CYLINDRICALLY SHAPED CARBON FIBRE REINFORCED PART AND METHOD FOR ITS MANUFACTURE

Abstract

The present invention relates to a device, for example a machine part, comprising:—a body with a cylinder shape of substantially carbon fibers with the fibers in the longitudinal direction of the cylinder shape, the body functioning as carrier body with a carrier surface, and—at least a single circumferential body of a plastic provided through injection molding on the body, the circumferential body being provided on at least a part of the carrier surface. Further, the present invention concerns a method for manufacturing the device, comprising:—manufacturing with pultrusion the cylinder shape of substantially carbon reinforced fiber material with carbon fibers substantially in the longitudinal direction of the cylinder shape, and—injection molding of a plastic on the cylinder shape for obtaining the circumferential body on at least a part of the carrier surface.

Claims

1. A machine part of a sorting machine for eggs, comprising: a body with a cylinder shape of substantially carbon fibers with the fibers in the longitudinal direction of said cylinder shape, said body functioning as carrier body with a carrier surface, and adjacent circumferential bodies of a plastic provided through injection molding on said body, the circumferential bodies being provided on at least a part of the carrier surface, wherein on the carrier body, spacers adjacent circumferential bodies are provided through injection molding.

2. The machine part according to claim 1, wherein the carrier surface through injection molding is provided with a shaft covering (M) with an array of circumferential bodies.

3. The machine part according to claim 1, characterized in that the plastic comprises substantially a thermoplast.

4. The machine part according to claim 3, characterized in that the thermoplast comprises substantially TPE, for example TPU.

5. The machine part according to claim 3, characterized in that the thermoplast comprises substantially PBT, or POM, or PA, or PVC.

6. The machine part according to claim 1, characterized in that the machine part comprises a hollow cylindrical shaft.

7. The machine part according to claim 1, characterized in that each circumferential body comprises a diabolo-shaped roller element.

8. The machine part according to claim 1, characterized in that the machine part comprises a hollow tube of square cross section.

9. The machine part according to claim 1, characterized in that the machine part comprises a hollow tube of rectangular cross section.

10. A sorting machine for eggs, comprising at least one device, the device comprising: a body with a cylinder shape of substantially carbon fibers with the fibers in the longitudinal direction of said cylinder shape, said body functioning as carrier body with a carrier surface, and an array of circumferential bodies of a plastic provided through injection molding on said carrier body, the circumferential bodies being provided on at least a part of the carrier surface, wherein the carrier body is embedded in a covering comprising the array of circumferential bodies, the sorting machine preferably comprising an array of such devices.

11. The sorting machine according to claim 10, wherein each device comprises a hollow shaft body having thereon diabolo-shaped roller bodies.

12. The sorting machine according to claim 11, wherein covering parts extend between the rolling bodies.

13. The sorting machine according to claim 10, wherein the carrier body is completely surrounded by the array of circumferential bodies and optional intermediate spacers.

14. The sorting machine according to claim 10, wherein the sorting machine includes an array of roller shafts with circumferential bodies, wherein the shafts extend parallel to each other, and are each provided with an array of diabolo-shaped rollers, such that the roller bodies of adjacent shafts define nests for carrying eggs.

15. A method for manufacturing a device with a cylinder shape, the device being a machine part of a sorting machine for eggs, functioning as carrier body with carrier surface, provided with at least a single circumferential body, comprising: manufacturing with pultrusion the cylinder shape of substantially carbon reinforced fiber material with carbon fibers substantially in the longitudinal direction of the cylinder shape, and injection molding a plastic on the cylinder shape for obtaining circumferential bodies on at least a part of said carrier surface wherein on the carrier body, spacers between adjacent circumferential bodies are provided through injection molding.

16. The method according to claim 15, characterized in that the plastic comprises substantially a thermoplast.

17. The method according to claim 16, characterized in that the thermoplast comprises substantially TPE, for example TPU.

18. The method according to claim 16, characterized in that the thermoplast comprises substantially PBT, or POM, or PA, or PVC.

