EP0174532A2 - Attachment of a wooden handle - Google Patents

Abstract

When attaching a wooden handle (11) to a plastic sleeve (12) for receiving a coupling nipple, it is proposed to join the plastic sleeve (12) directly as an injection moulded part to the outside of an axial end region (13) of the wooden handle (11). The end region (13) can have annular grooves (16, 17). For the purpose of strengthening, the handle attachment can be surrounded by a tubular piece (14). The method for producing this handle attachment provides for inserting the handle (11) with its end region (13) into a form tool and introducing, in particular injecting, the plastic sleeve (12) into the intermediate space between the form tool and the end region (13) of the wooden handle (11). <IMAGE>

Description

The invention relates to a fastening of a plastic sleeve or the like, a longitudinal opening for receiving a coupling nipple. and has a transverse threaded hole for receiving a screw on a wooden handle.

It is already known (DE-PS 2617622). to attach a garden tool provided with a coupling nipple, insert a plastic sleeve into a pipe section and push the pipe section at its opposite end onto a wooden handle.

To improve the attachment between a tube sleeve and a wooden handle, it is known (DE-PS 2639016) to use a connecting element in the form of an approximately U-shaped strip of flat material between the tube and the handle.

Both mounting options have proven themselves. However, they require the production and preparation of a relatively large number of individual parts.

The invention has for its object to provide a handle attachment that is easier to manufacture, in which the connection properties are improved, the number of parts and thus the manufacturing and storage costs are reduced and which is better sealed against water ingress.

To achieve this object, it is provided according to the invention that the plastic sleeve has a section formed integrally with it, which is arranged around an axial end region of the wooden handle and is directly connected to it. As a result, only a single component is required in addition to the wooden handle, which is attached directly to the wooden handle. The plastic can be a thermoplastic, but reaction resins are also possible, which can be glued or foamed around the end area. It has been found that the connection of the plastic with the wood is extremely good, since the wood has a relatively rough fiber-rich surface, so that there is a good connection with the plastic Wooden handle is sprayed.

In a further development it can be provided that the end region of the stem has a reduced diameter. In this case it is possible that the overmolded plastic region runs flush with the rest of the stem, so that there are no edges in which dirt or moisture can become lodged. The reduced diameter of the handle can be achieved by simple milling, which also has the advantage that the surface is relatively rough. This in turn leads to improved adhesion between the plastic and the wood.

The invention provides that the length of the end region of the stem or the overmolded section of the plastic sleeve is at least about twice as long, preferably three times as long as the diameter of the stem. This leads to a mechanically good connection, since the adhesion surface is sufficiently large.

To further improve the durability of the fastening, it can be provided that the plastic sleeve is preferably injected into a tube which surrounds the end region of the stem and projects beyond the stem land and into the space between the tube and the stem. This leads to increased mechanical stability. The tube can advantageously consist of metal, in particular aluminum, but it can also consist of a possibly differently composed plastic. The tube increases the bending moments to be transmitted and holds the plastic sleeve firmly clamped.

It can also be provided here that the outer diameter of the tube corresponds at least in the region overlapping the stem to approximately the same as the outer diameter of the stem in its remaining region. This creates a smooth transition between the outside of the tube and the adjoining area of the stem, so that no dirt can accumulate.

In a further development it can be provided that the handle has at least one ring groove in its end region. With the aid of this ring groove, which is filled with the plastic, an increase in the tensile strength is achieved. Two such ring grooves are expediently provided.

In a further development it can be provided that the tube has a reduced diameter in its area projecting above the stem. In this tube area, in which the stem does not engage, the longitudinal opening for receiving a coupling nipple is arranged. The reduction in the drilling diameter can be produced by the known method of pulling in a pipe, for example an aluminum pipe. The reduced diameter makes it possible, among other things, to only have to make the tube as thick in this area as is necessary for the insertion of the coupling nipple, whereby wooden handles of different thicknesses can be used.

