Abstract:
A blade stabilizer device for a heavy-duty material handling demolition tool for shearing and crushing scrap material which includes a lower jaw connected to the boom structure of a hydraulic system of an excavator has an upper jaw pivotally connected to and closable upon the lower jaw at a pivot point. The blade stabilizing device consists of a wear guide pad supported by the lower jaw adjacent the pivot point slidably engaging the movable upper jaw to keep the upper jaw in close engagement with the lower jaw. The wear guide pad is mounted behind the pivot point. A second wear guide pad may be mounted in front of the pivot point on the opposite side of the upper jaw to cross-brace the upper jaw.

Description:
BACKGROUND OF THE INVENTION 
     A fuller understanding of the operation of the demolition apparatus of the present invention may be achieved by studying U.S. Pat. Nos. 4,519,135 and 6,061,911, hereby incorporated by reference. This invention relates to a heavy duty demolition apparatus, especially adapted to be mounted on a rigid boom of a mobile vehicle and particularly adapted to be mounted on the dipper stick of an excavator, with a blade stabilizing device or puck to keep the upper jaw of the apparatus from moving laterally relative to the lower jaw and breaking during the shearing operation on a workpiece. 
     Heavy duty shears of the type that are powered by hydraulic cylinders are proving more and more useful in handling scrap and especially metal scrap of all sorts. Such scrap comes in many different forms, and may be in the form of pipes made of steel or soft iron or cast iron, ranging in sizes from 2 inches or smaller, and up to 8 or 10 inches in diameter or larger; structural beams such as I-beams, channels, angle beams in a large range of sizes, up to 8 or 10 inches across and larger; rods and heavy cables having diameters of 2 to 3 inches and larger, metal sheets and plates and formed metal of all sorts including wheels and automobile and truck frames, and a myriad of long and short pieces of stock and metal pieces that are cast, rolled, stamped or otherwise formed, both singly and in various types of assembly. 
     The prior art has included numerous shears such as that illustrated in U.S. Pat. Nos. 4,198,747; 4,188,721; 4,897,921; 4,543,719; 4,558,515 and 4,104,792. Typically, these heavy duty shears mount on the dipper stick of an excavator so that the shears may be controlled fairly well in handling various types of scrap and cutting the scrap into smaller pieces and lengths. 
     Typically, these shears have a fixed lower jaw and a movable upper jaw that pivots on the lower jaw, with shear blades of hardened steel on both the upper jaw and the lower jaw. The workpiece is sheared by closing the upper jaw against the lower jaw under hydraulic pressure, with the shear blades cutting the workpiece. 
     Unfortunately, great lateral as well as vertical pressure develops against the movable upper jaw as it contacts and proceeds to cut the workpiece. This lateral pressure can cause the upper jaw to crack or otherwise experience structural failure. This lateral pressure exists from the moment the upper jaw contacts the workpiece until the workpiece is cut and the upper jaw meets the lower jaw and becomes supported by the lower jaw in a slot in the lower jaw. This lateral force develops analogously to when a person tries to cut too heavy an object with a pair of scissors. The scissors&#39; blades are forced laterally apart and may break. 
     There is a need for a heavy duty demolition shear with a blade stabilizing device that prevents lateral movement of the upper jaw relative to the lower jaw and which supports the upper jaw against this lateral pressure. 
     In rebuilding highways for motor vehicle travel, and in the demolition of structures which are largely made of or incorporate reinforced concrete as structural members, the disposal of large pieces of concrete paving or reinforced concrete structure becomes a significant problem. Many governmental regulations and practical considerations relating to the operation of landfills prohibit the disposal of concrete slabs and large reinforced concrete structures by simply burying them in the landfills. Accordingly, it becomes necessary to dispose of such concrete material in other ways. 
     Crushing of the concrete is one alternative so that the concrete slabs and structures may be reduced to smaller particle sizes which accommodates the reuse of such concrete as fill and as aggregate base for roadways and the like. 
