Abstract:
A steering apparatus ( 1 ) for vehicles capable of undergoing at least telescopic movement is proposed which enables substantial weight and cost reduction through shortening of the overlap (L′) of a movable jacket ( 7 ) with a base jacket ( 6 ) without affecting the high support rigidity of the movable jacket; also ricketiness of the movable jacket is removed; the movable jacket is engaged with the base jacket in a manner such that the movable jacket can freely slide, and a first lock assembly ( 20 ) locks the telescopic movement in synchronism with a second lock assembly ( 40 ) when an operation lever ( 27 ) is shifted and these lock assemblies unlock the telescopic movement in synchronism too.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to steering apparatus for vehicles equipped with a lock mechanism for locking at least the telescopic movement.  
         [0003]     2. Description of the Related Art  
         [0004]     Among the steering apparatuses for changing the vehicle direction, there are some with which it is possible to adjust the up-and-down tilt angle and/or to telescopically change the length of the steering wheel shaft so as to enable the driver to take a posture most suitable to his or her physique.  
         [0005]      FIG. 8  shows an example of such tilt/telescopic type vehicle steering apparatus, which is capable of tilt movement and telescopic movement (ref. patent related document 1).  
         [0006]      FIG. 8  is a half cross-sectional side view of a conventional steering apparatus  101  for vehicles, wherein reference numeral  102  designates a steering shaft passed inside a cylindrical steering column  105 , and this steering shaft  102  comprises an upper shaft  103  and a lower shaft  104 , which are spline-fitted such that they are freely slidable in the axial directions. Incidentally, a steering wheel, not shown, is fixed at the upper end of the upper shaft  3 .  
         [0007]     Also, the steering column  105  has its movable jacket  107  inserted in a base jacket  106 , which is attached to the vehicle body, in a manner such that the movable jacket  107  is capable of sliding in the directions along the column axis, and the upper shaft  103  of the steering shaft  102  is held in the movable jacket  107  in a manner such that the upper shaft  103  is freely rotatable about its axis by virtue of a bearing  109 , and the lower shaft  104  of the steering shaft  102  is held in the base jacket  106  in a manner such that the lower shaft  104  is freely rotatable about its axis by virtue of a bearing  110 .  
         [0008]     The base jacket  106  is pivotally connected to brackets  113  and  115  via a bolt  114  in a manner such that the base jacket  106  is capable of swinging up and down, and the upper end portion of the bracket  113  is formed integrally with a pair of left and right parallel side plate portions  113   a,  which extend downwards. This pair of side plate portions  113   a  of the bracket  113  cooperatively sandwich between them a clamp member  124 , which is fixed to the movable jacket  107 , from outside, and each side plate portion  113   a  is formed with a tilt adjustment slot  123 , which is elongated in upward and downward directions.  
         [0009]     A tilt bolt  126  is passed through the tilt adjustment slots  123  bored through the side plate portions  113   a  of the bracket  113  and circular holes, not shown, bored through the clamp member  124 , and one end of an operation lever  127  locked to the tilt bolt  126 . Incidentally, although it is not shown in  FIG. 1 , a cam lock assembly is installed on the tilt bolt  126  between the operation lever  127  and the bracket  113 .  
         [0010]     Thus, the bracket  113 , the clamp member  124 , the tilt bolt  126 , the operation lever  127 , the cam lock assembly, and others, not shown, constitute a tilt/telescopic lock means, and when the operation lever  127  is turned to increase the distance between the side plate portions  113   a  of the bracket  113  by virtue of the cam lock assembly, the bracket  113  ceases to clamp the clamp member  124  and the clamp member  124  ceases to clamp the movable jacket  107  whereby the lock means is unlocked and it becomes possible to effect the telescopic movement of the steering wheel by shifting the movable jacket  107  together with the upper shaft  103  of the steering shaft  102  in the axial directions, and also it becomes possible to effect the tilt movement of the steering wheel by swinging up and down the steering column  105  and the steering shaft  102  about the bolt  114 , this swinging being limited to an extent corresponding to the limited range of the movement of the tilt bolt  126  within the tilt adjustment slot  123  of the bracket  113 .  
