Machine for working sheet metal parts

Abstract

A machine for processing sheet metal parts has a machine frame (20), a conveyor belt (30) for transporting the sheet metal part (10) to be processed in a horizontal direction, and a plurality of processing units arranged one behind the other along the conveyor belt (30), comprising a brush unit (70) with abrasive brushes (71), a first abrasive belt unit (40), and a second abrasive belt unit (80). The abrasive belt units (40, 80) are mounted in auxiliary frames (50, 90) which are movable in the vertical direction relative to the machine frame (20). Adjustment devices are arranged between the machine frame (20) and the auxiliary frames (50, 90). The brush unit (70) is also mounted so that it can be moved in the vertical direction, allowing the different processing units to be adjusted independently of one another to enable the staged processing of workpieces in a single pass.

Description

[0001] The present invention relates to a machine for processing sheet metal parts in several successive processing steps, in particular deburring, rounding of edges and grinding of the surface.

[0002] When cutting and punching parts from sheet steel, disruptive burrs form on the cut edges and the edges of holes and recesses, protruding from the top surface. Particularly with workpieces made from sheet steel several centimeters thick, considerable technical effort is required to deburr these burrs, round the edges, and finally grind the surface flat.

[0003] EP 3 085 491 A1 describes a machine for grinding and deburring a flat tool workpiece with a horizontal grinding roller. Such a machine can grind the surface, but cannot round edges or remove deeper burrs.

[0004] EP 2 792 450 describes a deburring machine with horizontally rotating belts carrying a multitude of brushes arranged side by side. The brushes consist of a fan-shaped pack of abrasive paper or abrasive fleece. The sheet metal part to be deburred is fed forward perpendicular to the direction of movement of the brushes. The edges of the abrasive paper or fleece rub across the surface of the workpiece perpendicular to the feed direction, thereby removing the protruding burrs. Due to the flexibility of the brushes, they can penetrate recesses to a certain extent.

[0005] EP 1 293 292 A1 describes a machine for machining workpieces with a round grinding disc that rotates around a vertical axis. The grinding disc has radial brushes on its underside that brush against the workpieces.

[0006] DE 10 2018 126 281 A1 describes a grinding device for machining a metal workpiece in a continuous process, comprising a height-adjustable wide-belt grinding unit and another grinding unit with disc sanders for producing a finish on a surface of the workpiece. A transport device moves the workpiece linearly under the wide-belt grinding unit and under the other grinding unit.

[0007] DE 21 2017 000 255 U1 discloses and describes a deburring machine with a central brush unit and a subsequent abrasive belt unit arranged in the direction of travel. The brush grinding head has brush rollers that are mounted horizontally. The position of the brush unit is adjustable in the vertical direction to set and adapt the processing of workpieces of different thicknesses or to compensate for wear of the brush rollers. The additional abrasive belt unit is not height-adjustable.

[0008] CN 211465850 U discloses a deburring machine with three processing stations arranged in series, namely two brush grinders with vertically rotating discs and a grinding belt unit as the third processing station. The grinding belt unit is not adjustable in the vertical direction.

[0009] EP 1 062 072 B1 discloses a method for operating a wide grinding machine for producing a high-quality ground surface on flat objects that are continuously transported through the machine. The wide grinding machine comprises two or more grinding units arranged one behind the other. In the machine shown in Figure 3a, two fine grinding belts are used, positioned in front of and behind a centrally located grinding roller. The grinding units are positioned at a slight angle of engagement relative to the feed direction of the objects, such that a rhombus pattern is produced in the first fine grinding stage, and this rhombus-shaped rough pattern is then ground over in the subsequent fine grinding stage. The contact pressure in the fine grinding stage is adjustable or controllable. Grinding belts, fine grinding rollers, or fine grinding brushes can be used as abrasives.

[0010] Grinding and deburring machines must be precisely adjusted to the thickness of the sheet metal parts being processed. This ensures that the processing tools exert sufficient pressure on the workpiece while simultaneously preventing damage to the tools and preventing the workpiece from getting stuck or jammed. Adjusting a brush unit with grinding brushes is somewhat less critical because the brushes are flexible and can deflect from the workpiece to a certain extent. However, with a belt grinding unit featuring a contact roller positioned transversely to the direction of travel, the distance between the conveyor belt and the contact roller, as well as the feed rates, must be set very precisely. This ensures that the workpiece can still move under the rotating contact roller while simultaneously allowing the grinding belt to apply sufficient pressure across the workpiece surface.

