Abstract:
A netting deployment and recovery system for covering vines and row crops has a collecting and dispensing cart that travels aside the row to be covered while netting is unrolled from a spool and guided overhead to a sweep tube mounted on a boom. In deploying the netting, a sweep tube directs the netting from the spool up over the row such that it spreads outward and lays over the row as the cart moves forward. In removing the netting the sweep tube gathers the relatively open netting at the upper end and conveys it in a compressed form back to the take up reels. The sweep tube is mounted to pivot about the boom in response to excess tension when the netting is deployed or removed. Such pivoting of the sweep tube engages an actuator to modulate the rotation of the take up reel. The orientation of the sweep tube is reversed for deployment and retrieval of the netting. In retrieving the netting the tension of the netting is reduced via the take up spool to avoid breakage. In deploying the netting, take up wheel rotates under a controlled range of tension. The pivot of the sweep tube is preferably resisted by an adjustable spring.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    None 
       BACKGROUND OF INVENTION 
       [0002]    The present invention relates to an improved apparatus and method for dispensing and retrieving crop covering materials. 
         [0003]    Prior methods of dispensing and retrieving crop covering materials, in particular netting intended to protect crops such as grapes from birds, are disclosed in U.S. Pat. No. 5,956,923, which is incorporated herein by reference. 
         [0004]    While the apparatus described in the above patent offers significant improvements over prior methods, it requires significant care and diligence to prevent the netting from breaking, if for example if it is snagged during retrieval. Alternatively, during dispensing of the netting, it can be difficult to dispense the netting under a moderate tension that facilitates its manual spreading out over the crop as it is dispensed. The tension is to high, the netting can break. If it is too slack it tends to bunch up as it dispenses, requiring greater care to spread it out over the crop without tangles. Further, as such netting. 
         [0005]    In principle it wound appear that the tension during dispensing can be controlled by the rate at which the tractor or other vehicle towing or moving reels that hold and then unwind the netting advance in proportion to the unwind rate, this is not the case, as the linear rate of dispensing decreases as the diameter of the wrapped netting decreases as the take up reel empties. As such bird protective netting is expensive and delicate; it requires extra operators to avoid breakage or snagging of the netting. 
         [0006]    It is therefore a first object of the present invention to provide an improved means of dispensing crop protective material, such as bird netting at a controlled tension. 
         [0007]    It is a further objective to provide an automated means of tension control independent of the speed of the vehicle moving the netting reels 
         [0008]    It is a further objective to provide an improved means to retrieve netting that avoids breakage. 
         [0009]    It is still another object of the invention to provide an improved means to automatically retrieve the netting without breakage relatively independent of the speeds of the vehicle housing the take up reels. 
       SUMMARY OF INVENTION 
       [0010]    In the present invention, the first and other object of the invention are achieved by providing a dispensing an retrieval mechanism that comprises a take up mechanism for crop netting, the mechanism comprising: a laterally extending boom, an arcuate sweep tube for collecting open netting at a first end and dispensing compressed netting at the second and opposite end, a rotary pivot coupling said arcuate sweep tube proximate said second end to said laterally extending boom, a spring coupled to at least one of said arcuate sweep tube and laterally extending boom for resisting the rotation of said laterally extending boom about said rotary pivot, an actuator coupled to at least one of said arcuate sweep tube and laterally extending boom for modify the take up or release rate of the compressed netting collected by said arcuate sweep tube in response to a variation in tension of the netting that causes the movement of said rotary pivot. 
         [0011]    A second aspect of the invention is characterized in that the boom optionally includes a rotary coupling for inverting the orientation of the sweep tube between a position for dispensing or taking up the netting. 
         [0012]    The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a plan view of the operative portion of the device deploying netting. 
           [0014]      FIG. 2  is a plan view of the operative portion of the device retrieving netting. 
           [0015]      FIG. 3  is a rear elevation of the operative portion of the device that includes a preferred embodiment of the boom. 
