The present disclosure generally relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to a valve mechanism for a pneumatic brake system. Further, embodiments of the present disclosure disclose the construction and mechanism of an improved double check valve configured to provide a lower-pressure input to an outlet to enhance the effect of partial braking for the lift axle of a heavy-duty vehicle.
BACKGROUND
Generally, vehicles such as, but not limited to, heavy duty trucks, trailers and the like are provided with lift axles (also known as airlift axles or drop axles). Such axles are configured to be mechanically raised or lowered depending on the loading condition of the vehicle. Particularly, a lift axle is lowered to increase the weight capacity, or to distribute the weight of the cargo over more wheels. When not needed, the axle is lifted off the ground to save wear on the tires and axle and to increase traction in the remaining wheels. Generally, the heavy-duty vehicles such as trailers have pneumatic braking systems. These systems may have two or more ABS/modulator units for variably controlling the traction on the corresponding wheels. The ABS/modulator units assist in providing adequate traction to the wheels on the side of the vehicle which may go off the road during operation of the vehicle. Specifically, on surfaces like ice, gravel, sand or the like, the traction might change drastically, thereby requiring variable traction with respect to the wheels on the other side of the vehicle However, one major drawback of such systems is that for the lift axle is there is a requirement of an additional ABS unit so as to provide optimal braking effect only when the lift axle is in use and is therefore uneconomical.
With the ongoing efforts, a number of arrangements have been proposed to provide a more economical yet technically advanced pneumatic braking mechanism for lift axles. One such arrangement comprises a high pressure double check valve for providing compressed air, (or any

brake fluid) from ABS units of the main axles to the brakes on the wheels of the lift axle, thereby eliminating the requirement of a separate ABS unit for the lift axle. Such a double check valve generally comprises a casing having two inlet ports, each of which is connected with the ABS units for either side of the vehicle. Further, the double check valve has an outlet port connected with the brakes on the wheels of the lift axle. Internally, the valve comprises a valve member which is movable in the casing for selectively closing one of the two inlet ports of the valve. Upon receipt of compressed air, the valve member is pushed towards the side of low pressure input by the higher-pressure input. This results in closing of the inlet port providing the lower-pressure input and thus the high pressure compressed air is supplied to the outlet port so as to provide the braking effect to the two wheels of the lift axle. However, a major shortcoming of such high-pressure valves is that the higher-pressure air results in locking of the wheels on the side which may be on ice or any surface having a low coefficient of friction. This in turn results in improper braking effect on the trailer/vehicle.
In other words, the researchers have developed a technically advanced braking system for the lift axle of vehicles. More specifically, an improved double check valve for the brakes of the lift axle that is configured to select a lower pressure input and supply the same to wheel brakes of the lift axle so as to provide improved braking effect and overcome one or more drawbacks stated above.
SUMMARY
One or more drawbacks of conventional braking system as described in the prior art are overcome and additional advantages are provided by the improved double check valve for the brakes of the lift axle of the vehicle as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure, there is provided an improved double check valve comprising at least two inlet ports and an outlet port. The double check valve is configured to convey a lower pressure fluid from at least one of the at least two inlet ports to the

outlet port. The double check valve comprises a housing having a longitudinal bore. The longitudinal bore has a first end portion and a second end portion. An outlet port is selectively connectable with at least one of the first inlet port and the second inlet port by means of a valve member. The valve member is movably disposed in the bore between open and closed positions so as to provide lower-pressure input from one of the first and second inlet ports by closing a passage corresponding to the inlet port having the higher-pressure input.
In an embodiment of the present disclosure, the first and second inlet ports are located oppositely along a horizontal axis XX.
In another embodiment of the present disclosure, the outlet port is located at a central portion and extends along a vertical axis YY.
In an embodiment of the present disclosure, the central portion of the bore comprises a first annular rim and a second annular rim being disposed on either side of the outlet port. The first annular rim forms a first sealing face towards the first inlet port and the second annular rim forms a second sealing face towards the second inlet port.
In an embodiment, the valve member comprises first and second flanges extending radially towards the inner periphery of the bore.
In an embodiment, the first flange is disposed between the first annular rim and the first inlet port. The second flange is disposed between the second annular rim and the second inlet port.
In another embodiment of the present disclosure, a pre-determined gap is maintained between the first and second flanges and the inner periphery of the bore, thereby defining first and second passages respectively, for conveying a fluid from the corresponding first and second inlet ports to the outlet port.
In an embodiment, the first flange is configured to sealably engage with the first sealing face when the pressure of an inlet fluid from the first inlet port is higher than the pressure of an inlet fluid

