Abstract:
An agricultural greenhouse with a reversible covering that can be quickly mechanically opened and closed. The top cover is attached to an endless cable system and two side covers are attached to upper and lower cable systems. Upon activation the cables cause the top and side covers to open in one direction and close in the opposite direction.

Description:
[0001]     The benefits under 35 U.S.C. 119 are claimed of provisional patent application ______ filed ______. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Large-scale greenhouse farming operations are becoming more popular as the demand for fresh fruits, vegetables, plants and plant products increases. It is not uncommon to find greenhouse farms covering 10-20 acres which include fixed, permanent structures and which cost upwards of $60,000-80,000 per acre to construct. These greenhouses are considered by farmers to be worth the investment for three reasons: first, earlier crops (the first of extremely perishable crops command premium prices), second, the decrease in weather related crop damage (e.g. rain, hail, fog, excess heat or sunlight) and third, the ability to extend the growing season (avoidance of freezing temperatures).  
         [0003]     The third reason is most important in the northern latitudes and particularly in Canada, Northern Europe and the eastern coast of the United States. Using greenhouses in these regions requires permanent coverage for protection. However, for the first and second reasons mentioned earlier, removable greenhouse coverings would be adequate and thus would have a place in agriculture in the more southern latitudes of the United States, Mexico, Southern Europe and many parts of Asia.  
         [0004]     The cost of removable cover greenhouses is approximately 10-20% of the cost of permanent structures if, during heavy winds, the covers can be removed. This decreased construction investment allows a vast number of farmers to utilize removable covers for reasons one and two above. For example, there are approximately 60,000 acres of early market strawberries grown in California. If farmers can bring their crops to market two weeks early, their per box return would be approximately double that of the later arriving fruit. The same applies to blueberries, blackberries, raspberries and cherries.  
         [0005]     During the ripening period, just prior to and during picking, rain can completely destroy the ready to pick strawberries, blackberries and raspberries. This can be a devastating loss and, when it occurs, the price of the nondamaged commodity increases greatly. After about one week, undamaged fruit comes to maturity and harvest resumes. However, with respect to cherries, the entire crop can be lost.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     It is the purpose of this invention to introduce a new concept in greenhouse agriculture where vast acreage can be covered and uncovered in a few minutes. Uncovering is beneficial when increased photosynthesis or spraying is desired. When winds become excessive to the point of potential damage to the covering, when not needed in the dormant season and when temperatures under the covers exceed critical levels and during fruit pollination and harvesting, the covers can be removed. Covering is desirable when heat accumulation is needed to break dormancy in deciduous fruits, whenever additional heat units are needed to hasten the ripening or growing process and to prevent damaging rains, hail and frost.  
         [0007]     In the broadest aspect, this invention is intended to expand the use of greenhouse horticulture by providing a considerably less expensive structure since the covering can be easily and inexpensively removed and replaced as desired. More specifically, the removable greenhouse covering is divided into three portions, i.e., a top and two sides. The three parts slide back and forth together or separately, as desired, permitting exposure to unobstructed sunlight and wind, partial exposure or complete covering. When completely closed, inside temperatures will rise quickly compared to ambient temperature and the degree of increase can be somewhat controlled by the incremental opening of the roof or side coverings.  
         [0008]     The ability to adjustably cover and uncover the greenhouse structure quickly, even several times per day, is provided by a series of high tensile wires supporting the three sections of covering (top and two sides) and providing guidance during the sliding operations. Cables, running twice the entire length of the greenhouse structure, which can be up to 1200 feet long, in increments of 36-48 feet, are attached at one end of the structure with a pulley at the opposite end and mechanically wound  
         [0009]     or unwound simultaneously by reels placed at one end of the greenhouse. The travel distance of approximately 36-48 feet can be accomplished in ten to thirty minutes depending on the energy requirements of the motors powering the reels. Covering of the plants is accomplished by the clockwise or counterclockwise rotation of a central shaft to which the reels are attached. One reel winds up the cable while the other reel simultaneously releases the cable.  
