Note: Descriptions are shown in the official language in which they were submitted.
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° Description
The invention relates to a trailer coupling for motor
vehicles with a tow-bar which is formed adjustable and lockable
with a positive fit between an idle position and an operating
position.
As long as trailer couplings are not used the ball-bar
protruding beyond the rear bumber disturbs. For solving this
problem trailer couplings are known whose ball-bar may be
disassembled.
Furthermore from the US document US-A-3,545,791 there is
known a trailer coupling for motor vehicles which is pivotably
mounted on the frame of a vehicle. It is 'the object of this known
device to~provide a coupling which offers the possibility for
vehicles provided with a loading platform at the rear end,' for
this coupling to be mounted on the platform without inhibiting
the normal use of the platform. For this purpose it is designed
slightly pivotable. The folding out and folding in is effected
manually.
From the French document FR-A- 2 4',~6 554 there is further
known an axially adjustable trailer coupling which is locked with
a positive fit, wherein however for assuming the end positions
the lockings must be manually released and then set again in
order to displace or turn the coupling itself.
EP-A- 0 274 788 shows a trailer coupling without a motor,
which is axially adjustable in length.
The Gez~nan patent document DE-A- 34 42 514 describes a
dismountable coupling which is axially inserted into a tube piece
on whose one end there is located a screw which can be screwed
into a corresponding inner thread of the inserted coupling in
order to secure this coupling. The rotation of the screw can for
securing be effected by motor. The Gexman Utility Model DS-U- 91
09 699.5 on the other hand shows a coupling which caa remain on
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the vehicle and is formed so that it can be folded away when not
in use . In the vertical direction as well as alternatively in the
horizontal direction this coupling is folding. For folding out,
the coupling is automatically locked by a bar which is under
spring pressure. For folding in, the bar must be manually
displaced into the opened position. In tree French document FR-A-
2,513,567 on the other hand there is shown an axially
displaceable trailer coupling which is manually displaceable by
way of a very bulky spindle-nut drive.
Generally it has been found disadvantageous with the known
trailer couplings that the design is not comfortable to operate
and demands much space.
It is the object of the invention to provide a trailer
coupling, which permits with a compact form, without physical
exertions for the trailer coupling to be brought from a secured
operating position into a non-disturbing idle position and'when
required also able again to be displaced without physical
exertion into the secured operating position.
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The invention is described in more detail by way
of a preferred embodiment form with reference to the
drawings, wherein further advantageous details can be
deduced from the drawings. The same parts with regard to
their function are provided with the same reference
numerals.
In accordance with one aspect of this invention,
there is provided a trailer coupling for motor vehicles,
comprising a towing bar formed so as to be axially
displaceable between an inoperative position and an
operating position; a spindle and nut drive for displacing
said towing bar between said positions, said towing bar
being formed as a part of said spindle and nut drive; and a
motor with which said towing bar is connected for
displacement of said towing bar, said towing bar being
formed so as to be rotatable about its axis.
In accordance with another aspect of this
invention, there is provided a trailer coupling for motor
vehicles, comprising a bar which is swivelable between an
inoperative position and a locked horizontal operating
position; and at least one drive provided for swiveling
locking and unlocking motions of said bar, said at least one
drive being formed so that it positively locks and unlocks
automatically upon swiveling into or out of said operating
position, wherein the bar is swivelable from said operating
position into said inoperative position upwardly or
horizontally by about 90°.
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The drawings show individually:
Figure 1 an elevation of the trailer coupling according to
the invention, with an axial adjustment into the
idle position,
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Figure 2 a lateral view of the trailer coupling according to the
invention and according to Figure 1,
Figure 3 a lateral view of a ball-bar according to Figure 1,
Figure 4 an elevation of a sleeve for receiving the ball-bar
according to Figure 3,
Figure 5 a lateral view of the sleeve according to Figure 4,
Figure 6 a view according to arrow A in Fig. 5,
Figure 7 a lateral view of an alternative embodiment forth with
a pivotable ball-bar,
Figure 8 a section according to line B-B of Figure 7, through
the drive of the ball-bar,
Figure 9 a lateral view of a further embodiment form with a
laterally pivotable coupling bar, and
Figure 10 a plan view of the embodiment form according. to F-figure
DETAILED DESCRIPTION OF THE INVENTION
In Figure 1 the adjustable trailer coupling is indicated at
1. It consists essentially of an axially adjustable bar 2 whose
3 outer end carries a ball 3 as well as a guiding sleeve 4, a motor
with planet gears 6, a spur gear 7 and an adjusting spindle 8.
