Baler for harvested crops

A baler for forming rectangular bales from harvested crop and including a baling channel having an inlet opening, a pressure piston reciprocating in the baling channel and periodically closing and opening the inlet opening, a continuously driven rake conveyor for delivering the harvested crop through the inlet opening of the baling channel synchronously with reciprocating movement of the pressure piston, a switch mechanism for periodically turning off the rake conveyor, and a brake for retraining the rake conveyor for at least one delivery period in its undelivering position outside of a delivery channel, and a control unit for turning on the rake conveyor synchronously with the reciprocating movement of the pressure piston.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a baler for forming rectangular bales from 
harvested crop and including a baling channel having an inlet opening, a 
pressure piston reciprocating in the baling channel and periodically 
closing and opening the inlet opening of the baling channel, a 
continuously driven rake conveyor for delivering the harvested crop 
through the inlet opening of the baling channel synchronously with the 
reciprocating movement of the pressure piston, and an overload clutch for 
separating the rake conveyor from its drive upon overload of the rake 
conveyor for a delivery time period and for automatically connecting the 
rake conveyor with its drive upon expiration of the delivery time period. 
2. Description of the Prior Art 
An important precondition for forming uniform, high-density square bales is 
an adequate filling of the baling chamber or channel. An adequate filling 
should be insured with both thin swaths containing little crop and thick 
swaths containing a large amount of crop, and at different operational 
speeds. Only in this case, desired density and shape of bales can be 
obtained. Prior art discloses a number of solution for effecting an 
adequate filling of the baling channel. 
German Publication DE 2748594 A1 discloses a method and an apparatus for 
loading of the crop with a continuously driven rotary conveyor and with a 
stuffer means for pushing a packing into the baling channel, with the 
conveyor being actuated by a single turn coupling, and driven 
synchronously with the pressure piston. Here, it is important that during 
the formation of bales, always, crop packages, which have as uniform size 
as possible be pushed into the baling channel. At the underside of the 
baling channel, there is provided a delivery channel which is closed by 
the rotary conveyor and serves as a storage space. The stuffer means is 
only then actuated by a claw coupling when the density probe in the 
delivery channel generates a signal indicating that a crop package with a 
desired size and/or thickness has been provided, and the baling channel 
opening is open by the pressure piston. 
If the apparatus operates at a full capacity and a large-volume swath 
and/or at a greater speed, at the beginning of each piston cycle, a 
complete load of the crop is provided, and the stuffer means operates 
without interruptions. When the swath is small and the crop is moistened, 
from three to five pressure piston strokes (idle strokes) take place per a 
single stroke of the stuffer means. The drawback of the apparatus 
disclosed in DE 2748594 A1 consists in that as an overload clutch, which 
protects the stuffer means from overload, a shear bolt is used, with all 
of its known drawbacks. 
In a baler which is disclosed in German Publication DE 4216483 A1, the 
rotary conveyor and the stuffer means are integrated in a single unit with 
a rake conveyor having an overload clutch. The overload clutch separates 
the rake conveyor from its drive for a time period corresponding to the 
time period of the pressure piston stroke when a predetermined load of the 
rake conveyor is exceeded by an amount corresponding to the response 
torque of the clutch. A serious drawback of this baler consists in that 
with thin swath containing little crop, an insufficient amount of crop 
accumulates in the delivery channel. As a result, the filling of the upper 
region of the baling channel is poor, and "banana"-shaped bales are 
formed. 
German Publication DE 19627397 suggests that the rake conveyor of DE 
4216483 A1 be driven, when the swath is thin, with a rotational speed 
equal to a half of the rotational speed of the crank drive of the pressure 
piston. i.e., the pressure piston performs two strokes per each delivery 
stroke of the rake conveyor, with one stroke of the pressure piston being, 
thus, idle. To provide for the reduction of speed of the rake conveyor, 
switch gear is of no use. 
Accordingly, an object of the present invention is to improve the filling 
of the baling channel of the baler, which is disclosed in German 
Publication DE 4216483 A1, in particular with a thing swath with little 
material, without substantially changing the conveying and/or stuffer 
means, and to provide for use of the invention with stuffer means having 
either controllable or uncontrollable rakes. Another object of the present 
invention is to provide simple control means for operating the units of 
the baler according to the present invention. 
