Patent Publication Number: US-7721814-B2

Title: Method and apparatus for harvesting and picking up sod

Description:
PRIOR APPLICATION 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/649,639, filed Feb. 4, 2005 entitled “METHOD AND APPARATUS FOR HARVESTING AND PICKING UP SOD”; U.S. Provisional Application Ser. No. 60/663,246 filed Mar. 21, 2005 entitled “METHOD AND APPARATUS FOR HARVESTING AND PICKING UP SOD”; U.S. Provisional Application Ser. No. 60/715,135 filed Sep. 9, 2005 entitled “METHOD AND APPARATUS FOR HARVESTING AND PICKING UP SOD”; and U.S. Provisional Application Ser. No. 60/758,195 filed Jan. 12, 2006 entitled “METHOD AND APPARATUS FOR HARVESTING AND PICKING UP SOD”. 

   FIELD OF THE INVENTION 
   This invention relates to a sod harvester which, after harvesting sod, can pick up the cut sod and stack it, and to methods relating to sod harvesting. 
   BACKGROUND OF THE INVENTION 
   Sod harvesters for cutting a strip of sod from the ground and for stacking the sod as a set of slabs on a receiving surface (typically a pallet) have existed for many years. However, prior harvesters which have included a mechanism for automatically stacking slabs of sod on a pallet have been extremely complex and costly. One problem has been that since the strip of sod is normally cut and delivered continuously from the ground, a buffer storage must be provided on the sod harvester to receive sod which continues to be delivered from the cutting knife at the same time when sod which has previously been cut is to be picked up and stacked or moved to another location. The provision of buffer storage for the sod until it can be picked up has in the past added to the size, cost and complexity of the harvester. 
   BRIEF SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention, in one of its aspects, to provide a method and apparatus for handling sod in a harvester which cuts a continuous strip of sod, such that the complexity of providing a separate buffer storage for newly cut sod while previously cut sod is being picked up, is reduced. In one aspect the present invention provides a sod harvester adapted for travel along a path of travel and comprising: 
   a) a sod cutting knife for cutting pieces of sod from the ground, each piece having a leading edge and a trailing edge, 
   b) a conveyor mechanism for carrying sod away from said cutting knife to a first location, 
   c) a sod pick-up mechanism for picking up sod from said first location and for moving such sod to a second location and for then returning to said first location to again pick up sod at said first location, 
   d) said conveyor mechanism including a plurality of conveyors in sequence including a first conveyor for receiving a sod piece from said cutting knife and a second conveyor for receiving and accelerating said sod piece toward said first location to create a time period between the passage of the trailing edge of one sod piece and the arrival of the leading edge of the following sod piece, 
   e) said conveyor mechanism further including a mechanism for supporting a said sod piece in a stopped condition at said first location, while a following sod piece is moving towards said first location, 
   f) said time period being sufficient for a said sod piece to assume said stopped condition at said first location and for said sod pick-up mechanism to pick up and remove the stopped sod piece from said first location before the following sod piece arrives at said first location. 
   In another aspect the present invention provides a method of harvesting sod comprising: 
   a) continuously cutting pieces of sod, each piece having a leading edge and a trailing edge, 
   b) conveying said pieces of sod sequentially to a first location, 
   c) while performing said conveying, accelerating each sod piece away from the sod piece behind it to create a time interval between the passage of the trailing edge of one sod piece and the leading edge of the next sod piece, 
   d) stopping a sod piece at said first location and while said sod piece is stopped, picking up said sod piece and then moving such sod piece to a second location, 
   e) the steps of stopping and picking up said sod piece being performed in said time interval. 
   Further objects and aspects of the invention will appear from the accompanying disclosure, taken together with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  is a perspective view of a sod harvester according to the invention; 
       FIG. 2  is a diagrammatic side view of a portion of the sod harvester of  FIG. 1 ; 
       FIG. 3  is a top view of sod cutting knives and rollers for the  FIG. 1  harvester; 
       FIG. 4A  is a perspective view of conveyors for the  FIG. 1  sod harvester, with sod advancing up the first set of conveyors; 
       FIG. 4B  is a perspective view of the middle conveyor from the third set of conveyors of the  FIG. 1  sod harvester; 
       FIG. 4C  is a perspective view similar to that of  FIG. 4A  but showing sod located on the first and second sets of conveyors; 
       FIG. 4D  is a view similar to that of  FIG. 4C  but showing sod advancing up the first and second sets of conveyors and with sod also located on the third set of conveyors; 
       FIG. 5  is a diagrammatic view of a sensor for the  FIG. 1  sod harvester; 
       FIG. 6  is a simplified perspective view showing a gantry and a sod carrier for the  FIG. 1  sod harvester; 
       FIG. 7  is a top view of the gantry and sod carrier of  FIG. 6 ; 
       FIG. 8A  is another perspective view of the gantry and sod carrier of the  FIG. 1  harvester, in place over the third conveyor set and over a pallet; 
       FIG. 8B  is a view similar to that of  FIG. 8A  but showing sod located on the pallet, having been deposited there by the sod carrier; 
       FIG. 9A  is a top view showing portions of the gantry and sod carrier of  FIG. 6 ; 
       FIG. 9B  is a top view similar to that of  FIG. 9A  but showing the sod carrier located over the pallet and rotated 90° from the position of  FIG. 9A ; 
       FIG. 9C  is a view similar to that of  FIG. 9A  but showing sod on the pallet in the position in which it was deposited by the sod carrier from the  FIG. 9B  orientation; 
       FIG. 10  is a diagrammatic view of sensors, a computer and a hydraulic circuit for the  FIG. 1  sod harvester; 
       FIG. 11  is a perspective view of a portion of a clamp on the sod carrier of the  FIG. 1  harvester; 
       FIG. 12  is a front view of a pallet containing layers of sod placed by the  FIG. 1  harvester; 
       FIG. 13  is a rear perspective view of a portion of the  FIG. 1  sod harvester, showing details of the forklift and pallet; 
       FIG. 14  is a perspective view showing further detail of the forklift of the  FIG. 1  sod harvester; 
       FIG. 15  is a simplified perspective view showing portions of the forklift of the  FIG. 1  sod harvester with an electric eye level adjusting mechanism; 
       FIG. 16  is a side view showing a rear roller arrangement for the  FIG. 1  sod harvester; 
       FIG. 17  is a diagrammatic view of another embodiment of the harvester according to the invention, mounted on the side of a tractor; 
       FIG. 18  is a side view of the tractor and harvester of  FIG. 17 ; 
       FIG. 19  is a top view of a sod layer stacked on a pallet according to an aspect of the invention; 
       FIG. 20  is an edge view of the sod stack of  FIG. 19 ; 
       FIG. 21  is a perspective view of the sod stack of  FIGS. 19 and 20 ; 
       FIG. 22  is a top view of another set of sod layers stacked on a pallet; 
       FIG. 23  is an edge view of the sod stack of  FIG. 22 ; 
       FIG. 24  is a perspective view of the sod stack of  FIGS. 22 and 23 ; 
       FIG. 25  is a top view showing sod on a pallet on forks having a scissors connection to the forklift mast; 
       FIG. 26  is a side view of the arrangement of  FIG. 25 ; 
       FIG. 27  is a top view similar to that of  FIG. 25  but with the scissors extended; 
       FIG. 28  is a side view of the  FIG. 27  arrangement; 
       FIG. 29  is a perspective view of the  FIG. 25  arrangement; 
       FIG. 30  is a perspective view of a sod slab and knives for cutting the sod slab into a number of pieces; 
       FIG. 31A  is a top view of a pallet injector for supplying a pallet to the forklift of the  FIG. 1  harvester, and also showing the forklift, in idle condition; 
       FIG. 31B  is a side view of the  FIG. 31A  arrangement; 
       FIG. 31C  is a perspective view of the  FIG. 31A  arrangement; 
       FIG. 32A  is a top view similar to  FIG. 31A  and showing the pallet dispenser pulled back; 
       FIG. 32B  is a side view of the  FIG. 31A  arrangement; 
       FIG. 32C  is a perspective view of the  FIG. 32A  arrangement; 
       FIG. 33A  is a top view of the  FIG. 31A  arrangement, with the pallet dispenser having pushed a pallet over the forks; 
       FIG. 33B  is a side view of the  FIG. 33A  arrangement; 
       FIG. 33C  is a perspective view of the  FIG. 33A  arrangement; 
       FIG. 34A  is a top view of the  FIG. 31A  arrangement, with a pallet supported by the pallet injector over the forks and sod stacked thereon; 
       FIG. 34B  is a side view of the  FIG. 34A  arrangement; 
       FIG. 34C  is a perspective view of the  FIG. 34A  arrangement; 
       FIG. 35A  is a top view of the  FIG. 31A  arrangement, with the pallet now supported by the forklift forks; 
       FIG. 35B  is a side view of the  FIG. 35A  arrangement; 
       FIG. 35C  is a perspective view of the  FIG. 35A  arrangement; 
       FIG. 36A  is a top view of the  FIG. 31A  arrangement, with the pallet dispenser pulled back and the pallet on the forks loaded with sod and in a lowered position; 
       FIG. 36B  is a side view of the  FIG. 36A  arrangement; 
       FIG. 36C  is a perspective view of the  FIG. 36A  arrangement; 
