JPS6354505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic tool changer for a machining center that takes out a required tool from a magazine containing a large number of tools and automatically replaces it with a tool on a spindle.

Conventionally, this type of device rotates an arm with a tool gripping portion at its tip against a magazine containing a large number of tools, grips the required tool with the gripping portion, and then moves the arm. The tool is automatically attached to the spindle by rotating it again, transferring it to just below the spindle, and raising it as it is. Also, at the same time, with an arm provided on the opposite side of the arm,
The tool attached to the spindle is gripped and transferred and stored in a magazine, which allows for automatic tool exchange.

However, in order to drive the rotation of this arm,
Generally, a direct-acting air cylinder is used because it operates quickly and is easy to handle. Although this air cylinder has such good points, due to its nature, it is impossible to stop the air cylinder quickly and accurately, especially at an intermediate position between the starting end and the ending end.

Especially in machining centers, in order to automatically exchange tools between the magazine and the spindle,
It is absolutely necessary to quickly and accurately stop the tool at the gripping position of the arm, the insertion position, and the normal waiting position of the arm.
If this is not sufficient, the arm and magazine or main shaft will collide with each other, and even if there is no collision, automatic exchange will be impossible. For this reason, conventionally, two direct-acting air cylinders are used to avoid such a situation as much as possible.

The present invention was developed under these circumstances, and avoids the use of two expensive direct-acting air cylinders, and avoids the above-mentioned drawbacks by using one rotary air cylinder. This system is designed to simplify the mechanism and operation of the armshaft so that it can operate accurately without any trouble.One rotary air cylinder is used to rotate the armshaft, and a guide case is attached to the armshaft. This guide case is provided with an upper lateral groove, a lower lateral groove, and a vertical groove that connects these up and down, and a cushion ring that has a cushioning force in the circumferential direction is fitted to this guide case to tighten the guide case. The upper and lower lateral grooves are aligned with the ring groove provided on the cushion ring, and both grooves are made to overlap, and a piece protruding from the arm shaft is slidably fitted into each of these grooves, and this piece is inserted into the overlapping groove. When the tool collides with the section, the inertial energy of the arm and the tool held is absorbed by the cushioning force, and then the tool is positioned by gently hitting the end of the horizontal groove of the guide case.

This will be explained with reference to the diagram.

Reference numeral 1 denotes a rotating air cylinder, which can rotate a rotating shaft 2 left and right.

3 is a direct-acting air cylinder installed in parallel with the rotary air cylinder 1, which can move the arm shaft 4 up and down.

A spline structure 5 is formed between the rotation shaft 2 and the arm shaft 4, and the rotation of the rotation shaft 2 is transmitted to the arm shaft 4, and the shaft 4 is moved up and down by the direct-acting air cylinder 3.

Arms 6, 6' are horizontally attached to the lower end of the arm shaft 4, and grips 7, 7' for gripping the tool 8 are formed at the tips of each of the arms 6, 6'.

The arms 6, 6' selectively grip tools 8 in a magazine (not shown) by their rotation;
This can be transferred to the main shaft of the machine, or vice versa, or both operations can be performed at the same time.

9 is located below the arm shaft 4,
This guide case 9 is fixed to the machine frame 10 with bolts 20, 20'. An upper cushion ring 11 is fitted above the guide case 9, and a lower cushion ring 12 is fitted below it. Reference numerals 21 and 21' designate cushioning devices fixed to the machine frame 10 on the outside of each cushioning ring 11 and 12, and this applies a cushioning force to each cushioning ring 11 and 12, the details of which will be explained later.

Reference numeral 13 denotes a piece fixed to the arm shaft 4. This piece 13 operates integrally with the arm shaft 4 as it rotates and moves up and down. (described next) and grooves (described next) cut in the upper and lower cushion rings 11, 12 that overlap with these (described next).

As shown in FIG. 2a, the guide case 9 includes:
Upper lateral grooves 14, 14, lower lateral grooves 14', front side vertical grooves 15, and back side vertical grooves 15' are cut on the front and back sides.

The pieces 13 slide in these grooves 14, 14', 15, 15' as described above, but the upper horizontal grooves 14, 1
4 and the lower lateral groove 14' are shown in Fig. 2b,
As shown in c, the ring grooves 16, 16 of the upper cushion ring 11 fitted into the guide case 9,
Similarly, the ring groove 17 of the lower cushion ring 12
They overlap exactly.

