Abstract:
Portland Cement Concrete with steel reinforcement mats or rods used in airport runways, highways, and other objects need to have the cement broken up for recycling or disposal and the steel mat reused or the steel recycled. The pavement removal machine lifts the concrete off a roadbed and places it on an anvil. A hammer then cracks the concrete and breaks it into small pieces, which fall away from the reinforcing steel. The concrete and the steel are then recycled. The pavement removal machine has legs which are moveable between a road working position and a transport position and can translate the frame of the machine up and down. The hammers can be gravity drop or powered. The steel can be cut into sections as the pavement is continuously torn up at a rate of about 1 lane mile per day.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a machine for pulverizing concrete sheets or slabs, and more particularly to a machine for pulverizing concrete roadbeds having reinforcing steel therein, where the machine is moved along the roadbed during the pulverizing operation. The machine recycles the roadbed by reducing it to concrete aggregate and scrap steel. It accomplishes in one operation that now requires six steps in removal of deteriorated concrete roads. 
   2. Description of Related Art 
   The replacement of concrete roadways creates a unique and troublesome disposal problem whenever large and bulky concrete slab or sheet structures must be removed from the work site. Such large structures are unsuitable for disposal in landfills unless broken up into small pieces because they tend to create voids underground which prevent adequate filling and compaction. While air and hydraulic hammer machines have been developed to break up such concrete structures into smaller pieces, these machines are particularly unsuitable when the concrete has reinforcing steel embedded therein. Even after hammering, concrete tends to adhere to the steel, resulting in tangled steel and concrete debris, which is difficult to move and dispose of. The reinforcing steel itself is usually not reclaimable because of the exceedingly high concrete content that adheres to it. This material is typically trucked to remote disposal sites for inadequate disposition, for no better disposal or recycling program is known for such material. The hauling of this material to remote sites adds to the cost of reconstruction, and the loss of the steel and concrete material for recycling creates a needless economic loss to the owner of the material. 
   In the reconstruction of roadbeds the old concrete roadbed is typically hammered by means of machines to reduce the size of the concrete and steel fragments to manageable proportions, and these fragments are hauled away. The new roadbed is then filled and graded, and new concrete and reinforcing steel are applied to create a new road. A significant proportion of the total cost of building such a road is attributable to the cost of removing the old roadway, and no significant return is achieved through any recycling process. 
   Current road removal of deteriorated concrete roads involves a multiple step process for removing the old concrete road. First the concrete road is cracked such as by a plurality of jackhammers, then a “rhino horn” device lifts up the cracked roadbed. Then the steel rods or mesh is sawed or burned through to create sections of roadbed. The sections can be hauled to a landfill or a crusher caravan can first crush the concrete roadbed sections to a primary size aggregate and then a secondary crusher reduces the size of the aggregate to a desired size and the steel rods or mesh can be separated. Each of the above steps requires a different piece of equipment in a caravan traveling down the road and is labor intensive. What is needed is a machine to process old steel reinforced concrete roadbeds into concrete aggregate and recyclable scrap steel by continuously pulling up the roadbed, reducing the concrete recyclable concrete aggregate and separating out the steel mesh or rods as the machine travels along the road. 
   In the applicant&#39;s prior U.S. Pat. No. 4,309,126 a machine for separating concrete from steel for tearing up a roadbed and recycling it was presented. The machine used a wedge to pick the concrete pavement off the roadbed and lift it to an anvil for presentation to hammers, which removed the concrete from the steel reinforcing rods however the steel reinforcing rods would have to be disassembled for recycling which was labor intensive. Further the reinforcing rods were forced up over the driver on top of the machine, which required a ramp and a considerable amount of energy to force the steel rods up and over the top of the machine. There were many drawbacks to having the steel passing over the top of the machine such as inhibiting turns, weight, limitations of machine configuration due to height and possible safety issues. Further, the tracks on the machine were aft of the wedge, which is not ideal. It is better to pull the wedge under the pavement than to push it. Further the tracks were in a fixed position which made it harder to transport the machine since it is necessarily wider than a lane of a roadway and was longer than wide. The hammers in the applicant&#39;s prior machine had a small footprint and the hammers had to traverse the surface of the road for the foot of each hammer to impact on the entire surface of the pavement. 
