TOOL EXCHANGE SYSTEM FOR MACHINE TOOLS

Abstract: The tool changer has a Z slider (3) which is movable on a column (1) and supports a spindle (5). A spindle head (4) incorporates a tool mounting and detachment system. A magazine (9) is supported by a support rotatable about the column and carries tools (8) in grips (10). An elastic element (71) elastically holds the magazine support in a standby position during machining and a cam (11) counters the force of the elastic element and rotates the magazine support to bring the magazine to a tool changing position when the spindle head rises. When the spindle head is in a topmost position, magazine and spindle gears (20,21) come into engagement.

Description: This invention relates to an improvement applicable to a tool exchange or replacement system for a machining tool. More specifically, this invention relates to an improvement applicable to a tool exchange or replacement system for a machining tool for the purpose to prohibit any mutual disturbance from occurring between a work to be machined and any tool which is mounted on a magazine of the machine tool in the neighborhood of the tool presently employed or between the work to be machined and any part of the machine tool, thereby an operator of the machine tool is given adequate clearance for operation of the machine tool. Presently available are a variety of tool exchange or replacement systems each of which has a magazine on which a plurality of tools are mounted to be selectively employed. We were successful in developing such a tool exchange or replacement system for machine tools as was mentioned above, and the subject of GP-A-0088131. Figs. 1 and 2 show one embodiment of the above mentioned tool exchange or replacement system for machine tools, illustrated respectively in one position in which a tool 8 is coupled with a main spindle 5 and is kept apart from a magazine 9 and bevel gears 20 and 21 is are uncoupled from each other to allow machining and in the other position in which the tool 8 is not coupled with the main spindle 5 but is mounted on the magazine and the bevel gears 20 and 21 are coupled to each other to allow a tool to be exchanged or replaced by another. Referring to the drawings, this tool exchange or replacement system and which is available in the prior art, is provided with a bevel gear 20 supported by the end of a main spindle 5 rotatably supported by a spindle head 4, a magazine 9 which is movable along the spindle head 4 in the vertical direction and which holds a plurality of tools 8, and the other bevel gear 21 is supported by the magazine 9 for coupling with the aforementioned bevel gear 20 at the upper end position of the stroke of the spindle head 4. After machining finishes at the position illustrated in Fig. 1, the tool 8 employed for the finished machining is replaced by another tool 8, by unclamping the used tool 8 from the main spindle 5 by employing a tool attachment/removal means (not shown) such as a drawbar etc. and by lifting the spindle head 4 which rotatably houses the main spindle 5 to the position illustrated in Fig. 2, the magazine 9 remaining at the position illustrated in Fig. 1. This upward movement of the spindle head 4 causes the used tool 8 which was already unclamped from the main spindle 5 during the aforementioned step, to be drawn out of the main spindle 5. The upward movement of the spindle head 4, incidentally, causes the bevel gears 20 and 21 to be mutually coupled. Then, the main spindle 5 is rotated to rotate the bevel gears 20 and 21 which rotate the magazine 9, until another tool 8 which will be employed for the next machining meets the main spindle 5 during this rotation step, and the tool 8 which was employed in the last machining moves to another position at which it does not meet the main spindle 5, before lowering the spindle head 4 along the magazine 9 until the aforementioned bevel gears 20 and 21 are uncoupled and the newly selected tool 8 is clamped with the main spindle 5 by employing the tool attachment/removal means (not shown) such as a drawbar etc. to return to the machining position illustrated in Fig. 1. At the machining position illustrated in Fig. 1, one of the tool holders of the magazine 9 stays close to the lower end of the main spindle 5. Other holders of the magazine 9 not connected with the main spindle 5 remain adjacent to the main spindle 5, while the rotation of the main spindle 5 causes the tool 8 alone to rotate. The tools 8 mounted on the tool holders (not shown) located adjacent to the tool holder facing the main spindle 5, cause some disturbance to the operator's work space. The aforementioned tool exchange or replacement system needs no drive which is employed exclusively for exchanging or replacing tools, because a drive for driving a main spindle is