Conveyor belt modules with embedded rollers retained in the modules

[0001] The invention relates to plastic conveyor belt modules and conveyor belts comprising such plastic modules. [0002] Modular plastic conveyor belts are commonly used to transport various articles. Rolls for accumulating, dividing, sorting, indexing or sliding the product sideways are often placed on the strips. Rollers are also used to reduce friction between the belt and the sliding strips or side rails supporting it. Unidirectional rollers are integrated with conveyor belts by rotating them on a hinged rod connecting subsequent rows of belt modules. Another way is to snap the roller assemblies into the tape modules. Yet another way is forming rollers in the tape modules while forming the modules. But each of these methods has its drawbacks.

[0003] For example, placing rollers on hinged rods usually requires that the hinged eyes be removed first to create a space for the rollers. Because the tension of the tape is initiated in the hinged eyelets, removing a few of them reduces the tensile strength of the tape. In another example, the latch roller assemblies may break. If the latch roller assembly structure breaks, broken parts of the roller assembly may separate from the belt and contaminate the product or cause other damage. In the last example, rolls formed in the module, as part of the injection molding process, require the use of special components in the mold and manual intervention, and manual placement of the rollers during each molding cycle. As a result, the mold is expensive and the service life of the forming device is shortened. In addition, after its formation, the roller with its axis is constantly orientated.

[0004] US 2001/0045346 A1 describes a plastic conveyor belt module in accordance with the preamble of claim 1.

Summary [0005] Said drawbacks are removed thanks to the conveyor belt module according to claim 1.

[0006] The body of the conveyor belt module preferably extends longitudinally from the first end to the second end, and in thickness from the first side to the second side, and the module body comprises first hinged eyes spaced apart along the first end, and second hinged eyes spaced apart from each other along the other end. The arrangement of internal walls in the module body limits the cavity open towards at least one of the first and second sides. The arrangement of internal walls preferably forms a socket located between the first and second sides of the module body in which the roller is located. The retaining ring is welded to the socket, for example by ultrasonic waves, or attached by another method, holding the roller rotating in the cavity.

[0007] Further or alternative preferred features are listed in claims 2 to 16.

[0008] In an embodiment of the invention, the module body comprises an arrangement of inner walls delimiting a generally rectangular recess open towards one or both outer surfaces. The arrangement of internal walls also creates a four-sided socket between the two outer surfaces of the module body. First and second pairs of recesses are formed in the socket. The recesses of each pair are diametrically opposite across the cavity. An axis is placed in the roller hole. The ends of the axles are located in the first pair of diametrically opposite recesses. The four-sided holding ring has a pair of diametrically opposite recesses in a pair of its opposite sides. The retaining ring is seated in the socket. His lugs are located in a second pair of nest cavities. The recesses in the retaining ring cover the ends of the axles, holding the roller in the module body.

[0009] The object of the invention is also obtained thanks to the plastic conveyor belt according to claim 17.

Brief Description of the Drawings [0010] These and other features, forms and advantages of the invention will be better understood from the example, the following description, the appended claims and the accompanying drawings, in which:

Fig. 1 is a view of a fragment of a conveyor belt composed of plastic modules according to the invention, Fig. 2A and 2Bb are perspective views, with parts being apart, of a fragment of one version of the module that can be used in the conveyor belt of Fig. 1, with a roller in longitudinal and transverse arrangement, Fig. 3A is a bottom perspective view of the module according to Fig. 2A, and Fig. 3B is a front view of the module according to Fig. 2A, Fig. 4 is a perspective view of a fragment of the module according to Fig. 2B before welding the ring in its place in the module, Fig. 5 is a view of a fragment of another version of the module in a conveyor belt with spherical rollers that can be used in the conveyor belt according to Fig. .1, Fig. 6A is a perspective view, with these parts apart, of a fragment of the module of Fig. 5 using a welded or glued roller retainer, and Fig. 6B is a perspective view of the module of Fig. 6A, in assembled state, Fig. 7 is a perspective view, with parts extended, the module of Fig. 5, with a roller retainer screwed in, Fig. 8 is a perspective view, with parts apart, the module according to fig. 5, with the latch roller retainer, and fig. 9A is a perspective view, with these parts apart, of the module according to fig. 5, with the roller retainer mounted on the posts, and Fig. 9B is a perspective view of the module of Fig. 9A in assembled condition.