   SUMMARY OF THE INVENTION 
   The pavement removal machine has a main body which is narrow such that it can be turned sideways for transport on a trailer over roadways to get to different sites. The legs of the pavement removal machine are supported by arms which can pivot to change the machine configuration from the road working mode to the transport mode. Further the legs can be moved up and down to lift the machine onto or off of a trailer and to adjust the wedge and anvil position relative to the pavement. The pavement removal machine in its operational purpose lifts the pavement from the roadbed by the tracks on the front legs pulling the wedge and anvil under the pavement and lifting it up for the hammers to pulverize the concrete while it rests on the anvil and breaks most of the concrete up into small pieces which fall away from the steel reinforcing rods in the pavement. The concrete is then transported by conveyor belts to the side of the road or onto trucks on the side of the pavement removal machine for transport to a concrete recycling facility. The steel is cut into sections of 4-5 feet lengths and placed in a container aft of the conveyors and the containers can be easily removed and replaced for hauling loaded containers to a scrap recycling facility to reuse the steel. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide an easily to assemble and disassemble, transportable design for a pavement removal machine. 
   It is an object of the invention to strip concrete by shock fracture from the steel reinforcing rods or mesh and cut the rods into manageable lengths on the pavement removal machine and store the cut lengths of steel in a container towed by the pavement removal machine. 
   It is an object of the invention to allow the pavement removal machine to be quickly readied to tear up and recycle reinforced concrete pavement after it is transported to the site. 
   It is an object of the invention to allow the pavement removal machine to be quickly and easily loaded on to a trailer for transport. 
   It is an object of the invention to separate the pavement removal machine into a tractor component, a wedge and anvil component and conveyors for ease of transporting the pavement removal machine by sections. 
   It is an object of the invention to quickly remove and recycle pavement. 
   It is an object of the invention to provide hammers which can quickly shock fracture concrete for the lane width of the road. 
   It is an object of the invention to increase the efficiency of pavement removal machines. 
   Other objects, advantages and novel features of the present invention will become apparent from the following description of the preferred embodiments when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of the pavement removal machine recycling a roadbed. 
       FIG. 2  is a front right hand perspective view of the pavement removal machine. 
       FIG. 3  is a top view of the pavement removal machine with the legs rotated for transport on a flatbed trailer. 
       FIG. 4  is an exploded view of a hammer. 
       FIG. 5  is a perspective view of an alternate embodiment of the pavement removal machine lifting and cracking the roadway on the anvil. 
       FIG. 6  is a side view of the pavement removal machine of  FIG. 5  cracking the roadway only without use of an anvil. 
       FIG. 7  is a side view of the pavement removal machine of  FIG. 5  for producing concrete aggregate and recycling scrap steel and uses a 2-crawler tractor for certain operations such as exits and entrances. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The pavement removal machine  10  is shown generally in  FIGS. 1-3 . The pavement removal machine  10  is designed to take pavement  20  composed of concrete  22  with steel reinforcement rods or steel mesh  25  therein and lift the pavement  20  off the roadbed by use of a wedge  40  which goes under the pavement  20  and lifts it up as the pavement removal machine  10  is propelled forward. The concrete  22  in the pavement  20  begins to crack as it is forced upward by the wedge  40 . The concrete  22  is pushed upward along the wedge  40  until it reaches an anvil  42  at the rear of the wedge  40 . The anvil  42  supports the concrete  22  with steel rod  25  reinforced pavement  20  such that a hammer  50  can impact on the concrete  22  which is between the hammer  50  and the anvil  42 . The hammer blows first crack the concrete  22  by shock and then separates the concrete into small pieces, which are pushed forward and falls onto a discharging conveyor, as best seen in  FIGS. 3 and 7 , onto a conveyor belt  60  and lifted unto a transverse conveyor belt  62  and moved to the side of the road or placed on a conveyor  64  for lifting into a truck  66  for hauling the concrete  22  away. The concrete  22  can then be recycled for use in a concrete mixture for the new roadway at the site or for use at another location. The concrete  22  will largely be debonded, in response to shock, from the steel reinforcing rods  25  and the steel rods or mesh will be taken up by saw table  70  and cut into sections by saw  75 . The sections  125  of cut reinforcing will then fall into container  77  which will be hauled away to a steel recycling center to reuse the steel. 