from the second inlet port, closing the first passage and allowing flow of the inlet fluid from the second inlet port to the outlet port through the second passage.
In yet another embodiment, the second flange is configured to sealably engage with the second sealing face when the pressure of the inlet fluid from the second inlet port is higher than the pressure of the inlet fluid from the first inlet port, closing the second passage and allowing the flow of inlet fluid from the first inlet port to the outlet port through the first passage.
In an embodiment, the valve member is configured to remain in an equilibrium position when the pressure of the inlet fluid from the first inlet port is equal to the pressure of the inlet fluid from the second inlet port, allowing the flow of inlet fluids from both the first and second inlet ports to the outlet port through the first and second passages respectively.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent with reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1 illustrates a sectional view of the improved double check valve in accordance with the present disclosure.

Figure 2 illustrates a sectional view of a valve member of the improved double check valve of Figure 1, in accordance with the present disclosure
Figure 3 illustrates a sectional view of the improved double check valve of Figure 1, wherein the pressure of inlet fluid from the first inlet port greater than the pressure of inlet fluid from the second inlet port, according to an embodiment of the present disclosure.
Figure 4 illustrates a sectional view of the improved double check valve of Figure 1, wherein the pressure of inlet fluid from the second inlet port greater than the pressure of inlet fluid from the first inlet port, according to an embodiment of the present disclosure.
Figure 5 illustrates a sectional view of the improved double check valve of Figure 1, wherein the pressure of inlet fluid from first and second inlet ports is equal, according to an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the assemblies and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
While the invention is subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and scope of the invention as defined by the appended claims.
Before describing in detail, the various embodiments of the present disclosure it may be observed that the novelty and inventive step that are in accordance with an improved double check valve. It is to be noted that a person skilled in the art can be motivated from the present disclosure and can
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perform various modifications. However, such modifications should be construed within the scope of the invention.
Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non¬exclusive inclusion, such that an assembly, setup, system, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system or device or setup. In other words, one or more elements in the system or apparatus or device proceeded by “comprises a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly or system or apparatus. The following paragraphs explain present disclosure. The invention in respect of the same may be deduced accordingly.
Accordingly, it is an aim of the present disclosure to provide an improved double check valve for the brake system of a vehicle. Specifically, an improved double check valve configured to convey a lower-pressure input from an inlet port to an outlet so as to enhance the effect of partial braking for a lift axle of a heavy-duty vehicle.
In one non-limiting embodiment of the present disclosure, there is provided an improved double check valve comprising at least two inlet ports and an outlet port. The double check valve is configured to convey a lower pressure fluid from at least one of the at least two inlet ports to the outlet port. The double check valve comprises a housing having a longitudinal bore. The longitudinal bore has a first end portion and a second end portion. An outlet port is selectively connectable with at least one of the first inlet port and the second inlet port by means of a valve member. The valve member is movably disposed in the bore between open and closed positions so as to provide lower-pressure input from one of the first and second inlet ports by closing a passage corresponding to the inlet port having the higher-pressure input. The first and second inlet
