DE102016117993A1 - Device for determining a radius and grinding machine - Google Patents

Abstract

The present invention comprises a device (1) for determining a radius (20) of a contour of a workpiece having at least a circular segment-shaped cross section, wherein the device (1) - two contact surfaces (2) for applying the workpiece and - at least one caliper (4) in which - the abutment surfaces (2) are arranged at a right angle to one another and - the caliper (4) is displaceably arranged along an angle bisector of the right angle so that the caliper (4) is displaceable by moving the workpiece against the two abutment surfaces ( 2) is created.

Description

The invention relates to a device for determining a radius of a contour of an object with at least kreissegmentförmigem cross section and a grinding machine, which is equipped with such a device.

The determination of workpiece radii is important in a variety of industries and applications. For example, there are legal or other provisions that, for example, for safety-relevant components or components that are to be installed in the vicinity of persons, require that edges are rounded with a minimum radius in order to avoid injuries and reduce hazards. This is the case, for example, with plastic parts in the automotive industry and the automotive supplier industry but also in the case of metallic components whose edges have to be deburred and rounded. This is often done by using grinders that can remove burrs from metallic edges as well as round off the edges themselves. However, the problem is to determine after such a step, how large a radius of curvature of such a rounded edge is actually and he above, for example, already meets the legal or other requirements. The invention is therefore based on the object to develop and propose a device with which the radius of a contour of an object can be determined in a particularly simple manner, wherein the article has an at least circular segment-shaped or circular cross-section.

The invention solves this problem by a device for determining a radius of a contour of an object with at least kreissegmentförmigem cross section, the two contact surfaces for applying the object and at least one Messschiebeaufweis, wherein the contact surfaces are arranged at a right angle to each other and the caliper along an angle bisector right angle is slidably arranged such that the caliper is displaceable by the object is applied to the two contact surfaces. Advantageously, the device has a measuring device for measuring the distance by which the caliper is displaced when the object is applied to the two contact surfaces. In a particularly advantageous embodiment, the device has an electrical control which is set up to determine the radius from the measured distance. The device preferably has a display device which is set up to indicate the radius and / or the distance by which the caliper has been displaced.

The present invention is based on the finding that an object with a circular segment-shaped or circular cross-section, which is arranged with the contour of this cross section at the two arranged at a right angle bearing surface, the caliper shifts. The circle-segment-shaped or circular cross-section can be approximated, at least mentally, by a circle having a radius which is to be determined by the device. In this case, this circle forms the incircle or inner circle into a square whose one corner is formed by the point at which the two abutment surfaces abut each other. This square can be mentally described by a perimeter or outer circle, whose center is therefore located in the center of the Innkreises and passing through the contact point, so the "corner" of the two contact surfaces. The statements about circles, squares or points in each case relate to the cross section through the object which is inserted into the device according to an embodiment of the present invention.

The difference between the radius of the inscribed circle or inner circle and the radius of the circumference or outer circle corresponds exactly to the distance by which the caliper still protrudes from the corner formed by the two contact surfaces. If it is known how far the calliper protrudes from this corner without an inserted object, it is easy to calculate how big the difference between the radius of the inner circle and the radius of the outer circle is. In this way, the radius of the inner circle can be determined, which corresponds to the radius to be determined.

The invention also achieves the stated object by a grinding machine for grinding a surface of a workpiece, wherein the grinding machine has at least one grinding tool and is characterized in that the grinding machine has a device prescribed for this purpose. Advantageously, the device is arranged to determine the radius of an edge of the workpiece. This is advantageously done after the workpiece has run along the actual grinding tool and has interacted with it, thus after the grinding process. Due to the very simple device for measuring the radius can be determined in a particularly simple, yet safe and reproducible manner, whether the desired grinding result has been achieved and the radius of the edge of the workpiece meets the legal or other requirements. For this purpose, only the edge of the workpiece whose radius is to be measured, must be applied to the two contact surfaces of the device. About the way to the caliper in this Positioning is moved, the radius of the edge can be determined in a particularly simple manner.

