GB2162773A

GB2162773A - Boring head, e.g. for forming non-circular holes

Info

Publication number: GB2162773A
Application number: GB08419869A
Authority: GB
Inventors: Georgy Alexandrovi Vasilchenko
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-08-03
Filing date: 1984-08-03
Publication date: 1986-02-12
Also published as: GB8419869D0; GB2162773B

Abstract

A boring head comprises a housing (1) which accommodates a transversely movable carriage (7) carrying a mandrel for a cutting tool (7b) and having a slanted surface engaging a slanted surface of a rod (10) kinematically coupled to a drive which moves the rod in the axial direction. Two other slanted surfaces (17), symmetrical with respect to the axis (a) of rotation of the boring head are engaged by rollers (16) arranged on the ends of a fork (12) spring biassed towards the carriage (7). The boring head further incorporates rocker (18) whose axle (19) is installed in the housing (1) on the side facing the two slanted surfaces (17) of the carriage (7) and is parallel with the axis (a) of rotation of the boring head. Auxiliary rollers (20) mounted on the ends of the fork (12) engage rocker (18). Stops (22) are provided on the external lateral sides of the fork (12) and engage the sides of housing (1) so as to centre the fork (12) about axis (a). <IMAGE>

Description

SPECIFICATION Boring head The present invention realtes to machine tool manufacture and is more specifically concerned with boring heads of multiple-operation machine tools.

The invention is best applicable to multiple-operation machine tools with an automatic change of tools, which are used to machine holes of complicated cross-sectional shapes.

The invention provides a boring head of a multiple-operation machine tool, comprising a housing which is kinematically coupled to a spindle and accommodates a carriage carrying a mandrel for a cutting tool and having a-slanted surface to interact with a slanted surface of a rod arranged in the housing coaxially with the latter and kinematically coupled to a drive which moves the rod in the axial direction, and two more slanted surfaces arranged symmetrically with respect to the axis of rotation of the boring head and interacting with rollers on lines found in a plane extending through the axis of rotation of the boring head, the axles of the rollers being mounted on the ends of a fork so that they extend at a perpendicular to the axis of rotation of the boring head, the fork being arranged in the housing coaxially with the latter and elastically pressed against the carriage, the boring head being characterized, according to the invention, in that it incorporates a rocker whose axle isinstalled-in the housing on the side facing the two slanted surfaces of the carriage and is parallel with the axis of rotation of the boring head, and in that auxiliary rollers are mounted on the ends of the fork for interaction with the rocker, the axles of the auxiliary rollers being parallel with those of the main rollers and arranged in a plane extending through the line of contact between the rollers and the slanted surfaces, the external lateral side of the fork having projections arranged in a plane extending through the axis of rotation of the boring head, which projections are parallel with the axles of the rollers and in contact with the housing.

The fork interacts with the housing in a manner which prevents bending and jamming of the fork in the housing due to friction between the bearing surfaces of the fork end and the housing. The rocker ensures a proper positioning of the fork with respect to the two slanted surfaces of the carriage. The projections on the fork provide for a symmetrical alignment of the fork in relation to the housing.

Being relatively simple in construction, the boring head according to the invention provides for playfree motion of the carriage in the housing of the boring head, which considerably improves the accuracy of machining and raises the efficiency of the boring machine. The boring head of this invention is reliable in operation and has a long service life.

A better understanding of the present invention will be had from a #consideration of the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, wherein: Figure 1 is an elevation view of a boring head in accordance with the invention; Figure 2 is a section taken on line Il-Il in Figure l; Figure 3 is a section taken on line Ill-Ill in Figure 2; Figure 4 is a section taken on line IV-IV in Figure 3.

Referring to the attached drawings, the boring head according to the invention comprises a housing 1 (Figure 1.) composed of a cheek 2, a block 3, and a mandrel 4 kinematically coupled to a spindle 5 which rotates the boring head. The housing 1 accommodates rolling contact bearings 6 in which there is mounted a carriage 7 carrying a mandrel 7a with a cutting tool 7b.

The carriage 7 accommodates a cylindrical finger 8 with a flat 9 which is its slanted surface. A rod 10 is arranged in the housing 1 coaxially with the latter. The rod 10 is-kinematically coupled to a drive (not shown) which drives the rod 10 in the axial direction. The rod 10 has a slanted surface 11 to interact with the flat 9 of the finger 8 of the carriage 7 and move the carriage 7 in the radial direction.

Arranged in the housing 1 coaxially with the latter is a fork 12 which is interposed between the housing 1 and the rod 10. The fork 12 is made hollow and is pressed against the housing 1 and the carriage 7 by a spring 13. One end of the spring 13 bears up against the housing 1. Its opposite end bears up against a shoulder 14 provided on the fork 12. Axles 15 of rollers 16 are mounted on the ends of the fork 12 symmetrically with respect to the axis "a" of rotation of the boring head. The axles 15 extend at a perpendicular to the axis "a" of rotation of the boring head (Figures 2 and 3) and interact with slanted surfaces 17 (Figures 3 and 4) of the carriage 7. The slanted surfaces 17 (Figure 4) are arranged symmetrically in relation to the axis "a" of rotation of the boring head.The rollers 16 interact with the slanted surfaces 17 on lines found in a plane extending through the axis "a" of rotation of the boring head.

