DE19747995A1 - Spindles of machining center e.g. for accommodating a machining tool or for transporting items to be processed - Google Patents

Abstract

Two separate chucks (4a,4b) are pivotally positioned on two parallel horizontal axles, each of them belonging to a pair of the vertical spindles which can be moved along a mutual guide axle. The spindles can either be used for the accommodation of a machining tool (14) or as transporting elements for the items (6) to be processed. A storage system for tools and materials consisting of various semicircular containers (20), open at one side, and a gripping device (23) is also part of the unit.

Description

The invention relates to a self-loading machining center according to the preamble of patent claim 1.

From DE 44 35 024 A1 a two-spindle drilling and milling machine is known, which has a horizontally rotatable Workpiece clamping device, the workpiece clamping elements are designed as workpiece grippers, workpieces feeds and discharges automatically from a conveyor belt.

This is for the provision and positioning of the workpieces in the area of the workpiece clamping device a conveyor belt with a complex transverse shifting device required, which has the cost advantage reduced compared to standard machines with separate robot loading. It also affects before Machine arranged conveyor belt the accessibility of the machine. In addition, productivity of a two-spindle machining center in large series production is often not sufficient - in comparison to conventional transfer lines.

A machining center is also known from DE 44 22 416 C1, the workpiece clamping device of which Workpiece gripper is formed and one workpiece automatically by one in a changing station per cycle Workpiece conveyor device feeds or discharges.

In the above-mentioned concept, a vertical was created based on self-loading lathes Main axis of rotation of the workpiece clamping device selected, because similar to lathes, only one individual workpiece is to be clamped on a workpiece clamping device. For machining centers in However, large series production is often intended to have several workpieces, for example on four sides of a clamping device be excited together. If, for self-loading, the lowering of the contact surfaces of a four-sided Workpiece clamping device should be possible from above via a workpiece provided, for reliable workpiece transfer, the four contact surfaces are clocked by 90 ° around a horizontal axis become. With a vertical axis of rotation, however, the contact surfaces must be on the side of those on a conveyor belt provided workpieces move up, causing an undesirable displacement of the workpieces during of the gripping process.

By installing additional axes of rotation of the workpiece clamping device in the above-mentioned concept Five-page editing will be possible. However, if this measure is only taken to To get an additional horizontal axis of rotation for a reliable self-loading function, it will anyway already very complex and unstable machine concept compared to conventional machining centers Robot loading economically uninteresting.

Based on the disadvantages of the prior art, a highly productive machining center should therefore be used be designed, whose work spindles are also suitable for the quick handling of workpieces. The tool magazine is designed to enable short access times with a high storage density. Next The magazine is also intended for simple construction without the use of additional tool changers Storage of workpieces provided on workpiece transport carriers can be used. This task will solved by the features of claim 1.  

According to the invention, two separate workpiece clamping devices are located on the new machining center assigned two independent double spindle slides to a common vertical slide. The Double spindle slides with the vertical cutting tools pointing upwards are on the front of the machine bed in pairs on a common horizontal linear axis.

At both ends of this guide axis there is a tool magazine with a vertical axis of rotation and stroke arranged. It contains at least one interchangeable segment, which is a semi-disc-shaped cassette with side open storage tongs for cutting tools and workpiece carriers.

In the pick-up mode, the spindles remove cutting tools or workpiece carriers from the Cassette and position it in the area of the workpiece fixtures.

The workpiece self-loading process is achieved in that the workpiece clamping devices work together via the are lowered on a workpiece carrier only by means of gravity and close the workpiece clamps of the workpiece clamping devices hydraulically. Four spindles can do this at the same time four workpiece transport carriers, each with preferably two stored workpieces for the Provide self-loading process and one by rotating the workpiece carrier by 180 ° Execute double changer function. In this way, a quick automatic workpiece change is also possible possible with multiple workpiece clamping devices.

In the tool and workpiece magazine, several cassettes can be stacked on one side on a shelf get saved. With a handling device arranged in the middle, the cassettes are moved only by one Combined lifting and rotating movement, exchanged without additional coupling or gripping processes.

In the lowest shelf position, the cassette for the machine operator is parallel to the main time Individual equipment accessible. In addition to a simple magazine structure, this concept is almost achieved a cost-neutral storage for raw and finished parts with automatic loading device.

