Claims:We Claim

1. A pull type vehicle brake actuating device (1000) comprising:
? a housing body (100),
? a mounting flange (900) on the housing body (100),
? a bore (100A) in the housing body (100),
? a brake fluid inlet (110) and a brake fluid outlet (130),
? a brake fluid passage (120) in hydraulic communication with the brake fluid inlet (110) and the bore (100A),
? a piston (200) positioned within the bore (100A),
? a spring (300) positioned coaxially with the piston (200) in the bore (100A),
? a retention cap assembly (500),
? a piston movement restricting cap (600),
? a dust cover (700) externally fixed in a groove (101) at one end of the housing body (100),
? a dust cover (800) externally fixed in a groove (102) at other end of the housing body (100),
wherein,
- the piston (200) has a plurality of profiled sections at a section 200AA, a section 200AB, a groove section (200AC), a section 200AD, a spring guiding section (200AE), a spring support section (200AF), a seal accommodating groove (200AG), a seal support section (200AH), a guide portion (200AI), a support section (200AJ) and a portion 200AK;
- the bore (100A) in the housing body (100) further has a piston supporting section (100AA), an oil seal accommodating section (100AB), a working chamber (100AC), a retention cap assembly accommodating section (100AD) and an outer section (100AE);
- the brake fluid inlet (110), the brake fluid passage (120) and the brake fluid outlet (130) are in hydraulic communication with the working chamber (100AC) of the bore (100A);
- said cylindrical support section (200AB) of the piston (200) is supported on the piston supporting section (100AA) of the bore (100A);
- the piston (200) further comprises of the groove section (200AC), the second cross section portion (200AD), the spring guiding section (200AE), the seal accommodating groove (200AG), the seal support section (200AH), the guide portion (200AI), the support section (200AJ) passing through the retention cap assembly (500) and the cross section portion (200AK) on which the piston movement restricting cap (600) is fixed;
- the spring (300) positioned coaxially on the piston (200) is located between the spring support section (200AF) of the piston (200) and one end of the working chamber (100AC); and
- a connecting joint (400) mounted on the first cross section portion (200AA) of the piston (200).

2. A pull type vehicle brake actuating device (1000) as claimed in claim 1, wherein the retention cap assembly (500) comprises of a plate (501), a seal (502) accommodated in a recess (503A) in a fixing cap (503), an O-ring (504) mounted on outer surface of the fixing cap (503) and a circlip (505) holding the fixed cap within the section (100AD).

3. A pull type vehicle brake actuating device (1000) as claimed in claim 2, wherein the retention cap assembly (500) is mounted within the section (100AD) of the bore (100A).

4. A pull type vehicle brake actuating device (1000) as claimed in claim 3, wherein the piston movement restricting cap (600) is mounted on the cross section portion (200AK) of the piston (200).

5. A pull type vehicle brake actuating device (1000) as claimed in claim 4, wherein the dust cover (700) is mounted externally in a groove at (101) one end of the housing body (100) corresponding to the piston support section (100AA).

6. A pull type vehicle brake actuating device (1000) as claimed in claim 5, wherein the dust cover (800) is mounted externally in a groove (102) at other end of the housing body (100) corresponding to the outer section (100AE).

Dated this 30th day of Nov. 2020 , Description:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“PULL TYPE BRAKE ACTUATING DEVICE FOR VEHICLES”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.
FIELD OF THE INVENTION

[001] The present invention relates to braking system for motor vehicles. It more particularly relates to actuating device for braking system for two wheeled motor vehicles wherein the actuating device has a simple construction and enables provision of combined braking feature.

BACKGROUND OF THE INVENTION

[002] Conventional brake actuating mechanisms operate the front and rear wheel brakes separately. Given that weight transfer during braking causes a torque to be developed about the motor vehicles center of mass, the front wheel brake’s efficacy is normally better than that of the rear wheel brake when either of them are utilized alone. Those riders who do not feel comfortable with rapid deceleration and greater weight transfer on application of the front wheel brake alone tend to develop a habit of applying rear wheel brakes in all circumstances. Under ordinary braking conditions this does not create any problems. This becomes a problem when sudden and heavy braking is needed in an emergency braking condition. As rear wheels can start slipping sooner than the front wheels due to occurrence of weight transfer, a safety hazard is created for riders who habitually utilize their motor vehicle’s rear wheel brakes only.

