Tool transfer device for machine tools

Abstract: The invention provides a tool transfer device for machine tools capable of reducing the tool transfer time and also reducing the cost by eliminating the need for any driving source. In a tool transfer device for machine tools, having a tool magazine 10 set beside a spindle 6 on which a tool is mounted, and serving for accommodating and holding therein a multiplicity of tools so that the tools are directed perpendicular to an axis of the spindle 6, and a transfer pot 23 set on a spindle side of the tool magazine 10, and driven and moved by a horizontally moving unit 21 and a vertically moving unit 22, wherein a next-process tool T1 accommodated in the tool magazine 10 is taken out and transferred horizontally to a stroke end position P2 by the transfer pot 23, and the next-process tool T1 is tilted at the stroke end position P2 to a tool changing position p1 in which the next-process tool T1 is parallel to the axis of the spindle 6, the tool transfer device comprises tool tilting means (tilted cam member 38, tilting cam member 39) for tilting the next-process tool T1 to the tool changing position P1 by horizontal movement of the horizontally moving unit 21 to the stroke end position P2.

Description: BACKGROUND OF THE INVENTION The present invention relates to a tool transfer device for machine tools designed to transfer a next-process tool taken out from a tool magazine, in which a multiplicity of tools are accommodated and held, to a tool changing position by a transfer pot, according to the preamble of independent claim 1 and as known from document EP 0 319 611 A. In some machine tools equipped with a tool changer, in order to enable production for a variety of product types and automatic continuous operation, a rack type tool magazine for accommodating and holding therein a multiplicity of tools is disposed on one side of the machine body with the tools directed perpendicular to the axis of the spindle, while a tool transfer device is mounted for transferring a next-process tool from the tool magazine to a tool changing position in which the tool is positioned parallel to the axis of the spindle. As such a tool transfer device, there has generally been provided hitherto one having the following structure. That is, a transfer pot which is driven by a horizontally moving unit and a vertically moving unit is disposed on the spindle side of the tool magazine, and a next-process tool accommodated in the tool magazine is taken out and moved horizontally by the transfer pot, thereby transferred up to a stroke end position. At the stroke end position, the next-process tool is moved over by being once pulled out from the transfer pot and inserted into a tilting standby pot, and the tilting standby pot is tilted by a tilting device such as a cylinder mechanism so that the next-process tool is positioned to a tool changing position in which the tool is parallel to the axis of the spindle. Then, the next-process tool in this tool changing position and a process-completed tool in the spindle are automatically exchanged by the tool changer. However, in this conventional tool transfer device, which adopts the structure that the next-process tool, after once moved over from the transfer pot into the tilting standby pot, is tilted to the tool changing position by the tilting device, there are problems that a loss of tool transfer time is involved and that the cost increases relative to the additional provision of a driving source for the tilting operation. The present invention having been accomplished in view of these and other problems of the prior art, an object of the invention is to provide a tool transfer device for machine tools capable of reducing the tool transfer time and also reducing the cost by eliminating the need for any driving source. In order to achieve the above object, the present invention, as disclosed in independent claim 1, provides a tool transfer device for machine tools having a tool magazine set beside a spindle on which a tool is mounted, the tool magazine serving for accommodating and holding therein a multiplicity of tools so that the tools are directed perpendicular to an axis of the spindle, said tool transfer device having a transfer pot which can be set on a spindle side of the tool magazine, and driven and moved by a horizontally moving unit and a vertically moving unit, wherein a next-process tool accommodated in the tool magazine can be taken out and transferred horizontally to a stroke end position by the transfer pot and tilted at the stroke end position to a tool changing position in which the next-process tool is parallel to the axis of the spindle, wherein the tool transfer device comprises tool tilting means