GB1605150A - Machine tool with automatic tool changing - Google Patents

Description

(54) MACHINE TOOL WITH AUTOMATIC TOOL CHANGING (71) We, DEVLIEG MACHINE COMPANY LIMITED a British company of Leicester Road, Lutterworth, Leicester Lye 17 4HE, do hereby declare the invention for which we pray that a Patent may be granted to us 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 system for the handling and storing of tools in a machine tool.

Although the invention is particularly applicable to a system working purely automatically to select and use tools from one or several alternative tool storing stations, as for example, under the control of a numerically controlled programme, it can also be applied to a semiautomatic system in which an operator intervenes, for example to load and unload tools at one or more tool storing stations, while only transfer of the tools from these stations to one or more working stations and machining operations therewith are effected automatically.

According to the invention, a tool handling and storage system in a machine tool having one or more working members each arranged for movement along an axis comprises at least one tool storage unit mounted on a support, each storage unit including a column outstanding from a surface of the support and a laterally projecting arm adapted to mount a tool for storage thereof, the arm being carried by the column so as to be displaceable longitudinally of the latter against means providing an opposing force, and the system being arranged so that transfer of tools between the storage unit and a position of operative connection with a working tool holder may be effected solely by movement of the or each working member along its axis.

In a convenient arrangement, the system includes a plurality of tool storage units and said support is also a working member at least one of the working members being movable along axes in two mutually perpendicular directions. The other member is conveniently movable along an axis extending in a direction different from those in which the axes of movement of said one member respectively extend, and preferably in a direction perpendicular to both of said two directions. Said transfer of tools from all the storage mechanisms is preferably effected solely by movement of said members along said axes.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic plan view of one form of tool handling and storing system of the invention, Figure 2 is a part-sectional elevation of one form of tool storage unit for use with the system of the invention Figure 3 is a plan view of part of the unit of Figure 2, and Figure 4 is a perspective view of part of a machine tool and a lower portion of the tool storage unit of Figures 2 and 3, illustrating details of the manner of mounting the unit.

Referring to Figure 1, this shows part of a machine tool in the form of a vertical spindle portal frame machining centre. A work-table 1 is arranged for reciprocal sliding movement along a fixed slide way 2 in the direction indicated by the double headed arrow X (X axis movement). The slide 1 would normally carry a component to be machined, as indicated at 3.

A portal frame 4 carries a machining head 5 which is mounted thereon for movement in two directions, namely that indicated by the double headed arrow Y (Y axis movement) and that represented at Z which is perpendicular to the upper surface of the work-table (Z axis movement). In the particular arrangement shown, five tool storage units A, B, C, D, E carrying respective tools a, b, c, d and e, are arranged in appropriate positions around the area of the work-table which normally supports the component 3. The storage units in this embodiment are identical in construction and operation and will be described in more detail hereinafter.

Figure 2 shows a typical embodiment of storage unit suitable for use in the system of the invention. This unit includes a cylindrical column 7 secured to a base 8 by a fastener in the form of a bolt 9. Mounted on the column 7 for reciprocal vertical sliding movement is a tubular head 10 carrying a tool support plate 11 which is secured to the head by bolts 12.

The support plate has an outwardly directed extension 13 forming an arm which is bifurcated to receive a tool 14, a recess 15 of the extension housing a flange 16 of the tool to assist in accurately locating the tool, as will be seen more clearly from Figure 3. The sub-unit, consisting of the head 10 and the support plate 11 is spring loaded relative to the column 7 by means of a coil spring 17 acting between the column and plate and the overall height of the unit and thus of the support plate 11 is adjustable by means of an adjusting screw 18 threadedly engaged in the upper end portion of the column 7. Rotation of the support plate and tubular member about the column 7 is prevented by a dowel 19 engaging in a slot 20 in the tubular member. A further dowel 21 projecting from the lower end of the column 7 can engage with alternative ones of a series of holes 22 in a flange 23 of the column to provide a number of predetermined angular positional settings of the column.

Each storage unit is secured to the worktable 1 by means of suitable Tbolts and nuts 24. Setting up of the unit may be facilitated by the provision of a tenon 25 on the underside of the flange 23, as shown more clearly in Figure 4.

Such a tenon locates in one of the usual T-slots in the work-table 1, and the upper surface of the work-table may be provided with a grid pattern 26, for co-operation with a setting mark 27 on the flange 23 to enable the unit to be accurately positioned.

For a particular machining operation, the required number of storage units are located and set up in the desired positions on the table 1, as indicated in Figure 1 by the letters A to E.

