FULL ENCLOSED DIE FORGING APPARATUS

Abstract: The invention relates to a full enclosed die forging ap­ paratus provided with an upside die (150) and an under­ side die (170) disposed oppositely in a vertical direc­ tion between a slide (143) and a bolster (157), an up­ side cylinder mechanism (147) which is disposed on an up­ side die set plate (150) disposed on said slide (143) or at a lower end of this slide and urges said upside die (150) downwardly, an underside cylindermechanism (161) which is disposed on an underside die set plate (170) dis­ posed on said bolster (157) or at an upper end of this bolster and urges said underside die (161) upwardly, an upside punch (151) which is inserted in said upside die (150) and moves synchronously with the movement of said slide (143), an underside punch (171) which is inserted into said underside die (170) and supported by said bol­ ster (157), and a cam mechanism (176) having both punches (151, 171) operated to rush into dies, respectively, by moving said upside die (150) and underside die (170) to­ ward the underside punch (171) at a speed slower than the moving speed of said slide (143). It is an object of the invention to provide a full enclosed die forging apparatus which is capable of surely preventing a large force from working on the cam mechanism. This ob­ ject is solved by said cam mechanism is constructed so that said mechanism (176) is constructed so that said mechanism is operated by a lower end of a push pin (185) which is moved downwardly synchronously with the movement of said slide (143); and the upper end of said push pin (185) is made to abut directly or indirectly against a cylinder piston (187) which moves synchronously with the movement of said slide (143).

Description: Fully enclosed die forging in which raw material is molded in a cavity obtained by having a pair of dies contact with each other is being widely used recently for molding various products because yield of the raw material is high, and moreover, products having complex shapes may be manufactured with high accuracy. In this connection attention is drawn to the enclosed Figures 10 to 18 of the drawings. Conventionally, fully enclosed die forging of molded articles 11 represented by a spider of a triport type equal velocity joint for automobiles and so forth having shapes as shown in Fig. 10 and Fig. 11 is performed in such a manner that a cylindrical slag 13 as shown in Fig. 12 is inserted in cavities 19 and 21 formed with an upper die 15 and a lower die 17 as shown in left part of Fig. 13, and upper and lower punches 23 and 25 are made close to each other as shown in the right part of Fig. 13. Thereupon, when the shape of an aimed molded article 11 is of symmetric face with reference to a cross-section 27 having the maximum area as the molded article 11 described above, it is required to operate upper and lower punches 23 and 25 keeping face symmetrically with reference to a cross-section 31 of the maximum area of a cavity 29 while maintaining such a state that above mentioned upper die 14 and lower die 17 are made to contact with each other and enclosing force is applied. Because of such reason, a fully enclosed die forging apparatus as shown in Fig. 14 has been used conventionally. For such a fully enclosed die forging apparatus, a hydraulic or mechanical double action press is illustrated, and the left half of the drawing shows the state before molding and the right half of the drawing shows the state after molding, respectively. In the drawing, a reference numeral 11 denotes a molded article, 13 denotes a slag, 15 denotes an upper die, 17 denotes a lower die, 23 denotes an upper punch, 25 denotes a lower punch, 33 denotes a slide of a press, 34 denotes a bolster, 35 denotes a bed, 36 denotes an upper pressure pin and 37 denotes a lower pressure pin. In this fully enclosed die forging apparatus, first, the slag 13 is charged by hand or by a feeding device into a cavity 38 of the lower die 17. Next, when the slide 33 of the press descends, the upper and lower dies 15 and 17 come into contact with each other. In a hydraulic press, the slide 33 is urged downwardly by means of a hydraulic device, and in a mechanical press, the slide 33 stops at the bottom dead center, thereby to apply enclosing force to the upper and the lower dies 15 and 17. In succession, in a hydraulic press, a hydraulic unit which is of a different system from the unit for driving the slide 33 installed on the side of the slide 33 and on the side of the bed 35 is operated. In case of a mechanical press, a driving unit installed separately from the unit for driving the slide 33 is operated in the same manner as in the case of the hydraulic press. With this, the upper and lower pressure pins 36 and 37 are operated, the upper and lower punches 23 and 25 are moved toward above-mentioned cross-section 31, and the slag 13 is pushed out for working toward the cavity 29 formed by the upper and lower dies 15 and 17. Then, after molding, the slide 33 is ascended and