GB2126136A

GB2126136A - Automatic tool changer device

Info

Publication number: GB2126136A
Application number: GB08323001A
Authority: GB
Inventors: Norito Miyajima
Original assignee: Okuma Machinery Works Ltd
Current assignee: Okuma Corp
Priority date: 1982-08-30
Filing date: 1983-08-26
Publication date: 1984-03-21
Also published as: GB2126136B; GB8323001D0; DE3330705A1; JPS5934935U

Abstract

An automatic tool changer for a machining centre comprises a carrier (8) mounted on a guide beam (4) for movement between the magazine (13) and the tool changing position, an arm driving device (19) carried by the carrier so as to rotate 90 DEG about an axis parallel to the direction of movement of the carrier and to move up and down relative to carrier (18), and a tool changing arm (20) provided at its ends with tool grippers (20a, 20b) and rotatably mounted on the arm driving device. The arm (20) is also translationally movable relative to driving device (19) along the arm axis (20c). Therefore, the tool changing arm (20) can perform a tool change between the tool storage magazine (13) and any one of the vertical spindle (7), horizontal spindle (9) and the attachment spindle (10). <IMAGE>

Description

SPECIFICATION Automatic tool changer device This invention relates to machining centres and to tool changing systems used therein. It provides in a machining centre having a spindle head carrying a vertical spindle and a horizontal spindle perpendicular to the vertical spindle, a tool changer provided with a single tool changing arm capable of performing a tool changer between both spindles and a tool storage magazine. More particularly, the invention is concerned with a tool changer for use in such a machining centre which is also capable of making a tool change of the tool in an attachment spindle attached to the vertical spindle.

Large-size vertical-type machining centres having a horizontal spindle which can be indexed through rotation in a horizointal plane with respect to a vertical spindle are known. Some of these known machining centres incorporate a tool changer having a single tool changing arm swingable by 900 between a first position where the axis of rotation of the arm takes a vertical posture and a second position where the same takes a horizontal posture, so that the arm can perform a tool change between a tool storage magazine and the vertical spindle, as well as between the tool storage magazine and the horizontal spindle. This type of machining centre is disclosed in Japanese Patent Publication No.

38109/1 976 published on October 20, 1976.

Due to the diversification of use of the machining centres and a demand for the effective use of the machine, it is a current measure to mount an attachment spindle to permit even large-size machines to perform complicated machining on various positions of the work. In general, however, the attachment spindle is a specific one adapted to carry a special-purpose tool and, hence, it is mounted or demounted together with the tool in accordance with the machining steps to be performed. On the other hand, however, when an ordinary tool is used on the attachment spindle, it is necessary to work manually on the machining centre to mount and demount such an ordinary tool on and from the attachment spindle. This requires a considerable preparation time and this impairs the efficiency of the machining operation undersirably.

According to the present invention, there is provided a machining centre having a spindle head carried by a guide beam for movement along the guide beam between a machining position and a tool changing position, a vertical spindle and a horizontal spindle carried by the spindle head, and means for attaching an attachment spindle to the vertical spindle, the attachment spindle having an auxiliary horizontal spindle, the centre including an automatic tool changer comprising: a tool storage magazine spaced from the spindle head and storing a plurality of tools; a carrier mounted on the guide beam for movement along the guide beam between the position of the magazine and the tool changing position; an arm driving device carried by the carrier in such a manner as to be able reciprocatorily to rotate 900 about an axis parallel to the direction of movement of the carrier and to move up and down by a distance equal to the distance between the horizontal spindle and the auxiliary horizontal spindle; and a tool changing arm provided at both its longitudinal ends with tool grippers and secured to the arm a driving device for rotation as a unit therewith so as to take either a horizontal position or a vertical position; wherein the tool changing arm is secured to the arm driving device in such a manner that, when the tool changing arm is in the horizontal position and in the vertical position, the tool changing arm can rotate within a horizontal plane and within a vertical plane and move translationally in the vertical direction and in the horizontal direction, respectively, with respect to the arm driving device; whereby the tool changing arm can perform a tool change between the tool storage magazine and any one of the vertical spindle, the horizontal spindle and the attachment spindle.

