SU804264A2 - Chuck for cutting fine thread - Google Patents

Description

(54) CARTRIDGE FOR CUTTING SMALL THREADS

one

The invention relates to the field of machine tools and can be used on aggregate machines.

According to the main author. St. 621507, a cartridge for cutting fine threads containing a mandrel with a tap and mounted in a sleeve with axial movement of a nut with threads of different pitch is known, the mandrel being located in the nut and made of two parts with thread of different pitch that can be moved relative to each other, the difference of which less than thread pitch ij.

However, the known design has some drawbacks, one of which is the relatively low quality of processing.

The purpose of the invention is to improve the quality of processing.

This goal is achieved due to the fact that the tap holder is provided with an axial torque limiter.

FIG. 1 shows the cartridge in the longitudinal section, in the initial position; in fig. 2 - chuck at the time of threading; in fig. 3 shows section A-A in FIG. one.

The cartridge contains a mandrel 1, the shank 2 of which enters the axial hole of the mandrel 3 and is fixed against rotation by key 4. Threaded parts. mandrels 1 and 3 are installed in the nut 5, and the thread pitch on the mandrel 1 is greater than the thread pitch on the mandrel 3 by an amount greater than the thread pitch of the metal bar. The nut 5 is mounted with the possibility of axial movement in the sleeve 6 and is fixed against rotation by the key 7. The sleeve 6 is installed in the hole of the conductor plate B and fixed by the bar 9. In the end part of the bar 9, a slot is made that goes into the annular groove of the mandrel 3. Shank 10 of the mandrel 3 enters with a key 11 into the hole of the spindle 12 of the rotational drive. In the end bore of the mandrel 1, a holder 13 is mounted with a tap 14 secured therein. The holder 13 is fixed against rotation relative to the mandrel 1 by a screw 15. In the transverse hole of the holder 13 there are balls 16 and a spring 17. In the holder 13 there is an annular groove in which the balls sixteen

The cartridge works as follows.

The rotation from the spindle 12 is transmitted through the mandrels 1 and 3 to the holder 13 with the tap 14. With the rotation of the mandrels 1 and 3, the nut 5 moves down the threaded parts of the mandrels. Due to the difference in pitch of the threads on the mandrels 1 and 3, the mandrel 1 is attached (Axial movement relative to the mandrel 3 with a feed pitch equal to the difference of the pitch of the threads on the mandrels, and the feed pitch of the mandrel 1 is greater than the pitch of the tap 14.

At the moment of contact of the tap 14 with the edges of the aperture of the workpiece 18, the process of tapping the tap begins, and the tap 14 is forced to be supplied by moving the mandrel 1 and the spring balls 16 to the holder 13. tap 14 due to self-drilling, and the balls 16 under the action of the movement of the mandrel 1 emerge from the annular groove in the mandrel 1. From the beginning of the reversal of the rotation of the spindle 12, the tap 14 is twisted out of the hole of the part 18, the mandrel 1 moves upwards, and the holder 13, due to the difference in the feeding step of the mandrel 1 and the tap 14, moves out of the mandrel slot 1 and after the tap 14 comes out of the hole of the part 18 is held in this position by the force of the spring 17 through the balls 16. Further removal of the tap 14 from the part 18 is achieved by axial movement of the mandrel 1 to its original position.

Claims (1)

Invention Formula Chuck for cutting small threads on the main ed. St. 621507, characterized in that, in order to improve the quality of processing, the tap holder is provided with a limited axial torque. Sources of information taken into account during the examination i. USSR Author's Certificate 621507, cl. In 23 G 5/00, 1977.