US2677160A - Core box dowel pin - Google Patents

Description

May 4, 1954 E. F. PETERSON CORE Box DowEL PIN 2 Sheets-Sheet l Filed Nov. 16, 1949 INVENToR. www@ f Pezewo/L i/w( K4/agay@ May 4 1954 E. F. PETERSON 2,l,677,l60

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Patented May 4, 1954 UNITED LS. 1Q-.FFI

CORE BOX DOWEL PIN Edwin ;F. vPeterson, rKiewanee.- L'Ill.

App'IicationNovember" 16, 1949, SerialNo. 127,648

'L2 lams. 'l rIhis invention relates Vto dowel pins ion-use in' foundry work for'registry 4of composite mold sectionsand 'more' specica-l-ly `to dowelr pins used for the lscope and-dragsections lof Vcoreeboxes.

n'Some of 'the principal' objections -to the ldowel pinsnow lin use-are that' the pins `work loose, and that they tend to deface and damage the core` box. After core removal, the box iscl'osed for furtherl sand insertion, "but -a "careless uoperator hmay drop' or 4throwV the'cope on the drag causing thepins to pe'en' or chip one or "the other ofthe core *box parts depending on which part carries the pins. Repeated separation and combining'of the core box parts will eventually lead "to wear at the pin receiving epeningseven when `such work is carried'out by skilled and careful'operators.

Loosening of the dowel pins ususal'ly is brought on by tapping themold'parts in freeing 'the core.

Larger or more AIintricate cores may require greater'iorce lso thatv by rapping 'eithersection of *the core box, the cope or the drag, this force is .directly transmitted tin'oughthepins. The dowel pinsfmay work loose in the threads, actual play may develop, and these pins may also -be come bent. A Bending of the" protruding pins may happen through accident `lor carelessness when the'mold orcore parts are left open and'p'a-rticularly with the use' ofsolid metal'pins Y*Theniain purpose ofthe dowelp-inof the presl ent vinvention is to' provide'a vpinthat will save the mold or core box parts to considerably prolong vthe 'life `'of such parts and 'to cut down maintenance costs as well as reducing the costly repair time of such molds or core boxes.

'The pin is constructed with a resilientendto prevent damage and Wear toV the pin receiving core part. And it is aY further object of the'invention 'to carry 'the pin in 4a resilient mounting whereby the pin will not become bent by accident or through lateral engagementby the .core part that is `being brought into registry with thejpin during normal foundry practice. "Dropping of the dowel pin core part will not* bend thepins even in 'the event that the'part'strikes" theloor on 'a pin, *by'reason' of 'the resilient'or`iiexible mounting herein dis'closed'and described.

Aistill further Vobject of the-invention is to provide a v'dowel- Apin-having the :ability ,to'rernain tightin the'mold or core 'part to which it connects thus eliminating objectionable' loosening of r`thepins. r The-pins vremain -as securdgand need no tightening or checkingto-seeiif `vtheyare stilly @in the position' necessary* yto carryout the foundry work for Winch they 'were `intended.

"f-By producing #a pin with a `threaded rubber base a `friction element 'is :devised which, VYwhen threaded into position ina'core box part, resists loosening ofl the rpin 'structurel under normal conditions of ruse. -Any rapping shocks aga-inst the boxfwill beabsorbedin the -bodyof therubber mounting to 'make' 'fthe latter vibration -f ree. And twofold, the pin will be separated from metal contact with the' lbox to cushion 4mount the `pin in operative-positionwithrespect to the Abox, and in a resilient lba-se -eounteracting bending -of the pin V'as well as introducing 4some endwiselresiliency to the pin.

l The 'endwise resiliency of the pin will b elmted but eiective and one of the-mainobjects of this invention is to obtain a pin and rubber baserunit with good union to prevent separation of the parts. The-use-of a hollow pin provides a good bond with va rubberbase that not only engages the outside of `the}:vin lbut extends 'upwardly through the pin. "Fo carry lthis idea further,` a solid -pin `can be used with a 'threaded exterior or other y*contour -for obtaining a good -bond with the base rubber molded thereon. 'Or a sleeve pin with radial openings may -be employed to obtain -a goed *bonded unionand to place-some of theV rubber iinshear -as v-welllas in bonded surface Jcontact.

The dowel pins may be threaded into place in a core'box by proper 'clampingtools 'to gripthe metal pin. Another 'method to provide "each pin -Wi"th.a-' special socket in the metal portion foi-'la wrench-tent the socket, the latter :being axially `located on the `to increase the .ea-se of vattaching orremoving a pin.

