Control device, grinding and / or polishing machine and method

Abstract

The invention relates to a control device for a grinding and / or polishing machine (10). A sensor unit (12) is proposed which is intended to detect at least one assembly parameter relating to the assembly of a grinding and / or polishing pad (14), in particular a grinding disc (16), on the grinding and / or polishing machine (10), in particular incorrect assembly and / or its presence to prevent damage.

Description

State of the art

[0001] A control device for a grinding and / or polishing machine has already been proposed. Disclosure of the invention

[0002] The invention relates to a control device for a grinding and / or polishing machine.

[0003] A sensor unit is proposed which is intended to detect at least one assembly parameter relating to the assembly of a grinding and / or polishing pad, in particular a grinding disc, on the grinding and / or polishing machine, in particular incorrect assembly and / or its presence to prevent damage.

[0004] The design of the control device according to the invention advantageously provides a high level of safety, since in particular incorrect assembly is detected and thus injuries to the operator can be prevented. Advantageously, high reliability and / or service life can be provided, since in particular damage resulting from incorrect assembly and / or the absence of the grinding and / or polishing pad, especially the grinding disc, can be prevented.

[0005] Preferably, the control device is provided for a grinding and / or polishing machine. Preferably, the grinding and / or polishing machine is designed as a hand tool, particularly a portable one. Specifically, the grinding and / or polishing machine is designed as an eccentric sander or an orbital sander. Preferably, the grinding and / or polishing machine has at least one sanding disc, which can be attached and detached to the grinding and / or polishing machine, particularly to a drive unit of the grinding and / or polishing machine, by means of a screw connection. Preferably, the grinding and / or polishing machine has a sanding and / or polishing pad, which is designed to be connected to the sanding disc, particularly via a hook-and-loop fastener. Alternatively, the hand tool could also be designed as a multi-tool or a comparable hand tool.Preferably, the grinding and / or polishing pad is designed as sandpaper. The terms "intended" or "configured" are to be understood in particular as specifically programmed, designed, and / or equipped. The fact that an object is intended or configured for a specific function is to be understood in particular as the object fulfilling and / or performing this specific function in at least one application and / or operating state.

[0006] Preferably, the control device is configured to prevent the grinding and / or polishing machine from being switched on if a grinding and / or polishing pad is incorrectly mounted or removed. Preferably, the control device is configured to allow the grinding and / or polishing machine to be switched on if a grinding and / or polishing pad is correctly mounted. "Switching on" is understood to mean, in particular, the mechanical acceleration and / or movement of the grinding and / or polishing pad.

[0007] Preferably, the control device is arranged entirely within the grinding and / or polishing machine and / or is firmly connected to the grinding and / or polishing machine. Preferably, the control device is positively and / or materially bonded to the grinding and / or polishing machine. It is conceivable that the control device is designed as a retrofit kit that can be installed on or in an existing grinding and / or polishing machine.

[0008] Alternatively, the control device could be designed, at least partially, as an external assembly. For example, the control device could be connected to a smartphone, a desktop computer, or a comparable external computing unit. Preferably, the control device is designed to detect an assembly parameter. More preferably, the control device is configured to detect, and in particular distinguish, at least one correct and / or faulty assembly of the polishing pad and / or the grinding disc. An "assembly parameter" is understood to be, in particular, a parameter derived from a measured value of the sensor unit, which is designed to assume at least two states and which is designed to clearly distinguish at least one correct state from a faulty state.It is conceivable that the control device is designed to provide further information, such as type identification of the sanding disc and / or sanding pad, in particular regarding the color and / or perforation of the sanding pad, and / or another parameter, such as a rotational speed. It is also conceivable that the control device is configured to detect wear and / or the degree of contamination of the sensor unit and / or the perforation of the sanding disc and / or the sanding pad. The term "positive locking" is to be understood in particular as meaning that adjacent surfaces of positively locked components exert a holding force on each other acting in the normal direction of the surfaces. In particular, the components are in geometric engagement with one another.The term "materially bonded" is understood to mean in particular that the mass components are held together by atomic or molecular forces, such as in soldering, welding, gluing and / or vulcanizing.

