Breather cap for a diaphragm combination brake chamber

Abstract

The present invention relates to a breather cap for a diaphragm combination brake chamber, preferably used in brakes for axles of trucks, buses, trailers and semi-trailers, wherein the brake chamber is made up of an upper compartment that contains a diaphragm (3) and a spring retention mechanism (2) for the parking and emergency brake, and a lower compartment for the service brake, a breather cap (1) further being provided for equalizing the air pressure with the external environment, on movement of the diaphragm (3) of the upper chamber, in order to prevent pneumatic locking or the formation of a vacuum.

Description

Vent plug for combined diaphragm brake chamber.

[0001] The present invention relates to a breather plug for a combined diaphragm brake chamber, preferably used in axle brakes of trucks, buses, trailers and semi-trailers, the brake chamber consisting of an upper compartment containing a diaphragm and a spring retention mechanism for the parking and emergency brake, and a lower compartment for the service brake, also provided a breather plug to equalize the air pressure with the external environment when the diaphragm of the upper compartment is displaced, in order to prevent pneumatic locking or vacuum formation.

[0002] The breather plug for the brake chamber of the present invention is installed in the upper region, in the hole for the passage of the spring retaining screw, the plug being responsible for sealing and breathing the upper compartment with the external environment, as well as reducing the infiltration of dirt into the interior of the upper compartment of the brake chamber. BACKGROUND OF THE INVENTION

[0003] Air brake systems are currently widely used in freight and passenger transport vehicles, more specifically on the axles of trucks, buses, trailers and semi-trailers.

[0004] These air brake systems are typically equipped with pneumatic actuators called brake chambers, which function to activate the brake mechanism on the vehicle's wheels.

[0005] Among the models and construction forms of brake chambers, we can find single-compartment and double-compartment chambers. Single-compartment chambers are used as service brake chambers, while double-compartment chambers are used as service, parking, and emergency brake chambers, usually referred to as combined brake chambers.

[0006] In combined brake chambers, the lower compartment is generally intended for the service brake, and the upper compartment is intended for the parking and emergency brake functions of the vehicle, typically consisting of three sections: an upper, an intermediate, and a lower one. The lower compartment houses a diaphragm with an actuating rod and a return spring. The upper compartment houses a diaphragm with a spring that accumulates force when retracted, for parking and emergency braking, as well as a mechanism for retaining the spring.

[0007] Combined diaphragm brake chambers in the upper compartment are generally sealed from contact with outside air in order to prevent dirt infiltration, thus avoiding contamination and corrosion of the retaining spring.

[0008] Most commonly, these combined diaphragm chamber models are equipped with an external venting system, featuring a tube for communication and equalization of internal pressure between the compartments, thus preventing pneumatic locking and vacuum formation, ensuring proper operation.

[0009] In the current state of the art, there are various systems and devices for equalizing pressure between the compartments of these chambers, generally installed in the drive shaft tube of the parking and emergency spring, on top of the upper compartment, or in other regions. These systems present some drawbacks that can affect the proper functioning of these brake chambers, or cause deterioration during use, implying the need for periodic maintenance. These systems of the current art are also expensive and composed of several components.

[0010] Combined brake chambers that utilize breather systems with valves typically have a system composed of springs, pistons, and sealing components, which offer some resistance to allow air to pass through, generating the inconvenience of positive and negative residual pressure in the parking and emergency compartment.

[0011] US patent document 9586567B2 describes a spring brake cylinder that is provided for vehicle brake systems. It includes a spring brake piston, which is disposed in a spring brake cylinder housing and can be actuated by at least one accumulator spring, and separates a spring chamber containing the accumulator spring from a spring brake chamber of the spring brake cylinder that can be filled with air for release and can be vented for application. An air circulation device is provided for at least venting the spring chamber directly to the atmosphere. The venting device is configured as a valve device. of diaphragm having at least one elastically movable outlet diaphragm and at least one elastically movable inlet diaphragm. The inlet diaphragm and the outlet diaphragm are in a closed position in contact with an associated valve seat in the initial position of the diaphragms and, when a pressure difference between the spring chamber and the atmosphere exceeding a minimum pressure value is present, the diaphragms are moved to an open position lifted from the valve seat to increase and decrease the pressure in the spring chamber.

[0012] According to what is presented in the report described, claims and illustrations of the figures in the document above, the objective of the invention is to provide an air circulation device, ventilating the spring chamber directly to the atmosphere. Although the solution presented may solve some drawbacks of the prior art, a device such as the one presented, in the form of a plug, being made up of several sensitive moving components, may still present other drawbacks related to its use, due to atmospheric contamination by dirt, which may obstruct air circulation and stop it from working.

