Abstract:
A known stone cutter having an upper jaw powered for a guillotine type cut has a transverse bar in the upper jaw. A series of cube shaped cutter units are mounted side by side along the transverse bar. An isostatic manifold connects all the cutter units for contouring the cutter jaws to the irregular rock surface. At cut time each cutter unit is hydraulically isolated via a shuttle valve from the isostatic manifold so as not to transmit huge cutting pressures to the isostatic manifold and unused cutter units in that cut.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a non-provisional application claiming the benefits of provisional application No. 60/139,361 filed Jun. 14, 1999. 
    
    
     FIELD OF INVENTION 
     The present invention relates to a stone cutter having a pair of hydraulically activated jaws, wherein a cutting element block of a jaw(s) is made of a plurality of modular cylinder blocks. Each cylinder block houses a hydraulically activated cutting element. After wear each individual cylinder block can be replaced, thus saving replacement of the entire cutting element block. 
     BACKGROUND OF THE INVENTION 
     Stonecutters for cutting rough surfaced stone bodies are well known in the art. U.S. Pat. No. 3,809,049 (1974) to Fletcher et al. discloses a guillotine type stone cutter having an upper jaw which has a plurality of individual cutter units welded to a transverse frame base. The frame base can be detached from the upper jaw for maintenance. However, the individual cutter units cannot be replaced without a welding operation. Fletcher does address the problem of cutting a rock having an uneven top surface by claiming his cutter units can extend their cutting elements three to five inches in order to conform to a rock&#39;s surface. In operation a common manifold pressures all the pistons in the cutting elements to extremely heavy loads in the 8000 to 10,000 pound range. This hydraulic pressure forces each piston against a surface of the rock at varying heights. Then the manifold input is shut thereby equalizing all the pressure in the manifold, in the supply pipes to each cylindrical cutter element, and in the cylinders of each cutter element. Thus, expensive supply pipes are needed to withstand up to 10,000 pounds of pressure. Then the cut is made by powering the upper jaw to move downward. 
     Problems. with Fletcher&#39;s design include a high cost in labor to replace a worn cutter unit, a high cost in production to cover high pressure hydraulic supply pipes to each cutter unit and an apparent design flaw which would not let a cutting element to fully extend under pressure. It appears that the end cap would explode off at high pressure. Thus, only rocks that were large enough to contact all the cutting elements could be cut. 
     Other variably extending cutter element systems use an in-line cylinder block design. The cylinder head affixes to the upper jaw. Each cutter element is a piston extending downward in the cylinder head. The common manifold is piped to the individual cylinders. One problem with this old design is the necessity to replace the entire cylinder block at a cost of over $10,000 when a few central cylinders wear out due to the extra wear and tear on the central cutting elements. 
     The present invention solves several problems in the art including offering a modular cylinder block. Each cutter unit especially the central ones can be disconnected by bolts from the upper jaw and replaced for far less than $10,000. Also each cutter unit is individually valved to disconnect from the manifold once an isostatic state is reached among the cylinders of the cutter elements. Thus, only plastic 250 pound piping is needed to each cutter unit. This saves considerable costs in manufacturing since dozens of cutter units exist on a single machine. Another benefit of the modular bolted on cutter unit design is the ease with which variable width cutting assemblies can be made. Only the transverse mounting bar needs to be custom cut to the width of the stone cutting machine or a subset thereof if desired. Then the proper number of cutter units are bolted on to the transverse bar, and assembly is complete. This is a far less expensive technique than casting a different width cylinder block for each varying width cutter. 
     SUMMARY OF THE INVENTION 
     The main aspect of the present invention is to provide a modular set of bolt on cutter units to a transverse mounting bar for a jaw of a guillotine type stone cutter. 
     Another aspect of the present invention is to provide a shut off valve from the manifold for each cutter unit. 
     Other. aspects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 (prior art) is a front perspective view of a guillotine type stone cutter. 
     FIG.  2 . is a front plan view of the preferred embodiment of the stone cutter having modular cutter units. 
     FIG.  3 . is a front plan close up view of the modular cutter units of FIG.  2 . 
     FIG.  4 . is a top perspective view of the modular cutter units. 
     FIG.  5 . is an exploded view of the modular cutter units. 
     FIG.  6 . is a top plan view of a modular cutter unit. 
     FIG.  7 . is a sectional view of the modular cutter unit taken along line  7 , 8  of FIG. 6 with the cutting element extended. 
     FIG.  8 . is the same view as FIG. 7 with the cutting element withdrawn. 
     FIG.  9 . is a sectional view of the modular cutter unit taken along line  9 — 9  of FIG.  6 . 
     FIG.  10 . is a front plan view of a wide body embodiment of the present invention. 
     FIG.  11 . is an exploded view of the preferred embodiment master cylinder assembly. 
