Portable, hand-held cutting machine

Abstract

Portable, hand-held cutting machine (10), comprising: - a supporting housing part (36), - an output shaft (20) which is rotatably mounted on the housing part (36) by means of a bearing element (45) about an output axis (40), - a drive motor (17) and a transmission device (19) which connects the drive motor (17) to the output shaft (20), wherein the transmission device (19) is arranged on the housing part (36), and wherein the drive motor is designed as an electric motor, - a flange (41) with a flange diameter (d f ), wherein a cutting-off wheel (11) can be arranged on the output shaft (20) in a rotationally fixed manner by means of the flange (41), and - a protective hood (24) with a covering region (25) which is designed to at least partially cover a cutting-off wheel (11), and a processing region (26) which is designed to expose a cutting-off wheel (11), wherein the protective hood (24) is mounted on the housing part (36) so as to be pivotable about a pivot axis (27), characterized in that the pivot axis (27) of the protective hood (24) is shifted from the output axis (40) of the output shaft (20) by a distance (Δ) and in that the pivot axis (27) is shifted relative to the output axis (40) into the covering region (25) of the protective hood (24).

Description

Technical area

[0001] The present invention relates to a portable, hand-held cutting machine according to the preamble of claim 1. State of the art

[0002] Cutting machines are portable, hand-held power tools with a processing tool in the form of a rotating cutting wheel. The essential components of a cutting machine include, in addition to the cutting wheel, a supporting housing, an output shaft mounted for rotation about an output axis, a drive motor, a transmission device connecting the drive motor to the output shaft, a flange, and a protective hood that covers the cutting wheel via a covering area. The cutting wheel is mounted on the output shaft in a rotationally fixed manner by means of the flange and is surrounded by the protective hood, which is mounted for rotation about a pivot axis. The pivot axis of the protective hood is arranged coaxially to the output axis, which corresponds to the rotation axis of the cutting wheel. DE 10 2005 049 766 B4 discloses such a portable, hand-held cutting machine.

[0003] The European standard EN ISO 19432:2012 and the US standard ANSI B175.4-2013 specify safety requirements and design verification measures for portable, hand-held, internal combustion engine-powered cut-off machines for one-person operation, designed for cutting construction materials such as asphalt, concrete, stone, and metal. They apply to cut-off machines designed for use with a rotating cut-off wheel with bonded abrasives and / or diamond and CBN abrasives, centrally mounted on and driven by a spindle shaft, with the face of the cut-off wheel rotating in a direction away from the operator. The standards define a minimum flange diameter for the flange, depending on the type and diameter of the cut-off wheel.A distinction is made between diamond cutting wheels and abrasive cutting wheels, and four ranges are distinguished for the wheel diameter D of the cutting wheels (D ≤ 250 mm, 250 mm < D ≤ 300 mm, 300 mm < D ≤ 350 mm, and 350 mm < D). The European standard EN ISO 19432:2012 applies to cutting wheels with a maximum wheel diameter of 400 mm, and the US standard ANSI B175.4-2013 applies to cutting wheels with a maximum wheel diameter of 406 mm.

[0004] The European standard EN IEC 60745-2-22:2011 and the US standard ANSI / UL 60745-2-22-2012 apply to hand-held, motor-driven power tools in the form of cutting-off machines intended for cutting materials such as metal, concrete, masonry, glass, and tiles using a rotating cutting-off wheel with wheel diameters from 55 mm to 410 mm. The standards define a minimum flange diameter for the flange depending on the type, wheel diameter D, and bore diameter Ø of a cutting-off wheel. Regarding the type of cutting-off wheel, a distinction is made between diamond cutting-off wheels and bonded reinforced cutting-off wheels of type 41 or 42. The minimum flange diameter d min is d min= 0.15 * D for diamond cutting wheels with a wheel diameter D of 55 mm ≤ D ≤ 410 mm. For bonded reinforced cutting wheels of type 41 or 42, four ranges are distinguished for the wheel diameter D (55 mm ≤ D < 80 mm, 80 mm ≤ D < 105 mm, 105 mm ≤ D ≤ 230 mm and 230 mm < D ≤ 410 mm) and for wheel diameter D with 80 mm ≤ D < 105 mm, bore diameters Ø of 10 mm and 16 mm are distinguished.

[0005] The maximum cutting depth that a cutting wheel can achieve in a workpiece is determined by half the difference between the wheel diameter of the cutting wheel and the associated minimum flange diameter of the flange. In practice, diamond cutting wheels with wheel diameters of 300 mm and 350 mm are primarily used in cutting machines with an internal combustion engine. The maximum cutting depth that a diamond cutting wheel with a wheel diameter of 300 mm can achieve is 127.5 mm, and the maximum cutting depth that a diamond cutting wheel with a wheel diameter of 350 mm can achieve is 148.75 mm.

