Abstract:
A cold frame comprising a housing formed of one or more housing sections with opposed ends walls. The sections include channel-defining end edges interlockable with the end edges of adjacent sections and with the end walls. The sections at the joinders therebetween, forming outwardly directed channels for water exclusion. The sections include, along the opposed side walls thereof, elongate vents with connector bars between the aligned vents of adjacent sections for a gang operation of all of the vents along a side of the cold frame. Each section and end wall incldues positioning blocks mounted thereon for the reception of horizontal alignment pins therethrough and vertical anchoring stakes.

Description:
BACKGROUND OF THE INVENTION 
     The invention is broadly concerned with promoting the growth of plants, and in particular vegetables, under conditions which would normally be considered too severe for proper growth. 
     Adverse conditions could entail many factors including excess moisture or lack of moisture, wind, and most significantly, cold. 
     Various means have been proposed to accommodate such conditions from elaborate greenhouses covering multiple acres to cold frames for individual or small groupings of plants. 
     The use of cold frames is a particularly desirable way to protect outdoor plants from severe ambient conditions. However, it is often difficult to accommodate such frames to differing circumstances as encountered in the field growing of either individual plants by the homeowner or rows of plants by those interested in more extensive plantings. Problems arise both in the actual provision of cold frames in varying sizes, and in controlling such vent means as may be provided, particularly wherein extended length or multiple cold frames are provided. 
     SUMMARY OF THE INVENTION 
     The cold frame of the invention is adapted to enclosed field-growing crops, sealing directly to the earth in surrounding relation thereto for retention of heat and moisture to encourage growth. 
     The cold frame is of a multiple-section construction wherein the length of the frame can be varied through the selective addition and/or removal of sections for an accommodation of crop rows of substantially any reasonable length. Each of the sections is both self-supporting and individually anchored to the ground for a stable construction regardless of the length of the frame. The cold frame of the invention also incorporates a ventilation system comprising vents associated with each section and control components for interconnection and simultaneous actuation of the vents throughout the length of the constructed cold frame. 
     Basically, each section includes opposed sloping roof panels and generally vertical side wall panels. The two opposed ends of each of the sections include peripheral lips or channels adapted to interfit with similar channels on adjacent sections to define water-excluding joinders. The opposed ends of the assembled sections are closed by end walls, each with a peripheral lip or channel interlocking with the corresponding end of the endmost section. The sections, other than for a first starter unit or section include an inwardly directed channel at one end thereof and a corresponding outwardly directed channel at the second end for an internesting of the corresponding edges of adjacent sections. The starter unit includes an outwardly directed peripheral channel at both ends thereof whereby each end of the frame, whether formed only of the starter unit or of multiple sections extending from the starter unit, terminates at the opposite ends in outwardly directed channels which are received within inwardly directed peripheral channels on the end walls, thus maintaining a water-draining channel configuration at each edge joinder along the frame. 
     Each of the sections includes a vent with sliding closure panel along each side wall thereof. Assuming multiple sections, the vents along each side include connector means for simultaneous manipulation of the vent panels along the one side of the frame from one end of the frame. In addition, each of the sections, as well as the two end walls, include position blocks for the accommodation of both alignment bars and anchor spikes for an effective stabilization of both the entire frame and the individual units. 
     Additional details of construction and manner of use, and the objects and advantages residing therein, will become apparent from the more complete description of the invention following hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial perspective view of a cold frame constructed in accord with the present invention; 
     FIG. 2 is an exploded perspective view of the cold frame; 
     FIG. 3 is an enlarged cross-sectional view taken substantially on a plane passing along line 3--3 in FIG. 1; 
     FIG. 4 is an enlarged cross-sectional detail taken substantially on a plane passing along line 4--4 in FIG. 1; 
     FIG. 5 is an enlarged partial cross-sectional detail taken substantially on a plane passing along line 5--5 in FIG. 1; and 
     FIG. 6 is an exploded schematic cross-sectional view longitudinally through a portion of the cold frame and illustrating the relationship of the end joinder constructions. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring now more specifically to the drawings, a cold frame 10 in accord with the present invention basically includes a central housing 12 and opposed end walls 14. 
