Patent ID: 12205427

DETAILED DESCRIPTION

FIG.1shows a sectional view of a compensating element10according to the disclosure. The corresponding section plane contains the midaxis11, which extends through the center of a ball61. The compensating element10comprises a first and a second module20;40, which in the first operating state represented inFIG.1are secured to one another. In the second operating state, the first and the second module20;40are movable relative to one another, a variable gap between the first and the second module20;40being covered by an annular bellows12.

The first module20, on the top inFIG.1, comprises a first and a second housing body21;22, each of which is configured in the shape of a cup with respect to the midaxis11. Their open sides face toward one another so that together they delimit a cavity26.

The first housing body21comprises an annular first main part23, which forms a section of the outer circumferential face of the first module20. The first module20furthermore comprises a first fastening flange25which is firmly connected to the first main part23by means of a plurality of screws36that are arranged obliquely with respect to the midaxis11and forms the bottom of the aforementioned cup shape. The compensating element10is preferably produced in a plurality of variants which differ in respect of the shape of the first and/or second fastening flange25;43, so that the compensating element may be used for different robots and different grippers.

The second housing body22comprises an annular second main part24and a second plate28. The second main part24forms a section of the outer circumferential face of the first module20. The second plate28forms the bottom of the aforementioned cup shape.

A first ring81, the outer circumferential face of which forms a luminous surface80, is received in the direction of the midaxis11between the first and the second main part23;24. The first ring81extends with a constant rectangular cross-sectional shape circularly around the midaxis11. It preferably consists of a light-scattering polycarbonate. On its two end sides facing in the direction of the midaxis11, a sealing ring84is respectively arranged toward the first and second main part23;24, respectively.

The first ring81encloses a first plate27, which is arranged statically inside the first module20. An electric motor51, which comprises gearing, is firmly connected to the first plate27, its drive spigot52extending through the first plate. The rotation axis53of the electric motor51coincides with the midaxis11of the compensating element. Because of the gearing, the rotation axis53of the electric motor51is arranged somewhat off-center on the electric motor51itself. The drive spigot52is already mounted rotatably inside the electric motor51, and it is additionally provided with a further radial rolling bearing54that is received in the first plate27. In this way, the forces acting on the second ring62are intended to be supported optimally. The second ring62is provided integrally with a hub55, which is firmly connected to the drive spigot52(cf. threaded pin56inFIG.2). In the direction of the midaxis11, the second ring62is supported directly on the first plate27.

The electric motor51is enclosed by an annular second circuit board32. The second circuit board32carries a plurality of luminous means90, which are arranged uniformly distributed around the midaxis11. Each luminous means90is configured in the form of an LED which can emit in a plurality of colors. The number of luminous means90is selected to be so large that, when all the luminous means90are shining with equal strength and with the same color, the impression of a continuous color ring is obtained on the luminous surface81. In this case, the light-scattering effect of the first ring81is utilized.

Furthermore, the second circuit board32carries a controller or driver, with which current can be applied to the electric motor51. The second circuit board32can be connected by means of the electrical terminal13on the first base body21to a control, all functions of the compensating element10being drivable by means of this connection. The current supply of the compensating element10also takes place via the terminal13.

A first circuit board31is furthermore provided, which is arranged on the opposite side of the first plate27with respect to the second circuit board32, that is to say inside the second housing body22. The first circuit board31carries the electronic components of the measuring system70, with which the relative position between the first and the second module can be measured. The measuring system70is configured according to DE 10 2015 219 332 A1. The entire content of DE 10 2015 219 332 A1 is referenced and included in the content of the present application. The measuring system70comprises in total six optical distance meters72, which are respectively carried by the first circuit board31. The distance meters72are combined into three pairs, the three pairs being arranged distributed as an angular spacing of 120° around the midaxis11. Each aforementioned pair is assigned a prism71, these respectively being formed in the present case integrally with the second fastening flange43. Each prism71forms two plane measuring faces (No.73inFIG.2), which are arranged inclined by 90° with respect to one another. Each distance meter72is assigned a measuring face, in the zero position of the compensating element10its measuring direction being aligned perpendicularly to the assigned measuring face and centrally with respect thereto. By means of the six measured distance values, the relative position between the first and the second module can be calculated in six degrees of freedom. To this end, a nonlinear system of equations needs to be solved, which is preferably done with a gradient descent method. The corresponding computer in the form of a microcontroller is preferably received on the first circuit board31.

