Felting needle, needle plate for a felting machine, and procedure for inserting a felting needle into a needle plate

Abstract

The felting needle of the invention has a shank attached to a rear end of the needle in its longitudinal direction. The felting needle has a working section attached to a front end. The shank has a clamping section and a guide section. The guide section is positioned further forward in the longitudinal direction than the clamping section. The diameter of the guide section, measured perpendicular to the longitudinal direction, is smaller than the diameter of the clamping section, also measured perpendicular to the longitudinal direction. The felting needle of the invention is characterized in that the diameter of the guide section is at most 12%, preferably at most 9%, and even better at most 6% smaller than the clamping diameter. This allows the felting needle to be inserted more easily into the needle board and protects the board during insertion.

Description

[0001] The present invention relates to a felting needle. Felting needles are known, for example, as notched needles for compacting nonwovens or as forked needles for structuring nonwovens. Felting needles are generally elongated steel parts which, when used, have a working section arranged longitudinally at their front end to treat nonwovens and are held by a shaft at their rear end in a needle board or a comparable device of a felting machine. Through-holes are provided in the so-called needle board for holding the felting needles, into which the felting needles are inserted. The shaft of the felting needle is generally cylindrical and has a diameter such that the shaft of the felting needle is held under tension and clamped in the bore of the needle board. The tension is so strong that the felting needle cannot usually be inserted into the bore by hand, but only with the aid of a tool.The tool used is often a hammer or similar implement to drive the felting needle into the needle board. Additionally, the needle often has a foot at one end, angled at approximately 90° to its longitudinal axis and used to position it lengthwise relative to the needle board. This foot is held in a groove in the needle board. Inserting and removing the felting needles from the needle board can be very time-consuming, which is why auxiliary machines are sometimes used to automate this process.Ultimately, even automated insertion and removal of the needles does not solve the problems associated with their handling. According to current technology, these problems arise because the needles, and especially their shanks, are inserted into a hole in the needle board in such a way that the shank is held under tension on its outer surface. This can lead to wear on the needle board, particularly on the cylindrical inner surface of the hole. With advanced wear, the needle board must be replaced or repaired—for example, using plastic sleeves—to prevent the needles from falling out uncontrollably or becoming misaligned within the hole. Felting needles typically have a working section that is significantly reduced in diameter compared to the shank.Between the relatively thick shaft and the working section, the felting needle can have several stepped, reduced sections. During operation, the felting needles are always subjected to bending and kinking stresses. These stepped reduced sections are incorporated into the felting needle depending on the application, in order to provide the necessary stiffness as well as the required elasticity in light of the stresses encountered.

[0002] DE3105358A1 proposes a needle board to reduce some of the aforementioned problems, in which the feet of the felting needles are held in a dovetail-shaped groove.

[0003] EP2218812A1 discloses a shaft section with a maximum diameter and two symmetrically arranged legs as a foot to achieve symmetrical force transmission for the felting needle. EP2218814A1 discloses a shaft section with a larger cross-section compared to adjacent sections such as the shaft and foot. The reduced cross-sectional areas are intended to save mass and achieve a higher working speed. Both of the aforementioned solutions have in common that the otherwise conventional handling of felting needles and the use of conventional needle boards become significantly more difficult or even impossible. Felting needles are also known from CH 343 353 A and CN 102 797 116 A.

[0004] Based on the aforementioned prior art, the object of the present invention can be considered to be to provide a felting needle which allows improved handling with universal applicability in conventional needle boards and auxiliary machines.

[0005] The problem is solved by the felting needle according to claim 1, the needle board according to claim 10 and the method according to claim 13 for inserting a felting needle into a needle board.

[0006] The felting needle according to the invention has a shaft that adjoins a rear end of the needle in its longitudinal direction. Furthermore, the felting needle according to the invention has a working section that adjoins a front end of the needle in its longitudinal direction. The working section is preferably designed to act on fibers during operation in a felting machine. For this purpose, the working section can, for example, have notches, a forked end, or any other design. The shaft is preferably designed to allow the felting needle to be fixed to a needle board. For this purpose, the shaft can have an angled foot section at its end. Furthermore, for fixing the felting needle in a needle board, the shaft can have at least one cylindrical section, which can have a diameter that is matched to the diameter of a through-hole in a needle board into which the felting needle is to be inserted.The shaft comprises a clamping section and a guide section. The guide section is positioned further forward in the longitudinal direction than the clamping section. The clamping section can be cylindrical, at least in part. The guide section can also be cylindrical, at least in part. The guide diameter of the guide section, measured perpendicular to the longitudinal direction, is smaller than the clamping diameter of the clamping section, also measured perpendicular to the longitudinal direction. The felt needle according to the invention is characterized in that the guide diameter is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter.

