One-Piece Weighing Funnel Molding Apparatus and Process

Abstract

An improved molding process for molding weighing funnels. The molding process involves forming one or more mold cavities wherein each mold cavity comprises an upper cavity portion in an upper mold section and a lower cavity portion in a lower mold section. A two piece core comprising an upper core and lower core are positioned in close proximity to one another. The lower molding section is moved upward to place it in close proximity to the upper molding section to form a mold cavity while the lower core is simultaneously moved into the mold cavity into close proximity with the upper core. Plastic is injected into the mold cavity using hot runner technology to form a weighing funnel. After the weighing funnel is formed, the lower molding section is moved downward while the lower core is simultaneously retracted from the mold cavity. A robotic arm is used to remove finished product from the mold.

Claims

1. A method for molding a weighing funnel comprising: forming a plurality of mold cavities, wherein each mold cavity comprises an upper cavity portion in an upper mold section and a lower cavity portion in a lower mold section, positioning, within each mold cavity, an upper core and a lower core, injecting plastic into the mold cavities, molding a plurality of weighing funnels, moving the lower mold section downward, retracting each lower core from the mold cavity, and removing each weighing funnel using a robotic arm.

2. The method of claim 1 wherein the upper cavity portion includes a flat surface near the uppermost portion of the upper cavity.

3. The method of claim 1 wherein moving the lower mold section downward and retracting each lower core from the mold cavity happens simultaneously.

4. The method of claim 1 wherein the robotic arm includes suction cups.

5. The method of claim 1 wherein a needle valve hot runner system is used to inject plastic into the mold cavities.

6. The method of claim 1 wherein the lower core is operatively connected to a pulling mechanism that facilitates movement of the lower core relative to the interior of the mold cavity.

Description

DESCRIPTION OF THE DRAWINGS

[0009] To allow for a fuller understanding of the present disclosure, it will now be described by way of example, with reference to the accompanying images and drawings in which:

[0010] FIG. 1 illustrates a side-view of the molding apparatus, in accordance with aspects of this disclosure;

[0011] FIG. 2 illustrates a bottom view of the upper section of the molding apparatus of FIG. 1;

[0012] FIG. 3 illustrates a top view of the lower movable section of the molding apparatus of FIG. 1, in accordance with aspects of this disclosure;

[0013] FIG. 4 is a top view of the lower movable section of the molding apparatus of FIG. 1 in accordance with aspects of this disclosure;

[0014] FIG. 5 is a perspective view of the fixed core of the molding apparatus of FIG. 1, in accordance with aspects of this disclosure;

[0015] FIG. 6 illustrate the mold cavity in the lower section for forming the upper portion of the product, in accordance with aspects of this disclosure;

[0016] FIG. 7 illustrates the movable core of the molding apparatus of FIG. 1, in accordance with aspects of this disclosure;

[0017] FIG. 8 illustrates the molding apparatus of FIG. 1, in accordance with aspects of this disclosure.

DETAILED DESCRIPTION

[0018] While this invention is susceptible of embodiments in many different forms, there are shown in the drawings and will herein be described in detail example embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. In the following description of various example structures according to the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example devices, systems, and environments in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, example devices, systems, and environments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.

[0019] Also, while the terms upper, lower, and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures or the orientation during typical use. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of structures in order to fall within the scope of this invention. Also, the reader is advised that the attached drawings are not necessarily drawn to scale.

[0020] In general, this disclosure relates to a molding apparatus and process used to mold plastic weighing funnels. Molding weighing funnels presents a challenge for injection molding because a weighing funnel has an opening that is smaller than the inner cavity. This poses a challenge for how to release a mold core from an opening that is smaller than the core. Applicant has developed an improved apparatus and molding process that provides for increased productivity and improved product quality.

[0021] Referring to FIG. 1, the molding apparatus includes an upper mold section 10 and a lower mold section 12, an upper core 30, a lower movable core 32, and pulling mechanism 42 operably connected to the lower movable core 32.

[0022] Upper section 10 is preferably rectangularly shaped. Upper section 10 includes at least one guide hole 16 for receiving a sliding bar 14. Most preferably, upper section 10 includes four guide holes 16 as shown in FIG. 2. Upper section 10 includes an upper mold cavity 20 sized and configured to form the outer bottom shape of a weighing funnel. Preferably, upper section 10 includes at least two upper mold cavities 20. Preferably, the uppermost portion of the upper mold cavity 20 preferably includes a flat surface 21. By including a flat surface 21 near the uppermost portion of the upper mold cavity 20, the finished product will include a flat surface that may be utilized by a robotic arm to remove a finished product from the mold. Preferably, upper section 10 is to sliding bar 14 such that movement of the upper section 10 along the vertical axis of sliding bar 14 is minimized. Most preferably, upper section 10 is fixed so that it does not move along the vertical axis of sliding bar 14.

