Patent Publication Number: US-6220137-B1

Title: Press apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a press apparatus. More specifically, the present invention relates to a press apparatus which makes it easy to remove a passive cam from the a lower die so as to improve workability. Moreover, the present invention relates to a press apparatus which is constituted so that a guide post is mounted across the nearest vicinity of a portion of the passive cam to which a processing member such as a punch is mounted, and is positioned on both sides of the processing member, and which can improve processing accuracy of a cam die as much as possible. 
     2. Description of the Background Art 
     A normal press apparatus is constituted so that a lower die is mounted to a bed of a press machine and a an upper die is mounted to a ram, and when the upper die is lifted and lowered, boring and forming processes are performed. Since the upper die is lifted and lowered in the vertical direction, the process in the lateral direction is performed in such a manner that the processing force in the vertical direction is converted into the processing force in the lateral direction by using a cam member. 
     The description will be given as to an example where a hole is bored in a side wall of a work by using the press apparatus having the cam member. 
     As shown in FIGS. 6 and 7, a locating member  104  for locating a work  103  is projected from a lower die  101 . A passive cam  107  having a punch  106  is provided on a position which faces a blanked hole  105  in a side wall of the work  103  so as to slide. A heel  108  is fixed to a rear portion of the passive cam  107 . A coil spring  109  is fitted into the passive cam  107  so as to be externally fitted in a point of a rod  110  through which the heel  108  is put. One end of the coil spring  109  is brought into contact with the heel  108 , and a nut  112  is fitted to the other end of the coil spring  109  via a washer  111 . As a result, the coil spring  109  pulls the passive cam  107  in which the hole was provided back to the work  103 . An actuation cam  118  is projected from the upper die  116  so as to be in a position which faces the passive cam  107 . 
     The upper die  116  is lowered and the actuation cam  118  advances the passive cam  107  against the applied force of the coil spring  109 , and a hole  105  is bored into the work  103  by the punch  106  and a die  125 . When the upper die  116  is lifted, the passive cam  107  is brought back by the applied force of the coil spring  109 . 
     Since the hole is bored in the side wall of the work  103 , as mentioned above, the passive cam  107  having the punch  106  approaches and separates from the work  103  so as to slide on the lower die  101 . Since the hole is bored by the punch  106  and the die  125 , the passive cam  107  must slide exactly. A flange  121  is projected from both sides of the lower part of the passive cam  107 , and a sidewise guide plate  122  and an upper guide plate  123  for guiding the flange  121  are fixed to the lower die  101 . A reference numeral  124  is a wear plate. 
     Since a processing member such as the punch  106  is mounted to the passive cam  107 , there occasionally arises a problem that a cutting edge of the punch  106  is nicked during the processing and thus it should be repaired. In the mounted state shown in FIG. 7, since the repair is impossible, the passive cam  107  should be removed from the lower die  101 . The heel  108  is removed and the passive cam  107  is guided by the sidewise guide plate  122  and the upper guide plate  123  so as to be moved towards the opposite-work side (backward). Thereafter, the passive cam  107  is passed through the sidewise guide plate  122  and the upper guide plate  123  so as to be removed from the lower die  101 . Therefore, it takes a long time to remove the passive cam  107  from the lower die  101 , and thus repairing workability is not good. 
     In addition, while the passive cam  107  slides repeatedly, it is worn out, and thus a gap is generated between the passive cam  107  and the sidewise guide plate  122 . As a result, the passive cam  107  cannot slide in the straight linear direction, and it slides non-linearly due to the gap. Since the punch  106  mounted to the passive cam  107  also slide non-linearly, the punch  106  cannot blank the die  125  in its whole periphery with a suitable clearance. As a result, burr occurs on the periphery of the blanked hole, and a high-quality boring process cannot be performed. Moreover, since the punch  106  and the die  125  carried out the blanking with burr, the gap causes the cutting edges of the punch  106  and the die  125  to be nicked. In order to attain the high-quality pressing process, the passive cam  107  should be moved straight and exactly without non-linear movement. 
     Further, since inclined weight due to the forming process is placed on the passive cam, the passive cam is apt to shift. Therefore, this shift is eliminated, and thus a product should be processed into a desired shape. 
