JP3150386B2 - Automatic tool changer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tool changer for a machine tool such as a machining center, and more particularly to an automatic tool changer for accommodating a plurality of tools in a hollow hole of a main shaft composed of a hollow shaft.

[0002]

2. Description of the Related Art The applicant of the present invention accommodates a plurality of tools movably in the axial direction in a hollow hole of a main shaft composed of a hollow shaft, and replaces these tools with a chuck provided at a front end opening of the main shaft. Japanese Patent Application No. 63-93867 and Japanese Patent Application No. 63-228092.
(Refer to Japanese Patent Application Laid-Open No. 1-264734).

In the automatic tool changer according to the above-mentioned patent application, a plurality of tools contained in a guide cylinder (tool holder) inserted into a hollow hole of a main shaft are reciprocated in the axial direction to move the tools to the chuck. For replacement, a tool changing cylinder device is provided for each tool.

[0004]

However, in such a structure, a plurality of cylinder devices and switches and other auxiliary devices for confirming the operation of the cylinder devices are individually required according to the number of tools. In addition, not only the number of parts is large and the cost is high, but also the whole device is large and heavy. In addition, wiring and assembly are troublesome and costly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a plurality of tools can be alternately replaced with the chuck by reciprocating one push rod in the axial direction. It is an object of the present invention to provide an automatic tool changer which can be used.

[0006]

In order to achieve the above object, in the automatic tool changer of the present invention, the tool replacement unit has an index cam groove on an inner peripheral surface of a rear end portion, and A guide cylinder inserted into the hollow hole of the main shaft,
The guide cylinder is disposed annularly along the inner peripheral surface thereof,
A plurality of operating rods individually accommodated in the tool, the first and second engaging grooves being provided on the inner surface of each operating rod and being axially separated; One clutch shaft fitted into the center portion of the guide cylinder so as to be surrounded by the plurality of operating rods, and movably and rotatably disposed in the axial direction; and a rear end of the clutch shaft. A clutch body that is fixed to the portion and that is indexed and rotated by engaging with the index cam groove when reciprocating in the axial direction; and a clutch body separated from the clutch body toward the axial front end side and fixed to the clutch shaft. An indexing plate which engages with the first engagement groove of the operating rod indexed by rotation of the clutch body; Slidably in the direction A locking plate that engages with the second engagement groove of an operating rod other than the operating rod indexed by the rotation of the latch body to prevent the operating rod from moving in the axial direction; And the interposition between the locking plate and the locking plate, while urging the locking plate to be fixed at a predetermined position in the guide cylinder,
A return spring that urges the clutch shaft to return to the standby position via the index plate; and is fitted to the guide cylinder so as to be movable only in the axial direction from a rear end thereof, and is engaged with the clutch body at a front end. A push rod provided with a cam to be moved, and driving means for reciprocating the push rod in the axial direction.When the push rod advances, the cam first engages with the clutch body, and the clutch body is moved. When the index plate is indexed and rotated along the cam groove while being pressed, the index plate engages with the first engagement groove of the indexed operating rod, and at the same time, the locking plate Engaging the second engagement groove of the operating rod other than the rod, and subsequently moving the clutch shaft forward with the indexed operating rod while compressing the return spring with the indexing plate;
While the tool connected to the operating rod is inserted into the chuck and moved to the clamp position, when the push rod is retracted, the clutch shaft is moved through the index plate by the action of the return spring. Together with the tool, the tool is accommodated in the standby position, and the clutch body rotates by a predetermined angle along the cam groove during the movement.

As a means for reciprocating the push rod in the axial direction, a cylinder device is usually used.

[0008]

With the above construction, each time the push rod repeatedly moves forward and backward in the guide cylinder in the axial direction, the plurality of operating rods accommodated in the guide cylinder are sequentially reciprocated in the axial direction. A tool exchange is performed by inserting a tool connected to the selected one operating rod into the chuck and clamping it, and at the time of retreating, returning the tool from the chuck to a standby position.

If the stroke of the push rod is reduced, the index plate is sequentially engaged with the first engaging groove of the adjacent operating rod without performing tool change. Regardless of the arrangement, any tool can be selected and exchanged.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a longitudinal front view of the first half of the automatic tool changer according to the present invention, and FIG. 2 shows a longitudinal front view of the latter half.

