METHOD FOR PRODUCING COMPRESSION-MOLDED ARTICLES

• US 3,720,738 A
• Filed: 12/09/1969
• Issued: 03/13/1973
• Est. Priority Date: 12/09/1969
• Status: Expired due to Term

• Current Assignee: Edmund E. Munk
• Original Assignee: Edmund E. Munk
• Inventors: Munk, Edmund E.
• Primary Examiner(s): White, Robert F.
• Assistant Examiner(s): Hall, J. R.
• Application Number:
  US04/883,432
• Time in Patent Office: 1,190 Days
• Field of Search: 264/109,297,37 18/16F,3FH,3GH,3GQ,3GS 25/103 249/104,105,108
• US Class Current: 264/37.28
• CPC Class Codes: B27N 5/00 Manufacture of non-flat articles
• CPC Class Codes: B30B 15/302 Feeding material in particulate or plastic state to moulding presses

Abstract

A method of producing molded articles from a mixture of comminuted material and binder in which the mixture is dropped at a substantially uniform rate onto a filling gate which is provided with at least one aperture having a lower outlet end in vertical alignment with the open end of at least one compartment. At least one wall defining the aperture extends outwardly and upwardly inclined with respect to the outlet end so that the mixture dropping on the inclined wall is intercepted and slides down the inclined wall into a portion of the compartment adjacent thereto so that this portion of the compartment will receive a greater quantity of the mixture than the remainder thereof. The principle may also be used in a mold having a plurality of compartments of different depths which have to be filled substantially to the same upper level. The thus filled mold is then placed in a press into which the mixture is compressed to a solid article which is thereafter removed from the mold.

Claims

1. A method of molding a mixture of comminuted fibrous material and a binder in a mold having separate compartments, each having an open upper end and said compartments having different depths so as to receive different amounts of said mixture for molding articles of different thickness within said compartments of said mold, said method comprising the steps of dropping said mixture from above said mold at a substantially uniform rate of distribution through apertures having an upper inlet and a lower outlet, with each of said outlets positioned over the upper open end of a respective compartment, the ratio of cross sectional area of the upper inlet to the corresponding lower outlet of said apertures being greater for a compartment having a greater depth than for a compartment having a lesser depth whereby a greater amount of said mixture being dropped over an aperture of greater cross sectional upper inlet area is directed through said aperture to said lower outlet and into a compartment having a greater depth, while a smaller amount of said mixture being dropped over an aperture of smaller cross sectional upper inlet area is directed through the corresponding lower outlet into a compartment of lesser depth;

moving the thus filled mold into a press;

compressing in said press said mixture in each compartment so as to form a solid article therein; and

removing each article from said mold.

2. A method as defined in claim 1, wherein a given compartment defines a mold cavity having at least one portion of greater depth than the remainder of said mold cavity, And wherein said greater amount of said mixture dropping through said greater upper inlet area of said aperture is directed to said portion of greater depth of said mold cavity.

3. A method as defined in claim 1, wherein the cross sectional area of the lower outlet of each aperture matches and is aligned with the open upper end of a respective compartment.

4. A method as defined in claim 1, wherein the upper inlets of said apertures are spaced from each other and including the steps of collecting that part of the dropped mixture which does not fall vertically into said apertures in chambers surrounding said apertures, and removing the mixture from said chambers while the mold is moved into the press.

5. A method of simultaneously producing a plurality of molded articles of a mixture of comminuted fibrous materials and a binder, comprising the operations of filling at least two compartments of a mold having open upper ends and different depths with said mixture to a substantially uniform upper level by first covering at least a part of said mold with a filling gate having at least two apertures defined by lateral walls and each having an open upper inlet end and an open lower outlet end, said outlet ends having the same sizes and shapes as, and being in vertical alignment with, said upper ends of the walls of said compartments, at least one of said walls of said gate aperture above the deeper mold compartment being inclined so that its inlet end is larger than its outlet end, and then moving a filling apparatus and said mold including said gate relative to each other so that said filling apparatus passes at least once over said gate while said filling apparatus dispenses said mixture at a uniform rate of distribution in a direction substantially transverse to the direction of said relative movement, whereby said compartments receive said mixture which drops vertically from said filling apparatus through said gate apertures and said deeper compartment additionally receives that part of said mixture which drops upon and slides downwardly along said inclined wall so as to compensate for the difference in depth between said compartments, then moving said mold without said gate into a press, then simultaneously compressing said mixture in both of said compartments to form solid articles of different heights, and then removing said articles from said compartments.

6. A method as defined in claim 5, in which during the relative movement between said filling apparatus and said mold including said gate while said filling apparatus dispenses said mixture on said gate and through said apertures the excess of said mixture which does not fall vertically into said gate apertures and on said inclined wall is collected on said gate and in chambers surrounding said gate apertures and having inner walls forming said walls of said apertures, and further comprising the steps of pivoting said gate about a horizontal axis to an upside-down position when said mold is moved away from said gate and into said press so as to remove said excess mixture from said gate and said chambers, and returning said excess mixture to said filling apparatus.