US2191687A - Sand mold making - Google Patents

Description

' Feb. 27, 1940. J. SKATES awn MOLD MAKING Filed Dec. 21, 1938 4 Sheets-Sheet 1 #29 Fig. 9. g

J. .11. Ska-fies Feb. 27, 1940. J. L. SKATES SAND MOLD MAKING 4 Sheets-Sheet 2 Filed Dec. 21, 1938 El El WITNESS r Fgb. 27, 1940. J. L. SKATES SAND MOLD MAKING Filed nee. 21. 1938 llllL www u mwwi Fig. 4.,

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J. L. Ska-fee Patented Feb. 27, 11940 UNITED stares PATENT OFFICE 2,191,687 SAND MOLD MAKING Jacob L. Skates, Bessemer, Ala. Application December 21, 1938, Serial'No. 247,127

6 Claims.

Heretofore, in the casting of metal pipe and the like with the aid of sand molds, it has been customary to prepare the molds by hand, necessarily giving slow production and making it virtually impossible for manufacturers using the sand mold process to compete with-others using more rapid methods. Moreover, when the molding sand is hand-packed in the drag and cope, it has been impossible to obtain uniform packing of the sand. Non-uniform packing of course means a non-uniform mold, producing pipe of varying thickness and usually thicker than required, and not infrequently causing disruption of the mold while pouring.

It has heretofore been virtually impossible to so pack the sand which forms the usual coreholding prints, as to unyieldingly support the core in the completed mold, the result being that said core often rises when pouring, producing the ends of the core and said seats or notches,

under which circumstances the prints in the sand mold (formed by'the end portions of'the pattern) must alone be relied'upon to hold the core centered. With hand-packed sand, these prints often fail tol properly perform this function resulting in a faulty product.

It is customary to provide the drag or cope with vertical partitions spaced above the pattern for holding the packed sand in place in the com- 5 pleted mold and it has been virtually impossible to properly pack the sand between the inner edges of these partitions and the pattern, the resultjbeing that the sand between said inner edges Oif said partitions and the core, is outwardly forced by the molten metal when pouring, causing the metal to form unnecessary and undesired circumferential ridges on the pipe.

It is'to overcome all of the drawbacks above enumerated and place the sand mold process on equal footing with other processes, that the presentinvention has been produced.

With the above in View, the invention resides in the novel subject matter hereinafter described and claimed, description being accomplished by reference to the accompanying drawings.

Figure l is an end elevation of one form of machine constructed in accordance with the invention. v

Fig. 2 is a front elevation, partly in section, of the machine shown in Fig. 1.

pipe of greater thickness at the lower side than Fig. 3 is a vertical longitudinal sectional view substantially on line 3-3 of Fig. 1.

Fig. 4 is 'a view-similar to Fig. 3 but showing the manner in which the first ram packs the sand in the drag or cope causing the pattern to 5 form the desired molding impression and the core-holding prints.

Figs. 5 and 6 are vertical transverse sections on lines 5-5 and 6-6 of Figs. 3 and 4 respectively.

Fig. 7 is a. view similar to Fig. 6 but showing the manner in which the second ramcompletes the sand packing operation.

Fig. 8 is a fragmentary longitudinal sectional view of the completed mold showing the manner in which the prints unyieldinglysupport the core even if the ends thereof cannot tightly engage seats or notches at the ends of the flask.

Fig. 9 is a fragmentary top plan View showing an arrangement which may be used in making a mold for a plurality of pipes.

Fig. 10 is a diagram showing the manner in which a turntablemay be advantageously used in making the molds. s

Fig. 11 is a detail transverse section showing a different formation for the ram H3.

The description will first explain the funda mental structural features of any machine constructed in accordance with the invention, will thenexplain the process carried out with the aid of said fundamentals, and will finally give examples of different ways in which said fundamentals may be associated with other elements.

Reference is first made more particularly to Figs. 3 to 7 inclusive. In these views, 1 i denotes a suitable bed from which a. horizontally elongated semicylindrical pattern l2 projects upwardly, saidpattern having a main portion extending from the'line l3 to the line M- 'to form a molding impression in the sand, and having 40 end portions l5 and I6 to form the usual prints. in the sand, to later support the core (shown at I! in Fig. 8). Operatively related with the bed II is a drag or cope 18 in which to pack molding sand to "provide asand mold having the desired molding impression and prints. Re-