Further features of the invention will become apparent from the following description of a preferred embodiment, which is illustrated by way of example in the accompanying drawings in which: Figure 1 is a front elevational view of a machining centre equipped with an automatic tool changer in accordance with a preferred embodiment of the invention; and Figures 2A to 2F are schematic perspective views of essential parts of the tool changer and an attachment spindle attached to a machining centre, illustrating the tool changing operation performed by the tool changer.

Referring first to Figure 1, this shows a machining centre in front elevation. The machining centre has a bed 1 which slidably carries a table 2 for numerical control of position.

Upright columns 3 and 3 stand each side of the bed 1 and a beam 4 is fixed to the upper ends of the columns 3, 3 so that the columns 3, 3 and the beam 4 in combination constitute a gate-like structure. The beam is provided at its front side with a horizontal guide surface along which a spindle head 5 is slidable horizontally to the right and left by a numerical position control. The spindle head 5 carries a spindle sleeve 6 for vertical sliding motion under numerical position control, in which is a spindle 7. To the end of sleeve 6 is secured a vertical spindle and a rotary head 8 adapted to be indexed through rotation in a horizontal plane to four positions at 900 intervals. The rotary head 8 rotatably carries a horizontal spindle 9 to which torque is transmitted from the vertical spindle 7.An attachment spindle 10 is detachably attached to the spindle 7 and rotatably carries an auxiliary horizontal spindle 11 which is adapted to be rotated by the torque transmitted from the vertical spindle. An attachment housing device 12 is mounted at one side of one of the columns 3, 3.

The attachment housing device 12 accommodates a plurality of attachment spindles 10 with their attaching surfaces directed upwardly to permit an indexing operation so that these attachment spindles can be successively indexed to an attachment attaching position.

When the desired attachment spindle 10 is indexed to the attachment attaching position, the spindle 7 of the spindle head 5, which has been moved along the beam 4 to the attaching position, is lowered to permit an automatic attaching of the attachment spindle. At the same side of the column 3 as the attachment housing device 12, is a tool storage magazine 13 constructed as a unit with or separately from the column 3. The magazine 13 includes a plurality of tool pots 14 connected in a series by means of an endless chain. The tool pots hold respective tools T and are adapted to be indexed to a tool changing position in accordance with numerical control instructions. The indexed tool pot 14 is then clamped by a clamping device 21.A sub-arm device 1 5 mounted on an end of the beam 4 near the side surface of the magazine frame is adapted to take out the indexed tool T from the magazine and to return the old tool T' into the vacant tool pot. The sub-arm device 15 has an arm 16 which is adapted to be rotated, together with a hydraulic cylinder device 1 5a, 900 by a hydraulic motor (not shown) between a vertical position in which a gripper 1 6a on the end of the arm 16 is directed downwardly, as shown by solid line in Figure 2B, and a horizontal position in which the gripper 1 6a takes a position adjacent to the magazine as shown by chain-line in Figure 2B. The arm 16 is also movable in the longitudinal direction thereof by a hydraulic cylinder device (not shown) between an advanced position and a retracted position.Further the arm 1 6 is adapted to be located at either one of two positions on an axis parallel to the axis of the pot 14, by the operation of the hydraulic cylinder device 1 5a. It is herein to be noted that, when the arm 16 is moved between the above-mentioned two positions, this arm 16 is moved unitarily with a cylinder 1 5a' of the hydraulic cylinder device 1 5a along a fixed piston disposed within the cylinder 1 5art. In other words, all parts of the device 15 appearing in Figure 2B are moved unitarily when the arm 16 is moved between the two positions in question.A ready station 1 7 disposed at one side of the subarm device 15 and mounted on an end of the beam 4 is pivotally supported by a shaft 1 7a for a rotation between a horizontal position where it faces the gripper 1 6a.of the arm 16 as shown in solid lines in Figure 2B and a vertical position where the same is directed downwardly as shown in chain-lines in Figure 2B, by the operation of a hydraulic cylinder which is also omitted from the drawings. The guide surface of the beam 4 slidably supports also a carrier 18 movable to the left and right under numerical control, in a side-byside relation to the spindle head 5. The carrier 18 is provided at its lower end with an arm driving device 19.The arm driving device 19 is adapted to drive a tool changing arm 20 through 900 rotation in either rotational direction and for 1 800 rotation, and also between two positions in the direction of the axis of rotation. More specifically, the arm 20 is fitted substantially at its lengthwise mid portion to the outer end of a rotary shaft 20C (see Figure 2D) which is rotatably carried by the arm driving device 19. As will be seen from Figure 2F, the arm 20 is swingable through 900 together with the rotary shaft 20C between the vertical position shown in solid lines in Figure 2F and the horizontal position shown in chain-lines in Figure 2F, so as to take either at the vertical position or the horizontal position.In addition, the arm 20 is further rotatable 1 800 in the clockwise direction from the horizontal position mentioned above so as to take the position 1 800 away from the horizointal position. Furthermore, the rotary shaft 20C is slidable with respect to the arm driving device 19 in the axial direction of the shaft 20C so that the arm 20 can take either an advanced position where it is advanced by a predetermined distance from the arm driving device 19 and a retracted position near the arm driving device 1 9.