SUMMARY OF THE INVENTION 
These and other objects of the present invention are achieved by providing 
a switch mechanism for an intermittent turning-of of the rake conveyor, 
means for retaining the rake conveyor for one or several delivery strokes, 
in an undelivering position of the conveyor outside of the delivery 
channel, and means for restarting the rake conveyor synchronously with the 
reciprocating movement of the pressure position. Thereby, which retaining 
the overload clutch function, there is provided a switch function, which 
is independent from the applied torque, for turning off the rake conveyor, 
if needed, for collecting a crop package of predetermined size and density 
in the delivery channel. The turned-off period is either preset or, e.g., 
is controlled dependent on the filling level of the crop in the delivery 
channel, so that an adequate filling of the delivery channel is insured 
before the actuation of the rake conveyor synchronously with the movement 
of the pressure position. The re-actuation or restarting of the rake 
conveyor can also be controlled by another parameter dependent from, e.g., 
the load applied to the rake conveyor. This permits to avoid overload of 
the rake conveyor upon re-starting. Rake conveyors both with controllable 
and uncontrollable rates can be used without substantial constructional 
changes. With a sufficient swath mass, the switch mechanism performs only 
the conventional overload-protecting function. 
According to a preferred embodiment of the present invention, the switch 
mechanism is formed as a one-turn clutch, a call-shaped clutch, a cam 
clutch, or a wedge clutch that separates the rake conveyor from a rake 
conveyor drive for a period equal to a time period of at least one 
pressure piston stroke. 
Such clutches are partially available on the market and are further 
equipped with means for coupling or uncoupling the locking member. 
A particularly easy control of the switch mechanism is achieved when the 
switch mechanism includes a switch element rotatable together with the 
drive member and displaceable by a locking element pivotal into a path or 
a trajectory of the switch element. The switch element can be secured to 
its support but with a possibility of performing a pivotal movement. 
According to a further embodiment of the invention, for retaining the rake 
conveyor in its undelivering position outside of the delivery channel, a 
instantaneous brake can be associated with the rake conveyor and which can 
be formed, e.g., as a hydraulic or an electromechanical brake. 
Advantageously, the actuation of the instantaneous brake is coupled with 
actuation of the switch mechanism so that the turn-off and retaining 
functions or the turn-on on brake-releasing functions are effected 
simultaneously or with a predetermined phase shift. For restarting the 
rake conveyor, the brake can be released, e.g., shortly before the 
restarting action. This permits to reduce the starting shock and to use 
fewer damping elements. 
A high throughput, high density and uniform shape of the bales is achieved 
when the switch mechanism according to the present invention is used with 
a baler the rake conveyor of which is formed as a plurality of rotatable 
segment members supported next to each other on a common rotational axle, 
with the segment members passing through the pressure piston. Such balers 
combine the advantages of a high throughput, by which the balers having 
segmented rates passing through the pressure piston and throwing the crop 
in front of the end face of the pressure piston, are characterized, with 
advantages of good filling properties by which the balers having a 
pre-pressing chamber or storage space are characterized. Thus, the baler 
with a switch mechanism according to the present invention has a high 
throughput and insures an adequate filling of the baling channel even with 
a thin swatch. The baler with a switch mechanism according to the 
invention insures the formation of bales having a desized density and 
shape, while operating with a high throughput.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A conventional baler, which is shown in FIG. 1, has a baling channel 1 
supported on a mount 2. The mount 2 carries a running wheel axle 3 on 
which running wheels 4 are supported. The baler is connected to a tractor 
(not shown) by a drawbar 5 and is driven by the tractor drive to which it 
is connected by a universal joint shaft 6 connectable with the power 
take-off shaft of the tractor drive. 
A main drive 7 of the baler, which is provided with a fly wheel 8, is 
arranged in the front section of the baling channel 1. The drive 7 
includes a forward drive shaft 9 connectable with the universal joint 
shaft 6, and a cross-shaft 10 which projects from opposite sides of the 
main drive housing. At each of its opposite ends, the cross-shaft 10 
carries an operating crank 11. The main drive 7 also includes a power 
take-off gear 12 for driving operational elements of the baler. 