In addition, as shown in FIGS. 3 and 4, the upper lateral groove 14 and the ring groove 16, and the lower lateral groove 14' and the ring groove 17 do not have the sides of the grooves exactly coincident with each other, but have the same width in the lateral direction. An overlap is formed at

This overlap l has important significance. For example, in FIG. 3, when the piece 13 rotates clockwise between the upper lateral groove 14 and the ring groove 16, the piece 13 collides with the overlap l until the overlap l disappears. The cushioning effect of the impact force is obtained, which will be explained in more detail below.

21', 21, as explained earlier, are cushion devices, which include spring pins 18, 1.
8' are provided opposite to each other, and these spring pins 18, 1
8', each roller 1 is attached integrally to the outer periphery of the upper and lower cushion rings 11, 12 and facing each other.
9 and 19' are in contact with each other.

That is, in FIG. 3, when the piece 13 collides with the overlap l as described above, the piece 13 first presses the upper cushion ring 11 clockwise, and at the same time, the roller 19 pushes the spring pin 18 into the cushion. Push the other roller 1 into the device 21.
9' is pushed by the spring pin 18', and eventually the overlap l disappears, and the grooves 16 and 14 of the side of the piece 13, the upper cushion ring 11, and the guide case 9 are pressed.
The sides of match with exactly one line. (This state shows the left side of the piece 13 shown in the figure, the guide case 9, and the upper cushion ring 11.
This is the same as the state in which the groove sides of . ) When this overlap l disappears and this side becomes exactly one line, the upper cushion ring 1
An overlap l is formed on the opposite side of the guide case 9 from the guide case 9, that is, at the portion indicated by the arrow m in the figure.

The effect will be explained.

As explained above, the arms 6 and 6' selectively grip the tool 8 in the magazine and transfer it to the main shaft of the machine, or vice versa, or perform both operations at the same time. The basic operation is shown in Figures 5A to 5F.

Figure A shows the basic position of the arms 6, 6'. In Figure B, arms 6 and 6' rotate (as an example, 76
degree), the tool 8 is being gripped by one of the gripping portions 7. Next, as shown in FIG. 3C, the arms 6 and 6' descend downward, separate from the magazine and spindle, and rotate in the direction of the arrow shown in FIG. (180 degrees as an example) Next, it rises as shown in the figure (E), and the tool 8 is automatically inserted into the main shaft of the machine. After this is over,
As shown in the figure, the arms 6, 6' are rotated 76 degrees in the opposite direction and assume the basic position again. However, in this case, the positions of the grips 7, 7' are upside down from their initial positions, but this does not have any special meaning.

The above operation is performed by the arm shaft 4 to which the arms 6, 6' are attached, being rotated by the rotary air cylinder 1 and driven up and down by the direct-acting air cylinder 3. A piece 13 fixed to the shaft 4 is connected to the guide case 9 and each groove 14 of each cushion ring 11, 12.
By sliding within 14', 15, 15', 16, and 17, accurate positioning is achieved without giving any impact during operation, which will be described in detail.

In FIG. 2c, piece 13 occupies basic position A'. (This basic position A' is a position corresponding to Fig. 5 A, and is indicated by the same symbol A with a dash. The other positions are also the same. In Fig. 6 A, piece 13 is the basic position. This shows the relationship between the bridge 13 and the cushion rings 11, 12 of the guide case 9 when it is in position A'.The same applies hereafter.) Next, from the basic position A', the upper horizontal groove 14 and the ring groove 16 are shown. It rotates 76 degrees along
(See Figure B and Figure 6B). Then, it descends from point A' to point C' (see Figure 5 C and Figure 6 C),
It rotates 180 degrees from point C' and reaches point N' (see Figure 5 D and Figure 6 D), then continues to rise and reaches point E' (see Figure 5 E and Figure 6 E). After completing the tool transfer, it reaches the point ' and assumes the basic position (5th
(See Figures F and 6).

By the way, when piece 13 reaches point B' from point A',
In other words, in the situations shown in Figure 5B and Figure 6B,
This is when the gripping section 7 of the arm 6 has just automatically gripped the tool 8 of the magazine. Therefore, if the gripping part 7 goes too far toward the tool 8 or collides with it too strongly, the device will be damaged, and if it cannot reach the tool 8, it will not be able to grip the tool 8 sufficiently. , it becomes impossible to transfer the tool 8, and its operation becomes inaccurate. Therefore, at this point RO', it is absolutely necessary to stop the gripping part 7 at an accurate position and not to apply a strong impact to the tool 8 at this time.