       FIG. 37A  is a top view of the  FIG. 31A  arrangement, with the pallet injector having pushed a new pallet over the forks for loading, and with a loaded pallet still on the forks; 
       FIG. 37B  is a side view of the  FIG. 37A  arrangement; 
       FIG. 37C  is a perspective view of the  FIG. 37A  arrangement; 
       FIG. 38  is a plan view of cut slabs of sod on a pallet, and showing each layer rotated by a few degrees with respect to the layer below it; 
       FIG. 39  is a perspective view of the sod layers of  FIG. 38 ; 
       FIG. 40  is an end view of a piling cavity for stacking sod slabs, dimensioned to produce curled up edges for the sod and to produce overlap in successive layers of sod; 
       FIG. 41  is a perspective view of a stack of sod on a pallet and having curled up edges; 
       FIG. 42A  is an end view of a pallet having a concave upper surface; 
       FIG. 42B  is a perspective view of the  FIG. 42A  pallet; 
       FIG. 43A  is an end view of a modified pallet having a concave upper surface; 
       FIG. 43B  is a perspective view of the  FIG. 43A  pallet; 
       FIG. 44A  is an end view of a further modified pallet having a concave upper surface; 
       FIG. 44B  is a perspective view of the  FIG. 44A  pallet; 
       FIG. 45A  is an end view of a still further modified pallet having a concave upper surface; 
       FIG. 45B  is a perspective view of the  FIG. 45A  pallet; 
       FIG. 46A  is an end view of yet another modified pallet having a concave upper surface; 
       FIG. 46B  is a perspective view of the  FIG. 46A  pallet; 
       FIG. 47A  is an end view of another modified pallet having a concave upper surface; 
       FIG. 47B  is a perspective view of the  FIG. 47A  pallet; 
       FIG. 48  is an end view of the  FIG. 47A ,  FIG. 47B  pallet with sod stacked thereon; 
       FIG. 49  is a perspective view of an elongated sod slab and a cutting knife for partially severing two portions of the sod slab; 
       FIGS. 50A to 50E  inclusive are side views of different versions of a cross-cut knife for partially severing an elongated sod slab into two partially connected sod slabs; 
       FIG. 51  is a top diagrammatic view of a portion of a harvester and showing three sod cutting heads mounted on the harvester for powered sideways movement of two of the heads; 
       FIG. 52  is a perspective view of the front of the harvester showing a set of three cross-cut knives, each separately pivoted, for cross-cutting a wide strip of sod; 
       FIG. 53  is a front view of the cross-cut knives of  FIG. 52 ; 
       FIG. 54  is a diagrammatic side view of third set conveyors and the sod pick-up mechanism illustrating another aspect of the invention; 
       FIG. 55  is a diagrammatic perspective view of the apparatus of  FIG. 54 ; and 
       FIG. 56  is a diagrammatic perspective view of a modification of the apparatus of  FIG. 55 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
   Reference is first made to  FIG. 1 , which shows a simplified diagrammatic view of a sod harvester  10  according to the invention. The sod harvester  10  is intended to be pulled by a towing vehicle, e.g. a tractor (not shown), but it will be appreciated that a sod harvester according to the invention can be self-propelled, or it can be mounted directly on the side of a tractor, as is well known in the field. 
   The harvester  10  is intended to cut slabs of sod and to stack the slabs in flat condition on a pallet, as contrasted with sod harvesters which produce rolls of sod. Preferably, the sod harvester  10  cuts side-by-side strips of sod of sufficient total width to constitute an entire single layer on the pallet, so as to simplify stacking the cut slabs of sod on the pallet (as will be explained). Typically, therefore, the harvester  10  may have three vibrating sod cutting knives  12 - 1 ,  12 - 2 ,  12 - 3  (best shown in  FIG. 3 ) which undercut and side cut three side-by-side strips of sod  14 - 1 ,  14 - 2 ,  14 - 3  ( FIG. 4A ). Rollers  16 - 1 ,  16 - 2 ,  16 - 3  ( FIG. 3 ) ahead of the cutting knives roll the sod before the sod is cut, and vertically moving cross-cut knives  18 - 1 ,  18 - 2 ,  18 - 3  positioned ahead of the rollers are driven into the ground at desired intervals to cut the strips of sod into lengths (i.e. into pieces or slabs of soil). Conventional fingers  20 - 1 ,  20 - 2 ,  20 - 3  attached to and extending rearwardly from the cutting knives guide the cut sod onto conveyors (to be described) of the sod harvester. Conventional means, not shown, are provided to lift the cutting knives and rollers above the ground when they are not being used for cutting, so that the harvester  10  can travel. 
   The vibrating sod cutting knives, rollers, cross-cut knives and fingers have all been well-known in the industry for many years and are shown, for example, in U.S. Pat. No. 3,509,944 issued May 5, 1970. 
   It is desirable that the three strips of sod  14 - 1 ,  14 - 2 ,  14 - 3  cut by harvester  10  be located closely adjacent each other from a side-by-side perspective, with minimal lateral gaps between them, so as not to leave narrow uncut (and wasted) strips of sod in the field being cut. Therefore, preferably the center sod cutting knife  12 - 2  and its associated roller  16 - 2  and cross-cut knife  18 - 2  are offset forwardly of the two outer sod cutting knives and rollers, as shown in  FIG. 3 . With this arrangement, the two outer knives and their associated mechanisms can be moved laterally inwardly toward the center sod cutting knife  12 - 2  to minimize or to reduce to zero any gaps between adjacent sod strips. (In some sod growing areas, where after harvesting sod is regrown from pieces of sod left in the field, then very narrow “ribbons” of uncut sod may be left between adjacent cut strips, to assist in regrowth of new sod after harvesting.) 
   In a typical harvester version, the center sod cutting knife  12 - 2  may be located, e.g. eight inches in front of the two outer sod cutting knives  12 - 1 ,  12 - 3 , but this distance can be varied and different offset patterns can be used if desired. In the version shown in  FIG. 3 , the fingers  20 - 2  extending rearwardly from the center sod cutting knife  12 - 2  are longer than the fingers  20 - 1 ,  20 - 3  of the two outer knives, to guide the cut sod onto the conveyors described below. 
   As best shown in  FIGS. 4A to 4D , the harvester  10  includes three sequential sets of conveyors  30 ,  32 ,  34  to move the cut sod pieces from the cutting knives rearwardly to a location from which the cut sod pieces can be picked up and transferred to a pallet or other desired support. 
   The first set of conveyors  30  includes two side-by-side conveyors  30 - 1 ,  30 - 2  driven at slightly greater than ground speed (ground speed being the speed at which the machine travels over the ground) by a hydraulic motor diagrammatically indicated at  33 . The first set of conveyors  30  can consist of a single conveyor, or it can consist of three or four side-by-side conveyors (any number can be used), but two side-by-side conveyors  30 - 1 ,  30 - 2  have been found convenient from a production viewpoint. The conveyors  30 - 1 ,  30 - 2  both operate at the same speed, and since they carry the cut sod upwardly at a relatively steep angle, elongated fingers  35 , pivotably mounted on a bridge  36  extending across the conveyors  30 - 1 ,  30 - 2 , are positioned to lie against the cut sod strips as the sod travels upwardly, to reduce slippage of the sod on the conveyors  30 - 1 ,  30 - 2  and to prevent the leading edges of the cut sod strip from curling back downhill. As is well-known in the industry, the speed of hydraulic motor  33  is controlled by a hydraulic circuit (indicated at  145  in  FIG. 10 ) which reads ground speed from a conventional sensor  200 . 
   The second set of conveyors  32  also consist of two side-by-side conveyors  32 - 1 ,  32 - 2  (although again, any desired number can be used). Again, elongated fingers  38  are provided, pivotably mounted on a bridge  40  extending across the second set of conveyors  32 , to overlie the sod strips as they travel up the second conveyor set  32 , again to reduce slippage of the sod on the second conveyors and to prevent the leading edges of the sod strips from curling back. The second set of conveyors are driven in unison by a hydraulic motor diagrammatically indicated at  42 , preferably at approximately twice ground speed. Thus, when the sod strips  14 - 1  to  14 - 3  reach the second set of conveyors  32 , as shown in  FIG. 4C , the sod strips will be accelerated away from the sod strips on the first set of conveyors  30 , leaving a gap indicated at  44  in  FIG. 4C , for a reason to be described. 
   From the second set of conveyors  32 , the three side-by-side sod strips  14 - 1 ,  14 - 2 ,  14 - 3  next travel onto the third conveyor set  34 , which consists of three side-by-side conveyors  34 - 1 ,  34 - 2 ,  34 - 3 , one to accommodate each sod strip. In a preferred embodiment, the outer third conveyors  34 - 1 ,  34 - 3  are each divided into two sub-conveyors  34 - 1   a ,  34 - 1   b  and  34 - 3   a ,  34 - 3   b . The sub-conveyors of each side conveyor  34 - 1 ,  34 - 3  are linked by a chain and sprocket mechanism  46  ( FIG. 1 ) so that only one of the two sub-conveyors need be driven to drive both sub-conveyors of an outer conveyor. The division of each side third set conveyor  34 - 1 ,  34 - 3  into two sub-conveyors provides a gap or depression  48 - 1 ,  48 - 3  in the center of the top rear of these conveyors, to accommodate a cross-cut knife as will be explained. 
   Since there may not be space to divide the center third set conveyor  34 - 2  into two sub-conveyors, the center third set conveyor  34 - 2 , as shown in  FIG. 4B , has a center depression  50  provided by three rollers  52 , to accommodate a cross-cut blade if a cross-cut is needed. 
