Power tool with disk-shaped tool element and method for fastening and releasing the tool element - Patents.com

Abstract

The present invention relates to a power tool having a disk-shaped tool element. The tool element can be fastened to a drive shaft of the power tool by a fastening nut. The drive shaft is configured to transmit torque of a drive part to the tool element. The power tool is configured to loosen or tighten the fastening nut by at least one torque impulse of the drive part of the power tool. In a second aspect, the invention relates to a method for fastening a disk-shaped tool element to a drive shaft of a power tool, and in an additional aspect, to a method for releasing the disk-shaped tool element from the drive shaft of a power tool. In yet another aspect, the invention relates to the use of torque impulses that can be generated by the drive part of the power tool to loosen or tighten the fastening nut for fastening the disk-shaped tool element to the power tool.

Description

[Technical field]

[0001] The present invention relates to a power tool having a disk-shaped tool, which can be fastened to a drive shaft of the power tool by means of a fastening nut, the drive shaft being arranged to transmit the torque of a drive to the tool. The power tool is characterized in that the power tool is arranged to loosen or tighten the fastening nut by at least one torque impulse of the drive of the power tool. In a second aspect, the invention relates to a method for fastening a disk-shaped tool to a drive shaft of the power tool and in a further aspect to a method for releasing a disk-shaped tool from a drive shaft of the power tool. In yet another aspect, the invention relates to the use of torque impulses which can be generated by the drive of the power tool to loosen or tighten a fastening nut for fastening the disk-shaped tool to the power tool. [Background technology]

[0002] Power tools with disk-shaped tools are known in the prior art. Examples of these are angle grinders or cut-off grinders that can grind surfaces or cut substrates. Disk-shaped tools include, in particular, grinding or cut-off disks that are used to carry out the corresponding operations. The grinding or cut-off disks can be studded with diamond pieces to further improve the cutting performance of the tool.

[0003] Such grinding or cut-off discs are typically fastened to the power tool by means of fastening nuts. To be able to guarantee high operational reliability, these fastening nuts must be fastened with a high force. This often requires the power tool manufacturer to provide corresponding auxiliary tools, such as socket or screw wrenches, with which the grinding or cut-off discs can be fastened to the power tool. These auxiliary tools are usually designed to be particularly small and compact and are specially adapted to the nut to be fastened. However, such additional auxiliary tools, in particular due to their small size, often end up being lost. However, such loss is particularly troublesome and causes many problems, since often only one suitable wrench for loosening or tightening the fastening nut is present on the construction site. Re-acquiring the appropriate auxiliary tool for loosening or tightening the fastening nut can therefore lead to significant delays and time losses on the construction site.

[0004] In order to address the need for portable auxiliary tools, the prior art has proposed using quick clamping nuts that can be used to fasten grinding or cut-off discs to power tools without corresponding additional auxiliary tools. However, such quick clamping nuts are very costly and require extra space for installation. As a result, the use of quick clamping nuts can constitute a clear challenge in compact devices. Moreover, quick clamping nuts can also be lost on the construction site, so that in this case there is always a need to carry additional replacement nuts. However, this is often not done for cost reasons, so that in this case too delays and time losses can occur. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide an electric tool that allows the fastening of a disk-shaped tool without additional auxiliary tools. Moreover, it would be welcomed by those skilled in the art if it were possible to use standard, commercially available, cost-effective and readily available fastening nuts for fastening the tool in order to effectively avoid delays and time losses at the construction site. [Means for solving the problem]

[0006] This object is achieved by the subject matter of the independent claims. Advantageous developments of the subject matter of the independent claims can be found in the dependent claims.

[0007] The object is achieved by a power tool having a disk-shaped tool, the tool being capable of being fastened to a drive shaft of the power tool by means of a fastening nut, the drive shaft being arranged to transmit the torque of the drive to the tool. The power tool is characterized in that the power tool is arranged to loosen or tighten the fastening nut by at least one torque impulse of the drive of the power tool. In other words, the fastening nut can be loosened or tightened by a torque impulse of the drive of the power tool. Preferably, the fastening nut can be loosened or tightened by at least one torque impulse of the drive of the power tool, where the torque impulse can be output in particular at a frequency of 1-10 Hz. In the present invention, the power tool and its drive are preferably arranged to output a rapid succession of torque impulses, where the output frequency can be in the range of 1-10 Hz.

[0008] In the present invention, the drive of the power tool preferably comprises a motor. The inventors have realized that such torque impulses of sufficient strength can be generated by the power tool, in particular in the case of a drive with an electronically commutated motor, to allow loosening or tightening preferably standard commercially available fastening nuts. In this respect, the present invention utilizes the capabilities of the power tool to solve a technical problem that remained unsolved up to now. The torque impulses that can be generated by the drive of the power tool used to loosen or tighten fastening nuts have not been considered by the skilled person in this respect up to now. Rather, what was previously assumed by the skilled person was that the fastening nuts have to be loosened or tightened with the aid of additional auxiliary tools specially provided for that purpose, or that the auxiliary tools specially provided for that purpose can be omitted only when using costly quick clamping nuts for fastening grinding or cut-off disks. The present invention offers the possibility that the fastening of disk-shaped tools can be carried out here without the need to use special auxiliary tools, preferably with standard commercially available, cost-effective and easily available fastening nuts. As a result, the present invention is precisely a departure from the prior art and the disadvantages of the skilled person.

