Controlled actuation in a working machine

Abstract

A hydraulic circuit for actuating a hydraulic ram 110, having a manual spool valve 114, which spool is manually operable by a hand lever 112 directing hydraulic fluid to either the rod 400 or head sid

Description

TECHNICAL FIELD

[0001] The present subject matter relates to aspects of controlled actuation in a working machine. BACKGROUND

[0002] Generally, working machines, such as backhoe loaders, slew excavators, telescopic handlers, forklifts, and skid-steer loaders, may be employed in construction industry or otherwise for moving loads. The working machine may have a working arm, also referred to as a boom, movably mounted to a body of the working machine. A working implement, such as a bucket or a grabber, is attached to the end of the arm. The provision of the working arm and the working implement enables the working machine to perform a variety of tasks. In order to enable movement of the working arm and / or the working implement, the working machines have the provision of an actuation system operable using hydraulic power, i.e., the actuation system uses pressurized fluids in a closed hydraulic circuit to actuate the working arm. SUMMARY OF THE INVENTION

[0003] According to a first aspect of the present teachings, there is provided a controlled actuation system for a working machine. The controlled actuation system comprises: a ram assembly having a fluid-actuated plunger movably disposed therein. The ram assembly may be divided into a head side and a rod side by the fluid-actuated plunger. The fluid-actuated plunger may have a rod connected to a load for actuating the load. A mechanical valve may be hydraulically coupled to the ram assembly, the mechanical valve may have a spool movable therein to control flow of a hydraulic fluid through the mechanical valve, in which movement of the spool may be controllable by a hand lever. A sensor may monitor a position of the spool in the mechanical valve. A control valve may be hydraulically coupled to the fluid-actuated plunger. The control valve may be controllable to control flow of the hydraulic fluid to one of the head side and the rod side to regulate the movement thereof. A primary pump may be hydraulically coupled to the mechanical valve, the control valve and the ram assembly to form a hydraulic circuit. The primary pump may be configured to provide a flow of the hydraulic fluid in the hydraulic circuit of the controlled actuation system. A control unit may be operably coupled to the sensor to receive at least a position signal corresponding to the position of the spool of the mechanical valve. The control unit may be configured to control at least one of the primary pump and the control valve, based on the position signal, to regulate the flow of the hydraulic fluid to at least one of the head side and the rod side of the ram assembly for regulating the movement of the fluid-actuated plunger.

[0004] The controlled actuation system for a working machine of the present subject matter includes a mechanical-hydraulic system for operating a load, by enabling movement of the working machine, in response to an input from an operator. The controlled actuation system is a mechanical-hydraulic system with mechanical components, as illustrated above, such as the hand lever, the mechanical valve, the spool, the control valve, the sensor, and the like, that are mechanical components in the system in a hydraulic circuit thereby, making the entire system less complex and less expensive. Correspondingly, the cost of maintenance and upkeep of the components and thereby, the controlled actuation system of the present subject matter is less, since the components are less expensive and may incur minimal cost.

[0005] Each component of the controlled actuation system of the present subject matter works in a coordinated manner, even if each component operates differently based on respective operations, thereby providing the required output without any inconsistencies. Also, the present subject matter provides the flexibility of easily incorporating different modalities of operations in the controlled actuation system.

[0006] The control unit of the controlled actuation system may be configured to perform a lifting motion of the ram assembly, in response to determining that the spool is in one of a full lift position and an intermediate lift position, by causing supply of the hydraulic fluid, through the mechanical valve, to the head side of the ram assembly for the ram assembly to exhibit the lifting motion.

[0007] The control unit of the controlled actuation system, in the intermediate lift position of the spool, may be configured to cause the primary pump to supply the hydraulic fluid at a first flow rate to the head side of the ram assembly. The first flow rate is determined based on the position of the spool.

[0008] Advantageously, the control unit may, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, may cause the ram assembly to exhibit lifting motion in a similar motion and to the position as requested and required by the operator. The ram assembly may be lifted at a speed required by the operator. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[0009] The control valve of the controlled actuation system may be a counterbalance valve.

[0010] The control unit of the controlled actuation system may be configured to perform a lowering motion of the ram assembly, in response to determining that the spool is in one of a full drop position and an intermediate drop position, by causing supply of the hydraulic fluid through the mechanical valve and the counterbalance valve, to the rod side of the ram assembly for the ram assembly to exhibit the lowering motion.

[0011] The control unit of the controlled actuation system may be configured to control the counter-balance valve to regulate the supply of the hydraulic fluid to the rod side of the ram assembly, in response to determining that the spool is in one of the full drop position and the intermediate drop position.

[0012] Advantageously, the control unit may, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, may cause the ram assembly to exhibit lowering motion in a similar motion and to the position as requested and required by the operator.

[0013] The electro-proportional control valve (EPCV) of the controlled actuation system may be hydraulically coupled to the counter-balance valve. The EPCV may be operably coupled to the control unit and may be controllable to hydraulically regulate an operation of the counter-balance valve.

[0014] The control unit of the controlled actuation system, in response to determining that the spool may be in one of the full drop position and the intermediate drop position, may be configured to send a control signal to the EPCV. In response to the control signal, the EPCV may send a pilot signal to the counterbalance valve for regulating an opening of the counter-balance valve. The control unit is to regulate an extent of the opening of the counter-balance valve.

[0015] The pilot signal may be in form of flow of the hydraulic fluid, and the control unit may be configured to cause flow of the hydraulic fluid to the EPCV to generate the pilot signal at the EPCV.

[0016] The controlled actuation system may comprise a secondary pump to provide hydraulic fluid to the EPCV. The secondary pump may be controllable by the control unit to provide the flow of the hydraulic fluid to the EPCV. The controlled actuation system may comprise a shuttle valve to control flow of the hydraulic fluid to the EPCV from at least one of the primary pump and the secondary pump. The shuttle valve may allow the flow of the hydraulic fluid to the EPCV having a higher pressure between the hydraulic fluid from the primary pump and the hydraulic fluid from the secondary pump.

[0017] The opening of the counter-balance valve may be a function of the position of the spool in the full drop position.

[0018] The opening of the counter-balance valve may be less than an opening of the spool in the full drop position.

[0019] The opening of the counter-balance valve may be a function of the position of the spool in the intermediate drop position.

[0020] The opening of the counter-balance valve may be less than an opening of the spool in the intermediate drop position.

[0021] Advantageously, the opening of the counter-balance valve being less than an opening of the spool may limit the maximum speed of movement of the ram assembly. In this manner, the components of the controlled actuation system may have a restricted maximum speed of the ram assembly, ensuring the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly.

[0022] The opening of the counter-balance valve may create a flow path between the head side and rod side of the ram assembly and may create a return flow path from the head side to a fluid reservoir.

[0023] The opening of the counter-balance valve, during execution of the lowering motion of the ram assembly, may cause excess hydraulic fluid from the head side of the ram assembly to be directed to a fluid reservoir through the counterbalance valve.

[0024] Advantageously, the return flow path from the head side to a fluid reservoir allows the excess hydraulic fluid from the head side of the ram assembly to split from the flow and may be allowed to flow to the fluid reservoir. Therefore, any pressure build up, back pressure or any resistance in fluid flow in the hydraulic connection may be avoided.

[0025] The control unit of the controlled actuation system may be configured to: establish, based on the position signal received from the sensor, a rate of change of position of the spool, and may control a speed of opening of the counter-balance valve as a function of the rate of change of position of the spool.

[0026] Advantageously, the control unit may control speed of movement of the ram assembly based on the change in position of the spool.

[0027] The control unit of the controlled actuation system may be configured to restrict the speed of opening of the counter-balance valve upon establishing that a rate of change in position of the spool has exceeded a pre-defined threshold rate of change of position.

[0028] Advantageously, the speed of movement of the ram assembly may be restricted to the pre-defined threshold rate of change of position. The control unit may restrict the speed of opening of the counter-balance valve upon establishing that the rate of change in position of the spool has exceeded a pre-defined threshold rate of change of position. As a result, the controlled actuation system may ensure the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly.

[0029] The counter-balance valve of the controlled actuation system may perform functions of a hose burst valve to stop the flow of hydraulic fluid in response to determining the condition of bursting of a hydraulic hose in the hydraulic circuit.

[0030] Advantageously, the counter-balance valve may perform the functions of the hose burst valve in addition to the functions illustrated above for the counterbalance valve. In this manner, the counter-balance valve may, along with the functions illustrated above, also control the speed of movement of the ram assembly and prevent sudden lowering of ram assembly in case of hydraulic hose bursting.

[0031] The valve of the controlled actuation system may be a hose burst valve. The hose burst valve is to stop the flow of hydraulic fluid in response to determining the condition of bursting of a hydraulic hose in the hydraulic circuit.

[0032] Advantageously, the control valve may control the speed of movement of the ram assembly and prevent sudden lowering of ram assembly in case of hydraulic hose bursting.

[0033] According to a second aspect of the present teachings, there is provided a control unit for a controlled actuation system of a working machine. The control unit being coupled to a sensor, a primary pump, and a control valve may regulate movement of a ram assembly of the controlled actuation system. The control unit may be configured to: determine, from the sensor, a position of a spool of a mechanical valve. The spool may be movable in the mechanical valve to control flow of a hydraulic fluid through the mechanical valve. The position of the spool may be controllable by a hand lever. The control unit may cause, in response to determining that the spool may be in lift position, the primary pump may supply the hydraulic fluid, through the mechanical valve, to a head side of the ram assembly for the ram assembly to exhibit a lifting motion; and cause, in response to determining that the spool may be in drop position, the primary pump may supply the hydraulic fluid through the mechanical valve and the control valve, to a rod side of the ram assembly for the ram assembly to exhibit a lowering motion. In the drop position of the spool, the control unit may be configured to control the control valve to regulate the supply of the hydraulic fluid to the rod side of the ram assembly, to assist the ram assembly in exhibiting the lowering motion.

[0034] The control unit of the controlled actuation system for a working machine of the present subject matter coordinates with each component of the controlled actuation system, such that each component of the controlled actuation system of the present subject matter work in a coordinated manner even if each component operate differently based on the respective operations. As a result, the required output is attained without any inconsistencies. Also, the present subject matter provides the flexibility of easily incorporating different modalities of operations.

[0035] The control unit may be configured to exhibit lifting motion in response to determining that the spool is in one of a full lift position and an intermediate lift position.

[0036] The control unit, in the intermediate lift position of the spool, may be configured to cause the primary pump to supply the hydraulic fluid at a first flow rate to the head side of the ram assembly. The first flow rate may be determined based on the position of the spool.

[0037] Advantageously, the control unit may, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, may cause the ram assembly to exhibit lifting motion in a similar motion and to the position as requested and required by the operator. In other words, the control unit may control the flow rate of the hydraulic fluid to the head side of the ram assembly, that may influence the speed at which the ram assembly may be lifted. As a result, the ram assembly may be lifted at a speed as required by the operator i.e., based on the rate of change of movement of the spool monitored by the sensor. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[0038] The control unit, in response to determining that the spool is in one of a full drop position and an intermediate drop position, may be configured to perform the lowering motion of the ram assembly.

[0039] The control unit may be configured to one of directly and indirectly send the control signal to the control valve, wherein the control valve may be one of a counter-balance valve and a hose burst valve.

[0040] Advantageously, the control unit may, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, may cause the ram assembly to exhibit lowering motion in a similar motion and to the position as requested and required by the operator. In other words, the control unit may control the flow rate of the hydraulic fluid to the rod side of the ram assembly via the counter-balance valve, that may influence the speed at which the ram assembly may be lowered. As a result, the ram assembly may be lowered at a speed as required by the operator i.e., based on the rate of change of movement of the spool monitored by the sensor. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[0041] Advantageously, the control valve may control the speed of movement of the ram assembly and prevent sudden lowering of ram assembly in case of hydraulic hose bursting.

[0042] The control unit, in response to determining that the spool is in one of the full drop position and the intermediate drop position, may be configured to transmit a control signal to an electro-proportional control valve (EPCV). The EPCV in response to the control signal may send a pilot signal to a counter-balance valve for regulating an opening of the counter-balance valve. By regulating the control unit may control an extent of the opening of the counter-balance valve.

[0043] The control unit may be configured to: establish, based on a position signal received from the sensor, a rate of change of position of the spool; and control speed of opening of the counter-balance valve as a function of the rate of change of position of the spool.

[0044] The control unit may be configured to control speed of movement of the ram assembly as a function of position of the spool.

[0045] Advantageously, control unit ensures that the opening of the counterbalance valve is less than an opening of the spool may limit the maximum speed of movement of the ram assembly. In this manner, the components of the controlled actuation system may have a restricted maximum speed of the ram assembly, ensuring the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly. [00461 The control unit may be configured to restrict a speed of opening of the counter-balance valve upon establishing, that a rate of change in position of the spool may have exceeded a pre-defined threshold rate of change of position.

[0047] Advantageously, the speed of movement of the ram assembly may be restricted to the pre-defined threshold rate of change of position by the control unit, upon establishing that the rate of change in position of the spool has exceeded a pre-defined threshold rate of change of position. As a result, the controlled actuation system may ensure the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly.

[0048] The control unit may be configured to one of directly and indirectly send the control signal to the counter-balance valve, in response to conditions of a hydraulic hose. The counter-balance valve may perform functions of a hose burst valve to stop the flow of hydraulic fluid in response to determining the condition of bursting of a hydraulic hose in the hydraulic circuit.

[0049] Advantageously, the counter-balance valve may perform the functions of the hose burst valve in addition to the functions illustrated above for the counterbalance valve. In this manner, the counter-balance valve may, along with the functions illustrated above, also control the speed of movement of the ram assembly and prevent sudden lowering of ram assembly in case of hydraulic hose bursting.

[0050] According to a third aspect of the present teachings, there is provided a method that may regulate movement of a ram assembly of a controlled actuation system. The controlled actuation system may comprise a sensor, a primary pump, and a control valve. The method may comprise: determining, from the sensor, a position of a spool of a mechanical valve. The spool may be movable in the mechanical valve to control flow of a hydraulic fluid through the mechanical valve. The position of the spool may be controllable by a hand lever. The method includes causing, in response to determining that the spool may be in a lift position, the primary pump may supply the hydraulic fluid, through the mechanical valve, to a head side of the ram assembly for the ram assembly to exhibit a lifting motion. The method further includes causing, in response to determining that the spool may be in a drop position, the primary pump may supply the hydraulic fluid through the mechanical valve and the control valve, to a rod side of the ram assembly for the ram assembly to exhibit a lowering motion. The causing comprises controlling the control valve to regulate the supply of the hydraulic fluid to the rod side of the ram assembly.

