Patent Document

FIELD OF THE INVENTION 
     The present invention relates to a slide guide for a press. A slide guide is a device that guides a slide so that it can be raised and lowered in a precise manner. 
     BACKGROUND OF THE INVENTION 
     A conventional press includes a copper alloy liner adhered to a slide and an iron gib installed on the frame of the press. The slide is guided relative to the frame, while the liner and the gib slide against each other. 
     Lubricating oil is applied between the sliding surfaces of the liner and the gib. A clearance of approximately 0.05 mm is maintained between the liner and the gib. Uneven loading and the like may produce a line of contact between the liner and the gib, which may result in inadequate clearance and breaks in the oil film. This can damage the sliding surface and the main motor of the press. 
     It is particularly difficult to maintain proper clearance during precision pressing operations. Typical presses, such as two-point and four-point presses, handle larger slides by increasing the number of pressure-application points for applying eccentric loads. However, the dimensions of the crown, columns, bed, crank shaft, connecting rod, and the like must be precise in order to maintain levelness between the lower surface of the slide and the upper surface of the bolster. These components cannot be produced easily since they require a high level of precision. When the dimensions of these components are not sufficiently precise, a line of contact may form between the liner and the gib during operation under large eccentric loads. 
     Japanese patent application number 2000-193782 discloses a press in which a block with a spherical surface and a gib are interposed by a liner. The block and the gib can slide relative to each other via a V-shaped sliding surface. However, the V-shaped surfaces of the spherical-surface block and the gib are not easy to manufacture. The V-shaped surface on the spherical-surface block may spread apart under a large load, resulting in poor contact between the V-shaped surfaces. Japanese patent application number 2000-355350 discloses a device that is not affected by this problem. 
     SUMMARY OF THE INVENTION 
     The slide guide device of the present invention includes spherical surfaces that provide uniform, secure contact at the sliding surface and prevents uneven contact at the sliding surface. 
     A spherical surface body serves as a gib structure and is provided with a holder or a cap to cover the spherical surface body. The slide guide device comprises a gib, a spherical surface body, and a holder. The gib is disposed on a frame on the press. The spherical surface body is formed with a convex spherical surface and a flat surface that can slide against the gib. The holder is secured to a slide of the press and is formed with a concave spherical surface section that engages the convex spherical surface section of the spherical surface body. A pair of spherical surface bodies can be disposed on the slide, and the gibs corresponding to the spherical surface bodies can be positioned at an optimal angle which can be convex or concave. The holder can fit into a depression on the slide. 
     Alternatively, the slide guide device can comprise a gib, a cap, and a spherical surface body. The gib is disposed on a frame of the press. The cap is formed with a concave spherical surface and a flat surface that can slide against the gib. The spherical surface body is secured to the slide on the press and is formed with a convex spherical surface section which engages the concave spherical surface section of the cap. A pair of spherical surface bodies can be disposed on the slide of the press, and the gibs corresponding to the spherical surface bodies can be positioned at an optimal angle which can be convex or concave. The holder can fit into a depression on the slide. 
     The objects, features, and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a press according to the present invention. 
         FIG. 2  is a lateral cross-section drawing of a gib in an embodiment of the present invention. 
         FIG. 3  is a lateral cross-section drawing of a gib in an alternate embodiment of the present invention. 
         FIG. 4  is a detail drawing of a gib of  FIG. 3 . 
         FIG. 5  is a lateral cross-section drawing of a gib in an alternate embodiment of the present invention. 
         FIG. 6  is a detail drawing of a gib of  FIG. 5 . 
         FIG. 7  is a lateral cross-section drawing of a gib in an alternate embodiment of the present invention. 
         FIG. 8  is a lateral cross-section drawing of a gib in an alternate embodiment of the present invention. 
         FIG. 9  is a detail drawing of a gib of  FIG. 8 . 
         FIG. 10  is a lateral cross-section drawing of a gib in an alternate embodiment of the present invention. 
         FIG. 11  is a detail drawing of a gib of  FIG. 10 . 
