Equipment system for hand-held power tools fitted with impact mechanisms and belonging to different performance classes

Abstract

The invention relates to an equipment system (100) for hand-held power tools (EH1, EH2, EH3; EH1', EH2', EH3', EH1'', EH2'') fitted with impact mechanisms (1) and belonging to different performance classes, wherein each hand-held power tool comprises an impact body (10) for applying impact forces to an associated tool which can be inserted into a tool holder (9) of one of the hand-held power tools; and wherein at least one of the hand-held power tools in the equipment system (100) comprises an impact body (10a, 10a'', 10b'') made of a steel material, and at least one other of the hand-held power tools in the tool system (100) comprises a hybrid impact body (10b, 10c, 10a1, 10b1, 10c1) comprising at least two different materials.

Description

[0001] 2024P00140EP

[0002] Hilti Aktiengesellschaft

[0003] Principality of Liechtenstein

[0004] DEVICE SYSTEM OF HAND TOOL MACHINES EQUIPPED WITH PERFORMANCE SYSTEMS OF DIFFERENT POWER CLASSES

[0005] DESCRIPTION

[0006] The present invention relates to a device system of hand-held power tools of different performance classes equipped with impact mechanisms, each comprising an impact body for impacting an associated tool which can be inserted into a tool holder of a hand-held power tool.

[0007] The application area of ​​the invention extends in particular to impact drills, chiseling machines, rotary hammer machines or combination hammer machines, which have in common an impact mechanism integrated into the drive train, which is preferably driven by an electric motor.

[0008] A percussion mechanism serves to convert the rotary drive motion of the drive unit into an alternating working motion for striking the tool, primarily a percussion drill or chisel. Between the percussion mechanism and the tool, a percussion element according to the invention – a so-called impactor – is arranged, which, due to its inertia, generates a sufficiently large impulse.

[0009] State of the art

[0010] According to generally known technology, the combination of high mechanical stress and high abrasive wear on an impactor leads to considerable wear of the impact surface, even when using high-grade steels. Furthermore, high-grade steels require a complex and energy-intensive heat treatment process. This, in turn, leads to increased contact stiffness, which increases the overall stress on the tool and can thus lead to premature tool failure. Since an impactor in an impact mechanism typically comes into contact with a large number of tools over its service life, the wear of the impact surface is more severe than the usual wear at the tool contact points.While there is a user tolerance for the need to replace tools due to wear, the impact elements of an impact mechanism are expected to have a long service life. Furthermore, a deformed impact element due to wear leads to increased tool wear, resulting in a poor sustainability profile.

[0011] German patent DE 10 2010 043 837 A1 discloses an electric hand tool whose impact mechanism acts on a striking body, which in turn impacts a tool. The striking body transmits the impulse via a front-facing contact surface to the coaxially arranged tool and is subjected to particularly high loads. This also applies, to a lesser extent, to the second contact surface on the opposite front face of the striking body, which interacts with the impact mechanism.

[0012] To withstand high impulse loads, the striking surface of the impactor is located on a first impactor part made of a different material than the rest of the impactor part. Alternatively, both impactor parts may be made of the same material but differ in their heat treatment. This allows the impactor part with the striking surface to be manufactured with higher impact toughness, resulting in a homogeneous impactor.

[0013] The object of the present invention is to provide a system of power tools equipped with impact mechanisms of different performance classes, by means of which optimized equipment of the power tools in the system can be achieved in a simple manner with regard to cost and service life. Disclosure of the invention

[0014] The problem is solved starting from a device system according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims specify advantageous embodiments of the invention.

[0015] The invention includes the system-technical teaching that in a device system comprising various hand-held power tools of different performance classes, at least one hand-held power tool of the device system has a striking body made of a steel material and at least one hand-held power tool of the device system has a hybrid striking body comprising at least two different materials.

[0016] This allows for a simple and cost-effective optimization of the service life of individual power tools by using an optimized impact element depending on the load. The type of impact element used in a power tool is primarily determined by its power class, meaning that higher-performance power tools typically use a hybrid impact element, while lower-performance tools use a homogeneous impact element. This results in a cost- and performance-optimized tool system.

