Abstract:
A rotary cutter for a mower has a cord for cutting grass and the like by rotating itself; a reel for housing the cord and feeding the cord while intermittently rotating; a case for housing the reel; a cover for covering the case; and a pressing body protruding from the case. The pressing body is axially movable by being pressed, and intermittently rotating the reel. The reel and the pressing body are integrally constructed. Concave grooves for inserting the cord are provided in the reel in a radial direction and the cord is wound by fitting it to the concave grooves.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a rotary cutter for a mower used for mowing grass, lawn, and the like with a cord (principally made of nylon) extending in a radial direction of a case which is rotationally-driven by power of a motor or the like by way of an axis of rotation. 
     2. Description of the Related Art 
     As this type of rotary cutter, it is conventionally known a rotary cutter having a reel which houses a nylon cord, wherein when the cord is worn away, the cord is let out from the reel by pressing the cutter on the ground during rotation, by tapping the cutter or by running up the rotation of the cutter. As to this type of rotary cutter, when the cord housed in the reel was worn out, it was necessary to take out the reel by disassembling the rotary cutter, and wind a new cord, and then rearranging its components again. However, by such a way, it is very troublesome and inconvenient to carry out such procedures during mowing. Moreover, when the rotary cutter is disassembled and the reel is taken out, it has been feared that these components may be lost since associated components of the reel and other components are taken out at the same time. On this account, as the rotary cutter in which a cord replacement can be simplified when the cord is worn away, or, the rotary cutter in which the cord is replaceable without disassembling the rotary cutter itself, for example, a rotary cutter in which through-holes are formed in a part of a cylindrical body (a cord-winding part) of a reel, and the cord is inserted through the through-holes and wound onto the cylindrical body of the reel, is suggested (see Patent Documents 1 to 3). 
     Patent Document 1: Utility model registration No. 2,509,199 
     Patent Document 2: Japanese Patent Laid-Open No. 2005-124501 
     Patent Document 3: Published Japanese Translation of a PCT Application 2006-514837 
     In the case of the conventional rotary cutter as claimed in Patent documents 1 to 3, there is an advantage that the cord is replaceable without disassembling the rotary cutter and taking out the reel. However, for example, in the case of a rotary cutter described in Patent document 1, there are some drawbacks that it is necessary to provide a cord through-hole formed between an outer circumferential surface and an inner circumferential surface of a cylindrical body of a reel (a cord-winding part) of a reel, the cord through-hole being perpendicular to an axis of rotation without providing on the inner circumferential surface, so that top and bottom positions of its cord insertion opening and a guiding hole can be on the same horizontal plane. As a result, production/processing cannot be easily carried out in order to form its cord through-hole and the guiding hole. Therefore, the production cost of such a rotary cutter can be relatively high. Moreover, a rotary cutter described in Patent document 2 has a structure that a cord is sorted into upper and lower of two layers of a reel and is wound on the reel, and cord insertion holes are formed to sort the cord into up and down at a part of its partition. Therefore, such a rotary cutter has some drawbacks that the structure of the reel is relatively complicated; a lot of time and effort are needed for its production/processing; and the production cost of such a rotary cutter can be relatively high. In the case of the rotary cutter described in Patent document 3, the rotary cutter is comprised of two components of a cylindrical securement head having a reel at its shaft core, and a spool (a cord-winding part) mounted to the securement head. The spool, which is similar to that of the rotary cutter described in Patent document 2, has a structure that a cord is sorted into up and down and is wound thereon, and cord insertion holes are formed to sort the cord into up and down at a part of its partition through the spool and the securement head. 
     Therefore, the rotary cutter of Patent document 3 has some drawbacks that the structure of the reel is more complicated; much more time and effort are needed for its production/processing; and the production cost of such a rotary cutter can be higher. Further, in the case of the conventional rotary cutter as claimed in Patent documents 1-3, there is a common drawback that the insertion/conduction operation of the cord when the cord is wound on the reel requires time and effort. 
     The object of the present invention is to overcome the drawbacks of the above-described conventional rotary cutter, and to realize a rotary cutter in which its production/processing is simple and the production cost is inexpensive, having no possibility of losing associated components of a reel and other components when replacing a cord, and allowing the cord to be easily and quickly wound up. 
