Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
  • B23Q11/0032—Arrangements for preventing or isolating vibrations in parts of the machine
  • B23Q11/0039—Arrangements for preventing or isolating vibrations in parts of the machine by changing the natural frequency of the system or by continuously changing the frequency of the force which causes the vibration
• • 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
  • B23D61/00—Tools for sawing machines or sawing devices; Clamping devices for these tools
  • B23D61/02—Circular saw blades
  • B23D61/021—Types of set; Variable teeth, e.g. variable in height or gullet depth; Varying pitch; Details of gullet

Definitions

• the present invention relates to a cutting machine tool which is provided with a number of cutting edges.
• the object of the present invention is to produce a cutting tool constructed so that compared to known tools of the same kind it causes lower noise nuisances. It should also be possible to obtain this reduction of the noise nuisances even if the noise of the tool has been suppressed in some other way, e.g. by lamination or slitting.
• the distance between the separate cutting edges of an ordinary cutting machine tool is constant, and so the cutting edges will engage consecutively at one engagement frequency when the tool is moved at a constant speed. Such a tool will cause a noise which by and large is concentrated on the engagement frequency and multiples thereof.
• any sequence consisting of random binary numerals may be used as a basis for the tool according to the invention, in which sequence the order of binaries "1" and "0" is statistically random, but the statistic extremes of e.g. a sequence consisting exclusively of "0" or "1" are, however, of no practical interest, just as very short sequences with few such as 2-3 numerals or consisting of such a short series of numerals repeated several times, must be regarded as useless.
• the cutting edges are placed as stated in claim 2. The advantage of uniform sections being obtained in this way is that the cutting edges may be sharpened on ordinary automatic grinding machines. Furthermore, the tool according to the invention may thus be made easily from an ordinary tool where all the cutting edges have the said minimum distance and where the cutting edges corresponding to "0" are simply removed, of claims 9 and 10.
• sequences should be used which include many and at any rate no less than four numerals.
• PRBS Physical Broadcasting Binary Signal
• the noise nuisances of the working tool may be reduced further by the embodiment stated in claim 8. If it appears, for example, that the engagement frequency corresponding to the sequence section lies in the most sensitive hearing range, some of the cutting edges may be removed whose distance to the following cutting edge is the section, or they may be placed in areas with a larger distance between the cutting edges. It is, however, most expedient, already at production ⁇ f the random sequence, to ensure a smaller frequency of e.g. closely arranged cutting edges and a correspondingly larger frequency of cutting edges which are located e.g. at 2-3 times the distance which may, among others, be obtained by the use of nonreproducible sequences selected at random, possibly in the form of PRBS sequences.
• the invention also relates to a method of producing the tool stated in claim 2, and according to claim 9 this method is characteristic in that a considerable number of the cutting edges is removed at random from a tool with uniformly spaced cutting edges. According to claim 10 preferably at least one fourth is removed and not more than three fourths of the cutting edges are removed.
• the tool according to the invention is used for cutting machining of e.g. wood, glass, metal, plastic, meat with bone and gristle, and similar materials and may with special advantage be used with high-speed tools where the engagement frequency would be of the order of 1,000 to 10,000 Hz.
• Fig. 1 shows an embodiment of a circular saw blade for use in a back bone saw for carcasses
• Fig. 2 the noise spectrum from a back bone saw provided with this blade during sawing (solid curve) as well as the noise spectrum from a known back bone saw where the teeth are distributed uniformly along the periphery (dotted curve).
• the saw blades are clamped between two 60 mm dia. flanges in a normal back bone saw rotating the blade at a speed of approx. 4000 rev./min.
• the curve in solid line shows the noise sepctrun of the circular saw blade according to the invention.
• the curve in dotted line is recorded for a known 64-tooth blade with the same distance between the teeth.
• the dB(A) level is 1-2 dB lower
• the noise peak at approx. 8 kHz is not very irritating to the ear since it is not very sensitive at this frequency.
• this noise peak could, however, be reduced by also shifting the cutting edges in a random way so that the distance between the front edges of the cutting edges is not a multiple of one fixed distance. It may be done, for example, by constructing the complete cutting length as 128 units and then adding 1/64 to the section of each cutting edge.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sawing (AREA)
• Surgical Instruments (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8137749

Family Applications (1)

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Cited By (3)

Citations (4)

• 1981
  • 1981-11-06 DK DK490981A patent/DK151087C/da active
• 1982
  • 1982-11-05 DE DE8383901207T patent/DE3263443D1/de not_active Expired
  • 1982-11-05 EP EP19830901207 patent/EP0093171B1/en not_active Expired
  • 1982-11-05 WO PCT/DK1982/000099 patent/WO1983001587A1/en active IP Right Grant

Patent Citations (4)

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