Abstract:
Improved die arrangements are provided whereby both an upper die and a lower die can easily be loaded into and unloaded from their respective die holders in a die exchanging operation. An improved die apparatus in a pressing machine in which an upper die set is securely loaded in an upper die holder fastened to a slide side for a pressing operation, comprises an arrangement whereby the upper die set is held in the upper die holder so that the upper die set can be extracted downwards from the upper die holder, wherein the upper die holder is provided with stopper means adapted to engage with the upper die set to hold the upper die set in place and adapted to disengage from the upper die set to allow the upper die set to disengage from the upper die holder.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a die apparatus and a die exchanging method in a pressing machine.  
         [0003]     2. Description of the Prior Art  
         [0004]     A die apparatus in a pressing machine comprises a lower die unit in which a lower die set containing lower die members is received in a lower die holder and an upper die unit in which an upper die set containing upper die members is received in an upper die holder. And, with the lower and upper die holders securely fixed to a lower and an upper die plate, respectively, which are in turn securely fixed to a bolster and a slide, respectively, the lower and upper die units are securely held by the bolster and the slide, respectively.  
         [0005]     An existing die apparatus of this type, in which the lower and upper die units are each dealt with as an assembly, has been so designed that when the lower and upper dies are each exchanged, the lower and upper die units each with its die holder must wholly be removed from the bolster and slide, respectively, and in the outside of the machine each of the lower and upper dies must, by means of a chain hoist or the like, be extracted upwards from the die holder, together with a plate in which it is circumferentially fitted and must then be decomposed.  
         [0006]     Thus, in the conventional die apparatus, since it is necessary to remove two such die units together with their respective die holders into the machine&#39;s outside each time a lower and an upper die are exchanged and further to extract upwards each of the lower and upper dies from its die holder, together with a plate in which it is circumferentially fitted, respectively, there has been encountered the problem that quite a time-consuming die exchanging operation is required.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     With the forgoing taken into account, the present invention has an object aimed at providing an improved die apparatus for a pressing machine, having an upper and a lower die unit, whereby an upper die set can easily be unloaded from an upper die holder without unfastening the upper die holder from an upper die plate and likewise a lower die in a lower die set can easily be unloaded from a lower die holder without unfastening the lower die holder from a lower die plate, and whereby an upper die and a lower die set can both be exchanged easily.  
         [0008]     In order to achieve the object mentioned above there is provided in accordance with the present invention a die apparatus in a pressing machine in which an upper die set is securely loaded in an upper die holder fastened to a slide side for a pressing operation, characterized in that it comprises an arrangement whereby the upper die set is held in the upper die holder so that the upper die set can be extracted downwards from the upper die holder, wherein the upper die holder is provided with stopper means adapted to engage with the upper die set to hold the upper die set in place and adapted to disengage from the upper die set to allow the upper die set to disengage from the upper die holder.  
         [0009]     The present invention also provides a die apparatus in a pressing machine in which a lower die is securely loaded in a lower die fastened to a bolster side and an upper die set is securely held in an upper die holder fastened to a slide side for a pressing operation, characterized in that it comprises: a first arrangement whereby the lower die is held in the lower die holder so that the lower die can be extracted upwards from the lower die, wherein below the lower die there is provided a lower die lifting means for lifting up the lower die until it lies higher in position than an upper face of the lower die holder; and a second arrangement whereby the upper die set is held in the upper die holder so that the upper die set can be extracted downwards from the upper die holder, wherein the upper die holder is provided with stopper means adapted to engage with the upper die set to hold the upper die set in place and adapted to disengage from the upper die set to allow the upper die set to disengage from the upper die holder.  
         [0010]     The present invention further provides a die exchanging method for a pressing machine, characterized in that it comprises the steps of: raising a lower die lifting means to lift up a lower die in a lower die holder until it lies higher in position than an upper face of the lower die holder, thereby unloading the lower die from the lower die holder; then, placing an upper die mounting and demounting jig on the raised lower die lifting means so that the upper die mounting and demounting jig lies coaxially with the lower die lifting means; moving down a slide having an upper die set fastened thereto via an upper die holder, followed by placing the upper die set on the upper die mounting and demounting jig so that the upper die set lies coaxially with the upper die mounting and demounting jig; releasing holding of the upper die set by the upper die holder, followed by raising the slide to allow the upper die set to be extracted downwards and thereby unloaded from the upper die holder; removing the upper die set from the upper die mounting and demounting jig; mounting a new upper die set on the upper die mounting and demounting jig so that the new upper die set lies coaxially with the upper die mounting and demounting jig; moving down the slide to allow the new upper die set to engage with the upper die holder, followed by fastening the new upper die set to the upper die holder; moving up the slide having the new upper die set held by the upper die holder; removing the upper die mounting and demounting jig from the raised lower die lifting means and mounting a new lower die on the latter; and lowering the lower die lifting means having the new lower die mounted thereon until the latter is loaded in the lower die holder.  
