EP-4735359-A1 - PLACEMENT OF EJECTOR PIN MARKS ON A CONVEYOR BELT MODULE TO IMPROVE CONTACT WITH A NOSEBAR

Abstract

A conveyor belt module and method of making a conveyor belt module through injection molding provide a smooth, uniform nosebar-contacting surface on an underside of the module that is free from ejector pin marks created during the injection molding process. The conveyor belt module includes ejector pin marks only on surfaces that are recessed from the nosebar-contacting surfaces.

Inventors

• MACLACHLAN, GILBERT J.

Assignees

• Laitram, L.L.C.

Dates

Publication Date

20260506

Application Date

20240617

Claims (16)

1. 1. A conveyor belt module, comprising: a laterally-extending body having a top conveying surface and an opposite body bottom surface; a first set of hinge elements extending longitudinally from a first end of the body, the first set of hinge elements including a first hinge bottom surface between the body and a point longitudinally inwards of a center of the hinge elements; a second set of hinge elements extending longitudinally from a second end of the body, the second set of hinge elements including a second hinge bottom surface between the body and a point longitudinally inwards of a center of the hinge elements, wherein the body bottom surface, first hinge bottom surface and second hinge bottom surface define a nosebar-contacting surface; and a plurality of ejector pin marks formed on surfaces that are recessed from the nosebar-contacting surface, such that the nosebar-contacting surface is devoid of ejector pin marks.
2. 2. The conveyor belt module of claim 1, wherein the first set of hinge elements includes at least one drive hinge element including a drive pocket and a first ejector pin mark is formed on a top wall of the drive pocket.
3. 3. The conveyor belt module of claim 2, wherein a second ejector pin mark is formed in a top wall of a half drive pocket formed at a first side of the module.
4. 4. The conveyor belt module of claim 3, wherein a third ejector pin mark is formed in a top wall of a half drive pocket formed at a second side of the module.
5. 5. The conveyor belt module of claim 1, wherein the body tapers longitudinally from the top conveying surface to the opposite bottom surface.
6. 6. The conveyor belt module of claim 5, wherein the opposite bottom surface is a concave curve.
7. 7. The conveyor belt module of claim 5, wherein the body has a shaped front edge and a shaped rear edge.
8. 8. A conveyor belt module, comprising: a laterally-extending body having a top conveying surface and an opposite bottom surface; a first set of hinge elements extending longitudinally from a first end of the body, the first set of hinge elements including a first central hinge element forming a drive pocket open to a bottom of the module; and a first edge hinge element forming a half drive pocket open to both the bottom of the module and a first side edge; a second set of hinge elements extending longitudinally from a second end of the body, and a plurality of ejector pin marks formed only on surfaces within a drive pocket and a half drive pocket.
9. 9. The conveyor belt module of claim 8, wherein a first ejector pin mark is formed on a top wall of the drive pocket on the first central hinge element.
10. 10. The conveyor belt module of claim 8, wherein a second ejector pin mark is formed on a top wall of the half drive pocket.
11. 11. The conveyor belt module of claim 10, wherein the first set of hinge elements further comprises a second edge hinge element forming a half drive pocket open to the bottom of the module and a second side edge, wherein a third ejector pin mark is formed on a top wall in the second edge hinge element.
12. 12. The conveyor belt module of claim 8, wherein the conveyor belt module has a nosebar-contacting surface that is devoid of ejector pin marks.
13. 13. A method of making a conveyor belt module, comprising the steps of: providing a mold defining the module, including a body having a top conveying surface and an opposite bottom surface, a first set of hinge elements extending longitudinally from a first end of the body and a second set of hinge elements extending longitudinally from a second end of the body, the body bottom surface and portions of bottom surfaces formed by the first and second sets of hinge elements defining a nosebarcontacting surface; injecting molten plastic into the mold to form the module; cooling the molten plastic to harden the module; and ejecting the module from the mold using ejector pins, such that the ejector pins only push against recessed surfaces of the module that are recessed from the nosebar-contacting surface.
14. 14. The method of claim 13, wherein the recessed surfaces are formed in top walls of drive pockets formed in the first set of hinge elements.
15. 15. The method of claim 14, wherein a first recessed surface is formed in a central drive pocket and a second recessed surface is formed in a half drive pocket at a first side edge of the module.
16. 16. The method of claim 15, wherein a third recessed surface is formed in a half drive pocket at a second side edge of the module.

