Abstract:
The present invention relates to a telescopic device of a steering column for a vehicle, wherein plural locking blocks are installed so as to provide fixing force of an telescopic outer member and an telescopic inner member at several positions, and the locking blocks are connected by a connection rod so that they have equal fixing force relative to the pivot of an operating lever, thereby achieving stability and quietness of a product in addition to reliability of the product.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a telescopic device of a steering column for a vehicle, more particularly to a telescopic device of a steering column for a vehicle, in which a plurality of locking blocks are installed for providing fixing force between a telescopic outer member and a telescopic inner member, wherein the fixing force of each locking block can be equally distributed.  
           [0003]    2. Description of the Related Art  
           [0004]    Generally, the telescopic device is used for adjusting the length of a steering wheel according to the body type of a driver.  
           [0005]    Referring to FIGS. 1 and 2, a typical telescopic device  100  includes a locking block  104  contacting with a telescopic inner member  112 , and a tapered block  106  coupled with an operating lever  108  stacked within a block case  102  formed at the bottom side of a telescopic outer member  110 .  
           [0006]    When the tapered block  106  is moved along an inclined bottom surface of the block case  102  according to the pivot of the operating lever  108 , the locking block  104  is moved vertically to selectively provide fixing force to the telescopic inner member  112  so as to make the telescopic inner member  112  closely contact and become fixed on the telescopic outer member  110  or to slide on the telescopic outer member, thereby adjusting the length of a steering shaft  114  coupled with a steering wheel (not shown) on a tip end.  
           [0007]    The telescopic device  100  as stated above, however, is installed at a specific upper position of the steering shaft  114  adjacent to the steering wheel so as to enable a driver to easily manipulate the telescopic device, so the fixing force provided by the telescopic device  100  is hardly transmitted to the lower part of the steering shaft  114 , which results in a reduction of the coupling force between the lower parts of the telescopic inner member  112  and the telescopic outer member,  110  as well as the generation of noise by the vibration due to an expanded gap.  
           [0008]    In addition, the gap between the telescopic inner member  112  and the telescopic outer member  110  is adjusted to be reduce so as to complement the limited fixing force, but even so it results in a rise in the cost of production and the number of defective products due to the precise process of forming the mating diameter surfaces of the telescopic inner member  112  and the telescopic outer member  110 , and the reliability of the product deteriorates due to the poor operation depending on the reduction of the gap.  
         SUMMARY OF THE INVENTION  
         [0009]    It is, therefore, an object of the present invention to provide a telescopic device of a steering column for a vehicle, wherein a plurality of locking blocks are installed so as to provide fixing force of an telescopic outer member and an telescopic inner member at several positions, and the locking blocks are connected by a connection rod so that they have equal fixing force relative to the pivot of an operating lever, thereby achieving stability and quietness of a product, in addition to reliability of the product.  
           [0010]    To achieve the above object, there is provided a telescopic device of a steering column for a vehicle, in which a telescopic inner member is slid or fixed on a telescopic outer member by selectively pivoting a telescopic lever, including a plurality of locking blocks received in a plurality of block cases formed on the telescopic outer member, for selectively providing a fixing force to the telescopic inner member, as moving along a inclined bottom surfaces of the block cases; and a fastening member having one end pivotally attached to one end of a connection rod for inter-connecting the locking blocks to contact with the locking block on an outer circumferential surface, and the other end of the fastening member is attached to one end of the telescopic lever.  
           [0011]    The fastening member has a cam shape capable of varying a space between the locking blocks by moving the locking blocks in opposite directions according to a variation of contacting region between the curved outer circumferential surface of the fastening member and the locking block while the fastening member is pivoted synchronously with the pivot of the telescopic lever.  
           [0012]    The telescopic device further includes an elastic member inserted between the block case and the locking block so as to enable the displacement of the locking block to be rapidly performed according to the pivot of the telescopic lever.  
           [0013]    The locking block is a hexahedron or a circular shape in order to be able to provide the fixing force to the telescopic inner member, while being moved along the inclined bottom surface of the block case.  
           [0014]    According to another aspect of the present invention, a telescopic device of a steering column for a vehicle is provided that includes a telescopic inner member slidably mounted on a telescopic outer member and selectively fixable thereto by pivoting a telescopic lever. The telescopic device includes a plurality of block cases formed on the telescopic outer member, with the block cases including inclined bottom surfaces, a plurality of locking blocks, each locking block received in a respective one of the block cases, and an actuating mechanism configured to interconnect the locking blocks such that the locking blocks are simultaneously movable toward and away from each other to selectively engage and disengage an outer circumferential surface of the telescopic inner member so that the telescopic inner member and the telescopic outer member are selectively locked and unlocked relative to one another.  
           [0015]    In a further aspect of the present invention, the actuating mechanism of the telescopic device may include a connection rod that inter-connects the locking blocks, and a fastening member having a portion pivotally attached to one end of the connection rod and another portion is fixed to the telescopic lever, whereby operation of the telescopic lever causes the fastening member to move the locking blocks toward and away from one another to cause the locking blocks selectively engage and disengage from an outer circumferential surface of the telescopic inner member. Furthermore, the locking blocks are moveable along the inclined bottom surfaces of the block cases to cause the locking blocks to selectively engage and disengage the outer circumferential surface of the telescopic inner member.  
