GB2433551A

GB2433551A - Fluid circuit for remote consumer unit

Info

Publication number: GB2433551A
Application number: GB0526379A
Authority: GB
Inventors: Benjamin John Hanks; Elie Abi-Karam; Nathan John Lucas; James Edward Humphrey
Original assignee: Caterpillar SARL
Current assignee: Caterpillar SARL
Priority date: 2005-12-24
Filing date: 2005-12-24
Publication date: 2007-06-27
Anticipated expiration: 2025-12-24
Also published as: GB0526379D0; GB2433551B

Abstract

A fluid circuit for a work machine such as a backhoe comprises a load sensing displacement controller 52 operating a variable displacement pump 51 which supplies first and second circuits 61, 63, each having respective proportional or discreet direction control valves 62, 70 and cylinders 32, 26 for e.g. raising and lowering front and rear working arms. The control valves are operated by actuators 80, 82 and 84, 86 under control of respective operating arrangements 110, 112 and receive pilot pressure at less than system pressure via a pilot valve 92, accumulator 100 and a solenoid controlled shut off valve 96 under supervision of another operating arrangement 106. A third e.g. steering circuit 134 is also supplied by the pump, as is an auxiliary circuit via a selection valve through which fluid may selectively flow through connectors 36, 38 to a remote consumer 44 e.g. a manually operated power tool. When the selector valve is open its controller 143 commands that the shut off valve 96 to immobilise the first and second circuits for safety.

Description

Description

Fluid circuit for remote consumer unit

Technical Field

[01] The disclosure generally relates to work machines capable of powering remote tools and more particularly to work machines having integrated safety systems and capable of powering remote fluid-powered tools.

Background

[02] Work machines such as for example a backhoe loader are often used in construction where a variety of duties are to be performed. A wide range of machines and tools is often needed to be able to cope with all the duties requiring a multitude of power sources. Solutions exist wherein work machines have been adapted to be able to supply compressed air to power tools but these machines require significantly more components and adaptations to the drive line to be able to drive the compressors, store the compressed fluids and provide sufficient levels of power to the tools. Often this is to the detriment of other machine functions as there is not enough space on board to allow coexistence of multiple options. Other solutions have included adaptations of hydraulic circuits so as to supply power to remote tools, hut these have drawbacks that the machine remains fully operable during the operation of the remote tool which may lead to high levels of risk exposure for the operator of the remote tool.

[03] There is a need for a safe and cost effective solution for providing sufficient levels of power to remote tools without reducing the customer's options for machine configuration.

[04] The current disclosure is directed at overcoming one or more of the aforementioned concerns. [05]

Summary of the Invention

[06] In accordance with an embodiment of the current disclosure there is disclosed a fluid arrangement for a work machine. The fluid arrangement includes a fluid supply and a first circuit fluidly connected with the fluid supply for supplying fluid to at least one system of said work machine. It further includes an auxiliary circuit fluidly connected with the fluid supply for supplying fluid to a remote consumer and a control arrangement for selectively activating the auxiliary circuit and simultaneously deactivating the first circuit.

[07] Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

[08] Fig. I is a schematic representation of an embodiment of a work machine and a remote consumer unit powered by the work machine in accordance with the

current disclosure.

[09] Fig. 2 is a fluid schematic suitable for the work machine and remote consumer arrangement of Fig. 1.

Detailed Description

[10] Fig. 1 shows a work machine 10 which in this particular embodiment is a machine known as a backhoe loader, but may be any other suitable work machine. The work machine 10 is driven by an internal combustion engine (not shown) and is steerable via a steering system including a steering wheel 12 which may affect the orientation of the front wheels 14 and sometimes, depending on the type of machinery also the rear wheels 16. The work machine 10 may further have a variety of utilities such as a front mounted work arm 18, a rear mounted work arm 20 such as back hoe 20 (shown partially) and stabilizers 22. It is to be understood that in this context the designations front or rear may include being adjacent to a front or a rear end of the work machine 10. A system of a work machine in the context of this specification is any mechanical tool or arrangement, for example the aforementioned utilities or steering system, together with its associated circuit or part of a circuit.

