Tool Support for Use in Machine Tools Particularly in Turning Machines

The present invention relates to machine tools in general, and more particularly to improvements in tool supports for use in turning machines, especially in turning machines of the type wherein the tool support is mounted on a slide and the workpiece is held in a rotary work spindle.

Many types of machine tools are provided with automatic tool changers which exchange tools without any supervision or manipulation by the persons in charge. As a rule, such machines are equipped with a tool magazine and the automatic tool changer or tool changers are designed to transport discrete tools between the magazines and the tool holder of the machine. Each tool changer normally operates in such a way that it transports a fresh tool during movement away from the magazine and returns a previously used tool during travel toward the magazine. Tool magazines and automatic tool changers are desirable and practical in large machine tools and in huge production lines but they are less practical or cannot be used at all in relatively small machine tools, for example, in connection with many types of automatic turning machines. The space requirements of a magazine and tool changer are normally such that these parts cannot be readily installed in, on or adjacent to a relatively small turning machine or an analogous machine tool. Moreover, tool magazines and automatic tool changers are not practical for use in machine tools wherein the tools must be exchanged at frequent intervals because the total time which is taken up for exchange of tools constitutes a substantial percentage of the time during which the machine tool is in actual use. This holds especially true when the tool magazine must be installed at a relatively large distance from the working station so that the tool changer must transport the tools along an elongated path. Still further, when the tools must be exchanged at frequent intervals, the likelihood of penetration of foreign matter into the sockets for tools or tool holders is quite pronounced. If a chip, shaving or another foreign particle happens to enter a socket, the tool holder or the tool which is thereupon inserted into the same socket is not held in an optimum position so that the configuration and/or finish of the workpiece is unsatisfactory. It is well known that drills, turning tools and other types of tools which are used in relatively small automatic turning machines must be interchanged at frequent intervals; consequently, inaccurate finish of workpieces due to penetration of foreign matter into the sockets for such tools of their holders is to be be expected if the sockets remain empty for prolonged periods of time or at frequent intervals. Therefore, all presently utilized automatic turning machines employ reciprocal tool carriages or indexible tool turrets which support holders for several material removing tools. It was also proposed to provide the turret or carriage of a machine tool with two or more rows of sockets for tool holders to thereby increase the overall number of tools which can be held in readiness close to the working station. Such mounting of tool holders in several rows renders it possible to treat a workpiece with two tools in a simultaneous operation, for example, to remove material by means of a turning tool and a borer.

A drawback of the just described machine tools is that the treatment of each type of workpieces necessitates a different setup of tools in the tool support, regardless of whether the tool support constitutes a turret or a carriage. Thus, whenever the machine has completed the treatment of a batch of workpieces and is to treat a batch of different workpieces, the tools in the tool support must be rearranged and/or replaced with different tools. This is due to the fact that, when the tools are mounted in a turret, the latter is merely movable in the axial direction of the work spindle. A tool carriage in presently known machine tools is movable in a direction at right angles to the axis of the work spindle. For example, when the tools are mounted in an indexible turret which is movable only axially of the work spindle, a turning tool which is to remove material from the front end face of a workpiece in the chuck of the work spindle cannot be used in such a machine tool because the turret would be unable to move the turning tool radially of the work spindle.

An object of the invention is to provide a novel and improved machine tool wherein the tool support can carry a substantial number of tools and tool holders and is mounted in such a way that it contributes significantly to versatility and to the output of the machine tool.

Another object of the invention is to provide a novel and improved tool support for use in turning machines and analogous machine tools wherein a large number of tools can be mounted and held in such a way that the distribution of tools is not dependent on the nature of the workpieces which are to be treated and that each of a large number of tools can be rapidly moved to a requisite position for feeding toward engagement with the workpieces.

A further object of the invention is to provide a tool support which can be mounted on a slide in a machine tool in such a way that it constitutes an inexpensive, compact and lightweight substitute for automatic tool changing systems of presently known design.

An additional object of the invention is to provide a tool support which can be mounted on many presently known machine tools without necessitating appreciable alterations in the design of such machine tools.

A further object of the invention is to provide a tool support wherein the tools and their holders can be conveniently grouped to further facilitate movements of selected tools into engagement with workpieces and to prevent interference by one type of tool when the workpiece is being treated by a tool of another type.