     
    
    
     LIST OF DESIGNATORS 
       1 : frame;  2 : slide;  3 : bolster;  4 : connecting rod;  5 : gib;  6 : gib;  6   a : projection;  6   b : engagement section;  7 : spherical surface body;  8 : spherical surface body;  9 : spherical surface body;  10 : spherical surface body;  11 : liner;  12 : wedge;  13 : gib holder;  13   a : engagement section;  14 : gib holder;  14   a : engagement section;  15 : hollow screw;  16 : bolt;  17 : bolt;  18 : cap;  19 : stay;  23 : shoe;  24 : gib;  24   a : projection;  25 : gib;  26 : bolt;  27 : holder;  28 : bolt;  31 : bolt;  32 : bolt;  33 : gib 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A press according to the present invention is shown in  FIGS. 1 and 2 . A bolster  3  is secured to the base of a frame  1 , and a slide  2  faces the bolster  3 . A crank mechanism comprises a crank shaft (not shown) and a connecting rod  4 . The connecting rod  4  is connected to the slide  2 , and the crank mechanism raises and lowers the slide  2 . 
     A stay  19  extends between the left and right columns of the frame  1 . The stay  19  restricts the displacement of the left and right columns and is located approximately at the midpoint of the vertical motion of the slide  2 . The stay  19  prevents deformation and torsion of the frame  1 . However, the stay  19  may be removed. 
     Gibs  5 ,  6  are disposed on the frame  1 , and spherical surface bodies  7 ,  8 ,  9 ,  10  are disposed on the slide  2 . The slide  2  is guided by the spherical surface bodies  7 ,  8 ,  9 ,  10  while the slide  2  is raised and lowered along the gibs  5 ,  6 . 
     A cross-sectional view of the press through gibs  5 ,  6  is shown in  FIG. 2 . The drawing is rotated 90° counter-clockwise to facilitate the presentation. Gib holders  13 ,  14  are secured to the frame  1  using bolts or the like. Engagement units  13   a,    14   a  formed on gib holders  13 ,  14  fit into grooves on the frame  1 . 
     A hollow screw  15  with threads on the outer perimeter screws into a screw hole of gib holder  14 . A bolt  16  secures the hollow screw  15  to gib holder  14 . The end of bolt  16  is inserted into the hollow screw  15  and screws into the end of a wedge  12 . The end of the hollow screw  15  pushes the wedge  12  and fixes the position of the wedge  12 . The hollow screw  15  and bolt  16  align the wedge  12  relative to gib holder  14 . 
     Gib  5  is aligned likewise relative to gib holder  13 . Furthermore, the wedge  12  is tapered so that gib  5  can be moved forward and backward relative to the slide  2 . Gib  5  and the wedge  12  are secured to the frame  1  with bolt  17  after gib  5  and the wedge  12  are aligned. 
     A sheet-like liner  11  is secured to gib  5  with a screw and is adhesed lengthwise along gib  5 . However, the liner  11  can be removed so that spherical surface bodies  7 ,  9  slide directly against gibs  5 ,  6 . 
     Spherical surface body  7  forms a section of a sphere and is disposed on the slide  2 . The height of spherical surface body  7  is approximately 30% of the corresponding sphere. Spherical surface body  7  includes a convex spherical surface section and a flat section that can slide against the liner  11 . A holder  27  is inserted between the slide  2  and spherical surface body  7 . A bolt  26  secures the holder  27  to the slide  2 , and the holder  27  can fit into a depression on the slide  2 . The holder  27  includes a concave spherical surface section that engages with the convex spherical surface section of spherical surface body  7 . Spherical surface body  7  can pivot while engaged with the holder  27 . 
     The position of gib  5  can be adjusted, but the position of gib  6  is fixed. Gib  6  does not need to be adjustable since gib  5  can be adjusted. An engagement section  6   b  of gib  6  fits into a groove formed in the frame  1 , and bolt  17  secures gib  6  to the frame  1 . A spherical surface body  9  is disposed on the slide  2  in a similar manner to spherical surface body  7 . Spherical surface body  9  and the structure to which it is attached is formed similarly to spherical surface body  7  and its corresponding structure. 
     Spherical surface body  7  is engaged with the holder  27 . The holder  27  fits into the depression in the slide  2  and is secured to the slide  2  with bolt  26 . Then, gib  6  is secured to the frame  1 . Next, the wedge  12  and gib  5  are assembled. The hollow screw  15  and bolt  16  align the wedge  12  and gib  5  while preserving the contact between the liner  11  and a cap  18 . Bolt  17  secures the wedge  12  and gib  5  to the frame  1 . 
     A shoe  23  is adhesed to the slide  2 . The shoe  23  contacts and slides against gib holders  13 ,  14  and the guide surface of gib  6 . Spherical surface bodies  7 ,  9  can restrict the left and right movement of the slide  2 , and the shoe  23  can restrict the front and back movement, as shown in  FIG. 2 . 