The arm driving device 19 is rotatable together with a shaft 19a around an axis of the latter. The shaft 19a is mounted in a bracket 18a of the carrier 18. The device 19 is rotatable 900 between the position 18. The device 19 is rotatable 900 between the position shown in Figure 2C where the rotary shaft 20C of the tool changing arm 20 is held vertically and a position shown in Figure 2D in which the shaft 20C is held horizontally. This rotation of the arm driving device 19 is caused by rotating the shaft 19a by means of a hydraulic cylinder device (not shown) disposed in the bracket 1 8a of the carrier.Further, the abovementioned bracket 18a is mounted on the carrier 18 movably in the upward and downward directions with respect to the carrier 18, and this movement of the bracket 1 8a is caused by a hydraulic cylinder device (not shown) disposed in the carrier 18. Thus, the arm driving device 19 is movable, together with the bracket 18a, up and down with respect to the carrier 18 by a distance which is equal to the distance between the horizontal spindle 9 and the auxiliary horizontal spindle 11.

The tool changing arm 20 itself is a known one provided at its both ends with grippers 20a, 20b as shown, for example, in Japanese Utility Model Publication No. 3634/1983. The grippers 20a and 20b are enabled to be simultaneously operated by a driving device (not shown) in the rotary shaft 20C so as to make clamping and unclamping actions concurrently with each other (This concurrent changing made by grippers 20a, 20b is hereinafter referred to as "first clamp"), but are operable independently of each other to perform clamping action mechanically and unclamping action upon a mechanical contact at the tool clamping position (This indepednent clamping is hereinafter referred as a "second clamp"). It is to be noted that the tool changing arm 20 and grippers 20a, 20b are illustrated in the Figures only schematically, and the mechanism for operating the grippers 20a, 20b is not illustrated since the mechanism is well-known as shown in Japanese Utility Model Publication No. 3634/1983 mentioned above.

The operation of the tool changer of the invention is as follows. It is assumed here that an attachment shaft 10 is already,attached to the spindle head 5. The clamping device 21 is operated in accordance with the instructions given by the numerical controller so that the tool storage magazine 13 is unclamped for an indexing rotation as indicated by arrow g in Figure 2A thereby to index the desired tool T to permit the latter to be clamped by the clamping device 21. Then, the arm 16 taking the horizontal position on the sub-arm device 15 is advanced as indicated by arrow a in Fig. 2b to allow the gripper 16a to grip the tool T, followed by the movement in the direction of axis of the rotary shaft as indicated by arrow b by the operation of the cylinder device 1 5a, thereby to extract the tool T from the tool pot 14.Subsequently, the arm 16 is retracted as indicated by arrow c and rotated 900 by a hydraulic motor (not shown) to make the gripper 16a point downwardly. The arm 16 is then advanced downwardly as indicated by arrow d to bring the tool into axial alignment with the ready station 17, followed by an axial movement as indicated by arrow e so that the tool T is inserted into the ready station 17.

