bolt cutters

Abstract

Bolt cutter (10) for cutting hard materials with a first lever arm (12) with a first cutting jaw (14) and a second lever arm (16) with a second cutting jaw (18), wherein the lever arms (12, 16) are pivotally connected to each other via a pivot pin (20) arranged below the cutting jaws (14, 18), so that hardened cutting edges (22, 24) of the cutting jaws (14, 18) are opposite each other, characterized in that the first lever arm (12) has a guide slot (26) in a region of the pivot pin (20) facing away from the cutting jaws (14, 18), through which the second lever arm (16) is guided.

Description

Technical field

[0001] The innovation relates to a bolt cutter for cutting hard materials with a first lever arm with a first cutting jaw and a second lever arm with a second cutting jaw, wherein the lever arms are articulated to each other via a pivot pin arranged below the cutting jaws, so that hardened cutting edges of the cutting jaws are opposite each other. Description

[0002] Bolt cutters belong to the group of hand-operated cutting tools and are used wherever high-strength materials need to be cut reliably and without an additional power source. Typical applications include metal construction, assembly and disassembly, construction sites, metalworking shops, and the work of rescue and security services. They are used in particular for cutting metal rods, chains, wire ropes, bolts, screws, or similar hard materials.

[0003] The tool operates on the principle of mechanical lever action. The ratio between the length of the lever arms and the short lever length of the cutting jaws significantly amplifies the hand force applied by the user. This high leverage allows even solid or hardened materials to be cut with comparatively little effort. The force is transmitted via the pivot pin, which connects the two lever arms.

[0004] As the lever arms close, the cutting jaws approach each other, allowing the hardened cutting edges to grip and cut through the workpiece. The cutting edges are aligned so that they face each other and move towards one another. The wedge angle of the cutting edges first scores the material to be cut, and then the tensile forces "tear" it apart. This cutting action enables a clean and controlled separation without crushing or deforming the workpiece.

[0005] The lever arms of bolt cutters are typically made of high-strength steel to reliably absorb the forces generated during the cutting process. The pivot pin is positioned to ensure stable force transmission between the lever arms and to allow the cutting jaws to move freely. The cutting jaws are often integrated as a single unit with the lever arms, but can also be designed to be replaceable for easier maintenance and resharpening.

[0006] Bolt cutters of various sizes and designs are widely used in trade and industry. While larger models are used for cutting thick steel and chains, smaller versions are intended for finer cutting work or mobile applications. All versions share a simple design, robust construction, and reliable function through purely mechanical operation.

[0007] The tool is characterized by high cutting force, precise cutting action, and reliable operation. Thanks to its simple kinematics and the robust connection of the lever arms via the pivot pin, the bolt cutter is a proven hand tool for a wide variety of applications in both professional and private settings. State of the art

[0008] From DE 37 29 436 A1, a lever-operated cutting tool, in particular a bolt cutter, is known in which two drive levers are articulated to one another via bearing journals and are supported against each other by arcuate support surfaces. Disc-shaped gear segments are arranged between the drive levers and are mounted on the bearing journals and the adjacent pivot pins of the cutting jaws via elongated recesses to ensure smooth, controlled movement of the cutting motion. A disadvantage of this known design is its comparatively complex construction with several moving elements that must be precisely aligned, which makes manufacturing costly, increases the installation space in the joint area, and promotes wear of the moving parts.

[0009] From DE 27 02 364 B2, a bolt cutter is known in which the cutting jaws are equipped with replaceable, triangular blade strips. These are attached to their end faces via a centering pin and a screw arranged coaxially to it. Although this eliminates laterally protruding clamping jaws, the attachment requires precise alignment of the centering points and is complex to manufacture. A disadvantage of this known design is that, in the case of inaccuracies in assembly, the blade strips do not rest fully on their support surfaces, which can lead to uneven loading of the cutting edges and increased wear. In addition, the structure of the cutting jaws is weakened by the necessary bores and centering points, which reduces the strength and durability of the tool under high cutting forces.

[0010] From DD 253 781 A1, a lever-operated cutting tool, in particular a bolt cutter, is known in which the cutting jaws engage in slots in the drive levers and are pivotally connected to the levers via pivot pins arranged next to the bearing journals. Disc-shaped gear segments with elongated recesses are arranged between the drive levers, ensuring symmetrical positive rotation of the cutting motion. A disadvantage of this known design is its comparatively complex construction with several components that must be precisely aligned, which makes manufacturing costly, the tool heavier, and the joint area more susceptible to wear.

