Abstract:
A tine holder for holding a plurality of aerator tines has a plurality of substantially vertical, tapered bores. A tapered collar is adapted to be received in each bore with the collar being split so that the collar contracts as the collar is slid into the bore. The upper end of an aerator tine is inserted into each collar before the collar is inserted into the bore such that the contraction of the collar as the collar is thereafter slid into the bore will suffice to tightly grip and hold each tine in the tine holder. A tool is provided for providing enough leverage on the collar to slide the collar over final portions of its movement as the collar slides into the bore during tine installation or to slide the collar over beginning portions of its movement as the collar slides out of the bore during tine removal.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to a turf aerator for punching aeration holes into the ground to relieve compaction of the turf, to facilitate the entry of air and water into the turf, and to thereby enhance the growth and health of the turf. More particularly, this invention relates to a holder for mounting one or more tines to the aerator for forming aeration holes. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is well known in the turf care industry that the health of the turf can be enhanced by periodically aerating the turf. Aerating the turf involves punching an array of spaced holes into the ground over the area of the turf that is to be aerated. Such aeration holes relieve soil compaction and facilitate the entry of air and water into the turf. This has a beneficial effect on the turf and leads to healthier, more vigorous turf. 
         [0003]    Various aerators have been developed for aerating turf areas. One aerator uses a vertically reciprocal array of tines that first punch down into the ground and then are lifted up out of the ground to form the aeration holes as the aerator moves over the turf area. The tines are arranged in groups on different tine holders and are reciprocated up and down out of phase with one another. U.S. Pat. Nos. 6,561,282 and 7,096,969, both owned by The Toro Company, the assignee of this application, disclose aerators with vertically reciprocal tine arrays. Toro also makes and sells aerators of this type as in its ProCore 648 aerator among others. 
         [0004]    In aerators of this type, the tine holders that carry the tines usually comprise a pair of parts that are clamped together by bolts. Each part of the tine holder has a semi-cylindrical groove that forms one half of a cylindrical bore that will hold an upper end of one of the tines. In installing tines in such a tine holder, the two parts of the holder are separated from one another, the upper ends of the tines are then laid into the semi-cylindrical grooves in a first part of the tine holder, the second part of the tine holder is then overlaid onto the first part with the semi-cylindrical grooves in the second part overlying the other half of the upper ends of the tines, and then the two parts are rigidly bolted together. The tines are tightly clamped within the bores formed by the two parts when the two parts of the tine holder are bolted together. 
         [0005]    While effective, this type of tine holder can be difficult and time consuming to take apart in the event one or more tines need to be replaced. It is often the case that only one tine in the group of tines held by the tine holder might be bent or broken or unduly worn, thus requiring replacement, while the other tines are fine. Nonetheless, the entire tine holder must still be disassembled, the tine that needs to be removed must be taken out and replaced with a new tine, and then the entire tine holder must be reassembled. When the tine holder is disassembled, the other tines can easily fall out of the tine holder, thus requiring that they be picked up and reinserted. All of this is made more difficult since the tine holder is often caked or covered with dirt or soil. 
         [0006]    Accordingly, there is a need in the aerator art for a tine holder that permits quick and easy replacement of the tines on an individual tine-by-tine basis, yet securely holds the tines during use of the aerator. 
       SUMMARY OF THE INVENTION 
       [0007]    One aspect of this invention relates to a tine holder for use with a turf aerator, the tine holder being driven by the turf aerator in repeating cycles of up and down motion relative to the ground with the tine(s) carried by the tine holder being punched down into the ground during the down part of each cycle to form an aeration hole and with the tine(s) carried by the tine holder being withdrawn from the ground during the up part of each cycle. The tine(s) used with the tine holder have an upper mounting section. The tine holder of this invention comprises a tine holder having a substantially vertically extending bore. A compressible collar is provided for receiving an upper mounting section of one, tine. The compressible collar has an uncompressed state in which the upper mounting section of the tine can be concentrically inserted into the collar and a fully compressed state in which the upper mounting section of the tine is sufficiently tightly gripped by the collar to prevent removal of the tine from the collar under the forces encountered by the tine and the collar during operation of the aerator. The bore is shaped to compress the collar from the uncompressed state to the fully compressed state as the collar with the tine held therein is slid into the bore in a tine installation operation. A pivotal lever is operatively engaged with both the tine holder and with the collar holding the tine for applying leverage to the collar to force the collar further into the bore to at least finish moving the collar to the fully compressed state within the bore to thereby complete the tine installation operation. 