     SUMMARY OF THE INVENTION 
     According to a rotary cutter for a mower related to the present invention, a reel and a pressing body are integrally constructed, and a concave-grooves fitting method has been adopted instead of a conventional insertion method as a cord-winding mechanism to the reel. The rotary cutter for a mower is comprised of a cord for cutting grass and the like by rotating itself; a reel for housing the cord and feeding the cord while intermittently rotating; a case for housing the reel; a cover for covering the case; and a pressing body protruding from the case, being axially movable by being pressed, and intermittently rotating the reel. Further, the rotary cutter is characterized in that the reel and the pressing body are integrally constructed therein; concave grooves for inserting the cord are provided in the reel in a radial direction; and the cord is wound by fitting it to the concave grooves. 
     Moreover, in accordance with a preferred embodiment of the rotary cutter for a mower of this invention, at least one resilient element is axially mounted between the reel and the case; the reel and the pressing body are integrally constructed via/by way of the case; at least one resilient element is axially mounded between the case and the pressing body; and at least one resilient element is axially mounted, respectively between the reel and the cover and between the case and the pressing body. In addition, a spring or rubber is generally used as the resilient element. 
     In another embodiment of the rotary cutter for a mower of the present invention, instead of integrating the reel and the pressing body, the reel and the pressing body are separately constructed and each of them can be separately and axially moved. Further, the rotary cutter is characterized in that the reel and the pressing body are separated; the pressing body is mounted detachably on the case; at least two springs, one of which is a spring outwardly biasing the pressing body and the other is a spring biasing the reel toward the side of the case, are axially mounted in the rotary cutter; and the reel and the pressing body are separately and resiliently supported, respectively. Moreover, in accordance with a preferred embodiment of this rotary cutter for a mower, a retainer, which is integral with or separates from the pressing body, is provided between the pressing body and the case. In accordance with another preferred embodiment, concave grooves for inserting the cord are provided in the reel in a radial direction. 
     According to the above-mentioned two kinds of the rotary cutter for a mower of the present invention, the preferred aspects are that projections for preventing from uplifting the cord are provided on the inner wall of the concave grooves for inserting the cord, or, a shape of openings of the concave grooves for inserting the cord is formed into a hook/aduncate shape. 
     According to a rotary cutter for a mower related to the present invention, in which the reel and the pressing body are integrally constructed, there is no possibility of losing associated components of a reel and other components when replacing a cord, and a concave-grooves fitting method has been adopted instead of a conventional insertion method as a cord-winding mechanism to the reel, thus the cord is wound by inserting and fitting itself to the concave grooves for inserting the cord provided in the reel. As a result, it is possible to easily and quickly insert the cord and also quickly and positively wind up the cord to the reel. In accordance with a further aspect, structurally, there is a small number of items of components, its production/processing is simple, and the production cost is inexpensive. 
     According to a rotary cutter for a mower in which the reel and the pressing body are separately constructed, like the above-mentioned rotary cutter for a mower, there is no possibility of losing associated components of a reel and other components when replacing a cord, and structurally there is a small number of items of components, so its production/processing is simple, and the production cost is inexpensive. Furthermore, especially when replacing a cord, it is possible to wind up the cord to the reel easily, quickly and positively, since the pressing body can be rotated without moving up and down. Still further, like the above-mentioned rotary cutter for a mower, it is possible to insert the cord easily and quickly to the reel by the addition of an advantageous effect of concave grooves for inserting the cord. 
     According to the above-mentioned two kinds of the rotary cutter for a mower of the present invention, it is possible to prevent the cord from uplifting/deviating from the reel and to stably and positively wind up the cord when winding up the cord to the reel, by providing projections for preventing from deviating the cord on the inner wall of the concave grooves for inserting the cord, or, by forming a shape of openings of the concave grooves for inserting the cord into a hook/aduncate shape. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  to  FIG. 3  show the first embodiment of a rotary cutter for a mower of the present invention. 
         FIG. 1  is a top plane view of the first embodiment of the rotary cutter with a cover removed. 
         FIG. 2  is a vertical cross-sectional view of the rotary cutter covered with a cover. 
         FIG. 3  is a view of  FIG. 2  that is looked from a line A-A. 
         FIG. 4  is a vertical cross-sectional view of the second embodiment of the rotary cutter of the present invention, covered with a cover. 