[0006] The actual cutting depths achieved by conventional cut-off machines in a workpiece are less than the stated maximum cutting depths, which are determined by half the difference between the disc diameter and the minimum flange diameter. The equipment manufacturer Stihl offers various cut-off machines with combustion engines, including the TS 400, TS 410, and TS 420 cut-off machines. The TS 400 cut-off machines are designed for diamond cut-off wheels and can be operated with different disc diameters of 300 mm and 350 mm. According to the manufacturer, the cutting depth achieved by the TS 400 cut-off machine with a disc diameter of 300 mm is 100 mm, and the maximum cutting depth achieved by the TS 400 cut-off machine with a disc diameter of 350 mm is 125 mm.The TS 410 cutting machines are designed for diamond cutting wheels with a wheel diameter of 300 mm, and the TS 420 cutting machines are designed for diamond cutting wheels with a wheel diameter of 350 mm. According to the manufacturer, the maximum cutting depth achieved by the TS 410 cutting machine is 100 mm, and the maximum cutting depth achieved by the TS 420 cutting machine is 125 mm.

[0007] The cutting depths achieved by the TS 400 cut-off machine with a 300 mm disc diameter and the TS 410 cut-off machine are 20% less than the maximum cutting depth of 127.5 mm, and the cutting depths achieved by the TS 400 cut-off machine with a 350 mm disc diameter and the TS 420 cut-off machine are approximately 16% less than the maximum cutting depth of 148.75 mm. The flanges used by Stihl on the TS 400, TS 410, and TS 420 cut-off machines have a flange diameter of at least 103 mm. For the TS 400 cut-off machines, which can be operated with different disc diameters of 300 mm and 350 mm, the same flange diameter of at least 103 mm is required for the different disc diameters. The flange diameters used are much larger than the minimum flange diameters d min, which covers the European standard EN ISO 19432:2012 and the US standard ANSI B175.4-2013 for diamond cutting wheels with a wheel diameter of 300 mm (d min ≥ 45 mm) and a disc diameter of 350 mm (d min ≥ 52.5 mm). The standards apply to cutting-off machines manufactured on or after the publication date of the standards and not to cutting-off machines manufactured before the publication date of the standards. Previous versions of the standards also specified the same minimum flange diameters of 45 mm and 52.5 mm for diamond cutting wheels with wheel diameters of 300 mm and 350 mm. Description of the invention

[0008] The object of the present invention is to further develop a portable, hand-held cutting machine in such a way that the cutting depth that can be achieved with a cutting wheel in a workpiece is increased compared to the known cutting machines and, if possible, the maximum cutting depth, which is determined by half the difference between the wheel diameter of the cutting wheel and the minimum flange diameter of the flange, is achieved.

[0009] This object is achieved according to the invention in the portable, hand-held cutting machine mentioned above by the features of independent claim 1. Advantageous further developments are specified in the dependent claims.

[0010] According to the invention, the portable, hand-held cutting machine is characterized in that the pivot axis of the protective hood is offset from the output axis of the output shaft by a certain distance. With a protective hood that is designed to pivot about a pivot axis, an additional bearing element is required for pivotally supporting the protective hood. By shifting the pivot axis relative to the output axis, the components of the cutting machine arranged in the area of ​​the output shaft can be better distributed within the available space, thereby increasing the cutting depth. The components arranged in the area of ​​the output shaft include a bearing for the output shaft, the protective hood, the supporting housing part, and the transmission device.

[0011] The cutting depth that a cutting wheel can achieve in a workpiece is determined by half the difference between the wheel diameter of the cutting wheel used and the flange diameter of the flange used. This cutting depth is only achieved if no components of the cutting machine additionally limit the cutting depth. The protective hood consists of the covering area that covers the cutting wheel and the processing area that releases the cutting wheel for processing a workpiece. In the processing area of ​​the protective hood, the flange with the flange diameter defines a receiving area that is available for the arrangement and storage of the components (protective hood, supporting housing part and transmission device).If the cutting machine is to achieve the cutting depth determined by half the difference between the disc diameter of the cutting wheel used and the flange diameter of the flange used, all components of the cutting machine must be moved into the mounting area over a limited angular range.

[0012] To increase the cutting depth of a cutting wheel, a flange with the smallest possible flange diameter is used. The smaller the flange diameter, the smaller the area for arranging and supporting the components. Therefore, optimal arrangement of the components is particularly important if the smallest possible flange diameter is to be used. The mounting of the protective hood is particularly critical. The protective hood has a mounting flange that is connected to one side wall of the protective hood. The mounting flange is placed on a matching mating contour of the supporting housing part and is designed to be adjustable about the pivot axis to the mating contour. If the pivot axis of the protective hood coincides with the output axis of the output shaft, the diameter of the mounting flange is limited by the flange diameter.By shifting the swivel axis, the diameter of the mounting flange can be selected to be larger than the flange diameter.

