US20120240527A1

US20120240527A1 - Baler Mesh Wrap Control With Tension Variance

Info

Publication number: US20120240527A1
Application number: US13/337,254
Authority: US
Inventors: Maynard M. Herron
Original assignee: AGCO Corp
Current assignee: AGCO Corp
Priority date: 2010-12-27
Filing date: 2011-12-26
Publication date: 2012-09-27

Abstract

In an example embodiment, a bale wrap mechanism is configured to wrap a bale with a pre-tensioned wrap material and include a wrap material dispensing mechanism and a wrap material tensioning mechanism. The dispensing mechanism is configured to provide wrap material to a rotating bale in a baling chamber, and the tension mechanism is configured to pretension the wrap material by manipulating the speed of the meshwrap supply relative to the speed of the rotating bale in accordance with a predetermined scheme. The tensioning mechanism may include a brake to manipulate a material wrap payoff roll and a controller to manipulate the brake. A user interface may be used to provide a desired scheme to the controller, such as a desired tension.

Description

CROSS-REFERENCE TO RELATED APPLICATION

Under provisions of 35 U.S.C. §119(e), Applicant claims the benefit of U.S. provisional application No. 61/427,302, filed Dec. 27, 2010, which is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to balers, and more particularly to the wrapping of rotating bales in round balers.

BACKGROUND

A baler may form crop materials into a bale and wrap the formed bale with a wrap material. It is desirable to tightly wrap the bale to preserve the bale's characteristics and prevent the bale from expanding into a soft bale of undesirable size and density. A loosely wrapped bale not only results in a bale of less quality but also leaves the wrap material susceptible to snagging during pickup and transport.
It is often difficult to tightly wrap a bale, however, due to the elastic properties of the wrap material. For example, some wrap material, such as meshwrap, may have compressive forces that are less than the expansive forces of the formed bale, so that the wrapped bale expands after wrapping. Further complicating the matter, different type wraps have different elastic properties and different crops have different expansion properties.
While various prior art attempts have been made to tension the wrap material applied to a bale, these efforts have several shortcomings. For example, previous techniques typically applied a constant tension throughout the wrap cycle resulting in feeding problems and a tension that may not be appropriate for different wrap materials or crops. These techniques also often damaged the wrap material by contacting the wrap material directly. In addition, such prior art systems are not easily manipulated to allow a desired tension level or to adjust for different crops, wrap material, or other factors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side elevational view of an example embodiment of a round baler having a wrapper tension mechanism in which an end of the wrap material is fed to a baling chamber in which the wrap material is at a position A;

FIG. 2 shows an example embodiment of a wrap tension mechanism in a non-feed condition.

FIG. 3 shows an example embodiment of the wrap tension mechanism of FIG. 2 in a feed condition without tension.

FIG. 4 shows an example embodiment of the wrap tensioner in a feed condition with tension.

FIG. 5 shows an example embodiment of a tension wrap mechanism shown in its operational environment.

FIG. 6 shows an example user interface for use with the invention.

FIG. 7 shows an example method of the invention.

OVERVIEW

In an example embodiment, a bale wrap mechanism is configured to wrap a bale with a pre-tensioned wrap material. In an example embodiment, a bale wrap system includes a wrap dispensing mechanism and a wrap tensioning mechanism. The dispensing mechanism is configured to provide wrap material to a rotating bale in a baling chamber, and the tension mechanism is configured to pretension the wrap material by manipulating the speed of the meshwrap supply relative to the speed of the rotating bale in accordance with a predetermined scheme.
In an example embodiment, the tension mechanism comprises a brake configured to slow the payoff of wrap material from a wrap dispenser and a controller to manipulate the brake in accordance with a predetermined scheme. Under one scheme, the brake applies little or no tension during an initial payoff of the wrap material to allow for ease of feeding of the wrap material into the baling chamber and increased tension after the wrap material is sufficiently gripped with the bale. In one example embodiment the brake is arranged to slow a dispenser roll dispensing the wrap material by contacting the inner core of the dispenser roll. This provides for accurate slowing of the wrap material without damaging the wrap material through direct contact.
The controller may also apply the brake to achieve a predetermined stretch of the wrap material. For example, the speed of payoff of wrap material may be slowed relative to the peripheral speed of the bale to achieve a desired stretch of the wrap material.
A user interface may be provided to allow an operator to dictate the particular scheme to be used by the controller. For example, different schemes may be used in response to the different crop material being baled, the type of wrap material being used, or some other factor.
A detection mechanism may be provided to determine the relative speed of the payoff of wrap material and the peripheral speed of the rotating bale in the baling chamber. In one example embodiment a mesh running wheel sensor is used to determine the speed of wrap material payoff and a bale size sensor is used to determine the peripheral speed of the bale. The speed of the periphery of the rotating bale relative to the speed of the payoff of wrap material may be used to determine when the wrap material is positively gripped so that increased tension may be applied to the wrap material. The relative speeds may also be monitored to ensure a desired amount of stretch is provided to the wrap material.
An example method comprises providing wrap material to a rotating bale in a baling chamber and manipulating the tension of the wrap material in accordance with a predetermined scheme. One example method comprises determining whether the wrap material is coupled to the rotating bale in a non-slip manner and if so, then tensioning the wrap material. In an example method, the relative speed of the periphery of the rotating bale is determined with respect to the speed of supply of wrap material provided. If the speeds are approximately equal then this is an indication that the wrap material is gripped with the bale and that tension may be supplied. In another example method, the speed of the payoff of wrap material is slowed relative to the speed of the bale periphery to provide a predetermined stretch of the wrap material.