[0009] Preferably, the sensor unit is designed to detect the assembly parameter. Preferably, the sensor unit is designed to provide the measured value for deriving the assembly parameter. Preferably, the sensor unit comprises at least one sensor element. This at least one sensor element could be configured as an optical sensor, an accelerometer, a vibration sensor, or the like. For example, the accelerometer could be configured to detect faulty assembly of the grinding wheel by means of vibration detection when the drive is started. Preferably, the sensor unit, and in particular at least one sensor element of the sensor unit, is arranged on an HMI (Human Machine Interface) of the grinding and / or polishing machine.Alternatively or additionally, the sensor unit, in particular the sensor element or another sensor element, is arranged on a PCBA (Printed Circuit Board Assembly) of the grinding and / or polishing machine. It is conceivable that measured values ​​from two or more sensors constitute at least one characteristic value or are at least taken into account. A "PCBA" is understood to mean, in particular, a circuit board made of an insulating material, which has, in particular, printed, electrically conductive traces. An "HMI" is understood to mean, in particular, an interface designed to enable communication between an operator and the grinding and / or polishing machine, in particular a control unit of the grinding and / or polishing machine. A "control unit" is understood to mean, in particular, a unit with at least one control electronics module.The term "control electronics" refers in particular to a unit comprising a processor unit, a memory unit, and an operating program stored in the memory unit.

[0010] Furthermore, it is proposed that the sensor unit be configured to detect the assembly parameter when the grinding and / or polishing machine is switched off. Advantageously, a particularly high level of safety can be provided, since the assembly parameter can be detected even when the machine is switched off, thus ensuring that it is only switched on if the assembly is correct. Preferably, the switched-off state is configured as a drive-free state. Preferably, the sensor unit is configured to detect the assembly parameter before the grinding and / or polishing machine is switched on. Preferably, the control device is configured to verify the assembly parameter before the grinding and / or polishing machine is switched on. In particular, the grinding and / or polishing machine remains deactivated until the assembly parameter indicates / detects a correct assembly of the grinding disc and / or the grinding pad.Preferably, the sensor unit is configured to continuously monitor the assembly parameter, for example, at regular intervals. Preferably, the assembly parameter is configured to indicate a fault condition, particularly a positive or negative one. For example, the positive fault condition is configured as at least a faulty assembly condition, and the negative fault condition as a fault-free assembly condition. Preferably, the grinding and / or polishing machine can only be switched on when the assembly parameter indicates the negative condition, particularly a fault-free assembly condition. A "switch-off condition" is understood to mean a standby mode and / or a preparation mode in which at least one power supply to the grinding and / or polishing machine is active and in which the drive is at least in a resting state.

[0011] Furthermore, it is proposed that the sensor unit include at least one optical sensor for detecting the assembly parameter. Advantageously, a particularly high response speed can be provided, since an optical sensor, in particular, has a very short response time. Advantageously, a particularly wide operating range can be provided, since an optical sensor, in particular, can also be used in a standby state. Preferably, the optical sensor is designed as a brightness sensor and / or light sensor. Preferably, the optical sensor is designed as a photodiode. Preferably, the photodiode is connected in an electrical amplifier circuit. Preferably, the photodiode is configured to generate an electric current that is at least substantially proportional to the light intensity incident, in particular on a measuring surface of the photodiode.Preferably, the control device includes a limit value for the measured value, in particular the current generated by the photodiode, the exceedance of which triggers the assembly parameter to indicate a faulty assembly condition. Preferably, the optical sensor is configured to detect light intensity in a space behind the grinding wheel. Preferably, this space behind the grinding wheel is a cavity within the grinding and / or polishing machine, bounded at least by the grinding wheel and at least one housing of the grinding and / or polishing machine. Alternatively, the sensor unit may include at least one optical fiber configured to transmit the light intensity in the space behind the grinding wheel to the measuring surface of the photodiode.It is conceivable that the optical sensor or another optical sensor of the sensor unit is configured for type identification of the grinding and / or polishing pad, for example, via the color of the grinding and / or polishing pad. For instance, a specific brightness could be detectable depending on the color of the grinding and / or polishing pad and / or via perforations in the grinding disc and / or the polishing pad. Alternatively or additionally, the optical sensor or the other optical sensor could be configured to provide a time-dependent measurement profile, particularly frequency, especially via the perforations in the grinding disc and / or the grinding pad. The control device could be configured to determine or at least estimate a rotational speed during operation based on the measurement profile, particularly frequency.It is conceivable that the optical sensor and / or the additional optical sensor is designed to detect wear and / or contamination.