The first circuit board31is connected by means of electrical lines33to the second circuit board32. The first and the second circuit board31;32are respectively received statically inside the first module20. In the region of the balls61, the first circuit board31is provided with openings.

The locking mechanism60in the present case comprises three balls61, which are arranged uniformly distributed around the midaxis11. Parallel to the midaxis11, each ball61is guided movably by means of a guide ring29. The guide ring29consists of steel, it being pressed into a matched recess in the second main part24, which consists of aluminum. In the axial direction, the position of the guide ring29is secured with a form fit. The separate guide ring29in this case prevents the wear which would occur if the balls61were guided directly on the second main part24.

InFIG.1top, that is to say toward the first plate27, each ball bears on the second and on the third ring62;63. The second and the third ring62;63are arranged concentrically with respect to the midaxis11, the second ring62being arranged inside the third ring63so that the second and the third ring62;63directly touch a ball61at different locations.

The third ring63extends with a constant rectangular cross-sectional shape around the midaxis11. It is supported by three springs64on the first plate27. The springs64are configured as helical compression springs, these being arranged uniformly distributed around the midaxis11. The springs64are received at both ends in matched recesses of the third ring63or of the second plate28, respectively. They are in this case arranged in the direction of the midaxis11approximately flush with an assigned ball61.

The second ring62bears with a plane face directly on a plane surface of the first plate27in such a way that it can move by sliding. In the direction of the midaxis11, it has a thickness which changes over the circumference of the second ring62in three periods between a minimum and a maximum. When the three thickness maxima bear on the balls61, the first operating state is set up, the compensating element being locked. When the three thickness minima are arranged in the region of the balls61, the second operating state is set up. The switching between the two operating states is carried out by rotating the second ring62by means of the electric motor51.

The balls61lie on an assigned ball seat41in the shape of a circular cone, regardless of which operating state the compensating element10is in. The ball seat41is firmly connected, in particular screwed, to the second fastening flange43by means of an integral arm42. The arm42in this case extends through a bore37in the second plate28, the ball seat41bearing with a dampening ring44at the edge of the bore37on the second plate28when the compensating element10is in the first operating state, or the zero position. In the second operating state, this contact may be eliminated by applying a force to the second fastening flange43. Depending on the direction of this force, at least one ball61moves against the force of the respectively assigned spring64toward the first plate27. In the second operating state, the second module40is thus resiliently supported on the first module20. When an external force is not applied to the second module40, the spring forces in cooperation with the guide rings29have the effect that the second module40springs back into a defined zero position. In this zero position, it may be firmly clamped by the second ring62in order to set up the first operating state.

FIG.2shows a further sectional view of the compensating element10according toFIG.1. The section plane likewise contains the midaxis11, it being rotated through 90° relative toFIG.1. Consequently, all three balls61are arranged outside the section plane.

InFIG.2, the way in which the various parts of the first module20are screwed together may be seen. To this end, the screw34and the assigned bolt35are used, three of each of which are respectively present, the corresponding pairs being arranged uniformly distributed over the circumference of the compensating element10. The bolt35that is parallel to the midaxis11is screwed with a male thread into the second plate28. It extends through the first plate27with a cylindrical mating surface, so that the first plate27is accurately aligned. The screw34parallel to the midaxis11extends through the first main part23, it being screwed into a female thread of the bolt35. In this way, the first main part23is braced against the first plate27. The first plate27bears via at least one spacer plate38on the second main part24, the latter in turn bearing directly on the second plate28so that the flow of force of the screw34is closed. In order that the corresponding clamping force is transmitted only to a small extent via the first ring81, the latter is held between two sealing rings84, and it bears with its luminous face80section-wise internally on the first and second main part23;24, respectively.

FIG.2furthermore shows the firm connection between the second ring62and the drive spigot52. Screwed into the hub55of the second ring62transversely with respect to the midaxis11, there is a threaded pin56, the latter being clamped against a flat area on the drive spigot52.

FIG.2furthermore shows a prism71in a side view. The two corresponding plane measuring faces73are accordingly aligned perpendicularly to the section plane ofFIG.2. They intersect on an imaginary straight line, which in turn intersects the midaxis11at a right angle. Considered in the direction of view ofFIG.2, the two measuring faces73assigned to one another are arranged mirror-symmetrically with respect to the midaxis11.

