Energy store comprising composite material, and tool having energy store comprising composite material

Abstract

A tool for driving a fastening element into a substrate, wherein the tool comprises an energy transmission system; wherein the energy transmission system comprises an energy store for storing mechanical energy in the tool; and wherein the energy store comprises a bending spring and a composite material.

Description

A first aspect of the invention comprises a tool for driving a fastening element into a substrate, comprising an energy transfer system, wherein the energy transfer system comprises an energy storage device for storing mechanical energy in the tool, wherein the energy storage device comprises at least one bending spring and a composite material. At least one technical effect of the aspect is that a bending spring, which preferably comprises a composite material, can be constructed compactly or spatially optimized, thus enabling access to more - in particular difficult - fastening points. The tool therefore covers a wider range of applications compared to state-of-the-art devices of the same type. An additional technical effect is that the integration of the bending spring into the energy transfer system allows significantly higher driving energies to be achieved than with conventional tools of the type in question. The additional technical effect also expands the application area of the tool. The term “bending spring” comprises, among other things, springs that can be subjected to compressive and / or tensile loads. In the context of the invention, C-springs, coil springs, compression meander springs and tension meander springs are considered to be “bending springs”. The tool comprises at least one bending spring, but it can also comprise between two and six bending springs, in particular four bending springs. The term “composite material” comprises, among other things, fibers and a matrix material. The fibers and the matrix material may be present separately and only mixed during the manufacturing process of the energy storage device. The technical effect of the fibers is that they absorb tensile and compressive stresses. The technical effect of the matrix is that it absorbs shear stresses. However, it is also possible that fibers and the matrix material are mixed before the manufacturing process. This is known as a prepreg material. Preferably, unidirectionally aligned fibers are used in prepreg materials. Advantageously, the fibers are oriented in the direction of maximum compressive and tensile stress. The technical effect of the unidirectionally aligned fibers is that the tensile and compressive strength of the bending spring is increased. The fiber content is between 35% and 75%, in particular, between 45% and 65%. In a further embodiment, the invention comprises a tool which has an energy storage device with an energy density of at least 500 J / kg. The term “energy density” comprises, among other things, the amount of energy that can be temporarily stored in the energy storage device per kilogram of its own weight and / or transferred from the energy storage device to the fastening element. Alternatively, the invention comprises a tool, wherein the energy storage device has an energy density of at least 600 J / kg, preferably of at least 650 J / kg, further preferably of at least 750 J / kg, particularly preferably of at least 950. At least one technical effect of this further embodiment and these alternatives is that the driving energy can be increased while simultaneously reducing the weight. In a further embodiment, the invention comprises an energy transfer system comprising at least one roller holder for supporting the bending spring in the tool, wherein the bending spring comprises a bearing contact surface for contacting the bending spring with the roller holder. The term “bearing contact surface” comprises, among other things, a surface section on the bending spring which is designed to be in contact with, i.e., to touch, a part of the roller holder. The bearing contact surface may be located on one and / or different sections of the bending spring. Alternatively, the invention comprises a tool, wherein the bearing contact surface of the bending spring is flat, concave or convex. At least one technical effect of this further embodiment and the alternative is that the bending spring and thus the energy storage device can be installed in the tool without the bending spring and thus also the energy storage device requiring a dedicated element for mounting in the tool. This results in a smaller and lighter tool. Another technical effect is that the relative position of the roll holder within the housing of the tool can be changed. This relative position changes whenever mechanical energy is introduced into or removed from the energy storage device. In a further embodiment, the invention comprises a tool, wherein the roller holder comprises a bearing element, so that a relative movement between the bearing contact surface of the bending spring and the outer surface of the bearing element in a circumferential direction of the bearing element is possible. The term “bearing element” comprises, among other things, a cylindrical body on whose outer surface, i.e., in a circumferential direction of the bearing element, the bending spring and the bearing element can move relative to each other. In addition, the “bearing element” may also comprise a non-ideal cylindrical body outside the contact surface with the bending spring, which may deviate from the cylindrical shape for manufacturing reasons. Alternatively, the invention comprises a tool, wherein the outer surface of the bearing element is flat, concave or convex. At least one technical effect of this further embodiment and the alternative is that the roller holder for supporting the bending spring and thus the energy storage device can be easily implemented in the tool. This results in a smaller and lighter tool. In a further embodiment, the invention comprises a tool, wherein the energy transfer system comprises at least one support bracket for supporting the bending spring in the tool, wherein the bending spring comprises a support contact surface for contacting the bending spring with the support bracket. The term “support bracket” comprises, among other things, an element on which the bending spring can be supported or firmly clamped so that forces can be transferred from the bending spring to the housing of the tool. The term “support contact surface” comprises, among other things, a surface section on the bending spring which is designed to be in contact with, i.e., to touch, a part of the support bracket. The support contact surface may be located on one and / or different surfaces of the bending spring. In addition, the bending spring can be supported or fixed on the support contact surface on the tool. Alternatively, the invention comprises a tool, wherein the support contact surface of the bending spring is flat, concave or convex. At least one technical effect of this further embodiment and the alternative is that the bending spring and thus the energy storage device can be installed in the tool without the bending spring and thus also the energy storage device requiring a dedicated element for supporting or fixing in the tool. This results in a smaller and lighter tool. In a further embodiment, the invention comprises a tool, wherein the support bracket comprises a support element, so that a relative movement between the support contact surface of the bending spring and an outer surface of the support element is possible in a circumferential direction of the support element. The term “support element” comprises, among other things, a cylindrical body on whose outer surface, i.e., in a circumferential direction of the support element, the bending spring and the support element can move relative to each other. In addition, the “support element” outside the contact surface with the bending spring may also comprise a non-ideal cylindrical body, which may deviate from the cylindrical shape for manufacturing reasons. Alternatively, the invention comprises a tool, wherein the outer surface of the support element is flat, concave or convex. At least one technical effect of this further embodiment and the alternative is that the support bracket for supporting or fixing the bending spring and thus the energy storage device in the tool can be easily implemented. This results in a smaller and lighter tool. In a further embodiment, the invention comprises a tool, wherein the support bracket is firmly connected to a housing of the tool, so that the support bracket is firmly positioned in the housing of the tool. The term “fixed position” comprises, among other things, the relative position of the support bracket within the housing of the tool. This relative position is fixed and does not change when mechanical energy is