Abstract:
The invention is a CNC machine tool, namely a CNC lathe, that includes a horizontal main spindle. The unfinished parts to be machined are supplied to the machine tool horizontally to the working compartment by a handling device integrated into the CNC control, and are then supplied via the handling device to a chuck that is to the horizontal main spindle. The machine tool according to the invention is particularly well-suited for small machining runs.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a CNC-controlled machine tool, especially a CNC-controlled lathe. 
   2. Background Art 
   Today, for loading and unloading machine tools, namely lathes, bar feeds with part catchers are also employed in addition to expensive portal loaders or robots. The portal loader or robot has to be newly adjusted upon each workpiece change. The bar feed is restricted by the passage (bore) and the spindle, and the removal of the finished parts is mostly effected through part catchers which cannot be employed with surface-sensitive workpieces. 
   From DE 33 29 266 A1, a CNC-controlled machine tool, namely a lathe, with horizontally operating main spindle is known, wherein a linearly movable gripper picks up workpieces from a conveyor and transports them into the processing region and from the processing region again to the conveyor. 
   DE 101 40 940 A1 describes a CNC-controlled machine tool, namely a lathe, with a vertically operating main spindle, wherein workpieces are conveyed from a conveyor to a liftable delivering device by means of a delivering device, and are transported from there into the processing region and again back to the delivering device and from there to the conveyor by means of a linearly movable main spindle. 
   From U.S. Pat. No. 6,634,265 B2, a CNC-controlled machine tool, namely a lathe, with horizontally operating main spindle is known, wherein a linearly movable gripper tool unit picks up workpieces from a deposition surface and transports them into the processing region and from there again to the deposition surface. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a machine tool that can still be used even with a small series run. 
   The invention allows for minimal and low-cost effort to convey workpieces, especially so-called bushing parts, even with smallest series run, into the processing space of a CNC machine tool, preferably a lathe. Here, the functionality of a CNC-controlled machine is included in order to allow a quick, flexible and low-cost solution of loading and unloading. Therein, considering standard components such as tool turrets and part catchers, minimizing the change-over times and the workpiece change times for automating the production is achieved, whereby also loading and unloading for smallest series run becomes cost effective. Thus, for example, with the application of the teaching according to the invention it is possible to change over the loading and unloading device to new dimensions of workpieces to be processed, such as bushing parts, with few manual manipulations within a short period of time, for example one minute. 
   For fast unloading, the normal workpiece catcher can be simultaneously be used for loading. If the workpieces should be treated gently due to the surface, thus, the reversal of the loading for removing workpieces is possible with low overhead, with finished part pick-up in the turret with little increase of the changeover time. 
   Therefore, the tool of the present invention can be modified to suit the demands of the customer. 
   Furthermore, adjustment is no longer needed upon diameter changes. On supply, a small adjustment is required, since here only a prismatic stop that has to be displaced and fixed, for example by means of winged screws. So called pressers formed as guide sheets do not have to be adapted upon diameter change. Gripper fingers are fast to be adjusted by means of adjusting screws. By the large stroke of the gripper especially formed as a pneumatic gripper, readjustment is only required upon a change that is greater than 10 mm. 
   The gripper in the turret is pre-adjusted by use of a monkey wrench at a manual chuck and actuated by means of spring force. 
   Additionally, the invention provides that the workpiece gripper is attached to swing arms (swing movements) and is linearly moveable with a slider. By the mechanic coupling of the rotary and linear movements with only one motor, the dynamic flow can be directed from a rotary movement to a linear movement and vice versa without stopping. Thereby, the temporal flow is shortened and the component cost is greatly reduced. 
   Advantageously, the slider unit can be universally used. The delivery of the workpieces is directed horizontally into the working space and optionally out of this working space. The blanks are fetched vertically from a magazine and horizontally fed to the processing space of the machine tool, namely a lathe. 
   Optionally, a palette station can be provided. Unloading finished parts is directed to a linear or continuous conveyor, which can be formed as a belt conveyor or palette conveyor. 
   The workpiece length is automatically detected and evaluated by the torque regulation integrated in the CNC control. Adjustment of the change of workpiece length is not required. This is particularly advantageous in smallest series runs. 
