Abstract:
A jaw set utilizes blade inserts having serrated surfaces which draw in to capture and cut material prior to the material becoming trapped in the apex of the blade arrangement, thereby maximizing efficiency of the cutting operation. The subject invention is also directed to an individual blade insert having grooves that are longitudinally offset from bolt holes used to retain the blade insert within a jaw set.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a jaw set used in demolition and recycling equipment. More particularly, the present invention relates to a jaw set having serrated blade inserts to provide for efficient cutting of wire cable, small diameter pipe, and the like. 
     2. Description of Related Art 
     While the present invention relates to demolition and recycling equipment, this equipment is also referred to as construction equipment and scrap handling/processing equipment. The description of demolition equipment, recycling equipment, scrap handling equipment, or construction equipment is not intended to be restrictive to the equipment being referenced. 
     In the dismantling of an industrial site, wire cable and small diameter pipes are often encountered.  FIG. 1  is prior art and illustrates a shear attachment  10  having a jaw set  20  made up of a first jaw  25  and a second jaw  30  which rotates relative to the first jaw  25  about a rotational axis RA. A first jaw blade  40  extends from a front end  45  of the first jaw  25  to a back end  50  of the first jaw  25  proximal to the rotational axis RA. The first jaw blade  40  has a front section  55  and a rear section  60  forming an obtuse angle A relative to the front section  55  defining an apex  65  therebetween. 
     A second jaw blade  70  extends from a front end  75  of the second jaw  30  to a back end  80  of the second jaw  30  proximate to the rotational axis RA. 
     The first jaw blade  40  and the second jaw blade  70  have mounted therein blade inserts having smooth surfaces as illustrated in  FIG. 1 . 
     While this configuration is capable of cutting small diameter pipe P and, additionally, wire cable, as illustrated for pipe in  FIG. 2 , the manner by which it does so is not efficient and results in premature wear. In particular, as the first jaw  25  and the second jaw  30  come together, the pipe P is moved along the first jaw blade  40  and the second jaw blade  70  until the pipe P contacts the apex  65 , at which time the cutting proceeds. This occurs because, as the first jaw  25  and the second jaw  30  come together, there exists between the front section  55  of the first jaw  25  and the section  70  of the second jaw  30  an acute angle B. More particularly, the acute angle B is measured from the cutting surface  42  of the first jaw blade  40  and the cutting surface  72  of the second jaw blade  70 . While this may be an effective means of cutting the pipe because the small diameter pipe P always migrates to the apex  65 , since the first jaw blade  40  and the second jaw blade  70 , in the region of the apex, are the only regions used to cut the pipe then, over time, this small segment adjacent to the apex  65  of the first jaw blade  40  and the opposing portion of the second jaw blade  70  experience excessive wear relative the remaining portions of the first jaw blade  40  and the second jaw blade  70 . 
     A design is needed to provide for more efficient cutting of small diameter pipes and wire cable by utilizing a greater portion of the first jaw blade and the second jaw blade. 
     SUMMARY OF THE INVENTION 
     The subject invention is directed to a jaw set for demolition equipment, wherein the jaw set is made up of a first jaw and a second jaw and, wherein at least one jaw rotates relative to the other jaw about a rotational axis. The jaw set comprises a first jaw blade extending from a front end of the first jaw to a back end of the first jaw proximate to the rotational axis, wherein the first jaw blade has a front section and a rear section forming an obtuse angle relative to the front section defining an apex therebetween. At least one blade insert is secured to each of the front section and the rear section of the first blade, wherein each blade insert has a longitudinal axis extending along the length of each insert. At least one blade insert of the front section has a cutting surface with grooves spaced along the longitudinal axis to provide a serrated cutting surface. A second jaw blade extends from a front end of the second jaw to a back end of the second jaw proximate to the rotational axis. At least one blade insert is secured to a section of the second blade, wherein each blade insert has a longitudinal axis extending along the length of each insert. At least one blade insert of the section has a cutting surface with grooves spaced along the longitudinal axis to provide a serrated cutting surface. In a closed position, the cutting surface of the blade insert of the front section of the first jaw forms an acute angle with the cutting surface of the blade insert of the section of the second jaw blade. 