introduced into or removed from the energy storage device. At least one technical effect of this further embodiment is that the support bracket is suitable for supporting or fixing more than one bending spring. In particular, the support bracket is suitable for supporting or fixing two bending springs. This results in a smaller and lighter tool. In a further embodiment, the invention comprises a tool, wherein the bending spring has a first outer side with a first radius of curvature and a second outer side with a second radius of curvature, wherein the bending spring comprises a curved section in which the first radius of curvature and the second radius of curvature are different. The term “curved section” comprises, among other things, a partial region of the bending spring in which the first outer side has at least a first radius of curvature and the second outer side has at least a second radius of curvature. In a curved section, the first outer side may comprise two or more first radii of curvature and the second outer side may comprise two or more second radii of curvature. The first radii of curvature of the first outer side can be the same or different from each other. The second radii of curvature of the second outer side may be the same or different from each other. The beginning of a curved section occurs as soon as the radius of curvature is greater than 0 mm and less than 100 mm. The end of a curved section occurs when the radius of curvature is close to 0 mm or greater than 100 mm. The bending spring may comprise one or more curved sections. The difference between the first radius of curvature and the second radius of curvature corresponds to the spring thickness D. The spring thickness D is in the range between 3 mm and 9 mm, preferably between 5 mm and 7 mm, particularly preferably 6 mm. At least one technical effect of this further embodiment is that the size of the bending spring is reduced. This results in a smaller and lighter tool. In a further embodiment, the invention comprises a tool, wherein the curved section comprises the bearing contact surface of the bending spring and / or the support contact surface of the bending spring. At least one technical effect of this further embodiment is that the bending spring and thus the energy storage device can be installed in the tool without the bending spring and thus also the energy storage device requiring a dedicated element for mounting or support in the tool. Another technical effect is that the curved section solves two objects simultaneously. For the first alternative (bearing contact surface), the curved section provides a contact surface to the roller holder and increases the tensile and compressive strength of the bending spring. For the second alternative (support contact surface), the curved section provides a contact surface to the support bracket and increases the tensile and compressive strength of the bending spring. The technical effects mentioned lead to a smaller and lighter tool. In a further embodiment, the invention comprises a tool in which the energy transfer system comprises an energy transfer belt and the energy storage device comprises at least two bending springs. The expression “at least two bending springs” comprises, among other things, two bending springs, but also comprises more than two bending springs, for example, three, four, five, six, seven, eight, nine or ten bending springs. An even number of bending springs is preferred. At least one technical effect of this further embodiment is that the potential energy stored in the energy storage device can be evenly distributed within the tool. In addition, at least two bending springs reduce the loads caused by tensile and compressive stresses on the tool - particularly the housing of the tool. This ensures both the longevity of the tool and the required energy density of the device. The term “energy transfer band” comprises, among other things, a rope- or band-shaped transfer means as shown in DE102007000226 A1. At least one technical effect of this further embodiment is to transfer the electrical energy from the battery to the fastening element in the form of mechanical energy. In a further embodiment, the invention comprises a tool, wherein resulting forces of the at least two bending springs on the roller holder and / or on the support bracket span a plane of action W, wherein the longitudinal axis of an energy transfer element is located at least partially in this plane of action W. An even number of bending springs is preferred. At least one technical effect of this further embodiment is that the even number of bending springs acts with a direct line of force on the even number of roller holders and / or support brackets. A tensioned bending spring creates a force that moves the roller holder in the direction of movement. This prevents transverse forces and bearing friction. This leads to higher efficiency and a lighter device. An even number of springs and roller holders also allows them to move in opposite directions. This means that their inertial forces cancel each other out within the device. This reduces the recoil the user feels when driving the nail. A second aspect of the invention comprises an energy storage device for storing mechanical energy in a tool, wherein the energy storage device comprises a composite material with unidirectional fibers and a bending spring with a bearing contact surface and / or support contact surface. At least one technical effect of this second aspect is that the bending spring and thus the energy storage device can be installed in a tool without the bending spring and thus also the energy storage device requiring a dedicated element for mounting in the tool. In a further embodiment, the invention comprises an energy storage device, wherein the unidirectional fibers are aligned along a circular segment in the region of the bearing contact surface and / or the support contact surface. At least one technical effect of this further embodiment is that, due to the arrangement of the fibers, the bearing contact surfaces and the support contact surfaces of the bending spring can be used to mount the bending spring in a tool. This means that the bending spring and thus also the energy storage device can be installed in the tool without requiring a dedicated element for support, fixation or mounting in the tool. This results in a smaller and lighter tool. In a further embodiment, the invention comprises an energy storage device, wherein the unidirectional fibers are arranged in the direction of a tensile and compressive stress of the bending spring, wherein the bending spring has at least one fabric layer and / or one scrim layer, the fiber direction of which is oriented at 45° relative to the unidirectional fibers. At least one technical effect of this further embodiment is to connect the unidirectionally aligned fibers in the transverse direction in addition to the matrix material. Another technical effect is that the inclusion of air bubbles can be reduced by using fabric and / or scrim layers. This leads to lower voltage peaks in the energy storage and thus to a longer service life. In a further embodiment, the invention comprises an energy storage device, wherein the fabric layer and / or the fabric layer is arranged on an outer side of the bending spring. At least one technical effect of this further embodiment is to avoid the inclusion of air bubbles. This leads to fewer voltage peaks in the energy storage and thus to a longer service life. Further optional embodiments follow which can be combined or specified as desired with all previous embodiments of the first and second aspects and also with all further optional embodiments of the first and second aspects. In a further optional embodiment, the invention comprises a tool, wherein the energy transfer system comprises an energy storage device, a roller holder, an energy transfer belt, a spindle and an energy transfer element. The energy transfer system comprises at least one roller holder, but it may also be two, three or four roller holders. The roller holder comprises at least one roller element for guiding the energy transfer belt, but it may also be two, three or four roller elements. The roller elements represent the basic elements of the reduction gear based on a pulley system. Preferably, the tool comprises two roller holders, each with two roller elements. This results in a ratio of 1:4. The energy transfer element therefore moves four times faster than the energy storage when the bending springs relax. A high driving speed is necessary for driving fastening elements such as nails into steel or concrete substrates. Thus, the stroke of the energy transfer element is four times higher than the stroke of the energy storage device. In a further optional embodiment, the invention comprises a tool, wherein the energy storage device comprises a torsion spring. The