Abstract
The present invention relates to a feeder system for metal casting. The feeder system comprises a feeder sleeve mounted on a tubular body. The feeder sleeve has a longitudinal axis and comprises a continuous sidewall that defines a cavity for receiving liquid metal during casting. The sidewall extends generally around the longitudinal axis and has a base adjacent the tubular body. The tubular body defines an open bore therethrough for connecting the cavity to the casting. A groove extends into the sidewall from the base to a first depth and the tubular body projects into the groove to a second depth and is held in position by retaining means. The second depth being less than the first depth so that upon application of a force in use the retaining means are overcome and the tubular body is pushed further into the groove.
Claims
1. A feeder system for metal casting comprising a feeder sleeve mounted on a tubular body; the feeder sleeve having a longitudinal axis and comprising a continuous sidewall that defines a cavity for receiving liquid metal during casting, the sidewall extending around the longitudinal axis and having a base adjacent the tubular body; the tubular body defining an open bore therethrough for connecting the cavity to the casting, wherein a groove extends into the sidewall from the base to a first depth and the tubular body projects into the groove to a second depth and is held in position by retaining means, the second depth being less than the first depth so that upon application of a force in use the retaining means are overcome and the tubular body is pushed further into the groove.
2. The system of claim 1, wherein the retaining means comprise a retaining element or retaining elements which releasably hold the tubular body in position at the second depth.
3. The system of claim 1, wherein the retaining means comprise the tubular body having at least one integral retaining element.
4. The system of claim 3, wherein the at least one integral retaining element is a projection from the tubular body.
5. The system of claim 4, wherein the projection is an outward projection.
6. The system of claim 4, wherein the projection is a wing, notch or rib.
7. The system of claim 1, wherein the tubular body has a thickness of no more than 3 mm.
8. The system claim 1, wherein the tubular body is made from metal or plastics.
9. The system of claim 8 wherein the metal is steel with a carbon content of less than 0.05% by weight.
10. The system of claim 1, wherein the first depth is at least 20 mm.
11. The system claim 1, wherein the tubular body has a height measured along a bore axis and the first depth is from 20 to 80% of the height of the tubular body.
12. The system of claim 1, wherein the groove has a maximum width measured in a direction approximately perpendicular to a bore axis of no more than 10 mm.
13. The system of claim 1, wherein the second depth is no more than 50% of the first depth.
14. The system of claim 1, wherein the groove is located at least 5 mm from the feeder sleeve cavity.
15. A process for preparing a mould comprising placing the feeder system of claim 1 on a pattern; surrounding the pattern with mould material; compacting the mould material; and removing the pattern from the compacted mould material to form the mould; wherein the compacting the mould material comprises applying pressure to the feeder system such that the retaining means are overcome and the tubular body is pushed further into the groove to a third depth.
16. The process of claim 15, wherein the retaining means are overcome such that the tubular body is pushed further into the groove to a third depth, the third depth being at least 50% of the first depth.
17. The process of claim 15, wherein compacting the mould material comprises applying a ram up pressure of at least 30 N/cm.sup.2.
Description
(1) Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:
(2) FIG. 1 is a perspective drawing of a feeder system in accordance with an embodiment of the invention;
(3) FIG. 2 shows a feeder system in accordance with an embodiment of the invention prior to ram-up (FIG. 2a) and after ram-up (FIG. 2b);
(4) FIG. 3 is a schematic drawing of deformation of a retaining element in accordance with an embodiment of the invention;
(5) FIG. 4 and FIG. 5 show tubular bodies for use in a feeder system in accordance with embodiments of the invention;
(6) FIG. 6 shows a tubular body for use in a further embodiment of the invention;
(7) FIG. 7 shows a feeder system incorporating the tubular body of FIG. 6;
(8) FIG. 8 shows a tubular body having fins for use in an embodiment of the invention;
(9) FIG. 9 shows a tubular body having an overlap for use in an embodiment of the invention;
(10) FIG. 10 shows a feeder system comprising biasing means in accordance with an embodiment of the invention; and
(11) FIG. 11 shows a feeder system comprising a retaining element in accordance with an embodiment of the invention.
(12) FIG. 1 shows a feeder system 10 comprising a feeder sleeve 12 mounted on a tubular body 14. The feeder sleeve 12 is made from exothermic material (although insulating material could also be used) and the tubular body 14 is pressed from sheet steel. The tubular body 14 has a circular cross-section and comprises four integral wings 16 which support the feeder sleeve 12, and which are releasably attached by adhesive.