     It has been possible in the past to reduce concrete into particles and chunks by use of heavy duty shears, but such shears which are primarily designed for shearing steel and other metallic and wood structures have sharpened blades and are rather expensive for the purpose of reducing concrete slabs and structures which is thought to be accomplished in other ways. Such crushers are shown in U.S. Pat. Nos. 5,478,019; 4,512,524; 5,183,216; 5,044,569; and 4,951,886. 
     Furthermore, crushing concrete may result in the development of lateral pressure against the movable upper jaw of a demolition shear in the same way that shearing metal does. 
     There is a need for a demolition apparatus with a blade stabilizing device that prevents lateral movement of the upper jaw relative to the lower jaw and which supports the upper jaw against this lateral pressure. 
     SUMMARY OF THE INVENTION 
     A blade stabilizer device for a heavy-duty material handling demolition tool for shearing and crushing scrap material which includes a lower jaw connected to the boom structure of a hydraulic system of an excavator and has an upper jaw pivotally connected and closeable upon the lower jaw beginning at the pivot point. The blade stabilizing device consists of a wear guide supported by the lower jaw adjacent the pivot point slidably engaging the upper movable jaw to keep the upper jaw in close engagement with the lower jaw. The wear guide is mounted behind the pivot point. A second wear guide may be mounted in front of the pivot point on the opposite side of the upper jaw to cross-brace the upper jaw. 
     An object and advantage of the invention is to provide an improved heavy-duty material handling demolition tool for shearing and crushing scrap material with a blade stabilizing device which prevents the upper jaw from moving laterally relative to the lower jaw, thus improving the cutting ability of the tool for heavy scrap material. 
     Another object and advantage of the present invention is to provide a blade stabilizing device for a heavy-duty demolition tool which reduces lateral stress on the upper jaw caused due to shearing the workpiece. 
     Another object and advantage of the present invention is that the blade stabilizing device is removable and replaceable when worn due to friction with the upper jaw. 
     Another object and advantage of the present invention is that the clearance between the blade stabilizing device and the upper jaw is adjustable to compensate for wear. 
     Another object and advantage of the present invention is that the blade stabilizing device contacts a wear surface on the upper jaw and the wear surface is dimensioned such that the blade stabilizing device does not contact the wear surface once the upper jaw is securely received in the lower jaw. 
     Another object and advantage of the present invention is that the blade stabilizing device may comprise a first stabilizer or puck mounted to the rear of the pivot point and a second stabilizer or puck mounted in front of the pivot point, thereby providing cross-bracing to the upper jaw. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a right-side perspective view of the heavy-duty demolition apparatus of the present invention. 
         FIG. 2  is a cross-section of the heavy duty demolition apparatus of the present invention at approximately the lines  2  of  FIG. 1 . 
         FIG. 3  is a right-side elevational view of the heavy-duty demolition apparatus of the present invention with some internal structure shown in phantom. 
         FIG. 3A  is a left side elevational view of the apparatus. 
         FIG. 4  is the same as  FIG. 3 , showing the upper jaw partially closed. 
         FIG. 5  is the same as  FIG. 3 , showing the upper jaw fully closed. 
         FIG. 6  is a left-side perspective view of the heavy duty demolition apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The heavy-duty demolition apparatus of the present invention is generally referred to in the Figures as reference numeral  10 . 
     Referring to  FIGS. 1 through 6 , the heavy-duty demolition apparatus  10  comprises a lower jaw  12 , an upper jaw  14 , pivot means  16  interconnecting the lower jaw  12  and upper jaw  14 , and means  18  for attachment to the excavator (not shown). The means  18  may further include a rotator unit  20  allowing rotation of the demolition unit  10  about a longitudinal axis. The apparatus  10  also includes means  30  for attachment to the hydraulic system of an excavator (not shown) for closing and opening the upper jaw relative to the lower jaw. More specifically, the means  30  includes a cylinder  30   a  having a reciprocating piston  30   b  within the cylinder  30   a . The cylinder  30   a  is connected to the hydraulic system of the excavator (not shown). The piston  30   b  connects to the upper jaw  14  at a knuckle  32 . 
