Claims:We claim:

1. A dual mode braking system for agricultural tractors comprising of

a brake housing (1);
a actuating unit assembly (2);
a static clutch sleeve (3);
a bull gear shaft (4);
a inner guide (5);
a dynamic clutch sleeve (6);
a circlip (7);
a bearing (8);
a needle roller bearing (9);
a cable assembly (10);
a return spring (11);
a cover (12);
a inner friction disc (13);
a outer friction disc (14); and
a thrust bearing (15)

characterized in that the brake housing (1), the actuating unit assembly (2), and the static clutch sleeve (3) are mounted externally on the bull gear shaft (4), the dynamic clutch sleeve assembly (6), the static clutch sleeve (3) and the return spring (11) all being housed inside the cover (12) and mounted to the brake housing (1) with the help of fasteners.

2. A dual mode braking system for agricultural tractors as claimed in Claim 1 wherein the inner guide (5) along with the needle roller bearing (9), is assembled on to the dynamic clutch sleeve (6) with the help of the circlip (7) which constitutes the dynamic clutch sleeve assembly, and this slides over the bull gear shaft (4).

3. A dual mode braking system for agricultural tractors as claimed in Claim 1 wherein a thrust bearing member (15), is sandwiched between the Inner guide (5) and the dynamic clutch sleeve (6).

4. A dual mode braking system for agricultural tractors as claimed in Claim 1 wherein a bearing (8) is assembled inside the inner guide (5) as a guide for the cable assembly (10).

5. A dual mode braking system for agricultural tractors as claimed in Claim 1 wherein the dynamic clutch sleeve assembly (6) is always in engagement with the static clutch sleeve (3) with the help of the return spring (11)

6. A dual mode braking system for agricultural tractors as claimed in Claim 1 wherein the inner friction disc (13) slides over the bull gear shaft (4) and the outer friction disc (14) slides over the dynamic clutch sleeve (6).

7. An dual mode braking system for agricultural tractors as claimed in Claim 1 and its working thereof wherein when the hand selector lever is actuated, the cable (10) pulls the dynamic clutch sleeve assembly, as a result the dynamic clutch sleeve (6) gets pulled out, it gets disconnected from the static clutch sleeve (3), completely isolating itself from the outer friction discs (14)as it slides out from the dynamic clutch sleeve(6) from rotating along with the bull gear shaft (4).

8. An dual mode braking system for agricultural tractors as claimed in Claim 1 and its working thereof wherein the inner guide (5), slides on the bull gear shaft (4) till the dynamic clutch sleeve (6) gets disengaged from the static clutch sleeve (3).

9. An dual mode braking system for agricultural tractors as claimed in Claim 1 and its working thereof wherein the needle roller bearing (9) is used for free rotation of the inner guide (5) inside the spline sleeve, the disengaging of the spline sleeve stopping friction discs (13) (14) from rotating with the bull gear shaft (4).

10. An dual mode braking system for agricultural tractors as claimed in Claim 1 and its working thereof wherein when the hand selector lever is actuated, the dynamic clutch sleeve assembly (6) gets connected with the static clutch assembly (3) due to the return spring (11) as the return spring (11) pushes the clutch sleeve assembly towards the clutch static thereby engaging the friction discs (13), (14) to start rotating along with bull gear shaft (4).

Dated this 12th day of June 2019
N. Surya Senthil – IN/PA-736
For JUS MAXIMA LAW OFFICES
To: (Agent for Applicant)
The Controller of Patents
Patent Office in Chennai

, Description:TITLE
DUAL MODE BRAKING SYSTEM FOR AGRICULTURAL TRACTORS

FIELD OF THE INVENTION

This invention relates to mechanical engineering, specifically automobile engineering and relates to agricultural tractors –Multiplate disc(s) (MPD) oil immersed brake system and Dry brake system. This invention more specifically relates to dual mode braking system for agricultural tractorsand relates to optimized use of friction disc based on application using selector mechanism for tractor applications containing hand lever or brake pedal and mechanical linkages.
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BACKGROUND OF THE INVENTION

Agricultural tractors generally used in India ranges between 25~57 HP. MaximumSpeed of the vehicle varies between 25~35 KPH. Mainly used for ploughing, tilling, disking, harrowing, planting, and similar tasks. These tractors are currently equippedwith brakes in Rear Axle (Dry and Wet MPD brakes with mechanical actuation)with independent left and right wheel-braking. This independent left and right wheel-braking augments the steering of the tractor when it is necessary to make a sharp turnby applying differential brakes on the two rear wheels. The split brake pedal is also used in mud or soft soil to control tire spinning due to loss of traction.

