U.S. patent application number 10/266372 was filed with the patent office on 2003-05-08 for coupling assembly for agricultural implements.
Invention is credited to Lohmuller, Andreas, Sarfert, Andreas, Walter, Reinhold, Wilks, Eberhard.
Application Number | 20030087703 10/266372 |
Document ID | / |
Family ID | 7921417 |
Filed Date | 2003-05-08 |
United States Patent
Application |
20030087703 |
Kind Code |
A1 |
Lohmuller, Andreas ; et
al. |
May 8, 2003 |
Coupling assembly for agricultural implements
Abstract
A coupling assembly for agricultural implements has a friction
coupling (1), an electromagnet (6) and control mechanism (7). The
friction coupling (1) includes a friction assembly (4) which is
loaded by a pressure plate (14). The pressure plate (14) is loaded
by pressure springs (15, 16). The pressure plate (14) is adjustable
by an actuating device (5) which includes an electromagnet (6) and
an anchor plate (19). The control mechanism (7) includes a control
member (27) which, by changing the electric current, regulates the
pressure force of the pressure plate (14) during the coupling
and/or uncoupling operation. The housing (2) and the hub (3) are
associated with speed sensors (25, 26) which transmit a signal to
the control mechanism (7) to relieve the load on the friction
assembly. Thus, this prevents the friction coupling (1) from
overheating.
Inventors: |
Lohmuller, Andreas; (Bonn,
DE) ; Sarfert, Andreas; (Bonn, DE) ; Walter,
Reinhold; (Lohmar, DE) ; Wilks, Eberhard;
(Daufenbach, DE) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
7921417 |
Appl. No.: |
10/266372 |
Filed: |
October 8, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10266372 |
Oct 8, 2002 |
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09658098 |
Sep 8, 2000 |
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6497620 |
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Current U.S.
Class: |
464/29 ;
192/84.91; 464/2 |
Current CPC
Class: |
F16D 2500/5106 20130101;
B60W 2050/143 20130101; F16D 2500/3166 20130101; F16D 2500/111
20130101; F16D 2500/7101 20130101; F16D 2500/70418 20130101; F16D
48/066 20130101; F16D 48/064 20130101; F16D 2500/30426 20130101;
F16D 2500/30415 20130101; F16D 2500/1022 20130101; F16D 2500/30406
20130101; F16D 2500/1045 20130101; F16D 27/115 20130101 |
Class at
Publication: |
464/29 ; 464/2;
192/84.91 |
International
Class: |
F16D 003/10; H02N
013/00; F16D 027/00; F16D 037/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 1999 |
DE |
199 43 209.0 |
Claims
What is claimed is:
1. A coupling assembly for rotatingly driving agricultural
implements and for rotatingly driven drive portions in agricultural
implements, comprising: a friction coupling defining a longitudinal
axis, said coupling having a housing, a first friction face
positioned perpendicularly to the longitudinal axis; a hub received
in the housing, said hub being rotatable relative to said housing
around said longitudinal axis, said hub being axially displaceable
to a limited extent; at least one first hub plate firmly connected
to the hub, a pressure plate, pressure springs loading the pressure
plate, said pressure springs supported on a supporting plate
secured to the housing, friction plates being arranged between the
first friction face of the housing and the first hub plate, between
the first hub plate and the pressure plate and optionally between
each further plate connected to the housing and each further plate
connected to the hub; an actuating device including an annular
electromagnet arranged co-axially around a portion of the hub
projecting from the housing, said annular electromagnet being
rotatable relative to said hub and non-axially adjustably supported
along the longitudinal axis, said electromagnet securable against
rotation by a securing mechanism, said actuating device including
an anchor plate connected by setting pins to the pressure plate and
connected to the housing in a rotationally fast way; and control
mechanism for connecting the electromagnet to a power source.