[0013] US patent document 6378414B1 describes an easily removable and replaceable filter cover for securing the opening of the locking tool on the top of the upper housing of an emergency brake actuator. The cover includes a plurality of ventilation holes and a membrane, preferably made of oleophobic and hydrophobic material, which allows air to pass into and out of the emergency brake chamber simultaneously. that prevent the entry of foreign materials. The invention can be easily adapted for use in any of a large number of existing emergency brake chamber assemblies at minimal cost. When the filter cover is installed, the breather openings in the housing are plugged so that all air is filtered through the membrane in the cover. In an emergency or service situation, the cover can be easily removed to allow a trapping tool to be inserted into the upper housing to release the emergency spring brake. After removal, the cover can be reused or replaced.

[0014] According to the report described and claims of the document above, the object of the invention is to provide an easily removable and replaceable filter cover for attachment to the top of the upper housing which includes a plurality of ventilation holes and a membrane through which air can enter and exit the emergency brake housing during normal use.

[0015] The drawbacks encountered in the implementation and application of the aforementioned invention are that, although the presented solution may resolve some drawbacks of the prior art, a plug-shaped device, in the various embodiments of the invention as presented, being composed of several parts and sensitive, may still present other drawbacks related to its use, due to atmospheric contamination by dirt, which may obstruct air circulation and cause it to stop working, in addition to the solution being expensive.

[0016] The solution found for the present invention, overcoming the aforementioned drawbacks, is through a brake chamber combined with an external breather plug, reducing the number of functional components. Said plug is provided with appropriate holes for air passage, located in a protected region of the plug, hindering the penetration of dirt from the external environment into the interior of the brake chamber, providing appropriate sealing to the upper hole of the chamber for the passage of the spring retaining screw.

[0017] It is therefore a necessity of the state of the art to provide a brake chamber combined with a breather plug, free from the aforementioned drawbacks, more efficient and simpler, increasing durability and reducing the risk of failures in use, thus providing a reduction in manufacturing and maintenance costs for vehicles that use this type of component. OBJECTIVES OF THE INVENTION

[0018] The main objective of the present invention is to provide a breather plug for a combined diaphragm brake chamber, making manufacturing and operation simpler, reducing costs and the risk of failure.

[0019] Another objective is to reduce the quantity and diversity of camera components.

[0020] Another objective is to reduce vehicle maintenance costs by reducing the need for downtime. DESCRIPTION OF THE FIGURES Figure 1 - Perspective view illustrating the upper part of a combined brake chamber assembled with the breather plug, object of the present invention; Figure 2 - Plan view in axial section of the combined brake chamber illustrated in Figure 1; Figure 3 - Perspective view of the upper part of the breather plug, object of the present invention; Figure 4 - Perspective view of the lower part of the breather plug illustrated in Figure 3; Figure 5 - Plan view of the upper part of the vent plug, object of the present invention; Figure 6 - Plan view in axial section of the vent plug illustrated in figure 5; Figure 7 - Front plan view of the vent plug illustrated in Figure 5. DETAILED DESCRIPTION OF THE INVENTION

[0021] In accordance with what is illustrated in the attached Figures, the present invention relates to a BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, used in brakes for axles of trucks, buses, trailers and semi-trailers, the combined brake chamber consisting of an upper compartment containing a diaphragm and a spring retention mechanism for the parking and emergency brake, and a lower compartment for the service brake, a breather plug (1) is also provided to equalize the air pressure with the external environment of the upper compartment when the diaphragm (3) is displaced, preventing pneumatic locking or vacuum formation.

[0022] The brake chamber combined in its upper compartment comprising a spring (2) and diaphragm (3), is required to prevent contamination from the external environment, corrosion and premature wear of internal components, by filtering out the penetration of contaminated air.

[0023] In one of the functions of the combined brake chamber, when the diaphragm (3) is displaced by the extension of the spring (2), the upper compartment increases its volume and, consequently, needs air infiltration, or tends to form a vacuum, generating a force opposite to the extension of the spring (2), consequently reducing part of the force accumulated by the compressed spring (2), affecting the ideal functioning of the vehicle's parking or emergency brake.

[0024] In the reverse operation, when inflation occurs with compressed air supplied by the vehicle on the opposite side of the diaphragm (3), causing the spring (2) to return together with the diaphragm (3) to the retracted spring (2) position, air compression occurs in the upper compartment, which generates a force opposite to the compression of the spring (2), resulting in a reduction of the diaphragm (3) stroke, which results in additional pressure required to release the parking or emergency brake, or even the incomplete release of the vehicle's brake system.

