Abstract:
An outboard tine device for soil-aerating equipment is disclosed comprising a hub having an aperture, a rotatable shaft within the aperture and mounted on the soil-aerating equipment, an outboard tine assembly comprising a plurality of outwardly protruding tines, and a securing member adjacent an outboard side of the outboard tine assembly removably securing the outboard tine assembly to the hub, wherein the securing member and hub are respectively positioned on opposing sides of and adjacent to the outboard tine assembly, wherein the outboard tine assembly, hub and securing member are positioned outboard of the mounting assembly resulting in the outboard tine assembly being cantilevered from the shaft. A dual outboard tine device is also disclosed. The outboard tine device is directed to uniform aerating and enabling easier replacement of damaged tines.

Description:
FIELD OF THE INVENTION 
   The present invention relates to agricultural equipment, and more particularly to agricultural equipment for use with soil aeration. 
   BACKGROUND 
   It is known that soil needs to be periodically aerated or de-compacted to encourage growth of a crop by facilitating the access of air, moisture, and nutrients to its roots and by providing space for the roots to grow. With relatively large areas, it is usual to effect aeration by means of tractor-towed aerating equipment. The purposes for which a given area is maintained can vary, requiring different kinds of aeration. It may be necessary to regularly aerate sub-soil without significantly disturbing the surface or, alternatively, it may be necessary to aerate an area while also turning over the surface soil. Also, aeration may be necessary with highly compacted soil, for example, in pasture land compacted by grazing animals; in such cases it is also usually necessary not to significantly disturb the surface. 
   Different types of aerating equipment have been employed in the past to effect aeration in different kinds of situations as mentioned above. For example, U.S. Pat. No. 4,383,580 to Huxford describes an aerating implement which is especially useful for aerating soil in pastures where it is necessary not to unduly disturb the surface. To achieve this, the aerating implement has a plurality of shafts rotatably mounted on a frame with their axes at an angle in the range of 70°–90° to the direction of travel, a plurality of substantially planar ground cutting and penetrating members mounted on the shaft with the plane of each cutting member at an angle of 70–90 degrees to the axis of its shaft towards its outer end. Since issuance of the Huxford patent, operation of the particular implement has been altered by re-orienting the cutting members such that the longitudinal centre line of each cutting member does not pass through the axis of rotation of the shaft (as taught in the Huxford patent), but is rather shifted rearwardly relative to the direction of movement of the shaft so that the longitudinal centre line of each cutting member is rearwardly spaced from the axis of rotation of the shaft, and also by twisting each cutting member by a small angle about its longitudinal centre line. 
   However, as suggested above, such an implement is not suitable for situations where it is desired to aerate the sub-soil and also turn over the surface. Another type of aerating implement thus has to be used in such situations, requiring the availability of two different types of aerating implement, which may be cost-prohibitive given the particular operator. 
   Prior attempts to address this problem have sought to provide aerating implements which are adjustable to enable both aeration without substantially disturbing the surface and aeration with turnover of the surface. 
   For example, U.S. Pat. No. 4,840,232 to Mayer discloses soil-aerating equipment which comprises a frame moveable in an intended direction of travel, at least a pair of gangs freely rotatably mounted on the frame for rotation about the longitudinal axis, such gangs extending in rearwardly-inclined opposite directions on opposite sides of a centre line of said frame extending in the direction of travel, means for adjusting the rearward inclination of the gangs to desired angles in the range of from about 90–120 degrees to the direction of travel, each gang carrying a series of soil-engaging substantially planar tines extending therefrom in vertical planes and positioned to sequentially engage and penetrate the soil with consequent rotation of the gangs when the frame is moved in the direction of travel, each tine having a central longitudinal axis which extends behind the gang&#39;s rotational axis at a distance therefrom in the range from about 0.25 to about 1.75 inches, and each tine being twisted about the tine central longitudinal axis at an angle to a vertical plane parallel to the direction of travel in the range of from about 1–30 degrees. 
