US1717325A

US1717325A - Method of and means for making reenforced cores of molds

Info

Publication number: US1717325A
Application number: US23812A
Authority: US
Inventors: Daniel J Ryan
Original assignee: Cleveland Trust Co
Current assignee: Cleveland Trust Co
Priority date: 1925-04-17
Filing date: 1925-04-17
Publication date: 1929-06-11
Anticipated expiration: 1946-06-11

Description

June 11, 1929. D; J. RYAN 1,717.325

METHOD OF AND MEANS FOR MAKING REENFORCED CORES OF MOLDS Filed April 17, 1912s 4 Sheets-Sheet -1 June 11, 1929. D, J, YAN 1,717,325

METHOD OF AND MEANS FOR MAKING REENFORCED CORES 0F MOLDS Filed A rii 17, 1925 I 4 Sheets-Sheet 2 (Nut-wrap W -W 4 Sheets-She et C5 D. J. RYAN Filed April 17, 1925 METHOD OF AND MEANS FOR MAKING REENFORCED GORES OF MOLDS June 11, 1929.

v June 11, 1929. D. .1. RYAN 1,717,325

METHOD OF AND MEANS FOR MAKING REENFORCED CORES OF MOLDS Filed April 17, 1925 4 Sheets-Sheet 4 ArmAwEy Patented June 11, 1929.

UNITED STATES PATENT OFFICE.

DANIEL 3'. RYAN, OF CLEVELAND, OHIO, ASSIGNOR TO THE CLEVELAND TRUST COM- PANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

METHOD OF AE'D MEANS FOR MAKING REENFORCED (JOKES OF MOLDS.

Application filed April 17, 1925. Serial No. 23,812.

. reenforced sand cores suitable for use in semipermanent molds, the invention being especially applicable to the production of cores for use in metallic molds suitable for the production of cup-shaped castings, such as engine pistons, formed of aluminum alloys or other light-weight metals. v

One of the principal objects of the present invention is to provide a rapid and economic method of making sand cores, and particularly green sand cores, of uniformly high quality having metallic reenforcements and adapted for use in semi-permanent molds. Anothnobject of the invention is the pro-- vision of improved apparatus adapted to carry out the core forming method last referred to.

Other objects more or less incidental or ancillary to the foregoing and the manner of attaining all of the various objects -will appear in the following description.

8 In carrying out my invention I provide a core box with an open topped cavity and suit ably constructed to permit removal of the core when formed. I also provide a metallic core-reenforcing structure comprising a. core print or arbor portion designed to engage the core box near the top ofits core cavity and another portion rigidly connected to the core I print portion and adapted to be embedded within the sand body of the core when formed. The core print portion is provided with one or more openings through which sand can be introduced into the cavity of the core box and compacted upon the metal reenforcing structure": 1 also provide a sand container having one or more discharge 0pen-- ings adapted to register with the opening or openings in the core print and also adapted to receive cbmpressed air above the body ofsand in. it. I also preferably provide means for compacting the sand in the sand container before the compressed air is admitted above the sand. -VVith apparatus of this character provided I assemble the core box with the core-reenforcing structure mounted in it as above described. Then sand of a suitable character is introduced into the sand containeri, I prefer to use fine grained sand moistened with water, such as is commonly referred to as green molding sand. The sand in the container having been compacted in any suitable manner, as by arring or ramming, so as to obviate any voids 1n the contamer, I

effect a substantially sand tight connection a between the core boxand the said container with the interior of the latter in communicationwith the cavity of the core box through the discharge opening or openings of the container andthe opening or openings through the core print, and this is preferably accomplished by pressing the core box and container together so as to tightly clamp the core print betweenthem, thereby at the same time holding the core print in fixed predetermined relation to the corebox cavity. Then the air space above the sand in the container having been suitably connected with a source of compressed air the latter is admitted to the top of the sand and its pressure forces sand through the discharge opening or openings of the container into the core'box so as to fill the same and form a sand'core with a metallic reenforcing structure of the character above described. To insure a complete filling of the core box cavity I prefer to vent any air that may be trapped in the lower part of the cavity, as the sand enters, through suitable 'small vent passages in the wall of the lower part of the core box. The core having been formed in the manner described the connec- I tion between the sand container and the core box 1s separated and the core 1s removed from the core box. the latter being made in sections,

of course, if the core is of a character to require it. I

The core thus produced is adapted to be lowered into the open top cavity of a suitably constructed metal mold body formed to provide a seat for the metal core print and means for accurately locating the core in the cavity of the mold.