the upper and lower dies 15 and 17 are separated. During ascending or at the upper limit thereof, the upper and lower punches 23 and 25 are operated by the hydraulic unit, and the molded article 11 is discharged out of the die. However, it is required to employ a double action press in order to apply such a fully enclosed die forging apparatus to a hydraulic press. Accordingly, a special purpose machine is required for the molded article 11, which spoils universality. Also, in the case of temperature change of pressure oil for operating the upper and lower punches 23 and 25, mixing of bubbles into the pressure oil and so forth are generated, the speed of the upper and lower punches 23 and 25 is changed, which makes it impossible to secure the product accuracy of the molded article 11. In order to avoid this, it has been required to add a correction mechanism which always performs flow control properly. Besides, in case of application to a mechanical press, a special purpose machine in which a drive unit for driving the upper punch 36 is provided on the side of the slide 33 and a pressure drive unit is also provided on the side of the bed 35 is required. Moreover, the upper and lower dies 15 and 17 being fitted together at the bottom dead point, enclosing force becomes unstable. Therefore, more enforcing force than required is applied to the press and the upper and lower dies 15 and 17, which makes the life of the metal mold shorter. A fully enclosed die forging apparatus according to the preamble of claim 1 is described in document JP-A-59,133,927. Fig. 15 shows a fully enclosed die forging apparatus disclosed in the aforesaid document. The left half of the Figure shows a state when fully enclosing is commenced, and the right half thereof shows the state when molding is completed at the bottom dead point. In the Figure, an upside die set plate 61 is fixed to a slide 60 of the press, and an insert plate 62 is inserted into this upside die set plate 61 with positioning by a knock pin 63. In said slide 60, a cushion pin 65 is urged downwardly by installing a cushion rod 64 which is urged downwardly by pressure liquid so as to ascend and descend freely. Similarly, a knockout rod 66 is provided in the slide 60 so as to ascend and descend freely. An upside die holder 67 is fixed to the upside die set plate 61, a cam holder 68 is fixed to this die holder 67, and furthermore, a first cam 69 is fixed to the cam holder 68. Besides, this first cam 69 drives the lower die through a second, a third and a fourth cam which will be described later. An upper die 70 is fitted to the inside of the upside holder 67 so as to ascend and descend freely. A punch block 71 and an upper punch 72 are fitted to the inside of this upper die 70 so as to ascend and descend freely. On the other hand, an underside die set plate 74 is fixed to a bolster 73, and an insert plate 75 is inserted into this die set plate 74. Further, in the bolster 73, a knockout rod 76 is provided so as to push up a knockout pin 77 at a constant timing by receiving a pushing-up force by pressure liquid or a mechanical device. In a similar manner, in the bolster 73, a cushion rod 78 is provided so as to urge a cushion pin 79 in the insert plate 75 upwardly. To the underside die set plate 74, an underside die hole 80 is positioned and fixed with a knock pin 81, and a plate 83 is positioned and inserted into this die holder 80 through a knock pin 82. Further, in the underside die holder 80, pats 84 and 85 are built in, and a spring 86 is installed under compressed condition between these pats 84 and 85. Besides, this spring 86 urges a lower die which is described later upwardly through a pressure pin 87 penetrating the plate 83 and said pat 84. Inside said spring 86, a cushion ring 88 is disposed so as to ascend and descend freely, and the urging force of the cushion pin 79 is arranged so as to be conveyed to a lower die 90 from a pressure pin 89 through this cushion ring 88. It is also arranged that, at the center of the upper surface of said insert plate 75, a die anvil 92 penetrating a punch block 91 so as to ascend and descend freely is provided, and a lower punch 93 is pushed up with a predetermined timing receiving pushing-up action of a knockout pin 77 by attaching a lower punch 93 on the upper part of the punch block 93. On the other hand, a guide 95 for guiding a second cam 94, etc. is fixed to said underside die holder 80. This second cam 94 is held by fitting slidably at a bore portion of the guide 95 having a circular form, and the bore portion of this cam 94 is fitted to the lower die 90. A step portion 94a of the cam 94 is engaged with the step portion of the lower die 90, and then the cam 94 is held by fitting slidably in a vertical direction only in a guide groove 96 along the center of the die 90. Further, a third and a fourth cams 97 and 98 which are held slidably in a circumferential direction only by the lower die 90 and the guide 95 are provided between the first cam 69 and the second cam 94. Thus, when