Machine element or mechanism – Control lever and linkage systems – Multiple controlling elements for single controlled element
Patent
1997-07-24
1999-04-20
Herrman, Allan D.
Machine element or mechanism
Control lever and linkage systems
Multiple controlling elements for single controlled element
74606R, 901 26, 901 29, B25J 1702, F16H 5702
Patent
active
058947612
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to an industrial robot wrist unit, comprising a wrist housing, which is intended to be fixed on a distal end of a robot arm and which has two fork arms between which a tilt housing is pivotally mounted, the tilt housing supporting in turn a rotatably mounted turn-table, on which there can be mounted a distal implement, in the wrist housing there being rotatably mounted first and second drive shafts, the first drive shaft, via a first and a second gearing, being able to rotate the turntable about a first axis and said second drive shaft, via a third gearing being capable of pivoting the tilt housing about a second axis which crosses the first axis.
In previously known wrist units of the above mentioned type, the gearings have been mounted in the wrist housing so that reactive forces arising in the gearings during certain operating conditions have been able to force the fork arms apart in an undesirable manner to the detriment of the precision in positioning the tool mounted on the turntable. This can be avoided by increasing the dimensions of the wrist housing, which has, however, caused an undesirable increase in weight in the entire wrist housing.
SUMMARY OF THE INVENTION
A primary objective of the present invention is therefore to propose a wrist unit which avoids this disadvantage. For this purpose, the wrist unit described by way of introduction is characterized according to the invention in that the tilt housing is positively confined between the fork arms so that reactive forces stemming from the first, second and third gearings are prevented from pushing apart the fork arms.
Additional purposes of the present invention are for example to achieve a wrist unit of the type in question which has a wrist housing which is compact, is easier to manufacture and permits installation of gear trains and tilt housing with high precision and with fewer tolerance problems. The wrist housing has a small number of sealing surfaces and thus less tendency to leak and it makes it possible to mount the tilt housing in both fork arms.
These and other purposes are achieved in a wrist unit according to the invention which has the characterizing features disclosed in the attached dependent claims.
BRIEF DESCRIPTION OF THIS DRAWINGS
The invention will be described in more detail below with reference to the accompanying drawing, in which:
FIG. 1 is a partially sectioned longitudinal view of a wrist unit in accordance with the invention mounted on a distal end of a robot arm; and
FIG. 2 is an end view of the wrist unit shown in FIG. 1 as seen from the end of the robot arm.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, there is shown a wrist generally designated 10, for an industrial robot in accordance with the invention. The wrist 10 comprises in principle of a distal, fork-shaped wrist housing 12 with two fork arms 14 and 16, defining between them a groove-shaped space, the side walls 18,20 and bottom wall 22 of which are indicated on FIG. 1.
The wrist housing 12 is intended to be mounted on the distal end of a robot arm 24 by means of screw fasteners (not shown). FIG. 2 shows, however, four through-holes 26 for the anchoring screws in an anchoring flange 28 of the housing 12.
In the wrist housing 12 there is a so-called tilt housing 30 pivotally mounted about a transverse axis A and which supports in a manner known per se a turntable 32, which is rotatably mounted about a longitudinally oriented axis B. On the turn-table 32 there can be mounted a chosen tool (not shown), such as a welding unit, gripping means, a spray-painting nozzle or the like. The portion of the tilt housing 30 supporting the turntable 32 and its shaft 34 is thus pivotable about the axis A in the space between the fork arms 14,16 through an arc of less than 360.degree.. The axis A is oriented perpendicular to the rotational axis B of the turntable 32.
For rotation of the turntable 32, there is mounted in the wrist housing 12 a first secondary drive shaft 36 which exten
REFERENCES:
patent: 4807486 (1989-02-01), Akeel et al.
patent: 4823279 (1989-04-01), Perzley et al.
patent: 4922755 (1990-05-01), Oshiro et al.
patent: 4972735 (1990-11-01), Torii et al.
patent: 5119687 (1992-06-01), Naruoka et al.
Danielsson Stefan
Gepertz Jan
Larsson Jan
Asea Brown Boveri AB
Herrman Allan D.
LandOfFree
Industrial robot wrist unit 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 wrist unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Industrial robot wrist unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2240392