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US 2003/0196527 A1Published application
Hand tool, in particular, a screwdriver
AssigneeWera Werk Hermann Werner GmbH & Co.
InventorMartin Strauch
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AssigneeWera Werk Hermann Werner GmbH & Co.
InventorMartin Strauch
Estimating the term…
The invention relates to a hand tool, in particular in the form of a screwdriver or a file, comprising one or more working surfaces with a grooved profile. According to the invention, the grooves are formed by recesses which are created using high-energy irradiation and which have border ribs. The border ribs can be formed by the edges of a fusion which immediately solidifies into a dish-shaped structure.
A hand tool, in particular a screwing tool or a wrench, as well as pliers, a clamping tool or a file, having one or more recess-profiled working faces, characterized by recesses which are produced by means of high-energy irradiation and have edge ribs.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the edge ribs (10) which lie opposite one another are the edges of a melt which has immediately solidified to form a well-like structure.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the well-like structure is approximately 50 μm thick.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the well-like structure is harder than the region of the working surface which surrounds it, and in particular has a hardness of greater than 62 HRC, preferably 64 to 66 HRC.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized by a tempered zone of softer material which lies below the well-like structure and the hardness of which rises as the depth increases until it reaches the hardness of the base material, preferably from 50 HRC to 60 HRC.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the tempered zone is approx. 30 μm thick.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the profiling is applied to a metal coating (5).
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the metal coating is a chromium layer or nickel or nickel-phosphorus layer applied by electrodeposition.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized by hard-material particles (7) (diamonds), in particular diamond chips, which are introduced in the metal layer (5).
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the recesses form a roughness which is produced through partial evaporation and transformation of material.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized by recesses in the form of a multiplicity of channels (9) which in particular run next to one another and have embankment-like edges (10).
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized by channels which cross one another.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that profile lines which are formed by the embankment-delimited recesses, over virtually their entire linear width, have a surface hardness which is approximately twice as great as the unprofiled region of the engagement surface (8).
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the recesses are crater-shaped individual recesses.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the working face (8) is the working tip (3) of a blade (2) of a screwing tool.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized by a surface which adjoins the working tip of a screwdriver, is formed in particular as a flat face and is provided with profile strips.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the flat face is the flattened section of a slotted screwdriver which is close to the tip.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the flat face is a polygonal face of a polygonal blade (2).
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the hand tool is a file.
The hand tool according to one or more of the preceding claims or in particular according thereto, characterized in that the hand tool is a hollow file, in particular with a longitudinal narrow face (15) disposed in the apex of the cavity.
A process for profiling working faces on tools in particular according to one or more of the preceding claims, characterized in that the working face (8) is briefly irradiated over a large area and/or locally with a high level of energy, such that the region of the irradiated zone which is close to the surface melts and solidifies at the edge to form a rib.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that the laser irradiation is carried out after hardening of the tool.
The process according to one or more of the preceding claims or in particular according thereto, characterized by a laser beam which is oriented at an acute angle onto the workpiece engagement surface.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that the workpiece engagement surface (8) is coated with metal before the laser treatment.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that the work piece engagement surface (8) is chrome-plated before the laser treatment.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that the energy is selected to be such that, when a focused laser beam passes over the metal surface, channels (9) comprising structureless martensite as a result of brief partial melting and/or evaporation of metal form, and in the edge region (10) these channels project above the adjacent, untreated surface in the manner of an embankment.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that diamonds (7) which are applied to the steel base body (4) are partially rounded during the application of the laser beam.
The process according to one or more of the preceding claims or in particular according thereto, characterized in that the laser power and the pass velocity of the laser are matched to one another in such a way that the waves which form in the melt and move toward the edge of the zone which is exposed to the energy solidify instantaneously just before they break.
Dependencies are inferred from the claim text.
