US2537889A - Core box vent - Google Patents

Description

M. L. BRICKER Jan. 9, 1951 CORE BOX VENT 2 Sheets-Sheet 1 Filed Aug. 15, 1947 M. L. BRIOKER fwaw ATTORNEYS.

Jan. 9, 1951 M. L. BRICKER 8 CORE BOX VENT Filed Aug. 15, 1947 2 Sheets-Sheet 2 M. L. BRIOKER INVENTOR. '4 p sfib/z ATTORNEYS.

Patented Jan. 9, 1951 CORE BOX VENT Mead L. Bricker, Detroit, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Application August 13, 1947, Serial No. 768,419

6 Claims. 1

This application relates to the metal founding art and more particularly to a durable and economical vent or sand retainer useful in the mass production of cores. For reasons which will become apparent below, these core box vents must be capable of rapid and economical manufacture, they must be durable under extremely destructive abrasive conditions and must. effect a rapid and almost quantitative separation of sand and air.

The repetitious production of foundry cores is conventionally accomplished by molding the core material to the desired shape ina metal core box. These cores are made from a mixture which is basically moist sand to which. has been added a binding agent. To fill the core boxes with this moist sand rapidly and economically and to properly compact the core, it. is the usual practice to transport the sand pneumatically; using an air pressure of the order of ninety pounds per square inch. As the core box is filled with sand, some avenue of escape must be provided for the air" originally present in the core box as Well as the air employed to transport the sand. To be economically feasible this large volume of air must be permitted to escape rapidly and with a minimum of entrained sand.

In continuing attempts to meet these requirements, the foundry art has evolved a large variety of core box vent structures, none of which has proven completely satisfactory from both a cost and performance viewpoint. These efi'orts have resulted in structures ranging from a simple screen to rather complicated venting arrangements. Typical structures for this purpose are described in Unit d States Let rs Patents 2,060.85!) 2,126,091 2,176,328 and 2,238,506.

The chief impediment to the success of these various structures has been the highly abrasive conditions encountered in use. The sand base of the core material is, of course, extremely abrasive and it is unavoidable that some of this abrasive sand is driven through the core box vents each time the core box is filled. This passage of abrasive sand through the core box vents at high velocity has resulted in a rapid cutting action and consequent short life of the vents. Since many core box vents are required in each core box, their maintenance is a considerable item of expense in the core room.

Accordingly it is an obiect of this invention to provide a core box vent which will be economical to produce, durable and highly efficient in use and quickly and easily installed in the core box.

It is a further object of this invention to provide an economical method for the production of core box ve ts materials readily available in the foundry trade.

It is. a further object of this invention to provide a core box vent which will permit the escape of a maximum volume. of air in a minimum period of time and with a minimum loss of sand to the working space in the core room.

It is a further object of this invention to provide a core box vent which will not mar the smooth surface of the cores.

Itis a further object of this invention to provide a resilient core box vent which will vibrate in use and so exhibit self cleaning properties.

With these and other objects in view, the invention comprises the arrangements, con tructions, combinations of the various elements of the structure described in the specification. claimed in the claims and illustrated in the ac company-mg drawings, in which:

Figure l is a plan view of the core box vent as seen from within the core box.

Figure 2 is a sectional view of applicants core box vent taken along the line 2--2 in Figure 1.

Figure 3 is an elevation view of one stage in the manufacture of the spring element employed as the venting medium in applicants st-ucture.

Figure 4 is similar to Figure 1 in that it shows a plan view of a core box vent as seen from within the core box. Figure 4 differs from Figure l in that it depicts a variation in the type of spiral spring member.

Figure 5 is a sectional view of an alternative form of core box vent in which the cotter key is arranged to permit a certain amount of axial movement of the center of the spiral spring element.

Figure 6 is an elevation of one stage in the manufacture of the spiral spring member depicted in Figure 4.

In the int rest of clarity, all of the drawings have been shown four times the actual size.

Basically. applicants invention comprises a resilient spiral spring carried in a tubular shell member adapted to be driven into a corresponding cavityin the core box. In Figures 1 and 2 this shell is designated by the numeral it. This shell it is provided with a shoulder ii and ears 32. This shell M5 is capable of rapid production by stamping from tubing. The actual filtering of the sand from the air is effected by spiral spring it which is wound from a ribbon of spring steel with the long side of the ribbon parallel to the axis of the spring. This wound spiral spring is inserted in the end of shell I0 remote from short lire.

