TECHNICAL FIELD:

The invention relates to a divisible mold and a casting method

BACKGROUND DESCRIPTION

Traditional casting usually uses two segments of casting compound (sand, plaster), which the model is squeezed into. This places restrictions on possible shapes for casting, as the model must be pulled straight out of the parts without destroying the mold. For example only smooth rings can be cast, no helical models, etc. There is a need for a simple mold that can cast more complicated shapes.

SUMMARY OF THE INVENTION

The above objectives are achieved by a divisible mold comprising

- a casting bottle comprising a plurality of bottle walls, shaped to be able to form a standing shell in the assembled position;

- an internal segment divider for separating the interior of the casting bottle into a plurality of vertical sectors, one sector per bottle wall

- a strap that can be put around the casting bottle to hold it together and also compress it when it is filled with casting compound; where

- the segment divider and the bottle walls are dimensioned so that the ends of the segment divider in the horizontal direction end up edge to edge with the bottle walls and thus separate them in vertical direction when they are joined together. And of a casting method for the mold comprising the steps: a) The segment divider is inserted into the strap; b) The bottle walls are then inserted into the strap, so that the bottle walls end up edge to edge with the ends of the segment divider, after which the strap is screwed on; c) The sectors are filled with casting compound and compressed to form segments consisting of bottle walls and molding compound; d) Loosen the strap and remove the segment divider; e) Optionally, removal of casting compound on the segments where a casting model is to be placed with the same depth on the model but slightly less radial extent; f) Talking of the inward-facing surfaces of the segments and optionally the surfaces of the casting model; g) Positioning of the casting model with placement of the segments around the casting model and optionally an ingot model and/or air duct model adjacent to the casting model; h) The segments are pressed against the model and the strap is tightened; i) Loosening and removal of straps; j) The segments are removed from the model; The first preferably with a magnet on the corresponding bottle wall; k) If the ingot and/or air duct is not created in step f) it can be created when the segments are extended;

I) The segments are brought together and clamped together. The mold is thus ready for casting.

BRIEF DESCRIPTION OF FIGURES

Fig. 1 shows parts of a casting bottle according to an example.

Fig. 2 shows a stand and a cone from Fig. 1 in more detail. Fig. 3A shows a cross section of a filled casting bottle with segment divider.

Fig. 3B shows a cross section of a filled casting bottle without segment dividers and straps.

Fig. 4 Shows steps A-C according to a casting method.

Fig. 5 shows steps D-G according to the casting method in Fig. 4.

Fig. 6 shows steps H-l according to the casting method in Figs. 4 and 5.

Fig. 7 shows steps A-C according to a further casting method.

Fig. 8 shows steps D-J according to the casting method in Fig. 7.

Fig. 9 shows steps J-L according to the casting method in Figs. 7 and 8.

Fig. 10 shows steps A-C according to a further casting method.

Fig. 11 shows steps D-F according to the casting method in Fig. 10.

Fig. 12 shows steps G-J according to the casting method in Figs. 10 and 11.

Fig. 13 shows steps K-M according to the casting method in Figs. 10, 11 and 12.

DETAILED DESCRIPTION

Figures 1-3 show parts of a mold 100 comprising a casting bottle 105 comprising a plurality of bottlewalls 105a, formed to be able to form standing shells in assembled position, an inner segment divider 101 for separating the interior of the casting bottle 105 into a plurality of vertical sectors, a sector per bottle wall 105a, a base plate 111 on which the bottle walls 105a can be placed, a strap 102 which can be placed around the casting bottle 105 to hold it together and also compress it when it is filled with casting mass.

The casting compound is preferably casting sand, but the mold can also be used for heat resistant plaster. Mold 100 may also include a cone 112 which may form the ingot in the casting bottle and optionally a stand 150.

The segment divider 101 in the example shown is divided into 4 sectors, but 3-8 sectors, which do not have to be evenly distributed in the casting bottle 105, are also conceivable. The bottle walls 105a are as shown example 4 pcs, but can be varied according to the number of segments. In the example shown, the bottle walls 105a are arcuate with respective arc length adapted to their sector, so that the bottle walls together form a cylindrical shell in the assembled position. The bottle walls 105a may have other shapes and form shells which are elliptical, triangular, square, pentagonal, hexagonal, etc. The bottle walls 105a can be made of a ferromagnetic material, this makes it possible to pull out a bottle wall 105a with a magnet. The bottle walls 105a can be numbered 107 and marked with arrows 108 to facilitate the proper assembly of the casting bottle 105.

