Blocking element for an emergency brake unit of a saw device, and saw device

Abstract

The invention relates to a blocking element (26) for an emergency brake unit (24) of a saw device (10) with a circular disc-shaped sawblade (12). The blocking element (26) comprises a bearing section (38) via which the blocking element (26) can be supported on the saw device (10), a head section (42) which is designed to selectively engage into the sawblade (12) in order to brake same, and a deformation section (64). The deformation section (64) lies between the bearing section (38) and the head section (42) and / or connects the bearing section (38) and the head section (42) together. The deformation section (64) is arc-shaped and is designed to plastically shorten along an arc circumferential direction (66) in order to brake the sawblade (12). Furthermore, a saw device (10) is provided with a circular disc-shaped sawblade (12) and an emergency brake unit (24). The emergency brake unit (24) comprises such a blocking element (26), and the blocking element (26) is mounted on the saw device (10) such that the blocking device can selectively engage into the sawblade (12) in order to brake the sawblade (12).

Description

[0001] Blocking element for an emergency brake unit of a sawing device and sawing device

[0002] The invention relates to a blocking element for an emergency brake unit of a sawing device with a circular disk-shaped saw blade.

[0003] Furthermore, the invention relates to a sawing device with a circular disk-shaped saw blade and an emergency brake unit, wherein the emergency brake unit comprises such a blocking element.

[0004] Sawing devices with emergency braking units are known from the state of the art.

[0005] The emergency brake unit, and in particular the locking element it comprises, serves to stop the rotation of the saw blade in the event of an imminent or existing risk of injury. This prevents injuries to users of the sawing device or at least reduces their severity. In other words, safe operation of the sawing device is ensured.

[0006] In this context, it is important to stop the saw blade's rotation within a relatively short time. However, this means that the kinetic energy of the saw blade must be absorbed by the components of the emergency brake unit and / or the other components of the sawing device within this short time. Therefore, comparatively high forces act on the components of the emergency brake unit and / or the other components of the sawing device.

[0007] This may result in one or more components of the emergency brake unit and one or more components of the sawing device being deformed or otherwise damaged after use, so that they must be replaced before the sawing device can be used again.

[0008] It is therefore the object of the present invention to provide an emergency braking unit by means of which a rotation of a saw blade can be stopped within a comparatively short time, while at the same time as few components of the emergency braking unit and / or an associated sawing device as possible are impaired in their functionality.

[0009] The problem is solved by a blocking element for an emergency braking unit of a sawing device with a circular disk-shaped saw blade. The blocking element comprises a bearing section, via which the blocking element can be mounted on the sawing device, in particular rotatably. Furthermore, the blocking element comprises a head section designed to selectively engage with the saw blade for braking. In addition, the blocking element comprises a deformation section located between the bearing section and the head section and / or connecting the bearing section and the head section to one another. The deformation section is arc-shaped and designed to be plastically shortened along a circumferential direction of the arc for braking the saw blade. The kinetic energy of the rotation of the saw blade can thus be reliably and purposefully converted into a plastic shortening of the deformation section.This is achieved in particular by the arcuate shape of the deformation section and its position between the bearing section and the head section. Consequently, rotation of the saw blade can be stopped in a comparatively short time. Since the deformation section is specifically designed to be plastically shortened along the circumferential direction of the arc, it can absorb a comparatively large amount of kinetic energy with respect to the installation space occupied by the deformation section and convert it into plastic shortening. This also means that forces resulting from the braking of the saw blade are reliably and precisely absorbed by the deformation section. As a result, only comparatively low forces act on the other components of the emergency braking unit. The same applies to components of the associated sawing device.Therefore, the functionality of the remaining components of the emergency brake unit and the sawing device components is not affected by an emergency braking process initiated by the blocking element. This applies in particular to the saw blade, which can thus be reused when the sawing device is restarted.

[0010] With regard to the arcuate shape of the deformation section, it should be noted that deformation sections that are arcuate in sections are also considered arcuate. Therefore, a deformation section composed of an arcuate segment and a straight segment is also an arcuate deformation section.

[0011] An arc shape includes, for example, a circular arc shape or an elliptical arc shape. The part of a circle line belonging to a circular area sector is called a circular arc. Similarly, the part of an elliptical line belonging to an elliptical area sector is called an elliptical arc.

[0012] Preferably, the bearing portion and the head portion of the blocking element are provided at opposite ends of the blocking element.

[0013] The bearing section can have a receptacle for a bearing element, e.g., a bearing pin. Preferably, a central axis of such a receptacle runs parallel to a central axis associated with the arcuate circumferential direction of the deformation section. Thus, the blocking element is rotatably mounted on the bearing pin via the bearing section.

[0014] Furthermore, an interface for coupling the blocking element to an actuator can be provided on the head section. The blocking element, or more precisely the associated head section, can thus be quickly and reliably brought into engagement with the saw blade.

[0015] In addition, an interface for locking the blocking element in a normal position, which will be explained later, can be provided on the head section. Such a locking mechanism prevents the head section from undesired engagement with the saw blade. The interface for coupling the blocking element to an actuator and the interface for locking the blocking element in the normal position can be combined or integrally formed.

[0016] In this context, a sawing device with a circular disk-shaped saw blade can also be referred to as a circular sawing device or simply a circular saw. Examples of such sawing devices include miter saws, table saws, hand-held circular saws, and plunge-cut saws.

[0017] Locking elements for emergency brake units of sawing devices are also colloquially referred to as brake wedges. This applies regardless of whether the locking element is wedge-shaped or acts as a wedge.

[0018] When the blocking element is mounted in a sawing device, the arcuate deformation section can be arranged, in particular, concentrically with the circular disk-shaped saw blade. This allows the blocking element to engage the saw blade quickly and reliably. Furthermore, the kinetic energy of the saw blade's rotation can be easily and reliably transferred to the blocking element and, in particular, the deformation section. Furthermore, such an arrangement of the deformation section saves space.

[0019] Preferably, the blocking element is designed and / or manufactured in one piece. For example, the blocking element can be designed as a cast or injection-molded part.

[0020] One-piece blocking elements can be easily recycled after use, i.e., when the deformed section has been plastically shortened. For example, used blocking elements can be melted down and processed into new blocking elements.

[0021] The blocking element can be made of plastic or metal, e.g., an aluminum alloy. In one embodiment, the deformation section extends over a portion of the arc's circumferential direction with a center angle of 15 degrees to 90 degrees. Depending on the application, a suitable circumferential length of the deformation section can thus be set. In other words, a suitable length of a braking distance for the saw blade can be set. This ensures that the saw blade comes to a stop reliably and within a specified time period.

