U.S. patent application number 12/291264 was filed with the patent office on 2009-05-14 for system for opening and closing a flap.
This patent application is currently assigned to Stabilus GmbH. Invention is credited to Marian Bochen, Frank Doffing, Rolf Mintgen, Thomas Reif.
Application Number | 20090120003 12/291264 |
Document ID | / |
Family ID | 40560869 |
Filed Date | 2009-05-14 |
United States Patent
Application |
20090120003 |
Kind Code |
A1 |
Bochen; Marian ; et
al. |
May 14, 2009 |
System for opening and closing a flap
Abstract
A system for opening and closing a motor vehicle, the flap is
swivalably mounted along one of its edge areas at a stationary
structural component part about a horizontal swiveling axis. A
first drive device and a second drive device act in parallel to
more like flap from a closed position into an open position. The
first drive device is a non-self-locking drive device, and the
second drive device comprises a cylinder filled with a fluid under
pressure. An interior of the second drive device is divided by a
piston into a first work chamber and a second work chamber, wherein
a piston rod of the piston is guided outward through the first work
chamber. A valve arrangement in the piston closes a flow connection
between the first work chamber and the second work chamber in a
stationary operating state of the flap.
Inventors: |
Bochen; Marian; (Eitelborn,
DE) ; Doffing; Frank; (Kastellaun, DE) ;
Mintgen; Rolf; (Thuer, DE) ; Reif; Thomas;
(Kobern-Gondorf, DE) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE LLP
551 FIFTH AVENUE, SUITE 1210
NEW YORK
NY
10176
US
|
Assignee: |
Stabilus GmbH
Koblenz
DE
|
Family ID: |
40560869 |
Appl. No.: |
12/291264 |
Filed: |
November 6, 2008 |
Current U.S.
Class: |
49/340 ;
49/344 |
Current CPC
Class: |
E05Y 2900/546 20130101;
E05F 15/611 20150115; B60J 5/102 20130101; E05F 15/53 20150115;
E05F 15/616 20150115 |
Class at
Publication: |
49/340 ;
49/344 |
International
Class: |
E05F 15/12 20060101
E05F015/12; E05F 11/08 20060101 E05F011/08 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2007 |
DE |
10 2007 054 447.4 |
Feb 19, 2008 |
DE |
10 2008 009 898.1 |
Claims
1. A system for opening and closing a flap for a motor vehicle, the
flap being mounted along one of its edges at a stationary
structural component of the motor vehicle so as to be swivelable
around a swiveling axis so as to be movable between a closed
position and an open position, the system comprising: a first
non-self-locking drive device coupled between the flap and the
stationary structural component, the first drive device being an
electromechanical drive device; and a second drive device acting in
parallel with the first drive device, the second drive device being
one of a hydraulic, pneumatic, and hydropneumatic drive device, the
second drive device comprising: a cylinder having a first closed
end articulated at one of the stationary structural component part
and the flap at a distance from the swiveling axis, the cylinder
being at least partially filled with a fluid under pressure; a
piston that divides an interior of the cylinder into a first work
chamber and a second work chamber; a piston rod coupled to the
piston, the piston rod being guided outward through and out of the
first work chamber articulated at the other of the flap or the
stationary structural component part at a distance from the
swiveling axis; a sealing and guiding package adapted to guide the
piston rod through and out of the first work chamber; and a valve
arrangement forming a flow connection between the first work
chamber and the second work chamber, wherein the valve arrangement
is closed when the flap is stationary.
2. The system for opening and closing a flap according to claim 1,
wherein the first drive device is arranged at a first edge area of
the flap and the second drive device is arranged at a second edge
area of the flap, each edge extending at substantially a right
angle from the swiveling axis.
3. The system for opening and closing a flap according to claim 1,
wherein the flap is one of a hatchback, a trunk hood, and an engine
hood.
4. The system for opening and closing a flap according claim 1,
wherein the flap is supported along an edge area so as to be
substantially vertical in the closed position and substantially
horizontally in the open position.
5. The system for opening and closing a flap according claim 1,
wherein the first drive device comprises: a rotary drive; a
threaded spindle coupled to the rotary drive and adapted to
rotatably drive the threaded spindle, the threaded spindle coupled
to one of the flap and the stationary structural component part;
and a spindle nut arranged on the threaded spindle coupled to the
other of the stationary structural component part and the flap.
6. The system for opening and closing a flap according to claim 5,
further comprising a non-self-locking gear unit coupled between the
threaded spindle and the rotary drive.
7. The system for opening and closing a flap according to claim 5,
wherein the rotary drive is an electric motor.
