DESC:TECHNICAL FIELD
[001] The present invention generally relates to vehicle brake system and more particularly, the present invention relates to an automatic slack adjuster mechanism with a simplified liner wear sensing mechanism.
BACKGROUND
[002] Slack adjusters are the mechanical link between the brake chamber’s push rods and the camshaft. The entire slack adjuster works as a unit, rotating with the camshaft as the brakes are applied or released. Slack adjusters adjust the brakes to make up for wear on the lining. When the brake is applied, a rod pushes out the slack adjuster. The slack adjuster then turns the s-cam, which forcing the brake shoe apart. Then, the mechanism applies the force necessary to stop a truck. Slack adjusters are made to serve three very specific purposes. First, modern slack adjusters are designed to convert the forward linear motion of the push rod into the rotary motion of the camshaft. Slack adjusters also act as a lever that generates force and applies it to the brake discs. Finally, they provide a means of lessening the distance between the brake shoes and the brake drum, providing drivers with more responsive braking. The slack adjuster needs to be well maintained and checked regularly. Automatic Slack Adjusters for drum and disc type automotive brakes are well known. Automatic Slack Adjuster for the drum brake system controls the clearance between the drum and lining. The clearance needs to be maintained between a specific range as too less gap or too big gap will result into vehicle operational issues brake dragging or poor braking. The smaller gap results into lining wear and in extreme cases it can lead to overheating of the drum causing fire incidents. In case if gap is too large then vehicle will not be stopped within specified distance causing poor braking and accident. The clearance between the lining and drum at all wheels should be in a same range and hence consistency of the automatic slack adjusting function comes into picture. Thus, the stability of the vehicle and the driver’s response depends on how accurately and precisely each Automatic Slack Adjuster assembly works.
[003] The wear sensing mechanism in automatic slack adjuster used in commercial vehicles indicates information about wear of the brake linings to driver on dashboard, so that liner can be observed and replaced in time. Mechanism takes inputs from hex rotation of shaft which is simple in design and assembly.
[004] In prior art for the grounded Automated Slack Adjusters, the lining wear sensing mechanism is positioned in such way that it senses the rotation of “S” cam and provides details of gap between liner and drum in vehicle.
[005] Limitation of such an assembly particularly used for grounded slack is that it includes complex wear sensing mechanism mounted on slack assembly. The assembly of these parts is critical, and orientation is important. It is also critical for manufacturing as the shape, tolerances are too precise and costly.
[006] Accordingly, there is a need to provide a simplified and optimized wear sensing mechanism in automatic slack adjuster assembly, that overcomes the above-mentioned drawbacks in the prior art.

OBJECTS OF THE INVENTION
[007] An object of present invention is to provide a brake lining wear sensing mechanism for an automatic slack adjuster.
[008] Another object of the present invention is to provide a simplified mechanism for identifying brake lining wear.
[009] Still another object of the present invention is to provide a system wherein the liner wear data will be displayed on vehicle dashboard without physical checking the gap between liner and drum.
[0010] Still another object of the present invention is to provide a system for continuous monitoring of all wheel liner life and wear in vehicle.
[0011] An object of the present invention is to provide a brake lining wear sensing mechanism for an automatic slack adjuster that effectively indicates the wear status of brake linings to the driver, thereby facilitating timely replacement and maintenance.
[0012] Another object of the present invention is to provide a simplified mechanism for identifying brake lining wear, utilizing a hex shaft rotation detection system that is straightforward in design and assembly, thus reducing complexity and enhancing reliability.
[0013] Still another object of the present invention is to provide a system wherein the brake lining wear data is displayed on the vehicle dashboard, eliminating the need for physical inspection of the gap between the brake lining and the drum, thereby improving convenience and safety.
[0014] Yet another object of the present invention is to provide a system for continuous monitoring of brake lining wear across all wheels of the vehicle, ensuring consistent performance and timely alerts for maintenance.
[0015] Another object of the present invention is to achieve the aforementioned advantages by eliminating complex wear sensing mechanisms in the automatic slack adjuster assembly, thereby simplifying construction and reducing the need for small and precise components.
[0016] A further object of the present invention is to provide a robust and reliable wear sensing mechanism that is easy to manufacture, with an optimized count of parts, ensuring consistency in performance and durability.
