US2512871A - Core blowing machine - Google Patents

Description

June 27, 1950 o. OSTERMANN ETAL CORE BLOWING MACHINE 2 Sheets-Sheet 1 Filed March 29, 1944 June 27, 1950 o. OSTERMANN ETAL CORE BLOWING MACHINE 2 Sheets-Sheet 2 Filed March 29, 1944' &\

ings. propulsion principle rather than sweeping: the

Patented June 27, 1950 PATENT OFFICE Walled :Lake; Michz, assign'ors: to Redford Iron: & Equipment-.Companmbetroit, Michi, a cor.-

. poration. of Michigan Application March29, 1944,.S'erial No. 5283308 4 Claims. 1 This inventionrelates to aimethod-and apparams for blowingcores:

Many typesof core blowing machines havebeen proposed. in the'prior' patented art and. core blowing machines are now in extensive use'in industry. These machines are ratherlarge machines that involve the use of magazines forzcontaining sand and distributing heads. for distributing the sand to the cavities of the core mold OItibOXi- These core blowing machines are subject to certain shortcomings which it is theobiect ofour invention. to overcome. .One of these'shortcomingsis-the sand distributing: head has to be provided' with different bottom plates for difierent style core b'oxes. These plates have tobe changed each time a different style core boxis blown; and time consuming adjustment" 0t thermachine may have tobe made: toaccommOdata core boxes of difierent heights.

Another serious handicap has beenthat if the moisture contentofithesand is too high, the apparatus will not work touform proper cores. Only sand'orvery low moisture content can be used in blowing intricate cores. For instance, iflth'e sand'has a moisture content of say more than two per cent, the-conventional type of core blowerwill not eflecti-velycarrythe sand into the core box; Webelievethis to be due to too. greatdiffiusion of the air blast which is allowed to expand andlose its propulsive effect particularly in core blowing machines that have theusual downwardly flaring type-of corewblow inghead. .We do noth-ave to soicloselycontrol the moisture contentof the sandused inablowing with our'machine. Sand with a moisture content offrom two toefive per cent can beus'ed without difficulties.

We propose to use a cartridgewhich' contains for discharge only thenecessaryramount of sand for eachcorebox; There is at the lower end an enlargement or a base for spannin the openings into the corebox. In this base is packed a mass of sandwhich will resist difiusion of the air streams. This concentrates the airand causes the same to pack the sand tightly" in this con:- stricted chamber used'to span thecore'box open- The air blasthere operates on the piston sand along in the wake of the air blast as isthe principle of operation, We believe, of core blowers of the prior art. Hence, in our new and novel. type of core blower the moisture content of the sand is not. as critical as is the case with? conventional core blowers. Sand with more than two per cent and. up to five per cent or more; of moisture canbe successfullyused.

v 2 The machine is a* small, simple, and handoperated machineth-at maybe set on a benchand operated with a minimum of skill. Nomagazines and sand distributingreservoirs are needed, with their valves; controls, etc. There is simply a hand-operated air reservoir which can he raised lowered with one handy whilethe outlet valve imthe. reservoir is opened with the other hand to allowith'e air blast to pass rout. The sandcartridgeian-d'the core box openingapanning base is ametaiishell', that can be made: of welded metal partsorof a casting Inste'adofther usual raising of the core box support mechanically or f by fluid pressure, our machine provides axstationary core box support whi'ehimay rest directly onthe work bench. The relative: movement to" bring the air. supply, the

sand supply" and the. core box' together is secured by simply 1 raising and lowering. therair reservoir by means of achand operation; transmitted through a" pinion sand mack? or any other convenient mechanicardevice. The-sand container or cantridge isplunged ordipped into a pile of sand: on; the bench: each time to get a. charge or refilh Thiswachieves simplicity i and arsaving in supplyingand handling: the coresand.

Reterring to thedrawings:

Fig. 1 is a- Side:].-Vati0lil of the machine show- .ll'lggthe sand container and the core' box partly broken away;

2 is :a view showingrthe air reservoir clamped on thesand container 7 or cartridge. Fig. 3-is-1a iront elevationof the machine. Fig.4 .isr'a sectionron: the line fil -4 of Fig. 1. Fig, 5 israrsection on the line 5-5'of Fig. 2. Fig, fi -isa perspectivesof thesand cartridge.

l- -desisnates th'e platform at the base of the machine; 2. :the upright post on which the arm 3 may beadjusted by awboltkwhich passes through The arm carries a sleeve 5 i at the fiwhich hasia rack 1 secured .to the'side. This meshes with the pinion 8 onther shaft 9 which maybe rocked bymeans of thezcl'ank it A drag typecofwdetent l I bears against the: circular head l2nwhich isnprovi-ded with sockets i3" for the insertion of the-end of thecrankil E...