         FIG. 5  is a vertical cross-sectional view of the third embodiment of the rotary cutter of the present invention, covered with a cover. 
         FIG. 6  is a vertical cross-sectional view of the fourth embodiment of the rotary cutter of the present invention, covered with a cover. 
         FIG. 7  is a vertical cross-sectional view of the fifth embodiment of the rotary cutter of the present invention, covered with a cover. 
         FIG. 8  is a vertical cross-sectional view of the sixth embodiment of the rotary cutter of the present invention, covered with a cover. 
         FIG. 9  and  FIG. 10  show the seventh embodiment of the rotary cutter of the present invention. 
         FIG. 9  is a top plane view of the rotary cutter with a cover removed. 
         FIG. 10  is a vertical cross-sectional view of the rotary cutter covered with a cover. 
         FIG. 11  is a schematic front view of a reel, showing an example of the structure of a part of a concave groove for inserting a cord of the rotary cutter of the present invention. 
         FIG. 12  is a schematic front view of a reel showing an example of a shape of an opening of a concave groove for inserting a cord. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is now made to the structure of the first embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 1  to  FIG. 3 . In the first embodiment of the rotary cutter for a mower, the cord is fed by bumping the rotary cutter (a pressing body). The rotary cutter has a structure that a reel  3  constructed integrally with a pressing body  4  which has a bottomed cylindrical shape, is mounted in the middle of a case  1  so that the pressing body  4  projects downwardly of the case  1 ; cord guides  8  are provided at a peripheral edge of the case  1 ; a cylindrical member  2 - 1  which projects in the central part of an inside of a cover  2  is detachably engaged to a circular recess  3 - 1  formed in the middle of the reel  3 ; and the cover  2  and the reel  3  are resiliently and mutually supported by a spring  7  which is located between the circular recess  3 - 1  and the cylindrical member  2 - 1 . 
     Moreover, concave grooves  5  for inserting the cord are formed in a diametrical direction through the center of the reel onto the top side of the reel  3  constructed integrally with the pressing body  4  having a bottomed cylindrical shape. The cord guides  8  are formed in the same straight line with this concave grooves  5  for inserting the cord and mounted to the case  1 . Each of the cord guides  8  has a concave groove  8 - 1  in the middle having the substantially same width as a concave groove  5  for inserting the cord. 
     The rotary cutter for a mower has a structure that the case  1  and the reel  3 , and the reel  3  and the cover  2  are respectively engaged by a concave-convex fitting, and the pressing body  4  is pushed inwardly by bumping the pressing body  4  against the ground. Accordingly, the engagement between the case  1  and the reel  3  is uncoupled and then reel  3  rotates to feed the cord  9  wound on the reel  3  is fed (paid out). At the same time, the reel  3  pushed inwardly engages with the cover  2  and then a rotation once stops. Then the reel  3  returns to an original position by resilience of the spring  7 , and then engages with the case  1  again and fixed. Reference number  10  stands for a nut member for connecting a drive rotary shaft (not shown) such as motors firmly fixed to the center of the cover  2 . 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 1  to  FIG. 3 , in replacing a cord when it is worn out, both the spring  7  and the cover  2  detachably engaged with the reel  3  constructed integrally with the pressing body  4  which has a bottomed cylindrical shape, are removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4  having a bottomed cylindrical shape, which is integrally constructed with the reel  3 , is gripped and the reel is rotated manually so that the cord  9  can be wound to the reel  3 . 
     In replacing a cord of the above-mentioned rotary cutter for a mower, there is little possibility of losing components of the rotary cutter, since, as described above, only the cover  2  and the spring  7  have to be removed without the need to remove other components. Moreover, it is possible to insert and wind up the cord to the reel easily and quickly since the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves for inserting the cord which are formed in the reel. 
