Stone cutting device

Abstract

A stone cutting device configured to cut a workpiece with a plurality of cutting tools by swinging the cutting tools within a predetermined angle range. Each of the cutting tools includes: a blade extending in a length direction of the workpiece; and at least one cutting tip disposed on an end of the blade and protruding from the blade in a width direction of the blade so as to cut the workpiece while being reciprocated in a swinging motion. The stone cutting device includes a frame unit configured to combine and reciprocate the cutting tools and individually adjust tension in each of the cutting tools. The frame unit includes an actuator applying tension to the cutting tools so as to apply a load of 8 tons to 27 tons to each of the cutting tools.

Claims

1. A stone cutting device configured to cut a workpiece, the stone cutting device comprising: a plurality of cutting tools that cut the workpiece by swinging within a predetermined angle range, each of the cutting tools comprising a blade extending in a length direction of the workpiece, and at least one cutting tip disposed on an end of the blade and protruding from the blade in a width direction of the blade so as to cut the workpiece while being reciprocated in a swinging motion; and a frame unit configured to combine and reciprocate the cutting tools and individually adjust tension in each of the cutting tools, wherein the frame unit comprises an actuator applying tension to the cutting tools so as to apply a load of 8 tons to 27 tons to each of the cutting tools, and wherein the actuator has at least one high-strength hydraulic pipe or an increased hydraulic pressure transmission area to endure the tension of the cutting tools while maintaining an interval between blades of the cutting tools ranging from 15 millimeters to 30 millimeters.

2. The stone cutting device of claim 1, wherein the frame unit comprises a body unit comprising a plurality of actuators respectively corresponding to the cutting tools, and the body unit respectively couples the cutting tools to the actuators.

3. The stone cutting device of claim 1, wherein the workpiece comprises granite.

4. The stone cutting device of claim 1, wherein the stone cutting device comprises spacers maintaining gaps between the cutting tools, the spacers constraining the cutting tools from moving in a width direction of the cutting tools and allowing the cutting tools to move in a length direction of the cutting tools.

5. A stone cutting device configured to cut a workpiece with a plurality of cutting tools by swinging the cutting tools within a predetermined angle range, each of the cutting tools comprising a blade extending in a length direction of the workpiece, and at least one cutting tip disposed on an end of the blade and protruding from the blade in a width direction of the blade so as to cut the workpiece while being reciprocated in a swinging motion, the stone cutting device comprising: a frame unit configured to combine and reciprocate the cutting tools and individually adjust tension in each of the cutting tools; and spacers maintaining gaps between the cutting tools, the spacers having bodies disposed between the cutting tools and integrally combined with both widthwise ends of the bodies being clamped, the bodies including accommodation portions to receive the cutting tools, the accommodation portions having accommodation recess portions formed in sides of the bodies and having a depth corresponding to a thickness of the blades, wherein the gaps are formed in the spacers between the accommodation recess portions of the bodies and the blades, the spacers constraining the cutting tools from moving in a width direction of the cutting tools and allowing the cutting tools to move in a length direction of the cutting tools.

6. The stone cutting device of claim 5, wherein the accommodation portions comprise jaw parts coupled to sides of the bodies and having thicknesses corresponding to thicknesses of the cutting tools.

7. The stone cutting device of claim 5, wherein the frame unit comprises actuators applying tension to the cutting tools so as to apply a load of 8 tons to 27 tons to each of the cutting tools.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic view illustrating a process of cutting a workpiece using a reciprocating-type stone cutting device including a plurality of blades.

(2) FIGS. 2A and 2B are a side view and a front view illustrating a process of cutting a workpiece with the stone cutting device.

(3) FIGS. 3A and 3B are schematic views illustrating how a cutting tool is deformed during a stone cutting process using the stone cutting device.

(4) FIGS. 4A and 4B are cross-sectional views respectively illustrating a steel shot type cutting tool of a stone cutting device of the related art and a cutting tip type cutting tool of a stone cutting device of the related art.

(5) FIG. 5 is a cross-sectional view illustrating spacers of a cutting tool of a stone cutting device of the related art.

(6) FIG. 6 is a cross-sectional view illustrating a stone cutting device according to an exemplary embodiment of the present disclosure.

(7) FIG. 7 is a plan view illustrating the stone cutting device according to the exemplary embodiment of the present disclosure.

(8) FIG. 8 is a side view illustrating a cutting tool of the stone cutting device according to the exemplary embodiment of the present disclosure.

(9) FIG. 9 is a cross-sectional view illustrating spacers disposed between cutting tools of the stone cutting device according to the exemplary embodiment of the present disclosure.

