Cutting tool and tool holder

Abstract: A cutting tool (1), has a head (2) with an elongate shaft (3) by which the tool (1) can be engaged with a tool holder, the head (2) being offset from the shaft (3) at a shoulder (5) which serves, by abutment with the tool holder, to position the tool (1) relative to the tool holder. The cutting tool (1) is advantageous primarily in that it can be easily and securely positioned in the tool holder for use.

Description: This invention relates to a combination of a tool holder and remorably fitted cutting tool, as described in the preamble of claim 1. Such a combination is known from document EP-A-0 259 847. It is well known for cutting tools, in particular relatively small cutting tools such as parting-off tools, to comprise inserts which are interchangeably mounted in tool holders. The tool holders in turn are mounted in the machine tool, eg a lathe. In one arrangement of this type, the tool insert is held in a slot formed in the side of the tool holder. In order to position the tip of the tool insert correctly this slot is arranged at an angle to the longitudinal axis of the tool holder, and this leads to reduced mechanical strength. In addition, correct positioning of the tool insert within the holder may be difficult or impossible to achieve reliably since it depends on abutment of the end of the tool insert with the end face of the slot and if that end of the tool insert becomes worn or damaged then the insert may be incorrectly positioned. There has now been devised improvements to machine tool inserts which overcome or substantially mitigate these and other disadvantages of the prior art. According to the invention, there is provided a combination as indicated in claim 1. The combination according to the invention is advantageous primarily in that the cutting tool can be easily and securely positioned in the tool holder for use. In addition, the tool can be aligned with the shaft positioned parallel to the longitudinal axis of the tool holder. The slot is preferably provided in a side face of the body and is preferably formed with surfaces which co-operate with corresponding surfaces of the shaft to provide lateral retention of the shaft within the slot. The means for securing the tool within the tool holder preferably comprises clamping means. Most preferably, the end of the tool holder which receives the tool is split along the axis of the slot to form a pair of jaws which can be drawn into retaining engagement with the tool, eg by a threaded fastener. The invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a side view of a cutting tool; Figure 2 is a front end view of the cutting tool of Figure 1; Figure 3 is a plan view of the cutting tool of Figure 1; Figure 4 is a side view of a tool holder with which the tool of Figure 1 is used; Figure 5 is a plan view of the tool holder of Figure 4; and Figure 6 is a sectional view on the line VI-VI in Figure 4. Referring first to Figures 1 to 3, a cutting tool is generally designated 1 and comprises a head 2 with a shaft 3. The shaft 3 has chamfered longitudinal edges by which it is retained in a tool holder in the manner described below. The cutting tip 4 of the head 2 is offset from the shaft 3, there being a shoulder 5 at the junction of the shaft 3 and head 2. As can be seen from Figures 2 and 3, the shaft 3 is of greater thickness than the head 2. Turning now to Figures 4 to 6, a tool holder with which the cutting tool of Figures 1 to 3 is used is generally designated 10 and comprises an elongate body 11 of generally square cross-section. The body 11 is formed at the end which receives the cutting tool 1 with a transverse slot 12 which divides that end of the body 11 into a pair of clamping jaws 13,14. A countersunk bore 15 extends vertically (as viewed in Figure 6) through the clamping jaws 13,14. The portion of the bore 15 which lies in the lower clamping jaw 14 is threaded. A clamping bolt (not shown) is engaged in the bore 15 and is used to draw the clamping limbs 13,14 towards each other in a clamping action. The body 11 is also formed, along one side of the end which receives the cutting tool 1, with a longitudinal slot 17. The slot 17 is of trapezoidal cross-section, corresponding in form to the cross-section of the shaft 3. The slot 17 terminates in a circular recess 18 formed in the side of the body 11. The cutting tool 1 is fitted to the tool holder 10 as follows. With the clamping screw (not shown) loosened or absent from the bore 15, the shaft 3 of the tool 1 is slid into the longitudinal slot 17 in the side of the body 11 until the shoulder 5 abuts the end of the body 11. The free end of the shaft 3 is then accommodated within the recess 18. The tool 1 is retained laterally by the chamfered shape of the slot 17 and shaft 3, and the clamping screw is then tightened until the clamping action of the jaws 13,14 holds the shaft 3 firmly in place. When mounted in the tool holder 10 in this manner, the cutting tip 4 of the cutting tool 1 is positioned in line with the upper edge of the body 11, yet the cutting tool 1 is aligned parallel to the longitudinal axis of the tool holder 10. The head 2 of the cutting tool 1 is positioned reliably by abutment of the shoulder 5 with the end of the body 11 and is not affected by damage or wear to, for instance, the free end of the shaft 3. The tool holder 10 may be mounted in a machine tool in a conventional manner.

Claims: The combination of a tool holder and removably fitted cutting tool, the tool holder (10) comprising an elongate body (11) provided with a slot (17) adapted to receive the shaft (3) of the tool (1), and means for securing the tool within the tool holder, the cutting tool (1) including a head (2) which is offset from the shaft (3) by a shoulder (5) which serves, by abutment with the tool holder, to position the tool (1) relative to the holder (10), characterised in that the slot is disposed parallel to the longitudinal axis of the body the top of the tool (1) includes a cutting tip (4) which is in line with both the lateral extent of the shoulder (5) and with the upper edge of the body (11), and the cutting tool is aligned parallel to the longitudinal axis of the body (11). The combination of a tool holder and removably fitted cutting tool according to claim 1, characterised in that the shaft (3) has chamfered longitudinal edges. The combination of a tool holder and removably fitted cutting tool according to claim 1 or claim 2, characterised in that the shaft (3) is of greater thickness than the head (2). The combination of a tool holder and removably fitted cutting tool according to any one of claims 1 to 3, characterised in that the slot (17) is provided in a face of the body. The combination of a tool holder and removably fitted cutting tool according to any one of claims 1 to 4, characterised in that the slot (17) is formed with surfaces which cooperate with corresponding surfaces of the shaft (3) to provide lateral retention ofthe shaft (3) within the slot (17). The combination of a tool holder and removably fitted cutting tool according to any one of claims 1 to 5, characterised in that the end of the tool holder which receives the tool is split along the axis of the slot (17) to form a pair of jaws (13,14) which can be drawn into retaining engagement with the tool (1) The combination of a tool holder and removably fitted cutting tool according to claim 6, characterised in that a threaded fastener is used to draw the pair of jaws (13,14) into retaining engagement with the tool (1).

Inventors: LONDON KEITH, LONDON, KEITH
Applicants: ADVANCED CARBIDE TOOLING LTD, ADVANCED CARBIDE TOOLING LTD.
Application year: 2000
Main classification: B23B27
IPC codes: B23B27