GB2096500A - Faceting machine - Google Patents

Abstract

A faceting machine includes two motors (17, 8) of the "step by step" type, on whose shafts there are respectively mounted a workpiece holder (18) and a tool holder (7), both having a facility for universal adjustment. This makes it possible to effect a wider range of settings and to vary at will the ratio between the speed of rotation of the tool holder and that of the workpiece holder. <IMAGE>

Description

SPECIFICATION Faceting machines The present invention relates to a faceting machine capable of working surfaces having any degree of inclination with respect to the tool.

It is known that the faceting of a piece at regular intervals is not a simple operation. In the commonly used faceting machine the piece is mounted on a rotary support, linked by means of gearing or other mechanical connections to a tool holder, which rotates as well.

The use of mechanical links makes it difficu It to effect workings requiring a different reciprocal positioning or inclination between the tool holder and the workpiece holder. In addition, the use of such links (called "dividing heads") entails a considerable loss of time whenever the gears are to be replaced to vary the ratios between the speeds of rotation. In the lately manufactured faceting machines the displace menttaking place between tool holder and workpiece holder is controlled by opto-electronic systems; however, due to the delay of the transductors, an undesirable double score is often present on the pieces being worked.

The present invention provides for a faceting machine equipped with a couple of "step by step" motors, connected to each other by proper electronic devices of known type, whose shafts carry respectively the tool holder and the workpiece holder.

These motors, which are of extremely small size and need only a series of electrical contacts to be connected to other apparatus, can be set at any position or inclination during working.

This allows the working of pieces of any shape, or to provide the surfaces to be worked with a series of scores having no matter what orientation.

The characteristics of the "step by step" motors, which are actioned by a series of impulses, are such that it is possible to determine the respective speeds of rotation according to any required ratio, and this is achieved with the maximum precision thanks to highly sophisticated low cost pulse-generating machines.

An embodiment of the present invention will now be described with reference to the accompanying drawings, in which : Figure 1 is a perspective view of a faceting machine according to the invention; Figure 2 is a perspective view of a detail of the faceting machine.

With reference to Figure 1, a faceting machine according to the invention consists essentially of a base 1 to which there are fixed a support 2 of a tool-holding head and a support 4 of a workpiece holding unit. In Figure 1 there is also represented at one side of the base 1 a unit 6 holding electronic devices of known type controlling the step by step motors. The tool holder 7 is mounted on the shaft of a motor 8 of the "step by step" type. Motor 8 (which can rotate around a horizontal axis A-A) is mounted on a support 9 which is in turn mounted inside a head 10 and can shift vertically.

By means of keys 11 or the like, support 9 can be set at any height, and to give it any desired inclination in respect of the piece being worked.

The latter is supported by the following elements.

On support 4, secured to base 1, there are mounted a couple of slides 13-14 movable along a couple of orthogonal, essentially horizontal axes. On these slides there is mounted a base 15, rotatable around a vertical axis, and carrying an arm, at the upper end of which there is a head 16; said head 16 is rotatable around a horizontal axis and lockable in any position; in respect of head 16 a "step by step" motor 17, whose shaft carries a workpiece holder 18, can move and be set at any desired point. Slides 13-14 serve for translating the piece to be worked under the tools, while the rotatable head 16 permits adjustment of the inclination thereof with respect to the tools.

The working of the machine is as follows : Once the tools are mounted on tool holder 7, and the piece to be worked is secured to workpiece holder 18,slides 13-14 are shifted untiltheworkpieceis exactly under the tools. By rotating head 16, the workpiece is given the desired inclination; the same is then restored to the desired height by translating the "motor 17-tool holder 18" unit along head 16.

Head 3 is then rotated about its own vertical axes to obtain scores in the required direction, and is clamped by means of devices 12. Then support 9 is lowered and clamped by means of keys 11. At this stage, it is enough to energise the electronic devices held in unit 6 to adjust at will the ratio between the speed of rotation of the tool holder and that of the workpiece holder, after which the working can take place.

By using a couple of independent motors it is thus possible to give the tool holder and the workpiece holder axes any desired inclination, without the drawbacks caused by mechanical connections, if any.

By using, in particular, a couple of motors of the "step by step" type, the ratios of the speeds of rotation can be actually unlimited, these variations being achieved with the maximum precision.

