Steering column arrangement
The adjustable steering column assembly addresses the challenges of secure adjustment and axial force resistance by incorporating a rack and pinion system with self-locking mechanisms, resulting in a robust and effective solution for steering column positioning and impact resistance.
Patent Information
- Application Number
- DE102024129114
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-27
- Filing Date
- 2024-10-09
- Publication Date
- 2025-04-30
AI Technical Summary
Existing steering column assemblies lack efficient mechanisms for secure and convenient adjustment of inclination and height, and they often fail to withstand axial forces effectively, particularly during impact events.
The adjustable steering column assembly features a steering shaft housed in an elongated housing, which is slidably mounted on a base member and a support bracket. The assembly includes a height adjustment mechanism with a rack and pinion system and a tilt adjustment mechanism, both with self-locking securing mechanisms that engage teeth on racks to secure the position.
The solution provides a robust and compact assembly that can withstand significant axial stress, ensuring secure locking of the steering column in adjusted positions and effective resistance to both handling and impact forces.
Smart Images
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Abstract
Description
[0001] This invention relates to steering column assemblies and, more particularly, to steering column assemblies that are both tilt and height adjustable.
[0002] The tilt and height of a steering column are usually manually adjustable to allow the steering column to be positioned safely and comfortably for the driver. It is important that the steering column can be easily unlocked, but is securely locked in place once the position of the steering column has been adjusted. Additionally, it is important that the axial position of the steering column is capable of withstanding forces acting in both directions: handling force and impact force.
[0003] According to a first aspect of the present invention, an adjustable steering column assembly comprises: a steering shaft configured at one end for attaching a steering element; an elongated steering shaft housing in which the steering shaft is mounted so as to be rotatable about its longitudinal axis; a base member relative to which the steering shaft housing is slidably mounted and forced to be displaceable in a height adjustment direction corresponding to the rotation axis of the steering shaft; a support bracket configured for attachment to a vehicle, wherein the base member is displaceable relative to the support bracket in a tilt adjustment direction; a first locking mechanism for controlling the displacement of the steering shaft housing along the height axis, comprising: a height adjustment rack member mounted on the steering shaft housing, the height adjustment rack member comprising an elongated slot and first and second racks on opposite sides of the elongated slot extending in the height adjustment direction; a pivotally mounted height adjustment locking member having two rows of teeth shaped complementary to the teeth of a respective one of the racks in the height adjustment rack members; a second locking mechanism for controlling the displacement of the base member in the inclination adjustment direction, comprising: a tilt adjustment rack member mounted with respect to the support bracket, the tilt adjustment rack member comprising an elongated slot and first and second racks having teeth on opposite sides of the elongated slot extending in the tilt adjustment direction; a pivotally mounted tilt adjustment locking member having two rows of teeth shaped complementary to the teeth of a respective one of the racks in the tilt adjustment rack members; and Actuating means for simultaneously rotating the locking element of each of the first and second securing mechanisms between a first locked position in which the first and second rows of teeth of each locking element are engaged with the first and second racks of teeth in the associated rack element, respectively, and a second unlocked position in which the first and second rows of teeth of each locking element are disengaged from the first and second racks of teeth in the associated rack element.
[0004] The present invention is simple in design and can be assembled from a small number of inexpensive components. It produces a compact, uniformly designed assembly that can be quickly redesigned for any desired column system concept. The assembly is also capable of withstanding a significant amount of axial load without failure (be it static or fatigue failure) and is highly robust. Additionally, the locking mechanisms are self-locking, and the higher the applied force, the greater the engagement between the teeth of the locking heads and the teeth of the associated racks. Furthermore, the lever kinematics (force on the locking lever) are not affected by tooth-to-tooth engagement.