[0007] Due to the small difference in diameter between the clamping section and the guide section, the felt needles are guided precisely without excessive play during insertion. Furthermore, the smaller diameter of the guide section allows for easy manual insertion without the need for tools. A hammer or similar tool can be used to drive the felt needle into the needle board by striking its rear end (often the foot). The precise guidance and reduced protruding length make the felt needle less likely to bend.A felting needle that is bent during insertion and therefore no longer exactly perpendicular to the board surface can, for example, strike a needle plate, scraper plate, or similar functional element during operation and subsequently bend further and break. Furthermore, repeated, tool-assisted insertion of the felting needle can damage the end of the needle (e.g., the foot). The reduced diameter of the guide section also simplifies removal, as the clamping section is shorter, and less distance needs to be traversed under preload. The stiffness of the felting needle shaft is not significantly reduced. Because the geometry of the felting needle according to the invention deviates only slightly from conventional geometry, no handling problems arise, even in automated machines or when used with existing needle boards.The holes in the needle boards are protected, especially the cylindrical inner surface of the hole. The bond between the aluminum and plastic, which can occur in conventional, multi-layered needle boards, is also subjected to less stress. The stability of the felt needle against the bending and kinking stresses that occur during operation is not significantly reduced. This is particularly advantageous for longer needles. No machining of the shank is necessary during the production of the felt needle, and the high quality of the starting wire (e.g., surface finish) can be maintained.

[0008] The felting needle can have an identification notch in the form of a local indentation in the shaft area. Identification notches are not circumferential and, due to their positioning in close proximity to the base, do not offer any of the advantages of the invention. Furthermore, the felting needle can have one or more reduced sections between the shaft and the working section. A reduced section can have a round cross-section. The diameter of a reduced section can be smaller than the diameter(s) of the shaft, and in particular smaller than the diameter of the clamping section and the diameter of the guide section. The diameter of a reduced section can be more than 12% smaller than the diameter(s) of the shaft. The working section can have a round, triangular, or any other cross-sectional shape.

[0009] The guide diameter of the felting needle according to the invention can be at least 0.5% smaller, preferably at least 1% smaller, than the clamping diameter. Smaller differences between the clamping diameter and the guide diameter do not give the felting needle the effect according to the invention.

[0010] In the felting needle, a foot section can be arranged in the shaft, extending longitudinally towards the rear end of the needle and adjacent to the clamping section. The foot section preferably has a diameter corresponding to the clamping diameter. The foot section preferably has a uniform diameter over its entire length. The foot section can be at an angle to the clamping section, at least in some sections. The foot section can be curved in some sections. The foot section can be cylindrical in some sections. The foot section can be produced by bending a cylindrical shaft. The foot section can be angled at approximately 90° to the clamping section in some sections. The angle between the clamping section and the angled section of the foot section can be between 85° and 90°.The foot section can be designed to position the felting needle lengthwise to the needle board. For this purpose, an angled section of the foot section can rest against the needle board when the felting needle is fully inserted into a through-hole in the needle board.

[0011] The cumulative length, corresponding to the longitudinal distance from the rear end of the felting needle to the front end of the clamping section, can be between 4 mm and 30 mm, preferably between 6 mm and 25 mm. This cumulative length can be the sum of the lengths of the clamping section and, if present, the foot section. Ideally, the cumulative length of the clamping section and the optional foot section can be adjusted so that the clamping section fills the entire bore of the needle board, with the reduced diameter of the guide section located outside the needle board. This ensures optimal support of the felting needle against bending by the needle board and simultaneously protects the needle board bore from excessive wear during needle insertion.Instead of a foot section, the rear end of the felting needle can simply have a cylindrical clamping section or any other means for longitudinally positioning the felting needle relative to the needle board, such as an end-end cross-sectional extension or similar. The total length can in any case correspond to the longitudinal distance from the rear end of the felting needle to the front end of the clamping section.

