WO2014102689A1

WO2014102689A1 - Vertical lathe with pick-up spindle movable along a circular path

Info

Publication number: WO2014102689A1
Application number: PCT/IB2013/061212
Authority: WO
Inventors: Aldo Servetto
Original assignee: SIECAB Srl
Current assignee: SIECAB Srl
Priority date: 2012-12-27
Filing date: 2013-12-20
Publication date: 2014-07-03
Anticipated expiration: 2015-06-27
Also published as: CN203956637U; ITTO20121148A1; TW201440930A

Abstract

The vertical lathe (10) comprises: a base (12), a drum (14) supported by the base (12) ro- tatably about a vertical axis of rotation (z), at least one workpiece-carrying spindle (16) formed as an inverted vertical spindle, a plurality of tool-carrying devices (24) mounted on the base (12) so as to allow the respective tools to machine a workpiece carried by the workpiece-carrying spindle (16), and at least one machining unit (30) and at least one counter-head (26) which are mounted on the base (12). The workpiece-carrying spindle (16) is mounted on the drum (14) in such a manner that its axis of rotation (z1) is movable together with the drum (14) along a circular path having its centre on the axis of rotation (z) of the drum (14) and in such a manner that said workpiece-carrying spindle (16) is also movable in a vertical direction (z1). Each machining unit (30) comprises a tool-carrying turret or head (32), the axis (y) of which is oriented horizontally and is located at a distance from the axis of rotation (z) of the drum (14) smaller than the distance between the axis of rotation (z) of the drum (14) and the axis of rotation (z1) of the at least one workpiece- carrying spindle (16), and movement means (36, 38, 42, 44) designed to move the tool- carrying turret or head (32) relative to the base (12) and to the drum (14) at least along its axis (y). Each counter-head (26) comprises a clamping device (28) for clamping a work- piece to be machined, the axis (z2) of said clamping device (28) being oriented vertically and being located at a distance from the axis of rotation (z) of the drum (14) substantially equal to the distance between the axis of rotation (z) of the drum (14) and the axis of rotation (z1) of the at least one workpiece-carrying spindle (16), and motor means for rotation- ally driving the clamping device (28) about its axis (z2).

Description

Vertical lathe with pick-up spindle movable along a circular path

The present invention relates generally to a vertical lathe comprising at least one workpiece-carrying spindle formed as an inverted vertical spindle (typically known as a pick-up spindle). More specifically, the present invention relates to a vertical lathe of the type mentioned above, further comprising a base and a drum supported by the base rotatably about a vertical axis of rotation, wherein each workpiece-carrying spindle is mounted on the drum in such a manner that its axis is movable together with the drum along a circular path having its centre on the vertical axis of rotation of the said drum, as specified in the preamble of independent Claim 1.

A vertical lathe of the type mentioned above is known from International Patent Application WO2011/048483 in the name of the Applicant. According to such a known solution, each workpiece-carrying spindle is rotatable about its axis (and therefore about an axis of rotation parallel to the axis of rotation of the drum) and is also mounted on the drum so as to be displaceable in the vertical direction (and therefore along a direction parallel both to its axis of rotation and to the axis of rotation of the drum). Each workpiece-carrying spindle is provided with a respective clamping device for clamping a workpiece to be machined. A plurality of tool-carrying devices are mounted on the base and may be formed ei- ther as rotating tool-carrying turrets, in particular each arranged with its axis of rotation in a horizontal plane (and therefore in a plane perpendicular to the axis of rotation of the drum), or as tool-carrying heads each able to hold a single tool. The tool-carrying devices are placed substantially along a circumference vertically aligned with the circumference along which the axis of each workpiece-carrying spindle moves, i.e. along a circumference having its centre on the axis of rotation of the drum and radius equal to the distance between the axis of rotation of the drum and the axis of each workpiece-carrying spindle. Turning of the workpiece carried by the workpiece-carrying spindle (or by one of the workpiece-carrying spindles) is carried out using the rotary movement of the drum, and therefore of the axis of the spindle, about its vertical axis of rotation and the translatory movement of the spindle in the vertical direction in order to control the feeding and depth of the turning operation. While the workpiece-carrying spindle, and along with it the workpiece being machined, moves vertically downwards or upwards with respect to the tool, it also moves along a circular path having its centre on the axis of rotation of the drum so as to bring the workpiece into contact with the tool and machine it to the desired shape. The rotary movement of the workpiece-carrying spindle about the axis of rotation of the drum replaces therefore the translatory movement along the X axis of the conventional lathes. The tools carried by the tool-carrying devices may be equally well fixed tools or rotary tools, so that the lathe is also able to perform machining operations other than turning.