Detailed description [0011] A fragment of the modular plastic conveyor belt with the modules according to the invention is shown in Fig. 1. Tape 20 consists of a series of rows of 22A-D 24 tape modules, 24A short edge modules, 24B long edge modules and 24C middle modules. Although the modules are preferably arranged like blocks, the tape can be formed differently, for example with the only module in a row. Each module extends longitudinally from the first end 26 to the second end 27. The first set of hinged eyes 28 has an arrangement with hinged eyes spaced apart from each other along the first end, and the second set of hinged eyes 29 has an arrangement with hinged eyes spaced apart from each other along the second end. The first set of hinged meshes of one row of modules intertwines with the second set of hinged meshes of the adjacent row. Aligned holes 30 in interlaced hinged meshes form a transverse passage relative to the width of the belt. Hinged rod 32 embedded in the corridor connects successive rows of modules to each other, forming a hinged connector, enabling the belt to rotate around driven sprockets and tensioning return wheels. The tape modules are characterized by rollers 34 mounted in cavities 36 formed in the tape modules. The rollers extend beyond the outer surface 38 of the belt, cooperating with the transported articles in contact with it rollingly (if the outer surface is the transporting surface) or cooperating with low friction with the surfaces supporting the conveyor (if the outer surface is the supported surface of the belt).

[0012] The rollers shown in Fig. 1 are longitudinal rollers and their axis of rotation is transverse to the direction of travel of the belt. The belt could alternatively be constructed with rollers rotating about a perpendicular or oblique axis to that shown in Fig. 1, or with freely rotating rolling balls.

[0013] The belt module 24 according to figure 1 is shown in figure 2A. The module has a body 42, a cylindrical roller 34 mounted on the axis 44 with its opening 35, and a retaining ring 46. The module body has an internal wall system consisting of a first internal wall 48 - generally with a quadrilateral shape with rounded corners. The outer edge 50 of the first wall ends at the first outer surface 52 of the module. Coaxial with the first wall is a second closed wall 49, with an inner diameter smaller than the diameter of the first wall. The arrangement of inner walls delimits the cavity 36 open towards the first outer surface 52 and the opposite second outer surface 53 of the module body. (The term "diameter" and its variations are used herein in the general sense of the distance measured between two points on a closed wall constituting the segment passing through its center. When comparing the "diameters" of two walls, geometrically similar points on each wall must be compared, constituting the geometric ends of the respective "diameters"). The outer edge 54 of the second wall ends on the second outer surface 53 of the module body. In the arrangement of the inner walls, between the inner edges 51, 55 of the two walls, a projection 56 with a lip 58 is formed. On this projection there are pairs of recesses 60, 61. Each visible cavity is supplemented with a diametrically opposite cavity on the opposite side of the wall, which is not visible in Fig. 2A. In each pair of depressions 60 there is an axle supporting the roller in the recess. The retaining ring has a pair of diametrically opposite recesses 64 covering the ends of the axles after inserting the ring into the recess. The ring also has a pair of diametrically opposed projections 66 that fit into the recesses of the module body projection. In this case, the projections of the retaining ring are located in recesses 61 not supporting the roller axis. Thus, the protrusions on the retaining ring and the depressions in the projection of the module body form a locking structure ensuring that the retaining ring and rollers are properly seated in the cavity. After seating the retaining ring in the module body, the roller is retained in the recess and can rotate freely about its axis which is transverse to the longitudinal direction of the module for the roller in the longitudinal arrangement.

The same component shown in Fig. 2A can be used to form a belt module 24 'with a transverse roller, as shown in Fig. 2B. In this example, the axis ends 62 are located in diametrically opposite recesses 61, instead of recesses 62. This effectively orientates the axis longitudinally - perpendicular to the orientation according to Fig. 2A. The holding ring 46 is therefore rotated 90^about so that its protrusions contact the locking recesses 60 instead of the recesses 61 forming a belt module with a transverse roller. Thus, in this version of the tape module, alternative orientations of the roller rotation axis are possible.

A module 24 with a roller in a longitudinal arrangement is shown in detail in Figures 3A and 3B. In this example, the cavity 36 is open to the other outer side 53 - in this case the bottom side - of the module body 42. But it would be possible to close the cavity opening because the roller 34 is recessed inside from the outer side 53. As shown in Figure 3B, the protruding portion 68 of the built-in roller 34 extends outwardly beyond the first outer side 52 - in this case the upper, transporting side cooperating rollingly with the transported articles.