ceivable in the drag or cope I8, isa ram l9, said ram having an. arched formation 20 extending longitudinally of its lower side to pack the sand upon the pattern I2, and also having horizontal lower faces 2| at the lower terminals of said arched formation, to pack the sand upon. the bed H. The end portions 22 of the arched formation 20 which pack the sand upon the end portions 15 and i of the pattern l2, to produce the core-holding prints are, in any position of the ram 19, spaced closer to said portions l5 and 16 than the intermediate portion of said arched formation 29 is spaced from the cooperating portion of the pattern I2, as will be seen by comparing the distances A and A of Fig. 3 with the distance B. Thus, when the ram I9 is lowered to press the sand, the sand 23 which forms the core-holding prints, will be pressed much harder than the sand 24 which forms the molding impression. It is thus insured that these prints in the complete mold (see Fig. 8) will unyieldingly hold the core I! centered within the molding impression 24, even if the ends of said core be spaced from the edges of the seats or notches 25 in the ends of the cope or drag, which spacing is customary. The core is thus held against shifting during pouring and consequently a pipe cannot be produced thicker at its lower side than at its upper, as now often occurs. The core I? is shown as constructed from a metal arbor 26 covered with molding sand 21. The sand 27 ordinarily extends to the so-called iron prints 28 at both ends of the arbor 26 which prints snugly engage the sand prints 23 and hold the core centered.

It is preferable that the drag or cope I8 be provided with vertical transverse partitions 29 to better hold the packed sand in place, said partitions having arched lower edge portions 3|) which extend over and are spaced upwardly from the pattern I2, and also having horizontal lower edge portions 3! spaced upwardly from. the bed I i. To inwardly crowd the sand under the edge portions 30 and 3! as the ram l9 descends, I provide said ram with beveled formations 32 at opposite sides of the slots 33 which receive the partitions 29, said beveled portions 32 being disposed at the juncture of the opposite walls of the slots with the arched formation 26 of the ram and being preferably in the form of beveled ridges projecting downwardly from said formation 20 and from the horizontal portions 2| of the ram. The beveled faces of the ridges or the like 32 diverge downwardly and they thus tightly crowd the sand under the partitions 29 as seen in Fig. 4, giving to this sand a compaction or density equal to the'rest of the sand which is to form the molding impression. Thus, in the completed mold, there are no relatively weak portions at the inner edges of the partitions 29 and consequently the molten metal will not crowd the sand outwardly and form undesirable circumferential ridges upon the pipe.

After the ram I9 is operated, more sand is added to the drag or cope and a second ram 35 having a fiat lower side 36, is used to compress this sand, both the first fill and the second fill being compressed with the same amount of power.

Preferably, the bed II is in the form of an ordinary pipe jack having means for raising and lowering the pattern l2, and for illustrative purposes, I have shown the pattern supports in the form of earns 31 on rock shafts 38, said rock shafts being connected by a conventional link and lever mechanism 39, 40 so that the cams or the like may be operated to hold the pattern I2 operatively positioned, and to drop said pattern'after the sand packing operation has been completed. The pipe jack is shown as provided with the usual stripping plates 4| In order to form the necessary pour holes in the mold, conventional pins and gates (not shown) will of course be used at desired points, and any suitable number may be employed. The pattern which I have disclosed is provided with lugs 43 near its ends to form lugs on the ends of the pipe, to be bolted together, and suitable provision forming no part of the present invention, can of course be provided whereby the pipe lugs are cast with the required bolt holes therethrough. It may also be explained that the pattern i2 which has been shown, is intended to form a pipe having a male end and a female end, both of which are to be machined after casting, but it will be understood that I am not restricted to forming pipes of this nature.

In carrying out the process, the drag or cope I8 is operatively related with the bed H and the pattern i2, and a suitable quantity of sand is discharged into said drag or cope and substantially leveled. The ram IQ is then brought down under power to solidly pack the sand upon the pattern l2 and upon the bed H at opposite sides of said pattern. Due to the fact that the surface of the sand is about level when it is engaged by the ram I 9, the sand will be packed more densely by the ram surfaces 2! than by the arched formation 20, which is proper, for the sand packed by the surfaces 2i must abut the sand of the other mold section and should be packed very tightly, whereas the sand around the pattern i2 should be densely packed, but not packed sufficiently tight to prevent air and gases from escaping during the molding of the pipe. It will also be observed that the sand pressing operation causes the ram surfaces 22 to compress the sand for the prints 23, much more densely than the sand 24 which forms the molding impression, insuring that said prints shall unyieldingly hold the core I! centered in the completed mold, as seen in Fig. 8.

