TECHNICAL FIELD

[0001] The present subject matter relates to a steering locking system of a vehicle. More particularly but not exclusively, the present subject matter relates to a steering system provided with mechanism to strengthen antitheft mechanism of a vehicle. BACKGROUND

[0002] Generally, in a motor vehicle a frame assembly extends rearward from a head tube. The frame assembly acts as a skeleton for the vehicle that supports the vehicle parts. A front portion of the frame assembly connects to a front wheel through one or more front suspension(s). The frame assembly extends rearward of the vehicle, where a rear wheel is connected to a frame assembly through one or more rear suspension(s). A power train e.g. an internal combustion (IC) engine is mounted to the frame assembly of the vehicle. The IC engine is functionally connected to the rear wheel, which provides the forward motion to the vehicle. Typically, plurality of panels are mounted to the frame assembly of the vehicle that covers various vehicle components. In a typical vehicle, the locking and other mechanism which aid in locking are concealed beneath such panels.

[0003] The vehicle’s anti theft mechanism is as strong as the strength of the locking mechanism and the components of steering system used for locking. Generally, a stopper welded on a head tube and actuation of plunger on a steering lock are used for locking the steering system of the vehicle. Once the steering has been rotated by pre-determined degree(s) on right or left side, the plunger is actuated which restricts further rotation of the steering of the vehicle, thus thereby securing the vehicle. [0004] To avoid theft, it is desired that the components of the locking mechanism and the steering system shall not yield and shall withstand the force applied on the locking mechanism and the steering system. Since the locking mechanism is external to the steering system, the locking mechanism needs to be fastened to the steering system using fasteners. It is observed that the fasteners and the fastening mechanism used for fastening the locking mechanism to the steering system breaks during the theft which leads to theft of vehicles.

[0005] Further, in known anti-theft locking mechanisms, plurality of brackets are used to restrict rotation of the steering system. Such an anti-theft locking mechanism uses more number of parts and requires additional assembly and sub assembly processes. This also leads to increase in overall weight of the vehicle as well as complexity & cost.

[0006] Hence, it is desired to provide an improved anti-theft mechanism for a vehicle which is easier and quicker to assemble, does not increase weight of the vehicle and uses reduced number of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 illustrates a steering system of a vehicle. [0008] Figure 2 illustrates a perspective view of steering and locking system of the vehicle according to prior art.

[0009] Figure 3a illustrates exploded view of the steering and locking system of the vehicle according to prior art. [00010] Figure 3b illustrates cross sectional view of the steering and locking system of the vehicle according to prior art.

[00011] Figure 4a illustrates the steering and locking system of the vehicle in unlocked state.

[00012] Figure 4b illustrates the steering and locking system of the vehicle in locked state while steering locked at a left side.

[00013] Figure 4c illustrates the steering and locking system of the vehicle in locked state while steering locked at a right side.

[00014] Figure 5 illustrates power flow from locking system to steering system of the vehicle during theft according to prior art. [00015] Figure 6a illustrates exploded view of the steering and locking system of the vehicle according to present invention.

[00016] Figure 6b illustrates cross sectional view of the steering and locking system of the vehicle according to present invention. [00017] Figure 7 illustrates power flow from locking system to steering system of the vehicle during theft according to present invention.

DETAILED DESCRIPTION

[00018] Generally, a two or three wheeled vehicle is provided with a front wheel and a at least one rear wheel connected to vehicle frame. A steering system is provided on the frame for converting a rotary input from rider into an amount of rotation and/or a turning force to provide direction to the front wheel with the steering system being co-axially disposed along the plane of the rotation of the wheel & the rider being symmetrically seated along the same axis. The steering system typically comprises of an upper mounting bracket, handle bar and handle holder. A typical steering mechanism is mounted at a front end of a body frame of the vehicle and is attached to the vehicle body frame through a frame member. [00019] A steering of a vehicle helps in providing direction to the vehicle during movement. If the movement of steering is restricted, it would be difficult to move the vehicle & thereby steal such a vehicle whose steering system has been locked or secured from any movement. Thus, there are various ways to restrict the rotation/movement of steering of the vehicle so as to provide and/or strengthen anti theft features. According to known steering systems, the steering system and a locking system are attached to a mounting bracket. The steering system is attached to top of the mounting bracket through handlebar holders. The locking system is attached below the mounting bracket and interacts with the steering system to lock/unlock the steering system. [00020] These and other advantages of the present subject matter would be described in greater detail in conjunction with one or more embodiments with the corresponding figures in the following description. Figure 1 illustrates a steering system of a vehicle. As shown in Figure 1, handlebar grip RH 102 and handlebar grip LH 103 are held by a rider to steer the vehicle. A brake lever RH 101 and brake lever LH 104 are used by the rider to apply front and rear brakes. In an alternate embodiment, the LH side may have a clutch lever instead of a brake lever. The handlebar grip RH 102 and handlebar grip LH 103 are located at two end sides of a handlebar 105. The handlebar 105 is mounted to an upper mounting bracket 107 using plurality of handle holders 107. The handle holder 106 attaches the handlebar 105 from top of the upper mounting bracket 107 and a lock set 108 from bottom of the upper mounting bracket 107.

