System of variable hydrostatic guideway for vertical lathes and a vertical lathe that includes said guideway

Abstract

A variable hydrostatic track system for vertical lathes includes a plurality of sectors arranged between the periphery and the central opening of an annular base. Each sector includes an upper housing with a hydraulic fluid outlet such that when the injected hydraulic fluid overflows from the housings, it forms a film between the rotating chuck and the sectors. The track system further includes a positioning mechanism having a plurality of hydraulic cylinders fixed on the annular base in a radial direction between the central opening and the sectors. The rod of each hydraulic cylinder is coupled to a piston and to one of the sectors. Each sector is guided in a radial guidance element such that, due to the action of the hydraulic cylinder, the sector is movable between an inner radial position and an outer radial position.

Claims

1. Variable hydrostatic track system for vertical lathes which comprises an annular base arranged between a support base and a securing rotating chuck of a vertical lathe, a central opening in the annular base which surrounds a rotation shaft of the rotating chuck; a plurality of sectors forming a circle and projecting vertically between a periphery of the annular base and the central opening of the annular base, each sector comprising an upwardly open upper housing; at least one hydraulic fluid outlet arranged at the bottom of each housing and which allows injecting hydraulic fluid into the corresponding housing such that, when the injected hydraulic fluid overflows from the housings, the hydraulic fluid pushes the rotating chuck upwards, forming a film of hydraulic fluid between the rotating chuck and the sectors; and further comprising a positioning mechanism capable of positioning the sectors at least in an inner radial position in which at least one part of the sectors is arranged at a circumference of a minimum diameter and in an outer radial position in which at least one part of the sectors is arranged at a circumference of a maximum diameter.

2. System according to claim 1, wherein the positioning mechanism is designed to position at least one part of the sectors at least in an intermediate position between said inner radial position and said outer radial position.

3. System according to claim 1, wherein the positioning mechanism is designed to individually position each sector in one of said positions.

4. System according to claim 1 wherein the positioning mechanism comprises a plurality of double-acting hydraulic cylinders fixed on the annular base in a radial direction between the central opening and the sectors, each hydraulic cylinder comprising a barrel cylinder, a bottom chamber, a head chamber, and a rod coupled at an end to a piston moving linearly in the barrel cylinder, and at another end to one of the sectors; each sector coupled to a hydraulic cylinder is guided at least in a radial guidance element such that, due to the action of the hydraulic cylinder, the sector is movable between the inner radial position in which the hydraulic cylinder is locked in its retracted position and the outer radial position in which the hydraulic cylinder is locked in its extended position.

5. System according to claim 4, wherein it comprises at least one pair of hydraulic cylinders fixed respectively in radially opposite directions in a diagonal line of the annular base which are coupled to both respective diagonally opposite sectors.

6. System according to claim 4, wherein each of the radial guidance elements is made up of a wedge-shaped block respectively projecting from the annular base between two adjacent sectors.

7. System according to claim 4, wherein the rod of each hydraulic cylinder comprises an inner passage with a first end part connected to an intake connection for the hydraulic fluid which is injected into the housing of the sector and a second end part connected to the hydraulic fluid outlet in the housing of the sector to which the hydraulic cylinder is connected.

8. System according to claim 7, wherein a first end of the hydraulic cylinder is fixed in the annular base by means of a first anchor body anchored to the annular base in the proximity of the central opening and a second end of the hydraulic cylinder, through which the rod projects, is fixed in the annular base by means of a second anchor body; the intake connection for hydraulic fluid which is injected into the housing of the sector is comprised in the first anchor body; in the inner passage of the rod of the hydraulic cylinder there is housed an inner tube which traverses the piston and is fixedly connected at one of its ends to the intake connection for the hydraulic fluid such that, when the rod is extended and retracted, the wall of the inner passage of the rod and the piston slide on said inner tube; the inner tube has a length such that the hydraulic fluid flows into said inner passage both when the rod is in a maximum extension position and when the rod is in a maximum retraction position.

9. System according to claim 8, wherein the first anchor body comprises a first conduit connecting the bottom chamber of the hydraulic cylinder with a first connection to a hydraulic circuit feeding the hydraulic cylinder and the second anchor body comprises a second conduit connecting the head chamber of the hydraulic cylinder with a second connection of the hydraulic circuit.

10. System according to claim 8, wherein the hydraulic cylinder comprises a bottom integrated in the first anchor body and a head integrated in the second anchor body.

11. System according to claim 8, wherein the first anchor body comprises a through hole for housing a first pressure sensor for measuring the pressure of the hydraulic fluid in the bottom chamber.