[0022] Example deformation sections extend over a section of the arc's circumferential direction with a central angle of approximately 40 degrees, approximately 45 degrees, approximately 50 degrees, approximately 55 degrees, or approximately 60 degrees. In another example, the deformation section extends over a section of the arc's circumferential direction with a central angle of approximately 65 degrees, approximately 70 degrees, or approximately 75 degrees.

[0023] The head section can be shorter than the deformation section along the arc's circumferential direction. This provides a comparatively large installation space for the deformation section. As a result, the energy to be absorbed by the deformation section can be absorbed over a comparatively long period of time. This reduces the mechanical stress on the other components of the sawing device.

[0024] In this context, exemplary head sections extend over a section of the arc circumferential direction with a central angle of approximately 20 degrees, approximately 25 degrees, approximately 30 degrees, approximately 35 degrees or approximately 40 degrees.

[0025] In one example, the head section extends over a section of the arc's circumferential direction with a central angle of approximately 30 degrees, and the deformation section, together with the bearing section, extends over a section of the arc's circumferential direction with a central angle of approximately 60 degrees. The deformation section and the bearing section are therefore together twice as long as the head section. In this example, the blocking element extends over a section of the arc's circumferential direction with a central angle of approximately 90°. According to one variant, the head section projects radially inward relative to the deformation section in the arc's circumferential direction. When the blocking element is in the assembled state, the deformation section is at a greater distance from an outer circumference of the saw blade than the head section. Due to the comparatively shorter distance, the head section can engage with the saw blade quickly and reliably.The distance of the deformation section from the outer circumference of the saw blade can also be selected such that even in a plastically deformed state of the deformation section, it is still spaced from the saw blade. In this way, the plastic shortening of the deformation section is not hindered by any contact between the deformation section and the outer circumference of the saw blade, in particular the teeth. The distance of the deformation section from the outer circumference of the saw blade and / or a drive shaft of the saw blade can be designed to vary for different blocking elements intended for use in different sawing devices. Thus, the blocking element can be adapted to different sawing devices with different saw blades.

[0026] In the area of ​​the head section that protrudes radially inward relative to the deformation section, an engagement section or saw-in section for the saw blade can be provided. This section is specifically designed to reliably couple the saw blade to the head section. For this purpose, the engagement section or saw-in section can comprise a material that is particularly easy to saw into. This results in a smooth coupling between the saw blade and the head section, i.e., a smooth transition from an uncoupled to a coupled state of the saw blade and the head section.

[0027] Furthermore, it can be provided that the head section comprises regions of different stiffness and / or ductility. This can be achieved by an appropriate arrangement of cavities and / or materials. The cavities can be designed as holes or bores. Alternatively, different stiffnesses can be achieved by an appropriate shape of the head section. In both variants, an area of ​​the head section that is sawn into first when the head section engages the saw blade can be provided with comparatively low stiffness and / or ductility. Subsequently sawn areas can be provided with greater stiffness and / or greater ductility. In this way, a coupling of the saw blade to the head section is established in a gentle manner. At the same time, the coupling, once established, is comparatively strong, so that high forces can be transmitted.

[0028] In one embodiment, the head section comprises regions of different materials. As already explained, different materials can be used to create regions of different stiffness and / or different ductility within the head section. In this context, for example, a comparatively soft material, e.g., plastic, can be used in the region of an end of the head section facing the saw blade and / or in a region lying within a saw blade plane. Consequently, a comparatively small cutting force is required to saw into this region, resulting in a smooth sawing operation. Other regions can comprise a metal material.

[0029] In one example, the head section has a guide surface for acting on the head section in the direction of the saw blade. The guide surface has a normal with an extension component pointing radially outwards. The radial direction is defined with reference to the circumferential direction of the arc. The acting comprises, in particular, the application of force. The head section can therefore be acted upon with force in the direction of the saw blade, resulting in a reliable coupling between the saw blade and the head section for braking the saw blade. The guide surface can be flat. Alternatively, the guide surface comprises a section of a circular cylinder surface. The guide surface is therefore curved. In both cases, the guide surface can be designed such that when the head section is coupled to the saw blade, self-reinforcing occurs, i.e. the guide surface further acts on the head section in the direction of the saw blade.

[0030] The head section can have greater rigidity along the arc's circumferential direction than the deformation section. Thus, when the blocking element is used, the deformation section is specifically deformed. The kinetic energy of the saw blade's rotation is thus specifically absorbed by the deformation section. The head section deforms less in comparison. In particular, the rigidities of the head section and the deformation section can be adjusted such that the head section essentially does not deform. In one example, the rigidity of the head section is twice as great as the rigidity of the deformation section.

[0031] It is understood that the deformation section is designed to absorb essentially the entire kinetic energy of the saw blade's rotation. However, a portion of the kinetic energy is also absorbed by the sawing of the head section and by the deformation of the head section. However, the portion of the kinetic energy absorbed by the head section is comparatively small or even negligible compared to the portion absorbed by the deformation section.

[0032] According to one variant, the deformation section comprises a structure that is plastically deformable in the circumferential direction of the arc and has predetermined deformation points. Plastic shortening of the deformation section is thus achieved by plastically deforming the deformable structure. In particular, the deformation takes place in the region of the predetermined deformation points. This results in a well-defined deformation of the deformation section. In other words, this prevents the deformation section from being displaced into undesirable areas during its plastic shortening, e.g., from undesirably bulging or buckling.

[0033] In particular, the plastically deformable structure comprises structural elements that are designed to fold, turn over, or collapse when a force is applied. Such structural elements can run along the force flow and / or obliquely and / or transversely to the force flow. It is also possible for the plastically deformable structure to comprise a plastically compressible material. An example of a plastically compressible material is a porous material such as a foam material. The deformation section can have a plurality of cavities. The cavities are arranged adjacently along the circumferential direction of the arc. The cavities are to be understood as macroscopic cavities. The cavities thus form a row along the circumferential direction of the arc. It is of course also possible to provide two or more rows of cavities.Furthermore, the cavities serve to be folded or folded along the arc's circumferential direction, thus converting the kinetic energy resulting from the rotation of the saw blade into plastic deformation of the deformation section. The number, arrangement, shape, and size of the cavities allow the deformation behavior of the deformation section to be specifically adjusted.

[0034] In one design alternative, the cavities are continuous in a direction that runs axially relative to the circumferential direction of the arch. The cavities are thus open on both axial sides and thus represent through-openings. Such cavities are particularly easy to manufacture. Furthermore, such cavities are particularly easy to fold or collapse for energy absorption.