(13) FIG. 2 is a cross-section of part of the feeder system of FIG. 1 on a moulding pattern plate 6 prior to ram-up (FIG. 2a) and after ram-up (FIG. 2b). A longitudinal axis Z passes through the feeder sleeve 12 and the tubular body 14. Referring to FIG. 2A a continuous sidewall 18 extends around the axis Z and encloses a cavity for a receiving liquid metal during casting. The tubular body 14 defines a bore along the axis Z which forms a passageway for liquid metal to travel from the feeder sleeve cavity to the casting.
(14) The tubular body 14 tapers (narrows) away from feeder sleeve 12 to form a feeder neck 15. The angle ? of the tapered neck relative to the axis Z is approximately 45?. The tubular body 14 comprises wings (also known as tabs) 16. Each wing 16 is formed by making a pair of incisions into the edge of the tubular body 14 and folding the portion between the incisions outwards (approximately 90? to the bore axis Z). As such, the wings 16 are integrally formed outward projections. The wings 16 abut the base 22 of the sidewall 18.
(15) The sidewall 18 has a circular groove 20 (of uniform width) which extends into the wall from its base 22. The groove 20 receives a portion of the tubular body 14. The location of the wings 16 determines how far the tubular body 14 projects into the groove 20, hence the wings are retaining means.
(16) Referring to FIG. 2b there is shown the same feeder system after ram-up. The feeder sleeve 12 has been pushed onto the tubular body 14 deforming the wings 16 (the retaining means have been overcome). The wings 16 are flush with the rest of the tubular body 14 and no longer hold the tubular body 14 in place. Instead the tubular body 14 has been pushed further inside the groove 20. In this case the groove 20 is wide enough to accommodate the wings when flush against the rest of the tubular body 14.
(17) The groove 20 has a depth D1. Prior to ram-up, the tubular body 14 projects into the groove 20 to a second depth D2, approximately 12% of the depth of the groove D1. After ram-up the tubular body projects into the groove 20 to a third depth D3, approximately 75% of the depth D1. Hence, ram-up causes relative movement of the feeder sleeve 12 and the tubular body 14 rather than breakage of the feeder sleeve 12.
(18) FIG. 3 is a schematic diagram of the deformation of a wing 16 as shown in FIGS. 1 and 2. FIG. 3a shows the wing 16 extending outward at an angle approximately 90? to the bore axis Z. FIG. 3b shows the wing 16 being pressed towards the rest of the tubular body 14. FIG. 3c shows the wing 16 folded back against the tubular body; in this position the tubular body 14 can move further into the groove 20.
(19) FIG. 4 shows part of a tubular body 24 for use in another embodiment of the present invention. The tubular body 24 has a number of integral retaining elements in the form of notches 26 (only one is shown). The notch 26 is formed by making a pair of parallel incisions in the tubular body 24, in a region away from the peripheral edge, and pushing the metal outwards so that it stretches. The tubular body 24 can be employed with the feeder sleeve 12 described previously. Prior to ram-up, the notch 26 projects outwards from the tubular body 24 within the groove 20 and grips the sidewall 18 to hold the tubular body 24 at a desired position (friction fit). The friction fit is overcome during ram-up, allowing the tubular body to move further into the groove 20, which has a uniform width. If a feeder sleeve having a tapered groove is employed, then during ram-up the notch 26 will be pressed inwards by the feeder sleeve to allow the tubular body 24 to move further into the groove and be held at the new position i.e. the retaining element will be deformed.
(20) FIG. 5 shows part of a tubular body 28 for use in another embodiment of the present invention. The tubular body 28 has integral retaining elements in the form of shaped notched wings 30 (only one is shown). The wing 26 is formed by cutting a tab from the tubular body, in a region away from the peripheral edge. The tab is pushed outwards and shaped as illustrated i.e. the upper part 30a of the wing extending generally downwardly and is crimped into a shall v-shape. The lower part 30b of the wing is bent outwardly at approximately 90? to the bore axis. The tubular body 28 may be employed with the feeder sleeve 12 described previously; the upper part of the notched wing 30a will be located within the groove 20 with the point of the V 30c griping the inner surface of the sidewall 18 and the lower part 30b will be in contact with the base 22 to support the feeder sleeve 12. The winged notch 30 abuts the feeder sleeve 12 and therefore holds the tubular body 28 in a desired position before ram-up. During ram-up the upper part 30a will be pressed inwards and the lower part 30b will be folded down against the rest of the tubular body 28, to allow the tubular body 28 to move further into the groove 20.
