AU2006232003A1

AU2006232003A1 - Cut-off wheel

Info

Publication number: AU2006232003A1
Application number: AU2006232003A
Authority: AU
Inventors: Klaus Erles
Original assignee: Heger GmbH European Diamond Tools
Current assignee: Heger GmbH European Diamond Tools
Priority date: 2005-04-05
Filing date: 2006-03-22
Publication date: 2006-10-12
Anticipated expiration: 2026-03-22
Also published as: WO2006106391A8; EP1866127B1; AU2006232003B2; DE202005021802U1; ATE509733T1; CN101151125A; EP1866127A1; WO2006106391A1; CN100593458C; ES2366376T3; KR101279144B1; CA2603270A1; CA2603270C; KR20070120516A; DE102005015503A1

Abstract

The invention relates to an abrasive cutoff wheel which comprises a central disk (2) and a plurality of abrasive segments (4) which subtend between themselves a straight bonding line (10) that slants inward along a predetermined disk direction of rotation (12) toward the wheel center of rotation 14, deviating from a tangent line. Seen in wheel sideview, the radially outer surface (18) of each abrasive segment (4) preferably also is straight and slants inward along the wheel direction of rotation (12) toward the wheel center of rotation (14), deviating from a tangent line.

Description

WO 2006/106391 PCT/IB2006/000638 CUT-OFF WHEEL The present invention relates to an abrasive cutoff wheel defined in the pre amble of claim I to cut off building materials, in particular concrete, bricks, roof tiles, and to cut apart natural stone. A abrasive cutoff wheel of this kind is known form the German patent docu ment DE 44 24 093 C2. It comprises both a central disk and segments. The seg ments are undetachably affixed by laser welding to the central disk circumference which is continuous or which is sub-divided by circumferential clearances into pro jecting tabs. The line connecting the segments and the outer contour of the central disk runs tangentially to the central disk origin or is constituted by two corresponding tangential straight lines for each segment, said two lines subtending, in roof-like manner, between them an angle of less than 180". The objective of the present invention is abrasive cutoff-wheel improvement. This problem is solved by the features of claim 1 of the present invention. In the present invention, and as seen in wheel sideview, the disk junction face and the segment junction face affixed to it subtend a straight bonding line which, along a predetermined direction of wheel rotation, slopes inward toward the wheel center of rotation while deviating from a tangent line. The invention offers improved distribution of forces at the bonding line be tween the abrasive segments and the central disk, allowing higher loading on the abrasive cutoff wheel. The present invention converts a substantial portion of the shearing forces arising in the dry severing method into compressive forces that are applied in the bonding line between the abrasive segments and the central disk. Further features of the present invention are defined in the dependent claims. 1 WO 2006/106391 PCT/IB2006/000638 In one preferred embodiment mode of the present invention, the radially outer surface of each abrasive segment is straight when seen in wheel side view and this outer surface of each segment defines a surface line sloping inward in the direction of disk rotation toward the center of the wheel, deviating from a tangent line. As a result, when the abrasive cutoff wheel is used for the first time, only a minute part of each abrasive cutoff segment makes contact with the work piece to be cut, and thereby allows automatically honing the abrasive segments during first time use. The abrasive segments are composed of at least in their top zones of an imbedding material containing imbedded diamond elements illustratively sintered into said imbedding material. Before an abrasive cutoff wheel is used for the first time, the diamond elements do not protrude from the imbedding material, so that the abra sive cutoff wheel must be honed before or by means of first use to assure the dia mond elements shall project above the imbedding material. In another preferred embodiment mode of the present invention, the surface line and the bonding line of the particular abrasive segment are always mutually par allel. In a further preferred embodiment mode of the present invention, the central disk is fitted with one circumferential notch between all adjoining disk junction faces. In this manner material abraded from a workpiece more easily escapes from the notch formed in the workpiece. The present invention is elucidated below by means of a preferred embodi ment and in relation to the appended drawing. Fig. 1 is a sector-like cutaway of a sideview of an abrasive cutoff wheel of the invention. 2 WO 2006/106391 PCT/IB2006/000638 The abrasive cutoff wheel of the invention shown in Fig. 1 substantially com prises a circular central disk 2 and a plurality of abrasive segments 4. The abrasive segments 4 are distributed preferably symmetrically along the full outer circumfer ence of the central disk 2 on the same plurality of straight (as seen in wheel side view) disk junction faces 6 and each segment is fitted with its own segment junction face 8 that is undetachably joined, for instance by brazing, welding or laser proc essing, to one of the disk junction faces 6. The central disk 2 preferably is made of steel. The abrasive cutoff wheel of the invention does its cutoff work in a predeter mined direction of rotation 12. Each disk junction face 6 and the segment junction face 8 joined to it deter mine between them a straight bonding line 10 (as seen in wheel sideview), this bonding line sloping inward along the predetermined direction of wheel rotation 12, relative to wheel center of rotation 14, that is, deviating from a line tangent to the wheel center of rotation. A conceptual radial line from the wheel center of rotation 14 to the center (in sideview) of a disk junction face 6 subtends an angle with said surface 6 that deviates from 900. The radially outer surface 18 of each abrasive segment 4 is straight when seen in wheel sideview and defines a straight surface line 20 which as seen in wheel sideview slants in the direction of rotation of the wheel toward the wheel cen ter of rotation 14, deviating from a tangent line. The surface line 20 and the bonding line 10 of the particular abrasive segment 4 preferably are mutually parallel. Between every two mutually adjacent disk junction faces 6, the central disk 2 is fitted with a circumferential notch 22 respectively 24. 3 WO 2006/106391 PCT/IB2006/000638 In the preferred embodiment mode shown in Fig. 1, the circumferential notches 22 and 24 differ in depth, a deeper circumferential notch 24 and a shallower circumferential notch 22 alternating along the circumference. The configuration of circumferential notches of different depths lowers the danger of cracks in the central disk. A spacer gap 26 is subtended in all embodiment modes of the invention be tween the circumferentially sequential abrasive segments 4 to facilitate eliminating ground material when grinding the workpiece. The bonding line 10 and a radial line 30 subtend an angle deviating from 90 at least at the longitudinal center point of the disk junction face 6, preferably however also at any other point along the length of the segment junction face 8. As a result the angle a situated in the predetermined wheel direction of rotation 12 in front of the radial line 30 is less than 90" and the angle 3 situated behind is larger than 90*. The circumferential notches 22 and 24 preferably are slots open at the outer central disk circumference. Said notches subtend a defined angle y preferably larger than 90" with the connecting line 10, respectively the disk junction surface 6, pre ceding them in the wheel's direction of rotation 12. 4