   In the embodiment shown in  FIGS. 1-3 , the pavement removal machine  10  has moveable legs  30  have pistons  34  which can be raised up and down to raise or lower the main body  15  of the pavement removal machine  10  such that it can be raised to put the main body  15  on a flat bed trailer  140  and then the pistons  34  raised for transporting the pavement removal machine  10  to another location. The arms  35 , which support the legs  30  rotate on pivots  135  and can be rotated 90 degrees such that the legs  30  can be aligned for transport on the flatbed trailer  140  as shown in  FIG. 3 . When the pavement removal machine  10  is transported to a site for work the arms  35  are extended such that the legs  30  straddle the pavement  20  to be torn up and recycled. The pistons  34  on legs  30  can then be raised so that the transport trailer  140  can be removed and then the pistons  34  on legs  30  can be lowered to put the pavement removal machine  10  in position to work on the pavement  20  and to maintain proper level of engagement with the pavement  20  to be processed. 
   The hammers  50  and the conveyors  62  and  64  may be removed from the pavement removal machine  10  for transportation since the hammers may protrude too high and the conveyors  62  and  64  may be too wide for the trailer  140 . The hammers  50  and conveyors  62  and  64  may be easily reassembled on the pavement removal machine when it arrives at a new site. Alternatively, as shown in  FIG. 4 , the hammer assembly  50  may be pivoted on mounting hinge assembly  101  to tilt the hammer mass  51  down for transport or for maintenance. 
   The conveyor  64  can be pivoted to different positions to load trucks or for transporting the pavement removal machine  10  with the conveyor in a position parallel to the length of the trailer  140 . 
   Legs  30  have pistons  34  which are raised or lowered by hydraulic cylinders  36 . The legs  30  are supported by pods  38  connected to pistons  34 . The pods  38  have hydraulic powered tracks  32  thereon to propel the pavement removal machine  10 . The pods  38  can be steered by use of steering pistons  33  connecting the arms  35  to the outside of the housing  130  for legs  30 . The steering pistons  33  can rotate the pods  38  as shown by arrows  133  to steer the pavement removal machine  10 . The track pods  38  can also be individually controlled to augment steering. 
   The legs  30  can also be adjusted to locate the tracks  32  in position relative to the wedge  40  and anvil  42  such that the wedge can force the pavement  20  upward as all four tracks  32  push and pull the pavement removal machine  10  forward thus lifting the pavement  20  on the wedge  40 . Hydraulic motors (not shown) in the track pods  38  power the tracks  32  for propelling the pavement removal machine  10 . The tracks  32  may be individually controlled for skid steering. 
   The wedge  40  and anvil  42  may have many different designs. As best seen in  FIG. 2  the leading edge  44  of the wedge  40  can have a pointed portion and may support a plate thereover. The wedge  40  has a plate thereover for the pavement to slide on as it is forced upward. The anvil  42  has a steel plate thereover such that it forms a solid surface on which the pavement  20  may rest as it receives hammer blows from hammer  50  to break up the concrete  22 . The anvil  42  must be strong enough to absorb the hammer blows and reflect the energy in the blows back through the concrete  22  so as to help break up the reinforced concrete pavement  20 . The hammer blows are sequenced such that the anvil  42  will respond to one blow at a time. 
   The leading edge  44 , wedge  40  and anvil  42  are all connected by pivots such that they can form different angles relative to one another. It may be advantageous to have the leading edge  44  pointed at a different angle than the wedge  40  to have a smaller angle of incidence with the base of the pavement  20  and such that the points of the leading edge  44  are not digging into the ground under the pavement. The wedge portion  40  may be at an angle to raise the pavement  20  a small distance without using too much energy and the anvil  42  may be at an angle to the wedge  40  to help crack the pavement  20  at the interface thereof and to hold the pavement perpendicular to the travel of the hammers  50  such that the hammer blows are perpendicular to the surface of the pavement for maximum effect. The leading edge  44 , wedge  40  and anvil  42  may be separately replaced due to differing wear rates. 
   The anvil  42  is not attached to the machine frame directly but rests or floats on the road sub-base but is guided fore and aft by linkages to pull the wedge  40  and anvil  42 . This arrangement limits the transmittal of shock that is not attenuated by the fracturing process. The linkage hinges employ rubber rings between bearing races. 
   The hammers  50  may be either gravity drop, hydraulic assisted, or pneumatic assisted hammers. The pneumatic assisted hammers provide more impact than gravity hammers since the pneumatic energy added will accelerate the hammers to provide more impact at strike. The hammers  50  may have a mass of up to about 5500 kilograms (12,125 pounds). 