     Next, reference is now made to the structure of the second embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 4 . The structure of this rotary cutter is almost the same as that of the rotary cutter shown in  FIG. 1 , except that it has a structure that the reel  3  and the pressing body  4  are separately formed and then connected with a screw with the case  1  sandwiched. In the second embodiment of the rotary cutter for a mower, a part of a concave portion  3 - 1  formed in a bottom face of the reel  3  is outwardly protruded into a through-hole  1 - 1  opened in the central part of the case  1 , and a bottomed cylindrical portion  4 - 1  of the pressing body  4  is engaged to this part of the concave portion  3 - 1 , axially slidably and rotatably by a concavo-convex fitting. Then, the reel  3  and the pressing body  4  are integrally constructed by connecting the connection/abutment of each of the central parts of the reel  3  and the pressing body  4  with a connecting screw  6 . In addition, the reason why the reel  3  and the pressing body  4  are separately formed and then integrally constructed with the screw, is that the case  1 , the reel  3  and the pressing body  4  do not separate into pieces when replacing the cord. 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 4 , in replacing a cord when it is worn out, like the rotary cutter of the above first embodiment, both the spring  7  and the cover  2  detachably engaged with the reel  3 , are removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4 , which is connected to the reel  3  with the screw, is gripped and the reel is rotated manually so that the cord  9  can be wound to the reel  3 . 
     Also, in replacing a cord of the above-mentioned rotary cutter for a mower, there is little possibility of losing components of the rotary cutter, since, as described above, only the cover  2  and the spring  7  have to be removed. Moreover, it is possible to insert and wind up the cord to the reel easily and quickly because the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves for inserting the cord which are formed in the reel. 
     Next, reference is now made to the structure of the third embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 5 . The structure of this rotary cutter is almost the same as that of the rotary cutter shown in  FIG. 4 , except that it has a structure that the position for attaching the spring  7 , which is to axially and resiliently support the pressing body  4 , is between the pressing body  4  and the case  1 . In the third embodiment of the rotary cutter for a mower, a part of a concave portion  3 - 1  formed in a bottom face of the reel  3  is outwardly protruded into a through-hole  1 - 1  opened in the central part of the case  1 , and a bottomed cylindrical portion  4 - 1  of the pressing body  4  is engaged to the part of the concave portion  3 - 1 , axially slidably and rotatably by a concavo-convex fitting. Then, the spring  7  is attached between an annular concave groove  1 - 2 , which projects at an outer circumferential portion of the through-hole  1 - 1  opened in the central part of the case  1 , and an annular concave groove ( 4 - 2 ) formed in the inside of the pressing body  4 , and the pressing body  4  is resiliently supported in the axial direction. Then, the reel  3  and the pressing body  4  are integrally constructed by connecting the connection/abutment of each of the central parts of the reel  3  and the pressing body  4  with a connecting screw  6 . 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 5 , in replacing a cord when it is worn out, like the rotary cutter of the above second embodiment, the cover  2  detachably engaged with the reel  3  is removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4 , which is connected to the reel  3  with the screw, is gripped and the reel is rotated manually so that the cord  9  can be wound to the reel  3 . 
     In replacing a cord of the above-mentioned rotary cutter for a mower having the constitution shown in  FIG. 5 , there is no possibility of losing any components of the rotary cutter, since only the cover  2  has to be removed without the need to remove the spring  7 . Moreover, as described above, it is possible to insert and wind up the cord to the reel easily and quickly since the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves for inserting the cord which are formed in the reel. 
     Next, reference is now made to the structure of the fourth embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 6 . The structure of this rotary cutter is almost the same as that of the rotary cutter shown in  FIG. 5 , except that it has a structure that the positions for attaching springs  7  to axially and resiliently support the pressing body  4 , are two places of between the cover  2  and the reel  3  and between the case  1  and the pressing body  4 . In the fourth embodiment of the rotary cutter for a mower, the cover  2  and the reel  3  are resiliently and mutually supported by one of the springs  7  which is located between the circular recess  3 - 2  formed in the middle of the reel  3  and the cylindrical member  2 - 1  which projects in the central part of an inside of the cover  2 . Then, a part of a concave portion  3 - 1  formed in a bottom face of the reel  3  is outwardly protruded into a through-hole  1 - 1  opened in the central part of the case  1 , and a bottomed cylindrical portion  4 - 1  of the pressing body  4  is engaged to the part of the concave portion  3 - 1 , axially slidably and rotatably by a concavo-convex fitting. The other spring  7  is attached between an annular concave groove  1 - 2 , which projects at an outer circumferential portion of the through-hole  1 - 1  opened in the central part of the case  1 , and an annular concave groove ( 4 - 2 ) formed in the inside of the pressing body  4 , and the pressing body  4  is resiliently supported in the axial direction. Then, the reel  3  and the pressing body  4  are integrally constructed by connecting the connection/abutment of each of the central parts of the reel  3  and the pressing body  4  with a connecting screw  6 . In addition, the reason why there are two places for attaching the springs  7  for axially and resiliently supporting the pressing body  4 , where are between the cover  2  and the reel  3  and between the case  1  and the pressing body  4 , is because load to rotate/turn the pressing body  4  can be reduced in winding up the cord. That is to say, load of the spring  7  becomes heavy in order to stabilize feeding of the cord, and thus it gets heavy to rotate/turn the pressing body  4 . Accordingly, two springs  7  are attached to the two places of top and bottom so that the load for winding up the cord can be reduced. 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 6 , in replacing a cord when it is worn out, the spring  7  and the cover  2  detachably engaged with the reel  3  are removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4 , which is connected to the reel  3  with the screw, is gripped and the reel is rotated manually so that the cord  9  can be wound to the reel  3 . 