[0017] Still another object of the present invention is to incorporate hall effect sensors and a magnet on the hex shaft to detect rotation changes, providing accurate and continuous monitoring of brake lining wear.
[0018] Yet another object of the present invention is to integrate an electronic control unit that communicates with a display unit on the vehicle dashboard, providing real-time alerts through visual or auditory signals, such as LEDs or buzzers, corresponding to specific wheels.
[0019] Another object of the present invention is to ensure that the wear sensing mechanism is robust and capable of withstanding the operational conditions of commercial vehicle drum brakes, thereby enhancing the overall reliability and lifespan of the braking system.

SUMMARY
[0020] This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in limiting the scope of the claimed subject matter. The present invention provides an automatic slack adjuster with a simple and robust wear sensing mechanism that monitors brake lining wear through the rotation of a hex shaft. The use of hall effect sensors and a magnet affixed to the hex shaft allows for continuous and accurate monitoring, while the electronic control unit and display unit ensure that the driver is promptly informed of the need for brake lining replacement. The invention achieves the advantages of easy manufacturing, reduced part count, and consistent performance by eliminating complex wear sensing mechanisms and utilizing a straightforward design.
[0021] An automatic slack adjuster for a commercial vehicle drum brake is provided in accordance with an embodiment. It consists of a housing, a hex shaft within the housing, a first hall effect sensor, and a second hall effect sensor. The first and second hall effect sensors are designed to monitor the rotation of the hex shaft, which indicates brake lining wear. This setup enables continuous monitoring of brake lining wear, ensuring constant actuator stroke even as the brake linings and drum wear.
[0022] In another embodiment, the automatic slack adjuster includes a magnet associated with the hex shaft. The first and second hall effect sensors detect the rotation of the hex shaft based on changes in the magnetic field caused by the magnet. This magnet is positioned on a hex cap affixed to the hex shaft, providing a simple yet effective means of detecting the rotation. The placement of the wear sensing mechanism along the hex shaft axis of the slack adjuster meets the requirements of simple design, robustness, and reduced part count, contributing to easy manufacturing and consistent performance.
[0023] The automatic slack adjuster also includes a casing that covers the hex shaft and the first and second hall effect sensors. This casing protects the components from environmental factors and mechanical damage, ensuring the durability and reliability of the wear sensing mechanism. The housing of the adjuster includes a worm wheel. The hex shaft is constrained between two ends of the housing by a threaded screw mechanism, providing stability and precise control over the hex shaft's movement.
[0024] Furthermore, the automatic slack adjuster includes an electronic control unit operably connected to the first and second hall effect sensors. This electronic control unit is configured to communicate with a display unit on the vehicle dashboard, providing an indication of brake lining wear. The display unit can generate an output signal in the form of a buzzer or an LED corresponding to a specific wheel, alerting the driver to the need for brake lining replacement. This feature ensures timely maintenance and enhances the safety of the vehicle.
[0025] Additionally, the first and second hall effect sensors are chosen from the group of hall effect sensors and proximity sensors. This selection offers flexibility in the design and implementation of the wear sensing mechanism, allowing for the use of different types of sensors based on specific requirements and preferences. The sensors continuously monitor the rotation of the hex shaft, providing real-time data on brake lining wear and ensuring the consistent performance of the braking system.
[0026] An additional embodiment includes a method for monitoring brake lining wear in a commercial vehicle drum brake system. The method involves detecting the rotation of a hex shaft within an automatic slack adjuster housing using a first and a second hall effect sensor, transmitting signals indicative of the detected rotation to an electronic control unit, and providing an output signal on a vehicle dashboard display unit based on the transmitted signals. The output signal is associated with a specific wheel and can be selected from the group consisting of a buzzer and an LED, ensuring that the driver is promptly informed of the brake lining wear.
[0027] In an implementation an automatic slack adjuster (100) for a commercial vehicle drum brake, is disclosed. The system comprises a housing (10). Further, a hex shaft (14) is disposed within the housing (10). A magnet (17) associated with the hex shaft (14), is provided. The magnet (17) is positioned on a hex cap (18) that is affixed to the hex shaft (14). Further a first hall effect sensor (16A), and a second hall effect sensor (16B), disposed within the housing (10). The first hall effect sensor (16A) and second hall effect sensor (16B) are configured to monitor rotation of the hex shaft (14) indicative of a brake lining wear. The first hall effect sensor (16A) and second hall effect sensor (16B) detect the rotation of the hex shaft (14) based on changes in magnetic field caused by the magnet (17).
