Press device

Abstract: The present invention provides a press device comprising a slide cam base (21), a slide cam (19) guided by the slide cam base for mounting a machining member such as a punch (73), an urging member (25) provided between the slide cam base and the slide cam for urging the slide cam, and an actuating cam (4) for abutting the slide cam to be driven, wherein the slide cam is slidably provided on a circular-section guide post (24) installed on the slide cam base. The urging member (25) comprises a gas spring. The guide post (24) can be easily disassembled.

Description: BACKGROUND OF THE INVENTION The present invention relates to a press device of the type disclosed, for example, in JP-A-08174094, in accordance with the preamble of claim 1. As shown in Figs. 13 and 14, there is a prior art press device comprising a slide cam base, a slide cam guided by the slide cam base for mounting a machining member such as a punch, an urging member provided between the slide cam base and the slide cam for urging the slide cam, and an actuating cam for abutting the slide cam to guide the same during operation. In Figs. 13 and 14, there is a press device comprising a slide cam base 102 having a quadrangular-section guide member 101 formed at the head thereof, a slide cam 103 guided by the slide cam base 102 for mounting a machining member such as a punch 109, a coil spring 104 provided between the slide cam base 102 and the slide cam 103 for urging the slide cam 103, and an actuating cam 105 for abutting the slide cam 103 to guide the same during operation. The quadrangular-section guide member 101 of the slide cam base 102 is allowed to abut against wear plates 106 of the slide cam and held by guide plates 107, and the guide plates 107 are threadedly fixed to the slide cam 103 with many bolts 108. After a workpiece W has been placed on a supporting member 111 of a lower die 114 in which a die bush 110 is embedded, when an upper die 115 lowers, the wedge-shaped slide cam 103 is moved toward the workpiece W between the slide cam base 102 and the actuating cam 105. Then, when the upper die 115 begins to rise after machining has been completed, the slide cam 103 is moved backward to its original position due to an urging force of the coil spring 104. A stripper plate 112 is urged with a pressurizing rubber 113. In such press devices as described above, a case does not become a large problem where the dimension of the press device in the lateral direction as shown in Fig. 14 (in the horizontal direction in the figure) is short while, particularly where the length of the slide cam 103 in the lateral direction takes a value of, for example, about 300 mm or more, the guide member 101 of the slide cam base 102 is held insufficiently with the wear plate 106 and the guide plate 107 mounted to the slide cam 103, so that a noticeable deflection occurs causing that pressing with a high precision can be hardly performed, and that the machining of the guide member 101, the wear plate 106 and the guide plate 107 requires a longer time, thereby making press devices expensive. Also, for maintenance of the prior art press devices, dismounting of the slide cam 103 from the slide cam base 102 requires that many bolts 108 be loosened in order to remove the guide plate 107, so that maintenance requires a long time. Further, the output force from the coil spring 104 used as an urging force of the slide cam 103 becomes larger depending on the compressed length and when the compressed length of the coil spring 104 is short, the output force is small, so that the coil spring 104 cannot positively move the slide cam 103 back to the original position. A coil spring with an ordinary size is very difficult to have the compressed length of about 150 mm and thus cannot give a stroke of about 150 mm to the slide cam, so that recently in pressing large-sized workpieces for automobile sheet-metal formed parts such as side panels, such coil spring has not satisfied the needs of a long stroke for the slide cam. Still further, in prior art press devices, particularly large-sized press devices, the face pressure on the slide face becomes as large as about 14,7 MPa (150 kg/cm 2 ), so that the wear has been severe and thus wear prevention was insufficiently provided. The slide cam has not been properly guided during moving on the slide cam base, so that the slide cam was not always moved precisely. Further, the slide cam has not been properly guided during moving on the actuating cam, either, so that the slide cam was not always moved precisely for this reason, either. Thus, in view of the above-mentioned circumstances, in order that little deflection occurs when a slide base holds a slide cam to allow a precise pressing, and in order that the time required for machining a slide cam holding member becomes short to provide an inexpensive press device, the present invention provides a press device as defined in claim 1. In the press device of the invention there is little deflection when the slide cam base holds the slide cam to allow pressing with high accuracy. As the