Claims:CLAIMS

What is claimed is:

1. Crash safe booster comprising of
a Collapsible tie rod (1);
a pair of Sleeves (2);
a Front shell (3);
a Valve body (4);
a Return spring (5);
a Holder (6);
an Adjusting screw (7);
an Output rod (8);
a Grommet (9);
an Output rod retainer (10);
a Diaphragm plate (11);
a Diaphragm (12);
a Rear shell (13);
a Ratio disc(14);
a Poppet (15);
a Dust cover (16);
a Filter (17);
an Input rod (18);
a Circlip (19);
a Threshold spring (20);
a Poppet retainer (21);
a Poppet retainer spring (22);
a Plunger valve (23);
a Dilag seal (24);
a Reaction disc, (25);
a Non Return Valve (26); and
Studs (27)
characterized in that the Sleeves (2) are rigidly crimped to the booster front shell (3).

2. The crash safe booster as claimed in Claim 1 wherein the collapsible tie rods (1) take an interference fit with the sleeve (2).

3. The crash safe booster as claimed in Claim 1 wherein under extreme loading, the sleeves (2) along with the booster front shell (3) will slide over the tie rods (1).

4. The crash safe booster as claimed in Claim 1 wherein the collapsible tie rods (1) on the other side passes through the diaphragm plate (11), the diaphragm (12) & the booster rear shell (13).

5. The crash safe booster as claimed in Claim 1 and working thereof wherein during a normal brake application, the reactive forces from the master cylinder is split into half and transferred through the flanges to the two sleeves (2) equally, the sleeve (2) in-turn transferring the load to the tie rod (1), through the interference between them, the load being carried through the tie rods (1) and transferred to the firewall.

6. The crash safe booster as claimed in Claim 1 and working thereof wherein
during a frontal vehicle crash, the impact load generated is transferred to the master cylinder body, which is then transferred to the sleeves (2) through the master cylinder flange.

7. The crash safe booster as claimed in Claim 1 and working thereof wherein
during a frontal vehicle crash, the crash load generated is sufficient enough to break the interference between tie rod (1) & sleeve (2), making the sleeve (2) slide over the tie-rod (1).

8. The crash safe booster as claimed in Claim 1 and working thereof wherein
during a frontal vehicle crash, the entire load is transferred to the booster front shell (3) before being transferred to the tie rod (1).

9. The crash safe booster as claimed in Claim 1 and working thereof wherein
during a frontal vehicle crash, as the sleeve (2) slides, the booster front shell (3) absorbs the impact load & crumbles, thus preventing the load from reaching the vehicle firewall.

10. The crash safe booster as claimed in Claim 1 and working thereof wherein
during a frontal vehicle crash, the brake pedal bracket is prevented from being deflected avoiding possible injuries to the driver, isolating the pedal gear & other associated parts from the impact load.

Dated this 1st day of March 2019
N. Surya Senthil – IN/PA-736
For JUS MAXIMA LAW OFFICES
(Agent for Applicant)
To
The Controller of Patents
Patent Office in Chennai

, Description:TITLE
Crash Safe Booster

FIELD OF THE INVENTION

This invention generally relates to mechanical engineering, specifically automobile engineering and particularly relates to a Vacuum Booster. More particularly this invention relates to a simple, novel, Crash Safe booster that enhances the driver safety during a frontal crash with few more added benefits.

BACKGROUND OF THE INVENTION

A vacuum brake booster is a system that utilises the vacuum energy supplied by the engine free of charge and converts these to auxiliary forces, which assist the pedal actuation by the driver. The entire brake unit can also be viewed and represented as a combination of foot force multiplier and brake pressure generator with integrated brake fluid reservoir (tank).

The vacuum brake booster is based on the principle of a two-chamber system. By utilizing pressure differentials caused by evacuation and requirement oriented controlled build-up of atmospheric pressure, servo / auxiliary forces are applied to an inner working piston, which, depending on the design of the unit, can reach many times the input force (translated pedal force).This has the effect that the system pressure required for braking can be built up with lowest input of force. The brake booster is a contribution to relieving the driver and to reducing the stopping distance. With the present traffic situation brake boosting must be considered indispensable with respect to safety and comfort.