         [0011]     Then, after the desired telescopic movement and the tilt movement for adjustment are completed, as described above, the operation lever  127  is turned back, whereupon the cam lock assembly works to decrease the distance between the side plate portions  113   a  of the bracket  113  with the result that the bracket  113  clamps the clamp member  124  and the clamp member  124  clamps the movable jacket  107 ; thus, the lock means is in locking operation and consequently the steering shaft  102  is prevented from making any further telescopic movement as well as tilt movement, and thus the steering wheel stays at the up-and-down tilt angle and the axial position as of the adjustment.  
         [0012]     Admitted prior art: Japanese pre-Patent Publication 2001-347953  
         [0013]     However, in the above-described conventional steering apparatus  101  for vehicles, the length L′, which is the overlap length by which the movable jacket  107  extends in the base jacket  106 , had always to be substantially great in order to secure a high support rigidity of the movable jacket  107  of the steering column  105 ; as a result, the lengths of the base jacket  106  and the movable jacket  107  tended to be undesirably great and this prevented weight and cost reduction of the steering apparatus  101 .  
         [0014]     Also, in order to prevent ricketiness at the overlapping between the base jacket  106  and the movable jacket  107 , it was necessary to permanently press the movable jacket  107  upon one side part of the inner wall of the base jacket  106 , so that at the time of telescopic movement the sliding friction of the movable jacket  107  got so great that it taxed driver&#39;s arms.  
       SUMMARY OF THE INVENTION  
       [0015]     The present invention was made in view of the afore-mentioned problems, and it is an object of the invention to propose a steering apparatus for vehicles, which enables substantial weight and cost reduction through shortening of the overlap between the movable jacket and the base jacket without affecting the high support rigidity of the movable jacket of the steering column, and also the proposed steering apparatus does not experience ricketiness at the overlap between the two jackets while the sliding friction of the movable jacket at the time of the telescopic movement is reduced.  
         [0016]     In order to attain the above-described object, the invention as claimed in Claim  1  is characterized by that a steering apparatus for vehicles capable of undergoing at least telescopic movement comprises a steering column, a base jacket attached to the vehicle body, a movable jacket engaged with the base jacket in a manner such that the movable jacket can freely slide in directions of the axis of the steering column, a first lock assembly, a second lock assembly, an operation lever, and a link for interconnecting the first lock assembly to the second lock assembly in a manner such that these assemblies lock the telescopic movement in synchronism by preventing the movable jacket from sliding when the operation lever is shifted in a predetermined direction.  
         [0017]     The invention as claimed in Claim  2  is characterized by that, further to the invention as claimed in Claim  1 , the steering apparatus for vehicles further comprises a cam lock subassembly in the first lock assembly, an adjust bracket fixed to the vehicle body, a distance bracket fixed to the movable jacket, and a first bolt inserted through both of these brackets and disposed to turn together with the operation lever, wherein the first lock assembly is constructed in a manner such that the adjust bracket embraces the distance bracket and such that a turning by the operation lever of the first bolt drives the cam lock subassembly whereby the adjust bracket either strengthens or loosens its embrace of the distance bracket to selectively effect locking and unlocking of the telescopic movement at the first lock assembly.  
         [0018]     The invention as claimed in Claim  3  is characterized by that, further to the invention as claimed in Claim  1 , the steering apparatus for vehicles further comprises a fixture means ( 41 ,  42 ) fixed to the stationary bracket, a second bolt threadably engaged with this fixture means and disposed to be turned in synchronism with the first bolt, and a flexible collar provided between the stationary bracket and the movable bracket, wherein the second lock assembly is provided at a junction where the base jacket and the movable jacket are engaged with each other, and a turning of the second bolt causes the second bolt to proceed or recede in the direction orthogonal to the steering column axis to start or stop deforming the flexible collar whereupon locking and unlocking of the telescopic movement at the second lock assembly is selectively effected.  
         [0019]     The invention as claimed in Claim  4  is characterized by that, further to the invention as claimed in Claim  3 , the flexible collar has a plurality of thick parts, which have thicknesses greater than the other parts and are separated from each other in circumferential direction.  