slide cam is held by the circular-section guide post, the time required for machining the holding portions of the slide cam can be made short, thereby providing a press device at a lower price. In order to facilitate dismounting of the slide cam from the slide cam base for maintenance, both ends of the guide post are respectively fitted into a hole to hold, a slit leading to one of the holes is engraved, and the slit is threadedly tightened with a bolt to install the guide post. Further, in a preferred embodiment of the present invention, the urging member comprises a gas spring so that the slide cam can positively slide on the slide cam base, thereby making the operation safe. Using a gas spring allows a long stroke to be given to the slide cam base, thereby making the machining of a large-sized workpiece possible. Still further, wear plates may be provided on respective slide faces of both the slide cam and the slide cam base so as to satisfactorily cope with a severe wear of large-sized press devices with heavy weight. Further, in a preferred embodiment of the present invention, slide faces are provided on the sides of both the slide cam and the slide cam base so as to make accurate the movement of the slide cam with respect to the slide cam base. Still further, chevron-shaped slide faces may be provided on the slide faces of the slide cam and the actuating cam so as to eliminate a lateral deflection in the movement of the slide cam with respect to the actuating cam. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view of one specific embodiment of the press device of the present invention as shown with the upper die at the lower dead point position. Fig. 2 is a cross-sectional view taken along the line II-II of Fig. 1. Fig. 3 is a cross-sectional view taken along the line III-III of Fig. 1. Fig. 4 is a cross-sectional view taken along the line IV-IV of Fig. 1. Fig. 5 is a layout view of guide posts, a gas spring and wear plates where a slide cam base is arranged on a lower die and an actuating cam on an upper die, and where the size of the slide cam is 320 mm. Fig. 6 is a layout view of guide posts, a gas spring and wear plates where the size of the slide cam is 380 mm. Fig. 7 is a layout view of guide posts, a gas spring and wear plates where the size of the slide cam is 440 mm. Fig. 8 is a layout view of guide posts, a gas spring and wear plates where the size of the slide cam is 500 mm. Fig. 9 is a layout view of guide posts, a gas spring and wear plates where the size of the slide cam is 600 mm. Fig. 10 is a layout view of guide posts, a gas spring and wear plates where the size of the slide cam is 700 mm. Fig. 11 is a longitudinal sectional view of one specific embodiment of the present invention where the upper die is shown at its upper dead point. Fig. 12 is a longitudinal sectional view of a press device of an example in which a slide cam base is arranged on a lower die and an actuating cam on an upper die. Fig. 13 is a longitudinal sectional view of a prior art press device. Fig. 14 is a cross-sectional view taken along the line XIV of Fig. 13. EMBODIMENTS With reference to specific embodiments shown in attached drawings, the present invention will be explained in detail hereinafter. Fig. 1 is a longitudinal sectional view of one specific embodiment of the present invention where an upper die is at the lower dead point position. Fig. 2 is a cross-sectional view taken along the line II-II of Fig. 1. Fig. 3 is a cross-sectional view taken along the line III-III of Fig. 1. Fig. 4 is a cross-sectional view taken along the line IV-IV of Fig. 1. Figs. 5 through 10 are layout views of guide posts, a gas spring and wear plates according to the size of a slide cam. Fig. 11 is a longitudinal sectional view of the embodiment where the upper die is shown at the upper dead point thereof. Fig. 12 is a longitudinal sectional view of a press device of an example in which a slide cam is arranged on a lower die and an actuating cam on an upper die. The example explained in this embodiment is the one in which a workpiece is punched. As shown in Fig. 1, a supporting member 2 for positioning a workpiece W is fixed to a lower base plate 1 of a lower die 82 with a bolt 3. An actuating cam 4 whose upper face lowers as approaching the supporting member 2 and slants to the right as viewed in the figure is fixed at a place near the supporting member 2 to a lower base plate 1 with a bolt 5. Fixed to an inclined face 6 of the actuating cam 4 is a chevron-shaped guide member 7 with a bolt 8. As shown in Fig. 2, wear plates 9 are fixed to the upper faces of the chevron-shaped guide member 7 with bolts 10, and a wear plate 11 is further fixed to the inclined face 6 with a bolt 12. As shown in Fig. 2, an approximately wedge-shaped slide cam 19 which is engraved with a V-groove 16 on the lower face thereof, and which is provided with a wear plate 17 mounted with a bolt 18 on another section of the lower face, is slidably placed on the actuating cam 4 such that the V-groove 16 abuts against the wear plate 9 of the actuating cam 4, and that the wear plate 