US1757226A - Foundry molding box - Google Patents

Description

-May 6, 1930. A. B. SMITH ET-A FOUNDRY MQLDING BOX Fild A ril 6, 1929 2 Sheets-Sheet 1 INVE- mks. A .B.sm;m.

May 6, 1930.

A. B. SMITH ET AL FOUNDRY MOLDING BOX Filed April 6, 1929 2 Sheets-Shee 2 ATTE- Patented May 6, 1930 NIT D srA'r' s fP 'Aranror-rica ALFRED BARTLETT SMITH AND omrronn ROSS-SMITH, OFWOLVERHAMPTON,

, ENGLAND.

roonnnx MOLDING 302;

Application filed April 6, 1929, Serial No. 353,080, and in Great Britain April 16, 1928.

This invention relates to improvementsin molding boxes and the like and refers par-.

ticularly to molding boxes, core boxes, metallic molds for, die-casting and the like of the type in which a number of boxes or molds may be required to be superimposed and accurately located and secured together to form a complete amold. c

a In foundry work, it is a common practice to w m assemble a number of such boxes and locate them relatively to each other by'a number of separate and, in many cases, staggered connections or location devices] This is commonly done by means of pins rigidly attached to one part engaging holes or lugs on an adjacent part or by means of loose pins engaging holes or lugs or adj acent parts. In

some cases the pins and holes are cylindrical;

in others they are V-shaped; butin any case 2 the connection is duplicated between each of the several boxes in one complete mold. It will therefore by obvious, as there must be a small amount of play between eachiattach ment pin and the lugs or holes with which it 7 is engaged, that in a deep casting, molded in a number of boxes, there must be a cumulative error of quite serious proportions. This error must be allowed for in the casting, and on a machined section on a casting may necessi- 3 tate correspondingly greater labour in machining and. losses in metal on the finished work while on an unmachined section on a casting allowance must be made for possible inaccuracies when calculating the thickness or other dimensions.

With location or connection means which function only between adjacent boxes, or a pair of boxes, it is difiicult to maintain anaccurate fit of an attachment pin and the box 4o lugs, forrthe reason that the parallelism of the bores of the lugs cannot be -either'commerlcially, produced or maintained for these purposes in their strict right-angle relationship to the plane ofthe box-part. Accordingly,

- clearances have to be allowed, and. if such clearances as are generally employed are re- 7 duced, then, owing to the entry of dust and fine grains of sand which are trapped between the working surfaces of the pin and hole,ex-

5o 1 cessive binding is caused in assemblyand use underactualfoundryconditions. The forcusual and known methods of location are empl ye a, -p It is an object of our invention to enable common attachment and'locating members to beemployed with a range of several boxes andto render each box quite standard as .to its lugs and attachment means so that-not only is a coaxial location of the variousboxes possible,butfalso a" complete interchangeability of all boxes comprising a range or set .is obtained Another object isto accomp1ish;this in such a manner that, although the tolerance between the common member and the lug of any individual box is smaller bling the boxes in superposed relation and accuracy 1s mamtained over a long period of use. a

in a flange serving the same purpose, and the bores .inthe lugs, or the apertures in the 'flange, are mere clearances formed larger than the pin-member on which the boxes are to Ifit, and thereuponare adjustably secured knife" edged or nose-edged location plates which can be set with accuracy to accommodate the locating :pin member.

areeach V shaped to give a four point contact each oflinedepthonly on the pin member, while at the other side two parallel edged stripsdirected parallel with the axis of the ,box which passes through the lugs, and spaced to give a line contact on two opposite sides of. the pin, will sufiice.

:The combination of these location plates having knife or, nose edged contact lines with an accurately made and gauged, hard, cylindrical pin-common to all the box parts is'a useful, practical embodiment ensuring greater than hitherto,lthere isno difficultyin assem- These location plates at one side of the box 3 or'Figure 4.

accuracy of work and economy in labour and metal. j V

These improved location devices are automatically self-clearing, as sand grains cannot be trapped between the pinand these line contact locationplates; there is no'binding therefore, a much closer fitting pin can be worked easily and smoothly, wear is reduced and great accuracyis permitted and maintained.

