WO1988010165A1

WO1988010165A1 - Tool mounting system

Info

Publication number: WO1988010165A1
Application number: PCT/GB1988/000482
Authority: WO
Inventors: Alan Keith Wyles
Original assignee: A.K. Wyles Tooling Limited
Priority date: 1987-06-24
Filing date: 1988-06-23
Publication date: 1988-12-29
Also published as: GB8714787D0; AU1950588A

Abstract

A tool mounting system has a female connector portion (4) and a male connector portion matched to the female portion. Locking means (10) screw-threadedly engages the female portion (4) and is engageable, when the male portion is inserted into the female portion (4), with a first surface on the male portion. Releasing means (11) similarly engages the female portion (4) and is engageable with a second surface on the male portion. The mounting system is so arranged that operation of the locking means (10) draws the male connector portion into self-locking interference fit with the female portion and operation of the releasing means (11) separates the male and female portions to release the self-locking interference fit.

Description

Tool Mounting System

This invention relates to a tool mounting system which may be used for example to mount a rotary machine tool for milling, boring or other purposes or to mount a tool that is not to be rotated, for example a lathe tool. It is desirable that any such tool mounting sys¬ tem is able to mount a tool rigidly and concentrically with its axis of rotation (in the case where the tool is to be rotated). At the same time it is desirable that it should be possible to interchange tools quickly and easily. Also, it is advantageous for the tool mounting system to be arranged to allow an axial conduit through the system for coolant or lubricant.

According to the invention there is provided a tool mounting system comprising a first part having a cylindrical finely tapered female connector portion, a second part having a cylindrical finely tapered male connector portion which is matched to the female connector portion, locking means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the locking means being engagable, when the male connector portion is inserted into the female connector portion, with a first surface on the male connector portion that is inclined to the axis of the cylindrical male portion and releasing means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the releasing means being engagable, when the male connector portion is locked in the female connector portion, with a second surface on the male portion that is inclined to the axis of the cylindrical male portion, the arrangement being such that operation of the locking means draws the male connector portion into a self-locking interference fit with the female connector portion and operation of the releasing means separates the male and female connector portions to release the self-locking interference fit.

The tool mounting system of the invention enables a rigid and accurate connection to be made between the first and second parts quickly and easily. The system can be designed so as to leave free a passage along the axis of the cylindrical male and female portions (the rotary axis in the case of a rotating tool) through which coolant or lubricant can be passed to a cutting tool.

The first surface on the male connector portion that is engaged by the locking means is preferably inclined at an oblique angle to the axis of its screw thread and the second surface on the male connector portion that is engaged by the releasing means is preferably inclined at an oblique angle to the axis of its screw thread in an opposite direction to the inclination of the first surface.

The first and second parts may have surfaces which surround the female and male connector portions and confront one another when the male connector portion is inserted into the female connector portion and which are drawn into abutment with one another upon operation of the locking means. Such an additional engagement adds rigidity to the coupling between the first and second parts.

A drive pin spaced from the axis of the cylindrical male and female portions and extending parallel thereto may be provided on one of the parts and may be engagable in a recess in the other part when the male and female connector portions are locked together. Such a drive pin provides a means, in addition to the interference fit, for transmitting rotary motion from one part to the other. The drive pin may be of circular cross-section or may take the form of a key having a non-circular cross-section.

Preferably the drive pin and recess are dimen¬ sioned such that there is some play between the parts when they are initially brought together and such that upon operation of the locking means the play between the drive pin and a wall of the recess is taken up. The play is preferably taken up by arranging the engagement of the locking means and the inclined surface on the male con- nector portion to induce relative rotation of the first and second parts upon operation of the locking means.

The locking means and/or the unlocking means may comprise a conically pointed member and the inclined surface engaged by the conically pointed member may comprise a conical recess in the periphery of the cylindrical male connector portion.

In another embodiment of the invention, the locking means and/or unlocking means comprise a member having a tip of hemispherical shape, the inclined surface engaged by the member then comprising a recess of hemispherical shape in the periphery of the cylindrical male connector portion. if desired, the mounting system may comprise, in addition to the first-mentioned locking means and releasing means, a second locking means with an associated second releasing means. The arrangement will then preferably be such that the first locking means and associated first releasing means are positioned in a first region of the female connector portion and the second locking means and second releasing means are positioned in the region of the female connector portion on the opposite side of the axis from the first region. in such a mounting system, the male connector portion may have, in addition to the above-mentioned first and second surfaces, a third surface with which the second locking means is engageable and a fourth surface with which the second releasing means is engageable. While it is acceptable for either of the first and second parts to be the part carrying the tool, it is preferred for the tool to be carried by the second part, either as an integral portion of the part or as a separate member secured directly or indirectly to the part, and for the first part to be mounted directly or indirectly on the machine.