[0017] According to an advantageous embodiment of the invention, it is proposed that the tool holders of the hand-held power tools are designed to accommodate tools with the same insertion-end geometry. In this case, at least one hand-held power tool with an insertion-end system thus has a homogeneous impact element, and at least one other hand-held power tool with the same insertion-end system has a hybrid impact element.

[0018] A tool holder system is characterized by its design for accepting tools with the same insert-side geometry. Handheld power tools for the same tool holder system therefore have correspondingly designed tool holders. The system can include handheld power tools with tool holders for, for example, so-called C-, Y-, S-, and / or H-type tool holder systems.

[0019] In an advantageous embodiment of the invention, the impact elements made of steel and the hybrid impact elements are designed with substantially the same tool-side diameters. The impact elements are, in particular, part of hand-held power tools belonging to a common class of equipment.

[0020] It may be provided that the tool holders of the hand-held power tools are designed to accommodate tools with differing insertion-end geometries, so that the device system includes hand-held power tools with, for example, so-called C, Y, S, and / or H insertion end systems. It may be provided, for example, that all hand-held power tools with one insertion end system are designed with a homogeneous impact element, and all hand-held power tools with another insertion end system are designed with a hybrid impact element, with hand-held power tools with an insertion end system designed for higher performance being designed with hybrid impact elements.

[0021] Alternatively, it may be provided that within a device class, i.e., hand-held power tools with a common shank system, at least one hand-held power tool with a homogeneous impact element and at least one hand-held power tool with a hybrid impact element are provided. Hand-held power tools of different device classes have different shank systems.

[0022] In order to enable particularly cost-effective production of the impact elements of a device system according to the invention, an advantageous embodiment of the invention provides for at least two hybrid impact elements for different hand-held power tools, i.e., for hand-held power tools of different performance classes, which are designed with identical contact elements. In this way, the number of identical parts is advantageously large, thus reducing material and / or manufacturing costs.

[0023] In an advantageous embodiment of the invention, at least one contact element of at least one hybrid striking body is designed in the form of a support or in the form of an insert.

[0024] In an advantageous embodiment of the invention, at least one hybrid striking body has a recess on its end face facing the tool for receiving the cylindrical or conical contact element, which is designed, in particular, with a convex impact surface. A conical contact element, due to its conical shape, provides a self-centering effect in the direction of impact; however, this results in an increased contact gap load on the outer surface, which can be reduced by centering strips or similar spacers projecting from the outer surface.

[0025] In an advantageous embodiment of the invention, at least one hybrid striking body has a disc-shaped contact element which is connected to the main part in the area of ​​an end face of a main part of the striking body facing the tool.

[0026] Preferably, the contact element is bonded to the end face or within the recess of the striking body. This bond can be achieved through adhesive bonding or soldering and should cover the entire contact area between the contact element and the end face / recess of the striking body, both on the end face and, if applicable, on the outer surface, to maximize holding force.

[0027] In an advantageous embodiment of the invention, the contact element consists of a metal matrix composite material comprising a cemented carbide material, preferably a tungsten carbide-cobalt cemented carbide. The metal matrix composite of the contact element preferably contains hard particles held together by a metal matrix. This results in very high impact strength. In contrast, the steel material of the remaining impact body can be conventional case-hardening steel, heat-treatable steel, or tool steel. For example, a tungsten carbide-cobalt cemented carbide (WC-Co) is suitable as the cemented carbide material used within the metal matrix composite. The WC to Co ratio is preferably greater than 6, and particularly preferably greater than 10, to achieve the desired workpiece properties.

[0028] In an advantageous embodiment of a device system according to the invention, it is provided that the impact unit of at least one hand-held power tool, preferably several hand-held power tools, and particularly preferably all hand-held power tools, is designed in the manner of a pneumatic impact mechanism, comprising an eccentric drive for converting the rotary drive movement into a linear alternating movement by means of coupling to an excitation piston with a connecting rod, which is guided slidably in a guide tube, in order to interact with an opposing impact piston via a compressible air column generated between them.

[0029] Detailed description based on drawing

[0030] Further measures improving the invention are described in more detail below, together with a description of preferred embodiments, with reference to the figures. The figures show:

[0031] Fig. 1 shows a schematic longitudinal section through an exemplary impact mechanism of a chisel hammer with a tool inserted.