[0013] Particularly preferably, the pivot axis of the protective hood is shifted relative to the output axis of the output shaft into the cover area of ​​the protective hood. The protective hood consists of the cover area, which covers the cutting-off wheel, and the machining area, which exposes the cutting-off wheel for machining a workpiece. In order to achieve the greatest possible cutting depth with a cutting-off wheel, a flange with the smallest possible flange diameter is used. The smaller the flange diameter selected, the smaller the mounting area for the arrangement and bearing of the components (bearing for the output shaft, protective hood, supporting housing part and transmission device), with the bearing of the protective hood being particularly critical. The diameter of the mounting flange is a size which, in the case of pivoting protective hoods that are adjustable via frictional engagement, is essentially determined by the size and weight of the protective hood.By shifting the swivel axis into the cover area of ​​the protective hood, the diameter of the mounting flange can be selected to be larger than the flange diameter of the flange used.

[0014] Particularly preferably, the protective hood has a mounting flange with a diameter, and the distance between the pivot axis and the output axis is greater than or equal to half the difference between the diameter of the mounting flange and the flange diameter. The mounting flange is the component of the protective hood over which the protective hood is designed to pivot. The mounting flange is attached to a matching mating contour of the supporting housing part and is designed to be adjustable relative to the mating contour about the pivot axis. The diameter of the mounting flange is a value that is essentially determined by the size and weight of the protective hood.If the distance between the swivel axis and the output axis is selected to be greater than or equal to half the difference between the diameter of the mounting flange and the flange diameter, the mounting flange of the protective hood is located at the outcut angle within the receiving area defined by the flange with the flange diameter.

[0015] In a preferred embodiment, the protective hood, the supporting housing part, and the transmission device have maximum distances from the output axis across an outcut angle that are less than half the flange diameter or equal to half the flange diameter. The outer boundaries of the components of the cut-off machine, which are designed as the protective hood, supporting housing part, and transmission device, are referred to as outer contours, and the distances from the output axis correspond to the maximum distances of the outer contours from the output axis at the outcut angle; outside the outcut angle, the distances of the outer contours from the output axis are greater than or equal to half the flange diameter.Because the outer contours of the cut-off machine's components are designed at the outcut angle so that their distances from the output axis are less than or equal to half the flange diameter, the cutting depth determined by half the difference between the disc diameter and the flange diameter can be achieved at the outcut angle. The cutting depth of the cut-off machine according to the invention is increased at the outcut angle compared to known cut-off machines.

[0016] The transmission device preferably has an output pulley arranged on the output shaft and a transmission element that transmits a movement of the drive motor to the output pulley, wherein the output pulley and the transmission element have maximum distances from the output axis across the outcut angle that are less than or equal to half the flange diameter. The transmission device is one of the components of the cut-off machine arranged at the outcut angle. The condition that the maximum distance of the transmission device from the output axis at the outcut angle is less than or equal to half the minimum flange diameter must be met for all subcomponents of the transmission device. This includes the output pulley arranged on the output shaft and the transmission element arranged on the output pulley.The output pulley has a fourth maximum distance from the output axis and the transmission element has a fifth maximum distance from the output axis.

[0017] Particularly preferably, the transmission device has a cover, wherein the cover has a maximum distance from the output axis across the outcut angle that is less than or equal to half the flange diameter. The subcomponents of the transmission device, which are designed as an output disk and transmission element, are rotating components that must be covered for safety reasons. The cover has a sixth maximum distance from the output axis.

[0018] In a preferred further development of the cutting-off machine according to the invention, the flange diameter of the flange corresponds to a minimum flange diameter. The minimum flange diameter is defined as the flange diameters specified in the applicable standards as lower limits for the flange. The minimum flange diameter depends, among other things, on the type of drive motor, the type of cutting-off wheel, and the diameter of the cutting-off wheel. If the flange diameter of the flange used corresponds to the minimum flange diameter, the maximum cutting depth can be achieved with a cutting-off wheel, whereby the maximum cutting depth of a cutting-off wheel is determined by half the difference between the diameter of the cutting-off wheel and the minimum flange diameter.The cutting machine according to the invention has the advantage of increasing the cutting depth compared to known cutting machines, thus achieving the maximum cutting depth. With a disc diameter of 300 mm, the cutting machine according to the invention with a combustion engine and a diamond cutting disc achieves a cutting depth that requires a diamond cutting disc with a disc diameter of 350 mm for known cutting machines with combustion engines, such as the TS 400 and TS 410 cutting machines from Stihl.

