Abstract:
The present invention relates to a shear deformation device. To improve the productivity by solving the problem that the amount of shear deformation of a material is not uniform and sufficient due to the gap between the curved portion of the molding path and the lower parts of the material and omitting any additional process for removing irregularity and surface products on the surface of the material, there is provided a shear deformation device capable of scalping, characterized in that a scalping guide path which allows the surface of the material to be separated from the other portions of the material as the material is scalped at a predetermined thickness when passing through the curved portion during shear deformation is formed in the curved portion in communication with the molding path. In addition, there are provided additional constructions for effectively performing shear deformation by a small power by reducing the friction at the molding path excepting the curved portion. The present invention thusly constructed can be utilized for continuously and effectively mass-produce sheared materials.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shear deformation device for shearing materials, generally, metal materials, and more particularly, to a shear deformation device capable of shearing and at the same time scalping the materials at a predetermined thickness. 
     2. Description of the Background Art 
     The shear deformation process is a process of obtaining a sheared material by passing a material into a mold for shear deformation having a molding path at which a curved portion is formed, and allowing shear deformation of the material to occur at the curved portion. This process has the object of fabricating a material of high strength and high plasticity by improving the strength of the material and forming a texture having a certain direction. 
     The above-mentioned shear deformation processes includes equal channel angular pressing (ECAP), equal channel angular drawing (ECAD), continuous ECAP process, and so on. FIGS. 1 a ,  1   b  and  2  are views schematically illustrating shear deformation devices performing these shear deformation processes, respectively. As illustrated therein, the shear deformation devices are identical with one another in that each shear deformation device is constructed of molds  1 ,  2 ,  6 , and  7  provided with molding paths  3  and  8  having a curved portion shown in dotted line, but they are different from one another with respect to a means for applying power in order to passing materials  5  and  9  through the molds  3  and  8 . 
     Among these shear deformation processes, in case of equal channel angular pressing, only a sheared material of a limited length is obtained. Once the material is scalped, the next material can be provided only after extracting a punch  4  from the molds  1  and  2 , so it is impossible to continuously mass-producing sheared materials. In case of equal channel angular drawing, although it is possible to mass-produce sheared materials, it is difficult to practically use this process because it has little effect for shear deformation. For the continuous mass production of materials having an appropriate amount of shear deformation, a continuous shear deformation device illustrated in FIG. 2 which uses rotary guide apparatuses  10  and  11  in place of the punch  4  in order to continuously perform equal channel angular drawing is suitable. 
     However, in order to achieve shear deformation as the material implanted into the mold passes through the curved portion, much power is needed. Therefore, in case of using the rotary guide apparatuses  10  and  11 , it is general that irregularity is formed on the surface in contact with the material of the rotary guide apparatuses  10  and  11  in order to increase the friction between the material and the rotary guide apparatuses  10  and  11 . Subsequently, irregularity corresponding the above irregularity is formed on the surface of the material  9  having passed through the molds  6  and  7  for thereby making the surface rough. 
     In addition, even though the rotary guide apparatus is not used, there may be formed undesirable surface products on the surface of the material by material finishing processes prior to putting the material into the shear deformation device, that is, rolling and casting. 
     Meanwhile, in the conventional shear deformation device described above, there is a problem that the materials  5  and  9  cannot be tightly attached to the lower molds  2  and  7 , and thus the amount of shear deformation in the lower parts of the materials  5  and  9  becomes insufficient. FIG. 3 is a view illustrating the deformation of a material at a curved portion of a mold by simulation. By this, it is known that a board plank is not completely attached to a molding surface at the curved portion directed by an arrow, but is isolated therefrom. Accordingly, it is known that the amount of shear deformation in the lower portions of the material is not sufficient as compared to other portions, which is confirmed by an actual experiment performed by the inventors. That is, the scales indicated in a vertical direction on the sides prior to shear deformation of the material as shown in FIG. 4 a  are indicated as shown in FIG. 4 b  after passing through the continuous shear deformation device, which indicates that the amount of shear deformation in the lower portions of the material is smaller than that in other portions. 