[0035] On the one hand, the cavities can be manufactured subtractively. In this context, the cavities are created by removing material from an at least partially solid deformation section. The cavities can be created by cutting, punching, milling, drilling, or other suitable manufacturing processes. On the other hand, the cavities can be incorporated into the deformation section during its manufacture. If the deformation section is manufactured using a casting or injection molding process, the cavities can be provided using this casting or injection molding process.

[0036] In this context, a group of cavities can also be referred to as a cavity pattern or pattern of cavities.

[0037] In one variant, at least one cavity is defined by a wall of constant wall thickness. Such cavities can be folded or collapsed particularly reliably. This depends on the direction of the force applied, the shape of the cavity, and the wall thickness. The wall thickness can be used, in particular, to adjust the force required to fold or collapse the cavity. The wall thickness can therefore be varied to adapt the blocking element to different sawing devices. Furthermore, constant wall thicknesses are particularly advantageous for producing the deformation section using a casting or injection molding process.

[0038] The fact that a cavity or several cavities each have a constant wall thickness does not preclude the provision of cavities with different wall thicknesses within the deformation section. In particular, wall thicknesses can be varied in this context to adjust the stiffness of the deformation section. A stiffness gradient can also be created within the deformation section.

[0039] The cavities can be formed by adjacently arranged ring segments. Such ring segments can be folded or folded in a defined manner along the arc's circumferential direction and can therefore convert kinetic energy into plastic deformation in a defined manner. The ring segments can be spaced apart from one another, directly adjacent to one another, or nested within one another.

[0040] In one example, a deformation section provided with a single row of cavities comprises 5 to 20 ring segments. A first preferred embodiment comprises seven ring segments. A second preferred embodiment comprises eleven ring segments.

[0041] In one embodiment, at least one of the cavities has a circular, crescent-shaped, or polygonal cross-section. In this context, a crescent shape is understood to be the difference in area between two overlapping circular areas. The cross-sectional shape of the cavities defines a ratio of the length of the deformation section in a non-deformed state to that in a plastically deformed state. Thus, by selecting the cross-sectional shape, the extent to which the deformation section plastically shortens when a corresponding force is applied can be adjusted.

[0042] In this context, the cavities of ring segments with a circular or circular-segment-shaped cross-section are delimited by a wall that, at least in sections, has the shape of a circular cylinder shell. In cavities with a polygonal cross-section, the corresponding wall has the shape of a cylinder shell with a polygonal base. In such ring segments, it is particularly advantageous if at least one corner of the cross-section points radially inward or radially outward with respect to the circumferential direction of the deformation section. Such ring segments can be folded with particular precision along the circumferential direction of the arc.

[0043] In a case in which the deformation section comprises a series of ring segments and at the same time the deformation section is to have a distance greater than zero from the outer circumference of the saw blade in a plastically shortened state, i.e. in an end position of the blocking element, a radial extension of the deformation section with respect to the circumferential direction of the arc can be calculated as the sum of half the inner circumference of the cavity and twice the wall thickness of the associated ring segment. This is based on the idea that the ring segment is compressed in the circumferential direction such that the cavity is completely closed. In order to ensure a distance from the outer circumference of the saw blade, the radial extension of the deformation section in its deformed state must be smaller than a radial distance between the outer circumference of the saw blade and the guide element.

[0044] A filler material can be arranged inside at least one cavity. The filler material can also be referred to as an inlay. Preferably, the filler material is different from the material from which the deformation section itself is made. The filler material can be elastically and / or plastically deformable. Consequently, the filler material can be used to further adjust the stiffness of the deformation section and thus its deformation behavior. A filler material can be arranged in an individual cavity, in a group of cavities, or in all cavities.

[0045] Furthermore, the deformation section can have a stiffness curve. The stiffness of the deformation section is therefore not constant along the circumferential direction of the arc. This can be achieved by having adjacent sections, e.g. adjacent ring segments, of a plastically deformable structure of the deformation section have different stiffnesses. In a first example, the deformation section has a lower stiffness at an end facing the head section than at an end facing the bearing section. In a second example, the opposite is true, i.e., the deformation section has a greater stiffness at an end facing the head section than at an end facing the bearing section. In both cases, a stiffness curve serves to gently and smoothly introduce the kinetic energy resulting from the rotation of the saw blade and the associated forces into the deformation section.This gently brakes the saw blade. At the same time, a strong braking effect is ensured by a stiffness curve with a large gradient.

[0046] The object is further achieved by a sawing device with a circular disk-shaped saw blade and an emergency braking unit. The emergency braking unit comprises a blocking element according to the present invention. The blocking element is mounted on the sawing device in such a way that it can selectively engage with the saw blade to brake the saw blade. The kinetic energy of the rotation of the saw blade can thus be selectively converted reliably and specifically into a plastic shortening of the deformation section. This allows rotation of the saw blade to be stopped in a comparatively short time. The forces resulting from the braking of the saw blade are reliably and specifically absorbed by the deformation section of the blocking element. Consequently, only comparatively low forces act on the other components of the emergency braking unit. The same applies to components of the associated sawing device.This ensures that the functionality of the remaining components of the emergency braking unit and the sawing device components is not affected by an emergency braking process initiated by the blocking element. This applies in particular to the saw blade, which can be reused when the sawing device is restarted.

[0047] When installed, the emergency braking unit is coupled to a sensor unit for detecting actual or imminent contact by a user and is operated based on the sensor unit's detection result. This allows the emergency braking unit to be triggered in a timely and targeted manner, preventing injury to the user entirely or at least limiting its severity.

[0048] The emergency brake unit further comprises an actuator that can be triggered selectively, particularly depending on the detection result. The actuator is coupled to the blocking element, more precisely to the associated head section, so that it can be quickly and reliably brought into engagement with the saw blade. The actuator comprises, for example, a lifting magnet or a shape memory alloy actuator.

[0049] In a normal position, the blocking element can be arranged parallel to a circumference of the saw blade. This means that the sections forming the blocking element each have a constant radial distance from the saw blade along an outer circumference of the saw blade. In particular, the head section and the bearing section of the blocking element have essentially the same radial distance from the central axis of the saw blade and from the outer circumference of the saw blade along the outer circumference of the saw blade. Furthermore, in this context, a central axis of the arcuate deformation section and an axis of rotation of the saw blade preferably coincide substantially. The normal position is defined by the fact that the blocking element is in an operational position but has not yet been brought into engagement with the saw blade, i.e. the emergency brake unit has not yet been triggered.Overall, the blocking element is positioned within the sawing device in a space-saving manner, while also being arranged so that the head section of the blocking element only has to overcome a relatively small distance to engage the saw blade. This allows the saw blade to be brought to a standstill relatively quickly. In the normal position, the radial distance of the deformation section from the saw blade can be greater than the radial distance of the head section from the saw blade. As already explained, this prevents undesirable interactions between the deformation section and the saw blade.

