Background Art [2] A wood beam 2 can be easily cut into a wood beam having a circular cross-section by approaching a cutting tool to the outer circumference of the wood beam 2 while the wood beam 2 is rotated as shown in Figs. 1 and 2. However, if the wood beam 1 has a curved shape, as shown in Figs. 3 and 4, the curve-shaped wood beam 1 cannot be cut into a wood beam having a circular cross-section during the rotation in the con- ventional manner.

[3] In other words, a rafter, used in a traditional Korean-style house, must have a circular cross-section. However, since the curve-shaped wood beam 1 cannot be formed by a machine due to its curved shape, but only manually, so that it is very difficult for the expert to cut the curve-shaped wood into the linear circular cross- sectional rafter manually. Moreover, manual production demands a lot of time and manpower.

[4] Disclosure of Invention Technical Problem [5] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a wood cutting machine in which a curve-shaped wood is fixed, and a cutting tool is rotated around the outer dr- cumference of the curve-shaped wood while being moved along the central axis so as to cut the curve-shaped wood into a wood beam having a circular cross-section.

[6] Technical Solution [7] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a curve-shaped wood cutting machine including a fixing device fixed at the side of a frame, for fixing a center of the side of a curve-shaped wood beam, a temporary fixing device, moved on the frame along the rails, for fixing a center of the other side of the curve-shaped wood beam, a moving device moved laterally along the rails in the state that the curve-shaped wood beam is inserted into the central portion of the moving device, a cutting device installed in the moving device and having cutting tools for cutting the curve-shaped wood beam, a diameter adjusting device for adjusting the diameter of the curve-shaped wood beam by moving the cutting tools of the cutting device toward a central axis of the curve- shaped wood beam to be cut, a rotation device for rotating the cutting device and the diameter adjusting device, and a laterally moving device, installed to the moving device, for moving the cutting tools in the lateral direction perpendicular to the lon- gitudinal direction of the curve-shaped wood beam.

[8] The cutting tools move along the wood beam so as to produce a circular cross- sectional wood beam.

[9] Advantageous Effects [10] As described above, the present invention relates a curve-shaped wood cutting machine for forrring a curve-shaped wood as it is to have a circular cross-section.

According to the curve-shaped wood cutting machine of the present invention, the curve-shaped wood can be formed uniformly by the machine. Moreover, even one who is not an expert can easily form the curve-shaped wood beam using the wood cutting machine of the present invention.

[11] According to the present invention, since time required to cut the curve-shaped wood is reduced and quality of the finished wood beam can be enhanced, and since rafters can be produced uniformly, costs and time for producing the rafter or wood beams can be reduced.

[12] Moreover, by using the wood cutting machine according to the present invention, the curve-shaped wood can be also formed, so that the produced curve-shaped wood beam can be utilized for various purposes.

[13] Brief Description of the Drawings [14] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [15] Fig. 1 is a perspective view illustrating a cross-section of a conventional linear wood beam; [16] Fig. 2 is a cross-sectional view illustrating cutting of a conventional wood beam; [17] Fig. 3 is a perspective view illustrating a cross-section of a curve-shaped wood beam cut in accordance with the present invention; [18] Fig. 4 is a cross-sectional view illustrating a curve-shaped wood beam cut in accordance with the present invention; [19] Fig. 5 is a front view illustrating a wood cutting machine according to the present invention; [20] Fig. 6 is a front view illustrating the installation of the curve-shaped wood in the wood cutting machine according to the present invention; [21] Fig. 7 is an inner cross-sectional view of a moving means of the wood cutting machine according to the present invention; [22] Fig. 8 is a rear side view of the moving means of the wood cutting machine according to the present invention; [23] Fig. 9 is a side cross-sectional view of the moving means of the wood cutting machine according to the present invention; [24] Fig. 10 is a side view of a temporary fixing means of the wood cutting machine according to the present invention; [25] Fig. 11 is an operative view illustrating a diameter adjusting means of the wood cutting machine according to the present invention; [26] Fig. 12 is a front view of a rotating plate of the wood cutting machine according to the present invention; and [27] Fig. 13 is an operative view illustrating a supporting device of the wood cutting machine according to the present invention.