A pressure piston 13 is arranged in the middle section of the baling 
channel. The pressure piston 13 is connected with the operating cranks 11 
by two connecting rods 14 extending parallel to each other. Upon rotation 
of the cross-shaft 10 in a direction indicated by arrow 15, the pressure 
piston 13 reciprocates between its front end position 16, which is 
indicated with solid lines, and its rear end position 17 which is 
indicated by dash-dot lines. 
The baler further includes a pick-up loader 18 which lifts crop laying in 
swath such as hay, straw or wilted unriped crop from an arable or meadow 
surface and delivers it to the delivery channel 19. In the embodiment of a 
baler shown in the drawings a wide pick-up loader is shown. Two cross-feed 
screws 20 are arranged above the pick-up loader 18. The cross-feed screws 
are offset backward with respect to the pick-up loader. The two cross-feed 
screws 20 limit the width of the lifted swath somewhat to the width of the 
baling channel 1. From the pick-up loader 18, the delivery channel 19 
extends horizontally and is bent upwardly before it opens into or opening 
21 in the baling channel 1. The crop is delivered into the baling channel 
1 from below through the delivery channel 19 and the baling channel 
opening 21 by two rake conveyors 22, 23. Both rake conveyers 22, 23 are 
driven by the main drive 7 via the power take-off year 12. The first rake 
conveyer 22 has a rake with regulated tines 24 the tips of which, during 
operation, move along a trajectory 25 shown with an arrow 26 in the 
direction indicated by arrows. Instead of the first rake conveyor 22, a 
rotor with cutting elements can be provided. The second rake conveyor 23 
consists of spaced from each other, rotatable segment members 28 which are 
supported on a common axle 27 and serve as crop carriers or as 
pre-pressing elements. The segment members 28 are provided with three 
teeth 29 at their conveying edge. The teeth 29 have a saw tooth shape and 
extend backward. During the operation of the baler, the segment members 29 
rotate synchronously with the pressure piston 13 in a direction indicated 
by arrow 30. In the rear position 17 of the pressure piston 13, the 
segment members 29 occupy a position 31 shown with dash dot lines, and in 
the front position 16 of the pressure piston 13, the segment members 29 
occupy a position shown with solid lines. During their circulation, the 
segment members 29 run through slots formed in the pressure piston 13. At 
the end surfaces of the pressure piston 13, the conveying material is 
stripped from the segment members 29. The drive of the second rake 
conveyor 23 includes an overload clutch 33 which temporarily turns off the 
second rake conveyor 23 for a position of the stroke of the pressure 
piston 13 and then automatically actuates the second rake conveyor 23 for 
a maximum of 360.degree. degree of its rotation. As an overload clutch, a 
clutch, which is disclosed and shown in German Publication No. 4,216,483 
can be used. During the operation of the baler, the swath-like crop, which 
is picked up by the pick-up loader 18, is pushed by the first rake 
conveyor 22 into the delivery channel 19 where the crop is picked-up by 
the second rake conveyor 23 and is pushed through the baling channel 
opening 21 into the baling channel 1 in front of the pressure piston 13. 
When a predetermined length of a bale is achieved, it is bound by a bind 
material. To this end, a binding needle 34 and a wrapping device 35, shown 
schematically, are used. FIG. 2 shows a baler provided with an overload 
clutch for the second rake conveyor 23, which is formed, according to the 
invention, as with mechanism 36, the first and second embodiments of which 
are shown in FIGS. 3 and 4, respectively. The switch mechanism can also be 
formed separately from the overload clutch. The operation of the inventive 
switch mechanism, however, will be the same, independent of whether if 
formed as an integral part of the overload clutch or separately therefrom. 