In an SfZOZt to circumvent both of these dil culties, applicant has developed the structure described in this document. Turning to Figure 3, there is depicted the spring steel ribbon and cotter i5. To produce spring is from ribbon M and cotter key i5 it is only necessary to insert the end of r" 2 into the eye of cotter key 55 and apply suilicwnt pressure to fiatten the sides of key eye against the the cotter ribbon. Welding or brazing may be 'esorted to to insure a satisfactory joint between ribbon i l and cot .1 key 55. however, this usually not necessary as sufficient grin can be provided by simple mechanical. pressure. The body of cotter key 15 can now be gripped in the collet of a spring winding machine spring i9 readily produced.

The two halves of the body of cotter key 15 can now be bent into the position shown in Figure 2 and assembled into shell as shown by that figure. When so assembled, the ends of the body of cotter key i5 rest upon shoulder i i and serve to sur ort the central portion of spring 13 against the pneumatic thrust. Alternatively, if such support is not necessar, the assembly or" cotter key and spring can be placed in shell iii with the body of the cotter key unbent, or bent to a degree less than that shown in Figure 2. If desired, any portion of the body of the cotter key may be cut off prior to use to regulate the action of the vent under pressure. In any event, the head of the cotter trey serves to close tile center convolution of the spring against sand leakage and at the same time provides a and efficient arbor winding spring 13.

Figures l and depict another form of applicants invention in whic dillerent iorrn oi spiral spring is employed. In this form of core box vent two ends of the spiral spring element rest he shell and are approximately diametrically opposite each other. This type of construction gives a much stiffer spring action and is somewhat easier to fabricate. As shown in Figure (3, the spring steel ribbon is is see c. in the eye of cotter key i5 at a point approximately intermediate its ends. When so secured the cotter key is rotated to produce the spiral spring element. Under this arrangement, the joint between the cotter key and the spring steel ribbon need not be so secure and in some circumstances can be dispensed with entirely, the spring steel ribbon being merely thrust through the eye of the cotter key.

Figure 5 illustrates that phase of the invention in which the legs of the cotter key are shortened to allow axial movement of the center of spring it.

From the foregoing it can be seen that applicant has provided a novel and efficient core box vent and a method of producing this core box vent from materials readily available and without the need of any special machinery.

What is claimed is:

1. A vent comprising outer shell, a s iral spring element disposed in the outer shell with its plane normal to the axis of the shell and a support comprising a cotter key secured to the inner convolution of the s al spring, the body of said cotter key being spllu to provide a bifurcated sun; t for the central portion of the spring elemer a portion of the shell.

The stru t in claim 1 in which "eci' ed ody abut the interior surends of the intermediate the ends of the face of the s]: shell.

3. The structure recited in claim 1 in which the outer convolution of the spring element is supported by the shell.

4. The structure recited in claim 1 in which the ends of the cotter key remote from the cotter hey eye terminate short of shoulder provided on the outer shell so that a limited axial movement of the inner convolution of the spiral spring element is provided.

5. A core box vent comprising a cotter key and a spiral resilient element, the body of said cotter key being sp it so that the tWo ends thereof are separated a substantial distance and the inner convolution of said spiral resilient element being secured in the eye of the cotter key.

A core box vent comprising a cotter key and a spiral resilient element, the body of said cotter key being split so that the two ends thereof are separated a substantial distance and the inner convolution of said spiral resilient element being secured in the eye of the cotter key at a locale intermediate the ends of the spiral element.

WIEAD L. BRICKER.

The following references are of record in the file or" this patent:

UNITED STATES PATENTS Number Name Date 357,956 Fraley Feb. 15, 1887 443,256 Logan Dec. 23, 1899 1,150,919 VJarmington Aug. 24, 1915 1,224,598 Burch May 1, 1917 2,033,148 Coulornbe W June 8,1937 2,127,219 I-lirshfeld Aug. 16, 1938 2,203,315 Vivie June i, 1940 2,238,506 Rienacker Apr. 15, 1941 2,263,974 Eienacker Nov. 25,1941

FOREIGN PATENTS Number Country Date 415,093 Frane July 4, 1910

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