Field of the Invention

The present invention relates to an apparatus with a hydraulic system. The present invention also relates to an apparatus with a hydraulic system which have the improved ride control system. More particularly, this present invention also relates to a method and apparatus having a dampening the shocks in a construction industry vehicle with front end loader.

Background of the invention

It is well known that when a machine, such as a wheel loader, backhoe loader, with a loaded/ unloaded bucket is driven there is always the possibility that the machine will lope or bounce due to the weight of the loaded/ unloaded bucket reacting to the machine encountering rough terrain or other obstacles. In order to help reduce or eliminate this lope or bounce it is know to use accumulators that are selectively connected to the lift actuators. With the accumulator connected to the loaded end of the lift actuator pressure fluctuations in the actuators is absorbed thus offsetting changing forces acting on the tires of the machine. It is the changing forces acting on the tires of the machine that produces the lope or bounce. In order to maintain a pre-charge in the accumulator equal to the pressure in the loaded end of the actuators, it is known to connect the accumulator, during normal use, to the loaded end of the lift actuators by connecting a conduit there between. The conduit normally has a valve, having an orifice, that is selectable moved to dispose the orifice within the conduit when the machine is not operating in the ride control mode. It has been found that during some situations that the pressure in the accumulator may not be equal to the pressure in the loaded end of the lift actuator when the ride control is activated. The pressure not being equalized could allow the load to "drop" slightly or "jump" thus adding to the problem of machine bounce or subjecting the machine to a "jolt" Furthermore, it has been found that in previous systems, the ride control is always functional, once activated, even though operating conditions would be better if the ride control were turned off.

Various types of off-road or construction vehicles are used to perform excavation functions such as leveling, digging, material handling, trenching, plowing, etc. These operations are typically accomplished with the use of a hydraulically operated bucket, backhoe or other implement. These implements include a plurality of linkages translationally supported and rotationally supported, and are moved relative to the supports by hydraulic cylinders or motors. As a result of the type of work these machines are used to perform (i.e. job site work) these machines are often required to travel on roads between job sites. Accordingly, it is important that the vehicle travel at reasonably high speeds. However, due to overhang of the implements supported on the vehicle, vehicle bouncing, pitching or oscillation occurs at speeds satisfactory for road travel.

It is well known that when a machine, such as, for example, a wheel loader, is being driven for a distance with a loaded/unloaded bucket there is always the possibility that the machine will be subjected to shocks due to the weight of the loaded bucket reacting to the machine encountering bumps or other obstacles in its pathway. In order to help reduce or eliminate shocks, it is known to use accumulators that are selectively connected to the lift cylinder actuator. These accumulators, when connected to the loaded end of the actuators, serve to absorb the pressure fluctuations in the actuators thus offsetting the changing forces that would otherwise be acting on the various components of the machine. It is these changing forces acting on the machine that produces the shocks. In order to maintain a pre-charge in the accumulator equal to the pressure in the loaded end of the actuators, it is known to connect the accumulator, during normal use, to the loaded end of the lift cylinder actuator. This is normally accomplished by connecting a conduit therebetween. The conduit normally has an orifice therein that is selectively disposed in the conduit when the machine is not operating in the ride control mode. When the ride control system is active, the load supporting end of the cylinder is in free communication with the accumulator in order to absorb the changing forces. It has been found in at least some situations that the degree of damping during ride control should be varied based on the magnitude of the shock to the machine.

The document JP2000-309953 describes the suppressing of these vibrations, a bottom pressure chamber of a boom cylinder and an accumulator are brought into communication with each other during traveling to have pressure fluctuations in the bottom pressure chamber absorbed in the accumulator, and during digging work with a bucket, on the other hand, the communication with the accumulator is cut off to prevent the absorption of digging force in the accumulator. As a conventional technique of this sort, reference can be made to.
The other document DE102009003472 states that the closed ride level control system for vehicles, through which a vehicle body relative to at least one vehicle axle is sprung, containing the following ingredients:-pressure medium chambers , which branches with a pressure medium line , respectively, - a compressor , - an air dryer which is arranged in a pressure medium line, - a pressure fluid supply reservoir via the compressor with the pressure medium chambers being in communication - that pressure medium from the pressure fluid reservoir via the compressor into each pressure medium chamber can be transferred, said compressor input then over a with a directional control valve through-connected pressure medium line with the pressure fluid reservoir and the compressor output then over a with a directional control valve.

