Cover and cutting or grinding wheel tool

Abstract

The invention relates to a cover for a cutting or grinding disc, having a circumferential wall which extends parallel to the circumference of the cutting or grinding disc at least in some parts and at least along part of the circumference of the cutting or grinding disc, wherein at least one opening for the inlet of particles which have been detached from or by means of the cutting or grinding disc is provided in the circumferential wall, and a labyrinth structure adjoins the opening such that particles passing through the opening strike delimiting walls of the labyrinth structure multiple times and rebound again.

Description

[0001] Cover and cutting or grinding wheel tool

[0002] The invention relates to a cover for a cutting or grinding wheel and a cutting or grinding wheel tool.

[0003] Known guards for a cutting or grinding disc have a circumferential wall that extends at least partially parallel to one circumference of the cutting or grinding disc and at least along a portion of that circumference. Guards for cutting or grinding discs are intended to protect the operator, for example, an angle grinder operator from flying sparks. Sparks generated when working with a cutting or grinding disc tool can also be extremely dangerous, as they can start fires. Furthermore, the sparks, which are essentially glowing particles released from either the cutting or grinding disc or the workpiece, cause significant contamination and / or dust in a work area.

[0004] The invention aims to improve a cover for a cutting or grinding wheel and a cutting or grinding wheel tool.

[0005] According to the invention, a cover for a cutting or grinding wheel with the features of claim 1 and a cutting or grinding wheel tool with the features of claim 11 are provided. Advantageous embodiments of the invention are mentioned in the dependent claims.

[0006] A cover for a cutting or grinding disc with a circumferential wall extending at least sectionally parallel to a circumference of the cutting or grinding disc and at least along a part of a circumference of the cutting or grinding disc, has at least one opening in the circumferential wall for the inlet of particles that have been detached from or by means of the cutting or grinding disc, wherein a labyrinth structure adjoins the opening, so that particles passing through the opening repeatedly hit boundary walls of the labyrinth structure and rebound.

[0007] By connecting a labyrinth structure to the opening, the glowing particles, as well as any non-glowing particles, are guided onto the walls of the labyrinth structure, where they are repeatedly deflected and cooled. The particles repeatedly rebound off the labyrinth walls. This slows them down, they cool down, and ultimately, only non-glowing particles remain, which can no longer ignite a fire and whose velocity is so low or zero that they can no longer cause injury. As previously explained, the particles were either detached from the cutting or grinding wheel or were detached from the material being processed by the cutting or grinding wheel. The cooled particles either fall out of an outlet at the end of the labyrinth structure, or they can be extracted from the labyrinth structure by suction, for example.The labyrinth structure can be formed by an arrangement of multiple curved or angled channels, such that the entering particles undergo several changes of direction as they pass through the channel sections of the labyrinth structure. In particular, the labyrinth structure is designed and arranged such that the particles passing through it undergo three or more changes of direction, and especially five or more. At least one boundary wall of the labyrinth structure can be meandering or undulating.

[0008] In a further development of the invention, the labyrinth structure extends parallel to the circumferential wall on an outer surface of the circumferential wall. The outer surface faces the inner surface, with the inner surface defining an interior space in sections, in which the cutting or grinding disc is arranged. Such a design keeps the cover compact, making it particularly suitable for mobile cutting or grinding disc tools, such as one-handed or two-handed angle grinders.

[0009] In a further development of the invention, the labyrinth structure has at least two channel sections which are arranged at an angle of more than 45° to each other.

[0010] In this way, it can be ensured that the particles entering the labyrinth structure repeatedly hit the boundary walls of the labyrinth structure and bounce off the boundary walls again.

[0011] In a further development of the invention, the labyrinth structure has at least two channel sections that connect to each other and that each run in a circular base section shape, an elliptical section shape, an oval section shape, are freely curved or angled.