     In addition, in the conventional discontinuous or continuous shear deformation devices described above, a curved portion is formed at the center of molding path  3  and  8  having the same widths, and thus the movement of the materials  5  and  9  is inhibited by the friction at the molding path excepting the curved portion at which shear deformation is actually occurred. Therefore, a considerable power plus the power required for shear deformation in the curved portion has to be additionally applied to the materials, which is ineffective. 
     In addition, there is another problem that the life span of the molds is not long because the abrasion occurred adjacent the curved portion which receives the largest friction force from the molds  3  and  8  is rapidly performed as compared to other portions. 
     SUMMARY OF THE INVENTION 
     Accordingly, the objects of the present invention disclosed to overcome the problems encountered in the conventional art will be described. 
     It is an object of the present invention to provide a shear deformation device capable of shearing material and at the same time removing irregularity or surface products formed on the surface of the material. 
     It is another object of the present invention to provide a continuous shear deformation device capable of obtaining an uniform and sufficient amount of shear deformation throughout the material by assuring contact between a lower part of the material and a curved portion in a molding path at which the material is sheared. 
     It is another object of the present invention to provide a continuous shear deformation device capable of press-fitting the material by small power as the friction between the portions of the molding path excepting the curved portion and the material is reduced. 
     It is another object of the present invention to provide a continuous shear deformation device capable of assuring a longer life span of the mold. 
     It is another object of the present invention to provide a continuous shear deformation device which can be compatibly used in response to materials of different thickness, that is, from thin-walled materials to thick-walled materials. 
     To achieve the above objects, there is provided a shear deformation device capable of scalping in accordance with the present invention which includes a mold having a molding path at which a curved portion is formed; and a material guiding apparatus for guiding a material to the molding path, wherein a scalping guide path which allows the surface of the material to be separated from the other portions of the material as the material is scalped at a predetermined thickness when passing through the curved portion during shear deformation is formed in the curved portion in communication with the molding path. 
     The above-mentioned shear deformation device can be a device performing a discontinuous equal channel angular pressing, a device performing a continuous shear deformation, or a device performing an equal channel angular drawing. In case of the discontinuous equal channel angular pressing, a punch corresponds to the guiding apparatus, and in case of the continuous shear deformation device, a rotary guide apparatus is used as the guiding apparatus. 
     In this case, since the thickness at which the material is scalped is determined according to the inner spacing of the scalping guide path, the scalping guide path can be formed to have a fixed inner spacing. However, in order to scalp the material at a desired thickness, it is preferable that a spacing adjusting apparatus for adjusting the inner spacing of the scalping guide path is additionally included. 
     As the rotary guide apparatus, a rotary roll contacting materials, or a belt transmission for moving materials by rotating a belt contacting the materials can be used. As the belt, belts of various shapes, such as a roof having a plurality of polyhedron blocks sequentially connected to the same and a belt of which the inside is chain-shaped, can be used. In addition, the rotary guide apparatus can be a combination of the rotary roll and the belt transmission. For example, the rotary guide apparatus can be constructed by installing a plurality of rotary rolls at one side and a belt transmission at the other side. Also, in case of using the belt transmission, it is possible to use a combination of belts of various shapes. 
     To reinforce the friction between the material and the rotary guide apparatus, it is preferable that irregularity is formed on the surface contacting the material of the rotary guide apparatus, that is, the surface of the rotary roll or the belt. This is achieved by coating the surface using an additional material of high friction coefficient, or by increasing the surface roughness by forming irregularity by mechanical processing. In addition, it is also possible to fabricate a portion directly contacting the material throughout the entire rotary guide apparatus by using a material of high friction coefficient. 
     The curved portion in the molding path can be formed at the center of the molding path as in the conventional art. Preferably, in order to reinforce the contact between the lower part of the material and the curved portion, the curved portion is constructed by collaboration between the rotary guide apparatus and the opening of the molding path, and the separation between the rotary guide apparatus and the mold constructs the scalping guide path. 
     And, it is preferable that a lateral guide for guiding and supporting the lateral parts of the material is installed at the rotary guide apparatus in order to prevent the material from being bilaterally moved while passing through the mold for the purpose of shear deformation. Such a lateral guide can be installed at one of the rotary guide apparatus and the mold, or at both of them. 
