U.S. patent application number 09/820103 was filed with the patent office on 2001-10-04 for weight compensation device.
Invention is credited to Bohlken, Wolfgang.
Application Number | 20010025541 09/820103 |
Document ID | / |
Family ID | 7636713 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010025541 |
Kind Code |
A1 |
Bohlken, Wolfgang |
October 4, 2001 |
Weight compensation device
Abstract
For providing an improved weight compensation for a robot, the
invention provides a weight compensation device on a robot, which
is characterized by a plurality of parallel tension-proof,
pressurized hose elements fixed by their ends to common fixing
elements.
Inventors: |
Bohlken, Wolfgang;
(Friedberg, DE) |
Correspondence
Address: |
McGLEW AND TUTTLE
SCARBOROUGH STATION
SCARBOROUGH
NY
10510-0827
US
|
Family ID: |
7636713 |
Appl. No.: |
09/820103 |
Filed: |
March 28, 2001 |
Current U.S.
Class: |
74/490.01 |
Current CPC
Class: |
F15B 15/103 20130101;
B25J 9/142 20130101; B25J 19/0012 20130101; Y10T 74/20305 20150115;
F15B 15/1404 20130101; B25J 9/1075 20130101 |
Class at
Publication: |
74/490.01 |
International
Class: |
B25J 018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2000 |
DE |
100 15 411.5 |
Claims
1. Device for weight compensation on a robot, characterized by at
least one tension-proof, internally pressurized hose element (6)
fixed by fixing elements (7, 9; 8, 10).
2. Device according to claim 1, characterized by a plurality of
tension-proof, pressurized hose elements (6) fixed by their ends to
common fixing elements (7, 9; 8, 10).
3. Device according to claim 1, characterized in that the hose
elements have a flexible, gas-tight inner hose (6.1) and
tension-proof fibres (6.2) surrounding it.
4. Device according to claim 3, characterized in that the
tension-proof fibres (6.2) are oriented to the axis of the hose
elements (6) by a finite angle not equal to 0.degree..
5. Device according to claim 3, characterized in that the fibres
(6.2) are arranged in rhombic manner.
6. Device according to claim 1, characterized in that the hose
elements (6) have an outer, flexible protective jacket (6.3).
7. Device according to claim 1, characterized in that the hose
elements (6) coaxially surround a central axis (B) common
thereto.
8. Device according to one of the preceding claims, characterized
in that the fixing elements have plates (7, 8), with which the hose
elements are connected in tension-proof, but detachable manner.
9. Device according to claim 1, characterized in that the fixing
elements have eyelet attachments (9, 10) for fixing to parts of a
robot.
10. Device according to claim 9, characterized in that one eyelet
attachment (9) is connected to a robot carrousel and the other
eyelet attachment (10) is articulated to the rocker (2) of a robot
eccentric to its A2 axis.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a weight compensation device on a
robot.
BACKGROUND OF THE INVENTION
[0002] Weight compensation means are provided on a robot, so that
the motors for the individual elements only carry out the movement
work and only have to compensate to a limited extent or not at all
forces and torques caused by gravitation. This more particularly
applies to the rocker of a robot and its movement about the
horizontal A2 axis relative to the robot carrousel and base.
[0003] As weight compensation means have been provided or proposed
counterweights, mechanical springs, fluid springs in the form of
pneumatic and hydraulic cylinders with pistons movable axially
therein, magnetic systems, as well as lever and cable systems.
[0004] Each of the known weight compensation means suffers from
disadvantages. Thus, counterweights require a large amount of space
and also increase the mass and inertia of the overall robot.
Mechanical springs are relatively large if they are to apply the
necessary forces and consequently have a considerable size. Fluid
springs are not maintenance-free and may require the connection to
a pressure medium, e.g. in a pressure container. Lever and cable
systems are complicated and costly. Magnetic systems are also
relatively large.
[0005] The problem of the invention is to provide a weight
compensation device which, whilst avoiding the aforementioned
disadvantages and whilst requiring little space and having a low
weight, more particularly ensures a high flexibility in use.
SUMMARY OF THE INVENTION
[0006] According to the invention the set problem is solved by a
weight compensation device on a robot by at least one
tension-proof, internally pressurized hose element fixed by fixing
elements and where in particular a plurality of parallel
tension-proof, pressurized hose elements fixed by their ends to
common fixing elements are provided.
[0007] Apart from a limited space requirement due to the slender
construction provided by the invention the device has a limited
weight and is also maintenance-free. It is also substantially free
from wear. As a result of the tight construction of the hose
elements it can also be used in clean rooms. It is also easy to
manufacture and inexpensive. Moreover no lubricants are required.
In the device according to the invention high flexibility results
from the fact that the length can easily be chosen as a function of
the intended use and the filling pressure can be easily adapted
according to the intended use. As a result of the slender
construction it is also possible to incorporate the device
according to the invention into a rocker or arm of a robot, i.e. it
can be incorporated into its carrying elements, such as walls.
