U.S. patent application number 10/290350 was filed with the patent office on 2003-05-15 for device and method for wrapping bodies, in particular bales of harvested material.
This patent application is currently assigned to Lely Enterprises. A.G., a Swiss Limited Liability Company. Invention is credited to Platon, Gunter.
Application Number | 20030089081 10/290350 |
Document ID | / |
Family ID | 8181198 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030089081 |
Kind Code |
A1 |
Platon, Gunter |
May 15, 2003 |
Device and method for wrapping bodies, in particular bales of
harvested material
Abstract
The invention relates to a device for wrapping bodies, in
particular harvested material bales (1, 34, 50, 65) of hay, straw
or wilted green crop, which are wrapped in at least one wrapping
material web (8, 36, 57, 74). In order to improve and simplify this
device with regard to adjustment and monitoring of the wrapping
process, it is proposed according to the invention that the device
(3, 4, 44, 49, 64) comprise one or more sensor means (23, 24, 28,
30, 42, 43, 47, 59, 63, 71, 75, 76) for monitoring and/or
controlling the wrapping process and/or checking the finished bale
wrapping.
Inventors: |
Platon, Gunter; (Klein
Denkte, DE) |
Correspondence
Address: |
Penrose Lucas Albright Esq.,
MASON, MASON & ALBRIGHT
P.O. Box 2246
Arlington
VA
22202-0246
US
|
Assignee: |
Lely Enterprises. A.G., a Swiss
Limited Liability Company
|
Family ID: |
8181198 |
Appl. No.: |
10/290350 |
Filed: |
November 8, 2002 |
Current U.S.
Class: |
53/399 ; 53/211;
53/587; 53/588; 53/64 |
Current CPC
Class: |
A01F 15/071 20130101;
A01F 2015/076 20130101; A01F 2015/073 20130101; A01F 2015/0755
20130101; A01F 2015/0725 20130101 |
Class at
Publication: |
53/399 ; 53/587;
53/588; 53/211; 53/64 |
International
Class: |
B65B 011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 9, 2001 |
EP |
0 1204262.8 |
Claims
1. A device for wrapping bodies, in particular harvested material
bales (1, 34, 50, 65) of hay, straw or wilted green crop, which are
wound in at least one wrapping material web (8, 36, 57, 74),
characterised by one or more sensor means (23, 24, 28, 30, 42, 43,
47, 59, 63, 71, 75, 76) for monitoring and/or controlling the
wrapping process and/or for checking the finished bale
wrapping.
2. A device according to claim 1, characterised by one or more
sensor means (24, 42, 43, 63, 71, 75) for monitoring and/or
controlling the correct overlap of two wrapping material plies (19,
20, 57, 61, 77, 74).
3. A device according to claim 1 or claim 2, characterised in that
at least one sensor means (24, 63, 71, 75) is arranged between the
wrapping material web (20, 57, 74) coming from a wrapping material
supply roll (5, 58, 73) and/or the previous wrapping material web
(19, 61, 67) located on the bale (1, 50, 65).
4. A device according to one of claims 1 to 3, characterised by one
or more sensor means (23, 28, 30, 42, 43, 47, 59, 76) for
monitoring and/or controlling the complete, presettable wrapping of
the bale (1, 34, 50, 65) of harvested material.
5. A device according to claim 1 or claim 4, characterised in that
at least one sensor means (28, 30, 59, 76) is associated with the
unwrapped bale side (27, 31, 62), being offset circumferentially by
a small distance contrary to the direction of rotation (10, 32, 56,
72) of the bale (1, 34, 50, 65) relative to the wrapping material
web (20, 36, 57, 74) coming from a wrapping material supply roll
(5, 35, 58, 73), which sensor means (28, 30, 59, 76) detects that
the bale (1, 34, 50, 65) is covered with wrapping material.
6. A device according to one of claims 1 to 5, characterized in
that one or more sensor means (59, 63, 71, 75, 76) is/are arranged
on a wrapping table (49, 64), which turns the bale (50, 65) during
wrapping operation about both a horizontal (33, 55) and a vertical
axis (51, 66).
7. A device according to claims 1 to 6, characterized in that at
least one sensor means (24) is arranged on one or more rotary arms
(3) circling round the bale (1) during wrapping operation.