The strap 102 preferably runs around the casting bottle 105 for more than 1 revolution and less than 2 revolutions, more preferably more than 1.5 revolutions. One or more hose clamps 103 can be used to tighten the strap 102. The number of hose clamps 103 is preferably increased with an even distribution as the height of the casting bottle 105 is increased to obtain an even tension. The strap 102 comprises guide elements, here in the form of hobs 104, for positioning the hose clamps 103 horizontally around the strap 102 when screwing on. The number of hobs 104 can preferably be 4- 6 pcs/hose clamp 103. Instead of hobs 104, for example, horizontal grooves could be arranged on the clamping band 102.

The bottle walls 105a on the inside are provided with at least one protruding inner adhesive element 106, for improved adhesion of casting compound. The adhesive element 106 is arranged to be able to be folded in and lie flat against the respective bottle wall 105a. They are made of a metal strip which is attached in the middle to the bottle wall 105a, for example by soldering, so that the ends of the metal strip can be folded in and out. The metal strips are preferably positioned vertically.

The adhesive elements 106 could also be releasably attached to the bottle walls 105a, for example by screwing on. Adhesive members 106 act as barbs, and in the example shown are shaped as narrow rectangles, with a short central portion of the rectangles attached to the bottle wall 105a. The upper and lower rectangular parts can be bent freely out of the bottle walls 105a. When casting in casting sand, the rectangle parts are bent 10-90 degrees out of the bottle walls 105a, preferably

20-50 degrees, while when casting in e.g. heat-resistant plaster, the barbs can be folded flat against the bottle walls 105a.

The base plate 111 is preferably made of a ferromagnetic material and provided with lines and or circles to visually guide the bottle walls 105a towards a center. The base plate 111 and the bottle walls 105a may be provided with numerical markings 107, 111a to mark the position and in the order in which they are to be brought together.

The cone 112 has a magnet 114 (approx. 25-100 N) in the bottom, which enables an arbitrary placement of the cone on the base plate 111. The cone further comprises a sleeve 115 with internal threads. The sleeve 115 runs from the base of the cone 112 to its tip. A rod 116 with external threads is located in the sleeve 115 to be able to adjust the height of a model attached to the top of the rod. The height can be adjusted with a span, slightly shorter than the height of the cone 112. A sharp tip 117 on the rod 116 facilitates attachment of a model to the cone 112.

The stand 150 is a multi-axis stand having a magnet 151 (> 50 N), which forms the foundation for a vertical rod 152 is attached to the magnet 151. A pierced first cylinder 153a is threaded onto the rod 152 and can be moved up and down along the vertical rod 152 and locked on a preferred height position with a screw. The cylinder 153a has a pierced hole in the cylinder at one base, parallel to its base, and at the opposite base a hinge ball is attached. A rod with a hinge ball at one end is connected by means of ball hinge couplings 155, which has two parallel plates that are clamped around the hinge balls to secure them. A second cylinder 153b is threaded onto the rod 154 and can be moved along that rod 154 and locked at a preferred position with a screw. The cylinder 153b has a pierced hole in the cylinder at one base, parallel to its base, and at the opposite base a hinge ball is attached. An attachment 156 for a grain tweezer 157 has a hinge ball at one end which is connected to cylinder 153b hinge ball via a ball hinge coupling 155. The grain tweezer 157 can be easily clamped and loosened around the model 110.

Figure 3A shows the casting bottle 105 from above filled with sand, with segment divider 101 separating filled sectors, and a strap 102 around the casting bottle. A full sector with associated bottle walls 105a is called segment 109 in this application. The segment divider 101 and the bottle walls 105a are dimensioned so that the ends of the segment divider in the horizontal direction end up edge to edge with the bottle walls 105a and thus separates them vertically when joined together. The diameter of the casting bottle 105 with the bottle walls 105a separated by segment divider 101 is called D. The thickness of the segment divider 101 is h. Figure 3B shows the casting bottle 105 from above when segment divider 101 and strap 102 have been removed. The diameter of the casting bottle in this position is called d. The relation between D and d can be expressed as D = d + 4h / p.

Figs. 4-6 show a casting method for sand casting of spirals, spiral-like shapes and many other shapes with undercuts.

A. The segment divider 101 is inserted into the strap 102.

B. The bottle walls 105a are then inserted into the strap 102, which is screwed on.

C. The casting bottle 105 is filled with casting sand and compacted (eg with a hammer). The strap 102 is loosened and the segment divider 101 is removed. Four segments 109 consisting of the bottle walls 105a and compressed sand have been formed. D. A model 110 is attached to the cone 112, which is placed in the middle of the base plate 111.

The sand surfaces 113 of the segments 109 are talked and placed around the model. The segments 109 are then pushed towards the center of the base plate 111.

E. The strap 102 is pressed down outside the segments 109. The hose clamps 103 are then tightened until the segments 109 are close together.

F. The strap 102 is loosened until it can be pulled straight up and removed from the segments 109.

G. Segments 109 are removed from the model; The first is suitably with a magnet 118, which acts as a handle.

H. An air duct 121 can be easily made by cutting off a comer of a pair of segments 109, which runs down to the model impression 120. The impression 119 of the cone 112 forms an ingot.