FIG. 3 shows a switch mechanism 36 according to the present invention which 
form an integral part of the overload clutch. The combination overload 
clutch-switch mechanism includes a disc-shaped driven member 37 which is 
connected, e.g., by a channel soothing with a drive shaft 38 of the second 
rake conveyor 23, and a rotatable drive member 39 supported on the drive 
shaft 38 and fixedly connected with a bevel gear 40. The bevel gear 40 
cooperates with a permanently rotatable bevel pinion shaft 41 which is 
driven by the power take-off gear 12. The drive member 39 and the driven 
member 37 are force-lockingly connectable by a pivot lever 42 which is 
formed as a locking member. The drive and driven member 39 and 37 rotate 
together, during the operation of the baler, in a direction shown by arrow 
30. The pivot lever 42 pivots about an axle 43, which supports the driven 
member 37, and is biased against a stop 45 arranged on the driven member 
37 by a biasing force of a tension spring 44 which is arranged between the 
driven member 37 and the pivot lever 42. In its locking position 46, the 
pivot lever is engaged in the driver groove 47 formed in the drive member 
39. The magnitude of biasing force and the lever arm determine the 
transmitted torque. When the predetermined torque exceeds, as a result of 
an overload, a predetermined torque value, the pivot lever 42 pivots 
clockwise to a position 48 shown with dash-dot lines. Upon pivoting the 
pivot lever to its position 48, the drive member 39 freely rotates further 
maximum by an angle of 360.degree., and the driven member 37 and the rake 
conveyor 23 remain stationary. The driven member 37 and the conveyor 23 
are actuated again when the drive groove 47 of the drive member 39 impacts 
the pivot lever 42 which is pivoted by the spring 44, after being 
released, to its initial position 4 (overload control function). 
With a small supply of crop, e.g., because of thin swath, the pivot lever 
42 is pivoted by a pivotably supported pawl 49 into its second position 
48, independent of the torque. As a result of the pivotal movement of the 
pivot lever 42, the driven member 37 and the drive member 39 are separated 
from each other. At the same time, the second rake conveyor 23 is being 
stopped at a position 31 outside of the delivery channel 19, which is 
shown only symbolically in FIG. 2, by a simultaneously actuated 
instantaneous brake 50. The rake conveyor 23 remains in this position 
until a sufficient amount of crop accumulates in the delivery channel 19 
so that a sufficient amount is delivered into the baling channel 1 when 
the rake conveyor is again actuated. The pawl 49 is displaced into its 
position 52a, shown with dash-dot lines, in the path of the pivot lever 42 
by a hydraulic cylinder 51. As a result, the pivot lever 42, after 
pivoting maximum by 360.degree., is forcefully brought into its position 
48 in which no engagement of the drive member 39 with the driven member 37 
takes place. Only after the pawl 49 is pivoted in its initial position 52 
against a stop 54 by a spring 53, the drive member 39 drives the pivot 
lever 42 and therewith the driven member 37, together with the second rake 
conveyor 23, synchronously with the pressure piston 13. Thus, even with 
the thinnest swath, an optimal filling of the baling channel 1 is insured. 
The control of the switch mechanism 36 can be effected in a simple manner 
with the control unit 55. The control unit 55 is so adjusted that, e.g., 
at a thin swath, three pressure piston strokes take place between two 
delivery periods of the second rake conveyor 23. Because the load applied 
to the pressure piston 13 depends directly on the thickness of the packing 
pushed into the baling channel 1, the operation of the second rake 
conveyor 23 can be also controlled dependent on the pressure piston load 
or dependent on the load applied to the first rake conveyor 22. FIGS. 2 
and 3 show, in a very simplified manner, a control block 56 for 
controlling the operation of the second rake conveyor 23 using the switch 
mechanism 36. 
The entire control circuit is best illustrated in FIG. 2. As shown in FIG. 