[0011] Conventional bolt cutters suffer from the disadvantage that their lever arms are guided to each other only by the pivot pin at the joint. This point-contact bearing arrangement can lead to gradual wear of the bearings under heavy or repeated stress, resulting in lateral play in the lever arms. This play impairs the precise alignment of the cutting jaws and leads to increased wear on the cutting edges and joint components. Furthermore, the conventional joint arrangement requires a comparatively large amount of space for a small design, thus limiting the feasibility of compact yet robust constructions. Revelation of the innovation

[0012] The technical challenge, therefore, is to avoid the disadvantages of the prior art and to provide a bolt cutter in which the mobility of the lever arms is maintained, while simultaneously stabilizing their position relative to each other in the joint area, in order to achieve a smooth, precise, and consistent cutting motion of the cutting jaws. A robust, space-saving design suitable for manual operation should also be ensured.

[0013] In accordance with the innovation, the problem is solved by the fact that, in a bolt cutter of the type mentioned above, the first lever arm has a guide slot in an area of ​​the pivot pin facing away from the cutting jaws, through which the second lever arm is guided.

[0014] This design feature results in a particularly compact and mechanically stable construction for the bolt cutter. The guide slot enables precise and repeatable guidance of the second lever arm in the joint area, without the need for additional connecting elements or complex bearings. This allows the joint area to be designed very flat and space-saving, which significantly reduces the installation space, especially in small bolt cutters. The tool can therefore be manufactured in smaller dimensions while maintaining the same cutting force, thus reducing weight, the required hand force, and improving handling.

[0015] The compact design allows the bolt cutter to be used even in hard-to-reach places or confined work environments. At the same time, the movement of the second lever arm, positioned within the guide slot, ensures a stable relative position of the lever arms. This maintains the precise path of the cutting jaws, resulting in a smooth and accurate cutting action.

[0016] A further advantage lies in the uniform force transmission to the cutting jaws. The guide slot prevents lateral deflection or tilting of the lever arms, ensuring that the force flow is always defined via the pivot pin. This reduces wear at the bearing points, increases the tool's service life, and guarantees consistently precise cutting performance. Overall, the arrangement according to the invention results in a compact, force-optimized, and dimensionally stable design in which the lever arms retain their full range of motion, while significantly improving the cutting accuracy and durability of the tool.

[0017] An advantageous embodiment of the inventive bolt cutter provides that the pivot pin is positioned above the guide slot, facing the cutting jaws. This results in a compact design where the force transmission between the cutting jaws and the pivot pin remains short and stable. This leads to direct force transmission, reduced bending stresses in the lever arms, and an increased tool lifespan.

[0018] Another advantageous feature of the bolt cutter is the inclusion of a stop in the guide slot, which limits the movement of the second lever arm to prevent overloading of the cutting jaws. This protects the cutting edges from damage caused by excessive closing movements and simultaneously prevents overloading of the joint. This increases operational safety and extends the service life of the cutting jaws.

[0019] A practical design of bolt cutters includes a stop on at least one lever arm to protect the cutting edges. This stop prevents the cutting surfaces from colliding beyond the intended cutting point, thus protecting the cutting edges from impact loads. This ensures a consistent cutting process and extends the service life of the cutting edges.

[0020] In a preferred embodiment, the guide slot is designed as an elongated opening with substantially parallel side surfaces. This design enables smooth linear movement of the second lever arm during the cutting process and prevents jamming or tilting. This results in smooth and precise guidance of the cutting motion with reduced wear.

[0021] An advantageous further development of the inventive bolt cutter provides that the second lever arm is guided slidably in the guide slot, and the guide slot has a width that essentially corresponds to the thickness of the second lever arm. This virtually play-free fit increases lateral stability and secures the tool against unwanted movement. As a result, cutting precision is improved and the load in the joint area is distributed more evenly.

[0022] In a further embodiment of the innovative bolt cutter, the guide slot is limited by walls on both sides of the first lever arm, which serve as lateral guide surfaces for the second lever arm. This support on both sides ensures stable and torsionally rigid guidance of the second lever arm. The advantage lies in improved dimensional accuracy and consistently precise cutting.

[0023] An ergonomically and practically advantageous design feature of the bolt cutter is that the grip areas of the lever arms are ergonomically shaped and coated with non-slip materials. This makes handling safer and more comfortable, especially under high cutting force or with wet hands. At the same time, it improves power transmission, thereby reducing operating effort and increasing ergonomics.

[0024] Finally, it is advantageous if the new bolt cutter has a total length of no more than 200 mm. This compact design allows for use in confined spaces and facilitates one-handed operation. The low weight further improves handling and allows for precise positioning during the cutting process.