In order to improve the anti-rotation device around an axis running in the longitudinal direction of the fastening, the invention proposes that the tube is ribbed on the inside in its region overlapping the handle. While the plastic adheres sufficiently firmly to the fibrous surface of the wood, the internal ribbing of the tube ensures particularly good adhesion of the tube to the plastic in the direction of rotation. The ribbing also increases the interface between the pipe and the plastic. A particularly favorable type of ribbing is provided if the tube has longitudinal grooves formed from the outside in this area, which form corresponding ribs on the inside of the tube. So grooves are formed in the outside of the tube, which push through on the inside. The material thickness of the tube remains the same everywhere, so that the corresponding webs are formed on the inside without the material being weakened. The installation of the grooves from the outside naturally has manufacturing advantages.

The invention further provides that the tube has an opening of enlarged diameter in the area of the threaded bore of the plastic sleeve, an attachment penetrating the opening to the outside being formed on the plastic sleeve. Thereby, for example, can be the length of the thread, in which the Feststellsch- ₃ is arranged ube, enlarge. This leads to better guidance of the screw and a longer service life. In addition, of course, this also leads to securing the connection between the plastic and the pipe. During production, the molding tool can have a corresponding shape at this point. The approach can advantageously be used to have a device which interacts with the screw and by means of which the screw is held captively. For example the approach can have a snap-on collar and, if applicable, radial slots which enable the snap-on collar to be deformed more easily. Such a captive device is known from DE-GBM 7916056.

The invention also proposes a method for producing a handle attachment, in which a plastic sleeve is connected to a wooden handle. This handle attachment can be designed as described above.

According to the invention, the stem is inserted with its axial end region into a mold and then plastic is introduced into the space between the mold and the end region of the stem. The plastic can, if it is a thermoplastic, for example, be injected, but it can also be introduced and cured in some other way, or can also be foamed.

It is particularly favorable if the plastic is injected.

The axial end region of the stem can be selected depending on the requirements, it being sensible that its length is at least about two to three times the diameter of the stem.

For better axial locking between the plastic and the handle, it can be provided that at least one, preferably two, ring grooves are milled or screwed into the end region of the handle before the handle is inserted.

In order to ensure a smooth transition between the outside of the plastic sleeve and the outside of the handle, it can be provided that the end region of the handle is brought to a reduced diameter, in particular milled, before it is inserted into the mold. It may be possible, for example, to make the region of reduced diameter slightly conical, the diameter increasing in the direction of the end of the stem. Good locking between wood and plastic can also be achieved with this.

In a further development it can be provided that a tube is inserted into the mold in such a way that it surrounds the end region of the handle and projects beyond its end, and that the plastic is introduced into the space between the tool and the end region of the handle. This further improves the resulting connection, since the plastic sleeve is surrounded on the outside by the tube.

In the transition area between the end of the tube and the handle of the wood, the tool can be pressed onto the wooden handle according to the invention, wherein the pressing can take place up to the inside diameter of the tube. In this way it is achieved that the plastic does not emerge from the corresponding end of the tube and is therefore invisible from the outside.

However, as is also proposed by the invention, it is also possible to form a plastic collar in the transition region between the tube and the stem. In this case, the molding tool can be designed so that it does not protrude inward beyond the outer diameter of the tube.

In a further development it can be provided that a molding tool with at least one cavity is used in the region of the federal government. The cavity can be connected to the collar area via a narrow opening, so that balls or the like after completion of the handle attachment in the area of the collar. are formed, which are connected to the federal government via narrow webs. These narrow webs can be broken off immediately so that the spherical projections can be removed. This training has the advantage that it can be checked at a glance whether the spraying process has been carried out without errors.

It is particularly expedient if a tool with a small radial distance is used in the region of the end of the tube. The plastic is introduced under pressure, so that under its pressure the tube can easily deform outwards due to the small radial distance of, for example, 0.2 mm. This deformation must still be in the elastic range of the pipe material used. When the plastic hardens, a certain amount of shrinkage can occur, but due to the elastic deformation of the pipe material it is absorbed by its reshaping, so that no loosening or the like occurs after hardening.

The invention further provides that, when the plastic sleeve is produced, a threaded attachment which penetrates a lateral opening of the tube is formed, in particular shaped. For this purpose, the plastic sleeve is positioned in the tool so that its opening conforms to the shape on the outside of the tube.

