Rotary cutting tool

1. A rotary cutting tool having a forward end and a rearward end and a longitudinal axis A passing through the forward and rear ends, the cutting tool comprising a cutting head, a screw member and a tool shank;

the cutting head comprising a generally cylindrical main body portion and a rearwardly extending conical portion, and an axially directed through bore having a bore surface; a plurality of axially extending and inwardly radially protruding locking wings each having a sloping locking surface protruding from the bore surface; an axially extending stopper having a tangentially facing stop surface, protruding from each locking wing;

the screw member comprises a plurality of axially extending and outwardly radially protruding clamping wings on a forward end thereof and an external screw thread rearward of the clamping wings, each clamping wing having a sloping clamping surface, and each clamping wing having an associated side abutment surface;

the tool shank having a receiving bore opening to a forward end thereof and comprising a conical forward portion and an internally threaded portion rearward of the conical portion;

wherein,

the external screw thread of the screw member is in threaded engagement with the internally threaded portion of the tool shank, the conical portion of the cutting head is located within the conical portion of the tool shank, the clamping wings and locking wings are aligned in pairs with the locking and clamping surfaces of each pair in abutment, and with each stop surface in abutment with a given side abutment surface.

2. The rotary cutting tool according to claim 1 , wherein the stopper is located at a forward end of the locking wing.

3. The rotary cutting tool according to claim 2 , wherein the stopper protrudes from the locking surface.

4. The rotary cutting tool according to claim 3 , wherein the given side abutment surface is at least a portion of a side surface of the clamping wing.

5. The rotary cutting tool according to claim 1 , wherein the stopper is located at a rear end of the locking wing.

6. The rotary cutting tool according to claim 5 , wherein the given side abutment surface is at least a portion of a side surface of a radial abutment member.

7. The rotary cutting tool according to claim 6 , wherein the radial abutment member is located adjacent the external screw thread.

8. The rotary cutting tool according to claim 5 , wherein an axial abutment member is located between consecutive radial abutment members.

9. The rotary cutting tool according to claim 1 , wherein the tool shank has a channel communicating with a screw member bore, which screw member bore communicates with radially directed coolant outlets adjacent a forward end of the screw member, the coolant outlets being aligned with recesses in the cutting head, the recesses being adjacent cutting edges of the cutting head.

10. The rotary cutting tool according to claim 1 , wherein the screw member has resilient members extending from the external screw thread to a rearward end of the screw member.

11. The rotary cutting tool according to claim 10 , wherein the rotary cutting tool is a reamer.

12. A method of assembling the rotary cutting tool of claim 1 , comprising:

positioning the screw member in the receiving bore until the external screw thread is in initial threaded engagement with the internally threaded portion;

placing the cutting head over the screw member with the locking wings passing between the clamping wings;

rotating the cutting head until the locking wings and the clamping wings are axially aligned in pairs and the stop surfaces abut the side abutment surfaces; and

further rotating the cutting head until the locking and clamping surfaces of each pair of locking and clamping wings are in abutment and the screw member is fully screwed into the internally threaded portion thereby securing the cutting head to the tool shank.

13. A rotary cutting tool assembly comprising a cutting head, a screw member and a tool shank, wherein:

the cutting head has a forward end and a rearward end, and comprises a generally cylindrical main body portion, a rearwardly extending conical portion, an axially directed through bore having a bore surface; a plurality of axially extending and inwardly radially protruding locking wings each having a sloping locking surface protruding from the bore surface; and an axially extending stopper having a tangentially facing stop surface, protruding from each locking wing;

the screw member has a forward end and a rearward end, and comprises a plurality of axially extending and outwardly radially protruding clamping wings and an external screw thread rearward of the clamping wings, each clamping wing having a sloping clamping surface, and each clamping wing having an associated side abutment surface;

the tool shank having a receiving bore opening to a forward end thereof and comprising a conical forward portion and an internally threaded portion rearward of the conical portion; and

the rotary cutting tool assembly is adjustable between a disassembled position in which the cutting head, screw member and tool shank are unconnected to one another and an assembled position in which the external screw thread of the screw member is in threaded engagement with the internally threaded portion of the tool shank, the conical portion of the cutting head is located within the conical portion of the tool shank, the clamping wings and locking wings are aligned in pairs with the locking and clamping surfaces of each pair in abutment, and with each stop surface in abutment with a given side abutment surface.