BACKGROUND

[0001] Conveyor rollers are used in a plurality of conveyor applications. In some applications, the failure of a conveyor roller can have significant consequences. It can therefore be desirable to design conveyor rollers in a manner to limit the likelihood of failure. Although known conveyor rollers were satisfactory to a certain extent, there always remains room for improvement.

SUMMARY

[0002] It was found that in certain cases, the likelihood of failure could be addressed by changing the mechanical configuration of components forming the conveyor roller.

[0003] In accordance with one aspect, there is provided a conveyor roller comprising a shaft, a roller body rotatably mounted around the shaft via bearings, an end cap secured to the shaft at each axial end of the conveyor roller, the end cap extending radially between the shaft and the roller body, and a sealing assembly between each end cap and the bearings, the shaft protruding axially from both end caps.

[0004] It was found that in other cases, the likelihood of failure could be addressed by adapting the method of manufacture of the conveyor roller.

[0005] In accordance with another aspect, there is provided a method of making a conveyor roller, the method comprising: applying a mould-release agent on a shaft, the mould-release agent covering at least two filler portions of the shaft axially external to bearing locations and seals on the shaft; pouring a filler to fill a space extending radially between one of the filler portions of the shaft and a radially-inner face of a roller body and axially external to and against a corresponding one of the seals, setting the filler in a manner for the filler to remain adhered to the radially-inner face of the roller body, repeating the steps of pouring and setting against another one of the seals, on an opposite axial end of the conveyor roller. [0006] In accordance with still another aspect, there is provided a conveyor roller comprising a shaft, a roller body rotatably mounted around the shaft via bearings, the roller body having an inner core made of plastic, the roller body having a diameter greater than 5 inches. [0007] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.

DESCRIPTION OF THE FIGURES

[0008] In the figures, [0009] Fig. 1 is a front elevation view of an example of a conveyor segment, including three conveyor rollers, in accordance with the prior art; and

[0010] Fig. 2 is an oblique view of an embodiment of a conveyor roller;

[0011] Fig. 3 is an exploded view of the components of one axial end of the conveyor roller of Fig. 2; [0012] Figs 4A and 4B show a first assembly step of the conveyor roller of Fig. 2;

[0013] Figs 5A and 5B show a second assembly step of the conveyor roller of Fig. 2;

[0014] Figs 6 and 7 are oblique views of a labyrinth seal and of a master seal, respectively;

[0015] Fig. 8A is a partial oblique transversal cross-sectional view of one axial end of the conveyor roller during assembly, with the master seal and labyrinth seals assembled;

[0016] Fig. 8B is a view similar to Fig. 8A, but showing a filler having set;

[0017] Figs 9A, 9B and 9C are oblique views showing the assembly of an O-ring;

[0018] Figs 10A, 10B and 10C are oblique views showing the assembly of an end cap; [0019] Fig. 11 is an exploded view summarizing the assembly steps of the other axial end of the conveyor roller;

[0020] Figs. 12A and 12B illustrate the step of overmoulding a protective coating of the roller body.

DETAILED DESCRIPTION

[0021] Fig. 1 shows a portion of an example conveyor 100 which has a plurality of conveyor rollers 102. This example is illustrated simply to provide illustrative context of one possible application. As persons having ordinary skill in the art will know, there are countless applications of conveyors having various types and specialties, and the conveyor roller described below can be adapted to many possible applications.

[0022] Fig. 2 and 12B show an example of a conveyor roller 200 fully assembled. Fig. 3 is an exploded view showing the components to be assembled to a first axial end, and Fig. 11 is an exploded view showing the components to be assembled to the second axial end. The details of construction of this conveyor roller example will be presented following a possible assembly sequence, following Fig. 4A to Fig. 12B.

[0023] As perhaps best seen in Fig. 3, the conveyor roller 200 can have a shaft 202 around which a roller body 204 can be rotatably mounted via bearings 206. In a typical application, the roller 200 is held in a frame via the shaft 202, and the roller body 204 rotates around the shaft 202 during operation via the bearings 206.

[0024] This conveyor roller 200 embodiment is a heavy-duty configuration, and can be adapted to satisfy CEMA-E or CEMA-F requirements, even though it will be understood that lighter duty adaptations are possible. This embodiment has two bearings 206 at each axial end. In this specific embodiment, it was found convenient to provide the shaft 202 with a central portion 208 having a greater diameter than the two bearing receiving portions 210. The shaft 202 can be made of metal, and heavy duty aluminum can be selected, such as 7075T6 aeronautic grade aluminum for instance, if it is desired to provide relatively low weight in addition to strong mechanical resistance. Two bearings 206 can be press fitted onto each corresponding bearing receiving portion 210, e.g. by repeating the steps of Fig. 4A and 4B on each axial side, into abutting engagement with the step (shoulder) formed between the central portion 208 and the bearing receiving portions 210, and a snap ring 212 can be used on an axially-outer side of the bearings 206, to hold the bearings 206 into place. In this embodiment, NACHI™ 2RSC3 bearings were found satisfactory.

[0025] Once the bearings 206 have been assembled to the shaft 202, the roller body 204, or in this specific embodiment where the roller body 204 has more than one layer, the inner core 214 which forms the radially inner portion of the roller body 204, can be assembled by sliding engagement, as shown in Figs 5A and Fig. 5B. In some embodiments, it can be preferred to assemble the roller body 204 once the bearings 206 are fully engaged, and in some other embodiments, it can be preferred to assemble the roller body 204 once the bearings 206 of one axial end are assembled, and to then engage the bearings of the other axial end between the roller body 204 and the shaft 202, to name some examples.