Cylinder Storms aneair reservoir with avvalve M at the bottom. This valve has a pilotisleeve 14 for guidingit in the opening in the interiorly threaded cap IT at the end of the cylinder. The valve has. aflange l8kwith perforationsplfis The flange: is: arranged to. seat on the gasket 2i at the lowerend ofithe cylinder and .isheldi in Jth-iSJDO- sition by the air pressure and also by: the helical 3 spring 2!. pressing down on the lever 22, this allows the air blast to pass through the openings l9 and the openings 23. A valve stem 24 connects the valve with the lever 22. This specific type of valve and valve operating mechanism, of course, is not at all essential,- but it is found to be an'efiicacious one. i

The core box is designated C and is provided with several core cavities 2'5 with openings 26 leading into the cavities.

The usual core blowing machine has a rather forming a seal therewith. Usually each time the type of core boxis changed a heavy plate has to be detached from the bottom of the sand dis- When the valve is raised by means of 1 tween the air reservoir and the core box. Then another blast of air is directed into the cartridge to clear the charge contained in the upper chargecontaining chamber.

We find that a suitable diameter for the tubu- 'sand in the base of the cartridge as this forms a protective plug ofv solid sand to protect the contents of the core box and the core box against the blast of high pressure air. If a suitable protecting' plug is not afi'orded the air blows through the bottom of the sand reservoir or cartridge and tributing head and exchanged for another plate 7 with openings suitably located to register with the openings in the new type of core box. Furthermore, the machine parts may have to be rearranged or adjusted to take a difierently shaped core box of perhaps different height.

To obviate this we propose to use a small cartridge containing sand and provide it on its lower end with a laterally extending base of restricted dimensions for concentrating the air blast to pack thev sand in the base so that it will be propelled piston-like into the openings in the cavities of the core box. The cartridge proper is designated 21. The restricted base and core-opening-spanner is designated 28. The bottom of the base has open ings 29 for registering with the openings 26 in the core box. The operator presses down on the crank in which causes the cylinder 6 to descend on the top of the cartridge 21 where the sealing ring 3! forms an air seal. Thereupon the operator presses down on the lever 22 with the other hand. This opens the air valve. The charge of sand 'in the cartridge is carried down into the base 28 and in this restricted chamber the air, instead of being difiused as in previous designs of core blowing machines, is concentrated and serves to pack the sand in the base of the cartridge.

and into the openings in the core boX. Sand is left packed in the enlarged base after the blow, as shown in Fig. 2. The air passes out through screened vents in the core box which are not here shown as they are well known in the art.

We find in practice that the size of the cylindrical or charge-containing portion of the cartridge need be just enough to contain one charge of sand for the core box. Of course, it can be made larger, but we believe it is better to make it substantially of the volume of the core box cavities and openings. If it is made smaller'than the volume of the core box some of the sand in the base is carried into the core box'and the machine loses its effectiveness. I

In place of charging hoppers, which have to travel back and forth to large sand reservoirs which in turn have to be re-supplied at regular intervals by elevating the sand to the top of the machine, all that our machine requires is a pile of loose sand on the bench. At the end of each blow the attendant raises the-air reservoir. He

' refills the cartridge by simply plunging it into the sand pile at his side. Another core box is placed on the platform, the reloaded cartridge is inserted between the reservoir and the core box and again the cartridge is pinched in air-sealed relation beforms craters in the sand of the core box. This is most undesirable.

This interchangeable cartridge can blow almost any type, size or shape of core box on the machine without changing the machine set up. One simply picks up the correct cartridge for the core box and inserts it between the new core box and the air reservoir. With machines now in use, this usually requires a change of the core-box-openings-spanning plate on the bottom of the sand hopper, to make the openings register and also it may entail some rather tedious adjustments to get the parts to the'proper height to handle the new core box. i

. This machine is particularly useful in packing core boxes for intricate cores. That is very often done by hand. On the bench we find that one operator can use this simple machine to make four times asmany cores as he can when he has to pack the core boxes by hand.