2. A coupling assembly according to claim 1, wherein the supporting
plate includes apertures on its circumference, said apertures
extending parallel to the longitudinal axis and the setting pins
are guided through each aperture and between the pressure plate and
the supporting plate the pressure springs are received on the
setting pins.
3. A coupling assembly according to claim 1, wherein the
electromagnet is supported by a rolling contact bearing on the
portion of the hub projecting from the housing.
4. A coupling assembly according to claim 1, wherein the control
mechanism comprises a control member which, during start-up of the
friction coupling causes the actuating force generated by the
electromagnet and acting against the force of the pressure springs
to drop from a maximum to a reduced value over a predetermined time
period.
5. A coupling assembly according to claim 1, wherein a claw
coupling being connectable in series relative to the friction
coupling and the actuating device.
6. A coupling assembly according to claim 1, wherein the housing
and the hub are each associated with a speed sensor and said
control mechanism includes a comparator and a time member which, if
a predetermined speed differential between the housing and the hub
is exceeded, said control mechanism activates the electromagnet for
a predetermined time period to at least partially relieve the load
on the friction assembly.
7. A coupling assembly according to claim 1, wherein fixing
elements connecting the anchor plate to the supporting plate in a
limited axially displaceable and rotationally fast way.
8. A coupling assembly according to claim 1, further comprising a
second annular electromagnet arranged co-axially around the portion
of the hub projecting from the housing, said second annular
electromagnet being rotatable relative thereto and non-axially
adjustably supported along the longitudinal axis and said second
annular electromagnet securable against rotation by a securing
mechanism, said second annular electromagnet being activated in the
sense of increasing the pressure force on the friction
assembly.
9. A method of controlling a friction coupling including a housing,
a hub, a friction assembly loaded by a pressure plate, wherein the
pressure plate is loaded by pressure springs and, said friction
coupling being adjustable by an actuating device and a control
mechanism and adjustment by control means takes place in such a way
that, within a predetermined period of time, the pressure force of
the pressure plate, while starting from a minimum value, is
increased to the full value of pressure application.
10. A method according to claim 9, further comprising increasing
the pressure force for a pre-determined period of time.
11. A method according to claim 9, further comprising measuring the
speeds of the housing and hub and comparing said speeds to
determine if a predetermined speed differential is exceeded over a
predetermined time period, and if so relieving the load on the
friction assembly and generating a warning signal.
12. A method according to claim 9, wherein the minimum value of the
pressure force of the pressure plate is zero.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims priority to German
Patent Application 199 43 209.0 filed Sep. 9, 1999, which
application is herein expressly incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a coupling assembly for
agricultural implements which includes a friction coupling.
[0003] Friction couplings are used in agricultural machinery when
large masses, such as flywheels, need to be accelerated. During
acceleration, the coupling slips and transforms the absorbed energy
into heat. The friction coupling in such implements also reacts if
a blockage occurs inside the implement. Thus, the entire friction
power, or the driving power, is transformed into heat. The coupling
heats up very quickly. The stored heat can only be dissipated via
the coupling surface. In consequence, cooling takes a
correspondingly long time. Accordingly, a great risk of the
friction coupling overheating exists. This is the reason why
friction couplings are used only in those cases where large masses
need to be accelerated and where overloading due to blockages
occurs only occasionally.
SUMMARY OF THE INVENTION
[0004] It is an object of the invention to provide a coupling
assembly with a friction coupling where the risk of overheating is
reduced. In consequence, the coupling has a correspondingly longer
service life.
[0005] In accordance with the invention, a coupling assembly has a
friction coupling which defines a longitudinal axis. The friction
coupling has a housing with a first friction face positioned
perpendicularly to the longitudinal axis. A hub is received in the
housing. The hub is rotatable relative to the housing around the
longitudinal axis. The hub is axially displaceable to a limited
extent. The hub includes at least one first hub plate which is
firmly connected to the hub. A pressure plate, with pressure
springs, loading the pressure plate, is supported on a supporting
plate secured to the housing. Friction plates are arranged between
the first friction face of the housing and the first hub plate.