DETAILED DESCRIPTION

As required, example embodiments of the present invention are disclosed. The various embodiments are meant to be non-limiting examples of various ways of implementing the invention and it will be understood that the invention may be embodied in alternative forms. The present invention will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which exemplary embodiments are shown. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular elements, while related elements may have been eliminated to prevent obscuring novel aspects. The specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention.
Some portions of the detailed description which follows may be presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. Each step may be performed by hardware, software, firmware, or combinations thereof.
Turning to the Figures, FIG. 1 shows, a round baler 20 having a bale wrap system 10 that includes a wrap dispenser mechanism 12 and a wrap tensioning mechanism 14 which works to tightly wrap a bale 16 with wrap material 18. The round baler 20 may be similar to that disclosed in US Patent Publication No. 2010/0192516 which is assigned to the assignee of the present invention and which is hereby incorporated by reference in its entirety to the extent not inconsistent with the present disclosure.
In the example embodiment, the baler 20 includes a bale forming mechanism 34 that comprises a number of rolls and belts that cooperate to define an internal baling chamber 36 that assumes different shapes and sizes throughout a bale forming cycle. The bale forming mechanism 34 may include a belt guiding assembly 68 having a pair of vertically swingable arms 70 located inside the baler 20. The arms 70 may support a pair of idler rolls 62, 64 in a position to directly overlie the bale 16 during its formation within baling chamber 36 and a bale shape sensing wheel 8. The arms 70 may be yieldably biased downwardly so that rolls 62, 64 exert pressure against the top of the bale as it is being formed and the sensing wheel 8 rotates through contact with the rotating bale 16. The sensing wheel 8 may collect data relating to the speed of the rotating bale 16, such as the peripheral speed. As discussed in more detail below, the peripheral speed of the bale may be used in determining what tension to apply to a wrap material provided to the bale 16.
The baling chamber 36 may be open at a bottom to present a baling chamber inlet 80 defined generally between a starter roll 82 and idler roll 54. Power for operating various components of the baler 20 can be delivered by a drive line associated with tongue 26. A front end of such a drive line can be adapted for connection to a power takeoff shaft (not shown) of the towing vehicle, while a rear end of the drive line can be coupled with a gearbox 88 mounted to the chassis 22. The gearbox 88 may be coupled with the various drives for the baler components in a conventional manner, as will be readily appreciated by one of ordinary skill in the art. Additional details of an exemplary round baler, such as baler 20, are disclosed in U.S. Pat. No. 6,050,052 (“the '052 patent”) which is hereby incorporated by reference in its entirety into the present specification to the extent not inconsistent with the present disclosure.
Once the bale 16 of crop material reaches its full size, as illustrated in FIG. 1, it is desirable that the bale 16 be tightly wrapped before being discharged from the baling chamber 36. Thus, the baler 20 further broadly includes the wrapping apparatus 10 for wrapping the formed bale 16 with a wrap material 18 once the bale forming cycle has been completed. While the bale 16 is illustrated as being fully formed, it is also possible to wrap a partially formed bale (not shown) with the wrapping apparatus 10 without departing from the teachings of the present invention.
The wrapping apparatus 10 may be similar to that disclosed in the '516 publication and dispense wrap material 18 to a baling chamber access opening (chamber inlet 80 in the illustrated embodiment) before it can wrap around the formed bale 16. A pan 96 extends generally between a rearward most belt stretch 98 and an idler roll 54. The pan 96 is spaced slightly below the belts 66 as they travel from the idler roll 50, past the idler roll 52, and to the idler roll 54, such that the forwardly moving belts 66 convey the wrap material 18 along pan 96. As discussed in more detail below, the space between the stationary pan 96 and the moving belt 66 serves as a pathway for the wrap material 18.