[0025] A further advantageous embodiment of the inventive bolt cutter provides that the guide slot has a shaped element adapted to the cross-sectional shape, in particular a T-profile, of the second lever arm passing through the slot. This positive fit allows the second lever arm to be inserted during tool assembly without elastic expansion of the first lever arm. In this way, no internal stresses arise in the slotted lever arm that could later lead to material fatigue or deformation. At the same time, precise positioning of the inserted lever arm is achieved, thereby increasing stability in the joint area and ensuring the dimensional accuracy of the connection throughout the entire service life of the tool.

[0026] Further embodiments and advantages will become apparent from the subject matter of the dependent claims and the drawings with their accompanying descriptions. One exemplary embodiment is explained in more detail below with reference to the accompanying drawing. The innovation is not intended to be limited solely to this exemplary embodiment. Rather, embodiments are also envisaged which are now and in the future equivalent and obvious to a person skilled in the art using other technical aids. The aforementioned prior art shall be deemed a disclosure to this application. Brief description of the drawing Fig. Figure 1 shows a schematic diagram of the new bolt cutter in a closed position. Fig. Figure 2 shows a schematic diagram of the new bolt cutter in an open position according to Fig. 1. Fig. Figure 3 shows the new bolt cutter in a perspective view. Fig. Figure 4 shows a section of a lever arm with a guide slot for the bolt cutter. Preferred embodiment

[0027] The Fig. Figures 1 to 4 show different views of the newly designed bolt cutter, which is intended for cutting hard materials. Identical reference numerals denote identical or equivalent parts.

[0028] Fig. Figure 1 shows the bolt cutter 10 in the closed position. The bolt cutter 10 is used for cutting hard materials, such as metal bolts, and consists of a first lever arm 12 with a first cutting jaw 14 and a second lever arm 16 with a second cutting jaw 18. The two lever arms 12, 16 are pivotally connected to each other via a pivot pin 20 located below the cutting jaws 14, 18. This arrangement places the hardened cutting edges 22, 24 of the two cutting jaws 14, 18 opposite each other, so that when the lever arms 12, 16 are brought together, a cutting motion is performed that reliably cuts the workpiece located between the cutting edges 22, 24.

[0029] The first lever arm 12 has a guide slot 26 in a region of the pivot pin 20 facing away from the cutting jaws 14, 18, through which the second lever arm 16 passes. The pivot pin 20 is positioned above the guide slot 26 in the direction of the cutting jaws 14, 18, so that the force transmission between the cutting area and the pivot remains short and stable. This arrangement contributes to a compact and force-optimized design. To protect the cutting edges 22, 24, a stop 28 can be provided on at least one of the lever arms 12, 16, which limits the maximum closing travel of the lever arms and prevents the cutting edges from colliding beyond the cutting point.

[0030] The guide slot 26 is arranged longitudinally along the first lever arm 12 and ensures that the second lever arm 16 is guided along a defined path of movement throughout the entire operation of the tool. This maintains the precise relative position of the lever arms 12 and 16, resulting in a smooth force transmission and a precise cutting motion. At the same time, the guide slot 26 contributes to a compact design of the joint area, as no additional bearings or connecting elements are required. The illustration demonstrates that, despite its robust construction, the bolt cutter 10 has a handy, space-saving form and is suitable for use in confined work environments.

[0031] Fig. Figure 2 shows the bolt cutter 10 in the open position. The function of the guide slot 26 is clearly visible here. The second lever arm 16 slides within the guide slot 26 of the first lever arm 12, while the cutting jaws 14, 18 move apart. This arrangement ensures that the cutting edges 22, 24 are always guided in a parallel plane to each other, thus achieving a uniform force distribution along the cutting edges 22, 24. In this way, wear and deformation in the joint area are reduced, and the cutting precision is maintained throughout the entire service life of the tool. A stop 30 can also be provided in the area of ​​the guide slot 26, which limits the travel of the second lever arm 16 to prevent overloading of the cutting jaws 14, 18.The grip areas 32, 34 of the lever arms 12, 16 are ergonomically shaped and provided with non-slip coatings, resulting in improved haptics, safe handling and low-loss power transmission.

[0032] In the perspective representation according to Fig. Figure 3 shows the spatial arrangement of the lever arms 12, 16 with the cutting jaws 14, 18. The guide slot 26 is elongated and its shape is adapted to the cross-sectional geometry of the second lever arm 16 passing through it. Walls 36 on both sides of the first lever arm 12 form guide surfaces that laterally support the second lever arm 16 and prevent it from tilting. The pivot pin 20 is located above the guide slot 26, ensuring that the force flow between the cutting area and the pivot remains short, direct, and mechanically stable. This design results in low-loss force transmission and reduces bending stresses in the lever arms.

