Press die with energising device

Abstract: Improvements have been made in operatability by enabling easy attaching/detaching of an energizing body for energizing a press member while being attached to a press die. For this purpose, it has been devised for an energizing device for a press die that is comprised with an energizing body for energizing by being disposed between two members to abut against both surfaces thereof for energizing, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body.

Description: BACKGROUND OF THE INVENTION The present invention relates to a press die with an energizing device, and more particularly, to one with an energizing device that can be easily attached and detached and that is provided to be sufficiently safe. A press die according to the pre-characterising part of claim 1 is disclosed in document EP-A-0922509. A further conventional a press die is shown in Fig. 7 and Fig. 8. In such a press die, a work W is mounted on a supporting portion 102 of a lower die 101 such that a hole 105 may be formed in a piercing manner on a lateral surface of the work W by means of a punch 104 that is horizontally arranged with respect to a passive cam 103 performing sliding movements in lateral direction, wherein the passive cam 103 is driven by an active cam 107 of an upper die 106. In Fig. 7, the mold assumes a condition at a dead bottom center, and upon completion of the hole forming process, the upper die 106 is raised, and in the absence of pressuring force applied by the active cam 107, the passive cam 103 is retracted through energizing force of a coil spring 108 that is provided at a lower portion of the cam until it abuts against a terminating surface 110 of a wall body 109 to be terminated. Here, the coil spring 108 which functions to retract the passive cam 103 is arranged in that it is outwardly fitted to a guide pin 112 that is formed to be extruded in a horizontal condition by being screwed to a rising wall 111 such that one end surface abuts against the rising wall 111, and the other end surface is made to abut against a supporting plate 113 wherein this supporting plate 113 is fixed to the passive cam 103 by means of a bolt 114. The supporting plate 113 is carved with a groove 115 that is open in a downward direction such that the guide pin 112 may be taken out at the time of performing maintenance or inspection. Due to the groove 115 carved into the supporting plate 113, a part of the coil spring 108 abutting against the plate is lacking such that fit of the coil spring 108 with respect to the supporting plate 113 becomes instable. Consequently, the coil spring 108 can no longer be disposed in a horizontal condition to result in cases in which the coil spring 108 abuts against an outer periphery of the guide pin 112 such that the guide pin 112 is worn or the coil spring 108 is deformed or seized so that the energizing device may not be completely actuated. It is desired to provide a press die which is capable of eliminating the above-mentioned drawbacks such as occurrence of deformation or seizing of the coil spring or damages in the guide pin, and which presents favorable operatability by enabling the coil spring or the guide pin to be easily attached or detached at the time of performing maintenance or inspection without the necessity of detaching the press die from the press machine while such operations can be performed in a safe manner. In order to meet these objectives, a press die is provided which comprises the features of claim 1. Advantageous further developments of the invention are defined in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] This is a longitudinal sectional view showing a condition at a bottom dead center according to one concrete embodiment of a press die according to the present invention. [Fig. 2] This is a longitudinal sectional view showing a condition of Fig. 1 at a top dead center. [Fig. 3] This is a longitudinal sectional view showing a condition at a bottom dead center according to another embodiment of a press die according to the present invention employing urethane rubber as an energizing body. [Fig. 4] This is a longitudinal sectional view showing a condition at a bottom dead center according to still another embodiment of a press die according to the present invention employing a gas spring as an energizing body. [Fig. 5] This is a longitudinal sectional view showing the energizing device for a press die that is provided with a freely attachable/detachable safety plate at a slide cam opposing a plug. [Fig. 6] This is a longitudinal sectional view showing a press die that is provided with a freely attachable/detachable safety plate at a portion of a wall body blocking a taking-out hole. [Fig. 7] This is a longitudinal sectional view showing a conventional press die at a bottom dead center. [Fig. 8] This is a view showing main parts of the press die of Fig. 7 seen from a direction of arrow VIII. EMBODIMENT Concrete embodiments of the present invention as shown in the accompanying drawings will now be explained in details herein below. Fig. 1 shows a press die at a bottom dead center wherein a work W is, for instance, formed with a negative angle. In the drawing, a lower die 1 is comprised with