    
    
     Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to FIG. 1 a guillotine type machine  1  is generally called a stone cutter. Spaced vertical sides  2 , 4  support a hydraulically controlled ram means well known in the art. Located between the vertical sides  2 , 4  are upper and lower transverse beam members  6 , 8 . One or both of the transverse beam members  6 , 8  move under hydraulic ramming power to cut a rock  9  stationed between them. Usually both the upper and lower transverse beam members  6 , 8  have a cylinder block  10 , 12  respectively, wherein each cylinder block  10 , 12  supports piston—like upper cutting elements  13  and lower cutting elements  130 . A hydraulic. manifold  14  is piped to each of the upper cutting elements  13  so as to allow each cutting element to contour to the peaks and valleys on top of the rock  9  and create an isostatic pressure among the manifold and the individual cylinder block cylinders (not shown) inside the cylinder block  10 . Once the isostatic pressure is obtained and the cutting elements  13  are contiguous with the top surface of the rock  9 , the hydraulic piston  15  powers the upper transverse bar  6  via piston  16 , thereby forcing the cutting elements  13 ,  130  through the rock. If a central cylinder block cylinder  131  becomes worn, then hydraulic fluid having pressures up to 10,000 pounds will leak out. Such a leak will both discolor the rock and render the cutting element  131  useless. Conveyor rolls Cl are arranged between the vertical sides  2 , 4  for receiving a rock  9  such as a block of granite and moving the rock a longitudinal path of travel into the desired position for a cut. 
     Referring next to FIG. 2 the preferred embodiment stone cutter  20  is shown to have spaced vertical sides  21 , 22  which support hydraulic rams  23 , 24 . The hydraulic rams  23 , 24  force the upper transverse bar assembly  27  via pistons  25 ,  26  with tons of force. A lower transverse bar  28  is stationary. Preferably all the cutter units  29  are identical. Each has a master cylinder  30 , a piston rod  31 , a cutter jaw  32  which has a replaceable tooth  33 . The master cylinder is bolted to the upper transverse bar assembly  27  at mounting bar  270 . 
     Hydraulic assemblies  34 , 340  are piped to each cylinder block  29  to create an upper isostatic pressure for the upper row of cutter units denoted U and a lower isostatic pressure for the lower row of cutter units denoted L. In operation the upper transverse bar assembly  27  is slowly moved down to engage the upper row of cutter units U as well as the lower row of cutter units L with the upper and lower surfaces of the rock  9  respectively. Thus, each set of cutter units U,L conform their cutting jaws  32  with the contours of the rock  9  via isostatic pressure. The nominal range of deviation between the minimum and maximum extension of each piston rod  31  is 1.75 inches. It doesn&#39;t matter if some cutter units  29  are not in contact with a rock surface because each master cylinder  30  is isolated from the hydraulic assemblies  34 ,  340  before the cut is made. Thus, only 250 pounds of force or less is contained in the control lines  310 ,  311  which do not take part in the cut such as master cylinder  393 . A cover  399  shields the hydraulic connections to the master cylinders. 
     Referring next to FIG.3 the hydraulic input line  310  (running under 250 pounds) powers the master cylinders  30  until isostatic pressure is reached among all the master cylinders  30 . Then hydraulic control line  311  is charged thereby isolating via shut off shuttle valve  70  shown in FIGS.  7 , 8  each master cylinder. 
     Referring next to FIG. 4 the master cylinder  30  may be made of segments  317 , 318 , wherein bolts  319  secure each master cylinder  30  to the transverse mounting bar  270 . The piping  311 , 312 , 313 , 315  can be plastic with a 250 pound rating (rather than a tonnage rating) because the isostatic pressure for positioning each cutter tooth  32  is isolated from the tonnage pressure created by the cut in the master cylinder/cutter jaws in contact with the rock. 
     Referring next to FIG. 5 the piston  31  has a groove  50  to keep it aligned. A key  51  goes in slot  57  and into the groove  50 . Each neighboring master cylinder segment acts as a lock to keep the key  51  in place (see FIG. 4 wherein segment  499  locks the key of segment.  498  in place with segment  499 &#39;s side surface  55 ). 
     Holes  58  receive bolts  319 . A bolt  55  secures a piston base  52  to the piston rod  31 . Piston base  52  has a groove  53  which secures the seal  54  thereto. 
     Segment  317  has a hole  555  which aligns hole  556  in segment  318 . Hole  555  has a groove  557  which secures the dirt seal  56 . 
     Referring next to FIG. 7 the shuttle valve  70  comprises an inlet port  313  which isostatically pressurizes the cylinder chamber  700 . When the cut is to be made the shuttle valve  70  isolates each master cylinder  30  by pressurizing control port  315 , thereby forcing valve pin  75  across inlet port  313  as shown in FIG.  8 . The hydraulic pressure to inlet port  313  is temporarily cut off. 
     Referring next to FIG. 9 members  31 ,  32  are machined from one piece of metal. 
     Referring next to FIG. 10 a wide body stone cutter  1000  has a jaw width d 1 . The upper U and Lower L cutter unit assemblies  1001 , 1002  respectively are cost effectively manufactured by bolting the necessary number of cylinder blocks  30  onto their custom length d 1  transverse bars (not shown but analogous to  270 , 28 ). 
     Referring next to FIG. 11 the preferred embodiment structure for stabilizing the piston rod  31  of FIG. 5 is shown, wherein piston rod  310  now has three vertical grooves  312 , 313 , 314 . Three alignment balls  311  ride in grooves  312 , 313 , 314 , and are held in place by their respective receiving grooves  3172 , 3174 , 3173 , in the collar  3171  which fits into a recess  3175  of the master cylinder segment  3170 . 
     Although the present invention has been described with reference to preferred embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.