GB1580287A

GB1580287A - Rotary cutting tool for machining the surfaces of various workpieces and materials

Info

Publication number: GB1580287A
Application number: GB2156178A
Authority: GB
Original assignee: VNII STR MAGISTRAL TRUBOPROVOD
Current assignee: VNII STR MAGISTRAL TRUBOPROVOD
Priority date: 1978-05-23
Filing date: 1978-05-23
Publication date: 1980-12-03

Description

(54) ROTARY CUTTING TOOL FOR MACHINING THE SURFACES OF VARI OUS WORKPIECES AND MATERIALS (71) We, VSESOJUZNY NAUCHNO-ISSLEDOVATELSKY INSTITUT po STROITELSTVU MAGISTRALNYKH TRUBOPROVODOV, a state enterprise organised and existing under the laws of Union of Soviet Socialists Republics, (USSR), of 19 Okruzhnoi proezd, Moscow, U.S.S.R., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates generally to cutting tools and more specifically to rotary cutting tools for machining the surfaces of cylindrical workpieces.

According to the present invention there is provided a rotary cutting tool for machining the surfaces of various workpieces and materials, comprising a number of the gangs of radially arranged resiliently flexible cutting elements made as equal-length segments held together with one of their ends forced against one another with their side surfaces, while the other (vacant) ends of said cutting elements, establish the tool cutting surface to a density lying within a range of from 0.1 to 0.99, said cutting elements in each of the gangs being held together along the outside perimeter thereof to form a ring in the tool cross section, wherein each of said gangs of cutting elements, as viewed in a longitudinal cross section thereof, is essentially two opposite trapezia spaced equidistantly from the axis of symmetry of the gang and facing said axis with their greater bases, which the ratio between the greater base of said trapezium and the lesser base thereof is determined from the following relation:

where B denotes the width of the tool cutting surface; B1 stands for the width of the surface established by the ends of the tool cutting elements held together; çl 'po = ç is the ratio between the closeness of arrangement of the butts of cutting elements on the surface established by their ends held together, and the closeness of arrangement of the ends of cutting elements on the tool cutting surface A; e indicates the length of cutting elements; D means the diameter of the tool cutting surface A.

It is due to such a constructional arrangement of the proposed tool that the contact of the tool cutting surface with the surface being treated occurs over an area which makes it possible to considerably increase tool cutting capacity and diminish the number of tools required for the entire blank perimeter to cover.

An embodiment of the present invention is set forth hereinbelow, by way of example, wit reference to the accompanying drawings, wherein; Fig. lisa schematic view of the proposed cutting tool composed of a number of the gangs of cutting elements; and Fig. 2 shows the cutting tool of Fig. 1, wherein a number of the gangs of cutting elements are aggregated into groups.

The herein-proposed rotary cutting tool for machining predominantly cylindrical work pieces (Fig. 1) comprises a number of gangs 1 of resiliently flexible cutting elements 2 made as equal-length wire segments, ends 3 thereof being forced against one another with their side surfaces, while their opposite vacant ends 4 define the tool cutting surface A to a density lying within a range of from 0.1 to 0.99.

Provided in between the side surfaces of the gangs 1 on the side of the held-together ends 3 of the cutting elements 2 are spacer rings 5 having annular recesses 6 to discharge cooling liquid and cuttings from the cutting area. The gangs 1 of the elastic cutting elements 2 along with the spacer rings 5 are enclosed in an eccentric bush 7. The cutting elements 2 may be made of round, square or rectangular section wire, or may be shaped as leaves reinforced with cemented carbide or abrasive material. Each of the gangs 1 of the cutting elements 2 is shaped as a ring whose longitudinal section is essentially two trapezia 8 spaced equidistantly from axis of symmetry of the gang and facing sais axid with their greater bases 9.In addition, the ratio between the greater base 9 of the trapezium 8 and a lesser base 10 thereof is determined from the following relation:

where B denotes the width of the cutting surface A; B1 stands for the width of the surface established by the held-together ends 3 of the cutting elements 2; çl 'po = - ç is the ratio between the density of arrangement of the butt ends of the cutting elements 2 on the surface formed by their ends 3 held together, and the density of arrangement of the butt ends of the cutting elements 2 on the tool cutting surface A; e indicates the length of cutting elements; D means the diameter of the tool cutting surface A.

The proposed tool (Fig. 2) may be composed of a number of the gangs 1 of the cutting elements 2 assembled into groups 11, so that the adjacent groups 11 of the gangs 1 are offset with respect to each other by a quantity C which is determined from the following relation: C = D - De + 2E (Il) where D stands for the diameter of the tool cutting surface A; Do denotes the diameter of the surface being treated; A means the amount of the tool interference with the surface being treated (to be found technologically).

Such a construction of the tool enables one to simplify the gear trains of the machine, as the blank is machined by virtue of the stock travelling towards the arrow E and of the tool rotation substantially around it sown axis, whereas tool rotation round the blank is negligible, mostly for changing the place of contact of the cutting surface A with the surface being machined.

The proposed constructional arrangement of the cutting tool and the ratio between the width of the tool cutting surface and the width of its surface at the held-together ends make it possible to effect the contact between the cutting surface and the surface being treated substantially over an area, and to obtain an exactly preset arrangement density of the vacant ends of cutting elements which as a whole adds much to the tool cutting capacity and enables one to reduce the number of tools required for the entire blank perimeter to cover.