       FIGS. 3 and 4  show an alternate embodiment of the present invention.  FIG. 3  is a lateral cross-sectional view of  FIG. 1  along gibs  5 ,  6 . The drawing is rotated 90° counter-clockwise to facilitate the presentation.  FIG. 4  is a detailed view of the upper gib section of  FIG. 3 . 
     Gib holders  13 ,  14  are secured to the frame  1  using bolts (not shown). Engagement units  13   a,    14   a  formed on gib holders  13 ,  14  fit into grooves on the frame  1 . 
     The hollow screw  15  with threads on the outer perimeter screws into a screw hole of gib holder  13 . Bolt  16  secures the hollow screw  15  to gib holder  13 . The end of bolt  16  is inserted into the hollow screw  15  and screws into the end of the wedge  12 . The end of the hollow screw  15  pushes the wedge  12 , thereby fixing the position of the wedge  12 . The hollow screw  15  and bolt  16  align the wedge  12  relative to gib holder  13 . 
     Gib  5  is aligned relative to gib holder  14  in a similar manner. Furthermore, the wedge  12  is tapered so that gib  5  can be moved forward and backward relative to the slide  2 . Gib  5  and the wedge  12  are secured to the frame  1  with bolt  17  after gib  5  and the wedge  12  are aligned. 
     The sheet-like liner  11  is secured to gib  5  with a screw and is adhesed lengthwise along gib  5 . However, the liner  11  can be removed so that spherical surface bodies  7 ,  9  slide directly against gibs  5 ,  6 . 
     Spherical surface body  7  forms a section of a sphere and is disposed on the slide  2 . The height of spherical surface body  7  is approximately 30% of the corresponding sphere. Spherical surface body  7  includes a convex spherical surface section and a flat section that can slide against the liner  11 . The holder  27  is inserted between the slide  2  and spherical surface body  7 . Bolt  26  secures the holder  27  to the slide  2 , and the holder  27  can fit into a depression on the slide  2 . The holder  27  includes a concave spherical surface section that engages with the convex spherical surface section of spherical surface body  7 . Spherical surface body  7  can pivot while engaged with the holder  27 . 
     The position of gib  5  can be adjusted, but the position of gib  6  is fixed. Gib  6  does not need to be adjustable since gib  5  can be adjusted. Gib  6  abuts an abutting section  6   a  formed on the frame  1  and is secured to the frame  1  by bolt  17 . 
     Spherical surface bodies  7 ,  9  are engaged with the holder  27 . The holder  27  fits into the depression in the slide  2  and is secured to the slide  2  with bolt  26 . Then, gib  6  is secured to the frame  1 . Next, the wedge  12  and gib  5  are assembled. The hollow screw  15  and bolt  16  align the wedge  12  and gib  5  while preserving the contact between the liners  11  and the spherical surface bodies  7 ,  9 . Bolt  17  secures the wedge  12  and gib  5  to the frame  1 . 
     The liners  11  are adhesed to gibs  5 ,  6 . The surfaces of the liners  11  are positioned to form an angle α, as shown in  FIG. 4 . The holder  27  transfers pressure from the slide  2  to the contact surfaces of the liners  11  where the liners  11  contact the flat sections of the spherical surface bodies  7 ,  9 . 
     The force applied to the contact surfaces can be considered as separate lateral and longitudinal forces that restrict the slide  2  since the contact surfaces are inclined. Therefore, the slide  2  is restricted both laterally and longitudinally by the gibs  5 ,  6 . The angle α is approximately 120° and is determined from the status of the eccentric load of the press. The lateral projected area is larger than the longitudinal projected area when the lateral eccentric load is greater than the longitudinal eccentric load. When α is 120°, the projected area ratio between the lateral projected area and the longitudinal projected area is √3:1, i.e., approximately 1.7:1. 
       FIGS. 5 and 6  show an alternate embodiment of the present invention. Spherical surface bodies  7 ,  9  are disposed on the slide  2  as described above. 
     Gibs  24 ,  25  and gib holder  14  are disposed on the frame  1 . A projection  24   a  is formed on the frame  1  and abuts gib  24 . A bolt  31  secures gib  24  to the frame  1 . The structure of gib holder  14  is the same as that of the above-described embodiments. Gib holder  14  can be used to adjust the position of gib  25  which can be secured to the frame  1  with bolt  32 . 