[0012] The guide section can have a constant guide diameter along its entire longitudinal extent. Alternatively, the guide section can have a guide diameter that is between 0.5% and 12% smaller than the clamping diameter along its entire longitudinal extent. The guide section can be tapered towards the front. Such a conical design of the guide section can be advantageous for certain felting needle applications. However, according to the prior art, most felting needles are not conical but rather have one or more tapers and cylindrical sections. The difference in diameter from the shank, particularly from the clamping shank, to a first taper is regularly 15% or more in prior art felting needles. In practice, fixed steps and sequences of steps have become established, which are almost invariably used by those skilled in the art when designing a felting needle.The length of a standard shank is typically around 30 mm or more. If a reduction of, for example, 15% were introduced up to the needle board, which is often 20 mm thick, a new felting needle would be created whose bending behavior and handling deviate so significantly from the usual standard that an expert would initially consider its function and handling characteristics to be inadequate.

[0013] The guide section can have a longitudinal guide length of at least 5 mm, preferably at least 8 mm. This allows for precise guidance of the felting needle during insertion into the needle board.

[0014] Viewed in the longitudinal direction, a transition section can be arranged between the clamping section and the guide section. The transition section can have a transition diameter that decreases linearly from the clamping diameter to the guide diameter at an angle of between 2° and 15°, preferably between 6° and 10°. The angle can be, for example, 8°. The transition section can have a transition length of at most 5 mm in the longitudinal direction.

[0015] A needle board according to the invention for a felting machine has at least one through-hole. Preferably, the needle board has a plurality of through-holes. The needle board has a felting needle in the at least one through-hole, the needle having a shaft adjoining a rear end of the felting needle in its longitudinal direction and a working section adjoining a front end of the felting needle in its longitudinal direction. The shaft has a clamping section and a guide section, which is arranged further forward in the longitudinal direction than the clamping section. A guide diameter of the guide section, measured perpendicular to the longitudinal direction, is smaller than a clamping diameter of the clamping section, also measured perpendicular to the longitudinal direction. The guide diameter is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter.By arranging a felting needle with a corresponding guide section, the needle board is subjected to less stress when the felting needle is inserted compared to the prior art. This increases the needle board's durability without adversely affecting its usability or handling. An optional foot section of the felting needle can be arranged in an optional groove in the needle board. Since the design of the foot section can conform to the prior art, needle boards with grooves can also be used according to the invention without, for example, limiting the positioning accuracy of the foot in the groove.

[0016] In the embodiment of the inventive method for inserting a felting needle into a needle board, a felting needle, which has a shaft adjoining a rear end of the felting needle in its longitudinal direction and a working section adjoining a front end of the felting needle in its longitudinal direction, wherein the shaft has a clamping section and a guide section which is arranged further forward in the longitudinal direction than the clamping section, a guide diameter of the guide section measured perpendicular to the longitudinal direction is smaller than a clamping diameter of the clamping section measured perpendicular to the longitudinal direction, the guide diameter being at most 12%, preferably at most 9% and most preferably at most 6% smaller than the clamping diameter, is inserted by hand into a through-hole of the needle board and the felting needle is thereby guided precisely in the through-hole of the needle board by the guide section of the felting needle.until the tensioning section of the felting needle is clamped in the through-hole of the needle board, and the felting needle is further inserted into the needle board by means of a tool until it reaches its desired longitudinal position relative to the needle board. The optional foot section of the felting needle can be used to precisely adjust the desired longitudinal position against the needle board, but other methods or means for longitudinal positioning are also applicable according to the invention.

[0017] In the inventive method, the insertion error rate is reduced because the felting needle is precisely guided at the point when insertion requires tool assistance and no longer protrudes from the needle board as far as usual. This significantly reduces the likelihood of the felting needle bending. The inner surface of the needle board bore is subjected to less stress, or for a shorter duration, from the pre-tensioned shaft of the felting needle. Fig. 1 Figure 1 Fig. 2 shows a symbolic overall view of a felting needle according to the invention. Figure 2 Fig. 3 symbolically shows the rear part of the felting needle according to the invention in an enlarged view. Figure 3 The image symbolically shows a cross-sectional view of a felting needle according to the invention in a needle board.