[11] The work machine 10 may further have an operator platform 11 in which are located controls such as for example a control panel 15 or a set of levers 17 for operating a variety of functions. Such functions may include lifting the front mounted work arm 18, tilting an attached work tool 24 such as a bucket, operating the rear mounted work arm 20 such as raising, lowering, turning the rear mounted work arm 20 relative to the rest of the work machine 10, and where a side shift frame is included (not shown) the rear mounted work arm 20 may be shifted from the left hand side of the work machine 10 to the right hand side of the work machine 10 and vice versa or be placed in an intermediate position if so preferred. Most or all of those functions as described above are performed by controlling cylinders such as a rear mounted work arm lift cylinder 26, a rear mounted work arm turning cylinder 28, a stabilizer arm cylinder 30 and a front mounted work arm cylinder 32.

[12] The work machine 10 may further be provided with an auxiliary arrangement 34 for providing a fluid such as hydraulic oil to a remote consumer 44. Machines such as back hoe loaders are often used on general construction sites where there is a need to use a wide variety of tools and equipment that require some sort of power supply. In this embodiment the auxiliary arrangement 34 is represented by a set of couplings 36 and 38 for coupling a pair of fluid carriers 40 and 42 such as hydraulic hoses. The fluid carrier 40 may be for supplying the remote consumer 44 with pressurized fluid whilst the fluid carrier 42 may carry the fluid from the remote consumer 44 back to the work machine 10. The remote consumer 44 may be a compatible work tool such as manually operated power tools for example fluid driven hammers or fluid driven cutters, etc. [13] Turning now to Fig. 2, there is shown a simplified fluid diagram corresponding to an embodiment of this disclosure. A fluid supply 50 which in this example may be represented by a variable displacement pump 51 and a load sensing displacement controller 52 draws a fluid such as hydraulic oil from reservoir 56 and pumps it into line 54. The variable displacement pump may be driven directly or indirectly by an internal combustion engine (not shown). From line 54 at least a portion of the pressurized fluid may flow through lines 58 and towards a first circuit 61 where it may arrive at the selection valve 62. In this example the selection valve 62 may be regarded as being a proportional valve with an infinite number of valve positions but it may also be a valve with a discrete number of available positions such as for example 3. Depending on the selected position of the selection valve 62, the pressurized fluid may flow to either the full bore side 64 or the annulus side 66 of the cylinder 32. The cylinder 32 is part of the first circuit 61, but it maybe part of any circuit. In this example the cylinder 32 is the cylinder for raising and lowering the front mounted work arm 18.

[14] From line 54 at least a portion of the pressurized fluid may flow through lines 58 and 68 towards a second circuit 63 where it may arrive at the selection valve 70. In this example the selection valve 70 may be regarded as being a proportional valve with an infinite number of valve positions but it may also be a valve with a discrete number of available positions such as for example 3.

Depending on the selected position of the selection valve 70, the pressurized fluid may flow to either the full bore side 72 or the annulus side 74 of the cylinder 26.

The cylinder 26 is part of the second circuit 63, but it may be part of any circuit.

in this example the cylinder 26 is the cylinder for raising and lowering the rear mounted work arm 20. It is to be understood that the first and second circuits 61 and 63 may of course be part of the same circuit if preferred.

[15] Both the first and second circuits 61 and 63 may have load sensing means as part of a load sensing arrangement and exemplary load sensing means are shown in the form of load sensing signal lines 76 and 78. The load sensing signal lines 76 and 78 carry a load sensing signal to the load sensing displacement controller 52 to adjust the displacement of the variable displacement pump 51 when required. The selection valves 62 and 70 have actuators 80, 82, 84 and 86 for controlling the valve which will be discussed in more detail later.

[16] From line 54 at least a portion of the fluid may also flow via line 90 to a filter 97 and a pilot valve 92. The pilot valve 92 generates a pilot pressure which is lower than the typical maximum system pressure. For example the maximum system pressure may be in the order of 250 bar whilst the pressure downstream of the pilot valve may be no more than 20 bar. The minimum pressure generated by the fluid supply 50 may be set such that that pressure is always higher than the pressure provided by the pilot valve 92 to ensure the pilot valve 92 is always capable of providing the required pilot pressure during normal operation. From the pilot valve 92 the pilot fluid may flow via a line 95, a shut-off valve 96 and a line 98 to the actuators 80, 82, 84 and 86. An accumulator 100 may be included in the circuit to act as a temporary source of pressurised fluid when no fluid passes through the pilot valve 92. A check valve 102 may also be fitted in the line to prevent any reverse flow between shut off valve 96 and the pilot valve 92 [17] The shut off valve 96 has a solenoid 104 which may be controlled by a operating arrangement 106 in order direct fluid from to the line 95 to either the line 98 or the reservoir line 108. The shut off valve 96 may either be normally open or normally closed and the operating arrangement 106 may be omitted if preferred and the solenoid 104 may for example be controlled directly by the operating arrangements 143 and 172.