       FIG. 5  shows the liners  11 , which serve as a pair of guide surfaces, positioned on the sliding surfaces so that they face toward the center of the slide  2 . However, the sliding surfaces of the embodiment of the present invention shown in  FIG. 3  face away from the slide, thereby allowing the structure to adjust to the effects of increasing temperature or the like in the slide  2 . The slide  2  expands relative to gibs  24 ,  25  when the temperature of the slide  2  increases. However, the deformation of the slide  2  can be accommodated more easily when the sliding surfaces face away from the center of the slide  2  as in  FIG. 3 . Therefore, the liners  11  can be eliminated in the embodiment of the present invention shown in  FIG. 3  so that spherical surface bodies  7 ,  9  and gibs  24 ,  25  slide directly against each other. 
       FIG. 7  shows an alternate embodiment of the present invention that is similar to the embodiment shown in  FIG. 2 . However, spherical surface bodies  7 ,  9  are installed differently in these two embodiments. 
       FIG. 7  is a lateral cross-sectional view of  FIG. 1  along gibs  5 ,  6 . The drawing is rotated 90° counter-clockwise to facilitate the presentation. Gib holders  13 ,  14  are secured to the frame  1  with bolts (not shown). The engagement units  13   a,    14   a  formed on gib holders  13 ,  14  are fitted to grooves on the frame  1 . 
     The hollow screw  15  is screwed into gib holder  14  and is secured by bolt  16 . The end of bolt  16  is inserted into the hollow screw  15  and screws into the end of the wedge  12 . The end of the hollow screw  15  pushes the wedge  12 , thereby fixing the position of the wedge  12 . The hollow screw  15  and bolt  16  align the wedge  12  relative to gib holder  14 . 
     Gib  5  is aligned relative to gib holder  13  in a similar manner. Furthermore, the wedge  12  is tapered so that gib  5  can be moved forward and backward relative to the slide  2 . The wedge  12  and gib  5  are aligned and then secured to the frame  1  with bolt  17 . 
     A screw secures the liner  11  to gib  5 . The sheet-like liner  11  is adhesed lengthwise along gib  5 . However, the liner  11  can be eliminated, and then, the cap  18  can slide directly against gibs  5 ,  6 . 
     Bolt  26  secures spherical surface body  7  to the slide  2 . Spherical surface body  7  fits into a depression formed on the slide  2 . The cap  18  includes a concave spherical surface section and is inserted between spherical surface body  7  and the liner  11 . The concave spherical surface section of the cap  18  engages with the convex spherical surface section of spherical surface body  7  so that the cap  18  can pivot within the spherical surface of spherical surface body  7 . Additionally, the cap  18  includes a flat section, and this flat section and the liner  11  can slide against each other. 
     The position of gib  5  can be adjusted, but the position of gib  6  is fixed. Gib  6  does not need to be adjustable since gib  5  can be adjusted. The engagement section  6   b  of gib  6  fits into a groove formed in the frame  1 , and bolt  17  secures gib  6  to the frame  1 . 
     The caps  18  engage with the spherical surface bodies  7 ,  9 . Spherical surface bodies  7 ,  9  fit into depressions in the slide  2  and are secured to the slide  2  with bolt  26 . Then, gib  6  is secured to the frame  1 . Next, the wedge  12  and gib  5  are installed. The positioning of gib  5  is adjusted with the hollow screw  15 , bolt  16 , and the wedge  12  while preserving the contact between the liner  11  and the cap  18 . Bolt  17  secures the wedge  12  and gib  5  to the frame  1 . 
     The shoe  23  is adhesed to the slide  2 . The shoe  23  contacts and slides against gib holders  13 ,  14  and the guide surface of gib  6 . The caps  18  restrict the left and right movement of the slide  2 , and the shoe  23  restricts the forward and backward movement of the slide  2 . 
       FIGS. 8 and 9  show an embodiment of the present invention that is similar to the embodiment shown in  FIGS. 3 and 4 . However, the spherical surface bodies  7 ,  9  are installed differently in the two embodiments. 
       FIG. 8  is a lateral cross-sectional view of  FIG. 1  along gibs  5 ,  6 . The drawing is rotated 90° counter-clockwise to facilitate the presentation.  FIG. 9  is a detailed view of the upper gib section of  FIG. 8 . 
     Gib holders  13 ,  14  are secured to the frame  1  with bolts (not shown). The engagement units  13   a,    14   a  formed on gib holders  13 ,  14  are fitted into grooves on the frame  1 . 