   It has been found that soil aeration without significantly disturbing the surface can be effected by positioning the gangs at an angle to the direction of travel in the lower part of the angular range taught by the Mayer patent, and that soil aeration with surface turnover can be effected by positioning the gangs at an angle to the direction of travel in the upper part of the specified angular range. An operator can thus utilize the same piece of equipment for both purposes, thereby saving not only the cost of having to provide another item of equipment but also saving time because aeration equipment in accordance with the invention can readily be adjusted for use in one situation or the other. Thus, an operator does not have to return from a work area to another place to change equipment. 
   However, with some aeration equipment comprising at least a pair of gangs each journalled for rotation at their respective ends and supported by bearings at the respective ends where the gangs are typically positioned along a common axis in side-by-side arrangement, a problem arises in that a gap is effected between tine assemblies on adjacent gangs, due to space required to journal the respective ends and provide securement of the aeration device to the equipment frame. Such a gap is often greater than the individual spacing between tines on the gangs, particularly where the tines on each gang are spaced relatively close to each other. The undesirable result is a wide strip of soil intermediate the pair of gangs where no aeration is effected. 
   In order to overcome this problem, the Mayer device incorporated a cantilevered tine assembly at each gang end, outboard of the bearings on which the gangs were journalled. The tines were therefore able to be positioned intermediate the journalled ends of the gangs and thus could aerate the soil in the area intermediate adjacent gangs. 
   However, the cantilevered tine assembly of Mayer was of integral construction, which proved disadvantageous in some situations. Should one of the tines in the integral tine assembly become damaged or irreparably worn, replacement of the whole integral assembly was necessary. This proved to be both expensive and time-consuming, as tines would frequently become broken, particular in rocky areas. 
   SUMMARY OF THE INVENTION 
   There exists a need to provide a cantilevered tine device for aeration equipment of the type disclosed in Mayer, but which also eliminates the requirement to replace the entire tine assembly in the event of breakage of or damage to one of the plurality of tines forming a part of the cantilevered tine gang assembly. 
   According to a first aspect of the present invention there is provided an outboard tine device for soil-aerating equipment comprising:
         a hub having an aperture extending therethrough;   a rotatable shaft member within the aperture;   means to communicate rotational motion of the shaft member to the hub;   means for removably securing the hub to the shaft member;   a mounting assembly in communication with the shaft member for mounting the shaft member on the soil-aerating equipment;   an outboard tine assembly comprising a plurality of outwardly protruding tine members, the outboard tine assembly adapted to rotate with the shaft member, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assembly is moved over the soil; and   a securing member adjacent an outboard side of the outboard tine assembly removably securing the outboard tine assembly to the hub, wherein the securing member and hub are respectively positioned on opposing sides of and adjacent to the outboard tine assembly, whereby rotational motion of the hub is communicated to the outboard tine assembly and the securing member;   wherein the outboard tine assembly, hub and securing member are positioned outboard of the mounting assembly resulting in the outboard tine assembly being cantilevered from the shaft member.       

   According to a second aspect of the present invention there is provided a dual outboard tine device for soil-aerating equipment comprising:
         inner and outer hubs, the inner hub having an aperture extending therethrough;   a rotatable shaft member within the aperture;   means to communicate rotational motion of the shaft member to the inner hub;   means for removably securing the inner hub to the shaft member;   a mounting assembly in communication with the shaft member for mounting the shaft member on the soil-aerating equipment;   inner and outer outboard tine assemblies comprising a plurality of outwardly protruding tine members, the outboard tine assemblies adapted to rotate with the shaft member, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assemblies are moved over the soil, wherein the inner and outer hubs are respectively positioned on opposing sides of and adjacent to the inner outboard tine assembly;   means for communicating rotational motion of the inner hub to the inner outboard tine assembly and the outer hub; and   a securing member adjacent an outboard side of the outer outboard tine assembly removably securing the outer outboard tine assembly to the outer hub, wherein the securing member and outer hub are respectively positioned on opposing sides of and adjacent to the outer outboard tine assembly, whereby rotational motion of the outer hub is communicated to the outer outboard tine assembly and the securing member;   wherein the inner and outer hubs, the inner and outer outboard tine assemblies, and the securing member are positioned outboard of the mounting assembly resulting in the outboard tine assemblies being cantilevered from the shaft member.       