Preferably, the grinding machine has an actuator that moves the device to the desired edge of the workpiece. This is advantageously done fully automatically, so that intervention by operating personnel is not necessary. For this purpose, it may be advantageous if the grinding machine has a position detection device and / or an orientation detection device with which the position and / or orientation of the workpiece can be recognized on a transport device of the grinding machine. In this way, an electrical control of the grinding machine can ensure that the actuator, which can be, for example, a robot arm, particularly preferably a multi-jointed robot arm, precisely approaches and applies the device to the desired location of the workpiece to be checked and the required edge.

Advantageously, a radius determined by the device is used as control parameter or controlled variable in the electrical control of the grinding machine. In particular, in the event that the certain radius does not meet the legal or other requirements or has too great a deviation from a predetermined target value, the workpiece can be performed, for example, again by the grinding machine or be marked as rejects or nacharbeitendes workpiece. In addition, it is possible, in particular in the event that the specific radius is too small, ie the abrasion caused by the grinding machine is insufficient to achieve the desired target value, to increase the contact pressure of the grinding tool to the surface of the workpiece and thus at the following Workpieces to achieve a larger grinding abrasion and thus a larger radius of the edge. This is particularly useful when several workpieces, especially many workpieces to be processed and ground one after the other, which have a surface made of the same material.

It has proven to be advantageous if the grinding machine has several such devices. In this way, different edges with possibly different target radii can be measured simultaneously and in this way the quality control can be accelerated.

Preferably, the grinding machine has a housing in which the grinding unit is arranged, wherein the conveyor belt is removable from the grinding machine, wherein the grinding unit and / or the grinding table does not have to be removed from the grinding machine.

Conventionally, the conveyor belt is not exposed to excessive loads, so that a change of the conveyor belt in the operation of a grinding machine is a rarely be performed maintenance action. Conventionally, the grinding table and possibly additionally the grinding unit, ie the actual abrasive, must be removed from the housing of the grinding machine. Then the grinding table has to be disassembled so far that the conveyor belt becomes accessible.

By this design of the grinding machine, it is now possible to change the conveyor belt and remove from the grinding machine without removing the grinding unit and / or the grinding table from the grinding machine. As a result, the change of the conveyor belt is greatly simplified. If, for example, metallic surfaces of different metals are to be ground in succession, instead of the often expensive and time-consuming cleaning of a conveyor belt, the respective grinding belt can now be exchanged so that particles of the grinding dust or grinding chips adhering to the grinding belt no longer have to be removed. For example, different conveyor belts can be provided for different metals, which can be used in the grinding machine depending on the desired type of metal that is to be ground. Alternatively, of course, a removed conveyor belt can be cleaned with the required care to be ready for later use with another type of metal. With the embodiment of the grinding machine according to the invention, this no longer has the consequence that during this time of cleaning the conveyor belt, it is no longer possible to grind workpieces. Rather, one of the conveyor belts can be cleaned while another conveyor belt is used in the grinding machine.

Preferably, the housing has an opening flap, which can be brought into an open state and a closed state, wherein the conveyor belt is accessible when the opening flap is in the open state. The opening flap is advantageously a door or a double door, which is arranged so that the housing can be opened easily. When the housing is open, ie when the opening flap is in the open state, the conveyor belt can be easily removed from the grinding machine. Advantageously, the grinding table is attached to at least one releasably mounted support. Especially with larger grinding machines or grinding modules, which optionally have more than one grinding unit, it is advantageous to secure the grinding table on both sides of the conveyor belt by at least one support. On the side on which the conveyor belt is accessible, for example, after opening the opening flap, it is advantageous if the support is as easy as possible to solve. This can be achieved, for example, by simple screw connections, which are released for changing the conveyor belt. The number, positioning and method of attachment and mounting of the detachably mounted supports depends on the size of the grinding machine, the number of grinding units used and the type of grinding, as this significantly determines how much the on the workpiece and thus on the conveyor belt is applied pressure exerted by the grinding units.