[0050] In an end position of the blocking element, the deformation section can be radially spaced from the saw blade. An end position of the blocking element is understood to be the position the blocking element assumes after it has engaged the saw blade and slowed its rotation to a standstill. The end position therefore refers to a position after emergency braking has taken place. The deformation section does not come into contact with the saw blade. This allows the deformation section to undergo plastic deformation without being influenced by the saw blade. Furthermore, the deformation section is not sawn into or into the saw blade. It therefore remains structurally intact, allowing it to effectively convert kinetic energy into plastic deformation.

[0051] In addition, the blocking element can optionally be dismantled separately from an actuator unit of the emergency brake unit and / or separately from a control unit of the emergency brake unit from the sawing device. Dismantled separately from the actuator unit and / or separately from a control unit means that the blocking element can be dismantled from the sawing device without the actuator unit and / or the control unit of the emergency brake unit having to be dismantled at the same time. This does not include, of course, assembly elements, bearing elements, holding elements and fastening elements by means of which the blocking element is mounted. In other words, the blocking element can be dismantled individually with respect to the actuator unit and / or the control unit. Thus, the blocking element can be replaced on its own or individually. The actuator unit and / or the control unit of the emergency brake unit remain or must be.remains mounted on the sawing device during such a replacement. This means that the blocking element can be removed quickly and easily. This applies in principle to all operating states of the sawing device and the emergency brake unit, but in particular to a state after the emergency brake unit has been triggered, i.e. when the blocking element engages or has engaged the saw blade. This means that the emergency brake unit and the sawing device can be put back into operation quickly and easily after the emergency brake unit has been triggered. A machining task can therefore be continued and completed promptly. The fact that the blocking element can be replaced individually also means that triggering the emergency brake unit and making the triggered emergency brake unit ready for use incurs comparatively little cost.

[0052] In a preferred embodiment, the blocking element can be removed separately from all other components of the emergency brake unit. In other words, the blocking element can be removed individually with respect to all other components of the emergency brake unit. The described effects and advantages are thereby achieved to a particularly high degree.

[0053] In a further preferred embodiment, the blocking element, the actuator unit, and the control unit of the emergency brake unit can each be removed separately from all other components of the emergency brake unit. In other words, the blocking element can be removed individually with respect to all other components of the emergency brake unit. In addition, the actuator unit can be removed individually with respect to all other components of the emergency brake unit. Furthermore, the control unit of the emergency brake unit can be removed individually with respect to all other components of the emergency brake unit. Thus, individual components of the emergency brake unit can be easily replaced, repaired, and / or maintained.

[0054] In a first alternative, the control unit of the emergency brake unit can be designed integrally with a motor control unit, which serves to control a drive motor designed to drive the saw blade. In a second alternative, the motor control unit and the control unit of the emergency brake unit are designed separately. However, they can be connected to each other via signaling, so that the drive motor can be deactivated easily and reliably when the emergency brake unit is triggered.

[0055] The invention will be explained below with reference to various embodiments shown in the accompanying drawings. Figure 1 shows a perspective view of a sawing device according to the invention, wherein the sawing device according to the invention comprises an emergency brake unit equipped with a blocking element according to the invention.

[0056] Figure 2 shows the sawing device from Figure 1 in a side view, with a guide element of the emergency brake unit omitted,

[0057] Figure 3 Parts of the sawing device from Figures 1 and 2 in a separate view,

[0058] Figure 4 shows a detailed view of the blocking element,

[0059] Figures 5 to 8 show parts of the sawing device from Figures 1 and 2 at different times after the emergency brake unit has been triggered,

[0060] Figure 9 shows a curve of a force absorbed by the blocking element over time after the emergency brake unit has been triggered,

[0061] Figure 10 Parts of the sawing device from Figures 1 and 2 when mounting the blocking element,

[0062] Figures 11 to 14 alternative designs for holding the blocking element in a normal position,

[0063] Figure 15 parts of a sawing device according to an alternative embodiment,

[0064] Figure 16 parts of a sawing device according to yet another alternative embodiment,

[0065] Figure 17 parts of a sawing device according to a further alternative embodiment, and

[0066] Figure 18 shows an additional embodiment of a sawing device according to the invention. Figures 1 and 2 show a sawing device 10 with a circular disk-shaped saw blade 12. In the example shown, the sawing device 10 is a cross-cut saw.

[0067] The sawing device 10 comprises a base assembly 14 and an arm assembly 16 rotatably mounted thereon.

[0068] The base assembly 14 has a support surface 18 on which a component to be machined, i.e. sawn off or sawn in, can be positioned.

[0069] Furthermore, the saw blade 12 can be set in rotation about a central axis A by actuating a drive motor M coupled thereto and can be brought into interaction with the component to be machined by displacing the arm assembly 16 relative to the base assembly 14.

[0070] In the example shown, the arm assembly 16 is moved relative to the base assembly 14 manually.

[0071] The arm assembly 16, or more generally the sawing device 10, comprises a frame 20 on which a drive shaft 22 is rotatably mounted. The drive shaft 22 is coupled to the drive motor M. The saw blade 12 is fixed to the drive shaft 22, so that the saw blade 12 can be driven in rotation in a known manner.

[0072] The sawing device 10 is further equipped with an emergency brake unit 24, which can be seen in detail in Figures 3 and 4.

[0073] For better visibility of the emergency brake unit 24, a housing part is not shown in Figures 1 and 2 in an area G. Such a housing part serves, on the one hand, to drain workpiece particles, e.g., sawdust or dust, generated by the use of the sawing device 10. On the other hand, such a housing part forms a portion of the handle provided at the end of the arm assembly 16 in the illustrated embodiment. Furthermore, the housing part serves to cover the saw blade 12.

[0074] The emergency brake unit 24 comprises a blocking element 26 which is rotatably mounted on the sawing device 10 via a bearing element 28 fixed to the frame 20 in the form of a fixed bearing pin 30 such that it can selectively engage with the saw blade 12 to brake the saw blade 12.

[0075] In addition, the emergency brake unit 24 comprises an actuator unit 32 which is designed to selectively bring the blocking element 26 into engagement with the saw blade 12.

[0076] In the example shown, the actuator unit 32 comprises an electrically controllable lifting magnet, which is not shown in detail in the figures.

[0077] The emergency braking unit 24 also includes an associated control unit 34.

[0078] In the illustrated embodiment, the control unit 34 is designed and arranged separately from the actuator unit 32 (see, for example, Figures 3 to 8). The actuator unit 32 and the control unit 34 are signal-coupled via a signal line.