12. System according to claim 8, wherein the second anchor body comprises a through hole for housing a pressure sensor for measuring the pressure of oil in the head chamber.

13. System according to claim 8, wherein the first anchor body and the second anchor body are attached to each other by means of four connection bars coaxially surrounding the barrel cylinder; and/or wherein the first anchor body and the second anchor body each comprise two side flanges screwed to the annular base.

14. System according to claim 1, wherein each of the hydraulic cylinders can be driven independently of the others; and/or wherein each hydraulic cylinder can be locked at least in an intermediate position between said retracted position and said extended position; and/or wherein the system comprises a variable preloading device comprising a central hydraulic cylinder.

15. Vertical lathe comprising a support base, a securing rotating chuck and a hydrostatic track on which the rotating chuck rotates, wherein it comprises a variable hydrostatic track system such as the one defined in one of the previous claims.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Aspects and embodiments of the invention are described below on the basis of schematic drawings, in which

(2) FIG. 1 is a top perspective view of the base of a vertical lathe incorporating an embodiment of the system according to the present invention, in a first maximum extension position of the variable hydrostatic track;

(3) FIG. 2 is a top perspective view, corresponding to FIG. 1, in which the hydrostatic track is in a medium extension position;

(4) FIG. 3 is a top perspective view, also corresponding to FIG. 1, in which the hydrostatic track is in a minimum extension position;

(5) FIG. 4 is a top plan view of the base and track shown in FIG. 1;

(6) FIG. 5 is a top plan view of the base and track shown in FIG. 2;

(7) FIG. 6 is a top plan view of the base and track shown in FIG. 3;

(8) FIG. 7 is a top plan view of the base and track shown in FIGS. 1 to 7, in a position in which the hydrostatic track is formed such that the adjacent sectors are in alternating positions such that some form a circumference of a minimum diameter and others form a circumference of an intermediate diameter.

(9) FIG. 8 is a section view of a chuck which can be coupled to the base shown in FIG. 1.

(10) FIG. 9 is a section view through the line A-A shown in FIG. 4;

(11) FIG. 10 is a section view of the chuck of FIG. 8 assembled in the base with the hydrostatic track of FIG. 9, in a resting position of the vertical lathe;

(12) FIG. 11 is a section view of the chuck of FIG. 8 assembled in the base with the hydrostatic track of FIG. 9, in a rotation position of the vertical lathe;

(13) FIG. 12 is a perspective view of an embodiment of an actuating cylinder or the hydrostatic track of the present invention;

(14) FIG. 13 is a side view of the actuating cylinder shown in FIG. 11;

(15) FIG. 14 is an upper longitudinal section view of the actuating cylinder shown in FIG. 11;

(16) FIG. 15 is a rear view of the actuating cylinder shown in FIG. 11;

(17) FIG. 16 is a front view of the actuating cylinder shown in FIG. 11;

(18) FIG. 17 is a partially sectioned side view of an embodiment of a hydraulic preloading system applicable to vertical lathes with hydrostatic tracks and can be incorporated in the embodiments of the invention shown in the previous figures.

(19) In these figures there are reference numbers which identify the following elements: 1 annular base 1a central opening of the annular base 1b periphery of the annular base 2 support base 3 securing rotating chuck 3a rotation shaft of the rotating chuck 4 sector 4a upper housing 4b hydraulic fluid outlet 5 hydraulic cylinder 5a barrel cylinder 5b bottom chamber 5c head chamber 5d rod 5e inner passage 5f first end part of the inner passage 5g second end part 5h bottom of the hydraulic cylinder 5i head of the hydraulic cylinder 5j piston of the hydraulic cylinder 6 radial guidance element 7 intake connection for the hydraulic fluid 8 first anchor body 8a first conduit 8b through hole 8c, 8d side flange 9 second anchor body 9a second conduit 9b through hole 9c, 9d side flange 10 inner tube 10a ends of the inner tube 11a pressure sensor 11b pressure sensor 12 connection bar

