Description:F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10; rule 13)

1. TITLE OF THE INVENTION
A CABLE-OPERATED DISC BRAKE SYSTEM

2. APPLICANT
a. Name: Suprajit Engineering Limited
Nationality: India
Address: No. 100, Bommasandra Industrial Area, Bangalore, Karnataka, 560099, India.

Complete specification:
The following specification particularly describes the invention and the manner in which it is to be performed.
DESCRIPTION
BACKGROUND
[0001] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to being prior art by inclusion in this section.
FIELD OF THE INVENTION:
[0002] The subject matter in general relates to a braking system. More particularly, but not exclusively, the subject matter relates to a cable operated braking system with ball and screw mechanism.
DISCUSSION OF THE RELATED FIELD:
[0003] Braking is a critical aspect of vehicle operation, fundamentally ensuring safety, control, and overall functionality. It plays a pivotal role in preventing accidents, enabling drivers to navigate traffic, and facilitating timely stops when necessary. The effectiveness of a vehicle's braking system directly influences its ability to respond to sudden changes in traffic conditions or emergencies. Beyond safety, braking systems contribute to the longevity of the vehicle by minimizing wear and tear on various components. In essence, the importance of braking in a vehicle extends far beyond just stopping; it is integral to the overall reliability and security of the entire transportation experience.
[0004] Hydraulic disc braking systems have been in the market for quite some time now. The hydraulic disc braking system, though renowned for its superior performance, is not without drawbacks. One significant disadvantage is the potential mess and safety hazards associated with managing hydraulic fluids, particularly in the event of leaks. Maintenance costs are notably high due to the system's intricate design and numerous components. Additionally, issues like fluid contamination can compromise braking efficiency, necessitating frequent fluid replacements. These drawbacks highlight areas for improvement and innovation in braking technologies to address safety concerns and reduce maintenance expenses.
[0005] In an attempt to address few of the shortcoming with the hydraulic disc braking system, a novel approach to disc braking was introduced i.e., a cable-operated disc brake system.
[0006] This application deals with few structural changes in the system disclosed in patent application IN202041009257. This structural change in the design of the system offer various improvements in view of the system disclosed in IN202041009257. The detailed discussion of the structural changes and their implementation will be presented in the following sections.
SUMMARY
[0007] In one aspect of the embodiment, a cable-operated disc brake system with ball and screw mechanism is disclosed. The system comprises of a calliper housing, wherein the calliper housing defines a first space, a piston, a piston spring that is configured to be received over at least a portion of the piston, a cam lever comprising a protruding portion and a pair of split cams. At least one interfacing member is provided on the protruding portion of the cam lever, and at least one helical groove is provided on an inner surface of at least one split cam among the pair of split cams.
[0008] When the system is in assembled state, the piston along with the piston spring is configured to be received within the first space defined by the calliper housing, at least a portion of the split cams are configured to encompass at least a portion of the protruding portion of the cam lever in a manner that the at least one interfacing member on the cam lever is received within the at least one helical groove of the split cam, and at least a portion of the pair of split cams along with at least the portion of the protruding portion of the cam lever is received within the first space defined by the calliper housing, in a manner that rotational motion of the pair of split cams are restricted within the first space defined by the calliper housing.
BRIEF DESCRIPTION OF DRAWINGS
[0009] Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
[0010] FIG. 1A is a perspective view of a cable-operated disc brake system with ball and screw mechanism, in accordance with an embodiment;
[0011] FIG. 1B is an exploded view of the system with ball and screw mechanism, in accordance with an embodiment;
[0012] FIG. 2 is a perspective view of a calliper housing, in accordance with an embodiment;
[0013] FIG. 3 is a perspective view of a cam lever, in accordance with an embodiment;
[0014] FIG. 4 is a perspective view of a pair of split cams, in accordance with an embodiment; and
[0015] FIG. 5 is a cross sectional view of the assembled system, in accordance with an embodiment.
DETAILED DESCRIPTION
[0016] The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show illustrations in accordance with example embodiments. These example embodiments, which may be herein also referred to as “examples” are described in enough detail to enable those skilled in the art to practice the present subject matter. However, it may be apparent to one with ordinary skill in the art, that the present invention may be practised without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. The embodiments can be combined, other embodiments can be utilized, or structural, logical, and design changes can be made without departing from the scope of the claims. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope is defined by the appended claims and their equivalents.
[0017] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one. In this document, the term “or” is used to refer to a nonexclusive “or,” such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated.
