Net severing apparatus for round baler

An agricultural baler for making cylindrical bales of crop material having a sledge assembly moveable between bale starting and full bale positions. The sledge assembly includes a plurality of rollers which cooperate with an apron to define a bale forming chamber. A dispensing mechanism is carried on the sledge assembly for dispensing web material, such as net or the like, into the bale forming chamber whereupon it is wrapped circumferentially around a cylindrical package of crop material in the bale forming chamber. A net supply assembly is associated with the dispensing mechanism to provide net for feeding into the bale chamber via the dispensing mechanism. Included along the path of the net between the supply assembly and the dispensing mechanism is a net severing assembly for cutting the net after it has been wrapped around the cylindrical hay package formed in the chamber. The net severing assembly comprises a cutting element operatively associated with a comb element in a manner that provides improved net cutting.

FIELD OF THE INVENTION 
This invention relates generally to a baler for forming cylindrical bales 
of crop material, commonly referred to as a round baler. More 
particularly, this invention pertains to an improved net severing assembly 
for round bale web wrapping apparatus. 
BACKGROUND OF THE INVENTION 
Prior art round balers generally have a bale forming chamber defined by an 
apron comprising an array of side-by-side belts, transverse slats trained 
on chains, a plurality of rolls or a combination of these various 
elements, e.g., rolls and belts. Crop material, such as hay, is picked up 
from the ground, as the baler travels across the field, and is fed into a 
fixed or expandable chamber where it is rolled up to form a compact 
cylindrical ha package. While still inside the bale forming chamber in its 
compacted form, the outer surface of the package is wrapped with twine or 
web material, such as net, prior to ejecting the wrapped bale from the 
chamber onto the ground for subsequent handling. 
Exemplary of prior art round balers of the general type mentioned above is 
the baler disclosed in U.S. Pat. No. 4,956,968 issued in the name of K. R. 
Underhill on Sep. 18, 1990. In this baler an apron consisting of a 
combination of rolls and belts is used for bale formation. The baler also 
includes a mechanism for supplying net to a dispensing assembly which in 
turn feeds the net material into the bale forming chamber for 
circumferentially wrapping a formed cylindrical package of crop material. 
The dispensing mechanism includes a net insertion arrangement having a 
grasping portion for pulling net from the supply mechanism and inserting 
the free edge, commonly referred to as the tail, into the chamber. 
Subsequent to wrapping, the net material is severed by a cutting device, 
comprising an assembly for thrusting a knife edge transversely through the 
path of the net while net tension is increased causing a severing action 
as the net is pulled against the knife edge. 
In other round balers known in the art, various cutting devices are 
employed as exemplified by the apparatus disclosed in U.S. Pat. No. 
4,597,241, issued Jul. 1, 1986, wherein a pair of opposing knives are used 
to shear the web material. In another known arrangement a knife strikes an 
anvil to provide the severing function as depicted in U.S. Pat. No. 
4,922,690, issued May 8, 1990. Still another prior art mechanism 
contemplates a knife that is projected into a recess on the opposite side 
of the web path to urge the web against a cutting abutment, as shown in 
U.S. Pat. No. 4,599,844, issued Jul. 15, 1986. 
Insofar a the severing element used in round balers is concerned, there are 
also different types used. In addition to the straight knife edge referred 
to above, other known means include a serrated edged knife as disclosed in 
U.S. Pat. No. 4,409,784, issued Oct. 18, 1983. Cutting devices in round 
balers wrapping systems have also been known to utilize a series of 
side-by-side triangular shaped knife elements projected into the path of 
the web material. This latter arrangement is embodied in the round baler 
apparatus disclosed in U.S. Pat. No. 4,604,855 and No. 4,407,113, issued 
Aug. 12, 1986, and Oct. 4, 1983, respectively. 
The web wrapping material used in round balers is another factor having a 
bearing on the net severing assembly. Materials vary from a thin film of 
plastic to numerous types of net. One of the most commonly known net 
materials used in round balers is a woven fabric material, as shown by way 
of example in U.S. Pat. No. 4,569,439, issued Feb. 11, 1986 and No. 