Advantageously, the grinding machine has a suction device, by means of which a workpiece lying on the conveyor belt can be subjected to a negative pressure. As a result, on the one hand, a holding force on the workpiece is increased, so that even with larger forces applied by the grinding unit to the workpiece forces the workpiece can not slip along the conveyor belt or move. On the other hand, it is achieved that grinding chips or grinding dust are sucked through the suction device and thus the contamination and contamination of the interior of the grinding machine with grinding dust or grinding chips is reduced.

Preferably, the grinding machine has a plurality of grinding modules, each having at least one grinding unit and a conveyor belt. In this case, each grinding module is advantageously removable separately from the grinding machine and, for example, replaced by another module. Each module has in a preferred embodiment at least one opening flap, more preferably a door through which a part of the housing, which belongs to the module, can be opened, whereby the conveyor belt is accessible.

Advantageously, the grinding machine has a suction chamber, which is arranged below the conveyor belt and has a bottom inclined to the horizontal.

Preferably, the grinding machine has a suction device, by means of which a workpiece lying on the conveyor belt can be subjected to a negative pressure, wherein the suction chamber is part of the suction device. The suction chamber is carried out as a rule as part of the suction device, but can also be used in the context of the present invention without the possibility to pressurize it with negative pressure. The abrasive chips or sanding dust to be removed is then led out of the grinding area of the grinding machine by the inclined bottom and its own weight and collected and can be easily removed.

A suction chamber arranged below the conveyor belt is preferably arranged only below the part of the conveyor belt on which the workpieces are transported by the grinding machine. The conveyor belt is usually a revolving endless belt, which forms a closed contour. Preferably, the suction chamber is disposed within this contour as directly as possible below the conveyor belt. For a variety of embodiments, it is sufficient if the suction chamber is arranged only in a partial area below the conveyor belt. This sub-area advantageously corresponds to the area in which above the conveyor belt, the grinding unit is arranged. This is the area where grinding chips and sanding dust are created, which are to be removed through the suction chamber. Advantageously, the bottom of the suction chamber with the horizontal at an angle of at least 5 °, preferably at least 10 °, more preferably at least 15 °, and at most 30 °, preferably at most 25 °, more preferably at most 20 °. To be particularly advantageous, it has been found that the bottom of the suction chamber is inclined perpendicular to the transport direction, along which the workpiece can be transported by the conveyor belt. This means that the workpiece is transported along the transport direction and the inclination extends to the right or left thereof. Abrasive dust and grinding chips, which are created by machining the surface of the workpiece with the grinding unit, can pass through existing in the conveyor belt holes or openings in the suction chamber, from where they can be sucked. This is further simplified and made more efficient by the inclined bottom of the suction chamber. In this way, the remaining contamination of the grinding machine with grinding dust and grinding chips made of a metal is significantly reduced or ideally completely avoided.

Advantageously, the suction chamber is connected to the lower end of the floor with a suction device or connectable. Due to this, grinding dust and grinding chips can be sucked out of the suction chamber. The bottom of the suction chamber is thus inclined to this suction device.

Advantageously, the conveyor belt is coated with an anti-adhesion coating. Particularly advantageously, the inside of the suction chamber, but at least the bottom of the suction chamber is coated with an anti-adhesion coating. An advantageous material is a polymer or a mixture of several polymers for the anti-adhesion Coating exposed. This also reduces the residual contamination and contamination of the conveyor belt and the suction device, in particular the suction chamber, and thus also reduces the cleaning effort.

Preferably, the bottom of the suction chamber can also be excited mechanically, that is, in particular, be set in vibration. These can be regular oscillations such as sound waves or individual regularly or irregularly recurring shocks. As a result, chips or dust, which has settled at the bottom of the suction, be moved so that it collects and removed, for example, can be sucked.

Advantageously, the grinding machine has a plurality of conveyor belts and a plurality of suction devices, wherein the suction devices each have a suction chamber with an inclined bottom. If the grinding machine is equipped with a plurality of grinding aggregates, which may be different or identical, it has proved to be advantageous if each of the aggregates is arranged in a grinding machine module which can be exchanged separately or removed from the grinding machine separately and from the other modules , For this purpose, it is advantageous if each of the modules, which may for example have one or two grinding units, have their own conveyor belt, which is only responsible for the transport of the workpiece within the grinding machine module. As a result, on the one hand, a carryover of grinding chips or grinding dust is prevented by an excessively long conveyor belt through the entire grinding machine and also allows easy interchangeability and expandability of the individual units and modules, for example, for cleaning, maintenance or replacement purposes.