[0028] In another implementation a method for monitoring brake lining wear in a commercial vehicle drum brake system, is disclosed. The method comprises detecting rotation of a hex shaft within an automatic slack adjuster housing using a first and a second hall effect sensor. Transmitting signals indicative of the detected rotation to an electronic control unit. Further providing an output signal on a vehicle dashboard display unit based on the transmitted signals.

BRIEF DESCRIPTION OF DRAWINGS
[0029] The detailed description is described 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 like features and components.
[0030] Figure 1, illustrates an exploded view of an automatic slack adjuster, in accordance with an exemplary embodiment of the present disclosure;
[0031] Figure 2, illustrates a schematic of the automatic slack adjuster, in accordance with the exemplary embodiment of the present disclosure;
[0032] Figure 3, illustrates a detailed schematic of a wear sensing mechanism of the automatic slack adjuster, in accordance with the exemplary embodiment of the present disclosure; and
[0033] Figure 4, illustrates a flowchart showing a method for monitoring brake lining wear in a commercial vehicle drum brake system, in accordance with the exemplary embodiment of the present disclosure

DETAILED DESCRIPTION
[0034] Some embodiments of the present disclosure, illustrating all its features, will now be discussed in detail. 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.
[0035] The present invention relates to an automatic slack adjuster for a commercial vehicle drum brake. The present invention provides a mechanism in an automatic slack adjuster used in commercial vehicles which indicates information about wear of the brake linings to driver on dashboard, so that the liner can be replaced in time. The automatic slack adjuster is designed to compensate for brake lining and drum wear to maintain a constant actuator stroke. Mechanism takes inputs from hex rotation of shaft which is simple in design and assembly. in the present invention, placement of the wear sensing mechanism along the hex shaft axis of the slack adjuster is thought to satisfy the other requirements of the assembly viz. simple design, robustness, less part count. Easy manufacturing, optimized count of parts, robust mechanism, consistency in performance are the other advantages accomplished.
[0036] In an exemplary embodiment, the present invention discloses an automatic slack adjuster for a commercial vehicle drum brake, designed to provide a mechanism that indicates brake lining wear to the driver via the vehicle dashboard. This invention aims to ensure timely replacement of brake linings by maintaining a constant actuator stroke through compensation for brake lining and drum wear. The mechanism takes inputs from the rotation of a hex shaft, which is simple in design and assembly. The placement of the wear sensing mechanism along the hex shaft axis of the slack adjuster satisfies requirements such as simple design, robustness, and reduced part count. Additional advantages include easy manufacturing, optimized part count, robust mechanism, and consistent performance, achieved by eliminating complex wear sensing mechanisms in the automatic slack adjuster assembly.
[0037] In an exemplary aspect an automatic slack adjuster is disclosed. The automatic slack adjuster may include a housing, and a hex shaft disposed within the housing. A first hall effect sensor and a second hall effect sensor further disposed in the housing. The first and second hall effect sensors may be configured to monitor rotation of the hex shaft indicative of brake lining wear. Further the automatic slack adjuster may include a magnet associated with the hex shaft. The first and second hall effect sensors may detect the rotation of the hex shaft based on changes in magnetic field caused by the magnet.
[0038] The magnet may be positioned on a hex cap that may be affixed to the hex shaft. Further a casing covering the hex shaft and the first and second hall effect sensors. In an aspect the housing may include a worm wheel and the hex shaft may be constrained between two ends of the housing by a threaded screw mechanism. In some embodiments, the first and second hall effect sensors may be configured to provide continuous monitoring of brake lining wear.
[0039] In accordance with the exemplary embodiment the automatic slack adjuster may include an electronic control unit operably connected to the first and second hall effect sensors. Further, the electronic control unit may be configured to communicate with a display unit on a vehicle dashboard to provide an indication of brake lining wear. The display unit may provide an output signal selected from the group of audios, like buzzer, and/or visual like LED.
[0040] In accordance with another exemplary embodiment, a method for monitoring brake lining wear in a commercial vehicle drum brake system, is disclosed. The method may include detecting rotation of a hex shaft within an automatic slack adjuster housing using a first and a second hall effect sensor. Further the method may include transmitting signals indicative of the detected rotation to an electronic control unit. Further providing an output signal on a vehicle dashboard display unit based on the transmitted signals.