     The housing 12, depending upon the length of the crop row to be accommodated, comprises at least one, and normally multiple sections 16. In each instance, one of the sections, whether used alone or in combination with other sections 16 constitutes a starter unit or section 16&#39;. Each of the sections 16 and 16&#39; comprise a roof defined by a pair of roof panels 18 sloping downward and outward from a central peak, and side walls 20 sealed to and depending from the outer edges of the roof panels 18. The side walls 20 preferably incline slightly outward from the vertical to allow stacking of the sections for storage purposes, and to also facilitate edge joinder of adjacent sections as shall be explained subsequently. The inclined walls additionally provide for a wider more stable base and increased exposure to external sunlight. As noted in the various cross-sectional details, the roof panels 18 and the side walls 20 are preferably double-wall hollow-core transparent or translucent synthetic resin panels which provide both superior light transmission and thermal insulation, particularly desired for the retention of ground heat to preclude freezing. 
     Each of the sections 16 and 16&#39; include opposed open ends, the full lengths of which include laterally turned edge flanges 22 defined as a continuation of one of the walls of the corresponding double-wall panels which comprise the roof panels 18 and side walls 20 of each section. Each of these lateral turned edge flanges define, with the adjacent section panels, a full length laterally directed channel 24. The two end channels 24 on the starter unit or section 16&#39; are both outwardly directed relative to the interior of the cold frame. On each of the remaining sections 16, the end channel 24 on the end of the section closest to the starter unit 16&#39; is inwardly directed while the end channel 24 on the opposite end of the section 16 is outwardly directed in the manner of both channels on the starter section 16&#39;. Thus, the sections are simply and effectively edge joined by first positioning the starter section 16&#39; and then introducing the inwardly directed end channel of each subsequent section 16, through a downward vertical sliding movement thereof, into the outwardly directed channel of the previously positioned section, either 16&#39; or 16. The last section 16 will terminate in an outer end with an outwardly directed end channel regardless of the number of sections used. The provision of the starter section 16&#39; with two outwardly directed end channels allows for this relationship whether using one or multiple sections. 
     Each of the formed end channels is of a depth slightly less than the thickness of the double-walled panels to provide a smooth joinder between adjacent sections with the internesting channels complimenting each other to provide a section-stabilizing interlock. Further, it would be appreciated that at each end joinder, the outwardly directed end channel thereat provides an effective moisture seal for a positive run-off of rain, particularly desirable under freezing conditions. 
     The end panels or walls 14 are similarly constructed of transparent or translucent hollow-core insulating panels configured to close the opposed open ends of the housing 12 defined by the sections 16 and 16&#39;. The peripheral edge of each of the end panels 14, other than for the horizontal ground engaging edge, includes an inwardly directed edge flange 26 spaced from the inner surface of the end wall 14 to define an inwardly directed channel 28 which compliments and nestably engages within the outwardly directed channel 24 of the adjacent endmost section 16 or 16&#39;. The end panels 14 will mount on the corresponding endmost sections after a positioning of the sections. As will be appreciated, if a minimum length cold frame 10 is to be provided utilizing only a single section, for example in a home garden, only the starter unit or section 16&#39; will be used with an end wall mounted on and enclosing each of the opposed ends of the section 16&#39;. 
     Alternatively, if multiple sections are used, the sections will be edge joined and the end walls mounted to provide the end closures. 
     In order to ensure longitudinal alignment of the sections and preclude lateral shifting therebetween, each of the sections, at the lower edges of the side walls 20 thereof adjacent the opposed ends, is provided with a positioning block 30. Similar blocks 32 are provided on the opposed edges of each end wall 14 adjacent the base thereof. Each of the positioning blocks 30 and 32 includes one or more horizontal alignment bores 34 therethrough and, immediately outward of the horizontal bores 34, one or more generally vertical anchor bores 36. These anchor bores 36 may, as noted in FIG. 3, follow the inclination of the section side wall 20 to which the corresponding block 30 is mounted. 