[0011] In a machine with linked processing units, where a number of processing units are arranged one after the other along a continuous conveyor belt in the direction of travel of the workpiece, the particular challenge lies in setting all processing units as simply as possible, yet precisely, to the thickness of the sheet metal part to be processed.

[0012] The object of the invention is the design of a machine for processing sheet metal parts with a conveyor belt for transporting the workpiece to be processed in a horizontal direction from a feed table to an output table and a plurality of processing units which are arranged one behind the other along the conveyor belt and which comprise a brush unit with grinding brushes and at least one grinding belt unit which can be quickly and optimally adjusted to different thicknesses of the sheet metal parts to be processed.

[0013] This technical problem is solved by a machine having the features of the first patent claim.

[0014] In the machine according to the invention, three processing units are arranged one after the other along the conveyor belt: firstly, a first grinding belt unit in a first auxiliary frame; secondly, a central brush unit with grinding brushes; and thirdly, a second grinding belt unit in a second auxiliary frame behind the central brush unit. With such an arrangement and combination of processing units, workpieces can be processed in stages in a single pass.

[0015] The arrangement of the grinding belt units on a vertically movable auxiliary frame enables quick, easy, and very precise adjustment of the distance between the conveyor belt and the contact roller, i.e., the feed rate. The workpiece feed height, which is determined by the vertical height of the conveyor belt in the machine frame, serves as the reference height for all processing units. This has the advantage that the vertical height of the conveyor belt can first be set, for example, to adapt to upstream or downstream workstations in a machine chain, and then the working gaps of the various processing units can be adjusted independently.Due to the combination of brush unit with grinding brushes and grinding belt unit with horizontal contact roller, the machine according to the invention can, in particular, rework punched or cut sheet metal parts with a thickness of up to several centimeters with excellent results by deburring and / or rounding the edges and margins as well as grinding the surface.

[0016] The first abrasive belt unit has a coarse-grit belt for deburring, and the second abrasive belt unit has a fine-grit belt for grinding the workpiece surface. The central brush unit in the middle is primarily used for rounding edges on the recesses in the surface of the sheet metal part. An abrasive belt unit with a contact roller can only deburr the leading edge of a sheet metal part, whereas the flexible abrasive brushes of the brush unit penetrate a certain distance into the recesses of the sheet metal part.

[0017] The dependent claims contain further advantageous and expedient embodiments of the machine according to the invention.

[0018] An embodiment of the invention is explained below with reference to the figures. They show: Figure 1: A machine for processing sheet metal parts, in a schematic side view; Figure 2: The machine of Figur 1 , from the front.

[0019] The machine is used to process relatively thick sheet metal parts 10 in three successive processing steps, namely deburring, rounding the edges and grinding the surface.

[0020] A machine frame 20 essentially comprises front and rear vertical beams 21a, 21b and intermediate horizontal beams 22. In the area of ​​the lower horizontal beams 22b, four parallel vertical guides 23a, 23b are arranged.

[0021] A conveyor belt 30 is mounted at a distance from the floor within the machine frame 20. The conveyor belt 30 comprises a working section 31 and an idle section 32 and runs between a deflection roller 33a and a drive roller 33b, which extend transversely to the direction of transport. The conveyor belt 30 extends beyond the machine frame 20 at the machine inlet and outlet. The sections of the conveyor belt 30 extending beyond the machine frame 20 form a loading area 34 and an unloading area 35. The sheet metal part 10 to be processed is continuously transported in the direction of the arrow from the loading area 34 to the unloading area 35, passing through three different processing units in succession.

[0022] The first processing unit is a first grinding belt unit 40 with a coarse-grained grinding belt 41, which is endless and runs between a contact roller 42 and a deflection roller 43. The contact roller 42 has a pulley 44, which is driven by an electric motor 45 via a drive belt 46. The deflection roller 43 is rotatably mounted on a bearing fork 47.