tool comprises at least one torsion spring, but it may also comprise between 2 and 6 torsion springs, in particular 4 torsion springs. The term “torsion spring” comprises, among other things, springs that can be subjected to torsional loads. For the purposes of the invention, coil springs and torsion bars, among others, are considered to be “torsion springs”. At least one technical effect of these alternatives is that a torsion spring can be built having very little weight, thus reducing the weight of the tool. In a further optional embodiment, the invention comprises a tool, wherein the energy storage device comprises two torsion springs which are arranged one inside the other. Here, both torsion springs are connected torsionally by a common end. The inner torsion bar, for example, would be fixed against rotation at one end. The moment is transmitted through the inner torsion bar via the rotation-resistant fixation to the outer torsion bar, which in turn transmits the moment. At least one technical effect of these alternatives is that the stiffness of the rod is increased by the extension of the torsion spring. This extends the service life of the tool and makes the design of the tool more compact. In a further optional embodiment, the invention comprises a tool, wherein the fibers used may comprise glass fibers, carbon fibers or aramid fibers. Glass fibers are preferably used. At least one technical effect of these alternatives is that the elongation at break is significantly greater than, for example, with carbon fibers. In addition, prepreg layers made of glass fiber are significantly more cost-effective. This allows the spring to be made smaller and simplifies the manufacturing process. Carbon fiber-based prepreg material has at least the technical advantage of higher tensile and compressive strength and lower density compared to glass fiber-based prepreg material. In a further optional embodiment, the invention comprises a tool, wherein the composite material used comprises fibers and a thermosetting plastic, e.g. epoxy resin, or can be constructed using fibers and thermoplastic. In a further optional embodiment, the invention comprises a tool, wherein the first radius of curvature and / or the second radius of curvature lies at least in one value range from the following list: i.     5 mm to 80 mm; ii.     10.5 mm to 77 mm; iii.     11.5 mm to 76 mm; iv.    12.0 mm to 75.5 mm; v.     13 mm to 74.5 mm. At least one technical effect of this embodiment is that the first radius of curvature and / or the second radius of curvature comprise values, or lie within a range of values for radii of curvature, whereby the bending spring has a tensile and compressive strength as well as a shear strength required for a tool for driving a fastening element into a substrate. A further technical effect of this embodiment is that individualized values corresponding to the designed load can be realized for both the tensile and compressive strength as well as the shear strength. In a further optional embodiment, the invention comprises a tool, wherein the bending spring comprises a longitudinal section in which the first radius of curvature and the second radius of curvature have a value greater than 100 mm or the first radius of curvature and the second radius of curvature have the value 0 mm. The term “longitudinal section” comprises at least a partial region of the bending spring in which the first outer side has a first radius of curvature which has the value 0 mm or closely approaches this and the second outer side has a second radius of curvature which has the value 0 mm or closely approaches this. In addition, the term “longitudinal section” also comprises at least a partial region of the bending spring in which the first outer side has such a large first radius of curvature and the second outer side has such a large second radius of curvature that the partial region of the bending spring is almost flat and thus is virtually not curved. This is achieved by a value greater than 100 mm. In a longitudinal section, the first outer side comprises a first radius of curvature and the second outer side comprises a second radius of curvature. The beginning of a longitudinal section occurs when the radius of curvature is close to 0 mm or greater than 100 mm. The end of the longitudinal section occurs when the radius of curvature is greater than 0 mm and less than 100 mm. The bending spring may comprise one or more longitudinal sections. At least one technical effect of this further embodiment is that the size of the bending spring is reduced. This results in a smaller and lighter tool. In a further optional embodiment, the invention comprises a tool, wherein the bending spring has at least one section combination from the following list: i.      At least three curved sections and at least two longitudinal sections; ii.      At least four curved sections and at least three longitudinal sections; iii.     At least five curved sections and at least four longitudinal sections; iv.     At least six curved sections and at least five longitudinal sections; v.     At least seven curved sections and at least six longitudinal sections. The term “section combination” comprises at least two different sections of the bending spring - i.e., at least one curved section and at least one longitudinal section. The term “section combination” comprises both an alternating sequence of at least one curved section and at least one longitudinal section and a repeating sequence of a curved section or a longitudinal section. A combination of an alternating and repeating sequence is also covered by the term “section combination”. Alternative i) of this embodiment comprises, inter alia, three curved sections and two longitudinal sections. Two of the three curved sections may comprise a bearing contact surface of the bending spring and / or the support contact surface of the bending spring. In such a case, the bending spring of alternative i) corresponds to a single C shape with two curved sections for mounting and / or supporting the bending spring. Alternative ii) of this embodiment comprises, inter alia, four curved sections and three longitudinal sections. Two of the four curved sections may comprise a bearing contact surface of the bending spring and / or the support contact surface of the bending spring. In such a case, the bending spring of alternatives ii) corresponds to an S shape or a double C shape with two curved sections for mounting and / or supporting the bending spring. Alternative iii) of this embodiment comprises, inter alia, five curved sections and four longitudinal sections. Two of the five curved sections may comprise a bearing contact surface of the bending spring and / or the support contact surface of the bending spring. In such a case, the bending spring of alternatives iii) corresponds to an M-shape or a triple C shape with two curved sections for mounting and / or supporting the bending spring. Alternative iv) of this embodiment comprises, inter alia, six curved sections and five longitudinal sections. Two of the six curved sections may comprise a bearing contact surface of the bending spring and / or the support contact surface of the bending spring. In such a case, the bending spring of alternatives iv) corresponds to a double S shape or a quadruple C shape with two curved sections for mounting and / or supporting the bending spring. Alternative v) of this embodiment comprises, inter alia, seven curved sections and six longitudinal sections. Two of the seven curved sections may comprise a bearing contact surface of the bending spring and / or the support contact surface of the bending spring. In such a case, the bending spring of alternative v) corresponds to a five-fold C shape with two curved sections for mounting and / or supporting the bending spring. The list of alternatives to this embodiment is not exhaustive. Any n-fold C shape is feasible and encompassed by this embodiment. Basically, an n-fold C shape leads to at least n+2 curved sections and at least n+1 longitudinal sections. For example, an 8-fold C shape therefore comprises at least 10 curved sections and at least 9 longitudinal sections. At least one technical effect of this further embodiment is that the alternatives i) to v) have a specific tensile and compressive strength to ensure the required service life of the tool or the energy storage device and the bending spring. Another technical effect is that different shapes (C shape to n-fold C shape) always ensure buckling stiffness for bending springs of different sizes and lengths. This means that different energy densities of the energy storage system can be achieved and that different-sized tools can be realized - depending on the requirements profile of the device application. In a further optional embodiment, the invention comprises a tool, wherein the curved section comprises at least one curvature gradient from the following list: i.      