Title of Invention

A BORING BAR

Abstract

A boring bar for being mounted on the spindle of a boring Machine, comprising a cartridge mounted on the said bar; A boring insert mounted on the cartridge for carrying out the boring operation, characterized In that the offset between the axis of the spindle and that of the cartridge is minimized, by shifting the cartridge towards the spindle, such that the radius of rotation of the boring insert is also minimized.

Full Text

This invention relates to a boring bar for enlarging the existing drilled or cast hole in an object such as dowel pin holes in components like Crank Cases used in the automobile Industry. Boring helps to achieve the required bore diameter and tolerance in the components. The conventional boring bar consists of a cartridge with a boring insert, the cartridge being mounted on the boring bar by means of a mounting screw. The boring bar itself is mounted on the machine spindle of the boring machine. The spindle rotates at a high speed e.g. at 500 to 10000 rpm. The rotating insert which is mounted on the cartridge enters the drilled or cast hole in the component, generating the required bore size in the component. The drawback with the known boring bar is that bores of less than a specific diameter e.g. 16 mm diameter, cannot be machined, because cartridges available commercially do not lend themselves to achieving this objective. It Is therefore an object of this invention to propose a boring bar which enables les.ser diameter bores to be machined without any major structural changes in the known boring bar and boring machines. It is also another object of this invention to achieve the above mentioned object simply and effectively. The boring bar for being mounted on the spindle of a boring machine, according to this invention, comprises a cartridge mounted on the said bar; a boring insert mounted on the cartridge for carrying out the boring operation, characterized in that the offset between the axis of the spindle and that of the cartridge is minimized, by shifting the cartridge towards the spindle, such that the radius of rotation of the boring insert is also minimized. This Invention will now be described in further detail by referring to the accompanying drawings which illustrate, In Fig. 1 a boring bar with cartridge known to the art In Fig. 2 an embodiment of the boring bar with cartridge according to this invention, by way of example and not by way of limitation. The conventional boring bar (Fig.l) consists of a cartridge C with a boring insert 3, the cartridge being mounted on the boring bar B by means of a mounting screw M. The boring bar itself is mounted on the machine spindle S of the boring machine. The spindle rotates at a high speed e.g. at 500 to 10000 rpm. The rotating insert J which is mounted on the cartridge enters the drilled or cast hole in the component H, generating the required bore size in the component. A fine adjustment screw F is provided for varying the diameter of boring. The boring diameter is indicated by D. Fig. 2 illustrates an embodiment of this invention. The proposed boring bar Bl (Fig.2) consists of a cartridge CI with a boring insert Jl, the cartridge being mounted on the boring bar Bl by means of a mounting screw Ml. The boring bar itself is mounted on the machine spindle SI of the boring machine. The spindle rotates at a high speed e.g. at 500 to 10000 rpm. The rotating insert Jl which is mounted on the cartridge CI enters the drilled or cast hole in the component HI, generating the required boring size in the component. A fine adjustment screw Fl is provided for v&rying the diameter of boring. The boring diameter is indicated by Dl which is less than the boring diameter D referred to above. Referring to Fig. 1 it will be seen that, in the case of the conventional boring bar B, there is an offset Q between the axis AS of the spindle and the axis AC of the cartridge C. Referring to Fig.2 it will be further seen that, in the case of the proposed boring bar, the offset Ql between the axis ASl of the spindle and the axis ACl of the cartridge CI is reduced to a minimum, by shifting the cartridge CI towards the spindle SI, such that the radius of the rotation of the boring insert Jl is also rendered a minimum, thereby enabling smaller bores (than possible with the conventional boring bar) e.g. 8.5 mm to 16 mm to be machined. The terms and expressions in this specification are of description and not of limitation, as these do not exclude any equivalents of the features Illustrated and described, but various other embodiments of the boring bar proposed herein are possible without departing from the scope and ambit of this invention. We claim : 1. A boring bar for being mounted on the spindle of a boring Machine, comprising a cartridge mounted on the said bar; A boring insert mounted on the cartridge for carrying out the boring operation, characterized in that the offset between the axis of the spindle and that of the cartridge is minimized, by shifting the cartridge towards the spindle such that the radius of rotation of the boring insert is also minimized. A boring bar as claimed in Claim 1 wherein the cartridge is mounted on the spindle by means such as a screw. A boring bar as claimed in Claim 1 or CIaim 2 wherein a fine adjustment screw is provided for varying the diameter of boring. 4. A boring bar substantially as herein described with reference to and as illustrated in the accompanying drawings.

Documents:

0326-che-2003 abstract-duplicate.pdf

0326-che-2003 abstract.pdf

0326-che-2003 claims-duplicate.pdf

0326-che-2003 claims.pdf

0326-che-2003 correspondence-others.pdf

0326-che-2003 correspondence-po.pdf

0326-che-2003 description (complete)-duplicate.pdf

0326-che-2003 description (complete).pdf

0326-che-2003 drawings.pdf

0326-che-2003 form-1.pdf

0326-che-2003 form-26.pdf