[0012] In this way, a compact labyrinth structure can be created that requires little installation space and with which the incoming particles can be effectively slowed down and cooled. In a further development of the invention, two to five, in particular three to four, channel sections are provided, which connect to one another and which each run in the shape of a circular arc segment, an elliptical segment segment, an oval segment segment, a free curve or an angle.

[0013] With two to five, especially three to four, channel sections, sufficient deceleration and cooling of the particles in the labyrinth structure can be ensured.

[0014] In a further development of the invention, the channel sections are each curved in the same direction.

[0015] This prevents the particles from passing through the labyrinth structure too quickly and without sufficient deceleration and cooling. In other words, it prevents the formation of a racetrack for the passing particles and ensures that the particles remain within the labyrinth structure long enough to guarantee adequate cooling. At the junction of successive channel sections, rounded channel walls can be incorporated, which can be achieved using transition sections, to avoid sharp edges protruding into the path of the particles or into the flow path defined by the channel sections.

[0016] In a further development of the invention, several openings are provided in the circumferential wall, in particular two to four openings, in particular three openings, wherein a labyrinth structure is connected to each of the openings.

[0017] In this way, a large proportion of the particles detached by or through the cutting or grinding disc can be introduced into the respective labyrinth structure. Furthermore, it can be ensured that, depending on where on the circumference of the cutting or grinding disc the disc contacts the workpiece, the particles detached by or through the cutting or grinding disc enter the labyrinth structure. For example, a worker using a one-handed or two-handed angle grinder does not always work with the angle grinder in the same orientation relative to the workpiece. Rather, depending on whether corners or flat areas are being worked, the angle grinder will be held differently, thus processing the workpiece with varying points on the circumference of the cutting or grinding disc.This means that the rotating cutting or grinding disc is accessible over a certain angular range, which is kept clear by the cover, and that within this angular range, the cutting or grinding disc comes into contact with the material being processed at different points. Depending on where the cutting or grinding disc comes into contact with the material, the particles detached by or through the cutting or grinding disc are also transported away from different points on the disc's circumference. Several openings in the cover, each followed by a labyrinth structure, ensure that a large proportion of the particles detached by or through the cutting or grinding disc are slowed down in the respective labyrinth structures connected to the openings.

[0018] In a further development of the invention, the labyrinth structure is provided with a connecting pipe for a suction device, in particular for a vacuum cleaner.

[0019] In a further development of the invention, a collection container is provided and an outlet of the labyrinth structure leads into the collection container.

[0020] In a further development of the invention, the cover is made of plastic or metal, in particular sheet metal or sheet steel.

[0021] The problem underlying the invention is also solved by a cutting or grinding wheel tool, in particular an angle grinder, which is provided with a cover according to the invention.

[0022] In a further development of the invention, the cover is adjustable relative to a base body of the cutting or grinding wheel tool relative to an axis of rotation of the cutting or grinding wheel, in particular rotatable.

[0023] In this way, the opening from which the labyrinth structure originates, or the openings from which a labyrinth structure originates, can be arranged so that a large proportion of the particles detached by or through the cutting or grinding wheel, in other words a large proportion of the sparks, enter the opening in the circumferential wall of the cover and thus the labyrinth structure.

[0024] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention. Individual features of the different embodiments illustrated and / or described can be combined with one another in any way without exceeding the scope of the invention. This also applies to the combination of individual features without other features with which they are illustrated and / or described. The drawings show:

[0025] Fig. 1 shows a schematic representation of a cutting or grinding disc tool according to the invention, specifically a battery-powered angle grinder,

[0026] Fig. 2 shows a sectional view of a cover of the cutting or grinding wheel tool of Fig. 1.

[0027] Fig. 3 shows a first side view of the cover of Fig. 2,

[0028] Fig. 4 shows a second side view of the cover of Fig. 2,

[0029] Fig. 5 shows a view of the cover of Fig. 2 from a rear oblique angle,

[0030] Fig. 6 shows a sectional view and two side views of another cover according to the invention,

[0031] Fig. 7 shows a view of the cover of Fig. 6 from a front oblique angle and

[0032] Fig. 8 shows a view of the cover of Fig. 6 from a rear oblique angle.