8. The system for opening and closing a flap according to claim 5,
further comprising a tubular housing in which at least the rotary
drive, the threaded spindle, and the spindle nut are arranged.
9. The system for opening and closing a flap according to claim 5,
further comprising a spindle tube adapted to enclose the threaded
spindle, the spindle tube being connected to the spindle nut at its
axial end closer to the rotary drive and is coupled to one of the
stationary structural component part and the flap at its axial end
remote of the rotary drive.
10. The system for opening and closing a flap according to claim 8,
further comprising a protective tube connected to the spindle nut
on the end area of the tubular housing remote of the rotary drive
coupled to the stationary structural component part or flap by its
end remote of the rotary drive.
11. The system for opening and closing a flap according to claim 1,
wherein the second drive device is a gas spring, the first work
chamber and second work chamber being filled with a gas under
pressure.
12. The system for opening and closing a flap according to claim
11, further comprising a piston rod extension extending from the
end of the piston rod, wherein the piston, the piston rod, and the
piston rod extension are arranged coaxial to the cylinder.
13. The system for opening and closing a flap according to claim
12, further comprising a second piston arranged at the end of the
piston rod extension.
14. The system for opening and closing a flap according to claim
13, wherein the piston has a closing spring and the second piston
has a second closing spring, wherein the closing springs having
substantially identical or different spring forces.
15. The system for opening and closing a flap according to claims
1, wherein the cylinder of the second drive device has a dividing
piston, the dividing piston being axially displaceable in the
cylinder defining a partial space between the closed end of the
cylinder and the second work chamber in the cylinder, wherein the
partial space is filled with a gas under pressure.
16. The system for opening and closing a flap according to claims
15, wherein the first work chamber and second work chamber are
filled with an incompressible fluid.
17. The system for opening and closing a flap according to claims
16, wherein the incompressible fluid is an oil.
18. The system for opening and closing a flap according to claim 1,
wherein the valve arrangement includes a closing valve having a
valve element by which three switching positions can be occupied,
wherein, proceeding from a middle closed switching position, a
first opening position can be occupied by the valve element in one
direction and a second open position can be occupied by the valve
element in the other direction.
19. The system for opening and closing a flap according to claim 1,
wherein the valve arrangement is an electrically controllable
magnetic valve.
20. The system for opening and closing a flap according to claim
19, wherein the magnetic valve is powered on so as to open the flow
connection between the first work chamber and the second work
chamber by controlling the first drive device for the flap
adjustment.
21. The system for opening and closing a flap according to claim
20, wherein the valve arrangement is arranged in the piston.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a system for opening and closing a
flap for a motor vehicle mounted along one of its edge areas to a
stationary structural component so as to be swivelable around a
horizontal swiveling axis. The flap is driven by a first drive
device and a second drive device acting in concert so as to be
movable from a closed position into an open position, wherein the
first drive device is an electromechanical drive device and the
second drive device is a hydraulic, pneumatic, or hydropneumatic
drive device.
[0003] 2. Description of the Related Art
[0004] Opening and closing systems for vehicle flaps are known for
opening and closing flaps such as hatchbacks, trunk lids, engine
hoods, doors, and the like in motor vehicles. Often, both sides of
the flap are driven electromechanically so as to prevent warping of
the flaps when the flaps are open and closed.
[0005] Some drive systems are used that drive the flaps
electromechanically on only one side, while a gas spring is
arranged at the other side of the flap. The gas spring
counterbalances the weight of the flap by substantially supporting
only the opening of the flap. An opening and closing system of this
kind is generally better than the variant that is driven
electromechanically on both sides and is therefore preferred for
installation in most applications.
[0006] In systems that are driven electromechanically on one side
it is disadvantageous that the electromechanical drives are
outfitted with pressure springs, typically embodied as helical
pressure springs, which must counterbalance the weight of the flap
so that the motor has reasonable dimensions in terms of the vehicle
construction and the flap can be safely held in a partially closed
position or in the completely open position.
[0007] Further, it is disadvantageous with respect to installation
space when the flap is stopped in desired positions by other
braking elements or clamping elements.
SUMMARY OF THE INVENTION
[0008] Therefore, it is an object of the invention to provide an
opening and closing system for flaps that overcomes the
disadvantages described above and has a simple, space-saving
construction with few structural component parts.
[0009] According to one embodiment of the invention, the first
drive device is a non-self-locking drive device and the second
drive device comprises a cylinder that is filled with a fluid under
pressure and whose closed first end is connected to the stationary
structural component part or flap at a distance from the swiveling
axis. The interior of the second device is divided by a piston into
a first work chamber and a second work chamber, wherein a one-sided
piston rod of the piston is guided outward through the first work
chamber and out of the first work chamber so as to be sealed by a
sealing and guiding package and is connected to the flap or
stationary structural component part at a distance from the
swiveling axis, with a valve arrangement by which a flow connection
between the first work chamber and the second work chamber is
closed in a stationary operating state of the flap.