[003] The safety issues arising due to habitual application of rear wheel brakes alone in all circumstances is a well-studied and well known cause of accidents. Recent regulatory changes have therefore made provision of combined braking feature in low powered two wheeled vehicles compulsory. The braking systems with combined braking feature allow for application of front wheel brakes along with the rear wheel brakes when the rider of the two wheeler has applied the rear wheel brakes only. Conventional combined braking systems are capable regulating the time difference between application of front wheel brakes and rear wheel brakes while also effectively distributing the actuating force between the front and rear wheel brakes.

[004] The regulatory compulsion of providing combined braking feature and the high price impact of its inclusion in low end two wheeled vehicles has necessitated sustained efforts for simplification of existing combined braking system. Such simplification is often aimed at facilitating reduction in production times, enabling use of semi-skilled labor force for production and facilitating use of cheaper materials in making the braking system components. Therefore there is an existing requirement of brake actuating devices that have a simpler construction, that can be manufactured using cheaper materials in less time than conventional brake actuating devices and that enable provision of combined braking feature in two wheeled vehicles more economically.

OBJECTIVES OF THE INVENTION

[005] The main objective of the invention is to provide a brake actuating device for a combined braking system.

[006] Another object of the present invention is to provide brake actuating device for use in a combined braking system that has a simpler construction.

[007] Still another objective of the present invention is to provide brake actuating device for use in a combined braking system that can be produced using cheap materials.

[008] It is yet another objective of the present invention to provide a brake actuating device for use in a combined braking system that is at least as effective as existing brake actuating devices while being cheaper than them.

SUMMARY OF THE INVENTION

[009] With above objectives in view, the current invention provides a pull type vehicle brake actuating device comprising a housing body, a mounting flange on the housing body, a bore in the housing body, a brake fluid inlet, a brake fluid inlet separating from the brake fluid inlet and a brake fluid outlet all constructed on the housing body and opening into the bore, a piston positioned within the bore, a spring positioned coaxially with the piston in the bore, a retention cap assembly, a piston movement restricting cap, a dust cover externally fixed in a groove at one end of the housing body, a dust cover externally fixed in a groove at other end of the housing body, wherein, the bore in the housing body further has a piston supporting section, an oil seal accommodating section, a working chamber, a retention cap assembly accommodating section and an outer section, the brake fluid inlet, the brake fluid inlet and the brake fluid outlet open into the working chamber of the bore, a cylindrical support section of the piston is supported on the piston supporting section of the bore, the piston further comprises of a groove section, a second cross section portion, a spring guiding section, a seal accommodating groove, a seal support section, a guide portion, a support section passing through the retention cap assembly and a third cross section portion on which the piston movement restricting cap is fixed, the spring positioned coaxially on the piston is located between a spring support section of the piston and one end of the working chamber, and a cable attachment mounting is fixed on a first cross section portion of the piston.

[0010] Typically, the retention cap assembly comprises of a plate, a seal accommodated in a recess in a fixing cap, an O-ring mounted on outer surface of the fixing cap and a circlip holding the fixed cap within the accommodating section. Typically, the retention cap assembly is fixed within the retention cap assembly accommodating section of the bore.

[0011] Typically, the piston movement restricting cap is fixed on a third cross section portion of the piston. Typically, a dust cover is mounted externally in a groove at one end of the housing body corresponding to a piston support section. Typically, another dust cover is mounted externally in another groove at other end of the housing body corresponding to the outer section of the bore in the housing body.

BRIEF DESCRIPTION OF DRAWINGS

[0012] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein

[0013] Figure 1 illustrates a schematic diagram of a combined braking system with a pull type brake actuating device in accordance with an embodiment of the present invention

[0014] Figure 2 illustrates a cut section view of a pull type brake actuating device operated via a brake pedal in accordance with an embodiment of the present invention

[0015] Figure 3 illustrates a magnified cut section view of a pull type brake actuating device in accordance with the present invention in accordance with an embodiment of the present invention

[0016] Figure 4 illustrates a magnified cut section view of a pull type brake actuating device in its fully applied condition accordance with an embodiment of the present invention

[0017] Figure 5 illustrates another schematic diagram of a combined braking system with the pull type brake actuating device in accordance with the present invention in accordance with an embodiment of the present invention

[0018] Figure 6 illustrates another cut section view of a pull type brake actuating device operated via a brake pedal in accordance with an embodiment of the present invention

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0019] Referring to Fig. 1, a pull type brake actuating device (1000) is shown to be linked with a distributing lever (1100), a single piston caliper (4000) and a master cylinder assembly (2000). The pull type brake actuating device (1000) is linked with the master cylinder assembly (2000) via a hydraulic line (2000A). The pull type brake actuating device (1000) is linked to the single piston caliper via a hydraulic line (1000A).