[0033] Fig. 1 shows a cutting or grinding disc tool according to a first embodiment of the invention in the form of a battery-powered angle grinder 10. The angle grinder 10 has a cutting or grinding disc 12, shown schematically only by its outline, which rotates about a pivot axis 40 of the angle grinder 10 in the direction of a curved arrow 14 and can be driven by a motor of the angle grinder 10 (not shown). The electrical energy for operating the motor is taken from a battery 16, which is replaceably attached to a housing 18 of the angle grinder 10. The housing of the angle grinder 10 is gripped with one hand, and a second hand grips a handle 20 of the angle grinder 10.

[0034] The angle grinder 10 is provided with a cover 22 for the cutting or grinding disc 12, which has a circumferential wall 24 extending section by section along a portion of the circumference of the cutting or grinding disc 12. The circumferential wall 24 runs parallel to and at a distance of, for example, approximately 5 mm from the outer circumference of the cutting or grinding disc 12 when the cutting or grinding disc 12 is new and unused. During use, the cutting or grinding disc 12 wears down, thereby reducing its outer circumference, so that the distance to the circumferential wall 24 of the cover 22 increases. In the illustrated embodiment, the circumferential wall 24 of the cover 22 extends over an angle of approximately 180° along the circumference of the cutting or grinding disc 12.The cover 22 can be rotatably attached to the housing 18 of the angle grinder 10 to allow a flexible working posture when working with the angle grinder 10.

[0035] The cutting or grinding wheel 12 is used to process a workpiece 26 that is only shown schematically.

[0036] The circumferential wall 24 has an opening 28, to which a labyrinth structure 30 is connected in Fig. 1. The labyrinth structure 30 is formed by means of a multiply curved channel, whereby in the view of Fig. 1 the inner boundary wall of the labyrinth structure 30 is shown with a dashed line, since it is concealed in the representation of Fig. 1 by a cover plate of the labyrinth structure 30. To clarify the course and arrangement of this multiply curved channel of the labyrinth structure 30, a wavy arrow 32 is drawn, which extends from the opening 28 in the circumferential wall 24 along the curved channel of the labyrinth structure 30 to an outlet 34 of the labyrinth structure 30. The wavy arrow 32 serves only to clarify the channel that leads through the labyrinth structure 30, but in no way represents a trajectory of particles through the labyrinth structure 30.

[0037] The labyrinth structure 30 provides a braking and cooling section for particles detached from or by means of the cutting or grinding wheel 12. Such particles can be detached from the cutting or grinding wheel 12 itself or from the workpiece 26 being machined. Both the particles detached from the cutting or grinding wheel 12 and those detached from the workpiece 26 are generally very hot and glowing, resulting in a shower of sparks or sparks emanating from the point of contact between the cutting or grinding wheel 12 and the workpiece 26, as is known. The particles or sparks move tangentially away from the point of contact between the cutting or grinding wheel 12 and the workpiece 26, forming a shower of sparks that expands in a triangular shape from the point of contact.The majority of the particles forming this shower of sparks will consequently strike a section of the circumferential wall 24 that lies upstream of the opening 28 in the direction of rotation, corresponding to arrow 14, of the cutting or grinding wheel 12. As soon as the particles enter the area of ​​the opening 28, they will at least partially enter the labyrinth structure 30 and thus the curved channel formed by the labyrinth structure 30. The mostly still glowing particles then repeatedly strike the boundary walls of the curved channel formed by the labyrinth structure 30 and are thereby slowed down and cooled. In order to traverse the entire curved channel, the particles must, as can be seen in Fig. 1, first be deflected by 180° and then pass through four curved sections of the labyrinth structure 30. This is shown in Fig.1. It can be seen that the particles, as they travel through the labyrinth structure 30, repeatedly collide with and rebound against the boundary walls of the labyrinth structure 30, thereby being effectively slowed down and cooled. Once the particles have passed through the curved channel of the labyrinth structure 30, they can exit through the outlet 34 of the labyrinth structure 30. The rotating cutting or grinding wheel 12 also generates an airflow that flows through the multiply curved channel of the labyrinth structure 30 and also transports particles that have already been completely slowed down to the outlet 34.