[0005] The present invention also addresses some of the problems regarding the design of the known height-position locking mechanism, which were found by considering two main features. First, after adjusting the height and tilt, the present invention prevents any further movement of the steering wheel. Second, the present invention not only transfers and resists axial load from the rear to the front during an impact event, but also accommodates opposing forces acting from the front to the rear, unlike the conventional designs that were not intended to handle this loading condition. Experience has shown that the opposing force tends to occur, for example, during an airbag explosion, a rear-end collision, and when a driver attempts to lift themselves using a steering wheel.
[0006] The base member may comprise a tubular portion in which the steering shaft housing is slidably received.
[0007] The actuating means may comprise an axis.
[0008] The arrangement may include a lever for pivoting the axis.
[0009] The assembly may include a cam member mounted to the axle to adjust the orientation of a locking member.
[0010] The assembly may include a first cam member mounted to the axle for adjusting the orientation of the height adjustment locking member and a second cam member for adjusting the orientation of the tilt adjustment locking member.
[0011] The assembly may include first and second pivotally mounted cam followers engaging the first and second cam members, respectively, wherein the first cam follower is urged to pivot with the height adjustment locking member and the second cam follower is urged to pivot with the pitch adjustment locking member.
[0012] The assembly may include spring means for biasing each cam follower in a direction urging the pivotally mounted locking members toward their first locked positions.
[0013] The assembly may include a mounting member secured to the base member and on which the height adjustment locking member is pivotally mounted.
[0014] The arrangement may comprise spring means for biasing the pivotally mounted height adjustment locking member toward its first locked position.
[0015] The base element may comprise a recess in which the mounting element is received.
[0016] The mounting element may comprise a plate.
[0017] At least one of the pivotally mounted locking elements can be mounted on the axis and rotate with it.
[0018] The height adjustment locking element and the tilt adjustment locking element can be mounted on the axis and rotate with it.
[0019] The first and second rack of teeth of the tilt adjustment rack member may be arc-shaped.
[0020] The first and second locking mechanisms may be located on the same side of the height adjustment axis.
[0021] The first and second locking mechanisms may be located on opposite sides of the height adjustment axis.
[0022] The invention also includes a vehicle provided with or comprising a steering column assembly according to the first aspect.
[0023] By way of example only, specific embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a perspective, partially exploded view of a first embodiment of a steering column assembly according to the present invention; the Fig. 2(a) and (b) are perspective views from above and below, respectively, of a manually pivotable locking lever forming part of the steering column assembly of the Fig. 1 is; Fig. 3 a side view of the steering column arrangement of the Fig. 1, which shows the tilt adjustment mechanism on a larger scale; Fig. 4 a side view of the steering column arrangement of the Fig. 1, shown with a pivoting locking head removed; Fig. 5 a side view of the steering column arrangement of the Fig. 1, shown with a toothed tilt adjustment plate removed; Fig. 6 a vertical cross-section through the steering column arrangement of the Fig. 1, which shows the height adjustment mechanism; Fig. 7 is a perspective view of a housing forming part of the steering column assembly of the Fig. 1 is; Fig. Figure 8 is a perspective view of a steering column mounted in the housing of the Fig. 7 can be recorded, Fig. 9 is a perspective exploded view of a height locking mechanism forming part of the steering column assembly of the Fig. 1 is; Fig. 10 a side view of the assembled height locking mechanism of the Fig. 9 is; the Fig. 11(a) and Fig. 11(b) are side views of the operating mechanism of the height locking assembly of a second embodiment of the present invention, which is a modification of the first embodiment, each shown in situ and with the other components of the steering column assembly removed in a locked condition; the Fig. 12(a) and Fig. 12(b) Side views of the operating mechanism of the height locking assembly of the Fig. 11, each shown in situ and with the other components of the steering column assembly removed in an unlocked state; Fig. 13 is a perspective view of a third embodiment of a steering column assembly according to the present invention, which is a variation of the steering column assembly of Fig. 1 is; Fig. 14 is a perspective view of a fourth embodiment of the steering column assembly according to the present invention; Fig. 15 a side view of the steering column assembly of the Fig. 14, with section A showing the tilt adjustment lock on an enlarged scale; and Fig. 16 a side view of the steering column assembly of the Fig. 14, with section B showing the tilt and height adjustment lock on an enlarged scale.