4,570,789, issued Feb. 18, 1986. A second equally as common net material 
used is made from extruded plastic, an example of which is disclosed in 
U.S. Pat. No. 4,781,291, issued Nov. 1, 1988. 
During the general process of making a round bale, as discussed above, the 
package of hay becomes formed and wrapped by a continuous web of material 
while still in the bale forming chamber. At this stage in the process it 
is important that the severing of the net take place trouble free and that 
a substantially straight lateral edge is left on the end of the web that 
remains in the baler to enhance initiation of the next wrapping cycle. A 
straight lateral cut is also desirable from the standpoint of the bale 
that is being discharged to provide a snugly wrapped neat bale that 
facilitates handling. In the past, problems have been encountered when the 
woven net is improperly severed due to, e.g., bunching or sideways 
movement of the net at or prior to impact. Not only is the poor appearance 
and uneven end undesirable but a straggly end can be more readily snagged 
during processing of the next bale or handling of the discharged bale. 
Further, problems have arisen in attempts to provide a cutting means that 
is adaptable to effectively sever woven net as well as extruded net, both 
of which have different physical characteristics. 
SUMMARY OF THE INVENTION 
An important object of the present invention is to provide improved net 
severing apparatus for round balers that solves the above problems while 
still providing a cost effective device that lends itself to ease of 
serviceability. 
In pursuance of this and other important objects the present invention 
provides for a round baler having a chamber in which cylindrical packages 
of crop material are formed into bales, means for feeding the crop 
material into the chamber, and means for rotating the cylindrical hay 
package in the chamber. Further, means are provided in the baler for 
supplying net along a predetermined path, and means for dispensing the 
supplied net into the bale chamber for circumferentially wrapping a 
cylindrical hay package formed in the chamber as it is being rotated. 
According to its broadest aspects the present invention contemplates a 
severing assembly adapted to cause severing of net after it has been 
wrapped around the package to form a bale, wherein the severing assembly 
includes a cutting element for transversely severing the net, and a comb 
element disposed adjacent the cutting element for operatively engaging the 
net being severed. More particularly the severing assembly includes in a 
more limited sense means for mounting the cutting element adjacent the 
predetermined path and means for moving the cutting element through the 
path, and the cutting element comprises a transverse knife having a 
cutting edge that severs the net under conditions where the cutting 
element has been moved through the path. 
The foregoing and other objects, features and advantages of the invention 
will appear more fully hereinafter from a consideration of the detailed 
description which follows, in conjunction with the accompanying sheets of 
drawings wherein one principal embodiment of the invention is illustrated 
by way of example. It is to be expressly understood, however, that the 
drawings are for illustrative purposes and are not to be construed as 
defining the limits of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings for a more detailed description of the 
preferred embodiment of the invention, FIG. 1 shows a round baler 10 of 
the type having an expandable chamber defined by belts and rollers, as 
generally disclosed in U.S. Pat. No. 4,956,958. 
Round baler 10, which incorporates the preferred embodiment of the present 
invention, includes a main frame 11 supported by a pair of wheels 12 (only 
one shown). A tongue 13 is provided on the forward portion of main frame 
11 for connection to a tractor. Pivotally connected to the sides of main 
frame 11 by a pair of stub shafts 15 is tailgate 14 which may be closed 
(as shown in FIGS. 1 and 2) during bale formation or pivoted open about 
stub shafts 15 to discharge a completed bale. A conventional pickup 16, 
mounted on main frame 11, is supported by a pair of suitable wheels (not 
shown). Pickup 16 includes a plurality of fingers or tines 17 movable in a 
predetermined path to lift crop material from the ground and deliver it 
rearwardly toward a floor roll 18, rotatably mounted on main frame 11. 