         [0008]    Another aspect of this invention relates to a tine holder for use with a turf aerator, the tine holder being driven by the turf aerator in repeating cycles of up and down motion relative to the ground with the tine(s) carried by the tine holder being punched down into the ground during the down part of each cycle to form an aeration hole and with the tine(s) carried by the tine holder being withdrawn from the ground during the up part of each cycle. The tine(s) used with the tine holder have an upper mounting section. The tine holder of this invention comprises a tine holder having a plurality of spaced vertical bores therein for holding a plurality of generally upright spaced tines in a side-by-side manner. A plurality of radially compressible members corresponding in number to the numbers of bores is provided with one compressible member being provided for each bore. The compressible members radially expand when the compressible members are uncompressed and radially contract when the compressible members are compressed. Each compressible member when uncompressed is radially large enough to allow the upper mounting section of the tine to be inserted concentrically within the compressible member and each compressible member when compressed is radially small enough to allow the upper mounting section of the tine to be tightly gripped within the compressible member and to avoid coming out of the compressible member during operation of the aerator. Each compressible member can be compressed and uncompressed separately from the other compressible members in the tine holder to allow an individual tine to be removed from and replaced in the tine holder without affecting the gripping force provided by the other compressible members on the other tines. 
         [0009]    Yet another aspect of this invention relates to a tine holder for holding a plurality of aerator tines. The tine holder has a plurality of substantially vertical, tapered bores. Tapered collars are provided with one collar adapted to be received in each bore. Each collar is split so that the collar contracts as the collar is slid into the corresponding bore. The upper end of an aerator tine is inserted into each collar such that the contraction of the collar as the collar is slid into the bore will suffice to tightly grip and hold each tine in the tine holder. A tool is provided for applying leverage to the collar to physically slide the collar in a first direction over final portions of its movement as the collar slides into the bore during tine installation and to physically slide the collar in a second opposed direction over beginning portions of its movement as the collar slides out of the bore during tine removal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    This invention will be described more completely in the following Detailed Description, when taken in conjunction with the following drawings, in which like reference numerals refer to like elements throughout. 
           [0011]      FIG. 1  is a perspective view of a tine holder according to this invention, particularly illustrating three different tines, namely a solid tine, a side eject tine, and a top eject tine, being carried or mounted in the tine holder for use on a turf aerator when the tine holder is mounted on the turf aerator; 
           [0012]      FIG. 2  is a perspective view similar to  FIG. 1 , but with the solid and top eject tines having been removed for the purpose of clarity and with the side eject tine and its carrying collar having been exploded downwardly out of their corresponding bore in the tine holder; 
           [0013]      FIG. 3  is a cross-sectional, side elevational view of the tine holder, collar and side eject tine as shown in  FIG. 2 ; 
           [0014]      FIG. 4  is a perspective view of one of the tine carrying collars used in the tine holder of  FIG. 1 ; 
           [0015]      FIG. 5  is a top plan view of the tine carrying collar shown in  FIG. 4 ; 
           [0016]      FIG. 6  is a front elevational view of the tine carrying collar shown in  FIG. 4 ; 
           [0017]      FIG. 7  is a cross-sectional, side elevational view similar to  FIG. 3  illustrating a portion of the process for installing the tine in the tine holder, namely the step of sliding the upper mounting section of the tine into the collar; 
           [0018]      FIG. 8  is a cross-sectional, side elevation view similar to  FIG. 7 , particularly illustrating another portion of the process for installing the tine in the tine holder, namely the step of sliding the collar and the tine carried thereby partially up into the corresponding bore provided therefor in the tine holder; 
           [0019]      FIG. 9  is a perspective view of a portion of the front face of the tine holder of  FIG. 1 , particularly illustrating the partially inserted collar and tine in the bore as shown in  FIG. 8  to show that the window in the collar straddles the aperture in the tine holder; 
           [0020]      FIG. 10  is a perspective view similar to  FIG. 9 , particularly illustrating a first end of a lever approaching the tine holder and the partially inserted collar 