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The guiding sleeve 4 on both sides carries in each case an
assembly flange 9 in which there are incorporated threaded bores
10. The whole trailer coupling 1 is assembled onto a vehicle in
that by way of screws it is fastened onto a suitable bracket of
the vehicle. With this screws engage into the threaded bores 10.
The bar 2 is accomodated by the guiding sleeve 4. For this
purpose the bar 2 comprises a rear guiding surface 11 and a front
guiding surface 12 which via a cone 13 blend into a somewhat
slimmer bar 2.
Furthermore in the guiding sleeve 4 an annular inner cone
14 is fastened. Finally in the guiding sleeve 4 there are formed
guiding slots 15.
On the bar 2 in the rear region there is fastened a pin-like
connecting rod 16 which engages into the guiding slot 15.
Furthermore in the bar 2 there is incorporated a pocket hole with
an inner thread 17.
The adjusting spindle 8 is screwed into the mentioned inner
thread 7 and is rotated by an electrical motor via the-spur gear
7 as well as the planet gear 6. The individual gearwheels of the
gear 7 are mounted between lateral plates 19 and 20. The housing
of the planet gear 6 and the guiding sleeve 4 are rigidly
connected to the plate 20. The adjusting spindle 8 is likewise
rotatably mounted in the plates 19 and 20 so that it can be
rotated by the electrical motor 5 as desired.
If the motor 5 is driven in the corresponding direction,
then the adjusting spindle 8 also rotates.
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At the same time the bar 2 which is arranged as a nut on the
adjusting spindle 8 and is secured against rotation by the
connecting member I6 is pushed outwards . With this axial movement
the bar 2 is guided in the guiding sleeve 4 by the guiding
surfaces 11 and 12. The bar reaches its end position when the
outer cone 13 sits rigidly in the annular inner cone 14.
As long as the guiding slots 15 run in the axial direction,
the bar 2 maintains its radial position. After roughly half the
adjusting distance the guiding slots 15 blend into a spiral-
shaped course. This results in the fact that the bar 2 on
extending then correspondingly turns so that the ball 3 in the
operating position points vertically upwards. The operating
position is shown in Figures 1 and 2 by dashed lines.
For a better understanding the essential parts are again
individually shown in Figures 3 to 6.
An alternative embodiment form of a trailer coupling is
shown in Figure 7. With this embodiment form the bar 2 is not
axially displaced, but is pivoted about an axis 24..
For an easier understanding only the bar 2 with its pivoting
drive 21 is shown, wherein known additional drive parts such as
a gear motor, are not shown.
Figure 7 shows a pivoting drive 21 with which the bar 2 can
be pivoted upwardly about approximately 90°.
The drive however can in a slightly modified form serve for
passing through other pivoting angles.
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With a correspondingly modified installation location, and
an adapted bar 42 for this, a modified pivoting drive 41 may also
be applied for a horizontal pivoting of the bar 42. Such a
pivoting drive 41 is shown in the Figures 9 and 10.
With the embodiment shown in Figure 7 the bar 2 however is
pivoted vertically upwards. For this purpose it is pivotably
mounted between two plates 22 and 23 about the axis 24 on the
pintail 25.
Furthermore the bar 2 comprises a limb 26 whose function can
be seen from Figure 8.
In Figure 8 a section corresponding to the marking effected
in Figure 7 is shown. In the region of the limb 26 the bar 2 is
thus provided with a slot 27. Furthermore perpendicular to the
plane of the slot there is provided a bearing bore 28 for the
pintail 25, a bearing bore 29 for a pinion shaft 31 as well as
a bore with an inner thread 30 for a blocking cone 32.