With the engine running or vacuum applied the pressure level is identical in both chambers of the brake unit, as long as the brake is not operated (“released position”). In this situation vacuum and atmosphere compartments are still connected by open channels. An internal valve (poppet and plunger) blocks the access to atmosphere (surrounding air). Starting actuation ("partial load position") results in an immediate separation of both pressure compartments and an almost simultaneous aeration (filling) of the rear atmosphere chamber. The front vacuum chamber always remains connected with the vacuum source, thereby maintaining the required vacuum. The required air flow into the atmosphere compartment (generation of the chamber differential pressure) is quantitatively controlled by a regulating link (poppet and plunger) – according to driver requirements and driving situation. The pressure gradient affecting the working piston (diaphragm plate with diaphragm) generates the servo / auxiliary force. According to the internal booster ratio, servo and input forces (input force or foot force translated by the pedal) are in direct relation to each other, over the entire control range, until the full atmospheric pressure in the rear compartment is reached.
When stopping the foot force (pedal stop), the air inlet will be immediately closed, causing an equilibrium of forces between input and servo force on the one side and the booster output force on the other side. Once the so-called knee-point pressure (max. servo force applied / full air pressure in atmosphere chamber) is reached, a further pressure increase in the hydraulic braking system of the vehicle is only possible via the foot force of the driver (translated pedal force). For this full load area this also applies in reverse order when relieving the brake pressure down to the knee-point (i.e. pressure reduction equivalent to the reduction of force).

During the return stroke inside the control range, the reduction of input force switches the control link (poppet and plunger) to opposite direction. This means that the air inlet is now closed first, before the connecting channel between atmosphere and vacuum chamber is opened. At this moment the evacuation of air from the atmosphere chamber through the vacuum chamber to the vacuum source (intake manifold or vacuum pump) is started. The resulting reduced pressure gradient relieves the working piston and thereby reduces the servo force. When releasing the pedal completely this evacuation process continues until the pressures are equal in both compartments. However, if the pedal force is only partially relieved, air will only be evacuated until a new equilibrium of forces has been established at the respective resetting position (input and servo load to output load).
In this so-called "partial load position or partial braking" the poppet has a double sealing function. In this situation the pressure differentials between vacuum chamber and atmosphere chamber as well as the atmosphere chamber to the environment (external air) must be sealed. After releasing the pedal the resetting mechanisms (compression springs) of master cylinder and booster ensure complete relieving of the hydraulic brake pressure (pressure compensation to reservoir) and reliable resetting of the vacuum piston to end position. In contrast to this, the entire central control train of the brake booster (control / input unit) with the attached brake pedal is returned and reliably held against the stop only by the internal valve springs and the pedal return spring.

It is important to know, that a vacuum non-return valve, installed in the feed line from engine to brake booster, maintains a vacuum reserve for approx. 3 to 6 brake pedal operations, even if the engine is shut down (serves also as a lock against the diffusion of gasoline vapours into the brake booster). In this case both the vacuum level and the servo force obviously drop after each actuation. The respective drop or the number of still assisted subsequent braking operations depends on the intensity of the applied load, because the "vacuum consumption" depends on this load. Once the vacuum is completely exhausted braking is only possible without booster assistance, because the internal pressure in the brake booster in both compartments is identical with the atmospheric pressure.
The driver must be aware of this in respective situations and adapt his way of driving accordingly.

The outer casing of the brake booster, which consists of two half shells, is the shielding against the atmosphere and provides the cylinder space for the generation of the vacuum. With a conventional booster unit (non - light shell compact), all applied forces must be absorbed by the assembled housing parts - rear shell and front shell. This applies for both the generation of vacuum (pressure load) and the actuation, especially if this actuation is performed without vacuum assistance. In this case the strength of the external joining of both half shells is of particular importance. In contrast, a light shell compact booster has two tie bolts inserted through the brake booster that takes up the major share of all tensile and supporting forces under the application of vacuum and also during operation / braking. With this the use of material for the housing can be halved, providing the basis for the decisive weight advantage. The so-called working piston or vacuum piston moving inside the housing generates the booster force (servo / auxiliary force) and transmits it to the master brake cylinder mounted on the front. The rolling diaphragm, tightly clamped between both housing sections, is normally in large area contact with the working piston (diaphragm plate) and seals both pressure compartments (vacuum and atmosphere chamber) to each other. A valve housing, centrally arranged in the working piston, provides the connection between inside of housing and atmosphere (outside air), required for ventilation. A ring-shaped sealing element mounted in the rear shell with vulcanized steel inlay - dilag bushing ensures strong and reliable sealing towards the cylindrical area of the valve housing, in static as well as dynamic state. The heart of the booster is the centrally arranged control unit, consisting of the main elements poppet, plunger and input rod. This control assembly moves relative to the valve body and enables atmospheric air to flow in and out of the booster as required when operating and releasing the brake pedal (input rod). The stream in air is thereby guided through a filter / damping element, which has been optimized under noise and fluidic aspects.

