GB2188262A

GB2188262A - Universal manipulator for handling workpieces

Info

Publication number: GB2188262A
Application number: GB08607355A
Authority: GB
Inventors: Frederick Brock
Original assignee: Buckley & Taylor Ltd
Current assignee: Buckley & Taylor Ltd
Priority date: 1986-03-25
Filing date: 1986-03-25
Publication date: 1987-09-30
Also published as: GB8607355D0

Abstract

A universal manipulator comprises a base (1), a first turntable element (6) mounted for rotation on the base about a first vertical axis, a second turntable element (7) carried by the first turntable element and mounted for rotation about a second axis inclined at 45 DEG to the first axis, and a third turntable element (8) adapted to have a workpiece mounted thereon and so mounted on the second turntable element as to be rotatable about a third axis at 45 DEG to said second axis. The turntable elements may be rotatable by manual hand wheels (10, 12, 14) or, alternatively, by electrical motors. The manipulator is particularly useful for use with heavy workpieces with the centre of gravity falling within the base of the manipulator, with the electric motor drives to the different turntable elements being programmable to provide a three dimensional controllable movement of the workpiece carried on the third turntable element. The manipulator can be used in machining, welding or fabrication operations. <IMAGE>

Description

SPECIFICATION Universal manipulator This invention relates to a universal manipulator andmoreespeciallytoamanipulatorwhich is capable ofhandlingworkpiecesto position them for machining, welding and fabricating operations with the work pieces being of substantial weight.

There is a need for a manipulatorwhich not only can support a work piece for rotation about a vertical or a horizontal axis as required butwhich can also be positioned for rotating the work piece about axes intermediate the vertical and horizontal.

According to the present invention there is provided a universal manipulator comprising a base, a first turntable element mounted for rotation on said base about a first vertical, axis, a second turntable element carried by the first turntable element and mounted for rotation about a second axis inclined at 45 to said first axis, and a third turntable element adapted to have a workpiece mounted thereon and so mounted on said second turntable element as to be rotatable about a third axis at 45" to said second axis.

Preferably drive means are provided for independently rotating the first, second and third turntable elements about the respective first and second and third axes. These drive means may comprise handwheels or alternatively may comprise electric motors.

Conveniently the first and second turntables may be provided with AC electric motors as drive means and thethirdturntable may be provided with a DC variable speed electric motor as drive means.

Electronic control means may be provided for programming operation ofthe motors to control three dimensional movement of a workpiece.

Preferably, the centre of gravity of the firstturntable element is eccentrically arranged with respect to the vertical axis in order, at least partially, to counterbalance the weight of the second and third turntable elements and anyworkpiece carried by the third turntable element. The centre of gravity ofthe second turntable element is preferably eccentrically arranged with respectto the second axis whereby when the turntable elements are so positioned thatthethird axis is horizontal the centre of gravity ofthe second turntable element is in the same vertical plane as the centre of gravity ofthefirstturntable element and is at its maximum displacement towards the line of action of the centre of gravity ofthe firstturntable element.

The first and second turntable elements will normally be provided with balancing weights to compensate for the weight of a workpiece in use of a manipulator to maintain the centre of gravity of the manipulator and workpiece overthe base.

The invention will be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is perspective view of a universal manipulator embodying the present invention; Figures 2,3,4 and 5 are diagrammatic illustrations showing the manipulator in various operating positions with Figure 2 showing a workpiece supporttable in a vertical plane, Figure 5 showing theworkpiece supporttable in a horizontal position and Figures 3 and 4 indicating intermediate positions; Figure 6 is a side elevational view diagrammatically illustrating a second, powered, embodiment ofthe manipulator; and Figure 7 is an end elevational view of the manipulator of Figure 6.

Referring to Figure 1 ,there is shown a universal manipulatorwhich comprises a base (1 ) comprising a housing (2) secured to a base-plate (3) with the aid of strengthening webs (4). Afirstturntable element (6) is mounted for rotation about a vertical axis on the base (1) and carries a second turntable element (7) which is mounted for rotation relative to the turntable element (6) about an axis inclined at 45#to the vertical. Athird turntable element (8) is mounted for rotation relative to the second turntable element (7) and is in the form of a work supporttable rotatable about an axis which is inclined at 45 to the axis of rotation of the second turntable element (7).A handwheel (10) is provided for rotating thefirstturntable (6) relative to the base (1). Afu rther handwheel (12) mounted on the first turntable (6) is provided as drive means to rotate the third turntable (7) relative to thefirstturntablewhilsta third handwheel (14) carried by the second turntable element is operable to rotate the third turntable element (8). As can be appreciated from Figures 2,3,4 and 5, by rotating the second turntable (7) through 180 theturntable (8), which is adapted for carrying a workpiece, is movable from a vertical orientation as shown in Figure 2 through the intermediate orientations as shown in Figures 3 and 4 to a horizontal orientation as shown in Figure 5.

As shown in the various Figures it can be noted that the centre of gravity ofthe first turntable element is eccentrically arranged with respect to the vertical axis in order at least partially to counterbalance the weight ofthe the second and third turntable elements and workpiece carried by the third turntable element. The centre of gravity of the second turntable element is eccentrically arranged with respecttothe second whereby when the turntable elements are so positioned as forthe axis of rotation ofthethirdturntable elementto be horizontal,the centre of gravity of the second turntable element is in the same vertical plane as the centre of gravity ofthefirstturntable element and is at its maximum displacement towards the vertical line of action ofthe centre of gravity of the first turntable element. This arrangement assists in ensuring that the centre of gravity ofthe manipulatorwith a workpiece thereon is maintained within the area of the baseplate (3) so as to eliminate any tendency of the manipulator to topple when carrying a workpiece in use.

In atypical embodimentworkpieces 1.Stonnes in weight have been mounted on the third turntable element (8) with their centre gravity up to 125 mm from the face of the plate. With such a maximum load the load necessaryto rotate the handwheel was not more than 20 kg with one revolution of the handwheel The drawings originally filed were informal and the print here reproduced is taken from a later filed formal copy.

being used to drive 5 8' rotation via a worm and worm-wheel reduction gearing.

Figures 6 and 7 show an alternative, preferred, embodiment of the invention in which instead of handwheelsthedrive means forthe various turntable comprise electric motors.

Referring to Figure 6 there is shown a manipulator with thethirdturntable (8) arranged in vertical orientation so asto be rotatable about a horizontal third axis (44).The manipulator is shown as having a base comprising a cylindrical housing (2) secured to the baseplate (3) with the aid of welded webs (4). The second turntable (6) comprises a horizontal plate (33) offsetfrom a mounting plate (30) which is mounted for rotation about a vertical axis (21) by means of a bearing (31). An AC motor (20) carried by the base is provided for rotatably driving the turntable (6), the motor driving through a gearing (24) a worm engaging a worm wheel (26) secured by bolts (27) to an extension extending axially downwardly from the plate (30).

The drive forthe second turntable (7) on the first turntable (6) is similar with a motor (22) providing for rotation of the second turntable (7) about axis (40) inclined at 450 to the vertical. The motor (22) also is an AC motor.

The third turntable (8) is mounted for rotation about axis (44) which is inclined at 45' to the axis (40).This turntable (8) is rotatable by a DC electric motor (42) carried by the second turntable (7). The general gearing and drive arrangements for each turntable are similarandthus by referring to the upper partof Figure7onecanseethedrivefromthemotor(42) being passed through a reduction gear (24) to a worm (46) meshing with worm wheel (26).

Switches or other sensors, one of which is shown at (45) mounted on the base of the manipulator, are provided to sense rotational positions of the turntable elements. These are meant to limit rotation to prevent rotation entangling motor heads.

The provision of a DC variable drive to the workpiece supporting turntable (8) facilitates maximum utilization and control ofthe manipulator.

It will be appreciated thatthe use ofthe relatively inclined axes enables a workpiece carried by the turntable (8) to be presented to a working station or position in any desired inclined plane or location. By power driving theturntables simultaneously by the motors the path of approach of a workpiece surface can befullythree dimensional and changing at a preset rate forwelding, cutting or other working purposes. Thus the electric motors controlling rotation of the turntables can readily be controlled by the provision of electronic control means for programmed operation of the motors two control the three dimensional movement of a workpiece.

While as disclosed the manipulator is designed for use in carrying heavyworkpieces, for example up, to 7.5tonnes, it is aiso possibleforthe manipulatorto be constructed to be of a smaller size as a lightweight versionforuse in the robotisfield.

Claims

1. Auniversal manipulatorcomprising a base, a first turntable element mounted for rotation on said base about a first vertical axis, a second turntable element carried by the first turntable element and mounted for rotation about a second axis inclines at 450 to said first axis, and a third turntable element adapted to have a workpiece mounted thereon and so mounted on said second turntable element as to be rotatable about a third axis at 450 to said second axis.

2 Amanipulatoraccording to claim 1,wherein driverneansare provided for independently rotating saidfirst second and third turntable elements about the respective first, second and third axes.

:4. Amanipulator according to claim 2, wherein the drivemeans comprises handwheels.

4. 4. Amanipulatoraccording to claim 28gwherein the drivemea-ns comprises an electric motor.

5. A-manipulator according to claim 4,whe reinthe firstand.second turntable elements are provided with AC electri#motorsasdnve means and the third tu rntableei#ment is provided with a DC variable speed electricmotoras drive means.

6. A manipulator according to claim 5, including electronic control means for programming operation of the motorsto control three dimensional movement of a workpiece carried bythethird turntable element

7. A manipulator according to any preceding claim, wherein-the centre of gravity ofthe first turntable element is eccentrically arranged with respecs to the vertical axis in order at least partially to counterbalance the weight ofthe second and third turntable elements and anyworkpiece carried bythe third turntable element.

8. Amanipulator accordingto claim 7, wherein the centre of gravity ofthe second turntable element is eccentrically arranged with respect to the second axis whereby when the elements are so positioned as for the third axis to be horizontal the centre of gravity of the second turntable el#ement is in the same vertical plane as the centre of gravity ofthe first turntable element and is at its maximum displacementtowards the line of action of the centre of gravity ofthe first turntable element.

9. A manipulator according to any preceding claim, wherein sensors are provided to sense rotational positions of the turntable elements.

10. A manipulator according to any preceding claim, wherein the first and second turntableelements are provided with balancing weights to compensate forthe weightofa workpiece in use ofthe manipulator to maintain the centre of gravity of the manipulator and workpiece overthe base.

11. Auniversal manipulator constructed and arrangedto operate substantially as herein described with reference to and as illustrated in the accompanying drawings.