employed also for rotating the magazine for indexing a tool. As a result, the structure thereof is simple and the tool exchange or replacement system is convenient particularly from the practical viewpoint. The aforementioned tool exchange or replacement system which is illustrated in Fig. 1, allows one of the tool holders of the magazine to remain surrounding the lower end of the main spindle, resultantly disturbing the operator in his work in the neighborhood of the machining area. Further, some of the tool holders of the magazine located adjacent to the above mentioned one also disturbs the operator in his work in the neighborhood of the machining area. The object of this invention is to remove the aforementioned drawbacks and to provide a tool exchange or replacement system for machine tools having an advantage that an ample space is available for an operator thereof for his work in the machining area, in addition to an advantage that a rotation of a main spindle is utilized for replacement of a tool with another or for exchange of tools, removing the necessity to provide a drive which is employed exclusively for replacement of a tool with another or for exchange of tools. To achieve the aforementioned object, and according to the invention, a machine tool with a tool exchange system comprising a Z-slider slidable along a column, a spindle head supported by the Z-slider and rotatably housing a main spindle and a tool attachment/removal means therein, a magazine supporter, a magazine supported by the magazine supporter and rotatably supporting an elastic tool grip for gripping a tool, an elastic member elastically maintaining the magazine supporter at a machining position (pause position), a pair of gears and of which the one piece is arranged on the magazine and of which the other piece is rotatably supported by the main spindle, the pair of gears and being allowed to couple at the upper end of the stroke of the spindle head, and a first cam mechanism for operating the tool attachment/removal means, in response to vertical movement of the Z-slider, (as disclosed in EP-A-0088131) is characterised by the magazine supporter being rotatably supported by the column, and by a second cam mechanism for rotating the magazine supporter against the elastic member, in response to the vertical movement of the spindle head, thereby causing the elastic tool grip to shuttle between the machining position (pause position) and a tool exchange or replacement position. Various structures are available to realize the first cam mechanism. (i) The first cam mechanism in accordance with a first embodiment is provided a first cam arranged on the Z-slider or the spindle head and a first lever supported by the column and driven by the first cam to rotate the magazine supporter and the magazine, resultantly causing an elastic tool grip rotatably supported by the magazine to shuttle between the machining position (pause position) and the tool exchange or replacement position. (ii) The first cam mechanism in accordance with a second embodiment is provided a first cam arranged on the Z-slider and the magazine supporter rotatably supported by the column and which is driven by the first cam to rotate the magazine, resultantly functioning as the first lever for causing an elastic tool grip supported by the magazine to shuttle between the machining position (pause position) and the tool exchange or replacement position. (iii) The first cam mechanism in accordance with third and fourth embodiments are respectively provided a first cam arranged on the Z-slider and a first lever supported by the column and which is driven by the first cam to rotate the magazine (9), resultantly causing an elastic tool grip (10) rotatably supported by the magazine (9) to shuttle between the machining position (pause position) and the tool exchange or replacement position. A more detailed description will be presented below for 4 independent embodiments of the tool exchange or replacement system for machine tools in accordance with this invention, referring to the drawings tabulated below: Fig. 1 is a schematic drawing of a tool exchange or replacement system for machine tools available in the prior art in the machining position (wherein a tool is clamped with a main spindle and unclamped from a magazine), Fig. 2 is a schematic drawing of a tool exchange system for machine tools available in the prior art in the tool exchange or replacement position (wherein a tool is supported by a magazine and is not clamped with a main spindle but with a bevel gear), Fig. 3 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the first embodiment of this invention in the machining position (pause position), Fig. 4 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the first embodiment of this invention in the position