An important part, centrally arranged in the booster, is the reaction disc. All forces related with the braking process run through this rubber disc. Besides this it has an additional sealing function and in connection with the ratio disc, it contributes significantly to the shape of the main performance characteristics. The tie bolts, which are normally fastened in the front section of the shell (front shell) are the backbone of the light shell compact design. Due to their variety of duties, these parts can also be considered multi-function parts. These functions include;

- Fastening of the complete unit to the bulkhead of the vehicle.
- Fastening of the master brake cylinder.
- Sealing function in front shell.
- Absorption of support forces during application of vacuum.
- Piston rod function for diaphragm / minor diaphragm (dynamic sealing).
- Sealing towards adjuster nut by means of coated thread.
- Reduced deflection under pedal load (loss pedal stroke).
- Absorption of all relevant tensile forces during the braking process.

A Tandem brake booster which is also based on the same principle, has two cylinder compartments and working pistons arranged behind one another producing almost double the servo force. All tandem boosters are light shell compact booster which will have tie rods as seen earlier. Hence a light shell compact booster with tie rod design is mostly used in automotive braking applications because of its above mentioned advantages. But the problem with the current light shell compact booster design is, during a crash when the under bonnet parts in contact with the master cylinder, it will transfer the entire impact load to the firewall through the tie rod setup in it. As a result, the firewall will deform creating a deflection in the pedal mounting bracket. This lifts the pedal assembly up transferring the entire force to driver’s foot creating severe injuries to the driver’s leg. Since, there are more chances for the driver to have his leg over the brake pedal (as he would have tried applying brakes at that time to prevent the crash), this could be a severe threat to the driver’s safety during a frontal crash.

Some of the prior art in this field reveal various improvements made over the years in the art, specifically in crash safe assemblies for vehicles.

United States Patent 7712570 claims a brake assembly configured to bias the master cylinder to rotate upward in a crash which induces the brake pedal to rotate down and away from the driver. This is achieved with a reduced number of parts, an angle reservoir for the initial position, a localized crush zone in the booster all configured to use the assembly's contact with the lower dash panel as a fulcrum point inducing downward rotation of the brake pedal. The present invention takes geometric advantage of its position proximate the lower dash panel to sure that when the engine compartment portion is pushed rearward toward the occupant compartment, the localized crush zone of the booster case induces upward rotation of the master cylinder causing the booster to pivot about the lower dash panel and cause the parallel brackets to rotate downward.

WIPO Patent Application WO/2001/074628 discloses pedals for use in motor vehicles. The aim of the invention is to prevent the pedal lever (4) from hitting the leg (13) of the driver, when a crash occurs, through displacement of the actuating rod (11) of the brake booster (9). This is achieved by preventing the pedal lever (4) from rotating in a direction counter to the direction of actuation. Several measures are provided. One of said measures consists in exclusively allowing forces to be transmitted in one direction of actuation. This can occur with the aid of a traction rod (14) which is unable to transmit any pressure forces. Another measure consists in mounting the pedal lever on a separately arranged cross member (21), as opposed to mounting it against the engine compartment.

With the foregoing in mind, therefore it is the need of the hour to develop a light shell compact booster which should be capable of absorbing the impact load transfer from a crash without passing it to the firewall. This has to be done without any major modifications in the present design considering the cost associated factors.

The present invention attains this objective and addresses the major problem of load transfer to the firewall in case of a crash by replacing the existing tie rods with a collapsible tie rod setup. In normal operating conditions, the collapsible tie rod system will transfer reactive loads coming from master cylinder to the firewall as in the case of a normal light shell compact booster & in case of a crash, the entire crash load will be transferred to the booster front shell instead of being transferred to the firewall.

The present invention involves a booster containing sleeves which are crimped to the booster front shell unlike a conventional light shell compact booster where the tie rods are directly crimped to the booster front shell. The tie rods are inserted through the sleeves with a minimal interference. The master cylinder is mounted over the tie rods as in a regular light shell compact booster.

Further it will be apparent to those skilled in the art that the objects of this invention have been achieved by providing a novel Crash Safe Booster (CSB) which is unique in nature unlike existing light shell compact booster 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 Crash Safe Booster capable of absorbing the shock loads developed during a crash enhancing the safety of driver during a frontal crash.
Another object of the present invention is to provide a crash safe booster which makes tight packaging possible, thereby giving a chance to increase the cabin space.
Another object of the present invention is to provide a crash safe booster that reduces the damage incurred to the pedal gear & related parts during a crash thereby reducing the replacement / repair cost.
Yet another object of the present invention is to provide a Crash Safe Booster that has less weight than the conventional light shell compact booster.
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 crash safe booster that can be used in hydraulic braking systems of cars, SUVs, MUVs & commercial vehicles. The present invention consists of a crash safe booster which is simple in construction.