   According to a third aspect of the present invention there is provided soil-aerating equipment comprising:
         a frame movable in an intended direction of travel; and   an outboard tine device comprising:
           a hub having an aperture extending therethrough;   a rotatable shaft member within the aperture;   means to communicate rotational motion of the shaft member to the hub;   means for removably securing the hub to the shaft member;   a mounting assembly in communication with the shaft member mounting the shaft member on the frame;   an outboard tine assembly comprising a plurality of outwardly protruding tine members, the outboard tine assembly adapted to rotate with the shaft member, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assembly is moved over the soil; and   a securing member adjacent an outboard side of the outboard tine assembly removably securing the outboard tine assembly to the hub, wherein the securing member and hub are respectively positioned on opposing sides of and adjacent to the outboard tine assembly, whereby rotational motion of the hub is communicated to the outboard tine assembly and the securing member;   wherein the outboard tine assembly, hub and securing member are positioned outboard of the mounting assembly resulting in the outboard tine assembly being cantilevered from the shaft member.   
               

   According to a fourth aspect of the present invention there is provided soil-aerating equipment comprising:
         a frame movable in an intended direction of travel; and   a dual outboard tine device comprising:
           inner and outer hubs, the inner hub having an aperture extending therethrough;   a rotatable shaft member within the aperture;   means to communicate rotational motion of the shaft member to the inner hub;   means for removably securing the inner hub to the shaft member;   a mounting assembly in communication with the shaft member mounting the shaft member on the frame;   inner and outer outboard tine assemblies comprising a plurality of outwardly protruding tine members, the outboard tine assemblies adapted to rotate with the shaft member, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assemblies are moved over the soil, wherein the inner and outer hubs are respectively positioned on opposing sides of and adjacent to the inner outboard tine assembly;   means for communicating rotational motion of the inner hub to the inner outboard tine assembly and the outer hub; and   a securing member adjacent an outboard side of the outer outboard tine assembly removably securing the outer outboard tine assembly to the outer hub, wherein the securing member and outer hub are respectively positioned on opposing sides of and adjacent to the outer outboard tine assembly, whereby rotational motion of the outer hub is communicated to the outer outboard tine assembly and the securing member;   wherein the inner and outer hubs, the inner and outer outboard tine assemblies, and the securing member are positioned outboard of the mounting assembly resulting in the outboard tine assemblies being cantilevered from the shaft member.   
               

   According to a fifth aspect of the present invention there is provided an outboard tine device for soil-aerating equipment comprising:
         at least one paired outboard tine assembly and corresponding hub, the at least one corresponding hub having an aperture extending therethrough, the at least one outboard tine assembly adjacent to and outboard of the corresponding hub;   a rotatable shaft member within the aperture;   means to communicate rotational motion of the shaft member to the at least one corresponding hub;   means for removably securing the at least one corresponding hub to the shaft member;   a mounting assembly in communication with the shaft member for mounting the shaft member on the soil-aerating equipment;   the at least one outboard tine assembly comprising at least one outwardly protruding tine member, the at least one outboard tine assembly adapted to rotate with the shaft member, such that at least a portion of the at least one tine member penetrates soil when the at least one outboard tine assembly is moved over the soil; and   a securing member adjacent an outboard side of the at least one paired outboard tine assembly and corresponding hub removably securing together an outermost paired outboard tine assembly and corresponding hub, whereby rotational motion of the corresponding hub is communicated to the outboard tine assembly and the securing member;   wherein the securing member and the at least one paired outboard tine assembly and corresponding hub are positioned outboard of the mounting assembly resulting in the at least one outboard tine assembly being cantilevered from the shaft member.       

