Belt-finishing device and method for operating a belt-finishing device

Abstract

A belt-finishing device including a frame. A pressing arm is configured to pivotally mount on the frame. A pressing element, which is used to press a finishing belt against a workpiece surface to be treated, is arranged on the pressing arm. The device is provided with a position detection system for detecting a pressing-arm actual position that deviates from a desired position of the pressing arm. A malfunction or defect of the pressing element is detected by means of the pressing arm actual position that deviates from the desired position of the pressing arm.

Claims

1. A belt finishing device comprising: a frame; a pressing arm mounted to the frame; a pressing element arranged on the pressing arm; a finishing belt disposed on the pressing element and configured to press against a workpiece surface to be treated; and a position detection apparatus configured to detect an actual position of the pressing arm that deviates from a desired position of the pressing arm.

2. The belt finishing device according to claim 1, wherein the desired position corresponds to an intact pressing element and the actual position corresponds to a missing or defective pressing element.

3. The belt finishing device according to claim 1, wherein a pressing force is applied to the pressing arm by a force application apparatus.

4. The belt finishing device according to claim 1, wherein the position detection apparatus is a displacement or angle measurement apparatus.

5. The belt finishing device according to claim 1, wherein the position detection apparatus is a distance measurement apparatus.

6. The belt finishing device according to claim 1, wherein the position detection apparatus comprises a first sensor part fixed to the frame and a second sensor part connected to the pressing arm.

7. The belt finishing device according to claim 1, wherein the pressing element is produced from a metal material.

8. The belt finishing device according to claim 1, wherein the pressing element is a pressing belt configured to press the finishing belt against a partial circumference of the workpiece surface to be treated.

9. The belt finishing device according to claim 1, wherein a pressing surface of the pressing element interacting with a reverse side of the finishing belt has one or both of a friction-enhancing surface structure and a friction-enhancing coating.

10. A method of operating the belt finishing device according to claim 1, comprising: detecting when the pressing element is missing or defective by detecting when the actual position of the pressing arm has deviated from the desired position of the pressing arm.

11. The belt finishing device according to claim 7, wherein the pressing element is spring steel.

12. The belt finishing device according to claim 1, wherein the pressing arm is pivotally mounted to the frame.

13. A belt finishing device comprising: a frame; a pressing arm mounted to the frame; a pressing element arranged on the pressing arm; a finishing belt disposed on the pressing element and configured to press against a workpiece surface to be treated; and a position detection apparatus configured to detect an actual position of the pressing arm that deviates from a desired position of the pressing arm, wherein the position detection apparatus comprises a first sensor part fixed to the frame and a second sensor part connected to the pressing arm, and wherein one of the sensor parts has a curved surface with varying radii of curvature and the other sensor part detects varying distances between the sensor parts over the course of a movement of the pressing arm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:

(2) FIG. 1 is a side view of a belt finishing device in a state preparing for work, including a pressing arm and a pressing element.

(3) FIG. 2 is a side view according to the view in FIG. 1 of the belt finishing device in an operating state in which a workpiece is being finished, the pressing element being intact and the pressing arm assuming a desired position, and

(4) FIG. 3 is a view according to FIG. 2, the pressing arm assuming an actual position that deviates from the desired position after the pressing element has broken.

DETAILED DESCRIPTION

(5) An embodiment shown in the drawings of a belt finishing device is denoted as a whole with the reference numeral 10. The device 10 has a frame 12, which is used to pivotally mount two pressing arms 14 and 16 about respective pivot axes 18, 20. The frame 12 is movably arranged on a stationary machine frame, or the frame 12 is an immovable component of a stationary machine frame.

(6) The pressing arms 14 and 16 each have a free end 22, 24, on each of which a pressing apparatus 26, 28 is arranged. The pressing apparatuses 26, 28 are provided with pressing elements 29. The pressing apparatus 26 has a pressing element 29 in the form of a curved, flexible pressing belt 30. The pressing belt 30 is preferably supported at two support points 32, 34 spaced apart from one another and fixed to the pressing apparatus 26 at its belt ends facing away from one another.

(7) The pressing element 29 of the pressing apparatus 28 is, for example, V-shaped and has two pressing portions at angles to one another.

(8) The pressing elements 29 of the pressing apparatuses 26, 28 are used to apply a pressing force to a reverse side of a finishing belt 36 facing the pressing apparatuses 26, 28 in order to press a front side of the finishing belt 36 facing a workpiece 38 against a workpiece surface 40 to be treated of the workpiece 38, cf. FIG. 1 and FIG. 2. In the process, it is possible for a pressing surface 42 of a pressing element, for example a pressing belt 30, interacting with the reverse side of the finishing belt 36 to have a friction-enhancing surface structure and/or a friction-enhancing coating, in particular diamond particles.

(9) It is understood that the pressing apparatuses 26, 28 can also be designed to be identical to one another or that the pressing apparatus 26 shown in the drawings can also be arranged in its installed position above the pressing apparatus 28 shown in the drawings.

(10) To generate a pressing force acting on the finishing belt 36 and therefore on the workpiece surface 40, a force application apparatus 44 is provided. The force application apparatus comprises, for example, a cylinder 46 and a piston 48 that is arranged movably inside the cylinder 46. The cylinder 46 is connected by its base 50 by a pivot bearing 52 to a lever 54 of the pressing arm 16. The free piston end 56 of the piston 48 is connected to a lever 60 of the pressing arm 14 via a pivot bearing 58.

(11) To detect the pivot position of the pressing arm 14 about the pivot axis 18, a position detection apparatus 62 is provided. The position detection device 62 comprises a first sensor part 64 fixed to the frame in the form of a distance sensor and a second sensor part 66 which is rigidly connected to the pressing arm 14 and is pivoted together with the pressing arm 14 about the pivot axis 18 when the pressing arm 14 is pivoted.

