Abstract:
A self-propelled pipeline padding machine and a method for padding pipelines in ditches without damaging the pipeline prior to backfilling of the ditch. A spoils pile comprising dirt, various size rocks, and sand taken from the ditch during the digging thereof lie in a generally continuous pile along side the ditch from the excavation thereof. The machine includes an excavator having an arm with end bucket for scooping up material from the spoils pile on the opposite side of the ditch and placing it into frame mounted padding material sorter mounted to the front of the excavator. The separated padding material falls onto a laterally disposed retractable conveyor below the sorter which moves the padding material onto the pipeline in the ditch ahead of the excavator. The residual rocks and debris fall between the tracks of the excavator. The sorter can be tilted using hydraulic cylinders between the frame supporting the sorter and the undercarriage of the excavator. The padding material is deposited ahead of the excavator such that any rocks or debris inadvertently knocked or dropped into the ditch fall on already padded pipeline. The method includes depositing padding material onto a pipeline.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/094,485 filed by Express Mail on Jul. 29, 1998. 
    
    
     SPECIFICATION 
     BACKGROUND OF THE INVENTION 
     1. Field 
     The invention is in the field of machines and methods for padding pipelines, and more particularly to self-propelled padding machines and methods which utilize a single machine which scoops up the spoils, separates out padding material, and deposits such padding material on the pipeline. 
     2. State of the Art 
     When a long pipeline is to be laid such as a cross country gas or oil pipeline many miles in length, an excavator or other such device digs an elongate ditch into which the pipeline is to be subsequently laid. The dirt and rocks removed during the digging of the ditch, the spoils material, is typically dumped in a more or less continuous pile adjacent the ditch called the spoils pile. After the pipeline has been placed in the ditch, typically on sand bags or other supports, the pipeline is initially covered with only loose dirt and small rocks separated from the spoils material, called padding, which padding protects the pipeline when the residual material which remains after separating padding therefrom including rocks and other such material which is dumped on top of the pipeline to backfill the remainder of the ditch. This use of padding material is especially important to protect the outer coating applied to many modern pipelines which coating provides corrosion resistance thereto. 
     There are a number of different types of motorized pipeline padding devices such as for use such as for padding cross country gas and oil supply pipelines. A first type is disclosed in U.S. Pat. Nos. 5,120,433; 5,195,260; 5,363,574; and 5,430,962 all issued to Osadchuk. The pipeline padding machine comprises a tracked vehicle having a pair of vertically extending, ground level front projections which when driven against the spoils pile funnel the spoils material onto an elevator which carries the spoils material over the top and to the rear of the vehicle into a sorter. The sorter separates padding material from other residual material and deposits separated padding material onto a conveyor which laterally transports the padding material into the ditch onto the pipeline. The residual material such as rocks and other debris are deposited onto the ground behind the vehicle. Since the projections are mounted to the front of the vehicle but the padding material is deposited onto the pipeline at the rear of the vehicle, rocks are frequently knocked onto the unpadded portion of the pipeline causing damage thereto. Such padding machine cannot handle rocks of a larger size which can necessitate separating out such large rocks from the spoils pile prior to use thereof or the use of a separate excavator or similar machine to clear such large rocks therefrom when encountered. 
     A second type of pipeline padding machine which is separate from but attaches to a motorized vehicle is disclosed in U.S. Pat. Nos. 5,097,610; 5,261,171; and 5,479,726 all issued to Bishop. The pipeline padding machine attaches to the shovel of a tracked bulldozer with a pair of front projections which when driven against the spoils pile funnel the spoils material onto a screening belt which allows padding material to fall onto a longitudinally extending conveyor belt thereunder. The conveyor conveys the residual material into the shovel of the bulldozer or onto a separate laterally extending conveyor belt for subsequent backfilling of the ditch. The padding material on the conveyor belt drops padding material onto a laterally extending conveyor belt which drops the padding material onto the pipeline adjacent the rear of the padding machine. This version suffers from the problem of the padding machine of Osadchuk of damaging the pipeline by inadvertently knocking rocks onto the unpadded portion of the pipeline. An alternate version of the padding machine further includes a generally longitudinally forward extending conveyor belt which conveys the padding material from the laterally extending conveyor belt onto the pipeline slightly ahead of the front projections presumably in an effort to solve such problem. Such padding device still suffers from the other problem of the padding machine of Osadchuk of not being able to handle large rocks. A third type of pipeline padding machine is disclosed in U.S. Pat. No. 5,084,991 issued to Cronk, Jr., which mounts to a tracked bulldozer in place of the shovel and which can be moved vertically and tilted as normally done with the shovel replaced thereby. Such padding machine comprises a longitudinally disposed drum in a frame attached to the bulldozer which drum is rotationally powered. The exterior of the drum includes a screen to pass padding material but not larger spoils material and a plurality of paddles to engage the spoils material and propel such spoils material against the screen. A laterally extending conveyor belt extends outwardly from inside the drum to receive padding material and convey such padding material laterally onto the pipeline in the ditch. The conveyor is disposed behind the front portion of the drum and cannot accept medium sized and larger rocks, therefore suffering from the aforementioned disadvantages of the other prior art padding machines. 