The bale forming chamber is defined partly by a sledge assembly 20 
comprising a plurality of rollers 21, 22, 23 extending transversely of the 
main frame 11 in the arcuate arrangement seen in FIG. 1-3. Rollers 21, 22, 
23 are journalled at their respective ends in a pair of spaced apart roll 
carrying arms 24, one of which is shown. These arms are pivotally mounted 
inside main frame 11 on stub shafts 26 for providing movement of sledge 
assembly 20 between the bale starting position shown in FIG. 1 and the 
full bale position shown in FIG. 2. Rollers 21, 22, 23 are driven in a 
counter-clockwise direction as viewed in FIGS. 1-3 by conventional means 
(for example, chains and sprockets or gears) connected with a drive shaft 
28 which is in turn connected to the power-take-off of a tractor. A 
starter roll 30 is located adjacent roller 23 and is also driven 
counter-clockwise. A freely rotatable idler roller 31, also carried by 
arms 24, 25, moves in an arcuate path with sledge assembly 20 as it moves 
between its bale starting position (FIG. 1) and full bale position (FIG. 
2). 
The bale forming chamber is further defined by a conventional apron 32 
comprising a plurality of continuous side-by-side belts supported by guide 
rolls 33, 34, 35, 36, 37 which are rotatably mounted in tailgate 14. Apron 
32 is also supported on a drive roll 38, rotatably mounted on main frame 
11. Although apron 32 passes between roller 21 on sledge assembly 20 and 
idler roller 31, it is only in engagement with idler roller 31 and not 
roller 21 which is located in close proximity to the apron belts and 
serves the purpose of striping crop material from the belts, in addition 
to its bale forming function. Suitable coupling means (not shown) 
connected to drive shaft 28 provide rotation of drive roll 38 in a 
direction causing movement of apron 32 along the path indicated generally 
by arrows a and b in FIGS. 1 and 2. An additional guide roll 40 in the 
main frame 11 ensures proper driving engagement between apron 32 and drive 
roll 38. A pair of take up arms 41 (only one shown) are pivotally mounted 
on main frame 11 by a cross shaft 42 for movement between inner and outer 
positions shown in FIGS. 1 and 2, respectively. Take up arms 41 carry 
additional guide rolls 43, 44 for supporting apron 32. Resilient means 
such as coil springs (not shown) are provided to normally urge take up 
arms 41 toward their inner positions (FIG. 1) while resisting movement 
thereof to their outer positions (FIG. 2). 
When the elements of round baler 10 are disposed in the condition shown in 
FIG. 1 with tailage 14 closed, an inner course c of apron 32 extends 
between lower front guide roll 33 and idler roll 31. Rollers 21, 22, 23 in 
this condition are inclined rearwardly on sledge assembly 20 to define 
with course c the initial bale forming chamber, or as sometimes referred 
to, the core starting chamber. Apron inner course c forms the rear wall of 
the chamber while the inwardly facing peripheral surfaces of rollers 21, 
22, 23 define in a general manner a rearwardly inclined cooperating front 
wall. Floor roll 18 defines the bottom of the chamber and starter roller 
30 is spaced from floor roll 18 to provide a throat or inlet for the 
chamber, through which crop material is fed. 
As round baler 10 is towed across a field, pickup tines 17 lift crop 
material from the ground and deliver it through the inlet and thence into 
the bale forming chamber. The crop material is carried rearwardly by floor 
roll 18 into engagement with apron inner course c (FIG. 1) which urges it 
upwardly and slightly forwardly into engagement with rollers 21, 22, 23. 
In this manner crop material is coiled in a clockwise direction as viewed 
in FIG. 1 to start a bale core. Continued feeding of crop material into 
the bale forming chamber by pickup tines 17 causes the apron inner course 
c to expand in length around a portion of the circumference of the bale 
core as the diameter increases. Take up arms 41 rotate from their inner 
position shown in FIG. 1 toward their outer position shown in FIG. 2 to 
provide for expansion of the inner course of the apron in a well known 
manner, i.e., in effect the outer course of the belts of apron 32 are 
diminished in length while the inner courses increase in a like amount. 