     In a second embodiment of the subject invention, a blade insert for use with jaws for demolition equipment has a generally rectangular body with a longitudinal axis extending thereon and a width extending thereacross. Each blade is comprised of a top side having a cutting surface. The cutting surface has grooves extending thereacross with planar surfaces therebetween. Bolt holes extend through the width of the blade and are positioned along the longitudinal axis at a location spaced from that of the grooves to provide maximum strength to the blade. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is prior art of a shear attachment used with demolition equipment illustrating a first jaw blade and a second jaw blade having blade inserts with smooth edges with the jaws in the open position; 
         FIG. 2  is the shear attachment illustrated in  FIG. 1  with the jaws moving towards the closed position. 
         FIG. 3  shows a jaw set in accordance with the subject invention cutting a small diameter of pipe; 
         FIG. 4  shows the jaw set of subject invention cutting wire cable; 
         FIG. 5  is a side view of a jaw set in accordance with the subject invention; 
         FIG. 6A  is a side view of a blade insert in accordance with the subject invention; 
         FIG. 6B  is a top view of the blade insert of  FIG. 6A ; 
         FIG. 6C  is a perspective view of the blade insert illustrated in  FIG. 6A ; 
         FIG. 7  is an end view of a jaw set in the open position; 
         FIG. 8  is an end view of a jaw set approaching the closed position; 
         FIG. 9  is a perspective view of the subject invention with the blade inserts illustrated in an exploded position; and 
         FIG. 10  is a perspective view from another direction of the jaw set illustrated in  FIG. 9 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The inventors have discovered that by changing the configuration of the blade inserts in the jaw set, it is possible to cause the cutting of a small diameter pipe or a wire cable to occur at different locations along the first jaw blade and the second jaw blade and to minimize or prevent the cutting of such items at the apex location. By utilizing different areas of the first jaw blade and the second jaw blade for cutting, not only is the blade wear at the apex minimized or eliminated, but, furthermore, by distributing the cutting along different parts of the jaw blades, the life of the blade inserts may be significantly extended while, at the same time, maintaining a high quality cut. The modification of the subject invention relative to the prior art is the substitution of one or more blade inserts within the jaw blades to provide serrated blade inserts as opposed to smooth blade inserts. In particular, the inventors have discovered that by providing serrated blade inserts within the first jaw blade and the second jaw blade, the small diameter pipe or the wire cable is essentially grabbed and not permitted to slide along the jaw blade to the apex. Additionally, such a configuration may be more effective in cutting larger structural steel because the serrated blade inserts cause the steel to yield before the part is cut, thereby reducing the force needed to sever the part. 
     Directing attention to  FIG. 3 , blade inserts with such serrations are illustrated in the first jaw blade  40  and second jaw blade  70 . In  FIG. 3 , the small diameter pipe P is retained by the serrations and restrained from sliding within the jaw set  20  back to the apex  65 . In a similar manner, directing attention to  FIG. 4 , wire cable W is shown between the first jaw blade  40  and the second jaw blade  70  and, once again, is retained and not permitted to slide back to the apex. It can be appreciated that, by utilizing this design, either the small diameter pipe P or the wire cable W may be retained within the jaw set  20  where the initial contact between the pipe P or the wire cable W with the first jaw blade  40  and the second jaw blade  70  initially occurred. This design provides not only a cleaner cut for small diameter pipes but, furthermore, with respect to wire cable W, the relative motion of the first jaw blade  40  and the second jaw blade  70  tends to roll the wire cable W such that, not only is the wire cable W cut, but, during the process, the wire cable W is also unwound, thereby further reducing the cutting forces needed by the jaw set  20  to effectively cut the wire cable W. 
     Directing attention to  FIG. 5 , the jaw set  20  is made up of a first jaw  25  and a second jaw  30 , wherein at least one jaw rotates relative to the other jaw about a rotational axis RA. 
     The jaw set  20  is made up of a first jaw blade  40  extending from a front end  45  of the first jaw  25  to a back end  50  proximate to the rotational axis RA. The first jaw blade  40  has a front section  55  and a rear section  60  forming an obtuse angle A relative to the front section  55  defining an apex  65  therebetween. 
     At least one blade insert  100  is secured to the front section  55  of the first jaw blade  40  and at least one blade insert  105  is secured to the rear section  60  of the first jaw blade  40 . Each blade insert has a longitudinal axis L extending along the length of that insert. 
