Knockout device for press machine, and press machine

Abstract

To provide a knockout device for a press machine that can measure the knockout load numerically over time with a simple configuration, and a press machine equipped with the same. [Solution] A knockout device 100 for a press machine that pressure-forms a workpiece W with a mold 10, comprising a swinging member 6 that swings in conjunction with the opening and closing operation of the mold, and a knockout pin 7 whose base end 7c is supported by the swinging member and which moves forward and backward in accordance with the swinging of the swinging member, wherein a load measuring means 61 for measuring the knockout load is provided at the connection between the base end of the knockout pin and the swinging member.

Description

Technical Field

[0001] The present invention relates to a knockout device for a press machine.

Background Art

[0002] In a press machine such as a forging machine, it is common to provide a knockout device for pushing out a molded product from a mold.

[0003] For example, Patent Document 1 (Japanese Patent No. ******) discloses a lower knockout device for pushing up a molded product from a lower mold, which includes a cam driven in synchronization with a slide drive shaft of a press machine, a connecting rod that slides vertically in conjunction with the rotation of the cam, a lower lever connected to the lower end of the connecting rod and oscillating about a swing axis, and a knockout lever that oscillates together with the lower lever about a common swing axis.

[0004] In the knockout device of Patent Document 1, the knockout lever oscillates in conjunction with the opening and closing operation of the mold, and a knockout pin engaged with the tip of the knockout lever rises as the knockout lever rotates upward, pushing up the molded product. After pushing up the molded product by this rotation (after primary knockout), an arm oscillated by a hydraulic drive mechanism is engaged with the knockout pin, and the knockout pin is further pushed up by the hydraulic drive mechanism via the arm to push out the molded product from the mold (secondary knockout).

[0005] In the knockout operation of pushing up the mold by the knockout pin, there are cases where the molded product cannot be pushed out due to sticking of the molded product to the mold or the like, and an overload is applied to the knockout device. In such a case, as a means for protecting the knockout device, for example, as shown in Patent Document 2 (Japanese Utility Model Publication No. ******), a countermeasure is taken to provide a stretch bolt (or shear pin) that breaks when a load of a certain level or more is applied.

[0006] Note: The patent numbers in the original text are replaced with ****** in the translation to comply with the privacy requirements. You can replace them with the actual patent numbers if needed.Furthermore, as another means of protecting the knockout device from overload, for example, Patent Document 3 (Japanese Utility Model Publication No. 3-9299) discloses load detection means for detecting the molding load and the bed knockout load, respectively, and stopping the press machine if an overload occurs during molding or bed knockout. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 4079952 [Patent Document 2] Official Gazette No. 61-35317 [Patent Document 3] Japanese Utility Model Publication No. 3-9299 [Overview of the project] [Problems that the invention aims to solve]

[0008] While the apparatus described in Patent Document 2 can determine overload by the fracture of the shear pin, it cannot numerically measure the knockout load, making it difficult to grasp the knockout load over time.

[0009] On the other hand, while Patent Document 3 discloses measuring the knockout load over time using a bed knockout load detection means, it does not disclose the specific arrangement structure of this means.

[0010] The present invention was made to solve the above-mentioned problems, and its objective is to provide a knockout device for a press machine that can measure the knockout load numerically over time with a simple configuration, and a press machine equipped therewith. [Means for solving the problem]

[0011] The present invention relates to a knockout device for a press machine that pressure-forms a workpiece using a die, comprising a swinging member that swings in conjunction with the opening and closing operation of the die, and a knockout pin whose base end is supported by the swinging member and which moves forward and backward in accordance with the swinging of the swinging member. A load measuring means for measuring the knockout load is provided at the connection between the base end of the knockout pin and the swinging member.

[0012] Preferably, a holding means for holding a load measuring means is attached to the oscillating member.

[0013] Preferably, the load measuring means receives the knockout load via a contact member that contacts the base end of the knockout pin.

[0014] Preferably, the cross-sectional shape of the contact surface of the contact member is substantially arc-shaped.

[0015] Preferably, the surfaces of the knockout pin and the contact member that come into contact with each other are formed such that one is convex and the other is concave.