[0051] Advantageously, the above-mentioned features of regulating movement of a ram assembly of a controlled actuation system may ensure each component of the controlled actuation system operate in a co-ordinated manner, even if each component operate differently based on the respective operations. As a result, the required output is attained without any inconsistencies. Also, providing the flexibility of easily incorporating different modalities of operations.

[0052] The method step may include exhibiting the lifting motion of the ram assembly in response to determining that the spool is in one of a full lift position and an intermediate lift position.

[0053] Advantageously, through the above-mentioned features, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, the ram assembly may exhibit lifting motion in a similar motion and to the position as requested and required by the operator. In other words, the control unit may control the flow rate of the hydraulic fluid to the head side of the ram assembly, that may influence the speed at which the ram assembly may be lifted. As a result, the ram assembly may be lifted at a speed as required by the operator i.e., based on the rate of change of movement of the spool monitored by the sensor. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[0054] The method step may include exhibiting the lowering motion of the ram assembly in response to determining that the spool is in one of a full drop position and an intermediate drop position.

[0055] The method step of exhibiting the lowering motion may comprise supplying, the hydraulic fluid at a first flow rate to the head side of the ram assembly, in response to determining that position of the spool is in the intermediate drop position. The first flow rate may be determined based on the position of the spool.

[0056] The method step of exhibiting the lowering motion may comprise sending one of directly and indirectly the control signal to the control valve. The control valve is one of a counter-balance valve and a hose burst valve.

[0057] Advantageously, through the above-mentioned features, based on the input received from the sensor regarding the position of the spool as requested and required by the operator through the hand lever, the ram assembly may exhibit lowering motion in a similar motion and to the position as requested and required by the operator. In other words, the control unit may control the flow rate of the hydraulic fluid to the rod side of the ram assembly, that may influence the speed at which the ram assembly may be lifted. As a result, the ram assembly may be lowered at a speed as required by the operator i.e., based on the rate of change of movement of the spool monitored by the sensor. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[0058] The method step of exhibiting the lowering motion may comprise transmitting, a control signal to an electro-proportional control valve (EPCV). The EPCV may in response to the control signal may send a pilot signal to the counterbalance valve for regulating an extent of an opening of the counter-balance valve.

[0059] The method step of exhibiting the lowering motion may comprise transmitting flow of the hydraulic fluid to the EPCV through a shuttle valve. The shuttle valve may control flow of the hydraulic fluid to the EPCV from at least one of the primary pump and a secondary pump. The shuttle valve may allow the flow of the hydraulic fluid to the EPCV having a higher pressure between the hydraulic fluid from the primary pump and the hydraulic fluid from the secondary pump.

[0060] The method step of exhibiting the lowering motion may comprise controlling operation of the counter-balance valve through the EPCV.

[0061] The method step of exhibiting the lowering motion may comprise performing the lowering motion of the ram assembly when the spool is moved to one of the full drop position and the intermediate drop position. In the intermediate drop position of the spool, controlling the opening of the counter-balance valve in correspondence to the intermediate drop position of the spool and with spool in the full drop position, may completely open the counter-balance valve. The opening of the counter-balance valve may be a function of the position of the spool in one of the full drop position and the intermediate drop position and the opening of the counter-balance valve may be less than an opening of the spool.

[0062] Advantageously, the above-mentioned features cause the opening of the counter-balance valve may be less than an opening of the spool and may limit the maximum speed of movement of the ram assembly. In this manner, the components of the controlled actuation system may have a restricted maximum speed of the ram assembly, ensuring the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly.

[0063] The method step of exhibiting the lowering motion may comprise establishing, based on a position signal received from the sensor, a rate of change of position of the spool, and controlling speed of the opening of the counter-balance valve as a function of the rate of change of position of the spool.

[0064] The method step of exhibiting the lowering motion may comprise controlling speed of movement of the ram assembly as a function of position of the spool.

[0065] The method step of exhibiting the lowering motion may comprise restricting a speed of the opening of the counter-balance valve upon establishing, that a rate of change in position of the spool has exceeded a pre-defined threshold rate of change of position.

[0066] Advantageously, through the above-mentioned features, the opening of the counter-balance valve restricts the speed of opening of the counter-balance valve and consequently restricts the speed of lowering of the ram assembly. In this manner, the components of the controlled actuation system may have a restricted maximum speed of the ram assembly, ensuring the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly. BRIEF DESCRIPTION OF DRAWINGS [00671 The detailed description is provided with reference to the accompanying figures. It should be noted that the description and the figures are merely examples of the present subject matter and are not meant to represent the subject matter itself.

[0068] Figure 1A illustrates a side view of a working machine including a controlled actuation system, in accordance with an example of the present subject matter.

[0069] Figure IB illustrates a top-side view of the working machine including the controlled actuation system, in accordance with an example of the present subject matter.

[0070] Figure 2A illustrates a top view of a hand lever of the controlled actuation system in a neutral position accommodated in the controlled actuation system, in accordance with an example of the present subject matter.

[0071] Figure 2B illustrates a top view of the hand lever of the controlled actuation system in an intermediate drop position accommodated in the controlled actuation system, in accordance with an example of the present subject matter.

[0072] Figure 2C illustrates a top view of the hand lever of the controlled actuation system in a full drop position accommodated in the controlled actuation system, in accordance with an example of the present subject matter.

[0073] Figure 2D illustrates a top view of the hand lever in an intermediate lift position accommodated in the controlled actuation system, in accordance with an example of the present subject matter.

[0074] Figure 2E illustrates a top view of the hand lever in a full lift position accommodated in the controlled actuation system, in accordance with an example of the present subject matter.

[0075] Figure 3 illustrates schematics of a control unit of the controlled actuation system, in accordance with an example of the present subject matter.

[0076] Figure 4A illustrates a schematic of the controlled actuation system, in accordance with an example of the present subject matter.

[0077] Figure 4B illustrates the controlled actuation system of Figure 4A exhibiting a lifting motion, in accordance with an example of the present subject matter.

[0078] Figure 4C illustrates the controlled actuation system of Figure 4A exhibiting a lowering motion, in accordance with an example of the present subject matter.

[0079] Figure 4D illustrates a schematic of the controlled actuation, in accordance with another example of the present subject matter.

[0080] Figure 5 A illustrates a method to regulate movement of a ram assembly of a controlled actuation system, in accordance with an example of the present subject matter.

[0081] Figure 5B illustrates the method of Figure 5 A to regulate movement of the ram assembly of the controlled actuation system in detail, in accordance with an example of the present subject matter.

[0082] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and / or implementations consistent with the description; however, the description is not limited to the examples and / or implementations provided in the drawings. DETAILED DESCRIPTION

[0083] The present subject matter relates to aspects of a controlled actuation in working machines, such as backhoe loaders, slew excavators, telescopic handlers, forklifts, and skid-steer loaders.

[0084] Conventionally, a working machine has a working arm that is used for the purpose of lifting, moving, and placing heavy materials from one place to another. The working arm of the working machine is caused to move by an actuation system. The conventional actuation system is driven by an electronically- operated valve device at its core that cooperates with other components, such as a joystick, a control unit, a counter-balance valve, and ram for the operation of the working arm. The components of the actuation system are connected in a closed hydraulic circuit, thereby allowing implementation of a pressurized fluid to actuate the working arm mechanically coupled to the ram. The pressurized fluid is allowed to flow from the fluid reservoir through the valves at a controlled flow rate to the ram, to initiate lift or drop of the working arm. The joystick may be located inside a cab of the working machine and is operated by an operator to control movement of the working arm. The joystick and the electronic main valve can both be electronically coupled to the control unit, such that a signal generated at the joystick is used by the control unit to create a synchronized signal to be sent through the electronic main valve for controlling the electronic main valve and causing the fluid to flow at an adequate flow rate and in the appropriate direction to actuate the working arm. For instance, the joystick can be coupled to hall sensors, that on detecting the movement of the joystick send a signal to the control unit. The control unit can be, in turn, connected to the electronic main valve to control the electronic main valve. The electronic main valve comprises a number of solenoid valves which may receive a synchronized signal from the control unit to allow flow of the fluid towards the working arm based on the synchronized signal. Additionally, the counter-balance valve (CBV) that is coupled to the working arm and the solenoid valves of the electronic main valve may transmit the same synchronized signal to the CBV to regulate the flow of fluid based on the synchronized signal. In an example, the CBV may hold the working arm and may control the movement of the working arm.

[0085] In the conventional actuation system of working machines, the components, such as the electronic main valve and the joystick that are electronic components and are expensive. As a result, the cost of the conventional actuation system is high. In the same vein, the cost of maintenance and upkeep of such conventional actuation systems is also high. For instance, in case of a malfunction of any of the aforementioned electronic components, the component may require repair or replacement and, owing to the high cost of the component, the maintenance and servicing thereof may also incur high cost.

[0086] Additionally, as must be apparent from the foregoing description, the conventional actuation system employs, at its core, an electronic system, which makes the entire conventional actuation system complex. For instance, as also stated above, a synchronized signal from the joystick has to be provided to the electronic main valve as well as the counter-balance valve, such that the signal may cause the electronic main valve and the counter-balance valve to operate in a coordinated manner, so as to achieve the movement of the working arm of the machine. However, the synchronized signal through all the components of the conventional actuation system i.e., from the joystick to the electronic main valve and the counter-balance valve, may not correspond to a similar movement and opening of the counter-balance valve. In other words, since all the components may not be able to provide the same output, either in terms of the function or movement, through the same synchronized signal, the synchronized signal being sent to all the components may lead to some inconsistencies. Therefore, the required control requested by the operator based on movement of the joystick may not always translate to an appropriate output. As a result, different sub-systems, such as control mechanisms, may be required to ensure that the various components of the actuation system work in a coordinated manner to achieve the required output. Further, since the components of the conventional actuation system works on the same synchronized signal, it may be difficult to disassociate the operation of the various components from the synchronized signal. Therefore, the conventional actuation system may lack flexibility of easily incorporating a different modality of operation. Therefore, the actuation system may have to be specifically designed for a given working machine with given constraints and deploying the same actuation system for a different functionality in a different working machine may require considerable rework and effort to configure that actuation system.

[0087] The present subject matter, in one example, relates to controlled actuation in a working machine. The controlled actuation may be achieved through a controlled actuation system that employs a mechanical-hydraulic system at its core for operating a load, such as a working arm, of the machine by enabling movement of the working machine, in response to an input from an operator. The controlled actuation system of the present subject matter includes components that are hydraulically connected to each other in a closed circuit. In an example, the controlled actuation system of the present subject matter may include a ram assembly, a hand lever, the mechanical valve, a sensor, a control unit, a spool, a primary pump, a control valve, and a fluid reservoir.

[0088] The ram assembly of the controller actuation system may have a fluid-actuated plunger, also referred to as a ram, that may be movably disposed in a cylinder of the ram assembly. The fluid-actuated plunger may be hereinafter referred to as the plunger. The ram assembly, for instance, the cylinder, may be divided into a head side and a rod side by the plunger. In an example, the plunger may have a piston having a rod, the rod being connected to the load for actuating the load of the working machine. In an example, the mechanical valve of the controlled actuation system may be hydraulically coupled to the ram assembly to, indirectly, cause movement of the ram assembly. The mechanical valve may have the spool, movable inside the mechanical valve and controllable by the hand lever of the controlled actuation system. In other words, the spool is operably coupled to the hand lever to control the position of the spool inside the mechanical valve. The position of the spool can regulate closing and opening of various ports in the mechanical valve to control flow of hydraulic fluid through the mechanical valve. In turn, the sensor can monitor the position of the spool in the mechanical valve and the position of the spool can be translated, by the control unit, into movement of the plunger of the ram assembly in one direction or another, i.e., to either retract the plunger into the ram assembly (lowering movement of the load) or to protract the plunger from the ram assembly (lifting movement of the load).

[0089] The control valve is hydraulically coupled to the plunger of the ram assembly and, at the same time, the control valve may be controllable by the control unit to control flow of hydraulic fluid to one of the head side or the rod side to regulate the movement of the ram assembly, by the control unit. The primary pump can be the primary source of fluid flow that may be hydraulically coupled to the mechanical valve, the control valve, and the ram assembly, in order to form the hydraulic circuit. In addition, the primary pump can be operably coupled to the control unit to regulate the flow of the fluid from the primary pump in the hydraulic circuit. By regulating, the control unit may control the fluid flow from the primary pump in the hydraulic circuit. The control unit may control the volume of fluid flowing from the primary pump, the pressure at which the fluid may flow, and determine when the fluid flow is required, the like. The primary pump may also be hydraulically connected, as part of the hydraulic circuit, to the fluid reservoir that stores the excess hydraulic fluid in the hydraulic circuit. The hydraulic circuit may include hydraulic hoses, such as pipes and conduits, connecting various components of the controlled actuation system. The control unit may continuously monitor the conditions of the hydraulic fluid, such as fluid supply and flow parameters, by monitoring the hydraulic hoses.

[0090] In an example, the control valve may be controllable to control flow of the hydraulic fluid to regulate the movement of the ram assembly. In an example of the present subject matter, the control valve may be a counter-balance valve that may be directly or indirectly controlled by the control unit to carry out lifting and lowering operation of the ram assembly. In said example, in operation, the control unit, operably coupled to the sensor, may receive at least a position signal from the sensor corresponding to the position of the spool. In response, the control unit may control the primary pump or the counter-balance valve or both, based on the position signal received from the sensor, to regulate the flow of the hydraulic fluid to either one or both of the head side and the rod side of the ram assembly for regulating the movement of the plunger. In this example, as part of regulating the movement of the plunger, the control unit may control the flow of the hydraulic fluid, from the primary pump to either the head side or the rod side. For instance, the control unit may control the pressure of flow or the flow rate of the fluid or both. This way, the control unit may influence the movement of the plunger in the ram assembly, to cause movement of the ram assembly, when so prompted by the operator by operating the hand lever of the controlled actuation system.

