1. a sawing yarn comprising an abrasive mixture containing a bonding resin and abrasive material, and a multifilament of fibers which have high tensile strength and are preferably arranged substantially parallel to one another and are surrounded by the abrasive mixture, the space between the fibers being filled with the abrasive mixture, characterized in that the bonding resin contains no polytetrafluoroethylene:
2. A sawing yarn comprising an abrasive mixture containing a bonding resin and abrasive material, and a multifilament of fibers which have high tensile strength and are preferably arranged substantially parallel to one another and are surrounded by the abrasive mixture, the space between the fibers being filled with the abrasive mixture, characterized in that the amount of abrasive material in the abrasive mixture decreases gradually from the surface of the abrasive yarn to the interior.
3. The sawing yarn as claimed in claim 1, the sawing yarn having a thickness equal to or less than 350 m.
4. The sawing yarn as claimed in claim 1, the sawing yarn having a thickness of 125-300 m.
5. The sawing yarn as claimed in claim 1, the fibers being composed of a material from the group consisting of m- andor p-aramid, ultra-high-strength polyethylene, highly oriented polyester, polyester, polyamide, carbon fibers, p-polyphenylene-2,6-benzobisoxazole or glass fibers, and combinations thereof.
6. The sawing yarn as claimed in claim 5, the fibers being composed of m-aramid, p-aramid or ultra-high-strength polyethylene.
7. The sawing yarn as claimed in claim 5, the fibers being composed of p-polyphenylene-2,6-benzobisoxazole.
8. The sawing yarn as claimed claim 1, the bonding resin being composed of a thermoplastic or thermosetting polymer or a combination of these materials.
9. The sawing yarn as claimed in claim 8, the bonding resin being composed of a thermosetting polymer.
10. The sawing yarn as claimed in claim 9, the thermosetting polymer being selected from the group consisting of curable phenol resins, epoxy resins, curable phenolformaldehyde resins, MF molding materials and curable melaminephenolformaldehyde (MPF) molding materials, and combinations thereof.
11. The sawing yarn as claimed in claim 8, the bonding resin being composed of a thermoplastic polymer selected from the group consisting of polyimides, polyamides and polyether ether ketones.
12. The sawing yarn as claimed in claim 1, the abrasive material being selected from the group consisting of finely classified diamond, silicon carbide (SiC), Al2O3, cubic boron nitride (c-BN), TiC, ZrC, HfC, mixtures of these carbides, TiN, ZrN, HfN or mixtures of these nitrides, and combinations thereof.
13. The sawing yarn as claimed in claim 12, the abrasive material being finely classified diamond.
14. A method for the production of a sawing yarn as claimed in claim 1, comprising the steps
a) preparation of a multifilament of fibers having high tensile strength,
b) coating or filling of this multifilament with an abrasive mixture comprising a bonding resin and abrasive material, and
c) further processing of the multifilament thus obtained.
15. The method as claimed in claim 14, the coating or filling in step b) being effected by a wet impregnation method or a dry coating method.
16. The method as claimed in claim 15, step b) being carried out by a dry coating method by drawing the multifilament through a fluidized bed.
17. The method as claimed in claim 16, step b) being carried out in a two-stage process, first by drawing the multifilament through a fluidized bed containing bonding resin and a small amount of abrasive particles or no abrasive particles and, after subsequent sizing, again by drawing through a fluidized bed containing abrasive particles and a small amount of bonding resin or no bonding resin.
18. The method as claimed in claim 16, step b) being carried out in a twin fluid bath, comprising passing the multifilament through a first tank, containing bonding resin, and transferring the multifilament to a second tank, containing abrasive material and a small amount of bonding resin.
19. The method as claimed in claim 18, the multifilament being removed vertically from the first tank, twisted, deflected, at least partly opened and then fed into the second tank.
20. A sawing yarn produced by the method of claim 14.
21. The sawing yarn as claimed in claim 20, characterized in that the amount of abrasive particle in the abrasive material decreases from the outside to the inside.
22. The use of a sawing yarn as claimed in claim 1 for cutting hard brittle materials.
23. The use as claimed in claim 22, the hard brittle material being selected from the group consisting of single silicon crystals, silicon carbide, sapphire, quartz, emerald, ruby, ceramic and Al2O3.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A joint engagement device comprising:
a base board having a plurality of first joints defined therein and two sidewalls extending from said base board, a connection board connected between said two sidewalls and two slots defined through said connection board;
a carrier member having a transverse bar and two posts extending from two ends of said transverse bar, said two posts movably extending through said two slots in said connection board, each of said two posts having two notches defined in a surface thereof and each of said two posts having a groove defined longitudinally in an inside thereof, said notches communicating with said groove in each of said posts;
an operation frame having a handle and two arms extending from two ends of said handle, said two arms respectively and pivotally connected to two respective insides of said two sidewalls by two first bolts, said two arms respectively connected to said two posts by two second bolts, and
an engaging board having a plurality of second joints and two protrusions extending from each one of two sides of said engaging board, said protrusions being inserted into said notches and slidably received in said grooves, said operation frame being moved toward said base board to engage said second joints with said first joints when pivoting said operation frame toward said base board.
2. The device as claimed in claim 1 further comprising two limits extend from said base board and located above said first joints.
3. The device as claimed in claim 1 further comprising a seal pad connected to said engaging board and said second joints extending through said seal pad, said seal pad matching with said base board when said first joints engaged with said second joints.
4. The device as claimed in claim 1 wherein said first bolts are located lower than said second bolts when said operation frame is not pivoted toward said base board, said first bolts being located higher than said second bolts when said operation frame is pivoted toward said base board.
5. The device as claimed in claim 1 further comprising two links respectively connected between said two posts and said two insides of said two sidewalls, a first end of each of said links pivotally connected to said inside of said sidewall and a second end of each of said links connected to said post.