GB2105278A - Track-mounted industrial robot - Google Patents

Abstract

A robot (1) is mounted on a base plate (2) which by means of recirculating ball bearings (9) and (10) can slide along a track constituted by parallel bars (3) and (4). A rail (13) extending parallel to and between the bars (3) and (4) constitutes a stator for a linear motor of which an armature (14) is mounted on the carriage.

Description

SPECIFICATION Track-mounted industrial robot This invention relates to an industrial robot of the kind which has no inherent locomotion, for example of the kind shown in British Patent Specification No.

2061872A. The object ofthe invention is to provide a comparatively simple, precise means for effecting translational movement of the robot so that the robot can perform operations in different locations.

In a preferred embodiment of the invention a machine tool comprises a robot manipulator, a carriage which supports the manipulator, a pair of parallel bars providing atrackforthe carriage, means mounting the carriage for sliding movement on the bars, and an elongate conductor extending parallel to and between the bars, said conductor-constituting a statorfor a linear motor of which an armature is mounted on the carriage.

In the accompanying drawings: Figure lisa side view of one embodiment of the invention, taken in the direction of the arrow A in Figure 3; Figure 2 is a partial front view of a track forming part of the embodiment shown in Figure 1; and Figure 3 is a partial plan view of the embodiment shown in Figure 1.

The embodiment illustrated in the drawings includes, as shown in Figure 1, a robot manipulator 1 of the kind which includes a pedestal from which extend pivoted arms terminating in a wrist which can carry a tool for operating on workpieces. Such a robot may be of the kind described in the aforementioned specification. It has no means af locomotion and is usually, as described in the aforementioned specification, mounted in a fixed location.

In this embodiment of the invention the robot 1 is mounted on a carriage which includes a plate 2. This carriage is mounted, by means to be described, for movement along two parallel bars 3 and 4 which extend adjacent the various working stations between which the robot is to be moved. The bars 3 are carried by respective rails 5 and 6 which are mutually connected by cross-ties 7 and 8.

It is normally desirable for the robot to be moved along the track constituted by the bars 3 and 4 in a programmed manner in accordance with the sequence of operations which are to be performed. However, the programming of control equipmentforthis purpose does not form any essential part of the present invention.

The carriage is mounted on the bars 3 and 4 by means of recirculating ball bushings. Those bushings 9 which engage the bar 3 are fixed to the underside of the base plate 2 but the bearings 10 which engage the bar 4 are by means of a cross-head assembly 11 arranged to be laterally floating with respect to the plate 2. It will be understood that the bars have to carry a considerable weight and although the position of the robot may be defined in the direction laterally of the track by the bar 9, slight irregularities in the distance between the bars can be accommodated by the lateral float of the bearings 10.

As is shown in Figures 2 and 3, between the carriage and each end of the track constituted by the bars is a respective bellows 12, 12a, which serves to protect the track from dust and dirt.

Extending parallelto and between the bars 3 and4 is a rail 13 which constitutes a stator for a linear motor of which the armature 14 is mounted on the carriage and is preferably mounted underneath the base plate 2. This linear motor may be controlled by controlled equipment not shown which is responsive to both command signals and also signals obtained from an "Inductosyn" linear position transducer or other position measuring device which by cooperation with a scale 1 5a or other elongate index extending lengthwise of the track provides signals indicating the position of the carriage and thereby the robot in the direction along the track.

The position sensing device may also provide signals relating to the speed of movement of the carriage as well as its position so that both position feedback and velocity feedback may be used to control the movement of the carriage. The linear motor is preferably arranged so that it can provide increments of movement of the carriage and robot lengthwise of the track.

A pneumatically operated caliper brake mechanism 16, mounted on the plate 2 and arranged to engage a rail 17 extending along thetrack beneath the carriage and to one side of the rail 13, may be provided to secure the robot in its desired working position. The operation of this brake will be included in the programmed control of the machine tool and robot.

One advantage of the described apparatus is its ability to make a long, very slow and steady movement suitable for a long, accurate weld.

The invention is not limited to any feature set forth and anything herein to the contrary notwithstanding, we reserve the right to assert monopoly in any novel and useful combination of features herein disclosed.

1. A machine tool comprising a robot manipulator, a carriage which supports the manipulator, a pair of parallel bars providing a track for the carriage, means mounting the carriage for sliding movement on the bars, an elongate conductor extending parallel to and between the bars and constituting a stator for a linear motor of which an armature is mounted on the carriage.

2. A machine tool according to claim 1 in which for mounting the carriage on the track there are provided two recirculating ball bushings for each bar, the bushings for one bar being fixed relative to the carriage and the bushings for the other bar being mounted for lateral movement relative to the bushings for the one bar.

3. A machine tool according to claim 1 or claim 2 in which the carriage has a brake cooperative with a rail extending along the track.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Track-mounted industrial robot This invention relates to an industrial robot of the kind which has no inherent locomotion, for example of the kind shown in British Patent Specification No. 2061872A. The object ofthe invention is to provide a comparatively simple, precise means for effecting translational movement of the robot so that the robot can perform operations in different locations. In a preferred embodiment of the invention a machine tool comprises a robot manipulator, a carriage which supports the manipulator, a pair of parallel bars providing atrackforthe carriage, means mounting the carriage for sliding movement on the bars, and an elongate conductor extending parallel to and between the bars, said conductor-constituting a statorfor a linear motor of which an armature is mounted on the carriage. In the accompanying drawings: Figure lisa side view of one embodiment of the invention, taken in the direction of the arrow A in Figure 3; Figure 2 is a partial front view of a track forming part of the embodiment shown in Figure 1; and Figure 3 is a partial plan view of the embodiment shown in Figure 1. The embodiment illustrated in the drawings includes, as shown in Figure 1, a robot manipulator 1 of the kind which includes a pedestal from which extend pivoted arms terminating in a wrist which can carry a tool for operating on workpieces. Such a robot may be of the kind described in the aforementioned specification. It has no means af locomotion and is usually, as described in the aforementioned specification, mounted in a fixed location. In this embodiment of the invention the robot 1 is mounted on a carriage which includes a plate 2. This carriage is mounted, by means to be described, for movement along two parallel bars 3 and 4 which extend adjacent the various working stations between which the robot is to be moved. The bars 3 are carried by respective rails 5 and 6 which are mutually connected by cross-ties 7 and 8. It is normally desirable for the robot to be moved along the track constituted by the bars 3 and 4 in a programmed manner in accordance with the sequence of operations which are to be performed. However, the programming of control equipmentforthis purpose does not form any essential part of the present invention. The carriage is mounted on the bars 3 and 4 by means of recirculating ball bushings. Those bushings 9 which engage the bar 3 are fixed to the underside of the base plate 2 but the bearings 10 which engage the bar 4 are by means of a cross-head assembly 11 arranged to be laterally floating with respect to the plate 2. It will be understood that the bars have to carry a considerable weight and although the position of the robot may be defined in the direction laterally of the track by the bar 9, slight irregularities in the distance between the bars can be accommodated by the lateral float of the bearings 10. As is shown in Figures 2 and 3, between the carriage and each end of the track constituted by the bars is a respective bellows 12, 12a, which serves to protect the track from dust and dirt. Extending parallelto and between the bars 3 and4 is a rail 13 which constitutes a stator for a linear motor of which the armature 14 is mounted on the carriage and is preferably mounted underneath the base plate 2. This linear motor may be controlled by controlled equipment not shown which is responsive to both command signals and also signals obtained from an "Inductosyn" linear position transducer or other position measuring device which by cooperation with a scale 1 5a or other elongate index extending lengthwise of the track provides signals indicating the position of the carriage and thereby the robot in the direction along the track. The position sensing device may also provide signals relating to the speed of movement of the carriage as well as its position so that both position feedback and velocity feedback may be used to control the movement of the carriage. The linear motor is preferably arranged so that it can provide increments of movement of the carriage and robot lengthwise of the track. A pneumatically operated caliper brake mechanism 16, mounted on the plate 2 and arranged to engage a rail 17 extending along thetrack beneath the carriage and to one side of the rail 13, may be provided to secure the robot in its desired working position. The operation of this brake will be included in the programmed control of the machine tool and robot. One advantage of the described apparatus is its ability to make a long, very slow and steady movement suitable for a long, accurate weld. The invention is not limited to any feature set forth and anything herein to the contrary notwithstanding, we reserve the right to assert monopoly in any novel and useful combination of features herein disclosed. CLAIMS

1. A machine tool comprising a robot manipulator, a carriage which supports the manipulator, a pair of parallel bars providing a track for the carriage, means mounting the carriage for sliding movement on the bars, an elongate conductor extending parallel to and between the bars and constituting a stator for a linear motor of which an armature is mounted on the carriage.

2. A machine tool according to claim 1 in which for mounting the carriage on the track there are provided two recirculating ball bushings for each bar, the bushings for one bar being fixed relative to the carriage and the bushings for the other bar being mounted for lateral movement relative to the bushings for the one bar.

3. A machine tool according to claim 1 or claim 2 in which the carriage has a brake cooperative with a rail extending along the track.

4. A machine tool according to any foregoing claim, including a linear position transducer arranged to provide signals denoting the position of the carriage along the track.