   According to a sixth aspect of the present invention there is provided an outboard tine device for soil-aerating equipment comprising:
         a hub having an aperture extending therethrough, the hub comprising a first flange;   a rotatable shaft within the aperture;   a spline on the shaft and the aperture keyed to accept the spline, to communicate rotational motion of the shaft to the hub;   a fastening member removably securing the hub to the shaft;   a bearing assembly on the shaft for mounting the shaft on the soil-aerating equipment;   an outboard tine assembly comprising a plurality of outwardly protruding tine members, the outboard tine assembly adapted to rotate with the shaft, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assembly is moved over the soil; and   a second flange adjacent an outboard side of the outboard tine assembly, the second flange removably mechanically fastened to the outboard tine assembly and the first flange, wherein the first and second flanges are respectively positioned on opposing sides of and adjacent to the outboard tine assembly, whereby rotational motion of the first flange is communicated to the outboard tine assembly and the second flange;   wherein the outboard tine assembly, first flange and second flange are positioned outboard of the bearing assembly resulting in the outboard tine assembly being cantilevered from the shaft.       

   According to a seventh aspect of the present invention there is provided a dual outboard tine device for soil-aerating equipment comprising:
         inner and outer hubs, the inner hub having an aperture extending therethrough, the inner hub comprising a first flange, the outer hub comprising a corresponding second flange and an inner flange;   a rotatable shaft within the aperture;   a spline on the shaft and the aperture keyed to accept the spline, to communicate rotational motion of the shaft to the inner hub;   a fastening member removably securing the inner hub to the shaft;   a bearing assembly on the shaft for mounting the shaft on the soil-aerating equipment;   inner and outer outboard tine assemblies comprising a plurality of outwardly protruding tine members, the outboard tine assemblies adapted to rotate with the shaft, such that at least a portion of each tine member sequentially penetrates soil when the outboard tine assemblies are moved over the soil, wherein the inner and outer hubs are respectively positioned on opposing sides of and adjacent to the inner outboard tine assembly;   at least one fastening member securing the first flange to the inner outboard tine assembly and the second flange, thereby communicating rotational motion of the inner hub to the inner outboard tine assembly and the outer hub; and   an outer flange adjacent an outboard side of the outer outboard tine assembly removably securing the outer outboard tine assembly to the inner flange, wherein the outer and inner flanges are respectively positioned on opposing sides of and adjacent to the outer outboard tine assembly, whereby rotational motion of the outer hub is communicated to the outer outboard tine assembly and the outer flange;   wherein the inner and outer hubs, the inner and outer outboard tine assemblies, and the outer flange are positioned outboard of the bearing assembly resulting in the outboard tine assemblies being cantilevered from the shaft.       

   In some preferred embodiments of the present invention, the means to communicate rotational motion of the shaft member to the hub (or inner hub, according to the second and fourth aspects) comprises the shaft member having a polygonal (and most preferably hexagonal) cross section and the aperture of the hub (or inner hub) being keyed to the shaft member. In other preferred embodiments, the means to communicate rotational motion of the shaft member to the hub (or inner hub) comprises the shaft member communicating with the hub (or inner hub) by means of at least one spline. 
   The means for removably securing the hub (or inner hub) to the shaft member preferably comprises at least one fastening member, and most preferably a bolt member and a hole in an outboard end of the shaft member threaded so as to accept the bolt member. The mounting assembly is preferably a bearing assembly on the shaft member, and the securing member, outboard tine assembly (or outer outboard tine assembly, according to the second and fourth aspects) and hub (or outer hub, according to the second and fourth aspects) are preferably mechanically fastened. 
   According to the first and third aspects of the present invention, the securing member preferably comprises a flange removably mechanically fastened to the outboard tine assembly and the hub by at least one fastening member, the hub preferably comprising a second flange whereby the flange is removably mechanically fastened to the outboard tine assembly and the second flange by at least one fastening member; the at least one fastening member preferably comprises a plurality of bolt members passing through the flange, outboard tine assembly and second flange, thereby removably securing the outboard tine assembly to the flange and second flange. 