The invention further provides for the tube to be tapered in its area projecting over the stem before it is inserted into the mold. This can be done by the known pulling in of pipes. Furthermore, it can be provided that the tube is provided with grooves before it is inserted into the mold. These grooves on the outside form similarly shaped grooves on the inside of the tube, which, when they run in the longitudinal direction, bring about a particularly favorable rotation lock between the tube and the plastic introduced.

To produce the grooves, it can be provided that a ring with embedded balls is placed over the tube and moved along the tube. Depending on the diameter of the circle inscribed in the balls, a more or less deep groove is formed by each ball, which can be designed to run obliquely both in the pure longitudinal direction and when the ring rotates during the movement. This way of producing the grooves has the advantage that if a ball wears out, it can easily be replaced.

• Fig. 1 einen Längsschnitt durch eine Stielbefestigung nach der Erfindung;
• Fig. 2 eine Aufsicht auf die Anordnung in Fig. ₁;
• Fig. 3 eine Ansicht der Anordnung von links in Fig. ₁;
• Fig. ₄ einen Schnitt längs Linie IV-IV in Fig. 1;
• Fig. 5 einen Schnitt längs Linie V-V in Fig. 1;
• Fig. 6 schematisch die Anordnung bei der Herstellung einer Stielbefestigung;
• Fig. 7 eine der Fig. 6 entsprechende schematische Ansicht bei einer anderen Herstellungsart;
• Fig. 8 eine nochmals geänderte Herstellungsart.

Further features, details and advantages of the invention result from the claims, the following description of preferred embodiments of the invention and with reference to the drawing. Here show:

• 1 shows a longitudinal section through a handle attachment according to the invention.
• Fig. 2 is a plan view of the arrangement in Fig. ₁ ;
• Fig. 3 is a view of the arrangement from the left in Fig. ₁ ;
• Fig. _{4 is} a section along line IV-IV in Fig. 1;
• 5 shows a section along line VV in Fig. 1.
• Fig. 6 shows schematically the arrangement in the manufacture of a handle attachment;
• FIG. 7 shows a schematic view corresponding to FIG. 6 in another type of manufacture;
• Fig. 8 shows another change in production.

Fig. 1 shows in longitudinal section an attachment between a wooden handle 11, a plastic sleeve 12 and a tube 14 extending over one end region 13 and the plastic sleeve 12, which in the present example consists of aluminum. The length of the end region 13 of the wooden handle 11 is approximately three times as long as the diameter of the wooden handle 11. The end region 13 itself has a reduced diameter, the free end 15 of the end region 13 being slightly frustoconical. In this area, the end area 13 contains a umlau fende annular groove 16, which is approximately trapezoidal in cross section. A second such groove 17 is arranged closer to the end of the tube 14. It also has an approximately trapezoidal cross section.

The plastic sleeve 12 is injected into the interior of the tube 14, it having a first section 18 on the left in FIG. 1, in which it contains a longitudinal opening 19. The longitudinal opening 19 has a circular cross section towards the end 20 of the plastic sleeve 12, while individual webs 21 running in the longitudinal direction extend further inside. The longitudinal webs form contact surfaces for a coupling nipple to be inserted into the longitudinal opening 19.

Beyond the area 18 of the plastic sleeve 12, this forms a second section 22 which is arranged in one piece in the space between the end area 13 of the wooden handle 11 and the tube 14. The plastic material extends in this area into the ring grooves 16 and 17 and connects due to the fibrous structure of the wood shaft 11 with its end area 13, so that an absolutely secure connection is created.

In the transition area 23 between the tube 14 and the wooden handle 11, the plastic of the section 22 of the sleeve 12 forms a circumferential collar 24, which forms a smooth transition between the tube 14 and the wooden handle 11. At the opposite end of the tube 14, a collar 25 is also formed from the material of the plastic sleeve 12, which closes the handle attachment to its free end.

