GB2056335A - Sawing gemstones - Google Patents

Sawing gemstones Download PDF

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Publication number
GB2056335A
GB2056335A GB8025942A GB8025942A GB2056335A GB 2056335 A GB2056335 A GB 2056335A GB 8025942 A GB8025942 A GB 8025942A GB 8025942 A GB8025942 A GB 8025942A GB 2056335 A GB2056335 A GB 2056335A
Authority
GB
United Kingdom
Prior art keywords
band
gemstones
blade
saw
members
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8025942A
Other versions
GB2056335B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gersan Ets
Original Assignee
Gersan Ets
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gersan Ets filed Critical Gersan Ets
Priority to GB8025942A priority Critical patent/GB2056335B/en
Publication of GB2056335A publication Critical patent/GB2056335A/en
Application granted granted Critical
Publication of GB2056335B publication Critical patent/GB2056335B/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D99/00—Subject matter not provided for in other groups of this subclass
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D59/00—Accessories specially designed for sawing machines or sawing devices
    • B23D59/001—Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade
    • B23D59/002—Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade for the position of the saw blade
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D63/00—Dressing the tools of sawing machines or sawing devices for use in cutting any kind of material, e.g. in the manufacture of sawing tools
    • B23D63/005—Workpiece indexing equipment specially adapted to form part of sawing tool dressing machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D65/00—Making tools for sawing machines or sawing devices for use in cutting any kind of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D1/00—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
    • B28D1/02—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by sawing
    • B28D1/12—Saw-blades or saw-discs specially adapted for working stone
    • B28D1/127—Straight, i.e. flat, saw blades; strap saw blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/0058—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/04—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by tools other than rotary type, e.g. reciprocating tools
    • B28D5/045—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by tools other than rotary type, e.g. reciprocating tools by cutting with wires or closed-loop blades

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Mining & Mineral Resources (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)

Abstract

A band-saw is used to saw gemstones, e.g. diamonds in two. The saw blade (10) of the band-saw is a band the width of which is at least three times its thickness. The gemstones may be carried by a plurality of holders 25 so as to be fed into both edges of the blade. The blade may be mounted on spaced rollers and a device provided for sensing the position of the blade on the rollers, means responsive to the sensing device being activated to prevent movement of the blade radially of the rollers. <IMAGE>