Disclosed hereinbelow are some examples of practical embodiments of the tool discussed hereinbefore.

Example 1 A rotary cutting tool for peeling wire rod stock is provided, the inside diameter D of the tool cutting surface A being equal to 30 mm. The width B of its cutting surface A equals 30 mm. The factor ç of density of arrangement of the butt ends of cutting elements on the cutting surface A is equal to 0.8. Proceeding from a preset tool endurance equal to 500 operating hours let us assume the length 1 of the cutting elements equal to 25 mm. Inasmuch as a maximum possible factor ç of density of arrangement of the butt ends of cutting elements on the surface established by their ends held together, in the case where the cutting elements are made as round-wire segments, is equal to 0.906, and a practically attainable density ç, (after applying a pressing force not below 20 kgf/cm ) is equal to 0.88 or 0.9, we assume ç, to be equal to 0.9.Then find that 1 'p 0.8 - - = - = -- = 0.89. (III) cpo ç l 0.9 Then, taking into account that, according to the invention

we find that

Having substituted all the afore-stated magnitudes of the respective quantities to Equation IV, we shall obtain:

Inasmuch the surface of a gang of cutting elements, as viewed from the held-together ends thereof, assumes somewhat convexity after having been exposed to pressing, the numerical value of B1 lies within 11.5 and 12 mm.

Example 2 The rotary cutting tool made according to Example 1, is used in groups of gangs of cutting elements for treating wire rod stock featuring Do = 10 mm. In this case the amount by which one of the groups of the gangs of cutting elements is offset with respect to the other groups is equal to: C = D- Do + 2E (V) or C = 30 - 10 + 2 0.5 = 21 mm WHAT WE CLAIM IS: 1.A rotary cutting tool for machining the surfaces of various workpieces and materials, comprising a number of the gangs of radially arranged resiliently flexible elements made as equal-length segments held together with one of their ends forced against one another with their side surfaces, while the other (vacant) ends of said cutting elements establish the tool cutting surface to a density lying within a range of from 0.1 to 0.99, said cutting elements in each of the gangs being held together along the outside perimeter thereof to form a ring in the tool cross section, wherein each of the gangs of cutting elements, as viewed in a longitudinal cross section thereof, is essentially two opposite trapezia spaced equidistantly from the axis of symmetry of the gang and facing said axis with their greater bases, while the ratio between the greater base of said trapezium and the lesser base thereof is determined from the following relation:

where B denotes the width of the tool cutting surface; B, stands for the width of the surface established by the ends of the tool cutting elements held together; çl çO = ç is the ratio between the closeness of arrangement of the butts of cutting elements on the surface established by their ends held together, and the closeness of arrangement of the ends of cutting elements on the tool cutting surface A; e indicates the length of cutting elements; D means the diameter of the tool cutting surface A.

2. A rotary cutting tool as claimed in Claim 1, wherein the adjacent groups of the gangs of cutting elements are off-set with respect to each other for a distance found from the following equation: C = D-Do + 2A where D indicated the diameter of the tool cutting surface A; Do stands for the diameter of the surface being treated; A stands for the amount of the tool interference with the surface being treated.

3. A tool as claimed in any of the preceding Claims substantially as described hereinbefore with reference to, and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Then, taking into account that, according to the invention

we find that

Having substituted all the afore-stated magnitudes of the respective quantities to Equation IV, we shall obtain:

Inasmuch the surface of a gang of cutting elements, as viewed from the held-together ends thereof, assumes somewhat convexity after having been exposed to pressing, the numerical value of B1 lies within 11.5 and 12 mm.

Example 2 The rotary cutting tool made according to Example 1, is used in groups of gangs of cutting elements for treating wire rod stock featuring Do = 10 mm. In this case the amount by which one of the groups of the gangs of cutting elements is offset with respect to the other groups is equal to: C = D- Do + 2E (V) or C = 30 - 10 + 2 0.5 = 21 mm WHAT WE CLAIM IS: 1.A rotary cutting tool for machining the surfaces of various workpieces and materials, comprising a number of the gangs of radially arranged resiliently flexible elements made as equal-length segments held together with one of their ends forced against one another with their side surfaces, while the other (vacant) ends of said cutting elements establish the tool cutting surface to a density lying within a range of from 0.1 to 0.99, said cutting elements in each of the gangs being held together along the outside perimeter thereof to form a ring in the tool cross section, wherein each of the gangs of cutting elements, as viewed in a longitudinal cross section thereof, is essentially two opposite trapezia spaced equidistantly from the axis of symmetry of the gang and facing said axis with their greater bases, while the ratio between the greater base of said trapezium and the lesser base thereof is determined from the following relation:

where B denotes the width of the tool cutting surface; B, stands for the width of the surface established by the ends of the tool cutting elements held together; çl çO = ç is the ratio between the closeness of arrangement of the butts of cutting elements on the surface established by their ends held together, and the closeness of arrangement of the ends of cutting elements on the tool cutting surface A; e indicates the length of cutting elements; D means the diameter of the tool cutting surface A.
2. A rotary cutting tool as claimed in Claim 1, wherein the adjacent groups of the gangs of cutting elements are off-set with respect to each other for a distance found from the following equation: C = D-Do + 2A where D indicated the diameter of the tool cutting surface A; Do stands for the diameter of the surface being treated; A stands for the amount of the tool interference with the surface being treated.
3. A tool as claimed in any of the preceding Claims substantially as described hereinbefore with reference to, and as shown in the accompanying drawings.