[0019] In a preferred first variant of the cutting-off machine according to the invention, the drive motor is designed as an internal combustion engine, and the cutting-off wheel is designed as a diamond cutting-off wheel or an abrasive cutting-off wheel. For cutting-off machines with internal combustion engines, the European standard EN ISO 19432:2012 applies in Europe, and the US standard ANSI B175.4-2013 applies in the USA. Comparable standards apply in other countries or regions outside Europe and the USA, and in European countries, the European standard may be implemented as national standards. The minimum flange diameter d min is for cutting-off machines according to the invention with an internal combustion engine and a diamond cutting wheel: d min = 37.5 mm for D ≤ 250 mm, d min = 45 mm for 250 mm < D ≤ 300 mm, d min = 52.5 mm for 300 mm < D ≤ 350 mm and d min = 60 mm for 350 mm < D. The minimum flange diameter d minis for cutting machines with an internal combustion engine and an abrasive cutting wheel: d min = 63.5 mm for D ≤ 250 mm, d min = 75 mm for 250 mm < D ≤ 300 mm, d min = 87.5 mm for 250 mm < D ≤ 350 mm and d min = 100 mm for 350 mm < D.

[0020] A cutting-off machine according to the invention with an internal combustion engine and a diamond cutting-off wheel achieves a maximum cutting depth of 106.25 mm (½ * (250 mm - 37.5 mm)) with a wheel diameter of 250 mm, a maximum cutting depth of 127.5 mm (½ * (300 mm - 45 mm)) with a wheel diameter of 300 mm, a maximum cutting depth of 148.75 mm (½ * (350 mm - 52.5 mm)) with a wheel diameter of 350 mm and a maximum cutting depth of 170 mm (½ * (400 mm - 60 mm)) with a wheel diameter of 400 mm. A cutting-off machine according to the invention with an internal combustion engine and an abrasive cutting-off wheel achieves a maximum cutting depth of 93.25 mm (½ * (250 mm - 63.5 mm)) with a wheel diameter of 250 mm, a maximum cutting depth of 112.5 mm (½ * (300 mm - 75 mm)) with a wheel diameter of 300 mm, and a maximum cutting depth of 131.25 mm (½ * (350 mm - 87.5 mm)) and with a disc diameter of 400 mm a maximum cutting depth of 150 mm (½ * (400 mm - 100 mm)).

[0021] In a preferred second variant of the cutting-off machine according to the invention, the drive motor is designed as an electric motor, and the cutting-off wheel is designed as a diamond cutting-off wheel or as a bonded reinforced cutting-off wheel of type 41 or 42. For cutting-off machines with electric motors, the European standard EN IEC 60745-2-22:2011 applies in Europe, and the US standard ANSI / UL 60745-2-22-2012 applies in the USA. Comparable standards apply in other countries or regions outside Europe and the USA, and in European countries, the European standard may be implemented as national standards. The minimum flange diameter d min is for cutting-off machines according to the invention with an electric motor and a diamond cutting wheel: d min = 0.15 * D for 55 mm ≤ D ≤ 410 mm. The minimum flange diameter d minis for cutting-off machines according to the invention with an electric motor and a bonded reinforced cutting-off wheel of type 41 or 42: d min = 19 mm for 55 mm ≤ D < 80 mm, d min = 19 mm at Ø = 10 mm and d min = 28 mm at Ø = 16 mm for 80 mm ≤ D < 105 mm, d min = 40 mm for 105 mm ≤ D ≤ 230 mm and d min = 0.25 * D for 230 mm < D ≤ 410 mm. Examples of implementation

[0022] Embodiments of the invention are described below with reference to the drawing. These are not necessarily intended to show the embodiments to scale; rather, where useful for explanation, the drawing is schematic and / or slightly distorted. It should be noted that many modifications and changes to the form and detail of an embodiment can be made without deviating from the general idea of ​​the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiment shown and described below, or to an object that would be limited compared to the object claimed in the claims. For given dimensioning ranges, values ​​lying within the stated limits are also intended to be disclosed as limit values ​​and can be used and claimed as desired.For the sake of simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar functions.

[0023] They show: Fig. 1A, B a portable, hand-held cutting machine according to the invention with a cutting wheel; Fig. 2A, B a protective cover and a belt drive in Fig. 1A, B shown cutting machine with a cover ( Fig. 2A) and without cover ( Fig. 2B); Fig. 3A-C the cutting disc and the protective hood of the cutting machine of the Fig. 1A in a side view ( Fig. 3A) and in a first section along the section line AA ( Fig. 3B) and in a second section along the section line BB ( Fig. 3C); Fig. 4 an enlarged section of the second section of the Fig. 3C; and Fig. 5 the protective hood and a support arm housing of the belt drive, whereby the cutting depth corresponds to the maximum cutting depth via an outcut angle.

[0024] Fig. 1A, B show a portable, hand-held tool 10 according to the invention, which is designed in the form of a cutting-off machine. The cutting-off machine 10 has a processing tool designed as a cutting-off wheel 11, which is driven by a drive device 12 in a direction of rotation 13 about a rotational axis 14. In this case, all drive components for the cutting-off wheel 11 are combined as the drive device 12. In the Fig. In the cut-off machine 10 shown in Figure 1B, a cover 15 has been removed so that at least some drive components of the drive device 12 are visible. The cover 15 can be formed as a single piece or in multiple pieces and is attached to the cut-off machine 10 by screws.