[0012] Furthermore, a control unit is proposed which is designed to output a control parameter for the grinding and / or polishing machine and / or a warning message, depending on the assembly parameter. Advantageously, a high level of user-friendliness can be provided, as the operator is presented with a suggested course of action. Preferably, the control unit is configured to generate the assembly parameter from the measured value of the sensor unit, in particular by comparing it with the limit value. Preferably, the control unit is configured to determine the control parameter, in particular at least based on the assembly parameter. It is conceivable that the control unit is designed as a processing unit of the grinding and / or polishing machine.A "control parameter" should in particular be understood to be a state which is designed, for example, as "operational" or "safety shutdown".

[0013] Preferably, the grinding and / or polishing machine has at least one display configured to output at least the control parameter, and / or the warning message, and / or a recommendation for the operator, and / or comparable information. Preferably, the grinding and / or polishing machine has at least one output unit. Preferably, the output unit includes at least the display. Alternatively or additionally, the output unit could include at least one further optical output element, for example, a colored LED, or at least one further acoustic output signal, for example, a warning tone. Preferably, the control unit is configured to output at least the control parameter, and / or the warning message, and / or the recommendation for action, and / or comparable information, at least via the display.Alternatively or additionally, it is conceivable that the control and / or regulating unit could be set up to output at least the control parameter, and / or the warning message and / or the recommendation for action and / or the comparable information via an external output device, such as a smartphone and / or the workplace computer or the like.

[0014] Furthermore, it is proposed that the control parameter includes a command for a safety shutdown of the grinding and / or polishing machine. Advantageously, a particularly high level of safety can be provided, as operation is automatically prevented, especially in the event of a fault. Preferably, the control unit is configured to send a command for a safety shutdown and / or a command to enable operation to the drive unit, depending on the control parameter. Preferably, the control unit is configured to suppress an operation-enable command until the control parameter transmits the state "ready for operation". It is conceivable that the control unit sends the control parameter to the processing unit of the grinding and / or polishing machine.Preferably, the safety shutdown must be actively confirmed by an operator in the presence of a positive assembly parameter, in particular the state of faultless assembly, in order to set the control parameter to ready for operation.

[0015] Additionally, a grinding and / or polishing machine is proposed, which incorporates the control device. Advantageously, a high level of safety can be ensured, as incorrect assembly is detected and operator injuries can be prevented. Advantageously, high reliability and / or a long service life can be ensured, as damage resulting from incorrect assembly and / or the absence of the grinding and / or polishing pad, especially the grinding disc, can be prevented. It is conceivable that the control device is arranged partially or completely external to the grinding and / or polishing machine.

[0016] It is further proposed that the control device be arranged on the grinding and / or polishing machine, and in particular integrated into the grinding and / or polishing machine. Advantageous properties regarding design, appearance, and / or service life can be provided, since the control device can be particularly well integrated with the grinding and / or polishing machine. Preferably, the control device is fully integrated into the grinding and / or polishing machine. Preferably, the control device is integrated into the HMI or the PCBA.The term "integrated" shall be understood to mean, in particular, a form-fit and / or material-fit connection with a circuit board and / or a housing and / or a comparable component of the grinding and / or polishing machine, and, in particular, an electrically conductive connection with the control and / or regulating unit and / or the computing unit and / or at least one other electronic component of the HMI or the PCBA.

[0017] Furthermore, it is proposed that the sensor unit be arranged in close proximity to the grinding and / or polishing pad holder of the grinding and / or polishing machine. Advantageously, high precision can be achieved because the sensor unit is located in this close proximity. Preferably, the grinding and / or polishing pad holder is formed by the grinding disc. Preferably, the grinding and / or polishing pad holder is arranged on the side of the grinding disc opposite the drive unit of the grinding and / or polishing machine and / or the HMI and / or the sensor unit. Preferably, the grinding and / or polishing pad holder is designed to secure the grinding and / or polishing pad to the grinding disc in a form-fitting manner, particularly via a hook-and-loop fastener. Preferably, the sensor unit has direct line of sight to the grinding disc.In particular, the near range of the associated sensor unit is formed by all points which are less than 20 cm away from the associated grinding and / or polishing pad holder, preferably 10 cm, advantageously 5 cm and preferably 1 cm.