EMBODIMENTS OF THE INVENTION

(20) FIGS. 1 to 11 show an embodiment in which the hydrostatic track system comprises an annular base -1- arranged between a support base -2- and a securing rotating chuck -3- of a vertical lathe. The annular base -1- has a central opening -1a- which surrounds a rotation shaft -3a- for the rotating chuck -3-. Between the periphery -1b- and the central opening -1a- of the upper surface of the annular base -1- there are arranged twelve sectors -4- in the form of arched bodies made of bronze, coupled to the rods -5d- of respective double-acting hydraulic cylinders -5- fixed on the annular base in a radial direction between the central opening -1a- and the sectors -4-. Each hydraulic cylinder can be driven independently from the others, and respectively two of the hydraulic cylinders -5- are arranged diametrically opposite along respective diametric lines of the annular base -1-, such that six pairs of hydraulic cylinders are formed in which such hydraulic cylinders are in diametrically opposite positions. The sectors -4- are guided in radial guidance elements made as wedge-shaped blocks -6- respectively projecting from the annular base -1- between two adjacent sectors -4-. The blocks -6- are shorter than the sectors -4-. Each sector -4- has an upwardly open upper housing -4a- and a hydraulic fluid outlet arranged at the bottom of the housing -4a- which allows injecting hydraulic fluid -4a- such that, when the injected hydraulic fluid overflows from the housings -4a-, the hydraulic fluid pushes the rotating chuck 3- upwards (see FIG. 11), forming a film of hydraulic fluid between the rotating chuck and the sectors -4-.

(21) The sectors -4- are guided by the guidance blocks -6- such that, due to the action of the respective hydraulic cylinders, each sector is movable between an outer radial position in which the rod -5a- of the corresponding hydraulic cylinder -5- is locked in its extended position (see FIGS. 1, 4 and 7), an intermediate position in which the rod -5a- of the corresponding hydraulic cylinder -5- is locked in an intermediate extension position (see FIGS. 2, 5 and 7) and an inner radial position in which the rod -5d- of the corresponding hydraulic cylinder -5- is locked in its retracted position (see FIGS. 3, 6 and 7).

(22) It is thus possible to position the sectors -4- so that they form respective circumferences with a maximum diameter (see FIGS. 1 and 4), a minimum diameter (see FIGS. 2 and 5), an intermediate diameter (see FIGS. 3 and 6), or circumferences in which the adjacent sectors -4- are in alternating positions such that some form a circumference of a minimum diameter and others form a circumference of an intermediate diameter (see FIG. 7) or other combinations (not illustrated in the figures).

(23) FIGS. 8 to 16 show an embodiment of a hydraulic cylinder -5- which can integrated in the system according to the present invention. The hydraulic cylinder -5- conventionally comprises a barrel cylinder -5a-, a bottom chamber -5b-, a head chamber -5c- and a rod -5d- coupled at one of its ends to a piston -5j- moving linearly inside the barrel cylinder -5a-, and at the other end to one of the sectors -4-.

(24) The hydraulic cylinder -5- is fixed to the annular base -1- at one of its ends by means of a first anchor body -8- anchored to the annular base -1- in the proximity of the central opening -1a-, and at its opposite end, through which the rod -5d- projects, by means of a second anchor body -9-. The intake connection -7- for the hydraulic fluid which is injected into the housing -4a- of the sector -4- is comprised in the first anchor body -6-. In an inner passage -5e- of the rod -5d- there is housed an inner tube -10- which traverses the piston -5j- and is fixedly connected at one of its ends to the intake connection -7- for the hydraulic fluid such that when the rod -5d- is extended and retracted, the wall of the inner passage -5e- of the rod -5d- slides in the periphery of the inner tube -10-. The inner tube -10- has a length such that the hydraulic fluid flows into the inner passage -5e- both when the rod -5d- is in its maximum extension position and when the rod -5d- is in its maximum retraction position. The anchor bodies -8, 9- are respectively provided with two side flanges -8c, 8d, 9c, 9d- capable of being screwed to the annular base -1- and attached to one another by means of four connection bars -12- coaxially surrounding the barrel cylinder -5a-.

(25) The first anchor body -8- further comprises a first conduit -8a- connecting the bottom chamber -5b- of the hydraulic cylinder -5- with a first connection to a hydraulic feed circuit (not shown in the figures) whereas the second anchor body -9- comprises a second conduit -9a- connecting the head chamber -5c- of the hydraulic cylinder -5- with a second connection of this hydraulic circuit. The bottom -5h- of the hydraulic cylinder -5- is integrated in the first anchor body -8- and the head -5i- thereof in the second anchor body -9-. The first anchor body -8- further comprises a through hole -8b- in which there is housed a first pressure sensor -11a- measuring the pressure of the hydraulic fluid in the bottom chamber -5b- of the hydraulic cylinder -5-, and the second anchor body -8- in turn comprises a through hole -9b- for housing a pressure sensor -11b- measuring the pressure of oil in the head chamber -5c-.

(26) FIG. 17 shows an embodiment of a variable preloading device of the hydrostatic track which comprises a central hydraulic cylinder by means of which the hydrostatic fluid can be preloaded according to the chosen configuration of the track, i.e., the position of the respective sectors.