JPS6195724A - Press brake - Google Patents

Abstract

PURPOSE:To improve the accuracy of synchronizing and that of stopping at an upper limit, by providing a pair of swiveling links swiveled back and forth in a fixed range by actuating a hydraulic cylinder and disposing a pair of right and left ram-lifting beams moving in connection with the links. CONSTITUTION:A pair of right and left swiveling links 25 are pivotally supported by pins 26 through their one ends at the upper parts of upper press pads 3, and are swiveled back and forth within a fixed range through the actuations of hydraulic cylinders 27 attached to pins 27a. A beam 18 for moving vertically a ram 6 is connected to the other end of link 25 by a pin 28a to hold the ram 6 at its lower limit position when the link 25 locates at the position of backside swiveling limit, and to raise the ram 6 to its upper limit position when the link 25 locates at the position of its frontside swiveling limit. By this mechanism, the accuracy of stopping at the upper limit and that of synchronizing higher in accuracy than conventional ones are obtained becaused a link motion mechanism is disposed between the cylinder 27 and the ram 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a ram upward pressure type press brake, which is a type of press for bending thin steel plates and the like.

[Technical background of the invention and its problems]

Conventional press brakes are constructed so that a hydraulic cylinder attached to a housing frame directly moves a ram up and down under hydraulic control to bend a thin steel plate.

However, with this type of press brake, it is difficult to obtain accurate upper limit (or lower limit) stopping accuracy and synchronization accuracy.

Therefore, the present applicant has already filed a patent application for a press brake that solves the above conventional problems as an invention related to Japanese Patent Application No. 59-156886.

The press brake of this prior invention incorporates a link motion mechanism between the hydraulic cylinder and the ram.
Accurate and reliable lower limit stopping accuracy and synchronization accuracy can be obtained, but since this is a press brake that bends a thin steel plate by applying downward pressure from the ram, the beam-ram pin branch gap and However, there was a problem in that a balance spring was required to absorb the backlash of the slide adjustment screw.

[Means for solving problems]

This invention achieves the same object as the earlier invention described above, and is a press brake of the ram upward pressurization type that eliminates the need for the balance spring of the earlier invention, and the upper mold is attached between a pair of left and right frames. A press machine body with an upper press pedestal installed thereon, and a front vertical guide part having a horizontal length to be horizontally suspended between both side frames of this press machine body and located below the upper press pedestal of the both sides frames. A ram for raising and lowering the lower mold that is slidably guided so that it can move up and down, and a hydraulic cylinder that is pin-supported at one end at the upper position of the press pedestal on both sides of the frame from the backward rotation limit position to the forward rotation limit position. a pair of left and right rotation links that are rotated back and forth within a certain range by It is comprised of a pair of left and right ram elevating beams that hold the ram at the lower limit position when it is at the rotation limit position and raise the ram to the upper limit position when the rotation link is rotated to the forward rotation limit position. It is characterized by this.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In the figure, 1 is a press machine body in which an upper press pedestal 3 for attaching an upper mold is horizontally installed between a pair of left and right side frames 2 and 2. As shown in FIGS. 2 and 3, a vertical guide portion 4.5 projecting outward is provided at the vertical front edge portion of the frames 2, 2 on both sides of the main body located below the upper press pedestal 3. There is.

Reference numeral 6 denotes the front vertical guide portions 4 and 5 of the both side frames 2.2.
A ram for raising and lowering the lower mold that is slidably guided so that it can move up and down.
This ram 6 has a horizontal length that is horizontally suspended between the frames 2, 2, and the machine body frames 2, 2 are attached to both left and right ends of the ram 6.
As shown in FIGS. 2 and 3, the vertical guide portion 4.degree. 5 is provided with slide gibs 6a and 6b that are slidably engaged, and a vertically elongated hole 7.8 that opens on the front and rear surfaces.

Reference numeral 10 denotes a ram lifting/lowering stroke adjusting device installed on the ram 6, and this adjusting device 10 is connected to a pair of left and right slide blocks 11.11 (this one) which are movably inserted into vertically elongated holes 7.8 at the left and right ends of the ram. The lower end of a beam 18.18 (described later is supported by a pin on the slide block), a worm 13 screwed into an upwardly protruding screw 12 of this slide block 11.11, and a worm gear 14 meshed with the worm.
Worm reducer built in a box to which the ram is fixed 15.
15, and an electric motor 17 that reversibly rotates the worm gear 14 of the worm reducer via a rotation transmission system 16.

