DESC:FIELD OF THE INVENTION
The present invention relates to locking mechanism. More particularly, the present invention relates to a locking mechanism & construction of telescopic steering column for all off highway & light commercial vehicles.

BACKGROUND OF THE INVENTION
Objective function of the telescopic column is to adjust height of the steering wheel and lock in desired position. The Current available system globally in the passenger car is a cam type locking mechanism which enables the locking within clamp bracket and slotted bracket tied along with stud and lock nut tightened other side of cam. This solution provides progressive height adjustment. Upper column tube and lower column tube are designed to slide over other.

The locking mechanism of cam actuator is available with a male cam fixed and female cam sliding over male fixed cam, during this actuation the cam designed in a way the fixed cam displaces apart to clamp the bracket welded to upper column with main bracket with slotted provision for cam set and bearing this creates frictional load at interface locations on clamp bracket on outer tube and main bracket thus this construction retain the height at which telescopic column is locked.

US8505408B2 discloses an adjustable steering column assembly. An adjustable steering column assembly includes a fixed rack secured to a first portion and a moving rack secured to a second portion, which are releasably engaged by a clamp mechanism to permit relative movement there between. The fixed rack comprises two rows of teeth spaced apart from one another and extending towards. The moving rack also comprises two rows of teeth which extend away from each other. A clamp engaging means moves the moving rack into and out of engagement with the fixed rack. The teeth on the two racks are offset relative to one another. The mechanism is further arranged so that when if a tooth on tooth event occurs the fixed rack interacts with the moving rack to cause the moving rack to move sideways to permit the teeth to become inter-engaged when the mechanism finally reaches the locked position. However this patent relates to telescopic height adjustment using Rack male and female and not related to locking mechanism.

EP0592278B1 discloses a device for locking an adjustable steering column for example of an automotive vehicle and steering column unit comprising such a device. Locking mechanism has 2 flanges with pockets reducing through center of the flange for ball movement. Tie rod connecting handle housing and flange with pocket and ball set. Tied through other end with bearing and washer and locked with nut. Protective housing with handle lever as sing le casing. This patent relates to locking mechanism with ball and flat cam. This patent relates to locking mechanism with actuation of female and male cam with open ended pocket for 2 balls movement. This patent relates to thrust bearing and washer without enclosure and tied with nut. Tie bolt holds the two flat cams with ball and thrust bearing & washer nut.

EP1170194B1 relates to a device for adjusting the reach and height of the steering column of a vehicle. A device on a steering column for motor vehicles for adjusting the length and height of the steering column, comprising a bracket part (1) which is securable to the chassis of the vehicle, a guide part (2) in which a clamping bolt (7) is mounted so as to be displaceable in the axial direction of the clamping bolt (7) which projects through an opening (71) in the bracket part (1) and which, for adjusting the height of the steering column, is displaceable in relation to the bracket part (1) together with the guide part (2) perpendicularly to its axial extent and substantially perpendicularly to the axial extent of the steering spindle (5), and a casing tube (3) provided with a slot (38) through which the clamping bolt (7) projects and which extends in the axial direction of the steering column, the casing tube (3) being displaceable in the axial direction of the steering spindle (5) for adjusting the length of the steering column, wherein a clamping means is provided which comprises the clamping bolt (7) and a clamping member (9) and by means of which a first fixing means for the height adjustment of the steering column and a separate, second fixing means for the length adjustment of the steering column are jointly openable and closable, characterized in that the first fixing means is formed as a frictional connection and comprises a lamella stack (15) with large and small lamellae (16, 17) which alternate in the lamella stack and through which the clamping bolt (7) extends and of which the large lamellae (16) are variable in their mutual spacing in or on the bracket part (1), but are non-displaceably mounted in the direction of the height adjustment of the steering column and have an inner aperture (18) for allowing the displacement of the clamping bolt (7) in relation to the bracket part (1) in the open state of the first fixing means for the height adjustment of the steering column, and of which the small lamellae (17) are displaceable in the axial direction of the clamping bolt (7), but are non-displaceably mounted in relation to the clamping bolt (7) in the direction of the height adjustment of the steering column and are displaced in relation to the large lamellae (16) in the event of displacement of the clamping bolt (7) in relation to the bracket part (1) in the open state of the first fixing means, wherein the lamella stack (15) is arranged between first (13) and second (76) clamping jaws, between which the lamella stack is clamped in the closed state of the first fixing means and between which spring members (30, 52) act which space the clamping jaws (13, 76) apart in the open state of the first fixing means, and in that, in order to reduce the bearing clearance in the event of a great adjusting force of the steering column in the direction of the height adjustment in the closed state of the first fixing means, a means for resiliently acting upon the large lamellae (16) and preferably also the small lamellae (17) in the direction of the height adjustment of the steering column is provided, wherein consecutive large lamellae (16) and optionally also consecutive small lamellae (17) are acted upon alternately in the upwards and downwards directions or also in alternating diagonal upwards and downwards directions. This patent relates to locking of steering column with a pin actuated by shim spring. Male and female cam sliding to actuate pin.