[0038] Within the scope of the invention, a collection container can be provided at the outlet 34 or downstream of the outlet 34, or a suction device can, for example, be connected to the outlet 34.

[0039] Regarding Fig. 1, it should be noted that the wavy arrow 32 is shown merely to illustrate the curved channel formed by the labyrinth structure 30. The wavy arrow 32 does not, however, indicate the path of the particles through the labyrinth structure 30. Rather, the particles entering the labyrinth structure 30 will bounce off its boundary walls multiple times, thereby being effectively slowed down and cooled. In other words, the labyrinth structure 30 does not form a racetrack or a collision-free path; instead, it is designed such that the particles bounce off its boundary walls multiple times.

[0040] Fig. 2 shows a sectional view of the cover 22 of Fig. 1, wherein the section plane is perpendicular to an axis of rotation 40 of the cutting or grinding wheel 12, the axis of rotation 40 being marked again in Fig. 2 for clarity only.

[0041] Figure 2 shows the circumferential wall 24 of the cover with the opening 28. The multiply curved channel of the labyrinth structure 30 adjoins the opening 28. It can be seen that downstream of the opening 28, the channel initially has a circular arc section extending over an angle of slightly more than 180° and having a constant rectangular cross-section. According to the invention, both the angle of the deflection and the cross-section of the channel can be changed. After this first section 42, the channel has a second section 44, which has the same curvature as the first section 42, but extends over an angle of only about 45°. A third section 46 and a fourth section 48 adjoin the second section, the third section 46 and the fourth section 48 each extending over an angle of about 45° and having a constant rectangular cross-section.

[0042] Between sections 42, 44, 46, and 48, respectively, transition sections 43, 45, and 47 are arranged in which the curvature of the channel runs in the opposite direction to the curvature in sections 42, 44, 46, and 48, and in which the cross-section of the channel is larger than in sections 42, 44, 46, and 48. These transition sections 43, 44, 46, and 47 ensure that the particles collide with the boundary walls of the labyrinth structure 30 and are thereby effectively slowed down. The transition sections 43, 44, 46, and 47 are rounded so that sharp edges or corners protruding into the flow path of the particles between the channel sections are avoided. A radially inner boundary wall of the labyrinth structure in the area of ​​channel sections 42, 44, 46, 48 is meandering or wavy.The fourth section 48 is followed by a final section 49, which has a curvature opposite to that of the fourth section 48 and which then leads into the outlet 34 of the labyrinth structure 30.

[0043] The labyrinth structure 30 thus forms a multiply curved channel whose curvature changes sign. In the illustrated embodiment, the cross-section of the channel is not constant. In the illustrated embodiment, the magnitude of the curvature along the channel is also not constant.

[0044] Fig. 3 shows a side view of the cover 22, with the boundary walls of the multiply curved channel of the labyrinth structure 30, which are hidden in Fig. 3, shown as dashed lines.

[0045] Fig. 4 shows another side view of the cover 22 of Fig. 2, where again the boundary walls of the labyrinth structure hidden in Fig. 4 are shown as dashed lines.

[0046] Fig. 5 shows a view of the cover 22 from a rear oblique angle, with the boundary walls of the labyrinth structure 30, which are hidden in Fig. 5, again shown as dashed lines.