[0079] This configuration allows the actuator unit 32 and the control unit 34 to be disassembled separately. This facilitates replacement, repair, or maintenance.

[0080] The control unit 34 is coupled to a sensor unit known per se for detecting an actual or impending contact of the saw blade 12 by a user.

[0081] Thus, the actuator unit 32 can be operated depending on a detection result of the sensor unit.

[0082] The emergency brake unit 24 further comprises a guide element 36 which is mounted on the frame 20 and guides a movement of the blocking element 26 along a guide direction F, as will be explained in more detail below.

[0083] The blocking element 26 is in a normal position in Figures 3 and 4. In this position, the blocking element is arranged parallel to a circumferential direction U of the saw blade 12.

[0084] The blocking element 26 is constructed from three sections.

[0085] The blocking element 26 comprises a bearing section 38. In the illustrated embodiment, the bearing section 38 is sleeve-shaped, ie the bearing section 38 comprises a circular-cylindrical bearing opening 40 which is delimited by a wall 41 with a substantially constant wall thickness.

[0086] The fixed bearing pin 30 is received in the bearing opening 40, so that the blocking element 26 is rotatably mounted on the frame 20 of the sawing device 10 via the bearing section 38 and the bearing pin 30.

[0087] The blocking element 26 further comprises a head portion 42.

[0088] The head portion 42 is provided at an end of the blocking element 26 opposite the bearing portion 38.

[0089] The head section 42 is designed to engage the saw blade 12 when the emergency brake unit 24 is actuated, i.e. driven by the actuator unit 32, in order to ideally brake it to a standstill.

[0090] In this context, the head section 42 comprises a coupling section 44.

[0091] The coupling section 44 is positioned at an end of the blocking element 26 opposite the bearing section 38.

[0092] The coupling section 44 is also positioned radially outward on the head section 42.

[0093] The coupling section 44 serves two different functions.

[0094] On the one hand, the coupling section 44 is designed to introduce an actuating force generated by the actuator unit 32 into the blocking element 26 so that the head section 42 can engage with the saw blade 12.

[0095] Secondly, the coupling section 44 serves to fix or lock the blocking element 26 relative to the frame 20, at least in the normal position shown in Figures 3 and 4. Thus, the head section 42 is prevented from engaging the saw blade 12 in the normal position. The force application and locking functions can be implemented separately or together, i.e., combined. The latter is the case in the embodiments according to Figures 1 to 10.

[0096] Here, the coupling section 44 comprises two coupling openings 46.

[0097] In addition, a U-shaped form-locking element 48 is provided, which on the one hand is fastened to the actuator unit 32, e.g., in a form-fitting manner, and on the other hand has nubs complementary to the coupling openings 46, which engage in the coupling openings 46. The form-locking element 48 is thus positively coupled to both the blocking element 26 and the actuator unit 32.

[0098] Thus, on the one hand, an actuating force generated by the actuator unit 32 can be introduced into the blocking element 26 via the positive-locking element 48. On the other hand, the blocking element 26 is locked in the normal position relative to the frame 20 via the positive-locking element 48 and the actuator unit 32.

[0099] It is understood that, alternatively, the coupling openings 46 and the associated nubs can also be omitted. Instead of the U-shaped form-locking element 48, a similarly U-shaped clamping element is then used, which is clamped onto the coupling section 44, i.e., is non-positively connected to the blocking element 26 in the region of the coupling section 44. Such a clamping element can be attached to the actuator unit 32 in a form-fitting or non-positive manner.

[0100] The head portion 42 further comprises a cut zone 50.

[0101] In the illustrated embodiment, the incision zone 50 is characterized by a two-row pattern of through-openings 52. For clarity, only some of the through-openings 52 are provided with a reference symbol in the figures.

[0102] By means of the through openings 52, the material of the head section 42 is specifically weakened in the area of ​​the incision zone 50, so that after the emergency brake unit 24 is triggered, the saw blade 12 cuts gently into the head section 42 over as large an area as possible.

[0103] This results in a reliable coupling between the saw blade 12 and the blocking element 26, which is necessary for reliably braking a rotation of the saw blade 12.

[0104] A connection zone 54 is provided essentially between the coupling section 44 and the incision zone 50.

[0105] In the illustrated embodiment, the connection zone 54 also includes through-openings 56. Again, for the sake of clarity, only some of the through-openings 56 are provided with a reference symbol in the figures. However, the diameters of the through-openings 56 of the connection zone 54 are selected to be significantly larger than the diameters of the through-openings 52 of the incision zone 50.

[0106] The connection zone 54 serves, on the one hand, to transmit an actuating force from the coupling section 44 to the incision zone 50. On the other hand, the incision zone 50 is coupled to the deformation section, which will be explained below, via the connection zone 54.

[0107] In this context, the through openings 56 of the connection zone 54 serve to ensure sufficient rigidity of the connection zone 54 with the lowest possible mass and thus the lowest possible mass inertia.

[0108] In addition, the head section 42 is equipped with a guide surface 58.

[0109] The guide surface 58 rests against a guide counter surface 60 of the guide element 36.

[0110] Due to the geometry of the head section 42 and the guide counter surface 60, the head section 42 is subjected to a force in the direction of the saw blade 12 when it is moved clockwise along the circumferential direction U of the saw blade 12 in the illustration according to Figure 4. For this purpose, the guide surface 58 has a normal with a radially outward extension component. As is clear from the above explanations, through openings are used in the head section 42 shown in the figures in order to create regions of different stiffness and different resistance to cutting by the saw blade 12. It is understood that, as an alternative to the through openings, this can also be achieved by providing different materials in the various regions of the head section 42. In this context, it may be particularly important to use materials of different ductility.

[0111] Located between the head portion 42 and the bearing portion 38, the blocking element 26 comprises a deformation portion 64.

[0112] The deformation section 64 connects the bearing section 38 and the head section 42 to each other.

[0113] The deformation section 64 is overall arc-shaped, in the illustrated embodiment circular arc-shaped.

[0114] In this case, an arcuate circumferential direction 66, ie the curved longitudinal extension direction of the arcuate deformation section 64, runs essentially parallel to the circumferential direction U of the saw blade 12.

[0115] In the illustrated embodiment, an outer circumference of the saw blade 12 and the arcuate deformation section 64 also run concentrically, with the central axis A representing the center.

[0116] In the embodiment shown in Figure 4, the deformation section 64 extends over a section of the arc circumferential direction 66 with a center angle of approximately 60 degrees.

[0117] The circumferential extent of the deformation section 64 is thus essentially twice the circumferential extent of the head section 42. The head section 42 is consequently circumferentially shorter than the deformation section 64. Also with respect to a circumferential extent of the bearing section 38, the deformation section 64 is several times longer.

