US1926870A - Multiple mold - Google Patents

Description

Sept. 12, 1933. M. GUYOT 1,926,870

MULTIPLE MOLD Filed June 23. 1930 2 Sheets-Shee. l

er {PUINIIII Patented Sept. 12, 1933 UNITED STATES PATENT OFFICE MULTIPLE MOLD Application `June 23, 1930. Serial No. 462,975

3 Claims.

This invention relates to molds for casting articles from molten metal, and more particularly to molds for simultaneously casting a pair of articles, such as internal combustion engine pistons.

Molds for simultaneously casting a pair of articles are disclosed in my prior Patents No. 1,679,860 and No. 1,729,643. In the type of mold disclosed in these patents a pair of pivoted mold halves are formed with spaced casting cavities communicating with a gatedisposed therebetween, each of the casting cavities being flanked by a pair of riser cavities. The mold halves are secured against separation at their opposite ends by the pivotal connection therebetween and a suitable clamp. In use, the molten metal first comes in contact with the gate and then flows through the feeder channels vinto the casting cavities. As a result, the central portions of the mold halves are heated to a higher temperature than the ends, causing the mold halves to expand unequally and warp. This warping of the molds distorts the casting cavities slightly and interferes with the production of uniform castings. Accordingly, the principal object of this invention is to provide a mold which will overcome this difficulty and which will be lesssubject to Warpage and distortion than those heretofore in use.

Another object of this invention is to arrange the gates, the casting cavities, and the risers in a mold of this type in such a manner as to reduce the quantity of scrap in the resulting casting.

Another object of this invention is to provide a mold of this type in which the cores are located adjacent each other and are spaced from the gate so that the two cores may be simultaneously manipulated.

A further object is to provide an improved connection between the mold halves and the base.

Other objects relating to details of construction and economies of manufacture will appear hereinafter. i' In the accompanying drawings which illustrate a preferred embodiment of the invention:

Figure 1- is a longitudinal vertical section through a mold constructed in accordance with this invention, one of the mold halves being illustrated in elevation. y

Figure 2 is a top plan view of the mold.

Figure 3 is a plan View of an end of the mold sections showing the clamping means.

Referring to the drawings, the numeral 10 designates the base upon which the mold is mounted. Circular openingsll surrounded by depending annular flanges 12 are formed in the base and spaced apart a short distance along the longitudinal center line thereof. A member 13 provided with upstanding pilots 14 is secured to the base by studs 15 with the pilots projecting through the apertures 11.

The base is formed at one end thereof with a lateral ear 16 apertured to pivotally receive a pin 17 projecting from a yoke plate 18. Pivot pins 19 and 20 are carried by the yoke plate 18 and are connected at their upper ends by a second plate 21.

The two mold halves 22 and 23 are pivoted respectively on the pivot pins 19 and 20 for swinging movement over the base 10, and are provided at their free ends with bars 24 and 25 carrying a 70 clamping device for securing the mold halves together. A link 26 is pivoted to the bar 24 and extends laterally past the bar 25. A lever 27 having a cam face 28 is eccentrically pivoted to the end of the link 26 in such a manner that it 75 may be turned into the position shown in Figure 3 so that the cam face 28 bears against the outer surface of the bar 25 and rmly clamps the mold halves together. The meeting surfaces of the mold halves 22 and 23 are provided with depres- 80 sions which form the gate, the risers and the casting cavities, and also with semi-circular recesses 29 which t snugly over the projecting ends of the pilots 14 and position the mold halves with respect to the base and each other. The recesses in the mold halves cooperate to form two main castings cavities 30 and 31 separated by riser 32 and flanked by risers 33 and 34. s

