IL21939A

IL21939A - Tool

Info

Publication number: IL21939A
Application number: IL2193964A
Authority: IL
Original assignee: Espa Establishment For Securit
Priority date: 1963-08-21
Filing date: 1964-08-19
Publication date: 1968-04-25
Also published as: CH462589A; BE652147A; NL6409284A; BR6461755D0; DE1256514B; GB1011658A; AT242471B

Description

This invention features a tool which has a cut-out portion at one end of a tool shaft which is used to accommodate an indexable and reversible, flat cutting tool (cutting tip), which has a hole in it, and which has at least two side surfaces, which meet each other at an angle* clamped against two corresponding limiting stops of the cut-out to determine the align ment of the cutting tip which is held in the cut-out by the eccentric pin of a rotatable bolt which is tightened up in a hole in the tool shaft.

Tools of this type are already familiar; in this type the eccentric presses the rear edge of the cutting tip against the adjoining edge of the tool shaft cut-!-out and thereby holds it. The hole in the cutting tip has no play in relation to the eccentric. For this reason the cutting tool, since the eccentric will move transversely when the bolt is turned, also moves transversely in the same manner, and it will do this along the rear edge of the cut-out in the tool hole. Such uncertainty in the positioning of the tip on the holder cannot, in many cases, be tolerated when these familiar tool holders are being used, e.g., as in the case of transfer and automatic feeds.

Cutting-tip mountings which depend on eccentrics and in which the eccentric is of a smaller diameter than the corresponding hole in the cutting tip are also known. In this type of construction the rhomboid cutting tip, due to the small difference between the diameters of the eccentric and of the hole in the cutting tip, will "be more likely to make a turning or transverse movement which causes one of its edges to "be tightly pressed against the respective limiting edge of the cut out while its other edge is not engaged by the other limiting edge of the cut out. In practice it has been proved that in such cases the cutting tip will be secured whilst it is slanted and thus proper positioning will be lost.

In order to provide a remedy, the invention provides a tool comprising a shaft with a cut-out portion at one end which accommodates an indexable and reversible flat cutting tip having a hole in it and at least two side surfaces forming an angle so that the side surfaces are clamped against corresponding limiting stops of the cut-out to align the cutting tip which is retained in the cut-out by means of an eccentric pin of a rotatable bolt in a hole in the tool shaft, the hole in the cutting tip having such a shape that it provides at least one flat bearing surface for the eccentric pin.

It is advantageous if the flat bearing surface of the hole in the cutting tip is perpendicular to the angular bisector of the angle formed by the side surfaces. This will ensure that no transverse movement of the tip occurs during clamping.

Further details of the invention are provided by means of the following descriptions and accompanying drawings.

Pig. 1 A side elevation of the tool holder with a cutting tip clamped to a tool shaft.

Pig. 2 A plan view of Fig. 1 · Pig. 3 An enlarged plan view of part of the tool.

Pig. A section along the line of Pig. 3» at a reduced scale.

Pig.5 A plan view of part of the topi holder with a rhomboid cutting tip clampled to its tool shaft.

Pig. 6 A section along the line 6-6 of Pig. 5· A tool shaft 10, made of square-sectional material, has a short obtuse angled off-set section 10a at one end. This off-set section has a flat, triangular cut-out portion 10b, which has a bearing surface 10c sloping downwards toward the end of the tool shaft. The depth t of the cut-out 10b is of the same order as the height h of the cutting tip 11, which, being triangular in shape, fits into the cutting 10b, although one side 11a of the cutting tip protrudes slightly beyond the off-set section 10a of the tool holder 10, and this is held in position by a method which is the subject of a later explanation.

A two-stage bore 10g which penetrates the tool shaft, is perpendicular to the bearing surface 10c. One part 10ga of this bore Is short in relation to the overall length of the bore 10g, -witieh has a larger diameter and which emerges at the triangular surface l c. The axiB of the bore cuts the angular bisector of both side surfaces (limiting stops 10θ and 10f of the cutout 10b). At the point where the surfaces 10e and 0f would meet, the tool shaft 10 is provided with a clearing slot 0h.