19. The method according to claim 15, characterized in that for the injection molding of said thermoplast on the cylinder shape, an injection angle α is chosen with 0≤α≤90 with respect to said longitudinal direction, with α in degrees, and preferably an injection angle α that is less than 90 degrees, for example an angle α in the range of 0-70 degrees, in particular an angle α in the range of 0-45 degrees.

20. The method according to claim 15, characterized in that for the injection molding of said plastics on the cylinder shape, a fluid pressure p is chosen with 50≤p≤1000, with p in bar.

21. The method according to claim 15, characterized in that for the injection molding of said plastics on the cylinder shape, an injection molding operating temperature T is chosen with 10≤T≤300, with T in degrees centigrade.

22. The method according to claim 15, characterized in that the cylinder shape manufactured with pultrusion, viewed in longitudinal direction thereof, has a constant outer circumference, and for instance includes no portion reduced in diameter, wherein the cylinder shape manufactured with pultrusion retains the constant outer circumference during the injection molding thereon of the circumferential body.

23. The method according to claim 15, characterized in that the cylinder shape manufactured with pultrusion is provided with a shaft covering (M) with circumferential bodies (10; 102-104), in particular such that the cylinder shape is completely surrounded by the shaft covering (M).

24. The method according to claim 15, wherein the cylinder shape manufactured with pultrusion is substantially not deformed and/or heated prior to and during the injection molding of the plastic on that cylinder shape.

Description

[0040] In the following, the invention is explained in detail on the basis of a drawing, in which:

[0041] FIG. 1 gives an isometric view of a first exemplary embodiment of a machine part where the invention can be used,

[0042] FIG. 2 gives an isometric view of the machine part according to FIG. 1 where the invention has been used,

[0043] FIG. 3 gives a cross section showing the machine part of FIG. 1 according to the prior art,

[0044] FIG. 4 gives a cross section showing the machine part of FIG. 1 according to the present invention,

[0045] FIG. 5 gives an isometric view of a second exemplary embodiment of a machine part where the invention can be used,

[0046] FIG. 6 gives an isometric view of the machine part according to FIG. 5 where the invention has been used; and

[0047] FIG. 7 shows schematically a top plan view of a part of an egg sorting machine with roller shafts.

[0048] In these FIGURES, for the same parts and particulars, the same reference numerals and indications will be used.

[0049] In FIG. 1, in an isometric view, a machine part of a sorting machine, more particularly an egg sorting machine, is shown. There is represented a so-called roller shaft 1 of circular cross section, comprising a hollow shaft body 2, of a suitable type of steel, having circumferential bodies provided thereon through injection molding, in particular diabolo-shaped roller bodies 3 (sometimes also referred to as hourglass-shaped roller bodies 3). Such shafts 1 are preferably (for instance in the sorting machine mentioned) connected at both ends with two respective endless chains (or like transmission elements), in particular for the purpose of (motor) drive. Each two successive roller bodies 3 on these roller shafts 1 can form a carrier position for an egg. The array of circumferential bodies 3 may for instance have mutually the same shape and dimensions.

[0050] An example of an array of roller shafts 1 with circumferential bodies (for example of an egg sorting machine) is represented in FIG. 7. The roller shafts 1 may for instance be part of an endless conveyor 30. In particular, the shafts 1 extend parallel to each other, and are each provided with an array of roller bodies 3, generally diabolo-shaped rollers, such that the roller bodies 3 of adjacent shafts define nests for carrying products (for example, eggs E). A transport or conveying direction of the conveyor 30 is in particular at right angles to the longitudinal direction of each of the roller shafts 1. A drive, for example one or more electric motors, transmission means and the like, are not represented since the configuration of such a roller conveyor as such is generally known.

[0051] To those skilled in the art, it will be clear that for the roller bodies 3 suitable plastics are chosen and also that for conveying such delicate products without damage, high accuracies for these machine parts are required.

[0052] It has been found, however, that, given intensive use, which includes regular thorough chemical cleaning, the properties of these roller shafts 1 with roller bodies 3 change. The shaft bodies prove to bend to some extent and the roller bodies exhibit wear, due both to their being used much and to the cleaning.