         [0020]     The invention as claimed in Claim  5  is characterized by that, further to the invention as claimed in and one of Claims  1  through, the base jacket is adapted to swing upward and downward about its lower end portion where it is pivotally attached to the vehicle body, and the first lock assembly is adapted to lock the tilt movement simultaneously as it locks the telescopic movement and also to unlock the tilt movement simultaneously as it unlocks the telescopic movement.  
         [0021]     According to the inventions of Claims  1  to  3 , a first lock assembly is interconnected to a second lock assembly via a link such that it is possible to cause both of these lock assemblies to lock/unlock the telescopic movement through single shifting of the operation lever, thus operation becomes simpler. Also, since two lock assemblies are provided as the lock means for locking at least the telescopic movement, the movable jacket is supported by these two lock assemblies, and thus the support rigidness is increased, whereby the distance by which the movable jacket is inserted in the base jacket can be much reduced from that in a conventional steering apparatus, and thus it is possible to reduce the weight and the manufacturing cost of the steering apparatus. Furthermore, as one of the lock assemblies is provided at the junction where the base jacket engages with the movable jacket, it is possible to support the movable jacket with this lock assembly so that the ricketiness is prevented at this junction, and during the telescopic movement, since this lock assembly is unlocked, the sliding friction on the movable jacket is minimized so that easy telescopic movement is possible.  
         [0022]     According to the invention of Claim  4 , since the flexible collar provided between the stationary bracket and the movable bracket has a plurality of parts thicker than the other parts and separated from each other in circumferential direction, the resin collar presses upon the movable jacket especially strongly at these thicker parts so that sliding movement of the movable jacket is effectively forbidden and a reliable lock is established, and also the movable jacket is caused to firmly press on the base jacket whereby any rickety movement between these jackets is nullified.  
         [0023]     According to the invention of Claim  5 , in the case of a tilt/telescopic type vehicle steering apparatus, which is capable of tilt movement and telescopic movement, it is now possible to simultaneously lock or unlock the telescopic movement and the tilt movement by one-touch shifting of the operation lever. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]     The features and advantages of the present invention will become more clearly appreciated from the following description taken in conjunction with the accompanying drawings in which:  
         [0025]      FIG. 1  is a partially cross-sectional side view of a steering apparatus for vehicles according to the present invention;  
         [0026]      FIG. 2  is an enlarged cross-sectional view taken along the line A-A of  FIG. 1 ;  
         [0027]      FIG. 3  is an enlarged cross-sectional view taken along the line B-B of  FIG. 1 ;  
         [0028]      FIG. 4  is a view as seen in the direction of the arrow C of  FIG. 3 ;  
         [0029]      FIG. 5  is an enlarged cross-sectional view taken along the line D-D of  FIG. 1 ;  
         [0030]      FIG. 6  is a half cross-sectional side view of a resin collar;  
         [0031]      FIG. 7  is a cross-sectional view taken along the line E-E of  FIG. 6 ; and  
         [0032]      FIG. 8  is a half cross-sectional side view of a conventional steering apparatus for vehicles. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]     Some embodiments of the present invention will be explained here with reference to the attached drawings.  
         [0034]     In a steering apparatus  1  for vehicles shown in  FIG. 1 , a reference numeral  2  designates a steering shaft inserted in a cylindrical steering column  5 , and this steering shaft  2  is constituted by an upper shaft  3  and a lower shaft  4 , which are spline-fitted in the steering column  5  such that they are freely slidable in the axial directions. Incidentally, a steering wheel, not shown, is fixed at an upper end of the upper shaft  3 , and a lower end of the lower shaft  4  is connected to a steering gear box, not shown either, via an adjustable joint, nor shown.  
         [0035]     Also, the steering column  5  has its movable jacket  7  inserted in a base jacket  6 , which is attached to the vehicle body, in a manner such that the movable jacket  7  is capable of sliding on a resin collar  8 , shown in  FIG. 5 , in the directions along the column axis, and the upper shaft  3  of the steering shaft  2  is held in the movable jacket  7  in a manner such that the upper shaft  3  is freely rotatable about its axis by virtue of a bearing  9 , and the lower shaft  4  of the steering shaft  2  is held in the base jacket  6  in a manner such that the lower shaft  4  is freely rotatable about its axis by virtue of a bearing  10 .  