' tion would be of T shape.

It will be noted, in taking a side elevational view of the cartridge, shown in Figs. 1 and 2, that the general contour of the cartridge is that of an inverted T. Or if one were to slice down through the cartridge at the center in a plane longitudinally of the base, or what we term longitudinally of the cartridge, the longitudinal sec- We have given this description for the purpose of using the same in the claims in order to more particularly describe the cartridge and distinguish from the prior art.

It will be understood in the claims, when referring to the core box, that the core box may include one or several cores. The drawings show the core box having several cores. On the other hand, the several core boxes could be abutted, one against the other, and held in this position for one blow with one cartridge, so we want it understood the claims cover these several things.

. What we claim is:

1. A sand holding cartridge for interposition between an air discharge reservoir having a discharge port controlled by an air valve and a core box and supporting platform of a machine for blowing cores, said cartridge comprising a charge holding body portion of substantially uniform cross section and having a capacity to contain substantially only a charge for one core box blow, and a hollow sand-distributing base portion expanding the cartridge abruptly at the end of the body portion and serving to span the core box and blow holes therein, and having a limited thickness, the cartridge, when viewed in side elevation, or in longitudinal section, being of substantially inverted T shape, the body forming the upright bar of the T and the hollow base the cross bar of the T.

2. A sand holding cartridge for interposition between an air discharge reservoir having a discharge port controlled by an air valve and a core box and supporting platform of a machine for blowing cores, said cartridge comprising a chargeholding columnar body portion and having a capacity to contain substantially only a charge for one core box blow, and a hollow sand-distributing base portion expanding the cartridge abruptly at the end of the body portion and serving to span the core box and blow holes therein, said base portion having in its bottom blow holes to register with the blow holes in the core box and having a limited thickness, the cartridge, when viewed in side elevation, or in longitudinal section, being of substantially inverted T shape, the body forming the upright bar of the T and the hollow base the cross bar of the T, with the base of the cartridge or the cross bar of the T of substantially less thickness than the body of the cartridge or upright of the T.

3. A machine for charging a core box with sand, having in combination a platform for supporting the core box, an air reservoir, an upright and laterally extending frame member for supporting the reservoir above the platform to allow one relative movement with respect to the other, means for giving the reservoir and the platform relative movement, and a portable cartridge separate from other parts of the machine and adapted after each operation to be removed from the machine and manually loaded and then replaced between the reservoir and the core box on the platform and pinched between the same when relative movement occurs between the two, said cartridge having a hollow upright column dimensioned to contain substantially only one charge for the requirements of one blow of core or cores and having a laterally extended shallow base for spanning all the core box openings and to provide openings in the bottom of the base to register with the core box openings, said base having little depth to concentrate the air pressure and leave after a blow a light-weight protective plug of sand in the base which will protect the core box contents from direct contact with the high pressure air and will not materially interfere with ease of handling the cartridge in removing it from the machine, reloading it and replacing it in the machine. I

4. A bench machine for charging a core box with sand, having in combination a platform which can be set on a work bench for supporting the core box, an air reservoir, an upright member supported on one side of the platform and having a laterally extending arm for supporting the air reservoir for relative movement with respect to the platform, means for giving the reservoir relative movement with respect to the platform, and a removable cartridge interposed between the reservoir and the core box resting on the platform and pinched between them when relative movement occurs between the two, the said cartridge comprising a hollow upright columnar portion dimensioned to contain substantially only one charge of sand for the core box and a laterally extending shallow base containing surplus sand that is packed in the base, the said base acting as a core-box-opening-spanner and having little depth relative to its other dimensions to concentrate the pressure on the sand delivered to the core box openings and retain a light load of sand in the base to protect the core box contents from the high pressure air.

OTTO OSTERMANN.

ERNST BLENDIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS- Number Name Date 1,447,376 Campbell Mar. 6, 1923 1,594,598 Campbell Aug. 3, 1926 1,703,708 Candler Feb. 26, 1929 1,808,630 Brown June 2, 1931 1,927,571 Meyer Sept. 19, 1933 1,950,632 Romph Mar. 13, 1934 1,994,028 Rolfi Mar. 12, 1935 OTHER REFERENCES Pages 203 and 206, Modern Core Practices and

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