The invention is embodied in a machine tool, particularly in a turning machine, which comprises a frame, a work spindle rotatably mounted in a portion of the frame and having means for holding workpieces which rotate during engagement with tools, a slide including a first carriage which is reciprocably mounted in the frame and a second carriage which is reciprocably mounted on the first carriage, one of the carriages being reciprocable axially of the work spindle and the other carriage being reciprocable radially of the work spindle, and a tool support which is mounted on the second carriage and comprises several groups of sockets or other suitable receiving means for tool holders. The groups preferably form rows of coplanar receiving means and each such group is movable into at least one predetermined plane in which the tools in tool holders supported by the receiving means in the selected group are in an optimum position for engagement with a workpiece in the work spindle.

The tool support comprises a turret mounted on and indexible with respect to the second carriage about a second axis located in a plane including the axis of the work spindle. The turret is provided with at least two groups or rows of receiving means for tool holders which are disposed in two parallel planes spaced in the direction of the second axis from each other.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in conjunction with the accompanying drawing.

FIG. 1 is a fragmentary side elevational view of a machine tool having a turret-shaped tool support which is constructed and mounted in accordance with the present invention;

FIG. 2 is a plan view of the structure shown in FIG. 1, further showing a workpiece which is mounted in the work spindle and being treated by one of the tools whose holders are supported by the receiving means of the turret; and

FIG. 3 is a side elevational view of a second turret-shaped tool support.

FIGS. 1 and 2 illustrate a portion of a machine tool which comprises a frame 20 having a headstock 22 for a rotary work spindle whose chuck is shown at 24. This chuck supports a workpiece 41 which is rotated about a horizontal axis while in engagement with a material removing tool. The frame 20 is further provided with horizontal ways or guide means 42 extending at right angles to the axis of the work spindle and supporting the first or lower carriage 40 of a cross slide 38. The slide 38 further includes an upper or second carriage 36 which is movable along ways provided on the lower carriage 40 and extending in parallelism with the axis of the work spindle. The carriage 36 mounts a tool support 26 here shown as including a single polygonal turret 28 which is indexible about a horizontal axis normal to the axis of the work spindle. The means for indexing the turret 28 forms no part of the present invention. If is further clear that the illustrated octagonal turret 28 can be replaced with a hexagonal, pentagonal, etc., turret without departing from the spirit of the invention.

Each facet of the peripheral surface of the turret 28 is formed with a pair of receiving means in the form of radial sockets (such as the sockets 44 shown in FIG. 3) serving to receive the male portions of tool holders 30 each of which can carry a different material removing tool 32. The sockets of the turret 28 form two groups each of which includes a row or annulus of eight equidistant coplanar sockets so that the turret can support as many as sixteen tools at a time.

The shaft of the turret 28 is mounted in a bearing 34 which is mounted on top of the upper carriage 36. In addition to being indexible about its own axis, the turret 28 is movable axially of the work spindle in response to movement of the upper carriage 36 relative to the lower carriage 40, and radially of the work spindle in response to movement of the lower carriage 40, along the ways 42. This enables the person in charge to place each of the two rows or groups of tool holders 30 into at least one predetermined plane in which the respective tools are in an optimum position for engagement with and for removal of material from the revolving workpiece 41. The tools 32 in the outer row or group of tool holders 30 (i.e., in the lower row, as viewed in FIG. 2) are intended to remove material from the exterior of the workpiece 41. The tools 32a in the inner group or row of tool holders 30 (nearer to the bearing 34) are intended to remove material from the interior of the workpiece 41. The illustrated tools 32b in the outer row of tool holders 30 are conventional turning tools whose bits are shown as extending from the respective tool holders.

The aforedescribed mobility of the turret 28 (with reference to the carriage 36, with the carriage 36 relative to the carriage 40, and/or with the carriages 36, 40 relative to the frame 20) renders it possible to employ two or more adjacent tools in any one of the two rows simultaneously wih each other or to employ each tool independently of all other tools (including those which are immediately adjacent to the selected tool). Thus, the improved tool support 26 serves as a convenient, cheaper and more compact substitute for a conventional tool magazine of the type from which the tools can be removed one after the other for delivery to the tool support prior to engagement with a workpiece. An important advantage of the tool support 26 over such tool magazines is that it can operate without tool changers and also that the tools 32 in each of the groups or rows can be distributed at random rather than in a predetermined sequence in dependency on the nature of workpieces as is customary in conventional tool magazines.

