US3750496A

US3750496A - Device for spherical turning

Info

Publication number: US3750496A
Application number: US00229005A
Authority: US
Inventors: A Ivanov; R Romanov
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-02-24
Filing date: 1972-02-24
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07

Abstract

The device comprises a faceplate with a drive providing for rotation of the faceplate. In addition, the device comprises a support and a support feed mechanism. The support is made in the form of a lever of the secondclass at one end of which there is arranged a bearing made as a ball-and-socket joint and associated with the faceplate at a point located on the axis of rotation of the faceplate and on the other end of which there is located a tool holder mounting the rotary cup tool. The tool holder is equipped with means for controlling the degree of rotation of the cup holder in the process of turning the spherical surface. The spherical surface being turned, the faceplate and the support form a single closed dynamical system.

Description

United States Patent [1 1 Ivanov et al.

[4 1 Aug. 7, 1973 DEVICE FOR SPHERICAL TURNING [76] Inventors: Alexandr Pavlovich Ivanov, Nevsky prospekt, 139, kv. 76; Rudoll Alexeevlch Romanov, ulitsa Kuibysheva, 21, kv. 54, both of Leningrad, U.S.S.R.

[22] Filed: Feb. 24, 1972 [21] Appl. No.: 229,005

[52] U.S. Cl. 82/12, 82/1.5 [51] Int. Cl B23b 5/40 [58] Field of Search 82/12, 11, 1.5

[56] References Cited UNITED STATES PATENTS 3,186,268 6/1965 Hoglund 82/11 537,]26 4/1895 Schuckert et al 82/11 X FOREIGN PATENTS OR APPLICATIONS 939,548 2/1956 Germany 82/12 37,930 10/1906 Switzerland 82/12 Primary Examiner-Le0nidus Vluchos AttorneyEric H. Waters et al.

[57] ABSTRACT The device comprises a faceplate with a drive providing for rotation of the faceplate.

In addition, the device comprises a support and a support feed mechanism. The support is made in the form of a lever of the secondclass at one end of which there is arranged a bearing made as a ball-and-socket' joint and associated with the faceplate at a point located on the axis of rotation of the faceplate and on the other end of which there is located a tool holder mounting the rotary cup tool.

The tool holder is equipped with means for controlling the degree of rotation of the cup holder-in the process of turning the spherical surface. The spherical surface being turned, the faceplate and the support form a single closed dynamical system.

5 Clalms, 4 Drawing Flgures PAIENILL Aw: H913 SHEET 1 [1F 2 DEVICE FOR SPHERICAL TURNING The present invention relates to mechanical engineering and, more particularly, the invention relates to devices for turning spherical surfaces.

Known in the art is a device for turning spherical surfaces in which a pedestal mounted in the centre of the faceplate of a vertical lathe carries a support in the form of a lever of the second class the free end of which is provided with a holder for a rotary cup tool. The support is equipped with a feed mechanism (c.f. Technical Sheet No. 6, series 2, 1966 the central technical information bureau of the Leningrad National Economy Council, USSR).

The known device does not provide for accurategeometry spherical surface (with a deviation from a correct geometrical form of not higher than 0.01 mm) necessary in various scientific and technical instruments and apparatus, for example in the bearings of the horizontal axle of a great azimuthal telescope having a diameter of 2,200 mm or in large-size rolling-friction bearings.

This stems from the fact that the known device has a disadvantage from the viewpoint of inevitable manufacturing errors determined by the system of tolerances and fits.

What is more, elimination of the axial play in the pedestal of the device is effected downwardly during the movement of the support from its upper position to the horizontal position while elimination of this play during the movement of the support from the horizontal to the bottom position is effected upwardly.

Consequently, the centre of rotation of the support is not accurately fixed but floats within the space of the permissible play.

An object of the present invention is to eliminate the above-mentioned disadvantages.

The specific object of the invention is to provide a simple device for turning spherical surfaces in which the errors of all its links are practically compensated and allow this device to be used for precision turning of spherical surfaces with a deviation from the corrct geometrical form of not higher than 0.01 mm.

These and other objects are attained by providing a device for spherical turning comprising a faceplate with a drive for its rotation, a support made as a lever of the second class and having at one its end a bearing coupled to the faceplate at a point lying on the axis of rotation of the faceplate and having at its other end a tool holder for mounting a rotary cup tool, and a support feed mechanism; according to the invention, this bearing is made in the form of a ball-and-socket joint and the tool holder is equipped with means for controlling the degree of rotation of the tool in the process of turning the spherical surface, in which case the spherical surface faceplate and support form a single closed dynamical system.