Reference numeral 1 denotes a spindle head, and 2 denotes a spindle, which comprises a hollow shaft (quill) having a hollow hole 3 extending over its entire length, and a chuck 4 is attached to a front end opening. The spindle 2 has a ball spline nut 5 and a ball screw nut 6.
Are fitted. An outer cylinder 7 fitted to the front end portion of the main shaft 2 is connected to the ball spline nut 5, and a transmission pulley 8 is fitted to the outer cylinder 7 while a boss 9 fixed to the ball screw nut 6. A transmission pulley 10 is fitted on the transmission pulley 10.

The ball spline nut 5 and the ball screw nut 6 fitted to the spindle 2 as described above are rotatably supported by the spindle head 1 via bearings 11 and 12, respectively. The ball spline nut 5 is supported by the support frame 13
And a first servomotor 14 attached to the spindle head 1 via a timing belt 15 and a transmission pulley 8. The ball screw nut 6 is attached to the spindle head 1 via a support frame 16. It is rotationally driven by the two servo motors 17 via the timing belt 18 and the transmission pulley 10. When the ball spline nut 5 is driven to rotate, the main shaft 2 rotates. When the ball screw nut 6 is driven to rotate, the main shaft 2 reciprocates in the axial direction. Therefore, when the nuts 5 and 6 are simultaneously driven to rotate, the spindle 2 reciprocates in the axial direction while rotating. Therefore, drilling, tapping, and the like are performed using a drill or other rotating tool T clamped on the chuck 4. Can be. At this time, the main shaft 2 and the outer cylinder 7 rotate synchronously.

The chuck 4 comprises a main body 21 having a collet 20 and a tapered sleeve 2 fitted on the main body 21.
2, a front cover 23 fitted on the sleeve 22, and a disc spring 2 interposed between the sleeve 22 and the front cover 23.
4 and six unclamping pins 25 (only two of them are shown in FIG. 1) disposed at equal intervals in the circumferential direction on the outer peripheral portion of the main body 21. The main body 21 is the main shaft 2
And the front cover 23 is fixed to the main body 21. The tapered sleeve 22 is fitted on the collet 20 so as to be slidable in the axial direction, and is urged by a disc spring 24 to clamp the collet 20. The unclamping pin 25 extends through the main body 21 in parallel with the axis of the main shaft 2, the inner end flange 25a abuts the flange 22a of the sleeve 22, and the outer end 25b extends rearward from the main body 21. It is protruding.

When the main shaft 2 moves backward to the rearmost position, the outer end 25b of the unclamping pin 25 comes into contact with the end surface of the outer cylinder 7 and is pushed into the sleeve 22 side, so that the inner end flange is formed. The collet 20 is unclamped by pushing the sleeve 22 against the disc spring 24 at the portion 25a.

Reference numeral 30 denotes a tool replacement unit for replacing a plurality of tools T with the chuck 4. The unit 3
0 is a guide cylinder 31 inserted into the hollow hole 3 of the main shaft 2;
A plurality of (four in the illustrated example) operating rods 32 disposed annularly along the inner peripheral surface of the guide cylinder 31 and accommodated in the guide cylinder 31 so as to be movable in the axial direction; A clutch shaft 33 which is inserted into the center portion of the guide cylinder 31 so as to be surrounded by and is disposed so as to be movable and rotatable in the axial direction. And a push rod 34 (see FIG. 2) that is movably inserted and engages with the clutch shaft 33. These members 31 to 34 are all formed of plastic or resin in order to reduce the weight.

The guide cylinder 31 has a tapered portion 35 converging toward the chuck 4 at a front end portion thereof and a thin continuous tapered portion connected to the tapered portion 35, as shown in FIG. A cylindrical portion 36 is provided. Behind the taper portion 35, the operating rods 32 are annularly arranged along the inner peripheral surface of the guide body 31 and accommodated therein. Tool holding part 37 provided with through holes 38 for holding the
Are formed. The tool T is individually placed on the inner wall surface extending from the front end opening of the through hole 38 to the taper portion 35.
A guide groove (not shown) leading to 6 is provided corresponding to each through hole 38. The tip of the cylindrical portion 3b is supported by the main body 21 of the chuck 4 via a bearing. On the other hand, a guide groove 39 having a cross-shaped cross section for guiding the clutch shaft 33 and the push rod 34 movably only in the axial direction is provided inside the rear end of the guide cylindrical body 31 and is connected to the rear end of the guide groove 39 and will be described later. Indexing cam groove 40 for indexing and rotating clutch body 50
And a guide groove 41 having a cross-shaped cross section, which is continuous with the cam groove 40 and guides the push rod 34 movably only in the axial direction. The cross groove of the guide groove 41 has the same phase as the cross groove of the guide groove 39, but is slightly shallower. A mounting flange 42 protrudes from the rear outside of the guide cylinder 31.