At the top in FIG. 1, the tube 14 contains an opening 26 through which an extension 27 of the plastic sleeve 12 passes. The approach 27 contains a longitudinal bore 28 which extends transversely to the longitudinal opening 19 of the plastic sleeve 12. In its area closest to the longitudinal axis of the tube ₁₄ , the longitudinal bore 28 contains a thread 29. On the outside, the attachment 27 contains an overlap 30, which projects somewhat outwards from the otherwise cylindrical outside of the attachment 27. In this area, the attachment contains 27 a total of four slots 31, the side walls 32 of which run approximately radially, see also FIG. 2.

₁ and 2 show that the tube 14 has an enlarged diameter in the stem area and a smaller diameter in the area projecting over the stem 11. In both areas, the tube 14 is cylindrical.

In the area of enlarged diameter, the tube, see FIG. 2, contains a plurality of grooves 33 running in the longitudinal direction, the boundary surfaces of which lie on an arc of a circle when viewed in cross section. The grooves 33 are produced by bending the tube 14 so that they are also present on the inside of the tube 1 ₄ in the end region 13 of the stem 11.

Fig. 3 shows the view of the handle attachment from the left in Fig. 1 and 3. The tube 14 is not visible from the left, since the front is formed by the collar 25. The webs 21 already mentioned in FIG. 1 form inwardly directed contact surfaces 34, on which adjacent surfaces of a hexagon can rest. At its end, the longitudinal opening 19 is penetrated by a transverse web 35 which limits the insertion of a hexagonal coupling nipple. It is then loaded transversely by a screw screwed through the shoulder 27 and the thread 29 and pressed against the contact surfaces 3 _{4 of} the longitudinal webs 21. This leads to a play-free mounting of a coupling nipple on the stem 11.

Fig. 4 shows the section along line IV-IV in Fig. ₁ , the section extending across the neck 27. The projection 27 protrudes somewhat on the inside of the longitudinal bore 19, while it clearly protrudes from the tube 14 on the outside. There are four slots 31 on the outside, which extend from the upper end of the extension 27 into the area just before the tube 14. Outside the tube 14, the shoulder 27 engages with a lip 36 around the outside of the opening 26 of the tube 14, so that it is also clearly defined here and prevents the ingress of liquid. The thread 29 is formed only in the lower region of the extension 27.

Fig. 5 shows a section through the tube 14 in the end region 13 of the wooden handle. On the outside, the tube contains a total of eight grooves 33 distributed uniformly over the circumference, which are delimited in cross section by a circular line. The grooves 33 correspond to the inside of the tube 14 corresponding part-circular ribs 3 _7, which extend up to the outer side of the end portion 13 of the stem wood. 11 Between the ribs 37, a total of eight approximately trapezoidal spaces extending in the longitudinal direction of the wooden handle 11 are created, into which the plastic can penetrate and reach the transition area 23 to form the collar 24. After the plastic has hardened or solidified, the tube 14 is therefore completely secured against rotation by means of the plastic on the end region 13 of the wooden handle 11. The grooves 33 on the outside, which are produced with the aid of balls which are moved in the longitudinal direction, also form recessed grips on the outside which favor the grip and handling of the handle from the outside.

6 shows the arrangement of the end region 13 of the stem 11 in a mold 38, which is only partially shown, in a highly schematic manner. The tube 14 already has the finished shape, ie with grooves 33 on its outside. There is a small distance 39 between the molding tool and the outside of the tube 14, which allows the aluminum tube 14 to be deformed outwards when the plastic is injected under pressure. The molding tool 38 contains a step 40 which lies directly against the free end _{41 of} the tube 14 . The depth of the step 40 corresponds to the thickness of the tube 14. Behind the step 40, the molding tool contains a slightly bent section 42 which extends outwards. During injection of the plastic so the wooden handle 1 ₁ in this area is pressed downward so that the plastic material in the cavity 43 between the outside of the timber stem 11 and the inside of the tube can penetrate 14, but not beyond the free end 41 of the tube 14 can step out.

In the arrangement in FIG. 7, another tool 44 is used which does not have the step 40 shown in FIG. 6. The distance 39 can be seen again. The tool 4 ₄ runs in a straight line up to the area of the wooden handle 11 with an enlarged diameter, so that the plastic entering the cavity 43 beyond the free end 41 of the tube ₁₄ can form the collar 24 shown in FIGS. 1 and 2.