     In addition, it is preferable to construct the continuous shear deformation device by installing the rotary guide apparatus and the mold as one part of a continuous processing equipment, in order to perform shear deformation as one process step in a continuous process for processing the material by means of multiple process steps. For example, the material can be heated at a desired temperature, and then can be sheared. In this case, it is possible to connect the continuous shear deformation device to an apparatus for heating the material. In a case where a cast or rolled material is directly sheared, the continuous shear deformation device can be connected to a continuous casting apparatus or a rolling apparatus. In addition, the continuous shear deformation device can be connected to an apparatus for cooling, cutting, flattening, or winding the material extracted from the continuous shear deformation device. 
     With respect to this, the thickness of the material before passing through the rotary guide apparatus may be larger than the thickness of the material after passing through the same. For example, it can be assumed that the rotary guide apparatus is constructed by using a series of pairs of rotary rolls, the spacing between which being gradually reduced. In this case, it is possible to provide a compatible continuous shear deformation device to materials of different thickness, for example, thin-walled materials of a thickness less than 0.5 mm and thick-walled materials, irrespective of thickness of the materials, by rolling the materials corresponding to the clearance spacing of a material supply path having gradually reduced widths formed by the rotary guide apparatus, without any additional processing of the materials. 
     It is natural that the amount of shear deformation of the material is adjusted according to the angle of the curved portion. Moreover, it is also possible to additionally form one or more curved portions at the molding path of the mold besides the curved portion at the opening, so that the material is sheared more than two times while passing through the molding path. 
     Friction is most apparent in the vicinity of the curved portion in the mold at which shear deformation is occurred. Thus, in order to improve the abrasion resistance of the vicinity of the curved portion, it is possible to fabricate that portion using an ultralight material. At this time, the vicinity of the curved portion can be coated with the ultralight material, or it can be entirely made of the ultralight material. 
     In addition, some part including the curve portion in the mold, which is greatly abraded during shear deformation, can be constructed as a separate, replaceable component. 
     In order to reduce the power applied in the direction of the material by decreasing the friction between the mold and the material, it is preferable that a lubricant applicator is additionally included. 
     As another construction for reducing friction force, it is preferable that the widths of the molding path before the curved portion are formed to be larger than those of the molding path behind the curved portion, centering around the point spaced apart at a certain distance via the curved portion in the direction of the material, thereby reducing unnecessary friction between the material and the molding path. 
     Although the widths of the molding path before the curved portion are identical with those of the molding path behind the curved portion in general, it is also possible to design and fabricate a mold of which the widths of the molding path before and behind the curved portion are different from each other, so that the thickness of the material before shear deformation is different from that of the material after shear deformation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein: 
     FIG. 1 a  is a schematic view illustrating the device performing the conventional discontinuous equal channel angular pressing; 
     FIG. 1 b  is a schematic view illustrating the device performing the conventional equal channel angular drawing is performed; 
     FIG. 2 is a schematic view illustrating one example of a conventional discontinuous shear deformation device; 
     FIG. 3 is a view illustrating the deformation of a material occurred at a curved portion in a mold by means of simulation; 
     FIGS. 4 a  and  4   b  are photographs illustrating the change in scale on the lateral parts of a material when shear deformation is made using the conventional continuous shear deformation device, wherein FIG. 4 a  illustrates the change in scale prior to deformation, and FIG. 4 b  illustrates the change in scale after deformation; 
     FIGS. 5 a  and  5   b  are schematic views illustrating a discontinuous equal channel angular pressing shear deformation device and an equal channel angular drawing shear deformation device; 
     FIGS. 6 a  and  6   b  are schematic views illustrating a continuous shear deformation device in accordance with one embodiment of the present invention, wherein FIG. 6 a  illustrates a continuous shear deformation device using a pair of rotary rolls as a rotary guide apparatus, and FIG. 6 b  illustrates a continuous shear deformation device using a single rotary roll as a rotary guide apparatus; 
     FIG. 7 is an expansion view illustrating the curved portion which is shown in dotted line of FIGS. 6 a  and  6   b;    