           [0016]      FIG. 4  a rear elevation of an alternative embodiment of the device. 
           [0017]      FIG. 5  is a rear elevation of the device that shows the entire cart. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Referring to  FIGS. 1 through 5 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved netting dispenser-collector with automatic tension control, generally denominated  100  herein. 
         [0019]    In accordance with the present invention,  FIG. 5  is a rear elevation view of the netting dispenser-collector with automatic tension control  100 . 
         [0020]    The netting dispenser  100  includes take up reels for holding and then dispensing or retrieving the netting  10  through an arcuate sweep tube  120 . The protective netting  10  is generally wrapped in a continuous coil around spindle  30  for storage. Thus the take up reel  250  and the associated rotary drive mechanism support and rotate the spindles to either dispense or recover the netting  10 . 
         [0021]    The sweep tube  120  is mounted on a laterally extending boom  110  mounted on top of a vertical supporting pole  230 . The vertical supporting pole  230  extends upward from the base of cart  240 . The cart  240  has either wheel  245  or other ground support structure, such as rails, as it is intended to be pulled by a tractor. However, it is also optional that the cart includes a means to turn the wheels/treads such that it is an independently powered vehicle. The take up reels  250  are also mounted on the base  241  of cart  240 , and includes a drive mechanism  255  as well be further described with respect to different embodiment of the actuator  150  that provides automatic tension control. The actuator  150  includes a pivot coupling  130 , such as a swivel or rotary connector, between the boom  110  and the sweep tube  120 , generally through the mounting fixture  125  that holds the sweep tube  120 . 
         [0022]      FIG. 1  shows a presently preferred embodiment of the actuator  150 . The sweep tube  120  and mounting fixture  125  are shown an alternative position in broken or dashed lines when the actuator  150  is engaged or trigger. The operative principle of the improved netting dispenser-collector is that when the tension on the netting exceed a predetermined level the sweep tube  120  will move, flex or rotate to an alternative position, such as (but not limited to) that shown in  FIGS. 1 and 2 , wherein either the movement, or the sensing of the predetermined force on the sweep tube  120  modulates the drive mechanism  255  of take up reel  250  so as to lower the tension on the netting. Generally, the form of modulation is to release the take up reel  250  from the drive mechanism  255  so that it spins freely. 
         [0023]    In a preferred embodiment, the actuator  150  includes a hydraulic fluid control valve  151 , with a lever  152 . Hydraulic pump drives are commonly used in agriculture equipment as they can be coupled to a hydraulic system of a tractor that uses the rotary motion of the engine to drive a rotary pump. The hydraulic fluid control valve  152  interrupts the flow of hydraulic fluid to a hydraulically operated drive mechanism  255  so that the take up reels  250  can spin freely, releasing tension on the netting  10 . The lever  152  is for manual opening of the valve  151 . In additional to this optional lever  152  actuator for hand operation, the valve also has a release valve button  153  that is either electronically or mechanically depressed to perform the functional equivalent of operating the lever  152 , to allow the take up reels  250  to spin freely. 
         [0024]    It should be appreciated that in alternative embodiments of the invention the actuator  150  can electrically or mechanically decouple the rotary power used to turn the take up reels so that the reels either spin freely, or at a modified speed to decrease or increase the tension on the netting as appropriate. 
         [0025]    Referring back to  FIGS. 1 and 2 , the pivot mechanism  130  is illustrated as being mounted on the boom  110 . The sweep tube  120  generally includes a support and mounting structure  125  that rotates with respect to the pivot mechanism  130 . Arrow  1  in each of  FIGS. 1 and 2  shows the direction of motion of the vehicle/cart assembly  240  that holds boom  110  above the vine or crop row. 
         [0026]    The portion of the pivot mechanism  130  in  FIGS. 1 and 2  mounted to the boom includes a shaft  132  extending outward in the direction of the boom toward sweep tube. A coiled spring  140  surrounds the shaft  132 . 
