Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D1/00—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
  • B28D1/32—Methods and apparatus specially adapted for working materials which can easily be split, e.g. mica, slate, schist
  • B28D1/322—Splitting of the working materials

Definitions

• the invention relates to a cutting apparatus for use in machines for cutting blocks of schistose materials, particularly stone materials, such as slate, which tend to cleave along cleavage planes.
• Slate is known to have the peculiar feature of being naturally layered, and exposed to cleavage along cleavage planes oriented in a cleavage direction.
• the cutting apparatus in prior art cutting machines are designed to take advantage of this peculiar feature for easier cutting of slate blocks, by applying the shear stress parallel to the cleavage planes, for the material to be divided into thinner and thinner pieces, until substantially flat slabs are obtained.
• a prior art slate block cutting machine comprises a supporting and conveying surface upon which the slate blocks to be cut are loaded, each being carried to a cutting station within the machine.
• the cutting apparatus is mounted at this cutting area, and comprises a carriage that moves on a frame, the latter overlying the cutting station on which each block is placed.
• An actuating cylinder is mounted to the carriage and vertically drives a substantially horizontal blade to a slate block cutting position.
• the blade is returned to a raised position by elastic return springs after cutting.
• the blade is slidingly mounted in a box-like support that defines a fluid-tight chamber therein, in which the blade may slide, which is connected to a compressed air source.
• the blade body has the lower cutting edge formed with a series of substantially vertical adjacent notches which have the same height and are formed at a constant pitch.
• Each notch has a blind upper end, extending to a substantially median area of the blade, whereas the opposite end is open and, as mentioned above, opens into the lower cutting edge thereof.
• this retraction provides communication between the upper ends of the notches and the fluid-tight chamber.
• the pressurized air accumulated in the fluid-tight chamber of the box-like support is ejected through these notches as a laminar jet and is forced between the two facing cutting surfaces of the slate block and, assisted by the pushing action of the blade, facilitates their separation.
• the programmed successive cutting cycles on each slate block provide slabs with substantially regular and flat cutting surfaces directed along cleavage planes, such that they substantially have a quasi-finished aspect, with reduced material waste caused by the scrap that generally results from cutting of schistose materials.
• the cutting blades are fixed to their respective supports by means of a plurality of screws transversely extending through appropriate holes formed therein and locking them to respective supports sliding in the box-like supports.
• a first drawback is that the front of compressed air obtained in prior art machines is substantially rectilinear and is only activated throughout the length of the cutting blade when the latter progressively retracts into the box- like support to a sufficient extent as to provide communication between all the upper ends of the notches and the interior of the fluid-tight chamber.
• This front is vertically directed, and is parallel to the lower cutting edge of the blade, whereby it penetrates between the cutting surfaces only in the vertical direction, throughout the width thereof.
• the penetration force of compressed air is substantially evenly distributed all along the rectilinear front of compressed air, which requires a considerable pressure to maintain the same force for separating the slate cutting surfaces all along the cutting face of the blade, which will require the use of very powerful and hence substantially expensive compressed air sources.
• the surfaces of the cutting plane have a particularly tough material therebetween, which tends to oppose the separation of the cutting surfaces of the slate block in the vertical cutting direction, it may happen that, since the direction is only vertical, the cut cannot be completed in the selected cutting plane.
• a second drawback is that the screws that extend through and lock the blades to their respective supports require the blade bodies to be formed with holes, which weaken the blade structure and overall strength.
• One object of the invention is to improve the prior art.
• Another object of the invention is to provide a cutting apparatus for use in machines for cutting blocks of schistose materials, that allows cutting along splitting planes using compressed air jets that provide the same penetration force as in prior art machines but at a lower pressure, i.e. using considerably cheaper compressed air sources.
• a further object of the invention is to provide a cutting apparatus for use in machines for cutting blocks of schistose materials that has a high penetration force not only in the vertical direction, and consequently allows easy separation of two facing cutting surfaces of a block of slate or other schistose materials, even when inserts of tough materials resist separation along the selected cutting plane.
• Another object of the invention is to provide a cutting apparatus for use in machines for cutting blocks of schistose materials, that allows simple and quick replacement of the cutting blades, while minimizing the time required to complete replacements.