One of the main advantages of such a type of vertical lathe consists in the greater amount of space available for the tools, compared to conventional vertical lathes, allowing a greater number of tools to be mounted and therefore a greater flexibility, i.e. greater capacity to carry out different operations, to be obtained. A further advantage of such a type of vertical lathe consists in the fewer problems caused by thermal drift, i.e. in the reduced impact of the variations in temperature on the precision of the machining operations performed.

It is an object of the present invention to improve further a vertical lathe of the type described above, in particular increasing its productivity and flexibility.

This and other objects are fully achieved according to the present invention by means of a vertical lathe having the characteristic features defined in the characterizing part of independent Claim 1.

Advantageous embodiments of the invention form the subject-matter of the dependent claims, the contents of which are to be understood as forming an integral and complemen- tary part of the description which follows.

In short, the invention is based on the idea of providing a vertical lathe of the type specified in the preamble of independent Claim 1 with at least one machining unit and at least one counter-head which are mounted on the base, wherein the machining unit comprises a tool-carrying turret or head, the axis of which is oriented horizontally and is located at a distance from the axis of rotation of the drum smaller than the radius of the circumference along which the at least one workpiece-carrying spindle is movable, and movement means designed to move the tool-carrying turret or head relative to the base and to the drum at least along the direction of its axis, and wherein the counter-head comprises a clamping device for clamping a workpiece to be machined, the axis of said clamping device being oriented vertically and being located at a distance from the axis of rotation of the drum equal to the radius of the circumference along which the at least one workpiece-carrying spindle is movable, and motor means for rotationally driving the clamping device about its axis.

Owing to the presence of the machining unit(s) and the counter-head(s), the vertical lathe according to the present invention may for example perform a machining operation by means of the machining unit, or by means of one of the machining units, on the workpiece carried by the counter-head, or by one of the counter-heads, while the workpiece-carrying spindle (or one of the workpiece-carrying spindles) picks up a new workpiece to be machined and while the lathe performs one or more machining operations on this new work- piece using the tools carried by the tool-carrying devices mounted on the base. The vertical lathe according to the present invention is thus able to work as a dual-spindle lathe. Moreover, owing to the presence of at least one counter-head, the vertical lathe according to the present invention is able to carry out machining operations both on one side of the work- piece, using as clamping device the clamping device of the workpiece-carrying spindle (or of one of the spindles) on the drum and as tools the tools carried by the tool-carrying devices on the base, and on the opposite side of the workpiece, using as clamping device the clamping device of the counter-head (or of one of the counter-heads) on the base and as tools the tools carried by suitable tool-carrying devices mounted on the drum. Further characteristic features and advantages of the present invention will emerge clearly from the following detailed description, provided purely by way of a non-limiting example with reference to the accompanying drawings, in which:

Figures 1 and 2 are respectively a side elevation view, partially sectioned, and a top plan view, which show in schematic form a vertical lathe according to an embodiment of the present invention, in which the lathe comprises a dual-axis machining unit with tool- carrying turret; and

Figures 3 and 4 are respectively a side elevation view, partially sectioned, and a top plan view, which show in schematic form a vertical lathe according to a further embodiment of the present invention, in which the lathe comprises a dual-axis machining unit with hob-carrying head. With reference to the drawings, a vertical lathe according to the present invention is generally indicated 10. The vertical lathe 10 (referred to below, for the sake of simplicity, merely as lathe) comprises a base 12, a drum 14 supported by the base 12 so as to be ro- tatable about an axis of rotation z oriented vertically, and motor means (not shown in the drawings since of the type known per se and in any case not relevant for the purposes of the present invention) for rotationally driving the drum 14 about the axis of rotation z. The drum 14 has, mounted thereon, a workpiece-carrying spindle 16 formed as an inverted vertical spindle or pick-up spindle, i.e. a spindle having its axis of rotation (indicated zl) oriented vertically and having its clamping device (indicated 18) directed downwards. In both the embodiments shown in the drawings, the lathe 10 has a single workpiece-carrying spindle 16, but could however have several workpiece-carrying spindles, preferably arranged equally spaced angularly and with the respective axes of rotation zl arranged at the same distance from the axis of rotation z of the drum 14. As a result of the rotation of the drum 14 about the axis of rotation z, the workpiece-carrying spindle 16 also rotates about this axis and therefore its axis of rotation zl moves rigidly together with the drum 14 along a circular path having its centre on the axis of rotation z of the latter and a radius equal to the distance between the axes of rotation z and zl . The workpiece-carrying spindle 16 is also mounted on the drum 14 by means of a slide 20 so as to be displaceable in the vertical direction. The workpiece-carrying spindle 16 further comprises motor means 22 (only schematically shown in Figures 1 and 3) for rotationally driving the clamping device 18 so as to define the cutting speed. Motor means (not shown) for controlling displacement of the slide 20, and along with it of the workpiece-carrying spindle 16, in the vertical direction, are associated with the said slide.

