Steering column for motor vehicles with a shaft movable in the axle direction

A steering column for motor vehicles with a steering shaft that is movable in the axle direction and held by a positive connection notching. The notching is formed between a jacket barrel (1) placed so that it is fixed from turning, and a solid body thrust bearing (2) and consists of toothed gearing segments (4, 5) on the width of the jacket barrel (1) and anchored toothed elements (6, 7) that are movable on the thrust bearing (2) with at least a gear tooth (9, 10). Wedge bodies (11, 12) are provided that by means of a control are movable in the bolt position brought about by the notching. The gearing tooth portions on the jacket barrel (1) include at least two segments (4, 5) developed with the same tooth spacing, that nevertheless are arranged around a half gear segment displaced with respect to each other. In addition, each segment is adjoined around a traverse axis (8) movable placed notch element (6, 7) whose gear teeth are spaced a distance from each other in the axle direction of the jacket barrel (1) that corresponds to a direct multiple of the spacing of the toothed gear segment.

FIELD OF THE INVENTION 
The invention concerns a steering column for motor vehicles with a steering 
shaft that is movable in the axle direction in which a positive connection 
notching is provided between an axially movable jacket barrel, which is 
fixed from turning and a solid body thrust bearing. 
BACKGROUND OF THE INVENTION 
In the past, it has been proposed to provide such a steering arrangement 
with a positive connection notching of the movable parts in one of the 
solid body thrust bearings with a gear element, provided mostly on the 
movable part. Such an arrangement includes a control mechanism cooperating 
with notches notches of a bolt position of a spring loaded movable notch 
element, which has at least a cog wheel element, and also more cogs. The 
positively connected notchings of the interlocking gears on the axial 
parts that move against each other are only adjustable in their final 
position. This arrangement provides the advantage that the notched bolting 
device can transmit great power in the axial direction, power that with a 
friction clamp would eventually lead to a sliding through or 
disengagement. Positive connection notchings are known to be favored from 
this standpoint to accommodate a crash force acting on the steering 
column. 
A substantial disadvantage of such a positive connection notching is 
nevertheless the "head on head" position of the interlocking gear tooth 
elements on both of the parts that unavoidably move against each other in 
an axial direction. Unaided by the performance of the sharp gear tooth 
tops, it is inevitable that such a position in the bolting device cannot 
be guaranteed. In such a case a bolting device with a definite positioning 
is achieved only through renewed pressure on the movable part (for 
example, on the steering wheel). Accordingly, with such a device, negative 
effects (including the possibility of a head on head tooth positioning) 
result that are unacceptable with regard to safety in a motor vehicle. 
With such a bolting device, a newly placed position of a traverse with a 
half segment of the gear on the notching element will occur, suggesting 
free motion for the driver of the motor vehicle. This could appear as a 
defective function. The head on head tooth position can lead to a slipping 
through of the gearing with a crash occurring adjacent the arrangement. 
This is due to the inertia of all the structural elements concerned with 
the engagement as no appreciable traverse movement to the bolting device 
occurs. 
SUMMARY AND OBJECTS OF THE INVENTION 
It is an object of the invention to develop a positive connection notching 
with characteristics of the type that a positive connection tooth 
engagement can also be achieved with a head on head tooth position of the 
individual gear elements. 
According to the invention, an axially movable jacket barrel is fixed 
against rotation and is provided with a first rack toothed segment and a 
second rack toothed segment, the first rack toothed segment having a teeth 
offset by one-half tooth width with respect to the teeth of the second 
rack toothed segment. A thrust bearing assembly is provided including a 
solid body thrust bearing. A first pawl toothed element and a second pawl 
toothed element are provided connected to the solid body thrust bearing by 
an axle extending substantially transverse to the jacket barrel such that 
each of the toothed elements is movable toward and away from a 
corresponding first and second toothed gear segment. Means are provided 
for maintaining the first and second pawl toothed elements biased in the 
direction of a corresponding first and second rack toothed segment. 
Engagement and disengagement means is provided selectively disengaging the 
bias of the first and second toothed element so as to allow disengagement 
of the first and second pawl toothed element from a corresponding first 
and second rack toothed segment. 
The arrangement according to the invention leads to a more secure tooth 
engagement in each arbitrary position. Between the limit positions, either 
a notch or toothed segment is fully engaged or the gear of another notch 
segment is fully engaged with the tooth tops on the tooth of the 
accompanying section that lies on the jacket barrel. With this 
arrangement, an endless number of intermediate positions are possible. In 
such positions the gears of both notch segments grip more or less deep in 
the gearing on the jacket barrel and support themselves on the gear 
flanks, whereby this support occurs in both segments on the facing gear 
flanks. If the gearing of a notch element also provides itself with the 
left flank on the gearing on the jacket barrel, then the gearing of the 
other gear element supports itself with the right flank on the gearing of 
the accompanying section on the jacket barrel. 