[0118] In addition, the deformation section 64 is spaced further from the outer circumference of the saw blade 12 in a radial direction with respect to the central axis A of the saw blade 12 than the head section 42 and the bearing section 38.

[0119] In other words, both the head portion 42 and the bearing portion 38 project radially inward relative to the arc circumferential direction 66 relative to the deformation portion 64.

[0120] In this context, the radial distance D of the deformation section 64 from the saw blade 12 is selected such that it is greater than zero in all operating situations of the emergency brake unit 24. This applies in particular to an end position of the blocking element 26, which will be explained later.

[0121] In other words, the distance D of the deformation section 64 is selected such that it does not contact the outer circumference of the saw blade 12 in any operating situation.

[0122] The deformation section 64 further comprises a structure 68 that is plastically deformable in the arc circumferential direction 66.

[0123] In the embodiment shown in Figure 4, this structure 68 is formed from a total of eleven ring segments 70.

[0124] The ring segments 70 are arranged adjacent to one another along the arc circumferential direction 66 with a slight overlap.

[0125] Each of the ring segments 70 has a wall 72 with a substantially constant wall thickness t.

[0126] The walls 72 each define an axially continuous cavity 74. For the sake of better clarity, only some of the ring segments 70 as well as only some of the walls 72 and some of the cavities 74 are provided with a reference symbol in the figures.

[0127] The structure 68 which is plastically deformable in the circumferential direction 66 of the arc thus comprises a total of eleven cavities 74 arranged adjacently along the circumferential direction 66 of the arc.

[0128] Due to the slight overlap of the ring segments 70, each cavity 74 has a crescent-shaped cross-section.

[0129] Furthermore, a filling material 76 is arranged in the interior of each of the three cavities 74 which are arranged adjacent to the bearing section 38.

[0130] In the embodiment shown, the filling material is a rubber material.

[0131] Furthermore, the blocking element 26 is made of an aluminum alloy.

[0132] Due to the filling material 76, a different stiffness of the deformation section 64 results in the region of the cavities 74 provided with the filling material 76 than in the region of the unfilled cavities 74. The deformation section 64 thus comprises two regions with different stiffnesses or, more generally, a stiffness curve.

[0133] It is understood that the stiffness can be specifically adjusted by appropriately selecting the filling material 76 as well as the number and position of the cavities 74 filled with the filling material 76.

[0134] The structure 68 has the overall effect that a stiffness of the deformation section 64 along the arc circumferential direction 66 is smaller than a stiffness of the head section 42.

[0135] In addition, the structure 68 has predetermined deformation points 78. In the embodiment shown in Figure 4, these are located in the radially inwardly projecting and radially outwardly projecting sections of the ring segments 70.

[0136] For the sake of clarity, only some of the desired deformation points 78 are provided with a reference symbol in the figures. The deformation section 64 is therefore designed to be plastically shortened along the arc circumferential direction 66 to brake the saw blade 12. This is explained below with reference to Figures 5 to 8.

[0137] In this context, Figure 5 shows the emergency brake unit 24, and in particular the blocking element 26, in the previously described normal position. This means that the actuator unit 32 has not yet been actuated to effect emergency braking.

[0138] Accordingly, no force acts on the blocking element 26 (see Figure 9).

[0139] As already explained, the blocking element 26 is held in the normal position via the form-locking element 48 and the actuator unit 32.

[0140] The position in Figure 5 corresponds to the situation at 0 milliseconds in the diagram in Figure 9.

[0141] It is now assumed that the emergency brake unit 24 is triggered at time zero milliseconds (0 ms). This results in the actuator unit 32 being actuated and the head section 42 being forced toward the saw blade 12. In the illustrated embodiment, this is done via the positive locking element 48.

[0142] It is understood that at the same time the drive motor M is deactivated and / or decoupled from the drive shaft 22.

[0143] Figure 6 depicts a situation occurring one millisecond (1 ms) after triggering. Again, the force curve at 1 ms in Figure 9 can be associated with the situation in Figure 6.

[0144] In this situation, the saw blade 12 has cut into the incision zone 50, creating a force coupling between the saw blade 12 and the blocking element 26. Due to the clockwise rotation of the saw blade 12, at the time shown in Figure 6, the head section 42 has already been driven along the circumferential direction U of the saw blade 12 by a certain circumferential distance compared to the initial situation in Figure 5. This has resulted in the connection between the positive-locking element 48 and the actuator unit 32 being released.

[0145] The coupling between the form-locking element 48 and the head section 42 has remained intact in the present case.

[0146] It is understood that alternatively, the connection between the form-locking element 48 and the head portion 42 can be separated and the connection between the form-locking element 48 and the actuator unit 32 can be maintained.

[0147] In this context, the guide element 36 ensures that the blocking element 26 cannot escape the drive of the saw blade 12 either in the radial direction or in the axial direction. The blocking element 26 is thus guided along the guide direction F by means of the guide element 36.

[0148] The entrainment by the saw blade 12 has further caused at least those three ring segments 70 which are arranged adjacent to the head section 42 to be deformed.

[0149] More precisely, these ring segments were compressed along the arc circumferential direction 66.

[0150] In Figure 7, the emergency brake unit 24 is shown after a further millisecond, ie 2 milliseconds after triggering.

[0151] The head section 42 remains coupled to the saw blade 12.

[0152] Now, however, all ring segments 70 are compressed along the arc circumferential direction 66, so that the deformation section 64 is already significantly plastically shortened along the arc circumferential direction 66.

[0153] The kinetic energy of the rotation of the saw blade 12 is converted into the plastic shortening of the deformation section 64 in order to slow down the saw blade 12.

[0154] Figure 8 shows the emergency brake unit 24 five milliseconds (5 ms) after activation. At this point, the saw blade 12 is essentially stationary, i.e., it is no longer rotating. The deformation section 64 is now essentially completely compressed, i.e., the cavities 74 are essentially closed by the deformation section 64 being pushed together along the arc circumferential direction 66.

[0155] Figure 8 shows the emergency brake unit 24 at the end of an emergency braking operation. The corresponding position of the blocking element 26 is also referred to as the end position.

[0156] In order to be able to put the emergency brake unit 24 and the sawing device 10 as a whole back into operation, ie in order to make a sawing device 10 whose emergency brake unit 24 has been triggered ready for use again, the blocking element 26 must now be replaced.

[0157] For this purpose, the blocking element 26 can optionally be removed from the frame 20 separately from the actuator unit 32. The blocking element 26 can thus be removed individually. This is explained in connection with Figure 10.

[0158] As already mentioned, the blocking element 26 is rotatably mounted on the frame 20 via the fixed bearing pin 30.