[0018] Furthermore, it is proposed that, in a process step, a sensor unit of the control device detects, particularly optically, an assembly parameter relating to the mounting of a grinding and / or polishing pad on a grinding and / or polishing machine. Advantageously, a high level of safety can be provided, as incorrect assembly is detected, thereby preventing operator injury. Advantageously, high reliability and / or service life can be provided, as damage resulting from faulty assembly and / or the absence of the grinding and / or polishing pad, especially the grinding disc, can be prevented. Preferably, the light intensity incident on the measuring surface of the optical sensor is converted into a proportional electrical current, which is then converted into a voltage signal, for example, via a transimpedance amplifier.Preferably, the assembly parameter is determined by the control unit by comparing the measured value with a limit value. If the limit value is exceeded, the assembly parameter indicates a faulty assembly condition. If the limit value is not reached, the assembly parameter indicates a fault-free condition.

[0019] Furthermore, it is proposed that, depending on the assembly parameter, a control parameter for the grinding and / or polishing machine and / or a warning message be output in a process step. This offers the advantage of high user convenience, as the operator receives an error message. If the assembly parameter indicates a fault-free state, the control parameter "Ready for Operation" is set. If the assembly parameter indicates a faulty assembly state, the control unit initiates a safety shutdown via the control parameter. The drive remains deactivated until the control parameter is set to "Ready for Operation".

[0020] The control device, the grinding and / or polishing machine, and the method according to the invention are not to be limited to the application and embodiment described above. In particular, the control device, the grinding and / or polishing machine, and the method according to the invention may, to achieve a functionality described herein, comprise a different number of individual elements, components, units, and process steps than that specified herein. Furthermore, values ​​within the specified limits of the value ranges stated in this disclosure shall also be considered disclosed and freely usable. drawing

[0021] Further advantages will become apparent from the following description of the drawing. The drawing illustrates an embodiment of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0022] They show: Fig. 1 a grinding and / or polishing machine, Fig. 2 a schematic representation of a bottom view of a grinding disc of the grinding and / or polishing machine, Fig. 3 a schematic sectional view of the grinding and / or polishing machine with a control device and Fig. 4 a schematic flowchart of a procedure for operating the grinding and / or polishing machine. Description of the exemplary embodiment

[0023] The Fig. Figure 1 shows a grinding and / or polishing machine 10. The grinding and / or polishing machine 10 is designed as a hand tool. The grinding and / or polishing machine 10 could be designed as an eccentric sander, an orbital sander, or a comparable hand tool. The grinding and / or polishing machine 10 has a grinding motion. The grinding motion is designed as a translational and / or eccentric motion. The grinding motion is not a purely rotary motion. The grinding and / or polishing machine 10 has a housing 34. The grinding and / or polishing machine 10 has a human-machine interface (HMI) 26. The HMI 26 is integrated into the housing 34. The HMI 26 is configured to establish an interface between a processing unit 46 of the grinding and / or polishing machine 10 and an operator, see Figure 1. Fig. 3. The HMI 26 has an output unit 24. The output unit 24 is configured to provide information to the operator. The output unit 24 could be designed as a display. It is conceivable that the output unit 24 is designed as indicator lights or as a comparable primitive display unit 24. The grinding and / or polishing machine 10 has a PCBA (Printed Circuit Board Assembly) 44, cf. Fig. 3. The PCBA 44 is designed at least as part of the computing unit 46 of the grinding and / or polishing machine 10.