[0016] Furthermore, it is also possible to provide a press machine equipped with the above-mentioned knockout device. [Effects of the Invention]

[0017] According to the present invention, the knockout load can be measured numerically over time with a simple configuration. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic front view showing the general configuration of the lower knockout device according to the embodiment. [Figure 2] This is an enlarged cross-sectional view schematically shown along the line II-II in Figure 1. [Figure 3] This is a front view showing the main parts of the lower knockout device according to the embodiment. [Figure 4](A) is a front view showing the state where the knockout load measuring means is attached to the swinging member, and (B) is a right side view of (A). [Figure 5] It is a plan view of FIG. 4(A). [Figure 6] (A) is an exploded cross-sectional view taken along the VIA-VIA line of FIG. 5, and (B) is an exploded cross-sectional view taken along the VIB-VIB line of FIG. 5. [Figure 7] (A) to (C) are front views sequentially showing the movement of the swinging member in the knockout operation. [Figure 8] (a) to (d) are front views schematically showing the process flow in the transfer press. [Figure 9] It is a perspective view schematically showing a modified example of the liner and the knockout pin.

Embodiments for Carrying Out the Invention

[0019] The embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0020] (Outline of the Knockout Device) Referring to FIGS. 1 to 3, the outline of the knockout device according to the present embodiment will be described. In the present embodiment, a lower knockout device 100 mounted on a press for pressure-molding a workpiece with a mold (including an upper mold and a lower mold 10) will be described. In FIG. 1, the illustration of the upper mold, the upper knockout device, etc. is omitted. In FIG. 1 and the like, the vertical direction is indicated by the symbol Z, the left-right direction of the lower knockout device 100 is indicated by the symbol X, and the depth direction is indicated by the symbol Y.

[0021] As shown in FIG. 1, the lower knockout device 100 includes a swinging member 6 that swings in conjunction with the opening and closing operation of the mold (upper mold), and a knockout pin 7 whose base end portion (lower end portion) is supported by the swinging member 6 and advances and retreats in accordance with the swing of the swinging member 6. In the present embodiment, the swinging member 6 is a knockout lever 6 and constitutes a part of a mechanical drive mechanism A described below.

[0022] (Regarding mechanical drive mechanisms) The mechanical drive mechanism A includes a cam 1 driven in synchronization with the slide drive shaft (not shown) of the press machine, an upper lever 3 having a roller 2 that engages with its outer circumference and one end 3a supported by a pivot, and a connecting rod 4 extending in the vertical direction that is rotatably connected to the other end 3b of the upper lever 3 via a pin. The mechanical drive mechanism A also includes a pivot shaft 6a arranged horizontally (in the depth direction) below the bolster 8, and a lower lever 5 supported at one end of the pivot shaft 6a that is rotatably supported in the vertical direction. The tip of the lower lever 5 (the part that rotates vertically) and the lower part of the connecting rod 4 are rotatably connected via a pin.

[0023] The pivot shaft 6a is provided with a knockout lever (an example of a pivoting member) 6 that pivots integrally with the lower lever 5 from the middle of its axial direction toward the other end. As a result, the knockout lever 6 pivots vertically in conjunction with the raising and lowering of the upper mold (opening and closing operation of the mold). As shown in Figure 3, the tip portion 6e (the portion that rotates vertically) of this knockout lever 6 supports the lower end portion 7c of the knockout pin 7. In this embodiment, multiple knockout pins 7 are provided in the depth direction (see Figure 2), and there are as many knockout levers 6 as there are knockout pins 7.

[0024] As shown in Figure 1, the connecting rod 4 and the lower lever 5 may be connected via a hydraulic cylinder 11 for preventing overload. Furthermore, an air cylinder 12 may be attached to the lower lever 5 to bias it downwards.

[0025] (Regarding knockout pins) The knockout pin 7 is a vertically extending rod-shaped member that moves up and down as the knockout lever 6 swings vertically. As will be described later, in this embodiment, similar to Patent Document 1, the knockout pin 7 may be divided into an upper knockout pin 7a and a lower knockout pin 7b whose lower end engages with the knockout lever 6.