2, both the second rake conveyor 23 and the pressure piston 13 are 
associated with respective position sensor 57 and 58 the output signals of 
which are communicated, through respective electrical conductors, to the 
control unit 55. The position sensors 57 and 58 measure, respectively, the 
rotational speed of the second rake conveyor 23 and the number of strokes 
of the pressure piston 13. A sensor 59 is arranged in the delivery channel 
19 for sensing the filling height of the material in the delivery channel 
19 or for sensing the initial compression of the material in the delivery 
channel 19. The output signal of the sensor 59 is likewise communicated to 
the control unit 55. A position sensor 60 for sensing the position of the 
pawl 49 likewise has its output connected with the control unit 55. An 
electro-hydraulic control valve 61 also forms part of the control block 56 
which controls the operation of the switch mechanism 36. The operation of 
the control valve 61 is also controlled by the control unit 55. The 
control valve 61 controls the flow of a pressure medium from a pump 62 to 
the first hydraulic cylinder 51 which operates the paw 49. The control 
valve 61 also controls the flow of the pressure medium to a second 
hydraulic cylinder 63 which operates the instantaneous brake 50 of the 
second take conveyor 23. Preset values, which preset a number of strokes 
of the pressure piston 13 per each revolution of the second rake conveyor 
23, are communicated to the control unit 55 via its input 64. If the 
preset value is equal 1, a single stroke of the pressure piston 13 takes 
place per each revolution of the second rake conveyor 23. With a preset 
value equal 3, three strokes of the pressure piston 13 takes place per 
each revolution of the second rake conveyor 23. With a completely 
automatic control of the switch mechanism 36, the number of strokes of the 
pressure piston 13 per each revolution of the second rake conveyor 23 is 
determined, e.g., by the filling height sensor 59 and/or by a force sensor 
65 arranged on the connection rod 14 and which determines the pressure 
piston load. When the pressure piston load is reduced, e.g., below a 
predetermined value, the control unit 55 generates a differential signal 
which controls the control valve 61 so that it actuates the hydraulic 
cylinder 51 which moves the pawl 49 into the position 52a. Simultaneously, 
the control valve 61 actuates the hydraulic cylinder 63 of the 
instantaneous brake 50. As a result, the second take conveyor 23 is held 
in its stop position 31. Only when the filling height sensor 59 indicates 
that the predetermined value has been reached, the control valve 61 is 
controlled so that it provides for the release of the brake 50 and for 
pivoting of the pawl 49 into its initial position 52, and the second rake 
conveyor 23, as a result of the engagement of the pivot lever 42 with the 
driven member 37, performs a filling stroke synchronously with the 
displacement of the pressure piston 13. To prevent overload of second rake 
conveyor 23 upon restarting, preferably, e.g., the response torque of the 
second rake conveyor 23 is determined by a sensor 66 and, taking into 
consideration the actual position of the pressure piston 13 defined by an 
output signal of the sensor 66, the filling cycle is timely triggered in 
such a way that no actuation of the overload protection means 33 of the 
second rake conveyor 23 takes place. The overload protection means 33 
primarily serves to prevent overload in 1:1 region, i.e., at large 
throughputs. 
FIG. 4 shows a combination of a conventional wedge clutch, which functions 
as a one-turn overload clutch, and an inventive switch mechanism 67. The 
switch mechanism 67 includes a drive member 68 which permanently rotates, 
during the operation of the baler, about the drive axle 27 of the second 
rake conveyor 23. The drive member 68 is rotated by a chain drive 69, 
shown only schematically, in a direction of arrow 70. A driven member 71, 
which is arranged coaxially with the drive axle 27, is fixedly connected 
by a channel toothing with the drive shaft 38 of the second rake conveyor 
23. A separate locking member 72 is arranged in the driven member 71. The 
locking member 72 is pushed by an intermediate member 73 and a spring 74 
into engagement with a rectangular recess 75, which is formed in the drive 
member 68. In this way, the locking member 72 connects the drive and 
driven members 68, 71 with each other. For disengagement of the locking 
member 72, a pivot level 76 with an eccentric cam 77 is used. The 
eccentric cam 77 engages a recess 78 in the drive member 68. The pivot 
lever 76 is pivotally supported in a bracket 79, which is welded to the 
drive member 68, by a support axle 88 and is pulled against a stop 82, 
which is secured on the drive member 68, by a spring 81. In the locking 
position, the pivot lever 76 occupies a position 83 shown in FIG. 4 with 
solid lines. In the release position of the drive member 68, the pivot 
lever 76 occupies a position 85 shown with dash-dot lines and in which the 
locking member 72 is not engaged in the recess 75. The switch mechanism 67 
functions in the same way as the switch mechanism 36 the functioning of 
which has been described above. 
Though the present invention has been shown and described with reference to 
a preferred embodiment, such is merely illustrative of the present 
invention, and the invention is not to be construed as to be limited to 
the disclosed embodiment and/or details thereof, and the present invention 
includes all modifications, variations and/or alternate embodiments within 
the spirit and scope of the present invention as defined by the appended 
claims.