The curvature gradient is constant; ii.     The curvature gradient increases; iii.     The curvature gradient decreases. Alternative i) of this embodiment comprises, inter alia, a curved section in which the curvature gradient does not change. Thus, both the first outer side and the second outer side always have a constant first radius of curvature and a constant second radius of curvature. In other words: In alternative i) of this embodiment, the radius of curvature within the curved section does not change for either the first outer side or the second outer side. Alternative ii) of this embodiment comprises, inter alia, a curved section in which the curvature gradient increases. Thus, the first outer side has a first radius of curvature which increases and the second outer side also has a second radius of curvature which increases. In other words: In alternative ii) of this embodiment, the radius of curvature increases at least once within the curved section. The radius of curvature - both of the first outer side and the second outer side - can also increase further within the curved section. Alternative iii) of this embodiment comprises, inter alia, a curved section in which the curvature gradient decreases. Thus, the first outer side has a first radius of curvature which decreases and the second outer side also has a second radius of curvature which decreases. In other words: In alternative iii) of this embodiment, the radius of curvature decreases at least once within the curved section. However, the radius of curvature -both of the first outer side and the second outer side - can also decrease further within the curved section. The alternatives of these embodiments can be combined as desired. For example, the curvature gradient can increase within a curved section (Alternative II), then remain constant (Alternative I) and finally decrease again (Alternative III). This example therefore shows the combination II-I-III of the alternatives of this embodiment. At least one technical effect of this optional embodiment is that the curvature gradient makes the manufacturability of the bending spring easier. A further technical effect is that a loadspecific bending spring shape can be realized. This extends the service life of the tool and makes the design of the tool more compact. At least one technical effect of this optional embodiment is that the tensile and compressive strength of the bending spring can be individualized for the load range. This extends the service life of the tool and makes the design of the tool more compact. Another technical effect is that a continuous geometry, i.e., a slowly changing curvature gradient, is aimed for to avoid stress peaks. This also extends the service life of the tool. In a further optional embodiment, the invention comprises a tool, wherein the first outer side and the second outer side are opposite each other and / or run parallel to each other. The expression “opposite each other” comprises, among other things, that the two outer sides preferably do not touch each other. The expression “parallel to each other” comprises, that the two outer sides are at the same distance from the central plane of the two outer sides. The term “central plane” comprises the plane that lies in the middle of the two outer sides. At least one technical effect of this embodiment is that a bending spring, which preferably comprises a composite material, can be constructed in a compact or spatially optimized manner and thus enables access to more - in particular to difficult - fastening points. In a further optional embodiment, the invention comprises a tool, wherein the roller holder and / or the support bracket comprise a stop surface. The term “stop surface” comprises a surface of any shape - curved, cylindrical or flat - which can stop or alternatively decelerate the movement of the bending spring along the circumferential direction of the bearing element or along the circumferential direction of the support element. At least one technical effect of this optional embodiment is that it improves the functionality of the roll holder and / or the support bracket. This improves and extends the reliability and service life of the tool. In a further optional embodiment, the invention comprises a tool, wherein the bearing element and / or the support element is designed to be fixed or rotatable. The term “fixed” comprises that the bearing element cannot rotate around its longitudinal axis. The term “rotatable” comprises that the bearing element can rotate around its longitudinal axis. At least one technical effect of this optional embodiment is that the roller holder for mounting the bending spring and / or the support bracket for supporting the bending spring and thus the energy storage device can be easily implemented in the tool. This results in a smaller and lighter tool. In a further optional embodiment, the invention comprises a tool, wherein a first longitudinal section has a greater width than a second longitudinal section and / or than at least one curved section. At least one technical effect of this optional embodiment is that shear strength in this first longitudinal section with greater width is higher than in the second longitudinal section and / or than in the at least one curved section. This increases the permissible shear stress of the bending spring and thus the service life of the tool and makes the design of the tool more compact. In a further optional embodiment, the invention comprises a tool which has a tool efficiency between 10% and 40%, preferably between 20% and 30%, particularly preferably 25%. In addition, the tool can also have a tool efficiency of 15% or 35%. The term “tool efficiency” refers to the ratio of the energy transferred to a fastening element per driving operation to the energy taken from the electrical storage of an electric battery per driving operation. This extends the battery range of the tool and means the tool battery needs to be charged less frequently. In a further optional embodiment, the invention comprises a tool which has an energy storage efficiency between 65% and 90%, preferably between 70% and 85%, particularly preferably 80%. The term “energy storage efficiency” refers to the ratio of the energy transferred to a fastening element per driving operation to the energy released as potential energy from the mechanical energy storage device per driving operation. This reduces the weight of the tool, increases the setting rate of the tool and reduces the cooling requirements of the tool. In a further optional embodiment, the invention comprises a tool, wherein the support bracket comprises at least two support contact surfaces. At least one technical effect of this optional embodiment is that at least two bending springs can be contacted or attached to a support bracket. This makes the design of the tool more compact. In a further optional embodiment, the invention comprises a tool, wherein the support bracket or the support element comprises a damper. At least one technical effect of this optional embodiment is that the force transmitted by the bending spring(s) to the support bracket or the support element is not fully transmitted to the housing of the tool but is partially absorbed by the damper. This extends the service life of the tool. In a further optional embodiment, the invention comprises a tool, wherein the longitudinal section may comprise a constant thickness and / or a converging thickness and / or a diverging thickness. The term “constant thickness” comprises that the distance of the first outer surface to the central plane and the distance of the second outer surface to the center plane can remain constant in the longitudinal section in the direction of the setting direction X. The term “converging thickness” comprises that the distance of the first outer surface to the central plane and the distance of the second outer surface to the central plane can decrease in the longitudinal section in the direction of the setting direction X. The term “diverging thickness” comprises that the distance of the first outer surface to the central plane and the distance of the second outer surface to the central plane can increase in the longitudinal section in the direction of the setting direction X. At least one technical effect of this optional embodiment is that the buckling strength of the longitudinal section and thus of the spring can be improved. This extends the service life of the tool. At least one further technical effect of this optional embodiment is that the tensile and compressive strength of the longitudinal section can be individualized depending on the load. This reduces the weight of the tool and makes the design of the tool more compact. In a further optional embodiment, the invention comprises a tool, wherein the first radius of curvature and / or the second radius of curvature comprises at least one value from the following list: i. 12 mm; ii. 15.5 mm; iii. 19 mm; iv. 22.5 mm; v. 44 mm; vi. 47.5 mm; vii. 51 mm; viii. 54.5 mm; ix. 58 mm; x. 68.5 mm; xi. 72 mm; xii. 75.5 mm. At least one technical effect of this embodiment is that the first radius of curvature and / or the second radius of curvature comprise values whereby the bending spring has a tensile and compressive strength as well as a shear strength required for a tool for driving a fastening element into a substrate. A further technical effect of this embodiment is that individualized values corresponding to the designed load can be realized for both the tensile and compressive strength as well as the shear strength. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the bending spring comprises at least one layer of fabric and / or scrim. The term “fabric” comprises, among other things, a layer which also comprises a matrix material. In contrast, the term “scrim" comprises a layer that does not contain any matrix material. At least one technical effect of this embodiment is that air bubbles trapped by the fabric and / or the scrim are better avoided in the composite material and thus stress peaks in the composite material are reduced. This increases the service life of the tool and / or the energy storage device. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the bending spring has at least one layer of fabric and / or scrim in the central plane of the bending spring. At least one technical effect of this embodiment is that the fabric and / or the scrim in the central plane of the bending spring achieves higher shear strengths by avoiding air inclusions. This increases the service life of the tool and / or the energy storage device. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the bending spring has at least one layer of fabric and / or scrim on the first and / or second outer side of the bending spring. At least one technical effect of this embodiment is that the outer sides of the bending spring are reinforced by the fabric and / or the scrim. This increases the service life of the tool and / or the energy storage device. In particular, the wear resistance in the area of the bearing element and / or the support element can be increased. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the matrix material used comprises at least one value for the shear strength from the following list: i.  80 MPa; ii.  90 MPa; iii.  100 MPa; iv.  110 MPa; v.  120 MPa; vi.  122 MPa; vii.  130 MPa. At least one technical effect of this optional embodiment is that the shear strength of the bending spring and thus also of the energy storage device and the tool is increased. This extends the service life of the tool and the energy storage unit. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the bending spring has a utilization factor of at least 0.1, preferably in the range from 0.11 to 0.5, particularly preferably in the range from 0.11 to 0.33. The term “utilization factor” describes the ratio of the stresses in the spring crosssection compared to a uniform stress distribution. The uniform stress distribution is designed to the stress for the planned service life. At least one technical effect of this optional embodiment is that the weight of the bending spring and thus of the tool can be reduced. This makes the design of the tool more compact. In a further optional embodiment, the invention comprises a tool and / or an energy storage device, wherein the fibers of the composite material have a length in the range of 20 to 300 mm and / or a width in the range of 5 to 30 mm. EXEMPLARY EMBODIMENTS The invention is explained in more detail below using exemplary embodiments with reference to the drawings. Figure 1 shows an isometric view (Figure 1a) and a side view (Figure 1b) of an embodiment of a bending spring according to the invention comprising an S shape or double C shape. Figure 2 shows an isometric view (Figure 2a) and a side view (Figure 2b) of an embodiment of a bending spring according to the invention comprising a single C shape. Figure 3 shows an isometric view (Figure 3a) and a side view (Figure 3b) of an embodiment of a bending spring according to the invention comprising an M shape or triple C shape. Figure 4 shows an isometric view (Figure 4a) and a side view (Figure 4b) of a bending spring comprising a double S shape or quadruple C shape. Figure 5 shows an isometric view (Figure 5a) and a side view (Figure 5b) of a bending spring comprising a five-fold C shape. Figure 6 shows a side view of an embodiment of a tool according to the invention comprising four bending springs, each of which has an S shape or double C shape. Figure 7 shows an isometric view (Figure 7a), a longitudinal section (Figure 7b) and a cross section (Figure 7c) of an embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has an S shape or double C shape and is arranged within the energy transfer band. Figure 8 shows an isometric view (Figure 8a) and a cross-section (Figure 8b) of an embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has an S shape or double C shape and is arranged next to the energy transfer band. Figure 9 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a single C shape and is arranged within the energy transfer band. Figure 10 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a single C shape and is arranged outside the energy transfer band. Figure 11 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a triple C shape and is arranged within the energy transfer band. Figure 12 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a triple C shape and is arranged outside the energy transfer band. Figure 13 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a quadruple C shape and is arranged within the energy transfer band. Figure 14 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a quadruple C shape and is arranged outside the energy transfer band. Figure 15 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a five-fold C shape and is arranged within the energy transfer band. Figure 16 shows a further embodiment of an energy storage device according to the invention, comprising four bending springs, each of which has a five-fold C shape and is arranged outside the energy transfer band. Figure 17 shows a further embodiment of a bending spring according to the invention comprising an S shape or double C shape, wherein the bending spring has a fabric or scrim in the central plane (Figure 17a), a fabric or scrim on the outer sides (Figure 17b) or fabric or scrim in the central plane and on the outer sides (Figure 17c). Figure 1 shows an isometric view (Figure 1a) and a side view (Figure 1b) of an embodiment of a bending spring 20 according to the invention comprising an S shape or double C shape. The bending spring 20 has a length L, a width B, and a thickness D. This embodiment comprises a first outer side 21 and a second outer side 22. In the middle of the two outer sides 21 and 22 is the central plane 25. The central plane 25 has the same distance a to the first outer side 21 and to the second outer side 22 over the entire length L. The thickness D comprises twice the distance a. The bending spring also has two surfaces 23 and 24, which can be used both as a bearing contact surface 23 and a support contact surface 24 in a tool according to the invention. In this exemplary embodiment, the bending spring comprises a surface 23, 24 on both the first outer side 21 and the second outer side 22, which surface can be used as a bearing contact surface 23 and / or support surface 24. In this example, the bearing contact surface 23 or the support contact surface 24 is concave. Figure 1 also shows an embodiment with four curved sections 27 and three longitudinal sections 28. The radii of curvature of the first outer side 21 and the second outer side 22 are clearly visible to the person skilled in the art. For reasons of clarity, the radii of curvature are not marked. Figure 2 shows an isometric view (Figure 2a) and a side view (Figure 2b) of an embodiment of a bending spring 10 according to the invention comprising a single C shape. The bending spring has a length L, a width B, and a thickness D. This embodiment comprises a first outer side 11 and a second outer side 12. In the middle of the two outer sides 11 and 12 is the central plane 15. The central plane 15 has the same distance a to the first outer side 11 as to the second outer side 12 over the entire length L. The thickness D comprises twice the distance a. The bending spring 10 also has two surfaces, which can be used both as a bearing contact surface 13 and as a support contact surface 14 in a tool according to the invention. In this exemplary embodiment, the bending spring comprises a surface on both the first outer side 11 and the second outer side 12, which can be used as a bearing contact surface 13 and / or support surface 14. In