   Each third set conveyor  34 - 1 ,  34 - 2 ,  34 - 3  is driven separately by a hydraulic motor  60 - 1 ,  60 - 2 ,  60 - 3 . All three third set conveyors  34 - 1 ,  34 - 2 ,  34 - 3  preferably operate at approximately three times ground speed, thus accelerating the sod strips away from the sod strips following behind them on the second set conveyors  32  and producing a gap  62  ( FIG. 4D ) between the trailing edges of the sod strips on the third set conveyors and the leading edges of the sod strips on the second set conveyors. The gap  62  is typically larger than the gap  44 . 
   In the operation of the sod harvester  10  as so far described, the three strips of sod  14 - 1  to  14 - 3  are cut by cutting knives  12 - 1  to  12 - 3  and cross-cut knives  18 - 1  to  18 - 3  and travel up the first and second conveyor sets  30 ,  32  as shown in  FIGS. 4A and 4C . Since the center cutting knife  12 - 2  and cross-cut knife  18 - 2  are positioned ahead of the two side knives, the center sod strip  14 - 2  will be cut and released from the ground first and therefore its leading edge  64 - 2  on first conveyor set  30  will be ahead of (i.e. offset from) the leading edges  64 - 1 ,  64 - 3  of the two side sod strips  14 - 1 ,  14 - 3  (see  FIG. 4A ). This offset of leading edge  64 - 2  continues on the second set conveyors  32  (see  FIG. 4D ). 
   When the sod strips  14 - 1  to  14 - 3  reach the third set conveyors  34 , they are accelerated onto those conveyors until their respective trailing edges  66 - 1 ,  66 - 2 ,  66 - 3  pass individual sensors  70  ( FIG. 5 ) for each third set conveyor. The sensors  70  each consist of a tongue  72  which rests on its associated third set conveyor and is attached at rotary connection  74  to a microswitch  76 . When a sod strip on a third set conveyor  34 - 1 ,  34 - 2  or  34 - 3  passes out from under the tongue  72 , the tongue  72  drops slightly (by the thickness of the sod strip), operating the microswitch  76 . The three microswitches  76  are connected to a computer (to be discussed) which then shuts off the third set conveyor  34 - 1 ,  34 - 2  or  34 - 3  in question until the start of the next cycle (as will be described). The result of this individual control of the third set conveyors  34  is that all three strips of sod  14 - 1  to  14 - 3  are automatically positioned on the third set conveyors  34  with their leading edges aligned (and therefore also with their trailing edges aligned), as shown in  FIG. 4D  (even though previously the leading edge  64 - 2  of the center sod strip  14 - 2  was ahead of the other two leading edges). 
   The third set conveyors  34  acts as a storage or buffer set of conveyors, providing a location from which the sod strips can be picked up and transferred to a pallet. The gap  62  between the leading edges of the sod strips advancing up the second conveyor set  32 , and the trailing edges of the sod strips located on the third conveyor set  34 , provides a time period or time interval during which the sod strips on the third conveyor set  34  can be picked up and transferred to a pallet or other stacking location (or at least can be picked up and moved away from the third conveyor set) before the next set of sod strips arrives at the third conveyor set. 
   A preferred mechanism for picking up the sod strips, moving them over a pallet, and depositing them on the pallet will next be described with reference to  FIG. 6  and following. As there shown, the harvester  10  has a sod pick-up and transfer mechanism  80 . Mechanism  80  includes a gantry arrangement which comprises a guide frame  82  fixedly mounted on the harvester  10 , and a gantry  84  mounted on the guide frame  82  by wheels  86  (one at each corner of the gantry) so that the gantry can roll back and forth in a side-to-side direction on the frame  82 , with the wheels  86  supported and guided in channels  88  at the sides of the guide frame  82 . 
   The guide frame  82  extends over the third set conveyors  34  and also extends over a pallet  90  ( FIG. 8A ) supported on a forklift  92  located at one side of the third set conveyors  34 . A sod carrier  94  is suspended from the gantry  84  and serves to pick-up the sod from the third set conveyors  34 , after which (as will be described) the gantry  84  travels laterally to a position over the pallet  90 . The sod carrier  94  then deposits its layer of sod on the pallet  90 . 
   The sod carrier  94  includes side and end frame members  96 ,  98  defining a frame for the sod carrier, and also includes upper frame members  100  spanning the side frame members  96  and connected thereto. A cross frame member  102  extends between the upper frame members  100  and supports half  104 - 1  of a ball joint  104 . The other half  104 - 2  of ball joint  104  is connected to a cross member  106  in the gantry  84 , so that the sod carrier  94  is suspended from the gantry  84  and is able to rock and tilt to a limited extent relative to the gantry  84 , and is also able to rotate with respect to the gantry  84 . 
   A rotate piston and cylinder  110  ( FIG. 7 ) is connected between a frame member of the gantry  84  and the sod carrier  94 , the attachment point on the sod carrier being spaced from ball joint  104 . The piston and cylinder  110  is connected so that it can rotate the sod carrier  94  on the gantry  84  by 90° when commanded to do so. (Alternatively, a conventional rotary actuator can be used to rotate the sod carrier on the gantry.) 
   The gantry  84  is moved on guide frame  82  between a first position over the third set conveyors  34  (shown in  FIG. 8A ) and a second position over the pallet  90  (shown in  FIG. 9B ) by an elongated double-acting (two-ended) cylinder  112  which is mounted at  114  on upper frame member  106  of the gantry  84 . An elongated piston rod  118  extends through the cylinder  112  and is mounted at both ends, at  120 ,  122 , to the guide frame  82 . A piston (not shown) is located in the cylinder  112 , so that as hydraulic fluid is injected into the cylinder  112  at either end (by hoses not shown), the cylinder  112  will travel back and forth in the direction of arrow  124 , carrying the gantry  84  with it, to move the gantry between the two positions described (one over the third set conveyors  34  and the other over the pallet  90 ). 
   The sod carrier  94  suspended from the gantry  84  is essentially the same as that shown in U.S. patent application Ser. No. 10/780,616, filed Feb. 19, 2004 entitled “Method and Apparatus for Picking Up Sod from the Top”, published Jan. 6, 2005, the description and drawings of which are incorporated by reference herein. Since the sod pick-up features of the sod carrier  94  are fully described and illustrated in such published patent application, those features will be described only briefly here. Specifically, the sod carrier  94  includes (see  FIGS. 7 ,  8 A) a number of pairs of clamps  130  which extend parallel to each other at the bottom of the sod carrier  94 . The clamps  130  are strongly biased to a closed position by springs  132  but can be opened by a linkage  134  (not shown in detail in this application) which is operated by a piston and cylinder  136 . 
   In operation, as described, three sod strips travel up the first and second conveyor sets  30 ,  32  and onto the third conveyor set  34 . Since the three sod strips are not usually perfectly aligned (as mentioned, the middle sod strip is ahead of the two side sod strips, and the two side sod strips may slip unequally on the conveyors), each conveyor of the third conveyor set is separately driven and controlled (as described) to shut off individually when its sod strip is properly positioned on the third conveyor in question. This ensures that all three sod strips on the third conveyor set are aligned evenly with each other and ready to be picked up. If the sod is defective, the operator can manually override (using a manual control, not shown) the sensors which normally stop the third conveyor set  34  and can cause the third conveyor set  34  to continue operating, thus ejecting the defective sod pieces onto the ground. 
   As shown in  FIG. 1 , the third conveyor set  34  is mounted in a bed frame  140  which can be raised and lowered using piston and cylinder sets  142  at each side of the bed frame (and with additional conventional guides, not shown). When the three sod strips are aligned on the third conveyor set  34 , thus shutting off all of the third conveyors  34 - 1 ,  34 - 2 ,  34 - 3  as previously described, a computer  144  (described below in connection with  FIG. 10 ) sends a signal to operate the pistons and cylinders  142  (part of hydraulic circuit  145 ,  FIG. 10 ), raising the conveyor bed frame  140  and pressing the sod strips on the third conveyor set  34  against the clamps  130  on the underside of the sod carrier  94 . At this time, the sod carrier  94  is pushed against the gantry  84 , and the pressure is transmitted to the gantry by rubber pads  95  atop the sod carrier and which press against the underside of the gantry. Besides absorbing pressure when the sod carrier  94  is pushed against the gantry  84 , the rubber pads  95  serve an additional purpose. If the sod strips on the third conveyor set  34  happen to be of uneven thickness, e.g. thicker at one side of the third conveyor set than the other, then the rubber pads  95 , together with the limited rocking and tilting permitted by ball joint  104 , permit the sod carrier  94  to tilt to compensate at least to some extent for the uneven thickness, allowing the clamps  130  to clamp all of the sod strips on the third conveyor set  34 , rather than failing to clamp some of the sod strips. 
   If it is desired to cut the sod strips  14 - 1  to  14 - 3  each into two shorter pieces, a knife  146  ( FIG. 4D ) can be fixed in the underside of sod carrier  94  as described in the above-mentioned published pending application, thus dividing each sod strip  14 - 1  to  14 - 3  into two parts. The computer  144  typically operates control solenoids valves  147  in the hydraulic circuit  145  to operate the pistons and cylinders described. The pressure with which the conveyor bed frame  140  presses the sod strips on the third conveyor set  34  against the clamps  130  is preferably made adjustable, to allow better gripping of the sod by the clamps when the sod is of different soil types. (For example, for tough soil, a higher pressure is needed.) 