A pivot pin 12 ia fitted in the two-stage bore Og. This consists of a single unit consisting of a bolt seotion 12a, a narrow flange 12c and an eccentric pin 2d the face of the bolt section 2a has at its end remote from the eccentric pin d a blind hole 12b in the shape of a hexagon; this hole serves for the insertion of a correspondingly-shaped turning key; the flange 2c is formed in such a way that it can be fitted into the step 10ga between the two diameters of the bore. When it is in position it terminates flush with the bearing surface 10e. The eccentric pin 2d protrudes into a receiving hole 1 d in the triangular cutting tip 11 which can be mounted in Various positions and also reversed (Pig. 3)· This receiving hole is located symmetrically to the bisectors of the three edges of the cutting tip 11 and presents three side surfaces 1 e of equal length, and these are joined to each other by the arcs 11f.

In order that the cutting tip 11 can be clamped in the cut-out of the tool shaft the configuration of the cylindrical eccentric pin as far as range and eccentricity are concerned, and the configuration of the internal surface of the hole 11d, are such that when the bolt 12 is turned the eccentric pin 2d engages that one of the three flat bearing surface 11e (11 ea in Pig. 1-4*) which is perpendicular to the bisector of the angle between the side surfaces 1 a of the cutting tip abutting against the side surfaces 10e and 10f of In this example one of the side surfaces (10Θ or lOf) will serve as a base (clamping surfaces) and the other as a positioning point for the sliding movement of the cutting tip along the clamping surface, depending on the direction in which the eccentric is rotated. This results in the fact that when the triangular tip is tightened it will always arrive as a snug fit in the angle formed by the side surfaces of the cut-out portion 10b. Thus it is possible to change the cutting tip or to change its position without dismantling the tool shaft and taking it out of its setting, thereby maintaining the prescribed cutting position* A rhomboid cutting tip 111 is Illustrated in Figures 5 and 6. This Is set up In a suitable tool shaft 100· Since this type of cutting tip can only be turned once, unlike the cutting tip which is shaped like an equilateral triangle, only two flat bearing surfaces 111 e are provided in the cutting tip hole* In the case of a square cutting tip four flat bearing surfaces would be provided, etc.

In the type of example shown here the cutting tip will in each occasion be pressed into an angle which is formed by the side surfaces of the shaft cutout. However, it is possible to adapt the invention in such a way that a cut-out is provided with only one side surface against which the corresponding side surface of the cutting tip will be clamped by means of pressure which is perpendicular to the side surface. In this case a projection is provided on the side surface and this projection then forms a positioning point against which the cutting tip is moved alone the clamping Burface before the eccentric is clamped* .

The clamping method described here cannot only be used in the case of rod shaped tool shafts, but can also be used for milling cutters drilling tools etc., that is to say, it can be used in any case where changeable cutting tips have to be clamped in position on a holder* As a rule the cutting tips in question are usually formed from sintered hard metal in which case the chip breaker Hg is also formed in a sintered casting*

Claims

HAVING HOW particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we olaim is

1. A tool comprising a shaft with a cut-out portion at one end which accommodates an indexable and reversible flat cutting tip having a hole in it and at least two side surfaces forming an angle so that the side surfaces are clamped against corresponding limiting stops of the cut-out to align the cutting tip which Is retained in the cut-out by means of an eccentric pin of a rotatable bolt in a hole in the tool shaft, the hole In the cutting tip having such a shape that it provides at least one flat bearing surface for the eccentric pin. 2· A tool acoording to claim 1 in which the or each flat bearing surface of the hole in the outting tip is perpendicular to the angular bisector of said angle forming side surfaces. 3» A tool substantially as herein described with reference to the accompanying drawings. Dated this Nineteenth day of August 196 A.E. MULFORD Agent for Applicants