(10) FIGS. 10A and 10B are cross-sectional views illustrating a modification of the spacers disposed between the cutting tools of the stone cutting device, according to another exemplary embodiment of the present disclosure.

(11) FIGS. 11A to 11D are graphs illustrating the thicknesses of cut workpieces with respect to degrees of tension in blades of the stone cutting device according to examples.

BEST MODE

(12) Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The disclosure may, however, be exemplified in many different forms and should not be construed as being limited to the specific embodiments set forth herein. In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements.

(13) FIG. 6 is a cross-sectional view illustrating a stone cutting device 110 according to an exemplary embodiment of the present disclosure, FIG. 7 is a plan view illustrating the stone cutting device 110 according to the exemplary embodiment of the present disclosure, and FIG. 8 is a side view illustrating a cutting tool 120 of the stone cutting device 110 according to the exemplary embodiment of the present disclosure. FIG. 9 is a cross-sectional view illustrating spacers 140 disposed between cutting tools 120 of the stone cutting device 110 according to the exemplary embodiment of the present disclosure.

(14) Referring to FIGS. 6 to 9, the stone cutting device 110 is configured to cut a workpiece 100 by reciprocating the cutting tools 120 between both sides of the workpiece 100 in the length direction of the workpiece 100 such that the cutting tools 120 may cut the workpiece 100 while contacting the workpiece 100.

(15) A representative example of the stone cutting device 110 is a reciprocating-type multi-blade frame gang saw. In the current exemplary embodiment, the cutting tools 120 of the stone cutting device 110 may cut the workpiece 100 while swinging within a predetermined angle range.

(16) The stone cutting device 110 of the current exemplary embodiment may include the cutting tools 120 extending in the length direction of the workpiece 100 and may be configured to cut the workpiece 100 while reciprocating along the workpiece 100. The cutting tools 120 may be coupled to a frame unit 130.

(17) In the state in which the cutting tools 120 are coupled to the frame unit 130, the frame unit 130 may reciprocate the cutting tools 120 such that the cutting tools 120 may make contact with the workpiece 100 and cut the workpiece 100.

(18) In addition, the frame unit 130 may individually adjust tension in each of the cutting tools 120.

(19) The frame unit 130 may include at least one pair of pillars 136 set up at both sides of the workpiece 100. For example, the pillars 136 may be disposed in positions close to four corners of the workpiece 100.

(20) In addition, arm units 138 capable of swinging within a predetermined angle range may be provided on the pillars 136. In addition, the arm units 138 may include bodies 132 combining the cutting tools 120.

(21) In addition, the arm units 138 may be moved upwardly and downwardly. For example, the arm units 138 may be moved downwardly at a predetermined speed by a driving unit.

(22) Owing to the arm units 138, when the workpiece 100 is cut with the cutting tools 120, the cutting tools 120 may be intermittently brought into contact with the workpiece 100 in association with the swinging motion of the cutting tools 120.

(23) The bodies 132 may fix front and rear ends of the cutting tools 120 and may apply a constant degree of tension to the cutting tools 120. To this end, the bodies 132 may include a plurality of actuators 134 configured to apply tension to the cutting tools 120, respectively.

(24) In the current exemplary embodiment, compared to actuators of the related art, the actuators 134 may apply a relatively high degree of tension to the cutting tools 120, for example, on the level of about 1,000 bars. To this end, the internal hydraulic pressure of the actuators 134 may be increased.

(25) In the current exemplary embodiment, for example, the actuators 134 may apply tension to the cutting tools 120 so as to apply a load of about 8 tons to 15 tons to the cutting tools 120. If the internal hydraulic pressure of the actuators 134 is increased to 1,000 bars, a tension of about 27 tons may be applied to the cutting tools 120.

(26) To this ends, high-strength hydraulic pipes may be used, or hydraulic pressure transmission areas may be increased. Furthermore, the frame unit 130 may be configured to have a durable structure and a high degree of strength, and a reinforcement structure may be further used, such that the frame unit 130 may endure the increase in the tension of the cutting tools 120.

(27) There is a limit to increasing the diameters of the actuators 134 to increase the magnitude of loads that the bodies 132 can apply. The reason for this is that since the interval between blades 122 ranges from 15 mm to 30 mm, spaces for applying tension to the blades 122 are narrow. Therefore, instead of increasing the diameters of the actuators 134, the internal hydraulic pressure of the actuators 134 may be increased to increase the magnitude of loads that the actuators 134 can apply.