[0024] The Fig. Figure 2 shows a schematic bottom view of the grinding and / or polishing machine 10. The grinding and / or polishing machine 10 has a drive unit 28. The grinding and / or polishing machine 10 has a grinding disc 16. In its assembled state, the grinding disc 16 is positively and / or non-positively connected to the drive unit 28. A grinding and / or polishing pad 14 can be attached to a side of the grinding disc 16 facing away from the drive unit 28. The grinding and / or polishing pad 14 is designed as a piece of abrasive or polishing paper. The grinding disc 16 has a grinding and / or polishing pad holder 38. The grinding and / or polishing pad holder 38 is designed as an adhesive element 20. The adhesive element 20 is designed as a hook and loop fastener. The adhesive element 20 could be designed as a comparable adhesive, positive, or material-locking element.The adhesive element 20 is designed to form a connection with a corresponding adhesive element of the sanding and / or polishing pad 14. The adhesive element 20 is arranged on a sanding disc surface 42. The sanding disc surface 42 is located on the side of the sanding disc 16 opposite the drive unit 28. The sanding and / or polishing pad 14 is positively connected to the sanding disc 16, for example, via a hook-and-loop fastener.

[0025] The Fig. Figure 3 shows a schematic sectional view of the grinding and / or polishing machine 10. The grinding and / or polishing machine 10 has a grinding disc rear chamber 36. The grinding disc rear chamber 36 is bounded by the housing 34. The grinding disc rear chamber 36 is bounded by the grinding disc 16. The grinding disc rear chamber 36 is bounded by the drive unit 28. The grinding disc rear chamber 36 is bounded by a fan wheel 48 of the drive unit 28. Additionally, the grinding disc rear chamber 36 could be bounded by the HMI 26. It is conceivable that the grinding disc rear chamber 36 is bounded by other components (not shown). The grinding disc rear chamber 36 is formed as a cavity within the grinding and / or polishing machine 10. The grinding and / or polishing machine 10 has a control device. The control device is arranged on the grinding and / or polishing machine 10.The control device is positively or materially connected to the grinding and / or polishing machine 10. The control device is integrated into the grinding and / or polishing machine 10. The control device is located entirely within the grinding and / or polishing machine 10. The control device is located in the grinding disc rear compartment 36. Alternatively, the control device could be designed as a retrofit kit that can be attached to or inside the grinding and / or polishing machine 10.

[0026] The control device includes a control and / or regulating unit 22. The control and / or regulating unit 22 could be configured as the computing unit 46 of the grinding and / or polishing machine 10. The control device includes a sensor unit 12. The sensor unit 12 is electronically connected to or integrated into the control and / or regulating unit 22. The sensor unit 12 is configured to detect an assembly parameter. The assembly parameter indicates the mounting status of the grinding disc 16 and / or the grinding and / or polishing pad 14 on the grinding and / or polishing machine 10. The sensor unit 12 is configured to detect the assembly parameter when the grinding and / or polishing machine 10 is switched off. The sensor unit 12 is configured to detect the assembly parameter when the drive unit 28 is de-energized.The sensor unit 12 is designed to detect incorrect assembly and / or the presence of the grinding disc 16 and / or the grinding and / or polishing pad 14 in order to prevent damage. The sensor unit 12 is located in the immediate vicinity of a grinding and / or polishing pad holder 38 of the grinding and / or polishing machine 10. The sensor unit 12 is located on or connected to the HMI 26. The sensor unit 12 has an optical sensor 18. The optical sensor 18 is bonded to the HMI 26. The optical sensor 18 is located in the recess 36 behind the grinding disc. The optical sensor 18 is less than 3 cm from the grinding disc 16. The optical sensor 18 is located in a radial section of the grinding disc 16, which is outside the section of the grinding disc 16 with a perforation 40, see Figure 1. Fig. 2. Alternatively, the optical sensor 18 could also be arranged on the HMI 26. The optical sensor 18 could be connected to an optical fiber. The optical fiber could be configured to transmit light to the optical sensor 18 at a distance of less than 3 cm from the grinding disc 16. It is conceivable that the control device has another optical sensor 18, which is arranged, for example, in a radial area of ​​the perforation 40. This additional sensor 18 could be configured to detect the grinding and / or polishing pad 14, for example, based on the color of the grinding and / or polishing pad 14. This additional sensor 18 could be configured to detect the rotational speed of the grinding disc 16 based on the perforation 40.