The vertical, upward-facing position of the work spindles enables simultaneous use one workpiece turner per work spindle which removes workpieces from the workpiece clamping device, rotates by 180 °, for example, and reinserts it in a new clamping position in the workpiece clamping device. In this way, manual reclamping of workpieces from setup A to setup B is not necessary.

Simpler workpieces should be opened automatically by opening the workpiece clamp in the Workpiece clamping device falling onto an export slope swung in underneath and loosely on one Conveyor belt are removed. This reduces manual handling at the machining center similar to the transfer of raw parts for transfer lines.

In the following, the invention will be explained in greater detail on the basis of the exemplary embodiments shown in the drawings explained.  

Fig. 1 top view of the machining center.

Fig. 2 front view of the machining center.

Fig. 3 side view of the machining center.

The machining center has a machine bed ( 1 ), for example in cast construction, with two horizontal linear guides mounted on the top for the movement of the machine stand ( 2 ). The horizontal linear guides for the transverse movement of the two double spindle slides ( 3 a, 3 b) are provided on the front of the machine bed ( 1 ). Linear guides for the movement of the vertical slide ( 9 ) with the workpiece clamping devices ( 4 a, 4 b) are mounted on the machine stand ( 2 ).

By synchronously rotating the two identical workpiece clamping devices ( 4 a, 4 b), each with at least two clamped workpieces ( 6 ) on the vertical slide ( 9 ) about their parallel horizontal axes of rotation, it is possible to process at least three sides simultaneously on four identical workpieces.

For reasons of rigidity, a support bearing is provided for each of the two parallel horizontal axes of rotation on a counter-holder ( 8 ) on the vertical slide ( 9 ).

The workpieces ( 6 ) are held ready for automatic loading on a workpiece transport carrier ( 12 ), which is preferably designed with two storage locations, only by gravity. The workpiece transport carrier ( 12 ) has on the underside the same holding cone ( 13 ) that the cutting tools ( 14 ) have as a mechanical interface for the automatic change into the work spindle ( 15 ). Either four workpiece transport carriers ( 12 ) or four cutting tools ( 14 ) can be replaced in the four work spindles ( 15 ) of the machine. By moving the two double spindle slides ( 3 a, 3 b) on their guide axis, cutting tools ( 14 ) or workpiece transport carriers ( 12 ) are positioned in the machine work space below the workpiece clamping devices ( 4 a, 4 b). Lowering the workpiece clamping devices ( 4 a, 4 b) with open workpiece clamps ( 17 ) onto the workpieces ( 6 ) provided on the workpiece transport supports ( 12 ), closing the workpiece clamps ( 17 ) and lifting the workpiece clamping devices ( 4 a, 4 b) an automatic workpiece loading. By subsequently machining tools ( 14 ) instead of workpiece carrier ( 12 ) into the work spindles ( 15 ), the processing of the previously loaded workpieces ( 6 ) begins. After completion of the complete machining, workpiece transport carriers ( 12 ) are replaced in the work spindles ( 15 ). The workpiece transport carriers ( 12 ) are preferably each designed with two storage spaces. In this way, one finished workpiece ( 6 ) can be placed on the four free spaces of the workpiece carrier ( 12 ). By rotating the workpiece carrier ( 12 ) with the work spindles ( 15 ) with a vertical axis of rotation by 180 °, four new unworked workpieces ( 6 ) are positioned in the gripping area of the workpiece clamping devices ( 4 a, 4 b) and then clamped.

The workpiece clamping devices ( 4 a, 4 b) can also be unloaded by moving the two double spindle carriages ( 3 a, 3 b) into the left and right end positions of their guide axes and opening the workpiece clamps ( 17 ) and the finished workpieces ( 6 ) the force of gravity simply falls down without being again placed on a workpiece carrier ( 12 ). In order to be able to remove these workpieces ( 6 ) loosely from the machine work area, an execution bevel ( 16 ) is placed in the area below the workpiece clamping devices ( 4 a, 4 b) between the two double spindle slides ( 3 a, 3 b) before the workpiece clamps ( 17 ) are opened. swung in. The export slope ( 16 ) guides the workpieces ( 6 ) onto a conveyor belt ( 18 ) located on the floor in front of the machine.