[0091] In one instance, to commence the operation of the controlled actuation system, the operator may access the hand lever to operate the ram assembly based on the requirement of the operator, for instance, to perform one of a lowering motion and a lifting motion of the ram assembly. The controller actuation system of the present subject matter is so designed that when the hand lever is moved by the operator either in a direction of lifting or lowering the load, the ram assembly and, by extension, the load of the working machine, may be caused to move in correspondence with the movement of the hand lever to perform the lowering motion or the lifting motion.

[0092] In an example, the spool may be movable in at least three positions, i.e., a drop position, a neutral position, and a lift position, based on the movement of the hand lever by the operator. In the drop position, the spool may have either a full drop position or an intermediate drop position and, similarly, in the lift position, the spool may be in either a full lift position or an intermediate lift position. When the spool is moved to the drop position, for instance, either the full drop position or the intermediate drop position, the control unit may initiate and perform the lowering motion of the ram assembly. When the spool is moved to the lift position, for instance, either the full lift position or the intermediate lift position, the control unit may initiate and perform the lifting motion of the ram assembly. When the spool is in or moved to the neutral position, the control unit may cause the ram assembly to become stationary at its instantaneous position.

[0093] In response to determining that the spool is in the full lift position or the intermediate lift position, the control unit may exhibit the lifting motion of the ram assembly, by causing the supply of hydraulic fluid, through the mechanical valve, to the head side of the ram assembly. In this instance, the control unit may regulate the displacement of the primary pump and the plunger of the ram assembly may protract from the ram assembly.

[0094] In an instance in which the spool is moved to the intermediate lift position, the control unit is to cause the primary pump to supply the hydraulic fluid at a first flow rate to the head side of the ram assembly. In this example, the control unit may, based on the position signal (corresponding to the position of the spool) received from the sensor may determine the first flow rate of the hydraulic fluid from the primary pump to the head side of the ram assembly. For instance, the control unit may regulate, in the manner described above, the primary pump to supply hydraulic fluid based on the position signal received by the control unit from the sensor. In another example, in an instance in which the spool is moved to the full lift position, the control unit may cause the primary pump to supply hydraulic fluid to the head side of the ram assembly at a maximum flow rate. The maximum flow rate may be a maximum flow of hydraulic fluid to the head side to exhibit the lifting motion as requested and required by the operator. In both instances of the full lift position and the intermediate lift position, the control unit may determine the first flow rate in the lifting position based on the position of the spool.

[0095] In case of lifting motion of the ram assembly, the control unit may only engage with the primary pump to supply hydraulic fluid at the first flow rate to the head side of the ram assembly. In this instance, the control unit may not engage with the counter-balance valve and the counter-balance valve may be closed. The closed counter-balance valve may restrict the hydraulic fluid flow from the primary pump to only the head side of the ram assembly, to initiate the lifting motion of the ram assembly. In this instance, the hydraulic fluid from the rod side of the ram assembly may be allowed to exit and flow toward the fluid reservoir, as the plunger of the ram assembly protracts.

[0096] In a similar manner in response to determining that the spool is in the full drop position or the intermediate drop position, the control unit may perform a lowering motion of the ram assembly. In this instance, the control unit may cause supply of the hydraulic fluid through the mechanical valve and the counter-balance valve, to the rod side of the ram assembly for the ram assembly to exhibit the lowering motion. In this instance, i.e., in the lowering motion, the plunger of the ram assembly may retract into the ram assembly.

[0097] In the drop position of the spool, the control unit may control the opening and speed of opening of the counter-balance valve, to regulate the supply of the hydraulic fluid to the rod side of the ram assembly, to assist the ram assembly in exhibiting the lowering motion as required by the operator. In the process of assisting, the control unit may, based on the position signal received from the sensor regarding the movement of the spool, control the flow of hydraulic fluid, as explained previously, to exhibit lowering motion as required by the operator. In case the lowering motion of the ram assembly is requested by the operator by moving the hand lever to either the full drop position and the intermediate drop position, the control unit may regulate the opening of the counter-balance valve based on the position of the spool, in order to regulate the supply of the hydraulic fluid to the rod side of the ram assembly. The control unit may, based on the position signal received from the sensor, establish a control signal to be transmitted to the counter-balance valve. The control signal may be an electric signal or an electronic signal. In this example, the counter-balance valve may be electrically controllable by the control unit. Additionally, in another example, the control unit through the control signal may also control the speed of opening of the counter-balance valve, such that the opening of the counter-balance valve may be a function of the rate of change of position of the spool. For instance, if the spool is caused to move to full drop position, the control unit may control the counter-balance valve to open completely. In another instance, the spool is caused to move to the intermediate drop position, the control unit may control the opening of the counter-balance valve in correspondence to the intermediate drop position of the spool. In another example, the control unit may ensure that the opening of the counter-balance valve is less than the opening of the spool. In this manner, the control unit, by ensuring that the opening of the counter-balance valve is lesser than opening of the spool, ensures that the hydraulic fluid flow through the spool is more than the hydraulic fluid flow through the counter-balance valve. As a result, a free flow of the hydraulic fluid from the counter-balance valve to the fluid reservoir through the spool may be maintained, thereby avoiding any pressure build up, back pressure, or any resistance in fluid flow in the hydraulic connection between the spool and the counter-balance valve.

[0098] In another implementation, the counter-balance valve may be a hydraulically controllable valve. In this instance, the controlled actuation system can include an electro-proportional control valve (EPCV) that may be hydraulically coupled to the counter-balance valve and also hydraulically coupled to the primary pump. In this example, the control unit may be operably coupled with the EPCV, such that the EPCV may be controllable by the control unit to hydraulically regulate the operation of the counter-balance valve. In other words, the control unit may send a signal to the EPCV to operate the EPCV for, in turn, controlling the flow from the EPCV to the counter-balance valve. Therefore, by controlling the EPCV, instead of directly controlling the counter-balance valve, the control unit can indirectly control the opening of the counter-balance valve. In other words, by sending a control signal to the EPCV, the control unit can cause the EPCV to send a pilot signal sent to the counter-balance valve to influence the opening of the counter-balance valve, as will be explained later.

[0099] The control unit may, in response to determining that the spool is in either the full drop position or the intermediate drop position based on the position signal, send the control signal to the EPCV to control the operation of the counterbalance valve. The control unit may establish the control signal to be sent to the EPCV, based on the position signal of the spool in the intermediate drop position.

[00100] As elucidated above, the control unit may cause flow of the hydraulic fluid to the EPCV, thereby causing EPCV to generate a pilot signal at the EPCV. In this example, the EPCV may, in response to the control signal, send the pilot signal to the counter-balance valve for regulating an extent of opening of the counter-balance valve and controlling the speed of opening of the counter-balance valve. The control signal received by the EPCV from the control unit may be indicative of the pilot signal to be sent by the EPCV to the counter-balance valve. The pilot signal may be in the form of flow of the hydraulic fluid.

[00101] The counter-balance valve, on receiving the pilot signal, may be opened based on the pilot signal received from the EPCV. In this example, the opening of the counter-balance valve may cause the flow of hydraulic fluid by fluidically connecting the head side of the ram assembly to the rod side, thereby allowing hydraulic fluid to flow from the head side of the ram assembly to fill vacuum at the rod side of the ram assembly. In this example, the opening of the counter-balance valve is to create a flow path between the head side and rod side of the ram assembly and to create a return flow path from the head side to the fluid reservoir.

[00102] In an example, the opening of the counter-balance valve may be a function of the position of the spool in either the full drop position or the intermediate drop position. In other words, the opening of the counter-balance valve may be in correspondence to the position of the spool.

[00103] In an instance, the control unit may, in response to determining that the spool is positioned in the full drop position, send the control signal to the EPCV to send maximum pilot signal to the counter-balance valve, in order to completely open the counter-balance valve. The EPCV may, in response to the control signal, send the pilot signal to the counter-balance valve for regulating the counter-balance valve to open at maximum extent, and thereby achieving the lowering motion of the ram assembly as required by the operator.

[00104] As also stated above, during the lowering motion, the opening in the counter-balance valve may cause the hydraulic fluid to flow from the head side of the ram assembly to fill up the vacuum in the rod side of the ram assembly to reach an equilibrium. As the rod side of the ram assembly fills up, the volume of hydraulic fluid at the rod side becomes more than the head side, thereby causing the ram assembly to move to the lowering motion by gravity.

[00105] Additionally, due to the presence of a rod on the rod side of the ram assembly, the rod side of the ram assembly has less volume than the head side of the ram assembly and may require less hydraulic fluid to fill completely than the head side. In this regard, during the execution of the lowering motion of the ram assembly, the opening of the counter-balance valve is to cause excess hydraulic fluid from the head side of the ram assembly to be directed to a fluid reservoir through the counter-balance valve. In this instance, the excess hydraulic fluid from the head side of the ram assembly may be allowed to split from the flow and may be allowed to flow to the fluid reservoir.

[00106] In case of lowering motion of the ram assembly, in case of short fall in filling up the rod side through the hydraulic fluid from the head side, the control unit may engage with the primary pump to compensate for the vacuum at the rod side of the ram assembly for efficient lowering motion. In this example, the control unit may limit the flow from the primary pump by only supplying the amount of hydraulic fluid required to compensate for the deficiency created at the rod side of the ram assembly. In this example, the control unit may, based on the position signal received from the sensor, determine a second flow rate from the primary pump to the rod side of the ram assembly. The second flow rate may be the rate at which hydraulic fluid may flow from the primary pump to the rod side of the ram assembly for lowering motion determined by the control unit and may be established based on the position signal received from the sensor. In this instance, the control unit may regulate the displacement of the primary pump by limiting the flow of the hydraulic fluid from the primary pump to the rod side of the ram assembly while lowering motion, thereby allowing the ram assembly to perform lowering motion under gravity. Additionally, the control unit may also maintain the hydraulic fluid flow in the closed circuit based on the working conditions of the controlled actuation system of the present subject matter, such as the engine, the revolutions per minute (RPM), the pressure, and the like.

[00107] As stated above, while lowering motion of the ram assembly the hydraulic fluid flow from the primary pump may be limited, as the hydraulic fluid flow to the rod side may only be to fill up the vacuum at the rod side and to compensate for the requirement of pressurized hydraulic fluid to move the ram assembly to the lowering motion. In other words, the primary pump is only regulated by the control unit to pump hydraulic fluid to the rod side of the ram assembly at the second flow rate only, in case there is still vacuum at the rod side of the ram assembly and the hydraulic fluid from the head side is not able to completely fill up the rod side. As a result, the energy consumed by the controlled actuation system of the present subject matter in the lowering motion is comparatively less, since the primary pump is not utilized at full capacity and the lowering motion in the present subject matter is entirely caused by gravity.

[00108] In one example, as elucidated above, the control unit may, based on the position signal received from the sensor, establish, a rate of change of position of the spool and thereby control speed of opening of the counter-balance valve as a function of the rate of change of position of the spool. The control unit on establishing the rate of change in position of the spool, may control the hydraulic fluid flowing to the ram assembly to control the speed as well as the position of the ram assembly based on the input received by the operator through the hand lever. In both instances, i.e., in the lifting motion and the lowering motion, the control unit may control speed of movement of the ram assembly as a function of position of the spool.

[00109] For instance, in case of the lifting motion, the control unit may control the flow rate of the hydraulic fluid to the head side of the ram assembly to flow at the first flow rate determined by the control unit, that may influence the speed at which the ram assembly may be lifted. As a result, the ram assembly may be lifted at a speed as required by the operator, i.e., based on the rate of change of movement of the spool monitored by the sensor. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[00110] Additionally, in case of the lowering motion in which the counterbalance valve is electrically operated, the control unit may directly regulate the extent of opening and speed of opening of the counter-balance valve via the control signal sent to the counter-balance valve.

[00111] In case of the lowering motion in which the counter-balance valve is electrically operated, the counter-balance valve may perform the functions of a hose burst valve. In this instance, the control unit may directly control the counterbalance valve, for instance, to protect the controlled actuation system. As mentioned above, the hydraulic circuit can have hydraulic hoses that are monitored by the control unit to monitor the conditions of the hydraulic fluid in the hydraulic hoses. In the event of bursting of one or more hydraulic hoses in the hydraulic circuit, in addition to modulating flow of fluid to the rod side of the ram assembly to exhibit lowering movement of the ram assembly, the counter-balance valve may perform the functions of the hose burst valve of stopping the flow of hydraulic fluid in the hydraulic circuit by controlling the sudden lowering of ram in case of hydraulic hose bursting which can be disastrous in certain situations. The hydraulic hose may burst in scenarios where the fluid pressure is high, fluid temperature is high or due to vibrations experienced by the hose.

[00112] In another example, in case in which the counter-balance valve is hydraulically operated and is integrated with the EPCV, the control unit may determine the control signal to be sent to the EPCV which may be indicative of the pilot signal sent to the counter-balance valve to open the counter-balance valve. In this example, as the opening in the counter-balance valve is proportional to the pilot signal, the flow rate of hydraulic fluid at the ram assembly (i e., from the head side to the head side of the ram assembly) through the opening in the counter-balance valve may be similar to the pilot signal received by the counter-balance valve. Therefore, the flow rate of hydraulic fluid at the ram assembly (i.e., from the head side of the ram assembly to the head side of the ram assembly) may influence the speed at which the ram assembly may lower, as a result, the ram assembly may be lowered at a speed as required by the operator i.e., based on rate of change of movement of the spool monitored by the sensor. In this manner, the control unit may control speed of movement of the ram assembly as a function of position of the spool. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly.

[00113] In an example, the control unit on establishing that the rate of change in position of the spool has either reached or exceeded a pre-defined threshold rate of change of position restricts the speed of movement of the ram assembly to a predefined threshold by controlling the speed of opening of the counter-balance valve. The pre-defined threshold rate of change of position may be the pre-defined maximum rate of change in position of the spool established by the control unit. In other words, the pre-defined threshold rate of change of position may be the maximum speed at and above which the position of the spool may be changed. In this example, the pre-defined threshold may be a limited maximum speed of the movement of the ram assembly. In other words, the pre-defined threshold may be the speed at which the speed of movement of the ram assembly may be restricted. The control unit is to restrict the speed of opening of the counter-balance valve upon establishing that the rate of change in position of the spool has exceeded a predefined threshold rate of change of position.