[0047] Fig. 6 shows a sectional view and two side views of a cover 44 according to the invention for a cutting or grinding wheel according to a further embodiment. The section plane AA is shown in the upper side view of Fig. 6. It can be seen from the sectional view that the cover 44 has a labyrinth structure composed of three sub-labyrinth structures 30A, 30B and 30C. The sub-labyrinth structures 30A, 30B, 30C follow one another in the direction of rotation of a cutting or grinding wheel, as indicated by the curved arrow 14. Each of the partial labyrinth structures 30A, 30B, 30C is constructed similarly to the labyrinth structure 30 of Fig. 2, except that only three curved sections of the multiply curved channel are provided, each connected to the other by means of a transition section, and an end section is immediately connected upstream of the respective outlet 34A, 34B, 34C. From a [context missing] in Fig.6 particles not shown, which are detached or detached by means of the cutting or grinding wheel, enter partly the partial labyrinth structure 30A, partly the partial labyrinth structure 30B and partly the partial labyrinth structure 30C and leave the respective partial labyrinth structure 30A, 30B or 30C again at the respective outlet 34A, 34B, 34C.

[0048] The partial labyrinth structures 30A, 30B, 30C each form sections of the circumferential wall in the cover 44, and the successive partial labyrinth structures 30A, 30B, 30C extend over an angle of 180° along the circumference of the grinding wheel.

[0049] The cover 44 can slow down and cool a large proportion of the particles detached by or through the cutting or grinding wheel, so that no disturbing and potentially dangerous sparks are produced.

[0050] Fig. 7 shows the cover 44 in a front oblique view. In this view, an opening 28A can be seen, to which the partial labyrinth structure 30A is connected.

[0051] Fig. 8 shows another view of the cover 44 from a rear oblique angle, in which the outlets 34A, 34B and 34C of the partial labyrinth structures 30A, 30B and 30C can be seen.

Claims

Patent claims 1. Cover for a cutting or grinding disc with a circumferential wall which extends at least sectionally parallel to a circumference of the cutting or grinding disc and at least along a part of a circumference of the cutting or grinding disc, wherein at least one opening for the inlet of particles that have been detached from or by means of the cutting or grinding disc is provided in the circumferential wall, characterized in that a labyrinth structure adjoins the opening, so that particles passing through the opening repeatedly strike boundary walls of the labyrinth structure and rebound.

2. Cover according to claim 1, characterized in that the labyrinth structure extends parallel to the circumferential wall on an outer surface of the circumferential wall.

3. Cover according to claim 1 or 2, characterized in that the labyrinth structure has at least two channel sections which are arranged at an angle of more than 45 degrees to each other.

4. Cover according to one of the preceding claims, characterized in that the labyrinth structure has at least two channel sections which connect to each other and which each run in a circular arc segment shape, an elliptical segment shape, an oval segment shape, are freely curved or angled.

5. Cover according to claim 4, characterized in that two to five, in particular three to four, channel sections are provided which connect to one another and which each run in a circular arc segment shape, an elliptical segment shape, an oval segment shape, are freely curved or angled.

6. Cover according to claim 4 or 5, characterized in that the channel sections are each curved in the same direction.

7. Cover according to at least one of the preceding claims, characterized in that several openings are provided in the circumferential wall, in particular two to four openings, in particular three openings, wherein a labyrinth structure is connected to each of the openings.

8. Cover according to at least one of the preceding claims, characterized in that the labyrinth structure is provided with a connecting pipe for a suction device, in particular for a vacuum cleaner.

9. Cover according to at least one of the preceding claims, characterized in that a collection container is provided and that an outlet of the labyrinth structure opens into the collection container.

10. Cover according to at least one of the preceding claims, characterized in that the cover is made of plastic or metal, in particular sheet metal or sheet steel.

11. Cutting or grinding disc tool, in particular angle grinder, characterized by a cover according to one of the preceding claims.

12. Cutting or grinding wheel tool according to claim 11, characterized in that the cover is adjustable relative to a base body of the cutting or grinding wheel tool relative to an axis of rotation of the cutting or grinding wheel, in particular rotatable.

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