[0020] The distributing lever (1100) is connected with a first end of a brake actuating cable (1100B) at a connecting point (P1) (refer Fig. 2). The second end of the brake actuating cable (1100B) is connected to a lever arm (3000L) at a connecting point (E2). The lever arm (3000L) is in turn connected with a drum brake (3000) at a connection point (E1). Referring Fig. 2, the distributing lever (1100) is shown to be connected to the pull type brake actuating device (1000) at a connecting point (P3) and also to the link (5000A) at a connecting point (P2). The utilization of the distributing lever (1100) allows the brake pedal (5000)’s input to be effectively distributed between the pull type brake actuating device (1000) and the drum brake (3000). Ideally, the connecting point (P2) is located in at the center of the distributing lever (1100).

[0021] Referring Fig. 2 and 3, a pull type brake actuating device (1000) shown to be comprising of a housing body (100), a mounting flange (900) on the housing body (100), the mounting flange (900) providing at least two mounting points for attaching the pull type brake actuating device (1000) with the vehicle body, a bore (100A) in the housing body (100), a brake fluid inlet (110), a brake fluid passage (120) separating from the brake fluid inlet (110) and a brake fluid outlet (130), all constructed on the housing body (100) and opening into the bore (100A), a piston (200) positioned within the bore (100A), a spring (300) positioned coaxially with the piston (200) in the bore (100A), a retention cap assembly (500), a piston movement restricting cap (600), a dust cover (700) externally fixed in a groove at (101) one end of the housing body (100), a dust cover (800) externally fixed in a groove (102) at other end of the housing body (100). The brake fluid passage (120) is hydraulically in communication with

[0022] The bore (100A) in the housing body (100) further has a piston supporting section (100AA), an oil seal accommodating section (100AB), a working chamber (100AC), a retention cap assembly accommodating section (100AD) and an outer section (100AE). The brake fluid inlet (110), the brake fluid passage (120) and the brake fluid outlet (130) open into the working chamber (100AC) of the bore (100A). A cylindrical support section (200AB) of the piston (200) is supported on the piston supporting section (100AA) of the bore (100A). The dust cover (700) is mounted externally in a groove at (101) one end of the housing body (100) corresponding to the piston support section (100AA). Another dust cover (800) is mounted externally in a groove (102) at other end of the housing body (100) corresponding to the outer section (100AE).

[0023] The piston (200) further comprises of a groove section (200AC), a second cross section portion (200AD), a spring guiding section (200AE), a seal accommodating groove (200AG), a seal support section (200AH), a guide portion (200AI), a support section (200AJ) passing through the retention cap assembly (500) and a third cross section portion (200AK) on which the piston movement restricting cap (600) is fixed. The piston movement restricting cap (600) is fixed on a third cross section portion (200AK) of the piston (200). The spring (300) positioned coaxially on the piston (200) is located between a spring support section (200AF) of the piston (200) and one end of the working chamber (100AC), and a cable attachment mounting (400) is fixed on a first cross section portion (200AA) of the piston (200).

[0024] The profiles achieved by sectioning of the housing body (100) and the piston (200) besides serving the function determinable from their nomenclature also serve the major purpose of optimizing the overall weight of these components. This reduction in weight is achieved without diminishing there capacity to endure the stresses likely to act upon them during normal braking operation.

[0025] The retention cap assembly (500) as provided in the pull type brake actuating device (1000) comprises of a plate (501), a seal (502) accommodated in a recess (503A) in a fixing cap (503), an O-ring (504) mounted on outer surface of the fixing cap (503) and a circlip (505) holding the fixed cap within the accommodating section (100AD) (refer Fig. 3). This retention cap assembly (500) is fixed within the retention cap assembly accommodating section (100AD) of the bore (100A). The retention cap assembly (500) functions to support and retain the components positioned within the bore (100A) and the braking fluid filled within the hydraulic circuit.