[0018] In the embodiments that shall be discussed, components may define a circular cross section. However, the components may not be limited to circular profile and may define any geometrical cross-section or combination of different geometrical cross-sections.
[0019] Referring to FIG. 1A and 1B, a cable-operated disc brake system 100 with ball and screw mechanism is disclosed. The system 100 comprises of a calliper housing 102, a piston spring 104, a piston 106, a pair of split cams 108, a cam lever 110, a calliper cap 112, and an adjuster nut 114.
[0020] In an embodiment, the calliper housing 102 may define a first space 120, wherein the first space 120 may be longitudinally defined along a length of the calliper housing 102. The first space 120 defined by the calliper housing 102 may be of, but not limited to, a circular cross-section. The calliper housing 102 may also be configured to receive and hold brake pads on one side that may be disposed adjacent to the first space 120. The first space 120 defined by the calliper housing 102 may be provided with at least one slot 122, wherein the at least one slot 122 may be defined on an inner surface of the calliper housing 102 that defines the first slot 122, and wherein the at least one slot 122 may be defined along a length of the defined first space 120.
[0021] In an embodiment, the calliper housing 102 may be provided with an opening 202, wherein the opening 202 may be configured to provide access to brake pads through the first space 120 defined by the calliper housing 102. (refer FIG. 2)
[0022] In an embodiment, the calliper housing 102, towards one end of the defined first space 120, may be provided with a passage, wherein the passage may allow motion of the cam lever 110, when in operation.
[0023] Referring to FIG. 3, the cam lever 110 comprises of a protruding portion 302 provided on a first side of the cam lever 110, and a brake cable coupling portion 306 on a second side of the cam lever 110. The protruding portion 302 may be provided in a manner that the protruding portion 302 protrudes away from the cam lever 110. The protruding portion 302 of the cam lever 110 may define, but not limited to, a circular cross-section. The brake cable coupling portion 306 of the cam lever 110 may comprise of, but not limited to, a pair of coupling members with holes, wherein the pair of holes may be configured to engage one end of the brake cable.
[0024] In an embodiment, at least one interfacing member 304 may be provided on a surface of the protruding portion 302 of the cam lever 110. The interfacing member 304 may be, but not limited to, a ball bearing or roller bearing.
[0025] In an embodiment, the interfacing member 304 may be an external member that may be engaged on the protruding portion 302 of the cam lever 110 by any known mechanical coupling methods. The protruding portion 302 of the cam lever 110 may be provided with an indentation, wherein at least a portion of the ball bearing may be received and may be engaged by any known mechanical coupling methods.
[0026] In yet another embodiment, the interfacing member 304 may be an integral portion of the protruding portion 302 of the cam lever 110, wherein the protruding portion 302 of the cam lever 110 may be machined/manufactured in a manner that a bulge in the form of, but not limited to, a semi sphere is formed on the protruding portion 302 of the cam lever 110 which may therefore form the interfacing member 304.
[0027] Referring to FIG. 4, the pair of split cams 108 may comprise of two symmetrical C-shaped components that may be coupled together. The pair of split cams 108 may have different shapes, however, external shape of the pair of split cams 108, when coupled may be identical to the shape of the first space 120 defined by the calliper housing 102.
[0028] In an embodiment, the pair of split cams 108 may define a circular cross-section. The pair of split cams 108, when coupled, may define a second space 124 (refer FIG. 1B and FIG. 5), wherein the second space 124 may be configured to receive at least a portion of the protruding portion 302 of the cam lever 110.
[0029] In an embodiment, at least one helical groove 404 may be provided on an inner surface of at least one of the split cams among the pair of split cams 108. The helical groove 404 may define a profile identical to the interfacing member 304 on the protruding portion 302 of the cam lever 110.
[0030] In an embodiment, at least one split cam among the pair of split cams 108 may be provided with a first protruding member 402. The first protruding member 402 may protrude away from an external surface of the at least one split cam among the pair of split cams 108. The first protruding member 402 may define a profile identical to the slot 122 defined on the inner surface of the calliper housing 102 defining the first space 120 defined by the calliper housing 102.
[0031] In an embodiment, one split cam among the pair of split cams 108 may be provided with a groove 406 on one of its surface interfacing with another split cam, and another split cam among the pair of split cams 108 may be provided with a tongue member 408 on its surface interfacing with the other split cam. At least a portion of the tongue member 408 of one of the split cams may be configured to be received by at least a portion of the groove 406 provided on the other split cam, when the pair of split cams 108 are coupled.