• the invention relates to a cutting apparatus for machines for cutting blocks of schistose materials as defined by the characteristics of claim 1 .
• Figure 1 is a schematic front view of a cutting apparatus for use in machines for cutting blocks of schistose materials according to the invention, at the start of a cutting cycle;
• Figure 2 is a schematic front view of a cutting apparatus for use in machines for cutting blocks of schistose materials according to the invention, in an intermediate step of a cutting cycle;
• Figure 3 is a schematic front view of a cutting apparatus for use in machines for cutting blocks of schistose materials according to the invention, in a final step of a cutting cycle;
• Figure 4 is a schematic cross-sectional view of an embodiment of the lock means for removably locking a cutting blade of the cutting apparatus of the invention, in a blade unlocking configuration;
• Figure 5 is a schematic cross-sectional view of an embodiment of the lock means for removably locking a cutting blade of the cutting apparatus of the invention, in a blade locking configuration.
• numeral 1 generally designates a cutting apparatus for use in machines for cutting blocks 2 of schistose materials, namely slate.
• the cutting apparatus comprises a pressing unit 3, such as a cylinder (not shown) which vertically moves a crossbar 4 guided by two guide members, typically two parallel columns 5 and is counteracted, as it descends, by compression-loadable elastic members 6, disposed at the periphery of the columns 5.
• a pressing unit 3 such as a cylinder (not shown) which vertically moves a crossbar 4 guided by two guide members, typically two parallel columns 5 and is counteracted, as it descends, by compression-loadable elastic members 6, disposed at the periphery of the columns 5.
• the latter support a box-like support 7 that defines therein a chamber 8 having an access door 9 through which compressed air is typically fed from a source, not shown and known to the skilled person.
• a blade 10 is slidably mounted in the chamber 8 between seals 15 and, as shown in Figures 4 and 5, is fixed to a support member 1 1 by removable lock means 12, to allow replacement of the blade 10 as needed.
• the blade 10 has an overall height designated as "h” and a cutting face 12 with a plurality of parallel notches 13 and 14 formed therein.
• the figure particularly shows that the notches 13 have a height "hi " and the notches 14 have a height "h2" that is greater than the height "hi " but smaller than the height "h” of the blade 10.
• the block 2 of schistose material, here slate, to be cut lies on a support of a cutting machine (not shown) and, during cutting is placed between two side walls 16 and 17 abutting against the sides of the block 2 and preventing compressed air from leaking out of the two cutting surfaces from either side.
• the means for locking or unlocking the blade 10 to and from the support member 1 1 comprise a prismatic support body 18 in which a hollow seat 19 is formed, for receiving the blade 10.
• the hollow seat 19 has an inclined side wall 20 along which a prismatic clamping body 21 slides, which body has an inclined face 22 facing the inclined wall 20 and designed to slide therealong from a locking position ( Figure 5) to an unlocking position ( Figure 4) and vice versa, by being pushed by a screw 23 which extends through the prismatic clamping body 21 without being tightened therein, but by simply abutting thereagainst with its head 23a, and which engages in a threaded seat 24 formed in the prismatic body 18.
• the operation of the cutting apparatus for use in machines for cutting blocks of schistose materials is as follows: a slate block 2 is placed in a known manner on the bed of a machine for cutting schistose stone materials.
• the pressing unit 3 is fully raised from the block 2 in an idle position and is supported by a movable carriage of the machine, which places it in a predetermined initial cutting section.
• the blade 10 is in a fully extracted state with respect to the chamber 8 of the box-like support 7, as shown in Figure 1 .
• the cutting step starts.
• the pressing unit 3 moves toward the block 2 until the cutting edge of the blade 10 abuts against the upper face of the block 2 (see Figure 2) and the blade 10 is progressively retracted into the chamber 8 in which compressed air has been fed through the access door 9.
• the thrust of the pressing unit 3 causes the cutting face 12 of the blade 10 to penetrate the block 2 in a direction that is substantially parallel to a natural cleavage plane of the slate block 2.
• This will generate a front of compressed air that will cooperate with the blade 10 to progressively separate the cutting surfaces from the center to the sides thereof, said front being directed partly toward the base of the block 2 and partly toward its sides, thereby acting as a separating wedge.
• the invention is susceptible to a number of changes and variants within the inventive concept.

Landscapes

• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Mechanical Engineering (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)
• Nonmetal Cutting Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=48747635

Family Applications (1)

Country Status (2)

Citations (2)

Family Cites Families (4)

• 2012
  • 2012-05-21 ES ES201230757A patent/ES2431892B1/es not_active Expired - Fee Related
• 2013
  • 2013-05-21 WO PCT/IB2013/054172 patent/WO2013175398A1/en active Application Filing

Patent Citations (2)

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