With suitable core-forming apparatus such as has been referred to, cores of high quality can be made by my improved method with very great rapidity and at a low cost. I find that the fine green sand can be blown by my method so as to produce cores of highly uniform hardness and, with suitable metallic reenforcing structure, the cores have adequate strength for handling and use in semi-permanent molds andthe use of the reenforcing structure in conjunction with an accurately formed core box produces cores of sufficiently follows I will first describe the apparatus and then point out the manner in which it is utilized in carrying out the method.

In the drawings, Fig. 1 is a front elevation of the assembled apparatus with some of the parts shown in section and with the sand container in position to be filled, the showing of some parts of the apparatus being more or less diagrammatic in character.

Fig. 2 is a front elevation of the apparatus with the sand container moved to register with the core box and-with the source of compressed air.

Fig. 3 is an enlarged vertical section through the core box and some of the adjacent parts of the apparatus as shown in Fig. 2. F Fig. 4 is a vertical section on the

line

4, 4 of Fig. 5 is a section on line5, 5, of Fig. 3.

Fig. 6 is an enlarged front elevation of the core box inverted and resting on a suitable base or support preliminary to the separation of the corebox to free the core.

Fig. 7 is an enlarged front elevation showing the finished core and the three sections of the core box separated therefrom.

Referring in detail to the construction illustrated, 1 designates the supporting frame of the core-forming apparatus which is shown as made of structural steel-forms comprising

front uprights

1, 1 similar rear uprights 1", 1', bottom

transverse members

1, 1 and similar top transverse members 1 1 These structural members are suitably riveted together with strengthening gussets, bars, etc.,

and need not be described in detail as any suitable supporting frame work for the -apparatus can be used.

The core box which is designated in its entirety by 2 is supported upon a bed plate 3 upon which is acljus'tably mounted a pair of

guides

4, 4 adapted to engage the side of the core box and hold it securely in position. The bed or support 3 is mounted upon a cylinder 5 in which is mounted a piston 6 that has a rod 7 that is threaded at its lower end and adj ustably mounted in the aperture of a supportingcasting 8 that is in turn mounted upon the

frame members

1, 1. The piston rod 7 is secured in an adjusted position by a lock nut 9. The piston rod has rigidly secured to it a plurality of

vertical guides

10, 10 in which are slidably mounted depending rods 5*, 5 carried by the cylinder 5.

Screws

11, 11 are adjustably mounted in the lower ends of the guides 10 and serve to adjustably support

buffer springs

12, 12 which thus constitute yieldable stops to limit the downward movement of the cylinder 5. The cylinder space above the piston 6 communicatesthrough a suitable port and a hose 13 with an air valve l4 which communicates through a pipe 15 with a suitable compressed air supply pipe 16. The valve 14 is actuated by a foot lever 17 through a connecting link 18., The lever 17 being fitted with a retracting spring 17.

The core box 2 in the present instance is designed to form the core of a semi-permanent mold for casting skirted aluminum alloy pistons such as are commonly employed in internal combustion engines. The core box comprises a base plate 19 and

side members

20, 21. Referring to Fig. 7 which shows the parts of the core box inverted it will be observed that the base 19 is fitted with a dowel pin 19 adapted to engage a hole 21 in side' is best shown in Figs. 3 and 4 the base and side members of the core box are formed with ribs 19*, 20 and 21 so as to form a corresponding recess in the core which in turn forms a corresponding rib on the under side of the head of the piston casting'that is to be produced. As clearly shown in Figs. 3, 4 and 7 the base plate 19 is formed with a series of minute grooves and

apertures

19,19 which form vent passages adapted to conduct air from the lower part of the core box through the walls of the same to the atmosphere. The

side members

20 and 21 of thecore box carry upright triangular

shaped guide rods

22 and 23 which serve to accurately locate the core reenforcing structure relative to the cavity. of the core box. I

The core reenforcing structure last referred to is designated in its entirety by 24 of said rod being threaded to receive a securing wing nut 24. The lower end of the rod 24 is preferably quartered by splitting it longitudinally and the resulting fingers 24 are spread apart as indicatedin Figs. 3 and 4 to form anchors which eflfeetively support and reenforce the lower part of the core.