         [0027]    Preferably the shaft  132  is threaded to receive a nut  133  that can be rotated and thus moved laterally to pre-compress the spring  140 . The pre-compression of the spring  140  increases its relative stiffness and thus the force required to rotate the pivot mechanism  130  and hence is one of many alternative means for varying the preset the tension control level of the apparatus  100 . It should be appreciated that when actuator  150  is an electronic device, the tension control is programmable rather than set by a physical adjustment of a component, such as nut  133 . 
         [0028]    The pivoting portion  135  of actuator  150  is disposed orthogonal to the rotation axis  20  of pivot mechanism  130 . This pivoting portion  135  has a top plate  136  and a side plate  137 . The sweep tube mount  121  can be connected to any portion of this pivoting portion  135 . The side plate  137  has a hole or bore  138  disposed to allow the end of the shaft  132  to extend there through. As this hole or bore  138  is larger than the diameter of the shaft but smaller than the diameter of the spring  140 , the spring  140  is retained on the shaft  132  but disposed to now resist the rotation of the pivoting portion  135  as such rotation urges the side plate  137  against the end of spring adjacent hole  138 . When the tension on the netting  10  reaches a level sufficient to urge the sweep tube  120  to overcome the spring  140  and hence rotate the pivoting portion  135 , an protrusion  165  extending down from the side of top plate  136  opposite side plate  137  will then depresses the release valve button  153 . Thus, valve  151  then opens to divert the hydraulic fluid from drive  255  so that take up reels  255  can spin freely. 
         [0029]    In the dispensing operation of  FIG. 1 , the netting  10  is fed from the take up reels  250  to entry sides  120   a  of the sweep tube  120 , which then directs it upward and laterally to be unraveled at the opposite end  120   b  over the vine or crop row. The adjustable setting of the pole and the boom allow the position of the exit or outboard side  120   b  of the sweep tube  120  above the vines or crops to be protected. During dispensing one end of the netting  10  is anchored to a post or stake at the end of the row. Thus as the cart  240  is driven down the row the take up reel  250  unwinds the coil of netting so that is dispended along the row crop. Generally, depending on the crop dimensions, the netting  10  is then manually spread out as it exits the sweep tube  120  by assistants on opposite side of the crop row. Alternatively, as taught in the &#39;923 patent additional hardware and equipment may be used to spread the netting laterally. 
         [0030]    During dispensing it is desirable to uncoil the netting  10  at the same linear rate, which is linear feet in length of dispensed netting per unit time, at the same speed as the cart  240  move forward. Theoretically, this can be accomplished without a change is stress on the netting  10  as long as these speeds are evenly matched. While it is also possible to allow the stress in the netting to freely spin the take up reels  250  this is generally not desired, as it leads to the uneven dispensing of netting. Thus, it is more preferable to drive the take up reel  250  at the same speed as the cart  240  with a slight tension on the netting so that is can be more readily spread over the crops. Thus, in the preferred mode of operation on dispensing the netting  10 , should the stress exceed the predetermined and desired value, typically no more than about half the tensile strength of the netting, the actuator  150  is intended to release the take up reel  250  from the drive  255  so that is can spin freely. 
         [0031]    Further, it is desired that once this stress is released, rather than having the take up reel  250  continue to speed freely it is preferred that the rotary drive again be engaged. Thus, having spring  140  disposed to opposes the rotation of sweep tube  120  accomplishes this objective, as it continuously urges the sweep tube to move outward so at to release actuator  150 . 
         [0032]    In removal of the netting, as shown in  FIG. 2 , the netting is first manually removed from the end of the crop or vine row and fed into the outer end  120   b  of the sweep tube  120  so that is can be directed from the opposite end  120   a  to the take up reels. In taking up the netting  10  the take up reel  250  must be driven so the netting compresses into the sweep tube. However, should the netting  10  snag, the actuator  150  acts to disengage the take up reel drive  255  until the stress is reduced to the present level. 