[00021] Figure 2 illustrates a perspective side view of steering and locking system of the vehicle according to prior art. The locking system comprises of the lock set 108 and the means to fasten the lock set 108 to the upper mounting bracket 107. The upper mounting bracket 107 is mechanically coupled to a lower mounting bracket (not shown) and suspension system (not shown) of the vehicle. The suspension system is coupled to the front wheel of the vehicle. The handle bar 105 of the steering system provides direction to movement of the vehicle. Since, the upper mounting bracket 107 and the lower mounting bracket are also mechanically coupled to the head pipe 205, when the front wheel moves, the entire vehicle (frame) which is connected to the head pipe 205 follows the movement of the head pipe 205. The head pipe 205 is equipped with a stopper 201. The stopper 201 is a projection formed integrally to the head pipe 205. The lock set 108 comprises of a locking mechanism 203 and the lock set 108 is equipped with a plunger 202 which is actuated on operation of the lock set 108 using a key 204. Once the key 204 is operated to lock the steering system, the plunger 202 obstructs stopper 201 and thereby restricts rotation of the handle bar 105. The restriction on rotation of handle bar 105 disables maneuvering of the vehicle. The upper mounting bracket 107 and the lower mounting bracket are either directly or indirectly mechanically coupled to the head pipe 205.

[00022] Figure 3a illustrates exploded perspective view of the steering and locking system of the vehicle according to prior art. The lock set 108 includes a lock set body 307. An intermediate bracket 308 which is also a part of the lock set body 307 & is used to mount the lock set 108 to the upper mounting bracket 107. A fastener LH 305 is used to fasten a left side portion of the lock set 108 to the upper mounting bracket 107 through a sleeve LH 303 within an intermediate bracket 308. Similarly, a fastener RH 306 is used to fasten a right-side portion of the lock set 108 to the upper mounting bracket 107 through a sleeve RH 304 within an intermediate bracket 308. The sleeves (303, 304) are located between the intermediate bracket 308 and the upper mounting bracket 107. The fastener LH 305 and fastener RH 306 are guided within the sleeves (303, 304). A portion of the sleeves (303, 304) is guided through the upper mounting bracket 107. A top portion (504) of the sleeves (303, 304) is machined to get aligned, located & accommodated within a portion of the upper mounting bracket 107. This machining of the top portion (504) of the sleeves (303, 304) for enabling the sleeve to be aligned & accommodated within a portion of the upper mounting bracket 107 reduces strength of the bush. The upper cap LH 301 and upper cap RH 302 are used to cover the openings inside the sleeve from the top. This avoids entry of foreign materials such as insects, water and dust within he sleeves (303, 304). Further, it is to be noted that, according to the prior art, no portion of the sleeves (303, 304) extends above the top surface 309 of the upper mounting bracket 107.

[00023] Figure 3b illustrates cross sectional view of the steering and locking system of the vehicle according to the prior art explained in Figure 3 a. As seen in Figure 3b, according to the prior art, the sleeves (303, 304) are welded to the upper mounting bracket 107 at its lower surface (310). The sleeves (303, 304) integrated to the upper mounting bracket 107 helps in holding the locking mechanism 203 of the lock set 108 and the fastener LH 305, fastener RH 306 keep the lock set 108 attached to the upper mounting bracket 107 through the sleeves (303, 304). The operation of the key 204 actuates the locking mechanism 203 due to which the plunger 202 protrudes out of the lock set body 307.

[00024] Figure 4a illustrates the steering and locking system of the vehicle in unlocked state. The locking mechanism 203 is not actuated due to which the plunger 202 stays within the lock set body 307. Hence, no obstruction is caused to the stopper 201 and thereby rotation of the handle bar 105 is not restricted. The handle bar 105 is free to be rotated by the rider and the maneuvering of the vehicle is enabled. [00025] Figure 4b illustrates the steering and locking system of the vehicle in locked state while steering locked at a left side. The locking mechanism 203 is actuated by key 204 due to which the plunger 202 protrudes out of the lock set body 307. Hence, obstruction is caused to the stopper 201 and thereby rotation of the handle bar 105 is restricted. The rotation of the handle bar 105 is now restricted and the maneuvering of the vehicle is disabled. Similarly, Figure 4c illustrates the steering and locking system of the vehicle in locked state while steering locked at a right side.