   If a number of workpieces, which are for example cylindrical on the outer surface, are provided on a supply distance, this series of blanks has to be stopped, separated and fixed at a delivery position for taking measurements, thereby providing isolation. The invention provides that this is only effected by linear movement, for example by means of a cylinder driven by pressure medium pressure, preferably pneumatic in nature, which is for example to be loaded alternatively on both sides by pressure namely pneumatic in nature. Herein, the assembly of the isolation is chosen such that adjustment is not required upon change of the diameter. The stroke pressure to the workpiece gripper is chosen such that all of the workpiece lengths of the specification of the loading device proceeds automatically without setup and adjustment. Thereby, quick change-over to new workpiece sizes is possible, and use of this loading means is also economical with the capability of small lot sizes. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention&#39;s preferred embodiments, together with further objects and attendant advantages, will be best understood by reference to the following description taken in connection with the following drawings in which: 
       FIG. 1  is a front perspective view of a machine tool formed as a CNC-controlled lathe wherein the handling device is in the delivery position in the processing space; 
       FIG. 2  is a rear perspective view of the lathe of  FIG. 1  wherein the handling device is in the take-over position at the magazine; 
       FIG. 3  is a close-up perspective view of the machine tool of  FIG. 1  and  FIG. 2 ; 
       FIG. 4  is a close-up perspective view of the slide table and the prism; 
       FIG. 5  is a perspective view of a swing and rotating unit formed as a rotating and linear unit with the gripper swung downwards; 
       FIG. 6  is a perspective view of the rotating and linear unit of  FIG. 5  with the gripper swung in horizontal plane; 
       FIG. 7  is a perspective view of a cutout representation of the rotating and swing unit according to  FIGS. 5 and 6 , and 
       FIG. 8  is a side elevational view of the transporter of  FIG. 1  and  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring first to  FIGS. 1 and 2 , the invention has particular application in a CNC-controlled lathe, which is substantially composed of a bench  1  and a slider unit  2 , which is movable in a direction Y or Z and X or V by a motor, respectively with a turret  3  that is CNC-controlled and driven by a motor, which includes a turret disc  4 . 
   The reference character  5  denotes a spindle box, while  6  represents a rack above which a gripper  7  formed as a pneumatic gripper is disposed. The gripper  7  is liftable by a motor in opposite directions T and S, respectively, on two guide bars  8  with their longitudinal axes parallel to each other and extending horizontally. For this purpose, a rotating and linear unit  9  is associated with the gripper  7 , which substantially has planetary gearing  10 , a drive motor  11  for example formed as a direct-current motor, a toothed belt pulley  12 , a rotating unit  13 , and a transverse beam  14  for disposing the gripper  7 . Through the drive motor  11  and the planetary gearing  12  and toothed belt (not shown), the rotating and linear unit  9  can be driven by a motor in the longitudinal axis direction of the guide bars  8 , thus in the direction T and S, respectively, on the one hand, but the rotating unit  13  can also be swung in vertical plane, thus in the direction A and B, respectively, by more than 180°, preferably by an angle of 270°, according to which part is fixedly braked, on the other hand. For the lifting movement in T and S, respectively, for example, the toothed belt (not shown) is guided over the toothed belt pulley  12 , which can be fixedly braked (be fixed), or the toothed belt pulley  12  is fixedly braked, thereby effecting a swing movement of the rotating unit  13  with the gripper  7  about the longitudinal axis of the planetary gearing  10  or the toothed belt pulley  12 , respectively. In this manner, workpieces to be processed can be picked up and transported or processed workpieces can also be deposited again, if needed, respectively, in the manner described below. 
   The lathe, as in the drawings, has a working space  15 , which can be encapsulated to the outside (not shown). Only a partition  16  can be seen in the drawing, which has an opening  17 , which is closable by a flap  18  swingably movable about a horizontal axis. The guide bars  8  are supported in the opening  17  such that the gripper  7  can transport gripped workpieces  19  through the opening  17  into the working space  15  and deliver them to a gripper  20  for example formed as a spring gripper, which delivers the picked-up workpiece  19  to the chuck  21  of a main spindle by a corresponding rotating movement and a displacement movement in the direction Y. The finished part is designated by the reference character  23 . The main spindle is designated by  20 . 