8. A device according to one or more of the preceding claims,
characterised by an electronic open-/closed-loop control unit (22),
which comprises at least one sensor means (23, 47) for detecting
and/or displaying the number of wrapping material windings on the
bale (1, 34).
9. A device according to claim 8, characterised in that the number
of wrapping material windings may be detected up to the first
complete wrapping of the entire bale surface as a function of the
sensor means (28, 30, 59, 76).
10. A device according to claim 9, characterised in that the number
of wrapping material windings may be stored up to the first
complete wrapping of a bale (1, 34, 50, 65) in a memory unit of the
electronic open-/closed-loop control unit (22).
11. A device according to one of preceding claims 8 to 10,
characterised in that the electronic open-/closed-loop control unit
(22) comprises an input unit (21), into which the desired number of
wrapping material plies or layers may be input.
12. A device according to one or more of the preceding claims,
characterised in that the electronic open-/closed-loop control unit
(22) comprises a computer which, as a function of the detected
and/or preset values, itself determines the number of wrapping
material windings, i.e. the number of bale revolutions about the
axis (51, 66) or the number of rotary arm revolutions (3, 44),
required for the preset number of wrapping material plies to be
reached.
13. A device according to claim 12, characterised in that the
number of wrapping material windings is determined taking into
account a safety factor which may be preset in an input unit
(21).
14. A device according to one or more of preceding claims 8 to 11,
characterised in that the electronic open-/closed-loop control unit
(22) comprises an input unit (21), into which the degree of overlap
(18, X, Y) of two successive wrapping material windings (19, 20,
57, 61, 67, 70) may be directly or indirectly input.
15. A device according to one or more of the preceding claims,
characterised in that the actual degree of overlap may be directly
or indirectly influenced in the event of deviation from the desired
degree of overlap as a function of the sensor means (24, 42, 43,
63, 71, 75).
16. A device according to claim 15, characterised in that the
sensor means (24, 42, 43, 63, 71, 75) at least signals to the
operator deviations from the desired degree of overlap.
17. A device according to one or more of the preceding claims,
characterised in that a gloss sensor is provided, which detects the
unwrapped bale surface as matt and the wrapped bale surface as
glossy.
18. A device according to one or more of preceding claims 1 to 16,
characterised in that a conductivity sensor is provided, which
responds to the different conductivities of a bale (1) with and
without a wrapping of wrapping material (2).
19. A device according to one or more of preceding claims 1 to 16,
characterised in that the device comprises a pressure sensor, which
detects the different measured feed pressure values of a bale
surface with and without wrapping material.
20. A device according to one or more of the preceding claims,
characterised in that a sensor means (24, 42, 63) responds to
different wrapping material thicknesses through overlapping
wrapping material webs.
21. A device according to one or more of the preceding claims,
characterised in that a sensor means (24, 42, 63, 71) detects
different wrapping material colours or coloured markings.
22. A device according to one or more of the preceding claims,
characterised in that a sensor means (24, 29, 42, 59, 63, 71, 76)
responds to different light or sound reflections from the wrapped
and unwrapped bale surface.
23. A device according to one or more of the preceding claims,
characterised in that one or more sensor means may be conformed to
different bale dimensions and/or wrapping material widths.
24. A device according to one or more of the preceding claims,
characterised in that the sensor means (24, 63, 71, 75) may be
adjusted to preset overlaps (18, X, Y) of two wrapping material
webs (19, 20, 57, 61, 67, 70).
25. A device according to one or more of the preceding claims,
characterised in that a sensor means (24, 29, 42, 59, 63, 71, 75,
76) is arranged at a distance from the bale surface.
26. A device according to one or more of the preceding claims,
characterised in that the sensor means (30, 42, 43) is carried by a
guide element (41) following the bale contour.
27. A device according to one or more of the preceding claims,
characterised in that a sensor means (41, 42, 43) directly or
indirectly measures and/or signals the feed path of the bale (34)
in the circumferential direction of rotation (32) of the bale
(34).
28. A device according to one or more of the preceding claims,
characterised in that a sensor (42, 43) is provided for
establishing whether the bale (34) turns during wrapping
operation.
29. A device according to claim 28, characterised in that the
sensor (42, 43) is in direct or indirect active connection with at
least one further sensor means (47) and the open-/closed-loop
control unit (22)
30. A device according to one or more of the preceding claims,
characterised by a film tear display means and/or a means for
signalling the end of the wrapping material supply roll.