Description

SPECIFICATION Sawing gemstones This invention relates to a method of and apparatus for sawing gemstones, e.g. diamonds, in two.
Although in the following specification reference will be made, for simplicity, to sawing of diamonds, it is to be understood that the invention also may be applied to the sawing of other gemstones.
It has been common practice to use discshaped saw blades for sawing diamonds in two.
The main disadvantage of this type of blade is that it has been necessary to use a blade having a thickness of 50 microns or more to avoid buckling when sawing stones of say 1/4 Ct.
In a first aspect, the invention provides a method of sawing gemstones in two, comprising: employing a bandsaw wherein the saw blade of the bandsaw is a band the width of which is at least three times its thickness.
Further preferred or optional features of the method according to the first aspect of the invention, are set in claims 2 to 6 appended hereto.
In a second aspect, the invention provides apparatus for performing the method according to the first aspect, the apparatus comprising a bandsaw wherein the saw blade of the band saw is a band the width of which is at least three times its thickness, and means for feeding a plurality of gemstones into engagement with at least one edge of the saw blade.
Further preferred or optional features of the apparatus according to the second aspect of the invention are set forth in claims 8 to 22 appended hereto.
The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein: - Figures 1 to 4 show various different arrangements for stabilizing the blade of a band saw against a twist during a sawing operation according to the method of the invention.
Figure 5 shows an arrangement for supporting gemstones during a sawing operation according to the method of the invention, and Figure 6 shows an arrangement-for supporting the blade of a band saw during a sawing operation according to the method of the invention.
Instead of sawing diamonds in two with conventional disc-shaped saw blades a band saw is used. As in the case of conventional disc-shaped saw blades the blade of the band saw is formed from a copper based alloy or from an iron based alloy and the cutting edge or edges of the band have powdered diamond applied thereto. The use of the band saw permits a plurality of diamonds to be sawn simultaneously and, whereas, when sawing stones of say 1/4 Ct, conventional discshaped saw blades need to have a thickness of 50 microns or more to avoid buckling, a blade of a band saw may have a thickness of 20 microns or less. The width of the band of the band saw should be at least three times its thickness and preferably as much as one hundred or even one thousand times its thickness.
A plurality of diamonds may be cut in two simultaneously by a single band of a band saw.
The diamonds may be fed into engagement with one or both edges of the band.
During sawing, the band saw is driven at a high velocity, e.g. 50 metres per second or more and at this speed the band will have to be guided, particularly if diamonds are fed into engagement with only one edge of the band, since otherwise the band will move axially along the roller peripheries.
It is believed that the use of rollers having curved peripheries will assist in locating a band against axial movement on the rollers.
However, it is thought that the most effective way of locating the band against axial movement on the rollers at such high velocities will be to feed diamonds into engagement with both edges of the band.
It may also be important to stabilize the band against twist. Various different arrangements for stabilizing the band against twist are shown in Figures 1 to 4. Figure 1 shows rollers 11, which may be supported in fluid bearings, engaging opposed surfaces of the band denoted by reference numeral 10 and spaced from a single cutting edge 12 (the upper edge as shown) of the band 10. Figure 2 shows rollers 11' engaging opposed surfaces of the band 10 and spaced from twin cutting edges 12' of the band 10. Figure 3 shows rollers 11N engaging opposed surfaces of the band 10 and extending between the upper and lower edges thereof. Although, a better result is expected from this arrangement as compared with, that shown in Figure 1 or 2, contact is made with the cutting edge(s) of the band.Thus, the arrangement shown in Figure 4 is expected to give the best results. In this arrangement the blade is guided by one or more contactless slider bearings- 13 which may be of any suitable type, such as hydrodynamic or hydrostatic oil or air bearings, or inductive or capacitive bearings.
Figure 5 shows a diamond feeding device for supporting and feeding a plurality of diamonds into engagement with opposite edge of the band.
The device, indicated generally by the reference numeral 20, comprises a table 21 which is supported so as to be freely movable to a small degree in a direction perpendicular to the direction of travel of the band. The table 21 is of generally U-shaped cross-section having two parallel limbs 22 and 23 lying adjacent to opposite edges of the band and each carrying a plurality (as shown four) of independently movable feed members 24, each of which carries a diamond supporting member 25.
Another embodiment of apparatus for cutting gemstones in two, is shown in Figure 6 and may be used in conjunction with the device of Figure 5 and/or one or more of the arrangements shown in Figures 1-4. The apparatus shown in Figure 6 includes two spaced rollers 30 and 31. The roller 30 is journalled for rotation about a fixed axis 32.
The roller 31 is supported in a cradle 33 for rotation about an axis 34. The cradle 33 is mounted for angular movement about an axis 35 preferably coincident with a rectilinear line tangential to the circumference of both rollers 30 and 31 and joining circumferentially corresponding positions on these two rollers 30 and 31. However, satisfactory results may also be obtained if the axis 35 is disposed further away from the roller axes 12 and 14 i.e. spaced outwardly from the blade.
A band 10' has opposite edges 37 and 37' and is positioned over the two rollers, which as viewed in Figure 6, rotate in an anti-clockwise direction.
The portion of the edge 37 extending between the rollers 30 and 31 and lying immediately upstream of roller 31 is arranged to be coincident with the axis 35. A position sensing device 38 is fixed in space and mounted so as to sense the position of the edge 37 along a portion downstream of roller 31 and preferably immediately downstream of roller 31. The position sensing device 38 may be of an electronic or pneumatic type and is connected to a servo amplifier 39 which operates an actuator 40 for angularly displacing the cradle 33 about its axis 35.
The rollers 30 and 31 may be movable away from each other, so as to stress the band 16, by a force actuator 41 controlled by a metering device 42.
The purpose of the position sensing device 38, the servo amplifier 39 and the actuator 40 is to move the cradle 33 angularly in a sense which will correct against any slight axial movement of the band along the surface of the roller 10'.
As shown in Figure 6, the position sensor 38 is located on the downstream side of the roller 31 relative to the direction of movement of the band around this latter roller.
In an alternative embodiment, and as shown by broken lines in Figure 6, a position sensing device 38' can be fixed relative to the cradle 33. In this case, the rollers 30 and 31 are rotated in a clockwise direction with the device 38' arranged on the upstream side of the member 31 relative to the direction of movement of the band around this latter roller.
The rollers 30 and 31 may have a flat or a curved surface.
Diamond powder is applied in a conventional manner to one or both edges of the band 10' and diamonds may be fed into engagement with one or both edges of the band.
Preferably, the band of the band saw described in all of the preceding embodiments comprises a seamless band which can be manufactured in the manner described in our copending Application No. (M s C Folio ). However, it is within the scope of the invention to provide a band formed from a strip of material, the ends of which are welded together to form a transverse or spiral seam.