the first cam 69 descends, the second cam 94 moves downwardly through the third and the fourth cam 97 and 98. Fig. 16 to Fig. 18 are drawings showing the locations and operating conditions of these cams. As seen from these drawings, two pieces of the first cams 69 are provided at diagonal locations of the cam holder 68 and formed in a cleat shape contracting downwardly, and the inclined faces of these first cams 69 are made to face between end inclined faces of adjacent third and fourth cams 97 and 98 from the upper part. Also, the second cam 94 is provided at a location the phase of which is shifted from the first cam 69 by 90° and formed in a cleat shape expanding downwardly, and by having the inclined surface face between point inclined faces of the third and the fourth cams 97 and 98 from the lower part, the third and the fourth cams 97 and 98 are moved in a circumferential direction thereby to push the second cam downwardly when the first cam 69 descends. Besides, the base ends of the third and the fourth cams 97 and 98 are formed into inclined faces going upwardly and the point ends are formed into inclined faces going downwardly. In a fully enclosed die forging apparatus thus constructed, the slag inserted into the cavity of the lower die 90 is formed under a condition that upper and lower dies 70 and 90 are fully enclosed, and is taken out by the operation of the knockout pin 77, etc. Thereupon, in this fully enclosed die forging apparatus, at the same time as upper and lower dies come into contact with each other, the third and the fourth cams 97 and 98 and the first cam 69 contact with each other as shown in Fig. 17. Therefore, when the slide 60 descends and the first cam 69 also descends, adjacent third cam 97 and fourth cam 98 are moved in a horizontal direction, and the second cam 94 which is put between both cams 97 and 98 is pushed downwardly. As the result, the die 90 which is engaged with the second cam 94 descends. The descending speed of this die 90 is made slower than the descending speed of the punch 72 by setting an angle of each cam face at a predetermined angle, and upper and lower punches 72 and 93 move relatively to upper and lower dies 70 and 90. In short, despite that upper and lower dies 70 and 90 descend at a lower speed than the descending speed of the upper punch 72, the lower punch 93 does not move. Accordingly, when the slide 60 is made to descend, upper and lower punches 72 and 93 rush into upper and lower dies 70 and 90, respectively, and move closely, thereby to perform expected molding. In such a conventional fully enclosed die forging apparatus, however, the cam 69 of the cam mechanism, which moves upper and lower dies 70 and 90 maintained with contact toward the lower punch 93 on the fixed side at a speed lower than the moving speed of the slide 60 and performs rushing operation of upper and lower punches 72 and 93 into upper and lower dies 70 and 90, respectively, is mounted directly on the cam holder 68. Therefore, there is a fear that the cam mechanism, etc. is damaged when an abnormal force, etc. is applied to the cam mechanism, etc. It is an object of the present invention which has been made to solve above-mentioned problems to provide a fully enclosed die forging apparatus which is capable of surely preventing a large force from working on the cam mechanism. This object is achieved by an apparatus as mentioned above further comprising the characterizing features of claim 1. Further embodiments of the invention are disclosed in the sub-claims. An embodiment of the present invention will be described hereinafter referring to the accompanying drawings. In the drawings: Fig. 1 is a longitudinal cross-sectional view showing an embodiment of a fully enclosed die forging apparatus according to the present invention; Fig. 2 is a top view of the support member shown in Fig. 1; Fig. 3 is a view looking along the arrow A of the support member shown in Fig. 2; Fig. 4 is a top view showing a state in which a horizontal cam and a vertical cam are disposed on the support member; Fig. 5 is an explanatory view for explaining the operation of the cam mechanism shown in Fig. 4; Fig. 6 is a top view showing an underside guide on which a push pin is disposed; Fig. 7 is a top view showing a ferrule disposed at the cylinder; Fig. 8 is a longitudinal cross-sectional view showing the state which the slag is inserted into the fully enclosed die forging apparatus shown in Fig. 1; Fig. 9 is a longitudinal cross-sectional view showing a cylinder of another embodiment of the fully enclosed die forging apparatus according to the present invention; Fig.10 is a top view showing an example of an article manufactured by fully enclosed die forging; Fig.11 is a longitudinal cross-sectional view of Fig. 10; Fig.12 is a side view showing a slag; Fig.13 is a longitudinal cross-sectional view showing a conventional fully enclosed die forging method; Fig.14 and Fig.15 are longitudinal cross-sectional views showing conventional fully enclosed die