IL292257B1 - Gemstone machining center and/or method - Google Patents

Description

GEMSTONE MACHINING CENTER AND/OR METHOD TECHNICAL FIELD[001] Embodiments of the invention relate to a gemstone machining center and/or method, in particular for performing substantial automatic machining.

BACKGROUND [002] Machining facets on gemstones such as diamonds requires attention to various aspects. For example, the hardness of the diamond and a diamond’s grain should be taken into consideration, where grain dictates that e.g. a facet should be presented to a scaife in such a way that the direction of movement of the scaife forms an appropriate angle with a given crystallographic or grain direction in that facet.

[003] Typically when working facets a machining member contacts the gemstone being worked in a working plane, where such machining member may be a polishing member in the form of a wheel or disc of a scaife made of thick cast iron. A gemstone polishing member includes measures for holding and driving a moving machining member and at least one polishing machine.

[004] While working facets of a gemstone, the stone is typically held in a relative long-shaped holder with an axis normally parallel with that of the stone. Thus when working a facet, the holder may have its axis inclined to the working plane at an angle that defines the angle of the facet.

[005] GB2037196 describes a gemstone polishing machine that has a rotatable grain shaft for mutually orientating a gemstone and a rotating scaife. A signal dependent on drag between the stone and scaife is generated and a drive rotates the grain shaft to orientate the stone so as to give a high drag. Drag is generally related to polishing efficiency and the stone can thus be polished efficiently. In an arrangement a signal dependent on the rate of stone feed is generated to confirm efficient polishing.

SUMMARY[006] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[007] In an embodiment there is provided a gemstone machining center comprising: a set-up station adapted to deliver onwards loaded-dops each comprising a dop holder and a gemstone bonded to the dop holder, a bruting/cutting station for receiving loaded-dops from the set-up station, and at least one polishing station for receiving gemstones after being detached from their dop holders.

[008] The set up station may include automatic and/or manual steps for setting up a gemstone on a dop holder, and may include moving dop holders with gemstones upon a conveyor between various stations, such as curing stations, where the gemstones bond to their respective dop holders to form loaded-dops. [009] In an embodiment there is also provided a capsule for securing a gemstone for use in a gemstone machining center, comprising a dop-holder and a gemstone secured to an upper tip of the holder.

[010] Such capsule may be formed in the set up station, and may function to house the loaded dop until transferred for further machining of its gemstone in a machining center, possibly of a transfer type.

[011] In an embodiment there is also provided a method for transferring a gemstone between machining/polishing stations comprising the steps of: providing a source machining/polishing station initially holding onto a gemstone, providing a destination machining/polishing station comprising a dedicated seat arranged for receiving the gemstone, urging at least one of the source and destination 30 machining/polishing stations towards each other to bring the gemstone into contact with the dedicated seat, and applying suction at the dedicated seat to at least temporarily hold onto the gemstone.

[012] Such handling and transferring ay permit moving a gemstone between various machining stations and forming preferably automatically required shapes I the gemstone.

[013] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES[014] Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying figures, in which:

[015] Fig. 1A schematically shows a perspective view of a gemstone machining center in accordance with an embodiment of the present invention; [016] Fig. 1B schematically shows a top view of the gemstone machining center of Fig. 1A;

[017] Figs. 2A and 2B schematically show various views of an embodiment of a loading and curing station generally marked by the dashed rectangle indicated as II in Fig. 1B;

[018] Figs. 3A to 3C schematically show various views of a capsule according to an embodiment of the present invention holding in place a gemstone rough cemented to a dop holder;

[019] Figs. 4A to 4D and Fig. 8 schematically show various views of embodiments of a bruting/cutting station generally marked by a dashed rectangle indicated as IV in Fig. 1B; 30

[020] Figs. 5A to 5M , 9A to 9C and 10 schematically show various views in particular of embodiments of a polishing station of the invention, such as that generally marked by the dashed rectangle indicated as V or VI in Fig. 1B;

[021] Fig. 6 schematically shows one possible example of transfer of a gemstone from one polishing station to a possible other polishing station, such as from that marked by dashed rectangle V to the other marked by dashed rectangle VI in Fig. 1B;

[022] Figs. 7A to 7D schematically show in Figs. 7A, 7B and 7C one possible example of transfer of a gemstone from first or second polishing station to a grading and packaging station, and in Fig. 7D an embodiment of a storage buffer station – where both the grading and packaging station and the storage buffer station are generally marked by the dashed rectangle indicated as VII in Fig. 1B;

[023] Figs. 11A and 11B schematically illustrate an embodiment of a dressing assembly possibly used in conjunction with at least certain embodiments of gemstone machining centers;

[024] Figs. 12A to 12 Bprovide more representative side and section views, respectively, of a gemstone possibly suitable to be secured to at least certain machining stations;

[025] Figs. 13A to 13G schematically show certain embodiments of dedicated seats suitable for use in at least certain machining center embodiments; and [026] Fig. 14 schematically shows an embodiment of a clamp suitable for clamping a gemstone to at least certain dedicated seat embodiments.

[027] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated within the figures to indicate like elements.

DETAILED DESCRIPTION[028] While machining e.g. facets on gemstones, substantial difficulties may be encountered with diamonds in particular due to their extreme hardness, mechanical, 30 physical and/or chemical properties. Thus, despite being related to gemstones in general, the various embodiments herein at least in certain cases may be described with reference to diamonds, since machining techniques used for diamonds typically can be used for any other (natural or synthetic) gemstones.

