| US3293990A | 1966-12-27 | |||
| FR2242193A1 | 1975-03-28 | |||
| GB2059823A | 1981-04-29 | |||
| DE1752669A1 | 1972-07-27 | |||
| GB869183A | 1961-05-31 | |||
| US1422140A | 1922-07-11 | |||
| DE128031C |
| 1. | A work positioner comprising a frame mounted for rotation about a vertical axis, at least two work tables each of which is rotatable about an axis normal to a workface of the table, a respective motor for rotating each worktable, a respective support which permits pivoting of the respective worktable about a r horizontal axis, respective drive means for controlling the pivoting of each table and actuator means for controllably pivoting the frame about its axis whereby the frame can be moved to bring one table into a position formerly occupied by another table and vice versa. |
| 2. | A work positioner according to claim 1 in which the motor for each respective worktable is mounted on the support . |
| 3. | Awork positioner according to claim 1 or claim 2 in which the drive means comprises a respective screw jack. |
| 4. | Industrial equipment comprising a base, an industrial robot manipulator which is mounted in a fixed position on the said base and which includes arms for carrying a tool movable in a definable region, in combination with a work positioner which is mounted in a fixed position relative to the robot and which comprises a frame mounted for rotation about a vertical axis, two worktables each of which is rotatable about an axis normal to the workface of the table, the positioner being disposed such that only one of the work tables can be within said region ai_ any one time, a respective motor for rotating each worktable, two supports, each of which .carries a respective motor and v/orktable and which is mounted to pivot about a horizontal axis relative tb the frame, a respective drive motor coupled to each support for controlling the pivoting of the respective table, and actuator means for controllably pivoting * the frame about its axis whereby the positions of the • tables can be interchanged. |
| 5. | Industrial equipment according to claim 4 in which each motor is a stepping motor. |
| 6. | A work positioner according to any of claims 1 to 3 or industrial equipment according to claim 4 or claim 5 in which each worktable is removable from the respective support and is provided with a permanent work SUBSTITUTESHEET fixture. |
| 7. | A worktable which is provided with a permanent work fixture and is mounted on a support for rotation about an upright axis by means including an easily removable coupling. O PI. |
This invention relates to a work positioner which is primarily though not necessarily exclusively intended for use with an industrial robot. The invention is particularly intended to enable a manner of working in which a robot performs programmed operations on an item of work while a fresh item is prepared or loaded or unloaded from the work support at a location out of reach of the robot. The invention is particularly though not exclusively useful for use in conjunction with a robot which performs a welding operation. A presently preferred formof work positioner according to the invention comprises a frame mounted for rotation about a vertical axis, at least two work-tables each of which is rotatable about an axis normal to a workface of the respective table, a respective motor for rotating each work-table, a support which permits pivoting of the respective work-table about a horizontal axis, respective drive means for controlling the pivoting of each table, and actuating means for
SUBSTITUTE SHEET
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co trollably pivoting the frame about its axis whereby the frame is movable to bring one table into a position formerly occupied by another of. the work-tables.
There follows a description of the invention in more ^detail, with reference to the accompanying drawings, in which:*-
Figure 1 illustrates a workpositioner shown in conjunction with an industrial robot; and
Figure 2 is a plan view from above of the work positioner shown in Figure 1.
In Figure 1 of the drawings is shown a work positioner 1 inconjunction with an industrial robot 2. This industrial robot is mounted in a fixed position, though it can rotate about a vertical axis. By means of a first brachium 3 and a second brachium 4 it can move a fore arm 5 which at its distal end has a wrist 6 which can carry a tool, for example a welding head. By means of the movements of the brachia 3 and 4 and the fore arm 5 the robot 2 can perform operations in a region shown by the shaded area 7. Robots of this general character are disclosed, for example, in British Patent Specification No. 2061872A.
Robots or manipulators of the kind shown in the
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aforementioned specification are quite versatile and useful but, as shown by Figure 1, they necessarily have a restricted region of operation. It is, of course, possible to use a robot adjacent a production line but if essentially only one task is to be performed by the robot the use of a conveyor for traversing work- pieces past the robot is inconvenient and wasteful.