17 abuts against the wear plate 11 of the actuating cam 4. On the other hand, a slide cam base 21 whose lower face is inclined reversely to the above-mentioned actuating cam 4 and slants to the right as viewed in Fig. 1 is fixed to an upper base plate 22 of an upper die 81 with bolts 23, and the above-mentioned slide cam 19 is slidably provided on at least one guide post 24 which slant(s) to the right and are (is) installed at the lower end of the slide cam base 21. The slide cam 19 is urged by a gas spring 25 which is contained in the slide cam base 21 and arranged slantingly to the right as seen in Fig. 1. The guide posts 24, as shown in Fig. 1, are installed on supporting plates 28, 29 fixed with bolts 26, 27, respectively, to both the respective sides of the slide cam base 21. Each guide post 24 is fitted into bushes 30, 31 which are coaxially and fixedly press fitted into an inserting hole 42 of a guide post holder 41 of the upper portion of the slide cam 19. One small-diameter end portion of the guide post 24 is fitted into a fitting hole 33 of the supporting plate 28, while the other end portion 34 is fitted into a tightening hole 35 of the supporting plate 29. As shown in Fig. 3, a slit 36 leading from the outer peripheral portion to the tightening hole 35 is provided, i.e. engraved in the supporting plate 29, and a bolt 38 is inserted into a threaded bore extending perpendicularly to the slit 36. Upon tightening of the bolt 38 the gap of the slit is made narrow, and thus the end portion 34 of the guide post 24 located in the tightening hole 35 can be tightened. A circular outer peripheral face or a circular hole can be more precisely machined compared to those of rectangular or other shape. Thus, in the present embodiment, the guide post 24 is made circular in section and the bushes 30,31, the fitting hole 33 and the tightening hole 35 are made circular in bore, so that they can be precisely machined. Due to the fitting relationship between the circular outer peripheral face of the guide post 24 and the circular hole of the bushes 30, 31, a highly accurate fitting is maintained from the axial center to the whole periphery covering 360 degrees. The guide post, if circular in section, may be solid or hollow in section, and, where possible, preferably solid with respect to strength. For the maintenance of the slide cam 19, the actuating cam 4 and the slide cam 19, in some case, must be dismounted from the slide cam base 21. In that case, loosing only one bolt 38 of the supporting plate 29 allows the guide post 24 to be easily pulled out without the necessity to remove a plurality of bolts as in prior art press devices. When a bolt is threadedly attached to a screw hole 39 provided for example axially in the other end portion 34 of the guide post 24, the guide post 24 can be more easily pulled out via the bolt. Fig. 4 shows a configuration in which the slide cam 19 is provided by interposing the guide post 24 and the gas spring 25 in the slide cam base 21. Provided on the underside of the slide cam base 21, at two places in the indicated example, are guide grooves 40 slanting to the right as seen in Fig. 1; the slide cam 19 has protruding guide post holding portions 41 provided on the upper face thereof and slanting to the right as seen in Fig. 1. The guide post holding portions 41 allow the above-mentioned guide grooves 40 to pass. An inserting-through hole 42 slanting to the right as seen in Fig. 1 is bored into each of the guide post holding portions 40, to extend therethrough in the longitudinal direction, and the bushes 30, 31 are coaxially press fitted into the inserting-through hole 42, and then the guide post 24 is internally fitted into the bushes 30, 31. The above-mentioned supporting plate 28 is provided in a manner to cover the above-mentioned guide groove 40 and guide post holding portion 41, and is fixed with a bolt 26 to the slide cam base 21. The gas spring 25 is arranged in a manner to slant to the right as seen in Fig. 1, and is fixedly mounted at the base end thereof to the supporting plate 28; an expansible rod 44 at the head of a cylinder 43 of the gas spring 25 is allowed to abut against a bracket 46 fixed with a bolt 45 to an end slanting to the right on the upper face of the slide cam 19. The slide cam 19, which has a wedge shape, is arranged between the actuating cam 4 and the slide cam base 21, and is urged to move toward the workpiece W on the supporting member 2, thereby machining the workpiece W. Fig. 1 shows the press device at the lower dead point. The slide cam 19 is positioned near the supporting member 2 and at the leftmost side in the figure; the rod 44 of the gas spring 25 is in the most contracted state. When a pressing force acting on the slide cam 19 via the actuating cam 4 and the slide cam base 21 is reduced, an abutting force of the gas spring 25 is exerted on the slide cam 19 to cause the rod 44 to be extended. Fig. 11 shows the press device at the upper dead point in a state in which the rod 44 is extended to a maximum limit. The gas spring 25 contains a gas with a high pressure, for