[029] Attention is first drawn to Figs. 1A and 1B illustrating a transfer machine system 10 used for gemstone machining, grading and packaging according to an embodiment of the present invention. System 10 is generally of a so-called "transfer" machine type including a combination of individual machining stations and/or heads, arranged in a sequence and connected by work transfer devices – thus permitting a maximal amount of operations to be performed possibly in parallel at high production rates. System 10 here includes a main machining cell 12, a pressurized gas source and an electric cabinet 16 both in communication with machining cell 12. [030] Attention is drawn to Figs. 2 and 3 illustrating a first possible set-up station 18 of system 10, here including loading and curing stages. Set-up station 18 is generally indicated in Fig. 1B by the dashed-rectangle II. Station 18 is arranged to receive capsules 20 that include each a gemstone (possibly a rough, table machined gemstone). In Figs. 3A to 3C an embodiment of such a capsule 20 is illustrated including a gemstone 24 cemented at its table 241 to a dop holder 22. Dop holder may be fitted at its lower side to a base 26 of the capsule, and capsule 20 may further include a sleeve 28 and a retaining cap mechanism 30. Dop holder 22 (see enlarged circled view at right-hand side of Fig. 3C) in one embodiment may be flat at its upper side with a small recess 23 formed therein for containing a bit of adhesive/cement for attaching to a gemstone (see enlarged circles at left-hand side of Fig. 3C) and possibly also to assist in obtaining desired geometric relations between the gemstone's orientation and the dop's shank/axis.

[031] Sleeve 28 may be assembled over dop holder 22 in order to surround the gemstone. Sleeve 28 in one example may be arranged to include windows 2 extending sideways through the sleeve to permit viewing and/or physical access to the gemstone from the outside. Retaining cap mechanism 30 may be assembled on top of the sleeve and may be arranged to include an abutment member (or plunger) 30 301 for securing the gemstone within the capsule. In this example, the abutment member may be spring biased downwards to bear against the gemstone from above in order to support the gemstone against dop holder 22 at least during a curing process within station 18.

[032] With attention drawn back to Fig. 2A and 2B, station 18 may be seen including a loading section 181 where capsules 20 are arranged/assembled/placed on a conveyer 17 of the station. Such conveyer 17 may be arranged to carry the capsules, inter alia, through a curing section 182 (possibly in form of a furnace) of system 18.

Loading section 181 may be exposed to an exterior of main machining cell 12 as seen at the upper side of Fig. 1B. Arrangement/placement of a capsule 20 at the loading section may possibly be manually or automatically (e.g., by robotic means) at section 181, which may in this example be also easily accessible from outside of cell 12. [033] From loading section 181 the capsules are accordingly carried towards and through curing section 182 where the adhesive/cement attaching each gemstone to its dop holder undergoes hardening. Capsules exiting the curing section may then be arranged to pass via first, second and possibly third manipulators 32, 34, 35. The first manipulator 32 may be arranged to remove the retaining cap mechanism 30 and sleeve 28 off each capsule 20 into a sleeve collection tray 11, the second manipulator 34 may be arranged to remove each dop holder 22 with its attached gemstone off the base of the capsule and the third manipulator 35 may be arranged to remove the base of the capsule 26 off the conveyor into a base collection tray 15. Conveyer 17 may then continue to advance its empty chain-links/elements/pockets back towards the loading section 181 where new capsules 20 may be loaded into the station. From hereon a dop holder with a gemstone attached/cemented to it (either by the method discussed in relation to system 18 or any other method) - may be referred to herein as a loaded-dop. [034] Attention is drawn to Figs. 4A to 4D illustrating an embodiment of a bruting/cutting station 36 generally marked by dashed-rectangle IV in Fig. 1B.

Bruting/cutting station 36 includes an incoming hub 38 for receiving loaded-dops.

Such loaded-dops may arrive from system 18 e.g. via manipulator 34. In addition, or 30 alternatively, loaded-dops may be prepared by means other than those in system and may be placed in hub 38 by any other means, automatic means (e.g., by robotic means), manual means (etc.).

[035] Provision of loading hub 38 may be useful, inter alia, in serving as a so- called buffer zone for storing at least momentarily loaded-dops until machining means within bruting station 36 become available. Since, gemstones on different dops may be different and/or require different machining – the timing of the machining process of each gemstone may be different – thus making hub 38 useful in providing a zone where loaded-dops can be arranged to await in queue for machining cycle.

[036] Bruting/cutting station 36 in addition includes a holder center 40 possibly functioning as an automatic gemstone centering and driving mechanism. Bruting/cutting station 36 in addition includes a number of bruting/cutting stations, as desired. In the presented example, a first girdle bruting/cutting station 42 and a second pavilion bruting station 44 are located about holder center 40. Holder center 40 may be arranged to rotate about an axis R by possibly being placed on a servo- driven rotary table 401. Holder center 40 includes a pneumatic or hydraulic operated dead-length collet block 402 for clamping loaded-dops. The dead-length collet block may be arranged to generally clamp loaded-dops about a holder axis H, which may be generally perpendicular to axis R of rotation.

[037] Holder 40 may include a rotary union 37 (see indicated in Fig. 5A) that allows for rotation of parts within the holder while providing a seal between stationary supply passages (such as pipes or tubing) e.g. communicating hydraulics to the holder and rotating parts within the holder. Such rotary union (although not marked e.g. in Figs. 4) may be understood to be utilized in other machining stations herein, where allowance for rotation of parts is required while providing a seal between stationary supply passages (such as in polishing station 48 etc.).

[038] Holder 40 also includes a sensor 403 located here above a location where the gemstone is arranged to be placed when its dop is clamped within holder 40.