         [0036]     Now, a channeled bracket  11 , which has a channel on one side, is welded to an outer circumference surface of a lower part of the base jacket  6 , as shown in  FIG. 1  and  FIG. 2 , and a pair of parallel side plates  11   a,    11   a  of the bracket  11  are firmly caught in a bracket  12  having a cross section of a letter “U”, with the open side facing downward, as seen in  FIG. 2 , and this bracket  12  is attached to a vehicle-side bracket  13 , which is connected to the vehicle body. Next, the bracket  12  is connected to a pair of tilt hinges  14 , in a manner such that each tilt hinge  14  penetrates the corresponding side plate  12   a  of the bracket  12  and the corresponding side plate  11   a  of the bracket  11  and such that the bracket  12  is capable of freely turning about the tilt hinges  14 ; hence, the movable jacket  7  (or the steering column  5  and the steering shaft  2 ) is held in the vehicle in a manner such that it can swing upward and downward about its rear end portion where the tilt hinges  14  penetrate it.  
         [0037]     In this particular embodiment, a first lock assembly  20  and a second lock assembly  40 , as lock means for the tilt/telescopic movement, are provided at two locations along the axis of the steering column  5 , and, as will be described later, the first lock assembly  20  is disposed to lock and unlock the tilt and telescopic movements and the second lock assembly  40  is disposed to lock and unlock the telescopic movement.  
         [0038]     Now, the construction of the first lock assembly  20  will be explained with reference to  FIGS. 1, 3 , and  4 .  
         [0039]     At an upper end portion of the vehicle-side bracket  13  is fixed a U letter-shaped adjust bracket  21  with a pair of bolts  22 ,  22  in such a manner that the letter U opens downwards; through each of a pair of parallel side plate portions  21   a,    21   a  of this adjust bracket  21  is formed a vertically elongated tilt adjustment slot  23 . Incidentally, the bolts  22  are inserted through slots  13   a,  respectively, which are formed in the vehicle-side bracket  13  and are elongated in the direction of the vehicle length (that is, the fore-and-aft direction of the vehicle), and this collapsible or deformable construction allows movement of the adjust bracket  21  toward the vehicle front at the time of secondary shock thereby effecting absorption and softening of the shock.  
         [0040]     Also, on the circumferential surface of the movable jacket  7  of the steering column  5  is welded a U letter-shaped distance bracket  24  in a manner such that the letter U opens downward, and through each of a pair of parallel side plates  24   a,    24   a  of this bracket  24  is formed a telescopic slot  25 , which is elongated in the direction of the vehicle length (or in the direction of the column axis line, ref.  FIG. 4 ).  
         [0041]     Thus, the adjust bracket  21  fits on the distance bracket  24  from outside as each one of the side plate portions  24   a  of the distance bracket  24  is closely touched by the respective side plate portions  21   a  of the adjust bracket  21 , and a tilt bolt  26  is passed through the tilt adjustment slot  23  formed through the adjust bracket  21  and the telescopic slot  25  formed through the distance bracket  24 . Therefore, the movable jacket  7  is installed in a manner such that it can move in the direction of the vehicle length (or in the direction of the column axis line) together with the upper shaft  3  through a distance equal to the distance through which the tilt bolt  26  can move in the telescopic slot  25 , whereby a telescopic motion (or tilt adjustment) of the steering wheel, not shown, is enabled.  
         [0042]     Incidentally, as shown in  FIG. 3 , an operation lever  27  and a cam lock subassembly  28  are engaged between a head portion of the tilt bolt  26  and one of the side plate portions  21   a  of the adjust bracket  21 , and the operation lever  27  has one of its ends penetrated by the tilt bolt  26 . Now, the head portion of the tilt bolt  26  is engaged with a plate stopper  29 , and, as shown in  FIG. 1 , when a bolt  31  inserted through an arc-shaped slot  30  formed through the stopper  29  is screwed to threadably engage with the operation lever  27 , the operation lever  27  becomes fixed to the tilt bolt  26  such that these two turn together as one body, and also it becomes possible to restrict the position of the operation lever  27  to such limits corresponding to the range of movement of the bolt  31  within the slot  30  of the stopper  29 .  