forging apparatus, respectively; and Fig.16 through Fig.18 are explanatory views showing the cam mechanism shown in Fig.15. Fig.1 shows an embodiment of a fully enclosed die forging apparatus according to the present invention. In this fully enclosed die forging apparatus, an upside die set plate 144 is fixed to a slide 143 of a press. An upside insert plate 145 is fixed with a bolt 146 to this upside die set plate 144. An upside cylinder 147 is formed on the upside die set plate 144, and an upside piston 148 is inserted into this upside cylinder 147. An upside actuating pin 149 is disposed on the underside of the upside piston 148, and the lower end of this upside actuating pin 149 abuts against an upper face of an upside die 150. An upside punch 151 is inserted at the central portion of the upside die 150, and a cavity 153 corresponding to the shape of an article 152 to be molded is formed at the lower part of this upside die 150. Penetrating through central portions of the upside die set plate 144 and the upside insert plate 145, a knockout pin 154 is disposed so as to ascend and descend freely. An upside die holder 155 is fixed to the upside die set plate 144, and a cam mechanism operating portion 156 for operating a cam mechanism which will be described later is disposed on an outer circumference of this upside die holder 155. On the other hand, an underside die set plate 158 is fixed to the bolster 157 of the press. An underside insert plate 159 is fixed with a bolt 160 to this underside die set plate 158. An underside cylinder 161 is formed in the underside die set plate 158, and an underside piston 163 is inserted into this underside cylinder 161. An underside actuating pin 164 is disposed on the upper face of the underside piston 163, and the upper end of this underside actuating pin 164 abuts against a lower face of a support member 166 contained in an underside die holder 165 penetrating through the underside die holder 165. The underside die holder 165 is fixed to the underside die set plate 158 with a bolt 167, and an underside holder 168 and an underside guide 169 are disposed in succession on the upper part of this underside die holder 165. An underside die 170 is inserted into the underside guide 169. An underside punch 171 is inserted into the central portions of the underside die 170 and the support member 166, and a cavity 172 corresponding to the shape of the article 152 to be molded is formed in the upper part of the underside die 170. Penetrating through central portions of the underside die set plate 158, the underside insert plate 159 and the underside die holder 165, a knockout pin 173 is disposed so as to ascend and descend freely. An auxiliary cylinder 174 is disposed in the underside holder 165, and an auxiliary piston 175 the upper end of which is abutted with the support member 166 through a pin is contained in this auxiliary cylinder 174. Further, in this embodiment, a cam mechanism 176 for moving this support member 166 is disposed in the support member 166. This cam mechanism 176 is operated in such a manner that the upside die 150 and the underside die 170 which are maintained with contact are moved toward an underside punch 171 on the fixed side pursuant to the movement of the slide 143 at a speed lower than the moving speed of the slide 143 thereby to have upside and underside punches 151 and 171 rush into upside and underside dies 150 and 170, respectively. That is, a large diameter portion 177 is formed at the lower part of the support member 166 as shown in Fig. 2 and Fig. 3. At this large diameter portion 177, cutout portions 178 are formed at four locations at angles of 90°, and cam faces 179 are formed on these cutout portions 178, respectively. Cam faces 181 of horizontal cams 180 in rectangular parallelepiped shape are made to abut against these cam faces 179 as shown in Fig. 4 and Fig. 5. Also, cam faces 184 of vertical cams 183 in plate form are made to abut against cam faces 182 formed at another ends of horizontal cams 180. The lower ends of the push pins 185 of the cam mechanism operating portion 156 shown in Fig. 1 are made to abut against the upper faces of the vertical cams 183. Besides, in Fig. 4 and Fig. 5, the left side of the Figure shows the state when the vertical cam 183 is located at the upper limit position, and the right side thereof shows the state when the vertical cam 183 is pushed by the push pin 185 and located at the lower limit position. The cam mechanism operating portion 156 includes a piston 186 which abuts against the upper face of the push pin 185 as shown in Fig. 1, and a piston part 186a formed at the upper part of this piston 186 is inserted into a push pin cylinder 187. It is arranged that an oil at a certain pressure is supplied into this cylinder 187 so that the pin 185 may move upwardly when a great force is applied to the piston 186. The cylinder 187 is supported by a ring ferrule 188, and this ferrule 188 is fixed to the upside die holder 155 with a bolt 189. Further, a screw