[0027] The optical sensor 18 is configured as a photodiode. The optical sensor 18 is designed to generate a sensor signal. The sensor signal is expressed as a current. The current is proportional to the light intensity incident on the measuring surface of the optical sensor 18. The optical sensor 18 is connected to an electronic amplifier circuit. The amplifier circuit is configured to convert the current generated by the optical sensor 18 into an output voltage. The amplifier circuit is configured to amplify the current generated by the optical sensor 18. The amplifier circuit is configured to output a voltage signal. The control unit 22 has a limit value for the voltage signal. If the limit value is exceeded, the mounting parameter has a positive value. If the limit value is not reached, the mounting parameter has a negative value.A positive value indicates a faulty condition. A negative value indicates a fault-free condition.

[0028] The control unit 22 is designed to output a control parameter for the grinding and / or polishing machine 10, depending on the assembly parameter. The control parameter contains a command for a safety shutdown of the grinding and / or polishing machine 10. The control parameter also contains a command indicating an operational state. The control unit 10 is configured to output a warning message if the control parameter indicates a safety shutdown.

[0029] The Fig. Figure 4 shows a schematic flowchart of a procedure for operating a control device.

[0030] In process step 30, the assembly parameter is recorded. The assembly parameter is measured continuously. Alternatively, the assembly parameter could also be measured at time intervals. The assembly parameter is measured in a drive-free state. The assembly parameter is measured before the drive unit 28 of the grinding and / or polishing machine 10 is switched on. The assembly parameter is recorded by means of the sensor unit 12. For this purpose, the light intensity is recorded by the measuring surface of the optical sensor 18 and converted into a proportional electrical current. The electrical current is converted into an electrical voltage signal. The electrical voltage signal is retrieved by the control and / or regulation unit 22. The assembly parameter is generated by the control and / or regulation unit 22 by comparing the output voltage with the limit value. A fault condition is detected by means of the assembly parameter.A fault-free condition is detected using the assembly parameter.

[0031] In a further process step 32, a control parameter for the grinding and / or polishing machine 10 and / or a warning message is output, depending on the assembly parameter. The control parameter transmits a command to the processing unit 46 of the grinding and / or polishing machine 10 for a safety shutdown if the assembly parameter indicates a faulty state. Alternatively or additionally, the warning message is output via the output unit 24 if the assembly parameter is faulty. The grinding wheel 16 can only be set in motion by the drive unit 28 if the control parameter signals an operational state.

Claims

[1] Control device for a grinding and / or polishing machine (10), characterized by a sensor unit (12) which is intended to detect at least one assembly parameter relating to the assembly of a grinding and / or polishing pad (14), in particular a grinding disc (16), on the grinding and / or polishing machine (10), in particular incorrect assembly and / or its presence to prevent damage. [2] Control device according to claim 1, characterized by , that the sensor unit (12) is configured to detect the assembly parameter in a switched-off state of the grinding and / or polishing machine (10). [3] Control device according to claim 1 or 2, characterized by , that the sensor unit (12) has at least one optical sensor (18) for detecting the assembly characteristic. [4] Control device according to any one of the preceding claims, characterized bya control and / or regulating unit (22) which is intended to output a control parameter for the grinding and / or polishing machine (10) and / or a warning message depending on the assembly parameter. [5] Control device according to claim 4, characterized by , that the control parameter contains a command to a safety shutdown of the grinding and / or polishing machine (10). [6] Grinding and / or polishing machine (10) with a control device according to one of the preceding claims. [7] Grinding and / or polishing machine according to claim 6, characterized by that the control device is arranged on the grinding and / or polishing machine (10), in particular is integrated into the grinding and / or polishing machine (10). [8] Grinding and / or polishing machine according to claim 7, characterized by, that the sensor unit (12) is arranged in the immediate vicinity of a grinding and / or polishing pad holder of the grinding and / or polishing machine (10). [9] Method for operating a control device, in particular according to any one of claims 1 to 5, characterized by , that in a process step (30) a mounting characteristic relating to the mounting of a grinding and / or polishing pad (14) on a grinding and / or polishing machine (10) is detected, in particular optically, by means of a sensor unit (12) of the control device. [10] Method according to claim 9, characterized by , that in a process step (32) depending on the assembly parameter a control parameter for the grinding and / or polishing machine (10) and / or a warning message is issued.

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