The operating rod 32 is formed on an elongated cylindrical shaft inserted into the through hole 38, and a first engaging groove 43 for engaging an index plate described later is provided on the inner surface of the rear end, while the inner surface of the front end is provided. Is provided with a second engagement groove 44 which engages with a locking plate described later. The two engaging grooves 43 and 44 open toward the center of the guide cylinder 31, and the groove bottom is formed in an arc shape. A tool T is connected to the front end of the operating rod 32 via a wire 45 and a connection fitting 46. A bearing (not shown) is interposed between the tool T and the connection fitting 46, and the tool T is rotatable with respect to the connection fitting 46.

The clutch shaft 5 has a clutch body 5
The index plate 51 and the locking plate 52 are attached to each other at an interval in the axial direction.

The clutch body 50 is fixedly mounted on the rear end of the clutch shaft 33. As shown in FIGS. 5 and 11, four clutch claws 53 projecting radially out of phase by 90 degrees are provided on the outer peripheral portion. These clutch claws 53 are engaged with the guide grooves 39 to connect the clutch shaft 33 to the guide cylinder 3.
It is movably guided only in the axial direction with respect to 1. At both ends of each clutch claw 53, inclined cam surfaces 53a and 53b for causing indexing rotation operation described later are provided (FIG. 1).
4 and FIG. 16).

The indexing plate 51 is fixedly mounted on the clutch shaft 33 at a predetermined distance from the clutch body 50 at the front end in the axial direction. Each notch 54
Two short perimeters 55, 55 and one long perimeter 56 are left between them (see FIGS. 6 and 12).

The clutch shaft 33 is shown in FIG.
At the rear standby position shown in FIG. 6A, as shown in FIG.
The second first engagement groove 43 is engaged. On the other hand, the clutch body 5
0, the peripheral edge portion 56 engages only with the engaging groove 43 of the operating rod 32 connecting the selected tool T, and the engaging groove 43 of the other operating rod 32 splits. The delivery plate 51 does not engage (see FIG. 12). Therefore, only the operating rod 32 of the selected tool T can move in the axial direction in conjunction with the clutch shaft 33.

The locking plate 52 is axially slidably fitted to the clutch shaft 33 at a position further away from the indexing plate 51 to the front end side in the axial direction, and as shown in FIGS. Has a ridge 58 that engages with a key groove 57 extending in the axial direction provided in the boss, and rotation is prevented by the ridge 58. The locking plate 52 has a shape in which one arc-shaped notch 59 is provided on the outer peripheral portion of the disk. And
When the clutch shaft 33 is at the standby position shown in FIG. 3A, the peripheral edge portion 60 of the locking plate 52 engages with the second engagement groove 44 of each operating rod 32 as shown in FIG. Prevent axial movement. On the other hand, when the clutch body 50 is indexed and rotated, as shown in FIG. 13, only the operating rod 32 connecting the selected tool T is opposed to the arc-shaped notch 59 and Although it is separated and the movement in the axial direction is free, the peripheral edge portion 60 of the locking plate 52 is engaged with the engagement groove 44 of the other operating rod 32, and the movement in the axial direction is prevented.

A return spring 61 is interposed between the index plate 51 and the locking plate 52. By the return spring 61,
The locking plate 52 is located at the rear end 37a of the tool holder 37 (see FIG. 1).
And the clutch shaft 33 is urged via the index plate 51 so as to return to the standby position shown in FIG. Also, the clutch shaft 33
The first half portion provided with the key groove 57 passes through the locking plate 52 rotatably supported by the rear end 37a of the tool holding portion 37, and is inserted into a through hole 62 provided at the center of the tool holding portion 37, It is possible to move forward.