I. Segments 109 are brought together, clamped and rotated. The mold 100 is thus ready for casting through the ingot 119.

Figure 7-9 shows a casting method for sand casting of hollow, short (<15 mm) shapes, which allows many types of undercuts (eg a ring with a pattern along the outside).

A. The segment divider 201 is inserted into the strap 202.

B. The bottle walls 205a are then inserted into the strap 202, which is screwed on.

C. The casting bottle 205 is filled with casting sand and compacted (eg with a hammer). The strap 202 is loosened and the segment divider 201 is removed. Four segments 209 consisting of the bottle walls 205a and compressed sand have been formed.

D. A depression 240 is made in the sand with approximately the same depth as the model 210 is long and with walls slightly smaller than the outside of the model.

E. Shows as a cross-section along a vertical plane through the center of the casting bottle. The walls of the segments 209 are talked, and then brought together until the model 210 can be placed in the depression 240. Under the model 210, a thin plate 222 is placed slightly larger than the hole in the middle of the model 201. It is used to allow segments 209 to be pulled apart without breaking. The strap 202 is placed around the casting bottle 205. Tighten the hose clamp 204 until the segments 209 are close together. F. The hole in model 210 is filled with sand and e.g. a screw 223 is pressed down in the middle as a 'reinforcement'.

G. A tubular lid 226 of the same diameter d as the casting bottle 205 without segment divider 201 is attached over the segments 209 with another strap 227.

H. The lid 226 is filled with sand 228, which is compressed. The lid 226 with compressed sand 228 forms an upper segment. The upper strap 227 is loosened.

I. The lid 226 is pulled straight up. A cone-shaped ingot 230 is carved into the compressed sand in the lid 228 and an air duct 231 is made on the diagonally opposite side of the model impression. The strap 202 is loosened around the casting bottle 205.

J. The segments 209 are pulled out of the model, which is removed together with the plate 222 under the model 210.

K. Segments 209 are compressed. An air duct 232 is made at the bottom of the recess 240, so that it ends up directly below the air duct 231 in the compressed sand in the lid 228.

L. The lid 226 and the bottle walls 205a are clamped together and the mold 200 is ready for casting.

Figs. 10-13 show a casting method for sand casting of more irregular shapes, where surfaces between adjacent segments are also used. (In this example a cobra in attack position)

Casting of models that are more irregular differs more from case to case than in the previous series.

Guidelines are to use the layers between the segments and between the lid and the segments, for parts where an imprint between these layers is possible. Otherwise, that part of the model must be placed in the middle of the casting bottle. All parts of the model must be in contact with at least two segments for it to be able to detach from the bottle without damaging the segments with compressed sand. It is usually best to loosen the segments that are easy to remove first. Then the degrees of freedom to loosen the remaining segments increase. Sometimes small modifications to the model can make casting much better and easier.

If you use CAD and 3D printer to make the model, you often see quite clearly how the model should be placed in the best way.

Here is a description of how to cast a cobra in sand: A. The segment divider 301 is inserted into the strap 302.

B. The bottle walls 305a are then inserted into the strap 302, which is screwed on.

C. The casting bottle 305 is fdled with casting sand and compacted with a hammer. The strap 302 is loosened and the segment divider 301 is removed. Four segments 309 consisting of the bottle walls 305a and compressed sand have been formed.

D. A stand 350, which in the figure is a good tool to orient the model in the best way. The stand 350 can be placed anywhere on the base plate 311 since a magnet 351 is attached to the bottom of the stand 350. The orientation is done with adjustable screws 353 and two ball joints 355.

The model 310 is easily attached with a grain tweezer 357 screwed into the stand.

E. Once the model 310 has been attached in a suitable orientation, the talked segments 309 are placed around the model 310, which can also be talked. The part of model 310 where the snake lies flat against the ground is oriented so that its top barely touches the tops of segments 309. It makes it possible to loosen the segments 309 quite easily. Furthermore (assuming the model has scales) you can smooth to the sides of the body, so that virtually this entire part of the body ends up in the lid 326.

F. The segments 309 are compressed around the model 310. In this case, it is the segments 309 in sector 3 and 4 which will have the deepest impressions and the sand surfaces can be easily deformed when they are compressed. The mold will be much better if you first compress the segments 309 in sectors 3 and 4 as far as you can without having to detach the stand 350 from the model 310. Then you pull off these segments 309 and level them to the surfaces. You can also fill the cavities with a little loosely packed sand. The surfaces and cavities are talked again and set back in the same places around the model.