Advantageously, the at least one conveyor belt can be replaced without the grinding unit having to be removed. For this purpose, for example, a surrounding the grinding units housing the grinding machine can be opened. After any existing supports are removed, which hold the transport table, which has the conveyor belt in position, have been removed, the conveyor belt can be removed. For this purpose, for example, a clamping device, which is responsible for a sufficient tension on the conveyor belt, be solved. The abrasive belt can then be easily removed without the need to completely disassemble the sanding machine or remove a sanding unit or grinding module from the sanding machine.

Advantageously, the grinding machine has a grinding tool or grinding unit with at least one brush with abrasive bristles and a planning unit. A planning unit is a functional unit within the grinding machine which, for example, in a special operating mode of the grinding machine, ensures that the concentricity and the straightness of the grinding tool, in particular a brush roller, are restored. This particular mode of operation may, for example, be in the form of a predetermined program stored in an electronic data storage which may be retrieved and executed by an electronic controller of the grinding machine. It is therefore only very rarely necessary with a grinding machine according to the invention to remove the actual grinding tool, in particular the brush roller, from the grinding machine. This is only necessary if the brush roller is to be completely replaced. If it is determined that the contact pressure of the grinding tool is no longer constant over the width of the brush roller or over the spatial extent of individual plate brushes, the special operating mode of the grinding machine is triggered manually, for example. In this case, the concentricity of the concentricity and the straightness of the brush roller are restored. This can be done within a few minutes, so that after the expiration of this period, when the program stored, for example, in the electronic data memory has been run through, the grinding machine is fully operational again and provides almost optimal grinding results.

Advantageously, the planning unit has at least one leveling tool for shortening at least a portion of the abrasive bristles.

When grinding with the grinding machine individual abrasive bristles of the grinding tool are more stressed than others and take advantage in particular more, so that they have, for example, a shorter length than, for example, arranged on the edge of the grinding tool abrasive bristles. In order to be able to ensure an optimum grinding result, all abrasive bristles of the brush, in particular of the brush roller, are advantageously shortened to a length so as to achieve a homogeneous grinding result. Of course, by the planning unit and a non-homogeneous length of the individual abrasive bristles can be adjusted to each other by shortening abrasive bristles in different areas of the grinding tool to different lengths, if desired and advantageous.

The leveling tool may for example consist of a plurality of cutting elements, which are arranged for example over the width of the grinding tool and thus on the Whole width at the same time can shorten the abrasive bristles of the abrasive. In this case, the grading tool can be designed as a large cutting element, for example, a blade extending across the entire width or scissors or consist of a plurality of different juxtaposed individual elements, then different lengths of abrasive bristles can be adjusted at different points of the grinding tool.

Alternatively, it has proven to be advantageous if the leveling tool is arranged displaceably in a direction perpendicular to the transport direction. The leveling tool itself can then be spatially small and thus formed with a relatively low inherent weight, so that the expenditure on equipment which is to be operated in such a grinding machine for the planing unit is significantly reduced. In particular, in a brush roller, it is advantageous if the planning unit in a direction perpendicular to the transport direction, ie in a grinding machine from left to right and vice versa is movable and can be accessed at any point across the width of the brush roller. Since the brush roller is set in rotation anyway, all bristles of the brush roller can be shortened to the desired length in this way.

Preferably, the at least one grinding tool and / or the leveling tool is arranged vertically adjustable. In any case, the grinding tool can be adjusted in height in a large number of known grinding machines in order to be able to make the distance between the grinding tool and the transport device variable and thus to be adjustable to workpieces of different thicknesses. In this case, it is advantageous if the leveling tool is not height-adjustable relative to the transport device, so that a height adjustment of the grinding tool at the same time has a change in the distance between the grinding tool and the leveling tool result. Of course, nevertheless, the leveling tool can be made adjustable in height, as long as the grinding tool and leveling tool are independently adjustable in height. Only in this way, the distance can be changed and so the length to which the abrasive bristles are shortened by the leveling tool set.