Sensor 403 may be an optical sensor such as a CCD camera (or the like) for viewing and/or sensing the gemstone's position and/or orientation.

[039] Sensor 403 may be arranged to provide sensed data that can be used for computing geometrical data (in 2D or 3D) of the gemstone's position and/or orientation when it is being held in the collet and/or during its machining/bruting process. Data gathered by sensor 403 may assist to determine when an axis of symmetry of a target shape of the current gemstone is generally aligned with axis H.

Such alignment may be needed since a rough gemstone to be machined may fitted in- accurately to its dop, e.g. due to it being fitted manually to the dop - so that the axis of symmetry of the target shape of such gemstone may not necessary be aligned with the dop's axis of symmetry. Data gathered by sensor 403 may also assist to determine when a target shape in a certain area of the gemstone being machined has been obtained and by that e.g., stop the machining of that operation.

[040] Sensor 403 may also be used for monitoring presence of the gemstone during machining - to ensure e.g., that it did not unintentionally detach from its dop.

Since sensor 403 in the examples illustrated is located above the gemstone 24, at least in the top views provided in Figs. 4B to 4D, indication of where sensor 403 is located renders also indication as to where the gemstone clamped in holder 40 is located.

Therefore, in these figures dual indication of 403/24 may be used. [041] Attention is drawn to the enlarged view at the upper side of Fig. 4A (providing a view of cross section X-X) to demonstrate one possible option for implementing a centering mechanism 400 (generally seen within the dashed-ellipse), suitable for centering a gemstone of a loaded-dop that is fitted to holder center along axis H.

[042] Pneumatic and/or hydraulically operated dead-length collet block 402 may be coupled via a manifold cylinder-block 401 with a widening 1 at a rear side to a centering hub 404. Centering hub 404 in this example includes a shoulder 2 at its forward side and a disk 4 may be arranged to bear forwardly against widening 1 of manifold cylinder-block 401 in order to press its widening 1 against shoulder 2 and by that lock the location and orientation of manifold cylinder-block 401 and 30 consequently of the dead-length collet block and loaded-dop relative to centering hub 404 - within holder center 40. Forward bearing at the disk 4 against chassis 401 in the illustrated example may be obtained by a hydraulic piston 406.

[043] The single acting hydraulic piston 406 may be arranged to urge forwardly and rearwardly disk 4 at a rear side of a possible series of Belleville washers/coned- disc springs, here illustrated by one Belleville washer 3 and by that urge loading and ease of loading of Belleville washer 3 by reducing and increasing respectively a spacing 6 formed between disk 4 and a disk 7 pressed by Belleville washer 3 against a rear side of chassis 401. During a centering operation piston 406 may be retracted backwards, and by that spacing 6 may be increased resulting in unloading of Belleville spring 3 while still maintaining sufficient pressing force against disk 7 and by that formation of friction force between widening 1 and shoulder 2 to temporary hold substantially in place manifold cylinder-block 401 against centering hub 404. A peripheral spacing 5 present between an outer periphery of widening 1 and an inner face of centering hub 404 - may permit urging relative movements between manifold cylinder-block 401 and centering hub 404.

[044] A centering operation cycle may include several optional steps including the following. First a fixation mechanism 405 may be urged forward by possibly several peripheral single-acting hydraulic pistons 407 – thereby urging cylinder-block 401 to be generally centered and concentric with centering hub 404. Attention is additionally drawn to Fig. 8 schematically illustrating a cross sectional taken along a plane generally similar to cross section X-X in Fig. 4A (possibly a plane slightly rotated relative to plane X-X). This view reveals a possible compression springs 4 arranged to urge fixation mechanism 405 (indicated e.g. in Fig. 8 and 4A) to move backwards when hydraulic pressure urged by single-acting hydraulic pistons 407 may have been stopped, leaving peripheral spacing 5 clear. At this state when a location and orientation of manifold cylinder-block 401/dead-length collet block 402 may be known and/or obtained - a possible first scan of the gemstone can be executed. A loaded dop fixed to block 401 may be rotated about axis H e.g. by 360 degrees and scanned in aim to identify the desired movements of manifold cylinder-block 401 30 relative to centering hub 404, necessary for required/targeted alignment/centering of the loaded-dop in relation to axis H, e.g. angular and radial movements. Such movements, in one non-binding example, may be urged by coordinated and controlled operation in this example of two mechanisms: a rotating spindle 21 and a gripper where both may be driven by servo motors 20 and 60, respectively (see indicated at the lower main part of Fig. 4A) that may be respectively arranged to turn centering hub 404 around axis H in order to possibly locate it in a desired angular position in order to possibly urge block 401 in radial directions in relation to hub 404 using gripper 66 mechanism. Gripper 66 here may urge movements in directions along an axis/direction generally orthogonal to axis H. Centering of a loaded-dop may be obtained by combined incremental adjustments, that may include urging a controlled angular rotating of centering hub 404 around axis H and then urging a controlled linear movement by gripper 66 mechanism (and so on) - until image processing of signals arriving from sensor 403 confirm a required/targeted alignment/centering of the loaded-dop in relation to axis H is reached.

[045] Once such centering is generally met – in the example illustrated - piston 406 may be manipulated to urge disk 4 to move forwardly and by that increase the friction force between widening 1 and shoulder 2, which now holds manifold cylinder-block 401 against centering hub 404 in a fixed place at its last position (where e.g. a gemstone target may now be centered). Monitoring and control of the incremental steps taking place in order to form the centering of the loaded-dop relative to axis H may be facilitated by, e.g. image processing of, information gathered by sensor 403 viewing/sensing the gemstone fitted to the loaded-dop (notably, besides vision other sensing technologies may be applied by sensor 403).