According to the document KR20110008946, an electro-hydraulic ride control system for construction equipment is provided to easily offset vibration pressure generated in a boom cylinder. An electro-hydraulic ride control system for construction equipment comprises a hydraulic boom cylinder, a driving unit, a hydraulic line, an accumulator, a main bidirectional electro-hydraulic poppet valve, and a pressure control module. The hydraulic boom cylinder, comprising a head and a rod connected to the head, raises and lowers a bucket of construction equipment. The driving unit is connected to the head and the rod of the boom cylinder and provides hydraulic fluid of fixed pressure to the boom cylinder. The hydraulic line is connected to a head side first driving line of the boom cylinder. The accumulator is installed on an end of the hydraulic line. The main bidirectional electro-hydraulic poppet valve is installed in the hydraulic line. The pressure control module controls the opening/closing of the hydraulic line using the main bidirectional electro-hydraulic poppet valve in order to maintain the set pressure at the head side and the rod side of the boom cylinder.

The document WO2006130282 describes the hydraulic control system for a work machine is disclosed. The hydraulic control system has a source of pressurized fluid and at least one actuator having a first and a second chamber. The hydraulic control system also has a first independent metering valve disposed between the source and the first chamber, and a second independent metering valve disposed between the reservoir and the second chamber. The first and second independent metering valves each have a valve element movable between a flow blocking and a flow passing position to facilitate movement of the at least one actuator. The hydraulic control system further has an accumulator and a third independent metering valve disposed between the source and the first independent metering valve. The third independent metering valve is configured to selectively communicate the accumulator with the first chamber to cushion movement of the at least one actuator.

The other document CN1776123 discloses the invention which describes a hydraulic ride control system for a working vehicle such as a wheel loader is provided with boom cylinders, an actuator control valve for controlling a pressure in bottom pressure chambers of the boom cylinders, an accumulator connected to the bottom pressure chambers of the boom cylinders via a connection line, an opening control valve having a pilot chamber to selectively communicating or cutting off the connection line depending on a pressure in the pilot chamber, and a selector unit for selectively feeding a pressure to or draining a pressure from the pilot chamber. The selector unit comprises a controller for variably controlling an opening of the opening control valve.

The invention which is described in the document JP2001200801 to provide a hydraulic ride quality control system of a machine, particularly, a control system selectively preparing a damping ride quality control. This hydraulic ride quality control system controls the ride quality of a machine having a load thereon. A ride quality control includes an accumulator device connected selectively to an actuator supporting the load, prepares a damping ride quality during running and, when raising the load, allows a pressure in the accumulator device to be maintained to be substantially equal to a pressure in the actuator. When the load is reduced, a pressure in the accumulator is allowed to be reduced to a pressure in the actuator. Also, the ride quality control system always prepares a device to allow the accumulator device to be depressurized when the machine is stopped or if the machine lost its function.

Another document US 5,473,990 states that a ride vehicle for used in an amusement attraction. The ride vehicle mounts a structure upon a hydraulically-actuated motion base, so that the passenger holding structure may be articulated about one or more axes as the vehicle moves. Thus, this "simulator ride" carries passengers through three-dimensional scenery and articulates the passenger holding structure in synchronism with motions of the ride vehicle, the motions of moving show sets, which are external to the vehicle, sound, projection and other effects. The ride vehicle is programmably-controlled, and derives electrical power from a track mounted power bus to drive vehicle hydraulics, which drive motion base actuation, steering and vehicle velocity. The hydraulic control system uses an electric pump to charge a high-pressure accumulator with hydraulic power from a 480-volt power supply, a manifold to regulate the supply of hydraulic energy to motion base and steering actuators and a hydraulic motor, and a low-pressure accumulator that aids in regenerative braking. Using these elements, the computerized vehicle-control system controls the hydraulically-actuated elements to provide synchronized motions of the vehicle and passenger holding structure, and other special effects, in accordance with a selected one of a plurality of ride programs.
As is known well, the ride control system is used to dampen shocks due to weight overhang of front bucket by absorbing the pressure shocks in an accumulator.
In the known damping system, the shocks are absorbed in the accumulator after manual switching 'ON' the valves to direct the oil path to accumulator during travelling or the mechanism is based on speed sensing that means the Ride Control System gets switched automatically 'ON' if the speed of vehicle exceeds the normal working speed. The ride control system remains inactive below that speed.
The main disadvantage of the above systems is that either the system is operator dependent or it remains inactive at low speeds even if the vehicle is travelling. The operator can still experience shocks if vehicle is moving at slow speeds and travelling through rough terrains, or speed breakers.

