Insert made of a textile fabric

Abstract

The disclosure relates to an insert (5) made of a textile fabric for being received in a jacket wall of a cylindrical case (6) made of a combustible, felted fibrous material, wherein in particular embodiments the textile fabric includes one, several, or a plurality of yarns which along a longitudinal direction (L) of the insert form a plurality of mesh rows (18) which each include a plurality of meshes (19, 20, 21) that extend in a circumferential direction (U) of the insert.

Claims

1. A textile fabric insert (5) configured for being received in a jacket wall of a cylindrical case (6), wherein the case comprises a combustible, felted fibrous material and is adapted for receiving granular propellant powder, wherein the textile fabric is stretchable and includes a knitted, woven and/or crocheted fabric comprising a natural fiber yarn and a natural fiber-plastic blended yarn.

2. The insert according to claim 1, wherein the textile fabric includes only one layer.

3. The insert according to claim 1, wherein the natural fiber yarn is cotton.

4. The insert according to claim 1, wherein the natural fiber-plastic blended yarn comprises polyurethane.

5. The insert according claim 1, wherein the natural fiber yarn comprises a proportional yarn content and/or a weight content of 30% to 50% in the textile fabric and/or the natural fiber-plastic blended yarn-comprises a proportional yarn content and/or a weight content of 50% to 70% in the textile fabric.

6. The insert according to claim 5, wherein the proportions of natural fiber yarn and natural fiber-plastic blended yarn are 50/50.

7. The insert according claim 1, wherein the natural fiber-plastic blended yarn has a content of natural fiber from 70% to 95% and/or a content of plastic fiber from 5% to 30%.

8. The insert according to claim 7, wherein the proportions of natural fiber to plastic fiber are 89/11.

9. The insert according to claim 1, wherein the insert (5) is formed as a hose.

10. The insert according to claim 9, wherein in an unstretched state the hose has a diameter in the range from 40 mm to 155 mm.

11. The insert according to claim 9, wherein the hose is seamless.

12. The insert according to claim 9, wherein the insert (5) is formed as a single layer and is both axially and radially stretchable.

13. The insert according to claim 9, wherein in the circumferential direction (U) of the hose the fabric has a maximum elongation of about 420%.

14. The insert according to claim 9, wherein in the longitudinal direction (L) of the hose the fabric has a maximum elongation of about 80%.

15. The insert according to claim 1, wherein the textile fabric comprises mutually associated meshes (20) and adjacent mesh rows (18), wherein the mutually associated meshes (20) of the adjacent mesh rows (18) each are guided on the same radial side of the hose of the insert.

16. The insert according to claim 15, wherein the adjacent meshes (20) of a mesh row (18) are guided only on different radial sides.

17. The insert according to claim 1, wherein the textile fabric has a mesh row density (MRZ) in the range from 10 to 13 mesh rows per centimeter.

18. The insert according to claim 1, wherein the fabric has a wale density (MSZ) or a mesh density in the range from 10.5 to 13.5 meshes or wales per centimeter.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further advantages and possible applications of the invention can be taken from the following description in connection with the Figures.

(2) FIG. 1 schematically shows a case comprising an insert according to an exemplary embodiment of the invention as part of a cartridge.

(3) FIG. 2 shows a photo of a case of FIG. 1 after a fracture test with an insert partly exposed in the fracture area.

(4) FIG. 3 schematically shows a section of the knitwear which forms the insert of the case of FIGS. 1 and 2.

DESCRIPTION OF EXAMPLE ASPECTS AND EMBODIMENTS

(5) As an exemplary embodiment, FIG. 1 schematically shows a case 6 as part of a cartridge 1. The case is oblong and circularly cylindrical and receives the granular propellant powder 4 in its interior. In the jacket wall of the case 6 an insert 5 according to an embodiment of the invention is embedded. At the lower end of the cartridge 1 a bottom 2 made of brass is mounted with a primer 3.

(6) The case 6 is made of felted cellulose and nitrocellulose fibers as well as conventional additives. The embedded insert 5 is an expandable hose which has been fabricated without seams from a knitwear 12, here by way of example a woven, crocheted and/or knitted fabric. Due to its illustrated embedment into the case 6, its middle axis coincides with the middle axis of the case.

(7) The hose is manufactured from 50% normal cotton yarn and 50% polyurethane-cotton blended yarn, wherein experiments have also revealed a variant with one third of cotton yarn and two thirds of polyurethane-cotton blended yarn as a good material for the hose. In both cases, the blended yarn has a core of polyurethane, which is sheathed with cotton. In the exemplary embodiment, the blended yarn has a composition of 89% cotton and 11% PUR, wherein in different embodiments a PUR content from 5% to 20%, especially between 5% and 20%, is possible.

(8) Due to its formation as knitwear 12, the hose forming the insert is highly stretchable. The stretchability in the axial direction of the case is additionally supported by the polyurethane-cotton blended yarn.

(9) When the case 6 is damaged by mechanical action, so that a crack, a gap or another fracture opening is obtained in the jacket wall, the insert is exposed in the fracture opening and stretched there to such an extent that without tearing it keeps the fracture opening closed against the granular propellant powder in the interior of the case.

(10) At an outside diameter from 50 mm to 170 mm, especially between 50 mm and 170 mm, and a length from 35 cm to 75 cm, especially between 35 cm and 75 cm, a typical case according to the invention has a jacket wall thickness of 1.5 mm to 4 mm, in particular of 2.5 mm. When manufacturing the case, the insert is mounted with a slight elongation of about 10% and in the unstretched state therefore has a diameter of from 40 to 155, especially between 40 and 155 mm.