After a bale has been formed and wrapped with web material, tailgate 14 is 
opened and the bale is ejected rearwardly. Subsequent closing of tailgate 
14 returns the apron inner and outer courses of the belts of apron 32 to 
the locations shown in FIG. 1, and round baler 10 is ready to form another 
bale. 
During formation of a bale, sledge assembly 20 also moves between a bale 
starting position (FIG. 1) to a full bale position (FIGS. 2 and 3). This 
movement of sledge assembly 20 causes idler roller 31 to move in an 
arcuate path while maintaining apron 32 in close proximity to roller 21, 
thereby allowing roller 21 to strip crop material from the belts of apron 
32 and prevent or reduce significantly the loss of crop material between 
roller 31 and apron 32 during formation of a bale. Sledge assembly 20 is 
pushed outwardly towards its full bale position during bale formation as 
the crop material expands against the rollers and is pulled inwardly by 
apron 32 to the position shown in FIG. 1 during bale ejection without 
utilizing any additional mechanisms. 
Now turning to the bale wrapping system with which the present invention is 
operative, FIG. 1 shows a net dispensing mechanism 45 pivotally mounted on 
sledge assembly 20 and an interrelated cutting assembly 46 (phantom 
outline) pivotally mounted between the side walls 63 on main frame 11. The 
present invention is directed to improvements to cutting assembly 46 as 
will be described in detail hereinbelow. As best seen in FIG. 3, 
dispensing mechanism 45 comprises a pair of levers 47 spaced apart, inter 
alia, by a transverse idler roll 50. Levers 47 are rotatably supported on 
a cross tube 51 (FIG. 1) that extends between arm 24 of sledge assembly 
20. The dispensing mechanism 45 further comprises transverse clamping 
members 52, 53 (see FIG. 2) also extending between levers 47 and arranged 
to dispense into the forming chamber web material s (FIG. 1), such as net 
or the like, from a supply roll 54 disposed in a container 55 carried on 
baler main frame 11. Container 55 has an access lid 56 to accommodate the 
placement or removal of supply roll 54. Clamping members 52, 53 may be 
mounted between levers 47 by bars such as those shown in U.S. Pat. No. 
5,036,642, issued Aug. 6, 1991, which clamping structure and mounting 
arrangement are hereby incorporated by reference. Thus, web material s,s' 
is pulled from supply roll 54 via a slot 57 and guided around roller 50 to 
clamping members 52, 53 of dispensing mechanism 45. 
Referring now to FIGS. 2 and 3, the bale wrapping system includes an 
electro-mechanical control system for sequentially actuating a net brake 
in conjunction with the net dispensing mechanism 45 as it is moved between 
a net feeding operative position, as shown in FIG. 3, and a nonoperative 
retracted position, as shown in FIGS. 1, 2 and phantom outline in FIG. 3. 
This system also provides for proper actuation of the net cutting assembly 
46. To this end, an electric actuator 61 is shown in its retracted 
position in FIGS. 1 and 2 whereas in FIG. 3 it is shown in solid lines in 
its extended position while the retracted position is shown in phantom 
outline. 
Actuator 61 is pivotally mounted to plate 62, which is affixed to the outer 
surface of sidewall 63 of mainframe 11. A link member 64, pivotally 
attached to actuator element 65, is pivoted about fixed pivot pin 66 
between the retracted position shown in FIGS. 1 and 2 and the extended 
position shown in FIG. 3. Affixed to and adapted for rotation with a pin 
66 and inwardly of side wall 63 is lever 67 shown downwardly inclined in 
FIGS. 1 and 2 in the non-actuated position of actuator element 65. A net 
dispensing actuator arm 68 is pivotally connected to lever 67 via pin 70 
inwardly of wall 63, whereby actuator arm 68 moves to the upward position 
shown in FIG. 3 under conditions where actuator element 65 is extended. 
When actuator element 65 is retracted, arm 68 is moved downwardly and net 
dispensing mechanism 45 is moved to the retracted non-operative position 
(FIG. 2). 