         [0011]     According to the present invention, an upper die set is allowed to exit from the upper die holder by loosening the stopper means, and members making up the upper die set can be decomposed in the state that the upper die set is removed from the upper die holder. Also, a lower die is allowed to exit upwards from the lower die holder by the lower die lifting means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     These and other objects, features and advantages of the present invention and other manners of its implementation will be more readily apparent, and the invention itself will also be better understood, from the following detailed description when taken with reference to the drawings attached hereto showing certain illustrative forms of implementation of the present invention. In the drawings:  
         [0013]      FIG. 1  is a cross sectional view illustrating a die apparatus according to the present invention in one form of implementation thereof;  
         [0014]      FIG. 2  is a cross sectional view illustrating the die apparatus in the state that a lower die has been unloaded;  
         [0015]      FIG. 3  is a cross sectional view illustrating the die apparatus in the state that an upper die is being unloaded; and  
         [0016]      FIG. 4  is a cross sectional view illustrating the die apparatus in the state that the upper die has been unloaded. 
     
    
     DETAILED DESCRIPTION  
       [0017]     An explanation is now given of one form of implementation of the present invention with reference to the Drawing Figures. In the Figures there are shown a lower die plate  1  fastened onto a bolster B, an upper die plate  2  fastened to a lower surface of a slide S, a lower die unit  3  fastened to the lower die plate  1 , and an upper die unit  4  fastened to the upper die plate  2 .  
         [0018]     The lower die unit  3  as shown comprises a die holder  5  fastened to the lower die plate  1 , and a lower die set  6  received in the lower die holder  5 . The lower die set  6  includes a ring plate  7  mounted on the lower die plate  1 , a lower die  6   a  mounted on the ring plate  7  so as to be slidably movable up and down in the lower die holder  5 , and a knockout member  9  disposed in axial center of the ring plate  7  so as to be movable up and down and having its upper end facing the lower die  6   a  and its lower end opposed to the tip end of a knockout pin  8 . The lower die set  6  also includes an imposition ring  10  mounted on the lower die plate  1  so as to fit over the ring plate  7 , lift pins  11  and a lift pin guide member  12  fitted between the imposition ring  10  and the lower die holder  5  for guiding the lift pins  12  axially thereof, and a lower die takeout ring  13  disposed between the lift pin guide member  12  and the lower die  6   a  so as to be movable up and down. The lift pins  11  have their upper ends opposed to a lower face of the lower die takeout ring  13 . The lower die  6   a  in the state that it is mounted on the ring plate  7  is fastened to the lower die holder  5  by a clamp means  14 .  
         [0019]     With the clamp means  14  unfastened and detached, the lower die  6   a  is lifted up by thrusting the same up with the lift pins  11  via the lower die takeout ring  13  until the lower end faces of the lower die  6   a  lies higher in position than the upper end face of the lower die holder  5 .  
         [0020]     The upper die unit  4  as shown comprises an upper die holder  15  fastened to the upper die plate  2 , and an upper die set  16  received in the upper die holder  15  so that the former can be extracted downwards from the latter. The upper die set  16  is held in place by a plurality of stopper bolts  17  passing through the upper die holder  15  radially thereof.  
         [0021]     The upper die set  16  comprises an upper plate member  18  and an upper die casing  19  on which it is mounted, and a punch  20  and an inner casing  21  which together constituting an upper die are received in the upper die casing  19  coaxially therewith so that they can be extracted from it upwards. The upper die casing  19  has a peripheral surface area  19   a  conically tapered where it is held in place by the stopper bolts  17  brought into engagement therewith, and terminates with a cylindrical section  22 .  
         [0022]     In the upper die set  16 , each of the upper die plate member  18 , the upper die casing  19 , the punch  20  and the inner casing  21  has a hanger tap or taps  23  and is made capable of being hung up by a wire or wires via a hunger fitting or fittings in thread engagement therewith.  
         [0023]     With the apparatus so made up as mentioned above, the lower die  6   a  is loaded with a formable material, and then the slide S is moved down to move the upper die unit  4  down whereby the material is formed into a formed product  24  as shown, by the lower die  6   a  and the upper die made of the punch  20  and the inner casing  21 . Then, the formed product  24  is removed from the lower die  6   a  by raising the knockout member  9  after lifting up the upper die unit  4 .  
         [0024]     Mention is next made of a way of exchanging the lower die  6   a  and the upper die set  16  for the lower die unit  3  and the upper die unit  4 .  