[0023] As shown in FIGS. 1 and 6, lower section 12 includes a lower mold cavity 40 sized and configured to form the outer upper shape of a weighing funnel. Preferably, lower section 12 includes at least two lower mold cavities 40 as shown in FIG. 6. Lower section 12 includes one or more guide holes for receiving sliding bars 14. Lower section 12 is movable along a vertical axis defined by the sliding bars 14 in a direction towards or away from upper section 10. The lower section 12 may be moved upward into working engagement with upper section 10 such that upper mold cavity 20 and lower mold cavity 40 mate to form a product mold cavity. Preferably, support 38 is operably connected to lower section 12.

[0024] As shown in FIG. 2, upper section 10 is connected to a needle valve hot runner system 18 that injects plastic material into the product mold cavity formed by the upper mold cavity 20 and lower mold cavity 40. Suitable plastics for the weighing tunnel include polypropylene, polyethylene, and polystyrene.

[0025] As shown in FIG. 1, the present invention utilizes a two piece core for each molded funnel piece. As best shown in FIG. 5, upper core 30 is sized and configured to form the interior surface of the lower portion of a weighing funnel. Preferably, upper core 30 is fixed to support 38 and the upper core 30 is movable only in the vertical direction along the axis defined by the sliding bars 14. As best shown in FIG. 7, the lower core 32 is sized and configured to form the interior surface of the upper portion of a weighing funnel. A finished product 50 is also shown in FIG. 7. Upper core 30 and lower core 32 are operationally connected to support 38 and lower section 12 such that upper core 30 and lower core 32 are positioned within upper mold cavity 20 and lower mold cavity 40 when plastic is injected into the mold.

[0026] Lower core 32 is connected to a pulling mechanism 42 which allows the lower core to be moved in an inward or outward direction (i.e. horizontal) generally perpendicular to the vertical axis defined by sliding bars 14. The direction of movement of pulling mechanism 42 is shown by arrow 60 in FIG. 1. During molding, the pulling mechanism is moved inward (to the right in FIG. 1) such that the lower core 32 is brought into working relationship with the upper core 30. Moving the pulling mechanism 42 outward away from the product mold cavity causes the lower core 32 to release from a molded weighing funnel. The pulling mechanism may include one or more rods, shafts, or like structure attached to a support connected that is connected to the lower core that facilitates the movement of the lower core in a direction towards (into) and/or away from (out of) the mold cavity. The pulling mechanism preferably facilitates movement of the lower core so that the lower core may move completely out of the mold cavity. Movement of a portion of the lower core out of the mold cavity is also within the scope of the invention.

[0027] The new apparatus may be used to improve the method of manufacturing weighing funnels. The molding process comprises (a) forming a plurality of mold cavities, wherein each mold cavity comprises an upper cavity in an upper mold section and a lower cavity in a lower mold section, (b) positioning, within each mold cavity, a lower core in operational proximity with an upper core, (c) injecting plastic into the mold cavity through a needle valve hot runner, (e) molding a plurality of weighing funnels, (f) moving the lower mold section downward, (g) removing each lower core from the weighing funnels, and (h) removing each weighing funnel from the mold using a robotic arm. Preferably, the lower mold section and the upper core move into molding position simultaneously, Preferably, the lower mold section moves downward at the same time the lower core is removed from the weighing funnel. Preferably, the robotic arm 62 removes finished products at the same time the lower mold section moves downward and the lower core is removed. As shown in FIG. 1, the apparatus includes one or more springs 62 positioned between support 38 and lower section 12. Most preferably, the apparatus includes four springs 62, positioned adjacent the corners of support 38. The springs assist in biasing the lower section 12 away from support 38, resulting in the finished product to be moved a few millimeters out of cavity 40 for easier removal by robotic arm 62.

[0028] FIG. 8 illustrates a robotic arm 62 that may be utilized in the invention to remove molded weighing funnels from the apparatus. Preferably, the robotic arm 62 includes suction cups (not shown) that engage a flat surface of each weighing funnel to remove the product from the mold and place it in bin. By using the improved process, the molding process is fully automated and the need for an operator is eliminated, or greatly reduced.

[0029] It is also understood that the systems, methods, and machines described herein may be constructed with similar structural and functional elements having different configurations, including different ornamental appearances. Still other benefits may be recognized by those skilled in the art. Accordingly, while the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the scope of the accompanying claims.