JPH03234319A - Reciprocating device - Google Patents

Abstract

PURPOSE:To enable positioning at three spots at least and to miniaturize a positioning mechanism by providing a positioning means to orient a piston at a normal position in the middle of a stroke in such a state that fluid pressure is not exerted between a cylinder and a piston. CONSTITUTION:When fluid is sent into a room (a) in the cylinder 20 to exert fluid pressure, the cylinder 20 is pushed up, a stopper 25 comes in contact with the working face 27 of the piston 22 to regulate the elevation of the cylinder 20 and to be oriented at a positioning point of the elevation end. On the contrary, when fluid is sent into a room (b) in the cylinder 20, the cylinder 20 is pushed down, the working face 26 of the piston 22 and an upper wall 23 come in common with each other to regulate the fall of the cylinder 20 and to be oriented at the positioning point of the lowering end. Then, when fluid pressure is not exerted in each room (a), (b) of the cylinder 20, a supporting plate 30 comes in contact with the stopper 25 through the spring pressure of both springs 28, 29, the cylinder 20 comes to a standstill and is oriented at the positioning point in the middle of the stroke.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a reciprocating motion in which a piston is reciprocated relative to a cylinder by feeding fluid such as air or oil into a cylinder and applying fluid pressure. Regarding equipment.

<Prior Art> Conventionally, this type of reciprocating device has been used as a drive source for various movable mechanisms, and has also been used as a positioning mechanism for positioning an object at a predetermined position. For example, in a press brake, in order to define the bending position of a workpiece plate, a back gauge 3 is placed behind the lower die 1, as shown in FIG. The positioning mechanism using the reciprocating device described above is used for positioning at the Miike points of the vertical positions B and C.

This back gauge positioning method is used because when bending the workpiece plate 4 between the lower die 1 and the upper die 2, the bending shape of the pressurizing point is not completely square but circular. This is due to the fact that

In other words, when further bending is performed on the inner side of this arc-shaped bent portion 5, it is necessary to position the back gauge 3 at a predetermined position avoiding the upper or lower arc surface in order to ensure an accurate bending width. There is.

Normally, in this type of reciprocating device, the two positioning points are the rising end or the falling end of the piston within the cylinder.
In order to position the back gauge 3 at three points as described above, it is necessary to connect two such reciprocating devices in series.

<Problems to be Solved by the Invention> However, when two reciprocating devices are connected, the positioning mechanism becomes larger and the cost increases.

This invention was made in view of the above problem, and an object of the present invention is to provide a novel reciprocating device that enables positioning at three points using a single device.

<Means for Solving the Problems> The present invention provides a reciprocating device in which one of a cylinder and a piston is fixed, and the other is reciprocated by a predetermined stroke by fluid pressure applied within the cylinder.
A positioning means is provided between the cylinder and the piston to position the piston at a predetermined position in the middle of the stroke without applying the fluid pressure.

<Function> For example, in the case of a positioning mechanism in which the piston side is fixed and the cylinder side is movable back and forth, when fluid pressure is applied within the cylinder, the cylinder moves relative to the piston and moves to the rising end or falling end. reach 2 between this rising end and falling end
Positioning is possible at points.

Furthermore, when no fluid pressure is applied, the positioning means positions the piston at a predetermined position in the middle of the stroke, so positioning is possible at this point as well, and a third positioning point is obtained.

<Example> FIG. 1 shows a back gauge positioning mechanism 10 in a press brake.

This positioning mechanism 10 is provided at a position behind the lower mold 1, and the back gauge 3 is placed in the normal position shown in the same figure and in the normal position shown in FIG.
) It is for positioning at three points including the upper and lower positions shown in (2). Upper mold 2 is waiting above lower mold 1,
By lowering this upper die 2 and pressurizing the workpiece plate 4 between it and the lower die 1, the workpiece plate 4 is bent into a V-shape.

The back gauge 3 is a slightly thick flat plate material, and its tip end surface serves as a contact surface 11 for abutting the workpiece plate material 4. This back gauge 3 is supported in a horizontal state by a support member 12, and this support member 12 is connected to a reciprocating device 13 according to an embodiment of the present invention.