     In replacing a cord of the above-mentioned rotary cutter for a mower having the constitution shown in  FIG. 6 , there is little possibility of losing components of the rotary cutter, since only the cover  2  and the spring  7  have to be removed. Moreover, as described above, it is possible to insert and wind up the cord to the reel easily and quickly not only because the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves for inserting the cord which are formed in the reel, but also because load to rotate the pressing body  4  can be reduced by the effect of two springs  7  of top and bottom. 
     Reference is now made to the structure of the fifth embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 7 . The structure of this rotary cutter is almost the same as that of the rotary cutter shown in  FIG. 1  to  FIG. 3 , except that it has a structure that the position for attaching the spring  7 , which is to axially and resiliently support the pressing body  4 , is between the reel  3  and the case  1 . The rotary cutter has a structure that a reel  3  constructed integrally with a pressing body  4  which has a bottomed cylindrical shape, is mounted in the middle of a case  1  so that the pressing body  4  projects downwardly of the case  1 ; and the case  1  and the reel  3  are resiliently and mutually supported by a spring  7  which is located between the reel  3  and the case  1 . 
     In replacing a cord when it is worn out, the cover  2  detachably engaged with the reel  3  constructed integrally with the pressing body  4  which has a bottomed cylindrical shape, is removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4  having a bottomed cylindrical shape, which is integrally constructed with the reel  3 , is gripped and the reel  3  is outwardly pulled out against the spring  7  and then rotated manually so that the cord  9  can be wound to the reel  3 . Moreover, feeding of the cord  9  can be achieved by manually gripping a portion of the pressing body  4  and outwardly pulling it out when the cord is worn out during operations. 
     In replacing a cord of the above-mentioned rotary cutter for a mower having the constitution shown in  FIG. 7 , there is no possibility of losing components of the rotary cutter, since, as described above, only the cover  2  has to be removed without the need to remove other components. Moreover, it is possible to insert and wind up the cord to the reel easily and quickly since the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves  5  for inserting the cord which are formed in the reel. 
     Reference is now made to the structure of the sixth embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 8 . The structure of this rotary cutter is almost the same as that of the rotary cutter shown in  FIG. 4 , except that it has a structure that the position for attaching the spring  7 , which is to axially and resiliently support the pressing body  4 , is between the reel  3  and the case  1 . In the sixth embodiment of the rotary cutter for a mower, a part of a concave portion  3 - 1  formed in a bottom face of the reel  3  is outwardly protruded into a through-hole  1 - 1  opened in the central part of the case  1 , and a bottomed cylindrical portion  4 - 1  of the pressing body  4  is engaged to this part of the concave portion  3 - 1 , axially slidably and rotatably by a concavo-convex fitting. In such a condition, the reel  3  and the pressing body  4  are integrally constructed by connecting the connection/abutment of each of the central parts of the reel  3  and the pressing body  4  with a connecting screw  6 , and the pressing body  4  constructed integrally with the reel  3  is resiliently supported by attaching the spring  7  between the case  1  and the reel  3 . 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 8 , in replacing a cord when it is worn out, like the rotary cutter of the above first embodiment, the cover  2  detachably engaged with the reel  3  is removed, and then a portion which is located in the central part of a long and new cord having a desired length, is fitted and placed to the concave grooves  5  for inserting a cord formed to the empty reel  3  which is engaged with the case  1  and to the concave grooves  8 - 1  on the cord guide  8  formed in the same straight line with this concave grooves  5  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides only at a suitable length. In such conditions, a portion of the pressing body  4 , which is connected to the reel  3  with the screw, is gripped and the reel is rotated manually so that the cord  9  can be wound to the reel  3 . 