[0024] The first embodiment of the steering column assembly 10 according to the present invention is shown in the Fig. 1 to 10 and comprises an elongated housing 12 having a cylindrical inner recess 14 in which a cylindrical steering shaft housing 16 is slidably received. A steering shaft 18 is rotatably mounted in the steering shaft housing 16. The steering shaft 18 projects longitudinally from the steering shaft housing 16, and its free end is splined, as shown in Fig. 20, for attachment of a steering wheel (not shown). The cylindrical inner recess 14, the steering shaft housing 16, and the steering shaft 18 are all coaxially aligned along a height adjustment axis X. The steering shaft 18 is normally formed in a conventional manner from two aligned shaft sections 18a, 18b (shown schematically in the Fig. 3 and Fig. 4) which are joined together by complementary splined connections to accommodate longitudinal displacement of the outer portion 18a of the steering shaft 18.
[0025] As in Fig. 1, the elongated housing 12 (and the steering shaft housing 16 and the steering shaft 18 mounted therein) are pivotally mounted with respect to a mounting bracket 22 which is mounted transversely with respect to the height adjustment axis X and which, in use, is secured to a vehicle in which the steering column assembly is to be installed. As best shown in the Fig. 1 to 4, a tilt adjustment locking plate 24 having opposite curved elongated edges 25 and mounted on a locking shaft 25 (which will be explained in more detail) is received in a complementarily shaped arcuate guide slot 26 of a guide plate 28 secured to and extending vertically downward from the lower surface of the transverse mounting bracket 22.
[0026] As in Fig. 3 and explained in more detail below, the inclination of the housing 12 (and therefore the inclination of the steering column assembly 10) can be fixed in a desired position relative to the mounting bracket 22 by engaging rows of teeth 29 extending along the curved elongated edges 25 of the locking head 30 with complementarily shaped rows of teeth 31 of a tilt locking plate 32 secured to the bracket 22 and laterally outwardly of the guide slot 26.
[0027] The locking plate 24 is generally approximately cube-shaped, although its longer opposite edges 25 are slightly curved to slide along the curved slot 26 of the guide plate 28, as described above. The rows of teeth 31 project from the curved edges 25, and each row of teeth 30 can releasably engage the corresponding row of teeth 31 on the edges of the tilt locking plate 32. As will be explained, the tilt locking plate 24 is movable between a locked position, which is Fig. 2, in which the rows of teeth 30 of the locking plate 24 engage the teeth 31 of the tilt locking plate 32, thereby fixing the inclination (bevel) of the elongated housing 12 with respect to the mounting bracket 22, and an unlocked position pivotally displaced from the orientation shown in Fig. 2, in which the teeth 30 of the locking plate 24 are disengaged from the teeth 31 of the tilt locking plate 32, allowing the inclination of the elongated housing 12 relative to the mounting bracket 22 to be adjusted.
[0028] The locking plate 24 is mounted on the locking shaft 25, which extends perpendicular to the height adjustment axis X. A cam element 39 is also mounted on the shaft and can be moved between a first locking position (in Fig. 1) and a second unlocked position by manually pivoting a claw-shaped lever 40 attached to the shaft 25. In the position of the lever 40 shown in Fig. 1, the locking plate 24 is pivoted to a position where its teeth 30 engage the respective rows of teeth 31 of the tilt locking plate 32, thereby preventing the housing 12 from pivoting in one direction or the other and thereby adjusting the tilt angle of the steering column assembly 10.
[0029] It can be seen that the maximum width of the locking plate 24 between the teeth 30 is greater than the separation of the rows of teeth 31 of the locking plate 32. If in this way in the Fig. 2, an attempt to move the housing 12 downwardly with respect to the mounting bracket 22 causes one row of teeth 30 of the locking plate 24 to more firmly engage the corresponding row of teeth 31 of the locking plate 32, and an attempt to move the housing 12 upwardly with respect to the mounting bracket 22 causes the other row of teeth 30 of the locking plate 24 to more firmly engage the corresponding row of teeth 31 of the locking plate 32.