[046] Attention is additionally drawn to Fig. 4B illustrating a first possible step of machining within bruting/cutting station 36. In this first possible step – holder may be rotated about axis R to place collet block 402 adjacent incoming hub 38. A manipulator 46 of station 36 may be arranged for picking loaded-dops out of hub and placing them within dead-length collet 402. Clamping and unclamping of dops within dead-length collet block 402, in one example, may be performed by fluid 30 pressure (e.g. air or hydraulic pressure) urging transition of the dead-length collet block 402 between clamped and un-clamped states.

[047] Once a loaded-dop is clamped within holder 40 and has been centered as described above, the mechanism may be rotated about axis R to the positions of different bruting/cutting sites/terminals. Thanks to the combination of coordinated movement between servo-controlled rotation movement of gemstone 24 around H- axis and servo-controlled linear/rotational movements along/about respective axes B/ S of the bruting stations, cutting/machining of a gemstone may be performed along a variety of profiles.

[048] In the illustrated example, as seen in Fig. 4C, holder 40 may stop its rotation around R-axis at girdle bruting station 42 for girdle machining of the current gemstone 24. After completion of the girdle, holder 40 may be rotated about axis R once again to the position seen in Fig. 4D at pavilion bruting station 44 for a pavilion machining of the current gemstone 24. Bruting/cutting at each respective site 42, may be performed while advancing the respective station along its axis B to a location where initial contact between gemstone 24 and respective grinding wheel occurs.

Then the respective station may undergo additional movements along its axis B - bringing the gemstone at the loaded-dop into and out of contact with the grinding wheel of each station, which in turn is arranged to remove material from the gemstone by rotating about axis Q - whereby each respective site 42, 44 may be arranged to linearly oscillate about and/or along axis Q. In addition, or alternatively, control of material removal process at bruting/cutting sites (such as 42, 44) may be performed by sensing (e.g. by sensor 403) proximity of the gemstone and/or engagement/contact of the gemstone (e.g. by Marposs sensor).

[049] Such sensing may also be via a laser or optic sensor. Possibly, bruting/machining process at such stations 42, 44 may be performed by altering machining RPM, such as by initially starting at a relative low RPM and once contact has been obtained – gradually increasing the RPM while possibly also gradually advancing the station along its axis B. Other means may be used for sensing such as acoustic & vibration sensors. 30

[050] Attention is drawn to Figs. 5A to 5E. After completion of a girdle and/or pavilion machining action(s) at bruting station 36 – the machined gemstone 24 may be advanced from holder 40 to head section 54 of the polishing station 48, possibly a first of a series of polishing stations – however in some cases only one polishing station may be provided. This first polishing station 48 of the machining station is generally marked by the dashed rectangle V in Fig. 1B.

[051] Fig. 5A illustrates a possible state after first gemstone handoff completion from a possible loaded-dop clamped in a dead-length collet block 402 to a head section 54 of the first polishing station 48, while Figs. 5B to 5E illustrate possible steps that may be taken to accomplish such handoff.

[052] The polishing station 48 here seen may be that illustrated e.g. in Figs. 5F to 5G (described in more detail below), however a first possible step for executing the transfer may include a linear servo-controlled movement of at least a portion of the polishing station 48, such as head section 54, towards a possible loaded-dop clamped in a dead-length collet block 402. This may be facilitated by provision of servo motor driving a lead screw connected to head section 54 along linear rails (see e.g. Fig. 5F), which are arranged to advance head section 58 along an axis Y possibly towards automatic gemstone centering and driving mechanism 40 to receive a machined gemstone from a loaded-dop. [053] Here the rails 77 are seen located above head section 54 however arrangements may be envisioned for supporting such linear movement along an axis parallel to Y e.g. from generally below head section 54. Polishing station head may be arranged to include a cushioned restraining damper e.g. 771 that may be arranged to dampen/restrain its dedicated seat 52 for seating the gemstone until reaches its final desired position.

[054] In the state seen in Fig. 5A, the gemstone 24 is seen located with portions of its pavilion abutting a dedicated seat 52 of the polishing station’s head section and clamped at that location, inter alia, by a clamp 50 of the polishing station head that presses the gemstone at its table against dedicated seat 52.

[055] The head section 54 of polishing station 48 may include fluid channels for activation of vacuum suction and/or pressurized air at a tip of dedicated seat 52 where the gemstone is adapted to be located. Activation and de-activation of such vacuum suction and/or pressurized air may be assisted by pressurized air arriving from pressurized air vessel source (not shown). Vacuum suction, possibly based on the V enturi effect, may be arranged to operate through a dedicated mechanism at the head section 54 for holding onto the gemstone being transferred.

[056] Prior to turning attention to Figs. 5B to 5E it is noted that the representation of the gemstone 24 illustrated in these figures is very schematic and does not accurately represent the gemstone's general outline - that may be more accurately depicted in Figs. 12 – where terminology typically used for naming several cuts in a gemstone are provided. Same applies to dedicated seat 52 that may be better viewed for its possible details in the representations provided in Figs. 13A to 13F to which attention is now drawn.

[057] In Figs. 13A and 13B a first possible embodiment of a dedicated seat such as 52 is illustrated – where in the enlarged section of Fig. 13B – such dedicated seat is shown possibly being formed with complementary facets 99 suitable for abutting and securing facets formed in a gemstone. A further dedicated seat embodiment illustrated in Figs. 13C to 13F illustrates possible formation of an undercut/recess (see enlarged section of Fig. 13E) that may be used for housing a seal 39 as illustrated in Fig. 13F. Such "seal" formation at a tip region of the dedicated seat may be useful in ensuring formation of vacuum suction at the tip region of the dedicated seat for securing a gemstone 24 at the tip.