Above the core box is arranged a movably mounted sand container and vent-forming unit. The sand container 25 comprises a cylindrical section25 to the lower end of which is secured a slightly tapering section 25 fitted with a bottom plate'25 which has

sand discharge apertures

25, 25. A compressed air cylinder 26 which is rigidly secured to the sand container 25 has a piston 27 mounted in it and the depending rod 28 core to form vents therein. Compressed air can be admitted to the upper end of the cyl;

inder 26 through asuitable port and a hose 30 which communicates with a control valve 31 that in turn is connected by pipe 32 with the compressed air supply pipe 16. To the lower end of the piston rod 28 is connected a cord or chain'33 which passes over sheave 34 mounted on the sand container 25' and a sheave 35 mounted on the supporting frame 1, and has connected'to its lower depending end a weight 36 adapted to retract the piston 27 when the space above it is open to exhaust by manipulation of the valve 31. The weight 36 is also designed to move the sand container and vent cylinder unit bodily laterally as will presently be explained. The sand container and vent unit is fitted with a pair of

supportingrails

37, 37 which run on a plurality of

antifriction wheels

38, 38 mounted on

bars

39, 39 of the main supporting frame structure. Thus mounted, the sand container and vent cylinder unit can be moved to a limited extent horizontally. To affect such movement in one direction a compressed air cylinder 40 is provided in which is mounted.

a suitable piston (not shown) having its rod container 25.

Compressed air can be admitted to the outer end of the cylinder through the supply pipe 32, a control valve 42 and a hose 43. lVhen compressed air is admitted to thecylinder 40 the sand container is moved from the position shown in Fig. 1 to that shown in Fig. 2, and when the air space of the cylinder40 is open to exhaust the weight 36serves 41 suitably connected as shown to the sand 'toretract the sand'container and vent cylinder unit fromthe position shown in Fig. 2 to that shown in Fig. 1.

Above the sand container is a sand hopper 44'wl1ich has its bottom fitted with a discharge conduit 44 adapted to register with the upper end of the sand container 25 when the latter is in the position shown in Fig. 1. ()n the discharge conduit 44 is slidably mounted a heavy collar 45 which rests upon a cut-oil plate 25 carried by the sand container 25. .T he collar 45 rides upon the plate 25 and serves to preventany material leakage of sand when the sand container is moved from it to the other of its working positions.

Ontop of the hopper 44 is mounted a compressed air'cylindei 46 in which is mounted 'a piston (not shown) having a rodv 47 that carries at its lower end a plurality of ram rods 48 designed to be thrust down through the sand in the hopper and. the sand container 25 to compact the sand therein and fill any voids in the sandcontain'er. Compressed is admitted to the cylinder 46 through'the supply pipe 32, control valve 49 and hose 50. The ram rods 48 are forced downwardby admitting compressed air to 51 which is connectedbya cord or chain 52 with the piston rod 47, the chain passing over'suitable guide

sheaves

53, 54.

Above and in vertical alignment with the core box is. supported a chambered compressed air head or cap 55. The lower end of the head 55 is open to communicate with the upper open end of the sand container 25 when it is moved to register therewith as shown in Fig. 2. The upper end of the cham: ber or'head 55 communicates through hose 56 with the compressed air control valve 1.4. In the use of the above described apparatus for the production of cores I proceed as follows: Assuming that the sand container is in the position shown in Fig. 1 and that thecavity. .The core box with the reenforcing.