G. Segment 309 can now be properly compressed and screwed together with the strap 302 and the stand 350 removed.

H. The lid 326 is secured over the talked segments 309 (with the markings on top of each other) with a strap 327.

I. The lid 326 is filled with sand, which is compressed. The lid 326 with compressed sand forms an upper segment. Then the strap 327 is loosened between cover 326 and segment 309 and the cover 326 is pulled straight up. Then the strap 302 is loosened and removed for the segments 309. J. A magnet 318 which in the figure acts as a handle. In this case, it is convenient to pull the segments 309 in sectors 1 and 2 straight out in the direction of the arrow. Segments 309 in sectors 3 and 4 are then carefully moved away from the model in the direction of the arrows in the figure. To prevent the model 310 from falling onto the base plate 311 towards the end of the unloading and destroying parts of the imprint, you can loosen segment 309 in sector 3 upwards while holding segment 309 in sector 4 below (instead of next to) sector 3. The model can then be pulled straight up from segment 309 in sector 4.

K. One (or two) air duct (s) 359 is then made from the snake's tail tip in the lid up to the surface of the lid. L. An ingot 360 is carved out. The figure shows vertical cross-sections towards sectors 3 and 2 on the left and towards sectors 1 and 2 on the right.

M. The segments 309 are brought together and clamped. The mold 300 is thus ready for casting.

Figure captions Parts with the same numbering in series 100, 200, 300 have the same function and properties as described for an item.

100. Mold.

101. Segment divider.

102. Thin strap that runs around the bottle in just under 2 turns.

103. Hose clamp that tightens the clamps ( 102) .

104. Hobs for the hose clamps.

105. Casting bottle with bottle walls 105a for the segments.

106. Internal adhesive element.

107. Numbering of the bottle segments.

108. Arrow indicating in which direction the numbering should increase.

109. The segments filled with compressed casting sand

110. The model to be casted.

111. Ferromagnetic base plate with number markings 111a. A cone, which forms the ingot in the mold. Talked sand surfaces on all segments. A magnet at the bottom of the cone. leeve with internal threads . Rod with external threads . Sharp tip Magnet, which acts as a handle . he imprint of the cone (112) (ingot). The imprint of the model (110). Air duct. Stand. Magnet, forms the foundation of the stand. Rod. ylinder. Rod. Ball j oint coupling . Attachment for grain tweezer. Grain tweezer. Segment divider. Thin strap that runs around the bottle in just under 2 turns. Hose clamp that screws to the strap. Hobs for the hose clamps (203). asting bottle with bottle walls 205a for the segments.

Internal adhesive element. Numbering of the bottle walls. Arrow indicating in which direction the numbering should increase. Segment consisting of the bottle walls 205a and compressed sand. The model to be casted. Thin plate, slightly larger than the hole in the center of the model (210). Screw, which reinforces the core in the hole on the model (210), so that it follows the cover. Loosely packed sand in the hole on the model (210), so that the screw (223) is held in place. Interface between the segments. Lid with the same shape as the segments form (a cylinder in this case), fastened over the bottom segments with a strap (227). Strap that holds the lid above the segment bottle. Sand compressed in the lid above the segment bottle. Tracks running along the inside of the lid to hold the sand inside. Can be covered with magnetic tape when casting with plaster, so that you can detach the plaster from the lid. Ingot in the lid (cone-shaped), which opens into the top of the model (210). Air duct opening onto the diagonally opposite side of the ingot (230). Air duct opening onto the underside of the model (210), directly below the air duct in the lid (231). Interface between lid and segments. Countersink. Segment divider. Thin strap that runs around the bottle in just under 2 turns. Hose clamp that tightens the strap (302). Hobs for the hose clamps. Casting bottle with bottle walls 305a for the segments. Internal adhesive element. Numbering of the bottle walls. Arrow indicating in which direction the numbering should increase. The segments fdled with compressed casting sand. The model to be casted. Ferromagnetic base plate with lines and in this case circles, which guide the segments towards the center of the bottle. 31 la. Number markings on the base plate, corresponding to those on the bottle walls (307) A magnet, which acts as a handle . Lid with the same shape as the segments form (a cylinder in this case). Strap that holds the lid above the segment bottle. Sand compressed in the lid above the segment bottle. Strong (> 50 N) magnet, forms the foundation of the stand, which can thus be placed anywhere on the plate (311). Rod where a pierced cylinder (353a) can run around and adjust the height by fasten it around the rod with a screw. Cylinders with a ball joint attached to one base of the cylinder and with a hole drilled in the cylinder, parallel to its base. Rod with a hinge ball at one end and with a cylinder (353b) that runs around and can be attached to the rod. Ball joints, consisting of two parallel plates that are clamped around the joint balls to secure them. Attachment for a grain tweezer (357) with a hinge ball at one end. Grain tweezer that can be easily clamped and loosened around the model (310). Imprint of the model (310) in the sand. Air duct. Ingot