[0053] FIG. 2 shows in isometric view a same type of shaft, for example a roller shaft 1, with the shaft body 20 substantially manufactured by pultrusion of carbon fiber material (FIG. 2 shows in particular the shaft body 20 of a roller shaft 1). More particularly, the pultrusion process is so executed that the carbon fibers substantially follow the direction of the shaft and are embedded in a matrix (or filler) of epoxy resin.

[0054] For such a machine part, this combination of materials has suitable mechanical properties, in particular as regards weight, wear, and flexibility, and is more suitable than the steel used heretofore. The percent of fiber in this matrix is between 50% and 80%. The fibrous material is of a generally used type, for instance from the firm of Mitsubishi, for instance having fiber strengths greater than 4000 MPa.

[0055] As follows from FIG. 2, the shaft body of the roller shaft has for instance a constant outer diameter (viewed in the shaft longitudinal direction). In other words, the shaft body preferably does not have any local portion reduced in diameter.

[0056] In FIG. 3 there is represented, according to the prior art, a cross section of a part of a roller shaft 1 of circular cross section having provided thereon by injection molding a shaft covering 5 and a roller body 3. More particularly, a steel shaft body has been overmolded with first covering parts 51 of PA, each provided with two collar edges 52.

[0057] Thereafter, by injection molding, roller bodies 3 have been provided which join these and, as mentioned above, are diabolo-shaped. These roller bodies 3 are formed from a mixture of PVC and NBR.

[0058] FIG. 4 shows a part of a device according to an exemplary embodiment of the invention. The device comprises, for example, a machine part, in particular a part of a sorting machine for eggs (see FIG. 7), comprising: [0059] a body with a cylinder shape 20 of substantially carbon fibers with the fibers in the longitudinal direction of the cylinder shape, the body functioning as carrier body with a carrier surface, and [0060] at least a single circumferential body 10 of a plastic provided by injection molding on the body 20, the circumferential body 10 being provided on at least a part of the carrier surface.

[0061] In FIG. 4 there is shown, in particular, a cross section of a part of a roller shaft 1 of circular cross section having provided thereon (at least, on the shaft body 20, shown in FIG. 2, substantially manufactured by pultrusion of carbon fiber material) through injection molding a covering M with roller body 10 consisting of one whole. The machine part shown here has been manufactured according to the present invention, with the shaft 20 preferably consisting of a matrix of epoxy resin with carbon fibers in the length direction of the shaft body shown, and with the overmolding having been executed with substantially a thermoplast, preferably TPU. This combination of materials has proven highly suitable.

[0062] It has been found, for instance, that TPU adheres very well to carbon fiber (with fibers in the longitudinal direction), so that there is no need, for instance, for any (local) reduction in diameter of the carrier tube 20 for the purpose of a proper adhesion. This is a great advantage since it means that no heating (and deformation) of the carrier tube 20 is needed during the injection molding step, so that weakening of that tube can be avoided. In particular, the injection molding step (i.e. the provision on the formed shaft body 20 of the covering with roller bodies 10 and optional spacers 4) is carried out on a non-heated (‘cold’) shaft body 20.

[0063] In particular, the roller bodies 10 jointly form a circumferential body, and are for instance joined together via integral intermediate covering parts M (see FIG. 4). In other words, the covering M and roller bodies 10 are preferably manufactured as a whole, i.e. in one piece (in the same injection molding step), and, in particular, provided as one whole on the shaft body 20 already formed by pultrusion. As follows further from FIG. 4, spacer parts 4 of the covering M may be provided between (adjacent) circumferential bodies 10, and, for instance, be manufactured integrally with those circumferential bodies (in the same injection molding step).

[0064] In FIG. 5 an isometric view is shown of a second exemplary embodiment of a machine part where the invention can be used. More particularly, a tube 100 with a tubular body 101 of square cross section is shown. In the same way as mentioned above, this tubular body has been obtained through pultrusion of carbon fiber material. In applications, this tube will again function as a carrier body for further parts that are applied thereon by injection molding, also referred to as overmolding.