In addition, in the situations shown in Fig. 5 D and Fig. 6 D, automatic tool transfer is impossible unless the tool 8 gripped by the grip part 7 of the arm 6 is positioned exactly below the main axis of the machine. . Furthermore, if the bridge 13 and the guide case 9 strongly collide when stopping, the device itself will be damaged, and it will also be impossible to completely stop the device at an accurate position.

The states shown in FIGS. 5 and 6 are when the arm has once again assumed its normal position, but if it is not positioned correctly at this point, it will come into contact with parts such as the head and break the arm.

However, in the present invention, each lateral groove 14, 1
4' and the ring grooves 16 and 17, the piece 13 first collides with the cushion rings 11 and 12, and the cushion ring 1
1, 12 are engaged with cushion devices 21, 21', so that the arms 6, 6' are stopped gradually and in a damped manner.

Therefore, the arms 6, 6' and the tool 8 do not collide with each other, and the arms 6, 6' can always be stopped at desired and accurate positions without damaging the device itself. .

Of course, this operation is carried out reliably at the three points mentioned above, and when the arms 6 and 6' operate in the opposite direction, each cushion ring 1
1, 12 and the overlap l formed on the opposite side of the guide case 9 provides a similar damping effect at three points.

According to the present invention, even if an air cylinder is used which makes it impossible to make accurate intermediate stops, there will be no collision between the arm and the tool, and the arm will always be stopped at an accurate position, avoiding damage to the device itself. Therefore, there is no need to use a plurality of air cylinders as in the conventional case.

Furthermore, since the device itself is relatively simple, its manufacturing cost is low, and tools can be transferred and replaced automatically and accurately, increasing the work efficiency of the machine.

[Brief explanation of drawings]

Figure 1 is a vertical sectional side view of the entire device, Figure 2a is a perspective view of the guide case, Figure 2b is a perspective view of the cushion ring, and Figure 3c is a perspective view of the two fitted together. FIG. 1 is a cross-sectional view taken along the line A-A in FIG. 1, FIG. 4 is a cross-sectional view taken along the line B-B, FIG. FIG. 5 is a cross-sectional view showing the relationship between the bridge, the guide case, and the cushion ring when they are in the positions shown in FIGS. 1, 2... Rotating air cylinder, 3... Direct acting air cylinder, 4... Arm shaft, 6, 6'...
Arm, 7...Gripping part, 9...Guide case, 1
0...Machine frame, 11,12...Cushion ring,
14... Upper lateral groove, 14'... Lower lateral groove, 15...
...Front side vertical groove, 15'...Back side vertical groove, 16,17...
...Ring groove, 21...Cushion device, 18,1
8'...Bullet pin, 19,19'...Roller.

Claims (1)

[Scope of Claims] 1. An arm having a tool grip formed at its tip is attached to the lower end of an arm shaft that is rotated by a rotary air cylinder and moved up and down by another direct-acting air cylinder, and the arm shaft has: A guide case fixed to the machine frame is fitted, an upper horizontal groove and a lower horizontal groove are cut into the guide case, and both grooves are connected by a vertical groove, and a cushioning force is applied to the top and bottom of this guide case in the circumferential direction. Fit the cushion rings provided on both cushion rings, align the ring grooves provided on both cushion rings with the upper and lower lateral grooves of the guide case, and make sure that the sides of each lateral groove and each ring groove are exactly aligned. An automatic tool changer for a machining center in which a piece protruding from an arm shaft is slidably fitted into each horizontal groove, ring groove, and vertical groove, with an overlap formed in the lateral length. 2. An automatic tool changer for a machining center according to claim 1, wherein upper lateral grooves are provided on the front and back of the guide case, and each of the upper lateral grooves and the lower lateral grooves are connected by a front side vertical groove and a back side vertical groove. 3. An automatic machining center according to claim 1, wherein two rollers are provided oppositely protruding from the outer periphery of the cushion ring, and each roller is engaged with a spring pin provided oppositely to the cushion device. Tool changer. 4. The automatic tool changer for a machining center according to claim 2, wherein ring grooves are cut on the front and back sides of the upper cushion ring.