         [0010]     Exposing the plants is accomplished by pushing the coverings toward the near support system by a yolk connected to the guide wires, the cables and the movable end of the coverings. The coverings collect at the immovable end much like an open shower curtain. In the open position, the three covers resemble a compressed accordion. On covering the greenhouse, the cable directions are reversed and the covers are pulled via the yolks, which are connected to the movable ends of the covers and to the cables.  
         [0011]     The top cover of the greenhouse extends down the sides about two feet forming two short skirts. The two side covers hang to the ground at their inferior edge and are contained inside the short roof skirts so that rain is deflected to the outside and more heat can be trapped inside. The side covers are held firmly in place by grommets attached to superior and inferior wires of the rigid skeleton. To help stabilize the side covers from lateral wind force movement, a third wire at a vertical distance between the inferior and superior wires is disposed on the outside of each side cover. The roof cover is held in place by grommets attached to the skirt edges and to the guide wires. Additional wires support the roof cover so that water can runoff.  
         [0012]     Temperature and wind monitors determine the degree of compression or extension of the covers. At one end of the greenhouse an electric motor provides the energy to compress or extend the covers. If desired, the side covers are partially opened to an amount sufficient to prevent the greenhouse temperature from exceeding a desired level.  
         [0013]     Approximately every forty to fifty feet a support structure is required to stabilize the wires and provide a fixed end for the roof and side covers. This structure supports a superior fixed endoskeleton and inferior removable exoskeleton arms. The inferior exoskeleton arms are removable from the central vertical support structure and support the inferior wires of the side covers and the stabilizing wires. At harvest, the stabilizing wires and supporting exoskeleton must be removed to permit the pickers to reach into the trees or vines for harvesting the fruit.  
         [0014]     The greenhouse covers single or multiple rows of crops depending on the width of the roof. A maximum height of about 15 feet is acceptable. At these heights, the sides, as independent parts of the greenhouse cover, are essential because of the great lateral forces placed on the sides by the wind. However, with a structure less than six feet tall, the sides can be combined with the roof in a single unit. This greatly reduces the cost since a number of grommets, cables and wires would be eliminated.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0015]     In the drawings,  
         [0016]      FIG. 1  is a perspective view showing the greenhouse covers fully retracted, partially retracted and fully extended;  
         [0017]      FIG. 2  is an elevational view from one end of a single tunnel greenhouse;  
         [0018]      FIG. 3  is a partial perspective view showing the roof cover;  
         [0019]      FIG. 4  is a perspective view showing the greenhouse operating cables;  
         [0020]      FIG. 5  is a partial perspective view of one of the side covers and the roof cover for a single tunnel greenhouse;  
         [0021]      FIG. 6  is a top plan view of a single tunnel greenhouse;  
         [0022]      FIG. 7  is a partial elevational view of the coupling means;  
         [0023]      FIG. 8  is a partial perspective view of the roof cover;  
         [0024]      FIG. 9  is a perspective view of a modification of the invention utilizing multiple roof cover units;  
         [0025]      FIG. 10  is a view taken along the line  10 - 10  in  FIG. 9 ;  
         [0026]      FIG. 11  is a view taken along the line  11 - 11  in  FIG. 9 ;  
         [0027]      FIG. 12  is an elevational view of the roof cover yoke;  
         [0028]      FIG. 13  is a perspective view of the modification of the invention utilizing two different types of covers; and  
         [0029]      FIG. 14  is an enlarged perspective view of the modified roof covers.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     In the drawings and with particular reference to  FIG. 1 , the framework for the greenhouse is shown in the form of multiple vertical posts  1 , upper horizontal arms  2  and lower horizontal arms  3 . Lower horizontal arms  3  are attached to vertical posts  1  by means of couplers  4 . In addition, supplementary outer vertical posts  5  extend upwardly from the outer ends of lower horizontal arms  3  and are attached by means of angular couplers  6  to facilitate removal of the exoskeleton component during certain horticultural procedures. Similar inner vertical posts (not shown) can also be utilized with a corresponding inner stabilizing wire.  