   The pressure with which the bed frame  140 , and hence the sod strips  14 - 1  to  14 - 3  are pressed against the underside of the sod carrier  94  is sensed by a pressure sensor  148  ( FIG. 10 ) connected to one of the piston and cylinders  142  which raise the bed  140 . When the pressure is sufficiently high, this is detected by the computer  144  which then sends a signal to a solenoid valve controlling the clamp piston and cylinder  136 , depressurizing this piston and cylinder and allowing the springs  132  to snap the clamps  130  closed. The clamps  130  then grip the sod by its blades, as described in the above published co-pending application. In some cases, if the equipment is likely to operate over muddy ground and if the mud may clog the clamps  130  and prevent them from gripping the sod strips properly, a series of hooks  150  (FIG.  11 ) may be added to the clamps, to provide improved grip by the sod carrier  94  on the sod strips. The hooks  150  are relatively short and will not support the sod strips by themselves, so that when the clamps  130  are opened, the sod strips  14 - 1  to  14 - 3  (which are heavy) will quickly drop away from the sod carrier  94 . (If a sufficient number of closely spaced hooks  150  are used, then these hooks are capable of supporting the sod strips by themselves and can in effect constitute a clamp. When the hooks are separated by the clamp opening action, then the heavy sod strips will drop away from the hooks  150 .) Alternatively, the clamps can be formed as a series of straight or curved fingers. 
   After sufficient time has been provided for the clamps  130  to close and to grip the sod strips (typically only a very short time will be required for this), the computer  144  sends a signal to a solenoid valve in the hydraulic circuit  145  controlling pistons and cylinders  142  to lower the conveyor bed frame  140  so that the third conveyors will be in position to receive the next set of sod strips when they arrive from the second conveyor set  32 . The computer  144  then also sends a signal to activate the gantry travel cylinder  112 . The gantry  84  then moves to the right as shown in  FIG. 9A  until the gantry  84  with the sod carrier  94  and the sod strips  14 - 1  to  14 - 3  suspended therefrom is over the pallet  90 . At this point, a proximity sensor  152  ( FIG. 9A ) on the guide frame  82  operates, sending a signal to the computer  144  which then stops the operation of cylinder  112 , ending further lateral travel of the gantry  84 . At the same time (or a few milliseconds later) the computer  144  sends a signal to the hydraulic circuit  145  to operate the clamp piston and cylinder  136  to open the clamps  130 , thus allowing the sod strips  14 - 1  to  14 - 3  which were suspended from the sod carrier  94  to drop onto the pallet  90 . After this operation has occurred, the computer  144  signals the hydraulic circuit  145  to operate gantry cylinder  112  in the opposite direction, to return the gantry and the sod carrier to the position shown in  FIGS. 8A and 9A , over the third conveyor set  34  and ready to pick-up another set of sod strips. A proximity sensor  153  at the other (home) end of guide frame  82  signals the computer  144  to stop this return gantry movement when the gantry  84  has returned to its starting (home) position. It will be realized that instead of, or in addition to, raising the conveyor bed frame  140 , the sod carrier  94  can be lowered so that the sod strips are contacted by the clamps  130  which press against the sod strips on the third conveyor set  34 , to then lift the sod strips. 
   When a pallet  90  is being loaded with sod strips or slabs, then after a number of layers have been deposited with the sod strips oriented in one direction, additional layers can be deposited with the sod strips oriented at 90° to the first direction, to tie together the load of sod strips on the pallet and to render it more stable. A typical loaded pallet  90  is shown in  FIG. 12 , with four layers of sod strips  160  running in one direction (perpendicular to the page) and the next four layers  162  running at 90° to the first direction. To accomplish this, the sod carrier  94  is, as previously described, mounted on the gantry  84  so that the sod carrier  94  can rotate through  900 , powered by piston and cylinder  110 . For this purpose, the gantry  84  contains ( FIGS. 7 ,  8 A) a home sensor  166  and a home stop  170 , while the sod carrier  94  includes a home stop  174  and an away stop  176  and an away sensor  168 . When the sod carrier is in the non-rotated position shown in  FIGS. 7 ,  8 A, home stop  174  on the sod carrier  94  presses against home stop  170  and home sensor  166  on the gantry. In this condition, the computer  144  is signalled to maintain low pressure in rotate cylinder  110  to hold the sod carrier  94  in the home position shown in  FIG. 8A , and not to rotate the sod carrier  94  to a different position. 
   After a desired number of layers of sod have been deposited on the pallet  90 , then the computer will be signalled (by means to be described), after the sod carrier has picked up a load of sod strips to operate the rotate cylinder  110  to rotate the sod carrier  94  by 90° with respect to gantry  84 . When the sod carrier  94  has rotated 90°, away sensor  168  on the sod carrier  94  will press against away stop  176  on the gantry  84 . The away sensor  168  sends a signal to the computer  144  to terminate the rotation but to maintain low pressure in the rotate cylinder  110  to hold the sod carrier  94  in the 90° rotated position, so that sod strips can be deposited on the pallet  90  at 90° to the first set of sod strips. The computer  144  can be programmed to set as desired the number of layers of sod strips to be deposited on the pallet in one orientation before the next set of layers is deposited at 90° to the first set, and can also be programmed to adjust the number of sod layers deposited in one orientation before a 90° rotation occurs. After the clamps  130  are activated to release the sod, the computer reverses the operation of the rotate cylinder  110  to return the sod carrier  94  to its non-rotated condition (as it returns to its home position). 
   The pallet  90  is supported on the forks  180  of a conventional forklift  182  (best shown in  FIGS. 13 ,  14 ). The forklift  182  is located in a space beside the third conveyor set  34 , which space is of sufficient size to accommodate the pallet  90 . At the beginning of a sod harvesting operation, the forks  180  are raised upwardly so that the pallet  90  is positioned only a short distance below the sod carrier  94 , so that the sod strips when released from the sod carrier will fall only a short distance and will be properly aligned on the pallet  90 . 
   As layers of sod strips are deposited on the pallet  90 , the pallet  90  will have to be lowered to make room for the increasing height of the layers stacked on the pallet. The lowering operation is controlled by an “electric eye”, consisting of a light beam projector  184  ( FIG. 15 ) mounted at one side of the pallet  90  and projecting its light beam  186  over the upper surface of the pallet to a photocell  188  on the opposite side of the pallet. Signals from the photocell are directed to the computer  144 . A brief interruption of the light beam  186  (caused by sod dropping from the sod carrier through the light beam onto the pallet) will not trigger any lowering of the pallet, but a longer duration interruption of the light beam  186  (e.g. one second or more) will cause the photocell  188  to send a signal to the computer  144 . The computer  144  then signals the hydraulic circuit  145  to cause the forklift left cylinder  180  to lower the forks  180 . The lowering can be by a fixed amount which is approximately equal to the thickness of a sod strip, or it can be until the photocell  188  receives the light beam again from the projector  184 , at which time the lowering operation is stopped by the computer  144 . The number of lowering steps which occur after the pallet  90  is loaded onto the forks  80  is counted by the computer  144 , and when the desired number of lowering steps has occurred, then the computer sends a rotate signal so that the next predetermined number of sod layers will be loaded onto the pallet  90  with the sod strips oriented at 90° to the previous set of layers. 
   It will be appreciated that for the 90° rotation feature to be effective, the sod carrier must pick-up the sod strips while in one orientation and must then rotate 90° in order to deposit the sod strips (on the pallet) at 90° to the first orientation. Therefore, the sequencing by the computer  144  is such that when the sod carrier  94  is positioned over the third conveyor set  34 , the sod carrier  94  is always in the “home” position indicated in  FIGS. 7 and 8A . The gantry  84  with the sod carrier  94  suspended therefrom can then travel to the “away” position shown in  FIG. 9B , with the sod carrier  94  either in the  FIG. 8A  position, or rotated through 90° therefrom. The two alternative “away” positions of the sod carrier  94  can be referred to as the “unrotated away position” and the “rotated away position”. The sod carrier  94  must be fully in one of these two positions before the computer  144  will signal the hydraulic circuit  145  to open the clamps  130  and drop the sod strips onto the pallet  90 . Therefore, the signals from the proximity sensor  152  indicating that the gantry  84  has fully reached the “away” position, and from the sensors  166 ,  168  indicating that the sod carrier is fully either in the unrotated away position or in the rotated away position, are required before the clamps  130  are opened to release the sod strips. 
   It will be appreciated that the gantry  84  must travel back and forth rapidly, and that the sod carrier must rotate rapidly, to complete their required movements in the relatively short time period available between the arrivals of successive sets of sod strips. The resultant rapid accelerations and decelerations can heavily shake the sod harvester  10 . To reduce this tendency, the sod harvester  10  is supported at its rear end, beneath the third set of conveyors  34 , by a heavy roller  192  ( FIG. 15 ). The roller  192  serves to dampen and reduce the amplitude of vibrations occurring when the gantry and sod carrier are accelerating and decelerating. The roller  192  also helps to support the load of the harvester, particularly when it is carrying a pallet loaded with sod and a stack of empty pallets, and also serves better to balance the machine. A piston and cylinder  194  can be provided to adjust the weight division between the roller  192  and the rear wheels  196  of the harvester, and also to raise the roller  192  off the ground when the cutting knives are raised from the ground, so that the harvester  10  can travel. 
   In place of roller  192 , a set of wheels of a suitable hardness may be used. 