[18] The pilot flow from the line 98 may flow to the actuators 80, 82, 84 and 86. The actuators 80 and 82 may be controlled by an operating arrangement 110 and the actuators 84 and 86 may in a similar fashion be controlled by an operating arrangement 112. As the selection valves 62 and 70 may operate in a similar fashion only the operation of the selection valve 62 will be explained in more detail, but it is to be understood that the principle may apply to both the selection valves 62 and 70. An operator (not shown) may wish to raise the work arm 18. The operator therefore generates a signal via an operating arrangement which may be an input device such as a joystick, a switch or a lever which may be part of the set of levers 17. The operating arrangement 110 sends a signal via the signal line 114 to the actuator 80. In response to that signal the actuator 80 will direct the pilot pressure standing at the actuator 80 towards the valve 62, enabling the valve 62 to shift over to a position such that the line 60 is connected with the full bore side 64 of the cylinder 32. To return the selection valve 62 to its neutral position the operating arrangement may send a signal to the opposing actuator 82 and end the signal to the actuator 80 or alternatively the valve 62 may be provided with neutralizing springs (not shown) that neutralize the valve when no signal is provided to either of the actuators 80 and 82. As noted above, the selection valve 70 may be operated in a similar fashion albeit via an operating arrangement 112, the signal lines 118 and 120 and the actuators 84 and 86.

[19] It is to be understood that the diagram as shown in Fig. 2 is simplified for clarity purposes and that for example lines internal of the selection valves 62 and and the actuators 80-86 may therefore have been omitted. In a similar fashion, the system may include many more selection valves and cylinders such as the selection valve 62 and 70 and the cylinders 26 and 32.

[20] From the line 54, at least a portion of the pressurized fluid may flow via the line 130 and 132 to a third circuit 134 which may be a steering circuit. The third circuit 134 may be a steering circuit be of a type known in the art and will not be discussed in further detail. From the line 130, at least a portion of the pressurized fluid may flow via a line 136 towards a selection valve 138. The selection valve 138 may be of the type that is biased in a closed position via a spring 140 and may be opened via a solenoid 142 which is controlled by an operating arrangement 143. When the selection valve 138 is in the open position fluid may flow from the line 136 to the line 144 and from there into the line 146 towards the coupler 36. The coupler 36 may be a quick release coupler for quickly connecting and disconnecting a fluid carrier 40. Once connected, pressurized fluid may flow up to the remote consumer 44 to power the remote consumer 44. Once the fluid has passed through the remote consumer 44, the fluid may return to the reservoir via the fluid carrier 42 and via the coupler 38 which may he of the quick connect and disconnect type. If preferred, the quick couplers 36 and 38 may be provided with a safety arrangement such that the fluid carrier 40 can only connect with the coupler 36 and that the fluid carrier 42 can only connect with the coupler 38. This may for example be achieved by providing the fluid carrier 40 with the male portion of the connection 36 whilst its corresponding female portion of the connection 36 is fixed on the work machine 10. In contrary, the fluid carrier 42 should then be provided with the female portion of the connection 38, whilst the male portion of the connection 38 is fixed on the work machine 10.

[21] The line 150 may be connected to a valve such as pressure regulating valve 148 for being able to control the maximum pressure in the line 150. The pressure regulating valve 148 may be adjustable so as to adjust the working pressure to the demands of the work tool 44. The flow flowing towards the work tool 44 may be regulated by a valve such as the adjustable flow regulating valve 152. The pressure regulating valve 148, the flow regulating valve 152 and the couplers 36 and 38 form part of a circuit 160 which may for ease of reference be referred to as the auxiliary circuit. The auxiliary circuit may include a load sensing means 153 such as a load sensing signal line.

[22] From the line 144 fluid may flow through the line 162 to the valve 164.

The valve 164 may be any valve such as a directional valve or a proportional valve. In this embodiment the valve 164 is a solenoid operated 2-way, 3-position directional valve for selectively directing fluid to the rear mounted work arm side shift cylinders 166. The solenoids 168 and 170 are controlled by an operating arrangement 172.

[23] The operating arrangements 143 and 170 may be of any suitable type, for example, in one embodiment the operating arrangement 143 is an unbiased 2 position switch that stays in a first position unless the operator changes the switch over into the second position. In that same embodiment the operating arrangement 172 may be a biased lever as part of the set of levers 17 and the biased lever may naturally assume a neutral position unless engaged by the operator.

