The body of a conventional machining center typically has a configuration which resembles that illustrated by FIG. 1. That is, the machining center has a work table which is supported on a machine base a for horizontal sliding movement along the X axis. The body, in addition to the base a, is also provided with a boxlike base b positioned adjacent the rearward side of the table. This base supports, on the upper end thereof, an upright column B which is slidably supported on the base b for horizontal movement along the Y direction which extends substantially perpendicular to the X direction. A tool spindle head assembly C, which mounts thereon the selected tool, is mounted on the front side of the column B so as to be vertically movable, such as along the axis Z, so that the tool can perform the desired machining operation on a workpiece mounted on the table A.
This conventional arrangement as diagrammatically illustrated by FIG. 1, has proven to require a complex and bulky structure. In addition, this arrangement results in undesirable forces being imposed thereon, specifically on the column B. That is, the upward thrust force imposed on the tool spindle during a cutting operation acts on the spindle head C, which is suspended at one end from the column B in a manner similar to a cantilever beam. Due to this upward thrust force and the cantilever effect, the column B hence has exerted thereon a large counter force which tends to resist the cutting thrust force, this counter force being imposed on the bottom of the column B at the front side thereof. Due to the substantial thrust force and counter force, the structure of the machine base b and column B have to be extremely heavy and massive in order to maintain the necessary high accuracy required by the machining operation. This in turn necessitates that the feeding devices also have a heavy and rugged construction. Further, the sliding surface provided between the column B and the base b is normally disposed in the vicinity of the lower end of the tool spindle, and hence the cutting chips often come into contact with this slidable surface, thereby requiring that the machine be equipped with an appropriate chip removal device to maintain the sliding surfaces free of harmful chips.
Accordingly, it is an object of this invention to provide a machining center, and in particular an improved body structure for a machining center, which improvement overcomes many of the above-mentioned defects as associated with conventional machining centers.
More specifically, according to the present invention, the improved machining center includes an upright boxlike housing structure which projects upwardly adjacent the rear side of the table through a substantial vertical extent. This housing defines an interior chamber therein in which is positioned the movable support for mounting a plurality of tools. The boxlike housing structure has a pair of opposed sidewalls which, at their front edges, have forwardly projecting protrusions which significantly overhang the table. A slide is slidably mounted on the upper surfaces of the housing structure and is movable horizontally in perpendicular relationship to the table movement. This slide, on the front end thereof, mounts a tool spindle head assembly for displacement along a vertical axis, whereupon the spindle head assembly can be positioned directly over the table but can also be moved rearwardly to permit access to the tools stored within the boxlike housing structure. For this purpose, the front wall of the boxlike housing structure has a substantial opening which extends therethrough and projects vertically up through the top wall thereof, so that rearward slidable displacement of the slide permits the spindle head assembly to be moved rearwardly through the opening into the interior chamber to provide access to the stored tools.
With the improved machining center of this invention, and specifically the improved housing structure, the overall machine housing can be of substantially lighter weight, while at the same time providing the necessary ruggedness and precision of machine performance. This arrangement also substantially eliminates the need for additional chip removal systems, except those associated with the table. Further, this arrangement provides substantial space for the tool storage and exchange systems, and at the same time permits tools to be readily accessed to and from this storage system to permit convenience and efficiency of use.
Other objects and purposes of the invention will be apparent to persons familiar with systems of this general type upon reading the following specification and inspecting the accompanying drawings.