[00114] In addition, the control unit may control the speed of opening of the counter-balance valve as a function of the rate of change of position of the spool. At the same time, the opening of the counter-balance valve caused by the pilot signal is always less than the opening of the spool. In such a manner, the components of the controlled actuation system of the present subject matter may restrict or limit the speed of protraction or retraction of the ram assembly and, consequently, ensure the safety of the operator and its surroundings in case the hand lever is inadvertently moved rapidly. In such an instance, with the restriction on the maximum speed of movement of the ram assembly, the ram assembly may not be actuated with a sudden motion in either lifting or lowering operation.

[00115] In addition to the above, in another example of the present subject matter, the counter-balance valve while being controllable by the EPCV may perform the functions of a hose burst valve, for instance, to protect the controlled actuation system. As mentioned above, the hydraulic circuit can have hydraulic hoses that are monitored by the control unit to monitor the conditions of the hydraulic fluid in the hydraulic hoses. In the event of bursting of one or more hydraulic hoses in the hydraulic circuit, in addition to modulating flow of fluid to the rod side of the ram assembly to exhibit lowering movement of the ram assembly, the counter-balance valve may perform the functions of the hose burst valve of stopping the flow of hydraulic fluid in the hydraulic circuit by controlling the sudden lowering of ram in case of hydraulic hose bursting which can be disastrous in certain situations. The hydraulic hose may burst in scenarios where the fluid pressure is high, fluid temperature is high or due to vibrations experienced by the hose.

[00116] In said example, the counter-balance valve may be indirectly operable by the control unit via the EPCV. When the control unit establishes the conditions of the bursting of the hydraulic hose in the hydraulic circuit, the control unit may send a signal to the EPCV to send a pilot signal, for instance, by way of a pilot pressure or flow of fluid, to the counter-balance valve. In response, the counter balance valve may stop the flow of hydraulic fluid in the hydraulic circuit and prevent damage. In case of the hose failure, the control unit may signal the EPCV to not send any pilot signal to the counter-balance valve and, in this manner, the EPCV may control the counter-balance valve to stop the flow of hydraulic fluid to stop the lowering motion of the ram assembly. In other words, in the event of the hose bursting or hose failure, the counter-balance valve may block any reverse flow from the rod side that may have been caused due to loss of pressure because of hose failure.

[00117] For instance, the counter-balance valve may be controlled to block the reverse flow until the pilot pressure sent to the counter-balance valve by the EPCV is inversely proportional to the load in a pilot line. Therefore, in an instance in which there is no pilot signal from the EPCV to the counter-balance valve, the flow of hydraulic fluid from the rod side may be blocked by the counter-balance valve. As an example implementation, the controlled actuation system may employ a plurality of one-way check valves for the free flow, a relief valve to control the flow in the reverse direction, and a pilot piston which lowers the relief valve setting, such that the plunger of the ram assembly can be locked in a leak-free mode. In this manner, not only is the controlled actuation system well suited for clamping applications, it is also designed to prevent the ram assembly to suddenly lower in case of hose failure.

[00118] In one example, for load lowering, the counter-balance valve may exhibit motion control by causing a directional control valve to always meter positive pressure, also under overrunning load conditions. In one implementation, therefore, the counter-balance valve may be disposed, on the working machine, in proximity of to the ram assembly, by either flange-mounting or connecting the same through a metallic conduit.

[00119] In yet other example, the control valve of the controlled actuation system may be a hose burst valve and may perform the function of protecting the controlled actuation system in the event of hose damage or hose failure, in scenarios when the fluid pressure is high, fluid temperature is high or due to vibrations experienced by the hose. In one case, the hose burst valve may secure the controlled actuation system in the situation of hose failure and may also perform the functions of the counter-balance valve of regulating the lowering and lifting of the ram assembly in the manner explained above. In said example, the hose burst valve may be directly controlled by the control unit and, therefore, may be electrically, electronically, or magnetically operable.

[00120] In view of the above aspects, the controlled actuation system of the present subject matter includes economical and inexpensive components that may be coupled in the closed circuit to achieve mirroring functionalities similar to conventional controlled actuation systems. The controlled actuation system of the present subject matter uses a mechanical-based system, for instance, one which is driven by a mechanical valve, and is capable of emulating the operation and functions of the conventional electronic-based actuation system. In other words, the controlled actuation system of the present subject matter is able to perform the same or similar functionalities as the electronically-operable conventional actuation system but with less costly components. Additionally, the energy consumed by the controlled actuation system of the present subject matter may be comparatively less than the conventional controlled actuation system, since during the lowering motion the ram assembly is allowed to operate through gravity and the primary pump is not utilized at full capacity, thereby reducing the energy. Additionally, the implementation of inexpensive products in the controlled actuation system of the present subject matter, consequently, reduces costs on maintenance and serviceability of the entire controlled actuation system.

[00121] The above aspects are further illustrated in the figures and described in the corresponding description below. It should be noted that the description and figures merely illustrate principles of the present subject matter. Therefore, various arrangements that encompass the principles of the present subject matter, although not explicitly described or shown herein, may be devised from the description and are included within its scope.

[00122] Figure 1A illustrates a side view of a working machine 102 including a controlled actuation system 100, in accordance with an example of the present subject matter. Figure IB illustrates a top-side view of the working machine 102 including the controlled actuation system 100, in accordance with an example of the present subject matter. For the sake of brevity, Figures 1A and IB have been explained in conjunction with each other.

[00123] Examples of the working machine 102 may include, but are not limited to, backhoe loaders, slew excavators, telescopic handlers, forklifts, and skid-steer loaders, for moving loads. As illustrated in Figures 1A and IB, the working machine 102 may be a telescopic handler with a working arm. In an example, the implementations of the present subject matter hereinafter have been explained with reference to the telescopic handlers. However, the implementations of the present subject matter are applicable to all types of working machines.

[00124] The controlled actuation system 100 may employ a mechanical-hydraulic system at its core for operating a load, such as a working arm 106 of the working machine 102, in response to an input from an operator. In an example, the working arm 106 may be a boom, movably mounted to the working machine 102 for moving load by implementing a working implement 108 attached to the end of the working arm 106. The working machine 102 may have a cabin 104 for the operator to access the controlled actuation system 100 of the working machine 102.

[00125] The controlled actuation system 100 of the present subject matter includes, in one example, components that are hydraulically connected to each other in a closed circuit. In an example, the controlled actuation system 100 of the present subject matter may include a ram assembly 110, a hand lever 112, the mechanical valve 114, a sensor 116, a control unit (not shown in Figure 1A and IB), a spool (not shown in Figure 1A and IB), a primary pump 118, an electro-proportional control valve (EPCV) 120, a pressure reducing valve (not shown in Figure 1A and IB), a control valve 122, a shuttle valve (not shown in Figure 1A and IB), and a fluid reservoir (not shown in Figure 1A and IB).

[00126] The ram assembly 110 of the controlled actuation system 100 may have a fluid-actuated plunger (not shown in Figure 1A and IB), also referred to as a ram, that may be movably disposed in a cylinder of the ram assembly 110. The fluid-actuated plunger may be hereinafter referred to as the plunger (shown in Figure 4B-4C as 406). The ram assembly 110, for instance, the cylinder, may be divided into a head side (not shown in Figure 1A and IB) and a rod side (not shown in Figure 1A and IB) by the plunger. In an example, the plunger may have a rod connected to a load for actuating the load of the working machine 102. In an example, the ram assembly 110 may be divided into a head side (not shown in Figure 1A and IB) and a rod side (not shown in Figure 1A and IB) by the plunger. The plunger of the ram assembly 110 may have a rod (not shown in Figures 1A and IB) connected to a load for actuating the load of the working machine 102.

[00127] The hand lever 112 may be positioned in the cabin 104 to operate and control the movement of the ram assembly 110 based on the requirement of the operator, for instance, to perform one of a lowering motion and a lifting motion of the ram assembly 110.

[00128] In an example, the hand lever 112 of the working machine 102 may control the movement of the spool. In other words, the hand lever 112 on being actuated or moved by the operator may correspondingly move the spool. In another example, the mechanical valve 114 may accommodate the spool and may also be hydraulically coupled to the ram assembly 110. In this example, the spool may be movable in the mechanical valve 114, to control flow of hydraulic fluid through the mechanical valve 114.

[00129] The controlled actuation system 100 of the present subject matter may include the sensor 116 to monitor the position of the spool in the mechanical valve 114. In an example, the sensor 116 may be a position sensor. The sensor 116 may be operably coupled to the control unit, such that the sensor 116 may instantaneously and continuously share a position signal corresponding to the position of the spool in the mechanical valve 114 to the control unit. In this example, as the hand lever 112 may be actuated by the operator, the spool may correspondingly move, and the sensor 116 may instantaneously share the position signal with the control unit.

[00130] Additionally, the control valve 122 of the controlled actuation system 100 may be hydraulically coupled to the plunger of the ram assembly 110, such that operations of the control valve 122 may be controllable by the control unit to control the flow of hydraulic fluid to either the head side or the rod side to regulate the movement of the ram assembly 110, as will be explained later. In an example, the control valve 122 may be a counter-balance valve (not shown), as will be explained with reference to Figures 4A-4C. In another example, the control valve 122 may be a hose burst valve, as will be explained with reference to Figure 4D.

[00131] The controlled actuation system 100 may also include the primary pump 118 that may be hydraulically coupled to the mechanical valve 114, the control valve 122 and the ram assembly 110, in order to form the hydraulic circuit. In this example, the primary pump 118 may provide flow of the hydraulic fluid in the hydraulic circuit of the controlled actuation system 100. The hydraulic circuit may include hydraulic hoses (not shown in Figures 1A and IB), such as pipes and conduits, connecting various components of the controlled actuation system 100. The control unit may continuously monitor the conditions of the hydraulic fluid, such as fluid supply and flow parameters, by monitoring the hydraulic hoses.

[00132] In this example, the control unit may control either the primary pump 118 or the control valve 122, based on the position signal received from the sensor 116, to regulate the flow of the hydraulic fluid to either the head side or the rod side or both of the ram assembly 110 for regulating the movement of the plunger, to thereby enable actuation of the working machine 102, as will be explained later.

[00133] Figure 2A illustrates a top view of the hand lever 112 in a neutral position 200 accommodated in the controlled actuation system 100, in accordance with an example of the present subject matter. Figure 2B illustrates a top view of the hand lever 112 in an intermediate drop position 202-1 accommodated in the controlled actuation system 100, in accordance with an example of the present subject matter. Figure 2C illustrates a top view of the hand lever 112 in a full drop position 202-2 accommodated in the controlled actuation system 100, in accordance with an example of the present subject matter. Figure 2D illustrates a top view of the hand lever 112 in an intermediate lift position 204-1 accommodated in the controlled actuation system, in accordance with an example of the present subject matter. Figure 2E illustrates a top view of the hand lever 112 in a full lift position 204-2 accommodated in the controlled actuation system 100, in accordance with an example of the present subject matter. For the sake of brevity, Figures 2A-2E have been explained in conjunction with each other.

[00134] During operation, the operator may access the hand lever 112 in the cabin 104 to operate and control the movement of the ram assembly 110, for example, to perform the lowering motion and the lifting motion of the ram assembly 110. As illustrated above, once the hand lever 112 is moved by the operator, the spool may be caused to move in correspondence with the movement of the hand lever 112, since the spool is operably coupled to the hand lever 112. Therefore, movement of the hand lever 112 is to control the position of the spool inside the mechanical valve 114. As the spool is caused to move by the hand lever 112, the spool may be movable in the mechanical valve 114 to control flow of hydraulic fluid through the mechanical valve 114.

[00135] The sensor 116 may continuously and instantaneously transmit the position signals with respect to the change in position of the spool to the control unit. In this example, the control unit may determine, from the sensor 116, the position of the spool in the mechanical valve 114.

[00136] In an example, based on the movement of the hand lever 112 actuated by the operator the spool may be moved in the mechanical valve 114 to at least three positions, i.e., a drop position 202, a neutral position 200 and a lift position 204. In order to move the ram assembly 110 in the lowering motion, the operator may move the hand lever 112 and correspondingly cause the spool to move to one of a full drop position 202-2 and an intermediate drop position 202-1, as illustrated in Figure 2C and 2B, respectively. In order to move the ram assembly 110 in the lifting motion, the operator may move the hand lever 112 and correspondingly cause the spool to move to one of a full lift position 204-2 and an intermediate lift position 204-1, as illustrated in Figure 2E and 2D, respectively.

[00137] In an instance, the operator may require to lower the ram assembly 110 to a certain position. The operator may accordingly move hand lever 112 to any position in the intermediate drop position 202-1, as illustrated in Figure 2B. Similarly, in an instance in which the operator may require to completely lower the ram assembly 110, the operator may move the hand lever 112, to any position in the full drop position 202-2, as illustrated in Figure 2C. In both instances, as the spool is operably coupled to the hand lever 112, any movement of the hand lever 112 may be translated and may cause the spool to move correspondingly. The sensor 116 may accordingly generate and send the position signals corresponding to the position of the spool to the control unit. The control unit may, based on the position signal received, initiate and perform the lowering motion of the ram assembly as per the requirement of the operator, as will be explained later.

[00138] In an instance, to cause the ram assembly to exhibit a lifting operation, the operator may move the hand lever 112 to any position in the intermediate lift position 204-1, as illustrated in Figure 2D. Similarly, in an instance in which the operator may require to completely lift the ram assembly 110, the operator may move the hand lever 112 to any position in the full lift position 204-2 as illustrated in Figure 2E. In both instances, as the spool is operably coupled to the hand lever 112, movement of the hand lever 112 may be translated and may cause the spool to move correspondingly. The sensor 116 may accordingly generate and send the position signals to the control unit. The control unit may, based on the position signal received, initiate and perform the lifting motion of the ram assembly as per the requirement of the operator, as will be explained later.

[00139] As illustrated in Figure 2A, the hand lever 112 and the spool are in neutral position 200, in such an instance, the sensor 116 may not send any position signal to the control unit. In this example, the hand lever 112 may be moved to any position in the neutral position 200 as illustrated in Figure 2 A, the working machine may remain in the neutral position. In both instances, in which the hand lever 112 may be moved from either the lift position 204 or the drop position 202 to any position in the neutral position 200, the spool may also be correspondingly caused to move to the neutral position 200. In such an instance, the sensor 116 may generate and send the position signals to the control unit. The control unit may accordingly cause the ram assembly 110 to stop at its respective position, as and when requested by the operator.