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ports are located oppositely along a horizontal axis XX. The outlet port is located at a central portion and extends along a vertical axis YY. The central portion of the bore comprises a first annular rim and a second annular rim being disposed on either side of the outlet port. The first annular rim forms a first sealing face towards the first inlet port and the second annular rim forms a second sealing face towards the second inlet port. The valve member comprises first and second flanges extending radially towards the inner periphery of the bore. The first flange is disposed between the first annular rim and the first inlet port. The second flange is disposed between the second annular rim and the second inlet port. A pre-determined gap is maintained between the first and second flanges and the inner periphery of the bore, thereby defining first and second passages respectively, for conveying a fluid from the corresponding first and second inlet ports to the outlet port. The first flange is configured to sealably engage with the first sealing face when the pressure of an inlet fluid from the first inlet port is higher than the pressure of an inlet fluid from the second inlet port, closing the first passage and allowing flow of the inlet fluid from the second inlet port to the outlet port through the second passage. Further, the second flange is configured to sealably engage with the second sealing face when the pressure of the inlet fluid from the second inlet port is higher than the pressure of the inlet fluid from the first inlet port, closing the second passage and allowing the flow of inlet fluid from the first inlet port to the outlet port through the first passage. Additionally, the valve member is configured to remain in an equilibrium position when the pressure of the inlet fluid from the first inlet port is equal to the pressure of the inlet fluid from the second inlet port, allowing the flow of inlet fluids from both the first and second inlet ports to the outlet port through the first and second passages respectively.
The following paragraphs describe the present disclosure with reference to Figures 1 to 5. In the figures the same element or elements which have same functions are indicated by the same reference signs. For the purpose of simplicity, neither a vehicle nor a lift axle are illustrated in the figures.
Now referring to the figures, in which Figure 1 is an exemplary embodiment of the present disclosure. As shown in figure 1, the improved double check valve (100) comprises a housing (1) having a generally cylindrical configuration. However, it is understood by a person skilled in the art the shape and dimensional configuration may be variable depending on the requirement of the
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manufacturer, make of the vehicle, etc. Any modification thereof shall be within the scope of the present disclosure. The housing (1) comprises a longitudinal bore (1a) extending horizontally from a first end portion (1b) to a second end portion (1c) of the housing (1). In an embodiment, the first end portion (1b) corresponds to a first inlet port (101) of the double check valve (100) and the second end portion (1c) corresponds to a second inlet port (102) of the double check valve (100). The first and second inlet ports (101, 102) are located oppositely along a horizontal axis XX. In a non-limiting embodiment, the brake fluid of the vehicle may be compressed air. However, a person skilled in the art can be motivated to use the present double check valve for applications comprising liquid oils as well. Any such modification shall be construed to be within the scope of the present disclosure.
The first and second inlet ports (101, 102) are configured with the ABS/modular systems of the two sides of the vehicle so as to receive compressed air from the ABS units. Located intermediately between the first end portion (1b) and the second end portion (1c) is a central portion (1d) of the bore (1a). The central portion (1d) has an opening (1e) connected with an outlet port (103) of the double check valve (100). In an embodiment, the outlet port (103) extends along a vertical axis YY. The outlet port (103) may be connected with brake lines, pipes or the like to convey the compressed air received from at least one of the two inlet ports (101, 102) to the brakes of the lift axle of the vehicle. The central portion (1d) of the bore (1a) further comprises a first annular rim (2) and a second annular rim (3) being disposed on either sides of the hole (1e) to which the outlet port (103) is configured. The first and second annular rims (2, 3) have a generally spherical configuration and extend inwardly towards the horizontal axis XX. The first annular rim (2) forms an annular first sealing face (2a) towards the first inlet port (101). The second annular rim (3) forms an annular second sealing face (3a) towards the second inlet port (102). In an embodiment, the internal section of the double check valve (100) may be symmetrical about the vertical axis YY.