(12) The second sensor part 66 has a curved surface 68 that faces the first sensor part 64 and has different radii of curvature such that a distance measured between different portions of the curved surface 68 and the first sensor part 64 varies depending on the pivot position of the pressing arm 14 about the pivot axis 18.

(13) In a state preparing for work, the tong-like pressing arms 14 and 16 are opened such that the workpiece surface 40 to be treated, for example the circumferential bearing surface of a main crankshaft bearing or a crankshaft large end bearing, can be positioned freely relative to the pressing apparatuses 26, 28. In this work preparation state, the piston 48 is at least largely fully retracted into the cylinder 46, cf. FIG. 1. Starting from here, pneumatically or hydraulically generated extension of the piston 48 out of the cylinder 46 causes closure of the tong-like pressing arms 14 and 16 such that the pressing apparatuses 26 and 28 are each moved toward the workpiece surface 40 to be treated until the finishing belt 36 ultimately has a force applied to it by the pressing apparatuses 26 and 28 and is pressed against the workpiece surface 40 to be treated, cf. FIG. 2.

(14) In the region of the pressing belt 30, the finishing belt 36 is pressed across a partial circumference against the workpiece surface 40 to be treated. This partial circumference is indicated in FIG. 2 by dashed lines at angles to one another and by a double-headed arrow. The winding angle assigned to this partial circumference is, for example, between at least approximately 5 and at most approximately 180.

(15) During the finishing of the workpiece 38, said workpiece rotates about a workpiece axis 69. A rotary drive, which is known per se and is therefore not shown in the drawings, is provided for this purpose. An oscillating movement is superimposed on the rotary movement of the workpiece 38, and specifically in the form of a periodic movement of the workpiece to and fro in a direction parallel to the workpiece axis 69 (i.e. perpendicular to the drawing plane of FIGS. 1 to 3).

(16) In order to allow the pressing belt 30 to be able to cling as flexibly as possible to the workpiece surface 40 to be treated of workpieces 38 having different diameters from one another, the pressing belt 30 has a comparatively low belt thickness of, for example, at most 1 mm. Therefore, the pressing belt 30 has a curvature adjusted depending on a diameter of a workpiece surface to be treated.

(17) In particular when the pressing surface 42 of the pressing belt 30 has a friction-enhancing surface structure (for example a roughening) and/or a friction-enhancing coating (for example diamond particles), increased frictional forces act between the pressing surface 42 and the reverse of the finishing belt 36 and are oriented according to the oscillation movement in parallel with the workpiece axis 69 and in opposite directions to one another. These frictional forces can lead to the pressing belt 30 breaking or tearing such that the pressing belt 30 cannot transfer any pressing force onto the finishing belt 36 anymore.

(18) In FIG. 3, the pressing belt 30 is shown in a broken or torn state in which the pressing belt 30 has two pressing belt portions 30a and 30b separated from one another. Starting from the state shown in FIG. 2, in which the pressing arm 14 assumes a desired position, i.e. the pressing belt 30 is not broken or torn, a break or tear of the pressing belt 30 leads to the force application apparatus 44, in particular its piston 48, pivoting the pressing arm 14 about the pivot axis 18 such that the pressing apparatus 26 moves further toward the workpiece axis 69 of the workpiece 38 (cf. FIG. 3). In this state, the pressing arm 14 assumes an actual position, which deviates from the desired position when the pressing belt 30 is intact.

(19) This deviation of the actual position of the pressing arm from a desired position can be detected by a position detection apparatus 62 since the distance between the first sensor part 64 and the respective portions of the curved surface 68 of the second sensor part 66 changes over the course of the movement of the pressing arm 14.

(20) Advantageously, the position detection apparatus 62 is coupled to a controller of the belt finishing device 10 such that the detection of the transfer of the pressing arm 14 out of the desired position into a deviating actual position is accompanied by the generation of a warning signal and/or with an end to the finishing treatment of the workpiece 38.

(21) At a realistic scale shown in the drawings, the change of the pivot angle of the pressing arm 14 from the desired position into the deviating actual position can be relatively small. When using a force application apparatus 44, the stroke of the piston 48 accompanying such a pivoting of the pressing arm 14 is thus likewise comparatively small. Comparing FIG. 2 and FIG. 3, it can be seen that the displacement of the piston 48 when the pressing arm 14 is pivoted out of the desired position into the deviating actual position is accompanied by a correspondingly slight displacement of the pivot bearing 58 relative to the frame 12.

(22) Additionally or alternatively to the position detection apparatus 62 described above, it is also possible to detect the stroke of the piston 48 relative to the cylinder 46, in particular using a displacement measuring system.

(23) In an alternative embodiment, the pressing arms 14, 16 are not pivotally mounted, but can move along a linear movement path. In this case, it is proposed with respect to the position detection apparatus 62 that the second sensor part 66 does not have a curved surface 68 but rather a straight plane inclined relative to the movement axis of the pressing arm 14 such that a distance between different portions of the plane and the first sensor part 64 fixed to the frame changes over the course of a movement of the pressing arm 14.

(24) The invention has been described above with reference to the pressing element 29 in the form of a pressing belt 30; it is, however, understood that a position detection apparatus 62 can, additionally or alternatively, also be provided on the pressing arm 16 in order to be able to detect a failure, in particular a breakage, of the prismatic pressing element 29 of the pressing apparatus 28.

(25) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments.

(26) The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article a or the in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of or should be interpreted as being inclusive, such that the recitation of A or B is not exclusive of A and B, unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of at least one of A, B and C should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of A, B and/or C or at least one of A, B or C should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.