slightly in advance of the tool exchange or replacement position, Fig. 5 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the first embodiment of this invention in the tool exchange or replacement position, Fig. 6 is a time chart illustrating the operation of a tool exchange or replacement system for machine tools in accordance with the first embodiment of this invention, Fig. 7 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the second embodiment of this invention (which is equivalent to Fig. 4 for the first embodiment), Fig. 8 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the third embodiment of this invention (which is equivalent to Fig. 4 for the first embodiment), and Fig. 9 is a schematic drawing of a tool exchange or replacement system for machine tools in accordance with the fourth embodiment of this invention (which is equivalent to Fig. 4 for the first embodiment). FIRST EMBODIMENT Referring to Figs. 3 to 5, the numeral 1 designates a column. In the drawings, the column 1 is illustrated in two independent parts including a pillar which slidably supports a Z-slider 3 and another part which rotatably supports the first lever 112 of the first cam mechanism 11 and the magazine supporter 7. The column 1 houses the Z-shaft 2, rotatably supports the first lever 112 of the first cam mechanism 11 and the magazine supporter 7, and supports one end of a spring 71 a which elastically maintains the magazine supporter 7 at the machining position (pause position) as illustrated in Fig. 3. The numeral 3 designates a Z-slider, and is vertically movable along the Z-shaft 2. The numeral 4 designates a spindle head, and is supported by the Z-slider 3. The spindle head 4 rotatably houses a main spindle 5 and a tool attachment/removal means 6 such as a drawbar etc. (not shown) having a collet (not shown) at the end thereof. An exemplary function of the tool attachment/removal means 6 is that a downward thrust applicable to the collet is effective to disconnect the tool 8 from the main spindle 5, although a collet connects a main spindle 5 and a tool 8 in an ordinary period. The magazine supporter 7 is rotatable in the direction of arrow A or C. The spring 71a of which the one end is supported by the column 1 pulls one end of the magazine supporter 7 to rotate in the direction of the arrow A. Thus, unless a first cam mechanism 11 works, the magazine supporter 7 stays at the machining position (pause position) illustrated in Fig. 3. Referring to Fig. 4, an upward move of the Z-slider 3 causes the first lever 112 of the first cam mechanism 11 to rotate in the direction of an arrow B, resultantly rotating the magazine supporter 7 in the direction of the arrow C. This rotation of the magazine supporter 7 causes the elastic tool grip 10 to move in the direction of an arrow D into the tool exchange or replacement position from the machining position (pause position). The magazine supporter 7 holds a magazine 9 and the elastic tool grip 10 supported by the magazine 9. The numerals 20 and 21 designate bevel gears. One 20 of the bevel gears is supported by the end of the main spindle 5 and is coupled with the other 21 at the tool exchange or replacement position, as shown in Fig. 5. An elastic tool grip 10 is designed to grip the tool 8 with the force of a spring. Thus, the elastic tool grip 10 is allowed to grip or ungrip the tool 8 only by pushing the elastic tool grip 10 to an arbour (not shown) of the tool 8 or by pulling the elastic tool grip 10 from the arbour of the tool 8. As will be described later, a second cam mechanism 12 works and the tool 8 is uncoupled from the main spindle 5 at the tool exchange or replacement position shown in Fig. 5. Thus, once the elastic tool grip 10 grips the tool 8, the first cam mechanism 11 ceases the function, and the elastic tool grip 10 stops the motion in the direction of the arrow D. However, the spindle head 4 continues the upward movement until the bevel gears 20 and 21 couple to each other, as shown in Fig. 5. During this upward movement of the spindle head 4, the tool 8 is drawn out of the main spindle 5. At this location, a rotation of the main spindle 5 causes the magazine 9 to rotate and to replace the tool 8 with another tool 8. After the tool 8 is replaced by another tool 8, the aforementioned steps are retraced in the reverse direction to return to the machining position (pause position). The numerals 11 and 12 are the first and second cam mechanisms, which are the subject matters of this invention. The numeral 11 designates the first cam mechanism, which consists of a first cam 111a supported by the spindle head 4, a first lever 112 supported by the column 1 and driven by the first cam 111a to rotate the magazine supporter 7, and a magazine supporter 7 elastically pulled by the contractive spring 71a