US20020083784A1 relates to a ball ramp actuator for locking mechanism. Two cam plates each have at least one groove providing a non-circumferential ball ramp. The ball ramp of the second cam plate intersects with the ball ramp of the first cam plate when viewed axially. At least one ball is positioned between the first and second cam plates, in the grooves of the first and second cam plates. The ball is biased radially to ensure that the ball follows the non-circumferential ball ramps of both cam plates in response to relative rotation of the two cam plates. Two cam plates each have at least one groove providing a non-concentric ball ramp. Ball Retainer placed between the cam plates. This patent relates to ball ramp locking mechanism not specific to any application, instead claim as specific telescopic application. Male and female plate with ball pockets needs a plate in middle holding the ball in circumference.

Limitations:
• Design is not concealed to mud and dust ingress, thus not making this suitable for Off-road & Light commercial vehicle applications.
• Clamping lever effort is high.
• Cost of manufacturing the Cams is high.

Accordingly, there exists a need for a vibration resisting rigid locking mechanism for telescopic steering column for Off-road & Light commercial vehicles.

OBJECTS OF INVENTION
It is the primary object of the present invention to provide a ball & ramp locking mechanism for telescopic steering column for all Off-highway and Light Commercial vehicles.

It is another object of the present invention to provide an effective locking mechanism for height adjustment to the Telescopic steering column for comfort of driver at various seat adjustments.

It is another object of the present invention to provide a proprietary design of locking mechanism to lock the position of column.

It is another object of the present invention to provide a simplified locking mechanism which enhances high retention load during operation.

It is another object of the present invention to provide a smooth actuation of lever and reduced actuation effort.

SUMMARY OF THE INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

It is the primary aspect of the present invention to provide a ball and ramp locking mechanism of telescopic steering column for vehicles, comprising:
a main bracket with one or more square slots;
an upper column assembly;
a lower column assembly;
a clamp bracket with one or more slots;
a stationary static ramp housing with one or more pockets;
a rotatable dynamic ball seat housing;
a stationary bearing housing comprises of a thrust bearing and a washer plate;
a tie rod;
two or more steel balls; and
a clamp bolt assembly comprises of a lever handle and a lock nut,
wherein during actuation, the dynamic ball seat housing displaces apart and pulls the head of the clamp bolt away from the main bracket, to create clamping load on the main bracket over the clamp bracket to perform clamping function, and the ball and ramp locking mechanism locks the position of the telescopic steering column,
the static ramp housing and the dynamic ball seat housing with circumferential pockets are milled for ball location and movement, and
the external load acting on the upper column assembly is given by a clamp bolt on the clamp bracket parallel to the direction of the slit opening, and the slit in the outer column tube compress and collapses over the lower column tube of lower column assembly to perform locking function with the double frictional load.

It is another aspect of the present invention, wherein the main bracket with the square slot positions the static ramp housing and the bearing housing both in a same line and rotation of these members are arrested through the square slot.

It is another aspect of the present invention, wherein the clamp bracket connects the static ramp housing and the bearing housing through a clamp bolt passing through the slot for height adjustment preferably between 20 to 100mm.

It is another aspect of the present invention, wherein the static ramp housing comprises pockets for the steel ball at clamping and unclamping position around a pitch diameter connected through a sliding ramp.

It is another aspect of the present invention, wherein the dynamic ball seat housing comprises pockets for the steel ball positioned around a pitch diameter equivalent to the static ramp housing.

It is another aspect of the present invention, wherein the steel balls are placed in between the pockets provided on the static ramp housing and the dynamic ball seat housing.

It is another aspect of the present invention, wherein the washer plate in bearing housing on other side of the main bracket is tied to the clamp bolt with a lock nut, squeezed to bolt.

It is another aspect of the present invention, wherein the bearing housing is positioned in line with the static ramp housing in the main bracket providing the space for the thrust bearing and the washer plate.

It is another aspect of the present invention, wherein the clamp bolt assembly connects an actuating lever and the dynamic ball seat housing through a spline.

It is another aspect of the present invention, wherein the tie rod and the dynamic housing is connected through the spline moving the ball over the static ramp housing, tied through other end with the washer housing with the bearing housing and the washer plate locked with the lock nut.

It is another aspect of the present invention, wherein the static ramp housing and the dynamic ball seat housing protects the locking mechanism.

It is another aspect of the present invention, wherein the main bracket base is mounted on a tilt carriage of the vehicle below the dashboard.

It is another aspect of the present invention, wherein the clamp bracket is welded to the upper column assembly.

BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the features, advantages and objects of the invention, as well as others which will become apparent, may be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only a preferred embodiment of the invention and is therefore not to be considered limiting of the invention's scope as it may admit to other equally effective embodiments.
Figure 1: illustrates perspective view of the full assembly of telescopic column with upper and lower column assembly according to one embodiment of the present invention.
Figure 2: illustrates front view of the elements of upper and lower column assembly according to another embodiment of the present invention.
Figure 3: illustrates the cross sectional view of the locking mechanism parts and construction according to another embodiment of the present invention.

DESCRIPTION FOR DRAWINGS WITH REFERENCE NUMERALS:
(1.0) Upper column assembly
(2.0) Lower column assembly
(1.1) Clamp bracket
(2.1) Main bracket
(3.1) Stationary static ramp housing
(3.2) Rotatable dynamic ball seat housing
(3.5) Stationary bearing housing
(3.6) Thrust bearing
(3.7) Washer plate
(3.9) Steel balls
(4.0) Clamp bolt assembly
(4.1) Lever handle
(4.2) Lock nut

DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to locking mechanism & construction of the Column assemblies. More particularly, the present invention relates to a locking mechanism for telescopic steering column for all off-highway and Light commercial vehicles.

Referring to Figure 1, perspective view of the full assembly of telescopic column with upper and lower column assembly is illustrated. Referring to Figure 2, front view of the elements of upper and lower column assembly is illustrated. Referring to Figure 3, the cross sectional view of the locking mechanism parts and construction is illustrated. The ball and ramp locking mechanism of telescopic steering column for vehicles, comprises a main bracket (2.1) with one or more square slots, an upper column assembly (1.0), a lower column assembly (2.0), a clamp bracket (1.1) with one or more slots, a stationary static ramp housing (3.1) with one or more pockets, a rotatable dynamic ball seat housing (3.2), a stationary bearing housing (3.5) comprises of a thrust bearing (3.6) and a washer plate (3.7), a tie rod, two or more steel balls (3.9) and a clamp bolt assembly (4.0) comprises of a lever handle (4.1) and a lock nut (4.2). During actuation, the dynamic ball seat housing (3.2) displaces apart and pulls the head of the clamp bolt away from the main bracket (2.1), to create clamping load on the main bracket (2.1) over the clamp bracket (1.1) to perform clamping function, and the ball and ramp locking mechanism locks the position of the telescopic steering column. The static ramp housing (3.1) and the dynamic ball seat housing (3.2) with circumferential pockets are milled for ball location and movement. The external load acting on the upper column assembly (1.0) is given by a clamp bolt on the clamp bracket (1.1) parallel to the direction of the slit opening, and the slit in the outer column tube compress and collapses over the lower column tube of lower column assembly (2.0) to perform locking function with the double frictional load.

The main bracket (2.1) with the square slot positions the static ramp housing (3.1) and the bearing housing (3.5) both in a same line and rotation of these members are arrested through the square slot. The clamp bracket (1.1) connects the static ramp housing (3.1) and the bearing housing (3.5) through a clamp bolt passing through the slot for height adjustment preferably between 20 to 100mm. The static ramp housing (3.1) comprises pockets for the steel ball (3.9) at clamping and unclamping position around a pitch diameter connected through a sliding ramp. The dynamic ball seat housing (3.2) comprises pockets for the steel ball (3.9) positioned around a pitch diameter equivalent to the static ramp housing (3.1). The steel balls (3.9) are placed in between the pockets provided on the static ramp housing (3.1) and the dynamic ball seat housing (3.2). The washer plate (3.7) in bearing housing (3.5) on other side of the main bracket (2.1) is tied to the clamp bolt with a lock nut (4.2), squeezed to bolt. The bearing housing (3.5) is positioned in line with the static ramp housing (3.1) in the main bracket (2.1) providing the space for the thrust bearing (3.6) and the washer plate (3.7). The clamp bolt assembly (4.0) connects an actuating lever and the dynamic ball seat housing (3.2) through a spline. The tie rod and the dynamic housing (3.2) is connected through the spline moving the ball over the static ramp housing (3.1), tied through other end with the washer housing with the bearing housing (3.5) and the washer plate (3.7) locked with the lock nut (4.2). The static ramp housing (3.1) and the dynamic ball seat housing (3.2) protects the locking mechanism. The main bracket (2.1) base is mounted on a tilt carriage of the vehicle below the dashboard. The clamp bracket (1.1) is welded to the upper column assembly (1.0).

The main bracket base is mounted on a Tilt carriage of the vehicle below dashboard. The clamp bracket is a separate child part welded to Upper column welding sub-assembly. The proposed mechanism accommodates any change height difference can be achieved upon necessary changes to mating parts. All components are preferably made from steel. A slit is a feature provided on the upper column tube, this tend to contract or collapse on application of external load, in the present invention, the external load is given by the clamp bolt on clamp bracket parallel to the direction of slit opening, thus the slit contracts and grips on the lower column tube. The steel balls are placed in between the pockets provided on the static ramp housing and Dynamic ball seat housing.