     The hollow screw  15  screws into gib holder  13  and is secured by bolt  16 . The end of bolt  16  is inserted into the hollow screw  15  and screws into the end of the wedge  12 . The end of the hollow screw  15  pushes the wedge  12 , thereby fixing the position of the wedge  12 . The hollow screw  15  and bolt  16  align the wedge  12  relative to gib holder  13 . 
     Gib  5  is aligned relative to gib holder  14  in a similar manner. Furthermore, the wedge  12  is tapered so that gib  5  can be moved forward and backward relative to the slide  2 . Gib  5  and the wedge  12  are secured to the frame  1  with the bolt  17  after gib  5  and the wedge  12  are aligned. 
     The sheet-like liner  11  is secured to gib  5  with a screw and is adhesed lengthwise along gib  5 . However, the liner  11  can be removed so that spherical surface bodies  7 ,  9  slide directly against gibs  5 ,  6 . 
     Bolt  26  secures spherical surface body  7  to the slide  2 . Spherical surface body  7  can fit into the depression on the slide  2 . The cap  18  has a concave spherical surface section and is inserted between spherical surface body  7  and the liner  11 . The concave spherical surface section of the cap  18  engages with the convex spherical surface section of spherical surface body  7  so that the cap  18  can pivot along the spherical surface of spherical surface body  7 . The cap  18  also includes a flat section, and this flat section and the liner  11  can slide against each other. 
     The position of gib  5  can be adjusted, but the position of gib  6  is fixed. Gib  6  does not need to be adjustable since gib  5  can be adjusted. Gib  6  abuts an abutting section  6   a  formed on the frame  1  and is secured to the frame  1  by bolt  17 . 
     The caps  18  engage with spherical surface bodies  7 ,  9 . Spherical surface bodies  7 ,  9  can fit into the depressions in the slide  2  and are secured to the slide  2  with bolt  26 . Then, gib  6  is secured to the frame  1 . Next, the wedge  12  and gib  5  are installed. The positioning of gib  5  and the wedge  12  is adjusted with the hollow screws  15  and bolt  16  while preserving the contact between the liner  11  and the cap  18 . Bolt  17  secures the wedge  12  and gib  5  to the frame  1 . 
     The surfaces of the liners  11  are adhesed to gibs  5 ,  6  and are positioned to form an angle α as shown in  FIG. 9 . Spherical surface body  7  and the cap  18  transfer pressure from the slide  2  to the section of the surface of the liner  11  that contacts the flat section of the cap  18 . 
     The force applied to the contact surfaces can be considered as separate lateral and longitudinal forces that restrict the slide  2  since the contact surfaces are inclined. Therefore, the slide  2  is restricted both laterally and longitudinally by the gibs  5 ,  6 . The angle α is approximately 120° and is determined from the status of the eccentric load of the press. The lateral projected area is larger than the longitudinal projected area when the lateral eccentric load is greater than the longitudinal eccentric load. When α is 120°, the projected area ratio between the lateral projected area and the longitudinal projected area is √3:1, i.e., approximately 1.7:1. 
       FIGS. 10 and 11  show an alternate embodiment of the present invention that is similar to the embodiment shown in  FIGS. 5 and 6 . However, the structure of the gibs and the method of installing the spherical surface bodies  7 ,  9  are different between the two embodiments. 
     The slide  2  is concave and gibs  5 ,  6  are convex in the embodiment of the present invention shown in  FIGS. 8 and 9 . However, the slide  2  is convex and gibs  24 ,  25 ,  33  are concave in the embodiment shown in  FIGS. 10 and 11 . The concave and convex shapes of the slide  2  and the gibs are reversed between these two embodiments. The angle α is 120° between the pair of liners  11  in the embodiment shown in  FIGS. 10 and 11 , which is similar to the embodiment shown in  FIGS. 5 and 6 . 
       FIG. 10  is a lateral cross-sectional view of  FIG. 1  along the gibs. The drawing is rotated 90° counter-clockwise to facilitate the presentation.  FIG. 11  is a detailed view of the upper gib section of  FIG. 10 . 
     Gib holders  13 ,  14  are secured to the frame  1  using bolts (not shown). The engagement units  13   a,    14   a  formed on gib holders  13 ,  14  are fitted into grooves on the frame  1 . 