[0010] The flow connection between the first work chamber and the
second work chamber is opened during a movement of the flap so that
a fluid balance is achieved between these two work chambers.
[0011] When flap movement is concluded, the flow connection is
closed and the flap is held in its occupied position.
[0012] The first drive device is preferably arranged at a first
edge area of the flap and the second drive device is preferably
arranged at a second edge area of the flap, which proceeds at least
approximately at right angles from the swiveling axis.
[0013] This configuration limits warping of the flap due to an
imbalanced application of force.
[0014] The flap can be a hatchback, a trunk hood, engine hood, or
the like in the motor vehicle.
[0015] The flap is preferably supported along its upper edge area
so as to be swivelable around the swiveling axis and is directed
substantially perpendicularly downward in the closed position and
substantially horizontally in the open position.
[0016] Because a fluid equilibrium is blocked when the flow
connection is closed, the flap remains securely held in its
occupied position even in horizontal orientation.
[0017] It is particularly economical in terms of space when the
first drive device has a spindle drive driven in rotation by a
rotary drive and which has a threaded spindle that is connected to
the flap or to the stationary structural component part, and a
spindle nut that is arranged on the threaded spindle that is
connected to the stationary structural component part or to the
flap.
[0018] To reduce the rotating speed of the rotary drive, the
threaded spindle is driven in rotation by the rotary drive by a
non-self-locking gear unit. Due to the non-self-locking
construction of the gear unit, as well as the non-self-locking
construction of the entire drive device, the flap is easily moved
by hand when the first drive device is not activated. The rotary
drive is preferably an electric motor.
[0019] When the rotary drive, threaded spindle, spindle nut and,
the gear unit are all preferably arranged in a tubular housing, a
compact constructional unit is achieved which protects these
components.
[0020] A spindle tube preferably encloses the threaded spindle with
play and is connected to the spindle nut by its axial end that is
closer to the rotary drive and can be articulated at the stationary
structural component part or the flap by its end remote of the
rotary drive.
[0021] In a preferred embodiment, the protective tube is arranged
so as to be displaceably guided on the end area of the tubular
housing remote of the rotary drive and is connected to the spindle
nut and articulated at the stationary structural component part or
flap by its end remote of the rotary drive, the part of the system
that is movable in a telescoping manner relative to the tubular
housing is also externally protected.
[0022] In one embodiment, the second drive device is a gas spring
and the first work chamber and second work chamber are filled with
a gas under pressure. The gas acting upon the larger effective
surface of the piston generates the push-out movement of the piston
rod.
[0023] In one embodiment of the invention, a piston rod extension
extends farther in the direction of the first end of the cylinder,
opposite the end of the piston rod located in the cylinder.
Preferably, the piston is arranged coaxial to the cylinder.
[0024] A second piston is preferably arranged at the end of the
piston rod extension. The second piston is a mirror image of the
first piston.
[0025] The two pistons have a closing spring with identical or
different spring forces.
[0026] In one embodiment, the cylinder of the second drive device
has a flexible wall, particularly a dividing piston that is axially
displaceable in the cylinder so as to be sealed. This defines a
partial space between the closed end of the cylinder and the second
work chamber in the cylinder. The partial space is filled with a
gas under pressure, and the first work chamber and second work
chamber are filled with an incompressible fluid, preferably an
oil.
[0027] The flexible wall, holds the fluid under pressure in the
second work chamber in conjunction with the gas that is under
pressure to generate the push-out movement of the piston rod by the
greater effective surface of the piston.
[0028] In one embodiment, the valve arrangement has a closing valve
with a valve element by which three switching positions can be
occupied, wherein, proceeding from a middle closed switching
position, a first opening position can be occupied by the valve
element in one direction and a second open position can be occupied
by the valve element in the other direction.
[0029] For a further development of this closing valve, reference
is made to U.S. Pat. No. 5,988,608 whose disclosure is incorporated
by reference.
[0030] In another embodiment, the valve arrangement has an
electrically controllable magnetic valve, wherein the magnetic
valve is powered on to open the flow connection between the first
work chamber and the second work chamber by controlling the first
drive device for the flap adjustment.
[0031] The valve arrangement can be arranged at any suitable
location of the second drive device.
[0032] When the valve arrangement is arranged in or at the piston,
installation space is minimized.