Certain operations, particularly welding, require rotation of the workpiece while the work is performed on it and may require pivoting of the workpiece about a horizontal axis because, for example, the welding tool cannot always reach the rear face of the workpiece.
One embodiment of the invention, which so far as it concerns construction of a work positioner is illustrated to the left-hand side of Figure 1, is intended to facilitate the simultaneous loading of a workpiece on to a work-table while another (usually similar) item of work is receiving treatment from a tool carried by a single robot. The main purpose of the work positioner shown in the left-hand part of Figure 1 is to provide two rotatable and tiltable work-tables each of which can be rapidly moved to occupy the position of the other. A more comples embodiment having more work-tables . may be feasible. The work positioner 1 is mounted on a base plate 8
which for convenience also carries the robot 2 and which rests o a floor 9. The work positioner 1 comprises a central column 10 which at its upper end carries a slew bearing 11 providing a vertical pivot axis for a frame 12. The frame 12 carries, one at each end, two rotatable work-tables 13 and 14. These are similar and in the following only one will be described in detail. The work-table 13 is mounted on a support 15 which carries a motor, preferably a stepping motor 16 which is connected by means of appropriate drive- shafts and gearing to the table 13 to effect rotation thereof about an axis normal to and preferably centrally of the upper surface of the work-table 13. One advantage of this arrangement of the support is that it may be mounted so as to be bodily tiltable and the drive for rotating the work-table can be made relatively simple. If for example the motor were to be mounted fixedly with reference to the frame 12, a much more complex drive would be necessary for maintaining rotation of the work-table while it was tilted. .The tables may be provided with slots through which the work fixtures can be bolted in the normal manner but it is also intended that the fixtures can be permanently • secured to their tables with the latter mounted on their drive shafts by easily removable couplings so that the complete table and fixture can be changed for another
different unit. This arrangement saves weight and allows an increase in the actual job weight which can be handled by the tables. It is also of use independently of the other features of the positioner. The support 15 is, together with the table 13 that it carries, tiltable about a horizontal axis provided by a pivot 18 in a bracket 17 carried at the respective end of the frame 12. The support 15 is connected by means of a hinge coupling 24 and a precision screw jack 23 to a • further motor 19 mounted on the frame 12 which by rotation of the worm in the jack effects tilting of the support and thereby tilting of the table 13 about the horizontal pivot axis.
As indicated, a similar arrangement is provided or the table 14. The table 14 is rotated by the motor 16a_ and tilted by means of the motor 13a.
Although it is feasible to arrange for 360 rotation of the frame 12 about its vertical axis, in this embodiment of the invention an actuator 20 is provided for effecting pivoting of the frame 12 comprising a rack and pinion operated by a pair of pneumatic cylinders 21 and 22. The cylinder 21 causes pivoting of the frame for 180 about its vertical pivot axis to bring the table 13 into the position formerly occupied by the table 14 and converse operation of the cylinder 22 will
pivot the frame in the reverse direction to restore the original positions of the work-tables. Thereby the robot may perform operations on the table 14 while the table 13 is loaded and vice versa. A screen 25 may be provided above the actuator 20 to protect the operator from arc flash and splatter.
Figure 2 illustrates the work positioner from above and particularly shows the disposition of the cylinders 21 and 22. It also shows the jacks 23 associated with the support 15 and frame 12, with respect to one work-table 14, a similar arrangement of parts (not shown) being provided for the other table.
Pneumatic pressure may be made available at the centre of each table by means of a coaxial line which extends axially of the work-table and is connected to a source by a flexible coupling.
The operation of the work positioner can be programmed in association with the welding operation of the robot so that an appropriate face of the workpiece located on the work-table being used, is positioned in the most suitable plane for the weld to be applied.
The invention is not limited to any feature set forth herein and anything herein to the contrary notwithstanding we reserve the right to assert monopoly in any novel useful combination of features disclosed herein.