As shown in Figures 2 and 4, a plurality of tool-carrying devices 24 are mounted on the base 12 and can be formed either as rotary tool-carrying turrets, in particular each arranged with its axis of rotation in a horizontal plane (and therefore in a plane perpendicular to the axis of rotation of the drum), or as tool-carrying heads each able to hold a single tool. The tool-carrying devices 24 are located substantially along a circumference (indicated C in Figures 2 and 4) vertically aligned with the circumference along which the axis of rotation zl of the workpiece-carrying spindle 16 moves. Turning of the workpiece carried by the workpiece-carrying spindle 16 is performed using the rotational movement of the drum 14, and therefore of the axis of rotation zl of the said spindle, about its axis of rotation z and the translational movement of the said spindle in the vertical direction in order to control the feeding and depth of the turning operation. While the workpiece-carrying spindle 16, and along with it the workpiece being machined, moves vertically downwards or upwards relative to the tool, it also moves along a circular path having its centre on the axis of rotation z of the drum 14 and radius equal to the distance between the axes of rotation z and zl so as to bring the workpiece into contact with the tool and machine it to the desired shape. The rotary movement of the workpiece-carrying spindle 16 about the axis of rotation z of the drum 14 therefore replaces the translational movement along the X axis of the conventional lathes. The tools carried by the tool-carrying devices 24 may be equally well fixed tools or rotary tools, so that the lathe 10 is also able to perform machining operations other than turning.

The lathe 10 also comprises a counter-head 26 fixed to the base 12 so as to clamp the workpiece to be machined and allow machining thereof by means of tools (not shown) car- ried by tool-carrying devices (also not shown) fixed to the drum 14. In both the embodiments shown in the drawings, the lathe 10 has a single counter-head 26, but could also have a greater number thereof. The counter-head 26 comprises a clamping device 28 for clamping at the bottom a workpiece to be machined. The axis of rotation (indicated z2) of the clamping device 28 is oriented vertically and, as shown in Figures 2 and 4, is located at a distance from the axis of rotation z of the drum 14 equal to the radius of the circumference along which the workpiece-carrying spindle 16 is movable, i.e. equal to the distance between the axis of rotation z of the drum 14 and the axis of rotation zl of the workpiece- carrying spindle 16. The counter-head 26 further comprises motor means (not shown in detail) for rotationally driving the clamping device 28 about its axis of rotation z2. Owing to the counter-head 26, the lathe 10 is able to perform machining operations both on one side of the workpiece, by clamping the workpiece by means of the clamping device 18 of the workpiece-carrying spindle 16, and on the opposite side of the workpiece, by clamping the workpiece by means of the clamping device 28 of the counter-head 26.

The lathe 10 also comprises a machining unit 30 mounted on the base 12. In both the embodiments shown in the drawings, the lathe 10 has a single machining unit 30, but could also have a greater number thereof. The machining unit 30 comprises a tool-carrying turret or head 32, the axis of which (indicated y) is oriented horizontally and is located at a distance from the axis of rotation z of the drum 14 smaller than the radius of the circumference along which the workpiece-carrying spindle 16 is movable, i.e. smaller than the distance between the axis of rotation z of the drum 14 and the axis of rotation zl of the work- piece-carrying spindle 16. The tool-carrying turret or head 32 is supported by a support structure 34 which is mounted on a horizontal slide 36 so as to be displaceable along the direction of the axis y. The horizontal slide 36 has, associated therewith, motor means 38 designed to control displacement of the horizontal slide 36 and, along with it, of the assembly formed by the support structure 34 and by the tool-carrying turret or head 32, rela- tive to the base 12 along the direction of the axis y.