The illustrated reciprocating device 13 has a rod 21 protruding from the top and bottom of a cylinder 20, the upper and lower ends of the rod 21 are supported by a support frame 14, and the support frame 14 is connected to the press brake machine frame via a fixing member 25. It is fixed at

FIG. 2 shows the internal structure of the cylinder 20,
A piston 22 integral with the rod 21 is disposed inside the cylinder 20 so as to be movable relative to the cylinder 20. Chambers a and b are formed between the piston 22 and the upper wall 23 and lower wall 24 of the cylinder 20, respectively.
Each of the chambers a and b is provided with an outflow port (not shown) for allowing fluid to flow in and out.

A stopper 25 is provided on the inner circumferential surface of the cylinder 20 facing inward at the center of its length, and the piston 22 has a large diameter portion 22a along the inner diameter of the cylinder 20 and the stopper 25.
A series of small diameter portions 22b smaller than the inner diameter of the inner diameter of the inner diameter of the inner diameter of the inner diameter of the inner diameter portion 22b are formed. The upper and lower end surfaces of the large diameter portion 22a form contact surfaces 26° and 27, and when one contact surface 26 contacts the upper wall 23, the cylinder 20 is located at the lower end, and the other contact surface 27 contacts the stopper. 25, the cylinder 20 is at its rising end. The period between the rising end and the falling end corresponds to a stroke in which the cylinder 20 can reciprocate, and the rising end and the falling end serve as the positioning points of the back gauge 3.

Two spring springs 28, 29 and a support plate 30 are disposed between the piston 22 and the cylinder 20, and the cylinder 20 is positioned at a predetermined position in the middle of the stroke without applying fluid pressure. A positioning means is provided for this purpose.

The support plate 30 is located below the stopper 25, one spring spring 28 is between the lower wall 24 of the cylinder 20 and the support plate 30, and the other spring spring 29 is between the upper wall 23 of the cylinder 20 and the piston 22. They are placed between the two.

The outer diameter of the support plate 30 is set larger than the inner diameter of the stopper 25, and holes 31 are formed in the plate surface to allow passage of fluid.

One spring spring 28 elastically biases the cylinder 20 downward, and the other spring spring 29 elastically biases the cylinder 20 upward, and the spring pressure of the spring spring 28 is set to be greater than the spring pressure of the spring spring 29. By doing so, the piston 22 is positioned at an intermediate position of the stroke shown in FIG.

FIG. 3 shows a reciprocating device 13 in which the rod 21 projects only above the cylinder 20. As shown in FIG. In this embodiment, the cylinder 20 side is fixed, the piston 22 side is movable back and forth, and the back gauge 3 is connected to the rod 21. Note that the internal structure of the cylinder 20 in the same figure is the same as that in FIG. 2, and the explanation thereof will be omitted here by assigning corresponding symbols to corresponding structures.

FIG. 4 shows another reciprocating device 13 having a rod 21 projecting upward and downward.

In the illustrated example, an upper wall 23 is provided on the inner peripheral surface of the cylinder 20.
A first stopper 25a is provided near the bottom wall 24, a second stopper 25b is provided near the lower wall 24, and a third stopper 25c having a length matching the length of the piston 22 is provided at an intermediate position between the two. It is provided. At each position above and below this third stopper 25c, support plates 30a and 30b are provided, the outer diameter of which is set larger than the inner diameter of these stoppers 25a to 25c, and which have holes 31 in their plate surfaces. Spring springs 28 and 29 having the same spring pressure are provided between the plate 30b and the lower wall 24 and between the support plate 30a and the upper wall 23, respectively, to constitute positioning means.

In this embodiment, when the support plate 30a hits the stopper 25a, the cylinder 20 is located at the lower end, and the support plate 30a
When b hits the stopper 25b, the cylinder 20 is located at the rising end, and corresponds to a stroke in which the cylinder 20 reciprocates between the rising end and the falling end. Further, when the support plates 30a and 30b hit the upper and lower surfaces of the stopper 25c, the cylinder 20 is positioned at the middle position of the stroke, and the rising end, the falling end, and the middle position of the stroke shown in FIG. These are the three positioning points of 3.

Next, the operation of the above embodiment will be explained.

First, in the embodiment shown in FIG. 2, when fluid is fed into the chamber a in the cylinder 20 and fluid pressure is applied, this fluid pressure overcomes the spring pressure of the spring spring 28 and the cylinder 20 is pushed up. When the contact surface 27 of the piston 22 and the stopper 25 come into contact, the cylinder 20 is restricted from rising, and the cylinder 20 is positioned at the positioning point at the rising end.

