This invention concerns an agricultural machine with
a height-adjustable working tool, in particular a
harvesting machine such as a combine harvester, with
15 a height-adjustable header.
DE 101 27 486 A1 refers to an agricultural machine
with an attachment that can be adjusted in height by
means of a lifting cylinder. The lifting cylinder is
20 connected to an inlet and outlet line through which
pressurized fluid can be fed into the lifting
cylinder to lift the attachment; to lower it,
pressurized fluid is discharged from the lifting
cylinder through the inlet and outlet lines. In order
25 to avoid pressure peaks in the lifting cylinder and
the inlet and outlet pipes when driving over uneven
floors, a pressure reservoir is connected to the
latter via a throttle point and a non-return valve.
When the pressure in the inlet and outlet lines
30 becomes high enough to open the check valve,
pressurized fluid can quickly flow from the lift
cylinder to the pressure reservoir; when the
pressure in the inlet and outlet lines subsequently
returns to a lower value than that in the pressure
2
reservoir, the pressurized fluid returns to the lift
cylinder via the throttle.
The above arrangement has no effect on the speed at
5 which the attachment can be raised and lowered. The
liftingspeed is determined by the performance of a
pump which feeds the pressure fluid into the inlet
and outlet pipes, the lowering speed by the flow
rate of a valve through which pressure fluid flows
10 from the inlet and outlet pipes to a tank in open
position. The heavier the attachment, the lower the
lifting speed in general, and the higher the lowering
speed. If the lowering speed is too high, there is
a risk of damage when the unit comes into contact
15 with the ground.
The task of the invention is to create a working
machine that allows the lowering speed to be easily
reduced without affecting the lifting speed.
20
The task is solved in an agricultural working machine
with a height-adjustable working tool, a source and
a depression for a pressurised fluid, an actuating
cylinder which, for vertical adjustment of the
25 working tool, can optionally be connected to the
source and the depression, a throttle point and a
non-return valve are connected in parallel to one
another by fluid technology to the actuating
cylinder on the one hand and to the source and the
30 depression on the other hand, and the throttle point
is formed by an internal passage of the non-return
valve.
3
The flow cross-section of the throttle body can be
dimensioned so that the desired maximum lowering
speed is not exceeded and damage during lowering can
be safely avoided; however, the flow rate from the
5 source to the actuator is not restricted as it can
largely pass through the non-return valve.
The check valve should be oriented to open when the
pressure on the source side is higher than the
10 pressure on the actuator side. For this purpose, the
non-return valve may comprise a source-side
connection, an actuator-side connection and a valve
body movable in a chamber which can be released from
a valve seat by a pressure at the source-side
15 connection which is higher than at the actuator-side
connection.
In order to keep the assembly of check valve and
throttle point compact, the passage is preferably
20 arranged in the check valve in such a way that it is
limited by the valve body on at least part of its
circumference. Such a passage, which is partly
limited by the valve body, can, for example, be
formed by a groove in the valve body or in the valve
25 seat.
In order to achieve a volume flow through the
throttle point that is as independent as possible of
coincidences in the positioning of the valve body at
30 the valve seat, the leak is preferably designed as
a bore crossing the valve body, i.e. delimited over
its entire circumference by the valve body.
4
In order to prevent the non-return valve from
blocking in the event that the valve body blocks the
actuator port when it is pressed by the flow of
pressure fluid against a wall of the chamber opposite
5 the valve seat, the valve body may have a radial
passage opening into the bore to allow pressure fluid
to flow from the chamber through the bore into the
actuator port.
10 To enable a sufficient volume flow of the pressure
fluid in such a situation, the bore should comprise
a narrow section facing the source-side connection
of the non-return valve and a wide section facing
the actuator-cylinder-side connection into which the
15 radial passage opens, in addition to a narrow section
acting as a throttling point.
Many check valves have a valve body spring loaded
against a valve seat to ensure safe closing when
20 pressure equilibrium exists between the valve ports.
In the present case, however, it is preferred that
the valve body is held by gravity in a closed
position at the valve seat in order to keep the
pressure drop at the non-return valve as low as
25 possible. However, in order to ensure safe closing,
the direction of movement of the valve body should
be as vertical as possible.