     Other pipeline padding machines include a pipeline padding machine comprising a sorter which attaches to the side of a tractor by means of a frame and which extends over the ditch which is disclosed in U.S. Pat. No. Re. 34,289 issued to McClain et al. The sorter must be loaded by a separate bulldozer, excavator, or other such device. A similar type padding machine for attachment to the side of a tractor is disclosed in U.S. Pat. No. 4,955,756 issued to Klamar. In U.S. Pat. No. 4,616,957 issued to Burrows et al. is a pipeline padding machine which comprises a sorter and conveyor which mounts to a tracked bulldozer in place of the shovel similarly to that of Cronk, Jr. and which can be loaded by a dump truck in front of the padding machine. A motorized pipeline padding machine having a laterally disposed front feed screw, a system of conveyors, and a sorter is disclosed in U.S. Pat. No. 4,912,862 issued to Bishop et al. A longitudinally forwardly extending conveyor deposits padding material onto the pipeline adjacent the feed screw. 
     There are various types of sorters known in the art for separating suitable padding material such as dirt and small rocks from larger material not suitable for padding pipelines such as larger rocks, clods of dirt, and other such residual material which might damage an unpadded pipeline. Examples of such include wobbler type sorters which have a plurality of spaced, laterally disposed oblong cross-section wobbler members which rotate ninety degrees out of phase with adjacent wobblers to agitate and transport spoils material while allowing suitable padding material to fall therebetween. A second type of sorter is a vibratory type sorter which typically utilizes a vibrating frame having stacked from top to bottom a grizzly having plurality of spaced bars to exclude larger rocks and other material, and one or more screens which pass only spoils material of a predetermined size so as to pass only suitable padding material through the finest thereof. 
     SUMMARY OF THE INVENTION 
     The invention comprises a self-propelled pipeline padding machine and a method for padding pipelines without damaging the pipeline by the detrimental impact of rocks or other such material. The pipeline padding machine comprises a motorized vehicle, a sorter means attached to an end of the vehicle such as by a frame means, a loading means attached to the vehicle of such configuration to permit scooping up spoils material from the spoils pile on the same side, from the opposite side, or from both sides of the ditch from the padding machine and for dumping the spoils material into the sorter means, and a chute or conveyor means supported by the frame means which receives padding material from the sorter means and which transports the padding material into the ditch to the side and generally ahead of the vehicle such that rocks and other such debris inadvertently knocked into the ditch such as during the scooping of spoils material falls on the portion of the pipeline which has already been padded. The sorter preferably can be positioned vertically, such as by tilting, using an elevating means so as to adjust for the height of the surface of the ground. 
     The method of the invention for padding pipelines disposed in an elongate ditch with the spoils material removed during the digging thereof being in an elongate, generally continuous spoils pile or a series of spoils piles alongside the ditch, wherein a portion of the pipeline is unpadded and a portion of the pipeline is already covered with padding material. The method comprises the steps of (a) scooping up spoils material from the spoils pile adjacent the padded portion of the pipeline, moving such spoils material to a sorter, and depositing the spoils material into the sorter, (b) separating padding material from the residual material such as rocks and other debris inside the sorter, which is positioned adjacent the padded portion of the pipeline, (c) conveying the separated padding material from the sorter into the ditch on top of the unpadded portion of the pipeline and slightly overlapping the padded portion of the pipeline immediately adjoining the unpadded portion of the pipeline. Such steps are conducted concurrently, sequentially, or in the order required to fit the particular pipeline padding job or application, while moving continuously and/or intermittently alongside the ditch travelling generally parallel to the ditch in a predetermined direction so as to remain adjacent the padded portion of the pipeline such that rocks and/or other such materials which could damage the pipeline which are inadvertently knocked into the ditch during padding thereof primarily land on the padded portion of the pipeline so as to not damage the pipeline and any protective coating thereon. 