         [0033]      FIG. 1  illustrates the configuration of the sweep tube  120  when netting  10  is being released to cover rows crops or vines. Usually the take up reel  250  is allowed to freely rotate, independent of the vehicle/cart speed such that netting  10  is feed out through the sweep tube by the tension exerted by moving the cart. However, it is more desirable to apply the netting  10  with a controlled tension on the roller such that the netting is easier to spread over the crops and does not bunch up on itself after it is dispended. In this case, it is desirable to have the spindle rotate at speed that belays the netting at the same rate as the linear motion of the vehicle. However, it is not sufficient that the netting spindle merely unwind in proportion to the speed of the vehicle, as the length of netting deployed in each turn of the spindle varies with the thickness of netting build up on the spindle. That is, as the spindle  30  starts to unwind and is full of netting each turn deploys a length of netting  10  equal to the current circumference of the netting  10  on the spindle  30 . However, as the netting  10  is depleted from the cylinder, the circumference decreases such that less netting  10  is deployed per turn. Thus, if the tractor or other device moving the cart  240  does not decrease in speed, the tension will increase in the netting unless it can be deployed faster. Thus, using the above tension control mechanism to vary the take up reel  250  rotation speed between a fixed rate, when the tension setting is not exceeded, and the free wheeling mode when it is, prevents the breakage of netting as well as accommodates a range of vehicle speeds making the process easier to control. 
         [0034]      FIG. 3  shows a preferred embodiment of a means to adjust the position of the sweep tube  120  between the dispending and take up positions shown in  FIG. 1  and  FIG. 2   
         [0035]    Preferably the boom  110  is subdivided into an outer portion  110   a  that supports the pivot mechanism  130  and inner portion  110   b  that is vertical supported by upright pole  230 . The inner and outer portions  110   a  and  110   b  of the boom are attached by a pair of mating flanges  112  and  112 ′ via bolts  114 . A rotary axle preferable extends through the inner and outer portion of the boom, being disposed along the horizontal rotation axis  25 . Thus, when bolts  114  are removed the outer portion of the boom  110   a  can be rotated 180 degrees about rotation axis  25  inverting the pivot actuator  150  and thus flopping the sweep tube entrance  110   a  and exit  10   b  positions between the front and back of the cart  240 . Preferably the flanges  112  and  112  have symmetrical pattern of bolt holes with respect to the horizontal center of the boom so that the same holes can be used when the sweep tube position is flopped. 
         [0036]    Flopping the orientation of the sweep tube  120  between take up and deployment is of course only necessary when the cart can only move in one direction, such as when a single tractor hitch is attached to one end. A self powered cart or a cart with a hitch at both ends can be used for deployment and retrieval of netting without flopping the orientation of the sweep tube. 
         [0037]      FIG. 4  shows an alternative embodiment using an electronic actuator  150 ′ to control take up roll  250 . Actuator  150 ′ electronically determines either the rotation about pivot  130  or the torque about axis  20  using any suitable type of stress, strain or pressure gauge. Then, when the predetermined pivoting movement or torque is reached, the actuator  150 ′ through signal cable  156  reduces the tension on the netting, for example as shown electronically disconnecting the take up reel  250  and spindle from the drive mechanism  255 . Alternatively, the actuator  150 ′ can also modulate or speed up the drive mechanism, or the velocity of the cart, to reduce the tension on the cable at a lower level of stress by other means before the take up reel  250  would be disengaged to spin freely, as this would result in the more even dispensing or recovering of the netting  10 . 
         [0038]    It should be appreciated that many alternative arrangements to the pivot mechanism  130  shown in  FIGS. 1 and 2  are possible, thus to the extent that a spring is used to resist the rotary motion of a component having a mechanical actuator, the spring is optionally a torsion spring around the rotary pivot or compression spring mounted transverse to the pivot axis. It should also be appreciated that depending on the location of the take up reels  250  the sweep tube  120  may differ in shape and orientation, either requiring or allowing an alternative disposition of the pivot axis  20 . 
         [0039]    While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.