[0159] In order to prevent the blocking element 26 from being separated from the bearing pin 30 along an axial direction, a holding element 80 is provided for holding the blocking element 26 on the bearing pin 30.

[0160] In the illustrated embodiment, this holding element 80 is a side wall section of the guide element 36, ie a section of a wall of the guide element 36 which prevents axial displacement of the blocking element 26.

[0161] When the guide element 36 is in its operating position shown in dashed lines in Figure 10, the blocking element 26 is consequently held on the bearing pin 30.

[0162] The guide element 36 is rotatably mounted on the frame 20 via a further bearing element 82, which is also designed as a bearing pin.

[0163] This allows the guide element 36 to be moved into a release position for disassembling the blocking element 26, which is shown in solid lines in Figure 10. In the release position, the retaining element 80 is removed from the bearing element, i.e., from the bearing pin 30.

[0164] To prevent the guide element 36 from undesirably assuming the release position, it can be locked in the operating position by means of a locking mechanism 84 (see Figure 10 and Figure 3).

[0165] The locking mechanism 84 includes a first through-opening 86 on the guide element 36 and a second through-opening 88 on the frame 20.

[0166] Furthermore, the locking mechanism 84 has a locking pin 90.

[0167] At a first end, the locking pin 90 is equipped with locking wings 92 and at a second end opposite the first end with an operating lever 93.

[0168] The locking pin 90 can thus be inserted into the through openings 86 and 88 and moved by means of the operating lever 93 into a rotational position in which the locking wings 92 engage behind a section of the frame 20.

[0169] In another rotational position, the engagement is released so that the locking pin can be pulled out axially from the through openings 86 and 88.

[0170] By means of the locking mechanism 84, the guide element 36 can be selectively locked to the frame 20 and selectively unlocked from the frame 20. This naturally also applies to the holding element 80 formed by the guide element 36.

[0171] No tools are required to operate the locking pin 90 and thus to dismantle the blocking element 26.

[0172] For the singular disassembly of the blocking element 26, only the locking pin 90 is unlocked and removed from the frame 20. The guide element 36 is then moved into the release position, and the blocking element 26 is pulled off the bearing pin 30 along an axial direction, i.e., disassembled from the frame.

[0173] Next, an unused blocking element 26 is mounted. For this purpose, the bearing section 38 of the unused blocking element 26 is placed onto the fixed bearing pin 30.

[0174] Furthermore, the unused blocking element 26 is coupled to the actuator unit 32.

[0175] The guide element 36 is then moved back into the operating position and locked there by means of the locking pin 90.

[0176] Furthermore, the actuator unit 32 must be reset to its original position. This can be done using the control unit 34.

[0177] The sawing device 10 is now ready for operation again and the emergency brake unit 24 is ready for use again.

[0178] In the emergency brake unit 24 shown in Figures 1 to 10, the head section 42 is always selectively brought into engagement with the saw blade 12 by the actuator unit 32 and is also held in the normal position by the actuator unit 32 in such a way that the head section 42 does not inadvertently come into contact with the saw blade 12.

[0179] Figures 11 to 14 show alternatives for locking the blocking element 26 in the normal position. As before, the force is applied via a pressure piece coupled to the solenoid of the actuator unit 32, which is designed to apply an actuating force to the head section 42 in the direction of the saw blade 12. The pressure piece can be designed as a plunger.

[0180] In this context, in the alternative according to Figure 11, the blocking element 26 is held in the normal position by means of a spring-loaded pin 94. For this purpose, the spring-loaded pin 94 engages in an associated recess 96 on a circumferential end face of the blocking element 26.

[0181] The actuator unit 32 corresponds to the actuator unit 32 of the embodiment shown in Figures 1 to 10. When triggered, it pushes the blocking element 26 toward the saw blade 12. This pushes the pin 94 out of the recess 96 against the spring force. In the alternative according to Figure 12, a magnet 98 and a counterpart 100 made of ferromagnetic material are provided. In the example shown, the magnet is attached to the guide element 36, and the counterpart 100 is attached to the head section 42 of the blocking element 26.

[0182] The pairing of magnet 98 and counterpart 100 is selected such that by means of the actuator unit 32 the head section 42 and thus the counterpart 100 can be detached from the magnet 98 against a magnetic force when the emergency brake unit 24 is actuated.

[0183] In the alternative according to Figure 13, a leaf spring element 102 is attached to the frame 20 via a first end. A second end of the leaf spring element 102 is received in a recess 104 arranged on the front side of the blocking element 26. This holds the blocking element 26 in the normal position.

[0184] The actuator unit 32 again corresponds to the actuator unit 32 of the embodiment from Figures 1 to 10. If this is triggered, it presses the blocking element 26 in the direction of the saw blade 12. This deforms the leaf spring element 102 so that its free end jumps out of the recess 104 and releases the blocking element.

[0185] In the alternative of Figure 14, two balls 106, 108 are provided, each engaging at different ends of one of the coupling openings 46.

[0186] The balls 106, 108 are spring-loaded so that when the actuator unit 32 is actuated they can be forced out of the coupling openings 46 and thus release the blocking element 26.

[0187] Figure 15 shows sections of an alternative sawing device 10.

[0188] In the following, only the differences from the previously explained sawing devices 10 will be discussed. Identical or corresponding elements are provided with the same reference numerals.

[0189] The differences concern the blocking element 26. Unlike in the previous embodiments, the deformation section 64 now comprises hexagonal ring segments 70. This means that the walls 72 of the ring segments 70 each form hexagons and the through openings 74 defined by these walls 72 each have a hexagonal cross-section.

[0190] A further difference is that two radially adjacent rows of ring segments 70 are now provided. Each of these rows of ring segments 70 also has 16 ring segments 70. Thus, more ring segments 70 are provided in each row than, for example, in the blocking element 26 of Figure 4.

[0191] The plastically deformable structure 68 of the blocking element 26 from Figure 15 can also be referred to as a honeycomb structure.

[0192] For the sake of clarity, only some of the ring segments 70 as well as only some of the walls 72 and some of the cavities 74 are provided with a reference symbol.

[0193] The desired deformation points 78 are now formed by those sections of the walls 72 of each ring segment 70 which comprise the radially inwardly projecting corner of the hexagonal cross-section and the radially outwardly projecting corner of the hexagonal cross-section.

[0194] Each ring segment 70 thus comprises two desired deformation points 78, one radially inner and one radially outer.

[0195] The through-holes in the head section 42, more precisely the through-holes 56 in the connection zone 54, now also have hexagonal cross-sections. Furthermore, they are arranged slightly differently than in the blocking element 26 shown in Figure 4.

