Drilling assembly for panel milling and drilling machines

Abstract: The present invention relates to a drilling assembly (1), specifically designed for panel milling and drilling machines, comprising a plurality of mandrels (2) for performing a vertical drilling and mandrel (3) for performing a horizontal drilling. The main feature of the invention is that each of said vertical drilling mandrels comprises a slotted shaft (10,40) which is slidably engaged with a driving gear (11,13). The slotted shaft of each said vertical drilling mandrel is coupled, at the bottom thereof, to a drill holding mandrel (17) and, at the top thereof, to an expanding piston (20) for removably locking the drill holding mandrel at a lowered working position.

Description: BACKGROUND OF THE INVENTION The present invention relates to a drilling assembly, specifically designed for panel milling and drilling machines. As is known, panel milling and drilling machines conventionally comprise a drilling assembly, including a plurality of mandrels for performing a vertical drilling and mandrels for performing a horizontal drilling, said mandrels being very complex construction-wise since they must perform a series of intricate movements for assuming their proper operating positions. Another problem is that of the location stability of the mandrels which, in the prior art machine, (see, for example, DE-19829814-A), is very difficult to achieve. Thus, prior machines of the above mentioned type frequently provide a poor machining. SUMMARY OF THE INVENTION Accordingly, the aim of the present invention is to overcome the above mentioned drawbacks, by providing a drilling assembly, specifically designed for panel milling and drilling machines, allowing to firmly and safely locate the operating mandrels thereof, thereby providing a very good machining quality. Within the scope of the above mentioned aim, a main object of the present invention is to provide such a drilling assembly including very simple means for locking the operating mandrels in their set operating positions. Another object of the present invention is to provide such a drilling assembly which, owing to its peculiar constructional features, is very reliable and safe in operation. Yet another object of the present invention is to provide such a drilling assembly which can be easily made starting from easily available elements and materials and which, moreover, is very competitive from a mere economic standpoint. According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a drilling assembly specifically designed for panel, milling and drilling machines, comprising a plurality of vertical drilling mandrels and horizontal drilling mandrels, characterized in that each said vertical drilling mandrels comprises a slotted shaft slidably engaged with a driving gear. The slotted shaft, moreover, is coupled, at a bottom portion thereof, to a drill holding mandrel and, at a top portion thereof, to an expanding piston for removably locking the drill holding mandrel at a lowered working position thereof. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of a drilling assembly specifically designed for panel milling and drilling machines, and being illustrated, by way of an indicative, but not limitative, example in the figures of the accompanying drawings, where: Figure 1 is a schematic exploded perspective view illustrating a vertical drilling mandrel; Figure 2 illustrates a further schematic exploded perspective view of a horizontal drilling mandrel; Figure 3 is a cross-sectional view illustrating a vertical drilling mandrel in a rest condition thereof; Figure 4 illustrates a vertical drilling mandrel in an working position thereof; Figure 5 is a schematic cross-sectional view illustrating the expanding piston associated with the vertical drilling mandrel, in a rest or stand-by condition thereof; Figure 6 is further cross-sectional view illustrating the expanding piston and vertical drilling mandrel in a working position thereof; Figure 7 is a further schematic cross-sectional view illustrating the horizontal drilling mandrel in a rest or stand-by position thereof; Figure 8 illustrates the horizontal drilling mandrel in a working position thereof; and Figure 9 is a cross-sectional view illustrating a detail of the horizontal drill holding mandrel. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the number references of the above mentioned figures, the drilling assembly, specifically designed for panel milling and drilling machines, which has been generally indicated by the reference number 1, comprises a plurality of vertical drilling mandrels 2 and at least a horizontal drilling mandrel 3. Each vertical drilling mandrel 2 comprises, in turn, a slotted or splined shaft 10, which is slidably engaged inside a driving gear 11, the latter being coupled to a kinematic gear chain 12 taking the drive from a driving motor (not specifically shown). The splined or slotted shaft 10, which can slide with respect to the driving gear 11, is coupled, at its bottom portion, through a vertical shaft or spindle 15, which can turn inside a first bushing 16, with a drill holding mandrel 17. At the top thereof, the splined or slotted shaft 10 is coupled to an expanding piston 20 which, by a piston rod 21, is coupled to a driving cylinder 22 provided for driving the vertical drilling mandrel. The expanding piston is adapted to slide through a first vertical sleeve 30 which, at the bottom portion thereof, on the side of the driving gear 11, is provided with an enlarged portion 31. As shown, the expanding piston 20 comprises a piston body 32 coupled to the splined shaft, ending with a conical tapering portion 33 encompassing a guide 34 in which a counter-conic element 35 can be engaged, which counter-conic element is coupled to the piston rod 21 and delimiting, in combination with a further conical tapering portion 33, a groove in which a split ring 37 is engaged. Thus, as the vertical drilling mandrel is caused to be lowered, said counter-conic element 35 will provide a pushing force. As the expanding piston 20 is arranged at the enlarged portion 31, the split ring 37 will be radially expanded, to engage in a locked manner in the shoulder 38 defined between the first sleeve 30 and said enlarged portion 31. Said locking will prevent the pushing force affecting the vertical drilling drill, to cause the vertical mandrel to be raised again during a drilling operation, thereby said mandrel will be firmly held in its set position. At the completion of the drilling operation, on the other hand, the mentioned mandrel can be raised again since the piston rod 21, by recovering the counter-conic element 35 to its starting position, will allow the split ring 37 to radially contract, thereby allowing in turn the expanding piston 20 to be raised again. The horizontal drilling mandrel, as shown, is provided with a second slotted or splined shaft 40, also slidably engaged with one of the driving gears, indicated by the reference number 13, included in the provided gear chain. Said second slotted or splined shaft 40 is coupled, at the top thereof to a coupling body 41, for coupling to a second piston rod 42 in turn connected to a horizontal drilling cylinder 43. At the bottom thereof the splined shaft 40 is coupled to a driving shaft 44 which can turn inside a second bushing 45 which, at the bottom thereof, is coupled to a horizontal drilling head 46. The bushing 45 is provided with a flat portion 47 therewith is engaged a tempered pin 48 provided for stopping the lowering movement of the horizontal drilling mandrel, thereby allowing a very stable position to be obtained. The horizontal drilling head 46, as is shown in a more detailed manner in Figure 9, is provided with a conical gear 50, coupled to the driving shaft 44, and meshing with a second conic or bevel gear 51. The latter is keyed on a horizontal drilling mandrel 52, which is rotatably supported by the drilling head and is provided with an end-piece 53 which is in turn supported by a supporting nut 54. With the above disclosed arrangement, as the horizontal drilling mandrel is lowered to a working position thereof, the engagement of the pin 48 and top end portion of the cut-out 47 will provide a very stable coupling eliminating any clearances, thereby the machine can perform a very accurate machining. Moreover, the engagement of the pin and of the cut-out will operate as a guide element to prevent any rotary movements against the vertical axis of the horizontal drilling head. From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects. In particular, the fact is to be pointed out that a drilling assembly has been provided which, by very simple means, allows to firmly locate at their working positions both the vertical mandrels and the horizontal mandrels. The invention as disclosed is susceptible to several modifications and variations, all of which will come within the invention scope, as defined in the appended claims. Moreover, all of the constructional details can be replaced by other technically equivalent elements. In practicing the invention, the used materials, as well as the contingent size and shapes, can be any, depending on requirements.