Reference numerals 25 and 25 denote a pair of left and right rotation links having one end pivoted at the upper position of the upper press holder 3 of the frame 2.2 with a pin 26;
．． By the operation of a hydraulic cylinder 27.27, which is attached to the outer side of 2 so as to be movable up and down with a pin 27a, the position moves from the backward rotation limit position shown in FIG. 1 (A>) to the forward rotation limit position shown in FIG. 1 (B). It is designed to be rotated back and forth within a certain range until it reaches the desired position.

Reference numerals 18 and 18 refer to a pair of left and right rams for lifting and lowering, the upper end of which is connected to the other end of the rotation link 25.25 with a pin 28a, and the lower end of which is pivoted to the left and right end slide blocks 11.11 of the ram 6 with a pin 28b. This beam 18°18 holds the ram 6 at the lower limit position as shown in the left half view of FIG. 1 and FIG. 1(A) when the rotation link 25.25 is at the rear rotation limit position. Moreover, when the rotation link 25.25 is rotated to the forward rotation limit position, it serves to raise the ram 6 to the upper limit position as shown in the left half of FIG. 1 and FIG. 1(B). The vertical guide portions 4.5 are disposed on opposite inner surfaces of the both-side frames 2.2 so as to partially protrude from the vertical guide portions 4.5 on the front surface of the frames.

Furthermore, an arc elongated hole 29 for defining a link rotation range is provided in the upper part of the frame 2.2, into which a pin 28a connecting the upper end of the beam 18 and the other end of the rotation link 25 is inserted. The coupling pin 28 protrudes from this arcuate long hole 29
A piston rod end of a hydraulic cylinder 27.27 is connected to the pin end of a.

Number 30 shown in Figure 1 (B) Press pedestal 3 on the upper part of the machine body
The upper mold 31 is attached to the lower side, and the lower mold 31 is for upward pressurization and is attached to the upper end of the ram 6.
．． The thin steel plate is bent by the press action at the upper limit of the ram lift of 31.

In the above embodiment, the slide block 11.11 is fitted into the vertically elongated hole 7.8 of the ram 6, and when the ram is at its upper limit, the pin branches at the upper and lower ends of the beam and the frame pin branches of the rotation link 25 are centered on the ram. As shown in FIG. 1(B), the beam 18.1 is located on a vertical axis passing through the
It is also possible to adopt a configuration in which the lower ends of the rams 8 are directly supported by pins on the left and right ends of the rams 6.

In the press brake having the above configuration, the pair of left and right rotation links 25.25 are moved from the backward rotation limit position shown in FIG. 1(A) to the rearward rotation limit position shown in FIG.
) When it is rotated to the forward rotation limit position shown in ), this link motion causes the pair of left and right beams 18.18 to rise while rotating forward using the lower end pin support (position of pin 28b) as a fulcrum. By this beam operation, the ram 6 is guided by the vertical guide parts 4 and 5 of the frames 2.2 on both sides of the main body and ascends, and the lower die 31 attached to the upper end of this ram and the upper die attached to the upper press pedestal 3. Press bending of a thin steel plate is performed using the die 30.

The movement of the hydraulic cylinder 27, 27 in this case and the ram 6
The movement of the hydraulic cylinder 27.2 is such that the ram movement distance with respect to a constant movement distance of the hydraulic cylinder 27.27 over time becomes smaller as the ram reaches the upper limit.
7, the lower mold 31 attached to the ram 6
The ram speed is high until it reaches the plate bending region (workpiece), and the pressurization speed is slow during the bending process when the workpiece is bent.

FIG. 5 is an operational explanatory diagram schematically showing the above-mentioned operational relationship, in which the position of the link-beam coupling pin 28a operated by the hydraulic cylinder 27 is 2 cylinder strokes from the link backward rotation limit position. 1 position sl, 3/4 of the same
, the position of the lower end pin 28b of the beam 18 is, for example, 11/15 from the pin lower limit position.
Raised position S1', 13/15 raised position S2-.
. . . indicates an operating state in which the moving distance becomes smaller and the speed becomes slower as the ram approaches the ram lift limit.

