CUTTING TOOLS AND BLADES

Abstract: An engineers cutting tool is particularly suitable for roughing aluminium planks for aircraft. A shank (10) of alloy steel has a space therein for a blade (20) of hard metal. A wedge (22) secures the blade (20) in the space by means of a screw threaded in a blade (24). The space has a bottom edge (40) inclined to the axis of the shank (10), and a pin (42) fixed to the side. The blade (20) has an entry edge (30) for contacting the bottom edge (40) and a guide groove (not in Figure 1) for the pin (42). The longitudinal position of the blade (20) in relation to the shank (10) determines the outside or cutting diameter of the tool, and makes it possible for this diameter to be adjusted after regrinding. The blade (20) may by flat or helical.

Description: TITLE: Cutting Tools and Blades DESCRIPTION: Technical Field: The invention relates to engineers cutting tools suitable for the routing, boring, reaming, side and face cutting, or face, or straddle -milling of ferrous or non-ferrous metals, wood or plastics materials for example, and is particularly but not exclusively concerned with the roughing of aluminium planks in the construction of air or space craft- Background Art: Such tools in which a shank or block has blades removably secured thereto are known for example from Patent Specifications FR 919599 and US 2484314. The Invention: A cutting tool according to the invention comprises a shank having a space therein for receiving a blade, a wedge for securing the blade in the space, a screw OΪ-.1H for moving the wedge in relation to the shank, the space having a bottom edge inclined to the axis of the shank for contacting an entry edge of the blade, and a pin fixed in a side of the space for locking the blade in the space. A tool may have more than one such space for receiving a number of blades depending on the side and nature of the tool. The invention includes a bla de for securing in a space on such a tool, which " blade may be sold together with the tool or separately as a replacement. The blade may be flat and have a cutting edge, a bottom face, an. entry edge preferably inclined to the cutting edge, and a guide groove extending from the entry edge to a locking recess on the side of the blade for receiving a locking pin. Alternatively, the lade may be helical and have a cutting edge, a bottom face, an entry edge, and a guide groove extending as set out above for a flat blade, In either case, the entry edge may be parallel to the cutting edge. The entry edge of a flat blade should be ' inclined to the cutting edge at the same angle as the bottom edge of the space for receiving the blade. Thus the longitudinal position ' of the blade in relation to the shank determines the outside or cutting diameter of * the tool, and makes it possible for this diameter to be adjusted, O P for example after regrinding of the blade. This is. facilitated by providing the blade with a flat bottom, face for engaging a stop pin on the tool, which end may be ground away as necessary, Cooperation between the locking pin and recess ensures that the blade is safely secured in the space on the tool, and cannot be flung out if the wedge becomes loose in use. The locking recess is preferably a groove inclined to the guide groove and parallel to the entry edge, but anyway the locking recess should be shaped so as to make movement of the blade in at least two directions necessary- for its removal from the shank. ■ The tool shank is generally of alloy steel, while the blade -may be of hard metal, tungsten carbide, high speed steel, ceramic, boron nitride or polycrystalline diamond, or at least have a cutting tip of such a material. The groove and locking recess may be ground in the blade or formed therein by a powder metallurgical technique. Drawin s: Figure 1 is a side view of a tool with two blades according to the invention; Figure 2 is an end view corresponding to Figure 1; Figure 3 is a side view of the end of the tool at 90° to ' that of Figure 1; and Figure 4 comprises two side views of a blade according to the invention. Best Mode The tool of Figure 1 has a shank 10 with only one drive flat 12 visible and a threaded draw-bar hole in the left hand end. Two blades 20 are received in spaces cut in the right hand end. A wedge 22 is provided for securing each blade 20. A screw (not shown) is threaded in a hole 24 in each wedge 22 and in the shank 10 at an angle to the flat faces of the blade 20 such that tightening of the screw moves the wedge 22 and secures the blade 20. Each blade 20 and the space for receiving it respectively has an entry edge 30 and a bottom edge 40 inclined to the axis of the shank 10. A pin 42 is fixed in the side of the space, and a stop 44 at the (left hand) end. As shown in Figure 4, each blade 20 has an outside diameter cutting edge 32 and a bottom face 34 to the left. A guide groove 36 extends from the entry edge 30 to a locking recess 38 which is in the form of a groove inclined to the guide groove 36 and parallel to the entry edge 30. To the right, the blade 20 has an end cutting edge 37 and a ramping-in cutting edge 39 inclined thereto. The blade 20 is mounted in the space on the shank 10 by aligning the guide groove 36 with the pin 42 and making a first radial movement as indicated by the arrow to the left in Figure 4. After the pin reaches the closed end -of the groove 36, a second axial movement to the left as shown by the arrow at the right hand side of Figure 4 completes the positioning of the blade 20. The blade 20 is then secured by tightening a screw in the hole 24 to move the wedge 22 into the position shown. After use and regrinding of the blade 20 , the bottom face 34 •also may be ground to shorten the blade 20 and allow it to be pushed further to the left in Figure 4 on repositioning on the shank 10. The entry edge 30 slides up the bottom edge 40 of the receiving space and so makes it possible to maintain the original outside diameter of the ' cutting edge 32. C H

Claims: CIAIMS : 1. An engineers cutting tool which comprises a shank (10) having a space therein for receiving a blade (.20) , characterised by a wedge (22) * for securing the blade (20) in the space, a screw for moving the wedge (.22) in relation to the shank (10) , the space having a bottom edge (.40) inclined to the axis of the shank (10) for contacting an entry edge (.30) of the blade (20) , and a pin (.421 fixed in a side of the space for locking the blade (20) in th space. ' ■ 2. A blade (20) for securing in a space on a tool according to claim 1 * characterized by the hlade (.20) being flat and having a cutting edge (32) , a bottom " face (.34) , an entry edge C30) , and a guide groove (.36) extending from the entry edge (30) to a locking recess (.38) on the side of the blade ' (.20) for receiving a locking pin (42) . 3. A blade (20) according to claim 2 in which the entry edge is inclined to the cutting edge ( . 32) . 4. A blade (20) for securing in a space on a tool according to claim 1 characterized by the blade (.20) being helical and having a cutting edge (.32) a bottom face ( . 34) , an entry edge (30J , and a guide -groove (36) extending from the entry edge (301 to a locking recess (38) on the O... side of the blade (20) for receiving the locking pin (.42). 5. A blade (20) according to claim 4 in which the entry edge (30) is parallel to the cutting edge (32). OM?

Inventors: WALE DENNIS HARRY, WALE, DENNIS, HARRY
Applicants: MARWIN CUTTING TOOLS LTD, MARWIN CUTTING TOOLS LIMITED
Application year: 1983
Main classification: B23C5
IPC codes: B23C5