Claims: A drilling assembly, specifically designed for panel milling and drilling machines, comprising a plurality of vertical drilling mandrels (2) and horizontal drilling mandrels (3), whereby each said vertical drilling mandrels (2) comprises a slotted shaft (10) slidably engaged with a driving gear (11) and that said slotted shaft is coupled, at a bottom portion thereof, to a drill holding mandrel (17), characterized in that said slotted shaft is coupled at a top portion thereof, to an expanding piston (20) for removably locking the drill holding mandrel at a lowered or working position thereof. A drilling assembly, according to the preceding claim, characterized in that said slotted shaft (10) is coupled, at a bottom portion thereof, to a shaft (15) which is rotatably supported by a first bottom bushing (16) also supporting said drill holding mandrel (17). A drilling assembly, according to one of the preceding claims, characterized in that said expanding piston (20) comprises a piston body (32) coupled to said slotted shaft and engageable in a first top sleeve (30), and that said expanding piston is coupled, at a top portion thereof to a piston rod (21) in turn coupled to a first driving cylinder (22). A drilling assembly, according to claim 3, characterized in that said sleeve (30) is provided, at a bottom end portion thereof, with a locking enlarged portion (31) for locking said expanding piston. A drilling assembly, according to one of the preceding claims, characterized in that the expanding piston comprises a piston body coupled to the slotted shaft and ending with a conical tapering portion (33), and that, inside said conical tapering portion is provided a guide seat of a counter-conic element (35) delimiting, with said conic tapering portion, a groove in which a split ring (37) is engaged, said split ring being adapted to be radially expanded in said enlarged portion (31) under a pushing by said piston rod, a pulling force on said counter-conic elment causing a partial disengaging of the counter-conic element from said conic tapering portion, thereby causing said split ring to be radially contracted and disengaged from said enlarged portion. A drilling assembly, according to one of the preceding claims, characterized in that said driving gear meshes with a gear chain coupled to a motor. A drilling assembly, according to one of the preceding claims, characterized in that said horizontal drilling mandrel (3) is provided with a slotted shaft (40) coupled, at a bottom portion thereof, to a drive shaft (44) rotatably supported inside a second bottom bushing (45) supporting the horizontal drilling head, and that the second bottom bushing is provided with a flat surface portion and therein is engaged a tempered pin (48) designed for operating as a limit element for the locating, during a working operation, of said horizontal drilling mandrel. A drilling assembly, according to claim 7, characterized in that the second slotted shaft (40) is coupled, at the top portion thereof, to a body in turn coupled, through a second stem (42), to a horizontal drilling mandrel driving cylinder (43). A drilling assembly, according to one of the preceding claims 7 or 8, characterized in that said slotted shaft (40) is coupled to a first conical gear (50), rotatably supported by said head and operatively coupled to a drill holding mandrel (52).

Inventors: ALBERTI LUIGI, ALBERTI, LUIGI
Applicants: ALBERTI VITTORIO SPA, ALBERTI VITTORIO S.P.A.
Application year: 2000
Main classification: B23Q1
IPC codes: B23Q1, B23Q5, B23B39