(21) FIG. 6 shows a tubular body 32 in accordance with a further embodiment of the invention. An integral rib 34 encircles the tubular body and is formed by pushing and stretching the metal outwards. The tubular body 32 has an inwardly directed annular lip or flange 36 at its base that sits on the surface of the mould pattern 6 in use, and produces a notch in the resulting metal feeder neck to facilitate its removal (knock off).
(22) FIG. 7 is a feeder system 38 comprising the tubular body 32 of FIG. 6 and a feeder sleeve 40. The feeder system 38 is situated on a pattern plate 6 and moulding pin 42 prior to ram up. The sleeve 40 has a groove 44 that narrows from a maximum width at the base of the sleeve. The tubular body 32 is inserted in the sleeve 40 and the rib 30 grips and holds the tubular body 32 in place against the sides of the groove 44. On ram up, when pressure is applied the sleeve 40 moves downwards and the rib 30 is compressed allowing the tubular body 32 to move further into the narrowing groove 44. i.e. the integral rib 30 is deformed. The top of the moulding pin 42 is located in a complementary recess 46 in the roof 48 of the sleeve 40, and on ram up, as the sleeve moves downwards, the top of the moulding pin 42 pierces the thin section at the top of the roof 48. If desired a collar could be fitted in the recess 46 to avoid the risk of fragments of sleeve breaking off when the pin 42 punctures the roof 48. Alternatively a narrow aperture could extend through the roof 48 in place of the recess 46 and thereby accommodate the support pin 42. In this case the aperture would have a diameter corresponding to approximately 15% of the maximum diameter of the feeder sleeve cavity.
(23) It will be understood that the tubular body 32 of FIG. 6 could be employed with a feeder sleeve having a groove of uniform width, instead of the tapered groove 44. If the tubular body 32 were employed with the feeder sleeve 12 having the uniform groove 20, no deformation would occur on ram-up. The rib 30 would grip and hold the tubular body in place against the sides of the groove 20 (friction fit) at the second depth. On ram up, when pressure is applied the sleeve 12 moves downwards and the friction is overcome allowing the tubular body to move further into the groove 20.
(24) FIG. 8a is a section through a tubular body 50 that is pressed from sheet steel for use with a feeder sleeve. FIG. 8b is a lateral cross-section of the tubular body 50 and shows that the body has a circular cross-section and comprises four integral fins 52. In use the fins 52 hold the tubular body 50 in place within a groove in a feeder sleeve (friction fit). The tubular body 50 can be employed with a feeder sleeve having a groove of uniform width (e.g. the feeder sleeve 12) or a tapered groove (e.g. the feeder sleeve 40). In both cases the friction fit between the fins 52 and the groove is overcome on ram-up, allowing the tubular body 50 to be pushed further into the groove. The fins 52 are made from pressed steel, which is harder than feeder sleeve material, and do not deform on ram-up.
(25) FIGS. 9a and 9b are sections through a tubular body 54 that is pressed from sheet steel for use with a feeder sleeve. Referring to FIG. 9a, one end of the tubular body 54 is tapered to form a feeder neck 56 with an inwardly directed lip or flange 58 and the opposite end is folded over to provide a portion of overlap 60. FIG. 9b shows that the tubular body 54 has a circular cross-section.
(26) The tubular body 54 can be employed with a feeder sleeve having a groove of uniform width (e.g. the feeder sleeve 12) or a tapered groove (e.g. the feeder sleeve 40). In both cases a friction fit between the overlap 60 and the groove holds the body in place in the groove at the second depth. This friction fit is overcome on ram-up, allowing the tubular body 54 to be pushed further into the groove. The overlap 60 is reinforced and does not deform on ram-up. The overlap 48 may cause some abrasion of the feeder sleeve material, especially if employed with a tapered groove.
(27) FIG. 10 shows a feeder system 62 comprising a tubular body 64, a spring 66 and the feeder sleeve 12 (described previously), which has a groove 20 of uniform width. The tubular body 64 is pressed from sheet steel and narrows away from the feeder sleeve 12 to form a feeder neck 68 with an inwardly directed lip or flange 70. The spring 66 provides biasing means which hold the tubular body 64 within the groove 20 at the second depth. On ram-up the biasing means are overcome, allowing the tubular body 64 to be pushed further into the groove 20.
(28) FIG. 11 shows a feeder system 72 comprising a tubular body 74 and the feeder sleeve 40 that has a tapered groove 44. The tubular body 74 tapers in two stages to form s a feeder neck 76 and has an inwardly directed lip or flange 78. The tubular body 74 is fixed in the groove 44 of the feeder sleeve 40 with glue (adhesive) 80h. The glue 80 breaks away from the tubular body 74 and/or the feeder sleeve 40 on ram-up allowing the tubular body to move further into the groove.