[0032] Fig. 2 shows a schematically detailed longitudinal section through the striking mechanism arrangement according to Fig. 1 to illustrate the striking chain,

[0033] Fig. 3 shows a tabular representation of a device system of electric hand tools of different performance classes with homogeneous and hybrid impact elements for electric hand tools with the same insertion-side geometry,

[0034] Fig. 4 shows a tabular representation of a device system, wherein electric hand tools of different performance classes with homogeneous and hybrid impact elements are provided, wherein the device system has several device classes that include electric hand tools with different insertion-side geometries,

[0035] Fig. 5a shows a longitudinal section through a homogeneous impact body of an electric hand tool of a device class of the device system,

[0036] Fig. 5b shows a longitudinal section through a hybrid impact body of another electric hand tool of the same device class as the electric hand tool according to Fig. 5a with a disc-shaped contact element, wherein the electric hand tool is designed for the same plug-in end system as the electric hand tool according to Fig. 5a,

[0037] Fig. 5c shows a longitudinal section through a hybrid impact body of another electric hand tool of the device system with an identical disc-shaped contact element, wherein the electric hand tool is designed for the same plug-in end system as the electric hand tools according to Figs. 5a and 5b,

[0038] Fig. 6a shows a longitudinal section through a hybrid impact body of an electric hand tool of the device system with a cylindrical contact element, wherein the electric hand tool is designed for a different plug-in end system than the electric hand tools according to Fig. 5a, Fig. 5b and Fig. 5c and thus belongs to a different device class than the electric hand tools according to Fig. 5a, Fig. 5 and Fig. 5c.

[0039] Fig. 6b shows a longitudinal section through a hybrid impact body of another electric hand tool of the device system with an identical cylindrical contact element, wherein the electric hand tool is designed for the same insertion system as the electric hand tool according to Fig. 6a,

[0040] Fig. 6c shows a longitudinal section through a hybrid impact body of another electric hand tool of the device system with an identical cylindrical contact element, wherein the electric hand tool is designed for the same plug-in end system as the electric hand tools according to Figs. 6a and 6b,

[0041] Fig. 7a shows a longitudinal section through a homogeneous striking element of an electric hand tool of another device class of the device system, wherein the electric hand tool is designed for a different plug-in end system than the electric hand tools according to Fig. 5a, Fig. 5b and Fig. 5c and Fig. 6a, Fig. 6b and 6c, and Fig. 7b shows a longitudinal section through a homogeneous striking element of another electric hand tool of the device system, wherein the electric hand tool is designed for the same plug-in end system as the electric hand tool according to Fig. 7a.

[0042] According to Fig. 1, a percussion mechanism for a hand-held power tool, in particular a chisel hammer, essentially consists of a percussion unit 1 for converting a rotary drive motion of a drive unit designed as an electric motor 2 into a linear alternating working motion for a tool 3, which here is designed as a chisel. The pneumatic percussion unit 1 comprises an eccentric drive 4 for converting the rotary drive motion generated by the electric motor 2 into the linear alternating motion by coupling it to an exciter piston 5 with a connecting rod 6. The exciter piston 5 is guided slidably in a guide tube 7, forming a piston-cylinder unit. Opposite the exciter piston 5, a percussion piston 8 is arranged, also slidably in the guide tube 7.A damping column of air is generated between the exciter piston 5 and the impact piston 8 as a result of the linearly alternating movement.

[0043] The impact unit 1 acts on an adjacent impact body 10, made of a steel material, which is also slidably housed in an extension 9 of the guide tube 7. The impact body 10 has a rotationally symmetrical shape and, within the action chain, acts in a backward-percussive manner on the tool 3.

[0044] As shown in Fig. 2, the two end faces 11a and 11b of the impactor 10 are provided with a convex impact surface. Along the chain of action, the global stress on the impacting components is minimized. However, the local stress on the impacting components at the contact points is very high. The convexly shaped end faces 11a and 11b of the impactor 10 reduce the contact stiffness of the impact transmission and stretch the temporal contact force profile, which has a stress-reducing effect.