for tilting the next-process tool to the tool changing position by horizontal movement of the horizontally moving unit on linear rails to the stroke end position, the tool tilting means comprising a link mechanism for swingably coupling the vertically moving unit with the horizontally moving unit, and guide rails for tilting the vertically moving unit by horizontal movement of the horizontally moving unit to the stroke end position so that the next-process tool is positioned to the tool changing position. In a preferred embodiment, the transfer pot comprises a pair of upper portion and lower portion which are vertically movable relative to each other, wherein the tool is gripped by vertically moving the upper portion and the lower portion. In a further preferred embodiment, the tool magazine of the machine tool comprises a vertical path and a horizontal path for transferring tools, the horizontal path being provided near the vertical center of the tool magazine. In the tool transfer device according to the present invention, since the tool tilting means for tilting the next-process tool to the tool changing position by horizontal movement of the horizontally moving unit to the stroke end position is provided, the next-process tool can be tilted by making use of the driving force of the horizontally moving unit that transfers the next-process tool up to the stroke end position. Thus, the need for the driving source such as a cylinder mechanism can be eliminated, producing an advantage that a parts count cut and a cost reduction can be attained. Also, since the next-process tool is tilted directly from the perpendicular-to-spindle position to the parallel-to-spindle position with the driving force of the horizontally moving unit, there can be produced an advantage that the tool transfer time can be shortened as compared with the case where the next-process tool is once moved over from the transfer pot to the tilting standby pot, which contributes to a speedup in tool changing time. As the vertically moving unit is swingably coupled to the horizontally moving unit via the link mechanism, and the guide rails for tilting the next-process tool to the tool changing position as a whole of the vertically moving unit by horizontal movement of the horizontally moving unit to the stroke end position are provided. Therefore, there can be produced an advantage that the tool tilting means can be fulfilled in a simple structure without using any driving source and thus implemented with low cost. In the preferred embodiment, wherein the transfer pot is composed of upper portion and lower portion and the tool is gripped by vertically moving the upper portion and the lower portion, there can be produced an advantage that the need for axial movement of the tool in taking out the tool from the tool magazine can be eliminated so that a space saving relative to this unnecessity can be obtained. In the further preferred embodiment, wherein the horizontal path of the tool magazine is provided near the vertical center of the tool magazine, there can be produced an advantage that tool transfer distance can be shortened, as compared with the conventional case where the tool is once retreated to the upper end position of the tool magazine and then horizontally moved from this upper-end retreat position. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a horizontal type machining center equipped with a tool magazine; Fig. 2 is a schematic perspective view of a tool transfer device set up to the tool magazine; Fig. 3 is a schematic view showing a tilting operation of the tool transfer device; Fig. 4 is a schematic plan view showing the tilting operation of the tool transfer device; Fig. 5 is a schematic plan view showing an operation of tool tilting means of the tool transfer device; Fig. 6 is a schematic rear view of the tool tilting means; Fig. 7 is a perspective view of the transfer pot of the tool transfer device; Fig. 8 is a schematic plan view showing an operation of a second tool tilting means; Fig. 9 is a schematic view showing tool tilting means of a tool transfert device according to the present invention; and Fig. 10 is a schematic plan view showing an operation of the tool tilting means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinbelow, the present invention is described with reference to the accompanying drawings. Figs. 1 through 7 are views for explaining tool transfer devices for machine tools. Fig. 1 is a perspective view of a horizontal type machining center equipped with a tool magazine, Fig. 2 is a schematic perspective view of the tool transfer device set to the tool magazine, Figs. 3 and 4 are a schematic view and a schematic plan view, respectively, showing tilting operation of the