Also, friction plates are positioned between the first hub plate
and the pressure plate. Optionally, friction plates are positioned
between each further plate connected to the housing and each
further plate connected to the hub. An actuating device with an
annular electromagnet is arranged co-axially around a portion of
the hub projecting from the housing. The actuating device is
rotatable relative thereto and non-adjustably supported in the
direction of the longitudinal axis and securable against rotation
by securing means. The actuating device includes an anchor plate
which is connected by setting pins to the pressure plate. Also, the
actuating device is connected to the housing in a rotationally fast
way. A control mechanism is present to connect the electromagnet to
a power source.
[0006] An advantage of this assembly is that, during acceleration,
the transmitted torque slowly builds up to the nominal torque.
Thus, a high speed differential exists. The specific surface
pressure values at the beginning of the coupling process are low.
Accordingly, compared to conventional solutions, less heat is
generated which need to be absorbed by the coupling. Thus, the risk
of the coupling overheating is reduced and the service life is
increased.
[0007] A method of controlling a friction coupling exists to
achieve the objective. The friction coupling includes a housing, a
hub and a friction assembly loaded by a pressure plate. The
pressure plate is loaded by pressure springs. The pressure plate is
adjustable by an actuating device. Adjustment takes place by a
control mechanism such that, within a predetermined period of time,
the pressure force of the pressure plate, while starting from a
minimum value, is increased to the full value of pressure
application. The smallest possible minimum value is zero.
[0008] According to a further embodiment of the invention,
apertures extending parallel to the longitudinal axis are formed on
the circumference of the supporting plate. Setting pins are guided
through each of the apertures. In the region between the pressure
plate and the supporting plate, the pressure springs are received
on the setting pins. Accordingly, the anchor plate is guided by the
setting pins in an advantageous way. The electromagnet is
preferably supported by rolling contact bearings.
[0009] The control mechanism preferably includes a control member.
While the friction coupling starts to operate, the control member
causes the actuating force generated by the electromagnet, acting
against the force of the pressure springs, to drop from a maximum
to a reduced value over a predetermined period of time. When the
electromagnet no longer applies any force to the pressure plate in
the load-relieving sense, the coupling is set to the nominal
torque.
[0010] Additionally, a claw coupling is provided for applications
requiring the operation of uncoupling the driveline to proceed over
a long period of time. The claw coupling is connected in series
relative to the friction coupling and to the actuating device. The
claw coupling interrupts the flow of force in an energy-free way.
For a lengthy disconnecting operation, the power consumption of the
electromagnet would be too high.
[0011] The housing and the hub are each associated with a speed
sensor to prevent the friction coupling from overheating in the
case of overloading. The control mechanism includes a speed
comparator and a time member. If a predetermined speed differential
between the housing and the hub is exceeded, the control mechanism
activates the electromagnet for a predetermined period of time to
at least partially relieve the load on the friction assembly. A
warning signal indicates to the operator that overloading is taking
place. Thus, the signal enables the operator to stop the machine
and to remove any blockages which may have resulted in
overloading.
[0012] During activation of the electromagnet, to prevent the
anchor plate from hitting the electromagnet and to prevent the
setting pins from being bent at start up of the coupling, the
anchor plate is connected to the supporting plate by fixing
elements. Thus, the anchor plate is axially displaceable to a
limited extent and rotationally fast.
[0013] According to a further embodiment of the inventive method,
it is proposed to increase the pressure force for a predetermined
time period in order to act against a reduction in the friction
value when the coupling is used frequently. Also, the implement is
freed in the case of a blockage. Accordingly, a second
electromagnet or an additional coil are included to provide the
anchor plate with additional pressure.
[0014] Furthermore, to achieve disconnection in the event of
overloading, the speeds of the housing and of the hub are measured
and compared. If a predetermined speed differential is exceeded
over a predetermined period of time, the load on the friction
assembly is relieved and a warning signal is generated.