   In a preferred embodiment as show in  FIG. 4  the hammer  50  is shown as a hammer assembly. The hammer mass  51  has a pair of arms  52  connected at the top by a header block  56  and at the bottom by a hammer head  58  with teeth  59 . The hammer mass  51  has an angled face  90  along the inside facing edges of arms  52  for engaging the angled face guide plate plastic wear strips  92  on the outer guide plate  80  and the mounting guide plate  82 . The guide plates operate on the inside perimeter edges of the arms  52  to keep the hammer aligned straight up and down relative to the guide plates. The angled face  90  along the arms  52  and angled face guide plate plastic wear strips  92  on the outer guide plate  80  and the mounting guide plate  82  are made of a high density plastic which provides smooth slippery surfaces to slide along as the hammer mass slides up and down relative to the guide plates  80 ,  82  while holding the hammer in place to limit side to side movements which can result in a reduction in the force applied to the concrete. The length of the angled face guide plate plastic wear strips  92  on the guide plates  80 ,  82  provide for stably holding the hammer mass  51  in place as it slides up and down on the guide plates  80 ,  82 . The angled face guide plate plastic wear strips  90 ,  92  are preferably at 45 degrees to the face and side of the hammer mass. 
   The outer guide plate  80  has slots for spacers  87  for guide plate lugs  85  on the guide plate spacers  81  of mounting guide plate  82  thus locking the guide plates  80 ,  82  together to form a guide for stabilizing the hammer mass  51  as it moves up and down. The guide plate spacers  81  provide for the guide plates  80 ,  82  to surround the cylinder  53  and the piston  84 , which is centered within the hammer mass  51 . The piston  84  is connected to the hammer mass  51  at the hammer head  58  by a rod connection  110  passing through an aperture in the hammer mass  51  and the base of the piston  116 . The pin has a rubber collar  112  to help reduce shock and a retainer  114 , which secures the rod connection  110  in place. A cushion  118  can also be used on top of the piston base  116  to help reduce shock between the piston  84  and the hammer mass  51 . 
   The hydraulic cylinder  53  and the piston  84  are centered in the hammer mass  51  which is centered in the guide plates  80 ,  82  to provide for forces straight up and down without wasted side to side or front and back motions to decrease the efficiency of the hammer. The center of mass of the hammer mass  51  is in line with the center of the hydraulic cylinder  53  and piston  84  so that the mass will tend to not tilt or twist the hammer assembly  50  during use which wastes energy and contributes to vibrations and wear. 
   The hydraulic cylinder  53  has cylinder mounting collars  86  mounted thereon for attaching the outer guide plate  80  thereto. The outer guide plate  80  has apertures  89  for engaging the cylinder mounting collars  86  and cylinder mounting shock absorbers  88  preferably made out of rubber for surrounding the cylinder mounting collars  86  and being between the cylinder mounting collars  86  and the aperture  89 . A cover plate  83  keeps the cylinder mounting shock absorbers in place. Hydraulic line  99  connects from a hydraulic pump (not shown) to hydraulic valve  98  on the hydraulic cylinder  53  to power the hammer retract. 
   In one mode of operation the hydraulic cylinder  53  is used to raise the piston  84  up into the cylinder  53  and the hammer mass  51  is then allowed to drop by gravity and hit the concrete  22  to be broken up. The teeth  59  at the base of the hammer head  58  of the hammer mass  51  hits the concrete and first cracks and then breaks up the concrete. The teeth  59  being spaced apart allows space along the surface of the concrete for breaking up the concrete and increasing the shock at the point where the teeth impact the concrete. 
   The concrete to be broken up is placed on an anvil  42  to increase the shock induced in the concrete by the hammer mass  51 . The shock of the hammer blow is reflected by the anvil  42 , which helps crack and then break up the concrete. 
   In another embodiment the cylinder  53  is a duplex cylinder having N 2  compressed by the hydraulic lifting of the piston  84  in the hydraulic cylinder  53 . The compressed N 2  valve  95  and flex hose or piping  97  to reservoir  96  where it stays in compression until needed to accelerate the piston downward to increase the impact of the hammer mass  51  over a gravity drop hammer. When it is desired to increase the impact of the hammer mass  51  valve  95  is opened and the compressed N 2  passes from the reservoir  96  through flex hose or piping  97  to the hydraulic cylinder  53  and applies force to the piston to accelerate the hammer mass and increase the impact on the concrete. The hydraulic cylinder  53  thereby stores hydraulic force in the form of compressed gas on the upstroke of the hammer mass  51  to be used later in the downstroke. N 2  is the preferred gas in a duplex hydraulic cylinder because it does not have a diesel effect acting with hydraulic oil leakage. 