tool transfer device, Figs. 5 and 6 are a schematic plan view and a schematic rear view, respectively, showing tool tilting means, and Fig. 7 is a schematic perspective view of the transfer pot. In the figures, reference numeral 1 denotes a horizontal type machining center (machine tool). In this horizontal type machining center 1, roughly referring to its construction, a rectangular cylindrical-shaped column 3 is set in the rear of a fixed bed 2 so as to be movable in an X-axis direction (right-and-left direction as viewed from the front), a saddle 4 is set in the front of the column 3 so as to be movable in a Y-axis direction (up-and-down direction), and a spindle head 5 is set on the saddle 4. A spindle 6 is rotatably inserted in the spindle head 5, and a tool T is mounted on the spindle 6. A machining table 7 is set in the fore portion of the fixed bed 2 so as to be movable in a Z-axis direction (back-and-forth direction), and two pallets 8a, 8b are set on the machining table 7 so as to be pivotable between a machining position and a standby position. In this horizontal type machining center 1, the spindle 6, while being driven into rotation, is moved in the X-axis and Y-axis directions, and moreover the machining table 7 is moved in the Z-axis direction, by which a workpiece placed on the pallet 8a positioned in the machining position is machined. During this machining process, a next-process workpiece is set to the pallet 8b positioned in the standby position. A tool changer 9 is set on one side of the column 3. This tool changer 9 is so structured that, as shown in Figs. 1 and 4, a changing shaft 12 is axially movably and rotatably held by a change driver 11 fitted to the column 3 and that a changing arm 13 is fixed at a fore end portion of the changing shaft 12. Tool gripper portions 14, 14 are provided at both end portions of the changing arm 13. The tool changer 9 automatically replaces a process-completed tool T positioned in a spindle-side tool changing position P with a next-process tool T1 positioned in a magazine-side tool changing position P1. More concretely, the changing shaft 12 rotates, and the gripper portions 14, 14 of the changing arm 13 grip the process-completed tool T and the next-process tool T1. In this state, the changing shaft 12 advances, pulling the process-completed tool T out of the spindle 6 and pulling the next-process tool T1 out of a later-described transfer pot 23, and subsequently the changing arm 13 rotates 180 degrees, retreating. Then, the next-process tool T1 is gripped by the spindle 6 while the process-completed tool T is gripped by the transfer pot 23, and the process-completed tool T is returned to a later-described tool magazine 10 by the transfer pot 23. Beside the tool changer 9 of the fixed bed 2, is provided a rack type tool magazine 10. This tool magazine 10 has a multiplicity (e.g., 120) of tools Tn accommodated and held in its rack body 11. The rack body 11 is generally box-shaped, having a rectangular frame body formed from a top wall 11a and a floor wall 11b coupled together by means of front and rear walls 11d, 11c, where in the rack body 11, the tools Tn are arranged in parallel toward a direction (X-axis direction) perpendicular to the axis of the spindle 6 (Z-axis direction). Also, between the tools Tn within the rack body 11, although not shown, are provided a vertical path for taking tools in and out, and a horizontal path for transferring tools to the tool changing position P1, the horizontal path being provided at the vertical center of the rack body 11. Each of the tools Tn has a cutting tool Tb such as a drill or an end mill fitted into a conical tool holder Ta. Each tool Tn is so set that the cutting tool Tb is positioned outside the machine while the tool holder Ta is positioned inside the machine (on the spindle side). A tool transfer device 20 is set on the inner side of the tool magazine 10. This tool transfer device 20 is made up of a quadratic-prism-shaped horizontally moving unit 21 which moves horizontally along the axis of the spindle 6 (Z-axis direction), a vertically moving unit 22 set to the horizontally moving unit 21 so as to be movable in the up-and-down direction (Y-axis direction), and the transfer pot 23 fixedly set to the vertically moving unit 22. Horizontal and vertical drivers are provided for the horizontally moving unit 21 and the vertically moving unit 22, respectively. The horizontally moving unit 21 is held to the top wall 11a and floor wall 11b of the rack body 11 so as to be movable via linear rails 25, 25. These linear rails 25 are so constructed that blocks 27, 27 fixed to the horizontally moving unit 21 are slidably engaged with two rails 26, 26 laid down on the top wall 11a and the floor