Preferably, the grinding tool has a plurality of disc brushes, which rotate along a circulation contour, wherein the at least one leveling tool is arranged next to the transport device. In the event that the grinding tool has a brush roller, the arrangement of the leveling tool above this brush roller has been found to be advantageous because the bristles in the rotating brush anyway in this direction. However, if disc brushes are used, the situation is different. In a disc brush, all abrasive bristles are usually directed towards the workpiece and the axis of rotation about which the disc brush rotates or pivots is perpendicular to the transport plane of the transport device. Also in this embodiment, it is possible to arrange the leveling tool above the plate brushes. In this case, if the particular operating mode of leveling is performed, the orientation of the plate brushes would have to be changed and the abrasive bristles of the plate brushes would be oriented towards the leveling tool. Although this is possible, but has an increased equipment and technical effort.

A structurally simpler solution is possible if the plate brushes, which also rotate on a circulation contour in addition to the rotation about its axis of rotation, are also moved in an area adjacent to the transport device, so that there are sections of the circulation contour in which the plate brushes and the Abrasive bristles of the disc brushes can not come into contact with a workpiece, which is located on the transport device. In these areas, in which, for example, reversal points and curves of the circulation contour lie, the at least one leveling tool can be arranged in a particularly simple and space-saving and therefore technically complicated manner. Advantageously, a plurality of leveling tools are arranged on both sides of the transport device in this case.

In a preferred embodiment, the grinding machine has a measuring device for measuring the length of the abrasive bristles. This can be done, for example, contactless, in particular via light barriers or by pressure or touch sensors that measure whether certain points still come into contact with the rotating abrasive bristles. Again, it has proved to be advantageous if the measuring device is set up to measure the length of the brushes at different points of the grinding tool. This means in particular that the length of the abrasive bristles can be measured at different positions across the width of the grinding tool. The grinding machine also has an electrical control adapted to bring the leveling tool into engagement with the abrasive bristles and thus to shorten the bristles when a difference in length between different bristles exceeds a predetermined limit. For example, if the electrical control detects, based on the measuring results of the measuring device, that a difference in length between the length of the bristles in the central region of the brushes and the bristles in the outer region of the brush acts a predetermined limit The electrical control may automatically switch on or off the planing mode of operation to cause the leveling tool to be engaged with the respective abrasive bristles so that the length difference between the individual bristles is reduced or brought to the desired level. Alternatively, the electrical control may also trigger a display or alarm device so that an operator of the grinding machine recognizes that cutting the abrasive bristles is necessary.

Advantageously, the predetermined limit depends on the length of the brushes. If the brushes are already relatively short, since they have been shortened several times, for example, it may be useful to select the predetermined limit relatively small in order to ensure that a relative change in length remains as small as possible. However, if the length of the brushes is still relatively large, for example in the case of a brush roller inserted freshly into the grinding machine, it is quite possible for larger differences in length to be tolerable.

With the aid of the accompanying drawings, an embodiment of the present invention will be explained in more detail below. It shows

1 The schematic representation of a device according to a first embodiment of the present invention in a front view,

2 - an enlarged section 1 .

3 - the device off 1 in a schematic side view and

4 - The device in a schematic three-dimensional view.

1 shows a device 1 according to a first embodiment of the present invention. It has two contact surfaces 2 which are arranged at a right angle to each other. Between them extends a caliper 4 that is along a displacement axis 6 , the bisector of the right angle between the two contact surfaces 2 corresponds and in 1 from top to bottom, slidably disposed. The two contact surfaces 2 are in one foot 8th arranged the device with which the device 1 can be placed on the workpiece to be measured.