It was observed that all the applications do not require equal Braking torque. It is known that at the time of Puddling & Haulage the system requires different braking torque. This difference in brake torque requirements lead to develop a brake system to achieve higher friction life and better fuel economy as per driver choice.

The use of disc brakes on motor vehicle wheels has been known for many years.These disc brakes operate in the following manner: firstly, a metal disc is secured in rotation with the rim of the wheel, said disc (Brake Rotor) being in a plane perpendicular to an axial direction corresponding to the axis of rotation of the wheel.

On the other hand, on a fraction of its circumference and at its periphery, the disc (Brake Rotor) is inserted between two facing pads integral with a fixed yoke or able to slide by a so-called axial stroke in said axial direction, and to exert a pressure on the rotating disc (Brake Rotor) by means of a master cylinder, a pressure on the brake pedal actuating said master cylinder by means of a hydraulic fluid.

In addition to size, cost and weight, there are the criteria of efficiency, proficiency and longevity. Brake wear is a longevity problem and a longer brake pad life and brake disc (Brake Rotor) life are desired by vehicle manufacturers which are increasingly providing long term service warranties for their vehicles, as well as for the vehicle owner who ultimately pays for brake replacement in one manner or the other. Even though the vehicle operator is not operating the braking pedal and is steering the vehicle along a straight line path, the brake pads are rubbing against the fixed brake and causing the temperature thereof to rise substantially above ambient. The cornering of a vehicle and sharp turning may also shift the slidable brake caliper into rubbing contact with the fixed brake disc. In a current production vehicle of lightweight and having a fixed brakesystem, the disc (Brake Rotor) temperature was measured at least 35° C. above ambient when the ambient temperature is between 20° to 30° C. This is a good indication that current fixed brake systems in automotive vehicles have considerable residual torque at the off-brake condition, and concomitant wear and fuel energy waste.

Unlike the disc Brakes found on automotive vehicles, the agricultural tractor brake system has multiple intermediate plates and multiple friction disc(s), where friction disc(s) are rotating, and the intermediate plates are stationary. Actuating disc exerts pressure on the rotating friction disc(s) which inturn moves the disc(s) axially and pushes it against the static intermediate plates, during braking. Hence the parameters viz., Residual torque, associated wear and fuel consumption are found to be severe in the agricultural tractors braking system when compared to automotive braking system.

There is a need of a mechanism to engage and disengage the number of friction discs to provide torque according to application needs, thereby reducing the residual drag, which will result in increased lining life and reduced fuel consumption.

Some of the prior art in this field reveal various improvements made over the years in the art, specifically in tractor brakes.

Indian Patent Application No: 2669/MUM/2014 discloses ahydraulic trailer brake system operated by the tractor's own hydraulic system and that, too, without a separate trailer brake control valve. The trailer brake system includes a hydraulic control valve equipped with an isolating valve for prioritizing of fluid flow either to trailer brake outlet or for implement operation. The hydraulic tractor brake system comprises: a hydraulic pump; a brake pedal; a draft lever; the tractor hydraulic system includes a hydraulic control valve, a combination of isolating valve and shut-off valve and a draft plunger; a plurality of linkages are provided for connecting and actuating the brake pedal, the draft plunger, the draft lever and the hydraulic control valve. A gap configured between the draft lever-hydraulic control valve linkage and the hydraulic control valve is adjusted by using draft lever for facilitating the synchronization of the tractor and trailer brake systems.

Indian Patent Application No: 201641037309 claims an all wheel braking system for a two wheel drive tractor to provide higher braking efficiency, comprises of plurality of brake assemblies (105, 106, 108,109), said plurality of brake assemblies (105, 106, 108, 109) actuates simultaneously and thus brake is applied on the dead axle (104) and the live axle (107). This system improves the braking functionality of the braking system by approximately 25~40%.