   According to the second and fourth aspects of the present invention, the means for communicating rotational motion of the inner hub to the inner outboard tine assembly and the outer hub preferably comprises removable mechanical fastening of the inner hub to the inner outboard tine assembly and the outer hub. The inner hub and outer hub preferably comprise first and second flanges respectively, the first flange, inner outboard tine assembly and second flange being removably mechanically fastened by at least one fastening member, and most preferably by a plurality of bolt members passing through the first and second flanges and inner outboard tine assembly, thereby removably securing the inner outboard tine assembly to the first and second flanges. The securing member and outer hub preferably comprise outer and inner flanges respectively, the inner and outer flanges and outer outboard tine assembly being removably mechanically fastened by at least one fastening member, and most preferably by a plurality of bolt members passing through the inner and outer flanges and outer outboard tine assembly, thereby removably securing the outer outboard tine assembly to the inner and outer flanges. 
   A detailed description of exemplary embodiments of the present invention is given in the following. It is to be understood, however, that the invention is not to be construed as limited to those embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, which illustrate exemplary embodiments of the present invention and, together with the description, serve to explain the principles of the invention: 
       FIG. 1A  is a top plan view, partially transparent, of a prior art aeration device having offset tine gangs, without any cantilevered tine assemblies; 
       FIG. 1B  is a front elevation view of the prior art device shown in  FIG. 1A , having offset tine gangs and without any cantilevered tine assemblies; 
       FIG. 2A  is a top plan view, partially transparent, of a second prior art aeration device, having intermediate tine gangs which are not offset but rather situated immediately adjacent each other; 
       FIG. 2B  is a front elevation view of the prior art device shown in  FIG. 2A , illustrating the problematic increased separation distance intermediate the two centre shafts, where no cantilevered tine assemblies are used; 
       FIG. 3A  is a top plan view of a prior art soil-aeration device as described in the Mayer patent, a dual tine assembly of integral construction being cantilevered; 
       FIG. 3B  is a front elevation view of another embodiment of the prior art soil-aeration device as described in the Mayer patent, a single tine assembly of integral construction being cantilevered; 
       FIG. 4A  is a detailed view, partially in section, of the prior art dual cantilevered tine assembly embodiment shown in  FIG. 3A  above; 
       FIG. 4B  is a detailed view, partially in section, of the prior art single cantilevered tine assembly embodiment shown in  FIG. 3B  above; 
       FIG. 5  is a detailed side elevation view of an integral tine assembly of the prior art with integral hub and tines; 
       FIG. 6  is a front elevation view of the integral tine assembly shown in  FIG. 5 ; 
       FIG. 7A  is a top plan view, partially transparent, of a soil-aerating device according to the present invention, having non-offset shafts, and having a pair of cantilevered single tine assemblies on mutually adjacent shafts; 
       FIG. 7B  is a front elevation view, partially transparent, of the soil-aerating device according to the present invention shown in  FIG. 7A  above; 
       FIG. 8  is a detail view of the outboard tine device shown in  FIGS. 7A and 7B  above, namely a single outboard tine device having cantilevered single tine assemblies; 
       FIG. 9  is a detail exploded view of the cantilevered single tine assembly according to the present invention as shown in  FIG. 8  above; 
       FIG. 10  is a detail view of an alternate embodiment of an outboard tine device according to the present invention, namely a dual outboard tine device having a cantilevered dual tine assembly on the left-hand side and a cantilevered single tine assembly on the right-hand side; and 
       FIG. 11  is a detail exploded view of both the cantilevered dual tine assembly and the cantilevered single tine assembly shown in  FIG. 10  above. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   Referring now in detail to the accompanying drawings, exemplary embodiments of the aeration device of the present invention are provided, as well as examples of prior art devices. 
