Hand tool with handle

Abstract

The invention relates to a hand tool with a handle area and a method for its manufacture.

Description

[0001] The invention relates to a hand tool with a handle area and a method for its manufacture.

[0002] Hand tools with handles, and especially trowels such as finishing trowels, are already known. Existing hand tools have the disadvantage of being very heavy, primarily due to the use of metals like steel and aluminum. Finishing trowels typically consist of a blade, a base, a rib, and a handle, onto which a handle is usually screwed, pressed, or clamped. The base, rib, and handle are often referred to as the support.

[0003] WO2019167529A1 describes pliers whose parts may be partially made of carbon fiber reinforced epoxy resin. Wear parts such as the jaws are made of steel.

[0004] JP11006282A describes a concrete trowel with a long and wide base and a centrally located support neck. The trowel blade may contain carbon fibers.

[0005] TW418761U describes a one-piece hand tool in which the core is made of steel and this core may be covered with a material that is carbon or glass fiber reinforced. DE 93 10 980 U1 discloses a mortar board which is reinforced with carbon fiber.

[0006] Existing trowels have the disadvantage that the handle is connected to the blade via one or more necks in such a way that the force from the user's hand cannot be optimally transferred to the blade. The necks are typically located at the end of the handle and then connected directly to the blade at a near right angle. In these trowels, the handle, base, and shank, and especially the neck (the entire support structure), are often made of multiple pieces of metal, making them heavy and more complicated to manufacture.

[0007] Currently, trowels are often manufactured by joining one or two metal sheets to a metal support and a pressed-on plastic handle. The connection between the metal support and the intermediate sheet is often achieved by welding, using welding studs. The connection to the actual trowel blade is then often additionally made by gluing. Alternatively, the intermediate sheet can also be directly welded or glued.

[0008] The object of the present invention is to overcome the disadvantages of the prior art. In particular, it aims to achieve weight reduction while maintaining or improving performance, or to provide finger protection. Another objective is to shift the pressure point backwards to achieve better pressure distribution on the support.

[0009] The problem underlying the invention is solved by a hand tool according to claim 1.

[0010] The handle, and possibly also the support, made of such a material can replace, for example, a handle or support made of aluminum or steel. It has been found that the required range of carbon fiber content is optimal for obtaining a material that can match the mechanical properties of aluminum or steel in hand tools.

[0011] The handle preferably has a grip area (for example, the support) and possibly also a grip material, whereby the grip material can at least partially surround the grip area.

[0012] The hand tool preferably has no relatively moving parts.

[0013] The hand tool comprises a handle, a shank, a base, and a blade. Preferably, the handle or grip area is part of a support. The handle can therefore also be designed as the grip area of ​​a support. The support preferably comprises at least a base, a shank, and a handle area. A grip material can be arranged around the handle area to, for example, create the grip. The handle includes, for example, a grip area. The handle can also have a grip material in addition to the grip area, wherein the grip material is, for example, arranged at least partially around the grip area. The hand tool is a trowel, and in particular a smoothing trowel. The hand tool is preferably a trowel that comprises at least one blade and a support, wherein the support comprises a base, a shank, and a handle area.

[0014] The handle, as defined in the invention, can also be the grip area of ​​the support. The support, as defined in the invention, can have a foot area, a bridge area, and a grip area.

[0015] The grip area of ​​the handle or support can preferably be connected to a base area via a bridge area. The base area, in turn, can be connected to the blade of the trowel. Preferably, at least a part of the handle or grip area, a part of the bridge area, and a part of the base area are integrally connected. Preferably, the handle area, bridge area, and base area are formed in one or two pieces. According to the invention, the handle area, bridge area, and base area are formed in two pieces from two half-shells. These half-shells can be connected to each other, for example, by gluing, welding, clamping, and / or screwing. Particularly preferably, the two half-shells are screwed together. For this purpose, angled screw-on tabs can be provided, for example. The half-shells preferably have at least a partial case-like closure for connecting the half-shells.The two halves are preferably sealed watertight so that no water can penetrate the cavity inside the halves, for example, if the hand tool is left in water for an extended period. The seal can be achieved using the aforementioned case closure, or by gluing or sealing materials.

[0016] The combined weight of both half-shells preferably ranges from 100 to 300 grams. The weight of the support preferably ranges from 100 to 300 grams. The weight of the hand tool preferably ranges from 150 to 500 grams. Preferably, the half-shells are reinforced internally by ribs.

[0017] The hand tool is preferably assembled from several components in one piece. This allows, for example, the blade of a trowel to be made of a different material than the handle and / or grip area.