Indian Patent Application No: 5772/DELNP/2010 discloses a tractor steer-by-braking (SBF) pedal arrangement (10). The pedal arrangement (10) is characterized by having a central brake pedal (11) connected on one side to a right side pedal (12), and on the other side to a left side pedal (13). The central brake pedal (11) acts on a brake system (SBF) to produce the desired braking action. Each of the two side pedals (12, 13), when foot-operated by the driver, generate an activating signal to activate an electronic brake system, which only activates the brake required to steer-by-braking (SBF) in the desired (right or left) direction.

Indian Patent Application No: 1412/KOL/2006 claims an installation of braking device arrangement in the trailer Truck with a synchronization of Tractor brake. The new braking device comprising of installation of new compression with accessories in the tractor and a pneumatic brake attachment with a master cylinder with a provision of a brake fluid container and an additional air tank is provided with the tractor to cater air to air tank of the trailer truck via a flexible air pipe. The trailer equipped with a pneumatic braking device which is controlled by a hand lever by the driver via a control brake - valve of the tractor.

With the foregoing in mind, the need of the hour is to develop a dual mode braking system for agricultural tractors which can engage and disengage the number of friction discs to provide torque according to application needs, thereby reducing the residual drag, which will result in increased lining life and reduced fuel consumption.
This invention eventually proves to be performance efficient, cost effective and eases the assembly.These and other objects of the invention will become more apparent in the course of the ensuing specification and claims when taken with the accompanying drawings.

Further it will be apparent to those skilled in the art that the objects of this invention have been achieved by providing a dual mode braking system for agricultural tractors using application based selector mechanism which is unique in nature unlike existing tractor brake systems as described in the above prior art. Various changes may be made in and without departing from the concept of the invention. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing and modifying other methods and structures for carrying out the same purpose of the present invention. Further, features of some stages disclosed in this application may be employed with features of other stages. Therefore, the scope of the invention is to be determined by the terminology of the following claims and the legal equivalents thereof.

OBJECTIVES OF THE INVENTION

This invention may be summarized, at least in part, with reference to its objects.

The foremost object of the present invention is to present a dual mode braking system for agricultural tractors which can achieve higher friction life with selective use of friction plates.

Another object of the present invention is to present a dual mode braking system for agricultural tractors that has lower brake drag during brake-off condition (i.e. achieved through two disc operation).

Another object of the present invention is to present a dual mode braking system for agricultural tractors wherein due to lesser drag there is a better fuel economy.

Another object of the present invention is to present a dual mode braking system for agricultural tractors with selector mechanism where the brake torque selection is left to the discretion of the user to select application based on the need.

Another object of the present invention is to present a dual mode braking system for agricultural tractors with huge cost benefits.

Another object of the present invention is to present a dual mode braking system for agricultural tractors with mechanical brake actuation using multi plate disc brake.

Another object of the present invention is to present a dual mode braking system for agricultural tractors which provides better brake lining life.

Another object of the present invention is to present a dual mode braking system for agricultural tractors which provide slow residual drag

A further object of the present invention is to present a dual mode braking system for agricultural tractors which has optimized use of friction disc using application based selector mechanism.

Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.

SUMMARY OF THE INVENTION

The present invention embodies a dual mode braking system for agricultural tractors to provide torque according to application needs.
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The dual mode braking system is mechanically actuated in a disc wet brake system of Tractor which is link operated. A cable mechanism with hand selector lever or integrated with Brake pedal is used to perform the function.

The entire dual mode braking system assembly comprises of the following parts:

1. Brake Housing
2. Actuating Unit Assembly
3. Static Clutch Sleeve
4. Bull Gear Shaft
5. Inner Guide
6. Dynamic Clutch Sleeve
7. Circlip
8. Bearing
9. Needle Roller Bearing
10. Cable Assembly
11. Return Spring
12. Cover
13. Inner Friction Disc
14. Outer Friction Disc
15. Thrust Bearing

DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will be more readily apparent by persons skilled in the art when considered in reference to the following description and when taken in conjunction with the accompanying drawings listed below

Figure 1 is a cross sectional view of the present invention assembly.