[00140] Figure 3 illustrates schematics of the control unit of the controlled actuation system, in accordance with an example of the present subject matter.

[00141] In an embodiment, the control unit 300 can be implemented as a microcontroller, a microcomputer, and / or any device that manipulates signals based on operational instructions. According to said embodiment, the control unit 300 can include a processor 302 and a device memory 304. The processor 302 can be a single processing unit or a number of units, all of which could include multiple computing units. The processor 302 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and / or any devices that manipulate signals, based on operational instructions. Among other capabilities, the processor(s) is provided to fetch and execute computer-readable instructions stored in the device memory 304. The device memory 304 may be coupled to the processor 302 and can include any computer-readable medium known in the art including, for example, volatile memory, such as Static Random Access Memory (SRAM) and Dynamic Random Access Memory (DRAM), and / or non-volatile memory, such as Read Only Memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes.

[00142] Further, the control unit 300 may include engine(s) 306 and a data 308. The engine 306 and the data 308 may be coupled to the processor 302. The engine 306, amongst other things, include routines, programs, objects, components, data structures, etc., which perform particular tasks or implement particular abstract data types. The engine 306 may also, be implemented as, signal processor(s), state machine(s), logic circuitries, and / or any other device or component that manipulate signals based on operational instructions.

[00143] In an implementation, the engine 306 include programs or coded instructions that supplement applications or functions performed by the control unit 300. Additionally, in said implementation, the data 308 can include a mapping data 310 and an other data 312. The other data 312 amongst other things, may serve as a repository for storing data that is processed, received, or generated, as a result of the execution of engine. Although the data 308 is shown internal to the control unit 300, it may be understood that the data 308 can reside in an external repository (not shown in the figure), which may be operably coupled to the control unit 300. Accordingly, the control unit 300 may be provided with I / O interface(s) 314 to communicate with the external repository to obtain information from the data 308. The I / O interface 314 may include a variety of software and hardware interface, which may enable the control unit 300 to communicate with the external repository and peripheral components of the engine 306, such as the various sensors and valves.

[00144] Figure 4A illustrates a schematic of the controlled actuation system 100, in accordance with an example of the present subject matter. Figure 4B illustrates the controlled actuation system 100 of Figure 4A exhibiting a lifting motion, in accordance with an example of the present subject matter. Figure 4C illustrates the controlled actuation system 100 of Figure 4A exhibiting a lowering motion, in accordance with an example of the present subject matter. Figure 4D illustrates a schematic of the controlled actuation, in accordance with another example of the present subject matter. For the sake of brevity, Figures 4A-4D have been explained in conjunction with each other.

[00145] As illustrated above, the control valve 122 may be the counter-balance valve. In the views depicted herein in Figures 4A-4C, the control valve 122 may be a counter-balance valve 420.

[00146] In an instance, in which the lifting motion of the ram assembly 110 is requested by the operator by moving the hand lever 112 to either the full lift position 204-2 or an intermediate lift position 204-1, the control unit 300, such as the control unit discussed above, may exhibit lifting motion based on the position signal received from the sensor, as illustrated in Figure 4B. In other words, the control unit 300 may, in response to determining that the spool 402 is in the full lift position 204-2 or the intermediate lift position 204-1, the control perform the lifting motion of the ram assembly 110.

[00147] In this example, the control unit 300 may cause the primary pump 118 to supply hydraulic fluid at a first flow rate through the mechanical valve 114 to the head side 404 of the ram assembly 110 for the ram assembly 110 to exhibit the lifting motion. The first flow rate may be the flow rate that may be required to lift the ram assembly 110 to the exact same position and at the exact same speed as requested by the operator.

[00148] In an instance in which the spool 402, similar to the spool discussed in above illustrations, is moved to one of the intermediate lift position 204-1 and the full lift position 204-2, the control unit 300 may, based on the position signal received from the sensor 116 may, determine the hydraulic fluid flow from the primary pump 118 to the head side 404 of the ram assembly 110 at the first flow rate.

[00149] In addition, the control unit 300 may, based on the inputs received from the sensor 116, also establish the rate of change in the position of the spool 402 in the mechanical valve 114. In this example, as the sensor 116 continuously shares the position signal with the control unit 300 as soon as there is a change in position of the spool 402, the control unit 300 may be based on the time interval at which the positional signal is received from the sensor 116, may establish the rate in change in position of the spool. The control unit 300 on establishing the rate of change in position of the spool 402, may control the flow rate of hydraulic fluid flowing to the head side 404 to control the speed of the ram assembly 110 along with the position of the ram assembly 110 based on the input received by the operator through the hand lever 112. In this manner, the control unit 300 may control speed of movement of the ram assembly 110 as a function of change in position of the spool 402. In this instance, the control unit 300 may determine the first flow rate based on the change in position of the spool, the rate of change in position of the spool.

[00150] In another instance in which the spool 402 is caused to move to the full lift position 204-2, the control unit 300 is to cause the primary pump 118 to supply hydraulic fluid to the head side 404 of the ram assembly 110 at a maximum flow rate. This way, the ram assembly 110 may be caused to fill up completely to move to full lift position as required by the operator.

[00151] Accordingly, the hydraulic fluid is allowed to flow through at the first flow rate from the primary pump 118 through the mechanical valve 114 to the head side 404. In this instance, a plurality of one-way check valves 401 in the closed circuit may ensure that the hydraulic fluid efficiently flows from the primary pump 118 through the mechanical valve 114 to the head side 404 of the ram assembly 110. In an example, the plurality of one-way check valves 401 may only allow the hydraulic fluid to flow through the one-way, or towards a single direction, as is desired to attain the required lifting motion of the ram assembly 110. In this instance, i.e., in the lifting motion, as the head side 404 is filled with hydraulic fluid a fluid-actuated plunger 406 of the ram assembly 110 may protract from the ram assembly 110. As illustrated above, the fluid-actuated plunger illustrated herein above corresponds to the fluid-actuated plunger plunger 406. The fluid-actuated plunger 406 may be hereinafter referred to as a plunger 406.

[00152] As a result, the flow rate of the hydraulic fluid to the head side 404 at the first flow rate may initiate lifting of the ram assembly 110 at the speed to the position as required by the operator. In this regard, the operator may have control over the position as well as the speed of the movement of the ram assembly 110. In this example, the control unit 300 may regulate the primary pump 118 to pump hydraulic fluid, at the determined first flow rate, to the head side 404, to thereby fill up the head side 404 with hydraulic fluid to exhibit lifting motion as requested by the operator. In this example, the control unit 300 may regulate the primary pump 118 to flow the amount of hydraulic fluid to the head side 404 as per the requirements to cause the ram assembly 110 to lift to the exact same position and at the exact same speed as requested by the operator.

[00153] Additionally, the control unit 300 may after regulating the primary pump 118 to pump hydraulic fluid, the control unit 300 may also maintain the flow rate of the hydraulic fluid in the hydraulic circuit, as required, based on the working conditions of the controlled actuation system of the present subject matter, such as the engine, the revolutions per minute (RPM), the pressure, and the like. In this manner, the flow rate as necessarily required to lift the ram assembly 110 to the exact same position as requested by the operator, may be maintained.

[00154] In another instance, in which the lowering motion of the ram assembly 110 is requested by the operator by moving the hand lever 112 to either the full drop position 202-2 or the intermediate drop position 202-1, the control unit 300 may exhibit the lowering motion based on the position signal received from the sensor 116, as illustrated in Figure 4A and 4C.

[00155] In such an instance, for the ram assembly 110 to exhibit the lowering motion, the control unit 300 may cause the supply of the hydraulic fluid through the mechanical valve 114 and the counter-balance valve 420, thereby causing the plunger 406 of the ram assembly 110 may retract into the ram assembly 110.

[00156] The control unit 300 may regulate the operations of the counter-balance valve 420 to thereby regulate the supply of hydraulic fluid to the rod side 400 of the ram assembly, in the lowering operation of the ram assembly 110. For instance, the operations of the counter-balance valve 420 may include the extent of an opening of the counter-balance valve 420 and the speed of opening of the counter-balance valve 420. Once the counter-balance valve 420 is opened, the opening of the counter-balance valve 420 may create a flow path between the head side 404 and the rod side 400, thereby allowing hydraulic fluid to flow from the head side 404 to the rod side 400 to fill up the vacuum at the rod side 400 to exhibit lowering movement.

[00157] In its operation in the lowering movement of the ram assembly, the control unit 300 may, in response to determining that the spool 402 is in the full drop position 202-2 or the intermediate drop position 202-1, can send the control signal to the counter-balance valve 420. In an example, the control unit 300 may either directly or indirectly control the counter-balance valve 420, i.e., the control unit 300 may directly or indirectly send the control signal to the counter-balance valve 420 to control the operations of the counter-balance valve 420. The control signal may be an electric signal or an electronic signal. In an example, in case the counter-balance valve 420 is directly controllable by the control unit 300, the counter-balance valve 420 may be electrically controllable by the control unit 300. For instance, the control unit 300 may through the control signal regulate the extent of opening of the counter-balance valve 420 and, optionally, also control the speed of opening of the counter-balance valve 420. The control unit 300, through the control signal sent to the counter-balance valve 420, may ensure that the opening of the counter-balance valve 420 is a function of the position of the spool 402 in the full drop position 202-2 or the intermediate drop position 202-1, in order to regulate the flow of hydraulic fluid.

[00158] For instance, if the spool 402 is caused to move to full drop position 202-2, the control unit 300 may control the counter-balance valve 420 to be opened completely, based on the position signal received from the sensor 116. In this manner, the hydraulic fluid may be allowed to flow from the head side 404 to the rod side 400 at a maximum flow rate, since the counter-balance valve 420 is completely opened.

[00159] In another instance, in which the spool 402 is caused to move to the intermediate drop position 202-1, the control unit 300 may control the opening of the counter-balance valve 420 in correspondence to the intermediate drop position 202-1 of the spool 402, as required by the operator. In this example, the control unit 300 may ensure, while determining the control signal, that the opening of the counter-balance valve 420 is a function of change in position of the spool 402 i.e., in full drop position 202-2 or in intermediate drop position 202-1. In an instance, in which the control unit 300 establishes that the spool 402 is positioned in the full drop position 202-2, the control unit 300 may transmit the control signal to the EPCV 120, to send maximum pilot signal to the counter-balance valve 420, in order to completely open the counter-balance valve 420.

[00160] Additionally, in order to determine the control signal, the control unit 300 may, based on the position signal received from the sensor 116, may also initially establish the rate of change in the position of the spool 402 in the mechanical valve 114. Based on the rate of change of position of the spool, the control unit 300 may control a speed of opening of the counter-balance valve 420 as a function of the rate of change of position of the spool 402. In other words, the control unit 300 may through the control signal control the speed of movement of the ram assembly 110 as a function of the change of position of the spool 402.

[00161] In one case, on establishing the rate of change in position of the spool 402, the control unit 300 may determine if the rate of change in position of the spool has either reached or exceed a pre-defined threshold rate of change of position. The control unit 300 may, in such a case, restrict the speed of movement of the ram assembly 110 to a pre-defined threshold through the control signal which is indicative of the extent of opening of the counter-balance valve 420 and the speed of opening of the counter-balance valve 420. In this way, the control unit 300 may limit the maximum rate of change in position of spool 402, i.e., the maximum speed of movement of the ram assembly 110. In this example, through the control signal, the control unit 300 may ensure that the area of the opening of the counter-balance valve 420 is always less than the opening of the spool 402. In this manner, the components of the controlled actuation system 100 may have a restricted maximum speed of the ram assembly 110, ensuring the safety of the operator and its surroundings in case the hand lever 112 is inadvertently moved rapidly.

[00162] In an example, the counter-balance valve 420 may be an electrically-controllable valve, i.e., controlled directly by a control signal, for instance, an electrical or an electronic signal, from the control unit 300. On receiving the control signal, the counter-balance valve 420 may be caused to open, corresponding to the control signal. In this instance, the counter-balance valve 420 can be a solenoid-operated valve and is directly controllable by the control signal. In this example, in case the counter-balance valve 420 may be electrically-controllable valve, the counter-balance valve 420 may perform the functions of a hose burst valve and may be directly controllable by the control unit 300 to perform the functions of the hose burst valve.

[00163] In another example, as illustrated in Figure 4A and 4C, the counterbalance valve 420 may be hydraulically operated and is operably coupled to the EPCV 120. In this instance, the EPCV 120 may be hydraulically coupled to the counter-balance valve 420 and also hydraulically coupled to the primary pump 118. The EPCV 120 may be controllable by the control unit 300 to, in turn, can cause the EPCV 120 to hydraulically regulate the operation of the counter-balance valve 420. The EPCV 120 may be operably coupled to the control unit 300, such that the EPCV 120 may be controllable by the control unit 300 to, in turn, regulate the operations of the counter-balance valve 420. The operations of the counter-balance valve 420 may include regulating the opening of the counter-balance valve 420 and controlling the speed of opening of the counter-balance valve. In this manner, the control unit 300 may control speed of movement of the ram assembly 110 as a function of change in position of the spool. For instance, the control unit 300 may cause the hydraulic fluid to flow through the EPCV 120, for the EPCV 120 to generate a pilot signal which is, as an example, a hydraulic signal or in the form or flow of hydraulic fluid from the EPCV 120 to the counter-balance valve 420. In other words, the control unit 300 may transmit the control signal to the EPCV 120, thereby causing hydraulic fluid to flow to the EPCV 120 to generate a pilot pressure at EPCV 120. In this instance, i.e., in the lowering motion, the control unit 300 can transmit flow of the hydraulic fluid to the EPCV 120 through a shuttle valve 418.

[00164] In another example, in which case the primary pump 118 may be insufficient in providing flow to the EPCV 120, a secondary pump 408 may be provided in the controlled actuation system 100. To fulfil the flow requirement for lowering motion of the ram assembly 110. In this example, the shuttle valve 418 can be provided between the primary pump 118 and the secondary pump 408 with an outlet line from the shuttle valve 418 to the EPCV. The shuttle valve 418 can, thus, control flow of the hydraulic fluid to the EPCV 120 from either the primary pump 118 or the secondary pump 408 or both. The shuttle valve 418 is so designed so as to allow the flow of the hydraulic fluid to the EPCV 120 from between the primary pump 118 or the secondary pump 408 based on the one having a higher pressure between the two. In other words, the shuttle valve 418 may select either of the primary pump 118 and the secondary pump 408 depending on which of the two is supplying fluid at a higher pressure.