[0032] In another embodiment, the pair of split cams 108 may be coupled using any known mechanical coupling methods like, but not limited to, jaw coupling.
[0033] Referring to FIG. 5, the second space 124 defined by the pair of split cams 108 may be configured to receive at least a portion of the protruding portion 302 of the cam lever 110 along with the interfacing member 304 in a manner that at least a portion of the interfacing member 304 on the protruding portion 302 of the cam lever 110 may be received by the helical groove 404 provided on the inner surface of at least one of the split cams among the pair of split cams 108.
[0034] In an embodiment, the piston spring 104 may be received over at least a portion of the piston 106, wherein the piston 106 along with the piston spring 104 may be received within the first space 120 defined by the calliper housing 102. The piston 106 along with the piston spring 104 may be received within the first space 120 in a manner that a first side of the piston spring 104 interfaces with an interfering surface 502 adjacent to the opening 202 of the calliper housing 102 and a second side of the piston spring 104 interfaces with an offset portion 504 of the piston 106, and the piston 106 may extend beyond the opening 202 of the calliper housing 102. The portion of the piston 106 extending beyond the opening 202 of the calliper housing 102 may be configured to engage with at least one brake pad.
[0035] In an embodiment, the piston 106 may be hollow or solid based on the requirements.
[0036] In an embodiment, the pair of split cams 108 may be received by the first space 120 in a manner that the first protruding member 402 on at least one split cams among the pair of split cams 108 may be received by the slot 122 defined on the inner surface of the calliper housing 102 defining the first space 120 defined by the calliper housing 102, wherein the protruding portion 302 of the cam lever 110 may be received within the second space 124 defined by the pair of split cams 108 when the pair of split cams 108 are received within the first space 120 of the calliper housing 102.
[0037] In an embodiment, the arrangement of the slot 122 provided on the inner surface of the calliper housing 102 defining the first space 120 of the calliper housing 102 along with the first protruding member 402 on at least one split cams among the pair of split cams 108 enables the restriction of the rotational motion of the pair of split cams 108 within the first space 120 of the calliper housing 102. The pair of split cams 108 may therefore be only allowed to move in longitudinal direction with respect to the calliper housing 102.
[0038] The arrangement of the calliper housing 102 along with the cam lever 110 and the pair of split cams 108 enables the rotational motion of the cam lever 110 to be converted into a translational motion of the pair of split cams 108 which in turn may be transferred to the piston 106 and thereafter to one of the brake pads.
[0039] In an embodiment, the adjuster nut 114 may be a nut that be configured to ensure appropriate contact force of the piston 106 on one of the brake pads. The adjuster nut 114 may be beneficial when the brake pads provided on the system 100 wear out due to frictional losses during braking, resulting in a reduction in thickness. In order to counteract the thickness loss of the brake pads, the adjuster nut 114 may be tightened, ensuring that an optimal distance is maintained between the brake pads and disk brake by pushing the piston 106 towards the brake pad.
[0040] In an embodiment, the calliper cap 112 may be provided with a through hole 506 with internal threads defined within the through hole 506. At least a portion of the adjuster nut 114 may be provided with external threads, wherein the adjuster nut 114 is received within by the through hole 506 of the calliper cap 112 in a manner that at least a portion of the adjuster nut 114 extends beyond the calliper cap 112 towards the cam lever 110, in the assembled state. As the adjuster nut 114 and the through hole of the calliper cap 112 are coupled by thread coupling, the movement of the adjuster nut 114 may be restricted within the calliper cap 112, unless an external force is applied on to it. The portion of the adjuster nut 114 extending beyond the calliper cap 112 may be configured to interface with the cam lever 110 in a manner that tightening of the adjuster nut 114 pushes the cam lever 110 towards the piston 106, which in turn may push the brake pad towards the disk brake.
[0041] In an embodiment, the adjuster nut 114 may be disposed longitudinally in the system 100.
[0042] In an embodiment, the calliper cap 112 may be engaged onto the calliper housing 102 by way of fasteners 116. It may be noted that the calliper cap 112 may be engaged to the calliper housing 102 using any known mechanical coupling methods.
[0043] In another embodiment, two interfacing members 304 may be provided on the protruding portion 302 of the cam lever 110, wherein the two interfacing members 304 may be disposed on opposite sides of the protruding portion 302.