31. A device according to one or more of claims 28 to 30,
characterised in that the sensor (42, 43) is coupled to the
electronic open-/closed-loop control unit (22) and in that the
wrapping process may be influenced directly or indirectly by the
sensor (42, 43).
32. A device according to one or more of the preceding claims,
characterised in that a length meter for the length of wrapping
material applied to a bale, i.e. drawn off from the wrapping
material supply roll is associated with a wrapping material web, a
wrapping material web supply roll or at least one deflection or
take-off roll, which length meter signals and/or displays the
measured value.
33. A device according to one or more of the preceding claims,
characterised in that one or more sensor means signal if, within a
presettable time, a presettable bale rotation or a predeterminable
take-off length of the wrapping material, the working area of at
least one sensor means is not covered.
34. A method of wrapping bodies in a device according to one or
more of the preceding claims, characterised in that the number of
wrapping material windings required to wrap the bale (1, 34, 50,
65) completely for the first time is measured by sensor means (28,
23, 30, 47, 59, 76) and signalled to an open-/closed-loop control
unit (22) and/or the operator.
35. A method of wrapping bodies according to claim 34,
characterised in that the measured number of wrapping material
windings serves as a parameter for the wrapping material plies or
layers to be applied to the bale.
36. A method according to claim 35, characterised in that the
open-/closed-loop control unit (22) comprises a computer which
calculates the total number of wrapping material windings from the
measured number of wrapping material windings and the preset number
of wrapping material plies/layers.
37. A method according to claim 35 or claim 36, characterised in
that a safety parameter may be input directly or indirectly into
the open-/closed-loop control unit (22), which safety parameter
adds one or more wrapping material windings to the measured number
of wrapping material windings.
38. A method of wrapping bodies according to one of claims 34 to 37
or in a device according to one of the preceding claims,
characterised in that the desired degree of overlap (18, X, Y) of
two successive wrapping material webs or the speed ratio may be
input directly or indirectly into an electronic open-/closed-loop
control unit (22).
39. A method according to claim 38, characterised in that deviation
of the actual degree of overlap of two successive wrapping material
webs (19, 20, 57, 61, 67, 74) on the bale (1, 34, 50, 65) from the
preset desired degree of overlap (18, X, Y) may be established by
one or more sensor means (23, 24, 42, 43, 63, 71, 75) and signalled
to the open-/closed-loop control unit (22) and/or the operator.
40. A method according to claim 39, characterised in that the
actual degree of overlap may be influenced as a function of the
sensor means (24, 42, 43, 63, 71, 75) in particular in the event of
deviation of the actual degree of overlap from the desired degree
of overlap.
41. A method according to claim 38, characterised in that the
wrapping material web width may be input into an electronic
open-/closed-loop control unit (22).
42. A method according to claim 41, characterised in that the
degree of overlap may be influenced as a function of the wrapping
material width.
Description
[0001] The invention relates to a device for wrapping bodies, in
particular harvested material bales of hay, straw or wilted green
crop, which are wound in at least one wrapping material web.
[0002] The invention further relates to a method for wrapping
bodies, in particular harvested material bales of hay, straw or
wilted green crop using an above-mentioned device.
[0003] The wrapping of bales of fresh or wilted grass with a
stretchy, self-adhesive film is currently becoming ever more
popular, because, in addition to other advantages, the tightly
wrapped bales ripen into silage inside the film wrapping in a
relatively short time, without environmentally harmful silage juice
escaping, as is the case with silage clamps or tower silos.
[0004] Both round and square bales are wrapped. At present, there
are essentially two bale wrapping systems which are used in
practice. In the case of the "wrapping table system", successive
overlapping film wrappings are wound two to three times around the
entire outer bale circumference during rotation of the bale about a
horizontal axis and simultaneous rotation about a vertical axis. In
the case of the "rotary arm apparatus", although the bale again
lies on a type of wrapping table, which turns the bale about its
horizontal longitudinal axis, the wrapping table does not turn
simultaneously about its vertical axis but instead the relative
rotation between bale and supply roll is produced by a rotary arm
circling around the bale and carrying the film roll at its outer
end.
[0005] In addition to the bale quality, the silage quality depends
in particular on the quality of the film wrapping.
