US1803300A - Permanent mold - Google Patents

Description

April 28, 1931. E; e. FAHLMAN 1,803,300

PERMANENT MOLD Fild July 12, 1929 4 SheetS-Sheec 1 M 2 BY Fig.1. 4

ATTORNEYS April 28, 1931.- E. G. FAHLMAN PERMANENT MOLD Filed July 12-. 1929 4 Sheets-:Sheet 2 $355M 9. E. BY I ATTORNEYS April 28, 1931; 'r FAHLMAN 1,803,300

I PERMANE T MOLD Filedfiu 12, 1929 4 Sheets-Sheet 3 ATTORN EYS F1 v INVENTOR' Qua/41f E. G. FAHLMAN' 1,803,300

PERMANENT MOLD April 28, 1931.

Filed July 12, 1929 4 Sheets-Sheet 4 NVENTOR BY 0 ATTORZM v Patented Aim as,- 19 1 UNITED STATES EVERETT G. AHLMAm'oF cLEvEtANn, omo; ASSIGNOR. TO THE I'ERMOLD comamr,

OF GLEEVEIAND, OHIO, ACOBPORATION OF OHIO This invention relates to permanent metal 7 molds for casting metal articles and more particularly to-molds for casting meta-lshaving a relatively high crystallization shrinkage and a relatively loyv fusing point such as aluminum and its alloys.

Thepresent invention has for an important object to provide a mold for casting hollow articles which will produce articles wh ch have more nearly perfect uniformity with respect to external and internal dimensions and having external surfaces WhlCll are smooth throughout the extent thereof.

A further object is to provide 'a mold in whichthe entire casting cavity or substantially the entire casting-cavity is formed 1n oneof the metal mold membersso that the exterior surface of the casting is formed against asmooth continuous surface.

A further object is to provide a mold member in which the entire casting cavity or substaaitially the entire casting cavity is formed which has agate for admission of molten metal to the casting. cavity which is so designed as to permit the mold member to be ,moved axially with respect to a casting formed therein to free the mold member from the casting and sprue. I I

A further object is to provide a mold of the character above referred to which is provided with a core member mounted formovement into and out of the mold cavity of the one piece mold member and provided with actuating means whereby it may be movedoutwardly to'free a casting from the core.

- With the above and other objects in View, the invention may be said to comprise the,

mold as illustrated inthe accompanying drawings hereinafter described and particularly set forth in the appended claims, together with such variations and modifications thereof as will be apparent to one pertains.

skilledin the art to Reference should be had to. the accompany ing drawings forming apart of this specification in which: 7 A

- Figure 1 is a side elevation of a mold embodying the invention showing the main mold member in elevated position.

Application filed July 12, 1929. Serial N'o. 377,633.

I entire exterior surface of the casting which the invention ap Fig. 2 is a central vertical section throng I21 the mold taken on the line indicated at 2. in Fig. 1.

Fig. 3 is a central verticalsection through the mold with mold members in operative position and with a casting in the mold.

Fig. 4 is a section taken cated at H in Fig. 2.

Fig. 5 is a central vertical section through a mold. of slightly modified construction showing a casting in the mold. Fig. 6 is a sectional view of the mold shown in Fig. 5 with the mold members separated. The permanent mold of the present invent1on is a horizontally divided mold in which the upper section is the main mold member and has the casting cavity formed therein and in which the lower section forms the base of the mold and carries the core uponwhich the interior of. the casting is formed. The gate for admitting molten metal is formed in the upper mold section and opens into the on the line: indiupper end of the casting cavity. The upper drawing is designed for casting an end member of a gear'housing, the upper section of the mold having a cavity conforming to the and the bottom sectlon or base member carrying core surface .of the casting.

members 'each' conforming to the interior As shown in Figs. l'to 4 of'the drawing, a

mold is mounted upon a supporting frame' l which is provided with a horizontal bed 2 eat upon which is'mounted a mold base 3, spaced above the bed 2 and supported on standards 4' extending upwardly from the bed. The mold base 3 has fixed thereto a main core member 5 and centrally of the main core member 5, there ,is slidably mounted an upwardly projecting core pin 6. Laterallyof the main I core a core pin 6, there is mounted a stationa pin 7 secured to the main core mem r 5.