[0026] As shown in Figure 1, the knockout pin 7 is provided to pass through the die holder 9 and bolster 8 that support the lower mold 10 and is vertically movable along the guide 18, and pushes up the molded product W inside the lower mold 10 of the press machine in response to the upward rotation of the knockout lever 6.

[0027] As shown in Figure 3, in this embodiment, a load measuring means 61 for measuring the knockout load (the load applied to the knockout lever 6 via the knockout pin 7) is attached to the connection between the lower end portion 7c of the knockout pin 7 and the knockout lever 6. The mounting structure of the load measuring means 61 will be described below.

[0028] (Regarding the mounting structure of the load measuring device) As shown in Figures 4 and 6, the load measuring means 61 is attached to the tip 6e of the knockout lever 6 while being held in a case 60 (an example of a holding means). In this embodiment, a diaphragm-type load cell 61 is used as an example of the load measuring means 61.

[0029] The case 60 is formed in a substantially U-shape when viewed in the left-right direction (X direction) of the lower knockout device 100, and has a pair of vertical walls 60a, 60a on the left and right sides. The load cell 61 is positioned and held between the two vertical walls 60a. As shown in Figure 6, the load cell 61 is fixed to the bottom 60c of the case 60 by fixing bolts 610. A shim tape 61a for position adjustment may be attached to the bottom surface of the load cell 61.

[0030] The case 60 is detachably attached to the tip 6e of the knockout lever 6. Specifically, a recess is formed on the upper end surface of the tip 6e, and the lower end of the case 60 fits into this recess. A screw hole is provided on the lower end surface of the case 60, and the case 60 is attached by screwing a detachable bolt 600, which passes through the tip 6e, into this screw hole.

[0031] A liner 62 is placed on the load cell 61. As will be described later, the liner 62 is a contact member that contacts the base end (lower end 7c) of the knockout pin 7 and plays the role of transmitting the knockout load to the load cell 61. The liner 62 is placed so that its bottom surface contacts the load button 61b located in the center of the upper surface of the load cell 61. The liner 62 is formed in a substantially cylindrical shape that extends vertically, and its upper surface 62a is formed to be substantially arc-shaped when viewed in the X direction, with a flange portion 62b that protrudes outward at its lower end.

[0032] A liner guide 63, which fits onto the liner 62 from above, is fixed to the case 60 via fixing bolts 630. The liner guide 63 has a through hole 63a that runs vertically through its central portion, and is fixed to the case 60 with the liner 62 inserted through this through hole 63a.

[0033] The through-hole 63a has a large diameter portion at its lower end, and the flange portion 62b of the liner 62 engages with this large diameter portion, preventing the liner 62 from coming out upward. An O-ring 64 may be attached to the peripheral wall at the upper end of the through-hole 63a to seal the gap with the liner 62.

[0034] The liner guide 63 is fixed to the vertical wall portion 60a of the case 60 by fixing bolts 630. In this way, the load cell 61 is sandwiched from above and below by the case 60 and the liner 62 and liner guide 63.

[0035] As shown in Figure 3, the load cell 61 is positioned at the connection point between the lower end 7c of the knockout pin 7 and the tip 6e of the knockout lever 6. The knockout load can be measured over time by the contact between the lower end 7c and the upper surface 62a (Figure 4) of the liner 62. Since the upper surface 62a of the liner 62 is formed in a substantially arc shape when viewed in the X direction, it always makes proper contact with the lower end 7c of the knockout pin 7.

[0036] As shown in Figure 4(B), the load cell 61 is electrically connected to an external device P via code 61c, and the data measured by the load cell 61 is recorded chronologically in the memory of the device P. The external device P is a computer including a processor and memory.

[0037] As shown in Figures 4 and 6, a dust cover 66 may be fitted over the case 60 and liner guide 63 from above. This protects the load cell 61 from external elements. Alternatively, a dust sheet 65 may be provided between the dust cover 66 and the liner guide 63 as an additional protective measure.

[0038] The dustproof sheet 65 and the dustproof cover 66 each have vertically penetrating openings 65a and 66a in the center of their upper surfaces, and the upper part of the liner 62 is exposed through both openings 65a and 66a. The dustproof cover 66 is fixed to the liner guide 63 by fixing bolts 660 with its side plate portion 66b in contact with the vertical wall portion 60a of the case 60.