     Furthermore, it is necessary to improve processing accuracy of a cam die as much as possible. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is devised in such points in view. In order to easily remove a passive cam from a lower die when the passive cam to which a processing member such as a punch was mounted to be repaired, the present invention provides a press apparatus having an actuation cam in an upper die, a passive cam in a lower die which is contact-pressed and driven by the actuation cam and to which a processing member such as a punch is mounted, a guide base in the lower die for sliding and guiding the passive cam, guide posts which are mounted across the guide base and move so as to slide the passive cam, and force applying means for applying a force to the passive cam towards an opposite-work side. In such a press apparatus, the passive cam is fitted onto the guide base so that when the guide posts mounted across the guide base are drawn out, the passive cam is lifted up and dismounted. 
     In addition, according to the present invention, the passive cam advances straight and moves along the guide posts in order to attain a high-quality pressing process. 
     Further, according to the present invention, the passive cam is externally fitted onto the guide base in order to lift and dismount the passive cam. 
     Furthermore, according to the present invention, inclined weight is placed on the passive cam due to the forming process or the like, and thus the passive cam is apt to shift. In order to eliminate this shift and to process a product into a desired shape, the sliding surface of the passive cam and the guide base has a vertical surface. 
     In addition, in order to improve processing accuracy using a cam die as much as possible, the guide posts are mounted across the nearest vicinity of a portion of the passive cam where the processing member such as the punch is mounted and are positioned on both sides of the processing member. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a side view showing a press apparatus according to a preferred embodiment of the present invention and showing a cross section of one portion of an upper die in a lowering state. 
     FIG. 2 is a side view showing a cross section of one portion in a bottom dead center position. 
     FIG. 3 is a sectional view of a middle portion of FIG.  2 . 
     FIG. 4 is a front view taken along line IV—IV of FIG.  2 . 
     FIG. 5 is a back view taken along line V—V of FIG.  2 . 
     FIG. 6 is a longitudinal section of a conventional press die. 
     FIG. 7 is a sectional view showing a guide section of a passive cam in a conventional press apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     There will be detailed below the preferred embodiments of the present invention with reference to the drawings. 
     The present embodiment refers to an example wherein a hole is bored in a work. 
     As shown in FIGS. 1 and 2, a locating member  3  for locating a work W is fixed onto a substrate  2  in a lower die  1  by a bolt  4 . 
     A passive cam  6  for mounting a boring punch  5  for boring the work W is positioned so as to face the work W. The passive cam  6  is provided onto guide posts  8  which are mounted across a guide base  7  so as to slide, and the guide base  7  is fixed to the substrate  2  by a bolt  9 . 
     A mounting plate  10  is fixed to a work processing side of the passive cam  6  by a bolt  11 . A punch plate  12  is fitted into the mounting plate  10  by a bolt  13  so that the boring punch  5  is mounted. A force is applied to a stripper plate  14  by a cushion rubber  15 , and the stripper plate  14  presses the work W before a hole is bored in the work W. A reference numeral  16  is a die which is fitted to the boring punch  5  and carries out piercing. 
     Supporting plates  17  and  18  are fittingly jointed with the forward and rearward ends of the guide base  7  by bolts  19  and  20 . Here, a side which is close to the work W is referred to as forward, and a side which is far from the work W is referred to as rearward. The guide posts  8  are mounted across the supporting plates  17  and  18  horizontally, and bushes  21  and  22  are pressed into the passive cam  6  and externally fitted onto the guide posts  8  so that the passive cam  6  slidable on the guide posts  8 . A length of the passive cam  6  between the supporting plates  17  and  18  is set so as to be shorter than a distance between the supporting plates  17  and  18 . This is because the passive cam  6  can move in the lateral direction. 