[0030] The lever 40 can be manually moved through an angle of approximately 40° from the first extreme position, which is Fig. 1, to a second position which causes the pivotally mounted tilt lock plate 24 to be pivoted to the unlocked position in which its rows of teeth 30 at their opposite ends are disengaged from the respective rows of teeth 31 of the tilt lock plate 32, thereby allowing the housing 12 to be pivoted with respect to the mounting bracket 22 to adjust the tilt angle of the steering column assembly.
[0031] As explained below, the operation of the lever 40 controls the locking and unlocking of a height locking mechanism 46 which is in the Fig. 5 to 9 is shown.
[0032] How best to Fig. 9 and Fig. 10, the shaft 25, which is connected to the lever 40 and to the tilt locking plate 24, also carries a cam 44 for controlling the height locking mechanism 46. As best seen in the Fig. As seen in Figures 2 through 5, the height locking mechanism 46 includes a height adjustment locking plate 50 secured to the exterior of the steering shaft housing 16 at the longitudinally inner end of the housing. The plate 50 includes an elongated recess 52 whose longitudinal axis is aligned with the height adjustment axis X, and the longitudinally extending opposite inner surfaces 54, 56 of the elongated recess 52 are each provided with a respective toothed rack portion 58, 60.
[0033] The locking mechanism 46 also includes a locking head 66, which has a generally parallelogram shape and includes two identical arm portions 66a, 66b disposed on diametrically opposite sides of the locking head's rotational axis Y. The end of each of the arms 66a, 66b is formed into toothed portions 62, 64 at its opposite shorter edges, which are engageable with the complementarily shaped teeth of the rack portions 58, 60 of the plate 50.
[0034] The locking head 66 is pivotally mounted on a mounting plate 68 by means of a pivot pin 70 passing through the plate into the locking head 66, and the locking head 66 is biased toward engagement with the toothed rack portions 58, 60 by a torsion spring 72 engaging a mounting lug 73 on the laterally outer surface of the locking head 66 and the mounting plate 68. The mounting plate 68 is mounted in a recess 76 of the elongated housing 12 by means of four identical locking bolts 78. The recess 76 can also accommodate the height adjustment locking plate 50, which is secured to the outside of the steering shaft housing 16 while it moves within the housing 12. As shown in the Fig. 1 to 8, the laterally outer surface of the locking head 66 is provided with a further eyelet 79 having a concave upper surface which engages with the cam element 39 mounted on the shaft 25. By pivoting the lever 40, the cam element 39 can be moved through an angle of approximately 40° between a first extreme position, which is Fig. 9, in which the cam 39 engages the eyelet 79, and a second extreme position in which the cam 44 is rotated to push the height locking head 66 to rotate counterclockwise (as in Fig. 9) against the restoring force of the tension spring 82.
[0035] In the first extreme position, which is Fig. 9, the toothed rack portions 62, 64 of the locking head 66 engage the corresponding toothed rack portions 56, 58 of the height adjustment locking plate 50 secured to the outer surface of the steering shaft housing 16, thereby preventing the steering shaft housing 16 from being displaced in one direction or the other along the height adjustment axis X and securing it longitudinally in position.
[0036] In a similar manner to the tilt adjustment mechanism, it is observed that the maximum width of the height locking head 66 between the teeth 62, 64 is greater than the separation of the rack sections 58, 60 of the height locking plate 50. When in this manner in the Fig. 9, the locking head 66 is "wedged" or "locked" in place, an attempt to move the steering shaft housing 16 outwardly with respect to the housing 12 causes the teeth 62 of the locking head 66 to more firmly engage the corresponding rack portion 58 of the locking plate 50, and an attempt to move the steering shaft housing 16 inwardly with respect to the housing 12 causes the teeth 64 of the locking head 66 to more firmly engage the corresponding rack portion 60 of the locking plate 50.