The housing 1 accommodates a rocker 18 whose axle 19 (Figure 2) is secured in the mandrel 4 and is parallel with the axis "a" of rotation of the boring head, facing the slanted surfaces 17 (Figure 4) of the carriage 7. The arms of the rocker 18 interact with auxiliary rollers 20 mounted on the ends of the fork 12. Axles 21 of the auxiliary rollers 20 are parallel with the axles 15 of the rollers 16 and arranged in a vertical plane extending through the line of contact between the rollers 16 and the slanted surface 17 of the carriage 7. Stops 22 are provided on the external surface of the fork 12.

These serve to align the fork 12 symmetrically with respect to the carriage 7 and are arranged in a plane extending through the axis "a" of rotation of the boring head. The stops 22 are parallel with the axles 15 of the rollers 16 and in contact with the housing 1. The part of the housing where the carriage 7 is located is contained in- an enclosure 23 (Figure 1). On the side of the cheek 2 there is a guard 24 mounted on the carriage 7.

The boring head according to the invention operates as follows.

The tools 7b are fixed in the mandrel 7a of the boring head which is rotated by the spindle 5. The rod 10 is in its extreme left position (according to the drawing). As the head rotates, the rod 10 moves to the right The spring 13 drives the fork 12 to the left until the auxiliary rollers 20 abut against the rocker 18. The rollers 16 abut against the slanted surfaces 17 of the carriage 7, driving the carriage 7 and the mandrel 7a with the tool 7b towards the axis "a" of rotation of the boring head.

The force of the spring 13 is transmitted to-the slanted surfaces 17, preventing play between the carriage 7, cylindrical finger 8, rod 10 and -block 3, and between the carriage 7, rolling contact bearings 6 and cheek 2. This guarantees a high accuracy of machining. Depending on the position of the rollers 16, the auxiliary rollers 20 act on the arms of the rocker 18. The rocker 18 swivels about its axle 19, eliminating play between the auxiliary rollers- 20, rocker 18 and axle 19 secured in the housing. 1. The stops 22 of the fork 12 limit the range of movement of the fork 12 in the direction perpendicular to that of the motion of the carriage 7 and to the axis "a" of rotation of the boring head. Thus the fork 12 is maintained in a position symmetrical with respect to the carriage 7.

As the rod 10 moves to the left, the slanted surfaces 17 of the carriage 7 act on the rollers 16 and move the fork 12 to the right, overcoming the resistance of the spring 13. The auxiliary rollers 20, rocker 18 and-stops 22 function as described above.

The rocker 18 and the auxiliary rollers 20 which interact with the former provide for a proper positioning of the fork 12 and a good, jamming-free, contact between the rollers 16 and the slanted surfaces 17 of-the carriage 7. The stops 22 on the fork 12 ensure a proper centering of the fork 12 in the housing 1.

The mutual positioning of the rocker 18, auxiliary rollers 20 and stops 22 reduces deformations of the fork 12. Reducing deformations of the rod 10, fork 12 and carriage 7 and preventing their jamming are factors which improve the response and raise the efficiency of the boring machine. According to preliminary estimates, the boring head in accordance with the invention raises the efficiency of boring machines by 15 to 20 per cent and guarantees the second class of accuracy. The boring head of this invention is simple in design and cheap.

Prototype boring- heads according to the invention are cheaper by 10 to 15 per cent than conventional boring heads.

Claims

1. A boring head of a multiple-operation machine tool, comprising a housing kinematically coupled to a spindle and accommodating a carriage carrying a mandrel for a cutting tool and having a slanted surface to interact with a slanted surface of a rod arranged in the housing coaxially with the latter and kinematically coupled to a drive which moves the rod in the axial direction, and two more slanted surfaces arranged symmetrically with respect to the axis of rotation of the boring head and interacting on lines found in a plane extending through the axis of rotation of the boring head with rollers whose axles are perpendicular to the axis of rotation of the boring head, being mounted on the ends of a fork elastically pressed against the carriage, the fork being arranged in the housing coaxially with the latter; the boring head further incorporating a rocker whose axle is secured in the housing on the side facing the two slanted surfaces of the carriage parallel with the axis of rotation of the boring head, the ends of the fork carrying auxiliary rollers interacting with the rocker, their axles being parallel with those of the main rollers and in a plane extending through the line of contact between the rollers and the slanted surfaces, with stops being provided on the external lateral sides of the fork and arranged in a plane extending through the axis of rotation of the boring head, said stops# being parallel with the axles of the rollers and in contact with the housing.

2. A boring head of a multiple-operation machine tool, substantially as hereinbefore described with reference to the accompanying drawings.