WO2002076681A1

WO2002076681A1 - Plier- or clipper-like tool and method for application of grip sleeves made from plastic on the steel grip arms thereof

Info

Publication number: WO2002076681A1
Application number: PCT/DE2001/001196
Authority: WO
Inventors: Horst Holland-Letz
Original assignee: Felo-Werkzeugfabrik Holland-Letz Gmbh
Priority date: 2001-03-28
Filing date: 2001-03-28
Publication date: 2002-10-03
Also published as: EP1372915A1; DE10196217D2

Abstract

The invention relates to a plier- or clipper-like tool with grip sleeves (3) made from plastic directly moulded onto the steel grip arms (2). A sealing element (5b) is provided on the steel grip arm (2) for sealing thereof at the sealing point in the seal (8) of the injection mould (6), which may for example, comprise a zone forged on the steel grip handle (2), calibrated such as to fit exactly in a concave profile on the seal (8) without any gap. The seal element (5b) may be replaced by an elastic ring in an other embodiment, which compensates for tolerances between the grip arm and the concave profile of the seal.

Description

Pliers or scissors-like tool and method for applying plastic grip sleeves to its steel grip leg

The invention relates to a tool according to the preamble of claim 1 and a method according to the preamble of claim 7.

Plastic grip sleeves are usually injection molded separately from plastic for grip legs of pliers or the like and pressed onto the curved steel grip legs of the pliers. For this purpose, hard plastic handle sleeves are heated and pressed on in the semi-plastic state. In addition, the grip sleeves are often attached to the grip legs with adhesive. Handle sleeves made of elastic plastic are also used, which are cold-pressed onto the handle legs and fastened with adhesive.

The attachment of grip sleeves on the pliers legs in this way has several disadvantages. Pressing on the handle sleeves is not only an additional step, but also limits the design options of the handles. The wall thickness of the handle sleeves should be as equal as possible so that the sleeves heat up evenly and become evenly plastic in order to be able to adapt evenly to the curved handle legs. If the grip sleeves are ergonomically well designed, however, irregular shapes and wall thicknesses result, and grip sleeves of this type are difficult to pull onto the grip legs. It has therefore already become known to spray the handle sleeves directly onto the pliers legs (DE 297 05 522 Ul), similar to, for example, screwdrivers whose handles are are sprayed onto the blade shafts, which are, however, smooth and dimensionally tolerated here. In contrast, a problem with pliers or the like is that they are usually manufactured from drop-forged parts and are machined to a predetermined extent only in the area of the functional elements on the head and in the hinge, while the handle legs remain unprocessed. The handle legs therefore have relatively large dimensional tolerances, with the result that a good seal of the cross-sectional contours of the handle legs to the injection mold can generally not be achieved.

In contrast, the invention has for its object to develop the tools and methods of the types mentioned in such a way that regardless of the selected cross-sectional shape of the handle legs a good seal of the same is guaranteed in the sealing strip.

The features of claims 1 and 7 serve to solve these tasks.

The invention has the advantage that the handle legs are provided with a sealing element before the injection molding process where they come to rest in the sealing strip of the injection mold. This ensures on the one hand that the injection mold also closes securely in the area of the sealing strip. On the other hand, the handle legs need only be provided in a narrow area associated with the sealing strip with a sealing element adapted to the special sealing strip shape, so that the additional costs and procedural steps involved in production can be accepted.

The invention is explained below in connection with the accompanying drawings of exemplary embodiments. Show it:

Figure 1 is a partially sectioned plan view of a pair of pliers according to the invention.