example, that of 14,7 MPa (150 kg/cm 2 ) according to an application within the cylinder 43, so that even when the rod 44 protruding from the cylinder 43 expands or contracts, a substantially constant output, for example that of 14,7 MPa (150 kg/cm 2 ), can be obtained over the entire length of the rod contracting stroke. This is accomplished in such a manner that when the rod 44 contracts to cause one of two tanks contained in the cylinder 43 to be subjected to a pressure, the high-pressure gas flows out of the tank and enters the other tank, thereby providing a substantially constant output over the full stroke of the rod. Thus, unlike a coil spring, with the gas spring 25, a high output is obtained over the full stroke from the start of operation, so that the gas spring allows the slide cam 19 to be returned positively to the original position and thus provides a safe operation. Also, the gas spring 25 allows the slide cam 19 to be moved for a long distance of about 150 mm, so that large-sized workpieces for automobile sheet-metal molded parts such as side panels or the like can be machined. Wear plates 51, 52 are provided on the slide faces of the slide cam base 21 and the slide cam 19, respectively. The wear plates 51 are fixed to the slide cam base 21 with bolts 53, while the wear plates 52 are fixed to the slide cam 19 with bolts 54. Heretofore, in a press device including such a slide cam whose face pressure is about 4,9 to 5,9 MPa (50 to 60 kg/cm 2 ), a wear plate has been provided only either on the slide cam base or on the slide cam, while in the present invention, in order to cope with face pressures of up to about 14,7 MPa (150 kg/cm 2 ) as in a large-sized press device, the wear plates are provided on the slide cam base and on the slide cam, respectively, so that it is sufficient to replace only the worn wear plates. Although the slide cam 19 is guided by the guide post 24 installed on the slide cam base 21 as described above, wear plates 55 are fixed with bolts 56 to both the ends of the slide cam base 21, against which wear plates 55 internal slide faces of side portions 57 of the slide cam 19 are abutted, so that the slide cam 19 can be precisely guided and moved on the slide cam base 21. Further, guide plates 59 are fixed with bolts 60 to the upper faces of both the side portions 57 of the slide cam 19, and the underside of the guide plate 59 is allowed to also abut against a guide face 61 of the slide cam base 21 so that the guide face 61 can be used as an auxiliary guide for the slide cam 19, and at the same time, even if the guide post 24 should break, the slide cam 19 will be held by the slide cam base 21 to ensure a safe operation. Heretofore, in a press device including such a slide cam, even where the dimension of the slide cam in the lateral direction (in the right/left direction in Fig. 4) becomes longer due to the use of large-sized devices, the slide cam has been held only by the guide plates on both the sides and thus remained in a deflected state. In the present embodiment, guide posts are provided on appropriate positions along the lateral dimension so that the slide cam is not deflected. The present invention provides various arrangements of the guide posts, of the gas springs and of the wear plates according to the size of the slide cam as shown in Figs. 5 through 10, provided that the examples of Figs. 5 through 10 are those of a press device in which the slide cam base is arranged on the lower die, while the actuating cam is arranged on the upper die as shown in Fig. 12 described later. In Fig. 5, where the size or the dimension in the lateral direction of the slide cam is 320 mm, the gas spring 25 is arranged at the center. Arranged on both sides of the center are the guide posts 24, and the wear plates 51, 52, 55 also are arranged at respective positions as illustrated. Fig. 6 shows the arrangement of the guide posts 24 and of the wear plates 51, 52, 55 where the size of the slide cam 19 is 380 mm; Fig. 7, where the size is 440 mm; Fig. 8, where the size is 500 mm; Fig. 9, where the size is 600 mm; and Fig. 10, where the size is 700 mm. To make accurate the movement of the slide cam 19 on the actuating cam 4, as shown in Fig. 2, the V-groove 16 of the slide cam 19 is allowed to abut against the wear plate 9 of the chevron-shaped guide member 7 to slidingly guide the slide cam 19, thereby eliminating the lateral deflection of the slide cam 19. To forcedly move the slide cam 19 backward when the upper die 81 rises, a return plate 61 is provided. The return plate 61 is fixed with a bolt 62 to the side of the slide cam 19, and engaged with a guide member 64 fixed with a bolt 63 to the inclined face 6 of the actuating cam 4. An embodiment of the present invention will be explained in an example of punching the workpiece W. As shown in Fig. 1, which shows the press device in a lower dead point position, a spacer 71 is fixed with a bolt 72 to the front face of the slide cam 19 at a position opposite to the supporting member 2 for the workpiece W. A punch 73 for punching the workpiece W is held by a