a supporting portion 2 for the work W on a leftward upper side when seen in the drawing, and a columnar body 4 is provided below the supporting portion in a freely rotating manner which is carved with an intruding forming portion 5 located above a center C of the columnar body 4. A slide cam 6 is provided at a horizontally arranged guide pin 7 in a freely sliding manner, and negative angle forming is performed through an intruding forming portion 8 that is formed at a leftward upper side of the slide cam 6 and the intruding forming portion 5 of the columnar body 4. An upper die 9 is provided with an active cam 10 that descends to drive the sliding cam 6. It should be noted that reference number 11 denotes a pad. Upon completion of negative angle forming, the upper die 9 is raised as shown in Fig. 2. For retracting the slide cam 6 upon rising of the upper die 9, a coil spring 12 is provided at a lower portion of the slide cam 6. The guide pin 7 is horizontally arranged between a rising wall 13 of the lower die 1 and a wall body 14, and the slide cam 6 performs sliding movements through this guide pin 7. In case driving force applied to the slide cam 6 is released upon rising of the active cam 10, the slide cam 6 is energized by the energizing force of the coil spring 12 that is provided at the lower portion of the slide cam 6 until the slide cam 6 reaches a terminating surface 15 of the wall body 14. The coil spring 12 is attached to an attaching hole 16 that is horizontally pierced through a lower portion of the slide cam 6 such that one end surface of the spring abuts against a wall surface of the rising wall 13 and the other end surface is attached by being abutted against a plug 17 which assumes an outer diameter that is larger than an outer diameter of the coil spring 12. An end surface on an opposite side of the plug 17 at which the coil spring 12 abuts is formed with a concave hexagonal hole 18 for taking-out, and a taking-out hole 19 is piercingly formed on the wall body 14 opposing the hexagonal hole 18 of the plug 17 having a dimension that is larger than the outer diameter of the plug 17. For taking out the coil spring 12 or the plug 17, a tip of a rotating rod (not shown), this tip being formed to assume a hexagonal shape, is inserted from the taking-out hole 19 of the wall body 14 into the hexagonal hole 18 of the plug 17 and is rotated for detaching the plug 17 whereupon the coil spring 12 can be taken out. At the time of attaching the coil spring 12, the rod is again inserted from the taking-out hole 19 of the wall body 14 into an attaching hole 16 of the slide cam 6 whereupon the plug 17 is inserted from the taking-out hole 19 of the wall body 14 and screwed thereat to abut against the end surface of the coil spring 12. While the above explanation is based on an example in which the energizing body of the energizing device for a press die is a coil spring, the energizing body is not limited to a coil spring but may also be of urethane rubber or cushion rubber, and it may further be a gas spring or any other energizing body. Fig. 3 shows an example in which the energizing body is urethane rubber 31, and Fig. 4 an example in which the energizing body is a gas spring 32. The gas spring accumulates in a cylinder 33 thereof high-pressure gas, e.g. high-pressure gas of 150 kg/cm 2 , depending to various purposes, and even though a rod 34 extruding from the cylinder 33 is expanded or retracted, a substantially constant output of, e.g. 150 kg/cm 2 , can be obtained during the entire length of the expanding and retracting process of the rod. The substantially constant output can be achieved during the entire process of the rod 34 through two tanks that are incorporated within the cylinder 33 wherein in case the rod 34 is retracted and pressure is applied to one tank, high-pressure gas is made to flow out from this tank to flow into the other tank. In this manner, the gas spring 32 is capable of performing high output from the start of actuation and during the entire process unlike a case with the coil spring 12 whereby the slide cam 6 can be reliably returned to ensure safety. Further, by the use of the gas spring 32, the slide cam 6 is enabled to move a distance as long as 150mm, and processing of a large-sized work of thin plate is also enabled. Due to the provision of the taking-out hole 19 at the wall body 14 at a portion opposing the plug and the energizing body, it may happen that the plug 17 or the energizing body or the plug 17 and the energizing body may jump out through the taking-out hole 19 and to hit against an operator in case the plug 17 comes off owing to oscillation during usage owing to the fact that the energizing body is highly pressurized. In order to prevent this from happening to improve operatability and to secure safety, a safety plate 34 may be attached at a position opposing the plug 17 of the slide cam 6 as shown in Fig. 5 or a safety plate 35 at the wall body 14 as shown in Fig. 6. As explained so far, the energizing device of a press die according to the present invention has been devised to comprise an energizing body for energizing being disposed between two members to abut against both surfaces thereof, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body. With