The ball-and-socket joint is preferably composed of a ball rigidly connected to the faceplate and a socket member encompassing the ball and rigidly connected to the support so as to ensure uniform distribution of forces between all the points of contact with the ball.

The socket member of the joint may be made with a possibility of a contact with the ball along a circular surface. The socket member of the ball-and-socket joint is preferably provided with three diamond projections contacting the ball in three points disposed in the apices of an equilateral triangle.

The means for controlling the degree of rotation of the cup tool is preferably made as a drum rigidly secured to the tool, a rope having one end secured on the cylindrical surface of the drum and passed through a guide roller mounted on the support and having the other end fixed in a stationary clamp, in which case the place of mounting of the guide roller is to be determined depending on the conditions of a required angle of rotation of the cup tool during its one pass along the surface being machined.

The proposed device provides for precision turning of spherical surfaces with a high degree of accuracy of the geometrical form.

This device was employed for turning a radial block bearing with a diameter of its internal sphere of 2,200 mm for a large telescope. In this case the deviation of the surface from a correct geometrical form was not in excess of 0.01 mm despite the fact that the radial and axial play of the faceplate was within 0.2-0.3 mm.

The proposed device may be built around a typical metal cutting machine, for example a vertical lathe. In this case the faceplate of the vertical lathe serves as a faceplate of the proposed device.

The invention will be-better understood from the following detailed description of some particular embodiments thereof, reference being made to the accompanying drawings, in which:

FIG. 1 shows a device for turning internal spherical surfaces according to the invention;

FIG. 2 is a sectional view of the support taken in the line II-lI of FIG. 1;

FIG. 3 is a view taken along the arrow A in FIG. 1;

FIG. 4 is a device for turning external spherical surfaces according to the invention.

The device 1 for turning internal spherical surfaces has a faceplate 2 (FIGS. 1, 2, 3) with a drive 3 for rotating the faceplate 2. The drive of the faceplate 2 may be accomplished as any known mechanism of this type used in metal cutting machines providing for rotation of the faceplate with a required speed necessary for predetermined turning conditions.

Installed on the faceplate coaxially therewith is a pedestal 4 which is kinematically connected to a support 6 through a ball-and-socket joint 5.

The ball-and-socket joint 5 consists of a ball 7 with a tail (not shown) pressed into the pedestal 4 and a socket member 8 rigidly secured to the support 6. The ball 7 is made with a high accuracy and has a tolerance from an accurate geometrical form of not higher than 3 microns.

The socket member 8 consists of a split spherical bearing with a babbit lining scraped to the ball 7.

However, the socket member 8 of the ball-andsocket joint 5 may be made with three diamond projections which contact the ball 7 in three points disposed in apices of an equilateral triangle.

The support 6 mounted through its one end on the pedestal 4 by means of the ball-and-socket joint 7 has a tool holder 9 at its other end and is kinematically connected with a feed mechanism 10. This connection is effected'through bronze blocks II which are fitted on a rod 12 pressed into the support 6 between its ends. The blocks II are placed in the slots 13 of the holder 15 of the support 6. Springs 14 are also placed in the slots 13.

Thus, the support 6 consists of a lever of the second class one arm of which is located between the pedestal 4 and the holder 15 of the support 6 while the other arm of the lever is located between the pedestal 4 and the tool holder 9.

The mechanism 10 for feeding the support 6 includes a drive l6, a link 17 and the holder of the support 6.

The feed drive 16 may be of any known construction among those used for metal cutting machines and providing for feeding the support 6 with a specified speed required for predetermined conditions of the process of turning.

The tool holder 9 has a socket 18 for a cup tool 19 disposed relative to the spherical surface 1 being turned so as to provide its self-rotation during the process of cutting. (The direction of the self-rotation of the tool is shown by an arrow in FIG. 3).

The tool 19 is fitted on one end of the roller 20, a drum 2! being fitted on the other end thereof.

Fixed to the drum 21 is a rope 22 laid along the support 6 to the roller 23 mounted on the same and then passed to a stationary clamp 24.