punch plate 74 to protrude therefrom, which punch plate 74 is fixed with a bolt 75 to the spacer 71. The head of the punch 73 is internally fitted into a stripper plate 76, which stripper plate 76 is abutted by a pressurizing rubber 77. On the other hand, a die bush 78 is embedded in a position opposite to the punch 73 on the supporting member 2. On the other hand, Fig. 11 shows a state in which the press device is at the upper dead point position. The operation of the press device will be explained hereinafter. As shown in Fig. 11, the workpiece W is placed on the supporting member 2, and the upper die 81 is allowed to lower. The state shown in Fig. 11 is at the upper dead point, in which the slide cam 19 is slidably provided on the guide post 24 of the slide cam base 21 mounted on the upper base plate 22 of the upper die 81. The slide cam 19 remains abutted against the supporting plate 29. When the upper die 81 lowers from this position, the wear plate 17 and the V-groove 16 of the slide cam 19 abut against the wear plate 11 and the wear plates 9 of the actuating cam 4, and the slide cam 19 moves forward and toward the workpiece W as positioned between the actuating cam 4 and the slide cam base 21 as the upper die 81 lowers, thereby punching the workpiece W by means of the punch 73 and the die bush 78. Fig. 1 shows a state in which the press device when punching by the punch 73 is at the lower dead point. Thereafter, when the upper die 81 rises, the abutting force of the gas spring 25 is transmitted from the bracket 46 to the slide cam 19 which in turn moves backward until it abuts against the supporting plate 29 to stop. Since the return plate 61 is provided on the slide cam 19, in a situation where the slide cam 19 does not move backward due to friction or slight deformations, the return plate 61 engages with the actuating cam 4 to cause the slide cam 19 to be forcedly moved backward. While this embodiment describes a machining example of punching, the present invention can be applied to other machining such as trimming, molding and bending in that the appropriate tool is used as the machining member. Standardizing the size of the slide cam base 21, the slide cam 19 and the actuating cam 4 allows the press device to immediately cope with the machining of workpieces of various sizes. Although the above example has been explained in which the slide cam base 21 is provided on the upper die 81, while the actuating cam 4 is provided on the lower die 82, the slide cam base 21 may be provided on the lower die 82 and the actuating cam 4 on the upper die 81 as shown in Fig. 12. In this example, the slide cam 19 is not suspended from the upper die 81, but provided on the lower die 82. Such an arrangement is considered safe with respect to working. The present invention covers not only a case where the slide cam 19 is provided on the upper die 81, but also that where the slide cam 19 is arranged on the lower die 82.

Claims: A press device comprising a slide cam base (21), a slide cam (19) guided by the slide cam base (21) for mounting a machining member, said slide cam (19) being slidably provided on circular-section guide posts (24) installed on the slide cam base (21), an urging member provided between the slide cam base (21) and the slide cam (19) for urging the slide cam (19), and an actuating cam (4) for abutting the slide cam (19) to be driven, characterized in that the guide posts (24) are installed on supporting plates (28,29) fixed to both respective ends of the slide cam base (21), one small-diameter end portion of the guide posts (24) is fitted into a fitting hole (33) of one (28) of the supporting plates (28,29), the other end portion of the guide posts (24) is fitted into a tightening hole (35) of another one (29) of the supporting plates (28,29), a slit (36) is provided in said another one (29) of the supporting plates (28,29) leading from the periphery to the tightening hole (35) and is threadedly tightenable with a bolt (38) to install the respective guide post (24). A press device as set forth in claim 1, wherein said fitting and tightening holes (33,35) in which said both respective ends of the guide posts (24) are supported by circular holes, and said bolt (38) is inserted into a threaded bore extending perpendicularly to the slit (36) leading to said tightening hole (35). A press device as set forth in claim 1 or 2, wherein the urging member comprises a gas spring (25). A press device as set forth in claim 1, 2 or 3, wherein wear plates are provided on respectively slide faces of both the slide cam (19) and the slide cam base (21). A press device as set forth in claim 1, 2, 3 or 4, wherein slide faces are provided on the sides of both the slide cam (19) and the slide cam base (21). A press device as set forth in claim 1, 2, 3, 4 or 5, wherein chevron-shaped slide faces are provided on the slide faces of both the slide cam (19) and the actuating cam (4).

Inventors: MATSUOKA MITSUO, MATSUOKA, MITSUO
Applicants: UMIX CO LTD, UMIX CO., LTD.
Application year: 1997
Main classification: B21D28
IPC codes: B30B1, B21D28, B21D37