MACHINING TOOL

Abstract: When machining timber products such as planks and chipboards, tools are used which perform the machining at their periphery. The machining capacity is reduced with use and the tool must therefore be ground after a certain period. The object of the invention is to simplify grinding and this is achieved by using a divided saw blade (7) which during grinding is flat and during machining has meeting ends at slits (13, 14, respectively) spaced axially from each other.

Description: Machining tool The present invention relates to a machining tool which peripherally machines a material upon rotation. The present application is primarily the machining of timber products to remove parts of the material by disintegration. Suchdisintegrationmaybecarriedoutinamillingprocess, for instance, grooves being milled or surface layers removed. Machining tools other than millers are also feasible. The tool is subjected to wear during use and it must therefore be ground at regular intervals. Grinding is generally time-consuming and expensive. The object of the present invention is to simplify the grinding process for a machining tool and thus reduce costs for sharpening said tool. This is enabled according to the present invention by using a conventional saw blade which is slit to give two or more circumferential portions, meeting parts at a slit being axially displaced. The displacement at each slit can be maintained with the aid of a single body with portions extending from a centre coinciding with the centre of the saw blade. Each portion is provided at its periphery with two flat surfaces, parallel to each other and perpendicular to the axis of the saw blade. The ends at a slit abut these surfaces. Abutment may be such that adjacent parts of the saw blade are completely parallel with a cooperating surface. A machining too according to the invention may be provided on one side with a cutting saw blade. Furthermore, two or more machining tools may be placed adjacent each other and such a package can, if desired, be provided in the manner described above with a cutting saw blade on one or both sides. Additional characteristics of the present invention are revealed in the following claims. The present invention will be more fully described with reference to the accompanying two sheets of drawings in which Figures 1 and 2 show one and the same machining tool in two positions, one o position being turned 90 with respect to the other position, 5 Figure 3 shows the machining tool according to Fig.1 seen from the side, and Figure 4 shows the machining tool according to Fig.2 seen from the • side. In the drawings 1 is a flat saw blade with teeth 2, each provided with a 1 hard-metal layer or hard-metal cutting edge. The saw blade 1 is provided with an intermediate ring 3« On the intermediate 3 is a second saw blade 7» provided with teeth 8 having a hard-metal coating or hard-metal cutting edge. The saw blade 7 is provided with two recesses 9 and 10 so that, along most of its periphery it has the form of a ring or band. Due to said 15 recesses the saw blade acquires a transverse portion 11 which per se includes a diameter of the saw blade. Two slits are arranged close to the ends of the part 11. Two halves of a ring, designated 15 and 16, are obtained due to said slits. The ends by the slits 13 and 14 a parted in axial direction. Between the parted ends is inserted a body 4 having two 20 flat surfaces 5 and 6 parallel to each other. Parted ends abut against the flat surfaces in the ends of the body 4 as shown in the drawings. Thus, according to Figure 1, the upper end part of the ring-half 16 abuts the flat surface 5 of the body 4 while the upper end of the ring-half 15 abuts the flat surface 6 of the body 4. The lower end of the ring-half 16 25 according to Figure 1 abuts the flat surface 6 of the body 4 and the lower end of the ring-half 15 abuts the flat surface 5 of the body 4. Adjacent ends are substantially parallel to the abutting surfaces and firmly con¬ nected to the body 4 by screw joints. The saw blade 7 has a central aperture 12 and the body 4 is also provided with a corresponding central 30. aperture. There are fewer teeth on the saw blade 7 than on the saw blade 1. The machining tool described above is intended for use in sawing off the * outer edge of a slab of wood or chipboard, the width of the sawn-off edge r, being less than the distance between two ends of two ring-halves 15 and 16. The machining tool shown in the drawings is placed on a shaft and the saw 5 blade 1 is then located nearest the surface which shall remain when the edge is sawn off. The saw blade 7 is located at the edge. If the shaft on which the machining tool according to the drawings is placed is now moved towards the slab to be. cut clean, the saw blade 1 will effect the actual cutting and the blade 7 will destroy the edge formed outside said cut. It is 10 therefore an advantage if the number of teeth is greater on the part carrying out the actual cutting. The procedure described here gives the advantage that material sawn off is pulverized instead of remaining in the form of a strip or the like. This facilitates the removal of excess material. Furthermore, it is obtained in a form suitable for use a fuel. 15 If material . of considerable width is to be destroyed, two or more saw blades 7 may be arranged one after the other with a body 4. A package of saw blades is thus obtained for the desctruction of material, the quantity of material destroyed being dependent on the size of the blade package. According to the invention, thus a package consisting only of a number of 20 bodies 4 with saw blades 7. Such packages can also be provided with flat saw blades 1 at either one or both ends. A means according to the invention is useful not only for removing edges from panels but also for producing grooves or recesses in timber products, such as poles, posts and the like. <? OMPI

Claims: CLAIMS 1. Machining tool, machining being effected at the periphery upon rotation of the tool, characterised in that the tool consists of a circular saw blade (7) having teeth (8) at its periphery with or without a hard-metal layer and being divided by two or more substan- tially radial sections (13 and 14) into two or more consecutively arranged arc-shaped circumferential portions (15 and" 16), and that meeting ends at a section (13 or 14, respectively) between two con¬ secutive circumferential portions (15 and 16) are axially displaced in relation to each other. 2. Machining tool according to claim 1, characterised in that the dis¬ placement at each section (13» 14, respectively) is maintained by a spacer (11 . 3. Machining tool according to claim 1, characterised in that the teeth (8) near a section (13> 14, respectively) are located in planes perpendicular to the axis of the saw blade (7). 4. Machining tool according to claim 2, characterised in that all spacers (11 are formed by a body having a centre common to the centre of the saw blade (7) and with peripheral parts in the form of spacers (11). 5- Machining tool according to one or more of the preceding claims, characterised in that every spacer (11) has two external surfaces parallel to each other and perpendicular to an axis through the centre of the saw blade (7)• 6. Machining tool according to one or more of the preceding claims, characterised in that the arc-shaped circumferential portions (15 and 16) are in the form of part of a band or ring. 7. Machining tool according to one or more of the preceding claims, characterised in that a flat, unslit saw blade (1) is arranged out¬ side the slit saw blad (7). 8. Machining tool according to claim 7, characterised in that two or more slit saw blades (7) are located beside each other and that outside said slit saw blades (7)j on one or both sides thereof a flat, unslit sau blade (1) is arranged.

Inventors: KARLSSON BERTIL, KARLSSON, BERTIL
Applicants: ARHO MEKAN, ARHO-MEKAN
Application year: 1982
Main classification: B27G13
IPC codes: B27B33