After the tool T is clamped by the ready station 17, the arm 18 is lifted and then moved to the retracted position as indicated by an arrow f.

Subsequently, the ready station 17 is rotated 900 to the position shown in chain-line in Figure 2B so that the tool is directed downwardly. Thereafter, the arm driving device 19 on the carrier 18 in the stand-by position is lowered and the carrier 18 is moved to the left so that the tool T on the ready station 17 is gripped (by the first clamp action) by the gripper 20b on the tool changing arm 20 which is in the horizointal position, and the ready station 17 unclamps the tool. Subsequently, the arm 20 is moved downwardly in the axial direction of the rotary shaft 20C thereby to extract the tool T from the ready station 17. The ready station 17 then rotated 900 clockwisely to resume the horizontal position.

Subsequently, the carrier 18 is moved rightward and the arm 20 is moved upward in the axial direction of the rotary shaft 20C, while the arm driving device 19 is raised together with the bracket 18a to take the stand-by position. Then, as an instruction is given for a tool change on the auxiliary horizontal spindle, the main shaft sleeve 6 is raised to permit the orientation of the rotary head 8 of the horizontal spindle, as well as the orientation of the attachment spindle 10.

Thereafter, the spindle head 5 is moved to the left and located at the tool changing position. On the other hand, the carrier 18 is moved to the right to position which is slightly back from the tool changing position, followed by a downward movement of the arm driving device 19. The arm driving device is then rotated 900 in the counterclockwise direction from the position shown Figure 2C to move the arm from the horizontal position to the vertical position shown in Fig. 2D.

The carrier 18 is moved to the right in this state to the tool changing position, while the first clamp of both grippers 20a and 20b is dismissed.

Thereafter, the arm 20 is rotated 900 clockwise from the state shown in Figure 2D to the position shown in chain-lines in Figure 2F so that the gripper 20a grips the old tool T' on the auxiliary horizontal shaft 11 of the attachment spindle. At this time, the mechanical second clamp is unclamped upon contact with the tool and a first clamp is made upon completion of the gripping. Subsequently, the arm 20 is moved in the axial direction of the rotary shaft 20C to extract the old tool T' from the auxiliary horizontal shaft 11, and then the arm 20 is rotated 1800 in the clockwise direction and in turn moved in the axial direction of the shaft 200 to insert the new tool T into the auxiliary horizontal shaft 11. Then the new tool T is clamped in the shaft 11 and the first clamp is released.Thereafter, the arm 20 is rotated 900 in the counter-clockwise direction to take the vertical position, and effects the first clamp again.

Then, the carrier 18 is moved slightly leftwardly and the arm driving device 19 effects 900 clockwise rotation to make the arm 20 take the horizontal position. Thereafter, the arm driving device 19 is raised and is then moved to the left to take the standby position.

In order to store the old tool T', the arm driving device 1 9 of the carrier 1 8 is lowered and the arm 20 is moved downwardly in the direction of the axis of the rotary shaft 20C. On the other hand, the ready station 17 is rotated 900 counterclockwisely so as to be directed downwardly. A subsequent leftward movement of the carrier 18 makes the tool axially aligned with the ready station 17, and the arm 20 is retracted in the axial direction of the rotary shaft 20C to insert the old tool T' into the ready station 17 to make the latter clamp the old tool T' while unclamping the first clamp. The carrier 18 is then moved to the right to the stand-by position.Subsequently, as the ready station 17 is rotated 900 in the counter-clockwise direction to take the horizontal position, the arm 16 is advanced downwardly to make the gripper 16a grip the old tool T' and the latter is unclamped in the ready station.