     FIGS. 1A and 1B  provide top plan and front elevation views, respectively, of a prior art soil-aerating device  10 . The soil-aerating device  10  comprises a frame  18  from which support members  16  depend, the support members  16  having bearings  14  at their lower ends for communication with four tine gangs or rollers  12 . The tine gangs  12  are provided with a plurality of tine assemblies  13 . Due to the bearings  14  and support members  16  at opposite ends of the tine gangs  12  taking up space outboard of the tine assemblies  13  and causing a gap between the aeration paths of adjacent tine gangs  12 , the prior art soil-aerating device  10  employed longitudinal alternate staggering of the tine gangs  12  in order to ensure evenly-spaced rows of aerated soil. Such staggering of adjacent tine gangs  12  permitted the bearings  14  and support members  16  to be placed in front of (or behind, as the case may be) a portion of an adjacent tine gang  12 , thereby ensuring that the tine assemblies  13  are evenly spaced a distance “a”, such that there is no aeration path gap when such a device  10  is towed behind other powered machinery such as a tractor. 
   However, although the staggered tine gang configuration addresses the gap problem, space restrictions may make uniform or symmetrical staggering difficult or impossible to achieve. Also, using the device  10  can result in a phenomenon known in the art as “dog-tracking”. The result of dog-tracking is that one side of the device cultivates more aggressively than the other, leaving visible stripes in the land. Dog-tracking usually occurs at larger swing angles, and the tractor steering can create a yaw moment in keeping the mounted device going straight where the tractor does not have a three-point hitch. Where the tractor does not have a three-point hitch, this frequently resulting in patches or areas of soil being poorly aerated, thereby defeating the original purpose of the soil-aerating device  10 . 
   In order to overcome problems of dog-tracking, prior art aeration devices would typically configure tine gangs laterally substantially along a common line, disposed substantially perpendicularly to the direction of travel of the device.  FIGS. 2A and 2B  show top plan and front elevation views of such a prior art soil-aerating device  20 , having tine gangs  22  arranged substantially symmetrically. The soil-aerating device  20  comprises a frame  28  from which support members  26  depend, the support members  26  having bearings  24  at their lower ends for communication with four tine gangs  22 , the tine gangs  22  being provided with a plurality of tine assemblies  23 . 
   Disadvantageously, however, as may be seen from the front elevation view in  FIG. 2B , while the dog tracking problem may have been addressed, a gap is created in the aeration path. Due to lateral space taken up by the bearings  24  and support members  26  which support the tine gangs  22  at opposite ends thereof, such a configuration would typically result in distance “b” between mutually adjacent tine gangs  22  being greater than distance “c” separating each of the tine assemblies  23  on a tine gang  22 . Such greater spacing “b” accordingly resulted in a wide strip of non-aerated soil (or at least wider strip than is the case with the spacing “c”). 
   In order to be able to produce uniformly-spaced strips of aerated soil without experiencing the problem of dog-tracking, the Mayer patent taught a novel device design, as can be seen in  FIGS. 3A to 6 .  FIGS. 3A and 3B  illustrate two embodiments of a soil-aerating device  30  having a frame  31  comprising a front member  32 , side members  34 ,  35 , centre members  36 ,  37 , and intermediate members  38 ,  39 . The frame  31  is provided with a three-point hitch assembly  42  comprising lower couplings  43 ,  44  and an upper coupling  45 . Tine gangs  46  are provided containing tine assembles  47 . Each tine gang  46  is suspended from the frame  31  by pairs of legs  48 . The lower end of legs  48  are connected to each tine gang  46  at a leg bearing  52  inboard of either the first (in  FIG. 3B ) or second (in  FIG. 3A ) tine assembly  47  from each end. Each tine assembly  47  is spaced from an adjacent tine assembly  47  by an annular spacer  51  and from a leg bearing  52  by a shorter spacer  53 . All tine gangs  46  according to Mayer consist of individual sets of tine assemblies  47  integral with a rotating hub  54 . 