portion 190 is formed on the outer circumference of the upside die holder 155, and a position control mechanism consisting of a nut 191 for determining simultanously upper end positions of disposed plurality of cylinder 187 is screw-engaged with this screw portion 190. Besides, the push pins 185 and the cylinders 187 are disposed at four positions in a rectangular shape corresponding to the positions of vertical cams 183 as shown in Fig.6 and Fig.7. As shown in Fig. 8, in the fully enclosed die forging apparatus thus constructed, the slag 13 inserted into the cavity 172 of the underside die 170 is formed under fully enclosed state produced by the upside die 150 and the underside die 170 abutting against each other, and taken out by the action of the knockout pin, etc. And, in the fully enclosed die forging apparatus thus constructed, the lower face of the piston 186 and the upper face of the push pin 185 abut against each other when the upside die 150 and the underside die 170 come into contact with each other. Thereafter, when the slide 143 descends further and the push pin 185 also descends, the vertical cam 183 descends as shown in Fig. 4 and in the right side of Fig. 5. With this, the horizontal cam 180 is pressed toward the cam face 179 of the support member 166, the support member 166 moves downwardly, and at the same time, the underside die 170 also moves downwardly. Here, when it is assumed that cam angles of the vertical cam 183 and the horizontal cam 180 are α and β, respectively, the descending speed ratio of the support member 166 to the vertical cam 183 is given as follows: tan α x tan β Accordingly, after the vertical cam 183 comes in contact with the horizontal cam 180, the underside die 170 descends at a speed lower than that of the upside punch 151 as the upside punch 151 descends, and the upside punch 151 and the underside punch 171 move relatively to the upside die 150 and the underside die 170. That is, despite that the upside die 150 and the underside die 170 descend at a speed lower than the descending speed of the upside punch 151, the underside punch 171 does not move. Therefore, when the slide 143 is made to descend, the upside punch 151 and the underside punch 171 rush into the upside die 150 and the underside die 170, respectively, so as to move closely, thereby to perform expected molding. When, for example, after the upside die 150 and the underside die 170 have contacted with each other, these are made to descend at a half of the descending speed of the slide 143, viz. when a molded article is of symmetric face related to the cross-section of the maximum area, both of angles of the vertical cam 183 and the horizontal cam 180, α and β, may be selected at 35 degrees 15 minutes 52 seconds theoretically. Here, when it is assumed that the generating force of the upside cylinder 147 is at P U , the generating force of the underside cylinder 161 is at P L , the generating force of the auxiliary cylinder 174 is at P S , and the force of the horizontal cam 180 to push down the support member 166 is at P C, the force F U applied to the upside die is: F U = P U and the force F L applied to the underside die is: F L = P L + P S - P C When the molded article has a symmetric form with reference to the cross-section of the maximum area, F U = F L is obtained. Namely, P C = (P L - P U ) + P S is obtained. Here, P C >0 is required in order that respective cam faces are maintained by contact with each other. Such a condition is satisfied by P L >P U even if there were no auxiliary cylinder (P S =0). However, for the purpose of stabilizing the cam operation, viz., in order to stabilize the relative speed of the upside punch 151 and the underside punch 171 against the dies 150 and 170 during molding and to obtain a molded article of high accuracy, it is desired that the urging force of each cam face, viz., P C is constant. However, P L and P U fluctuate because of viscosity variation of the pressure liquid, mixing of bubbles into the pressure liquid and so forth, thus, P C = P L - P U (when P S =0) is hardly constant. In order to stabilize the urging force of the cam face, it is only required to make the cylinder diameters of the upside cylinder 147 and the underside cylinder 161 equal, and to supply pressure liquid from a common pressure liquid feeding device. With such arrangement, even if viscosity variation of pressure liquid and mixing of bubbles into pressure liquid are generated, P L = P U , and in turn P C = P S , is always obtained. If a pressure liquid at an atmospheric pressure is supplied to the auxiliary cylinder, P S , viz., P C becomes constant and the urging force applied to the cam face becomes stabilized, thus a molded article of high accuracy is obtainable. Here, in the fully enclosed die forging apparatus thus constructed, the cam mechanism 176 is constructed so as to be operated by the lower end of the push pin 185 which is moved downwardly synchronously with the movement of the slide 143, and at the same time, the upper end of the