[0015] Accordingly, the coupling assembly and method of operation
with a controlled starting behavior enable the design of the
drivelines connected to and following the coupling assembly to take
place without taking into account the starting peaks. Even when the
coupling is warm, it is possible to provide compensation during the
starting process. Here, increased pressure is applied to the
friction coupling. As a result, the transmission of torque by the
coupling can be increased to such an extent that it corresponds to
the normal starting behavior of the coupling, beginning with the
cold condition.
[0016] From the following detailed description, taken in
conjunction with the drawings and subjoined claims, other objects
and advantages of the present invention will become apparent to
those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Two preferred embodiments of the invention are
diagrammatically illustrated in the drawing wherein:
[0018] FIG. 1 shows a first embodiment of a coupling assembly with
a friction coupling and an electromagnet in half a longitudinal
section, and
[0019] FIG. 2 shows a second embodiment wherein, in addition to the
friction coupling, a claw coupling is connected in series.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] FIG. 1 illustrates a friction coupling 1 which is actuated
electromagnetically. The coupling 1 includes a housing 2, a hub 3,
a friction assembly 4, an actuating device 5 with an electromagnet
6, and an anchor plate 19. The electromagnet 6 can be connected to
a power source 8 by a control mechanism 7.
[0021] The housing 2 is arranged and centered on a longitudinal
axis 9. The housing has a first friction face 10 arranged
perpendicularly relative to the longitudinal axis 9. A housing
plate 11 is connected to the housing 2. The housing plate 11 is
rotationally fast relative to the longitudinal axis 9 and is
axially adjustable along the longitudinal axis 9.
[0022] The hub 3 is received in the housing 2 and centered on the
longitudinal axis 9. The hub is rotatable relative to the housing 2
around the longitudinal axis 9. A first hub plate 12 is connected
to the hub 3. The first hub plate 12 is rotationally fast and
axially non-displaceable. A second hub plate 13 is connected to the
hub 3. The second hub plate 13 is rotationally fast relative to the
longitudinal axis 9 and axially displaceable along the longitudinal
axis 9.
[0023] A pressure plate 14 adjoins the first hub plate 12. The
pressure plate 14 is loaded by pressure springs 15, 16. The
pressure springs 15, 16 are supported on a supporting plate 17
connected to the housing 2. The supporting plate 17 is held by a
cylindrical sleeve in the open end of the housing. The sleeve is
held by, for example, portions pressed into circumferentially
extending openings in the housing 2. Setting pins 18 extend through
the centers of the springs 15, 16. Both the setting pins and
springs are arranged parallel to the longitudinal axis 9.
[0024] The setting pins 18 are axially fixed to the pressure plate
14. The setting pins 18 extend into apertures 20 in an annular
anchor plate 19. The setting pins 18 are fixed to the annular
anchor plate 19 by means of securing rings 31.
[0025] On its circumference, the supporting plate 17 includes
circumferentially spaced clearance apertures which extend parallel
to the longitudinal axis 9. The setting pins 18 extend through the
respective clearance apertures in the supporting plate 17.
[0026] Friction plates are positioned between the first friction
face 10 of the housing 2 and the second hub plate 13; between the
second hub plate 13 and the housing plate 11; between the housing
plate 11 and the first hub plate 12; and between the first hub
plate 12 and the pressure plate 14.
[0027] The anchor plate 19 adjoins the electromagnet 6. Fixing
elements 30 connect the anchor plate 19 to the supporting plate 17
of the housing 2 in an axially displaceable, to a limited extent,
and rotationally fast way. Even if wear occurs at the friction
plates 21, contact does not occur between the anchor plate 19 and
the electromagnet 6. Furthermore, the fixing elements 30 prevent
the setting pins 18 from being bent when the friction coupling 1
starts operating. The fixing element 30 shown in the drawing has
been displaced through 30.degree. about the axis 9 in order to
appear in the plane of the drawing.