in the direction of the arrow A, thereby having a function to shuttle the magazine 9 and the elastic tool grip 10 between the tool exchange or replacement position (pause position) shown in Fig. 3. The numeral 12 designates the second cam mechanism, which consists of a second cam 121 supported by the column 1, and the second lever 122 rotatably supported by the Z-slider 3. Once the Z-slider 3 rises until the second lever 122 contacts the second cam 121, the second cam mechanism 12 works, and the second lever 122 rotates in the direction of an arrow E, resultantly causing the tool attachment/removal means 6 to unclamp the tool 8 from the main spindle 5. In other words, the second lever 122 causes the tool 8 to be uncoupled from the main spindle 5 by some means such as pushing down a drawbar (not shown) of the tool attachment/removal means 6 for unclamping a collet (not shown). Referring to Fig. 6 illustrating a time chart and to Fig. 3, the operation of a tool exchange or replacement system in accordance with the first embodiment of this invention will be described below. When a machining finishes, the relative position of the magazine supporter 7, the magazine 9, the elastic tool grip 10 and the spindle head 4 is in the machining position (pause position) as shown in Fig. 3. In other words, during a machining, the elastic tool grip 10 is not located in the machining area where the tool 8 is located but is located at a higher position, the operator is given a wide machining area during the machining period. At the position wherein a machining finishes as shown in Fig. 3, the magazine supporter 7 is pulled by the spring 71a in the direction of the arrow A and is located at the machining position (pause position). As a result, the elastic tool grip 10 grips no tool 8. Referring to Figs. 4 and 6, during a short period after the Z-slider 3 begins to rise from the position illustrated in Fig. 3, the Z-slider 3 and the spindle head 4 alone rise, remaining the magazine supporter 7 unmoved. During this period, the relative position of the magazine supporter 7, the magazine 9, the elastic tool grip 10 and the spindle head 4 changes from the position shown in Fig. 3 to the position shown in Fig. 4. A contact of the first lever 112 with the first cam 111a causes the first lever 112 to rotate in the direction of the arrow B, allowing the first cam mechanism 11 to begin the operation. Namely, the magazine supporter 7 rotates against the spring 71a in the counterclockwise direction or in the direction of the arrow C, resultantly moving the elastic tool grip 10 in the direction of the arrow D until it arrives at the tool exchange or replacement position, where the elastic tool grip 10 is urged to the arbour of the tool 8 to be clamped thereto. Unless the magazine 9 rotates after the tool 8 employed for the last machining, the tool 8 employed for this machining is returned to the same tool holder of the magazine at which the tool 8 was held earlier. Referring to Figs. 5 and 6, the Z-slider 3 and the spindle head 4 continue the rising. A contact of the second lever 122 with the second cam 121 causes the second cam mechanism 12 to operate, and the tool attachment/removal means 6 works to remove the tool 8 from the main spindle 5. Since the tool 8 has already been gripped by the elastic tool grip 10 by this time, the tool 8 does not drop but is drawn out of the spindle, while it is held by the tool grip 10. Although the first cam mechanism 11 has terminated the operation and the magazine 9 has ceased the rotation by this time, the Z-slider alone continues rising until the bevel gear 20 supported by the lower end of the spindle head 4 and the level gear 21 supported by the magazine 9 are coupled to each other. At this time, the Z-slider 3 stops rising. Thereafter, the spindle 5 is rotated for the purpose to rotate the magazine 9 through the gears 20 and 21 and to bring another selected tool 8 to the position facing the main spindle 5. This rotation of the magazine 9 causes the tool 8 employed for the last machining to be moved to another place, while being held in the rotated magazine 9. The aforementioned steps have indexed another tool 8. After a new tool 8 is indexed, the aforementioned steps can be retraced in the reverse direction to return to the machining position. The Z-slider 3 is lowered from the position illustrated in Fig. 5 for uncoupling the gear 20 supported by the lower end of the spindle 5 from the gear 21 supported by the magazine 9 and finally for fixing the newly indexed tool 8 with the main spindle 5. Although the first cam mechanism 11 and the second cam mechanism 12 work almost simultaneously, the second cam mechanism 12 works first, causing the tool attachment/removal means to fix the tool 8 to the main spindle 5. Thereafter, the first cam mechanism 