[058] The dedicated seat visualized in Figs. 13C to 13F also embodies an optional cone like formation 97 at the tip area/region of the dedicated seat that is substantially devoid of any facets. Such formation may be useful in securing a gemstone that has not undergone yet facet formation at the area adapted to engage the tip region of the dedicated seat. A gemstone suitable for being secured at the dedicated seat of these figures – may have undergone only bruting prior to being secured to the dedicated seat. Combinations of a faceted tip region such as 99 with a 30 recess 33 and seal 39 may also be useful in certain embodiments e.g. as shown in Fig. 13G.

[059] Prior to discussing the hand-off procedure e.g., depicted in Figs. 5B onwards – attention is also drawn to Fig. 14 demonstrating closer views and embodiments of a clamp such as clamp 50. In this figure, the clamp is seen including a coupling region 93 for coupling the clamp to a machining/polishing station and an indentation 98 at its tip region distal to the coupling region that is adapted to abut against the gemstone. Both dedicated seat 52 and clamp 50 may be replacedchanged by a dedicated tool changer mechanism (not shown) so they will suitmatch the size and shapegeometry of the nextupcoming gemstone to be clamped by them. In the example seen in Fig. 14, a face 981 of indentation 98 may be formed tapering in a distal direction to generally follow a contour of a cone shape. Such a partial cone shaped indentation at the clamp's tip region – may represent an example suitable for abutting against a pavilion of a gemstone either after bruiting or after further faceting.

Indentation 98 may take form of other shapes suitable for abutting a gemstone's geometry (e.g. Oval, Hexagon, Square, etc.) to secure it to a dedicated seat. A tip region of a clamp not necessary requiring presence of such indentation may be of a clamp suitable for abutting against the table of a gemstone.

[060] Attention is now drawn to Fig. 5B, where the gemstone seen is still cemented and attached to a dop held clamped within bruting station 36. Fig. 5C represents a possible step where bruting station 36 and head section 54 of polishing station 48 are urged closer together – in the example illustrated optionally by urging head section 54 towards bruting station 36. The bruting and/or polishing stations may include dampers (e.g. 771) so that the meeting action between bruting station 36 and head section 54 occurring at the gemstone will be dampened to reduce possible damage to the gemstone and/or the machining utilities. [061] In the position seen in Fig. 5C, the gemstone is accordingly held cemented at its table to the dop that is clamped within bruting station 36, while portions of the gemstone’s pavilion are located at the tip of dedicated seat 52.

[062] With attention momentarily drawn back to Fig. 4A, bruting station 36 is seen also including a heating element 19, possible a gas burner. By rotating dead- length collet block 402 and/or moving heating element 19 – the gemstone in the position seen in Fig. 5C may be suitably placed in proximity to heating element 19.

Exposure of the gemstone vicinity to heat produced by heating element 19 may then burn off and/or dissolve the cement keeping gemstone 24 attached to the dop and consequently to bruting station 36. Activation and de-activation of such heat (possibly a flame) may be assisted by pressurized natural gas arriving from pressurized gas vessel source 14.

[063] Accordingly, vacuum suction applied at the bottom of dedicated seat 52 of polishing station 48 may be used to keep the gemstone safely attached at the dedicated seat in position and orientation until clamp 50 is urged to secure the gemstone at its table against the dedicated seat 52. This process may be applied by first distancing away head section 54 of polishing station 48 and its dedicated seat 52 now gripping onto the gemstone by vacuum suction (see Fig. 5D) and then securing the gemstone to dedicated seat 52 by clamp 50 (see Fig. 5E). After such instance the suction keeping the gemstone attached to the dedicated seat 52 may optionally be de-activated.

[064] Attention is drawn to Figs. 5F to 5H and 9A to 9C. Polishing station 48 as here seen also includes a polishing scaife/wheel section 56 located beneath the head section 54. Polishing scaife/wheel section 56 includes a polishing scaife/wheel 561, a linear servo-drive mechanism 57 and a guided 'Mass-Spring-Damper' (MSD) mechanism 58 (best seen in Fig. 9B providing an enlarged view of section IXb indicated in Fig. 5H). Machining actions occurring at polishing station 48 may include polishing/machining facets of the gemstone. Movements/transitions along and about several axes may be utilized in order to manipulate relative position between head section 54 and polishing scaife/wheel section 56 so that substantially many portions of the gemstone may be polished. Such polishing here includes biasing the polishing scaife/wheel -561 to move upwards and downwards by one or more guided 'Mass-Spring-Damper' (MSD) mechanisms 58 to meet the gemstone clamped possibly by head section 54. 30

[065] An example of a possible guided 'Mass-Spring-Damper' (MSD) mechanisms 58 is accordingly seen in the enlarged section provided in Fig. 9B. The guided MSD mechanisms 58 may include several main guide pillars 589, several main guide bushings 588, several secondary guide pillars 587, several secondary guide bushings 586, several stopper-columns 585, several top-frame plates 584, several mid-frame plates 583, several compression springs 582 (e.g. gas- spring/Bellevile springs/helical springs), several dampers 581 (e.g. viscous dampers/elastomer dampers), a polishing scaife/wheel-plate 580, several shear-pins 610 and a precise mechanical stopper 600 . Mechanical stopper 600 provided in polishing scife/wheel section 56 may be arranged to define an upper limit that the polishing scaife/wheel 561 can reach.