The cylindrical connector portions are preferably of circular cross-section but may be of non-circular cross- section, for example incorporating one or more flat surfaces According to another aspect of the invention there is provided a tool holder for mounting a tool, the tool holder having a cylindrical finely tapered female connector portion, locking means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread and releasing means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the tool holder being suitable for use in a tool mounting system as defined above.

According to another aspect of the invention there is provided a tool carrying member for mounting in a tool holder, the tool carrying member including a cylindrical finely tapered male connector portion which has a first surface inclined at an oblique angle to a plane perpen- dicular to the axis of the cylindrical male portion and a second surface inclined at an oblique angle to a plane perpendicular to the axis of the cylindrical male portion in an opposite direction to the inclination of the first surface, the tool carrying member being suitable for use in a tool mounting system as defined above.

By way of example a tool mounting system embodying the invention will now be described with reference to the accompanying drawings, of which: Fig. 1 is a side view of a first part of the tool mounting system comprising a tool holder, Fig. 2 is an end view of the tool holder of Fig. 1, Fig. 3 is a side view of a second part of the tool mounting system comprising a tool carrying member, and

Fig. 4 is an end view of the tool carrying member of Fig. 3. The tool holder 1 shown in Figs. 1 and 2 has a portion 2 of conventional design to enable it to be connected to a machine for rotation about the longitudinal axis 3 of the holder 1, and a female connector portion 4. The female connector portion 4 has a- recess 5 of circular cross-section concentrically positioned on the axis 3. The recess 5 is finely tapered, having a taper of 1:200 and being wider at the entrance to the recess. A pair of screw threaded through bores 6 and 7 extend radially through the female connector portion into the recess 5 and are spaced apart on a common circumference by an angle of 60°. The female connector portion has a ground flat end face 8 which surrounds the recess 5 and in which a recess defined by a blind bore 9 is provided, the blind bore being equiangularly spaced from the bores 6 and 7 at an angle of 150° from each bore.

A locking screw 10 (not shown in Fig. 1) is screw threadedly engagable in the bore 6 of the female connector portion and a similar release screw 11 (not shown in Fig. 1) is screw threadedly engagable in the bore 7. The screws 10 and 11 have respective conically pointed tips 12 and 13 which can be caused to project into the recess 5 by screwing the screws within their threaded bores.

The tool carrying member 20 shown in Figs. 3 and 4 has a portion 21, which is only shown in part and which is of conventional design carrying, either as an integral part of the member or a separate part fixed thereto, a tool such as a milling tool or boring tool, and a male connector portion 22. The male connector portion 22 is of circular cross-section and is concentrically positioned on the longitudinal axis 23 of the member, that axis being the axis of rotation of the tool. The male connector portion is finely tapered having a taper of 1:200 and being narrower at its distal end. A pair of conically shaped recesses 24 and 25 are provided in the periphery of the male connector portion and are axially spaced from one end by approximately the radius of the recesses at their widest point and circumferentially spaced apart by an angle of 60 . The member 20 has a ground flat end face 26 surrounding the male connector portion 22 and on which a drive pin 27 is provided, the drive pin being spaced from the recess 24 by an angle of 151° and from the recess 25 by an angle of 149 .

The female connector portion 4 and the male connector portion 22 are dimensioned such that the male connector portion can be inserted partway into the recess 5 until the tapered cylindrical surfaces come into contact; at this stage, the^'leading edge of the conical recess 24 in the male connector portion is just beyond the centre of the bore 6 in the female connector portion 4, the end face 8 of the tool holder 1 is spaced from the end face 26 of the tool carrying member 20 and the drive pin 27 is fitted with play in the recess 9.

In order to lock the tool carrying member 20 to the tool holder 1, the locking screw 10 is screwed into the bore 6 of the female connector portion causing the conically pointed tip 12 of the screw to enter the conically shaped recess 24 in the male connector portion and engage the inclined leading wall of that recess. Further movement of the screw 10 into the recess 5 causes the male connector portion 22 to be drawn further into the female connector portion 4 until, before the tip 12 of the screw 10 is centred in the recess 24, the end face 8 of the tool holder and the end face 26 of the tool carrying member abut one another and further tightening of the screw 10 becomes virtually impossible. As a result of the fine taper on the male and female connector portions, there is an interference fit through¬ out the interface of these portions, the interference amounting, for example, to about 10 microns. It will be noted that while the locking screw 10 and the recess 9 for the drive pin are offset by 150 , the conical recess 24 and the drive pin 27 are offset by 151 so that as the screw 10 enters further into the recess 24 the drive pin 27 is forced to become eccentrically located within the recess 9 and, in the final position of the parts, bears against a wall of the recess 9. The arrangement is such that, when the tool holder 1 is rotated in its normal direction of rotation, the rotary driving force can be transmitted through the engaged surfaces of the drive pin 27 and the recess 9. The screw 10 may be left in engagement with the conical recess 24 but, if it is removed, the male and female connector portions will remain locked together because of the narrow angle of the taper of those portions. in order to release the lock, the screw 10 is first unscrewed to remove it fully from the recess 24. The screw 11 is then screwed into the bore 7 causing the tip 13 of the screw to enter into that end of the recess 25 which is closer to the end face 26. Further movement of the tip 13 into the recess 25 forces the male and female connector portions apart and, once the screw 11 is centred within the recess 25, the interference fit between the male and female connector portions is broken and the parts can readily be separated.