           [0021]      FIG. 11  is a perspective view similar to  FIG. 10 , but showing the first end of a lever fully engaged with the tine holder; 
           [0022]      FIG. 12  is a side elevational view of the tine holder and the lever corresponding to the depiction in  FIG. 10 , particularly illustrating the curved first cam on the first end of the lever and how the first cam will pivot upwardly as the lever is rotated downwardly from the position shown in  FIG. 12  about the fulcrum provided on the front face of the tine holder; 
           [0023]      FIG. 13  is a perspective view of a portion of the front face of the tine holder of  FIG. 1  with  FIG. 13  being similar to  FIG. 9 , particularly illustrating the top eject tine in a fully inserted position in its bore in the tine holder and with the second end of the lever approaching the tine holder and the collar that carries the top eject tine; 
           [0024]      FIG. 14  is a perspective view similar to  FIG. 13 , particularly illustrating the second end of the lever fully engaged with the tine holder and the collar carrying the top eject tine; 
           [0025]      FIG. 15  is a side elevational view of the tine holder and the lever corresponding to the depiction in  FIG. 12 , particularly illustrating the curved tine removal cam on the second end of the lever and how the tine removal cam will pivot downwardly as the lever is rotated upwardly from the position shown in  FIG. 15  about the fulcrum provided on the front face of the tine holder; and 
           [0026]      FIG. 16  is a perspective view of the lever used to finish installing or to begin removing a collar and the tine carried thereby from one of the bores of the tine holder. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Referring to  FIG. 1 , a tine holder according to this invention is generally illustrated as  2 . Tine holder  2  comprises a generally rectangular body having a top face  4 , a front face  6 , a back face  8 , a bottom face  10 , and a pair of opposed side faces  12 . A vertical flange  14  extends upwardly from the back of top face  4  and includes a plurality of mounting holes  16 . Bolts (not shown) may extend through mounting holes  16  to bolt tine holder  2  to a drive linkage (not shown) on the turf aerator (not shown) which uses tine holder  2 . As the drive linkage reciprocates up and down during the operation of the aerator, tine holder  2  will similarly move up and down to first punch the aeration tines  20  carried by tine holder  2  into the ground and to then lift the aeration tines  20  carried by tine holder  2  out of the ground. The turf aerator to which tine holder  2  is mounted can be of the type further disclosed in the assignee&#39;s U.S. Pat. No. 7,096,969, which is hereby incorporated by reference. 
         [0028]    As shown in  FIG. 1 , tine holder  2  carries or mounts three aeration tines  20  in a side-by-side manner. Thus, as tine holder  2  is vertically reciprocated up and down, each cycle of operation will create three laterally spaced aeration holes in the ground. Typically, the aerator will mount a plurality of side-by-side tine holders thereon and will vertically reciprocate tine holders  2  up and down out of phase with one another. Thus, for example, if an aerator mounts six tine holders to six different drive linkages and if each tine holder mounts or carries three aeration tines  20 , then each up and down cycle of reciprocating motion of the aerator will create eighteen aeration holes across the width of the swath of holes being formed in that pass of the aerator. The number of tine holders  2  mounted to an aerator, and the number of tines  20  mounted or carried on each tine holder, can obviously vary. 
         [0029]    Tine holder  2  of this invention is adapted to mount different types of aerator tines  20 , including the three major types of tines. These types comprise a solid tine  20   a  with a pointed lower section that simply punches an aeration hole into the ground, a hollow side eject tine  20   b  for forming an aeration core in the interior of tine  20  and for ejecting the aeration core through a side eject exit formed by a slot  22 , and a hollow top eject tine  20   c  with an open upper end or top exit in which the aeration core formed in the interior of tine  20  is eventually ejected through the top of tine  20   c . The side eject tine  20   b  is often mounted with the side exit facing to a rear side of tine holder  2  rather than to a right side of tine holder  2  as shown in the drawings. Side eject tine  20   b  is not restricted for use in tine holder  2  with the side exit facing in any particular direction. Usually, the same tine  20 , whether it is a solid tine  20   a , a side eject tine  20   b , or a top eject tine  20   c , will be used on a given tine holder  2 , and on all tine  20  holders  2  on a given aerator, at the same time. The types of tines  20  in use will not typically be mixed as shown in  FIG. 1 , which illustrates different tines simply to show that tine holder  2  may be used with the aforementioned solid  20   a , side eject  20   b , and top eject  20   c  tines. 