[0033] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of the disclosure. For a better understanding
of the invention, its operating advantages, and specific objects
attained by its use, reference should be had to the drawing and
descriptive matter in which there are illustrated and described
preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Embodiment examples of the invention are shown in the
drawings and are described more fully in the following.
[0035] FIG. 1 shows a schematic view of a motor vehicle with a
swivelably driven hatchback;
[0036] FIG. 2 shows an embodiment form of an electromechanical
drive according to the invention;
[0037] FIG. 3 shows an embodiment form of a hydropneumatic drive
according to the invention;
[0038] FIG. 4 shows embodiment form of a hydropneumatic drive;
[0039] FIG. 5 shows embodiment form of a hydropneumatic drive;
[0040] FIG. 6 shows embodiment form of a hydropneumatic drive;
and
[0041] FIG. 7 shows embodiment form of a hydropneumatic drive.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0042] FIG. 1 is a schematic view of a motor vehicle with a car
body as a basic part 1 and a movable part 3 which closes or opens
an aperture 2 in the basic part 1 and which is constructed as a
hatchback, hereinafter flap 3. The flap 3 can also be a front hood,
an engine hood, a vehicle door, or the like.
[0043] The flap 3 is preferably mounted in a horizontal swiveling
axis 4 extending transverse to the vehicle. It should be noted that
the swiveling axis need not be horizontal but many, for example, be
vertical or any other angle. A first drive device 5 is arranged at
one side of the flap 3 and a second drive device 6 is arranged at
the opposite side of the flap 3.
[0044] FIG. 2 depicts one of the two drive devices, embodied as an
electromechanical drive device, which is associated with the first
drive device 5 in the following description for the sake of
simplicity. It should be noted that the drive device shown in FIG.
2 may alternatively be associated with second drive device 6.
[0045] The first drive device 5 has a tubular housing 7 that is
closed at one end by a base piece 8. The base piece 8 has a
threaded pin 9 on which a connection element 10 is screwed.
[0046] The housing 7 has a first portion 11, a second portion 12,
and a third portion 13. The first portion 11 has a larger inner
diameter than second portion 12 while its outer diameter preferably
remains the same. Third portion 13 has a larger outer diameter than
second portion 12 while the inner diameter remains the same.
[0047] A protective tube 14 whose outer diameter substantially
corresponds to the outer diameter of the second portion 12 of the
housing 7 is arranged over third portion 13 of the housing 7. The
protective tube 14 is closed by a base piece 15 at a remote and of
the housing 7. The base piece 15 has a threaded pin 16 on which a
second connection element 17 is screwed.
[0048] The connection elements 10 and 17 include a ball socket, as
is shown in FIG. 2, but knuckle eyes or the like can also be used.
In one embodiment, the connection element is integral with the base
piece or connected by other connection techniques such as welding,
or creasing, or the like so that the first drive device 5 is
connected in an articulated manner to a stationary structural
component part of the body or to the basic part 1 of a motor
vehicle and to a movable structural component part of the motor
vehicle that is constructed as a flap 3.
[0049] A rotary drive 18 is arranged inside the housing 7 in the
first portion 11. The rotary drive 18 comprises an electric motor
19, a sensor device in a sensor housing 20, and a gear unit 22 in a
gear unit housing 21. The electric motor 19 is supported by the
sensor housing 20 at the end of the housing 7 that is closed by the
base piece 8. The gear unit housing 21 is supported at the electric
motor 19 by an adapter element 23. The gear unit 22 arranged in the
gear unit housing 21 is driven by a motor driveshaft 24. Further,
the motor driveshaft 24 projects into the sensor housing 20 on the
side opposite the gear unit housing 22. The electrical connection
lines, not shown, comprising the power supply lines and control
lines extend from the sensor housing 20, through the base piece 8
and out of the housing 7.
[0050] The gear unit housing 21 is closed at the side opposite the
electric motor 19 by a housing cover 25 through which a gear unit
shaft 26 extends. The end of the gear unit shaft 26 is connected to
a spindle drive. An adapter insert 27 to which a spindle adapter 28
is arranged is located at the end of the gear unit shaft 26. A
threaded spindle 29 is connected to the gear unit shaft 26 by the
adapter insert 27 and spindle adapter 28.
[0051] The spindle adapter 28 is supported in a bearing 30. The
bearing 30 is in turn arranged in a bearing sleeve 31 which is
supported at the gear unit housing 22 or housing cover 25 on one
side and contacts a step 32 on the other side, which step 32 is
formed by the different inner diameters of portions 11 and 12.
Accordingly, the rotary drive 18 is fixed together with the bearing
30 of the threaded spindle 29 in axial direction inside the first
portion 11 of the housing 7. Part of the rotary drive 18 can be
connected to the housing 7 by screws 33 or catches in such a way
that they cannot rotate relative to the housing.