As shown in FIG. 14, the push rod 34 is inserted axially movably from the rear end of the guide cylinder 31 and is inserted into the large-diameter shaft portion 63 connected to the front end. A cam 64 for engaging with the inclined cam surface 53a of the clutch piece 53 is provided, and four guide projections 65 projecting radially out of phase by 90 degrees on the outer peripheral portion thereof.
The push rod 34 is guided movably only in the axial direction with respect to the guide cylinder 31 by engaging the ridges 65 with the guide grooves 41 and 39. On the other hand, the rear part of the push rod 34 protrudes and extends from the guide cylinder 31, and the rear end thereof is connected to the cylinder device 67 via the connection plate 66 as shown in FIG. Although not shown in the drawings, the air cylinder device 67 is supported and fixed to a support frame 70 described later.

The index cam groove 40 has a partition wall 39 at the rear end of the guide groove 39 as shown in a developed view of FIG.
The groove is formed in an annular groove extending in the circumferential direction across "a", and the diameter of the groove bottom is the same as the diameter of the guide groove 39 so that the clutch claw 53 can be engaged and rotated. The groove wall surface adjacent to the guide groove 41 is provided with four inclined cam surfaces 68 extending from the partition wall 41 a across the guide groove 41, and the inclined cam surface 53 a of the clutch pawl 53 is in close contact with the inclined cam surface 68. Engage and index rotation.

A step 68a is formed between the inclined cam surfaces 68 adjacent to each other. On the other hand, four inclined cam surfaces 69 extending across the partition wall 39a are provided on a groove wall surface adjacent to the guide groove 39, and the inclined cam surfaces 53b of the clutch claws 53 are closely engaged with the inclined cam surfaces 69. It is indexed and rotated. The inclined cam surface 69 does not have a step corresponding to the step 68a of the inclined cam surface 68.
FIG. 15A shows the upper end surface of the development view, and FIG.
(C) shows the lower end face of the developed view.

In FIGS. 1 and 2, reference numeral 70 denotes a support frame of the tool changing unit 30. The support frame 70 is mounted movably in parallel with the axis of the spindle 2 along a guide rail 71 provided on the bottom of the spindle head 1, and is connected to the rear end of the spindle 2 via a bearing 72. . A guide cylinder 31 inserted into the hollow hole 3 of the main shaft 2 from the rear end opening.
Is fixed to the support frame 70 with the set screw 73, while the cylindrical portion 36 at the front end of the guide cylinder 31 fitted in the hollow hole 3 is relatively rotatably supported on the chuck body 21 via the bearing 74, so that the tool is The replacement unit 30 is detachably fitted in the hollow hole 3 of the main shaft 2.

The operation of the automatic tool changer having the above configuration will be described in accordance with the operation sequence shown in FIGS.

When performing tool change, first, the spindle 2 is retracted to the rearmost position, and the sleeve 22 is pressed against the disc spring 24 by the unclamping pin 25 abutting against the end surface of the outer cylinder 7, and the collet 20 is moved. Unclamp.

FIG. 16A shows a state where the push rod 34 is stopped at the rear end position shown in FIG. 3A. At this stop position, the clutch body 50 of the clutch shaft 33 and the cam 64 at the tip of the push rod 34 are separated. On the other hand, each clutch claw 53 of the clutch body 50 engages with the inclined cam surface 68 of the index cam groove 40 and the step portion 68a,
The rotation is blocked. The peripheral edges 55 and 56 of the indexing plate 51 engage with the first engagement grooves 43 of each operating rod 32, and the peripheral edge 60 of the locking plate 52 engages with the second engaging groove 43 of each operating rod 32. Each operating rod 3 is engaged with the groove 44.
2 is prevented from moving in the axial direction, and the operating rod 32 is prevented from moving unexpectedly, thereby preventing a mistake in indexing the tool T (see FIGS. 6 and 7).

In this state, when the cylinder device 67 is operated and the push rod 34 is advanced, the cam 64 engages with the inclined cam surface 53a of the clutch pawl 53 as shown in FIG. After the clutch pawl 53 is disengaged from the inclined cam surface 68 by moving it in the axial direction against the spring 61, the other inclined cam surface 53 b is indexed into the cam groove 4.
The inclined cam surface 69 is abutted. Subsequently, FIG.
As shown in FIG. 16C, the clutch pawl 53 is guided by the inclined cam surface 69 and moves obliquely, and as shown in FIG.
4 and is engaged with the guide groove 39. Due to the movement of the clutch pawl 53, the clutch shaft 33 is indexed and rotated by 45 degrees.

