Cutting tool holding assembly

Abstract: A cutting tool holding assembly is arranged for rapid replacement of cutting tools on machine tools. The assembly includes an adaptor (12, 14) for locating a tool holder (16) in a drive spindle (10). The adaptor has a base member (12) which is secured in the spindle (10) and a body member (14) which is secured releasably to the base member (12). The tool holder (16) is secured to the body member (14). The base member (12) is secured in the base of a bore (19) in the spindle (10) and the body member (14) is releasably secured against rotation relative to the spindle (10).

Description: This invention relates to a tool holding assembly and in particular to an adaptor for interconnecting a cutting tool holder and a drive spindle of a machine tool. Multiple spindle machine tools are used to machine successively and simultaneously work pieces, such as engine castings. Such apparatus operates continuously and the cutting tools wear and must be replaced quickly and without risk of improper placement. In US-A-4274774 there is described a cutting tool assembly especially for drilling purposes having a tool holder, a drive spindle with a bore and an adaptor. The tool holder is carried by and secured to the adaptor as a taper fit and the adaptor is mounted in the spindle. The adaptor includes a base member secured to the spindle and a body member. The body member is releasably secured to the base member by first securing means. Second securing means secures the tool holder to the body member. The base member is secured in the base of the bore of the spindle and the body member carries a sleeve which is releasably engageable with the spindle to prevent rotation of the body member relative to the spindle. The base member is of two part construction having a first part fixedly secured in the base and a second part carried by the first part. Such assemblies have operational difficulties for the user and it is an object of the invention to provide an improved tool to spindle securing assembly. According to the invention a cutting tool assembly of the afore mentioned kind is characterised in that the first and second parts have interposed between the parts resilient means whereby the second part is movable in the axial direction of the spindle, and the second part is securable to the body member by said first securing means, and the second part and the body member define between them cam surfaces whereby the body member is secured to the second part by relative rotational movement between the body member and the second part to draw the body member against an abutment on the spindle and towards the base member by the action of the resilient means. Preferably the first securing means includes a nose portion engageable with a seating having an entry portion and a locking portion, and the nose portion is on the second part of the base member which is located in the entry portion and then secured in the locking portion by relative rotation of the body member and the base member. Conveniently said sleeve is movable axially of the assembly and is resiliently biased towards said engagement position, the sleeve and the spindle comprising interengaging dogs. Preferably the first part of the base member is secured in the spindle by radially outwardly movable members carried by the first part which are selectively engageable with the walls of the bore of the spindle. An embodiment of the invention will now be described in detail by way of example only, and with reference to the accompanying drawings, in which:- Figure 1 is a diagrammatic side elevation of a tool holding assembly embodying the invention; Figure 2 is a diagrammatic sectional view of the assembly of Figure 1; Figure 3 is a detailed part-sectional view of the base member Figure 4 is a detailed side elevation of Figure 3; Figure 5 is an end view in the direction of arrow 5 in Figure 3; Figure 6 is an end view of an adaptor part of the assembly, and Figures 7-9 are diagrammatic side elevations of the assembly of Figure 1 showing the steps involved in locating the adaptor in a spindle. Figure 1 and Figure 2 show a spindle, generally designated 10, having assembled to the spindle a locating base member 12, an adaptor or body member 14 and a tool holder 16. The spindle 10 is provided with a central bore 18, and optionally with a key-way 20 along its length into which bore 18 the base member 12 is fitted and the adaptor 14 is releasably located. The base member 12 (as shown in detail in Figure 3 and Figure 4) comprises two parts, a cylindrical block 22 and a central bore member 24 extending therethrough and a pin 28 positioned at the end of the base member 12. The pin 28 is received by a correspondingly formed location hole in the base of the bore 18 of the spindle 10 and serves to orientate the base member 12 relative to the spindle 10. An alternative location member to the pin 28 may be used in the form of a key 26 and this is received by the key-way 20 in the bore 18. Formed integrally with the bore member 24 and directly above the base 12 is a