In the arrangement according to FIG. 8, the tool 45 contains an approximately spherical cavity 46 into which the plastic can enter from the cavity 43 and the collar 24 formed through a narrow opening 47. After the hardening and removal of the tool 45, a ball is formed on the collar 24 in the region of the cavity 46 and is connected to the collar 24 with the aid of a narrow web 47. If the ball at least in Area of the small opening 47 is present, this means that the plastic has actually completely penetrated into the cavity 43. The balls can then be broken off due to the small bars.

Claims (14)

1. Attachment of a plastic sleeve (12) having a longitudinal opening (19) for receiving a coupling nipple and a transverse threaded bore (29) for receiving a screw, on a wooden handle (11), characterized in that the plastic sleeve (12 ) has a section (22) formed in one piece with it, which is arranged around an axial end region (13) of the wooden handle (11) which may have a reduced diameter and is connected directly to the latter. 2. Fastening according to claim 1 or 2, characterized in that the length of the end region (13) of the stem (11) or the overmolded section (22) of the plastic sleeve (12) is at least twice as long, preferably at least three times as long as the diameter of the stem (11). 3. Fastening according to one of the preceding claims, characterized in that the plastic sleeve (12) in a the end region (13) of the stem (11) surrounding and over the stem end (15) projecting tube (14) and in the space between the tube (14) and the stem (11) is injected, the outer diameter of the tube (14) preferably corresponding at least in the area surrounding the stem (11) approximately equal to the outer diameter of the stem (11) in its remaining area. 4. Fastening according to one of the preceding claims, characterized in that the stem (11) in its end region (13) at least one annular groove (16, 17) and / or the tube ( ₁ 4) in its projecting over the stem (11) Area has a reduced diameter. 5. Fastening according to claim 3 or 4, characterized in that the tube (14) in its area around the stem (11) is ribbed inside, the ribbing in particular by in the tube (14) in its embracing the stem (11) Area formed from the outside longitudinal grooves (33) 6. Fastening according to one of claims 3 to 5, characterized in that the tube ( ₁₄ ) in the region of the threaded bore (29) of the plastic sleeve (12) has an opening (26) of enlarged diameter, and on the plastic sleeve (12) a Opening (26) outwardly penetrating projection (27) is formed. 7. A method for producing a handle attachment, in which a plastic sleeve (12) is connected to a wooden handle (1 ₁ ), characterized in that the handle (11) with an axial end region (13) in a mold (38, 4 ₄ , ₄ 5) and then plastic is introduced, in particular injected, into the space between the tool (38, ₄ 4, 45) and the handle end area (13). 8. The method according to claim 7, characterized in that before inserting the handle (11) in its end region (13) at least one annular groove (16, 17) milled or rotated and / or its end region (13) turned to a reduced diameter or is milled off. 9. The method according to claim 7 or 8, characterized in that in the mold (38, 44, 45), a tube (14) is inserted such that it surrounds the end region (13) of the stem (11) and over the end ( 15) protrudes, and that the plastic is introduced into the space between the tool (38, 44, 45) and the end region (13) of the handle (11). 10. The method according to claim 9, characterized in that in the transition region (23) between the tube (14) and stem (11) the wood is pressed by the tool (38) and / or between the tube (14) and stem (11) a plastic collar (24) is formed. 11. The method according to claim 9 or 10, characterized in that a molding tool (45) with at least one cavity (46) in the region of the collar (24) and / or with a small radial distance (39) in the region of the end of the tube (14 ) is used. 12. The method according to any one of claims 9 to 11, characterized in that when forming the plastic sleeve (12) a lateral opening (26) of the tube (14) penetrating threaded projection (27) is formed. 13. The method according to any one of claims 9 to 12, characterized in that the tube (14) is tapered before it is inserted into the mold (38, 44, 45) in its projecting over the stem (11). 14. The method according to any one of claims 9 to 13, characterized in that the tube (14) before it is inserted into the mold (38, 44, 45), preferably by being provided with grooves (33) that a ring with embedded Balls are moved over the tube (14) in the longitudinal direction.

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