FIG.3shows a rough schematic plan view of the luminous means90. The direction of view is directed parallel to the midaxis11from the first module onto the second module. The midaxis11defines a coordinate system14, the horizontal axis inFIG.3being the Y axis, the vertical axis inFIG.3being the X axis. The Z axis coincides with the midaxis11. In the zero position, Z=0. In a deflected setting, the spring mechanism explained above allows only positive values for Z.

In the present case, 36 luminous means90are arranged uniformly distributed around the midaxis11. This number was selected because it contains the prime factor 2 twice and the prime factor 3 twice. All the luminous means90are configured in the same way as one another, these being color LEDs. They can shine in different colors and with different luminosities.

A first display mode, with which the relative position between the first and the second module can be displayed, will be explained below. Four groups of luminous means90offset by 90°, which are respectively denoted by letters a, b, c, d, are indicated inFIG.3. Groups a and c are assigned to the X axis. The luminous means91a;91cin this case indicated a translation of the second module toward negative X values. The greater the corresponding displacement, the more the luminous means91a;91cshine. This principle is also referred to as a “bar graph display”. The luminous means92a;92csimilarly indicate a translation of the second module toward positive X values. The luminous means93b;93dsimilarly indicate a translation of the second module toward negative Y values. The luminous means94b;94dsimilarly indicate a translation of the second module toward positive Y values. In all cases explained above, the displayed axial direction coincides with the position of the assigned luminous means. The length of the bar graph preferably increases in the direction of the relevant translation.

The translation in the Z direction is indicated by the luminous means90a;90b;90c;90d. To this end, only two luminous means are respectively provided. Since this is too few for a bar graph display, the translation is displayed with color coding. Green corresponds to the translation zero, yellow corresponds for example to a displacement of 50% of the maximum Z travel. Red corresponds for example to a displacement of 100% of the maximum Z travel. The luminous means90used in this case allow a substantially continuous change of the displayed color, so that arbitrary intermediate values may also be displayed.

The luminous means99a;99b;99c;99dare not used in the first display mode, and preferably do not shine.

In the first display mode, only translations are displayed. In a second display mode, rotations about the X and Y axes can additionally be displayed. To this end, the bar graph display of the assigned translation axis is color-coded, in a similar way to the method explained for the Z translation.

In the first and second display modes, the display may relate to the zero position. It is, however, also conceivable for the display to be based on another zero point. This is expedient, for example, when the intention is to check whether a component complies with particular tolerances. The compensating element then carries a probe, for example on the second module, the first module of the compensating element being moved by means of a buckling-arm robot. The workpiece location to be tested is sampled with the probe, a setpoint deflection of the compensating element being set up. This then defines the zero point of the display. If the actual deflection of the compensating element deviates from the setpoint deflection, the corresponding luminous means90shine and thus display a tolerance deviation.

A third display mode signals that the compensating element has been connected to the voltage supply, the computer inside the compensating element being started up. To this end, any rigidly predetermined light pattern of the luminous means90may be used, which may if desired vary in the course of time.

A fourth display mode indicates a fault of the compensating element. To this end, for example, all the luminous means90shine red.

A fifth display mode indicates the relative position between the first and second modules in the manner of a spirit level. In this case, for example, only the two directly neighboring luminous means90which are assigned to the lowermost location of the second module shine.

In a sixth display mode, an operating status of the compensating element may be displayed. To this end, for example, particular luminous means90are assigned to particular sensors inside the compensating element. If the corresponding sensor is functional, the corresponding luminous means90shine green, if its function is faulty, the corresponding luminous means90shine red. The compensating element is thus functioning properly when all the LEDs90shine green.

REFERENCES

10compensating element11midaxis12bellows13electrical terminal14coordinate system20first module21first housing body22second housing body23first main part24second main part25first fastening flange26cavity27first plate28second plate29guide ring31first circuit board32second circuit board33electrical line34screw35bolt36screw37bore38spacer plate40second module41ball seat42arm43second fastening flange44dampening ring50locking mechanism51electric motor52drive spigot53rotation axis of the electric motor54radial rolling bearing55hub56threaded pin60spring mechanism61ball62second ring63third ring64spring70measuring system71prism72optical distance meter73measuring face80luminous surface81first ring82inner circumferential face of the first ring84sealing ring90luminous means90aluminous means Z90bluminous means Z90cluminous means Z90dluminous means Z91aluminous means X−91cluminous means X−92aluminous means X+92cluminous means X+93bluminous means Y−93dluminous means Y−94bluminous means Y+94dluminous means Y+99aunused luminous means99bunused luminous means99cunused luminous means99dunused luminous means