DETAILED DESCRIPTION

The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of particular applications of the invention and their requirements. The present invention can be configured as follows:

The present invention is dual mode braking system for agricultural tractorswhich has optimized use of friction disc based on application using selector mechanism.

Construction

According to a preferred embodiment of the present invention, as shown in Figures 1, the present invention assembly components are as follows:

1. Brake Housing
2. Actuating Unit Assembly
3. Static Clutch Sleeve
4. Bull Gear Shaft
5. Inner Guide
6. Dynamic Clutch Sleeve
7. Circlip
8. Bearing
9. Needle Roller Bearing
10. Cable Assembly
11. Return Spring
12. Cover
13. Inner Friction Disc
14. Outer Friction Disc
15. Thrust Bearing

According to a preferred embodiment of the present invention, as shown in Figure 1, the complete brake assembly is mounted externally on the bull gear shaft (4). The brake assembly consists of the brake housing (1), the actuating unit assembly (2), andthe static clutch sleeve (3) mounted on to the bull gear shaft (4).

According to a preferred embodiment of the present invention, as shown in Figure 1, the inner guide (5) along with the needle roller bearing (9), is assembled on to the dynamic clutch sleeve (6) with the help of the circlip (7)which constitutes the dynamic clutch sleeve assembly, this slides over the bull gear shaft (4).

According to a preferred embodiment of the present invention, as shown in Figure 1, in order to reduce friction between the rolling parts, a thrust bearing member (15), is sandwiched between the Inner guide (5) and Dynamic Clutch Sleeve (6). A small bearing (8) is assembled inside the inner guide (5) which acts as a guide for the cable assembly (10).

According to a preferred embodiment of the present invention, as shown in Figure 1, the Dynamic clutch sleeve assemblyis always in engagement with the Static clutch sleeve (3) with the help of the Return spring (11), these together is housed inside a Cover (12) which is mounted to the brake housing (1) with the help of fasteners.The inner friction disc (13) slides over the bull gear shaft (4) and the outer friction disc (14) slides over the Dynamic clutch sleeve (6).

Working:
According to a preferred embodiment of the present invention, a cable mechanism with hand selector lever or integrated with Brake pedal is used to perform the function.

A. Low Torque Mode(Friction disc - Disengaged mode):

According to a preferred embodiment of the present invention, when the hand selector Lever is actuated, the cable (10) pulls the Dynamic Clutch Sleeve assembly, as a result the Dynamic Clutch Sleeve (6) gets pulled out, it gets disconnected from the Static Clutch Sleeve (3), completely isolating itself from the outer friction discs (14)as it slides out from the Dynamic Clutch Sleeve(6) from rotating along with the bull gear shaft (4).

According to a preferred embodiment of the present invention, the Inner Guide (5), slides on the Bullgear shaft(4) till the Dynamic Clutch Sleeve (6)gets disengaged from the Static Clutch Sleeve (3).

According to a preferred embodiment of the present invention, the Needle roller Bearing (9) is used for free rotation of the Inner guide(5) inside the Spline Sleeve.

According to a preferred embodiment of the present invention, the disengaging of the spline Sleeve stops friction discs(13) (14) from rotating with the Bullgear shaft (4).
High Torque Mode(Friction disc - Engaged mode):
According to a preferred embodiment of the present invention, when the hand selector Lever is actuated, the Dynamic Clutch Sleeve assembly (6) gets connected with the Static Clutch assembly (3) due to the Return spring (11)as the return spring(11) pushes the Clutch Sleeve assembly towards the Clutch Static thereby engaging the friction discs (13), (14) to start rotating along with Bull gear shaft (4). All the friction discs(13), (14) start rotating alongwith the Bull gear shaft (4).

While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.

It will be apparent to those skilled in the art that the objects of this invention have been achieved by providing the above invention. However various changes may be made in the structure of the invention without departing from the concept of the invention. Therefore, the scope of the invention is to be determined by the terminology of the following claims and the legal equivalents thereof.

Dated this 12thday of June 2019
N. Surya Senthil – IN/PA-736
For JUS MAXIMA LAW OFFICES
To: (Agent for Applicant)
The Controller of Patents
Patent Office in Chennai