wall 11b with guide rollers (not shown) interposed therebetween, respectively. The vertically moving unit 22 is made up of a longitudinal plate portion 22a confronting the front wall of the horizontally moving unit 21, and a horizontal plate portion 22b, where the horizontal plate portion 22b has the transfer pot 23 mounted thereon. The vertically moving unit 22 is held on the front wall of the horizontally moving unit 21 so as to be movable via linear rails 28, and the linear rails 28 are so constructed that blocks 30, 30 fixed to the longitudinal plate portion 22a are slidably engaged with two rails 29, 29 laid down on the front wall of the horizontally moving unit 21 with guide rollers interposed therebetween, respectively, like the foregoing case. The transfer pot 23 is so constructed that, as shown in Fig. 7, a pair of lower portion 33 and upper portion 34 are vertically movably held by two guide members 36, 36 and vertically driven by a cylinder mechanism 35. The lower portion 33 and the upper portion 34 have recessed portions formed therein so as to provide holder recesses 33a, 34a, respectively, at which the tool holder Ta is to be accommodated and gripped. The tool gripper portions of the transfer pot 23 are projected outward from outer-side end faces of the moving units 21, 22 so that tools can be taken out from the tool magazine 10 without axially moving the tools. Also, a tilting shaft 37 is fixedly inserted in the lower portion 33, and the tilting shaft 37 is held to the horizontal plate portion 22b so as to be pivotable between a perpendicular-to-spindle position and a parallel-to-spindle position. This tilting shaft 37 is pivotally biased to the perpendicular-to-spindle position by unshown biasing means. Then, as shown in Figs. 4 to 6, the transfer pot 23 is provided with a tilted cam member 38 constituting one of tool tilting means, and the tilted cam member 38 is fixedly mounted on the inner side wall of the transfer pot 23. Also, a tilting cam member 39 constituting the other of the tool tilting means is set at a site confronting the tilted cam member 38 a little short of the stroke end position P2, and the tilting cam member 39 is fixedly mounted on the machine-body side. The tilting cam member 39 is so structured that a cam follower 39c is rotatably held between a pair of upper-and-lower holder plates 39a, 39b. The tilted cam member 38 is composed of a pair of front-and-rear cam plates 38a, 38b, and the cam follower 39c is engageable between the cam plates 38a, 38b. As viewed along the back-and-forth direction, the tilted cam member 38 is located a little upper or lower than the tilting cam member 39, so that as the tilted cam member 38 is horizontally moved by the horizontally moving unit 21 to a position confronting the cam follower 39c, the vertically moving unit 22 moves the front-and-rear cam plates 38a, 38b downward or upward until the cam plates 38a, 38b are engaged with the cam follower 39c. Then, in this state, while the horizontally moving unit 21 moves to the stroke end position P2, the inner side face of the rear cam plate 38b makes sliding contact with the cam follower 39c and the transfer pot 23 pivots 90 degrees about the tilting shaft 37, thus tilting to the tool changing position P1 parallel to the axis of the spindle. Also, as the horizontally moving unit 21 moves backward from the stroke end position P2, the front cam plate 38a makes sliding contact with the cam follower 39c, thereby returning the transfer pot 23 to the perpendicular-to-spindle position. Next, functional effects of this device are described. In this tool transfer device 20, the horizontally moving unit 21 and the vertically moving unit 22 transfer the transfer pot 23 to the takeout position for the next-process tool T1. The transfer pot 23 takes out the next-process tool T1 from the rack body 11, and the next-process tool T1 is transferred to the horizontal path via the vertical path by the units 21, 22. From this point on, the horizontally moving unit 21 linearly transfers the next-process tool T1 horizontally to the stroke end position P2 (see arrows in Figs. 1 and 2). When the transfer pot 23 is linearly moved horizontally by the horizontally moving unit 21 so as to be brought to the position confronting the cam follower 39c of the tilting cam member 39, the vertically moving unit 22 moves vertically so that the front-and-rear cam plates 38a, 38b are engaged with the cam follower 39c. In this state, simultaneously when the transfer pot 23, moving horizontally, reaches the stroke end position P2, the transfer pot 23 pivots 90 degrees. As a result, the next-process tool T1 is located in the tool changing position P1 where the tool is parallel to the axis of the spindle 6. Then, the