(28) The cutting tools 120 may include the blades 122 extending in the length direction of the workpiece 100.

(29) The blades 122 may be formed of a high-tensile steel sheet to sufficiently resist tension applied by the actuators 134, for example, on the level of about 27 tons. For example, if the blades 22 of the cutting tools 120 are vibrated at a rate of about 150 times per minute, it may take 40 hours for the blades 122 to cut about 2 m of granite, and if it is assumed that the blades 122 are usable up to about 20 times, the blades 122 may be subjected to high cycle fatigue (10.sup.6 cycles to 10.sup.7 cycles)

(30) That is, the blades 122 have to endure such high cycle fatigue environments without breakage. In addition, deformation may be locally concentrated in cutting tips of the blades 122. Therefore, dimensions and steel for forming the blades 22 may be selected in consideration of a safety factor so that the blades 22 may resist the pressures of such environments.

(31) For example, blades of cutting tools using steel shot may have a thickness of 4 mm and a height of 100 mm, and steel having a tensile strength of about 85 kg/mm.sup.2 may be used to form the blades. If it is assumed that the fatigue strength of the blades is about 40% of the tensile strength of the blades, and a safety factor of 0.8 is applied, the blades may be resistant to tension causing a load of about 110 kN, that is, about 11 tons.

(32) In the current exemplary embodiment, at least one cutting tip may be provided on each of the blades 122 of the cutting tools 120 so as to increase cutting force and the rate of cutting. In this case, cutting may be substantially carried out by the cutting tips without using steel shots.

(33) For example, the cutting tips may be coupled to ends of the blades 122 and may be thicker than the blades 122. That is, the cutting tips may protrude from the blades 122 in the width direction of the blades 122. In this state, the cutting tips may be brought into contact with the workpiece 100 to cut the workpiece 100.

(34) As described above, the blades 122 having the cutting tips may have a thickness of 3.5 mm and a height of 180 mm and may be formed of steel having a tensile strength of 1,300 kg/mm.sup.2.

(35) In the current exemplary embodiment, cutting is substantially performed by the cutting tips of the blades 122, and thus the blades 122 may be formed of material having tensile strength higher than that used to form blades of cutting tools that use steel shots. That is, the blades 122 may be formed of high-tensile steel, and thus the blades 122 may be relatively thin.

(36) In the current exemplary embodiment, if it is assumed that the fatigue strength of the blades 122 is about 40% of the tensile strength of the blades 122, and a safety factor of 0.8 is applied, the blades 122 may be resistant to tension causing a load of about 266 kN, that is, about 27 tons.

(37) Furthermore, in the current exemplary embodiment, since the maximum load that the blades 122 of the cutting tools 120 can endure is increased, it may be preferable that the blades 122 have a height of about 180 mm.

(38) If the heights of the blades 122 are increased, the degree of tension that the blades 122 can endure may be affected. Blades using steel shot and having the same height as the blades 122 may endure tension causing a force or load of about 196 kN, that is, 20 tons. That is, blades using steel shot and having the same dimensions as the blades 122 may endure a load which is lower by about 35% than a load that the blades 122 using the cutting tips can endure. In general, blades may endure a greater load if the dimensions of the blades, such as the height, are increased. In this case, however, the weight and size of an entire system may increase, and thus there is a limit to increasing the dimension of blades.

(39) Therefore, blades of a frame gang saw using cutting tips may be formed of high-tensile steel to increase an amount of tension that the blades can endure.

(40) For example, the actuators 134 may apply about 300 bars of tension to the blades 122 under conventional operating conditions, which may cause a load of about 8 tons to about 10 tons. If the tension applied from the actuators 134 to the blades 122 is doubled to about 600 bars, the blades 122 may generate a load of about 16 tons to about 20 tons.

(41) Under these conditions, conventional blades using steel shots may fracture because the conventional blades are not able to endure a load of about 20 tons (about 11 tons if the fatigue strength and safety factor of the conventional blades are considered).

(42) According to the current exemplary embodiment, however, the blades 122 including the cutting tips are able to endure a load of about 27 tons when the fatigue strength and safety factor of the blades 122 are considered. That is, although the amount of tension applied by the actuators 134 is tripled to about 900 bars, the blades 122 may not fracture.

(43) In addition, if the heights of the blades 122 including the cutting tips are increased to a range of about 250 mm to about 300 mm, the blades 122 may endure up to about 1300 bars of tension applied by the actuators 134.

(44) In addition, the cutting tools 120 may include extension members 124 to transmit tension applied by the actuators 134. The extension members 124 may be connected to transmit tension from the actuators 134 to the blades 122.

