GB1592154A - Milling or routing cutting tools - Google Patents

Description

(54) MILLING OR ROUTING CUTTING TOOLS (71) We, NORTHERN GRINDING LIMI TED, of Whitebirk Industrial Estate, Blackburn, in the County of Lancaster, a British Company, 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 Iby the following statement: The invention relates to milling or routing cutting tools.

The invention provides a milling or routing cutting tool comprising an elongate body and at least one elongate cutting element of constant cross-section, the lbody having a longitudinally extending groove of constant cross-section, the groove and cutting element being such that the cutting element can only be inserted into the groove by sliding it along the groove in the longitudinal direction, it being impossible for the cutting element to pass out of the groove in the circumferential or radial. directions.

The cutting element may be secured in the groove, for example iby brazing or by coining or otherwise deforming the groove so that its walls grip the cutting element.

It is preferred that the tool is provided with the groove by forming the tool using an investment casting process.

The cutting element may be positioned in the groove such that part of the body lying adjacent to the mouth of the groove acts as a chip-breaker.

Preferably there are two cutting elements spaced-apart around the circumference of the tool..

By way of example, a specific embodiment of the invention will now Ibe described, with reference to the accompanying drawings, in which Figure 1 is a side view of one embodiment of milling or routing cutting tool according to the invention; Figure 2 is an end view of the tool shown in Figure 1, looking in the direction of arrow A; and Figure 3 is a view similar to Figure 2, but before the cutting elements are fitted to the tool.

Milling or routing cutting tools are well known and are generally referred to as mill ing cutters when they are used for cutting metal, and routing cutters when they are used for cutting wood. They are also some times referred to as slot drills. It is known to provide such cutters with carbide cutting tips and these are usually fitted to the shank of the cutter by machining a shoulder on the cutter and then brazing the cutting tip to the shoulder. However when the conven tional cutters are subjected to heavy loading, and particularly shock loading, it is not unknown for the brazing to shear and the carbide tip flies off at high speed. This is obviously extremely dangerous and special guards are required which make the carry ing out of certain cutting operations quite difficult.

The milling or routing cutting tool shown in Figure 1 comprises a shank 10, a head 11, and two carbide tips 12 which are mechanic wally keyed to the head 11 thereby substan tially reducing the risk that the cutting tips will fly off during use.

The two tips 12 are diametrically opposite one another and each tip is located in a groove 13 extending in the direction of the rotational axis of the tool. The cross-section of each groove is generally rectangular, but adjacent the mouth of each groove a lip 14 extends from one wall of the groove so that the mouth of the groove is smaller than the rest of the groove. Each cutting tip has a recess 15 therein which mates with one of the lips 14. It will be seen from 'Figure 2 that the Ibutt portion of each cutting tip conforms exactly in shape to the recess and the tip is therefore mechanically keyed within the recess. The tips are slid into position along the grooves and thereafter they cannot move out of position in the circumferential or radial directions without the tips or the head 11 actually breaking.When the cutting tool is rotating at high speed, it is in the radial or circumferential direction that the cutting tips will tend to fiy out.

The grooves 13 cannot readily be formed by machining, Ibut we have discovered that the shank 10 and head 11 can be formed integrally, with the grooves 13 already in position, by an investment casting process.

After the tips 12 have been slid into position, they can be secured within the grooves 13, for example by brazing, or by coining the head 11 adjacent to the grooves 13, thereby compressing the tips within the grooves and causing the walls of the grooves to grip the tips.

Since each tip is sunk within a groove, the cutting face 16 of each tip is relatively short and chips which are cut by the cutting face come up against the cylindrical periphery of the head 11 of the tool before they reach an appreciable length, and are broken off.

The cutting tool shown in the drawings thus has a chip-breaker effect.

The invention is not restricted to the details of the foregoing embodiment. For instance the shape of the cutting tips 12 and the grooves 13 may be varied. Instead of being formed in a single integral piece of metal, each groove 13 may be defined by two separate parts which are secured to h gether.

The cutting tool may have a threaded shank, instead of the plain shank.

- The cutting tool may be provided with .-only one cutting tip, or with more than two ,cutting tips.

WHAT WE CLAIM IS : - 1. A milling or routing cutting tool comprising an elongate body and at least one elongate cutting element of constant cross section, the body having a longitudinally extending groove of constant cross-section, the -groove and cutting element being such -that the cutting element can only be inserted into the groove by sliding it along the groove in the longitudinal direction, it being impossible for the cutting element to pass out of the groove in the circumferential or radial directions.

2. A cutting tool as claimed in Claim 1, in which the cutting element is secured in the groove.

3. A cutting tool as claimed in Claim 2, in which the cutting element is secured by brazing or by coining or otherwise deforming the groove so that its walls grip the cutting element.

4. A cutting tool as claimed in any one of the preceding claims, in which the tool is provided with the groove 'by forming the tool using an investment casting process.

5. A cutting tool as claimed in any one of the preceding claims, in which the cutting element is positioned in the groove such that part of the body lying adjacent to the mouth of the groove acts as a chip-breaker.

6. A cutting tool as claimed in any one of the preceding claims, in which there are two cutting elements spaced apart around the circumference of the tool.

7. A milling or routing cutting tool constructed and arranged substantially as herein described, with reference to the accompanying drawings.

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

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. position, by an investment casting process. After the tips 12 have been slid into position, they can be secured within the grooves 13, for example by brazing, or by coining the head 11 adjacent to the grooves 13, thereby compressing the tips within the grooves and causing the walls of the grooves to grip the tips. Since each tip is sunk within a groove, the cutting face 16 of each tip is relatively short and chips which are cut by the cutting face come up against the cylindrical periphery of the head 11 of the tool before they reach an appreciable length, and are broken off. The cutting tool shown in the drawings thus has a chip-breaker effect. The invention is not restricted to the details of the foregoing embodiment. For instance the shape of the cutting tips 12 and the grooves 13 may be varied. Instead of being formed in a single integral piece of metal, each groove 13 may be defined by two separate parts which are secured to h gether. The cutting tool may have a threaded shank, instead of the plain shank. - The cutting tool may be provided with .-only one cutting tip, or with more than two ,cutting tips. WHAT WE CLAIM IS : -

1. A milling or routing cutting tool comprising an elongate body and at least one elongate cutting element of constant cross section, the body having a longitudinally extending groove of constant cross-section, the -groove and cutting element being such -that the cutting element can only be inserted into the groove by sliding it along the groove in the longitudinal direction, it being impossible for the cutting element to pass out of the groove in the circumferential or radial directions.

2. A cutting tool as claimed in Claim 1, in which the cutting element is secured in the groove.

3. A cutting tool as claimed in Claim 2, in which the cutting element is secured by brazing or by coining or otherwise deforming the groove so that its walls grip the cutting element.

4. A cutting tool as claimed in any one of the preceding claims, in which the tool is provided with the groove 'by forming the tool using an investment casting process.

5. A cutting tool as claimed in any one of the preceding claims, in which the cutting element is positioned in the groove such that part of the body lying adjacent to the mouth of the groove acts as a chip-breaker.

6. A cutting tool as claimed in any one of the preceding claims, in which there are two cutting elements spaced apart around the circumference of the tool.

7. A milling or routing cutting tool constructed and arranged substantially as herein described, with reference to the accompanying drawings.