[00165] In addition, a pressure reducing valve 410 may receive flow of hydraulic fluid from the shuttle valve 418 before the fluid reaches the EPCV 120. The pressure reducing valve 410 may maintain the constant pressure at the input of the EPCV 120, thereby facilitating the EPCV 120 to send the pilot signal as the output to the counter-balance valve 420. In addition, an accumulator 412 may be provided between the pressure reducing valve 410 and the EPCV 120. The accumulator 412 may maintain constant pressure, in order to avoid any inconsistencies and maintain the constant pressure. Additionally, at least one of the plurality of one-way check valves 401 may also be provided between the pressure reducing valve 410 and the EPCV 120, in order to only allow hydraulic fluid as control signal to flow directly from pressure reducing valve 410 to the EPCV 120. Therefore, in response to the pilot signal, the flow rate of hydraulic fluid in the ram assembly 110 (i e., from the head side to the rod side) through the opening in the counter-balance valve 420 may be controlled to regulate the extent and the speed at which the ram assembly 110 may lower.

[00166] In both instances as stated above, i.e., the counter-balance valve is a hydraulically operated integrated with the EPCV 120 or is an electrically controllable valve, the control unit 300 through the control signal may cause the opening of the counter-balance valve 420 to be less than an opening of the spool i.e., change in position of the spool 402 in the mechanical valve 114. In this manner, the control unit 300 may ensure that the hydraulic fluid flow through the spool 402 is more than the hydraulic fluid flow through the counter-balance valve 420. As a result, a free flow of the hydraulic fluid from the counter-balance valve 420 to the fluid reservoir 416 through the spool may be maintained, thereby avoiding any pressure build up, back pressure or any resistance in fluid flow in the hydraulic connection between the spool 402 and the counter-balance valve 420.

[00167] In this manner, in both instances as stated above, the control unit 300 may ensure through the control signal to control speed movement of the ram assembly 110 as a function of the rate of change of position of the spool 402. The control unit may control the hydraulic fluid flowing to the ram assembly 110 to control the speed as well as the position of the ram assembly 110 based on the input received by the operator through the hand lever 112.

[00168] In both instances, in lowering motion of the ram assembly 110, in case of short fall in filling up the rod side 400 of the ram assembly 110 through the hydraulic fluid from the head side 404 of the ram assembly 110, the control unit 300 may engage with the primary pump 118 to compensate the vacuum at the rod side 400 of the ram assembly 110 for efficient lowering motion. In this example, the control unit 300 may limit the flow from the primary pump 118 by only supplying the amount of hydraulic fluid required to compensate for the deficiency created at the rod side 400 of the ram assembly. In this example, the control unit 300 may, based on the position signal received from the sensor 116, determine the hydraulic fluid flow rate from the primary pump 118 to the rod side 400. The control unit 300 may regulate the primary pump 118 to pump hydraulic fluid at a second flow rate to the rod side 400. The second flow rate may be the flow rate at which hydraulic fluid may flow from the primary pump 118 to the rod side 400 for lowering motion. The control unit 300 may establish the second flow rate based on the position signal received from the sensor 116 and based on the conditions illustrated above, only the amount of hydraulic fluid to compensate for deficiency in rod side 400. In this instance, the control unit 300 may regulate the displacement of the primary pump 118 by limiting the flow of the hydraulic fluid from the primary pump 118 to the rod side while lowering motion, thereby allowing the ram assembly 110 to perform lowering motion under gravity. Additionally, the control unit 300 may also maintain the hydraulic fluid flow in the closed circuit based on the working conditions of the controlled actuation system of the present subject matter, such as the engine, the revolutions per minute (RPM), the pressure, and the like.

[00169] During the lowering motion, the opening in the counter-balance valve 420 may cause the hydraulic fluid to flow from the head side 404 of the ram assembly 110 to reach an equilibrium. As the rod side 400 of the ram assembly fills up, the volume of hydraulic fluid at the rod side 400 becomes more than the head side 404, thereby causing the ram assembly 110 to move to the lowering motion by gravity.

[00170] Additionally, due to the presence of a rod 414 on the rod side 400 of the ram assembly 110, the rod side 400 of the ram assembly 110 may have less volume than the head side 404 of the ram assembly 110 and may require less hydraulic fluid to fill completely than the head side 404. Therefore, in the lowering motion, the excess hydraulic fluid from the head side 404 of the ram assembly 110 may be allowed to split from the fluid flow and may be allowed to flow via the counterbalance valve 420 through the mechanical valve 114 to the fluid reservoir 416. In order to allow excess hydraulic fluid to efficiently flow from the head side 404 through the counter-balance valve 420 and to the fluid reservoir 416, at least one of the plurality of one-way check valves 401 may be provided, such that the hydraulic fluid flowing from the head side 404 to the fluid reservoir 416 may have only the one way to flow.

[00171] As stated above, while lowering motion of the ram assembly 110 the hydraulic fluid flow from the primary pump 118 may be limited, as the hydraulic fluid flow may be to only compensate for the requirement of pressurized hydraulic fluid at the rod side 400 to move the ram assembly 110 to the lowering motion. In other words, the primary pump 118 is only regulated by the control unit 300 to pump hydraulic fluid to the rod side 400 at the second flow rate, only in case there is still vacuum at the rod side 400 of the ram assembly and the hydraulic fluid from the head side 404 is not able to completely fill up the rod side 400. As a result, the energy consumed by the controlled actuation system 100 of the present subject matter in the lowering motion is comparatively less, since the primary pump 118 is not utilized at full capacity and the lowering motion in the present subject matter is entirely caused by gravity.

[00172] In view of the above-mentioned implementations, the control unit 300 may perform the operation explained herein and regulate the components of the controlled actuation system 100 as stated above, based on a pre-defined matrix which captures the functionalities and operations of the control unit 300 explained above. The pre-defined matrix may be recorded in the data 308 of the control unit 300 and may be employed by the control unit 300 for carrying out the operation of the controlled actuation system 100. Therefore, the pre-defined matrix may be a logic mapping table which is formed as a matrix between position signal of the spool received from the sensor, and the parameters to control the components of the controlled actuation system 100 to perform lifting motion and lowering motion of the ram assembly based on the requirement of the operator. In an example, the parameters in the pre-defined matrix table can include different combinations of the first flow rate from the primary pump 118, the conditions for sending control signal to the counter-balance valve 420, and an amount of opening of the counter-balance valve 420 corelated with the spool position. In addition, in other examples, the predefined matrix may include the conditions of sending the control signal to the EPCV 120, a second flow rate from the primary pump 118, a speed of opening of the counter-balance valve 420 correlated with the rate of change of position of the spool. The control unit 300 may employ the pre-defined matrix in the manner explained above to control the components of the controlled actuation system 100 for various operations also described above.

[00173] In an example as illustrated in Figures 4A and 4C in which the counterbalance valve is hydraulically operable, the counter-balance valve 420 may, additionally or alternatively, function as a hose burst valve. In other words, the counter-balance valve 420 may be controllable by the EPCV to perform the functions of the hose burst valve to stop the flow of hydraulic fluid in response to determining the condition of bursting of the hydraulic hose in the hydraulic circuit. As mentioned above, the hydraulic circuit can have hydraulic hoses that are monitored by the control unit 300 to monitor the conditions of the hydraulic fluid in the hydraulic hoses. In the event of bursting of one or more hydraulic hoses in the hydraulic circuit, in addition to modulating flow of fluid to the rod side of the ram assembly 110 to exhibit lowering movement of the ram assembly 110, the counter-balance valve 420 may perform the functions of the hose burst valve of stopping the flow of hydraulic fluid in the hydraulic circuit by controlling the sudden lowering of ram assembly 110 in case of hydraulic hose bursting which can be disastrous in certain situations. The hydraulic hose may burst in scenarios where the fluid pressure is high, fluid temperature is high or due to vibrations experienced by the hose.

[00174] In said example, the counter-balance valve 420 may be indirectly operable by the control unit 300 via the EPCV 120. When the control unit 300 establishes the conditions of the bursting of the hydraulic hose in the hydraulic circuit, the control unit 300 may send a signal to the EPCV 120 to send a pilot pressure to the counter-balance valve 420, in response to which, the counter-balance valve 420 may stop the flow of hydraulic fluid in the hydraulic circuit and prevent damage. For instance, in the event of the hose bursting or hose failure, the counterbalance valve 420 may allow free flow into the rod side 400 of the ram assembly 110 and block the reverse flow that may have been caused due to loss of pressure because of hose bursting or hose failure, this may be done until the pilot pressure sent to the counter-balance valve 420 is inversely proportional to the load in a pilot line. In other words, in an instance in which there is no pilot pressure in the pilot line, the flow of hydraulic fluid may be blocked.

[00175] In another instance, as illustrated in Figure 4D, the control valve 122 may be the hose burst valve 422 and may perform the function of protecting the controlled actuation system in the event of hose damage or hose failure, in scenarios when the fluid pressure is high, fluid temperature is high or due to vibrations experienced by the hose. The hose burst valve 422 as illustrated in Figure 4D may secure the controlled actuation system 100 in the situation of hose failure. In this example, the hose burst valve 422 may perform same functions as the counterbalance valve of regulating the lowering and lifting of the ram assembly 110 in the manner as illustrated above in Figures 4A-4C. As illustrated in Figure 4D, the hose burst valve 422 may be electronically controlled by the control unit 300. In this example, the control unit 300 may establish the conditions of the bursting of the hydraulic hose in the hydraulic circuit and may send electric signal to the hose burst valve 422 in respect of the condition of bursting of the hydraulic hose. In this example, the hose burst valve 422 may receive inputs regarding the hydraulic hose in the hydraulic circuit from the control unit 300, and in response to determining the condition of bursting of a hydraulic hose in the hydraulic circuit, the hose burst valve 422 may stop the flow of hydraulic fluid.

[00176] Figure 5A illustrates a method 500 to regulate movement of the ram assembly of the controlled actuation system, in accordance with an example of the present subject matter. Figure 5B illustrates method 500 of Figure 5A to regulate movement of the ram assembly of the controlled actuation system in detail, in accordance with an example of the present subject matter.

[00177] The order in which the method 500 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any appropriate order to execute the method 500 or another method. Additionally, individual blocks may be deleted from the method 500 without departing from the aspects of the subject matter described herein.

[00178] As illustrated in Figure 5A, the method 500 illustrates a method to regulate movement of the ram assembly of the controlled actuation system. The controlled actuation system may include a sensor, a primary pump, a control valve, a spool, a mechanical valve, a hand lever, a ram assembly. The ram assembly may have a head side and a rod side. The spool may be moved to a lift position or a drop position.

[00179] At block 502, determining, from the sensor, a position of a spool of a mechanical valve, in which the spool is movable in the mechanical valve to control flow of hydraulic fluid through the mechanical valve. The position of the spool is controllable by the hand lever.

[00180] In case it is established the position of the spool is in lift position, at block 504, causing, in response to determining that the spool is in a lift position, the primary pump to supply the hydraulic fluid, through the mechanical valve, to a head side of the ram assembly for the ram assembly to exhibit the lifting motion.

[00181] In case it is established the position of the spool is in drop position, at block 506, causing, in response to determining that the spool is in a drop position, the primary pump to supply the hydraulic fluid through the mechanical valve and the control valve, to a rod side of the ram assembly for the ram assembly to exhibit a lowering motion. The causing includes controlling the control valve to regulate the supply of the hydraulic fluid to the rod side of the ram assembly.

[00182] Figure 5B illustrates the method 500 illustrated in Figure 5A in detail, which states the steps to regulate the movement of the ram assembly in the controlled actuation system.

[00183] At block 502, determining, from the sensor, a position of a spool of the mechanical valve. The spool may be movable in the mechanical valve to control flow of hydraulic fluid through the mechanical valve. The position of the spool is controllable by the hand lever. In this step, the position of the spool may be determined from the sensor.

[00184] At block 508, determining whether the spool is in neutral position. If, based on the position signals from the sensor it is established that the spool is in neutral position, the method 500 may follow the Yes path to block 510. Accordingly, at block 510, no action may be taken.

[00185] In another example, at block 508, in case it is established that the spool is not in neutral position. Accordingly, at block 512, it is established whether the spool is in the lift position. Based on the position signals from the sensor it is established that the spool is in the lift position. Accordingly, at block 514, performing the lifting motion of the ram assembly, in response to determining that the spool is in one of the full lift position or the intermediate lift position. In this instance, at block 504, causing, in response to determining that the spool is in the lift position, the primary pump to supply hydraulic fluid, through the mechanical valve, to the head side of the ram assembly for the ram assembly to exhibit the lifting motion. The exhibiting of the lifting motion of the ram assembly may be performed in response to determining that the spool is in one of the full lift position and an intermediate lift position. In this instance, i.e., in the lifting motion, the plunger of the ram assembly may protract from the ram assembly. In an instance in which the spool is moved to the intermediate lift position, causing the primary pump to supply hydraulic fluid at the first flow rate to the head side of the ram assembly. Determining first flow rate of the hydraulic fluid flow from the primary pump to the head side of the ram assembly based on the position signal received from the sensor. In an instance in which the spool is moved to the full lift position, causing the primary pump to supply hydraulic fluid at the maximum flow rate to the head side of the ram assembly, in response to determining that position of the spool is in the full lift position.

[00186] In another example, at block 512, in case it is established that the spool is not in lift position. Accordingly, at block 516, it is established whether the spool is in the drop position. At block 518, performing the lowering motion of the ram assembly, in response to determining that the spool is in one of the full drop position and the intermediate drop position. Accordingly, at block 506, causing, in response to determining that the spool is in the drop position, the primary pump to supply the hydraulic fluid through the mechanical valve and the control valve, to the rod side of the ram assembly for the ram assembly to exhibit the lowering motion. Additionally, the causing includes, controlling the control valve to regulate the supply of the hydraulic fluid to the rod side of the ram assembly, to assist the ram assembly in exhibiting the lowering motion. The exhibiting the lowering motion of the ram assembly, at block 506 is in response to determining that the spool is in one of the full drop position and the intermediate drop position. Additionally, the exhibiting the lowering motion at block 506 may include supplying, the hydraulic fluid at a first flow rate to the head side of the ram assembly, in response to determining that position of the spool is in the intermediate drop position, wherein the first flow rate is determined based on the position of the spool.