The heights of the units are adjusted by means of the screws 18 so that, for example, all the plates 11 are at the same height, although this need not necessarily be so. In order to perform a machining operation, the head 5 must be provided with a tool from one of the stations A to E and station A is selected by way of illustration. The head can be brought into position over station A by applying thereto the required degree of movement along the Y axis and moving the slide along the X axis as necessary so that the cutter spindle 28 of the head is positioned over the centre line of a tool a at station A. A predetermined downward movement of the head along the Z axis will now bring driving dogs 29 on the nose of the spindle 28 into contact with the rear face 30 of the tool flange 16, thereby depressing the cutting tool, shown generally at 31, and its associated support plate 11 against the spring 17. During this Z axis travel, the spindle is caused to rotate slowly for at least one revolution and, since there is less drag between the driving dogs 29 and tool flange 30 than there is between the tool flange and support plate 11, the dogs slip around on the stationary tool until they engage in drive slots 32 provided in the periphery of the flange 16, such engagement being assisted by the spring 17 urging the tool upwardly so that the dogs enter the slots.

When the dogs are engaged, the rotary spindle movement is ceased and a "tool lock" sequence is intiated, securing the tool into the cutter spindle. Further slight upward travel of the head along the said axis clears the flange 16 from the support plate 11 and the head is then moved along the Y axis to remove the tool from the storage unit. A cutting operation is then performed on the component 3 and, when this has been completed, the tool is returned, by appropriate movement along the aforesaid axes into the bifurcated extension of the plate 11. A "tool unlock" sequence allows the tool to fall until the flange 16 rests once more on the upper surface of the support plate, any resultant shock being absorbed by the spring 17. After ejection of the tool, the spindle rises to clear the tool shank and then, by performing an X axis movement, positions itself over the position B and the sequence described above is repeated for this position and others of the positions A to E as required by the particular machining operation being performed. All the machining and tool handling of steps in a particular sequence can be performed under full numerical control, although a certain degree of manual control can be introduced as convenient.

Various modifications can be made to the system described above without departing from the scope of the invention. For example, as an alternative to the simple adjusting screw 18 shown in Figure 1, an adjusting device incorporating an oil dash-pot may be included to give controlled upward movement to the tool support plate 11.

Tool storage units of the type described above can be used on horizontal machining centre tables, in which case a suitable gripper arm would be employed to pick up and turn the tool through 90 to present it to the cutter spindle.

It will be appreciated that the system of the invention, by using movement of working members along their respective axes to perform tool handling, avoids the use of the usual ancillary mechanisms for this purpose, all of which require additional driving means and logic systems to provide the necessary control. The system also avoids the use of a spindle orientation device to set the spindle in a precise angular position prior to tool pick up. Any number of units may be provided in desired positions and these may be programmed to the machine sequence to suit particular machining operations. Each unit may contain more than one tool. The system is capable of being used in a semi-automatic mode in which tools are loaded into and removed from the tool storage units by hand and loading into the work spindle is performed automatically.

WHAT WE CLAIM IS: 1. A tool handling and storage system in a machine tool having one or more working members each arranged for movement along an axis, said system comprising at least one tool storage unit mounted on a support, each storage

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

Claims (1)

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

   housing a flange 16 of the tool to assist in accurately locating the tool, as will be seen more clearly from Figure 3. The sub-unit, consisting of the head 10 and the support plate

   11 is spring loaded relative to the column 7 by means of a coil spring 17 acting between the column and plate and the overall height of the unit and thus of the support plate 11 is adjustable by means of an adjusting screw 18 threadedly engaged in the upper end portion of the column 7. Rotation of the support plate and tubular member about the column 7 is prevented by a dowel 19 engaging in a slot 20 in the tubular member. A further dowel 21 projecting from the lower end of the column 7 can engage with alternative ones of a series of holes 22 in a flange 23 of the column to provide a number of predetermined angular positional settings of the column.

   Each storage unit is secured to the worktable 1 by means of suitable Tbolts and nuts 24. Setting up of the unit may be facilitated by the provision of a tenon 25 on the underside of the flange 23, as shown more clearly in Figure 4.

   Such a tenon locates in one of the usual T-slots in the work-table 1, and the upper surface of the work-table may be provided with a grid pattern 26, for co-operation with a setting mark 27 on the flange 23 to enable the unit to be accurately positioned.

   For a particular machining operation, the required number of storage units are located and set up in the desired positions on the table 1, as indicated in Figure 1 by the letters A to E.