nose 32. The nose 32 has a location portion 32A which is parallel-sided and extends diametrically across the base member 12. The cylindrical block 22 and central bore member 24 are secured together prior to being located into the central bore 18. This is achieved by the nose 32A locating in a slot 34 formed diametrically across the upper surface of the block 22. Once located in the slot 34, the member 24 is prevented from any rotational movement relative to the cylindrical block 22. The central bore member 24 is secured within the block 22 by the use of a compression spring 36, located by a sleeve 38 and nut 40 on the member 24. The spring 36 locates around the member 24 and between the member 24 and the base member 12 to urge the members 12 and 24 apart and allowing some relative movement therebetween. The spring 36 bears against the base of the block 22 and thus the bore member 24 is secured in relation to the block 22. The spring 36 urges the receiving surface 30 and nose 32 in a direction away from the adaptor 14 (as shown by arrow B) and provides the central bore member 24 with a degree of relative axial movement which aids the locating of the nose 32 to the adaptor 14. The sleeve 38 is adjustable in the axial direction and acts to limit the relative axial movement between the members 12 and 24. The bore member 24 may provide a coolant passage 24A through the cylindrical block 22 and in this case the members 24 extend beyond the nose 32 to engage a corresponding bore in an adjustable element 60 mounted centrally within the adaptor 14. The coolant flows up the bore 24A in the member 24, through the adaptor 14 and into the tool holder 16. This is as shown in the lower halves of Figs. 1-7. In the upper halves of these drawings the coolant passages are omitted. Positioned at opposite sides of the block 22 are two L-shaped openings 41. The L-shaped openings each have a radially directed portion which extends towards an annular groove 42 formed around the internal wall of the spindle bore 18. The openings each accommodate a ball-bearing 44 which is positioned so as to be able to protrude from the cylindrical outer surface of the base member 12 into the annular groove 42 to locate and secure the member 12 in relation to the spindle 10. The other limb of each L-shaped opening 40 is screw-threaded for receiving a correspondingly threaded grub screw 46, the inner end of which is engageable with the associated ball 44 in order to move the ball radially outwards. The adaptor 14 as shown in Figure 1 and Figure 2 has a tubular body 50 which is a close fit in the spindle bore 18. The body 50 is provided with a channel 52 which is located at the inner end of the body and which receives the nose 32 and provides a seating for and serves to secure the nose 32 of the base member 12. The channel 52 is formed with an entry portion 52A and seating portions 52B each shaped to receive the nose 32, the entry portion 52A extending diametrically across the inner end, and the seating portions 52B being arcuate slots at opposite sides of the channel 52. The surfaces 32A of the nose which engage with the seatings 52B are of cam profile, as seen in Fig. 4. Towards the other, outer end of the body 50 there is provided a tapered seating 54 which engages and seats the body 50 relative to the spindle 10. Alternatively, the body 50 is provided with angular square section seatings (not shown) which would engage and seat on a corresponding formed shoulder on the spindle 10. At the outer end of the adaptor 14 there is releasably secured a tool holder 16. An axially adjustable element 60 mounted centrally within the adaptor 14 provides a seating for the end of a tool (not shown) located in the tool holder 16 mounted within the adaptor 14. A spring biased knurled sleeve 62 having two driving dogs 65 located at diametrically opposed sides of the sleeve 62 is carried on the adaptor 14. The sleeve 62 is provided with springs 64 located in an annular opening 66 which bias the sleeve 62 in a direction away from the tool holder 16 as indicated by arrow A. The driving dogs 65 extend through slots in the adaptor 14 and are received in corresponding openings in the spindle 10 when the adaptor 14 is fully assembled with the base 12. The rotational drive required to operate the tool secured in the tool holder 16 is taken up from the spindle 10 through the drive dogs 65 alone and not through the base 12. In order to fit the base 12 into the spindle 10, the base 12 is slid into the spindle bore 18 with the pin 28 in engagement with its location hole or the key 26 in engagement with the key-way 20. This ensures that the base 12 is correctly orientated relative to the spindle bore 18 so that the adaptor 14 can be secured to the base 12 once it is located in the spindle 10. When located in the correct position in the bore 18 of the spindle 10, the base 12 is then securely fixed against withdrawal from the spindle 10 by screwing down the grub screws 46 so that they act on the ball bearings 44 urging them radially outwards to engage in the annular groove 42. This serves