     Upon an engagement of adjacent sections, or the endmost sections and the end walls 14, and an alignment of the alignment bores 30 of the now-adjacent positioning blocks 30 or 32, elongate alignment pins 38 are extended through the aligned bores 34 in each pair of positioning blocks, note in particular FIGS. 3, 4 and 5. Thus lateral or vertical shifting of adjacent sections relative to each other or to the end walls is effectively prevented. 
     In order to further stabilize the cold frame 10, and anchor the frame to the ground, elongate anchor spikes or stakes 40 are inserted vertically through the anchor bores 36 and driven an appropriate distance into the ground. The slight divergent direction of the anchor spikes 40, as noted in FIG. 3, enhances the effectiveness of the anchors against any tendency for the cold frame to lift, for example under high wind conditions. As suggested in the drawing, both the alignment pins 38 and the anchor spikes 30 include laterally directed or enlarged ends for ease of insertion and removal. 
     Each of the housing sections 16 and 16&#39; includes a pair of vents 42 provided longitudinally along the opposed side walls 20. Each vent includes a longitudinally sliding closure or closure panel 44 slidably received between and retained by upper and lower channel-shaped rails 46 and 48. Sliding travel of the vent closure 44 is limited, and the opposed ends of the rails 46 and 48 connected by vertical end members or posts 50, each of which includes a vertical access slot 52 centrally therein. 
     Each side wall 20, between the corresponding elongate slide rails 46 and 48, has an opening 54 defined therethrough and extending for approximately one-half the length of the vent 42. The vent closure 44, in turn, is of a length substantially equal to or slightly greater than the opening 54 whereby, through a longitudinal manipulation of the closure 44, the vent can be opened or closed, either fully or partially. Actual manipulation of the individual vent closures 44 is facilitated by hook-shaped handles 56 fixed to and extending centrally from the opposed vertical edges of the closure 44. 
     When multiple housing sections are utilized, it is particularly desirable that the aligned vents along each or either side of the cold frame 10 be simultaneously manipulated, preferably from one end of the frame. This becomes more important as the number of sections used and the length of the frame increases to equalize ventilation along the entire length of the frame and avoid the necessity for individual handling and adjusting each vent closure. Accordingly, elongate rigid connector bars 58 are interconnected between the hook handles 56 on aligned vent closures 44 of adjacent sections. The connector bars, in their simplest form, will include vertical apertures 60 through the end portions thereof which are received over the upwardly directed outer ends of the hook handles 56. Each bar 58 will be gravity-maintained on the hook handles 56 for a positive engagement therewith, while at the same time being easily disengaged therefrom for disassembly of the cold frame. The connector bars 58 are freely received through the vertical slots 52 of the end posts 50, the slots 52 being of sufficient height to also accommodate the hook handles 56 should this be necessary at the opposed extreme positions of the closures 44. It will be appreciated that the connectors 58 are of sufficient rigidity to effect both pulling and pushing of the vent closures with the entire ganged system of closures along each side of the cold frame having sufficient structural stability and integrity to accommodate cold frames of substantial length and multiple sections. As desired, and in order to provide a convenient handle for the ganged vents along one side of the frame, an endmost one of the vents can include a connector bar attached thereto and extending beyond the corresponding end wall 14. This is suggested in FIG. 1. 
     The cold frame 10 of the invention, consisting of multiple interengageable sections, can easily be accommodated to a variety of different growing situations, from a small home garden wherein one section would suffice, to a commercial growing situation wherein each cold frame will consist of multiple joined sections. In addition, the relationship of the components of the cold frame allow for a simple expansion or contraction of the frame length as desired in accord with changing conditions. 
     While not limited thereto, two sizes of cold frame sections are presently contemplated, 32&#34;×48&#34; (ten square feet) or 56&#34; 48&#34; (18.66 square feet). The roof panels 18 will preferably incline at approximately 20° to the horizontal, with the sidewalls 20 depending to define an internal angle with the ground of approximately 68°. The angled side walls and the low profile of the assembled cold frame provide an effective wind resistant structure, particularly when combined with the angled insertion of the ground anchors.