The bale wrapping apparatus 10 generally includes a housing 100 that contains a roll 110 of wrap material 18 and a wrapper dispensing mechanism 12 for paying out lengths of the wrap material 18 during a bale wrapping cycle. The roll of wrap material 110 is cooperatively supported by a feed roller 116 and a platform 118. As shown particularly in FIG. 8, feed roller 116 and platform 118 each at least partially vertically support roll of supply material 110, with feed roller 116 and roll of supply material 110 defining a nip 117 therebetween.
A hold down assembly 126 is operably attached to the housing 100 and is configured to press against the roll of supply material 110 to bias the roll of supply material 110 forwardly and downwardly where it is cooperatively supported by the feed roller 116 and platform 118.
The feed roller 116 may be supported on a rockable swing frame 136 to allow the feed roller 116 to shift between a belt dis-engaged position (FIG. 2) and a belt-engaged position (FIGS. 3-4). In the engaged position the feed roller 116 is in contact with the belt stretch 98, creating a temporary nip 151 therebetween. A length of wrap material 18 extends from the roll of supply material 110, around a peripheral portion of the feed roller 116 (defined between the nip 117 and the temporary nip 151) and is pulled downstream by rearward most belt stretch 98 along pan 96 and into the chamber inlet 80 where it wraps around the formed bale 16, as will be readily appreciated by one of ordinary skill in the art upon review of this disclosure.
During pay out of the wrapping material 18, the roll of supply material 110 rotates in a clockwise direction as viewed in FIG. 3, while the feed roller 116 rotates in a counterclockwise direction. In the illustrated embodiment, the feed roller 116 is freewheeling, such that the roller 116 is not rotationally driven unless it is in contact with the belt stretch 98 when the feed roller 116 is in the engaged position. In this way, the rotation of the feed roller 116 moves at the same speed as belt stretch 98, helping to eliminate back feeding problems.
Once length of wrap material 18 has been brought into contact with belt stretch 98, such that the wrap material 18 is being paid out into baling chamber 36, it is possible to move the feed roller 116 from an engaged position to an intermediate position (not shown), whereby the downstream engagement between wrap material 18 and the belts 66 continues to pull wrapping material 18 from supply roll 110 around feed roller 116.
At the conclusion of a wrapping cycle, a cutting assembly 140 functions to sever wrapping material 18 such that fully formed and wrapped bale 16 may be removed from baler 20 so that formation of a new bale may begin.
Thus, the wrap mechanism 10 may wrap the bale 16 with a wrap material 18. In order to tightly wrap the bale 16 with the wrap material 18 a tension mechanism 14 may be provided to pretension the wrap material 18. As shown in FIGS. 2-4 the tension mechanism 14 may include a brake 4 and a controller 2 for manipulating the brake 4. The brake 4 may be used to slow the payoff of the wrap material 18 from the wrap roll 110. In an example embodiment shown in FIGS. 2-4, the brake 4 comprises an expandable mandrel 38 that is located in the core 40 of the wrap roll 110. Various brake designs such as drum or disc types could be adapted to perform the braking function. The portions 78 of the mandrel may be expandable so that it may be moved between a contracted position in which the outer surface 76 of the mandrel portions 78 do not contact the inner surface 84 of inner core 40 of the mesh roll 110 and an expanded condition in which the outer surface 76 of the mandrel portions 78 does contact the inner core 40 to provide sufficient friction to slow the rotation of the mesh roll 110 and thereby slow the payoff of the wrap material 18. Thus, by varying the expansion of the mandrel to contact the core of the mesh roll 110, the speed of the payoff of the wrap material 18 can be manipulated.
The expansion and contraction of the mandrel may be controlled by a controller 2 in accordance with a predetermined scheme. For example, the controller 2 may send command signals to actuate the brake 4 in accordance with the predetermined scheme. The controller 2 and the brake 4 may communicate using a CAN bus 92. The controller 2 may comprise hardware, software, and/or firmware. In the example embodiment shown in FIG. 5, the controller 2 includes a memory 120 and a processor 122 communicatively coupled to the memory and configured to execute various instructions. A predetermined scheme may be saved in memory and executed by the processor 98. The processor 98 may send command signals to the brake assembly 4 via a CAN bus 92 to manipulate the brake as desired. For example, the processor may send commands to an actuator of the brake to engage and disengage the brake. As discussed in more detail below, the controller 2 may manipulate the brake 4 to achieve a desired stretch of the wrap material 18 so that the controller 2 and brake 4 define a tension mechanism 14.