[0023] The first grinding belt unit 40 is completely integrated into a first subframe 50. The subframe 50 comprises two parallel vertical rails 51a, 51b spaced apart from each other and a crossbeam 52 connecting them (see figure). Fig. 2 The auxiliary frame 50 has a cross-section that essentially corresponds to an inverted U, with the vertical rails 51a, 51b forming the legs of the U and the crossbeam 52 forming the back of the U. The vertical rails 51a, 51b run laterally in a space between the machine frame 20 and the conveyor belt 30.

[0024] The vertical rails 51a, 51b each have a cross-section in the shape of a flat, large U, with the backs of the U facing each other. The pulley 44 and the drive belt 46 are arranged within the U-shaped cross-section of the vertical rail 51a, while the electric motor 45 is located on the outside to save space (see figure). Fig. 2 ).

[0025] The vertical rails 51a, 51b of the first subframe 50 are slidably mounted in the vertical guides 23a, 23b of the machine frame 20.

[0026] A clamping cylinder 53 is located between the bearing fork 47 of the grinding belt unit 40 and the cross member 52 of the subframe 50. A clamping device 48 with a manually operated clamping lever allows the cross member 52 to be clamped onto the subframe 50. The clamping device 48 is released to change the grinding belt 41. In doing so, the tension between the contact roller 42 and the deflection roller 43 is released by the clamping cylinder 53. The grinding belt 41 can then be moved parallel to the contact roller 42 (in Fig. 2 to the left) can be pulled out.

[0027] The auxiliary frame 50 of the first grinding belt unit 40 includes an adjusting device, which is exemplified here as a lifting spindle drive 60. This allows the distance between the conveyor belt 30 and the contact roller 42 of the grinding belt unit 40, or the feed rate, to be set very precisely and, if necessary, quickly adjusted, with the auxiliary frame 50 being moved vertically upwards or downwards on the vertical guides 23a, 23b.

[0028] The second processing unit is a brush unit 70, which is arranged behind the first grinding belt unit 40 in the direction of travel of the sheet metal part 10.

[0029] The brush unit 70 has a total of eight grinding brushes 71, four of which rotate in the same direction and four in the opposite direction around horizontal axes. Fig. 1 Only the front row with four grinding brushes 71 is visible.

[0030] An electric drive unit 72 drives the grinding brushes 71 via a distribution gearbox 73. While the drive unit 72 is fixed in the machine frame 20, the distribution gearbox 73 is rotatable about its vertical axis. This results in a multi-rotational movement of the grinding brushes 71. The grinding brushes 71 consist of a multitude of flexible abrasive flaps, the ends of which brush over the surface of the sheet metal part 10 passed under the grinding brushes 71 and can also penetrate a portion of the recesses. At the same time, both the front and side edges of the sheet metal part 10 are rounded.

[0031] The brush unit 70 has a height adjustment device arranged between the drive unit 72 and the machine frame 20, which is implemented here by way of example as a lifting spindle drive 74a, 74b. This allows the machining gap or the feed, i.e. the distance between the grinding brushes 71 and the working face 31 of the conveyor belt 30, to be set very precisely.

[0032] The third processing unit is a second abrasive belt unit 80, which is arranged behind the central brush unit 70 in the direction of travel of the sheet metal part 10. Unlike the first abrasive belt unit 40, the second abrasive belt unit 80 has a fine-grained abrasive belt 81, which is endless and runs between a contact roller 82 and a deflection roller 83. The second abrasive belt unit 80 is driven in the same way as the first abrasive belt unit 40 by means of an electric motor, which drives the contact roller 82 via a drive belt and a pulley (see figure). Fig. 2 ).

[0033] The entire second sanding belt unit 80 is mounted on a second subframe 90, which in principle corresponds to the first subframe 50 for the first sanding belt unit 40 (see figure). Fig. 2 An adjusting device, designed as a lifting spindle drive 100, is also arranged between the machine frame 20 and the second grinding belt unit 80. This allows the distance between the conveyor belt 30 and the contact roller 32 of the second grinding belt unit 80, or the feed rate, to be finely adjusted by moving the auxiliary frame 90 vertically upwards or downwards on the vertical guides 24a, 24b of the machine frame 20.