[0009] According to the invention, it is provided that the grinding or cut-off disk can be fastened to the drive shaft of the power tool by means of a standard commercially available fastening nut, whereby the drive shaft is arranged to transmit the torque of the drive to the tool. It is also provided that the drive of the power tool comprises a motor, which generates a torque for driving the disk-shaped tool. This torque can preferably be transmitted to the tool by means of the drive shaft. In a very particularly preferred embodiment of the invention, the motor is an electronically commutated motor, which preferably constitutes a brushless drive of the power tool. The inventors have recognized in particular that an electronically commutated motor is capable of generating torque impulses, by which the fastening nut can be loosened or tightened. In particular, the torque impulses generated by the brushless motor exhibit a sufficiently large power transmission or a sufficiently large torque to ensure that a standard commercially available fastening nut can be fastened reliably and stably or, conversely, that a reliable and stable connection between the fastening nut and the power tool can be released by the generated torque impulses.

[0010] In the present invention, the clamping nut can preferably be loosened or tightened unassisted, solely by the torque impulse of the drive part of the power tool. This ability represents an essential advantage of the present invention.

[0011] The motor of the power tool is preferably an electrically commutated motor.The drive of the power tool is preferably arranged to output torque impulses in rapid succession.

[0012] In the present invention, impulses, i.e. torque impulses, are preferably used to generate a torque greater than the counter torque generated by the mass inertia of the nut and of the disk-shaped tool connected to the nut, and this connection is preferably brought about by an engagement based on frictional forces. The impulses can be output several times per second depending on the configuration of the drive. In the present invention, the impulses are preferably output at a frequency in the range of 1-10 Hz. In other words, the impulses can be output, for example, 1-10 times per second. In other words, the power tool or its drive can be set up to output torque impulses in rapid succession.

[0013] In a preferred embodiment of the invention, the power tool has at least one sensor for monitoring the torque impulse. In other words, in the present invention, the power tool preferably has a sensor for monitoring the output of the torque impulse. The output of the torque impulse in the context of the present invention is preferably performed in a sensor-monitored manner, i.e. by means of a sensor. The sensor can preferably be, but is not limited to, an incremental encoder, an absolute encoder, an accelerometer, and / or a Hall sensor. The Hall sensor and the absolute encoder are preferably arranged to determine the rotational position of the motor. The at least one sensor is preferably arranged in particular to determine the change in the rotational position of the motor.

[0014] It may also be preferred in the present invention that sensorless feedback is provided to the motor, making it possible to identify which input energy results in a particular angular change of the motor. In other words, the sensorless feedback can be used to detect the interaction or dependency between the input energy and the resulting angular change of the motor.

[0015] From the time profile of these variables it is possible to determine whether the nut is already tightened or whether it may be loosened. In particular, it is possible to derive whether the nut is already fastened on the power tool by the rotational position or angle change of the motor. The inventors of the present application have recognized that the total inertia changes depending on whether the disk-shaped tool is connected to the output shaft or released from the output shaft. The use of sensorless feedback is associated with the advantage that it is not necessary to use any sensors, limiting the complexity of the power tool.

[0016] In a second aspect, the invention relates to a method for fastening a disk-shaped tool to a drive shaft of a power tool. The proposed fastening method comprises the following method steps: a) providing a power tool and a disk-shaped tool for the power tool; b) providing a fastening nut for fastening the tool to the power tool; c) connecting the power tool and the tool with a fastening nut; and d) outputting a torque impulse through a drive of the power tool, so that the tool is fastened to the drive shaft of the power tool by the fastening nut; Includes.

[0017] In the present invention, for the proposed method, standard commercially available fastening nuts for fastening the tool to the power tool are preferably provided and can be used. The terms, definitions and technical advantages introduced for the power tool preferably apply to the proposed method and the proposed use as well. An essential advantage in the case of the proposed method and the proposed power tool is that the power tool can actually perform the method without any assistance on the part of the user and no longer requires the holding of an object or item. This allows the user of the power tool to maintain optimal hand freedom and to perform other tasks with his or her remaining hand.

[0018] In a further aspect, the present invention relates to a method for releasing a disk-shaped tool from a drive shaft of a power tool. The proposed releasing method comprises the following method steps: a) providing a power tool, the tool being fastened by a fastening nut; b) outputting a torque impulse via a drive of the power tool, so that the fastening nut is loosened; and c) separating the power tool from the tool; Includes.

[0019] In the present invention, for the proposed release method, standard commercially available fastening nuts can be provided and used. The output of the torque impulse is preferably performed in such a way that the fastening nut can be loosened from the drive shaft without further aids. In particular, the separation of the power tool and the tool is performed without tools or aids.

[0020] In yet another aspect, the present invention relates to the use of a torque impulse that can be generated by a drive of a power tool to loosen or tighten a fastening nut for fastening a disk-shaped tool to the power tool.