Fig. 2 is a section along the line II-II of Fig. 1;

3 and 4 each a longitudinal section and a plan view of a sealing according to the invention elements for the pliers according to Fig. 1;

5 shows a top view, partly in section, of a partial piece of pliers corresponding to FIG. 1, but with a second exemplary embodiment according to the invention for a sealing element;

Fig. 6 is a section along the line VI-VI of Fig. 5;

7 and 8 each show a longitudinal section and a top view of a sealing element according to the invention of the pliers according to FIG. 5;

9 and 10 or 11 and 12 the views corresponding to FIGS. 1 and 2 of two further exemplary embodiments of a pair of pliers according to the invention;

13 shows a plan view of a pair of pliers according to the invention, inserted into an injection mold;

Fig. 14 is a section along the line XIV-XIV of Fig. 13;

FIG. 15 is a view corresponding to FIG. 5, but not cut, of a section of the pliers according to FIG. 13;

Fig. 16 is a section along the line XVI-XVI of Fig. 15;

FIGS. 17 to 19 or 20 to 22 views of the pliers according to FIG. 13 corresponding to FIGS. 14 to 16, but with different exemplary embodiments for the sealing element;

23 shows a partially sectioned top view of a pliers half inserted into an injection mold with a sealing element designed according to the invention as an injection molded part;

24 shows a section along the line XXIV-XXIV of FIG. 23;

25 and 26 each show a longitudinal section and a top view of the pliers according to FIG. 23 and 24 sealing element used;

27 to 29 or 30 to 32, FIGS. 24 to 26, corresponding views of two further sealing elements that can be used with the pliers according to FIG. 23;

33 and 34 the views corresponding to FIGS. 13 and 14 of a further embodiment of a pair of pliers according to the invention;

35 and 36 are views corresponding to FIGS. 25 and 26 of a sealing element used in the pliers according to FIGS. 33 and 34;

37 shows a view corresponding to FIG. 13 of sheet metal shears, the handle legs of which are provided with a sealing element according to a further exemplary embodiment of the invention; and

38 is an enlarged detail X of FIG. 37.

Fig. 1 to 4 show a pair of pliers with a pliers head 1, two handle legs 2 made of steel and two handle sleeves 3 made of plastic. According to the invention, a sealing element 4a is drawn onto the handle legs 2 at the ends of the grip sleeves 3 facing the pliers head. As will be explained in more detail below, these sealing elements 4a are each arranged where a sealing strip of the injection mold comes to rest when the grip sleeves 3 are produced by injection molding. In the exemplary embodiment, the sealing elements 4a, as shown in FIGS. 3 and 4, are designed as cylindrical rings which, for. B. are cut out of an elastic, tubular plastic material with a round internal and external cross section. After being pulled onto the handle legs 2, the sealing elements 4a essentially assume a cross-sectional shape (FIG. 2) which corresponds to that of the handle legs 2.

According to FIGS. 5 to 8, sealing elements 4b, on the other hand, consist of rings designed in the manner of round cord rings with a round cross-sectional profile, as shown in particular in FIG. 7. The remaining arrangement corresponds to that according to FIGS. 1 to 4. The sealing elements 4b expediently consist of an elastic plastic. In the exemplary embodiment according to FIGS. 9 and 10, the handle legs 2, which are generally produced by drop forging, each have a forged zone where the sealing elements 4a, 4b are in FIGS. 1 to 8, which, in the manner of a collar or bead, radially outwards protrudes. This zone is calibrated in a subsequent pressing process so that it can be inserted without a gap in the concave profile of the sealing strip of the injection mold and thus becomes a sealing element 5a or 5b, which corresponds to the sealing element 4a or 4b according to FIGS. 1 to 8 , 9 to 12 each show a pliers head 1, two handle legs 2 made of steel, and one each made of plastic by means of an injection-molded handle sleeve 3, the sealing element 5a having a round and the sealing element 5b having a hexagonal outer cross section ,

The sealing elements 4a, 4b are also preferably made of a plastic whose melting temperature is selected higher than that of the plastic used for the grip sleeves 3, so that the sealing elements 4a, 4b are not softened by the liquid plastic compound when the grip sleeves 3 are sprayed so that they lose their sealing effect. Furthermore, an elastic plastic quality is selected so that the sealing elements produced therefrom can expand when they are pulled onto the handle legs 2, but nevertheless remain firmly attached to the handle legs 2 at the location provided for their placement.