[24] The operating arrangements 106, 110, 112, 143 and 172 may all be linked electronically, or only some may be linked, or at least some may be at least partially integrated into one operating arrangement such as a single electronic control unit with a variety of input devices such as switches and levers attached electronically.

[25] In the embodiment as shown in Fig 2. the operating arrangements 106, 143 and 172 are linked. The operating arrangement 143 includes in that particular embodiment an actuator 13, e.g. an on-off switch, fitted remote from the operator platform 11 as shown in Fig. 1. The actuator 13 is fitted near the couplings 36 and 38 to enable a quick connect and activation and deactivation of the auxiliary circuit 160. The operating arrangement 143 may further include a safety switch (not shown) to quickly deactivate the auxiliary circuit or even the whole work machine 10 in case of an emergency. In that same embodiment the operating arrangement 172 may be a one of the levers 17 on the operator platform 11 and it may be an electronic lever that controls an electronic signal to the solenoids 168 and 170. In this embodiment the operating arrangement 143 controls both the selection valve 138 and the shut off valve 96. The operating arrangement 143 may be controlling the solenoids 142 and 104 such that selecting to open the valve 138 automatically triggers the shut off valve 96 to shut off the connection between the lines 95 and 98 so that no pilot pressure is available for the actuators 80, 82, 84 and 86. At the same time it may disable all electronic signals from the operating arrangement 172 so the valve 164 remains in its neutral position and the side shift cylinders 166 can not be operated. In this same embodiment operation of the operating arrangement 172 may automatically open up the selection valve 138, either directly or via the operating arrangement 143 if preferred, and close the shut off valve 96 such that the lines 95 and 98 are not connected. [26]

Industrial Applicability

[27] During operation an operator (not shown) may operate the work machine from the operator platform 11 which allows him to operate, inter alia, the steering wheel 12 to control the third circuit 134, the control panel 15 and the set of levers 17 to control at least the first and second circuits 61 and 63, which are connected to respective systems of the work machine. When the operator has reached a location where there is a need for the use of a remote consumer 44, such as for example a fluid driven hammer, the operator may leave the work platform I I with the internal combustion engine still running and connect the fluid carriers 40 and 42 to both the remote consumer 44 and the couplings 36 and 38. Before or after the remote consumer 44 is connected with the work machine, the operator may engage the operating arrangement 143 which in this embodiment includes the switch 13. The switch 13 is conveniently located close to the couplings 36 and 38 and therefore remote from the operator platform 11.

This enables the operator to quickly connect the remote consumer 44 and activate the auxiliary circuit 160 remote from the work platform 11. By activating the auxiliary circuit 160 fluid from the fluid supply 50 may travel via the lines 54, 130, 136, 144 and 150 to the coupling 36 from where it may travel to the coupling 36 and if the connection has been made through to the remote consumer 44. The operator may adapt the flow and pressure characteristics of the auxiliary circuit 160 to the requirement of the remote consumer 44 by adjusting the pressure regulating valve 148 and the flow regulating valve 152. The demands of the remote consumer 44 may be relayed to the load sensing displacement controller 52 via the load sensing means 153. The load sensing displacement controller 52 may adjust the variable displacement pump 51 to vary the supply in accordance with the needs of the remote consumer 44. The capability of the fluid supply 50 to increase flow independently from the engine speed is beneficial for the operator as no particular engine speed needs to be selected by the operator before the operator leaves the operator platform 11. By having activated the auxiliary circuit 160 the operating arrangement 143 has either directly or indirectly operated the shut off valve 96 by sending a signal to assume such a position that the pilot flow as generated by the fluid supply 50 in combination with the pilot valve 92 is being directed into the line 108 which carries the fluid back to the reservoir 56. Therefore there is no pilot flow available for the actuators 80, 82, 84 and 86 to actuate either of the selection valves 62 or 70 and therefore the first and second circuits 61 and 63 are deactivated. Whilst a first operator is operating the remote consumer 44, a second operator may still be able to move the work machine 10 forwards or backwards and thereby steer the work machine 10 using the third circuit 134. However, if preferred actuation of the operating arrangement 143 may also block the third circuit 134 and for example the driveline of the work machine such that the machine is completely immobilized.

[28] With the auxiliary circuit activated, fluid is also supplied to the directional valve 164. However, the operating arrangement 143 is linked to the operating arrangement 172 such that no signal can be provided to either of the solenoids 168 and 170, thereby immobilizing the side shift cylinders 166.