[0025] The drive device 12 comprises a drive motor 17 arranged in a motor housing 16, a transmission device arranged in a support arm 18, which is designed as a belt drive 19, and an output shaft 20 on which the cutting-off wheel 11 is mounted. If necessary, additional transmission components can be connected between the drive motor 17 and the belt drive 19. A centrifugal clutch can be arranged between the drive motor 17 and the belt drive 19, which ensures that the cutting-off wheel 11 does not rotate at low speeds, such as when idling or when starting the cut-off machine 10. The centrifugal clutch has a clutch bell against which centrifugal weights are pressed outwards during operation due to centrifugal force. The drive motor 17 drives a drive shaft 21 about a drive axis 22.The clutch bell of the centrifugal clutch is connected in a rotationally fixed manner to a drive disc 23 which is rotatably mounted on the drive shaft 21.

[0026] Internal combustion engines or electric motors are used as drive motors 17 for the cut-off machine 10. The term "electric motor" encompasses all drive motors for motor-driven power tools, whereby the power tools can be wired with a direct connection to the power grid or wired without a direct connection to the power grid. Cut-off machines with an internal combustion engine can be used with various types of cut-off wheels 11, diamond cut-off wheels and abrasive cut-off wheels, whereby the cut-off wheels comprise cut-off wheels made of bonded abrasives and / or grinding tools with diamond and CBN abrasives. Cut-off machines with an electric motor can be used with various types of cut-off wheels 11, diamond cut-off wheels and bonded reinforced cut-off wheels of type 41 or 42.

[0027] The cutting-off wheel 11 is surrounded by a protective hood 24, which serves to protect the operator from flying dust particles and also reduces the risk of injury if the operator reaches into the rotating cutting-off wheel 11 during operation of the cutting-off machine 10. The protective hood 24 is fastened in a hub area of ​​the cutting-off wheel 11 and consists of a covering area 25, which covers the cutting-off wheel 11 over a covering angle of approximately 200°, and a processing area 26, which exposes the cutting-off wheel 11 over a processing angle of approximately 160° for processing a workpiece. The protective hood 24 is pivotable and can be rotated about a pivot axis 27 ( Fig. 2A, B) into a desired pivoting position. To adjust the pivoting position, a grip element 28 is attached to the protective hood 24, with which the necessary forces can be applied to pivot the protective hood 24 about the pivot axis 27.

[0028] To operate the cutting machine 10, a first handle 31 is provided, which has an operating device 32 and is designed as a top handle. A top handle is a handle that is arranged above the motor housing 16. Alternatively, the first handle can be designed as a rear handle, which is arranged on the side of the motor housing 16 facing away from the cutting wheel 11. To guide the cutting machine 10, in addition to the first handle 31, a second handle 33 is provided, which is arranged between the cutting wheel 11 and the first handle 31. The second handle 33 is in the Fig. 1A, B, is designed as a separate handle tube or can alternatively be designed as one piece with the motor housing 16 or another housing part.

[0029] Fig. 2A, B show the protective hood 24 and the belt drive 19 of the cutting machine 10 of the Fig. 1A, B in an enlarged view. The belt drive 19 is arranged in a support arm housing 35, which comprises a fixed supporting housing part 36 and the cover 15. Fig. 2A shows the belt drive 19 with mounted cover 15 and Fig. 2B the belt drive 19 without cover 15.

[0030] The cutting-off wheel 11 is driven via the drive motor 17, the belt drive 19, and the output shaft 20. The drive motor 17 can be designed as an internal combustion engine or as an electric motor. The drive motor 17 drives the drive shaft 21 and the drive pulley 23 about the drive axis 22. A transmission element 38 designed as a drive belt is guided over the drive pulley 23 and an output pulley 39 mounted on the output shaft 20. The output shaft 20 is rotatable about an output axis 40, which coincides with the axis of rotation 14 of the cutting-off wheel 11. The drive pulley 23, the drive belt 38, and the output pulley 39 form the belt drive 19. The transmission device 19 can alternatively be designed, for example, in the form of a chain drive, in which the transmission element between the drive pulley 23 and the output pulley 39 is designed as a chain.The cutting wheel 11 is arranged on the output shaft 20 by means of a flange 41 and is connected to the output shaft 20 in a rotationally fixed manner. The flange 41 and the cutting wheel 11 are mounted on the output shaft 20, and the cutting wheel 11 is arranged between two flange halves of the flange 41.

[0031] The machining of a workpiece with the cut-off machine 10 takes place in the area of ​​the cut-off wheel 11, which lies in the processing area 26 of the protective hood 24. The protective hood 24 has a fastening flange 42 in the hub area of ​​the cut-off wheel 11, which in the exemplary embodiment is formed integrally with a side wall 43 of the protective hood 24; alternatively, the fastening flange can be formed as a separate part and connected to the protective hood 24. The fastening flange 42 is attached to a matching mating contour 44 of the fixed housing part 36 and is designed to be adjustable relative to the mating contour 44 of the housing part 36. The protective hood 24 is designed to be pivotable about the pivot axis 27 between a front pivot position and a rear pivot position. The pivoting range of the protective hood 24 is limited to an angular range of approximately 60°.