As shown in Figures 1 and 2, the improved double check valve (100) comprises a valve member (2) disposed movably in the bore (1a). The valve member (4) has a generally cylindrical configuration and comprises a first flange (4a) and a second flange (4b) formed at opposite ends of the valve member (4). In an embodiment, the first and second flanges (4a, 4b) may be secured
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at opposite ends of a spindle (4c) by means of threads provided on the spindle (4c). The first and second flanges (4a, 4b) extend radially towards the inner periphery of the bore (1a). In the assembled condition of the improved double check valve (100), the valve member (2) is located in the central portion (1d) of the bore (1a). The spindle (4c) of the valve member (4) is supported movably on a trough (1f) formed on the central portion (1d) of the bore (1a) such that the first and second flanges (4a, 4b) are located on opposite sides of the trough (1f). The inner diameter of the trough (1f) corresponds with an outer diameter of the spindle (4c) of the valve member (4) so as to restrict vertical displacement of the valve member (4) along axis YY. The first flange (4a) is disposed between the first annular rim (2) and the first inlet port (101) and the second flange (4b) is disposed between the second annular rim (3) and the second inlet port (102). During movement of the valve member (4) in the bore (1a) along axis XX due to difference in pressure of compressed air from first and second inlet ports (101, 102), the first flange (4a) is configured to sealably engage with the first sealing face (2a) to prevent the passage of compressed air from the first inlet port
(101) into the outlet port (103). Similarly, the second flange (4b) is configured to sealably engage with the second sealing face (3a) to prevent passage of compressed air from the second inlet port
(102) into the outlet port (103). Further, a predetermined gap (G) is maintained between the first and second flanges (4a, 4b) and the inner periphery of the bore (1a) so as to define first and second passages (P1, P2) respectively for the passage of compressed air from the first and second inlet ports (101, 102) to the outlet port (103).
Referring to Figures 3 to 5, during operation of the improved double check valve (100), when compressed air is allowed to enter into the bore (1a) from the first and second inlet ports (101, 102) simultaneously, the pressure difference between the compressed air from the first and second inlet ports (101, 102) causes the valve member (4) to move along the horizontal axis XX. As shown in Figure 3, if the pressure of the compressed air from the first inlet port (101) is more than the pressure of the compressed air from the second inlet port (102), the valve member (4) is moved slidably towards the second inlet port (102) due the higher pressure on first flange (4a). The slidable movement of the valve member (4) is restricted when the first flange (4a) abuts with the first sealing face (2a) of the first annular rim (2). In this condition, the first flange (4a) is sealably engaged with the first sealing face (2a), thereby closing the first passage (P1). This results in the second flange (4b) moving towards the second inlet port (102) such that the second passage (P2)
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is completely open. Accordingly, the lower pressure compressed air from the second inlet port (102) is conveyed to the outlet port (103) through the second passage (P2).
As shown in Figure 4, when the pressure of the compressed air from the second inlet port (102) is more than the pressure of the compressed air from the first inlet port (101), the valve member (4) is moved slidably towards the first inlet port (102) due the higher pressure on second flange (4b). The slidable movement of the valve member (4) is restricted when the second flange (4a) abuts with the second sealing face (3a) of the second annular rim (3). In this condition, the second flange (4a) is sealably engaged with the second sealing face (3a), thereby closing the second passage (P2). This results in the first flange (4a) moving towards the first inlet port (101) such that the first passage (P1) is completely open. Accordingly, the lower pressure compressed air from the first inlet port (101) is conveyed to the outlet port (103) through the second passage (P1).
Referring to Figure 5, if the pressure of the compressed air from the first inlet port (101) is equal to the pressure of the compressed air from the second inlet port (102), the valve member (4) remains in an equilibrium condition whereby both the first and second passages (P1, P2) are open for the compressed air from the first and second inlet ports (101, 102) to be conveyed simultaneously to the outlet port (103).
List of reference numerals:

100 Improved Double Check Valve
101 First Inlet Port
102 Second Inlet Port
103 Outlet Port
1 Housing
1a Bore of the Housing
1b First End Portion
1c Second End Portion
1d Central Portion
1e Hole
1f Trough
2 First Annular Rim
2a First Sealing Face
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3 Second Annular Rim
3a Second Sealing Face
4 Valve Member
4a First Flange
4b Second Flange
4c Spindle
P1 First Passage
P2 Second Passage
G Predefined Gap between First and Second Flanges and Inner Periphery of Bore
Equivalents:
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “having” should be interpreted as “having at least,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other
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modifiers, typically means at least two recitations, or two or more recitations). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

WE CLAIM

An improved double check valve (100) comprising at least two inlet ports (101, 102) and an outlet port (103), said double check valve (100) being configured to convey a lower pressure fluid from at least one of the at least two inlet ports (101, 102) to the outlet port (103), the double check valve (100) comprising;
a housing (1) comprising;
a longitudinal bore (la) having a first end portion (lb) and a second end portion (lc);
an outlet port (103) being selectively connectable with at least one of the first inlet port (101) and the second inlet port (102) by means of a valve member (4);
the valve member (4) being movably disposed in the bore (la) between open and closed positions so as to provide lower-pressure input from one of the first and second inlet ports (101, 102) by closing a passage corresponding to the inlet port having the higher-pressure input.
The double check valve (100) as claimed in claim 1, wherein the first and second inlet ports (101, 102) are located oppositely on the bore (la) along a horizontal axis XX.
The double check valve (100) as claimed in claim 1, wherein the outlet port (103) is located at a central portion (Id) and extends along a vertical axis YY.
The double check valve (100) as claimed in claim 1, wherein the central portion (Id) comprises a first annular rim (2) and a second annular rim (3) being disposed on either side of the outlet port (103); the first annular rim (2) forming a first sealing face (2a)

towards the first inlet port (101), and the second annular rim (3) forming a second sealing face (3 a) towards the second inlet port (102).
The double check valve (100) as claimed in claim 1, wherein the valve member (4) comprises first and second flanges (4a and 4b) extending radially towards the inner periphery of the bore (la).
The double check valve (100) as claimed in claims 1 and 5, wherein the first flange (4a) is disposed between the first annular rim (2) and the first inlet port (101), and the second flange (4b) is disposed between the second annular rim (3) and the second inlet port (102).
The double check valve (100) as claimed in claim 1 and 5, wherein a pre-determined gap (G) is maintained between the first and second flanges (4a and 4b) and the inner periphery of the bore (la), thereby defining first and second passages (PI and P2) respectively, for conveying a fluid from the corresponding first and second inlet ports (7a and 7b) to the outlet port (10).
The double check valve (100) as claimed in claims 1 and 5, wherein the first flange (4a) is configured to sealably engage with the first sealing face (3a) when the pressure of an inlet fluid from the first inlet port (101) is higher than the pressure of an inlet fluid from the second inlet port (102), thereby closing the first passage (PI) and allowing flow of the inlet fluid from the second inlet port (102) to the outlet port (103) through the second passage (P2).
The double check valve (100) as claimed in claims 1 and 5, wherein the second flange (4b) is configured to sealably engage with the second sealing face (3 a) when the pressure of the inlet fluid from the second inlet port (102) is higher than the pressure of the inlet fluid from the first inlet port (101), thereby closing the second passage (P2) and allowing the flow of inlet fluid from the first inlet port (101) to the outlet port (103) through the first passage (PI).

10. The double check valve (100) as claimed in claims 1 and 5, wherein the valve member (4) is configured to remain in an equilibrium position when the pressure of the inlet fluid from the first inlet port (101) is equal to the pressure of the inlet fluid from the second inlet port (102), thereby allowing the flow of inlet fluids from both first and second inlet ports (101 and 102) to the outlet port (103) through the first and second passages (PI and P2) respectively.