondary valve is operable from the open state to the closed state thereof in response to a signal indicative of completion of circumferential wrapping of the bale in the bale chamber.

7. A belt baler as claimed in any preceding claim in which the main valve is maintained in the open state in response to the pressure in the second hydraulic circuit being at or exceeding the predefined trip pressure.

8. A belt baler as claimed in any preceding claim in which the main valve is operable from the open state to the closed state in response to the pressure in the second hydraulic circuit falling below the predefined trip pressure.

9. A belt baler as claimed in any preceding claim in which a first non-return valve is located in thefirst hydraulic circuit in parallel with the main valve to accommodate pressurised hydraulic fluid through the first hydraulic circuit to the at least one main ram and to prevent return of hydraulic fluid therethrough from the at least one main ram.

10. A belt baler as claimed in any preceding claim in which the main valve comprises a pilot operated main valve with a pilot port of the pilot operated main valve connected to the second hydraulic circuit upstream of the secondary valve in the flow direction of pressurised hydraulic fluid through the second hydraulic circuit to the at least one tensioning ram.

11. A belt baler as claimed in any preceding claim in which the secondary valve is configured in the open state to permit bi-directional flow of hydraulic fluid therethrough between the second hydraulic circuit and the at least one tensioning ram.

12. A belt baler as claimed in any preceding claim in which the secondary valve is configured in the closed state thereof to permit flow of hydraulic fluid in a return direction from the at least one tensioning ram, and to prevent flow of hydraulic fluid to the at least one tensioning ram.

13. A belt baler as claimed in any preceding claim in which the second hydraulic circuit comprises a flow circuit and a return circuit connected to the at least one tensioning ram.

14. A belt baler as claimed in Claim 13 in which the flow and return circuits of the second hydraulic circuit are connected to the at least one tensioning ram through a common circuit.

15. A belt baler as claimed in Claim 13 or 1 in which the secondary valve is located in the flow circuit or in the common circuit.

16. A belt baler as claimed in any of Claims 13 to 15 in which a non-return valve is located in the flow circuit of the second hydraulic circuit to prevent return of hydraulic fluid from the at least one tensioning ram through the flow circuit.

17. A belt baler as claimed in Claim 16 in which the non-return valve is located in the flow circuit of the second hydraulic circuit downstream of the connection of the pilot port of the pilot operated main valve to the flow circuit in the direction of flow of hydraulic fluid towards the at least one tensioning ram.

18. A belt baler as claimed in any of Claims 13 to 17 in which the return circuit comprises a pressure limiting valve for preventing the pressure of the hydraulic fluid in the at least one tensioning ram exceeding a hydraulic density pressure for forming a bale in the bale chamber to a corresponding bale density.

19. A belt baler as claimed in Claim 18 in which the pressure limiting valve is operable in an open state for accommodating hydraulic fluid therethrough returning from the at least one tensioning ram.

20. A belt baler as claimed in Claim 18 or 19 in which the hydraulic density pressure is selectable.

21. A belt baler as claimed in any of Claims 18 to 20 in which the pressure limiting valve comprises a solenoid operated valve.

22. A belt baler as claimed in any of Claims 18 to 21 in which the pressure limiting valve comprises a negative normally closed proportional pressure release valve.

23. A belt baler as claimed in any preceding claim in which the secondary valve comprises a solenoid operated valve.

24. A belt baler as claimed in any preceding claim in which the secondary valve is operable under the control of a signal processor in response to the signal produced by the detecting means.

25. A belt baler as claimed in Claim 24 in which the signal processor is programmed to control the operation of the secondary valve in response to the signal indicative of completion of circumferential wrapping of a bale in the bale chamber.

26. A belt baler as claimed in Claim 24 or 25 in which the signal processor is programmed to read the signal from the detecting means or to read the signal indicative of completion of circumferential wrapping of a bale in the bale chamber.

27. A belt baler as claimed in any of Claims 24 to 26 in which the signal processor is programmed to operate the pressure limiting valve into the open state in response to the signal indicative of completion of circumferential wrapping of the bale in the bale chamber.

28. A belt baler as claimed in any of Claims 24 to 27 in which the signal processor is responsive to a signal indicative of the hydraulic density pressure at which the pressure limiting valve is to limit the pressure of the pressurised hydraulic fluid in the at least one tensioning ram for operating the pressure limiting valve to prevent the pressure of the hydraulic fluid in the at least one tensioning ram exceeding the hydraulic density pressure.

