DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
EMERGENCY BLADE LOWERING SYSTEM

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru,
Karnataka - 560 027, India

The following specification particularly describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority to Indian Patent Application No. 201841035168, titled “EMERGENCY BLADE LOWERING SYSTEM” filed on September 18th, 2018, the entirety of which is hereby incorporated by reference.
TECHNICAL FIELD
[002] The present invention relates to the field of heavy machinery, and more particularly, the present invention relates to an emergency blade lowering system using the available stored energy of blade lift cylinder.
BACKGROUND
[003] Generally, the dozer hydraulic system consist of hydraulic oil reservoir (tank), gear pumps to discharge oil flow, direction control valve for oil flow path control, hydraulic cylinders for movement of blade, pilot oil control system for actuation of control valve spools and pipes & hoses for conducting of oil flow path connections.

[004] The power train system of dozer consists of Engine, Power Take Off (PTO), Torque converter, Transmission and Final drive with Brake system. Hydraulic cylinders to lift and lower and tilt up/down of the dozer blade attachment. The dozer equipment works in very steep gradients in the field. When working in gradients due to inertia of the equipment & it tends to move along the down gradient. To control this movement of equipment operator has to use service brake to stop the machine when engine is running. If engine stops, the service brakes are not efficient and effective. In case of service brake failure, operator can stop the machine by lowering the dozer blade and pressing it against ground.

SUMMARY
[005] Before the emergency blade lowering system and method using the available stored energy of blade lift cylinder, are described, it is to be understood that this application is not limited to the particular methodologies described, as there can be multiple possible embodiments, which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations, versions, or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an emergency blade lowering system and method using the available stored energy of blade lift cylinder. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[006] In one embodiment, a system and method for emergency blade lowering system is disclosed that utilises the available stored energy of blade lift cylinder. In the system, a reducer valve is connected to a cylinder rod end. The reducer valve reduces a lower backup line pressure with respect to a pilot line pressure to maintain a backup system. The relief valve maintains the pilot line pressure. A reduced backup line pressure is given as backup to a shuttle valve and facilitates priority flow for a joystick (9) operation. A check valve holds the joystick line pressure and isolates a pump pressure.
BRIEF DESCRIPTION OF DRAWINGS
[007] The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating of the present subject matter, an example of construction of the present subject matter is provided as figures; however, the present subject matter is not limited to the specific method disclosed in the document and the figures.
[008] The present subject matter is described detail with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer various features of the present subject matter.
[009] Figure 1 illustrates the control block for emergency blade lowering system using the available stored energy of blade lift cylinder.
[0010] Figure 2 illustrates method for emergency blade lowering using the available stored energy of blade lift cylinder, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[0011] Some embodiment of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising”, “having”, “containing” and “including”, and “including” and other forms thereof, are intended to be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although an emergency blade lowering system and method using the available stored energy of blade lift cylinder , similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, an emergency blade lowering system and method using the available stored energy of blade lift cylinder are now described.

[0012] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments for an emergency blade lowering system and method using the available stored energy of blade lift cylinder. However, one of ordinary skill in the art will readily recognize that the present disclosure for an emergency blade lowering system and method using the available stored energy of blade lift cylinder is not intended to be limited to the embodiments described, but is to be accorded the widest scope consistent with the principles and features described herein.