[0052] A spring sleeve 34 is supported at the bearing 30 or at the
bearing sleeve 31 located substantially in the second portion 12 so
as to contact the inner wall of the housing 7. A wall 35 with a
bore hole 36 is formed in the interior of the spring sleeve 34. The
threaded spindle 29 extends through bore hole 36. The spring sleeve
34 is lengthened by a guide tube 37 to the end of the housing 7
proceeding from the second portion 12 of the housing 7 in direction
of the third portion 13. Spring sleeve 34 and guide tube 37 each
have, at their sides contacting one another, projections 38 and
complementary recesses 39 and are accordingly arranged so as to be
fixed with respect to rotation relative to one another. Further,
the guide tube 37 has at least one groove 40 which extends in axial
direction and which can also be constructed as a slot, and a
projection 42 formed at a spindle nut 41 projects into this groove
40.
[0053] A spring device 43 which partially surrounds the threaded
spindle 29 extends from the side of the wall 35 remote of the
bearing 30 in direction of the third portion 13 of the housing 7
and makes contact with the spindle nut 41 running on the threaded
spindle 29, in particular when the first drive device 5 is
inserted, i.e., when the flap 3 is in its almost fully closed
position. The spring device 43 urges the spindle nut 41 away from
the wall 35 when opening the flap 3 out of its completely closed
position and the rotary drive 18 therefore supports at least the
first centimeter of the flap-opening movement.
[0054] An axially movable spindle tube 44 is guided with the
spindle nut 41 in the guide tube 37 and is arranged with one end at
the spindle nut 41 and with its other end at the base piece 15 of
the protective tube 14. The threaded spindle 29 has, at the end
near the base piece 15, a guide ring 45 that is arranged in the
spindle tube 44 to prevent radial swiveling of the threaded spindle
29.
[0055] Another guide ring 46 is arranged between the spindle tube
44 and the end of the housing 7 near the connection element 17,
which also prevents a radial swiveling of the structural component
parts that move in a telescoping manner and forms a stable
protection against buckling.
[0056] FIG. 3 shows an example of a drive device in the form of a
piston-cylinder unit 47, which is preferably associated with the
second drive device 6.
[0057] The piston-cylinder unit 47 is preferably constructed as a
gas spring and is filled with a gaseous medium under pressure. The
piston-cylinder unit 47 comprises a cylinder 48 with a closed first
end 49 and a second end 50 located opposite the closed end. A
piston rod 51 arranged coaxial to the cylinder 48 is guided out of
the cylinder 48 through the second end 50 by a sealing and guiding
package 52. Connection devices 53 and 54 are arranged at the closed
end 49 of the cylinder and at the end of the piston rod 51 lying
outside of the cylinder. The connection devices 53, 54 can receive
connection elements, not shown, such as ball sockets, knuckle eyes,
or the like.
[0058] A piston 55 divides the piston-cylinder unit 47 into a first
work chamber 56 on the piston rod side and a second work chamber 57
remote of the piston rod arranged at the end of the piston rod 51
located in the cylinder 48. The piston 55 comprises a stationary
guide sleeve 58, which has a circumferential supporting edge 59 for
a closing spring 60. The closing spring 60 biases a slide 61,
centered with a slide sleeve 62, on the guide sleeve 58. The
closing spring 60 acts on a circular slide surface 63 whose axial
end portion cooperates with a sealing ring 64. The sealing ring 64
forms an axially movable valve element that occupies various
switching positions on a valve ring 65.
[0059] The outer surface of the valve ring 65 is contoured, which
in one embodiment, makes possible three switching positions.
Considered from the slide surface 63, the valve ring 65 has a first
valve seat surface in the form of an inclined surface 66, a second
valve seat surface in the form of a clamping surface 67, and a
third valve surface in the form of an inclined surface 68. It
should be noted that additional surfaces are provided in other
embodies to provide additional switching positions. A stop ring 69
clamps the entire construction of the piston 55. A valve ring seal
70 prevents leakage between the pin of piston rod 51 and the valve
ring 65.
[0060] To allow the medium to flow faster into the area of the
cylinder 48 in which the piston 55 is located when the flap 3 is
almost closed so as to ensure a more powerful lifting out of the
closed position of the flap 3 and falling into the flap lock, a
groove 71 extending in axial direction is preferably formed in the
cylinder.
[0061] FIG. 4 shows another second drive device. In many respects,
this embodiment corresponds to the embodiment shown in FIG. 2.
Therefore, identical structural component parts are provided with
the same reference numbers and are not described in more
detail.