To ensure that the valve body safely reaches the
30 closed position, the valve body and seat may have
interacting conical sealing surfaces. The opening
angle of the conical sealing surfaces should not
exceed 60°.
5
A spring can be arranged between the valve body and
a wall on the actuator cylinder side of the chamber
to dampen the impact of the valve body against the
wall when the non-return valve is opened.
5
In order to prevent the spring from increasing the
pressure drop in the check valve at low flow rates,
it should be dimensioned so that the valve body can
be released from the valve seat without deforming
10 the spring, i.e. in the closed position of the check
valve there should be play either between the valve
body and the spring or between the spring and the
wall.
15 The invention is preferably applicable to a work
tool of high weight such as a header of a harvesting
machine, in particular a combine harvester.
Further characteristics and advantages of the
20 invention result from the following description of
execution examples with reference to the attached
figures. Show it:
Fig. 1 a side view of an invented combine
25 harvester;
Fig. 2 a top view of the combine harvester of
Fig. 1;
30 Fig. 3 a hydraulic diagram of the combine
harvester;
6
Fig. 4A valve block with a throttle point nonreturn valve assembly in an extended
representation;
5 Fig. 5An axial section through the throttle point
non-return valve assembly.
The combine harvester 1 shown in Fig. 1 and Fig. 2
carries in its front area a height-adjustable
10 cutting unit 2 for cutting grown crop. As the plan
view of Fig. 2 shows, the cutterbar 2 comprises a
transversely oriented auger 3 with two helices 4, 5
of different lengths, running in opposite
directions, which move the crop cut over the entire
15 width of the cutterbar 2 in a lateral direction in
front of the entrance of an inclined conveyor organ
6.
The laterally offset inclined conveyor 6, which
20 extends next to a driver's cab 7, feeds the crop to
a threshing separation rotor 8, which is located
behind and partly below the driver's cab 7 and, like
the worm 3, is oriented transversely to the direction
of travel of the combine 1. The crop fed from the
25 inclined conveyor 6 to a right end of the threshing
separation rotor 8 passes through the threshing
separation rotor 8 from right to left, and threshed
straw is ejected through an ejection opening at the
left end of the threshing separation rotor 8 into
30 the field.
Grain extracted during threshing and small fragments
of straw and fruit stalks such as ears or pods of
the crop emerge from the outer surface of the
7
threshing separation rotor 8 distributed over the
length of the threshing separation rotor 8 and reach
a base 9 extending under the threshing separation
rotor 8.
5
The composition of the material emerging from the
threshing separation rotor 8 varies over its length;
as the crop is depleted of grain on its way through
the threshing separation rotor 8, the proportion of
10 non-grain material in the emerging material stream
increases. Two augers 10, 11 are arranged on the
bottom 9 in order to shift the material lying on
them transversely in opposite directions and thus to
even out the concentration of the non-grain fraction
15 over the width of the bottom 9.
The material passes from floor 9 to a vibrating
moving preparation floor 12. Driven by the vibrating
movement, the material travels to the surface
20 grooved preparation floor 12 against its gradient to
the rear and finally falls over a trailing edge 13
of the preparation floor 12 onto a top sieve 14 of
a cleaning system. A blower 15 mounted under the
preparation tray 12 generates an air stream which
25 passes between the top sieve 14 and a bottom sieve
16 and between the bottom sieve 16 and a collecting
tray 17, entraining falling light non-grain
components. Thus, essentially free grain of
impurities enters a conveying channel 18 at the foot
30 of the collecting floor 17. A screw 19 rotating in
the conveying channel 18 clears the grain sideways
to an elevator 20, from which it is conveyed into a
grain tank 21 above the preparation floor.
8
Return material which is too coarse to pass through
sieves 14, 16 and too heavy to be carried away by
the air flow falls down at the rear edge of sieves
14, 16 and enters a second conveyor channel 22 in
5 which a screw 23 rotates. This auger 23 conveys the
return material to an elevator 24, which drops it to
the ground 9. There it is mixed by the screws 10, 11
under the material escaping from the Dresch
separating rotor 8 and again delivered to the
10 preparation floor 12.