   When the pallet  90  is full of sod and is ready to be discharged, it is preferred that it be placed on the ground in a position in which it will be out of the path of the return movement of the sod harvester during a harvesting operation. Therefore, the forklift mast  200  is preferably mounted on a rod  202  ( FIGS. 13 ,  14 ) and can be side shifted using a side shift piston and cylinder  204 , as is well-known in the industry, so that before the pallet  90  is lowered onto the ground, it is side shifted as far as possible to one side of the harvester. 
   The foregoing description has discussed harvesting three side-by-side strips so that a complete layer for the pallet can be picked up and deposited on the pallet, thus eliminating the need for separate movements to build up a layer on the pallet from separate pieces. Transferring an entire layer onto the pallet is more efficient than transferring only part of a layer, although if desired, the features of the invention can be used to transfer part of a layer in one operation and then to transfer further parts of the layer in additional operations. 
   If the harvester  10  is used to harvest only a single wide slab or strip of sod and then send that strip up conveyors to be picked up and placed on a pallet, then variations can be made in the apparatus described. For example, while three sequential sets of conveyors are still desirable, with each travelling faster than the preceding set to produce a gap or time interval between the times when successive pieces of sod arrive at the buffer conveyor (i.e. at the third conveyor), it may be less necessary to have the third conveyor travelling faster than the second conveyor, since the gap produced by the differences in speed between the first and second conveyors may be sufficient for sod pick-up and deposit operations. In any event, while a one/two/three speed ratio is preferred for the three conveyor sets (i.e. ground speed for the first set, double ground speed for the second set, and three times ground speed for the third set), these speeds can be varied depending on the need, so long as a sufficient time interval is produced between the arrivals of successive sets of sod pieces to allow the set on the buffer conveyor or conveyors to be picked up. Also, additional conveyor sets can be included in the sequence, either for further movement of the sod, or to increase the size and duration of the gap between sod strips arriving at the buffer conveyor, or both. 
   Reference is next made to  FIGS. 17 and 18 , which show diagrammatic views of a sod harvester according to the invention mounted on the side of a tractor, rather than being pulled by a tractor. Prime reference numerals are used to indicate parts corresponding to those of  FIGS. 1 to 16 . 
   The sod harvester  10 ′ shown in  FIGS. 17 ,  18  is essentially the same as that shown in the preceding FIGS., with respect to the components used to harvest sod, move it upwardly and rearwardly along three sets of conveyors  30 ′,  32 ′,  34 ′, and then pick up the sod slabs using the sod pick-up and transfer mechanism  80 ′. However, the harvester  10 ′ is now mounted on the side of a tractor  210 , employing a conventional mounting mechanism (not shown). 
   The feature of particular interest in the harvester  10 ′ is the use of “bogie” wheels  214  which help to support the harvester. If the harvester is designed to cut a wide set of sod slabs, then the harvester will be heavy and needs the bogie wheels for support. As shown in  FIGS. 17 ,  18 , the bogie wheels  214  are mounted on an axle  216  which has its axis aligned (in a front to rear direction) with the axis of axle  218  of the tractor rear wheels  220 . (As shown in  FIG. 18 , since bogie wheels  214  are of smaller diameter than the tractor rear wheels  220 , the bogie axle  216  is not aligned in a vertical direction with axis  218  of the tractor rear wheels, i.e. axle  216  is below axle  218 .) 
   The bogie wheels  214  are not fixed immovably to the harvester  10 ′, but rather are mounted on a suspension comprising a beam  222  extending in a front to rear direction and supporting the axle  216 . The front end of beam  222  is mounted at pivot  224  on a cross beam  226  of the harvester  10 ′, so that the harvester bogie wheels  214  can move upwardly and downwardly in the direction of arrow  228 . 
   The rear end of beam  222  is pivotably connected at  230  to a piston and cylinder  232 , the upper end of which is connected at pivot  234  to another cross beam  236  of the harvester  10 ′. 
   With the arrangement shown, a desired amount of pressure can be applied to the bogie wheels  214 , using piston and cylinder  232 , to support a portion of the weight of the harvester. Appropriate damping means (similar to a shock absorber) can if desired be incorporated into piston and cylinder  222 , to absorb shocks and provide some resiliency as the harvester  10 ′ travels over undulating ground. In fact, piston and cylinder  222  can be a shock absorber, pressurized with air. In addition, other suspension arrangements can be used, e.g. a piston and spring combination. 
   Similar to the previous embodiment, the axle of the rear roller  192 ′ is supported by a beam  240  pivotably mounted at  242  to a fixed member  244  of the harvester. A piston and cylinder  246  pivotably connected between an extension  248  of the beam  240  and a fixed member  250  of the harvester allows a desired amount of pressure to be transferred to the rear roller  192 ′. In addition, as before, when the cutting knives of the harvester  10 ′ are raised out of the ground, the rear roller  192 ′ will normally also be automatically raised above the ground by piston and cylinder  246 , to allow for travel of the harvester  10 ′. During such travel, the weight of the harvester  10 ′ will be supported by the tractor  210  and by the bogie wheels  214 . 
   While the cutting knives  12 - 1 ′,  12 - 2 ′,  12 - 3 ′ have been shown in fixed relation, they can if desired be made adjustable. For example, as shown in  FIG. 17 , the right hand cutting knife  12 - 3 ′ can be fixed to the harvester, but the two left hand cutting knives  12 - 1 ′ can be made adjustable in a side-to-side direction, e.g. by mounting them on a beam  252  with a number of sets of mounting holes, so that the knives  12 - 1 ′,  12 - 2 ′ can be bolted to beam  252  using one of several available sets of mounting holes for each knife. In this way, the size of the narrow sod strip to be left in the field for regrowth after sod slabs have been cut and removed, can be varied depending on the sod grower&#39;s preference. In  FIG. 17 , the sod cutting knives  12 - 1 ′ to  12 - 3 ′ have been shown as aligned in a front to rear direction, which assumes a moderate spacing between the sides of the sod slabs being cut. If a zero spacing is desired (as previously described), then the center knife  12 - 2 ′ can be offset forwardly or rearwardly, as previously discussed. 
   Reference is next made to  FIGS. 19 to 21 , which show a different way of stacking sod on a pallet from that shown in  FIG. 12 , but which also serves to tie the stacked sod on the pallet together. As shown in  FIGS. 19 to 21 , a first layer  300  consisting of three sod strips is deposited on the pallet  90 . A second layer  302  also consisting of three sod strips is then deposited on top of the first layer  300 , but layer  302  is offset sideways by a small amount (e.g. one inch to two and a half inches, or more if desired) with respect to layer  300 . Then the next layer  304  is deposited on top of layer  302 , but with the side edges  304   a  of layer  304  aligned with the side edges  300   a  of the first layer  300  and therefore overlapping the side edges  302   a  of layer  302 . The overlap is indicated at  305  in  FIG. 19 . As successive layers are stacked, each layer overlaps the side edges of the sod strips on the layer beneath it. The weight of the sod pressing on the overlapped portions ties the slabs of sod together when stacked on a pallet and makes unnecessary the need for rotating sets of layers through 90°, as described in connection with  FIG. 12 . This eliminates the need for the rotating mechanism of the sod carrier  94 , thus substantially simplifying the apparatus. 
   To practice the method described in connection with  FIGS. 19 to 21 , the proximity switch  152  ( FIG. 9A ) which controls the position at which the sod carrier  94  ends its sideways travel and drops a layer of sod onto the pallet  90 , can be modified to sense the two overlapped positions required, or alternatively (and preferably) the computer  144  may be programmed simply to allow (for example) one inch or more of additional movement of the sod carrier  94  on each alternating trip of the sod carrier  94  over the pallet  90 . 
   Another way to practice the method described in connection with  FIGS. 19 to 21  is to use the feature that the forklift  182  has a side shift piston and cylinder  204  ( FIG. 13 ). The side shift piston and cylinder  204  may be controlled by the computer  144  to shift the pallet  90  sideways by the required distance (e.g. one to two and a half inches, or more) just before the sod carrier  94  drops a layer of sod on the pallet  90 , so that alternating layers are overlapped as described. 
   In addition, instead of offsetting alternating layers (in which case each layer is offset with respect to the layer beneath it), such offsetting can be done every third layer, or every fourth layer, or as desired, so long as the stack of layers are adequately tied together on the pallet  90 . 
   Reference is next made to  FIGS. 22 to 24 , which show the situation when each sod strip  14 - 1  to  14 - 3  is cut into two pieces by a cross cut knife such as knife  146  of  FIG. 4D . In the example illustrated, this results in six sod pieces  14 - 10  to  14 - 15  inclusive. Each piece has a pair of longitudinal edges, indicated at  350 , and a pair of lateral or widthwise edges, indicated at  352 . When these layers are stacked on a pallet, overlap can be provided both widthwise (as also shown in  FIGS. 19 to 21 ) and lengthwise (in which case at least some of the widthwise edges  352  are overlaid by the sod above them). 
   The overlapping of the longitudinal edges  350  can be accomplished, as described for  FIGS. 19 to 21 , by programming the computer  144  to cause the sod carrier  94  to travel to different positions over the pallet  90  as alternate layers of sod are deposited. Thus, using the signal from proximity switch  152 , and under control of computer  144 , the sod carrier  94  alternatingly deposits the sod on the pallet  90  in two positions, one overlapping the other by between one and two and a half inches (all dimensions are exemplary) to provide the widthwise overlap indicated at  354  ( FIG. 22 ). 