structure is then slipped into position on the bed 3 and between the

guide brackets

4,4 as

shown in Fig. 1. The operator then moves the air valve 49 to actuate the ram 48 and .thereby insure that the sand whichhas entered the container 25from the hopper 44 is free from voids. Next the operator moves the air controlled valve 42 to admit air to the cylinder 40 and move the'sand container 25 to the position shown in Fig. 2 with said container registering at its upper end with its compressed air cap 55 and its lower end with the core box 2. Next the operator presses the foot lever 17, the first part of this movement serving to admit air to the cylinder 5 thereby liftiiig said cylinder and bed 3 and the eorebox until the'upper end of the cor-6 print 24 engages the lower side of the plate 25 of the sand container 25 and then moves said container itself slightly upward until its upper end similarly engages the same time, a substantially sand tight connection is effected between the core box and the sand container and the core print -is held in fixed predetermined relation to the core box cavity. .The further movement of the foot lever 17 and control valve 14 admits com:

' pressed air to the cap 55 and to thesand in the upper'part of the container 25. The effect of the compressed air upon the sand in the container 25 is to force sand from the lower part of the container through thedischarge openings 25" so as to completely fill the core box and the annular core print 25. with sand, said fillingoperation' with suitable air pressure of about 90 pounds per square inch being exceedingly rapid. Thereupon the operator releases-the I foot lever 17 and as it is retracted by the spring 17 the valve 14 is moved 'to exhaust position, whereupon the weight of the bed 3 and its associated parts and of the sand container andits associated parts cause them to move downward valve 31 to adniit compressed air above the piston 27 thereby forcing the piston downward and causing the vent pins 29 to penetrate the sand of the core and form vent passages therein. As soon asthe valve 31' is returned to-off or exhaust position the weight 36 serves to retract the piston 27 and the pins 29 to the position shown in Fig. 1.

This completes the formation of the core and the operator now draws the core box from its supporting bed 3 and inverts it on a suitable support as shown in Fig. 6., He then separates the core box from .the core by first lifting off the base member 19 and then moving the

side members

20 and 21 laterally away from the core as indicated in Fig. 7.

While I prefer in carrying out my process of making the cores to use a coordinated apparatus of the character of that above described, it will readily be understood that some at least of the steps-of the process can be carried out with the use of simple manual devices. For examplethe core when formed can be ventedby the use of a manual vent pin in the well known manner. Again the' operator can use a hand barto ram the sand down in the sand container 25. And-obviously suitable connection can be made be-' tween the'sand container and the core box and between the sand container and the compressed air head otherWise-than by forcing the parts together with a compressed air cylinder and piston. However,.it is desirable to use a coordinated apparatus because'the filling of the core box with sand by compressed airis effected in-remarkably short space'of time, a fraction of a second sufiicing,

and it isdesirable to have a well coordinated apparatus capable of performing the other operatlons with celerity in order to take proper advantage of the very great speed 7, .with which the core box is filled with sand.

Although in the practice of my process the core box is filled very quickly indeed I find that the action is highly-uniform. .That is to say the core box is always completely filled and the sand body of the core is of uniform hardness. In practicing the process it is highly desirable to form a substantially sand tight connection between the core box cavity and the sand container because'ifany openhand.

ing is left between the core box and the sand I container the escape of sand through the opening may be suflicient to prevent the complete uniform filling of the corebox above referred to.

I consider it highly desirable and essential to provide the lower part of the core box vention, but reference may be had to my U. S.

Patent No. 1,659,837 and to my pending ap plic'ation Serial No. 23,813, filed April 17, 1925, (United States Patent No. 1,684,715) for disclosures of molds in which such cores are used. v

Reenforced green sand cores formed by my improved process have adequate strength for the necessary handling in the making of castings, they are accurate in form ,and dimen-.

sions, and by reason of the metallic core print feature can be accurately located and suspended in the cavity of a permanent mold. The cores made in'aceordance with the pres-' ent process have the added advantage of great uniformity in solidity because the core box can be filled more uniformly by-the action of compressed air than it can be filled by As has been. intimated above, cores can be formed by my improved blowing process with very great rapidity particularly when suitable apparatus is employed. This results in a very'material reduction in the cost of producing such cores aslcompared with the manual method of filling the core box previously devised by me.

While Iprefer to practice my invention in the manner which has been described and indicated in the drawings it is to be understood that there canbe various modifications in the process and the apparatus employed without departing from the invention as defined in theappended claims.