     FIG. 8 is a photograph illustrating the shapes of chips removed from a material when the inner spacing of a scalping guide path is varied in a case where irregularity is formed on the surface contacting the material of a rotary guide apparatus in a continuous shear deformation device in accordance with one embodiment of the present invention; 
     FIG. 9 is a graph illustrating the amount of shear deformation according to the location of the material in the thickness direction when shear deformation of the material is made by differentiating the thickness of a scalped layer; 
     FIG. 10 is a photograph illustrating the change in scale on the lateral parts of a material by shear deformation in case of using a continuous shear deformation device in accordance with one embodiment of the present invention; 
     FIGS. 11 a  and  11   b  are schematic views illustrating a shear deformation device in accordance with another embodiment of the present invention, which includes a mold having two curved portions; and 
     FIGS. 12 a  and  12   b  are schematic views illustrating a shear deformation device in accordance with still another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     FIGS. 5 a  and  5   b  are schematic views illustrating the devices performing equal channel angular pressing and equal channel angular drawing in accordance with one embodiment of the present invention, and FIGS. 6 a  and  6   b  are schematic views illustrating continuous shear deformation devices each using two rotary rolls or a single rotary roll as a rotary guide apparatus in accordance with one embodiment of the present invention. As illustrated therein, the shear deformation device in accordance with the present invention includes molds  100 ,  101 ,  102 ,  106 ,  106 ′, and  107  having molding paths  103  and  109  at which a curved portion is formed, a material guiding apparatus for guiding materials  104  and  108  to the molding paths  103  and  109 . In the curved portion, scalping guide paths  105  and  112  allowing the surface of the material to be separated from the other portions of the material as the material is scalped at a predetermined thickness while passing through the curved portion during shear deformation, are formed in communication with the molding paths  103  and  109 . 
     In case of using the continuous shear deformation device, of course, the curved portion can be formed in the middle of the molding path. In addition, it is preferable that the curved portion is constructed by collaboration between rotary guide apparatuses  110  and  111  and the opening of the molding path  109  so that shear deformation is occurred in the location at which the material is inserted from the rotary guide apparatuses  110  and  111  to the molding path  109 , and the spacing between the rotary guide apparatuses  110  and  111  and the mold  107  constructs the scalping guide path  112 . By constructing the curved portion by collaboration between the rotary guide apparatus  110  and the opening of the molding path  109  as illustrated in FIGS. 5 a  and  5   b , rather than the middle of the molding path  8  as illustrated in FIG. 2, the following results can be obtained. Firstly, power is effectively transferred by increasing the contact area between the rotary guide apparatus  110  and the material  108 . Secondly, the power of the rotary guide apparatus  110  to press down the material  108  is directly applied to the material  108  until the material  108  reaches the curved portion and is sheared, thereby reinforcing the contact between the lower part of the material and the curved portion, and accordingly making it possible to obtain an uniform and sufficient shear deformation of the lower and upper parts of the material. 
     Although the scalping guide paths  105  and  112  of the shear deformation device in accordance with the present invention may have a fixed inner spacing, it is preferable that the scalping guide paths  105  and  112  are constructed so that the inner spacing is adjusted by a spacing adjusting apparatus for adjusting the inner spacing of the scalping guide paths  105  and  112 , in order to scalp the materials  104  and  108  at a desired thickness. As such a spacing adjusting apparatus, in case of the apparatus illustrated in FIGS. 5 a  and  5   b , an apparatus capable of fixing the mold  100  at the front part or the mold  102  at the lower part in a state of being moved bilaterally in the drawings is employed, or, in case of the apparatus as illustrated in FIGS. 6 a  and  6   b , an apparatus capable of fixing the same by bilaterally moving the rotary roll  110  is employed. 
     As the rotary guide apparatus, as illustrated in FIGS. 6 a  and  6   b , the rotary rolls  110  and  111  contacting the material  108 , or a belt transmission (not shown) for moving the material by rotating a belt contacting the material can be used. As the belt, belts of various shapes including a roof having a plurality of polyhedron blocks and a belt of which the inside is chain-shaped can be used. In addition, the rotary guide apparatus can be a combination of the rotary rolls and the belt transmission. For example, the rotary guide apparatus can be constructed by installing a plurality of rotary rolls at one side and a belt transmission at the other side. Also, in case of using the belt transmission, it is possible to use a combination of belts of various shapes. 