           [0016]    In still further aspects of the present invention, the telescopic device the fastening member of the telescopic device may have a cam shape capable of varying a space between the locking blocks by moving the locking blocks in opposite directions according to a variation of contacting region between the curved outer circumferential surface of the fastening member and one of the locking blocks while the fastening member pivots synchronously with the pivot of the telescopic lever. Additionally, an elastic member may be inserted between at least one block case and a respective locking block so as to enable the displacement of the locking block to be rapidly performed according to the operation of the telescopic lever. Moreover, the locking blocks may have one of a hexahedron shape and a circular shape in order to be able to provide the fixing force to the telescopic inner member, while being moved along the inclined bottom surfaces of the block case. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    The above objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:  
         [0018]    [0018]FIG. 1 is a side view illustrating a typical telescopic device;  
         [0019]    [0019]FIG. 2 is a cross sectional view taken on the line II-II in FIG. 1;  
         [0020]    [0020]FIG. 3 is a diagrammatic perspective view illustrating a telescopic device according to a preferred embodiment of the present invention; and  
         [0021]    [0021]FIG. 4 is a cross sectional view taken on the line IV-IV in FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    A telescopic device of a steering column for a vehicle according to an embodiment of the present invention will now be described with reference to the accompanying drawings.  
         [0023]    [0023]FIG. 3 is a diagrammatic perspective view illustrating the telescopic device according to an embodiment of the present invention, and FIG. 4 is a cross sectional view taken on the line IV-IV in FIG. 3.  
         [0024]    As shown in FIGS. 3 and 4, the telescopic device  10  according to the present invention includes a plurality of locking blocks  14  received in block cases  12  formed on a telescopic outer member  20 , a connection rod  16  for inter-connecting the locking blocks  14  each other so as to regulate the movement of the locking blocks  14 , and a fastening member  19  having one end attached to one end of a telescopic lever  18  and the other end is attached to one end of the connection rod  16  to contact with one of the locking blocks  14  so as to enable the locking blocks  14  to be reciprocated along an inclined bottom surface of the block cases by the pivot of the telescopic lever  18 .  
         [0025]    The telescopic outer member  20  is provided with the block cases  12  facing each other with an appropriate space therebetween, and the block cases  12  are provided with the inclined bottom surfaces descending away from each other. The locking blocks  14  are received in the block cases  12  so that they can push the outer circumferential surface of a telescopic inner member  22  upwardly while reciprocating along the inclined bottom surfaces in opposite directions so as to make the telescopic inner member  22  closely contact the telescopic outer member  20  member.  
         [0026]    The connection rod  16 , which is attached to the locking blocks  14  so as to penetrate them, also serves to secure the position of the locking blocks  14  within the block case  12 . The one end of the connection rod  16  is pivotally attached to the fastening member  19  as described above, and additionally the other end of the connection rod  16  is attached to an adjustable stop member  16   a , for example, a nut threaded on the end of the connection rod  16 . The locking blocks  14  are positioned between the stop member  16   a  and the fastening member  19  to contact them so as to regulate the moving distance of the locking blocks  14 .  
         [0027]    The fastening member  19  has a cam shape having a long axis and a short axis, and a part of the outer circumferential surface thereof is in contact with one of the locking blocks  14  so as to be fastened to the one end of the connection rod  16 . Thereby, since a contacting region between the fastening member  19  and the locking block  14  is changed according to the curved portions of the long axis and the short axis while the fastening member  19  is pivoted, the space between the locking blocks  14  can be adjusted. In addition, the pivot of the fastening member  19  depends on the telescopic lever  18  attached to the one end thereof.  
         [0028]    In addition, the telescopic device  10  includes an elastic member  30  to be positioned between the inner walls of the locking block  14  and the block case  12  so that it can rapidly respond to the space variation between the locking blocks  14  according to the pivot of the fastening member  19 .  
         [0029]    The elastic member  30  is preferably a disc spring, or a coiled spring, or the like.  
         [0030]    In addition, the telescopic device  10  is used for selectively providing a fixing force to the telescopic inner member  22  while the locking blocks  14  move along the inclined bottom surfaces of the block cases  12 . The shape of the locking block  14  received in the block case  12  can be selected into various shapes including a circular shape, a dihedron, a trihedron, a tetrahedron, a pentahedron, a hexahedron, and so on except its upper surface having a same curvature as the telescopic inner member  22 .  
         [0031]    The operation of the telescopic device according to the present invention constituted as stated above will be described below.  
         [0032]    When the telescopic lever  18  is rotated, the fastening member  19  is rotated about the one end of the connection rod  16 , and then the locking blocks  14 , contacting with the fastening member  19  variably in correspondence to the length variation of the long axis/the short axis, are reciprocated along the inclined bottom surfaces of the block cases  12  in opposite directions so as to selectively provide the desired fixing force to the telescopic inner member  22  upwardly, thereby the telescopic inner member  22  can closely contact the telescopic outer member  20  or can be drawn/inserted from/to the telescopic outer member  20  in order to be able to readily adjust the length of a steering shaft  24  according to the convenience of a driver.  
         [0033]    The effect of the present invention configured as stated above will now be described.  
         [0034]    Since the locking blocks received in the block cases formed on the telescopic outer member provide the fixing force to the telescopic inner member at positions so as to stably secure the telescopic inner member to the telescopic outer member, it is therefore possible to completely eliminate noise caused by the vibration due to the unstable fixing structure of the typical telescopic device, to eliminate the necessity of accurate processing, and to prevent the poor operation, thus improving the reliability of a product.  
         [0035]    While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.  
         [0036]    Although the invention has been described with reference to an exemplary embodiment, it is understood that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein. Instead, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.  
         [0037]    The present application claims priority under 35 U.S.C. § 119 of Korean (Republic of Korea) Patent Application No. KR 2001-35877, filed on Nov. 21, 2001, and Korean (Republic of Korea) Patent Application No. KR 2002-517, filed on Jan. 4, 2002, and the disclosures of which are expressly incorporated by reference herein in their entireties.