[0006] The quality of the film wrapping is determined by the
quality of the film, i.e. the production method (drawn or blown),
film thickness, film colour (white, black, green), tear strength,
tackiness and gas permeability, and in particular by the care taken
by the user, i.e. precise adjustment of film prestretching, uniform
and sufficient film overlap and the correct number of plies of film
webs or layers.
[0007] At present, these adjustments are performed manually, such
that whether or not high-grade silage is obtained depends on the
amount of care taken by the operator.
[0008] The following parameters need to be taken into consideration
during adjustment:
[0009] film width
[0010] bale diameter
[0011] number of film plies
[0012] number of wrappings
[0013] film web overlap
[0014] number of film webs or film supply rolls per bale
revolution
[0015] In the case of the rotary arm apparatus, adjustment is
performed as follows:
[0016] Preset values:
[0017] bale diameter 1.2 m
[0018] film width: 500 mm
[0019] degree of overlap 55%
[0020] 4 film plies
[0021] The degree of overlap may be preset at the apparatus, e.g.
by specifying the rotational speed ratio of bale to rotary arm.
When wrapping is begun, the preset film overlap of the first film
plies is checked visually and corrected manually.
[0022] The necessary number of rotary arm revolutions depends on
the number of film plies and the bale diameter. Initially, during
wrapping of the first bale, the number of revolutions of the rotary
arm is counted which is necessary for the entire surface to be
wrapped in film. This number of revolutions is also shown on the
display of the electronic control apparatus. If film overlap is set
at 55%, two film plies/layers have now been laid on the bale. The
bale has turned half a revolution about its cylinder axis. If 4
film plies are desired, the counted value is multiplied by 2 (4
plies) or by 3 (6 plies) and this value is input into the
electronic control unit, such that succeeding bales are
automatically wrapped according to these stored preset values.
[0023] These adjustments are particularly disadvantageous to
perform in the case of the round baler/downstream wrapper
combinations which have come increasingly onto the market recently,
since the wrapper is not visible from the tractor seat.
[0024] In addition to operator effort, this procedure has the
following disadvantages:
[0025] no overlap monitoring
[0026] no monitoring that the preset number of film wrappings
produces the preset number of plies over the entire bale
surface
[0027] predetermined settings apply only to
[0028] a) one bale diameter
[0029] b) one film width
[0030] c) one film web per bale revolution
[0031] d) one degree of overlap
[0032] As soon as at least one of the parameters a to d changes,
the bale is no longer wrapped as set. If, for example, a bale
diameter of 1.3 m is wrapped instead of a 1.2 m bale diameter, film
wrappings are lacking over part of the circumference.
[0033] The object of the invention is to improve and simplify the
above-described device with regard to adjustment and monitoring of
the wrapping process.
[0034] This object is achieved with regard to the device by one or
more sensor means for monitoring and/or controlling the wrapping
process and/or checking of the finished bale wrapping.
[0035] The object of the invention is achieved with regard to the
method in that the number of wrapping material windings required to
wrap the bale completely for the first time is measured by sensor
means and signalled to an open-/closed-loop control unit and/or the
operator.
[0036] The device and/or method according to the invention thus
allow completely novel operation and monitoring, wherein
adjustments and monitoring proceed automatically and preset values
are reduced to a minimum. It is necessary merely to preset the
number of plies of wrapping material. In the case of predetermined
wrapping material width and preset wrapping material overlap, the
correct number of wrapping material windings per bale to achieve
the preset wrapping material plies is determined in each case by
means of a first sensor means as a function of different bale
diameters, wrapping material overlap and/or one or more wrapping
means and in particular automatically and independently of the
operator and used to control the device.
[0037] During the wrapping process, a second sensor means tests
once, repeatedly or constantly the actual overlap of two successive
wrapping material windings. The signals from one or both sensor
means are forwarded to an alarm or information means for the
operator and/or to an open-loop and/or closed-loop control means
for the wrapping process, which analyses the values, performs a
desired/actual value comparison and converts them into control
variables for adjusting the actual values to the desired values.
This automatic control and monitoring of the wrapping process is of
particular advantage in the case of wrapping devices which are
arranged behind the baler.
[0038] A simplified embodiment consists in checking or additionally
post-checking the finished bale wrapping by means of sensor
means.