     Directing attention to  FIGS. 6A-6C , at least one blade insert  100  of the front section  55  has a cutting surface  110  with grooves  115   a ,  115   b ,  115   c ,  115   d  spaced along the longitudinal axis L to provide a serrated cutting surface. 
     Returning to  FIG. 5 , a second jaw blade  70  extends from a front end  75  of the second jaw  30  to a back end  80  of the second jaw  30  proximate to the rotational axis RA. At least one blade insert  120  is secured to a section  85  of the second jaw blade  70 , wherein the blade insert  120  has a longitudinal axis L extending along the length of the insert  120 . From inspection of  FIG. 5 , it should be pointed out that the second jaw blade  70  has associated with it a second blade insert  125  similar to blade insert  120 . 
     The blade inserts  120 ,  125  have similar features as those associated with blade insert  100  and, as a result, the blade insert  100 , previously discussed with respect to  FIGS. 6A-6C , also describes the blade inserts  120 ,  125  associated with the second jaw blade  70 . 
     Directing attention again to  FIGS. 6A-6C , planar segments  130   a ,  130   b ,  130   c  are interspersed between the grooves  115   a ,  115   b ,  115   c ,  115   d.    
     Of particular importance with respect to the subject invention,  FIG. 6A  illustrates the blade insert  100  having bolt holes  135   a ,  135   b ,  135   c  extending therethrough perpendicular to and along the length of the longitudinal axis L and parallel to the planar segments  130   a ,  130   b ,  130   c . The bolt holes  135   a ,  135   b ,  135   c  are longitudinally spaced from each groove  115   a ,  115   b ,  115   c ,  115   d  to provide maximum blade strength. In contrast, if a bolt hole  135   a  is aligned with, for example, a groove  115   a , then the cross-sectional area of the material of the blade insert  100  has diminished structural integrity. 
     As illustrated in  FIGS. 6B and 6C , the grooves  115   a ,  115   b ,  115   c ,  115   d  are oriented perpendicular to the longitudinal axis L. 
     As further illustrated in  FIG. 6B , blade insert  100  has a width W and the grooves  115   a ,  115   b ,  115   c ,  115   d  extend across the width W of the blade  100 . Additionally, directing attention to  FIG. 6A , the length L 1  of planar segment  130   a  is greater than or equal to the length L 2  of the adjacent groove  115   b . This relationship applies to all of the planar segments  130   a ,  130   b ,  130   c , with respect to the grooves  115   a ,  115   b ,  115   c ,  115   d . It should be noted that the end planar sections  140   a ,  140   b  may not retain this relationship. However, in the event blade insert  100  is placed adjacent to another blade insert, then, the combined length of the end planar section  140   a  and, for example, end planar section  140   b  of another insert will maintain this same relationship, wherein their combined length is greater than or equal to the length of an adjacent groove, such as groove  115   a.    
     Directing attention to  FIG. 5 , it may be preferred to provide smooth blade inserts  145   a ,  145   b  without grooves at the front end  45  of the first jaw blade  40  and at the front end  75  of the second jaw blade  70  for the purposes of allowing the work piece, such as the small diameter pipe P or the wire cable W, to move further within the jaw set  20  to increase the mechanical advantage of the cutting action. The blade insert  150  positioned between the apex  65  and the rear section  60  of the first jaw blade  40  may also have a smooth surface without grooves to urge any workpiece toward the opposite side of the apex  65 . 
     Directing attention to  FIG. 6A , in one embodiment, the groove  115   a ′, for example, has a depth of ¼ inch and a length L 2  of ½ inch. It should be noted that the geometry of the grooves is preferentially uniform within each blade insert  100  and, for that reason, the discussion of groove  115   a ′ may be applicable to the other grooves in the blade insert  100 . Additionally, from  FIG. 6A , it should be appreciated that the grooves  115   a ,  115   b ,  115   c ,  115   d  on the top side  155  of the blade insert  100  are duplicated and indicated as  115   a ′,  115   b ′,  115   c ′,  115   d ′ on the bottom side  160  of the blade insert  100 . By doing so, each blade insert  100  may be indexable, such that when the cutting edge on one side begins to wear, the blade insert  100  may be flipped to provide a fresh cutting edge. 