   The hammer assembly  50  has a pivotable connection to the mounting plates  104  by a mounting hinge pin  94  through apertures in the mounting hinge and apertures on the guide plate mounting  102 . The pivoting of the guide plate  82  allows the hammer mass  51  to be tilted downward for servicing and for transportation. Further, the pivoting is useful for angling the hammer head  58  to be perpendicular to the concrete surface to be broken up. The top portion of guide plate mounting  82  has anti-bind rods  120  for adjusting the angle of the hinge mounting plate  92  and therefore the hammer mass  51 . A spring  122  between the anti-bind rod  120  and the mounting hinge plate  92  allows the hammer head  58  and teeth  59  to be angled slightly so as to be easier to lift off the concrete rather then be pinched by or angled into the concrete and thereby be caught and harder to lift out of the concrete. The hydraulic cylinder  53  then expends less energy lifting the hammer mass  51  after it impacts the concrete. The pivot angle for lift out is important when the hammer is on a moving vehicle since the concrete will be changing position under the hammer when the hammer teeth  59  are imbedded in the concrete. 
   The mounting hinge bracket  104  is attached by bolting to the hinge mounting plate  92  and to a mounting support  105  which is attached to a frame of a vehicle by brackets  106  to mount the hammer assembly for use on a pavement removal machine. 
   A plurality of hammer assemblies  50  attached to the mounting support  105  each hitting at different times can efficiently break a road surface or other wide concrete product apart. In a preferred pattern of hammering there are five hammers, first one of the outside hammers  50  hits the pavement then the other outside hammer, then an inside hammer then the other inside hammer and then the center hammer. In this manner first the outside edges of the road are broken then a middle portion and then the center. 
   For the hammer assembly  50  shown in  FIG. 4  the hammer mass  51 , guide plates  80 ,  82 , and hydraulic cylinder  53  are all positioned to minimize the effects of friction on hammer mass  51  velocity. This is assured by the down stroke of the cylinder piston  84  to be directly in line with the hammer mass  51  center of gravity and guide plates  80 , 82  that act parallel and in symmetry with the driven motion. The hammer assembly  50  is mounted on a hinge assembly  101  arrangement that allows the hammer assembly  50  to rotate to a horizontal position for servicing. 
   The pivoting hinge assembly  101  axis may include shock isolation that is not attenuated by the fracturing process. The linkage pivot may employ rubber rings between bearing races. 
   In  FIGS. 5-7  an alternative embodiment pavement removal machine  100  is presented where instead of four tracks  32 , one at each corner of the frame, two tracks  132  are used. The tracks  132  are longer and centrally placed on the frame. As shown in  FIG. 7  the pavement removal machine  100  is used to tear up pavement  20  and recycle the concrete  22  and steel rods or mesh  25  as in pavement removal machine  10 . In pavement removal machine  100  machine leveling pistons  136  level the machine with respect to the pavement  20 , and elevation and pitch control pistons  138  control the elevation and pitch of the anvil  42  and the wedge  40 . 
   One problem encountered in removal pavement  20  are dips in the road which would impede the leading edge  44  and wedge  40  from lifting the pavement  20 . The pavement removal machine  100  configured with just the hammer  50  for decracking the pavement  20  across the road in spaced part lines  27  will help resolve the problem of lifting the pavement  20  onto the anvil  42 . Similarly if the pavement  20  has expansion separations  29  which are too far apart for the leading edge  44  and the wedge  40  to handle due to angles of lifting the pavement  20  then the pavement  20  can be decracked at shorter intervals  27 . The pavement removal machine  100  has machine leveling pistons  136  to control the hammer  50  so that it is perpendicular to the pavement  20 . The hammer  50  decracks the pavement  20  at designated places  27  prior to the pavement removal machines as shown in  FIGS. 1 and 7  lifting up the pavement  20  and processing it for recycling. 
   Actuator bars  201 ,  202 ,  203  and  204  are used in conjunction with sensors which control the movement of the hammer by computer and valving. 
   Hoisting eye  225  is used in conjunction with a crane for lifting the hammer mass  51  out of the power hammer assembly  50  or placing the hammer mass  51  in the power hammer assembly  50 . Since the hammer mass can be on the order of 2200-5500 kilograms (4850-12,125 pounds) a crane is needed to assemble the power hammer assembly  50  and to replace worn or broken hammers. 
   Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.