[0041] The output signal may be associated with a specific wheel and may be selected from the group consisting of a buzzer and an LED. In some embodiments, the detecting step includes monitoring changes in a magnetic field caused by a magnet affixed to the hex shaft. The providing step includes continuous monitoring and display of brake lining may wear data/details on the vehicle dashboard.
[0042] The invention achieves the advantages by elimination of complex wear sensing mechanism on automatic slack adjuster assembly. A simple construction of wear sensing mechanism on hex shaft provides easy manufacturing by eliminating small and precise component requirements.
[0043] This present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description below:
• Housing 10
• Bush 11
• Housing cover 12
• Arm 13
• Hex shaft 14
• Grease lube 15
• First hall effect sensor 16A
• Second hall effect sensor 16B
• Magnet 17
• Hex cap 18
• Casing 19
[0044] Referring to Figure 1 to Figure 3, illustrates an automatic slack adjuster (herein after referred as, “the adjuster (100)”) with liner wear sensing mechanism. The adjuster (100) for the drum brake system of an automotive vehicle comprises a housing (10), a hex shaft (14), and two hall effect sensors (16A & 16B).
[0045] The housing (10) is covered with a metallic/housing cover (12) and includes a worm wheel. The hex shaft (14) is constrained between two ends of the housing (10) by means of a threaded screw mechanism. A wear sensing mechanism is mounted on the hex shaft (14) for monitoring the hex shaft rotation corresponding to liner wear. The wear sensing mechanism consists of a first sensor and a second sensor (16A, 16B) mounted on the hex shaft (14) with a magnet (17), a hex cap (18), and a casing (19) covering the hex shaft (14). The sensors (16A, 16B) monitor the rotation of the hex shaft (14).
[0046] In an embodiment, the sensors are selected from hall effect sensors and proximity sensors. The sensors (16A, 16B) monitor the rotation of the hex shaft (14), which corresponds to the liner wear. An electronic control unit (not shown) is operably connected to the sensors (16A, 16B) and a display unit on the vehicle dashboard for receiving and detecting signals from the sensors (16A, 16B) and providing an output signal on the display unit. The display unit is designed such that the output signal in the form of a buzzer or LED corresponding to the specific wheel is generated.
[0047] The hex shaft (14) is a critical component of the adjuster (100), designed to rotate in response to brake application and wear. The hex shaft (14) is typically made of durable materials such as steel or alloy to withstand the mechanical stresses encountered during operation. The hex cap (18) affixed to the hex shaft (14) holds the magnet (17) in place, ensuring that the magnetic field changes are accurately detected by the sensors (16A, 16B).
[0048] The casing (19) covering the hex shaft (14) and sensors (16A, 16B) is designed to protect these components from environmental factors such as dust, moisture, and mechanical damage. The casing (19) is typically made of a robust material such as high-strength plastic or metal, providing durability and longevity to the wear sensing mechanism.
[0049] The electronic control unit (ECU) connected to the sensors (16A, 16B) processes the signals indicative of the hex shaft rotation. The ECU is programmed to interpret these signals and determine the extent of brake lining wear. The ECU then communicates this information to the display unit on the vehicle dashboard, alerting the driver to the need for brake lining replacement.
[0050] In an embodiment of the present invention, the display unit on the vehicle dashboard provides continuous monitoring of brake lining wear. The display unit may include visual indicators such as LEDs or audible alerts such as buzzers to inform the driver of the brake lining condition. The output signal can be associated with a specific wheel, allowing for precise identification of the worn brake lining.
[0051] In another exemplary embodiment, an automatic slack adjuster (100), is disclosed. The automatic slack adjuster (100) may include a housing (10), and a hex shaft (14) disposed within the housing (10). A first hall effect sensor (16A) and a second hall effect sensor (16B) further disposed in the housing (10). The first (16A) and second hall effect sensors (16B) may be configured to monitor rotation of the hex shaft (14) indicative of brake lining wear. Further the automatic slack adjuster (100) may include a magnet (17) associated with the hex shaft (14). The first (16A) and second hall effect sensors (16B) may detect the rotation of the hex shaft (14) based on changes in magnetic field caused by the magnet (17).