this example, the bearing contact surface 13 or the support contact surface 14 is concave. Figure 2 also shows an embodiment with three curved sections 17 and two longitudinal sections 18. The radii of curvature of the first outer side 11 and the second outer side 12 are clearly visible to the person skilled in the art. For reasons of clarity, the radii of curvature are not marked. Figure 3 shows an isometric view (Figure 3a) and a side view (Figure 3b) of an embodiment of a bending spring 30 according to the invention comprising an M shape and a triple C shape, respectively. The bending spring 30 has a length L, a width B, and a thickness D. This embodiment comprises a first outer side 31 and a second outer side 32. In the middle of the two outer sides 31 and 32 is the central plane 35. The central plane 35 has the same distance a from the first outer side 31 as from the second outer side 32 over the entire length L. The thickness D comprises twice the distance a. The bending spring also has two surfaces, which can be used both as a bearing contact surface 33 and as a support contact surface 34 in a tool according to the invention. In this exemplary embodiment, the bending spring comprises a surface on both the first outer side 31 and the second outer side 32, which can be used as a bearing contact surface 33 and / or support surface 34. In this example, the bearing contact surface 33 or the support contact surface 34 is concave. Figure 3 also shows an embodiment with five curved sections 37 and four longitudinal sections 38. The radii of curvature of the first outer side 31 and the second outer side 32 are clearly visible to the person skilled in the art. For reasons of clarity, the radii of curvature are not marked. Figure 4 shows an isometric view (Figure 4a) and a side view (Figure 4b) of an embodiment of a bending spring 40 according to the invention comprising a double S shape or quadruple C shape. The bending spring 40 comprises the length L, the width B and the thickness D. This embodiment comprises a first outer side 41 and a second outer side 42. In the middle of the two outer sides 41 and 42 is the central plane 45. The central plane 45 has the same distance a from the first outer side 41 as from the second outer side 42 over the entire length L. The thickness D comprises twice the distance a. The bending spring 40 also has two surfaces, which can be used both as a bearing contact surface 43 and as a support contact surface 44 in a tool according to the invention. In this exemplary embodiment, the bending spring 40 comprises a surface on both the first outer side 41 and the second outer side 42, which can be used as a bearing contact surface 43 and / or support surface 44. In this example, the bearing contact surface 43 or the support contact surface 44 is concave. Figure 4 also shows an embodiment with six curved sections 47 and five longitudinal sections 48. The radii of curvature of the first outer side 41 and the second outer side 42 are clearly visible to the person skilled in the art. For reasons of clarity, the radii of curvature are not marked. Figure 5 shows an isometric view (Figure 5a) and a side view (Figure 5b) of an embodiment of a bending spring 50 according to the invention comprising a five-fold C shape. The bending spring 50 has a length L, a width B, and a thickness D. This embodiment comprises a first outer side 51 and a second outer side 52. In the middle of the two outer sides 51 and 52 is the central plane 55. The central plane 55 has the same distance a from the first outer side 51 as from the second outer side 52 over the entire length L. The thickness D comprises twice the distance a. The bending spring 50 also has two surfaces, which can be used both as a bearing contact surface 53 and as a support contact surface 54 in a tool according to the invention. In this exemplary embodiment, the bending spring 50 comprises a surface on both the first outer side 51 and the second outer side 52, which can be used as a bearing contact surface 53 and / or support surface 54. In this example, the bearing contact surface 53 or the support contact surface 54 is concave. Figure 5 also shows an embodiment with seven curved sections 57 and six longitudinal sections 58. The radii of curvature of the first outer side 51 and the second outer side 52 are clearly visible to the person skilled in the art. For reasons of clarity, the radii of curvature are not marked. Figure 6 shows a first exemplary embodiment of a tool 620 according to the invention comprising an energy transfer system 600, an electrical energy source 690 (here a battery), an electric motor (not shown here) and a trigger 610. The energy transfer system 600 comprises an energy storage device - for storing mechanical energy - with four bending springs 20, each with a double C shape, two roller holders 62 with a total of four roller elements 66, i.e., two roller elements 66 per roller holder 62, an energy transfer band 67, a spindle 68 (shown here without a thread) and an energy transfer element 69 (also called a working piston) for driving a fastening element into a substrate. In order to drive a fastening element into a substrate, electrical energy is first taken from the electrical energy source 690 and fed to an electric motor (not shown here). The electric motor converts the electrical energy into a rotational movement, which in turn sets the spindle 68 into a translational movement. If the spindle 68 moves in the direction of setting direction X, the roller holders 62 and thus also their two roller elements 66 move towards each other. As a result, the four bending springs 20 of the energy storage device are compressed and store mechanical energy. The stored mechanical energy in the energy storage device is transferred to the energy transfer element 69 by actuating the trigger 610 via the energy transfer band 67 and a fastening element is driven into a substrate. Figure 7a shows an isometric view of an energy transfer system 600 according to the invention, wherein, by means of the section plane E, a section is shown along the setting direction X through the upper part of the energy transfer system 600. Figure 7b discloses the same embodiment as Figure 7a comprising a plan view of the energy storage system and the plane E (not shown in Figure 7b). Figures 7a and 7b show the same embodiment of the energy transfer system 600 as in the tool of Figure 6. The energy transfer system 600 discloses an energy storage device comprising four bending springs 20, each with a double C shape. The four bending springs 20 are arranged within the energy transfer band 67. The energy transfer system 600 also has two roller holders 62, which comprise both a bearing element 63 and two roller elements 76 each. The top view of the section plane E (Figure 7b) shows two bending springs 20, each with a double C shape. Both bending springs 20 are each mounted on a roller holder 62 and on a common support bracket 65. Figure 7b shows for each of the two bending springs 20 a bearing contact surface 23 and the corresponding, i.e. directly adjacent, surface of a bearing element 63 of the roller holder 62. The bearing element 63 and the bearing contact surface 23 are contacted with each other such that a relative movement between the bearing contact surface 23 of the bending spring 20 and the corresponding outer surface of the bearing element 63 is possible in a circumferential direction (arrow U) of the bearing element. The relative movement occurs as soon as the energy transfer system 600 absorbs or releases mechanical energy. This is the case as soon as the bending springs 20 are tensioned or relaxed. In this exemplary embodiment, the outer surfaces of the bearing element 63 are convex and the bearing contact surfaces 23 of the two bending springs 20 are concave. In Figure 7b it can be seen that each of the two bending springs 20 also has a support contact surface 24. These support contact surfaces 24 of the two bending springs 20 contact the outer surface of the support element 64 such that a relative movement between the support contact surfaces 24 of the bending springs 20 and the outer surface of the support element 64 is possible in a circumferential direction S (arrow S) of the support element. Thus, two bending springs 20 can be contacted and supported by a support element 64. This results in a smaller and lighter tool. In this exemplary embodiment, the outer surfaces of the support element 64 are convex and the support contact surfaces 24 of the two bending springs 20 are concave. The relative movements of the bending spring 20 with respect to the bearing contact surface 23 and the support contact surface 24 occur as soon as the energy transfer system 600 absorbs or releases mechanical energy. The support bracket 65 is firmly connected to the housing of the tool (see Figures 6a and 6b). Thus, the support bracket 65 is fixedly positioned in the