[0039] As shown in Figures 4 and 5, the upper part of the liner 62, including the upper surface 62a, is exposed to the outer space (in Figure 4, the dust cover 66 is shown by a dashed line). The upper surface 62a includes a contact surface that contacts the flat (horizontal) bottom surface of the lower end 7c of the knockout pin 7. The knockout operation will now be described with reference to Figures 7 and 8.

[0040] (Regarding the knockout action) Figures 7(A) to 7(C) show how the knockout lever 6 rotates upward in conjunction with the movement of the upper and lower molds (not shown) to open (upper mold moves upward) after the upper and lower molds have been closed and the workpiece has been pressure-molded, that is, the movement of the slide from its bottom dead center upward.

[0041] Figure 7(A) shows the standby state before the tip 6e of the knockout lever 6 begins to rotate upward from its lowest position. In this state, as shown in Figure 8(a), the molded product W is fitted into the mold frame of the lower mold 10.

[0042] Figure 7(B) shows the state in which the knockout lever 6 is horizontal during the knockout operation. As the knockout lever 6 rotates, the knockout pin 7 rises. In this state, as shown in Figure 8(b), the molded product W, which is pushed up by the knockout pin 7, is pushed upward along the mold frame.

[0043] Figure 7(C) shows the state where the tip 6e of the knockout lever 6 has rotated to its highest point and the knockout pin 7 has risen further. In this state, as shown in Figure 8(c), the rising of the knockout pin 7 causes the molded product W to be completely ejected from the lower mold 10.

[0044] During the knockout operation, the upper surface 62a of the liner 62, which contacts the flat bottom surface of the knockout pin 7, is approximately arc-shaped. Therefore, the knockout load can be measured over time by the load cell 61 regardless of the angle of the knockout lever 6. The rotation angle of the knockout lever 6 is, for example, about 20°.

[0045] (Advantages of this embodiment) By providing a load cell 61 at the tip 6e of the knockout lever 6, the knockout load can be measured over time. This makes it possible to reliably detect overloads on the lower knockout device 100. For example, by monitoring the changes in the knockout load with an external device P and stopping the press machine when an overload occurs, it is possible to avoid damage to the knockout lever, mold, etc.

[0046] Furthermore, since the load changes depending on the shape and material of the mold and billet (product material), understanding the difference between the measured knockout load and the design value is effective for designing the mold and billet shapes.

[0047] Furthermore, in this embodiment, the upper surface 62a of the liner 62, which is the contact surface with the bottom surface of the lower end 7c of the knockout pin 7, is formed in a substantially arc shape, so that it makes smooth contact with the lower end 7c during the knockout operation. As a result, the transition of the knockout load can be measured continuously, and the measurement accuracy is improved.

[0048] Furthermore, as shown in Figure 6, the case 60 is attached to the tip 6e of the knockout lever 6 by a detachable bolt 600. Therefore, the case 60 holding the load cell 61 can be easily attached to and detached from the knockout lever 6 simply by tightening / loosening the detachable bolt 600. Since the knockout lever 6 does not need to be disassembled, inspection and repair of the load cell 61 are less time-consuming.

[0049] Furthermore, as shown in Figure 6, the liner 62 has a simple structure in which it is fixed to the case 60 together with the liner guide 63 by fixing bolts 630, making it easy to replace the liner 62 with another liner when it becomes worn or damaged.

[0050] (others) 1. In this embodiment, the load measuring means 61 is attached to the tip 6e of the knockout lever 6, but it may be attached to the lower end (base end) 7c of the knockout pin 7 instead. In other words, the load measuring means only needs to be provided at the connection between the base end of the knockout pin and the knockout lever (rocking member). Alternatively, the load measuring means 61 may be provided at the connection between the base end of the knockout pin and the rocking member of the upper knockout device.

[0051] 2. The load cell mentioned as an example of the load measuring means 61 may be either a strain gauge type or a piezoelectric type. Furthermore, the load measuring means is not limited to a load cell, and other means, such as a force gauge, may be applied.

