RU2448814C1 - Tool overload protection device - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machine tools, particularly, to device preventing microdrill failures in drilling multilayer materials. Proposed device jaw chuck spring loaded axially relative to device case by helical springs arranged in symmetry about case periphery and cylindrical rollers arranged in jaw chuck to allow adjusting radial position in chuck for use of different-diameter tool.

EFFECT: simplified design, expanded applications and higher accuracy.

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Description

The invention relates to metal cutting machines, in particular, can be used for drilling holes of small diameter in multilayer materials without tool breakage.

A device for preventing a tool from overloading [1] is known, which comprises a housing, a clamping device for the tool located in the housing, a tool drive and a sensor associated with an automatic tool feed control system. The device allows you to change the feed rate of the cutting tool in the presence of overloads on torque.

However, the device has several disadvantages:

- there is no regulation for the departure of the drill;

- a constant number of revolutions of the drill;

- insufficiently high accuracy associated with the beating of the instrument;

- reduced reliability of the sensor due to the springs built into the drive.

A device for protecting the tool from overloads is also known, in the housing of which there is a spindle and a tool clamping mechanism and a rack gear located coaxially to the latter, connected to a sensor for monitoring tool overloads by axial force and torque, and containing a cutting mode control system [2].

This device also has low accuracy associated with large beats of the spindle and tool.

The closest in technical essence and the achieved result to the claimed invention is a device [3] (prototype), comprising a housing in which a spindle and coaxial to the last clamping tool, and a rack gear connected by a control sensor to the axle overload control system force and torque, and the sensor is placed in the clamping mechanism with the possibility of interaction with the end face of the tool shank, and the working part of the tool is supported cylindrically and rollers. This device allows to increase the accuracy of processing.

The disadvantage of this device is the design complexity and low level of versatility - the device is designed for one specific diameter of the tool.

The technical result of the invention consists in simplifying the design, expanding the scope of the device and improving the accuracy of processing. The specified technical result is achieved in that the cylindrical rollers covering the working part of the tool are placed in a cam cartridge inserted into the device, spring-loaded in the axial direction relative to the device case, arranged by cylindrical springs symmetrically on the periphery of the body, and the rollers in the cartridge have the ability to be adjusted when changing their radial position for use tool of various diameters.

The invention is illustrated in the drawing, which shows a device for preventing the tool from overloading, General view (section).

The device consists of the following parts: the housing 1, the housing 2 spring-loaded relative to it, the restriction bolt 3 placed symmetrically around the circumference relative to the housing 1 of the springs 4, the locking nut 5, the cam cartridge 6 screwed onto the housing 2. Cylindrical rollers 7 are mounted in the cams of the cartridge 6 , covering and centering the tool 8. Installed coaxially with the spindle 13, the clamping mechanism of the tool 9 is connected via a pusher 10 to the sensor 11 to control the overload of the tool by axial force and torque.

The sensor 11 through the channel 12 in the spindle 13 is electrically connected to the control system of the cutting conditions (not shown).

The device operates as follows. The tool 8 is installed and secured by the clamping mechanism 9. The rollers 7 are pulled by a cam cartridge 6, providing support for the working part of the required diameter of the installed tool 8 and playing the role of a conductor sleeve. When the feed is turned on, the cam chuck 6 abuts against the material being processed and causes the housing 2 to move relative to the housing 1, freeing the cutting part of the tool 8 to perform a drilling operation. In this case, the axial force (torque) is transmitted from the tool 8 to the clamping mechanism 9 and through the pusher 10 to the sensor 11, which sends a signal to the cutting control system via wires in the channel 12, and the latter selects the optimal speed of the spindle 13 and the tool feed 8.

Thus, as a result of using the present invention, the range of used diameters of the end tool is expanded, it is possible to center it during the operation of the device while optimizing cutting conditions.

List of sources

1. Copyright certificate No. 1202744, cl. B23B 47/24, 1984.

2. Copyright certificate No. 1269973, cl. B23B 47/24, 1985.

3. Copyright certificate No. 1745429, cl. B23B 47/24, 1992.

Claims (1)

A device for preventing overloading the tool, comprising a housing in which the drive spindle is placed, a tool clamping mechanism coaxially with it, cylindrical rollers covering the working part of the tool, and also a sensor of the system for automatically controlling the feed of the tool according to axial force and torque, placed in the clamping mechanism with the possibility of interaction with the end face of the tool shank, characterized in that it is equipped with a cam cartridge, axially spring loaded relative to the housing stroystva arranged symmetrically around the periphery of the housing coil springs, and covering the working part of the tool cylindrical rollers housed in the cam holder and adapted to configure its radial position in the cartridge for use tools of different diameters.