Title of Invention

"IMPROVED TELESCOPIC STEERING COLUMN

Abstract

The present invention provides an improved telescopic steering column comprising.. - column j acket assembly, - steering shaft assembly having a shaft and tube housed in said column jacket assembly characterized in that strips of predetermined shape and size as herein described, consisting of sheet metal as base material are placed between the said shaft and tube of steering shaft assembly to create predetermined resistance between shaft and tube for telescopic movement, the arrangement being such that the driver can move the steering wheel attached to said steering shaft towards or away from him along the column axis by applying a predetermined force on steering wheel.

Full Text

This invention relates to an improved telescopic steering column for automotive applications. BACKGROUND OF THE INVENTION: Telescopic feature in the steering column makes the driver enable to adjust the steering wheel to the desired position while driving and also allowing the driver to position the steering wheel to a position that offers least resistance to him during the entry and exit from the vehicle. Fig 1 shows the conventional steering column with telescopic feature. The working mechanism for conventional steering column is explained in figure-2. Steering column consists of Column jacket assembly (2) and steering shaft assembly (1). The steering shaft assembly (1) is housed inside the column jacket assembly (2). The upper end of steering shaft assembly is connected with steering wheel (SW). The mounting bracket (M) of column jacket assembly is fixed to vehicle body and the steering shaft assembly (1) can be moved by operating the lever (L). When the driver needs to adjust the position of steering wheel, he pushes down the lever (L) and adjusts the steering wheel position by pulling and pushing the steering wheel along the column axis. (A) After setting the steering wheel position, the lever is pulled up to lock it and fix the position. Telescopic arrangement in the conventional steering shaft consists of middle shaft (3) and tube (4) wherein the spring strip (5) is fixed on middle shaft by help of plastic resin (P). The arrangement being such that the plastic resin (P) and spring strip (5) create a predetermined interference between middle shaft (3) and tube (4) and the said middle shaft can slide inside the said tube (4). Sliding load and clearances between tube (4) and middle shaft (3) are controlled by putting spring strip (5) in between them. The main disadvantages of this mechanism are as follows: - - The mechanism is expensive as it contain the plastic resin and complex manufacturing process - Degradation in quality performance because of wear of plastic resin. - High production cycle time The object and summary of the invention The object of the instant invention is to obviate the above disadvantages and to provide the Telescopic steering shaft at low cost, low production cycle time and easy to manufacture. To achieve the said objective this invention provides an improved telescopic steering column comprising.. column j acket assembly, steering shaft assembly having a shaft and tube housed in said column jacket assembly characterized in that strips of predetermined shape and size as herein described , consisting of sheet metal as base material are placed between the said shaft and tube of steering shaft assembly to create predetermined resistance between shaft and tube for telescopic movement, the arrangement being such that the driver can move the steering wheel attached to said steering shaft towards or away from him along the column axis by applying a predetermined force on steering wheel. The shape and size of said strips vary depending upon the sliding load required for telescopic movement. The shape is preferably wave shape to minimize the friction between said shaft and tube without affecting the clearance between them. Brief Description of the drawings: The invention will now be described with reference to the accompanying drawings Fig-1 shows the exploded view of conventional telescopic steering column, column jacket assembly and steering shaft assembly. Fig-2 shows the working of said conventional telescopic steering column Fig-3 shows the conventional telescopic arrangement in the steering shaft assembly Fig-4 shows the exploded and sectional view of telescopic steering shaft according to this invention Detailed Description In fig -1, conventional steering shaft assembly (1), column jacket assembly (2) and column assembly-C is shown. Fig-2 shows the working of said conventional telescopic column. When the driver needs to adjust the position of steering wheel, he pushes down the lever (L) and adjusts the steering wheel (W) position by pulling or pushing the steering wheel along the column axis (A). After setting the steering wheel position, the lever is pulled up to lock it and fix the position of steering wheel (SW). Fig 3 shows the steering shaft (3), tube (4), spring stop (5), plastic resin (P) used to hold said strip (5) and universal joint assembly (U). Fig-4 relates to the instant invention showing the steering shaft (3), tube (4), universal joint (U) and stops (6). The shape and size of stops (6) vary according to the sliding load required for telescopic movement. The shape of the strip (6) is preferably wave shape to minimize the friction between shaft and tube without affecting the clearance between them. EXAMPLE: For instance, to achieve the sliding load of 20 Kgf the dimensions 'L', 'W, 'T' and number of waves of the said stops (6) will be different than the dimensions required to achieve sliding load of 50 Kgf. Advantage of Instant invention: - Low cost as plastic resin is not required - Easy to manufacture as plastic molding process is avoided - Better quality performance as deterioration of plastic will not occur during usage. We Claim: 1. An improved telescopic steering column comprising - column jacket assembly (2), - steering shaft assembly (1) having a shaft (3) and tube (4) housed in said column jacket assembly characterized in that strips (5) of predetermined shape and size such as herein described, consisting of sheet metal as base material are placed between the said shaft (3) and tube (4) of steering shaft assembly (1) to create predetermined resistance between shaft (3) and tube (4) for telescopic movement, the arrangement being such that the driver moves the steering wheel attached to said steering shaft towards or away from him along the column axis by applying force on steering wheel. 2. An improved telescopic steering column as claimed in claim 1, wherein the shape is preferably wave shape to minimize the friction between said shaft (3) and tube (4) without affecting the clearance between them.

Documents:

661-DEL-2005-Abstract-(01-03-2012).pdf

661-del-2005-Abstract-(26-04-2011).pdf

661-del-2005-abstract.pdf

661-DEL-2005-Claims-(01-03-2012).pdf

661-del-2005-Claims-(26-04-2011).pdf

661-del-2005-claims.pdf

661-DEL-2005-Correspondence Others-(01-03-2012).pdf

661-del-2005-Correspondence-Others-(26-04-2011).pdf

661-del-2005-correspondence-others.pdf

661-DEL-2005-Description (Complete)-(01-03-2012).pdf

661-del-2005-description (complete).pdf

661-del-2005-description (provisional).pdf

661-del-2005-drawings.pdf

661-DEL-2005-Form-1-(01-03-2012).pdf

661-del-2005-Form-1-(26-04-2011).pdf

661-del-2005-form-1.pdf

661-del-2005-form-18.pdf

661-DEL-2005-Form-2-(01-03-2012).pdf

661-del-2005-form-2.pdf

661-del-2005-form-3.pdf

661-del-2005-form-5.pdf

661-DEL-2005-GPA-(01-03-2012).pdf

661-del-2005-GPA-(26-04-2011).pdf

661-del-2005-gpa.pdf