[0032] Fig. 3A-C show the cutting-off wheel 11 and the protective cover 24 of the cutting-off machine 10 of the Fig. 1A in an enlarged view. Fig. 3A the arrangement of cutting wheel 11 and protective hood 24 in a side view, Fig. 3B a section along the section line AA in Fig. 3A and Fig. 3C a section along the section line BB in Fig. 3A. The cutting wheel 11 is mounted on the output shaft 20 by means of the flange 41 and is designed to rotate about the rotational axis 14. The movement of the drive motor 17 is transmitted to the output shaft 20 via the drive belt 38 and the output pulley 39, which is mounted on the output shaft 20 in a rotationally fixed manner.

[0033] The protective hood 24 consists of the covering area 25, which covers the cutting-off wheel 11, and the processing area 26, which exposes the cutting-off wheel 11 for processing a workpiece. The full angle of the cutting-off wheel 11 of 360° is divided by the protective hood 24 into a covering angle and a processing angle. The covering area 25 of the protective hood 24 determines the covering angle, and the processing area 26 of the protective hood 24 determines the processing angle. In the illustrated example, the covering angle is approximately 200° and the processing angle is approximately 160°.

[0034] The output shaft 20 is mounted on the stationary housing part 36 via a bearing element 45. The protective cover 24 is attached to the stationary housing part 36. The mounting flange 42 of the protective cover 24 is placed on the counter-contour 44 of the housing part 36 and is designed to pivot relative to the stationary housing part 36 about the pivot axis 27. To facilitate the pivoting movement of the protective cover 24, a sliding element 46 is provided between the mounting flange 42 and the counter-contour 44. This sliding element reduces friction and is designed, for example, as a Teflon ring.

[0035] Fig. 3C shows the pivot axis 27 of the protective cover 24, which is different from the output axis 40 of the output shaft 20. The pivot axis 27 is offset from the output axis 40 into the cover area 25 of the protective cover 24. In the illustrated embodiment, the distance Δ between the pivot axis 27 and the output axis 40 is greater than half the diameter d of the output shaft 20.

[0036] Fig. 4 shows an enlarged section of the Fig. 3C shown second section along the section line BB in Fig. 3A. The section shows the output shaft 20 and the flange 41 with which the cutting wheel 11 is attached to the output shaft 20.

[0037] The flange 41 is constructed in several parts and comprises a first flange part 51, a second flange part 52, and a tool screw 53. To mount the cutting-off wheel 11, the first flange part 51 is pushed or screwed onto the output shaft 20, the cutting-off wheel 11 is pushed onto the first flange part 51, and the second flange part 52 is mounted. The cutting-off wheel 11 is clamped between the first and second flange halves 51, 52 by means of the tool screw 53.

[0038] For cutting-off machines with a combustion engine, the European standard EN ISO 19432:2012, the US standard ANSI B175.4-2013 and corresponding standards in other countries define a minimum flange diameter d for the flange 41 depending on the type of cutting-off wheel 11 (diamond cutting-off wheel or abrasive cutting-off wheel) and the wheel diameter D of the cutting-off wheel 11 (D ≤ 250 mm, 250 mm < D ≤ 300 mm, 300 mm < D ≤ 350 mm and 350 mm < D). min . The minimum flange diameter d min is for diamond cutting wheels: d min = 37.5 mm for D ≤ 250 mm, d min = 45 mm for 250 mm < D ≤ 300 mm, d min = 52.5 mm for 300 mm < D ≤ 350 mm and d min = 60 mm for 350 mm < D. The minimum flange diameter d min is for abrasive cutting wheels: d min = 63.5 mm for D ≤ 250 mm, d min = 75 mm for 250 mm < D ≤ 300 mm, d min = 87.5 mm for 300 mm < D ≤ 350 mm and d min= 100 mm for 350 mm < D.

[0039] The maximum cutting depth t max , which the cutting wheel 11 can achieve in a workpiece, is achieved when the flange diameter d f of the flange 41 the minimum flange diameter d min and no components of the cutting machine 10 additionally limit the cutting depth. The maximum cutting depth t max by half the difference between the wheel diameter D of the cutting wheel 11 and the minimum flange diameter d min of flange 41 defined: t max = ½ * (D - d min ). The maximum cutting depth t max is for cutting machines 10 with combustion engine and a diamond cutting wheel: t max = 106.25 mm for D = 250 mm, t max = 127.5 mm for D = 300 mm, t max = 148.75 mm for D = 350 mm and t max = 170 mm for D = 400 mm. The maximum cutting depth t maxFor cutting machines with combustion engines and an abrasive cutting wheel, the value is: t max = 93.25 mm for D = 250 mm, t max = 112.5 mm for D = 300 mm, t max = 131.25 mm for D = 350 mm and t max = 150 mm for D = 400 mm.