(11) FIG. 2 shows a photo of a case of FIG. 1 after a fracture test with an insert 5 partly exposed in a fracture area 8. The arrangement of the insert 5 between a radially inner part 6a and a radially outer part 6b of the case 6 is clearly visible. A felting 10 formed by the meshes of the insert 5 also is partly visible.

(12) The dark lettering on the outer part 6b of the case 6 originates from the sample designation of the fracture test carried out and is irrelevant here.

(13) FIG. 3 schematically shows a section of the knitwear 12 which forms the hose of the insert 5 of the case 6 of FIGS. 1 and 2.

(14) Experiments of the applicant have revealed that the insert 5 as knitwear 12, in particular as woven, crocheted and/or knitted fabric, provides very high strengths and large elongation values at a relatively low weight per unit area and a low radial dimension of the hose. Such textile fabrics are manufactured for example on circular knitting machines. By means of a circular knitting machine, for example a seamless tubular insert like in the illustrated exemplary embodiment can be manufactured.

(15) To provide for very high elongations of the insert 5, a particular mesh weave 14 is used in the exemplary embodiment. A weave image 16 of this mesh weave 14 is shown in FIG. 3.

(16) The weave image 16 sectionally shows a plurality of mesh rows 18, which are arranged one above the other in the vertical direction of the representation of FIG. 3, and a plurality of wales 20, which are arranged one beside the other in the transverse direction of the representation of FIG. 3. In the exemplary embodiment, the vertical direction of the representation of FIG. 3 corresponds to a longitudinal direction L of the insert 5 or the case 6; the transverse direction corresponds to the circumferential direction U of the insert 5 or case 6.

(17) At its lower end, each mesh 20.2 is guided through the corresponding mesh 20.3 of the adjoining lower mesh row 18.3 and in turn guides the corresponding mesh 20.1 of the adjoining upper mesh row 18.1.

(18) The mutually associated meshes 20 of the adjacent mesh rows 18 form a wale 23 and each are guided on the same radial side of the hose of the insert; i.e. either all on the outside or all on the inside.

(19) Adjacent meshes 20 of a mesh row 18 always are guided on the respective other radial side; i.e. when the one adjacent mesh 20 is guided on the inside, the adjacent meshes 19 and 21 each are guided on the outside, and when the one adjacent mesh is guided on the inside, the adjacent meshes each are guided on the inside.

(20) In the exemplary embodiment of the case, from ten to 13 (thirteen), especially between ten and 13 (thirteen), mesh rows per centimeter of longitudinal extension are provided in the knitwear in the unstretched state of the insert (MRZ=number of mesh rows, in FIG. 3 its reciprocal is depicted), in particular from 11.5 to 12, especially between 11.5 and 12, mesh rows. The indication in terms of mesh rows per two centimeters also is common practice: In this case, the insert has a fabric image with from 20 (twenty) to 26 (twenty-six), especially between 20 (twenty) and 26 (twenty-six), mesh rows per two centimeters of longitudinal extension, in particular from 23 to 24, especially between 23 and 24, mesh rows per two centimeters.

(21) With regard to the wales 23, from 10.5 to 13.5, especially between 10.5 and 13.5, wales per centimeter of circumferential extension are provided in the fabric image in the unstretched state of the insert (MSZ=number of wales, in FIG. 3 its reciprocal is depicted), in particular from 11.75 to 12.25, especially between 11.75 and 12.25, wales. The indication in terms of wales per two centimeters also is common practice: In this case, the insert has a fabric image with from 21 (twenty-one) to 27 (twenty-seven), especially between 21 (twenty-one) and 27 (twenty-seven), wales per two centimeters of circumferential extension, in particular from 23.5 to 24.5, especially between 23.5 and 24.5, wales per two centimeters.

(22) In a state mounted on the case, the insert in this exemplary embodiment has a fabric elongation, in particular in the circumferential direction U (or radial direction R) of the case and/or in the longitudinal direction L of the case, of 5% to 20% as compared to the unstretched state, in particular of about 11%. This stretched state also is the stretched state shown in FIG. 2, at least with regard to the order of magnitude, when the slight additional elongation due to the displacement at the fracture point remains neglected.

(23) In the transverse direction of the representationhence in the circumferential direction U of the hosethe seamless tubular insert 5 used in the exemplary embodiment has a maximum elongation of about 420%. In the vertical direction of the representationhence in the longitudinal direction L of the hosethe maximum elongation is about 80%. A maximum elongation in the radial direction of the hose of the insert 5 can be calculated from or with the hose diameter in the unstretched state and the maximum elongation in the circumferential direction U of the hose, possibly by taking account of an additional elongation in the longitudinal direction L.

(24) For the material of the insert 5 for example cellulosic fibers can be used, which are used in a single variety (100% cellulosic fibers) or in a fiber blend (for example cotton fibers with a synthetic material such as PUR).

(25) Due to the (actually expert) matching of the fiber thicknesses and the technological parameters of the yarn and knitwear production, the desired felting quality of the case (when felted through the insert) is achieved proceeding from the exemplary embodiment, i.e. it is ensured that the fiber mass gets caught in the mesh shanks of the textile and hence prevents a separation or splitting of the case body.

LIST OF REFERENCE NUMERALS

(26) 1 cartridge 2 bottom 3 primer 4 propellant powder 5 insert 6 case 6a inner part of the case 6b outer part of the case 8 fracture area 10 felting 12 knitwear 14 mesh weave 16 weave image 18 mesh row 19, 20, 21 mesh 23 wale L longitudinal axis/direction U circumferential direction R radial direction MRZ number of mesh rows MSZ number of wales