[0018] The handle and / or grip area preferably has a length in the range of 40 to 140% of the length of the foot area. Alternatively, the handle and / or grip area can have a length in the range of 30 to 90% of the blade length. The length of the handle and / or grip area is preferably in the range of 100 to 200 mm. The maximum width of the handle or grip area is preferably in the range of 20 to 80 mm, particularly in the range of 30 to 60 mm. Preferably, the handle has an exposed end. The handle and / or grip area can also have an end that is connected to the rib area (for example, integrally). The diameter of the handle and / or grip area preferably increases by at least 10%, particularly preferably by at least 20%, from the end connected to the rib area towards the exposed end.This prevents tools such as trowels from slipping out of the hand so easily.

[0019] By adapting the handle geometry, or rather the geometry of the grip area, a more ergonomic handling of the hand tool, such as the trowel, could be achieved. Application research revealed that many different movement sequences can be used in practice. Examples include "wiping" or flat pressing, which will be explained below.

[0020] When "wiping" or plastering, the handle or grip area is clamped between the palm and the metacarpal joint or base of the thumb. The aim of this process is to treat as large a wall surface as possible in one continuous motion. This is achieved by performing a radial wiping motion using shoulder and elbow movements. A firm grip on the trowel and a comfortable thumb resting area on the handle are crucial for performing this task comfortably for extended periods.

[0021] The bridge area and / or the handle area can be designed in such a way that a thumb rest is formed.

[0022] Applying a flat pressure to the wall with a hand tool, such as a trowel, is used for targeted compaction and visual refinishing of specific areas. Unlike "wiping," the quality of the movement is crucial here, not the quantity. The trowel handle is typically gripped loosely from above. The trowel blade is then guided parallel to the wall. With conventional handle designs, this requires bending the wrist, which, from an ergonomic perspective, represents a constant strain and can quickly lead to fatigue. Therefore, the diameter of the handle and / or grip area, as described above, preferably increases from the end connected to the rib.

[0023] Preferably, the center of gravity (by weight) of a hand tool, such as a trowel, lies within a range extending from the center along the longitudinal axis of + / - 10% of the tool's length. Preferably, a projection line runs vertically to the blade through the center of the foot and handle, or through the center of the foot and handle, extending along the longitudinal axis of + / - 20% of the tool's length. The advantage of these preferred embodiments is that the hand tool is well-balanced compared to prior art hand tools and is therefore easier to handle. If the hand tool is a trowel, such as a finishing trowel, materials like plaster can be smoothed much more easily than with prior art trowels.

[0024] The pressure point, as defined by the invention, is the point or area where the force of the user's hand is transferred to the tool. This is typically the grip area.

[0025] The handle or handle area is preferably at least partially surrounded by a handle material. The handle material is preferably an elastic material. For example, the handle material can be TPE (thermoplastic elastomer), leather, silicone, or any combination of these materials (e.g., TPE with leather). Holes filled with the handle material can be arranged in the handle area and / or in the half-shells. The handle material preferably has a larger diameter behind the holes than the respective hole diameter. The handle material can also enclose at least parts of the shank area. At least one rib (e.g., one on each side of the handle area) can also be arranged on the handle area. This has the advantage that the enclosing or injection-molded handle material cannot twist. It is particularly preferred that the inside of the shank area is at least partially enclosed by handle material.This serves to protect the fingers, especially the index finger, which is often inflamed with state-of-the-art trowels due to the lack of protection.

[0026] The handle or handle area preferably has an end cap at its exposed end, for example for striking.

[0027] Preferably, the hand tool has only one handle and / or grip area (and not multiple handles such as pliers).

[0028] The handle or grip area can be connected to a foot area via a bridge area. The bridge area preferably has an average circumference of 30 to 130 mm. The bridge area preferably has a length in the range of 30 to 100 mm. The bridge area preferably extends from one end of the handle to the foot area. The bridge area is connected to the foot area in a region of +15% to -15% of the midpoint of the foot area's length. Viewed from the side, the area of ​​connection between the foot area and the bridge area lies below the handle or grip area and is preferably at least 10% of the length of the handle or grip area from the outermost extension of the handle or grip area in the longitudinal direction of the handle or grip area.

[0029] The foot section preferably has a length in the range of 100 to 500 mm, particularly in the range of 120 to 360 mm. The foot section preferably has a width in the range of 20 to 100 mm, most preferably in the range of 30 to 60 mm.

[0030] The foot area can have an open structure, in particular a ribbed or honeycomb structure, on its side facing the blade. This effectively prevents warping of the foot area during injection molding.

[0031] Alternatively, the foot section can be shorter for certain applications (e.g., polished plaster / Venetian trowels) and may, for example, have a length in the range of 40 to 200 mm.