   The heights of the units are adjusted by means of the screws 18 so that, for example, all the plates 11 are at the same height, although this need not necessarily be so. In order to perform a machining operation, the head 5 must be provided with a tool from one of the stations A to E and station A is selected by way of illustration. The head can be brought into position over station A by applying thereto the required degree of movement along the Y axis and moving the slide along the X axis as necessary so that the cutter spindle 28 of the head is positioned over the centre line of a tool a at station A. A predetermined downward movement of the head along the Z axis will now bring driving dogs 29 on the nose of the spindle 28 into contact with the rear face 30 of the tool flange 16, thereby depressing the cutting tool, shown generally at 31, and its associated support plate 11 against the spring 17. During this Z axis travel, the spindle is caused to rotate slowly for at least one revolution and, since there is less drag between the driving dogs 29 and tool flange 30 than there is between the tool flange and support plate 11, the dogs slip around on the stationary tool until they engage in drive slots 32 provided in the periphery of the flange 16, such engagement being assisted by the spring 17 urging the tool upwardly so that the dogs enter the slots.

   When the dogs are engaged, the rotary spindle movement is ceased and a "tool lock" sequence is intiated, securing the tool into the cutter spindle. Further slight upward travel of the head along the said axis clears the flange 16 from the support plate 11 and the head is then moved along the Y axis to remove the tool from the storage unit. A cutting operation is then performed on the component 3 and, when this has been completed, the tool is returned, by appropriate movement along the aforesaid axes into the bifurcated extension of the plate 11. A "tool unlock" sequence allows the tool to fall until the flange 16 rests once more on the upper surface of the support plate, any resultant shock being absorbed by the spring 17. After ejection of the tool, the spindle rises to clear the tool shank and then, by performing an X axis movement, positions itself over the position B and the sequence described above is repeated for this position and others of the positions A to E as required by the particular machining operation being performed. All the machining and tool handling of steps in a particular sequence can be performed under full numerical control, although a certain degree of manual control can be introduced as convenient.

   Various modifications can be made to the system described above without departing from the scope of the invention. For example, as an alternative to the simple adjusting screw 18 shown in Figure 1, an adjusting device incorporating an oil dash-pot may be included to give controlled upward movement to the tool support plate 11.

   Tool storage units of the type described above can be used on horizontal machining centre tables, in which case a suitable gripper arm would be employed to pick up and turn the tool through 90 to present it to the cutter spindle.

   It will be appreciated that the system of the invention, by using movement of working members along their respective axes to perform tool handling, avoids the use of the usual ancillary mechanisms for this purpose, all of which require additional driving means and logic systems to provide the necessary control. The system also avoids the use of a spindle orientation device to set the spindle in a precise angular position prior to tool pick up. Any number of units may be provided in desired positions and these may be programmed to the machine sequence to suit particular machining operations. Each unit may contain more than one tool. The system is capable of being used in a semi-automatic mode in which tools are loaded into and removed from the tool storage units by hand and loading into the work spindle is performed automatically.

   WHAT WE CLAIM IS: 1. A tool handling and storage system in a machine tool having one or more working members each arranged for movement along an axis, said system comprising at least one tool storage unit mounted on a support, each storage

   unit including a column outstanding from a surface of the support and a laterally projecting arm adapted to mount a tool for storage thereof, the arm being carried by the column so as to be displaceable longitudinally of the latter against means providing an opposing force, and the system being arranged so that transfer of tools between the storage unit and a position of operative connection with a working tool holder may be effected solely by movement of the or each working member along its axis.

   2. A system according to Claim 1 including a plurality of tool storage units and in which said support is also a working member, at least one of the working members being movable along axes in two mutually perpendicular directions.

   3. A system according to Claim 2 wherein the other member is movable along an axis extending in a direction different from those in which the axes of movement of said one member respectively extend.

   4. A system according to Claim 3 wherein said different direction is perpendicular to both of said two directions.

   5. A system according to any one of Claims 2 to 4 wherein transfer of tools from all of the storage mechanisms is effected solely by movement of said members along said axes.

   6. A system according to any one of Claims 2 to 5 wherein said one member carries a machining head incorporating a machine spindle and associated gripping means for a tool and the other member is a slide for supporting a workpiece.

   7. A system according to any one of Claims 2 to 6 wherein at least one tool storage mechanism is disposed adjacent a respective one of each of a pair of mutually perpendicular sides of one of the working members.

   8. A system according to any one of the preceding claims wherein the tool mounting arm is bifurcated by a slot extending along the arm from its free end, whereby a tool carried by the arm may be engaged by gripping means and removed from the arm in the direction of lateral projection of the arm.

   9. A system according to any one of Claims 6 to 8 wherein the forward end of the machine spindle is provided with driving dogs and flanges of the tools are provided with corresponding slots for engagement by the dogs under the action of said opposing force.

   10. A system according to any one of the preceding claims wherein said means providing an opposing force is a spring acting between the column and arm.

   11. A tool handling storage system substantially as hereinbefore described with reference to the accompanying drawings.