Description

Placement of Ejector Pin Marks on a Conveyor Belt Module to Improve Contact with a Nosebar Related Applications The present application claims priority to US Provisional Patent Application Serial Number 63/523,435, filed June 27, 2023 and entitled "Placement of Ejector Pin Marks on a Conveyor Belt Module to Improve Contact with a Nosebar", the contents of which are herein incorporated by reference. Field of the Invention The present invention relates to modular plastic conveying technology. More specifically, the present invention relates to injection-molded conveyor belt modules and the placement of ejector pin marks on the modules to facilitate operation of the conveyor belt. Background Modular plastic conveyor belts are widely used in various industries to convey products. Modular plastic conveyor belts are constructed of a series of rows of side-by-side belt modules. Hinge elements along opposite ends of each row interleave with hinge elements of consecutive rows. A hinge rod inserted in the interleaved hinge elements connects the rows together at hinge joints into an endless conveyor belt loop. Modular plastic conveyor belts are generally formed by an injection molding process. Injection molding of conveyor belt modules often involves the use of ejector pins to push the molded module from the mold. Ejector pins leave a mark on the module, and may be undesirable, because they create a nonuniform surface. In particular, the existence of ejection pin marks on the bottom surface of a module creates difficulty when the module goes around a nosebar, as the uneven surface created by the ejector pin marks creates vibrations, uneven wear and other undesirable effects. Summary An injection-molded conveyor belt module locates ejector pin marks on surfaces that do not contact a nosebar. Ejector pins push against a surface in drive pockets on the module during ejection from a mold to form the ejector pin marks in a recessed area. A nosebarcontacting bottom surface of the module is smooth and free of ejector pin marks. According to one aspect, a conveyor belt module comprises a laterally-extending body having a top conveying surface and an opposite body bottom surface, a first set of hinge elements and a second set of hinge elements. The first set of hinge elements extend longitudinally from a first end of the body and include a first hinge bottom surface between the body and a point longitudinally inwards of a center of the hinge elements. The second set of hinge elements includes a second hinge bottom surface between the body and a point longitudinally inwards of a center of the hinge elements. The body bottom surface, first hinge bottom surface and second hinge bottom surface define a nosebar-contacting surface. A plurality of ejector pin marks are formed on surfaces that are recessed from the nosebarcontacting surface, such that the nosebar-contacting surface is devoid of ejector pin marks. According to another aspect, a conveyor belt module comprises a laterally-extending body having a top conveying surface and an opposite bottom surface, a first set of hinge elements extending longitudinally from a first end of the body and a second set of hinge elements extending longitudinally from a second end of the body. The first set of hinge elements includes a first central hinge element forming a drive pocket open to a bottom of the module and a first edge hinge element forming a half drive pocket open to both the bottom of the module and a first side edge. A plurality of ejector pin marks are formed only on surfaces within a drive pocket and a half drive pocket. According to another aspect, a method of making a conveyor belt module comprises the steps of providing a mold defining the module, injecting molten plastic into the mold to form the module, cooling the molten plastic to harden the module and ejecting the module from the mold using ejector pins. The mold defines a module having a body having a top conveying surface and an opposite bottom surface, a first set of hinge elements extending longitudinally from a first end of the body and a second set of hinge elements extending longitudinally from a second end of the body. The body bottom surface and portions of bottom surfaces formed by the first and second sets of hinge elements define a nosebarcontacting surface. The ejector pins only push against recessed surfaces of the module that are recessed from the nosebar-contacting surface. Brief Description of the Drawings FIG. 1 is an isometric top view of a conveyor belt module according to an embodiment of the invention; FIG. 2 is an isometric bottom view of the conveyor belt module of FIG. 1; FIG. 3 is a cross-sectional view of the conveyor belt module of FIG. 1 through line 3 — 3; FIG. 4 is a side view of a portion of a conveyor belt composed of conveyor belt modules of FIG. 1 going over a nosebar in a conveyor system; FIG. 5 is a bottom view of a portion of the conveyor belt module of FIG. 1 highlighting a n