[0028] The electromagnet 6 is annular in shape. The electromagnet 6
is arranged co-axially around a portion 22 of the hub 3 which
projects from the housing 2. The electromagnet 6 is rotatable
relative to the hub 3. The electromagnet 6 is supported by a
rolling contact bearing 23 and is non-axially adjustable along the
longitudinal axis 9. Securing mechanism 24 prevents the
electromagnet 6 from rotating when the friction coupling 1 starts
operating.
[0029] The hub 3 and the housing 2 are each associated with a speed
sensor 25, 26. The speed sensors 25, 26 measure the speed per unit
of time of the respective component. The first speed sensor 25, the
second speed sensor 26 and the electromagnet 6 are connected to the
control mechanism 7. The data measured by the speed sensors 25, 26
serve as input signals to control the electromagnet 6.
[0030] As a result of the controlling electromagnet 6, the torque
transmitted during acceleration of the driveline can slowly be
built up to the required nominal torque. If, at the start of the
coupling operation, a high speed differential exists between the
hub 3 and the housing 2, the specific surface pressure values
existing between the housing plate 11 and the hub plates 12, 13 and
the friction plates 21 can be minimized. As a result, the generated
heat, which needs to be absorbed by the friction coupling 1, can
also be minimized. The risk of overheating is reduced and the
service life of the friction coupling 1 is increased.
[0031] If a predetermined speed differential is exceeded between
the housing 2 and the hub 3 for a predetermined time period, the
speed sensors 25, 26 activate the electromagnet 6, via the control
mechanism 7, to relieve the load on the friction assembly 4. A
warning signal indicates to the operator that overloading has
occurred. Thus, the machine can be stopped and any blockages which
may have caused the overloading can be removed.
[0032] The control mechanism 7 includes a control member 27. The
control member 27, when the friction coupling 1 starts operating,
causes the actuating force generated by the electromagnet 6 and
acting against the force of the pressure springs 15, 16 to drop
from a maximum to zero during a predetermined period of time. If
the electromagnet 6 no longer applies a force to the pressure plate
14 in a load relieving sense, then the friction coupling 1 is set
to the required nominal torque.
[0033] In case the pressure plate 14 is to be additionally loaded,
a second electromagnet or an additional coil are provided. The
second electromagnet or coil are arranged co-axially relative to
the first electromagnet 6. It may be arranged to act on the anchor
plate 19 in the opposite sense to the electromagnet 6. As a result,
a brief increase in torque is achieved. A blocked implement can
thus be freed. Also, it is possible to compensate for a reduction
in torque which occurs when the friction coupling 1 is heated due
to a decreasing friction value between the housing plate 11 and the
hub plates 12, 13 and the friction plates 21.
[0034] FIG. 2 shows an embodiment where, in addition to the
friction coupling 1 with the control mechanism 7, a claw coupling
28 is provided. The claw coupling 28 is connected in series
relative to the friction coupling 1. A purely electromagnetically
actuated friction coupling 1, even when uncoupling the driveline,
requires electric current to the electromagnet 6. The claw coupling
28 achieves an energy-free interruption in the power flow if the
driveline has to be disconnected over a long period of time. The
claw coupling 28 is arranged and centered on the longitudinal axis
9. The claw coupling 28 includes a claw 29 which engages a
corresponding recess 32 in the hub 3 when the agricultural
implement is in operation. If disconnection is to take place, the
claw 29 of the claw coupling 28 is pulled out of the hub 3 by a
switching yoke. The switching yoke can be made to engage a
corresponding recess 33 of the claw coupling 28, so that the power
flow is interrupted.
[0035] While the above detailed description describes the preferred
embodiment of the present invention, the invention is susceptible
to modification, variation and alteration without deviating from
the scope and fair meaning of the subjoined claims.
* * * * *