[00187] In an example, the exhibiting the lowering motion of the ram assembly at block 506, may include sending one of directly and indirectly the control signal to the control valve, such that the control valve may be one of a counter-balance valve and a hose burst valve.

[00188] The embodiments illustrated hereinafter have been illustrated with reference to the control valve being the counter-balance valve. In this example, the controlled actuation system includes the counter-balance valve.

[00189] In an example, at block 516, determining that the spool is in the full drop position or the intermediate drop position. In both instances, in order to exhibit lowering motion at block 506, transmitting the control signal to the electroproportional control valve (EPCV), in response to determining that the spool is in the full drop position or the intermediate drop position, wherein the EPCV is hydraulically coupled to the counter-balance valve and the EPCV is operably coupled to the control unit 300.

[00190] In order to exhibit the lowering motion, at block 506, transmitting flow of the hydraulic fluid to the EPCV Through a shuttle valve, wherein the shuttle valve is to control flow of the hydraulic fluid to the EPCV from at least one of the primary pump and a secondary pump, wherein the shuttle valve is to allow the flow of the hydraulic fluid to the EPCV having a higher pressure between the hydraulic fluid from the primary pump and the hydraulic fluid from the secondary pump.

[00191] In an instance, in case determining that the spool is positioned in the full drop position, sending the hydraulic control signal to the EPCV, to send maximum pilot signal to the counter-balance valve, in order to completely open the counterbalance valve.

[00192] In another instance, in case determined that the spool is positioned in the intermediate drop position. In another instance, the spool is caused to move to the intermediate drop position, controlling the operation of the counter-balance valve. In another example, controlling the operation of the counter-balance valve through the EPCV.

[00193] In both instances, performing in full drop position and in intermediate drop position, to exhibit lowering motion at block 506, the EPCV in response to the control signal may send a pilot signal to the counter-balance valve for regulating an extent of an opening of the counter-balance valve. Accordingly, controlling the operation of the counter-balance valve through the EPCV.

[00194] In both instances, exhibiting the lowering motion of the ram assembly at block 506, when the spool is moved to the full drop position or the intermediate drop position, when spool in the intermediate drop position of the spool, controlling the opening of the counter-balance valve in correspondence to the intermediate drop position of the spool and with spool in the full drop position, to completely open the counter-balance valve. The opening of the counter-balance valve is a function of the position of the spool in the full drop position or the intermediate drop position and the opening of the counter-balance valve is less than an opening of the spool. Additionally, controlling the opening of the counter-balance valve in correspondence to the intermediate drop position of the spool.

[00195] Controlling the opening of the counter-balance valve in correspondence to the intermediate drop position of the spool, as required by the operator. In this example, that the controlling includes controlling the opening of the counterbalance valve, such that the opening of the counter-balance valve is less than an opening of the spool. In this example, the opening of the spool may be the change in position of the spool in the mechanical valve caused by the movement of the hand lever. In this manner, by ensuring that the opening of the counter-balance valve is lesser than opening of the spool, the hydraulic fluid flow through the spool 402 may be more than the hydraulic fluid flow through the counter-balance valve.

[00196] In another example, to exhibit lowering motion at block 506, also establishing the change in position of the spool and the rate of change in position of the spool based on the position signal received from the sensor. Controlling speed of movement of the ram assembly such that the speed of movement of the ram assembly is a function position of the spool in the mechanical valve. Additionally, controlling speed of movement of the ram assembly is based on the rate in change in position of the spool established based on the position signal received from the sensor. Based on determining the rate in change in position of the spool, restricting the speed of movement of the ram assembly to a pre-defined threshold upon establishing, based on the position signal received from the sensor, that the rate of change in position of the spool has exceeded the pre-defined threshold rate of change of position.

[00197] In an instance, as illustrated above, in which the counter-balance valve may exhibit the functions of the hose burst valve. In this instance, while exhibiting the lowering motion of the ram assembly at block 506, the control signal corresponding to conditions of a hydraulic hose may be received either directly or indirectly at the counter-balance valve from the control unit. In response to receiving the control signal, the counter-balance valve may stop the flow of hydraulic fluid considering the condition of bursting of a hydraulic hose in the hydraulic circuit.

[00198] The method 500 as described above may be performed by programmed computing devices, such as a control unit 300 as depicted in Figures 1-4. Accordingly, as an example, in the description of Figures 5A and 5B, the components of the controlled actuation system corresponds to the components of the controlled actuation system 100 as described with respect to Figures 1-4. Therefore, in the description of Figures 5 A and 5B, the controlled actuation system in method 500 may correspond to the controlled actuation system 100. Similarly, the sensor corresponds to the sensor 116, the primary pump corresponds to the primary pump 118, the control valve corresponds to the control valve 122. The spool corresponds to the spool 402, the mechanical valve corresponds to the mechanical valve 114 and the hand lever corresponds to the hand lever 112. The lift position corresponds to the lift position 204, the ram assembly corresponds to the ram assembly 110 and the head side corresponds to the head side 404. The drop position corresponds to the drop position 202 and the rod side corresponds to the rod side 400. The neutral position may correspond to the neutral position 200. A lift position may correspond to the lift position 204. An intermediate drop position may correspond to the intermediate drop position 202-1 and a full drop position may correspond to the full drop position 202-2. An intermediate lift position may correspond to the intermediate lift position 204-1 and a full lift position may correspond to the full lift position 204-2. A plunger may correspond to the plunger 406. A counter-balance valve corresponds to the counter-balance valve 420 and a hose burst valve corresponds to the hose burst valve 422. An electro-proportional control valve (EPCV) corresponds to the EPCV 120. A shuttle valve corresponds to the shuttle valve 418. A secondary pump corresponds to the secondary pump 408.

[00199] In view of the above aspects, the controlled actuation system 100 of the present subject matter comprises mechanically operated components in a closed hydraulic circuit. The controlled actuation system 100 of the present subject matter includes economical and inexpensive components that may be mechanically coupled in the closed circuit to achieve mirroring functionalities as the conventional controlled actuation systems. The controlled actuation system 100 of the present subject matter is capable of emulating the operation and functions of the electronically-operable conventional actuation system. Therefore, the controlled actuation system 100 of the present subject matter is able to perform the same or similar functionalities as the electronically-operable conventional actuation system but with less costly components. For instance, a mechanical valve 114, may be implemented in the controlled actuation system 100 of the present subject matter i.e., less costly and equally functional as compared to the electronic main valve used in the conventional controlled actuation system. Therefore, the controlled actuation system 100 of the present subject matter by implementing inexpensive components, as illustrated hereinabove, in a mechanically coupled closed circuit achieves improved functionalities with respect to the movement of the ram assembly 110. Additionally, the energy consumed by the controlled actuation system 100 of the present subject matter may be comparatively less than the conventional controlled actuation system, since during the lowering motion the ram assembly 110 is allowed to operate through gravity and the primary pump 118 is not utilized at full capacity, thereby reducing the energy. Additionally, the implementation of inexpensive products in the controlled actuation system of the present subject matter, consequently, reduces costs on maintenance and serviceability of the entire controlled actuation system.

[00200] Although examples of the controlled actuation system 100 and the control unit 300 thereof have been described in language specific to structural features and / or methods, it is to be understood that the appended claims are not limited to the specific features described. Rather, the specific features are disclosed as examples of the controlled actuation system 100 and the control unit 300. CLAUSES 1. A controlled actuation system (100) for a working machine (102), the controlled actuation system (100) comprising: a ram assembly (110) having a fluid-actuated plunger (406) movably disposed therein, the ram assembly (110) divided into a head side (404) and a rod side (400) by the fluid-actuated plunger (406), wherein the fluid-actuated plunger (406) has a rod (414) connected to a load for actuating the load; a mechanical valve (114) hydraulically coupled to the ram assembly (110), the mechanical valve (114) having a spool (402) movable therein to control flow of a hydraulic fluid through the mechanical valve (114), wherein movement of the spool (402) is controllable by a hand lever (112); a sensor (116) to monitor a position of the spool (402) in the mechanical valve (114); a control valve (122) hydraulically coupled to the fluid-actuated plunger (406), wherein the control valve (122) is controllable to control flow of the hydraulic fluid to one of the head side (404) and the rod side (400) to regulate the movement thereof; a primary pump (118) hydraulically coupled to the mechanical valve (114), the control valve (122) and the ram assembly (110) to form a hydraulic circuit, wherein the primary pump (118) is configured to provide a flow of the hydraulic fluid in the hydraulic circuit of the controlled actuation system (100); and a control unit (300) operably coupled to the sensor (116) to receive at least a position signal corresponding to the position of the spool (402) of the mechanical valve (114), wherein the control unit (300) is configured to control at least one of the primary pump (118) and the control valve (122), based on the position signal, to regulate the flow of the hydraulic fluid to at least one of the head side (404) and the rod side (400) of the ram assembly (110) for regulating the movement of the fluid-actuated plunger (406). 2. The controlled actuation system (100) of clause 1, wherein the control unit (300) is configured to perform a lifting motion of the ram assembly (110), in response to determining that the spool (402) is in one of a full lift position (204-2) and an intermediate lift position (204-1), by causing supply of the hydraulic fluid, through the mechanical valve (114), to the head side (404) of the ram assembly (110) for the ram assembly (110) to exhibit the lifting motion. 3. The controlled actuation system (100) of clause 2, wherein the control unit (300), in the intermediate lift position (204-1) of the spool (402), is configured to cause the primary pump (118) to supply the hydraulic fluid at a first flow rate to the head side (404) of the ram assembly (110), wherein the first flow rate is determined based on the position of the spool (402). 4. The controlled actuation system (100) of clause 1, wherein the control valve (122) is a counter-balance valve (420). 5. The controlled actuation system (100) of clause 4, wherein the control unit (300) is configured to perform a lowering motion of the ram assembly (110), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1), by causing supply of the hydraulic fluid through the mechanical valve (114) and the counter-balance valve (420), to the rod side (400) of the ram assembly (110) for the ram assembly (110) to exhibit the lowering motion. 6. The controlled actuation system (100) of clause 4, wherein the control unit (300) is configured to control the counter-balance valve (420) to regulate supply of the hydraulic fluid to the rod side (400) of the ram assembly (110), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1). 7. The controlled actuation system (100) of clause 4, comprising an electroproportional control valve (EPCV) (120) hydraulically coupled to the counterbalance valve (420), wherein the EPCV (120) is operably coupled to the control unit (300) and is controllable to hydraulically regulate an operation of the counterbalance valve (420). 8. The controlled actuation system (100) of clause 4, the control unit (300), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1), is configured to send a control signal to a EPCV (120), wherein, in response to the control signal, the EPCV (120) is to send a pilot signal to the counter-balance valve (420) for regulating an opening of the counter-balance valve (420), wherein the control unit (300) is to regulate an extent of the opening of the counter-balance valve (420). 9. The controlled actuation system (100) of clause 8, wherein the pilot signal is in form of flow of the hydraulic fluid, and the control unit (300) is configured to cause flow of the hydraulic fluid to the EPCV (120) to generate the pilot signal at the EPC V (120). 10. The controlled actuation system (100) of clause 9, comprising: a secondary pump (408) to provide hydraulic fluid to the EPCV (120), wherein the secondary pump (408) is controllable by the control unit (300) to provide the flow of the hydraulic fluid to the EPCV (120); and a shuttle valve (418) to control flow of the hydraulic fluid to the EPCV (120) from at least one of the primary pump (118) and the secondary pump (408), wherein the shuttle valve (418) is to allow the flow of the hydraulic fluid to the EPCV (120) having a higher pressure between the hydraulic fluid from the primary pump (118) and the hydraulic fluid from the secondary pump (408). 11. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420) is a function of the position of the spool (402) in the full drop position (202-2). 12. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420) is less than an opening of the spool (402) in the full drop position (202-2). 13. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420) is a function of the position of the spool (402) in the intermediate drop position (202-1). 14. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420) is less than an opening of the spool (402) in the intermediate drop position (202-1). 15. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420) is to create a flow path between the head side (404) and rod side (400) of the ram assembly (110) and to create a return flow path from the head side (404) to a fluid reservoir (416). 16. The controlled actuation system (100) of clause 8, wherein the opening of the counter-balance valve (420), during execution of a lowering motion of the ram assembly (110), is to cause excess hydraulic fluid from the head side (404) of the ram assembly (110) to be directed to a fluid reservoir (416) through the counterbalance valve (420). 17. The controlled actuation system (100) of clause 4, wherein the control unit (300) is configured to: establish, based on the position signal received from the sensor (116), a rate of change of position of the spool (402), and control a speed of opening of the counter-balance valve (420) as a function of the rate of change of position of the spool (402). 18. The controlled actuation system (100) of clause 17, wherein the control unit (300) is configured to restrict the speed of opening of the counter-balance valve (420) upon establishing that a rate of change in position of the spool (402) has exceeded a pre-defined threshold rate of change of position. 19. The controlled actuation system (100) of clause 4, wherein the counter-balance valve (420) is to perform function of a hose burst valve (422) to stop the flow of hydraulic fluid in response to determining a condition of bursting of a hydraulic hose in the hydraulic circuit. 20. The controlled actuation system (100) of clause 1, wherein the control valve (122) is a hose burst valve (422), wherein the hose burst valve (422) is to stop the flow of hydraulic fluid in response to determining a condition of bursting of a hydraulic hose in the hydraulic circuit. 21. A control unit (300) for a controlled actuation system (100) of a working machine (102), the control unit (300) being coupled to a sensor (116), a primary pump (118), and a control valve (122) to regulate movement of a ram assembly (110) of the controlled actuation system (100), wherein the control unit (300) is configured to: determine, from the sensor (116), a position of a spool (402) of a mechanical valve (114), wherein the spool (402) is movable in the mechanical valve (114) to control flow of a hydraulic fluid through the mechanical valve (114), wherein the position of the spool (402) is controllable by a hand lever (112); cause, in response to determining that the spool (402) is in lift position (204), the primary pump (118) to supply the hydraulic fluid, through the mechanical valve (114), to a head side (404) of the ram assembly (110) for the ram assembly (110) to exhibit a lifting motion; and cause, in response to determining that the spool (402) is in drop position (202), the primary pump (118) to supply the hydraulic fluid through the mechanical valve (114) and the control valve (122), to a rod side (400) of the ram assembly (110) for the ram assembly (110) to exhibit a lowering motion, wherein, in the drop position (202) of the spool (402), the control unit (300) is configured to control the control valve (122) to regulate the supply of the hydraulic fluid to the rod side (400) of the ram assembly (110) to assist the ram assembly (110) in exhibiting the lowering motion. 22. The control unit (300) of clause 21, wherein the control unit (300) is configured to exhibit lifting motion in response to determining that the spool (402) is in one of a full lift position (204-2) and an intermediate lift position (204-1). 23. The control unit (300) of clause 22, wherein the control unit (300), in the intermediate lift position (204-1) of the spool (402), is configured to cause the primary pump (118) to supply the hydraulic fluid at a first flow rate to the head side (404) of the ram assembly (110), wherein the first flow rate is determined based on the position of the spool (402). 24. The control unit (300) of clause 21, wherein the control unit (300), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1), is configured to perform the lowering motion of the ram assembly (110). 25. The control unit (300) of clause 21, wherein the control unit (300) is configured to one of directly and indirectly send a control signal to the control valve (122), wherein the control valve (122) is one of a counter-balance valve (420) and a hose burst valve (422). 26. The control unit (300) of clause 25, wherein the control unit (300), in response to determining that the spool (116) is in one of a full drop position (202-2) and an intermediate drop position (202-1), is configured to transmit the control signal to an electro-proportional control valve (EPCV) (120), wherein the EPCV in response to the control signal is to send a pilot signal to the counter-balance valve (420) for regulating an opening of the counter-balance valve (420), wherein by regulating the control unit (300) regulates an extent of the opening of the counter-balance valve (420). 27. The control unit (300) of clause 25, wherein the control unit (300) is configured to: establish, based on a position signal received from the sensor (116), a rate of change of position of the spool (402); and control speed of opening of the counter-balance valve (420) as a function of the rate of change of position of the spool (402). 28. The control unit (300) of clause 21, wherein the control unit (300) is configured to control speed of movement of the ram assembly (110) as a function of position of the spool (402). 29. The control unit (300) of clause 25, wherein the control unit (300) is configured to restrict a speed of opening of the counter-balance valve (420) upon establishing, that a rate of change in position of the spool (402) has exceeded a pre-defined threshold rate of change of position. 30. The control unit (300) of clause 25, wherein the control unit (300) is configured to one of directly and indirectly send the control signal to the counter-balance valve (420), wherein the control signal corresponds to conditions of a hydraulic hose, wherein the counter-balance valve (420) is to perform functions of a hose burst valve to stop the flow of hydraulic fluid in response to determining the condition of bursting of a hydraulic hose in a hydraulic circuit. 31. A method (500) to regulate movement of a ram assembly (110) of a controlled actuation system (100), the controlled actuation system (100) comprising a sensor (116), a primary pump (118), and a control valve (122), wherein the method comprises: determining (502), from the sensor (116), a position of a spool (402) of a mechanical valve (114), wherein the spool (402) is movable in the mechanical valve (114) to control flow of a hydraulic fluid through the mechanical valve (114), wherein the position of the spool (402) is controllable by a hand lever (112); causing (504), in response to determining that the spool (402) is in a lift position (204), the primary pump (118) to supply the hydraulic fluid, through the mechanical valve (114), to a head side (404) of the ram assembly (110) for the ram assembly (110) to exhibit a lifting motion; and causing (506), in response to determining that the spool (402) is in a drop position (202), the primary pump (118) to supply the hydraulic fluid through the mechanical valve (114) and the control valve (122), to a rod side (400) of the ram assembly (110) for the ram assembly (110) to exhibit a lowering motion, wherein the causing (506) comprises controlling the control valve (122) to regulate the supply of the hydraulic fluid to the rod side (400) of the ram assembly (110). 32. The method (500) of clause 31, wherein exhibiting (504) the lifting motion of the ram assembly (110) is in response to determining that the spool (402) is in one of a full lift position (204-2) and an intermediate lift position (204-1). 33. The method (500) of clause 31, wherein exhibiting (506) the lowering motion of the ram assembly (110) is in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1). 34. The method (500) of clause 31, wherein exhibiting (506) the lowering motion comprises supplying, the hydraulic fluid at a first flow rate to the head side (404) of the ram assembly (110), in response to determining that position of the spool (402) is in an intermediate drop position (202-1), wherein the first flow rate is determined based on the position of the spool (402). 35. The method (500) of clause 31, wherein exhibiting (506) the lowering motion, comprises sending one of directly and indirectly a control signal to the control valve (122), the control valve (122) being one of: a counter-balance valve (420) and a hose burst valve (422). 36. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises transmitting, the control signal to an electro-proportional control valve (EPCV) (120), wherein the EPCV (120) in response to the control signal is to send a pilot signal to the counter-balance valve (420) for regulating an extent of an opening of the counter-balance valve (420). 37. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises transmitting flow of the hydraulic fluid to an EPCV (120) through a shuttle valve (418), wherein the shuttle valve (418) is to control flow of the hydraulic fluid to the EPCV (120) from at least one of the primary pump (118) and a secondary pump (408), wherein the shuttle valve (418) is to allow flow of the hydraulic fluid to the EPCV (120) having a higher pressure between the hydraulic fluid from the primary pump (118) and the hydraulic fluid from the secondary pump (408). 38. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises controlling operation of the counter-balance valve (420) through an EPCV (120). 39. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises performing the lowering motion of the ram assembly (110) when the spool (402) is moved to one of a full drop position (202-2) and an intermediate drop position (202-1), wherein in an intermediate drop position (202-1) of the spool (402), controlling an opening of the counter-balance valve (420) in correspondence to the intermediate drop position (202-1) of the spool (402) and with the spool (402) in a full drop position (202-2), to completely open the counter-balance valve (420), wherein the opening of the counter-balance valve (420) is a function of the position of the spool (402) in one of the full drop position (202-2) and the intermediate drop position (202-1) and the opening of the counter-balance valve (420) is less than an opening of the spool (402). 40. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises establishing, based on a position signal received from the sensor (116), a rate of change of position of the spool (402), and controlling speed of an opening of the counter-balance valve (420) as a function of the rate of change of position of the spool (402). 41. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises controlling speed of movement of the ram assembly (110) as a function of position of the spool (402). 42. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprises restricting a speed of an opening of the counter-balance valve (420) upon establishing, that a rate of change in position of the spool (402) has exceeded a predefined threshold rate of change of position. 43. The method (500) of clause 35, wherein exhibiting (506) the lowering motion comprising sending the control signal to one of directly and indirectly to the counter-balance valve (420), wherein the control signal corresponds to conditions of a hydraulic hose, wherein the counter-balance valve (420) is to perform functions of a hose burst valve to stop the flow of hydraulic fluid in response to determining the condition of bursting of a hydraulic hose in a hydraulic circuit.