   As can be seen in  FIGS. 3 and 4 , the linear conveyor for example formed as a roller conveyor, which is driven by a motor or by gravity (e.g. chute), is designated by the reference character  24 , by which the workpieces  19  to be processed (blanks) are conveyed. By the linear conveyor  24 , the blanks  19  are fed to a supply device  25  described below in the direction C. At the end of the linear conveyor  24 , a slide table  26  with horizontal supporting plate is provided, which has two plate- or sheet-shaped pressers  27 ,  28  diverging from each other in an angle α of 60° with the longitudinal axes in the illustrated embodiment, which are each disposed continuously slidable in the direction E, F or G, H, respectively, by a motor in longitudinal slots  29 ,  30  of the slide table  26 , which are formed longer than these pressers  27 ,  28 . The supply device  25  has a one-piece box-shaped formation, below the slide table  26  of which a transporter  31  is disposed liftable/swingable in the direction K and L, respectively. The transporter  31  is substantially composed of tongue-shaped transport tongues  34 ,  35 , which are disposed in longitudinal slots  32  and  33 , respectively, parallel and spaced from each other, roughened on its surface areas each protruding from the longitudinal slots  32  and  33  or provided with toothing or corrugation  36 . The two transport tongues  34  and  35  and the pressure plates  27 ,  28  are driven in opposite directions by a lifting motor  37 . This lifting motor  37  can be formed by a piston-cylinder unit to be loaded by medium pressure, especially alternatively on both sides by pressurized air. At  38  and  39 , as can be seen in  FIG. 8 , two spaced, identical levers are disposed provided in pairs for each transport tongue  34  and  35 . The lever pairs  38  and  39  and the lever pairs of the other transport tongue  34  or  35 , respectively, are each drivable by a coulisse consisting of a continuous bolt  40  and  41  extending transversely to the lifting direction K-L and slot-shaped elongated holes  42  and  43 , respectively, disposed in projections provided at the ends of the transport tongues  34  and  35 , in which the bolts  40  and  41 , respectively, migrate, if a lifting displacement in the direction K or L, respectively, is effected. Therein, the levers  38  and  39 , respectively, swing about the axes  44  and  45 , respectively, which are associated with the lifting motor  37 , on the one hand, and about fixed axes  46  and  47 , respectively, associated with the slide table  36 , whereby the transport tongues  34  and  35  carry out a lifting displacement movement in the direction M or N, as in  FIG. 8 , respectively, and thereby lift blanks  19  situated on the slide table  26  and prevent them from a further forward movement in the direction C towards the pressers  27  and  28 , respectively, or advance them between these diverging pressure plates  27  and  28 . The axes  44 ,  45  are supported in elongated holes. Thereby, this part has three functions, namely a transport of the blanks  19 , an isolation action and positioning with respect to the pressure plates  27  and  28 , and a prism-like part  48 , which is movable in the direction O and P, respectively, by a lifting motor  49  to be loaded alternatively on both sides by medium pressure, such as by air pressure. The prism-like part  48  has corresponding to the angle that the pressure plates  27  and  28  form with their side wells facing each other, a corresponding recess  50 , into which the workpieces  19  to be processed are inserted upon lowering the prism  48 . They are then lifted off the slide table  26 , whereupon they are gripped by the gripper  7  swung downwards in the direction A and then swung upwards by 270° and subsequently transported in the direction S to the working space  15  of the lathe, where they are delivered to the spring gripper  20 , which delivers them in turn to the chuck  21  of the main spindle for processing. The movements of the pressure plates  27  and  28  are thus such that they press the blanks tangentially against the prism-like member  48 , while the longitudinal/lifting movement of the transport tongues  34 ,  35  of the transporter  31  is effected similarly to a sewing machine. Therein, the lifting stroke (e.g. tipping) over the lever mechanism  38 ,  39 ,  40 ,  41  ( FIG. 8 ) of the transporter  31  is achieved such that the transport tongues  34 ,  35  are lifted upon forward movement and are lowered upon rearward stroke. All of the drives as well as all of the lifting and swing movements can be included in a sequence control, such as in the CNC control of the lathe. 
   The torque monitoring allows the selection and starting of different NC processing programs, respectively, after determining the part length. Thus, an automatic production of part families is possible. Tolerances can be defined for the workpiece lengths in order to ensure rejection/deposition without processing. Thereby, increase of the production safety results. 
   Horizontal supply of the blanks  19  into the working space  15  of the lathe is provided. After complete processing, the chuck  21  is released such that the finished parts  23  drop or slide into a provided container via a chute or the like. They can be transported away in any other manner (not shown). However, with surface-intensive parts it is possible to take the gripper  20  of the turret  3  for transporting off the completely processed workpieces  23 , thus in turn delivering them to the gripper  7 , which then transports the completely processed workpieces  23  in the direction T and conveys them in appropriate manner to the same member  24  or another conveyer. This can occur by a linear or swing movement. It is possible to linearly move the rotary and linear unit  9  in the vertical position with gripper  7  directed downwards in the direction S to deliver the finished part there to a conveyer disposed next to the feed  24 . It is also possible to associate a further axis, for example a transverse axis, with the gripper  7  in order that the finished parts  23  can be conveyed on a parallel conveyor or in another manner to a conveyer disposed in an angle to the linear conveyer  24 . The supply of blanks  19  on the one hand and the removal of finished parts  23  on the other hand are then fully-automatically achieved. 
   The features described in the summary, in the claims and in the description as well as apparent from the drawing can be essential for the realization of the invention both individually and in any combinations.