[0037] In the second extreme position, the toothed rack portions 62, 64 of the locking head 66 are disengaged from the corresponding toothed rack portions 56, 58 of the height adjustment locking plate 50, thereby allowing the position of the steering shaft housing 16 to be adjusted in one direction or the other along the height adjustment axis X to the desired height position.
[0038] Therefore, when the lever 40 is in the first extreme position, which is Fig. 1, the shaft 25 is rotated to a position where, simultaneously, (a) the two rows of teeth 30 on the opposite edges of the pivotally mounted tilt lock plate 24 engage the respective rows of teeth 31 of the tilt adjustment lock plate 32, and (b) the toothed rack portions 62, 64 of the height lock head 66 engage the corresponding toothed rack portions 56, 58 of the height adjustment lock plate 50, thereby simultaneously preventing adjustment of the tilt and height of the steering column assembly 10.
[0039] By pivoting the lever 40 to the other extreme position as described, the shaft 25 is rotated to a position where simultaneously (a) the two rows of teeth 30 on the opposite edges of the pivotally mounted tilt lock plate 24 are disengaged from the respective rows of teeth 31 of the tilt adjustment lock plate 32, and (b) the toothed rack portions 62, 64 of the height lock head 66 are disengaged from the corresponding toothed rack portions 58, 60 of the height adjustment lock plate 50, thereby allowing simultaneous adjustment of both the tilt and height of the steering column assembly 10.
[0040] Swinging the lever 40 back to the first extreme position, which in Fig. 1, locks the selected tilt and height position of the steering column assembly 10. Securing both the tilt and height of the steering wheel assembly is of particular importance during deployment of a vehicle airbag following a rear-end collision, during which it is detected that the driver is attempting to lift himself using the vehicle's steering wheel.
[0041] A second embodiment of the present invention, which is a modification to the height adjustment mechanism, is shown in the Fig. 11 and Fig. 12. In the modification, the cam 39 described above is replaced with a generally teardrop-shaped cam follower 80 which is rotatably mounted at its wider end on the same pivot pin 72 as the locking head 66. The cam follower 80 is pivoted upwards (counterclockwise into the Fig. 11 and Fig. 12) is preloaded by a tension spring 82 extending between a mounting lug 84 on a lateral edge of the cam follower 80 and a mounting pin 86 on the housing 12. The cam follower 80 is located between the mounting plate 68 and an inner wall of the housing 12.
[0042] A cam 44, which is mounted on the shaft 25 and rotates with it, engages the cam follower 80. By pivoting the lever 40, the cam 44 can be moved through an angle of approximately 40° between a first extreme position, which is Fig. 11, in which a flat side surface 88 of the cam 44 engages the pivotally mounted cam follower 80, and a second extreme position shown in Fig. 12, in which a nose 90 of the cam 44 engages the flat surface of the cam follower 80 and pivots the cam follower 80 and the height locking head 66, which rotates therewith, against the restoring force of the tension spring 82.
[0043] Otherwise, the structure and operation of the second embodiment are identical to the first embodiment, and only the features that differ from the first embodiment have been described and illustrated.
[0044] A third embodiment of the present invention is shown in Fig. 13. The features of the third embodiment are very similar to those of the first embodiment, and corresponding features are identified with the same reference numerals increased by 100.
[0045] The only significant difference from the first embodiment is that the recess 76 in the elongated housing 12 of the first embodiment, in which the mounting plate 68 is located, is enlarged in the second embodiment to form a larger recess 176 to accommodate known features of a proprietary crash system indicated at 192 and 194. The features, construction, and operation of the second embodiment are otherwise identical to the first embodiment.
