US2514952A

US2514952A - Mold

Info

Publication number: US2514952A
Application number: US696518A
Authority: US
Inventors: Karl S Howard
Original assignee: General Steel Castings Corp
Current assignee: General Steel Castings Corp
Priority date: 1946-09-12
Filing date: 1946-09-12
Publication date: 1950-07-11
Anticipated expiration: 1967-07-11

Description

July 11, 1950 n K.-s. HOWARD 2,514,952

' MOLD Filed Sept. l2. 1946 5 Sheets-Sheet 1 Flai.

o .E 2o

/A/ VEA/T25@ KARL. S. H cz-wA RD K.- S. HOWARD July 11, 195o MOLD 3 Sheets-Sheet 2 /A/VE/UTOR KARL S. HOWARD Filed sept 12, 194s July ll, 1950 l K. s. How/ARD 2,514,952l

` MOLD Filedsept. 12. 194e s sheets-sheet s KARL. S, HOWARD rns /e ngi) /QTTOR/Us Patented July 11, 1950 MOLD Karl S. Howard, Haverford, Pa., assigner to General Steel Castings Corporation, Granite'City, Ill., a corporation of Delaware Application September 12, 1946, Serial No. 696,518

The invention relates to molds and particularly to 'molds `for casting elongated objects, such as large engine crank shafts.

`The main object of the invention is to produce .large elongated castings of high quality and -thereto as possible without interfering with the ,strength of the mold. -A plurality of short sprues 'of equal length and cross sectional area lead from the heads to the cavity. Referring more particularly to the casting of an engine crank shaft, each sprue leads directly to a main bearing formingfportion of the cavity and each head, with its sprues, is positioned at the side of the cavity opposite the associated crank pin forming por- Vtions to which that head` feeds molten metal and at least some of these crank pin forming portions are arranged symmetrically about a r plane passing through the axes of the associated head and the cavity. With this arrangement,

` the paths Aoi" flow from the heads to the associated crank pin forming portions of the cavity` are V'equal in length and shrinkage forces are sub- -stantially uniform throughout the cavity.

Other objects will be apparent to those skilled yin the art from the following description and ,accompanying drawings, in which:

`Figure l is a top View of a mold constructed 1 according to the invention.

Figure 2. is substantially a central vertical 1on- .gitudinal section through the mold, all of the J right hand side of the ligure and that part of the :t left hand side below the break line A-A being taken on the line 2 2 of FigureV 1, and the left :hand side or the ligure above the break line being taken on the line 20L- 2a of Figure l, except that for clearerillustration each crank arm and pin is shown as if the plane of the section passed through the arm center line and the pin axis and `was, projected yon the planevof the line 2-2 or Figure 3 is a transverse horizontal section taken approximately on lines 3--3 of Figures 2 and 6.

y. Figure 4 is a transverse horizontal section takenV approximately on' lines 4-4 of Figures Figure 15 is a transverse horizontal section 4taken approximately on lines 5--5 of Figures 2 and 8. l.

Figures 6, 7 and 3 are vertical longitudinal 'l sections taken approximately on. lines 6 6, l-f'! and 8-8 of Figures 3, 4 and 5, respectively,

2 The mold comprises a rectangular box-like housing having sides A, B, C and D of substantially equal size attached rigidly together by bolts B. The housing is attached to base E by bolts 5I. `Positioned within the housing are a series of baked sand sections I-22, inclusive, mounted one on top of the other, section l being at the bottom of the housing and section 22 being at the top. Each of the sections has one or more openings or depressions arranged so that when the sections are assembled in the housing, the openings and depressions form an elongated vertically disposed cavity 52 similar in shape to the crank shaft to be cast and provide gates, risers and sprues, as described in detail below, for feeding the metal to the crank shaft cavity.

The sections arevpositioned in one corner of the housing with two sides of each section adjacent sides A and B. Sand 51 is rammed between the other two sides of each section and sides C and D of the housing. To facilitate assembly of sections |22 'in the housing, side D preferably is constructedin two parts, Dl and D2. With lower part D2 assembled with the housing and with upper part Dl removed, sections I-I2 are inserted in the housing and sand 5l is rammed between sides C and D and the sections, preferably as the sections are installed. Upper part DI then is assembled with the housing and the remaining sections I3-22 are installed and sand 5l is applied between these sections and sides C and Das described above.

Sections I-22form an inlet gate 23 which is connected by a plain gate

S'l'and step gates

38 and 39 to a blind head 24 in sections l-S. Head 24 is connected by

sprues

21, 28 and 29 `to the crank shaft cavity at main bearings I b, 2b and 3b, respectively, and molten metal from head 24 iiows direct to these bearings and then through the associated crank arms to the corresponding crank pins la, 2aand 3a.

Inlet gate 23 is connected by step gates 40, 4|, 42 and 43 to,V a blind head 25 in sections 1-16. Head 25 is connected by

sprues

39, 3|, 32 and 33 to the crank shaft cavity at main bearings 4b, 5b, 6b and lb. Molten, metal from head 25 forms the latter-mentioned main bearings and

crank pins

4a, 5a, 6a and 1a and associated crank arms.