[0062] In contrast to the piston-cylinder unit 47 shown in FIG. 2,
a dividing piston 72 divides the second work chamber 57 remote of
the piston rod into a first partial space 73 in the vicinity of the
first end 49 of the cylinder 48 and a second partial space 74
remote of the first end 49. The first partial space 73 is filled
with a gas under pressure, while the first work chamber 56 and the
second partial space 74 are filled with oil. A sealing ring 75 is
inserted into a groove 76 of the dividing piston 72 so that the oil
and gas do not mix.
[0063] To allow the oil to flow faster into the area of the
cylinder 48 in which the piston 55 is located when the flap 3 is
almost closed, a groove 71 extending in an axial direction is
formed in the cylinder 48. Groove 71 is located substantially in
the second partial space 73 near the dividing piston 72. However, a
sufficient distance is provided so that the dividing piston 72
cannot be displaced over groove 71.
[0064] FIG. 5 shows another second drive device 6. In many
respects, this embodiment corresponds to the embodiment shown in
FIG. 3. Therefore, identical structural component parts are
provided with the same reference numbers and are not described in
more detail.
[0065] A piston rod extension 51a extends coaxial to the cylinder
48 from the end of the piston rod 51 lying in the cylinder 48 and
the piston 55 arranged at the latter farther in direction of the
first end 49 of the cylinder 48. A piston 55a has the same
construction and the same shape as piston 55 but opposite
orientation, and is arranged at the end of the piston rod extension
and divides the second work chamber 57 again. The third work
chamber located opposite from the piston rod extension 51a is
designated by reference number 57a.
[0066] In contrast to the piston-cylinder unit 47 shown in FIG. 2,
a first area 71a in which there is no groove is formed near the
first end 49 and a second area 71b in which there is no groove is
formed near the sealing and guiding package 52. The groove 71
extends between first area 71a and second area 71b in an axial
direction. The axial dimension of the areas 71a, 71b without
grooves and of groove 71 or of the piston rod extension 51a is
determined by the application. For example, in one embodiment the
piston rod extension 51a is longer in axial direction than the
stroke path of the piston rod 51 so that piston 55 and piston 55a
never reach the same point inside the cylinder 48. Further, the
first area 71a in which there is no groove is long enough so that
the piston 55a cannot move to the first end 49 of the cylinder 48
when the flap 3 is completely closed. Of course, other variations
will be apparent to the person skilled in the art.
[0067] FIG. 6 shows another second drive device 6. Piston-cylinder
unit 47 is similar to the piston cylinder of 47 shown in FIGS. 3
and 4. A spring receiving part 77 is arranged at the end of the
piston rod 51 projecting out of the cylinder 48 and another spring
receiving part 78 is arranged at the first end 49 of the cylinder
48. A helical pressure spring 79 is fixed coaxially around the
cylinder 48 by the two spring receiving parts 77 and 78.
[0068] The following describes operation of the first and second
drive devices 5 and 6. When the flap 3 is opened from its
completely closed position, the threaded spindle 29 of the first
drive device 5 is set in rotational movement by the rotary drive 18
so that the spindle nut 41 is moved over the threaded spindle with
the assistance of the spring device 43 so that the housing 7 and
the protective tube 14 are displaced so that they can telescope
relative to one another.
[0069] At substantially the same time, the piston 55 of the
piston-cylinder unit 47 shown in FIG. 3 is displaced in direction
of the second end 50 because of the pressure conditions in the
cylinder 48 so that the piston rod 51 is moved out of the cylinder
48. A relatively large amount of medium can flow from the first
work chamber 56 into the second work chamber 57 through the groove
71. In addition, the sealing ring 64 is displaced in the area of
the inclined surface 68 so that additional flow openings are
released.
[0070] The flap 3 can stop at any desired point in its swiveling
path and the electric motor is switched off. The electric motor 19
and the gear unit 22 are not self-locking so friction is low.
Movement of the flap 3 is possible by manually applying force to
the flap 3. The flap attempts to move down into the closed position
because of its own weight. However, the sealing ring 64 is moved on
the clamping surface 67 because of the pressure conditions
prevailing in the cylinder 48 so that the gas, preferably nitrogen,
can no longer flow from the first work chamber 56 into the second
work chamber 57 in the cylinder 48. The flap 3 does not move from
of its completely closed position.
[0071] When the flap 3 is moved farther towards of its completely
open position, whether by applying manual force or by means of the
first drive device 5, the sealing ring 64 is moved into the area of
the inclined surface 68 and the gas can flow again from the first
work chamber 56 into the second work chamber 57.