[0040] The cutting cuts t of the cutting wheel 11 is determined in addition to the flange diameter d f of the flange 41 is determined by the outer contours of the components of the cut-off machine 10 in the processing area 26 of the protective hood 24. The outer contours include a first outer contour 54 of the protective hood 24, a second outer contour 55 of the supporting housing part 36 and a third outer contour 56 of the belt drive 19. The outer contours 54, 55, 56 are designed such that their maximum distances b to the output axis 40 are at an outcut angle θ less than or equal to half the minimum flange diameter d minThe first outer contour 54 of the protective hood 24 has a first maximum distance b1 from the output axis 40 at the outcut angle, the second outer contour 55 of the supporting housing part 36 has a second maximum distance b2 from the output axis 40 at the outcut angle, and the third outer contour 56 of the belt drive 19 has a third maximum distance b3 from the output axis 40 at the outcut angle. The maximum distance b of a component is defined as the maximum distance of the outer contour from the output axis 40 at the outcut angle θ.

[0041] The condition that the maximum distance b3 of the belt drive 19 to the output shaft 40 is less than or equal to half the minimum flange diameter d minmust apply to all subcomponents of the belt drive 19 at the outcut angle θ. The belt drive 19 consists in the area of ​​the output shaft 20 of the output pulley 39, the drive belt 38 and the cover 15. The output pulley 39 has a fourth maximum distance b4 from the output axis 40 at the outcut angle θ, the drive belt 38 has a fifth maximum distance b5 from the output axis 40 at the outcut angle θ and the cover 15 has a sixth maximum distance b6 from the output axis 40 at the outcut angle θ.

[0042] Since the drive belt 38 is arranged on the driven pulley 39 and in the exemplary embodiment the driven pulley 39 does not protrude from the drive belt 38, the fourth maximum distance b4 of the driven pulley 39 to the output shaft 40 in the outcut angle is smaller than the fifth maximum distance b5 of the drive belt 38. If the condition that the maximum distance in the outcut angle θ is less than or equal to half the minimum flange diameter d min is fulfilled for the drive belt 38, the condition is also fulfilled for the driven pulley 39. For any design of the driven pulley 39 and the drive belt 38, the condition that the maximum distance in the outcut angle θ is less than or equal to half the minimum flange diameter d min is fulfilled for the driven pulley 39 and the drive belt 38.

[0043] The cover 15 has the task of covering the belt drive 19 and covers the driven pulley 39 and the drive belt 38 in the area of ​​the output shaft 20. In the exemplary embodiment, the driven pulley 39 and the drive belt 38 are completely covered by the cover 15. If the condition that the maximum distance in the outcut angle θ is less than or equal to half the minimum flange diameter d min is fulfilled for the cover 15, the condition is also fulfilled for the driven pulley 39 and the drive belt 38. The third maximum distance b3 of the belt drive 19 to the output shaft 40 corresponds in the exemplary embodiment to the sixth maximum distance b6 of the cover 15 to the output shaft 40. For any design of the driven pulley 39, the drive belt 38 and the cover 15, the condition that the maximum distance in the outcut angle is less than or equal to half the minimum flange diameter d minfor the cover 15, the driven pulley 39 and the drive belt 38.

[0044] Fig. 5 shows the protective hood 24 of the cutting-off machine 10 without the cutting-off wheel 11 in a pivoting position which corresponds to the pivoting position of the protective hood 24 in Fig. 3A. The protective cover 24 is pivotably mounted on the fixed housing part 36 by means of the fastening flange 42 about the pivot axis 27. The fastening flange 42 is circular and has a diameter d x The diameter d x of the fastening flange 42 a size which is essentially determined by the size and weight of the protective hood 24.

[0045] The pivot axis 27 of the protective hood 24 is different from the output axis 40 of the output shaft 20. The pivot axis 27 is offset relative to the output axis 40 into the cover area 25 of the protective hood 24. The full angle of the cutting-off wheel 11 of 360° is divided by the protective hood 24 into the cover angle and the processing angle, with the cover angle being approximately 200° and the processing angle approximately 160°. The outcut angle θ lies within the processing angle of the cutting-off wheel 11 and is approximately 70° in the exemplary embodiment.

[0046] The mounting of the protective cover 24 at the outcut angle θ is particularly critical due to the limited mounting area. The protective cover 24 has a mounting flange 42, which is attached to the mating contour 44 of the supporting housing part 36. If the pivot axis 27 of the protective cover 24 coincides with the output axis 40 of the output shaft 20, the diameter d xof the mounting flange 42 by the flange diameter d f The smaller the flange diameter d f selected, the smaller the area for arranging and storing the components. If the flange diameter d f of the flange 41 the minimum flange diameter d min corresponds, the smallest space is available for the arrangement and storage of the components.