Gne other obj-ectof 'the present invention is toconstructthe 4dQWel'pin.units in a A'relative size ratio wherein lthe 'bodyfis smailer than the body -of :thc-)ibaseand vd enit'ely small enough to :be :able to ,pass freely 4.through `the :core box opening for the.. dow'el This /feature fis exceedingly important. with :pins Vf-.utilized in iconnection f' with large longdraw :boxes zthat vghave their .respective parts manipulation fby 1 Power machines.

.Any misalgnment of the `composite .core box parts is `disastrous to boxes ot this type causing bending of the .pins and .damage or destruction to a `Costly core makingapparatus. With .the pin of 'the ,present invention, .suchaccidents .through carelessness or other `c onditio'ns'are avoided since the pin, if struck 'by a closing machine actuated part, will shear throu'ghgthe rubber mountingand throughthefdowel pin hole .Without' bending and causing damageto the core box parts.

v5@ther `Aobjects and advantages relating Vto dowel pins of this character and invention shall hereinafter appear in the following detailed description having reference to the accompanying drawings forming a part of this specication.

In the drawings:

Fig. 1 is a vertical cross sectional view taken through a conventional core box with the cope and drag registered and in place as determined by the dowel pins of the present invention to illustrate one typical installation of pins of this design;

Fig. 2 is a side elevational view of a dowel pin as the same appears per se, and removed from the core box;

Fig. 3 is an axial cross sectional view of the dowel pin as taken substantially along the line 3-3 in Fig. 2;

Fig. 4 is an end elevational view of the dowel pin as seen from the top in Fig. 2;

Fig. 5 is a transverse cross sectional view through the dowel pin structure taken substantially in the plane of the line 5-5 in Fig. 3;

Fig. 6 is an axial cross sectional view of a modified construction of dowel pin embodying certain other features of advantageous function;

e Fig. 7 is a side elevational view of a solid metal pin in a rubber mounting base for use with core making boxes of the long draw type that are adapted to machine operation under power opening and closing of the core boxes;

Fig. 8 is an axial sectional view of a dowel pin of a modified construction; y

` Fig. 9 is a bottom end View of the pin shown in Fig. 8;

Figs. '10 and 11 are axial sectional views of dowel pins embodying certainother features all contributing to the feasible use and long life operation of dowel pins of this invention;

Fig. 12 is a transverse cross sectional view of thepin in Fig. 1l and as seen substantially along the plane of line I2-I2 therein; and

Fig. 13 is a fragmentary view of a core box part in section to illustrate the manner in which a socketed dowel pinmay be threaded home in a receiving threaded box opening provided for such a pin. l

in Fig. 1, a typical mold or corebox I is shown having a cope 2, a drag v3 and a Vplurality of suitably positioned dowel pins such as 4 providing the registering agencies for the cope and drag, and formingV the principal devices of this invention. Each of the dowel pins 4 has an externally threaded base 5 with a contiguous flared head 6, and a pin l projecting upwardly concentrically with respect to the base and ared head.

Although the dowel pins 4 may be interchangeably used between cope and drag, Fig. 1 shows the dowel pins as secured to the drag 3 with the pins in holes 8 inthe cope 2. A receptive sleeve socket 9 for a dowel pin 4 may be used in alignment with the opening `3. Such a sleeve socket 9 may be provided by first drilling a suitable bore, then flaring the bore as at I0 for the head II of the sleeve socket 9 and then by reaming followed by tapping the drilled bore with suitable standard thread tape to form the threaded interior IIa for the threaded portion of the sleeve socket 9.

The drag is prepared for receiving the dowel pins 4 in fixed relation thereto by providing widening outwardly at the parting line of the core box drag 3 or similar mold part, as best shown to the right in Fig. 1.

Head 6 of base 5 terminates in a transversely positioned shoulder I3 forming a ledge encircling pin 'l and in plane normal to the axis o the pin. The ared counterbore 12a of the threaded hole I2 is proportioned for size and depth to snugly receive the ared head 6 and preferably should be made to bring the shoulderli of the head 6 flush with the parting surface plane I4 of the drag 3 or slightly below this plane. Thus the pin projects upwardly from the surface I4 Yof the drag 3 and each pin terminates with a rounded cap I5.

The pin 'I is a composite unit comprising metal sleeve I6 which is completely illed with a resilient composition or material such as rubber Il which forms an integral part of the cap I5, the head 6, and the threaded base 5 which are all made out of the same material and are all contiguously formed in a bonded mass. Nesting of the resilient threaded base .5 and its flared resilient head 6 within the threaded opening I2 and conical flare l 2a tends to cause compression of the resilient material I1 against the metal sleeve or pin i6. Sleeve I6 is exposed above the shoulder I3 of head 6, but the lower end I8 of such sleeve is xedly bonded into the head E and base 5 as best shown in Fig. 3. The open ends of the sleeve IG are each ared radially outwardly at I9 and 20 to eliminate right angle metal corners which have a tendency to produce fault lines to weaken the adjacent rubber lead-v ing to cracking and final rupture of the adjacent rubber portions at the right angle locations.