[00026] Figure 5 illustrates power flow diagram showing force transmission from locking system to steering system of the vehicle when the stopper 201 hits the plunger 202 during theft, according to prior art. Once the locking mechanism 203 is actuated by key 204 due to which the plunger 202 protrudes out of the lock set body 307 and the vehicle’s steering system is locked either on a left side or at a right side. The obstruction is caused to the stopper 201 and thereby rotation of the handle bar 105 is restricted. A theft attempt for the vehicle at this configuration leads to impulse load created on the plunger 202 due to the stopper 201 (especially when a thief is attempting to break the locking system). Power or force flow line 503 shows the direction of transmission of impulsive forces from plunger 202 to the steering system. The force gets transmitted from the plunger 202 to the lock set body 307 and the intermediate bracket 308. The force on the intermediate bracket 308 is transmitted to the fastener LH 305 A and the fastener RH 306A. The force on the fastener LH 305 A and the fastener RH 306A is transmitted to the sleeves (303, 304). Hence, during the theft, the impulsive force is getting transmitted to the sleeves (303, 304) as well as on the weld 310. The weld 310 according to one embodiment, is performed using spot welding process. As the top portion (504) of the sleeves (303, 304) is machined, the top portion (504) of the sleeves (303, 304) becomes weak and has larger probability of breaking leading to potential stealing of the vehicle.

[00027] Figure 6a illustrates exploded perspective view of the steering and locking system of the vehicle according to present invention. Figure 6b illustrates cross sectional view of the steering and locking system of the vehicle according to present invention. The lock set 108 includes the lock set body 307. The intermediate bracket 308 which is also a part of the lock set body 307 is used to mount the lock set 108 to the upper mounting bracket 107. The fastener LH 305 is used to fasten the left side portion of the lock set 108 to the upper mounting bracket 107 through a bush LH 601. The bush LH 601 is located in between the upper mounting bracket 107 and the intermediate bracket 308. The bush LH 601 is integrally joined to the bottom surface of the upper mounting bracket 107. According to an embodiment of the present invention, bush LH 601 is integrally joined to the bottom surface of the upper mounting bracket 107 using spot welding process. Similarly, a fastener RH 306 is used to fasten a right side portion of the lock set 108 to the upper mounting bracket 107 through a bush RH 602 within an intermediate bracket 308. The bushes (601, 602) are located between the intermediate bracket 308 and the upper mounting bracket 107. The fastener LH 305 and fastener RH 306 are guided within the bushes (601, 602). A portion of the bushes (601, 602) is guided through the upper mounting bracket 107 and projects above a top surface 309 of the upper mounting bracket 107. The bush (601) is integrally joined to a top surface of upper mounting bracket (107) using projection welding process. During theft or forceful impact on steering handle bar, force is transmitted to upper mounting bracket (107) through a weld (701) which helps in reducing the impact on bush at top and helps in optimizing the thickness/strength of bush. Further, the bush is provided support at various positions across its length which helps in reducing impact on bush during theft or forceful operation of steering handle bar. The bush LH stem (60 IS) of bush (601) has a constant thickness to avoid kink formation which helps in providing strength to the bush (601).

[00028] Figure 7 illustrates power flow diagram showing flow of power from locking system to steering system of the vehicle when the stopper 201 hits the plunger 202 during theft according to present invention. The bush LH 601 comprises of a bush LH top 601T and bush LH stem 601S. Similarly, bush RH 601 comprises of a bush RH top 60 IT and bush RH stem 60 IS. The top portions 60 IT of the bushes (601LH, 601RH) protrudes and rests on the top surface 309 of the upper mounting bracket 107. The top portions 601T resting over the top surface 309 of the upper mounting bracket 107 helps in distributing and transmitting force acting on the top portions 60 IT to the upper mounting bracket 107. Due to such a configuration of the bush, & the resultant power/force distribution, the strength & durability of the locking system is enhanced without any significant increase in weight & complexity. Firstly, a better distribution of force is achieved as the forces acting on the bushes (601, 602) are distributed to a stronger part such as the upper mounting bracket 107 from different directions leading to a reduction in resultant force acting on the upper mounting bracket 107. Secondly, by eliminating power/force transmitted to a weaker section such as a bush or to a weld, the probability of breakage of the bushes (601, 602) / weld 701 is minimized which further leads to higher durability of the whole locking system & thus an improved vehicle lock system. Further, in this configuration of locking system, the swiveling of the bushes (601, 602) on its axis due to theft impact is minimized as the bush is restrained from top due to abutting of bush RH top 60 IT on the top surface 309 of the upper mounting bracket 107 and at bottom of the upper mounting bracket 107 through the weld 701.

[00029] Further, such a configuration of locking system avoids usage of heavier mounting brackets thereby avoiding increase in weight of the vehicle due to the locking system hence thereby increasing the mileage of the vehicle.

List of reference numerals:

Reference numerals Element 101 Brake lever RH 102 Handlebar grip RH

103 Handlebar grip LH

104 Brake lever LH

105 handle bar

106 handle holder

107 upper mounting bracket

108 lock set 200 Steering lock assembly 201 Stopper 202 Plunger

203 locking mechanism

204 key

205 Head pipe

301 upper cap LH

302 upper cap RH

303 Sleeve LH

304 Sleeve RH

305 fastener LH

305 fastener LH

306 fastener RH 307 Lock set body

308 intermediate bracket

501 weld

503 power flow line 601 Bush LH

602 Bush RH

701 weld

702 power flow direction 305A fastener LH top 305B fastener LH stem portion

306A fastener RH top 306B fastener RH stem 60 IS Bush LH stem

601T Bush LH top