[0065] As appears from FIG. 5, the tubular shape has for instance a constant angular outer circumference, viewed in the tube longitudinal direction (i.e. the tube is not provided with any local portion reduced in diameter).

[0066] More particularly, in FIG. 6 the tube 100 shown in FIG. 5 is shown, with machine parts 102-104 provided thereon through injection molding (overmolding), more particularly a tube 100 having thereon six fixing blocks for gripper halves for passing on eggs, for instance as described in NL1029748. Hitherto, these blocks, after extrusion of each such block, were slipped in succession over a steel tube. To those skilled in art it will be clear that the accuracy of each separate block needs to be very high, with even small deviations leading in the usual way to improper configurations, and consequently breakage in the processing of eggs. In addition, this manner of manufacturing is highly time-consuming.

[0067] In this FIG. 6 there are shown the above-mentioned six fixing blocks 102 a-f, with also, at their top shown here, as many grates 103 a-f with click edges for snap-fitting the gripper halves (not shown here), as well as, between these fixing blocks 102 a-f, as many spacers 104 a-f which are to ensure the mutual distance between the grippers. This whole of formerly loose parts is now, according to the present invention, provided as a whole by injection molding (overmolding) on the tubular body 101. In this application, mostly POM is used as plastic.

[0068] Further thermoplasts as generally known, and especially suitable for the application described here, are, by way of example and not limited thereto, TPE, TPS, TPO, TPV, TPC, TPA, TPZ, SBS, TPEE, PE derived compounds, PBT, POM, PA, (liquid) silicone rubbers, as well as several rubber compounds such as SBR, IR, IRR, NR, CSM, EPM, VMQ, AU, or ACM. Further, preferably hardnesses shore A and shore D apply, established when these materials are ready for use, that is, 24 hours after the end of the injection molding process, as is known to those skilled in the art.

[0069] Clearly, all possible surface profiles can be chosen, with closed circumferences (closed describing lines), in the following indicated in a random and non-limiting manner, for example, shaft-shaped, of oval cross section, of rectangular cross section, less or more curved or domed surfaces, et cetera.

[0070] To those skilled in the art it will be clear that such profiles will have many applications, in machine construction as indicated above for egg sorting machines, but also in the automotive industry, or further similar means of transport, see for example products shown at www.ptonlinecom, such as airbag parts.

[0071] Furthermore, the invention provides a method for manufacturing a device with a cylinder shape, for example a machine part functioning as carrier body with carrier surface, provided with at least a single circumferential body, comprising: [0072] extruding for obtaining the cylinder shape of substantially carbon reinforced fiber material with carbon fibers substantially in the longitudinal direction of the cylinder shape, and [0073] injection molding of plastics on the cylinder shape for obtaining the circumferential body on at least a part of the carrier surface.

[0074] Injection molding, more particularly overmolding of carrier bodies, is generally known (see the references specified hereinabove). It has been found that set-ups can be used that allow automation.

[0075] In particular, for injection molding of the above-mentioned plastics on the cylinder shape, an injection angle α is chosen with 0≤α≤90 with respect to the longitudinal direction mentioned, with α in degrees, and preferably an injection angle α that is less than 90 degrees, for example an angle α in the range of 0-70 degrees, preferably an angle α in the range of 0-45 degrees.

[0076] It has been found that by the use of an injection angle of less than 90 degrees, deformation of the cylinder shape can be avoided or reduced, in particular at an injection angle of less than about 70 degrees and more particularly at an angle of less than 45 degrees. In particular, the cylinder shape is not locally deformed (e.g. by heating), and use of a strengthening insert can be avoided.

[0077] In a further embodiment, for the injection molding of the above-mentioned plastics on the cylinder shape, a fluid pressure p is chosen with 100≤p≤1000, with p in bar.

[0078] In yet a further embodiment, for the injection molding of the above-mentioned plastics on the cylinder shape, an injection molding operating temperature T is chosen with 100≤T≤300, with T in degrees centigrade.

[0079] To those skilled in the art it will be clear that the invention is not limited to the exemplary embodiments described. Various modifications are possible within the scope of the invention as set forth in the claims.