Field of the invention

[0001] The present invention generally finds use in the field of machines and tools for surface machining of precious metals and particularly relates to a device for surface manufacturing and collecting scrap particles of items made of precious metals with collection of scrap particles.

[0002] The invention further relates to a machine tool comprising such device.

Background art

[0003] Machine tools have long been known to be used for carrying out surface machining, such as honing an polishing, on items made of metal materials, namely gold and other precious and non-precious metals, occasionally having very small sizes, such as chain loops and modular elements to be linked together.

[0004] A particular machining operation in the field of jewelry is known as diamond-grinding, and is carried out using rotating tools with diamond points designed to remove a very thin surface layer from the workpiece, thereby leaving grooves that impart high polish and a valuable color effect.

[0005] The tool generally has the shape of a disc and is located within a work area that is isolated from the outside environment by a box-like structure.

[0006] Such box-like structure has the purpose of limiting the ingress of impurities into the work area, and the dispersion of scrap having different particle sizes into the outside environment.

[0007] The scrap is later recovered by the box-like structure using appropriate extraction systems, and considerable labor effort, to be melted again and reused during the next machining steps.

[0008] A first drawback of these arrangements is that, in order to recover the gold scrap, the operator is required to shut down the machine and open the box-like structure to draw in scrap by a manual device. [0009] Due to this drawback, the overall work time will be increased and the operator will not be able to recover all the scrap collected in the box-like structure.

[0010] A further drawback is that scrap tends to deposit on the parts of the machine inside the box-like structure, with the risk that they may be damaged or jammed.

[0011 ] In view of at least partially obviating these drawbacks, collectors have been provided for continuous recovery of scrap generated by machining metal items, which can be coupled to machining tools, namely disk-type tools.

[0012] US 5,951 ,21 9 discloses a collector device for collecting scrap, particularly gold powder and particulates, which comprises a rigid frame, with a semicircular gap, which is adapted to be laid on a rotating disk-shaped tool for machining gold items.

[0013] The frame comprises a substantially vertical bottom wall against which the scrap produced by the rotating tool during machining is propelled, and a duct for collecting it, which is located below the bottom wall and has an opening formed in the bottom wall of the frame.

[0014] One drawback of this arrangement is that this drawback has a particularly large size and requires a very complex installation procedure on existing machine tools.

[0015] A further drawback is that, due to the thrust imparted to the scrap by the rotation of the tool, some of the scrap tends to build up at the bottom wall of the frame. Here again, in order to empty the scrap collector, the operator will be required to shut down the machine and manually remove the scrap, which will lead to the typical drawbacks of the prior art.

[0016] This problem might be solved by installing appropriate blowing and/or extraction means, for urging and/or extracting scrap from the bottom wall toward the opening of the duct, which will increase the complexity of the device.

Technical Problem

[0017] In view of the prior art, the technical problem to be solved is to provide a device for machining items made of precious metal materials and recovering scrap therefrom, for recovery and reuse in the production cycle.

Disclosure of the invention

[0018] A general object of the present invention is to solve the aforementioned technical problem and obviate the above drawbacks, by providing a device for surface manufacturing and collecting scrap particles of items made of precious metals generated by surface manufacturing thereof, that is highly efficient and relatively cost-effective.

[0019] A particular object is to provide a device as discussed above, that can recover and reuse precious metal scrap.

[0020] Another object of the present invention is to provide a device as discussed above, that can be easily installed on existing disc-type machining tools.

[0021 ] A further object of the present invention is to provide a device as discussed above that has very small dimensions.

[0022] A further object of the present invention is to provide a device as discussed above that is particularly simple and does not require extraction and blowing systems for recovery and collection of scrap.

[0023] Another object of the present invention is to provide a device as discussed above, that can recover and collect substantially all the scrap from the items being machined.

[0024] A further object of the present invention is to provide a machine tool as discussed above in which the machining tools can be easily accessed by an operator without having to remove the collector.

[0025] These and other objects, as more clearly explained below, are fulfilled by a device for machining items made of precious materials and collecting scrap particles therefrom as defined in claim 1 , which comprises a disk-shaped tool designed to be mounted to a spindle of a machine tool, and at least one collector for scrap, which is mounted to an outer peripheral area of the tool.