     The upper jaw  14  has a first side  22 , and a second side  24 . The lower jaw  12  has a first mounting plate  26  adjacent the first side  22 , and a second mounting plate  28  adjacent the second side  24 . The first mounting plate  26  and second mounting plate  28  receive the pivot means  16  between them. 
     The upper jaw  14  has upper shear blades  34  and the lower jaw  12  has lower shear blades  36  extending along each other for shearing a workpiece when the upper shear blades  34  are closed upon the lower shear blades  36 . Preferably, the shear blades  34 ,  36  are replaceable. 
     A blade stabilizing device  38  for the apparatus  10  engages the upper jaw  14  to prevent the upper jaw  14  from moving laterally with respect to the lower jaw  12  while shearing the workpiece. 
     Preferably, the blade stabilizing device  38  further comprises a first blade stabilizer  40  attached to the first mounting plate  26  and slidably engaging the upper jaw  14  on the first side  22  of the upper jaw  14 . Optionally, a second blade stabilizer  42  may be attached to the second mounting plate  28  and slidably engaging the upper jaw  14  on the second side  24  of the upper jaw  14 . 
     Preferably, the apparatus  10  further comprises a first arcuate wear surface  44  on the first side  22  and contacting the first blade stabilizer  40  and a second arcuate wear surface  46  on the second side  24  and contacting the second blade stabilizer  42 . The second arcuate wear surface  46  may be on a hub or reinforced section of the upper jaw  14 . The wear surfaces  44 ,  46  may preferentially be constructed of a different material from the upper jaw  14  in order to better resist sliding friction cause by the first blade stabilizer  40  and second blade stabilizer  42 . 
     Preferably, the apparatus  10  further comprises a guide blade  48  on the lower jaw  12  lying along the lower shear blade  36  and in spaced relation therewith, the outer end  50  of the guide blade and outer end  52  of the shear blade being adjacent each other, and rigid means  54  securing the outer ends  50 ,  52  together. The rigid means  54  is preferably a tie plate  56 . 
     An open slot  58  preferably exists between the lower shear blade  36  and the adjacent guide blade  48  to receive the upper shear blade  34  therein, the open slot  58  having a width wider than the thickness of the upper shear blade  34  to maintain open space between the upper shear blade  34  and the guide blade  48  when the upper shear blade  34  is in the open slot  58 . Preferably, the first arcuate wear surface  44  and second arcuate wear surface  46  are of such dimensions that the first blade stabilizer or puck  40  and also perhaps the second blade stabilizer or puck  42  move off the first arcuate wear surface  44  and second arcuate wear surface  46 , respectively, when the upper shear blade  34  is received in the open slot  58 . This is because the first blade stabilizer  40  and second blade stabilizer  42  are no longer needed to brace the upper jaw  14  once the upper shear blade  34  is received in the slot  58 . 
     Preferably, the first blade stabilizer  40  and second blade stabilizer  42  are removable and replaceable when they become worn due to frictional contact with the upper jaw  14 . The first blade stabilizer  40  and second blade stabilizer  42  may also be adjustable to provide variable clearance between them and the upper jaw  14 , as for example as the blade stabilizers become worn. 
     In the preferred embodiment, the first blade stabilizer  40  is located rearwardly of the pivot means  16 .  FIGS. 1 and 2  show the details of the first blade stabilizer  40 . Most preferably, the first blade stabilizer  40  comprises a first guide  66  engaging the upper jaw  14 , means  70  for attaching the first guide  66  to the first mounting plate  26 , and a shim  76  for adjusting the clearance between the first guide  66  and the upper jaw  14 . The means  70  may most preferably be threaded bolts  72  with washers  73 , but it will be recognized that any equivalent fasteners such as screws or pins could also be used. Threaded bolts  70  preferably engage the first mounting plate  26  through recessed apertures  74 . The first blade stabilizer  40  may optionally further comprise an adjustment plate  80  between the first mounting plate  26  and the shim  72 . The first guide  66  may preferably further comprise a grease channel  82  opening onto the upper jaw  14  and a grease fitting  84  for delivering grease to the grease channel  82  for lubricating the engagement between the first guide  66  and the upper jaw  14 . The upper jaw  14  preferably has a pocket  86  in the first mounting plate  26  for receiving the first guide  66 . 