[0046] A fourth embodiment of the present invention is shown in the Fig. 14 to 16 and includes an elongated housing 212 having a cylindrical inner recess 214 within which a cylindrical steering shaft housing 216 is slidably received. A steering column 218 is rotatably mounted within the steering shaft housing 216. The steering column 218 projects longitudinally from the steering shaft housing 216, and its free end is splined, as shown at 220, for attachment of a steering wheel (not shown). The cylindrical inner recess 214, the steering shaft housing 216, and the steering column 218 are all coaxially aligned along a height adjustment axis X.
[0047] The elongated housing 212 (and the steering shaft housing 216 and the steering column 218 mounted therein) are pivotally mounted with respect to a mounting bracket 222 which is mounted transversely with respect to the height adjustment axis X and, in use, is secured to a vehicle in which the steering column assembly is to be installed.
[0048] As with the previous embodiments, the steering assembly includes a tilt adjustment and locking mechanism 229 and a height locking mechanism 246 that operate simultaneously. However, unlike the previous embodiments, the tilt adjustment and locking mechanism 229 and the height locking mechanism 246 are positioned on opposite sides of the steering column assembly 10.
[0049] One end of a claw-shaped lever 240 is attached to and rotates with a shaft 238 which extends transversely to the height adjustment axis X and which simultaneously controls the locking and unlocking of the tilt adjustment and locking mechanism 229 of the height locking mechanism 246.
[0050] As in the Fig. As seen in Figures 14 through 16, a roller 224 mounted on the shaft 238 is received in an arcuate guide recess 226 of a guide plate 228 extending downwardly from the lower surface of the transverse mounting bracket 222. As explained in more detail below, the inclination of the housing 112 can be fixed in a desired position relative to the mounting bracket 222 by means of a pivotally mounted tilt lock head 230 that releasably engages teeth of a tilt lock plate 232.
[0051] As in the previous embodiments, the tilt adjustment and locking mechanism 229 comprises a locking head 230 of general parallelogram shape, with toothed portions 233, 234 at its opposite shorter ends, engageable with the complementarily shaped teeth (which in Fig. 12 are only partially visible) facing curved rack portions 235, 236 formed at opposite inner edges of an elongated arcuate opening 237 in the tilt lock plate 238 extending from the mounting bracket 222 on the opposite side of the assembly 212 from the lever 240.
[0052] As in the previous embodiments, the tilt locking head 230 is pivotable between: (a) a locked position which is in the Fig. 12 to 14 (corresponding to the retracted or uppermost position 240a of the lever 240), in which the teeth 233, 234 of the locking head 230 engage the teeth of the rack portions 235, 236 in the inclination locking plate 32, thereby fixing an inclination of the elongated housing 212 with respect to the mounting bracket 222, and (b) an unlocked position (corresponding to the extended or position 240b of the lever 240) in which the teeth 233, 234 of the locking head 230 are disengaged from the teeth of the rack portions 235, 236 of the tilt locking plate 232, allowing the tilt of the elongated housing 212 to be adjusted relative to the mounting bracket 222.
[0053] As in the previous embodiments, it is observed that the maximum width of the locking head 230 between the teeth 233, 234 is greater than the separation of the rack portions 235, 236 of the locking plate 232. When arranged in this manner in the manner shown in the Fig. 12 to 14, the locking head 230 is "wedged" in place, an attempt to move the housing 212 downward with respect to the mounting bracket 222 causes the teeth 233 of the locking head 230 to more firmly engage the corresponding rack portion 235 of the locking plate 232, and an attempt to move the housing 212 upward with respect to the mounting bracket 222 causes the teeth 234 of the locking head 230 to more firmly engage the corresponding rack portion 236 of the locking plate 232.
[0054] As explained in more detail below, the operation of the lever 240 also controls the locking and unlocking of a height locking mechanism 246 which is in the Fig. 12 to 14 is shown.
[0055] As in the Fig. As seen in Figures 14 to 16, the shaft 238, which is connected to the lever 240, also carries a height adjustment locking plate 250, which forms part of the height locking mechanism 246 secured to the exterior of the steering shaft housing 216. The plate 250 includes an elongated recess 252 having its longitudinal axis aligned with the height adjustment axis X, and the longitudinally extending opposite inner surfaces 254, 256 of the elongated recess 252 are each provided with a respective toothed rack portion 258, 260.