[0045] Figure 3 shows various electric hand tools EH1, EH2, EH3 of different performance classes, wherein the electric hand tools EH1, EH2, EH3 are part of a device class S1, which in turn is part of a device system 100. The electric hand tools EH1, EH2, EH3 are all designed to hold tools with the same insertion-side geometry and have correspondingly designed tool holders 9.

[0046] A socket system is understood to be, for example, a C, Y, S, H, or other socket system. Device class S1 thus comprises power hand tools EH1, EH2, and EH3, all of which have the same socket system or the same socket-side geometry for receiving tools. All impact elements 10a to 10c have the same end-face diameter D, so they can be combined with the same tool system WZS1. Various tools with the same connection configuration can be used within the WZS1 tool system.

[0047] Figures 5a, 5b, and 5c show the impact elements 10a, 10b, and 10c of the EH1, EH2, and EH3 power tools according to Figure 3, shown individually. The respective impact elements 10a, 10b, and 10c are designed according to their respective performance classes and may therefore have different masses and / or shapes. The impact elements 10a, 10b, and 10c have different lengths L and essentially identical diameters D in the area of ​​the end face 11a.

[0048] The impact body 10a is designed as a steel body 14a and is homogeneous, i.e., it is made of a material with essentially homogeneous material properties.

[0049] In contrast to the striking element 10a, the striking elements 10b and 10c have a hybrid shape. This means that a contact element 12b or 12c is provided on the tool side, respectively. The contact elements 12b and 12c are identical in construction, i.e., they are designed as identical parts.

[0050] The contact elements 12b and 12c are each arranged on an end face 15 of a steel main part 14b or 14c of the impact body 10b or 10c, the main parts 14b and 14c differing in shape. The contact elements 12b and 12c are disc-shaped and are bonded to the main part 14b or 14c via a flat end face 15, for example, by a soldered connection. The contact elements 12b and 12c are made of a metal imatrix composite material, in particular comprising a tungsten carbide-cobalt cemented carbide material, which ensures increased impact strength under high loads. The contact elements 12b and 12c are designed as a support and have a convex contact surface for interaction with the tool 3.

[0051] The impact elements 10a, 10b, and 10c are optimized for the specific application of the respective electric hand tools EH1, EH2, and EH3, respectively. Lower-powered electric hand tools EH1 are preferably equipped with a homogeneous impact element 10a or Döpper, while high-powered electric hand tools EH2 and EH3 are preferably equipped with a hybrid impact element 10b or 10c. This allows for the cost-effective production of lower-powered electric hand tools EH1 with a sufficient service life, while ensuring a long service life for high-powered electric hand tools EH2 and EH3.

[0052] Figure 4 shows the device system 100, in which, in addition to device class S1, further device classes S2 and S3 are shown. The device classes S1, S2 and S3 differ with regard to their plug-in terminal system or tool system WZS1, WZS2, WZS3, whereby electric hand tools with a tool system WZS1, WZS2 or WZS3 can be used with different tools of the same connection configuration.

[0053] The device class S2 comprises three electric hand tools EHT to EH3' with associated impact elements 10a' to 10c', each designed as a hybrid impact element 10a', 10b', 10c'. The impact elements 10a', 10b', 10c' of the electric hand tools EH1' to EH3' are shown in Fig. 6a, Fig. 6b and Fig. 6c and have a diameter D' which is larger than the diameter D of the electric hand tools EH1 to EH3 of device class S1.

[0054] The striking elements 10a' to 10c' are each designed as a hybrid, comprising a steel body 14a', 14b' and 14c' (main part) and a contact element 12a', 12b' and 12c' connected to the steel body 14a', 14b' and 14c'. The contact elements 12a', 12b' and 12c' are identical and are each arranged in a recess 13 of the steel body 14a', 14b' and 14c' in the region of a front end face 11a. The cylindrical contact elements 12a', 12b' and 12c' are, for example, metallurgically bonded to the steel body 14a', 14b' and 14c'.

[0055] The contact elements 12a', 12b', 12c' are each made of a metal matrix composite material comprising a tungsten carbide-cobalt hard metal material, which provides increased impact strength under high load.