Workpieces whose clamping position in the workpiece clamping devices ( 4 a, 4 b) must be changed during the complete machining can be reclamped automatically. For this purpose, instead of a workpiece carrier ( 12 ) or a cutting tool ( 14 ), preferably one pneumatic workpiece turner ( 19 ) is inserted into the four work spindles ( 15 ). The workpiece turner ( 19 ) in turn have the same receiving cone ( 13 ) as the cutting tools ( 14 ). The workpiece clamping devices ( 4 a, 4 b) are then positioned so that the contact surfaces of the workpieces ( 6 ) in the workpiece clamps ( 17 ) do not point downwards, but turned 90 ° to the side. The workpiece turner ( 19 ) in the work spindles ( 15 ) are now opened pneumatically. The required compressed air is supplied through the work spindles ( 15 ). The workpiece clamping devices ( 4 a, 4 b) now move down. Close the workpiece turner ( 19 ). Open the workpiece clamps ( 17 ) of the workpiece clamping devices ( 4 a, 4 b). The two double spindle slides ( 3 a, 3 b) move on their guide axis with the gripped workpieces ( 6 ) away from the workpiece clamping devices ( 4 a, 4 b). The workpiece turner ( 19 ) are rotated through 180 ° in the vertical work spindles ( 15 ). The double spindle slides ( 3 a, 3 b) move back. Close the workpiece clamps ( 17 ). Open the workpiece turner ( 19 ). The workpieces ( 6 ) are now positioned with the previously machined surfaces rotated by 180 ° in the workpiece clamping devices ( 4 a, 4 b), making it possible to machine previously inaccessible surfaces. If necessary, the workpiece clamping devices ( 4 a, 4 b) can have different workpiece clamps ( 17 ).

Cutting tools ( 14 ), workpiece transport carrier ( 12 ) and workpiece turner ( 19 ) are stored and made available with a common system. Preferably, each of the left and right ends of the linear guide for the double spindle slide (3 a, 3 b) located a shelf magazine, which consists of stacked half disk cartridge (20). The cassettes ( 20 ) have laterally open storage tongs ( 21 ) on the circumference, two storage tongs ( 21 ) always being arranged in parallel at the appropriate distance between two work spindles ( 15 ) of a double spindle slide ( 3 a, 3 b). A handling device with a rotatably mounted transport column ( 22 ) is located in the center of the stacked cassettes ( 20 ) of a shelf magazine. A carriage with a double-sided gripper fork ( 23 ) travels on the transport column ( 22 ), which takes cassettes ( 20 ) from the various rack positions and positions them at the spindle nose of the work spindles ( 15 ). The receiving cone ( 13 ) of the cutting tools ( 14 ), workpiece transport carrier ( 12 ) or workpiece turner ( 19 ) always points downwards. The transfer from the storage tongs ( 21 ) to the work spindle ( 15 ) takes place by the handling device rotating the half-disk-shaped cassette ( 20 ) into a position in which two receiving cones ( 13 ) are located exactly above the receiving cones of the working spindles ( 15 ) of a double spindle slide ( 3 a, 3 b) stand. The receiving cones ( 13 ) are then inserted into the receiving cones by lowering the half-disk-shaped cassette ( 20 ) and clamped in the work spindles ( 15 ). The cutting tools ( 14 ), workpiece transport carrier ( 12 ) or workpiece turner ( 14 ) are laterally pulled out of the storage tongs ( 21 ) of the half-disk-shaped cassette ( 20 ) by the linear feed movement of a double spindle slide ( 3 a, 3 b) in the direction of the machine center. The subsequent saving takes place in reverse order.

In the double-sided gripper fork ( 23 ) of the handling device, two half-disk-shaped cassettes ( 20 ) are preferably gripped opposite one another, as a result of which they complement one another to form a full circle. The cassette change takes place parallel to the main time while the work spindles ( 15 ) carry out a machining operation which takes longer than approx. 10 seconds. For this purpose, the active cassette ( 20 a) with the two empty storage tongs which are reserved for the two cutting tools ( 14 ) which are currently performing a machining operation, is placed on a rack space ( 24 ) whose level is below the level of the work spindles ( 15 ).

