CS242484B1 - Milling fixture for starting and ending internal threads - Google Patents

Abstract

The invention relates to a milling device for cleaning the beginnings and ends of internal threads. The invention solves the problem of removing the profile of a part of the first and last thread by milling, even in discontinuous holes. The essence of the invention is the eccentric placement of working tools - milling cutters, with the possibility of extending them to the required depth of cut. The invention can be used for cleaning the beginnings and ends of internal threads, as well as for milling helical grooves in mechanical engineering.

Description

BACKGROUND OF THE INVENTION The present invention relates to a milling cutter for internal thread end milling and end milling, which has to be cleaned for nuclear reactor core program products.

Up to now, the threading of the ends and ends of the internal threads has been carried out in two ways, namely: manually by means of milling cutters and milling means.

The disadvantage of the manual contamination method is the strenuousness and relatively high workload of the operation, and this method does not guarantee the quality of the contamination works.

The second type of pollution uses a milling tool driven by an air drill through a worm gear and bevel gear. The entire mechanism is housed in a cylindrical body that has three cylinders extending circumferentially, one of which is ex- tremely retractable to the internal diameter of the thread.

The fixture is of a labor-intensive construction and its clamping elements require a very precise and rigid fit as it is a milling fixture. Each manufacturing part of the clamping part manifests itself by shearing the cutting tool - the milling cutter, which affects the quality of the machined surface. Another disadvantage of this device is that the clamping surface between the jig and the cleaned thread is very small. Due to the cutting forces of the milling, the surface quality of the clamping rollers is reduced or reduced. pushing the small thread diameter of the nut. The advantages of the milling cutter for cleaning the start and end of the internal threads of the invention lie in a simple, low-cost construction, with a rigid assembly tool, as the guide thread of the support sleeve is made to a control gauge for the thread. The large contact area of the workpiece with the fixture ensures low specific pressures. It is possible to clean both ends of the thread in the through hole in one setup.

In the accompanying drawing, there is a side view of a milling device according to the invention.

The milling fixture consists of a support sleeve 1 in which the eccentrically mounted cylinder 2 is rotatably axially delimited by the flanges 3. In the cylinder 2, the shaft 4 is again eccentrically housed in the sliding sleeves 5. Two mills 6 are clamped on the shaft 4.

The distance B of the milling cutter 6 is precisely determined by the function of the milling cutter. The construction A provides a distance between the shaft 4 and the spacing. The distance A is a precise dimension which is important for setting the milling cutter for the milling of the heel of the entire thread profile. The exact distance adjustment A is achieved by the shims 7, which also define the axial play of the shaft 4.

The shaft 4 has a hexagon for the transmission of torque through the clamping ring 10 at the upper end. The drive of the milling fixture is secured by an air drill 11. The feed into the engagement is secured by the driver 9.

The milling tool cleaning procedure is as follows:

The cylinder 2 is in an out-of-work position with the milling cutters B inserted, i.e. the milling cutters 6 inserted inside the circumference of the thread core, so that the milling jig can be screwed into the thread of the workpiece 12. This position is secured by the locking pin 8. The jig is screwed into the thread of the workpiece 12, the roller 2 with the milling cutter 6 is unlocked by the extension of the locking pin 8 and the cylinder 2 is turned into the working position.

The working position is fixed by the locking pin 8 inserted into the locking hole again. The drill 9 is fitted with an air drill 11 with a clamping ring 10 which provides a torque transfer to the shaft 4 of the jig.

Upon further screwing of the jig, the top milling cutter 6 contacts the start of the thread. In this position, the air drill 11 is lowered and, by slowly turning it to the right, the prescribed circumference of the first right-hand thread profile is milled. The air drill is turned off, the jig is screwed into the contact position of the bottom milling cutter 6 with the thread end. The air drill 11 starts and slowly rotates to the left to milling the prescribed circumference of the last thread. It is possible to consider symmetrical and counter-directional milling.

Depending on the selected type of milling or their combination, it is necessary to fit the milling cutters 6 onto the shaft 4, respectively. lower the right or left speed of the air drill 11.

The invention can be used to clean the start and end of internal threads and milling of helical grooves in engineering production.

Claims (1)

SUMMARY OF THE INVENTION A milling fixture for deburring the ends and ends of internal threads with two disc mills, characterized in that it comprises a support sleeve (1), with an external thread identical to the thread of the workpiece (12j, in which the rotary cylinder is eccentrically mounted (2) with an eccentrically mounted shaft (4j provided with milling cutters (6), wherein a locking pin (8) is provided between the support sleeve (1) and the rotary cylinder (2j).