push pin 185 is made to abut directly against the piston of the cylinder 187 moving synchronously with the movement of the slide 143, viz., the upper end of the piston 186 having the piston portion 186a at the upper part thereof. Accordingly, when a great force is applied to the cam mechanism 176 by the movement of the slide 143, the piston 186 moves upwardly against the pressure of the pressure liquid in the cylinder 187, and no great force is applied to the cam mechanism 176. Accordingly, it is possible to surely prevent a great force from being applied to the cam mechanism 176, and thus, to prevent the damage on the cam mechanism 176, etc. Further, in the fully enclosed die forging apparatus thus constructed, the cam mechanism 176 which moves the upside die 150 and the underside die 170 under fully enclosed state is composed of the support member 166 consisting of an underside pat which is installed between the underside die 170 and the underside cylinder 161 mechanism for supporting the underside die 170 directly and urged upwardly directly by means of the underside cylinder 161 mechanism, the push pin 185 moved downwardly synchronously with the movement of the slide 143, and the cam mechanism 176 which moves the support member 166 downwardly at a speed slower than the moving speed of the slide 143 by the movement of this push pin 185. Accordingly, it is no longer required to dispose respective cams on the outer circumference of the underside die and to descend the underside die directly with these cams as in a conventional case. With this, the degree of freedom for the arrangement of the cam mechanism is increased, and it becomes possible to construct the cam mechanism 176 with linear cams as shown in Fig. 2 through Fig. 5, thus the cam mechanism may be simplified by a large margin as compared with a conventional case. Furthermore, in the fully enclosed die forging apparatus thus constructured, the upper face of the cylinder 187 abuts against the lower surface of a nut 191 which is a position control mechanism, thereby to position the vertical position of the cylinder 187. Therefore, it is possible to perform fine adjustment of positions of a plurality of cylinders 187 at the same time by loosening the ferrule 188 and adjusting the position of the nut 191, and it is also possible to adjust positions, H₁ and H₂ dimensions (Fig.11), of the extruding portion of the molded article easily. This is effectual for the adjustment in case of correction of dimensional variation of the molded article in mass production and replacement of a metal mold with a new metal mold. Fig. 9 shows a cylinder in another embodiment of a fully enclosed die forging apparatus according to the present invention. In this embodiment, a piston 194 is contained in a cylinder 192 for pressing a push pin 193 downwardly, and a groove 195 is formed on the side surface of this piston 194 and a seal portion 196 if formed on the lower surface thereof. Further, a liquid feeding hole 197 is provided in the upper part of the cylinder 192, and a drain hole 198 is provided at the lower part of the cylinder 192. In such a cylinder 192, the push pin 193 moves upwardly when a great force is applied to the push pin 193. With this, as shown in the right side of Fig. 9, the piston 194 moves upwardly and a clearance 199 is formed between the seal portion 196 of the piston 194 and the cylinder 192. As shown with an arrow mark in the Figure, the pressure liquid in the cylinder 192 passes through the groove 195 of the piston 194 and the clearance 199, and flows out of the cylinder 192 through the drain hole 198 thereafter. As the result, the pressure in the cylinder 192 drops sharply, which makes it possible for the piston 194 to move further upwardly, thereby to remove the force acting on the push pin 193 quickly. Besides, in above-mentioned embodiment, it has been described as an example that the upper surface of the support member 166 is made to abut against the lower surface of the underside die 170, and the cam mechanism 176 is disposed on this support member 166. However, the present invention is not limited to such an embodiment, but it is needless to say that a cam mechanism may be formed on the piston of the underside cylinder and so forth, for instance. As described above, according to the fully enclosed die forging apparatus in Claim 1, the cam mechanism is constructed so as to be operated by the lower end of the push pin moved downwardly synchronously with the movement of the slide, and the upper end of the push pin is also made to abut against the piston of the cylinder moving synchronously with the movement of the slide directly or indirectly. Accordingly, it is possible to surely prevent a great force being applied to the cam mechanism. Also, according to the fully enclosed die forging apparatus in Claim 2, a position control mechanism is provided for adjusting positions of a plurality of cylinders. Therefore, the position of the extruding portion of the molded article may be adjusted simply.