     The hollow screw  15  with threads on the outer perimeter screws into a screw hole of gib holder  13 . Bolt  16  secures the hollow screw  15  to gib holder  13 . The end of bolt  16  is inserted into the hollow screw  15  and is screwed into the end of the wedge  12 . The end of the hollow screw  15  pushes the wedge  12 , thereby fixing the position of the wedge  12 . The hollow screw  15  and bolt  16  align the wedge  12  relative to gib holder  13 . 
     Gib  33  is aligned likewise relative to gib holder  14 . Furthermore, the wedge  12  is tapered so that gib  33  can be moved forward and backward relative to the slide  2 . Gib  33  and the wedge  12  are secured to the frame  1  with bolt  17  after gib  33  and the wedge  12  are aligned. 
     The sheet-like liner  11  is secured to gib  33  with a screw and is adhesed lengthwise along gib  33 . However, the liner  11  can be removed so that spherical surface bodies  7 ,  9  slide directly against gibs  24 ,  25 ,  33 . 
     Bolt  26  secures spherical surface body  7  to the slide  2 . Spherical surface body  7  fits into a depression on the slide  2 . The cap  18  is formed with a concave spherical surface section and is inserted between spherical surface body  7  and the liner  11 . The concave spherical surface section of the cap  18  engages with the convex spherical surface section of spherical surface body  7 . The cap  18  can pivot while engaged with the spherical surface of spherical surface body  7 . Additionally, the cap  18  is formed with a flat section, and the flat section and the liner  11  can slide against each other. 
     The position of gib  33  can be adjusted, but the position of gibs  24 ,  25  are fixed. Gibs  24 ,  25  do not need to be adjustable since gib  33  can be adjusted. 
     Gib  24  abuts against the projection  24   a  formed on the frame  1  and is secured to the frame  1  with the bolt  31 . The configuration of gib holder  14 , the hollow screw  15 , bolt  16  are the same as those described above. These components are used to adjust the position of gib  25 , and then, bolt  32  secures gib  25  to the frame  1 . 
     The cap  18  engages with spherical surface bodies  7 ,  9 . Spherical surface bodies  7 ,  9  fit into the depression in the slide  2  and are secured to the slide  2  with bolt  26 . Then, gib  24  is secured to the frame  1 . Next, the wedge  12 , gib  33 , and gib  25  are assembled. The positioning of gib  33 , gib  25 , and the wedge  12  are adjusted with the hollow screws  15  and bolt  16  while preserving the contact between the liner  11  and the cap  18 . Bolt  17  secures the wedge  12  and gib  33  to the frame  1 , and bolt  32  secures gib  25  to the frame  1 . 
     The surfaces of the liners  11  are adhesed to gib  33  and are positioned to form an angle α as shown in  FIG. 11 . Spherical surface body  7  and the cap  18  transfer pressure from the slide  2  to the section of the surface of the liner  11  that contacts the flat section of the cap  18 . 
     The force applied to the contact surfaces can be considered as separate lateral and longitudinal forces that restrict the slide  2  since the contact surfaces are inclined. Therefore, the slide  2  is restricted both laterally and longitudinally by the gib  33 . The angle α is approximately 120° and is determined from the status of the eccentric load of the press. The lateral projected area is larger than the longitudinal projected area when the lateral eccentric load is greater than the longitudinal eccentric load. If α is 120°, the projected area ratio between the lateral projected area and the longitudinal projected area is √3:1, i.e., approximately 1.7:1. 
       FIGS. 8 and 9  show the liners  11 , which serve as a pair of guide surfaces, positioned facing the center of the slide  2  so that the slide  2  forms a concave angle. However, the slide  2  forms a convex angle in the alternate embodiment shown in  FIGS. 10 and 11 . However, the structure shown in  FIGS. 8 and 9  can adjust to the effects of increasing temperature or the like in the slide  2 . The slide  2  expands when the temperature of the slide  2  increases relative to the gibs. The deformation of the slide  2  can be accommodated more easily when the slide  2  is formed with a concave angle as in  FIGS. 8 and 9 . 
     The surface contacts are formed between the spherical surface bodies and the gibs or between the caps and the gibs. Forming spherical contact surfaces prevents scorching and galling. The pressing operation is precise since the clearance for the gib is negligible, and the die guideposts do not have to be especially sturdy. Furthermore, the operation of the slide is simpler when using a component that engages with the spherical surface body. 
     The present invention is not limited to the embodiments described above with reference to the accompanying drawings. Various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

Technology Category: b