Pivotally attached to the lower end of link member 64 is a transverse 
control arm 71 which reciprocates in a generally for and aft direction in 
response to the position of actuator element 65. The right end of control 
arm 71 is primarily supported by fixed flanged roller 72 and secondarily 
supported by knife control roller 73 (see FIGS. 5 and 6), both of which 
extend through control arm slot 74. FIG. 6 depicts conditions where 
actuator element 65 is fully retracted, and FIG. 5 shows control arm 71 
and related elements in an intermediate condition. Net cutting assembly 46 
pivots around a fixed pivot via a stub shaft 75 affixed to plate 76 
secured to the inside surface of side wall 63. 
Secured in the intermediate area of control arm 71 is a ramp element 77 
having a ramp section 78 (FIG. 6) positioned to engage a roller 80 secured 
to a leg member 69 which is integral with net brake control arm 81. A slot 
82 in brake control arm 81 cooperates with knife roller 73 which is 
secured to knife side plate 83. As shown generally in FIG. 3, brake arm 81 
is in its lowermost position when actuator element 65 is in its extended 
position, and thereby lifts net brake element 84 from the surface of the 
net supply roll by pivoting brake mounting arm 85 counterclockwise about 
86 (FIG. 4). A counter roll 87 is pivotally mounted on a fixed bracket 88 
via a counter roll mounting arm 90 and continually held in contact with 
the surface of net supply roll 54 by means of spring 91 which urges brake 
mounting arm 85 downwardly and in turn also urges counter roll mounting 
arm 90 downwardly. The number of rotations of roll 87 accurately 
determines the amount of net dispensed from roll 54. Thus, by counting the 
number of rotations of the counter roll the desired number of wraps or 
fractional wraps can be applied to the bale being formed. 
FIG. 4, which shows the net supply assembly in general, illustrates the 
position of brake element 84 and counter roll 87 when the net from supply 
roll 54' has been partially depleted, as well as the phantom outline 
positions showing counter roll 87 and brake element 84 disposed adjacent 
the supply roll in its less depleted condition. Regardless of the size of 
the net supply roll or the point to which the bale forming process has 
progressed, the counter roll is in continuous contact with the roll. 
Now turning to net cutting assembly 46, it should be noted that it can also 
be referred to as a severing assembly to more generally define a mechanism 
capable of performing the various types of severing functions discussed 
above. A pair of knife side plates 83 (only one shown) are rotatably 
supported to pivot about stub shaft 75. A cutting means 92 is carried by 
and extends transversely between knife side plates 83 in a generally 
downward direction to pass through the path along which the net material 
is dispensed by dispensing mechanism 45, under conditions where the entire 
assembly is dropped. A similar net cutting assembly that operates in the 
same general manner is shown in U.S. Pat. No. 4,956,968, referred to 
above. For the purposes of this invention it is presumed that the cutting 
assembly dimensions permit cutting means 92 to pass through the net path a 
distance sufficient to assure effective severing. 
FIGS. 7-9, showing cutting means 92 in further detail, depict the unique 
structure of the present invention that enables the round baler severing 
assembly 46 to function in an improved manner. Cutting means 92 comprise a 
cutting element 96 and a comb element 97. Aligned apertures 98,99 and 
100,101 facilitate the use of appropriate securing means for attaching 
cutting means 92 to support member 102 of severing assembly 46. More 
particularly, cutting element 96 includes a beveled knife edge portion 103 
extending downwardly from a planar body portion 104 through which 
apertures 98,99 pass, and comb element 97 comprises a straight upper edge 
105 and a toothed lower edge 106. Although the edge 106 is shown as a 
series of side-by-side rounded teeth having a generally sinuous 
appearance, various other tooth shapes could be used and not depart from 
the essence of the invention. 
Before describing the specific operational advantages of the present 
invention, the general operation of the actuators, linkages and various 
other drive mechanisms and the like of baler 10, will be described. First 
turning to the point at which bale B has been formed and it is ready to be 
wrapped with net material, electric actuator 61 is activated while apron 
32 continues to rotate bale B in a clockwise direction as viewed in FIG. 