On both sides of cutter deck 2 there are 25
positioning cylinders, which engage on the one hand
with the combine harvester chassis and on the other
15 hand with cutter deck 2, and which can be extended
and compressed to raise and lower cutter deck 2.
The hydraulic diagram of Fig. 3 shows an
unpressurised tank 26 acting as a sink for
20 pressurised fluid and a pump 27 acting as a source
of pressurised fluid by extracting it from tank 26
and pressing it into a pressure line 28.
The pressure line 28 is connected to a valve block
25 29, which houses several directional control valves
30 in a common housing. Each of the directional
control valves 30 has three primary ports 31, 32, 33
and three secondary ports 34, 35, 36 and can assume
three positions. In the switching state shown in
30 Fig. 3, all three directional control valves 30 are
in a neutral position, in which the ports 31, 34 of
each directional control valve 30 communicate with
each other and the three directional control valves
30 form a continuous connection from the pressure
9
line 29 via an inlet port 37 and an outlet port 38
of the valve block 29 to a pressureless line 39 and
the tank 26.
5 In the first active position of the directional
control valves 30, the connection between ports 31,
34 is interrupted and instead a connection between
ports 32, 36 is closed. As soon as one of the
directional control valves 30 assumes this first
10 active position, high pressure through ports 32, 36
reaches a controlled port 40 of the valve block 29.
In a second active position, the same controlled
port 40 is connected through ports 36, 34 to the
unpressurized line 39 and tank 26.
15
Fig. 4 shows the housing of the valve block 29.
Inlet, outlet and controlled connections 37, 38, 40
are each designed as bores with female thread. A
subassembly 41 is screwed into the controlled
20 connection 40, which supplies the positioning
cylinders 25, the internal structure of which is
shown in Fig. 5.
An axially symmetrical housing of subassembly 41
25 comprises two housing parts 42, 43 which are screwed
together in the axial direction and which together
delimit a chamber 44 and of which one has a port 45
screwed into port 40 and the other has a port 46
facing the positioning cylinders 25. A bore 47
30 extending from the lower port 45 along the axis
through the body portion 42 opens into chamber 44
via a tapered valve seat 48. The valve seat 48 is
opposed by an end wall 49 of the body portion 43,
10
from which a further axial bore 50 opens leading to
port 46.
A valve body 51 has a conical lower section 52, which
5 in the left section of Fig. 5 is close to the valve
seat 48. A cylindrical upper section 53 of the valve
body 51 has a slightly smaller diameter than an upper
side of the lower section 52. It is surrounded by a
coil spring 54 which is supported on the upper side.
10
A passage 55 extending along the axis through the
valve body 51 has a narrow portion 56 at the level
of the lower portion 52 and a wide portion 57 at the
level of the upper portion 53. A radial bore 58
15 crosses the upper portion 53. The diameter of the
bore 58 is at least twice that of the narrow portion
56.
When the directional control valve 30 is in the first
20 active position, high pressure is applied to port 45
and drives valve body 51 away from valve seat 48
toward the end wall 49 so that a passage 59 opens
between valve body 51 and valve seat 48 to pass
pressure fluid from port 45 into chamber 44. Before
25 the valve body 51 reaches the end wall 49, the coil
spring 54 strikes against it and prevents or delays
an impact of the valve body 51. Even if the flow of
the pressurized fluid is strong enough to press the
valve body 51 against the end wall 49, the bore 50
30 is not blocked because the pressurized fluid from
chamber 44 can reach the bore 50 via the radial bore
58 and the wide section 57. The pressure fluid can
therefore flow at a high flow rate to the positioning
11
cylinders 25 so that they can quickly lift the
cutting unit 2.
In the second active position of the directional
5 control valve 30, low pressure is applied to port
45, so that the valve body 51, driven first by the
coil spring 54, then only by its own weight, tends
again towards a sealing position at the valve seat
48. At the same time, when the actuators 25 carry
10 the weight of the cutterbar 2, there is high pressure
in chamber 44. When valve body 51 has reached valve
seat 48, pressurized fluid can only pass through
hole 55 from actuator 25 to tank 26. By selecting a
small enough diameter of the narrow section 56, the
15 speed at which the cutter 2 lowers in the second
active position of the directional control valve 29
can be made as small as desired, so that a smooth
lowering of the cutter 2 can be ensured even with
high weight.