[0039] Further expedient developments of the invention are revealed
by the remaining subclaims and by the following description of a
plurality of exemplary embodiments of the subject matter of the
invention made with reference to the drawings, in which:
[0040] FIG. 1 is a perspective, schematic representation of a
rotary arm wrapping device according to the invention with a sensor
means associated with an unwrapped, dotted round bale area and a
sensor means associated with the wrapped round bale area and
arranged on a rotary arm,
[0041] FIG. 2 is a view according to FIG. 1 with a sensor means
associated with an unwrapped circumferential area of a round bale
and a sensor means for detecting when the bale is at a standstill,
wherein the electronic and hydraulic control elements are omitted
for the sake of clarity,
[0042] FIG. 3 is a perspective, schematic representation of a
rotary table wrapping device according to the invention with a
sensor means associated with an unwrapped bale area and a sensor
means associated with a wrapped bale area, and
[0043] FIG. 4 is a schematic side view of a rotary table wrapping
device with two sensor means in a different arrangement.
[0044] The device illustrated in FIG. 1 for wrapping a bale 1 of
harvested material with a stretchy and self-adhesive film 2 is an
exemplary embodiment with a rotary arm 3 and a stationary wrapping
table 4 for accommodating a bale 1 of harvested material, as
described substantially in EP 0 234 763 A1. The rotary arm 3
carries at its outer, lower end a film supply roll 5, which is
passed during the wrapping process around the bale 1 of harvested
material in a rotary motion about a vertical axis 7 in a direction
of rotation 6, wherein a strip of film 8 is drawn off from the film
supply roll 5 and wrapped about the bale 1 of harvested material
rotating in a direction of rotation 10 about a horizontal axis of
rotation 9. Instead of film, a different wrapping material may also
be used, such as netting for example. As is clear from FIG. 1, the
entire outer bale circumference has been wound round with
overlapping strips of film, for example twice, such that the
wrapping process is shown directly before completion, which is
achieved in that a cutting/clamping means, not shown, severs the
film portion 8 in the free area between bale 1 and rotary arm 3 and
holds it ready by clamping for wrapping a further bale 1.
[0045] As is additionally clear from FIG. 1, a film stretching
device 11 is fitted in the movement path of the film strip 8
between the film supply roll 5 and the bale 1 of harvested
material, which stretching device 11 comprises at least two
vertically disposed stretching rollers 12. The film stretching
device 11 is combined into a structural unit with the supply roll 5
and fitted to the rotary arm 1 as such.
[0046] A rotary drive is provided for the round bale. This consists
of a hydraulic motor 13, indicated only schematically, which drives
one or both rollers 14. A further rotary drive, which likewise
consists of a hydraulic motor 15, is provided for the rotary arm 3.
Both hydraulic motors 13, 15 are connected via fluid lines to
hydraulic valves 16, 17 and are subject to open- or closed-loop
control, which controls by the open- or closed-loop system the
speed of revolution of the bale 1 relative to the speed of
revolution of the rotary arm 3 to produce a uniform, presettable
wrapping pattern on the bale 1. This open- or closed-loop control
proceeds in such a way that, by selecting the speed ratio of bale 1
to rotary arm 3, an overlap distance 18 is predetermined between
two film webs 19, 20 which is intended to remain constant during
the entire wrapping process.
[0047] The open- or closed-loop control system illustrated in the
drawing is an exemplary embodiment of the invention. This consists
substantially of an operating device 21 arranged in a tractor cab,
which device 21 is in active connection with an open- or
closed-loop control unit 22. In addition to the hydraulic motors
13, 15, a plurality of sensor means are connected to the open- or
closed-loop control unit 22 as actuators:
[0048] A first sensor means 23 detects the actual speed of the
rotary arm 3. A second sensor means 24 is arranged on the rotary
arm 3 and measures during the wrapping process the overlap distance
18 between the film web 20 coming from the film stretching device
11 and the previous film web 19 located on the bale 1 or checks
compliance with a predetermined overlap distance. The sensor means
24 is arranged between film web 20 and film supply roll 5 at a
level within the film width which corresponds to the preset overlap
distance and is so aligned in the initial and final position 25 of
the rotary arm 3 illustrated in FIG. 1 that the area 26 of the
previous film web 19 which is lower in the direction of rotation 10
of the bale 1 lies in the response zone of the sensor means 24,
i.e. in the event of proper bale wrapping the sensor means 24
detects film constantly but immediately detects an unwrapped area
27 if the overlap distance 18 is exceeded. This signal is
transmitted to the operator and/or the open-/closed-loop control
unit 21, 22, which adjusts to the desired overlap as quickly as
possible.
