Claims:1. A ratchet-based auto adjuster for air disc brakes, comprising:
a piston (1) that is coupled with an at least a tappet (2);
the at least one tappet (2) that is coupled with a driver ratchet (4) by a one-way clutch mechanism, with the rotation of the at least one tappet (2) being controlled by the driver ratchet (4) and a driven ratchet (5);
an at least an overload spring (3) that facilitating to keep the ratchets in the driver ratchet (4) and the ratchets in the driven ratchet (5) are always in contact, with the drive transfer between the driver ratchet (4) and the driven ratchet (5) takes place in all the braking conditions irrespective of the adjustment; and
an at least one pin (6) that is coupled with an operating shaft (7), with: said driver ratchet (4), said driven ratchet (5), and said at least one overload spring (3) are co-axially disposed with said at least one tappet (2) and said piston (1),
with said auto adjuster being configured to monitor and automatically maintain the required clearance between the rotor of the air disc brake and friction, during every braking.
2. The ratchet-based auto adjuster for air disc brakes as claimed in claim 1, wherein the one-way clutch mechanism is an accordion spring and roller mechanism that facilitates the adjustment only in forward direction. , Description:TITLE OF THE INVENTION: RATCHET-BASED AUTO ADJUSTER FOR AIR DISC BRAKES
FIELD OF THE INVENTION
The present disclosure is related to air disc brakes. Particularly, the present disclosure is related to a ratchet-based auto adjuster for air disc brakes.
BACKGROUND OF THE INVENTION
Air disc brakes used in commercial buses and trucks are internally actuated either by twin piston or single piston, depending on the vehicle application requirement. Considering the cost and requirement of optimized specific usage, it becomes essential to develop an air disc brake with fewer internal adjusting components.
Indian Patent Application Number 201617026001 discloses a disc brake including a pivoting lever having eccentric journals, which act on a pair of tappets. The tappets are adjusted in length by rotation, and each tappet has a tappet gear. A centrally located intermediate gear is provided between the tappet gears to form a gear train synchronizing the rotation of the two tappets and, therefore, ensuring that they remain of the same length. The centrally located intermediate gear includes a socket for receiving a centrally located adjuster. The adjuster may be installed and removed from the disc brake through an aperture at the rear of the brake caliper, without any substantial disassembly of the brake and without de-synchronizing the tappets, or even interrupting the gear train between the tappets.
However, the gear trains of the tappets, the intermediate components and the adjuster parts have more losses owing to more number of components used in Adjusting and transmission. Thereby reduces the mechanical efficiency and shall have wider variation in the adjustment clearance on wear and tear.
There is, therefore, a need in the art for a ratchet-based auto adjuster for air disc brakes, which overcomes the aforementioned drawbacks and shortcomings.

SUMMARY OF THE INVENTION
A ratchet-based auto adjuster for air disc brakes is disclosed. The auto adjuster, during every braking, is configured to monitor and automatically maintain the required clearance between a rotor of the air disc brake and friction. Said auto adjuster comprises a piston that is coupled with an at least a tappet.
The at least one tappet is coupled with a driver ratchet by a one-way clutch mechanism. The rotation of the at least one tappet is controlled by the driver ratchet and a driven ratchet. An at least a pin is coupled with an operating shaft.
Said auto adjuster also comprises an at least an overload spring that facilitating to keep the ratchets in the driver ratchet and the ratchets in the driven ratchet are always in contact. The drive transfer between the driver ratchet and the driven ratchet takes place in all the braking conditions irrespective of the adjustment.
Said driver ratchet, said driven ratchet, and said at least one overload spring are co-axially disposed with said at least one tappet and said piston.
The method of working of the auto adjuster is also disclosed. The disclosed auto adjuster is: simple; cost-effective; manufacturing-friendly; and comprises fewer internal adjusting components. Further, the disclosed auto adjusted does not required any maintenance throughout the lifetime of the brake, hence no removal is required.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the cross-sectional view of an embodiment of a ratchet-based auto adjuster for air disc brakes, in accordance with the present disclosure; and
Figure 2 illustrates an embodiment of a ratchet-based auto adjuster for air disc brakes, in accordance with the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Throughout this specification, the use of the words "comprise", “have”, “contain”, and “include”, and variations such as "comprises", "comprising", “having”, “contains”, “containing”, “includes”, and “including” may imply the inclusion of an element or elements not specifically recited. The disclosed embodiments may be embodied in various other forms as well.
Throughout this specification, the phrases “at least a”, “at least an”, and “at least one” are used interchangeably.
