DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
A HYDRAULIC ASSISTED STEERING AND BRAKING CONTROL SYSTEM FOR EASY OPERATION OF BULL DOZER
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
[001] The present invention relates to the field of bulldozer. The present invention in particular relates to a hydraulic assisted steering and braking control system for easy operation of bull dozer.
DESCRIPTION OF THE RELATED ART:
[002] The traditional bulldozer steering brake control mainly controls the steering brake valve through the pilot valve handle, and then controls the corresponding steering clutch and brake to realize the steering.
[003] The pilot valve handle is used as the pilot of the steering brake valve. Only when the steering stroke of the pilot valve handle reaches a certain value, the output pressure of the pilot valve handle can drive the steering or brake spool, so that the steering clutch or brake builds pressure. Usually the pressure will jump, that is, it will rise directly from zero to a certain pressure, and then the pressure will rise slowly, but the brake only needs a small pressure, and the whole machine can realize unilateral braking. The pressure jump at the initial stage of pressure building has realized unilateral steering and the impact is large, the follow-up pressure control is of little significance, resulting in a very small effective controllable stroke of the steering brake and poor handling comfort.
[004] Reference may be made to the following:
[005] Publication No. CN102839701 relates to the field of machinery, in particular to a braking system of a bulldozer. The braking system comprises a steering clutch, a brake-type steering machine and a step less speed regulation hydraulic steering motor, wherein the steering clutch is connected with the brake-type steering machine, so that the pivot steering of a mechanism is realized, the radius of the steering range is small, and the steering is flexible; and the step less speed regulation hydraulic steering motor is connected with a speed-variable control lever, so that different steering radiuses and rotating speeds can be realized.
[006] Bulldozer braking system, characterized in that it includes a steering clutch, a brake-type steering gear and a steplessly adjustable hydraulic motor concept is different from present invention -
1. The Hydraulic assisted braking system added the additional hydraulic pressure to brake booster to apply the brake when operator operates the brake pedal and results effortless braking.
2. In steering operation additional pressure from steering circuit given for brake system, so that automatically brake will apply while operating the steering levers. This system avoids manual brake operations while steering.
[007] Patent No. US5503232 relates to a steering system for a bulldozer, comprising a steering direction indicating device for indicating a lateral direction in which a vehicle body is to be steered, a dozing operation detector for judging by detection whether the bulldozer is in dozing operation, a steering controller for controlling the vehicle body to be steered in the lateral direction indicated by the steering direction indicating device when the dozing operation detector judges that the bulldozer is in dozing operation, by tilting a blade in the indicated lateral direction in order to impose offset load on the vehicle body, and by causing a difference between the relative travel speeds of right and left crawler belts attached to the vehicle body at least when light load occurs in the dozing operation.
[008] This system is different from hydraulic assisted steering and braking control system for easy operation of conventional heavy bull dozer.
[009] Publication No. CN210174838 relates to a brake boosting oil cylinder. The power-assisted steering and braking oil cylinder comprises an oil cylinder body fixed to a vehicle, a piston assembly arranged in the oil cylinder body, and a shaft arranged in the piston assembly in a sliding mode. The second piston rod penetrates through the oil cylinder cover and is in sealed sliding fit with the oil cylinder cover; the first piston rod penetrates through the sealing plate and is in sliding fit with the sealing plate in a sealed mode, the two ends of the disc spring are connected to the sealing plate and the piston in a pressed mode respectively, a reset spring containing hole is formed in the right side end face of the shaft, and an oil drainage opening communicated with the right cavity and an inner cavity of the piston assembly is formed in the outer wall of the second piston rod.
[010] This system is of electro hydraulic type, and is different from hydraulic assisted steering and braking control system for easy operation of conventional bull dozer.
[011] Publication No. CN214657325 relates to a hydraulic control steering system for a bulldozer. The hydraulic control steering system comprises an oil tank, a steering pump, a steering overflow valve, a handle pilot valve, a steering valve, a steering clutch and a brake mechanism. The steering pump is connected with the steering valve through a main pipeline; an oil outlet pipeline of the steering valve is connected with a steering clutch; the steering pump is connected with a handle pilot valve through a branch pipeline, and the branch pipeline is provided with a steering overflow valve in a matched mode.