         [0030]    Tine holder  2  has identical structure for mounting each tine  20  that it carries, so a description of the structure for one tine  20  will suffice to describe the identical structure for the other tines  20 . In this regard,  FIG. 2  will illustrate the tine mounting structure for only the middle side eject tine  20   b  that had been shown in  FIG. 1 , the other two tines  20   a  and  20   c  having been removed from  FIG. 2  for the purpose of clarity. The other two tines  20   a  and  20   c  will be mounted identically in tine holder  2  using identical mounting structure. This mounting structure is designed to firmly but releasably grip a cylindrical upper mounting section  24  of each tine  20 . 
         [0031]    The tine mounting structure in tine holder  2  for each tine comprises a vertical passageway or bore  26  having an open bottom mouth  28  in bottom face  10  of tine holder  2 . Bore  26  extends through the height of tine holder  2  to an open upper end  30  in top face  4  of tine holder  2 . The reason for extending bore  26  all the way through the height of tine holder  2  is to allow the cores being ejected by a top eject tine  20   c  to pass up through the open upper end of the top eject tine and from there out through the open upper end  30  of bore  26  in tine holder  2 . If tine holder  2  were designed to be used only with solid tines  20   a  or side eject tines  20   b , then bore  26  provided therein would not have to extend all the way through the height of tine holder  2 . The upper end  30  of bore  26  could be closed in that event. 
         [0032]    Referring now to  FIG. 3 , each bore  26  in tine holder  2  has a first portion  32  with a truncated conical shape with the first portion  32  of bore  26  narrowing or tapering inwardly as bore  26  extends upwardly from open bottom mouth  28  thereof. In other words, the diameter of bore  26  is widest at open bottom mouth  28  thereof and then the diameter progressively and slightly decreases as bore  26  extends upwardly over the length of the first portion  32  of bore  26 . Bore  26  then has a shorter second portion  34  of constant diameter atop the first truncated conical portion  32  of bore  26 . A third reduced diameter portion  36  forms the upper end  30  of bore  26 , which third portion may be closed off if tine holder  2  is not designed for top eject tines  20   c  as described earlier herein. 
         [0033]    Bore  26  is designed to coact with and collapse or compress a split collar  40  into which the cylindrical mounting section  24  of tine  20  is inserted as collar  40  and its inserted tine are pushed up into bore  26  through open bottom mouth  28  thereof. The details of collar  40  are best shown in  FIGS. 4-6 . 
         [0034]    Collar  40  is generally cylindrical and extends substantially 360° around in a circle except for a split or gap  42  along one side thereof. Collar  40  does not have a uniform thickness, but preferably comprises a plurality of circumferentially spaced ribs or lands  44  that are relatively thick. Lands  44  are separated by spaced grooves  46  comprised of a wall section that is much thinner than the thickness of the adjacent lands. The presence of split  42  along one side of collar  40  along with the thinner wall sections of grooves  46  make collar  40  compressible under reasonable amounts of force, i.e. collar  40  can be radially squeezed together to radially compress or narrow the inner diameter thereof with the kind of force that can be relatively easily applied using lever  60  as described hereafter. 
         [0035]    The inner diameter of collar  40  is defined by the distance between opposed lands of collar  40 . The inside surfaces of lands  44  extend vertically and are parallel to one another to form a generally cylindrical surface. The inner diameter of this generally cylindrical surface is what changes when collar  40  is compressed. When collar  40  is compressed, the inside surfaces of lands  44  move closer to one another. The upper cylindrical mounting section  24  of tine  20  is inserted up into the inner diameter of collar  40  until the top end of tine  20  abuts against upper overhanging shoulders  48  provided at the tops of lands  44 . This insertion is done when collar  40  is uncompressed since the inner diameter of collar  40  will in that event be slightly larger than the outer diameter of the upper cylindrical mounting section  24  of tine  20 . 
         [0036]    The outside surface of collar  40  is defined generally by the shape of the outside surfaces of lands  44 . As shown in  FIG. 5 , the outside surface of collar  40  also has a truncated, slightly conical shape decreasing in diameter as lands  44  extend vertically upwardly. As mentioned earlier, this shape is designed to allow collar  40  to be inserted into bore  26 . As collar  40  is fully inserted into bore  26 , the shape of bore  26  will then begin to act on the outside surface of collar  40  to compress collar  40  ever more tightly onto the top of tine  20 . When collar  40  is fully received within bore  26 , the gripping force provided by collar  40  will be sufficiently tight to firmly grip and hold tine  20  within tine holder  2  during operation of the aerator, namely while tine  20  is first driven down into the ground and then extracted from the ground in a repetitive manner. 
         [0037]    Collar  40  includes a thickened protruding key  50  containing a tool receiving seat formed by a window  52 . Key  50  is located along the side of collar  40  that is opposite to the side having the split or gap  42  therein. Lands  44  and grooves  46  are absent over key  50  of collar  40 . Key  50  on collar  40  will be received in a mating keyway (not shown) in one side of bore  26  to help locate collar  40  within bore  26  and to prevent relative rotation between collar  30  and bore  26  but to permit up and down sliding motion between the two. Window  52  in the side of collar  40  has a top  54  that forms an upper thrust surface and a bottom  56  that forms a lower thrust surface. 
         [0038]    The operation of installing tine  20  in tine holder  2  will now be described. Referring first to  FIG. 7 , tine  20  is first pushed up into or inserted into collar  40 . In this regard, the upper cylindrical mounting section  24  is simply pushed up into the inner diameter of collar  40  until the top of tine  20  abuts against the overhanging shoulders  48  at the top ends of lands  44 . This is done when collar  40  is not compressed tightly within bore  26  of tine holder  2 . This allows the user to simply push tine  20  by hand into tine holder  2  with there being simply a loose or slight interference fit between the two. 
         [0039]    After tine  20  is inserted into collar  40 , the next step is to push collar  40  up into open bottom mouth  28  of bore  26  in tine holder  2 . The user can do this simply by holding onto tine  20  itself and lifting up on tine  20  while key  50  on collar  40  is aligned with the mating keyway of bore  26 . As collar  40  moves up into bore  26 , partial insertion of collar  40  is permitted before bore  26  starts to begin tightly gripping collar  40 . Thus, the user can push collar  40  up at least partially into bore  26 , again by hand, before sufficient resistance is felt that prevents continued easy insertion by hand. At this point of partial insertion, collar  40  will be partially compressed around tine  20  and both collar  40  and tine  20  will be gripped tightly enough that they will not fall out of bore  26  and tightly enough that it is difficult or impossible to advance them further into bore  26  using simply hand pressure. However, at this point of partial insertion and partial compression of collar  40 , collar  40  and tine  20  are still far from being fully inserted. If the aerator were operated with collar  40  and tine  20  only partially inserted as shown in  FIG. 8 , collar  40  and tine  20  would simply fly or drop out of bore  26  from the forces encountered thereon during operation. 
         [0040]    To completely insert collar  40  and tine  20  into bore  26 , the user must use a lever  60  provided with tine holder  2  of this invention to provide additional upward leverage on collar  40 . Referring first to  FIG. 1 , front face  6  of tine holder  2  is provided with an aperture  62  similar to window  52  in collar  40 . Two fulcrum blocks  64  are provided with one fulcrum block  64  being placed adjacent either side of aperture  62  to define a fulcrum that acts in concert with lever  60 . Since tine holder  2  shown in  FIG. 1  includes three collars  40  for holding three tines  20 , there are three apertures  62  and three pairs of fulcrum blocks  64  provided on front face  6  of tine holder  2 , one aperture  62  and one pair of fulcrum blocks  64  for each tine. 
         [0041]    Referring now to  FIGS. 9-12 , when collar  40  and tine  20  carried by collar  40  are partially inserted into bore  26 , window  52  in collar  40  will straddle aperture  62  in tine holder  2  as shown in  FIG. 9 . The upper thrust surface formed by the top  54  of window  52  in collar  40  will be above the bottom of aperture  62  in tine holder  2  so that the upper half or so of window  52  in collar  40  will be exposed through aperture  62  in tine holder  2 . A first end of elongated lever  60  is formed with a first curved cam  70  that is adapted to be inserted through aperture  62  in tine holder  2  with first cam  70  being able to get under the top of window  52  in collar  40 . The first end of lever  60  also has a plurality of bearing surfaces  72  with one bearing surface  72  being adjacent either side of first cam  70 . Bearing surfaces  72  engage or abut with the top sides of fulcrum blocks  64  when the first end of lever  60  is inserted as described above. 
         [0042]      FIG. 10  shows the first end of lever  60  approaching window  52  in tine holder  2  and collar  40 , but with the first end of lever  60  not yet engaged with either.  FIG. 11  shows the first end of lever  60  having engaged tine holder  2  with first cam  70  having been at least partially inserted or jammed beneath the top of window  52  in collar  40  and with the bearing surfaces  72  on the first end of lever  60  having been abutted against the top sides of fulcrum blocks  64 . 
         [0043]    With lever  60  inserted into tine holder  2  as described above and with lever  60  inclined downwardly, the user can complete the tine installation operation on the partially inserted collar and tine by pushing downwardly on the second end of lever  60  as indicated by the arrow A in  FIG. 12 . When this occurs, the first end of lever  60  will pivot about the fulcrum provided by fulcrum blocks  64  and first cam  70  on the first end of lever  60  will pivot upwardly as indicated by the arrow B in  FIG. 12 . Since first cam  70  on the first end of lever  60  is beneath the top of window  52  and bears against the upper thrust surface formed by the top of window  52  in collar  40 , this pivoting motion in the direction of the arrow B will further force or raise collar  40  and tine  20  into a fully inserted position in tine holder  2 . Essentially, lever  60  provides the user with enough leverage to fully raise collar  40  and tine  20  into place where collar  40  is very tightly compressed around tine  20 , namely so tightly that tine  20  will be held in place during operation of the aerator and during the usual and normal forces encountered by tine  20  as it is driven into the ground and extracted therefrom. When collar  40  and tine  20  are fully inserted, window  52  in collar  40  will be generally vertically aligned with aperture  62  in tine holder  2 . 
         [0044]    Since lever  60  is needed to fully insert collar  40  and tine  20  into tine holder  2  with hand pressure being insufficient to do the job, it is apparent that some leverage must also be applied to do the reverse, namely to remove or uninstall collar  40  and tine  20  from tine holder  2 . This removal operation will be illustrated in conjunction with  FIGS. 13-15 . These figures illustrate lever  60  being used to remove collar  40  holding the top eject tine  20   c  from tine holder  2 . In  FIG. 15 , the middle side eject tine  20   b  is shown in its partially installed or inserted position prior to full insertion as shown in  FIGS. 9-12 . However,  FIG. 15  shows the top eject tine  20   c  fully installed. 
         [0045]    Lever  60  also has a second end that is formed a bit differently than the first end. The second end of lever  60  also has a curved second cam  80 , though one curved in a different manner than first cam  70  on the first end of lever  60 , along with a pair of bearing surfaces  82  that will abut under fulcrum blocks  64  on tine holder  2  during a tine removal operation.  FIG. 13  shows the second end of lever  60  approaching aperture  62  in tine holder  2  that is adjacent the top eject tine  20   c . Note that since the top eject tine  20   c  is fully inserted into the corresponding bore in tine holder  2 , aperture  62  in tine holder  2  is shown in  FIG. 13  aligned with or overlying window  52  in collar  40 . 
         [0046]      FIG. 14  shows the second end of lever  60  engaged with tine holder  2 . In this regard, second cam  80  on the second end of lever  60  has been inserted through aperture  62  in tine holder  2  and into window  52  in collar  40  that holds the top of the top eject tine  20   c . Bearing surfaces  82  are engaged or jammed up against the underside of fulcrum blocks  64 . 
