DE2542017A1 - CUTTING STEEL RETURN DEVICE FOR CHIPPING MACHINES - Google Patents

Description

Düsseldorf-Oberkassel

Cutting steel retraction device for cutting machine tools

The invention relates to a cutting steel retraction device for cutting machine tools, whose cross slide carrying the cutting steel is driven by means of a feed spindle, which in turn is driven by a feed gear from
a feed motor is driven.

Just like NC lathes, modern heavy-duty lathes do not have any mechanical transmission links between the main drive and the transverse or _{feed slide 0} The feed movements are achieved by independent hydraulic or DC motors that drive via gears and threaded spindles are adhered to exactly and precisely,

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if corresponding position feedback units on the main drive and on the infeed axes are connected via control electronics stands. An infeed position control as a function of the main spindle rotation is precise enough to allow a To be able to cut an internal thread or an external thread. However, if the electrical power supply is interrupted, it will run the main spindle drive compared to the feed drive due to the vastly different mass inertia in one different time interval up to zero speed. If this happens during a thread cutting operation, it must under certain circumstances an expensive workpiece can be expected to be rejected.

In order to quickly return the cutting steel to such facilities, it is known according to German patent specification 867 934, a special steel holder on the thread cutting Put on the tool slide, which is held in the working position by an energized lifting magnet in the event of a power interruption, it automatically swivels downwards by a spring and is thereby brought out of cut. However, such a special steel holder cannot be used for normal roughing and finishing work, since it is rotatable The stored tool holder cannot be used for roughing work for reasons of stability. Also is with this construction There is no possibility of placing heavy steel holders on the steel holder slide or the cutting steel can be clamped in any position, which greatly restricts the support's work area.

In the German patent specification 969 841 an embodiment is described in which a also around a fixed Pivot point of swiveling steel holder through the pumping action of a hydraulic pump via a pressure piston with toggle linkage is held in working position. In the event of a power failure or in the event of an arbitrary pressure failure in the pump, a spring pulls the Steel holder from the working position. This is also a special steel holder that is not used for normal

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Filming can be used.

In the German patent specification 1 120 837 is a retraction device described for the cross slide carrying the cutting steel on lathes, the cutting steel holder by a live electromagnet is held in the working position. In this device is between the in the usual way actuatable feed spindle and the steel holder cross slide a spring-loaded, through a magnetic tooth coupling held and provided with an internal partial thread coupling sleeve arranged with a corresponding coarse thread one on the feed spindle and opposite it axially not displaceable but rotatably mounted, but per se rotationally fixed spindle bearing bushing is engaged. As soon as the power supply to the magnetic tooth coupling is interrupted in the event of a power failure the spring energy is released and the steel holder retracts.

All known systems are due to their very large dimensions not suitable for the steel holders or cross slides of carousel lathes. Another disadvantage of the known devices is that they are not or only with restrictions for cutting internal or external threads are suitable.

The invention is based on the object of a cutting steel retraction device to create that can be used for all heavy-duty lathes at the same time without the need for special tool slides, Special tool holders or special tools are required. The cutting steel retraction device should be used without impairing the usual thread cutting functions, both for cutting internal threads and for cutting with an external thread without the need for conversion.

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The cutting steel retraction device according to the invention is used to achieve this object characterized in that it has a retraction motor acting as an energy store, which can be connected to the feed gear via an intermediate gear in the event of a power failure.

Such a retraction device can immediately next to the Infeed or feed motor can be attached. Since this retraction device acts directly on the feed spindle, remains the cutting steel-carrying cross slide is unaffected in its size and shape, so that the device according to the invention can be provided on virtually any horizontal or vertical lathe.

Before thread cutting, the retraction motor is cut depending on whether an internal thread or an external thread is cut is to be switched on in the corresponding direction of rotation, for which a corresponding selector switch is provided. at In the event of a total power failure or any other signal, the retraction motor is switched to via the intermediate gear Brought drive connection with the feed gear so that the retraction motor then acts directly on the feed gear. Depending on the selected direction of rotation of the retraction motor, the cutting tool or lathe chisel is then over the infeed spindle pulled out of cut. The route of retreat depends on the one hand on the moment of inertia of the retraction motor and on the other hand on the inertia of the cross slide including the feed spindle and the feed gear.