[0026] The collector comprises a substantially tubular conveyor shell, which is adapted to enclose the outer peripheral area of the disk-shaped tool and to convey the scrap ejected outwards by the tool due to centrifugal force.

[0027] According to a peculiar characteristic of the invention, the collector comprises a closed container for collecting scrap, which is connected to the conveyor shell via a connecting duct and has a side wall for confining scrap in the container.

[0028] Due to this characteristic, the collector is able to collect scrap and prevent it from falling back before being transferred into the container.

[0029] According to a further aspect, the invention provides a machine tool as defined in claim 1 2, which comprises the device as discussed above.

[0030] Advantageous embodiments of the invention are defined in accordance with the dependent claims.

Brief description of the drawings

[0031 ] Further characteristics and advantages of the invention will be more apparent from the detailed description of a few preferred, non-exclusive embodiments of a device for surface manufacturing and collecting scrap particles of items made of precious metals according to the invention, which are described as non-limiting examples with the help of the annexed drawings, in which:

FIG. 1 is a perspective view of a device of the invention, when coupled to the machine tool comprising a disk-shaped machining tool;

FIG. 2 is a side view of the device and the machine of Fig. 1 ;

FIG. 3 is a front view of the device and the machine of Fig. 1 ;

FIG. 4 is a bottom view of the device and the machine of Fig. 1 .

Detailed description of a preferred exemplary embodiment

[0032] Referring to the aforementioned figures, numeral 1 ' generally denotes and designates a device for machining items O made of precious metals and collecting scrap particles P therefrom.

[0033] The device 1 ' comprises at least one disk-shaped tool 2 designed to be mounted to a spindle of a machine tool, e.g. a diamond-grinding machine, not shown, for surface machining of metal items O in a given work area A and a collector 1 for scrap P.

[0034] The tool 2 is mounted to the spindle that rotates about a substantially transverse axis X at the free end of a support arm 3.

[0035] Of course, the collector 1 of the invention may be also used in machines other than the diamond-grinding machine, having rotating disk- shaped machining tools, without departure from the scope of the present invention.

[0036] The workpiece to be machined O is supported in the work area A and on opposite sides from a vertical plane π that extends through the workpiece being machined by at least one pair of push rods 4.

[0037] While the figures show a single disk-shaped tool 2, the machine may be equipped with multiple tools 2 of the same type to carry out further machining on the same workpiece O.

[0038] According to a peculiar aspect of the invention, the collector 1 comprises a substantially tubular sector-shaped conveyor shell 5 which is adapted to enclose an outer peripheral area 6 of a disk-shaped tool 2 and to collect the scrap P ejected outwards by the tool 2 due to centrifugal force.

[0039] A closed container 7 for collecting scrap P and a connecting duct 8 disposed between the conveyor shell 5 and the container 7, as shown in FIGS. 1 to 4, are also provided.

[0040] The conveyor shell 5 is adapted to at least partially enclose the disk-shaped tool 2 and has, at its inner peripheral portion 9, a slot 1 0 for the passage of the tool 2.

[0041 ] Furthermore, the edges 1 1 of the slots 10 lie on substantially parallel planes at a minimum distance d from the opposite faces 1 2 of the rotating tool 2 to prevent scrap P from falling back before being transferred to the container 7.

[0042] With this arrangement, the scrap P generated by machining the metal workpiece O may be substantially entirely conveyed from the work area A to the container 7, without requiring extraction and/or blowing means, simply using the centrifugal force of the rotating tool 2.

[0043] Conveniently, the collector 1 may be fitted to the disk-shaped tool 2 to enclose the upper portion of the outer peripheral area 6.

[0044] Possibly, the collector 1 may be also fitted to the lower portion of the outer peripheral area 6 of the tool 2 to collect the scrap P, provided that its direction of rotation is reversed.

[0045] As shown in FIG. 3, the minimum distance d is selected as being approximatively equal to the maximum size of the scrap P and may range from 0.20 to 0.30 mm, and be preferably about 0.25 mm.

[0046] Advantageously, the conveyor shell 5 may be formed using a metal plate 1 3 which is folded and shaped to a substantially elliptical or circular cross section, which is broken at the slot 1 0, as shown in FIGS. 1 , 3 and 4, and with a curved inner surface 14.