We make use of two sets of location plates on each box, one set near the top. and one set near the bottom. This ensures that the box surface and the axes of the pins are held truly at right angles to each other. While it isnot essential to make this provision oneach end of each box part of a pair or set of boxes, when working on flat or hollow" surfaced molds, it is always necessary with one of such parts, and therefore in commercial use we prefer to make it a standard practice. In the accompanying drawings Figure 1 is a perspective view of a box;

Figure 2, is a central longitudinal section thereof on a larger scale.

Figure 3, is a plan of one part of the location plates which. are shown at the-left hand end of Figure 1.

Figure. 4, is a planrof oneof the-plates shown at the right hand end of Figure 1.

Figure 5, is a section on line 5. 5 of Figure In this illustrated example we formfleach box with two lugs a at'each end, 'onenear the top and the other near the bottom, opposing lugs at the two ends being inthe same planes. In each lug is a clearance apertureb large enough to pass freely the pins on which all the boxes are to work. on the faces of the lugs a which are remote from each otheigwe secure at one end two pairs of location plates 0 Figure 3, and at the other'end' two pairs of plates cl Figure 4. The plates 0 are; eachV- shaped in their ends and they are assembled with their V ends oppositeeachother, but

separated sufliciently for the four inclined lines thus produced to fit the cylindrical locating pins, which are to be used with them,

with the smallest working clearance. We find in our own foundry practice this clearance may be reduced to0.0005 v(five.ten-thousandths) of an inch on a pinof 1" diameter. Eachangular edge 'e of these Vshap'ed ends is formed in themanner shown in Figure 5.

" The lugs a at the other end of the box are a similarly provided'with pairs oflocation plates (Z each of which has an edge. f, ,of section corresponding to Figure 5,. along one end. These knife edged ends fare assembled opposite each other, separated s'ufiiciently to fit a cylindrical pin at twolopposite points only under the same conditions of accuracy at these points as in the case of the plates 0. The holes in. the lugs for the reception of the attachment bolts 9 for the location the other end of said the plates 0 and the two edges 7 of the plates 1 d must be set in the same relative position in each box if all the boxes of a set are to be interchangeable and capableof use: on a true cylindrical pin at each end common to all the box parts. For-the setting'of these plates any suitable jig giving this result can beemploy'ed as will be clear to those skilledin the art. A-jig having masterpins, setfor the various siz'esof boxes is a'c onvenient method, the pins being gauged to a size larger thanthe actual pins on whichthe' boxes-are td'work by the extent of the clearance allowed! It is preferred, but is notessentialgto' cast the location plates c anddfand formthe egges e as dead hard edges by the 'use' -of c ills. 7 i

The pins for use with the box partillus trated in the drawings arenot' shown as these are merely true'cyl-indiical pins, preferably hardened steel ofa length to 'accommodate any required number 'of"boxes in superposition; i

We claim I 1; Foundry-molding box or' flask comprising in combination a frame part, lugs? on oppositeends of said frame part, clearance apertures in the lugs, location means adjust ably secured on'said lu gs'to loc'atethe: frame partsat-eaclr end'on a. cyliiidrical location pin passed through said clearance apertures, said location meanslgivm'g POHIlT "COHtQCt'OTL said pin, said location means atone'end'of said frame consisting of opposed plates'having V notches in their opposite edges andat clearance apertures to locatethe frame part at eachend of a cylindrical, location; pin

passed through said clearance: apertures, said location plates at one end of said frame having \l-notches in their opposite edges and at frame having straight opposite edges; V

3."In foundry molding boxesoriflasksof the kind in"which' a, rectangular box'lik'e molding part, is" provided ,at' opposite ends with perforated lugs which cooperate with cylindrical pins'commonto a plurality ofthe boxes to locate the boxes in'proper molding relation one with another, the combination with said lugs of apertures which are clearances on the cylindrical pins with which the lugs are to cooperate in locating said boxes,

plates adjustably secured on the lugs at each end of the box with the ends of the plates opposing each other and overlying the clearance apertures, said overlying opposed ends of said plates being formed with edges giving point contact on the cylindrical plns, and said plates at one end of saidbox part having V notches in their op osing edges the sides of which notches are mife edges; and said plates at the other end of said box part having straight opposed edges longitudinally directed, said straight edges being formed as knife edges.

Intestimony whereof we affix our signatures.

ALFRED BARTLETT SMITH. CLIFFORD ROSS SMITH.

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