[28] Best Mode for Carrying Out the Invention [29] A curve-shaped wood cutting machine according to the present invention includes a fixing device 20 mounted at the side of a fixed frame 10, a temporary fixing device 30 mounted at the other side of the fixed frame 10, which moves on rails 11 mounted to the upper side of the fixed frame 10, and probes 21 and 31 installed at the temporary fixing device 30 which are pinned to both central points of a curve-shaped wood so as to fix the curve-shaped wood.

[30] The frame 10 is provided with a moving device 50 at the central portion of which the wood beam 1 passes through. The moving device 50 moves in the longitudinal direction of the frame 10 along the rails 11, and is installed with cutting devices 60 for cutting the wood beam 1 into a circular cross-sectional wood beam by being rotated around the outer circumference of the wood beam 1 placed at the central axis. The cutting devices 60 can move toward the center of the wood beam 1 by means of a diameter adjusting device 80 so as to cut the wood beam while adjusting the diameter of the wood beam 1. The cutting devices 60 and the diameter adjusting device 80 are rotated within the moving device 50 by a rotation device 70.

[31] In the moving device 50, a laterally moving device 90, moved laterally and engaged with rails 52, is installed to the upper side of a forward and rearward moving plate 51, which is engaged with the rails 11. The moving device 50 is engaged with the laterally moving device 90, so that the moving device 50 can freely move in the lon- gitudinal direction and in the lateral direction of the frame 10.

[32] In the structure of the wood cutting machine according to the present invention, after the curve-shaped wood beam 1 is fixed at the side of the fixing device 20 through the central portion of the moving device 50, if the temporary fixing device 30 moves so as to fix the other side of the curve-shaped wood beam 1 and the cutting devices 60 of the moving device 50 are driven, the cutting devices 60 are revolved around the outer circumference of the curve-shaped wood beam 1 while the cutting tools 63 are rotated so as to cut the curve-shaped wood beam 1. The moving device 50 is moved forward while the curve-shaped wood beam 1 is cut.

[33] During the cutting, the laterally moving device 90 is driven at the curved position of the curve-shaped wood beam 1 so that the cutting devices 60 move laterally and the position of the cutting tool 63 is changed so as to cut the curve-shaped portion of the curve-shaped wood beam 1. When the cutting is finished, the temporary fixing device 30 is moved and the finished wood beam 1 is taken out.

[34] The curve-shaped wood cutting machine according to the present invention will be described in detail with reference to the accompanying drawings as follows.

[35] The curve-shaped wood cutting machine according to the present invention includes the fixed frame 10 having an empty central portion and installed with the rails 11 at both sides thereof, the fixing device 20 is mounted at the side of the fixing frame 10 so as to fix the center of the side of the wood beam 1 by the probe 21, and the temporary fixing device 30 is moved forward and rearward along the rails 11 on the frame 10 so as to fix the center of the other side of the wood beam 1 by the probe 31.

[36] The temporary fixing device 30 can be moved along the rails 11 by a motor 33.

The temporary fixing device 30 is moved so that the probe 21 comes in contact with the side of the wood beam 1, then the probe 31 is moved by a handle 32 so as to firmly fix the wood beam 1. At the upper central portion of the frame 10, supports 40 can be moved upwardly and downwardly by air cylinders 41 so as to support the wood beam 1, while the air cylinders 41 can be lowered and raised by other air cylinders 42.

[37] The moving device 50 moved forward and rearward along the fixed frame 10 connects the forward and rearward moving plate 51 to the upper side of the rails 11 while a screw shaft 12 is fixed at the lower side of the forward and rearward moving plate 51, so that the forward and rearward moving plate 51 can move forward and rearward along the rails 11 due to the rotation of a screw nut by a motor 53. The forward and rearward moving plate 51 is formed with rails 52 at the upper side thereof, so as to connect a laterally moving plate 91 of the laterally moving device 90 to the rails 52. The laterally moving plate 91 is engaged with the screw shaft 92 and moved laterally along the rails 52 due to the rotation of the screw shaft 92 by the motor 93.

[38] The laterally moving plate91 is fixed with a body 50'of the moving device 50 at the upper side thereof. The moving device 50 is associated with a rotating plate 73 at the inside of the moving device 50, in which the rotational force generated by a motor 71 of the rotation device 70 is transmitted through belts 72, so as to rotate the rotation plate 73 using the motor 71. The wood beam 1 passes through the center of the rotation plate 73, and at the front side of the rotation plate 73, the cutting devices 60 are sym- metrically installed along with the diameter adjusting device 80.