         [0031]     As best viewed in  FIG. 4 , the operating system for the greenhouse for the purpose of moving side covers  7  and  8  and roof cover  9  is shown. Each of the side covers  7  and  8  comprises multiple individual panels each one of which extends between adjacent horizontal arms  2  and  3 . Similarly, roof cover  9  comprises multiple individual inverted V-shaped covers each one of which extends between adjacent horizontal arms  2  and vertical posts  1 .  
         [0032]     The operating mechanism for the greenhouse includes dual upper reels  10  and  11  with the ends of continuous cable  12  attached, respectively, to reels  10  and  11  ( FIG. 4 ). The ends of cable  12  are attached to reels  10  and  11  such that when reels  10  and  11  rotate simultaneously, cable  12  is wound up on one of the reels and unwound from the other. Cable  12  extends the entire length of the greenhouse wherein, at the opposite end, it is guided around pulley  13  mounted on post  14 . Yokes  15  are attached to one end edge of each individual panel of roof cover  9  and cable  12  is operably interconnected with yokes  15  by means of clamps  16  and extends through eyelets  12   a  attached to roof cover  9  as best shown in  FIGS. 3 and 8 .  
         [0033]     The side edges of roof cover  9 , in the single tunnel model, are secured by means of eyelets  17  which are slidably affixed to wire  18  at one side edge of roof cover  9  and on the opposite side to wire  19  by means of eyelets  20 . Wires  18  and  19  are secured to the respective ends of upper horizontal arms  2  ( FIGS. 4 and 5 ).  
         [0034]     In similar fashion, the opening and closing mechanism for side covers  7  and  8  includes middle dual reels  21  and  22 . Cable  23  at each end is attached, respectively, to reels  21  and  22  such that each end is wound and unwound in opposite directions. Cable  23  extends from reels  21  and  22  around guiding reels  24 ,  25 ,  26  and  27  ( FIGS. 4 and 6 ).  
         [0035]     The lower opening and closing mechanism for side covers  7  and  8  is similar to the middle opening and closing mechanism and includes lower dual reels  28  and  29 . The ends of cable  30  are attached, respectively, to reels  28  and  29  such that as reels  28  and  29  rotate, cable  30  is wound up on one reel and unwound from the other reel. Cable  30  extends around guiding pulleys  31 ,  32  and  33  and a fourth guiding reel which is not shown in the drawings ( FIG. 4 ).  
         [0036]     Lower horizontal arms  3  can be eliminated if they interfere with horticultural operations. Two additional short side posts can be placed in the ground similar to the single central post shown in  FIG. 2 . These posts would support lower cable  30  while upper cable  23  would remain supported by upper horizontal arms  2 .  
         [0037]     A vertical yoke  34  is affixed to one end edge of each individual side panel of side covers  7  and  8  and cable  23  is affixed to the upper end of vertical yoke  34  by means of clamp  35  and then extends around the greenhouse through eyelets  36  attached to the upper edge of each side cover  7  and  8 . In similar fashion, cable  30  extends around the greenhouse and is attached to the lower end of vertical yoke  34  by means of clamp  37  and extends through eyelets  38 . Supplemental external support wires  5   a  are attached to vertical posts  5  by means of extensions  5   b . Supplemental internal support wires (not shown) could be utilized.  
         [0038]     To complete the operating mechanism for the greenhouse, upper guiding pulleys  24 - 27  are rotatably mounted on the upper ends of shafts  39  and lower guiding pulleys are rotatably mounted on the lower ends of shafts  39 . Finally, reels  10 ,  11 ,  21 ,  22 ,  28  and  29  are affixed to shaft  40  which is rotated in both directions depending on opening or closing desirability of the covers, by means of motor  41 .  
         [0039]     In order to better visualize the opening and closing of the side panels, an examination of  FIG. 6  is helpful. Specifically, the moving cable, as the shaft rotates counterclockwise, opens the lower side panel as shown in  FIG. 6  by compressing this panel to the right while the upper side panel of  FIG. 6  is compressed to the left. This is also seen in operation in  FIG. 1 .  
         [0040]     The upper portion of rotating shaft  40  is engaged or disengaged, as desired, depending on the desired position of the roof cover independent of the side covers ( FIG. 7 ). This is accomplished by means of slip clutches and a solenoid mechanism  42  whereby either the side panels or the roof cover can be opened independently of each other.  