[0026] When the vehicle operator operates the brake pedal (5000) alone, the input is initially transmitted only to the brake actuating cable (1100B) by the distributing lever (1100). The spring (300) prevents any movement of the piston (200) at this instant. As the brake actuating cable (1100B) is pulled the lever arm (3000L) rotates about the connection point (E1). As soon as the drum brake (3000) receiving input from the lever arm (3000L) at connection point (E1) is actuated, a threshold value of brake pedal (5000) application is reached. As soon as this threshold input value is reached the compression of the spring (300) is initiated. The piston (200) which is connected to the distributing lever (1100) via a connecting joint (400) at connecting point (P3) now begins moving left horizontally. A restoring force is setup in the spring (300) as it gets compressed due to the left horizontal movement of the piston (200).

[0027] As the piston (200) moves left horizontally in the bore (100A), the seal (205) and the seal supporting section (200AH) moves past the opening of the brake fluid inlet (110) in the working chamber (100AC). This disconnects the fluid connection between the working chamber (100AC) and the master cylinder assembly (2000) which happens at the brake fluid inlet (110) via the hydraulic line (2000A). This left horizontal movement of the piston (200) displaces the braking fluid present in the working chamber (100AC) into the hydraulic line (1000A). The pressure setup due to displacement of braking fluid into the hydraulic line (1000A) and from there into the single piston caliper (4000) initiates the braking action of the single piston caliper (4000). The piston movement restricting cap (600) comes to rest against the fixing cap (503) when the vehicle operator has fully actuated the brake pedal (5000). After the piston movement restricting cap (600) (attached to the piston (200) at the third cross section portion (200AK)) comes to rest against the fixing cap (503), the retention cap assembly (500) works to resist any further pulling force that may tend to cause additional left horizontal movement of the piston (200) (refer Fig. 4). Once restricting cap comes in contact with fixing cap , Further effort coming by pedal press will directly transferred to Rear Cable 1100B.

[0028] The dust cap (800) affixed in the groove (102) functions to deny dust an access to the outer section (100AE). This in the longer run prevents any brake fluid leakage or contamination via the gap created by dust ingestion between the support section (200AK) and the central opening in the retention cap assembly (500). The opening of the bore (100A) corresponding to the cylindrical support section (200AB) is also protected from dust by another dust cover (700). The dust covers (700 and 800) prevent scratching of the piston (200) by dust and thereby also increasing the life of the seals (210 and 510) (refer Fig. 4).

[0029] When the vehicle operator ceases operating the brake pedal (5000), the brake pedal (5000) and the distributing lever (1100) are primarily restored to their original position by restoring force provided by brake pedal (5000)’s restoring spring (not specifically indicated but attached and present between the brake pedal and the motor vehicle frame). The piston (200) is restored to its non-operative condition (as shown in Figure 3) by the restoring force provided by the spring (300). The brake actuating cable (1100B), the lever arm (3000L) and the drum brake (3000) are restored to their original position primarily under the action of internal restoring springs provided in the drum brake (3000). As the piston (200) is returning to its non-operative condition, the seal (205) and the seal supporting section (200AH) move past the opening of the brake fluid inlet (110) in the working chamber (100AC). This reestablishes the fluid connection between the working chamber (100AC) and the master cylinder assembly (2000). This reestablishment of fluid connection allows the braking fluid to flow into the working chamber (100AC) from the master cylinder assembly (2000) thereby preventing a vacuum from being setup in the hydraulic circuit leading up to the single piston caliper (4000) via the brake fluid outlet (130) and the hydraulic line (1000A). The brake fluid passage (120) diverging from the brake fluid inlet (110) maintains a fluid connection at all times with the space between the support section (200AH) and the inner face the plate (501). This prevents setting up of any adverse pressure in this space that may resist the movement of the piston (200).

[0030] In an alternate mode of operation of the combined braking system as shown in Fig 1, when the master cylinder assembly (2000) is operated alone, the brake fluid is displaced from the master cylinder assembly (2000) via the hydraulic line (2000A) into the working chamber (100AC) and then via the hydraulic line (1000A) into the single piston caliper (4000). This directly operationalizes the single piston caliper (4000) without applying the drum brake (3000). In this mode of brake operation the retention cap assembly (500) works to prevent any brake fluid leakage through it.