[0026] Referring back to Fig. 2, it will be noted that an end cap 216 can be provided at each axial end. The end caps 216 can be secured to the shaft 202, such as by adhesion, soldering or brazing, for instance, in a manner to remain fixed relative to the shaft 202 while the roller body 204 rotates around it. This non-rotating feature of the end caps 216 has been found to be a significant asset in providing great durability and resisting wear and failure of the conveyor rollers 200 in some applications, because a foreign object trapped in engagement with the end cap 216 will not necessarily be forced into sliding frictional engagement with it as the roller body 204 rotates. The end caps 216 can be made of the same material as the shaft, for example.

[0027] In this embodiment, a sealing assembly is provided between each end cap 216 and the bearings 206, and the shaft 202 protrudes 217 axially from both end caps 216. The sealing assemblies used in this specific embodiment will now be detailed.

[0028] Turning to Fig. 8A, it can be seen that in this embodiment, the sealing assembly includes a labyrinth seal 218 applied against the axially outer face of the bearings 206. Grease can preferably be applied into the channels of the labyrinth seal 218, in the face of the labyrinth seal 218 which faces the bearings 206. A master seal 220 was then applied against the axially outer face of the labyrinth seal 218. Grease can be applied into the channel of the master seal 220, and on the contact face, on the side facing the labyrinth seal 218. The master seal 220 can feature sealing edges on front and back of the contact surface with the shaft 202, and can include a spring seal as known in the art. Synthetic grease rated between -60 and 400°F was found suitable in this embodiment. For reasons which will become apparent below, adhesive can be applied to the axially external face of the master seal.

[0029] As shown in Fig. 8A, the roller body 204 can be shaped in a manner to have a radially extending groove 222 extending circumferentially around the radially-inner face, at a location axially external to the master seal 220, in a portion of the roller body 204 which can be referred to as the filler cavity. As shown in Fig. 8B, a filler 224 can then be poured into the filler cavity, in a manner for the filler 224 to fill the area extending axially adjacent to the master seal 220, including the radially extending groove 222. The filler 224, which can be polyurea, polyurethane, epoxy or rubber, to name a few examples, can be selected in a manner to adhere to the master seal 220 and to the radially-inner face of the roller body 204. As discussed above, adhesive can be applied to favor adhesion, and adhesive can also be used on the radially-inner face of the roller body 204 to favor adhesion if desired. The engagement of the filler 224 with the radially extending groove 222 can form a locking engagement which prevents relative axial movement between the filler 224 and the roller body 204 once the filler 224 is set. In such an embodiment, it can be required to apply a mould-release agent onto the portion of the shaft 202 which will axially coincide with the filler 224, before applying the filler 224, to prevent any adhesion between the filler 224 and the shaft 202. Polyurea was used as the filler 224 in this embodiment, and can be considered to form part of the roller body 204 once set.

[0030] As shown in Fig. 9C, an O-ring 226 can now be applied to provide an additional seal component. The O-ring 226 can be applied in an axially-extending groove 228, which can be provided in an axial face or shoulder portion of the roller body 204, for instance, and extend circumferentially around the roller body 204. The purpose of this O-ring 226 will become apparent to the skilled reader upon further reading.

[0031] As shown in Figs 10A and 10B, the component which was referred to above as the end cap 216 can now be assembled. The end cap 216 can be a disc-shaped component which extends radially to bridge the diameter of the shaft 202 and the inner diameter of the roller body 204. The radially outer edge of the end cap 216 can become engaged with the O- ring 226, to provide a seal between the end cap 216 and the roller body 204. In this embodiment, the end cap 216 is secured to the shaft 202, and becomes integral thereto. This can be achieved by welding, brazing or adhering, for instance. In this embodiment, a radially inner, axially-outer edge of the end cap 216 is provided with a bevel 230 which is filled with loctite™ aluminum bonder adhesive to perform the securing function, and simultaneously seal the radially-inner edge of the end cap 216.

[0032] Similar steps to those presented above can now be repeated on the other axial end of the conveyor roller 200, as schematized in Fig. 11.

[0033] In this embodiment, the roller body 204 includes an inner core 214 and a roller surface 232 (external). The inner core 214 is made from plastic, even though the roller body 204 can have more than 5, more than 6, more than 7, and even up to 12 inches in diameter, for instance. HDPE was used as the plastic in this embodiment. The use of plastic was found to contribute to providing a roller 200 which generated very little noise during operation. The combined use of a filler 224 at each axial end of the roller body 204, and the use of a polymeric roller surface 232, were also found to contribute to the low noise feature of this embodiment. In this embodiment, the roller surface 232 was overmoulded onto the inner core 214. Polyurea was selected for the material of the roller surface 232 in this embodiment, although it will be understood that other materials may be found suitable in alternate embodiments. As shown in Fig. 12A, the radially-external surface of the inner core 214 can be provided with a combination of axially and circumferentially extending grooves 234 which the roller surface 232 engages upon overmoulding, ensuring that the roller surface 232 stays integral with the inner core 214 during operation. In this embodiment, the O-ring 226 is a felt O-ring.

[0034] As can be understood, the examples described above and illustrated are intended to be exemplary only. In another embodiment, the roller body 204, or an inner core 214 thereof, can be made of metal, for example. The scope is indicated by the appended claims.