[0056] The toothed rack portions 258, 260 are configured to releasably engage complementarily shaped toothed portions 262, 264 located at opposite ends of the elongated pivotally mounted height locking head 266.
[0057] The shaft 238 extends perpendicular to the height adjustment axis X and, as previously explained, can be moved between a first locking position (in the Fig. 12 to 14) and a second unlocked position by pivoting the claw-shaped lever 240, as described above. In the position of the lever 240, shown at 240a, the two sets of teeth 233, 234 at the opposite ends of the tilt lock head 230 engage the respective toothed rack portions 235, 236 of the tilt lock plate 232, thereby preventing the housing 212 from pivoting in one direction or the other and thereby adjusting the tilt angle of the steering column assembly 210.
[0058] As in the previous embodiments, it is observed that the maximum width of the height locking head 266 between the teeth 262, 264 is greater than the separation of the rack portions 258, 260 of the height locking plate 250. When arranged in this manner in the manner shown in the Fig. 12 to 14, the locking head 266 is "wedged" in place, an attempt to move the steering shaft housing 216 outwardly with respect to the housing 212 causes the teeth 262 of the locking head 266 to more firmly engage the corresponding rack portion 258 of the locking plate 250, and an attempt to move the steering shaft housing 216 inwardly with respect to the housing 212 causes the teeth 264 of the locking head 266 to more firmly engage the corresponding rack portion 260 of the locking plate 250.
[0059] The lever 240 can be moved through an angle of approximately 40° between the two extreme positions shown in Fig. 14, causing the pivotally mounted tilt lock plate 230 to be pivoted to the unlocked position in which the two sets of teeth 233, 234 at the opposite ends of the tilt lock head 230 are disengaged from the respective toothed rack portions 235, 236 of the tilt lock plate 232, thereby allowing the housing 212 to be pivoted relative to the mounting bracket 222 to adjust the tilt angle of the steering column assembly.
[0060] Therefore, when the lever 240 is in the first extreme position, which is Fig. 12, the shaft 238 is rotated to a position where, simultaneously, (a) the two sets of teeth 233, 234 at the opposite ends of the pivotally mounted tilt locking head 230 engage the respective toothed rack portions 235, 236 of the tilt adjustment locking plate 232, and (b) the toothed rack portions 262, 264 of the height locking head 266 respectively engage the toothed rack portions 256, 258 of the height adjustment locking plate 250, thereby simultaneously preventing adjustment of the tilt and height of the steering column assembly 210.
[0061] By pivoting the lever 240 to the other extreme position as described, the shaft 238 is rotated to a position where simultaneously (a) the two sets of teeth 233, 234 at the opposite ends of the pivotally mounted tilt locking head 230 are disengaged from the respective toothed rack portions 235, 236 of the tilt adjustment locking plate 232, and (b) the toothed rack portions 262, 264 of the height locking head 66 are disengaged from the corresponding toothed rack portions 258, 260 of the height adjustment locking plate 250, thereby allowing simultaneous adjustment of both the tilt and height of the steering column assembly 210.
[0062] Swinging the lever 240 back to the first extreme position, which in Fig.12, locks the selected tilt and height position of the steering column assembly 210. Securing both the tilt and height of the steering wheel assembly is of particular importance during the deployment of a vehicle airbag following a rear-end collision, during which it is detected that the driver is attempting to lift himself using the vehicle's steering wheel.
[0063] The invention is not limited to the details of the above embodiments.