29. A belt baler as claimed in any preceding claim in which the first and second hydraulic circuits are adapted for connecting to the pressurised hydraulic fluid source through a main spool valve, the main spool valve being operable in a first state for connecting the first hydraulic circuit to a high pressure side of the pressurised hydraulic fluid source and the second hydraulic circuit to a low pressure side of the pressurised hydraulic fluid source, and in a second state with the first hydraulic circuit connected to the low pressure side of the pressurised hydraulic fluid source and the second hydraulic circuit connected to the high pressure side of the pressurised hydraulic fluid source.

30. A belt baler as claimed in Claim 29 in which in the first state of the main spool valve, the flow circuit of the second hydraulic circuit is connected to the low pressure side of the pressurised hydraulic fluid source.

31. A belt baler as claimed in Claim 29 or 30 in which in the second state of main spool valve, the flow circuit of the second hydraulic circuit is connected to the high pressure side of the pressurised hydraulic fluid source.

32. A belt baler as claimed in any of Claims 29 to 31 in which the main spool valve is operable in a third state with the first and second hydraulic circuits isolated from the pressurised hydraulic fluid source.

33. A belt baler as claimed in any of Claims 29 to 32 in which the return circuit of the second hydraulic circuit is connected directly to the low pressure side of the pressurised hydraulic fluid source.

34. A belt baler as claimed in any of Claims 29 to 33 in which the belt baler is adapted for towing by a tractor, and the pressurised hydraulic fluid source is derived from the pressurised hydraulic system of the tractor.

35. A belt baler as claimed in any of Claims 29 to 34 in which the main spool valve is located in the tractor and is configured for operation by a driver of the tractor.

36. A belt baler as claimed in any of Claims 29 to 34 in which the main spool valve is located in the belt baler, and is operable under the control of the signal processor.

37. A belt baler as claimed in any preceding claim in which the diameter to which the bale is formed in the bale chamber is selectable.

38. A belt baler as claimed in any preceding claim in which the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state to accommodate a bale from the bale chamber.

39. A belt baler as claimed in Claim 38 in which the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state in response to the selected diameter of the bale entered into the signal processor.

40. A belt baler as claimed in any preceding claim in which a first monitoring means is provided for monitoring the position of the at least one tensioning roller and for producing a signal indicative of the diameter of a bale in the bale chamber, the signal processor being responsive to the signal from the first monitoring means for determining completion of the formation of the bale in the bale chamber and for operating the bale wrapping means to commence circumferential wrapping of the bale in the bale chamber.

41. A belt baler as claimed in any of Claims 38 to 40 in which the signal processor is programmed to determine from the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber, the minimum displacement of the moveable part between the bale forming state and the bale discharge state thereof for accommodating discharge of a bale from the bale chamber.

42. A belt baler as claimed in Claim 41 in which the signal processor is programmed to determine the minimum displacement of the moveable part from the bale forming state to the bale discharge state by computing the minimum displacement of the moveable part between the bale forming state and the baledischarge state as a function of the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber.

43. A belt baler as claimed in Claim 41 or 42 in which the signal processor is programmed to determine the minimum displacement of the moveable part between the bale forming state and the bale discharge state from a look-up table stored in an electronic memory of the signal processor or accessible to the signal processor, the look-up table comprising values of the signal produced by the first monitoring means indicative of the diameter of the bale in the bale chamber cross-referenced with the corresponding values of the minimum displacement of the moveable part between the bale forming state and the bale discharge state.

44. A belt baler as claimed in any of Claims 38 to 43 in which a second monitoring means is provided for monitoring the displacement of the movable part from the bale forming state and for producing a signal indicative of the displacement of the movable part from the bale forming state.

45. A belt baler as claimed in Claim 44 in which the signal processor is responsive to the signal produced by the second monitoring means being indicative of the moveable part being displaced from the bale forming state to the bale discharge state through the determined minimum angular displacement to operate the main spool valve or an isolating valve controlling supply of pressurised hydraulic fluid to the at least one main ram to terminate supply of pressurised hydraulic fluid to the at least one main ram.

46. A belt baler as claimed in any preceding claim in which the moveable part is pivotally coupled to the fixed part about a main pivot axis, and is pivotal about the main pivot axis between the bale forming state and the bale discharge state.

47. A belt baler as claimed in any preceding claim in which the at least one tensioning roller is carried on a pivotally mounted tensioning arm pivotal about a secondary pivot axis extending parallel with the main pivot axis or coinciding with the main pivot axis, and the at least one tensioning ram is cooperable with the tensioning arm for pivoting the tensioning arm about the secondary pivot axis for tensioning the at least one belt.