[0049] By arranging a plurality of sensors 24 at a distance above
one another, the degree of deviation of the actual overlap from the
desired overlap could also be measured and signalled. Since, for
example, 750 mm wide films are processed with a different degree of
overlap (70%), the sensor means 24 is height-adjustable within the
appropriate range. An undesirable 100% film overlap may be
prevented for example with a bale standstill sensor 42, shown and
explained in FIG. 2, which automatically interrupts or corrects the
wrapping process if the bale comes to a standstill or signals the
bale standstill to the operator. The basic setting of the bale 1 to
rotary arm 3 speed ratio, which determines the degree of overlap,
is performed in known manner by electronic or manual actuation of
the hydraulic valve 17 of the hydraulic motors 13, 15 connected in
series. According to the invention, control of the hydraulic valve
17 is performed by the sensor means 24 using film overlap as the
controlled variable. However, it is in principle also possible to
combine film overlap as a controlled variable with a drive system
in which feed of the bale 1 is measured in the
circumferential/rotational direction 10 per unit time and this
controlled variable is applied to control of the rotary drive 15 of
the rotary arm 3.
[0050] A third sensor means 28 is provided, to establish how many
rotary arm revolutions are necessary to achieve a first complete
wrapping of the entire bale 1. The sensor means 28 is associated
with the unwrapped bale area 27 shown as a dotted zone, which area
27 is last to be wound in a film web. This is achieved in that the
sensor means 28 is arranged on the unwrapped bale end 29, being
offset circumferentially by a small distance contrary to the
direction of rotation 10 of the bale 1 relative to the film portion
20 applied to the bale 1 and drawn off from the film supply roll 5.
Since the bale 1 is driven at its circumference, the feed path of a
bale 1 is the same, be the diameter small or large. A larger bale
diameter merely requires a larger number of windings. This sensor
means 28 allows the establishment of the in each case correct
number of rotary arm revolutions not only in the case of different
bale diameters but also in the case of devices with two or more
film webs 8 per revolution of the rotary arm 3 or different film
widths as a prerequisite for automatic running of the wrapping
process in the event of varying parameters. For adaptation to
different bale dimensions, the sensor means 28 is adjustable.
[0051] The mode of operation of the device according to the
invention is as follows:
[0052] The following preset values are input into the operating
device 21, for example:
[0053] film overlap: 60%
[0054] number of wrapping plies: 4
[0055] safety wrapping (additional rotary arm revolution): 1
[0056] The bale 1 rotates during the wrapping operation in the
direction of arrow 10. At the same time, the rotary arm 3 circles
round the bale 1 with the film supply roll 5 in the direction of
the arrow 6, wherein a film web 20 is drawn off from the supply
roll 5 and laid on the unwrapped bale surface so as partially to
overlap the previous film web 19. The rotary arm position 25
illustrated in FIG. 1 corresponds to an initial or final position
after one complete revolution of the rotary arm 3. The sensor means
24 attached to the rotary arm 3 is directed in this rotary arm
position 25 towards the lower film area of the previous film web
19, the lower edge 26 of which is shown by dash-dotted lines. As
soon as the overlap of the two film webs 19, 20 becomes smaller
during a rotary arm rotation than preset, the open-/closed-loop
control unit 22 receives a signal, whereupon the bale 1 to rotary
arm 3 speed ratio is so changed by actuating the electronically
actuatable power control valve 17 that the sensor 24 again lies in
the film area 26. The bale 1 illustrated in FIG. 1 has already been
wrapped in film as far as the dotted area 27. The first sensor
means 23 has measured the rotary arm revolutions up to the wrapping
state illustrated and stored them in the memory unit. On the next
revolution of the rotary arm 3, the dotted area 27 is covered with
film. This is recognised and signalled to the open-/closed-loop
control unit 22 by the sensor means 28. There are now two
plies/film layers everywhere on the bale 1, which bale 1 has turned
a half revolution about its own axis 9. The computer now adds the
number of predetermined safety windings to the measured number of
rotary arm revolutions and multiplies this number by the factor two
and allows the rotary arm 3 to run on automatically until the
complete, determined number of rotary arm revolutions has been
achieved. Upon completion of the wrapping process, the bale
comprises 4 film plies or layers. If the bale diameter now changes
or a 750 mm wide film is used instead of a 500 mm wide film, the
open-/closed-loop control unit 22 calculates in each case
automatically the correct number of rotary arm revolutions to apply
4 plies of film to the bale 1 by means of the number of rotary arm
revolutions measured by the sensor means 23 as a function of the
sensor means 28. The operator does not have to effect any
manipulations. As early as during the first full rotary arm
revolution and then during further revolutions, the second sensor
means 24 monitors the preset overlap 18 of the film webs 19, 20 and
signals deviations, which are immediately adjusted automatically by
the open-/closed-loop control unit 22. Thus, proper control and
monitoring of the wrapping process is ensured without visual
monitoring by the operator. A bale standstill or a feed path of the
bale 1 in the direction of circumferential rotation 10 of the bale
1 which deviates substantially from the preset degree of film
overlap may be signalled by the sensor means 42 illustrated in FIG.