Inlet gate 23 is connected by step gates 44 and 45 to a blind head 26 in sections l5-20. Head 26 is connected by sprues 34 and 35 to the crank i shaft cavity at main bearings 8b and 9b. Molten 3 with the axis of the crank shaft, without unduly weakening the mold and are equidistant from the cavity axis, so that the sprues leading to the main bearings are all as short as possible and equal in length and the sprues are made equal in cross sectional area. Heads 24, 25 and 26 at the portions above the

sprues

29, 33 and 35, respectively, curve outwardly away from the cavity so as not to interfere with adjacent crank pin forming portions of the cavity supplied by the next higher head or with riser 46. Head 24 is positioned at the side of the cavity 52 directly opposite crank pin la (Fig. 3). Crank

pins

2a and 3a are symmetrically disposed about a plane passing through lthe axes of cavity 52 and head 24. Head 25 is positioned at the side of the cavity opposite crank pinsv 4a., 5a, Ba and 1a (Fig. 4) and directly opposite to head 24 though at a higher elevation.

Crank pins

4a and 5a and crank pins 6a and la are symmetrically disposed about a plane passing through the axis of cavity 52 and head 25. Head 26 is positioned at the side of cavity 52 opposite crank pins 2a and 9a (Figure 5) and isv spaced angularly from heads. 24 and 255 and is positioned at. a higher elevation than these heads..

angular spacing of. heads 2.4, 25 and 25 permits the use of disaligned vertical vents 54.

.55, and`55. vleading from heads 24, 2.5 and 26, re-

spectively, to the. atmosphere.

At the topy of each.

blind head

24, 25 and 2E is a triangular-shaped core 58 extending across the topv of the head to facilitate cleavage of the shrinking metal and prevent a vacuum forming in the head as the metal cools and shrinks.

f To cast the crank shaft, molten metal is poured through associated crank arms to crank pinsy 4a,

5a, 5a and la. Also molten metal flows from inlet gate 2t. through step gates 44 and 45 into head 26 and thence through sprues 34. and 35 into the crankshaft cavity to bearings 8b .and .9b and then through associated crank arms and to crank pins 3a, 9a, and bearing lllb. As additional metal is fed into. gate, 23, themetal rises in the crank shaft cavity into riser 45.. As the. metal cools and shrinks, heads 24, 25, 25. and riser 46 supply metal to the crank shaft. cavity to. prevent formation of airpockets in the crank shaft casting.

A mold of the kind described produces large elongated castings of high quality and accuracy and the shrinkage due to lcooling is uniform throughout the castings.

Thel details of the above-described .structure .may be varied from those shown without departing from the spirit of the invention and the exclusive use of those modifications coming within the scope of the claims is contemplated.

What is claimed is: .1.. A mold .for casting a crank shaft having alignedl main bearings and onset crank pins, comprising contiguous mold sections defining a metalreceiving mold cavity corresponding in shape to Ythe crank shaft to be cast with the longitudinal axis of the cavity upright, and a plurality of feeding heads equidistant from the cavity axis and each having. sprues arranged to feed metal to said cavity through selected main bearing portions of the cavity, said feeding heads being positioned at different elevations and being spaced from each other angularly about the cavity axis.

2. A mold for casting a crank shaft having aligned main bearings and offset crank pins, -comprising contiguous mold sections defining a metalreceiving mold cavity corresponding in shape to the crank shaft to be cast with the longitudinal axis. of the cavity upright, and a plurality of feeding heads having sprues for feeding metal to said cavity, said feeding heads being spaced from each other angularly about the cavity axis and each of said feeding heads being positioned on the side of the cavity axis opposite to its associated crank pin portions of the cavity.

3. A mold for casting a crank shaft having main bearings, crank arms and pins, comprising contiguous sections defining a mold cavity corresponding in shape to the crank shaft to be cast with the longitudinal axis of the cavity upright, and a plurality of feeding heads having'sprues to feed molten metal through selected main bearing portions of' the cavityl to the crank arm and pin portions of the cavity, said feeding heads being substantially equidistant from the cavity axis and spaced from each other angularly about the cavity axis and said feeding heads being positioned so that the associated crank pin portions of the cavity are symmetricallyv disposed about a planeV passing through the axes of the cavity and the associated feeding head.

4. A mold for casting a crank shaft, comprising contiguous mold sections dening a, metal receiving cavity corresponding in shape to the crank shaft to be cast with the longitudinal axis of the cavity upright, a plurality of feeding heads having sprues for feeding metal to said cavity, said feeding heads being positioned at different elevations and being spaced from each other angularly about the cavity axis, and an inlet gate corresponding in 'length to the crank shaft cavity and having a plurality of connecting gates for feeding molten metal to the feeding heads'.

5. A mold for casting a crank shaft having aligned main bearings and offset crank pins, comprising contiguous mold sections defining an inlet gate extending substantially the full depth of the mold, a plurality of feeding heads positioned at different elevations and spaced from one another, a plurality of step gates connecting said feeding heads to said inlet gate, a metal receiving mold cavity corresponding in .shape to the crank shaft to be cast and positioned with its axis upright .and equidistant from said feeding heads, and a plurality of sprues all connecting said feeding heads to different main bearing portions of the cavity.

KARL S. HOWARD.

REFERENCE S CITED The following references are of" record in the file of this patent:

UNITED) STATES PATENTS Number Name Date 1,992,677 Sorensen Feb. 26, 1935 2,014,224 Campbell Sept. 10, 1&935 2,095,707 Campbell Oct. 26, 1937 2,247,777 Hagemeyer July 1, 1941 2,303,608 Campbell Dec. 1, 1942 OTHER REFERENCES Modern Foundry Practice by Howard, page 229,