Claims

1. A controlled actuation system (100) for a working machine (102), the controlled actuation system (100) comprising:a ram assembly (110) having a fluid-actuated plunger (406) movably disposed therein, the ram assembly (110) divided into a head side (404) and a rod side (400) by the fluid-actuated plunger (406), wherein the fluid-actuated plunger (406) has a rod (414) connected to a load for actuating the load;a mechanical valve (114) hydraulically coupled to the ram assembly (110), the mechanical valve (114) having a spool (402) movable therein to control flow of a hydraulic fluid through the mechanical valve (114), wherein movement of the spool (402) is controllable by a hand lever (112);a sensor (116) to monitor a position of the spool (402) in the mechanical valve (114);a control valve (122) hydraulically coupled to the fluid-actuated plunger (406), wherein the control valve (122) is controllable to control flow of the hydraulic fluid to one of the head side (404) and the rod side (400) to regulate the movement thereof;a primary pump (118) hydraulically coupled to the mechanical valve (114), the control valve (122) and the ram assembly (110) to form a hydraulic circuit, wherein the primary pump (118) is configured to provide a flow of the hydraulic fluid in the hydraulic circuit of the controlled actuation system (100); anda control unit (300) operably coupled to the sensor (116) to receive at least a position signal corresponding to the position of the spool (402) of the mechanical valve (114), wherein the control unit (300) is configured to control at least one of the primary pump (118) and the control valve (122), based on the position signal, to regulate the flow of the hydraulic fluid to at least one of the head side (404) and the rod side (400) of the ram assembly (110) for regulating the movement of the fluid-actuated plunger (406).

2. The controlled actuation system (100) as claimed in claim 1, wherein the control unit (300) is configured to perform a lifting motion of the ram assembly (110), in response to determining that the spool (402) is in one of a full lift position (204-2) and an intermediate lift position (204-1), by causing supply of the hydraulic fluid, through the mechanical valve (114), to the head side (404) of the ram assembly (110) for the ram assembly (110) to exhibit the lifting motion.

3. The controlled actuation system (100) as claimed in claim 2, wherein the control unit (300), in the intermediate lift position (204-1) of the spool (402), is configured to cause the primary pump (118) to supply the hydraulic fluid at a first flow rate to the head side (404) of the ram assembly (110), wherein the first flow rate is determined based on the position of the spool (402).

4. The controlled actuation system (100) as claimed in claim 1, wherein the control valve (122) is a counter-balance valve (420).

5. The controlled actuation system (100) as claimed in claim 4, wherein the control unit (300) is configured to perform a lowering motion of the ram assembly (110), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1), by causing supply of the hydraulic fluid through the mechanical valve (114) and the counter-balance valve (420), to the rod side (400) of the ram assembly (110) for the ram assembly (110) to exhibit the lowering motion.

6. The controlled actuation system (100) as claimed in either of claims 4 or 5, wherein the control unit (300) is configured to control the counter-balance valve (420) to regulate supply of the hydraulic fluid to the rod side (400) of the ram assembly (110), in response to determining that the spool (402) isin one of a full drop position (202-2) and an intermediate drop position (202-1).

7. The controlled actuation system (100) as claimed in any of claims 4 to 6, comprising an electro-proportional control valve (EPCV) (120) hydraulically coupled to the counter-balance valve (420), wherein the EPCV (120) is operably coupled to the control unit (300) and is controllable to hydraulically regulate an operation of the counter-balance valve (420).

8. The controlled actuation system (100) as claimed in claim 7, the control unit (300), in response to determining that the spool (402) is in one of a full drop position (202-2) and an intermediate drop position (202-1), is configured to send a control signal to the EPCV (120), wherein, in response to the control signal, the EPCV (120) sends a pilot signal to the counter-balance valve (420) for regulating an opening of the counter-balance valve (420).

9. The controlled actuation system (100) as claimed in claim 8, comprising: a secondary pump (408) to provide hydraulic fluid to the EPCV (120), wherein the secondary pump (408) is controllable by the control unit (300) to provide the flow of the hydraulic fluid to the EPCV (120); anda shuttle valve (418) to control flow of the hydraulic fluid to the EPCV (120) from at least one of the primary pump (118) and the secondary pump (408), wherein the shuttle valve (418) is to allow the flow of the hydraulic fluid to the EPCV (120) having a higher pressure between the hydraulic fluid from the primary pump (118) and the hydraulic fluid from the secondary pump (408).

10. The controlled actuation system (100) as claimed in claim 8, wherein the opening of the counter-balance valve (420) is a function of the position of the spool (402) in the full drop position (202-2), wherein, optionally, the opening of the counter-balance valve (420) is less than an opening of thespool (402) in the full drop position (202-2) and / or wherein the opening of the counter-balance valve (420) is a function of the position of the spool (402) in the intermediate drop position (202-1), wherein optionally, the opening of the counter-balance valve (420) is less than an opening of the spool (402) in the intermediate drop position (202-1).

11. The controlled actuation system (100) as claimed in claim 8, wherein the opening of the counter-balance valve (420) is to create a flow path between the head side (404) and rod side (400) of the ram assembly (110) and to create a return flow path from the head side (404) to a fluid reservoir (416), wherein, optionally, the opening of the counter-balance valve (420), during execution of a lowering motion of the ram assembly (110), is to cause excess hydraulic fluid from the head side (404) of the ram assembly (110) to be directed to a fluid reservoir (416) through the counter-balance valve (420).

12. The controlled actuation system (100) as claimed in claim 4, wherein the control unit (300) is configured to:establish, based on the position signal received from the sensor (116), a rate of change of position of the spool (402), andcontrol a speed of opening of the counter-balance valve (420) as a function of the rate of change of position of the spool (402) and, optionally, the control unit (300) is configured to restrict the speed of opening of the counter-balance valve (420) upon establishing that a rate of change in position of the spool (402) has exceeded a pre-defined threshold rate of change of position.

13. The controlled actuation system (100) as claimed in any preceding claim, wherein the counter-balance valve (420) is to perform function of a hose burst valve (422) to stop the flow of hydraulic fluid in response to determining a condition of bursting of a hydraulic hose in the hydraulic circuit.

14. The controlled actuation system (100) as claimed in claim 1, wherein the control valve (122) is a hose burst valve (422), wherein the hose burst valve (422) is to stop the flow of hydraulic fluid in response to determining a condition of bursting of a hydraulic hose in the hydraulic circuit.

15. A control unit (300) for a controlled actuation system (100) of a working machine (102), the control unit (300) being coupled to a sensor (116), a primary pump (118), and a control valve (122) to regulate movement of a ram assembly (110) of the controlled actuation system (100), wherein the control unit (300) is configured to:determine, from the sensor (116), a position of a spool (402) of a mechanical valve (114), wherein the spool (402) is movable in the mechanical valve (114) to control flow of a hydraulic fluid through the mechanical valve (114), wherein the position of the spool (402) is controllable by a hand lever (112);cause, in response to determining that the spool (402) is in lift position (204), the primary pump (118) to supply the hydraulic fluid, through the mechanical valve (114), to a head side (404) of the ram assembly (110) for the ram assembly (110) to exhibit a lifting motion; andcause, in response to determining that the spool (402) is in drop position (202), the primary pump (118) to supply the hydraulic fluid through the mechanical valve (114) and the control valve (122), to a rod side (400) of the ram assembly (110) for the ram assembly (110) to exhibit a lowering motion, wherein, in the drop position (202) of the spool (402), the control unit (300) is configured to control the control valve (122) to regulate the supply of the hydraulic fluid to the rod side (400) of the ram assembly (110) to assist the ram assembly (110) in exhibiting the lowering motion.

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