[0052] 3. The knockout device of this embodiment may also be used in a transfer press. Specifically, in a transfer press in which a different lower die of a mold is arranged for each of the multiple knockout pins 7 (see Figure 2) provided horizontally, and the workpiece is transported from upstream to downstream, a load measuring means 61 may be provided for each knockout lever that pushes up each knockout pin 7. This allows for the measurement of the knockout load for each die. In a transfer press, the workpiece W pushed up by the knockout pins 7 is held by the fingers F of a transfer feeder and transported to another lower die downstream, as shown in Figures 8(c) and (d).

[0053] 4. The lower knockout device 100 may be equipped with a hydraulic drive mechanism B similar to that described in Patent Document 1, as shown in Figures 1 and 3. In this case, the knockout pin 7 is divided into an upper knockout pin 7a and a lower knockout pin 7b, and moves up and down together in response to the swinging of the knockout lever 6. The hydraulic drive mechanism B has a structure in which a swing arm 13, operated by a hydraulic cylinder 14 having a rod 14a and an air cylinder 15 having a rod 15a, rotates around a swing axis 13a, raising only the upper knockout pin 7a. The hydraulic drive mechanism B may be operated auxiliaryly, for example, when the molded product W does not come off the lower mold 10 properly by the upward thrusting of the knockout pin 7 by the knockout lever 6 alone.

[0054] (modified version) In this embodiment, the upper surface 62a of the liner 62 is formed to be substantially arc-shaped when viewed in the X direction. Alternatively, the upper surface 62a may be formed flat, and the bottom surface of the lower end portion 7c of the knockout pin 7 may be formed to be convex (hemispherical) toward downward.

[0055] As another modification, as shown in Figure 9, the surfaces of the knockout pin 7 and the contact member (liner 62) that come into contact with each other may be formed with one side being convex and the other side being concave. The lower end surface 7d of the base end 7c of the knockout pin 7 is formed in a convex (hemispherical) shape that is approximately arc-shaped, while a concave (hemispherical) recess 62c is formed in the central part of the upper surface 62a of the liner 62. During the knockout operation, the convex lower end surface 7d and the concave recess 62c come into contact, so that the knockout pin 7 is stably pushed up. This modification may also be applied in combination with a hydraulic drive mechanism B.

[0056] Although embodiments of this invention have been described above with reference to the drawings, this invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as this invention, or within the equivalent scope. [Explanation of Symbols]

[0057] 1 Cam, 2 Roller, 3 Upper lever, 4 Connecting rod, 5 Lower lever, 6 Knockout lever (rocking member), 6a, 13a Rocking shaft, 7 Knockout pin, 7a Upper knockout pin, 7b Lower knockout pin, 8 Bolster, 9 Die holder, 10 Lower mold, 13 Rocking arm, 60 Case (holding means), 61 Load cell (load measuring means), 62 Liner, 63 Liner guide, 64 O-ring, 65 Dustproof sheet, 66 Dustproof cover, 100 Lower knockout device, F Finger, W Workpiece.

Claims

1. A knockout device for a press machine that pressure-forms a workpiece using a mold, A swinging member that swings in conjunction with the opening and closing operation of the mold, The rocking member has a base end supported by the rocking member and comprises a knockout pin that moves forward and backward in accordance with the rocking of the rocking member, A knockout device for a press machine, characterized in that a load measuring means for measuring the knockout load is provided at the connection between the base end of the knockout pin and the oscillating member.

2. The knockout device for a press machine according to claim 1, wherein a holding means for holding the load measuring means is attached to the oscillating member.

3. The knockout device for a press machine according to claim 1, wherein the load measuring means receives the knockout load via a contact member that contacts the base end of the knockout pin.

4. The knockout device for a press machine according to claim 3, wherein the cross-sectional shape of the contact surface of the abutting member is substantially arc-shaped.

5. The knockout device for a press machine according to claim 3, wherein one of the surfaces of the knockout pin and the contact member that come into contact with each other is formed in a convex shape and the other is formed in a concave shape.

6. A press machine equipped with a knockout device according to any one of claims 1 to 5.

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