[0044] Similarly, both the split cams of the pair of split cams 108 may be provided with one helical groove 404 each on their inner surface, wherein the helical groove 404 on each of the split cam may be configured to receive one of the interfacing members 304 provided on the protruding member of the cam lever 110.
[0045] Furthermore, the first space 120 defined by the calliper housing 102 may be provided with two slots 122, wherein the slots 122 are provided on opposite sides, and the both the split cams of the pair of split cams 108 may be provided with the first protruding member 402, wherein each of the first protruding member 402 of the split cam may be received by the slot 122 defined on the inner surface of the calliper housing 102 defining the first space 120.
ASSEMBLY AND WORKING
[0046] Having discussed the components of the system 100 in detail, the assembly and working of the system 100 will be presented in the following sections. The cable-operated disc brake system 100 disclosed in the current application is a floating calliper type brake system 100.
[0047] The system 100 may be assembled, but not limited to, in the following sequence. The piston spring 104 may be received over the piston 106, and the piston 106 along with the piston spring 104 may be received within the first space 120 defined by the calliper housing 102.
[0048] The protruding portion 302 of the cam lever 110 along with the interfacing members 304 may be encompassed by the pair of split cams 108 in a manner that the interfacing members 304 on the protruding portion 302 of the cam lever 110 are received by the helical grooves 404 provided on the pair of split cams 108. This assembly of the cam lever 110 along with the pair of split cams 108 is then received within the first space 120 defined by the calliper housing 102 in a manner that the first protruding members 402 provided on the pair of split cams 108 are received within the slots 122 provided on the inner surface of the calliper housing 102 that defines the first space 120.
[0049] The calliper cap 112 may then be engaged onto to the calliper housing 102 using the fasteners 116. The calliper cap 112 may act as a cover for the components assembled within the calliper housing 102, thereby avoiding any dust or foreign particles from entering the assembly.
[0050] The adjuster nut 114 may be disposed within the through hole of the calliper cap 112, and necessary tension may be applied onto the cam lever 110 via the adjuster nut 114 for optimum functioning of the system 100.
[0051] Lastly, an adjuster nut cap 118 may be disposed on the through hole 506 defined in the calliper cap 112 to cover the adjuster nut 114 from any dust or foreign particles from entering.
[0052] In an embodiment, the assembly of the components in a manner described above may enable the cam lever 110 to have a rotational motion and translational motion.
[0053] In an embodiment, the brake cable coupling portion 306 of the cam lever 110 and a portion of the calliper cap 112 may be connected via a compression spring (not shown in the figures) in a manner that one end of the compression spring may be engaged to the brake cable coupling portion 306 of the cam lever 110 and another end of the compression spring may be engaged to said portion of the calliper cap 112. The compression spring may be configured to offer resistance between the rotating cam lever 110 and the fixed calliper cap 112, when the cam lever 110 is rotating with respect to the calliper cap 112 during operation.
[0054] In an embodiment, when brakes are applied by a user, using a brake lever, the brake cable connected to the brake lever may pull the brake cable coupling portion 306 of the cam lever 110 towards the portion of the calliper cap 112 to which the compression spring is engaged to. As a result, the cam lever 110 may be configured to rotate within the calliper housing 102 as the brake cable continues to be pulled, and the compression spring gets compressed.
[0055] Since the protruding portion 302 of the cam lever 110 is coupled with the pair of split cams 108, and the rotational movement of the pair of split cams 108 are restricted, the rotational movement of the cam lever 110 is therefore transformed into translational motion of the pair of split cams 108, wherein the interfacing members 304 on the protruding portion 302 of the cam lever 110 interfaces and moves within the helical grooves 404 of the pair of split cams 108.
[0056] The translational movement of the pair of split cams 108 is further transferred to the piston 106, wherein the piston 106 further transfers the translational movement to the brake pad connected to the piston 106, thereby pushing the brake pad towards the disk brake on one side of the disk brake.
[0057] In case where the brake pad connected to the piston 106 on one side of the disk brake completely engages with the disk brake, and brake lever continues to pull the cam lever 110, resistance may be encountered by the calliper housing 102, and the lateral movement of the piston 106 along with the pair of split cams 108 towards the brake pad connected to the piston 106 may also be restricted as the brake pad connected to the piston 106 cannot move further due to its engagement with the disk brake, which is a fixed component on a vehicle.