    
    
     THE DRAWINGS 
     The best mode presently contemplated for carrying out the invention is illustrated in the accompanying drawings, in which: 
     FIG. 1 is a side elevational view of the pipeline padding machine of the invention; 
     FIG. 2, a top plan view of the pipeline padding machine showing the relationship between the spoils pile, the scooping bucket, the conveyor, and the padded pipeline during operation; 
     FIG. 3, a fragmentary top plan view of the lifting mechanism; 
     FIG. 4, a view taken on the line  4 — 4  of FIG. 3 showing the operation of the lifting mechanism; 
     FIG. 5, a fragmentary front elevational view of the conveyor and laterally movable frame; 
     FIG. 6, a top plan view of a wobbler sorter; 
     FIG. 7, a longitudinal vertical sectional view taken on the line  7 — 7  of FIG. 6 showing the chain interconnecting the sprockets of the wobblers, the relationship to the funnel and the conveyor, and the mountings for the wobbler sorter; 
     FIG. 8, a longitudinal vertical sectional view taken on the line  8 — 8  of FIG. 6 showing drive motor and the sprocket and chain drive for the wobblers; 
     FIG. 9, a top plan view of a vibratory sorter; 
     FIG. 10, a longitudinal vertical sectional view taken on the line  10 — 10  of FIG. 9 showing the spring mounting of the vibratory sorter, the eccentric disk, and housing therefore; 
     FIG. 11, a longitudinal vertical sectional view taken on the line  11 — 11  of FIG. 9 showing the hydraulic drive motor for the vibratory sorter; 
     FIG. 12, a top plan view of a variation of the vibratory sorter which utilizes a perforated plate; 
     FIG. 13, a front perspective view of the pipeline padding machine; and 
     FIG. 14, a rear elevational view of the pipeline padding machine. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2 therein is shown the pipeline padding machine of the invention. Padding machine  20  comprises a motorized vehicle, preferably an excavator  23  of the type having a rotatable body  26  mounted on a tracked undercarriage  29 . A loading means comprising a hydraulically actuated extendible lifting arm  32  extends from and is pivotally mounted to a platform structure  35  of rotatable body  26 . Lifting arm  32  includes a long arm  38 , a short arm  41  pivotally mounted thereto, and a bucket  44  pivotally mounted thereto. Long arm  38  is pivotable vertically by means of a pair of hydraulic cylinders  47 . Short extension arm  41  is pivotable by means of a hydraulic cylinder  50 , and bucket  44  is pivotable by means of a hydraulic cylinder  53 . The respective hydraulic cylinders  47 ,  50 , and  53  are powered by means such as an integral engine-driven hydraulic pump unit (not shown) mounted on platform structure  35  in an engine housing  57  of rotatable body  26 . A cab  60  mounted on platform structure  35  encloses the operator and controls (not shown) for the excavator  23 . Body  26  is mounted to and rotates on a main pivot  63  which is mounted to undercarriage  29 . Extendible lifting arm  32  can reach spoils material and other materials anywhere within the reach thereof whether ahead of, behind, or beside excavator  23 . 
     Undercarriage  29  is preferably modified so as to be of a longer overall length than a conventional excavator so as to provide greater stability when a sorter means such as a wobbler sorter  66  and a conveyor means comprising a conveyor  67  are mounted thereto by an elevating means comprising an elevation mechanism  69 . Such lengthening is designated “A” and is typically about six feet depending on the weight and placement of the sorter (FIG.  1 ). Such lengthening of undercarriage  29  helps to maintain an even front-to-rear balance of excavator  23  to further maintain stability thereof, particularly important in padding work done on up and down slopes and on side slopes. Undercarriage  29  comprises an extended main frame  72  to which main pivot  63  is connected and a pair of continuous cleated tracks  75  each are guided by and ride on a plurality of bogey wheels  78  connected to respective elongate side members  81 ,  82 ,  83 , and  84  of main frame  72  and are powered by at least one of a pair of cog wheels  87  powered such as by hydraulic motors (not shown) by means of the engine driven hydraulic pump unit (not shown). Each of tracks  75  can be driven in a forward or reverse direction or stopped independently of the other of tracks  75  which allows maneuvering of excavator  23  by driving one or both of tracks  75  so as to skid tracks  75  and rotate excavator  23  and/or move in a forward or reverse direction. 
