US980994A - Method of jolt-ramming molds. - Google Patents

Description

E. H. MUMFORD. METHOD 0F JOLT RAMMING MOLDS.

PPLIOATION FILED 1211.15, 1910.

980,994. y Patented Jan. 10, 1911.

@Wy/1M UNITED sTATEs PATENT oEEIoE.

EDGAR H. MUMFORD, 0F PHILADELPHIA, PENNSYLVANIA.

METHOD OF JOLT-RAMMING MOLDS.

Specification of Iietters Patent.

:Patented Jan. 1o, 1911.

Application led February 15, 1910. Serial No. 544,005.

'of the uneven wear of plunger and cylindercommonly incident to work of this character, resulting from the fact that the molds are generally placed upon the jolt ramming tables without proper regard to the location of the centers of gravity which produces over turning action, or tendency to distortion of the hfting plunger in its cylinder resulting in uneven wear in the plunger that raises the table and guides it in its downward fall. In order that my invention may be better understood I have prepared a drawing, which forms a part of this specification, and whereinj Figure l isa perspective view with a portion of the mold broken away, thefmold being placed in position upon a wedge for' a purpose which will hereinafter be more particularly described, and Figure 2 is a view partly in section, showing the upper end of the plunger and jolt ramming table mounted on th plunger, with a mold set uponthe table in position to be jolt rammed.

In carrying out my invention, I firsttake a mold formed by the use of a pattern board 3, having the pattern 4 located thereon, and the flask 5 in position on the board, the mold part being formed with the sand within the flask either compacted or ready to be compacted properly about the pattern, as indicated in Figure 1, wherethe sand is partly broken out, as is also one portion of the iask in order to showthe pattern. This mold part, I first set upon a strai-ght edge 7 in a position substantially such as is shown in Figure 1, moving it back and forthy until it balances thereon, then forming a mark or notch at l8 upon each of the opposite edges,

vwhere the board rests upon the straight edge,

after which the mold is turned around through an angle and balanced again on the straight edge, obtaining two other marks,`

one of which is shown at 9, said llast mentioned marks -beingon the other two sides of the board,'after which by connecting the marks on the edges and finding where the lines connecting the same will cross, as at` 10, I am enabled to locate the point on the under or im act face of the board-which will bei direct y under the center of gravity of the completed mold.

The mold table is indicated at 11 in Figure 2, and the plunger at 12, the latter working in the cylinder 13, which plunger and cylinder may be of any preferred construction. The upper face of the table is provided with some means for locating or positioning the mold, such for example as the upstanding lug 14, and on the under side of `the board 3 I make a recess just adapted to fit over the lug 14 in the position shown in Figure 2, the center of such recess being located by the crossing of the two lines at the point marked 10.

From .the foregoing it will be evident that in carrying out my invention, I am enabled to get the mold placed on the jolt ramming table with the center of gravity of the mold, or the approximate center of gravity of the mold, directly over the center of the impact surface, on which account there is not any appreciable 1lateral stress or tendency to tilt or unevenly wear the plunger in the jolt ramming operation, whereas if the mold be placed at random upon the table, or if it be placed with the.. center of area of this mold over the vcenter of the table, there will be lateral strains and tiltin tendency due to the fact that the center o gravity is out of line with the center of the lunger or impact surface. -Vhile I have s own the upstanding lug M directly over the center of the table, it is lobvious that it or a number of lugs might be otherwise located, provided only that these are made in such way as to hold the mold in pro er position the essential thing being that t e center of gravity of the mold complete, should come approximately over the center of the im pact surface, or in such `osition with relation to the table and the jar rammin mechanism, as will avoid tiltingv and ot erV unequal strains, however it may be set and secured there.

Most molds and cores are of unevenly distributed weio'ht and are practically 4never set so that tIie weight on the table of the machine does not tend to tip it in one direcp tion or another.

Such tipping causes plun ers to weaning` `theircylinders--at both en s.

In large machines this tipping and wear- Ing moment is very considerable and many machines installed within the last few years are already worn out from this. cause.`

Having thus described my invention and illustrated its use what I claim asnew and desire to secure by Letters-Patent is the followng:-

1. The herein described method of jolt ramming molds which consists in locating a point under the face of the mold directly under the center of gravity of the mold and then securing the mold upon a jolt ramming apparatus with the centerof gravity thereofl directly over the center of application ofthe jolt ramming mechanism.

2. The herein described method of jolt ramming molds which consists in placing the mold upon a jolt ramming apparatus With the center of gravity of the mold, directly over the center of the resistance surface which checks the downward movement of the mold.

3. The herein described method of jolt ramming molds which consists in ascertainlngl by test .the vertical line in which the center of gravity of the mold lies, fixing the location of such line with respect to the pattern late, mounting the pattern plate and mol upon a jolt ramming machine with the said line in substantial alinement withy the axis of the rammer plunger, jolt ramming the mold, and maintainmg the' mold against lateral movement during such rammmg.

In testimon whereof I have hereunto seti` my hand be ore the two subscribed witnesses.

j EDGAR H. MUMFORD.

Witnesses: v

PAUL CARPENTER,

WM. J. REX.

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