The riser 33 merges into a feeder passage 36 which communicates through a sinuous connecting channel 37 with the gate 38 having an inlet opening 39. The walls of the gate 38, the connecting passage 37 and the feeder 36 converge in such a manner as to provide a passage of decreasing cross sectional area extending from the inlet opening 39 to the point where the feeder passage 36 spreads out vertically to merge with the riser 33. The reverse curve in the connecting channel 37 forms a liquid seal when molten metal is introduced into the inlet passage and serves to retard the-velocity of the molten metal passing therethrough. The feeder 36 and channel 37 are 4curved in such a manner that the molten metal enters the feeder and casting cavities smoothly and at such a velocity that substantially all agitation or splashing of the molten metal is avoided. The liquid seal formed in the channel 37 assists in excluding light impurities from entering the casting cavities. The gate and feedn ing passages are constructed substantially as dispilots 14.

closed and claimed in U. S. Letters Patent No. 1,675,043 issued June 26, 1928 to Allen B. Norton. Main cores of any suitable type are positioned in each casting cavity to form the interior surfaces of the castings. Three part cores are illustrated in the drawings but it is to be understood that any other type, such as five part or seven part cores, might be used. Each core comprises a central member 40 and two side members 41 and 42, which fit together to form the desired shape for the hollow interior of the piston casting. Core pins 46 extend into the casting cavities through removable bushings 47 secured in the mold halves and form the cored out piston pin bosses of the casting. If desired, the mold may be provided with means for simultaneously operating the two core pins on each side, such as disclosed inv my prior Patent No. 1,679,860 referred to heretofore.

Preferably the main core sections of the respective casting cavities are secured together for simultaneous manipulation. For this purpose a connecting bar 48 is bolted to the upper end of the two core members 40 by bolts 49. A handle 50 of any desired type is secured to the bar 48 by a short stud 51. The core members 41 are similarly secured together by a bar 52 and the core members 42 are united by abar 54. If desired, however, each core member may be provided with a handle for independent manipulation.

In operation, the mold halves- 22 and 23 are swung together and clamped in position about the In this movement the mold halves pivot about the pins 19 and 20, and if necessary, move longitudinally relative to each other by pivotal movement of the plater18 on the pin 17. 'Ihe outer core members 41 and 42 are then positioned in the respective casting cavities and the core members 40 are-forced between them to complete the main core assemblies. The core pins 46 are then pushed inwardly through the bushings 47 and the mold is in condition for use. Molten metal is then poured through the inlet opening 39 and flows through the passages 36 vand 37 into the riser 33. The metal then flows into the casting cavity 30, the riser 32, the casting cavity 31 and the riser 34. During this operation, air is forced upwardly out of the cavities through crevices formed by the inter-sections of the core parts and the mold halves. 'The molten metal also flows into openings 55 in the pilots 14 which are closed by serrated plugs 56 to form machining bosses 57 on the piston castings. When the molten metal has solidified the central core sections 40 are removed and the core pins 46 are withdrawn. The outer core sections 41 and 42 are then pushed inwardly and removed and the mold halves are separated, permitting the withdrawal therefrom of the completed casting.

It will be evident that the portions of the mold halves surrounding the gate 34 are heated to a higher temperature than the remainder of the mold halves, since the molten metal first comes in contact with these portions. However, since these portions are adjacent the ends of the mold halves which are clamped together, the tendency toward unequal expansion is restrained and the casting cavities are not distorted. Furthermore, it will be evident that the scrap which must be trimmed from the casting to prepare the pistons for machining consists only of the portions formed by the risers 32, 33, 34 and the feeder passages and gate 36, 37 and 38.

While the foregoing description is necessarily,

of a detailed character in order that the invention may be fully set forth, it is to be understood that the specific terminology is not to be construed and restrictive or limiting, and it is to be further understood that various modications and rearrangements of parts may be resorted to without departing from the scope of the invention as defined in the following claims.

I claim:

1. In a mold, a pair of members having meeting faces recessed to form a pair of casting cavities, a common riser disposedtherebetween, and an independent riser for each casting cavity.

2. In a mold, a pair of members having meeting faces recessed to form consecutively a feeder passage, a riser, a casting cavity, a common riser, and a second casting cavity.

3. In a mold, a pair of members having meeting faces recessed to provide intercommunicating cavities, said cavities being constructed to form consecutively a feeder, a riser, a casting cavity, a second riser, a second casting cavity, and a third riser.

' MARIUS GUYOT.

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