[0032] The base or the half-shells on one side and the blade on the other are preferably bonded together, in particular with a liquid adhesive. This has the advantage that screws or weld studs, as in the prior art, can be dispensed with. An adhesive layer (for example, a liquid adhesive made of acrylic material or polyurethane-based) or an adhesive tape (for example, a double-sided acrylic adhesive tape) is preferably arranged between the base and the blade. The adhesive layer is preferably flexible. The adhesive of the adhesive layer is preferably a one-component adhesive. The adhesive is preferably a polyurethane-based adhesive. Preferably, the blade is bonded to the base or the half-shells in a floating manner. Preferably, no intermediate sheet is arranged between the base and the blade.The adhesive layer or tape preferably has a thickness in the range of 0.1 to 5 mm, and most preferably a thickness in the range of 0.5 to 2 mm. Alternatively, the base or the half-shells on the one hand and the sheet on the other hand can also be welded together.

[0033] The foot section preferably has a distance of 0 to 0.5 mm from the blade at its longitudinal edges. The foot section preferably has a distance of 0.5 to less than 3 mm from the blade along its longitudinal centerline. The thickness of the foot section, in the outermost 10% of its length, averages no more than 70% of its thickness in the center. This allows the force from the handle, or handle and bridge area, to be distributed even more evenly across the entire foot section.

[0034] The width of the sheet is preferably in the range of 8 to 50 cm, and most preferably in the range of 10 to 30 cm. The length of the sheet is preferably in the range of 15 to 80 cm, and most preferably in the range of 20 to 50 cm. The thickness of the sheet is preferably in the range of 0.2 to 2 mm. The sheet is preferably made in one piece and, in particular, is not composed of different parts.

[0035] According to the invention, the handle or handle area contains 20 to 40 wt.% carbon fibers. The handle or handle area may preferably also contain 50 to 90 wt.% plastic, particularly preferably 60 to 80 wt.% plastic. The handle or handle area may also contain, for example, 1 to 15 wt.% metal (e.g., through screws). The low metal content ensures that the user of the hand tool can grip the handle or handle area even if the hand tool accidentally comes into contact with hot objects, due to the low thermal conductivity resulting from the low metal content. Preferably, the handle or handle area is made of a different material than the blade.

[0036] Preferably, over 50 wt.% of the material of the handle or handle area is located in the outermost 5 mm measured from the outer surface of the handle. The support is preferably at least partially hollow on the inside. Particularly preferably, the cavity within the support comprises 20 to 90 vol.%.

[0037] According to the invention, the web area contains 20 to 40 wt.% carbon fibers. The web area can preferably also contain 50 to 90 wt.% plastic, particularly preferably 60 to 80 wt.% plastic. The web area can also contain, for example, 1 to 15 wt.% metal (e.g., by means of screws). Preferably, the web area consists of a different material than the blade.

[0038] According to the invention, the base contains 20 to 40 wt.% carbon fibers. The base can preferably also contain 50 to 90 wt.% plastic, particularly preferably 60 to 80 wt.% plastic. The base can also contain, for example, 1 to 15 wt.% metal (e.g., by means of screws). Preferably, the base is made of a different material than the blade.

[0039] Preferably, one half-shell contains 20 to 40 wt.% carbon fibers. A half-shell may also preferably contain 50 to 90 wt.% plastic, particularly preferably 60 to 80 wt.% plastic. A half-shell may also contain, for example, 1 to 15 wt.% metal (e.g., through screws). A second half-shell preferably has a composition of the same preferred composition.

[0040] Preferably, more than 50 wt.% of the material of the two half-shells assembled to form the handle, bridge area and foot area is arranged in the outermost 5 mm measured from the outer surface of the assembled half-shells.

[0041] Preferably, the support contains 20 to 40 wt.% carbon fibers. The support may also preferably contain 50 to 90 wt.% plastic, particularly preferably 60 to 80 wt.% plastic. The support may also contain, for example, 1 to 15 wt.% metal (e.g., through screws). Preferably, the support is made of a different material than the blade.

[0042] The plastic is preferably selected from polyvinyl chloride, polypropylene, polyethylene, thermoplastic elastomers (TPE), polyamide, and combinations, mixtures, and copolymers thereof. The plastic is particularly preferably a polyamide. Preferably, the monomers of the polyamide together have between 5 and 15 carbon atoms in the main chain. The polyamide can, for example, be composed of one monomer or of two or three different monomers.

[0043] Preferably, the melting temperature of the handle material and / or the plastic is in the range of 150 to 350 °C, particularly preferably in the range of 210 to 300 °C. This ensures that the hand tool is not damaged even by brief contact with hot objects on a construction site.