next-process tool T1 located at the magazine-side tool changing position P1 and the process-completed tool T located at the spindle-side tool changing position P are automatically exchanged by the above-described tool changer 9. As shown above the tilted cam member 38 is fixed to the inner side wall of the transfer pot 23, the tilting cam member 39 is fixed on the machine-body side before the stroke end position P2. Then, while the tilted cam member 38 is engaged with the tilting cam member 39 by horizontal movement of the horizontally moving unit 21 as well as vertical movement of the vertically moving unit 22, the transfer pot 23 is pivoted 90 degrees so that the next-process tool T1 is located at the tool changing position P1. Therefore, by making use of the thrust of the horizontally moving unit 21 that transfers the next-process tool T1 up to the stroke end position P2, the next-process tool T1 can be tilted to the tool changing position P1, so that the need for the conventional driving source can be eliminated, allowing a parts count cut and a cost reduction to be achieved. Also, since the next-process tool T1 is pivoted from the perpendicular-to-spindle position to the parallel-to-spindle position with the thrust of the horizontally moving unit 21, tool transfer time can be shortened as compared with the conventional case where the next-process tool is once moved over from the transfer pot to the tilting standby pot. This further contributes to a speedup in tool changing time. The tilted cam member 38 is fixed to the transfer pot 23, and the tilting cam member 39 which is to be engaged with the tilted cam member 38 to make the transfer pot 23 pivoted is fixedly set before the stroke end position P2. Therefore, the tool tilting means can be fulfilled in a simple structure without using any driving source. Also, the lower portion 33 and the upper portion 34 of the transfer pot 23 are moved vertically by the cylinder mechanism 35, by which the tool holder Ta is gripped. Therefore, the need for axial movement of the tool in taking out the next-process tool T1 from the tool magazine 10 can be eliminated, allowing a space saving to be realized resultantly. Further, since the horizontal path is provided near the vertical center of the tool magazine 10, the tool transfer distance can be shortened, as compared with the conventional case where the tool is once retreated to an upper end position of the tool magazine and then horizontally moved from this upper-end retreat position. Fig. 8 is a view for explaining a second tool tilting means. In this figure, the same reference numerals as in Fig. 5 denote the same or corresponding component members. The tool tilting means is made up of a tilted cam member 45 fixed to the inner side wall of the transfer pot 23, and a tilting cam member 46 fixed to the machine body side. A semicircular tilting cam surface 46a is formed at a fore end portion of the tilting cam member 46, and a linear-shaped linear cam surface 45a which makes sliding contact with the tilting cam surface 46a as well as a circular cam surface 45b which is curved round in continuation from the linear cam surface 45a are formed in the tilted cam member 45. Then, when the tilted cam member 45 is horizontally moved by the horizontally moving unit 21 so as to come into contact with the tilting cam member 46, the linear cam surface 45a makes sliding contact with the tilting cam surface 46a, the transfer pot 23 pivoting 90 degrees so as to be tilted to the tool changing position P1 in which the transfer pot 23 is parallel to the axis of the spindle. Also, as the horizontally moving unit 21 moves backward from the stroke end position P2, the circular cam surface 45b makes sliding contact with the tilting cam surface 46a while the linear cam surface 45a keeps in sliding contact with the tilting cam surface 46a, by which the transfer pot 23 is returned to the perpendicular-to-spindle position. The tilted cam member 45 is fixed to the machine inner side wall of the transfer pot 23, and the tilting cam member 46 is fixed to the machine body at a site short of the stroke end position P2. Then, while the tilted cam member 45 is engaged with the tilting cam member 46 by horizontal linear movement of the horizontally moving unit 21, the transfer pot 23 is pivoted 90 degrees so that the next-process tool T1 is located at the tool changing position P1. Therefore, the next-process tool T1 can be tilted to the tool changing position P1 by making use of the thrust of the horizontally moving unit 21, thus eliminating the need for the conventional driving source, so that the same effects as in the first device can be obtained. Further the transfer pot 23 can be tilted only by horizontal movement of the