to lock the base 12 in position. In order to fit and secure the adaptor 14 in the spindle 10, the body 50 is placed into the spindle bore 18 until the surface 72 of the body 50 approaches nose 32. The body 50 is oriented until the nose 32 enters the channel 52. In this position the nose 32 is located in the receiving portion 52A. The adaptor 14 is pushed in against the action of the spring 64 until the nose is in the seating portion 52B. The adaptor 14 is then rotated so that the nose 32 is held in the portion 52B. At this point the dogs 65 of the knurled sleeve 62 had been engaging against the top end of the spindle 10. The rotation of the adaptor 14 through 90° causes the dogs 65 of the sleeve 62 to be urged by the spring 64 and moved in the axial direction into position in the corresponding openings in the spindle 10. Thus the adaptor 14 is held firmly for rotation with the spindle 10 by the dogs 65, the bias of the spring 64 retaining the dogs 65 in the spindle openings. The spindle is conventionally located in bearings 11, as shown in Figure 2, in the machine tool. In use, the tool holder 16 is fitted with the required tool in a conventional manner by a nut 70 which is unscrewed from the adaptor 14. The tool is placed into the jaws of the tool holder 16 and the nut 70 is screwed back down onto the adaptor 14 to secure the tool. Other tool holding means than the nut 70 and holder 16 can be used. To remove a drill holder from the spindle 10 as shown in Figures 7 to 9 the dogs 65 are drawn out of the corresponding openings in the spindle 10 against its spring bias by axial movement of the sleeve 62 and the sleeve 62 is rotated through 90° (as shown in Figures 5 to 7). The nose 32 is disengaged from the seating 52B and the adapter 14 can be released, removed and replaced without delay.

Claims: A cutting tool assembly including a tool holder (16), a drive spindle (10) with a central bore (18), and an adaptor (12, 14), the tool holder (16) being carried by and secured to the adaptor (12) as a taper fit and the adaptor (12) being mounted in the spindle (10), the adaptor comprising a base member (12) arranged to be secured against removal from the spindle (10), a body member (14) having first securing means (32, 52) for securing the body member (14) releasably to the base member (12) and second securing means for securing the tool holder (16) to the body member (14), the base member (12) being secured in the base of a bore (18) of the spindle (10) and the body member (14) carrying a sleeve (62) releasably engageable with the spindle (10) to prevent rotation of the body member (14) relative to the spindle (10), the base member (12) being of two part construction having a first part (22) fixedly secured in said bore (18) and a second part (24) carried by the first part (22), characterised in that the first and second parts (22, 24) have interposed between the parts resilient means (36) whereby the second part (24) is movable in the axial direction of the spindle (10), and the second part (24) is securable to the body member (14) by said first securing means (32, 52), and the second part (24) and the body member define between them cam surfaces (32A, 52B) whereby the body member (14) is secured to the second part (24) by relative rotational movement between the body member (14) and the second part (24) to draw the body member (14) against an abutment (54) on the spindle (10) and towards the base member (12) by the action of the resilient means (36). An assembly according to claim 1 characterised in that the first securing means includes a nose portion (32) engageable with a seating (52) formed in the body (14) and having an entry portion (52A) and a locking portion (52B), and the nose portion (32) is on the second part (24) of the base member (12) which is located in the entry portion (52A) and then secured in the locking portion (52B) by relative rotation of the body member (14) and the base member (12). An assembly according to claim 1 or 2 characterised in that said sleeve (62) is movable axially of the assembly and is resiliently biased towards said engagement position, the sleeve (62) and the spindle (10) comprising interengaging dogs (65). An assembly according to any one of the preceding claims characterised in that the base member (12) is secured in the bore (18) in the spindle (10) by radially outwardly movable members (44) carried by the first part (22) of the base member (12) which are selectively engageable with the walls (42) of the bore of the spindle (10). An assembly according to any one of the preceding claims characterised by location means (26 or 28) for orienting the base member (12) in the bore (18) of the spindle (10) relative to the axis of the assembly.

Inventors: BUTLER DENNIS ANTHONY, FORREST DAVID, JONES KEITH ANTHONY, BUTLER, DENNIS ANTHONY, FORREST, DAVID, JONES, KEITH ANTHONY, Forrest, David, c/o Morris Tooling Limited, Jones, Keith Anthony, c/o Morris Tooling Limited
Applicants: MORRIS TOOLING LTD, MORRIS TOOLING LIMITED
Application year: 1992
Main classification: B23B31
IPC codes: B23B31