[0018] Figure 1Figure 1 symbolically shows an overall view of a felting needle 1 according to the invention. The felting needle 1 extends along its longitudinal direction x from its rear end, which is in Figure 1 is arranged on the left, up to its front end, which is in Figure 1 The shaft 2 of the felting needle 1 is in Figure 1 The working section 3 is on the left, and the working section 3 is on the right. The working section 3 of the felting needle 1 has a triangular cross-section and a pointed end, as is typical for notched needles. Notches are not shown for simplicity. The felting needle 1 comprises a reduced section 19 between the shaft 2 and the working section 3. All felting needles according to the invention may have one or more of these reduced sections 19, or none at all.

[0019] Figure 2Figure 1 symbolically shows an enlarged view of the rear part of the felting needle 1 according to the invention. The shaft 2 has a tensioning section 4 on the left and a guide section 5 further to the right. In the enlarged view of the Figure 2It can be seen that the guide diameter 6 of the guide section 5 is smaller than the clamping diameter 7 of the clamping section 4. A transition section 10 is arranged between the clamping section 4 and the guide section 5, with a transition diameter 11 that changes from the clamping diameter 7 to the guide diameter 6 from left to right. The felting needle 1 terminates on the left in a bent foot section 8, which is cylindrical except in the bent section and has a foot diameter 9 that corresponds to the clamping diameter 7. In this embodiment, the clamping diameter 7 and the foot diameter 9 are approximately 1.83 mm, which is a common standard for felting needles. The foot section 8 and the clamping section 4 have a combined length of 15 in the longitudinal direction x. The guide section 5 has a length of 16 in the longitudinal direction x.The length 17 of the intermediate transition section 10 is small compared to the sum of the length 15 of the tension section 4 and the foot section 8, but also compared to the length 16 of the guide section 5.

[0020] Figure 3 Figure 1 symbolically shows a cross-sectional view of a felting needle 1 according to the invention in a needle board 12. The needle board 12 has its greatest extent in a plane that is perpendicular to the longitudinal direction x of the felting needle 1. Accordingly, the needle board 12 is the Figure 3The needle board 12 is shown with the needle cut off on the left and right. Four through holes 13 are shown in the needle board 12, arranged along the section line, with the section line passing through the center axis of each hole. A felting needle 1 is positioned in the second through hole 13 from the left and is also shown cut along its longitudinal center axis. The needle board 12 has a groove 14 in which the foot section 8 of the felting needle 1 is positioned. For clarity, the foot section 8 of the felting needle is shown such that it does not fill the groove 14 of the needle board 12 in the direction of the longitudinal direction x of the felting needle 1. When the felting needle 1 is fully inserted into the needle board, it touches—unlike in the Figure 3 depicted - the in Figure 3 lower side of the foot section 8 the groove base 18 of the groove 14. In addition, the Figure 3upper side of foot section 8 up to the upper edge of groove 14, because the felting needle 1 is in Figure 3 from above along the longitudinal direction x of the felting needle 1 into the needle board 12 by blows of a tool not shown in Figure 3 must be turned downwards. As in Figure 3 As can be seen, the tension section 4 of the felting needle 1 extends only slightly downwards beyond the needle board 12. Reference symbol list 1 Felting needle 2 shaft 3 work section 4 Tensioning section 5 Guided section 6 guide diameter 7 Clamping diameter 8 Foot section 9 Foot diameter 10 Transition section 11 Transition diameter 12 needle board 13 through hole 14 Nut 15 summed length 16 Guide length 17 Transition length 18 Groove base 19 reduced section x Longitudinal direction

Claims

1. Felting needle (1) comprising a shank (2) adjacent to a rear end of the felting needle (1) in its longitudinal direction (x) and a working section (3) adjacent to a front end of the felting needle (1) in its longitudinal direction (x), wherein the shank (2) comprises a clamping section (4) and a guide section (5) arranged closer to the front end in the longitudinal direction (x) than the clamping section (2), a guide diameter (6) of the guide section (5), measured perpendicular to the longitudinal direction (x), is smaller than a clamping diameter (7) of the clamping section (4), measured perpendicular to the longitudinal direction (x), characterized in that the guide diameter (6) is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter (7).

