Mold base system
OwnerCharles Ondrejkainventor
Life of this patent
Estimating the term…
Abstract
A mold base system for injection molding machines comprises two cast mold bases each with interior lugs. The lugs of each mold base removeably hold an insert. The inserts are machined to define a cavity that is the negative of the part to be molded. The inserts can be changed to suit different parts without changing the mold bases, which can stay on the injection molding machine indefinitely. Ribs connect the lugs to the mold base outside walls. Two ribs and an outside wall define a pocket that provides access to an insert. The ribs are notched to enable coolant lines to be routed without interference inside the mold base. The mold base system further comprises an ejector plate and a cap. The cap is changeable to suit different configurations of the ejector pins without changing the ejector plate.
Claims38
A mold base system comprising:
- a. first and second mold bases each comprising:
- i. a plurality of outside walls having respective top and bottom surfaces;
- ii. a floor;
- iii. a plurality of lugs upstanding from the floor and arranged to form the corners of a selected geometric shape that defines a perimeter;
- and
- iv. at least one rib between each lug and an associated outside wall;
- b. an ejector housing comprising:
- i. a central wall, and a pair of side walls fastened to the bottom surface of the first mold base;
- and
- ii. a pair of columns upstanding from the central wall;
- c. an ejector plate guided on the ejector housing columns for sliding toward and away from the first mold base;
- d. a cap joined to the ejector plate;
- and
- e. a plurality of ejector pins each having a head captured between the ejector plate and the cap, and a shank that is located inside the geometric shape periphery defined by the mold base lugs, the ejector pin shanks being capable of entering an insert that is removeably holdable in the first mold base lugs.
A mold base for use with an injection molding machine to mold a selected part comprising:
- a. a plurality of walls arranged in a generally rectangular shape having four corners;
- b. a plurality of lugs inside the walls and arranged to form the corners of a selected geometric shape and size, the lugs being capable of removably holding an insert with a surface that conforms to a portion of the selected part;
- c. a plurality of ribs each connecting a respective lug with a selected wall;
- and
- d. a floor between each corner and an associated lug.
A method of injection molding a first selected part comprising the steps of:
- a. providing first and second inserts each having respective multiple outsides, and contoured surfaces that cooperate to form the outline of the first selected part;
- b. providing first and second mold bases;
- c. removeably holding the first insert in the first mold base, and removeably holding the second insert in the second mold base;
- d. fastening the first mold base to an ejector housing, and mounting the ejector housing to the injection molding machine;
- e. mounting the second mold base to the injection molding machine;
- f. closing the injection molding machine and thereby closing the mold bases and the first and second inserts;
- g. injecting plastic material between the first and second inserts contoured surfaces and thereby making the first selected part;
- and
- h. opening the injection molding machine and the mold bases and removing the first selected part from the first and second inserts.
In combination with first and second inserts with respective contoured surfaces that cooperate to define the outside of a selected part,
- first and second mold bases that removeably hold the first and second inserts, respectively, each mold base comprising a wall that defines an enclosed interior;
- a pair of lugs in the interior that removeably hold a selected one of the inserts and that are located on the periperhy of a selected geometric shape;
- at least one rib connecting each lug with the wall;
- and a floor between each lug and the wall.
Dependencies are inferred from the claim text.