The embodiment shown in the figures has the device 1 via a display device 10 , which is designed here as a dial gauge. The caliper 4 extend into the upper part of the device 1 and ensures that when moving an in 1 not shown pointer of the display device 10 around a central axis of the display device 10 is rotated, which is engaged, for example via intermeshing teeth with the caliper.

Once the caliper has reached its final position and the workpiece not shown in the figures on both contact surfaces 2 is applied, the position of the caliper can 4 by a clamping element 12 be fixed. There is a screw for that 14 present, through which the clamping element 12 attracted and so the caliper 4 relative to the display device 10 can be fixed. In this way, the device can be 1 easily remove from the workpiece and the otherwise possibly hard to read or visible display device 10 read off.

2 shows an enlarged view of the one with a circle 16 shown section 1 , You can see the two contact surfaces 2 as well as the vernier caliper 4 , The workpiece has an at least circular segment-shaped, but preferably circular cross-section, which passes through an inner circle 18 is shown. The to this inner circle 18 appropriate inner radius 20 is the radius to be determined by the device. It can be seen that when creating the inner circle 18 and thus the workpiece to the two contact surfaces 2 the caliper 4 in 2 is moved upwards. The two contact surfaces 2 form two parts of two sides of a square 22 that the inner circle 18 encloses. An outer circle 24 is around the square 22 rewritten and has an outer radius 26 , A measuring section 28 corresponds to the difference between the outer radius 26 and the inner radius 20 ,

From the triangle of points A, B and C can be the length of the outer radius 26 determine. The outer radius 26 calculates to the root 2 times the inner radius 20 , This allows the inner radius 20 from the measuring section 28 determine. The inner radius 20 It passes through the device 1 to determine, corresponds to the measuring section 28 divided by root 2 minus 1. By this simple calculation, consequently, the inner radius 20 that corresponds to the radius passing through the device 1 is to be determined in a particularly simple manner.

3 shows the device 1 in a side view and 4 shows the device 1 in a three-dimensional view. Each recognizes the display device 10 , the foot 8th and the clamping element 12 , In 4 are also the two contact surfaces 2 and the screw 14 to recognize.

LIST OF REFERENCE NUMBERS

1

 contraption

2

 contact surface

4

 measuring stick

6

 displacement axis

8th

 foot

10

 display

12

 clamping element

14

 screw

16

 circle

18

 inner circle

20

 inner radius

22

 square

24

 outer circle

26

 outer radius

28

 measuring distance

Claims (8)

Contraption ( 1 ) for determining a radius ( 20 ) a contour of a workpiece having at least a circular segment-shaped cross-section, wherein the device ( 1 ) - two contact surfaces ( 2 ) for applying the workpiece and - at least one caliper ( 4 ), wherein - the contact surfaces ( 2 ) are arranged at a right angle to each other and - the caliper ( 4 ) is slidably disposed along an angle bisector of the right angle such that the caliper ( 4 ) is displaceable by the workpiece to the two contact surfaces ( 2 ) is created. Contraption ( 1 ) according to claim 1, characterized in that the device ( 1 ) a measuring device for measuring the distance to which the caliper ( 4 ) is moved when the workpiece to the two contact surfaces ( 2 ) is created. Contraption ( 1 ) according to claim 2, characterized in that the device ( 1 ) has an electrical control, which is set up, from the measured distance the radius ( 20 ). Contraption ( 1 ) according to one of the preceding claims, characterized in that the device ( 1 ) a display device ( 10 ), which is set up the radius ( 20 ) or the distance to which the calliper ( 4 ) has been moved to display. Grinding machine for grinding a surface of a workpiece, the grinding machine having at least one grinding tool, characterized in that the grinding machine comprises a device ( 1 ) according to one of the preceding claims. Grinding machine according to claim 5, characterized in that the device ( 1 ) is arranged and set up a radius ( 20 ) to determine an edge of the workpiece. Grinding machine according to claim 5 or 6, characterized in that the device ( 1 ) is movable by an actuator to the workpiece. Grinding machine according to one of claims 5 to 7, characterized in that a through the device ( 1 ) certain radius ( 20 ) is used as a control parameter or controlled variable in an electrical control of the grinding machine.

Images