[39] In other words, moving plates 81 are engaged at the front side of the rotation plate 73, such that the moving plates 81 can move upward and downward due to the rotation of the screw shaft 82. Fixed plates 62 are fixed at the front side of the moving plates 81 perpendicular to the moving plates 81. The fixed plates 62 are installed with motors 61 at the upper sides thereof, and the cutting tools 63 at the lower sides thereof so as to rotate the cutting tools at a high speed by means of the rotational force of the motors 61.

[40] The rotation plate 73 is installed with the diameter adjusting device 80 at the front side thereof so as to move the cutting tools 63 toward the central portion. The rotational force of the motors 83 is transmitted to a rotational shaft 84 through the belts. The rotational force of the rotational shaft 84 is transmitted to a rotational shaft 85 via bevel gears, and the rotational force of the rotational shaft 85 is transmitted to the screw shaft 82 via the bevel gears, so that the cutting tools 63 can move upward and downward in accordance with the rotational direction and the driven time of the motors 82.

[41] The process of cutting the curve-shaped wood beam 1 into the curve-shaped wood beam 1 having a circular cross-section by using the wood cutting machine according to the present invention, will be described in detail.

[42] First, the moving device 50 is moved to the position at which the fixing device 20 is located, and the temporary fixing device 30 is moved to the opposite position, so as to secure a space between the fixing device 20 and the temporary fixing device 30.

Next, the curve-shaped wood beam 1 is lifted by a crane and pushed into the fixing device 20 through a hole formed at the central portion of the moving device 50 so as to allow the side of the curve-shaped wood beam 1 come in contact with the probe 21.

The probe 21 comes in contact with the center of the side of the curve-shaped wood beam 1, the air cylinders 42 are operated to raise the supports 40 so as to support the lower side of the curve-shaped wood beam 1, and the probe 31 of the temporary fixing device 30 is inserted into the center of the other side of the curve-shaped wood beam 1.

[43] In other words, after the curve-shaped wood beam 1 passes through the moving device 50 and the probe 21 of the fixing device is inserted into the center of the side thereof, the temporary fixing device 30 is moved toward the motor 33 and the handle 32 is rotated by hand so as to protrude the probe 31, so that the probe 31 is inserted into the center of the side of the curve-shaped wood beam 1 and the air cylinders 42 raise the supports 40 so as to support the lower side of the curve-shaped wood beam 1.

[44] When the motor 33 is rotated, the temporary fixing device 30 moves forward and rearward along the upper rails 11 of the frame 10, due to the driving force generated by the rotation of rack gear 34 which is engaged with a rack 13 fixed at the lower side of the frame 10. When the temporary fixing device 30 arrives at the desired position, the handle 32 is rotated so as to press the probe 31 against the center of the side of the curve wood beam 1.

[45] After fixing the curve-shaped wood beam 1, the motor 71 of the rotation device 70 is driven so as to rotate the rotational plate 73, so that the cutting devices installed in the moving device 50 are rotated together with the rotational plate 73. Thus, the cutting tools 60 are rotated around the outer circumference of the curve-shaped wood beam 1.

[46] The motor 83 of the diameter adjusting device 80 is driven so as to move the moving plates 81 upward or downward by the screw shaft 82. Thus, the cutting tools 63 are substantially moved upward or downward so as to cut the curve-shaped wood beam 1 to a desired diameter. The cutting tools 63 cut the surface of the curve-shaped wood beam 1, so that the curve-shaped wood beam 1 with the desired diameter can be formed.

[47] At this time, since the rotational force of the motors 61 is transmitted to the cutting tools 63, the cutting tools 63 can be rotated at a high speed.

[48] In other words, since the cutting tools 63 are rotated at a high speed by the motors 61 and the rotational plate 73 is also rotated by the motor 71, the cutting tools 63 are rotated around the outer circumference of the curve-shaped wood beam 1. Ac- cordingly, the cutting tools 63 are revolved around the outer circumference of the curve-shaped wood beam 1 and are rotated.