[0021] Further advantages will become apparent from the following description of the drawings. The drawings, description, and claims include a number of feature combinations. Those skilled in the art will also be able to consider the features individually, as appropriate, and combine them to form further useful combinations.

[0022] In the drawings, the same and similar components are designated with the same reference numbers. [Brief description of the drawings]

[0023] [Figure 1] 1 shows a preferred embodiment of the proposed power tool; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Fig. 1 shows a preferred embodiment of the proposed power tool (1). The proposed power tool (1) can be, for example, an angle grinder or a cut-off grinder. The power tool (1) comprises a disk-shaped tool (2), for example in the form of a cut-off disk or a grinding disk. The tool (2) is fastened to a drive shaft (4) of the power tool (1) by means of a fastening nut (3), whereby the drive shaft (4) of the power tool (1) is arranged to transmit the torque of the drive of the power tool (1) to the tool (2). The drive of the power tool (1) comprises in particular a motor (5), whereby in a preferred embodiment of the invention the drive can comprise a gearbox (11). The motor (5) is preferably a brushless motor, which can in particular be configured to be electronically commutated.

[0025] In the present invention, it is provided that the power tool (1) is installed to loosen or tighten the fastening nut (3) by the torque impulse of the drive part of the power tool (1). In other words, the fastening nut (3) can be loosened or tightened by the torque impulse of the drive part of the power tool (1). Fastening the fastening nut (3) preferably means in the present invention that the fastening nut (3) is fastened or fixed to the power tool (1). The tool (2) preferably interacts with a tool fixture (7) which is installed to receive the tool (2) and fasten it to the power tool (1). In the present invention, the tool fixture (7) can also be referred to as an output shaft.

[0026] In a preferred embodiment of the present invention, the power tool (1) may comprise at least one sensor (6) for monitoring the output of at least one torque impulse. The output of at least one torque impulse for releasing or fastening the tool (2) is preferably generated by using at least one sensor (6). This preferably means in the context of the present invention that the sensor (6) of the power tool (1) is arranged to monitor the output of at least one torque impulse leading to the release or fastening of the tool (2). The sensor (6) may in particular detect the position and / or the acceleration. In the context of the present invention, the at least one sensor (6) is preferably arranged between the motor (5) and the electronics (9). The at least one sensor (6) may in particular be connected to the motor (5) of the power tool (1) or be in its spatial vicinity.

[0027] The power tool (1) preferably comprises an operator control element (8) arranged to initiate the release or fastening of the tool (2) with the fastening nut (3), so that the user advantageously has the possibility to initiate the fastening or unfastening of the tool (2), preferably without assistance. The power tool (1) may also comprise electronics (9) arranged preferably for evaluating data determined by the at least one sensor (6), for evaluating inputs entered via the operator control element (8) and / or for controlling the motor (5) and its power supply. For this purpose, the power tool (1) may comprise electrical connections (10) arranged for connecting the operator control element (8), the electronics (9), the at least one sensor (6) and / or the motor (5). [Explanation of symbols]

[0028] 1 Power tools 2 Disc-shaped tools 3 Fastening nut 4 Drive shaft 5 Motor 6 Sensors 7 Tool Fixture 8 Operator Control Elements 9 Electronic equipment 10 Electrical Connections 11 Gearbox

Claims

1. An electric power tool (1) comprising a disk-shaped tool (2), the disk-shaped tool (2) being fastened to a drive shaft (4) of the electric power tool (1) by a fastening nut (3), and the drive shaft (4) transmitting torque of a drive section of the electric power tool (1) to the tool (2), The drive unit comprises a motor (5), the motor (5) being an electronically commutated motor; A sensorless feedback of the motor (5) is used to detect the angular change in the motor (5); The power tool (1) can loosen or tighten the fastening nut (3) by torque impulses outputted 1 to 10 times per second by the drive unit of the power tool (1). A power tool characterized by:

2. 2. The power tool according to claim 1, characterized in that the clamping nut (3) can be loosened or tightened unaided by at least one of the torque impulses of the drive part of the power tool (1).

3. 3. Power tool according to claim 1 or 2, characterized in that the power tool (1) comprises at least one sensor (6) for monitoring the torque impulses.

4. The power tool (1) according to any one of claims 1 to 3, characterized in that the power tool (1) comprises a tool attachment (7) for receiving the disk-shaped tool (2).

5. 4. The power tool according to claim 3, characterized in that the power tool (1) comprises an operator control element (8) for releasing or initiating tightening of the clamping nut (3) of the disk-shaped tool (2) by the torque impulse.

6. 6. The power tool according to claim 5, characterized in that the power tool (1) comprises electronics (9) for evaluating data determined by the at least one sensor (6), for evaluating inputs input via the operator control element (8) and / or for controlling the motor (5) and its power supply.

7. 7. The power tool according to claim 6, characterized in that the at least one sensor (6) is arranged between the motor (5) and the electronics (9).

8. 8. The power tool according to claim 6 or 7, characterized in that the power tool (1) comprises electrical connections (10) for connecting the operator control element (8), the electronics (9), the at least one sensor (6) and / or the motor (5).

Images