         [0043]     Now, the cam lock subassembly  28  is composed of, as shown in  FIG. 3 , a movable cam lock member  28   a  disposed to turn together with the tilt bolt  26  and a stationary cam member  28   b  engaged with the tilt adjustment slot  23  bored through the adjust bracket  21 , and the movable cam lock member  28   a  and the stationary cam member  28   b  are engaged with each other via their concavo-convex cams formed on the respective faces facing each other.  
         [0044]     On the other hand, a locking block  32  is provided on the other end (tail end) portion of the tilt bolt  26 , which extends past the other side plate portion  21   a  of the adjust bracket  21 , in a manner such that the locking block  32  is capable of sliding on the tilt bolt  26 , and this locking block  32  is stopped by a nut  35  via a thrust bearing  33  and a washer  34  from moving off the tilt bolt  26  and at the same time the block  32  is permanently urged toward the tail end of the tilt bolt by a spring  36 .  
         [0045]     Also, at the other side of the tilt adjustment slot  23  of the side plate portion  21   a  of the adjust bracket  21  are formed two rows of tilt lock cogs  37  (ref.  FIG. 4 ), and these tilt lock cogs  37  are selectively engaged with lock cogs formed on the locking block  32 .  
         [0046]     Hence, the steering column  5  and the steering shaft  2  inserted therein are capable of swinging up and down about the tilt hinges  14  (ref.  FIG. 1  and  FIG. 2 ) to an extent corresponding to the limited range of movement of the tilt bolt  26  (or more precisely the stationary cam member  28   b  of the cam lock subassembly  28 ) within the tilt adjustment slot  23 , and by virtue of these swinging movements the upward and downward tilting position of the steering wheel, not shown, is adjustable.  
         [0047]     Next, the construction of the second lock assembly  40  will be explained with reference to  FIG. 1  and  FIG. 5 .  
         [0048]     As is shown in  FIG. 5 , through a side portion of the base jacket  6  is bored a circular hole  6   a,  and a bracket  41  is welded onto the outer circumferential surface of the base jacket  6  to surround the circular hole  6   a.  And a circular hole  41   a  is bored through this bracket  41 , and a nut  42  is welded to the bracket  41  coaxially with this hole  41   a.    
         [0049]     Thus, a telescopic bolt  43  is threadably engaged with the nut  42 , and the fore end of the telescopic bolt  43  is passed through the circular hole  41   a  bored through the bracket  41  and is abuttable against a part of the resin collar  8 .  
         [0050]     Here, the resin collar  8 , as shown in  FIG. 6  and  FIG. 7 , is monoblock-casted of a flexible resin in a shape of cut-away ring, and its outer circumference has two small columnar protrusions  8   a,    8   a  and one large columnar protrusion  8   b,  and as these protrusions  8   a  and  8   b  engage with the circular bores  6   b,    6   a  of the base jacket  6 , respectively, the resin collar  8  is firmly held to the base jacket  6 . Then, a circular hole  8   b - 1  is formed centrally in the protrusion  8   b,  and this circular hole  8   b - 1  receives and engages with the fore end of the telescopic bolt  43 .  
         [0051]     Also, as shown in  FIG. 7 , the resin collar  8  has thick parts  8   c,    8   c,    8   c,  which have thicknesses greater than the other parts, at three circumferentially equidistant positions of the collar (in this embodiment at the positions where protrusions  8   a,    8   a  and  8   b  are formed).  
         [0052]     On the other hand, as shown in  FIG. 1  and  FIG. 5 , one end of a sub-lever  44  is connected to the telescopic bolt  43  via a nut  45 , and the other end of the sub-lever  44  and a middle part of the operation lever  27  are interconnected to each other via a link  46 .  
         [0053]     Next will be explained the telescopic movement of the vehicle steering apparatus  1  of the present invention, and also will be explained its lock/unlock mechanism.  