[0056] The S3 device class comprises two electric hand tools, EH1" and EH2", which are designed for a further, very powerful shank-end system. The impact elements 10a" and 10b" of the electric hand tools have a face diameter D" that is larger than the diameter D and the diameter D', enabling the S3 device class electric hand tools EH1" and EH2" to impact correspondingly large tools.

[0057] The impact elements 10a" and 10b" are homogeneous. Due to their relatively high mass and voluminous shape, contact elements are not required for these heavy impact elements in the EH1" and EH2" power hand tools of equipment class S3. Reference numeral list

[0058] 1 percussion

[0059] 2 electric motors

[0060] 3 tools

[0061] 4 eccentric drives

[0062] 5 exciter pistons

[0063] 6 connecting rods

[0064] 7 Guide tube

[0065] 8 impact pistons

[0066] 9 Tool holder

[0067] 10 impact pistons

[0068] 11 Front

[0069] 12 Contact element

[0070] 13 Exclusion

[0071] 14 Main part

[0072] 15 Front

[0073] 100 device systems

[0074] Diameter

[0075] EH electric hand tools

[0076] Length L

[0077] S device class

[0078] WZS tool system

Claims

REQUIREMENTS 1. Device system (100) of hand-held power tools (EH1 , EH2, EH3; EH1', EH2', EH3', EH1“, EH2“) of different performance classes equipped with impact mechanisms (1), each comprising an impact body (10) for impacting an associated tool (3) which can be inserted into a tool holder (9) of a hand-held power tool (EH), characterized in that at least one hand-held power tool (EH) of the device system (100) has an impact body (10a, 10a“, 10b“) made of a steel material and at least one other hand-held power tool (EH) of the device system (100) has a hybrid impact body (10b, 10c, 10a', 10b', 10c') comprising at least two different materials.

2. Device system according to claim 1, characterized in that tool holders (9) of the hand-held power tools (EH) are provided for receiving tools (3) with the same insertion-side geometry.

3. Device system according to claim 1 or 2, characterized in that the impact bodies (10a, 10a“, 10b“) consisting of a steel material and the hybrid impact bodies (10b, 10c, 10a', 10b', 10c') are designed with substantially the same tool-side diameters (D; D'; D“).

4. Device system according to one of the preceding claims, characterized in that tool holders (9) of the hand-held power tools (EH) are provided for receiving tools (3) with different insertion-side geometries.

5. Device system according to one of the preceding claims, characterized in that at least two hybrid impact bodies (10b, 10c, 10a', 10b', 10c') are provided for different hand-held power tools (HP), which are designed with identical contact elements (12b, 12c or 12a', 12b", 12c').

6. Device system according to one of the preceding claims, characterized in that at least one contact element (12b, 12c; 12a', 12b', 12c') of at least one hybrid striking body (10b, 10c; 10a', 10b', 10c') is designed in the form of a support or in the form of an insert.

7. Device system according to one of the preceding claims, characterized in that at least one hybrid impact body (10a' - 10c') has a recess (13) on the end face (11a) facing the tool (3) for receiving the cylindrical or conical contact element (12a', 12b", 12c') which is designed in particular with a convex impact surface.

8. Device system according to one of the preceding claims, characterized in that at least one hybrid striking body (10b, 10c) has a disc-shaped contact element (12b, 12c) which is connected to the main part (14b, 14c) of the striking body (10b, 10c) in the area of ​​an end face (15) of a main part (14b, 14c) facing the tool (3).

9. Device system according to one of the preceding claims, characterized in that the contact element (12a - 12c; 12a'; 12b") consists of a metal matrix composite material comprising a hard metal material, preferably a tungsten carbide-cobalt hard metal material.

10. Device system according to one of the preceding claims, characterized in that the impact unit (1) of at least one hand-held power tool (HP), preferably several hand-held power tools (HP), particularly preferably all hand-held power tools (HP), is designed in the manner of a pneumatic impact mechanism, comprising an eccentric drive (4) for converting the rotary drive movement into a linear alternating movement by means of coupling to an exciter piston (5) with connecting rod (6), which is guided slidably in a guide tube (7) in order to interact with an opposing impact piston (8) via an intermediately generated compressible column of air.

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