     FIG. 4A  is a detailed view, partially in section, of the prior art dual cantilevered tine arrangement shown in  FIG. 3A  and described above. The cantilevered dual tine arrangement is mounted on the shaft  58  by means of a nut  60  threaded onto the shaft  58  with a washer  59 . This prior art dual tine arrangement comprises a pair of tine assemblies  47  each comprising a plurality of tines  55  formed from a casting, cast integral with a metallic hub  54  from which three tines  55  extend radially outwardly in an equally-angularly spaced relationship, i.e. at an angle of 120 degrees between adjacent tines  55 . The hub  54  has a central aperture  56  of hexagonal shape (not shown) and an annular projection  57  on each side. Each tine gang  46  comprises a shaft  58  with a hexagonal section on which the tine assemblies  47  are mounted, with the tine assemblies  47  being keyed to the shaft  58  for rotation therewith. The intermediate tine assembles  47  are spaced from each other by annular spacers  51  which fit at opposite ends over the annular projections  57  of the adjacent tine assembles  47 . A bearing  52  carried by the lower end of the leg  48  is mounted on the shaft  58 . An adjacent tine assembly  47  is spaced from the bearing  52  by shorter-shaped spacers  53  which engage the annular projection  57  of the hub  54  at one end and the bearing  52  at the other end. These components are retained in an assembly on the shaft  58  by washers  59  and nuts  60  on threaded ends of the shaft  58 .  FIG. 4B  is a detailed view, partially in section, of the prior art single cantilevered tine assembly embodiment illustrated in  FIG. 3B  and discussed above, with a basic structure similar to that discussed above regarding  FIG. 4A . 
   Referring now to  FIGS. 5 and 6 , there is provided a detailed view of an integral tine assembly  47 .  FIG. 5  illustrates a detailed side elevation view of an integral tine assembly  47 , while  FIG. 6  illustrates a front elevation view. Each tine assembly  47  is a metal casting with a hub  54  from which three tines  55  extend in equally-angularly spaced relationship, i.e. at an angle of 120 degrees between adjacent tines  55 . The hub  54  has a central aperture  56  and an annular projection  57  on each side. Each tine  55  is in the form of a planar blade extending in a vertical plane from the hub  52  and having a pointed end  61 . A first ground engaging edge  62  extends, when the tine  55  is in a vertical downwardly extending position, in an upwardly and rearwardly inclined direction. A second edge  63  extends from the pointed end  61  to the hub  54  in a vertical direction, and a third edge  64  extends from the end of the first edge  62 . The first edge  62  is bevelled at  65  over the whole of its length, and the second edge  63  is bevelled at  66  over a major part of its length extending from the hub  54 , the bevelling of the first edge  62  being on the opposite side of tine  55  to the bevelling of second edge  63 . 
   Each tine  55  has a central longitudinal axis X midway between and parallel to the edges  63 ,  64  which extend behind the rotational axis of the shaft  58  (indicated at R in  FIG. 5 ), being spaced therefrom by a distance which in this embodiment is 0.625 inches. As shown especially in  FIG. 6 , each tine  55  is twisted about its central axis X by 8 degrees from the vertical plane parallel to the direction of travel, the axis X being perpendicular to the longitudinal axis of the shaft  58 . 
   However, as stated above, the Mayer device was of integral construction, which proved disadvantageous in some situations. Should one of the tines in the integral tine assembly become damaged or irreparably worn, replacement of the whole integral assembly was necessary, an expensive and time-consuming situation, hence the need for the present invention. Two embodiments of the present invention are illustrated by means of  FIGS. 7A ,  7 B,  8 ,  9 ,  10 , and  11 . 
   According to an aspect of the present invention as embodied in  FIGS. 7A and 7B , a soil-aerating device  100  is illustrated comprising a frame  106  for towing behind a vehicle (not shown), the frame  106  having legs  115  depending therefrom, the lower ends of the legs  115  being provided with bearing assemblies  116 . The bearing assemblies  116  communicate with a plurality of tine gangs or devices, two in this embodiment, each tine gang comprising outboard tine assemblies  118  having a plurality of tines  120 , four in this embodiment, the tines  120  similar in structure to those disclosed in Mayer. 