Thus it will be seen that the tool holder and tool carrying member can be screwed together quickly and easily. When secured together, the interference fit between the tapered parts provides a very accurate and rigid coupling, the rigidity and accuracy of which is enhanced by the engagement of the end faces of the two parts which are spaced from the rotary axis. Although not shown in the drawings an axial conduit may be provided through the tool holder and tool carrying member to allow coolant or lubricant to be passed to the tool.

While in the described embodiment the parts have a taper of 1:200, it is not necessary for so fine a taper to be provided. For example, a fine taper of 1:50, or indeed any other self-locking taper, would be satisfac¬ tory. Although in the described embodiments the screws 10 and 11 have conical tips and the recesses 24, 25 have a corresponding conical shape, it will be appreciated that this is not essential and in each case there is only one part of each conical surface provided by the recesses 24, 25 which plays a part in the locking or releasing action.

A series of couplings of the kind shown in the drawings may be provided in series and may be desirable in certain applications.

In the description above, it has been assumed that the tool mounting system will be employed to mount a tool that is rotated in use. The system may however be used to mount a tool that is not rotated in use.

Claims

What we claim is:

1. A tool mounting system comprising a first part having a cylindrical finely tapered female connector portion, a second part having a cylindrical finely tapered male connector portion which is matched to the female connector portion, locking means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the locking means being engagable, when the male connector portion is inserted into the female connector portion, with a first surface on the male connector portion that is inclined to the axis of the cylindrical male portion and releasing means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the releasing means being engagable, when the male connector portion is locked in the female connector portion, with a second surface on the male portion that is inclined to the axis of the cylindrical male portion, the arrangement being such that operation of the locking means draws the male connector portion into a self-locking interference fit with the female connector portion and operation of the releasing means separates the male and female connector portions to release the self-locking interference fit.

2. A system as claimed in claim 1 in which the first surface on the male connector portion that is engaged by the locking means is inclined at an oblique angle to the axis of its screw thread and the second surface on the male connector portion that is engaged by the releasing means is inclined at an oblique angle to the axis of its screw thread in an opposite direction to the inclination of the first surface.

3. A system as claimed in claim 1 or 2 in which the first and second parts may have surfaces which surround the female and male connector portions and confront one another when the male connector portion is inserted into the female connector portion and which are drawn into abutment with one another upon operation of the locking means.

4. A system as claimed in any preceding claim in which a drive pin spaced from the axis of the cylindrical male and female portions and extending parallel thereto is provided on one of the parts and is engagable in a recess in the other part when the male and female connector portions are locked together.

5. A system as claimed in claim 4 in which the drive pin and recess are dimensioned such that there is some play between the parts when they are initially brought together and such that upon operation of the locking means the play between the drive pin and a wall of the recess is taken up.

6. A system as claimed in claim 5 in which the play is taken up by arranging the engagement of the locking means and the inclined surface on the male connector portion to induce relative rotation of the first and second parts upon operation of the locking means.

7. A system as claimed in any preceding claim in which the locking means and/or the unlocking means comprises a conically pointed member and the inclined surface engaged by the conically pointed member comprises a conical recess in the periphery of the cylindrical male connector portion.

8. A system as claimed in any preceding claim, wherein, in addition to the first-mentioned locking means and releasing means the system comprises a second locking means with an associated second releasing means.

9. A tool holder for mounting a tool, the tool holder having a cylindrical finely tapered female connector portion, locking means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread and releasing means screw threadedly engaging the female connector portion for adjustment along the axis of the screw thread, the tool holder being suitable for use in a tool mounting system as claimed in any preceding claim.

10. A tool carrying member for mounting in a tool holder, the tool carrying member including a cylindrical finely tapered male connector portion which has a first surface inclined at an oblique angle to a plane perpen¬ dicular to the axis of the cylindrical male portion and a second surface inclined at an oblique angle to a plane perpendicular to the axis of the cylindrical male portion in an opposite direction to the inclination of the first surface, the tool carrying member being suitable for use in a tool mounting system as claimed in any preceding claim.