The locking mechanism is provided with a static ramp housing (3.1) is a stationary member positioned in the main bracket (2.1), this housing (3.1) has pockets for the ball at clamping and unclamping position connected through a sliding ramp. Another member of actuation is a dynamic ball seat housing (3.2) is a rotating member with a single pocket to drive the ball over the sliding pocket to clamp / unclamp position of static ramp housing (3.1). The steel balls (3.9) are placed in-between the static ramp housing (3.1) and dynamic ball seat housing (3.2). All these parts are tied across with a splined clamp bolt assembly (4.0) on the main bracket (2.1).

During this actuation the dynamic ball seat housing (3.2) displaces apart from the static ramp housing (3.1), by means of a clamp bolt passing through the clamp bracket (2.1), pulls the bearing housing assembly (3.5) on other side to clamp the clamp bracket (1.1) of upper column assembly (1.0) with lower column assembly (2.0). Thus, the frictional load is created and then converted as locking function.

During this locking, load acting on upper column assembly (1.0) with Slit provided in the outer column tube contracts over the lower column tube of lower column assembly (2.0) to ensure double frictional load for locking function to perform. Thus avoids the rattling noise due to metal to metal contact.

Although, the invention has been described and illustrated with respect to the exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention. ,CLAIMS:WE CLAIM:
1. A ball and ramp locking mechanism of telescopic steering column for vehicles, comprising:
a main bracket (2.1) with one or more square slots;
an upper column assembly (1.0);
a lower column assembly (2.0);
a clamp bracket (1.1) with one or more slots;
a stationary static ramp housing (3.1) with one or more pockets;
a rotatable dynamic ball seat housing (3.2);
a stationary bearing housing (3.5) comprises of a thrust bearing (3.6) and a washer plate (3.7);
a tie rod;
two or more steel balls (3.9); and
a clamp bolt assembly (4.0) comprises of a lever handle (4.1) and a lock nut (4.2),
wherein during actuation, the dynamic ball seat housing (3.2) displaces apart and pulls the head of the clamp bolt away from the main bracket (2.1), to create clamping load on the main bracket (2.1) over the clamp bracket (1.1) to perform clamping function, and the ball and ramp locking mechanism locks the position of the telescopic steering column,
the static ramp housing (3.1) and the dynamic ball seat housing (3.2) with circumferential pockets are milled for ball location and movement, and
the external load acting on the upper column assembly (1.0) is given by a clamp bolt on the clamp bracket (1.1) parallel to the direction of the slit opening, and the slit in the outer column tube compress and collapses over the lower column tube of lower column assembly (2.0) to perform locking function with the double frictional load.

2. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the main bracket (2.1) with the square slot positions the static ramp housing (3.1) and the bearing housing (3.5) both in a same line and rotation of these members are arrested through the square slot.

3. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the clamp bracket (1.1) connects the static ramp housing (3.1) and the bearing housing (3.5) through a clamp bolt passing through the slot for height adjustment preferably between 20 to 100mm.

4. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the static ramp housing (3.1) comprises pockets for the steel ball (3.9) at clamping and unclamping position around a pitch diameter connected through a sliding ramp.

5. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the dynamic ball seat housing (3.2) comprises pockets for the steel ball (3.9) positioned around a pitch diameter equivalent to the static ramp housing (3.1).

6. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the steel balls (3.9) are placed in between the pockets provided on the static ramp housing (3.1) and the dynamic ball seat housing (3.2).

7. The ball and ramp locking mechanism of telescopic steering column for vehicles as claimed in claim 1, wherein the washer plate (3.7) in bearing housing (3.5) on other side of the main bracket (2.1) is tied to the clamp bolt with a lock nut (4.2), squeezed to bolt.

8. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the bearing housing (3.5) is positioned in line with the static ramp housing (3.1) in the main bracket (2.1) providing the space for the thrust bearing (3.6) and the washer plate (3.7).

9. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the clamp bolt assembly (4.0) connects an actuating lever and the dynamic ball seat housing (3.2) through a spline.

10. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the tie rod and the dynamic housing (3.2) is connected through the spline moving the ball over the static ramp housing (3.1), tied through other end with the washer housing with the bearing housing (3.5) and the washer plate (3.7) locked with the lock nut (4.2).

11. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the static ramp housing (3.1) and the dynamic ball seat housing (3.2) protects the locking mechanism.

12. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the main bracket (2.1) base is mounted on a tilt carriage of the vehicle below the dashboard.

13. The ball and ramp locking mechanism of telescopic steering column for vehicles, wherein the clamp bracket (1.1) is welded to the upper column assembly (1.0).