[0034] The second grinding belt unit 80 with fine-grained grinding belt 81 is used for fine grinding of the top surface of the sheet metal part 10. The result is a cleanly deburred workpiece with rounded edges and a finely ground surface. Reference sign

[0035] 10 sheet metal parts 20 Machine frame 21a, 21b Vertical beams 22a, 22b Horizontal beams 23a, 23b Vertical guides 24a, 24b Vertical guides 30 Conveyor belt 31 Working side 32 Easier side 33a Deflection roller 33b Drive roller 34 Loading area 35 Unloading area 40 First grinding belt unit 41 Grinding belt 42 Contact roller 43 Deflection roller 44 Pulley 45 Electric motor 46 Drive belt 47 Bearing fork 48 Tensioning device 50th subframe (for 40) 51a, 51b Vertical rails 52 Crossbeam 53 Tension cylinder 60 Lifting spindle gearbox (for 40) 70 Brush unit 71 Grinding brushes 72 Drive unit 73 Distribution gearbox 74a, 74b Lifting spindle gearbox (for 70) 80 Second abrasive belt unit 81 Abrasive belt 82 Contact roller 83 Deflection roller 90 Second subframe (for 80) 100 lifting spindle gearboxes (for 80)

Claims

1. Machine for processing sheet-metal parts in several successive processing steps, in particular deburring, edge rounding and surface grinding, comprising a machine frame (20); a conveyor belt (30) for conveying the sheet-metal part (10) to be processed in a horizontal direction from a feed table (34) to a discharge table (35); a plurality of different processing units which are arranged one after another along the conveyor belt (30) in the direction of through-feed of the sheet-metal part (10) and comprise a brush unit (70) with flexible abrasive brushes (71) and two abrasive belt units (40, 80), each having a contact roller (42, 82) arranged transversely to the direction of through-feed; wherein the brush unit (70) is arranged approximately in the center of the machine frame (20); a first abrasive belt unit (40) is arranged in a first auxiliary frame (50) upstream of the central brush unit in the direction of through-feed; and a second abrasive belt unit (80) is arranged in a second auxiliary frame (90) downstream of the central brush unit in the direction of through-feed; the auxiliary frames (50, 90) are mounted in the machine frame (20) so as to be vertically movable in order to adjust the distance between the conveyor belt (30) and the contact rollers (42, 82) of the abrasive belt units (40, 80); in each case, an adjusting device for adjusting the distance between the conveyor belt (30) and the contact rollers (42, 82) of the abrasive belt units (40, 80), independently of the other processing stations, is arranged between the machine frame (20) and the auxiliary frames (50, 90); the first abrasive belt unit (40) has a coarse-grained abrasive belt (41) for deburring, and the second abrasive belt unit (80) has a fine-grained abrasive belt (81) for grinding the surface of the sheet-metal part (10).

2. Machine according to claim 1, characterized in that the auxiliary frames (50, 90) have a cross-section which substantially corresponds to an inverted U, the U-legs extending in an intermediate space between the conveyor belt (30) and the machine frame (20).

3. Machine according to one of the preceding claims, characterized in that the auxiliary frames (50, 90) have two parallel vertical rails (51a, 51b) which are slidably mounted in vertical guides (23a, 23b; 24a, 24b) of the machine frame (20).

4. Machine according to one of the preceding claims, characterized in that the adjusting devices each comprise a lifting spindle gear (60, 100).

5. Machine according to one of the preceding claims, characterized in that the brush unit (70) has a plurality of cylindrical abrasive brushes (71) rotating about horizontal axes.

6. Machine according to one of the preceding claims, characterized in that the brush unit (70) is mounted suspended in the machine frame (20) in such a manner that the abrasive brushes (71) float above the conveyor belt (30) at a predetermined distance.

7. Machine according to one of the preceding claims, characterized by a height-adjusting device arranged between the machine frame (20) and the brush unit (70) for adjusting the distance between the conveyor belt (30) and the abrasive brushes (71).

8. Machine according to claim 7, characterized in that the height-adjusting device comprises a lifting spindle gear (74a, 74b).

Images