[0052] The magnet (17) may be positioned on a hex cap (18) that may be affixed to the hex shaft (14). Further a casing (19) covers the hex shaft (14) and the first (16A) and second hall effect sensors (16B). In an aspect the housing (10) may include a worm wheel and the hex shaft (14) may be constrained between two ends of the housing (10) by a threaded screw mechanism. In some embodiments, the first (16A) and second hall effect sensors (16B) may be configured to provide continuous monitoring of brake lining wear.
[0053] In accordance with the exemplary embodiment the automatic slack adjuster (100) may include an electronic control unit operably connected to the first (16A) and second hall effect sensors (16B). Further, the electronic control unit may be configured to communicate with a display unit on a vehicle dashboard to provide an indication of brake lining wear. The display unit may provide an output signal selected from the group of audios, like buzzer, and/or visual like LED.
[0054] Figure 4 is a flowchart that describes a method for monitoring brake lining wear in a commercial vehicle drum brake system, according to some embodiments of the present disclosure. In some embodiments, at 410, the method may include detecting rotation of a hex shaft within an automatic slack adjuster housing using a first and a second hall effect sensor. At 420, the method may include transmitting signals indicative of the detected rotation to an electronic control unit. At 430, the method may include providing an output signal on a vehicle dashboard display unit based on the transmitted signals.
[0055] In some embodiments, the output signal may be associated with a specific wheel and may be selected from the group consisting of a buzzer and an LED. In some embodiments, the detecting step includes monitoring changes in a magnetic field caused by a magnet affixed to the hex shaft. In some embodiments, the providing step includes continuous monitoring and display of brake lining may wear data/details on the vehicle dashboard.
[0056] Advantages of the invention:
1. The automatic slack adjuster ensures continuous monitoring of all wheel liner life and wear in vehicle.
2. The user gets data regarding all liner wear data/details on dashboard without physical checking the gap between liner and drum.
[0057] The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the scope of the invention.
,CLAIMS:I/We claim:
1. An automatic slack adjuster (100) for a commercial vehicle drum brake, comprising:
a housing (10);
a hex shaft (14) disposed within the housing (10);
a magnet (17) associated with the hex shaft (14), wherein the magnet (17) is positioned on a hex cap (18) that is affixed to the hex shaft (14); and
a first hall effect sensor (16A), and a second hall effect sensor (16B), disposed within the housing (10);
wherein the first hall effect sensor (16A) and second hall effect sensor (16B) are configured to monitor rotation of the hex shaft (14) indicative of a brake lining wear;
wherein the first hall effect sensor (16A) and second hall effect sensor (16B) detect the rotation of the hex shaft (14) based on changes in magnetic field caused by the magnet (17).

2. The automatic slack adjuster of claim 1, comprises a casing covering (19) the hex shaft (14) and the first and second hall effect sensors (16A, & 16B).
3. The automatic slack adjuster of claim 1, wherein the housing (10) includes a worm wheel and the hex shaft (14) is constrained between two ends of the housing (10) by a threaded screw mechanism.
4. The automatic slack adjuster of claim 1, further comprising an electronic control unit operably connected to the first and second hall effect sensors (16A, & 16B).
5. The automatic slack adjuster of claim 4, wherein the electronic control unit is configured to communicate with a display unit on a vehicle dashboard to provide an indication of brake lining wear.
6. The automatic slack adjuster of claim 5, wherein the display unit provides an output signal selected from the group consisting of a buzzer and an LED corresponding to a specific wheel.
7. The automatic slack adjuster of claim 1, wherein the first and second hall effect sensors are configured to provide continuous monitoring of brake lining wear.
8. The automatic slack adjuster of claim 1, wherein the first and second hall effect sensors are selected from the group consisting of hall effect sensors and proximity sensors.
9. A method for monitoring brake lining wear in a commercial vehicle drum brake system, comprising:
detecting rotation of a hex shaft within an automatic slack adjuster housing using a first and a second hall effect sensor;
transmitting signals indicative of the detected rotation to an electronic control unit; and
providing an output signal on a vehicle dashboard display unit based on the transmitted signals.
10. The method of claim 9, wherein the detecting step includes monitoring changes in a magnetic field caused by a magnet affixed to the hex shaft.
11. The method of claim 9, wherein the providing step includes continuous monitoring and display of brake lining wear data/details on the vehicle dashboard.
Dated this on 11th Day of September, 2024

Prafulla Wange
(Agent for the Applicant)
(IN/PA-2058)