     In replacing a cord of the above-mentioned rotary cutter for a mower having the constitution shown in  FIG. 8 , there is no possibility of losing components of the rotary cutter, since, as described above, only the cover  2  has to be removed without the need to separately remove the case  1 , the reel  3 , the pressing body  4  and the spring  7 . Moreover, it is possible to insert and wind up the cord to the reel easily and quickly since the cord can be wound with the reel  3  fixed to the case  1  after inserting and fitting a new cord to concave grooves  5  for inserting the cord which are formed in the reel  3 . 
     Reference is now made to the structure of the seventh embodiment of the rotary cutter for a mower of the present invention shown in  FIG. 9  to  FIG. 10 . In the seventh embodiment of the rotary cutter for a mower, the cord is fed by bumping the rotary cutter (a pressing body  4 ). This rotary cutter has a structure that, a part of a concave portion  13 - 1  formed in a bottom face of a reel  13  is engaged to a part of a concave portion  11 - 1  formed in the inner central part of a case  11 , axially slidably and rotatably by a concavo-convex fitting; then, a circular pressing body  14  being concave in cross-section has a structure that a cylindrical retainer  16  is outwardly engaged to a coupling cylindrical portion  14 - 1  having a screw hole  14 - 1   a  which is provided in an extended condition in an inner central part of the pressing body  14 , and the coupling cylindrical portion  14 - 1  with the retainer  16  of the pressing body  14  being concave in cross-section is rotatably penetrated through a through hole  11 - 1   a  provided in the central part of the concave portion  11 - 1  of the case  11  and a through hole  13 - 1   a  provided in the central part of the concave portion  13 - 1  of the reel  13 ; an engaging projection  13 - 1   b , which is downwardly projected on the circumference of the central part of the bottom face of the concave portion  13 - 1  formed on the bottom face of the reel  13 , is engaged with an engaging slot  16 - 2  formed in the retainer  16 ; the pressing body  14  is fixed to the case  11  by tightening the retainer  16  and the coupling cylindrical portion  14 - 1  having the screw hole  14 - 1   a  with a coupling screw  15  through/via a washer  17 , in the state that a coupling flange  16 - 1  horizontally provided in an extended condition on the circumference of the lower part of the retainer  16  is sandwiched between the bottom face of the concave portion  11 - 1  of the case  11  and the bottom face of the concave portion  13 - 1  of the reel  13 ; the pressing body  14  is axially movable by a spring  18   a  which is located between the pressing body  14  and the case  11 ; and the reel  13  is axially movable and resiliently supported by a spring  18   b  which is located between the bottom face of the concave portion  13 - 1  of the reel  13  and the washer  17 . In addition, as to the retainer  16  located between the pressing body  14  and the case  11 , a retainer constructed separately from the pressing body  14  is used here, however, the retainer can also be constructed integrally with the pressing body  14 . 
     Moreover, concave grooves  13 - 2  for inserting a cord are formed in a diametrical direction through the center of the reel onto the top side of the reel  13 . The cord guides  19  are provided at a peripheral edge of the main body comprised of the case  11  and a cover  12  in the same straight line with this concave grooves  13 - 2  for inserting the cord. In addition, each of the cord guides  19  can be a ring-shaped one, and also have a concave groove in the middle having the same width as a concave groove  13 - 2  for inserting the cord (not shown). Reference number  21  stands for a nut member for connecting a drive rotary shaft (not shown) such as motors firmly fixed to the center of the cover  12 . 
     The above rotary cutter for a mower has a structure that the case  11  and the reel  13 , and the reel  13  and the cover  12  are respectively engaged by a concave-convex fitting, and the pressing body  14  is pushed inwardly by bumping the pressing body  14  against the ground. Accordingly, the engagement (mesh) between the case  11  and the reel  13  is uncoupled and then reel  13  rotates to feed a cord  20  wound on the reel  13  is fed (paid out). At the same time, the reel  13  pushed inwardly engages with the cover  12  and then a rotation once stops. Then the reel  13  returns to an original position by resilience of the spring  18   a , and then engages with the case  11  again and fixed. 