this arrangement, easy attaching/detaching of the energizing body for energizing a press member can be performed while maintaining a condition in which the energizing body is attached to a press die so that operatability is improved. The energizing device of a press die of the present invention is particularly arranged in that the plug is screwed to the one member to be attached to the one member. The energizing device of a press die of the present invention is particularly arranged in that a taking-out hole is formed in a concave manner on a surface of the plug opposite to a surface at which the energizing body abuts. Moreover, the energizing device of a press die according to the present invention has been devised to be an energizing device that is comprised with an energizing body for energizing by being disposed between two members to abut against both surfaces thereof, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body, and wherein a taking-out hole of an inner diameter that is larger than the outer diameter of the plug is pierced to a wall body that is disposed as to oppose the plug. Further, the energizing device of a press die according to the present invention has been devised to be an energizing device that is comprised with an energizing body for energizing by being disposed between two members to abut against both surfaces thereof, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body, and wherein the device is further comprised with a safety device for preventing jumping-out of the plug and/or the energizing body. With this arrangement, easy attaching/detaching of the energizing body for energizing a press member can be performed while maintaining a condition in which it is attached to a press die so that operatability is improved. Moreover, the energizing device of a press die according to the present invention is particularly an energizing device that is comprised with an energizing body for energizing by being disposed between two members to abut against both surfaces thereof, wherein one of the members is provided with a plug of an outer diameter that is larger than an outer diameter of the energizing body and abutting against an end surface of the energizing body, wherein a taking-out hole of an inner diameter that is larger than the outer diameter of the plug is pierced to a wall body that is disposed as to oppose the plug, and wherein the device is further comprised with a safety device for preventing jumping-out of the plug and/or the energizing body. Moreover, the energizing device of a press die according to the present invention is particularly arranged in that the safety device is a safety plate that is provided in a freely attachable/detachable manner as to oppose the plug of the one member. Further, the energizing device of a press die according to the present invention is particularly arranged in that the safety device is a safety plate that is provided in a freely attachable/detachable manner as to oppose the plug of the wall body.

Claims: A press die of the type comprising an active cam (10) and a sliding cam (6), said sliding cam (6) being arranged so as to be driven by said active cam (10) to slide along a guide pin (7) arranged between two spaced apart wall bodies (13,14); and an energizing body (12;31;32) arranged between one of said wall bodies (13,14) and said slide cam (6) for retracting said slide cam (6), characterised in that said energizing body (12;31;32) is arranged in a hole (16) provided in said slide cam (6) such that one end of said energizing body (12;31;32) abuts against said one of said wall bodies (13,14) and that the other end thereof abuts against a plug (17) closing an end of said hole (16) opposed to the other one of said wall bodies (13,14), said plug (17) having an outer diameter which is larger than the outer diameter of said energizing body (12;31;32), and in that a hole (19) is formed through said other one of said wall bodies (13,14) at a position opposed to said plug (17) and with a dimension that is larger than the outer diameter of said plug (17) so as to allow removal of said plug (17) from said slide cam (6) through said hole (19). The press die according to claim 1, wherein a taking-out hole (18) is formed in a surface of said plug (17) opposed to said hole (19) in said other one of the wall bodies (13,14). The press die according to claim 1 or 2, wherein said plug (17) is screwed into said end of said hole (16) opposed to the other one of said wall bodies (13,14). The press die according to any one of claims 1 to 3, wherein a safety device (34;35) for preventing jumping-out of said plug (17) and/or of said energizing body (12;31;32). The press die according to claim 4, wherein said safety device is a safety plate (34) that is releasably attached to said slide cam (6) so as to oppose said plug (17). The press die according to claim 4, wherein said safety device is a safety plate (35) that is releasably attached to said other one of the wall bodies (13,14) so as to oppose said plug (17).

Inventors: MATSUOKA MITSUO, MATSUOKA, MITSUO
Applicants: UMIX CO LTD, UMIX CO., LTD.
Application year: 1999
Main classification: B21D28
IPC codes: F16F1, B21D37, B21D5, B21D28, B30B1