US1896824A

US1896824A - Apparatus for molding

Info

Publication number: US1896824A
Application number: US500617A
Authority: US
Inventors: Mahieu Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-12-07
Filing date: 1930-12-06
Publication date: 1933-02-07
Anticipated expiration: 1950-02-07

Description

Feb. 7, 1933. P. MAHn-:U

APPARATUS FOR yMOLDING Filed Dec. 6, 1930 /v vf NTO R 95m/ M40/F@ Patented Feb. 7, 1233 PATENT oFFica PAUL MAHIEU, oF rARIs. FRANCE APPARATUS non Momma Application led December 6, 1,930, Serial No. 500,617, and in France December 7, 1929.

The present invention has for its object to provide an improved apparatus for molding under pressure and is primarily characterized in that the pressure of the fluid acting on the material to be molded is progressive. s

This essential characteristic obviates the blow holes which generally form in castings made under pressure, due to the fact that the air contained in the mold has insufcient time to escape completely by the joints of the mold or the vents. f

In the process according to the invention, When'the metal is admitted intothe mold, a small regulable pressure is exerted thereon to facilitate merely 'its flow and a highl er pressure is not placedl on the metal until this has suilicientlyrilled the mold. The cast.- y'

' ing taking placeat the beginning under a moderate pressure the air containedin the l 2o mold has the necessary time to escape completely through the vents. Subsequently the high pressure, which may be varied, produces all its advantages. i It makes the metal take up the smallest details of the moldand it coml pensates for shrinkage of the metal, which shrinkage is particularly noticeable in the case of thick parts. y .f

4The annexed figure shows by way of er: ample oneembodiment of apparatus for car- 3o rying out the invention.

In this figure the Crucible v1 contains the metal 2 maintained in a molten state by the hearth 3. The upper opening of the cru-cible closed by a tight cover 4 forms a kind oi air 3 5 bell, damping outrapid variations of pressure. The air 0r other uid under pressure' is admitted through the conduit .8, which is formed with an intake chamber 8 V In the Wall of crucible 1 is formed va si- 40 phon-shaped conduit 9 conducting the metal to 'the union or nozzle 10 receiving the mold.

To obtain progressive increase in the pressure use is made of an expansion or reducing device comprising an expansion chamber 17 closed by a diaphragm 18 which through the rod 19 controls lthe valve Q0 'disposed at the outlet of thev conduit v8. .The pressure regu.

l'ating spring 20 is controlled by the lever 12 and it willbe seen that progressivelower-A ing of this lever causes progressive increase4 of the pressure in 17 and 15. On raising the lever 12 the finger 21 carried by itacts on a valve 22 establishing communication between 15'and 17 and the atmosphere.

ting the metal to descend through the conf` duit 9 to the same level as that in the Crucible. The mold may then be removed and the operation recommenced It is pointed out that applicants device differs from those of the prior art in being substantially automatic. When the valve 2O is opened by a depression of the lever 12, the air enters the Crucible under an initial pressure and When this pressure rises to a Certain point the back pressure in the expansion chamber 17, is exerted on the diaphragml'S,

' which is pressed o'utWard against thev pressure of the spring and automatically closes the valve 20, Ithus allowing the airunder moderate and initial pressure to act on the metal in the Crucible.

`under increase of pressure, is admitted.

When sufficient action 1s deemed to have taken place and an increase This increase of .pressure may be regulated through vthe operation of the lever.,

It is obvious that the meansdescribed above.

4 1. In a molding apparatus oi the character described, a Crucible having a contracted outf i let leading to a mold, a. conduit connected to the crucible for the admission of air under pressure, said 'conduit including an expan-.

sion chamber, an open port in said chamber leading to the Crucible, a valve seating port in said chamber for admitting pressure thereto,

a diaphragm mounted in said chamber opposite said second port, a valve in-'said second port, having a stem connected to said diaphragm and means mounted on the'outside of said chamber, and adapted to exert determinable vamounts of pressure on said diaphragm.

. 2. In a molding apparatus of the character descr'bed,'a crucible having a contracted outpressure, havin letleading to a mold, a conduit connectedV to the cr'ucible for the admission-of air under expansion cham er,` and having a manually operablevalve between said chambers to control the-passage of air from the intake chami ber, and means in a Wall of said expansion chamber for automatically closing said valve when a determined back pressure has' been built up in said expansion chamber.

In testimony whereof I alixmy signature.

an intake chamber-and anV