To increase the moment of inertia causing the retraction, it is provided according to a further invention that a flywheel is attached to the output shaft of the retraction motor.

The intermediate gear is preferably a planetary gear with one driven by the retraction motor Sun gear and a freely rotatable

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running outer wheel with internal teeth, the one Brake is assigned, which holds the outer wheel in the event of a power failure.

In the following, an embodiment of the cutting steel retraction device according to the invention is based on the drawing Example of a center lathe described.

The center lathe a shown schematically in the drawing contains a cross or tool slide in the usual way 7, which carries a cutting tool holder 11 for fastening the cutting tool or lathe tool 9. The delivery of the cutting steel 9 takes place for the thread cutting process by means of the feed motor 3, which is driven by the drive pinion 12 the gear 10 of the feed spindle 8 drives. These infeed movements are in no way by the invention Cutting steel retraction device affected.

The cutting steel retraction device according to the invention comprises a retraction motor 1, on whose output shaft 13 a flywheel 6 is attached. On the output shaft 13 is the sun gear 14 of a planetary gear, which also has the internally toothed outer wheel 4 and through the basket 15 with each other having connected planet gears 2. These planet gears 2 are shaped by the basket 15 with the output the shaft 16 and the gear 17 which is in engagement with the gear 10 of the feed spindle 8.

Venn the internally toothed outer wheel 4 is not slowed down and can therefore rotate freely rotate when the pullback motor 1, the planet wheels 2 with empty so that no driving force to the gear 17 and the feed screw can be transferred from the engine 8. 1 If, however, in the event of a power failure, the spring-loaded brake 5 in the form of an electromagnetic clutch is effective in the sense that the internally toothed outer gear 4 is held, then this outer gear forms the so-called fixed gear of the planetary gear, so that when the sun gear 14 rotates the

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Turn planet gears 2 on the ring gear and move the output.

Before thread cutting, the retraction motor 1 is switched on depending on the type of thread to be cut (internal thread or external thread) switched on in a corresponding direction. Because the internally toothed outer wheel 4 is not normally braked is, there is no torque influence on the gear 10 of the feed spindle 8. In the event of a total power failure or by however, any other signal becomes the spring-loaded brake 5 de-energized, so that the retraction motor acts directly on the gear 10 in the manner described above. By the preselected motor rotation can thus be pulled out of the cutting steel 10 via the feed spindle 8. As already mentioned, the retraction path depends on the one hand on the moment of inertia of the retraction motor 1 together with the flywheel 6 and on the other hand, of the inertia of the cross slide 7 including the feed spindle 8 and the through the two Gears 10 and 12 formed from the delivery gear.

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Claims (5)

Claims Ti ff ■ **? f * "~ ^ ¹ " * * ^ g "^^ - » - —M ■ mma.mam ^ m . — Μ. «■» - -—> M - ^ m - » -. ■■ —-« ■ _ £ Π. / Cutting steel retraction device for cutting machine tools, whose cross slide carrying the cutting steel is driven by means of a feed spindle which is in turn driven by an infeed motor via an infeed gear, characterized in that it is a Energy storage acting retraction motor (1), which in the event of a power failure via an intermediate gear to the delivery gear (10, 12) can be connected. 2. Apparatus according to claim 1, characterized in that on the output shaft (13) of the retraction motor (1) Flywheel (6) is attached. 3. Apparatus according to claim 1 or 2, characterized in that the intermediate gear is designed as a planetary gear is, whose sun gear (14) is mounted on the output shaft (13) of the retraction motor (1) and its with External gear provided with internal teeth (4) rotates when the machine tool is operating properly, during the Basket (15) of the planetary gear (s) (2) with the feed gear (10, 12) is in drive connection, and that the Outer wheel (4) is assigned a brake (5) which acts on the outer wheel (4) in the event of a power failure. 4. Apparatus according to claim 3, characterized in that the brake (5) as an electromagnetically operated spring pressure brake is trained. 5. Device according to one of claims 1 to 4, characterized characterized in that the retraction motor (1) is assigned a selector switch for setting the direction of rotation. 709813/0439