[0064] The manually operated lever 40, 140, 240 can be replaced, for example, with a motor for rotating the shaft 25, 125, 238 to lock and unlock the tilt and height locking mechanism
Claims
[1] Adjustable steering column assembly comprising: a steering shaft configured at one end for attaching a steering element; an elongated steering shaft housing in which the steering shaft is mounted so as to be rotatable about its longitudinal axis; a base member relative to which the steering shaft housing is slidably mounted and forced to be displaceable in a height adjustment direction corresponding to the rotation axis of the steering shaft; a support bracket configured for attachment to a vehicle, wherein the base member is displaceable relative to the support bracket in a tilt adjustment direction; a first locking mechanism for controlling the displacement of the steering shaft housing along the height axis, comprising: a height adjustment rack member mounted on the steering shaft housing, the height adjustment rack member comprising an elongated slot and first and second racks on opposite sides of the elongated slot extending in the height adjustment direction; a pivotally mounted height adjustment locking member having two rows of teeth shaped complementary to the teeth of a respective one of the racks in the height adjustment rack members; a second locking mechanism for controlling the displacement of the base member in the inclination adjustment direction, comprising: a tilt adjustment rack member mounted relative to the support bracket, the tilt adjustment rack member comprising an elongated slot and first and second racks having teeth on opposite sides of the elongated slot extending in the tilt adjustment direction; a pivotally mounted tilt adjustment locking member having two rows of teeth shaped complementarily to the teeth of a respective one of the racks in the tilt adjustment rack members; and Actuating means for simultaneously rotating the locking member of each of the first and second securing mechanisms between a first locked position in which the first and second rows of teeth of each locking member engage the first and second racks of teeth, respectively, in the associated rack member, and a second unlocked position in which the first and second rows of teeth of each locking member are disengaged from the first and second racks of teeth in the associated rack member. [2] Adjustable steering column assembly according to claim 1, wherein the base member comprises a tubular portion in which the steering shaft housing is slidably received. [3] An adjustable steering column assembly according to claim 1 or claim 2, wherein the actuating means comprises an axle. [4] An adjustable steering column assembly according to claim 3, including a lever for pivoting the axle. [5] An adjustable steering column assembly according to claim 4, including a cam member mounted on the axle for adjusting the orientation of a locking member. [6] An adjustable steering column assembly as claimed in claim 5, comprising a first cam member mounted on the axle for adjusting the orientation of the height adjustment locking member and a second cam member for adjusting the orientation of the tilt adjustment locking member. [7] The adjustable steering column assembly of claim 6, including first and second pivotally mounted cam followers engaging the first and second cam members, respectively, wherein the first cam follower is urged to pivot with the height adjustment locking member and the second cam follower is urged to pivot with the pitch adjustment locking member. [8] An adjustable steering column assembly as claimed in claim 7, including spring means for biasing each of the cam followers in a direction urging the pivotally mounted locking members towards their first locked positions. [9] An adjustable steering column assembly according to any preceding claim, comprising a mounting member secured to the base member and to which the height adjustment locking member is pivotally mounted. [10] An adjustable steering column assembly according to claim 9, comprising spring elements for biasing the pivotally mounted height adjustment locking element towards its first locked position. [11] An adjustable steering column assembly according to claim 9 or claim 10, wherein the base member includes a recess in which the mounting member is received. [12] Adjustable steering column assembly according to one of claims 9 to 11, wherein the mounting member comprises a plate. [13] An adjustable steering column assembly according to claim 3 or claim 4, wherein at least one of the pivotally mounted locking members is mounted on and rotates with the axle. [14] The adjustable steering column assembly of claim 13, wherein at least the height adjustment locking member and the tilt adjustment locking member are mounted on the axle and rotate therewith. [15] An adjustable steering column assembly according to any preceding claim, wherein the first and second racks of the tilt adjustment rack member are arcuate. [16] An adjustable steering column assembly according to any preceding claim, wherein the first and second locking mechanisms are located on the same side of the height adjustment axis. [17] Adjustable steering column assembly according to one of claims 1 to 16, wherein the first and second locking mechanisms are located on opposite sides of the height adjustment axis. [18] A vehicle provided with or comprising a steering column assembly according to any one of the preceding claims.