[066] Upward movement of the polishing scaife/wheel 561 towards the gemstone may include a slow incremental upward crawling of the polishing scaife/wheel 561 as optionally described below.

[067] Shear pin 610 may be urged to move upwards one incremental, pre- determined, distance by a possible linear servo-drive mechanism 57. Consequently, mid-frame 583 may be urged to move upwards, the same pre-determined distance, together with guided pillars 589, 587, stopper-column 585, dampers 581 and springs 582. The distance between the bottom of the mechanical stopper 600 and the top of the mid-frame plate 583 may be defined mainly by parameters of stopper-column 585 (e.g. its length) and mechanical stopper 600 (e.g. its thickness). As long as there is no external load on the polishing Scaife/wheel 561- the pre-loaded force of springs 5 holds in place polishing Scaife plate 580 against the mechanical stoppers 600 while maintaining springs 582 under a quasi-static load. Quasi-static load means a load applied substantially slowly so that the structure (springs 582 in our case) deforms also respectively slowly (generally at a substantially low strain rate) therefore resulting in an inertia force substantially small that can consequently be ignored.

Guide pillars 589 and 587, guided by guide bushings 588 and 586 respectively, maintain eventually the geometric relations between the polishing Scaife 561 and the gemstone 24. This way the machine may advance slowly its polishing Scaife 5 towards the gemstone 24.

[068] A gap may be opened between the mechanical stopper 600 and the polishing Scaife/wheel plate assembly 580 when polishing Scaife/wheel 561 touches a gemstone 24 since the gemstone thrust load/action on polishing Scaife/wheel 561 overcomes the springs pre-loaded force and thus creating a relative movement between itself and the rest of the members which keep moving upwards until they finish their pre-determined distance increment. This gap may be closed slowly since gemstone 24 is being polished by the polishing Scaife 561 and material is being removed both from the gemstone and the polishing Scaife 561. This relative movement between polishing scaife plate 580 and mid-frame plate 583 may be dampened by dampers 581. The presence of a Mass-damper-Spring mechanism elements enables to control and/or to optimize the response of the system to the incoming loads applied by gemstone 24 machining process.

[069] The position of stopper 600 may be chosen so that small incremental polishing actions may be performed. Each time a limit set by stopper 600 is reached, the precise mechanical stopper may be re-positioned slightly upwards to permit an additional incremental polishing action of the gemstone. The system may be arranged to detect when a limit set by stopper 600 is reached e.g. by the closing of an electric circuit confirming that plate 580 and stopper 600 are once again in contact. The polishing station may also include a probe 59 (e.g. Renishaw probe – see marked in Fig. 5F) for measuring and assisting in identifying if a target dimension of a machining, here polishing, action has been obtained/reached. The gemstone 24 may be moved during machining to the probe 59 and if determined may be moved back for further machining at polishing Scaife/wheel 561.

[070] Dedicated seat 52 extends along an axis G and is accordingly arranged to situate gemstone 24 at its free axial end. Dedicated seat 52 may also be rotated about axis G in relation to a body 62 of head section 54 and may include the procedure illustrated in Figs. 5I and 5J to which attention is now drawn.

[071] Once a planned machining action of the gemstone is complete, guided MSD mechanism 58 may retreat downwards and away from head section 54. If required, indexing of the gemstone about axis G may be then performed in order to place a new section of the gemstone facing downwards towards polishing Scaife/wheel 561. To permit such indexing, suction securing the gemstone to dedicated seat 52 may first be activated and then clamp 50 may be moved away from a position abutting the gemstone as illustrated in Fig. 5J.

[072] Attention is additionally drawn to Fig. 10 providing a cross sectional view generally similar to that in Fig. 5G (possibly a plane slightly rotated relative to the plane in Fig. 5G) revealing additional structure of head section 54. Dedicated seat 52 may be rotated about axis G together with a seat hub 510 by first releasing locking engagement of a peripheral brake pads 51 within body 62 by releasing hydraulic power of peripheral hydraulic pistons 55. Rotation of dedicated seat 52, while clamp 50 is detached from gemstone 24 and suction applied on gemstone 24, urges also gemstone 24 to rotate therewith. After completion of the required rotation, the locking engagement of the gripper within body 62 may be resumed and clamp 50 may return to the abutting position seen in Fig. 5I where it secures the gemstone against the dedicated seat 52.

[073] A subsequent polishing action of a new facet of the gemstone may then be performed by incrementally lifting the grinding wheel towards head section 54 as previously described. Facet formation in the gemstone at polishing station 48 may also include formation, inter alia, of break facets and/or other desired geometry of facets.

[074] Accordingly, several degrees of freedom (rotational and linear) within polishing station 48 may permit defining a variety of relative orientations between faces/sides of the gemstone and grinding section 56, in particular grinding wheel 561. These degrees of freedom may include tilt axis T permitting tilt of head section about an axis T, which in this example is seen extending generally parallel to the ground face. Such tilting of the head section may be in relation to a housing 53 that is here seen coupled to rotating table mechanism 88. Rotating table mechanism 88 30 may rotate housing 53 about axis P. After desired orientation of gemstone 24 relative to scaife/grinding wheel 561 may be achieved and after polishing direction of current facet was found (as described below), rotating table mechanism 88 may oscillate linearly (e.g. along the T Axis direction in our embodiment) or along a radial/parabolic curve profile - consequently oscillating housing 53 and head section 54, resulting in scaife/grinding wheel 561 to wear evenly.