Conversely, when fluid is fed into the chamber in the cylinder 20 to apply fluid pressure, this fluid pressure overcomes the spring pressure of the spring spring 29 and the cylinder 20 is pushed down. When the abutting surface 26 of the piston 22 and the upper wall 23 abut, the descending of the cylinder 20 is restricted and the cylinder 20 is positioned at the positioning point of the descending end.

Next, when the fluid pressure is not applied to the chambers a and b of the cylinder 20, the spring pressure of both springs 28 and 29 acts, causing the support plate 30 to come into contact with the stopper 25, and the piston to this support plate 30. The cylinder 20 stably stands still in a state where the cylinders 22 are in contact with each other, and the cylinder 20 is positioned at the intermediate positioning point shown in FIG.

Thus, when performing the first bending process on the workpiece plate 4, the back gauge 3 can be positioned at an intermediate position as shown in FIG. 1 by setting the cylinder 20 in a state where no fluid pressure is applied.

Next, when performing the second bending process on the workpiece plate 4, if the workpiece plate 4 is bent upward as shown in FIG. is sent to apply fluid pressure to position the back gauge 3 at the rising end of the cylinder 20.

Furthermore, if the workpiece plate 4 is bent downward as shown in FIG. do.

The above operation is the same for the embodiment shown in FIG. 3, which differs from the embodiment shown in FIG. 2 only in that the piston 22 side moves.

Next, in the embodiment shown in FIG. 4, when fluid is fed into the chamber a in the cylinder 20 and fluid pressure is applied, this fluid pressure overcomes the spring pressure of the spring spring 28 and the cylinder 20 is pushed up. When the support plate 30b on the lower surface of the piston 22 comes into contact with the stopper 25b, the upward movement of the cylinder 20 is restricted, and the cylinder 20 is positioned at the positioning point at the rising end.

Conversely, when fluid is fed into the chamber in the cylinder 20 to apply fluid pressure, this fluid pressure overcomes the spring pressure of the spring spring 29 and the cylinder 20 is pushed down. When the support plate 30a on the upper surface of the piston 22 contacts the stopper 25a, the downward movement of the cylinder 20 is restricted, and the cylinder 20 is positioned at the positioning point at the downward end.

Next, when the chambers a and b of the cylinder 20 are set to a state in which no fluid pressure is applied, the spring pressures of both spring springs 2B and 29 act on the support plate 30a.

30b is in contact with the upper and lower surfaces of the stopper 25c, and the piston 22 is in contact with each of the support plates 30a and 30b, and the cylinder 20 is stably stationary, and the cylinder 20 is at the intermediate positioning point shown in FIG. Localize.

In the above embodiment, the reciprocating device 13 of the present invention is used as a positioning mechanism for a bag gauge in a press brake, but the present invention is not limited to this, and it can of course be used for positioning other mechanisms.

<Effects of the Invention> As described above, this invention provides a
Since a positioning means is provided to position the piston at a predetermined position in the middle of the stroke without applying fluid pressure,
This invention enables positioning at at least three points with a single reciprocating device, making the positioning mechanism more compact and cost-effective compared to the conventional positioning mechanism in which two reciprocating devices are connected. Achieves a remarkable effect of achieving the purpose.

[Brief explanation of drawings]

FIG. 1 is a front view showing a schematic configuration of a positioning mechanism in a press brake, FIG. 2 is a sectional view of a reciprocating device according to an embodiment of the present invention, and FIGS. 3 and 4 are other embodiments of the present invention. FIG. 5 is a sectional view showing an example, FIG. 5 is a front view showing a positioning state by the positioning mechanism, and FIG. 6 is an explanatory view showing a positioning point of a back gauge in a press brake. 10... Positioning mechanism 20... Cylinder 22... Piston 25, 25a, 25b, 25c... Stopper 28, 29... Spring spring 30, 30a, 30b... Support Plate 13... Reciprocating device 21... Rod

Claims (1)

[Claims] In a reciprocating device in which one of a cylinder and a piston is fixed and the other is reciprocated by a predetermined stroke by fluid pressure applied within the cylinder, there is a gap between the cylinder and the piston. A reciprocating device comprising positioning means for positioning the piston at a predetermined position in the middle of the stroke without applying the fluid pressure.