   Referring now particularly to  FIGS. 8 and 9 , each of the tine gangs or devices comprise a single outboard tine assembly  118  positioned outboard of the bearing assembly  116 , the single outboard tine assembly  118  comprising tines  120 . As can best be seen in  FIG. 9 , the gang comprises a hub  102  having an aperture  104  extending therethrough, a rotatable shaft  108  housed within the aperture  104 , and the hub  102  secured to the outboard end  114  of the shaft  108  by means of a bolt  110  engaged within a threaded hole  112  in the outboard end  114  of the shaft  108 , a disc  111  situated between the hub  102  and head of the bolt  110 . To communicate rotational motion of the shaft  108  to the hub  102 , the shaft  108  has a hexagonal cross section, and the aperture  104  is keyed to communicate with that cross section. Although a hexagonal arrangement is set out, it will be clear to anyone skilled in the art that other means of communicating the rotation are possible, such as using other polygonal arrangements or a splined engagement. The bearing assembly  116  communicates with the shaft  108  immediately inboard of the hub  102 . The gang further comprises a flange  122  at the extreme outboard end of the gang, the flange  122  mechanically fastened to the tines  120  of the outboard tine assembly  118  and a second flange  124  on the hub  102  by means of a plurality of bolts  126  extending therethrough. The outboard tine assembly  118 , hub  102 , and flange  122  are therefore positioned outboard of the bearing assembly  116  resulting in the outboard tine assembly  118  being cantilevered from the shaft  108 . 
   Referring now particularly to  FIGS. 10 and 11 , a dual outboard tine device is illustrated, although a single outboard tine device is provided on the right-hand side of the gang for ease of comparison. The dual outboard tine device comprises inner and outer hubs  128 ,  130 , the inner hub  128  having an aperture  132  extending therethrough, the shaft  108  within the aperture  104 , communication of the shaft  108  rotation to the hub  102  by the same means described above. The inner hub  128  is secured to an outboard end  114  of the shaft  108  in the same fashion as was the case with the single outboard tine device, by means of a bolt  110  threadably engaged in a hole  112  in the shaft  108 , a disc  111  situated between the inner hub  128  and head of the bolt  110 . The bearing assembly  116  communicates with the shaft  108  immediately inboard of the inner hub  128 . In the embodiment of this aspect of the invention, there are two outboard tine assemblies, an inner assembly  134  and an outer assembly  136 , each comprising a plurality of tines  120 . The inner hub  128  is provided with a first flange  138  and the outer hub with a second flange  140 , the two flanges  138 ,  140  mechanically fastened together with the tines  120  of the inner outboard tine assembly  134  therebetween, by means of a plurality of bolts  126 . An outer flange  142 , roughly analogous to the flange of the single outboard tine device, is mechanically fastened to an inner flange  144  on the outer hub  130 , the tines  120  of the outer outboard tine assembly  136  therebetween. When fully assembled and secured, the elements shown in  FIG. 11  would have the appearance illustrated in  FIG. 10 . In the single outboard tine arrangement, there is only one tine assembly  118  cantilevered outboard of the bearing assembly  116 , while in the dual outboard tine arrangement there are two tine assemblies  134 ,  136  cantilevered outboard of the bearing assembly  116 . 
   The utility of the present invention becomes clear in the following situation. If an operator (not shown) is using the soil-aerating device  100  to aerate a patch of soil, the problem of dog-tracking is addressed by the outboard cantilever feature of the design. Also, if one of the tines  120  becomes damaged by striking a rock or other submerged danger, or if a flange  122  cracks due to the stresses placed on the tines  120 , the operator can disassemble the device simply by loosening the various bolts  126 ,  110 , replace the damaged tine  120  or flange  122 , and reassemble the device. As can therefore be seen, the present invention provides a gang arrangement on a soil-aerating device that addresses the problem of aeration row gaps, but it also provides an easily disassembled tine assembly structure to enable quick, simple, and inexpensive repairs or replacements when a tine becomes worn or damaged, without requiring the costly replacement of entire integrated assemblies. 
   While particular embodiments of the present invention have been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention and are intended to be included herein. It will be clear to any person skilled in the art that modifications of and adjustments to this invention, not shown, are possible without departing from the spirit of the invention as demonstrated through the exemplary embodiments. For example, while there is currently a flange on the hub, one possible modification would be to eliminate the flange altogether by providing a hub of wider diameter and having the bolts fasten directly to the hub. The invention is therefore to be considered limited solely by the scope of the appended claims.