[0031] In another mode of operation of the combined braking system as shown in Fig. 1, when both the master cylinder assembly (2000) and the brake pedal (5000) are operated by the vehicle operator, the drum brake (3000) is applied primarily under the actuation force provided by the brake pedal (5000) that is transmitted from it via the link (5000A), the distributing lever (1100), the brake actuating cable (1100B) and the lever arm (3000L). As fluid connection is constantly maintained between the master cylinder assembly (2000) and the working chamber (100AC) in this mode of operation, the extent of left horizontal movement of the piston (200) under force transmitted to it via the distributing lever (1100) is diminished. A resultant pressure created by the limited left horizontal displacement of the piston (200) and the operation of the master cylinder assembly (2000) is transmitted to the single piston caliper (4000) via the brake fluid outlet (130) and the hydraulic line (1000A). Thereby greater braking force is achieved at the single piston caliper (4000) in this mode of operation. Here again, the retention cap assembly (500) works to prevent any brake fluid leakage through it.

[0032] The pull type brake actuating device (1000) can also be utilized in a setup as disclosed by the Fig. 5. The schematic diagram (refer Fig. 5) shows a combined braking system in which the brake inlet port (110) of the pull type brake actuating device is connected to a brake fluid reservoir (1500) via a hydraulic line (1500A). In this combined braking system the master cylinder assembly (2000) is directly connected to one inlet port of a multi-piston caliper (6000) via its hydraulic line (2000A). The brake fluid outlet (130) of the pull type brake actuating device (1000) is also connected to another inlet port of the multi-piston caliper (6000). Referring Fig. 5, the distributing lever (1100) is shown to be connected with the brake pedal (5000), the pull type brake actuating device (1000) and the drum brake (3000) in a manner similar to that of the combined braking system as indicated by Fig. 1.

[0033] The connection between the pull type brake actuating device (1000) and the hydraulic line (1500A) is achieved by utilizing a connector (1500CO), an O-ring (1500O) and a circlip (1500C) (refer Fig. 6). Utilizing a connector (1500C) may normally require the bore diameter of the brake fluid inlet (110) and the alignment of the brake fluid passage (120) to be suitably adjusted in the housing body (100) to achieve a leak proof and sturdy connection between the connector (1500CO) and the brake fluid inlet (110).

[0034] The working of the pull type brake actuating device (1000) in the combined braking system shown in Fig. 5 is same as that of described for combined braking system indicated by Fig. 1 when only brake pedal (5000) is operated. The master cylinder assembly (2000) being directly connected to the multi-pot caliper (6000) can directly actuate it without utilizing the hydraulic circuit leading up to the multi-pot caliper (6000) from the pull type brake actuating device (1000). In the combined braking system as per schematic shown in Fig. 5, when both the master cylinder assembly (2000) and the pull type brake actuating device (1000) are operated together, the multi-pot caliper (6000) receives two separate pressure inputs instead of one single resultant pressure input via the pull type brake actuating device (1000). The piston (200)’s left horizontal movement in this case is not resisted by the pressure setup by the master cylinder assembly (2000) as the hydraulic circuits leading up to the multi-pot caliper (6000) from the master cylinder assembly (2000) and the pull type brake actuating device (1000) are isolated from each other. The benefit of using the pull type brake actuating device (1000) in a combined braking system as per schematics shown in Fig. 5 is that the braking system on the whole becomes more resilient. Any damage to the hydraulic line (1000A) which drains out the braking fluid from the pull type brake actuating device (1000) still allows at least limited braking to happen through the multi-pot caliper (6000) via operation of the master cylinder assembly (2000).

[0035] The advantages of the pull type brake actuating device (1000) as utilizable in combined braking systems shown in Fig. 1 and Fig 5. are:
- It has a simple construction that allows it to be easily manufactured in large numbers without using any particularly costly material or highly skilled workforce.
- It has a simple construction that makes it very durable enabling it use for a long duration of time without needing any major repair.
- It provides a braking performance that is at par as compared with the existing brake actuating devices.

[0036] The disclosed invention therefore achieves the objective of providing an easy to manufacture and economic brake actuating device for use in a combined braking system. While the use of pull type brake actuating device (1000) has been described in context of only two probable schematics of combined braking system (refer Fig. 1 and Fig. 5) it is not hard for a person skilled in the art to imagine and put it to use in any other schematic of a combined braking system where at least one input force can be transmitted and applied to the piston (200) and at least one output can be obtained and utilized from the brake fluid outlet (130). The description provided must hence not been seen to be limiting the scope of the invention in this context.