2. The outer surface of bale B is generally illustrated by heavy broken 
lines 93 in FIGS. 2 and 3. Actuator element 65 of electric actuator 61 
drives control arm 71 from left to right and net dispensing actuator arm 
81 from the solid line position of FIG. 2 to the solid line position of 
FIG. 3. This rotates the dispensing mechanism 45 from the position shown 
in FIG. 2 to position shown in FIG. 3. As the dispensing mechanism 45 
moves toward its dispensing position (FIG. 3), the cutting assembly 46 is 
rotated clockwise to the non operative position shown in FIG. 3 and 
clamping members 52, 53 move into a gap between roller 21 and apron 32. 
Meanwhile, net brake element 84 has been removed from the surface of 
supply roll 54 while counter roll 87 is maintained in operative contact 
therewith permitting the tail of the net material gripped between clamping 
members 52, 53 to be inserted through the gap into the bale forming 
chamber whereupon it is dragged downwardly and caught in the nip between 
roller 21 and bale B which are rotating in opposite directions. The net 
material is then dispensed along a path from the supply roll 21 via slot 
57, around idler roller 50, between clamping members 52, 53, and then 
through the gap into the bale forming chamber where it is wrapped 
circumferentially around bale B while the bale continues to be rotated by 
apron 32. Counter roll 87 maintains light continuous contact with the 
surface of supply roll 54, at all times, thus permitting a minimum drag 
during dispensing. 
After bale B has been wrapped with one or more layers of the net material, 
electric actuator 61 is reversed thereby moving dispensing mechanism 45 
from the position shown in FIG. 2 to the position shown in FIG. 3. When 
dispensing mechanism 45 has been retracted, net cutting assembly 46 is 
rotated counterclockwise (FIG. 6) so that cutting means 92 is dropped 
downwardly at the appropriate time into contact with the expanse of net 
material extending from clamping members 52, 53 of dispensing mechanism 45 
to the periphery of roll 21. More specifically, knife side plates 83 
rotate about stub shaft 75 under conditions where knife control roller 73 
slides upwardly in brake arm slot 82 upon reaching the ramp 94 in slot 74 
in transverse control arm 71. Cutting means 92 cuts the net material and 
leaves a succeeding tail which is gripped by clamping members 52, 53 for 
future insertion into the bale forming chamber when the next bale is ready 
to be wrapped with net material. Prior to cutting, the net brake has been 
actuated by control arm 81 which travels upwardly via slot 82 when ramp 78 
is clear of roller 80, which actuation permits braking force to be applied 
on the net resulting in necessary tension during cutting. 
Now turning to the unique configuration of cutting means 92, the tips 107 
of the toothed lower edge 106 of comb element 97 extend initially into the 
path of the net material which discourages both lateral and transverse 
motion of the net. By virtue of its tension the net is not permitted to 
pull over the comb element and side-to-side bunching is likewise deterred 
when comb tips 107 protrude through the mesh of the net, regardless of 
whether fabric or extruded net is being used. The lateral strands of the 
net are guided to the beveled knife edge 103 by the gentle curvature of 
toothed lower edge 106 whereupon the tension is provided causing severing 
in a known manner. Because of the nature of comb element 97 and its 
engagement with the net, only a limited number of strands are urged 
against the knife edge section between adjacent teeth, which number is 
determined by the net configuration and the spacing between tips 107. This 
prevents the necessity of a small portion of the knife engaging a 
proportionately large number of strands as would be the case if bunching 
were not obviated. Further, the transverse strands of the net 
simultaneously engage the leading surface of the comb and thereby enhance 
the ability to sever adjacent transverse strands by uniformly hindering 
traversal of the net during severance. 
While the preferred structure in which the principles of the present 
invention have been incorporated is shown and described above, it is to be 
understood that the invention is not to be limited to the particular 
details, as shown and described above, but that, in fact, widely different 
means may be employed in the practice of the broader aspects of the 
invention.