(45) In addition, the spacers 140 may be disposed between the blades 122 of the cutting tools 120, and thus the blades 122 coupled to the frame unit 130 may be maintained at regular intervals.

(46) In the current exemplary embodiment, the spacers 140 may constrain the movement of the blades 122 in the width direction of the blades 122 but may allow for the movement of the blades 122 in the length direction of the blades 122. Therefore, owing to this constraint of the blades 122 in the width direction, the blades 122 may not undergo deformation such as bending or twisting.

(47) In addition, since the blades 122 are allowed to move in the length direction thereof, the magnitude of tension of each of the blades 122 may be individually adjusted.

(48) That is, in the current exemplary embodiment, the blades 122 of the cutting tools 120 that actually receive tension are constrained in the width thereof by the spacers 140 but are allowed to move in the length direction thereof. Therefore, a high degree of tension may be applied to the blades 122.

(49) If a high degree of tension is applied to the blades 122, the resilience of the blades 122 may increase, and thus the workpiece 100 may be cut with low thickness deviation and high cutting quality.

(50) Both widthwise ends of the spacers 140 may be held by clamps so that the spacers 140 may be combined while holding the blades 122.

(51) The spacers 140 may include bodies 142 disposed on sides of the blades 122, and the bodies 142 may include accommodation portions. When the spacers 140 are combined, the accommodation portions may accommodate the cutting tools 120, that is, the blades 122 extending in the length direction of the cutting tools 120, in a state in which the blades 122 are constrained from moving in the width direction thereof but allowed to move in the length direction thereof.

(52) In the current exemplary embodiment, the accommodation portions may include accommodation recess portions 144 formed in sides of the bodies 142 and having a depth corresponding to the thickness of the blades 122.

(53) The spacers 140 are combined in such a manner that a portion of a body 142 located around the accommodation recess portion 144 of the body 142 is supported by a rear side of another body 142. Therefore, the blades 122 inserted into the accommodation recess portions 144 may be constrained from moving in the width direction thereof. In addition, since the bodies 142 are arranged in such a manner that a body 142 is supported by the rear side of another body 142, the bodies 142 do not press the blades 122 in the width direction of the blades 122 and do not constrain the blades 122 in the length direction of the blades 122.

(54) To this end, gaps may be formed between the accommodation recess portions 144 of the bodies 142 and the blades 122.

(55) For example, a dimensional tolerance between the accommodation recess portions 144 and the blades 122 may be from ?0.1 mm to 0.5 mm.

(56) If the dimensional tolerance between the accommodation recess portions 144 and the blades 122 is greater than 0.5 mm, the blades 122 may not be stably constrained.

(57) Although it is preferable that the dimensional tolerance between the accommodation recess portions 144 and the blades 122 is greater than 0 mm, the dimensional tolerance may have a value up to ?0.1 mm due to an allowable error of tension applied to the blades 122. That is, if the dimensional tolerance between the accommodation recess portions 144 and the blades 122 is 0 mm, the blades 122 may not be constrained by the spacers 140, and thus tension applied by the actuators 134 may be transmitted to the blades 122 intact. If the dimensional tolerance between the accommodation recess portions 144 and the blades 122 is less than 0 mm, the blades 122 may be somewhat constrained by the spacers 140, and thus tension may not be completely transmitted to the blades 122. However, even in this case, if the dimensional tolerance between the accommodation recess portions 144 and the blades 122 is ?0.1 mm or greater, sufficient tension may be applied to the blades 122.

(58) In the current exemplary embodiment, the accommodation portions of the spacers 140 may have any other structure instead of having the accommodation recess portions 144.

(59) FIGS. 10A and 10B are cross-sectional views illustrating a modification of the spacers 140 disposed between the cutting tools 120 of the stone cutting device 110 according to another exemplary embodiment of the present disclosure.

(60) Referring to FIGS. 10A and 10B, in the this exemplary embodiment, a spacer 240 may include a body 242, and jaw parts 244 corresponding to the thickness of the blade 122 may be coupled to the body 242.

(61) Sides of the jaw parts 244 may be coupled to a side of the body 242 such that the jaw parts 244 may be disposed above and below the blade 122. In addition, other sides of the jaw parts 244 may be supported by a side of another body 242 (not shown) clamped to the body 242.

(62) The jaw parts 244 may be coupled to the body 242 using fasteners such as bolts 245, and the body 242 may include coupling holes 242a to receive the bolts 245 inserted through penetration holes 244a of the jaw parts 244.