2. Felting needle (1) according to claim 1 characterized in that the guide diameter (6) is at least 0.5%, preferably at least 1%, smaller than the clamping diameter (7).

3. Felting needle (1) according to one of the preceding claims characterized in that at the shank (2) in the direction towards the rear end of the felting needle (1) in its longitudinal direction (x), a crank section (8) is arranged adjacent to the clamping section (4), wherein the crank section (8) has a crank diameter (9) which corresponds to the clamping diameter (7) and extends at least in sections at an angle to the clamping section (4).

4. Felting needle (1) according to claim 3 characterized in that the crank section (8) extends in a curved manner at least in a section of its extension.

5. Felting needle (1) according to one of the preceding claims characterized in that a total length (15), which corresponds to the distance in the longitudinal direction (x) from the rear end of the felting needle to the front end of the clamping section (4), is between 4 mm and 30 mm, preferably between 6 mm and 25 mm.

6. Felting needle (1) according to one of the preceding claims characterized in that the guide diameter (6) of the guide section (5) is constant over its entire length in the longitudinal direction (x), or the guide diameter (6) of the guide section (5) is over its entire length in the longitudinal direction (x) between 0.5% and 12% smaller than the clamping diameter (7).

7. Felting needle (1) according to one of the preceding claims characterized in that the guide length (16) of the guide section (5) is at least 5 mm, preferably at least 8 mm, in the longitudinal direction (x).

8. Felting needle (1) according to one of the preceding claims characterized in that a transition section (10) is arranged in the longitudinal direction (x) between the clamping section (4) and the guide section (5), which transition section (10) comprises a transition diameter (11) that decreases linearly at an angle between 2° and 15°, preferably between 6° and 10° from the clamping diameter (7) to the guide diameter (6).

9. Felting needle (1) according to claim 8 characterized in that a transition length (17) of the transition section (10) is at most 5 mm in the longitudinal direction (x).

10. Needle board (12) for a felting machine, which needle board (12) comprises at least one through hole (13) and which comprises a felting needle (1) disposed in the at least one through hole (13), which felting needle comprises a shank (2) which adjoins a rear end of the felting needle (1) in its longitudinal direction (x), and a working section (3) which adjoins a front end of the felting needle (1) in its longitudinal direction (x), wherein the shank (2) has a clamping section (4) and a guide section (5) which is arranged closer to the front end in the longitudinal direction (x) than the clamping section (2), a guide diameter (6) of the guide section (5), measured perpendicular to the longitudinal direction (x), is smaller than a clamping diameter (7) of the clamping section (4), measured perpendicular to the longitudinal direction (x), characterized in that the guide diameter (6) is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter (7).

11. Needle board (12) for a felting machine according to the preceding claim characterized in that a crank section (8) of the felting needle (1) rests against the needle board (12) and the clamping section (4) of the felting needle (1) protrudes a maximum of 10 mm and preferably a maximum of 5 mm from the needle board (12).

12. Needle board (12) for a felting machine according to one of the preceding claims 10 or 11 characterized in that the crank section (8) of the felting needle (1) is arranged in a groove (14) of the needle board (12).

13. Method for inserting a felting needle (1) into a needle board (12) wherein the felting needle (1) comprises a shaft (2) adjoining a rear end of the felting needle (1) in its longitudinal direction (x) and a working section (3) which is adjacent to a front end of the felting needle (1) in its longitudinal direction (x), wherein the shank (2) comprises a clamping section (4) and a guide section (5) which is arranged closer to the front end in the longitudinal direction (x) than the clamping section (2), a guide diameter (6) of the guide section (5), measured perpendicular to the longitudinal direction (x), is smaller than a clamping diameter (7) of the clamping section (4), measured perpendicular to the longitudinal direction (x), the guide diameter (6) is at most 12%, preferably at most 9%, and most preferably at most 6% smaller than the clamping diameter (7), where the felting needle (1) is inserted by hand into a through hole (13) in the needle board (12) and the felting needle (1) is guided precisely by the guide section (5) of the felting needle (1) in the through hole (13) of the needle board (12) until the clamping section (4) of the felting needle (1) clamps in the through hole (13) of the needle board (12), and where the felting needle (1) is further inserted into the needle board (12) with a tool until the felting needle (1) has reached its desired longitudinal position relative to the needle board (12).

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