When the clutch shaft 33 is indexed and rotated as described above, the indexing plate 51 interlocked with the indexing shaft 51 has the peripheral edge 56 of the operating rod 32 connecting the specific tool T indexed. Only the engaging groove 43 is engaged, and the remaining operating rod 3 is engaged.
The second engagement groove 43 is not engaged (see FIG. 12). On the other hand, the locking plate 52, which also rotates in conjunction with the clutch shaft 33, is unlocked when only the operating rod 32 connecting the indexed tool T is opposed to the arc-shaped notch 59, The movement in the axial direction becomes free (see FIG. 13). When the push rod 34 moves forward in this state, the clutch pawl 53 of the clutch body 50 moves along the guide groove 39 as shown in FIG. 16 (e), and the clutch shaft 33 moves forward in the axial direction with the rotation prevented. Moving. In conjunction with this, the operating rod 32 locked to the index plate 51 is pushed out toward the chuck 4, and the tool T connected to the operating rod 32 is inserted into the collet 20 of the chuck 4, and It stops at the clamp position protruding a predetermined length from the front end. At this time, the return spring 61 is compressed by the index plate 51 (see FIGS. 1 and 3B). Then, spindle 2
Is slightly advanced by the ball screw nut 6, the unclamping pin 25 separates from the outer cylinder 7, the collet 20 is automatically clamped by the disc spring 24, and the tool T is gripped.

In this state, the main spindle 2 rotates, and cutting by the tool T is performed. During machining, the operating rod 32 connecting the push rod 34 and the tool T is stopped at the forward position, that is, at the tool pushing position in FIG. 3B.

When machining is completed and the next tool change is to be performed, the spindle 2 is retracted to the final rear end position and the collet 20 is unclamped in the same manner as described above.
7 is operated to move the push rod 34 backward. When the push rod 34 starts retreating, the clutch shaft 3
3 is also retracted by the return spring 61, and the tool T connected to the operating rod 32 interlocked with this is pulled out from the collet 20 and returned to the standby position. Then, when the clutch body 50 moves backward to the index cam groove 40 again, as shown in FIG.
When the clutch pawl 53 locked to the step 4 and the stepped portion 64a again comes into contact with and engages with the inclined cam surface 68 of the index cam groove 40, and the push rod 33 further retreats, FIG.
As shown in FIG. 16G, the clutch pawl 53 is disengaged from the cam 64 and the stepped portion 64a, and is moved obliquely by being guided by the inclined cam surface 68. As shown in FIG. At the position locked to 68a, rotation is prevented by the inclined cam surface 68 and the stepped portion 68a, and FIG.
Return to the state. By the movement of the clutch pawl 53, the clutch shaft 33 is further indexed and rotated by 45 degrees,
Return to the standby position in FIG. Hereinafter, tool change is performed by repeating the same operation as described above.

When it is desired to select a tool T different from the tool T disposed next to the tool T and replace it, the push rod 34 is moved to a position where the clutch body 50 is indexed and rotated by 45 degrees, that is, the clutch body 50 is moved. After advancing to a position where it is indexed and rotated along the cam groove 40, the long peripheral portion 56 of the indexing plate 51 is sequentially arranged adjacently by repeating forward and backward retraction of a short stroke of retreating to the rear end position again. By engaging the operating rod 32 with the first engagement groove 43, the desired tool T can be selected and exchanged.

[0037]

As described above, according to the present invention,
By simply reciprocating one push rod 34 in the axial direction, an index plate 51 provided on the clutch shaft 33 that moves in the axial direction in conjunction with the push rod 34 is connected to the selected tool T. First engagement groove 43 of operating rod 32
, The plurality of tools T housed in the hollow hole of the main shaft 2 can be arbitrarily exchanged. Therefore, only one tool changing cylinder device 67 for operating the push rod 34 may be used, so that not only the manufacturing cost is reduced but also the size and weight of the device can be reduced.

In the present invention, the operating rod 32 other than the indexed operating rod 32 is locked and held by the locking plate 52 engaged with the second engagement groove 44, and is prevented from moving in the axial direction. As a result, the indexing of the tool is assured.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a first half of an automatic tool changer according to the present invention.

FIG. 2 is a vertical sectional front view of the latter half part.

FIG. 3 is a longitudinal sectional front view showing a standby state (A) and an operating state (B) of the tool changing unit.

FIG. 4 is an enlarged cross-sectional view taken along line 4-4 in FIG.

FIG. 5 is an enlarged cross-sectional view taken along line 5-5 in FIG.