         [0041]     A modified version of the invention is shown in  FIGS. 9-14  whereby the greenhouse is adapted to cover multiple rows of plants.  FIG. 9  is a diagrammatic representation showing roof section A fully covered, section  13  partially covered and section C fully open. Of course, in actual practice only one of these conditions can exist at any given time. The cover opening and closing mechanism is essentially the same as shown in the version depicted in  FIGS. 1-8  and includes roof cover opening and closing cable  101  which is adjoined to the apex of the roof cover by means of eyelets  102  ( FIG. 13 ). Yoke  103  is attached to one end of each roof panel, as best shown in  FIG. 13 . Further, cable  101  is detachably secured to yoke  103  by means of hinged clamp  104  ( FIG. 14 ). Clamp  104  is attached to cable  101  by rotating it to a closed position and securing it in position by means of thumb screw  105 . By a reverse action, clamp  104  is detached from cable  101 . Of course, any like clamping means could be utilized for the purpose of attaching yoke  103  to cable  101 .  
         [0042]     In accordance with this modification, and as shown in  FIGS. 9-14 , the greenhouse roof cover comprises a solid cover  106  and a separate porous cover  107 . Each section of covers  106  and  107  includes a yoke  103  attached to one end thereof. By this means, when it is desired to fully enclose the plants for optimum heat, yoke  103  of cover  106  is attached to cable  101  by means of clamp  104 . The operating mechanism is then engaged to cause cover  106  to be closed by means of cable  101 . On the other hand, if it is desired to provide shade and a degree of ventilation, clamp  104  of cover  106  is detached from cable  101  and clamp  104  associated with cover  107  is attached to cable  101 . Cable  101  is then activated so as to allow cover  107  to extend over the plants.  
         [0043]     As best shown in  FIGS. 10 and 11 , attaching one roof cover to an adjoining roof cover is accomplished by means of attachments  108  and  109  which secure adjoining roof covers together by means of springs  110  wherein each is locked at one end to attachments  108  and  109  through apertures  111  and interlocked at the opposite ends, respectively, to adjoining roof covers  106  or  107  by means of eyelets  112  and  113 .  
         [0044]     Heavy wire  114  extends through the large center apertures of attachments  108  and  109 . To constrict or expand roof covers  106  and  107  evenly additional cables  115   a  and  115   b  may be required. Attachment  108  includes locking mechanism  116  which secures attachment  108  to moving cable  115   a . It is preferred that attachment  108  be positioned immediately adjacent peripheral yoke arms  117  and  118 . Attachments  109  not in close proximity to yoke  103  would be spaced on heavy wire  114 .  
         [0045]     In operation, with the greenhouse cover closed, as shown in  FIG. 4 , when it is desired to open the green house, motor  41  is activated wherein shaft  40  is caused to rotate such that cables  12 ,  23  and  30  are caused to wind up, respectively, on reels  10 ,  21  and  28 . This action causes the side covers  7  and  8  and yoke  34  of each individual side panel  7  and  8  to move in the direction of the arrows shown in  FIG. 6  to positions, wherein each side panel is compressed against the associated horizontal arms  2  and  3 . Simultaneously, cable  12  rotates around pulley  13  such that yokes  15  push each individual panel of roof cover  9  which are compressed against the associated vertical post  1 . Roof cover  9  is then fully opened as depicted in  FIG. 1 . When it is desired to close the greenhouse, motor  41  is simply reversed so that the operating cables move in the opposite direction so as to extend side covers  7  and  8  and roof cover  9  to a partially closed or fully closed condition, as desired.  
         [0046]     Therefore, by this invention, a greenhouse is provided which is easily opened to the elements and provides the minimal wind resistance when fully opened, partially opened to cause the release of heat and which can be fully covered to provide maximum protection for the plants against rain, hail and other elements and provide maximum heat. The invention also includes the ability to utilize a pair of two different types of covers wherein one provides full protection and heat accumulation with the ability to easily convert to a second cover that is porous in nature thereby providing necessary shade and desirable ventilation.