[012] This system is of pilot operated type whereas the present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[013] Publication No. CN104149849 relates to the technical field of hydraulic control components, in particular to a hydraulic steering brake system. Steering of a hydraulic control steering brake valve is controlled through a hydraulic pilot handle, a hydraulic pedal brake valve and a shuttle valve bank, the mode that steering of the steering brake is controlled through a mechanical connection rod and a flexible shaft is replaced, people only need to overcome resistance of the hydraulic pilot handle or a pedal of the hydraulic pedal brake valve during operation to achieve the work processes of sharp turning, little turning and emergent braking of a bulldozer, control force is obviously reduced, the operation comfort degree is improved, the structure is simple, installation space is saved, and time for debugging and installation is reduced.
[014] This system is of pilot operated type whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[015] Publication No. CN103863280 relates to a hydraulic control flexible steering brake system for a bulldozer. The hydraulic control flexible steering brake system for the bulldozer comprises a bevel gear, a transverse shaft, a steering clutch, a brake clutch and a brake pedal, wherein the brake pedal is connected with a connecting rod, the connecting rod is connected with a brake valve through a rocker arm, the brake valve is a stroke valve, and the brake valve is connected with a steering oil cavity of the steering clutch and a brake oil cavity of the brake clutch through an oil path in sequence according to the advancing path of a valve core of the brake valve. This is hydraulic control flexible steering brake system for bulldozer whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[016] Publication No. CN202345753 relates to a bulldozer steering and braking control system, belonging to the technical field of engineering machinery and aiming at improving the operation comfortableness of the bulldozer.
[017] Bulldozer steering and braking control system composed of four proportional solenoids, respectively a left steering proportional solenoid, a right steering proportional solenoid, a left braking proportional solenoid and a right braking proportional solenoid whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[018] Publication No. CN2427556 relates to a steering braking hydraulic operation device for a bulldozer. An oil return pipe of an operation control valve and an oil inlet pipe connected with a pilot control oil pump are connected with an oil tank. Four oil outlets of the operation control valve are connected with four oil inlet pipes of a steering brake pilot valve, and four oil outlet pipes are connected with four oil inlets of a steering brake control valve. An oil return pipe of the steering brake control valve and an oil inlet pipe connected with a steering brake oil pump are connected with an oil tank.
[019] Steering, hydraulic braking operation device for bulldozer whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[020] IN Publication No. 2701/DEL/2009 relates to a steering operation system comprising: one operating lever for inputting a steering instruction of a steering mechanism; a control valve actuated by the operating lever; and a plurality of hydraulic actuators selectively fluidly communicated with the control valve which are configured to actuate a plurality of steering valves that connected to the steering mechanism in a controllable manner and change the operating state of the steering mechanism in response to the steering instructions. This includes Steering operation system and method and work machine having such steering operation system whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[021] IN Publication No. 2131/MUMNP/2013 relates to control of a vehicle to perform a task employs first control input provided by a human operator and second control input provided by an automated controller. A relationship between the first control input and the second control input is determined. Either the first control input or the second control input is used to control the vehicle to perform the task based on the determined relationship. An indicator may be used to indicate to the operator when the control input provided by the human operator is being used to control the vehicle. In this collaborative vehicle control using both human operator and automated controller input whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[022] IN Publication No. 201841037391 relates to a system for steering a crawler. The system comprises a joystick, a controller, proportional valves (19LS, 19RS), and brake valves (20LB, 20RB). The crawler may turn in one of a left or a right direction based on the joystick movement that generates a voltage signal to generate an instruction signal in the controller for activating the proportional valves (19LS, 19RS) and the brake valves (20LB, 20RB), thereby turning the crawler in desired direction with ride comfort for a driver. This is control system for steering and braking of crawler equipment remote type whereas present invention provides mechanical linkage operated with hydraulic assisted steering and braking control system.