     Referring to FIGS. 3 and 4, the frame means comprises a main frame  90  having a pair of lifting arms  93  and  96  which have respective I-beam portions  99  and  102 , and necked down portions  105  and  108 , and main pivot brackets  109 . A pair of triangular bumper arms  111  and  114  extend downwardly from lifting arms  93  and  96 , respectively. Upper, middle, and lower cross members  117 ,  120 , and  123 , respectively, connect lifting arms  93  and  96 , and bumper arms  111  and  114  together. Main frame  90  is pivotally mounted to side members  82  and  83  of main frame  72  by means of main pivot brackets  132  connected thereto and pins  135 . 
     The elevation means comprises elevation mechanism  69  which comprises a pair of triangular cams or plates  138  are positioned on respective sides of each of necked down portions  105  and  108  and are pivotally mounted to frame members  82  and  83  of main frame  72  by means of secondary pivot brackets  139  and pins  141 . A pair of links  142  connect pairs of plates  138  and necked-down portions  105  and  108  of lifting arms  93  and  96  by means of pins  143 . A pair of dual action hydraulic lift cylinders  144 , each having a body  147  and a rod  150  with rods  150  connected to respective pairs of triangular plates  138  by means of pins  153 . Bodies  147  of cylinders  144  are pivotally connected to respective side members  82  and  83  of main frame  72  by means of respective brackets  156  and pins  159 . By extending cylinders  144 , triangular plates  138  rotate such that links  142  downwardly pull necked-down portions  105  and  108  of lifting arms  93  and  96  which pivot about pins  135  at main pivot brackets  132  vertically lifting sorter  66 . 
     Referring to FIG. 5, the conveyor means comprises conveyor  67  which comprises a movable frame  186  and a motorized belt assembly  189 . Frame  186  comprises a pair of parallel C-beams  192  and  195  interconnected by a plurality of cross members  198 . Frame  186  is movably connected to main frame  90  by means of a plurality of rollers  201  connected to cross members  120  and  123  by means of a plurality of pins  204 . C-beams  192  and  195  are movable on rollers  201  to extend conveyor  67  over a ditch (not shown) during use and retract to a laterally centered position relative to excavator  23  for periods of non-use for a more compact unit. Such movement is by means of a pair of hydraulic cylinders  207  each having a body  210  and a rod  213 . Bodies  210  of cylinders  207  extend through and are attached to bumper arms  111  and  114  of main frame  90 . Rods  213  of cylinders  207  are each pivotally connected to respective C-beams  192  and  195  by means of brackets  216  and pins  217 . When hydraulic cylinders  207  extend, frame  186  and belt assembly  189  move laterally outwardly to a working position and when hydraulic cylinders  207  retract, frame  186  and belt assembly  189  move laterally inwardly to a more compact, stowed position. 
     Belt assembly  189  comprises a plurality of rollers  219  rotatably mounted on axles  222  with an elongate rubberized cloth belt  225  extending therearound. One of rollers  219  is driven by means of a hydraulic motor  228  so as to drive belt  225  to convey padding dirt (not shown) laterally from an outlet  231  of a funnel  234  under sorter  66  to a ditch (not shown). A deflector  237  can be attached to the distal ends of C-beams  192  and  195  by means of a bracket  240  to downwardly deflect padding dirt horizontally exiting belt  225 , particularly at higher belt speeds. 