[0072] However, if the flap 3 is moved towards its completely
closed position, either by manual force or by the first drive
device, the piston rod 51 is pushed into the cylinder 48 and the
sealing ring 64 is supported at the end portion of the slide
surface 63. The sealing ring 64 is pressed against the slide 61 by
the pressure in the second work chamber 57 and by the frictional
force between the cylinder 48 and the sealing ring 64. When the sum
of the frictional force and pressure force is greater than the
closing force of the closing spring 60, the slide 61 together with
the sealing ring 64 moves in direction of the connection device 54.
The gas can flow out of the second work chamber 57 into the first
work chamber 56 through a gap formed by the inclined surface 66 and
the sealing ring 64.
[0073] When the piston rod 51 is not pushed in any farther, the
sealing ring 64 is pressed back on the clamping surface 67 again by
the pressure conditions prevailing in the second cylinder 48 and by
the closing spring 60.
[0074] The piston-cylinder unit 48 of the drive device 6 shown in
FIG. 4 also functions in a similar manner. As was already described
above, only the first partial space 73 of the second work chamber
57 is filled with a gas under pressure, whereas the first work
chamber 56 and the second partial space 74 of the second work
chamber 57 are filled with oil. Owing to the fact that the first
partial space 73 is under pressure and the dividing piston 72 is
forced against the oil column, the piston rod 51 attempts to move
in the extended direction because of the pressure conditions and
surface ratios. The switching of the sealing ring 64 follows the
same principles as the piston-cylinder unit described above with
reference to FIG. 3.
[0075] In the embodiment, form of the drive device 6 shown in FIG.
5, in the closed state of the flap 3 the piston 55 is in the area
of the groove 71 and the piston 55a is in the first area 71a in
which there is no groove. When the flap 3 is opened, the piston 55a
acts in the same way as was described in the closing direction with
reference to FIG. 3. The piston 55 is ineffective as long as it is
moved in the extended direction. The push-out force acting on the
piston rod 51 in the first area 71a without the groove includes the
gas force acting on the effective surface of the piston 55a and the
generated holding force of the closing spring 60a of the piston
55a. When the sealing ring 64a of the piston 55a reaches the groove
71, the medium located in the interior of the cylinder 47 flows
around the sealing ring 64a and the piston 55a acts like a
conventional piston and supports the piston rod 55 moving out of
the cylinder 47.
[0076] In the almost completely open position of the flap 3, the
piston 55 is moved into the second area 71b in which there is no
groove and functions in the opening direction in the same way as
described referring to FIG. 3. If the flap 3 is stopped, the
sealing ring 64 is moved on the clamping surface 67 because of the
pressure conditions prevailing in the cylinder 48, so that the gas
in the cylinder 48 can no longer flow from the first work chamber
56 into the second work chamber 57. The weight of the flap 3 by
itself is not sufficient to move toward of its completely closed
position. When the flap is completely open, the piston 55a is
located in the area of the groove 71 and the piston 55 is located
in the second area 71b in which there is no groove.
[0077] When closing the flap 3 by manual force or by means of the
first drive device 5, the piston 55 acts in the closing direction
in the same way as described referring to FIG. 3. The piston 55a
acts like a conventional piston by which, because of the pressure
conditions prevailing in the cylinder and the effective surface of
the piston 55a, the piston rod is moved into the cylinder 47
against the moving-out force generated in this way. When the piston
55a arrives in the first grooveless area 71a, it acts in the
opening direction of the flap 3 as was described with reference to
FIG. 2 or in the moving-out direction of the piston rod 51. If the
flap 3 is stopped, the sealing ring 64a moves on the clamping
surface 67a because of the pressure conditions prevailing in the
cylinder 48 so that the gas in the cylinder 48 can no longer flow
from the third work chamber 57a into the second work chamber
57.
[0078] The closing springs 60 and 60a installed in the pistons 55
and 55a can have different or identical spring forces in order to
achieve different switching behavior of the piston in the push-out
or push-in directions.
[0079] Further, the helical pressure spring 79, which is shown in
FIG. 6 arranged coaxially around the piston-cylinder unit 47,
increases the extension force of the piston-cylinder unit 47 and
compensating for temperature-dependent pressure changes inside the
cylinder 48.
[0080] FIG. 7 shows another embodiment of the second drive device
6, parts of which correspond to the embodiment shown in FIG. 3.
[0081] The piston-cylinder unit comprises a closed cylinder 248,
which is preferably filled with an incompressible fluid under
pressure. The interior of the cylinder 248 is divided into a first
work chamber 256 and a second work chamber 257 by a piston 255,
which is axially displaceable in the cylinder 248. A piston rod 251
is arranged at one side of the piston 255 and is guided through the
first work chamber 256 and outward at the seal end 250 of the
cylinder 248. A passage 80 leading from the first work chamber 256
to the second work chamber 257 can be opened and closed by an
electrically controllable magnetic valve 81.