[023] Publication No. CN102649446 relates to a hydraulic steering wheel steering brake control device of a crawler walking machine. The device comprises an oil tank, a steering oil pump, a priority valve, a cycloid rotary valve type hydraulic steering gear, a steering brake valve, a steering wheel, a brake pedal and a brake cylinder group. According to the device disclosed by the invention, the cycloid rotary valve type hydraulic steering gear is operated by the hydraulic steering wheel to coordinate the steering brake valve and the brake cylinder group, only the steering wheel needs to be steered in steering, and only the brake pedal needs to be pedaled in service breaking or decelerating, so that the operation of a driver is very convenient. In addition, when the steering oil pump is failed, the manual steering of the steering wheel and the service braking can be realized, double insurances are realized, and the safety is greatly improved. This is hydraulic steering wheel steering brake control device of crawler walking machine whereas present invention is mechanical linkage operated with hydraulic assisted steering and braking control system.
[024] In high capacity bull dozer stopping and steering of this equipment while operations is difficult task for operators, because its braking and steering systems are operated by fully mechanical linkages, so operator has to put more effort for pressing the brake pedals, and mechanical steering levers.
[025] Since in high capacity bull dozer there is a mechanical linkage brake system to stop the equipment, operators required more effort to stop the equipment and while steering operations operator has to operate both steering levers as well as brake pedals also. So, for continuous dozer operations operator feel tired for short operating cycles which is directly impact on the production and operators health also.
[026] In order to overcome above listed prior art, the present invention aims to provide a hydraulic assisted steering and braking control system for easy operation of bull dozer, which results in operators comfort and effective operator working hours.
OBJECTS OF THE INVENTION:
[027] The principal object of the present invention is to provide a hydraulic assisted steering and braking control system for bull dozer.
[028] Another object of the present invention is to provide hydraulic assisted steering and braking control system for easy operation of bull dozer.
[029] Yet another object of the present invention is to provide hydraulic assisted steering and braking control system which results in operators comfort and effective operator working hours.
SUMMARY:
[030] The present invention relates to the hydraulic assisted steering and braking control system for easy operation of bull dozer, which results in operators comfort and effective operator working hours. The hydraulic assisted braking system added the additional hydraulic pressure to apply the brake when operator operates the brake pedal and results effortless braking. In steering operation additional pressure line circuit (tapped from existing steering pressure line) given for brake system, so that automatically brake will apply while operating the steering levers. This system avoids manual brake operations while steering. The invention, increases the operators comfort, intern increases the productivity.
BREIF DESCRIPTION OF THE INVENTION
[031] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[032] Figure 1 shows hydraulic assisted steering and braking control system.
[033] Figure 2a and 2b shows brake booster.
[034] Figure 3 shows working principle of hydraulic assisted steering system.
[035] Figure 4 shows flowchart according to the present invention.
[036] Figure 5 shows circuit diagram represents complete hydraulic system with hydraulic assisted steering and braking system.
DETAILED DESCRIPTION OF THE INVENTION:
[037] The present invention provides a hydraulic assisted steering and braking control system for easy operation of bull dozer, which results in operators comfort and effective operator working hours. The hydraulic assisted braking system added the additional hydraulic pressure to apply the brake when operator operates the brake pedal and results effortless braking. In steering operation additional pressure line circuit (tapped from existing steering pressure line) given for brake system, so that automatically brake will apply while operating the steering levers. This system avoids manual brake operations while steering. The invention, increases the operators’ comfort, intern increases the productivity.
[038] While operating the dozer, operator used to control the equipment by steering, gear shifting, braking, and positioning the attachments, in these operations braking and steering are prioritized since these are safety features. The steering system consists of two steering clutches and two brake drum (2) with the brake band (3) on either side of the sprocket. Each clutch assembly is consisting of brake drum (2), brake band (3) and springs (9). In normal conditions brake bands is in disengage conditions, Springs are loaded as to keep the brake band disengage and by depressing brake pedal will controls the brake band actions (fig 1). The brake band has its inner face fitted with a lining. This lining is secured to the band by riveting.
[039] The system comprises brake pedal (1), brake drum (2), brake band (3), brake lining (4), rod (5), lever (6), bracket (7), booster cover (8), spring (9) and booster cylinder (10). In the hydraulic assisted braking system when operator slightly depresses the brake pedal this small force is sufficient to open the pressure port in the booster cylinders (10) and additional hydraulic pressure will act on the booster piston which is pushes the lever (6) downwards through linkage so that, it encloses the brake band and brake liners (4) will holds the brake band firmly and brake will apply. In this system very less effort is sufficient to operate the brake pedal and to stop the running equipment completely.