The pin 'I is sturdily supported but it has the ability to actually tilt in its rubber mounting comprising the head 6 and base 5 and as indicated in broken lines at la in Fig. 3. This is I. only possible when the cope 2 is not seated upon the drag 3. When seated the pin 'l is held against tilting in hole 8 in the cope 2, and all relative sliding of the cope 2 with respect to the drag 3 along the parting plane I4 is directly and positively counteracted by the pin I and heavy rubber iare of the head 6 at the plane ofthe shoulder I3. In other words, the only possible force on the pins with the cope and drag in place is a transverse shearing force which is never great enough under normal operating conditions to do any harm to the pins 1.

The resilient cap end I5 of the pin presents a cushion on the pin to eliminate all peening of the removable core box part as well as scratching or defacing the same as such part '1s placed in position upon the pins, etc. This saves the mold or core box parts as well as safeguarding the operator from injury such as can be caused by manual contact with a pin particularly with one that has become burred or defaced. Since the pin 1 is composed of a sleeve I6 and a bonded rubber core I1 with the normal outcrop I5 shown, such a pin will have the further advantage of always presenting a rubber end if the metal sleeve i6 wears at the top edges under continued use. Rubber presents a greater tenacity to wear than metal particularly under conditions where sand is used, so that the rubber wear will be significantly retarded with respect to the wear of the metal parts of the pin. Thus the cushioning function of the dowel pin end will be maintained for the life of the pin.

' The threaded base 5 will frictionally resist` loosening of the dowel pinV once the latter has been screwed tightly linto the. threaded hole I2, and

this action supplemented by :a compressive wedge action fof the flared head-iii inthe flared Yopening l2a will I'hold thed'dewel pin unit xed operative relation in a moldor core vb'oxpar-t under all conditions oiopera'tion Tapping, rapping or -excessive jarring will not loosen a pin of this construction which isresiliently mounted land insulated by robberifrom ,the .metal bodyof the core box.

And as stated before, the pin can fulcrum within the .mounting to tilt, thereby providing a resilient pin support in a xed .socket to counteract bending of the pin even under extreme conditions -of unsatisfactory voperative use. The base and all of the contiguous .integral rubber parts thereof will at all times return the pin to its normal upright position. The pins are also Icapable of slightcompensation for'inaccuracies as in cases'where three or founpins are in Vperfect alignment Land one is a few thousandths of an inch off. Automatic adjustment is also possible with resilient pins of this kind where the mold or :core box parts may undergo some warpage or shrinkage and expansion.

Another important factor is the ability of the pins to shear through their mountings if something should cause misalignment under pressure closing of the core box parts, or if some foreign object should come between the parts.

The dowel pin 2l shown in Fig. 6 is made with a longer threaded base 22 that may be screwed into an appropriately threaded opening in a core box part. The greater thread length circumferentially introduces greater friction to hold the dowel pin iixedly in place after turning and threading the unit into a socket by means of a pair of pliers or other suitable tool. Base 22 also has a shoulder 23 surrounding the sleeve 24 comprising the pin 25 that is headed with a cushion top 26.

This construction embodies further means for frictionally holding the cope in place upon the drag by providing an annular recess 27 around the sleeve 24 and by filling in the recess with an external rubber sleeve 28 as an integral and contiguous part of the rubber structure ofthe dowel pin t. rThe external diameter of the rubber sleeve 28 is preferably made slightly larger than the pin sleeve diameter so that the cope pin bore will tightly and frictionally receive the rubber sleeve 28 when the cope is fully nested upon the drag. Sleeve 23 may be formed at any point along the exposed portion of the pin 25 depending upon the conditions of operation and the action desired. A further embodiment of this kind is shown in Fig. l0.

Fig. 7 shows a pin that is much like the dowel pin shown and described in Figs. 1 to 5. This pin 29 is a solid metal pin having an enlarged shank bonded into a resilient rubber mounting base 3i threaded at 32 and having a iiared head S3. This type of pin is used for heavy deep draw work where a power operated machine brings the cope and drag together. A rubber tip could be used on pin 29, but since machine alignment is here employed, the tip can actually be omitted. If something should happed tothrow the pin 29 and its receptive opening in cope out of alignment, the pin would be driven through base 3l as indicated by the dot and dash lines 3d and out of the threaded opening 35 in the drag lug 36.