A subsequent movement of the sub-arm device in the direction of axis of the rotary shaft causes a retracting motion of the arm 16 while extracting the old tool T'. The sub-arm device 15 is then rotated 900 clockwisely to make the arm 16 take a horizontal position adjacent to the tool storage magazine. Thereafter, the arm 16 is advanced towards the magazine to bring the old tool T' into axial alignment with the tool pot 14 and the subarm device 15 is reversed in the axial direction to insert the old tool T' into the tool pot 14.

Then, the arm 16 is retracted to the stand-by position to permit the tool storage magazine 13 to be rotated for the next indexing operation.

When the spindle 7 does not carry any attachment spindle, the upward and downward movement of the arm driving device at the tool changing position is required neither by the tool change for the vertical spindle nor by the tool change for the horizontal spindle 9. Namely, when it is desired to conduct a tool change between the tool storage magazine and the vertical spindle, the tool changing arm is positioned horizontally, whereas, for performing a tool change between the tool storage magazine and the horizontal spindle 9, the arm driving device takes a position rotated 900 to make the arm take the vertical position. Thus, when no attachment spindle is used, the tool change can be made in the same manner between the spindles and the tool storage magazine, although the upward and downward movement of the arm driving device is omitted as being unneccessary.

As has been described, according to the invention, there is provided a tool changer having a single tool changing arm capable of performing a tool change between vertical and horizontal spindles and a tool storage magazine of a machining centre, wherein the tool changing arm is further adapted to perform a tool change between an attachment spindle optionally attached to the vertical spindle. With the tool changer of the invention, therefore, it is possible to eliminate any human labor for tool changing even when the machining centre employs an attachment spindle for performing a machining having a number of complicated steps, so that unmanned control of the machining centre can be achieved. In addition, the tool changer of the invention contributes to a shortening of the time required for the tool change and to an enhancement of safety through elimination of accident which may otherwise, be caused in the manual tool changing work.

The use of the tool changer of the invention is preferred also from economical and managerial points of view, because it advantageously eliminates the necessity for the preparation of ordinary tools specifically for the attachment.

Moreover, the time required for the tool change on the attachment spindle is further shortened because the tool change is made without requiring the change of the attachment. For the same reason, the machining centre equipped with the tool changer of the invention requires fewer kinds of attachment advantageously.

Claims

1. A machining centre having a spindle head carried by a guide beam for movement along the guide beam between a machining position and a tool changing position, a vertical spindle and a horizontal spindle carried by the spindle head, and means for attaching an attachment spindle to the vertical spindle, the attachment spindle having an auxiliary horizontal spindle, the centre including an automatic tool changer comprising:: a tool storage magazine spaced from the spindle head and storing a plurality of tools; a carrier mounted on the guide beam for movement along the guide beam between the position of the magainze and the tool changing position; an arm driving device carried by the carrier in such a manner as to be able reciprocatorily to rotate 900 about an axis parallel to the direction of movement of the carrier and to move up and down by a distance equal to the distance between the horizontal spindle and the auxiliary horizontal spindle; and a tool changing arm provided at both its longitudinal ends with tool grippers and secured to an arm driving device for rotation as a unit therewith so as to take either a horizontal position or a vertical position; wherein the tool changing arm is secured to the arm driving device in such a manner that, when the tool exchanging arm is in the horizontal position and in the vertical position, the tool changing arm can rotate within a horizontal plane and within a vertical plane and move translationally in the vertical direction and in the horizontal direction, respectively, with respect to the arm driving device; whereby the tool changing arm can perform a tool change between the tool storage magazine and any one of the vertical spindle; the horizontal spindle and attachment spindle.

2. A machining centre having a tool changing mechanism substantially as hereinbefore described with reference to the accompanying drawings.