2 and taken into account during control. Tears in the film or the
end of a film supply roll is signalled by known means, which
influence control accordingly. It is also possible, in the context
of quality control, to check or post-check the finished bale
wrapping during a bale revolution.
[0057] The exemplary embodiment according to FIG. 2 shows a sensor
means 30 for detecting the last wound bale area 31, which is shown
as a dotted area. In this Example, the sensor means 30 is
associated with the unwrapped circumferential bale side and is
offset by a small distance contrary to the direction of rotation 32
of the harvested material bale 34 rotating about its cylinder axis
33 during the wrapping process relative to the film web 36 drawn
off the film supply roll 35. The sensor means 34 is arranged on a
pivoted lever 37, which is mounted fixedly but rotatably on the
frame 38 and is drawn by a spring 39 against a limit stop 40. The
pivoted lever 37 comprises a tracer roll 41, which runs over the
bale surface such that the sensor means 30 is held at a constant
distance from the bale surface during bale rotation about its axis
33. The tracer roll 41 simultaneously takes the form of a sensor
means 42 to sense when the bale is at a standstill and of a feed
meter for the bale 34. To this end, the tracer roll 41 is provided
with a plurality of pulse generators 43 distributed about the
circumference. If the pulses are absent during rotation of the
rotary arm 44 about the axis 45 in the direction of the arrow 46,
this is signalled by the sensor means 42 of an open-/or closed-loop
control unit, not shown, which influences control accordingly.
Furthermore, the control unit counts the pulses of the tracer wheel
41 in each case during one revolution of the rotary arm 44 about
the vertical axis 45. The revolutions of the rotary arm 44 are
detected by a third sensor means 47. In this way, the actual film
overlap may be checked via the feed measurement; this overlap must
not be greater during one rotary arm revolution than the overlap
distance 18 between two overlapping film webs 19, 20, c.f. FIG. 1.
Moreover, the sensor means 30 detects when the film strip 48 laid
initially on the bale 34 moves in front of its working area. The
sensor means 47 may count the rotary arm revolutions, until the
sensor means 48 trips, i.e. the bale 34 is fully wrapped with film
for the first time. Evaluation of the signal values proceeds in
accordance with the procedure described in FIG. 1.
[0058] The embodiment according to FIG. 3 shows a rotary table
device 49 for wrapping a bale 50 of harvested material. This
consists substantially of a wrapping table 53 drivable in the
direction of rotation 52 about a vertical axis 51 and having
drivable, spacedly arranged rollers 54, which rotate the harvested
material bale 50 resting thereon simultaneously in the direction of
rotation 56 about its cylinder axis 55, wherein the bale 50 takes
off a film web 57 from a film supply roll 58 via a stretching
device, not shown, and wraps it around itself. For details of the
structure and mode of operation of such a rotary table device,
reference may be made to EP 0367529 B1. As is visible from FIG. 3,
a first sensor means 59 is attached fixedly but height-adjustably
to the support 60 of the film supply roll 58. For adaptation to
different bale dimensions, the sensor means 59 may also be arranged
in such a way that its distance from the bale 50 is adjustable.