Throughout this specification, the use of the phrase “auto adjuster” is to be construed as a set of technical components that are communicatively or operably associated with each other, and function together as part of a mechanism to achieve a desired technical result.
A ratchet-based auto adjuster for air disc brakes is disclosed (hereinafter ‘auto adjuster’). As illustrated in Figure 1 and Figure 2, an embodiment of said auto adjuster comprises: a piston (1); an at least a tappet (2); an at least an overload spring (3); a driver ratchet (4); a driven ratchet (5); an at least a pin (6); and an operating shaft (7). Said driver ratchet (4), said driven ratchet (5), and said at least one overload spring (3) are co-axially disposed with said at least one tappet (2) and said piston (1).
In an embodiment of the present disclosure, the piston (1) is coupled with the at least one tappet (2), and the rotation of the at least one tappet (2) is controlled by the driver ratchet (4) and the driven ratchet (5). The at least one tappet (2) is coupled with the driven ratchet (5) by means of a one-way clutch mechanism, such as an accordion spring and roller mechanism. This configuration allows the auto adjuster to adjust only in a forward direction. Further, due to this configuration, during forward movement, the motion transfer takes place from driven ratchet (5) to at least one tappet (2) through the one-way clutch mechanism. Alternatively, any other one-way clutches known in the art can also be used. Further, any other alternative configurations known in the art can be used and said alternative configuration may allow the auto adjuster to adjust in reverse direction as well.
In another embodiment of the present disclosure, ratchets in the driver ratchets (4) mates with the ratchets in the driven ratchet (5). The at least one overload spring (3) facilitating to keep the ratchets in the driver ratchet (4) and the ratchets in the driven ratchet (5) are always in contact. The drive transfer between the driver ratchet (4) and the driven ratchet (5) takes place in all the braking conditions irrespective of the adjustment.
In yet another embodiment of the present disclosure, the at least one pin (6) is coupled with the operating shaft (7). Said at least one pin (6) coupled with the operating shaft (7) rotates the driver ratchet (4) that is floatingly disposed on the at least one overload spring.
In yet another embodiment of the present disclosure, the driver ratchet (4) and the driven ratchet (5) with the at least one overload spring (3) facilitate the maintaining of the required wear clearance between a rotor of the air disc brake and friction, by automatically adjusting in the forward direction and slipping during an overload condition. When excess clearance is observed, the at least one pin (6) rotates the driver ratchet (4), which in turn rotates the driven ratchet (5), until the at least one overload spring (3) is compressed.
In yet another embodiment of the present disclosure, the auto adjuster, during every braking, is configured to monitor and automatically maintain the required clearance between the rotor of the air disc brake and the friction. If excess clearance is observed between the rotor of the air disc brake and the friction, drive from the driver ratchet (4) is transferred to the driven ratchet (5).
Since the at least one tappet (2) is coupled with the driver ratchet (4) through the accordion spring and roller mechanism, said at least one tappet (2) also rotates. As the at least one tappet (2) has only the rotational degree of freedom, said at least one tappet (2) linearly moves the piston (1) forward. Said forward movement of the piston (1) continues until the at least one overload spring (3) is compressed.
Due to the forward movement of the piston (1), as the friction touches the rotor of the air disc brake, the load experienced by the piston (1) gives reactional overload to the at least one overload spring (3). On subsequent compression of the at least one overload spring (3), the driver ratchet (4) slips against the driven ratchet (5) due to the static condition of the driven ratchet (5). Such coordinative actions of the at least one overload spring (3), driver ratchet (4), and the driven ratchet (5) is observed in all braking conditions, irrespective of the adjustment.
When the brake is released, during the return stroke, the driver ratchet (4) rotates along with the driven ratchet (5) and slips with the at least one tappet due to the accordion spring and roller mechanism, thereby ensuring the non-adjustment.
The disclosed ratchet-based auto adjuster for air disc brakes is: simple; cost-effective; manufacturing-friendly; and comprises fewer internal adjusting components. Further, the disclosed auto adjusted does not required any maintenance throughout the lifetime of the brake, hence no removal is required.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations and improvements without deviating from the spirit and the scope of the disclosure may be made by a person skilled in the art. Such modifications, additions, alterations and improvements should be construed as being within the scope of this disclosure.

LIST OF REFERENCE NUMERALS
1 – Piston
2 – At Least One Tappet
3 – At Least One Overload Spring
4 – Driver Ratchet
5 – Driven Ratchet
6 – At Least a Pin
7 – Operating Shaft