In the embodiment shown in Figures 1 and 2, the tool-carrying turret or head 32 is formed as a rotary turret which is supported rotatably about its axis y and carries a plurality of tools 40. Moreover, in this embodiment, the tool-carrying turret or head 32 is mounted on the support structure 34 by means of a vertical slide 42 so as to be displaceable along a vertical direction (axis z3). The vertical slide 42 has, associated therewith, motor means 44 for controlling the translational movement of the vertical slide 42 and, along with it, of the tool-carrying turret or head 32, relative to the base 12 along the direction of the axis z3. Alternatively, the tool-carrying turret or head 32 could be vertically fixed and therefore have a single degree of freedom of horizontal displacement along the direction of the axis y.

In the embodiment shown in Figures 3 and 4, the tool-carrying turret or head 32 carries a hob 46 by means of which the lathe 10 is able to form teeth both on workpieces carried by the workpiece-carrying spindle 16 and on workpieces carried by the counter-head 26. In this case also, as in the embodiment shown in Figures 1 and 2, the tool-carrying turret or head 32 is mounted on the support structure 34 by means of a vertical slide 42 operated by motor means 44 for moving along the direction of the axis z3. As already mentioned in the introductory part of the description, owing to the presence of the machining unit and the counter-head, the vertical lathe according to the present invention is able to work as a dual-spindle lathe, namely is able to machine simultaneously two workpieces. After being machined on its bottom side by means of the tools carried by the tool-carrying devices mounted on the base, the workpiece being machined may be transferred from the clamping device of the workpiece-carrying spindle to the clamping device of the counter-head. While this workpiece is being machined using the tools mounted on the drum and/or the machining unit, the drum may pick up a new workpiece, clamping it by means of the clamping device of the workpiece-carrying spindle, and perform machin- ing operations on this workpiece using the tools carried by the tool-carrying devices mounted on the base.

Naturally, the principle of the invention remaining unchanged, the embodiments and the constructional details may be greatly varied with respect to those described and illustrated purely by way of a non-limiting example.

Claims

1. Vertical lathe (10) comprising:

a base (12),

a drum (14) supported by the base (12) rotatably about an axis of rotation (z) oriented vertically,

at least one workpiece-carrying spindle (16) formed as an inverted vertical spindle, said at least one workpiece-carrying spindle (16) being mounted on the drum (14) in such a manner that its axis of rotation (zl) is movable together with the drum (14) along a circular path having its centre on the axis of rotation (z) of the drum (14) and in such a manner that said at least one workpiece-carrying spindle (16) is also movable along a vertical direction (zl), and

a plurality of tool-carrying devices (24) mounted on the base (12) so as to allow the respective tools to machine a workpiece carried by the at least one workpiece-carrying spindle (16),

characterized in that

it further comprises at least one machining unit (30) and at least one counter-head (26) which are mounted on the base (12),

wherein each machining unit (30) comprises a tool-carrying turret or head (32), the axis (y) of which is oriented horizontally and is located at a distance from the axis of rotation (z) of the drum (14) smaller than the distance between the axis of rotation (z) of the drum (14) and the axis of rotation (zl) of the at least one workpiece-carrying spindle (16), and movement means (36, 38, 42, 44) designed to move the tool-carrying turret or head (32) relative to the base (12) and to the drum (14) at least along the direction of its axis (y), and wherein each counter-head (26) comprises a clamping device (28) for clamping a work- piece to be machined, the axis (z2) of said clamping device (28) being oriented vertically and being located at a distance from the axis of rotation (z) of the drum (14) substantially equal to the distance between the axis of rotation (z) of the drum (14) and the axis of rotation (zl) of the at least one workpiece-carrying spindle (16), and motor means for rotation- ally driving the clamping device (28) about its axis (z2).

2. Vertical lathe according to Claim 1, wherein said movement means (36, 38, 42, 44) are designed to move the tool-carrying turret or head (32) relative to the base (12) and to the drum (14) also along a vertical direction (z3).

3. Vertical lathe according to Claim 1 or Claim 2, wherein the tool-carrying turret or head (32) is formed as a rotary turret which is supported rotatably about its axis (y) and carries a plurality of tools (40).

4. Vertical lathe according to Claim 1 or Claim 2, wherein the tool-carrying turret or head (32) carries a hob (46) by means of which the lathe is able to form teeth both on workpieces carried by the at least one workpiece-carrying spindle (16) and on workpieces carried by the clamping device (28) of the at least one counter-head (26).