Plastic conveyor belts and modules with lateral channels

[0001] The invention relates to mechanically driven conveyors and especially to plastic modular conveyor belts having transverse channels formed in the bottom surface of the belt for guiding cleaning liquids and waste to the edges of the belt.

[0002] Plastic modular conveyor belts are widely used in the meat and poultry industry and are used to transport raw meat through processing stations. The tapes are made of many rows of tape modules next to each other. The hinge ears are positioned along the opposite edges of each row of modules with offset from the hinge ears of the next row of modules. Hinged pins inserted into aligned holes in the hinges ears connect rows of modules with hinged joints, forming a belt loop without end of the conveyor.

[0003] US 4 213 527 Lapeyere describes the conveyor belt module depicted in this patent in Fig. 10 according to the removable part of claim 1, wherein the module has an upper surface 80D with three same ridges and depressions located from the first edge to the other edge of the module body , forming a wavy surface that supports the bottom surface of the transported object.

[0004] To meet USDA sanitary requirements, the plastic modular conveyor belt must be able to be cleaned. Hinged joints and drive structure on the inside surface of the belt loop are particularly vulnerable to the accumulation of fat, dirt and waste. Water sprays are usually positioned in such a way that they direct water and cleaning liquids towards the bottom surface of the belt whenever the hinge joint opens by sliding around the circumference of the driving or tensioning sprocket. But when the belt moves to the lower return path, the waste can go back to the hinge joints because the inner surface of the belt is then up. This is especially true for tapes having a generally continuous construction with a small open area.

[0005] Thus, there is a need for an easy-to-clean plastic modular conveyor belt.

Summary [0006] This need and other needs are met by the conveyor belt module according to claim 1, and by the modular conveyor belt according to claim 3.

Brief Description of the Drawings [0007] The characteristics and solutions of the invention as well as its advantages will become more apparent upon reading the following description, the appended claims and the accompanying drawings, in which:

Fig. 1 is an isometric view of a conveyor belt module with the features of the invention, Fig. 2 is a side view of the module of Fig. 1 and Fig. 3 is an isometric view of a fragment of a conveyor equipped with a belt composed of the modules of Fig. 1.

Detailed Description [0008] A plastic conveyor belt module 10 with the features of the invention is shown in Figures 1 and 2. The module body 12 extends longitudinally from its first end 14 to its second end 15. The longitudinal direction is the direction of belt feed because such a module forms part of the modular conveyor belt. The module body extends across the belt from its first edge 16 to its second edge 17. In thickness, the module body extends from the transport surface 18, on which the transported articles are moved, to the opposite surface 19. The hinge structure is represented in the form of lugs 20, which are located along the module body and protrude past the first and second ends of the module body. The outer parts 22 of the hinge ears are wide and form a continuation of the transport surface. The hinge ears narrow towards their narrow portion 23 adjacent to the opposite surface of the strip. As a result, the hinge pin arranged in the holes 24 is accessible for inspection or cleaning. The hinge ears located at one end of the module body are laterally offset from the hinge ears located at the other end of the module body. The recesses 26 between consecutive module hinge ears have a dimension such that the module hinge ears in an adjacent row of conveyor belt modules fit between them.

[0009] The surface 19 of the module body opposite the transport surface is a shaped surface. The two transverse recesses 28, 29 formed in the shaped surface extend from one edge of the module body to its other edge. The ends of the recesses are open, not closed by any structural element on the edges of the module body. The depressions are preferably arched or curved in cross-section, without sharp corners in which waste could accumulate. The ridge in the form of a rod 30 located between the recesses divides the shaped surface into the first and second parts 32, 33. The rod can be a driven rod, absorbing the driving force from the chain wheel or from the driving drum, or it can be used to increase the flexural strength of the module body, or it can improve the overall strength of the module. Transverse ridges 34, 35 are formed in the shaped surface delimiting depressions close to the first and second ends of the module body and to the hinge ears. These ridges act as barriers, preventing water, liquids and waste, along the transverse channels formed by the cavities, from getting into the hinges ears. These ridges close to the first and second ends of the module body are not as high as the middle ridge 30.

[0010] The shaped surface 19 can be described mathematically. The profile of the shaped surface is determined by the distance d between the shaped surface and the plane 31 parallel to the longitudinal direction and to the transverse direction, which is located between the transport surface and the shaped surface, and therefore in each transverse position the value d (x) is a mathematical function whose value changes in the longitudinal direction x (in the direction of belt movement). This function has a first maximum M1 halfway between the first and second ends of the module body, and the second and third maxima M2, M3 located between the first maximum and the first or second end of the module body. Thus, the function d (x) of the profile also has first and second minima m1, m2 located between maxima. The second and third maxima M2, M3 preferably have the same size, as well as the minima m1, m2 have the same size, forming symmetrical channels on both sides of the middle ridge 30. The first maximum M1 representing the middle bar is greater than the second and third maxima M2, M3 in terms of their value. Thus, the middle ridge or rod 30 is higher than the side ridges 34, 35.

[0011] The modules are preferably made of polymer materials, for example polypropylene, polyethylene, acetal or composite polymers in the injection molding process. Conveyor belt modules made of plastic in this way are available from Intralox, LLC, Harahan, Louisiana, USA.

[0012] The advantages of making the conveyor belt using the modules shown in Figs. 1 and 2 are shown in Fig. 3. The belt 36 is made of many rows of 38 modules placed side by side. Modules of various widths are used to make a tape with a pattern similar to a brick wall. But alternatively wide modules could be used with the width covering the entire width of the tape. The rows of modules are connected to each other by hinge pins 40 located transversely to the belt in the passages formed by aligned holes in the adjacent ears of the hinges of adjacent modules. The belt transports articles placed on the transport surfaces of 18 modules along the upper portion 42 of the conveyor bearing surface. The belt is driven by means of chain wheels 44 mounted on a drive shaft 46 located at the end of the bearing surface. The recesses 47 on the periphery of the sprockets work with the transverse rods of the 30 belt modules and drive the belt. The belt is cleaned with a portable or fixed cleaning system 48 that directs water or cleaning liquid to the inner shaped surface of the belt, especially near the sprockets. The belt moves around the sprockets and moves from the part of its path constituting the bearing surface to its return part 50. Along the return portion, the shaped surface 19 of the tape is all directed upwards. One or more spray nozzles 52 direct water 53 over the entire width of the shaped surface of the belt, rinsing waste from its entire inner surface. The recesses 28, 29 in each module are parallel to the recesses in the other modules in the same row of belt modules, forming continuous channels located across the belt. The channels are open at their ends and are not obscured by any structural elements on the edges of the tape. Waste flows from the edges of the belt as shown by arrows 54. Ridges 34, 35 and the middle bar restrict the flow in these channels from the side and prevent the waste from reaching the hinged joints between the modules.

[0013] Although the invention has been described in terms of its preferred version, other versions are also possible. For example, belt modules do not need to have a central driven bar, as in the example version described. In another example, one or more than two transverse channels may be formed in the shaped surface of the module. Thus, as suggested by these few examples, the scope of the claims is not understood to be limited to the preferred version described in detail.