     Referring to FIGS. 6,  7 , and  8 , a first version, wobbler type sorter  66  includes a shell  243  having an upper hopper portion  246  and a lower body portion  249  which is attached to lifting arms  93  and  96  for movement therewith. A rock exit opening  252  in upper hopper portion  246  and lower body portion  249  is defined by a pair of inwardly extending flaps  255  and  258 . Lower body portion  249  connects with an inlet  261  of funnel  234  so as to direct padding into funnel  234  and onto conveyor  67 . A hydraulic motor  264  is mounted by means of a bracket  267  to lifting arm  93 . A shroud  268  covers hydraulic motor  264 . Sorter  66  includes a wobbler feeder  270  includes a frame  273  which fits within and is attached to upper hopper portion  246  such that rocks and dirt are funneled by upper hopper portion  246  into wobbler feeder  270 . Wobbler feeder  270  further includes a plurality of parallel wobblers  276 , each oblong in cross-section with a plurality of ribs  278  on the exterior thereof and rotatably mounted to frame  273 . Wobblers  276  are oriented such that adjacent wobblers  276  are rotated ninety degrees relative to each other such that a constant gap distance “G” is maintained during rotation thereof (FIG.  6 ). Each wobbler  276  has a sprocket  279  which are rotated and maintained in the proper orientation by means of a continuous chain  282 . Hydraulic motor  264  has a sprocket  285  and wobbler feeder  270  has a sprocket  288  which are interconnected by means of a continuous chain  291  such that wobblers  279  are driven in a synchronous fashion by hydraulic motor  264 . Rocks and dirt are loaded into upper hopper portion  246  onto wobbler feeder  270 . As wobblers  276  rotate the rocks and dirt are agitated and fed toward rock exit opening  252  with padding material comprising dirt, small rocks, and other such appropriately sized material falling through gaps “G”, through lower body portion  249 , through funnel  234  onto conveyor  67  for lateral transport to the ditch (not shown). Rocks and other such debris too large to pass through gaps “G” falls onto the ground through rock opening  252  between the tracks  75  of excavator  23  for later back filling of the ditch over the padded pipeline (not shown). While sorter  66  is shown with wobbler sorter  270  in a tilted position therein, a sorter such as sorter  66  can be designed such that wobbler sorter  270  is in a horizontal position with wobblers  276  moving the spoils material through residual material outlet  252 . 
     Referring to FIGS. 9-11, a second version, vibrator type sorter  66 A includes a shell  243 A having an upper hopper portion  246 A and a modified lower body portion  249 A, which lower body portion  249 A includes pairs of upper spring mounting brackets  294  on opposite sides thereof each of which correspond with a lower spring mounting bracket  297  of modified lift arms  93 A and  96 A. A compression spring  300  fits between each pair of upper and lower spring mounting brackets  294  and  297 , respectively, such that modified shell  243 A “floats” relative to a modified main frame  90 A but still elevates and lowers therewith. Residual material exit opening  252  in upper hopper portion  246 A and lower body portion  249 A is defined by inwardly extending flaps  255  and  258 . Lower body portion  249 A connects with inlet  261  of funnel  234  so as to direct padding into funnel  234  and onto conveyor  67 . Hydraulic motor  264  is mounted by means of bracket  267  to a lifting arm  93 A. Sorter  66 A includes a vibrator assembly  301  comprising a vibrator shaft  303  coupled at one end thereof by means of flexible coupling  306  to hydraulic motor  264  and at the opposite end thereof supported by a journal bearing  309  connected to a lifting arm  96 A. An eccentric weight disk  312  is connected to vibrator shaft  303 , with the longitudinal axis  315  of vibrator shaft  303  offset from the center  318  of weight disk  312  by a distance “D”. Therefore, as hydraulic motor  264  drives eccentric weight disk  312  through coupling  306  and shaft  303 , vibration is induced due to offset distance “D” which vibration is transferred through journal bearing  309  to lift arm  96 A causing main frame  90 A to vibrate (FIGS.  9  and  10 ). Such vibrations are transferred through upper and lower spring mounting brackets  294  and  297 , and springs  300  to sorter  66 A. The spring rates of springs  300 , the weight of sorter  66 A, the flexibility of main frame  90 , the weight and offset “D” of eccentric disk  312 , and the speed (revolutions per minute) of hydraulic motor  264  may be designed such that sorter  66 A oscillates at a desired steady frequency. Sorter  66 A further comprises a grizzly  321  comprising a plurality of elongate, tapered, T-shaped cross-section grizzly bars  324  supported by a plurality of support bars  327  attached to upper hopper portion  246 A. Gaps  330  between grizzly bars  324  increase in width moving toward rock opening  252 . Likewise, grizzly  321  slopes downwardly toward residual material exit opening  252  such that spoils material moves in that direction. A screen assembly  333  has a frame  336  attached at the edges thereof to upper hopper portion  246 A, extending below and generally parallel to grizzly  321 , and includes a screen mesh  339  having voids of the maximum size dirt, rocks, and other such materials desired to pass through as padding. Rocks and dirt are loaded into upper hopper portion  246 A onto grizzly  321 . As sorter  66 A vibrates, the rocks, dirt, and other such spoils material are agitated and move toward rock exit opening  252  with appropriately sized dirt, rocks, and other such material falling through gaps  330  onto screen assembly  333  and continuing toward residual material exit opening  252 . Rocks, dirt, and other such material smaller than the voids in screen assembly  333  fall through screen mesh  339 , through body portion  249 A, through funnel  234  onto conveyor  67  as padding material for lateral transport to the ditch (not shown). Rocks, dirt, and other such material too large to pass through gaps  330  fall onto the ground through residual material exit opening  252  between the tracks  75  of excavator  23  for later back filling onto the padded portion of the pipeline (not shown). Likewise, rocks, dirt, and other such material small enough to pass through gaps  330  of grizzly  321  but too large to pass through the voids in screen mesh  339  fall to the ground through rock opening  252  between the tracks  75  of excavator  23  for later back filling onto the padded portion of the pipeline. Alternatively, such rocks which pass through grizzly  321  but not through screen assembly  333  can be delivered to the already padded pipeline by means of a second conveyor (not shown) which is generally parallel to but rearward of conveyor  67 , the padding protecting the pipeline from the larger rocks. 