     As a general guideline, the groove length L 2  may be at least twice the depth of the groove depth D. 
     As illustrated again in  FIG. 6A , the grooves  115   a , for example, may be generally U-shaped and radiused at the corners of the base to minimize stress concentration factors. However, the intersection of the grooves  115   a , for example, with the planar segments  130   a , for example, may have a sharp corner to promote cutting. 
     While it was previously mentioned that the bolt holes  135   a ,  135   b ,  135   c  are intentionally positioned away from the grooves  115   a ,  115   b ,  115   c ,  115   d , it should be appreciated that the length of the planar sections  130   a , for example, may vary to permit the bolt holes  135   a ,  135   b ,  135   c  to be offset from the grooves  115   a ,  115   b ,  115   c ,  115   d.    
     The invention is also directed to a blade insert  100  for use with jaws for demolition equipment, wherein the blade insert  100 , as illustrated in  FIG. 6C , has a generally rectangular body  165  with longitudinal axis L extending thereon and a width W extending thereacross. The blade insert  100  is comprised of a top side  155  having a cutting surface  110  with grooves  115   a ,  115   b ,  115   c ,  115   d  extending thereacross and with planar surfaces  130   a ,  130   b ,  130   c  therebetween. Bolt holes  135   a ,  135   b ,  135   c  extend through the width W of the blade insert  100  and are positioned along the longitudinal axis L at a location spaced from that of the grooves  115   a ,  115   b ,  115   c ,  115   d  to provide maximum structural integrity of the blade. 
       FIG. 7  and  FIG. 8  are schematic cutaway views along lines  7 - 7  in  FIG. 1  and lines  8 - 8  in  FIG. 2 , respectively.  FIG. 7  illustrates the small diameter pipe P in position with the first jaw  25  and the second jaw  30  opened.  FIG. 8 , on the other hand, illustrates the small diameter pipe P after contact is made by the blade insert  100  and the blade insert  120  to begin the cutting operation. It should be appreciated that there is very little lateral distance between the blade insert  100  and the blade insert  120  to maximize the shear imparted to the workpiece, such as pipe P. 
     Directing attention to  FIGS. 9 and 10 , it should be noted that each blade insert  100 , for example, fits within a recessed area  170  of the first jaw  25  and is secured therein with bolts (not shown) extending through the bolt holes  135   a ,  135   b ,  135   c  and secured to the first jaw  25 . Each of the blade inserts, such as blade inserts  120 ,  125 , is secured in a similar fashion. It should also be noted that the jaw  25  and the jaw  30  are commercially available and, as a result, all that is required to upgrade the jaw set  20  to significantly improve performance in cutting small diameter pipe and wire cable is to replace blade inserts with the serrated blade inserts disclosed herein. 
     It should also be apparent from inspection of  FIG. 9  and  FIG. 10  that the blade insert  100  associated with the first jaw  25  is within a recessed area and that the blade inserts  120  and  125  associated with the second jaw  30  are located in another recessed area  175  in opposing relationship with the recessed area  170  of the first jaw  25 . 
     It has been found that the serrated blade inserts of the subject invention cut 80-90% longer than the traditional smooth blades before requiring blade rotation to a new edge. This benefit does not factor in the further extended blade life that can be achieved by sharpening and shimming. 
     An added benefit of the serrated blade inserts occurs during the cutting operation, wherein the blade inserts progressively saw through the wire cable in the same fashion as a hack saw blade cuts, rather than trying to sever the cable, like chopping at something with a dull axe. While the sharp shear blade edge of the cutting insert does cut the cable, the cutting action is further implemented because the serrated blade insert utilizes a tearing or shredding action rather than complete shearing or snipping. Additionally, serrated blades weaken the structural integrity of wire cable by unraveling it, while simultaneously shredding the strands, which enable the blades to cut the cable with far less effort, thus minimizing overall wear and tear to the blades and all of the other shear components. 
     When cutting small diameter pipe, the smooth, traditional blade inserts gather and bunch the material, forcing the jaw to cut a mass of material all at once in the region of the apex. In contrast, utilizing the serrated blade inserts, smaller diameter material is trapped at various notches along each of the blades, sequentially spreading out the strands of the cable, thus using a fraction of the energy to cut the same material volume, resulting in longer blade life, less stress on the blade bolts, and overall lower maintenance.