housing of the tool and the position of the support bracket does not change even when mechanical energy is introduced into or removed from the energy transfer system. As a result, the support bracket 65 can support and / or fix the four bending springs 20 of the embodiment shown. This results in a smaller and lighter tool. Figure 7c shows another isometric view of the same energy transfer system 600 according to the invention, like Figures 7a and 7b. Figure 7c also shows a section through the energy transfer system 600 along the setting direction X by means of the plane of action W. Only the bending springs 20 are not shown in section in Figure 7c. The energy transfer system 600 discloses an energy storage device comprising four bending springs 20, each with a double C shape. The four bending springs 20 are arranged within the energy transfer band 67. Figure 7c also shows the forces F that are transferred from the four bending springs to the support element and the bearing elements. All resulting forces F lie in the same plane of action W. The longitudinal axis of the energy transfer element 69' is at least partially located in the plane of action W. Figure 8a shows an isometric view of a further embodiment of an energy transfer system 800 according to the invention. The energy transfer system 800 discloses an energy storage device comprising four bending springs 20, each with a double C shape. The four bending springs 20 are arranged outside the energy transfer belt 87. The energy transfer system 800 also has two roller holders 82, which comprise both a bearing element (not shown) and two roller elements 86 each. The bending springs 20 are each mounted on a roller holder 82 and on a common support bracket 85. The support contact surfaces 24 (not shown here) of the bending springs 20 contact the outer surface of the support element 84 such that a relative movement between the support contact surfaces 24 of the bending springs 20 and the outer surface of the support element 84 in a circumferential direction S (arrow S) of the support element 84 is possible. Thus, four bending springs 20 can be contacted and supported by a support element 84. This results in a smaller and lighter tool. In this exemplary embodiment, the outer surface of the support element 84 is convex and the support contact surfaces 24 of the bending springs 20 are concave. The relative movements of the bending spring 20 with respect to the bearing contact surface 83 and the support contact surface 84 occur as soon as the energy transfer system 800 absorbs or releases mechanical energy. The support bracket 85 is firmly connected to the housing of the tool. Thus, the support bracket 85 is fixedly positioned in the housing of the tool and the position of the support bracket does not change even when mechanical energy is introduced into or removed from the energy transfer system. As a result, the support bracket 85 can support and / or fix the four bending springs 20 of the embodiment shown. This results in a smaller and lighter tool. Figure 8b shows another isometric view of the same inventive energy transfer system 800 as Figure 8a. Figure 8b also shows a section through the energy transfer system 800 along the setting direction X by means of the plane of action W. Only the bending springs 20 are not shown in section in Figure 8b. The energy transfer system 800 discloses an energy storage device comprising four bending springs 20, each with a double C shape. The four bending springs 20 are arranged outside the energy transfer band 87. Figure 8b also shows the forces F that are transmitted by the four bending springs to the support element and the bearing elements 82. All resulting forces F lie in the same plane of action W. The longitudinal axis of the energy transfer element 89' is at least partially located in the plane of action W. Figure 9 shows an isometric view of a further embodiment of an energy transfer system 900 according to the invention. The energy transfer system 900 discloses an energy storage device comprising four bending springs 10, each having a single C shape. The four bending springs 10 are arranged within the energy transfer band 97. The energy transfer system 900 also has two roller holders 92, which comprise both a bearing element (not shown) and two roller elements 96 each. The bending springs 10 are each mounted on a roller holder 92 and on a common support bracket 95. Figure 10 shows an isometric view of a further embodiment of an energy transfer system 1000 according to the invention. The energy transfer system 1000 discloses an energy storage device comprising four bending springs 10, each having a single C shape. The four bending springs 10 are arranged outside the energy transfer belt 107. The energy transfer system 1000 also has two roller holders 102, which comprise both a bearing element (not shown) and two roller elements 106 each. The bending springs 10 are each mounted on a roller holder 102 and on a common support bracket 105. Figure 11 shows an isometric view of a further embodiment of an energy transfer system 1100 according to the invention. The energy transfer system 1100 discloses an energy storage device comprising four bending springs 30, each having a triple C shape. The four bending springs 30 are arranged within the energy transfer band 117. The energy transfer system 1100 also has two roller holders 112, which comprise both a bearing element (not shown) and two roller elements 116 each. The bending springs 30 are each mounted on a roller holder 112 and on a common support bracket 115. Figure 12 shows an isometric view of a further embodiment of an energy transfer system 1200 according to the invention. The energy transfer system 1200 discloses an energy storage device comprising four bending springs 30, each having a triple C shape. The four bending springs 30 are arranged outside the energy transfer belt 127. The energy transfer system 1200 also has two roller holders 122, which comprise both a bearing element (not shown) and two roller elements 126 each. The bending springs 30 are each mounted on a roller holder 122 and on a common support bracket 125. Figure 13 shows an isometric view of a further embodiment of an energy transfer system 1300 according to the invention. The energy transfer system 1300 discloses an energy storage device comprising four bending springs 40, each having a quadruple C shape. The four bending springs 40 are arranged within the energy transfer belt 137. The energy transfer system 1300 also has two roller holders 132, which comprise both a bearing element (not shown) and two roller elements 136 each. The bending springs 40 are each mounted on a roller holder 132 and on a common support bracket 135. Figure 14 shows an isometric view of a further embodiment of an energy transfer system 1400 according to the invention. The energy transfer system 1400 discloses an energy storage device comprising four bending springs 40, each having a quadruple C shape. The four bending springs 40 are arranged outside the energy transfer belt 147. The energy transfer system 1400 also has two roller holders 142, which comprise both a bearing element (not shown) and two roller elements 146 each. The bending springs 40 are each mounted on a roller holder 142 and on a common support bracket 145. Figure 15 shows an isometric view of a further embodiment of an energy transfer system 1500 according to the invention. The energy transfer system 1500 discloses an energy storage device comprising four bending springs 50, each with a five-fold C shape. The four bending springs 50 are arranged within the energy transfer band 157. The energy transfer system 1500 also has two roller holders 152, which comprise both a bearing element (not shown) and two roller elements 156 each. The bending springs 50 are each mounted on a roller holder 152 and on a common support bracket 155. Figure 16 shows an isometric view of a further embodiment of an energy transfer system 1600 according to the invention. The energy transfer system 1600 discloses an energy storage device comprising four bending springs 50, each with a five-fold C shape. The four bending springs 50 are arranged outside the energy transfer belt 167. The energy transfer system 1600 also has two roller holders 162, which comprise both a bearing element (not shown) and two roller elements 166 each. The bending springs 50 are each mounted on a roller holder 162 and on a common support bracket 165. Figure 17 shows another exemplary embodiment of a bending spring 170 according to the invention comprising an S shape or double C shape, wherein the bending spring 170 comprises a fabric or scrim 172 in the central plane (Figure 17a). The bending spring 180 comprises a fabric or scrim 183 on the outer sides (Figure 17b). The bending spring 190 comprises a fabric or scrim 173 in the central plane and a fabric or scrim 183 on the outer sides (Figure 17c).