A cassette ( 20 ) is placed on a shelf space ( 24 ) by the handling device engaging receiving holes in the cassette ( 20 ) with locating pins in the shelf space ( 24 ). After the cassette on the receiving pins of the rack position (24) rests the double gripper (23) thereby further lowering of the handling device in turn receiving pins of the double gripper (23) can be pulled out of the space provided receiving bores in the cassette (20). As soon as the double gripper ( 23 ) is no longer in engagement with the stored active cassette ( 20 a), the transport column ( 22 ) of the handling device guides with the double gripper ( 23 ) and the second passive cassette ( 20 b) which is still located in the opposite gripper. a 10 ° rotation. The cassettes ( 20 ) have slots ( 5 ) in the inner area through which the gripper forks of the double gripper ( 23 ) can pass in the vertical direction after the 10 ° rotation. The slots ( 5 ) of all the cassettes ( 20 ) stacked one above the other are in the same position. The transport aisle ( 7 ) for cassettes ( 20 ) is located on the side opposite the shelf. The handling device now brings the passive cassette ( 20 b) into the desired transfer position in the upper ragal area in the transport lane ( 7 ) by means of a vertical movement. The opposite free gripper fork of the double gripper ( 23 ), which passes through the slots ( 5 ) in the stored cassettes ( 20 ) during vertical movement, is now positioned in the desired rack space ( 24 ) in the area of the new cassette ( 20 ). The transport column ( 22 ) of the handling device now performs the previous 10 ° rotation with the double gripper ( 23 ) in the opposite direction and completes the vertical movement started until the locating pins of the double gripper ( 23 ) engage in the locating holes of the new cassette ( 20 ) and in further course, the corresponding mounting holes of the cassette ( 20 ) are cleared from the mounting pins of the rack space ( 24 ). Now the transport column ( 22 ) rotates 180 ° with the double gripper ( 23 ), which completes the exchange of the passive cassette ( 20 b) with a new cassette ( 20 ). Then the double gripper ( 23 ) moves down, loads the active cassette ( 20 a) and makes the empty storage tongs ( 21 ) available to the double spindle slide ( 30 a, 30 b) for the tool transfer. In this way, an active cassette ( 20 a) and a subsequently required new cassette ( 20 ) are in stock in the double gripper ( 23 ) of the handling device. Cutting tools ( 14 ) and workpiece transport carriers ( 12 ) are preferably stored in different cassettes ( 20 ).

The machine operator can access the cassette parallel to the main time if a cassette ( 20 ) is placed so deep on an additional shelf space ( 24 ) located at the lower end of the transport aisle ( 7 ) that it subsequently follows with the level of the work spindles ( 15 ). running provision operation of the double gripper ( 23 ) did not collide. By means of suitable protective measures, this lowermost shelf space ( 20 ) can be partitioned off from the transport aisle ( 7 ), which means that complete cassettes ( 20 ) can also be removed during the main time.

Claims (3)

1.Machining center with two workpiece and tool magazines and with two workpiece clamping devices ( 4 a, 4 b) that can be moved on a machine stand ( 1 ) with workpiece clamps ( 17 ), which are designed as workpiece grippers for the machining of hanging workpieces, with the workpieces ( 6 ) are fed and discharged, characterized in that two separate workpiece clamping devices ( 4 a, 4 b) for at least two workpieces ( 6 ) are rotatably arranged next to each other on two parallel horizontal axes on a common vertical slide, and that four vertical ones pointing upwards Working spindles ( 15 ) are assigned in pairs to a workpiece clamping device ( 4 a, 4 b), and can be moved on a common guide axis and accommodate cutting tools ( 14 ) or position workpiece transport carriers ( 12 ) in the area of the workpiece clamping devices ( 4 a, 4 b) and, that a workpiece and tool magazine Consists of half-disc-shaped cassettes ( 20 ), which are stored as tools and workpiece changers, on one side of a shelf, and a rotatable double gripper ( 23 ) arranged in the center, the double gripper ( 23 ) being loaded on one side parallel to its axis of rotation in the transport lane ( 7 ) opposite the shelf. Cassettes ( 20 ) transported linearly and exchanged by a combined lifting and rotating movement. 2. Machining center according to claim 1, characterized in that a downward-pointing workpiece lead-out bevel ( 16 ) is arranged pivotably on the front and loosely falling out of the opened workpiece clamping devices ( 4 a, 4 b) falling finished workpieces ( 6 ) on a Floor provided workpiece conveyor belt ( 18 ) leads. 3. Machining center according to claim 1, characterized in that the work spindles ( 15 ) are equipped for receiving a rotatable workpiece turner ( 19 ).