FIG. 6 is an enlarged sectional view taken along line 6-6 in FIG.

FIG. 7 is an enlarged sectional view taken along line 7-7 in FIG.

8 is an enlarged sectional view taken along line 8-8 in FIG. 3 (A).

FIG. 9 is an enlarged sectional view taken along line 9-9 in FIG. 3 (A).

FIG. 10 is an enlarged sectional view taken along line 10-10 of FIG. 3 (B).

FIG. 11 is an enlarged cross-sectional view taken along line 11-11 of FIG. 3 (B).

FIG. 12 is an enlarged sectional view taken along line 12-12 of FIG. 3 (B).

FIG. 13 is an enlarged sectional view taken along line 13-13 of FIG. 3 (B).

FIG. 14 is a perspective view schematically showing a main part of an indexing mechanism.

FIG. 15 is a development explanatory view of an index cam groove.

FIG. 16 is an explanatory diagram showing an operation sequence of a clutch body.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spindle head 2 spindle 3 hollow hole 4 chuck 30 tool replacement unit 31 guide cylinder 32 operating rod 33 clutch shaft 34 push rod 39, 41 guide groove 40 indexing cam groove 43 first engagement groove 44 second engagement Groove 50 Clutch body 51 Indexing plate 52 Locking plate 53 Clutch pawl 64 Cam

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23Q 3/157

Claims (4)

(57) [Claims] 1. A machine tool according to claim 1, wherein a plurality of tools are axially movably accommodated in hollow holes of a main shaft formed of a hollow shaft, and these tools are replaced with chucks provided at a front end opening of said main shaft. In the automatic tool changer, the tool replacement unit has an index cam groove on an inner peripheral surface of a rear end portion, and a guide cylinder fitted in a hollow hole of the main shaft; It is arranged annularly along the inner peripheral surface,
And a plurality of operating rods which are accommodated movably in the axial direction and individually connect the tools, and first and second axially spaced apart inner surfaces of the operating rods.
An engagement groove, and one clutch shaft that is inserted into the center portion of the guide cylinder so as to be surrounded by the plurality of operating rods, and that is disposed so as to be movable and rotatable in the axial direction. A clutch body fixed to the rear end of the clutch shaft and engaged with the index cam groove when reciprocating in the axial direction and indexed to rotate; An index plate fixedly mounted on the clutch shaft and engaged with the first engagement groove of the operating rod indexed by rotation of the clutch body; A shaft is slidably fitted in the shaft relative to the shaft, and engages with the second engagement grooves of the operating rods other than the operating rod indexed by the rotation of the clutch body. A locking plate for preventing movement in the direction; The clutch shaft is interposed between the indexing plate and the locking plate, and urges the locking plate to be fixed at a predetermined position in the guide cylinder, while the clutch shaft is interposed through the indexing plate. A return spring for urging the return to the standby position; a push rod fitted in the guide cylinder so as to be movable only in the axial direction from a rear end thereof, and a front end provided with a cam engaging with the clutch body; Drive means for reciprocally moving the rod in the axial direction. When the push rod advances, the cam first engages with the clutch body, and index rotation along the cam groove while pushing the clutch body. Then, the indexing plate is engaged with the first engaging groove of the indexed operating rod, and at the same time, the locking plate is indexed by the second operating rod other than the operating rod.
The clutch shaft moves forward integrally with the indexed operating rod while the return spring is compressed by the indexing plate, and is connected to the operating rod. While the tool is inserted into the chuck and moved to the clamp position, when the push rod is retracted, the clutch shaft is returned to the standby position together with the operating rod through the index plate by the action of the return spring, An automatic tool changer configured to accommodate the tool at a standby position and to rotate the clutch body at a fixed angle along the cam groove during the movement thereof. 2. The automatic tool changer according to claim 1, wherein the guide cylinder has a tapered portion converging toward the chuck at a front end portion and a cylindrical portion continuous with the tapered portion. 3. A cylindrical portion of the guide cylinder inserted into a hollow hole of the main shaft is rotatably supported by the chuck, and a rear end portion is movable in an axial direction in conjunction with the main shaft. 3. The automatic tool changer according to claim 2, being fixed to a support frame. 4. The indexing plate is sequentially engaged with a first engaging groove of an adjacent operating rod without performing a tool changing operation by repeating advance and retreat of the small stroke by the push rod. 4. An automatic tool changer according to claim 1, wherein the automatic tool changer comprises: