GB1562341A

GB1562341A - Toolholder keys

Info

Publication number: GB1562341A
Application number: GB745577A
Authority: GB
Original assignee: HUTTER B
Current assignee: HUTTER B
Priority date: 1976-02-26
Filing date: 1977-02-22
Publication date: 1980-03-12
Also published as: DE2613309A1; CH600173A5; JPS52104653A; DE7609688U1; DE2613309C3; DE2613309B2

Description

(54) IMPROVEMENTS IN OR RELATING TO TOOLHOLDER KEYS (71) I, BERNHARD HUTTER, of Swiss Nationality, of Geerenstr. 14, CH 8303 Bassersdorf/ZH, Switzerland, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a key for holding a tool in a toolholder.

Screw keys for gripping taper shanks of tools have been proposed which comprise two openings situated perpendicular to one another in the screw key body and wherein two trapezoidal wedges are disposed in the one opening. The other opening is provided to receive a screw with a thread. A grub screw, movable in this opening, presses against the inner wedge. By screwing in the grub screw, the inner wedge is displaced so that the upper wedge emerges from the opening. Such screw keys appear, for example in a prospectus of Messrs. "Haueisen 8r. Sohn", Neuenburg/Wurttemberg.

It has been found, in practice, however, that certain screw keys on the market cannot be released without problems. This has frequently rendered necessary the drilling out the screw keys, as a result of which, not only is the screw key destroyed, but also the drill spindle is damaged. In addition, the drilling out requires the expenditure of several hours. Furthermore, when there are heavy axial forces or vibrations, the cone of the tool is forced a few tenths of a millimetre into the taper bore of the toolholder and as a result the screw key is no longer mounted firmly. The screw keys may then be thrown out, sometimes at high speed. This represents a considerable danger, particularly to the personnel in the vicinity.

In accordance with one aspect of the invention, there is provided a key for retaining a tool in a toolholder, comprising a body, first and second wedges arranged in a first opening in the body, the wedges being mechanically connected together for relative sliding movement, movable tightening means arranged in a second opening in the body and being operatively connected to the first wedge so that the first wedge moves with the tightening means, and means for positively locating the key body in the toolholder.

Two interengaging claws, one formed on each wedge, are particularly suitable as a mechanical connection of the wedges, and it is advantageous if the claws extend over the whole length of the inclined faces of the wedges. This construction is distinguished particularly by simple manufacture and reliable operation.

A screw member which can be countersunk in the key body is preferably provided as a tightening means. For the reliable movement of the two wedges, the screw member preferably passes through the first wedge and means are provided at the end opposite the thread for reliable return movement of the wedge. This means may, for example, be a sleeve secured to the end of the screw. The means for locating the key body in the toolholder is preferably a shoulder at the underside of the key body.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial section of a key according to the invention, Figure 2 shows a lower portion of a toolholder with tool inserted and the key of Figure 1 mounted therein, Figure 3 show a trapezoidal wedge of the key of Figure 1, Figure 4 shows a claw arrangement for interconnecting two wedges, Figure 5 shows a screw member of Figure 1 for tightening the key, and Figure 6 shows a sleeve for attachment to the member of Figure 5.

The key 1 illustrated in Figure 1 comprises a body 2 in which there are a first opening 2' and a second opening 2", the second opening 2" being partially provided with a thread 2"'. Mounted in the first opening 2' are two trapezoidal wedges 3,4 which comprise, on their inclined faces, claws 5 which interengage so that the wedges 3,4 are displaceable in relation to one another. The arrangement of the claws 5 is illustrated in Figure 3, and in Figure 4 in which one claw 5 is formed on the wedge 3 and the other on the wedge 4. The inner wedge 4 comprises a bore 4' through which there is fitted a screw 6 present in the second opening 2". The screw 6 is constructed at one end in the form of a grub screw 7 and is provided at the other end with a pin 8 on which a sleeve 9 is secured, for example by adhesion. The shapes of the screw 6 and of the sleeve 9 can be seen from Figure 5 and Figure 6, respectively.

At the underside, the body 2 comprises a shoulder 10.

For the assembly of the key 1 the trapezoidal wedges 3, 4 are first mounted so that the claws 5 interengage. Then the wedges 3A are inserted in the opening 2' of the body 2, the wedge 4 being inside with the longer of its tow parallel faces turned towards the portion of the opening 2" provided with the thread 2"'. Now the screw 6 is introduced into the opening 2" and screwed right in. The sleeve 9 is lightly coated with adhesive on its inner wall and pushed over the pin 8 of the screw 6. Care should be taken to ensure that no adhesive reaches the outer wall of the sleeve 9 or into one of the openings 2',2".Since, with the adhesives available today, it is sufficient to wet the adhering surface only partially, this requirement can easily be met.

In Figure 2, a toolholder 11 is illustrated with a tool 12, for example a drill bit, fitted in its taper bore. The key 1 is inserted in transverse slots 11',12' formed in the toolholder 11 and the tool 12, respectively, which slots are so aligned that they form a common transverse slot, in the screw key 1. The shoulder 10 engages in an opening 13 in the toolholder 11. The key 1 is illustrated in Figure 2 having an operative connection with the toolholder 11 and the tool 12.

In order to insert the key 1 the transverse slots 11',12' of the toolholder 11 and the tool 12 are first aligned so that a common transverse slot results. Then the key 1 is inserted in this transverse slot so that the shoulder 10 engages in the opening 13 in the toolholder 11. Then the screw 6 is screwed into the screw key body 2, as a result of which the inner wedge 4 urges the outer wedge 3 against an upper shank portion 14 of the tool 12. Thus the toolholder 11 is frictionally connected to the tool 12.

For the dismounting of the screw key 1, the screw 6 is unscrewed and the inner wedge 4 moves longitudinally with the screw 6. Because of the mechanical connection of the wedges 3, 4, the wedge 3 is drawn into the first opening 2' in the body 2. As a result, the key 1 acquires a sufficiently large clearance so that it can be removed from the transverse slot.

The above-described key can be installed and removed without problems and can be reliably fixed in the toolholder.

WHAT WE CLAIM IS:- 1. A key for retaining a tool in a toolholder, comprising a body, first and second wedges arranged in a first opening in the body, the wedges being mechanically connected together for relative sliding movement, movable tightening means arranged in a second opening in the body and being operatively connected to the first wedge to that the first wedge moves with the tightening means, and means for positively locating the key body in the toolholder.

2. A key according to claim 1, wherein the wedges are trapezoidal and the tightening means alternatively engages with two opposed parallel sides of the inner wedge.

3. A key according to claim 1 or 2, wherein the wedges are mechanically connected by two interchangeable claws, one formed on each wedge.

4. A key according to claim 3, wherein the claws extend respectively over the whole length of the inclined faces of the wedges.

5. A key according to any of claims 1 to 4, wherein the tightening means is screwed into the key body.

6. A key according to claim 5, wherein the tightening means comprises a member having a screw part at one end, the other end being in the form of a pin.

7. A key according to claim 6, wherein the screw part can be countersunk in the screw key body.

8. A key according to claim 6 or 7, wherein the member passes through the first wedge and has means for engagement with the first wedge at the side opposite the screw part.

9. A key according to claim 8, wherein the means for engagement with the first wedge is a sleeve secured to the pin of the member.

10. A key according to any of claims

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

Claims

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

1 for tightening the key, and Figure 6 shows a sleeve for attachment to the member of Figure 5.

At the underside, the body 2 comprises a shoulder 10.

10. A key according to any of claims

1 to 9, wherein the means for locating in the toolholder is a shoulder formed on the underside of the key body.

11. A key according to any of claims 1 to 10, wherein the second wedge prb trudes from the first opening and the first wedge is located within the housing inwardly of the second wedge.

12. A key for retaining a tool in a toolholder, constructed and arranged substantially as herein described with reference to the accompanying drawings.

13. A toolholder having a key according to any of claims 1 to 12 located in a transverse opening thereof.