         [0054]     When the operation lever  27  is in the lock position as depicted in solid line in  FIG. 1 , the first lock assembly  20  and the second lock assembly  40  are disposed to take respective lock positions.  
         [0055]     In other words, since in the first lock assembly  20 , the movable cam member  28   a  of the cam lock subassembly  28  and the cam of the stationary cam member  28   a  engage with each other by their respective convex portions, the tilt bolt  26  is displaced in an axial direction (leftward as viewed in  FIG. 3 ), and as a result, the side plate portions  21   a,  which are monolithic parts of the adjust bracket  21 , are squeezed to decrease the distance between themselves, whereupon they compress the side plate portions  24   a  of the distance bracket  24  inwardly to thereby clasp them firmly. Consequently, a high friction is created between the side plate portions  21   a  of the adjust bracket  21  on one hand and the side plate portions  24   a  of the distance bracket  24  on the other, and this friction prevents the movable jacket  7  and the upper shaft  3  from sliding in the directions of the column axis.  
         [0056]     Also, as described above, when the tilt bolt  26  is axially displaced, the locking block  32  is urged against the tilt lock cogs  37  formed on the adjust bracket  21 , so that the lock cogs of the locking block  32  fall in engagement with the tilt lock cogs  37 , whereby the swing movement of the steering column  5  and the steering shaft  2  about the tilt hinges  14  is prevented and thus the tilt movement of the steering wheel is forbidden.  
         [0057]     Incidentally, in this embodiment, lock cogs are employed as the tilt lock means, but it is also possible to employ lock cogs for telescopic movement and to lock the telescopic system too by causing these lock cogs to go past the tilt adjustment slot  23  of the adjust bracket  21  to engage with lock cogs which are provided along the border of the telescopic slot  25  of the distance bracket  24 . Furthermore, it is also possible to omit the tilt lock cogs, and to lock the tilt mechanism by employing the friction between the adjust bracket  21  and the distance bracket  24 .  
         [0058]     Now, turning to the second lock assembly  40 , when the operation lever  27  is taking the position drawn in solid line in  FIG. 1 , the sub-lever  44  interconnected to the operation lever  27  also takes the position drawn in the solid line in  FIG. 1 , and at this time since the telescopic bolt  43  presses upon the resin collar  8  at its fore end, the resin collar  8  clasps upon the outer circumference of the movable jacket  7  so firmly that the movable jacket  7  is prevented from shifting in the directions of the column axis. Incidentally, as described above, since the resin collar  8  has three thick parts  8   c  formed equidistantly along the circumference, the resin collar  8  presses upon the movable jacket  7  especially strongly at these thick parts  8   c  so that sliding movement of the movable jacket  7  is effectively forbidden and a reliable lock is established, and also the movable jacket  7  is caused to firmly press on the base jacket  6  whereby any rickety movement between the jackets  6  and  7  is nullified.  
         [0059]     Braked both at the first lock assembly  20  and the second lock assembly  40 , the movable jacket  7  and the upper shaft  3  are prevented from sliding in the directions of column axis, and thus the telescopic movement of the steering wheel is locked.  
         [0060]     Next, when it is desired to obtain up-and-down swinging (tilting) movement and expansion-and-contraction (telescopic) movement of the steering wheel for adjustment thereof, the operation lever  27  taking the position drawn in the solid line in  FIG. 1  is turned clock-wise through an angle θ to take the position drawn in two-dot chain line, whereupon the sub-lever  44 , which is interconnected to the operation lever  27  via the link  46 , is caused to turn from the position of solid line to the position of two-dot line; as a result both the first lock assembly  20  and the second lock assembly  40  are brought into their unlock postures.  