[0047] By shifting the pivot axis 27 into the cover area 25 of the protective hood 24, the diameter d x of the mounting flange 42 larger than the flange diameter d f of the inserted flange 41. The distance Δ between the pivot axis 27 and the output axis 40 is greater than or equal to half the difference between the diameter d x of the mounting flange 42 and the flange diameter d fIn this case, the mounting flange 42 of the protective cover 24 is located in the receiving area defined by the flange diameter d f is defined. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2005 049 766 B4

[0002] Cited non-patent literature

[0000] EN ISO 19432:2012 [0003, 0007, 0019] ANSI B175.4-2013 [0003, 0007, 0019] EN IEC 60745-2-22:2011 [0004, 0021] ANSI / UL 60745-2-22-2012 [0004, 0021]

Claims

[1] Portable, hand-held cutting machine (10), comprising: - a supporting housing part (36), - an output shaft (20) which is rotatably mounted on the housing part (36) by means of a bearing element (45) about an output axis (40), - a drive motor (17) and a transmission device (19) which connects the drive motor (17) to the output shaft (20), wherein the transmission device (19) is arranged on the housing part (36), and wherein the drive motor is designed as an electric motor, - a flange (41) with a flange diameter (d f ), wherein a cutting-off wheel (11) can be arranged on the output shaft (20) in a rotationally fixed manner by means of the flange (41), and - a protective hood (24) with a covering area (25) which is designed to at least partially cover a cutting-off wheel (11), and a processing area (26) which is designed to expose a cutting-off wheel (11), wherein the protective hood (24) is pivotally mounted on the housing part (36) about a pivot axis (27), characterized by that the pivot axis (27) of the protective hood (24) is shifted from the output axis (40) of the output shaft (20) by a distance (Δ) and that the pivot axis (27) is shifted relative to the output axis (40) into the cover area (25) of the protective hood (24). [2] Cutting machine according to claim 1, characterized by that the protective hood (24) has a fastening flange (42) with a diameter (d x ) and the distance (Δ) between the pivot axis (27) and the output axis (40) is greater than or equal to half the difference between the diameter (d x) of the mounting flange (42) and the flange diameter (d f ) is. [3] Cutting machine according to one of claims 1 to 2, characterized by that the protective hood (24) has a first maximum distance (b1), the supporting housing part (36) has a second maximum distance (b2) and the transmission device (19) has a third maximum distance (b3) from the output axis (40) over an outcut angle (θ), wherein the first, second and third maximum distances (b1, b2, b3) are smaller than half the flange diameter (d f ) or equal to half the flange diameter (d f ) are. [4] Cutting machine according to claim 3, characterized bythat the transmission device (19) has an output pulley (39) which is arranged on the output shaft (20), and a transmission element (38) which transmits a movement of the drive motor (17) to the output pulley (39), wherein the output pulley (39) has a fourth maximum distance (b4) and the transmission element (38) has a fifth maximum distance (b5) from the output axis (40) over the outcut angle (θ), wherein the fourth and fifth maximum distances (b4, b5) are less than half the flange diameter (d f ) or equal to half the flange diameter (d f ) are. [5] Cutting machine according to claim 4, characterized by that the transmission device (19) has a cover (15), wherein the cover (15) has a sixth maximum distance (b6) from the output axis (40) over the outcut angle (θ), which is less than half the flange diameter (d f ) or equal to half the flange diameter (d f ) is. [6] Cutting machine according to one of claims 1 to 5, characterized by that the flange diameter (d f ) of the flange (41) a minimum flange diameter (d min ), where the minimum flange diameter (d min ) depends on the type of drive motor (17) and on the type, disc diameter (D) and bore diameter (Ø) of the cutting-off wheel (11). [7] Cutting-off machine according to one of claims 1 to 6, wherein the protective hood has a fastening flange (42) over which the protective hood (24) is designed to be pivotable, and wherein the fastening flange (42) is fitted onto a counter-contour (44) of the supporting housing part (36) and is designed to be pivotable about the pivot axis (27) relative to the supporting housing part (36). [8] Cutting-off machine according to one of claims 1 to 7, wherein the protective hood has a fastening flange (42) over which the protective hood (24) is designed to be pivotable, and wherein the fastening flange (42) has a diameter (d x ) which is larger than the flange diameter (d f ) of the flange (41). [9] Cutting-off machine according to claim 7 or 8, wherein the fastening flange (42) is arranged in the hub region of the cutting-off wheel (11). [10] Cutting machine according to one of claims 1 to 9, wherein the transmission device comprises a belt drive (19) which is arranged in a support arm housing (35), and wherein the support arm housing (35) comprises the supporting housing part (36) and a cover (15). [11] Cutting-off machine according to one of claims 1 to 10, wherein the cutting-off machine has a cutting-off wheel (11) with a wheel diameter (D).

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