[040] Figure 2a and 2b shows brake booster comprising operator pedal (1a), brake booster cylinder (2a), booster valve / plunger (3a), booster piston (4a) and brake lever (5a). Here a separate line tapped from the existing steering circuit and connected to the brake booster (2a). Operator brake pedal is connected to brake lever through mechanical linkages and brake lever connected to plunger (3a) which is connected to booster piston (4a). When operator slightly depresses the brake pedal (1a), it operates the brake lever (5a) intern plunger(3a) will move slightly shifts to next position then pressurized oil flow will connect to the piston which adds the additional pressure to move the booster piston (4a) which compress the brake band through levers. In this system a force is required to just shift the booster valve(3a), and remaining force will come from pressurized oil to operate the brake band.
[041] Figure 3 shows working principle of hydraulic assisted steering system. When the steering lever on the turning side is pulled, the steering clutch on turning side is disengaged. However, the power remains partially on the clutch and drives the track shoe on the turning side, resulting in a wide turning radius.
[042] In order to improve on this, it is so designed as to apply a brake on the outer drum while steering, by supplying additional hydraulic pressure on brake booster piston from the steering control valve.
[043] As shown in fig.1 in the Hydraulic assisted braking system when operator slightly depresses the brake pedal this small force is sufficient to open the pressure port in the booster cylinders and additional hydraulic pressure will act on the booster piston which is pushes the lever (6) downwards so that it encloses the brake band and brake will apply.
[044] When the steering lever is pulled, the steering control valve spool will move to next position so that the pressurized oil will get connected to the clutch disengagement line and clutch will disengage (P to B). The same oil will connect to the Brake booster piston line also as shown in above circuit Fig.3. As pressurized oil pushes the piston, through linkages brake band will compresses and along with the disengagement of clutch brake also will apply to steer effectively.
[045] This system, called an interlock steering clutch and brake, replaces the conventional system which exclusively relied on the control linkage.
[046] Figure 4 shows flowchart including following steps:
[047] Step 1. When operator want control or stop the equipment, he will depress the both brake pedals to stop the equipment, this braking force will transfer through the linkages to the brake booster lever.
[048] Step 2. The brake booster lever will push the plunger intern connected to piston, through this plunger pressurized oil from steering pump/circuit will enters in to the booster cylinder.
[049] Step 3. Pressurized oil will pushe the piston which is connected to the brake band through linkages.
[050] Step 4. Brake band compresses against brake drum.
[051] Step 5. Brake applies and equipment will stop.
[052] Step 6. Whenever operator wants to steer the equipment, he will pull the respective lever to steer the equipment at particular direction (LH/RH).
[053] Step 7. The steering control valve spool will move to next position so that pressurized oil will connect to clutch disengagement port, as well as brake booster also.
[054] Step 8. Clutch will disengage and power will cut off to the particular drive.
[055] Step 9. Parallelly brake also will apply and quick steering will take place.
[056] The circuit diagram shown in Fig.5 represents complete hydraulic system with Hydraulic assisted steering and braking system. In a steering circuit, steering pump (2) will take the oil from steering case (1) and supply the oil to steering clutches (7) and (8) through steering control valve (4) and steering filter (3), here a separate line tapped from the existing steering circuit and connected to the RH and LH brake boosters (5) and (6). When operator slightly depresses the brake pedal (9) opens the pressure port in the booster cylinders and additional hydraulic pressure will act on the booster piston which is pushes the lever downwards through linkage so that, it encloses the brake band and brake will apply.
[057] When operator pull the steering lever (10) for particular spool will shift to next position i.e., steering pump pressure oil will connect from ‘P’ port to ‘B’ port and this oil will disengages the clutch (7/8), so drive will cut off to the particular side. The same oil parallelly will connect to the Brake booster piston (5/6) line also as shown in above circuit, as pressurized oil pushes the piston, through linkages brake band will compresses and brake will apply, so along with the disengagement of clutch, brake also will apply to steer effectively.
[058] This system, called an interlock steering clutch and brake, replaces the conventional system which exclusively relied on the control linkage.
[059] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.