         [0061]     In other words, at the first lock assembly  20 , the tilt bolt  26  and the movable cam member  28   a  of the cam lock subassembly  28  are simultaneously turned in one body with the operation lever  27 , whereupon engagement between the movable cam member  28   a  and the stationary cam member  28   b  turns from convex-convex to concave-convex; as a result, the tilt bolt  26  is displaced rightward as viewed in  FIG. 3 . Then, the adjust bracket  21  ceases to clasp the distance bracket  24 , whereupon the movable jacket  7  and the upper shaft  3  are allowed to shift in the directions of the column axis. Also, at the same time, since the locking block  32 , constantly biased by the spring  36 , moves on the tilt bolt  26  in the rightward direction, as viewed in  FIG. 3 , the lock cogs formed on the locking block  32  leave from the tilt lock cogs  37  of the adjust bracket  21  to disrupt the cog engagement. As a result, the tilt lock is unlocked, and the steering column  5  and the steering shaft  2  are allowed to turn about the tilt hinges  14 , so that it is possible to control the up-and-down movement (tilting) of the steering wheel.  
         [0062]     On the other hand, at the second lock assembly  40 , as the sub-lever  44  turns, the telescopic bolt  43  is caused to simultaneously turn in the same direction, and as the telescopic bolt  43  threadably engaged with the nut  42  recedes leftward, as viewed in  FIG. 5 , the pressure imposed on the resin collar  8  by the telescopic bolt  43  is removed, and thus the movable jacket  7  and the upper shaft  3  sheathed therein are allowed to move in the directions of the column axis.  
         [0063]     Now, as described above, the movements of the movable jacket  7  and the upper shaft  3  in the directions of the column axis are not thwarted at the first lock assembly  20  and the second lock assembly  40 , and thus the steering wheel is unlocked and can undergo telescopic movements, whereby it becomes possible to obtain the expansion-and-contraction (telescopic) movement of the steering wheel in the directions of the column axis for lengthwise adjustment.  
         [0064]     When the steering wheel is adjusted by tilting it upward or downward and by expanding or contracting it telescopically in the directions of the steering shaft axis while the first lock assembly  20  and the second lock assembly  40  are in their unlock postures, the driver turns the operation lever  27  from the position drawn in two-dot chain line ( FIG. 1 ) to that drawn in solid line, whereupon the first lock assembly  20  and the second lock assembly  40  again assume their lock postures and the steering wheel is locked from tilting upward or downward and from expanding or contracting telescopically in the directions of column axis.  
         [0065]     As explained above, in the present embodiment, the first lock assembly  20  and the second lock assembly  40  are provided as the lock means for locking at least the telescopic movement of the movable jacket  7 , so that the movable jacket  7  is supported at the lock assembly  20  as well as the lock assembly  40 , and thus the support rigidness is increased. Consequently, the insertion length L of the movable jacket  7  in the base jacket  6  (ref.  FIG. 1 ) is much reduced from the insertion length L′ in the case of a conventional steering apparatus  101 , shown in  FIG. 8 , (L&lt;L′), and it is possible to reduce the weight and the manufacturing cost of the steering apparatus  1 .  
         [0066]     Also, on account of the fact that the second lock assembly  40  is provided at the junction where the base jacket  6  and the movable jacket  7  are engaged with each other, it is possible to support the movable jacket  7  with the second lock assembly  40  so that the ricketiness is prevented at this junction. Furthermore, during the telescopic movement, since the second lock assembly  40  is unlocked, the sliding friction on the movable jacket  7  is minimized so that easy telescopic movement is possible.  
         [0067]     In addition, in the case of a tilt/telescopic type vehicle steering apparatus, which is capable of tilt movement and telescopic movement, like the one of the present embodiment, it is possible to simultaneously lock or unlock the telescopic movement and the tilt movement by one-touch shifting of the operation lever  27 .  
         [0068]     Incidentally, in the vehicle steering apparatus  1  according to the present embodiment, the movable jacket  7  and the distance bracket  24  rush to their foremost positions and then the adjust bracket  21 , tilt bolt  26  and the operation lever  27  shift in one body at the time of secondary shock. On this occasion, pressed by the link  46 , the sub-lever  44  swings, and the telescopic bolt  43  is unscrewed. Then, as the operation lever  27  is allowed to shift farther, the link  46  is deformed and part of the shock is absorbed therein. Optionally, an energy absorption structure may be provided between the adjust bracket  21  and the vehicle side bracket  13 .  
       USEFULNESS AND INDUSTRIAL APPLICABILITY  
       [0069]     The present invention is applicable to vehicle steering apparatuses capable at least of telescopic adjustment of the steering wheel.