[0196] Another alternative sawing device 10 is shown in sections in Figure 16.

[0197] Again, only the differences to the previous embodiments are explained.

[0198] The sawing device 10 shown in Figure 16 has a significantly smaller saw blade 12 than the previously described sawing devices. The blocking element 26 does not differ in shape from the blocking element 26 shown in Figure 10. It has simply been scaled proportionally.

[0199] This can be seen in particular by comparing the size of the blocking element 26 and the actuator unit 32, which is identical in the embodiments according to Figures 10 and 16.

[0200] Another alternative sawing device 10 is shown in sections in Figure 17.

[0201] Again, only the differences from the previous embodiments will be discussed. These again concern the blocking element 26.

[0202] In the embodiment according to Figure 17, the head portion 42 of the blocking element 26 is designed differently.

[0203] On the one hand, its front side is no longer pointed, but blunt.

[0204] On the other hand, compared to the previous head sections 42, this is longer along the arc circumferential direction 66.

[0205] This also entails an increased number as well as changes in the size and position of the through holes 56 in the connecting section 54.

[0206] Since the total length of the blocking element 26 along the arc circumferential direction 66 has remained the same, the deformation section 64 is now shorter. It now comprises only a total of seven ring segments 70. The wall thickness t of the associated walls 72 has been increased compared to the embodiment shown in Figure 4.

[0207] For the sake of clarity, only some of the ring segments 70 as well as only some of the walls 72 and some of the cavities 74 are provided with a reference symbol.

[0208] An additional embodiment of a sawing device 10 is shown in Figure 18.

[0209] The sawing device 10 is now designed as a table saw.

[0210] Otherwise, particularly with regard to the emergency brake unit 24, the above explanations apply analogously. It should be noted that in all of the aforementioned embodiments, the actuator unit 32 can also be selectively removed individually from the frame 20. This allows for easy repair of the emergency brake unit 24 in the event of a defect in the actuator unit 32. The actuator unit 32 can also be removed without tools.

[0211] List of reference symbols

[0212] 10 sawing device

[0213] 12 saw blades

[0214] 14 Basic assembly

[0215] 16 Arm assembly

[0216] 18 support surface

[0217] 20 frames

[0218] 22 Drive shaft

[0219] 24 emergency braking unit

[0220] 26 Blocking element

[0221] 28 bearing element

[0222] 30 bearing bolts

[0223] 32 Actuator unit

[0224] 34 Control unit

[0225] 36 Guide element

[0226] 38 Storage section

[0227] 40 Warehouse opening

[0228] 41 wall

[0229] 42 head section

[0230] 44 coupling section

[0231] 46 coupling openings

[0232] 48 Form-locking element

[0233] 50 incision zone

[0234] 52 passage opening

[0235] 54 Connection zone

[0236] 56 passage opening

[0237] 58 guide surface

[0238] 60 Guide counter surface 64 Deformation section

[0239] 66 Arc circumferential direction

[0240] 68 plastically deformable structure

[0241] 70 ring segment

[0242] 72 Wall

[0243] 74 Cavity

[0244] 76 Filling material

[0245] 78 Target deformation point

[0246] 80 holding element

[0247] 82 bearing element

[0248] 84 Locking mechanism

[0249] 86 first passage opening

[0250] 88 second passage opening

[0251] 90 locking pin

[0252] 92 locking wings

[0253] 93 Control lever

[0254] 94 pen

[0255] 96 Deepening

[0256] 98 Magnet

[0257] 100 counterpart

[0258] 102 leaf spring element

[0259] 104 Deepening

[0260] 106 ball

[0261] 108 ball

[0262] A Center axis of the saw blade

[0263] D radial distance of the deformation section from the saw blade

[0264] M drive motor

[0265] U Circumferential direction of the saw blade F Guide direction

[0266] G Area for a housing part not shown t Wall thickness

Claims

Patent claims 1. Locking element (26) for an emergency braking unit (24) of a sawing device (10) with a circular disc-shaped saw blade (12), wherein the locking element (26) comprises: - a bearing section (38) via which the locking element (26) can be stored on the sawing device (10), - a head section (42) designed to selectively engage the saw blade (12) for braking purposes, and - a deformation section (64) located between the bearing section (38) and the head section (42) and / or connecting the bearing section (38) and the head section (42), wherein the deformation section (64) is arc-shaped and is designed to be plastically shortened along an arc circumferential direction (66) to brake the saw blade (12).

2. Blocking element (26) according to one of the preceding claims, wherein the head section (42) is shorter along the arc circumferential direction (66) than the deformation section (64).

3. Blocking element (26) according to one of the preceding claims, wherein the head section (42) projects radially inwards relative to the deformation section (64) with respect to the arc circumferential direction (66).

4. Blocking element (26) according to one of the preceding claims, wherein the head section (42) has a greater stiffness along the arc circumferential direction (66) than the deformation section (64).

5. Blocking element (26) according to one of the preceding claims, wherein the deformation section (64) comprises a structure (68) that is plastically deformable in the circumferential direction (66) and has predetermined deformation points (78).

6. Blocking element (26) according to one of the preceding claims, wherein the deformation section (64) has a plurality of cavities (74) arranged adjacent to each other along the arc circumferential direction (66).

7. Blocking element (26) according to claim 6, wherein the cavities (74) extend axially in a direction which is axial with respect to the arc circumferential direction (66).

8. Blocking element (26) according to claim 6 or 7, wherein at least one cavity (74) is bounded by a wall (72) with constant wall thickness (t).

9. Blocking element (26) according to one of claims 6 to 8, wherein the cavities (74) are formed by adjacently arranged ring segments (70).

10. Blocking element (26) according to one of the preceding claims, wherein the deformation section (64) has a stiffness profile.

11. Sawing device (10) with a circular disk-shaped saw blade (12) and an emergency braking unit (24), wherein the emergency braking unit (24) comprises a locking element (26) according to one of the preceding claims, which is mounted on the sawing device (10) in such a way that it can selectively engage in the saw blade (12) to brake the saw blade (12).

12. Sawing device (10) according to claim 11, wherein the blocking element (26) is arranged in a normal position parallel to a circumference of the saw blade (12).

13. Sawing device (10) according to claim 12, wherein in the normal position a radial distance (D) of the deformation section (64) from the saw blade (12) is greater than a radial distance of the head cut (42) from the saw blade (12).

14. Sawing device (10) according to one of claims 11 to 13, wherein in an end position of the blocking element (26) the deformation section (64) is radially spaced from the saw blade (12).

15. Sawing device (10) according to one of claims 11 to 14, wherein the blocking element (26) can optionally be removed separately from the sawing device (10) by an actuator unit (32).

Images