Claims (25)

1. A method of sawing gemstones in two, comprising: employing a band-saw wherein the saw blade of the band saw is a band the width of which is at least three times its thickness.
2. A method as claimed in claim 1, wherein the blade is a seamless band.
3. A method as claimed in claim 1 or claim 2, wherein the saw blade is driven at a speed of at least 25 meters per second.
4. A method as claimed in any ono of claims 1 to 3, wherein a plurality of gemstones are sawn simultaneously by a single blade.
5. A method as claimed in claim 4, wherein gemstones are sawn simultaneously by opposite edges of the blade.
6. A method as claimed in claim 4 or claim 5, wherein each of said plurality of gemstones is individually fed into engagement with an edge of the blade.
7. Apparatus for performing the method claimed in any one of claims 1 to 6, the apparatus comprising a band-saw wherein the saw blade of the band-saw is a band the width of which is at least three times its thickness, and means for feeding a plurality of gemstones into engagement with at least one edge of the saw blade.
8. Apparatus as claimed in claim 7, wherein the band is a seamless band.
9. Apparatus as claimed in claim 7 or claim 8, wherein the feeding means is arranged so as to feed gemstones into engagement with opposite edges of the band.
10. Apparatus as claimed in claim 7 or claim 8, wherein the feeding means is arranged so as to feed gemstones into engagement with one edge only of the band.
11. Apparatus as claimed in any one of claims 7 to 10, wherein guide means are provided for stabilising the blade against twist.
12. Apparatus as claimed in claim 11, wherein the guide means comprises rotatable members.
13. Apparatus as claimed in claim 12, wherein the rotatable members are supported in air bearings.
14. Apparatus as claimed in claim 11, wherein the guide means comprises one or more contactless slider bearings.
1 5. Apparatus as claimed in any one of claim 7 to 14, wherein the feeding means comprises a table, which is supported for movement transversely to the band, the table having mounted thereon a plurality of independently movable feed members for supporting the gemstones and for feeding the latter into engagement with the band.
16. Apparatus as claimed in any one of claims 7 to 15 further comprising first and second spaced rotatable members, first means for sensing the position of a band disposed in use over the members, and second means responsive to the first means for preventing or substantially preventing the band from moving axially along the circumference of at least one of the rotatable members.
17. Apparatus as claimed in claim 16, wherein said second means comprises a cradle which supports the first member for rotation and which is angularly movable in response to said first means about an axis normal to the plane of movement of the axis of the first member such that, in use during rotation of the members, the band is prevented or substantially prevented from moving axially along the circumference of the second member.
18. Apparatus as claimed in claim 17, wherein the axis about which the cradle is angularly movable is coincident with a rectilinear line joining circumferentially corresponding positions on the two members.
19. Apparatus as claimed in claim 17 or claim 18, wherein the position sensing means is fixed in space relative to the axis of the second member so as, in use, to sense the position of the band intermediate the first and second members on the downstream side of said first member relative to the direction of movement of the band around said first member.
20. Apparatus as claimed in claim 17 or claim 18, wherein the position sensing means is fixed relative to the cradle so as, in use, to sense the position of the band intermediate the first and second members on the upstream side of said first member relative to the direction of movement of the band around said first member.
21. Apparatus as claimed in any one of claims 15 to 20, wherein the position sensing means is pneumatic.
22. Apparatus as claimed in any one of claims 15 to 20, wherein the position sensing means is electronic.
23. A method of sawing gemstones substantially as hereinbefore described.
24. Apparatus for sawing gemstones, substantially according to any one of the embodiments hereinbefore described with reference to and as shown in the accompanying drawings.
25. A gemstone sawn in two according to the method claimed in any one of claims 1 to 6 and 23.
GB8025942A 1979-08-13 1980-08-08 Sawing gemstones Expired GB2056335B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8025942A GB2056335B (en) 1979-08-13 1980-08-08 Sawing gemstones

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB7928166 1979-08-13
GB8025942A GB2056335B (en) 1979-08-13 1980-08-08 Sawing gemstones

Publications (2)

Publication Number Publication Date
GB2056335A true GB2056335A (en) 1981-03-18
GB2056335B GB2056335B (en) 1982-11-24

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8025942A Expired GB2056335B (en) 1979-08-13 1980-08-08 Sawing gemstones

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GB (1) GB2056335B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0799680A2 (en) * 1996-04-01 1997-10-08 Saint-Gobain/Norton Industrial Ceramics Corporation Method and apparatus for cutting diamond

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0799680A2 (en) * 1996-04-01 1997-10-08 Saint-Gobain/Norton Industrial Ceramics Corporation Method and apparatus for cutting diamond
EP0799680A3 (en) * 1996-04-01 1998-04-01 Saint-Gobain/Norton Industrial Ceramics Corporation Method and apparatus for cutting diamond

Also Published As

Publication number Publication date
GB2056335B (en) 1982-11-24

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Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19930808