horizontally moving unit 21. Figs. 9 and 10 are views for explaining the tool tilting means according to the present invention. In these figures, the same reference numerals as in Figs. 3 and 4 denote the same or corresponding component members. A tool transfer device 50 is so constituted that a quadratic-prism-shaped horizontally moving unit 51 and a vertically moving unit 52 are formed independently of each other, and the vertically moving unit 52 is swingably coupled with the horizontally moving unit 51 via a link mechanism 53. The horizontally moving unit 51 is horizontally movably held to the rack body (not shown) via two linear rails 55. In the vertically moving unit 52, a vertically moving member 52b is disposed within a generally box-shaped unit body 52a so as to be vertically movable via two linear rails 54, and a transfer pot 23 is fixedly disposed on the vertically moving member 52b. Also, in the link mechanism 53, a first link member 53a pivotally held on the unit body 52a, and a second link member 53b fixed to the horizontally moving unit 51 are pivotably coupled with each other. Guide rails 55a, 55a bending inward of the machine are integrally formed at stroke end portions of the linear rails 55 so as to be connected thereto, and the unit body 52a is in sliding contact with and along the linear rails 55 and the guide rails 55a. As a result, simultaneously when the horizontally moving unit 51, linearly moving horizontally, reaches the stroke end position P2, the whole vertically moving unit 52 pivots 90 degrees along the guide rails 55a, and resultantly, the next-process tool T1 is tilted to the tool changing position P1 in which the next-process tool T1 is parallel to the axis of the spindle 6. In this tool transfer device 50 of this embodiment, the vertically moving unit 52 is swingably coupled with the horizontally moving unit 51 via the link mechanism 53, and the guide rails 55a are provided in order that the whole vertically moving unit 52 is tilted by horizontal movement of the horizontally moving unit 51 so that the next-process tool T1 is located at the tool changing position P1. Therefore, the next-process tool T1 can be tilted to the tool changing position P1 by making use of the thrust of the horizontally moving unit 51, thus allowing a parts count cut and a cost reduction to be achieved. This also allows the transfer time to be shortened, contributing to a speedup in transfer work.

Claims: A tool transfer device (50) for machine tools having a tool magazine set beside a spindle on which a tool is mounted, the tool magazine serving for accommodating and holding therein a multiplicity of tools so that the tools are directed perpendicular to an axis of the spindle, said tool transfer device having a transfer pot (23) which can be set on a spindle side of the tool magazine, and being driven and moved by a horizontally moving unit (51) and a vertically moving unit (52), wherein a next-process tool (T1) accommodated in the tool magazine can be taken out and transferred horizontally to a stroke end position by the transfer pot and tilted at the stroke end position to a tool changing position in which the next-process tool (T1) is parallel to the axis of the spindle, characterised by the tool transfer device (50) comprising tool tilting means for tilting the next-process tool (T1) to the tool changing position by horizontal movement of the horizontally moving unit on linear rails (55) to the stroke end position, wherein the tool tilting means comprises a link mechanism (53) for swingably coupling the vertically moving unit (52) with the horizontally moving unit (51), and guide rails (55a) for tilting the vertically moving unit (52) by horizontal movement of the horizontally moving unit (51) to the stroke end position so that the next-process tool (T1) is positioned to the tool changing position (P1). The tool transfer device for machine tools according to claim 1, wherein the transfer pot comprises a pair of upper portion and lower portion which are vertically movable relative to each other, wherein the tool is gripped by vertically moving the upper portion and the lower portion. The tool transfer device for machine tools according to claim 1, wherein the tool magazine comprises a vertical path and a horizontal path for transferring tools, the horizontal path being provided near the vertical center of the tool magazine.

Inventors: NAKAI MASATERU, WATANABE MICHIO, YAMAMOTO TATSUYA, NAKAI, MASATERU, WATANABE, MICHIO, YAMAMOTO, TATSUYA, Nakai, Masateru, Mori Seiki Co., Ltd., Watanabe, Michio, Mori Seiki Co., Ltd., Yamamoto, Tatsuya, Mori Seiki Co., Ltd.
Applicants: MORI SEIKI SEISAKUSHO KK, MORI SEIKI CO., LTD.
Application year: 2000
Main classification: B23Q3
IPC codes: B23Q3