1. Afaceting machine wherein the tool holder and the workpiece holder are each mounted on the shaft of an individual motor, these motors being in turn mounted on supports, allowing any desired inclination thereof.

2. A faceting machine according to claim 1, wherein the motors are of the "step by step" type.

3. A faceting machine constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Faceting machines The present invention relates to a faceting machine capable of working surfaces having any degree of inclination with respect to the tool. It is known that the faceting of a piece at regular intervals is not a simple operation. In the commonly used faceting machine the piece is mounted on a rotary support, linked by means of gearing or other mechanical connections to a tool holder, which rotates as well. The use of mechanical links makes it difficu It to effect workings requiring a different reciprocal positioning or inclination between the tool holder and the workpiece holder. In addition, the use of such links (called "dividing heads") entails a considerable loss of time whenever the gears are to be replaced to vary the ratios between the speeds of rotation. In the lately manufactured faceting machines the displace menttaking place between tool holder and workpiece holder is controlled by opto-electronic systems; however, due to the delay of the transductors, an undesirable double score is often present on the pieces being worked. The present invention provides for a faceting machine equipped with a couple of "step by step" motors, connected to each other by proper electronic devices of known type, whose shafts carry respectively the tool holder and the workpiece holder. These motors, which are of extremely small size and need only a series of electrical contacts to be connected to other apparatus, can be set at any position or inclination during working. This allows the working of pieces of any shape, or to provide the surfaces to be worked with a series of scores having no matter what orientation. The characteristics of the "step by step" motors, which are actioned by a series of impulses, are such that it is possible to determine the respective speeds of rotation according to any required ratio, and this is achieved with the maximum precision thanks to highly sophisticated low cost pulse-generating machines. An embodiment of the present invention will now be described with reference to the accompanying drawings, in which : Figure 1 is a perspective view of a faceting machine according to the invention; Figure 2 is a perspective view of a detail of the faceting machine. With reference to Figure 1, a faceting machine according to the invention consists essentially of a base 1 to which there are fixed a support 2 of a tool-holding head and a support 4 of a workpiece holding unit. In Figure 1 there is also represented at one side of the base 1 a unit 6 holding electronic devices of known type controlling the step by step motors. The tool holder 7 is mounted on the shaft of a motor 8 of the "step by step" type. Motor 8 (which can rotate around a horizontal axis A-A) is mounted on a support 9 which is in turn mounted inside a head 10 and can shift vertically. By means of keys 11 or the like, support 9 can be set at any height, and to give it any desired inclination in respect of the piece being worked. The latter is supported by the following elements. On support 4, secured to base 1, there are mounted a couple of slides 13-14 movable along a couple of orthogonal, essentially horizontal axes. On these slides there is mounted a base 15, rotatable around a vertical axis, and carrying an arm, at the upper end of which there is a head 16; said head 16 is rotatable around a horizontal axis and lockable in any position; in respect of head 16 a "step by step" motor 17, whose shaft carries a workpiece holder 18, can move and be set at any desired point. Slides 13-14 serve for translating the piece to be worked under the tools, while the rotatable head 16 permits adjustment of the inclination thereof with respect to the tools. The working of the machine is as follows : Once the tools are mounted on tool holder 7, and the piece to be worked is secured to workpiece holder 18,slides 13-14 are shifted untiltheworkpieceis exactly under the tools. By rotating head 16, the workpiece is given the desired inclination; the same is then restored to the desired height by translating the "motor 17-tool holder 18" unit along head 16. Head 3 is then rotated about its own vertical axes to obtain scores in the required direction, and is clamped by means of devices 12. Then support 9 is lowered and clamped by means of keys 11. At this stage, it is enough to energise the electronic devices held in unit 6 to adjust at will the ratio between the speed of rotation of the tool holder and that of the workpiece holder, after which the working can take place. By using a couple of independent motors it is thus possible to give the tool holder and the workpiece holder axes any desired inclination, without the drawbacks caused by mechanical connections, if any. By using, in particular, a couple of motors of the "step by step" type, the ratios of the speeds of rotation can be actually unlimited, these variations being achieved with the maximum precision. CLAIMS

1. Afaceting machine wherein the tool holder and the workpiece holder are each mounted on the shaft of an individual motor, these motors being in turn mounted on supports, allowing any desired inclination thereof.

2. A faceting machine according to claim 1, wherein the motors are of the "step by step" type.

3. A faceting machine constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.