[0044] Preferably, the tensile modulus of the handle material and / or the plastic is in the range of 10,000 to 30,000 MPa. The tensile modulus can be measured according to ISO 527 at 1 mm / minute. This ensures that the handle can withstand even high mechanical stress.

[0045] The elongation at break of the handle material and / or the plastic is preferably in the range of 1 to 5%. The elongation at break can be measured, for example, according to ISO 527.

[0046] The handle or handle area, the bridge area, the foot area and / or the half shells are preferably made of injection molding.

[0047] The blade is preferably made of metal or plastic, most preferably of steel. The plastic can correspond to the preferred embodiments of the handle area.

[0048] In a further embodiment, the object of the present invention is solved by a method for manufacturing the hand tool according to the invention, characterized in that at least the handle or handle area is formed from two injection-molded half-shells, these two half-shells are joined to each other in a force-fit manner and then connected to a metal part of the hand tool.

[0049] Preferably, the hand tool is a trowel. Preferably, the metal part is a blade of a trowel. Preferably, the handle or handle area, the shank area, and the foot area are formed from the two injection-molded half-shells.

[0050] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show: Fig. 1 shows the hand tool according to the invention. Fig. 2 shows the side view of a half-shell.

[0051] The following description of the figures includes specific examples relating to preferred embodiments and is not intended to infringe the scope of protection of the invention. Individual features or combinations thereof described below may serve to distinguish the invention from the prior art.

[0052] Fig. 1 Figure 1 shows an example of a trowel 10 as a hand tool according to the invention. A handle 12 is formed with a rib 14 and a foot 16 from two half-shells 18a and 18b. Thus, half of the handle 12, the rib 14, and the foot 16 are each integrally joined together in the form of a half-shell 18a and 18b. The foot 16 is bonded to the blade 20. The half-shells 18a and 18b can be screwed together.

[0053] Fig. 2Figure 18a shows an example of a half-shell 18a. The part of the half-shell 18a that forms half of the handle 12 is visible. The part of the half-shell 18a that forms half of the bridge area 14 is visible. And the part of the half-shell 18a that forms half of the foot area 16 is visible. The projection line 22 runs vertically to the sheet near the center of the foot area and near the center of the handle area.

[0054] In this example, the handle area 12, the bridge area 14 and the foot area 16 together form the support in accordance with the invention.

[0055] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list

[0056] 10 Hand tool 12 Handle 14 Bridge area 16 Foot area 18a, 18b Half-shells 20 Blade 22 Projection line

Claims

1. A hand tool with a handle portion, wherein the handle portion mainly consists of a carbon fiber reinforced plastic containing from 20 to 40 wt% of carbon fibers, wherein the hand tool is a trowel comprising at least a handle portion, a web portion, a base portion and a blade, and the handle portion, the web portion and the base portion are formed from two half-shells, and the web portion contains from 20 to 40 wt% of carbon fibers, and the base portion contains from 20 to 40 wt% of carbon fibers.

2. The hand tool according to claim 1, characterized in that the plastic is a polyamide.

3. The hand tool according to any one of the preceding claims, characterized in that the handle portion contains from 1 to 15 wt% of metal.

4. The hand tool according to any one of the preceding claims, characterized in that at least one rib is also arranged on the handle portion.

5. The hand tool according to any one of claims 1 to 4, characterized in that the web portion has an average circumference from 30 to 120 mm.

6. The hand tool according to any one of claims 1 to 5, characterized in that a projection line perpendicular to the blade extends through the center of the base portion and the center of the handle portion in the longitudinal direction + / -10% of the length of the hand tool, respectively.

7. The hand tool according to any one of claims 1 to 6, characterized in that the base portion and / or the half-shells are bonded to the blade with a liquid adhesive.

8. The hand tool according to any one of claims 1 to 7, characterized in that the base portion has a length in a range from 100 to 500 mm.

9. The hand tool according to any one of claims 1 to 8, characterized in that the combined weight of both half-shells is in a range from 100 to 300 grams.

10. The hand tool according to any one of claims 1 to 9, characterized in that the handle or the handle portion is at least partially covered by a handle material.

11. The hand tool according to claim 10, characterized in that holes filled with the handle material are arranged in the handle portion and / or the half-shells.

12. The hand tool according to any one of claims 1 to 11, characterized in that the base portion has an open structure, in particular a rib or a honeycomb structure, on its side facing the blade.

13. A method for manufacturing the hand tool according to any one of claims 1 to 12, characterized in that at least the handle portion is formed from two injection-molded half-shells, these two half-shells are non-positively connected with each other and then connected to a metal part of the hand tool.

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