JPH0351063Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a device for preventing workpiece lifting in a machine tool, and is suitable for application to a hobbing machine having a quill type support arm.

<Prior Art> FIG. 4 shows a schematic cross-sectional view of a part of a hobbing machine having a conventional quill-type support arm. In FIG. The quill 13 is attached to be vertically movable by a cylinder drive device 14, and a work arbor 15 is attached to the tip (lower end) of the quill 13. On the other hand, a lower fitting 16 is arranged below the lower fitting 1.
By placing the work 17 on the quill 13 and lowering the quill 13, the work arbor 15 is inserted into the work 17 and the work 17 is pressed against the work arbor 15 to clamp the work 17. In such a hobbing machine, if the work arbor 15 is raised when unclamping the work 17, the work 17 may be lifted up while remaining in close contact with the work arbor 15. This lifting of the workpiece 17 not only poses a risk of falling, but also impedes automatic operation.

Therefore, a device has been devised to prevent the work 17 from being lifted up as the work arbor 15 rises. FIG. 5 is a cross-sectional view of a conventional workpiece lifting prevention device, and FIG. 6 is a cross-sectional view taken along the line taken from FIG. 5. This conventional workpiece lifting prevention device uses spring force to prevent the workpiece from being lifted up.
This is to prevent the number 7 from being carried away. That is, as shown in FIGS. 5 and 6, the quill 13
A pair of ironing bars 18 are supported on the support arm 12 so as to be movable in parallel to the moving direction of the ironing bars 18, and a work stopper 19 member that can come into contact with the outer edge of the workpiece 17 is attached to the lower end of the ironing bars 18, while supporting the ironing bars 18. A compression coil spring 20 provided on the lower surface of the arm 12 biases it downward. The lower end position of the squeezing bar 18 is restricted by a regulating plate 21 attached to the upper part of the bar that comes into contact with the support arm 12, and at the lower end position, the workpiece stopper 19 is pushed against the workpiece 17 through a slight gap. are arranged to face each other. In addition, a collar 2 is attached to the upper end of the squeezing bar 18.
2 is attached, and the regulating plate 21 is attached to the support arm 1.
2, the plate 23 attached to the upper end of the quill 13 moves against the collar 22 by a number 10 near the end of the upward stroke of the quill 13.
It is designed to engage at a millimeter point.

In such a conventional device, first, the loader magazine 24 places the workpiece 17 on the lower fixture 16, and when the quill 13 is lowered, the workpiece arbor 1
5 and the squeezing bar 18 are coming down. The work arbor 15 descends until it hits the upper surface of the work 17 and clamps the work 17, while the ironing bar 1
8, the regulation plate 2 is moved several tens of millimeters from the beginning of the descent of the plate 23 due to the movement of the quill 13.
1 comes into contact with the support arm 12 and stops at its lower end position, and the work stopper 19 stops the work 17.
(the state shown in Fig. 5).

Thereafter, when processing of the workpiece 17 is completed, the quill 13 is raised by an unclamp signal. Then, the work 17 is unclamped as the work arbor 15 rises, but at this time, when the work 17 is lifted up with the work arbor 15, the work 17 hits the work stopper 19 and the work arbor 15 is lifted up.
The workpiece 17 is released from the workpiece arbor 1.
It deviates from 5. Subsequently, as the quill 13 rises further, the plate 23 moves to the collar 22.
The work stopper 19 is retracted upward by pushing up the squeezing bar 18 against the spring force of the spring 20. Thereafter, the loader magazine 24 lifts and rotates, so that the workpiece 17 is unloaded.

<Problems to be solved by the invention> However, since the conventional work lifting prevention device uses the spring 20 to urge the squeezing bar 18 downward, the following problems occur. .

(1) When changing the setup of the work arbor 15 or lifting the loader magazine 24, it is necessary to retract the bar 18 upward to avoid interference. must be ensured. Therefore, the spring 20 becomes very long, and it is difficult to obtain sufficient spring force due to space limitations.

(2) Coupled with the fact that the spring force of the spring 20 is limited as described above, the workpiece 17 is at the position where the spring 20 is most extended, that is, at the position where the spring force is the weakest.
As the work arbor 15 is raised, the work 17 is initially lifted up against the spring force, and then midway through, the spring force overcomes the adhesion force between the work arbor 15 and the work 17, and the work 17 is lifted up. There have been cases where the product has fallen, making it unreliable.

The present invention solves the problems with conventional workpiece lifting prevention devices that utilize springs, and is capable of obtaining sufficient squeezing force without increasing the installation space. is intended to provide.

<Means for solving the problem> The structure of the workpiece lifting prevention device in the machine tool according to the present invention to achieve this purpose is applicable to a machine tool that clamps the workpiece by pressing a fixture against the workpiece. , a first straining bar supported movably in parallel to the moving direction of the fixture; and a first ironing bar that moves together with the fixture and moves when the fixture clamps the workpiece.
a fluid pressure cylinder that urges the ironing bar in the direction of the ironing bar; a work stopper that is provided at the tip of the ironing bar and comes into contact with the workpiece to prevent the workpiece from being lifted up with the fixture;
a stopper for restricting the movement of the ironing bar in the first direction at a position where the workpiece stopper is a predetermined distance away from the workpiece; an engagement piece that engages with a member that moves together with the fixture near the end of its movement stroke when moving in a second direction opposite to the first direction, and moves the squeezing bar in the second direction; It is characterized by having the following.