To solve this problem, an automatic system has been developed which senses the pressure in the hydraulic circuit to electrically disconnect the accumulator from the hydraulic circuit.

None of these above patents, however alone or in combination, disclose the present invention.

Summary of the invention

Accordingly an object of the present invention relates to an apparatus with a hydraulic system. The present invention also relates to an apparatus with a hydraulic system having improved ride control system. More particularly, this present invention also relates to a method and apparatus for dampening the shocks in a construction industry vehicle with front end loader.
BRIEF DESCRIPTION OF DRAWINGS:
Fig 1 and 2 shows the working of the ride control system;
Fig 3 and 4 shows the position of pressure switch,
Fig 5 shows switches off the solenoids,

Detailed description of the invention with accompanying drawings

There are many possible embodiments of this invention. The drawings and description below describe in detail a preferred embodiment of the invention. It should be understood that the present disclosure is to be considered of the present invention.

The principal object of the invention is to provide an apparatus with a hydraulic system.

The other embodiment of the invention is to provide an apparatus with a hydraulic system which have the improved ride control system.

The other embodiment of the invention is to provide a method and apparatus having for dampening the shocks in a construction industry vehicle with front end loader.

The other embodiment of the invention is that when the loader of a machine is not being operated, the pressure in the hydraulic circuit will be low as the oil from the pump is dumped to sump in neutral. When any hydraulic function is operated, the pressure immediately shoots up. This pressure jump can be recorded by using a pressure switch which switches ON above the reset pressure.

The advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjugation with accompanying drawings and these drawings are illustrative in explaining the constructional details of the apparatus of the invention. Such drawings are shown in five sheets.

The above diagram shows the working of the ride control system. When the ride control system solenoids, S1 and S2, are switched ON, the piston end of the lift ram gets connected to the accumulator through the spool connected to solenoid S1 and the rod end of the lift ram gets connected to the tank through the spool connected to solenoid S2 as shown in the diagram. These connections facilitate absorption of shocks inside the accumulator as the oil present in the piston end is free to move the accumulator membrane up and down in the absence of pressure from the rod end. When the solenoids are switched off, the accumulator and tank line are cut-off from the system and the Ride Control System stops working.
The invention may be better understood by referring to the following detailed description, which should be read in conjunction with the accompanying drawings. The detailed description of a particular preferred embodiment, set out below to enable one to build and use one particular implementation of the invention.

In the current invention it is important that the Ride Control System remain inactive during normal working applications such as loading and dozing.
The switching of the Ride Control System can be achieved by many means, for example, based on speed or manually.
This draft proposes an automatic method which switches 'ON' the Ride Control System whenever required without any human intervention at all speeds. This system uses a pressure switch to determine the state of Ride Control System (Fig 1).

When the loader of a machine is not being operated, the pressure in the hydraulic circuit will be low as the oil from the pump is dumped to sump in neutral. When any hydraulic function is operated, the pressure immediately shoots up. This pressure jump can be recorded by using a pressure switch which switches ON above the reset pressure. Operating the loader lever will cause the pressure in the system to rise due to large amount on resistance encountered to the flow of hydraulic oil and this rise in pressure will be registered by the pressure switch which would switch OFF the solenoids present in the ride control system and disconnect the accumulator out of the hydraulic circuit.