FIG. 5 shows the controller 2 in its operating environment as part of a baler control system 130 in which it may form a part. For example, the controller 2 may be part of a larger baler controller that controls other systems of the baler 20 and communicate via a CAN bus 92 with various other components of the baler 20 including a bale wrap system 10 that includes wrap dispenser system 12, the wrap sensor 6, the bale sensor 8, the brake 4, a user interface 160 a wrap subsystem 186, and a variety of other sensors 184 a-n, and subsystems 180 a-n.
A user interface 160 may be provided to receive input from an operator. For example, as shown in FIG. 6, the user interface 160 may include a display 170 for providing information to an operator and a plurality of input keys 172 and a control wheel 174 that that allows a user to provide input. The display may be similar to the main user interface disclosed in AGCO PN 700. The user interface 160 may allow an operator to select the desired tension to provide to the wrap material 18. For example, the user interface 160 may include fields for selection or input by an operator, such as the crop to be baled 171, a desired tension or stretch percentage 173, a duration of time pretension will be supplied 175, etc. This user input may then be used by the controller 2 as part of the predetermined scheme used to control the brake 4.
In one example method, the controller 2 does not tension the wrap material 18 or slow the wrap material payoff until the wrap material 18 is in a non-slip condition. For example, as shown in FIG. 2, in an initial condition prior to the engagement of the feed roller 116 with the belt portion 98, the brake 4 is not actuated. This allows the wrap roll 110 to rotate freely. As shown in FIG. 3, when the feeder roll 116 is moved into engagement with the moving belts 98 the wrap material, gripped by the nip 117 between the feeder roll 116 and the wrap roll 110 and the nip 151 between the feeder roll 116 and the belts 98, is paid off the mesh roll 110. The wrap material 18 then moves between the support pan 96 and the belts 98, such as at point A. To assist the wrap material's 18 movement between the stationary support pan 96 and the moving belts 98 the brake remains in a deactivated condition so that the wrap material 18 is freely paid off the roll 110 as shown in FIG. 3. At this point the wrap material 18 is not sufficiently gripped to apply the brake 4 and obtain pretension. Application of the brake 4 may also lead to difficulties feeding the wrap material into the opening 80.
As shown in FIG. 1, at a point B, the wrap material 18 will move around idler roll 54 so that the wrap material 18 is gripped between the rotating bale 16 and the belts 66. This grips the wrap material 18 in a non-slip condition so that the wrap material 18 may be tensioned without interfering with the feed of the wrap material 18 into the baling chamber 36. As shown in FIG. 4, the brake 4 may then be applied to tension the wrap material 18. When the brake 4 is applied, the mandrel portions 78 expand to contact the core 40 of the wrap roll 110 to thereby slow the rotation of the wrap roll 10 and the pay off of the wrap material 18. When the wrap material 18 is gripped between the bale 16 and idler roll 54 the wrap material the wrap material can be tensioned by slowing the payoff of material from the roll 110 stretches the wrap material 18.
It should be noted that when the wrap material 18 is gripped with the bale 16 the wrap material 18 and the peripheral speed of the bale 16 will be approximately the same. Thus, when these speeds are the same, this is an indication that the wrap material 18 is positively gripped. As shown in FIG. 5 the controller 2 may be in communication with the wrap sensor 6 to determine the speed of payoff of wrap material and the bale sensor 8 to determine the speed of the rotating bale so that the controller 2 can determine when the wrap material 18 is in a non-slip condition and the amount of stretch being applied to the wrap material 18 by analyzing the speed of payoff of wrap material 18 with the speed of the periphery of the rotating bale 16. In one example embodiment, the wrap running wheel 6 detects the payoff speed of the wrap material 18 and the bale shape sensing wheel 8 determines the peripheral speed of the bale but other sensors could be used to determine this information. The controller 2 can change the tension of the wrap material by sending commands to the brake assembly 4 to increase or decrease the braking and thereby change the speed of payoff. As discussed above, If the payoff speed and the bale peripheral speed are equal, then that is an indication that the wrap material 18 is in a non-slip condition, i.e., that the wrap material is positively gripped by the bale and ready for tensioning. The relative speed of payoff and the bale may also be used to determine the amount of stretch being provided by the tensioning. Thus, the controller 2 may manipulate the brake 4 to achieve a desired stretch of the wrap material. For example, if a 5% stretch is desired, the brake 4 may be manipulated to slow the payoff of the wrap material 18 to a speed 5% slower than the bale peripheral speed.