11 works to cause the sequential moves descrived below. Namely, the magazine supporter 7 is rotated by the spring 71a in the clockwise direction or in the direction of the arrow A to remove the elastic tool grip 10 from the arbour of the tool 8, before the magazine supporter 7 and the elastic tool grip 10 are returned to the machining position (pause position) as shown in Fig. 3. In the aforementioned manner, the first cam mechanism 11 finishes the operation. Thereafter, the spindle head 4 alone continues the downward travel until it arrives at the machining position (pause position). SECOND EMBODIMENT Referring to Fig. 7, a first cam 111b is supported by Z-slider 3 at a position located above the spindle head 4. A spring 71b is arranged between the column 1 and the magazine supporter 7 with extensible tension of which the direction is illustrated by the arrow A. Similarly to that of the first embodiment, the function of this spring 71b is to maintain the magazine supporter 7 at the machining position (pause position), unless the first cam mechanism 11 works. To realize this required function, the spring 71b is a compressive spring (normally exerting a tension which elongates the spring to urge the magazine supporter 7 in the clockwise direction). When the first cam mechanism 11 works, the first cam 111b urges the magazine supporter 7 against the spring 71b in the counterclockwise direction or in the direction of the arrow C. As a result, the elastic tool grip 10 moves in the direction of the arrow D toward the tool exchange or replacement position. The other operation is quite similar to that of the first embodiment. THIRD EMBODIMENT Referring to fig. 8, the difference between the third and fourth embodiments and the first and second embodiments is that the direction in which the first cam 111c or 111d moves in the case of the third or fourth embodiment is reverse to that in which the first cam 111a or 111b moves in the case of the first or second embodiment, in addition to that an additional link 72c or 72d is arranged between the first cam 111c or 111d and the magazine supporter 7. The additional link 72c of the third embodiment is allowed exclusively a linear move movable in the horizontal direction alone. The other operation is quite similar to that of the second embodiment. FOURTH EMBODIMENT Referring to Fig. 9, the difference between the fourth embodiment and the third embodiment is that the additional link 72d is of a rotary type in the case of the fourth embodiment, although that of the third embodiment is of a linear type. The aforementioned description has clarified that this invention has successfully provided a tool exchange or replacement system for machine tools having various advantages including (i) an ample space is available in the machining area during the machining period in the machining position, because no disturbing parts are available in the machining area during the machining period, (ii) a vertical move of the Z-slider allows the elastic tool grip to shuttle between the machining position (pause position) and the tool exchange or replacement position, and (iii) a rotation of the main spindle conducted at the tool exchage or replacement position allows an indexing of an arbitrary tool.

Claims: 1. A machine tool with a tool exchange system comprising a Z-slider (3) slidable along a column (1), a spindle head (4) supported by the Z-slider (3) and rotatably housing a main spindle (5) and a tool attachment/removal means (6) therein, a magazine supporter (7), a magazine (9) supported by the magazine supporter (7) and rotatably supporting an elastic tool grip (10) for gripping a tool (8), an elastic member (71a-d) elastically maintaining the magazine supporter (7) at a machining position (pause position), a pair of gears (20) and (21) of which the one piece (21) is arranged on the magazine (9) and of which the other piece (20) is rotatably supported by the main spindle (5), the pair of gears (20) and (21) being allowed to couple at the upper end of the stroke of the spindle head (4), and a first cam mechanism (12) for operating the tool attachment/removal means (6), in response to vertical movement of the Z-slider (3), characterised by the magazine supporter (7) being rotatably supported by the column (1), and by a second cam mechanism (11) for rotating the magazine supporter (7) against the elastic member (71), in response to the vertical movement of the spindle head (4), thereby causing the elastic tool grip (10) to shuttle between the machining position (pause position) and a tool exchange or replacement position.

Inventors: AKIYAMA, YOSHIHISA, ARAKI, HIROSHI, ISHII, HISAO, KAMADA, HIROSHI, NAGATOMI, TAKASHI MEZON-DO-NOA MOTOYOKOYAMA-522
Applicants: FANUC LTD.
Application year: 1987
Main classification: B23Q3
IPC codes: B23Q3