[0008] The hose elements provided according to the invention can
have numerous different constructions. According to a preferred
development the hose elements have a flexible, gas-tight inner hose
and tension-proof fibres surrounding it and the tension-proof
fibres are in particular oriented under a finite angle unequal to
0.degree. with respect to the hose element axis. Advantageously a
fibrous structure is provided in which the individual fibres cross
one another, so that they have a rhombic arrangement. Although not
absolutely necessary, according to a preferred development of the
invention in addition to the gas-tight inner hose surrounded by the
fibrous structure, there is an outer, flexible jacket surrounding
both the fibrous structure and the gas-tight inner hose so as to
protect them against action from the outside.
[0009] Whilst there are also numerous arrangement possibilities for
the hose elements in the device according to the invention, whereby
the hose elements can e.g. be tightly juxtaposed as a group,
according to an extremely preferred development the hose elements
coaxially surround a central axis common thereto. According to a
further development the fixing elements have plates with which the
hose elements are connected in tension-proof, but detachable
manner. The fixing elements in particular have eyelet attachments
for fixing to parts of a robot. As a result of such fixing elements
the device according to the invention can be easily fixed to parts
of a robot and can in particular subsequently be detached
therefrom. According to a highly preferred development of the
invention one eyelet attachment is connected to the carrousel of a
robot and the other eyelet attachment is articulated to a robot
rocker eccentrically to its A2 axis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Further advantages and features of the invention can be
gathered from the claims and following description of an embodiment
of the invention with reference to the attached drawings, wherein
show: FIG. 1 A carrousel and rocker of a robot together with a
device according to the invention.
[0011] FIGS. 2 & 3 Two variants of the coupling of several hose
elements in a hose group corresponding to a section A-A of FIG. 1
viewing in accordance with arrows A, A.
DETAILED DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows the rotary table or carrousel 1 of a robot.
Such a carrousel 1 is placed on a not shown robot base and is
rotatable relative thereto about the vertical A1 axis. The rocker 2
is articulated to a robot carrousel 1 and is pivotable about the
horizontal A2 axis of the robot at the lower end thereof. A motor
is provided for pivoting the rocker 2. To ensure that the motor
only has to carry out the pivoting work during the pivoting of the
rocker 2 and does not have to completely compensate the forces or
torques caused by gravitation, a weight compensation means 4 is
regularly provided for a robot between the carrousel 1 and the
rocker 2, being articulated thereto eccentrically to the A2
axis.
[0013] The weight compensation means 4 has, in the embodiment
shown, a device with a plurality of parallel hose elements 6, which
are preferably, as in the embodiment shown, arranged coaxially to
an axis B surrounding the same. The ends of the hose elements 6 are
fixed in tension-proof manner to the connection plates 7, 8, which
are in turn connected in one piece or firmly to the eyelet
attachments 9, 10. The eyelet attachment 9 is firmly articulated to
the carrousel 1 or a constructional element 1a thereof. The eyelet
attachment 10 is articulated to the rocker 2 and, as stated,
eccentric to the A2 axis.
[0014] The hose elements 6 have a gas-tight inner hose 6.1, which
is surrounded by a rhombic pattern of tension-proof fibres 6.2,
which in the embodiment shown is in turn enclosed by a protective
jacket 6.3. At their ends the hose parts 6.1 to 6.2 are connected
in tension-proof manner to connecting elements 6.4 and 6.5. One of
the connecting elements 6.5 is completely closed. In the case of
the other connecting element 6.4, there is a connection 6.6 for
filling the hose element 6. It can consequently be screwed using
corresponding screw thread pins to the connection plates 7, 8 and
as a result there is a detachable fixing, so that the hose elements
6 can be released or detached from the connecting elements 7, 8
again, e.g. for pressure monitoring or refilling. In the
construction according to FIG. 2 the hose elements 6 can in each
case be individually filled and optionally also with a different
pressure. An advantage is that in the case of the failure of one
hose the system can still function. However effort and expenditure
are higher for individual filling. In the construction of FIG. 3 a
common filling takes place via a connector 6.8, a common inlet 6.7
and the connection 6.6.
[0015] The hose elements 6 are under an internal pressure and for
this purpose filled with a gas. As a result of the overpressure in
the interior of the hose elements they widen radially and become
shorter, as illustrated by the continuous lines in FIG. 2. If a
tension is exerted on hose elements 6, if e.g. the rocker is moved
out of the vertical position shown in FIG. 1 into a position
inclined to a differing extent to the horizontal, there is a
reduction to the diameter of the central area of the hose element
6, as illustrated in broken line form in FIG. 2.
[0016] The invention gives rise to a low-maintenance and also
low-wear weight compensation means, which has limited space
requirements and low weight in the case of high flexibility with
respect to the possible uses, because the filling pressure and
length of the hose elements can be differently adjusted.
* * * * *