     To reinforce the friction between the material and the rotary guide apparatus, as in FIG. 7 illustrating an expansion view of the curved portion shown in dotted line of FIGS. 6 a  and  6   b , it is preferable that irregularity is formed on the surface contacting the material of the rotary guide apparatus, that is, the surfaces of the rotary rolls  110  and  111  or the surface of the belt. This irregularity is achieved by coating the surface with an additional material of high friction coefficient, or by increasing the surface roughness by forming irregularity by mechanical processing. In addition, it is also possible to fabricate a portion directly contacting the material throughout the entire rotary guide apparatus by using a material of high friction coefficient. 
     FIG. 8 is a photograph illustrating the shapes of chips removed from a material when the inner spacing of a scalping guide path in a case where irregularity is formed on the surface contacting the material of a rotary guide apparatus in a continuous shear deformation device in accordance with one embodiment of the present invention. Herein, the inner spacing is 0.15 mm at the utmost left side, the inner spacing at the center is 0.05 mm, and the inner spacing at the utmost right side is almost 0 mm. In case of the inner spacing of almost 0 mm, it can be shown that the irregularity of the surface of the material is solely removed and the thickness of a scalped layer is increased as the inner spacing is increased. 
     Meanwhile, FIG. 9 is a graph illustrating the amount of shear deformation according to the location of the material in the thickness direction when shear deformation of the material is made by differentiating the thickness of a scalped layer. Herein,  represents the result of simulation, □ represents the actual measured value in case of scalping the material at a thickness of 0.1 mm, and ♦ represents the actual measured value in case of scalping the material at a thickness of 0.2 mm. Herein, it can be known that the amount of shear deformation of the lower part of the material is increased as the thickness of the material that is scalped is increased. 
     In addition, FIG. 10 is a photograph illustrating the change in scale on the lateral parts of a material by shear deformation in case of using a continuous shear deformation device when the inner spacing of the scalping guide path is set to 0.15 mm in accordance with one embodiment of the present invention. Unlike FIG. 4 b , it can be known that sufficient shear deformation is also occurred at the lower part of the material. 
     As seen from the results of the experiment and the photographs, when the material is scalped during shear deformation by the device of the present invention, the irregularity and surface products formed on the surface of the material are removed for thereby facing the material. Besides, the layer to be scalped presses down the material while passing through the scalping guide path, being separated from the material, for thereby reinforcing the contact between the lower parts of the material and the curved portion, and appropriately performing shear deformation of the lower part of the material. 
     Meanwhile, although it is preferable that the scalped layer is guided and separated from the material through the scalping guide path between the rotary guide apparatus and the mold, it can be also attached to the surface contacting the material of the rotary guide apparatus by the power of the rotary guide apparatus to strongly press down the material. Thus, it is preferable that a scalped layer removing apparatus for removing the thusly attached scalped layer is additionally included. As such a scalping layer removing apparatus, a board plank  113  slightly contacting the portion not in contact with the material  108  of the rotary roll  110  of the rotary guide apparatus can be employed, as illustrated in FIGS. 6 a  and  6   b.    
     And, it is preferable that a lateral guide for guiding and supporting the lateral parts of the material is installed at the rotary guide apparatus in order to prevent the material from being bilaterally moved while passing through the mold for the purpose of shear deformation. Such a lateral guide can be installed at one of the rotary guide apparatus and the mold, or at both of them, or at both of them as a plate girder contacting the lateral parts of the material. 
     In addition, although the above-described continuous shear deformation device can be used exclusively in no relation with other devices, it is preferable to construct the continuous shear deformation device by installing the rotary guide apparatus and the mold as one part of a continuous processing equipment, in order to perform shear deformation as one process step in a continuous process for processing the material by means of multiple process steps. For example, the material can be heated at a desired temperature, and then can be sheared. In this case, it is possible to connect the continuous shear deformation device to an apparatus for heating the material. In a case where a cast or rolled material is directly sheared, the continuous shear deformation device can be connected to a continuous casting apparatus or a rolling apparatus. In addition, the continuous shear deformation device can be connected to an apparatus for cooling, cutting, flattening, or winding the material extracted from the continuous shear deformation device. 