         [0025]     The lower die  6   a  is exchanged upon lifting up the upper die unit  4 . Referring to  FIG. 1 , first the clamp means  14  is unfastened and detached to release clamping of the lower die  6   a  to the lower die holder  5 . Next, the lift pins  11  are raised to lift up the lower die takeout ring  13  with their upper ends and in turn to lift up the lower die  6   a  until its lower end lies higher in position than the upper end of the lower die holder  5  as shown in  FIG. 2 . Then, the lifted up lower die  6   a  is moved horizontally or hung up so as to be placed, for example, on a table (not shown) that has been prepared besides the upper die holder  15 . The lower die  6   a  is thus taken out of the pressing machine. For setting a new lower die  6   a  in the lower die holder  5 , a manner reverse to the above mentioned manner of removal is followed.  
         [0026]     The upper die set  16  can be exchanged as stated below with reference to  FIGS. 3 and 4 . Here, the upper die set  16  is exchanged midway of the above mentioned operation of exchanging the lower die  6   a , namely in the state where the lower die  6   a  is removed from the lower die holder  5 . Further, in exchanging the upper die set  16 , use is made of a cylindrical upper die mounting and demounting jig  25 .  
         [0027]     The upper die mounting and demounting jig  25  is provided in its lower side with a lower side fitting region  25   a  in fitting with the inner periphery of the lower die takeout ring  13  and in its upper side with an upper side fitting region  25   b  in fitting with the outer periphery of the cylindrical section  22  at the lower end of the upper die casing  19 .  
         [0028]     In the state that the lower die  6   a  is removed from the lower die holder  5  as mentioned above, the upper die mounting and demounting jig  25  is set upon the raised lower die takeout ring  13  as shown in  FIG. 3 . Then, the slide S is moved down to a position at which only a small spacing exists between the lower face of the upper die casing  19  in the upper die unit  4  and the upper face of the upper die mounting and demounting jig  25 . Thereafter, the lift pins  11  are pushed up to raise the lower die takeout ring  13  by a distance equal to the abovementioned small spacing and thereby to bring the upper face of the upper die mounting and demounting jig  25  into contact with the upper die casing  19 . Now, the cylindrical section  22  of the upper die casing  19  has come into fitting with the upper side fitting region  25   b  of the upper die mounting and demounting jig  25 .  
         [0029]     Then, loosening the stopper bolts  17  to retract its tip end out of the inside of the upper holder  15  sets the upper die set  16  free from holding by the stopper bolts  17 . Then, moving up the slide S leaves the upper die set  16  placed on the upper die mounting and demounting jig  25  while lifting up the upper die holder  15  as shown in  FIG. 4 .  
         [0030]     The slide S is then moved up to lifting up the upper die holder  15  further until the slide S reaches its upper dead point. This produces and secures a wide space between the upper die holder  15  and the upper die set  16  extracted therefrom, where the upper die plate  18 , the punch  20 , the inner casing  21  and the upper die casing  19  are each demounted in this order. They are demounted by hanging them with wires tied to hanger accessories threaded with hanger taps  23  secured to them. In this case, lowering the lower die takeout ring  13  to lower the upper face of the upper die plate  18  will facilitate demounting these die set members.  
         [0031]     When an another upper die set  16  is loaded in the upper die holder  15 , that upper die set  16  is mounted on the upper die mounting and demounting jig  25  whereafter the slide S is moved down, and the upper die set  16  is accepted in the upper die holder  15  and is held in place with the stopper bolts  17 . Then, using the upper die mounting and demounting jig  25  to dispose the upper die set  16  coaxially with the upper and lower die holders  15  and  5  facilitates accurately mounting the upper die set  16  in the upper die set  16  in the upper die holder  15 .  
         [0032]     A die apparatus according to the present invention allows an upper die set  16  to be removed from an upper die holder  15  to lie below it without removing the upper die set receiving upper die holder  15  from a slide S, thereby permitting the upper die set to be exchanged easily. The die apparatus also allows a lower die  6   a  in a lower die set  6  to be easily removed from a lower die holder  5  without removing the lower die set receiving lower die holder  5  from a bolster, thereby permitting the lower die to be exchanged easily.  
         [0033]     A die changing method according to the present invention allows the upper die set  16  to be removed from the upper die holder as it is held coaxial with the upper die holder  15 . When an another upper die set  16  is loaded in the upper die holder  15 , using the upper die mounting and demounting jig  25  allows that upper die  16  to be disposed coaxially with the upper and lower die holders  15  and  5 . Thus, any upper die set  16  can be loaded into and unloaded from the upper die holder easily.  
         [0034]     Although the present invention has hereinbefore been set forth with respect to certain illustrative embodiments thereof, it will readily be appreciated to be obvious to those skilled in the art that many alterations thereof, omissions therefrom and additions thereto can be made without departing from the essences of scope of the present invention. Accordingly, it should be understood that the invention is not intended to be limited to the specific embodiments thereof set forth above, but to include all possible embodiments that can be made within the scope with respect to the features specifically set forth in the appended claims and to encompass all the equivalents thereof.