   The lengthwise overlap of the widthwise edges  352 , such overlap being indicated at  356  in  FIG. 22 , may be provided in various ways. One method, as shown in  FIGS. 25 to 29 , is to mount the forks  180  on the forklift mast  360  by a scissors mechanism diagrammatically indicated at  362 . The scissors mechanism  362  may be operated in conventional manner by a piston and cylinder (not shown) to move the forks  180  in a lengthwise direction, towards and away from the mast  360  as shown in  FIGS. 25 to 28 . This movement will shift the sod pieces in a lengthwise direction, producing the lengthwise offset or overlap indicated at  356  in  FIG. 22 . Again, operation of the scissors mechanism  362  is controlled by computer  144 , so that the correct movement occurs at the correct time. The amount by which the scissors are extended can be controlled by a microswitch or a proximity sensor, not shown. 
   As described in connection with  FIGS. 19 to 21 , the lengthwise overlap  356 , as well as the widthwise overlap, can be of every alternate layer, or every second, third or fourth layer, or as desired so long as the stacks of sod pieces are tied together sufficiently to result in a stable pile of sod on the pallet  90 . 
     FIGS. 25 and 26  show the scissors  362  retracted and the forks side shifted right, while  FIGS. 27 and 28  show the scissors  362  extended and the forks side shifted left. 
   In some cases, the harvester may cut a single wide sod strip  14 , as shown in  FIG. 29 , and such wide sod strip may then be cut into desired pieces  400 - 14  by knives  146 A (similar to knife  146 ) located in the bottom of the sod carrier  94 . As before, the cutting occurs when the conveyor bed frame  140  carrying the sod strip  14  is pressed against the bottom of the sod carrier  94  (or when the sod carrier  94  is pressed against the third set conveyors  34  on the bed frame  140 ). The sod piece  14  can in this manner be cut into any desired number of pieces, e.g. two pieces, three pieces, four or six pieces. Stacking of these pieces may be performed as described for  FIGS. 19 to 24 , with each layer offset in a widthwise (lateral direction) as described for  FIGS. 19 to 21 , and if the sod slab is cut crosswise into several pieces in a lengthwise direction, then the overlap will also be as described for  FIGS. 22 to 24 , i.e. in a front to rear (lengthwise) direction. 
   Reference is next made to  FIGS. 31 to 37A , B, C which show diagrammatically an automatic pallet injector  400  according to the invention, to enable the harvester to cut sod continuously without having to stop to eject a completed sod stack and load a new pallet. It will be appreciated that if the harvester has to stop each time a loaded pallet is to be discharged, then use of the harvester will be much less efficient than if continuous operation were possible. 
   As shown in  FIGS. 31A , B, C, the pallet injector  400  includes a pallet support structure  402  comprising a set of support rails  404 . The rails  404  are spaced laterally apart to carry a stack  406  of pallets. The stack  406  of pallets is normally confined in a hopper shown in dotted lines at  408 . The rails  404  and the bottom pallet  410  in the stack are located beneath and clear of the bottom of the hopper  408 . 
   The rails  404  support an injector sheet  412  which in turn supports the bottom pallet of the stack  406  and is movable on wheels  414  rolling on rails  404  between an extended position shown in  FIGS. 31A , B, C and a retracted position shown for example in  FIGS. 32A , B, C. In the retracted position, the injector sheet  412  is located over the rails  404  and does not protrude beyond the front edge  413  of the hopper  408 . Any desired mechanism, e.g. pistons and cylinders (not shown) can be used to move the injector sheet  412  between its extended and retracted positions. Injector sheet  412  can also move on slides or in any other known way. Proximity sensors or microswitches (not shown) control the extent of the extension and retraction of the injector sheet  412 , by sending position signals in conventional manner to computer  144 . 
   In  FIGS. 31 to 34A , B, C, the forks  180  are in a lowered position (it is assumed that they have just discharged a pallet loaded with sod). In  FIGS. 32A , B, C, the injector sheet  412  is in its retracted position, and in  FIGS. 33A , B, C, the injector sheet  412  is shown in its extended position, supporting a pallet  410  over the forks  180 . The injector sheet  412  may typically include small barbs or the like, e.g. crosswise bars or tubes (not shown) to grip the bottom of the bottom pallet  410  and move it forwardly, out from under the remaining pallets in the stack  406 . Movement of the remaining pallets in stack  406  is prevented by the walls of the hopper  408  in which they are located. 
   After the bottom pallet  410  has been dispensed from the stack  406  of pallets and is located over the forks  180 , the pallet  410  is temporarily supported by the injector sheet  412  while stacking of sod pieces on pallet  410  begins. It is necessary for injector sheet  412  to temporarily support the pallet  410  at this time, since the forks  180  will have just finished supporting a previously fully loaded pallet of sod and are not yet available to hold a new pallet. Since the harvester is continuing to harvest sod and needs to stack the newly harvested sod without interruption, therefore the required temporary support of pallet  410  is provided by the injector sheet  412 . 
     FIGS. 34A , B, C show the pallet  410  supported temporarily by the injector sheet  412  and with the first two, three or four (or more) layers of sod  420  stacked on the pallet  410 . The forks  180  are still shown in their lowered position. 
     FIGS. 35A , B, C show the forks  180  in raised position in which they have now taken over the job of supporting the pallet  410 , with several layers of sod  420  thereon. As will be evident from  FIGS. 31 to 33A , the injector sheet  412  contains laterally spaced apart slots  421  through which the forks  180  can pass, so the forks can take over supporting the pallet from the injector sheet  412 . Although injector  412  has been shown as a sheet, separate tubes or rods can be used if desired to form the injector and to provide sufficient temporary support for the partly loaded pallet  410 . When the forks  180  take over the job of supporting the pallet  410 , they raise the pallet above the position in which it was formally supported by the injector sheet  412 , by about two inches. The precise amount by which the forks lift the pallet above the injector sheet can be varied, but should be enough to ensure that the pallet is above the injector sheet  412  and does not obstruct withdrawal of the injector sheet  412  to its retracted position. 
   Once the. forks  180  have taken over the task of supporting the loaded pallet  410 , the injector sheet  412  may be withdrawn to its retracted position (shown for example in  FIGS. 32 ,  36 A, B, C). The harvester  10  then continues to stack sod on the pallet  410  until the pallet is fully loaded, as previously described, at which time the electric eye  184 ,  188  ( FIG. 15 ) causes the computer  144  to control the forks  180  to lower the fully loaded pallet  410  to the ground for discharge ( FIGS. 36A , B, C). When the pallet  410  is lowered to the ground, then since it is facing rearwardly, it will be discharged as the harvester moves forwardly away from it. Downward movement of the forks  180  at this time is terminated by a proximity sensor  421  at the bottom of the fork mast. Sensor  421  signals the computer  144  to end lowering of the forks at this time. After the loaded pallet has been discharged from the forks  180  (the computer provides a short time interval for this after proximity sensor  421  has been activated to stop the lowering of the forks), then the computer  144  causes the forks to be raised again, to support a new pallet which has been injected. 
   A second electric eye sensor, shown in  FIG. 35C  as having a light beam projector  422  and a photocell  424 , is located below the electric eye  184 ,  188 . Electric eye  422 ,  424  senses when the top of the finished sod stack passes photocell sensor  424  on the travel of the finished sod stack down to the ground. The signal from the second electric eye  422 ,  424  is transmitted to the computer  144  to inform the computer that the top of the loaded pallet being lowered is now below the level of the injector sheet  412 . The computer then actuates the injector sheet  412  to remove a new pallet from the bottom of the stack  406  and to move it forward into the sod stacking position shown for example in  FIGS. 34A , B, C. As described, the injector sheet  412  remains in its extended position and supports the new pallet  410  for stacking of the first two or more layers of sod, to allow time for the previous sod laden pallet to be ejected and for the forks  180  to rise back up to support the new pallet  410 . The upward travel of the forks  180  at this time may be controlled and stopped by a proximity sensor, diagrammatically indicated at  426 , on the mast  360 . As mentioned, the forks are stopped after they have raised the new pallet  410  clear of the injector sheet, to allow the injector sheet to be withdrawn. A sequence detector function in the computer  144  detects that the upward movement of the forks has terminated, and then signals the injector sheet  412  to return to its retracted position shown, for example, in  FIGS. 32A , B, C. 
   The proximity sensor or microswitch (not shown) which terminates the movement of the pallet injector sheet  412  back to its retracted position, also signals or enables the start of the first set  184 ,  186  ( FIG. 15 ) of electric eyes&#39; function to lower the forks  180  during stack building as required. (It will be understood that the forks  180 , when they are supporting a loaded pallet, should not be lowered until after the injector sheet  412  has been fully retracted, so that the pallet does not interfere with the injector sheet retraction.) 
   While the lowering of the fully loaded pallet during stack building has been described as initiated by the first electric eye set  184 ,  185 , such lowering can be accomplished in other ways. For example, the computer  144  can count the layers deposited on the pallet by the sod carrier, and after the count has reached (for example)  30  to  35  layers, then lowering of the loaded pallet can be initiated. 
   Reference is next made to  FIGS. 38 ,  39  which show an alternative and relatively low cost way of obtaining overlap between slabs of sod stacked in successive layers on a pallet. As shown in  FIGS. 38 ,  39 , each layer  500 ,  502  (only two layers are shown) may be rotated slightly, typically between 5° and 10°, with respect to the layer below it. For example, the second layer  502  may be rotated 5° to 10° counterclockwise (as shown) with respect to the first layer  500 . The third layer (not shown) may be aligned with the first layer  500 . The fourth layer (not shown) may be aligned with the second layer  502 . A 5° rotation of a sod layer that is 48″ by 48″ will produce approximately a two inch overlap, or overhang, as indicated at  504  in  FIG. 38 . 