FIG. 7 shows an example method 200 in which the wrap material is pretensioned in accordance with a pre-determined scheme. Such schemes may be provided by an operator using the user interface 160 and stored in memory 122 and retrieved and executed by the processor 120 of the controller 2 to manipulate the brake 4. At block 202 the method is started. For example, the bale wrapping cycle of the baler may be initiated by a wrap subsystem 186 which may use various sensors 184 a-n to determine the start of the wrap cycle. For example, a bale size sensor 28 may be in the form of a rotation sensor located at the pivot axis of the tension arm and used to determine when to initiate the bale wrap or an operator may initiate bale wrapping. After the wrap cycle is initiated, at block 204 wrap material 18 is dispensed from the dispenser 12. For example, the feed roller 116 may be moved into engagement with the belt portions 98 to initiate pay off of the wrap material 18 from the roll 110 as discussed above. Initially, the brake 4 may be in a contracted condition so that the roll 110 freely rotates and the wrap material 18 moves between the pan 96 and the belts 66 and is easily fed into the baling chamber 36.
At block 206 the peripheral speed of the bale 16 is determined. In an example embodiment, the bale shape sensing wheel 8 sends the peripheral speed data to the controller 2. At block 208 the payoff speed of the wrap material may be determined. In an example embodiment, the mesh running wheel 6 provides this data to the controller 2. At block 210 a determination is made as to whether the bale peripheral speed is generally equal to the wrap material payoff speed. This determination may be made by the processor 98. If the speeds are not equal, the analysis is repeated. If the speeds are equal, then at block 212 the brake 4 is applied. For example, the controller 2 may send a command signal to actuate the brake 4 to achieve a desired payoff speed of the wrap material.
At block 212 the amount of stretch of the wrap material 18 may be determined. A desired payoff speed of the wrap material may be calculated by the controller using a desired input stretch value and the present speed of the rotating bale. For example, to achieve a desired 5% stretch the brake 4 could be applied by the controller 2 to slow the payoff speed of the wrap material to 5% less than the peripheral speed of the bale. For example, the relative speed of the wrap material payoff and the bale peripheral speed can be compared and the difference determined and compared with a desired stretch value. For example, the user interface 160 may be used by an operator to enter a desired stretch value. If the desired stretch value is not equal to determined stretch value then the brake 4 may be adjusted to achieve the desired stretch.
At block 218 a determination is made as to whether to complete the tension. For example, a time duration may be provided by an operator using the user interface 160. For example, as shown in FIG. 6 a user may select the amount of time the wrap material 18 is tensioned using the user interface. If it is determined that the tension should be released then the brake 4 is released at block 220. For example, the controller 2 may send a signal to the deactivate the brake 4. The payoff may be stopped at block 222 by moving the feed roller 116 may to disengage from the belts 98 and move mesh deflector 140 to engage the mesh with the cutoff knife. The process may end at block 224. It should be noted that the method 200 shown in FIG. 7 is just one example scheme and that many other schemes may be used.
While the present invention has been described herein with reference to particular embodiments thereof, latitude of modifications, various changes and substitutions is intended in the foregoing descriptions. It is understood that the invention is not to be limited to the particular terms used in the following claims, but that the invention will include any and all embodiments and equivalents falling within the scope of the appended claims.