What I claim is 1. The improved process of forming the cores of molds for cup-shape piston castings which cores have a body of green sand and a metallic reenforcing structure comprising a core print portion and an embedded portion rigid with the core print portion, said process comprising positioning the metallic reenforcing structure of the core in the open-topped cavity of a core box with the core print-portion engaging the top artof the core box and sustaining the sai reenforcing structure'in predetermined position in relation Ill .4 to the core box cavity; placing a container of fine green sand in communication with an opening through said core print portion so as to form a substantially sand tight closure of the said opening and the said core box cavity except for the Communication of the said sand container therewith; forcing sand by means of compressed air from said container through said communication into the core box cavity to fill the same; and removing the core thus formed from the core box.

2. The improved process offorming the cores of molds for cup-shape piston castings which cores have a body of green sand and a metallic recnforcing structure comprising, a core print portion and an embedded portion rigid with the core print portion, said processcomprising positioning the metallic reenforcing structure of the core in the open-- topped cavity of a core box with the core print portion engaging the top part'of the core box and sustaining the said reenforcing structure in predetermined position in relation to the core box cavity; placing a container of fine green sand in communication with an opening through said core print portlon so as to form a substantially sand tight closure of the said opening and the said core box cavity except for the communication of the said sand container therewith; forcing sand by means of compressed air from said container through said communication into the corebox cavity to till the same and meanwhile venting air from the lower part of the core box cavity through the core box walls; and removing the core thus formed from the core box.

The improved process of forming the cores of molds for cup-shape piston castings which cores have a body of green sand and a metallic reenforcing structure comprising a core print portion and an embedded portion rigid with the core print portion, said proc' ess comprising positioning the metallic reeniorcing structure of the core in the opentopped cavity of a core box with the core print portion engaging the top part "of the core box and sustaining the said reenforcing structure in predetermined position in relation to the core box cavity; introducing a mass of fine green sand into a container; mechanically compacting the sand in said con- -tainer; placing said container in conimunication with an opening through saidcore print portion so as to form a substantially sand tight closure of the said opening and of the said core box cavity except for the communication of the said sand container therewith; forcing sand by means of compressed air from said container through said communication into said corebox cavity; and reipoving the core thus formed from the core 4. The improved process of forming the cores of molds for cup-shape piston castings which cores have a body of green sand and a metallic reent'orcing structure comprising a core print portion and an embedded portioncore box cavity; placing a container of fine,

green sand in communication with an opening through said core print portion so as to .form a substantially sand tight closure of the said opening and the said core box except for the communication of the sand containertherewith; forcing sand by means of compressed air from said container through said communication into the core box cavity to fill the same; forming in the sand body of the core vent passages opening through the upper end of said body; and removing the core thus formed from the core box.

5. In apparatus for making. reenforcfll sand cores having a body of sand and a metallic reentorcing structure comprising an exposed core print portion, the combination of arcorebox having an open-topped cavity shaped to form the core for a skirted piston casting and formed adjacent the mouth of said cavity to support the core print portion of the core reent'orcing structure with a sand tight joint between said box and core print portion;-a container for sand; means foreft'ecting a substantially sand tight connection between the core print portion of the reenforcing means and the'sand container with the interior of the latter in communication through the corel'prin't portion of the reen forcing structure with the core box cavity;

means for introducing sand into said container; and means for applying compressed air to the sand in the container to force some of said sand into the corebox cavity to fill the same.

6. In apparatus ,for making reenforced sand cores having a body of sand and a metallic reenforcing' structure comprising an exposed core print portion, the combination of a core box having an open-topped cavity shaped to form the core for a skirted piston casting and formed adjacent the mouth of said cavity to support the core print portion of the core rcenforcing structure; a container for sand; means for pressing the core box and the sand container together. whereby substantially sand tight oints are formed between the core box and the said core print portion and between the latter and the sand container with the interior of the sand container in communication through the core 'sand in the container to force some of thethe core box and sand container together to hold the reenforcing structure predetermined position in relation to the core box cavity and to maintain communication between the. interior of the sand container and the cavity of the core box with a substantially sand tight connection; means for introducingsand into said container; and means for applying compressed air to the sand in the container to force some of the said sand into the core box cavity to fill the same.

In testimony whereof, I hereunto aflix my signature.

DANIEL J. RYAN.