The slidable core pin 6 is guided for vertical movement through the main core member and is carried by the upper end of a vertical rack 8 which extends downwardly through and is guided in the bed 2. The rack 8 is engaged by a pinion 9 fixed to a transverse shaft 10 and this shaft is provided outside the frame with a hindle 11"by means of which it ma be turned to adjust the core pin 6 upward y or downwardly there being a shoulder 6a at the base of the pin 6 which engages with the bottom of the base member 3, to limit the upward movement of the pin. For freeing the casting from the core member 5, a series of Vertical thrust pins 12 may be providedaround the bottom of the main core member 5, these pins being mounted upon a head 13 attached to the upper end of a vertically disposed rack 14 which is engaged by a pinion 15 'on a transverse shaft 16, which has a handle 17 at one side of the frame by means of which the head 13 may be moved vertically to move the thrust pins 12 from a position flush with the top of the mold base upwardly to lift the casting and free it from the core member.

The upper main mold member 18 is secured upon the upper ends of vertically disposed rack bars 19 which are slidably mounted in the bed 2 adjacent opposite ends thereof and, beneath the bed 2, the rack bars 19. are engaged by pinions 20 fixed to a transverse shaft 21 which projects beyond one end of the frame and has attached thereto handle bars 22 by means of which the shaft may be turned to raise and lower the rack bars 19 simultaneously to move the main mold member 18 upwardly away from the base member or downwardly into engagement with the base member. 7

' The mold member 18 has a bottom face 23 I I which engages with themold base 3 and is cap 25 which is rigidly secured to the body ort-ion of the mold member by means of olts 26, the ca and the body of the mold having accurate y machined contacting faces so that the surface of the cavity is smooth and continuous. p

Theupper end of the casting. cavity extends into the cap 25 and the cap is provided with a (gate 27 opening centrally into the upper en of the; cavity. The gate 27 has a gradual taper upwardly from the lower end 1 thereof which opens into the casting cavity so that an upwardly tapering sprue is formed therein from which the gate portion of the mold may be separated by upward movement of the mold member. If desired, the gate 27 may be formed in a metal insert 28 which fits in a bore formed in the cap 25 and which has an external groove 29 which forms an air chamber which serves to retard the conduction of heat from the sprue and prevent freezing in the gate which would interfere with free flow of metal to all parts of the mold cavity.

- In the operation of the mold, the main mold member 18 is lowered onto the mold base 3, the slidable core pin 6 is moved to its uppermost position and the head 13 is moved downwardly to withdraw thrust pins12 from the casting cavity and to position them with their upper ends flush with the surface of the base member. With the core members assembled as above described, the lower end of the casting cavity is closed by the base member 3, the main core member 5 and core pins 6 and 7 conforming to the interior of the casting and to the apertures thereof, while the cavity 24 of the main mold member 18 conforms to the entire exterior surface of the casting to be formed.

Mold metal is poured into the cavity through the gate 27. which is of relatively large diameter and insulated by the annular air chamber 29 so that the metal may flow to all parts of the mold cavity before the sprue portion begins to congeal. As soon as the casting has solidified, the core pins 6 and 7 are retracted by actuating the rack 8 and the main mold member is lifted off the casting by actuating-the racks 19, whereupon the casting may be readily forced off of the main core member 5 by actuating the rack 15 carrying head 13 and thrust pins 12.

In Figs. 5 and 6 of the drawings, there is illustrated a mold for casting an article of somewhat different form than the casting formed by the mold illustrated in Figs. 1 to 4. In this modification, the mold is supported upon the frame 30 having a horizontally disposed bed 31 which is provided with a central aperture in which is mounted a bushing 32 which projects slightly above the surface of-the bed and which has an outwardly projecting flange 33 at its lowerend which is secured to the bottom of the bed by means of bolts 34.

The bushing 32 forms a guide for a vertically movable core member 35 which has a slidin lit in the bushing and which may be provi ed with a centrally disposed pin 36 which projects from the'upper end thereof.

The core member 35 is held against turning.

' ing throughout the periphery per end of the-keyway 38 which terminates short of the upper end of the bushing so that the core member has a close fit in the bushupper end of the bushing.