Further attention is drawn to the fact that simultaneously with the compaction produced by the ram surfaces 20, 22 and 21, the bevel means 32 effects thorough packing of the sand under the partitions 29, preventing weaknesses which would otherwise allow the formation of circumferential ridges on the pipe.

After the packing operation is performed by the ram I9, more sand is added and this sand is packed with equal pressure by-means of the second ram 35, as seen in Fig. 7.

After the drag or cope is completely filled and completely packed, it and the pattern l2 are relatively disassembled, thisbeing done in the present instance, by dropping said pattern. The filled drag or cope is then in readiness for use to form half of a sand mold, as will be clear from Fig. 8. Assuming that the cope is filled and packed as explained, the drag may be prepared in the same Way either with the same machine or with a separate machine, preferably the latter, the drag and cope being then properly assembled with the core I! to form the complete mold shown in Fig. 8. The prints 23 unyieldingly hold the core centered, irrespective of any holding action which may or may not be performed by the seats or notches 25, and as the sand is packed throughout to the proper density, a perfect mold is provided which will produce perfect pipe.

In Fig. 9, I have shown what may be termed a twin cope or drag IB for holding twopatterns 12 said drag or cope having the partitions 29 For use with the assemblage shown by this view, one ram is of course provided having a twin formation shaped to perform the first sand pressing operation, and another ram is used to perform the final pressing operation.

The two rams I9 and 35 above described, or

the two rams cooperable with the structure shown in Fig. 9, may be embodied in one press if desired,

as seen in Figs. 1 and 2 or in two different presses as diagrammatically illustrated in Fig. 10. Similarlyany suitable means may be used to move the drag or cope from a firstfilling position to a first ramming position, and then to a second filling position, then to a second ramming position, and finally to a take-off position. For examples, Figs. 1 and2 disclose a car and track arrangement for moving the. drag or cope as required, and Fig. 10 diagrammatically illustrates a turntable for this purpose.

In Figs. 1 and 2, the rams l5 and 35 are formed by opposite sides of a single head 45, said head having trunnions 46 upon which it may be turned to bring either of said rams into position for use,

hand wheels or the like 41 being provided on said trunnions. These trunnions pass through vertical slots 48 in a pair of arms 49 which are secured toand project downwardly from a ram head 59. Suitableoperating means such as hydraulic cylinders 5|, pistons 52 and piston rods 53. connecting said pistons with the head 50, are employed for depressing'the latter with required pressure. Normally the head 45 is sufliciently below the head 50 to prevent the latter from interfering with turning of the former upon the trun nions 46, but when either the ram. H3 or the ram 35 comes down upon the sand, its movement is limited, whereupon the ram head 50 lowers into contact. with whichever ram is then uppermost,

whereupon the downward movement of said head 5.8 will depress the head 45 to perform the sand packing operation. After the first operation is carried out with the ram l8, the head 45. is inverted and a second press is effected with the ram 35. I i

Suitable provisionis made to hold the head 45 against accidental turning. For illustrative purposes, two pins 54 are shown slidably carried by, one of the hand wheels 41 to engage one of the slots 43, one pin being used when the head 45 is in one position and the other pin when said head occupies its other position.

In Figs. 1 and 2, the bed H is provided with flanged wheels resting upon a suitable track 56, "and said bed is operatively connected by means of a rod 51 and piston 58, with a hydraulic cylinder or the like 59, permitting shifting of the, drag or cope l8 as required. It is preferable to provide a sand hopper and a conveyor SI for carrying sand thereto, and to provide an appropriate means 52 for controlling the discharge of sand to said hopper. When the drag or fiask I8 is positioned under this hopper, the means 52 is operated to discharge the first quantity of sand into said drag or cope, whereupon this drag or [cope is moved to a position under the ram head 45. The ram I9 is now used to perform the first sand packing. operation. Thenthe drag or a turntable 53 to support the drags or copes I 8,

said turntable being operated in any suitable way to move any drag or cope from an initial or put onfiposition to a first fill position, then to a first ram position, then to a second fill position, next to a second ramposition and finally to a' take off position.