In the forms previously described, the dowel pins are threaded into position by a suitable wrench adapted for clamping the metal pin. Fig.y

CII

8 contemplates :us'inga solidmetal pin 13.1 having a hexagonal socket38 'in the :exposed bottom-end' thereof. "Thisfpin lhasa-groovedfor threaded end 39 to obtainadditional 1bonding surface to vx the pin 337 into -the-threadedfrubber base 4i) vand thus to permit*threading-the entire unit into the threaded--openingJM in core part d2 by 4theuse of a hexagonal 'socket wrench. Basel is shown vas vhaving an annular flange #43 `in place of-a flared -head-tofeontemplate using heads of a different 'shapeand las -in thiscase one that has amore abrupt'seating surface to come `to a fairly definite stop Ion-the shoulder v44 of a'core box 1recess 45,

Fig. -10 demonstrates the use of a covered pin 126 having a base 941 with -a rubber cover '48 :of norma-l pindiameter-projecting contiguousl-y from the base fill and over the stein and Vendofthe pin d'5. Pin '4G is made with a rough con-tour at t9 'for better'bond 'with the rubber base lall, and vthelower end 'ef pin i5 is exposed-to present a wrench socket 53 at its axial center for threading the dowel pin unit into place in a core box. The introduction of the socket in pins of this kind makes it possible to rubber coat the pin for a complete protection along its height and at its end.

One further arrangement of a dowel pin structure is showed in Figs. 11 and 12 wherein radial openings or depressions are employed to enhance bonding the hard pin with its resilient mounting and to place some of the rubber in shear to withstand any relative turning loose or parting of the main pin elements. This dowel pin uses a hollow or sleeve pin 5l that may be of an external contour terminating in a common cylindrical plane of pin diameter or round as shown, having a hexagonal interior 52 to receive a wrench therein for securement of the pin with a core part. Pin sleeve 5! is perforated at 53 and a molded rubber base 513 is secured to the sleeve passing through the openings 53 and lling the hexagonal interior to terminate in a cap 55 at its free upper end. In this structure the hexagonal interior of the pin 'counteracts rotation of the sleeve pin under force while the base 54 is bonded thereto and to the outer surface of the pin, and portions 56 of the base are rubber slugs offering shearing resistance to further restrain relative rotation between the 4connected down pin parts.

Fig. i3 illustrates how a wrench 5l with an angle handle 58 can be used in a wrench socket 59 of a dowel pin te to screw the base 6I into place in a threaded hole thereby seating the head 62 in a core part S3 for operative use. Pins such as shown in Figs. 8 to 12 may be fastened in this manner to position the same in a core box part for operative use in foundry core making or molding practice.

Changes and modincations in the exact structures shown and described are contemplated in carrying out the principles taught by the fundamental inventive concept herein presented. All deviations in the exact form and combination of elements of the dowel pins shall, however, be governed by the breadth and scope of the language of the appended claims defining the invention.

What claim is:

l. A dowel pin for registering core box parts comprising a metal sleeve having its terminal ends internally flared radially outwardly at their peripheral portions to provide a symmetrical unit, and a molded rubber body bonded to said sleeve and having one portion thereof filling the sleeve and protruding from one end thereof to form a resilient cap of sleeve diameter on said one end and blending into the exterior contour of the sleeve adjacent the flared portion of the interior of said one end, said body having another portion thereof protruding from the other end of said sleeve and partially covering the exterior of said sleeve to provide means to secure the sleeve into an opening in one of the core box parts.

2. In a dowel pin for registering coacting core box parts wherein one part has an outwardly flared opening therein terminating internally with a threaded bore and the other part has a pin receiving opening therein, the combination of a hard bodied pin for said core box part opening, and a base connected with said pin to secure the latter to said one core box part, said base being constructed of resi1ient material and comprising a threaded end portion having a llared head thereon, said threaded portion of said base being adapted to frictionally retain the base 8 within the internally threaded bore of said one core box part, and said flared head of the base comprising means to snugly nest Within the outwardly ared opening in said one core box part and adjacent the threaded bore therein.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 279,557 Flint June 19, 1883 1,743,492 Sipe Jan. 14, 1930 2,217,367 Horsch Oct. 8, 1940 2,221,141 Kindt NOV. 12, 1940 2,273,102 Harris et al Feb. 17, 1942 2,423,341 Peterson July 1, 1947 2,499,146 Kindt Feb. 28, 1950 FOREIGN PATENTS Number Country Date 257,703 Great Britain Sept. 9, 1926

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