Such mounting of the tool 19 ensures its limited selfrotation in which the tool makes only one revolution per its pass along the spherical surface being machined. The length of the cutting edge of the tool is selected so that each elementary portion of the cutting edge of the tool corresponds to such an area of the machined surface at which there is no any appreciable wear of this elementary portion of the tool.

The limited self-rotation can be effected by fixing the end of the rope 22 passing from the drum 21 in the point of intersection of arcs having radii L and L +1, where L is the radius of the sphere being machined (or, more particularly, the length of the lever from the point of fixing the tool 19 to the centre of the ball 7); l is the length of the arc of the single-turn drum 21, in which case the are L H is drawn from the point 25 of the beginning of the turning, while the are L is drawn from the end of the turning of the spherical surface.

The process of turning of a spherical surface 1 is effected as follows. Simultaneously with the rotation of the faceplate 2 the support 6 moves upwards under the action of the feed mechanism 10.

The tool 19, while moving from the point 5 to the point 25, performs the turning of the entire spherical surface.

in this case the tool 19 performs a single revolution per cycle of turning the spherical surface 1 due the limited self-rotation of the tool provided by its mounting as described above.

FIG. 4 shown another modification of the proposed device intended for turning external spherical surfaces. In principle it does not differ from the above-described device except for the shape of the support 27 which is made as a L-shaped member.

We claim:

1. A device for turning spherical surfaces comprising in combination: a faceplate, a drive providing for rotation of said faceplate, a support in the form of a lever of the secondclass, a mechanism for feeding said support, abearing made in the form of a ball-and-socket joint disposed at one end of said support and connected to said faceplate at a point located on the axis of rotation of said faceplate, a rotary cup tool, a tool holder for said rotary cup tool disposed at the other end of said support, means for controlling the degree of rotation of said cup tool in the process of turning said spherical surface, said holder mounting said tool, while said spherical surface, faceplate and support forming a single closed dynamical system.

2. A device for turning spherical surfaces as claimed in claim 1, in which said ball-and-socket joint consists of a ball rigidly connected with said faceplate and a socket member encompassing said ball and rigidly connected with said support so as to provide for uniform distribution of forces between all the points of contacts of said socket member with said ball.

3. A device for turning spherical surfaces as claimed in claim 2, in which said socket member of said balland-socket joint contacts said ball along a circular surface.

4. A device for turning spherical surfaces as claimed in claim 2, in which said socket member of the balland-socket joint is equipped with three diamond supporting projections contacting said ball in three points disposed at apices of an equilateral triangle.

5. A device for turning spherical surfaces as claimed in claim 1, in which said means for controlling the degree of rotation of said cuptool comprises a drum rigidly connected to said tool, a rope one end of which is secured on the cylindrical surface of said drum and passed through a guide roller mounted on said support, while the other end of the rope is secured in a stationary clamp, the place of. mounting of said guide roller being determined depending on the condition of provision of a required angle of rotation of said cup tool per its pass along the spherical surface being machined.

I! I8 l i

Claims

1. A device for turning spherical surfaces comprising in combination: a faceplate, a drive providing for rotation of said faceplate, a support in the form of a lever of the secondclass, a mechanism for feeding said support, a bearing made in the form of a ball-and-socket joint disposed at one end of said support and connected to said faceplate at a point located on the axis of rotation of said faceplate, a rotary cup tool, a tool holder for said rotary cup tool disposed at the other end of said support, means for controlling the degree of rotation of said cup tool in the process of turning said spherical surface, said holder mounting said tool, while said spherical surface, faceplate and support forming a single closed dynamical system.

3. A device for turning spherical surfaces as claimed in claim 2, in which said socket member of said ball-and-socket joint contacts said ball along a circular surface.

4. A device for turning spherical surfaces as claimed in claim 2, in which said socket member of the ball-and-socket joint is equipped with three diamond supporting projections contacting said ball in three points disposed at apices of an equilateral triangle.

5. A device for turning spherical surfaces as claimed in claim 1, in which said means for controlling the degree of rotation of said cup tool comprises a drum rigidly connected to said tool, a rope one end of which is secured on the cylindrical surface of said drum and passed through a guide roller mounted on said support, while the other end of the rope is secured in a stationary clamp, the place of mounting of said guide roller being determined depending on the condition of provision of a required angle of rotation of said cup tool per its pass along the spherical surface being machined.