Claims: A fully enclosed die forging apparatus comprising a slide (143) having an upside die set plate (144), a bolster (157) having an underside die set plate (158), an upside die (150) and an underside die (170) disposed opposedly in a vertical direction between said slide (143) and said bolster (157), an upside cylinder mechanism (147) disposed on said upside die set plate (144) which urges said upside die (150) downward, an underside cylinder mechanism (161) disposed on said underside die set plate (158) which urges said underside die (170) upward, a support member (166) for supporting the underside die (170), said support member (166) being located between the underside die (170) and the underside cylinder mechanism (161), an upside punch (151) inserted in said upside die (150) that moves synchronously with the movement of said slide (143), an underside punch (171) inserted in said underside die (170) and supported by said bolster (157) and a cam mechanism (176), characterized by said cam mechanism (176) comprising at least one horizontal cam (180) and at least one vertical cam (183) in contact with said horizontal cam, said support member (166) and horizontal cam (180) being interengaged, at least one push pin (185; 193) having an upper end and a lower end, a push pin cylinder (187; 192) having a piston (186; 194) which abuts the upper end of said push pin for movement thereof synchronously with movement of the slide (143), the lower end of the push pin (185; 193) contacting the vertical cam (183) for corresponding movement thereof, to cause descending movement of the support in response to movement of the horizontal cam (180) produced by the vertical cam (183), whereby to cause both of said punches (151, 171) to accelerate into said dies (150,170) by moving said upside die (150) and said underside die (170) downwardly at a slower speed than the moving speed of said slide (143). A fully enclosed die forging apparatus as defined in claim 1 wherein adjusting means (191) are provided for determining the position of said push pin cylinder (187; 192). A fully enclosed die forging apparatus as defined in claim 2 wherein the adjusting means (191) comprise a plurality of such push pins (185; 193) and corresponding push pin cylinders, each such push pin cylinder (187; 193) being vertically positionable relative to the press slide (143), and wherein said adjusting means further comprise a nut (191) threadably engaged to an upside die holder (155) being fixed to the upside die set plate (144), said nut contacting each of the push pin cylinders (187; 192) at the uppermost ends thereof for simultaneously determining the vertical positions of each of said cylinders (187; 192). A fully enclosed die forging apparatus as defined in one of claims 1 to 3 wherein said cam mechanism (176) comprises a plurality of linear horizontal cams (180) operated by vertical cams (183), the horizontal cams interengaging said support member (166). A fully enclosed die forging apparatus as defined in one of claims 1 to 4 wherein the cam mechanism (176) includes a plurality of vertical cams (183) engaging a corresponding plurality of linear horizontal cams (180) having cam faces (181) engaging a piston of said underside cylinder mechanism (161). A fully enclosed die forging apparatus as defined in anyone of the foregoing claims wherein the cam mechanism (176) includes multiple push pins (185; 193) A fully enclosed die forging apparatus as defined in one of the foregoing claims, characterized by the push pin cylinder (192) comprising said piston (194) having a groove (195) formed on its side surface, a seal portion (196) formed on its lower surface, a liquid feeding hole (197) provided in the upper part of said cylinder (192), a drain hole (198) provided at the lower part of said cylinder (192), said push pin (193) in abutting relationship to said piston (194) for causing said push pin to move upwardly upon forced entrance of pressure liquid through said liquid feeding hole (197) into said cylinder (192) so as to cause said piston (194) to move upwardly forming a clearance (199) with said cylinder (192) at said seal portion (196) allowing escape of such pressure liquid from the cylinder thereby causing pressure in said cylinder to sharply decrease, permitting said piston (194) to move further upwardly, for thereby quickly removing force from said push pin (193).

Inventors: ISHINAGA, NOBUYUKI
Applicants: AIDA ENGINEERING LTD.
Application year: 1988
Main classification: B21J5
IPC codes: B21K1, B21J5