     The guide posts  8  are brought to the boring punch  5  as close as possible in order to improve boring accuracy using the boring punch  5 . Moreover, the guide posts  8  are positioned respectively on both sides of the boring punch  5 , namely, both sides of the boring punch  5  in the horizontal direction, as shown in FIG.  3 . Since the passive cam  6  is guided by the guide posts  8  so as to slide and the boring punch  5  is fixed to the passive cam  6 , as the boring punch  5  is closer to the guide posts  8 , it moves more accurately. Therefore, accurate processing can be carried out. When the guide posts  8  are positioned respectively on both the sides of the boring punch  5 , the boring punch  5  can be held in more accurate and exact position compared with the case that only one guide post  8  is fitted into the passive cam  6 , and thus accurate processing can be carried out. 
     A receiving plate  23  is positioned vertically on a rearward end surface of the passive cam  6  and is fixed by a bolt  24 . A force is applied to the lower end portion of the receiving plate  23  by a coil spring  26  which is positioned in a central cavity section  25  (see FIG. 3) of the guide base  7 . A supporting pin  27  is positioned horizontally in the center of the cavity section  25 , and its base end is fittingly joined with the supporting plate  17 , and its other end is inserted into the supporting plate  18 . The coil spring  26  is externally fitted to the supporting pin  27 , and washer plates  28  are fitted onto the supporting pin  27  so as to intervene between the rearward end of the coil spring  26  and the front surface of the receiving plate  23 . 
     FIG. 3 shows a state that the passive cam  6  is fitted into the guide base  7 . The passive cam  6  is externally fitted onto the guide base  7 . A vertical wear plate  31  and an oblique wear plate  32  are fixed to the inner surface of the passive cam  6  respectively by bolts  33  and  34 . A vertical sliding surface  35  and an oblique sliding surface  36 , which match with the vertical wear plate  31  and the oblique wear plate  32 , are formed on the guide base  7 . Even if the passive cam  6  is about to shift due to the forming process or the like, the passive cam  6  is fitted onto the guide base  7  so as to stretch thereover, and the vertical wear plate  31  of the passive cam  6  is guided on the vertical sliding surface  35  of the guide base  7 . Therefore, the passive cam  6  does not shift, and thus a high-quality product can be processed. 
     In addition, as shown in FIGS. 4 and 5, since the passive cam  6  is slid by the two guide posts  8  having a circular section which are mounted across both the upper sides of the supporting plates  17  and  18 , unstable sliding does not occur, namely, the passive cam  6  advances exactly, and thus accurate processing can be carried out. 
     Further, as shown in FIGS. 1 and 2, a base end small-diameter section  37  of the guide post  8  is fitted into a small-diameter hole  38  of the supporting plate  17 , and a point section  39  of the guide post  8  is fitted into a supporting hole  40  of the supporting plate  17 . A stop plate  42 , which contacts with point surfaces  41  of the guide posts  8 , is fixed to the rearward surface of the supporting plate  18  by a bolt  43  so that the guide posts  8  do not slip out of the supporting plates  17  and  18 . When the cutting edge of the boring punch  5  is nicked and thus it should be repaired, the bolt  43  is released so that the stop plate  42  is removed, and a bolt is fitted into screw holes  44  which are located on the point surfaces  41  of the guide posts  8 . Then, the guide posts  8  are moved rearwardly (the right direction in the drawing) so as to be drawn out. Since the small-diameter sections  37  of the guide posts  8  are simply fitted into the small-diameter holes  38 , the guide posts  8  can be drawn out easily by moving them in the right direction. 
     After the guide posts  8  are removed from the passive cam  6  and the guide base  7 , when the passive cam  6  is lifted up, as shown in FIG. 3, the passive cam  6  is guided on the vertical sliding surface  35  of the guide base  7  so as to easily move upward. As a result, the passive cam  6  can be dismounted, and the boring punch  5  or the like can be dismounted easily from the passive cam  6 . Therefore, the repairing workability is improved. 
     A wear plate  51  is fixed to a slanted surface of the rearward surface of the passive cam  6  by a bolt  52 . 
     In the upper die  61 , a actuation cam  63 , which contacts with the wear plate  51  on the rearward surface of the passive cam  6  in a lower die  1  and presses and drives the passive cam  6 , is fixed to a substrate  64  by a bolt  65 . 
     The following will describe an operation of this press apparatus. 
     First, as shown in FIG. 1, the work W is placed on the locating member  3  in the lower die  1 . 