In the position shown in FIG. 2, one of the tools 32b in the outer row is in the process of reducing the diameter of the foremost end of the workpiece 41. All of the tools 32b of the outer row are located in a plane in which each of these tools can be indexed into material removing engagement with the workpiece. The selected tool is thereupon fed by moving the upper carriage 36 and the turret 28 with reference to the lower carriage 40 or by moving the carriages 36, 40 and the turret 28 with reference to the ways 42. By moving the carriage 36 to the right, as viewed in FIG. 2, and by thereupon moving the carriages 36, 40 downwardly, as viewed in FIG. 2, the tools 32a of the inner row (nearer to the bearing 34) can be placed into a plane in which a selected tool can be moved into proper position for engagement with the workpiece 41 in response to indexing of the turret 28 by one or more steps. It will be seen that the tools 32 of the outer and inner row need not be distributed in dependency on the nature of workpieces and that any one of these tools can be moved into an appropriate position with reference to the workpiece 41 or any other workpiece which can be properly held by the chuck 24.

It is clear that the movements of the carriages 36, 40 and the indexing of the turret 28 can be controlled by a suitable programming system of any known design. The feature that the tools 32b for external treatment of workpieces are assembled in a second row reduces the likelihood that the tool or tools of one row would interfere with the treatment of a workpiece by one or more tools of the other row, or vice versa. As shown in FIG. 2, the tools 32a of the inner row are sufficiently remote from the tools 32b of the outer row so that they cannot interfere with the operation of the tool which is shown in material removing engagement with the workpiece 41. Analogously, when one of the tools 32a in the inner row is caused to move into material removing engagement with the workpiece 41, the tools 32b of the outer row are out of the way and permit unimpeded internal treatment of the workpiece. The leftmost tool 32a in the inner row of tools shown in FIG. 2 is sufficiently remote from the workpiece 41 and from the chuck 24 to permit removal of material by the tool 32b which is shown in engagement with the workpiece 41 all the way to the outer end face of the chuck as well as all the way to the bore of the workpiece. This is so despite the fact that the diameter of the leftmost part of the workpiece 41 greatly exceeds the diameter of its medium and rightmost parts. If the workpiece 41 is replaced with a smaller diameter workpiece, the likelihood that one of the tools 32a in the inner row would interfere with the operation of a tool 32b in the outer row is even more remote. Thus, the selected tool 32b of the outer row can be moved radially of the chuck 24 all the way to the axis of the smaller-diameter workpiece. If the configuration of a workpiece is such that a tool 32a in the inner row would possibly interfere with the operation of a tool 32a in the outer row, the socket behind the selected tool 32b of the outer row is simply left empty. With reference to FIG. 2, the holder 30 for the leftmost tool 32a of the inner row can be removed while the axially aligned tool 32b of the outer row removes material from the workpiece 41. This enables the tool 32b which engages the workpiece 41 to reduce the latter's diameter to one which only slightly exceeds the diameter of the bore in the workpiece. In the event that the workpiece 41 is replaced with a solid workpiece (without an axial bore), the selected tool 32b of the of the outer row can remove from such solid workpiece material all the way to the axis of the chuck 24, provided that the associated tool holder of the inner row is temporarily removed from its socket.

FIG. 3 illustrates a modified tool support 43 which constitutes a cylindrical turret having a cylindrical peripheral surface provided with two rows or groups of radially extending receiving means in the form of sockets 44 each of which can receive a portion of a tool holder. It will be noted that the sockets 44 of the two rows are staggered with reference to each other, as considered in the circumferential direction of the tool support 43. This renders it possible to place the two rows closer to each other and to thus reduce the axial length of the tool support. This tool support can be used in the machine tool of FIGS. 1 and 2 in place of the polygonal turret 28. The tool support 43 of FIG. 3 is particularly suited for use in relatively small turning machines or analogous machine tools.

The sockets 44 of at least one of the rows of sockets shown in FIG. 3 can be provided with groove-like extensions, or the turret 43 can be provided with tongues extending axially of and into the respective sockets 44. The sockets are then capable of receiving tool holders 30 in such a way that the tool holders are movable radially of the turret 43 but cannot rotate in their sockets. Suitable mechanisms can be provided to effect axial adjustment of tool holders in their sockets. Such types of sockets are particularly suited for reception of holders for tools 32 which are intended to remove material from the exterior of a workpiece. Referring again to FIG. 2, it will be noted that the tools 32b in the outer row of receiving means in the turret 28 extend beyond the front end face of the turret. This is desirable because the front end face of the turret cannot interfere with the feeding of the tools in the outer row toward the workpiece 41.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of machine tools differing from the type described above.

While the invention has been illustrated and described as embodied in a machine tool, especially a turning machine, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that from the standpoint of prior art fairly constitute essential characteristics of of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.