Claims

1. An abrasive cutoff wheel comprising a central disk (2) and a plurality of abrasive segments (4) distributed along the circumference of the central disk (2) on the same number of disk junction faces (6) that are straight as seen in wheel side view and that comprise each a segment junction face (8) which is undetachably af fixed to only one of the disk junction faces (6), characterized in that the abrasive cutoff wheel is driven into a predetermined direction of rotation (12), in that each disk junction face (6) and the segment junction face (8) affixed to it when seen in wheel sideview subtend a straight bonding line (10) which, in the pre determined direction of rotation (12) slopes inward toward the wheel center of rota tion (14), deviating from a tangent line.

2. Abrasive cutoff wheel as claimed in claim 1, characterized in that the radially outer surface (18) of each abrasive segment (4) is straight as seen in wheel sideview and defines a straight surface line (20) which slants inward in the direction of the wheel center of rotation (14), deviating from a tangent line.

3. Abrasive cutoff wheel as claimed in claim 2, characterized in that the surface line (20) and the bonding line (10) of the particular abrasive segment (4) are mutually parallel.

4. Abrasive cutoff wheel as claimed in one of the above claims, charac terized in that the central disk (2) comprises a circumferential notch (22, 24) at every two adjacent disk junction faces (6). 5 WO 2006/106391 PCT/IB2006/000638

5. Abrasive cutoff wheel as claimed in claim 4, characterized in that the depths of the circumferential notches (22, 24) are different, a deeper circumferential notch (24) and a shallower circumferential notch (22) alternating in the wheel circum ferential direction.