The arrangement advantageously provides a back wedging of the notch 
elements through two wedges with a self-locking angle, through which these 
wedges are loaded in the direction of the notch position through a spring 
supporting itself against both wedge bodies. This provides a bolting 
device of the movable parts that move axially against each other without a 
noticeable segmentation. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of this disclosure. For a better understanding of the invention, its 
operating advantages and specific objects attained by its uses, reference 
is made to the accompanying drawings and descriptive matter in which 
preferred embodiments of the invention are illustrated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings in particular, the invention embodied therein 
comprises a steering column arrangement with an axially movable jacket 
barrel 1 which is fixed against rotation. The axially movable jacket 
barrel 1 includes a first rack toothed segment 4 and a second rack toothed 
segment 5. The first toothed segment 4 has teeth offset by one-half tooth 
width, with respect to the teeth of the second rack toothed gear segment 
5. A thrust bearing assembly generally designated 50 is provided including 
a solid body thrust bearing tube 2, a first pawl toothed element 6 and a 
second pawl toothed element 7. Each of the pawl toothed elements (6 and 7) 
is connected to the solid body thrust bearing 2 by an axle (in the 
embodiments shown by a single axle 8). The axle 8 extends substantially 
transverse to the jacket barrel 1 such that each of the pawl toothed 
elements 6, 7 is movable toward and away from a corresponding first and 
second rack toothed segment 4, 5. Engagement, disengagement means 11-12 is 
provided for maintaining the first and second pawl toothed elements 6, 7 
biased in the direction of a corresponding first and second rack toothed 
gear segment 4, 5. The engage, disengagement means 11-12 also selectively 
disengages the bias of the first and second pawl toothed elements 6, 7 
such that they may be disengaged from the corresponding first and second 
rack toothed segments 4, 5. 
The jacket barrel 1 is arranged so that it cannot turn, which in the solid 
body thrust bearing 2 is movable in the axial direction with respect to 
central axis 3. For the bolting device of the adjusted position of jacket 
barrel 1 opposite thrust bearing 2, the rack toothed segments 4 and 5 is 
provided on a subsection of the range of jacket barrel 1. Both rack 
toothed segments 4 and 5 include a gearing in the same segmentation, but 
are arranged a half gear section removed from each other with respect to 
the axial direction. Each rack toothed segment 4 and 5 is adapted to 
engage the notch or pawl toothed element 6 and 7 respectively. The 
elements 6 , 7 are movable with respect to a common axle 8, which lies 
diagonal to axle 3. Each notch or pawl tooth element 6 and 7 respectively, 
includes at least a cog or pawl tooth 9 and 10 respectively. More cogs 
with a segment corresponding to the rack toothed segments 4 and 5 may be 
provided in which the distance of the cogs 9 and 10 still corresponds to a 
straight multiple of the rack toothed section 4 and 5. On the exterior 
both pawl toothed elements 6 and 7 operate together with wedge bodies 11 
and 12, whose wedge angle has a self-locking tendency and are loaded in 
the direction of the bolting device position through spring 13, which both 
supports itself against wedge body 11 and against wedge body 12. Both 
wedge bodies 11 and 12 are pressable against each other by overcoming the 
power of spring 13 through a control mechanism 20 (not shown in detail) so 
that they make possible a swivel movement of the notch or pawl toothed 
elements 6 and 7 around axle 8. For the reduction of the friction between 
the notch elements 6 and 7 on one hand and the wedge bodies 11 and 12 on 
the other hand the notch element rollers 18, 19 or other means of reducing 
friction can be provided for. The representation in FIG. 1 shows a 
threshold position, by which the cogs or pawl teeth 9 of a or pawl toothed 
element 6 finds itself in a "head on head" position with the gearing in 
segment 4 on jacket barrel 1. Through the removal of both rack toothed 
segments 4 and 5 in the axial direction around a half gear section the 
teeth other notch 10 on other notch or pawl toothed element 7, grip at 
least partially, in the rack teeth of rack toothed segment 5. The teeth 9 
engaging rack teeth of segment 4 entails a "head on head" position between 
rack teeth or segment 7 and pawl teeth 10, so that a tooth engagement for 
the attainment of a positive connection notching will always be attained. 
The construction example in FIG. 2 shows an embodiment viewed as in FIG. 1, 
in which every second cog or rack tooth on the segments 4 and 5 
respectively and of the pawl teeth 9 and 10 on or pawl toothed elements 6 
and 7 is missing. From this the limit positions are shown, by which the 
gearing 10 of a notch element 7 is fully locked into position, in case the 
gearing 9 on the other notch element 6 situates itself in a "head on head" 
position with the facing gearing and is overturned. In between an infinite 
number of intermediate positions are possible. In these intermediate 
positions a complete flank support of the interlocking gearing regularly 
takes place. Except in the threshold position, of which one is represented 
in FIG. 2, in all the intermediate positions of a tooth flank movement of 
pawl teeth 9 and 10 takes place on the sides lying opposite, that is, by a 
flank movement of the pawl teeth 9 on the left side of a flank movement of 
pawl teeth 10 which 20 takes place on the right side. A development 
corresponding to the example in FIG. 2 is brought about, such that through 
the regularly complete tooth engagement of the rack toothed segments 4,5 
at least of a tooth element, no great strain on the gear flanks occurs and 
a strength dimension with relative flatness on the tooth head and with a 
tooth equipped with a certain width is possible. Also by this construction 
example a back wedging of the notch elements 6 and 7 is provided for 
through wedge bodies 11 and 12, such that through a common control member 
in overcoming the force of a spring are pulled back towards each other to 
make possible a swivel movement around the pawl toothed elements 6 and 7 
around axle 8. In the bolt position represented in the FIG. 2, the wedge 
rollers 11 and 12 grip behind on the notch elements 6 and 7, whereby they 
support themselves on the solidly arranged abutments 14 and 15 that are 
also shown in the embodiment of FIG. 1. 
By a development in accordance with the example in FIG. 2, the teeth in the 
segments 4 and 5 can be arranged on the same gear segment because through 
the removal of every second cog or tooth a distance will be created, that 
is larger than the dimension of the removal corresponding to the example 
in FIG. 1. 
While specific embodiments of the invention have been shown and described 
in detail to illustrate the application of the principles of the 
invention, it will be understood that the invention may be embodied 
otherwise without departing from such principles.