   With the method of stacking shown, sufficient overlap is achieved to tie the stack together so that it is more resistant to damage when travelling. Since the amount of rotation used is small, the limited rotation needed can be achieved quickly (in much less time than that needed for a 90° rotation). In addition, since only limited rotation is used, the loaded pallet is not appreciably larger in plan view from a pallet where no overlap between successive sod layers is provided. 
   The rotation needed for the overlap in  FIGS. 38 ,  39  can be achieved by any appropriate mechanism. For example, the rotate cylinder mechanism  110  of  FIG. 7  can be used. 
   Reference is next made to  FIGS. 40 ,  41 , which show another way of achieving overlap between successive layers of sod slabs. As shown in  FIG. 40 , a pair of vertical piling walls  510 ,  512  are provided. The walls  510 ,  512  define a piling cavity  514  which accommodates a pallet  520  with very close tolerances, thus forming a “tight” piling cavity. The pallet  520  is located in cavity  514  and is initially above the bottom edges  516  of the piling walls  510 ,  512 . 
   In operation, a first layer  520  (formed by three sod slabs) is deposited into the cavity  514  in a position displaced toward one of the piling walls  510 , so that one edge  522  of the first sod layer is curled upwardly. 
   A second sod layer  524  is then deposited into the piling cavity  514  in a position such that the edge  526  of the second sod layer opposite to the edge  522  of the first sod layer is displaced toward the piling wall  512 , causing the edge  526  of the second sod layer to curl upwardly. This process is continued with alternate sod layers, resulting in the stack shown in  FIGS. 40 ,  41 , in which sod layers slightly overlap the sod layers beneath them. To achieve this result, each sod layer must be moved to a sideways offset position with respect to the sod layer below it. This can be accomplished, for example, by any of the mechanisms previously described. Since the sod is not resilient, but rather is somewhat moldable, it is found, as shown in  FIG. 41 , that the upturned edges of the sod layers remain upturned when the pallet is removed from the cavity  514 , thus helping to tie the sod stack together. An advantage of this system is, for example, that 54 inch side sod slabs can be cut (instead of the usual  48  inch slab), and yet because of these upturned edges on the pallet, they will only occupy a width of (for example) 50 inches, thus enabling storage of more sod on a pallet of given width. 
   Reference is next made to  FIGS. 42A ,  42 B to  FIGS. 47A ,  47 B, all of which show various forms of pallet which cause a concave (as viewed from above) stack of sod slabs to be formed. In  FIGS. 42A ,  42 B, a pallet  540  is shown having a shallow V-shaped upper surface  542  (as viewed from one end of the pallet). The V-shaped upper surface  542  results from forming the pallet to be thicker at its side edges  544  than at its center  546 . 
   When sod is stacked on the pallet  540 , as shown in  FIG. 48 , the stack  550  of sod layers will have a concave upper surface  552 , i.e. its outer edge portions will extend upwardly as well as outwardly. This acts in a manner similar to overlapping the sod slabs and thus strengthens the sod stack against falling apart during travel. Since this method does not require any side shifting or rotation of the sod slabs, the machine for stacking the sod can be simplified, although there is a cost for the special pallets. 
   The pallet  540 - 2  shown in  FIGS. 43A ,  43 B is similar to pallet  540  shown in  FIGS. 42A ,  42 B except that the upper surface  542 - 2  of the pallet  540 - 2  is concavely curved, rather than being V-shaped. 
   The pallet  540 - 3  shown in  FIGS. 44A ,  44 B is simplified in that it has a flat upper surface with upwardly protruding edges  552  (which if the pallet is made of wood can be formed simply by adding an extra piece of wood or rail  554  to each side of the pallet). Provided that the pallet is no wider than the layer of sod to be deposited on it, the upwardly protruding edges  552  will cause a sod stack deposited on the pallet to have a concave upper surface, with upwardly and outwardly protruding edges, as described in connection with  FIG. 48 . 
   If desired, and as shown in  FIGS. 45A ,  45 B, the upwardly protruding rails  554  which have been added to the side edges of the pallet can be located on all four sides of the pallet  540 - 4 , thus making the sod stack piled on this pallet even more resistant to vibration. 
     FIGS. 46A ,  46 B show a pallet  540 - 5  having a concave upper surface formed from three flat sections  560 ,  562 ,  564 . The outer sections  560 ,  564  provide openings  566  at each lower side of the pallet for a forklift. 
   Alternatively, the pallet  540 - 6  can as shown in  FIGS. 47A ,  47 B have a V-shaped upper surface with side edges dimensioned such that the bottom center of the “V”  570  as well as the bottoms of the side edges  544 - 6  all rest on the ground, providing three lines of support for the pallet  540 - 6 . 
   In some cases, it may be desirable to cut an elongated slab of sod, as shown at  580  in  FIG. 49 , and then to cut slab  580  partially into two sections  580 - 1 ,  580 - 2  which are connected by small pieces of earth and root  582 . The two pieces or sections  580 - 1 ,  580 - 2  can readily be pulled apart when the sod is to be laid, but prior to being pulled apart, the connecting portions  582  perform a function similar to overlapping, in that they tie the two pieces  580 - 1 ,  580 - 2  together and thus help stabilize the sod stack against falling apart during activities such as transporting the sod stack. 
   To perform its function of leaving the two parts of the sod slab  580  connected, the cross-cut knife  584  (which normally cross-cuts the sod while the sod is still in the ground) is provided with two notches  586 , each extending from the lower edge  588  of the cutting knife  584  upwardly and having a height approximately equal to the thickness of the sod slab. The height can be slightly less than the thickness of the sod slab (which would weaken the connection) or it can be equal to or greater than the height of the sod slab, which would leave a connection of thickness equal to the full thickness of the sod slab  580 . 
   Reference is next made to  FIGS. 50A ,  50 B,  50 C, which show variations of the notches in the cross-cut knife  584 . In  FIG. 50A , a single V-shaped central notch  590  is provided in the bottom of the cross-cut knife  584 , so that the two sections of the sod slab  580  will be connected by a single connecting portion, which can be of desired width to achieve a suitable compromise between having the two sod sections  580 - 1 ,  580 - 2  connected together strongly enough to resist falling apart of the sod stack, and being able to pull the two sections  580 - 1 ,  580 - 2  of the sod slab apart for sod laying purposes. 
   In  FIG. 50B , a single rectangular notch  592  is provided at the center of the lower edge of the cross-cut knife  584 . 
   In  FIG. 50C , the two bottom outer corners of the cross-cut knife  584  are each bevelled or sloped, as indicated at  594 , so that a connecting portion of sod slab will occur at each side of the sod slab  580 . (It is assumed that the width of the sod slab, which is set by the standard side cutting knives used in sod harvesters, is equal to the width of the cut-off knife  584 .) 
     FIG. 50D  shows a cut-off knife  584  similar to that shown in  FIG. 50C , but with a rectangular notch  596  at each bottom corner of the knife  584 , thus also leaving a connecting portion at each side of the sod slab  580 , connecting the two sections of the sod slab. 
     FIG. 50E  shows a combination of a cross-cut knife  584 , and two conventional side cutting knives  600 , with the side cutting knives  600  spaced slightly outwardly laterally of the side edges of the cross-cut knife  584 . In other words, the cross-cut knife  584  does not span the full width of the sod slab being cut, and thus also leaves small connecting portions  582  between adjacent sections. 
   It may be desired to leave the small connecting portion or portions  582  between some sod slab sections, but not others. For example, sod slab  580  may be cut into two connected portions  580 - 1 ,  580 - 2  as described, but it may be desired to cut the next slab (not shown) completely free of slab  580 . This can be accomplished by providing additional cut-off knife sections shown in dotted lines at  602  in  FIG. 50E . Knife sections  602  are normally positioned out of the gaps  582  but can be moved into gaps  582  by any desired means, to produce a full cut completely across the width of the sod slab  580 . 
   It will be realized that sod harvesting and stacking machines of the kind described may be used to harvest sod from many different fields of sod. In some cases, it may be important not to contaminate a field containing one variety of sod with seeds and roots from a different variety of sod which was growing in a field on which the harvester was previously working. The danger of such cross-contamination between two fields of sod can be reduced by providing the harvester with an air compressor, shown for example in dotted lines at  610  in  FIG. 2 . The air compressor  610  is connected to one or more air hoses  612  (also shown in dotted lines in  FIG. 2 ), and each equipped with a conventional trigger operated blowing nozzle  614 . The air compressor  610  can be separately powered by its own gasoline engine, or it can be operated by a hydraulic motor on the harvester  10 , or it can be operated from the powered take-off of the towing vehicle. In use, when the harvester is moving to a new field containing a different variety of sod than was previously harvested, the air compressor  610  is started and the nozzles  614  are used to clean with compressed air the parts of the harvester  10  which are most likely to carry seeds or root portions, e.g. the undercutting, side cutting and cross-cutting knives, the roller, and the sod conveyors and sod transport mechanisms. 