     According to the rotary cutter for a mower having constitutions shown in the above-mentioned  FIG. 9  to  FIG. 10 , in replacing the cord  20  when it is worn out, the cover  12  is removed and then a portion which is located in the central part of a long and new cord  20  having a desired length, is fitted and placed to the concave grooves  13 - 2  for inserting the cord formed to the empty reel  13  which is engaged with the case  11  and to the cord guide  19  formed in the same straight line with this concave grooves  13 - 2  for inserting the cord from the top of these grooves, while making both ends of the cord respectively stick out from the cord guides  19  only at a suitable length. In such conditions, a portion of the pressing body  14  constructed separately from the reel  13 , is gripped and the reel  13  is rotated manually so that the cord  20  can be wound to the reel  13 . In winding up this cord, the reel  13  moves up and down along the circumference of the retainer  16  through/via the spring  18   b , by an engagement mechanism of a concave-convex fitting between the case  11  and the reel  13 , and the reel  13  and the cover  12 . However, it is possible to wind up the cord  20  easily and quickly since the pressing body  14  constructed separately from the reel  13  can be rotated without moving up and down. Moreover, it is possible to insert and wind up the cord  20  to the reel  13  easily and quickly since the cord can be wound with the reel  13  fixed to the case  1  after inserting and fitting a new cord to concave grooves  13 - 2  for inserting the cord which are formed in the reel. Furthermore, in replacing a cord, there is little possibility of losing components of the rotary cutter, since, as described above, only the cover  12  has to be removed without the need to remove other components. 
     Moreover, as for the concave grooves  5 ,  13 - 2  for inserting a cord in the rotary cutter for a mower shown in  FIG. 1  to  FIG. 10 , it is possible to stably, quickly and positively wind up the cord when winding up the cord by, for example, providing projections  5 - 1  for preventing from uplifting the cord on the inner wall of the concave grooves  5  for inserting the cord as shown in  FIG. 11 , or, by forming a shape of openings of the concave grooves  5  for inserting the cord into a hook/aduncate shape  5 - 2  as shown in  FIG. 12 . 
     In addition, for cord guides  8  in a rotary cutter for a mower shown in  FIG. 1  to  FIG. 8 , a cord guide having a grooved shape is shown, such as the one having a concave groove  8 - 1  which has the substantially same width as a concave groove  5  for inserting the cord. However, the cord guide is not limited to be in the shape of a grooved shape, but can also be in the shape of a tubular shape, as shown in  FIG. 9  and  FIG. 10 . 
     According to a rotary cutter for a mower related to the present invention, in which the reel and the pressing body are integrally constructed, there is no possibility of losing associated components of a reel and other components when replacing a cord, and a concave-grooves fitting method has been adopted instead of a conventional insertion method as a cord-winding mechanism to the reel, thus the cord is wound by inserting and fitting itself to the concave grooves for inserting the cord provided in the reel. As a result, it is possible to easily and quickly insert the cord and also quickly and positively wind up the cord to the reel. In accordance with a further aspect, structurally, there is a small number of items of components, its production/processing is simple, and the production cost is inexpensive. Furthermore, it is possible to prevent the cord from uplifting/deviating from the reel and to stably and positively wind up the cord when winding up the cord to the reel, by providing projections for preventing from deviating the cord on the inner wall of the concave grooves for inserting the cord, or, by forming a shape of openings of the concave grooves for inserting the cord into a hook/aduncate shape. 
     According to a rotary cutter for a mower in which the reel and the pressing body are separately constructed, like the above-mentioned rotary cutter for a mower, there is no possibility of losing associated components of a reel and other components when replacing a cord, and structurally there is a small number of items of components, so its production/processing is simple, and the production cost is inexpensive. Furthermore, especially when replacing a cord, it is possible to wind up the cord to the reel easily, quickly and positively, since the pressing body can be rotated without moving up and down. Still further, like the above-mentioned rotary cutter for a mower, it is possible to insert the cord easily and quickly to the reel by the addition of an advantageous effect of concave grooves for inserting the cord. 
     Hence, the rotary cutter for a mower claimed in the present invention has a tremendous practical application as a bush cutter for cutting lawn or weed.