Claims

1. A tool (620) for driving a fastening element into a substrate, comprising an energy transfer system (600), wherein the energy transfer system (600) comprises an energy storage device for storing mechanical energy in the tool (620), wherein the energy storage device comprises at least one bending spring (20) and a composite material, characterized in that the energy transfer system (600) comprises at least one roller holder (62) for mounting the bending spring (20) in the tool (620), wherein the bending spring (20) comprises a bearing contact surface (23) for contacting the bending spring (20) with the roller holder (62).

2. The tool (620) according to claim 1, characterized in that the energy storage device has an energy density of at least 500 J / kg.

3. The tool (620) according to the preceding claim, characterized in that the roller holder (62) comprises a bearing element (63) so that a relative movement between the bearing contact surface (23) of the bending spring (20) and an outer surface of the bearing element (63) is possible in a circumferential direction of the bearing element (63).

4. The tool (620) according to any of the preceding claims, characterized in that the energy transfer system (600) comprises at least one support bracket (65) for supporting the bending spring (20) in the tool (620), wherein the bending spring (20) comprises a support contact surface (24) for contacting the bending spring (20) with the support bracket (65).

5. The tool (620) according to the preceding claim, characterized in that the support bracket (65) comprises a support element (64) so that a relative movement between the support contact surface (24) of the bending spring (20) and an outer surface of the support element (64) is possible in a circumferential direction of the support element (64).

6. The tool (620) according to the preceding claim, characterized in that the support bracket (65) is firmly connected to a housing of the tool (620), so that the support bracket (65) is firmly positioned in the housing of the tool (620).

7. The tool (620) according to any of the preceding claims, characterized in that the bending spring (20) has a first outer side (21) with a first radius of curvature and a second outer side (22) with a second radius of curvature, wherein the bending spring (20) comprises a curved section (27) in which the first radius of curvature and the second radius of curvature are different.

8. The tool (620) according to the preceding claim, wherein the curved section (27) comprises the bearing contact surface (23) of the bending spring (20) and / or the support contact surface (24) of the bending spring (20).

9. The tool (620) according to any of the preceding claims, characterized in that the energy transfer system (600) comprises an energy transfer band (67) and the energy storage device comprises at least two bending springs (20).

10. The tool (620) according to the preceding claim, characterized in that resulting forces of the at least two bending springs (20) on the roller holder (62) and / or on the support bracket (65) span a plane of action W, wherein the longitudinal axis of an energy transfer element (69') is located at least partially in this plane of action W.

11. The tool (620) for driving a fastening element into a substrate, comprising an energy transfer system (600), wherein the energy transfer system (600) comprises an energy storage device for storing mechanical energy in the tool (620), wherein the energy storage device comprises at least one bending spring (20) and a composite material, wherein the energy transfer system (600) comprises an energy transfer band (67) and the energy storage device comprises at least two bending springs (20), wherein resulting forces of the at least two bending springs (20) on the roller holder (62) and / or on the support bracket (65) span a plane of action W, wherein the longitudinal axis of an energy transfer element (69') is located at least partially in this plane of action W.

12. The tool (620) according to claim 11, characterized in that the energy storage device has an energy density of at least 500 J / kg.

13. The tool (620) according to any of claims 11 to 12, characterized in that the energy transfer system (600) comprises at least one roller holder (62) for mounting the bendingspring (20) in the tool (620), wherein the bending spring (20) comprises a bearing contact surface (23) for contacting the bending spring (20) with the roller holder (62).

14. The tool (620) according to claim 13, characterized in that the roller holder (62) comprises a bearing element (63) so that a relative movement between the bearing contact surface (23) of the bending spring (20) and an outer surface of the bearing element (63) is possible in a circumferential direction of the bearing element (63).

15. The tool (620) according to any of claims 11 to 14, characterized in that the energy transfer system (600) comprises at least one support bracket (65) for supporting the bending spring (20) in the tool (620), wherein the bending spring (20) comprises a support contact surface (24) for contacting the bending spring (20) with the support bracket (65).

16. The tool (620) according to the preceding claim, characterized in that the support bracket (65) comprises a support element (64) so that a relative movement between the support contact surface (24) of the bending spring (20) and an outer surface of the support element (64) is possible in a circumferential direction of the support element (64).

17. The tool (620) according to the preceding claim, characterized in that the support bracket (65) is firmly connected to a housing of the tool (620), so that the support bracket (65) is firmly positioned in the housing of the tool (620).

18. The tool (620) according to any of claims 11 to 17, characterized in that the bending spring (20) has a first outer side (21) with a first radius of curvature and a second outer side (22) with a second radius of curvature, wherein the bending spring (20) comprises a curved section (27) in which the first radius of curvature and the second radius of curvature are different.

19. The tool (620) according to the preceding claim, wherein the curved section (27) comprises the bearing contact surface (23) of the bending spring (20) and / or the support contact surface (24) of the bending spring (20).

20. An energy storage device for storing mechanical energy in a tool (620), wherein the energy storage device comprises a composite material with unidirectional fibers and abending spring (20) with a bearing contact surface (23) and / or a support contact surface (24), wherein the unidirectional fibers lie in the direction of a tensile and compressive stress of the bending spring (20), characterized in that the bending spring (20) has at least one fabric layer (172) and / or a scrim layer (172) whose fiber direction is oriented 5   45° relative to the unidirectional fibers.

21. The energy storage device according to the preceding claim, wherein the unidirectional fibers are aligned along a circular segment in the region of the bearing contact surface (23) and / or the support contact surface (24).1022. The energy storage device according to the preceding claim, characterized in that the fabric layer (183) and / or the scrim layer (183) is arranged on an outer side of the bending spring (20).

Images