[0033] Fig.Figure 4 shows a section of the first lever arm 12 with the guide slot 26 formed therein. A shaped element 38 is provided in the area of ​​the guide slot 26, the geometry of which is adapted to the cross-sectional shape, in particular a T-profile, of the second lever arm 16 passing through the guide slot 26. This positive-locking design ensures that the second lever arm 16 is precisely received in the first lever arm 12 without the need for elastic expansion or clamping during assembly. This results in stress-free assembly, thus preventing the development of internal material stresses in the area of ​​the slotted first lever arm 12. The shaped element 38 therefore guarantees a permanently dimensionally accurate and play-free connection between the two lever arms 12 and 16.Even under repeated and high mechanical stress, the position of the second lever arm 16 in the guide slot 26 remains exactly unchanged, ensuring consistently precise movement and a long service life for the joint area. The lower section of the guide slot 26 is fork-shaped to provide sufficient freedom of movement for the second lever arm 16, while the remaining walls 36 ensure stable guidance.

[0034] The bolt cutter 10 is designed as a small and easily transportable tool with a total length of up to 200 mm, resulting in a compact and handy design while maintaining high cutting force.

[0035] The figures illustrate the compact and functional design of the bolt cutter 10, in which the guide slot 26 located in the first lever arm 12 ensures a precise, backlash-free, and permanently stable connection between the lever arms 12 and 16. This design results in uniform power transmission, precise cutting action, and an overall improved service life of the tool. Reference symbol list 10 bolt cutters 12 First lever arm 14 First cutting jaw 16 Second lever arm 18 Second cutting jaw 20 joint pins 22 First cutting edge 24 Second cutting edge 26 guide slots 28 Stop on the lever arm 30 Stop in guide slot 32 First grip area 34 Second grip area 36 walls or guide surfaces 38 Form element in the guide slot QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 37 29 436 A1

[0008] DE 27 02 364 B2

[0009] DD 253 781 A1

[0010]

Claims

[1] Bolt cutter (10) for cutting hard materials with a first lever arm (12) with a first cutting jaw (14) and a second lever arm (16) with a second cutting jaw (18), wherein the lever arms (12, 16) are pivotally connected to each other via a pivot pin (20) arranged below the cutting jaws (14, 18), so that hardened cutting edges (22, 24) of the cutting jaws (14, 18) are opposite each other, characterized by , that the first lever arm (12) has a guide slot (26) in an area of ​​the pivot pin (20) facing away from the cutting jaws (14, 18), through which the second lever arm (16) is guided. [2] Bolt cutter (10) for cutting hard materials according to claim 1, characterized by , that the pivot pin (20) is arranged in the direction of the cutting jaws (14, 18) above the guide slot (26). [3] Bolt cutter (10) for cutting hard materials according to one of claims 1 or 2, characterized by, that a stop (30) is formed in the guide slot (26) which limits the movement path of the second lever arm (16) in order to prevent overstressing of the cutting jaws (14, 18). [4] Bolt cutter (10) for cutting hard materials according to one of claims 1 to 3, characterized by , that a stop (28) is provided on at least one lever arm (12, 16) to protect the cutting edges (22, 24). [5] Bolt cutter (10) for cutting hard materials according to one of claims 1 to 4, characterized by , that the guide slot (26) is designed as an elongated opening with substantially parallel side surfaces (36). [6] Bolt cutter (10) for cutting hard materials according to any one of claims 1 to 5, characterized by , that the second lever arm (16) is guided slidably in the guide slot (26) and the guide slot (26) has a width that is essentially equal to the thickness of the second lever arm (16). [7] Bolt cutter (10) for cutting hard materials according to any one of claims 1 to 6, characterized by , that the guide slot (26) is limited by walls (36) on both sides of the first lever arm (12), which are designed as lateral guide surfaces for the second lever arm (16). [8] Bolt cutter (10) for cutting hard materials according to any one of claims 1 to 7, characterized by , that the grip areas (32, 34) of the lever arms (12, 16) are ergonomically shaped and / or are provided with non-slip coatings for improved haptics and secure power transmission during the cutting process. [9] Bolt cutter (10) for cutting hard materials according to any one of claims 1 to 8, characterized by , that the bolt cutter (10) has a total length of no more than 200 mm. [10] Bolt cutter (10) for cutting hard materials according to any one of claims 1 to 9, characterized by, that the guide slot (26) has a shaped element (38) which is adapted to the cross-sectional shape, in particular a T-profile, of the second lever arm (16) passing through the guide slot (26), whereby the second lever arm (16) can be mounted without widening the slotted first lever arm (12) and no mounting or operating stresses are introduced into the slotted first lever arm (12).

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