   As previously discussed in connection with  FIGS. 17 ,  18 , the harvester may have a plurality of sod cutting heads, e.g. three such heads to cut three side-by-side strips of sod. Depending on the nature of the sod, it may be desirable to leave uncut strips of sod in the field between the cut strips which have been removed. The uncut strips may need to be of various widths, depending on the nature of the sod, the soil and the growing conditions. In some cases, it may be desired not to leave any uncut strip between the cut strips, but rather to clear cut the field and then to regrow a new crop of sod by reseeding the field. To facilitate adjustment of the sod cutting heads for this purpose, for example, where three sod cutting heads  650 ,  652 ,  654  ( FIG. 51 ) are used, two of the sod cutting heads  650 ,  652 ,  654  may be mounted for transverse sliding movement on a mounting frame  656  at the front of the harvester  10 ″. Where the harvester  10 ″ is mounted on the side of a tractor  210 , the two movable heads can be the two outermost heads (away from the tractor), i.e. heads  650 ,  652 . Each head  650 ,  652 ,  654  will preferably include a complete conventional sod strip cutting mechanism, including cross-cut knife, undercutting knife with side cutting blades, a hydraulic motor and mechanism to power the knives, a depth adjustment linkage, and a sod roller (all of these parts are conventional). The heads  650 ,  652  are both mounted for lateral sliding movement on a transverse frame  660  and can be moved laterally back and forth by pistons and cylinders diagrammatically indicated at  662 ,  664 . In this manner, the lateral distance between the sod cutting heads  650 ,  652 ,  654  can be easily adjusted to set the width of the uncut strips between the cut sod strips. If desired, additional clamp locks (not shown) can be provided to clamp the cutting heads to the transverse frame  660  at their set positions, in case of hydraulic fluid leakage from the pistons and cylinders  662 ,  664 . 
   Finally, reference is made to  FIGS. 52 ,  53 , which show a modified cross-cut blade arrangement which is suitable for use when a very wide sod slab is to be cut from the ground. When a wide sod slab is to be cut, a set of several undercutting knives may be used, one positioned beside the other, and with only the outer sod undercutting knives having side cutting blades to cut the edges of the slab. With such an arrangement, if the ground being cut is uneven, the side-by-side sod undercutting knives can adjust to the unevenness (since each is supported by a roller of relatively short lateral width). However, if a single cross-cut knife is used, and if the ground is uneven (for example, if there is a shallow V-shaped gully in the ground being cut), then the cross-cut knife will not cross-cut the full width of the sod slab uniformly and may not penetrate deeply enough into the ground at certain points. If this occurs, then the sod slabs being cut may not be sufficiently separated from each other, and this can cause serious problems during rolling or stacking. 
   In the arrangement shown in  FIGS. 52 ,  53 , three cross-cut knives  700 ,  702 ,  704  are mounted side-by-side on a cross-cut frame  706 . Each knife  700 ,  702 ,  704  is pivotably mounted by a pivot  710 ,  712 ,  714  on a plate  720 ,  722 ,  724 . The plates  720 ,  722 ,  724  are supported by further pivots  730 ,  732 ,  734  on the cross-cut frame  706 . 
   The pivots  710 ,  712 ,  714  have axes which are generally horizontal and which are generally aligned with the path of travel of the harvester, so that the cross-cut knives can align themselves with the contours of the ground being cut. The pivots  730 ,  732 ,  734  have axes which are generally horizontal and generally transverse to the path of harvester travel, so that (as is conventional), after the cross-cut knives penetrated the ground, these knives can tilt rearwardly (as the harvester travels forwardly) until they are lifted out of the ground. 
   A conventional mechanism is used to operate the cross-cut knives shown. In a conventional cross-cut mechanism, the cross-cut blade is raised against the pressure of a heavy spring by a cam; then the cam suddenly removes lifting support, allowing the spring or springs to drive the cross-cut blade into the ground. A similar arrangement is used in the embodiment of  FIGS. 52 ,  53 . As shown, the cross-cut frame  706  is mounted to the main frame  750  of the harvester, with guides (not shown) constraining the cross-cut frame  706  to move vertically up and down on the harvester frame  750 . As is usual for cross-cut mechanisms, leaf springs (not shown) are provided to strongly bias the cross-cut frame  706  downwardly. The cross-cut frame  706  is, however, supported by two laterally spaced cam followers  754 ,  756  which ride on the peripheries of a pair of cams  760 ,  762  mounted on a shaft  764  which is supported at its ends on the main frame  750  of the harvester. As is usual, the cams  760 ,  762  rotate at ground speed, periodically raising the cross-cut frame  706  and then suddenly removing lifting support from it (at the rearwardly inwardly extending sections  770 ,  772  of the cam profiles), thus periodically allowing the cross-cut frame to drive the cross-cut knives  710 ,  712 ,  714  into the ground to cross-cut the sod. 
   Reference is next made to  FIGS. 54 and 55 , which show another aspect of the invention. As there shown, there are two third set conveyors  34 - 1 ,  34 - 2 . Each third set conveyor is divided into (for example) three subconveyors  34 - 1   a ,  34 - 1   b ,  34 - 1   c , and  34 - 2   a ,  34 - 2   b ,  34 - 2   c . The subconveyors of each third set conveyor  34 - 1 ,  34 - 2  are linked together by chain and sprocket mechanisms (not shown) similar to chain and sprocket mechanism  46  of  FIG. 1 , so that only one of the three subconveyors of each third set conveyor need be driven to drive all three subconveyors of a third set conveyor. 
   The division of each third set conveyor  34 - 1 ,  34 - 2  into three subconveyors provides two gaps or depressions  800 ,  802  in the top of each of these conveyors, to accommodate cross-cut knives as will be explained. 
   To bridge the gaps between the subconveyors of each third set conveyor  34 - 1 ,  34 - 2 , pairs of wedge-shaped members  804  are mounted one between each adjacent pair of third set subconveyors (and are supported on the conveyor frame by means not shown). Each wedged-shaped member  804  has a slot  806  therein to accommodate the blade of a cross-cut knife (to be described). 
   The sod carrier  808  (which may be essentially the same as sod carrier  94  of  FIGS. 1  and following) supports two cross-cut knives  810 ,  812 , which are suspended over the slots  806  in the third set conveyors  34 - 1 ,  34 - 2 . Thus, when the sod carrier  808  is lowered onto sod (not shown) on the third set conveyors  34 - 1 ,  34 - 2 , the cross-cut knives  810 ,  812  penetrate the sod and cut it into shorter lengths. The slots  806  allow the cross-cut knives  810 ,  812  to penetrate fully through and slightly beyond the full thickness of the sod on the third set conveyors during the cross-cut operation. As previously described, either the sod carrier  808  can be lowered onto the sod on third set conveyors  34 - 1 ,  34 - 2 , or the third set conveyors can be raised and pushed against the sod carrier  808 , or a combination of these two operations may occur. At this time, as previously described, the third set conveyors  34 - 1 ,  34 - 2  are stationary (this is possible because of the wide gap between successive strips of sod; see  FIG. 4   c ), thus allowing the sod strips on them to be cross-cut and picked up from the third set conveyors before the next set of sod strips arrives. 
   By way of example, the sod strip on each third set conveyor  34 - 1 ,  34 - 2  can be 48 inches long by 24 inches wide. When the 48 inch length is cut into three equal length pieces, each piece will be 16 inches long. Thus, after cross-cutting, each third set conveyor will carry three sod slabs, each sod slab being 16 inches by 24 inches, for a total sod dimension of 48 inches by 48 inches (divided into six easy to handle sod slabs). The entire set of six sod slabs can be picked up and deposited on a standard 48 inch by 48 inch pallet, using the sod carrier  808  in the same manner as sod carrier  94 , as described previously in this application. 
   As another example, the sod strip on each third set conveyor can be 48 inches long by 48 inches wide, and can be cut into four 24 by 24 inch pieces. Alternatively it can be cut into six 16 by 24 inch pieces. The third set conveyors can be divided into subconveyors as needed for the dimensions selected, and the cutting knives can be positioned as needed. 
   If desired, the sod strip on each of the third set conveyors  34 - 1 ,  34 - 2  can be divided into only two pieces (as previously described), or it can be divided into more than three pieces, by using additional cross-cut knives and third set conveyor subsections (not shown). 
   If the sod harvester  10  is cutting with only one cutting head  12 - 1 , then there will be only one third set conveyor  34 - 1 , divided (for example) into three subconveyors  34 - 1   a ,  34 - 1   b ,  34 - 1   c . In that case, the sod carrier  808  may be divided into two or three sections across its width, with the sod gripping clamps  130  of each section being separately operable (e.g. using separate actuating cylinders) to pick up sod. The three sections are indicated at  820 ,  822 , and  824  in  FIG. 56  (with the clamp mechanisms omitted for clarity). In that case, the sod carrier  808  can be positioned with section  824  over the third set conveyors  34 - 1  to cross-cut and pick up a strip of sod on those conveyors. The sod carrier  808  can then be raised and moved laterally one conveyor width in the direction of arrow  826 , to bring the center section  822  of the sod carrier  808  over the third set conveyor  34 - 1 . After the next strip of sod arrives and stops on the third set conveyor  34 - 1 , the sod carrier  808  is lowered so that its center section  822  cross cuts and picks up that strip of sod. The sod carrier  808  is then stepped once more in the direction of arrow  826  so that its third section  820  is located over the third set conveyor  34 - 1 , ready to pick up the next sod strip which arrives and stops there. When the sod carrier  808  has been filled in this manner, it is then moved over a pallet to deposit its sod on the pallet, as previously described. 
   While preferred embodiments of the invention have been described, it will be appreciated that various changes can be made, and such changes are intended to be included within the appended claims.