[075] An additional rotational angle may permit defining different pan angles here of housing 53 (including head section that is secured to it) about an upright extending axis P. An additional rotational degree of freedom, already described above, may be that of seat 52 about axis G – while linear degrees of freedom/movements may be accordingly those along axis Y, along axis T and the up/down movement of the grinding section 56. [076] Diamonds typically have optimal polishing directions along which they can be polished most easily, which may sometimes be referred to as three crystallographic axesdirections of easy abrasion. In practice, such direction(s) is/are normally found by trial and error. In cases where the direction is known the trial and error process will be minimal. In embodiments discussed herein, trial an error of identifying such direction(s) along which polishing is adapted to take place – may be assisted by the above described degrees of freedom along and/or about e.g. axes P, G, Y and T.

[077] Detection of optimal polishing directions may be performed by use of 'means' for detecting when material commences to be removed by polishing off of the gemstone. Such 'means' may take form of an electric circuitsensor e.g. located within polishing scaife/wheel section 56 e.g. between stopper 600 and polishing scaife/wheel-plate 580. Successful removal by polishing of material from the gemstone - achieved when an optimal polishing direction is found - permits polishing scaife/wheel-plate 580 to rise upwards towards stopper 600 to be detected by said sensor e.g. closing an electric circuit confirming plate 580 and stopper 600 are once again in contact. Once proper orientation in relation to a polishing scaife/wheel 561- of a gemstone held within e.g. head section 54 has been obtained – the discussed 30 degrees of freedom permitting the finding of the optimal polishing direction may be "locked" and polishing action of the gemstone may take place to form e.g. a facet in the gemstone.

[078] Attention is drawn to Figs. 11A and 11B illustrating an embodiment of a dressing assembly 900 arranged for dressing an upper surface of polishing scaife/wheel 561. Such dressing may be performed when required without the need to dismantle wheel 561 from its position within the machining center. Dressing assembly 900 includes a dressing tool 901 and an actuator 902 arranged for linearly advancing and retreating the dressing tool along a direction DE that extends and coincides with a radial direction RE of wheel 561. In this example, in the upper view provided in Fig. 11A, dressing assembly 900 is shown at the left-hand side of wheel 561 – however said assembly 900 may be conveniently located about wheel 561 so that its axis DE coincides with the wheel's radial direction RW. With attention drawn to Fig. 11B it is seen that dressing assembly may be moved vertically in relation to a ground face along an axis V - to position dressing tool 901 at the appropriate height for dressing wheel 561.

[079] Attention is drawn to Figs. 5I to 5M and Fig. 6 illustrating possible handoff of the gemstone to a second polishing station 64 generally marked by the dashed rectangle indicated VI in Fig. 1B. Second polishing station 64 is generally similar to the first polishing station possibly with a difference in geometry of its dedicated seat, intended to seat a gemstone so that different facets of the gemstone may be formed such as e.g. pavilion facets, girdle facets, table facet and cult facet.

[080] Transfer of the gemstone from one polishing station 48 (delivering) to another polishing station 64 (receiving) may be performed as following.

[081] A first possible step for executing the transfer may include a linear servo- controlled movement of at least a portion of the delivering polishing station 48, such as head section 54, towards a possible receiving polishing station 64. This may be facilitated by provision of servo motor driving a lead screw connected to head section 54 along linear rails 77 (see e.g. Fig. 5F), which are arranged to advance head section 58 along an axis Y. 30

[082] Rails 77 are seen located above head section 54 however arrangements may be envisioned for supporting such linear movement along an axis parallel to Y e.g. from generally below head section 54. Polishing station head 54 may be arranged to include a cushioned restraining dampers until its dedicated seat 52 seating the gemstone reaches its final desired position, so that the meeting action between head sections of the two polishing stations 48, 64 occurring at the gemstone will be dampened to reduce possible damage to the gemstone and/or the machining utilities.

[083] Fig. 5J represents a possible step where vacuum suction applied at an axial rear side of dedicated seat 52 of polishing station 48 may be used to keep the gemstone safely attached at the dedicated seat 52 in position and orientation while clamps 50 of both head sections of the two polishing stations 48 & 64 may be removed.

[084] Fig. 5K represents a possible step where the head section of polishing station 48 and the head section of polishing station 64 are urged closer together – in the example illustrated optionally by urging the head section of polishing station towards of polishing station 64.

[085] After such contact vacuum suction applied at dedicated seat 521 of receiving polishing station 64 may be used to keep the gemstone safely attached at the dedicated seat 521 in a new position and orientation. After such instance the suction of the dedicated seat 52 of delivering polishing station 48 may be de-activated.

[086] In a subsequent possible step, distancing away of the head section of polishing station 48 may be activated while dedicated seat 521 may now be arranged for locating and seating the gemstone by vacuum suction (see Fig. 5L) and then securing of the gemstone to dedicated seat 521 may be activated by clamp 50 (see Fig. 5M).

[087] Polishing actions performed by the different polishing stations may be generally similar to those possibly performed and described with respect to the first polishing station as also illustrated in Figs. 5F to 5H, Figs. 9A to 9C and Fig. 10.

[088] Attention is drawn to Figs. 7A to 7D showing a final unloading and grading station 66 generally marked by the dashed rectangle indicated VII in Fig. 1B. 30 Gemstones exiting the machining area of the main machining cell 12 may be inspected for quality, packaged and finally stored.

[089] Station 66 may include a first manipulator 67, a gemstone grading machine 68, a second manipulator 69, a packaging element 63 and a packaging stand 65. In this example, first manipulator 67 may include a dedicated gripper mechanism including a dedicated seat 522 connected to a Mass-Spring-Damper (MSD) mechanism enabling a vacuum suction at the tip of dedicated seat 522, possibly in similarity to the descriptions already provided herein above. In this example, manipulator 69 may include a gripper in an optional form of an amorphous/adaptive gripper 691– here in form of a balloon filled with granular material that upon suction may be adapted to collapse and grip onto any amorphous object in contact therewith.

