referring now to the drawings more specifically and to fig1 in particular , a seed planting unit 20 is shown . seed planting unit 20 is part of a seed planting implement having a frame that includes a tow bar assembly , a tow bar and a connection assembly at the longitudinally forward end thereof configured for mating with a corresponding hitch of a tractor or other work vehicle ( all of which are not shown ) for pulling the seed planting implement through a field . a laterally extending toolbar 18 ( shown in dashed lines in fig2 ) is generally transverse to the tow bar and thereby generally transverse to the direction 28 the implement is towed during planting operations . a plurality of seed planting units ( or row units ) 20 are connected to toolbar 18 in a side by side relationship , each of the seed planting units ( row units ) being substantially identical to the others . in the exemplary embodiment shown , a seed planting implement may include sixteen seed planting units 20 , only one of which is identified with reference numbers ; however , it should be understood that more or fewer seed planting units can be provided on a particular seed planting implement . referring now primarily to fig1 and 2 , each seed planting unit 20 includes a frame 22 that is connected to toolbar 18 by upper arms 24 and lower arms 26 , each arm 24 , 26 being connected to frame 22 and to toolbar 18 . accordingly , each seed planting unit 20 extends rearward from toolbar 18 to plant a row of seeds as the seed planting implement is towed across a field in the direction 28 . the individual planting units 20 are spaced along toolbar 18 to provide planted seed rows of a desired spacing . during a planting operation , forward movement of the seed planting implement causes each seed planting unit 20 to form a seed trench , deposit equally spaced seeds in the seed trench and close the seed trench over the deposited seeds . each seed planting unit 20 includes a ground penetrating or seed trench opening assembly having a pair of forwardly and downwardly angled opening discs 32 that converge forwardly and downwardly to open a furrow or seed trench as the seed planting implement moves forward . as particularly seen in fig2 , the opening disks 32 are mounted on axes a 1 and a 2 , in staggered relation so that their axes are spaced by dl . opening disks 32 are removably retained on frame 22 by nuts 33 . a seed metering system receives seeds from a seed hopper and provides individual seeds at a controlled rate to a seed tube 38 ( shown in dashed lines ) for deposit in the bottom of the seed trench formed . the details of the seed metering system are not shown to enable a clearer understanding of the present invention . a seed trench closing mechanism 50 ( fig1 ) at the trailing end of each seed planting unit 20 closes the seed trench after the seeds have been deposited in the seed trench . seed trench closing mechanism 50 includes a pair of pinch wheels 52 ( fig2 ) that operate on opposite sides of the seed trench to move soil back into the seed trench and over the seeds deposited in the bottom of the seed trench . a trailing press wheel ( not shown ) travels along the top of the closed seed trench and firms the soil replaced in the seed trench . the depth to which opening discs 32 are allowed to penetrate the ground is controlled by a depth control assembly 60 that includes a pair of gauge wheels 62 , gauge wheel arms 64 and a depth adjuster and linkage assembly 80 . one of the gauge wheels 62 is provided adjacent each opening disc 32 . each gauge wheel 62 is rotatably mounted on one of the gauge wheel arms 64 by a wheel retention shaft 68 , which is particularly illustrated in fig2 where the near side gauge wheel 62 has been removed . the gauge wheel arms 64 are of equal length for production purposes and are pivotally connected at a pivotal attachment 66 to seed planting unit frame 22 . pivoting gauge wheel arm 64 about pivotal attachment 66 to frame 22 changes the relative height position of gauge wheel 62 . a forming point assembly 100 is positioned between opening disks 32 and defines the contour of the bottom of the trench formed by the seed planting unit 20 . as shown in fig2 and 3 , the forming point assembly 100 is positioned between disks 32 . the disks 32 deflect during operation and can abut and rub on the forming point assembly , causing wear since the interaction is steel to steel . in accordance with the present invention , a wearable insert is positioned between the forming point assembly 100 and the disks 32 , as described below . referring specifically to fig3 and 4 , the forming point assembly 100 has a base 102 that has an opening 104 providing a mounting point to frame 22 . a wall section 108 is usually formed from sheet metal and has a curved leading edge connected to the downstream side of base 102 and which gives width to the trench so formed . base 102 has a leading edge 106 which is wedge shape when viewed in the plan view of fig3 and circular in shape when viewed from the side . base 102 has a circular opening 112 with a flat section 114 interposed in its periphery , as illustrated in fig6 . a wearable insert 116 having a cylindrical shape and a flat 118 fits into opening 112 , as shown in fig4 , and it is slidable laterally relative to base 102 . as shown particularly in fig3 , the insert 116 extends beyond the base 102 and into abutment with the inside of opposed disks 32 . insert 116 is slidable laterally , but is not rotatable . in operation of the seeding unit 20 , the disks 32 deflect inward as they form the desired trench . instead of abutting the forming point assembly 100 the opening disks 32 abut the wear insert 116 , which acts as a sacrificial element protecting the remaining components . because the insert 116 is movable laterally it balances between the two disks 32 . when the insert 116 reaches its wear limit it may be easily removed by disconnecting one or both of the disks 32 by removing nuts 33 . at that point , the wear insert 116 may be simply replaced by pushing it out of the hole 112 and inserting a new wear insert 116 . the wear insert can be formed from any wearable plastic material such as uhmw plastic and nylon thus avoiding the replacement of more expensive steel parts in the disks 32 and forming point assembly 100 . while the wear insert 116 in fig2 and 3 is shown as cylindrical with a flat , it may be in another form as illustrated in fig5 . in that figure , the base 102 has a modified wall section 108 ′ secured to it . a rectangular opening 120 is provided in the forward edge of the wall section 108 ′ and cooperates with the base 102 to form a rectangular through opening 120 which receives a rectangular shaped wear insert 122 . in this case , the wear insert 122 may slide laterally but does not have the possibility to rotate . the configuration shown in fig5 has the same benefits as the wear insert 116 of fig2 and 3 . while this invention has been described with respect to at least one embodiment , the present invention can be further modified within the spirit and scope of this disclosure . this application is therefore intended to cover any variations , uses , or adaptations of the invention using its general principles . further , this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims .
an agricultural seed planting implement has a frame moveable in an up and down direction relative to soil over which the frame traverses . a seed trench opening assembly mounted on the frame includes disks mounted side by side and having a forming point positioned in between . a wearable insert of plastic is slidably but non - rotatably retained in the forming point to abut the disks when they are deflected . the disks are removable to enable simple replacement of the wearable insert .