[0082] The end of the piston rod 251 projecting into the cylinder
248 is provided with a coaxial threaded bore hole, 82a (shown in
dotted lines), in which a bolt-shaped coil core 82 having a smaller
diameter than the piston rod 251 is screwed in by its end which is
provided with a thread so that the coil core 82 forms a coaxial
extension of the piston rod 251. Other connection possibilities
such as, e.g., welding, are also conceivable.
[0083] An electrically insulating spacer disk 83 of is arranged on
the end of the piston rod 251 projecting into the cylinder 248 and
engages around the end of the piston rod on the radial inner side.
An insulating ring 84 is arranged on the coil core 82 so as to
contact the spacer disk 83 axially and is contacted axially in turn
by an annular disk 85 of steel which extends radially outward into
the vicinity of the inner wall of the cylinder 248.
[0084] An electrically insulating coil carrier 86 preferably
encloses the coil core 82 and is arranged on the coil core 82 on
the side of the disk 85 remote of the insulating ring 84 and
contacts the disk 85 axially by a radial flange 87. A coil 90 to
which current can be applied is located between two radial flanges
88 and 89 of the coil core 86 which are arranged at a distance from
one another.
[0085] A circular disk 91 of paramagnetic material is preferably
fixedly arranged on the end of the coil core 82 which is remote of
the piston rod 251 and which projects out of the coil carrier 86,
this circular disk 91 contacting the coil carrier 86 axially by one
of its ends and holding the latter in contact with the disk 85 by
its flange 87.
[0086] The circular disk 91 extending radially to the vicinity of
the inner wall of the cylinder 248 is formed with continuous axial
openings 92 which are arranged so as to be uniformly distributed on
a concentric circle, and the free ends of correspondingly axially
extending pins 93 of a circular-cylindrical piston part 94 of
paramagnetic material project into the axial openings 92 and are
fastened. The piston part 94 is guided in the cylinder 248 so as to
be axially displaceable and has an annular groove 95 at its
radially circumferential outer surface.
[0087] Two guide rings 96 of electrically nonconductive material
are inserted into the annular groove 95 at the two axial ends in
such a way that they extend radially until contacting the inner
wall of the cylinder 248 for axially guiding the piston part
94.
[0088] A sealing ring 97 is inserted into the annular space of the
annular groove 95 formed axially between the two guide rings 96 and
contacts the inner wall of the cylinder 248 with its outer radially
circumferential annular surface and seals the two work chambers 256
and 257 relative to one another.
[0089] The coaxially continuous passage 80 is formed in the piston
part 94 and its opening facing the coil core 82 forms a valve seat
98.
[0090] A disk-like armature 99 with axial play is arranged so as to
be movable axially between the front side of the piston part 94,
from which the pins 93 protrude axially, and the free end of the
coil core 82. The disk-like armature 99 carries on its side facing
the valve seat 98 a valve closing member 100 which is formed as an
elastomer part and by which the passage 80 is closed when
contacting the piston part 94 axially.
[0091] The disk-shaped armature 99, which extends radially to the
vicinity of the inner wall of the cylinder 248, has axial recesses
101 corresponding to the pins 93 which project through these axial
recesses 101.
[0092] Accordingly, the armature 99 is guided on the pins 93 so as
to be axially displaceable. The armature 99 is acted upon with its
valve closing member 100 axially against the valve seat 98 by a
pretensioned pressure spring, which is supported at the circular
disk 91 and constructed as a spring ring 102.
[0093] In this embodiment, power is supplied externally by the
piston rod 251 to the first coil end 103 of coil 90. The second
coil end 104 of the coil 90 leads to an annular sliding contact 105
which is clamped axially between the spacer disk 83 and the
insulating ring 84 and whose sliding arms 106, which project
outward approximately radially, contact the inner wall of the
grounding cylinder 248 so as to be pretensioned in a springing
manner.
[0094] In order to move the flap 3, the first drive devices is
controlled in such a way that the rotary drive 18 sets the threaded
spindle 29 in rotation, and the housing 7 and the protective tube
14 are moved relative to one another. At the same timer, the coil
90 of the second drive device 6 is energized so that the passage 80
in the piston 255 is released and the piston 255 can move in axial
direction. When the flap is stopped in a determined position, the
two drive devices 5 and 6 are turned off. The passage 80 in the
second drive device 6 is closed so that the piston 255 and the
piston rod 251 can no longer be moved. The second drive device 6
then holds the flap securely in the adjusted position.
[0095] Thus, while there have shown and described and pointed out
fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps that perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *