Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Patent
1986-03-03
1987-11-10
Shoop, Jr., William M.
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
318565, 901 49, 901 50, G05B 1910
Patent
active
047060018
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to an industrial robot and, more particularly, to an industrial robot suitable for operation of the robot in an inflammable or explosive environment.
2. Background Art
Generally, the industrial robot is provided with drive motors which are attached on the outer wall of the robot components. Electric cables connected to the corresponding drive motors are also arranged outside the robot. Accordingly, it has been dangerous to use such a robot in an inflammable or explosive environment.
Japanese Patent Application No. 59-133002 by the present applicant discloses an industrial robot having an internally pressurized explosion proof structure for use in an inflammable or explosive environment. The robot comprises robot components such as a stationary base unit, a swiveling body unit, robot arms or the like. Motors for driving movable components of the robot and electric cables connected to the motors are respectively arranged within an airtight chamber formed in the robot, and the airtight chamber is kept at a pressure higher than an atmospheric pressure outside the robot.
Where such an internally pressurized explosive proof structure is adapted for a robot, when a pressure in the airtight chamber decreases and becomes less than an atmospheric pressure outside the robot due to a malfunction, a dangerous gas such as an inflammable gas or the like can enter the airtight chamber, and thus it is dangerous to continue operating the robot under such a malfunctioning condition.
DISCLOSURE OF THE INVENTION
According to the present invention, there is provided an industrial robot comprising: a robot assembly including a stationary robot component and a plurality of movable robot components, at least a part of the stationary robot component and the movable robot components having therein airtight chambers which communicate with each other and are intended to be kept at a pressure higher than a predetermined level which is higher than an external atmospheric pressure; robot driving motors arranged within the airtight chambers for driving the movable robot components; a driving motor controller connected to the robot driving motors by means of electric cables arranged within the airtight chambers for driving and controlling the driving motors; and means for detecting the pressure in the airtight chambers and transmitting signals to the driving motor controller to stop the robot driving motors when the pressure in the airtight chambers drops below the predetermined level.
According to the industrial robot provided by the present invention, it is possible to stop the robot driving motors arranged within the airtight chambers of the robot assembly when the pressure in the airtight chambers drops below a predetermined level. Consequently, the danger of a fire of explosion due to a leakage of an inflammable gas or the like into the airtight chambers is avoided.
The driving motors arranged within the airtight chambers may be either DC servomotors or AC servomotors. DC servomotors contain a source of ignition. Therefore, when DC servomotors are used, it is desirable to stop the motors immediately when the pressure in the airtight chamber drops below a predetermined level. Accordingly, in one embodiment of the present invention, the driving motor controller acts to electrically cut off the driving circuit of the driving motors from the power source when receiving the detecting signals from pressure switches.
AC servomotors do not contain an ignition source. Therefore, when AC servomotors are used, the respective rotational velocities thereof may be gradually reduced before they are stopped, in accordance with a predetermined program, when the pressure in the airtight chambers drops below a predetermined level and causes pressure switches to issue the detecting signals. The robot also may be stopped after one cycle of the operation thereof is completed.
The foregoing and other features and advantages of the present invention will be better understood from the ensuing de
REFERENCES:
patent: 3952759 (1976-04-01), Ottenstein
patent: 4149935 (1979-04-01), Fields
patent: 4311556 (1982-01-01), Iwamoto
patent: 4398233 (1983-08-01), Bala
patent: 4575610 (1986-03-01), Gavin
patent: 4587619 (1986-05-01), Converse
Nakashima Seiichiro
Torii Nobutoshi
Toyoda Kenichi
Fanuc Ltd.
Keane Patrick C.
Shoop Jr. William M.
LandOfFree
Industrial robot does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Industrial robot, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Industrial robot will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1070047