     In the preferred embodiment, the second blade stabilizer  42  is located forwardly of the pivot means  16 .  FIGS. 2 and 6  show the details of the second blade stabilizer  42 . Most preferably, the second blade stabilizer  42  comprises a second guide  90  engaging the upper jaw  14 , means  70  for attaching the second guide  90  to the second mounting plate  28 , and a shim  76  for adjusting the clearance between the second guide  90  and the upper jaw  14 . The means  70  may most preferably be threaded bolts  72  with washers  73 , but it will be recognized that any equivalent fasteners such as screws or pins could also be used. Threaded bolts  70  preferably engage the second mounting plate  28  through recessed apertures  74 . The second blade stabilizer  42  may optionally further comprise an adjustment plate  80  between the second mounting plate  28  and the shim  76 . The second guide  90  may preferably further comprise a grease channel  82  opening onto the upper jaw  14  and a grease fitting  84  for delivering grease to the grease channel  82  for lubricating the engagement between the second guide  90  and the upper jaw  14 . The upper jaw  14  preferably has a pocket  92  in the second mounting plate  28  for receiving the second guide  90 . 
     Operation of the present invention may best be seen by viewing  FIGS. 3–5 . In  FIG. 3 , the upper jaw  14  is in the open position, preparatory to shearing the workpiece. It will be seen that the guide or pad or guide pad  66  rests at one end of the first arcuate wear surface  44  and the second guide or pad or guide pad  90  rests at one end of the second arcuate wear surface  46 . In  FIG. 4 , the upper jaw has partially closed on the workpiece (not shown) and has begun to shear the workpiece. The guides  66 ,  90  are still supported by the wear surfaces  44 ,  46  respectively. In  FIG. 5 , the upper shear blade has been entirely received in the slot  58 . Consequently, the support of the guide pads  66 ,  90  is no longer required and the guide pad  66  has moved off the first arcuate wear surface  44 . Although not shown in the Figure, the second arcuate wear surface could also be dimensioned so that the guide pad  90  has moved off it at this point. 
     Before beginning operation, the operator uses a feeler gauge or a shim to measure the clearance (typically 0.003 to 0.010 inches) between the guides  66  and  90  wear surfaces  44  and  46  respectively. If the measurement is within the range of 0.003 to 0.010 inches, no adjustments are needed. If the measurement is below this range, shims  76  or  72  are either removed entirely or replaced with thinner shims to bring the arrangement within operating tolerances of 0.003 to 0.010 inches. After the pucks or guides  66  or  90  wear and the clearance is larger than 0.010 of an inch, and appropriate shim size is determined. The upper jaw  14  is then closed, the threaded bolts  70  are loosened, the shims  76  are inserted, and the bolts  70  are re-tightened. Unlike previous designs, the guides  66 ,  90  are very durable with fewer maintenance problems. The clearance between the upper jaw  14  and the guides  66 ,  90  may be adjusted as the guides  66 ,  90  wear by adding additional shims. The grease fitting allows the engagement between the guides  66 ,  90  and the upper jaw to be lubricated, reducing wear. As no fasteners traverse the mounting plates  26 ,  28  in this design, it is unlikely that the mechanism will seize, which previously required cutting out the damaged assembly and welding in a new assembly. Also, the simpler design reduces manufacturing costs. The adjustment plates  80  can be used to adjust for manufacturing variances and customized to each apparatus, but are not required for all applications. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. In case of conflict, the present specification, including definitions, will control. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.