20
12

reference signs
5
1 combine harvester
2 cutting unit
3 snail
4 spiral
10 5 spiral
6 Inclined conveyor organ
7 driver's cockpit
8 Threshing separation rotor
9 ground
15 10 snail
11 snail
12 preparation floor
13 trailing edge
14 top sieve
20 15 blower
16 bottom sieve
17 collecting tray
18 conveyor channel
19 snail
25 20 elevator
21 grain tank
22 conveyor channel
23 snail
24 elevator
30 25 support cylinder
26 tank
27 pump
28 pressure pipe
29 valve block
13
30 directional valve
31 primary connection
32 primary connection
33 primary connection
5 34 secondary connection
35 secondary connection
36 secondary connection
37 inlet port
38 outlet connection
10 39 unpressurized line
40 controlled connection
41 assembly
42 (lower) housing part
43 (upper) housing part
15 44 chamber
45 (lower) connection
46 (upper) connection
47 bore
48 valve seat
20 49 bulkhead
50 bore
51 valve body
52 lower section
53 upper range
25 54 coil spring
55 passage
56 narrow section
57 wide section
58 bore
30 59 passage

14
1. Agricultural machine (1) having a height5 adjustable working tool (2), a source (27)
and a depression (26) for a pressurized
fluid, an actuating cylinder (25) which can
be connected selectively to the source (27)
and the depression (26) for vertical
10 adjustment of the working tool (2), a
throttle point and a non-return valve, which
are connected to the actuating cylinder (25)
on the one hand by fluid technology parallel
to one another, characterized in that the
15 throttle point and the non-return valve on
the other hand are connected to the source
(27) and the sink (26), and the throttle
point is formed by an internal passage (55)
of the non-return valve.
20
2. Agricultural working machine according to
Claim 1, characterized in that the non-return
valve comprises a connection (45) on the
source side, a connection (46) on the
25 actuating cylinder side and a valve body (51)
which can move in a chamber (43) and can be
released from a valve seat (48) by a pressure
at the connection (45) on the source side
which is higher than at the connection (46)
30 on the actuating cylinder side.
3. Agricultural working machine according to
claim 2, characterized in that the passage
(55) is delimited by the valve body (51).

WE CLAIM:

4. Agricultural working machine according to
claim 2 or 3, characterized in that the
passage (55) is designed as an axial passage
5 crossing the valve body (51).
5. Agricultural working machine according to
Claim 4, characterized in that the valve body
(51) has a radial bore (58) which opens into
10 the passage (55).
6. Agricultural working machine according to
Claim 5, characterized in that the passage
(55) comprises a narrow section (56) facing
15 the source-side connection (45) of the nonreturn valve and a wide section (57) facing
the actuator-cylinder-side connection (46),
and the radial bore (58) opens into the wide
section (57).
20
7. Agricultural working machine according to one
of claims 2 to 6, characterized in that a
spring (54) is arranged between the valve
body (51) and a wall (49) of the chamber (44)
25 on the actuating cylinder side, in order to
dampen a striking of the valve body (51)
against the wall (49).
8. Agricultural working machine according to
30 claim 7, characterized in that the valve body
(51) can be released from the valve seat (48)
without deforming the spring (54).
9. Agricultural working machine according to one
35 of claims 2 to 8, characterized in that the
16
valve body (51) and the valve seat (48) have
cooperating conical sealing surfaces.
10. Agricultural working machine according to one
5 of the preceding claims, characterized in
that it comprises a valve block (29) in which
a plurality of directional valves (30) are
grouped together in a common housing and are
connected via a first connection (37) to the
10 source (27) and a second connection (38) to
the sink (26), and in that the non-return
valve is inserted, in particular screwed,
into a third connection (40) of the housing
which is associated with at least one of the
15 directional valves (30).
11. Agricultural working machine according to one
of the preceding claims, characterized in
that it is a harvesting machine, in
20 particular a combine harvester (1), and the
working tool is a harvesting attachment (2).