,CLAIMS:
WE CLAIM:
1. A hydraulic assisted steering and braking control system comprises-
a) two steering clutches and two brake drum (2) with the brake band (3) on either side of the sprocket characterized in that each clutch assembly is consist of brake drum(2), brake band(3) and springs (9) wherein in normal conditions brake bands is in disengage conditions, springs are loaded as to keep the brake band disengage and by depressing brake pedal controls the brake band actions and wherein a force is required to just shift the booster valve(3), and remaining force comes from pressurized oil to operate the brake band.
b) brake lining (4), rod (5), lever (6), bracket (7), booster cover (8), spring (9) and booster cylinder (10) and when operator slightly depresses the brake pedal this small force is sufficient to open the pressure port in the booster cylinders (10) and additional hydraulic pressure will act on the booster piston which is pushes the lever (6) downwards through linkage so that, it encloses the brake band and brake liners (4) will holds the brake band firmly and brake is applied.
c) the brake booster comprises operator pedal (1) connected to brake lever through mechanical linkages and brake lever connected to plunger (3) which is connected to booster piston (4), brake booster cylinder (2), booster valve / plunger (3), booster piston (4) and brake lever (5) wherein a separate line tapped from the existing steering circuit and connected to the brake booster (2).
2. The hydraulic assisted steering and braking control system, as claimed in claim 2, wherein when operator slightly depresses the brake pedal (1), it operates the brake lever (5) intern plunger (3) moves slightly shifts to next position then pressurized oil flow connects to the piston which adds the additional pressure to move the booster piston (4) which compress the brake band through levers.
3. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein when the steering lever on the turning side is pulled, the steering clutch on turning side is disengaged but power remains partially on the clutch and drives the track shoe on the turning side, resulting in a wide turning radius.
4. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein a brake is applied on the outer drum while steering, by supplying additional hydraulic pressure on brake booster piston from the steering control valve.
5. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein when operator slightly depresses the brake pedal this small force is sufficient to open the pressure port in the booster cylinders and additional hydraulic pressure will act on the booster piston which is pushes the lever (6) downwards so that it encloses the brake band and brake will apply.
6. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein when the steering lever is pulled, the steering control valve spool will move to next position so that the pressurized oil will get connected to the clutch disengagement line and clutch will disengage (P to B) and the same oil will connect to the brake booster piston line and as pressurized oil pushes the piston, through linkages brake band will compresses and along with the disengagement of clutch brake also will apply to steer effectively.
7. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein method including following steps:
a) When operator want control or stop the equipment, he will depress the both brake pedals to stop the equipment, this braking force will transfer through the linkages to the brake booster lever.
b) The brake booster lever will push the plunger intern connected to piston, through this plunger pressurized oil from steering pump/circuit will enters in to the booster cylinder.
c) Pressurized oil will push the piston which is connected to the brake band through linkages.
d) Brake band compresses against brake drum.
e) Brake applies and equipment will stop.
f) Whenever operator wants to steer the equipment, he will pull the respective lever to steer the equipment at particular direction (LH/RH).
g) The steering control valve spool will move to next position so that pressurized oil will connect to clutch disengagement port, as well as brake booster also.
h) Clutch will disengage and power will cut off to the particular drive.
i) Parallelly brake also will apply and quick steering will take place.
8. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein in a steering circuit, steering pump (2) will take the oil from steering case (1) and supply the oil to steering clutches (7) and (8) through steering control valve (4) and steering filter (3), here a separate line tapped from the existing steering circuit and connected to the RH and LH brake boosters (5) and (6) and when operator slightly depresses the brake pedal (9) opens the pressure port in the booster cylinders and additional hydraulic pressure will act on the booster piston which is pushes the lever downwards through linkage so that, it encloses the brake band and brake will apply.
9. The hydraulic assisted steering and braking control system, as claimed in claim 1, wherein when operator pull the steering lever (10) for particular spool shifts to next position i.e. steering pump pressure oil connects from ‘P’ port to ‘B’ port and this oil disengages the clutch (7/8), so drive will cut off to the particular side, the same oil parallelly connects to the Brake booster piston (5/6) line, as pressurized oil pushes the piston, through linkages brake band will compresses and brake is applied, so along with the disengagement of clutch, brake is also applied to steer effectively.