As mentioned the pintail 25 is rotatably mountedv' between
two plates 22 and 23. In the region of the slot 27 of the bar 2,
the pintail 25 comprises a toothing 33. A~gearwheel 34 engages
into this toothing 33, the gearwheel being mounted on the~pinion
shaft 31. With the gearwheel 34 there meshes a further gearwheel
35 which is connected to a shaft 36 in a rotatably rigid manner.
On the shaft 36 on both sides of the gearwheel 35 there is
each mounted a blocking cone 32 in a rotatably rigid but axially
displaceable manner. This blocking cone 32 comprises an outer
thread 37 which engages into the inner thread 30. For the
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blocking cone 32 a locking opening 38 is provided in the plates
22 and 23.
In the position shown in Figure 8 the blocking cone 32
should be retracted in the usual manner into the locking opening
28. For a better recognition it is shown in a position in which
the bar 2 may be pivoted.
The ends of the pinion shaft 31 are guided in arc-shaped
slots 39 of the plates 22 and 23. The remaining bores of the
plate 22 shown in Figure 7 serve for its fastening onto the
vehicle or serve the fastening of a further gear with a suitable
electrical drive or the connection by way of distance bolts.
The position of the bar 2 represented in Figure 7 with
dashed lines corresponds to its operating position. For pivoting
the bar 2 then, a gearwheel 40 rigidly connected to the pintail
25 is driven. Since firstly the blocking cone 32 is retracted
into the locking opening 38 of the plate 23, the bar 2 can still
not be pivoted about the axis 24. Instead of this via the
toothing 33 and via the gearwheel 34 the gearwheel 35 is rotated.
Since this gearwheel is rigidly connected to the shaft 36, the
shaft 36 drives the blocking cone 32. Since the outer thread 37
of the blocking cone is engaged with the inner thread 30, at the
same time the blocking cone 32 moves axially inwards until it is
completely extended out of the locking opening 38. As soon as the
blocking cone 32 comes to bear on the gearwheel 35, the gearwheel
35 and the gearwheel 34 which is engaged with it are blocked. By
way of this the pintail 25 drives the blocked gearwheel 34 and
the pinion shaft 31, so that the pinion shaft 31 is pivoted about
the axis 24. At the same time the pinion shaft 31 which is
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mounted in the bearing bore 29 of the bar 2 then drives this bar
so that the bar 2 is pivoted. This pivoting movement finishes as
soon as the pinion shaft 31 reaches the end of the slot 39.
For the purpose of clarity it must be mentioned that in
Figure 8 the left blocking cone is not shown.
For the electrical drive it is provided for this to be
switched off as soon as the land exceeds a previously set
limiting value. In this way damages are avoided, in the case that
on moving the bar 2 foreign bodies should inhibit the further
operation. So that the adjustment cannot be initiated during the
journey of the vehicle it is furthermore provided for the trailer
coupling to only be able to be operated outside the compartment
of the vehicle. It is particularly advantageous when the
operating means, for example a switch, is arranged in the boot
of the vehicle .
In this manner there is created a vehicle coupling which is
easily and comfortably brought into a position in which it no
longer disturbs.
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List of reference numerals
1 trailer coupling 33 toothing
2 bar 34 gearwheel
3 ball 35 gearwheel
4 guiding sleeve 36 shaft
motor 37 outer thread
6 planet gear 38 locking opening
7 spur gear 39 slot
8 adjusting spindle 40 gearwheel
9 assembly flange 41 pivoting drive
threaded bores 42 bar
11 guiding surface
12 guiding surface
13 cone
14 inner cone
guiding slot
16 connecting rod
17 inner thread
18
19 plate
plate
21 pivoting drive
22 plate
23 plate
24 axis
pintail
26 limb
27 slot
28 bearing bore
29 bearing bore
inner thread
31 pinion shaft
32 blocking cone