[0025] In both cases above, that is, when the diaphragm (3) moves, by extending or compressing the spring (2), the function of the breather plug (1) is to equalize the air pressure between the upper compartment and the outside, preventing pneumatic blockage and the formation of Vacuum, ensuring the proper functioning of the combined brake chamber.

[0026] As illustrated in Figure 2, the parking brake is activated when compressed air is exhausted on the lower side of the diaphragm (3), simultaneously activating the service brake. In this case, the breather plug (1) allows external air to enter through the orifice (4) in its body, preventing the formation of a vacuum. As the parking brake and service brake are released, the diaphragm (3) moves, compressing the air in the upper compartment, promoting exhaust through the orifice (4) to the breather, equalizing the pressure between the upper compartment (1) and the external environment.

[0027] We refer to Figures 3 to 7, illustrating the breather plug (1), in the preferred embodiment of the present invention, which is made of nitrile rubber or similar material formed by a single body, comprising a rod (9) connected at one end to a circular cap (6) provided with an inner flange (7) provided with notches (8), and at the opposite end of the rod (9) a pin (10) is provided for fixing the plug (1) in the brake chamber.

[0028] As illustrated in detail in Figure 6, the inner part of the circular cap (6) is provided with rings (11, 12), forming a space (13) between them, and an orifice (14) having the protruding ring (15). Between the inner flange (7) and the ring (11) an annular space (16) is formed, provided with at least one orifice (4) communicating with the orifice (14).

[0029] The tab (7), being annular, has the function of adapting to the surroundings of the hole (5) on the upper surface of the external body of the combined brake chamber, providing a first seal and filtering of external air, passing through the notches (8), allowing the passage of air with restriction. The rings (11, 12), and the spacing (13) have the function of providing accommodation to the hole (5), the hole (5) being suitable for the passage of the screw used as a tool for retaining the spring (2).

[0030] The plug (1) housed in the hole (5) is also responsible for sealing the upper compartment from the external environment. In other embodiments of the present invention, the breather plug (1) may have its geometric shape and appearance modified, adapting to the hole (5), being the location intended for the installation of the screw for retaining the spring (2) when necessary.

[0031] In another embodiment of the invention, the plug (1) may be supplied with an additional coin-shaped filter installed inside between the bottom of the orifice (14) and the ring (15).

[0032] In practice, the present breather plug (1) installed in the combined brake chamber provides a reduction in manufacturing and maintenance costs, due to its simplicity as it is devoid of functional components.

[0033] Another important factor is the fact that the breather plug (1), being provided with at least one orifice (4) located in the spacing (16), and the notches (8) located on the flange (7) form a restriction of air passage, reducing the infiltration of dirt and contamination of the Internal functional components in the upper compartment of the combined brake chamber.

[0034] Due to the simplicity of the breather plug (1) of the present invention and being constituted in a single body free of functional components, it offers practically no resistance in equalizing the pressure of the parking and emergency compartment, avoiding residual pressure in the upper compartment, providing improved operation.

[0035] It will be readily understood by those skilled in the art that modifications can be made to the present invention without departing from the concepts set forth in the preceding description. These modifications should be considered as included within the scope of the present invention. Consequently, the particular embodiments described in detail above are only illustrative and not limiting as to the scope of the present invention, to which the full extent of the appended claims and any and all equivalents thereof should be given.

Claims

CLAIMS 1. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, installed in the passage hole (5) of the spring retaining screw (2), of a combined brake chamber consisting of an upper compartment containing internally a diaphragm (3), a spring retaining mechanism (2) for the parking and emergency brake and a lower compartment for the service brake, characterized in that the breather plug (1) is manufactured in a single body, comprising a circular cap (6) provided in its inner part with at least one orifice (4) communicating with the orifice (14) and with a spacing (16), so as to allow air to pass through its body, equalizing the pressure between the upper compartment and the outside.

2. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, according to claim 1, characterized in that the inner part of the circular cap (6) is provided with a flap (7) equipped with notches (8).

3. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, according to claim 1 or 2, characterized in that the inner part of the circular cap (6) is further provided with rings (11, 12), forming between them the spacing (13), and an orifice (14) with a protruding ring (15).

4. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, according to any of the claims. precedents, characterized by the annular spacing (16) being formed between the inner tab (7) and the ring (11).

5. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, according to any of the preceding claims, characterized in that the plug (1) is supplied with an additional filter installed inside between the bottom of the orifice (14) and the ring (15).

6. BREATHER PLUG FOR COMBINED DIAPHRAGM BRAKE CHAMBER, according to any of the preceding claims, characterized in that the breather plug (1) comprises a rod (9) connected at one end to a circular cap (6), and at the opposite end of the rod (9) a pin (10) is provided for fixing the plug (1) to the brake chamber.

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