[0058] Since the cam lever 110 is still in motion due to the application of brakes by the user, the only direction the piston 106 along with the pair of split cams 108 and the cam lever 110 can move is towards the calliper cap 112. Thereafter, as the piston 106 along with the pair of split cams 108 and the cam lever 110 move towards the calliper cap 112, the cam lever 110 may engage either with the adjuster nut 114 or the calliper cap 112 itself, which in turn pushes the calliper housing 102 towards the adjuster nut 114. This enables the brake pad on the other side of the disk brake to engage with the disk brake. Now, both the brake pads on the calliper housing 102 are engaged with the disk brake.
[0059] Now, when the applied brakes are released by the user, the pull force on the cam lever 110 is released, and the piston spring 104 and the compression spring are configured to come back to their original state thereby retracting the piston 106 to its original position. As the piston spring 104 and the compression spring are being recovered to their original state the force applied on the brake pads engaging with the disk brake gradually reduces, implying that the brake pads are disengaged from the disk brake.
[0060] The working of the cable operated braking system 100 disclosed in the foregoing is based on the floating calliper type braking system.
[0061] The processes described above is described as a sequence of steps. This was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, or some steps may be performed simultaneously.
[0062] Although embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the system and method described herein. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
[0063] Many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. It is to be understood that the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the personally preferred embodiments of this invention.
, Claims:CLAIMS
We claim:
1. A cable-operated disc brake system (100) with ball and screw mechanism, the system (100) comprising:
a calliper housing (102), wherein the calliper housing (102) defines a first space (120);
a piston (106);
a piston spring (104) configured to be received over at least a portion of the piston (106);
a cam lever (110) comprising a protruding portion (302); and
a pair of split cams (108), wherein,
at least one interfacing member (304) is provided on the protruding portion (302) of the cam lever (110);
at least one helical groove (404) is provided on an inner surface of at least one split cam among the pair of split cams (108), wherein when the system (100) is assembled:
the piston (106) along with the piston spring (104) is configured to be received within the first space (120) defined by the calliper housing (102);
at least a portion of the split cams are configured to encompass at least a portion of the protruding portion (302) of the cam lever (110) in a manner that the at least one interfacing member (304) on the cam lever (110) is received within the at least one helical groove (404) of the split cam; and
at least a portion of the pair of split cams (108) along with at least the portion of the protruding portion (302) of the cam lever (110) is received within the first space (120) defined by the calliper housing (102), in a manner that rotational motion of the pair of split cams (108) are restricted within the space defined by the calliper housing (102).

2. The system (100) as claimed in claim 1, wherein the cable-operated disc brake system (100) is a floating calliper type brake system (100).
3. The system (100) as claimed in claim 1, wherein the interfacing member (304) provided on the protruding portion (302) of the cam lever (110) is a ball bearing or roller bearing.
4. The system (100) as claimed in claim 1, wherein:
at least one split cam among the pair of split cams (108) is provided with a first protruding member (402) on an external surface;
at least a portion of an inner surface of the first space (120) defined by the calliper housing (102) defines a slot (122); and
the first protruding member (402) of the at least one split cam is configured to be received by the slot (122) defined within the first space (120) defined by the calliper housing (102).
5. The system (100) as claimed in claim 1, wherein one split cam among the pair of split cams (108) is provided with a groove (406) and another split cam among the pair of split cams (108) is provided with a tongue member (408), wherein the tongue member (408) of one of the split cams is configured to be received by the groove (406) of another split cam.
6. The system (100) as claimed in claim 1, wherein the system (100) comprises of an adjuster nut (114), wherein the adjuster nut (114) is configured to adjust position of the piston (106) within the calliper housing (102).
7. The system (100) as claimed in claim 1, wherein the system (100) comprises of a caliper cap (112) configured to cover the first space (120) defined by the calliper housing (102) along with the cam lever (110).
8. The system (100) as claimed in claim 1, wherein the pair of split cams (108) along with the protruding portion (302) of the cam lever (110) and the piston (106) are arranged within the calliper housing (102) in a manner that at least one surface of the pair of split cams (108) interfaces with at least one surface of the piston (106).
9. The system (100) as claimed in claim 1, wherein the pair of split cams (108) and the cam lever (110) are arranged in a manner that the rotational motion of the cam lever (110) is converted into a translational motion of the pair of split cams (108).
10. The system (100) as claimed in claim 1, wherein:
the piston (106) is configured to transfer the translational motion from the pair of split cams (108) to at least one brake pad disposed on the calliper housing (102); and
the piston spring (104) is configured to retract the piston (106) back to original position.