Gripper 67, here by being arranged to rotate inter-alia about an axis Z1, may be used for removing gemstones from the last polishing station and placing them at grading machine 68.

[090] After completion of grading of a gemstone, manipulator 69 with its amorphous gripper 691, here by being arranged to rotate inter-alia about an axis Z2, may be used for removing gemstones from the diamond grading machine 68 and placing them inside a receptacle (e.g. a Ziploc bag) waiting at packaging stand 65.

After such instance packaging element 63 may be used to seal the receptacle (e.g. attaching the Ziploc bag). Possibly, a stamp including properties of the gemstone may then be stamped to the receptacle and buffer station 70 may subsequently be used to temporarily store finished gemstones prior to them leaving the machining system for possible storage.

[091] In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.

[092] Furthermore, while the present application or technology has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non- 30 restrictive; the technology is thus not limited to the disclosed embodiments.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended claims.

[093] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage.

[094] The present technology is also understood to encompass the exact terms, features, numerical values or ranges etc., if in here such terms, features, numerical values or ranges etc. are referred to in connection with terms such as “about, ca., substantially, generally, at least” etc. In other words, “about 3” shall also comprise “3” or “substantially perpendicular” shall also comprise “perpendicular”. Any reference signs in the claims should not be considered as limiting the scope.

[095] Although the present embodiments have been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.

Claims (12)

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1. CLAIM S : 1. A gemstone machining center (10) comprising: a set-up station (18) adapted to deliver onwards loaded-dops each comprising a dop holder (22) and a gemstone (24) bonded to the dop holder, a bruting/cutting station (36) for receiving loaded-dops from the set-up station, and at least one polishing station (48), characterized in that the at least one polishing station being adapted for receiving gemstones after being detached from their dop holders by exposure of a vicinity of the gemstones to heat produced by a heating element (19) included in the bruiting/cutting station, the at least one polishing station comprising a dedicated seat (52) arranged for receiving a gemstone and for applying suction at the dedicated seat to at least temporarily hold onto the gemstone, and a clamp (50) being arranged to apply a clamping force to secure the gemstone against the dedicated seat after initially holding onto the gemstone by suction.
2. 2. The gemstone machining center of claim 1 and being of a transfer type comprising a combination of individual stations, arranged in sequence and connected by work transfer devices.
3. 3. The gemstone machining center of claim 1 or 2, wherein the set-up station comprising a loading section and a curing section, wherein possibly the loading section is arranged to receive capsules each comprising a gemstone cemented to its respective dop holder and the curing section being arranged to harden the cement attaching each gemstone to its dop holder to form loaded-dops.
4. 4 . The gemstone machining center of claim 4 and comprising a conveyer belt for carrying the dop holders with cemented gemstones through the curing section.
5. 5 . The gemstone machining center of claim 1, wherein the bruting/cutting station comprises an incoming hub for receiving loaded-dops from the set-up station, wherein possibly the bruting/cutting station comprises a holder center for clamping onto a loaded-dop and at least one bruting/cutting site for machining the gemstone of the loaded-dop. 30 - 25 -
6. 6 . The gemstone machining center of claim 5, wherein the holder center comprises a centering arrangement for centering a gemstone to be machined along an axis of rotation of the holder about which the gemstone is arranged to rotate during machining.
7. 7 . The gemstone machining center of any one of the preceding claims, wherein the bruting/cutting station is arranged to perform girdle and/or pavilion machining action(s) to the gemstone.
8. 8 . The gemstone machining center of claim 1, wherein transfer from the bruting/cutting station to the at least one polishing station comprises dissolving and/or removing the glue/cement holding a gemstone of a loaded-dop in its dop holder by the heat produced by the heating element (19).
9. 9 . The gemstone machining center of claim 8, wherein holding onto a gemstone after removing the glue/cement is by the suction applied at the dedicated seat.
10. 10. The gemstone machining center of any one of the preceding claims, wherein the clamp is applied during machining/bruting/polishing when suction is shut-down.
11. 11. A method for transferring a gemstone between machining/polishing stations (48, 64) comprising the steps of: providing a source machining/polishing station initially holding onto a gemstone, providing a destination machining/polishing station comprising a dedicated seat (52) arranged for receiving the gemstone and a clamp (50) for applying a clamping force against the gemstone to securely press it against the dedicated seat, urging at least one of the source and destination machining/polishing stations towards each other to bring the gemstone into contact with the dedicated seat, applying suction at the dedicated seat to at least temporarily hold onto the gemstone, and wherein the method further comprising - 26 - an indexing step of rotating the dedicated seat when already seating a gemstone to position a new region of the gemstone at a position suitable for machining/polishing, wherein the indexing step comprises: applying suction at the dedicated seat, retreating the clamp away from applying the clamping force against the gemstone and then rotating the dedicated seat, and possibly re-applying the clamping force by the clamp against the gemstone after rotation is completed.
12. 12. The method of claim 11, wherein suction initially holds onto the gemstone until the force by the clamp is applied against the gemstone, and possibly suction is terminated after clamping is applied. 1 3. The method of claims 11 or 12 and comprising a step of providing a tool changer for changing the type of dedicated seat and/or clamp at the destination machining/polishing station prior to receiving a gemstone, for example according to the geometry of gemstone being transferred to the destination machining/polishing center. 15