[29] In a scenario where the selection valve 138 has not been actuated but a first operator actuates the operating arrangement 172 the following sequence of events may occur. By actuating operating arrangement 172, the selection valve 138 and the directional valve 164 will be operated such that the side shifting cylinders 166 slide the rear mounted work arm 20 to one side of the work machine 10. It may be preferred to immobilize all other functions related to either the front mounted work arm 18 or the rear mounted work arm 20 to avoid abuse of the work machine 10. Hence actuating the operating arrangement 172 may be linked with placing the shut off valve 96 in a position such that no pilot oil is available for the actuators 80, 82, 84 or 86. However, as can be seen from the diagram in Fig. 2, by actuating operating arrangement 172 fluid will also be available to the auxiliary circuit 160. Therefore if a second operator is preparing to use the remote consumer 44 the second operator should actuate the operating arrangement 143 in order to disable the side shift cylinders 166 via the link between the operating arrangement 143 and the operating arrangement 172 in order to stay safe.

[30] It is to be understood that although the function of the selection valves 62 and 70 may be hindered by interruption of the pilot fluid supply to those valves, in a different embodiment it may be preferred to block the supply of fluid from the pump to the selection valves 62 and 70. In yet another embodiment where the selection valves 62 and 70 are solenoid operated the selection valves 62 and 70 may be immobilized by the interrupting the power supply to those solenoid valves.

[31] Although the preferred embodiments of this invention have been described herein, improvements and modifications may be incorporated without from the departing scope of the following claims. 1'-

Claims

1 CLAIMS 3 1. A fluid arrangement for a work machine, said fluid 4

arrangement comprising: a fluid supply, 6 a first circuit fluidly connected with said fluid supply for supplying 7 fluid to at least one system of said work machine, 8 an auxiliary circuit fluidly connected with said fluid supply for 9 supplying fluid to a remote consumer, and a control arrangement for selectively activating said auxiliary circuit 1 1 and simultaneously deactivating said first circuit.

13
2. A fluid arrangement according to claim 1, wherein said first 14 circuit is operated by a pilot flow and said control arrangement controls said pilot flow to activate and deactivate said first circuit.

17
3. A fluid arrangement according to any of the preceding claims 18 wherein said fluid supply is a load sensing variable displacement pump and 1 9 said auxiliary circuit has signal means for providing said load sensing variable displacement pump with a load sensing signal.

22
4. A fluid arrangement according to any of the preceding claims 23 wherein said remote consumer is a manually operated power tool.

5. A fluid arrangement according to any of the preceding claims 2 6 wherein said at least one system includes a work arm arrangement.

28 6. A fluid arrangement according to any of claims 1 to 4 wherein 2 9 said at least one system includes a first work arm arrangement adjacent to a front end of said machine and a second work arm arrangement adjacent to a 31 rear end of said work machine.

1 7. A fluid arrangement according to any of the preceding claims 2 wherein said auxiliary circuit includes a quick release coupler for connecting 3 said remote consumer to said auxiliary circuit.

8. A fluid arrangement according to any of the preceding 6 claims wherein said work machine has an operator platform having a plurality 7 of controls for controlling at least one function of said work machine and said 8 work machine has an actuator remote from said operator platform for 9 activating said auxiliary circuit.

11 9. A fluid arrangement according to any of the preceding claims 12 wherein said work machine has an operator platform having a plurality of 13 controls for controlling at least one function of said work machine and said 14 work machine has an actuator remote from said operator platform for deactivating said auxiliary circuit.

17 10. A fluid arrangement according to any of the preceding claims 18 wherein said fluid arrangement further includes a steering circuit for steering 19 said work machine, wherein said control arrangement operates such that said steering circuit remains active whilst said auxiliary system is active.

22 Il. A fluid arrangement according to any of claims 1 to 9 wherein 23 said fluid arrangement further includes a steering circuit for steering said 24 work machine, wherein said control arrangement operates such that said steering circuit is deactivated whilst said auxiliary system is active.

27 12. A fluid arrangement according to claim 6, wherein said fluid 28 arrangement includes a solenoid operated selection valve for activating and 2 9 deactivating said auxiliary circuit and said fluid arrangement further includes a side shift circuit for side shifting said second work arm arrangement, said 31 side shift circuit including a directional valve and a cylinder downstream of 32 said directional valve, said directional valve being fluidly connected with said 1 solenoid operated selection valve such that said directional valve receives 2 fluid whenever said auxiliary circuit receives fluid.

4 13. A fluid arrangement according to claim 12, wherein said operator platform includes an actuator for operating said directional valve.