13 to 16 show a pair of pliers according to FIGS. 11 and 12 with sealing elements 5b calibrated by pressing, which have a hexagonal cross section on the outside. The pliers are inserted into an injection mold 6 which has two mold halves which, in the closed state, adjoin one another along a parting plane 6a which is only visible in FIG. 14 and perpendicular thereto, ie in the direction of a double arrow y for closing or opening the injection molds 6. and can be moved. Each half of the film has two cavities which face each other in the closed state of the mold 6 and each delimit a hollow 7 which has an outer contour which corresponds to the shape and size of the grip sleeves 3 to be molded onto the grip legs 2 (FIG. 11). To simplify the illustration, the injection mold in FIG. 13 is assumed to consist of a transparent material in order to make the relative position of the different parts visible. The injection mold 6 has on its end facing the pliers head 1 a narrow sealing strip 8 which, like the mold 6 itself, consists of two parts 8a, 8b (FIG. 14) which adjoin one another along the parting plane 6a in the closed state of the mold 6. In the closed state of the mold 6, the sealing strip 8 delimits two cavities 9 which accommodate the parts of the grip arms 2 which protrude from the mold 6 and whose walls, as shown in FIG. 14, are intended to seal against the grip arms 2 from the outside. Since both the sealing strips 8 and the handle legs 2, as explained at the beginning, have comparatively large manufacturing tolerances due to their manufacture by the drop forges or the like and therefore no optimal sealing is achieved when the injection mold 6 is closed, the sealing elements 5b serve the purpose according to the invention to compensate for existing dimensional tolerances between the handle legs 2 and the walls of the concave cavities of the sealing strip 8. The sealing strips 8 thus lie against the sealing elements 5b provided for this purpose, as a result of which the cavities 7 of the injection mold 6 are hermetically sealed on the top end face in FIG. 13 and the liquid plastic compound injected to form the grip sleeves 3 cannot escape to the outside ,

The sealing elements 4a, 4b and 5a according to FIGS. 1 to 10 serve the same purpose. For the sealing elements 5a, this is indicated in FIGS. 17 to 19, according to which cavities 9a in the sealing strip 8 are provided with semi-cylindrical wall sections adapted to the outer cross sections of the sealing elements 5a.

20 to 22 show an exemplary embodiment corresponding to FIGS. 17 to 19, with the difference that sealing elements 5c molded onto the handle legs 2 essentially have square or rectangular outer cross sections and cavities 9b of the associated ones

Sealing strip 8 have corresponding internal cross sections. 20 to 22, the same parts are provided with the same reference numerals as in FIGS. 13 to 19.

23 to 26, in which the same parts are also designated by the same reference numerals as in the preceding figures, show an embodiment of the invention analogous to FIGS. 1 to 4, with the difference that sealing elements 4d consist of individually produced plastic injection molded parts. This has the advantage that the inner and outer contours of the sealing elements 4c easily match the outer cross sections of the handle leg 2 or the inner cross sections of cavities 9d of the sealing strips 8 can be adjusted. 23 to 26, this is shown for square or rectangular inner and round outer cross sections of the sealing elements 4d. On the other hand, FIGS. 27 to 29 show correspondingly produced sealing elements 4e, each with substantially square inner and outer cross sections corresponding to the associated contours of the handle legs 2 or of cavities 9e in the sealing elements 8. Finally, FIGS. 30 to 32 show by injection molding Manufactured plastic sealing elements 4f, the inner cross sections of which are essentially square and the outer cross sections of which have a hexagonal shape, as also applies to the inner cross sections of cavities 9f of the sealing strip 8.

The exemplary embodiments according to FIGS. 1 to 32 relate to pliers with handle legs 2, which essentially consist of solid steel. There are also tool shapes, e.g. B. tin snips, which are provided in Fig. 33 to 36 with handle legs 2a, which consist of a U-shaped bent or folded sheet metal or the like, as shown in particular 34. For such gripping legs 2a, sealing elements 4g (FIGS. 35, 36) consisting of injection molded parts are preferably suitable, which consist of essentially solid plastic bodies which have U-shaped slots 10 which have shapes corresponding to the profile of the gripping legs 2a. As FIG. 34 shows, the outer contour of the sealing element 4g can, as in the previous exemplary embodiments, be adapted to the inner contour of cavities 9g formed in the sealing strip.

