US1007458A - Means for eliminating risers on castings. - Google Patents

Description

R. P. LAMONT.

MEANS FOR ELIMINATING RISERS 0N CASTINGS.

APPLICATION FILED MAR. 24, 1911.

1,007,458, Patented Oct. 31, 1911.

nornar 1'. LAMONT, or onroneo, rumors.

MEANS FOR ELIMINATING RISERS 0N OABTINGS.

Specification of Letters Patent.

Patented Oct. 31, 1911.

Application filed March 24, 1911. Serial No. 616,772. i

To all whom it may comm: I

Be it known that I, ROBERT P. LAMONT, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Means for Eliminating Risers on Castings, of which the following is a specification.

My invention relates to the art of casting molten metal in molds and has particular reference to an apparatus for roducing castings of steel or other metals without the usual risers on the solidified metal.

It is, of course, necessary in order to prevent the occlusion of gases within the molten metal and the consequent weakening of the casting that free exit for the gases should be provided. This object has not hitherto been completely obtained in practice be cause in order to prevent the waste of metal and also the increased cost of removing the sprue or riser from the casting it has been customary to restrict both the number and area of the escape a ertures as much as possible consistent wit a fairly free vent for the occluded gases. Y

My invention proceeds upon the theory of providing adequate and ample escape for the gases and this I do by making the vent of practically uniform cross section from end to end and then embedding in the wall of the mold at the inner end of the escape opening a perforated body of silicious material, the area of the perforations being adequate to permit the free escape of the gases while the material constituting the perforated body coming in contact with the hot metal will chill the latter and prevent its rise within the cavity.

Therefore one of the objects of my inventionis the provision of means whereby castings may be made in properly vented molds without the formation of risers.

In carrying out my method I prepare the mold which is to receive the casting, pro-- viding a liberal number of vent holes therein. These vent holes are then covered at their inside ends with a perforated body of silicious material. These openings permit the escape of the gases but when the molten metal reaches the vent' it contacts the area of cold material and is chilled or freezes without any portion thereof rising into the vent hole. After the casting is sufficiently hardened or set it is removed from the sand audit will he found that the perforated body being preferably composed of core compound has practically disintegrated and the casting is left substantially smooth and without the usual. riser which 'would have to be removed by sawing or other means. As .will be seen, by my novel means, the molds are well vented and the loss in metal and the cost of removing the risers is eliminated. I

I have shown in the accompanying drawings the application of my novel method and apparatus to a mold for forming cast steel sideframes, but it will be understood that it may be applied to the production of cast-ings in general.

While my invention is adapted for use in the manufactureof small castings, it is also particularly advanta eous when applied to the manufacture of Iarge castings; that is, castings weighing in some instances many tons, and which may be of such design that if vented and a riser formed at the proper location in the mold for the most advantageous results it will be impossible or very difficult to remove the riser after the casting is formed. As will be understood, these risers on large castings contain a large amount of metal and must necessarily be sawed from the casting and unless the casting can be placed in the sawthe removal of the riser is difficult. Therefore my invention can be applied to the manufacture of such castings in a most advantageous manner; that is, the mold may be vented at its proper points to secure the best results and the risers formed where they can be easily removed.

My invention will be more readily understood by reference to the accompanying drawings, wherein-.-

Figure 1 is a view of the drag of a mold showlng a sideframe casting therein; Fig. 2 is a section through the mold taken on a line through the different vents and pouring gate; Fig. 3 is an enlarged fragmentary detail showing the application of a perforated silicious body to the inner end of the vent, and Fig. 4 is a view of a perforated body such as is contemplated in this invention.

Referring more particularly to the drawings it will be seen that I have shown my invention applied to a mold wherein a cast steel side frame is to be formed. This mold is composed of a lower or drag portion 10, suitable side walls 11, and a cope 12. Within this cope I provide a pouring gate 13,

' and a plurality of vents 14. While I have shown four vents at difierent locations, itwill be understood that this number may be increased or diminished as desired.- These,

vents or riser openin are of uniform cross section and at their Inner ends at the point defining the outline of the casting, I mount a body 15, preferably of the form shown in Fig. 4; that is, composed of a circular body of silicious material of suitable thickness having a plurality of perforations 16 therein.

As will be understood, the mold is first prepared in the usual manner with the pourmg gate and thedesired number of vent lators in the cope. The cope is then placed on the drag and the metal poured through the pouring gate. As the molten metal flows through the passages forming the outline of the casting to be made, the gases and confined air may escape through theapertures 16 in the body 15. However, as-the metal rises to the lower end of the vent openings,

' it will contact the area of cold material and freeze, its rise through the openings being thereby prevented. 'After the casting has set it is shaken from the mold and it will be found that there is no metal to be removed except the metal which is left in the sprue or pouring gate. V

In practice I have found that the plate which is best adapted for use as above described is the one wherein the area of the material is at least equal to the area of the metal will be very small and will be inthe form of thin projections, they may beeasily removed without the use of machinery It will beunderstood that my invention applicablerto all forms of castings and that the means shown for restricting the vent opening tov the extent of preventing the rise of metalat the same time permitting the escape of gases, may be carried out with other means than that specifically herein described and shown.

It will be understood that although I have described my invention as though the formation of no risers whatever was contemplated, it may be found expedient in the manufacture of certain castlngs to form risers where they may be easily removed, in

my invention.

I 'clalmz 1. The combination of body of molding material having a mold cavity and avent,

and a perforated body of silicious material i associated with said vent permittingthe escape of'gases therethrough but preventing the molten metal from entering the vent, substantially as described.

' order to provide a head of metal for shrinkage purposes. The mold may be vented at- :other points as needed, in accordance with 2. The combination offa body ofmolding material having a mold cavity and a ent, and an apertured silicious body located at the innerjend'of said vent, said silicious body .permitting'theescape of gases through: the aperturesbut preventing the molten metal from entering the vent, substanially as described.

a nlurality'of vents therein, and, a -perfo-,

rated body of silicious material seated at the inner end of eachfof said vents'and adapted to permit theescape of gases but prevent the rise of metal into said vent, substans tiallyas described. 1

1., Amold' for making castings comprising' inrombination'adrag, acope havin .a pluralitybf vents therein, and a plum it "of perforatedsiliciousbodies whose area 0 "material'gis-jat"least equal to the combined area} fofli the}perforations I therethrough as-' sociatedwithsaid vent and.- adapted to permit thejes'cape "of gases therethrou'gh and prevent the, entrance "of the molten metal into the vent,'-substantially as described;

' flit, RoBERT P; LAMONT.

witnesses'z 1 SM. Dam-me,- O Ti Jones. I

' 3. A 'mold for making castings which comprises in combination a drag, a cope having

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