Where the overlap is set at 60%, the sensor means 59 is arranged at
such a height relative to the drawn-off film web 57 that, with the
preset overlap distance X, the sensor means 59 just still covers
the upper area of the film portion 61 lying on the bale 50. As soon
as the overlap falls below the preset overlap X, e.g. due to
excessively fast rotation of the bale 50 in the direction of
rotation 56 relative to rotation of the bale 50 about the vertical
axis 51, the unwrapped area 62 moves in front of the sensor means
59, which sends a corresponding signal to the operator or the
machine control system, in order to return to the desired overlap.
In this way, constant monitoring of the desired film overlap is
ensured.
[0059] A bale standstill sensor, not shown, signals that the bale
50 is not turning about the cylinder axis 55 at the same time as
turning about the vertical axis 51. In this way, wrapping of the
bale with 100% film overlap may be prevented.
[0060] It is essential that the preset minimum overlap distance be
complied with and therefore also monitored. Exceeding of a maximum
overlap distance may be prevented by correct setting of the speed
ratio of bale rotation about the two axes 55, 51, wherein feed
measurement of the bale 50 at its circumference in the direction of
rotation 56 about its axis 55 per rotation of the bale 50 about the
vertical axis 51 could also serve here for monitoring. The measured
feed path per bale rotation must not be smaller than a minimum
amount, which is obtained from the film width and the preset degree
of overlap. Thus, the film overlap within precisely one band width
(minimum/maximum overlap) may be monitored and controlled.
[0061] The second sensor means 63 is associated with the unwrapped
bale area 62 during virtually half a bale rotation about the axis
55 and is arranged likewise in adjustable manner on the support 60
for the film supply roll 58 close above the film web 57 drawn off
from the film supply roll 58. By means of this sensor means 63 and
a further sensor means for the speed of rotation of the bale 50
about the axis 51, the number of bale revolutions about the axis 51
is measured until the entire bale surface has been wrapped in film
for a first time. Conversion of this measured value for control of
bale rotation about its own axis 55 proceeds as for the exemplary
embodiment according to FIG. 1. The sensor means 59, 63 are
arranged outside the path of revolution of the bale 50 about the
axis 51. One of the sensor means may also take the form of a
revolution counter. FIG. 4 is a schematic side view of a rotary
table arrangement at the beginning of a wrapping process. The
rotary table 64 has turned with the bale 65 about a vertical axis
66 and wrapped a first film web 67 about the bale 65 after one
complete revolution. The rollers 68 then turn the bale 65 about its
own axis 69. The bale turning path measured at the circumference
amounts per bale revolution about the vertical axis 65 to the film
width minus the overlap distance of two film webs. During the
second rotation of the bale 65 about the vertical axis 66, a second
film web 70 was wound about the bale 65, which overlaps the first
film web 69 by the distance Y. A first sensor means 71 has been
arranged in the direction of rotation 72 of the bale 65 at a
somewhat smaller distance from the film web 74 arriving from the
film supply roll 73 than corresponds to the desired feed path of
the bale 65 during one bale rotation about the axis 66, i.e. the
film width minus the overlap distance. In the case of proper
overlap, the sensor means 71 detects film. If the bale 65 is turned
by too small a distance, the film webs 67, 70 overlap by too much.
After the relevant bale rotation about the axis 66, the sensor 71
does not detect any film and signals this to the open-/closed-loop
control unit, which corrects the speed ratio in the direction of
the preset overlap.
[0062] The sensor 71 may preferably be so constructed that it
detects one or more film layers. Thus, continuous monitoring of the
wrapping process would also be possible with this sensor means with
more than two film layers. From the third bale rotation, the sensor
would have then to detect two film layers. At the diametrally
opposed bale side, a sensor means 75 could be arranged precisely
outside the second film web 70, which detects whether the bale has
not been moved by too great a feed path in the direction of
rotation 72, which would lead to too small a film overlap. Thus, it
is possible to check whether the actual overlap lies within a
tolerance band. It is possible to arrange one or more sensors 71,
75 only after a quarter rotation of the bale 65 or in addition to
those first mentioned. Finally, a further sensor means 76 has been
provided closely above the drawn off film web 74, which establishes
when the last bale area is wrapped. This is arranged above the film
web 74 coming from the film supply roll 73 and directed towards the
unwrapped end area, which is the last to be wound round with film
during rotation of the bale 65 about the axis 69. Evaluation of
this sensor signal proceeds in accordance with the Example
described in FIG. 1.
* * * * *