In the exemplary embodiments described so far, the sealing elements are designed as protruding elements in the form of beads or the like, which protrude radially above the handle legs 2. Alternatively, FIGS. 37 to 40 show an embodiment in which sealing elements 5d are provided which do not protrude in a raised manner, but are essentially flush with the rest of the surface of the grip legs 2 and can even be recessed behind them. These sealing elements 5d, like the sealing elements 5a to 5c (FIGS. 9 to 22), are preferably attached by a press-molding process carried out after forging the handle legs.

The invention is not restricted to the exemplary embodiments described, which are based on can be modified in many ways. This applies in particular to the outer or inner contours of the handle legs 2, 2a and the cavities 9 in the sealing strips 8, since the sealing elements are also particularly suitable for compensating for different contours of the handle legs 2 and cavities 9. Furthermore, when using the exemplary embodiments according to FIGS. 1 to 8 and 23 to 36, it may be advantageous to have the cavities 9 of the sealing strips 8 in the closing direction of the injection mold 6 (arrow y in FIG. 14) with a slight undersize and in a transverse direction with a slight oversize. This ensures that the sealing elements 4, which are elastic per se or are made of an elastic material, are somewhat compressed in the closing direction when the injection mold 6 is closed, and can accordingly dodge transversely thereto. As a result, tolerances are optimally compensated and particularly good sealing effects are achieved without the occurrence of disruptive burrs. Furthermore, the sealing elements other than the outer and / or inner contours shown can be given, in particular in such a way that the sealing elements can be easily inserted into the sealing strips 8 or removed from them again. Furthermore, it may be advantageous to manufacture the two halves 8a, 8b of the sealing strip 8 from separate individual parts which, for. B. with the help of screws 11 on the upper end faces of the associated halves of the injection mold 6. This makes it possible in particular to replace the sealing strips 8 if they should be damaged when the steel legs 2 are inserted or removed. It would also be conceivable to remove the sealing elements 4 from the steel legs 2 again after producing the grip sleeves 3, for. 1 in the case of the sealing elements 4a according to FIGS. 1 to 4), in particular if they are not at least partially sunk into the grip sleeves 3. Furthermore, the invention is not limited to pliers and scissors of the type described, but can also be used for other pliers and scissor-like tools which have legs to be encapsulated with plastic handles. Finally, it goes without saying that the various features can also be used in combinations other than those shown and described.

Claims

Expectations

1. pliers or scissor-like tool with steel handle legs (2) and directly sprayed on this grip sleeves (3) made of plastic, characterized in that the steel handle legs (2) at the point where they are sprayed in a sealing strip ( 8) of the injection mold (6), have a sealing element (4, 5).

2. Tool according spoke 1, characterized in that the sealing element (4) consists of an elastic ring.

3. Tool according spoke 2, characterized in that the sealing element (4a, 4b) is tubular or with a round cross-sectional profile.

4. Tool according to claim 2 or 3, characterized in that the sealing element (4d to 4g) consists of an injection molded part.

5. Tool according spoke 1, characterized in that the sealing element (5) from a to the steel handle leg (2) forged zone, which is recalibrated by pressing so that it fits without a gap in a cavity (9) of an associated Seal bar (8) fits.

6. Tool according spoke 5, characterized in that the sealing element (5a, 5b, 5c) has a round or non-circular outer cross section.

7. Method for applying handle sleeves (3) made of plastic to steel handle legs (2) of pliers-like or scissor-like tools, in which the handle legs (2) have an injection mold (6) with a sealing strip (8) with a concave profile (9). inserted and then directly provided with the gripping sleeves (3) by injection molding, characterized in that the gripping legs (2) are provided with a sealing element (4, 5) at the point to be located in the sealing strip (8) during injection molding and inserted into the sealing strip (8) with it.

8. The method according to claim 7, characterized in that the sealing element (4) is designed as an elastic ring.

9. The method according to claim 7, characterized in that the sealing element (5) as a zone with a round or non-circular cross-section forged onto the handle leg (2) and recalibrated by pressing so that it fits snugly into a cavity (9) of the Sealing strip (8) fits.