     Usually, the thickness of the material before and after passing through the rotary guide apparatus are identical with each other. However, in the present invention, the thickness of the material before passing through the rotary guide apparatus may be smaller than the thickness of the material after passing through the same. For example, it can be assumed that the rotary guide apparatus is constructed by using a series of pairs of rotary rolls, the spacing between which being gradually reduced. In this case, it is possible to provide a compatible continuous shear deformation device to materials of different thickness, for example, thin-walled materials of a thickness less than 0.5 mm and thick-walled materials, irrespective of thickness of the materials, by rolling the materials corresponding to the clearance spacing of a material supply path having gradually reduced top and bottom widths formed by the rotary guide apparatus, without using any additional rolling apparatus. 
     In the present invention, the amount of shear deformation of the material can be adjusted according to the angle of the curved portion. For instance, as the angle of the curved portion is increased, the amount of shear deformation is increased. In order to increase the amount of shear deformation, it is also possible to additionally form one or more curved portions at the molding path of the mold besides the curved portion at the opening, so that the material is sheared more than two times while passing through the molding path, as illustrated in FIGS. 11 a  and  11   b.    
     In addition, to increase the amount of shear deformation of the material, the material having once passed through the continuous shear deformation device of the invention can be sheared while passing through the device at a desired number of times, or it is also possible that a desired number of continuous shear deformation devices are continuously installed, and then the material is sheared while passing through the devices. 
     Since friction is most apparent in the vicinity of the curved portion in the mold at which shear deformation of the material is occurred, the abrasion of the mold is most rapidly made. Thus, it is important to reduce the abrasion of that portion in order to increase the life span of the entire mold, so the vicinity of the curved portion is preferably made of ultralight material in order to improve the abrasion resistance of the vicinity the curved portion. At this time, the vicinity of the curved portion can be coated with the ultralight material, or it can be entirely made of the ultralight material. 
     In addition, one portion including the curve portion in the mold, which is greatly abraded during shear deformation, can be constructed as a separate, replaceable component, being separated from other portions of the mold. 
     In order to reduce the power applied in the direction of the material by decreasing the friction between the mold and the material, it is preferable that a lubricant applicator is additionally included. 
     The press-fit power, that is, the power of the rotary guide apparatus applied in the direction of the material corresponds to the power for shear deformation in the vicinity of the curved portion and the friction force between the mold and the material in the other portions. Thus, in order to perform shear deformation by a small press-fit power, it is important to decrease the friction force between the material and the mold excepting the curved portion. For this, it is preferable that a lubricant applicator is additionally included. 
     As another construction for reducing friction force, as illustrated in FIGS. 12 a  and  12   b , it is preferable that the widths of the molding path before the curved portion are formed to be larger than those of the molding path behind the curved portion, centering around the point spaced apart at a certain distance via the curved portion in the direction of the material, thereby reducing unnecessary friction between the material and the molding path. 
     Generally, the widths of the molding path before the curved portion are identical with those of the molding path behind the curved portion in order to make the thickness of the material before the curved portion identical with the thickness of the material in rear of the curved portion. However, if necessary, as illustrated in FIGS. 12 a  and  12   b , it is also possible to design and fabricate a mold of which the widths of the molding path before and behind the curved portion are different from each other, so that the thickness of the material before shear deformation is different from that of the material after shear deformation. Herein, the increase of the widths occurred when the material passes through the molding path is illustrated, and the decrease thereof is, of course, also possible. 
     Meanwhile, as illustrated in FIGS. 12 a  and  12   b , it is preferable that the scalping guide path is formed to have an inner spacing at a distance from the opening of the scalping guide path larger than the inner spacing at the opening. 
     In case of using the above-described shear deformation device capable of scalping, the material is sheared, and at the same time the irregularity and surface products formed on the surface of the material are removed, so that it is possible to omit an additional surface processing for thereby improving the productivity. 
     In addition, the scalped layer separated from the material attracts the lower parts of the material to be tightly attached to the curved portion, so that the contact between the lower parts of the material and the curved portion is reinforced for thereby obtaining an uniform and sufficient amount of shear deformation throughout the material. 
     And, by reducing the friction between the material and the mold at the molding path excepting the curved portion at which shear deformation is occurred, it is possible to effectively press-fit the material by a small power and to increase the life span of the mold. 
     In addition, in case of using the rotary guide apparatus in accordance with the present invention, the apparatus can be compatibly used corresponding to materials of different thickness, that is, thin-walled materials and thick-walled materials without any additional process. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.