<Operation> The squeezing bar is urged in the direction of the work by the fluid pressure of the fluid pressure cylinder, and the work stopper is locked by the stopper at a position a predetermined distance away from the work. When the work is lifted up with the fixture in this state, the work hits the work stopper and comes off from the fixture. At this time, the squeezing force of the workpiece stopper against the workpiece is given by the fluid pressure of the fluid pressure cylinder, and by adjusting the pressure, a sufficient squeezing force can be obtained. On the other hand, when unclamping, near the end of the movement stroke of the fixture, the engagement piece engages with a member that moves together with the fixture, and this movement causes the squeezing bar to move against the pressure of the fluid pressure cylinder. The work stopper will be evacuated.

<Example> Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view of a work lifting prevention device according to an embodiment of the present invention, FIG. 2 is a view taken in the direction of the arrow in FIG. 1, and FIG.

As shown in FIGS. 1 to 3, a pair of straining bars 25 are supported on the support arm 12 so as to be movable in parallel to the moving direction of the quill 13 that drives the work arbor 15, which is a fixture, and the straining bars A work stopper 26 that can come into contact with the outer edge of the work 17 is attached to the lower end of the workpiece 25. Also, Quill 13
A plate 27 is attached to the upper end of the plate 27, and a fluid pressure cylinder 28 is fixed to the plate 27. The squeezing bar 25 is inserted into the fluid pressure cylinder 28, and a piston portion 29 is provided at the upper part of the squeezing bar 25, and the piston portion 29 is slidably fitted into the fluid pressure cylinder 28.
The squeezing bar 25 is first
In the figure, the workpiece arbor 15 is biased downward, that is, in the first direction in which it moves when clamping the workpiece 17. On the other hand, a stopper 31 that engages with the workpiece stopper 26 is fixed to the machine body, and the workpiece stopper 26 holds the workpiece on the lower fixture 16.
The stopper 31 comes into contact with the workpiece stopper 26 at a position a predetermined distance apart from the workpiece stopper 7, thereby restricting movement of the ironing bar 25 in the first direction. Further, a collar 32, which is an engaging piece, is attached to the upper end of the squeezing bar 25, and this collar 32 is arranged so that the work arbor 15 is positioned upward in FIG. 1, that is, in a second direction opposite to the first direction.
When the hydraulic cylinder 28 moves in the direction of
When the fluid pressure cylinder 28 further moves in the second direction, the squeezing bar 25 is moved against the fluid pressure.

Therefore, in such a device, when the loader magazine 24 first places the work 17 on the lower fixture 16 and lowers the quill 13, the work arbor 1
5 and fluid pressure, the squeezing bar 25 descends. The work arbor 15 descends until it hits the top surface of the work 17 and clamps the work 17, while the straining bar 25 moves several tens of millimeters from the beginning of the downward movement of the hydraulic cylinder 28 as the quill 13 moves, and the work stopper 26 moves to the stopper 31. It stops when it comes into contact with the work stopper 2.
6 is in a state facing the workpiece 17 (the state shown in FIG. 1).

Thereafter, when processing of the workpiece 17 is completed, the quill 13 is raised by an unclamp signal. Then, the work 17 is unclamped due to the rise of the work arbor 15. At this time, when the work 17 is lifted up with the work arbor 15, the work 17 hits the work stopper 26 and the work arbor 15 is unclamped.
The workpiece 17 is released from the workpiece arbor 1.
It's out of 5. Subsequently, as the quill 13 rises further, the fluid pressure cylinder 28 attached to the plate 27 comes into contact with the collar 32,
The squeezing bar 25 is pushed up against the fluid pressure of the fluid pressure cylinder 28, and the work stopper 26 is retracted upward. Thereafter, the loader magazine 24 lifts and rotates, thereby transporting the work 17. Here, the work stopper 26 is
When the work stopper 2 is in contact with
6 is energized by fluid pressure, by adjusting the pressure a sufficient squeezing force can be obtained, and the workpiece stopper 26 is prevented from rising due to the lifting force of the workpiece 17. be able to. In this embodiment, since the fluid pressure cylinder 28 is provided above the quill 13, the structure of the lower surface of the support arm 12 can be simplified, and workability such as changeover work can be improved.

<Effects of the invention> As described above in detail with reference to one embodiment, according to the invention, the squeezing bar is energized by the fluid pressure from the fluid pressure cylinder, so it can be used without increasing the installation space. A sufficient squeezing force can be obtained, and a stable and reliable work lifting prevention device can be provided.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a workpiece lifting prevention device according to an embodiment of the present invention, Fig. 2 is a view taken in the direction of the arrow in Fig. 1, Fig. 3 is a cross-sectional view taken at - in Fig. 1, and Fig. 4 is a conventional FIG. 5 is a cross-sectional view of a conventional work lifting prevention device, and FIG. 6 is a cross-sectional view taken from FIG. 5. In the drawing, 13 is a quill, 15 is a work arbor,
16 is a lower attachment part, 17 is a work, 25 is a ladder bar, 26 is a work stopper, 28 is a fluid pressure cylinder, 31 is a stopper, and 32 is a collar.

Claims (1)

[Scope of utility model registration request] In a machine tool that clamps a workpiece by pressing a fixture against the workpiece, there is provided an ironing bar that is movably supported in parallel to the moving direction of the fixture, and that moves together with the fixture and that the fixture is a fluid pressure cylinder that urges the squeezing bar in a first direction in which it moves when clamping the workpiece; and a fluid pressure cylinder that is provided at the tip of the squeezing bar and comes into contact with the workpiece so that the workpiece is lifted up with the fixture. a work stopper for restricting movement of the ironing bar in the first direction at a position where the work stopper is a predetermined distance away from the work; a stopper for restricting movement of the ironing bar in the first direction; and engaging a member that moves with the fixture near the end of its travel stroke when the fixture moves in a second direction opposite the first direction to move the straining bar to the second direction. A device for preventing a workpiece from being lifted up, comprising an engaging piece that moves the workpiece in two directions.