48. A belt baler as claimed in Claim 47 in which the first monitoring means is configured to monitor angular displacement of the tensioning arm about the secondary pivot axis.

49. A belt baler as claimed in Claim 47 or 48 in which the first monitoring means comprises a first angle sensor. .

50. A belt baler as claimed in any of Claims 46 to 49 in which the second monitoring means is configured to monitor angular displacement of the movable part about the main pivot axis from the bale forming state.

51. A belt baler as claimed in any of Claims 46 to 50 in which the second monitoring means comprises a second angle sensor.

52. A belt baler as claimed in any preceding claim in which the signal processor is responsive to completion of circumferential wrapping of the bale in the bale chamber for operating the moveable part from the bale forming state to the bale discharge state for discharging a bale from the bale chamber.

53. A belt baler as claimed in any preceding claim in which a pressure sensor is provided for monitoring the pressure of the hydraulic fluid in the at least one tensioning ram and for producing a signal indicative of the pressure of the hydraulic fluid in the at least one tensioning rams.

54. A belt baler as claimed in any preceding claim in which the predefined trip pressure at which the main valve operates from the closed state to the open state is not less than 30 bar.

55. A belt baler as claimed in any preceding claim in which the predefined trip pressure at which the main valve operates from the closed state to the open state is not less than 50 bar.

56. A belt baler as claimed in any preceding claim in which the predefined trip pressure lies in the range of 30 bar to 70 bar.

57. A belt baler as claimed in any preceding claim in which the predefined trip pressure is approximately 50 bar.

58. A belt baler as claimed in any preceding claim in which the at least one main ram comprises a single acting ram.

59. A belt baler as claimed in any preceding claim in which the at least one tensioning ram comprises a single acting ram.

60. A method for minimising the time to operate a moveable part of a belt baler from a bale discharge state to a bale forming state, the belt baler comprising a fixed part and the moveable part coupled to the fixed part and moveable relative to the fixed part from the bale forming state to the bale discharge state, at least one rotatably mounted tensioning roller mounted on one of the fixed part or the moveable part, at least one belt carried on the at least one tensioning roller to define a variable volume bale chamber and to rotate, press and form material therein into a round bale, at least one main ram operably coupled between the fixed part and the moveable part and operable from a retracted state to an extended state for urging the moveable part from the bale forming state to the bale discharge state, at least one tensioning ram cooperating with the at least one tensioning roller for urging the at least one tensioning roller to tension the at least one belt, a first hydraulic circuit adapted for connecting to a pressurised hydraulic fluid source for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one main ram, a second hydraulic circuit adapted for connecting to the pressurised hydraulic fluid source for applying pressurised hydraulic fluid from the pressurised hydraulic fluid source to the at least one tensioning ram, a main valve located in the first hydraulic circuit and being operable from a closed state for maintaining the at least one main ram in the extended state with the moveable part in the bale discharge state to an open state communicating the at least one main ram with the first hydraulic circuit to accommodate return of hydraulic fluid from the at least one main ram for accommodating return of the at least one main ram from the extended state to the retracted state in response to the pressure in the second hydraulic circuit exceeding a predefined trip pressure, the method comprising applying pressurised hydraulic fluid at a pressure not less than the predefined trip pressure to the second hydraulic circuit with the at least one tensioning ram isolated from the second hydraulic circuit, and maintaining the at least one tensioning ram isolated from the second hydraulic circuit until the at least one main ram has returned to the retracted state or the moveable part has returned to the bale forming state.

61. A method as claimed in Claim 60 in which the at least one tensioning ram is isolated from the second hydraulic circuit by a secondary valve located in the second hydraulic circuit, the secondary valve being operable from a closed state preventing flow of pressurised hydraulic fluid to the at least one tensioning ram into an open state communicating the at least one tensioning ram with the secondhydraulic circuit in response to a signal indicative of the at least one main ram having returned to the retracted state from the extended state or the moveable part having returned to the bale forming state from the bale discharge state.

62. A method as claimed in Claim 60 or 61 in which the secondary valve is operable from the open state to the closed state in response to one of the commencement of operation of the at least one tensioning ram from the retracted state to the extended state, the at least one tensioning ram being in the extended state, the commencement of movement of the movable part from the bale forming state to the bale discharge state, the movable part being in the bale discharge state, or completion of circumferential wrapping of a bale in the bale chamber.

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