〔Effect of the invention〕

Since the play brake of the present invention has the above-described structure, by incorporating a link motion gate between the hydraulic cylinder and the ram, as in the prior invention described above, an accurate and reliable upper limit can be achieved. Effects such as being able to obtain stopping accuracy and synchronization accuracy are achieved.

Furthermore, the press brake of the present invention has the ram and bed of the earlier invention reversed so that the ram ascends to bend the workpiece. This structure allows the vertical gap between the ram to press upward ( Since the backlash between the pin branch of the beam ram and the slide 1!1 adjustment screw is eliminated by gravity, the balance spring of the prior invention is no longer necessary, and the structure can be simplified accordingly.

[Brief explanation of drawings]

Figure 1 is a front view of the press brake of the present invention, with the left half showing the ram at its lowering limit and the right half showing the ram at its upper limit with a partial cutout; Fig. 1 (A) is the left side of Fig. Figure, Figure 1 (B
) is a cross-sectional view taken along the line B-B in Figure 1, Figures 2 and 3 are enlarged cross-sectional views of the ■-■ line and ■-■ line portion in Figure 1, and Figure 4 is a ram cross-sectional view. FIG. 5 is a cross-sectional view showing the part where the electric motor of the lifting stroke adjusting device is attached, and FIG. 5 is an explanatory view of the operation of the press brake. 1... Press shooting body, 2... Frames on both sides of the main body, 3
...Press cradle at the top of the main body, 4, 5...Vertical guide section on the front side of the frame, 6...Ram, 6a, 6b...
Slide gib, 7.8... Vertical elongated hole, 10... Ram lifting/lowering stroke adjustment device, 11... Slide block, 12... Upward protruding screw, 13... Worm, 1
4... Worm gear, 15... Worm reducer, 1
1... Electric motor, 18... Ram lifting beam, 25-...
・Rotating link, 26.28a, 28b--pin,
29...Circular long hole, 30...Upper mold, 31...Lower mold.

Claims (4)

[Claims] (1) A press machine body in which an upper press holder for attaching an upper mold is installed between a pair of left and right side frames, and a horizontal length that is horizontally suspended between the both side frames of the press machine body; A ram for raising and lowering the lower mold, which is slidably guided so as to be able to move up and down on the front vertical guide section located below the upper press pedestal, and a rear rotation limit whose one end is pin-supported at the upper position of the press pedestal on both sides of the frame. A pair of left and right rotation links that are rotated back and forth within a certain range from the forward rotation limit position to the forward rotation limit position by the operation of a hydraulic cylinder; The ram is held at the lower limit position when the rotary link is at the backward rotation limit position, and the ram is moved to the upper limit position when the rotation link is rotated to the forward rotation limit position. A press brake characterized by being equipped with a pair of left and right ram elevating beams. (2) The ram elevating beam is disposed on the opposing inner surfaces of the frame on both sides of the main body so as to partially protrude from the vertical guide section on the front surface of the frame, and the upper end of the beam and the other end of the rotation link are arranged on the upper part of the main body frame. It is noted that there is an arcuate elongated hole for defining the link rotation range through which the coupling pin is inserted, and that the piston rod end of the hydraulic cylinder is connected to the pin end that protrudes outward from this arcuate elongated hole. A press brake according to claim 1. (3) The ram has a pair of left and right slide blocks on which the lower end of the beam is supported by a pin and is movable in the vertical direction, a worm that screws into the protruding screw of this slide block, and a worm gear that meshes with the worm. 2. The press brake according to claim 1, further comprising a ram lifting stroke adjustment device comprising a worm reducer and an electric motor that reversibly rotates a worm gear of the worm reducer. (4) The slide block is slidably inserted into the vertical elongated hole penetrating the left and right ends of the ram, and when the ram is at its upper limit, the pin branches at the upper and lower ends of the beam and the frame pin branches of the rotating link are aligned with the center of the ram. 4. The press brake according to claim 3, wherein the press brake is configured to be located on a vertical line passing through the press brake.