Claims

1. A system for wrapping a bale in a baler, comprising:

a bale wrap apparatus configured to provide wrap material to a rotating bale in a baling chamber of a baler; and

a bale wrap tensioner apparatus configured to manipulate a pretension of the wrap material after a portion of the wrap material is gripped with the rotating bale.

2. The system of claim 1, wherein the bale wrap apparatus comprises:

a bale wrap dispenser configured to payoff wrap material to the rotating bale.

3. The system of claim 1, wherein the bale wrap tensioner comprises:

a brake configured to manipulate the payoff of a bale wrap dispenser; and

a controller configured to manipulate the brake in accordance with a predetermined scheme.

4. The system of claim 3, wherein the controller is configured to apply the brake after the wrap material is gripped with the rotating bale.

5. The system of claim 3, wherein the controller is configured to apply the brake in accordance with a predetermined scheme.

6. The system of claim 5, wherein the predetermined scheme comprises a predetermined stretch value for the wrap material.

7. The system of claim 5, wherein the predetermined scheme comprises a predetermined time period.

8. The system of claim 5, wherein the predetermined scheme comprises a stretch value in response to a crop value.

9. The system of claim 5, wherein the predetermined scheme comprises a stretch value in response to a wrap material value.

10. The system of claim 1, further comprising:

a detection mechanism configured to determine whether a portion of the wrap material is sufficiently gripped with the rotating bale to tension the wrap material.

11. The system of claim 10, wherein the detection mechanism is configured to determine a peripheral speed of the rotating bale and a payoff speed of the wrap material.

12. The system of claim 10, wherein the detection mechanism comprises:

a bale speed sensor to detect a peripheral speed of the rotating bale; and

a meshwrap payoff sensor to detect a payoff of the wrap material.

13. The system of claim 10, wherein the detection system is configured to determine the relative speed of the wrap material payoff and the peripheral speed of the rotating bale.

14. The system of claim 1, further comprising a user interface configured to receive a desired tension value of the wrap material.

15. The apparatus of claim 14, wherein the tensioner apparatus is configured to tension the wrap material in accordance with the desired tension value.

16. A tension apparatus, comprising:

a brake configured to manipulate the speed of a payoff roll of wrap material without contacting the wrap material, wherein the brake is configured to contact an inner core of a wrap dispenser roll.

17. The tension apparatus of claim 16, further comprising a controller to manipulate the brake in accordance with a predetermined scheme.

18. An apparatus for tensioning wrap material for a rotating bale in a baling chamber of a baler, comprising:

a brake configured to slow the payoff of wrap material from a wrap material dispenser; and

19. The apparatus of claim 18, wherein the controller is configured to apply the brake after the wrap material is gripped with the rotating bale.

20. The system of claim 18, wherein the predetermined scheme comprises a predetermined programmable stretch value for the wrap material.

21. The system of claim 18, further comprising:

22. The system of claim 21, wherein the detection mechanism is configured to determine a peripheral speed of the rotating bale and a payoff speed of the wrap material.

23. The system of claim 21, further comprising a user interface configured to receive a desired tension value of the wrap material.

24. The apparatus of claim 22, wherein the tensioner apparatus is configured to tension the wrap material in accordance with the desired tension value.

25. A method of tensioning wrap material on a rotating bale in a baling chamber of a baler, comprising:

determining whether a wrap material is gripped with a rotating bale of a baler; and

if the wrap material is gripped with the rotating bale, pretensioning the wrap material.

26. The method of claim 25, wherein said determining whether a wrap material gripped with a rotating bale of a baler comprises comparing the relative speed of the periphery of the rotating bale with the speed of payoff of the wrap material.

27. The method of claim 25, wherein said pretensioning the wrap material comprises:

manipulating the speed of the wrap payoff with respect to the peripheral speed of the bale.

28. The method of claim 27, wherein said manipulating the speed of the wrap payoff with respect to the peripheral speed of the bale comprises slowing the payoff speed.

29. The method of claim 28 wherein said manipulating the speed of the wrap payoff with respect to the peripheral speed of the bale comprises braking a wrap dispenser.

30. The method of claim 25 wherein said pretensioning the wrap material comprises:

pretensioning the wrap in accordance with a predetermined scheme.

31. The method of claim 30, further comprising:

receiving the predetermined scheme from an operator.

32. The method of claim 31, wherein the predetermined scheme comprises a scheme which considers the type crop material being baled.

33. The method of claim 30, wherein pretensioning the wrap in accordance with a predetermined scheme comprises pretensioning the wrap to a desired stretch amount.

34. The method of claim 30, wherein pretensioning the wrap comprises:

receiving a desired stretch amount; and

tensioning the wrap material to produce the desired stretch amount.

35. The method of claim 34, further comprising:

detecting the stretch of the wrap material.

36. The method of claim 34, wherein the step of detecting the stretch of the wrap material comprises comparing a peripheral speed of the rotating bale with a payoff speed of the wrap material.

37. The method of claim 30, wherein the step of pretensioning the wrap material comprises:

providing a first tension to the wrap material during initial payoff of the wrap material; and

providing a second tension to the wrap material after the wrap material is gripping by the rotating bale.