(63) Stone may be cut with the stone cutting device 110 as follows. FIGS. 11A to 11D are graphs illustrating the thicknesses of cut workpieces with respect to degrees of tension in the blades 122 of the stone cutting device 110 according to examples.

(64) First, a stone workpiece is placed in the stone cutting device 110. The cutting tools 120 are coupled to the stone cutting device 110 in the length direction of the stone workpiece. The cutting tools 120 are integrally combined with each other using clamps with the spacers 140 being disposed therebetween.

MODE FOR INVENTION

Example 1

(65) In Example 1, spacers were disposed between cutting tools, and the cutting tools were clamped together with the spacers. Thus, tension in the cutting tools could not be adjusted.

(66) If excessive tension is applied to the cutting tools, some of the cutting tools may fracture because of excessive tension, and the remainder of the cutting tools may undergo deformation such as bending due to insufficient tension.

(67) FIG. 11A is a graph illustrating thicknesses of cut workpieces with respect to tension in blades in Example 1.

(68) As illustrated in FIG. 11A, the hydraulic pressure of actuators of a stone cutting device was about 300 bars, and a tension of about 7.5 tons was applied to the blades.

(69) When stone was cut under these conditions of Example 1, a high thickness deviation was observed.

Example 2

(70) In Example 2, the hydraulic pressure of actuators was about 300 bars as in Example 1, and a tension of about 7.5 tons was applied to blades of cutting tools.

(71) The spacers described in the exemplary embodiment of the present disclosure were coupled between the blades. The spacers maintained gaps between the blades without restricting tension applied to the blades, and thus tension could be distributed in the blades of a stone cutting device intact. That is, although tension applied by the stone cutting device was not increased, the effect of increasing tension in the blades could be obtained.

(72) FIG. 11B is a graph illustrating the thicknesses of cut workpieces with respect to tension in the blades in Example 2.

(73) As illustrated in FIG. 11B, when stone was cut under the above-described conditions of Example 2, thickness deviation was lower than in Example 1.

(74) In Example 2, the blades of the cutting tools were not completely constrained by the spacers, and thus tension could be applied to the blades intact. Therefore, when stone was cut into slabs using the cutting tools, tension could be applied to the cutting tools without loss, and thus the thickness deviation of slabs was reduced.

(75) In the stone cutting device, however, the cutting tools and the spacers were tightly coupled together, and thus the degree of tension in each of the cutting tools could not be individually adjusted. In Example 2, if an amount of tension higher than the above-mentioned value is applied, the possibility of blades fracturing may increase, and workability may not improve.

Example 3

(76) In example 3, the stone cutting device of the exemplary embodiment of the present disclosure was used while applying a degree of tension greater than the above-mentioned degree of tension by about 100%. That is, the hydraulic pressure of the improved actuators was about 600 bars in Example 3.

(77) FIG. 11C is a graph illustrating the thicknesses of cut workpieces with respect to tension in the blades according to Example 3.

(78) As illustrated in FIG. 11C, the hydraulic pressure applied to the blades was increased to about 600 bars during a stone cutting process. In this case, a degree of tension of about 15 tons was applied to the blades.

(79) In the stone cutting device, as tension in the blades of cutting tools increased, the thickness deviation of cut workpieces decreased.

Example 4

(80) In Example 4, the stone cutting device of the exemplary embodiment of the present disclosure including spacers between the cutting tools was used. The cutting tools were clamped in such a manner that the cutting tools were constrained from moving in the width direction thereof by the spacers while being allowed to move in the length direction thereof.

(81) Therefore, tension in each of the cutting tools could be individually adjusted by taking the states of the blades of the cutting tools into consideration, and thus tension in the blades was not insufficient or excessive.

(82) In Example 4, about 600 bars of hydraulic pressure was applied to the blades during a stone cutting process. In this case, the blades were constrained from moving in the width direction of the blades, and tension was applied from the improved actuators to the blades intact. Thus, tension in the blades was about 15 tons.

(83) FIG. 11D is a graph illustrating the thicknesses of cut workpieces with respect to tension in the blades in Example 4.

(84) As illustrated in FIG. 11D, in Example 4, when a hydraulic pressure of about 600 bars was applied to the cutting tools, tension in each of the blades could be individually adjusted. Thus, stone workpieces could be cut in a state in which high tension was applied to the blades. In addition, since tension in each of the cutting tools could be individually adjusted, the cutting tools were not easily fractured, and thus stone workpieces could be cut with low thickness deviation.

(85) While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.