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Characterised by material or shape of the tool bit: characterised by material used or surface finishing
Tools or bench devices not otherwise provided for, for fastening, connecting, disengaging
Term end not estimated
The invention relates to a hand tool, in particular a screwing tool and preferably a screwdriver or a wrench, and also pliers, a clamping tool or alternatively a file, having a recess profiled working face.
The invention also relates to a process for profiling working faces on tools of the type described above.
German utility model DE 95 00 780.2 U1 has disclosed a tool of the generic type. The utility model describes a screwdriver bit for crosshead screws, in which the working faces are profiled in linear form, with alternating recesses and elevations being formed. A channel profile with ribs flanking the channel is formed. During production of a screwdriver bit of this type, first of all the ribs are stamped. Then, the tool is hardened. The influences on the surface during hardening also act on the ribs. In the case of an excessively brittle tool, in which hard ribs project out of a hard base body, an excessive notch effect is produced. This can only be avoided by setting a lower surface hardness. However, this leads to relatively soft ribs which can then also rapidly become worn. In this context, one is faced with the problem that, on the one hand, a wear-resistant rib entails excessive brittleness of the tool, while, on the other hand, avoiding the brittleness of the tool as a whole leads to soft ribs, which therefore become worn.
Exemplary embodiments of the invention are explained below with reference to appended drawings, in which:
FIG. 1 shows a screwdriver with laser-profiled working tip,
FIG. 2 shows the working tip,
The exemplary embodiment illustrated in FIGS. 1 and 2 is a screwdriver having a handle and a blade 2. At its end, the blade 2 has a working tip 3. This working tip 3 forms a workpiece engagement surface 8. In the exemplary embodiment, the latter is in the form of a cross profile. Multiple, parallel passage of a laser beam over this workpiece engagement surface 8 produces a multiplicity of linear profile strips 6 running parallel to one another. The action of the metal coating 5 which has been applied to the steel core 4 strengthens the material. This strengthening of the material in the region of the material engagement profile 6 is associated with an increase in surface hardness of approximately 100%. The zone 6 to which energy is applied yields back slightly with respect to the zone surrounding it to which energy is not applied. The application of the laser beam results in the formation of a melt which follows the path of the laser beam. On account of the very high temperature gradient with respect to the bulk material, the melt is cooled very rapidly. The solidified channel then has a considerably greater hardness than the material surrounding the channel. The focused laser beam is preferably guided and oriented in such a way that the melt rises up in the manner of an embankment at its edges, in order in this way to produce annealed edge ribs. The material for this wave originates from the recess lying between the waves. The edge ribs are preferably formed by thermodynamically indexed flow movement in the melt, in such a manner that the material flows away from the center of the melt toward the edge, in order to solidify there.
The energy is applied using a focused laser beam. The laser beam source used may be a writing laser, in particular a diode laser, which is operated with a high power output. In the exemplary embodiment illustrated in FIG. 3, the steel core 4 bears a metal coating 5, which may be nickel phosphide. The laser beam which is guided with a writing action over the surface effects local, partial melting not only of the layer 5 but also of the adjoining zone of the steel base body 4. Then, the melt is suddenly solidified. In the process, an elongate crater is formed in the shape of a channel 9 with two embankment-like edges 10 which project above the surface of the metal coating 5. This leads to roughening of the surface, the material which has partially melted and suddenly cooled having a higher hardness. This material is structureless martensite.
In the exemplary embodiment illustrated in FIG. 4, diamond chips 7 are additionally introduced into the nickel coating 5 and in regions project above the surface of the coating. The local heating by means of focused laser beam here too forms a linear profile strip 6. This profile strip 6 forms a channel 9 with edge-side waves 10 which project above the surface. During the local application of energy, not only is the metallic material partially melted, but also it is evaporated. The diamond chips to which energy is applied in the process in regions undergo a phase transformation. They may be oxidized at the edge in such a manner that they acquire a rounded structure. The diamond chips 7′ which lie in the region of the profile strip 6 then no longer project above the surface.