When manufacturing such a module, the module body is first formed of a thermoplastic material, e.g. polyethylene, propylene, acetal or a polymer composite, in particular by injection molding. The formed module is characterized in that the arrangement of internal walls limits the recess open to the outer side of the module. Then the roll is inserted into the recess. The fixture is then placed in the recess, holding the roller rotating in this place. The preferred method of producing these modules is shown in Figure 4. After placing the retainer in the recess, it is welded by ultrasound to the projection or to the socket to which the retainer ring adheres. An ultrasound head 70 having a shape adjacent to the holding ring 46 is brought into contact with the ring. The energy of the ultrasonic waves quickly vibrates the bottom surface of the ring relative to the seat and causes the seat and bottom surface of the ring to melt due to friction. The protuberance formed along the bottom surface of the ring melts and joins the socket. Under down pressure on the head, the breast pushes the shadow deeply into the socket as the convexity on the lower surface of the ring melts until the upper surface 71 of the ring is preferably positioned along the outer surface 52 of the module. An example ultrasonic head for such an operation is made of titanium and provides an amplitude of 90-120 microns at 20 kHz. One of the manufacturers of this type of device is Branson Ultrasonics Corporation of Danbury, Connecticut, USA.

Another version of the module with a built-in roller is shown in Fig. 5. Module 72 is equipped with spherical rollers 74 that can rotate freely in all directions. In this example, the spherical rollers protrude beyond both the upper and lower outer surfaces 76, 77 of the module. Such a module can be produced in various ways.

According to one such method, shown in the version with the spherical rollers according to Figures 6A and 6B, the module 72 has a body 73, a spherical roller 74 and a retainer in the form of a ring 80. The arrangement of the internal walls in the module limits the rounded cavity 82. The arrangement of the walls includes the first a closed rounded wall 84 whose outer edge 86 is located on the first outer surface 78 of the module body. The second closed rounded wall 85 has an outer edge 87 that is located on the opposite second outer surface 79 of the module body. The diameter of the second wall is smaller than the diameter of the first wall. The projection 88, being the seat for the retaining ring, is formed between the inner edges 86 ', 87' of the two walls. Ribs 90 along the second wall support the ball with low friction. Similar ribs 91 are formed on the inner surface of the retaining ring. The ball and retaining ring are placed in the recess. The holder is then ultrasonic welded to the socket, holding the ball in the socket. Epoxy gluing, solvent gluing, electromagnetic welding, and friction welding are alternative methods of connecting the holder to the module body socket.

Figures 7-9 show other fastening methods. In Fig. 7, for example, the first closed wall 94 is provided with a thread that cooperates with the thread 95 on the circumference of the holding ring 96. Roller 74 is thrown into the cavity 98 and the holding ring is screwed. As with the other retaining rings of Fig. 6, the diameter of the center hole in the ring 96 is smaller than the diameter of the rolling path. By covering part of the ball, the retainer holds the ball in the module.

Figure 8 illustrates another fastening method in which the locking slots 100 are formed in the first closed wall 102 of the module body 104 at diametrically opposed locations. The slots have an L-shaped shape and are open toward the outer surface 106 of the module body. A locking recess 108 is arranged at the closed end of each slot. The retaining rings 110 have locking tabs 112 with bumpers 114 that fit into the locking recess at the ends of the slots. After placing the roller 74 in the cavity 116, the retaining tabs are positioned in the L-shaped slots where they are open towards the outer surface. Then the holders rotate clockwise until the tabs on the tabs lock into the locking recesses at the ends of the slots. In this way, as in the screwdriver version, the rollers are held in the recesses but can be removed by unscrewing the holders.

[0014] Another example of a fixing method is shown in Figures 9A and 9B. In this version, the module body 118 has a pair of posts 120 protruding beyond the outer surface 122 of the module body in diametrically opposite locations of the cavity 124. Retaining rings 126 for spherical rollers 74 have diametrically opposite grooves 127 around the periphery of the rings. When the roller and holder are inserted into the recess, the posts fit into the grooves positioning the holder. The top portions of the posts are then flattened or deformed by, for example, heat, pressure, impact or ultrasonic wave energy to form an expanded head 128 blocking the retainer over the roller.

Thus, the invention has been described in several sample versions, but other versions are possible. For example, unlike the rollers shown in the drawings, for example, the spherical rollers are not intended to protrude beyond both outer surfaces of the belt, while the rollers with their axes may protrude beyond both sides. All that is needed is the geometry of the internal walls and the diameter of the rollers changed accordingly. Several different mounting methods in the examples with spherical rollers can also be used for cylindrical rollers.

[0015] Thus, as these some examples suggest, the scope of the claims is not intended to limit the versions described, but is defined by the appended claims.