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.

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° 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.

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°.

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.