The extent to which the drag or cope is filled with more sand, the level is approximately threefourths of anv inch above the upper edge of the drag oncope, and for the final compaction, this level is forced down even with said upperedge. Both of the sand-packing operations, regardless of the exact construction of the press, are prefcarried out with the same pressure. This maybe insured by providing a pressure relief valve 5d in the line 55 which supplies the hy- 1 clraulic fluid for operating'the ram. Whenqthe ressure on the ram reaches the predetermined amount, the valve 64 will open and permit no pressure on said ram in excess of that for which said valve is set. A pressure gauge '55 is of course provided for obvious reasons. While a hydraulic fluid is preferably employed to force the pistons fifldownwardly, air under pressure may be admitted under said pistons to again raise the press,

a suitable air line 51 being shown for this pur- I pose. Any appropriate provision may, of course, I

be'made for handling the exhaust of air from the lower end of the cylinders when the pistons are being forced down by the hydraulic fluid, and for handling the exhaust of. hydraulicifiuid when said pistons are being forced upwardly by the compressed air. Moreoven'whfle hydraulic pressure, air pressure, or both are preferable in operating-the press or presses, it will be obvious that other operating provision could be made if desired. i "i From the foregoing, it will be seen that novel and advantageous provision has been made for carrying out the object of the invention and while preferences have been disclosed, variations may, of course, be made within the scope of the invention as claimed. 3

I claim:

1. In a machine for making a pipe or, similar mold, said machine'having a bed-supported pattern provided with 'end portions to form coreholding prints; a ram for packing molding sand upon said pattern and its supporting bed, the lower side of said ram being provided with a longitudinally extending transversely arched formation to pack the sand upon said pattern,-the end portions, of said arched formation. which pack the sand upon said print-forming end portions of said pattern being spaced, in all positions of the ram, a shorter distance above saidprintforming end portionsof the patternthan the intermediate portion of said arched formationis spaced above the intermediate portion of said pattern, insuringpacking of the print-forming sand more tightly than that which forms the molding impression,'causing the prints to un-' yieldingly hold the extremities of the core in the 1 completed mold.

2. In a mold making machine having a bedsupported pattern, and a drag or cope provided with spaced verticalpartitions above said pattern; a ram receivable in said" drag or cope and having a working face to pack molding s and on said. pattern and its supporting bed, said ram hav--' ing downwardly open vertical slotsyto receive said partitions, said ram being provided with beveled portions at the juncture of said working face with the side walls of said slots, the beveled portions at opposite sides of each slot being disposed in downwardly diverging relation with each other to inwardly crowd and pack the sand under said partitions, obviating low density zones in the mold under said partitions. i

3. In a mold making machine having a bedsupported pattern, and a drag or cope provided with vertical partitions above said pattern; a ram receivable in said drag or cope and having a working face to pack molding sand on said pattern and its supporting bed, said ram having downwardly open vertical slots to receive said partitions, said ram being provided With downwardly projecting ribs at the juncture of said working face with the side walls of said slots, the inner opposed faces of the ribs at opposite sides of any slot being disposed in downwardly diverging relation with each other to inwardly crowd and pack the sand under said partitions, obviating low density zones in the mold under said partitions.

4. In a press, a ram having different working faces for performing different operations, said ram being provided with trunnions upon which it may be turned to position any of said working faces downwardly for use, a presser head normally spaced above said ram to permit turning of-the latter upon said trunnions but movable downwardly onto said ram to depress the latter, means for suspending said ram from said presser head without prohibiting the necessary relative vertical movements of said ram and presser head, said suspending means having portions for preventing lateral movement of said ram with respect to said presser head, and releasable means for holding said ram against turning upon said trunnions during the relative vertical movements of said ram and presser head.

5. In a press, a ram having different working faces for performing different operationsysaid ram being provided with trunnions upon which it may be turned to position any ofsaid working faces downwardly for use, a presser head normally spaced above said ram to permit turning of the latter upon said trunnions but movable downwardly onto said ram to depress the latter, rigid suspending arms for said ram secured to and projecting downwardly from said presser head, said arms having vertical slots in which said trunnions are received, to allow the. necessary relative vertical movements of said presser head relative to said ram and to prevent lateral movement of said ram with respect to said presser head, and releasable means for holding said ram against turning upon said trunnions during the relative vertical movements of said ram and presser head.

6. In apress, a ram having different working faces for performing diiferent operations, said ram being provided with trunnions upon which it may be turned to position any of said working faces downwardly for use, a presser head normally spaced above said ram to permit turning of the iatter upon said trunnions but movable downwardly onto said'ram to depress the latter, l

rigid suspendingarms 'for said ram secured to and projecting downwardly from said presser head, said arms having vertical slots in which said trunnions are received, to allow the necessary relative vertical movements of said presser head relative to said ram and to prevent lateral movement of said ram with respect to said presser head, and latch means mounted on said trunnions and engagealole with at least one of said slots to hold said ram against turning upon said trunnions during the relative vertical movements of said ram and presser head.

JACOB L. SKATES.

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