The core member 35 is fixed to the upper end of a vertically disposed rack 41 which'is guided for vertical movement in the frame and which is engaged by a pinion 42 fixed to a transverse shaft 43 which may be turned manually to raise or lower the core member.

The main mold member 44 is fixed to the upper ends of vertically disposed racks 45 which are guided for vertical movement in the frame 30 and which are engaged by pinions 46 fixed to a transverse shaft47, one end of which projects to the outside of the frame and has a handwheel 48 attached thereto by means of which the shaft may be turned to actuate the racks 45 and =raise or lower the main mold member. The main mold member 44 has a cavity 49 formed therein which is coaxial with the core member 35 and which conforms to the exterior surface of the casting throughout the extent thereof.

The cavity 49 has an enlarged lower end 50 which fits closely over the projecting upper end portion of the bushing 32 and the bottom inwhieh the base flange of the casting is formed. The core member 35 fits closely within the upper end portion of the bushing 32 so (that the bushing serves to close the lower end of the casting cavity. At the upper end of the main mold member 44, there is formed an upwardly tapering gate 52. which is cpaxial with the casting cavity in which there is formed an upwardly tapering sprue which will permit the mold member to be moved vertically out of contact with the casting formed in the mold. The gate, if desired, may be formed in a metal insert 53' which fits in a counterbore in the top of the mold member 44 with its lower end resting upon the shoulder 54 at, the lower end of the counterbore. The insert 53 may be provided with a peripheral groove forming an annular air space 55 between the insert and the body of the mold member, which serves to lessen I otherwise (would e, thereby insuring an unthe heat conductivity between the insert and the body of the mold-member so that the chillingof the s'rueis less rapid than it impeded flow of molten metal through the gate into the casting cavity until the cavity- 1 is completely filled. a

f In both modifications above described, the

formed against the smoothuninterrupted surface of a cavity formedin a single mold thereof at the member thereby eliminating any seam or fin such as formed between separable mold sections. K

Furthermore absolute uniformity with respect to the exterior dimensions of the casting is insured since all castings are formed against the same continuous surface,

In addition the construction and operation of the mold is. simplified, the mold comprising fewer parts and less complicated actuating mechanisms.

Furthermore it is to beunderstood that the particular form of apparatus shown and described and the particular procedure set forth, are presented for purposesof explanation and illustration and that various modifications of said apparatus and procedure ing cavity opening downwardly, said mold section being further recessed to define a sprue cavity tapering upwardly from said casting cavity, guided means for moving said mold section upwardly out of, and downwardly into, molding position on said support, a permanent core cooperating with said support and defining the interior of said casting cavity, and meansfor causing relative vertical movement between said core and a casting whereby freezing of a casting on the core may be prevented.

' 2. In a permanent mold adapted for casting substantially cup-shaped articles from aluminum alloys and the like, in combination, a support, a single mold section defining the outer surface of a cup-shaped casting cavity opening downwardly, said'mold section being further recessed to define a sprue cavity tapering upwardly from the apex of said casting cavity, the portion of the' mold section defining said sprue cavity being, provided with an air space to reduce the rate of freezing of the sprue metal, means for moving said mold section upwardly out of and downwardly into predetermined molding position on said support, a permanent core carried by said support" and defining the interior of said casting cavity, and means cooperable with the periphery ofthe casting and actuable upwardly to raise said casting off the core to prevent freezing of the castingonto said core. x

3. In a permanent mold adapted for casting substantially cup-sh aped'articles from aluminum alloys and the like, in combination, a support, a single mold section defining the outer surfs. re of a cup-shaped casting cavity opening downwardly, said mold section being further recessed to define a sprue cavity taperinguupwardly from the apex of said casting cavity, a raised mold centering portion on said support for accurately positioning the mold section in predetermined molding position, means for moving said mold section upwardly out of and downwardly i'nto predetermined molding position in cooperative relation with saidmold centering portion on said support, a permanent core arranged to be moved upwardly into molding position within said casting cavity and to be withdrawn downwardly therefrom, means for limiting the extent of upward movement of said core into said casting cavity, said mold centering portion being arranged to cooperate with and support the lower edges of the casting during the withdrawal of the core.

In testimony whereo f I affix my signature.

, EVERETT G. FAHLMAN.

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