[0047] The inner surface 14 will have such a shape that the scrap P propelled by the rotating tool 2 will hit such surface at an inclination angle a relative to a direction tangent to the tool 2 and will be conveyed toward the container 7.

[0048] Conveniently, the collector 1 may be coupled to the disk-shaped tool 2 such that the ratio of the inclination angle a to the thickness of the tool 2 is 25 3 mm.

[0049] As best shown in FIGS. 1 and 2, the connecting duct 8 or the shell 5 may be fixed to the arm 3 of the disk-shaped tool 2 using at least one support bracket 1 5.

[0050] The bracket 1 5 may have a curved portion 1 6 coupled to the connecting duct 8 or the shell 5, and a pair of straight portions 1 7 fixed to the arm 3 of the tool spindle, on opposite sides with respect to the opposite faces 12 of the tool 2, by means of appropriate connecting members 1 8.

[0051 ] Due to this arrangement, in combination with the particular shape of the conveyor shell 5 the collector 1 may have a limited overall size, and may be mounted in a very simple manner even to existing disk-shaped tools 2.

[0052] Furthermore, the bracket 1 5 may be placed in a different position relative to the arm 3 of the tool 2, such that the outer peripheral area 6 of the latter enclosed by the shell may be changed, by displacement of the connecting members 18.

[0053] The connecting duct 8 may have an opening 20 formed in its inner peripheral portion 21 , at its longitudinal end portion 1 9 proximate to the shell 5, for the passage of the tool 2,

[0054] On the other end, the longitudinal end portion 22 of the connecting duct 8 proximate to the container 7 is closed, with no openings at its inner peripheral portion 21 , and may be connected to an inlet hole 23 of the container 7 through appropriate sealing means, not shown.

[0055] Particularly, the longitudinal portion 1 9 of the connecting duct 8 with the opening 20 will be adapted to cover the outer peripheral area 6 of the tool 2, whereas the closed longitudinal portion 22 thereof will extend from the edge 24 of the tool 2 to the container 7.

[0056] At the longitudinal end portion 19 proximate to the conveyor shell 5, the connecting duct 8 may have a cross section that mates the section of the shell 5.

[0057] Thus, an even, seamless connection may be obtained between the duct 8 and the shell 5 and between the opening 20 and the slot of the latter, to facilitate the transfer of scrap P from the shell 5 to the container 7.

[0058] Like the shell 5, the connecting duct 8 also has an inner surface 25 connected to the opening 20 and adapted to be hit by the scrap P ejected from the shell 5 to convey it into the container 7.

[0059] The latter may comprise a substantially rigid side wall 26 as shown or, in an alternative embodiment, a substantially flexible side wall.

[0060] In the first embodiment, the rigid wall 26 has an exhaust hole, not shown, to provide communication of the container 7 with the outside environment to avoid exhaust back pressure during transfer of the scrap P.

[0061 ] In the alternative embodiment, the flexible wall is substantially porous with pores smaller than the particle size of the scrap, to retain the scrap within the container and avoid collector filling resistances.

[0062] In a further aspect, the invention relates to a diamond-grinding machine tool as described above, not shown, for surface machining of items O made of precious and non-precious metal materials, which comprises at least one disk-shaped tool 2 mounted to a rotating spindle to carry out machining of the workpiece in the work area A. [0063] The diamond-grinding machine further comprises at least one collector 1 as described above, which is mounted to an outer peripheral area 6 of a respective tool 2, distal from the work area A, to collect and recover substantially all the scrap particles P from the items O being machined.

[0064] Advantageously, the circular edge 24 of the tool 2 may have a predetermined number of cuts 27 for increasing the amount of scrap P ejected toward the shell 5 due to centrifugal force.

[0065] The machining and scrap-collecting device and the machine tool of this invention are susceptible to a number of changes or variants, within the inventive concept disclosed in the appended claims.

[0066] While the machining and scrap-collecting device and machine have been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

Industrial applicability

[0067] The present invention may find application in industry, because it can be produced on an industrial scale in factories within the field of machining of precious and non-precious metals.