     Referring to FIG. 12, grizzly  321  can be replaced by a thick, perforated plate grizzly  342  attached at the edges thereof to an upper hopper portion  246 B of a modified sorter  66 B, being typically of about one-inch thick steel having a plurality of holes therethrough such as hexagonal holes  345 . Holes  345  are of such size as to pass only rocks of a desired size onto screen assembly  333 , with rocks and other such debris too large to pass through holes  345  which falls onto the ground through residual material exit opening  252  between the tracks  75  of excavator  23  for later back filling onto the padded portion of the pipeline. 
     Referring to FIGS. 2,  13 , and  14 , therein is shown the padding machine  20  in operation as typically used to pad a pipeline. Padding machine  20  is positioned adjacent a ditch  348  in which a pipeline  351  is disposed, typically on a support structure such as sand bags (not shown). Padding machine  20  typically travels on a generally smooth first side  354  of ditch  348  with a second side  357  having a spoils pile  360 . As such, extendible arm  32  of excavator  23  can reach across ditch  348  to scoop up a load of spoils material from spoils pile  360  and load such spoils material into sorter  66 , without necessitating travelling on top of spoils pile  360 . Padding material  363  separated from the spoils material by sorter  66  falls onto conveyor  67  and is conveyed onto pipeline  351  generally ahead of excavator  23  forming a padded portion  366  which remains adjacent padding machine  20  during normal single direction operation in the forward travel direction. The unpadded portion  369  of pipeline  351  remains generally ahead of excavator  23  such that any spoils or other material, particularly rocks, which may inadvertently be knocked onto pipeline  351  most likely will fall onto padded portion  366  rather than unpadded portion  369  with such padding material thereon protecting pipeline  351  from damage. As shown best in FIG. 2 (phantom lines), the placement of sorter  66  and conveyor  67  relative to extendible arm  32  on excavator  23  is such that the reach of extendible arm  32  is maintained behind unpadded portion  369  during the normal operation of padding machine  20 . 
     Many variations of the pipeline padding machine and method of the invention can be made without departing from the inventive concept thereof. Examples include but are not limited to the motorized vehicle and loading means can be other than an excavator with extendible arm, for example a wheeled vehicle with an extendible arm or other loading means. A pair of powered or towed vehicles can be used, with the loading means on one vehicle and with the sorting means and conveying means on the other vehicle. A wheeled vehicle having an extendible arm or other such loading means can be used. The excavator can be replaced by a wheeled vehicle having a loading means such as an extendible arm. The conveyor means can be other than a belt type such as a downwardly angled chute with or without vibration means to maintain the flow of padding material into the ditch. The wobbler sorter can be disposed generally horizontally rather than at an angle using the wobblers to move the spoils material to the residual material exit opening. The sorters, particularly the vibratory type sorters, can be pivotally mounted to the lifting arms to allow pivotal movement during use such as for self-leveling thereof. A vibratory sorter can used which uses an offset or eccentric shaft rather than a separate rotating eccentric weight disk. The sorter can be other than of the vibratory or wobbler type with virtually any type of sorter possible now known or developed in the future. 
     Whereas this invention is here illustrated and described with reference to embodiments thereof presently contemplated as the best mode of carrying out such invention in actual practice, it is to be understood that various changes may be made in adapting the invention to different embodiments without departing from the broader inventive concepts disclosed herein and comprehended by the claims that follow.