         [0047]    Referring to  FIG. 15 , when lever  60  is rotated upwardly as shown by the direction of the arrow C in  FIG. 15 , second cam  80  on the second end of lever  60  is rotated downwardly as shown by the arrow D in  FIG. 15 . This pushes downwardly on the lower thrust surface formed by the bottom  56  of window  52  in collar  40  to force or lever collar  40  and tine  20  carried thereby in a downward direction out of bore  26 . The user can continue to use lever  60  to force collar  40  and tine  20  downwardly until collar  40  becomes sufficiently loose within bore  26  to permit collar  40  to be gripped and completely removed using hand pressure. Thus, the same tool that is used to install collar  40  and tine  20  in a bore in tine holder  2  is also used to remove collar  40  and tine  20  from a bore in tine holder  2 . 
         [0048]    Either end of lever  60  and either the first cam  70  or second cam  80  can be used for both a tine installation and tine removal operation. It is not necessary to use one end of lever  60  for the tine installation operation and the other end of lever  60  for the tine removal operation. In using the same end of lever  60  for both operations, lever  60  will be flipped over or inverted from one operation to the next since cams  70  or  80  point in opposite directions in the two operations and bearing surfaces  72  or  82  abut or engage on opposite sides of the fulcrum blocks  64 . For example, in a tine removal operation, cams  70  or  80  will have the pointed nose thereof facing upwardly with bearing surfaces  72  or  82  resting on the top sides of fulcrum blocks  64 . In a tine removal operation, the reverse is true—cams  70  or  80  will have the pointed nose thereof facing downwardly with bearing surfaces  72  or  82  engaging against the bottom sides of fulcrum blocks  64 . 
         [0049]    The reason for having two differently shaped cams  70  or  80  on opposite sides of lever  60  is to give the user some choice and flexibility in engaging lever  60  within collar  40  given the different relative positions in which different tine holders  2  come to rest when aerator  4  is not operating given the out of phase cyclic reciprocation of tine holders  2 . Some tine holders  2  might be at or near top dead center, other tine holders  2  might be at or near bottom dead center, and yet other tine holders  2  might be somewhere in between top and bottom dead center. Tine holders  2  located at or near top dead center are harder to reach in at least one aerator  4  using tine holders  2  than the other tine holders  2 . If the user needs to remove and replace a tine in one of the tine holders  2  at or near top dead center, the user might have to try first one end of lever  60 , and then the other end of lever  60 , and might also have to incline lever  60  upwardly, to find the end and orientation of lever  60  that works best in permitting lever  60  to properly engage collar  40  of the tine in question. For removing tines in other lower tine holders  2 , i.e. those at bottom dead center or in intermediate positions, the opposite end of lever  60  and other orientations of lever  60  (such as an initially downwardly inclined orientation) might well work better. 
         [0050]    Tine holder  2  of this invention permits the quick and easy installation or removal of an individual tine from tine holder  2  without requiring that tine holder  2  be disassembled to release tine  20  from some type of clamping engagement. This is an advantage because it speeds the replacement of an individual tine that might be bent or broken without the user having to unbolt various parts of tine holder  2  or unbolt any parts for that matter. 
         [0051]    Moreover, the act of installing or removing any tine is quick and easy. To install, tine  20  is slipped into a collar, collar  40  and tine  20  are partially inserted into one bore  26  in tine holder  2  as far as hand pressure will permit, and then the first end of lever  60  is engaged with tine holder  2  and collar  40  and a simple downward pivoting motion on lever  60  will force collar  40  and tine  20  into their fully inserted position within bore  26 . In this position, tine  20  is tightly gripped within compressible collar  40  and the gripping engagement will be sufficient to hold tine  20  in place during operation of the aerator. 
         [0052]    The process of removing tine  20  is the reverse of that described above. In other words, the other end of lever  60  is engaged with tine holder  2  and collar  40  and lever  60  is pivoted upwardly to force collar  40  and tine  20  downwardly relative to bore  26 . If desired, collar  40  and tine  20  can then be removed by hand after lever  60  has sufficiently loosened them within bore  26  or lever  60  could be used to completely force collar  40  out of bore  26 . After removal tine  20  can simply be slipped out of collar  40 . Thus, very little time and effort is needed either to install or remove a tine from tine holder  2 . 
         [0053]    Various modifications of this invention will be apparent to those skilled in the art. The presence of lands  44  and grooves  46  on collar  40  is preferred. They decrease the amount of force or leverage the user must apply to install or remove a tine  2 . However, lands  44  and grooves  45  could be removed if so desired. Accordingly, this invention shall be limited only by the appended claims.