The diagram as shown in figures 2 and 3, the position of pressure switch which has been placed very near to the source of hydraulic oil in the hydraulic circuit. This position ensures that the Ride Control System is switched 'OFF' even when oil is entering the ram at rod end at high pressure and exiting the piston end at low pressure, hence bringing the loader arm down ( Fig 2 and 3).
The electrical circuit diagram shown above switches off the solenoids, S1 and S2 are present in the ride control system to disable it so that the hydraulic operations of the machine can occur properly.

From the foregoing, it will be observed that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present control system. It will be appreciated that the present disclosure is intended as an exemplification of the control system, and is not intended to limit the control system to the specific embodiment illustrated. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.

CLAIMS:

1.A method for dampening shocks in a vehicle comprising :
? At least one primary pump unit for pumping hydraulic fluid from a hydraulic reservoir (1) and deliver it to a hydraulic fluid pressure line;
? At least one hydraulic fluid pressure sensing unit (4) mounted on hydraulic fluid pressure line;
? At least one solenoid valve (5 & 6) which receive the signals from the electronic control unit (1);
? At least one hydraulic fluid pressure control valve (2) for controlling the hydraulic fluid circulation;
? At least one accumulator (7) connected to the either of solenoid valve (5 or 6); and
? At least one work hydraulic cylinder (10) used for various work operations.

2. The method for dampening shocks in a vehicle claimed in claim 1, wherein the hydraulic fluid pressure detected by sensing unit (4) is more than a pre-determined hydraulic pressure then the either or both solenoid valve (5 & 6) get close which further stop the hydraulic fluid flow to the accumulator (7).

3. The method for dampening shocks in a vehicle claimed in claim 1, wherein the hydraulic fluid pressure detected by sensing unit (4) is less than a pre-determined hydraulic pressure then the either or both solenoid valve (5 & 6) get open which further allow the hydraulic fluid flow to the accumulator (7).

4. The method for dampening shocks in a vehicle comprising :
? At least one primary pump unit for pumping hydraulic fluid from a hydraulic reservoir (1) and deliver it to a hydraulic fluid pressure line;
? At least one position sensing unit (4) mounted below a loader arm lever;
? At least one solenoid valve (5 & 6) which receive the signals from the electronic control unit (1);
? At least one hydraulic fluid pressure control valve (2) for controlling the hydraulic fluid circulation;
? At least one accumulator (7) connected to the either of solenoid valve (5 or 6); and
? At least one work hydraulic cylinder (10) used for various work operations.

5. The method for dampening shocks in a vehicle claimed in claim 4, wherein the sensing unit (4) detects movement of the loader arm lever then the either or both solenoid valve (5 & 6) get close which further stop the hydraulic fluid flow to the accumulator (7).

6. The method for dampening shocks in a vehicle claimed in claim 4, wherein the sensing unit (4) detects no movement of the loader arm lever then the either or both solenoid valve (5 & 6) get open which further allow the hydraulic fluid flow to the accumulator (7).

7. The method for dampening shocks in a vehicle comprising :
? At least one primary pump unit for pumping hydraulic fluid from a hydraulic reservoir (1) and deliver it to a hydraulic fluid pressure line;
? At least sensing unit (4) to measure electrical or mechanical input or combination of both;
? At least one solenoid valve (5 & 6) which receive the signals from the electronic control unit (1);
? At least one hydraulic fluid pressure control valve (2) for controlling the hydraulic fluid circulation;
? At least one accumulator (7) connected to the either of solenoid valve (5 or 6); and
? At least one work hydraulic cylinder (10) used for various work operations.

8. The method for dampening shocks in a vehicle claimed in claim 7, wherein the sensing unit (4) detect the electrical or mechanical input or combination of both then the either or both solenoid valve (5 & 6) get close which further stop the hydraulic fluid flow to the accumulator (7).

9. The method for dampening shocks in a vehicle claimed in claim 7, wherein the sensing unit (4) detect no the electrical or mechanical input or combination of both then the either or both solenoid valve (5 & 6) get close which further stop the hydraulic fluid flow to the accumulator (7).

10. The method for dampening shocks in a vehicle claimed in any of preceding claims, wherein the either or both solenoid valve (5 & 6) may be controlled by at least one electronic control unit which takes inputs form the sensing unit (4).