[49] When the cutting tools 63 are rotated, the outer surface of the curve-shaped wood beam 1 is cut off and the curve-shaped wood beam is given a circular cross-section. In this state, the motor 53 is driven so as to move the moving device 50 along the screw shaft 12, and the motor 93 is driven so as to move the laterally moving plate 91 laterally, so that the cutting tools 63 cut the curve-shaped wood beam 1 while moving forward or rearward and laterally.

[50] In accordance with the degree to which the curve-shaped wood beam 1 is cut, the motor 53 is driven so that the cutting tools 63 of the cutting device 60 advance so as to continuously cut the curve-shaped wood beam 1. At this time, since the wood beam 1 is curved, the motors 61 are driven so as to move the cutting tools 63 laterally, so that the cutting tools 63 move along the curved direction of the curve-shaped wood beam 1 and cut the curve-shaped wood beam 1.

[51] In other words, the cutting tools 63 are rotated and revolved around the outer dr- cumference of the curve-shaped wood beam 1 so as to cut the curve-shaped wood beam 1. For keeping cutting the curve-shaped wood beam 1, the cutting tools 63 move forward or rearward and laterally, so that the cutting tools 63 move along the central axis of the curve-shaped wood beam 1. Therefore, the curve-shaped wood beam 1 can be cut into the curved shape having the circular cross-section.

[52] The diameter of the curve-shaped wood beam 1 is adjusted by moving the cutting tools 62 toward the central axis of the curve-shaped wood beam 1 using the diameter adjusting device 80.

[53] When the motor 83 of the diameter adjusting device 80 is rotated, the rotational force of the motor 83 is transmitted to the screw shaft 82 the rotational shafts 84 and 85, and the bevel gears, not shown, so that the moving plates 81 engaged with the screw nut move upward or rearward due to the rotation of the screw shaft 82. By doing this, since the cutting tools 62 move toward or away from the center of the curve- shaped wood beam 1 so as to cut the curve-shaped wood beam 1, the diameter of the curve-shaped wood beam 1 is adjusted.

[54] Since the moving degree of the laterally moving device 90 is indicated by the distance which the laterally moving device 90 has moved, an operator can adjust the moving distance of the laterally moving device 90. A laser generator is installed at the upper central portion of the moving device 50, so that the position of the cutting tools 63 is detected by the laser and indicated by the moving distance. In addition, the distance by which the diameter adjusting device 80 has moved is also displayed on a monitor, so that the operator can confirm the diameter of the curve-shaped wood beam 1.

[55] Since the moving device moves along the rails 11 of the frame 10, a receiver is installed to the inner rotational plate 73, and the rotation and movement of the cutting tools 63 and the forward and rearward and lateral movements of the moving device 50 can be controlled at the remote site by using a remote controller.

[56] When the curve-shaped wood beam 1 is cut off while the moving device 50 moves, the supports 40 are lowered by the air cylinders 42 so as to help the movement of the moving device 50 when the moving device moves, and the supports 40 are raised by the air cylinders 42 when the moving device has passed through.

[57] The supports 40 are fixed to the air cylinders 41 which are hinged to the frame 10 so that the height of the supports 40 can be adjusted by the air cylinders 41. The air cylinders 41 can be raised and lowered by the air cylinders 42 which are hinged to the frame 10.

[58] When the cutting tools 63 move to the position of the temporary fixing device 30 and the cutting of the curve-shaped wood beam 1 is finished, the motors 61 and 71 are stopped so as to stop the rotation and the revolution of the cutting tools 63, and the motor 53 is driven so as to return the moving device 50 to its original position after the motor 83 is driven so as to move the cutting tools 63 to the side of the curve-shaped wood beam 1.

[59] When the moving device 50 is returned to its original position, the curve-shaped wood beam 1 is separated from the wood cutting machine aooording to the present invention in reverse sequence for installing the curve-shaped wood beam 1 in the wood cutting machine, and thus the cutting is finished. When another curve-shaped wood beam 1 is placed in the wood cutting machine aooording to the present invention, the cutting process is performed as described above.

[60] In the case of forrring a standard wood beam from a wood beam 1 similar to the standard wood beam, if the moving distance of the cutting tools 63 and the distance between the cutting tools 63 in accordance with the moving distance of the cutting tools 63 are automatically set, the wood beam comprising the standard wood beam can be produced in accordance with the automatic procedure. [61] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those sMIled in the art will appreciate that various modi- fications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.