     Next, the upper die  61  is lowered. FIG. 1 shows a lowering state of the upper die  61 . 
     The actuation cam  63  in the upper die  61  is brought into contact with the wear plate  51  of the passive cam  6  in the lower die  1  so as to drive the passive cam  6  towards the work W against the applied force of the coil spring  26 . At this time, the passive cam  6  is guided by the guide posts  8  so as to advance straight without non-linear movement. 
     The work W is pressed by the stripper plate  14 , and the boring punch  5  is fitted into the die  16  so as to bore a hole. FIG. 2 shows the upper die  61  in a bottom dead position. 
     When the boring process is completed, the upper die  61  starts to lift. The work W is pressed by the stripper plate  14  and the boring punch  5  moves rearwardly, and the passive cam  6  is also moved rearwardly by the applied force of the coil spring  26 . The upper die  61  stops in a top dead center position. 
     When a nicked cutting edge of the boring punch  5  is to be repaired, the bolt  43  is released, and the stop plate  42  is removed. A bolt or the like is fitted into the screw holes  44  of the guide posts  8 , and the guide posts  8  are drawn out rearwardly. At this time, since the guide posts  8  do not have a section whose diameter is larger than that of the supporting holes  40 , they can be drawn out smoothly. 
     In addition, as is clear from FIG. 3, the coil spring  26  and the supporting pin  27  are positioned in the cavity section  25  of the guide base  7 , and the passive cam  6  is externally fitted onto the guide base  7 . For this reason, when the passive cam  6  is lifted up, it can be lifted up easily because of no interference, and the passive cam  6  is guided on the vertical sliding surface  35  of the guide base  7  so as to be able to be lifted up smoothly. 
     In addition, since the passive cam  6  is guided by the two guide posts  8  having a circular section, it advances straight without non-linear movement, and thus accurate processing can be carried out. 
     In addition, the guide posts  8  are provided across the nearest vicinity of the portion of the passive cam  6  where the processing member such as the boring punch  5  is mounted, and they are positioned on both sides of the processing member. As a result, processing accuracy can be improved as much as possible. 
     The above embodiment described the boring process, but needless to say, the present invention can be applied to other pressing processes such as a notching process and a forming process. 
     In addition, the above embodiment described an example where the coil spring is used as force applying means, but this means is not limited to this. Therefore, elastic materials such as rubber and urethane rubber or a gas spring may be used. 
     Further, in the above embodiment, the guide base is constituted so that the guide posts are mounted horizontally, but the guide posts can be slanted or inclined. In this case, the guide base requires a height higher than a certain value in order to make it possible to draw out the guide posts. 
     As mentioned above, a press apparatus has an actuation cam in an upper die, a passive cam in a lower die which is pressed and driven by the actuation cam and to which a processing member such as a punch is mounted, a guide base in the lower die for sliding and guiding the passive cam, guide posts which are mounted across the guide base and move so as to slide the passive cam, and force applying means for applying a force to the passive cam towards an opposite-work side. In such a press apparatus, the passive cam is fitted onto the guide base so that when the guide posts mounted across the guide base are drawn out, the passive cam is lifted up so as to be able to be dismounted. As a result, when the passive cam to which the processing member such as the punch was mounted is repaired, the passive cam can be removed easily from the lower die. 
     In addition, since the passive cam advances straight through the guide posts, the present invention can perform high-quality pressing process. 
     Further, since the passive cam is externally fitted into the guide base, the passive cam is lifted up so as to be able to be dismounted. 
     Furthermore, since the sliding surface of the passive cam and the guide base has a vertical surface, inclined weight is placed on the passive cam at the time of the forming process or the like, and thus the passive cam is apt to shift. However, the present invention eliminates this shift and can process a product into a desired shape. 
     In addition, when the passive cam is lifted up, the sliding surface serves as a guiding surface, and thus the passive cam can be lifted up smoothly. 
     Further, the guide posts are mounted across the nearest vicinity of a portion of the passive cam where the processing member such as the punch is mounted and are positioned on both the sides of processing member. Therefore, processing accuracy can be improved as much as possible. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.