Machining apparatus

A machining apparatus has a vertical support frame defining two machining stations spaced apart in a direction, holders in the stations for rotating respective workpieces each about a respective station axis, and a transfer device for loading rough workpieces into the holders and for taking finished workpieces out of the holders. A single machining tool can be shifted in the direction between one position engaging the workpiece in one of the stations and out of engagement with the workpiece in the other of the stations and another position engaging the workpiece in the other station and out of engagement with the workpiece in the one station.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide an improved machining apparatus.

Another object is the provision of such an improved machining apparatus that overcomes the above-given disadvantages, in particular that operates more efficiently, in particular by using the machining tools virtually continuously.

SUMMARY OF THE INVENTION

A machining apparatus has according to the invention a vertical support frame defining two machining stations spaced apart in a direction, holders in the stations for rotating respective workpieces each about a respective station axis, and a transfer device for loading rough workpieces into the holders and for taking finished workpieces out of the holders. A single machining tool according to the invention can be shifted in the direction between one position engaging the workpiece in one of the stations and out of engagement with the workpiece in the other of the stations and another position engaging the workpiece in the other station and out of engagement with the workpiece in the one station.

With a machining apparatus according to the invention, one machining tool can work with at least two workpiece holders. While the workpiece on the first holder is being processed, the already processed workpiece on the second holder can be exchanged for an unprocessed or rough workpiece. Since the machining tool must only traverse a very short path between the workpiece holders, this results in an extremely short time during which the machine is not actually working. With this system the workpiece holders are fitted with shaft-like or elongated workpieces. However, a one-ended chuck or headstock can be used. The machine frame is manufactured in a block-type construction, for example from a polymer resin concrete. However it can also be made as a cast or welded structure. Additional machining tools are provided for with an advantageous embodiment, so that four-axis processing can be done at each of the workpiece holders, as needed.

SPECIFIC DESCRIPTION

As seen inFIG. 1shows a machining apparatus1with two vertical workpiece holders arranged next to each other for processing of rotationally symmetrical elongated rough workpieces into finished workpieces5′. The apparatus1comprises a rigid-form machine frame with a vertical side wall2. Respective chucks or headstocks3and4that which are spaced from one another in a horizontal direction D. Respective tailstocks14and14′ are aligned with along respective axes10and10′ with the headstocks3and4. The headstocks3and4are normally stationary, but the tailstocks14and14′ can move vertically on respective rails or guides carried on the support wall2.

A machining unit8carrying tool9, here a grinding disk centered on and rotatably driven about a vertical axis midway between the axes10and10′ is provided between the machining stations18and19defined by the workpiece holders3,14and4,14′. This unit8is horizontally shiftable on guides16on a slide or carriage15in turn vertically shiftable on guides or rails17on the side wall2. Thus the tool9can be moved horizontally between the two machining stations and vertically along the stations18and19. Thus workpieces5can be processed by lengthwise, milling, grinding or oscillating grinding action.

The tool9is only moved in the direction D through a very short distance between its position working on the workpiece5in the one station18and its position working on the workpiece5in the other station19, or vice versa. Thus time wasted during switchover from machining one workpiece and machining another workpiece is very short. A controller26is connected to unillustrated actuators to effect this movement.

The rough workpieces5are supplied to the machining apparatus1on conveyer belts20. Thence they are gripped by workpiece transport devices6and7and moved through openings or ports11in end walls12and inserted into the workpiece holders3and4. The controller26is also connected to these transport devices6and7so that as one workpiece5is being processed in the first work position18, the already processed workpiece5′ in the second work position19can be exchanged for an unprocessed workpiece5. In an advantageous embodiment, the openings11in the end walls12are situated above a plane13at which actual machining takes place inside the machine1. Thus escape of coolant or shavings thrown off by the spinning tool9and workpiece5through the ports11is prevented.

FIG. 2shows a machining apparatus1according toFIG. 1with additional machining tools21and21′ that can move along horizontal guide rails24on respective slide frames23. In turn the frames23can move along the vertical wall2on vertical guide rails25. Thus, if necessary, four-axis machining is possible at each of the workpiece holders3,4. For example, the tool9can be a roughing tool and tools22smoothing or finish tools.

InFIG. 3, machining apparatus1is shown with horizontal holders, that is the direction D is vertical and axes10and10′ are horizontal. Otherwise this arrangement generally corresponds to that ofFIG. 1. Here, however, the workpieces5are fed in at one end of the machine by the conveyor belts20and also extracted there. The machining assembly8moves in the vertical direction along guide-rails16on the frame15.