The entire crash safe booster assembly comprises of the following parts:
1. Collapsible tie rod
2. Sleeve
3. Front shell
4. Valve body
5. Return spring
6. Holder
7. Adjusting screw
8. Output rod
9. Grommet (NRV)
10. Output rod retainer
11. Diaphragm plate
12. Diaphragm
13. Rear shell
14. Ratio disc
15. Poppet
16. Dust cover
17. Filter
18. Input rod
19. Circlip
20. Threshold spring
21. Poppet retainer
22. Poppet retainer spring
23. Plunger valve
24. Dilag seal
25. Reaction disc
26. NRV
27. Studs

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 diagram illustrating the present invention – Crash Safe Booster (CSB).

Figure 2 is a diagram of the present invention - Collapsible Tie rod in Booster assembly

Figure 3 is a diagram of the present invention - Collapsible Tie rod.

Figure 4 is a cross sectional diagram of the present invention - Sleeve.

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 a Crash Safe Booster (CSB) that can be used in hydraulic braking systems of cars, SUVs, MUVs & Commercial vehicles. The present invention can be used for the production of a varied range of booster assemblies, for heavy, medium and small vehicles.

Construction

As shown in Figures 1 to 4, the components in CSB are as follows:

The entire crash safe booster assembly comprises of the following parts:

1. Collapsible tie rod
2. Sleeve
3. Front shell
4. Valve body
5. Return spring
6. Holder
7. Adjusting screw
8. Output rod
9. Grommet
10. Output rod retainer
11. Diaphragm plate
12. Diaphragm
13. Rear shell
14. Ratio disc
15. Poppet
16. Dust cover
17. Filter
18. Input rod
19. Circlip
20. Threshold spring
21. Poppet retainer
22. Poppet retainer spring
23. Plunger valve
24. Dilag seal
25. Reaction disc
26. Non Return Valve
27. Studs (not visible in the cut section shown)
In a preferred embodiment of the present invention, as illustrated in Figure 1 (Booster assembly), the present invention consists of the booster which includes a Collapsible tie rod setup.

The above parts of the present invention are connected to each other as follows:
Sleeves (2) are rigidly crimped to the booster front shell (3). The collapsible tie rods (1) take an interference fit with the sleeve (2). Under extreme loading, the sleeves (2) along with the booster front shell (3) will slide over the tie rods (1). The collapsible tie rods (1) on the other side passes through diaphragm plate (11), Diaphragm (12) & the booster rear shell (13).

Working:

In a preferred embodiment of the present invention working, during a normal brake application, the reactive forces from the master cylinder is transferred through the flanges to sleeves (2). The reactive force from the master cylinder is split into half and is then transferred to the two sleeves (2) equally.

In a preferred embodiment of the present invention working, the sleeve (2) in-turn transfers the load to the tie rod (1), because of the interference between them (Sleeve & tie-rod). The interference fit created between sleeves (2) & tie-rods (1) is in such a way to withstand normal reactive forces from master cylinder, but not heavy loads such as the impact load generated during a crash.

In a preferred embodiment of the present invention working, the load is then carried through the tie rods (1) and is then transferred to the firewall, thus exhibiting the function of a normal light shell compact booster. The same applies for other loads induced in the booster shells such as the pressure load (due to vacuum) & the loads during actuation. But during a crash, the impact load generated is transferred to the master cylinder body, which is then transferred to the sleeves (2) through the master cylinder flange.

In a preferred embodiment of the present invention working, the crash load generated is sufficient enough to break the interference between tie rod (1) & sleeve (2), which in-turn makes the sleeve (2) slide over the tie-rod (1). Thus the entire load is transferred to the booster front shell (3) before being transferred to the tie rod (1). As the sleeve (2) slides, the booster front shell absorbs the impact load & crumbles, thus preventing the load from reaching the vehicle firewall.

Thus, during a frontal crash this setup prevents the brake pedal bracket from being deflected avoiding possible injuries to the driver. This also helps in isolating the pedal gear & other associated parts from the impact load thus aiding in maintaining a low repair / replacement cost. The interference between tie rod (1) & sleeve (2) is to be decided based on other vehicle parameters. The Crash Safe Booster (CSB) also help in tight packing the aggregates in engine compartment thereby giving a chance to maximize the cabin space.

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 1st day of March 2019

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