[0013] In dozers working in steep gradient field, blade lowering can be done through operating the blade lower spool of main control valve by means of pilot oil control. In case of emergency switching off the engine pilot oil supply pump will not give pressure oil for actuation of spool by pilot joystick. Due to this the blade lowering operation cannot be performed and stopping of equipment by pressing blade against ground is not possible leading to fatal accidents. To prevent this type of failures accumulator backup system is provided in pilot circuit. During normal operation accumulator inside bladder contained Nitrogen gas is compressed and stores hydraulic oil pressure energy. During Emergency switching off engine, this will serve as backup system for pilot joystick operation. Thus, blade lowering function can be performed to stop the machine. With the above system the equipment braking can be achieved to avoid fatal accidents. But in some cases, failure of above systems will lead to fatal accidents due to gas leaks in accumulator and it is very alarming thing and the control of such events is prime most important.
[0014] The system here discloses a system for emergency blade lowering in condition when the existing system fails due to switch off or accumulator malfunction. The system utilises hydraulic energy stored in blade lifted cylinder rod end oil to stop the dozer by lowering the blade to ground. The system is efficient and ensures lowering of blade in emergency condition to avoid fatal accidents.
[0015] Now Referring to figures, Figure 1, represents pilot control and emergency blade lowering system. The pilot control system consists of the following components.
Pilot logic control block (01) Accumulator (02) Shut off valve (03)
Relief valve (04) Directioncontrol valve/check valve (05) Shuttle valve (06)
Reducing valve (07) adapter plate (08)
[0016] The components of blade lowering are integrated into a compact system in the pilot logic control block (1)
[0017] The figure 1 illustrates pilot control block (01), that integrates the features of blade lowering system for emergency blade lowering system. The logic control block comprises accumulator (02), shut off valve (03), Relief valve (04), one-way direction control valve / check valve (05), shuttle valve (06), reducing valve (07), adapter plate (08) and pressure measuring point M.In the logic control block (01), the reducer valve (07) placed on an adapter plate (08) is connected to cylinder rod end (C) line through a 3mm diameter port. This connection helps maintain the backup line pressure lower with respect to pilot line pressure. A shuttle valve (06) connected to the reducer valve (07) and the shuttle valve (06) facilitates priority flow for the joystick operation. Check valve (05) is connected to the shuttle valve (06). The Check valve (05) holds the joystick line pressure and isolates the pilot pump line pressure. A relief valve (06) connected to the reducer valve maintains the pilot line pressure to the required limit. Further M represents the pressure measuring point connected to the shuttle valve (06). An accumulator is connected to connection between shuttle valve (06) and check valve (05).
[0018] Figure 2 illustrates steps involved in method for emergency blade lowering system that uses available stored energy of blade lift cylinder.
[0019] Step 1 of the methodinvolves the hydraulic dozer with pilot operation control system and the dozer blade upward and downward movement of the dozer blade are carried out through hydraulic cylinders. During upward operation of the dozer blade the pressure energy is stored in rod side of cylinder due to force produced from blade and side frame mass. The pressure energy stored is available all the time in cylinder as long as the blade is in upward position. This available pressure energy can be tapped from cylinder and used as backup energy system to control pilot operation of main control valve spool. When the control valve spool is actuated to lowering position, blade will lower down by virtue of gravity force.
[0020] In Step 2, the stored pressure of hydraulic oil trapped from 3mm diameter port in hydraulic cylinder rod end line is passed through button filter in order to remove contamination generated from hydraulic cylinder or other hydraulic parts, in order to have a trouble-free operation of hydraulic implements.
[0021] Further in Step 3, the stored pressure energy of hydraulic oil is at higher pressure to pilot line pressure generated from pilot pump system. Backup line pressure is maintained at lower with respect to pilot line pressure in order have a backup system. The lower pressure is maintained by tapping a connection from 3mm diameter port from cylinder rod end line to reducer valve, where hydraulic oil pressure reduces to 22 bar from system pressure and given backup to shuttle valve. There by always a backup line pressure is available to the pilot logic control block as a additional safety. To maintain the pilot line pressure to the required limit, it is always necessary to have a relief valve in the pilot logic control block. The shuttle valve is required in the system to facilitate priority flow to the joystick operation. In order to hold the joystick line pressure and to isolate the pilot pump / Running line pressure a one way non return line type check valve used in the pilot logic control block during engine off condition.
[0022] Subsequent to step 3, at Step4. PPC / logic valves/ joystick is a proportional pressure reducing valve is used to control implement operations of hydraulic dozer. It is a feather touch control system device by means of which the operator can control all the operations of the implements like blade up/lower and blade tiltfrom the cabin. The joy stick controls the pilot operations of main control valve for all the implement operation. The pressure energy source for joystick operation are taken from pilot pump system, accumulator backup and also from cylinder line stored energy for hazard free equipment operations.

[0023] At Step 5, the main control valve is pilot operated type direction control valve which controls the direction of flow to the respective implement’s operation. By actuating the feather touch joy stick, the respective operations of the implements are controlled.

[0024] Finally, at Step 6, the operations of the main control valve is controlled through feather touch joy stick control system. The three system back up for pressure energy from pilot pump, accumulator backup and also from hydraulic cylinder stored energy the blade lowering operation can be controlled. During failure of pilot pump, accumulator backup system the stored pressure energy from hydraulic cylinder is used in order to have emergency braking system by lowering blade and pressing blade against ground.
,CLAIMS:
1. An emergency blade lowering system for a field vehicle, the emergency blade lowering system comprises;
a reducer valve (07), wherein a connection is established from a cylinder rod end (C) to the reducer valve (07), and wherein the connection reduces a lower backup line pressure with respect to a pilot line pressure to maintain a backup system, and wherein a relief valve (04) maintains a pilot line pressure;
a shuttle valve (06), wherein a reduced backup line pressure is given as backup to the shuttle valve, and wherein the shuttle valve facilitates priority flow for a joystick (09) operation; and
a check valve (05), wherein the check valve holds the joystick (09) line pressure and isolates a pilot pump pressure.
2. The emergency blade lowering system as claimed in claim 1, wherein a blade lowering feature integrated to a compact system in the pilot logic control block (01).

3. The emergency blade lowering system as claimed in claim 1, wherein a hydraulic cylinder lifts and lowersa dozer blade and wherein an energy is stored in a rod side of a cylinder.

4. The emergency blade lowering system as claimed in claim 1, wherein an available pressure energy can be tapped from the cylinder and used as a backup energy system to control a pilot operation of a main control valve spool.

5. The emergency blade lowering system as claimed in claim 1, wherein a stored pressure energy of a hydraulic oil tapped from the hydraulic cylinder rod end line is passed through a button filter to remove contamination.

6. The emergency blade lowering system as claimed in claim 1, wherein the joystick (9) controls a pilot operations of a main control valve.

7. The emergency blade lowering system as claimed in claim 1, wherein the joystick (09) acquires a pressure energy from a pilot pump system, an accumulator (02) backup and also from a cylinder line stored energy.

8. The emergency blade lowering system as claimed in claim 1, wherein the main control valve is a pilot operated type direction control valve which controls a direction of flow to a respective implements operation.

9. The emergency blade lowering system as claimed in claim 1, wherein during failure of the pilot pump and the accumulator (02) backup system a stored pressure energy from a hydraulic cylinder is used to lower a blade.